Digital Commons Network^™

Promoting Vocabulary Knoweldge In Inclusive Science Classrooms: Comparison Of Instructional Methods, Matthew Love

UNLV Theses, Dissertations, Professional Papers, and Capstones

A sustained trend in the overall enrollment in the United States has seen classrooms reflect more student diversity. This diversity has included increased rates of participation in general education classrooms from both students from culturally and linguistically diverse backgrounds and students with disabilities. While the increase in student diversity in general education classrooms is certainly a positive step in increasing inclusive education, shifting student demographics have presented teachers with new and evolving instructional challenges. The diverse academic, cultural, and linguistic backgrounds students represent also come to characterize the unique learning needs teachers should address. This is particularly true in science, …

Crystallographic Exploration Of Fundamental Technetium Species At Nonambient Conditions, Daniel S. Mast

UNLV Theses, Dissertations, Professional Papers, and Capstones

The study of mater under extreme conditions has yielded fascinating insight into the physical and chemical nature of materials that under more modest conditions are considered mundane but have quite unusual properties when under pressure. Examples of this are the lightest of elements found in the first two rows and in the heaviest elements of the lanthanide and actinide series. Pure elements, though the simplest possible chemical systems, have proven to be among the most complex and interesting. Technetium metal is a simple HCP transition metal that, due to its half-filled d-shell, has a rich chemistry and an important place …

Science Identity And Underrepresented Minority Stem Organizations, Schetema Nealy

UNLV Theses, Dissertations, Professional Papers, and Capstones

President Obama indicated that there are twice as many science and technology jobs available in the U.S. as there are workers for those jobs (Office of the Secretary, 2013). To fulfill the need for more scientists and engineers, there must be increased educational support for the nation’s underrepresented minority (URM) science, technology, engineering, and mathematics (STEM) students. URM STEM organizations, such as the National Society of Black Engineers and other URM student-oriented organizations that provide academic and career resources, are widely used on college and university campuses across the nation to support these students both academically and professionally. Future developments …

Community Detection And Ranking In Big Data Graphs, Matin Pirouz Nia

UNLV Theses, Dissertations, Professional Papers, and Capstones

Community structures and relation patterns, and ranking them for social networks provide us with great knowledge about the network. A community is defined by determining a lower density of relations between groups comparing to higher density among every group. Such knowledge can be utilized for grouping similar, yet distinct, nodes with applications in health, marketing, and many more. The ever-growing variety of social networks necessitates detection of minute and scattered communities, which are important problems across different research fields including biology, social studies, physics, etc. As a result, analyzing complex networks has become very popular among researchers in academia and …

Dissolution Rates Of Allophane, Fe-Allophane, And Hisingerite And Implications For Aqueous Alteration On Mars And In Potential Returned Martian Samples, S. J. Ralston

UNLV Theses, Dissertations, Professional Papers, and Capstones

Recent measurements from Mars document X-ray amorphous/nano-crystalline materials in multiple locations across the planet. However, despite their prevalence, little is known about these materials or what their presence implies for the history of Mars. The amorphous component of the martian soil in Gale Crater has an X-ray diffraction pattern that can be partially fit with allophane (approximately Al2O3•(SiO2)1.3-2•(H2O)2.5-3), as well as low-temperature water release consistent with allophane. The chemical data from Gale Crater suggest that other silicate phases similar to allophane, such as Fe-substituted allophane (here, approximately (Fe2O3)0.01(Al2O3)0.99(SiO2)2•3H2O) and hisingerite (approximately Fe3+2Si2O5(OH)4•(H2O)), may also be present. In order to investigate …

A Descriptive Exploration Of A Self-Directed Professional Development Approach, Derek R. Riddle

UNLV Theses, Dissertations, Professional Papers, and Capstones

Teachers, who are deemed the greatest in-school factor of student success, are often invited or mandated to engage in some form of professional development (PD) to continue in improving their practice. However, an empirical understanding of how teachers learn from PD offerings remains elusive and incomplete. Often teachers report not learning from the models where they have little autonomy. While there is small body of research on teacher-driven models, there is a lack of sufficient evidence on whether these models enhance teacher learning and ultimately their practice. Therefore, this study employed grounded theory methods coupled with a descriptive research approach …

Conformal Mapping Improvement Of The Boundary Element Method Solution For Underground Water Flow In A Domain With A Very Singular Boundary, Megan Romero

UNLV Theses, Dissertations, Professional Papers, and Capstones

Numerical solutions using a Boundary Element Method (BEM) for a confined flow in a very singular finite domain are developed. Typically, in scientific journal publications, authors avoid domains with many and more malignant singularities due to the extremely big and difficult to estimate errors in the numerical calculations. Using exact Conformal Mapping solutions for simplified domains with the same singularity as in the original domain, this problem can be solved numerically with improvements introduced by Conformal Mapping solutions. Firstly, to experiment with improving the BEM solution by Conformal Mapping, a domain inside a rectangle is considered. The exact solution inside …

Social Media Influencer Endorsement And Events: An Integrated Framework Of Congruence, Jie Sun

UNLV Theses, Dissertations, Professional Papers, and Capstones

In today’s digital world, marketing practitioners have increasingly started to reach out to their audiences by integrating social media influencer (SMI) into their marketing plans. The purpose of this dissertation was to explore the factors influencing SMI endorsement effectiveness in the context of event. Based on relevant theories (congruity theory, match-up hypothesis model, self-congruity theory, and vicarious self-perception) and a thorough review of existing literature in the SMI endorsement, the present study developed an integrative research model which included follower’s prior attitude toward SMI, attitude toward the event, pass-on behavior intention, event participation intention, SMI-event congruence, event-follower congruence, and SMI-followers …

Secure Device And Knowledge Discovery In Internet Of Things, Shahab Taregh Tayeb

UNLV Theses, Dissertations, Professional Papers, and Capstones

With the ever-growing adoption of Internet of Things (IoT), there is continued development and deployment of new nodes with various capabilities and services. Such heterogeneity introduces complexity and a significant need for neighbor service discovery frameworks. Because the types of services available are orders of magnitude more than pre-IoT era, researchers need new techniques to accurately discover not only the topologies and adjacencies but also the capability of other nodes and neighbors. Device discovery is usually the first task to be performed, immediately after deployment, as it enables communications, scheduling, and channel estimation. The existing discovery mechanisms do not consider …

Investigations Into The Airside Cooling Of A Heat Exchanger, David Vallet

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this study we investigate the air-side cooling of a flat-plate fin and tube heat transfer condenser with numerical simulations. A new design is proposed which utilises vortex generators to direct the flow in such a way as to remove some of the stagnant heated air that collects in the wake of the pipes. A comparative study of the proposed design and a standard tube and fin condenser is conducted by varying the air side entrance velocities. The Shear Stress Tension, SST $\kappa - \omega$ 2-equation turbulent model is used to solve the RANS model in ANSYS Fluent 18. The …

The Effect Of Titanium Dioxide On Nucleate Pool Boiling Using An Aluminum Substrate, Kevin Yim

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nucleate pool boiling is a mode of pool boiling that tends to transfer heat more efficiently than the other modes of pool boiling. Many studies have been done to augment the heat transferred during nucleate pool boiling. Various methods of heat transfer augmentation in

boiling can be performed through active treatments (mechanical aids, surface/fluid vibrations, etc.) or passive treatments (functional coating, surface roughening, etc.). This study focuses primarily on a passive treatment, specifically TiO2 coating, which involves testing a substrate coated with TiO2 using NeverWetTM base coating as a coupling agent and coated using a method outlined by Wu et …

Study Of Blockchain-As-A-Service Systems With A Case Study Of Hyperledger Fabric Implementation On Kubernetes, Aniket Jalinder Yewale

UNLV Theses, Dissertations, Professional Papers, and Capstones

Blockchain is a shared, immutable, decentralized ledger to record the transaction history. Blockchain technology has changed the world, changed the way we do the business. It has transformed the commerce across every industry, which may be supply chain, IoT, financial services, banking, healthcare, agriculture and many more. It had introduced a new way of transactional applications that bring trust, security, transparency and accountability.

To develop any blockchain use case, the main task is to develop an environment for creating and deploying the application. In our case, we created an environment on IBM Cloud Kubernetes service using Kubernetes, a container orchestration …

Collisional Quenching Of Highly Excited H2 Due To H2 Collisions, Yier Wan, B. H. Yang, P. C. Stancil, Balakrishnan Naduvalath, Nikhil J. Parekh, R. C. Forrey

Chemistry and Biochemistry Faculty Research

Rate coefficients for pure rotational quenching in H2(ν 1 = 0, j 1) + H2(ν 2 = 0, j 2) collisions from initial levels of j 1 = 2–31 (j 2 = 0 or 1) to all lower rotational levels are presented. We carried out extensive quantum mechanical close-coupling calculations based on a recently published H2–H2 potential energy surface (PES) developed by Patkowski et al. that has been demonstrated to be more reliable than previous work. Rotational transition cross sections with initial levels of j 1 = 2–14, 18, 19, 24, and 25 were computed for energies ranging from 10−6 …

Gamma-Ray Burst/Supernova Associations: Energy Partition And The Case Of A Magnetar Central Engine, Hon-Jun Lü, Lin Lan, Bing Zhang, En-Wei Liang, David Alexander Kann, Shen-Shi Du, Jun Shen

Physics & Astronomy Faculty Research

The favored progenitor model for Gamma-ray Bursts (GRBs) with Supernova (SN) association is the core collapse of massive stars. One possible outcome of such a collapse is a rapidly spinning, strongly magnetized neutron star ("magnetar"). We systematically analyze the multi-wavelength data of GRB/SN associations detected by several instruments before 2017 June. Twenty GRB/SN systems have been confirmed via direct spectroscopic evidence or a clear light curve bump, as well as some spectroscopic evidence resembling a GRB-SN. We derive/collect the basic physical parameters of the GRBs and the SNe, and look for correlations among these parameters. We find that the peak …

Systematic Mischaracterization Of Exoplanetary System Dynamical Histories From A Model Degeneracy Near Mean-Motion Resonance, John H. Boisvert, Benjamin E. Nelson, Jason H. Steffen

Physics & Astronomy Faculty Research

There is a degeneracy in the radial velocity exoplanet signal between a single planet on an eccentric orbit and a two-planet system with a period ratio of 2:1. This degeneracy could lead to misunderstandings of the dynamical histories of planetary systems as well as measurements of planetary abundances if the correct architecture is not established. We constrain the rate of mischaracterization by analysing a sample of 60 non-transiting, radial velocity systems orbiting main-sequence stars from the NASA Exoplanet Archive (NASA Archive) using a new Bayesian model comparison pipeline. We find that 15 systems (25 per cent of our sample) show …

Mining Association Rules For Low-Frequency Itemsets, Jimmy Ming-Tai Wu, Justin Zhan, Sanket Chobe

Computer Science Faculty Research

High utility itemset mining has become an important and critical operation in the Data Mining field. High utility itemset mining generates more profitable itemsets and the association among these itemsets, to make business decisions and strategies. Although, high utility is important, it is not the sole measure to decide efficient business strategies such as discount offers. It is very important to consider the pattern of itemsets based on the frequency as well as utility to predict more profitable itemsets. For example, in a supermarket or restaurant, beverages like champagne or wine might generate high utility (profit), but also sell less …

Pressure‐Tuneable Visible‐Range Band Gap In The Ionic Spinel Tin Nitride, John S. C. Kearney, Miglė Graužinytė, Dean Smith, Daniel Sneed, Christian Childs, Jasmine Hinton, Changyong Park, Jesse S. Smith, Eunja Kim, Samuel D. S. Fitch, Andrew L. Hector, Chris J. Pickard, José A, Flores-Livas, Ashkan Salamat

Physics & Astronomy Faculty Research

The application of pressure allows systematic tuning of the charge density of a material cleanly, that is, without changes to the chemical composition via dopants, and exploratory high‐pressure experiments can inform the design of bulk syntheses of materials that benefit from their properties under compression. The electronic and structural response of semiconducting tin nitride Sn3N4 under compression is now reported. A continuous opening of the optical band gap was observed from 1.3 eV to 3.0 eV over a range of 100 GPa, a 540 nm blue‐shift spanning the entire visible spectrum. The pressure‐mediated band gap opening is general to this …

Thing-Makers, Tool Freaks And Prototypers: How The Whole Earth Catalog’S Optimistic Message Reinvented The Environmental Movement In 1968, Andy Kirk

History Faculty Research

In the fall of 1968 a Stanford-trained biologist, organizer of the legendary Trips Festival and Merry Prankster named Stewart Brand published the first Whole Earth Catalog. Between 1968 and 1972, the Catalog reached millions of readers and won the National Book Award. The title and iconic cover image of this counterculture classic celebrated the first publicly released NASA photographs showing the whole planet Earth from space. These images profoundly changed the way humans thought about the environment. And the Catalog played an important role in that change.

A Novel Deep Learning Framework For Internal Gross Target Volume Definition From 4d Computed Tomography Of Lung Cancer Patients, Xiadong Li, Ziheng Deng, Qinghua Deng, Lidan Zhang, Tianye Niu, Yu Kuang

Health Physics and Diagnostic Sciences Faculty Research

In this paper, we study the reliability of a novel deep learning framework for internal gross target volume (IGTV) delineation from four-dimensional computed tomography (4DCT), which is applied to patients with lung cancer treated by Stereotactic Body Radiation Therapy (SBRT). 77 patients who underwent SBRT followed by 4DCT scans were incorporated in a retrospective study. The IGTV_DL was delineated using a novel deep machine learning algorithm with a linear exhaustive optimal combination framework, for the purpose of comparison, three other IGTVs base on common methods was also delineated, we compared the relative volume difference (RVI), matching index (MI) and encompassment …

White Dwarf Pollution By Asteroids From Secular Resonances, Jeremy L. Smallwood, Rebecca G. Martin, Mario Livio, Stephen H. Lubow

Physics & Astronomy Faculty Research

In the past few decades, observations have revealed signatures of metals polluting the atmospheres of white dwarfs. The diffusion time-scale for metals to sink from the atmosphere of a white dwarf is of the order of days for a hydrogen-dominated atmosphere. Thus, there must be a continuous supply of metal-rich material accreting onto these white dwarfs. We investigate the role of secular resonances that excite the eccentricity of asteroids allowing them to reach star-grazing orbits leading them to tidal disruption and the formation of a debris disc. Changes in the planetary system during the evolution of the star lead to …

What Powered The Optical Transient At2017gfo Associated With Gw170817?, Shao-Ze Li, Liang-Duan Liu, Yun-Wei Yu, Bing Zhang

Physics & Astronomy Faculty Research

The groundbreaking discovery of the optical transient AT2017gfo associated with GW170817 opens a unique opportunity to study the physics of double neutron star (NS) mergers. We argue that the standard interpretation of AT2017gfo as being powered by radioactive decay of r-process elements faces the challenge of simultaneously accounting for the peak luminosity and peak time of the event, as it is not easy to achieve the required high mass, and especially the low opacity of the ejecta required to fit the data. A plausible solution would be to invoke an additional energy source, which is probably provided by the merger …

Covalency Is Frustrating: La2sn2o7 And The Nature Of Bonding In Pyrochlores Under High Pressure–Temperature Conditions, Christian Childs, Keith V. Lawler, Andrew L. Hector, Sylvain Petitgirard, Ori Noked, Jesse S. Smith, Dominik Daisenberger, Lucile Bezacier, Marek Jura, Chris J. Pickard, Ashkan Salamat

Chemistry and Biochemistry Faculty Research

Natural specimens of the pyrochlore (A2B2O7) compounds have been found to retain foreign actinide impurities within their parent framework, undergoing metamictization to a fully amorphous state. The response to radionuclide decay identifies pyrochlore systems with having high radiation tolerance and tailored use in radioactive waste applications and radionuclide sequestration. High pressure is a powerful pathway to high density states and amorphization with parallels to radiation-induced processes. Here, La2Sn2O7 is evaluated under extreme conditions via the combination of laser heating in a diamond anvil cell with X-ray diffraction and Raman spectroscopy. The measurements are supported by ab initio random structure searching …

Christianity And Gambling: An Introduction, Massimo Leone

Occasional Papers

Religions hold complex relations with games and, in particular, with gambling. The article focuses on Christianity. On the one hand, the history of this religion shows a tendency to condemn games as source of distraction from spiritual rectitude and to stigmatize gambling, above all, as opening to metaphysical randomness and, as a consequence, as challenge to the idea of divine omniscience. On the other hand, Christianity has also sought to reinterpret games, and even gambling, as possible occasion for moral improvement and as useful distraction from the hardship of monastic life. A theological perspective that reaches its peak in Thomas …

Topological Nodal Line Semimetal In An Orthorhombic Graphene Network Structure, Jian-Tao Wang, Changfeng Chen, Yoshiyuki Kawazoe

Physics & Astronomy Faculty Research

Topological semimetals are a fascinating class of quantum materials that possess extraordinary electronic and transport properties. These materials have attracted great interest in recent years for their fundamental significance and potential device applications. Currently a major focus in this research field is to theoretically explore and predict and experimentally verify and realize material systems that exhibit a rich variety of topological semimetallic behavior, which would allow a comprehensive characterization of the intriguing properties and a full understanding of the underlying mechanisms. In this paper, we report on ab initio calculations that identify a carbon allotrope with simple orthorhombic crystal structure …

Polar Alignment Of A Protoplanetary Disc Around An Eccentric Binary - Ii. Effect Of Binary And Disc Parameters, Rebecca G. Martin, Stephen H. Lubow

Physics & Astronomy Faculty Research

In a recent paper Martin & Lubow showed that a circumbinary disc around an eccentric binary can undergo damped nodal oscillations that lead to the polar (perpendicular) alignment of the disc relative to the binary orbit. The disc angular momentum vector aligns to the eccentricity vector of the binary. We explore the robustness of this mechanism for a low-mass disc (0.001 of the binary mass) and its dependence on system parameters by means of hydrodynamic disc simulations. We describe how the evolution depends upon the disc viscosity, temperature, size, binary mass ratio, orbital eccentricity, and inclination. We compare results with …

The Eccentric Cavity, Triple Rings, Two-Armed Spirals, And Double Clumps Of The Mwc 758 Disk, Ruobing Dong, Sheng-Yuan Liu, Josh Eisner, Sean Andrews, Jeffrey Fung, Zhauhuan Zhu, Eugene Chiang, Jun Hashimoto, Hauyu Baobab Liu, Simon Casassus, Thomas Esposito, Yasuhiro Hasegawa, Takayuki Muto, Yaroslav Pavlyuchenkov, David Wilner, Eiji Akiyama, Motohide Tamura, John Wisniewski

Physics & Astronomy Faculty Research

Spatially resolved structures in protoplanetary disks hint at unseen planets. Previous imaging observations of the transitional disk around MWC 758 revealed an inner cavity, a ring-like outer disk, emission clumps, and spiral arms, all possibly generated by companions. We present ALMA dust continuum observations of MWC 758 at 0.87 mm wavelength with 43 × 39 mas angular resolution (6.9 × 6.2 au) and 20 μJy beam−1 rms. The central submillimeter emission cavity is revealed to be eccentric; once deprojected, its outer edge can be well fitted by an ellipse with an eccentricity of 0.1 and one focus on the star. …

Relationship Between Ocean-Atmospheric Climate Variables And Regional Streamflow Of The Conterminous United States, Swastik Bhandari, Ajay Kalra, Kazi Tamaddun, Sajjad Ahmad

Civil and Environmental Engineering and Construction Faculty Research

Understanding the interconnections between oceanic-atmospheric climate variables and regional streamflow of the conterminous United States may aid in improving regional long lead-time streamflow forecasting. The current research evaluates the time-lagged relationship between streamflow of six geographical regions defined from National Climate Assessment and sea surface temperature (SST), 500-mbar geopotential height (Z500), 500-mbar specific humidity (SH500), and 500-mbar east-west wind (U500) of the Pacific and the Atlantic Ocean using singular value decomposition (SVD). The spatio-temporal correlation between streamflow and SST was developed first from SVD and thus obtained correlation was later associated with Z500, SH500, and U500 separately to evaluate the …

Spatial Thinking In Astronomy Education Research, Merryn Cole, Cheryl Cohen, Jennifer Wilhelm, Rebecca Lindell

Teaching and Learning Faculty Research

Multiple studies show that spatial thinking skills contribute to students’ performance in science, technology, engineering, and mathematics disciplines. The study of astronomy is no different with the understanding of many astronomical phenomena requiring spatial thinking skills. This paper describes traditional and contemporary approaches to characterizing and measuring spatial thinking skills and suggests how they inform research in astronomy education. It summarizes previous literature in astronomy education research and categorizes the research approaches of astronomy education peer-reviewed journal articles and conference proceedings that explicitly consider the role of spatial thinking. Additionally, it recommends directions and curricular approaches for astronomy education research …

How Middle Level Science Teachers Visualize And Translate Motion, Scale, And Geometric Space Of The Earth-Moon-Sun System With Their Students, Jennifer Wilhelm, Merryn Cole, Cheryl Cohen, Rebecca Lindell

Teaching and Learning Faculty Research

We examined teachers’ spatial-scientific reasoning and the alternative conceptions they held regarding Earth-space content. While participating in a professional development (PD) workshop, teachers engaged in an integrated mathematics and science project-based unit designed to foster spatial reasoning and improve lunar-related conceptual understanding. The Purdue Spatial Visualization Test-Rotation (PSVT-Rot) and the Lunar Phases Concept Inventory (LPCI) were used to assess understanding. We found the teachers held similar alternative conceptions as their students. Moreover, we discovered that teachers had limited understanding of the Earth-Moon-Sun scale, motions, and geometric configurations. To determine how teachers’ spatial-scientific confidence and ability translated to their classroom practice, …

Shergottite Northwest Africa 6963: A Pyroxene‐Cumulate Martian Gabbro, Justin Filiberto, Juliane Gross, Arya Udry, Jarek Trela, Axel Wittmann, Kevin M. Cannon, Sarah Penniston-Dorland, Richard Ash, Victoria E. Hamilton, Andrea L. Meado, Paul Carpenter, Brad Jolliff, Eric C. Ferré

Geoscience Faculty Research

Northwest Africa (NWA) 6963 was found in Guelmim‐Es‐Semara, Morocco, and based on its bulk chemistry and oxygen isotopes, it was classified as a Martian meteorite. On the basis of a preliminary study of the textures and crystal sizes, it was resubclassified as a gabbroic shergottite because of the similarity with terrestrial and lunar gabbros. However, the previous work was not a quantitative investigation of NWA 6963; to supplement the original resubclassification and enable full comparison between this and other Martian samples; here we investigate the mineralogy, petrology, geochemistry, quantitative textural analyses, and spectral properties of gabbroic shergottite NWA 6963 to …