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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 1,801 records · Page 100
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

A Novel Packaging Film from Cassava Starch and Natural Rubber

Currently, there is an environmental pollution problem generated in part by packaging materials produced from non-biodegradable synthetic polymers made from petroleum. However, these can be replaced with biodegradable materials made from cassava starch (CS) and natural rubber (NR). In the work described, a novel biopolymer film was obtained from the CS and NR using glycerol (GE) as a plasticizer in a water-based system. The physical properties of an 95/5 CS/NR blend films with the addition of NR and with varying GE contents were studied based on their swelling ratio, moisture content, moisture absorption, mechanical properties and biodegradability in soil. The results showed that the moisture content and moisture absorption tended to be directly proportional to the GE content, while the moisture content and moisture absorption of the sample decreased as a function of the NR content. The swelling ratio of the 95/5 CS/NR blend slightly decreased as a function of the NR and GE content. Surprisingly, the best swelling ratio of 350% was found at 10% NR. The elongation at break of the CS/NR blend was improved by the addition of GE. The contact angle of the 95/5 CS/NR blend decreased as a function of the GE. With increased NR in the composite, an increasing, trend in the contact angle was found. Further, the 95/5 CS/NR blend exhibited good transparency when it was applied as a coating to delay the ripening of bananas, the results were positive. Moreover, the film showed decomposition well in natural soil.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

RF Plasma Polymerization of Orange Oil and Characterization of the Polymer Thin Films

The present study describes an environmentally friendly approach to fabricate hydrocarbon-rich polymer thin films from a bio-renewable precursor, orange oil, cold extracted from orange peels using radio frequency plasma polymerization. The polymer thin films fabricated at different RF power level (10–75 W) were characterized with variable angle spectroscopic ellipsometry, UV–visible spectroscopy, Fourier transform infrared spectroscopy and atomic force microscopy. Optical characterization showed that independent of deposition power films exhibited good transparency (~ 90%) in the visible region and a refractive index of 1.55 at 500 nm. The optical band gap measured around 3.60 eV and falls within the insulating region. The atomic force microscopic images revealed that the surface is pinhole-free in nature and smooth at nanoscale, with average surface roughness dependent on the deposition power. Film hardness increased from 0.50 to 0.78 GPa as applied power increased from 10 to 75 W.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Properties of Poly(Vinyl Alcohol)/Chitosan Nanocomposite Films Reinforced with Oil Palm Empty Fruit Bunch Amorphous Lignocellulose Nanofibers

The objective of this study was to investigate the properties of poly(vinyl alcohol)/chitosan nanocomposite films reinforced with different concentration of amorphous LCNFs. The properties analyzed were morphological, physical, chemical, thermal, biological, and mechanical characteristics. Oil palm empty fruit bunch LCNFs obtained from multi-mechanical stages were more dominated by amorphous region than crystalline part. Varied film thickness, swelling degree, and transparency of PVA/chitosan nanocomposite films reinforced with amorphous part were produced. Aggregated LCNFs, which reinforced PVA/chitosan polymer blends, resulted in irregular, rough, and uneven external surfaces as well as protrusions. Based on XRD analysis, there were two or three imperative peaks that indicated the presence of crystalline states. The increase in LCNFs concentration above 0.5% to PVA/chitosan polymer blends led to the decrease in crystallinity index of the films. A noticeable alteration of FTIR spectra, which included wavenumber and intensity, was obviously observed along with the inclusion of amorphous LCNFs. That indicated that a good miscibility between amorphous LCNFs and PVA/chitosan polymer blend generated chemical interaction of those polymers during physical blending. Reinforcement of PVA/chitosan polymer blends with amorphous LCNFs influenced the changes of T{sub g} (glass transition temperature), T{sub m} (melting point temperature), and T{sub max} (maximum degradation temperature). Three thermal phases of PVA/chitosan/LCNFs nanocomposite films were also observed, including absorbed moisture evaporation, PVA and chitosan polymer backbone structural degradation and LCNFs pyrolysis, and by-products degradation of these polymers. The addition of LCNFs 0.5% had the highest tensile strength and the addition of LCNFs above 0.5% decreased the strength. The incorporation of OPEFB LCNFs did not show anti-microbial and anti-fungal properties of the films. The addition of amorphous LCNFs 0.5% into PVA/chitosan polymer blends resulted in regular and smooth external surfaces, enhanced tensile strength, increased crystallinity index, and enhanced thermal stability of the films.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Photo-Stabilisation and UV Blocking Efficacy of Coated Macro and Nano-Rutile Titanium Dioxide Particles in Paints and Coatings

Surface treated macro and nanoparticle TiO{sub 2} samples have been prepared, characterised and their efficiency as UV blockers evaluated in clear coatings and paints. The particle size of the ‘base’ TiO{sub 2} has been optimised to block UV radiation and the surface treatment developed to deactivate the photocatalytic activity of the surface of the TiO{sub 2} particles. The resultant UV blockers have been evaluated in both solvent and water-based clear coatings. Nanoparticle TiO{sub 2} has been prepared from ‘seed’ and the particle size was controlled by calcination. It was found that the choice of particle size is a compromise between UVA absorption, UVB absorption, visible transmission and photoactivity. It has been demonstrated that TiO{sub 2} with a crystallite size of 25 nm yields a product with the optimum properties. A range of dispersants was successfully used to disperse and mill the TiO{sub 2}. Both organic and inorganic dispersants were used; 2-amino-2-methyl-1-propanol and 1-amino-2-propanol (MIPA) and P{sub 2}O{sub 5} and Na{sub 2}SiO{sub 3} respectively. The surface of the nano-TiO{sub 2} was coated with mixed oxides of silicon, aluminium, zirconium and phosphorous. Addition of the resultant coated nano-rutiles to an Isocyanate Acrylic clear coating prolonged the lifetime of that coating compared to the blank. Generally, a surface treatment based on SiO{sub 2}, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5} was more successful than one based on ZrO{sub 2}, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5}. Higher addition levels of the surface treatment were beneficial for protecting the polymeric coating. The UV blocker products were also evaluated in a water-based acrylic, first a water-based dispersion of the UV blocker was prepared before addition to the acrylic. The dispersions and resultant acrylic thin films were evaluated using UV/Vis spectroscopy and durability assessed. The ratio of absorbance at 300:500 nm for the water-based dispersion was shown to be a good predictor of both the transparency of the resultant acrylic thin film and the durability of that film, in terms of weight loss. Macro grade titanium dioxide pigments were also prepared and coated with treatments of silica, alumina and siloxane and their photo-stabilising activity in alkyd paint film assessed and found to be directly related to the electron–hole pair mobility and trapping as determined by micro-wave spectroscopy.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Nanocomposites Based on Poly(lactic acid) and Bacterial Cellulose Acetylated by an α-Hydroxyacid Catalyzed Route

Poly(lactic acid) (PLA) nanocomposite films reinforced with acetylated bacterial cellulose nanoribbons were prepared by solvent casting. Acetylation of bacterial cellulose (BC) was performed by an innovative and sustainable direct solvent-free route catalyzed by citric acid. The effect of derivatization and its extent on the morphological, optical, thermal and mechanical properties of the nanocomposites was analyzed. Data collected from the above studies showed that acetylation of BC nanoribbons clearly improved the nanofibers dispersion in the PLA matrix with respect to unmodified BC, which in turn resulted in increased transparency and mechanical properties of the nanocomposites produced.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Effect of Natural Glyceryl Tributyrate as Plasticizer and Compatibilizer on the Performance of Bio-Based Polylactic Acid/poly(3-hydroxybutyrate) Blends

Bio-based poly(lactic acid)/poly(3-hydroxybutyrate) (PLA/PHB) films were melt-blended with a natural hydrophobic plasticizer (glyceryl tributyrate, TB) at three different concentrations (10, 15 and 20% by weight per 100 parts of the blends) to study the effect of TB on the final properties of the materials. The pursued aim was to obtain a material with potential use in the packaging industry. Two different PLA/PHB ratios were used, 70/30 and 60/40, respectively. A full characterization of the developed blends was carried out, including the morphological, thermal, mechanical and barrier properties. The thermal test revealed the immiscibility between PLA and PHB by showing two glass transition temperatures for the blends and biphasic melt. Mechanical tests showed the increased in the elongation at break as the plasticizer content in films increased. The incorporation of PHB crystals in the PLA matrix displayed an improvement in the water barrier properties of materials. Finally, formulations PLA/PHB-TB with 15 wt% of plasticizer presented the best combination of properties suitable for the intended use in films manufacturing, showing toughness and ductility, good water barrier properties and transparency with slightly amber color.

36 MATERIALS SCIENCE↗
DOE OSTI2019

A Review on Material and Antimicrobial Properties of Soy Protein Isolate Film

In twenty first century, there is an increasing demand for packed food which requires packaging films. At present, these packaging films are processed from synthetic polymers such as polyethylene, polypropylene and many other synthetic polymers. But we need to start using soy protein as sustainable antimicrobial film that can be used for packaging purposes. There is abundance and high availability of soy protein isolate (SPI) as by-product from industries, such as food processing or biodiesel production. Soy based films from renewable resources can offer a more suitable alternative to films fabricated from synthetic materials. Soy based films in presence of additives such as acidic compounds, nanoparticles and natural compounds have good mechanical properties and are transparent in nature. In addition, soy based film in presence of 2,2-diphenyl-2-hydroxyethanoic acid and copper phosphate can give lotus-like structure as evidenced from morphological studies. Also the manufacturing process (solution casting and compression molding) of SPI film in the presence or absence of additives is very easy and commercially feasible. It is worth noting that SPI films can be produced at laboratory scale by both casting and compression molding methods. In this review paper, we have focused on the material properties as well as antimicrobial properties of SPI based films in the presence of natural and synthetic additives as reported in the last 20 years.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2019

Highly Size-Selective Water-Insoluble Cross-Linked Carboxymethyl Cellulose Membranes

Carboxymethyl cellulose (CMC) membranes have strong potential for application as molecular-scale separators. For this study, stable CMC membranes were fabricated with aluminum chloride (AlCl{sub 3}) and iron(III) chloride (FeCl{sub 3}) serving as cross-linkers. The resulting CMC-Al and CMC-Fe membranes were optically transparent and water-insoluble with sufficient mechanical strength for practical applications. The water permeation flux through the membranes was directly proportional to the operating pressure. With just a 10-fold increase in the molecular weight from 60 Da (urea) to 604 Da (bordeaux S), the effective diffusion coefficient (D{sub eff}) of the CMC-Al membrane increased 56-fold, and that of the CMC-Fe membrane increased 3500-fold. This significant correlation between D{sub eff} on molecular size indicated that the sizes of the mass transfer channels through the membrane were strictly monodisperse, in the range of molecular sizes that were tested.

36 MATERIALS SCIENCE↗
DOE OSTI2019

A Simple Approach for the Synthesis of Cellulose Nanofiber Reinforced Chitosan/PVP Bio Nanocomposite Film for Packaging

The development of chitosan-based food packaging film has been increasing due to its wider availability, biodegradability, low-cost, and renewability. The purpose of this study was to develop cellulose nanofibers (CNFs) reinforced Chitosan/PVP(CHP) green bio nanocomposite film by solvent casting method with enhanced barrier and mechanical property. CNFs of dimension 9–11 nm and 100–200 nm were extracted from jute fibers by directly treating it with HNO{sub 3}–NaNO{sub 2} mixture. Bio nanocomposite films were synthesized with various concentrations of CNFs and evaluated using SEM, TGA/DTG and XRD to analyze the morphology, thermal behavior and crystallinity of bio nanocomposite films. SEM analysis revealed the uniform dispersion of CNFs in CHP matrix. Thermal stability of prepared bio nanocomposite films was improved with the loading of 5 wt% of cellulose nanofibers. ATR(FT-IR) spectra shows physical interaction between all the components of bio nanocomposite film. The bio nanocomposite films were also characterized for physical property like thickness, mechanical testing and barrier properties. The addition of CNFs significantly enhanced the mechanical property of bio nanocomposite films. Furthermore, water and oxygen transmission rate of bio nanocomposite film decreased with the increase in CNFs concentration. Overall the performed studies confirmed, the use of CNFs in polymer matrix makes it possible to produce a flexible, transparent, thermally stable bio nanocomposite film with enhanced mechanical and barrier properties for food packaging applications.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Intrinsic Quantum Dissipation in Superconducting Weak Links

We evaluate the frequency spectrum for an intrinsic quantum dissipative environment for the Josephson phase φ formed by subgap Andreev bound states in superconducting weak links. We also analyze the problem of macroscopic quantum tunneling (MQT) of φ in highly transparent weak links and identify several MQT regimes. Within the exponential accuracy, we derive the expression for the supercurrent quantum decay rate both at low temperatures and in the vicinity of the quantum-to-classical crossover.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Magnetism and Optical Property of Mn-Doped Monolayer CrSi{sub 2} by First-Principle Study

We investigate magnetism and optical properties of intrinsic and Mn-doped monolayer CrSi{sub 2} using the first-principle methods based on density functional theory. The results show that both monolayer CrSi{sub 2} sheets are metallic and ferromagnetic (FM) that hold promise in future 2D magnetic devices. In spite the slight reduction of the total magnetic moment of system after Mn doping in monolayer CrSi{sub 2}, the formation energies of ferromagnetic CrSi{sub 2} are also reduced. So, Mn doping in monolayer CrSi{sub 2} can have more promising applications in spintronics and magnetic storage. The optical properties of monolayer CrSi{sub 2}, including the absorption spectra, reflectivity, refractive index, loss function and dielectric function are also calculated. The intensity of reflectivity in far-infrared ranges is enhanced and real part n of refractive index decreases after Mn doping. The real part n of the refractive index is nearly constant (˜1) beyond 13 eV indicating that monolayer CrSi2 is vacuum like and fully transparent.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Development of Room-Temperature Ferromagnetism in Nanocomposite CdO Codoped with Al and Gd: Treatment in Hydrogen Atmosphere

Cadmium oxide codoped with Al and Gd ion powders was synthesised by thermal codecomposition of a mixture of complexes of cadmium acetate dihydrate, gadolinium acetate hydrate, and aluminum nitrate nonahydrate. The mass ratio of Al/Cd was fixed while the mass ratio of Gd/Cd varied systematically. The purpose of the present study is to synthesise and study the transparent conducting oxide (TCO) CdO powder having room-temperature ferromagnetic (RT-FM) properties. To realize that purpose, the synthesised Al/Gd-codoped CdO powder was annealed under hydrogen gas with certain conditions. The X-ray diffraction (XRD) method confirmed the formation of a single nanocrystalline structure; thus, both Al/Gd ions were incorporated into CdO lattice forming solid solutions. Magnetic measurements revealed that some of the doped CdO powders gained paramagnetic (PM) properties where the susceptibility increases with increasing dopant Gd content; the measured effective magnetic moment of dopant Gd{sup 3+} was around 8 μ{sub B}. Furthermore, the magnetic energy of the created RT-FM of the codoped CdO samples by hydrogenation was found to be dependent on the Gd% doping level. For hydrogenated CdO powder doped with 3% Gd, the coercivity (H{sub c}) was 195.9 Oe, the remanence (M{sub r}) was 0.77 memu/g, the saturation magnetisation (M{sub s}) was 5.05 memu/g, and the energy product (U{sub m}) was 150.6 merg/g. Thus, the possibility of production of TCO CdO with RT-FM, where magnetic characteristics can be tailored by doping and post treatment under H{sub 2} gas, was proven. Thus, a new potential candidate to be used as a dilute magnetic semiconductor (DMS) was successfully synthesised.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

The Additive Approximation for Heat Transfer and for Stability Calculations in a Multi-filamentary Superconductor - part A

This paper addresses the applicability of the “additive approximation” of total thermal conductivity in heat transfer and in superconductor stability calculations. If cases (a), (b) and (c) denote total (conductive plus radiative), or only conductive or only radiative heat flux, respectively, each flux q-dot calculated with Fourier’s conduction law using the corresponding thermal conductivity (λ{sub a}, λ{sub b}, λ{sub c}), the additive approximation would be confirmed if the heat flux difference Δ q-dot = q-dot {sub a}− q-dot {sub b}− q-dot {sub c}, at any position of an investigated object, and at any time, converges to zero. This is not trivial because of the strong, non-linear temperature dependence of the radiation component. Heat transfer calculations including radiative transfer are presented in this paper, first for simple, homogeneous, thin film test samples and later for a multi-filamentary BSCCO 2223 superconductor. The simulated heat sources either result from a sudden increase of conductor boundary temperature or from flux flow and Ohmic resistances in the superconductor under a disturbance (like transport current exceeding critcal current density). The conductors, though very thin, are non-transparent to mid-IR radiation. Validity of the additive approximation is critical for superconductor stability against quench. Based on the applied numerical scheme, a hypothesis is suggested concerning correlation of the results of the simulation (the “numerical space”) with the experimental situation (the “physical reality”): Non-convergence of the numerical scheme might tightly be correlated with occurrence of a quench in the simulated superconductor.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2019

Hydrogen-Induced Room-Temperature Ferromagnetism in Carbon-Incorporated CdO

Carbon-incorporated CdO (CdO–C) nanocrystallites were synthesised by sol–gel technique including sucrose (C{sub 12}H{sub 22}O{sub 11}) as a source of carbon ions. This investigation aimed to disclose the necessary synthesis conditions to create room-temperature ferromagnetic (RT-FM) properties in host CdO–C system. Therefore, structural, optical and magnetic properties of CdO–C samples were systematically investigated. The X-ray diffraction (XRD) method was used to study the structural properties, and the diffuse reflection spectroscopy (DRS) method was used to study the optical properties. It was established that post-annealing of synthesised samples in H{sub 2} atmosphere could create RT-FM. The experimental results were discussed in the framework of previous studies of other transparent conducting oxides (TCOs). The magnetic properties of CdO–C system were studied here for the first time. It was found that CdO–C nanopowder of tailored FM properties could be used as a candidate for TCO applications.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

C{sup ∗}-Quadratic Quantization

In the first part of the paper we introduce a new parametrization for the manifold underlying quadratic analogue of the usual Heisenberg group introduced in Accardi et al. (Infin Dimens Anal Quantum Probab Relat Top 13:551–587, 2010) which makes the composition law much more transparent. In the second part of the paper the new coordinates are used to construct an inductive system of ∗-algebras each of which is isomorphic to a finite tensor product of copies of the one-mode quadratic Weyl algebra. We prove that the inductive limit ∗-algebra is factorizable and has a natural localization given by a family of ∗-sub-algebras each of which is localized on a bounded Borel subset of ℝ. Moreover, we prove that the family of quadratic analogues of the Fock states, defined on the inductive family of ∗-algebras, is projective hence it defines a unique state on the limit ∗-algebra. Finally we complete this ∗-algebra under the (minimal regular) C{sup ∗}-norm thus obtaining a C{sup ∗}-algebra.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Engaging stakeholders to assess landscape sustainability

There is widespread consensus about the need for landscape sustainability but little agreement about how to define or measure it. Objectives: The aim of the paper is to present a systematic approach for measuring progress toward landscape sustainability goals. Methods: The approach was developed based on existing literature and our experiences in applying the approach to support more sustainable agricultural landscapes. Examples applying this approach are summarized for case studies in the United States (U.S.) and Mexico. Results: The approach has six steps: the scope and objectives of the assessment are determined based on the particular context; indicators that alert pending concerns are selected and prioritized based on utility and relevance; baselines and targets are established for each indicator, and scenarios for consideration are determined; the indicator values are obtained and evaluated; trends in and tradeoffs among indicator values are analyzed; and good practices are developed, applied, and assessed. Conclusions: Insights gained from applying this approach suggest that designing sustainable landscapes depends on stakeholder engagement, effective communication, transparency and trust, timely monitoring, and continual improvement. Iterative application of the assessment approach builds capacity and promotes continual improvements in management practices, thus enabling timely responses to changing conditions while still progressing toward a set of locally defined goals.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

The transmittance and sheet resistance of chemically and heat reduced graphene oxide film

The graphene oxide (GO) sheets were prepared from Hummer’s method. The reduced process is important to graphene related materials for widely functional use in many photoelectric fields. Chemically and heat reduced treatment are carried out in this research and the electrical and optical properties of reduced GO films are measured. The size of GO sheets was examined by transmission electron microscopy with a size of about 5–6 µm. The chemically converted graphene (CCG) film are made by spin coating method. We used different GO concentration and different spin coating times to investigate the properties of graphene transparent conductive films. As the decrease of the GO concentration of solution and the times of spin coating, the transmittance is higher. The electrical property of the mixing of GO and CCG is more stable than the GO sheets only, this is discussed in this research and it is cause by the stacking condition of sheets. The conductivity of reduced graphene oxide film come from GO is lower than that come from CCG, we suppose that is because that the overlapping is less (i.e. film-forming ability) in the former, the transmittance and sheet resistance are 56 T% and 50 kohm/sq.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Broadband LWIR and MWIR absorber by trapezoid multilayered grating and SiO{sub 2} hybrid structures

A broadband metamaterial absorber with high absorption simultaneously in mid-wave infrared (MWIR) and long-wave infrared (LWIR) was proposed. In the MWIR, the absorption higher than 0.8 is from 4 to 6.3 µm, while the absorption in the LWIR is from 8.7 and 9.6 µm. The absorber is insensitive to the incident angle. The broadband absorption in the MWIR is due to the slow-light effect of the trapezoid multilayered grating structure. And the broadband absorption in the LWIR is due to the phonon polariton resonant of trapezoid SiO{sub 2} layer. In the broadband high absorption region, the atmosphere is transparent, which may greatly promote the practical application of the absorber in double-color IR imaging, detecting, infrared stealth and thermal emitting.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

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