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Integration of Encapsulated Phase Change Materials into Power Dense Electronic Package Architectures for Enhanced Thermal Buffering
No full textImproving energy resilience requires continuous improvement of power electronic systems focusing on increasing power densities, often limited by the thermal management system performance and requirements. Thermal management systems can be more optimal in thermal energy transfer and more efficient in energy consumption through passive cooling components integration. There are many passive cooling mechanisms that work to store or transfer energy without direct power requirements including phase change materials (PCMs). PCMs are of particular interest because they store large amounts of energy across a phase transition, commonly solid to liquid, and work well as additional thermal buffering within power dense systems. The added thermal buffering can significantly improve efficiency and reliability of power dense electronics by reducing maximum thermal gradients and temperatures around critical components. It is often challenging to incorporate conventional PCMs within electronic architectures in a manner that both provides adequate energy response and protects systems from the liquid phase. The structures needed to enclose these PCMs reduce opportunities to maximize total power density realization. To address this problem, this work uses encapsulated phase change materials (ePCMs) to design stable ePCM based composites for direct integration into existing electronics architectures. ePCMs are micro to nano sized particles with a PCM core surrounded by a protective shell that can be easily integrated into existing matrix materials to provide passive cooling capability without liquid phase concerns. This work integrates ePCMs into dielectric gels and thermal interface materials to design new ePCM laden composites that can directly replace existing electronics materials located near the thermal generation regions. The ePCM composites are tested and compared against their predecessors to characterize the performance improvements and associated tradeoffs of direct implementation in existing electronic configurations
Fragments of a Note Written then Destroyed
No full textFragments of a Note Written then Destroyed is a meditation upon grief, memory, and transience. The titular ‘note’ refers to a lengthy journal entry in which the poet experienced an outpouring of emotion regarding the death of her beloved grandmother (mom’s mom) two years prior. The January 2025 death of the poet’s grandfather (mom’s dad) and the realization that, in the natural order of things, there was no longer anyone standing between death and her mother triggered an extreme and prolonged state of despair. This state culminated in a nearly four-page piece of writing which the poet refers to as “the closest thing I’ve ever written to a suicide note.” The poet tore the note to pieces then set them aside. The poet kept these pieces because, in spite of the darkness they held, they were the fruit of a labor-intensive writing session that the poet was not willing to let go to waste.
The fragments of this note appear alongside ekphrastic poems which are centered upon very old photographs from the childhood of the poet’s grandmother. Taken in Lansing, Michigan from 1947 to 1957, these photographs came into the poet’s possession after her grandmother’s death in December 2022. These photos are themselves fragments—representations of moments past that the poet will never be able to ask her grandmother about. In collecting and responding to these fragments, the poet struggles to find balance between imagination and oblivion
Male and Female Contributions to Sexual Dimorphism
Get PDFSince Darwin, the evolution of sexual dimorphism connects to different evolutionary mechanisms reflecting both natural selection and sexual selection. In primates, body size dimorphism has been attributed to multiple factors, including sexual selection, fecundity selection, ecological selection, and other factors. In contrast, canine tooth size dimorphism has been primarily associated with sexual selection in males with minor change in females, with other factors playing only a secondary role. This suggests that the degree to which body size dimorphism and canine size dimorphism covary, controlling for phylogeny, should reflect the strength of sexual selection. Conversely, the magnitude of divergence between the two dimorphism measures should indicate number of other factors that impact sexual size dimorphism. A key factor that is difficult to tease apart is how the measure of changes in either male or female canine tooth size or body size might impact the magnitude of sexual dimorphism. This study evaluates covariation in body mass dimorphism and canine height dimorphism, and the relative contribution of males and females to the evolution of sexual dimorphism. Tooth size and body mass data were gathered from the literature. The analysis includes PGLS-corrected linear regressions and independent contrasts, and linear parsimony reconstructions. The results of these analyses suggest that sexual selection through the mechanism of male competition is indeed the dominant factor underlying the evolution of both sexual size dimorphism and sexual canine dimorphism, but that other factors impact sexual size dimorphism disproportionately as compared to sexual canine dimorphism. Thus, the use of sexual size dimorphism as a proxy for sexual selection should be approached with caution
Leveraging Machine Learning Models for Enhanced Landslide Prediction in Western North Carolina
No full textLandslides pose significant hazards to human safety, infrastructure, and the environment, particularly in regions of high elevation that experience extended periods of heavy rainfall. This research focuses on preparing and evaluating landslide susceptibility maps (LSMs) for the Blue Ridge Mountains, a portion of the Appalachian Mountains in western North Carolina, utilizing three machine learning algorithms: Logistic Regression, Random Forest, and Gradient Boosting Regression. Sixteen landslide conditioning factors, reflecting topographic, geological, environmental, and anthropogenic influences, were identified for model input. The landslide inventory database, comprising 7,350 locations, was randomly divided into training (80%) and testing (20%) sets. The performance of each model was evaluated and compared using confusion matrices. The Random Forest algorithm had the highest performance in predicting landslide locations, with a strong emphasis on elevation, slope, and proximity to roads as the most influential factors. The Logistic Regression model provided useful insights into the linear relationships between the conditioning factors and landslide susceptibility, performing well in areas where the relationship between predictors and landslide occurrence is more straightforward. In contrast, the Gradient Boosting model, known for its ability to capture complex nonlinear relationships, identified similar critical factors as the Random Forest model but with a higher sensitivity to variations in slope and distance to drainages. The differences in model outcomes can be attributed to the inherent characteristics of the algorithms: Logistic Regression’s simplicity and linearity, Random Forest’s ability to handle complex interactions through ensemble learning, and Gradient Boosting’s strength in optimizing weak learners for more nuanced pattern recognition. Overall, the LSMs produced by these models suggest that 20% of the study area is highly susceptible to landslides. These LSMs can serve as a valuable tool for land use planning, disaster preparedness, and risk mitigation efforts at a large scale
Multi-Decadal Land Change Dynamics in Indonesia: Disentangling the Cycle of Agricultural Land Conversions, Urbanization, and Deforestation
Get PDFLand use and land cover change (LULCC) significantly impacts Earth’s environmental, climatic, and human systems, especially in tropical regions rich in natural resources and undergoing rapid development. This study examined the spatiotemporal dynamics of LULCC in Indonesia between 2003 and 2023 using remote sensing and geographic information systems/science (GISci) and explored knowledge gaps in agricultural land conversions and the impact of food security programs such as the Food Estate Program. This study employed the Moderate Resolution Imaging Spectroradiometer (MODIS) MCD12Q1 land cover data available through Google Earth Engine, and classified land cover changes into four dominant categories: forest land, mixed vegetation, agricultural land, and urban land. Utilizing transition matrix analysis and cartographic visualization, this study identified LULCC trends in forest, urban, and agriculture land conversions across Indonesia. It was estimated that Indonesia’s urban land increased by nearly 1,500 km² over the study period, primarily in the form of agricultural land conversions, particularly on Java Island. Although agricultural land experienced a net loss of around 10,000 km², significant expansions were observed in regions outside Java, particularly in Sumatra, Kalimantan, and Food Estate Program locations. Forest land declined by more than 61,000 km², with more than 99% of the forest land converting mainly into mixed vegetation, indicating potential large-scale deforestation. However, nearly 88,000 km² of mixed vegetation reverted to forest land, suggesting potential reforestation or regrowth in specific regions. Considering these transitions, this study also addresses challenges associated with land use classifications and the likelihood of errors of omission and errors of commission occurring on an interannual basis. Furthermore, the study further discussed key environmental concerns linked to land use policy, including the Food Estate Program, large-scale coal mining, and extensive oil palm plantations, which have contributed to deforestation, land degradation, potential food security issues, and other challenges. Ultimately, this study provides insights into comprehensive long-term and large-scale LULCC dynamics, which if understood are a key to more effective land management policy and sustainable land use planning and conservation efforts in Indonesia
Effect of Traditional versus Fenceline Weaning on Lamb Stress
Get PDFStress is a significant factor affecting the health, behavior, and performance of sheep in production settings. Most lambs go through artificial weaning, and this is a stressful time in a lamb’s life. Stress can negatively affect growth rates, feed efficiency, and susceptibility to illness and parasites. The traditional and most common method of weaning is the abrupt separation of lambs from their dams. An alternative method of weaning, fenceline weaning, has been found to reduce stress in cattle and may also reduce stress in sheep. The objectives of this study were to evaluate body weights, fecal egg counts, and behavior to determine if the traditional or fenceline weaning method has lower stress associated with weaning in lambs. The study was conducted at the Milo J. Shult Agricultural Research & Extension Center, with two 14-day trials, totaling 32 majority Hampshire breed lambs. Lambs were assigned to either a fenceline or abrupt weaning group. Body weights were recorded on days 0, 7, and 14, and fecal samples were collected on days 0 and 14 to assess parasite loads. Behavioral responses were observed through video recordings using instantaneous scan sampling for the first three days after weaning. Fecal egg counts and weight change measurements were not different (P ≥ 0.26) between the weaning methods. The interaction between weaning group and day was detected for lying and eating behaviors (P ≤ 0.02). The lambs in the fenceline weaning group performed standing and walking behaviors less frequently than the abrupt weaning group. This indicates that the fenceline weaned group had less stress than the abruptly separated weaning group. Mitigating stress is important in finding the best management practices to improve animal welfare and productivity
Device for Ambient Thermal and Vibration Energy Harvesting
No full textAn integrated circuit on a chip may include a plurality of capacitors that are connected in series and generate an AC noise signal. A selected bandwidth of the AC noise signal transmits through the series of capacitors as a first AC power signal. Respective rectifiers are positioned for receiving a positive cycle of the first AC power signal and a negative cycle of the first AC power signal. Output terminals are connected to the respective rectifiers and configured for connection to an off chip circuit. The capacitors may be fixed or variable gap capacitors
Respiratory Compensated Robot for Liver Cancer Treatment
No full textA robotic platform system having a lower stage with a motorized cartesian carriage, an upper stage, and a needle insertion module that connects both stages together
