Thermal expansion of kyanite at ambient pressure: An X-ray powder diffraction study up to 1000 °C

AbstractThe thermal expansion coefficients of kyanite at ambient pressure have been investigated by an X-ray powder diffraction technique with temperatures up to 1000 °C. No phase transition was observed in the experimental temperature range. Data for the unit-cell parameters and temperatures were fitted empirically resulting in the following thermal expansion coefficients: αa = 5.8(3) × 10−5, αb = 5.8(1) × 10−5, αc = 5.2(1) × 10−5, and αV = 7.4(1) × 10−3 °C−1, in good agreement with a recent neutron powder diffraction study. On the other hand, the variation of the unit-cell angles α, β and γ of kyanite with increase in temperature is very complicated, and the agreement among all studies is poor. The thermal expansion data at ambient pressure reported here and the compression data at ambient temperature from the literature suggest that, for the kyanite lattice, the most and least thermally expandable directions correspond to the most and least compressible directions, respectively

Upholding Social Justice Principles in Carbon Capture and Sequestration: Case of Southeastern Michigan

As the world is grappling with a worsening climate change crisis, there is a growing consensus that the world might need to scale up carbon dioxide removal activities to complement mitigation and adaptation efforts. Climate change and decarbonization can cause disproportionate impacts on disadvantaged communities, such as increased energy burden and job displacement, especially in regions such as Southeastern Michigan. Thus, it is important to prioritize the needs and concerns of these communities by implementing targeted policies and investments, increasing awareness, and empowering them to participate in decision-making processes. In particular, the Justice40 Initiative can be a momentum to support this transition process. The Justice40 Initiative’s goal is to ensure that 40% of the overall benefits of certain Federal investments flow to disadvantaged communities. In this context, this project aims to study the feasibility of Carbon Capture and Sequestration (CCS) in the Southeastern Michigan region while promoting a sustainable environment and transition through the Justice40 Initiative. While there are several research projects that focus on the technological aspect of CCS, studies to understand the policy, socioeconomic, and social justice aspects of CCS deployment are still lagging. As societal consideration is a key component of success for any CCS initiative, it is imperative to advance the social aspect in addition to providing economic and policy incentives that can catalyze deployment at scale. With the geographical focus on Southeastern Michigan, our study utilizes three research approaches: (1) geospatial analysis, (2) social life cycle assessment (S-LCA), and (3) stakeholder engagement. This report presented our results of literature review, analysis and the recommendations for policymakers and project developers. The geospatial analysis presents the reclassification of pollution burden based on the burden indicators such as energy and housing from the Climate and Economic Justice Screening Tool. Further, the cluster analysis exhibited spatial distribution patterns and the relationships with the emitter location and disadvantaged communities. The social life cycle assessment presented a framework for analysis focusing on potential social issues and opportunities from the lens of sustainable development's three pillars: People, Planet, and Prosperity. The societal aspect of the development of a CCS facility includes key stakeholder categories, such as workers, society, and local communities. Finally, the stakeholder engagement part presented key insights from diverse stakeholders including public, private, and civil representatives. Participation in conferences and workshops allowed us to interact with several stakeholders and provided valuable insights into conducting social studies while establishing connections with fellow scholars. Overall, our study highlights the importance of engaging with local social groups and the need for ensuring transparency, building credibility, and upholding aspects of recognitional, procedural, and distributional justice. Effective Greenhouse Gas (GHG) emissions control, especially from major sources like power plants, combined with targeted social justice interventions in heavily burdened clusters, is crucial. Addressing labor rights, community engagement, and indigenous rights within the context of CCS projects is paramount to ensuring an equitable and just transition to net-zero emissions. Transparent communication, thoughtful implementation, and genuine stakeholder engagement are essential to ensure equity and leveraging Michigan's geological potential for CCS. This holistic approach will enable the region to navigate the complex interplay between technological advancement, environmental sustainability, and social equity.Master of Science (MS)School for Environment and SustainabilityUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/192881/1/UpholdingSocJustCarbonCapture.pd

Micropipes in SiC Single Crystal Observed by Molten KOH Etching

Micropipe, a “killer” defect in SiC crystals, severely hampers the outstanding performance of SiC-based devices. In this paper, the etching behavior of micropipes in 4H-SiC and 6H-SiC wafers was studied using the molten KOH etching method. The spectra of 4H-SiC and 6H-SiC crystals containing micropipes were examined using Raman scattering. A new Raman peak accompanying micropipes located near −784 cm−1 was observed, which may have been induced by polymorphic transformation during the etching process in the area of micropipe etch pits. This feature may provide a new way to distinguish micropipes from other defects. In addition, the preferable etching conditions for distinguishing micropipes from threading screw dislocations (TSDs) was determined using laser confocal microscopy, scanning electron microscopy (SEM) and optical microscopy. Meanwhile, the micropipe etching pits were classified into two types based on their morphology and formation mechanism

Combined Effect of Silica Nanoparticles and Benzo[a]pyrene on Cell Cycle Arrest Induction and Apoptosis in Human Umbilical Vein Endothelial Cells

Particulate matter (PM) such as ultrafine particulate matter (UFP) and the organic compound pollutants such as polycyclic aromatic hydrocarbon (PAH) are widespread in the environment. UFP and PAH are present in the air, and their presence may enhance their individual adverse effects on human health. However, the mechanism and effect of their combined interactions on human cells are not well understood. We investigated the combined toxicity of silica nanoparticles (SiNPs) (UFP) and Benzo[a]pyrene (B[a]P) (PAH) on human endothelial cells. Human umbilical vascular endothelial cells (HUVECs) were exposed to SiNPs or B[a]P, or a combination of SiNPs and B[a]P. The toxicity was investigated by assessing cellular oxidative stress, DNA damage, cell cycle arrest, and apoptosis. Our results show that SiNPs were able to induce reactive oxygen species generation (ROS). B[a]P, when acting alone, had no toxicity effect. However, a co-exposure of SiNPs and B[a]P synergistically induced DNA damage, oxidative stress, cell cycle arrest at the G2/M check point, and apoptosis. The co-exposure induced G2/M arrest through the upregulation of Chk1 and downregulation of Cdc25C, cyclin B1. The co-exposure also upregulated bax, caspase-3, and caspase-9, the proapoptic proteins, while down-regulating bcl-2, which is an antiapoptotic protein. These results show that interactions between SiNPs and B[a]P synergistically potentiated toxicological effects on HUVECs. This information should help further our understanding of the combined toxicity of PAH and UFP