Inferential/Parametric Forecasting of Subsurface Oil Trajectory Integrating Limited Reconnaissance Data with Flow Field Information for Emergency Response
Mary Jacketti, Chao Ji, Dr. James D. Englehardt Department of Civil, Architectural, & Environmental Engineering Following an oil spill, oil often sinks below the water surface, either to the bottom or to a neutrally-buoyant layer in the water column. In such cases the sunken or submerged oil is very difficult to locate due to limited visibility, lack of information on bottom currents, and the effects of changes in temperature (oil density), salinity, weathering, and wave-induced sediment entrainment that cause re-suspension and re-deposition of the oil mass. An initial version of the model SOSim (Sunken Oil Simulator) was developed by our research group at UM as an alternative to existing oil spill models that track oil based on pre-existing flow-field data on water currents. We are currently partnering with SINTEF Ocean, Trondheim, Norway, to expand SOSim, specifically for use in supporting emergency response efforts to search for subsurface oil. The model uses predictive Bayesian statistical techniques and limited available field reconnaissance data on oil concentrations as a function of location in the water body to assess the location of the entire oil mass and project its movement in time. A Lagrangian modeling technique is coupled with Bayesian inference to assess unconditional probabilities, equivalent to relative concentrations of oil on the bottom of a water body or in the water column. The new model will be able to handle continuous spills for both sunken and submerged oil and will incorporate prior information including bathymetry and output from other fate and transport models. The model is being written in Python and input information can be entered by the user through the Graphical User Interface (GUI). With spills of heavy oils becoming more prevalent, we expect that SOSim will become an important tool for emergency response efforts.
pH shifting and nutrient recovery for net-zero water treatment
Mahamalage Kusumitha Perera, James D. Englehardt Department of Civil, Architectural, & Environmental Engineering The current trend towards indirect potable water reuse is driving regulations for extremely low nutrient concentrations in treated wastewater, and the reverse osmosis and ion exchange processes required to meet these environmentally-responsible levels are prohibitively expensive. In addition phosphorus (P) is a non-renewable resource, production of nitrogen (N) fertilizer is energy intensive, and discharge of these nutrients in treated wastewater causes eutrophication. As a solution, we have developed a new chemical-free electrochemical pH modulation process to recover nitrogen (N) and phosphorus (P) simultaneously from conventional and mineral spiked [to mimic net-zero water (NZW)] actual settled sewage, in a form suitable for storage and use as fertilizer, in a process that may allow affordable compliance with indirect potable reuse regulations. Nutrients are recovered by modulating the pH with a divided electrochemical cell which uses multi-valent cation exchange membrane (MCEM). First, the influent pH is dropped to remove carbonates, then raised to recover nutrients, and finally the effluent is neutralized before discharge. pH modulation performance was evaluated with three different MCEMs and CMI-7000 produced best results. Phosphates were precipitated as calcium phosphate at high pH, and the recovered precipitates were analyzed using scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDS) and X-ray powder diffraction (XRD) techniques to characterize the composition as principally amorphous calcium phosphate, with Ca:P ratio of 2:1. Nitrogen is recovered by stripping and absorbing into acid to produce an ammonium sulfate solution. The total organic carbon test indicated that the recovered ammonium sulfate product contained only 2.74% impurities based on the NH3 content. Currently, a flow-through reactor is being developed to simultaneously recover both N & P, and so far, achieved average recovery of 68 and 83% respectively.
Nanohybrids - Design and characterization, toxicity, and environmental applications
Soyoung Baek, Dr Sung Hee Joo Department of Civil, Architectural, & Environmental Engineering Despite the increasing number of applications of nanomaterials in multidisciplinary fields, few studies have investigated the toxicity and antibacterial mechanisms of nanohybrids (NHs). Such studies could offer an innovative solution for emerging contaminants of concern (e.g., multi-drug resistant bacteria) present in water. In this study, we focused on metal oxides-conjugated graphene oxides versus carbon nanotubes (i.e. ZnO-GO, TiO2-GO, ZnO-CNT, TiO2-CNT) to identify antibacterial effects, associated mechanisms of the model NHs, and characterization of the NHs. The synthesized NHs through hydrothermal process were characterized using a microscopic technique before and after exposure to E. coli. Results show significant aggregation and cell damage surrounded by NHs, especially after exposure of E. coli to GO-based NHs, due to increasing dispersibility and larger surface areas. To explore antibacterial mechanisms, cell growth inhibition was measured as well as the generation of reactive oxygen species (ROS) in the presence and absence of N-acetyl-L-cysteine (NAC) – a scavenger of ROS. Interestingly, the antibacterial effects and ROS generation were most significant from ZnO-GO, followed by ZnO-CNT, TiO2- GO, and TiO2-CNT. While our results suggest the physicochemical properties and the generation of ROS are two primary mechanisms, other mechanisms from steric effects and from the release of metal ions, especially from ZnO-GO and ZnO-CNT may occur. Ongoing research is being carried out to further examine antibacterial effects from released metal ions. This study suggests significant implications in terms of applications of NHs for the treatment of difficult-to-treat emerging contaminants, such as multi-drug resistant bacteria detected in water. Future research is directed toward applications of NHs for degradation of emerging contaminants of concern in water.
Cellular Morphogenesis of tensegrity structures
Omar Aloui, Landolf Rhode-Barbarigos Department of Civil, Architectural, & Environmental Engineering The topology and form finding of tensegrity structures have been studied extensively since the introduction of the tensegrity concept. However, most of these studies address topology and form separately, where the former represented a research focus of rigidity theory and graph theory, while the latter attracted the attention of structural engineers. In this work, a biomimetic approach for the combined topology and form finding of spatial tensegrity systems is introduced. Tensegrity cells, elementary infinitesimally rigid self-stressed structures that have been proven to compose any tensegrity, are used to generate more complex tensegrity structures through the morphogenesis mechanisms of adhesion and fusion. A methodology for constructing a basis to describe the self-stress space is also provided. Through the definition of self-stress, the cellular morphogenesis method can integrate design considerations, such as a desired shape or number of nodes and members, providing great flexibility and control over the tensegrity structure generated.
Degradation of Naled in Natural Waters Collected from Areas Impacted by Aerial Spray Activities
Francisco Alberdi1, Amanda Sanabria2, Nakiya Clausell1, Athena Jones1, David Cohen3, Helena Solo-Gabriele1, Matthew Roca1, Elsayed Zahran4 1 Department of Civil, Architectural, and Environmental Engineering 2 Department of Biomedical Engineering 3 Department of Electrical and Computer Engineering 4 Department of Chemistry Naled is an organophosphate pesticide frequently applied aerially to control mosquito-borne disease transmission and nuisance mosquito bite rates. Since the first continental U.S. Zika outbreak in 2016, the wide-spread application of Naled has been questioned because of the danger presented to non-target organisms (e.g., pollinators), the persistence of the pesticide in the environment, and the ultimate impact on human health – all of which have not been fully determined. The objective of this study was to evaluate the persistence of naled in natural waters exposed to aerial sprays. Freshwater and marine water samples were analyzed in the laboratory to evaluate the influence of ultraviolet light (UV), naturally occurring nucleophiles, and hydrolysis on the degradation rate of naled in water. Water samples were also collected in the field to document levels observed immediately after an aerial spray. Naled was found to degrade into dichlorvos – an organophosphate pesticide banned for use as an aerial spray – in all laboratory experiments. The half-life of naled in natural waters exposed to UV was determined to be about ten minutes, versus a half-life of about six hours for naled not exposed to UV. Experiments with deionized water resulted in prolonged persistence of naled (half-life of more than 1 week), demonstrating that naturally occurring nucleophiles promote degradation. Water samples collected in the field suggest that naled levels are detectable (13 µg/L in freshwater and 19 µg/L in marine water) immediately after aerial sprays. Further research is needed to utilize these results to assess human health and ecosystem impacts.
Can a pozzolanic test be used to predict degree of reaction of supplementary cementitious materials?
Sivakumar Ramanathan, Michael Croly, Prannoy Suraneni Department of Civil, Architectural, & Environmental Engineering Supplementary cementitious materials (SCMs) are used to replace ordinary portland cement (OPC) in concrete for various reasons, the most important being improved durability characteristics and reduced CO2 emissions, thereby leading to sustainability. The increased durability is in part attributed to a reaction between the SCMs and the hydration products of the cement, known as the pozzolanic reaction. One challenge associated with the use of SCMs is that the degree of this reaction, which determines the benefits provided by the SCM, is typically hard to determine. A recently developed pozzolanic test, which employs isothermal calorimetry and thermogravimetric analysis has been used to classify SCMs as “inert”, “hydraulic”, and “pozzolanic”. The objective of this study is to evaluate whether such a pozzolanic test can be used to predict the degree of reaction of SCMs when used in cement. Four commonly used SCMs, namely, fly ash, ground granulated blast furnace slag, silica fume, and metakaolin are tested and classified using the pozzolanic test. To assess the degree of reaction of these materials in cementitious pastes, the heat release and the calcium hydroxide consumption are calculated. Two parameters, namely, heat ratio and calcium hydroxide ratio, are been proposed as indicators for the degree of reaction of the SCMs. Comparison with literature suggests that these tests may be used to obtain SCM degree of reaction, although further testing is needed to confirm this hypothesis.
A Bio-Inspired Approach for Sustainable Concrete Infrastructure
Katelyn Kosar and Ali Ghahremaninezhad Department of Civil, Architectural, & Environmental Engineering Nature is inspiring biologists, chemists, and engineers to research together and create bioinspired materials that could advance various fields, including civil engineering. Bioinspired materials are materials found in nature that can be used, modified, or modeled for a man-made application. These new materials can already be seen in industry in designs and materials. To bring bioinspired materials to civil engineering, proteins are being considered as a baseline to creating a new admixture. This research considers three common proteins (albumin, hemoglobin, and lysozyme), their morphology in an alkaline environment and effects on the mechanical properties of cement. The foaming properties of proteins in cement pore solution were investigated to determine foam capacity and stability changes. Common mechanical testing was done on cement samples with protein concentrations of 0%, 0.05%, 0.25%, 0.5%, and 1.0% to determine how the cement is affected in low and high concentrations. Data is currently being analyzed to identify the structural and chemical properties of the proteins and relate results to changes seen in cement so that someday, a synthetic admixture based on these natural proteins can be designed.
Use of Hydrogels to Improve Sustainability in Concrete
Babak Vafaei, Ali Ghahremaninezhad Department of Civil, Architectural, & Environmental Engineering The use of alkali-activated slags (AAS)s has been investigated as an alternative to binders produced from ordinary Portland cement (OPC) due to advantageous properties such as high compressive strength, high durability, high resistance to chemical attack, and low hydration heat. Despite its advantages, high autogenous shrinkage of AAS, which is the main drawback of AAS and is larger than that of Portland cement, represent the most serious limitation for the dissemination of its use. In the internal curing method, in order to maintain a high relative humidity inside the material, an internal water reservoir with a high water absorption capacity is used. This internal curing agent releases water into its surrounding region in the cementitious microstructure. The shrinkage and cracking risk can be significantly mitigated by using the superabsorbent polymer (SAP)-based internal curing method. The main objective of this research is to focus on studying the influence of addition of SAP on autogenous shrinkage, hydration, strength and macrostructure of AAS.
Energy-aware and conflict-free UGV routing in an autonomous warehouse
Mona Issabakhsh, Seokgi Lee Department of Industrial Engineering High labor manufacturing costs has brought a significant amount of attention to smart robotic warehouse management systems, where tasks are done by autonomous unmanned ground vehicles (UGVs). UGVs are used to enhance the effectiveness and efficiency of the warehouses procedure in many big companies such as Amazon, DHL and Alibaba. UGVs lift racks to workstations instead of dragging. They can pass under the racks, which maximizes utilization of space, labor and resources. UGVs do not need bright lights and comfortable air conditioning to perform operations, such that the logistic service providers can save electricity cost and protect the environment. Finding the optimal number of vehicles required, vehicle scheduling and routing, traffic and load transfer and system management, deadlock resolution and idle-vehicle positioning are some of the prominent elements of designing an UGV system. Automatic transportation system has many advantages compared to the traditional material handling system, however; if UGVs are not controlled along the routes in such a system, the production system breakdown due to UGV collisions is possible. Therefore, the Conflict-Free Routing Problem (CFRP) of UGVs is considered. UGVs use battery as the source of energy, mostly. Battery management therefore plays an important role to improve the performance of a firm using battery driven vehicles by running an efficient UGV system. Also, energy consumption management plays a prominent role in manufacturing cost reduction. The goal of this initial research, therefore, would be to develop a mathematical UGV routing model with battery recharge schedules, which prevents from multiple UGV collisions, while minimizing costs of routing and energy consumption. This work is partially supported by research grant of Toyota Material Handling North America (TMHNA).
Resilient Transportation Network Design for A Major Air Carrier Against Hurricane Disruptions
Yusuf Seçerdin Department of Industrial Engineering In this study, we consider the routing and scheduling of air fleet of a major express cargo service provider in the Caribbean. The problem is formulated as a service network design problem (SNDP) on a hierarchical hub-andspoke network. The transportation of an express package as well as feeder network of the carrier are shown in Figure 1. This study is composed of two main parts, service network design under normal conditions and resilient service network design under the risk of disruptions caused by hurricanes.
Enhancing coastal resilience through advanced physical and numerical modeling
Mohammad Ghiasian, Landolf Rhode-Barbarigos Department of Civil, Architectural, & Environmental Engineering Extreme winds and flooding have always been an issue of paramount importance for coastal regions, such as Florida and the Gulf. However, the recent impacts of hurricanes Harvey, Irma, and Maria, have highlighted the urgent need to make the built environment and infrastructure less prone to damages from windstorms and coastal flooding events. Improving the performance of structures under hurricane winds, waves and storm-surge requires a better knowledge of their combined action. Therefore, physical modeling is conducted in the SUrge STructure Atmosphere INteraction (SUSTAIN) Facility at Rosenstiel School of Marine and Atmospheric Science (RSMAS) which enables the controlled testing of wind, wave and surge dissipation under extreme (winds up to Saffir-Simpson Hurricane category 5) conditions and thus the experimental definition of the combined wind/wave load on coastal structures. Infrastructure networks, such as the electric power network and the transportation network, can be mathematically modeled using graphs: sets of vertices and edges. Through the study of self-stressed graphs (known also as tensegrity frameworks) and their behavior under the removal of vertices or edges, strategies on increasing the damage tolerance of infrastructure networks are sought.
Hybrid Energy Harvesting can provide Soldiers reliable backup energy and allow sustained operations
Andrea M. Peters Department of Mechanical Engineering Energy harvesting has been around since the dawn of time as civilizations sought to produce power through mechanical, pyrotechnics, and electrical means. Today energy harvesting is used in all facets of society and innovators and educators seek to exploit this resource in hopes of finding sustainable energy sources. The military is no different as the world continues to become more and more dangerous and missions become more and more unpredictable; there must be a way to harness power in all forms. The 22nd century Soldier must have the means to operate longer without the frequent need of resupply. This can only be done through harvesting. I believe the answer to this energy need is hybrid energy harvesting where not just one form of harvesting is exploited, but multiple forms are exploited and linked to produce energy for later use or immediate sustained energy should the need arise. At this point, these systems do not talk, but I believe they should and will communicate to produce sustained power for the military and for the greater population as recourses continue to deplete.