Recovery of Polystyrene in Lost Foam  This technology emerged from a research program initiated to assist the metal casting industry in prevention of polymer waste disposal, and to promote engineering solutions leading to reuse of the polymer. Our research strategy was based the principles of modern mineral processing technology to polymer recovery. The program includes particulate characterization, examination of surface-interfacial properties of the pattern components, development of an analytical technique for contaminant concentration measurements, shredding and size reduction, and selective separation testing based on component density. Our results indicate that as high as 98% of the polystyrene can be recovered, while the level of coating contaminants did not exceed 5 wt% in the final product, after using the developed technology. |
Purification of PET from PVC A technology involving treatment of PET and PVC particles with alkaline solutions followed by froth flotation of PVC with noinonc surfactants has been developed. In development research, this technology yielded 95-100% recovery of PET and PVC in separate products from a variety of PVC/PET mixtures. |
Surface Chemistry Features of Flotation Deinking A program of research has produced significant findings for a number of technologies focused on deinking. First, flotation deinking through flocculation of fine ink particles could be improved using synthetic copolymers. Second, findings indicated that polyalkylene oxide/fatty acid mixture, common surfactant blend in flotation deinking systems, has a dual role in separation of ink particles. Polyalkylene oxide serves as a frother, building stable froth layer that allows the floated ink particles to be skimmed from the top of the flotation cell. The fatty acids activated by calcium ions serve as collector and promote attachment of ink particles to gas bubbles. Finally, Atomic Force Microscopy (AFM) has been applied to recovered paper deinking systems for measuring the interfacial forces acting between pulp particulates. This new analytical technique mimics the conditions of recovered paper pulping and deinking separation at a micro scale. A new procedure for the preparation of spherical toner has been developed in collaboration with the University of Utah. Next, systematic measurements of interfacial forces in flotation deinking systems have been undertaken. For example, it was found that attractive hydrophobic forces are the dominant forces in flotation deinking systems. The repulsive forces are only significant in low ionic strength solutions. This observation has important practical implications indicating that the process water used in the paper recycling mill should carry enough dissolved ions to eliminate the negative effect of an energetic barrier associated with negative surface potentials on water-air and ink-water interfaces, on the attachment of ink particles to gas bubbles. It was further shown that the range of hydrophobic forces increases and the energy barrier decreases in the presence of calcium carboxylate. |
Using Flotation Separation Technology for Mineral Processing Chemistry This program of research, conducted in collaboration with colleagues at the University of Utah and the University of British Columbia, is focused on studying fundamentals of flotation separation technology for a number of different minerals processing systems. For example, an improved experimental procedure to measure contact angle has been consolidated with coal surface preparation involving polishing with abrasive paper, alumina powder and a cloth, followed by ultrasonic and mechanical cleaning. Specifically, the captive-bubble measuring technique has been compared with the sessile-drop technique and the former has been recommended for the examination of the hydrophobic properties of coal surfaces. The research results reveal that an important factor in analysis of contact angle variation on coal surfaces is the size of the hydrophilic mineral inclusions. In another line of inquiry, fundamental studies of mechanisms of bitumen release from oil sands, its attachment to and spreading over the gas bubble surface allowed the development of a technology to improve the hot-water processing of Utah oil sands. |
Free Machining Brass Alloys Tonnage quantities of leaded brasses are used in manufacturing plumbing fittings and fixtures. The lead, which appears as small inclusions in the microstructure, promotes efficient and precise machining. There is evidence indicating that minute quantities of lead dissolved from these alloys by drinking water may have adverse health effects and, for this reason, there is an urgent need to develop free machining alloys that do not contain lead. The means by which lead enhances machinability is not well understood but it may have simultaneous roles in lubrication and in local embrittlement processes. This program of research has the objective the characterization of the elemental cutting and fracture processes. |
Aqueous Corrosion of Copper Copper is generally extremely resistant to corrosive attack by water. However, certain municipal well waters cause pitting attack of copper water tubes. The attack involves the development of a local occluded electrochemical cell, covered by a copper oxide membrane, within which there is an enriched chloride environment. As the demand for fresh water continues to grow, there is an increasing use of water from brackish wells and increasing incidence of damage by this type of corrosion. This program of research is designed to yield a better understanding of the phenomenon. |
Materials Processing, Prototyping and Recycling  This research program is focused on the processing, prototyping and recycling of plastics and composite materials. Recent focus has been on the effects of flatwise tensile strength and shear strength when using recycled epoxy/fiberglass composite powder as a filler material in fiberglass and foam core sandwich panels. Additional work has been devoted to an alternative mechanical peel testing method for composite fiberglass foam core sandwiches. |
Elucidating and Manipulating the Role of Malate in the Maintenance of Stomatal Aperture  The purpose of this research project is to use genetic engineering to alter plant responses to growth under irrigation. Irrigation is widely used to prevent crop losses due to drought. In the United States, approximately 70% of the water diverted by humans is used to irrigate crops. Irrigation has dried up rivers and caused salinization of crop land, which reduces crop productivity. Genetically modified crops that use less water under irrigation conditions have the potential to save massive amounts of irrigation water and to reduce the destruction of farm land.
The majority of water used by plants is lost to the atmosphere through openings called stomata on leaf surfaces. Specialized guard cells that border the stomata control stomatal opening and closing through changes in the concentrations of certain ions in the guard cells. Prof. Laporte's research focuses on one of these ions, malate, which is maintained at high concentrations in guard cells when stomata are open. The metabolism of malate is linked to stomatal closure. Prof. Laporte will study the enzyme that metabolizes malate to look for ways of altering its activity, thereby modulating the size of the stomatal opening while maintaining the stomatal function critical to optimal plant growth.
The long-term goals of this project include not only a better understanding of the way in which malate metabolism in guard cells regulates the size of the stomatal opening, but also the actual molecular engineering of plants with conservative water use under irrigation. In order to accomplish this, Prof. Laporte will conduct genetic studies of the gene for the malate-metabolizing enzyme, identifying which form of the enzyme is made in guard cells. She will then evaluate the size of the stomatal opening and the use of water in plants that make more the metabolizing enzyme in guard cells than usual, plants that make no metabolizing enzyme in guard cells, and plants that make a mutant metabolizing enzyme in guard cells. These experiments will provide the information Prof. Laporte will use to engineer a plant that uses less irrigation water.
Through this research project, Prof. Laporte will also contribute to the training of undergraduate students. Eastern Michigan University has a diverse student body of high-quality undergraduates who are interested in one-on-one training with faculty members. Although many EMU students go on to graduate or professional school or join the scientific workforce; an even larger number become K-12 teachers. While pursuing the goals of this research, Prof. Laporte will train promising undergraduate students, including members of underrepresented minorities, who will become the next generation of scientists and teachers. The extensive connections between EMU and the local K-12 teaching community provide opportunities for high school students, as well as current and future teachers, to learn from and become involved in Prof. Laporte's research program. Many of the molecular, biochemical, and physiological techniques used in this project, along with the accompanying critical thinking skills, can be adapted for use in high school classrooms. |
Rhizosphere Influence on Hydrocarbon Metabolizing Microorganisms The goal of this project is to use cultivation and non-cultivation based methods to characterize the microbial populations associated with plant rhizospheres in hydrocarbon-impacted soils. A series of plots have been established in polynuclear aromatic hydrocarbon (PAH) impacted soils that have been planted with species native to Michigan. Preliminary results with these plots indicate that individual plant species have different effects on the extent of hydrocarbon removal. In this research project, experiments will be conducted to evaluate the different influences that unique plant species have on the microbial communities inhabiting the rhizospheres. This will be performed by analyzing soil samples collected from different plots at various time intervals. Microbial communities will be characterized by 1) sequencing a gene that will enable the identification of microorganisms present (16S rRNA genes) 2) sequencing genes involved in PAH-degradation (PAH dioxygenases), and 3) comparing carbon utilization profiles of rhizosphere samples. It is anticipated that these experiments will reveal microbiological factors that enable some plants to accelerate the removal of PAHs from contaminated soils, whereas others hinder their removal. The broader impacts include developing an ecological framework for understanding how an applied technology like phytoremediation can be optimized. Some aspects of this project will also be integrated into a semester long cooperative laboratory experience for a microbial ecology and plant physiology class taught during the same semester. Further, this support will be used to increase research opportunities for underrepresented populations through local outreach and through additional, formal NSF channels (e.g. REU and RET supplements). |
Biogeochemical Exploration of Acidic and Neutral Hypersaline Environments of Australia This is a collaborative project of Drs. Melanie R. Mormile, Francisca E. Oboh-Ikuenobe (University of Missouri-Rolla), and Kathleen C. Benison (Central Michigan University) to determine if evaporites truly trap a representative population of microorganisms from hypersaline environments. If this is found to be true, these findings can possibly be extrapolated to microorganisms entrapped in ancient or possibly extraterrestrial evaporites and used to describe previous microbial communities and therefore, make interpretations about past water chemistries and past climates. Microorganisms represent the basic life forms existing in most environmental settings. They are sensitive to climatic parameters, and can influence water chemistry, biological activity, and mineralization. Evaporite minerals are a wealth of paleoenvironmental data due to their sensitivity to climate, water chemistry, and hydrology. In addition, evaporites can form in extreme environmental conditions, such as extremely acid saline lakes in Western Australia. These lakes might serve as good analogs to Mars. Traditionally, studies of evaporite settings and their deposits have overlooked microorganisms largely because they are generally poorly preserved in the rock record. However, through this research, answers to the following questions will be found: What microorganisms are present in the lake waters, groundwaters, and sediments of acid and neutral saline lake environments? Are the microorganisms found living in the waters represented in the fluid inclusions of the evaporite minerals? Are the microorganisms specific acidophiles? What role did the microorganisms play in the evolution of the water chemistry? To answer these questions, a sampling trip will be made to Australia to collect a comprehensive set of lake water, groundwater, evaporite, and siliciclastic sediment samples. The following objectives will be achieved: 1. Identify and compare the biological remains in halite and gypsum with those in their parent waters and sediments. Both traditional culture methods and molecular biology techniques will be used to compare the microbial populations in the environments listed above. 2. Grow evaporite crystals under laboratory conditions to study selected environmental influences on crystal formation and the microorganisms that become entrapped. 3. Identify any differences in microorganisms (ranging from prokaryotes to freshwater dinoflagellates and algae) between neutral and moderately acidic saline lakes and groundwaters in Victoria and Western Australia, between neutral and extremely acidic saline lakes within a small region of Western Australia, as well as among extremely acidic saline lakes and groundwaters in Western Australia. The 16S rDNA from the bacteria isolated from these environments will be sequenced and compared. 4. Constrain depositional, environmental, and climatic conditions using basic sedimentology, petrography, fluid inclusion studies, and palynology. Sedimentary structures and grain characteristics will be used to trace depositional history.
We anticipate that novel microorganisms will be found. These organisms can possibly be used for the bioremediation of contaminated sites that are impacted by extremes in saline and acidic conditions. In addition, our findings will have implications for future Mars research and the possibility that life can occur on planetary bodies besides Earth. Of all the planetary bodies explored, Mars most closely resemble Earth. In particular, terrestrial acid sedimentary systems are similar in general mineralogy, geochemistry, and geomorphology to the Martian surface. Furthermore, this project will be responsible for the training of students ranging from undergraduate level to Post-Doctoral students. There is also a significant outreach component that includes a partnership with the St. Louis Science Center as well as a course on the geology and microbiology of extreme environments targeted towards K-12 educators. |
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