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Articles 1 - 15 of 15
Full-Text Articles in Engineering
Early-Age Strength And Failure Characteristics Of 3d Printable Polymer Concrete: Numerical Modelling And Experimental Testing, Mohammad Amin Dehghani Najvani
Early-Age Strength And Failure Characteristics Of 3d Printable Polymer Concrete: Numerical Modelling And Experimental Testing, Mohammad Amin Dehghani Najvani
Civil Engineering ETDs
The time-dependent rheological and early-age strength parameters of Polymer concrete (PC) were investigated. PC flow decreased, and the static yield stress and thixotropy increased as the specimen aged, while the dynamic yield stress remained unchanged. The study found that the Herschel-Bulkley model can accurately describe the PC’s rheological behavior over time. The change in cohesion strength and internal friction angle over time was observed using uniaxial unconfined compression and direct shear tests of fresh PC. A time-dependent MohrCoulomb failure criterion was established. Temperature analysis was used to determine the gel time and explain the evolution of the time-dependent early-age strength …
Modeling Of Asphalt Concrete For Cross-Anisotropic Visco-Elasticity And Heterogeneity, Zafrul Hakim Khan
Modeling Of Asphalt Concrete For Cross-Anisotropic Visco-Elasticity And Heterogeneity, Zafrul Hakim Khan
Civil Engineering ETDs
Asphalt Concrete (AC) is a cross-anisotropic viscoelastic material. This study has developed a methodology to backcalculate the cross-anisotropic properties of the AC layer from the Falling Weight Deflectometer (FWD) sensor and pavement response data from embedded sensors inside a pavement section. This study has also developed a two-way coupled Multiscale Finite Element Model (MsFEM) with Phase Field Fracture (PFF) to study the microstructural heterogeneity and damage of the AC layer based on the actual field loadings. A Finite Difference Time Domain (FDTD) and Machine learning-based backcalculation algorithm were developed to determine the layer thickness and dielectric constant from air-coupled Ground …
Post-Wildfire Export Regimes Of Solutes Along The Gallinas-Pecos River-Santa Rosa Fluvial Network, Asmita Kaphle
Post-Wildfire Export Regimes Of Solutes Along The Gallinas-Pecos River-Santa Rosa Fluvial Network, Asmita Kaphle
Civil Engineering ETDs
Wildfires significantly contribute to water pollution when ash and sediments, including nutrients and metals, are released into fluvial systems, impacting aquatic ecosystems and surrounding communities. This study focuses on the impacts of the Hermits Peak-Calf Canyon Fire on the Gallinas and Pecos watersheds. It employs five monitoring stations along a 190km fluvial network to assess solute export regimes post-fire, where grab samples were collected for nutrient and metal analyses for a period of more than a year. The metrics used for characterizing mobilization, chemostatic, or dilution patterns indicated mobilization for most solutes at all sites upstream of Santa Rosa Lake. …
Performance Evaluation Of E-Ticketing Technologies On Asphalt Paving Projects In New Mexico, Gena C. Robertson
Performance Evaluation Of E-Ticketing Technologies On Asphalt Paving Projects In New Mexico, Gena C. Robertson
Civil Engineering ETDs
The collection and processing of paper tickets for construction material delivery is an inefficient and antiquated practice that exposes inspectors on highway paving projects to substantial safety risks. An alternative to the collection of paper tickets is e-Ticketing, which uses web-based systems to deliver similar information. This research documented a current paper ticketing process and compared it to an e-Ticketing process that was implemented on several pilot projects. Data were obtained using stakeholder meetings, personnel interviews, and surveys. When compared to a paper ticketing system, e-Ticketing was shown to have fewer opportunities for error, require fewer decision points, and provide …
Role Of Endophytic Fungi On Arsenic Uptake In Solution: Insights For Bioremediation, Taylor Lillian Busch
Role Of Endophytic Fungi On Arsenic Uptake In Solution: Insights For Bioremediation, Taylor Lillian Busch
Civil Engineering ETDs
Hazardous metals mobilized from natural deposits and mining legacy are environmental and human health concerns. The waters of our partner Native American communities affected by uranium and gold mining legacy exceed the EPA MCL of 10 µg/L arsenic (As). Bioremediation is a novel technology that uses native resources to remediate metals in the soil and groundwater. Plant-fungi symbiosis for bioremediation is widely studied, but the role of endophytic fungi in metal uptake is not well understood. The objectives of this study are to 1) determine As uptake by symbiotic endophyte Cadophora sp. and little bluestem grass (Schizachyrium scoparium) …
Hydraulic Habitat Suitability For The Rio Grande Silvery Minnow At The Los Chavez Irrigation Outfall, New Mexico, Haley A. Ormsbee
Hydraulic Habitat Suitability For The Rio Grande Silvery Minnow At The Los Chavez Irrigation Outfall, New Mexico, Haley A. Ormsbee
Civil Engineering ETDs
It is essential to manage the Middle Rio Grande for aquatic species to preserve the native biodiversity of the river. During periods of low flow, endangered species such as the Rio Grande Silvery Minnow (RGSM) may get trapped in a drying reach without the ability to escape from isolated pools. Very little is known about how areas of refuge, such as irrigational outfall channels, buffer RGSM from stream flow intermittency. Hence, there is a crucial need to quantify available habitat for RGSM in areas of refuge. This study aims to make connections between flow regimes and physical-habitat conditions to help …
Identifying The Required Ecological Flow For Sediment Movement In The Río Chama: Field Data Informed Visual Spatial Model, Cristian Kremer
Identifying The Required Ecological Flow For Sediment Movement In The Río Chama: Field Data Informed Visual Spatial Model, Cristian Kremer
Civil Engineering ETDs
The continuous alteration of flow regimes in rivers has led to negative impacts on habitats and biotic communities, causing irreversible effects on river biodiversity. Implementing e-flows in management strategies can repair historical mismanagement, prevent further degradation, and restore ecosystem services. In the case of the Rio Chama, damming has altered its hydrological regime, affecting sediment transport. Experts recommend specific e-flow conditions for the Rio Chama to improve ecological conditions, in particular a bankfull discharge of 70 m3s-1 every 2 years for sediment flushing and channel maintenance. The Río Gallina, a tributary of the Rio Chama, plays a …
Repair Of A Wellbore Microannulus, Serafin Garcia Fernandez
Repair Of A Wellbore Microannulus, Serafin Garcia Fernandez
Civil Engineering ETDs
In wellbore systems, the microannulus between the steel and the cement has been shown to be a critical leakage pathway. This microannulus offers unique roughness, aperture distribution, and wetting conditions, which are critical in understanding and explaining the potential sealing efficiency of a repair material. An experimental configuration was developed to better understand how a repair material would displace an existing material in the microannulus, visually evaluate potential instabilities on the flow patterns developed, and how efficient the potential repair would be. For that purpose, the experimental configuration consisted of a planar, rough cement surface and a transparent acrylic plate …
Development Of The Navigator: A Lagrangian Smart Sensing System To Characterize Aquatic Ecosystems., Aashish Sanjay Khandelwal
Development Of The Navigator: A Lagrangian Smart Sensing System To Characterize Aquatic Ecosystems., Aashish Sanjay Khandelwal
Civil Engineering ETDs
Most freshwater aquatic studies rely on Eulerian monitoring, i.e., water quality and quantity are monitored using grab samples or semi-continuous sensors deployed at fixed cross-sections. While Eulerian monitoring is practical, it provides a limited understanding of spatial and temporal heterogeneity and their effects on environmental processes. This dissertation summarizes the design and application of The Navigator, an alternative Lagrangian monitoring system that offers cost-effective solutions for in-situ, real-time data collection in lotic and lentic freshwater ecosystems such as streams, rivers, ponds, and reservoirs. The Navigator features a suite of methods – an autonomous surface vehicle (ASV) with GPS and LTE …
Gold Thin Film Electrodes For High Sensitivity & Selectivity Electrochemical Detection Of Arsenite In Water, Tybur Q. Casuse Driovínto
Gold Thin Film Electrodes For High Sensitivity & Selectivity Electrochemical Detection Of Arsenite In Water, Tybur Q. Casuse Driovínto
Civil Engineering ETDs
This is partial fulfillment of a dissertation defense on electrochemical detection of Arsenic (As) in water using gold (Au) nanofilms as sensing electrodes. The maximum contaminant level of Arsenic in drinking water is set at 10 g L-1 by the WHO and USEPA. Electrochemical detection by linear stripping voltammetry has comparable detection limits to more expensive laboratory-based methods but with added benefits of being portable and manufacturable. The work has developed sputtered and crystallographically oriented nanofilms for detection of trace As (III). Ultraflat Au(111) oriented thin films, Au(UTF), were compared to single crystal model electrodes to identify the impacts …
Strength As A Function Of Liquid Water Content In Different Snow Types - Results From Field Experiments Using A Blade Hardness Gauge, Mikael Schlumpf
Strength As A Function Of Liquid Water Content In Different Snow Types - Results From Field Experiments Using A Blade Hardness Gauge, Mikael Schlumpf
Civil Engineering ETDs
The rapid weakening of snow layers that locally accumulate infiltrating liquid water is a well-known mechanism for wet slab avalanche formation. To quantify this process and improve the prediction of these destructive avalanches, a blade hardness gauge (BHG, a.k.a thin blade penetrometer) and SLF snow sensor were used to take 349 targeted paired measurements of strength and LWC, respectively, in the snow above 19 artificially wetted capillary barriers. Using a multiple regression analysis, we develop an expression for the blade hardness of manually wetted snow as a function of LWC, crystal form, and blade hardness prior to wetting. To understand …
3d Printing Of Earthen Materials: Toward The Carbon-Zero Construction, Shiva Bhusal
3d Printing Of Earthen Materials: Toward The Carbon-Zero Construction, Shiva Bhusal
Civil Engineering ETDs
In recent years, digital manufacturing techniques in the architecture and construction industry have rapidly gained attention, especially with 3D printing, also called additive manufacturing. The use of cement has been common in modern construction and is now being explored for 3D printing. However, due to cement's contribution to approximately 7 percent of global carbon emissions and its high cost, research on sustainable and greener materials has gained attention. Previous studies on alternative construction have examined the mechanical and rheological properties of soil mixes, but not much attention has been given to printability evaluation, shrinkage, and cracking, which can affect the …
Additive Manufacturing Of Lightweight Concrete Mixtures, Kourosh Rashidi
Additive Manufacturing Of Lightweight Concrete Mixtures, Kourosh Rashidi
Civil Engineering ETDs
Additive manufacturing, also known as 3D printing, is an innovative technique that is increasing its popularity in many industries including construction. 3D printing is related to the layer wised manufacturing or additive construction of any simple to intricate geometry from a digital file. The construction industry has a high potential for using 3D printing technology. However, one of the critical factors in the adaption of additive manufacturing in the construction industry is achieving a printable concrete mix design. This research aims to design printable mixes of lightweight concrete that could be effectively used in the 3D printing of walls or …
The Impact Of Albuquerque’S Bus Rapid Transit System On Pedestrian Safety, Martina Mercure
The Impact Of Albuquerque’S Bus Rapid Transit System On Pedestrian Safety, Martina Mercure
Civil Engineering ETDs
This project will explore the impacts of several traffic safety countermeasures and roadway design changes on pedestrian safety along the Central Avenue corridor of Albuquerque, New Mexico. The motivation behind this research is the communities concern for the increase in pedestrian fatalities in the US and specifically New Mexico. The research will have a specific focus on pedestrian safety, but we will also address traffic safety outcomes for motor vehicle users and bicyclists. The City of Albuquerque has taken note of the traffic safety issues on Central Avenue and has implemented or is in the process of implementing several countermeasures …
Additive Manufacturing Of Engineered Cementitious Composites With Ultra-High Tensile Ductility, Amir Bakhshi
Additive Manufacturing Of Engineered Cementitious Composites With Ultra-High Tensile Ductility, Amir Bakhshi
Civil Engineering ETDs
One of the critical factors in the development of additive manufacturing in the construction industry is designing suitable materials for 3D printing applications. 3D concrete printing (3DCP) has gained significant attention due to the abundance and availability of concrete. However, concrete is a brittle material and, without proper reinforcement, cannot meet the requirements for structural purposes. Engineered Cementitious Composites (ECC), known for high ductility, and strain-hardening with low fiber contents, can potentially eliminate the need for steel reinforcement in 3D printing without any need for manual placement of reinforcement. A set of systematic tests on ECC mix designs' fresh and …