Engineering Commons^™

The Mathematical Theory Of Deformation Arrest In Large-Strain Dynamic Plasticity, Brendan A. Kullback

Mechanical Engineering ETDs

Ductile structural components subjected to explosive loadings exhibit a large range of behaviors. The response of beams, walls, and blast doors is estimated using two methods. The engineering level approaches are highly simplified and neglect much of the relevant physics while the use of finite element or shock-code simulation is expensive and not suited to rapid problem solving and parameter studies. In this dissertation, a medium fidelity reduced order modeling approach has been derived to capture the most relevant physics governing rupture of ductile bodies dynamically deforming in tension.

Solution of the inertially stretching jet is used to reveal the …

Dna Directed Assembly Of Gold-Tipped Metallic Single-Walled Carbon Nanotubes Into Electrical Devices, Ronald D. Salesky

Nanoscience and Microsystems ETDs

Carbon nanotubes have rightfully been regarded as a wonder material since their discovery by Iijima in 1991 and the subsequent elucidation of their many material properties. Their extreme strength is 10-fold higher than any industrial fiber. Their current density carrying capability is orders of magnitude higher than copper without failure from electromigration. Their high thermal conductivity bests diamond, and their structural versatility leads to either semiconducting or metallic electronic character. These properties all make the integration of carbon nanotubes into functional devices of high value. However, they remain a material of largely unrealized potential due to several challenges that arise …

Aluminum Zinc Oxide (Azo) Optimization Process For Use In Optically Transparent Antennas, Maria Elizabeth Zamudio

Electrical and Computer Engineering ETDs

The importance of having an optimal material for fabricating Optically Transparent Antennas (OTAs) is crucial for designing highly efficient antennas that can be integrated with photovoltaics. Transparent Conductor Oxides (TCOs) are promising for OTA fabrication due to their capability of being simultaneously transparent at optical frequencies and conductive within the radio frequency (RF) range. In this work, a new material was developed and optimized to be used for fabricating an optically transparent antenna on a solar cell. Aluminum and Zinc Oxide were co-sputtered onto Si and onto a polycrystalline photovoltaic cell and then annealed between 350°C and 450°C for 24 …

A Frequency Domain Based Approach To Evaluating Manual Tracking Behavior In Parkinson’S Disease, Gabriel A. Parras

Electrical and Computer Engineering ETDs

Parkinson’s disease (PD) is characterized in part by its neurodegenerative effects, which include bradykinesia, tremor, rigidity, and many other symptoms. While treatments such as Levodopa and deep brain stimulation are available, they both have associated complications. Galvanic vestibular stimulation (GVS) is a non-invasive method used to stimulate the vestibular nerves with electric current and it has shown promise as a possible treatment for patients with PD. In order to assess the efficacy of GVS, I examined data collected from a manual pursuit tracking experiment. The experiment involved ten patients with varying severities of PD who were asked to perform a …

Activity Of Pgm-Free Electrocatalysts For Oxygen Reduction Reaction: Ph And Co-Catalysis Effects, Mario Santiago Rojas Carbonell 8148369

Chemical and Biological Engineering ETDs

Fuel cells offer a source to the current and always increasing demand for electric power. But as any new technology, there are challenges that need to be addressed to render it feasible for the market place. One of this challenges is finding the appropriate materials to catalyze the oxygen reduction reaction (ORR) that occurs in the cathode. Oxygen is used as an oxidant in a significant portion of the fuel cells due to its readily availability and high reduction potential. Now, one the bottlenecks that stops the large-scale adoption is the expensive and rare metals that have been used as …

High-Throughput Tensile Testing Reveals Stochastic Properties In Additively Manufactured Steel, Bradley C. Salzbrenner

Mechanical Engineering ETDs

An adage within the Additive Manufacturing (AM) community is that “complexity is free”. Complicated geometric features that normally drive manufacturing cost and limit design options are not typically problematic in AM. While geometric complexity is usually viewed from the perspective of part design, this advantage of AM also opens up new options in rapid, efficient material property evaluation and qualification. This Thesis demonstrates how 100’s of miniature tensile bars can be produced and tested for comparable cost and in comparable time to a few conventional tensile bars. With this technique, it is possible to evaluate the stochastic nature of mechanical …

Reactor Design And Operation Variables To Improve Mixed Algal Biomass Productivity And Solids Separation: An Examination Of Operation Parameters, Density, And Settleability, Derek Jan Wichhart

Civil Engineering ETDs

Algae have been identified as a source of renewable, clean energy, with much research being devoted to identifying high energy yield algae, energy extraction methods, and reactor design with mono-cultures of algae, but little research has been done on reactor design and operational conditions with mixed cultures of algae to improve productivity and solids separation. The objective of this study was to determine if the settling characteristics of mixed algal cultures can be enriched or improved through manipulation of reactor design characteristics by incorporating cyclic settling or floating phases into operation, timing of light/dark cycles, and/or control of the solids …

Integrated Framework For Wildfire Risk Mitigation Planning At The Wildland/Urban Interface, Elmira Kalhor

Civil Engineering ETDs

Past suppression-based wildfire management practices have increased the frequency and intensity of wildfires. Advocates for the re-introduction of natural wildfire regimes must also prioritize wildfire damage protection, especially for vulnerable communities located near forests. Areas where urban and forest lands interdigitate are called the Wildland Urban Interfaces (WUIs). In the United States, the area of the WUIs is increasing, making more people vulnerable to wildfires. By responding to four research objectives, this dissertation proposed and tested an integrated framework for wildfire risk mitigation decision making at WUIs. Decision makers who could benefit from the results of this dissertation include WUI …

Simulation And Analysis Of A Drilling Fluid Using A Herschel-Bulkley Model, Daniel Powell

Mechanical Engineering ETDs

In the study, a drilling fluid with known properties is analyzed and simulated in the laminar regime through a pipe with dimensions of 1.5m in length and 0.02m in diameter. The purpose of the conducted analysis is to demonstrate the advantages of the Herschel-Bulkley model currently used in the oil and gas industry for analyzing non-Newtonian drilling fluids.

For comparison, the analysis is also performed using more simple models for non-Newtonian fluids such as the Bingham Plastic model and the Power Law model and for a Newtonian fluid (water). In addition to analytical models, computations are conducted using …

A Leaky Integrate-And-Fire Neuron With Adjustable Refractory Period And Spike Frequency Adaptation, Jacob N. Healy

Electrical and Computer Engineering ETDs

As standard CMOS technology approaches its physical limitations there is increased motivation to explore new computing paradigms. One possible path forward is to develop an array of computational architectures which specialize in distinct tasks. Neural computing architectures excel at pattern recognition and processing low-fidelity sensory input, but one of the biggest challenges in the field has been implementing architectures which strike an appropriate balance between biologically-plausible performance and the simplicity needed to make large neural systems practical. This work proposes a new VLSI neural architecture which seeks to provide such a balance.

The design described here builds on an implementation …

Use Of Chemical And Isotopic Identifiers To Characterize Ground Water Contamination Near Two Uranium Mill Sites, Central Nm, Mitchell T. Schatz

Civil Engineering ETDs

Chemical and isotopic signatures were used to discriminate between anthropogenic ground water and naturally occurring constituents. The U-234/U-238 activity ratio (AR) was determined in 34 samples from several aquifers underlying two former uranium mills near Milan, NM. Disposal of uranium ore waste into unlined tailings resulted in ground water contamination in the Lower San Mateo Creek Basin area. Ground water contamination from uranium mills have impacted the local ground water for residents down-gradient from the mills.

Previous studies that used uranium isotopes identified activity ratios of mill-derived uranium were near the secular equilibrium of 1, and those from natural ground …

Cognitive Anti-Jamming Framework With Self-Interference Cancellation On A Wideband Autonomous Cognitive Radio, Stephen J. Machuzak

Electrical and Computer Engineering ETDs

With crowded usage of the wireless spectrum, full-duplex wireless systems are introduced to increase bandwidth efficiency by transmitting and receiving on the same frequency band at the same time. Full-duplex communication is a promising solution for greater wireless communications efficiency but, it requires solving the problem of self-interference. Self- Interference cancellation is the process of canceling a radio’s own transmission signal that interferes with its sensed signal which can block desired outside signals of interest. The focus of this thesis is to design and implement a novel self-interference cancellation method for the Wide-band Autonomous Cognitive Radio (WACR) with anti-jamming abil- …

Study Of Vibration For Detection And Recognition Of Concealed Machinery Within Buildings, Sushil Ghimire

Civil Engineering ETDs

Recently international concern about nuclear proliferation has rapidly increased. Some governmental agencies have an interest in remotely detecting and recognizing concealed machinery within buildings to detect any anomalous activity occurring inside the building.

The vibration studies of the roof and the exhaust structures of an existing utility building, the Ford Utility Center at the University of New Mexico and a simplified laboratory structure representing an industrial building, called the doghouse are presented in this thesis. The vibration studies presented allow the reader to understand to what extent it is possible to identify machines concealed within a building.

To identify machines …

A Study Of Iron-Nitrogen-Carbon Fuel Cell Catalysts: Chemistry – Nanostructure – Performance, Michael J. Workman

Nanoscience and Microsystems ETDs

Fuel cells have the potential to be a pollution-free, low-cost, and energy efficient alternative to the internal combustion engine for transportation and small-scale stationary power applications. The current state of fuel cell technology has already achieved two of these three lofty goals. The remaining barrier to wide-scale deployment is the high cost, which is primarily caused by dependence on large amounts of platinum to catalyze the energy conversion reactions. To overcome this barrier and facilitate the integration of fuel cells into mainstream applications, research into a new class of catalyst materials that do not require platinum is needed.

There has …

Design Of An O-Type Metamaterial Slow Wave Structure For High Power Microwave Generation, Sabahattin C. Yurt

Electrical and Computer Engineering ETDs

The aim of this dissertation is to design a novel metamaterial slow wave structure (MSWS) for high power microwave (HPM) generation which is an efficient and compact new generation O-type device whose output parameters are comparable to, and even better than conventional devices. There is increasing interest in using metamaterials for designing HPM sources because of their so-called unique electromagnetic properties that are not found in nature, such as below cutoff propagation, which is the main property that allows for a compact design, and negative refractive index that allows backward wave propagation and reversed Cerenkov radiation. As such new beam/wave …

Practical Considerations In Determining Timber Pile Depth Using The Sonic Echo Method, Ali F. Jwary

Civil Engineering ETDs

The Federal Highway Administration indicates that about 85,000 bridges in the United States have no original contract documents with information about the type, depth, geometry and material of their foundations (FHWA, 2010). Furthermore, the National Bridge Inventory (NBI) provides information about 86,133 bridges nationwide that are rated as scour critical because of unknown foundation condition. In New Mexico, there are more than 281 bridges with unknown foundations, which are owned by the New Mexico Department of Transportation; 71 of these are timber bridges. These data indicate a serious problem that needs decisive action to assess the unknown bridge foundation characteristics …

Intelligent Roic For Real-Time In-Pixel Image Processing, Mohammad J. Ghasemibenhangi

Electrical and Computer Engineering ETDs

As the resolution of current image sensors is increasing and the readout electronics is getting faster, the amount of data produced by these imagers is becoming excessively large to store, transmit, and analyze. As a result, sparse data representation has become an interesting research topic in the last few years. Human eye contains millions of photoreceptors, however, only some sparse data is transmitted to the optic nerves. Image processing techniques implemented on a chip and at the pixel level is the main building blocks for retina-like sensors. In this way, instead of transmitting raw images that require massive storage, and …

Remote Handled Disposal Enhancement At The Waste Isolation Pilot Plant, Philip Theisen

Nuclear Engineering ETDs

The Waste Isolation Pilot Plant (WIPP) is a deep underground facility for the disposal of Transuranic Defense Waste located in Southeastern New Mexico. Transuranic (TRU) Waste is defined as any radionuclides with an atomic number greater than that of Uranium, has a half-life greater than 20 years, and activity greater than 100nanocuries. According to the ‘Land Withdrawal Act’ (LWA), WIPP is licensed to dispose of 6.2million cubic feet of waste. TRU waste is categorized into two types: Contact Handled (CH) and Remote Handled (RH). CH waste is any waste that does not have a surface dose rate that exceeds 200mrem …

Synchronous Generation And Coherent Control Of Extreme Wavelength Radiation And Ultrafast Spectroscopy, Aram Gragossian

Optical Science and Engineering ETDs

Recent progress in ultrafast laser science has made it possible to synthesize and control complex electromagnetic waveforms down to sub-femtosecond timescales. These tailored ultrashort laser pulses can generate coherent bursts of electromagnetic radiation in the extreme ultraviolet (XUV) and terahertz spectral regions with durations reaching the attosecond regime in the XUV region. This is accomplished by coherently controlling electronic motion in gas plasma targets. With these novel radiation sources, ultrafast time-resolved spectroscopy can be performed on a large variety of materials. Knowledge of the spectral phase of an ultrashort pulse is crucial for many applications. There are a variety of …