Mines Repository (Colorado School of Mines)
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Nevada Porphyry Mines, Inc., Round Mountain, Nevada
No full textMine report no. 1995.Typescript (carbon copy).Nevada Porphyry Mines, Inc., Round Mountain, Nevada -- Vertical section through No. 2 shaft, Nevada Porphyry Mines, Inc. -- Zone assay plan showing crosscut assay averages and Glory Hole production, Nevada Porphyry Mines, Inc
Effects of nitrogen, ferrite morphology, and texture evolution on impact toughness in heat-affected zone simulations of V-microalloyed HSLA steel welds
No full textIncludes bibliographical references.2025 Spring.Microalloyed HSLA steels are used in lower-operating temperature structural applications, including bridges and pipelines, due to the wide range of achievable strength and toughness values obtained in the as-rolled products. However, the low temperature toughness associated with welds in high-impact applications remains an opportunity for improvement due to the tendency to form lower-toughness microconstituents such as bainite. Acicular ferrite (AF) is being investigated as a microconstituent to improve low temperature impact toughness in the coarse-grained heat affected zone of welds while maintaining required tensile strength levels for such applications. In this study, peak temperature and cooling rate were varied to simulate different HAZ regions in two experimental V-microalloyed steels differing in N content to produce microstructures with various ferritic microconstituents. Two alloys of different N contents of 80 and 200 ppm were utilized to change the volume fraction of VN precipitates in the microstructure. Optical microscopy and crystallographic analysis using EBSD were utilized to differentiate between the ferritic microconstituents and quantify microstructural evolution with processing parameters.
A shift from primary ferrite to martensite/bainite microstructures was observed with increasing cooling rate at both peak temperatures selected for continuous cooling behavior analysis. Greater N content was associated with more grain-boundary ferrite. Crystallographic analysis further supported a shift towards a more displacive nature of the developed ferrite microconstituent with increasing cooling rate. The hardness increased as cooling rate increased due to less primary ferrite, with the alloy containing more N producing greater hardness values in all conditions as a result of grain refinement and a higher fraction of high dislocation density microconstituents, such as bainite. A higher N content produced finer prior-austenite grains at every cooling rate, yielding greater amounts of grain-boundary ferrite morphologies. Charpy impact toughness at -20 °C increased as cooling rate increased for both alloys in AF-predominant conditions due to the reduction in grain-boundary ferrite amount and effective ferrite grain size. A lower N content was associated with enhanced low-temperature toughness at every cooling rate due to less grain-boundary ferrite
Reconstruction of a genome-scale metabolic model for Auxenochlorella protothecoides
No full textIncludes bibliographical references.2025 Spring.Microalgae show strong potential as alternative energy platforms for biofuel production and high-value product synthesis, yet the complexity of photosynthetic metabolism has posed significant modeling and engineering challenges. Recent developments in genome-scale metabolic models (GEMs) have substantially advanced our understanding of microalgal biology by integrating omics data, improving light-harvesting simulations, and automating large portions of the reconstruction process. Building upon these methodological gains, a new GEM iPro4643 was reconstructed for Auxenochlorella protothecoides, capturing the organism’s metabolic versatility under autotrophic, mixotrophic, and heterotrophic conditions. This model highlights both shared pathways with other algal species and features such as rapid heterotrophic growth and energy storage dynamics that are especially relevant to industrial-scale applications. Additionally, an in-depth 13C metabolic flux analysis (MFA) of heterotrophically grown A. protothecoides reveals that actual carbon flux is similar to that predicted by the model while diverging from model predictions optimized strictly for growth, pointing to an underestimation of flux toward starch. These findings underscore the need for objective functions and modeling frameworks that incorporate energy storage and regulatory constraints, particularly under fluctuating environmental conditions. By uniting insights from state-of-the-art GEM methodologies, a refined and experimentally validated metabolic model, and empirical MFA data, this body of work paves the way for more accurate predictive capabilities and targeted metabolic engineering strategies aimed at enhancing lipid productivity and other commercially valuable bioproducts in microalgae
Report of Copper Queen group of claims on Mount Alcott, Yellow Pine mining district, Clark County, Nevada
No full textMine report no. 1772.Typescript (carbon copy)
Luckie 2 and adjacent mines
No full textPhotocopy; blue line."Traced Apr. 7-11, 1927 by Henry A. Drumm, Maps, Boulder, Colorado."Updated in pencil; no date.Coordinates: (North 40.005°, West 105.4306°)6th Meridian, 1N-72W-36Scale 1:600. 1 inch = 50 feet.Covers parts of Boulder County, Colorado. Covers parts of the Gold Hill quadrangle, Colorado. Commodities mined: tungsten and gold
Complex thermoelectric transport in bismuth-antimony alloys
No full textIncludes bibliographical references.2025 Spring.Bi1−xSbx alloys are classic thermoelectric materials for near-cryogenic applications. Despite more than half a century of study, unraveling the underlying transport physics within this space has been nontrivial due to the complex electronic structure, disorder, and small band gap within these alloys. Further, as Peltier coolers, Bi1−xSbx alloys operate in a bipolar regime; as such, understanding the impact of minority carriers is critical for further improvements in device performance. This study unites first principles calculations with low-temperature experimental measurements to create a generalized model for transport within semiconducting Bi-Sb alloys. Our exploration reveals the interplay between the complex, degenerate valence band structure with the extremely light conduction bands. By building a hybrid
computational/experimental model, an understanding of both the electron and hole relaxation times emerges both as a function of temperature and energy. Special quasi-random supercell calculations reveal that, despite significant atomic disorder, the electronic band structures within the alloy remains largely unaffected and electron-phonon scattering dominates. For charge carriers near the band edges, the relaxation times are thus extremely long, consistent with cyclotronic behavior appearing at low magnetic fields (≪1 T). Modeling thermoelectric performance suggests that the valence band edge deformation potential is significantly weaker and highlights the potential for p-type compositions to meet or exceed the current n-type alloys
Geological report on properties of American Smelting & Refining Company, Sierra Mojada, Coahuila, Mexico
No full textMine report no. 2022.Includes illustrations and maps.Typescript (carbon copy).Geological report on properties of American Smelting & Refining Company, Sierra Mojada, Coahuila, Mexico -- Preliminary letter on areas: (1) north of Oriental and Fronteriza claims; (2) between Sierra Mojada & San Francisco mines; (3) of Palomas Negras mining district -- Plates A-D
Notes on graphite
No full textMine report no. 1948.Two copies of report; copy 1 includes correspondence.Typescript (carbon copy)
Viscoelastic response and deformation mechanics of polymeric foams under cyclic compression
No full textIncludes bibliographical references.2025 Spring.Flexible polymeric foams are widely used in energy absorption applications, from protective gear to engineered structural components, yet their response to cyclic compressive loading remains poorly understood. This study investigates the viscoelastic behavior and fatigue mechanisms of polyurethane and silicone foams under intermediate strain-rate cyclic compression using a combination of advanced experimental techniques, including dynamic mechanical analysis (DMA) with Fourier transform rheology (FTR) and in-situ computed tomography (CT) imaging. Experiments on open-cell polyurethane foams reveal that stiffness and damping decline over cyclic loading, with degradation rates strongly influenced by material chemistry and strain rate. High-resolution CT imaging further uncovers that deformation is driven by pore collapse and structural instabilities rather than changes in cellular geometry. Statistical analysis supports these findings. Extending these methods to additively manufactured open-cell silicone lattice foams, the study identifies comparable trends in stiffness decay, with a direct correlation between viscoelastic nonlinearity and fatigue behavior across different pore structures and strain rates. The findings advance our understanding of how foam microstructure and loading conditions interact to influence long-term mechanical performance. By connecting viscoelastic response with deformation mechanisms, this work establishes a framework for designing durable, energy-absorbing materials tailored for applications requiring reliable performance under repetitive loading