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NICKEL SUPERALLOY COMPOSITION AND PROCESS OPTIMIZATION FOR IMPROVED WELDABILITY
Get PDFIn order to improve the efficiency of advanced ultra-supercritical power plants, materials must be designed to maintain mechanical properties in high pressure and high temperature environments. Nickel superalloys are a viable option, but are expensive and are difficult to weld, leading to joint failures. The goal of this project is to experimentally evaluate computationally-designed nickel superalloys for increased weldability and decreased alloy cost, while maintaining mechanical properties. Two optimized nickel alloys were designed to these targets and compared to benchmark nickel superalloys. Both optimized alloys had lower cost, with a 5Co-4Ti alloy exceeding room temperature hardness and elastic modulus values, but with increased solidification cracking susceptibility. The 7Co-3Ti alloy maintained elastic modulus values and room temperature hardness, and had increased strain-age cracking resistance
ENERGY EQUITY IN INDIA’S RENEWABLE ENERGY TRANSITION: A POLICY DESIGN AGENDA
Get PDFIndia’s transition to renewable energy has prioritized large-scale, grid-based electrification, often overlooking energy equity, particularly in rural communities. Many households would benefit more from decentralized solutions than from grid extension, yet current policies neither guarantee equitable access nor address pre-existing social and economic inequalities in energy distribution. This dissertation examines the sensitivity of India’s renewable energy policies to energy equity, with a specific focus on gender equity in rural last-mile connectivity. The study is guided by the fundamental question: How can implementation of solar energy program alleviate the lives of rural communities? Using a mixed-method approach that combines policy analysis with an ethnographic case study of a community solar program in Jharkhand, this research investigates the impact of small-scale solar home lighting systems (SHLS) on energy access and gender equity. The findings suggest that SHLS can mitigate gendered disparities in energy access, but only within a policy environment that incentivizes NGOs to implement community-scale programs. This research emphasizes the need for Indian energy policy to integrate equity and justice by fostering effective collaboration between state and non-state actors. Additionally, it highlights how cultural and social identities such as gender, ethnicity, and economic class shape access to energy services. By prioritizing energy equity in policy planning, strengthening NGO-government coordination, and addressing gender disparities, this dissertation offers insights for advancing a just and inclusive energy transition
Multiple testing correction for mean tests in time series rolling window analysis with an application of GWAS methods
No full textRolling window analysis is a popular tool in time series research. However, conducting hypothesis tests on all rolling windows simultaneously introduces a multiple testing problem. In the literature, bootstrapping the maximum of all statistics from rolling windows is the most commonly used, if not the only, method to address this issue. This paper seeks to provide a simpler and faster alternative to bootstrap methods by adapting p-value combination techniques that are popular in genome-wide association studies to the context of mean tests in a time series rolling window analysis. Some p-value combination methods in genetics require knowledge of the correlation structure of test statistics, which can typically be obtained from external sources. However, such information is often unavailable for time series datasets. To address this challenge, we employ the autoregressive sieve approach, which allows for the computation of correlation structures based on estimated autoregressive coefficients. We present finite sample simulations to illustrate the performance of p-value combination methods in a rolling window setting and offer recommendations for practitioners and future researchers in this area
The Effect of Sc and Zr Dispersoids on the Final Properties of a 6xxx Series Extrusion Alloy
No full textThe 6xxx-series aluminum alloys are used for automotive production due to their high specific strength and ability to be manufactured into complex shapes via extrusion or stamping. Small additions of Cr and Mn are dispersoid formers added to improve recrystallization resistance and decrease peripheral coarse grain growth during extrusion. Replacing Cr and Mn with Sc and Zr maintains the recrystallization resistance while decreasing peripheral coarse grain volume, which increases the yield strength and ultimate tensile strength while maintaining ductility in a peak-aged extrusion
Friendship through a narcissistic lens: The role of narcissism in perceived humor similarity among friends in Germany and the US
Get PDFTheoretical perspectives on how narcissism functions in social relationships suggest that narcissistic individuals may either enhance or devalue their close others. On the one hand, because close others are generally perceived as similar to oneself, narcissists may project their own grandiosity onto them, thereby enhancing their characteristics. On the other hand, narcissists strive for uniqueness and superiority, which may lead them to devalue their close others in comparison to themselves (self-enhancement). These conflicting assumptions about the role of narcissism in social relationships have yet to be directly tested. The present study examines how narcissism relates to perceived similarity and the tendency to enhance close friends versus self-enhance over them. Using humor styles as a socially relevant indicator variable, we analyzed self- and friend-reports in samples from Germany and the United States. Our findings indicate that although individuals generally perceive themselves as similar to their friends, higher levels of narcissism are associated with lower perceived similarity. Furthermore, latent change score modeling partially supported the hypotheses that grandiose narcissism is linked to self-enhancement over close friends in adaptive humor styles, whereas vulnerable narcissism is associated with self-enhancement in maladaptive humor styles
ThermalTrack Dataset- Training Images- Fused RGB LWIR- sequence 6
Get PDFWe present a wheel track detection system that leverages RGB- Thermal (RGB-T) imaging, where thermal channels reveal critical temperature differentials between compacted tracks and loose snow- tracks exhibit higher thermal inertia and lower reflectivity, emitting stronger radiation signatures even in visually homogeneous conditions. By fusing these distinctive thermal patterns with RGB spatial information, our method reliably identifies navigable tracks, enabling robust path-following in complete white-out conditions where snow textures and terrain features become indistinguishable
Review of Geologic Hydrogen
Get PDFThis report reviews geologic (white) hydrogen systems, focusing on their generation mechanisms, detection methods, global distribution, and field-scale validation challenges. Unlike industrial hydrogen, geologic hydrogen forms abiotically through processes like serpentinization, radiolysis, mantle degassing, and mineral deformation. Historical seeps have been reported since the 19th century across Europe, Australia, Africa, and the Americas, with Mali’s Bourakebougou field being the only known self-recharging reservoir. Detection techniques such as soil gas surveys, borehole logging, geophysics, and remote sensing are evaluated, alongside complicating factors like microbial oxidation, soil variability, seasonal cycles, and anthropogenic artifacts. A 2024 soil gas survey along the Keweenaw Fault in Michigan serves as a case study. Despite calibration errors affecting absolute concentration, the campaign reveals valuable insights into methodological improvements and geologic favorability. The report underscores the need for systematic exploration and interdisciplinary collaboration in advancing this emerging field of clean energy
PROCESS TO DESIGN AND ANALYZE DYNAMIC ENVIRONMENT TEST FIXTURES (PDADYE)
Get PDFVibration qualification testing is an important requirement in many industries. In-lab testing is intended to evaluate a component’s life expectancy by exposing it to a dynamic environment similar to what it may experience in its field condition. To successfully perform these tests, it is imperative that the field boundary conditions (BCs) of the component of interest are replicated as closely as possible in the lab. One approach to achieving accurate dynamic environment testing is to design a fixture that sufficiently represents the impedance of the next-structure (field structure). The process to design and analyze dynamic environment test fixtures (PDADyE) is a method created to guide users through the process of developing a vibration test fixture that accurately reproduces the components field BCs. These BCs can consist of multiple directions of excitation and attachment locations between the component of interest and its field structure.
The process has been applied to the Boundary Condition Challenge problem and the Box Assembly with Removable Component (BARC) hardware and modified versions thereof. A dynamic fixture was designed, verified, and manufactured for 3 different cases, (1) a one-attachment translation case, (2) a two-attachment translation case, and (3) a two-attachment translation and rotation case.
Throughout the development of these fixture designs and the design process, many primary structure and tuned absorber designs were explored to introduce additional resonances into the dynamic test fixtures with the goal of reproducing the field BCs in the lab
Additive manufacturing of zinc-based biomaterials: Fabrication, performance and property evaluation
Get PDFThe use of zinc and its alloys in additive manufacturing has become an important focus in interventional medical field. This is because zinc as an implant is naturally degradable, has solid mechanical characteristics, and is biocompatible. Biodegradable Zn-based metals made with additive manufacturing offer significant advantages in creating personalized medical implants. This review aims to provide an overview of different types of additive manufacturing methods and processes that can be used in the fabrication of Zn-based medical implants. It offers a comprehensive understanding of additive-manufactured Zn-based alloys for interventional surgeries. The study also summarizes the relationships between degradation properties, mechanical properties, antibacterial activity, and biocompatibility of additive-manufactured Zn-based biomaterials prepared via different fabrication techniques. Additionally, the review analyses various strategies for overcoming core challenges associated with Zn-based medical implants prepared by additive manufacturing. Finally, the review also proposes future directions for addressing biodegradability and biocompatibility in additive-manufactured Zn-based materials for scaffolding and orthopaedic implant applications. Overall, this study serves as a foundation for future research into the design of biodegradable Zn-based alloys, specifically for tissue scaffolding and bone repairs, and provides insights into their clinical prospects
