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2024

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Articles 31 - 60 of 66

Full-Text Articles in Geotechnical Engineering

Enhanced Hoek-Brown (H-B) Criterion For Rocks Exposed To Chemical Corrosion, Hao Li, Leo Pel, Zhenjiang You, David Smeulders May 2024

Enhanced Hoek-Brown (H-B) Criterion For Rocks Exposed To Chemical Corrosion, Hao Li, Leo Pel, Zhenjiang You, David Smeulders

Research outputs 2022 to 2026

Underground constructions often encounter water environments, where water–rock interaction can increase porosity, thereby weakening engineering rocks. Correspondingly, the failure criterion for chemically corroded rocks becomes essential in the stability analysis and design of such structures. This study enhances the applicability of the Hoek-Brown (H-B) criterion for engineering structures operating in chemically corrosive conditions by introducing a kinetic porosity-dependent instantaneous mi (KPIM). A multiscale experimental investigation, including nuclear magnetic resonance (NMR), X-ray diffraction (XRD), scanning electron microscopy (SEM), pH and ion chromatography analysis, and triaxial compression tests, is employed to quantify pore structural changes and their linkage with the strength responses …


Development Of Earthquake Hazard Prediction Software For South Carolina And Its Applications, Vishnu Saketh Jella May 2024

Development Of Earthquake Hazard Prediction Software For South Carolina And Its Applications, Vishnu Saketh Jella

All Dissertations

This dissertation presents the development of earthquake hazard generation software, CarolinaShake and CarolinaADRS, for the state of South Carolina and its applications in the field of earthquake engineering. South Carolina is a seismically active state in the eastern United States, and there is a need to accurately quantify the earthquake hazard and incorporate it into the design of infrastructure systems. To achieve this objective, the South Carolina Department of Transportation (SCDOT) is actively supporting the initiatives to update its seismic design policies and procedures of civil infrastructure systems. As part of those initiatives, first, CarolinaShake, a Windows-based graphical user interface …


Development And Application Of Discrete Element Models For Granular Materials - From Rigid Spheres To Complex-Shaped Flexible Particles With Breakage, Zakia Tasnim May 2024

Development And Application Of Discrete Element Models For Granular Materials - From Rigid Spheres To Complex-Shaped Flexible Particles With Breakage, Zakia Tasnim

All Dissertations

Granular materials, which can range from nanometers to centimeters, are widely encountered as particles or powders in nature and in engineered systems. Some examples of granular materials include sands, gravels, biomass feedstocks, rice grains, pharmaceutical pills, glass beads, and lunar or martian regolith simulants. The attributes of and the interactions between constituent particles dictate the bulk mechanical properties and behavior of granular materials. The discrete element method (DEM), a particle-based modeling technique, has become a useful numerical tool for modeling the bulk behavior (such as mechanical, flow, and breakage behavior) of granular materials, where interactions between the granular materials' individual …


Causes And Consequences Of Inefficient Drilling And Blasting In Mine Development Headings: A Case Study Of Hard Rock Gold Mining Operations In Northern Tanzania, George Bennett Apr 2024

Causes And Consequences Of Inefficient Drilling And Blasting In Mine Development Headings: A Case Study Of Hard Rock Gold Mining Operations In Northern Tanzania, George Bennett

Tanzania Journal of Engineering and Technology (TJET)

Despite the introduction of the perimeter blasting technique at the Tulawaka Gold Mine, the mine continued to suffer from an overbreak of mine development headings, with an average overbreak of 24% every 22 m, which is approximately twice the acceptable 10% overbreak. The causes of this problem include ineffective drilling practices and uneven and excessive charging of explosives, resulting in a slightly high powder factor of 3.94 kg/m3 instead of 3.8 kg/m3, as per the design. The problem of overbreak resulted in ore dilution, a longer mine development cycle time and additional costs of approximately US$ 45 per cut, especially …


Assessment Of Improvement In Unpaved Roadway Performance Using 3d Geogrids Under Cyclic Loading, Munibhaskar Pagadala Apr 2024

Assessment Of Improvement In Unpaved Roadway Performance Using 3d Geogrids Under Cyclic Loading, Munibhaskar Pagadala

Doctoral Dissertations and Master's Theses

Geogrids have been used for decades to improve the performance in both paved and unpaved road construction. This research focuses on quantifying the performance and optimizing the design of unpaved roadways using the results from an extensive cyclic triaxial testing program. Twenty-seven cyclic triaxial tests were performed, consisting of unreinforced (control) and reinforced samples using two types of 3D geogrids: Grid1 and Grid2. The samples measured 150 mm in diameter and a height of 300 mm. The tests were run under different loading sequences ranging from 41 kPa to 55 psi (6 psi to 8 psi of confining stress and …


Performance Assessment Of Microencapsulated Phase Change Materials With Low To High Thermoregulation Range In Asphalt Binder, Anil Kumar Baditha, Ayyaz Fareed Mar 2024

Performance Assessment Of Microencapsulated Phase Change Materials With Low To High Thermoregulation Range In Asphalt Binder, Anil Kumar Baditha, Ayyaz Fareed

Graduate Student and Postdoctoral Fellow Symposium

Asphalt pavements face significant challenges due to low temperature cracking and rutting caused by extreme temperature fluctuations and traffic loading. These issues result in higher maintenance costs and reduced service life of the pavements. To address this, researchers explored the use of Microencapsulated Phase Change Materials (MPCMs) to induce thermoregulation in asphalt pavements. However, the existing research focused on high-temperature performance of binders, highlighting the need of research on evaluating the low-temperature performance. Therefore, the study aims to evaluate the impact of incorporating MPCMs on low to high temperature performance of binders. Three types of MPCMs were incorporated into asphalt …


Numerical Study Of Cone Penetration In Calcareous Sands: Investigating Cone Tip Resistance Correction Factors For Crushable Soils, Stephanie Michelle Hyder Mar 2024

Numerical Study Of Cone Penetration In Calcareous Sands: Investigating Cone Tip Resistance Correction Factors For Crushable Soils, Stephanie Michelle Hyder

Dissertations and Theses

The cone penetration test (CPT) is used to characterize the behavior and properties of soils, including the susceptibility to earthquake liquefaction triggering. The cone tip resistance relates to liquefaction susceptibility through relative density, where relative density is closely related to both cone tip resistance and liquefaction susceptibility. Currently, published methods of estimating liquefaction potential (i.e., cyclic resistance ratio) are based on silica sands and do not properly characterize calcareous sands. The measured cone tip resistance in calcareous sands is lower than in silica sands at the same relative density; this difference is generally attributed to the higher compressibility of calcareous …


Demystifying Utility Coordination: Understanding The Basics, Josshe I. Palm Mar 2024

Demystifying Utility Coordination: Understanding The Basics, Josshe I. Palm

Purdue Road School

This session will explain utility coordination to non-utility coordinators. It will help educate others about the role and responsibilities of a utility coordinator, an OSA, easy UC and design mistakes to avoid, scope and design considerations, items commonly overlooked, when to coordinate SUE, and how to work with your UC to request a letting adjustment. We will also highlight UC submittals and allow time for questions about the UC’s role in a project’s success.


Pcor Partnership Atlas, Wesley D. Peck, Kari Suedel, Kyle A. Glazewski, Kevin C. Connors, James A. Sorensen, Charles D. Gorecki, Brian P. Kalk, John A. Harju Mar 2024

Pcor Partnership Atlas, Wesley D. Peck, Kari Suedel, Kyle A. Glazewski, Kevin C. Connors, James A. Sorensen, Charles D. Gorecki, Brian P. Kalk, John A. Harju

EERC Maps and Infographics

The Plains CO2 Reduction (PCOR) Partnership Atlas provides a profile of CO2 sources and potential storage locations across the PCOR Partnership region. The revised sixth edition of the Atlas provides an up-to-date look at PCOR Partnership initiative activities, including additional regional characterization and updates on commercial projects. Additional background information on carbon capture, utilization, and storage (CCUS) is included to give a better understanding of how CCUS addresses concerns about climate change while allowing future energy needs to be met.


Soil Nitrate Prediction Using Ftir-Atr, Vis-Nir, And Raman Spectroscopy, Sabiha Ferdous Mar 2024

Soil Nitrate Prediction Using Ftir-Atr, Vis-Nir, And Raman Spectroscopy, Sabiha Ferdous

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Fourier transform infrared spectroscopy (FTIR) combined with Attenuated total reflectance (ATR), Visible-Near Infrared spectroscopy (Vis-NIR), and Raman spectroscopy (RS) are non-destructive techniques for rapid determination of nitrogen compounds in soil. Leveraging FTIR-ATR and Vis-NIR spectra using partial least squares regression (PLSR) modeling, the study aims to predict soil nitrate content and explored the feasibility of Raman spectroscopy to detect nitrate (NO3-), nitrite (NO2-), and ammonium (NH4+) in soil. Soil samples were collected from four different fields, dried, sieved (2mm), and then used for collecting spectra (FTIR-ATR and Vis-NIR). Laboratory analysis was …


Selection Of Soil Stabilization Methods For Low-Volume Road Applications, Peter J. Spinks Mar 2024

Selection Of Soil Stabilization Methods For Low-Volume Road Applications, Peter J. Spinks

Theses and Dissertations

This study examines a potential method of selecting an ideal soil additive to assist road planners in selecting an ideal soil stabilizer for low-volume road construction with in-situ soils. Essential for the socioeconomic success of rural communities, low-volume soil or gravel roads account for approximately 54% of US road expenditures to maintain and remediate. Soil stabilization can provide significant savings in regards to the cost, effectiveness, and environmental impacts of these roads. With hundreds of commercially available soil treatment products available with significant variations to their effects, it can be difficult for road planners to select the most appropriate product. …


Measurements Of The Effective Stress Coefficient For Elastic Moduli Of Sandstone In Quasi-Static Regime Using Semiconductor Strain Gauges, Vassily Mikhaltsevitch, Maxim Lebedev Feb 2024

Measurements Of The Effective Stress Coefficient For Elastic Moduli Of Sandstone In Quasi-Static Regime Using Semiconductor Strain Gauges, Vassily Mikhaltsevitch, Maxim Lebedev

Research outputs 2022 to 2026

Numerous experimental and theoretical studies undertaken to determine the effective stress coefficient for seismic velocities in rocks stem from the importance of this geomechanical parameter both for monitoring changes in rock saturation and pore pressure distribution in connection with reservoir production, and for overpressure prediction in reservoirs and formations from seismic data. The present work pursues a task to determine, in the framework of a low-frequency laboratory study, the dependence of the elastic moduli of n-decane-saturated sandstone on the relationship between pore and confining pressures. The study was conducted on a sandstone sample with high quartz and notable clay content …


Geodatabase And Modeling Code Used For Dynamic Landslide Hazard Maps In Eastern Kentucky, Nathaniel O'Leary, L. Sebastian Bryson Jan 2024

Geodatabase And Modeling Code Used For Dynamic Landslide Hazard Maps In Eastern Kentucky, Nathaniel O'Leary, L. Sebastian Bryson

Earth and Environmental Sciences Research Data

We developed spatiotemporal landslide hazard maps (LHMs) using soil, hydrologic, and geomorphic parameters from the subaerial infinite slope factor of safety (FS) equation under unsaturated conditions. Soil properties were extracted from the NRCS WSS, while geomorphic variables were derived from a 1.5 m LiDAR-based DEM and ArcGIS Online. Soil moisture from Hydrus-1D, driven by precipitation and evapotranspiration (ET) data from Irrigation Manager, introduced temporal variability. Validation against known landslide sites showed spatial and temporal FS accuracy despite some false positives. We also developed a landslide susceptibility maps (LSM) after comparing three machine learning algorithms, with bagged trees achieving the highest …


Performance Of Finned Pile Under Torsional Load In Sand, Aalaa Khater, Ahmad Nasr Prof, Waseim Azzam Prof Jan 2024

Performance Of Finned Pile Under Torsional Load In Sand, Aalaa Khater, Ahmad Nasr Prof, Waseim Azzam Prof

Journal of Engineering Research

The pile foundations can experience torsional loads from earthquakes, wind, waves, offshore wind turbines, electrical transmission towers, and ship collisions in the maritime environment. Additionally, the axial load from the supporting superstructures can also cause torsional loads. This paper presents a new approach to pile modification called the finned pile. To enhance the torsional capacity of a single pile in the sand (where sand was used in a state of medium density Dr=50%), with or without fins, a number of experimental tests were conducted to investigate the effects of torsional loads (T), these studies involved varying the length, width, shape, …


Soil Improvement Using Fungal Mycelium Of Trichoderma Virens And Construction Techniques Of Mud Dauber, Park Joon Soo Jan 2024

Soil Improvement Using Fungal Mycelium Of Trichoderma Virens And Construction Techniques Of Mud Dauber, Park Joon Soo

LSU Doctoral Dissertations

Traditional ground improvement techniques involve high energy consumption and expensive and invasive earthworks. To develop sustainable ground improvement techniques, extensive research has explored biological processes and strategies. This dissertation identifies two organisms, fungal mycelium and mud dauber wasp, as sources of utilization and inspiration for the development of sustainable soil improvement techniques.

Filamentous fungi can form a root-like interconnected complex network known as fungal mycelium. Fungal mycelium can extend through soil pores and secrete hydrophobic compounds, binding soil particles and increasing soil water repellency. This dissertation conducted experimental studies to investigate the effects of fungal mycelium on hydraulic and mechanical …


Thermo-Mechanical Stability Analysis Of Hollow Cellular Concrete Block Air Convection Embankments For Cold Regions, H. Wu, X. Zhang, J. Liu Jan 2024

Thermo-Mechanical Stability Analysis Of Hollow Cellular Concrete Block Air Convection Embankments For Cold Regions, H. Wu, X. Zhang, J. Liu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Crushed-rock air convection embankment (ACE), as a highly open-graded porous medium, has been used to mitigate the thaw settlement of pavement structures in permafrost regions. Previous studies have revealed that cellular concrete has significant potential as a cost-effective material for ACE to solve the problem of crushed rock shortage in interior Alaska and improved the thermal stability of pavement structures in cold climates. the design configurations of the hollow cellular concrete block ACE were further designed to maximize the performance benefits and facilitate future implementation and field construction. However, the mechanical behaviors of the proposed structures and ice-rich subgrade were …


Prediction Of Stratified Ground Consolidation Via A Physics-Informed Neural Network Utilizing Short-Term Excess Pore Water Pressure Monitoring Data, Weibing Gong, Linlong Zuo, Lin Li, Hui Wang Jan 2024

Prediction Of Stratified Ground Consolidation Via A Physics-Informed Neural Network Utilizing Short-Term Excess Pore Water Pressure Monitoring Data, Weibing Gong, Linlong Zuo, Lin Li, Hui Wang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Predicting stratified ground consolidation effectively remains a challenge in geotechnical engineering, especially when it comes to quickly and dependably determining the coefficient of consolidation ((Formula presented.)) for each soil layer. This difficulty primarily stems from the time-intensive nature of the consolidation process and the challenges in efficiently simulating this process in laboratory settings and using numerical methods. Nevertheless, the consolidation of stratified ground is crucial because it governs ground settlement, affecting the safety and serviceability of structures situated on or in such ground. In this study, an innovative method utilizing a physics-informed neural network (PINN) is introduced to predict stratified …


Evaluation Of Hydrophobic Materials For Stabilizing Expansive Soils, Suman Shrestha Jan 2024

Evaluation Of Hydrophobic Materials For Stabilizing Expansive Soils, Suman Shrestha

Civil Engineering Theses - Archive

The swelling and shrinkage of the expansive soil as a response to moisture change is one of the significant challenges posed to infrastructure projects. The significant economic damage that is caused by the expansive soil, as well as its abundance in nature, has prompted various scientists and engineers all around the world to actively search for new and improved methods for stabilizing it. Various traditional methods, such as lime and cement treatment, have been used extensively to stabilize expansive soils and mitigate their harmful effects on the infrastructure. Although these methods are quite often effective and various studies have been …


Use Of Recycled Plastics To Improve Strength And Reduce Swelling Of Expansive Subgrade, Merina Thapa Jan 2024

Use Of Recycled Plastics To Improve Strength And Reduce Swelling Of Expansive Subgrade, Merina Thapa

Civil Engineering Theses - Archive

Managing solid waste, particularly non-degradable plastics, is a growing environmental concern due to its persistence and limited disposal options. With landfill space dwindling and costs increasing, innovative and sustainable solutions are critical. One promising approach is incorporating plastic waste into construction materials, specifically for subgrade soil stabilization in pavements. This study suggests a method that involves mixing recycled plastic with soil to enhance its properties.

To find out how useful this method is, LDPE, HDPE, PET, and PP plastics were shredded and mixed with soil in different amounts (2%, 3%, 4%, and 5% by weight). Laboratory tests, including compaction, unconfined …


Geodatabase And Automation Code Used For Past And Real-Time Dynamic Landslide Hazard Maps In Eastern Kentucky, Nathaniel O'Leary, L. Sebastian Bryson, Jason M. Dortch Jan 2024

Geodatabase And Automation Code Used For Past And Real-Time Dynamic Landslide Hazard Maps In Eastern Kentucky, Nathaniel O'Leary, L. Sebastian Bryson, Jason M. Dortch

Earth and Environmental Sciences Research Data

We developed spatiotemporal landslide hazard maps (LHMs) using soil, hydrologic, and geomorphic parameters from the subaerial infinite slope factor of safety (FS) equation under unsaturated conditions. Soil properties were sourced from the NRCS WSS, while geomorphic variables were derived from a 1.5 m LiDAR-based DEM and ArcGIS Online. Soil moisture from Hydrus-1D, driven by precipitation and evapotranspiration (ET) data from Irrigation Manager, introduced temporal variability. Validation against known landslide sites demonstrated FS accuracy both spatially and temporally, despite some false positives. To reduce false positives and enhance slope stability representation, novel depth-to-bedrock (DTB) and soil root cohesion maps were incorporated …


Effect Of Admixtures On Rapid Hardening, Self-Consolidating Concrete, Haley Johnson Jan 2024

Effect Of Admixtures On Rapid Hardening, Self-Consolidating Concrete, Haley Johnson

Theses and Dissertations--Civil Engineering

Self-consolidating, rapid-hardening concrete is a sought-after product in the market now, however the effects of admixtures on fresh and hardened concrete rheology are still uncertain. This study aims to create a self-consolidating concrete (SCC) using calcium sulfoaluminate (CSA) cement for its rapid-hardening properties, and tests two set time retarders and two viscosity-modifying admixtures (VMAs) to determine how they affect the properties of concrete. The properties studied in this thesis are workability, viscosity, set times, air content, compressive strength, and freeze-thaw resistance of self-consolidating concrete. It was found that tartaric acid creates a very workable SCC with consistent results regardless of …


Experimental And Numerical Analyses Of Percussion Driven Earth Anchors Under Monotonic Pullout Tests, Mehran Azizian Jan 2024

Experimental And Numerical Analyses Of Percussion Driven Earth Anchors Under Monotonic Pullout Tests, Mehran Azizian

Civil Engineering Dissertations - Archive

This dissertation provides a thorough investigation into the behavior and performance of Percussion-Driven Earth Anchors (PDEAs) during monotonic pullout tests. PDEAs are becoming more commonly utilized in geotechnical engineering because of their effectiveness in installation, ability to bear loads immediately, and minimal disruption to the environment. Despite their advantages, a detailed understanding of their pullout capacity and failure mechanisms remains limited.

The research encompasses both experimental and numerical analyses to bridge this knowledge gap. Experimental tests were conducted using Digital Image Correlation (DIC) techniques to obtain precise measurements of soil and anchor interaction and figure out the failure mechanism. Photogrammetry …


Assessment Of Drainage Characteristics Of Recycled Crushed Concrete Aggregate (Rcca) And Plastic Mix Pavement Base, Amena Begum Jan 2024

Assessment Of Drainage Characteristics Of Recycled Crushed Concrete Aggregate (Rcca) And Plastic Mix Pavement Base, Amena Begum

Civil Engineering Theses - Archive

Recycled Crushed Concrete Aggregate (RCCA) offers a sustainable alternative to natural aggregate in construction, reducing reliance on natural resources and diverting construction and demolition debris from landfills. Similarly, the escalating global plastic waste crisis highlights the need for innovative solutions to address non-biodegradable waste disposal challenges and create opportunities for recycling plastics into value-added applications. This study explores the potential of RCCA mixed with plastic waste, such as HDPE and PP, as a viable substitute for natural aggregates in flexible pavement base layers, with a focus on hydraulic properties and drainage performance to enhance pavement durability.

A comprehensive experimental program …


Estimation Of Mechanical Behavior Of Unsaturated Soils From A Soil-Water Characteristic Curve, Lucas Acheampong Jan 2024

Estimation Of Mechanical Behavior Of Unsaturated Soils From A Soil-Water Characteristic Curve, Lucas Acheampong

Theses and Dissertations--Civil Engineering

The small-strain shear modulus and shear strength are two crucial mechanical behaviors used in the design of geotechnical structures and in the analyses of earth materials subjected to static and dynamic loadings. Traditional testing methods for these parameters are expensive and time-consuming. This research aimed to address these challenges by developing a model based on the inverse relationship between mechanical behavior of unsaturated soils and the soil-water characteristic curve (SWCC). The proposed model integrates a scaling function to align the SWCC with the mechanical property curve. Empirical relationships were established for the scaling function, specifically aligning with the air-entry value …


Geophysical Method Used For The Determination And Prediction Of Soil Strength And Stiffness Parameters, Dabo Adama Jan 2024

Geophysical Method Used For The Determination And Prediction Of Soil Strength And Stiffness Parameters, Dabo Adama

Theses and Dissertations--Civil Engineering

This paper presents the results of an effort to use geophysical measurements such as seismic wave velocities and electrical resistivities to calculate airfield design parameters. The study converts all geophysical measurements to equivalent California Bearing Ratio (CBR) values, comparing CBR values estimated from DCP penetration resistance with CBR values estimated from shear wave velocity and electrical resistivity values. Relationships linking the geophysical measurements to CBR estimates were established using laboratory data and applied to field in-situ measurements. The elastic modulus (E) is the stiffness parameter involved in predicting soil strength and stiffness. This research aims to relate electrical conductivity and …


Visualizing And Automating Past, Real-Time, And Forecast Dynamic Hazard Maps For Shallow Colluvial Landslides In Eastern Kentucky, Nathaniel O'Leary Jan 2024

Visualizing And Automating Past, Real-Time, And Forecast Dynamic Hazard Maps For Shallow Colluvial Landslides In Eastern Kentucky, Nathaniel O'Leary

Theses and Dissertations--Earth and Environmental Sciences

Landslide hazards are a persistent threat to communities and infrastructure in Eastern Kentucky, where steep slopes, shallow colluvial soils, and variable hydrological conditions make slope failures frequent. This thesis presents an integrated approach to landslide hazard mapping (LHM) through the development of dynamic, spatiotemporal LHMs for shallow colluvial landslides. Two studies within this work investigate and refine the use of the Lu and Godt (2008) factor of safety (FS) equation to improve landslide predictions. The first study establishes a novel LHM workflow using Hydrus-1D to simulate soil moisture infiltration and fluctuations from precipitation and evapotranspiration (ET) data. This study also …


Performance And Field Testing Of Geotextiles For Dewatering Rare Earth Element Hydraulic Preconcentrate From Hardrock Amd, Ian R. Bird Jan 2024

Performance And Field Testing Of Geotextiles For Dewatering Rare Earth Element Hydraulic Preconcentrate From Hardrock Amd, Ian R. Bird

Graduate Theses, Dissertations, and Problem Reports (ETD)

As part of ongoing efforts to develop a domestic Rare Earth Elements (REE) supply chain the Hydraulic Preconcentrate (HPC) produced at the Horseshoe bend treatment plant (HsB) was manufactured and evaluated as a potential source for feedstock. After the existing clarifiers on the site were flipped to the desired pH set points, HPC was manufactured and pumped to 24 geobags. The geobags were then passively dewatered to increase the total solids percentage. The geobags evaluated were comprised of: Woven geotextiles, composite (woven and non- woven), and geobags augmented with Capillary Channel Fiber (CCF). Column Filtration Tests (CFTs) were performed onsite …


Kiloton Class Isru Systems For Lo2/Lch4 Propellant Production On The Mars Surface, Steven R. Oleson, Elizabeth Turnbull, Julie Kleinhenz, Wesley Johnson, Ryan Grotenrath, Nicholas Uguccini, Benjamin Abshire, Lee Mason, Thomas Packard, Anthony Colozza, John Z. Gyekenyesi, James Fittje, Stephen Hoffman, Leslie S. Gertsch Jan 2024

Kiloton Class Isru Systems For Lo2/Lch4 Propellant Production On The Mars Surface, Steven R. Oleson, Elizabeth Turnbull, Julie Kleinhenz, Wesley Johnson, Ryan Grotenrath, Nicholas Uguccini, Benjamin Abshire, Lee Mason, Thomas Packard, Anthony Colozza, John Z. Gyekenyesi, James Fittje, Stephen Hoffman, Leslie S. Gertsch

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

As part of the 2023 strategic analysis cycle to explore the trade space, the NASA Mars Architecture Team wanted to explore what it takes to produce in situ on Mars many hundreds of tons of propellants for a large all-chemical transportation system. The conceptual operations and design of the LO2/LCH4 in situ resource utilization (ISRU) water acquisition, propellant production and liquification system was assigned to the NASA Compass concurrent engineering team with support from various NASA ISRU, cryogenic fluid management, and surface power experts. The conceptual point design examined one case producing 300 t of LO2 …


A General Framework For Modeling Subregional Path Effects, T. E. Buckreis, P. Wang, S. J. Brandenberg, J. P. Stewart Jan 2024

A General Framework For Modeling Subregional Path Effects, T. E. Buckreis, P. Wang, S. J. Brandenberg, J. P. Stewart

Civil & Environmental Engineering Faculty Publications

Next Generation Attenuation (NGA) West2 ground motion models (GMMs) include regional path adjustments for broad jurisdictional regions, which necessarily averages spatially variable path effects within those regions. We extend that framework to account for systematic variations in attenuation within subregions defined in consideration of geologic differences. In recent years, cell-based methods which systematically account for spatial variations by summing the attenuation effects over a fine discretization of uniform-rectangular cells (e.g., Dawood and Rodriquez-Marek 2013; Kuehn et al. 2019) have been shown to be an effective alternative to regionalization and a step towards modelling non-ergodic path effects. The main drawbacks of …


Reliability Of Low Frequency Mhvsr Ordinates, F. J. Ornelas, C. C. Nweke, C. A. De La Torre, P. Wang, T. D. Mai, B. R. Cox, S. J. Brandenberg, J. P. Stewart Jan 2024

Reliability Of Low Frequency Mhvsr Ordinates, F. J. Ornelas, C. C. Nweke, C. A. De La Torre, P. Wang, T. D. Mai, B. R. Cox, S. J. Brandenberg, J. P. Stewart

Civil & Environmental Engineering Faculty Publications

Microtremor horizontal-to-vertical spectral ratios (mHVSR) are frequency-dependent ratios of Fourier amplitude spectra of the horizontal to vertical components of a 3-component recording of ambient ground motions from microtremors. Results from mHVSR tests can identify the frequencies associated with site resonances at sites with large impedance contrasts, and hence have potential to provide useful parameters for predicting seismic site response. Site measurements are made by recording ground vibrations either from a temporarily deployed seismometer, typically recording for a relatively short period of time (~1-2 hrs.), or from a permanently-installed broadband seismometer. In this paper, we discuss ongoing work investigating the reliability …