Physical Sciences and Mathematics Commons^™

Numerical Investigation Of Impact Of Relative Humidity On Droplet Accumulation And Film Cooling, Luz Irene Bugarin

Open Access Theses & Dissertations

During the summer, high inlet temperatures affect the power output of gas turbine systems. Evaporative coolers have gained popularity as an inlet cooling method for these systems. Wet compression has been one of the common evaporative cooling methods implemented to increase power output of gas turbine systems due to its simple installation and low cost. This process involves injection of water droplets into the continuous phase of compressor to reduce the temperature of the flow entering the compressor and in turn increase the power output of the whole gas turbine system. This study focused on a single stage rotor-stator compressor …

Impacting Earthquake Science And Geoscience Education: Educational Programming To Earthquake Relocation, Tina Louise Carrick

Open Access Theses & Dissertations

This Dissertation is comprised of four studies: three related to research on geoscience education and another seismological study of the South Island of New Zealand. The geoscience education research is grounded in 10 years of data collection and its implications for best practices for recruitment and retention of underrepresented minority students into higher education in the geosciences. The seismological component contains results from the relocation of earthquakes from the 2009 Dusky Sound Mw 7.8 event, South Island, New Zealand.

In recent years, many have cited a major concern that U.S. is not producing enough STEM graduates to fit the forecasted …

Students’ Attitudes About Peer-Led Team Learning Workshops In General Chemistry: A Critical Incident Study, A.E. Dreyfuss, Janet Liou-Mark

Publications and Research

How would students respond to open-ended questions regarding their experiences with PLTL workshops? This paper will present the results of a two-semester qualitative study on how students view workshop in their introductory chemistry courses, using Brookfield’s (1995) Critical Incident Questionnaire (CIQ). The five questions probe what stands out in the affirmative and negative, using key words: engaged, distanced, affirmed, puzzled or confused, and surprising. Collecting key moments from students in workshop, after several weeks of meeting, allow a grounded sense of how students view the workshop experience.

Relative Permeability Of Homogenous-Wet And Mixed-Wet Porous Media As Determined By Pore-Scale Lattice Boltzmann Modeling, C. J. Landry, Z. T. Karpyn, O. Ayala

Engineering Technology Faculty Publications

We present a pore-scale study of two-phase relative permeability in homogenous-wet porous media, and porous media altered to a mixed-wet state. A Shan-Chen type multicomponent lattice Boltzmann (LB) model is employed to determine pore-scale fluid distributions and relative permeability. Mixed-wet states are created by altering the wettability of solid surfaces in contact with the nonwetting phase at the end of steady state simulation of initially homogenous-wet porous media. To ensure accurate representation of fluid-solid interfacial areas, we compare LB simulation results to experimental measurements of interfacial fluid-fluid and fluid-solid areas determined by X-ray computed microtomography imaging of water and oil …

Re-Analysis Of The World Data On The Emc Effect And Extrapolation To Nuclear Matter, Stacy E. Karthas

Honors Theses and Capstones

The EMC effect has been investigated by physicists over the past 30 years since it was discovered at CERN. This effect shows that the internal nucleon structure varies when in the nuclear medium. Data from SLAC E139 and JLab E03 103 were studied with the Coulomb correction and directly compared. The Coulomb distortion had a greater impact on the JLab data due to slightly lower energies and different kinematics. The EMC ratio was found to have a dependence on a kinematic variable, which was removed when Coulomb corrections were applied. The methodology was developed to apply Coulomb corrections, which had …

Forcing Mutual Coherence In Diode Laser Stacks, Jonathan R. Wurtz

Honors Theses and Capstones

This paper will discuss both theoretical and experimental attempts to improve the spatial beam quality of diode laser stacks using an external optical system. An overview and derivation of the mathematics of both the optical system and diode lasers will be discussed. The experimental setup will be presented, as well as the fundamental theoretical and experimental results that suggest the external optical system used for this thesis fails to improve the beam quality of a diode laser stack.

Carbon Farming In Relation To Western Australian Agriculture, Robert Sudmeyer, Jackson Parker, Tanmoy Nath, Ananda Ghose

Bulletins 4000 -

Carbon farming activities need to return multiple economic and environmental co-benefits to be attractive to land managers. This bulletin summarises concepts underlying carbon farming, how Australia accounts for greenhouse gas emissions and the potential for Western Australian land managers to participate in, and benefit from, carbon farming.

Design And Synthesis Of Porous Organic Frameworks For H2 And Ch4 Storage And For Selective Co2 Adsorption, Venkata Neti

Open Access Theses & Dissertations

Three new boronate-ester based covalent organic frameworks (CoPc-PorDBA, CoPc-BPDA and HHTP-PorDBA), an imine-linked porphyrin porous polymer (CuPor-BPDC) and imine and benzothiazole based porous polymers (IBTP), and a triazole based phthalocyanine "click" polymer (Pc-POP) were synthesized. The CoPc-PorDBA and CoPc-BPDA COFs exhibited high BET surface areas (1087, 1315 m2 g-1, respectively) whereas HHTP-PorDBA showed a low BET surface area of 205 m2 g-1. The H2 storage capacities of CoPc-BPDA and CoPc-PorDBA range between 0.8-1.2wt% at 77K, 1bar and the CH4 storage capacities range between 0.4-0.8wt% at 298K, 1bar. These materials also had good thermal stabilities up to 350° C. The BET …

Three‐Dimensional Brain Mri For Dbs Patients Within Ultra‐Low Radiofrequency Power Limits, Subhendra N. Sarkar, Efstathios Papavassiliou, David Hackney, David Alsop, Ananth Madhuranthakam, Ludy Shih, Reed Busse, Susan Laruche, Rafeeque Bhadelia

Publications and Research

Background: For patients with deep brain stimulators (DBS), local absorbed radiofrequency (RF) power is unknown and is much higher than what the system estimates. We developed a comprehensive, highquality brain magnetic resonance imaging (MRI) protocol for DBS patients utilizing three-dimensional (3D) magnetic resonance sequences at very low RF power. Methods: Six patients with DBS were imaged (10 sessions) using a transmit/receive head coil at 1.5 Tesla with modified 3D sequences within ultra-low specific absorption rate (SAR) limits (0.1 W/kg) using T2, fast fluid-attenuated inversion recovery (FLAIR) and T1- weighted image contrast. Tissue signal and tissue contrast from the low-SAR images …

Geoneutrino Production Of The Northern Black Hills, South Dakota, United States Of America, Eric Eric Zimney

Theses and Dissertations

Current neutrino observatories operate underground to isolate the detector from cosmic rays and background radiation. However, background radiation from local sources has yet to be accounted for. Current models for neutrino contributions from terrestrial rocks are formulated from bulk compositional estimates of the whole Earth. To better understand local background radiation from geologic sources surfaces rocks were collected throughout the area surrounding the Homestake Mine, South Dakota, home of the Sanford Underground Research Laboratory. The surface rocks were analyzed for radioactivity and neutrino luminosity, producing heat maps indicating the levels of neutrino production throughout the area. The area around the …

Erratum: Measurement Of D* ± Production In Deep Inelastic Scattering At Hera (Journal Of High Energy Physics (2013) (097)), H. Abramowicz, I. Abt, L. Adamczyk, M. Adamus, R. Aggarwal, S. Antonelli, P. Antonioli, A. Antonov, M. Arneodo, O. Arslan, V. Aushev, Y. Aushev, O. Bachynska, A. Bamberger, A. N. Barakbaev, G. Barbagli, G. Bari, F. Barreiro, N. Bartosik, D. Bartsch, M. Basile, O. Behnke, J. Behr, U. Behrens, L. Bellagamba, A. Bertolin, S. Bhadra, M. Bindi, C. Blohm, V. Bokhonov, T. Bold, Margarita C. K. Mattingly

Faculty Publications

No abstract provided.

Calcite Dissolution Under Turbulent Flow Conditions: A Remaining Conundrum, Matthew D. Covington

Geosciences Faculty Publications and Presentations

A significant body of experimental and theoretical work has examined the dissolution rates of calcite, and other carbonate minerals, under varying chemical and hydrodynamic conditions (see Morse & Arvidson (2002) for a comprehensive review). The relationships derived from this work have been applied extensively to the development of mechanistic models of speleogenesis (e.g. Dreybrodt 1996; Dreybrodt et al. 2005; Birk et al. 2005; Rehrl et al. 2008; Kaufmann 2009; Szymczak & Ladd 2011). However, the primary focus of these models has been on the early stages of cave formation, with less attention toward the later stages of cave evolution and …

Green Siting For Green Energy, Amy Wilson Morris, Jessica Owley, Emily Capello

Journal Articles

No abstract provided.

Visible-Light Photocatalyzed Cross-Linking Of Diacetylene Ligands By Quantum Dots To Improve Their Aqueous Colloidal Stability, Marion G. Götz, Hiroko Takeuchi, Matthew J. Goldfogel, Julia M. Warren, Brandon D. Fennel, Colin D. Heyes

Chemistry & Biochemistry Faculty Publications and Presentations

Ligand cross-linking is known to improve the colloidal stability of nanoparticles, particularly in aqueous solutions. However, most cross-linking is performed chemically, in which it is difficult to limit interparticle cross-linking, unless performed at low concentrations. Photochemical cross-linking is a promising approach but usually requires ultraviolet (UV) light to initiate. Using such high-energy photons can be harmful to systems in which the ligand–nanoparticle bond is fairly weak, as is the case for the commonly used semiconductor quantum dots (QDs). Here, we introduce a novel approach to cross-link thiolated ligands on QDs by utilizing the photocatalytic activity of QDs upon absorbing visible …

Western Australian Graduate Diploma Of Education (Primary) Students' Perceptions Of Sustainability, Judith Clare Odgaard

Theses: Doctorates and Masters

In late 2011, the researcher investigated a cohort of Western Australian (WA) Graduate Diploma of Education Primary (GDE-P) students’ perceptions of Sustainability across a broad range of biophysical/natural, social and cultural, economic and political spheres. The study occurred during the seventh year of UNESCO’s Decade of Education for Sustainability Development, and when Sustainability Education became one of three cross-curriculum priorities of the new Australian Curriculum. Importantly, the students’ perceptions were interpreted during the context of the Post Global Financial Crisis and after Julia Gillard replaced Kevin Rudd as the Labor Prime Minister. The intense political context was often supported by …

Bio-Inspired Surface Engineering For Hydrophobicity, Hua Guo

Theses: Doctorates and Masters

Highly evolved, efficient and sophisticated biological systems can be used as models for scientific innovations. This research explored specific surface structures on plant leaves with respect to their hydrophobicity in the context of the often arid Australian climate. The relationships between leaf surface structures and their hydrophobicity could inform the making of artificial surfaces with specially designed hydrophobicity.

Moderate hydrophobicity and strong surface adhesion were discovered on many study plant leaves. Scanning Electron Microscopy (SEM) revealed that their surface morphologies could be categorized into four groups while their water-repellent mechanisms were considered at an individual species level. Specifically, physical models …

A Preliminary Investigation Of The Potential Effects Of The Invasive Mozambique Tilapia Oreochromis Mossambicus On The Native Fish Assemblages Of Lake Macleod, Western Australia, Hannah Cameron-Caluori

Theses: Doctorates and Masters

As one of the major threats to biodiversity in aquatic systems, invasive species can alter the structure and function of a community, often through habitat and resource competition, and/or direct predation. This study aims to determine if invasive tilapia (Oreochromis mossambicus) is likely to have an effect on the native fish communities of Lake MacLeod, a unique and important inland, saline lake system in north-western Western Australia, through competition for key resources, namely habitat and food sources. Seven study sites were selected within the Northern Ponds of Lake MacLeod, from which fish abundances were assessed in three habitats …

Visible Light Mediated Intermolecular [3 + 2] Annulation Of Cyclopropylanilines With Alkynes, Theresa H. Nguyen, Soumitra Maity, Nan Zheng

Chemistry & Biochemistry Faculty Publications and Presentations

Intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes is realized using visible light photoredox catalysis, yielding a variety of cyclic allylic amines in fair to good yields. This method exhibits significant group tolerance particularly with heterocycles. It can also be used to prepare complex heterocycles such as fused indolines.

Evaluating N-Benzylgalactonoamidines As Putative Transition State Analogs For Β-Galactoside Hydrolysis, Qui-Hua Fan, Susanne Striegler, Rebekah Langston, James Barnett

Chemistry & Biochemistry Faculty Publications and Presentations

Experimental evidence is provided for p-methylbenzyl-D-galactonoamidine to function as a true transition state analog for the enzymatic hydrolysis of aryl-β-D-galactopyranosides by β-galactosidase (A. oryzae). The compound exhibits inhibition constants in the low nanomolar concentration range (12–56 nM) for a selection of substrates. Along these lines, a streamlined synthetic method based on phase-transfer catalysis was optimized to afford the required variety of new aryl-β-D-galactopyranosides. Last, the stability of the galactonoamidines under the assay conditions was confirmed.

Ratings Lead You To The Product, Reviews Help You Clinch It? The Dynamics And Impact Of Online Review Sentiments On Products Sales, Nan Hu, Noi Sian Koh, Srinivas K. Reddy

Research Collection Lee Kong Chian School Of Business

It is generally assumed that ratings are a numeric representation of text sentiments and their valences are consistent. This however may not always be true. Using a panel of data on over 4000 books from Amazon.com, we develop a multiple equation model to examine the inter-relationships between ratings, sentiments, and sales. We find that ratings do not have a significant direct impact on sales but have an indirect impact through sentiments. Sentiments, however, have a direct significant impact on sales. Our findings also indicate that the two most accessible types of reviews - most helpful and most recent - play …

A Decision Making Tool For Sustainable Design In Construction, Enda Collins

Theses

This report defines sustainability and sustainable development before any research is carried out. This is necessary so that the research carried out further in the report makes sense and there is a reason for including such items in this report. The need for this project and what the project aims to achieve is also highlighted in the introduction of this report.

Sustainability is made up of three equal parts; social, economic and environmental. This report goes through each item and gives examples of each type of development. Having discussed sustainability in a broad sense the report then focuses on Legislation …

Achieving ‘Net Zero Energy’ Performance Through Retrofitting Of Residential Buildings In Ireland., M. Alan Costello

Theses

A Net Zero Energy Building (nZEB) is a residential or commercial building that consumes net zero energy over a set period of time, usually taken as one year. In short, for every unit of energy the building consumes over a year, it must generate a unit of energy to maintain an overall net balance. This is achieved by reducing the operational energy usage to a very low level through energy efficient design, and then providing renewable generation technologies on site to cater for the remaining energy demand.

Energy use in all sectors of society is under scrutiny at present, largely …

Higher Order Mode Damping In Superconducting Spoke Cavities, C. S. Hopper, J. R. Delayen

Physics Faculty Publications

Parasitic higher order modes (HOMs) can be severely detrimental to the performance of superconducting cavities. For this reason, the mode spectrum and beam coupling strength must be examined in detail to determine which modes must be damped. One advantage of the spoke cavity geometry is that couplers can be placed on the outer body of the cavity rather than in the beam line space. We present an overview of the HOM properties of spoke cavities and methods for suppressing the most harmful ones.

Employing Twin Crabbing Cavities To Address Variable Transverse Coupling Of Beams In The Meic, A. Castilla, V. S. Morozov, T. Satogata, J. R. Delayen

Physics Faculty Publications

The design strategy of the Medium Energy Electron-Ion Collider (MEIC) at Jefferson Lab contemplates both matching of the emittance aspect ratios and a 50 mrad crossing angle along with crab crossing scheme for both electron and ion beams over the energy range (√s=20-70 GeV) to achieve high luminosities at the interaction points (IPs). However, the desired locations for placing the crabbing cavities may include regions where the transverse degrees of freedom of the beams are coupled with variable coupling strength that depends on the collider rings’ magnetic elements (solenoids and skew quadrupoles). In this work we explore the feasibility of …

Progress On The Interaction Region Design And Detector Integration At Jlab's Meic, V. S. Morozov, P. Brindza, A. Camsonne, Ya S. Derbenev, R. Ent, D. Gaskell, F. Lin, P. Nadel-Turonski, M. Ungaro, Y. Zhang, C. E. Hyde, K. Park, M. Sullivan, Z. W. Zhao

Physics Faculty Publications

One of the unique features of JLab's Medium-energy Electron-Ion Collider (MEIC) is a full-acceptance detector with a dedicated, small-angle, high-resolution detection system, capable of covering a wide range of momenta (and charge-to-mass ratios) with respect to the original ion beam to enable access to new physics. We present an interaction region design developed with close integration of the detection and beam dynamical aspects. The dynamical aspect of the design rests on a symmetry-based concept for compensation of non-linear effects. The optics and geometry have been optimized to accommodate the detection requirements and to ensure the interaction region's modularity for ease …

Fabrication And Measurements Of 500 Mhz Superconducting Double Spoke Cavity, Hyekyoung Park, C. S. Hopper, J. R. Delayen

Physics Faculty Publications

The 500 MHz double spoke cavity has been designed for a high velocity application such as a compact electron accelerator at Center for Accelerator Science at Old Dominion University and is being built at Jefferson Lab. The geometry specific to the double spoke cavity requires a variety of tooling and fixtures. Also a number of joints are expected to make it difficult to maintain the geometric deviation from the design minimal. This paper will report the fabrication technique, resulting tolerance from the design, and comparison between the measurements and simulations.

Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √ S = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, S. Bültmann, I. Koralt, D. Plyku, Star Collaboration

Physics Faculty Publications

The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8<η/c and is found to agree with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry A_LL is measured in the same pseudorapidity range and spans a range of Bjorken-x down to x≈0.01. The measured A_LL is consistent with model predictions for varying degrees of gluon polarization. The parity-violating asymmetry A_L is also measured and found to be consistent with zero. The transverse single-spin asymmetry AN is measured over a previously unexplored kinematic range in Feynman-x and P_T. Such measurements may aid our understanding of the onset and kinematic dependence of the large asymmetries observed …

Precision Measurements Of G¹ Of The Proton And The Deuteron With 6 Gev Electrons, Y. Prok, K. P. Adhikari, D. Adikaram, M. J. Amaryan, G. E. Dodge, N. Guler, A. Klein, S. Koirala, S. E. Kuhn, Clas Collaboration

Physics Faculty Publications

The inclusive polarized structure functions of the proton and deuteron, g^p₁ and g^d₁ , were measured with high statistical precision using polarized 6 GeV electrons incident on a polarized ammonia target in Hall B at Jefferson Laboratory. Electrons scattered at laboratory angles between 18 and 45 degrees were detected using the CEBAF Large Acceptance Spectrometer (CLAS). For the usual deep inelastic region kinematics, Q² > 1 GeV² and the final-state invariant mass W >2 GeV, the ratio of polarized to unpolarized structure functions g₁/F₁ is found to be nearly independent of Q …

High Precision Determination Of The Q² Evolution Of The Bjorken Sum, A. Deur, Y. Prok, V. Burkert, D. Crabb, F. X. Girod, K. A. Griffioen, N. Guler, S. E. Kuhn, N. Kvaltine

Physics Faculty Publications

We present a significantly improved determination of the Bjorken sum for 0.6 ≤ Q² ≤ 4.8 GeV² using precise new g^p₁ and g^d₁ data taken with the CLAS detector at Jefferson Lab. A higher-twist analysis of the Q² dependence of the Bjorken sum yields the twist-4 coefficient f ^p-n₂= -0.064 ± 0.009 ± ^0.032 _0.036. This leads to the color polarizabilities χ ^p-n _E= -0.032 ± 0.024 and χ^p-n_B= 0.032 ± 0.013. The strong force coupling is determined to be α ^MS_S (M²_{Z …}

Φ-Meson Photoproduction On Hydrogen In The Neutral Decay Mode, H. Seraydaryan, M. J. Amaryan, G. Gavalian, L. Weinstein, K. P. Adhikari, D. Adikaram, R. P. Bennett, S. Bültmann, N. Guler, C. E. Hyde, S. Koirala, S. E. Kuhn, L. B. Weinstein

Physics Faculty Publications

We report the first measurement of the photoproduction cross section of the ϕ meson in its neutral decay mode in the reaction γp→pϕ(K_SK_L) . The experiment was performed with a tagged photon beam of energy 1.6 ≤ E_γ ≤ 3.6 GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The pϕ final state is identified via reconstruction of K_S in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction γp→pK_SX to be K_L. …