Digital Commons Network^™

Principals Partnering To Build A Vision For School Mathematics, V. Inge, V. Hodges, P. Robertson

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

Aims & Scope

Journal of Mathematics and Science: Collaborative Explorations

No abstract provided.

Learning Together: Using Action Research To Design Professional Development, M. Alger, R. White

Journal of Mathematics and Science: Collaborative Explorations

After being part of a week-long math institute, both the principal and the Mathematics Specialist from an urban school district partnered to develop a professional development plan. It incorporated a Lesson Study Model that supported collaborative learning teams, focused on the instructional process, and incorporated reflection and feedback. Although the faculty had engaged in other forms of professional development, the lesson study process was seen as a powerful vehicle that invited a level of coaching and cross-collaboration. This article focuses on the shared viewpoints of the principal and the Mathematics Specialist who worked together to build a mechanism for professional …

Theoretical Investigations Of Pt_3x (X = Al, Sc, Hf, Zr) Ground State, Adewumi Isaac Popoola, Lesley Heath Chown, Lesley Alison Cornish

Turkish Journal of Physics

The electronic structure of Pt_3X compounds showed that Pt_3Hf and Pt_3Zr were more stable for the D0_{24} structure, rather than L1_2. The compound Pt_3Al was predicted to be the hardest and most ductile, but not with the L1_2 structure at ground state. The density of states showed that Pt_3Hf, Pt_3Zr, and Pt_3Al can be stabilized to the L1_2 phase with suitable element addition. All calculations were done within the density functional theory framework.

A Model Of The Multijunction Ac Josephson Effect In A Superconductor, Mohammed Rafiqul Islam, Habibur Rahman

Turkish Journal of Physics

We present a model of the multijunction ac Josephson effect in a superconductor. Josephson predicted that at a finite applied voltage (V_o) an alternating supercurrent of frequency \omega_J =2eV_o/\hslash flows between 2 superconductors separated by an insulating layer, called the ac Josephson effect. Adding 2 or more Josephson junctions (so-called multijunction) with an applied voltage, we have shown that the resultant current (which is equivalent to the vector sum of the currents in each junction) has the same frequency as the single Josephson junction. The amplitude of the resultant current for the multijunction is increased with the increasing number of …

Aldimine Derivatives As Photosensitizers For Dye-Sensitized Solar Cells, Amal Y. Batniji, Rami Morjan, Monzir S. Abdel-Latif, Taher M. El-Agez, Sofyan A. Taya, Hatem S. El-Ghamri

Turkish Journal of Physics

Five aldimine derivatives were prepared by condensation of the appropriate amine with salicylaldehyde (m1-m4) and 4-aminobenzoic acid with 2-thiophene carboxaldehyde (m5). A molar ratio of 1:1 was used and the mixture was refluxed in ethanol for 2 h to obtain the corresponding aldimine derivative. These derivatives were used as photosensitizers for dye-sensitized solar cells (DSSCs). The best performance was obtained for the DSSC sensitized with 2-(2-hydroxybenzylideneamino)benzoic acid, for which a short-circuit current of 2.86 mA/cm^2, an open-circuit voltage of 0.562 V, and an efficiency of 0.575% were obtained.

Xrd, Xps, And Optical Characterizations Of Al-Doped Zno Film Grown On Gaas Substrate, Ebru Şenadim Tüzemen, Hülya Şahi̇n, Kamuran Kara, Sezai̇ Elagöz, Ramazan Esen

Turkish Journal of Physics

A ZnO:Al (10%) thin film was prepared on GaAs(100) substrate by using a pulsed filtered cathodic vacuum arc deposition (PFCVAD) system. The ZnO:Al thin film was thermally annealed for 1 h at 2 different temperatures in air. The film structure was investigated as a function of annealing temperature by X-ray diffraction (XRD). ZnO:Al film annealed at 500 °C by PFCVAD method resulted in an amorphous film. However, after annealing ZnO:Al film at 600 °C, it showed (100) and (002) peaks at around 32° and 34°, respectively. The chemical state of ZnO:Al (AZO) film on GaAs substrate was investigated by using …

Deposition And Characterization Of Pbo--Pbs Multilayer Thin Films By Solution Growth Technique, Dominic Eya

Turkish Journal of Physics

PbO-PbS thin films were deposited on glass substrates using the chemical bath deposition (CBD) technique. PbO thin films were deposited from the solution of lead nitrate (Pb(NO_3)_2) and sodium hydroxide (NaOH). Ethylenediaminetetraacetate (EDTA) served as the complexing agent. Some of the PbO films were used as substrate for the deposition of PbS. The PbS was deposited from alkaline solution of lead nitrate and thioacetamide. Triethanolamine was used as the complexing agent. Some of the films were subjected to thermal treatment after deposition. Energy dispersive X-ray fluorescence analysis confirmed the presence of Pb and S in the PbS thin films, while …

Quantum Chemical Calculations Of The Polymorphic Phase Transition Temperatures Of Zns, Znse, And Znte Crystals, Raşi̇t Ahiska, Dmytro Freik, Taras Parashchuk, Igor Gorichok

Turkish Journal of Physics

Molecular models of polymorphs modifications of zinc chalcogenides have been designed. Based on the results of ab initio quantum chemical calculations of the crystal structure of clusters the temperature dependences of the Gibbs energy of sphalerite and of wurtzite have been found. Phase transformations \"sphalerite-wurtzite\" temperatures have been evaluated.

An Investigation On Silar Deposited Cu_Xs Thin Films, Aykut Astam, Yunus Akaltun, Muhammet Yildirim

Turkish Journal of Physics

A copper sulfide thin film was deposited on glass substrate by successive ionic layer adsorption and reaction method at room temperature, using cupric sulfate and sodium sulfide aqueous solutions as precursors. The structural, surface morphological, optical, and electrical properties of the as-deposited film were investigated via X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, optical absorption, and d.c. 2-point probe methods. The film was found to be amorphous, dense, and uniform. Average atomic percentage of Cu:S in the as-deposited film was calculated as 63:37. The band gap energy of copper sulfide thin film was found to be 2.14 eV …

The Interactions Between Jak/Stat Signaling Ligands In Drosophila Melanogaster, Qian Chen

Theses and Dissertations--Biology

The development of multi-cellular organisms requires extensive cell-cell communication to coordinate cell functions. However, only a handful of signaling pathways have emerged to mediate all the intercellular communications; therefore, each of them is under an array of regulations to achieve signaling specificity and diversity. One such signaling pathway is the Janus Kinase/ Signal Transducer and Activator of Transcription (JAK/STAT) pathway, which is the primary signaling cascade responding to a variety of cytokines and growth factors in mammals and involved in many developmental processes. This signaling pathway is highly conserved between mammals and Drosophila, …

Hybrid Power System Options For Off-Grid Rural Electrification In Northern Kenya, June M. Lukuyu, Judith Cardell

Engineering: Faculty Publications

For domestic consumers in the rural areas of northern Kenya, as in other developing countries, the typical source of electrical supply is diesel generators. However, diesel generators are associated with both CO2 emissions, which adversely affect the environment and increase diesel fuel prices, which inflate the prices of consumer goods. The Kenya government has taken steps towards addressing this issue by proposing The Hybrid Mini-Grid Project, which involves the installation of 3 MW of wind and solar energy systems in facilities with existing diesel generators. However, this project has not yet been implemented. As a contribution to this effort, this …

Integrated Consensus Based Frameworks For Unmanned Vehicle Routing And Targeting Assignment, Waleed T. Barnawi

Dissertations

Unmanned aerial vehicles (UAVs) are increasingly deployed in complex and dynamic environments to perform multiple tasks cooperatively with other UAVs that contribute to overarching mission effectiveness. Studies by the Department of Defense (DoD) indicate future operations may include anti-access/area-denial (A2AD) environments which limit human teleoperator decision-making and control. This research addresses the problem of decentralized vehicle re-routing and task reassignments through consensus-based UAV decision-making. An Integrated Consensus-Based Framework (ICF) is formulated as a solution to the combined single task assignment problem and vehicle routing problem. The multiple assignment and vehicle routing problem is solved with the Integrated Consensus-Based Bundle Framework …

Status Quo Bias And Ambiguity Aversion In Engineers, Christopher L. Brown

Dissertations

Systems engineers routinely engage in exercises, such as a trade studies or Multiple Criteria Decision Analysis processes, to select the best among multiple options. Managers ideally assume that these processes are conducted in a manner that is strictly rational and repeatable. A cognitive bias leading to selection of a sub-optimal choice could then have significant consequences. Research has demonstrated a number of biases in the general population, but these have not been specifically studied in systems engineers. Two such biases are ambiguity aversion and status quo bias. A survey instrument was developed to test for ambiguity aversion and status quo …

Computational Optimization Models For Investigating Digital Crime And Intrusion Detection Alarms, Ezhil Selvam Kalaimannan

Dissertations

The Internet is a source of information, communication and entertainment, which makes it impossible for us to imagine a world without being connected. However, there has been a tremendous growth of crimes targeting any form of digital medium. The main objective of this dissertation is to develop and empirically evaluate computational optimization models for investigating digital crime and computer/network intrusion. The first research problem considered in this dissertation relates to the Crime Scene Investigation (CSI) in digital forensics. First, a mixed integer linear programming (MILP) model is proposed to allocate optimal investigation times for evidence, thereby maximizing the overall effectiveness …

Modular Network Construction Using Eqtl Data: An Analysis Of Computational Costs And Benefits, Yen Yi Ho, Leslie M. Cope, Giovanni Parmigiani

Faculty Publications

Background: In this paper, we consider analytic methods for the integrated analysis of genomic DNA variation and mRNA expression (also named as eQTL data), to discover genetic networks that are associated with a complex trait of interest. Our focus is the systematic evaluation of the trade-off between network size and network search efficiency in the construction of these networks. Results: We developed a modular approach to network construction, building from smaller networks to larger ones, thereby reducing the search space while including more variables in the analysis. The goal is achieving a lower computational cost while maintaining high confidence in …

Modeling And Validation Of A Synchronous-Machine/Controlled-Rectifier System, Kyle A. Hord

Theses and Dissertations--Electrical and Computer Engineering

The hardware validation of a novel average-value model (AVM) for the simulation of a synchronous-generator/controlled rectifier system is presented herein. The generator is characterized using genetic algorithm techniques to fit standstill frequency response (SSFR) measurements to q and d-axis equivalent circuits representing the generator in the rotor reference frame. The generator parameters form the basis of a detailed model of the system, from which algebraic functions defining the parametric AVM are derived. The average-value model is compared to the physical system for a variety of loading and operating conditions including step load change, change in delay angle, and external closed-loop …

Model Analysis And Predictive Control Of Double Electrode Submerged Arc Welding Process For Fillet Joints With Root Opening, Yi Lu

Theses and Dissertations--Electrical and Computer Engineering

Submerged Arc Welding (SAW) for fillet joints is one of the major applications in the shipbuilding industry. Due to the requirement for the weld size, a sufficient amount of metal must be deposited. In conventional SAW process, the heat input is proportional to the amount of metal melted and is thus determined by the required weld size. To meet this requirement, an excessive amount of heat is applied causing large distortions on the welded structures whose follow-up straightening is highly costly. In order to reduce the needed heat input, Double-Electrode (DE) technology has been practiced creating the Double-Electrode SAW (DE-SAW) …

Machine-Human Cooperative Control Of Welding Process, Weijie Zhang

Theses and Dissertations--Electrical and Computer Engineering

An innovative auxiliary control system is developed to cooperate with an unskilled welder in a manual GTAW in order to obtain a consistent welding performance. In the proposed system, a novel mobile sensing system is developed to non-intrusively monitor a manual GTAW by measuring three-dimensional (3D) weld pool surface. Specifically, a miniature structured-light laser amounted on torch projects a dot matrix pattern on weld pool surface during the process; Reflected by the weld pool surface, the laser pattern is intercepted by and imaged on the helmet glass, and recorded by a compact camera on it. Deformed reflection pattern contains the …

Reference Compensation For Localized Surface-Plasmon Resonance Sensors, Neha Nehru

Theses and Dissertations--Electrical and Computer Engineering

Noble metal nanoparticles supporting localized surface plasmon resonances (LSPR) have been extensively investigated for label free detection of various biological and chemical interactions. When compared to other optical sensing techniques, LSPR sensors offer label-free detection of biomolecular interactions in localized sensing volume solutions. However, these sensors also suffer from a major disadvantage – LSPR sensors remain highly susceptible to interference because they respond to both solution refractive index change and non-specific binding as well as specific binding of the target analyte. These interactions can severely compromise the measurement of the target analyte in a complex unknown media and hence limit …

Single Ended Traveling Wave Based Fault Location Using Discrete Wavelet Transform, Jin Chang

Theses and Dissertations--Electrical and Computer Engineering

In power transmission systems, locating faults is an essential technology. When a fault occurs on a transmission line, it will affect the whole power system. To find the fault location accurately and promptly is required to ensure the power supply. In this paper, the study of traveling wave theory, fault location method, Karrenbauer transform, and Wavelet transform is presented. This thesis focuses on single ended fault location method. The signal processing technique and evaluation study are presented. The MATLAB SimPowerSystem is used to test and simulate fault scenarios for evaluation studies.

Volume And Surface Integral Equations For Solving Forward And Inverse Scattering Problems, Xiande Cao

Theses and Dissertations--Electrical and Computer Engineering

In this dissertation, a hybrid volume and surface integral equation is used to solve scattering problems. It is implemented with RWG basis on the surface and the edge basis in the volume. Numerical results shows the correctness of the hybrid VSIE in inhomogeneous medium. The MLFMM method is also implemented for the new VSIEs.

Further more, a synthetic apature radar imaging method is used in a 2D microwave imaging for complex objects. With the mono-static and bi-static interpolation scheme, a 2D FFT is applied for the imaging with the data simulated with VSIE method. Then we apply a background cancelling …

Multifrequency Averaging In Power Electronic Systems, Fei Pan

Theses and Dissertations--Electrical and Computer Engineering

Power electronic systems have been widely used in the electrical power processing for applications with power levels ranging from less than one watt in battery-operated portable devices to more than megawatts in the converters, inverters and rectifiers of the utility power systems. These systems typically involve the passive elements such as inductors, capacitors, and resistors, the switching electronic components such as IGBTs, MOSFETS, and diodes, and other electronic circuits. Multifrequency averaging is one of the widely used modeling and simulation techniques today for the analysis and design of power electronic systems. This technique is capable of providing the average behavior …

Coordinated Voltage And Reactive Power Control Of Power Distribution Systems With Distributed Generation, Esa A. Paaso

Theses and Dissertations--Electrical and Computer Engineering

Distribution system voltage and VAR control (VVC) is a technique that combines conservation voltage reduction and reactive power compensation to operate a distribution system at its optimal conditions. Coordinated VVC can provide major economic benefits for distribution utilities. Incorporating distributed generation (DG) to VVC can improve the system efficiency and reliability. The first part of this dissertation introduces a direct optimization formulation for VVC with DG. The control is formulated as a mixed integer non-linear programming (MINLP) problem. The formulation is based on a three-phase power flow with accurate component models. The VVC problem is solved with a state of …

Adeno-Associated Virus (Aav) Transduction Of Primary Human Cd4+T Lymphocytes, Sahar Hussein Kamel

Browse all Theses and Dissertations

Development of latent HIV-infected CD4+ T lymphocytes is the major cause of HIV treatment failure. Adeno-associated virus (AAV) is an attractive vector for anti-HIV gene therapy due to its lack of pathogenicity, low immunogenicity, and persistent transgene expression. However, a major limitation for AAV gene transfer is the cell-specific tropism of each serotype. Only AAV serotypes 2 and 5 have been investigated in hematopoietic cells, both of these serotypes have shown low transduction efficiency. Since each of the currently described AAV serotypes demonstrate distinct tissue tropism, I hypothesized that other serotypes such as AAV1, 4, 8, or 9 may demonstrate …

Expression Of The Alpha, Beta, And Gamma Subunits Of The Interleukin-2 Receptor By Human Vascular Smooth Muscle Cells, Sultan Mohammed Alhayyani

Browse all Theses and Dissertations

Interleukin 2 (IL-2) is a member of the cytokine family and contributes to the proliferation, survival, and death of lymphocytes [1]. The interleukin-2 receptor (IL-2) is a tripartite receptor commonly expressed on the surfaces of many lymphoid cells and is composed of three non-covalently associated subunits, alpha (CD25), beta (CD122), and gamma (CD132) [2]. Our laboratory has previously described IL-2 receptor Beta expression by vasculature smooth muscle cells (VSMC) in mice and humans [3]. The current work expands our previous observations by assessing the expression of the alpha and gamma subunits of the IL-2R by VSMCs. Analysis of IL-2R expression …

Full Wave Electromagnetic Simulations Of Terahertz Wire Grid Polarizers And Infrared Plasmonic Wire Gratings, John Cetnar

Browse all Theses and Dissertations

This dissertation is a study of the interaction of terahertz (THz) and long-wave infrared (LWIR) radiation with various periodic sub-wavelength metallic structures in free-space and on dielectric substrates. There are many new and useful applications for both THz and LWIR radiation. Unfortunately, heavy attenuation by the Earth's atmosphere and low output power from THz sources combine to make THz radiation weak and difficult to detect. LWIR is not as prone to atmospheric attenuation as THz radiation. Nevertheless, the detection of LWIR can be improved upon by strengthening the coupling between incoming radiation and LWIR detector systems.

Light passing through periodic …

Phylogenetics, Population Genetics, And Evolution Of The Mallard Complex, Philip Lavretsky

Browse all Theses and Dissertations

Speciation is primarily regarded as an ancestral split that results in two distinct taxonomic units, and proceeds in stages along a continuum from initiation (i.e., population divergence) to completion (i.e., reproductively isolated species). Establishing how and why populations diverge, including the primary mechanisms influencing these events is a major objective for evolutionary scientists. Focusing on incipient forms, researchers attempt to disentangle the antagonistic nature of selection, genetic drift, and gene flow in the speciation process.

In chapter 1, I investigate the phylogenetic relationships of 14 closely related taxa within the mallard complex (Anas spp.) that underwent a radiation within the …

Rings Of Frobenius Operators, Mordechai Katzman, Karl Schwede, Anurag K. Singh, Wenliang Zhang

Department of Mathematics: Faculty Publications

Let R be a local ring of prime characteristic. We study the ring of Frobenius operators F(E), where E is the injective hull of the residue field of R. In particular, we examine the finite generation of F(E) over its degree zero component F⁰(E), and show that F(E) need not be finitely generated when R is a determinantal ring; nonetheless, we obtain concrete descriptions of F(E) in good generality that we use, for example, to prove the discreteness of F-jumping numbers for arbitrary ideals in determinantal rings.

Bootsie – Estimation Of Coefficient Of Variation Of Aflp Data By Bootstrap Analysis, Justin Payne, Erica Lindroth, K. M. Kneeland, Steven R. Skoda, Fatima Mustafa, Muhammad Irfan Ullah, John E. Foster

Department of Entomology: Faculty Publications

Bootsie is an English-native replacement for ASG Coelho's “DBOOT” utility for estimating coefficient of variation of a population of AFLP marker data using bootstrapping. Bootsie improves on DBOOT by supporting batch processing, time-to-completion estimation, builtin graphs, and a suite of export tools for creating data files for other population genetics software.