Scholarship & Research
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Item A fiber optic array for the detection of sub-surface carbon dioxide at carbon sequestration sites(Montana State University - Bozeman, College of Engineering, 2014) Soukup, Benjamin John; Chairperson, Graduate Committee: Kevin S. RepaskyA fiber sensor array for sub-surface CO 2 concentrations measurements was developed for monitoring geologic carbon sequestration sites. The fiber sensor array uses a temperature-tunable distributed feedback (DFB) laser outputting a nominal wavelength of 2.004 microns. Light from this DFB laser is directed to one of the four probes via an in-line 1x4 fiber optic switch. Each of the probes is placed underground and utilizes filters that allow only soil gas to enter the probe. Light from the DFB laser interacts with CO 2 within the probe before being directed back through the switch. The DFB laser is tuned across two CO 2 absorption features where a transmission measurement is made, allowing the CO 2 concentration to be retrieved. This process is repeated for each probe, allowing CO 2 concentration measurements to be made as a function of time for each probe. The fiber sensor array was deployed for fifty-eight days at the Zero Emission Research Technology (ZERT) field site and for a twenty-eight day period at the Kevin Dome geologic carbon sequestration site. Background measurements indicate the instrument can monitor background levels as low as 1,000 parts per million (ppm). During a thirty-four day sub-surface CO 2 release, elevated CO 2 concentrations were readily detected by each of the four probes with values ranging to over 60,000 ppm.Item Multi-spectral imaging of vegetation for CO 2 leak detection(Montana State University - Bozeman, College of Engineering, 2011) Hogan, Justin Allan; Chairperson, Graduate Committee: Joseph A. ShawThough its status as a crisis situation remains the subject of much debate [1,2] there does exist evidence that global warming is a real phenomenon [3] and that its processes are to some degree enhanced by anthropogenically introduced greenhouse gases, perhaps most notably carbon dioxide (CO 2) [3]. This claim is backed by observations of increasing atmospheric CO 2 concentrations from nearly 280-ppm around 1750 to 360 ppm in 1995 [4]. By the end of 2010, this number was up to approximately 390 ppm [5]. To reduce human influence on the global environment, carbon capture and sequestration (CCS) is proposed as a means of collecting CO 2 generated through industrial and consumer processes and sequestering it so as not to release it into the atmosphere, thereby reducing atmospheric concentrations of the gas. Suggested methods of sequestration include direct deep-sea injection [6], soil sequestration through improved land use and management practices [7], and geological carbon sequestration in which captured carbon is injected into underground geological features. This research focuses primarily on development and testing of a leak detection technology for deployment to geological sequestration sites. A diverse technology portfolio will be required to implement safe and efficient sequestration solutions [8]. Included in this portfolio is technology capable of monitoring sequestration site integrity; detecting and signaling leakage, should it occur. Early leak detection is paramount to ensuring on-site safety and to minimize, or at least understand, potentially harmful environmental leak effects.Item Measurements of plant stress in response to CO2 using a three-CCD imager(Montana State University - Bozeman, College of Engineering, 2008) Rouse, Joshua Hatley; Chairperson, Graduate Committee: Joseph A. ShawIn response to the increasing atmospheric concentration of greenhouse gasses, such as CO2 produced by burning fossil fuels, which is very likely linked to climate change, the Zero Emissions Research Technology (ZERT) program has been researching the viability of underground sequestration of CO2. This group's research ranges from modeling underground sequestration wells to detection of leaks at test sites. One of these test sites is located just west of Montana State University in Bozeman, MT, at 45.66°N 111.08°W. At this site experiments were conducted to assess the viability of using multispectral imaging to detect plant stress as a surrogate for detecting a CO2 leak. A Geospatial Systems MS3100 multispectral imager, implemented in color-infrared mode, was used to image the plants in three spectral bands. Radiometric calibration of the output of the imager, a digital number (DN), to a reflectance was achieved using a grey card and spectralon reflectance panels. To analyze plant stress we used time series comparisons of the bands and the Normalized Difference Vegetation Index (NDVI), computed from the red and near-infrared band reflectances. Results were compared with rainfall, soil moisture, and CO2 flux data. The experiment was repeated two years in a row; the first from June 21, 2007 to August 1, 2007 and the second from June 16, 2008 to August 22, 2008. Data from the first experiment showed that plants directly over the leak were negatively affected quickly, while plants far from the pipe were affected positively. Data from the second experiment showed that the net effect of leaking CO2 depends on the relationship between CO2 sink-source balance and vegetation density. Also, due to the strong calibration techniques employed in 2008, the imaging system was able to see the effects of water and hail on the vegetation. We have also found a way to image continuously through the day, not having to worry about clouds or sun-to-scene/scene-to-imager angle effects. This system's easy setup, automation, all-day imaging capability, and possibility for low cost makes it a very practical tool for plant stress measurements for the purpose of detecting leaking CO2.