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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Mechanochemical synthesis of hydraulically reactive calcium silicate minerals via thermally-assisted mechanical grinding

This study explores a thermally assisted mechanochemical approach alternative to conventional cement synthesis as a potential to produce hydraulically reactive calcium silicate phases. Ball milling of mixed CaO/SiO 2 feedstocks at temperature ranges 100-300 °C increases the formation of the Ca-O-Si bonds and precursor reactivity. Spectroscopic analyses (FTIR, MAS-NMR, UV-Vis DRS) indicate increasing amorphization with milling temperature, attributed to improved mixing and thermally assisted diffusion. Upon hydration, all treated samples exhibit exothermic heat release, with the sample prepared at 300 °C showing the most pronounced reactivity. Thermal analysis reveals weight loss consistent with C-S-H formation, confirming cement-like behavior. In summary, moderate thermal input during milling promotes structural activation and enhances downstream hydraulic reactivity, providing a proof-of-concept for energy-reduced cement precursor processing.

Alite↗
DOE OSTI2025

GRinding Automated Classification Engine

This work is an ML-driven framework for automated surface analysis of microscopy images. We create a training dataset by imaging stainless steel samples to benchmark four developed deep neural network architectures. These models, based on a YOLOv8n-cls backend, integrate image features and process metadata using various fusion methods to distinguish between acceptable and unacceptable surface finishes. This code is associated with publication "Classifying Alloy Surface Preparation Quality with Metadata-Infused Machine Learning for Rapid Alloy Discovery" for project APEX LDRD-ER (25-ERD-039)

Gongora, AldairE [Lawrence Livermore National Labo↗
DOE OSTI2013

Grinding Energy, Underground

The amount of electricity required to power a crusher and grinder used at an underground mine. To access the model referenced in the report, please visit https://www.netl.doe.gov/energy-analysis/details?id=2D2F3A49-D5F9-4307-A827-BAA46F2C789D

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Enhancing CO 2 Mineralization Rate and Extent of Iron and Steel Slag via Grinding

Roughly 10% of the CO 2 emissions from iron and steel making are attributable to the direct release of CO 2 from the thermal decomposition of carbonates to produce flux, mainly CaO, used for impurity removal. Notably, these direct emissions remain even if carbon-based steelmaking is replaced by hydrogen-based steelmaking. After removing impurities from the molten metal, this flux becomes the solid waste product called ‘slag’, a primarily Ca-silicate material. The transformation of slag back into carbonates is thermodynamically spontaneous with negative ΔG in the ambient environment, meaning that ~10% of the CO 2 emissions from iron and steel making could be negated if equipment and methods were developed to support CO 2 mineralization. However, the rate of CO 2 mineralization using slag is slowed by several environmental, geometric, and processing factors. We leverage an experimentally verified model of CO 2 mineralization to determine how to efficiently accelerate the process. Increasing the crystallinity of slag, increasing the relative humidity, and reducing the grain size of slag particles provide the greatest increase in CO 2 mineralization rate at the lowest energy penalty. Increasing the concentration of CO 2 and the temperature provide only modest increases in the CO 2 mineralization rate while incurring a substantial energy penalty. For steelmaking slags, CO 2 mineralization represents low-hanging fruit as the current reuse pathways are low value. For ironmaking slag, replacing the production of amorphous slag for the cement industry with the production of crystalline slag for CO 2 mineralization becomes financially preferable when a carbon price/tax exceeds 67.40 USD/t-CO 2 .

42 ENGINEERING↗
DOE OSTI2023

Grinding and Pelleting Characteristics of Municipal Solid Waste Fractions

The efficient utilization of low-cost carbon feedstocks, such as municipal solid waste (MSW), in biorefineries has become increasingly important for reducing GHG emissions and meeting the growing demand for renewable energy sources. However, MSW as a feedstock presents several challenges, including high moisture content, compositional variability, particle size and shape, density, and ash content. To address these challenges, the potential of mechanical dewatering and high-moisture pelleting processes for densifying MSW fractions, such as paper, cardboard, thin plastic, and thick plastic, into low-cost carbon feedstocks with improved handling and conversion properties were investigated. The effect of these preprocessing technologies on the critical quality attributes (CQAs) of the resulting pellets, including bulk density, durability, and size uniformity, were evaluated. The results showed that with these preprocessing technologies, the paper and cardboard fractions could be pelleted at moisture contents over 40% (w.b.) while achieving >99% durability and >300 kg/m3, while the high moisture plastic fractions were not suitable for pelleting. The thick plastic fraction processed in a screw press was shown to remove up to 30% of the moisture content in a single pass. These findings suggest that these mechanical preprocessing technologies can improve the physical properties of low-cost municipal solid waste fractions for biofuels production.

09 BIOMASS FUELS↗
DOE OSTI2024

Collapsar Gamma-Ray Bursts Grind Their Black Hole Spins to a Halt

Abstract The spin of a newly formed black hole (BH) at the center of a massive star evolves from its natal value due to two competing processes: accretion of gas angular momentum that increases the spin and extraction of BH angular momentum by outflows that decreases the spin. Ultimately, the final, equilibrium spin is set by a balance between both processes. In order for the BH to launch relativistic jets and power aγ-ray burst (GRB), the BH magnetic field needs to be dynamically important. Thus, we consider the case of a magnetically arrested disk (MAD) driving the spin evolution of the BH. By applying the semianalytic MAD BH spin evolution model of Lowell et al. to collapsars, we show that if the BH accretes ∼20% of its initial mass, its dimensionless spin inevitably reaches small values,a≲ 0.2. For such spins, and for mass accretion rates inferred from collapsar simulations, we show that our semianalytic model reproduces the energetics of typical GRB jets,L jet ∼ 10 50 erg s −1 . We show that our semianalytic model reproduces the nearly constant power of typical GRB jets. If the MAD onset is delayed, this allows powerful jets at the high end of the GRB luminosity distribution,L jet ∼ 10 52 erg s −1 , but the final spin remains low,a≲ 0.3. These results are consistent with the low spins inferred from gravitational wave detections of binary BH mergers. In a companion paper by Gottlieb et al., we use GRB observations to constrain the natal BH spin to bea≃ 0.2.

Astronomy & Astrophysics↗
NASA NTRS1980

Grinding and polishing articles in bulk: Burnishing

Various processes and equipment used for burnishing different materials are discussed. Drum and vibration installations are considered, as are processing chemicals and additive materials used in the burnishing process.

Schmotz, K.↗
NASA NTRS1983

Air-jet milling of grinding materials

The principles of air-jet milling of fine powders and the influence of air pressure and milling intensity are discussed. Impact, abrasion, and resultant grain shape are also considered.

Wozniak, K.↗
NASA NTRS1993

Tool grinding and spark testing

The objectives were the following: (1) to revive the neglected art of metal-sparking; (2) to promote quality-assurance in the workplace; (3) to avoid spark-ignited explosions of dusts or volatiles; (4) to facilitate the salvage of scrap metals; and (5) to summarize important references.

Widener, Edward L.↗
NASA NTRS1993

Deviations from the straight line: Bumps (and grinds) in the collisionally evolved size distribution of asteroids

Dohnanyi established that the size distribution of a collisionally relaxed population is a power-law with a -3.5 slope (incremental diameter), provided that: (1) collisional parameters are independent of size and (2) there is no lower limit on the population size for shattering impacts. In the course of studying collisional effects over a wide range of asteroid sizes (cm up to hundreds of km range), we have investigated the consequences of relaxing the second condition, while maintaining the first one.

Davis, D. R.↗
NASA NTRS2012

Employing a Grinding Technology to Assess the Microbial Density for Encapsulated Organisms

Projects that utilize large volumes of nonmetallic materials of planetary protection concern pose a challenge to their bioburden budget, as the most conservative value of 30 spores/cubic cm is typically used. The standard laboratory procedures do not provide any direction into the methodologies to understand the embedded bioburden within such nonmetallic components such as adhesives, insulation, or paint. A tailored, novel, destructive hardware technology employing a household box grater was developed to assess the embedded bioburden within the adhesives, insulation, and paint for the Mars Science Laboratory (MSL) project.

Benardini, James N.↗