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Articles 31 - 60 of 72
Full-Text Articles in Physical Sciences and Mathematics
Patterns Of Abundance Across An Urban-Rural Gradient For Commonly Found Indigenous Arthropods, David Jones
Patterns Of Abundance Across An Urban-Rural Gradient For Commonly Found Indigenous Arthropods, David Jones
Theses and Dissertations
Abstract Proof of concept for a continuous environmental sampling methodology that employs common terrestrial arthropods as environmental samplers was tested by analyzing pitfall, malaise and black light captures over a six month period over a replicated urban-suburban-rural gradient in Central Virginia. All arthropods captured at the nine sites were identified and assigned to aquatic, vegetation, or soil groups based on their association with these microhabitats. To offset variability in arthropod life history patterns and species abundance within habitat types, arthropod categories based on presence/absence data over the six month period were constructed to provide for sampling reliability within each microhabitat …
Poly(Styrene-Co-Vinylbenzylchloride-Co-Divinylbenzene) Coated Iron Oxide: Synthesis And Effects On Size And Morphology, M. D. Shultz, J. R. Marin, S. H. Naik, J. Wilkins, J. M. Laza, J. L. Vilas, M. Rodriguez, N. Perez, E. E. Carpenter
Poly(Styrene-Co-Vinylbenzylchloride-Co-Divinylbenzene) Coated Iron Oxide: Synthesis And Effects On Size And Morphology, M. D. Shultz, J. R. Marin, S. H. Naik, J. Wilkins, J. M. Laza, J. L. Vilas, M. Rodriguez, N. Perez, E. E. Carpenter
Chemistry Publications
Iron oxide nanoparticles were coated with a polymer synthesized from the monomers of styrene, divinylbenzene, and vinylbenzylchloride. The resultant polymer microspheres from synthesis without nanoparticle loading are primarily monodispersed with a diameter of 3.45 μm as measured by scanning electron microscopy. The addition of 1% nanoparticles by mass appears to decrease the size of the microspheres down to 2.04 μm as well as increase the polydispersity. This trend is also seen to continue as you add more nanoparticles to the system going from 3.45 μm with 0% nanoparticles down to below 1 μm for 5% nanoparticles. This indicates that the …
Oregon Mathematics Leadership Institute Project: Evaluation Results On Teacher Content Knowledge, Implementation Fidelity, And Student Achievement, D. Weaver, T. Dick
Oregon Mathematics Leadership Institute Project: Evaluation Results On Teacher Content Knowledge, Implementation Fidelity, And Student Achievement, D. Weaver, T. Dick
Journal of Mathematics and Science: Collaborative Explorations
The Oregon Mathematics Leadership Institute (OMLl) National Science Foundation Mathematics and Science Partnership project partners are Oregon State University, Portland State University, Teachers Development Group, and ten Oregon school districts. The primary activities of the project were a sequence of three intensive three-week residential institutes emphasizing mathematics content knowledge for teaching, collegial leadership, and the building of Professional Learning Communities. Teachers at all levels of grades K-12 participated together in the mathematics content courses. By the conclusion of the. third Summer Institute, teachers had shown significant improvements in mathematical content knowledge for teaching. Analysis of student achievement data in participating …
Microscopic Dynamics Of The Orientation Of A Hydrated Nanoparticle In An Electric Field, C. D. Daub, D. Bratko, A. Towshif, A. Luzar
Microscopic Dynamics Of The Orientation Of A Hydrated Nanoparticle In An Electric Field, C. D. Daub, D. Bratko, A. Towshif, A. Luzar
Chemistry Publications
We use atomistic simulations to study the orientational dynamics of a nonpolar nanoparticle suspended in water and subject to an electric field. Due to molecular-level effects we describe, the torque exerted on the nanoparticle exceeds continuum-electrostatics based estimates by about a factor of two. The reorientation time of a 16.2×16.2×3.35 ̊A3 nanoparticle in a field E > 0.015V/ ̊A is an order of magnitude less than the field-free orientational time (∼ 1 ns). Surprisingly, the alignment speed is nearly independent of the nanoparticle size in this regime. These findings are relevant for design of novel nanostructures and sensors and development of …
Origin Of The Anatase To Rutile Conversion Of Metal-Doped Tio2, Sa Li, Puru Jena
Origin Of The Anatase To Rutile Conversion Of Metal-Doped Tio2, Sa Li, Puru Jena
Physics Publications
Extensive calculations using density functional theory enable us to explain the origin of the surprising room-temperature conversion of anatase to rutile phase of TiO2 when doped with Co and Ni, but not with Cu. Contrary to earlier suggestion, neither high spin nor strain of the transition metals is found to be responsible for this phase conversion. The driving mechanism, instead, is attributed to the increased interaction between Co and Ni atoms forming a linear chain in the rutile phase. We predict that Cr and Mn which have even larger spins than Co and Ni cannot induce this phase conversion.
Magnetic Properties Of Transition-Metal-Doped Zn1−Xtxo (T=Cr, Mn, Fe, Co, And Ni) Thin Films With And Without Intrinsic Defects: A Density Functional Study, Qian Wang, Qiang Sun, Puru Jena, Y. Kawazoe
Magnetic Properties Of Transition-Metal-Doped Zn1−Xtxo (T=Cr, Mn, Fe, Co, And Ni) Thin Films With And Without Intrinsic Defects: A Density Functional Study, Qian Wang, Qiang Sun, Puru Jena, Y. Kawazoe
Physics Publications
Theoretical calculations based on density-functional theory and generalized gradient approximation have been carried out in studying the electronic structure and magnetic properties of transition-metal-doped Zn1−xTxO (T=Cr, Mn, Fe, Co, and Ni) (112¯0) thin films systematically with and without intrinsic point defects (e.g., vacancies and interstitials), and as function of concentration and distribution of dopants and vacancies. Using large supercells and geometry optimization without symmetry constraint, we are able to determine the sites that metal atoms prefer to occupy, their tendency to cluster, the preferred magnetic coupling between magnetic moments at transition-metal sites, and the effect of intrinsic point defects on …
Electronic Behavior Of The Zn- And O-Polar Zno Surfaces Studied Using Conductive Atomic Force Microscopy, J. C. Moore, S. M. Kenny, C. S. Baird, H. Morkoç, A. A. Baski
Electronic Behavior Of The Zn- And O-Polar Zno Surfaces Studied Using Conductive Atomic Force Microscopy, J. C. Moore, S. M. Kenny, C. S. Baird, H. Morkoç, A. A. Baski
Physics Publications
We have used conducting atomic force microscopy (CAFM) to study the morphology and electronic behavior of as-received and air-annealed (0001) Zn- and (0001¯) O-polar surfaces of bulk ZnO. Both polar surfaces exhibit relatively flat morphologies prior to annealing, which rearrange to form well-defined steps upon annealing in air at 1050 °C for 1 h. Long-term exposure to air results in surface layer pitting and the destruction of steps for both the as-received and air-annealed (0001¯)surfaces, indicating its enhanced reactivity relative to the (0001) surface. CAFM I-V spectra for polar surfaces are similar and indicate Ohmic to rectifying behavior that depends …
Magnetic Response Of Core-Shell Cobalt Ferrite Nanoparticles At Low Temperature, K. Maaz, M. Usman, S. Karim, A. Mumtaz, S. K. Hasanain, M. F. Bertino
Magnetic Response Of Core-Shell Cobalt Ferrite Nanoparticles At Low Temperature, K. Maaz, M. Usman, S. Karim, A. Mumtaz, S. K. Hasanain, M. F. Bertino
Physics Publications
Cobaltferritenanoparticles (size: 26±4nm) have been synthesized by coprecipitation route. The coercivity of nanoparticles follows a simple model of thermal activation of particle moments over the anisotropy barrier in the temperature range of 30–300K in accordance with Kneller’s law; however, at low temperatures (
Photoelectron Imaging And Theoretical Investigation Of Bimetallic Bi1–2ga−0–2 And Pb−1–4 Cluster Anions, M. A. Sobhy, J. Ulises Reveles, Ujjwal Gupta, Shiv N. Khanna, A. W. Castleman Jr.
Photoelectron Imaging And Theoretical Investigation Of Bimetallic Bi1–2ga−0–2 And Pb−1–4 Cluster Anions, M. A. Sobhy, J. Ulises Reveles, Ujjwal Gupta, Shiv N. Khanna, A. W. Castleman Jr.
Physics Publications
We present the results of photoelectron velocity-map imaging experiments for the photodetachment of small negatively charged BimGan (m=1–2, n=0–2), and Pbn (n=1–4) clusters at 527 nm. The photoelectron images reveal new features along with their angular distributions in the photoelectron spectra of these clusters. We report the vertical detachment energies of the observed multiple electronic bands and their respective anisotropy parameters for the BimGan and Pbn clusters derived from the photoelectron images. Experiments on the BiGan clusters reveal that the electron affinity increases with the number of Ga atoms from n=0 to 2. The BiGa−2 cluster is found to be …
Doping Induced Anisotropic Growth In C60, Miao Miao Wu, Qiang Sun, Puru Jena, Yoshiyuki Kawazoe
Doping Induced Anisotropic Growth In C60, Miao Miao Wu, Qiang Sun, Puru Jena, Yoshiyuki Kawazoe
Physics Publications
Using density functional theory with generalized gradient approximation for exchange and correlation energy, we show that substitution of a Si atom at one of the C sites in C60 not only allows C59Si to have a hydrophobic head with a hydrophilic tail but also the Si atom acts as a seed for anisotropic growth of the heterofullerene. This is demonstrated by interacting C59Si with N7Sc and B8Si. The resulting complex structures exhibit enhanced electric dipole moments and anisotropy. Thus, doping induced anisotropic growth of nanostructures provides a novel route for the synthesis of bifunctional particles with atomic-level control on selectivity …
Stabilizing A 22 Karat Nanogolden Cage, Q. Wang, Q. Sun, P. Jena
Stabilizing A 22 Karat Nanogolden Cage, Q. Wang, Q. Sun, P. Jena
Physics Publications
Since the discovery of C60 fullerene, considerable efforts have been devoted to find other elements with similar hollow cage structures. However, search for hollow metallic cages with a diameter similar to that of C60 fullerene has been elusive. We describe a procedure for the rational design of metallic cages by suitably choosing their size, composition, and charge state. A 22 karat nanogolden cage with a diameter of about 8.5 Å and consisting of 12 Al and 20 Au atoms is found to be metastable, which can be stabilized by embedding a Mn4 cluster. In contrast to bulk Mn, which is …
Photoadsorption And Photodesorption For Gan, M. Foussekis, A. A. Baski, Michael A. Reshchikov
Photoadsorption And Photodesorption For Gan, M. Foussekis, A. A. Baski, Michael A. Reshchikov
Physics Publications
The effect of an ambient environment on the surface photovoltage and photoluminescence observed for GaN is studied. In air ambient the upward band bending gradually increases under UVillumination and is explained by the photoinduced chemisorption of surface adsorbates. Specifically, the increase in negative surface charge is consistent with the transfer of electrons from surface states or bulk to oxygen species physisorbed at the GaNsurface. In contrast, the upward band bending gradually decreases in vacuum under UVillumination and can be explained by the photoinduced desorption of these species. The photoadsorption and photodesorption of negatively charged species cause the surface depletion region …
Functionalized Heterofullerenes For Hydrogen Storage, Qiang Sun, Qian Wang, Puru Jena
Functionalized Heterofullerenes For Hydrogen Storage, Qiang Sun, Qian Wang, Puru Jena
Physics Publications
Using density functional theory, we show that Li decorated B doped heterofullerene (Li12C48B12) has the following desired properties of a hydrogen storagematerial. (1) The Li atoms remain isolated. (2) Through charge transfer to electron deficient C48B12 heterofullerene, the Li atoms become positively charged. (3) Each Li atom is able to bind up to three H2molecules, which remain in molecular form, and the binding energies of successive H2molecules are in the range of 0.135–0.172 eV/H2, suitable for ambient temperature storage. (4) The gravimetric density reaches the 9 wt % limit necessary for applications in the mobile industry.
Mg-Doped Gan Nanostructures: Energetics, Magnetism, And H2 Adsorption, Qian Wang, Qiang Sun, Puru Jena, Yoshiyuki Kawazoe
Mg-Doped Gan Nanostructures: Energetics, Magnetism, And H2 Adsorption, Qian Wang, Qiang Sun, Puru Jena, Yoshiyuki Kawazoe
Physics Publications
Using density functional theory and generalized gradient approximation for exchange and correlation potential we show that Mg-doped GaN nanocages and nanotubes can be magnetic with Mg-contributed spins distributed over the neighboring N sites. Mg atoms show no tendency for clustering due to the positive charge residing on them; they can trap hydrogen in molecular form via the charge polarization mechanism. The binding energies of hydrogen lie in the range of 0.1–0.2 eV/H2, which are ideal for storage applications under ambient thermodynamic conditions.
Highly Efficient (Cs8v) Superatom-Based Spin-Polarizer, Haiying He, Ravindra Pandey, J. Ulises Reveles, Shiv N. Khanna, Shashi P. Karna
Highly Efficient (Cs8v) Superatom-Based Spin-Polarizer, Haiying He, Ravindra Pandey, J. Ulises Reveles, Shiv N. Khanna, Shashi P. Karna
Physics Publications
Quantum transport through molecules and the possibility to manipulate spin has generated tremendous excitement. Here, we demonstrate unusual spin transport through a molecule of twoCs8V magnetic superatoms. Calculations based on density functional theory and nonequilibrium Green’s function methods find a much higher current for the spin-down charge carriers relative to the spin-up carriers in the model Au–(Cs8V)–(Cs8V)–Au device system with almost 100% spin polarization, indicating a highly efficient spin polarizer. The new behavior is rooted in strong coupling of the localized magnetic core on V and the itinerant electrons of the Cs shell atoms leading to nearly full spin polarization.
Title Page, Preface
Journal of Mathematics and Science: Collaborative Explorations
No abstract provided.
Understanding Teacher Leadership In Middle School Mathematics: A Collaborative Research Effort, J. E. Pustejovsky, J. P. Spillane, R. M. Heaton, W. J. Lewis
Understanding Teacher Leadership In Middle School Mathematics: A Collaborative Research Effort, J. E. Pustejovsky, J. P. Spillane, R. M. Heaton, W. J. Lewis
Journal of Mathematics and Science: Collaborative Explorations
We report findings from a collaborative research effort designed to examine how teachers act as leaders in their schools. We find that teachers educated by the Math in the Middle Institute act as key sources of advice for colleagues within their schools while drawing support from a network consisting of other teachers in the program and university-level advisors. In addition to reporting on our findings, we reflect on our research process, noting some of the practical challenges involved, as well as some of the benefits of collaboration.
Building Middle-Level Mathematics Teachers' Capacities As Teachers And Leaders: The Math In The Middle Institute Partnership, R. M. Heaton, W. J. Lewis, W. M. Smith
Building Middle-Level Mathematics Teachers' Capacities As Teachers And Leaders: The Math In The Middle Institute Partnership, R. M. Heaton, W. J. Lewis, W. M. Smith
Journal of Mathematics and Science: Collaborative Explorations
This article describes professional development for middle-level mathematics teachers offered through the Math in the Middle Institute Partnership, a National Science Foundation-funded project to build teachers’ capacities to improve mathematics learning for all students. An overview of the project, including descriptions of its goals and curriculum are provided. Detailed descriptions of two mathematics courses and one pedagogy course are offered. The mathematics courses included here are the introductory course to the Math in the Middle Institute, as well as one of the final math courses of the Institute in which participants apply mathematical knowledge and processes to real-world problems. The …
Developing Leadership In A National Cohort Of Secondary Biology Teachers: Uses Of An On-Line Course Structure To Develop Geographically Distant Professional Learning Community, P. Balcerzak, V. May, B. Schaal
Developing Leadership In A National Cohort Of Secondary Biology Teachers: Uses Of An On-Line Course Structure To Develop Geographically Distant Professional Learning Community, P. Balcerzak, V. May, B. Schaal
Journal of Mathematics and Science: Collaborative Explorations
This report is a descriptive study of the role that on-line courses might have on the development of Professional Learning Communities (PLC’s) that support national leadership initiatives of participating high school biology teachers. The one hundred teachers involved in the Life Sciences for a Global Community (LSGC) Institute are expected not only to deepen their content knowledge, but also impact their district and state biology curricula. Additionally, the dispersion of Institute participants across the country presents a unique opportunity to develop, communicate. and implement a national coherent reform agenda. However, the geographic distance presents a barrier to collaborative design of …
The Impact Of Early Positive Results On A Mathematics And Science Partnership: The Experience Of The Institute For Chemistry Literacy Through Computational Science, K. S. Murray, M. A. Henry, M. C. Hogrebe
The Impact Of Early Positive Results On A Mathematics And Science Partnership: The Experience Of The Institute For Chemistry Literacy Through Computational Science, K. S. Murray, M. A. Henry, M. C. Hogrebe
Journal of Mathematics and Science: Collaborative Explorations
After one year of implementation, the Institute for Chemistry Literacy through Computational Science, an NSF Mathematics and Science Partnership Institute Project led by the University of Illinois at Urbana-Champaign’s Department of Chemistry, College of Medicine, and National Center for Supercomputing Applications, experienced statistically significant gains in chemistry content knowledge among students of the rural high school teachers participating in its intensive, year-round professional development course, compared to a control group. The project utilizes a two-cohort, delayed-treatment, random control trial, quasi-experimental research design with the second cohort entering treatment one year following the first. The three-year treatment includes intensive two-week summer …
The Penn Science Teacher Institute: A Proven Model, C. Blasie, J. Butler-Kahle
The Penn Science Teacher Institute: A Proven Model, C. Blasie, J. Butler-Kahle
Journal of Mathematics and Science: Collaborative Explorations
The University of Pennsylvania’s Master of Chemistry Education (MCE) program graduated five cohorts of approximately twenty teachers between 2002 and 2006. One year after the teachers in the last cohort earned their degrees, the Penn Science Teacher Institute (Penn STI) initiated a follow-up study to ascertain if the goals of the MCE program had been sustained. For example, were the teachers incorporating updated content knowledge into their lessons and were their students learning more chemistry? A total of seventy-four of the eighty-two graduates participated in some aspect of this study. Because baseline data were not available for the MCE teachers …
K-5 Mathematics Specialists' Teaching And Learning About Fractions, J. W. Whitenack, A. J. Ellington
K-5 Mathematics Specialists' Teaching And Learning About Fractions, J. W. Whitenack, A. J. Ellington
Journal of Mathematics and Science: Collaborative Explorations
This paper describes the fraction-based mathematical activities of two teachers who are part of 3 Mathematics Specialist preparation program. Their work with fractions is traced from two perspectives: 1) their interactions with students as they struggle with fraction concepts; and, 2) their personal journeys to develop deeper understandings of fractions as participants in the Rational Numbers course that is part of their degree program. Through their stories, we gain a better understanding of the complex nature of their work with students and how their participation in the Mathematics Specialist program helps support their work in the school buildings.
Virginia's Mathematics Specialist Institute Project: A Summary Of Evaluation Findings, P. S. Smith, M. Wickwire
Virginia's Mathematics Specialist Institute Project: A Summary Of Evaluation Findings, P. S. Smith, M. Wickwire
Journal of Mathematics and Science: Collaborative Explorations
No abstract provided.
The Impact Of The Lead Teacher Professional Learning Community Within The Rice University Mathematics Leadership Institute, J. Sack, N. Kamau
The Impact Of The Lead Teacher Professional Learning Community Within The Rice University Mathematics Leadership Institute, J. Sack, N. Kamau
Journal of Mathematics and Science: Collaborative Explorations
Now in its fourth year, Rice University’s Mathematics Leadership Institute (MLI) has developed over sixty high school mathematics Lead Teachers. We focus on how membership in MLI has impacted participant teachers’ professional lives. The Lead Teacher community that emerged during MLl’s first Summer Leadership Institute embodies the characteristics of a sustaining and coherent knowledge community where teachers are able to share their secret “stories of practice in safe places . . . in order to make their personal practical knowledge explicit to themselves and to others” [1]. This article includes stories of individual teachers who refused to sacrifice hours of …
Formulating A State Approach To Professional Development, R. E. Howard, S. Sarani, J. Woods
Formulating A State Approach To Professional Development, R. E. Howard, S. Sarani, J. Woods
Journal of Mathematics and Science: Collaborative Explorations
When viewed from the perspective of an entire state's needs, the challenges of designing professional development to meet the requirements of the federal No Child Left Behind legislation of 2001 are daunting. In Oklahoma, the concerns about delivering to rural and urban populations which contain a variety of underserved populations are further complicated by the differences in the way science and mathematics are structured as disciplines. We describe two model programs, one in science and one in mathematics, which take much different approaches. However, the programs have three common elements that make them highly successful. Each program engages teachers strongly, …
Mathematics Specialists Increasingly Appreciated And Sought, D. Blount, J. Singleton
Mathematics Specialists Increasingly Appreciated And Sought, D. Blount, J. Singleton
Journal of Mathematics and Science: Collaborative Explorations
No abstract provided.
Helping Kindergarteners Make Sense Of Numbers To 100, L. B. Jaslow, V. R. Jacobs
Helping Kindergarteners Make Sense Of Numbers To 100, L. B. Jaslow, V. R. Jacobs
Journal of Mathematics and Science: Collaborative Explorations
The authors share what was learned about kindergarteners' abilities to make sense of numbers to 100 when one of the authors, Linda Jaslow, took over a kindergarten class from February through the end of the school year. Through examples of how she engaged her students in nine weeks of problem solving and discussions focused on making sense of the number system, we provide evidence that the children grew substantially in their ability to count and show understanding when counting by 10's and using 10's during problem solving. Suggestions for tasks to promote continued growth are also provided. Throughout this teaching …
Understanding Elementary Teachers' Use Of Science Teaching Time: Lessons From The Big Sky Science Partnership, R. Jones, E. Swanson
Understanding Elementary Teachers' Use Of Science Teaching Time: Lessons From The Big Sky Science Partnership, R. Jones, E. Swanson
Journal of Mathematics and Science: Collaborative Explorations
No abstract provided.
Contents
Journal of Mathematics and Science: Collaborative Explorations
No abstract provided.
Let's Observe!, S. W. Brown
Let's Observe!, S. W. Brown
Journal of Mathematics and Science: Collaborative Explorations
Teaching the non-science major how to teach science is a challenge! No matter what science course is being taught, professors must model good teaching strategies that promote an inquiry approach that incorporates prior knowledge, connections, a social environment, relevance, and time to actively construct new understandings of scientific concepts.