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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Effect of substituting iron on structural, thermal and dielectric properties of lithium borate glasses

Highlights: • There is increase in NBOs with iron content. • FTIR spectra supported the results predicted by density. • Glass stability has been examined. • Iron shows “blocking effect” on migration of mobile ions. • Internal Circuit varies with temperature and composition. - Abstract: Glasses with composition xFe{sub 2}O{sub 3}·(30 − x)Li{sub 2}O·70B{sub 2}O{sub 3} (x = 0, 2, 5, 7 and 10 mol%) were prepared via melt-quenching technique and their physical, thermal and dielectric properties are discussed. XRD was carried out to confirm the amorphous nature of prepared glasses. Density (ρ) and molar volume (V{sub m}) were found to increase with increase in Fe{sub 2}O{sub 3} content. Infrared absorption spectra depicted that Fe{sub 2}O{sub 3} is acting as a network modifier. DTA has been carried out to determine glass transition temperature (T{sub g}) and crystallization temperature (T{sub x}). Electrical properties have been studied using impedance spectroscopy and dc conductivity. The dc conductivity decreases and activation energy increases on replacing Li{sup +} ions with Fe{sup 3+}. The impedance measurements reveal that the total conductivity obeys Jonscher’s power law. Study of the equivalent circuit analysis up to a temperature of 523 K shows a significant change in the equivalent circuitry with change in temperature and composition.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Growth and characterization of a third order nonlinear optical single crystal: Ethylenediamine-4-nitrophenolate monohydrate

Highlights: • EDA4NPH crystal possesses negative nonlinear refractive index. • The crystal exhibits high third-order NLO susceptibility. • Wide transparency of the crystal makes it suitable for NLO applications. • Dielectric studies substantiate the suitability for electro-optic applications. • The crystal possesses suitable mechanical strength for device fabrication. - Abstract: Bulk crystals of the charge-transfer complex, ethylenediamine-4-nitrophenolate monohydrate, were grown by slow solvent evaporation method from aqueous solution at room temperature. The X-ray diffraction measurements showed that the crystal belongs to centrosymmetric space group C2/c of monoclinic system. The functional groups in the complex were identified using FTIR, FTRaman and FTNMR analyses. The Z-scan measurements revealed the negative nonlinear refractive index of the crystal. The nonlinear absorption coefficient and third order nonlinear optical susceptibility calculated from the measurements were −3.5823 × 10{sup −3} cm/W and 2.3762 × 10{sup −6} esu respectively. The crystal was shown to be highly transparent above 366 nm by UV–vis spectroscopy and a yellow fluorescence was observed from PL spectrum. The TG–DTA and DSC analyses showed that the crystal is thermally stable up to 117.4 °C. The crystals were characterized by dielectric, etching and microhardness studies.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Heteropolytungstate nanoparticles: Microemulsion-mediated preparation and investigation of their catalytic activity in the epoxidation of olefins

Highlights: • Keggin type Q{sub 3}PW{sub 12}O{sub 40} nanoparticles were synthesized by using microemulsion system. • The nanoparticles have uniform size of about 25 nm and spherical morphologies. • The prepared nanoparticles act as reusable catalyst in the epoxidation of olefins with H{sub 2}O{sub 2}. - Abstract: Keggin type Q{sub 3}PW{sub 12}O{sub 40} nanoparticles (Q = cetyltrimethylammonium cation) were synthesized in water-in-oil (w/o) microemulsion consisted of water/cetyltrimethylammonium bromide/n-butanol/isooctane. Reaction of Na{sub 2}WO{sub 4}, Na{sub 2}HPO{sub 4} and hydrochloric acid within water containing nanoreactors of reverse micelles resulted in the preparation of Q{sub 3}PW{sub 12}O{sub 40} nanoparticles. The resultant nanoparticles were analyzed by physicochemical methods such as FT-IR spectroscopy, X-ray diffraction, energy-dispersive X-ray analysis, thermogravimetric analyses (TGA-DTA), scanning and transmission electron microscopy and atomic force microscopy which show nearly uniform spherical nanoparticles with size of about 15 nm. Finally, catalytic activity of the Q{sub 3}PW{sub 12}O{sub 40} nanoparticles was examined in the epoxidation of olefins with H{sub 2}O{sub 2}. The prepared nanoparticles acted as recoverable and reusable catalyst in the epoxidation of olefins with H{sub 2}O{sub 2}.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Photocatalytic activity of ZnO nanoparticles with optimization of defects

Graphical abstract: Systematic scheme for photocatalytic activity. Pristine and air quenched ZnO nanoparticles were effectively synthesized by simple combustion method and effectively used as photocatalyst for photodegradtion of methyl orange dye. It was observed that air quenched ZnO nanoparticles shows the better properties as compared to pristine ZnO. The complete degradation of dye was observed in 150 min. - Highlights: • Pristine and air quenched ZnO nanoparticles were synthesized by simple combustion method. • Synthesized ZnO for air quenched ZnO has better optoelectronic properties. • ZnO nanoparticles for air quenched ZnO exhibiting complete photodegradation of Methyl Orange dye under UV irradiation. • Photocatalytic activities for all the samples were observed in 150 min. - Abstract: Tuning of defect levels is the major concern for the application of ZnO nanoparticles. These nanoparticles with different defect concentration were prepared by simple combustion method at 700 °C and subsequent quenching in air. The catalyst was characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM), UV–vis spectroscopy measurements. XRD reveals that the cell volume increased with large temperature difference between 700 °C and quenched media. FTIR confirmed that the vibrational frequencies shifted from 519 cm{sup −1} to 535 cm{sup −1} point out the role of quenching defects. FESEM shows the size is of the order of 20–45 nm and found irregular distribution of grain boundaries in the quenched induced defects. Different morphology plays a major role in the enhancement of photocatalytic efficiency of synthesized nanoparticles. PL intensity indicates more oxygen vacancies for air quenched ZnO whereas; DTA study demonstrates that the synthesized ZnO is thermally stable. Kinetics study confirmed the photodegradation of methyl orange (MO) dye using this photocatalyst follows first order rate constant. It exhibits the complete degradation of dye only in 150 min under UV irradiation. Kinetic study revealed the rate constant of nanoparticles is 0.0165 min{sup −1}. Air quenched sample showed the higher intensity of defect band as compared to pristine ZnO.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Structural and photocatalytic examination of CoMoO4 nanopowders synthesized by GNP method

Highlights: • Synthesis of CoMoO{sub 4} nanoparticles in a simple, quick, and inexpensive way, by using a glycine nitrate procedure (GNP). • Two different crystal structures of CoMoO{sub 4}, α and β, was confirmed by X-ray diffraction. • BET analysis confirmed significant specific surface areas of CoMoO{sub 4} nanopowder. • CoMoO{sub 4} nanopowders can be promising solutions in photocatalytic processes toward green chemistry and sustainable development. - Abstract: The synthesis route by solution combustion, a glycine nitrate procedure (GNP) of CoMoO{sub 4} nanopowders by a glycine as a fuel and as a complexant was examined concerning the photocatalytic aspects and powder characteristics. The synthesized samples were investigated by differential thermal analysis (DTA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Ultraviolet-Visible (UV/Vis) spectroscopy and nitrogen adsorption method. In this work, we presented a simple and effective method for controlling the composition and morphology of CoMoO{sub 4}. A single-phase α and β crystalline form of CoMoO{sub 4} compound was confirmed by X-ray diffraction (XRD). The photocatalytic activity of CoMoO{sub 4} nanopowders was estimated by the photocatalytic degradation of crystal violet in aqueous solution. In addition, the obtained specific CoMoO{sub 4} nanopowder demonstrated acceptable specific surface area, which can be of particular importance for the photocatalytic processes.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Fabrication and characterization of electrospun single-crystal lead manganese borate nanofibers

Highlights: • Single crystal PbMnBO4 nanofibers were successfully fabricated by electrospinning process. • The PbMnBO4 nanofibers synthesized for the first time and unprecedented in the literature. • Characterization of PbMnBO{sub 4} nanofibers in mineralogical, optical and thermal properties was revealed. • The nanofibers exhibit single crystalline features with an average size between 120 and 250 nm. • These nanofibers can be used in optic or photonic fields as a flexible sensor due to its nonlinear and ferromagnetic properties. - Abstract: Anhydrous borate compounds are important materials in optical applications as nonlinear optical materials (NLO), due to the presence of structural B{sub x}O{sub y} subunits. Herein, lead manganese borate (PbMnBO{sub 4}) nanofibers have been firstly fabricated via a facile approach using a simple and inexpensive electrospinning technique. All of the synthesized samples were analyzed with X-Ray Diffractometer (XRD), Transmission Electron Microscope (TEM), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), and Ultraviolet-visible Spectroscopy (UV–vis) method. In addition, they were thermally analyzed with Thermal Gravimetric and Differential Thermal Analyzer and TG-DTA diagrams were discussed in detail. All of the characterization results showed that the obtained PbMnBO{sub 4} nanostructures have nanofiber structures and good crystalline features. PbMnBO{sub 4} nanofiber synthesized for the first time and unprecedented in the literature is promising absorber materials for nonlinear optic applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Nickel doped graphitic carbon nitride nanosheets and its application for dye degradation by chemical catalysis

Highlights: • Nickel doped Graphitic carbon nitride (GCN) was synthesized chemically. • Mott-Schottky was done to calculate the flat band potentials and donor densities of pure and doped samples. • Toxic Methyl Orange dye was degraded efficiently by doped samples in the presence of NaBH{sub 4} accompanied by hydrogen evolution. • Enhancement of catalytic activity with increasing doping concentration was studied in presence of varying amount of NaBH{sub 4}. • A plausible mechanism for catalytic degradation was discussed in details. - Abstract: A facile synthesis of transition metal-nickel doped graphitic carbon nitride (NiGCN) nanosheets with varying doping concentrations has been reported. X-Ray diffraction and Fourier transformed infrared spectroscopic study were performed to analyse the structural phase formation and different bonds present in the samples, whereas, field emission and transmission electron microscopic study provided the morphological information. The thermal stability of the samples was measured from the TG-DTA analysis. Photoluminescence spectroscopy was performed to elucidate the emissive property of the samples. The flat band potential of the samples was measured by Mott-Schottky analysis. First principle study was carried out to delineate the probable doping site of the Ni atom along with the effect of doping on the pure material. The samples were effectively utilized to degrade toxic methyl orange (MO) dye from water in the presence of sodium borohydride (NaBH{sub 4}) without exploiting any visible light source. The plausible catalysis mechanism following a series of several chemical reactions has been discussed in details.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2020

A large-scale, agent-based simulation of metropolitan freight movements with passenger and freight market interactions

This study summarizes the first stage in the implementation of an agent-based freight modeling system that has a global representation of agents and detailed modeling of a large-scale transportation network. The model is used to evaluate the transportation and energy impacts of goods movement across urban and national scales. The framework is implemented within POLARIS, a C++-based Planning and Operations Language for Agent-based Regional Integrated Simulation, which consists of an activity-based modeling (ABM) and dynamic traffic assignment (DTA) system that has robust features for passenger travel. This platform provides a tool to model interactions among consumers, producers, and the transportation system. The main objective of this initial implementation is to implement a freight model within POLARIS following an agent-based paradigm with behavioral and simulation methods. This paper presents the initial framework and illustrates the application of the model. Building upon earlier works, a parcel location assignment algorithm for business establishments in the population is documented, along with a method for estimating establishment production and consumption volumes. In addition to population generation, other features of the model include push-pull supply chains, multimodal path choice, choice of transportation logistics node, and dynamic traffic assignment. A module with e-commerce supply and demand was also developed to analyze the effects of e-commerce delivery on last-mile energy use and congestion.

agent-based freight↗
DOE OSTI2020

Formation and energetics of amorphous rare earth (RE) carbonates in the RE 2 O 3 –CO 2 –H 2 O system

Amorphous materials are of interest in the genesis of crystalline solids. They are often the first to precipitate from supersaturated solutions and are in the nanometer size range, transforming into a nanocrystalline metastable phase, and then to thermodynamically stable phases. One must seek knowledge of the composition, structure, thermodynamics, kinetics, and reaction pathways that relate the amorphous and crystalline phases. The subject of this study is the amorphous phases in the system RE 2 O 3 -CO 2 –H 2 O (RE- La, Nd, Dy,Yb). They were synthesized via direct precipitation and urea hydrolysis, and characterized by powder XRD, DTA with mass spectrometric analysis of the evolved gases. Phases have the non-stoichiometric composition RE 2 O 3 ·xCO 2 ·yH 2 O (1 < x < 3, 3 < y <7), which is different from that of crystalline simple carbonates and hydroxycarbonates. Thus we consider them to be amorphous precursors, rather than amorphous carbonates. High temperature oxide melt solution calorimetry in molten sodium molybdate solvent was used to derive their enthalpies of formation from oxides and elements. Increase of energetic stability per mole of RE 2 O 3 compounds occurs in the order: RE 2 O 3 → 2RE(OH)3→ 2REO(OH) → RE 2 O 2 CO 3 → Amorphous precursor → 2(REOHCO 3 ) → RE 2 (CO 3 ) 3 ·yH 2 O. We calculated the enthalpies of possible transformations of amorphous precursors to crystalline phases and conclude that thermodynamics determines the dependence of the crystallizing products on the temperature and partial pressure of CO 2 and H 2 O. Amorphous precursors are clearly intermediate in the synthesis, and ternary phases containing both H 2 O and CO 2 compete with each other in terms of thermodynamic stability. The energy landscape obtained here will allow one to directly synthesize specific products and control their functionality.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Hydrogen-Bonded Organic Frameworks: A Rising Class of Porous Molecular Materials

Hydrogen-bonded organic frameworks (HOFs) are a class of porous molecular materials that rely on the assembly of organic building blocks by means of hydrogen-bonding interactions to form two-dimensional (2D) and three-dimensional (3D) crystalline networks. The reversible nature of the hydrogen-bond formation endows HOFs with the attributes of solution processability and simple regeneration. High-quality single crystals of HOFs can be grown easily for unambiguous superstructure determination by single-crystal X-ray diffraction, which is crucial for the elucidation of superstructure–property relationships. During the past decade, considerable progress has been achieved in realizing stable HOFs with permanent porosities by focusing on the design of molecular building blocks in order to introduce rigidity, auxiliary [π···π] interactions, and interpenetration of their frameworks to sustain the extended networks. The applications of HOFs are far-reaching, spanning catalysis, energy, and biomedical products as well as the storage and separation of fine chemicals. In this paper, we, first of all, provide an overview of the chronological development of HOFs, starting from the seminal work by Marsh and Duchamp in 1969 on the crystal superstructure of the hydrogen-bonded networks of trimesic acid. We identify the development of novel hydrogen-bonding motifs such as diaminotriazine (DTA), the introduction of the concept of molecular tectonics, and the establishment of permanent porosity in HOFs as being some of the milestones, which incentivized the current burgeoning research endeavors on developing HOFs as multifunctional materials. This Account is focused primarily on surveying the strategies for constructing porous 3D HOFs based on organic building blocks with peripheral carboxyl groups. These strategies are presented in the following categories: (1) the polycatenation of 2D networks by trigonal building blocks to form global 3D frameworks, (2) the utilization of building blocks with 3D geometries—tetrahedral and trigonal prismatic—that are predisposed to form 3D networks, and (3) the docking by shape-fitting of geometrically labile building blocks. We emphasize how the molecular geometry of the building blocks plays an important role in modulating the superstructures of extended frameworks so as to address specific applications. Recognizing that the in silico design of HOFs is the ultimate goal of researchers in this field, we also discuss the recent advances in superstructure prediction that lead to the formation of porous supramolecular crystals and assess the complications in implementing computational methods for HOFs with complex superstructures. We hope this Account will inspire the development of new supramolecular designs and creative approaches to crystal engineering that aid and abet the assembly of multifunctional HOFs with customizable properties.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Decacyclene Trianhydride at Functional Interfaces: An Ideal Electron Acceptor Material for Organic Electronics

We report the interface energetics of decacyclene trianhydride (DTA) monolayers on top of two distinct model surfaces, namely, Au(111) and Ag(111). On the latter, combined valence band photoemission and X-ray absorption measurements that access the occupied and unoccupied molecular orbitals, respectively, reveal that electron transfer from substrate to surface sets in. Moreover, density functional theory calculations confirm our experimental findings and provide an understanding not only of the photoemission and X-ray absorption spectral features of this promising organic semiconductor but also of the fingerprints associated with the interface charge transfer.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Highly Efficient Iodine Capture by Layered Double Hydroxides Intercalated with Polysulfides

We demonstrate strong iodine (I-2) vapor adsorption using Mg/Al layered double hydroxide (MgAl-LDH) nanocomposites intercalated with polysulfide (S-x(2-)) groups (S-x-LDH, x = 2, 4, 6). The as-prepared LDH/polysulfide hybrid materials display highly efficient iodine capture resulting from the reducing property of the intercalated polysulfides. During adsorption, the I-2 molecules are reduced to I-3(-) anions by the intercalated [S-x](2-) groups that simultaneously are oxidized to form S8. In addition to the chemical adsorption, additional molecular I-2 is physically captured by the LDH composites. As a result of these parallel processes, and despite their very low BET surface areas, the iodine capture capacities of S-2-LDH, S-4-LDH, and S-6-LDH are similar to 1.32, 1.52, and 1.43 g/g, respectively, with a maximum adsorption of 152% (wt %). Thermogravimetric and differential thermal analysis (TG-DTA), energy dispersive X-ray spectroscopy (EDS), and temperature-variable powder X-ray diffraction (XRD) measurements show the resulting I-3(-) ions that intercalated into the LDH gallery have high thermal stability (>= 350 degrees C). The excellent iodine adsorption performance combined with the facile preparation points to the S-x-LDH systems as potential superior materials for adsorption of radioactive iodine, a waste product of the nuclear power industry.

Ma, Shulan↗
DOE OSTI2013

Precipitation method for barium metaborate (BaB{sub 2}O{sub 4}) synthesis from borax solution

In this study, barium metaborate (BaB{sub 2}O{sub 4}, BMB) synthesis from the borax solution was carried out. BMB currently is used in production of ceramic glazes, luminophors, oxide cathodes as well as additives to pigments for aqueous emulsion paints and also β−BaB{sub 2}O{sub 4} single crystals are the best candidate for fabrication of solid-state UV lasers operating at a wavelength of 200 nm due to excellent nonlinear optical properties. In the present study, synthesis was carried out from the borax solution (Na{sub 2}B{sub 4}O{sub 7⋅}10H{sub 2}O, BDH) and barium chloride (BaCI{sub 2⋅}2H{sub 2}O, Ba) in the glass-batch reactor with stirring. The effect of, times (5-15 min), molar ratio [stoich.ration (1.0:2.0), 1.25:2.0, 1.5:2.0, 2.5:2:0, 3.0:2.0, 3.5:2.0,4.0:2.0, 5.0:2.0] and also crystallization time (2-6 hour) on the BMB yield (%) was investigated at 80 °C reaction temperature. It is found that, BMB precipitation synthesis with 90 % yield can be performed from 0.50 molar ration (BDH:Ba), under 80 °C, 15 minute, and 6 hours crystallization time. The structural properties of BMB powders were characterized by using XRD, FT-IR and DTA-TG instrumental analysis technique.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Effect of TiO{sub 2} additives to the sintering of Y{sub 2}O{sub 3}

The effect of sintering additive on the microstructure development of yttrium oxide was investigated. Different combinations of yttrium oxide with TiO{sub 2} were used as x-ray diffraction, differential thermal analysis (DTA) were sintering additive. The investigated and microstructure of resulting compacts were characterized by, using scanning electron microscopy, porosity and sintering density for all compacting samples sintered at different sintering temperature under static air.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Crystal growth, structure analysis and characterisation of 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid single crystal

Single crystal of dielectric material 2 - (1, 3 - dioxoisoindolin - 2 - yl) acetic acid has been grown by slow evaporation solution growth method. The grown crystal was harvested in 25 days. The crystal structure was analyzed by Single crystal X - ray diffraction. UV-vis-NIR analysis was performed to examine the optical property of the grown crystal. The thermal property of the grown crystal was studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The dielectric measurements were carried out and the dielectric constant was calculated and plotted at all frequencies.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Growth, structural and optical characterization of L-histidine 4-nitrophenolate (LHPNP) single crystals for NLO applications

Using slow evaporation solution growth technique, single crystals of L-histidine-4-nitro phenolate has been grown from the solution. Structural analyses were carried out by powder x-ray diffraction, FT-Raman, Fourier Transform Infrared and Nuclear Magnetic Resonance spectral methods to conform the grown crystals. Thermal stability of the grown crystals was studied by thermo-gravimetric (TG) and differential thermal analyses (DTA). UV-Vis spectral analysis has been carried out to find the transparency of the grown crystal. Nonlinear optical property has been confirmed by Kurtz powder technique. The PL measurements were carried out in Perkin Elmer LS 55 Luminescence spectrometer using 410 nm as excitation wavelength. The observed properties have confirmed that the grown crystal is suitable for nonlinear optical applications.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Growth and characterization of nonlinear optical single crystal: Nicotinic L-tartaric

Nonlinear optical single crystals were grown from Nicotinic and L-Tartaric acid by slow evaporation technique at room temperature. Structure of the grown crystal was confirmed by single crystal X-ray diffraction studies, The crystallinity of the Nicotinic L-Tartaric (NLT) crystals was confirmed from the powder XRD pattern. The transparent range and cut off wavelength of the grown crystal was studied by the UV–Vis spectroscopic analysis.The thermal stability of the crystal was studied by TG-DTA. The second harmonic generation (SHG) efficiency of NLT was confirmed by Kurtz Perry technique.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Crystalline perfection, birefringence and laser damage threshold properties of piperidinium p-hydroxybenzoate

Piperidinium p-hydroxybenzoate (PPHB) crystal was grown by slow evaporation method. Single crystal X-ray diffraction studies confirm that PPHB crystallizes in monoclinic crystal system with noncentrosymmetric space group Cc. The crystalline perfection of the grown crystal was evaluated by using high resolution X-ray diffractometry. UV-Visible transmission and birefringence studies were employed on the grown PPHB crystal. The laser induced damage threshold value was estimated using Nd:YAG laser. Thermal behavior of PPHB crystal has been investigated by TG-DTA analyses. Etching studies have been performed to assess the growth pattern of PPHB crystal.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗