Graphitic carbon nitride (g-C3N4) has emerged as a promising photocatalyst because of its capability to utilize visible light and more solar energy, low cost in fabrication, great stability, and biocompatibility. However, the poor photocatalytic performance due to various factors and undesired...
Land surface heat and evaporative fluxes exchanged between the land surface and the atmospheric boundary layer play an important role in the climate system. In situ measurements of these fluxes are expensive and available only over a limited number of field experiment sites. At present, the only...
Liquefaction-induced lateral spreading is the permanent lateral deformations developed in gently sloping ground due to a seismic event. The magnitude of the lateral spreading could range from a few millimeters to several meters causing damages to civil infrastructure including bridges, buildings,...
Partially restrained frames can be adopted as secondary lateral load resisting systems in areas of high seismic risk such as California, and as primary systems in areas of low to moderate seismic risk, such as Virginia which experienced an M5.8 earthquake in August of 2011.Taking advantage of...
With the billions of vehicle miles traveled and millions of vehicular collisions occurring annually, collision mitigation and prevention are of top priority. To fully grasp the impact of collision occurrence on roadways, both the macroscopic and microscopic scales need to be addressed. On the...
This dissertation focused on the development of sustainable Pd-based catalysts for the removal of waterborne contaminants (i.e., nitrite and nitrate). It explored different catalyst supports, including electrospun polyacrylonitrile (PAN) nanofibers (NFs), electrospun carbon nanofibers (CNFs), and...
This numerical research studies the effect of considering total body out-of-flatness pattern on design strength of typical steel bridge girders constructed in the United States with the purpose of modifying the current American Welding Society (AWS) out-of-flatness allowances accepted by American...
The increasing demand for wastewater treatment has increased the generation of sewage sludge, thereby increasing the importance of treatment and disposal of sludge in a sustainable manner.Two advanced digestion processes were operated for treatment of municipal sludge for this study: (i) Acid/gas...
The accurate and efficient prediction of hydrodynamic forces and moments on a maneuvering submarine has been achieved by investigating the flow physics involving the interaction of the vortical flow shed from the sail and the cross-flow boundary layer of the hull. In this investigation, a...
This dissertation studies the nucleation mechanisms of ice, clathrate hydrate and silicon clathrate which all belong to tetrahedral materials and carry significant importance to modern society. Because of the stochastic nature and the ultra-fine scale of nucleation, the mechanisms through which...
Abstract of DissertationEvaluation Of Options To Extend Span Range Of Precast Prestressed Concrete Bridge Girders During Preliminary DesignDesign of highway bridges passes through the following two phases: 1- Preliminary design where the design engineer decides on the major artifact type and...
At the present time, the crash safety of new and concept vehicle designs, i.e., with advanced materials or structure or powertrains, is primarily assessed through computer simulations of single-vehicle crash test protocols specified by existing regulations and consumer information programs....
As a multi-phase material, soil exhibits highly nonlinear, anisotropic, and inelastic behavior. While it may be impractical for one constitutive model to address all features of the soil behavior, one can identify the essential aspects of the soil's stress-strain-strength response for a...
It is important to understand the dynamic failure behavior of structures subjected to impact loading in order to improve the survivability. Materials under impact are utterly affected by large deformations, high strain-rates, temperature softening and varying stress-states, which finally may lead...
The State of Kuwait is situated at the northwestern end of the Persian Gulf and has a population of 2.5 million people, the vast majority of whom live along the southeastern stretch of its 500 km coastline. Kuwait Bay, a shallow natural harbor situated at the eastern "mouth" of the country, lies...
Full-depth precast panel systems are one of the categories of accelerated bridge construction. This type of construction has many advantages in comparison with other methods of construction. Per AASHTO LRFD Specifications, the spacing of shear connectors is limited to 4 ft for concrete girders,...
Historically, rear seat positions have been considered safer than front seat positions, especially during frontal crashes. However, recent crash test results, with dummies included in their rear seats, have shown high injury measures for those dummies, exceeding the injury limits proposed by...
This research successfully applies the hot spot stress approach to steel highway bridges for fatigue evaluation of welded details subject to in-plane stress or out-of-plane distortion. The existing nominal stress approach addresses distortion only qualitatively and is unable to deal with novel...
AbstractA Critical State Two-Surface Plasticity ModelforSimulation of Flow Liquefaction and Cyclic MobilityA major part of damage to buildings and port infrastructure during seismic events is due to soil-structure interaction during ground shaking. When saturated granular soils are subjected to...
The high-rate activated sludge (HRAS) systems are shifting the energy intensive processes to low-energy and sustainable technologies for wastewater treatment. In order to recover energy-rich organic carbon from wastewater, the HRAS system is a key technology for moving towards energy neutral (or...
This dissertation addresses the development of a new approach to assess the inter-relationship among dynamic responses, and their sensitivities and robustness in crash simulation applications. Given inherent uncertainties in the laboratory data and appropriate input parameters of the model, this...
Multiple Frontal Impacts: Prevention, Prediction and ProtectionAs the sophistication and effectiveness of safety devices have increased over the years, safety engineers have begun to look beyond the crash itself. While work has continued on traditional devices such as airbags and seatbelts,...
Facilities across North America are designing plants to meet stringent limit of technology (LOT) treatment for nitrogen removal (3 mg/L total effluent nitrogen). The Blue Plains Advanced Wastewater Treatment Plant (AWTP) is one of many facilities in the Chesapeake Bay regions evaluating its...
Human behavior during an emergency evacuation is complex and difficult to predict accurately. The complexity of human behavior in these situations lies in the social interactions that have been shown to have a significant impact on decision making. Furthermore, when a hazardous situation arises...
The physics of smoke deposition from a hot layer to a wall has been studied in a hood apparatus. The hood apparatus was specifically designed to study the smoke deposition based on thermophoresis experimentally and analytically in this work. For the first time the optical density method was used...
Anaerobic digestion at mesophilic and thermophilic temperatures have been widely studied and evaluated by numerous researchers. Limited research has been conducted on anaerobic digestion in the intermediate zone of 45°C, mainly due to the notion that limited microbial activity occurs within this...
Nowadays, engineers are challenged to provide economic solutions that could be implemented within minimum schedules. Also, higher security levels are in need.One of the most time consuming tasks in a bridge project is the construction of the superstructure. Precast full-depth concrete deck panels...
Sustainable solutions for clean, affordable water are becoming increasingly important due to water scarcity problem in different parts of the world. Membrane processes can present an effective approach to address this issue. Recently developed membrane technologies such as forward osmosis (FO)...
The latest philosophy adopted by the American Association of State Highway and Transportation Officials (AASHTO), and Federal Highway Administration (FHWA) is the Load and Resistance Factor Design (LRFD) method. This philosophy accounts for the inherent uncertainties both in demand and capacity...
Two issues pertaining to the current state of pretensioning industry are investigated in this research: spacing of 0.7-in. diameter strands and effectiveness of end zone reinforcing details. Given the current economic constraints and the limitation of testing facilities, there is a great need for...
The work presented in this dissertation describes a general algorithm and its Finite Element (FE) implementation for performing concurrent multiple sub-domain simulations in linear structural dynamics. Using this approach one can solve problems in which the domain under analysis can be...
In this research development of a steering collision avoidance system was investigated. First, different control approaches to perform an evasive collision avoidance maneuver using active steering was presented. Both linear and nonlinear controllers to control the combined lateral and...
Approximately half of all numerical problems in crashworthiness analysis involve impact dynamics, and accurate contact algorithms are critical to capture the structures’ behavior. Conventional contact algorithms use the principle of preventing ‘ slave ’ nodes from penetrating ‘master’ segments....