Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “corn”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Structural Break and Causal Analyses of U.S. Corn Use for Ethanol and Other Corn Market Variables

The causal basis for many of the relationships in models used to estimate the indirect effects of U.S. biofuels on global agricultural markets has not been adequately established. This paper addresses this gap by examining causal interactions among corn market variables through which the indirect effects of U.S. corn use for ethanol would be transmitted. Specifically, structural break and causal analyses of U.S. corn supply, uses, trade, and price are performed using quarterly data for marketing years 1986 to 2017. The structural break analysis identifies three breaks in corn use for ethanol that reflect the policy-driven evolution of U.S. corn ethanol production and other market factors. The causality analysis finds that U.S. corn use for ethanol is not a driver of the corn price and net corn exports. Changes in corn supply and domestic corn use are found to be the key factors in accommodating the large increase in corn use for ethanol between 2003 and 2010. These results mean that common assumptions linking U.S. corn ethanol production to large reductions in corn availability and exports, and higher global corn prices merit reconsideration.

09 BIOMASS FUELS↗
DOE OSTI2021

Innovative and Economically Beneficial Use of Corn and Corn Products in Electrochemical Energy Storage Applications

The United States is by far the largest corn producer worldwide, with corn yields steadily increasing for the past decades. In many midwestern U.S. states such as Iowa, Illinois, and Nebraska, corn farmers currently grow more corn than consumers can utilize as human food or animal feed. To sustain the economic viability of corn farmers, it is critical that new uses and markets for corn, corn byproducts from harvesting, corn industrial products, and corn byproducts from industrial processing should be discovered, giving the highest return to corn producers. With the increasing popularity of electric vehicles and grid-level energy storage systems for renewable energy, there has been an ever-growing interest in improving existing energy storage technologies as well as developing new ones. During this development, a great amount of effort has been focused on exploiting cost-effective solutions utilizing sustainable materials derived from renewable biomass. Here, innovative and economically beneficial uses of corn and corn products in various energy storage applications, such as lithium-ion batteries, solid-state batteries, and redox flow batteries, are looked at comprehensively, which may shed light on how to establish an environmentally sustainable, technically feasible, and economically beneficial solution to support the corn industry.

25 ENERGY STORAGE↗
DOE OSTI2025

Data for Attributing Differences of Solar-Induced Chlorophyll Fluorescence (SIF)-Gross Primary Production (GPP) Relationships between Two C4 Crops, Corn and Miscanthus

Information to characterize the solar-induced chlorophyll fluorescence (SIF)-gross primary production (GPP) relationship in C4 cropping systems remains limited. The annual C4 crop corn and perennial C4 crop miscanthus differ in phenology, canopy structure and leaf physiology. Investigating the SIF-GPP relationships in these species could deepen our understanding of SIF-GPP relationships within C4 crops. Using in situ canopy SIF and GPP measurements for both species along with leaf-level measurements, we found considerable differences in the SIF-GPP relationships between corn and miscanthus, with a stronger SIF-GPP relationship and higher slope of SIF-GPP observed in corn compared to miscanthus. These differences were mainly caused by leaf physiology. For miscanthus, high non-photochemical quenching (NPQ) under high light, temperature and water vapor deficit (VPD) conditions caused a large decline of fluorescence yield (ΦF), which further led to a SIF midday depression and weakened the SIF-GPP relationship. The larger slope in corn than miscanthus was mainly due to its higher GPP in mid-summer, largely attributed to the higher leaf photosynthesis and less NPQ. Our results demonstrated variation of the SIF-GPP relationship within C4 crops and highlighted the importance of leaf physiology in determining canopy SIF behaviors and SIF-GPP relationships.

Feedstock Production↗
DOE OSTI2021

Varied farm-level carbon intensities of corn feedstock help reduce corn ethanol greenhouse gas emissions

Abstract A reduction in the overall carbon intensity (CI) of a crop-based biofuel can be achieved by cutting down the CI of the biofuel’s feedstock, which in turn correlates significantly to agricultural management practices. Proposals are being made to incentivize low-carbon biofuel feedstocks under U.S. fuel regulatory programs to promote sustainable farming practices by individual farms. For such an incentive scheme to function properly, robust data collection and verification are needed at the farm level. This study presents our collaboration with U.S. private sector companies to collect and verify the corn production data necessary for feedstock-specific CI calculation at the farm level, through a carefully designed questionnaire, to demonstrate the practicality and feasibility of data collection at scale. We surveyed 71 farms that produced 0.2 million metric tons of corn grain in 2018 in a Midwestern U.S. state to obtain information on key parameters affecting corn ethanol feedstock CI, such as grain yields, fertilizer/chemical application rates, and agronomic practices. Feedstock-specific CI was calculated in the unit of grams (g) CO 2 equivalent (CO 2 e) of greenhouse gases per kilogram (kg) of corn produced. Results showed large CI variations—from 119 to 407 g CO 2 e kg −1 of corn—due to the farm-level inventory, while the production-weighted average CI for all surveyed farms was 210 g CO 2 e kg −1 , comparable to the national average CI of 204 g CO 2 e kg −1 . The nitrogen fertilizer type applied and rate were identified as key factors contributing most to CI variations at the farm level. The estimated N 2 O emissions from fertilizer and biomass nitrogen inputs to soil accounted for 51% of the overall farm-level CI and therefore need to be better monitored at farm level with high resolution. We concluded that this feedstock-specific, farm-level CI evaluation has the potential to be used to incentivize low-carbon feedstock for biofuel production.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Defatted Microalgae-Mediated Enrichment of n–3 Polyunsaturated Fatty Acids in Chicken Muscle Is Not Affected by Dietary Selenium, Vitamin E, or Corn Oil

We previously showed enrichments of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in broiler chicks fed defatted microalgae. The aims of this study were to determine 1) if the enrichments affected meat texture and were enhanced by manipulating dietary corn oil, selenium, and vitamin E concentrations and 2) how the enrichments corroborated with hepatic gene expression involved in biosynthesis and oxidation of EPA and DHA. Day-old hatching Cornish Giant cockerels (n= 216) were divided into 6 groups (6 cages/group and 6 chicks/cage). Chicks were fed 1 of the 6 diets: a control diet containing 4% corn oil, 25 IU vitamin E/kg, and 0.2 mg Se/kg (4CO), 4CO + 10% microalgae (defatted Nannochloropsis oceanica; 4CO+ MA), 4CO+ MA – 2% corn oil (2CO+MA), 2CO+MA + 75 IU vitamin E/kg (2CO+MA+E), 2CO+MA + 0.3 mg Se/kg (2CO+MA+Se), and 2CO+MA+E + 0.3 mg Se/kg (2CO+MA+E+Se). After 6 wk, fatty acid profiles, DHA and EPA biosynthesis and oxidation, gene expression, lipid peroxidation, antioxidant status, and meat texture were measured in liver, muscles, or both. Compared with the control diet, defatted microalgae (4CO+MA) enriched (P< 0.05) DHA and EPA by ≤116 and 24 mg/100 g tissue in the liver and muscles, respectively, and downregulated (41–76%, P< 0.01) hepatic mRNA abundance of 4 cytochrome P450 (CYP) enzymes (CYP2C23b, CYP2D6, CYP3A5, CYP4V2). Supplemental microalgae decreased (50–82%, P< 0.05) lipid peroxidation and improved (16–28%, P< 0.05) antioxidant status in the liver, muscles, or both. Furthermore, the microalgae-mediated enrichments in the muscles were not elevated by altering dietary corn oil, vitamin E, or selenium and did not affect meat texture. The microalgae-mediated enrichments of DHA and EPA in the chicken muscles were associated with decreased hepatic gene expression of their oxidation, but were not further enhanced by altering dietary corn oil, vitamin E, or selenium.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Yield stress and flow behavior of enzyme liquefied slurries from corn cobs and corn stover pellets

With the increase in population, the world will depend on renewable sources to meet the increasing energy needs. The use of lignocellulosic biomass as a renewable source has been proven efficient for conversion to cellulosic ethanol and capable of contributing to thresholds for energy demand while reducing greenhouse gases by 90% when compared with fossil fuels. However, limitations in feeding and flow within biorefineries is encountered when system plugging occurs due to biomass compaction and a high yield stress for slurries formed during its processing, thereby preventing transport of biomass materials between plant unit operations. In some cases, this leads to unexpected plant shutdowns increasing industrial operational costs. As an alternative, enzyme-assisted liquefaction for slurry creation from corn stover at solids loadings up to 30% is reported in this work. Two different kinds of biomass (pelleted corn stover and cobs) were liquefied in a fed-batch process using commercial enzymes Celluclast 1.5L or Ctec-2 at 1FPU or 3 FPU per gram of dry solids in 10 mM sodium citrate buffer solution (pH 4.8). Pellets were fed into a 1 L stirred bioreactor according to a pre-defined fed-batch protocol over the first 5 hours until reaching 30% of solids loading. After 6, 24 and 96 hours, samples were taken and characterized with respect to their sugar composition, rheology and water absorption. Successful slurry creation with dramatically reduced yield stress was achieved for corn stover for both assessed enzymes. Yield stresses of 178±7 Pa (3 FPU, Celluclast 1.5L) and 79±6 Pa (3 FPU, Ctec-2) were measured for corn stover at 24 hours, compared to 6,000 Pa for samples without enzyme. Yield stress was 155± 29 Pa (3FPU, Ctec-2) and 257 ± 72 Pa (1 FPU,Celluclast 1.5L) for corn cobs at 24 hours. Yield stress decreased when residence time increased with an enhanced fluidity noted for higher enzyme concentrations. A profile for 6, 24 and 96h of yield stress measurements is presented.

Guitierrez, Diana↗
DOE OSTI2018

Life-cycle greenhouse gas emissions of corn kernel fiber ethanol

Corn kernel fiber ethanol that can be produced concurrently with corn starch ethanol has recently been approved as cellulosic biofuel in the USA, suggesting that fiber ethanol could be eligible for a higher credit price than conventional starch ethanol due to its anticipated lower greenhouse gas (GHG) emissions. A life-cycle analysis was conducted to quantify ethanol's GHG emissions. Here we show that fiber ethanol's life-cycle GHG emissions (36-39 g CO(2)e MJ(-1)) are close to meeting the US cellulosic biofuel's legislative mandate of 60% GHG emissions reduction relative to gasoline (similar to 94 g CO(2)e MJ(-1)), with slightly lower emissions under the nth plant mature fiber technology than under the state of technology (SOT). The co-product, distiller's grain with solubles (DGS), can notably affect fiber ethanol's GHG emissions, and this impact may need to be further examined when evidence of DGS market impacts becomes available. (c) 2018 Society of Chemical Industry and John Wiley & Sons, Ltd

biofuel↗
DOE OSTI2020

Deacetylation and Mechanical Refining (DMR) and Deacetylation and Dilute Acid (DDA) Pretreatment of Corn Stover, Switchgrass, and a 50/50 Corn Stover/Switchgrass Blend

The most economical feedstock available to future lignocellulosic biorefineries may be a feedstock blend. Corn stover, switchgrass, and a 50:50 blend of corn stover and switchgrass were subjected to three different dilute alkali deacetylation conditions in a 90 L reactor prior to either mechanical refining (DMR) in a disc refiner followed by a Szego mill or dilute acid pretreatment (DDA) at five different conditions in a 4 L batch steam explosion reactor. The forty-five DDA and nine DMR slurries were subjected to high solids enzymatic hydrolysis at an enzyme loading of 15 mg protein per gram cellulose using Novozymes Cellic CTec3 (DDA) or a 4:1 mix of Novozymes Cellic CTec3:HTec 3 (DMR). The highest glucose yield was achieved using DMR processed corn stover from the high severity deacetylation condition (92 °C and 100 kg NaOH/ODMT) at 95.9% ± 0.8%, while the greatest monomeric glucose yields for switchgrass were between 75% to 80%. The glucose yields from saccharification of the 50:50 corn stover/switchgrass blend was approximately the average of the two individual feedstocks for both DDA and DMR processes. Statistical analysis showed that for a given feedstock type dilute alkali deacetylation severity had a significant impact (p < 0.05) on enzymatic hydrolysis yields, and for a given deacetylation severity the feedstock type had a significant effect on glucose conversion with the addition of switchgrass resulting in lower glucose yields. A blending strategy to maximize enzymatic hydrolysis sugar yields while reducing carbohydrate solubilization during the alkaline treatment step was proposed that allows deacetylation of feedstocks with different recalcitrance at optimal conditions for that feedstock, then blending prior to enzymatic hydrolysis.

BIOMASS FUELS,INORGANIC, ORGANIC, PHYSICAL, AND AN↗
DOE OSTI2022

CFD-DEM Modeling of Autothermal Pyrolysis of Corn Stover with a Coupled Particle- and Reactor-Scale Framework

Autothermal operation of fast pyrolysis is an efficient process-intensification technique wherein exothermic oxidation reactions are used to overcome the heat-transfer bottleneck of conventional pyrolysis. The development of accurate, reliable modeling toolsets is imperative to generating a deeper understanding of biomass autothermal pyrolysis systems to support scale-up and industrial deployment. This modeling effort describes the development of single-particle and reactor models which incorporate detailed reaction schemes and simultaneous exothermic oxidation reactions. The particle-scale model was parameterized for corn stover feedstock with particle morphology, density, ash content, and biopolymer composition, all of which impact the emergent conversion characteristics during pyrolysis. Results were then used to parameterize a reactor-scale autothermal pyrolysis model, which was developed using a coarse-grained computational fluid dynamic-discrete element method. The simulation results compared well with experimental results, with the predicted bio-oil, light gas, and biochar yield within 3.0 wt% of the experimental yields. Further analyses were performed to test the influence of equivalence ratio, biomass injection position, and particle size distribution on autothermal pyrolysis. The analysis of the physio-chemical properties of the fluid and solid phase inside the reactor and at the reactor outlet help reveal important process interactions of autothermal pyrolysis.

BIOMASS FUELS,INORGANIC, ORGANIC, PHYSICAL, AND AN↗
DOE OSTI2020

Engineered Pseudomonas putida simultaneously catabolizes five major components of corn stover lignocellulose: Glucose, xylose, arabinose, p-coumaric acid, and acetic acid

Valorization of all major lignocellulose components, including lignin, cellulose, and hemicellulose is critical for an economically viable bioeconomy. In most biochemical conversion approaches, the standard process separately upgrades sugar hydrolysates and lignin. Here, we present a new process concept based on an engineered microbe that could enable simultaneous upgrading of all lignocellulose streams, which has the ultimate potential to reduce capital cost and enable new metabolic engineering strategies. Specifically, we engineered Pseudomonas putida, a robust microorganism capable of catabolizing aromatic compounds, organic acids, and D-glucose, to utilize D-xylose and L-arabinose by tuning D-xylose transport and pentose phosphate pathway flux. Distinct L-arabinose pathways enabled D-glucose, D-xylose, and L-arabinose co-utilization in minimal medium using model compounds as well as corn stover hydrolysate. After modifying catabolite repression, our engineered P. putida simultaneously co-utilized five representative compounds from cellulose, hemicellulose, and lignin, demonstrating the feasibility of simultaneously upgrading total lignocellulosic biomass to value-added chemicals.

Elmore, Joshua R.↗
NASA NTRS2007

Comparison of Measurements and FluorMOD Simulations for Solar Induced Chlorophyll Fluorescence and Reflectance of a Corn Crop under Nitrogen Treatments [SIF and Reflectance for Corn]

The FLuorescence Explorer (FLEX) satellite concept is one of six semifinalist mission proposals selected in 2006 for pre-Phase studies by the European Space Agency (ESA). The FLEX concept proposes to measure passive solar induced chlorophyll fluorescence (SIF) of terrestrial ecosystems. A new spectral vegetation Fluorescence Model (FluorMOD) was developed to include the effects of steady state SIF on canopy reflectance. We used our laboratory and field measurements previously acquired from foliage and canopies of corn (Zea mays L.) under controlled nitrogen (N) fertilization to parameterize and evaluate FluorMOD. Our data included biophysical properties, fluorescence (F) and reflectance spectra for leaves; reflectance spectra of canopies and soil; solar irradiance; plot-level leaf area index; and canopy SIF emissions determined using the Fraunhofer Line Depth principal for the atmospheric telluric oxygen absorption features at 688 nm (O2-beta) and 760 nm (O2-alpha). FluorMOD simulations implemented in the default "look-up-table" mode did not reproduce the observed magnitudes of leaf F, canopy SIF, or canopy reflectance. However, simulations for all of these parameters agreed with observations when the default FluorMOD information was replaced with measurements, although N treatment responses were underestimated. Recommendations were provided to enhance FluorMOD's potential utility in support of SIF field experiments and studies of agriculture and ecosystems.

Middleton, Elizabeth M.↗