Physical Sciences and Mathematics Commons^™

Photoproduction Of Λ And Σº Hyperons Using Linearly Polarized Photons, C. A. Paterson, D. G. Ireland, K. Livingston, B. Mckinnon, D. Adikaram, M. Amaryan, Y. Prok, B. Torayev

Physics Faculty Publications

Background: Measurements of polarization observables for the reactions ^→ᵧp→K+ Λ and ^→ᵧp→ K+Σ⁰ have been performed. This is part of a program of measurements designed to study the spectrum of baryon resonances in particular, and nonperturbative QCD in general.

Purpose: The accurate measurement of several polarization observables provides tight constraints for phenomenological fits, which allow the study of strangeness in nucleon and nuclear systems. Beam-recoil observables for the ^→ᵧp→ K+Σ⁰ reaction have not been reported before now.

Method: Themeasurements were carried out using linearly polarized photon beams incident on a liquid hydrogen target, and the …

Trade-Offs Between Three Forest Ecosystem Services Across The State Of New Hampshire, Usa: Timber, Carbon, And Albedo, David A. Lutz, Elizabeth A. Burakowski, Mackenzie B. Murphy, Mark E. Borsuk

Dartmouth Scholarship

Forests are more frequently being managed to store and sequester carbon for the purposes of climate change mitigation. Generally, this practice involves long-term conservation of intact mature forests and/or reductions in the frequency and intensity of timber harvests. However, incorporating the influence of forest surface albedo often suggests that long rotation lengths may not always be optimal in mitigating climate change in forests characterized by frequent snowfall. To address this, we investigated trade-offs between three ecosystem services: carbon storage, albedo-related radiative forcing, and timber provisioning. We calculated optimal rotation length at 498 diverse Forest Inventory and Analysis forest sites in …

The Pathology Of Command And Control: A Formal Synthesis, Michael Cox

Dartmouth Scholarship

One of the most important theories in the study of environmental governance and policy is the pathology of command and control, which describes the negative consequences of top-down, technocratic governance of social and ecological systems. However, to date, this theory has been expressed somewhat inconsistently and informally in the literature, even by the seminal works that have established its importance and popularized it. This presents a problem for the sustainability science community if it cannot be sure of the precise details of one of its most important theories. Without such precision, applications and tests of various elements of the theory …

Anatomy, Implant Selection And Placement Influence Spine Mechanics Associated With Total Disc Replacement, Justin F.M. Hollenbeck

Electronic Theses and Dissertations

Through aging and injury, the intervertebral disc of the lumbar spine can undergo degeneration, leading to collapse of the vertebrae and low back pain, a symptom that affects half the adult population in any given year. In an effort to reduce low back pain, total disc replacement treatment removes the degenerated disc, restores natural height and lordosis of the segment, and preserves motion at the joint. Patient anatomy, implant selection, and implant placement play significant roles in a patient's outcomes after total disc replacement surgery. Thus, the objective of the work presented in this thesis was to develop a suite …

Sawtooth Profile In Smectic A Liquid Crystals, Carlos J. Garcia-Cervera, Tiziana Giorgi, Sookyung Joo

Mathematics & Statistics Faculty Publications

We study the de Gennes free energy for smectic A liquid crystals over S^2-valued vector fields to understand the chevron (zigzag) pattern formed in the presence of an applied magnetic field. We identify a small dimensionless parameter a, and investigate the behaviors of the minimizers when the field strength is of order O (ε^-1). In this regime, we show via Γ-convergence that a chevron structure where the director connects two minimum states of the sphere is favored. We also analyze the Chen-Lubensky free energy, which includes the second order gradient of the smectic order parameter, and …

The Martian Surface Radiation Environment- A Comparison Of Models And Msl/Rad Measurements, Daniel Matthiä, Bent Ehresmann, Henning Lohf, Jan Köhler, Cary Zeitlin, Jan Appel, John W. Wilson

Mathematics & Statistics Faculty Publications

Context: The Radiation Assessment Detector (RAD) on the Mars Science Laboratory (MSL) has been measuring the radiation environment on the surface of Mars since August 6th 2012. MSL-RAD is the first instrument to provide detailed information about charged and neutral particle spectra and dose rates on the Martian surface, and one of the primary objectives of the RAD investigation is to help improve and validate current radiation transport models.

Aims: Applying different numerical transport models with boundary conditions derived from the MSL-RAD environment the goal of this work was to both provide predictions for the particle spectra and the radiation …

Evaluation Of Ray-Path Integrals In Geometrical Optics, John A. Adam, Michael Pohrivchak

Mathematics & Statistics Faculty Publications

A brief summary of the physical context to this paper is provided, and the deviation angle undergone by an incident ray after k internal reflections inside a transparent unit sphere is formulated. For radially inhomogeneous spheres (in particular) this angle is related to a ray-path integral; an improper integral for which there are relatively few known exact analytical forms, even for simple refractive index profiles n(r). Thus for a linear profile the integral is a combination of incomplete elliptic integrals of the first and third kinds (though not all are as complicated as this). The ray-path integral is evaluated …

Design And Evaluation Of The Impact Of A Multi-Agent Control System (Framework) Applied To A Social Setting, Perez Antonio Perez

Open Access Theses & Dissertations

The objective of this research is to design and analyze the performance of a new mechanism to improve the advising of students in a nontraditional environment. This nontraditional environment includes: a minority serving, commuter campus with a high percentage of transfer students. Specifically, these demographics are unable to keep a tightly controlled cohort of students flowing through to the completion of the curriculum. Students in these circumstances usually have varied course loads and competing priorities due to family and financial needs or other societal responsibilities. Therefore, there is a need for an individualized approach to advising.

University administrations face challenges …

Geology, Geochemistry, And 3d Geological Modelling Of The Independencia - Los Bancos Ag-Au Epithermal Vein Systems In The Palmarejo District, Chihuahua, Mexico, Arturo Ramirez

Open Access Theses & Dissertations

The Sierra Madre Occidental (SMO) is a Cretaceous-Tertiary silicic ignimbrite province in northwestern Mexico. It is the result of tectonic and magmatic events produced by the subduction of the Farallon plate under North America (80-40 Ma) and the opening of the Gulf of California (14-12 Ma), thus forming the SMO metallogenic provinces. The Late Eocene to Oligocene was a major period of metallic mineralization hosting various deposit types, principally Ag-Au (±Pb-Zn-Cu) epithermal veins, which have been economically significant.

The study area lies in the Palmarejo district, operated by Coeur Mining Inc., which was the worldâ??s fifth largest silver producer in …

National Evaluation For Development And Exploration Potential Of Mineral Commodities In Produced Waters, Stephanie Ray

Open Access Theses & Dissertations

The U.S. Geological Survey recently updated a geochemical database consisting of data for approximately 160,000 produced waters samples, primarily from petroleum and geothermal reservoirs. Using major and trace elements from conventional and unconventional well types from the database, this Thesis provides a comprehensive, national evaluation for mineral commodity potential in produced waters. Produced waters contain virtually every naturally occurring element and can range in salinity to several times that of seawater. Despite the typical outlook to view produced waters as a waste, they have potential for natural resource development.

This Thesis provides, for each mineral commodity found in the produced …

Development Of Efficient Simultaneous Confidence Bounds For Linear Mixed Models With Applications In Alcohol Research, Emmanuel Joseph Sequeira

Open Access Theses & Dissertations

Multiplicity corrections are necessary to ensure the accuracy of conclusions made in studies that carry out multiple inferences simultaneously. This Thesis uses the methodology derived by Hunter and Worsley to obtain improved simultaneous confidence bounds (SCBs) that are less conservative than the highly used Bonferroni SCBs, for studies using linear mixed modeling. Empirical coverage rates were obtained for data that was generated using simulations, to compare the accuracy of the Hunter-Worsley SCBs with that of the Bonferroni SCBs. The bounds were also applied to data in the field of alcohol research, where comparisons were made to determine the moderating effect …

Investigation Of Lunar Subsurface Cavities Using Thermal Inertia And Temperature Maximum To Minimum Ratios, Rachel Ann Slank

Open Access Theses & Dissertations

Previous studies have revealed a small number of subsurface cavities, including lava tubes, as well as skylights, lava flow pits, and impact melt pits on the Moon. The interiors of subsurface cavities would have been protected from micrometeorite bombardment, solar radiation, space weathering, and extreme diurnal temperature swings over long periods of geologic time. As a result, subsurface cavities can provide access to pristine crustal samples and stratigraphy. These cavities may also harbor important volatiles, such as water ice, that would enable future exploration missions by relieving many operational constraints, including the supply of propellants and life support. In addition, …

Computational Modeling Of A 60kw Oxy-Methane Direct Power Extraction Combustor, Omar Daniel Vidana

Open Access Theses & Dissertations

ANSYS Fluent was used to optimize components of a direct power extraction combustor. This includes the fuel injector, nozzle, and cooling units. Changes in the injector's inlet location impacted pressure and velocity distribution. An angle of 115 degrees with respect to the x-axis was found to increase distribution efficiency. Temperature and velocity data from the combustor and nozzle were calculated using NASA CEA and Fluent. Magnitudes of temperature and velocity for CEA and Fluent matched within 9% and 4%, respectively. For the cooling system it is expected that cavitation will not occur since the saturation temperature of water is not …

Climate Change: Causes, Effects, And Solutions, Jameel R. Kaddo

A with Honors Projects

Climate change has become a widespread topic in recent years. This a problem that resulted from the emission of greenhouse gases that affect our environment. Therefore, it raises questions on whether the problem is caused by human activities or it’s just a part of nature’s cycle. This paper discusses and compares the factors that contribute to climate change by humans and nature, some effects of climate change, and some solutions that have been developed to prevent or slow climate change from progressing.

Careers With Chemistry, Ebru Taskan

A with Honors Projects

For this poster assignment, the student provides data on EDTA, it's chemical formula, composition, uses, and health effects, as well as featuring a career that uses chemistry, in this case nurse practitioner.

An Application Of The Spectral Theorem To The Laplacian On A Riemannian Manifold, Paul Bracken

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

There continues to be great interest in the study of the heat equation on Riemannian manifolds. This may be due to the remarkable more recent work of Patodi [1]. It may also be due in part to the asymptotic expansion of Minakshisundaram and Pleijel. The heat equation involves a parabolic partial differential equation that describes the distribution of heat in a given region over time. This equation has also appears in probability theory to describe random walks. The heat equation is also of importance in Riemannian geometry, topology and applied mathematics.

Stability Analysis And Hopf Bifurcation Of Density-Dependent Predator-Prey Systems With Beddington-Deangelis Functional Response, Xin Jiang, Zhikun She, Zhaosheng Feng

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

In this article, we study a density-dependent predator-prey system with the Beddington-DeAngelis functional response for stability and Hopf bifurcation under certain parametric conditions. We start with the condition of the existence of the unique positive equilibrium, and provide two sufficient conditions for its local stability by the Lyapunov function method and the Routh-Hurwitz criterion, respectively. Then, we establish sufficient conditions for the global stability of the positive equilibrium by proving the non-existence of closed orbits in the first quadrant R²+. Afterwards, we analyze the Hopf bifurcation geometrically by exploring the monotonic property of the trace of the Jacobean matrix with …

Metabolic Health Has Greater Impact On Diabetes Than Simple Overweight/Obesity In Mexican Americans, Shenghui Wu, Susan P. Fisher-Hoch, Belinda M. Reininger, Kristina Vatcheva, Joseph B. Mccormick

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

To compare the risk for diabetes in each of 4 categories of metabolic health and BMI. Methods. Participants were drawn from the Cameron County Hispanic Cohort, a randomly selected Mexican American cohort in Texas on the US-Mexico border. Subjects were divided into 4 phenotypes according to metabolic health and BMI: metabolically healthy normal weight, metabolically healthy overweight/obese, metabolically unhealthy normal weight, and metabolically unhealthy overweight/obese. Metabolic health was defined as having less than 2 metabolic abnormalities. Overweight/obese status was assessed by BMI higher than 25 kg/m2. Diabetes was defined by the 2010 ADA definition or by being on a diabetic …

A Polyhedral Model Of Partitions With Bounded Differences And A Bijective Proof Of A Theorem Of Andrews, Beck, And Robbins, Felix Breuer, Brandt Kronholm

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

The smallest part is a rational function. This result is similar to the closely related case of partitions with fixed differences between largest and smallest parts which has recently been studied through analytic methods by Andrews, Beck, and Robbins. Our approach is geometric: We model partitions with bounded differences as lattice points in an infinite union of polyhedral cones. Surprisingly, this infinite union tiles a single simplicial cone. This construction then leads to a bijection that can be interpreted on a purely combinatorial level.

The Neural Dynamics Of Somatosensory Processing And Adaptation Across Childhood: A High-Density Electrical Mapping Study, Neha Uppal, John J. Foxe, John Butler, Frantzy Acluche, Sophie Molholm

Articles

Young children are often hyperreactive to somatosensory inputs hardly noticed by adults, as exemplified by irritation to seams or labels in clothing. The neurodevelopmental mechanisms underlying changes in sensory reactivity are not well understood. Based on the idea that neurodevelopmental changes in somatosensory processing and/or changes in sensory adaptation might underlie developmental differences in somatosensory reactivity, high-density electroencephalography was used to examine how the nervous system responds and adapts to repeated vibrotactile stimulation over childhood. Participants aged 6–18 yr old were presented with 50-ms vibrotactile stimuli to the right wrist over the median nerve at 5 blocked interstimulus intervals (ranging …

Mathematics Learning Support Across A Multi-Campus Institution: A Prototype Of Virtual Support, Cormac Breen, Ciaran O'Sullivan, Damian Cox

Articles

In this paper, a study on Mathematics Learning Support (MLS) that was undertaken across three institutes intending to form the Technological University for Dublin is outlined. This study consisted of a survey that was circulated to both staff and students in each of the three institutes. The survey had two objectives. Firstly it sought to identify the students’ needs for MLS in each of the three institutes. Secondly, it sought to ascertain the preferred method of provision of MLS, on a scale ranging from exclusively online, to exclusively in person. Following on the results of this survey it was decided …

Adapting Near-Ultraviolet Colorimetry For Long-Term In Situ Monitoring Of Hexavalent Chromium In Groundwater Aquifers, Janine Carter

Graduate Student Theses, Dissertations, & Professional Papers

This paper briefly describes sources of hexavalent chromium [Cr(VI)] and the risk it poses to human health and the environment; current methods used to regulate, monitor, and measure Cr(VI); the basic design of a submersible, direct-reading sensor in development for long-term monitoring of Cr(VI) concentration in natural waters; and the means developed to correct sensor readings for two common analytical interferences, turbidity and pH, that could lead to an incorrect measurement of Cr(VI). The principal purposes of this study are to analyze the current methods used to compensate for sample turbidity, to develop methods to compensate for sample pH, and …

Adaptation On A Budget: How Vietnamese Innovators Are Trying To Design Their Way Out Of Climate Change, Shanti R. Johnson

Graduate Student Theses, Dissertations, & Professional Papers

In the rapidly developing Mekong Delta of Vietnam, young innovators are facing a challenge far greater than simply trying to catch up with the wealthier world. In a growing trend, the next generation of Vietnamese is acting under a common understanding: climate change is real, it’s here and the time to respond is growing short.

For over a decade, Southern Vietnam has consistently been ranked by international organizations like the Intergovernmental Panel on Climate Change as one of the most vulnerable places in the world to the impacts of climate change. That vulnerability is heightened by the fact that the …

Chillisource Game Engine Particle System Study, Angela Gross

Graduate Student Theses, Dissertations, & Professional Papers

The majority of modern game engines utilize intricate objects called particle systems which are a collection of many particles that together represent an object without well-defined surfaces. This thesis discusses the results of studying and stressing particle systems within ChilliSource, an open-source game engine written in C++, with the goal of understanding a complex system and exploring possible optimizations that could be made to it. The studies performed were driven by metrics generated with custom profiling classes that kept track of things like the number of particles rendered, how long the engine spent rendering particles, or even how long a …

73,401 Hexagons: A Geodiversity Gap Analysis Of The Crown Of The Continent Ecosystem, Robina A. Moyer

Graduate Student Theses, Dissertations, & Professional Papers

The Crown of the Continent Initiative (CCI) is a transboundary collaborative of conservation groups who work to further conservation goals throughout the Crown of the Continent Ecosystem, located in Northwestern Montana and southern British Columbia and Alberta. CCI and their member groups are interested in using geodiversity as a conservation measure in the Crown Ecosystem. First suggested in 1988 (Hunter et al.), geodiversity, or land facets, are typically a combination of abiotic features used as surrogates for the overlying biotic features. Conservation planning often employs an approach of coarse and fine filters, gap analysis, and systematic reserve design to identify …

On Monomial Resolutions Supported On Posets, Daniel Wood

Legacy Theses & Dissertations (2009 - 2024)

In this thesis we establish two independent ideas. Firstly, given a monomial ideal I with

Structured Summarization Of Multi-Party Conversations, Ching-Sheng Lin

Legacy Theses & Dissertations (2009 - 2024)

Automatic summarization is the task of creating a set of short and concise sentences that capture the content of the original source material. Summaries should retain only the most relevant content of the source, while suppressing secondary and redundant information. Most existing approaches to automatic summarization have been applied to narrative documents such as news, reports, and technical documents. Relatively few techniques were proposed for summarizing meetings and other forms of interactive content.

Uv Light-Induced Aggregation Of Titania Submicron Particles, Can Zhou, Yashar Bashirzadeh, Timothy A. Bernadowsky Jr., Xiaoyu Zhang

Mechanical & Aerospace Engineering Faculty Publications

In this study, aggregation of TiO₂ (rutile and anatase) submicron particles in deionized (DI) water under ultra-violet (UV) light irradiation was investigated. While no aggregation was observed in the dark, rutile and anatase submicron particles started aggregating upon application of UV light and ceased aggregation in about 2 and 8.4 h, respectively. It has been demonstrated that UV light directly mitigated the particle mobility of TiO₂, resulting in a neutralization effect of the Zeta potential. It was also observed that rutile particles aggregated much faster than anatase particles under UV radiation, indicating that the Zeta potential of …

An Efficient Solution To The Mixed Shop Scheduling Problem Using A Modified Genetic Algorithm, V. Nguyen, H. P. Bao

Mechanical & Aerospace Engineering Faculty Publications

The mixed job shop scheduling problem is one in which some jobs have fixed machine orders and other jobs may be processed in arbitrary orders. In past literature, optimal solutions have been proposed based on adaptations of classical solutions such as by Johnson, Thompson and Giffler among many others, by pseudopolynomial algorithms, by simulation, and by Genetic Algorithms (GA). GA based solutions have been proposed for flexible Job shops. This paper proposes a GA algorithm for the mixed job shop scheduling problem. The paper starts with an analysis of the characteristics of the so-called mixed shop problem. Based on those …

Margaret Chase Smith Essay: Maine And Climate Change: The View From Greenland, Angus King

Maine Policy Review

Senator King discusses the issue of climate change and what it may mean for Maine and the nation in light of trip he took to Greenland in August 2016.