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At least 55 records · Page 3

Study of application of ERTS-A imagery to fracture-related mine safety hazards in the coal mining industry

The author has identified the following significant results. The mine refuse inventory maps were prepared in response to a need by both the State and the coal industry. The lack of information on the scope of the problem handicapped all people concerned in drafting realistic legislation for a severance tax on coal production to raise funds for restoration of refuse sites. The inventory was conducted rapidly and economically, and demonstrated the benefits which can be derived through remote sensing methods.

Wier, C. E.↗

Innovation for Pollution Control

Kinetic Controls Inc.'s refuse-fired steam generating facility led to the development of an air pollution equipment control device. The device is currently marketed by two NASA/Langley Research Center employees. It automatically senses and compensates for the changes in smoke composition when refuse is used as a fuel by adjusting the precipitator's voltage and current to permit maximum collection of electrically charged dust particles. The control adapts to any electrostatic precipitator and should have extensive commercial applications.

Source record↗

Profit from a Problem

The Refuse-fired Steam Generating Facility was jointly sponsored by Hampton, NASA Langley and Langley Air Force Base. The facility disposes of all solid waste from the NASA Center, the Air Force Base, the Army's Fort Monroe and other federal installations in the area, and accommodates about 70 percent of Hampton's municipal waste. Incinerated refuse is reduced to a readily-disposable ash whose volume is one-seventh that of the solid waste brought to the plant. The energy produced in the burning process is converted to steam for use in research and administrative facilities at Langley Research Center. Plant is expected to produce some 300 million pounds of steam annually, about 85 percent of Langley Research Center's needs.

Source record↗

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

NASA Center KSC↗

Pilot Scale Testing of Lignite Adsorption Capability and the Benefits for the Recovery of Rare Earth Elements from Dilute Leach Solutions

Naturally occurring organic materials containing humic acids show a strong affinity towards rare earth elements (REE) and other critical elements. Leaching experiments on lignite coal waste produced from construction sand production revealed that the contained REEs were associated with the organic matter. Furthermore, adsorption studies revealed that the lignite waste was capable of extracting REEs from a model solution and increased the REE content of the lignite waste by more than 100%. As such, this study aimed to utilize the lignite waste to adsorb REEs from pregnant leach solutions and acid mine drainage sources having low REE concentrations and subsequently leach the lignite material to produce pregnant leach solutions containing relatively high amounts of REEs, which benefits the performance and economic viability of downstream separation and purification processes. An integrated flowsheet was developed based on this concept and tested at a pilot scale. The pregnant leachate solution (PLS) was generated from a heap leach pad containing 2000 tons of Baker seam coarse refuse. The pilot scale circuit was comprised of aluminum precipitation, adsorption using the waste lignite, and rare earth-critical metal (RE-CM) precipitation stages in succession. The results indicated that the aluminum precipitation stage removed over 88% and 99% of the Al and Fe, respectively. The adsorption stage increased the REE content associated with the waste lignite from 457 ppm to 1065 ppm on a whole mass basis. Furthermore, the heavy REE (HREE) content in the feedstock increased by approximately 250%, which raised the percentage of HREE in the REE distribution by 19 absolute percentage points. In addition to the REEs, concentrations of other critical elements such as Mn, Ni, and Zn also improved by 75%, 37%, and 250%, respectively. Bench-scale tests revealed that increasing the solids concentration in the waste lignite and PLS mix from 1% to 20% by weight enhanced the adsorption efficiency from 32.0% to 99.5%, respectively. As such, a new flowsheet was proposed which provides significantly higher REE concentrations in the PLS that can be fed directly to solvent extraction and/or oxalic acid precipitation and, thereby, enhancing process efficiency and economics.

58 GEOSCIENCES↗

Rapid characterization of MSW and RDF feedstocks for waste-to-energy process using LIBS and ML techniques

The heterogeneity in the composition of municipal solid wastes (MSW) poses significant challenges in the production of biofuel and bioproducts. This research aims to enhance the accuracy and efficiency of waste analysis and characterization by introducing a fast characterization approach for MSW-derived refuse-derived fuels (RDF) by combining Laser-Induced Breakdown Spectroscopy (LIBS) with advanced machine learning (ML) techniques. The approach combines data pre-processing of LIBS spectra of RDF, and the development of ML models trained on domain and theory-based spectral features for predicting process parameters. These models are adept at predicting key process parameters like High Heating Value (HHV), carbon content, and volatile matter. This approach can achieve an average RRMSE of 2.13% and R 2 of 0.98 or higher for all considered parameters on testing data. This work demonstrates significant potential for improving waste sorting, processing efficiency, and environmental compliance over traditional labor- and time-intensive laboratory waste analysis and characterization.

09 BIOMASS FUELS↗

Natural Gas Vehicle Basics

Natural gas powers about 175,000 U.S. vehicles and more than 23 million vehicles worldwide [1]. Natural gas vehicles (NGVs) are a good choice for high-mileage (high fuel-use) fleets - such as buses, medium- and heavy-duty trucks, and refuse vehicles - that are centrally fueled or operate within a limited area or along a route with natural gas fueling stations. The advantages of natural gas as an alternative fuel include its domestic production, established distribution network, relatively low cost, and emissions benefits.

30 DIRECT ENERGY CONVERSION↗

A review study of rare Earth, Cobalt, Lithium, and Manganese in Coal-based sources and process development for their recovery

The world’s majority predominantly relies on foreign sources for supplying critical minerals. This renders the countries susceptible to supply chain disruption and urges them to develop alternative sources to compete in technological advancements. Among many proven newly identified sources, coal and coal-based materials present their opportunities. Due to the complex structure of coal, many mineral forms can be found in coal-related sources, including critical element-containing minerals. Among the fifty critical elements and minerals defined by the USGS, the rare earth elements, cobalt, lithium, and manganese, are particularly significant as they have enormous importance in high-technology product development. These critical metals can be found in high concentrations in coal-derived sources, such as coal refuse, coal combustion products, and coal acid mine drainage, and be recovered through various separation techniques. Further, this study aims to advance the understanding of these elements' extraction and commercial potential from coal and coal-related sources and help address the world's challenges in the critical mineral supply chain. The concentrations and occurrences of these four commodities in coal-related sources were first reviewed. Later, their recovery processes were discussed, and a conceptual process flowsheet was proposed to selectively recover the rare earth elements, lithium, cobalt, and manganese from coal-based sources.

58 GEOSCIENCES↗

Hydrogen Production from Polyethylene Pyrolysis

Hydrogen is anticipated to play a pivotal role in the future of clean energy and decarbonization efforts, serving as an energy storage medium, a power generation source, and a clean fuel for transportation. While most hydrogen is produced from carbonaceous fossil feedstocks like natural gas, petroleum, and coal, there is growing interest in using refuse-derived fuels such as waste plastics and municipal solid waste (MSW) as alternative feedstocks. Thermochemical processes such as pyrolysis and catalytic cracking can convert nonrecyclable plastics and organic MSW components to produce hydrogen with lower life cycle greenhouse gas emissions when coupled with CO 2 capture. Such approaches not only address waste-management challenges but also reduce methane emissions from landfills. Furthermore, waste feedstocks are low cost and can support meeting demands for hydrogen across various industries. In this work we examined production of hydrogen from high-density polyethylene (HDPE) as a model polymer using pyrolysis. Analytical studies of pyrolysis utilizing gas chromatography–mass spectrometry (GC/MS) provide insights into conversion pathways for plastic waste, potentially reducing the environmental footprint of traditional hydrogen production methods. This work generates a baseline methodology for hydrogen production from plastic pyrolysis with and without a catalyst and the necessary product distribution baseline from key single plastics. The effect of pyrolysis temperature on the conversion of HDPE was evaluated both with and without a catalyst(s), and the product distributions measured via GC/MS were identified and hydrogen formation was quantified. These results will help guide future research efforts to optimize catalysts and processes for more efficient hydrogen production and mixed plastic waste management.

Catalysts↗

Metal–bicarbonate ion pairing in alkaline aqueous solutions from multilevel embedded correlated wavefunction theory and molecular dynamics

In this work, we examine ion-pairing mechanisms of bicarbonates in alkaline aqueous solutions with the divalent metal ions most abundantly present in seawater, namely, Ca 2+ and Mg 2+ . We employ a rare-event enhanced sampling approach within first-principles molecular dynamics to explore regions of phase space spanning solvent-shared to contact ion pairs. Second-order Møller–Plesset perturbation theory (MP2) corrections are subsequently applied in an embedding framework (EMB) to refine the electronic structure of stationary states and associated reaction barriers along the free-energy profiles while retaining the extended solvent effects at the density functional theory (DFT) level. Ca 2+ –HCO 3 − was previously hypothesized to exist in a solvent-shared ion pair (SSHIP) by DFT studies with an endergonic contact ion pair (CIP) formation; however, our EMB-MP2 refinement of the DFT ion-pairing pathways reveals that Ca 2+ and HCO 3 − form a virtually barrier-free CIP in alkaline solutions, with even more energetic ease than the widely studied Ca–CO 3 ion pair. We find qualitative agreement between DFT and EMB-MP2 for Mg 2+ —unlike Ca 2+ , Mg 2+ refuses to shed its strong hydration shell, thereby preferring a SSHIP state with a significant activation barrier to crossover to the CIP forms—a trait reminiscent of ion pairing in Mg–CO 3 and closely related to the kinetic limitations underlying the famous subject of the dolomite problem. Our study highlights the importance of improved electronic structure descriptions of liquids, modeled as a condensed phase of matter lacking in long-range crystalline order. It also strongly suggests that Ca 2+ –HCO 3 − CIPs are likely precursors involved in prenucleation of CaCO 3 mineral formation in seawater.

Sharma, Vidushi [Princeton Plasma Physics Laborato↗

When One Cannot Bypass the Byproducts: Plastic Packaging Waste Embedded in Production and Export

While packaging is praised for reducing waste of perishable food products, packaging waste is a growing concern. Its least recyclable type, plastics waste, is increasingly polluting the marine environment and many developing countries are now refusing to take the waste from developed countries. Before responsibility can be established, one has to identify the key producers and consumers. This paper adjusts the packaging waste satellite account in EXIOBASE 3 by combining the official waste data published by the World Bank. Based on input-output methods, we find that the world's top suppliers of plastic packaging waste are the United States, China, and Brazil. Food and beverage products constitute the bulk of the problem. Yet, 21% of these countries' plastic packaging waste is induced export. At the global level, it is 25.8%. About 76.0% of export-induced plastic packaging waste corresponds to packaging of the exported goods that will ultimately be disposed of in the destination country; while the others correspond to the packaging used in their supply-chain and wasted domestically. We conclude that international efforts need to assign shared responsibility and promote improvement in plastic packaging recyclability.

environment responsibility↗

Rheological Properties of Enzymatically Hydrolyzed Corn Stover Pretreated via Deacetylation and Mechanical Refining

Lignocellulosic biomass is a feedstock for fuels and chemicals that does not compete with food resources and has less contaminants than refuse-derived biomass feedstocks. To convert lignocellulosics to biofuels or value-added products, multiple processing steps are typically necessary. One method of producing biofuels from lignocellulosic biomass utilizes a deacetylation and mechanical refining pretreatment and an enzymatic hydrolysis reaction to produce fermentable sugars from cellulose and hemicellulose. The rheological properties of biomass, such as yield stress and plastic viscosity, change during enzymatic hydrolysis and alter the energy requirements for pumping and mixing, an important consideration for the design of processing equipment. The dynamic changes in rheological properties that occur in a corn stover feedstock undergoing enzymatic hydrolysis are characterized in this work, and the influence on pressure losses in piping systems is estimated. Two rheometer geometries were fabricated with stereolithography 3D printing to reduce wall slip and sample ejection. The slurries have complex rheological behaviors that include shear-thinning behavior. Shear stress ramps were performed on samples at 20 and 50 degrees C using the custom geometries, and the Herschel-Bulkley model was fit to the data. The dynamic nature of the rheological properties is correlated with changes in the average fiber length at various extents of reaction, and the influence of solids concentration on the observed rheology and piping pressure losses is discussed.

09 BIOMASS FUELS↗

Development of in-use engine speed/torque heat maps across multiple heavy-duty commercial vehicle vocations

The U.S. Department of Energy (DOE) established the SuperTruck program with the goal of achieving brake thermal efficiency (BTE) greater than or equal to 55% as demonstrated in an operational heavy-duty (HD) diesel engine at a 65-miles-per-hour (mph) cruise point. Beyond the line-haul application, HD engines operate in a wide range of speed and torque conditions that are unlikely to yield the same efficiency under real-world operation. Thereby, the in-use engine heat maps described in this paper are a valuable tool to illustrate whether the engine-efficiency “sweet spot” matches the most frequent operating conditions. In this study, NREL developed engine heat maps to quantify the important operating points for various vocations using our Fleet DNA database of commercial fleet vehicle operations data. These heat maps clearly show that high-frequency operating points vary significantly according to vehicle vocation, while only a few of them match the sweet spot. Beyond the illustration, engine in-use heat maps can also be leveraged to build up reduced-order engine-efficiency models, needed by many rapid powertrain simulations. As case studies, nine reduced-order models – including line-haul truck, transfer truck, transit bus, transit bus with compressed natural gas (CNG) engine, drayage, refuse pickup, local delivery, utility truck, and school bus with CNG engine – using a trust-region reflective algorithm to fit the on-road data extracted based on the engine in-use heat maps.

33 ADVANCED PROPULSION SYSTEMS↗

Pilot Heavy-Duty Electric Vehicle Deployment for Anchorage, Alaska, Municipal Solid Waste Collection

Through a grant awarded by the U.S. Department of Energy, the Municipality of Anchorage initiated a pilot program in their Solid Waste Services (SWS) department to add heavy-duty electric trucks to its vehicle fleet. The project involves the purchase and deployment of a Peterbilt 220EV electric box truck and two Peterbilt 520EV heavy-duty electric refuse trucks. The Alaska Center for Energy and Power at the University of Alaska Fairbanks performed data analysis. Data collected include telemetry data from both types of electric trucks, charging data from the 520EV telemetry data and a Level 2 charger, and facility-level electric use data.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

220EV Box Truck Telemetry Dataset

This dataset contains telemetry data for the 520EV refuse trucks accessed through a Veracity data platform as provided by Peterbilt. The dataset contains driving data on both electric trucks used by SWS. Data were recorded at an hourly resolution and contain energy use data while driving and idling, distance driven (miles), and driving speed (miles per hour). This dataset also contains charging data on the fast charger in kilowatt-hours for each hour.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Pilot Heavy-Duty Electric Vehicle Deployment for Anchorage, Alaska, Municipal Solid Waste Collection

Through a grant awarded by the U.S. Department of Energy, the Municipality of Anchorage initiated a pilot program in their Solid Waste Services (SWS) department to add heavy-duty electric trucks to its vehicle fleet. The project involves the purchase and deployment of a Peterbilt 220EV electric box truck and two Peterbilt 520EV heavy-duty electric refuse trucks. The Alaska Center for Energy and Power at the University of Alaska Fairbanks performed data analysis. Data collected include telemetry data from both types of electric trucks, charging data from the 520EV telemetry data and a Level 2 charger, and facility-level electric use data.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Soil carbon, nitrogen, and ice content data (2014-2018) at Happy Valley and Sagwon Hills in Northern Alaska, United States

This dataset contains three data files from soil data collected by sampling soil cores and pits across a toposequence on two hillslopes in permafrost affected soils in Northern Alaska, USA. Soil cores and profiles were excavated to 3m or until auger refusal. Samples were collected by genetic soil horizons for laboratory analysis and organized into complete soil profiles ordered depth. Soil carbon, nitrogen, and ice stocks (stocks_by_core.csv) were calculated from the core dataset . Data for mean values by depth increments (20,50,100,150,200 cm) of total soc, total nitrogen, bulk density, and ice content were determined and made available in this dataset (soc-tn-bd-ice-slab_tables.csv). Stocks by site are included in a separate file (stocks_by_site.csv). Each of these three files also has an associated data dictionary file (stocks_by_core_dd.csv, soc-tn-bd-ice-slab_tables_dd.csv, stocks_by_site_dd.csv). Finally, an FLMD file is also included (FLMD_Happy_Valley_Sagwon.csv).

54 ENVIRONMENTAL SCIENCES↗

Development of a Cost-Effective Extraction Process for the Recovery of Heavy and Critical Rare Earth Elements from the Clays and Shales Associated with Coal

The primary objective of the project was to investigate and develop a novel process technology that can extract and concentrate rare earth elements (REE) from coal refuse material, namely shales and clays, to a concentration of greater than or equal to 2% by weight. The extraction and recovery technologies developed in this project leverage the low-cost ion-exchange leaching techniques that are currently applied for commercial heavy rare earth production in South China. In addition to the ion-exchange extraction technology, the project also investigated a novel method of solution concentration and recovery based on ion and/or precipitate flotation.

01 COAL, LIGNITE, AND PEAT↗