Water distribution system (WDS) is very critical to human health and societal welfare. Maintaining the quality of the water so that potable water gets distributed to consumers has always been a challenge in the water industry. Deterioration of water quality can happen either accidentally or deliberately and the widespread geography of the water system makes it even more vulnerable to contamination. In this respect, researchers and utilities have some response action to flush out the contaminants when they are detected. But not all networks have reliable sensors to detect the contamination and lack of guidelines for sensor deployment has made the situation even more serious. Given this context, framework for decision-making in the case of WDN against contamination is a much-needed approach. Understanding the capability of the water system to handle the contamination event could provide ample insight on how to better protect the system and how to handle if the contamination does enter the system. In this regard, this study explores the concept of resilience to define the system performance when a disruption occurs, which in this case is the intrusion of contaminants. Resilience of a system can be viewed from different perspectives, each highlighting different aspect of the system. With this insight, the objective of this research is to characterize the resilience of the water system against contamination for multiple aspects of performance or functionalities and use that concept to further elucidate the decision-making process. Hydraulic and quality simulation to emulate the contamination intrusion in WDN is performed by using EPANET-MATLAB Toolkit which has the needed package for both EPANET and EPANET-MSX. EPANET-MSX is widely used for simulating multiple intrusions in the system. The result from the MATLAB simulation gives the quality at each node which is then used to draw the performance time-series curve. Resilience is then computed for each of the performance metrics using the area under the curve method. This study makes a comparison study for multi-dimensional resilience and describes in detail the need of considering the attributes of resilience which are resistance, loss rate, recovery rate, failure duration, and recovery ability. To perceive the concept of resilience with respect to the failure scenarios, a sensitivity analysis was performed for four failure contexts namely, intrusion time, intrusion duration, intruded contaminated mass, and the number of intrusion nodes. Furthermore, a system measure is defined to aggregate different individual resilience to overcome the challenge of multi-objective decision-making. Application of both integrated and multi-dimensional resilience was conducted for optimal sensor placement in the network to maximize the resilience of the whole system. The goal of this thesis is to introduce the multi-dimensional resilience concept as a tool for decision-making based on multiple aspects of system performance by characterizing the WDS resilience and water quality sensor optimization based on different aspects of system functionality under contaminant intrusion events.

An important consideration for spacecraft material selection is the space environment that the spacecraft will be operating in. Two features of the space environment that drive material selection are material outgassing and the presence of atomic oxygen in low Earth orbit (LEO). Materials that are considered for use in space are tested to be able to understand how they’ll outgas on orbit and how they’ll respond to interactions with atomic oxygen. However, testing to understand how atomic oxygen interaction with a material will affect how the material will outgas is rare and not standardized. This thesis used a vacuum chamber intended to determine the outgassing properties of materials using ASTM E595 and another vacuum chamber intended to determine how materials are affected by atomic oxygen using ASTM E2089 to determine how atomic oxygen affects outgassing of silicones, which are of interest as atomic oxygen can alter the chemical composition of the surface of silicones. CV-2500, CV2-2289- 1, and SCV2-2590, three silicone elastomers that are products of NuSil Technology LLC, were tested. Significant trends in atomic oxygen reducing the amount of matter outgassed from these three materials were observed. This can be explained by the conversion of the surface of silicone to silica, which was confirmed using Fourier Transform Infrared (FTIR) spectroscopy. Retesting of these three materials in a chamber designed for ASTM E595 with a temperature measurement system capable of adhering to ASTM E595 to confirm the results of this thesis with more confidence in uniform temperature exposure is recommended.

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Eutrophication, caused by phosphate, can be detrimental both for the aquatic environment and human health. This research aims to provide deep knowledge about the adsorption properties of low-cost Fe/Mg layered double hydroxide modified biochar (LDHBC) for removal of phosphate from aqueous solution. Firstly, Fe/Mg layered double hydroxide (LDH) was synthesized by mixing FeCl3 and MgCl2. 6H2O salts in water, followed by NaOH treatment (coprecipitation method). For LDHBC, FeCl3, and MgCl2. 6H2O salts were dissolved in water, and Douglas fir biochar was added to the salts mixture to make a slurry, followed by NaOH treatment. The surface chemistry and elemental composition of both adsorbents and phosphate-laden adsorbents were characterized using Elemental analysis, BET, PZC, TGA, DSC, XRD, SEM, and TEM. Adsorption ability of LDH and LDHBC was studied by pH effects, kinetics, and the highest capacity for the analyte.

Petroleum spills cost large sums of money to remediate, which has resulted in the use of more in-situ technologies, including chemical oxidation, as cost effective alternatives to traditional methods of remediation. There are numerous case studies documenting the success of hydrogen peroxide as an in-situ oxidizer in that regulated BTEX concentrations were lowered below target cleanup levels. Little information is available; however, regarding the behavior of petroleum hydrocarbons post injection of hydrogen peroxide or what chemical derivatives may be produced as a result of the oxidation process. Laboratory protocols have been employed to yield data regarding the behavior of BTEX specifically, and all volatile gasoline constituents in general, over a period of time post injection of hydrogen peroxide. The results of the data indicate variations in petroleum compound behavior are predicated on the concentration of hydrogen peroxide, the degree of contamination, and the presence of a soil matrix.

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