NEW MICROFLUIDIC SYSTEM TO INCREASE ROBUSTNESS OF ELECTRODE PERFORMANCE AND DEVELOP POINT-OF-CARE HEMATOCRIT DEVICE

The present dissertation aimed to develop a new microfluidic system for a point-of-care hematocrit device. Stabilization of microfluidic systems via surfactant additives and integration of semipermeable SnakeSkin® membranes was investigated. Both methods stabilized the microfluidic systems by controlling electrolysis bubbles. Surfactant additives, Triton X-100 and SDS stabilized promoted faster bubble detachment at electrode surfaces by lowering surface tension and decreased gas bubble formation by increasing gas solubility. The SnakeSkin® membranes blocked bubbles from entering the microchannel and thus less disturbance to the electric field by bubbles occurred in the microchannel. Platinum electrode performance was improved by carbonizing electrode surface using red blood cells. Irreversibly adsorbed RBCs lysed on platinum electrode surfaces and formed porous carbon layers while current response measurements. The formed carbon layers increase the platinum electrode surface area and thus electrode performance was improved by 140 %. The microfluidic system was simplified by employing DC field to use as a platform for a point-of-care hematocrit device. Feasibility of the microfluidic system for hematocrit determination was shown via current response measurements of red blood cell suspensions in phosphate buffered saline and plasma media. The linear trendline of current responses over red blood cell concentration was obtained in both phosphate buffered saline and plasma media. This research suggested that a new and simple microfluidic system could be a promising solution to develop an inexpensive and reliable point-of-care hematocrit device.

Assessing drinking water quality at source and point-of-use : a case study of Koila Bamana, Mali, West Africa

Ensuring water is safe at source and point-of-use is important in areas of the world where drinking water is collected from communal supplies. This report describes a study in rural Mali to determine the appropriateness of assumptions common among development organizations that drinking water will remain safe at point-of-use if collected from a safe (improved) source. Water was collected from ten sources (borehole wells with hand pumps, and hand-dug wells) and forty-five households using water from each source type. Water quality was evaluated seasonally (quarterly) for levels of total coliform, E.coli, and turbidity. Microbial testing was done using the 3M Petrifilm™ method. Turbidity testing was done using a turbidity tube. Microbial testing results were analyzed using statistical tests including Kruskal-Wallis, Mann Whitney, and analysis of variance. Results show that water from hand pumps did not contain total coliform or E.coli and had turbidity under 5 NTUs, whereas water from dug wells had high levels of bacteria and turbidity. However water at point-of-use (household) from hand pumps showed microbial contamination - at times being indistinguishable from households using dug wells - indicating a decline in water quality from source to point-of-use. Chemical treatment at point-of-use is suggested as an appropriate solution to eliminating any post-source contamination. Additionally, it is recommended that future work be done to modify existing water development strategies to consider water quality at point-of-use.

Effective water treatment for rural communities in Suriname : a comparison of point-of-use ceramic filters and centralized treatment with sand filters

For countless communities around the world, acquiring access to safe drinking water is a daily challenge which many organizations endeavor to meet. The villages in the interior of Suriname have been the focus of many improved drinking water projects as most communities are without year-round access. Unfortunately, as many as 75% of the systems in Suriname fail within several years of implementation. These communities, scattered along the rivers and throughout the jungle, lack many of the resources required to sustain a centralized water treatment system. However, the centralized system in the village of Bendekonde on the Upper Suriname River has been operational for over 10 years and is often touted by other communities. The Bendekonde system is praised even though the technology does not differ significantly from other failed systems. Many of the water systems that fail in the interior fail due to a lack of resources available to the community to maintain the system. Typically, the more complex a system becomes, so does the demand for additional resources. Alternatives to centralized systems include technologies such as point-of-use water filters, which can greatly reduce the necessity for outside resources. In particular, ceramic point-of-use water filters offer a technology that can be reasonably managed in a low resource setting such as that in the interior of Suriname. This report investigates the appropriateness and effectiveness of ceramic filters constructed with local Suriname clay and compares the treatment effectiveness to that of the Bendekonde system. Results of this study showed that functional filters could be produced from Surinamese clay and that they were more effective, in a controlled laboratory setting, than the field performance of the Bendekonde system for removing total coliform. However, the Bendekonde system was more successful at removing E. coli. In a life-cycle assessment, ceramic water filters manufactured in Suriname and used in homes for a lifespan of 2 years were shown to have lower cumulative energy demand, as well as lower global warming potential than a centralized system similar to that used in Bendekonde.

An Experience-Driven Pedagogy for the Instruction of Software Testing in Computer Science

In the realm of computer programming, the experience of writing a program is used to reinforce concepts and evaluate ability. This research uses three case studies to evaluate the introduction of testing through Kolb's Experiential Learning Model (ELM). We then analyze the impact of those testing experiences to determine methods for improving future courses. The first testing experience that students encounter are unit test reports in their early courses. This course demonstrates that automating and improving feedback can provide more ELM iterations. The JUnit Generation (JUG) tool also provided a positive experience for the instructor by reducing the overall workload. Later, undergraduate and graduate students have the opportunity to work together in a multi-role Human-Computer Interaction (HCI) course. The interactions use usability analysis techniques with graduate students as usability experts and undergraduate students as design engineers. Students get experience testing the user experience of their product prototypes using methods varying from heuristic analysis to user testing. From this course, we learned the importance of the instructors role in the ELM. As more roles were added to the HCI course, a desire arose to provide more complete, quality assured software. This inspired the addition of unit testing experiences to the course. However, we learned that significant preparations must be made to apply the ELM when students are resistant. The research presented through these courses was driven by the recognition of a need for testing in a Computer Science curriculum. Our understanding of the ELM suggests the need for student experience when being introduced to testing concepts. We learned that experiential learning, when appropriately implemented, can provide benefits to the Computer Science classroom. When examined together, these course-based research projects provided insight into building strong testing practices into a curriculum.