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California Polytechnic State University, San Luis Obispo

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Articles 6811 - 6840 of 7976

Full-Text Articles in Engineering

Design, Fabrication, Modeling And Characterization Of Electrostatically-Actuated Silicon Membranes, Brian C. Stahl Dec 2008

Design, Fabrication, Modeling And Characterization Of Electrostatically-Actuated Silicon Membranes, Brian C. Stahl

Master's Theses

This thesis covers the design, fabrication, modeling and characterization of electrostatically actuated silicon membranes, with applications to microelectromechanical systems (MEMS). A microfabrication process was designed to realize thin membranes etched into a silicon wafer using a wet anisotropic etching process. These flexible membranes were bonded to a rigid counterelectrode using a photo-patterned gap layer. The membranes were actuated electrostatically by applying a voltage bias across the electrode gap formed by the membrane and the counterelectrode, causing the membrane to deflect towards the counterelectrode. This deflection was characterized for a range of actuating voltages and these results were compared to the …

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Load Sharing Characteristic Of Single Phase Pv Inverter Connected To Grid, M. Imram Hamid, Makbul Anwari, Z. Salam, Taufik Dec 2008

Load Sharing Characteristic Of Single Phase Pv Inverter Connected To Grid, M. Imram Hamid, Makbul Anwari, Z. Salam, Taufik

Electrical Engineering

This paper describes model and simulation of single phase PV inverters that work independently to supply three phase system as a part of renewable distributed generation. Load sharing characteristic of PV inverter and grid during supplying local load with current control method and relation of PV power level and current control performance to load sharing are simulated and analyzed. Furthermore, power quality behavior during connection/disconnection of PV plant, grid harmonics, voltage and current unbalance are simulated and analyzed. Model and simulation are implemented using MATLAB/Simulink.

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A Small Scale Static Var Compensator For Laboratory Experiment, Taufik, Bryan Paet Dec 2008

A Small Scale Static Var Compensator For Laboratory Experiment, Taufik, Bryan Paet

Electrical Engineering

This paper presents a small scale static VAR compensator (SVC) circuit that could be used as either a laboratory demonstration or a laboratory experiment. The small scale SVC lab experiment effectively demonstrates SVCpsilas function in correcting power factor through the use of power thyristors in a phase-controlled circuit. The laboratory setup of the SVC circuit using a thyristor controlled reactor in parallel with a capacitor will discussed in this paper. Results from the lab setup to exhibit firing angle adjustment to inject or absorb VARs into the system will also be described.

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Impact Of Multiple Adjustable Speed Drive System To Power System Harmonics, Taufik, Erin Matsumoto, Makbul Anwari Dec 2008

Impact Of Multiple Adjustable Speed Drive System To Power System Harmonics, Taufik, Erin Matsumoto, Makbul Anwari

Electrical Engineering

This paper presents harmonic analysis in a multiple adjustable speed drive system. In a system where multiple drives are fed from the same bus, harmonic currents produced by the various drives can reflect back to the power source and to the other drives causing distortion of the voltage waveform. If these harmonic currents are significant, they can potentially cause problems for the given system. Therefore studying the harmonics at various points in the system and comparing the values of total harmonic distortion can provide guidance in choosing appropriate filtering solutions. A two AC drive system was setup in a laboratory …

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Power Quality Behavior Of Single Phase Fed Adjustable Speed Drive Supplied From Grid Of Pv Generation, Makbul Anwari, M. Imran Hamid, Taufik Dec 2008

Power Quality Behavior Of Single Phase Fed Adjustable Speed Drive Supplied From Grid Of Pv Generation, Makbul Anwari, M. Imran Hamid, Taufik

Electrical Engineering

Power quality behavior on connecting single phase fed adjustable speed drives to a grid which photovoltaic as the power generation is studied in this paper. A MATLAB/Simulink simulations are performed to investigate the existence of power quality parameter and the system problems that may be resulted from operation of this type of load. The results indicate a potential serious power quality problem with the connected adjustable speed drives, which requires consideration during operation of PV generation which a number of this dynamic load.

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Utilizing Quantum Dots To Enhance Solar Spectrum Conversion Efficiencies For Photovoltaics, Richard N. Savage, Hans Mayer, Matthew Lewis, Dan M. Marrujo Dec 2008

Utilizing Quantum Dots To Enhance Solar Spectrum Conversion Efficiencies For Photovoltaics, Richard N. Savage, Hans Mayer, Matthew Lewis, Dan M. Marrujo

Materials Engineering

Silicon-based photovoltaics typically convert less than 30% of the solar spectrum into usable electric power. This study explores the utilization of CdSe based quantum dots as spectral converters that absorb the under utilized UV portion of the solar spectrum and fluoresce at wavelengths near the band-gap of silicon-based solar cells. A flexible 1 mm thick thin-film structure that contains an array of microfluidic channels is designed and fabricated in polydimethylsiloxane (PDMS) using soft-lithographic techniques. The channels are approximately 85 microns wide by 37 microns tall and are filled with a solution containing the quantum dots. The thin-film structure can easily …

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Bioflocculation For Control Of Wastewater Pond Microalgae, Daniel Thomas Frost Dec 2008

Bioflocculation For Control Of Wastewater Pond Microalgae, Daniel Thomas Frost

Master's Theses

Investigates several hypotheses regarding the use of bioflocculation as a harvesting method for wastewater pond microalgae. Research performed on pilot-scale high rate ponds (HRPs) on the California Central Coast.

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Application Of Parent-Child Uav Tasking For Wildfire Detection And Response, Stephen T. Kubik Dec 2008

Application Of Parent-Child Uav Tasking For Wildfire Detection And Response, Stephen T. Kubik

Master's Theses

In recent years, unmanned aerial vehicles (UAVs) have become a dominant force in the aerospace industry. Recent technological developments have moved these aircraft from remote operation roles to more active response missions. Of particular interest is the possibility of applying UAVs toward solving complex problems in long-endurance missions. Under that belief, the feasibility of utilizing UAVs for wildfire detection and response was investigated in a partnership that included NASA’s Aeronautics Research Mission Directorate and Science Mission Directorate, and the United States Forest Service. Under NASA’s Intelligent Mission Management (IMM) project, research was conducted to develop a mission architecture that would …

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A Novel Method For Characterization Of Peripheral Nerve Fiber Size Distributions By Group Delay, Robert B. Szlavik Dec 2008

A Novel Method For Characterization Of Peripheral Nerve Fiber Size Distributions By Group Delay, Robert B. Szlavik

Biomedical Engineering

The ability to determine the characteristics of peripheral nerve fiber size distributions would provide additional information to clinicians for the diagnosis of specific pathologies of the peripheral nervous system. Investigation of these conditions, using electrodiagnostic techniques, is advantageous in the sense that such techniques tend to be minimally invasive yet provide valuable diagnostic information. One of the principal electrodiagnostic tools available to the clinician is the nerve conduction velocity test. While the peripheral nerve conduction velocity test can provide useful information to the clinician regarding the viability of the nerve under study, it is a single-parameter test that yields no …

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Dynamic Analysis Of Less-Than-Truckload Shipments And Test Method To Simulate This Environment, Sher Paul Singh, E. Joneson, Jay Singh, G. Grewal Dec 2008

Dynamic Analysis Of Less-Than-Truckload Shipments And Test Method To Simulate This Environment, Sher Paul Singh, E. Joneson, Jay Singh, G. Grewal

Industrial Technology and Packaging

This paper provides results from a comprehensive data measurement study that analyzed the vibration dynamics produced inside the trailers used for less-than truckload (LTL) shipments. The trailers used for this segment of the package transportation environment are very different in size and suspension than those used for full truckload shipments. This study measured the vertical, lateral and longitudinal vibration inside a trailer as a function of road surface. In addition, the study developed a video showing freight movement inside the trailer to determine physical displacement and shifting of the loads. A set of recommendations was developed to safely load and …

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High Speed Wavelength Tuning Of Sgdbr Lasers For Optical Coherence Tomography Applications, Benjamin Maher Dec 2008

High Speed Wavelength Tuning Of Sgdbr Lasers For Optical Coherence Tomography Applications, Benjamin Maher

Master's Theses

The application of Sample Grated Distributed Bragg Reflector (SGDBR) wavelength tunable lasers for swept-wavelength Optical Coherence Tomography (OCT) is explored. OCT is a method of measuring reflectivity versus distance into samples under test with a focused infrared light source. Swept wavelength OCT requires a laser light source that is capable of sweeping its wavelength quickly over the entire wavelength range of the tunable laser. Fast sweeping of the laser's wavelength enables real-time imaging of a wide surface area of the surface under test. This thesis will show that SGDBR lasers can be designed to meet the fast wavelength ramp speeds …

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Analysis And Design Of Interleaving Multiphase Dc-To-Dc Converter With Input Lc Filter, Kevin Thomas Delrosso Dec 2008

Analysis And Design Of Interleaving Multiphase Dc-To-Dc Converter With Input Lc Filter, Kevin Thomas Delrosso

Master's Theses

The future of microprocessors is unknown. Over the past 40 years, their historical trend has been for adopting smaller and more powerful designs that drive the world that we live in today. The state of the microprocessor business today faces a crossroad, wishing to continue on the historical trend of doubling the number of transistors on a chip every 18 months (Moore’s Law) but also facing the realistic task of needing to power these sophisticated devices. With the low voltages and high currents that are required for these microprocessors to operate, it poses a difficult task for the future designers …

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A Computer-Based Economic Analysis For Manufacturing Process Selection, Manocher Djassemi Nov 2008

A Computer-Based Economic Analysis For Manufacturing Process Selection, Manocher Djassemi

Industrial Technology and Packaging

An important part of financial planning in product development is considering whether the capital expenditures meet volume and cost goals. A good business plan should provide investors with the implications of process selection on the company's bottom line. It is estimated that there are least 1000 manufacturing processes and sub-processes. Considering the number of process choices and quantity of cost data, an economic analysis for process selection may pose a challenge for decision makers. This paper provides an insight to Ashby’s cost modeling method for generating an estimate of unit product cost. The cost model provides a broad indicator for …

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Fpga Acceleration Of Mean Variance Framework For Optimal Asset Allocation, Ali Irturk, Bridget Benson, Nikolay Laptev, Ryan Kastner Nov 2008

Fpga Acceleration Of Mean Variance Framework For Optimal Asset Allocation, Ali Irturk, Bridget Benson, Nikolay Laptev, Ryan Kastner

Electrical Engineering

Asset classes respond differently to shifts in financial markets, thus an investor can minimize the risk of loss and maximize return of his portfolio by diversification of assets. Increasing the number of diversified assets in a financial portfolio significantly improves the optimal allocation of different assets giving better investment opportunities. However, a large number of assets require a significant amount of computation that only high performance computing can currently provide. Because of the highly parallel nature of Markowitzpsila mean variance framework (the most popular approximation approach for optimal asset allocation) an FPGA implementation of the framework can also provide the …

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Generation Of High Speed, Linear Wavelength Sweeps Using Sampled Grating Distributed Bragg Reflector Lasers, Shane O' Connor, Michael A. Bernacil, Dennis Derickson Nov 2008

Generation Of High Speed, Linear Wavelength Sweeps Using Sampled Grating Distributed Bragg Reflector Lasers, Shane O' Connor, Michael A. Bernacil, Dennis Derickson

Electrical Engineering

Wavelength-tunable sampled grating distributed Bragg reflector (SG-DBR) lasers are used for telecommunications applications in which the laser is set to a communication channel and changed infrequently. SG-DBR lasers can be tuned to any wavelength over a 50 nm tuning range with fast transition times using a set of three control currents. This paper demonstrates generation of fast linear wavelength ramps covering the entire tuning range of the laser. Continuous and linear wavelength sweeps are achieved by applying three time synchronized waveforms to the front mirror, back mirror, and phase sections of the laser. Continuous wavelength coverage is achieved by appending …

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Drop Impact Dynamic Response Study Of Jedec Jesd22-B111 Test Board, Michael Krist, Jianbiao Pan, Andrew Farris, Nicolas Vickers Nov 2008

Drop Impact Dynamic Response Study Of Jedec Jesd22-B111 Test Board, Michael Krist, Jianbiao Pan, Andrew Farris, Nicolas Vickers

Industrial and Manufacturing Engineering

Mobile and handheld electronic devices are prone to being dropped. This drop event may result in failure of solder joints inside these devices. The need for RoHS compliant boards coupled with the demand for reliable electronics has resulted in the development of the JEDEC Standard JESD22-B111 to standardize the method of drop testing surface mount electronic components. However, there has been little study on the effects of additional mass on the board and rigidity of the board on drop test reliability. This paper examines the drop impact dynamic responses of the JEDEC JESD22-B111 board. Of interest are the effects of …

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The Effect Of Ultrasonic Frequency On Gold Wire Bondability And Reliability, Jianbiao Pan, Minh-Nhat Le, Cuong Van Pham Nov 2008

The Effect Of Ultrasonic Frequency On Gold Wire Bondability And Reliability, Jianbiao Pan, Minh-Nhat Le, Cuong Van Pham

Industrial and Manufacturing Engineering

This paper presents a systematic study on the effect of 120KHz ultrasonic frequency on the bondability and reliability of fine pitch gold wire bonding. The study was carried out on a thermosonic ball bonder that is allowed to easily switch between ultrasonic frequency of 60KHz and 120 KHz by changing the ultrasonic transducer and the ultrasonic generator. Bonding parameters were optimized through design of experiment methodology for four different cases: 25.4 μm wire at 60 kHz, 25.4 μm wire at 120 kHz, 17.8 μm wire at 60 kHz, and 17.8 μm wire at 120 kHz. The integrity of wire bonds …

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Board Level Failure Analysis Of Chip Scale Package Drop Test Assemblies, Nicholas Vickers, Kyle Rauen, Andrew Farris, Jianbiao Pan Nov 2008

Board Level Failure Analysis Of Chip Scale Package Drop Test Assemblies, Nicholas Vickers, Kyle Rauen, Andrew Farris, Jianbiao Pan

Industrial and Manufacturing Engineering

This paper presents the failure analysis results of board level drop tests. In this study, the test vehicle was designed according to the requirements of the Joint Electron Device Engineering Council (JEDEC) drop test board. The test vehicle was assembled with 15 chip scale packages (CSPs) each having 228 daisy-chained 0.5 mm pitch solder joints using Sn-3.0 wt% Ag-0.5 wt% Cu (SAC305) lead free solder. Assemblies were drop tested using three different peak accelerations of 900 G, 1500 G, 2900 G, with 0.7 ms, 0.5 ms, and 0.3 ms pulse durations, respectively. Scanning electron microscopy (SEM) with energy dispersive spectroscopy …

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Canal Seepage Reduction By Soil Compaction, Charles M. Burt, Marcus Gardenas, Mohamed Grissa Nov 2008

Canal Seepage Reduction By Soil Compaction, Charles M. Burt, Marcus Gardenas, Mohamed Grissa

BioResource and Agricultural Engineering

Large-scale tests were conducted of in-place compaction of irrigation district earthen canal bottoms and sides. Five canal pools with sandy loam soils were compacted. Seepage reduction of about 86% was obtained when the sides and bottoms were compacted; reductions of 12 – 31% were obtained when only sides were compacted.

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Improving Pump Performance, Charles M. Burt, Frankline Gaudi, Daniel J. Howes Nov 2008

Improving Pump Performance, Charles M. Burt, Frankline Gaudi, Daniel J. Howes

BioResource and Agricultural Engineering

Options can be specified to minimize power consumption by vertical pumps – both when new and over the life of the pump. Options discussed include bowl coatings, proper well development, improved suction screens, using closed impeller designs, increasing column size, using new bearings, providing proper bearing lubrication, impeller balancing, and polishing impellers. The proper TDH and flow rate must be specified, and the advantages of VFD controls are covered.

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Thermal Analysis Of Cover Systems In Municipal Solid Waste Landfills, Nazli Yesiller, James Hanson, Nicolas K. Oettle, Wei-Lien Liu Nov 2008

Thermal Analysis Of Cover Systems In Municipal Solid Waste Landfills, Nazli Yesiller, James Hanson, Nicolas K. Oettle, Wei-Lien Liu

Civil and Environmental Engineering

Cover temperature variations were determined at four municipal solid waste landfills located in different climatic regions in North America: Michigan, New Mexico, Alaska, and British Columbia. Cover temperatures varied seasonally similarly to air temperatures and demonstrated amplitude decrement and phase lag with depth. Elevated temperatures in the underlying wastes resulted in warmer temperatures and low frost penetration in the covers compared to surrounding subgrade soils. The ranges of measured temperatures decreased and average temperatures generally increased (approximately 2°C/m) with depth. The ranges of measured temperatures (Tmax−Tmin) were 18–30°C and 13–21°C and the average temperatures …

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Control And Sensor Development On A Four-Wheel Pyramidal Reaction Wheel Platform, Jeffery Jay Logan Nov 2008

Control And Sensor Development On A Four-Wheel Pyramidal Reaction Wheel Platform, Jeffery Jay Logan

Master's Theses

The Pyramidal Reaction Wheel Platform, or PRWP, is used to simulate three-axis controls in a torque free space-like environment. The primary purpose of the system will be to evaluate the effects of conjoining sensors to maximize pointing accuracy. Furthermore, the system will incorporate a star tracker in conjunction with a Simulated Star Field (SSF) to better estimate the PRWP orientation. For the sake of this document, however, the goal is to implement a gyroscope, wheel rate sensors, and a make-shift accelerometer—to the PRWP—and integrate a controls algorithm such that three-axis controls are achieved for the PRWP. Three sensors were either …

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Design And Optimization Of A Blood Vessel Mimic Bioreactor System For The Evaluation Of Intravascular Devices In Simple And Complex Vessel Geometries, Sara M. Leifer Nov 2008

Design And Optimization Of A Blood Vessel Mimic Bioreactor System For The Evaluation Of Intravascular Devices In Simple And Complex Vessel Geometries, Sara M. Leifer

Master's Theses

Coronary artery disease affects millions of people and the ability to detect and treat the disease is advancing at a rapid rate. As a result, the development of intravascular technologies is the focus of many medical device manufacturers. Specifically, coronary stent implantation is being performed in an increasing number of patients and a number of new stent designs have been introduced to the market, resulting in the need for improved preclinical testing methods. An in vitro tissue engineered “blood vessel mimic” (BVM) system has previously been established and its feasibility for the initial testing of newly emerging intravascular technology has …

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Work In Progress - Attaining And Measuring Global Competency For Engineering Graduates, James Widmann, Linda Vanasupa Oct 2008

Work In Progress - Attaining And Measuring Global Competency For Engineering Graduates, James Widmann, Linda Vanasupa

Materials Engineering

Downey et al. laid out a clear path of learning criteria and outcomes for global competence in their 2006 Journal of Engineering Education publication. We build on their work by integrating other disciplinary perspectives to expand upon the questions: "How can global competency be learned?", and "How can we assess it?" In this work-in-progress paper, we propose an expanded framework for global competence and identify the use of Fink's taxonomy of significant learning as a tool to consider how it can be achieved through careful design of classroom learning experiences. Drawing heavily from other models, our framework attempts to articulate …

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Work In Progress - A Design Guide To Retain Female (And Male) Students In Engineering, Linda Vanasupa, Katherine C. Chen, Stacey Breitenbach, Karen R. Bangs Oct 2008

Work In Progress - A Design Guide To Retain Female (And Male) Students In Engineering, Linda Vanasupa, Katherine C. Chen, Stacey Breitenbach, Karen R. Bangs

Materials Engineering

Despite a rich body of research on factors contributing to attrition of women during the college, women continue to be underrepresented in the graduating classes of most traditional engineering disciplines. We present our Four-Domain Development Diagram (4DDD) in an attempt to enable a systems approach to managing all the factors that contribute to retention. This diagram makes explicit the connections between the learners' response factors in the learning environment, including motivation, interest, and ultimately retention. Although we are only three years into our use of the diagrams' relationships, we have seen a lower overall net attrition rate (male and female) …

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Work In Progress - Enhancing Student-Learning Through State-Of-The-Art Systems Level Design And Implementation, Albert A. Liddicoat, Jianbiao Pan, James G. Harris, Dominic J. Dal Bello, Lynne A. Slivovsky Oct 2008

Work In Progress - Enhancing Student-Learning Through State-Of-The-Art Systems Level Design And Implementation, Albert A. Liddicoat, Jianbiao Pan, James G. Harris, Dominic J. Dal Bello, Lynne A. Slivovsky

Industrial and Manufacturing Engineering

The curriculum for undergraduate engineering programs is often partitioned into several courses that are taught in isolation followed by a single culminating senior design or capstone project experience. In the senior design class students being to synthesize the knowledge and skills that they acquired through the engineering curriculum. This paper presents lower and upper division course and curricular changes made to accommodate learning objectives that better prepare students for project-based learning. These learning experiences and skills include: systems level design, experience with state-of-the-art Computer Aided Design (CAD) tools, printed circuit board (PBC) design, design for manufacturability, electronics assembly, project management, …

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Work In Progress – Building The Survey Of Engineering Ethical Development (Seed) Instrument, Janel A. Sutkus, Donald D. Carpenter, Cynthia J. Finelli, Trevor S. Harding Oct 2008

Work In Progress – Building The Survey Of Engineering Ethical Development (Seed) Instrument, Janel A. Sutkus, Donald D. Carpenter, Cynthia J. Finelli, Trevor S. Harding

Materials Engineering

When developing surveys, researchers can readily identify the concepts they intend to study, but how do they create individual survey items that will most accurately measure those concepts? Here we describe the first year of a four-year NSF project in which the E3 Team (Exploring Ethical Decision Making in Engineering) prepared to develop a national survey of the curricular and cocurricular activities, events, and experiences affecting the ethical development of engineering undergraduates. As this survey is likely to be the most comprehensive assessment of ethical development - both in content and scope - ever administered to engineering undergraduates, it …

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The Psychology Of 'Ought', Trevor S. Harding Oct 2008

The Psychology Of 'Ought', Trevor S. Harding

Materials Engineering

As educators, we would like to believe that we can influence the ethical growth of our students. If we are to do this, it seems worthwhile to first understand what ethical decision-making is and how it happens. For millennia, ethical decision-making has fallen within the domain of philosophy. However, recent evidence suggests that the average person does not consider ethical dilemmas in the abstract. Instead, ethical decision-making appears to be a complex dance between an individual’s rational calculus of the ethical dilemma and their emotional response to the context of the dilemma. I will present an argument that in the …

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Optimization Of Top Polymer Gratings To Improve Gan Leds Light Transmission, Xiaomin Jin, Bei Zhang, Tao Dai, Wei Wei, Xiangning Kang, Guoyi Zhang, Simeon Trieu, Fei Wang Oct 2008

Optimization Of Top Polymer Gratings To Improve Gan Leds Light Transmission, Xiaomin Jin, Bei Zhang, Tao Dai, Wei Wei, Xiangning Kang, Guoyi Zhang, Simeon Trieu, Fei Wang

Electrical Engineering

We present a grating model of two-dimensional (2D) rigorous coupled wave analysis (RCWA) to study top diffraction gratings on light-emitting diodes (LEDs). We compare the integrated-transmission of the non-grating, rectangular-grating, and triangular-grating cases for the same grating period of 6 μm, and show that the triangular grating has the best performance. For the triangular grating with 6-μm period, the LED achieves the highest light transmission at 6-μm grating bottom width and 2.9-μm grating depth. Compared with the non-grating case, the optimized light transmission improvement is about 74.6%. The simulation agrees with the experimental data of the thin polymer grating encapsulated …

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Alternative Binder Carbide Tools For Machining Superalloys, Daniel J. Waldorf, Michael Stender, Scott Liu, Daniel Norgan Oct 2008

Alternative Binder Carbide Tools For Machining Superalloys, Daniel J. Waldorf, Michael Stender, Scott Liu, Daniel Norgan

Industrial and Manufacturing Engineering

This study examines the performance of a new class of wear-resistant but economical cutting tools produced by varying the binder composition of standard cemented carbide composites. By replacing some or all of the cobalt binder with rhenium and nickel-based superalloy, a stronger composite tool results, potentially capable of machining heat-resistant superalloys at significantly higher cutting speeds. Sample tools with alternative binder were produced and compared to standard tools bound with cobalt only. Turning experiments on Inconel 718 were run to evaluate wear resistance and tool life for several grades. The experimentation also examined the effects of varying the relative proportions …

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