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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Feasibility study: Monodisperse polymer particles containing laser-excitable dyes

The objective was to determine the feasibility of the preparation of monodisperse spherical poly(methyl methacrylate) and polystyrene particles that contain laser-excitable dyes in the size range 0.1 microns to 1 cm. Poly(methyl methacrylate) and polystyrene were chosen because of their excellent optical properties. The sphericity was required for uniformity of spectral output of re-irradiated light from the dye-containing particles. The monodispersity was required to give each particle the same optical properties when exposed to laser light.

Vanderhoff, John W.↗
NASA NTRS1996

Verifying Removal Of Red Penetrant Dye From Inspected Welds

Clean surface assured for more sensitive inspection with fluorescent penetrant dye. Simple procedure devised to ensure visible (red) penetrant dye used to identify flaws in welded surface completely removed from surface. Consists in applying reversible penetrant developer to surface to be inspected.

Torkelson, Jan R.↗
NASA NTRS1996

Visualizing Vector Fields Using Line Integral Convolution and Dye Advection

We present local and global techniques to visualize three-dimensional vector field data. Using the Line Integral Convolution (LIC) method to image the global vector field, our new algorithm allows the user to introduce colored 'dye' into the vector field to highlight local flow features. A fast algorithm is proposed that quickly recomputes the dyed LIC images. In addition, we introduce volume rendering methods that can map the LIC texture on any contour surface and/or translucent region defined by additional scalar quantities, and can follow the advection of colored dye throughout the volume.

Shen, Han-Wei↗
NASA NTRS2001

Substituent and Solvent Effects on Excited State Charge Transfer Behavior of Highly Fluorescent Dyes Containing Thiophenylimidazole-Based Aldehydes

The excited state charge transfer for a series of highly fluorescent dyes containing thiophenylimidazole moiety was investigated. These systems follow the Twisted Intramolecular Charge Transfer (TICT) model. Dual fluorescence was observed for each substituted dye. X-ray structures analysis reveals a twisted ground state geometry for the donor substituted aryl on the 4 and 5 position at the imidazole ring. The excited state charge transfer was modeled by a linear solvation energy relationship using Taft's pi and Dimroth's E(sub T)(30) as solvent parameters. There is linear relation between the energy of the fluorescence transition and solvent polarity. The degree of stabilization of the excited state charge transfer was found to be consistent with the intramolecular molecular charge transfer. Excited dipole moment was studied by utilizing the solvatochromic shift method.

Santos, Javier↗
NASA NTRS2004

Photophysics of Laser Dye-Doped Polymer Membranes for Laser-Induced Fluorescence Photogrammetry

Laser-induced fluorescence target generation in dye-doped polymer films has recently been introduced as a promising alternative to more traditional photogrammetric targeting techniques for surface profiling of highly transparent or reflective membrane structures. We investigate the photophysics of these dye-doped polymers to help determine their long-term durability and suitability for laser-induced fluorescence photogrammetric targeting. These investigations included experimental analysis of the fluorescence emission pattern, spectral content, temporal lifetime, linearity, and half-life. Results are presented that reveal an emission pattern wider than normal Lambertian diffuse surface scatter, a fluorescence time constant of 6.6 ns, a pump saturation level of approximately 20 micro J/mm(exp 2), and a useful lifetime of more than 300,000 measurements. Furthermore, two demonstrations of photogrammetric measurements by laser-induced fluorescence targeting are presented, showing agreement between photogrammetric and physically measured dimensions within the measurement scatter of 100 micron.

Dorrington, Adrian A.↗
NASA NTRS2003

Corrosion Inhibitors as Penetrant Dyes for Radiography

Liquid/vapor-phase corrosion inhibitors (LVCIs) have been found to be additionally useful as penetrant dyes for neutron radiography (and perhaps also x-radiography). Enhancement of radiographic contrasts by use of LVCIs can reveal cracks, corrosion, and other defects that may be undetectable by ultrasonic inspection, that are hidden from direct optical inspection, and/or that are difficult or impossible to detect in radiographs made without dyes.

Novak, Howard L.↗
DOE OSTI2010

Microwave hydrothermal synthesis and photocatalytic activity of AgIn{sub 5}S{sub 8} for the degradation of dye

AgIn{sub 5}S{sub 8} powders were successfully synthesized by a microwave hydrothermal method for the first time. This method is a mild and highly efficient route involves no templates, catalysts, or surfactants. Therefore, it is very promising for the low-cost and large-scale industrial production. The samples were characterized by X-ray diffraction, UV-vis spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The photocatalytic activity of AgIn{sub 5}S{sub 8} nanoparticles was investigated through the degradation of methyl orange under visible light irradiation. Compared with TiO{sub 2-x}N{sub x}, AgIn{sub 5}S{sub 8} has exhibited a superior activity under the same condition. A liquid chromatogram-mass spectrometer was used to separate and identify the dye and degradation products generated during the reaction. According to the experiment results, a possible mechanism for the degradation of organic pollutant over AgIn{sub 5}S{sub 8} was proposed. - Graphical abstract: Compared with TiO{sub 2-x}N{sub x}, AgIn{sub 5}S{sub 8} has exhibited a superior activity under the same condition.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2011

Pyridinium molten salts as co-adsorbents in dye-sensitized solar cells

The influence of using pyridinium molten salts as co-adsorbents to modify the monolayer of a TiO{sub 2} semiconductor on the performance of a dye-sensitized solar cell is studied. The current-voltage characteristics are measured under AM 1.5 (100 mW cm{sup -2}). The pyridinium molten salts significantly enhance the open-circuit photovoltage (V{sub oc}), the short circuit photocurrent density (J{sub sc}) as well as the solar energy conversion efficiency ({eta}). 1-Ethyl-3-carboxypyridinium iodide ([ECP][I]) is applied successfully to prepare an insulating molecular layer with N719, and achieve high energy conversion efficiency as high as 4.49% at 100 mW cm{sup -2} and AM 1.5. The resulting efficiency is 20% higher than that of a non-additive device. This enhancement of conversion efficiency is attributed to the negative shift of the conduction band (CB) edge and the abundant concentration of I{sup -} on the surface of the electrode when using [ECP][I] as the co-adsorbent. (author)

14 SOLAR ENERGY↗
DOE OSTI2018

Acid–Base Properties of Azo Dyes in Solution Studied Using Spectrophotometry and Colorimetry

Colorimetry and spectrophotometry with chemometric data processing were used to study the acid–base properties of azo dyes in aqueous solution. The capabilities of both methods were compared. Ionization constants of all the functional groups of the azo compounds studied could be determined relative to the change in the specific color difference depending on the acidity of the medium. The colorimetric functions of ion-molecular forms of azo compounds used as an analytical signal allow us to obtain complete information on the acid–base equilibrium in a wide acidity range.

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

A Colorimetric and Fluorescent Chemosensor of Fe{sup 3+} Based on an Asymmetrical Squarylium Dye

A novel asymmetrical squarylium-dye-based dual signaling probe was synthesized and found to exhibit colorimetric and fluorescent properties on selective binding towards Fe{sup 3+} in ethanol/water (4:1, v/v) solution. The binding constant was determined to be 7.69 × 10{sup 2} M{sup –1}, and the detection limit of SQ was 9.158 × 10{sup –6} M. Most importantly, the 1:2 stoichiometry of the host-guest complexation was confirmed by Job’s method. Moreover, the high sensing ability of the receptor towards Fe{sup 3+} was also investigated by the electrochemical technique.

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

Dual Function of Cellulose Triacetate–Graft–Polymethacrylic Acid Films for Dyes Removal and for High-Dose Radiation Dosimetry

Graft copolymerization of methacrylic acid (MAc) onto cellulose triacetate (CTA) films was conducted by gamma rays. The grafting conditions were optimized. The structure of grafted CTA films was characterized by Fourier transform infra red–attenuated total reflection, scanning electron microscopy, thermal gravimetric analysis, CHNS/O microanalyzer and, surface area and porosity analyzer. The grafted CTA films were exploited in adsorption of ethyl violet (EV) and phenol red (PR) dyes. The adsorption capacity of the grafted CTA films was investigated at various variables. The adsorption isotherms and kinetic study were examined. Further, the dyed grafted CTA films were used in measurements of high dose radiation. The results indicate that the useful dose range extents up to 440 and 300 kGy for EV and PR, respectively. The effects of relative humidity during irradiation, shelf-life, pre- and post-irradiation storage in dark and indirect daylight conditions on dosimeters performance were investigated.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Synthesis, Luminescence and Thermal Properties of PVA–ZnO–Al{sub 2}O{sub 3} Composite Films: Towards Fabrication of Sunlight-Induced Catalyst for Organic Dye Removal

Poly(vinyl alcohol) (PVA)–ZnO–Al{sub 2}O{sub 3} composite films have been prepared by the addition of different compositions of ZnO and Al{sub 2}O{sub 3} through solvent casting method. Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–Vis) and photoluminescence spectroscopy (PL) spectra revealed the successful incorporation of ZnO and Al{sub 2}O{sub 3} onto PVA and interactions among ZnO, Al{sub 2}O{sub 3} and PVA molecules. PL data indeed showed the enhanced luminescence property of composite films compared with the PVA. Thermogravimetric analysis (TGA) data showed that thermal stability of PVA–ZnO–Al{sub 2}O{sub 3} composite films could be greatly improved by the incorporation of ZnO and Al{sub 2}O{sub 3} into the system. The glass transition temperature (T{sub g}) were increased for the composite samples using ZnO and Al{sub 2}O{sub 3}. Differential scanning calorimetry (DSC) measurements revealed that the melting temperature (T{sub m}) of PVA–ZnO–Al{sub 2}O{sub 3 }composite films are significantly higher (~ 12 to 25 °C) than PVA. The photocatalytic measurements exhibited better photocatalytic degradation ability of PVA–ZnO–Al{sub 2}O{sub 3} composites over PVA. Such photocatalytic capacity makes the PVA–ZnO–Al{sub 2}O{sub 3} composite films promising candidates for the removal of organic dyes for water purification.

36 MATERIALS SCIENCE↗
DOE OSTI2019

N-Silylated Benzothiazolium Dye as a Coupling Agent for Polylactic Acid/Date Palm Fiber Bio-composites

This work proposes a benzothiazole derivative bearing a silane moiety as a new coupling agent for polylactic acid (PLA) reinforced by date palm fibers (DPFs). The bio-composites are prepared by solution blending followed by melt compounding. From the samples produced, a complete characterization is performed including morphological, mechanical and thermal properties as a function of fiber content. The results show that the proposed fiber treatment is an easy and effective method to improve the interfacial properties and fiber dispersion leading to better material performance. For example, the addition of only 1 wt% of the dye–IPTMS to the bleached DPF not only improved the thermal stability of the biocomposites, but also led to a significant increase of the Young’s modulus at 7 wt% and higher torsion modulus up to 5 wt% (optimum value).

36 MATERIALS SCIENCE↗
DOE OSTI2019

A periodic metallo-supramolecular polymer from a flexible building block: self-assembly and photocatalysis for organic dye degradation

A water-soluble metallo-supramolecular polymer MSP-f-6Np , which possesses a regular pore aperture of 1.4 nm, has been assembled from a structurally flexible naphthalene-appended [Ru(bipy) 3 ] 2+ complex and cucurbit[8]uril. As the first periodic metallo-supramolecular polymer formed by a flexible building block, MSP-f-6Np exhibits a hydrodynamic diameter of 122 and 164 nm at 0.1 and 2.0 mM of the monomer concentrations. Synchrotron small angle X-ray scattering experiments confirm that MSP-f-6Np possesses porosity periodicity in both the solution and solid states. Compared with a control, the new highly ordered porous system displays enhanced photocatalytic activity for the degradation of organic dyes.

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

A de novo sacrificial-MOF strategy to construct enhanced-flux nanofiltration membranes for efficient dye removal

Nanofiltration membanes play a critical role in alleviating global water scarcity, affecting more than 4 billion people. Here, a new metal organic framework (MOF) sacrificicial strategy is designed to synthesize flux-enhancing nanofiltration membrane for efficient dye removal. With the aid of polyphenol chemistry, ZIF-67 MOF was first coated onto a porous support and in situ transformed into a selective layer by virtue of pyrrole polymerization. Trigerred by ammonium persulfate, polypyrrole selective layer functioalized nanofiltration membrane was fabricated when accompanying pore regulation by MOF self-sacrifice. The membrane demonstrated a flux enhancement of 745% than pristine polypyrrole (PPy) one with maintained rejection. Furthermore, the synergistic interactions among polypyrrole, polyphenol, and porous support endowed membrane with excellent stability during long term test. The designed MOF sacrificed route may open a new avenue for fabricating advanced energetic-efficient membranes with the reconstructed architecture towards diverse separation applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2011

Optimization of processing parameters on the controlled growth of ZnO nanorod arrays for the performance improvement of solid-state dye-sensitized solar cells

High-transparency and high quality ZnO nanorod arrays were grown on the ITO substrates by a two-step chemical bath deposition (CBD) method. The effects of processing parameters including reaction temperature (25-95 {sup o}C) and solution concentration (0.01-0.1 M) on the crystal growth, alignment, optical and electrical properties were systematically investigated. It has been found that these process parameters are critical for the growth, orientation and aspect ratio of the nanorod arrays, showing different structural and optical properties. Experimental results reveal that the hexagonal ZnO nanorod arrays prepared under reaction temperature of 95 {sup o}C and solution concentration of 0.03 M possess highest aspect ratio of {approx}21, and show the well-aligned orientation and optimum optical properties. Moreover the ZnO nanorod arrays based heterojunction electrodes and the solid-state dye-sensitized solar cells (SS-DSSCs) were fabricated with an improved optoelectrical performance. -- Graphical abstract: The ZnO nanorod arrays demonstrate well-alignment, high aspect ratio (L/D{approx}21) and excellent optical transmittance by low-temperature chemical bath deposition (CBD). Display Omitted Research highlights: > Investigate the processing parameters of CBD on the growth of ZnO nanorod arrays. > Optimization of CBD process parameters: 0.03 M solution concentration and reaction temperature of 95 {sup o}C. > The prepared ZnO samples possess well-alignment and high aspect ratio (L/D{approx}21). > An n-ZnO/p-NiO heterojunction: great rectifying behavior and low leakage current. > SS-DSSC has J{sub SC} of 0.31 mA/cm{sup 2} and V{sub OC} of 590 mV, and an improved {eta} of 0.059%.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Synthesis of ZnO-TiO{sub 2} core-shell long nanowire arrays and their application on dye-sensitized solar cells

Long ZnO nanowire arrays (NAs) grown on fluorine-doped tin oxide (FTO) glasses have been synthesized via a facile hydrothermal method without refreshing the reaction solution and applied as the precursor. By adjusting growth conditions, ZnO NAs with tunable lengths can be achieved. A nanocomposite made of ZnO nanowire core and TiO{sub 2} shell was further realized by a novel 'fast-dip-coating' method conducted in a Ti(OC{sub 4}H{sub 9}){sub 4}-dissolved ethanol solution. The formed ZnO-TiO{sub 2} core-shell NAs on FTO substrates were applied as electrodes for dye sensitized solar cells (DSSCs). It is found that both the TiO{sub 2} coating and NAs length play important roles in the enhancement of photoelectric conversion efficiency (PCE) of DSSCs. When the length of ZnO-TiO{sub 2} NAs reaches up to 14 {mu}m, the electrode can exhibit a maximum PCE as high as 3.80%, which is 2.6 times higher than that of pure ZnO NAs. - Graphical abstract: ZnO nanowire arrays in the length of 14 {mu}m have been successfully synthesized on the FTO substrate and coated with a thin shell of TiO{sub 2}; the ZnO-TiO{sub 2} electrodes applied in DSSCs exhibit great photoelectric conversion efficiency as high as 3.80%. Highlights: Black-Right-Pointing-Pointer Long ZnO nanowire arrays have been synthesized by using hydrothermal method. Black-Right-Pointing-Pointer A TiO{sub 2} shell outside of ZnO nanowire is introduced by a fast dip-coating method. Black-Right-Pointing-Pointer ZnO and ZnO-TiO{sub 2} core-shell nanowires are applied as the electrodes for DSSCs. Black-Right-Pointing-Pointer The maximum conversion efficiency of ZnO-TiO{sub 2} electrode reaches to 3.80%.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗