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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Data for Optimization of Pre-Commercial Enzymes Dosage for a Potential Lignocellulosic Biorefinery

Lignocellulolytic enzymes remain one of the primary cost constraints in second-generation (2G) ethanol biorefineries. Achieving efficient hydrolysis of structural carbohydrates with minimal enzyme dosage, maintaining slurry fermentability for industrially relevant ethanol titers, and maximizing ethanol yield per ton of biomass are among the major challenges in 2G processes. In this study, we optimized the dosages of pre-commercial cellulase (NS22257) and hemicellulase (NS22244) on pilot-scale, hydrothermally pretreated lignocellulosic substrates. Enzyme dosages were evaluated at three levels: 20 mg of cellulase with 7.25 mg of hemicellulase (ED-1), 40 mg with 14.5 mg (ED-2), and 60 mg with 21.75 mg (ED-3). As expected, the highest sugar yields were obtained with ED-3; however, for sweet sorghum, oilcane, and miscanthus, sugar yields from ED-2 and ED-3 were not significantly different (p < 0.05). For example, sweet sorghum produced 123.78 ± 1.54 g L−1 and 125.76 ± 0.46 g L−1 of total sugars (glucose and xylose) with ED-2 and ED-3, respectively. Although energycane exhibited a statistically significant difference between ED-2 and ED-3, the incremental gain with ED-3 was modest, increasing sugar release by only 9.02 g L−1 relative to ED-2. Importantly, ED-1 resulted in sugar yields of 88.88 ± 3.64 to 106.86 ± 1.21 g L−1, sufficient to achieve ethanol titers ≥40 g L−1, the threshold required for industrial relevance. A semi-integrated bioprocess validated this outcome, producing 42.09 ± 2.38 g L−1 ethanol and an estimated yield of 213.38 L of ethanol per dry ton of pretreated biomass, requiring only 20.83 L of cellulase and 6.25 L of hemicellulase per ton. Remarkably, these enzyme dosages were approximately tenfold lower than those reported in prior studies.

Energycane↗
DOE OSTI2020

A systems genetics approach to deciphering the effect of dosage variation on leaf morphology in Populus

Abstract Gene copy number variation is frequent in plant genomes of various species, but the impact of such gene dosage variation on morphological traits is poorly understood. We used a large population of Populus carrying genomically characterized insertions and deletions across the genome to systematically assay the effect of gene dosage variation on a suite of leaf morphology traits. A systems genetics approach was used to integrate insertion and deletion locations, leaf morphology phenotypes, gene expression, and transcriptional network data, to provide an overview of how gene dosage influences morphology. Dosage-sensitive genomic regions were identified that influenced individual or pleiotropic morphological traits. We also identified cis-expression quantitative trait loci (QTL) within these dosage QTL regions, a subset of which modulated trans-expression QTL as well. Integration of data types within a gene co-expression framework identified co-expressed gene modules that are dosage sensitive, enriched for dosage expression QTL, and associated with morphological traits. Functional description of these modules linked dosage-sensitive morphological variation to specific cellular processes, as well as candidate regulatory genes. Together, these results show that gene dosage variation can influence morphological variation through complex changes in gene expression, and suggest that frequently occurring gene dosage variation has the potential to likewise influence quantitative traits in nature.

Biochemistry & Molecular Biology↗
DOE OSTI2019

A comprehensive genomic scan reveals gene dosage balance impacts on quantitative traits in Populus trees

Gene dosage variation and the associated changes in gene expression influence a wide variety of traits, ranging from cancer in humans to yield in plants. It is also expected to affect important traits of ecological and agronomic importance in forest trees, but this variation has not been systematically characterized or exploited. Here we performed a comprehensive scan of the Populus genome for dosage-sensitive loci affecting quantitative trait variation for spring and fall phenology and biomass production. The study population was a large collection of clonally propagated F1 hybrid lines of Populus that saturate the genome 10-fold with deletions and insertions (indels) of known sizes and positions. As a group, the phenotypic means of the indel lines consistently differed from control nonindel lines, with an overall negative effect of both insertions and deletions on all biomass-related traits but more diverse effects and an overall wider phenotypic distribution of the indel lines for the phenology-related traits. We also investigated the correlation between gene dosage at specific chromosomal locations and phenotype, to identify dosage quantitative trait loci (dQTL). Such dQTL were detected for most phenotypes examined, but stronger effect dQTL were identified for the phenology-related traits than for the biomass traits. Furthermore our genome-wide screen for dosage sensitivity in a higher eukaryote demonstrates the importance of global genomic balance and the impact of dosage on life history traits.

09 BIOMASS FUELS↗
NASA NTRS1998

Bioavailability of intranasal promethazine dosage forms in dogs

Intramuscular promethazine (PMZ) is used aboard the US Space Shuttle to ameliorate symptoms of space motion sickness. Bioavailability after an oral dose of PMZ during space flight is thought to be impaired because of gastrointestinal disturbances associated with weightlessness and space motion sickness. In an attempt to find an alternative dosage form for use in space, we evaluated two intranasal (i.n.) dosage forms of PMZ in dogs for absorption and bioavailability relative to that of an equivalent intramuscular dose. Promethazine (5 mg kg-1) was administered as two intranasal dosage forms and as an intramuscular (i.m.) dose to three dogs in a randomised cross-over design. Serial blood samples were taken and analysed for PMZ concentrations and the absorption and bioavailability of PMZ were calculated for the three dosage forms. PMZ absorption from the carboxymethyl cellulose microsphere i.n. dosage form was more rapid and complete than from the myverol cubic gel formulation or from an i.m. injection. Bioavailability of the microsphere formulation was also greater than that of the gel formulation (AUC 3009 vs 1727 ng h ml-1). The bioavailability of the two i.n. dosage forms (relative to that of the i.m. injection) were 94% (microsphere) and 54% (gel). The i.n. microsphere formulation of PMZ offers great promise as an effective non-invasive alternative for treating space motion sickness due to its rapid absorption and bioavailability equivalent to the i.m. dose.

NASA Center JSC↗
DOE OSTI2022

Coupling AFEX and steam-exploded sugarcane residue pellets with a room temperature CIIII-activation step lowered enzyme dosage requirements for sugar conversion

In this study, the potential integration of steam explosion (StEx) and ammonia fiber expansion (AFEX) with existing sugar/ethanol mills to form decentralized pre-processing depots was explored. Both StEx and AFEX pretreatment facilitated the production of sugarcane bagasse (SCB) and cane leaf matter (CLM) pellets with significantly higher bulk density, mechanical durability, and hydrophobicity relative to their untreated biomass pellet controls. However, ethanol production from standalone StEx and AFEX-treated SCB and CLM pellets required enzyme dosages greater than 21 mg/g glucan to achieve enzymatic hydrolysis sugar yields of 75% and ethanol titres greater than 40 g.L -1 . Coupling AFEX-treated SCB or CLM pellets with a room temperature CIII I -activation step using liquid ammonia lowered enzyme dosage requirements by more than 50% without affecting ethanol titers and production yields (greater than300 L per Mg residual dry matter raw dry biomass (RDM)). In contrast, treating StEx-treated pellets with CIIII-activation using liquid ammonia did not result in similar enzyme dosage reductions, due to pseudo-lignin formation, leading to enzyme deactivation and/or lignin blockage that retarded enzymatic hydrolysis at low enzyme dosages. A gross energy conversion assessment revealed that low enzyme dosage (3-4 mg enzyme/g RDM) ethanol and electricity co-production from AFEX and CIII I -activated SCB and CLM can recover up to 73% of the energy in the untreated biomass, compared to 54% recovered by StEx and CIII I -activation. The results from this work suggest that StEx or AFEX based pre-processing depots can produce dense and mechanically durable biomass pellets. The AFEX-treated pellets can be easily upgraded using a room temperature CIII I -activation step at the biorefinery to significantly reduce bioconversion enzymes.

42 ENGINEERING↗
DOE OSTI2020

O 2 dosage as a descriptor of TWC performance under lean/rich dithering in stoichiometric natural gas engines

The effects of oscillations in gas composition, known as lean/rich dithering, on the performance of a commercial Pd-based three-way catalyst (TWC) for stoichiometric natural gas (NG) engines were evaluated using synthetic exhaust flow reactor experiments. Under simulated NG exhaust conditions, NO conversion was intimately correlated to CH 4 conversion at slightly fuel-rich operating conditions. CH 4 conversion significantly varied with lambda (or O 2 concentration) and depended on the direction of the lambda change. The dynamic CH 4 conversion is likely related to the change of catalyst oxidation state and structures of Pd active sites. The CH 4 -NO cross-over point was found at a rich-biased lambda rather than stoichiometry. Compared to static operation, catalyst performance was much higher under a realistic dithering condition. The impacts of dithering parameters including amplitude and frequency on CH 4 and NO conversions were explored. O 2 dosage is proposed as an effective descriptor of the TWC dithering performance. In the O 2 -dosage space, the performance of distinct dithering parameters collapse, helping to elucidate the fundamental influence of dithering parameters on TWC performance. With the help of O2 dosage, an optimal operating window leading to high CH 4 and NO conversions was identified. A higher dithering amplitude is required to keep the catalyst in a reduced state for higher CH 4 and NO conversions, while an appropriate O 2 dosage that does not exceed the breakthrough OSC is necessary to avoid excess O 2 that results in NO slip. The dithering amplitude and O 2 -dosage-metric maps provide a new method for studying dynamic TWC performance and identifying optimum operation strategies.

03 NATURAL GAS↗
DOE OSTI2026

Optimization of pre-commercial enzyme dosage for a potential lignocellulosic biorefinery

Lignocellulolytic enzymes remain one of the primary cost constraints in second-generation (2G) ethanol biorefineries. Achieving efficient hydrolysis of structural carbohydrates with minimal enzyme dosage, maintaining slurry fermentability for industrially relevant ethanol titers, and maximizing ethanol yield per ton of biomass are among the major challenges in 2G processes. In this study, we optimized the dosages of pre-commercial cellulase (NS22257) and hemicellulase (NS22244) on pilot-scale, hydrothermally pretreated lignocellulosic substrates. Enzyme dosages were evaluated at three levels: 20 mg of cellulase with 7.25 mg of hemicellulase (ED-1), 40 mg with 14.5 mg (ED-2), and 60 mg with 21.75 mg (ED-3). As expected, the highest sugar yields were obtained with ED-3; however, for sweet sorghum, oilcane, and miscanthus, sugar yields from ED-2 and ED-3 were not significantly different ( p < 0.05). For example, sweet sorghum produced 123.78 ± 1.54 g L −1 and 125.76 ± 0.46 g L −1 of total sugars (glucose and xylose) with ED-2 and ED-3, respectively. Although energycane exhibited a statistically significant difference between ED-2 and ED-3, the incremental gain with ED-3 was modest, increasing sugar release by only 9.02 g L −1 relative to ED-2. Importantly, ED-1 resulted in sugar yields of 88.88 ± 3.64 to 106.86 ± 1.21 g L −1 , sufficient to achieve ethanol titers ≥40 g L −1 , the threshold required for industrial relevance. A semi-integrated bioprocess validated this outcome, producing 42.09 ± 2.38 g L −1 ethanol and an estimated yield of 213.38 L of ethanol per dry ton of pretreated biomass, requiring only 20.83 L of cellulase and 6.25 L of hemicellulase per ton. Remarkably, these enzyme dosages were approximately tenfold lower than those reported in prior studies.

Deshavath, Narendra Naik [Univ. of Illinois at Urb↗
DOE OSTI2018

Predictive drug dosage control through a Fokker–Planck observer

During the years, various techniques have been presented for optimal control of tumor growth for which its stochastic behavior has rarely been considered. This article uses the well-known Gompertz stochastic model, for describing tumor growth, and by receding horizon model predictive control (RH-MPC) scheme computes the drug dosage for minimizing the tumor-cell population. To do this, a predictive control problem is defined based on the difference between the probability density function of tumor-cell population and the desired probability density function. In the model, both the drug dosage limitation and the Fokker–Planck equation have been considered as constraints. By solving this problem, the drug dosage which is considered as an external input to tumor model, is computed. In this article, the Fokker–Planck equation is used (1) as a nonlinear observer of probability density function of tumor-cell population and (2) a mapping vehicle from stochastic to deterministic domain. The Fokker–Planck equation is written for the Gompertz stochastic model of tumor growth. The equation is then solved through the path integral method. In this way, the probability density function of tumor-cell population, which contains the entire stochastic characteristics of the tumor growth, is obtained for any instance of time. The simulation results have also been presented for the evaluation of the suggested approach. The results show that the tumor-cell population can be controlled within a number of time windows (15 time windows in our case study) if an appropriate desired PDF is selected.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Effects of alkali dosage and silicate modulus on autogenous shrinkage of alkali-activated slag cement paste

Autogenous shrinkage of alkali-activated slag cement (AASC) paste prepared with different levels of alkali dosage and silicate modulus (M{sub s}) is investigated. The results show that autogenous shrinkage of AASC paste increases at a decreasing rate with alkali dosage, which is attributed to enhanced capillary pore pressure and syneresis of C-A-S-H gels. Autogenous shrinkage of AASC paste with a constant alkali dosage increases as M{sub s} increases from 0.5 to 1.0, followed with a reduction as M{sub s} further increases to 2.0. Increasing M{sub s} initially enhances the capillary pore pressure due to the enhanced reaction degree, and promotes the formation of saturated capillary pores and viscoelasticity, which facilitates the autogenous shrinkage of AASC paste. However, excessive silicate in the activator retards the internal moisture consumption, and subsequently decreases the autogenous shrinkage of AASC paste. Furthermore, increasing M{sub s} can also intensify syneresis of C-A-S-H gels, contributing to the early-age autogenous shrinkage of AASC paste.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Accelerating pathway evolution by increasing the gene dosage of chromosomal segments

Experimental evolution is a critical tool in many disciplines, including metabolic engineering and synthetic biology. However, current methods rely on the chance occurrence of a key step that can dramatically accelerate evolution in natural systems, namely increased gene dosage. Our studies sought to induce the targeted amplification of chromosomal segments to facilitate rapid evolution. Since increased gene dosage confers novel phenotypes and genetic redundancy, we developed a method, Evolution by Amplification and Synthetic Biology (EASy), to create tandem arrays of chromosomal regions. In Acinetobacter baylyi , EASy was demonstrated on an important bioenergy problem, the catabolism of lignin-derived aromatic compounds. The initial focus on guaiacol (2-methoxyphenol), a common lignin degradation product, led to the discovery of Amycolatopsis genes ( gcoAB ) encoding a cytochrome P450 enzyme that converts guaiacol to catechol. However, chromosomal integration of gcoAB in Pseudomonas putida or A. baylyi did not enable guaiacol to be used as the sole carbon source despite catechol being a growth substrate. We report in ~1,000 generations, EASy yielded alleles that in single chromosomal copy confer growth on guaiacol. Different variants emerged, including fusions between GcoA and CatA (catechol 1,2-dioxygenase). This study illustrates the power of harnessing chromosomal gene amplification to accelerate the evolution of desirable traits.

09 BIOMASS FUELS↗
DOE OSTI2019

Radiation dosages for NbFeB magnets in CBETA (CBETA Tech Note 040)

This paper creates models of various components of CBETA and conducts simulations of electron beam irradiation to calculate dose rates on NdFeB permanent magnets. Using Geant4 simulation software, two models were created which red 42MeV beams and measured the resulting dosage of radiation on nearby permanent magnets. In the first model, the beam was incident on a viewscreen, and the maximum dose rate obtained on a nearby magnet was .97±.0007 Gy/μC which corresponds to 1910±3 hrs of continuous operation at a beam current of 150 pA, if the maximum allowed dose is 1 kGy. The second model is of a splitter section, and the results indicate that radiation dose rate increases as a function of the incident angle as the beam enters the 42MeV chamber line. In Model II, a half-quadrupole magnet experienced the highest dose rate at 0.0909±.0005 Gy/μC, corresponding to 20,400±140 hrs of operation at 150 pA until the magnet reaches a dose of 1 kGy. For this second model, it was also observed that vertical momenta proportionally decrease radiation dosage on the magnets.

43 PARTICLE ACCELERATORS↗
NASA NTRS1994

Deriving a dosage-response relationship for community response to high-energy impulsive noise

The inability to systematically predict community response to exposure to sonic booms (and other high energy impulsive sounds) is a major impediment to credible analyses of the environmental effects of supersonic flight operations. Efforts to assess community response to high energy impulsive sounds are limited in at least two important ways. First, a paucity of appropriate empirical data makes it difficult to infer a dosage-response relationship by means similar to those used in the case of general transportation noise. Second, it is unclear how well the 'equal energy hypothesis' (the notion that duration, number, and level of individual events are directly interchangeable determinants of annoyance) applies to some forms of impulsive noise exposure. Some of the issues currently under consideration by a CHABA working group addressing these problems are discussed. These include means for applying information gained in controlled exposure studies about different rates of growth of annoyance with impulsive and non-impulsive sound exposure levels, and strategies for developing a dosage-response relationship in a data-poor area.

Fidell, Sanford↗
NASA NTRS1992

Low-dosage micronized 17 beta-estradiol prevents bone loss in postmenopausal women

With the use of a double-blind, randomized, dose-ranging design, we tested during an 18-month period the degree of protection against postmenopausal bone loss afforded by micronized 17 beta-estradiol in dosages of 0.5, 1.0, and 2.0 mg. All subjects received supplementation to ensure a minimum of 1500 mg calcium daily. Fifty-one subjects completed at least 1 year of follow-up bone density measurements by quantitative computed tomography and by single- and dual-photon absorptiometry. In the placebo group spinal trabecular bone density decreased 4.9% annually (p less than 0.001), whereas in those taking micronized 17 beta-estradiol bone density tended to increase (annual increases of 0.3% in the 0.5 mg micronized 17 beta-estradiol group, 1.8% in the 1.0 mg micronized 17 beta-estradiol group, and 2.5% in the 2.0 mg micronized 17 beta-estradiol group). After completing the double-blind phase, 41 subjects completed an additional 18 months of follow-up while taking 1.0 mg micronized 17 beta-estradiol. During this time one third of the subjects were randomly assigned to discontinue calcium supplements. Among those who previously received placebo, trabecular bone density increased 4.3% annually, whereas among those who had used micronized 17 beta-estradiol, trabecular bone density response was inversely related to the dosage previously used. Additionally and independently, the level of calcium intake showed a statistically significant correlation with the change in spinal trabecular bone density (r = 0.37, p = 0.02). We conclude that micronized 17 beta-estradiol has a continuous skeletal dose-response effect in the range of 0.5 to 2.0 mg and that calcium intake positively modifies the skeletal response to 1.0 mg micronized 17 beta-estradiol.

Randomized Controlled Trial↗
NASA NTRS2007

Relative Bioavailability of Scopolamine Dosage Forms and Interaction with Dextroamphetamine

The NASA Reduced Gravity Office (RGO) uses scopolamine (SCOP) and in combination with dextoamphetamine (DEX) to manage motion sickness symptoms during parabolic flights. The medications are dispensed as custom dosage forms as gelatin capsules. Anecdotal evidence of efficacy suggests that these formulations are unreliable and less efficacious for the treatment of motion sickness. We estimated bioavailability of four different oral formulations used by NASA for the treatment of motion sickness. Twelve healthy, non-smoking subjects between 21and 48 years of age received four treatments on separate days in a randomized fashion; the treatments were 0.8 mg SCOP alone as tablet, 0.8 mg SCOP alone in gel cap, 0.8 mg SCOP and 10 mg DEX as tablets, and 0.8 mg SCOP and 10 mg DEX in gel cap. After each treatment, blood, saliva, and urine samples were collected at scheduled time intervals for 24 h after dosing. Bioavailability and pharmacokinetic parameters were calculated and compared using ANOVA. After administration of SCOP tablets alone, maximum concentration (C(sub max)) and time for maximum concentration (t(sub max)) were 0.26 plus or minus 0.04 ng/mL and 0.71 plus or minus 0.02 h, respectively; volume of distribution, and clearance were 47.6 plus or minus 4.72 L/kg and 23.0 plus or minus 4.58 L/h/kg, respectively. SCOP t(sub max) after administration as gelcaps was significantly longer than that with tablets (1.04 h, p less than 0.05), but no significant differences in other pharmacokinetic parameters of SCOP were observed between the two dosage forms. When coadministered with DEX, the area underneath the concentration versus time curve (AUC) of SCOP was significantly reduced to 0.61 plus or minus 0.09 and 0.64 plus or minus 0.11 ng (raised dot) h/mL after administration as a tablet or gelcap formulation, respectively; SCOP C(sub max) was lower after coadministration with DEX, this difference, however, was not statistically significant. Delayed absorption with gelcaps coupled with reduced bioavailability with DEX coadministration may have resulted in the observed treatment failure with some of these formulations. This could result from failure to reach minimum effective concentrations after treatment with gelcap formulations before parabolic flights. A new nomogram for dosing is proposed for treatment with SCOP gelcaps or SCOP-DEX combination.

Boyd, Jason L.↗
DOE OSTI2018

Development of a Dosage System for the Incineration of Radioactive and Particle-laden Liquid - 18080

The alpha incinerator has been operating since 1999 at the CEA Valduc center in France for the treatment of alpha-bearing technological waste. The fact that the incinerator has been working smoothly for 18 years and the experience gained during this period indicate that it can also be used to treat other types of waste, such as Ion-Exchange Resin (IER) suspensions. The aims of an R and D project initiated in 2014 were to develop a dosage system allowing these suspensions to be injected into the heart of the treatment system and to evaluate the performance of the incinerator when these materials are added to technological waste. This article describes the work carried out to develop a dosage system for heavily particle-laden fluids (with more than 50 vol% solid particles), with the aim of delivering waste continuously into the treatment furnace. The proposed device consists of a feeding tank equipped with a stirrer, a piston pump, and a pneumatic transport system. Reliability has been improved by replacing the initial sealing system (a piston with seals), by a very tight (∼4 μm gap), therefore seal-less, sleeve/piston unit. Adjusting the carrying gas flow has optimized the system as a whole, making it safer and more robust. The system has been qualified through more than 1000 hours of operation and the results obtained for the incineration of IER suspensions suggest that industrial transport is feasible and will thus begin soon. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗