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Articles 17671 - 17700 of 30237

Full-Text Articles in Mechanical Engineering

Simultaneous Monitoring Of Singlet And Triplet Exciton Variations In Solid Organic Semiconductors Driven By An External Static Magnetic Field, Baofu Ding, Kamal Alameh Jan 2014

Simultaneous Monitoring Of Singlet And Triplet Exciton Variations In Solid Organic Semiconductors Driven By An External Static Magnetic Field, Baofu Ding, Kamal Alameh

Research outputs 2014 to 2021

The research field of organic spintronics has remarkably and rapidly become a promising research area for delivering a range of high-performance devices, such as magnetic-field sensors, spin valves, and magnetically modulated organic light emitting devices (OLEDs). Plenty of microscopic physical and chemical models based on exciton or charge interactions have been proposed to explain organic magneto-optoelectronic phenomena. However, the simultaneous observation of singlet- and triplet-exciton variations in an external magnetic field is still unfeasible, preventing a thorough theoretical description of the spin dynamics in organic semiconductors. Here, we show that we can simultaneously observe variations of singlet excitons and triplet …


Review Of High-Temperature Central Receiver Designs For Concentrating Solar Power, Brian D. Iverson, Clifford K. Ho Jan 2014

Review Of High-Temperature Central Receiver Designs For Concentrating Solar Power, Brian D. Iverson, Clifford K. Ho

Faculty Publications

This paper reviews central receiver designs for concentrating solar power applications with high-temperature power cycles. Desired features include low-cost and durable materials that can withstand high concentration ratios (~1000 suns), heat-transfer fluids that can withstand temperatures > 650°C, high solar absorptance, and low radiative and convective heat losses leading to a thermal efficiency > 90%. Different receiver designs are categorized and evaluated in this paper: (1) gas receivers, (2) liquid receivers, and (3) solid particle receivers. For each design, the following information is provided: general principle and review of previous modeling and testing activities, expected outlet temperature and thermal efficiency, benefits, perceived …


Sensitivity Analysis Of Wind Plant Performance To Key Turbine Design Parameters: A Systems Engineering Approach, Katherine Dykes, Andrew Ning, Ryan King, Peter Graf, George Scott, Paul Veers Jan 2014

Sensitivity Analysis Of Wind Plant Performance To Key Turbine Design Parameters: A Systems Engineering Approach, Katherine Dykes, Andrew Ning, Ryan King, Peter Graf, George Scott, Paul Veers

Faculty Publications

This paper introduces the development of a new software framework for research, design, and development of wind energy systems which is meant to 1) represent a full wind plant including all physical and nonphysical assets and associated costs up to the point of grid interconnection, 2) allow use of interchangeable models of varying fidelity for different aspects of the system, and 3) support system level multidisciplinary analyses and optimizations. This paper describes the design of the overall software capability and applies it to a global sensitivity analysis of wind turbine and plant performance and cost. The analysis was performed using …


Evaluation Of Solar Energy Solution For Egyptian Remote Areas, Tarek Ihab Abdelsalam, Tarek M. Hatem Jan 2014

Evaluation Of Solar Energy Solution For Egyptian Remote Areas, Tarek Ihab Abdelsalam, Tarek M. Hatem

Mechanical Engineering

Egypt is currently suffering the symptoms of the energy crises, such as electricity outage and high deficit as a result of constant increase in fossil foils through the last decades. On the other hand, Egypt has a high solar availability of more than 18.5 MJ annually. Additionally, Egypt has large uninhabited deserts on both sides of the Nile valley and in Sinai Peninsula, which represent more than 96.5% of the nation’s total land area. Therefore, solar energy is one of the prospective solutions for energy shortage in Egypt. Furthermore, these vast lands are advantageous for commissioning huge solar power generation …


Fault-Tolerant Trajectory Tracking Of Unmanned Aerial Vehicles Using Immunity-Based Model Reference Adaptive Control, Brenton K. Wilburn Jan 2014

Fault-Tolerant Trajectory Tracking Of Unmanned Aerial Vehicles Using Immunity-Based Model Reference Adaptive Control, Brenton K. Wilburn

Graduate Theses, Dissertations, and Problem Reports (ETD)

This dissertation presents the design, development, and simulation testing of an adaptive trajectory tracking algorithm capable of compensating for various aircraft subsystem failures and upset conditions. A comprehensive adaptive control framework, here within referred to as the immune model reference adaptive control (IMRAC) algorithm, is developed by synergistically merging core concepts from the biologically- inspired artificial immune system (AIS) paradigm with more traditional optimal and adaptive control techniques. In particular, a model reference adaptive control (MRAC) algorithm is enhanced with the detection and learning capabilities of a novel, artificial neural network augmented AIS scheme. With the given modifications, the MRAC …


Electroplating Of Cr-Ni Alloy And Ni-Cr/Ni Multilayer Coatings, Liaowang Liu Jan 2014

Electroplating Of Cr-Ni Alloy And Ni-Cr/Ni Multilayer Coatings, Liaowang Liu

Graduate Theses, Dissertations, and Problem Reports (ETD)

The major interests of developing Ni-Cr alloy plating lie in the possible formation of a passive film by chromium and its good chemical and mechanical properties. And nano scale multilayer coatings exhibit improved properties due to nano scale effects (e.g.: high hardness and strength) and they combine and enhance different properties from individual components. Thus, electroplating of Ni-Cr multilayer coatings could have high potential for numerous engineering applications. Electroplating in aqueous and in organic solution by direct current were studied for Ni-Cr alloy coatings, and Ni-Cr multilayer coatings were prepared by pulse current electroplating in single bath.

Traditionally, chromium or …


Pitting Corrosion And Corrosion Fatigue Crack Growth Behavior Of Oil-Grade Alloy 718 In Sodium Chloride Solution, Ting Chen Jan 2014

Pitting Corrosion And Corrosion Fatigue Crack Growth Behavior Of Oil-Grade Alloy 718 In Sodium Chloride Solution, Ting Chen

Graduate Theses, Dissertations, and Problem Reports (ETD)

Oil-grade nickel-base alloy 718 has been recently used in the oil and gas industry for downhole drilling components especially for the parts of the bottom hole assembly (BHA) due to its superior mechanical properties, good corrosion resistance, non-magnetic properties and ability to be heat treated to various strength levels. As the modern oil and gas industry explored into coastal and marine locations, deeper and deeper wells have been drilled with high pressure high temperature, making the demand for increased strength and good toughness super critical for alloys used in ultra-deep wells drilling. Moreover, the existence of high concentrations of chloride …


Comparison Of Manufacturing Techniques For Composites Subjected To High Speed Impact, Kenneth Gollins Jan 2014

Comparison Of Manufacturing Techniques For Composites Subjected To High Speed Impact, Kenneth Gollins

Dissertations and Theses

No abstract provided.


Association Of Lean Implementation On Perceived Organizational Maturity Levels Of Managers And Staff In The Public Sector, Patrick Eduardo O'Mara Jan 2014

Association Of Lean Implementation On Perceived Organizational Maturity Levels Of Managers And Staff In The Public Sector, Patrick Eduardo O'Mara

LSU Master's Theses

Extensive research has shown the impact of Lean implementation at the process level of an organization to increase quality, reduce cycle time, and reduce operational costs. However, little research has been done to associate Lean with improvement at the strategic level of an organization. The objectives of the present research were to (a) study the association of Lean implementation with maturity levels of employees (b) study the relationship between Lean implementation in the levels of agreement with cohesion between managers and staff in evaluating perceived current state and desired state of organizational practices (c) identify potential barriers of Lean implementation …


Thermal And Cooling Systems Modeling Of Powertrain For A Plug -In Parallel-Through-The-Road Hybrid Electric Vehicle, Mengjia Cao Jan 2014

Thermal And Cooling Systems Modeling Of Powertrain For A Plug -In Parallel-Through-The-Road Hybrid Electric Vehicle, Mengjia Cao

Wayne State University Theses

Thermal modeling and control play an ever increasing role with hybrid electric vehicle (HEV) design and development for improving overall vehicle energy efficiency, and to account for additional thermal loading from electric powertrain components such as electric motor, motor controller and battery pack.

This thesis presents a complete development process for an efficient modeling approach with integrated control strategy for the thermal management of plug-in HEV in a parallel-through-the road (PTTR) architecture, adopted by Wayne State University Hybrid Warriors for their Department of Energy's EcoCAR2 Plugging in to the Future Competition.

The frameworks of this project include simulating the thermal …


Investigation Of Ion Current Signal In A Modern Automotive Diesel Engine, Rojan Mathew George Jan 2014

Investigation Of Ion Current Signal In A Modern Automotive Diesel Engine, Rojan Mathew George

Wayne State University Theses

Research is driven towards finding an alternative or extender to the conventional diesel fuel for compression ignition engines. Such alternative fuels have wide ranges of physical and chemical properties which is not suitable for CI engines. Therefore, experimental investigation to understand the effects of different fuels on engine performance, combustion, and emissions are necessary. A complete understanding of ion current signal during heterogeneous diesel combustion has not yet been made. Implementation of ion current signal as a feedback in diesel engines, during all operating conditions needs further research and understanding.

This thesis covers the investigation of ion current signal characteristics …


An Investigation Of Kinetic Effects Of Split Injection Timing On Low Temperature Combustion, Tejaswini A. Kamble Jan 2014

An Investigation Of Kinetic Effects Of Split Injection Timing On Low Temperature Combustion, Tejaswini A. Kamble

Wayne State University Theses

Low temperature combustion (LTC) modes of operating internal combustion engines are of great interest for their potential to achieve high thermal efficiencies while maintaining low nitrogen oxide (NOX) and particulate matter emissions below levels requiring costly after-treatment systems. While various strategies for realizing LTC have been developed, including homogeneous charge compression ignition (HCCI), reactivity controlled compression ignition (RCCI) and premixed charge compression ignition (PCCI), a common challenge is the control of the kinetically-driven auto-ignition processes over appreciable load ranges.

This study examines the chemical kinetics of split-injection timing and the kinetic effect of this parameter on combustion phasing and pressure …


Long Life Electrochemical Diodes For Continuous Electrowetting, Mehdi Khodayari, Ben Hahne, Nathan B. Crane Jan 2014

Long Life Electrochemical Diodes For Continuous Electrowetting, Mehdi Khodayari, Ben Hahne, Nathan B. Crane

Faculty Publications

The rate of electrochemical reactions in some systems varies with the polarity of the overpotential on the working electrode, introducing diode-like behavior at the electrode/electrolyte interface. However, with repeated bipolar cycling, the electrochemical current damages the electrodes. We have connected electrochemical diodes in series with opposing polarities to reduce the diode current while charging a capacitive circuit. We have previously used this capacitive circuit arrangement to actuate aqueous droplets continuously using the electrowetting (EW) effect. In this study, the performance of electrochemical diodes under repeated voltage cycles is investigated. Aluminum and titanium electrodes in contact with three electrolyte solutions (0.1 …


Measuring The Effectiveness Of Education For Sustainable Development Interventions For Effecting Change In Knowledge, Attitude And Behaviors Toward Sustainable Development, Christopher Robin Wilson Jan 2014

Measuring The Effectiveness Of Education For Sustainable Development Interventions For Effecting Change In Knowledge, Attitude And Behaviors Toward Sustainable Development, Christopher Robin Wilson

Theses and Dissertations

The question addressed by this study is whether an intervention involving a brief, focused seminar providing Sustainability Fundamental education can affect change in sustainability-centric behavior via measured change in attitude toward sustainability and/or change knowledge of sustainability fundamentals.

This study focused on applying and extending lessons from a previous exploration of the relationships between sustainable behavior and both attitude toward sustainability and knowledge of sustainability. The test involved determining whether brief, science-based sustainability fundamentals seminars are an effective intervention for affecting the favorable sustainable behavior of practicing engineers, defined as professionals engaged in engineering post-completion of their formal studies, in …


The Effect Of Surface Corrosion Damage On The Fatigue Life Of Extruded Aluminum Alloy 6061-T6, Matthew Weber Jan 2014

The Effect Of Surface Corrosion Damage On The Fatigue Life Of Extruded Aluminum Alloy 6061-T6, Matthew Weber

UNF Graduate Theses and Dissertations

Aluminum alloy 6061-T6 is a common engineering material used in aerospace, automotive, structural applications. Despite its wide use, little has been published about the effects of damage from surface corrosion on its fatigue life. An investigation was performed where 6061-T6 extrusions were exposed to a 3.5% NaCl solution at pH 2 for 2 days and 24 days. The length of time and pH were chosen in order to create distinct surface flaws. The effect of these flaws on the fatigue life was then investigated and analyzed using scanning electron microscopy (SEM) and Weibull statistics. It was determined that samples corroded …


Fluid-Structure Interaction Simulations Of A Flapping Wing Micro Air Vehicle, Alex W. Byrd Jan 2014

Fluid-Structure Interaction Simulations Of A Flapping Wing Micro Air Vehicle, Alex W. Byrd

Browse all Theses and Dissertations

Interest in micro air vehicles (MAVs) for reconnaissance and surveillance has grown steadily in the last decade. Prototypes are being developed and built with a variety of capabilities, such as the ability to hover and glide. However, the design of these vehicles is hindered by the lack of understanding of the underlying physics; therefore, the design process for MAVs has relied mostly on trial-and-error based production. Fluid-Structure Interaction (FSI) techniques can be used to improve upon the results found in traditional computational fluid dynamics (CFD) simulations. In this thesis, a verification of FSI is first completed, followed by FSI MAV …


Nebraska Summary: S956 Challenger Mt485d, Nebraska Tractor Test Lab Jan 2014

Nebraska Summary: S956 Challenger Mt485d, 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: S955 Massey Ferguson 6615, Nebraska Tractor Test Lab Jan 2014

Nebraska Summary: S955 Massey Ferguson 6615, 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: S948 New Holland T4.115, Nebraska Tractor Test Lab Jan 2014

Nebraska Summary: S948 New Holland T4.115, 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: S945 New Holland T4.85, Nebraska Tractor Test Lab Jan 2014

Nebraska Summary: S945 New Holland T4.85, 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: S943 Case-Ih Farmall 105c, Nebraska Tractor Test Lab Jan 2014

Nebraska Summary: S943 Case-Ih Farmall 105c, 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: S942 Case-Ih Farmall 95c, Nebraska Tractor Test Lab Jan 2014

Nebraska Summary: S942 Case-Ih Farmall 95c, 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: S941 Case-Ih Farmall 85c, Nebraska Tractor Test Lab Jan 2014

Nebraska Summary: S941 Case-Ih Farmall 85c, 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 …


Test 2093a: New Holland T9.480, Nebraska Tractor Test Lab Jan 2014

Test 2093a: New Holland T9.480, 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 …


Test 2092a: New Holland T9.435, Nebraska Tractor Test Lab Jan 2014

Test 2092a: New Holland T9.435, 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 …


Test 2091: John Deere 7290r, Nebraska Tractor Test Lab Jan 2014

Test 2091: John Deere 7290r, 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 …


Test 2088: Challenger Mt765e, Nebraska Tractor Test Lab Jan 2014

Test 2088: Challenger Mt765e, 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 …


Test 2104: Massey Ferguson 7622 Dyna 6, Nebraska Tractor Test Lab Jan 2014

Test 2104: Massey Ferguson 7622 Dyna 6, 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 …


Test 2104a: Challenger Mt575d Ap6, Nebraska Tractor Test Lab Jan 2014

Test 2104a: Challenger Mt575d Ap6, 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 …


Modelling Of Directed Energy Deposition Processes, Xueyang Chen Jan 2014

Modelling Of Directed Energy Deposition Processes, Xueyang Chen

Masters Theses

"The laser additive manufacturing technique of laser deposition allows quick fabrication of fully-dense metallic components directly from Computer Aided Design (CAD) solid models. The applications of laser deposition include rapid prototyping, rapid tooling and part refurbishment. The development of an accurate predictive model for laser deposition is extremely complicated due to the multitude of process parameters and materials properties involved. In this work, a heat transfer and fluid flow model is developed.

In the heat transfer and fluid flow model, the governing equations for solid, liquid and gas phases in the calculation domain have been formulated using the continuum model. …