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Mechanism Of Wear Protection Of Al-Alloys Using Xanes, Beibei Wang Jan 2009

Mechanism Of Wear Protection Of Al-Alloys Using Xanes, Beibei Wang

Material Science and Engineering Theses - Archive

The mechanism of wear protection of Al-Si alloys in wear tests using lubricants containing Zinc dialkyl-dithiophosphate (ZDDP), Dialkyl dithiophosphate (DDP) , Amine phosphates, Thiadiazole, Antimony 0, 0-dialkylphosphorodithioate (SbDDP) was studied. Using techniques such as XANES this study examined the tribological behavior of these compounds and the characteristics of the tribofilms formed by them. High frequency reciprocating rig (HFRB) tests were conducted with lubricant containing these five antiwear additives were compared in both base oil and fully formulated oil. The tribofilms formed were then analyzed by a variety of techniques such as Scanning electron microscopy of the film and the composition …

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Analysis Of Data Center Cooling Strategies And The Impact Of The Dynamic Thermal Management On The Data Center Efficiency, Veerendra Prakash Mulay Jan 2009

Analysis Of Data Center Cooling Strategies And The Impact Of The Dynamic Thermal Management On The Data Center Efficiency, Veerendra Prakash Mulay

Mechanical and Aerospace Engineering Dissertations - Archive

The power trend for Server systems continues to grow thereby making thermal management of Data centers a very challenging task. Although various configurations exist, the raised floor plenum with Computer Room Air Conditioners (CRACs) providing cold air is a popular operating strategy. The air cooling of data center however, may not address the situation where more energy is expended in cooling infrastructure than the thermal load of data center. Revised power trend projections by ASHRAE TC 9.9 predict heat load as high as 5000W per square feet of compute servers' equipment footprint by year 2010. These trend charts also indicate …

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Development Of A Quantum Dot Mediated Thermometry For Minimally Invasive Thermal Therapy, Willard L. Hanson Jan 2009

Development Of A Quantum Dot Mediated Thermometry For Minimally Invasive Thermal Therapy, Willard L. Hanson

Mechanical and Aerospace Engineering Dissertations - Archive

Thermally-related, minimally invasive therapies are designed to treat tumors while minimizing damage to the surrounding tissues. Adjacent tissues become susceptible to thermal injury to ensure the cancer is completely destroyed. Destroying tumor cells, while minimizing collateral damage to the surrounding tissue, requires the capacity to control and monitor tissue temperatures both spatially and temporally. Current devices measure the tumor's tissue temperature at a specific location leaving the majority unmonitored. A point-wise application can not substantiate complete tumor destruction. This type of surgery would be more effective if volumetric tissue temperature measurement were available. On this premise, the feasibility of a …

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Synergistic And Antagonistic Effect Of Sulfur-Based Additives On The Performance Of Greases With Zddp And Ptfe, Arunya Suresh Jan 2009

Synergistic And Antagonistic Effect Of Sulfur-Based Additives On The Performance Of Greases With Zddp And Ptfe, Arunya Suresh

Material Science and Engineering Theses - Archive

Lithium-base greases constitute about 50% of the grease market. The current trend is towards developing greases with longer working life and wider application flexibility. To address this concern, greases are blended with antiwear and extreme pressure (EP) additives that serve to reduce wear and increase the operating life of the machinery by creating a low strength, shearable film on the moving surfaces. In the current study, greases were developed to address the need for both performance as prescribed by the ASTM standards D2266 and D2596, respectively. The actual bearing conditions vary significantly with load, rpm and duration of test. These …

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Fabrication Of Plga Nanocomposite Using Two Photon Polymerization, Nikhil Narendra Kavadia Jan 2009

Fabrication Of Plga Nanocomposite Using Two Photon Polymerization, Nikhil Narendra Kavadia

Mechanical and Aerospace Engineering Theses - Archive

The demand of smaller size 3D structures in scale of several nanometers has significantly increased the need of development of new techniques for micro/nano fabrication. Applications of nanomaterial embedded true 3D micro/nano structures in the field of medicine, tissue engineering, scaffolding, drug delivery, antibacterial implants or catheters, modification of textiles and refinement of polymers has opened new areas of research for fabrication of nanocomposites embedded with engineering nanoparticles.A novel fabrication process called two photon polymerization (2PP) is employed for the fabrication of polymeric nanocomposites embedded with PLGA nanoparticles. An ultra short pulsed laser source is used to produce laser at …

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Dymore Finite Element Analysis Of The Paired Blade Tiltrotor Conceptual Design And A Comparable Conventional Tiltrotor Design, David Orion Braziel Jan 2009

Dymore Finite Element Analysis Of The Paired Blade Tiltrotor Conceptual Design And A Comparable Conventional Tiltrotor Design, David Orion Braziel

Mechanical and Aerospace Engineering Theses - Archive

Increasing the solidity of tiltrotors above that of current designs presents challenges associated with control system packaging and control couplings. The paired blade rotor concept addresses these issues by placing two blades that share a pitch link, located for acceptable control coupling, on each of three hub arms.Dymore finite element models of the paired blade rotor and a reference rotor of equal solidity with six evenly spaced blades were developed to identify any potential design flaws of the paired blade rotor associated with rotor frequency placement or control couplings. The finite element rotor models are documented, and the results of …

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Numerical Simulation Of Particle Adhesion Dynamics For Applications In Nanomedicine And Biosensing, Samar Shah Jan 2009

Numerical Simulation Of Particle Adhesion Dynamics For Applications In Nanomedicine And Biosensing, Samar Shah

Mechanical and Aerospace Engineering Theses - Archive

Multifunctional nanoparticles hold considerable promise as the next generation of medicine that allow for detection of early on-set of diseases and targeted therapy with minimal toxicity. To achieve targeted drug delivery, nanoparticles are usually functionalized with certain ligands (polymers) that bind specifically to a particular type of receptors on the endothelial cell surface, which are expressed exclusively during its diseased state. The ligand coated nanoparticles, loaded with drugs inside, transport in blood stream, and adhere to diseased cells via specific adhesion. However, this whole procedure becomes complicated due to simultaneous involvement of hydrodynamic force, adhesion force and Brownian force. In …

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Dynamic Stress From Transverse Impact On Flexural Beams, Joshua Ballard Jan 2009

Dynamic Stress From Transverse Impact On Flexural Beams, Joshua Ballard

Mechanical and Aerospace Engineering Theses - Archive

Accurate prediction of stress from impact would be very useful to an engineer in the design and analysis phases of a project. Currently one must resort to finite element analysis and experimentation, both of which have their negatives. Classical hand analysis methods such as the work-energy method overestimate the stress for a weight dropped onto the tip of a cantilevered beam. The goal of this project was to formulate analytical equations that were straightforward and easy to implement that would more accurately predict the dynamic stress in this scenario. Using the already derived equations from the work-energy method, a modification …

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Improving Receiver Station-Keeping In Aerial Refueling By Formulating Tanker Motion As Disturbance, Christopher Michael Elliott Jan 2009

Improving Receiver Station-Keeping In Aerial Refueling By Formulating Tanker Motion As Disturbance, Christopher Michael Elliott

Mechanical and Aerospace Engineering Theses - Archive

During aerial refueling operations, the receiver aircraft should hold position within a “refueling box” to maintain the boom-receptacle connection while the tanker aircraft flies in a racetrack maneuver. Prior research work shows, especially in turns, significant difficulty resides in meeting y-deviation requirements, i.e., to stay within the box in the lateral direction. This observation indicates tanker motion as “the biggest disturbance” in turn. The nonlinear equations of motion for the receiver aircraft used in this work are developed in terms of position and orientation states relative to the tanker. Linearization results in a set of equations with tanker motion clearly …

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On The Design Of A Biodegradable Poc-Ha Polymeric Cardiovascular Stent, Joonas Ilmari Ponkala Jan 2009

On The Design Of A Biodegradable Poc-Ha Polymeric Cardiovascular Stent, Joonas Ilmari Ponkala

Mechanical and Aerospace Engineering Theses - Archive

The current state of the art in coronary stent technology is mainly populated by metallic stents usually coated with certain drugs to increase biocompatibility, even though experimental biodegradable stents have appeared in the horizon. To design stents from biodegradable polymers one must accurately characterize their mechanical behavior for analysis and optimization.This manuscript presents the process for evaluating the material properties for biodegradable biocompatible POC-HA polymeric composite, techniques for developing the stent models for finite element analysis, and development of material models for finite element analysis. The developed material models were utilized in finite element analysis to evaluate the suitability of …

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Finite Element Analysis Of Forging, Aditya Ashok Battin Jan 2009

Finite Element Analysis Of Forging, Aditya Ashok Battin

Mechanical and Aerospace Engineering Theses - Archive

Numerical modeling and simulation of metal forming is very effective in saving production time, effort and economy and has thus gained prominence in many industries all over the world. In metal-forming finite element analysis, software like Deform, Qform, Forge, Simufact, Hyperform are used extensively for the forming analysis. Apart from having narrow applications, these softwares are expensive. The object of this study was to examine the robustness of general package softwares in regards to forging. Software such as Abaqus and Ansys LSDyna were used to simulate the forging process. The case examined was that of a circular metal disc restrained …

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Multi Objective Optimization Of Graphite Heat Spreader For Portable Systems Application, Arijit Banerjee Jan 2009

Multi Objective Optimization Of Graphite Heat Spreader For Portable Systems Application, Arijit Banerjee

Mechanical and Aerospace Engineering Theses - Archive

The advancement made in portable electronic systems has primarily been due to miniaturization of electronic systems. This in turn leads to an increase in power density which leads to higher temperatures and formation of hot spots. There is a temperature specification of system surfaces for human comfort (such as the surface close to a keyboard on laptops). Challenge in cooling portable devices is that there is not enough room to accommodate heat sinks. It is therefore important to have heat spreaders that can transfer the heat from critical devices to regions where cooling is available. Traditionally, copper has been the …

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A Numerical Study On The Dynamics Of Bubble Growth And Detachment From An Orifice, Sheshi Kumar Takkallapally Jan 2009

A Numerical Study On The Dynamics Of Bubble Growth And Detachment From An Orifice, Sheshi Kumar Takkallapally

Mechanical and Aerospace Engineering Theses - Archive

The study of bubble formation from an orifice finds numerous industrial applications which include bubble acoustics in ocean physics and chemical reactors. Numerical simulations have been performed to investigate the dynamics of bubble formation, growth and detachment from an orifice. The full transient Navier - Stokes equation is solved in a two-dimensional axi-symmetrical coordinate system. The surface tension implementation algorithm known as the Pressure Boundary Method (PBM) is used to model the surface tension. The robustness of PBM method on Two-Phase flows with different conditions has been shown. The results achieved by numerical simulations have been compared with the available …

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Heat Transfer Analysis Of A Pulse Detonation Engine, Neelima Kalidindi Jan 2009

Heat Transfer Analysis Of A Pulse Detonation Engine, Neelima Kalidindi

Mechanical and Aerospace Engineering Theses - Archive

A thermal analysis of the effect of sensible heat release on the walls of the detonation chamber for stoichiometric mixtures of hydrogen/air, octane/air and octane/oxygen was presented. The detonation tube was assumed to operate at 20 Hz and cooled by a water jacket to dissipate the heat from the walls which ensures the effective operation for a longer period. Wall material was assumed to be made of copper because of its high thermal conductivity.The study showed a slow temperature rise along the walls of the combustion chamber for multiple pulses. It can be concluded that due to the space-time averaging …

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Thermal Conduction Equations For A Medium With An Inclusion Using Galerkin Method, Thiagarajan Sivalingam Jan 2009

Thermal Conduction Equations For A Medium With An Inclusion Using Galerkin Method, Thiagarajan Sivalingam

Mechanical and Aerospace Engineering Theses - Archive

The Galerkin method is used to semi-analytically solve the heat conduction equation in non-homogeneous materials. The problem under deliberation is a square plate with a circular inclusion having different thermal conductivities. A generalized procedure that involves the Galerkin method and formulation of the final solution in terms of the procured base functions is adopted. The Galerkin method basically involves expressing the given boundary value problem in terms of a standard mathematical relation, generating a set of continuous base functions, formulating the matrix equation, and determining the solution.For the non-homogeneous material, a set of base functions for the plate and inclusion …

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Corrosion And Leaching Study Of Low Copper (I) Oxide Paints For Antifouling Application, Hansika Parekh Jan 2009

Corrosion And Leaching Study Of Low Copper (I) Oxide Paints For Antifouling Application, Hansika Parekh

Material Science and Engineering Theses - Archive

Global environmental concern/economy challenges necessitate innovation of AFP's with novel additives offering improved corrosion protection, and biofouling resistance. Dispersing large proportions (40-70%) of Cu/Cu2O in paints although inexpensive produces excessive leaching & heavy accumulation of copper in marine. This study aims at formulating AFP's with reduced Cu2O levels along with novel additives, targeting controlled copper release around 15 ug/cm2/day. In the present study several formulations were prepared using Viscoplex (PAMA in mineral oil), Ionomer ED-SPAN and CuDDP. Substitute ocean water was prepared to simulate marine environmental conditions and perform leaching studies of different formulations. A variety of preliminary elimination tests …

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Structural Optimization Using Ansys Classic And Radial Basis Function Based Response Surface Models, Vijay Krishna Jan 2009

Structural Optimization Using Ansys Classic And Radial Basis Function Based Response Surface Models, Vijay Krishna

Mechanical and Aerospace Engineering Theses - Archive

This thesis describes a methodology to develop an effective and simple structural optimization method using Response Surfaces. It also further demonstrates how these Response Surfaces can then be utilized for further Multi Objective Optimization. The true or exact responses were calculated using Ansys Classic while the codes for the training and simulation of Response Surface is pro-grammed in Matlab. Initially we used a Halton sequence to generate a DOE of the design variables. Then we used Ansys Classic to generate the exact responses. Once the responses were imported the Response Surface are generated using a RBF approximation model. This RBF …

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Electrowetting On Dielectric (Ewod) Digital Microfluidics For Electronic Hotspot Cooling, Govindraj Shreyas Bindiganavale Jan 2009

Electrowetting On Dielectric (Ewod) Digital Microfluidics For Electronic Hotspot Cooling, Govindraj Shreyas Bindiganavale

Mechanical and Aerospace Engineering Theses - Archive

Electronics cooling was a field dominated by bulky and heavy heat sinks, heat pipes and fans for decades. Lately, the size of the electronic components has decreased to a substantial extent with an increase in performance. This has fuelled a need for smaller, lighter, yet efficient cooling systems. A lot of research has been done to build innovative cooling solutions which satisfied most of the requirements as stated above. Some of them still have limitations like use of the right coolants and design challenges. Digital microfluidics is one field which can solve all these issues by providing a simple, reliable …

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A Unified Analysis Of Stiffener Reinforced Composite Beams With Arbitrary Cross-Section, Gianfranco Rios Jan 2009

A Unified Analysis Of Stiffener Reinforced Composite Beams With Arbitrary Cross-Section, Gianfranco Rios

Mechanical and Aerospace Engineering Dissertations - Archive

A number of methods are available to analyze the laminated composite beams using smear property of laminate stiffness ignoring unsymmetrical behavior of laminates. Some include their effect of laminate but did not include the unsymmetrical effect of the cross-section of the beam. On the other hand, using finite element method to analyze the beam is dependent on the structural configurations including the laminate lay-up sequence. An analytical method was developed from lamination theory in order to study the structural response of composite laminated beams. The present method is capable of predicting the axial and bending stiffnesses, the centroid location, and …

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A Generic Methodology For Flight Test And Safety Evaluation At Conceptual Design, Amit R. Oza Jan 2009

A Generic Methodology For Flight Test And Safety Evaluation At Conceptual Design, Amit R. Oza

Mechanical and Aerospace Engineering Theses - Archive

The current research is dedicated to the application of a simulation suite that emulates flight testing and is applicable to the aircraft conceptual and preliminary design environment. The configuration concept available for study is an unmodified Cessna Citation X. The research goal is to arrive at a systematic process that reduces aircraft design risk while creating transparency for the manager and engineer during product life-cycle simulation. When integrating the discipline of flight test emulation into the development methodology, the objective is to complement and enrich the design simulation through a correct representation of flight safety relevant disciplines like aircraft certification, …

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Solar Selective Optical Coating Made With Metal Nanopaticles For Photovoltaic Thermal Applications, Xin Wang Jan 2009

Solar Selective Optical Coating Made With Metal Nanopaticles For Photovoltaic Thermal Applications, Xin Wang

Material Science and Engineering Theses - Archive

The goal of this research is to fabricate solar selective reflector with suitable optical properties and high thermal and chemical stability for using in the photovoltaic thermal window. While the reflector allows some transmittance in visible spectrum, the mid/far infrared light needs to be reflected back into the window minimizing the IR radiation loss. Nickel/alumina composite was proposed as the solar selective reflector. This thesis consists of two parts - one part concerning the fabrication and characterization of solar selective reflector and another dealing with an optical modeling to simulate the optical properties of the solar selective reflector. The alumina …

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High Temperature Microporous Coatings: The Effects Of Wetting And Wicking On Nucleate Boiling And Chf, Ross Evan Pivovar Jan 2009

High Temperature Microporous Coatings: The Effects Of Wetting And Wicking On Nucleate Boiling And Chf, Ross Evan Pivovar

Mechanical and Aerospace Engineering Theses - Archive

Porous coatings have long been a method to enhance boiling heat transfer. Previous researchers have thoroughly explained most of the physics behind the enhancement, but some holes still exist. Correlations, setup to predict nucleate boiling, are often only accurate in specific scenarios. CHF correlations that take into account wettability do not consider microstructure changes that decrease contact angle, but do not enhance CHF. A solution to these problems is presented via the wicking and wetting of liquid on a porous surface. CHF is found to be enhanced with increases in wicking speeds and flow rate. Wetting, measured by apparent contact …

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Price Discovery Of Credit Risk, Yibing Du Jan 2009

Price Discovery Of Credit Risk, Yibing Du

Finance and Real Estate Dissertations - Archive

This study investigates financial markets' price discovery for credit risk across the stock, bond, and credit derivatives markets. This study also examined what factors affect financial market's price discovery for credit risk. Four factors are studied: liquidity, transaction cost, credit ratings and maturities. Using weekly equity, bond and credit default swap market data from January 2000 to October 2007, it is found that stock market and bond market, credit derivative market and bond market are cointegrated for long term credit risk price discovery. In short term, both stock market and credit derivatives market lead the bond market for credit risk …

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Is There Predictive Value In The Words Managers Use? A Key Word Analysis Of The Annual Report's Management Discussion And Analysis., Gene Brooks Elrod Jan 2009

Is There Predictive Value In The Words Managers Use? A Key Word Analysis Of The Annual Report's Management Discussion And Analysis., Gene Brooks Elrod

Accounting Dissertations - Archive

This study examines whether managers use linguistic style (i.e. optimistic and pessimistic tone) in the Management Discussion and Analysis (MD&A) section of the annual report to the SEC, Form 10-K, to provide information about expected future firm performance to the investors and whether market prices (investors) respond to these disclosures. Textual analysis software, Diction 5.0, is used to measure optimistic and pessimistic tone of MD&A for the year 2002 for 423 manufacturing firms. Previous research similar to this study found evidence that managers use linguistic style or tone to reveal information to financial statement users through their textual releases in …

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Impact Of The Advancement Via Individual Determination (Avid) Program On Closing The Academic Achievement Gap, Charlotte S. Ford Jan 2009

Impact Of The Advancement Via Individual Determination (Avid) Program On Closing The Academic Achievement Gap, Charlotte S. Ford

Public Affairs Dissertations - Archive

There is disparity in the quality of school experiences encountered by students of different races, languages, social classes, and communities. There are also systemic issues that affect the quality of education received by students attending schools primarily comprised of students from the lower socioeconomic status and ethnic minorities. Students of color and students from low socioeconomic backgrounds consistently earn lower grades and lower test scores than their peers. Despite many education reform efforts in the 1980s and 1990s, the academic achievement gap continues to persist.AVID program was evaluated as an academic intervention program geared toward closing the academic achievement gap. …

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More Than Money: Higher Education Decisions Of Low-Income And Minority Students, Tiffany Gurley-Alloway Jan 2009

More Than Money: Higher Education Decisions Of Low-Income And Minority Students, Tiffany Gurley-Alloway

Public Affairs Dissertations - Archive

A gap persists in K-12 academic achievement, high school persistence, college attendance, and educational attainment by income level and race/ethnicity. Issues of race and ethnicity in education are often intertwined with those of economic status because African Americans and Latinos are more likely to live in poverty and have lower median household incomes than are Whites in US. Much of the literature regarding the achievement gap focuses on barriers faced by low-income and minority students; two barriers in particular are low student motivation and inadequate academic preparation. In addition to these individual level barriers, schools as institutions perpetuate and reward …

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The Relationship Between Management Diversity And Supplier Diversity Program Development: A Supplier Diversity Professional Perspective, Marilyn L. King Jan 2009

The Relationship Between Management Diversity And Supplier Diversity Program Development: A Supplier Diversity Professional Perspective, Marilyn L. King

Public Affairs Dissertations - Archive

Companies that supply the Federal government with goods and services are required by law to have a supplier diversity program/initiative. They are also required to appoint a supplier diversity professional to manage the program. Programs are audited by the Small Business Administration to determine due diligence efforts to achieve the mandated annual spend, education, and development requirements from the Veterans Administration for small businesses. Supplier diversity programs typically begin at the token level and can usually be developed to a world class level if the initiatives are strategically integrated in the corporation's supply chain and supported by senior management. For …

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Impact Of The Advancement Via Individual Determination (Avid) Program On Closing The Academic Achievement Gap, Charlotte S. Ford Jan 2009

Impact Of The Advancement Via Individual Determination (Avid) Program On Closing The Academic Achievement Gap, Charlotte S. Ford

Public Affairs Dissertations - Archive

There is disparity in the quality of school experiences encountered by students of different races, languages, social classes, and communities. There are also systemic issues that affect the quality of education received by students attending schools primarily comprised of students from the lower socioeconomic status and ethnic minorities. Students of color and students from low socioeconomic backgrounds consistently earn lower grades and lower test scores than their peers. Despite many education reform efforts in the 1980s and 1990s, the academic achievement gap continues to persist.AVID program was evaluated as an academic intervention program geared toward closing the academic achievement gap. …

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The Relationship Between Management Diversity And Supplier Diversity Program Development: A Supplier Diversity Professional Perspective, Marilyn L. King Jan 2009

The Relationship Between Management Diversity And Supplier Diversity Program Development: A Supplier Diversity Professional Perspective, Marilyn L. King

Public Affairs Dissertations - Archive

Companies that supply the Federal government with goods and services are required by law to have a supplier diversity program/initiative. They are also required to appoint a supplier diversity professional to manage the program. Programs are audited by the Small Business Administration to determine due diligence efforts to achieve the mandated annual spend, education, and development requirements from the Veterans Administration for small businesses. Supplier diversity programs typically begin at the token level and can usually be developed to a world class level if the initiatives are strategically integrated in the corporation's supply chain and supported by senior management. For …

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More Than Money: Higher Education Decisions Of Low-Income And Minority Students, Tiffany Gurley-Alloway Jan 2009

More Than Money: Higher Education Decisions Of Low-Income And Minority Students, Tiffany Gurley-Alloway

Public Affairs Dissertations - Archive

A gap persists in K-12 academic achievement, high school persistence, college attendance, and educational attainment by income level and race/ethnicity. Issues of race and ethnicity in education are often intertwined with those of economic status because African Americans and Latinos are more likely to live in poverty and have lower median household incomes than are Whites in US. Much of the literature regarding the achievement gap focuses on barriers faced by low-income and minority students; two barriers in particular are low student motivation and inadequate academic preparation. In addition to these individual level barriers, schools as institutions perpetuate and reward …

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