Engineering Commons^™

Biocrude Production From Lignin In Hydrothermal Medium: Effect Of Rapid Heating And Short Residence Time, Kyoko Hirayama

Civil & Environmental Engineering Theses & Dissertations

This study aims to address knowledge gaps in the production of valuable products from waste streams generated during lignocellulosic biofuel production. The primary objective is to develop a process that converts lignin, a byproduct of bioethanol refineries, into a sustainable biolubricant.

The first chapter examines recent advancements in synthesizing biolubricants and investigates their scalability. It explores innovative materials, catalysts, chemical modification approaches, and additives that have emerged in the field. A particular hurdle is the oxidative stability of biolubricants derived from plant oils, which are prone to autooxidation due to their C=C bonds. To overcome this, the study aims to …

Evaluating Direct Filtration As An Alternative To Conventional Carbon-Based Advanced Treatment For Indirect Potable Reuse, Savannah M. Flemmer

Civil & Environmental Engineering Theses & Dissertations

Hampton Roads Sanitation District (HRSD) is recharging purified wastewater into the Potomac Aquifer via the Sustainable Water Initiative for Tomorrow (SWIFT) project. Conventional SWIFT treatment applies coagulation, flocculation, sedimentation, ozonation, biofiltration, granular activated carbon (GAC) adsorption, and ultraviolet disinfection to secondary effluent to produce water that meets drinking water standards for managed aquifer recharge. HRSD is considering implementing direct filtration as an alternative to conventional treatment for two additional SWIFT facilities. Direct filtration presents an opportunity for significant cost savings by eliminating sedimentation, shortening flocculation detention time, and reducing coagulant usage. Without upstream removal of solids and organics, however, biofilters …

Optimal Domain-Partitioning Algorithm For Real-Life Transportation Networks And Finite Element Meshes, Jimesh Bhagatji, Sharanabasaweshwara Asundi, Eric Thompson, Duc T. Nguyen

Civil & Environmental Engineering Faculty Publications

For large-scale engineering problems, it has been generally accepted that domain-partitioning algorithms are highly desirable for general-purpose finite element analysis (FEA). This paper presents a heuristic numerical algorithm that can efficiently partition any transportation network (or any finite element mesh) into a specified number of subdomains (usually depending on the number of parallel processors available on a computer), which will result in “minimising the total number of system BOUNDARY nodes” (as a primary criterion) and achieve “balancing work loads” amongst the subdomains (as a secondary criterion). The proposed seven-step heuristic algorithm (with enhancement features) is based on engineering common sense …

Understanding And Assessing Demographic (In)Equity Resulting From Extreme Heat Exposure Due To Lack Of Tree Canopies In Norfolk, Va Using Agent-Based Modeling, Virginia Zamponi, Kevin O'Brien, Erik Jensen, Brandon Feldhaus, Russell Moore, Christopher J. Lynch, Ross Gore

VMASC Publications

Prolonged exposure to extreme heat can result in illness and death. In urban areas of dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat, extreme heat conditions can arise regularly and create harmful environmental exposures for residents daily during certain parts of the year. Tree canopies provide shade and help to cool the environment, making mature trees with large canopies a simple and effective way to reduce urban heat. We develop a demographically representative 1 (agent): 1 (person) agent-based model to understand the extent to which different demographics of residents in Norfolk, VA are equitably shaded …

An Updated Analytical Method For Predicting The Bracing Behavior Of Z-Purlin Supported Standing Seam Diaphragm Systems, Michael W. Seek

Engineering Technology Faculty Publications

Roof systems utilizing Z-purlins as a secondary member supporting a standing seam panel system are used extensively by the metal building industry. The Z-purlins rely on the diaphragm action in the standing seam panel system to provide lateral support and transfer forces to anchorages. The behavior of the standing seam system is highly nonlinear making prediction of the interaction between the Z-purlin and the standing seam system difficult. To better understand the behavior of the interaction between the purlins and the panel system, a series of non-linear shell finite element models were developed based on the test results of simple …

A User-Centered Mapping Design For Geomorphological Hazard Thematic Map, Su-Min Shen, Yin-Hsuen Chen, Chia-Ming Lo, Mu-Ti Yu, Si-Chin Lin, Sendo Wang, Chih-Hsin Chang, Sheng-Chi Lin

University Administration Publications

Numerous studies have concentrated on developing user-centered designs for hazard zone maps but rarely for hazard-oriented geomorphological maps, named as Geomorphological Hazard Thematic Maps (GHTMs) in this study, which provide more detailed information about natural hazards. This study developed a user-centered mapping design for GHTMs for nonexperts in geomorphology. We invited civil engineers and high school educators to evaluate a sample GHTM's design in group and focus group panel interviews. The civil engineers preferred maps with more geomorphological features, whereas the educators preferred simple designs. Both groups indicated that the inclusion of essential facilities and road networks is essential. The …

Higher-Order Effects In Biaxial Flexure Of Gfrp I-Section Beams, Zia Razzaq, Faridoon Z. Razzaq

Civil & Environmental Engineering Faculty Publications

A theoretical study of Glass Fiber Reinforced Polymer (GFRP) beams subjected to biaxial bending moments is presented with a focus on the influence of higher-order effects on maximum normal stresses. It is shown that the biaxial bending type of loading causes a dramatic increase in the maximum normal stress for a GFRP beam when induced torsional effects are included. The study demonstrates that the traditional first-order theory can grossly underestimate the maximum normal stress in a GFRP beam. Based on the numerical results presented using a higher-order theory which also accounts for induced warping normal stresses, the maximum normal stress …

Rainwater Catchment System In Public Sector Housing, Araceli Peña, Muhammad Yanzar Sarin

2023 REYES Proceedings

Water is a universal right for all living beings on the planet, but today it has become a commercial good. It costs significantly to extract water from increasingly distant storage sources. For these reasons and many more the fight for water has become increasingly intense. Precisely, an alternative to avoid more dam construction is the implementation of public politic with actions focused on the integral solution of water, that is to say, that it be distributed fairly and equitably to all users, avoiding more concessions to great industries like as soft drinks and breweries, which are the main consumers and …

Elastoplastic Quasi-Static And Impact Load Response Of Steel Structure Sub-Assemblage With Cfrp Strips, Ali Al Aloosi, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

Presented in this paper is the outcome of an experimental investigation of the elastoplastic quasi-static and impact load response of a steel sub-assemblage constructed using a pair of hollow square section members with or without Carbon Fiber Reinforced Polymer (CFRP) strips. The sub-assemblage consists of a long structural member welded to a short member, thus representing a typical combination of a column and a beam on the face of a multi-story steel building frame. The column is subjected to a lateral quasi-static or impact load. Tests are conducted on four separate steel sub-assemblages. The first two tests are conducted with …

Effects Of Salix Psammophila On Groundwater Recharge In A Semiarid Area Of North China, Lizhu Hou, Jingdong Gao, Bill X. Hu, Xixi Wang

Civil & Environmental Engineering Faculty Publications

Study region: The semiarid Mu Us Sandy Land (MUSL) was selected for this study. It is in the farming-pastoral ecotone of north China and functions as an eco-environmental barrier.

Study focus: Afforestation can mitigate desertification and soil erosion by improving hydrologic condition, which is particularly true for semiarid and arid regions. However, little is known about the quantitative response of hydrologic improvement to afforestation level that can be measured by leaf area index (LAI). The objective was to setup and use a physically-based model to quantitatively assess the dynamics of water fluxes from Salix psammophila afforestation in the MUSL.

New …

A Simulation Way To Investigate The Reason For Congestion In Urban——A Case Study In Hohhot China, Junqing Wang, Hong Yang, Yuan Zhu, Qingwen Pu, Shunlai Cui

College of Engineering & Technology (Batten) Posters

In the case of high density traffic flow, traditional traffic data statistical analysis methods, which not only have certain errors and lead to inaccurate data, but also have many limitations such as labor consumption, can no longer meet the demand for traffic analysis. Drones for traffic data, based on an aerial bird's-eye view, no offset, and error-free complete statistics of urban road shooting section of all data, while greatly reducing cost consumption. A multi-dimensional simulation model is established for the UAV data to the Hohhot central urban area's road simulation platform. This project will test and explore multidimensional data in …

Investigating The Impacts Of Connected Vehicles On Driving Aggressiveness And Situational Awareness In Highway Crash Scenarios: A Driving Simulator Study, Abdalziz Alruwaili

College of Engineering & Technology (Batten) Posters

Psychological factors such as aggressiveness and situational awareness can impact driving performance. Connected vehicles (CV), equipped with advanced sensors and able to communicate safety messages to drivers, have the potential to influence driving performance by altering drivers’ aggressiveness and situational awareness. This paper aims to investigate the impacts of the CVs on driving aggressiveness and situational awareness in highway crash scenarios where a primary crash has already occurred, and a second crash may occur as a result. To achieve this goal, a driving simulator experiment was conducted, and questionnaires focused on driving aggressiveness and CV effectiveness were distributed. Structural equation …

Production Of Lithium Carbonate From Geothermal Brine By Selective Extraction Of Lithium Using A Novel Ion Sieve Method, Ujjwal Pokharel, Sandeep Kumar

College of Engineering & Technology (Batten) Posters

The project implements a novel approach to extract lithium from a geothermal brine with minimal water loss. Production of high-capacity lithium-ion (Li-ion) batteries for electric vehicles (EV) is believed to be the way to reduce dependence on fossil-fuel based vehicles. Currently, most of the lithium in the world comes from the mining of lithium or the evaporative/concentration of the brine. Mining is not environmentally friendly, and the evaporative process takes 12 months for the completion of the extraction process and results in a large amount of water loss which can lead to scarcity of water. The brines constitute 82% of …

Numerical Study Of Sediment Suspension Affected By Rigid Cylinders Under Unidirectional And Combined Wave-Current Flows, Sha Lou, Xiaolan Chen, Shengyu Zhou, Gangfeng Ma, Shuguang Liu, Larisa Dorzhievna Radnaeva, Elena Nikitina, Irina Viktorovna Fedorova

Civil & Environmental Engineering Faculty Publications

Sediment transport modeling for flows with cylinders is very challenging owing to the complicated flow–cylinder–sediment interactions, especially under the combined wave-current flows. In this paper, an improved formulation for incipient sediment suspension considering the effect of cylinder density (i.e., solid volume fraction) is employed to simulate the bottom sediment flux in the flow with cylinders. The proposed model is calibrated and validated using laboratory measurements under unidirectional and combined wave-current flows in previous studies. It is proved that the effects of cylinders on sediment suspension can be accounted for through a modified critical Shields number, and the proposed model is …

Automating Intersection Marking Data Collection And Condition Assessment At Scale With An Artificial Intelligence-Powered System, Kun Xie, Huiming Sun, Xiaomeng Dong, Hong Yang, Hongkai Yu

Civil & Environmental Engineering Faculty Publications

Intersection markings play a vital role in providing road users with guidance and information. The conditions of intersection markings will be gradually degrading due to vehicular traffic, rain, and/or snowplowing. Degraded markings can confuse drivers, leading to increased risk of traffic crashes. Timely obtaining high-quality information of intersection markings lays a foundation for making informed decisions in safety management and maintenance prioritization. However, current labor-intensive and high-cost data collection practices make it very challenging to gather intersection data on a large scale. This paper develops an automated system to intelligently detect intersection markings and to assess their degradation conditions with …

Elevation-Distributed Multistage Reverse Osmosis Desalination With Seawater Pumped Storage, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

A seawater reverse osmosis (RO) plant layout based on multistage RO with stages located at different elevations above sea level is described. The plant uses the weight of a seawater column from pumped storage as head pressure for RO (gravity-driven multistage RO) or to supplement high-pressure pumps used in RO (gravity-assisted multistage RO). The use of gravitational force reduces the specific energy for RO compared to using high-pressure pumps. By locating the RO stages at different elevations based on demand sites, the total specific energy consumption for RO and permeate transport to different elevations above sea level is reduced from …

Are Ride-Hailing Services Safer Than Taxis? A Multivariate Spatial Approach With Accomodation Of Exposure Uncertainty, Guocong Zhai, Kun Xie, Hong Yang, Di Yang

Civil & Environmental Engineering Faculty Publications

Despite many research efforts on ride-hailing services and taxis, limited studies have compared the safety performance of the two modes. A major challenge is the need for reliable mode-specific exposure data to model their safety outcomes. Moreover, crash frequencies of the two modes by injury severities tend to be spatially and inherently correlated. To fully address these issues, this study proposes a novel multivariate conditional autoregressive model considering measurement errors in mode-specific exposures (MVCARME). More specially, a classical measurement error structure is used to accommodate the uncertainty of mode-specific exposures estimated, and a multivariate spatial specification is adopted to capture …

Modeling The Production Of Microalgal Biomass In Large Water Resource Recovery Facilities And Its Processing Into Various Commodity Bioproducts, James Pierson, Gopi Raju Makkena, Sandeep Kumar, Vinod Kumar, Vivekanand Vivekanand, Hasan Husain, Muhammad Ayser, Venkatesh Balan

Civil & Environmental Engineering Faculty Publications

Algae are capable of sequestering nutrients such as nitrates and phosphates from wastewater in the presence of sunlight and carbon dioxide (CO₂) to build up their body mass and help combat climate change. In the current study, we carried out different case studies to estimate the volume of algal biomass that could be produced annually using the rotating algal biofilm (RAB) method in three large-scale water resource recovery facilities (WRRFs) in Texas: Fort Worth, Dallas, and Houston. We calculated the total amount of lipids, carbohydrates, and proteins that could be fractionated from the algal biomass while using the …

Analysis Of Traffic Conflicts With Right Turning Vehicles At Unsignalized Intersections In Suburban Areas, Abbas Sheykhfard, Farshidreza Haghighi, Sarah Bakhtiari, Sara Moridpour, Kun Xie, Grigorios Fountas

Civil & Environmental Engineering Faculty Publications

Right-turn collisions at intersections are one of the most dominant crash types in suburban areas, especially at unsignalized intersections. There is, however, a lack of comprehensive research on the speed patterns of vehicles during right-turn manoeuvres and their impact on crashes. To provide an in-depth investigation of the factors determining the safety of right-turn manoeuvres, driving behaviour data were collected through an instrumented vehicle study. Using this data, binary logistic regression models were developed to identify the factors affecting the probability of Vehicle-Vehicle (V-V) and Vehicle-Pedestrian (V-P) conflicts at six suburban intersections in Babol, Iran, during right-turn stage manoeuvres. In …

Reduced Metal Nanocatalysts For Selective Electrochemical Hydrogenation Of Biomass-Derived 5-(Hydroxymethyl)Furfural To 2, 5-Bis(Hydroxymethyl)Furan In Ambient Conditions, Baleeswaraiah Muchharla, Moumita Dikshit, Ujjwal Pokharel, Ravindranath Garimella, Adetayo Adedeji, Kapil Kumar, Wei Cao, Hani Elsayed-Ali, Kishor Kumar Sadasivuni, Naif Abdullah Al-Dhabi, Sandeep Kumar, Bijandra Kumar

Chemistry & Biochemistry Faculty Publications

Selective electrochemical hydrogenation (ECH) of biomass-derived unsaturated organic molecules has enormous potential for sustainable chemical production. However, an efficient catalyst is essential to perform an ECH reaction consisting of superior product selectivity and a higher conversion rate. Here, we examined the ECH performance of reduced metal nanostructures i.e., reduced Ag (rAg) and reduced copper (rCu) prepared via electrochemical or thermal oxidation and electrochemical reduction process, respectively. Surface morphological analysis suggests formation of nanocoral and entangled nanowire structure formation for rAg and rCu catalysts. rCu exhibits slight enhancement in ECH reaction performance in comparison to the pristine Cu. However, the rAg …