Engineering Commons^™

Transverse Vibration Of Clamped-Pinned-Free Beam With Mass At Free End, Jonathan Hong, Jacob Dodson, Simon Laflamme, Austin Downey

Faculty Publications

Engineering systems undergoing extreme and harsh environments can often times experience rapid damaging effects. In order to minimize loss of economic investment and human lives, structural health monitoring (SHM) of these high-rate systems is being researched. An experimental testbed has been developed to validate SHM methods in a controllable and repeatable laboratory environment. This study applies the Euler-Bernoulli beam theory to this testbed to develop analytical solutions of the system. The transverse vibration of a clamped-pinned-free beam with a point mass at the free end is discussed in detail. Results are derived for varying pin locations and mass values. Eigenvalue …

Elimination Of Empirical, Ineffective And Expensive Pg Plus Tests To Characterize Modified Binders, Zahid Hossain, Ashraf Elsayed, Mm Tariq Morshed, Mohammad Hassan

Publications

For characterizing the polymer modified binders, different state Departments of Transportation (DOTs) use different time consuming and empirical Performance Grade (PG) Plus test methods. Furthermore, the PG Plus tests are silent when asphalt binders are modified with chemicals such as polyphosphoric acid (PPA). But, the effects of the elastomeric or plastomeric polymer are not accurately identified through these conventional tests such as Elastic Recovery (ER) and tenacity. Thus, the main research goal of this study is to recommend alternative test method(s), which can possibly be pursued by using a commonly available device, a Dynamic Shear Rheometer (DSR). Three PG binders …

Use Of Rice Husk Ash (Rha) In Flowable Fill Concrete Mix Material, Zahid Hossain, Kazi Tamzidul Islam

Publications

In the way of finding sustainable development, the flowable fill is a relatively new construction technology. Flowable fill is a self-compacting material, which has been developed in recent years. Flowable fill has been used for different applications such as backfilling walls, sewer trenches, bridge abutments, conduit trenches, pile excavations, and retaining walls. This study examines the potential uses of Rice Husk Ash (RHA) as a sustainable cementitious material (SCM) in the preparation of flowable fill concrete. (RHA is an agricultural by-product of the rice milling process. This study has evaluated the usage of RHA in producing low strength and self-consolidating …

Self-Healing Concrete Using Encapsulated Bacterial Spores In A Simulated Hot Subtropical Climate, Marwa Hassan, Jose Milla, Tyson Rupnow, Ahsennur Soysal

Publications

Bacterial concrete has become one of the most promising self-healing alternatives due to its capability to seal crack widths through microbial induced calcite precipitation (MICP). In this study, two bacterial strains were embedded at varying dosages (by weight of cement) in concrete. Beam specimens were used to identify the maximum crack-sealing efficiency, while cylinder samples were used to determine their effects on the intrinsic mechanical properties, as well as its stiffness recovery over time after inducing damage. The concrete specimens were cured in wet-dry cycles to determine their feasibility in Region 6. The results showed that the specimen groups with …

Karst Sinkhole Detecting And Mapping Using Airborne Lidar, Su Zhang, Shirley Baros, Susan Bogus

Publications

The focus of this study is to detect sinkhole hazards using airborne light detection and ranging (LiDAR) data. The premise is sinkholes, particularly those close to transportation infrastructure assets, could cause substantial damages to infrastructure assets, and therefore, being able to accurately and rapidly detect them is essential. However, it is expensive, time-consuming, labor-intensive, and unsafe to survey sinkholes using conventional ground observation methods. This research project was focused on developing accurate and rapid airborne LiDAR-based sinkhole detection and mapping methods, and transfer the technologies to transportation engineers for implementation and workforce development. The project team also identified best practices …

Decision-Making Tool For Road Preventive Maintenance Using Vehicle Vibration Data, Changbum Ahn, Chao Wang, Jing Du

Publications

Automated and timely road pavement damage inspection is critical to the preventive maintenance and the long-term sustainability and resilience of roads in Region 6. Current road inspection practices rely heavily on a manual process. Sensor-based methods (e.g., LiDAR scanning) are promising but can be too expensive for a wider adoption. This study employs a crowdsourcing approach of using the vibration patterns of regular vehicles in inferring specific types of road damages. A cloud-based smart phone app and system was developed to collect real-time vehicle vibrations, location data, and road damage images for training the detection model. However, there is a …

Strategies For Prioritizing Needs For Accelerated Construction After Hazard Events, Fernando Moreu, Chao Wang, Xinxing Yuan, Laleh Ghanbari, Claudia Garrido

Publications

There is a need for rapid and responsive infrastructure repair and construction after natural disaster events such as hurricanes, wildfires, and tornadoes. These natural disasters often shut down basic infrastructure systems, as experienced recently in several Region 6 states as well as in other states around the country. Accelerated construction practices are often used in these situations to speed up the traditional, and often slow, project delivery process. However, after a natural disaster, several and different types of transportation infrastructure components are in need of inspection, rehabilitation or reconstruction, and transportation agencies are challenged with the task of prioritizing these …

Augmented Reality Enhancing The Inspections Of Transportation Infrastructure: Research, Education, And Industry Implementation, Fernando Moreu, Chris Lippitt, Dilendra Maharjan, Marlon Aguero, Xinxing Yuan

Publications

Transportation infrastructure needs continuous monitoring that is conducted by field inspectors regularly in the field. Currently, infrastructure inspectors climb, measure, and photograph structures annually to inform repair needs and prioritize decisions. In order to promote and accelerate early learner's expertise in decision-making capabilities during infrastructure inspections, this research project developed various software applications using augmented reality (AR) as an inspection tool for bridges and bridge management, more specifically. By objectively quantifying infrastructure field inspections, inspectors can make more accurate field assessments and managers can make better-informed decisions. This project collaborated with stakeholders, national laboratories, DOT agencies such as NCHRP and …

Workforce Development Symposiums For Uhpc, Brad Weldon, Craig Newtson, Grace Mcmurry, Leticia Davila

Publications

Ultra-high performance concrete (UHPC) is a cementitious material with a dense microstructure that contributes to high compressive strengths as well as enhanced durability properties. UHPC also possesses significant post-cracking strength and ductility due to the addition of fibers. These characteristics produce a material that provides advantages over conventional concrete; however, high costs attributed to materials and production, lack of industry familiarity and knowledge, and the absence of standardized design procedures have impeded its widespread use. To help disseminate knowledge on UHPC, two workforce development symposiums on UHPC were held in Las Cruces, New Mexico. The symposiums consisted of presentations and …

Fabrication And Characterization Of Alₓcrcufeni₂ High-Entropy Alloys Coatings By Laser Metal Deposition, Wenyuan Cui, Xinchang Zhang, Lan Li, Yitao Chen, Tan Pan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

High-entropy alloys (HEAs) are becoming new hot spots in the metallic materials community, which are defined to contain equiatomic or close-to-equiatomic compositions. HEAs can possess many interesting mechanical properties, and in particular, they have the great potential to be used as coating materials requiring high hardness and wear resistance. In this study, the feasibility of fabrication AlₓCrCuFeNi₂ (x=0,0.75) HEAs was investigated via laser metal deposition from elemental powders. The microstructure, phase structure, and hardness were studied by an optical microscope, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), electron backscatter diffraction (EBSD) and Vickers hardness tester. The bonding between the …

Predictive Model For Thermal And Stress Field In Selective Laser Melting Process -- Part Ii, Lan Li, Lei Yan, Yitao Chen, Tan Pan, Xinchang Zhang, Wenyuan Cui, Aaron Flood, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Finite Element Analysis (FEA) is used to predict the transient thermal cycle and optimize process parameters to analyze these effects on deformation and residual stresses. However, the process of predicting the thermal history in this process with the FEA method is usually time-consuming, especially for large-scale parts. In this paper, an effective predictive model of part deformation and residual stress was developed for accurately predicting deformation and residual stresses in large-scale parts. An equivalent body heat flux proposed from the single layer laser scan model was imported as the thermal load to the layer by layer model. The hatched layer …

Constellation Planning Methods For Sequential Spacecraft Rendezvous Using Multi-Agent Scheduling, Skylar A. Cox, Nathan B. Stastny, Greg Droge, David K. Geller

Space Dynamics Laboratory Publications

This paper addresses the RPO constellation assignment problem by developing a responsive utility function for tasking a constellation of LEO satellites to several spacecraft servicing tasks. The paper develops the utility function that considers both value of servicing RSO spacecraft in conjunction with the associated ΔV cost. A highly-capable and operationally-relevant task allocation method, called the consensus-based bundle algorithm (CBBA), is leveraged for distributed processing and task allocation. This paper demonstrates that this methodology provides a robust technique for RPO constellation management.

Shoal: Large-Scale Hierarchical Taxonomy Via Graph-Based Query Coalition In E-Commerce, Zhao Li, Xia Chen, Xuming Pan, Pengcheng Zou, Yuchen Li, Guoxian Yu

Research Collection School Of Computing and Information Systems

E-commerce taxonomy plays an essential role in online retail business. Existing taxonomy of e-commerce platformsorganizes items into an ontology structure. However, theontology-driven approach is subject to costly manual maintenance and often does not capture user’s search intention,particularly when user searches by her personalized needsrather than a universal definition of the items. Observingthat search queries can effectively express user’s intention,we present a novel large-Scale Hierarchical taxOnomy viagrAph based query coaLition (SHOAL) to bridge the gapbetween item taxonomy and user search intention. SHOALorganizes hundreds of millions of items into a hierarchicaltopic structure. Each topic that consists of a cluster of itemsdenotes a …

Improving Law Enforcement Daily Deployment Through Machine Learning-Informed Optimization Under Uncertainty, Jonathan David Chase, Duc Thien Nguyen, Haiyang Sun, Hoong Chuin Lau

Research Collection School Of Computing and Information Systems

Urban law enforcement agencies are under great pressure to respond to emergency incidents effectively while operating within restricted budgets. Minutes saved on emergency response times can save lives and catch criminals, and a responsive police force can deter crime and bring peace of mind to citizens. To efficiently minimize the response times of a law enforcement agency operating in a dense urban environment with limited manpower, we consider in this paper the problem of optimizing the spatial and temporal deployment of law enforcement agents to predefined patrol regions in a real-world scenario informed by machine learning. To this end, we …

Direct Assessment Of Entrepreneurial Minded Learning Through Integrated E-Learning Modules, Aadtiyasinh Rana

Master's Theses

Entrepreneurial Minded Learning (EML) has a significant emphasis in engineering education

today. Several approaches have been used to assess the impact of various EML approaches. Many indirect assessment techniques have been used and a few direct assessment techniques have been developed. The work presented in this thesis investigates the effectiveness of two specific measurement methods to quantify entrepreneurial minded learning in students.

The University of New Haven has adopted the approach of integrating e-learning modules on entrepreneurial topics and related contextual activities into courses as the primary approach of developing an entrepreneurial mindset (EM) in students. This study focuses on …

Baja Sae Ecvt Mechanical Design, Tyler Lee Connel, Will Daniel Antes, Matt Stephen Balboni, Benjamin James Colard, Julian Edward Finburgh

Mechanical Engineering

This objective of this project was to design, manufacture, and test the mechanical systems of an electronically-controlled continuously variable transmission (eCVT) for the Cal Poly Baja SAE vehicle.

Pressurized Combustion Product Temperature Measurement Using Integrated Spectral Band Ratios, Scott Cutler Egbert

Theses and Dissertations

With increasing global power demands, there is a growing need for the clean and efficient use of fossil fuel resources. Gas turbine engines are a commonly used means for generating power; from the propulsion of aircraft to electricity on municipal grids. Measuring the temperature within a turbine combustor or at a turbine inlet could provide numerous advantages related to engine control, durability, efficiency, and emissions and yet this relatively straightforward task has eluded turbine engine manufacturers, primarily because of the high temperatures and pressures, harsh environment, and limited access. Optical emissions measurements are of particular interest for this task as …

Discovery And Engineering Of An Endophytic Pseudomonas Strain From Taxus Chinensis For Efficient Production Of Zeaxanthin Diglucoside, Ozkan Fidan, Jixun Zhan

Biological Engineering Faculty Publications

Background

Endophytic microorganisms are a rich source of bioactive natural products. They are considered as promising biofertilizers and biocontrol agents due to their growth-promoting interactions with the host plants and their bioactive secondary metabolites that can help manage plant pathogens. Identification of new endophytes may lead to the discovery of novel molecules or provide new strains for production of valuable compounds.

Results

In this study, we isolated an endophytic bacterium from the leaves of Taxus chinensis, which was identified as Pseudomonas sp. 102515 based on the 16S rRNA gene sequence and physiological characteristics. Analysis of its secondary metabolites revealed …

An Experimental Study Of Thrust Augmentation With Asymmetrical Nozzle Driven Pulsed Ejector, Orlando Rodriguez

Theses and Dissertations

With the emergence of V/STOL vehicles and unmanned aircrafts has come the resurgence of thrust augmentation through an ejector. The use of an ejector has many benefits such as being lightweight and simple design to manufacture. In this study a hot steady jet and a cold steady/unsteady jet was tested. The hot steady jet was produced by a JetCAT PX-180 rxi with a two-inch diameter nozzle exit. The hot steady jet was compared to the cold free steady and unsteady cases. The cold jet was tested under free steady and unsteady condition, as well as steady and unsteady ejector conditions. …

Assessment Of Some Of The Common Practices Used In Scheduling Highway Projects, Jennifer Reyes

Theses and Dissertations

There are several factors documented in the literature that can affect the accuracy of estimated project durations in highway construction, such as weather, location, and soil conditions. Recently, the Texas Department of Transportation (TxDOT) raised a concern regarding some of the practices used when estimating the contract time for projects. This research presents an assessment of the effect that two practices identified have on the estimated project duration. These two practices include: 1) the estimated lead/lag times in project schedules and 2) scheduling with only critical or controlling activities. The effect of these practices is measured, primarily, by using four …

Isogeometric Bezier Dual Mortaring And Applications, Di Miao

Theses and Dissertations

Isogeometric analysis is aimed to mitigate the gap between Computer-Aided Design (CAD) and analysis by using a unified geometric representation. Thanks to the exact geometry representation and high smoothness of adopted basis functions, isogeometric analysis demonstrated excellent mathematical properties and successfully addressed a variety of problems. In particular, it allows to solve higher order Partial Differential Equations (PDEs) directly omitting the usage of mixed approaches. Unfortunately, complex CAD geometries are often constituted by multiple Non-Uniform Rational B-Splines (NURBS) patches and cannot be directly applied for finite element analysis.parIn this work, we presents a dual mortaring framework to couple adjacent patches …

Development And Analysis Of 3d-Printed Synthetic Vocal Fold Models, Ryan Gregory Romero

Theses and Dissertations

Vocal fold models are valuable for studying voice production. They provide an alternative method of studying the mechanics of the voice that does not require in vivo experimentation or the use of excised human or animal tissue. In this thesis, a new method of creating vocal fold models through additive manufacturing is described. The purpose of this research was to reduce model fabrication time, to decrease the number of model failures during manufacturing, and to lay the foundation for creating models with more lifelike geometric and material properties. This research was conducted in four stages. First, a suitable silicone additive …

Improving And Modeling Bacteria Recovery In Hollow Disk System, Clifton Anderson

Theses and Dissertations

Identifying antibiotic resistance in blood infections requires separating bacteria from whole blood. A hollow spinning disk rapidly removes suspended red blood cells by leveraging hydrodynamic differences between bacteria and whole blood components in a centrifugal field. Once the red cells are removed, the supernatant plasma which contains bacteria is collected for downstream antibiotic testing. This work improves upon previous work by modifying the disk design to maximize fractional plasma recovery and minimize fractional red cell recovery. V-shaped channels induce plasma flow and increase fractional plasma recovery. Additionally, diluting a blood sample spiked with bacteria prior to spinning it increased the …

Evaluation And Enhancement Of Carbon Sequestration Potential Of Existing Vegetation Along Roadsides, Vikram Kapoor, Jeffrey Hutchinson, Samer Dessouky

Publications

The objectives of this study were to evaluate the vegetative composition and carbon sequestration potential of vegetation along a major roadway in Texas. Soil and vegetation were evaluated along IH-35 within Bexar County for composition and carbon content. Three 20 m transects were placed at each site and percent vegetative cover was estimated and above ground plant biomass, and soil was collected from three 0.25 m2 subplots along each transect. Plant and soil samples were analyzed for carbon content. Two non-native grasses, bermudagrass and King Ranch bluestem, were the dominant cover at all sites accounting for > 90% coverage at several …

Development Of Metals Corrosion Maps Of Arkansas And Maintenance Of Cross-Drains, Zahid Hossain, Ashraf Elsayed, Mdariful Hasan

Publications

Corrosion potential of metallic structures in alluvial soils is governed by chemical and electromagnetic properties of the soils. Geotechnical engineers are generally more concerned about different types of soils and their physical and mechanical properties than the chemical aspects. The main objective of this study is to analyze the geotechnical, electrochemical and electromagnetic properties of soils in Arkansas. Important parameters (e.g., soil resistivity) related to corrosion potential of metal culverts have been predicted through neural network (NN) models. The developed NN models have been trained and verified by using laboratory test results of soil samples collected from Arkansas Department of …

Assessing The Impacts Of Super Storm Flooding In The Transportation Infrastructure – Case Study: San Antonio, Texas, Marcio Giacomoni, Francisco Olivera, Cesar Do Lago

Publications

Flooding are likely to increase worldwide due to climate change. Large storms, referred here as superstorms, defined as events with return period equal or larger than 100 years, can lead to an increase of property damages and loss of life. The ability to predict and plan for the impacts of superstorms on transportation infrastructure is key to mitigate future damages and losses. This study analyzed 51 combinations of future projections for representative concentration pathways (RCP) 4.5 and 8.5 scenarios, which were used to calculate future 1st and 3rd quartiles, median, minimum and maximum intensity-duration-frequency curves (IDF). A HEC-HMS and GSSHA …

Use Of Bagasse Ash As A Concrete Additive For Road Pavement Application, Gabriel Arce, Marwa Hassan, Maria Gutierrez, Michele Barbato

Publications

The objective of this study was to evaluate the use of sugarcane bagasse ash (SCBA) as a partial replacement of cement in concrete for road pavement application. The study explored the pozzolanic activity of SCBA produced from three different processing methodologies (i.e., raw SCBA, controlled SCBA and post-processed SCBA). The experimental results revealed that SCBA produced by the controlled burning of sugarcane bagasse fiber (SBF) at 650°C and grinding (C-650), presented the maximum pozzolanic activity. However, this SCBA production process was deemed challenging for large-scale industrial application due to low SCBA yield (i.e., 3 to 6%). On the other hand, …

Developing Implementable Climatic Input Data And Moisture Boundary Conditions For Pavement Analysis And Design, Rifat Bulut, Amir Hossein Javid

Publications

The main objective of this study is to develop a practical and implementable numerical model for predicting the moisture (suction) regime within the pavement subgrade system. The research quality and uniformly-dispersed climate data over short distances from Oklahoma Mesonet and the Mitchell based moisture (suction) prediction methods establish the main background of the research study. The study involved numerical modeling and statistical analysis of climatic weather data. The proposed moisture variation model predicts the suction distribution throughout the soil subgrade by solving the diffusion equation and incorporates the measured suction from the Oklahoma Mesonet to estimate the diffusion coefficient. The …

A Comprehensive Framework For Life-Cycle Cost Assessment Of Reinforced Concrete Bridge Decks, Mohamed Soliman, Samir Ahmed, Ligang Shen

Publications

Various environmental and mechanical stressors cause deterioration of concrete bridge decks. Normal wear and tear, freeze and thaw cycles, and chloride penetration due to deicing salts can cause aggressive deterioration that usually require frequent interventions during the life-cycle of the bridge. These interventions include deck maintenance and repairs (e.g., application of sealers or overlay placement) as well as bridge deck replacement. The quantification of the life-cycle cost of bridge decks considering maintenance and repair activities represents a significant challenge facing local and state transportation agencies. The life-cycle maintenance activities not only increase the direct life-cycle cost of the bridge, but …

Portable Roadway High Water Detection System For Driver Safety And Infrastructure Assessment, Hatim Sharif, Samer Dessouky

Publications

The state of Texas, local governments, and community groups are adopting several initiatives to address this problem. The main goal of this project is to develop an approach to enhance prediction and detection of roadway flooding and help efforts to prevent driving into flood roadways. The motivation of this work was initiated by the alarming number of vehicle related flood fatalities in Texas, mostly at low-water crossings. Texas leads the nation in the number of flood fatalities and about 77% of flood fatalities in Texas are motor vehicle-related. This percentage is much higher than the national percentage reported in several …