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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 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Preparation and Characterization of New Environmental Functional Polymers Based on Vanillin and N-isopropylacrylamide for Post Polymerization

The study aims to synthetize a new functional acrylate monomer from vanillin in one step reaction. The new monomer has called by vanillin acrylate and abbreviated (VA). It was confirmed by chemical methods 1H NMR, 13C, IR and UV indicated logic results. The homopolymer has been prepared by free radical polymerization and characterized chemically and physically, the {sup 1}HNMR and IR have proofed the presence of aldehyde group in the polymer main chain. This monomer was used to synthesize three different molar concentrations of temperature responsive functional polymers with N-isopropylacrylamide via free radical polymerization by AIBN in solution. The {sup 1}H NMR was used for determination of actual mole concentration of each monomer. The aldehyde group in polymers were used as a linker for grafting with primary amine compounds by click reactions to form Schiff’s base imine compounds. The grafted copolymers were also investigated by 1H NMR and IR for structure elucidation. Gel permeation chromatography GPC was used for determination the molecular weight and polydispersity; DSC for glass temperature of solid polymers; XRD for crystallinity. UV–Vis Spectroscopy was used for the determination of phase separation or the lower critical solution temperature (Tc) of polymers solution before and after grafting, not only in deionized water but in pH 5 and pH 11. Graphical Abstract: Synthesis of new functional monomer based on vanillin in one step reaction. Monomer has been successfully polymerized by free radical polymerization using AIBN as initiator. Three different mole ratios (10, 15, 20 mol%) of copolymer with NIPAAm were prepared. All monomers and polymers have been chemically elucidated. The aldehyde functional group used as linker for primary amine compounds, the final products have been characteristics as T, pH dual responsive polymers the phase transition temperature of copolymer before and after grafting was determined by UV.vis Spectroscopy. .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Biodegradation Behaviour of Thermoplastic Starch: The Roles of Carboxylic Acids on Cassava Starch

The process of biodegradation upon modified thermoplastic starch with various types of carboxylic acids was performed via soil burial testing. As such, modification of thermoplastic starch via esterification with citric acid and ascorbic acid was made varied within the range of 1–4 by weight percentage (% w/w). As a result, after citric acid modification and ascorbic acid modification displayed higher moisture resistivity (15.04 and 20.46%) compared to thermoplastic starch, which resulted in 43.79% respectively. In addition, environmental degradation was determined by performing a biodegradation process by using compost soil. Besides, Fourier transform infrared spectroscopy and high performance liquid chromatography tests were carried out to assess the biodegradability attribute of the starch film. The findings showed that the both citric acid and ascorbic acid modifications exhibited lower rates of weight loss, consequently due to the action demonstrated by of carboxylic acids that inhibited the invasion of microbial after exposure to environmental degradation. Furthermore, the optical analysis revealed that both citric acid and ascorbic acid possessed capability to retard the invasion of microbial upon modifications observed from its rather limited formation of microbial colonies. Nevertheless, the carbonyl index portrayed lower growth rate for citric acid and ascorbic acid, in comparison to unmodified thermoplastic starch. Hence, the study concludes that the addition of carboxylic acid had reduced the rate of degradation for the thermoplastic starch, besides improving moisture resistivity.

36 MATERIALS SCIENCE↗
DOE OSTI2018

A Novel Hyperbranched Polymeric Flocculant for Waste-Water Treatment

Cationic hyperbranched oligomer poly(N-acryloyl-1,2-diaminoethane hydrochloride) (HADE) was firstly synthesized by Michael addition reaction. And then, a series of cationic flocculants poly(acrylamide/N-acryloyl-1,2-diaminoethane hydrochlorides) (PAM-HADEs) with hyperbranched structure was prepared from HADE as macro-monomer and acrylamide (AM). The structures of PAM-HADEs were characterized by Fourier transform infrared spectrometry, {sup 1}H and {sup 13}C nuclear magnetic resonance spectroscopy, gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF). And the properties were systematically evaluated by intrinsic viscosity, zeta potential and hydrodynamic radius. The mechanism of the cationic hyperbranched copolymer used in water treatment was extensively studied via a jar test in which the transmittance of the supernatant, settling time, and average floc size were used to evaluate the flocculability. Compared with the linear flocculant poly (acrylamide/liner-N-acryloyl-1,2-diaminoethane hydrochloride) (PAM-LADE), the novel hyperbranched polymeric flocculants exhibited outstanding flocculability which were reflected by shorter settlement time, high transmittance and large floc size. The primary cause that PAM-HADEs owned excellent flocculability is the more stretching configuration and less chains entanglement of PAM-HADEs in waste-water due to their hyperbranched structure compared with that of the linear PAM-LADE which exhibited curly coil configuration. On the other hand, abundant and exposed cationic terminal groups of PAM-HADEs originated from their hyperbranched structure also hint higher flocculation capacity. At optimum dosages of the polymer, the transmittance of the supernatant is less at low and high pH values, indicating that the natural pH (pH 7.29) of the suspension is the most appropriate pH for the flocculation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Comparative Study of Xylan Extracted by Sodium and Potassium Hydroxides (NaOH and KOH) from Bagasse Pulp: Characterization and Morphological Properties

Xylan is the second most abundant polysaccharide and the predominant hemicellulose component of soda bagasse pulp. The present endeavor focuses on increasing the value addition to underutilized agro-industrial residue such as bagasse. For this purpose, xylan was isolated by two conventional alkali extraction methods i.e. NaOH and KOH. The recovery rate and sugar composition of different reaction times and alkali consumptions were monitored with advanced method such as High Performance Liquid Chromatography (HPLC). The Fourier Transform Infrared Spectroscopy (FTIR) and Wide Angle X-ray spectroscopy (WAXS) were respectively employed to characterize the functional groups and Crystallinity Index (CrI) changes during the extraction process. It was explored that highest xylan recovery rates were obtained with 6% of NaOH at 120 min and 6% KOH at 45 min. The xylan morphology via WAXS was found that its structure to be amorphous. HPLC results also showed KOH had higher effectiveness than NaOH in terms of extracted xylan purity. Highest XGRs (Xylose to Glucose Ratios) were also achieved by KOH processes. Hence, this study contributes to the adequate utilization of agricultural residues, with promising potential for applications in the production of certain novel materials and chemical conversion industries.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Optimal Design of Ozone Bleaching Parameters to Approach Cellulose Nanofibers Extraction from Sugarcane Bagasse Fibers

Cellulose nanofibers (CNFs) were isolated from sugarcane bagasse (SCB) through the combination of bio-refinery, sulfur-free, and totally chlorine free (TCF) chemo-mechanical pretreatments, with a focus on the optimal design of ozone bleaching parameters based on a response surface methodology (RSM). For this purpose, the most effective parameters in ozone bleaching (temperature, time, and pulp consistency) were set between 40 and 85 °C, 60 and 360 min, and 1–5 wt%, respectively. High-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), Kappa number, and scanning electron microscopy (SEM) were used to chemically and morphologically characterize the SCB fibers. The size distribution and morphology of CNFs were also evaluated by dynamic light scattering (DLS) and transmission electron microscopy (TEM). HPLC analysis revealed that percentage of cellulose increased from 41.5 to 91.39% after chemical pretreatments. FTIR and Kappa number analyses also confirmed the successful isolation of cellulose fibers from the SCB fibers after chemical pretreatments. Furthermore, DLS results showed that the hydrodynamic diameter of the isolated cellulose fibers reduced to 268 nm by dint of ultrasonication. Additionally, TEM images confirmed the isolation of CNFs: the average diameter of cellulose fibers decreased to about 28 nm after mechanical steps and the yield of fibrillation was found to be around 99%. According to the obtained results, the applied chemo-mechanical treatment appears to be promising for green and facile isolation of CNFs.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Preparation of Chitooligosaccharide by Hydrogen Peroxide Degradation of Chitosan and Its Effect on Soybean Seed Germination

Chitooligosaccharides (COS) were prepared by hydrogen peroxide (1%) degradation of chitosan solution (3%) in dilute lactic acid at ambient temperature. The molecular weights of degraded chitosan were measured by gel permeation chromatography, and the chemical structure of resultant COS were characterized by Fourier transform infrared spectra. The decrease of chitosan Mw followed the first-order kinetics with the rate constant of 5.71 × 10{sup −7} mol/g/h. As a result, the COS with Mw of 4500 g/mol was obtained at 360 h of the reaction time and its chemical structure almost remained the same as initial chitosan. Germination ability of soybean seeds pre-soaking in COS (4500 g/mol) solution with different concentrations, particularly 0 (control), 50, 100 and 200 mg/L was investigated. Results indicated that germination rate increased significantly for all soybean seeds treated with COS compared to the control. Thus, COS prepared by this method can be potentially applied to large-scale production with reasonably low cost and used as an effective biostimulant for sustainable agriculture.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

A new method for separating first row transition metals and actinides from synthetic melt glass

A new method was developed for separating Co, Fe, and Sc from complex debris matrices using the extraction chromatography resin DGA. The activation products Co-58, Mn-54, and Sc-46 were used to characterize the separation of the synthetic melt glass solutions. In the separation scheme that was developed, Au, Co, Cu, Fe, Sc, and Ti were separated from the rest of the sample constituents. In this paper, the synthetic melt glass separation method, efficiency, recoveries, and the length of procedure will be discussed. In conclusion, batch contact adsorption studies for Na and Sc for DGA resin are discussed as well.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2018

Using Sr Resin with mixed acid matrices

Here, the quantification of radioactive material dispersed following the release of 90Sr, whether accidental or intentional, would be of high importance. Depending on the circumstances, it is possible that the contaminated materials would need to be completely digested prior to quantification. Many sample matrices require a mixture of different acids be employed to achieve total dissolution. Unfortunately, one the most common approaches for the separation of strontium, extraction chromatography with Sr Resin, has only been fully characterized in pure mineral acid solutions. This work shows that Sr Resin can be used effectively with high concentration mixtures of nitric and hydrochloric acids in the presence or absence of hydrofluoric acid, thereby potentially negating the need for conversion to a pure mineral acid matrix.

36 MATERIALS SCIENCE↗
DOE OSTI2018

An alternative separation procedure for 90 Sr age dating using DGA Resin

The likelihood of an attack by a terrorist organization using a radiological dispersal device (RDD) is much higher than that of an attack with an improvised nuclear device or true nuclear weapon, as much less technical expertise is required to build an RDD. Consequently, there has been an effort to develop methods for age-dating radiological sealed sources in recent years. One such procedure, described by Steeb et al., is used for determining the age of 90 Sr sources. That procedure utilized a rather expensive extraction chromatography resin and was based on an uncommon apparatus with limited sample capacity for the separation step. The procedure also left the Zr fraction contaminated with the radioactive 90 Y daughter nuclide. This work investigates using an alternative separation scheme that utilizes a less costly resin in a widely available column configuration and results in the isolation of 90 Sr's stable granddaughter, 90 Zr, without 90 Y contamination. This allows the zirconium quantification to be done with a mass spectrometer outside the radiological environment and increases the number of instruments capable of making the measurement, which could allow measurements to be made more quickly.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2019

Separation of thorium from uranium ore

Thorium-230 has many research applications, but there is not a commercial source of this isotope. However, since 230 Th is part of the 238 U decay chain, it can be separated from naturally occurring uranium. In this work, a novel procedure was developed to separate thorium from uranium ore, consisting of leaching, liquid–liquid extraction, precipitations and ion exchange chromatography. Here, the final product was 91.32 ± 0.77 mg of thorium with a purity of 99.5 ± 1.2 wt%. Of that, 7.65 ± 0.10 mg was 230 Th and the remainder 232 Th. The total yield of 230 Th was 71.1 ± 5.4%. Ways to improve the yield by further processing the back-extraction solution are suggested.

230Th↗
DOE OSTI2020

Inline gamma-spectrometry of fission product elements after rapid high-pressure ion chromatographic separation

Analysis of irradiated material shortly after irradiation can be non-trivial due to highly radioactive activation and fission isotopes increasing dead time in gamma-ray detection systems, often requiring a “cooling-period” between receipt of a sample and the subsequent analysis. A direct separation–detection method has been developed combining ion chromatography and inductively coupled mass spectrometry for rapid, low-level analysis of fission products; it cannot, however, detect certain short-lived species below the detection limit of the system. In this paper we report the implementation of an inline gamma-ray detector, which was added post-separation, pre-analysis, to test the quality and utility of elementally-isolated gamma-ray spectroscopy.

Inline gamma-ray detection↗
DOE OSTI2024

Uptake behavior of 73 As, 75 Se, 197m Hg, 212 Pb and 210 Po on Eichrom pre-filter resin from HCl and HNO 3

We report the extraction of 73 As, 75 Se, 197 mHg, 212 Pb and 210 Po on Eichrom pre-filter resin was studied in HCl and HNO 3 with batch uptake, kinetic and column experiments. There was significant extraction of mercury in HNO 3 and HCl, and polonium and selenium in HCl. The kinetics are sufficient to allow for retention on pre-filter columns, and separations of 73 As from 75 Se and 197 mHg, and 212 Pb from 210 Po are demonstrated. This retention is important for the development of chemical separations as pre-filter resin is commonly used alongside extraction chromatography resins but its potential for uptake of metal ions is not well characterized.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2026

Ra-226 extraction and purification from simulated uranium tailings

Growing demand for Ac-225 has outstripped current production, increasing interest in alternative production routes. Furthermore, these often rely on irradiations of Ra-226, yet Ra-226 supplies are also limited. Uranium tailings provide an abundant source of Ra-226, though separation from these complex matrices remains challenging. A laboratory-scale process was developed to recover Ra-226 from simulated U-tailings. After acid leaching, Ra remained adsorbed on refractory oxides and silicates. An additional CaCl₂ leach of the residue raised recovery to ~ 64%. Subsequent purifications, including precipitation, ion-exchange, and extraction chromatography (TK101), achieved chemical yields up to 73 ± 7%, producing 7.68 ± 0.1 µCi of high-purity Ra-226.

and nuclear chemistry↗
DOE OSTI2012

Comparison of Chloroflexus aurantiacus strain J-10-fl proteomes of cells grown chemoheterotrophically and photoheterotrophically

Chloroflexus aurantiacus J-10-fl is a thermophilic green bacterium, a filamentous anoxygenic phototroph, and the model organism of the phylum Chloroflexi. We applied high-throughput, liquid chromatography-mass spectrometry in a global quantitative proteomics investigation of C. aurantiacus cells grown under oxic (chemoorganoheterotrophically) and anoxic (photoorganoheterotrophically) redox states. Our global analysis identified 13,524 high-confidence peptides that matched to 1,286 annotated proteins, 242 of which were either uniquely identified or significantly increased in abundance under anoxic culture conditions. Fifty-three of the 242 proteins are previously characterized photosynthesis-related proteins, including chlorosome proteins, proteins involved in the bacteriochlorophyll biosynthesis, 3-hydroxypropionate (3-OHP) CO2 fixation pathway, and components of electron transport chains. The remaining 190 proteins have not previously been reported. Of these, five proteins were found to be encoded by genes from a novel operon and observed only in photoheterotrophically grown cells. These proteins candidates may prove useful in further deciphering the phototrophic physiology of C. aurantiacus and other filamentous anoxygenic phototrophs.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Adsorption of organic molecules on the highly ordered MCM-41 sorbent modified by different amounts of melamine

Thermodynamic characteristics of adsorption of organic molecules on the ordered organosilylated composite MCM-41 with grafted trimethylsilyl groups (MMet) and modified by melamine deposited on the surface were studied by inverse gas chromatography. Mole changes in the internal energy and entropy of adsorption, the dispersion and specific components of the value proportional to the Helmholtz absorption energy, and the contribution of the methyl group to the heat of adsorption were calculated from the specific retention volumes. The change in the retention volumes was established to be determined by the dispersion component of the Helmholtz energy of adsorption, whereas the energy of specific interactions remains almost unchanged. After the adsorbent surface was coated by the second and third melamine layers, the changes in −ΔU and −ΔS for adsorption of the members of the homologous series of n-alkanes are so small that lie within admissible measurement inaccuracies. This phenomenon can be explained by the regularities of alkane adsorption in slit-like pores of the supramolecular structure of melamine.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Evaluation of the Structure and Biological Activities of Condensed Tannins from Acanthus ilicifolius Linn and Their Effect on Fresh-Cut Fuji Apples

Condensed tannins (CT{sub S}) have been isolated and purified from leaves of Acanthus ilicifolius Linn. And their structures were investigated by three methods: {sup 13}C nuclear magnetic resonance ({sup 13}C NMR), reversed-phase high-performance liquid chromatography (RP-HPLC), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The results showed that the CT{sub S} were a mixture of catechin/epicatechin, galatechin/epicatechin, and amphicin/epigalin, and that the polymer chain lengths were 3-mers to 14-mers. Antityrosinase activities and antioxidant activities of the CT{sub S} from A. ilicifolius leaves were further studied. The IC{sub 50} of the CT{sub S} on mushroom tyrosinase activity was determined to be 19.7 ± 0.13 μg/mL, and inhibition type analyses indicated that the CT{sub S} were mixed type inhibitors and their inhibition CT{sub S} was reversible. The CT{sub S} from A. ilicifolius leaves also exhibited potential antioxidant activity. The IC{sub 50} of DPPH and ABTS scavenging activities were 104 ± 0.894 μg/mL and 86 ± 0.616 μg/mL, respectively. And the FRAP value was 758.28 ± 2.42 mg AAE/g. In addition, we found that the CT{sub S} from A. ilicifolius leaves had an excellent effect on preserving the quality of fresh-cut apples by preventing apples from browning through reducing polyphenol oxidase activities in apples.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Cloning, Purification, and Characterization of Recombinant Thermostable β-Xylanase Tnap-0700 from Thermotoga naphthophila

The gene of a β-xylanase (Tnap-0700) was cloned from a hyperthermophilic Thermotoga naphthophila strain ATCC BAA-489 and expressed in Escherichia coli BL21 (DE3) via pET-21a (+) as an expression vector. The growth steps were upgraded for highest β-xylanase expression via several factors, for example, IPTG concentration, time of induction, pH, and temperature. The pH and temperature optima for the extreme expression of β-xylanase were 7.0 pH and 37 °C, correspondingly. Recombinant enzyme purified by heat treatment process, then later by immobilized metal ion affinity chromatography. Molecular mass of the purified β-xylanase was 38 kDa observed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme was stable at room temperature for 30 days. It exhibited high stability over wide series of temperature 50–90 °C and pH 4.0–9.0 upon the addition of 1 mM Ca{sup +2} and reduced in the existence of Cu{sup +2} and EDTA. The addition of about 10–30% different organic solvents have no considerable effect on enzyme. However, SDSF and urea acting as an inhibitor leads to decrease in the enzyme activity. The β-xylanase enzyme was active to hydrolyze xylan from beechwood forming xylose. Thermostable β-xylanase causes the breakdown of complex carbohydrates into monosaccharide components. This thermostable β-xylanase revealed remarkable properties, which make it an encouraging candidate for various industrial applications especially in the alteration of renewable biomaterials into ethanol production, and biofuels from lignocellulosics has acknowledged much devotion subsequently in the last decade.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Influence of ABCB1 polymorphisms on the pharmacokinetics and toxicity of lenalidomide in patients with multiple myeloma

Individual diversity in plasma concentrations of lenalidomide occurs despite dosage modifications based on creatinine clearance (CCr), which can lead to unexpected toxicity. We have previously identified a cutoff value of area under the concentration–time curve (AUC{sub 0–24}) for lenalidomide to avoid severe toxicity. Here, we investigated the association between ABCB1 polymorphisms and pharmacokinetics of lenalidomide in patients with multiple myeloma (MM) treated with lenalidomide and dexamethasone. Plasma concentrations of lenalidomide were analyzed using liquid chromatography–tandem mass spectrometry. Genotyping for ABCB1 1236C>T, 2677G>A/T, and 3435C>T polymorphisms was performed, and the effects of ABCB1 polymorphisms on AUC{sub 0–24} for lenalidomide were compared in 36 patients with MM who were administered lenalidomide according to the drug label based on CCr. Genotyping analysis showed that although there were no differences in AUC{sub 0–24} in 1236C>T and 2677G>A/T polymorphisms. AUC{sub 0–24} was significantly higher in patients with the T allele of 3435C>T (n = 15) than in those without (n = 21) (median 6324.6 ng h/mL vs. 2857.4 ng h/mL, p = 0.028). The AUC{sub 0–24} value exceeded the aforementioned cutoff value in 95% of the patients with the T allele of 3435C>T but in 60% with C/C genotype (p = 0.013). Multivariate logistic analysis confirmed the significance of T allele of ABCB1 3435C>T as a factor due to which the AUC{sub 0–24} cutoff value was exceeded (hazard ratio of 15.0, p = 0.019). We show that lenalidomide pharmacokinetics is influenced by the ABCB1 3435C>T polymorphism, which could be useful to individualize dosage design and reduce unexpected toxicity.

62 RADIOLOGY AND NUCLEAR MEDICINE↗