Browsing by Subject "methane"
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Item Data and code for "Design and evaluation of a low-cost sensor node for near-background methane measurement"(2023-11-20) Furuta, Daniel CR; Wilson, Bruce N; Presto, Albert; Li, Jiayu; furut011@umn.edu; Furuta, Daniel CRCleaned data and supporting code for "Design and evaluation of a low-cost sensor node for near-background methane measurement". The data was collected at two research sites in 2022 and 2023, and the analysis code was used to generate the model and figures in the paper.Item Dataset for "Characterization of inexpensive MOx sensor performance for trace methane detection"(2022-03-23) Furuta, Daniel; Sayahi, Tofigh; Li, Jinsheng; Wilson, Bruce; Presto, Albert; Li, Jiayu; lijiayu@umn.edu; Li, Jiayu; University of Minnesota BBE Air and Aerosol Sensing GroupLaboratory calibration data for three replicates each of five types of inexpensive methane sensors in support of a study characterizing sensor suitability for atmospheric monitoring, with particular attention to sensitivity to humidity and temperature. Sensor performance from ambient levels to 10ppm was characterized with decaying methane pulses at five different temperatures. Methane, water vapor levels, and temperature were monitored with reference instruments.Item Electrochemical Removal of Aqueous Sulfide from Swine Manure(2018-06) Wang, YuchuanHydrogen sulfide (H_2 S) produced in swine manure pit storage is a safety hazard to both human and animals. An electrochemical treatment based on low carbon steel electrodes was developed to reduce aqueous sulfide and emitted H_2 S concentration from manure storage. At the selected condition (Applied voltage = 0.7 V, immersed electrode surface area = 19 cm^2/L, initial sulfide concentration = 5 - 6 mM, operation temperature = 19 °C), the process achieved an average sulfide removal rate of 2.60 mg S^(2-)/(cm^2⋅day) for the zero order kinetic model, and a rate coefficient of 0.275 /day for the 1st order kinetic model. Constant disturbance created to simulate the pumping event was found greatly accelerated the H_2 S release directly from the manure liquid; however, removals of over 90% sulfide and H_2 S significantly reduced the risk. Methane concentration went higher as the sulfide removal; 46% higher concentration was found at 95% sulfide removal from the initial concentration over 6 mM. Different from the electrochemical sulfide removal from less viscous wastewater, low voltage applied in this study was proved feasible to maximize the precipitation and minimize the flotation in swine manure. The installation of this technology may reduce the risk of manure pump-out in terms of H_2 S over-exposure and may be applied in similar circumstances where H_2 S poses threats to health and life.Item Evaluating on-farm methods for estimating gas emissions and quantifying risk of disease transmission for livestock barns(2023-08) Warmka, AnnaThe need for producers to demonstrate the environmental and economical sustainability of their operations is driven by several stakeholder and consumer groups, creating a call for methods to accurately estimate gas emissions and quantify risk of disease transmission. In this work, I first provide background on the mechanisms of gas emissions from deep-pit swine operations and a summary of current emission estimation strategies in the literature. Next, I present one thesis project demonstrating the opportunities and limitations to applying a mass balance approach to estimate methane and ammonia emissions from deep-pit swine barns. Through this project, different mass balance approaches are evaluated against each other and typical emission modeling approaches. Findings from this project show that there are limitations to the application of a mass balance approach in swine barns, particularly related to in-barn sample collection and dataavailability. Then, I present a second thesis project identifying opportunities and limitations to using a fluorescent gel as a proxy for disease transfer in biosecurity research. In this project, I present a method to quantify the luminance of the fluorescent gel and investigate the factors important in measuring the transfer of gel from one surface to another. Findings from these two projects provide a framework for the methods needed to conduct research in gas emissions and biosecurity in livestock operations. Understanding the current state and limitations of these methods is important to consider when applying them to future research, and the current limitations presented provide an outline for future work needed in these fields.Item Solar Synthesis Gas Production via the Thermochemical Cerium Oxide Redox Cycle: Inert-Swept and Methane-Hybridized Reduction(2016-01) Krenzke, PeterThe cerium oxide (ceria) redox cycle is evaluated as a means for producing synthesis gas from carbon dioxide and water using solar energy. Two options are considered for facilitating oxygen removal during ceria reduction: inert gas sweeping and reaction with methane to produce synthesis gas. Thermodynamic process analyses are developed to ascertain the viability of the cycle and identify requirements for high efficiency under the assumption of equilibrium chemistry. A parametric experimental study is conducted to determine the impact of temperature and methane flow rate on methane conversion, syngas selectivity, oxidizer conversion, and the solar-to-fuel efficiency.