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Strength, Fracture Evolution, And Permeability Changes From Confined Brazilian Tests On Sandstone, Tyler Louis Hagengruber

Civil Engineering ETDs

This research reports on confined Brazilian strength tests and concurrent permeability testing on sandstone. The majority of the tests measured permeability during loading to failure in the confined extension region. Additional testing includes unloading and reloading cycles to detect the development of microcracks and the dependence of permeability on mixed stress conditions. Further testing characterizes fracture networks by observing porosity changes due to microcrack interactions before peak load. All tests involve 5 cm diameter disk-shaped, jacketed samples that are subjected to confining stresses while they are diametrically loaded. Specially designed end caps allow for gas flow measurements. The test configuration …

Laser Beam Propagation Over Long Distances In Turbulent Media, Justyna O. Sotiris

Mathematics & Statistics ETDs

The propagation of lasers through different media is a broad topic of study and falls under the larger topic of wave propagation. The focus of this thesis is the development and analysis of a numerical computational model of laser beam propagation through a turbulent atmosphere over a long distance. When a beam propagates through a turbulent atmosphere over a distance exceeding several kilometers it is a strong fluctuation propagation. There exist fewer robust methods to demonstrate how strong fluctuations affect the beam. Beam propagation can be described by the Linear Schr\"{o}dinger Equation (LSE). The fluctuations in the refractive index are …

2020-05-01 A Message From Chancellor Roth, Paul B. Roth

HSC Messages from the Chancellor

No abstract provided.

2020-04-20 A Message From Chancellor Roth, Paul B. Roth

HSC Messages from the Chancellor

No abstract provided.

Detection And Classification Of Vibrating Objects In Sar Images, Francisco German Perez Venegas

Electrical and Computer Engineering ETDs

The vibratory response of buildings and machines contains key information that can be exploited to infer their operating conditions and to diagnose failures. Furthermore, since vibration signatures observed from the exterior surfaces of structures are intrinsically linked to the type of machinery operating inside of them, the ability to monitor vibrations remotely can enable the detection and identification of the machinery.

This dissertation focuses on developing novel techniques for the detection and M-ary classification of vibrating objects in SAR images. The work performed in this dissertation is conducted around three central claims. First, the non-linear transformation that the micro-Doppler return …

Modeling And Simulation Of Damage In The Brazilian Indirect Tension Test Using The Finite-Discrete Element Method, Jeremiah C. Leyba

Civil Engineering ETDs

The Brazilian indirect tension test is used to investigate possible correlations between progressive damage and associated permeability changes. The test offers ease of replicability with a damage behavior known to lead to fracture openings as a tool for interpreting the indirect tensile strength of concrete and rocks. This behavior can lend insight into the nature of tensile damage and fracture progression in association with changes in permeability. The nature of these brittle materials is known to exhibit rapid failures in the Brazilian indirect tension test and require a method to retard the progression of damage for the possibility of acquiring …

Characterization And Modeling Of Asphalt Concrete For Dynamic Properties And Performances, A S M A. Rahman

Civil Engineering ETDs

The recently developed mechanistic-empirical pavement design guide (MEPDG, also known as Pavement M-E design method) uses the nationally calibrated, binder viscosity-based dynamic modulus predictive model for the design and analysis of asphalt pavements. In this study, this model is assessed for its appropriateness for asphalt-aggregate mixtures typically used in New Mexico. In essence, this study investigates the predictability issue of complex modulus of New Mexico mixes. A total of 54 Superpave mixes with different aggregate gradations, air voids, and binder grades were collected from the mixing plants and from the pavement construction sites. The loose asphalt mixtures were then compacted, …

Dengue Vaccination Modulates The Dengue-Zika Viral System Via Immunogenic Cross-Talk, Noah J. B. Silva

Biology ETDs

A vaccine for dengue, a viral disease which is a major driver of morbidity and mortality in tropical and subtropical regions, has recently been approved by eleven countries. While vaccination has the potential to reduce disease burden, the approved vaccine faces challenges due to the interactions between the four serotypes of dengue virus (DENV1-4) and the potential interactions with Zika virus (ZIKV), a related flavivirus. In this study, we propose a mathematical model incorporating both DENV and ZIKV in order to investigate the effects of viral competition on dengue vaccine performance, the potential for change in incidence of Zika due …

Characterizing The Viscoelastic Behavior Of Pdms/Pdps Copolymers, Mark E. Small

Mechanical Engineering ETDs

Viscoelasticity is the property of materials that exhibits both viscous and elastic characteristics when undergoing deformation. In polymeric materials, the mechani- cal behavior is dominated by this viscoelastic phenomenon. Creating computational models for these materials can be quite complicated due to their frequency depen- dent and temperature dependent material properties. The research presented in this paper will use state of the art methods to fully develop a material model for a filled polydimethylsiloxane-polydiphenynlsiloxane (PDMS/PDPS) copolymer foam that has yet to be characterized. Mechanical properties of PDMS/PDPS copoly- mers are currently being studied to assess engineering performance, and to provide accurate …

Optimized Sizing And Placing Of Distributed Energy Resources (Ders) In An Island Microgrid Using Der-Cam, Bhuwan B. Bastola

Electrical and Computer Engineering ETDs

The electric grid at La Gomera, an island in the Canary archipelago, has been the subject of interest in optimized integration of Distributed Energy Resources (DERs) primarily because of high distribution losses and concerns about complying with emission regulations. Consequently, the utility that operates the island power system wishes to mitigate the problem with installation of renewable and distributed energy sources like PV and battery, which is the focus of this research.

Specifically, the focus of this thesis is to use Distributed Energy Resource - Customer Adoption Model (DER-CAM) to optimize the installation of PV and battery in terms of …

Scheduling Heterogeneous Hpc Applications In Next-Generation Exascale Systems, Oscar Hernan Mondragon Martinez

Computer Science ETDs

Next generation HPC applications will increasingly time-share system resources with emerging workloads such as in-situ analytics, resilience tasks, runtime adaptation services and power management activities. HPC systems must carefully schedule these co-located codes in order to reduce their impact on application performance. Among the techniques traditionally used to mitigate the performance effects of time- share systems is gang scheduling. This approach, however, leverages global synchronization and time agreement mechanisms that will become hard to support as systems increase in size. Alternative performance interference mitigation approaches must be explored for future HPC systems. This dissertation evaluates the impacts of workload concurrency …

Using Rollback Avoidance To Mitigate Failures In Next-Generation Extreme-Scale Systems, Scott Levy

Computer Science ETDs

High-performance computing (HPC) systems enable scientists to numerically model complex phenomena in many important physical systems. The next major milestone in the development of HPC systems is the construction of the first supercomputer capable executing more than an exaflop, 10^18 floating point operations per second. On systems of this scale, failures will occur much more frequently than on current systems. As a result, resilience is a key obstacle to building next-generation extreme-scale systems. Coordinated checkpointing is currently the most widely-used mechanism for handling failures on HPC systems. Although coordinated checkpointing remains effective on current systems, increasing the scale of today's …

Modeling The Influence Of The Heterogeneous Substrate On The Transport Of The Jet Fuel Solute Plume, Kirtland Air Force Base, Albuquerque, New Mexico, Hannah Sarah Gatz-Miller

Earth and Planetary Sciences ETDs

A subsurface model was developed to characterize the influence of heterogeneity on solute phase plume migration of the Jet Fuel spill of Kirtland Air Force Base. Core –logs from KAFB boreholes were compiled, and lithology was interpolated across the study area using transition probability geostatistics (T-PROGS). High conductivity materials in the travel path resulted in a faster than average breakthrough time while, if low conductivity materials were placed in the travel path, particles were either forced to divert around the low K material, which added time and changed the direction of travel, or were forced by the hydraulic gradient to …

Predicting Activation Of Experiments Inside The Annular Core Research Reactor, Joseph Greenberg

Nuclear Engineering ETDs

The objective of this thesis is to create a program to quickly estimate the radioactivity and decay of experiments conducted inside of the Annular Core Research Reactor (ACRR) at Sandia National Laboratories and eliminate the need for users to write code. This estimation is achieved by using MCNP to model the neutron fluxes in the reactors central cavity where experiments are conducted using one of the four possible neutron spectra available in the ACRR. The desired neutron spectrum, experiment material composition, and reactor power level are then input into CINDER2008 burnup code to obtain activation and decay information for every …

Analysis With Smart Grid Methods & Solutions, Brian Arellano

Electrical and Computer Engineering ETDs

Smart Grid Technologies such as demand Response, energy storage, microgrids, advanced communication technologies, and are being rapidly adopted into the electric grid by the each technology. Utilities making efforts to support, invest, adopt and implement these. One challenge is not necessarily adopting the technology, but first identifying the impact of the technology and comparing with its benefits. Another challenge, and the most important one, is how would all these technologies work together on the electric grid. One benefit of a technology might be counterproductive to a benefit from another technology. This challenge of understanding multiple technologies is important because when …

On Dynamic Modulus Of Asphalt Concrete For Moisture Damage, Mekdim Weldegiorgis

Civil Engineering ETDs

Dynamic modulus (E*) test has gained substantial acceptance in recent years for evaluating Hot Mix Asphalt (HMA) rutting and fatigue cracking performances. Indeed, the recently developed Mechanistic Empirical Pavement Design Guide (MEPDG) uses E* data for stress and strain calculation, and E*-based models for prediction fatigue and rutting performances of a HMA pavement. Unfortunately, neither HMA mix design method nor the MEPDG uses E* value to evaluate moisture damage characteristics of HMA pavements. In fact, moisture damage is a very complex problem, and there exists no models for inclusion in the MEPDG for predicting moisture damage performance of HMA pavements. …

Modeling Moisture-Induced Damage In Asphalt Concrete, Mohammad Hossain

Civil Engineering ETDs

Moisture damage in Asphalt Concrete (AC) is not new but an unsolved problem. For decades laboratory studies have been conducted on both loose and compacted mix to understand the effects of moisture on the AC damage. Adhesive and cohesive damages are the two major types of damages occur inside the AC. Adhesive damage is a separation between aggregate and coated mastic or matrix materials and cohesive damage is the degradation of strength of matrix materials within the AC samples. In this study, Finite Element Method (FEM) modeling technique is used to identify initiation and progression of adhesive and cohesive damage. …

Quantitative Structure-Property Relationships For Predicting Chlorine Demand And Disinfection Byproducts Formation In Drinking Water, Gebhard Luilo

Chemistry and Chemical Biology ETDs

Models are important tools for designing or redesigning water treatment processes and technologies to minimize disinfection byproducts (DBPs) formation without compromising disinfection efficiency. Empirical models, which are the most common, are based on bulk water quality parameters that vary with time and space. These parameters may not always have linear relationships with chlorine demand and DBPs formation which make structure-based models more attractive to study. In this dissertation, Quantitative Structure-Property Relationship (QSPR) models which make use of structural properties of individual molecules were developed using experimental data obtained from the literature. The amounts are reported in moles of chlorine (HOCl) …

The Spatial Ecology Of Galapagos Tortoises And New Mexico's Reptiles, Jacek Tomasz Giermakowski

Biology ETDs

The analysis of spatial processes and spatial heterogeneity is an important part of ecology because distribution of organisms in space partly defines ecology as a discipline. In addition, advances in analysis of DNA, geographical computing and the availability of vast amounts of environmental data obtained by satellites provide new opportunities for studying ecology at different spatial and phylogenetic scales. My research takes advantage of information gathered by satellites and adds modeling and data collected on the distribution of different reptiles to examine processes at various spatial and temporal scales. In Chapter 1 I describe how juvenile Galapagos tortoises change their …

Biogeography Of Alien Vertebrates In The Galapagos Islands : Patterns, Processes, And Conservation Implications, Reese Brand Phillips

Biology ETDs

Alien species are one of the principal threats to global biodiversity. Insular ecosystems have proven exceptionally susceptible to invasion by aliens and vulnerable to their negative effects. Some of the most destructive alien species are vertebrates, in part due to their having been introduced to islands worldwide. Rodents (Rattus spp. and Mus musculus) are among the most widespread and devastating invasive species for insular flora and fauna. In this research I investigate the biogeographic patterns and processes of alien vertebrates in the Galapagos Islands, focusing on the mechanisms that influence their dispersal and colonization within the archipelago. In the first …