Documenting Spatial and Temporal Variations of Subsurface Contaminates Using Tree Cores: Implications for the Design of Effective Waste Management Strategies

Proper waste management has become a worldwide humanitarian topic, because of increased awareness of potential risks posed by unsound waste disposal to human health and the environment (El-Fadel et al., 1997; Rowe et al., 1997). In remote communities in Canada’s North, here defined as the part north of the southern limit of discontinued permafrost zone, landfills and/or dumps remain the most common methods employed for the disposal of solid waste, much as they do elsewhere (Bright et al., 1995; Zagozewski et al., 2011). In northern communities, landfills or dumps have received typically household and commercial/industrial wastes or waste rocks from mineral exploration and mining activities (Bright et al., 1995; ROLES, 2014; Government of Canada, 2015). Modern engineered landfills are designed to mitigate or prevent the adverse impacts of waste on the surrounding environment. However, the generation of leachate and gas remains an inevitable consequence of existing waste disposal practices and at any future landfill sites, and risks to public health and environment may arise if sites are not well-controlled (Sawhney and Kozloski, 1984; Allen, 2001; Christensen et al., 2001; Eggen et al., 2010). Consequently, the development of innovative locality-specific strategies and methods is crucial to ensuring efficient solid waste management and environmental protectio

A framework for better understanding drinking-water quality in Happy Valley-Goose Bay, Labrador: Implications for optimization and protection of municipally supplied water

This research project was driven by the recurring complaints and concerns voiced in the media by residents living in the Valley area of the community of Happy Valley-Goose Bay, Labrador. Drinking water in this town is supplied by two water treatment plants (a municipality treatment plant and a DND treatment plant), which use raw water from two different sources (groundwater from multiple wells versus surface water from Spring Gulch brook) and use two different processes of drinking-water treatment. In fact, the drinking water supplied in the Valley area has a unique distribution arrangement. To meet demand, the Valley area is served by a blend of treated waters from a storage reservoir (Sandhill reservoir), which is fed by both water treatment plants. Most of the time, treated water from the municipal treatment plant dominates in the mixture. As water travels through the distribution system and household plumbing, specific reactions can occur either in the water itself and/or at the solid–liquid interface at the pipe walls; this is strongly influenced by the physical and chemical characteristics of the water. These reactions can introduce undesirable chemical compounds and/or favor the growth of bacteria in the drinking water, causing the deterioration of the quality of water reaching the consumer taps. In the distribution system in general, these chemical constituents and bacteria may pose potential threats to health or the water’s aesthetic qualities (smell, taste or appearance). Drinking water should be not only safe, but also palatable

Reactive power support capability of flyback microinverter with pseudo-dc link

Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 101-102).The flyback micro-inverter with a pseudo-dc link has traditionally been used for injecting only active power in to the power distribution network. In this thesis, a new approach will be proposed to control the micro-inverter to supply reactive power to the grid which is important for grid voltage support. Circuit models and mathematical analyses are developed to explain underlying issues such as harmonic distortion, and power losses, which can limit the reactive power support capability. A novel current decoupling circuit is proposed to effectively mitigate zero crossing distortion. Simulations and experimental results are provided to support the theoretical propositions.by Edwin Fonkwe Fongang.S.M

Towards resilient plug-and-play microgrids

This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2019Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 159-164).Microgrids have the potential to increase renewable energy penetration, reduce costs, and improve reliability of the electric grid. However, today's microgrids are unreliable, lack true modularity, and operate with rudimentary control systems. This thesis research makes contributions in the areas of microgrid modeling and simulation; microgrid testing and model validation; and advanced control design and tools in microgrids. These contributions are a step toward design, commissioning, and operation of resilient plug-and-play (pnp) microgrids, which will pave the way towards a more sustainable and electric energy abundant future for all."Facebook Inc. funded a portion of my PhD trajectory (2017 - 2019) by way of a Research Fellowship"by Edwin Fonkwe Fongang.Ph. D.Ph.D. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Scienc

Production and characterization of proteins from mechanically deboned turkey residue

The main objectives of this investigation were to determine appropriate methods for recovering proteins from mechanically deboned turkey residue (MDTR), investigating their characteristics and functionality, and recommending their potential uses in human nutrition. The first protein extracts were recovered by alkali extraction. The protein solution was either concentrated by ultrafiltration and dried, or precipitated with acid and dried. The protein yields for the latter methods were 22% and 15%, respectively. These proteins were yellow in color and had BET monolayer values of 3.8 and 4.5 g water/g, respectively. They had poor functional properties, especially their solubility in water, but they had good nutritional qualities (chemical score (CS) = 0.94; essential amino acid index (EAAI) = 1.29). Thus they can be used potentially in comminuted poultry products as protein substitutes. Three grades of gelatin were also produced from the MDTR following the alkali extraction process. The process produced 31 g proteins/g MDTR. All the gelatins had high mineral and protein contents and high intrinsic viscosities. They were very soluble in hot water. They formed gels but their gel strengths were lower than that of a commercial gelatin sample. They contained mainly high molecular weight proteins and their molecular weight distribution was similar to that of a commercial gelatin sample. They had poor functional properties and nutritional quality (CS = 0.34, 0.31 and 0.32). They can be used in products such as sauce thickeners and in the manufacture of edible films, based on their good gelling properties. The third protein extract produced from the MDTR was a protein hydrolysate using papain. The hydrolysate was highly soluble in water at room temperature over a wide pH range ($\u3e$90%), was comprised mainly of amino acids and short peptides, and was rich in the minerals calcium, magnesium, phosphorous, zinc and iron. It had a high buffering capacity, but a low nutritional quality (CS = 0.54; EAAI = 0.81). However, it can be thermally processed and used as a high protein diet supplement, or in the manufacture of sports, medical, hypoallergenic or other similar diets due to their high solubility and high content of amino acid and short peptides