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University of Arkansas, Fayetteville

2012

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Articles 1 - 30 of 105

Full-Text Articles in Physical Sciences and Mathematics

Walmart's Sustainability Journey: Andy Ruben And The Design Of Organizational Structures And Systems (B), David G. Hyatt, Andrew Spicer Dec 2012

Walmart's Sustainability Journey: Andy Ruben And The Design Of Organizational Structures And Systems (B), David G. Hyatt, Andrew Spicer

Wal-Mart Sustainability Case Project

The case “Andy Ruben and the Design of Strategic Goals and Processes” flows from the previous discussion, by moving from the development of an ambitious vision to the challenges of adopting strategic policies and processes to reach those aspirations in practice. This case puts students into the role of Andy Ruben, Walmart’s first Vice-President for Sustainability , asking them to make concrete decisions about what should be done, in what order, and by what process if they were to implement an ambitious corporate sustainability strategy. In the case, Ruben confronts specific choices about how to define the responsibilities of the …


Walmart's Sustainability Journey: Lee Scott's Founding Vision, Andrew Spicer, Laura Lambdin Dec 2012

Walmart's Sustainability Journey: Lee Scott's Founding Vision, Andrew Spicer, Laura Lambdin

Wal-Mart Sustainability Case Project

The first case—“Lee Scott’s Founding Vision”—takes the perspective from the apex of the organization as Walmart’s CEO, Lee Scott, develops and articulates his vision of what Walmart hopes to achieve by pursuing an aggressive sustainability strategy. This case explores the pressures that led Scott to announce the company’s ambitious sustainability goals: achieving zero waste, 100% renewable energy, and selling sustainable products. It also explores the choices made when defining and communicating the scope of the strategy, particularly through an in-depth analysis of his announcement of Walmart’s new goals in his October 2005, “Twenty-First Century Leadership” speech.


Walmart's Sustainability Journey: Andy Ruben And The Design Of Organizaional Structures And Systems (A), Andrew Spicer, Laura Lambdin Dec 2012

Walmart's Sustainability Journey: Andy Ruben And The Design Of Organizaional Structures And Systems (A), Andrew Spicer, Laura Lambdin

Wal-Mart Sustainability Case Project

The case “Andy Ruben and the Design of Strategic Goals and Processes” flows from the previous discussion, by moving from the development of an ambitious vision to the challenges of adopting strategic policies and processes to reach those aspirations in practice. This case puts students into the role of Andy Ruben, Walmart’s first Vice-President for Sustainability , asking them to make concrete decisions about what should be done, in what order, and by what process if they were to implement an ambitious corporate sustainability strategy. In the case, Ruben confronts specific choices about how to define the responsibilities of the …


Consumers And Sustainability At Walmart: A Student's Perspective, Kealy Carter, Satish Jayachandran Dec 2012

Consumers And Sustainability At Walmart: A Student's Perspective, Kealy Carter, Satish Jayachandran

Wal-Mart Sustainability Case Project

To further encourage students to analyze initial goals in comparison with outcomes over time, we have developed a consumer-oriented case—“Consumers and Sustainability at Walmart: A Student’s Perspective”—that moves beyond the perspective of internal Walmart participants to explores issues of sustainability from the point of view of a typical Walmart shopper. In this case, we examine the experience of a fictional student shopper who goes to Walmart and wants to buy sustainable products, which helps raise questions for students about what Walmart’s actions mean to them as consumers, citizens as well as business professionals. The case also asks students to evaluate …


Walmart's Sustainability Journey: Defining Sustainable Products (B), David G. Hyatt, Andrew Spicer Dec 2012

Walmart's Sustainability Journey: Defining Sustainable Products (B), David G. Hyatt, Andrew Spicer

Wal-Mart Sustainability Case Project

In “Defining Sustainable Products (A),” we examine Walmart’s search for a systemic solution to define a sustainable product precisely. In this case, Matt Kistler, who succeeded Andy Ruben as the company sustainability leader in 2007, knows that the company is lagging behind on its espoused goal of selling sustainable products. The case asks students step into Kistler’s shoes as he leads Walmart’s sustainability office through a systematic review of the different models and frameworks available for measuring the sustainability of products presently in use. Eventually, the students face a decision about what Walmart should do to make systemic progress with …


Walmart's Sustainability Journey: Defining Sustainable Products (A), David G. Hyatt, Andrew Spicer Dec 2012

Walmart's Sustainability Journey: Defining Sustainable Products (A), David G. Hyatt, Andrew Spicer

Wal-Mart Sustainability Case Project

In “Defining Sustainable Products (A),” we examine Walmart’s search for a systemic solution to define a sustainable product precisely. In this case, Matt Kistler, who succeeded Andy Ruben as the company sustainability leader in 2007, knows that the company is lagging behind on its espoused goal of selling sustainable products. The case asks students step into Kistler’s shoes as he leads Walmart’s sustainability office through a systematic review of the different models and frameworks available for measuring the sustainability of products presently in use. Eventually, the students face a decision about what Walmart should do to make systemic progress with …


Walmart's Sustainability Journey: Peter Redmond And The Search For Sustainable Seafood, David G. Hyatt Dec 2012

Walmart's Sustainability Journey: Peter Redmond And The Search For Sustainable Seafood, David G. Hyatt

Wal-Mart Sustainability Case Project

In “Peter Redmond and the Search for Sustainable Seafood,” students examine the responses of Peter Redmond, Vice President and Divisional Merchandise Manager of Deli and Seafood, to organizational pressures to make seafood more sustainable at Walmart.


The Design And Implementation Of A Mobile Game Engine For The Android Platform, Jon Hammer Dec 2012

The Design And Implementation Of A Mobile Game Engine For The Android Platform, Jon Hammer

Computer Science and Computer Engineering Undergraduate Honors Theses

In this thesis, a two-dimensional game engine is proposed for the Android mobile platform that facilitates rapid development of those games by individual developers or hobbyists. The essential elements of game design are presented so as to introduce the reader to the concepts that are crucial for comprehension of the paper. A brief overview of the Android Operating System is also included for those unfamiliar with it. Three primary design goals are identified, and a prototype solution is described in detail. The prototype is then evaluated against those design goals to see how well it accomplishes each task. The results …


New Applications Of Mass Spectrometry For Drug And Lipid Analysis, Elizabeth Lauren Emerson Dec 2012

New Applications Of Mass Spectrometry For Drug And Lipid Analysis, Elizabeth Lauren Emerson

Graduate Theses and Dissertations

Mass spectrometry is an important tool used in many different disciplines and settings that include forensics, drug discovery, environmental analysis, and proteomics. Gas chromatography - mass spectrometry (GC-MS) and matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI - TOF MS) are two of the most important instruments used for analysis of compounds. Chapters 1 and 2 of this discussion use GC-MS for the investigation of synthetic cannabinoids in `K2' incense products and the detection of metabolites in urine samples from individuals suspected of consuming these mixtures. Analytical standards were synthesized and used for identification and confirmation of structures. Detection of …


Refractive Index Chemical Sensing With Noble Metal Nanoparticles, Phillip Blake Dec 2012

Refractive Index Chemical Sensing With Noble Metal Nanoparticles, Phillip Blake

Graduate Theses and Dissertations

Chemical sensing is a key component in modern society, especially in engineering applications. Because of their widespread impact, improvements to chemical sensors are a significant area of research. One class of sensors, plasmonic sensors, is being heavily researched because of their ability to detect low levels of analyte in near real time without destroying the analyte. This work studies a new class of plasmonic sensor that utilizes diffractive coupling to improve sensor performance. Specifically, this work outlines the first study of diffractive coupling sensors with typical nanoparticle shapes. Sensitivity of this new class of sensor is directly compared to typical …


Long-Term Effects Of Rice Rotation, Tillage, And Fertility On Near-Surface Soil Carbon And Nitrogen Cycling, Jill Marie Motschenbacher Dec 2012

Long-Term Effects Of Rice Rotation, Tillage, And Fertility On Near-Surface Soil Carbon And Nitrogen Cycling, Jill Marie Motschenbacher

Graduate Theses and Dissertations

Rice (Oryza sativa L.)-based cropping systems are different from other row crops due to the flood-irrigation scheme used from about one month after planting to a few weeks prior to harvest. The frequent cycling between anaerobic (i.e., flooding during the growing season) and aerobic (i.e., generally, the remainder of the year) conditions can influence the rate of soil organic matter (SOM) decomposition, which can greatly influence carbon (C) and nitrogen (N) storage and sequestration in the soil over time. Therefore, a study was conducted on a silt-loam soil (fine, smectitic, thermic, Typic Albaqualf) at the Rice Research and Extension Center …


Evaluation Of The Effects Of Absorption Field Product Architecture Type On Effluent Dispersal And Soil Chemical Properties In A Profile-Limited Soil, Nina J.M. Prater Dec 2012

Evaluation Of The Effects Of Absorption Field Product Architecture Type On Effluent Dispersal And Soil Chemical Properties In A Profile-Limited Soil, Nina J.M. Prater

Graduate Theses and Dissertations

On-site wastewater treatment systems (OWTSs) are commonly used by households in areas of low population density to treat household wastewater and recycle it back to the environment. The traditional absorption field product used in OWTSs is a pipe-and-gravel architecture type, which has been used for decades and is the basis for most design regulations. However, new products of differing architecture types including chambers, polystyrene-aggregate, pipe-and-tire-chip, and gravel-less-pipe systems have recently become available. A three-year field study was conducted in Bethel Heights, AR to assess the performance of several newer products and to compare different architecture types to the traditional pipe-and-gravel …


Prehistoric Human Ecodynamics In The Rub Al-Khali Desert: Results Of Remote Sensing And Excavations In Dubai, United Arab Emirates, Jason T. Herrmann Dec 2012

Prehistoric Human Ecodynamics In The Rub Al-Khali Desert: Results Of Remote Sensing And Excavations In Dubai, United Arab Emirates, Jason T. Herrmann

Graduate Theses and Dissertations

Archaeological investigations in the Emirate of Dubai, UAE conducted by the Dubai Department of Archaeology and the University of Arkansas demonstrate that the desert inland of the Oman Peninsula was occupied not only during the Arabian Neolithic (8000-4400 BC), when the region experienced a moist period referred to as the Holocene Climatic Optimum (HCO), but also during the more arid millennia following the decline of the HCO into the Christian Era. During this period, desert settlement clustered near a band of oases, in contrast to the more widespread spatial distribution of remains of nomadic pastoralists from the Neolithic. Excavations at …


Stratigraphic Variations In The Carboniferous Section Across The Arkansas-Oklahoma State Line Arch, Tyler Dean Engelhardt Dec 2012

Stratigraphic Variations In The Carboniferous Section Across The Arkansas-Oklahoma State Line Arch, Tyler Dean Engelhardt

Graduate Theses and Dissertations

The State Line Arch is represented by a structural high that trends through the study area in a loose alignment with the Arkansas-Oklahoma state line. Evidence of the arch extending further to the north includes a structural high and stratigraphic variation at an outcrop on Highway 59 near Evansville Mountain in Crawford County, Arkansas. The exact timing of the formation of the arch remains undetermined, but upper Devonian thinning at the top of the arch indicates the structure is pre-Mississippian. The reason for the development of the arch is poorly understood, but evidence linking Mississippian-aged Waulsortian mounds to Precambrian Spavinaw …


Assessing The Impacts Of Surface Water Removal For Use In Natural Gas Extraction On A Watershed Level, Carrie Ann Davis Dec 2012

Assessing The Impacts Of Surface Water Removal For Use In Natural Gas Extraction On A Watershed Level, Carrie Ann Davis

Graduate Theses and Dissertations

In this study, the Soil and Water Assessment Test (SWAT) was used as a tool to predict whether diffuse water removal from the Cadron Creek watershed for use with natural gas development would have an impact on downstream flow within the watershed. Cadron Creek watershed expands across four counties within Arkansas and is located in the Fayetteville Shale Gas region. This region is experiencing significant growth in natural gas development. Successful development of shale gas depends on the identification of what water supplies are available for production without interfering with community and environmental needs. The SWAT model used to evaluate …


An Economic Alternative To The C Chart, Ryan William Black Dec 2012

An Economic Alternative To The C Chart, Ryan William Black

Graduate Theses and Dissertations

Because the probability of Type I error is not evenly distributed beyond upper and lower three-sigma limits the c chart is theoretically inappropriate for a monitor of Poisson distributed phenomena. Furthermore, the normal approximation to the Poisson is of little use when c is small. These practical and theoretical concerns should motivate the computation of true error rates associated with individuals control assuming the Poisson distribution. An economic alternative to the c chart is described as a statistical model of upward shift from c0 to c1 and the two charts are compared in theory. For a range of c chart …


Design Of A Pretreatment And Enzymatic Saccharification Scheme Of Understory From Managed Pine Forest For A Biochemical-Refinery Platform: The Example Of The Sweetgum Tree, Angele Djioleu Dec 2012

Design Of A Pretreatment And Enzymatic Saccharification Scheme Of Understory From Managed Pine Forest For A Biochemical-Refinery Platform: The Example Of The Sweetgum Tree, Angele Djioleu

Graduate Theses and Dissertations

The possibility of using sweetgum from southern pine dominated forests as a biobased refinery feedstock was investigated. First, a baseline hydrolysis scheme for sweetgum wood and bark was designed. Sweetgum wood and bark were pretreated with 0.98% (v/v) sulfuric acid at 140°C for 30, 40, 50, 60 or 70 min and at 160°C for 30, 40, 50 or 60 min. The water insoluble solid (WIS) fraction was hydrolyzed with a cellulase enzyme cocktail. Results showed that maximum xylose and glucose yields from the wood were 82 and 86%, respectively. Similarly, the respective maximum yields of xylose and glucose from the …


A Watershed Scale Evaluation Of Selected Second Generation Biofeedstocks On Water Quality, Gurdeep Singh Dec 2012

A Watershed Scale Evaluation Of Selected Second Generation Biofeedstocks On Water Quality, Gurdeep Singh

Graduate Theses and Dissertations

This study compares a novel simulation approach to the conventional Soil and Water Assessment Tool (SWAT) modeler's approach for targeting biofuel crop production on marginal lands. In conventional SWAT modeling approach, non-spatial definition of hydrological response units (HRUs) results in the simulation of biofuel crops on both marginal and non-marginal land. This study provides an alternative approach in which a marginal-land raster was integrated into the land use and land cover (LULC) raster in such a way that the land uses were divided into marginal and non-marginal components. This modified LULC was used for model setup which resulted in marginal …


Penetration Forces For Subsurface Regolith Probes, Ahmed Elshafie Dec 2012

Penetration Forces For Subsurface Regolith Probes, Ahmed Elshafie

Graduate Theses and Dissertations

Investigating planetary bodies using penetrometers can provide detailed information about its history and evolution. An estimation of subsurface density and porosity can be made from the shape of the penetration curve. Using penetrometers mounted on planetary platforms could be challenging due to the uncertainty of the subsurface composition and since the maximum allowed force for penetration is the weight of the lander or rover on the surface. Estimation of penetration forces can provide a reliable constraint on the maximum reachable depth without endangering the whole mission. Therefore, knowledge of the required penetration force to specific depths can be helpful in …


On The Representation Of Inverse Semigroups By Difunctional Relations, Nathan Bloomfield Dec 2012

On The Representation Of Inverse Semigroups By Difunctional Relations, Nathan Bloomfield

Graduate Theses and Dissertations

A semigroup S is called inverse if for each s in S, there exists a unique t in S such that sts = s and tst = t. A relation σ contained in X x Y is called full if for all x in X and y in Y there exist x' in X and y' in Y such that (x, y') and (x', y) are in σ, and is called difunctional if σ satisfies the equation σ σ-1 σ = σ. Inverse semigroups were introduced by Wagner and Preston in 1952 and 1954, respectively, and difunctional relations were …


Plasmonic And Photonic Designs For Light Trapping In Thin Film Solar Cells, Liming Ji Dec 2012

Plasmonic And Photonic Designs For Light Trapping In Thin Film Solar Cells, Liming Ji

Graduate Theses and Dissertations

Thin film solar cells are promising to realize cheap solar energy. Compared to conventional wafer cells, they can reduce the use of semiconductor material by 90%. The efficiency of thin film solar cells, however, is limited due to insufficient light absorption. Sufficient light absorption at the bandgap of semiconductor requires a light path more than 10x the thickness of the semiconductor. Advanced designs for light trapping are necessary for solar cells to absorb sufficient light within a limited volume of semiconductor. The goal is to convert the incident light into a trapped mode in the semiconductor layer.

In this dissertation, …


Investigating The Sensitivity Of Goodness-Of-Fit Indices To Detect Measurement Invariance In The Bifactor Model, Jam Khojasteh Dec 2012

Investigating The Sensitivity Of Goodness-Of-Fit Indices To Detect Measurement Invariance In The Bifactor Model, Jam Khojasteh

Graduate Theses and Dissertations

A Monte Carlo simulation study was conducted to evaluate the sensitivities of five commonly used goodness-of-fit indices to detect metric invariance properties of the bifactor model. The fit indices that performed the best in terms of power were Gamma and Mc. In addition, Gamma, Mc, CFI, and RMSEA all held Type I error to a minimum. However, only Gamma and CFI are recommended to use in the bifactor model because the other GOF indices have cutoff values that are too large. For Gamma and CFI values of -.026 to -.045 and -.004 to -.009, respectively indicate a lack of metric …


Habitat Modeling Of Three Endemic Crayfish Species In The Black River Drainage Of Missouri And Arkansas: Factors Affecting Distribution And Abundance, Matthew Stephen Nolen Dec 2012

Habitat Modeling Of Three Endemic Crayfish Species In The Black River Drainage Of Missouri And Arkansas: Factors Affecting Distribution And Abundance, Matthew Stephen Nolen

Graduate Theses and Dissertations

The Ozark faunal region of Missouri and Arkansas harbors a high level of aquatic biological diversity, especially in regards to endemic crayfish. Orconectes eupunctus, Orconectes marchandi, and Cambarus hubbsi are three such endemics that are threatened by a limited natural distribution and the invasions of Orconectes neglectus. I sought to determine how natural and anthropogenic factors influence these three species across multiple spatial scales. Local and landscape data were used in decision tree analyses (CART) to determine their influence effect on presence/absence and density of the three species. Predictive models were validated using k-fold cross validation. O. eupunctus presence was …


Diagenesis And Reservoir Characterization Of The Pennsylvanian Middle Atoka Formation, Sebastian And Logan Counties, West-Central Arkansas, Elvis Chekwube Bello Dec 2012

Diagenesis And Reservoir Characterization Of The Pennsylvanian Middle Atoka Formation, Sebastian And Logan Counties, West-Central Arkansas, Elvis Chekwube Bello

Graduate Theses and Dissertations

The Middle Atoka Formation evolved from a stable passive margin during the early Pennsylvanian time to a rapidly subsiding basin, with the sedimentary fill thickening greatly southward during the middle Pennsylvanian time. The basin dips in north-south direction. An east-west anticlines and synclines were observed.

The purpose of this study is to establish the stratigraphic units, reservoir geometry and distribution, and infer the depositional environments and reservoir quality. Well correlation and petrographic studies are used to achieve the goals.

Sandstone Point Count method was used. The Point Counts was divided into five categories. They include the framework grains (quartz, feldspar, …


Pulse Sharpening Effects Of Thin Film Ferroelectric Transmission Lines, Robert J. Sleezer Dec 2012

Pulse Sharpening Effects Of Thin Film Ferroelectric Transmission Lines, Robert J. Sleezer

Graduate Theses and Dissertations

Advances in material science have resulted in the development of electrically nonlinear high dielectric thin film ferroelectrics, which have led to new opportunities for the creation of novel devices. This dissertation investigated one such device: a low voltage nonlinear transmission line (NLTL). A finite element simulation of ferroelectric transmission lines showed that NLTLs are capable of creating shockwaves. Additionally, if the losses are kept sufficiently low, it was shown that voltage gain should be possible. Furthermore, a method of accounting for material dispersion was developed. Results from simulations including material dispersion showed that temporal solitons might be possible from a …


Exploring The Surface Liquid And Lake Regions Of Titan With Laboratory Experimentation And Cassini Spacecraft Data, Felix Casimir Wasiak Dec 2012

Exploring The Surface Liquid And Lake Regions Of Titan With Laboratory Experimentation And Cassini Spacecraft Data, Felix Casimir Wasiak

Graduate Theses and Dissertations

The surface liquids and lake regions of Titan are studied utilizing three unique techniques, the results of which are reported in this dissertation. The development of a facility to simulate the surface conditions of Titan, and to conduct experiments on samples within that facility, brings an understanding of Titan's surface not possible through observation and modeling alone. The properties of this facility are presented, including conceptual methodology, design, implementation, performance, and experimental results. The facility, the main component of which is a simulation chamber, allows for Titan temperatures of 90 - 94 K and a 1.5 bar N2 atmosphere. The …


Effects Of Testing Time On Anaerobic Toxicity Assessment, Omolola Atinuke Akintomide Aug 2012

Effects Of Testing Time On Anaerobic Toxicity Assessment, Omolola Atinuke Akintomide

Graduate Theses and Dissertations

Anaerobic digestion has been widely used for wastewater treatment for decades. Several Anaerobic Toxicity tests have been developed to screen wastewater for toxicity and assess the treatability of such toxicants. However, past research and reviews on Biochemical Methane Potential (BMP) test and Anaerobic Toxicity Assay (ATA) were considered in this study.

The experimental tests included ammonium-nitrogen and sodium chloride toxicity tests with varied concentration and solid retention time. These tests were designed to demonstrate the impact of ammonia- nitrogen and sodium chloride on the biological degradation process. The anaerobic test set-up includes bench-scale test reactors and respirometers used for measuring …


Magnitude And Frequency Of Floods For Rural, Unregulated Streams Of Tennessee By L-Moments Method, Hongxiang Yan Aug 2012

Magnitude And Frequency Of Floods For Rural, Unregulated Streams Of Tennessee By L-Moments Method, Hongxiang Yan

Graduate Theses and Dissertations

This study presents a regional frequency analysis of Tennessee using the well-known Bulletin-17B method standardly used in the United States and the relatively new and developing L-Moments methods. Flood frequency characteristics were defined for 416 gaging stations located primarily in rural and lightly developed areas of Tennessee. All the gaging stations have 10 or more years of record through 2006. Using the L-Moments method, the generalized extreme value distribution was identified as the most robust distribution for each of four hydrologic areas. Multiple regression equations were also calculated for estimating the flood frequency of ungaged, unregulated, rural streams in each …


The Development Of A High Performance Concrete To Store Thermal Energy For Concentrating Solar Power Plants, Emerson Esmond John Aug 2012

The Development Of A High Performance Concrete To Store Thermal Energy For Concentrating Solar Power Plants, Emerson Esmond John

Graduate Theses and Dissertations

In recent years, due to rising energy costs as well as an increased awareness of the environmental effects of greenhouse gas emissions produced through traditional forms of energy production, there is great interest in developing alternative sources of energy. One of the most viable alternative energy sources is solar energy. In particular, concentrating solar power (CSP) technologies have been identified as an option for meeting utility needs in the U.S. Southwest. These systems are required to produce electricity not only during periods of high solar radiation but also during times of reduced radiation due to cloud cover, and even extend …


Locating And Protecting Facilities Subject To Random Disruptions And Attacks, Hugh Medal Aug 2012

Locating And Protecting Facilities Subject To Random Disruptions And Attacks, Hugh Medal

Graduate Theses and Dissertations

Recent events such as the 2011 Tohoku earthquake and tsunami in Japan have revealed the vulnerability of networks such as supply chains to disruptive events. In particular, it has become apparent that the failure of a few elements of an infrastructure system can cause a system-wide disruption. Thus, it is important to learn more about which elements of infrastructure systems are most critical and how to protect an infrastructure system from the effects of a disruption. This dissertation seeks to enhance the understanding of how to design and protect networked infrastructure systems from disruptions by developing new mathematical models and …