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Differential Photometric Analysis Of Exoplanet Candidates TOI-1362.01, TOI-2290.01, TOI-6010.01, And TOI-6324.01
No full textTo maximize the science return from the Transiting Exoplanet Survey Satellite (TESS), the TESS Follow-up Observing Program (TFOP) was created to network scientists and observatories to conduct follow-up observations of potential exoplanets. As members of TFOP-Subgroup 1, we observed four exoplanet candidates: TOI-1362.01, TOI-2290.01, TOI-6010.01, and TOI-6324.01 using the University of North Dakota Space Studies Observatory. The TOI observations were conducted from 31 October 2024 – 15 November, 2024 UTC. AstroImageJ software was used to perform differential photometry and, if a transit event was observed, determine orbital parameters and physical characteristics. Each of the target’s light curves was modeled and parameters adjusted to find the lowest combination value of ??2, Bayesian Information Criterion (BIC), and the RMS error. We present modeled transit light curves for exoplanet candidates TOI-1362.01, TOI-2290.01, TOI-6010.01, and TOI-6324.01. Our results suggest that transit events were not observed for any of the four TOIs. Follow-up observations and high-precision radial velocity measurements are needed to either eliminate or strengthen the candidacy of TOI-1362.01, TOI-2290.01, and TOI-6010.01
Dynamic Techno-Economic Analysis Of Advanced Configuration Of Chemical Absorption Carbon Capture Technology Integration With Natural Gas Combined Cycle
No full textCO2 emissions from the power sector continue to increase annually owing to global economic growth and the electrification of end-use energy consumption. Natural gas power plants are recognized for their flexibility in ensuring grid stability. The rise in the share of renewable energy sources in the grid has led to part-load operation and reduced capacity factors for fossil fuel power plants. The importance of carbon capture technology (CCT) in reducing CO2 emissions is generally recognized. This study investigates the integration of post-combustion carbon capture (PCC) technology in the power sector as a means of addressing three closely related challenges: first, reducing the carbon emission intensity in the power sector; second, the impacts of part load operation on the technical and cost performance of integrated gas plants and PCC; and third, estimation of realistic capacity factors for cost studies and decision-making. This work adopted analytical methods, process modelling, and integrated energy systems modelling. Two process configurations of MEA-CO2 absorption, namely the conventional and Lean Vapor Recompression (LVR), are investigated at base load and part-load outputs of the Natural Gas Combined Cycle (NGCC). The columns’ performances were verified, and L/G values are below 0.78.Technoeconomic assessment (TEA) drives policy development and decision-making in technology adoption. Static TEAs are unable to capture vital aspects when compared to a dynamic TEA, which captures the changes in cost and technical variables over the plant lifetime. The Levelized Cost of Electricity (LCOE) would likely be above 110 $/MWh due to operational flexibility in the grid. Furthermore, a load dispatch model with power supply constraint of the NGCC-PCC in a renewable energy-dominant grid shows that the net present value remains negative at all loads. The Monte Carlo simulations and model optimization indicate profitability in a favorable CO2 market environment, alongside regulatory frameworks such as carbon taxes and adequate incentives, which are currently absent in the United States. The NGCC-PCC is a low-carbon energy system that must operate at base load and high capacity factors for PCC technology to aid in achieving the net-zero objective
Numerical And Experimental Simulations Of Fluid Flow In X-Crossing Rough Fracture Surfaces
No full textThis research investigates the complex dynamics of fluid flow through intersecting rough fracture surfaces. Addressing the gaps in understanding the interplay between fracture roughness and fluid flow behaviors, this work employs a combination of numerical modeling and experimental simulations.Utilizing 3D printing technology, realistic fracture models were fabricated to replicate rough fracture geometries and intersection angles. These models were subjected to fluid flow experiments to explore linear and nonlinear flow regimes. Additionally, computational fluid dynamics (CFD) simulations provided insights into the impacts of fracture roughness, aperture, and intersection angles on permeability and flow dynamics. A critical analysis of fracture surface properties such as roughness, aperture and intersecting angles variation conducted to elucidate their roles in flow regime transitions and deviations from the cubic law. The study reveals significant deviations from traditional parallel-plate flow models in fractures with high roughness or complex intersection geometries. Nonlinear flow behaviors, including eddy formation and increased flow tortuosity, were identified as key contributors to these deviations. The findings have important implications for optimizing fluid transport in subsurface reservoirs and contribute to developing more accurate discrete fracture network (DFN) models for energy and environmental applications. This integrated approach of experimental and numerical investigations enhances the understanding of fluid flow mechanisms in fractured media, providing a foundation for improving the efficiency and safety of subsurface operations
Set of Soapstone Shishi
No full textSoapstone carving of a Shishi or a Foo Dog or a Lion Dog. The male (left) has his paw on a ball that represents the material. The female (right) has her paw on a cub that represents the immaterial. They come in pairs and are often incorporated as part of Feng Shui.https://commons.und.edu/fritzcollection/1207/thumbnail.jp
Chinese Brass Vase
No full textSmall brass vase that comes with a detachable stand. There are bird motifs on the side that the handles attach to.https://commons.und.edu/fritzcollection/1211/thumbnail.jp
Red Chinese Bowl
No full textRed bowl with tree designs on the inside, bottom of the bowl is stamped.https://commons.und.edu/fritzcollection/1214/thumbnail.jp
