Digital Commons Network^™

Double-Pulse Nd:Yag-Co2 Libs Excitation For Bulk And Trace Analytes, Jason R. Becker, Patrick Skrodzki, Prasoon Diwakar, Sivanandan Harilal, Ahmed Hassanein

The Summer Undergraduate Research Fellowship (SURF) Symposium

Laser-induced breakdown spectroscopy [LIBS] is a commonly used technique for multi-element analyses for various applications such as space exploration, nuclear forensics, environmental analysis, process monitoring. The advantages of the LIBS technique include robustness, ease of use, field portability, and real-time, non-invasive multi-element analyses. However, in comparison to other lab based analytical techniques, it suffers from low precision and low sensitivity. In order to overcome these drawbacks, various approaches have been used, including double-pulse LIBS [DPLIBS]. Typically, various wavelength combinations of two Nd: yttrium aluminum garnet [YAG] lasers have been used for DPLIBS. However, the use of long wavelength (CO_{2 …}

Modeling Thermophotovoltaic Rare Earth Based Selective Emitters, Anubha Mathur, Enas Said Sakr, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

Thermophotovoltaic (TPV) devices convert heat to electricity using thermal radiation to illuminate a photovoltaic (PV) diode. Typically, this radiation is generated by a blackbody-like emitter. Such an emission spectrum includes a broad range of wavelengths, but only higher energy photons can be converted by the PV diode, which severely limits efficiencies. Thus, introducing a selective emitter and filter to recycle unwanted photons could potentially greatly enhance performance. In this work, we consider a rare earth-doped selective emitter structure to increase the number of photons emitted above the bandgap of the photovoltaic (PV) cell, while minimizing the total power emitted below …

Understanding And Assessing Engineering Practices In Indian Context, Rudie Desravines, Brent Jesiek, Kavitha Ramane, Qin Zhu

The Summer Undergraduate Research Fellowship (SURF) Symposium

For engineers and other technical professionals, working with individuals in a global context is often challenging and requires understanding and openness to other cultures. However, the core of engineering education has historically been focused on mathematical and technical foundations, with a lack of emphasis on broader capabilities such as global competency. Further research is needed to better understand differences in engineering education and practice across national and cultural boundaries, as well as to develop new instructional content and assessment techniques to improve and evaluate the global competency of engineering students and other technical professionals. This project addressed these needs through …

Identifying Candidate Genes That Affect Epidermal Development, Christina J. Smith, Longfei Wang, Michael V. Mickelbart

The Summer Undergraduate Research Fellowship (SURF) Symposium

The regulation of stomata, pores on the epidermis of leaves that allow for gas exchange, is an ideal target for creating a plant capable of acclimating to environmental stresses such as drought. Changes in stomatal density (SD) are correlated with different environments, but the identity of genes that act as modulators of SD are mostly unknown. To identify transcription factors that may act as modulators of SD, T-DNA mutants of candidate transcription factors identified in a genome-wide association study were characterized, and one candidate mutant displaying a phenotype was further characterized for anatomical and physiological traits. Expression of Arabidopsis thaliana …

Bayesian Calibration Tool, Sveinn Palsson, Martin Hunt, Alejandro Strachan

The Summer Undergraduate Research Fellowship (SURF) Symposium

Fitting a model to data is common practice in many fields of science. The models may contain unknown parameters and often, the goal is to obtain good estimates of them. A variety of methods have been developed for this purpose. They often differ in complexity, efficiency and accuracy and some may have very limited applications. Bayesian inference methods have recently become popular for the purpose of calibrating model's parameters. The way they treat unknown quantities is completely different from any classical methods. Even though the unknown quantity is a constant, it is treated as a random variable and the desired …

The Simulation Of Resonant Tunneling Diodes, Woodrow A. Gilbertson, Pengyu Long, Jim Fonseca, Gerhard Klimeck

The Summer Undergraduate Research Fellowship (SURF) Symposium

The goal of this project is to improve the simulation of an electrical device known as a Resonant Tunneling Diode (RTD). Diodes are in most electronic devices today, but RTDs have 10 times greater switching speeds than regular diodes. This increase in efficiency would have impacts from supercomputers to the next big cell phone. The increased functionality of the simulation tool will come from implementing more recent mathematical solvers and modeling techniques. The simulation tool makes use of a variant of Non-Equilibrium Green Functions (NEGF) with an effective mass approximation. The two contacts are treated as equilibrium regions and the …

Earth History Visualization System, Xinjie Lei, James G. Ogg

The Summer Undergraduate Research Fellowship (SURF) Symposium

Time Scale Creator (TSCreator), a geological chart generator, displays any portion of Earth history including chemo- magneto-, and other aspects. TSCreator is used by many universities, petroleum companies, and international geological surveys. In order to improve the quality of Time Scale Creator, tools were developed to provide users with more friendly graphical user interfaces (GUIs), accurate scaling of specific isotope, internationalization of data input and output, and smart depth scaling in wells to age conversion. To implement such tools, research for algorithm and common methods was basically done by searching articles online and reading posts on forums for Java developers. …

Simulating Nanoscale Optics In Photovoltaics With The S-Matrix Method, Dalton Chaffee, Xufeng Wang, Peter Bermel

The Summer Undergraduate Research Fellowship (SURF) Symposium

In the push to build high-efficiency solar cells with less materials usage, thin-film solar cells have attracted an increasing amount of interest. Thin films are particularly attractive if they could exhibit light trapping and photon recycling capabilities exceeding those of traditional wafer-based cells. Recent work by Alta Devices demonstrating a record single-junction efficiency of 28.8% with a gallium arsenide thin film cell shows the potential. However, most existing simulation tools do not handle these properties well -- particularly photon recycling. In this work, we develop an improved solar cell simulation tool to accurately predict thin-film performance. It is based on …

Reconstructing A Large-Scale Attribute-Based Social Network, Weijia Luo, Mario Ventresca

The Summer Undergraduate Research Fellowship (SURF) Symposium

An epidemic occurs when a disease rapidly infects substantially more people than expected compared to past experience of similar diseases. If an epidemic is not contained, it could turn into a pandemic, which will cause a worldwide crisis. Therefore, it is critical to determine and implement epidemic policies that are promising and effective within a short period of time. In this paper, we will develop tools that will allow us to recreate large-scale real-world social networks. Using such networks will enable us to simulate disease spread and determine critical personal and social factors that will be the key to containing …

Thermal Properties Of Soft Nanomaterials: Thermal Measurement Design, Yu Han, Meng Pan, Amy Marconnet, Collier Miers

The Summer Undergraduate Research Fellowship (SURF) Symposium

Soft materials like hydrogels have multiple tunable material properties because of their unique structures. Due to the ability to respond to stimuli like temperature or chemical environment, they have numerous applications in different fields like delivering drugs inside the human body and other medical uses. Details of the thermal transport mechanisms, as well as the overall thermal properties, are critical for a variety of applications. Multi-property measurements elucidate the underlying transport mechanisms in the soft materials. This research demonstrates a new methodology of measuring thermal properties of soft materials. This work uses the 3w method [1,2] for measuring the thermal …

Durability Assessment Of Concrete Structures In Hzm Sea Link Project For Design Life Of 120 Years, Kefei Li, Q. W. Li, Q. M. Zhang, Z. H. Fan, L. H. Yang

International Conference on Durability of Concrete Structures

This article presents the durability assessment of the concrete structures in the ongoing Hong Kong–Zhuhai–Macao (HZM) sea link project for a design service life of 120 years. During the preliminary study phase, the durability design of concrete structures has been performed by a model-based method with a partial factor scheme for chloride-induced corrosion process. On the basis of the actual design options adopted in the detailed design phase, the durability assessment of concrete structures is performed for the achieved durability and reliability levels. For this purpose, the durability assessment retains the same model for chloride-induced corrosion as in the preliminary …

Finite Volume Numerical Analysis Of The Thermal Property Of Cellular Concrete Based On Two And Three Dimensional X-Ray Computerized Tomography Images, She Wei, Yang Yonggan, Xie Deqing, Zhang Yunsheng

International Conference on Durability of Concrete Structures

Cellular concrete is one kind of lightweight concrete, which are widely used in thermal insulation engineering project. In this study, a three dimensional (2D and 3D) finite-volume-based models was developed for analyzing the heat transfer mechanisms through the porous structures of cellular concretes under steady-state heat transfer condition and also for investigating the differences between 2D and 3D modeling results. 2D and 3D reconstructed pore networks were generated from the microstructural information measured by a 3D image captured by X-ray computerized tomography (X-CT). In addition, the 3D-computed value of the effective thermal conductivity was found to be in better agreement …

Review Of Microbially Induced Corrosion And Comments On Needs Related To Testing Procedures, Mitchell House, W. J. Weiss

International Conference on Durability of Concrete Structures

Concrete is the most widely used material for the construction of the wastewater collection, storage, and treatment infrastructure. The chemical and physical characteristics of hydrated Portland cement may make it susceptible to degradation under highly acidic conditions. As a result, some concrete wastewater infrastructure may be susceptible to a multistage degradation process known as microbially induced corrosion (MIC). MIC begins with the production of aqueous hydrogen sulfide (H2S(aq)) by anaerobic sulfate-reducing bacteria present below the waterline. H2S(aq) partitions to the gas phase where it is oxidized to sulfuric acid by the aerobic sulfur-oxidizing bacteria Thiobacillus that resides on concrete surfaces …

Probabilistic Estimation Of Corrosion Propagation Period For Prestressed Concrete Structures Exposed To Chlorides, Radhakrishna G. Pillai, Jayachandran Karuppanasamy

International Conference on Durability of Concrete Structures

The overall service life of concrete structures can be divided into corrosion initiation and corrosion propagation phases. The durations of these two phases depend on the chloride threshold (Cl_th) and corrosion rate (i_corr), respectively, of the embedded steel reinforcement. Quantitative information on Cl_th and i_corr of conventional steel reinforcement are available in literature. Now‑a‑days, the use of prestressed concrete elements are rapidly increasing and there is a dire need for estimating their service life. Quantitative information on the Cl_th and i_corr of prestressing steel are required for this estimation. However, very limited …

Influence Of Controlled Permeability Formwork On The Permeability Of Concrete, Wei Lin, Q. Jiang, J. Liu, J. Liu

International Conference on Durability of Concrete Structures

Corrosion of steel reinforcement related to the intrusion of chloride ion is still the main threats to the durability of concrete structure, especially in marine environment. For the purpose of delaying the Cl⁻ concentration at the surface of steel reinforcement reaching the critical value leading to initial corrosion, the permeability of concrete is usually improved by optimizing the concrete mixture to achieve high compatibility as well as optimized pore structure. In recent years, controlled permeability formwork (CPF) which was originally developed to obtain much smoother surface of the concrete proves to promote the service performance of the concrete by …

Bring Your Own Device In The Information Literacy Classroom, Ilana Stonebraker, M Brooke Robertshaw, Hal Kirkwood, Mary Dugan

Libraries Faculty and Staff Scholarship and Research

In the 2013 school year, a team of librarians in the Parrish Library of Management and Economics at Purdue University taught a business information literacy course to approximately 500 management students in eight 70-person sessions. Due to limitations on a set of iPads borrowed from another department, one of two concurrent classes was taught with a set of iPads, while another had a Bring Your Own Device (BYOD) policy, where students brought their own laptops or iPads. Focus groups, observations of behavior, and final evaluations were utilized to evaluate the comparative perceived effectiveness of the two technology approaches. This paper …

Self-Assembled Tunable Photonic Hyper-Crystals, Vera N. Smolyaninova, Bradley Yost, David Lhneman, Evgenii Narimanov, Igor I. Smolyaninov

Birck and NCN Publications

We demonstrate a novel artificial optical material, the "photonic hyper-crystal'', which combines the most interesting features of hyperbolic metamaterials and photonic crystals. Similar to hyperbolic metamaterials, photonic hyper-crystals exhibit broadband divergence in their photonic density of states due to the lack of usual diffraction limit on the photon wave vector. On the other hand, similar to photonic crystals, hyperbolic dispersion law of extraordinary photons is modulated by forbidden gaps near the boundaries of photonic Brillouin zones. Three dimensional self-assembly of photonic hyper-crystals has been achieved by application of external magnetic field to a cobalt nanoparticle-based ferrofluid. Unique spectral properties of …

Hybridity And Dynamics Of An Individual’S Learning Styles, Quintana Marie Clark

Open Access Theses

Based on Kolb Learning Style Inventory 4.0, the objectives of this research were to demonstrate the existence of hybrid learning styles and demonstrate the existence of dynamic learning styles between subject matters (mathematics and English). Understanding an individual's dynamic distribution of learning styles might be used to further improve the quality of instruction, learning, and educational materials. Optimizing the quality of instruction, learning, and educational materials is important because careers in science, technology, engineering, and mathematics (STEM) fields are increasingly needed. Personalized learning has been identified as an area that could improve the quality of STEM education. Exploiting individuals learning …

Online Naturalization: Evolving Roles In Online Knowledge Production Communities, Jeremy David Foote

Open Access Theses

Web-based peer production communities, like Wikipedia and open source software, have created digital artifacts of growing cultural, financial, and technological importance. Understanding how and why people choose to join these communities, and why they eventually leave them, is therefore an important topic.

We take all of the edit data from six years of activity on the online genealogy wiki WeRelate, and create monthly snapshots of behavior and interaction networks for all 9,570 users who edited the site. We use machine learning to cluster these behavioral snapshots into four "behavioral roles". We identify one of these roles as being indicative of …

Study Of A Generalized Empirical Model For Predicting Pressure Drop For Internal Flows, Tejas Anup Pant

Open Access Theses

A generalized empirical model for estimating the pressure drop across a channel for a given massflow rate is studied through computational fluid dynamics (CFD) simulations. It is observed that for developing laminar and turbulent flow through channels and pipes of arbitrary cross-section, the variation in the pressure drop between any two points in the flow direction with massflow rate can be well approximated by a second degree expression in massflow rate which is referred to as the empirical model in this study. In the first part of this study, a correlation between the pressure gradient and the massflow rate is …

Fundamental Studies On Copper Zeolites For Catalytic No X Abatement, Anuj Arun Verma

Open Access Dissertations

Stringent regulations in mobile NOx emissions have resulted in the development of Standard Selective Catalytic Reduction (SCR) as the dominant NOx abatement technology in lean burn diesel engines. Standard SCR is a reaction of nitric oxide (NO) with ammonia (NH₃), in the presence of oxygen (O ₂) to form nitrogen (N₂) and water (H₂O). Copper containing zeolites show commercially viable SCR performance. Cu-SSZ-13 (CHA framework), a member of this family, is a preferred catalyst for SCR applications because it shows exceptional hydrothermal stability in addition to commercially viable SCR performance. Our work focuses …

Development Of A Real Time Bistatic Radar Receiver Using Signals Of Opportunity, Nicholas Rainville

Open Access Theses

Passive bistatic radar remote sensing offers a novel method of monitoring the Earth's surface by observing reflected signals of opportunity. The Global Positioning System (GPS) has been used as a source of signals for these observations and the scattering properties of GPS signals from rough surfaces are well understood. Recent work has extended GPS signal reflection observations and scattering models to include communications signals such as XM radio signals. However the communication signal reflectometry experiments to date have relied on collecting raw, high data-rate signals which are then post-processed after the end of the experiment. This thesis describes the development …

A Fesability Analysis Of A Novel Constructed Wetland Design Tool For Arusha, Tanzania, Michael R. Sheehan

Open Access Theses

While water is a resource necessary for all life, in Tanzania alone over 20 million people who live in rural areas have no access to improved water sources. Water stress is a major concern in rural Tanzania, where annual potential evaporation can outpace precipitation by hundreds of mm per year. There is a significant need for improved access to water sources for Tanzanians living in rural regions of Arusha. To improve access to water, both water quantity and quality need to be addressed in a treatment system. Various water collection and treatment systems were compared and contrasted through the lens …

Clinical Investigation Of Plethysmographic Variability Index: A Derivative Index Of Pulse Oximetry In Anesthetized Dogs, Vaidehi V. Paranjape

Open Access Theses

Plethysmographic Variability Index (PVI) is a derivative index of pulse oximetry that allows evaluating an individual's intravascular volume status. Perfusion Index (PI) represents the strength of pulse signal at the anatomic site of measurement from which PVI is calculated using changes in PI over respiratory cycles. Plethysmographic Variability Index has been used to detect hypovolemia and predict fluid responsiveness in mechanically ventilated human patients however, fewer studies are available in spontaneously breathing patients. The use of PVI has not been explored extensively in dogs so far. The goals of this study were to establish a common range for PVI and …

A Small-Scale Experiment Using Microwave Interferometry To Investigate Detonation And Shock-To-Detonation Transition In Pressed Tatb, Peter John Renslow

Open Access Theses

A small-scale characterization test utilizing microwave interferometry was developed to dynamically measure detonation and run to detonation distance in explosives. The technique was demonstrated by conducting two experimental series on the well-characterized explosive triaminotrinitrobenzene (TATB). In the first experiment series, the detonation velocity was observed at varying porosity. The velocity during TATB detonation matched well with predictions made using CHEETAH and an empirical relation from the Los Alamos National Laboratory (LANL). The microwave interferometer also captured unsteady propagation of the reaction when a low density charge was near the failure diameter. In the second experiment series, Pop-plots were produced using …

Light Off Temperature Based Approach To Determine Diesel Oxidation Catalyst Effectiveness Level And The Corresponding Outlet No And No2 Characteristics, Prateek Tayal

Open Access Theses

According to the latest EPA emission regulations, the NO_x (Nitrogen oxide compounds) emissions from heavy duty compression ignition engines need to see a dramatic reduction. The current technology used for this purpose is the selective catalytic reduction (SCR) system, which achieves NO_x reduction of around 90% [9]. This involves urea injection which is influenced by the NO: NO₂ ratio at the inlet to the SCR. Thus, the role of the DOC (Diesel Oxidation Catalyst) where most of the oxidation of the NO_x compounds takes place, comes to fore. The focus is also on the effectiveness of …

Using The Microsoft Kinect To Assess Human Bimanual Coordination, Joshua James Liddy

Open Access Theses

Optical marker-based systems are the gold-standard for capturing three-dimensional (3D) human kinematics. However, these systems have various drawbacks including time consuming marker placement, soft tissue movement artifact, and are prohibitively expensive and non-portable. The Microsoft Kinect is an inexpensive, portable, depth camera that can be used to capture 3D human movement kinematics. Numerous investigations have assessed the Kinect's ability to capture postural control and gait, but to date, no study has evaluated it's capabilities for measuring spatiotemporal coordination. In order to investigate human coordination and coordination stability with the Kinect, a well-studied bimanual coordination paradigm (Kelso, 1984, Kelso; Scholz, & …

Experimental Study Of Unsteady Heat Release In An Unstable Single Element Lean Direct Injection (Ldi) Gas Turbine Combustor, Varun S. Lakshmanan

Open Access Theses

In an effort to curb emissions from gas turbine engines, many low emission engine concepts have been developed. Among the most promising of these is the LDI (Lean Direct Injection). These systems operate at relatively low equivalence ratios close to blowout and are prone to instabilities. Combustion instabilities can reduce the life of the combustor by causing large pressure fluctuations and enhanced heat release to the walls of the combustor and reduce the efficiency of the engines. The understanding of combustion instabilities is vital to the implementation of such systems. Combustion instabilities are studied in an self-excited single element gas …

Physical And Chemical Attributes Of A Genetically Modified Fruit Pectin, Carl Patrick Littrell

Open Access Theses

Pectin is an important polymer used in the food industry as a thickening and gelling agent. Though pectin is ubiquitous in plants, chemical and structural differences among pectin molecules prevent most from being viable for industrial use. Enzymes found naturally in fruit cell walls during the ripening process impair many desirable attributes of fruit pectins, rendering them unsuitable for industrial applications. Pectin methylesterase (PME) is one such enzyme whose expression can be altered during ripening through the use of recombinant genetic engineering. Reduction in levels of PME results in increased degree of methylation and molecular size of pectin, greatly increasing …

The Impact Of User Centered Design On Student Motivation, Craig T. Locker

Open Access Theses

There is a current push for STEM education within the U.S.; however current studies show that students' interest to pursue STEM fields is decreasing as they progress through high school. This lose in interest has shown to have a strong tie to students' perceived levels of motivation towards the subject. The question that this studied set out to answer was if user centered design (UCD) would affect students perceived level of motivation. For this study a treatment of UCD was compared to a traditional high school engineering design curriculum, with the goal to identify if UCD would have a positive …