Browsing by Subject "pH"

Now showing 1 - 3 of 3
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    An In Vitro Study Of Ph Changes With Endosequence Bc Root Repair Material Fast Set Putty In Simulated Resorptive Defects
    (2018-08) Kickertz, Katie
    One of the challenges to endodontic treatment is external inflammatory root resorption, a destructive process which destroys the radicular portion of the tooth when under pathologic states. Treatment has traditionally been via long-term placement of an intracanal medicament of calcium hydroxide. Calcium hydroxide is antimicrobial, able to dissolve tissue, inhibit resorption and induce hard tissue formation. It has an alkaline pH, which disrupts bacterial cell wall metabolism. Cons to its use include potential for tooth fracture and multiple appointments needed for effect on the resorption process. The purpose of this study was to compare in vitro the effects of intracanal placement of Endosequence BC RRM Fast Set Putty and calcium hydroxide on hydroxol ion diffusion through dentin of teeth with simulated root surface cavities, mimicking external resorptive lesions. The goal was to determine if Endosequence BC RRM Fast Set Putty is a conceivable alternative to calcium hydroxide in cases of external inflammatory resorptive lesions.
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    Research on Influential Factors for Producing Nanoparticle Enhanced Sol-Gel Composites
    (2024-04) Boyer, Chase W; Xie, Weiguo
    The sol-gel process provides a cheap and simple method for making ceramic materials. The benefits of producing ceramic materials through the sol-gel process are production at significantly lower temperatures than traditional methods and the ability to be produced in intricate 3D shapes. A major problem holding back the sol-gel ceramics is their lack of structural integrity. This research aimed to find the optimal processing conditions to increase the hardness of the ceramic. The impact of HCl pH, Titania particle amount, Dry temperature, Drying time, and mixing time were investigated through an L16 (45) orthogonal design. The data from all 16 experiments showed that the amount of titania particles had the largest effect on hardness. Hardness increased as the titania particle amount increased. The effect on drying time and drying temperature showed a sweet spot around 2 days and 50℃ where the hardness increased without the risk of fracturing the ceramic. If the sol-gel was dried at too high of a temperature and/or for too long, the resulting ceramic would thermally degrade. The pH of the HCl used in the solution was optimal at a pH of 3. The mean hardness values of pH 1 and 2 were not much lower, but the mean hardness was significantly lower at a pH of 4 and was the most inhibiting factor throughout all the experiments. The mix time was shown to have an optimal condition of 3 minutes of mixing before drying. This goes against intuition, however, it can be noted that there existed room for error due to the hand mixing of the sol-gels. The experiments provided a great insight into how the processing conditions of the sol-gel affect the final ceramic. Further experiments are required to decode and optimize the conditions for a structurally stable sol-gel ceramic. The mitigation of human and machine error alongside an investigation into the effect of shape on hardness as well as finding optimal conditions for creating a single large grain will be required to create a sol-gel ceramic that can be applied industrially.
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    Temporal Fluctuations in Carbonate System Variables of Lake Superior Tributaries
    (2023-06) Kittaka, Payton
    Northeastern Minnesota, like other regions, has exhibited recent climate change effects; predicted changes over the next century include longer dry periods, less snow accumulation, and more large rain and snow events. Carbonate system variables including pH, total inorganic carbon (TIC) concentrations, and total alkalinity (TA) are all highly dependent on and have feedbacks with these climate factors. These variables can also influence the quality of life for various species, such as trout, which rely on many streams along the north shore of Lake Superior for spawning habitats. Therefore, studying the current conditions of waterbodies in northeastern Minnesota is crucial for setting a baseline to estimate and predict the potential ramifications of regional climate change. Amity Creek, Tischer Creek, and the St. Louis River are three tributaries of Lake Superior varying in watershed size and overall length. This study investigated how pH, TA, and TIC of these tributaries are affected by seasonality, stormflow, and diurnal conditions, as well as their inter-annual variability based on available data. Seasonal sampling showed that carbonate system variables were relatively stable throughout fall before decreasing to minimum levels in spring when large freshets and rainfall events occurred. Carbonate system variables reached maximum levels in the summer when water and air temperatures were greatest in the sampling period and photosynthetic activity levels were also likely the highest. Autumn levels were similar to summer levels. During storm events, pH, TIC, and TA decreased compared to baseflow. Specific trends during storms were dependent on storm length, total precipitation, and prior precipitation amounts. Over a diurnal period in Amity Creek, pH increased during the morning hours to a midday maximum and then decreased. TIC and TA increased throughout the day, likely due to the increased influence of groundwater as the stream recovered from a rain event that occurred 4 days prior. Historically, pH has been increasing in Amity Creek and the St. Louis River, while Tischer Creek shows no trend. However, Tischer Creek and Amity Creek appear highly susceptible to inter-annual variability. Alkalinity trends were more difficult to assess due to data availability. However, where available, alkalinity trends closely follow the pH trends in the case of Amity Creek, while in the St. Louis River, alkalinity remained constant. In Tischer Creek, hardness data was used as a proxy variable for alkalinity. Hardness levels appeared to be increasing but had notably similar inter-annual variability as pH. This study demonstrates how carbonate system variables in streams and rivers can shift over long temporal scales, but more importantly how much variability can occur over the course of storm events and hours.