University of Pennsylvania
Universidad de La Salle, Bogotá
Cornell University
University of Nebraska - Lincoln
Technological University Dublin
Santa Clara University
California Polytechnic State University, San Luis Obispo
Physical And Stochiometric Controls On Nutrient Uptake And Ecosystem Respiration In Contrasting Sites,
2024
University of New Mexico
Physical And Stochiometric Controls On Nutrient Uptake And Ecosystem Respiration In Contrasting Sites, Jancoba K. Dorley
Civil Engineering ETDs
Meteorological, hydrological, and biogeochemical processes naturally control stream ecosystems. These processes define the frequency and distribution of precipitation and the supply and demand of solutes and particles to support aquatic food chains through space and time. Studies have also found that stream ecosystems are also controlled by anthropogenic activities, which occur on a much shorter timescale. These anthropogenic activities affect stream ecosystems' structure and function from local to planetary changes to the environment. It is essential for scientists and engineers to understand the relationships between naturally occurring processes and those created by human activities for a better interpretation of stream …
Modeling And Understanding Dispute Causation In The Us Public-Private Partnership Projects,
2024
Missouri University of Science and Technology
Modeling And Understanding Dispute Causation In The Us Public-Private Partnership Projects, Mohamad Abdul Nabi, Rayan H. Assaad, Islam H. El-Adaway
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The partnership between the public and private sectors has led to a new and innovative way of delivering infrastructure projects that is referred to as public-private partnership (PPP). There are various benefits associated with PPP delivery methods including risk sharing, access to private funding, innovation, and flexibility, among others. Despite the proved benefits, contract conflicts and disputes are very common in PPP projects. While previous research studies examined the risks and the potential causes of conflicts in PPP projects, little-to-no research efforts were directed to study and model the interconnectivities between the different causes of conflicts in PPP agreements. To …
Hanford Low-Activity Waste Vitrification: A Review,
2024
Missouri University of Science and Technology
Hanford Low-Activity Waste Vitrification: A Review, José Marcial, Brian J. Riley, Albert A. Kruger, Charmayne E. Lonergan, John D. Vienna
Materials Science and Engineering Faculty Research & Creative Works
This Paper Summarizes the Vast Body of Literature (Over 200 Documents) Related to Vitrification of the Low-Activity Waste (LAW) Fraction of the Hanford Tank Wastes. Details Are Provided on the Origins of the Hanford Tank Wastes that Resulted from Nuclear Operations Conducted between 1944 and 1989 to Support Nuclear Weapons Production. Waste Treatment Processes Are Described, Including the Baseline Process to Separate the Tank Waste into LAW and High-Level Waste Fractions, and the LAW Vitrification Facility Being Started at Hanford. Significant Focus is Placed on the Glass Composition Development and the Property-Composition Relationships for Hanford LAW Glasses. Glass Disposal Plans …
A Vehicle-Bridge Interaction Model Considering Contact Patch Size And Vehicle Self-Generated Excitation – A Theoretical Study,
2024
Missouri University of Science and Technology
A Vehicle-Bridge Interaction Model Considering Contact Patch Size And Vehicle Self-Generated Excitation – A Theoretical Study, Zhenhua Shi, Yahya M. Mohammed, Nasim Uddin, Genda Chen
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This paper presents an improved theoretical damped single-axle vehicle-bridge dynamic interaction model to consider the effect of the contact patch size and motor-induced vehicle excitation. The contact patch issue is critical as it determines the minimum time step for simulation and maximum identifiable frequency, while the inclusion of the motor-induced vehicle excitation benefits the design of autonomous self-driven rather than towed vehicles. Estimations of the contact patch size for both the pneumatic tire and solid wheel scenarios are discussed. The contact patch responses, which degenerate into contact point responses when the contact patch size is assumed to be infinitely small, …
A Political Theory Of Engineered Systems And A Study Of Engineering And Justice Workshops,
2024
Dartmouth College
A Political Theory Of Engineered Systems And A Study Of Engineering And Justice Workshops, Dominic David Carrese
Dartmouth College Master’s Theses
Since there are good reasons to think that some engineered systems are socially undesirable—for example, internal combustion engines that cause climate change, algorithms that are racist, and nuclear weapons that can destroy all life—there is a well-established literature that attempts to identify best practices for designing and regulating engineered systems in order to prevent harm and promote justice. Most of this literature, especially the design theory and engineering justice literature meant to help guide engineers, focuses on environmental, physical, social, and mental harms such as ecosystem and bodily poisoning, racial and gender discrimination, and urban alienation. However, the literature that …
Two-Group Drift-Flux Model For Dispersed Gas-Liquid Flow In Large-Diameter Pipes,
2024
Missouri University of Science and Technology
Two-Group Drift-Flux Model For Dispersed Gas-Liquid Flow In Large-Diameter Pipes, Hossein Barati, Takashi Hibiki, Joshua P. Schlegel, Naofumi Tsukamoto
Nuclear Engineering and Radiation Science Faculty Research & Creative Works
Interfacial Heat and Mass Transfer Are Prevalent in Industrial Processes. the Interfacial Transfer Rate Can Be Obtained by the Product of their Fluxes and Interfacial Area Concentration (IAC) Calculated by the Interfacial Area Transport Equation (IATE). Bubbles Show Different Behavior According to their Sizes. Hence, Bubbles Are Classified into Two Groups. Consequently, Two-Group IATE is Required Causing to Use of Two Gas Momentum Equations Leading to More Complexity. the Present Study Suggests a New Reliable Two-Group Drift-Flux Modeling to Reduce the Two Gas Momentum Equations to One Gas Mixture Momentum Equation for Gas-Liquid Flow in Large-Diameter Pipes. the Model is …
Insights Into The Intrinsic Asymmetry Of Bluff-Body Stabilised Swirling And Non-Swirling Annular Flows,
2024
Edith Cowan University
Insights Into The Intrinsic Asymmetry Of Bluff-Body Stabilised Swirling And Non-Swirling Annular Flows, Syed E. Gillani, Yasir Al-Abdeli
Research outputs 2022 to 2026
Bluff-body stabilised annular jets possess simple, well-defined, axisymmetric geometry, yet exhibit highly complex flow fields, are susceptible to asymmetry at larger blockage ratios, and embody both complex zones and shear layers. Practical annular combustors feature swirl and a central jet which further complicates the flows. Despite the importance of asymmetry in practical combustor design, a systematic investigation for the role of flow regime (transitional, turbulent), Reynolds number, swirl number, or central jets on asymmetry remains lacking. In this study, two-dimensional time-averaged planar particle image velocimetry measurements are conducted to resolve the intrinsic asymmetry associated in transitional (Res = 2700) and …
Data-Driven Analysis Of Progressive Design Build In Water And Wastewater Infrastructure Projects,
2024
Missouri University of Science and Technology
Data-Driven Analysis Of Progressive Design Build In Water And Wastewater Infrastructure Projects, Fareed Salih, Radwa Eissa, Islam H. El-Adaway
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The United States has invested heavily in water and wastewater infrastructure projects to address growing demand and aging systems. To ensure the effective delivery of these projects, agencies are shifting toward alternative delivery methods such as progressive design build (PDB), which has demonstrated accelerated schedule and enhanced cost performance across the literature as well as multiple projects compared to traditional DB. This has raised a need for evaluating PDB's state of adoption and performance in the water and wastewater sector. To this end, the authors: (1) conducted descriptive and statistical analyses of the 21 PDB water and wastewater projects available …
Performance Of Smart Shear Keys In Concrete Bridges Under Tsunami Loading: An Experimental Study,
2024
Missouri University of Science and Technology
Performance Of Smart Shear Keys In Concrete Bridges Under Tsunami Loading: An Experimental Study, Haibin Zhang, Xinzhe Yuan, Genda Chen, Pedro Lomonaco
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Bridges have recently been exposed to an increasing number of natural hazards such as earthquakes and tsunamis. These extreme events have resulted in transverse offsets, overturning moments, and even dropping-off of superstructures due to their weak connection to substructures. These outcomes are potentially prevented or mitigated by developing and deploying sliding, modular, adaptive, replaceable, and two-dimensional (SMART) shear keys as fuse elements between superstructures and substructures. The novelty of SMART shear keys is to enable an adaptive control of both the force and displacement of bridges under different types of loads. In this study, the performance of SMART shear keys …
The Hydration, Microstructure, And Mechanical Properties Of Vaterite Calcined Clay Cement (Vc³),
2024
Missouri University of Science and Technology
The Hydration, Microstructure, And Mechanical Properties Of Vaterite Calcined Clay Cement (Vc³), Yaqiang Li, Yue Li, Hongyan Ma, Jiaqi Li
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Limestone (calcite) calcined clay cement (LC3) is a promising low-CO2 binder, but the low activity of calcite cannot compensate the reduction in clinker factor, resulting in low one-day strength and limiting its broad applications. As recent carbon capture and utilization technologies allow scalable production of vaterite, a more reactive CaCO3 polymorph, we overcome the challenge by introducing vaterite calcined clay cement (VC3), inspired by the vaterite-calcite phase change. In the present study, VC3 exhibits higher compressive strengths and faster hydration than LC3. Compared to hydrated LC3, hydrated VC3 exhibits increased amount of hemi- and mono-carboaluminate formation and decreased amount of …
Xylan Fast Pyrolysis: An Experimental And Modelling Study Of Particle Changes And Volatiles Release,
2024
Ruhr University Bochum, Germany
Xylan Fast Pyrolysis: An Experimental And Modelling Study Of Particle Changes And Volatiles Release, F Cerciello, E Freisewinkel, A Coppola, C Ontyd, D Tarlinski, Martin Schiemann, Osvalda Senneca, Pierro Salatino, C Allouis, Victor Scherer, Thomas H. Fletcher
Faculty Publications
Biomass char particles produced by pyrolysis may have different morphologies, which has important implications on burning mode, conversion rate and boiler efficiency. These features are difficult to address due to the complexity of biomass structure and pyrolysis reaction models. The present work reports preliminary results on the morphological changes and volatile release that solid particles of Xylan experience upon fast heating in a Drop Tube Reactor (DTR) and in a Heated Strip Reactor (HSR) in a range of temperature between 1100 and 1573 K under inert atmosphere with heating rate in the order of 103 K/s. Two different Xylan …
External Direct Sum Invariant Subspace And Decomposition Of Coupled Differential-Difference Equations,
2024
Southern Illinois University Edwardsville
External Direct Sum Invariant Subspace And Decomposition Of Coupled Differential-Difference Equations, Keqin Gu, Huan Phan-Van
SIUE Faculty Research, Scholarship, and Creative Activity
This article discusses the invariant subspaces that are restricted to be external direct sums. Some existence conditions are presented that facilitate finding such invariant subspaces. This problem is related to the decomposition of coupled differential-difference equations, leading to the possibility of lowering the dimensions of coupled differential-difference equations. As has been well documented, lowering the dimension of coupled differential-difference equations can drastically reduce the computational time needed in stability analysis when a complete quadratic Lyapunov-Krasovskii functional is used. Most known ad hoc methods of reducing the order are special cases of this formulation.
Skilled Worker Shortage Across Key Labor-Intensive Construction Trades In Union Versus Nonunion Environments,
2024
Missouri University of Science and Technology
Skilled Worker Shortage Across Key Labor-Intensive Construction Trades In Union Versus Nonunion Environments, Tamima Elbashbishy, Islam H. El-Adaway
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Skilled labor plays a crucial role in ensuring that construction projects are completed on time, within budget, and to the required standards of quality and safety. However, the construction industry has been facing a labor shortage in recent years, which poses a significant challenge to the industry's growth and sustainability. Therefore, it is important to examine the characteristics of the construction skilled labor market to understand the factors that contribute to the shortage of skilled workers and develop strategies to address the issue. This paper fills this knowledge gap. To this end, the authors (1) collected and processed project documentation …
A Holistic Approach To Exploring The Root Factors Of Work Zone Accidents,
2024
Missouri University of Science and Technology
A Holistic Approach To Exploring The Root Factors Of Work Zone Accidents, Bahaa Chammout, Muaz O. Ahmed, Islam H. El-Adaway, William Lieser
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Work zones are crucial for infrastructure maintenance and improvement. However, ongoing projects within work zones sometimes can place workers and drivers in dangerous situations. Despite safety regulations, work zone accidents persist with notable severity and frequency. Previous research has explored work zone accident causation, but it has not provided a comprehensive understanding of the factors that impact work zone safety. This paper addresses this research gap by following a multistep methodology. First, a systematic literature review (SLR) was conducted to identify a comprehensive list of 37 factors impacting work zone safety. Second, social network analysis (SNA) was employed to analyze …
Enhancing Wettability Prediction In The Presence Of Organics For Hydrogen Geo-Storage Through Data-Driven Machine Learning Modeling Of Rock/H2/Brine Systems,
2023
Edith Cowan University
Enhancing Wettability Prediction In The Presence Of Organics For Hydrogen Geo-Storage Through Data-Driven Machine Learning Modeling Of Rock/H2/Brine Systems, Zeeshan Tariq, Muhammad Ali, Nurudeen Yekeen, Auby Baban, Bicheng Yan, Shuyu Sun, Hussein Hoteit
Research outputs 2022 to 2026
The success of geological H2 storage relies significantly on rock–H2–brine interactions and wettability. Experimentally assessing the H2 wettability of storage/caprocks as a function of thermos-physical conditions is arduous because of high H2 reactivity and embrittlement damages. Data-driven machine learning (ML) modeling predictions of rock–H2–brine wettability are less strenuous and more precise. They can be conducted at geo-storage conditions that are impossible or hazardous to attain in the laboratory. Thus, ML models were utilized in this research to accurately model the wettability behavior of a ternary system consisting of H2, rock minerals (quartz and mica), and brine at different operating geological …
The Need For Energy Storage On Renewable Energy Generator Outputs To Lessen The Geeth Effect, I.E. Short-Term Variations Mainly Associated With Wind Turbine Active Power Output,
2023
Technological University Dublin
The Need For Energy Storage On Renewable Energy Generator Outputs To Lessen The Geeth Effect, I.E. Short-Term Variations Mainly Associated With Wind Turbine Active Power Output, Tony Kealy
Articles
Many studies investigating the short-term variations associated with the power output from wind turbine generators utilise simulated or modelled data in the analysis. This current study uses short-term empirical data downloaded directly from operational wind turbines via electrical power quality meters. The empirical data shows that the short-term variations (one-second or sub-one-second timeframe) occur continuously over most of the power output range. A novel name is proposed, the Geeth Effect, for this variability phenomenon. The Geeth Effect is measured using the coefficient of variation mathematical expression and is likely contributing to (i) lower-than-expected financial and environmental benefits associated with …
Prediction Of Self-Consolidating Concrete Properties Using Xgboost Machine Learning Algorithm: Part 1–Workability,
2023
Missouri University of Science and Technology
Prediction Of Self-Consolidating Concrete Properties Using Xgboost Machine Learning Algorithm: Part 1–Workability, Amine El Mahdi Safhi, Hamed Dabiri, Ahmed Soliman, Kamal Khayat
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The Interest in Implementing Self-Consolidating Concrete (SCC) in Major Construction Projects Has Increased Significantly in Recent Years. This Paper Reports the Results of an Extensive Survey of Experimental Data of More Than 1700 SCC Mixtures from over 100 Studies Published in the Last Decade. the Survey Included the SCC Mixture Proportioning, Key Fresh Properties Including Flowability, Passing Ability, and Segregation Resistance, as Well as Some of the Derived Properties (E.g., Paste Volume). the Statistical Analysis of the Reported Parameters Showed Wide Variations in Values. the Outcome of the Survey Indicates that SCC Mixture Design and Workability Properties Do Not Systematically …
Design And Performance Of Fiber-Reinforced Shrinkage Compensating Eco-Friendly Concrete,
2023
Missouri University of Science and Technology
Design And Performance Of Fiber-Reinforced Shrinkage Compensating Eco-Friendly Concrete, Kamran Aghaee, Kamal Khayat
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Eco-Crete is an ecological and economical concrete that benefits from high packing density of solid materials and reduced paste. Eco-Crete can enhance the service life of structures by reducing the risk of shrinkage cracking. In this study, shrinkage mitigating materials included an expansive agent (EA), a shrinkage reducing admixture (SRA), and a lightweight sand (LWS), as well as steel and synthetic fibers were used to minimize the risk of cracking. A total of 35 fiber-reinforced Eco-Crete mixtures were prepared with 350 kg/m3 of cementitious materials and 55 % substitution of fly ash and slag. Key fresh and mechanical properties in …
Experimental Investigation Of Temperature Polarisation By Capturing The Temperature Profile Development Over Dcmd Membranes,
2023
Edith Cowan University
Experimental Investigation Of Temperature Polarisation By Capturing The Temperature Profile Development Over Dcmd Membranes, Hiras Ahamed Hijaz, Masoumeh Zargar, Abdellah Shafieian, Amir Razmjou, Mehdi Khiadani
Research outputs 2022 to 2026
Temperature polarisation (TP) is a major drawback limiting the global acceptance of membrane distillation (MD) technology. TP is typically quantified using a dimensionless index known as Temperature Polarisation Coefficient (TPC). TPC has significant limitations, whereby it cannot be used to compare different MD configurations or design conditions, nor to analyse the TP phenomenon along the membrane. In this research, the temperature profile over and along a lengthy DCMD membrane has been measured under various operational conditions, where its impact on TP has been explored for the first time. A specialised DCMD membrane cell was manufactured to capture temperature profiles, both …
Tapping The Hourglass: Disequilibrium Relaxation Following Accelerated Nuclear Decay,
2023
Unaffiliated
Tapping The Hourglass: Disequilibrium Relaxation Following Accelerated Nuclear Decay, Nathan Mogk
Proceedings of the International Conference on Creationism
In 2005, the Radioisotopes and the Age of The Earth (RATE) research initiative published compelling evidence for at least one episode of past radioactive decay which was accelerated by orders of magnitude compared with the rates measured in recent years. Constancy of radioactive decay rates is a central assumption in radiometric dating. Accelerated nuclear decay (AND) causes systematic change in the results of radiometric dating beyond the in situ above normal accumulation of daughter products. This includes relaxation of magma reservoirs to equilibrium and excessive inheritance arising from disequilibrium excesses of daughter products of greater order than crystal-melt partition ratios. …
