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Sample records for model dye systems

  1. Dye system for dye laser applications

    DOEpatents

    Hammond, Peter R.

    1991-01-01

    A dye of the DCM family, [2-methyl-6-[2-(1,2,3,4-tetrahydro-1-methyl-6-quinolinyl)ethenyl]-4H-pyran -4-ylidene]-propanedinitrile, dissolved in 2-phenoxyethanol, is non-mutagenic, stable and efficient, particularly in a pumped continuous wave laser system.

  2. Examining protein-lipid interactions in model systems with a new squarylium fluorescent dye.

    PubMed

    Ioffe, Valeriya M; Gorbenko, Galyna P; Tatarets, Anatoliy L; Patsenker, Leonid D; Terpechnig, Ewald A

    2006-07-01

    The applicability of newly synthesized squarylium dye Sq to probing the changes in physical characteristics of lipid bilayer on the formation of protein-lipid complexes has been evaluated. Lipid vesicles composed of zwitterionic phospholipid phosphatidylcholine (PC) and its mixtures with positively charged detergent cetyltrimethylammonium bromide (CTAB), anionic phospholipid cardiolipin (CL), and cholesterol (Chol) were employed as lipid component of model membrane systems while protein constituent was represented by lysozyme (Lz). Fluorescence intensity of Sq was found to decrease on Lz association with lipid bilayer. This effect was observed in all kinds of model systems suggesting that Sq is sensitive to modification of lipid bilayer physical properties on hydrophobic protein-lipid interactions. It was found that Sq spectral response to variations in Chol content depends on relative contributions of electrostatic and hydrophobic components of Lz-membrane binding.

  3. Model system for multifunctional delivery nanoplatforms based on DNA-Polymer complexes containing silver nanoparticles and fluorescent dye.

    PubMed

    Kasyanenko, Nina; Bakulev, Vladimir; Perevyazko, Igor; Nekrasova, Tatiana; Nazarova, Olga; Slita, Alexandr; Zolotova, Yulia; Panarin, Euginii

    2016-10-20

    Creation of multifunctional nanoplatforms is one of the new approaches to complex treatment and diagnosis with the monitoring of the curative process. Inclusion of various components into the drug delivery system may reduce toxicity and enhance or modify the therapeutic effects of medicines. In particular, some properties of metal nanoparticles and nanoclusters provide the ability to create new systems for treatment and diagnosis of diseases, biocatalysis and imaging of objects. For example, the ability of metal nanoparticles to enhance the quantum yield of luminescence can be used in bioimaging and therapy. The aim of the research was to construct and examine a multicomponent system based on DNA-polycation compact structure with the inclusion of silver nanoparticles and luminescent dye as a model system for delivery of genes and drugs with the possibility of modification and enhancement of their action.

  4. Equilibrium, kinetics and mechanism modeling and simulation of basic and acid dyes sorption onto jute fiber carbon: Eosin yellow, malachite green and crystal violet single component systems.

    PubMed

    Porkodi, K; Vasanth Kumar, K

    2007-05-08

    Batch experiments were carried out for the sorption of eosin yellow, malachite green and crystal violet onto jute fiber carbon (JFC). The operating variables studied are the initial dye concentration, initial solution pH, adsorbent dosage and contact time. Experimental equilibrium data were fitted to Freundlich, Langmuir and Redlich-Peterson isotherm by non-linear regression method. Langmuir isotherm was found to be the optimum isotherm for eosin yellow/JFC system and Freundlich isotherm was found to be the optimum isotherm for malachite green/JFC and crystal violet/JFC system at equilibrium conditions. The sorption capacities of eosin yellow, malachite green and crystal violet onto JFC according to Langmuir isotherm were found to 31.49 mg/g, 136.58 mg/g, 27.99 mg/g, respectively. A single stage batch adsorber was designed for the adsorption of eosin yellow, malachite green and crystal violet onto JFC based on the optimum isotherm. A pseudo second order kinetic model well represented the kinetic uptake of dyes studied onto JFC. The pseudo second order kinetic model successfully simulated the kinetics of dye uptake process. The dye sorption process involves both surface and pore diffusion with predominance of surface diffusion at earlier stages. A Boyd plot confirms the external mass transfer as the rate limiting step in the dye sorption process. The influence of initial dye concentration on the dye sorption process was represented in the form of dimensionless mass transfer numbers (Sh/Sc(0.33)) and was found to be agreeing with the expression:

  5. Picosecond spectroscopic studies of energy transfer in phycobiliproteins and model dye systems

    SciTech Connect

    Switalski, S.C.

    1987-02-01

    Energy transfer was investigated in the ..cap alpha beta.. monomer and separated ..cap alpha.. and ..beta.. subunits of C-phycocyanin from Anabaena variabilis and Anacystis nidulans, using steady-state and picosecond spectroscopy. Fluorescence excitation polarization spectra were consistent with a sensitizing (s) - fluorescing (f) model using a Forster energy transfer mechanism. The rise in polarization across the absorption band towards longer wavelength for the ..beta.. subunit and the ..cap alpha beta.. monomer was attributed to energy transfer among the three chromophores in the ..cap alpha beta.. monomer and between the 2 chromophores in the ..beta.. subunit. The constant polarization of the ..cap alpha.. subunit, with one chromophore, is consistent with a lack of any possibility of energy transfer. Fluorescence emission maxima were at 640 nm for the ..cap alpha beta.. monomer and the separated subunits of Anabaena variabilis, and 645 nm for the ..beta.. subunit, 640 nm for the ..cap alpha.. subunit, and 644 nm for ..cap alpha beta.. monomer of Anacystis nidulans. We have shown that the labels s and f are not consistent with all the steady-state spectroscopic results. 171 refs., 32 figs., 15 tabs.

  6. Genetic algorithm-artificial neural network and adaptive neuro-fuzzy inference system modeling of antibacterial activity of annatto dye on Salmonella enteritidis.

    PubMed

    Yolmeh, Mahmoud; Habibi Najafi, Mohammad B; Salehi, Fakhreddin

    2014-01-01

    Annatto is commonly used as a coloring agent in the food industry and has antimicrobial and antioxidant properties. In this study, genetic algorithm-artificial neural network (GA-ANN) and adaptive neuro-fuzzy inference system (ANFIS) models were used to predict the effect of annatto dye on Salmonella enteritidis in mayonnaise. The GA-ANN and ANFIS were fed with 3 inputs of annatto dye concentration (0, 0.1, 0.2 and 0.4%), storage temperature (4 and 25°C) and storage time (1-20 days) for prediction of S. enteritidis population. Both models were trained with experimental data. The results showed that the annatto dye was able to reduce of S. enteritidis and its effect was stronger at 25°C than 4°C. The developed GA-ANN, which included 8 hidden neurons, could predict S. enteritidis population with correlation coefficient of 0.999. The overall agreement between ANFIS predictions and experimental data was also very good (r=0.998). Sensitivity analysis results showed that storage temperature was the most sensitive factor for prediction of S. enteritidis population.

  7. Adsorption kinetics and isotherm of anionic dyes onto organo-bentonite from single and multisolute systems.

    PubMed

    Shen, Dazhong; Fan, Jianxin; Zhou, Weizhi; Gao, Baoyu; Yue, Qinyan; Kang, Qi

    2009-12-15

    The performances of polydiallydimethylammonium modified bentonite (PDADMA-bentonite) as an adsorbent to remove anionic dyes, namely Acid Scarlet GR (AS-GR), Acid Turquoise Blue 2G (ATB-2G) and Indigo Carmine (IC), were investigated in single, binary and ternary dye systems. In adsorption from single dye solutions with initial concentration of 100 micromol/L, the dosage of PDADMA-bentonite needed to remove 95% dye was 0.42, 0.68 and 0.75 g/L for AS-GR, ATB-2G and IC, respectively. The adsorption isotherms of the three dyes obeyed the Langmuir isotherm model with the equilibrium constants of 0.372, 0.629 and 4.31 L/micromol, the saturation adsorption amount of 176.3, 149.2 and 228.7 micromol/g for ATB-2G, IC and AS-GR, respectively. In adsorption from mixed dye solutions, the isotherm of each individual dye followed an expanded Langmuir isotherm model and the relationship between the total amount of dyes adsorbed and the total equilibrium dye concentration was interpreted well by Langmuir isotherm model. In the region of insufficient dosage of PDADMA-bentonite, the dye with a larger affinity was preferentially removed by adsorption. Desorption was observed in the kinetic curve of the dye with lower affinity on PDADMA-bentonite surface by the competitive adsorption. The kinetics in single dye solution and the total adsorption of dyes in binary and ternary dye systems nicely followed pseudo-second-order kinetic model.

  8. Observations and modeling of a tidal inlet dye tracer plume

    NASA Astrophysics Data System (ADS)

    Feddersen, Falk; Olabarrieta, Maitane; Guza, R. T.; Winters, D.; Raubenheimer, Britt; Elgar, Steve

    2016-10-01

    A 9 km long tracer plume was created by continuously releasing Rhodamine WT dye for 2.2 h during ebb tide within the southern edge of the main tidal channel at New River Inlet, NC on 7 May 2012, with highly obliquely incident waves and alongshore winds. Over 6 h from release, COAWST (coupled ROMS and SWAN, including wave, wind, and tidal forcing) modeled dye compares well with (aerial hyperspectral and in situ) observed dye concentration. Dye first was transported rapidly seaward along the main channel and partially advected across the ebb-tidal shoal until reaching the offshore edge of the shoal. Dye did not eject offshore in an ebb-tidal jet because the obliquely incident breaking waves retarded the inlet-mouth ebb-tidal flow and forced currents along the ebb shoal. The dye plume largely was confined to <4 m depth. Dye was then transported downcoast in the narrow (few 100 m wide) surfzone of the beach bordering the inlet at 0.3 m s-1 driven by wave breaking. Over 6 h, the dye plume is not significantly affected by buoyancy. Observed dye mass balances close indicating all released dye is accounted for. Modeled and observed dye behaviors are qualitatively similar. The model simulates well the evolution of the dye center of mass, lateral spreading, surface area, and maximum concentration, as well as regional ("inlet" and "ocean") dye mass balances. This indicates that the model represents well the dynamics of the ebb-tidal dye plume. Details of the dye transport pathways across the ebb shoal are modeled poorly perhaps owing to low-resolution and smoothed model bathymetry. Wave forcing effects have a large impact on the dye transport.

  9. Photocatalytic property of a keggin-type polyoxometalates-containing bilayer system for degradation organic dye model.

    PubMed

    Li, Taohai; Gao, Shuiying; Li, Feng; Cao, Rong

    2009-10-15

    The photocatalytic activity composite films incorporating the Keggin-type polyoxometalates (POM) K6CoW12O40.-16H2O and K3PW12O40.-nH2O (MW12 (M=P, Co)) and [Cu(II)(1,8-dimethyl-1, 3, 6, 8, 10, 13-hexaazacycloteradecane)](2+)(L) have been prepared by the layer-by-layer (LbL) self-assembly method. The experimental results show that the deposition process is linear and highly reproducible from layer to layer. Atomic force microscopy (AFM) images of the L/MW12 composite films indicate that the film surface is relatively uniform and smooth. In addition, the films show high photocatalytic activity to the degradation of organic dye model (methyl orange (MO)), attributed to the formation of an O-->W charge-transfer excited state at W-O-W bridge bond, resulting in generating highly reactive holes and electrons; The photocatalytic efficiency of the films have little change after several times of photocatalytic cycle, indicating that the composite films are stable, reused and recovered.

  10. Modeling materials and processes in dye-sensitized solar cells: understanding the mechanism, improving the efficiency.

    PubMed

    Pastore, Mariachiara; De Angelis, Filippo

    2014-01-01

    We present a review of recent first-principles computational modeling studies on dye-sensitized solar cells (DSCs), focusing on the materials and processes modeling aspects which are key to the functioning of this promising class of photovoltaic devices. Crucial to the DSCs functioning is the photoinduced charge separation occurring at the heterointerface(s) between a dye-sensitized nanocrystalline, mesoporous metal oxide electrode and a redox shuttle. Theoretical and computational modeling of isolated cell components (e.g., dye, semiconductor nanoparticles, redox shuttle, etc…) as well as of combined dye/semiconductor/redox shuttle systems can successfully assist the experimental research by providing basic design rules of new sensitizers and a deeper comprehension of the fundamental chemical and physical processes governing the cell functioning and its performances. A computational approach to DSCs modeling can essentially be cast into a stepwise problem, whereby one first needs to simulate accurately the individual DSCs components to move to relevant pair (or higher order) interactions characterizing the device functioning. This information can contribute to enhancing further the target DSCs characteristics, such as temporal stability and optimization of device components. After presenting selected results for isolated dyes, including the computational design of new dyes, and model semiconductors, including realistic nanostructure models, we focus in the remainder of this review on the interaction between dye-sensitizers and semiconductor oxides, covering organic as well as metallorganic dyes.

  11. A model for recombination in Type II dye-sensitized solar cells: Catechol-thiophene dyes

    NASA Astrophysics Data System (ADS)

    Manzhos, Sergei; Segawa, Hiroshi; Yamashita, Koichi

    2011-03-01

    Recombination in dye-sensitized solar cells with direct injection is cast as internal conversion in the dye-Ti(OH) 2 complex. For catechol-thiophene dyes with 1, 2, or 3 thiophene units, the complex reproduces the previously observed dye-to-semiconductor bands. We compare the decomposition of the internal conversion rate by vibrational mode and predict a trend in recombination with the extension of conjugation, which offers an explanation for the trend in DSSC efficiency. We employ a simple model for the vibrational factors and show that they are only important in the presence of vibrational modes with ℏω⩽kT and strong electronic factors, as is the case here.

  12. Evaluation of respiratory system in textile-dyeing workers

    PubMed Central

    Salmani Nodoushan, Mojahede; Mehrparvar, Amir Houshang; Loukzadeh, Ziba; Rahimian, Masoud; Ghove Nodoushan, Mohamad ali; Jafari Nodoushan, Reza

    2014-01-01

    Background: Despite the presence of many textile and dyeing plants in Iran, we couldn’t find similar studies in this country. Forthermore, considering progress in the dyeing process and engineering controls, assessment of respiratory system is important for these workers. The present study was performed to evaluate the respiratory system in dyeing workers. Methods: In a cross-sectional study, 101 dyeing workers (all dyeing workers in yazd) and 90 workers without respiratory exposures (control group), were evaluated. A questionnaire was filled for each participant included Venables questionnaire and some other questions about age, work experience, personal or familial history of asthma or atopy, acute and chronic respiratory symptoms; Then spirometry was performed before and after the shift work Results: The frequency of acute and chronic respiratory symptoms was significantly higher among dyeing workers than controls. According to the Venables questionnaire, 11.9% of the dyeing workers suffered from asthma. Means of FVC and FEV1 of pre-shift spirometry were lower than control (p< 0.001). Across-shift spirometry showed significant reduction of FVC (p< 0.001), FEV1 (p< 0.001), FEF25-75% (p= 0.05) and FEF25% (p= 0.007) in dyeing workers compared to the control group. Conclusion: Evaluation of dyeing workers’ respiratory system in this study showed that despite development in dyeing processes and engineering controls, workers in this job show more prevalent acute and chronic symptoms, and across-shift changes in spirometric parameters were significantly higher in this work group than the control group. Therefore it is necessary to pay attention to the control of respiratory exposures in this job. PMID:25664289

  13. Optimization of Biosorptive Removal of Dye from Aqueous System by Cone Shell of Calabrian Pine

    PubMed Central

    Deniz, Fatih

    2014-01-01

    The biosorption performance of raw cone shell of Calabrian pine for C.I. Basic Red 46 as a model azo dye from aqueous system was optimized using Taguchi experimental design methodology. L9 (33) orthogonal array was used to optimize the dye biosorption by the pine cone shell. The selected factors and their levels were biosorbent particle size, dye concentration, and contact time. The predicted dye biosorption capacity for the pine cone shell from Taguchi design was obtained as 71.770 mg g−1 under optimized biosorption conditions. This experimental design provided reasonable predictive performance of dye biosorption by the biosorbent (R 2: 0.9961). Langmuir model fitted better to the biosorption equilibrium data than Freundlich model. This displayed the monolayer coverage of dye molecules on the biosorbent surface. Dubinin-Radushkevich model and the standard Gibbs free energy change proposed physical biosorption for predominant mechanism. The logistic function presented the best fit to the data of biosorption kinetics. The kinetic parameters reflecting biosorption performance were also evaluated. The optimization study revealed that the pine cone shell can be an effective and economically feasible biosorbent for the removal of dye. PMID:25405213

  14. Optimization of biosorptive removal of dye from aqueous system by cone shell of Calabrian pine.

    PubMed

    Deniz, Fatih

    2014-01-01

    The biosorption performance of raw cone shell of Calabrian pine for C.I. Basic Red 46 as a model azo dye from aqueous system was optimized using Taguchi experimental design methodology. L9 (3(3)) orthogonal array was used to optimize the dye biosorption by the pine cone shell. The selected factors and their levels were biosorbent particle size, dye concentration, and contact time. The predicted dye biosorption capacity for the pine cone shell from Taguchi design was obtained as 71.770 mg g(-1) under optimized biosorption conditions. This experimental design provided reasonable predictive performance of dye biosorption by the biosorbent (R (2): 0.9961). Langmuir model fitted better to the biosorption equilibrium data than Freundlich model. This displayed the monolayer coverage of dye molecules on the biosorbent surface. Dubinin-Radushkevich model and the standard Gibbs free energy change proposed physical biosorption for predominant mechanism. The logistic function presented the best fit to the data of biosorption kinetics. The kinetic parameters reflecting biosorption performance were also evaluated. The optimization study revealed that the pine cone shell can be an effective and economically feasible biosorbent for the removal of dye.

  15. Modelling of microcracks image treated with fluorescent dye

    NASA Astrophysics Data System (ADS)

    Glebov, Victor; Lashmanov, Oleg U.

    2015-06-01

    The main reasons of catastrophes and accidents are high level of wear of equipment and violation of the production technology. The methods of nondestructive testing are designed to find out defects timely and to prevent break down of aggregates. These methods allow determining compliance of object parameters with technical requirements without destroying it. This work will discuss dye penetrant inspection or liquid penetrant inspection (DPI or LPI) methods and computer model of microcracks image treated with fluorescent dye. Usually cracks on image look like broken extended lines with small width (about 1 to 10 pixels) and ragged edges. The used method of inspection allows to detect microcracks with depth about 10 or more micrometers. During the work the mathematical model of image of randomly located microcracks treated with fluorescent dye was created in MATLAB environment. Background noises and distortions introduced by the optical systems are considered in the model. The factors that have influence on the image are listed below: 1. Background noise. Background noise is caused by the bright light from external sources and it reduces contrast on the objects edges. 2. Noises on the image sensor. Digital noise manifests itself in the form of randomly located points that are differing in their brightness and color. 3. Distortions caused by aberrations of optical system. After passing through the real optical system the homocentricity of the bundle of rays is violated or homocentricity remains but rays intersect at the point that doesn't coincide with the point of the ideal image. The stronger the influence of the above-listed factors, the worse the image quality and therefore the analysis of the image for control of the item finds difficulty. The mathematical model is created using the following algorithm: at the beginning the number of cracks that will be modeled is entered from keyboard. Then the point with random position is choosing on the matrix whose size is

  16. Kinetic modeling of the adsorption of basic dyes by kudzu.

    PubMed

    Allen, Stephen J; Gan, Quan; Matthews, Ronan; Johnson, Pauline A

    2005-06-01

    The use of kudzu, a rapidly growing, high-climbing perennial leguminous vine, for the adsorption of basic dyes from aqueous solution has been investigated at various initial dye concentrations, masses of kudzu, and agitation rates. The extent and rate of adsorption of the three basic dyes (Basic Red 22, Basic Yellow 21, and Basic Blue 3) were analyzed using a pseudo-first-order and a pseudo-second-order kinetic model. While both rate mechanisms provided an acceptable degree of correlation with the experimental sorption rate data, the pseudo-second-order model gave a much higher degree of correlation, suggesting that this model could be used in design and simulation applications.

  17. Modeling opto-electronic properties of a dye molecule in proximity of a semiconductor nanoparticle

    NASA Astrophysics Data System (ADS)

    Delgado, Alain; Corni, Stefano; Goldoni, Guido

    2013-07-01

    A general methodology is presented to model the opto-electronic properties of a dye molecule in the presence of a semiconductor nanoparticle (NP), a model system for the architecture of dye-sensitized solar cells. The method is applied to the L0 organic dye solvated with acetonitrile in the neighborhood of a TiO2 NP. The total reaction potential due to the polarization of the solvent and the metal oxide is calculated by extending the polarizable continuum model integral equation formalism. The ground state energy is computed by using density functional theory (DFT) while the vertical electronic excitations are obtained by time-dependent DFT in a state-specific corrected linear response scheme. We calculate the excited state oxidation potential (ESOP) for the protonated and deprotonated forms of the L0 dye at different distances and configurations with respect to the NP surface. The stronger renormalizations of the ESOP values due to the presence of the TiO2 nanostructure are found for the protonated dye, reaching a maximum of about -0.15 eV. The role of protonation effect is discussed in terms of the atomic Löwdin charges of the oxidized and reduced species. On the other hand, we observed a weak effect on the L0 optical excitation gap due to the polarization response of the NP.

  18. Molecular surface area based predictive models for the adsorption and diffusion of disperse dyes in polylactic acid matrix.

    PubMed

    Xu, Suxin; Chen, Jiangang; Wang, Bijia; Yang, Yiqi

    2015-11-15

    Two predictive models were presented for the adsorption affinities and diffusion coefficients of disperse dyes in polylactic acid matrix. Quantitative structure-sorption behavior relationship would not only provide insights into sorption process, but also enable rational engineering for desired properties. The thermodynamic and kinetic parameters for three disperse dyes were measured. The predictive model for adsorption affinity was based on two linear relationships derived by interpreting the experimental measurements with molecular structural parameters and compensation effect: ΔH° vs. dye size and ΔS° vs. ΔH°. Similarly, the predictive model for diffusion coefficient was based on two derived linear relationships: activation energy of diffusion vs. dye size and logarithm of pre-exponential factor vs. activation energy of diffusion. The only required parameters for both models are temperature and solvent accessible surface area of the dye molecule. These two predictive models were validated by testing the adsorption and diffusion properties of new disperse dyes. The models offer fairly good predictive ability. The linkage between structural parameter of disperse dyes and sorption behaviors might be generalized and extended to other similar polymer-penetrant systems.

  19. Determination of the mass transfer limiting step of dye adsorption onto commercial adsorbent by using mathematical models.

    PubMed

    Marin, Pricila; Borba, Carlos Eduardo; Módenes, Aparecido Nivaldo; Espinoza-Quiñones, Fernando R; de Oliveira, Silvia Priscila Dias; Kroumov, Alexander Dimitrov

    2014-01-01

    Reactive blue 5G dye removal in a fixed-bed column packed with Dowex Optipore SD-2 adsorbent was modelled. Three mathematical models were tested in order to determine the limiting step of the mass transfer of the dye adsorption process onto the adsorbent. The mass transfer resistance was considered to be a criterion for the determination of the difference between models. The models contained information about the external, internal, or surface adsorption limiting step. In the model development procedure, two hypotheses were applied to describe the internal mass transfer resistance. First, the mass transfer coefficient constant was considered. Second, the mass transfer coefficient was considered as a function of the dye concentration in the adsorbent. The experimental breakthrough curves were obtained for different particle diameters of the adsorbent, flow rates, and feed dye concentrations in order to evaluate the predictive power of the models. The values of the mass transfer parameters of the mathematical models were estimated by using the downhill simplex optimization method. The results showed that the model that considered internal resistance with a variable mass transfer coefficient was more flexible than the other ones and this model described the dynamics of the adsorption process of the dye in the fixed-bed column better. Hence, this model can be used for optimization and column design purposes for the investigated systems and similar ones.

  20. Kinetics of photoinduced ordering in azo-dye films: two-state and diffusion models.

    PubMed

    Kiselev, Alexei D; Chigrinov, Vladimir G; Kwok, Hoi-Sing

    2009-07-01

    We theoretically study the kinetics of photoinduced ordering in azo-dye photoaligning layers and present the results of modeling performed using two different phenomenological approaches. A phenomenological two-state model is deduced from the master equation for the one-particle distribution functions of an ensemble of two-level molecular systems by specifying the angular redistribution probabilities and by expressing the order parameter correlation functions in terms of the order parameter tensor. Using an alternative approach that describes light-induced reorientation of azo-dye molecules in terms of a rotational Brownian motion, we formulate the two-dimensional diffusion model as the free energy Fokker-Planck equation simplified for the limiting regime of purely in-plane reorientation. The models are employed to interpret the irradiation time dependence of the absorption order parameters defined in terms of the principal extinction (absorption) coefficients. Using the exact solution to the light transmission problem for a biaxially anisotropic absorbing layer, these coefficients are extracted from the absorbance-vs-incidence angle curves measured at different irradiation doses for the probe light linearly polarized parallel and perpendicular to the plane of incidence. It is found that, in the azo-dye films, the transient photoinduced structures are biaxially anisotropic whereas the photosteady and the initial states are uniaxial.

  1. Kinetics of photoinduced ordering in azo-dye films: Two-state and diffusion models

    SciTech Connect

    Kiselev, Alexei D.; Chigrinov, Vladimir G.; Kwok, Hoi-Sing

    2009-07-15

    We theoretically study the kinetics of photoinduced ordering in azo-dye photoaligning layers and present the results of modeling performed using two different phenomenological approaches. A phenomenological two-state model is deduced from the master equation for the one-particle distribution functions of an ensemble of two-level molecular systems by specifying the angular redistribution probabilities and by expressing the order parameter correlation functions in terms of the order parameter tensor. Using an alternative approach that describes light-induced reorientation of azo-dye molecules in terms of a rotational Brownian motion, we formulate the two-dimensional diffusion model as the free energy Fokker-Planck equation simplified for the limiting regime of purely in-plane reorientation. The models are employed to interpret the irradiation time dependence of the absorption order parameters defined in terms of the principal extinction (absorption) coefficients. Using the exact solution to the light transmission problem for a biaxially anisotropic absorbing layer, these coefficients are extracted from the absorbance-vs-incidence angle curves measured at different irradiation doses for the probe light linearly polarized parallel and perpendicular to the plane of incidence. It is found that, in the azo-dye films, the transient photoinduced structures are biaxially anisotropic whereas the photosteady and the initial states are uniaxial.

  2. Equilibrium and kinetic modeling of adsorption of reactive dye on cross-linked chitosan beads.

    PubMed

    Chiou, Ming Shen; Li, Hsing Ya

    2002-07-22

    The adsorption of reactive dye (Reactive Red 189) from aqueous solutions on cross-linked chitosan beads was studied in a batch system. The equilibrium isotherms at different particle sizes (2.3-2.5, 2.5-2.7 and 3.5-3.8mm) and the kinetics of adsorption with respect to the initial dye concentration (4320, 5760 and 7286 g/m(3)), temperature (30, 40 and 50 degrees C), pH (1.0, 3.0, 6.0 and 9.0), and cross-linking ratio (cross-linking agent/chitosan weight ratio: 0.2, 0.5, 0.7 and 1.0) were investigated. Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms and isotherm constants. Equilibrium data fitted very well to the Langmuir model in the entire saturation concentration range (0-1800 g/m(3)). The maximum monolayer adsorption capacities obtained from the Langmuir model are very large, which are 1936, 1686 and 1642 g/kg for small, mediumand large particle sizes, respectively, at pH 3.0, 30 degrees C, and the cross-linking ratio of 0.2. The pseudo first- and second-order kinetic models were used to describe the kinetic data, and the rate constants were evaluated. The experimental data fitted well to the second-order kinetic model, which indicates that the chemical sorption is the rate-limiting step, instead of mass transfer. The initial dye concentration and the solution pH both significantly affect the adsorption capacity, but the temperature and the cross-linking ratio are relatively minor factors. An increase in initial dye concentration results in the increase of adsorption capacity, which also increases with decreasing pH. The activation energy is 43.0 kJ/mol for the adsorption of the dye on the cross-linked chitosan beads at pH 3.0 and initial dye concentration 3768 g/m(3).

  3. Holographic Recordings in Dye/Polymer Systems For Engineering Applications

    NASA Astrophysics Data System (ADS)

    Lessard, Roger A.; Couture, Jean J.

    1990-04-01

    Since Gabor's first demonstration of reconstructed wavefronts, many holographic techniques provided interesting tools and applications. Presently the future of holography is strongly dependent upon new holographic recording thin films. Because of their excellent responses to high spatial frequency grating recordings (up to 6800 cycles/mm), photopolymers and photocrosslinking materials seem to be good candidates to overcome some limitations. Dichromated gelatin films demons-trated excellent properties for permanent recording grating applications like HOE construction but they are humidity sensitive and they need a chemical development. Today's holographic works need real-time like recording material and law cost organic materials as DYE/POLYMER systems offer some possibilities. We present a review of research works done in our holography laboratories of COPL at Universite Laval. Using an automated spatial frequency analyzer designed at COPL, DYE/POLYMER systems are characterized for transmission holography and also for applications involving real-time holography and four-wave mixing techniques. Also, most of our characterization studies consider volume polarization holograms. The second subject is devoted to polarization hologram recordings in thin colored polyvinyl alcohol films. Those AZO/WA solid films are erasable and can be used for many thousands duty cycles for polarization volume holograms. Holographic characterization studies are conducted in order to know best experimental conditions and applications that allow to use those films. Finally, sensitized PVA films will be discussed.

  4. Supramolecular guest-host systems: combining high dye doping level with low aggregation tendency

    NASA Astrophysics Data System (ADS)

    Priimagi, Arri; Cattaneo, Stefano; Ras, Robin H. A.; Valkama, Sami; Ikkala, Olli; Kauranen, Martti

    2006-08-01

    We demonstrate that the aggregation tendency of dye molecules in a host polymer can be significantly reduced by exploiting non-covalent interactions between the host polymer and guest dye molecules. Such interactions occur spontaneously with no need for chemical synthesis, and could thus be utilized to combine the ease of processing of traditional guest-host systems with the high dye concentrations achievable in covalently linked systems. We studied the aggregation properties of the common azo-dye Disperse Red 1 in polymers with different functional groups. Compared to a nonpolar polymer (polystyrene), dye aggregation tendency is substantially reduced in polar polymer matrices containing hydrogen-bond donating [poly(vinylphenol)] or hydrogen-bond accepting [poly(4-vinylpyridine)] functional sites. Furthermore, by forming a polyelectrolyte-dye complex [Disperse Red 1/poly(styrenesulfonic acid)], a dye monomer can be attached to approximately each polymer unit, resulting in dye concentration of 63 wt. %. Complexation through proton transfer was further studied by using a fluorescent dye 5-phenyl-2-(4-pyridyl)oxazole. Our results indicate that polymer-dye complexes could provide a facile route for new type of optical materials, with potential applications in various fields of optics and photonics.

  5. Modeling the efficiency of Förster resonant energy transfer from energy relay dyes in dye-sensitized solar cells.

    PubMed

    Hoke, Eric T; Hardin, Brian E; McGehee, Michael D

    2010-02-15

    Förster resonant energy transfer can improve the spectral breadth, absorption and energy conversion efficiency of dye sensitized solar cells. In this design, unattached relay dyes absorb the high energy photons and transfer the excitation to sensitizing dye molecules by Förster resonant energy transfer. We use an analytic theory to calculate the excitation transfer efficiency from the relay dye to the sensitizing dye accounting for dynamic quenching and relay dye diffusion. We present calculations for pores of cylindrical and spherical geometry and examine the effects of the Förster radius, the pore size, sensitizing dye surface concentration, collisional quenching rate, and relay dye lifetime. We find that the excitation transfer efficiency can easily exceed 90% for appropriately chosen dyes and propose two different strategies for selecting dyes to achieve record power conversion efficiencies.

  6. Construction of a high efficiency copper adsorption bacterial system via peptide display and its application on copper dye polluted wastewater.

    PubMed

    Maruthamuthu, Murali Kannan; Nadarajan, Saravanan Prabhu; Ganesh, Irisappan; Ravikumar, Sambandam; Yun, Hyungdon; Yoo, Ik-Keun; Hong, Soon Ho

    2015-11-01

    For the construction of an efficient copper waste treatment system, a cell surface display strategy was employed. The copper adsorption ability of recombinant bacterial strains displaying three different copper binding peptides were evaluated in LB Luria-Bertani medium (LB), artificial wastewater, and copper phthalocyanine containing textile dye industry wastewater samples. Structural characteristics of the three peptides were also analyzed by similarity-based structure modeling. The best binding peptide was chosen for the construction of a dimeric peptide display and the adsorption ability of the monomeric and dimeric peptide displayed strains were compared. The dimeric peptide displayed strain showed superior copper adsorption in all three tested conditions (LB, artificial wastewater, and textile dye industry wastewater). When the strains were exposed to copper phthalocyanine dye polluted wastewater, the dimeric peptide display [543.27 µmol/g DCW dry cell weight (DCW)] showed higher adsorption of copper when compared with the monomeric strains (243.53 µmol/g DCW).

  7. Synthesis of Charge Transfer Dyes for Use as Molecular Sensors in Biological Systems

    NASA Technical Reports Server (NTRS)

    Christie, Joseph J.

    2003-01-01

    This is a continuation of last year's project to synthesize tetraaryl substituted benzodifurans for use as molecular probes in biological systems. The project will involve the synthesis and chemical characterization of dyes and precursor molecules.

  8. The excited states of stilbene and stilbenoid donor-acceptor dye systems. A theoretical study

    NASA Astrophysics Data System (ADS)

    Rettig, Wolfgang; Strehmel, Bernd; Majenz, Wilfried

    1993-07-01

    Semiempirical calculations within the CNDO/S framework are used to characterize the nature of the "phantom-singlet" excited state P * (double-bond twisted geometry) of stilbene and stilbenoid donor-acceptor dye systems including the laser dyes DCM and DASPMI. P * is highly polar (closed shell "hole-pair" nature) for weakly perturbed stilbenes but for larger donor-acceptor strength, the order of ground and excited state is reversed, and P * becomes of small polarity ("dot-dot" nature), fully consistent with the established model of biradicaloid states. For stilbene, a slight geometric symmetry reduction is necessary in order to localize the orbitals on the subunits. Only then are the calculated results consistent with those for methyl-substituted stilbene. The localized orbital description of twisted stilbene shows that P * contains negligible doubly excited character and possesses a very small gap to the ground state contrary to what is stated in the previous literature. The planar systems are also investigated and correlated with Dähne's triad rule of polymethine systems.

  9. Extractive biodecolorization of triphenylmethane dyes in cloud point system by Aeromonas hydrophila DN322p.

    PubMed

    Pan, Tao; Ren, Suizhou; Xu, Meiying; Sun, Guoping; Guo, Jun

    2013-07-01

    The biological treatment of triphenylmethane dyes is an important issue. Most microbes have limited practical application because they cannot completely detoxicate these dyes. In this study, the extractive biodecolorization of triphenylmethane dyes by Aeromonas hydrophila DN322p was carried out by introducing the cloud point system. The cloud point system is composed of a mixture of nonionic surfactants (20 g/L) Brij 30 and Tergitol TMN-3 in equal proportions. After the decolorization of crystal violet, a higher wet cell weight was obtained in the cloud point system than that of the control system. Based on the results of thin-layer chromatography, the residual crystal violet and its decolorized product, leuco crystal violet, preferred to partition into the coacervate phase. Therefore, the detoxification of the dilute phase was achieved, which indicated that the dilute phase could be discharged without causing dye pollution. The extractive biodecolorization of three other triphenylmethane dyes was also examined in this system. The decolorization of malachite green and brilliant green was similar to that of crystal violet. Only ethyl violet achieved a poor decolorization rate because DN322p decolorized it via adsorption but did not convert it into its leuco form. This study provides potential application of biological treatment in triphenylmethane dye wastewater.

  10. Spectroscopic studies of interactions between dyes and model molecules of Alzheimer's disease

    NASA Astrophysics Data System (ADS)

    Elhaddaoui, A.; Delacourte, A.; Turrell, S.

    1993-06-01

    Raman, FTIR, fluorescence, and UV-visible spectra are used to study interactions between amuloid-labelling dyes and poly-L-lysine and bovine insulin, two proteins which play the role of models of (beta) amyloid of Alzheimers disease. It is found that though the (beta) conformation of the peptide is not essential, it helps to encourage binding which appears to be stable and specific in nature, involving SO3- groups of the dyes and NH2 groups of the proteins.

  11. Modeling and characterization of dye-doped guest-host liquid crystal eyewear

    NASA Astrophysics Data System (ADS)

    Coutino, Pedro Coutino

    This thesis explores the use of dye-doped guest-host liquid crystals in variable transmission eyewear devices that protect against rapid and abrupt changes in lighting conditions. Some of their unique characteristics such as millisecond time response, low power consumption, fail-safe operation, and wide color palette make them the only available technology that meets the basic requirements for fast, adaptative eyewear applications. Despite these unique features, there are limitations in the technology which have hindered its use for more advanced eyewear applications. It is the aim of this dissertation to explore these limitations and provide experimental and numerical characterization tools necessary to surpass them. First, several techniques are described to evaluate materials and devices performance in terms of their photopic transmission, haze, birefringence, and distortion. The results are used to demonstrate that by choosing and combining the right materials, it is possible to improve the optical quality of the eyewear. Then, a simulation instrument which combines and integrates all the necessary elements to model the electro-optical response of dye-doped guest-host liquid crystal eyewear was constructed. This program is capable of reproducing with high accuracy experimental results, to predict the performance of devices, and to mimic the spectral curve of a target color. Numerical experiments were performed to study some of the most common limitations of the e-Tint mode or single cell technology including photopic transmission window, and polarization dependence and demonstrate that optimizing parameters such as birefringence, d/p, and concentration of dyes helps to overcome these limitations and enhance system performance. A guest-host double cell system is proposed as a new alternative mode for most advanced eyewear applications. Particular attention was placed on a switchable crossed polarizers configuration which offered superior optical characteristics

  12. Functional behavior of bio-electrochemical treatment system with increasing azo dye concentrations: Synergistic interactions of biocatalyst and electrode assembly.

    PubMed

    Sreelatha, S; Velvizhi, G; Naresh Kumar, A; Venkata Mohan, S

    2016-08-01

    Treatment of dye bearing wastewater through biological machinery is particularly challenging due to its recalcitrant and inhibitory nature. In this study, functional behavior and treatment efficiency of bio-electrochemical treatment (BET) system was evaluated with increasing azo dye concentrations (100, 200, 300 and 500mg dye/l). Maximum dye removal was observed at 300mg dye/l (75%) followed by 200mg dye/l (65%), 100mg dye/l (62%) and 500mg dye/l (58%). Concurrent increment in dye load resulted in enhanced azo reductase and dehydrogenase activities respectively (300mg dye/l: 39.6U; 4.96μg/ml). Derivatives of cyclic voltammograms also supported the involvement of various membrane bound redox shuttlers, viz., cytochrome-c, cytochrome-bc1 and flavoproteins during the electron transfer. Bacterial respiration during BET operation utilized various electron acceptors such as electrodes and dye intermediates with simultaneous bioelectricity generation. This study illustrates the synergistic interaction of biocatalyst with electrode assembly for efficient treatment of azo dye wastewater.

  13. Location of novel benzanthrone dyes in model membranes as revealed by resonance energy transfer.

    PubMed

    Zhytniakivska, Olga; Trusova, Valeriya; Gorbenko, Galyna; Kirilova, Elena; Kalnina, Inta; Kirilov, Georgiy; Molotkovsky, Julian; Tulkki, Jukka; Kinnunen, Paavo

    2014-05-01

    Förster resonance energy transfer (FRET) between anthrylvinyl-labeled phosphatidylcholine (AV-PC) as a donor and newly synthesized benzanthrones (referred to here as A8, A6, AM12, AM15 and AM18) as acceptors has been examined to gain insight into molecular level details of the interactions between benzanthrone dyes and model lipid membranes composed of zwitterionic lipid phosphatidylcholine and its mixtures with anionic lipids cardiolipin (CL) and phosphatidylglycerol (PG). FRET data were quantitatively analyzed in terms of the model of energy transfer in two-dimensional systems taking into account the distance dependence of orientation factor. Evidence for A8 location in phospholipid headgroup region has been obtained. Inclusion of CL and PG into PC bilayer has been found to induce substantial relocation of A6, AM12, AM15 and AM18 from hydrophobic membrane core to lipid-water interface.

  14. Insights into the Mechanism of a Covalently-Linked Organic Dye-Cobaloxime Catalyst System for Dye Sensitized Solar Fuel Devices.

    PubMed

    Pati, Palas Baran; Zhang, Lei; Philippe, Bertrand; Fernández-Terán, Ricardo; Ahmadi, Sareh; Tian, Lei; Rensmo, Håkan; Hammarström, Leif; Tian, Haining

    2017-03-24

    A covalently-linked organic dye-cobaloxime catalyst system is developed by facile click reaction for mechanistic studies and application in dye sensitized solar fuel device based on mesoporous NiO. This system has been systematically investigated by photoelectrochemical measurements, density functional theory, time resolved fluorescence, transient absorption spectroscopy as well as photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst. Moreover, they suggest that the dye adopt different structures with different excited state energies, and excitation energy transfer occurs between neighboring molecules on the semiconductor surface. The photoelectrochemical experiments also show hydrogen production by this system. The axial chloride ligands of the catalyst are released during photocatalysis in order to create the active sites for proton reduction. A working mechanism of the dye-catalyst system on photocathode is eventually proposed on the basis of this study.

  15. Circularly polarized laser emission induced in isotropic and achiral dye systems

    PubMed Central

    Cerdán, Luis; García-Moreno, Sara; Costela, Angel; García-Moreno, Inmaculada; de la Moya, Santiago

    2016-01-01

    The production of efficient, tunable, and switchable circularly polarized laser emission would have far reaching implications in optical communications or biophotonics. In this work, it is demonstrated the direct generation of circularly polarized (CP) laser emission in achiral and isotropic dye laser systems without the use of extracavity polarizing elements, and without resorting to chiral dyes, chiral liquid crystal matrices, or interferometric methods. The origin of this ellipticity arises from the dynamic birefringence induced by the strong and polarized laser pumping and the subsequent orientation anisotropy of the excited molecular dipoles. A complete polarimetric characterization of the polarization state of conventional dye laser oscillators as a function of different experimental parameters is performed and it is shown that the generated light always possesses a certain level of circularity that changes in a distinctive way with pump energy and polarization. These results demonstrate that it is possible to generate and modulate CP laser light from efficient and photostable conventional laser dyes. PMID:27350073

  16. Principal molecular axis and transition dipole moment orientations in liquid crystal systems: an assessment based on studies of guest anthraquinone dyes in a nematic host.

    PubMed

    Sims, Mark T; Abbott, Laurence C; Cowling, Stephen J; Goodby, John W; Moore, John N

    2016-12-21

    An assessment of five different definitions of the principal molecular axis along which molecules align in a nematic liquid crystal system has been made by analysing fully atomistic molecular dynamics (MD) simulations of a set of anthraquinone dyes in the cyanobiphenyl-based nematic host mixture E7. Principal molecular axes of the dyes defined by minimum moment of inertia, minimum circumference, minimum area, maximum aspect ratio, and surface tensor models were tested, and the surface tensor model was found to give the best description. Analyses of MD simulations of E7 alone showed that the surface tensor model also gave a good description of the principal molecular axes of the host molecules, suggesting that this model may be applicable more generally. Calculated dichroic order parameters of the guest-host systems were obtained by combining the surface tensor analysis with fixed transition dipole moment (TDM) orientations from time-dependent density functional theory (TD-DFT) calculations on optimised structures of the dyes, and the trend between the dyes generally matched the trend in the experimental values. Additional analyses of the guest-host simulations identified the range of conformers explored by the flexible chromophores within the dyes, and TD-DFT calculations on corresponding model structures showed that this flexibility has a significant effect on the TDM orientations within the molecular frames. Calculated dichroic order parameters that included the effects of this flexibility gave a significantly improved match with the experimental values for the more flexible dyes. Overall, the surface tensor model has been shown to provide a rationale for the experimental alignment trends that is based on molecular shape, and molecular flexibility within the chromophores has been shown to be significant for the guest-host systems: the computational approaches reported here may be used as a general aid in the predictive design of dyes with appropriate molecular

  17. Inclusion of Ethyl Acetoacetate Bearing 7-Hydroxycoumarin Dye by β-Cyclodextrin and its Cooperative Assembly with Mercury(II) Ions: Spectroscopic and Molecular Modeling Studies.

    PubMed

    Aliaga, Margarita E; Fierro, Angélica; Uribe, Iván; García-Río, Luis; Cañete, Álvaro

    2016-10-18

    The inclusion of the fluorescent organic dye, ethyl 3-(7-hydroxy-2-oxo-2H-chromen-3-yl)-3-oxopropanoate (1) by the host β-cyclodextrin (β-CD), and its response toward mercuric ions (Hg(2+) ), was studied by UV/Vis, fluorescence, and (1) H NMR spectroscopic analyses, mass spectrometry and molecular modeling studies. (1) H NMR measurements together with molecular modeling studies for dye 1 demonstrate that it exhibits two tautomeric forms (keto and enol); however, when the dye is included into the β-CD cavity, the enol form predominates. Moreover, by using spectroscopic and spectrometry techniques, a 1:1 stoichiometry was determined for the complexes formed between dye 1 (enol form) and β-CD, with a binding constant (Kb1 =1.8×10(4)  m(-1) ) and for the dye 1 (keto form)-Hg(2+) (Kb2 =2.3×10(3)  m(-1) ). Interestingly, in the presence of 1-β-CD complex and mercuric ions, a ternary supramolecular system (Hg-1-β-CD complex) was established, with a 1:1:1 stoichiometry and a Kb3 value of 4.3×10(3)  m(-1) , with the keto form of the dye being the only one present in this assembly. The three-component system provides a starting point for the development of novel and directed supramolecular assemblies.

  18. Development of Encapsulated Dye for Surface Impact Damage Indicator System.

    DTIC Science & Technology

    1987-09-01

    GROUP SUB-GROUP Composites Ultrasonics Dye Impact Microcapsules 11 04 NDE polyurethane 11 1 0Encapsulation Paint 19. ABSTRACT (Continue on reverse if...encapsulation, microencapsule incorporation into the USAF polyurethane paint, dnd initial correlation study of impact damage to impact coating indication. It is...project were to: 1. Refine the microcapsule formulation to be compatible with MIL-C-83286 paint. 2. Fabricate composite panels from isotropic graphite

  19. Interfacial Properties of a Hydrophobic Dye in the Tetrachloroethylene-Water-Glass Systems

    SciTech Connect

    Tuck, D.M.

    1999-02-23

    Interfacial effects play an important role in governing multiphase fluid behavior in porous media. Strongly hydrophobic organic dyes, used in many experimental studies to facilitate visual observation of the phase distributions, have generally been implicitly assumed to have no influence on the interfacial properties of the various phases in porous media. Sudan IV is the most commonly used dye for non-aqueous phase liquids (NAPLs) in laboratory experiments. It has also been used in at least one field experiment. The effects of this dye on the tetrachloroethylene (PCE)-water-glass system were investigated to test the assumption that the dye does not effect the interfacial properties and therefore PCE mobility. The results indicate that the dye does indeed change the interfacial relationships.The effect of the dye on the interfacial relationships is a complex function of the dye concentration, the solid phase composition, and the dynamic rate of new interface formation. The dye caused a slight (<10 percent) increase in interfacial tension at low concentrations (<0.1 g/L) and high rates of new interface formation. The dye reduced interfacial tension between PCE and water at low rates of new interface formation for all dye concentrations tested (0.00508 to 5.08 g/L). At the highest dye concentration, the PCE-water interfacial tension was significantly reduced regardless of the rate of new interface formation. The apparent interfacial tension increase at low dye concentrations is suspected to be an artifact of a low measured IFT value for the undyed PCE caused by leaching of rubber o-rings by the PCE prior to testing in the final drop-volume configuration.In addition to reducing interfacial tension, the dye was found to significantly alter the wetting relationship between PCE and water on a glass surface at and above the range of reported dye concentrations cited in the literature (1.1 to 1.7 g/L). The wetting relationship was rendered neutral from a water-wet initial

  20. Remediation of anionic dye from aqueous system using bio-adsorbent prepared by microwave activation.

    PubMed

    Sharma, Arush; Sharma, Gaurav; Naushad, Mu; Ghfar, Ayman A; Pathania, Deepak

    2017-04-07

    The present study was attempted to ascertain the possible application of activated carbon as cost effective and eco-friendly adsorbent prepared via microwave (MW) assisted chemical activation. The activated carbon was characterized using different techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and field-emission scanning electron microscope (FESEM). The various adsorption parameters have been optimized to examine the viability of activated carbon as a plausible sorbent for the remediation of Congo red (CR) dye from aquatic system. The adsorption equilibrium was interpreted using Langmuir, Freundlich and Tempkin isotherms. The equilibrium data adequately fitted to Langmuir isotherm with stronger R(2) (0.994). The maximum adsorption capacity (qm) of activated carbon was recorded to be 68.96 mg/g. Additionally, sorptional kinetic data were examined by reaction based and diffusion based models such as pseudo-first-order, pseudo-second-order, Elovich model and intra-particle diffusion, Dumwald-Wagner models, respectively. The experimental results indicated that pseudo-second-order equation and Elovich model better discuss the adsorption kinetics. The computed values of thermodynamic parameters such as free energy change (ΔG(0)), enthalpy change (ΔH(0)) and entropy change (ΔS(0)) were recorded as -3.63 kJ/mol, 42.47 kJ/mol, 152.07 J/mol K, respectively at 30°C, which accounted for favorable, spontaneous and endothermic process. The regeneration study emphasized that percentage uptake declined from 90.35 to 83.45% after 6cycles of testing. So, our findings implied that activated carbon produced from biomass must be cost-effectively used as an adsorbent for detoxifying the CR dye from industrial effluents.

  1. Triphenylmethane dyes, an alternative for mediated electronic transfer systems in glucose oxidase biofuel cells.

    PubMed

    La Rotta H, Camilo E; Ciniciato, Gustavo P M K; González, Ernesto R

    2011-05-06

    The bioelectrochemical behavior of three triphenylmethane (TPM) dyes commonly used as pH indicators, and their application in mediated electron transfer systems for glucose oxidase bioanodes in biofuel cells was investigated. Bromophenol Blue, Bromothymol Blue, Bromocresol Green were compared bioelectrochemically against two widely used mediators, benzoquinone and ferrocene carboxy aldehyde. Biochemical studies were performed in terms of enzymatic oxidation, enzyme affinity, catalytic efficiency and co-factor regeneration. The different features of the TPM dyes as mediators are determined by the characteristics in the oxidation/reduction processes studied electrochemically. The reversibility of the oxidation/reduction processes was also established through the dependence of the voltammetric peaks with the sweep rates. All three dyes showed good performances compared to the FA and BQ when evaluated in a half enzymatic fuel cell. Potentiodynamic and power response experiments showed maxima power densities of 32.8 μW cm(-2) for ferrocene carboxy aldehyde followed by similar values obtained for TPM dyes around 30 μW cm(-2) using glucose and mediator concentrations of 10 mmol L(-1) and 1.0 mmol L(-1), respectively. Since no mediator consumption was observed during the bioelectrochemical process, and also good redox re-cycled processes were achieved, the use of triphenylmethane dyes is considered to be promising compared to other mediated systems used with glucose oxidase bioanodes and/or biofuel cells.

  2. Aromatic amine degradation in a UASB/CSTR sequential system treating Congo Red dye.

    PubMed

    Işik, Mustafa; Sponza, Delia Teresa

    2003-01-01

    In this study an anaerobic (upflow anaerobic sludge blanket reactor)/aerobic (completely stirred tank reactor) sequential system was used to treat a synthetic wastewater with minerals and co-substrate together with 100-4000 mg L(-1) of Congo Red dye (Direct red 28) (CR), which is a banned azo dye in Turkey. The effect of hydraulic retention time (HRT) on the decolorization and the COD removal efficiency was investigated at constant 100 mg L(-1) Congo Red concentration. 77% of COD and 95% of color was removed at a HRT of 0.486 days and a maximum organic loading rate of 6.656 kg COD m(-3) day(-1) in the anaerobic/aerobic stage. In the continuous operations, 88% of COD, 99% of color and 91% of total aromatic amine (TAA) were removed at a HRT of 3.60 days and at a CR concentration of 4000 mg L(-1). This corresponds to an organic loading rate of 1.81 kg COD m(-3) day(-1), and a CR dye loading rate of 46.37 g dye m(-3) h(-1), respectively, in the whole system. The TAA produced under anaerobic conditions was ultimately removed in the aerobic stage, resulting in very low aromatic amine recoveries (5-18%) in the last one. Therefore the aerobic effluents exhibited higher IC50 and specific methanogenic activities (SMA) compared to anaerobic and dye containing samples, indicating the reduced toxicity.

  3. Laser beam control and diagnostic systems for the copper-pumped dye laser system at Lawrence Livermore National Laboratory

    SciTech Connect

    Bliss, E.S.; Peterson, R.L.; Salmon, J.T.; Thomas, R.A.

    1992-11-01

    The laser system described in the previous paper is used for experiments in which success requires tight tolerances on beam position, direction, and wavefront. Indeed, the optimum performance of the laser itself depends on careful delivery of copper laser light to the dye amplifiers, precise propagation of dye laser beams through restricted amplifier apertures, and accurate monitoring of laser power at key locations. This paper describes the alignment systems, wavefront correction systems, and laser diagnostics systems which ensure that the control requirements of both the laser and associated experiments are met. Because laser isotope separation processes utilize more than one wavelength, these systems monitor and control multiple wavelengths simultaneously.

  4. Use of titanium dioxide photocatalysis on the remediation of model textile wastewaters containing azo dyes.

    PubMed

    Saggioro, Enrico Mendes; Oliveira, Anabela Sousa; Pavesi, Thelma; Maia, Cátia Gil; Ferreira, Luis Filipe Vieira; Moreira, Josino Costa

    2011-12-14

    The photocatalytic degradation of two commercial textile azo dyes, namely C.I Reactive Black 5 and C.I Reactive Red 239, has been studied. TiO(2) P25 Degussa was used as catalyst and photodegradation was carried out in aqueous solution under artificial irradiation with a 125 W mercury vapor lamp. The effects of the amount of TiO(2) used, UV-light irradiation time, pH of the solution under treatment, initial concentration of the azo dye and addition of different concentrations of hydrogen peroxide were investigated. The effect of the simultaneous photodegradation of the two azo dyes was also investigated and we observed that the degradation rates achieved in mono and bi-component systems were identical. The repeatability of photocatalytic activity of the photocatalyst was also tested. After five cycles of TiO(2) reuse the rate of colour lost was still 77% of the initial rate. The degradation was followed monitoring the change of azo dye concentration by UV-Vis spectroscopy. Results show that the use of an efficient photocatalyst and the adequate selection of optimal operational parameters may easily lead to a complete decolorization of the aqueous solutions of both azo dyes.

  5. Rotational strength of dye-helix complexes as studied by a potential model theory

    NASA Astrophysics Data System (ADS)

    Kamiya, Mamoru

    1988-03-01

    The fundamental features of the induced optical activity in dye-helix complexes are clarified by the trap potential model. The effect of the potential depth on the induced rotational strength is explained in terms of the relative magnitudes of the wave-phase and helix-phase variations in the path of an electron moving along a restricted helix segment just like an exciton trapped around a dye intercalation site. The potential parameters have been optimized so as to reproduce the ionic strength effect upon the rotational strengths induced in proflavine-DNA intercalation complexes.

  6. Dye Sensitized Solar Cells for Economically Viable Photovoltaic Systems.

    PubMed

    Jung, Hyun Suk; Lee, Jung-Kun

    2013-05-16

    TiO2 nanoparticle-based dye sensitized solar cells (DSSCs) have attracted a significant level of scientific and technological interest for their potential as economically viable photovoltaic devices. While DSSCs have multiple benefits such as material abundance, a short energy payback period, constant power output, and compatibility with flexible applications, there are still several challenges that hold back large scale commercialization. Critical factors determining the future of DSSCs involve energy conversion efficiency, long-term stability, and production cost. Continuous advancement of their long-term stability suggests that state-of-the-art DSSCs will operate for over 20 years without a significant decrease in performance. Nevertheless, key questions remain in regards to energy conversion efficiency improvements and material cost reduction. In this Perspective, the present state of the field and the ongoing efforts to address the requirements of DSSCs are summarized with views on the future of DSSCs.

  7. A study of mode-locked argon ion-dye laser systems

    NASA Astrophysics Data System (ADS)

    Selfridge, R. H.

    1984-06-01

    A new argon ion dye laser double mode locking cavity is presented that allows simultaneous pulse period variation in both laser pulse trains. The predicted number of pulses are analyzed and hence the period of pulses for different cavity length adjustments. A novel approach to creating synchronous picosecond pulse trains at two wavelengths is presented. The method uses a synchronously pumped argon ion laser to cause population inversion and lasing in a mixture of rhodamine 6G and cresyl violet dye. This synchronously pumped double mode locking is simpler to implement than other two wavelength methods. The pulses produced are superior to those generated in the widely used commercial synchronously pumped systems.

  8. Development of an activated carbon-packed microbial bioelectrochemical system for azo dye degradation.

    PubMed

    Cardenas-Robles, Arely; Martinez, Eduardo; Rendon-Alcantar, Idelfonso; Frontana, Carlos; Gonzalez-Gutierrez, Linda

    2013-01-01

    A microbial bioelectrochemical reactor (BER) was employed for the degradation of azo dyes without the use of an external electron donor, using activated carbon (GAC) as a redox mediator. Contribution of pH values, open circuit potential (OCP), dye concentration and applied current were individually studied. A batch system and an upflow fixed bed bioreactor were built for analyzing the effect of the applied current on biodegradation of the azo dye Reactive Red 272. The presence of GAC (20% w/v) regulated both pH and OCP values in solution and led to a removal efficiency of 98%. Cyclic voltammetry results indicate a dependence of the electron transfer mechanism with the concentration of the azo compound. With these results, a continuous flow reactor operating with J=0.045 mA cm(-2), led to removal rates of 95% (± 3.5%) in a half-residence time of 1 hour.

  9. Consumer available permanent hair dye products cause major allergic immune activation in an animal model.

    PubMed

    Bonefeld, C M; Larsen, J M; Dabelsteen, S; Geisler, C; White, I R; Menné, T; Johansen, J D

    2010-01-01

    Background p-Phenylenediamine (PPD) and related substances are ingredients of more than two-thirds of oxidative (permanent) hair dyes currently used. Although PPD is a potent skin sensitizer in predictive assays, the extent to which permanent hair dyes sensitize humans has been questioned due to the in-use conditions, e.g. the presence of couplers in the hair dye gel and rapid oxidation using a developer. Objectives To study the skin sensitizing potential of permanent hair dyes in mice. Methods Two different permanent hair dye products containing PPD were studied in CBA mice using a modified version of the local lymph node assay. The colour gel and developer (oxidant) were tested separately and in combination. Response was measured by ear swelling and cytokine production in ear tissue and serum by enzyme-linked immunosorbent assay. The immune cellular response in the draining lymph nodes was analysed by flow cytometry. Results Application of the colour gel both alone and mixed with the developer induced skin production of interleukin (IL)-1beta, tumour necrosis factor-alpha and IL-6 as well as systemic IL-6 release. Both treatments induced B- and T-cell infiltration as well as T-cell proliferation within the draining lymph nodes. Treatment with the mixture induced at least 20% more skin inflammation, cytokine production and CD4+ T-cell activation compared with the colour gel alone. Conclusions Consumer available PPD-containing permanent hair dyes can be potent and rapid immune activators. Mixing the colour gel and developer (oxidant) increased the induction of skin inflammation compared with application of the colour gel alone.

  10. Comparison of a chimeric anti-carcinoembryonic antigen antibody conjugated with visible or near-infrared fluorescent dyes for imaging pancreatic cancer in orthotopic nude mouse models

    NASA Astrophysics Data System (ADS)

    Maawy, Ali A.; Hiroshima, Yukihiko; Kaushal, Sharmeela; Luiken, George A.; Hoffman, Robert M.; Bouvet, Michael

    2013-12-01

    The aim of this study was to evaluate a set of visible and near-infrared dyes conjugated to a tumor-specific chimeric antibody for high-resolution tumor imaging in orthotopic models of pancreatic cancer. BxPC-3 human pancreatic cancer was orthotopically implanted into pancreata of nude mice. Mice received a single intravenous injection of a chimeric anti-carcinoembryonic antigen antibody conjugated to one of the following fluorophores: 488-nm group (Alexa Fluor 488 or DyLight 488); 550-nm group (Alexa Fluor 555 or DyLight 550); 650-nm group (Alexa Fluor 660 or DyLight 650), or the 750-nm group (Alexa Fluor 750 or DyLight 755). After 24 h, the Olympus OV100 small-animal imaging system was used for noninvasive and intravital fluorescence imaging of mice. Dyes were compared with respect to depth of imaging, resolution, tumor-to-background ratio (TBR), photobleaching, and hemoglobin quenching. The longer wavelength dyes had increased depth of penetration and ability to detect the smallest tumor deposits and provided the highest TBRs, resistance to hemoglobin quenching, and specificity. The shorter wavelength dyes were more photostable. This study showed unique advantages of each dye for specific cancer imaging in a clinically relevant orthotopic model.

  11. Pre-testing in hair dye users: an assessment of the Colourstart system.

    PubMed

    Basketter, David A; English, John

    2009-01-01

    To avoid adverse reactions to allergenic ingredients, manufacturers recommend "sensitivity testing" prior to use of hair dyes. However, there is no standardised method and the recommendation is often not followed. We assessed the ability of a standardised test system from one manufacturer (Colourstart, a small skin surface water-slide transfer containing p-phenylenediamine (PPD)) for its ability to elicit a reaction in those with a previously diagnosed contact allergy to PPD, the main hair dye allergen. Thirty volunteers with diagnosed PPD allergy (10 each of 3+, 2+ and 1+) were assessed with the Colourstart system according to the manufacturer's instructions. Responses were recorded after 48h exposure. Colourstart identified 100% of those with a 3+ reaction to the diagnostic patch test, 80% of the 2+ reactors and just 10% of the 1+ reactors. Thus, Colourstart successfully identified those individuals with the greatest sensitivity to PPD, who might therefore be at risk of a severe reaction if they dyed their hair. It also identified 83% of those who reported a severe/very severe history of hair dye adverse reaction. However, its proper use and interpretation are necessary if those consumers most at risk are to have the information necessary to avoid serious adverse reactions to hair dyes.

  12. Azo dye treatment with simultaneous electricity production in an anaerobic-aerobic sequential reactor and microbial fuel cell coupled system.

    PubMed

    Li, Zhongjian; Zhang, Xingwang; Lin, Jun; Han, Song; Lei, Lecheng

    2010-06-01

    A microbial fuel cell and anaerobic-aerobic sequential reactor coupled system was used for azo dye degradation with simultaneous electricity production. Electricity was produced during the co-metabolism process of glucose and azo dye. A microorganism cultured graphite-granular cathode effectively decreased the charge transfer resistance of the cathode and yielded higher power density. Operation parameters including glucose concentration and hydraulic retention time were optimized. The results indicated that recovering electricity during a sequential aerobic-anaerobic azo dye treatment process enhanced chemical oxygen demand removal and did not decrease azo dye removal. Moreover, UV-vis spectra and GC-MS illustrated that the azo bond was cleaved biologically in the anaerobic chamber and abiotically in the aerobic chamber. The toxic intermediates, aromatic amines, were removed by aerobic treatment. Our work demonstrated that the microbial fuel cell and sequential anode-cathode reactor coupled system could be applied to achieve electricity production with simultaneous azo dye degradation.

  13. D-π-A dye system containing cyano-benzoic acid as anchoring group for dye-sensitized solar cells.

    PubMed

    Katono, Masataka; Bessho, Takeru; Meng, Sheng; Humphry-Baker, Robin; Rothenberger, Guido; Zakeeruddin, Shaik M; Kaxiras, Efthimios; Grätzel, Michael

    2011-12-06

    A D-π-A dye (KM-1) incorporating cyano-benzoic acid as a new acceptor/anchoring group has been synthesized for dye-sensitized solar cells (DSCs) with a high molar extinction coefficient of 66,700 M(-1) cm(-1) at 437 nm. Theoretical calculations show that the hydrogen bond between -CN and surface hydroxyl leads to the most stable configuration on the surface of TiO(2). In addition, the adsorption of the dye on TiO(2) follows a Brunauer-Emmett-Teller (BET) isotherm. Multilayer adsorption of KM-1 on TiO(2) seems to take place particularly at higher dye concentrations. DSC device using KM-1 reached a maximum incident photon-to-current conversion efficiency (IPCE) of 84%, with a solar to electric power conversion efficiency (PCE) of 3.3% at AM1.5 G illumination (100 mW cm(-2)). This new type of anchoring group paves a way to design new dyes that combine good visible light harvesting with strong binding to the metal oxide surface.

  14. Dye-doped cholesteric lasers: Distributed feedback and photonic bandgap lasing models

    NASA Astrophysics Data System (ADS)

    Ilchishin, Igor P.; Tikhonov, Eugene A.

    2015-05-01

    A review of authors' contributions to dye-doped cholesteric liquid crystal (CLC) lasers started from the pioneer authors' paper of 1980 in which the experimental realization of the first CLC laser is presented. Both distributed feedback (DFB) and photonics band edge lasing models are discussed for different experimental conditions. A detailed study and analysis of basic characteristics of steroidal CLC lasers with low liquid crystal optical birefringence is considered with respect to the DFB model. The manifestation of a planar texture quality and mutual orientations of directors on the substrates influencing on the lasing characteristics in steroidal CLCs have been shown and described. The reversible phototuning of the CLC laser wavelength by trans-cis transitions of photoactive components is realized. Reasons for two theoretical models' coexistence for the description of dye-doped CLC lasing is considered.

  15. Organic acids enhanced decoloration of azo dye in gas phase surface discharge plasma system.

    PubMed

    Wang, Tiecheng; Qu, Guangzhou; Ren, Jingyu; Sun, Qiuhong; Liang, Dongli; Hu, Shibin

    2016-01-25

    A gas phase surface discharge plasma combined with organic acids system was developed to enhance active species mass transfer and dye-containing wastewater treatment efficacy, with Acid Orange II (AO7) as the model pollutant. The effects of discharge voltage and various organic acid additives (acetic acid, lactic acid and nonoic acid) on AO7 decoloration efficiency were evaluated. The experimental results showed that an AO7 decoloration efficiency of approximately 69.0% was obtained within 4 min of discharge plasma treatment without organic acid addition, which was improved to 82.8%, 83.5% and 88.6% within the same treatment time with the addition of acetic acid, lactic acid and nonoic acid, respectively. The enhancement effects on AO7 decoloration efficiency could be attributed to the decrease in aqueous surface tension, improvement in bubble distribution and shape, and increase in ozone equivalent concentration. The AO7 wastewater was biodegradable after discharge plasma treatment with the addition of organic acid. AO7 decomposition intermediates were analyzed by UV-vis spectrometry and GC-MS; 2-naphthol, 1,4-benzoquinone, phthalic anhydride, coumarin, 1,2-naphthoquinone, and 2-formyl-benzoic acid were detected. A possible pathway for AO7 decomposition in this system was proposed.

  16. A home-made system for IPCE measurement of standard and dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Palma, Giuseppina; Cozzarini, Luca; Capria, Ennio; Fraleoni-Morgera, Alessandro

    2015-01-01

    A home-made system for incident photon-to-electron conversion efficiency (IPCE) characterization, based on a double-beam UV-Vis spectrophotometer, has been set up. In addition to its low cost (compared to the commercially available apparatuses), the double-beam configuration gives the advantage to measure, autonomously and with no need for supplementary equipment, the lamp power in real time, compensating possible variations of the spectral emission intensity and quality, thus reducing measurement times. To manage the optical and electronic components of the system, a custom software has been developed. Validations carried out on a common silicon-based photodiode and on a dye-sensitized solar cell confirm the possibility to adopt this system for determining the IPCE of solar cells, including dye-sensitized ones.

  17. A home-made system for IPCE measurement of standard and dye-sensitized solar cells

    SciTech Connect

    Palma, Giuseppina; Cozzarini, Luca; Capria, Ennio; Fraleoni-Morgera, Alessandro E-mail: afraleoni@units.it

    2015-01-15

    A home-made system for incident photon-to-electron conversion efficiency (IPCE) characterization, based on a double-beam UV-Vis spectrophotometer, has been set up. In addition to its low cost (compared to the commercially available apparatuses), the double-beam configuration gives the advantage to measure, autonomously and with no need for supplementary equipment, the lamp power in real time, compensating possible variations of the spectral emission intensity and quality, thus reducing measurement times. To manage the optical and electronic components of the system, a custom software has been developed. Validations carried out on a common silicon-based photodiode and on a dye-sensitized solar cell confirm the possibility to adopt this system for determining the IPCE of solar cells, including dye-sensitized ones.

  18. A home-made system for IPCE measurement of standard and dye-sensitized solar cells.

    PubMed

    Palma, Giuseppina; Cozzarini, Luca; Capria, Ennio; Fraleoni-Morgera, Alessandro

    2015-01-01

    A home-made system for incident photon-to-electron conversion efficiency (IPCE) characterization, based on a double-beam UV-Vis spectrophotometer, has been set up. In addition to its low cost (compared to the commercially available apparatuses), the double-beam configuration gives the advantage to measure, autonomously and with no need for supplementary equipment, the lamp power in real time, compensating possible variations of the spectral emission intensity and quality, thus reducing measurement times. To manage the optical and electronic components of the system, a custom software has been developed. Validations carried out on a common silicon-based photodiode and on a dye-sensitized solar cell confirm the possibility to adopt this system for determining the IPCE of solar cells, including dye-sensitized ones.

  19. Adsorption of direct dye on palm ash: kinetic and equilibrium modeling.

    PubMed

    Ahmad, A A; Hameed, B H; Aziz, N

    2007-03-06

    Palm ash, an agriculture waste residue from palm-oil industry in Malaysia, was investigated as a replacement for the current expensive methods of removing direct blue 71 dye from an aqueous solution. The experimental data were analyzed by the Langmuir and Freundlich models of adsorption. Equilibrium data fitted well with Freundlich model in the range of 50-600mg/L. The equilibrium adsorption capacity of the palm ash was determined with the Langmuir equation and found to be 400.01mg dye per gram adsorbent at 30 degrees C. The rates of adsorption were found to conform to the pseudo-second-order kinetics with good correlation. The results indicate that the palm ash could be employed as a low-cost alternative to commercial activated carbon.

  20. Tracer gauge: an automated dye dilution gauging system for ice-affected streams

    USGS Publications Warehouse

    Clow, D.W.; Fleming, A.C.

    2008-01-01

    In-stream flow protection programs require accurate, real-time streamflow data to aid in the protection of aquatic ecosystems during winter base flow periods. In cold regions, however, winter streamflow often can only be estimated because in-channel ice causes variable backwater conditions and alters the stage-discharge relation. In this study, an automated dye dilution gauging system, a tracer gauge, was developed for measuring discharge in ice-affected streams. Rhodamine WT is injected into the stream at a constant rate, and downstream concentrations are measured with a submersible fluorometer. Data loggers control system operations, monitor key variables, and perform discharge calculations. Comparison of discharge from the tracer gauge and from a Cipoletti weir during periods of extensive ice cover indicated that the root-mean-square error of the tracer gauge was 0.029 m3 s−1, or 6.3% of average discharge for the study period. The tracer gauge system can provide much more accurate data than is currently available for streams that are strongly ice affected and, thus, could substantially improve management of in-stream flow protection programs during winter in cold regions. Care must be taken, however, to test for the validity of key assumptions, including complete mixing and conservative behavior of dye, no changes in storage, and no gains or losses of water to or from the stream along the study reach. These assumptions may be tested by measuring flow-weighted dye concentrations across the stream, performing dye mass balance analyses, and evaluating breakthrough curve behavior.

  1. Accurate simulation of optical properties in dyes.

    PubMed

    Jacquemin, Denis; Perpète, Eric A; Ciofini, Ilaria; Adamo, Carlo

    2009-02-17

    Since Antiquity, humans have produced and commercialized dyes. To this day, extraction of natural dyes often requires lengthy and costly procedures. In the 19th century, global markets and new industrial products drove a significant effort to synthesize artificial dyes, characterized by low production costs, huge quantities, and new optical properties (colors). Dyes that encompass classes of molecules absorbing in the UV-visible part of the electromagnetic spectrum now have a wider range of applications, including coloring (textiles, food, paintings), energy production (photovoltaic cells, OLEDs), or pharmaceuticals (diagnostics, drugs). Parallel to the growth in dye applications, researchers have increased their efforts to design and synthesize new dyes to customize absorption and emission properties. In particular, dyes containing one or more metallic centers allow for the construction of fairly sophisticated systems capable of selectively reacting to light of a given wavelength and behaving as molecular devices (photochemical molecular devices, PMDs).Theoretical tools able to predict and interpret the excited-state properties of organic and inorganic dyes allow for an efficient screening of photochemical centers. In this Account, we report recent developments defining a quantitative ab initio protocol (based on time-dependent density functional theory) for modeling dye spectral properties. In particular, we discuss the importance of several parameters, such as the methods used for electronic structure calculations, solvent effects, and statistical treatments. In addition, we illustrate the performance of such simulation tools through case studies. We also comment on current weak points of these methods and ways to improve them.

  2. Correlated aggregate model of self-healing in dye-doped polymers

    NASA Astrophysics Data System (ADS)

    Kuzyk, Mark G.; Ramini, Shiva

    2012-10-01

    Self healing of chromophores in a dye-doped polymer after photodegradation is a counterintuitive process based on the nearly universal observation that molecular damage is a thermodynamically irreversible process. We propose a new simple model of this phenomenon that takes into account all observations, including the effects of concentration, temperature, and bystander states. Critical to this model are correlations between chromophores, perhaps mediated by the polymer, which actively favors the undamaged species in analogy to Bose-Einstein condensation. We use this model to predict the behavior of decay and recovery experiments as measured with amplified spontaneous emission and absorption spectroscopy.

  3. Demonstrations in Solute Transport Using Dyes: Part II. Modeling.

    ERIC Educational Resources Information Center

    Butters, Greg; Bandaranayake, Wije

    1993-01-01

    A solution of the convection-dispersion equation is used to describe the solute breakthrough curves generated in the demonstrations in the companion paper. Estimation of the best fit model parameters (solute velocity, dispersion, and retardation) is illustrated using the method of moments for an example data set. (Author/MDH)

  4. Discrimination between FRET and non-FRET quenching in a photochromic CdSe quantum dot/dithienylethene dye system

    NASA Astrophysics Data System (ADS)

    Dworak, Lars; Reuss, Andreas J.; Zastrow, Marc; Rück-Braun, Karola; Wachtveitl, Josef

    2014-11-01

    A photochromic Förster resonance energy transfer (FRET) system was employed to disentangle the fluorescence quenching mechanisms in quantum dot/photochromic dye hybrids. In the off-state of the dye the main quenching mechanism is FRET whereas the moderate quenching in the on-state is due to non-FRET pathways opened up upon assembly.A photochromic Förster resonance energy transfer (FRET) system was employed to disentangle the fluorescence quenching mechanisms in quantum dot/photochromic dye hybrids. In the off-state of the dye the main quenching mechanism is FRET whereas the moderate quenching in the on-state is due to non-FRET pathways opened up upon assembly. Electronic supplementary information (ESI) available: QD and DTE synthesis, preparation of the DTE/QD coupled system, TEM image of the nanocrystals and experimental details. See DOI: 10.1039/c4nr05144k

  5. Modeling Solvent Broadening on the Vibronic Spectra of a Series of Coumarin Dyes. From Implicit to Explicit Solvent Models.

    PubMed

    Cerezo, Javier; Avila Ferrer, Francisco J; Prampolini, Giacomo; Santoro, Fabrizio

    2015-12-08

    We present a protocol to estimate the solvent-induced broadening of electronic spectra based on a model that explicitly takes into account the environment embedding the solute. Starting from a classical approximation of the solvent contribution to the spectrum, the broadening arises from the spread of the excitation energies due to the fluctuation of the solvent coordinates, and it is represented as a Gaussian line shape that convolutes the vibronic spectrum of the solute. The latter is computed in harmonic approximation at room temperature with a time-dependent approach. The proposed protocol for the computation of spectral broadening exploits molecular dynamics (MD) simulations performed on the solute-solvent system, keeping the solute degrees of freedom frozen, followed by the computation of the excitation properties with a quantum mechanics/molecular mechanics (QM/MM) approach. The factors that might influence each step of the protocol are analyzed in detail, including the selection of the empirical force field (FF) adopted in the MD simulations and the QM/MM partition of the system to compute the excitation energies. The procedure is applied to a family of coumarin dyes, and the results are compared with experiments and with the predictions of a very recent work (Cerezo et al., Phys. Chem. Chem. Phys. 2015, 17, 11401-11411), where an implicit model was adopted for the solvent. The final spectra of the considered coumarins were obtained without including ad hoc phenomenological parameters and indicate that the broadenings computed with explicit and implicit models both follow the experimental trend, increasing as the polarity change from the initial to the final state increases. More in detail, the implicit model provides larger estimations of the broadening that are closer to the experimental evidence, while explicit models appear to better capture relative differences arising from different solvents or different solutes. Possible inaccuracies of the adopted

  6. Long-lived laser dye

    SciTech Connect

    Fletcher, A.N.

    1986-07-29

    A method is described of obtaining in a flashlamp pumped laser system, a long-lived flashpumped laser dye having a low threshold of lasing and a moderate output comprising the steps of: placing a dye solution comprising a laser dye, the N-methyl tosylate salt of 2-(4-pyridyl)-5-(4-methoxphenyl)oxazole, and a solvent into a laser dye cavity; screening the dye solution from ultraviolet light with an optical filter; flushing the dye solution with an inert gas; and optically pumping the dye solution with a flashlamp to produce laser emission.

  7. Simulation and modelling of charge transport in dye-sensitized solar cells based on carbon nano-tube electrodes

    NASA Astrophysics Data System (ADS)

    Gacemi, Yahia; Cheknane, Ali; Hilal, Hikmat S.

    2013-03-01

    For a better understanding of the mechanisms of dye-sensitized solar cells (DSSCs), based on carbon nano-tube (CNT) electrodes, a phenomenological model is proposed. For modelling purposes, the meso-scopic porous CNT electrode is considered as a homogeneous nano-crystalline structure with thickness L. The CNT electrode is covered with light-absorbing dye molecules, and interpenetrated by the tri-iodide (I-/I3-) redox couple. A simulation platform, designed to study coupled charge transport in such cells, is presented here. The work aims at formulating a mathematical model that describes charge transfer and charge transport within the porous CNT window electrode. The model is based on a pseudo-homogeneous active layer using drift-diffusion transport equations for free electron and ion transport. Based on solving the continuity equation for electrons, the model uses the numerical finite difference method. The numerical solution of the continuity equation produces current-voltage curves that fit the diode equation with an ideality factor of unity. The calculated current-voltage (J-V) characteristics of the illuminated idealized DSSCs (100 mW cm-2, AM1.5), and the different series resistances of the transparent conductor oxide (TCO) layer were introduced into the idealized simulated photo J-V characteristics. The results obtained are presented and discussed in this paper. Thus, for a series resistance of 4 Ω of the TCO layer, the conversion efficiency (η) was 7.49% for the CNT-based cell, compared with 6.11% for the TiO2-based cell. Two recombination kinetic models are used, the electron transport kinetics within the nano-structured CNT film, or the electron transfer rate across the CNT-electrolyte interface. The simulations indicate that both electron and ion transport properties should be considered when modelling CNT-based DSSCs and other similar systems. Unlike conventional polycrystalline solar cells which exhibit carrier recombination, which limits their

  8. Quantitative structure-property relationship modeling of Grätzel solar cell dyes.

    PubMed

    Venkatraman, Vishwesh; Åstrand, Per-Olof; Alsberg, Bjørn Kåre

    2014-01-30

    With fossil fuel reserves on the decline, there is increasing focus on the design and development of low-cost organic photovoltaic devices, in particular, dye-sensitized solar cells (DSSCs). The power conversion efficiency (PCE) of a DSSC is heavily influenced by the chemical structure of the dye. However, as far as we know, no predictive quantitative structure-property relationship models for DSSCs with PCE as one of the response variables have been reported. Thus, we report for the first time the successful application of comparative molecular field analysis (CoMFA) and vibrational frequency-based eigenvalue (EVA) descriptors to model molecular structure-photovoltaic performance relationships for a set of 40 coumarin derivatives. The results show that the models obtained provide statistically robust predictions of important photovoltaic parameters such as PCE, the open-circuit voltage (V(OC)), short-circuit current (J(SC)) and the peak absorption wavelength λ(max). Some of our findings based on the analysis of the models are in accordance with those reported in the literature. These structure-property relationships can be applied to the rational structural design and evaluation of new photovoltaic materials.

  9. Development of sustainable dye adsorption system using Nutraceutical Industrial Fennel Seed Spent - Studies with Congo Red dye.

    PubMed

    Taqui, Syed Noeman; Yahya, Rosiyah; Hassan, Aziz; Nayak, Nayan; Syed, Akheel Ahmed

    2017-01-25

    Fennel seed spent (FSS) - an inexpensive nutraceutical industrial spent has been used as an efficient biosorbent for the removal of Congo Red (CR) from aqueous media. Results show that pH of 2 - 4 and temperature of 30°C was ideal for maximum adsorption. Based on regression fitting of the data it was determined that the SIPS isotherm (R(2) = 0.994, χ(2) = 0.5) adequately described the mechanism of adsorption, suggesting that the adsorption occurs in a homogeneous layer by layer with favourable interaction between layers. Thermodynamic analysis showed that the adsorption is favourable (negative values for ΔG°) and endothermic (ΔH° = 12-20 kJ mol(-1)) for an initial dye concentration of 25, 50 and 100 ppm. The low ΔH° value indicates that the adsorption is a physical process involving weak chemical interactions like hydrogen bonds and van der Waals interactions. The kinetics revealed that the adsorption process showed pseudo second order tendencies with the equal influence of intra-particle as well as film diffusion. The SEM images of FSS show a highly fibrous matrix with a hierarchical porous structure. The FTIR analysis of the spent confirmed the presence of cellulosic and ligno-cellulosic matter giving it both hydrophilic and hydrophobic properties. The investigations indicate that FSS is a cost-effective and efficient biosorbent for the remediation of toxic Congo Red dye.

  10. Local delivery of fluorescent dye for fiber-optics confocal microscopy of the living heart

    PubMed Central

    Huang, Chao; Kaza, Aditya K.; Hitchcock, Robert W.; Sachse, Frank B.

    2014-01-01

    Fiber-optics confocal microscopy (FCM) is an emerging imaging technology with various applications in basic research and clinical diagnosis. FCM allows for real-time in situ microscopy of tissue at sub-cellular scale. Recently FCM has been investigated for cardiac imaging, in particular, for discrimination of cardiac tissue during pediatric open-heart surgery. FCM relies on fluorescent dyes. The current clinical approach of dye delivery is based on systemic injection, which is associated with high dye consumption, and adverse clinical events. In this study, we investigated approaches for local dye delivery during FCM imaging based on dye carriers attached to the imaging probe. Using three-dimensional confocal microscopy, automated bench tests, and FCM imaging we quantitatively characterized dye release of carriers composed of open-pore foam only and foam loaded with agarose hydrogel. In addition, we compared local dye delivery with a model of systemic dye delivery in the isolated perfused rodent heart. We measured the signal-to-noise ratio (SNR) of images acquired in various regions of the heart. Our evaluations showed that foam-agarose dye carriers exhibited a prolonged dye release vs. foam-only carriers. Foam-agarose dye carriers allowed reliable imaging of 5–9 lines, which is comparable to 4–8 min of continuous dye release. Our study in the living heart revealed that the SNR of FCM images using local and systemic dye delivery is not different. However, we observed differences in the imaged tissue microstructure with the two approaches. Structural features characteristic of microvasculature were solely observed for systemic dye delivery. Our findings suggest that local dye delivery approach for FCM imaging constitutes an important alternative to systemic dye delivery. We suggest that the approach for local dye delivery will facilitate clinical translation of FCM, for instance, for FCM imaging during pediatric heart surgery. PMID:25309455

  11. Local delivery of fluorescent dye for fiber-optics confocal microscopy of the living heart.

    PubMed

    Huang, Chao; Kaza, Aditya K; Hitchcock, Robert W; Sachse, Frank B

    2014-01-01

    Fiber-optics confocal microscopy (FCM) is an emerging imaging technology with various applications in basic research and clinical diagnosis. FCM allows for real-time in situ microscopy of tissue at sub-cellular scale. Recently FCM has been investigated for cardiac imaging, in particular, for discrimination of cardiac tissue during pediatric open-heart surgery. FCM relies on fluorescent dyes. The current clinical approach of dye delivery is based on systemic injection, which is associated with high dye consumption, and adverse clinical events. In this study, we investigated approaches for local dye delivery during FCM imaging based on dye carriers attached to the imaging probe. Using three-dimensional confocal microscopy, automated bench tests, and FCM imaging we quantitatively characterized dye release of carriers composed of open-pore foam only and foam loaded with agarose hydrogel. In addition, we compared local dye delivery with a model of systemic dye delivery in the isolated perfused rodent heart. We measured the signal-to-noise ratio (SNR) of images acquired in various regions of the heart. Our evaluations showed that foam-agarose dye carriers exhibited a prolonged dye release vs. foam-only carriers. Foam-agarose dye carriers allowed reliable imaging of 5-9 lines, which is comparable to 4-8 min of continuous dye release. Our study in the living heart revealed that the SNR of FCM images using local and systemic dye delivery is not different. However, we observed differences in the imaged tissue microstructure with the two approaches. Structural features characteristic of microvasculature were solely observed for systemic dye delivery. Our findings suggest that local dye delivery approach for FCM imaging constitutes an important alternative to systemic dye delivery. We suggest that the approach for local dye delivery will facilitate clinical translation of FCM, for instance, for FCM imaging during pediatric heart surgery.

  12. Effect of electrode position on azo dye removal in an up-flow hybrid anaerobic digestion reactor with built-in bioelectrochemical system

    NASA Astrophysics Data System (ADS)

    Cui, Min-Hua; Cui, Dan; Lee, Hyung-Sool; Liang, Bin; Wang, Ai-Jie; Cheng, Hao-Yi

    2016-04-01

    In this study, two modes of hybrid anaerobic digestion (AD) bioreactor with built-in BESs (electrodes installed in liquid phase (R1) and sludge phase (R2)) were tested for identifying the effect of electrodes position on azo dye wastewater treatment. Alizarin yellow R (AYR) was used as a model dye. Decolorization efficiency of R1 was 90.41 ± 6.20% at influent loading rate of 800 g-AYR/ m3·d, which was 39% higher than that of R2. The contribution of bioelectrochemical reduction to AYR decolorization (16.23 ± 1.86% for R1 versus 22.24 ± 2.14% for R2) implied that although azo dye was mainly removed in sludge zone, BES further improved the effluent quality, especially for R1 where electrodes were installed in liquid phase. The microbial communities in the electrode biofilms (dominant by Enterobacter) and sludge (dominant by Enterococcus) were well distinguished in R1, but they were similar in R2. These results suggest that electrodes installed in liquid phase in the anaerobic hybrid system are more efficient than that in sludge phase for azo dye removal, which give great inspirations for the application of AD-BES hybrid process for various refractory wastewaters treatment.

  13. Effect of electrode position on azo dye removal in an up-flow hybrid anaerobic digestion reactor with built-in bioelectrochemical system

    PubMed Central

    Cui, Min-Hua; Cui, Dan; Lee, Hyung-Sool; Liang, Bin; Wang, Ai-Jie; Cheng, Hao-Yi

    2016-01-01

    In this study, two modes of hybrid anaerobic digestion (AD) bioreactor with built-in BESs (electrodes installed in liquid phase (R1) and sludge phase (R2)) were tested for identifying the effect of electrodes position on azo dye wastewater treatment. Alizarin yellow R (AYR) was used as a model dye. Decolorization efficiency of R1 was 90.41 ± 6.20% at influent loading rate of 800 g-AYR/ m3·d, which was 39% higher than that of R2. The contribution of bioelectrochemical reduction to AYR decolorization (16.23 ± 1.86% for R1 versus 22.24 ± 2.14% for R2) implied that although azo dye was mainly removed in sludge zone, BES further improved the effluent quality, especially for R1 where electrodes were installed in liquid phase. The microbial communities in the electrode biofilms (dominant by Enterobacter) and sludge (dominant by Enterococcus) were well distinguished in R1, but they were similar in R2. These results suggest that electrodes installed in liquid phase in the anaerobic hybrid system are more efficient than that in sludge phase for azo dye removal, which give great inspirations for the application of AD-BES hybrid process for various refractory wastewaters treatment. PMID:27121278

  14. Thermodynamic study of β-cyclodextrin-dye inclusion complexes using gradient flow injection technique and molecular modeling.

    PubMed

    Izadmanesh, Y; Ghasemi, Jahan B

    2016-08-05

    Gradient flow injection technique-diode array spectrophotometry was applied for β-cyclodextrin (β-CD)-dye inclusion complex studies. A single injection of a small amount of mixed β-CD-dye solution (100μl) into the carrier solution of the dye and recording the spectra gave the titration data. The mole ratio data were calculated by calibrating the dispersion pattern using a calibrator dye (rose bengal). Model-based multivariate methods were used to analyze the spectral-mole ratio data and, as a result, estimate stability constants and concentration-spectral profiles. Reliability was tested by applying this method to study the β-CD host-guest complexes with several dyes as guest molecules. Singular value decomposition (SVD) was used to select the chemical model and reduce noise. Molecular modeling provided the ability to predict the guest conformation-orientation (posing) within the cavity of β-CD and the nature of the involved interactions. Among those dyes showing observable spectral variation, the stoichiometric ratio of β-CD: dye (and log Kf) of methyl orange, fluorescein, phenol red, 4-(2-pyridylazo) resorcinol (PAR), and crystal violet were calculated to be 1:1 (4.26±0.01), 1:1 (1.53±0.08), 1:1 (3.11±0.04), 1:1 (1.06±0.12), and 2:1 (5.27±0.03), respectively. Compared with the classical method of titration, this method is simple and fast and has the advantage of needing reduced human interference. Molecular modeling facilitates a better understanding of the type of interactions and conformation of guest molecules in the β-CD cavity. The details of the proposed method are discussed in this paper.

  15. Thermodynamic study of β-cyclodextrin-dye inclusion complexes using gradient flow injection technique and molecular modeling

    NASA Astrophysics Data System (ADS)

    Izadmanesh, Y.; Ghasemi, Jahan B.

    2016-08-01

    Gradient flow injection technique-diode array spectrophotometry was applied for β-cyclodextrin (β-CD)-dye inclusion complex studies. A single injection of a small amount of mixed β-CD-dye solution (100 μl) into the carrier solution of the dye and recording the spectra gave the titration data. The mole ratio data were calculated by calibrating the dispersion pattern using a calibrator dye (rose bengal). Model-based multivariate methods were used to analyze the spectral-mole ratio data and, as a result, estimate stability constants and concentration-spectral profiles. Reliability was tested by applying this method to study the β-CD host-guest complexes with several dyes as guest molecules. Singular value decomposition (SVD) was used to select the chemical model and reduce noise. Molecular modeling provided the ability to predict the guest conformation-orientation (posing) within the cavity of β-CD and the nature of the involved interactions. Among those dyes showing observable spectral variation, the stoichiometric ratio of β-CD: dye (and log Kf) of methyl orange, fluorescein, phenol red, 4-(2-pyridylazo) resorcinol (PAR), and crystal violet were calculated to be 1:1 (4.26 ± 0.01), 1:1 (1.53 ± 0.08), 1:1 (3.11 ± 0.04), 1:1 (1.06 ± 0.12), and 2:1 (5.27 ± 0.03), respectively. Compared with the classical method of titration, this method is simple and fast and has the advantage of needing reduced human interference. Molecular modeling facilitates a better understanding of the type of interactions and conformation of guest molecules in the β-CD cavity. The details of the proposed method are discussed in this paper.

  16. Optimization of a Raman shifted dye laser system for DIAL applications

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Chu, Zhiping; Mahon, Rita; Wilkerson, Thomas D.

    1990-01-01

    An efficient Raman shifted dye laser system that generates tunable radiation at 765 and 940 nm with a bandwidth of 0.03/cm is described. Operating a Raman cell at hydrogen pressure below 14 atm, optimum first Stokes energy conversions of 45 percent and of 37 percent at 765 and 940 nm, respectively, were recorded. Optical depth measurements made at the centers of twenty-five absorption lines in the P branch of the oxygen A band imply a high spectral purity for both the laser and the Raman shifted radiation, and thus indicate the feasibility of using the stimulated Raman scattered radiation for differential absorption lidar (DIAL) measurements.

  17. Enhanced azo dye removal through anode biofilm acclimation to toxicity in single-chamber biocatalyzed electrolysis system.

    PubMed

    Wang, You-Zhao; Wang, Ai-Jie; Liu, Wen-Zong; Sun, Qian

    2013-08-01

    Azo dye is widely used in printing and dyeing process as one of refractory wastewaters for its high chroma, stable chemical property and toxicity for aquatic organism. Biocatalyzed electrolysis system (BES) is a new developed technology to degrade organic waste in bioanode and recover recalcitrant contaminants in cathode with effective decoloration. The ion exchange membrane (IEM) separate anode and cathode for biofilm formation protection. Azo removal efficiency was up to 60.8%, but decreased to 20.5% when IEM was removed. However, expensive ion exchange membrane (IEM) not suitable for further practical application, bioelectrochemical activity of bioanode is sensitive to the toxicity of azo dye. A gradient increase of azo dye concentration was used to acclimate anode biofilm to pollutant toxicity. The azo removal efficiency can be enhanced to 73.3% in 10h reaction period after acclimation. The highest removal efficiency reached 83.7% and removal rates were increased to 8.37 from 3.04 g/h/L of dual-chamber. That indicated the feasibility for azo dye removal by single-chamber BES. The IEM cancellation not only decreased the internal resistance, but increased the current density and azo dye removal.

  18. Dye tracing techniques used to determine ground-water flow in a carbonate aquifer system near Elizabethtown, Kentucky

    USGS Publications Warehouse

    Mull, D.S.; Smoot, J.L.; Liebermann, T.D.

    1988-01-01

    Because of the vulnerability of karst aquifers to contamination and the need for water managers to know recharge areas and groundwater flow characteristics for springs and wells used for public water supply, qualitative and quantitative dye tracing techniques were used during a groundwater investigation in the Elizabethtown area, Hardin County, in north-central Kentucky. The principal aquifer in the Elizabethtown area is thick, nearly horizontal beds of limestone, and thin beds of shale of Mississippi age. As much as 65% of all water pumped for the city water supply is obtained from two springs and two wells that obtain water from these rocks. Sinkholes were classified according to their ability to funnel runoff directly into the groundwater flow system, based primarily on the nature of the swallet draining the sinkhole. The presence of bedrock in the sinkhole nearly always ensured a well defined swallet leading to the subsurface. Qualitative and quantitative dye tracing techniques and equipment are discussed in detail. Qualitative dye tracing with fluorescein dye and passive dye detectors, consisting of activated coconut charcoal identified point to point connection between representative sinkholes, sinking streams, and karst windows and the city springs and wells. Qualitative tracing confirmed the presence of infiltrated surface water from a perennial stream, Valley Creek, in water from city wells and generally confirmed the direction of groundwater flow as shown by a water level contour map. Quantitative dye tracing with rhodamin WT, automatic samplers, discharge measurements, and fluorometric analyses were used to determine flow characteristics such as traveltime for arrival of the leading edge, peak concentration, trailing edge, and persistence of the dye cloud at the spring resurgence. Analyses of the dye recovery curves for quantitative dye traces completed between the same sinkholes and a city spring, and during different flow conditions showed that the

  19. Extrapolation of systemic bioavailability assessing skin absorption and epidermal and hepatic metabolism of aromatic amine hair dyes in vitro

    SciTech Connect

    Manwaring, John; Rothe, Helga; Obringer, Cindy; Foltz, David J.; Baker, Timothy R.; Troutman, John A.; Hewitt, Nicola J.; Goebel, Carsten

    2015-09-01

    Approaches to assess the role of absorption, metabolism and excretion of cosmetic ingredients that are based on the integration of different in vitro data are important for their safety assessment, specifically as it offers an opportunity to refine that safety assessment. In order to estimate systemic exposure (AUC) to aromatic amine hair dyes following typical product application conditions, skin penetration and epidermal and systemic metabolic conversion of the parent compound was assessed in human skin explants and human keratinocyte (HaCaT) and hepatocyte cultures. To estimate the amount of the aromatic amine that can reach the general circulation unchanged after passage through the skin the following toxicokinetically relevant parameters were applied: a) Michaelis–Menten kinetics to quantify the epidermal metabolism; b) the estimated keratinocyte cell abundance in the viable epidermis; c) the skin penetration rate; d) the calculated Mean Residence Time in the viable epidermis; e) the viable epidermis thickness and f) the skin permeability coefficient. In a next step, in vitro hepatocyte K{sub m} and V{sub max} values and whole liver mass and cell abundance were used to calculate the scaled intrinsic clearance, which was combined with liver blood flow and fraction of compound unbound in the blood to give hepatic clearance. The systemic exposure in the general circulation (AUC) was extrapolated using internal dose and hepatic clearance, and C{sub max} was extrapolated (conservative overestimation) using internal dose and volume of distribution, indicating that appropriate toxicokinetic information can be generated based solely on in vitro data. For the hair dye, p-phenylenediamine, these data were found to be in the same order of magnitude as those published for human volunteers. - Highlights: • An entirely in silico/in vitro approach to predict in vivo exposure to dermally applied hair dyes • Skin penetration and epidermal conversion assessed in human

  20. Unconventional High-Performance Laser Protection System Based on Dichroic Dye-Doped Cholesteric Liquid Crystals

    PubMed Central

    Zhang, Wanshu; Zhang, Lanying; Liang, Xiao; Le Zhou; Xiao, Jiumei; Yu, Li; Li, Fasheng; Cao, Hui; Li, Kexuan; Yang, Zhou; Yang, Huai

    2017-01-01

    High-performance and cost-effective laser protection system is of crucial importance for the rapid advance of lasers in military and civilian fields leading to severe damages of human eyes and sensitive optical devices. However, it is crucially hindered by the angle-dependent protective effect and the complex preparation process. Here we demonstrate that angle-independence, good processibility, wavelength tunability, high optical density and good visibility can be effectuated simultaneously, by embedding dichroic anthraquinone dyes in a cholesteric liquid crystal matrix. More significantly, unconventional two-dimensional parabolic protection behavior is reported for the first time that in stark contrast to the existing protection systems, the overall parabolic protection behavior enables protective effect to increase with incident angles, hence providing omnibearing high-performance protection. The protective effect is controllable by dye concentration, LC cell thickness and CLC reflection efficiency, and the system can be made flexible enabling applications in flexible and even wearable protection devices. This research creates a promising avenue for the high-performance and cost-effective laser protection, and may foster the development of optical applications such as solar concentrators, car explosion-proof membrane, smart windows and polarizers. PMID:28230153

  1. Unconventional High-Performance Laser Protection System Based on Dichroic Dye-Doped Cholesteric Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Zhang, Wanshu; Zhang, Lanying; Liang, Xiao; Le Zhou; Xiao, Jiumei; Yu, Li; Li, Fasheng; Cao, Hui; Li, Kexuan; Yang, Zhou; Yang, Huai

    2017-02-01

    High-performance and cost-effective laser protection system is of crucial importance for the rapid advance of lasers in military and civilian fields leading to severe damages of human eyes and sensitive optical devices. However, it is crucially hindered by the angle-dependent protective effect and the complex preparation process. Here we demonstrate that angle-independence, good processibility, wavelength tunability, high optical density and good visibility can be effectuated simultaneously, by embedding dichroic anthraquinone dyes in a cholesteric liquid crystal matrix. More significantly, unconventional two-dimensional parabolic protection behavior is reported for the first time that in stark contrast to the existing protection systems, the overall parabolic protection behavior enables protective effect to increase with incident angles, hence providing omnibearing high-performance protection. The protective effect is controllable by dye concentration, LC cell thickness and CLC reflection efficiency, and the system can be made flexible enabling applications in flexible and even wearable protection devices. This research creates a promising avenue for the high-performance and cost-effective laser protection, and may foster the development of optical applications such as solar concentrators, car explosion-proof membrane, smart windows and polarizers.

  2. Unconventional High-Performance Laser Protection System Based on Dichroic Dye-Doped Cholesteric Liquid Crystals.

    PubMed

    Zhang, Wanshu; Zhang, Lanying; Liang, Xiao; Le Zhou; Xiao, Jiumei; Yu, Li; Li, Fasheng; Cao, Hui; Li, Kexuan; Yang, Zhou; Yang, Huai

    2017-02-23

    High-performance and cost-effective laser protection system is of crucial importance for the rapid advance of lasers in military and civilian fields leading to severe damages of human eyes and sensitive optical devices. However, it is crucially hindered by the angle-dependent protective effect and the complex preparation process. Here we demonstrate that angle-independence, good processibility, wavelength tunability, high optical density and good visibility can be effectuated simultaneously, by embedding dichroic anthraquinone dyes in a cholesteric liquid crystal matrix. More significantly, unconventional two-dimensional parabolic protection behavior is reported for the first time that in stark contrast to the existing protection systems, the overall parabolic protection behavior enables protective effect to increase with incident angles, hence providing omnibearing high-performance protection. The protective effect is controllable by dye concentration, LC cell thickness and CLC reflection efficiency, and the system can be made flexible enabling applications in flexible and even wearable protection devices. This research creates a promising avenue for the high-performance and cost-effective laser protection, and may foster the development of optical applications such as solar concentrators, car explosion-proof membrane, smart windows and polarizers.

  3. Kinetic modeling of the adsorption of basic dyes onto steam-activated bituminous coal

    SciTech Connect

    El Qada, E.N.; Allen, S.J.; Walker, G.M.

    2007-07-15

    The principal aim of this work is to investigate the mechanism of basic dye (methylene blue (MB) and basic red (BR)) adsorption onto activated carbons produced from steam-activated bituminous coal. The rate of adsorption onto various activated carbons, produced in small laboratory-scale and pilot-industrial-scale processes, was investigated under a variety of conditions. The kinetic data from these investigations were correlated to a number of adsorption models in an attempt to elucidate the mechanism of the adsorption processes. The adsorption mechanism was found to follow pseudo-second-order and intraparticle-diffusion models, with external mass transfer predominating in the first 5 min of the experiment. Filtrasorb 400 (Chemviron Carbon) exhibited the highest adsorption rate for the removal of basic dyes followed by activated carbons produced by our research group: PAC1 (activated carbon produced from Venezuelan bituminous coal in small laboratory scale using physical activation technique) and PAC2 (activated carbon produced by the steam activation of New Zealand bituminous coal on a pilot-industrial scale).

  4. A trap potential model investigation of the optical activity induced in dye-DNA intercalation complexes

    NASA Astrophysics Data System (ADS)

    Kamiya, Mamoru

    1988-02-01

    The fundamental features of the optical activity induced in dye-DNA intercalation complexes are studied by application of the trap potential model which is useful to evaluate the induced rotational strength without reference to detailed geometrical information about the intercalation complexes. The specific effect of the potential depth upon the induced optical activity is explained in terms of the relative magnitudes of the wave-phase and helix-phase variations in the path of an electron moving on a restricted helical segment just like an exciton trapped around the dye intercalation site. The parallel and perpendicular components of the induced rotational strength well reflect basic properties of the helicity effects about the longitudinal and tangential axes of the DNA helical cylinder. The trap potential model is applied to optimize the potential parameters so as to reproduce the ionic strength effect upon the optical activity induced to proflavine-DNA intercalation complexes. From relationships between the optimized potential parameters and ionic strengths, it is inferred that increase in the ionic strength contributes to the optical activity induced by the nearest-neighbour interaction between intercalated proflavine and DNA base pairs.

  5. Conical intersections, charge localization, and photoisomerization pathway selection in a minimal model of a degenerate monomethine dye.

    PubMed

    Olsen, Seth; McKenzie, Ross H

    2009-12-21

    We propose a minimal model Hamiltonian for the electronic structure of a monomethine dye, in order to describe the photoisomerization of such dyes. The model describes interactions between three diabatic electronic states, each of which can be associated with a valence bond structure. Monomethine dyes are characterized by a charge-transfer resonance; the indeterminacy of the single-double bonding structure dictated by the resonance is reflected in a duality of photoisomerization pathways corresponding to the different methine bonds. The possible multiplicity of decay channels complicates mechanistic models of the effect of the environment on fluorescent quantum yields, as well as coherent control strategies. We examine the extent and topology of intersection seams between the electronic states of the dye and how they relate to charge localization and selection between different decay pathways. We find that intersections between the S(1) and S(0) surfaces only occur for large twist angles. In contrast, S(2)/S(1) intersections can occur near the Franck-Condon region. When the molecule has left-right symmetry, all intersections are associated with con- or disrotations and never with single bond twists. For asymmetric molecules (i.e., where the bridge couples more strongly to one end) the S(2) and S(1) surfaces bias torsion about different bonds. Charge localization and torsion pathway biasing are correlated. We relate our observations with several recent experimental and theoretical results, which have been obtained for dyes with similar structure.

  6. Kinetic modeling of liquid-phase adsorption of Congo red dye using guava leaf-based activated carbon

    NASA Astrophysics Data System (ADS)

    Ojedokun, Adedamola Titi; Bello, Olugbenga Solomon

    2016-02-01

    Guava leaf, a waste material, was treated and activated to prepare adsorbent. The adsorbent was characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infra Red (FTIR) and Energy-Dispersive X-ray (EDX) techniques. The carbonaceous adsorbent prepared from guava leaf had appreciable carbon content (86.84 %). The adsorption of Congo red dye onto guava leaf-based activated carbon (GLAC) was studied in this research. Experimental data were analyzed by four different model equations: Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms and it was found to fit Freundlich equation most. Adsorption rate constants were determined using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion model equations. The results clearly showed that the adsorption of CR dye onto GLAC followed pseudo-second-order kinetic model. Intraparticle diffusion was involved in the adsorption process. The mean energy of adsorption calculated from D-R isotherm confirmed the involvement of physical adsorption. Thermodynamic parameters were obtained and it was found that the adsorption of CR dye onto GLAC was an exothermic and spontaneous process at the temperatures under investigation. The maximum adsorption of CR dye by GLAC was found to be 47.62 mg/g. The study shows that GLAC is an effective adsorbent for the adsorption of CR dye from aqueous solution.

  7. Process and kinetics of azo dye decolourization in bioelectrochemical systems: effect of several key factors

    PubMed Central

    Yang, Hou-Yun; He, Chuan-Shu; Li, Lei; Zhang, Jie; Shen, Jin-You; Mu, Yang; Yu, Han-Qing

    2016-01-01

    This study explored the influence of several key factors on the process and kinetics of azo dye decolourization in bioelectrochemical systems (BESs), including cathode potential, dissolved oxygen (DO) concentration of catholyte and biofilm formed on the cathode. The results show that azo dye methyl orange (MO) decolourization in the BES could be well described with the pseudo first-order kinetics. The MO decolourization efficiency increased from 0 to 94.90 ± 0.01% and correspondingly the reaction rate constant increased from 0 to 0.503 ± 0.001 h−1 with the decrease in cathodic electrode potential from −0.2 to −0.8 V vs Ag/AgCl. On the contrary, DO concentration of the catholyte had a negative impact on MO decolourization in the BES. When DO concentration increased from zero to 5.80 mg L−1, the MO decolourization efficiency decreased from 87.19 ± 4.73% to 27.77 ± 0.06% and correspondingly the reaction rate constant reduced from 0.207 ± 0.042 to 0.033 ± 0.007 h−1. Additionally, the results suggest that the biofilm formed on the cathode could led to an adverse rather than a positive effect on azo dye decolourization in the BES in terms of efficiency and kinetics. PMID:27270398

  8. Performance of ceramic ultrafiltration membranes and fouling behavior of a dye-polysaccharide binary system.

    PubMed

    Zuriaga-Agustí, E; Alventosa-deLara, E; Barredo-Damas, S; Alcaina-Miranda, M I; Iborra-Clar, M I; Mendoza-Roca, J A

    2014-05-01

    Ultrafiltration membrane processes have become an established technology in the treatment and reuse of secondary effluents. Nevertheless, membrane fouling arises as a major obstacle in the efficient operation of these systems. In the current study, the performance of tubular ultrafiltration ceramic membranes was evaluated according to the roles exerted by membrane pore size, transmembrane pressure and feed concentration on a binary foulant system simulating textile wastewater. For that purpose, carboxymethyl cellulose sodium salt (CMC) and an azo dye were used as colloidal and organic foulants, respectively. Results showed that a larger pore size enabled more solutes to get adsorbed into the pores, producing a sharp permeate flux decline attributed to the rapid pore blockage. Besides, an increase in CMC concentration enhanced severe fouling in the case of the tighter membrane. Concerning separation efficiency, organic matter was almost completely removed with removal efficiency above 98.5%. Regarding the dye, 93% of rejection was achieved. Comparable removal efficiencies were attributed to the dynamic membrane formed by the cake layer, which governed process performance in terms of rejection and selectivity. As a result, none of the evaluated parameters showed significant influence on separation efficiency, supporting the significant role of cake layer on filtration process.

  9. Why the Particle-in-a-Box Model Works Well for Cyanine Dyes but Not for Conjugated Polyenes

    ERIC Educational Resources Information Center

    Autschbach, Jochen

    2007-01-01

    We investigate why the particle-in-a-box (PB) model works well for calculating the absorption wavelengths of cyanine dyes and why it does not work for conjugated polyenes. The PB model is immensely useful in the classroom, but owing to its highly approximate character there is little reason to expect that it can yield quantitative agreement with…

  10. Interaction between an organic dye in water and sand packs in a flume system.

    PubMed

    Nome, Rene A; Souza, Aloisio J; Nome, Carlos A; Souza, Bruno S; Nome, Faruk; Fiedler, Haidi D

    2010-11-01

    The sorption kinetics of methylene blue (MB), a standard compound in the American Society for Testing and Materials tests, on natural sand in a batch system at a reciprocal shaking speed of 120 rpm is fast, with equilibrium and surface coverage attained in minutes. When the same experiment is carried out in a recirculating flume, adsorption is much slower, with lifetimes increasing up to several months in the flume. Sorption retardation is dependent on the diffusion coefficient of the dye and on the depth of penetration of the MB layer in sand. The experimental results suggest that, in field experiments, formation of thin films dramatically inhibits the sorption kinetics and, in a closed system, such as a lake or reservoir, contaminants will remain in the water column for long periods, with very slow penetration in the sediment layer. In rivers, the contaminant will travel farther with less penetration into the sediment layer, compared to more static systems.

  11. Electrolytes based on TEMPO-Co tandem redox systems outperform single redox systems in dye-sensitized solar cells.

    PubMed

    Cong, Jiayan; Hao, Yan; Boschloo, Gerrit; Kloo, Lars

    2015-01-01

    A new TEMPO-Co tandem redox system with TEMPO and Co(bpy)3 (2+/3+) has been investigated for the use in dye-sensitized solar cells (DSSCs). A large open-circuit voltage (VOC ) increase, from 862 mV to 965 mV, was observed in the tandem redox system, while the short-circuit current density (JSC ) was maintained. The conversion efficiency was observed to increase from 7.1 % for cells containing the single Co(bpy)3 (2+/3+) redox couple, to 8.4 % for cells containing the TEMPO-Co tandem redox system. The reason for the increase in VOC and overall efficiency is ascribed to the involvement of partial regeneration of the sensitizing dye molecules by TEMPO. This assumption can be verified through the observed much faster regeneration dynamics exhibited in the presence of the tandem system. Using the tandem redox system, the faster recombination problem of the single TEMPO redox couple is resolved and the mass-transport of the metal-complex-based electrolyte is also improved. This TEMPO-Co tandem system is so far the most efficient tandem redox electrolyte reported not involving iodine. The current results show a promising future for tandem system as replacements for single redox systems in electrolytes for DSSCs.

  12. Kinetics of a reactive dye adsorption onto dolomitic sorbents.

    PubMed

    Walker, G M; Hansen, L; Hanna, J-A; Allen, S J

    2003-05-01

    A novel wastewater treatment technique has been investigated, for reactive dye removal, in batch kinetic systems. These experimental studies have indicated that charred dolomite has the potential to act as an adsorbent for the removal of Brilliant Red reactive dye from aqueous solution. The effect of initial dye concentration, adsorbent mass:liquid volume ratio, and agitation speed on dye removal have been determined with the experimental data mathematically described using empirical external mass transfer and intra-particle diffusion models. The experimental data show conformity with an adsorption process, with the removal rate heavily dependent on both external mass transfer and intra-particle diffusion.

  13. Static and dynamic model fluorescence quenching of laser dye by carbon tetrachloride in binary mixtures.

    PubMed

    Kadadevarmath, J S; Malimath, G H; Melavanki, R M; Patil, N R

    2014-01-03

    The fluorescence quenching of laser dye namely 4,4(‴)-Bis (2-butyloctyl-oxy)-p-quaterphenyl [BIBUQ] by carbon tetrachloride has been studied in different solvent mixtures of 1-4 dioxane (DN) and acetonitrile (AN) at room temperature. The quenching is found to be appreciable and a positive deviation from linearity was observed in the Stern-Volmer plot in all the solvent mixtures. Various parameters for the quenching process have been determined by sphere of action static quenching model and finite sink approximation model. The magnitudes of these rate parameters indicate that positive deviation in the Stern-Volmer (S-V) plot is both due to static and dynamic processes.

  14. Sentinel lymph nodes detection with an imaging system using Patent Blue V dye as fluorescent tracer

    NASA Astrophysics Data System (ADS)

    Tellier, F.; Steibel, J.; Chabrier, R.; Rodier, J. F.; Pourroy, G.; Poulet, P.

    2013-03-01

    Sentinel lymph node biopsy is the gold standard to detect metastatic invasion from primary breast cancer. This method can help patients avoid full axillary chain dissection, thereby decreasing the risk of morbidity. We propose an alternative to the traditional isotopic method, to detect and map the sentinel lymph nodes. Indeed, Patent Blue V is the most widely used dye in clinical routine for the visual detection of sentinel lymph nodes. A Recent study has shown the possibility of increasing the fluorescence quantum yield of Patent Blue V, when it is bound to human serum albumin. In this study we present a preclinical fluorescence imaging system to detect sentinel lymph nodes labeled with this fluorescent tracer. The setup is composed of a black and white CCD camera and two laser sources. One excitation source with a laser emitting at 635 nm and a second laser at 785 nm to illuminate the region of interest. The prototype is operated via a laptop. Preliminary experiments permitted to determine the device sensitivity in the μmol.L-1 range as regards the detection of PBV fluorescence signals. We also present a preclinical evaluation performed on Lewis rats, during which the fluorescence imaging setup detected the accumulation and fixation of the fluorescent dye on different nodes through the skin.

  15. From force-fields to photons: MD simulations of dye-labeled nucleic acids and Monte Carlo modeling of FRET

    NASA Astrophysics Data System (ADS)

    Goldner, Lori

    2012-02-01

    Fluorescence resonance energy transfer (FRET) is a powerful technique for understanding the structural fluctuations and transformations of RNA, DNA and proteins. Molecular dynamics (MD) simulations provide a window into the nature of these fluctuations on a different, faster, time scale. We use Monte Carlo methods to model and compare FRET data from dye-labeled RNA with what might be predicted from the MD simulation. With a few notable exceptions, the contribution of fluorophore and linker dynamics to these FRET measurements has not been investigated. We include the dynamics of the ground state dyes and linkers in our study of a 16mer double-stranded RNA. Water is included explicitly in the simulation. Cyanine dyes are attached at either the 3' or 5' ends with a 3 carbon linker, and differences in labeling schemes are discussed.[4pt] Work done in collaboration with Peker Milas, Benjamin D. Gamari, and Louis Parrot.

  16. Development of new near-infrared and leuco-dye optical systems for forensic and crime fighting applications

    NASA Astrophysics Data System (ADS)

    Patonay, Gabor; Strekowski, Lucjan; Salon, Jozef; Medou-Ovono, Martial; Krutak, James J.; Leggitt, Jeffrey; Seubert, Heather; Craig, Rhonda

    2004-12-01

    New chemistry for leuco fluorescin and leuco rhodamine for latent bloodstain and fingerprint detection has been developed in our laboratories. The use of these leuco dyes results in excellent contrast for several hours. The FBI's Evidence Response Team and DNA I unit collaborated with Georgia State University to validate the new fluorescin chemistry for use in the field. In addition, several new NIR dyes have been developed in our laboratories that can be used to detect different chemical residues, e.g., pepper spray, latent fingerprint, latent blood, metal ions, or other trace evidence during crime scene investigations. Proof of principle experiments showed that NIR dyes reacting with such residues can be activated with appropriately filtered semiconductor lasers and LEDs to emit NIR fluorescence that can be observed using optimally filtered night vision intensifiers or pocket scopes, digital cameras, CCD and CMOS cameras, or other NIR detection systems. The main advantage of NIR detection is that the color of the background has very little influence on detection and that there are very few materials that would interfere by exhibiting NIR fluorescence. The use of pocket scopes permits sensitive and convenient detection. Once the residues are located, digital images of the fluorescence can be recorded and samples obtained for further analyses. NIR dyes do not interfere with subsequent follow-up or confirmation methods such as DNA or LC/MS analysis. Near-infrared absorbing dyes will be summarized along with detection mechanisms.

  17. Hair dye poisoning

    MedlinePlus

    ... temporary dyes are: Arsenic Bismuth Denatured alcohol Lead ( lead poisoning ) Mercury Pyrogallol Silver Hair dyes may contain other ... infection. Continued exposure to lead or mercury can lead to permanent brain and nervous system damage. Alternative ... References Lee DC. Hydrocarbons. In: Marx JA, Hockberger ...

  18. Conjugate systems using delocalized cationic dyes as a carrier of photosensitizers to mitochondria

    NASA Astrophysics Data System (ADS)

    You, Youngjae; Ngen, Ethel J.; Rajaputra, Pallavi

    2009-06-01

    Following Photofrin, the first generation photosensitizer, several second generation photosensitizers have been developed with improved characteristics. More recently, third generation photosensitizers are proposed to achieve higher selectivity toward cancer cells/ tumor tissue. Elevated mitochondrial membrane potential of malignant cells has tested as a tool for preferential uptake of certain photosensitizers to cancer cells. In the same line, we designed new conjugate systems where delocalized cationic moiety delivers a photosensitizer to mitochondria. To prove our concept, two prototype conjugates (TPP-Rh and TPP-AO) were prepared using two cationic dyes (Rhodamine and Acridine Orange) and a photosensitizer (tetraphenylporphyrin, TPP). The two conjugates generated singlet oxygen quite well. Interestingly, the two conjugates showed higher cellular uptake by mover than 8 times than TPP-OH as well as higher phototoxicity. In particular, TPP-Rh showed closer localization pattern to mitochondria than TPP-OH.

  19. Decolorizing and detoxifying textile wastewater, containing both soluble and insoluble dyes, in a full scale combined anaerobic/aerobic system.

    PubMed

    Frijters, C T M J; Vos, R H; Scheffer, G; Mulder, R

    2006-03-01

    The wastewater originating from the bleaching and dyeing processes in the textile factory Ten Cate Protect in Nijverdal (the Netherlands) was successfully treated in a sequential anaerobic/aerobic system. In the system, a combination of an anaerobic 70-m3 fluidized bed reactor and a 450-m3 aerobic basin with integrated tilted plate settlers, 80-95% of the color was removed. The color was largely removed in the preacidification basin and the anaerobic reactor. Color, deriving from both reactive as well as disperse, was anaerobically removed, indicating that these type of dyes were reduced to colorless products. Interestingly, the vat dyes, the anthraquinones and indigoids, which were thought to be removed mainly aerobically, were largely anaerobically decolorized. Apparently the anaerobic system is capable of effectively removing the color of both soluble as insoluble dyes. The treated effluent of the sequential anaerobic/aerobic treatment showed no toxicity towards the bioluminescent bacterium Vibrio fisheri (EC20 (95%) > 45%). Partially bypassing the anaerobic stage resulted in increased toxicity (EC20 (95%) of 9% and 14%) in the effluent of the aerobic treatment and caused significant decrease of color removal. The results of this study show a main contribution of anaerobic treatment in decolorizing and detoxifying the textile wastewater in the sequential anaerobic/aerobic system.

  20. Connections of the terminal nerve and the olfactory system in two galeomorph sharks: an experimental study using a carbocyanine dye.

    PubMed

    Yáñez, Julián; Folgueira, Mónica; Köhler, Elisabeth; Martínez, Cristina; Anadón, Ramón

    2011-11-01

    In elasmobranchs the terminal nerve courses separately from the olfactory nerve. This characteristic makes elasmobranchs excellent models to study the anatomy and function of these two systems. Here we study the neural connections of the terminal nerve and olfactory system in two sharks by experimental tracing methods using carbocyanine dyes. The main projections from the terminal nerve system (consisting of three ganglia in Scyliorhinus canicula) course ipsilaterally to the medial septal nucleus and bilaterally to the ventromedial telencephalic pallial region. Minor terminal nerve projections were also traced ipsilaterally to diencephalic and mesencephalic levels. With regard to the olfactory connections, our results show that in sharks, unlike ray-finned fishes, the primary olfactory projections are mainly restricted to the olfactory bulb. We also performed tracer application to the olfactory bulb in order to analyze the possible central neuroanatomical relationship between the projections of the terminal nerve and the olfactory bulb. In these experiments labeled neurons and fibers were observed from telencephalic to caudal mesencephalic regions. However, we observe almost no overlap between the two systems at central levels. The afferent and the putatively efferent connections of the dogfish olfactory bulb are compared with those previously reported in other elasmobranchs. The significance of the extratelencephalic secondary olfactory projections is also discussed in a comparative context.

  1. Magnetic modification of microporous carbon for dye adsorption.

    PubMed

    Kyzas, George Z; Deliyanni, Eleni A; Lazaridis, Nikolaos K

    2014-09-15

    In this study, impregnation of microporous activated carbon with magnetite was achieved by co-precipitation of iron salts onto activated carbon. The evaluation of the adsorption ability of this material was examined using the anionic dye Reactive Black 5 as model dye pollutant (adsorbate). The effect of pH, ionic strength, contact time and initial dye concentration were also studied. It was found that high pH and high ionic strength favor the adsorption of Reactive Black 5. The adsorption kinetics and isotherms were well fitted by the fractal BS model and Langmuir model, respectively. The impregnation with magnetite decreases the adsorption capacity of activated carbon. Thermal re-activation of dye-loaded activated carbons was also succeeded. The characterization of the magnetic carbons was investigated by various techniques (SEM/EDAX, VSM, BET, FTIR, XRD, DTG) revealing many possible interactions in the carbon-dye system.

  2. Dye Painting!

    ERIC Educational Resources Information Center

    Johnston, Ann

    This resource provides practical instructions for applying color and design directly to fabric. Basic information about the dye painting process is given. The guide addresses the technical aspects of fabric dye and color use and offers suggestions for fabric manipulation and dye application in order to achieve various design effects. This…

  3. Modeling materials and processes in hybrid/organic photovoltaics: from dye-sensitized to perovskite solar cells.

    PubMed

    De Angelis, Filippo

    2014-11-18

    CONSPECTUS: Over the last 2 decades, researchers have invested enormous research effort into hybrid/organic photovoltaics, leading to the recent launch of the first commercial products that use this technology. Dye-sensitized solar cells (DSCs) have shown clear advantages over competing technologies. The top certified efficiency of DSCs exceeds 11%, and the laboratory-cell efficiency is greater than 13%. In 2012, the first reports of high efficiency solid-state DSCs based on organohalide lead perovskites completely revolutionized the field. These materials are used as light absorbers in DSCs and as light-harvesting materials and electron conductors in meso-superstructured and flat heterojunction solar cells and show certified efficiencies that exceed 17%. To effectively compete with conventional photovoltaics, emerging technologies such as DSCs need to achieve higher efficiency and stability, while maintaining low production costs. Many of the advances in the DSC field have relied on the computational design and screening of new materials, with researchers examining material characteristics that can improve device performance or stability. Suitable modeling strategies allow researchers to observe the otherwise inaccessible but crucial heterointerfaces that control the operation of DSCs, offering the opportunity to develop new and more efficient materials and optimize processes. In this Account, we present a unified view of recent computational modeling research examining DSCs, illustrating how the principles and simulation tools used for these systems can also be adapted to study the emerging field of perovskite solar cells. Researchers have widely applied first-principles modeling to the DSC field and, more recently, to perovskite-based solar cells. DFT/TDDFT methods provide the basic framework to describe most of the desired materials and interfacial properties, and Car-Parrinello molecular dynamics allow researchers the further ability to sample local minima and

  4. First-principles modeling of dye-sensitized solar cells: challenges and perspectives.

    PubMed

    Labat, Frédéric; Le Bahers, Tangui; Ciofini, Ilaria; Adamo, Carlo

    2012-08-21

    Since dye-sensitized solar cells (DSSCs) appeared as a promising inexpensive alternative to the traditional silicon-based solar cells, DSSCs have attracted a considerable amount of experimental and theoretical interest. In contrast with silicon-based solar cells, DSSCs use different components for the light-harvesting and transport functions, which allow researchers to fine-tune each material and, under ideal conditions, to optimize their overall performance in assembled devices. Because of the variety of elementary components present in these cells and their multiple possible combinations, this task presents experimental challenges. The photoconversion efficiencies obtained up to this point are still low, despite the significant experimental efforts spent in their optimization. The development of a low-cost and efficient computational protocol that could qualitatively (or even quantitatively) identify the promising semiconductors, dyes, and electrolytes, as well as their assembly, could save substantial experimental time and resources. In this Account, we describe our computational approach that allows us to understand and predict the different elementary mechanisms involved in DSSC working principles. We use this computational framework to propose an in silico route for the ab initio design of these materials. Our approach relies on a unique density functional theory (DFT) based model, which allows for an accurate and balanced treatment of electronic and spectroscopic properties in different phases (such as gas, solution, or interfaces) and avoids or minimizes spurious computational effects. Using this tool, we reproduced and predicted the properties of the isolated components of the DSSC assemblies. We accessed the microscopic measurable characteristics of the cells such as the short circuit current (J(sc)) or the open circuit voltage (V(oc)), which define the overall photoconversion efficiency of the cell. The absence of empirical or material-related parameters

  5. Decoloration and mineralization of reactive dyes using electron beam irradiation, Part I: Effect of the dye structure, concentration and absorbed dose (single, binary and ternary systems)

    NASA Astrophysics Data System (ADS)

    Vahdat, Ali; Bahrami, S. Hajir; Arami, M.; Bahjat, A.; Tabakh, F.; Khairkhah, M.

    2012-07-01

    In this study, three different reactive dyes (C.I. Reactive Red 4, C.I. Reactive Blue 2 and C.I. Reactive Yellow 4) and their blend solutions were irradiated with 10 MeV electron beam. Effect of absorbed dose, dye structure and primary solution concentrations on the pH value changes, degree of decoloration and chemical oxygen demand (COD) removal of solutions were investigated. Results show that this method is effective in decomposition and decoloration of the dyes solutions. This method can be applied in mineralization of wastewater containing different dyes.

  6. Kinetics of ozone-initiated oxidation of textile dye, Amaranth in aqueous systems.

    PubMed

    Dachipally, Purnachandar; Jonnalagadda, Sreekanth B

    2011-01-01

    The ozone facilitated oxidation mechanism of water soluble azo anionic dye, amaranth (Am) was investigated monitoring the depletion kinetics of the dye spectrometrically at 521 nm. The oxidation kinetics of the dye by ozone was studied under semi-batch conditions, by bubbling ozone enriched oxygen through the aqueous reaction mixture of dye, as function of flow rate, ionic strength, [O(3)] and pH variations. With excess concentration of ozone and other reagents and low [amaranth], reaction followed pseudo-first-order kinetics with respect to the dye. Added neutral salts had marginal effect on the reaction rate and the variation of pH from 7 to 2 and 7 to 12 exerted only small increases in the reaction rate suggesting molecular ozone possibly is the principle reactive species in oxidation of dye. The reaction order with respect ozone was near unity and it varied slightly with pH and flow rate variations. The overall second-order rate constant for the reaction was (105 ± 4) M(-1) min(-1). The main oxidation products immediately after amaranth decolorization were identified. The reaction mechanism and overall rate law were proposed. After spiking the seawater, river water and wastewaters with Amaranth dye, the reaction rates and trends in BOD and COD under control and natural conditions were investigated. The rate of depletion of the dye in natural waters was relatively lower, but the ozonation process significantly decreased both the BOD and COD levels.

  7. Solid state dye laser for medical applications

    NASA Astrophysics Data System (ADS)

    Aldag, Henry R.

    1994-06-01

    The development of solid state dye lasers could lead to a major breakthrough in the cost and compactness of a medical device. Advantages include: elimination of the flow system for the gain medium; ease with which to implement wavelength agility or the replacement of a degraded rod or sheet; and toxicity and flammability become a non-issue. Dye lasers have played a role in cardiology, dermatology, and urology. Of these cardiology is of interest to Palomar. The Palomar Model 3010 flashlamp-pumped dye laser medical device was used during phase 1 FDA clinical trials to break-up blood clots that cause heart attacks, a process known as coronary laser thrombolysis. It is the objective of this research and development effort to produce solid matrix lasers that will replace liquid dye lasers in these medical specialties.

  8. A self-sufficient system for removal of synthetic dye by coupling of spore-displayed triphenylmethane reductase and glucose 1-dehydrogenase.

    PubMed

    Gao, Fen; Ding, Haitao; Xu, Xiaohong; Zhao, Yuhua

    2016-11-01

    Biodegradation of triphenylmethane dyes by microorganisms is hampered by the transport barrier imposed by cell membranes. On the other hand, cell-free systems using enzyme-based biodegradation strategy are costly. Therefore, an efficient and inexpensive approach circumventing these problems is highly desirable. Here, we constructed a self-sufficient system for synthetic dye removal by coupling of spore surface-displayed triphenylmethane reductase (TMR) and glucose 1-dehydrogenase (GDH) for the first time. Display of both TMR and GDH significantly enhanced their stability under conditions of extreme pH and temperature. These engineered spores also exhibited more robust long-term stability than their purified counterparts. Furthermore, we observed that a high ratio of spore-displayed GDH is necessary for high dye degradation efficiency. These results indicate that this continuous dye removal system with cofactor regeneration offers a promising solution for dye biodegradation applications.

  9. Biphasic reduction model for predicting the impacts of dye-bath constituents on the reduction of tris-azo dye Direct Green-1 by zero valent iron (Fe(0)).

    PubMed

    Kumar, Raja; Sinha, Alok

    2017-02-01

    Influence of common dye-bath additives, namely sodium chloride, ammonium sulphate, urea, acetic acid and citric acid, on the reductive decolouration of Direct Green 1 dye in the presence of Fe(0) was investigated. Organic acids improved dye reduction by augmenting Fe(0) corrosion, with acetic acid performing better than citric acid. NaCl enhanced the reduction rate by its 'salting out' effect on the bulk solution and by Cl(-) anion-mediated pitting corrosion of iron surface. (NH4)2SO4 induced 'salting out' effect accompanied by enhanced iron corrosion by SO4(2-) anion and buffering effect of NH4(+) improved the reduction rates. However, at 2g/L (NH4)2SO4 concentration, complexating of SO4(2-) with iron oxides decreased Fe(0) reactivity. Urea severely compromised the reduction reaction, onus to its chaotropic and 'salting in' effect in solution, and due to it masking the Fe(0) surface. Decolouration obeyed biphasic reduction kinetics (R(2)>0.993 in all the cases) exhibiting an initial rapid phase, when more than 95% dye reduction was observed, preceding a tedious phase. Maximum rapid phase reduction rate of 0.955/min was observed at pH2 in the co-presence of all dye-bath constituents. The developed biphasic model reckoned the influence of each dye-bath additive on decolouration and simulated well with the experimental data obtained at pH2.

  10. Biodegradation of direct blue 129 diazo dye by Spirodela polyrrhiza: An artificial neural networks modeling.

    PubMed

    Movafeghi, A; Khataee, A R; Moradi, Z; Vafaei, F

    2016-01-01

    Phytoremediation potential of the aquatic plant Spirodela polyrrhiza was examined for direct blue 129 (DB129) azo dye. The dye removal efficiency was optimized under the variable conditions of the operational parameters including removal time, initial dye concentration, pH, temperature and amount of plant. The study reflected the significantly enhanced dye removal efficiency of S. polyrrhiza by increasing the temperature, initial dye concentration and amount of plant. Intriguingly, artificial neural network (ANN) predicted the removal time as the most dominant parameter on DB129 removal efficiency. Furthermore, the effect of dye treatment on some physiologic indices of S. polyrrhiza including growth rate, photosynthetic pigments content, lipid peroxidation and antioxidant enzymes were studied. The results revealed a reduction in photosynthetic pigments content and in multiplication of fronds after exposure to dye solution. In contrast, malondialdehyde content as well as catalase (CAT) and peroxidase (POD) activities significantly increased that was probably due to the ability of plant to overcome oxidative stress. As a result of DB129 biodegradation, a number of intermediate compounds were identified by gas chromatography-mass spectroscopy (GC-MS) analysis. Accordingly, the probable degradation pathway of DB129 in S. polyrrhiza was postulated.

  11. Direct thermal dyes

    NASA Astrophysics Data System (ADS)

    Ehlinger, Edward

    1990-07-01

    Direct thermal dyes are members of a class of compounds referred to in the imaging industry as color formers or leuco dyes. The oldest members of that class have simple triarylmethane structures, and have been employed for years in various dyeing applications. More complex triarylmethane compounds, such as phthalides and fluorans, are now used in various imaging systems to produce color. Color is derived from all of these compounds via the same mechanism, on a molecular level. That is, an event of activation produces a highly resonating cationic system whose interaction with incident light produces reflected light of a specific color. The activation event in the case of a direct thermal system is the creation of a melt on the paper involving dye and an acidic developer. The three major performance parameters in a thermal system are background color, image density, and image stability. The three major dye physical parameters affecting thermal performance are chemical constituency, purity, and particle size. Those dyes having the best combination of characteristics which can also be manufactured economically dominate the marketplace. Manufacturing high performance dyes for the thermal market involves multi-step, convergent reaction sequences performed on large scale. Intermediates must be manufactured at the right time, and at the right quality to be useful.

  12. Enhanced degradation of azo dye by a stacked microbial fuel cell-biofilm electrode reactor coupled system.

    PubMed

    Cao, Xian; Wang, Hui; Li, Xiao-Qi; Fang, Zhou; Li, Xian-Ning

    2017-03-01

    In this study, a microbial fuel cell (MFC)-biofilm electrode reactor (BER) coupled system was established for degradation of the azo dye Reactive Brilliant Red X-3B. In this system, electrical energy generated by the MFC degrades the azo dye in the BER without the need for an external power supply, and the effluent from the BER was used as the inflow for the MFC, with further degradation. The results indicated that the X-3B removal efficiency was 29.87% higher using this coupled system than in a control group. Moreover, a method was developed to prevent voltage reversal in stacked MFCs. Current was the key factor influencing removal efficiency in the BER. The X-3B degradation pathway and the types and transfer processes of intermediate products were further explored in our system coupled with gas chromatography-mass spectrometry.

  13. Comparative study on ultrasonic assisted adsorption of dyes from single system onto Fe3O4 magnetite nanoparticles loaded on activated carbon: Experimental design methodology.

    PubMed

    Bagheri, Ahmad Reza; Ghaedi, Mehrorang; Asfaram, Arash; Bazrafshan, Ali Akbar; Jannesar, Ramin

    2017-01-01

    The present study the ultrasound assisted adsorption of dyes in single system onto Fe3O4 magnetite nanoparticles loaded on activated carbon (Fe3O4-MNPs-AC) was described following characterization and identification of this adsorbent by conventional techniques likes field emission scanning electron microscopy, transmission electron microscopy, particle-size distribution, X-ray diffraction and Fourier transform infrared spectroscopy. A central composite design in conjunction with a response surface methodology according to f-test and t-test for recognition and judgment about significant term led to construction of quadratic model which represent relation among responses and effective terms. This model has unique ability to predict adsorption data behavior over a large space around central and optimum point. Accordingly Optimum conditions for well and quantitative removal of present dyes was obtained best operation and conditions: initial SY, MB and EB dyes concentration of 15, 15 and 25mgL(-1), 4.0, 6.0 and 5.0 of pH, 360, 360 and 240s sonication time and 0.04, 0.03 and 0.032g of Fe3O4-MNPs-AC. Replication of similar experiment (N=5) guide that average removal percentage of SY, MB and EB were found to be 96.63±2.86%, 98.12±1.67% and 99.65±1.21% respectively. Good agreement and closeness of Predicted and experimental result and high adsorption capacity of dyes in short time strongly confirm high suitability of present method for waste water treatment, while easy separation of present nanoparticle and its good regeneration all support good applicability of Fe3O4-MNPs-AC for waste water treatment. The kinetic study can be represented by combination of pseudo second-order and intraparticle diffusion. The obtained maximum adsorption capacities correspond to Langmuir as best model for representation of experimental data correspond to dyes adsorption onto Fe3O4-MNPs-AC were 76.37, 78.76 and 102.00mgg(-1) for SY, MB and EB, respectively. In addition, the performance

  14. Does the position of the electron-donating nitrogen atom in the ring system influence the efficiency of a dye-sensitized solar cell? A computational study.

    PubMed

    Biswas, Abul Kalam; Barik, Sunirmal; Das, Amitava; Ganguly, Bishwajit

    2016-06-01

    We have reported a number of new metal-free organic dyes (2-6) that have cyclic asymmetric benzotripyrrole derivatives as donor groups with peripheral nitrogen atoms in the ring, fluorine and thiophene groups as π-spacers, and a cyanoacrylic acid acceptor group. Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations were employed to examine the influence of the position of the donor nitrogen atom and π-conjugation on solar cell performance. The calculated electron-injection driving force (ΔG inject), electron-regeneration driving force (ΔG regen), light-harvesting efficiency (LHE), dipole moment (μ normal), and number of electrons transferred (∆q) indicate that dyes 3, 4, and 6 have significantly higher efficiencies than reference dye 1, which exhibits high efficiency. We also extended our comparison to some other reported dyes, 7-9, which have a donor nitrogen atom in the middle of the ring system. The computed results suggest that dye 6 possesses a higher incident photon to current conversion efficiency (IPCE) than reported dyes 7-9. Thus, the use of donor groups with peripheral nitrogen atoms appears to lead to more efficient dyes than those in which the nitrogen atom is present in the middle of the donor ring system. Graphical Abstract The locations of the nitrogen atoms in the donor groups in the designed dye molecules have an important influence on DSSC efficiency.

  15. Brilliant Blue Dyes in Daily Food: How Could Purinergic System Be Affected?

    PubMed Central

    Ferreira, Leonardo Gomes Braga; Ferreira, Natiele Carla da Silva; Soares-Bezerra, Rômulo José

    2016-01-01

    Dyes were first obtained from the extraction of plant sources in the Neolithic period to produce dyed clothes. At the beginning of the 19th century, synthetic dyes were produced to color clothes on a large scale. Other applications for synthetic dyes include the pharmaceutical and food industries, which are important interference factors in our lives and health. Herein, we analyzed the possible implications of some dyes that are already described as antagonists of purinergic receptors, including special Brilliant Blue G and its derivative FD&C Blue No. 1. Purinergic receptor family is widely expressed in the body and is critical to relate to much cellular homeostasis maintenance as well as inflammation and cell death. In this review, we discuss previous studies and show purinergic signaling as an important issue to be aware of in food additives development and their correlations with the physiological functions. PMID:27833914

  16. Treatability studies with granular activated carbon (GAC) and sequencing batch reactor (SBR) system for textile wastewater containing direct dyes.

    PubMed

    Sirianuntapiboon, Suntud; Sansak, Jutarat

    2008-11-30

    The GAC-SBR efficiency was decreased with the increase of dyestuff concentration or the decrease of bio-sludge concentration. The system showed the highest removal efficiency with synthetic textile wastewater (STWW) containing 40 mg/L direct red 23 or direct blue 201 under MLSS of 3,000 mg/L and hydraulic retention time (HRT) of 7.5 days. But, the effluent NO(3)(-) was higher than that of the influent. Direct red 23 was more effective than direct blue 201 to repress the GAC-SBR system efficiency. The dyes removal efficiency of the system with STWW containing direct red 23 was reduced by 30% with the increase of direct red 23 from 40 mg/L to 160 mg/L. The system with raw textile wastewater (TWW) showed quite low BOD(5) TKN and dye removal efficiencies of only 64.7+/-4.9% and 50.2+/-6.9%, respectively. But its' efficiencies could be increased by adding carbon sources (BOD(5)). The dye removal efficiency with TWW was increased by 30% and 20% by adding glucose (TWW+glucose) or Thai rice noodle wastewater (TWW+TRNWW), respectively. SRT of the systems were 28+/-1 days and 31+/-2 days with TWW+glucose and TWW+TRNWW, respectively.

  17. Artificial neural network (ANN) method for modeling of sunset yellow dye adsorption using zinc oxide nanorods loaded on activated carbon: Kinetic and isotherm study

    NASA Astrophysics Data System (ADS)

    Maghsoudi, M.; Ghaedi, M.; Zinali, A.; Ghaedi, A. M.; Habibi, M. H.

    2015-01-01

    In this research, ZnO nanoparticle loaded on activated carbon (ZnO-NPs-AC) was synthesized simply by a low cost and nontoxic procedure. The characterization and identification have been completed by different techniques such as SEM and XRD analysis. A three layer artificial neural network (ANN) model is applicable for accurate prediction of dye removal percentage from aqueous solution by ZnO-NRs-AC following conduction of 270 experimental data. The network was trained using the obtained experimental data at optimum pH with different ZnO-NRs-AC amount (0.005-0.015 g) and 5-40 mg/L of sunset yellow dye over contact time of 0.5-30 min. The ANN model was applied for prediction of the removal percentage of present systems with Levenberg-Marquardt algorithm (LMA), a linear transfer function (purelin) at output layer and a tangent sigmoid transfer function (tansig) in the hidden layer with 6 neurons. The minimum mean squared error (MSE) of 0.0008 and coefficient of determination (R2) of 0.998 were found for prediction and modeling of SY removal. The influence of parameters including adsorbent amount, initial dye concentration, pH and contact time on sunset yellow (SY) removal percentage were investigated and optimal experimental conditions were ascertained. Optimal conditions were set as follows: pH, 2.0; 10 min contact time; an adsorbent dose of 0.015 g. Equilibrium data fitted truly with the Langmuir model with maximum adsorption capacity of 142.85 mg/g for 0.005 g adsorbent. The adsorption of sunset yellow followed the pseudo-second-order rate equation.

  18. Artificial neural network (ANN) method for modeling of sunset yellow dye adsorption using zinc oxide nanorods loaded on activated carbon: Kinetic and isotherm study.

    PubMed

    Maghsoudi, M; Ghaedi, M; Zinali, A; Ghaedi, A M; Habibi, M H

    2015-01-05

    In this research, ZnO nanoparticle loaded on activated carbon (ZnO-NPs-AC) was synthesized simply by a low cost and nontoxic procedure. The characterization and identification have been completed by different techniques such as SEM and XRD analysis. A three layer artificial neural network (ANN) model is applicable for accurate prediction of dye removal percentage from aqueous solution by ZnO-NRs-AC following conduction of 270 experimental data. The network was trained using the obtained experimental data at optimum pH with different ZnO-NRs-AC amount (0.005-0.015 g) and 5-40 mg/L of sunset yellow dye over contact time of 0.5-30 min. The ANN model was applied for prediction of the removal percentage of present systems with Levenberg-Marquardt algorithm (LMA), a linear transfer function (purelin) at output layer and a tangent sigmoid transfer function (tansig) in the hidden layer with 6 neurons. The minimum mean squared error (MSE) of 0.0008 and coefficient of determination (R(2)) of 0.998 were found for prediction and modeling of SY removal. The influence of parameters including adsorbent amount, initial dye concentration, pH and contact time on sunset yellow (SY) removal percentage were investigated and optimal experimental conditions were ascertained. Optimal conditions were set as follows: pH, 2.0; 10 min contact time; an adsorbent dose of 0.015 g. Equilibrium data fitted truly with the Langmuir model with maximum adsorption capacity of 142.85 mg/g for 0.005 g adsorbent. The adsorption of sunset yellow followed the pseudo-second-order rate equation.

  19. Functiogenesis of the embryonic central nervous system revealed by optical recording with a voltage-sensitive dye.

    PubMed

    Sato, Katsushige; Momose-Sato, Yoko

    2017-01-01

    Clarification of the functiogenesis of the embryonic central nervous system (CNS) has long been problematic, because conventional electrophysiological techniques have several limitations. First, early embryonic neurons are small and fragile, and the application of microelectrodes is challenging. Second, the simultaneous monitoring of electrical activity from multiple sites is limited, and as a consequence, spatiotemporal response patterns of neural networks cannot be assessed. We have applied multiple-site optical recording with a voltage-sensitive dye to the embryonic CNS and paved a new way to analyze the functiogenesis of the CNS. In this review, we discuss key points of optical recording in the embryonic CNS and introduce recent progress in optical investigations on the embryonic CNS with special emphasis on the development of the chick olfactory system. The studies clearly demonstrate the usefulness of voltage-sensitive dye recording as a powerful tool for elucidating the functional organization of the vertebrate embryonic CNS.

  20. Dye removal using modified copper ferrite nanoparticle and RSM analysis.

    PubMed

    Mahmoodi, Niyaz Mohammad; Soltani-Gordefaramarzi, Sajjad; Sadeghi-Kiakhani, Moosa

    2013-12-01

    In this paper, copper ferrite nanoparticle (CFN) was synthesized, modified by cetyl trimethylammonium bromide, and characterized. Dye removal ability of the surface modified copper ferrite nanoparticle (SMCFN) from single system was investigated. The physical characteristics of SMCFN were studied using Fourier transform infrared, scanning electron microscopy, and X-ray diffraction. Acid Blue 92, Direct Green 6, Direct Red 23, and Direct Red 80 were used as model compounds. The effect of operational parameters (surfactant concentration, adsorbent dosage, dye concentration, and pH) on dye removal was evaluated. Response surface methodology (RSM) was used for the analysis of the dye removal data. The experimental checking in these optimal conditions confirms good agreements with RSM results. The results showed that the SMCFN being a magnetic adsorbent might be a suitable alternative to remove dyes from colored aqueous solutions.

  1. Decolorization of Solophenyl Red 3BL Polyazo Dye by Laccase-Mediator System: Optimization through Response Surface Methodology

    PubMed Central

    Neifar, Mohamed; Jaouani, Atef; Kamoun, Amel; Ellouze-Ghorbel, Raoudha; Ellouze-Chaabouni, Semia

    2011-01-01

    The decolorization of direct Solophenyl red 3BL (SR), a polyazo dye extensively used in textile industry was studied. The Fomes fomentarius laccase alone did not decolorize SR. The natural redox mediator, acetosyringone (AS), was necessary for decolorization to occur. Box-Behnken design was used to evaluate the effects of three parameters, namely, enzyme concentration (0.5–2.5 U mL−1), redox mediator concentration (3–30 μM), and incubation time (1–24 h), on the SR decolorization yield. The fitted mathematical model allowed us to plot response surfaces as well as isoresponse curves and to determine optimal decolorization conditions. The results clearly indicated that the AS concentration was the main factor influencing the SR decolorization yield. The selected optimal conditions were enzyme concentration 0.8 U mL−1, mediator concentration 33 μM, and time 14 h 30 min. These conditions allowed 79.66% of SR decolorization versus 80.70% for the predicted value. These results showed a promising future of applying laccase-AS system for industrial wastewater bioremediation. PMID:21869923

  2. Spectrophotometric investigation of the interactions between cationic (C.I. Basic Blue 9) and anionic (C.I. Acid Blue 25) dyes in adsorption onto extracted cellulose from Posidonia oceanic in single and binary system.

    PubMed

    Ben Douissa, Najoua; Dridi-Dhaouadi, Sonia; Mhenni, Mohamed Farouk

    2016-01-01

    Extracted cellulose from Posidonia oceanica was used as an adsorbent for removal of a cationic (Basic blue 9, BB) and anionic textile dye (Acid blue 25, AB) from aqueous solution in single dye system. Characterization of the extracted cellulose and extracted cellulose-dye systems were performed using several techniques such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential and Boehm acid-base titration method. Adsorption tests showed that the extracted cellulose presented higher adsorption of BB than AB in single dye system, revealing that electrostatic interactions are responsible, in the first instance, for the dye-adsorbent interaction. In single dye systems, the extracted cellulose presented the maximum adsorption capacities of BB and AB at 0.955 mmol.g(-1) and 0.370 mmol.g(-1), respectively. Adsorption experiments of AB dye on extracted cellulose saturated by BB dye exhibited the release of the latter dye from the sorbent which lead to dye-dye interaction in aqueous solution due to electrostatic attraction between both species. Interaction of BB and AB dyes were investigated using spectrophotometric analysis and results demonstrated the formation of a molecular complex detected at wavelengths 510 and 705 nm when anionic (AB) and cationic (BB) dye were taken in equimolar proportions. The adsorption isotherm of AB, taking into account the dye-dye interaction was investigated and showed that BB dye was released proportionately by AB equilibrium concentration. It was also observed that AB adsorption is widely enhanced when the formation of the molecular complex is disadvantaged.

  3. Tumor implantation model for rapid testing of lymphatic dye uptake from paw to node in small animals

    NASA Astrophysics Data System (ADS)

    DSouza, Alisha V.; Elliott, Jonathan T.; Gunn, Jason R.; Barth, Richard J.; Samkoe, Kimberley S.; Tichauer, Kenneth M.; Pogue, Brian W.

    2015-03-01

    Morbidity and complexity involved in lymph node staging via surgical resection and biopsy calls for staging techniques that are less invasive. While visible blue dyes are commonly used in locating sentinel lymph nodes, since they follow tumor-draining lymphatic vessels, they do not provide a metric to evaluate presence of cancer. An area of active research is to use fluorescent dyes to assess tumor burden of sentinel and secondary lymph nodes. The goal of this work was to successfully deploy and test an intra-nodal cancer-cell injection model to enable planar fluorescence imaging of a clinically relevant blue dye, specifically methylene blue - used in the sentinel lymph node procedure - in normal and tumor-bearing animals, and subsequently segregate tumor-bearing from normal lymph nodes. This direct-injection based tumor model was employed in athymic rats (6 normal, 4 controls, 6 cancer-bearing), where luciferase-expressing breast cancer cells were injected into axillary lymph nodes. Tumor presence in nodes was confirmed by bioluminescence imaging before and after fluorescence imaging. Lymphatic uptake from the injection site (intradermal on forepaw) to lymph node was imaged at approximately 2 frames/minute. Large variability was observed within each cohort.

  4. Optical modeling-assisted characterization of dye-sensitized solar cells using TiO2 nanotube arrays as photoanodes

    PubMed Central

    Kim, Il Ku; Wang, Lianzhou; Amal, Rose

    2014-01-01

    Summary Photovoltaic characteristics of dye-sensitized solar cells (DSSCs) using TiO2 nanotube (TNT) arrays as photoanodes were investigated. The TNT arrays were 3.3, 11.5, and 20.6 μm long with the pore diameters of 50, 78.6, and 98.7 nm, respectively. The longest TNT array of 20.6 μm in length showed enhanced photovoltaic performances of 3.87% with significantly increased photocurrent density of 8.26 mA·cm−2. This improvement is attributed to the increased amount of the adsorbed dyes and the improved electron transport property with an increase in TNT length. The initial charge generation rate was improved from 4 × 1021 s−1·cm−3 to 7 × 1021 s−1·cm−3 in DSSCs based on optical modelling analysis. The modelling analysis of optical processes inside TNT-based DSSCs using generalized transfer matrix method (GTMM) revealed that the amount of dye and TNT lengths were critical factors influencing the performance of DSSCs, which is consistent with the experimental results. PMID:24991527

  5. Near Infrared Heptamethine Cyanine Dye-Mediated Cancer Imaging*

    PubMed Central

    Yang, Xiaojian; Shi, Chunmeng; Tong, Rong; Qian, Weiping; Zhau, Haiyen E.; Wang, Ruoxiang; Zhu, Guodong; Cheng, Jianjun; Yang, Vincent W.; Cheng, Tianmin; Henary, Maged; Strekowski, Lucjan; Chung, Leland W.K.

    2010-01-01

    Purpose Near-infrared (NIR) fluorescence imaging has great potential for noninvasive in vivo imaging of tumors. In this study, we demonstrate the preferential uptake and retention of two hepatamethine cyanine dyes, IR-783 and MHI-148, in tumor cells and tissues. Experimental Design IR-783 and MHI-148 were investigated for their ability to accumulate in human cancer cells, tumor xenografts and spontaneous mouse tumors in transgenic animals. Time- and concentration-dependent dye uptake and retention in normal and cancer cells and tissues were compared, and subcellular localization of the dyes and mechanisms of the dye uptake and retention in tumor cells were evaluated using organelle-specific tracking dyes and bromosulfophthalein (BSP), a competitive inhibitor of organic anion transporting peptides (OATPs). These dyes were used to detect human cancer metastases in a mouse model and differentiate cancer cells from normal cells in blood. Results These NIR hepatamethine cyanine dyes were retained in cancer cells but not normal cells, in tumor xenografts, and in spontaneous tumors in transgenic mice. They can be used to detect cancer metastasis and cancer cells in blood with a high degree of sensitivity. The dyes were found to concentrate in the mitochondria and lysosomes of cancer cells, probably through OATPs since the dye uptake and retention in cancer cells can be blocked completely by BSP. These dyes, when injected to mice, did not cause systemic toxicity. Conclusions These two heptamethine cyanine dyes are promising imaging agents for human cancers and can be further exploited to improve cancer detection, prognosis and treatment. PMID:20410058

  6. Optical fibre spectroscopy sensor for the quantitative determination of industrial textile dyes

    NASA Astrophysics Data System (ADS)

    Cubillas, Ana M.; Conde, Olga M.; Anuarbe, Pedro; Gutierrez, Monica; Martinez, Vicente; Lopez-Higuera, Jose M.

    2009-10-01

    In this paper, an extrinsic optical fibre sensor (OFS) for the quantitative determination of dyes used in the textile industry is presented. The system proposed is based on absorption spectroscopy and multivariate calibration methods to infer the concentration of different textile dyes. The performance of the sensor has been successfully assessed using calibrated dyes, with a very good correlation between the multivariate calibration models and the predicted values. The sensor system here demonstrated could be used to predict the colour of dye mixtures during the dyebath and, therefore, reduce the manufacturing costs.

  7. Analysis of the phosphorescent dye concentration dependence of triplet-triplet annihilation in organic host-guest systems

    NASA Astrophysics Data System (ADS)

    Zhang, L.; van Eersel, H.; Bobbert, P. A.; Coehoorn, R.

    2016-10-01

    Using a novel method for analyzing transient photoluminescence (PL) experiments, a microscopic description is obtained for the dye concentration dependence of triplet-triplet annihilation (TTA) in phosphorescent host-guest systems. It is demonstrated that the TTA-mechanism, which could be a single-step dominated process or a diffusion-mediated multi-step process, can be deduced for any given dye concentration from a recently proposed PL intensity analysis. A comparison with the results of kinetic Monte Carlo simulations provides the TTA-Förster radius and shows that the TTA enhancement due to triplet diffusion can be well described in a microscopic manner assuming Förster- or Dexter-type energy transfer.

  8. Human systemic exposure to [¹⁴C]-paraphenylenediamine-containing oxidative hair dyes: Absorption, kinetics, metabolism, excretion and safety assessment.

    PubMed

    Nohynek, Gerhard J; Skare, Julie A; Meuling, Wim J A; Wehmeyer, Kenneth R; de Bie, Albertus Th H J; Vaes, Wouter H J; Dufour, Eric K; Fautz, Rolf; Steiling, Winfried; Bramante, Mario; Toutain, Herve

    2015-07-01

    Systemic exposure was measured in humans after hair dyeing with oxidative hair dyes containing 2.0% (A) or 1.0% (B) [(14)C]-p-phenylenediamine (PPD). Hair was dyed, rinsed, dried, clipped and shaved; blood and urine samples were collected for 48 hours after application. [(14)C] was measured in all materials, rinsing water, hair, plasma, urine and skin strips. Plasma and urine were also analysed by HLPC/MS/MS for PPD and its metabolites (B). Total mean recovery of radioactivity was 94.30% (A) or 96.21% (B). Mean plasma Cmax values were 132.6 or 97.4 ng [(14)C]-PPDeq/mL, mean AUC(0-∞) values 1415 or 966 ng [(14)C]-PPDeq/mL*hr in studies A or B, respectively. Urinary excretion of [(14)C] mainly occurred within 24 hrs after hair colouring with a total excretion of 0.72 or 0.88% of applied radioactivity in studies A or B, respectively. Only N,N'-diacetylated-PPD was detected in plasma and the urine. A TK-based human safety assessment estimated margins of safety of 23.3- or 65-fold relative to respective plasma AUC or Cmax values in rats at the NOAEL of a toxicity study. Overall, hair dyes containing PPD are unlikely to pose a health risk since they are used intermittently and systemic exposure is limited to the detoxified metabolite N,N'-diacetyl-PPD.

  9. A study of dyes sorption on biobased cryogels

    NASA Astrophysics Data System (ADS)

    Dobritoiu, Rodica; Patachia, Silvia

    2013-11-01

    Three types of biopolymers based materials were synthesized and tested as adsorbents for the dyes from aqueous solutions. Blends based on poly (vinyl alcohol) [PVA] and scleroglucan [Scl], cellulose micro-fibres [cel] and zein, respectively, have been prepared by repeated freezing-thawing cycles. Methylene blue [MB] was selected as a model dye in order to evaluate the capacity of the prepared materials to remove the dyes from aqueous solutions. The effects of the initial dye concentration, contact time and the composition of materials on the kinetic and thermodynamic parameters of sorption were discussed. The pseudo-second-order kinetics was found to better fit the experimental data thus being able to consistently predict the amount of dye adsorbed over the entire sorption period. The sorption equilibrium data obey Freundlich isotherm. Sorption capacity was evaluated both by dye solution and cryogel analysis by using VIS spectrometry and image analysis with CIELAB system. The sorption of monomer or aggregated dye molecules was identified and correlated with the type and morphology of the gel. The highest efficiency in MB removal was obtained for Scl/PVA cryogels in 1:9 weight ratio (9.5279 mg/g MB for an initial concentration by 8 × 10-5 mol/L in MB). These materials are suitable as sorbents for the advanced removal of dyes from waste water.

  10. Dye lasers. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Cavagnaro, D. M.

    1980-08-01

    Studies on dye laser theory, design, components, optical systems, and frequency range are presented in approximately 96 citations. Abstracts on lasing dyes, pumping, tuning, excitation, molecular structure, and modulation are included. Studies on dye laser use in spectroscopy are covered.

  11. Continuous system modeling

    NASA Technical Reports Server (NTRS)

    Cellier, Francois E.

    1991-01-01

    A comprehensive and systematic introduction is presented for the concepts associated with 'modeling', involving the transition from a physical system down to an abstract description of that system in the form of a set of differential and/or difference equations, and basing its treatment of modeling on the mathematics of dynamical systems. Attention is given to the principles of passive electrical circuit modeling, planar mechanical systems modeling, hierarchical modular modeling of continuous systems, and bond-graph modeling. Also discussed are modeling in equilibrium thermodynamics, population dynamics, and system dynamics, inductive reasoning, artificial neural networks, and automated model synthesis.

  12. Encapsulation of thiazolyazoresorcinol and thiazolyazocresol dyes with α- and β-cyclodextrin cavities: Spectral and molecular modeling studies

    NASA Astrophysics Data System (ADS)

    Rajendiran, N.; Venkatesh, G.; Sankaranarayanan, R. K.

    2014-08-01

    Encapsulation behavior of 4-(2-thiazolyazo)resorcinol (TAR) and 2-(2-thiazolyazo)-p-cresol (TAC) with two cyclodextrins (α-CD and β-CD) were analyzed by UV-visible, fluorescence, time resolved fluorescence, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), proton nuclear magnetic resonance (1H NMR) and molecular modeling methods. With an increase in the CD concentrations, no considerable absorbance difference was observed in TAR and TAC but the fluorescence intensity increased. Compared to water solution, both azo dyes show longer life time in CD solutions. In non-polar solvent, the absorption wavelength observed at 440 nm suggests intramolecular hydrogen bonding (IHB) present between the sbnd OH⋯Ndbnd Nsbnd groups. The chemical shift values suggest that thiazole ring of the dye is included in the CD cavities and the phenol ring present to edge of the CD cavities. In TAC, SEM image revealed the presence of irregular shape crystals agglomerated rod with CD. Binding energy, ΔH and ΔG values indicate that both azo dyes form stable inclusion complex.

  13. Photocatalytic decolorization of soluble dyes by a bis-ions coexistence system of NH4(+) and NO3(-) with high photoreduction ability.

    PubMed

    Shifu, Chen; Wei, Liu; Huaye, Zhang; Xiaoling, Yu

    2011-02-28

    In this paper, we found that the acidic and basic dyes were easily decolorized by a bis-ions coexistence system of NH(4)(+) and NO(3)(-) under UV light irradiation. The coexistence of NH(4)(+) and NO(3)(-) is a necessary condition for the photocatalytic decolorization of soluble dyes. The photocatalytic decolorization of methyl orange (MO) and methylene blue (MB) follows the first order rate kinetics. The location of an absorption peak in the visible region is blue-shifted with the increase in the illumination time. It is proposed that the photocatalytic decolorization of soluble dyes in the bis-ions coexistence system of NH(4)(+) and NO(3)(-) is a photoreduction reaction, in which the ammonium nitrate acts as a photocatalyst. The chromophore of acidic and basic dyes reacts with hydrogen and then results in their rapid decolorization.

  14. [Vision engineering--photoelectric dye-based retinal prostheses: Okayama University model].

    PubMed

    Matsuo, Toshihiko

    2007-04-01

    Patients with retinitis pigmentosa lose photoreceptor cells by genetic abnormalities and hence become blind. Neurons such as bipolar cells and ganglion cells still remain alive even in the retina of these patients, and ganglion cells send axons to the brain as the optic nerve. The replacement of dead photoreceptor cells with something artificial is the basic concept of retinal prostheses. The remaining retinal neurons can be stimulated by either electric current or electric potential. Photodiode array and electrode array are two main ways to stimulate retinal neurons as retinal prostheses. These retinal prostheses have problems such as low sensitivity and requiring outer electric sources (batteries). To overcome the problems, we are developing photoelectric dye-based retinal prostheses which absorb light and convert photon energy to electric potentials. The prototype, photoelectric dye-coupled polyethylene film, could generate intracellular calcium elevation in photoreceptor-lacking retinal tissues and also in cultured retinal neurons. The photoelectric dye-based retinal prostheses are thin and soft, and therefore, a sheet of the film in a large size, corresponding to wide visual field, can be inserted into the vitreous and then to the subretinal space through a small opening by rolling up the film. After the production control and the quality control have been established, clinical trials of the photoelectric dye-based retinal prostheses would be planned in concordance with the Drugs and Medical Devices Law to prove the safety and the efficacy.

  15. Modeling recombination processes and predicting energy conversion efficiency of dye sensitized solar cells from first principles

    NASA Astrophysics Data System (ADS)

    Ma, Wei; Meng, Sheng

    2014-03-01

    We present a set of algorithms based on solo first principles calculations, to accurately calculate key properties of a DSC device including sunlight harvest, electron injection, electron-hole recombination, and open circuit voltages. Two series of D- π-A dyes are adopted as sample dyes. The short circuit current can be predicted by calculating the dyes' photo absorption, and the electron injection and recombination lifetime using real-time time-dependent density functional theory (TDDFT) simulations. Open circuit voltage can be reproduced by calculating energy difference between the quasi-Fermi level of electrons in the semiconductor and the electrolyte redox potential, considering the influence of electron recombination. Based on timescales obtained from real time TDDFT dynamics for excited states, the estimated power conversion efficiency of DSC fits nicely with the experiment, with deviation below 1-2%. Light harvesting efficiency, incident photon-to-electron conversion efficiency and the current-voltage characteristics can also be well reproduced. The predicted efficiency can serve as either an ideal limit for optimizing photovoltaic performance of a given dye, or a virtual device that closely mimicking the performance of a real device under different experimental settings.

  16. Using dyes for evaluating photocatalytic properties: a critical review.

    PubMed

    Rochkind, Malka; Pasternak, Sagi; Paz, Yaron

    2014-12-23

    This brief review aims at analyzing the use of dyestuffs for evaluating the photocatalytic properties of novel photocatalysts. It is shown that the use of dyes as predictors for photocatalytic activity has its roots in the pre visible-light activity era, when the aim was to treat effluents streams containing hazardous dyes. The main conclusion of this review is that, in general, dyes are inappropriate as model compounds for the evaluation of photocatalytic activity of novel photocatalysts claimed to operate under visible light. Their main advantage, the ability to use UV-Vis spectroscopy, is severely limited by a variety of factors, most of which are related to the presence of other species. The presence of a second mechanism, sensitization, diminishes the generality required from a model contaminant used for testing a novel photocatalyst. While it is recommended not to use dyes for general testing of novel photocatalysts, it is still understandable that a model system consisting of a dye and a semiconductor can be of large importance if the degradation of a specific dye is the main aim of the research, or, alternatively, if the abilities of a specific dye to induce the degradation of a different type of contaminant are under study.

  17. Specific tumor labeling enhanced by polyethylene glycol linkage of near infrared dyes conjugated to a chimeric anti-carcinoembryonic antigen antibody in a nude mouse model of human pancreatic cancer

    NASA Astrophysics Data System (ADS)

    Maawy, Ali A.; Hiroshima, Yukihiko; Zhang, Yong; Luiken, George A.; Hoffman, Robert M.; Bouvet, Michael

    2014-10-01

    Labeling of metastatic tumors can aid in their staging and resection of cancer. Near infrared (NIR) dyes have been used in the clinic for tumor labeling. However, there can be a nonspecific uptake of dye by the liver, lungs, and lymph nodes, which hinders detection of metastasis. In order to overcome these problems, we have used two NIR dyes (DyLight 650 and 750) conjugated to a chimeric anti-carcinoembryonic antigen antibody to evaluate how polyethylene glycol linkage (PEGylation) can improve specific tumor labeling in a nude mouse model of human pancreatic cancer. The conjugated PEGylated and non-PEGylated DyLight 650 and 750 dyes were injected intravenously into non-tumor-bearing nude mice. Serum samples were collected at various time points in order to determine serum concentrations and elimination kinetics. Conjugated PEGylated dyes had significantly higher serum dye concentrations than non-PEGylated dyes (p=0.005 for the 650 dyes and p<0.001 for the 750 dyes). Human pancreatic tumors subcutaneously implanted into nude mice were labeled with antibody-dye conjugates and serially imaged. Labeling with conjugated PEGylated dyes resulted in significantly brighter tumors compared to the non-PEGylated dyes (p<0.001 for the 650 dyes; p=0.01 for 750 dyes). PEGylation of the NIR dyes also decreased their accumulation in lymph nodes, liver, and lung. These results demonstrate enhanced selective tumor labeling by PEGylation of dyes conjugated to a tumor-specific antibody, suggesting their future clinical use in fluorescence-guided surgery.

  18. Statistical optimization and artificial neural network modeling for acridine orange dye degradation using in-situ synthesized polymer capped ZnO nanoparticles.

    PubMed

    Dhiman, Nitesh; Markandeya; Singh, Amrita; Verma, Neeraj K; Ajaria, Nidhi; Patnaik, Satyakam

    2017-05-01

    ZnO NPs were synthesized by a prudent green chemistry approach in presence of polyacrylamide grafted guar gum polymer (pAAm-g-GG) to ensure uniform morphology, and functionality and appraised for their ability to degrade photocatalytically Acridine Orange (AO) dye. These ZnO@pAAm-g-GG NPs were thoroughly characterized by various spectroscopic, XRD and electron microscopic techniques. The relative quantity of ZnO NPs in polymeric matrix has been estimated by spectro-analytical procedure; AAS and TGA analysis. The impact of process parameters viz. NP's dose, contact time and AO dye concentration on percentage photocatalytic degradation of AO dyes were evaluated using multivariate optimizing tools, Response Surface Methodology (RSM) involving Box-Behnken Design (BBD) and Artificial Neural Network (ANN). Congruity of the BBD statistical model was implied by R(2) value 0.9786 and F-value 35.48. At RSM predicted optimal condition viz. ZnO@pAAm-g-GG NP's dose of 0.2g/L, contact time of 210min and AO dye concentration 10mg/L, a maximum of 98% dye degradation was obtained. ANOVA indicated appropriateness of the model for dye degradation owing to "Prob.>F" less than 0.05 for variable parameters. We further, employed three layers feed forward ANN model for validating the BBD process parameters and suitability of our chosen model. The evaluation of Levenberg-Marquardt algorithm (ANN1) and Gradient Descent with adaptive learning rate (ANN2) model employed to scrutinize the best method and found experimental values of AO dye degradation were in close to those with predicated value of ANN 2 modeling with minimum error.

  19. Binding of fluorescent acridine dyes acridine orange and 9-aminoacridine to hemoglobin: Elucidation of their molecular recognition by spectroscopy, calorimetry and molecular modeling techniques.

    PubMed

    Chatterjee, Sabyasachi; Kumar, Gopinatha Suresh

    2016-06-01

    The molecular interaction between hemoglobin (HHb), the major human heme protein, and the acridine dyes acridine orange (AO) and 9-aminoacridine (9AA) was studied by various spectroscopic, calorimetric and molecular modeling techniques. The dyes formed stable ground state complex with HHb as revealed from spectroscopic data. Temperature dependent fluorescence data showed the strength of the dye-protein complexation to be inversely proportional to temperature and the fluorescence quenching was static in nature. The binding-induced conformational change in the protein was investigated using circular dichroism, synchronous fluorescence, 3D fluorescence and FTIR spectroscopy results. Circular dichroism data also quantified the α-helicity change in hemoglobin due to the binding of acridine dyes. Calorimetric studies revealed the binding to be endothermic in nature for both AO and 9AA, though the latter had higher affinity, and this was also observed from spectroscopic data. The binding of both dyes was entropy driven. pH dependent fluorescence studies revealed the existence of electrostatic interaction between the protein and dye molecules. Molecular modeling studies specified the binding site and the non-covalent interactions involved in the association. Overall, the results revealed that a small change in the acridine chromophore leads to remarkable alteration in the structural and thermodynamic aspects of binding to HHb.

  20. Improved azo dye decolorization in an advanced integrated system of bioelectrochemical module with surrounding electrode deployment and anaerobic sludge reactor.

    PubMed

    Kong, Fanying; Wang, Aijie; Ren, Hong-Yu

    2015-01-01

    A new integrated system, embedding a modular bioelectrochemical system (BES) with surrounding electrode deployment into an anaerobic sludge reactor (ASR), was developed to improve azo dye decolorization. Results demonstrated that the AO7 decolorization and COD removal can be improved without co-substrate in such system. The kinetic rate of decolorization (0.54h(-1)) in integrated system was 1.4-fold and 54.0-fold higher than that in biocathode BES (0.39h(-1)) and ASR (0.01h(-1)), respectively. COD can be removed after cleavage of azo bond, different from biocathode BES. The combined advantages of this integrated system were achieved by the cooperation of biocathode in modular BES and sludge in ASR. Biocathode was a predominant factor in AO7 decolorization, and anaerobic sludge contributed negligibly to AO7 reduction decolorization but mostly in the COD removal. These results demonstrated the great potential of integrating a BES module with anaerobic treatment process for azo dye treatment.

  1. Developmental Validation of a novel 5 dye Y-STR System comprising the 27 YfilerPlus loci

    PubMed Central

    Bai, Rufeng; Liu, Yaju; Li, Zheng; Jin, Haiying; Tian, Qinghua; Shi, Meisen; Ma, Shuhua

    2016-01-01

    In this study, a new STRtyper-27 system, including the same Yfiler Plus loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385a/b, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, Y-GATA H4, DYS449, DYS460, DYS481, DYS518, DYS533, DYS570, DYS576, DYS627 and DYF387S1a/b), was established using a set of 5 fluorescent dye labels. Primers, internal size standard, allelic ladders and matrix standard set were designed and created in-house for this multiplex system. This paper describes the validation studies conducted with the STRtyper-27Y system using a 3130XL genetic analyzer for fragment length detection that included the analysis of the following parameters and aspects: sensitivity, species specificity, inhibition, haplotype concordance, precision, stutter, DNA mixtures, and stability studies with crime scene samples. The studies demonstrated, that the STRtyper-27Y system provided equivalent overall performance comparable to the latest Yfiler Plus kit, but with enhanced compatibility in terms of instrument platforms and software allowing forensic laboratories to conduct its forensic application and evaluate its performance, all in their own 5 dye Y-STR chemistry system /environment without software or instrument upgrades. PMID:27406339

  2. Developmental Validation of a novel 5 dye Y-STR System comprising the 27 YfilerPlus loci.

    PubMed

    Bai, Rufeng; Liu, Yaju; Li, Zheng; Jin, Haiying; Tian, Qinghua; Shi, Meisen; Ma, Shuhua

    2016-07-13

    In this study, a new STRtyper-27 system, including the same Yfiler Plus loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385a/b, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, Y-GATA H4, DYS449, DYS460, DYS481, DYS518, DYS533, DYS570, DYS576, DYS627 and DYF387S1a/b), was established using a set of 5 fluorescent dye labels. Primers, internal size standard, allelic ladders and matrix standard set were designed and created in-house for this multiplex system. This paper describes the validation studies conducted with the STRtyper-27Y system using a 3130XL genetic analyzer for fragment length detection that included the analysis of the following parameters and aspects: sensitivity, species specificity, inhibition, haplotype concordance, precision, stutter, DNA mixtures, and stability studies with crime scene samples. The studies demonstrated, that the STRtyper-27Y system provided equivalent overall performance comparable to the latest Yfiler Plus kit, but with enhanced compatibility in terms of instrument platforms and software allowing forensic laboratories to conduct its forensic application and evaluate its performance, all in their own 5 dye Y-STR chemistry system /environment without software or instrument upgrades.

  3. Complete degradation of the azo dye Acid Orange-7 and bioelectricity generation in an integrated microbial fuel cell, aerobic two-stage bioreactor system in continuous flow mode at ambient temperature.

    PubMed

    Fernando, Eustace; Keshavarz, Taj; Kyazze, Godfrey

    2014-03-01

    In this study, the commercially used model azo dye Acid Orange-7 (AO-7) was fully degraded into less toxic intermediates using an integrated microbial fuel cell (MFC) and aerobic bioreactor system. The integrated bioreactor system was operated at ambient temperature and continuous-flow mode. AO-7 loading rate was varied during experiments from 70gm(-3)day(-1) to 210gm(-3)day(-1). Colour and soluble COD removal rates reached>90% under all AO-7 loading rates. The MFC treatment stage prompted AO-7 to undergo reductive degradation into its constituent aromatic amines. HPLC-MS analysis of metabolite extracts from the aerobic stage of the bioreactor system indicated further oxidative degradation of the resulting aromatic amines into simpler compounds. Bioluminescence based Vibrio fischeri ecotoxicity testing demonstrated that aerobic stage effluent exhibited toxicity reductions of approximately fivefold and ten-fold respectively compared to the dye wastewater influent and MFC-stage effluent.

  4. Discovery of Black Dye Crystal Structure Polymorphs: Implications for Dye Conformational Variation in Dye-Sensitized Solar Cells.

    PubMed

    Cole, Jacqueline M; Low, Kian Sing; Gong, Yun

    2015-12-23

    We present the discovery of a new crystal structure polymorph (1) and pseudopolymorph (2) of the Black Dye, one of the world's leading dyes for dye-sensitized solar cells, DSSCs (10.4% device performance efficiency). This reveals that Black Dye molecules can adopt multiple low-energy conformers. This is significant since it challenges existing models of the Black Dye···TiO2 adsorption process that renders a DSSC working electrode; these have assumed a single molecular conformation that refers to the previously reported Black Dye crystal structure (3). The marked structural differences observed between 1, 2, and 3 make the need for modeling multiple conformations more acute. Additionally, the ordered form of the Black Dye (1) provides a more appropriate depiction of its anionic structure, especially regarding its anchoring group and NCS bonding descriptions. The tendency toward NCS ligand isomerism, evidenced via the disordered form 2, has consequences for electron injection and electron recombination in Black Dye embedded DSSC devices. Dyes 2 and 3 differ primarily by the absence or presence of a solvent of crystallization, respectively; solvent environment effects on the dye are thereby elucidated. This discovery of multiple Black Dye conformers from diffraction, with atomic-level definition, complements recently reported nanoscopic evidence for multiple dye conformations existing at a dye···TiO2 interface, for a chemically similar DSSC dye; those results emanated from imaging and spectroscopy, but were unresolved at the submolecular level. Taken together, these findings lead to the general notion that multiple dye conformations should be explicitly considered when modeling dye···TiO2 interfaces in DSSCs, at least for ruthenium-based dye complexes.

  5. Dye Painting with Fiber Reactive Dyes

    ERIC Educational Resources Information Center

    Benjamin-Murray, Betsy

    1977-01-01

    In her description of how to use dyes directly onto fabrics the author lists materials to be used, directions for mixing dyes, techniques for applying dyes, references for additional reading and sources for dye materials. Preceding the activity with several lessons in design and other textile techniques with the dye process will ensure a…

  6. Structure-based modeling of dye-fiber affinity with SOM-4D-QSAR paradigm: application to set of anthraquinone derivatives.

    PubMed

    Bak, Andrzej; Wyszomirski, Miroslaw; Magdziarz, Tomasz; Smolinski, Adam; Polanski, Jaroslaw

    2014-01-01

    A comparative structure-affinity study of anthraquinone dyes adsorption on cellulose fibre is presented in this paper. We used receptor-dependent 4D-QSAR methods based on grid and neural (SOM) methodology coupled with IVEPLS procedure. The applied RD 4D-QSAR approach focuses mainly on the ability of mapping dye properties to verify the concept of tinctophore in dye chemistry. Moreover, the stochastic SMV procedure to investigate the predictive ability of the method for a large population of 4D-QSAR models was employed. The obtained findings were compared with the previously published RI 3D/4D-QSAR models for the corresponding anthraquinone trainings sets. The neutral (protonated) and anionic (deprotonated) forms of anthraquinone scaffold were examined in order to deal with the uncertainty of the dye ionization state. The results are comparable to both the neutral and anionic dye sets regardless of the occupancy and charge descriptors applied, respectively. It is worth noting that the SOM-4D-QSAR behaves comparably to the cubic counterpart which is observed in each training/test subset specification (4D-QSAR-Jo vs SOM- 4D-QSARo and 4D-QSAR-Jq vs SOM-4D-QSARq). Additionally, an attempt was made to specify a common set of variables contributing significantly to dye-fiber binding affinity; it was simultaneously performed for some arbitrary chosen SMV models. The presented RD 4D-QSAR methodology together with IVE-PLS procedure provides a robust and predictive modeling technique, which facilitates detailed specification of the molecular motifs significantly contributing to the fiber-dye affinity.

  7. The mathematical model of dye diffusion and adsorption on modified cellulose with triazine derivatives containing cationic and anionic groups

    NASA Astrophysics Data System (ADS)

    Xie, K.; Hou, A.; Chen, Y.

    2008-02-01

    Cellulose fabric is chemically modified with the compounds containing cationic and anionic groups. The molecular chains of modified cellulose have both cationic and anionic groups. Dye diffusion properties on modified cellulose are discussed. The dye adsorption and diffusion on modified cellulose are higher than those on unmodified cellulose. The diffusion properties of dyes at different temperature are discussed. Compared with unmodified cellulose, the diffusion processing of dyes in the modified cotton cellulose shows significant change.

  8. Interaction of BODIPY Dyes with the Blood Plasma Proteins.

    PubMed

    Marfin, Yu S; Aleksakhina, E L; Merkushev, D A; Rumyantsev, E V; Tomilova, I K

    2016-01-01

    Photophysical properties of several BODIPY-based fluorescent dyes were investigated in systems containing blood plasma biomolecules and in model system containing bovine serum albumin in terms of electronic absorption and fluorescence spectroscopy. The interaction between the investigated dyes and protein plasma components changes spectral characteristics of the dyes and leads to bathochromic and hypochromic absorption spectra shifts accompanied by changing of fluorescence intensity. The mechanism of fluorescence changing was defined in the terms of Stern-Volmer theory. It was shown that the static factor of molecular dye-biopolymers complex formation prevails at plasma protein concentration up to 1 g/l, while the higher viscosity range is characterized mainly by nonspecific fluorophore interactions. The increase of fluorescent characteristics of phenyl-substituted BODIPY in the presence of proteins caused by resonance energy transfer and change of physicochemical properties of the molecular environment of the fluorophore was shown for the first time.

  9. Mathematical circulatory system model

    NASA Technical Reports Server (NTRS)

    Lakin, William D. (Inventor); Stevens, Scott A. (Inventor)

    2010-01-01

    A system and method of modeling a circulatory system including a regulatory mechanism parameter. In one embodiment, a regulatory mechanism parameter in a lumped parameter model is represented as a logistic function. In another embodiment, the circulatory system model includes a compliant vessel, the model having a parameter representing a change in pressure due to contraction of smooth muscles of a wall of the vessel.

  10. Application of linear and non-linear methods for modeling removal efficiency of textile dyes from aqueous solutions using magnetic Fe3O4 impregnated onto walnut shell

    NASA Astrophysics Data System (ADS)

    Ashrafi, Motahare; Arab Chamjangali, Mansour; Bagherian, Ghadamali; Goudarzi, Nasser

    2017-01-01

    The performance of the Nano-magnetite Fe3O4 impregnated onto walnut shell (Fe3O4-WNS), which possessed the adsorption features of walnut shell and the magnetic property of Fe3O4, was investigated for the elimination of the methyl violet and Rhodamine 6G from contaminated aqueous solutions. The effects of different experimental variables on the removal efficiency of the cited dyes were examined. Then these variables were used as the inputs to generate linear and non-linear models such as the multiple linear regression, random forest, and artificial neural network to predict the removal efficiency of these dye species at different experimental conditions. The validation studies of these models were performed using the test set, which was not present in the modeling procedure. It was found that ANN had a higher ability to predict the adsorption process under different experimental conditions, and could be applied for the development of an automated dye wastewater removal plant. Also the maximum adsorption capacity (qmax) indicated that the qmax value for Fe3O4-WNS for removal of cationic dyes was comparable or better than that for some reported adsorbents. Also it should be cited that exhausted Fe3O4-WNS was regenerated using dishwashing liquid, and reused for removal of the cited dye species from aqueous solutions.

  11. Application of linear and non-linear methods for modeling removal efficiency of textile dyes from aqueous solutions using magnetic Fe3O4 impregnated onto walnut shell.

    PubMed

    Ashrafi, Motahare; Arab Chamjangali, Mansour; Bagherian, Ghadamali; Goudarzi, Nasser

    2017-01-15

    The performance of the Nano-magnetite Fe3O4 impregnated onto walnut shell (Fe3O4-WNS), which possessed the adsorption features of walnut shell and the magnetic property of Fe3O4, was investigated for the elimination of the methyl violet and Rhodamine 6G from contaminated aqueous solutions. The effects of different experimental variables on the removal efficiency of the cited dyes were examined. Then these variables were used as the inputs to generate linear and non-linear models such as the multiple linear regression, random forest, and artificial neural network to predict the removal efficiency of these dye species at different experimental conditions. The validation studies of these models were performed using the test set, which was not present in the modeling procedure. It was found that ANN had a higher ability to predict the adsorption process under different experimental conditions, and could be applied for the development of an automated dye wastewater removal plant. Also the maximum adsorption capacity (qmax) indicated that the qmax value for Fe3O4-WNS for removal of cationic dyes was comparable or better than that for some reported adsorbents. Also it should be cited that exhausted Fe3O4-WNS was regenerated using dishwashing liquid, and reused for removal of the cited dye species from aqueous solutions.

  12. Use of the ultrasonic cavitation in wool dyeing process: Effect of the dye-bath temperature.

    PubMed

    Actis Grande, G; Giansetti, M; Pezzin, A; Rovero, G; Sicardi, S

    2017-03-01

    The present work aims to study the effect of the liquid temperature on the performance of ultrasounds (US) in a dyeing process. The approach was both theoretical and experimental. In the theoretical part the simplified model of a single bubble implosion is used to demonstrate that the "maximum implosion pressure" calculated with the well known Rayleigh-Plesset equation for a single bubble can be correlated with the cavitation intensity experimentally measured with an Ultrasonic Energy Meter (by PPB Megasonics). In particular the model was used to study the influence of the fluid temperature on the cavitation intensity. The "relative" theoretical data calculated from the implosion pressure were satisfactorily correlated with the experimental ones and evidence a zone, between 50 and 60°C, were the cavitation intensity is almost constant and still sufficiently high. Hence an experimental part of wool dyeing was carried out both to validate the previous results and to verify the dyeing quality at low temperatures (40-70°C) in presence of US. A prototype dyeing equipment able to treat textile samples with US system of 600W power, was used. The dyeing performances in the presence and absence of US were verified by measuring ΔE (colour variation), Re,% (reflectance percentage), K/S (colour strength) and colour fastness. The US tests performed in the temperature range of 40-70°C were compared with the conventional wool dyeing at 98°C. The obtained results show that a temperature close to 60°C should be chosen as the recommended US dyeing condition, being a compromise between the cavitation intensity and the kinetics which rules the dyestuff diffusion within the fibres.

  13. Synthesis, spectral characterization, molecular modeling and antimicrobial studies of tridentate azo-dye Schiff base metal complexes

    NASA Astrophysics Data System (ADS)

    Alaghaz, Abdel-Nasser M. A.; Zayed, Mohamed E.; Alharbi, Suliman A.

    2015-03-01

    Nine mononuclear Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pt(IV) complexes of azo-dye Schiff's base ligand were synthesized and determined by different physical techniques. All the nine metal complexes are reported using elemental analysis, molar conductance, magnetic susceptibility, IR, UV-Vis, thermal analysis and 1H NMR, 13C NMR, mass, SEM, TEM, EDX, XRD spectral studies. The molar conductance measurements of all the complexes in DMF solution correspond to non-electrolytic nature. All complexes were of the high-spin type and found to have six-coordinate octahedral geometry except the Cu(II) complex which was four coordinate, square planar. Quantum chemical calculations were performed with semi-empirical method to find the optimum geometry of the ligand and its complexes. In molecular modeling the geometries of azo-dye Schiff base ligand HL and its metal (II/III/IV) complexes were fully optimized with respect to the energy using the 6-31G basis set. These ligand and its metal complexes have also been screened for their in vitro antimicrobial activities.

  14. Degradation of a model azo dye in submerged anaerobic membrane bioreactor (SAMBR) operated with powdered activated carbon (PAC).

    PubMed

    Baêta, B E L; Luna, H J; Sanson, A L; Silva, S Q; Aquino, S F

    2013-10-15

    This work investigated the anaerobic degradation of the model azo dye Remazol Yellow Gold RNL in an upflow anaerobic sludge blanket reactor (UASB) and two submerged anaerobic membrane (SAMBR) bioreactors, one of which (SAMBR-1) was operated with powdered activated carbon (PAC) in its interior. The reactors were operated at 35 °C with a hydraulic retention time of 24 h in three operational phases, aimed to assess the effect of external sources of carbon (glucose) or redox mediator (yeast extract) on the removal or color and organic matter. The results showed that removal efficiencies of COD (73-94%) and color (90-94%) were higher for SAMBR-1 when compared to SAMBR-2 (operated without PAC) and UASB reactors. In addition, the presence of PAC in SAMBR-1 increased reactor stability, thereby leading to a lower accumulation of volatile fatty acids (VFA). The microfiltration membrane was responsible for an additional removal of ~50% of soluble residual COD in the form of VFA, thus improving permeate quality. On its turn, PAC exhibited the ability to adsorb byproducts (aromatic amines) of azo dye degradation as well as to act as source of immobilized redox mediator (quinone groups on its surface), thereby enhancing color removal.

  15. Mathematical modelling and optimization of synthetic textile dye removal using soil composites as highly competent liner material.

    PubMed

    Das, Papita; Banerjee, Priya; Mondal, Sandip

    2015-01-01

    Soil is widely used as adsorbent for removing toxic pollutants from their aqueous solutions due to its wide availability and cost efficiency. This study investigates the potential of soil and soil composites for removal of crystal violet (CV) dye from solution on a comparative scale. Optimisation of different process parameters was carried out using a novel approach of response surface methodology (RSM) and a central composite design (CCD) was used for determining the optimum experimental conditions, as well as the result of their interactions. Around 99.85 % removal of CV was obtained at initial pH 6.4, which further increased to 99.98 % on using soil and cement composite proving it to be the best admixture of those selected. The phenomenon was found to be represented best by the Langmuir isotherm at different temperatures. The process followed the pseudo-second-order kinetic model and was determined to be spontaneous chemisorption in nature. This adsorbent can hence be suggested as an appropriate liner material for the removal of CV dye.

  16. Synthesis, Characterization, Molecular Modeling, and DNA Interaction Studies of Copper Complex Containing Food Additive Carmoisine Dye.

    PubMed

    Shahabadi, Nahid; Akbari, Alireza; Jamshidbeigi, Mina; Khodarahmi, Reza

    2016-06-02

    A copper complex of carmoisine dye; [Cu(carmoisine)2(H2O)2]; was synthesized and characterized by using physico-chemical and spectroscopic methods. The binding of this complex with calf thymus (ct) DNA was investigated by circular dichroism, absorption studies, emission spectroscopy, and viscosity measurements. UV-vis results confirmed that the Cu complex interacted with DNA to form a ground-state complex and the observed binding constant (2× 10(4) M(-1)) is more in keeping with the groove bindings with DNA. Furthermore, the viscosity measurement result showed that the addition of complex causes no significant change on DNA viscosity and it indicated that the intercalation mode is ruled out. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the reaction. The results of circular dichroism (CD) suggested that the complex can change the conformation of DNA from B-like form toward A-like conformation. The cytotoxicity studies of the carmoisine dye and its copper complex indicated that both of them had anticancer effects on HT-29 (colon cancer) cell line and they may be new candidates for treatment of the colon cancer.

  17. The incorporation of dyes into hair as a model for drug binding.

    PubMed

    DeLauder, S F; Kidwell, D A

    2000-01-10

    The binding of charged substances from external aqueous media to hair has been investigated through the use of fluorescence microscopy. Eleven hair samples, reflecting various ethnic groups and cosmetic treatments, were tested. Rhodamine 6G, a cationic dye representative of drugs such as cocaine and opiates, showed incorporation throughout the hair of all samples except one. In contrast, fluorescein, an anionic dye representative of drugs such as THC carboxylic acid, was not readily incorporated. The incorporation of rhodamine 6G was faster for chemically 'straightened' and bleached African-American female hair than for untreated hair. Incorporation of rhodamine 6G followed a pH dependence, but an ionic strength dependence could not be established. These studies support three postulates: (1) electrostatic interactions explain the preferential binding of cationic drugs of abuse to hair; (2) the hair matrix, or the non-helical portion of hair, is accessible to external solutions and thus subject to contamination; and (3) cosmetic treatments may alter the helical portion of hair thereby increasing its accessibility to external contamination.

  18. Dyeing Industry Effluent System as Lipid Production Medium of Neochloris sp. for Biodiesel Feedstock Preparation

    PubMed Central

    Ramamurthy, Dhandapani

    2014-01-01

    Microalgae lipid feedstock preparation cost was an important factor in increasing biodiesel fuel hikes. This study was conducted with the concept of implementing an effluent wastewater as lipid production medium for microalgae cultivation. In our study textile dyeing industry effluent was taken as a lipid production medium for Neochloris sp. cultivation. The changes in physicochemical analysis of effluent before and after Neochloris sp. treatment were recorded using standard procedures and AAS analysis. There was especially a reduction in heavy metal like lead (Pb) concentration from 0.002 ppm to 0.001 ppm after Neochloris sp. treatment. Neochloris sp. cultivated in Bold Basal Medium (BBM) (specific algal medium) produced 41.93% total lipid and 36.69% lipid was produced in effluent based cultivation. Surprisingly Neochloris sp. cultivated in effluent was found with enhanced neutral lipid content, and it was confirmed by Nile red fluorescence assay. Further the particular enrichment in oleic acid content of the cells was confirmed with thin layer chromatography (TLC) with oleic acid pure (98%) control. The overall results suggested that textile dyeing industry effluent could serve as the best lipid productive medium for Neochloris sp. biodiesel feedstock preparation. This study was found to have a significant impact on reducing the biodiesel feedstock preparation cost with simultaneous lipid induction by heavy metal stress to microalgae. PMID:25247176

  19. Characteristics of a Broadband Dye Laser Using Pyrromethene and Rhodamine Dyes

    NASA Technical Reports Server (NTRS)

    Tedder, Sarah A.; Danehy, Paul M.; Wheeler, Jeffrey L.

    2011-01-01

    A broadband dye laser pumped by a frequency-doubled Nd:YAG laser with a full-width half-maximum (FWHM) from 592 to 610 nm was created for the use in a dual-pump broadband CARS system called WIDECARS. The desired broadband dye laser was generated with a mixture of Pyrromethene dyes as an oscillator gain medium and a spectral selective optic in the oscillator cavity. A mixture of Rhodamine dyes were used in the amplifier dye cell. To create this laser a study was performed to characterize the spectral behavior of broadband dye lasers created with Rhodamine dyes 590, 610, and 640, Pyrromethene dyes 597 and 650 as well as mixture of these dyes.

  20. Efficient azo dye decolorization in a continuous stirred tank reactor (CSTR) with built-in bioelectrochemical system.

    PubMed

    Cui, Min-Hua; Cui, Dan; Gao, Lei; Cheng, Hao-Yi; Wang, Ai-Jie

    2016-10-01

    A continuous stirred tank reactor with built-in bioelectrochemical system (CSTR-BES) was developed for azo dye Alizarin Yellow R (AYR) containing wastewater treatment. The decolorization efficiency (DE) of the CSTR-BES was 97.04±0.06% for 7h with sludge concentration of 3000mg/L and initial AYR concentration of 100mg/L, which was superior to that of the sole CSTR mode (open circuit: 54.87±4.34%) and the sole BES mode (without sludge addition: 91.37±0.44%). The effects of sludge concentration and sodium acetate (NaAc) concentration on azo dye decolorization were investigated. The highest DE of CSTR-BES for 4h was 87.66±2.93% with sludge concentration of 12,000mg/L, NaAc concentration of 2000mg/L and initial AYR concentration of 100mg/L. The results in this study indicated that CSTR-BES could be a practical strategy for upgrading conventional anaerobic facilities against refractory wastewater treatment.

  1. Optimization studies of bio-hydrogen production in a coupled microbial electrolysis-dye sensitized solar cell system.

    PubMed

    Ajayi, Folusho Francis; Kim, Kyoung-Yeol; Chae, Kyu-Jung; Choi, Mi-Jin; Chang, In Seop; Kim, In S

    2010-03-01

    Bio-hydrogen production in light-assisted microbial electrolysis cell (MEC) with a dye sensitized solar cell (DSSC) was optimized by connecting multiple MECs to a single dye (N719) sensitized solar cell (V(OC) approx. 0.7 V). Hydrogen production occurred simultaneously in all the connected MECs when the solar cell was irradiated with light. The amount of hydrogen produced in each MEC depends on the activity of the microbial catalyst on their anode. Substrate (acetate) to hydrogen conversion efficiencies ranging from 42% to 65% were obtained from the reactors during the experiment. A moderate light intensity of 430 W m(-2) was sufficient for hydrogen production in the coupled MEC-DSSC. A higher light intensity of 915 W m(-2), as well as an increase in substrate concentration, did not show any improvement in the current density due to limitation caused by the rate of microbial oxidation on the anode. A significant reduction in the surface area of the connected DSSC only showed a slight effect on current density in the coupled MEC-DSSC system when irradiated with light.

  2. Current distribution evaluation of dye-sensitized solar cell using HTS-SQUID-based magnetic measurement system

    NASA Astrophysics Data System (ADS)

    Sakai, Kenji; Tanaka, Kohei; Kiwa, Toshihiko; Tsukada, Keiji

    2016-11-01

    The current flowing inside a dye-sensitized solar cell (DSSC) was measured using a high-temperature superconductor superconducting quantum interference device (HTS-SQUID)-based magnetic measurement system. Further, a new evaluation method of the DSSC, which is difficult to measure using the conventional method, was investigated to improve the characteristics of the DSSC. The tangential components of the magnetic field generated from the DSSC were measured using two HTS-SQUIDs, and the intensity and direction related to the electrical current were obtained by the measured magnetic field. The DSSCs prepared with different dyes and catalytic substances showed different current-intensity mapping. The current direction was different for the DSSC with low performance. In addition, the current flowing in the ITO layer of the ITO glass substrate was also measured and the results confirmed that it had uniform distribution. These results show that the current mapping and the direction of the electrical current depend on the internal factors of the DSSC, and the detection of the magnetic field distribution generated from it is expected to lead to its new evaluation method.

  3. Density functional theory study on dye-sensitized solar cells using oxadiazole-based dyes

    NASA Astrophysics Data System (ADS)

    Mehmood, Umer; Hussein, Ibnelwaleed A.; Harrabi, Khalil; Reddy, Belum V. S.

    2015-01-01

    Density functional theory (DFT) and time-dependent DFT(TD-DFT) modeling techniques are used to conduct a computational study of the geometry and electronic structure of oxadiazole-based organic sensitizers. A DFT study on the thermodynamic aspects of the charge transport processes associated with dye-sensitized solar cells (DSSCs) suggests that the system with 1,2,4-oxadiazole has a balance among the different crucial factors and may result in the highest incident photon to charge carrier efficiency. The dye/) anatase clusters were also simulated to illustrate the electron injection efficiency at the interface. This study provides basic understanding of the impact of molecular design on the performance of oxadiazole dyes in DSSCs.

  4. Influence of operational key parameters on the photocatalytic decolorization of Rhodamine B dye using Fe2+/H2O2/Nb2O5/UV system.

    PubMed

    Hashemzadeh, Fatemeh; Rahimi, Rahmatollah; Gaffarinejad, Ali

    2014-04-01

    The present research deals with the development of a new heterogeneous photocatalysis and Fenton hybrid system for the removal of color from textile dyeing wastewater as Rhodamine B (RhB) solutions by using Fe(2+)/H2O2/Nb2O5 as a photocatalytic system. The application of this photocatalytic system for the decolorization of dye contaminants is not reported in the literature yet. Different parameters like dye concentration, Nb2O5/Fe(2+) catalyst amount, pH, and H2O2 concentration have been studied. The optimum conditions for the decolorization of the dye were initial concentration of 10 mg L(-1) of dye, pH 4, and Nb2O5/Fe(2+) catalyst concentration of 0.5 g L(-1)/50 mg L(-1). The optimum value of H2O2 concentration for the conditions used in this study was 700 mg L(-1). Moreover, the efficiency of the Nb2O5/photo-Fenton hybrid process in comparison to photo-Fenton alone and a dark Fenton process as a control experiment to decolorize the RhB solution has been investigated. The combination of photo-Fenton and Nb2O5 catalysts has been proved to be the most effective for the treatment of such type of wastewaters. The results revealed that the RhB dye was decolorized in a higher percent (78 %) by the Nb2O5/photo-Fenton hybrid process (Fe(2+)/H2O2/Nb2O5/UV) than by the photo-Fenton process alone (37 %) and dark Fenton process (14 %) after 120 min of treatment. Moreover, the Nb2O5 catalyst as a heterogeneous part of the photocatalytic system was demonstrated to have good stability and reusability.

  5. Dye lasers: Design, operation, and performance. March 1975-October 1989 (Citations from the Searchable Physics Information Notices data base). Report for Mar 75-Oct 89

    SciTech Connect

    Not Available

    1989-11-01

    This bibliography contains citations concerning the design, operation, and performance of dye lasers. Dye materials, pulse techniques, laser pumping systems, experimental applications, design of dye laser systems, and performance evaluations are considered. Modeling of dye laser operation is also discussed. Descriptions of system components and experimental variables, and their effects on laser output are included. References to other laser systems such as carbon dioxide lasers, x-ray lasers, and UV lasers are included in related bibliographies. (Contains 264 citations fully indexed and including a title list.)

  6. Statistical thermodynamics of adsorption of dye DR75 onto natural materials and its modifications: double-layer model with two adsorption energies.

    PubMed

    Khalfaoui, M; Nakhli, A; Aguir, Ch; Omri, A; M'henni, M F; Ben Lamine, A

    2014-02-01

    In this article, adsorption modelling was presented to describe the sorption of textile dye, Direct Red 75 (DR75), from coloured wastewater onto the natural and modified adsorbent, Posidonia oceanica. The formulation of the double-layer model with two energy levels was based on statistical physics and theoretical considerations. Thanks to the grand canonical ensemble in statistical physics some physico-chemical parameters related to the adsorption process were introduced in the analytical model expression. Fitting results show that the dye molecules are adsorbed in parallel position to the adsorbent surface. The magnitudes of the calculated adsorption energies show that the DR75 dye is physisorbed onto Posidonia. Both Van der Waals and hydrogen interactions are implicated in the adsorption process. Despite its simplicity, the model fits a wide range of experimental data, thereby supporting the underlying data that the grafted groups facilitate the parallel anchorage of the anionic dye molecule. Thermodynamic parameters, such as adsorption energy, entropy, Gibbs free adsorption energy and internal energy were calculated according to the double-layer model. Results suggested that the DR75 adsorption onto Posidonia was a spontaneous and exothermic process.

  7. MLS: Airplane system modeling

    NASA Technical Reports Server (NTRS)

    Thompson, A. D.; Stapleton, B. P.; Walen, D. B.; Rieder, P. F.; Moss, D. G.

    1981-01-01

    Analysis, modeling, and simulations were conducted as part of a multiyear investigation of the more important airplane-system-related items of the microwave landing system (MLS). Particular emphasis was placed upon the airplane RF system, including the antenna radiation distribution, the cabling options from the antenna to the receiver, and the overall impact of the airborne system gains and losses upon the direct-path signal structure. In addition, effort was expended toward determining the impact of the MLS upon the airplane flight management system and developing the initial stages of a fast-time MLS automatic control system simulation model. Results ot these studies are presented.

  8. Physicochemical modeling of reactive violet 5 dye adsorption on home-made cocoa shell and commercial activated carbons using the statistical physics theory

    NASA Astrophysics Data System (ADS)

    Sellaoui, Lotfi; Lima, Éder Cláudio; Dotto, Guilherme Luiz; Dias, Silvio L. P.; Ben Lamine, Abdelmottaleb

    Two equilibrium models based on statistical physics, i.e., monolayer model with single energy and multilayer model with saturation, were developed and employed to access the steric and energetic aspects in the adsorption of reactive violet 5 dye (RV-5) on cocoa shell activated carbon (AC) and commercial activated carbon (CAC), at different temperatures (from 298 to 323 K). The results showed that the multilayer model with saturation was able to represent the adsorption system. This model assumes that the adsorption occurs by a formation of certain number of layers. The n values ranged from 1.10 to 2.98, indicating that the adsorbate molecules interacted in an inclined position on the adsorbent surface and aggregate in solution. The study of the total number of the formed layers (1 + L2) showed that the steric hindrance is the dominant factor. The description of the adsorbate-adsorbent interactions by calculation of the adsorption energy indicated that the process occurred by physisorption in nature, since the values were lower than 40 kJ mol-1.

  9. Identification of a quinone dehydrogenase from a Bacillus sp. involved in the decolourization of the lignin-model dye, Azure B.

    PubMed

    Bandounas, Luaine; Pinkse, Martijn; de Winde, Johannes H; Ruijssenaars, Harald J

    2013-01-25

    In this study we have investigated the molecular background of the previously reported dye decolourization potential of Bacillus sp. LD003. Strain LD003 was previously isolated on Kraft lignin and was able to decolourize various lignin model dyes. Specifically Azure B (AB) was decolourized efficiently. Proteins possibly involved in AB decolourization were partially purified, fractionated by gel electrophoresis and identified via mass spectrometry. Five candidate enzymes were selected and expressed in Escherichia coli. Of these, only a quinone dehydrogenase was shown to decolourize AB. Thus, this quinone dehydrogenase was identified as an AB decolourizing enzyme of Bacillus sp. LD003.

  10. A standardized model for predicting flap failure using indocyanine green dye

    NASA Astrophysics Data System (ADS)

    Zimmermann, Terence M.; Moore, Lindsay S.; Warram, Jason M.; Greene, Benjamin J.; Nakhmani, Arie; Korb, Melissa L.; Rosenthal, Eben L.

    2016-03-01

    Techniques that provide a non-invasive method for evaluation of intraoperative skin flap perfusion are currently available but underutilized. We hypothesize that intraoperative vascular imaging can be used to reliably assess skin flap perfusion and elucidate areas of future necrosis by means of a standardized critical perfusion threshold. Five animal groups (negative controls, n=4; positive controls, n=5; chemotherapy group, n=5; radiation group, n=5; chemoradiation group, n=5) underwent pre-flap treatments two weeks prior to undergoing random pattern dorsal fasciocutaneous flaps with a length to width ratio of 2:1 (3 x 1.5 cm). Flap perfusion was assessed via laser-assisted indocyanine green dye angiography and compared to standard clinical assessment for predictive accuracy of flap necrosis. For estimating flap-failure, clinical prediction achieved a sensitivity of 79.3% and a specificity of 90.5%. When average flap perfusion was more than three standard deviations below the average flap perfusion for the negative control group at the time of the flap procedure (144.3+/-17.05 absolute perfusion units), laser-assisted indocyanine green dye angiography achieved a sensitivity of 81.1% and a specificity of 97.3%. When absolute perfusion units were seven standard deviations below the average flap perfusion for the negative control group, specificity of necrosis prediction was 100%. Quantitative absolute perfusion units can improve specificity for intraoperative prediction of viable tissue. Using this strategy, a positive predictive threshold of flap failure can be standardized for clinical use.

  11. Experimental model: dye penetration of extensive interim restorations used during endodontic treatment while under load in a multiple axis chewing simulator.

    PubMed

    Jensen, Arna-Lee; Abbott, Paul V

    2007-10-01

    The purpose of this study was to design an experimental model that allowed extensive endodontic interim restorations to be tested for dye penetration while under simulated masticatory load. Extracted premolar teeth had standardized mesio-occluso-distal cavities prepared, and the root canals were instrumented. A cotton wool pellet was placed in the pulp chamber, and the cavities were restored with Cavit, IRM, Ketac-Fil Plus, Ketac-Silver, or composite resin (Z100). They were subjected to the equivalent of 3 months of clinical load while exposed to methylene blue dye. Results of this study could not support IRM as a suitable interim endodontic restorative material to use in extensive cavities. The dye penetration in the Ketac-Fil Plus and Ketac-Silver specimens was not predictable, and the results suggested Cavit and Z100 composite resin require further investigations as potentially useful materials for this purpose.

  12. Charge transfer in graphene oxide-dye system for photonic applications

    SciTech Connect

    Bongu, Sudhakara Reddy Bisht, Prem B.; Thu, Tran V.; Sandhu, Adarsh

    2014-02-20

    The fluorescence of a standard dye Rhodamine 6G (R6G) in solution decreases on addition of reduced graphene oxide (rGO). The absorption spectra and lifetime measurements confirm that no excited-state but a ground-state complex formation is responsible for this effect. For silver decorated rGO (Ag-rGO), the quenching efficiency and ground state complex formation process is small. Z-scan measurements have been done to study the optical nonlinearity at 532 nm under ps time scale. Remarkable reduction in the saturable absorption (SA) effect of R6G indicates no nonlinear contribution from the ground state complex. The results have been explained with varying charge transfer rates and non-fluorescence nature of the complex.

  13. Integrated Workforce Modeling System

    NASA Technical Reports Server (NTRS)

    Moynihan, Gary P.

    2000-01-01

    There are several computer-based systems, currently in various phases of development at KSC, which encompass some component, aspect, or function of workforce modeling. These systems may offer redundant capabilities and/or incompatible interfaces. A systems approach to workforce modeling is necessary in order to identify and better address user requirements. This research has consisted of two primary tasks. Task 1 provided an assessment of existing and proposed KSC workforce modeling systems for their functionality and applicability to the workforce planning function. Task 2 resulted in the development of a proof-of-concept design for a systems approach to workforce modeling. The model incorporates critical aspects of workforce planning, including hires, attrition, and employee development.

  14. Surface Binding and Organization of Sensitizing Dyes on Metal Oxide Single Crystal Surfaces

    SciTech Connect

    Parkinson, Bruce

    2010-06-04

    Even though investigations of dye-sensitized nanocrystalline semiconductors in solar cells has dominated research on dye-sensitized semiconductors over the past two decades. Single crystal electrodes represent far simpler model systems for studying the sensitization process with a continuing train of studies dating back more than forty years. Even today single crystal surfaces prove to be more controlled experimental models for the study of dye-sensitized semiconductors than the nanocrystalline substrates. We analyzed the scientific advances in the model sensitized single crystal systems that preceded the introduction of nanocrystalline semiconductor electrodes. It then follows the single crystal research to the present, illustrating both their striking simplicity of use and clarity of interpretation relative to nanocrystalline electrodes. Researchers have employed many electrochemical, photochemical and scanning probe techniques for studying monolayer quantities of sensitizing dyes at specific crystallographic faces of different semiconductors. These methods include photochronocoulometry, electronic spectroscopy and flash photolysis of dyes at potential-controlled semiconductor electrodes and the use of total internal reflection methods. In addition, we describe the preparation of surfaces of single crystal SnS2 and TiO2 electrodes to serve as reproducible model systems for charge separation at dye sensitized solar cells. This process involves cleaving the SnS2 electrodes and a photoelectrochemical surface treatment for TiO2 that produces clean surfaces for sensitization (as verified by AFM) resulting in near unity yields for electron transfer from the molecular excited dyes into the conduction band.

  15. Coastal Modeling System

    DTIC Science & Technology

    2014-09-04

    Coastal Inlets Research Program Coastal Modeling System The work unit develops the Coastal Modeling System ( CMS ) and conducts basic research to...further understanding of sediment transport under mixed forcing from waves and currents. The CMS is a suite of coupled two- dimensional numerical...models for simulating waves, hydrodynamics, salinity and sediment transport, and morphology change. The CMS was identified by the USACE Hydraulics and

  16. Efficient degradation of methylene blue dye over tungsten trioxide/multi-walled carbon nanotube system as a novel photocatalyst

    NASA Astrophysics Data System (ADS)

    Dinari, Mohammad; Momeni, Mohamad Mohsen; Ahangarpour, Marzieh

    2016-10-01

    Combination of acid-functionalized multi-walled carbon nanotube/tungsten trioxide (MWCNT/WO3) with different MWCNT's weight percentages as visible light-induced photocatalysts for photodegradation of methylene blue (MB) dye was synthesized. These photocatalysts were characterized by Fourier transform infrared, X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, field emission scanning electron microscopy and transmission electron microscopy techniques. Their photocatalytic activities were tested by using MB as a model compound. The results show that the MWCNT/WO3 hybrid nanostructures exhibit higher photocatalytic activity than pure WO3 or MWCNTs due to their higher absorption enhancement in visible light region and effective separation of electrons and holes. The stability of the hybrid was characterized through cyclic photocatalytic test.

  17. Generation of ultrashort dye laser pulses by transient oscillations and its applications

    NASA Astrophysics Data System (ADS)

    Hsu, Jon Shaochung

    By applying the Controlled Transient Oscillation (CTO) twice in a N2-laser-pumped dye laser system, a compact 10 ps cascade pumped dye laser was built. System performance was examined both in time and in frequency. A simple theoretical model is used to calculate the output pulse duration and power. A N2-laser side-pumped dye laser was then evaluated to improve the spatial fluctuation of the cascade pumped dye laser. A detailed study has also shown that CTO can be used to generate shorter pulses from such an oscillator. A modified cascade pumped dye laser was built and a narrower output pulse duration was measured. Higher power was achieved with a 3-stage dye amplifier chain pumped by the second harmonic of a Q-switched Nd:YAG dye amplifier chain pumped by the Q-switched Nd:YAG laser output. Two different experiments were performed with pulses from the amplified output of the modified cascade pumped CTO dye laser system. With 1.5 mJ at 566.5 nm, a laser induced plasma shutter was induced in air. Truncation speed of such a plasma shutter was further compared with results from 632.8 and 532 nm. Computer simulation appeared to be very close to the experimental results. Possibility of generating ultrashort visible laser pulses was also discussed.

  18. Preparation of nanomaterials for the ultrasound-enhanced removal of Pb(2+) ions and malachite green dye: Chemometric optimization and modeling.

    PubMed

    Dil, Ebrahim Alipanahpour; Ghaedi, Mehrorang; Asfaram, Arash; Hajati, Shaaker; Mehrabi, Fatemeh; Goudarzi, Alireza

    2017-01-01

    Copper oxide nanoparticle-loaded activated carbon (CuO-NP-AC) was synthesized and characterized using different techniques such as FE-SEM, XRD and FT-IR. It was successfully applied for the ultrasound-assisted simultaneous removal of Pb(2+) ions and malachite green (MG) dye in binary system from aqueous solution. The effect of important parameters was modeled and optimized by artificial neural network (ANN) and response surface methodology (RSM). Maximum simultaneous removal percentages (>99.0%) were found at 25mgL(-1), 20mgL(-1), 0.02g, 5min and 6.0 corresponding to initial Pb(2+) concentration, initial MG concentration, CuO-NP-AC amount, ultrasonication time and pH, respectively. The precision of the equation obtained by RSM was confirmed by the analysis of variance and calculation of correlation coefficient relating the predicted and the experimental values of ultrasound-assisted simultaneous removal of the analytes. A good agreement between experimental and predicted values was observed. A feed-forward neural network with a topology optimized by response surface methodology was successfully applied for the prediction of ultrasound-assisted simultaneous removal of Pb(2+) ions and MG dye in binary system by CuO-NPs-AC. The number of hidden neurons, MSE, R(2), number of epochs and error histogram were chosen for ANN modeling. Then, Langmuir, Freundlich, Temkin and D-R isothermal models were applied for fitting the experimental data. It was found that the Langmuir model well describes the isotherm data with a maximum adsorption capacity of 98.328 and 87.719mgg(-1) for Pb(2+) and MG, respectively. Kinetic studies at optimum condition showed that maximum Pb(2+) and MG adsorption is achieved within 5min of the start of most experiments. The combination of pseudo-second-order rate equation and intraparticle diffusion model was applicable to explain the experimental data of ultrasound-assisted simultaneous removal of Pb(2+) and MG at optimum condition obtained from RSM.

  19. The Earth System Model

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark; Rood, Richard B.; Hildebrand, Peter; Raymond, Carol

    2003-01-01

    The Earth System Model is the natural evolution of current climate models and will be the ultimate embodiment of our geophysical understanding of the planet. These models are constructed from components - atmosphere, ocean, ice, land, chemistry, solid earth, etc. models and merged together through a coupling program which is responsible for the exchange of data from the components. Climate models and future earth system models will have standardized modules, and these standards are now being developed by the ESMF project funded by NASA. The Earth System Model will have a variety of uses beyond climate prediction. The model can be used to build climate data records making it the core of an assimilation system, and it can be used in OSSE experiments to evaluate. The computing and storage requirements for the ESM appear to be daunting. However, the Japanese ES theoretical computing capability is already within 20% of the minimum requirements needed for some 2010 climate model applications. Thus it seems very possible that a focused effort to build an Earth System Model will achieve succcss.

  20. Dye laser amplifier

    DOEpatents

    Moses, Edward I.

    1992-01-01

    An improved dye laser amplifier is disclosed. The efficiency of the dye lr amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant.

  1. Dye laser amplifier

    DOEpatents

    Moses, E.I.

    1992-12-01

    An improved dye laser amplifier is disclosed. The efficiency of the dye laser amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant. 3 figs.

  2. Model-Based Systems

    NASA Technical Reports Server (NTRS)

    Frisch, Harold P.

    2007-01-01

    Engineers, who design systems using text specification documents, focus their work upon the completed system to meet Performance, time and budget goals. Consistency and integrity is difficult to maintain within text documents for a single complex system and more difficult to maintain as several systems are combined into higher-level systems, are maintained over decades, and evolve technically and in performance through updates. This system design approach frequently results in major changes during the system integration and test phase, and in time and budget overruns. Engineers who build system specification documents within a model-based systems environment go a step further and aggregate all of the data. They interrelate all of the data to insure consistency and integrity. After the model is constructed, the various system specification documents are prepared, all from the same database. The consistency and integrity of the model is assured, therefore the consistency and integrity of the various specification documents is insured. This article attempts to define model-based systems relative to such an environment. The intent is to expose the complexity of the enabling problem by outlining what is needed, why it is needed and how needs are being addressed by international standards writing teams.

  3. Photodissociation Dye Laser

    DTIC Science & Technology

    1975-04-01

    Chemical Properties of Free Radicals 5 C. Criteria for the Selection of Photodissociation Dye Laser Molecules 6 III. EXPERIMENTAL EFFORT AND...nanoseconds. In radicl systems, however, there is evidence both theoretical and experimental, that the first doublet-doublet electronic tra-jitions are...Properties, of Free Radicals Recombination is only one of many possible reaction paths that can occur in a radical system. Because they are characterized

  4. Dye-enhanced multimodal confocal microscopy for noninvasive detection of skin cancers in mouse models

    NASA Astrophysics Data System (ADS)

    Park, Jesung; Mroz, Pawel; Hamblin, Michael R.; Yaroslavsky, Anna N.

    2010-03-01

    Skin cancer is the most common form of human cancer. Its early diagnosis and timely treatment is of paramount importance for dermatology and surgical oncology. In this study, we evaluate the use of reflectance and fluorescence confocal microscopy for detecting skin cancers in an in-vivo trial with B16F10 melanoma and SCCVII squamous cell carcinoma in mice. For the experiments, the mice are anesthetized, then the tumors are infiltrated with aqueous solution of methylene blue and imaged. Reflectance images are acquired at 658 nm. Fluorescence is excited at 658 nm and registered in the range between 690 and 710 nm. After imaging, the mice are sacrificed. The tumors are excised and processed for hematoxylin and eosin histopathology, which is compared to the optical images. The results of the study indicate that in-vivo reflectance images provide valuable information on vascularization of the tumor, whereas the fluorescence images mimic the structural features seen in histopathology. Simultaneous dye-enhanced reflectance and fluorescence confocal microscopy shows promise for the detection, demarcation, and noninvasive monitoring of skin cancer development.

  5. A comparison of different activated carbon performances on catalytic ozonation of a model azo reactive dye.

    PubMed

    Gül, S; Eren, O; Kır, S; Onal, Y

    2012-01-01

    The objective of this study is to compare the performances of catalytic ozonation processes of two activated carbons prepared from olive stone (ACOS) and apricot stone (ACAS) with commercial ones (granular activated carbon-GAC and powder activated carbon-PAC) in degradation of reactive azo dye (Reactive Red 195). The optimum conditions (solution pH and amount of catalyst) were investigated by using absorbencies at 532, 220 and 280 nm wavelengths. Pore properties of the activated carbon (AC) such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N(2) adsorption. The highest BET surface area carbon (1,275 m(2)/g) was obtained from ACOS with a particle size of 2.29 nm. After 2 min of catalytic ozonation, decolorization performances of ACOS and ACAS (90.4 and 91.3%, respectively) were better than that of GAC and PAC (84.6 and 81.2%, respectively). Experimental results showed that production of porous ACs with high surface area from olive and apricot stones is feasible in Turkey.

  6. Consistent static and small-signal physics-based modeling of dye-sensitized solar cells under different illumination conditions.

    PubMed

    Cappelluti, Federica; Ma, Shuai; Pugliese, Diego; Sacco, Adriano; Lamberti, Andrea; Ghione, Giovanni; Tresso, Elena

    2013-09-21

    A numerical device-level model of dye-sensitized solar cells (DSCs) is presented, which self-consistently couples a physics-based description of the photoactive layer with a compact circuit-level description of the passive parts of the cell. The opto-electronic model of the nanoporous dyed film includes a detailed description of photogeneration and trap-limited kinetics, and a phenomenological description of nonlinear recombination. Numerical simulations of the dynamic small-signal behavior of DSCs, accounting for trapping and nonlinear recombination mechanisms, are reported for the first time and validated against experiments. The model is applied to build a consistent picture of the static and dynamic small-signal performance of nanocrystalline TiO2-based DSCs under different incident illumination intensity and direction, analyzed in terms of current-voltage characteristic, Incident Photon to Current Efficiency, and Electrochemical Impedance Spectroscopy. This is achieved with a reliable extraction and validation of a unique set of model parameters against a large enough set of experimental data. Such a complete and validated description allows us to gain a detailed view of the cell collection efficiency dependence on different operating conditions. In particular, based on dynamic numerical simulations, we provide for the first time a sound support to the interpretation of the diffusion length, in the presence of nonlinear recombination and non-uniform electron density distribution, as derived from small-signal characterization techniques and clarify its correlation with different estimation methods based on spectral measurements.

  7. Short Time Exposure (STE) test in conjunction with Bovine Corneal Opacity and Permeability (BCOP) assay including histopathology to evaluate correspondence with the Globally Harmonized System (GHS) eye irritation classification of textile dyes.

    PubMed

    Oliveira, Gisele Augusto Rodrigues; Ducas, Rafael do Nascimento; Teixeira, Gabriel Campos; Batista, Aline Carvalho; Oliveira, Danielle Palma; Valadares, Marize Campos

    2015-09-01

    Eye irritation evaluation is mandatory for predicting health risks in consumers exposed to textile dyes. The two dyes, Reactive Orange 16 (RO16) and Reactive Green 19 (RG19) are classified as Category 2A (irritating to eyes) based on the UN Globally Harmonized System for classification (UN GHS), according to the Draize test. On the other hand, animal welfare considerations and the enforcement of a new regulation in the EU are drawing much attention in reducing or replacing animal experiments with alternative methods. This study evaluated the eye irritation of the two dyes RO16 and RG19 by combining the Short Time Exposure (STE) and the Bovine Corneal Opacity and Permeability (BCOP) assays and then comparing them with in vivo data from the GHS classification. The STE test (first level screening) categorized both dyes as GHS Category 1 (severe irritant). In the BCOP, dye RG19 was also classified as GHS Category 1 while dye RO16 was classified as GHS no prediction can be made. Both dyes caused damage to the corneal tissue as confirmed by histopathological analysis. Our findings demonstrated that the STE test did not contribute to arriving at a better conclusion about the eye irritation potential of the dyes when used in conjunction with the BCOP test. Adding the histopathology to the BCOP test could be an appropriate tool for a more meaningful prediction of the eye irritation potential of dyes.

  8. Superiority of D-A-D over D-A type of organic dyes for the application in dye-sensitized solar cell

    NASA Astrophysics Data System (ADS)

    Biswas, Santu; Pramanik, Anup; Ahmed, Tasnim; Sahoo, Suman Kalyan; Sarkar, Pranab

    2016-04-01

    We study the optoelectronic properties of some recently synthesized D-A-D chromophores which are susceptible for superior intramolecular charge transfer (ICT) property. Our first principle calculations reveal that, the chromophores have enhanced charge transfer probability in the excited state in comparison to their corresponding ground states indicating faster electron injection at the interface of dye-semiconductor composites. We compute the photovoltaic properties of the dyes with and without substitution and way out a root for optimizing the device performance. Finally, dye-TiO2 QD composite systems are studied as a model for realistic photovoltaic device.

  9. Multiscale Cloud System Modeling

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo; Moncrieff, Mitchell W.

    2009-01-01

    The central theme of this paper is to describe how cloud system resolving models (CRMs) of grid spacing approximately 1 km have been applied to various important problems in atmospheric science across a wide range of spatial and temporal scales and how these applications relate to other modeling approaches. A long-standing problem concerns the representation of organized precipitating convective cloud systems in weather and climate models. Since CRMs resolve the mesoscale to large scales of motion (i.e., 10 km to global) they explicitly address the cloud system problem. By explicitly representing organized convection, CRMs bypass restrictive assumptions associated with convective parameterization such as the scale gap between cumulus and large-scale motion. Dynamical models provide insight into the physical mechanisms involved with scale interaction and convective organization. Multiscale CRMs simulate convective cloud systems in computational domains up to global and have been applied in place of contemporary convective parameterizations in global models. Multiscale CRMs pose a new challenge for model validation, which is met in an integrated approach involving CRMs, operational prediction systems, observational measurements, and dynamical models in a new international project: the Year of Tropical Convection, which has an emphasis on organized tropical convection and its global effects.

  10. Evaluation of Quantum dot immunofluorescence and a digital CMOS imaging system as an alternative to conventional organic fluorescence dyes and laser scanning for quantifying protein microarrays

    PubMed Central

    Jain, Aarti; Taghavian, Omid; Vallejo, Derek; Dotsey, Emmanuel; Schwartz, Dan; Bell, Florian G.; Greef, Chad; Davies, D. Huw; Grudzien, Jennipher; Lee, Abraham P.; Felgner, Philip; Liang, Li

    2016-01-01

    Organic fluorescent dyes are widely used for the visualization of bound antibody in a variety of immunofluorescence assays. However, the detection equipment is often expensive, fragile and hard to deploy widely. Quantum dots (Qdot®) are nanocrystals made of semiconductor materials that emit light at different wavelengths according to the size of the crystal, with increased brightness and stability. Here we have evaluated a small benchtop ‘personal’ optical imager (ArrayCAM™) developed for quantification of protein arrays probed by Qdot -based indirect immunofluorescence. The aim was to determine if the Qdot imager system provides equivalent data to the conventional organic dye-labelled antibody/laser scanner system. To do this, duplicate proteome microarrays of Vaccinia virus, Brucella melitensis and Plasmodium falciparum were probed with identical samples of immune sera, and IgG, IgA and IgM profiles visualized using biotinylated secondary antibodies followed by a tertiary reagent of streptavidin coupled to either P3 (an organic cyanine dye typically used for microarrays) or Q800 (Qdot). The data show excellent correlation for all samples tested (R>0.8) with no significant change of antibody reactivity profiles. We conclude that Qdot detection provides data equivalent to that obtained using conventional organic dye detection. The portable imager offers an economical, more robust and deployable alternative to conventional laser array scanners. PMID:26842269

  11. Interfacial modification to optimize stainless steel photoanode design for flexible dye sensitized solar cells: an experimental and numerical modeling approach

    NASA Astrophysics Data System (ADS)

    Salehi Taleghani, Sara; Zamani Meymian, Mohammad Reza; Ameri, Mohsen

    2016-10-01

    In the present research, we report fabrication, experimental characterization and theoretical analysis of semi and full flexible dye sensitized solar cells (DSSCs) manufactured on the basis of bare and roughened stainless steel type 304 (SS304) substrates. The morphological, optical and electrical characterizations confirm the advantage of roughened SS304 over bare and even common transparent conducting oxides (TCOs). A significant enhancement of about 51% in power conversion efficiency is obtained for flexible device (5.51%) based on roughened SS304 substrate compared to the bare SS304. The effect of roughening the SS304 substrates on electrical transport characteristics is also investigated by means of numerical modeling with regard to metal-semiconductor and interfacial resistance arising from the metallic substrate and nanocrystalline semiconductor contact. The numerical modeling results provide a reliable theoretical backbone to be combined with experimental implications. It highlights the stronger effect of series resistance compared to schottky barrier in lowering the fill factor of the SS304-based DSSCs. The findings of the present study nominate roughened SS304 as a promising replacement for conventional DSSCs substrates as well as introducing a highly accurate modeling framework to design and diagnose treated metallic or non-metallic based DSSCs.

  12. Computation of adsorption parameters for the removal of dye from wastewater by microwave assisted sawdust: Theoretical and experimental analysis.

    PubMed

    S, Suganya; P, Senthil Kumar; A, Saravanan; P, Sundar Rajan; C, Ravikumar

    2017-03-01

    In this research, the microwave assistance has been employed for the preparation of novel material from agro/natural bio-waste i.e. sawdust, for the effective removal of methylene blue (MB) dye from aqueous solution. The characterization of the newly prepared microwave assisted sawdust (MASD) material was performed by using FTIR, SEM and XRD analyses. In order to obtain the maximum removal of MB dye from wastewater, the adsorption experimental parameters such as initial dye concentration, contact time, solution pH and adsorbent dosage were optimized by trial and error approach. The obtained experimental results were applied to the different theoretical models to predict the system behaviour. The optimum conditions for the maximum removal MB dye from aqueous solution for an initial MB dye concentration of 25mg/L was calculated as: adsorbent dose of 3g/L, contact time of 90min, solution pH of 7.0 and at the temperature of 30°C. Freundlich and pseudo-second order models was best obeyed with the studied experimental data. Langmuir maximum monolayer adsorption capacity of MASD for MB dye removal was calculated as 58.14mg of MB dye/g of MASD. Adsorption diffusion model stated that the present adsorption system was controlled by intraparticle diffusion model. The obtained results proposed that, novel MASD was considered to be an effective and low-cost adsorbent material for the removal of dye from wastewater.

  13. A cascaded QSAR model for efficient prediction of overall power conversion efficiency of all-organic dye-sensitized solar cells.

    PubMed

    Li, Hongzhi; Zhong, Ziyan; Li, Lin; Gao, Rui; Cui, Jingxia; Gao, Ting; Hu, Li Hong; Lu, Yinghua; Su, Zhong-Min; Li, Hui

    2015-05-30

    A cascaded model is proposed to establish the quantitative structure-activity relationship (QSAR) between the overall power conversion efficiency (PCE) and quantum chemical molecular descriptors of all-organic dye sensitizers. The cascaded model is a two-level network in which the outputs of the first level (JSC, VOC, and FF) are the inputs of the second level, and the ultimate end-point is the overall PCE of dye-sensitized solar cells (DSSCs). The model combines quantum chemical methods and machine learning methods, further including quantum chemical calculations, data division, feature selection, regression, and validation steps. To improve the efficiency of the model and reduce the redundancy and noise of the molecular descriptors, six feature selection methods (multiple linear regression, genetic algorithms, mean impact value, forward selection, backward elimination, and +n-m algorithm) are used with the support vector machine. The best established cascaded model predicts the PCE values of DSSCs with a MAE of 0.57 (%), which is about 10% of the mean value PCE (5.62%). The validation parameters according to the OECD principles are R(2) (0.75), Q(2) (0.77), and Qcv2 (0.76), which demonstrate the great goodness-of-fit, predictivity, and robustness of the model. Additionally, the applicability domain of the cascaded QSAR model is defined for further application. This study demonstrates that the established cascaded model is able to effectively predict the PCE for organic dye sensitizers with very low cost and relatively high accuracy, providing a useful tool for the design of dye sensitizers with high PCE.

  14. Basic Red 51, a permitted semi-permanent hair dye, is cytotoxic to human skin cells: Studies in monolayer and 3D skin model using human keratinocytes (HaCaT).

    PubMed

    Zanoni, Thalita B; Tiago, Manoela; Faião-Flores, Fernanda; de Moraes Barros, Silvia B; Bast, Aalt; Hageman, Geja; de Oliveira, Danielle Palma; Maria-Engler, Silvya S

    2014-06-05

    The use of hair dyes is closely associated with the increase of cancer, inflammation and other skin disorders. The recognition that human skin is not an impermeable barrier indicates that there is the possibility of human systemic exposure. The carcinogenic potential of hair dye ingredients has attracted the attention of toxicologists for many decades, mainly due to the fact that some ingredients belong to the large chemical family of aromatic amines. Herein, we investigated the cytotoxicity of Basic Red 51 (BR51) in immortalized human keratinocytes (HaCaT). BR51 is a temporary hair dye that belongs to the azo group (NN); the cleavage of this bond may result in the release of toxic aromatic amines. The half maximal effective concentration (EC50) in HaCaT cells is 13μg/mL. BR51 induced a significant decrease on expression of p21 in a dose dependent manner. p53 was not affected, whereas BR51 decreased procaspase 8 and cleaved procaspase 9. These results proved that caspase 3 is fully involved in BR51-induced apoptosis. The dye was also able to stop this cell cycle on G2 in sub-toxic doses. Moreover, we reconstructed a 3D artificial epidermis using HaCaT cells; using this model, we observed that BR51 induced cell injury and cells were undergoing apoptosis, considering the fragmented nuclei. Subsequently, BR51 induced reactive oxygen species (ROS) leading to an increase on the levels of 8-oxo-dG. In conclusion, we provide strong evidence that consumer and/or professional exposure to BR51 poses risk to human health.

  15. Critical Infrastructure Modeling System

    SciTech Connect

    2004-10-01

    The Critical Infrastructure Modeling System (CIMS) is a 3D modeling and simulation environment designed to assist users in the analysis of dependencies within individual infrastructure and also interdependencies between multiple infrastructures. Through visual cuing and textual displays, a use can evaluate the effect of system perturbation and identify the emergent patterns that evolve. These patterns include possible outage areas from a loss of power, denial of service or access, and disruption of operations. Method of Solution: CIMS allows the user to model a system, create an overlay of information, and create 3D representative images to illustrate key infrastructure elements. A geo-referenced scene, satellite, aerial images or technical drawings can be incorporated into the scene. Scenarios of events can be scripted, and the user can also interact during run time to alter system characteristics. CIMS operates as a discrete event simulation engine feeding a 3D visualization.

  16. Just Dyeing to Find Out.

    ERIC Educational Resources Information Center

    Monhardt, Becky Meyer

    1996-01-01

    Presents a multidisciplinary unit on natural dyes designed to take advantage of the natural curiosity of middle school students. Discusses history of dyes, natural dyes, preparation of dyes, and the dyeing process. (JRH)

  17. Modeling Sustainable Food Systems

    NASA Astrophysics Data System (ADS)

    Allen, Thomas; Prosperi, Paolo

    2016-05-01

    The processes underlying environmental, economic, and social unsustainability derive in part from the food system. Building sustainable food systems has become a predominating endeavor aiming to redirect our food systems and policies towards better-adjusted goals and improved societal welfare. Food systems are complex social-ecological systems involving multiple interactions between human and natural components. Policy needs to encourage public perception of humanity and nature as interdependent and interacting. The systemic nature of these interdependencies and interactions calls for systems approaches and integrated assessment tools. Identifying and modeling the intrinsic properties of the food system that will ensure its essential outcomes are maintained or enhanced over time and across generations, will help organizations and governmental institutions to track progress towards sustainability, and set policies that encourage positive transformations. This paper proposes a conceptual model that articulates crucial vulnerability and resilience factors to global environmental and socio-economic changes, postulating specific food and nutrition security issues as priority outcomes of food systems. By acknowledging the systemic nature of sustainability, this approach allows consideration of causal factor dynamics. In a stepwise approach, a logical application is schematized for three Mediterranean countries, namely Spain, France, and Italy.

  18. The evaluation of electrical energy per order (E(Eo)) for photooxidative decolorization of four textile dye solutions by the kinetic model.

    PubMed

    Daneshvar, N; Aleboyeh, A; Khataee, A R

    2005-05-01

    Photooxidative decolorization of four textile dyestuffs, C.I. Acid Orange 7 (AO7), C.I. Acid Orange 8 (AO8), C.I. Acid Orange 52 (AO52) and C.I. Acid Blue 74 (AB74), by UV/H2O2 was investigated in a laboratory scale photoreactor equipped with a 15 W low pressure mercury vapour lamp. The decolorization of the dyes was found to follow pseudo-first-order kinetics, and hence the figure-of-merit electrical energy per order (E(Eo)) is appropriate for estimating the electrical energy efficiency. The E(Eo) values were found to depend on the concentration of H2O2, concentration and basic structure of the dye. This study shows that these textile dyes can be treated easily and effectively with the UV/H2O2 process with E(Eo) values between 0.4 and 5 kW h m-3 order-1, depending on the initial concentrations of dyes and H2O2. The kinetic model, based on the initial rates of degradation, provided good prediction of the E(Eo) values for a variety of conditions.

  19. Artificial neural network modeling of photocatalytic removal of a disperse dye using synthesized of ZnO nanoparticles on montmorillonite.

    PubMed

    Kıranşan, Murat; Khataee, Alireza; Karaca, Semra; Sheydaei, Mohsen

    2015-04-05

    In this study, the photocatalytic ability of ZnO/Montmorilonite (ZnO/MMT) nanocomposite under UV-A, UV-B and UV-C radiation was investigated. ZnO nanoparticles were synthesized on the surface of MMT and used as photocatalyst in decolorization of Disperse Red 54 (DR54) solution. Synthesized nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) techniques and nitrogen adsorption/desorption isotherms curves. The average width of synthesized ZnO particles is in the range of 30-45 nm. Effect of UV light regions, initial dye concentration, initial dosage of nanocomposite, and reusability of catalyst was studied on decolorization efficiency. The highest decolorization efficiency was achieved under UV-C radiation. A three-layered feed forward back propagation artificial neural network model was developed to predict the photocatalysis of DR54 under UV-C radiation. According to ANN model the ZnO/MMT dosage with a relative importance of 49.21% is the most influential parameter in the photocatalytic decolorization process.

  20. Distributed fuzzy system modeling

    SciTech Connect

    Pedrycz, W.; Chi Fung Lam, P.; Rocha, A.F.

    1995-05-01

    The paper introduces and studies an idea of distributed modeling treating it as a new paradigm of fuzzy system modeling and analysis. This form of modeling is oriented towards developing individual (local) fuzzy models for specific modeling landmarks (expressed as fuzzy sets) and determining the essential logical relationships between these local models. The models themselves are implemented in the form of logic processors being regarded as specialized fuzzy neural networks. The interaction between the processors is developed either in an inhibitory or excitatory way. In more descriptive way, the distributed model can be sought as a collection of fuzzy finite state machines with their individual local first or higher order memories. It is also clarified how the concept of distributed modeling narrows down a gap between purely numerical (quantitative) models and the qualitative ones originated within the realm of Artificial Intelligence. The overall architecture of distributed modeling is discussed along with the detailed learning schemes. The results of extensive simulation experiments are provided as well. 17 refs.

  1. Distributed generation systems model

    SciTech Connect

    Barklund, C.R.

    1994-12-31

    A slide presentation is given on a distributed generation systems model developed at the Idaho National Engineering Laboratory, and its application to a situation within the Idaho Power Company`s service territory. The objectives of the work were to develop a screening model for distributed generation alternatives, to develop a better understanding of distributed generation as a utility resource, and to further INEL`s understanding of utility concerns in implementing technological change.

  2. Climate system modeling program

    SciTech Connect

    1995-12-31

    The Climate System Modeling Project is a component activity of NSF's Climate Modeling, Analysis and Prediction Program, supported by the Atmospheric Sciences Program, Geosciences Directorate. Its objective is to accelerate progress toward reliable prediction of global and regional climate changes in the decades ahead. CSMP operates through workshops, support for post-docs and graduate students and other collaborative activities designed to promote interdisciplinary and strategic work in support of the overall objective (above) and specifically in three areas, (1) Causes of interdecadal variability in the climate system, (2) Interactions of regional climate forcing with global processes, and (3) Scientific needs of climate assessment.

  3. Modeling the earth system

    SciTech Connect

    Ojima, D.

    1992-12-31

    The 1990 Global Change Institute (GCI) on Earth System Modeling is the third of a series organized by the Office for Interdisciplinary Earth Studies to look in depth at particular issues critical to developing a better understanding of the earth system. The 1990 GCI on Earth System Modeling was organized around three themes: defining critical gaps in the knowledge of the earth system, developing simplified working models, and validating comprehensive system models. This book is divided into three sections that reflect these themes. Each section begins with a set of background papers offering a brief tutorial on the subject, followed by working group reports developed during the institute. These reports summarize the joint ideas and recommendations of the participants and bring to bear the interdisciplinary perspective that imbued the institute. Since the conclusion of the 1990 Global Change Institute, research programs, nationally and internationally, have moved forward to implement a number of the recommendations made at the institute, and many of the participants have maintained collegial interactions to develop research projects addressing the needs identified during the two weeks in Snowmass.

  4. Improvement of N-phthaloylchitosan based gel polymer electrolyte in dye-sensitized solar cells using a binary salt system.

    PubMed

    Yusuf, S N F; Azzahari, A D; Selvanathan, V; Yahya, R; Careem, M A; Arof, A K

    2017-02-10

    A binary salt system utilizing lithium iodide (LiI) as the auxiliary component has been introduced to the N-phthaloylchitosan (PhCh) based gel polymer electrolyte consisting of ethylene carbonate (EC), dimethylformamide (DMF), tetrapropylammonium iodide (TPAI), and iodine (I2) in order to improve the performance of dye-sensitized solar cell (DSSC) with efficiency of 6.36%, photocurrent density, JSC of 17.29mAcm(-2), open circuit voltage, VOC of 0.59V and fill factor, FF of 0.62. This efficiency value is an improvement from the 5.00% performance obtained by the DSSC consisting of only TPAI single salt system. The presence of the LiI in addition to the TPAI improves the charge injection rates and increases the iodide contribution to the total conductivity and both factors contribute to the increase in efficiency of the DSSC. The interaction behavior between polymer-plasticizer-salt was thoroughly investigated using EIS, FTIR spectroscopy and XRD.

  5. Integration of dye-sensitized solar cells, thermoelectric modules and electrical storage loop system to constitute a novel photothermoelectric generator.

    PubMed

    Chang, Ho; Yu, Zhi-Rong

    2012-08-01

    This study self-develops a novel type of photothermoelectric power generation modules. Dye-sensitized solar cells (DSSCs) serve as the photoelectric conversion system and a copper (Cu) heat-transfer nanofilm coating on both sides of the thermoelectric generator (TEG) acts as a thermoelectric conversion system. Thus module assembly absorbs light and generates electricity by DSSCs, and also recycles waste heat and generates power by the TEG. In addition, a set of pulsating heat pipes (PHP) filled with Cu nanofluid is placed on the cooling side to increase cooling effects and enhance the power generation efficiency. Results show that when the heat source of thermoelectric modules reaches 90 degrees C, TEG power output is increased by 85.7%. Besides, after thermoelectric modules are heated by additional heat source at 80 degrees C, the electrical energy generated by them can let a NiMH cell (1.25 V) be sufficiently charged in about 30 minutes. When photothermoelectric modules is illumined by simulated light, the temperature difference of two sides of TEG can reach 7 degrees C and the thermoelectric conversion efficiency is 2.17%. Furthermore, the power output of the thermoelectric modules is 11.48 mW/cm2, enhancing 1.4 % compared to merely using DSSCs module.

  6. Development of PVA-alginate as a matrix for enzymatic decolorization of textile dye in bioreactor system

    NASA Astrophysics Data System (ADS)

    Yanto, Dede Heri Yuli; Zahara, Syifa; Laksana, Raden Permana Budi; Anita, Sita Heris; Oktaviani, Maulida; Sari, Fahriya Puspita

    2017-01-01

    An immobilization technique using polyvinyl alcohol (PVA) crosslinked with sodium alginate as a matrix has been developed for textile dyes decolorization. Textiles use dye as an addition to the aesthetic value of the product. Dyes are generally used is a textile dye where the waste will be released directly into the waters around 2-20%. Therefore, it is important to develop an enzyme immobilization method using PVA-Alginate as a matrix. Based on the results of the study showed that the PVA-Alginate beads produced high decolorization percent compared to beads which contains only Ca-alginate alone and formula matrix is optimum at PVA 6% and alginate 1.5%. Encapsulation with boric acid at 7% showed optimum decolorization and reduction for enzyme leakage during decolorization. This study suggested that immobilization of enzymes into PVA-alginate matrix might be used as a biodecolorating agent.

  7. Incorporating multiple energy relay dyes in liquid dye-sensitized solar cells.

    PubMed

    Yum, Jun-Ho; Hardin, Brian E; Hoke, Eric T; Baranoff, Etienne; Zakeeruddin, Shaik M; Nazeeruddin, Mohammad K; Torres, Tomas; McGehee, Michael D; Grätzel, Michael

    2011-02-25

    Panchromatic response is essential to increase the light-harvesting efficiency in solar conversion systems. Herein we show increased light harvesting from using multiple energy relay dyes inside dye-sensitized solar cells. Additional photoresponse from 400-590 nm matching the optical window of the zinc phthalocyanine sensitizer was observed due to Förster resonance energy transfer (FRET) from the two energy relay dyes to the sensitizing dye. The complementary absorption spectra of the energy relay dyes and high excitation transfer efficiencies result in a 35% increase in photovoltaic performance.

  8. Passive adoptive transfer of antitumor immunity induced by laser-dye-immunoadjuvant treatment in a rat metastatic breast cancer model

    NASA Astrophysics Data System (ADS)

    Chen, Wei R.; Liu, Hong; Singhal, Anil K.; Nordquist, Robert E.

    2000-06-01

    The ideal cancer treatment modalities should not only cause tumor regression and eradication but also induce a systemic anti-tumor immunity. This is essential for control of metastatic tumors and for long-term tumor resistance. Laser immunotherapy using a laser, a laser-absorbing dye and an immunoadjuvant has induced such a long-term immunity in treatment of a mammary metastatic tumor. The successfully treated rats established total resistance to multiple subsequent tumor challenges. For further mechanistic studies of the antitumor immunity induced by this novel treatment modality, passive adoptive transfer was performed using splenocytes as immune cells. The spleen cells harvested from successfully treated tumor-bearing rats provided 100% immunity in the naive recipients. The passively protected first cohort rats were immune to tumor challenge with an increased tumor dose; their splenocytes also prevented the establishment of tumor in the second cohort of naive recipient rats. This immunity transfer was accomplished without the usually required T-cell suppression in recipients.

  9. Unveiling characteristics of a bioelectrochemical system with polarity reversion for simultaneous azo dye treatment and bioelectricity generation.

    PubMed

    Sun, Jian; Zhang, Yaping; Liu, Guoguang; Ning, Xunan; Wang, Yujie; Liu, Jingyong

    2015-09-01

    A novel bioelectrochemical system (BES) operated with polarity reversion was explored for simultaneous anaerobic/aerobic treatment of azo dye and production of bioelectricity under extremely low buffer. The Congo red was first decolorized in anode, with completed color removal in 35 h. The resultant decolorization intermediates were then mineralized after the anode reversed to aerobic biocathode, evidenced by 55 % chemical oxygen demand (COD) removal in 200 h. The mineralization efficiency was further increased to 70 % when the period of the half-cycle was prolonged to 375 h. Meanwhile, the BES produced a continuous stable positive/negative alternate voltage output under 5 mM phosphate buffer because of the self-neutralization of the accumulated protons and hydroxyl ions in electrolyte. The electrode performance was significantly improved, which was indicated by alleviated electrode polarization, due to in situ use of accumulated protons and hydroxyl ions and enhanced electron transfer in the presence of Congo red and its degradation intermediates, which resulted in 1.05-fold increases in maximum power density (67.5 vs. 32.9 mW/m(2)). An analysis of the microbial diversity in the biofilm revealed that the biofilm was dominated by facultative bacteria with functional roles in contaminant degradation and electricity generation.

  10. The Ideal Solvent for Paper Chromatography of Food Dyes.

    ERIC Educational Resources Information Center

    Markow, Peter G.

    1988-01-01

    Uses paper chromatography with food dyes to provide a simple and inexpensive basis for teaching chromatography. Provides experimental methodology and tabled results. Includes a solvent system comparison (Rf) for seven dyes and twenty-two solvents. (MVL)

  11. Dyeing behaviour of gamma irradiated cotton fabric using Lawson dye extracted from henna leaves (Lawsonia inermis)

    NASA Astrophysics Data System (ADS)

    Rehman, Fazal-ur; Adeel, Shahid; Qaiser, Summia; Ahmad Bhatti, Ijaz; Shahid, Muhammad; Zuber, Mohammad

    2012-11-01

    Dyeing behavior of gamma irradiated cotton fabric using Lawson dye extracted from henna leaves has been investigated. Cotton and dye powder are irradiated to different absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. The dyeing parameters such as dyeing time, electrolyte (salt) concentration and mordant concentrations using copper and iron as mordants are optimized. Dyeing is performed using un-irradiated and irradiated cotton with dye solutions and their color strength values are evaluated in CIE Lab system using Spectraflash -SF650. Methods suggested by International Standard Organization (ISO) have been employed to investigate the colourfastness properties such as colourfastness to light, washing and rubbing of irradiated dyed fabric. It is found that gamma ray treatment of cotton dyed with extracts of henna leaves has significantly improved the color strength as well as enhanced the rating of fastness properties.

  12. Modelling robot construction systems

    NASA Technical Reports Server (NTRS)

    Grasso, Chris

    1990-01-01

    TROTER's are small, inexpensive robots that can work together to accomplish sophisticated construction tasks. To understand the issues involved in designing and operating a team of TROTER's, the robots and their components are being modeled. A TROTER system that features standardized component behavior is introduced. An object-oriented model implemented in the Smalltalk programming language is described and the advantages of the object-oriented approach for simulating robot and component interactions are discussed. The presentation includes preliminary results and a discussion of outstanding issues.

  13. NEP systems model

    NASA Technical Reports Server (NTRS)

    George, Jeffrey A.

    1993-01-01

    A new nuclear electric propulsion (NEP) systems analysis code is discussed. The new code is modular and consists of a driver code and various subsystem models. The code models five different subsystems: (1) reactor/shield; (2) power conversion; (3) heat rejection; (4) power management and distribution (PMAD); and (5) thrusters. The code optimizes for the following design criteria: minimum mass; minimum radiator area; and low mass/low area. The code also optimizes the following parameters: separation distance; temperature ratio; pressure ratio; and transmission frequency. The discussion is presented in vugraph form.

  14. Coadsorption of Doxorubicin and Selected Dyes on Carbon Nanotubes. Theoretical Investigation of Potential Application as a pH-Controlled Drug Delivery System.

    PubMed

    Panczyk, Tomasz; Wolski, Pawel; Lajtar, Leszek

    2016-05-17

    This work shows results of a theoretical survey, based on molecular dynamics simulation, of potential applicability of doxorubicin coadsorption with various dyes molecules on/in carbon nanotubes as a drug delivery system. The central idea is to take advantage of the dyes charge distribution change upon switching the pH of the environment from neutral (physiological 7.4) to acidic one (∼5.5 which is typical for tumor tissues). This work discusses results obtained for four dye molecules revealing more or less interesting behavior. These were bromothymol blue, methyl red, neutral red, and p-phenylenediamine. All of them reveal pKa in the range 5-7 and thus will undergo protonation in that pH range. We considered coadsorption on external walls of carbon nanotubes and sequential filling of the nanotubes inner hollow space by drug and dyes. The latter approach, with the application of neutral red and p-phenylenediamine as blockers of doxorubicin, led to the most promising results. Closer analysis of these systems allowed us to state that neutral red can be particularly useful as a long-term blocker of doxorubicin encapsulated in the inner cavity of (30,0) carbon nanotube at neutral pH. At acidic pH we observed a spontaneous release of neutral red from the nanotube and unblocking of doxorubicin. We also confirmed, by analysis of free energy profiles, that unblocked doxorubicin can spontaneously leave the nanotube interior at the considered conditions. Thus, that system can realize pH controlled doxorubicin release in acidic environment of tumor tissues.

  15. Removal of binary dyes mixtures with opposite and similar charges by adsorption, coagulation/flocculation and catalytic oxidation in the presence of CeO2/H2O2 Fenton-like system.

    PubMed

    Issa Hamoud, Houeida; Finqueneisel, Gisèle; Azambre, Bruno

    2016-08-25

    In this study, the removal of binary mixtures of dyes with similar (Orange II/Acid Green 25) or opposite charges (Orange II/Malachite Green) was investigated either by simple adsorption on ceria or by the heterogeneous Fenton reaction in presence of H2O2. First, the CeO2 nanocatalyst with high specific surface area (269 m(2)/g) and small crystal size (5 nm) was characterized using XRD, Raman spectroscopy and N2 physisorption at 77 K. The adsorption of single dyes was studied either from thermodynamic and kinetic viewpoints. It is shown that the adsorption of dyes on ceria surface is highly pH-dependent and followed a pseudo-second order kinetic model. Adsorption isotherms fit well the Langmuir model with a complete monolayer coverage and higher affinity towards Orange II at pH 3, compared to other dyes. For the (Orange II/Acid Green 25) mixture, both the amounts of dyes adsorbed on ceria surface and discoloration rates measured from Fenton experiments were decreased by comparison with single dyes. This is due to the adsorption competition existing onto the same surface Ce(x+) sites and the reaction competition with hydroxyl radicals, respectively. The behavior of the (Orange II/Malachite Green) mixture is markedly different. Dyes with opposite charges undergo paired adsorption on ceria as well as homogeneous and heterogeneous coagulation/flocculation processes, but can also be removed by heterogeneous Fenton process.

  16. TiO 2 nano-porous photoelectrochemical cells (PECs) sensitized with mixed cationic/anionic dye systems: Role of the second cationic fluorescent dye on the photocurrent enhancement

    NASA Astrophysics Data System (ADS)

    Jayaweera, P. M.; Rajapaksha, R. M. S. P.; Tennakone, K.

    2005-08-01

    Bromopyrogallol red (BPR), an anionic dye material was used in nano-porous photoelectrochemical cells as the sensitizer in conjunction with a fluorescent cationic dye, rhodamineB (RhB) and acridine orange (AO). The overlap between absorption and emission spectra of BPR/RhB and the formation of a strong associated complex influences the photoelectron transfer rate to be enhanced and to produce enhanced photovoltaic properties. Fluorescence quenching studies indicate that photoexcited cationic dye materials deactivate efficiently by BPR following different mechanisms. FTIR and rR spectroscopic evidences suggest that the electrostatic interaction of fluorescent cationic dye takes place from the -SO3- group of the BPR molecule.

  17. Facile realization of efficient blocking from ZnO/TiO2 mismatch interface in dye-sensitized solar cells and precise microscopic modeling adapted by circuit analysis

    NASA Astrophysics Data System (ADS)

    Ameri, Mohsen; Samavat, Feridoun; Mohajerani, Ezeddin; Fathollahi, Mohammad-Reza

    2016-06-01

    In the present research, the effect of \\text{ZnO} -based blocking layers on the operational features of \\text{Ti}{{\\text{O}}2} -based dye-sensitized solar cells is investigated. A facile solution-based coating method is applied to prepare an interfacial highly transparent \\text{ZnO} compact blocking layer (CBL) to enhance the efficiency of dye-sensitized solar cells. Different precursor molar concentration were tested to find the optimum concentration. Optical and electrical measurements were carried out to confirm the operation of the CBLs. Morphological characterizations were performed by scanning electron microscopy (SEM) and atomic force microscopy (AFM) to investigate the structure of the compact layers. We have also developed a set of modeling procedures to extract the effective electrical parameters including the parasitic resistances and charged carrier profiles to investigate the effect of CBLs on the dye-sensitized solar cell (DSSC) performance. The adopted modeling approach should establish a versatile framework for diagnosis of DSSCs and facilitates the exploration of critical factors influencing device performance.

  18. Degradation mechanism and kinetic model for photocatalytic oxidation of PVC-ZnO composite film in presence of a sensitizing dye and UV radiation.

    PubMed

    Chakrabarti, Sampa; Chaudhuri, Basab; Bhattacharjee, Sekhar; Das, Paramita; Dutta, Binay Kanti

    2008-06-15

    White or plastic pollution has become a serious concern to the environmentalists for the last few years. Degradation of waste plastics in conventional incinerators leads to emission of carcinogenic dioxins to the atmosphere. In this work, an attempt has been made for the photocatalytic degradation of polyvinyl chloride (PVC) using ZnO as semi-conductor catalyst in the form of PVC-ZnO composite film. The surface morphology as well as the FTIR spectroscopy of the irradiated film has been critically examined. The degradation was measured by weight loss data and was found to follow a pseudo-first order rate equation. The various parameters studied were loading of the semi-conductor, intensity of UV radiation and presence of Eosin Y as a sensitizing dye. It was observed that dye-sensitization enhanced degradation of PVC to a large extent. A possible mechanism has been suggested and the corresponding rate equation has been modeled for the dye-sensitized rate of degradation. The model has been validated by the experimental data.

  19. Competitive sorption of anionic and cationic dyes onto cetylpyridinium-modified montmorillonite.

    PubMed

    Shin, Won Sik

    2008-10-01

    Single-and multi-solute competitive sorptions of anionic dyes; Eriochrome Black T (EBT), Orange II (OR) and Methyl Orange (MO) and cationic dyes; Thioflavin T (TT), Methylene Blue (MB) and Crystal Violet (CV) onto montmorillonite modified with a cationic surfactant, cetylpyridinium chloride (CP), were investigated. In single-solute sorption, the sorption affinity, as represented by Freundlich sorption coefficient (K(F)) and Langmuir sorption capacity (q(mL)), was in the order of EBT > OR > MO for anionic dyes and in the order of TT > MB > CV for cationic dyes. The sorption affinity of the cationic dye was higher than that of the anionic dye mainly due to the difference in sorption mechanisms: ion exchange to the bare montmorillonite surface plus two dimensional surface adsorption onto the pseudo-organic medium formed by the conglomeration of the long-chain hydrocarbon tail groups of the CP cation on the montmorillonite for cationic dyes vs. two dimensional surface adsorption only for anionic dyes. Three-parameter models (dual-mode and Song models) fitted better than the two-parameter models (Freundlich, Langmuir and Dubinin-Radushkevich models) due to the number of parameters involved. The conventional Dubinin-Radushkevich (D-R) model often used to classify sorption mechanisms based on the mean free energy were not able to explain the higher sorption of cationic dyes than anionic dyes. Among the tested models, the Song model was the best in predicting single-solute sorption in terms of the coefficient of determination (R2) and the sum of squared errors (SSE) values. Although both dual-mode and Song models fitted well to the sorption data, the results of asymptotic behavior analyses showed that Song model was better than dual-mode model in predicting sorption behaviors and in explaining sorption mechanisms. Competition between the solutes in the bisolute and trisolute system reduced the sorbed amount of each solute compared with that in the single-solute system

  20. (Dibenzoylmethanato)boron difluoride derivatives containing triphenylamine moieties: a new type of electron-donor/π-acceptor system for dye-sensitized solar cells.

    PubMed

    Mizuno, Yosuke; Yisilamu, Yilihamu; Yamaguchi, Tomoya; Tomura, Masaaki; Funaki, Takashi; Sugihara, Hideki; Ono, Katsuhiko

    2014-10-06

    (Dibenzoylmethanato)boron difluoride derivatives containing triphenylamine moieties were synthesized as a new type of electron-donor/π-acceptor system. These new compounds exhibited long-wavelength absorptions in the UV/Vis spectra, and reversible oxidation and reduction waves in cyclic voltammetry experiments. Their amphoteric redox properties are based on their resonance hybrid forms, in which a positive charge is delocalized on the triphenylamine moieties and a negative charge is localized on the boron atoms. Molecular orbital (MO) calculations indicate that their HOMO and LUMO energies vary with the number of phenylene rings connected to the difluoroboron-chelating ring. This is useful for optimizing the HOMO and LUMO levels to an iodine redox (I(-)/I3(-)) potential and a titanium dioxide conduction band, respectively. Dye-sensitized solar cells fabricated by using these compounds as dye sensitizers exhibited solar-to-electric power conversion efficiencies of 2.7-4.4 % under AM 1.5 solar light.

  1. Synthesis and characterization of model silica-gold core-shell nanohybrid systems to demonstrate plasmonic enhancement of fluorescence

    NASA Astrophysics Data System (ADS)

    Roy, Shibsekhar; Dixit, Chandra K.; Woolley, Robert; O'Kennedy, Richard; McDonagh, Colette

    2012-08-01

    In this work, gold-silica plasmonic nanohybrids have been synthesized as model systems which enable tuning of dye fluorescence enhancement/quenching interactions. For each system, a dye-doped silica core is surrounded by a 15 nm spacer region, which in turn is surrounded by gold nanoparticles (GNPs). The GNPs are either covalently conjugated via mercapto silanization to the spacer or encapsulated in a separate external silica shell. The intermediate spacer region can be either dye doped or left undoped to enable quenching and plasmonic enhancement effects respectively. The study indicates that there is a larger enhancement effect when GNPs are encapsulated in the outer shell compared to the system of external conjugation. This is due to the environmental shielding provided by shell encapsulation compared to the exposure of the GNPs to the solvent environment for the externally conjugated system. The fluorescence signal enhancement of the nanohybrid systems was evaluated using a standard HRP-anti-HRP fluorescence based assay platform.

  2. System of systems modeling and analysis.

    SciTech Connect

    Campbell, James E.; Anderson, Dennis James; Longsine, Dennis E.; Shirah, Donald N.

    2005-01-01

    This report documents the results of an LDRD program entitled 'System of Systems Modeling and Analysis' that was conducted during FY 2003 and FY 2004. Systems that themselves consist of multiple systems (referred to here as System of Systems or SoS) introduce a level of complexity to systems performance analysis and optimization that is not readily addressable by existing capabilities. The objective of the 'System of Systems Modeling and Analysis' project was to develop an integrated modeling and simulation environment that addresses the complex SoS modeling and analysis needs. The approach to meeting this objective involved two key efforts. First, a static analysis approach, called state modeling, has been developed that is useful for analyzing the average performance of systems over defined use conditions. The state modeling capability supports analysis and optimization of multiple systems and multiple performance measures or measures of effectiveness. The second effort involves time simulation which represents every system in the simulation using an encapsulated state model (State Model Object or SMO). The time simulation can analyze any number of systems including cross-platform dependencies and a detailed treatment of the logistics required to support the systems in a defined mission.

  3. Vital-dye-enhanced multimodal imaging of neoplastic progression in a mouse model of oral carcinogenesis

    NASA Astrophysics Data System (ADS)

    Hellebust, Anne; Rosbach, Kelsey; Wu, Jessica Keren; Nguyen, Jennifer; Gillenwater, Ann; Vigneswaran, Nadarajah; Richards-Kortum, Rebecca

    2013-12-01

    In this longitudinal study, a mouse model of 4-nitroquinoline 1-oxide chemically induced tongue carcinogenesis was used to assess the ability of optical imaging with exogenous and endogenous contrast to detect neoplastic lesions in a heterogeneous mucosal surface. Widefield autofluorescence and fluorescence images of intact 2-NBDG-stained and proflavine-stained tissues were acquired at multiple time points in the carcinogenesis process. Confocal fluorescence images of transverse fresh tissue slices from the same specimens were acquired to investigate how changes in tissue microarchitecture affect widefield fluorescence images of intact tissue. Widefield images were analyzed to develop and evaluate an algorithm to delineate areas of dysplasia and cancer. A classification algorithm for the presence of neoplasia based on the mean fluorescence intensity of 2-NBDG staining and the standard deviation of the fluorescence intensity of proflavine staining was found to separate moderate dysplasia, severe dysplasia, and cancer from non-neoplastic regions of interest with 91% sensitivity and specificity. Results suggest this combination of noninvasive optical imaging modalities can be used in vivo to discriminate non-neoplastic from neoplastic tissue in this model with the potential to translate this technology to the clinic.

  4. Vital-dye-enhanced multimodal imaging of neoplastic progression in a mouse model of oral carcinogenesis

    PubMed Central

    Hellebust, Anne; Rosbach, Kelsey; Wu, Jessica Keren; Nguyen, Jennifer; Gillenwater, Ann; Vigneswaran, Nadarajah; Richards-Kortum, Rebecca

    2013-01-01

    Abstract. In this longitudinal study, a mouse model of 4-nitroquinoline 1-oxide chemically induced tongue carcinogenesis was used to assess the ability of optical imaging with exogenous and endogenous contrast to detect neoplastic lesions in a heterogeneous mucosal surface. Widefield autofluorescence and fluorescence images of intact 2-NBDG-stained and proflavine-stained tissues were acquired at multiple time points in the carcinogenesis process. Confocal fluorescence images of transverse fresh tissue slices from the same specimens were acquired to investigate how changes in tissue microarchitecture affect widefield fluorescence images of intact tissue. Widefield images were analyzed to develop and evaluate an algorithm to delineate areas of dysplasia and cancer. A classification algorithm for the presence of neoplasia based on the mean fluorescence intensity of 2-NBDG staining and the standard deviation of the fluorescence intensity of proflavine staining was found to separate moderate dysplasia, severe dysplasia, and cancer from non-neoplastic regions of interest with 91% sensitivity and specificity. Results suggest this combination of noninvasive optical imaging modalities can be used in vivo to discriminate non-neoplastic from neoplastic tissue in this model with the potential to translate this technology to the clinic. PMID:24362926

  5. Periphyton biofilms: A novel and natural biological system for the effective removal of sulphonated azo dye methyl orange by synergistic mechanism.

    PubMed

    Shabbir, Sadaf; Faheem, Muhammad; Ali, Naeem; Kerr, Philip G; Wu, Yonghong

    2017-01-01

    Due to their large scale use, azo dyes are adversely affecting aquatic fauna and flora as well as humans. The persistent nature of sulphonated azo dyes makes them potential ecotoxic hazards. The aim of the present study was to employ a proficient, locally available biomaterial, viz. periphyton (i.e. epiphyton, epilithon or metaphyton), for removal of the azo dye, methyl orange (MO). Results showed that the periphytic biofilms are capable of completely removing comparatively high concentrations (up to 500 mg L(-1)) of MO from wastewater. The removal of MO occurs by a synergistic mechanism involving bioadsorption and biodegradation processes. The adsorption of MO by periphyton can be described by pseudo-second order kinetics. Elovich and intraparticle diffusion models as well as Langmuir equations fit well to the MO adsorption process. FTIR analysis of MO and its metabolites demonstrated biotransformation into simpler compounds within 72 h. GC-MS/MS analysis showed the conversion of MO into simpler compounds such as phenol, ethyl acetate and acetyl acetate. The results indicated that periphyton is a promising biomaterial for the complete removal of MO from wastewater and that the treatment process has the potential for in situ removal of MO at contaminated sites.

  6. Dye ingredients and energy conversion efficiency at natural dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Özbay Karakuş, Mücella; Koca, İrfan; Er, Orhan; Çetin, Hidayet

    2017-04-01

    In this work, natural dyes extracted from the same genus but different species flowers were used as sensitizer in Dye Sensitized Solar Cell (DSSC). To clearly show dye ingredients effect on electrical characteristics, the same genus flowers were selected. The dye ingredients were analyzed by Gas Chromatography Mass Spectrometer (GC-MS). The dyes were modified by a procedure that includes refluxing in acetone. All results indicate a relationship between gallic acid quantity in dyes and solar cell efficiency. To gain further insight, the solar cell parameters were obtained by using the single-diode and double-diode models and they were compared to each other. It was observed that the applied process causes a decrease in series resistance. How the modification process and gallic acid affect energy conversion efficiency were argued in detail in the frame of results that were obtained from solar cell models.

  7. Affinity partitioning of albumin and alpha-fetoprotein in an aqueous two-phase system using poly(ethylene glycol)-bound triazine dyes.

    PubMed

    Birkenmeier, G; Usbeck, E; Kopperschläger, G

    1984-01-01

    Human albumin and alpha-fetoprotein are partitioned in an aqueous two-phase system composed of 10% (w/w) Dextran and 7.5% (w/w) poly(ethylene glycol). When a small amount of poly(ethylene glycol) is replaced by Cibacron Blue F3G-A-liganded poly(ethylene glycol) the partition coefficient, K, of albumin increases by the factor of about 4000 whereas the K value of alpha-fetoprotein undergoes only a small change. The change of the partition coefficient in a logarithmic scale induced by increasing dye-polymer concentrations turned out as a useful measure for the affinity of albumin and alpha-fetoprotein to the dyes. The effect of pH and salt concentration on the affinity partition of albumin and alpha-fetoprotein is demonstrated. The partition of the two proteins in presence of Cibacron Blue F3G-A-liganded poly(ethylene glycol) is compared with seven other triazine dye-poly(ethylene glycol) derivatives.

  8. Physical Modeling of Scaled Water Distribution System Networks.

    SciTech Connect

    O'Hern, Timothy J.; Hammond, Glenn Edward; Orear, Leslie ,; van Bloemen Waanders, Bart G.; Paul Molina; Ross Johnson

    2005-10-01

    Threats to water distribution systems include release of contaminants and Denial of Service (DoS) attacks. A better understanding, and validated computational models, of the flow in water distribution systems would enable determination of sensor placement in real water distribution networks, allow source identification, and guide mitigation/minimization efforts. Validation data are needed to evaluate numerical models of network operations. Some data can be acquired in real-world tests, but these are limited by 1) unknown demand, 2) lack of repeatability, 3) too many sources of uncertainty (demand, friction factors, etc.), and 4) expense. In addition, real-world tests have limited numbers of network access points. A scale-model water distribution system was fabricated, and validation data were acquired over a range of flow (demand) conditions. Standard operating variables included system layout, demand at various nodes in the system, and pressure drop across various pipe sections. In addition, the location of contaminant (salt or dye) introduction was varied. Measurements of pressure, flowrate, and concentration at a large number of points, and overall visualization of dye transport through the flow network were completed. Scale-up issues that that were incorporated in the experiment design include Reynolds number, pressure drop across nodes, and pipe friction and roughness. The scale was chosen to be 20:1, so the 10 inch main was modeled with a 0.5 inch pipe in the physical model. Controlled validation tracer tests were run to provide validation to flow and transport models, especially of the degree of mixing at pipe junctions. Results of the pipe mixing experiments showed large deviations from predicted behavior and these have a large impact on standard network operations models.3

  9. Dye lasers. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Cavagnaro, D. M.

    1980-08-01

    This bibliography covers studies on dye laser theory, design, components, optical systems, and frequency range. Abstracts on lasing dyes, pumping, tuning, excitation, molecular structure, and modulation are included. Studies on dye laser use in spectroscopy are covered. This updated bibliography contains 217 citations, none of which are new entries to the previous edition.

  10. Benzidine Dyes Action Plan

    EPA Pesticide Factsheets

    This Action Plan addresses the use of benzidine-based dyes and benzidine congener-based dyes, both metalized and non-metalized, in products that would result in consumer exposure, such as for use to color textiles.

  11. Potential use of cotton plant wastes for the removal of Remazol Black B reactive dye.

    PubMed

    Tunç, Ozlem; Tanaci, Hacer; Aksu, Zümriye

    2009-04-15

    In this study, the potential use of cotton plant wastes - stalk (CS) and hull (CH) - as sorbents for the removal of Remazol Black B (RB5), a vinyl sulfone type reactive dye, was investigated. The results indicated that adsorption was strongly pH-dependent but slightly temperature-dependent for each sorbent-dye system. The Freundlich, Langmuir, Redlich-Peterson and Langmuir-Freundlich adsorption models were used for the mathematical description of adsorption equilibrium and isotherm constants were evaluated at 25 degrees C. All models except the Freundlich model were applicable for the description of dye adsorption by both sorbents in the concentration range studied. According to the Langmuir model, CS and CH sorbents exhibited the highest RB5 dye uptake capacities of 35.7 and 50.9 mg g(-1), respectively, at an initial pH value of 1.0. Simple mass transfer and kinetic models were applied to the experimental data to examine the mechanisms of adsorption and potential rate-controlling steps. It was found that both external mass transfer and intra-particle diffusion played an important role in the adsorption mechanisms of dye, and adsorption kinetics followed the pseudo second-order type kinetic model for each sorbent. Using the Langmuir model parameters, thermodynamic constant DeltaG degrees was also evaluated for each sorption system.

  12. Sodium heat transfer system modeling

    NASA Astrophysics Data System (ADS)

    Baker, A. F.; Fewell, M. E.

    1983-11-01

    The sodium heat transfer system of the international energy agency (IEA) small solar power systems (SSPS) central receiver system (CRS), which includes the heliostat field, receiver, hot and cold storage vessels, and sodium/water steam generator was modeled. The computer code SOLTES (simulator of large thermal energy systems), was used to model this system. The results from SOLTES are compared to measured data.

  13. Quantifying groundwater-surface water interactions using a stream energy balance model and dye tracing in a proglacial valley of the Cordillera Blanca, Peru

    NASA Astrophysics Data System (ADS)

    Somers, L. D.; Gordon, R.; McKenzie, J. M.; Lautz, L.; Wigmore, O.; Baraer, M.; Mark, B. G.

    2015-12-01

    Streams in many Andean regions provide downstream communities and industries with water sourced from both groundwater and glacier melt, such as the streams of the Cordillera Blanca, Peru, which has the highest density of glaciers in the tropics. From May to September, when precipitation is minimal, approximately half the discharge in the region's proglacial streams comes from groundwater. However, due to the remote nature of the region, there are few effective field methods to identify the spatial distribution of groundwater discharge at the reach scale. An energy balance model, Rhodamine WT dye tracing, and high-definition kite-borne imagery were used to determine gross and net groundwater inputs to a 4 km reach of the Quilcay River within Huascaran National Park, Peru. The HFLUX computer program (http://hydrology.syr.edu/hflux.html) was used to simulate the Quilcay River's energy balance using stream temperature observations, meteorological measurements, and kite-borne areal photography. Model results indicate 29% of stream discharge at the reach outlet was contributed by groundwater discharge over the study section. A constant rate Rhodamine-WT dye tracing experiment, coupled with the energy-balance model, shows that approximately 49% of stream water is exchanged (ie. no net gain) with the subsurface as gross gains and losses. The energy balance simulations suggest the largest net groundwater gains in streamflow occur in reaches situated in low gradient meadows, likely a product of the abundant springs that flow into the main channel. Dye tracing results indicate significant groundwater-surface water exchange occurs in stream sections that traverse cross-valley moraines, where connectivity between the subsurface and the stream is highest. These insights into pathways of groundwater-surface water interaction can be applied to improve hydrological modeling in proglacial catchments throughout South America.

  14. Application of central composite design and artificial neural network in modeling of reactive blue 21 dye removal by photo-ozonation process.

    PubMed

    Mehrizad, Ali; Gharbani, Parvin

    2016-01-01

    The present study deals with use of central composite design (CCD) and artificial neural network (ANN) in modeling and optimization of reactive blue 21 (RB21) removal from aqueous media under photo-ozonation process. Four effective operational parameters (including: initial concentration of RB21, O(3) concentration, UV light intensity and reaction time) were chosen and the experiments were designed by CCD based on response surface methodology (RSM). The obtained results from the CCD model were used in modeling the process by ANN. Under optimum condition (O(3) concentration of 3.95 mg L(-1), UV intensity of 20.5 W m(-2), reaction time of 7.77 min and initial dye concentration of 40.21 mg L(-1)), RB21 removal efficiency reached to up 98.88%. A topology of ANN with a three-layer consisting of four input neurons, 14 hidden neurons and one output neuron was designed. The relative significance of each major factor was calculated based on the connection weights of the ANN model. Dye and ozone concentrations were the most important variables in the photo-ozonation of RB21, followed by reaction time and UV light intensity. The comparison of predicted values by CCD and ANN with experimental results showed that both methods were highly efficient in the modeling of the process.

  15. Single and binary adsorption of reactive dyes from aqueous solutions onto clinoptilolite.

    PubMed

    Sismanoglu, Tuba; Kismir, Yasemin; Karakus, Selcan

    2010-12-15

    The adsorption of Reactive Blue 21 (RB21) and Reactive Red 195 (RR195) onto clinoptilolite type natural zeolite (ZEC) has been investigated at 298.15K. The uptake of single and binary reactive dyes from aqueous solutions has been determined by UV-vis spectroscopy. Two mono-component (RB21 and RR195) and binary component (RB21 with RR195, and RR195 with RB21), isotherms were determined. The mono-component Langmuir isotherm model was applied to experimental data and the isotherm constants were calculated for RB21 and RR195 dyes. The monolayer coverage capacities of clinoptilolite for RB21 and RR195 dyes in single solution system were found as 9.652 and 3.186 mg/g, respectively. Equilibrium adsorption for binary systems was analyzed by using the extended Langmuir models. The rate of kinetic processes of single and binary dye systems onto clinoptilolite was described by using two kinetics adsorption models. The pseudo-second-order model was the best choice among the kinetic models to describe the adsorption behaviour of single and binary dyes onto clinoptilolite.

  16. Adsorption of dyes on Sahara desert sand.

    PubMed

    Varlikli, Canan; Bekiari, Vlasoula; Kus, Mahmut; Boduroglu, Numan; Oner, Ilker; Lianos, Panagiotis; Lyberatos, Gerasimos; Icli, Siddik

    2009-10-15

    Sahara desert sand (SaDeS) was employed as a mineral sorbent for retaining organic dyes from aqueous solutions. Natural sand has demonstrated a strong affinity for organic dyes but significantly lost its adsorption capacity when it was washed with water. Therefore, characterization of both natural and water washed sand was performed by XRD, BET, SEM and FTIR techniques. It was found that water-soluble kyanite, which is detected in natural sand, is the dominant factor affecting adsorbance of cationic dyes. The sand adsorbs over 75% of cationic dyes but less than 21% for anionic ones. Among the dyes studied, Methylene Blue (MB) demonstrated the strongest affinity for Sahara desert sand (Q(e)=11.98 mg/g, for initial dye solution concentration 3.5 x 10(-5)mol/L). The effects of initial dye concentration, the amount of the adsorbent, the temperature and the pH of the solution on adsorption capacity were tested by using Methylene Blue as model dye. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied. It was concluded that adsorption of Methylene Blue on Sahara desert sand followed pseudo-second order kinetics. Gibbs free energy, enthalpy change and entropy change were calculated and found -6411 J/mol, -30360 J/mol and -76.58 J/mol K, respectively. These values indicate that the adsorption is an exothermic process and has a spontaneous nature at low temperatures.

  17. Synthesis of malachite@clay nanocomposite for rapid scavenging of cationic and anionic dyes from synthetic wastewater.

    PubMed

    Srivastava, Varsha; Sillanpää, Mika

    2017-01-01

    Synthesis of malachite@clay nanocomposite was successfully carried out for the removal of cationic (Methylene Blue, MB) and anionic dyes (Congo Red, CR) from synthetic wastewater. Nanocomposite was characterized by TEM, SEM, FT-IR, EDS analysis and zeta potential. TEM analysis indicated that the particle diameter of nanocomposite was in the range of 14 to 23nm. Various important parameters viz. contact time, concentration of dyes, nanocomposite dosage, temperature and solution pH were optimized to achieve maximum adsorption capacity. In the case of MB, removal decreased from 99.82% to 93.67% while for CR, removal decreased from 88.55% to 75.69% on increasing dye concentration from 100 to 450mg/L. pH study confirmed the higher removal of CR in acidic range while MB removal was higher in alkaline range. Kinetic study revealed the applicability of pseudo-second-order model for the adsorption of both dyes. Negative values of ΔG(0) for both systems suggested the feasibility of dye removal and support for spontaneous adsorption of CR and MB on nanocomposite. Nanocomposite showed 277.77 and 238.09mg/g Langmuir adsorption capacity for MB and CR respectively. Desorption of dyes from the dye loaded nanocomposite was easily carried out with acetone. The results indicate that the prepared malachite@clay nanocomposite is an efficient adsorbent with high adsorption capacity for the aforementioned dyes.

  18. A fluorescent codetection system for immunoblotting and proteomics through ECL-Plex and CyDye labeling.

    PubMed

    McManus, Ciara A; Donoghue, Pamela M; Dunn, Michael J

    2009-01-01

    The qualitative and quantitative capabilities of 2-D electrophoresis and its use in widespread proteome analysis has been revolutionized over the past decade with the introduction of differential gel electrophoresis commonly known as DIGE. This highly sensitive CyDye protein labeling technique now attempts to advance conventional western blotting by the combination of DIGE labeling with the recently developed ECL-Plex CyDye conjugated secondary antibodies. The ability of this method to simultaneously visualize the total protein expression profile as well as the specific immunodetection of an individual protein species will significantly aid protein validation following 2-D gel separation by confirming the exact location of proteins of interest. This simple, rapid, and reproducible technique is demonstrated by 1-D and 2-D electrophoresis through the detection of the small 27-kDa heat shock protein (hsp 27), a protein known to be expressed in the human heart, from a complex cardiac protein extract.

  19. Ultrasonic dyeing of cellulose nanofibers.

    PubMed

    Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

    2016-07-01

    Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing.

  20. Laser dye stability

    NASA Astrophysics Data System (ADS)

    Fletcher, N.

    1980-06-01

    Lasing characteristics and bleaching of four Eastman Kodak ir dyes have been examined in dimethyl sulfoxide. These ir dyes are shown to improve in performance in the absence of oxygen. Their photochemical stability was found to be comparable to the quinolone laser dyes when exposed to flashlamp excitation. Photodecomposition of the ir dyes under lasing conditions was found to vary between 1.6 and 6×10-10 moles of dye for each joule (electrical) of input energy; in comparison, the photodecomposition values for the better coumarin dyes was 0.2 to 1.0×10-10 moles/J at a concentration of 1.0×10-4 M in ethanol. It was also found that increasing the concentration of these tricarbocyanine dyes gives a marked improvement in the useful lifetime of these solutions as lasing media in the absence of oxygen.

  1. Determination of effective optical gap in dye/TiO{sub 2} systems inspired by p-n junctions

    SciTech Connect

    Hwang, Kyung-Jun; Jeong, Yonkil E-mail: widipark@gist.ac.kr; Park, Dong-Won E-mail: widipark@gist.ac.kr

    2015-04-06

    The effective optical gap and device current limits of dye-sensitized solar cells (DSCs) were investigated. Optical gap determination was based on an approach that assumes the presence of a nanoscale p-n junction in the DSCs between the bulk TiO{sub 2} semiconductor and the dye-cluster with quantum size effect. On the basis of this approach, the effective optical gap of the dye-absorber was extracted from a relation between external quantum efficiency and photon energy. The short-circuit current density of the fabricated DSCs showed a current loss in the range from 3.7 to 5.1 mA cm{sup −2} compared to the device current limit. This current loss can be mainly attributed to the light reflection of the window layer and the native charge-transfer loss by device imperfections, including subsidiary charge-transfer loss by a nanoscale Schottky junction between TiO{sub 2} and the electrolyte.

  2. Accelerated decolorization of azo dye Congo red in a combined bioanode-biocathode bioelectrochemical system with modified electrodes deployment.

    PubMed

    Kong, Fanying; Wang, Aijie; Cheng, Haoyi; Liang, Bin

    2014-01-01

    In this study, BES with bioanode and biocathode was applied to decolorize an azo dye Congo red (CR). Results showed that the Congo red decolorization efficiency (CR-DE) within 23 h in a combined bioanode-biocathode single chamber BES was 98.3±1.3%, significantly higher than that of mixed solution in a dual chamber BES (67.2±3.5%) (P<0.005). Various electrodes deployments (horizontal, vertical and surrounding) in the combined bioanode-biocathode BES were further compared based on the decolorization performance and electrochemical characterization. Results indicated that CR-DE within 11h improved from 87.4±1.3% to 97.5±2.3%, meanwhile the internal resistance decreased from 236.6 to 42.2Ω as modifying the horizontal deployment to be a surrounding deployment. It proved that the combination of bioanode and biocathode with suitable electrodes deployment could accelerate the decolorization of azo dye Congo red, which would be great potential for the application of bioelectrochemical technology in azo dye wastewater treatment.

  3. Spectroscopic investigations of a novel tricyanofuran dye for nonlinear optics.

    PubMed

    Han, Likun; Jiang, Yadong; Li, Wei; Li, Yuanxun; Hao, Peng

    2008-11-01

    A novel tricyanofuran dye was synthesized and the dye-in-polymer films were fabricated by spin-coating process. The spectroscopic properties of the dye in the solutions and polymer films were investigated by the absorption spectra and fluorescence emission spectra. It is found that the absorption and fluorescence maxima are largely red-shifted along with the increase of the solvent polarity. And the low values of fluorescence quantum yield in higher polarity solvents suggest the presence of twisted intramolecular charge transfer states of the dye. Moreover, the second order polarizability value of the novel dye was estimated based on the quantum-mechanical two-level model.

  4. Energy System Modeling with REopt

    SciTech Connect

    Simpkins, Travis; Anderson, Kate; Cutler, Dylan; Olis, Dan; Elgqvist, Emma; DiOrio, Nick; Walker, Andy

    2016-07-15

    This poster details how REopt - NREL's software modeling platform for energy systems integration and optimization - can help to model energy systems. Some benefits of modeling with REopt include optimizing behind the meter storage for cost and resiliency, optimizing lab testing, optimizing dispatch of utility scale storage, and quantifying renewable energy impact on outage survivability.

  5. ASTP ranging system mathematical model

    NASA Technical Reports Server (NTRS)

    Ellis, M. R.; Robinson, L. H.

    1973-01-01

    A mathematical model is presented of the VHF ranging system to analyze the performance of the Apollo-Soyuz test project (ASTP). The system was adapted for use in the ASTP. The ranging system mathematical model is presented in block diagram form, and a brief description of the overall model is also included. A procedure for implementing the math model is presented along with a discussion of the validation of the math model and the overall summary and conclusions of the study effort. Detailed appendices of the five study tasks are presented: early late gate model development, unlock probability development, system error model development, probability of acquisition and model development, and math model validation testing.

  6. Photoelectrocatalytic/photoelectro-Fenton coupling system using a nanostructured photoanode for the oxidation of a textile dye: Kinetics study and oxidation pathway.

    PubMed

    Almeida, Lucio C; Silva, Bianca F; Zanoni, Maria V B

    2015-10-01

    In this study, a coupled photoelectrocatalytic/photoelectro-Fenton reactor was designed to enhance the degradation efficiency of organic pollutants and tested using the azo dye Orange G as a model compound. Pt-decorated TiO2 nanotubes were used as a photoanode with an air-diffusion polytetrafluoroethylene cathode for H2O2 generation. The sum of individual effects of coupling the photoelectrocatalytic and photoelectro-Fenton processes was evaluated as a function of the decolorization and mineralization of Orange G solutions. The dye solutions were only completely decolorized in more acidic conditions (pH 3.0). The mineralization of the Orange G solutions increased in the sequence photoelectrocatalyticdye by the coupled process.

  7. Determination of minimum enzymatic decolorization time of reactive dye solution by spectroscopic & mathematical approach.

    PubMed

    Celebi, Mithat; Ozdemir, Zafer Omer; Eroglu, Emre; Altikatoglu, Melda; Guney, Ibrahim

    2015-02-01

    Synthetic dyes are very important for textile dyeing, paper printing, color photography and petroleum products. Traditional methods of dye removal include biodegradation, precipitation, adsorption, chemical degradation, photo degradation, and chemical coagulation. Dye decolorization with enzymatic reaction is an important issue for several research field (chemistry, environment) In this study, minimum decolorization time of Remazol Brilliant Blue R dye with Horseradish peroxidase enzyme was calculated using with mathematical equation depending on experimental data. Dye decolorization was determined by monitoring the absorbance decrease at the specific maximum wavelength for dye. All experiments were carried out with different initial dye concentrations of Remazol Brilliant Blue R at 25 degrees C constant temperature for 30 minutes. The development of the least squares estimators for a nonlinear model brings about complications not encountered in the case of the linear model. Decolorization times for completely removal of dye were calculated according to equation. It was shown that mathematical equation was conformed exponential curve for dye degradation.

  8. Voltage-sensitive dye imaging during functional development of the embryonic nervous system: a brief review with special thanks to Professor Larry Cohen.

    PubMed

    Momose-Sato, Yoko; Sato, Katsushige

    2015-04-01

    Investigating the developmental organization of the embryonic nervous system is one of the major challenges in the field of neuroscience. Despite their significance, functional studies on the vertebrate embryonic central nervous system (CNS) have been hampered by the technical limitations associated with conventional electrophysiological methods. The advent of optical techniques using voltage-sensitive dyes, which were developed by Dr. Cohen and his colleagues, has enabled electrical activity in living cells to be monitored noninvasively and also facilitated the simultaneous recording of neural responses from multiple regions. Using optical recording techniques, it is now possible to follow the functional organization of the embryonic CNS and image the spatiotemporal dynamics involved in the formation of this neural network. We herein briefly reviewed optical studies on the embryonic CNS with a special emphasis on methodological considerations and the study of neuronal circuit formation, which demonstrates the utility of fast voltage-sensitive dye imaging as a powerful tool for elucidating the functional organization of the embryonic CNS.

  9. Potentiometric Dye Imaging for Pheochromocytoma and Cortical Neurons with a Novel Measurement System Using an Integrated Complementary Metal-Oxide-Semiconductor Imaging Device

    NASA Astrophysics Data System (ADS)

    Kobayashi, Takuma; Tagawa, Ayato; Noda, Toshihiko; Sasagawa, Kiyotaka; Tokuda, Takashi; Hatanaka, Yumiko; Tamura, Hideki; Ishikawa, Yasuyuki; Shiosaka, Sadao; Ohta, Jun

    2010-11-01

    The combination of optical imaging with voltage-sensitive dyes is a powerful tool for studying the spatiotemporal patterns of neural activity and understanding the neural networks of the brain. To visualize the potential status of multiple neurons simultaneously using a compact instrument with high density and a wide range, we present a novel measurement system using an implantable biomedical photonic LSI device with a red absorptive light filter for voltage-sensitive dye imaging (BpLSI-red). The BpLSI-red was developed for sensing fluorescence by the on-chip LSI, which was designed by using complementary metal-oxide-semiconductor (CMOS) technology. A micro-electro-mechanical system (MEMS) microfabrication technique was used to postprocess the CMOS sensor chip; light-emitting diodes (LEDs) were integrated for illumination and to enable long-term cell culture. Using the device, we succeeded in visualizing the membrane potential of 2000-3000 cells and the process of depolarization of pheochromocytoma cells (PC12 cells) and mouse cerebral cortical neurons in a primary culture with cellular resolution. Therefore, our measurement application enables the detection of multiple neural activities simultaneously.

  10. Dynamic Modeling of ALS Systems

    NASA Technical Reports Server (NTRS)

    Jones, Harry

    2002-01-01

    The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

  11. Analysis of cytotoxicity and genotoxicity on E. coli, human blood cells and Allium cepa suggests a greater toxic potential of hair dye.

    PubMed

    Maiti, Swati; Sasmal, Kankaayan; Sinha, Sudarson Sekhar; Singh, Mukesh

    2016-02-01

    Pharmaceuticals and personal care products (PPCPs) are among the most important emerging environmental contaminants in recent time. PPCPs include wide range of cosmetics, among which hair dyes, are immensely popular in modern society. However, impact of hair dye and its residual discharged to the environment in relation to human health and ecological imbalance have not been widely studied. Based on the result of initial survey among the group of populations of eastern India, three most popular and commonly used permanent hair dyes are selected. Working sample of dye is prepared as recommended on the instructions booklet of the hair dye. The effect of three dyes is studied on Escherichia coli, human red blood cells (RBC), white blood cells (WBC) and Allium cepa bulbs by growth inhibition, hemolysis, 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay and A. cepa micronuclei assays respectively. The Lethal dose (LD) demonstrated significant differences among three dyes and the model systems. In vitro hemolytic assays performed on RBC, and MTT assays on WBC show the cytotoxic effects of hair dye. Significant growth inhibition of E. coli has also been noted. In addition, the root tips of A. cepa treated with the dye have shown major chromosomal abnormalities coupled with cell division retardation. Here low mitotic index confirm cell division retardation. Finally, results of in vitro studies of dye-DNA interactions demonstrate electrostatic interaction. Combing all these results it confirms that hair dyes are cytotoxic and may cause mutagenic effect on living cells irrespective of microbes, plant and animal system.

  12. The antioxidant glutathione in the fish cell lines EPC and BCF-2: response to model pro-oxidants as measured by three different fluorescent dyes.

    PubMed

    Jos, A; Cameán, A M; Pflugmacher, S; Segner, H

    2009-04-01

    Reduced glutathione (GSH) protects cells against injury by oxidative stress and maintains a range of vital functions. In vitro cell cultures have been used as experimental models to study the role of GSH in chemical toxicity in mammals; however, this approach has been rarely used with fish cells to date. The present study aimed to evaluate sensitivity and specificity of three fluorescent dyes for measuring pro-oxidant-induced changes of GSH contents in fish cell lines: monochlorobimane (mBCl), 5-chloromethylfluorescein diacetate (CMFDA) and 7-amino-4-chloromethylcoumarin (CMAC-blue). Two cell lines were studied, the EPC line established from a skin tumour of carp Cyprinus carpio, and BF-2 cells established from fins of bluegill sunfish Lepomis macrochirus. The cells were exposed for 6 and 24 h to low cytotoxic concentrations of pro-oxidants including hydrogen peroxide, paraquat (PQ), copper and the GSH synthesis inhibitor, L-buthionine-SR-sulfoximine (BSO). The results indicate moderate differences in the GSH response between EPC and BF-2 cells, but distinct differences in the magnitude of the GSH response for the four pro-oxidants. Further, the choice of GSH dye can critically affect the results, with CMFDA appearing to be less specific for GSH than mBCl and CMAC-blue.

  13. Potential of the aquatic fern Azolla filiculoides in biodegradation of an azo dye: modeling of experimental results by artificial neural networks.

    PubMed

    Khataee, A R; Movafeghi, A; Vafaei, F; Lisar, S Y Salehi; Zarei, M

    2013-01-01

    The potential of an aquatic fern, Azolla filiculoides, in phytoremediation of a mono azo dye solution, C.I. Acid Blue 92 (AB92), was studied. The effects of operational parameters such as reaction time, initial dye concentration, fern fresh weight, pH, temperature and reusability of the fern on biodegradation efficiency were investigated. The intermediate compounds produced by biodegradation process were analyzed using GC-MS analysis. An artificial neural network (ANN) model was developed to predict the biodegradation efficiency. The findings indicated that ANN provides reasonable predictive performance (R2 = 0.961). The effects of AB92 solutions (10 and 20 mg L(-1)) on growth, chlorophylls and carotenoids content, activity of antioxidant enzymes such as superoxide dismutase, peroxidase and catalase and formation of malondialdehyde were analyzed. AB92 generally showed inhibitory effects on the growth. Moreover, photosynthetic pigments in the fronds significantly decreased in the treatments. An increase was detected for lipid peroxidation and antioxidant enzymes activity, suggesting that AB92 caused reactive oxygen species production in Azolla fronds, which were scavenged by induced activities of antioxidant enzymes.

  14. Ultrasonic enhancement of the simultaneous removal of quaternary toxic organic dyes by CuO nanoparticles loaded on activated carbon: Central composite design, kinetic and isotherm study.

    PubMed

    Dashamiri, Somayeh; Ghaedi, Mehrorang; Dashtian, Kheibar; Rahimi, Mahmood Reza; Goudarzi, Alireza; Jannesar, Ramin

    2016-07-01

    Copper oxide nanoparticles loaded on activated carbon (CuO-NPs-AC) were prepared and fully analyzed and characterized with FE-SEM, XRD and FT-IR. Subsequently, this novel material was used for simultaneous ultrasound-assisted adsorption of brilliant green (BG), auramine O (AO), methylene blue (MB) and eosin yellow (EY) dyes. Problems regard to dyes spectra overlap in quaternary solution of this dyes were omitted by derivative spectrophotometric method. The best pH in quaternary system was studied by using one at a time method to achieved maximum dyes removal percentage. Subsequently, sonication time, adsorbent dosage and initial dyes concentrations influence on dyes removal was optimized by central composite design (CCD) combined with desirability function approach (DFA). Desirability score of 0.978 show optimum conditions set at sonication time (4.2 min), adsorbent mass (0.029 g), initial dyes concentration (4.5 mg L(-1)). Under this optimum condition the removal percentage for MB, AO, EY and BG dyes 97.58, 94.66, 96.22 and 94.93, respectively. The adsorption rate well fitted by pseudo second-order while adsorption capacity according to the Langmuir model as best equilibrium isotherm model for BG, MB, AO and EY was 20.48, 21.26, 22.34 and 21.29 mg g(-1), respectively.

  15. Synthesis and characterization of gold graphene composite with dyes as model substrates for decolorization: a surfactant free laser ablation approach.

    PubMed

    Sai Siddhardha, R S; Lakshman Kumar, V; Kaniyoor, Adarsh; Sai Muthukumar, V; Ramaprabhu, S; Podila, Ramakrishna; Rao, A M; Ramamurthy, Sai Sathish

    2014-12-10

    A facile surfactant free laser ablation mediated synthesis (LAMS) of gold-graphene composite is reported here. The material was characterized using transmission electron microscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, powdered X-ray diffraction, Raman spectroscopy, Zeta potential measurements and UV-Visible spectroscopic techniques. The as-synthesized gold-graphene composite was effectively utilized as catalyst for decolorization of 4 important textile and laser dyes. The integration of gold nanoparticles (AuNPs) with high surface area graphene has enhanced the catalytic activity of AuNPs. This enhanced activity is attributed to the synergistic interplay of pristine gold's electronic relay and π-π stacking of graphene with the dyes. This is evident when the Rhodamine B (RB) reduction rate of the composite is nearly twice faster than that of commercial citrate capped AuNPs of similar size. In case of Methylene blue (MB) the rate of reduction is 17,000 times faster than uncatalyzed reaction. This synthetic method opens door to laser ablation based fabrication of metal catalysts on graphene for improved performance without the aid of linkers and surfactants.

  16. Synthesis and characterization of gold graphene composite with dyes as model substrates for decolorization: A surfactant free laser ablation approach

    NASA Astrophysics Data System (ADS)

    Sai Siddhardha, R. S.; Lakshman Kumar, V.; Kaniyoor, Adarsh; Sai Muthukumar, V.; Ramaprabhu, S.; Podila, Ramakrishna; Rao, A. M.; Ramamurthy, Sai Sathish

    2014-12-01

    A facile surfactant free laser ablation mediated synthesis (LAMS) of gold-graphene composite is reported here. The material was characterized using transmission electron microscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, powdered X-ray diffraction, Raman spectroscopy, Zeta potential measurements and UV-Visible spectroscopic techniques. The as-synthesized gold-graphene composite was effectively utilized as catalyst for decolorization of 4 important textile and laser dyes. The integration of gold nanoparticles (AuNPs) with high surface area graphene has enhanced the catalytic activity of AuNPs. This enhanced activity is attributed to the synergistic interplay of pristine gold's electronic relay and π-π stacking of graphene with the dyes. This is evident when the Rhodamine B (RB) reduction rate of the composite is nearly twice faster than that of commercial citrate capped AuNPs of similar size. In case of Methylene blue (MB) the rate of reduction is 17,000 times faster than uncatalyzed reaction. This synthetic method opens door to laser ablation based fabrication of metal catalysts on graphene for improved performance without the aid of linkers and surfactants.

  17. Synthesis of Laser Dyes

    DTIC Science & Technology

    1988-11-09

    block number) This report describes the progress made in attempts to prepare seven laser dyes. These dyes all have a 2-(L-pyridy.)-1,3- oxazole ...structure one dye, The synthesis of one dye, 2-(Ni-met.hyl-4-pyridiniiumi)pherianthroL9,10-dJ-1,3- oxazole tosylate (I) has been com-pleted. Preliminary...1,3- oxazoles . I~ 20 [IISTRI:’UTIGTJi/AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATION 0UNITILA-,SIFIEDI.JNLiITED 0 SAME AS RPT El DTIC

  18. Rapid screening of textile dyes employed as affinity ligands to purify enzymes from yeast.

    PubMed

    Raya-Tonetti, G; Perotti, N

    1999-04-01

    A rapid method for screening potential dye ligands for use in affinity chromatography is described. Textile dyes were non-covalently coupled to a cross-linked polysaccharide Sepharose(R) matrix. Yeast alcohol dehydrogenase (ADH) was used as the model protein for evaluating the screening system. A homogenate from baker's yeast was used as the crude source of enzyme. Batchwise adsorption and elution were used to evaluate the individual dyes. The influence of pH and ionic strength in the binding and elution steps was evaluated. Batch isotherms were used to evaluate parameter characteristics. Experimental data obtained were fitted to Langmuir isotherms to determine the maximum binding capacity and the dissociation constant for each dye evaluated in this study. A dynamic binding capacity of 107.6 units of ADH/g of resin was determined for Procion Turquoise MXG dye by frontal analysis. Specific elution with NAD+ and non-specific elution with 50 mM Tris/HCl buffer, pH 8.5, were tested when Procion Turquoise MXG was used, giving purification factors of 53.5 and 4.4 respectively. This screening technique is inexpensive and can be performed in a few hours. It was possible to predict the performance of different reactive dyes in this way, and the influence of pH and salt on the binding behaviour was demonstrated.

  19. Predicting signatures of anisotropic resonance energy transfer in dye-functionalized nanoparticles.

    PubMed

    Gil, Gabriel; Corni, Stefano; Delgado, Alain; Bertoni, Andrea; Goldoni, Guido

    2016-11-13

    Resonance energy transfer (RET) is an inherently anisotropic process. Even the simplest, well-known Förster theory, based on the transition dipole-dipole coupling, implicitly incorporates the anisotropic character of RET. In this theoretical work, we study possible signatures of the fundamental anisotropic character of RET in hybrid nanomaterials composed of a semiconductor nanoparticle (NP) decorated with molecular dyes. In particular, by means of a realistic kinetic model, we show that the analysis of the dye photoluminescence difference for orthogonal input polarizations reveals the anisotropic character of the dye-NP RET which arises from the intrinsic anisotropy of the NP lattice. In a prototypical core/shell wurtzite CdSe/ZnS NP functionalized with cyanine dyes (Cy3B), this difference is predicted to be as large as 75% and it is strongly dependent in amplitude and sign on the dye-NP distance. We account for all the possible RET processes within the system, together with competing decay pathways in the separate segments. In addition, we show that the anisotropic signature of RET is persistent up to a large number of dyes per NP.

  20. Formation of a leuco spirolactone from 4-(2-carboxyphenyl)-7-diethylamino-4'-dimethylamino-1-benzopyrylium: design of a phase-change thermochromic system based on a flavylium dye.

    PubMed

    Gavara, Raquel; Laia, César A T; Parola, A Jorge; Pina, Fernando

    2010-07-12

    A phase-change thermochromic system was designed through the reversible transformation of the 4-substituted flavylium dye 4-(2-carboxyphenyl)-7-diethylamino-4'-dimethylamino-1-benzopyrylium into its leuco form, in the presence of a developer (ethyldiisopropylamine) and a suitable solvent (e.g., acetonitrile, n-pentadecanonitrile). The leuco form of the flavylium-based dye is a spirolactone species whose ring opens at low temperature (below the solvent melting point) to form the blue flavylium cation. Decarboxylation of the lactone to give 4-phenyl-7-diethylamino-4'-dimethylamino-1-benzopyrylium was observed upon irradiation of the system with UV light, erasing the thermochromic effect.

  1. Adsorption of organic dyes on TiO2 surfaces in dye-sensitized solar cells: interplay of theory and experiment.

    PubMed

    Anselmi, Chiara; Mosconi, Edoardo; Pastore, Mariachiara; Ronca, Enrico; De Angelis, Filippo

    2012-12-14

    First-principles computer simulations can contribute to a deeper understanding of the dye/semiconductor interface lying at the heart of Dye-sensitized Solar Cells (DSCs). Here, we present the results of simulation of dye adsorption onto TiO(2) surfaces, and of their implications for the functioning of the corresponding solar cells. We propose an integrated strategy which combines FT-IR measurements with DFT calculations to individuate the energetically favorable TiO(2) adsorption mode of acetic acid, as a meaningful model for realistic organic dyes. Although we found a sizable variability in the relative stability of the considered adsorption modes with the model system and the method, a bridged bidentate structure was found to closely match the FT-IR frequency pattern, also being calculated as the most stable adsorption mode by calculations in solution. This adsorption mode was found to be the most stable binding also for realistic organic dyes bearing cyanoacrylic anchoring groups, while for a rhodanine-3-acetic acid anchoring group, an undissociated monodentate adsorption mode was found to be of comparable stability. The structural differences induced by the different anchoring groups were related to the different electron injection/recombination with oxidized dye properties which were experimentally assessed for the two classes of dyes. A stronger coupling and a possibly faster electron injection were also calculated for the bridged bidentate mode. We then investigated the adsorption mode and I(2) binding of prototype organic dyes. Car-Parrinello molecular dynamics and geometry optimizations were performed for two coumarin dyes differing by the length of the π-bridge separating the donor and acceptor moieties. We related the decreasing distance of the carbonylic oxygen from the titania to an increased I(2) concentration in proximity of the oxide surface, which might account for the different observed photovoltaic performances. The interplay between theory

  2. Equilibrium modeling and kinetic studies on the adsorption of basic dye by a low-cost adsorbent: coconut (Cocos nucifera) bunch waste.

    PubMed

    Hameed, B H; Mahmoud, D K; Ahmad, A L

    2008-10-01

    In this paper, the ability of coconut bunch waste (CBW), an agricultural waste available in large quantity in Malaysia, to remove basic dye (methylene blue) from aqueous solution by adsorption was studied. Batch mode experiments were conducted at 30 degrees C to study the effects of pH and initial concentration of methylene blue (MB). Equilibrium adsorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The adsorption isotherm data were fitted well to Langmuir isotherm and the monolayer adsorption capacity was found to be 70.92 mg/g at 30 degrees C. The kinetic data obtained at different concentrations have been analyzed using a pseudo-first-order, pseudo-second-order equation and intraparticle diffusion equation. The experimental data fitted very well the pseudo-second-order kinetic model.

  3. Integrated Modeling Systems

    DTIC Science & Technology

    1989-01-01

    Summer 1979). WMSI Working Paper No. 291A. 173 Dyer , J. and R. Sarin. "Measurable Multiattribute Value Functions," Operations Research. 27:4 (July...J. McCall. "Expected Utility Maximizing Job Search," Chapter 7 of Studies in the Economics of Search, 1979, North-Holland. WMSI Working Paper No. 274...model integration, solver integration, and integration of various utilities . Model integration is further divided into four subtypes based on a four-level

  4. Stepped light-induced transient measurements of photocurrent and voltage in dye-sensitized solar cells: application for highly viscous electrolyte systems.

    PubMed

    Nakade, Shogo; Kanzaki, Taisuke; Wada, Yuji; Yanagida, Shozo

    2005-11-08

    To measure electron diffusion coefficients (D) and electron lifetimes (tau) of dye-sensitized solar cells (DSC), we introduced stepped light-induced transient measurements of photocurrent and voltage (SLIM-PCV), which can simplify the optical setup and reduce measurement time in comparison to conventional time-of-flight and frequency-modulated measurements. The method was applied to investigate the influence of the viscosity of a thermally stable high-boiling-point solvent on the energy conversion efficiency of DSCs. By systematic study of the influence of the viscosity, the species of cations as the counter charge of I(-)/I(3)(-), and the concentrations of electrolytes, we concluded that a lower dye cation reduction rate due to slower iodine diffusion is a limiting factor for a highly viscous electrolyte system. On the other hand, comparable values of D and increased values of tau were observed in a highly viscous electrolyte. By employing 0.5 M TBAI and 0.05 M I(2) in propylene carbonate, the efficiency of the DSC became comparable to that of a DSC using conventional electrolytes consisting of LiI, imidazolium iodide, and 4-tert-butylpyridine in methoxyacetonitrile. The simultaneous evaluation of D and tau through the appropriately simple measurement realizes fast optimization of the efficient and reliable DSC composed of thermally stable but often viscous electrolytes.

  5. Contributions of the electrostatic and the dispersion interaction to the solvent shift in a dye-polymer system, as investigated by hole-burning spectroscopy

    NASA Astrophysics Data System (ADS)

    Kador, L.; Jahn, S.; Haarer, D.; Silbey, R.

    1990-06-01

    Persistent spectral holes burned in the system octaethylporphin in poly(styrene) exhibit a symmetrical broadening varying in a linear fashion upon application of a static electric field. This effect is due to permanent electric-dipole moments induced in the dye molecules by the electric ``matrix field.'' The average value of the dipole-moment difference μ between the excited and the ground state of the guest molecules, which can be deduced from the broadening, shows a distinct increase from the blue to the red edge of the inhomogeneous absorption band, thus reflecting the varying dye-matrix interaction for centers with different solvent shift. A detailed analysis of this variation in the framework of a microscopic theory, based on a recent publication by Laird and Skinner [J. Chem. Phys. 90, 3274 (1989)], leads to the conclusion that the solvent shift of the absorption lines and also the μ variation across the inhomogeneous band is largely dominated by the dispersion interaction. The electrostatic contribution to the line shift is smaller by about 2 orders of magnitude.

  6. SP-100 control system modeling

    NASA Technical Reports Server (NTRS)

    Meyer, R. A.; Halfen, F. J.; Alley, A. D.

    1987-01-01

    SP-100 Control Systems modeling was done using a thermal hydraulic transient analysis model called ARIES-S. The ARIES-S Computer Simulation provides a basis for design, integration and analysis of the reactor including the control and protection systems. It is a modular digital computer simulation written in FORTRAN that operates interactively in real time on a VAX minicomputer.

  7. Optical properties of natural dyes on the dye-sensitized solar cells (DSSC) performance

    NASA Astrophysics Data System (ADS)

    Pratiwi, D. D.; Nurosyid, F.; Supriyanto, A.; Suryana, R.

    2016-11-01

    This study reported several natural dyes for application in dye-sensitized solar cells (DSSC). This study aims was to determine the effect of optical absorption properties of natural dyes on efficiency of DSSC. The sandwich structure of DSSC consist of TiO2 as working electrode, carbon layer as counter electrode, natural dyes as photosensitizer, and electrolyte as electron transfer media. The natural dyes used in this experiment were extracted from dragon fruit anthocyanin, mangosteen peels anthocyanin, and red cabbage anthocyanin. The absorbance of dyes solutions and the adsorption of the dye on the surface of TiO2 were characterized using UV-Vis spectrophotometer, the quantum efficiency versus wavelength was characterized using incident photon-to-current efficiency (IPCE) measurement system, and the efficiency of DSSC was calculated using I-V meter. UV-Vis characteristic curves showed that wavelength absorption of anthocyanin dye of red cabbage was 450 - 580 nm, anthocyanin of mangosteen peels was 400 - 480 nm, and anthocyanin of dragon fruit was 400 - 650 nm. Absorption spectra of the dye adsorption on the surface of TiO2 which was resulted in the highest absorbance of red cabbage anthocyanin. IPCE characteristic curves with anthocyanin dye of red cabbage, mangosteen peels anthocyanin, and dragon fruit anthocyanin resulted quantum efficiency of 0.058%; 0.047%; and 0.043%, respectively at wavelength maximum about 430 nm. I-V characteristic curves with anthocyanin dye of red cabbage, mangosteen peels anthocyanin, and dragon fruit anthocyanin resulted efficiency of 0.054%; 0.042%; and 0.024%, respectively.

  8. Universal low-temperature MWCNT-COOH-based counter electrode and a new thiolate/disulfide electrolyte system for dye-sensitized solar cells.

    PubMed

    Hilmi, Abdulla; Shoker, Tharallah A; Ghaddar, Tarek H

    2014-06-11

    A new thiolate/disulfide organic-based electrolyte system composed of the tetrabutylammonium salt of 2-methyl-5-trifluoromethyl-2H-[1,2,4]triazole-3-thiol (S(-)) and its oxidized form 3,3'-dithiobis(2-methyl-5-trifluoromethyl-2H-[1,2,4]triazole) (DS) has been formulated and used in dye-sensitized solar cells (DSSCs). The electrocatalytic activity of different counter electrodes (CEs) has been evaluated by means of measuring J-V curves, cyclic voltammetry, Tafel plots, and electrochemical impedance spectroscopy. A stable and low-temperature CE based on acid-functionalized multiwalled carbon nanotubes (MWCNT-COOH) was investigated with our S(-)/DS, I(-)/I3(-), T(-)/T2, and Co(II/III)-based electrolyte systems. The proposed CE showed superb electrocatalytic activity toward the regeneration of the different electrolytes. In addition, good stability of solar cell devices based on the reported electrolyte and CE was shown.

  9. Propulsive Reaction Control System Model

    NASA Technical Reports Server (NTRS)

    Brugarolas, Paul; Phan, Linh H.; Serricchio, Frederick; San Martin, Alejandro M.

    2011-01-01

    This software models a propulsive reaction control system (RCS) for guidance, navigation, and control simulation purposes. The model includes the drive electronics, the electromechanical valve dynamics, the combustion dynamics, and thrust. This innovation follows the Mars Science Laboratory entry reaction control system design, and has been created to meet the Mars Science Laboratory (MSL) entry, descent, and landing simulation needs. It has been built to be plug-and-play on multiple MSL testbeds [analysis, Monte Carlo, flight software development, hardware-in-the-loop, and ATLO (assembly, test and launch operations) testbeds]. This RCS model is a C language program. It contains two main functions: the RCS electronics model function that models the RCS FPGA (field-programmable-gate-array) processing and commanding of the RCS valve, and the RCS dynamic model function that models the valve and combustion dynamics. In addition, this software provides support functions to initialize the model states, set parameters, access model telemetry, and access calculated thruster forces.

  10. Effect of mercerization and gamma irradiation on the dyeing behaviour of cotton using stilbene based direct dye

    NASA Astrophysics Data System (ADS)

    Bhatti, Ijaz Ahmad; Adeel, Shahid; Fazal-ur-Rehman; Irshad, Misbah; Abbas, Muhammad

    2012-07-01

    The dyeing behaviour of mercerized and gamma irradiated cotton fabric using stilbene based direct dye has been investigated. The fabric was treated with different concentrations of alkali to optimize the mercerization. The optimum mercerized cotton fabric was irradiated to absorbed doses of 2, 4, 6, 8 and 10 kGy using Cs-137 gamma irradiator. Dyeing was performed using irradiated and un-irradiated cotton with dye solutions. The dyeing parameters such as temperature, time of dyeing, pH of dyeing solutions and salt concentration were optimized. The colour strength values of dyed fabrics were evaluated by comparing irradiated and un-irradiated cotton in CIE Lab system using Spectra flash SF650. Methods suggested by International Standard Organization (ISO) were employed to study the effect of gamma irradiation on the colourfastness properties of dyed fabric. It was found that mercerized and irradiated cotton have not only improved the colour strength but enhanced the rating of fastness properties also.

  11. Moments distributions of single dye molecule spectra in a low-temperature polymer: Analysis of system ergodicity

    NASA Astrophysics Data System (ADS)

    Anikushina, T. A.; Naumov, A. V.

    2013-12-01

    This article demonstrates the principal advantages of the technique for analysis of the long-term spectral evolution of single molecules (SM) in the study of the microscopic nature of the dynamic processes in low-temperature polymers. We performed the detailed analysis of the spectral trail of single tetra-tert-butylterrylene (TBT) molecule in an amorphous polyisobutylene matrix, measured over 5 hours at T = 7K. It has been shown that the slow temporal dynamics is in qualitative agreement with the standard model of two-level systems and stochastic sudden-jump model. At the same time the distributions of the first four moments (cumulants) of the spectra of the selected SM measured at different time points were found not consistent with the standard theory prediction. It was considered as evidence that in a given time interval the system is not ergodic

  12. Expert system for groundwater modeling

    SciTech Connect

    Venoge, T.P. de; Stauffer, T.B.; Medina, M.; Jacobs, T.

    1994-12-31

    Hazardous waste site remedial investigations and feasibility studies generally involve some degree of groundwater modeling. A plethora of models exist and most models are difficult to use. An expert system has been developed to lead the user to the appropriate model(s) based on responses to questions about site conditions and data availability. The system is menu driven, user friendly, and provides assistance in estimating input parameters where field measurements are lacking. The system contains twelve models, both analytical and numerical models, that are in the public domain. Some of the models included in the system are MOC, MODFLOW, BIOPLUME, RESSQ, TDAST and PLUME2D. Preprocessors and post processors have been written to permit easy data input and to provide understandable and interpretable data output. There are two versions of the expert system that are available. One version is a UNIX based system that works through the windows environment and provides excellent graphics capabilities. The other version is DOS based and will run on a 386 processor or higher system with 10 megabytes of available hard disk space.

  13. Microencapsulated Fluorescent Dye Penetrant.

    DTIC Science & Technology

    1979-07-01

    Microencapsulated fluorescent dye pentrant materials were evaluated for feasibility as a technique to detect cracks on metal surfaces when applied as...a free flowing dry powder. Various flourescent dye solutions in addition to a commercial penetrant (Zyglo ZL-30) were microencapsulated and tested on

  14. Oxazine laser dyes

    DOEpatents

    Hammond, Peter R.; Field, George F.

    1992-01-01

    New oxazine compounds useful as dye laser media in solution, are superiior to prior art materials. The oxazine dyes useful when pumped by the 578.2 nm copper line to operate in the 700-800 nm range are described by formula I ##STR1##

  15. Study of the release of a microencapsulated acid dye in polyamide dyeing using mixed cationic liposomes.

    PubMed

    de Sousa, Isabel S C; Castanheira, Elisabete M S; Rocha Gomes, Jaime I N; Real Oliveira, M Elisabete C D

    2011-06-01

    The main objective of this work was to increase the retarding effect of the acid dye Telon(®) Blue RR (C.I. Acid Blue 62; DyStar, Frankfurt, Germany) release on polyamide fibres dyeing by encapsulation of the dye in liposomes as an alternative to synthetic auxiliaries, in order to reduce effluent pollution. The retarding effect achieved with the use of mixed cationic liposomes of dioctadecyldimethylammonium bromide (DODAB)/soybean lecithin (containing a 10% molar fraction of DODAB) was better in comparison with either pure soybean lecithin liposomes or synthetic auxiliaries. The retarding effect of liposomes on the dye release was analysed through changes in the absorption and fluorescence spectra of the acid dye at different conditions. The effect of temperature (in the range of 25 °C - 70 °C) on the spectroscopic behaviour of the dye in the absence and in presence of polyamide was also studied, in order to simulate the dyeing conditions. Exhaustion curves obtained in dyeing experiments showed that, below 45 °C, the retarding effect of the mixed liposomes (lecithin/DODAB (9:1)) was similar to that of the auxiliaries, but better than the one of pure lecithin liposomes. At higher temperatures (above 45 °C), the system lecithin/DODAB presents a better performance, achieving a higher final exhaustion level when compared with the commercial leveling agent without losing the smoothing effect of lecithin.

  16. Flight Model Discharge System.

    DTIC Science & Technology

    1987-04-01

    will immediately remove the charge from the front surface of the dielectric and return it to ground. The 2-hour time constant network will then reset the...ATDP programs. NEWT5 permits the digitized input of board and component position data, while ATDP automates certain phases of input and output table...format. 8.5 RESULTS The system-level results are presented as curves of AR (normalized radiator area) versus THOT and as curves of Q (heater

  17. ASN reputation system model

    NASA Astrophysics Data System (ADS)

    Hutchinson, Steve; Erbacher, Robert F.

    2015-05-01

    Network security monitoring is currently challenged by its reliance on human analysts and the inability for tools to generate indications and warnings for previously unknown attacks. We propose a reputation system based on IP address set membership within the Autonomous System Number (ASN) system. Essentially, a metric generated based on the historic behavior, or misbehavior, of nodes within a given ASN can be used to predict future behavior and provide a mechanism to locate network activity requiring inspection. This will provide reinforcement of notifications and warnings and lead to inspection for ASNs known to be problematic even if initial inspection leads to interpretation of the event as innocuous. We developed proof of concept capabilities to generate the IP address to ASN set membership and analyze the impact of the results. These results clearly show that while some ASNs are one-offs with individual or small numbers of misbehaving IP addresses, there are definitive ASNs with a history of long term and wide spread misbehaving IP addresses. These ASNs with long histories are what we are especially interested in and will provide an additional correlation metric for the human analyst and lead to new tools to aid remediation of these IP address blocks.

  18. Monolithic dye laser amplifier

    DOEpatents

    Kuklo, T.C.

    1993-03-30

    A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

  19. Monolithic dye laser amplifier

    DOEpatents

    Kuklo, Thomas C.

    1993-01-01

    A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

  20. Adsorption kinetics of a basic dye from aqueous solutions onto apricot stone activated carbon.

    PubMed

    Demirbas, E; Kobya, M; Sulak, M T

    2008-09-01

    The preparation of activated carbon from apricot stone with H(2)SO(4) activation and its ability to remove a basic dye, astrazon yellow 7 GL, from aqueous solutions were reported in this study. The adsorbent was characterized by FTIR, BET and SEM, respectively. The effects of various experimental parameters, such as initial dye concentration, pH, adsorbent dosage and temperature were investigated in a batch-adsorption technique. The optimum conditions for removal of the basic dye were found to be pH 10, 6g/l of adsorbent dosage and equilibrium time of 35 min, respectively. A comparison of three kinetic models, the pseudo first-order, second-order and diffusion controlled kinetic models, on the basic dye-adsorbent system showed that the removal rate was heavily dependent on diffusion controlled kinetic models. The adsorption isotherm data were fitted well to Langmuir and Freundlich isotherms. The adsorption capacity was calculated as 221.23 mg/g at 50 degrees C. Thermodynamics parameters were also evaluated. The values of enthalpy and entropy were 49.87 kJ/mol and 31.93 J/mol K, respectively, indicating that this process was spontaneous and endothermic. The experimental studies were indicated that ASC had the potential to act as an alternative adsorbent to remove the basic dye from aqueous solutions.

  1. Response surface modeling of photogenerated charge collection of silver-based plasmonic dye-sensitized solar cell using central composite design experiments

    NASA Astrophysics Data System (ADS)

    Buda, Samaila; Shafie, Suhaidi; Rashid, Suraya Abdul; Jaafar, Haslina; Khalifa, Ali

    In this study, silver nanoparticles (AgNP) have been prepared and successfully incorporated in TiO2 nanopowder and used in dye-sensitized solar cell as photoanode. The effect of the AgNP concentration and photoanode film thickness on the charge collection efficiency of a photogenerated electron at the external circuit was investigated using response surface methodology. A multiple regression analysis of second order polynomial was employed to fit the experimental data and an empirical model was subsequently developed using analysis of variance (ANOVA). The results show that two independent variables (AgNP concentration and photoanode film thickness) have significantly influenced the charge collection efficiency of the silver-based plasmonic DSSC. An optimum charge collection of 64.3% was obtained at AgNP concentration and film thickness of 5%wt and 10 μm, respectively.

  2. Significance of hair-dye base-induced sensory irritation.

    PubMed

    Fujita, F; Azuma, T; Tajiri, M; Okamoto, H; Sano, M; Tominaga, M

    2010-06-01

    Oxidation hair-dyes, which are the principal hair-dyes, sometimes induce painful sensory irritation of the scalp caused by the combination of highly reactive substances, such as hydrogen peroxide and alkali agents. Although many cases of severe facial and scalp dermatitis have been reported following the use of hair-dyes, sensory irritation caused by contact of the hair-dye with the skin has not been reported clearly. In this study, we used a self-assessment questionnaire to measure the sensory irritation in various regions of the body caused by two model hair-dye bases that contained different amounts of alkali agents without dyes. Moreover, the occipital region was found as an alternative region of the scalp to test for sensory irritation of the hair-dye bases. We used this region to evaluate the relationship of sensitivity with skin properties, such as trans-epidermal water loss (TEWL), stratum corneum water content, sebum amount, surface temperature, current perception threshold (CPT), catalase activities in tape-stripped skin and sensory irritation score with the model hair-dye bases. The hair-dye sensitive group showed higher TEWL, a lower sebum amount, a lower surface temperature and higher catalase activity than the insensitive group, and was similar to that of damaged skin. These results suggest that sensory irritation caused by hair-dye could occur easily on the damaged dry scalp, as that caused by skin cosmetics reported previously.

  3. Relocatable Coastal Modeling System

    DTIC Science & Technology

    2016-06-07

    These relationships are stored on a variable-resolution grid (illustrated in figure 1b below) with sampling of 1 degree in deep water (and in data...version is referred to as MODAS2.1, which is now operational at NAVO. The NOMADS interface is being replaced by a system-independent, web -based version...inside the user’s web browser plus Perl CGI scripts which ran on a webserver. This permitted the user to run MODAS (and POM and other modules as they are

  4. Generic Distributed Systems Model

    DTIC Science & Technology

    1989-03-01

    networking of microcomputers or work- stations with a distributed system and a clear distinction between the two needs to be made. What is expected in a...INFORM.AT1ON PERTAI NING TO LOCATIONS AND POLICY CAN BE COMBINED WITH THE INITIAL DIAGRAM TO PRODUCE A PARTITIONED DFD. THE BOLD LINES REPRESENT SERVICES WHICH...PRA85] D.K. Pradhan, "Fault-tolerant. mIltiprocessor link and bus network Architectures," IEEE Trans. on Computers, Vol. 34, No. I, Jan. 1985, pp. 33

  5. Flight Model Discharge System.

    DTIC Science & Technology

    1986-02-01

    of adverse space-environmental conditions. Operational .Jrtcr-,tcsof tLe entire, s*ystem are llreseilted, including the electrostatic analyzers, * so... health diagnostics (i.e., temperature, voltages, and currents). The technical discussion which follows presents the results of the second year’s effort on...TIME, s ECLIPSE CHARGING - -2 LU; -J-3 0 Lu -4 O KAPTON TO SPACECRAFTz Lu cr -5 LL SLt -SPACECRAFT a - TO SPACE -7 -8 F 0 200 400 600 800 TIME,s (𔃻

  6. Statistical Optimization of Conditions for Decolorization of Synthetic Dyes by Cordyceps militaris MTCC 3936 Using RSM

    PubMed Central

    Kaur, Baljinder; Kumar, Balvir; Kaur, Navneet

    2015-01-01

    In the present study, the biobleaching potential of white rot fungus Cordyceps militaris MTCC3936 was investigated. For preliminary screening, decolorization properties of C. militaris were comparatively studied using whole cells in agar-based and liquid culture systems. Preliminary investigation in liquid culture systems revealed 100% decolorization achieved within 3 days of incubation for reactive yellow 18, 6 days for reactive red 31, 7 days for reactive black 8, and 11 days for reactive green 19 and reactive red 74. RSM was further used to study the effect of three independent variables such as pH, incubation time, and concentration of dye on decolorization properties of cell free supernatant of C. militaris. RSM based statistical analysis revealed that dye decolorization by cell free supernatants of C. militaris is more efficient than whole cell based system. The optimized conditions for decolorization of synthetic dyes were identified as dye concentration of 300 ppm, incubation time of 48 h, and optimal pH value as 5.5, except for reactive red 31 (for which the model was nonsignificant). The maximum dye decolorizations achieved under optimized conditions for reactive yellow 18, reactive green 19, reactive red 74, and reactive black 8 were 73.07, 65.36, 55.37, and 68.59%, respectively. PMID:25722980

  7. A method for dye extraction using an aqueous two-phase system: Effect of co-occurrence of contaminants in textile industry wastewater.

    PubMed

    Borges, Gabriella Alexandre; Silva, Luciana Pereira; Penido, Jussara Alves; de Lemos, Leandro Rodrigues; Mageste, Aparecida Barbosa; Rodrigues, Guilherme Dias

    2016-12-01

    This paper reports a green and efficient procedure for extraction of the dyes Malachite Green (MG), Methylene Blue (MB), and Reactive Red 195 (RR) using an aqueous two-phase system (ATPS). An ATPS consists mainly of water, together with polymer and salt, and does not employ any organic solvent. The extraction efficiency was evaluated by means of the partition coefficients (K) and residual percentages (%R) of the dyes, under different experimental conditions, varying the tie-line length (TLL) of the system, the pH, the type of ATPS-forming electrolyte, and the type of ATPS-forming polymer. For MG, the best removal (K = 4.10 × 10(4), %R = 0.0069%) was obtained with the ATPS: PEO 1500 + Na2C4H4O6 (TLL = 50.21% (w/w), pH = 6.00). For MB, the maximum extraction (K = 559.9, %R = 0.258%) was achieved with the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 1.00). Finally for RR, the method that presented the best results (K = 3.75 × 10(4), %R = 0.237%) was the ATPS: PEO 400 + Na2SO4 (TLL = 50.31% (w/w), pH = 6.00). The method was applied to the recovery of these dyes from a textile effluent sample, resulting in values of K of 1.17 × 10(4), 724.1, and 3.98 × 10(4) for MG, MB, and RR, respectively, while the corresponding %R values were 0.0038, 0.154, and 0.023%, respectively. In addition, the ATPS methodology provided a high degree of color removal (96.5-97.95%) from the textile effluent.

  8. Photostability of luminescent dyes in solid-state dye lasers

    NASA Astrophysics Data System (ADS)

    Weiss, Aryeh M.; Yariv, Eli; Reisfeld, Renata

    2003-10-01

    Fluorescence photobleaching was measured in dye-impregnated sol-gel/polymer composite glasses. These fluorescent glasses were used as the gain medium in a transverse-pumped solid-state dye laser. In this configuration, the fluorescent glass was excited by a pulsed Nd:YAG laser (about 6 mJ/pulse) either while placed in an optical cavity (i.e., functioning as a pulsed laser) or with the optical cavity blocked, so that lasing did not occur. The decay of the fluorescence signal versus cumulative excitation energy was recorded. We found that the rate of photobleaching decreased when the glass was lasing, as compared to the case where the optical cavity was blocked. This paper presents these results, and suggests a simple kinetic model that may explain this phenomenon.

  9. Efficiency enhancement in solid state dye sensitized solar cells by including inverse opals with controlled layer thicknesses

    NASA Astrophysics Data System (ADS)

    Zheng, Hanbin; Shah, Said Karim; Abbas, Mamatimin; Ly, Isabelle; Rivera, Thomas; Almeida, Rui M.; Hirsch, Lionel; Toupance, Thierry; Ravaine, Serge

    2016-09-01

    The photoconversion efficiency of dye sensitized solar cells can be enhanced by the incorporation of light management nanostructures such as photonic crystals. Here, we present a facile route to incorporate titania inverse opals into solid state dye sensitized solar cells and report photoconversion efficiency enhancements of up to 56% compared with a model system without the inverse opal. Our approach is based on the precise design of titania inverse opals with a predetermined thickness that can be controlled at the individual layer level. By choosing an inverse opal exhibiting a photonic bandgap which overlaps the absorption bands of the dye, our results show that there is an optimal thickness of the inverse opal structure for maximum efficiency enhancement of the cell. This is the first experimental proof that the thickness of a titania inverse opal plays a pivotal role in cell efficiency enhancement in solid state dye sensitized solar cells.

  10. Artificial evolution of coumarin dyes for dye sensitized solar cells.

    PubMed

    Venkatraman, Vishwesh; Abburu, Sailesh; Alsberg, Bjørn Kåre

    2015-11-07

    The design and discovery of novel molecular structures with optimal properties has been an ongoing effort for materials scientists. This field has in general been dominated by experiment driven trial-and-error approaches that are often expensive and time-consuming. Here, we investigate if a de novo computational design methodology can be applied to the design of coumarin-based dye sensitizers with improved properties for use in Grätzel solar cells. To address the issue of synthetic accessibility of the designed compounds, a fragment-based assembly is employed, wherein the combination of chemical motifs (derived from the existing databases of structures) is carried out with respect to user-adaptable set of rules. Rather than using computationally intensive density functional theory (DFT)/ab initio methods to screen candidate dyes, we employ quantitative structure-property relationship (QSPR) models (calibrated from empirical data) for rapid estimation of the property of interest, which in this case is the product of short circuit current (Jsc) and open circuit voltage (Voc). Since QSPR models have limited validity, pre-determined applicability domain criteria are used to prevent unacceptable extrapolation. DFT analysis of the top-ranked structures provides supporting evidence of their potential for dye sensitized solar cell applications.

  11. Adaptation for improving lifetime of dye laser using coumarin dyes

    SciTech Connect

    Fletcher, A.N.

    1984-10-23

    The effective lasing lifetime of laser dyes including coumarin dyes are significantly extended by the use of an inert cover gas for the laser dye solution such as argon in combination with the employment of a glass filter such as Pyrex disposed between the pumping flash lamp and the dye laser cavity capable of absorbing electromagnetic radiation of about 300 nanometers or shorter wavelength.

  12. Kinetics of sonophotocatalytic degradation of anionic dyes with Nano-TiO2.

    PubMed

    Vinu, R; Madras, Giridhar

    2009-01-15

    The current research work focuses on the combination of photocatalytic and sonocatalytic (sonophotocatalytic) degradation of anionic dyes, viz., Orange G, Remazol Brilliant Blue R, Alizarin Red S, Methyl Blue, and Indigo Carmine, with solution combustion synthesized TiO2 (CS TiO2) and commercial Degussa P-25 TiO2 (DP-25). The rate of sonophotocatalytic degradation of all the dyes and the reduction of total organic carbon was higher compared to the individual photo- and sonocatalytic processes. The effect of dissolved gases and ultrasonic intensity on the sonophotocatalytic degradation of the dyes was evaluated. A dual-pathway network mechanism of sonophotocatalytic degradation was proposed for the first time, and the rate equations were modeled using the network reduction technique. The kinetic rate coefficients of the individual steps were evaluated for all the systems by fitting the model with experimental data.

  13. Ballistic labeling with fluorescent dyes and indicators.

    PubMed

    Morgan, Joshua L; Wong, Rachel O L

    2008-04-01

    Neuronal cell labeling is fundamental to investigations of the nervous system. Labeling of cells in live or fixed tissue with dyes or ion indicators using ballistic approaches has recently been developed for the study of neuronal architecture and function. In this approach, dye-coated particles are propelled into cells by a pulse of pressurized helium. This unit provides step-by-step protocols for coating tungsten particles with fluorescent or indicator dyes and for delivering these particles into cells and tissue. The major advantage of the ballistic method of dye delivery is that large populations of neurons can be rapidly labeled within a piece of live or fixed tissue. Advantages and limitations of the approach are discussed and technical advice is provided.

  14. Thermal treatment of dyes from military munitions

    SciTech Connect

    1996-09-01

    Los Alamos National Laboratory has developed thermal treatment equipment to treat Navy smoke and dye compounds. Navy smokes were burned in the Los Alamos Controlled Air Incinerator (CAI) in the early 1980s. These test results were used in the development of a portable system consisting of a Thermal Treatment Unit (TTU), feed preparation and pumping skid, utility skid, and control trailer. This equipment was started up at Navy facilities at China Lake, CA where several destruction removal efficiency tests were completed in 1993 burning smoke compositions. The equipment was set up at the Nevada Test Site (NTS) in 1996 where tests were completed burning green Navy spotting dyes. Operating and test results from the NTS efforts resulted in clearer understanding of equipment deficiencies, dye characteristics and composition, and secondary wastes generated. Future tests, scheduled for July, 1996 will demonstrate higher bum rates, better pH measurement and control, and stack emission test results for other colored dyes.

  15. Data management system performance modeling

    NASA Technical Reports Server (NTRS)

    Kiser, Larry M.

    1993-01-01

    This paper discusses analytical techniques that have been used to gain a better understanding of the Space Station Freedom's (SSF's) Data Management System (DMS). The DMS is a complex, distributed, real-time computer system that has been redesigned numerous times. The implications of these redesigns have not been fully analyzed. This paper discusses the advantages and disadvantages for static analytical techniques such as Rate Monotonic Analysis (RMA) and also provides a rationale for dynamic modeling. Factors such as system architecture, processor utilization, bus architecture, queuing, etc. are well suited for analysis with a dynamic model. The significance of performance measures for a real-time system are discussed.

  16. Biosorption of Azo dyes by spent Rhizopus arrhizus biomass

    NASA Astrophysics Data System (ADS)

    Salvi, Neeta A.; Chattopadhyay, S.

    2016-05-01

    In the present study, spent Rhizopus arrhizus biomass was used for the removal of six azo dyes from aqueous solutions. The dye removal capacity of the biomass was evaluated by conducting batch tests as a function of contact time, biomass dosage, pH and initial dye concentrations. The pseudo-second-order kinetic model fitted well with the experimental data with correlation coefficients greater than 0.999, suggesting that chemisorptions might be the rate limiting step. The equilibrium sorption data showed good fit to the Langmuir isotherm model. Among the six dyes tested, the maximum monolayer adsorption capacity for fast red A and metanil yellow was found to be 108.8 and 128.5 mg/g, respectively. These encouraging results suggest that dead Rhizopus arrhizus biomass could be a potential biomaterial for the removal of azo dyes from aqueous dye solution.

  17. Cyanine dyes as intercalating agents: kinetic and thermodynamic studies on the DNA/Cyan40 and DNA/CCyan2 systems.

    PubMed

    Biver, Tarita; De Biasi, Angela; Secco, Fernando; Venturini, Marcella; Yarmoluk, Sergiy

    2005-07-01

    The interaction of cyanines with nucleic acids is accompanied by intense changes of their optical properties. Consequently these molecules find numerous applications in biology and medicine. Since no detailed information on the binding mechanism of DNA/cyanine systems is available, a T-jump investigation of the kinetics and equilibria of binding of the cyanines Cyan40 [3-methyl-2-(1,2,6-trimethyl-4(1H)pyridinylidenmethyl)-benzothiazolium ion] and CCyan2 [3-methyl-2-[2-methyl-3-(3-methyl-2(3H)-benzothiazolylidene)-1-propenyl]-benzothiazolium ion] with CT-DNA is performed at 25 degrees C, pH 7 and various ionic strengths. Bathochromic shifts of the dye absorption band upon DNA addition, polymer melting point displacement (DeltaT = 8-10 degrees C), site size determination (n = 2), and stepwise kinetics concur in suggesting that the investigated cyanines bind to CT-DNA primary by intercalation. Measurements with poly(dA-dT).poly(dA-dT) and poly(dG-dC).poly(dG-dC) reveal fair selectivity of CCyan2 toward G-C basepairs. T-jump experiments show two kinetic effects for both systems. The binding process is discussed in terms of the sequence D + S left arrow over right arrow D,S left arrow over right arrow DS(I) left arrow over right arrow DS(II), which leads first to fast formation of an external complex D,S and then to a partially intercalated complex DS(I) which, in turn, converts to DS(II), a more stable intercalate. Absorption spectra reveal that both dyes tend to self-aggregate; the kinetics of CCyan2 self-aggregation is studied by T-jump relaxation and the results are interpreted in terms of dimer formation.

  18. Evaluation of anaerobic sludge volume for improving azo dye decolorization in a hybrid anaerobic reactor with built-in bioelectrochemical system.

    PubMed

    Cui, Min-Hua; Cui, Dan; Gao, Lei; Wang, Ai-Jie; Cheng, Hao-Yi

    2017-02-01

    A hybrid anaerobic reactor with built-in bioelectrochemical system (BES) has been verified for efficiently treating mixed azo dye wastewater, yet still facing many challenges, such as uncertain reactor construction and insufficient electron donors. In this study, an up-flow hybrid anaerobic reactor with built-in BES was developed for acid orange 7 (AO7) containing wastewater treatment. Cathode and real domestic wastewater both served as electron donor for driving azo dye decolorization. The decolorization efficiency (DE) of AO7 (200 mg/L) in the hybrid reactor was 80.34 ± 2.11% with volume ratio between anaerobic sludge and cathode (VRslu:cat) of 0.5:1 and hydraulic retention time (HRT) of 6 h, which was 15.79% higher than that in BES without sludge zone. DE was improved to 86.02 ± 1.49% with VRslu:cat increased to 1:1. Further increase in the VRslu:cat to 1.5:1 and 2:1, chemical oxygen demand (COD) removal efficiency was continuously improved to 28.78 ± 1.96 and 32.19 ± 0.62%, but there was no obvious DE elevation (slightly increased to 87.62 ± 2.50 and 90.13 ± 3.10%). BES presented efficient electron utilization, the electron usage ratios (EURs) in which fluctuated between 11.02 and 13.06 mol e(-)/mol AO7. It was less than half of that in sludge zone of 24.73-32.06 mol e(-)/mol AO7. The present work optimized the volume ratio between anaerobic sludge and cathode that would be meaningful for the practical application of this hybrid system.

  19. Poly(methylmethacrylate) grafted chitosan: An efficient adsorbent for anionic azo dyes.

    PubMed

    Singh, V; Sharma, A K; Tripathi, D N; Sanghi, R

    2009-01-30

    Present study reports on peroxydisulfate/ascorbic acid initiated synthesis of Chitosan-graft-poly(methylmethacrylate) (Ch-g-PMMA) and its characterization by FTIR, XRD and (13)C NMR. The copolymer remained water insoluble even under highly acidic conditions and was evaluated to be an efficient adsorbent for the three anionic azo dyes (Procion Yellow MX, Remazol Brilliant Violet and Reactive Blue H5G) over a wide pH range of 4-10 being most at pH 7. The adsorbent was also found efficient in decolorizing the textile industry wastewater and was much more efficient than the parent chitosan. Equilibrium sorption experiments were carried out at different pH and initial dye concentration values. The experimental equilibrium data for each adsorbent-dye system were successfully fitted to the Langmuir and Freundlich sorption isotherms. Based on Langmuir model Q(max) for yellow, violet and blue dyes was 250, 357 and 178, respectively. Thermodynamic parameters of the adsorption processes such as DeltaG degrees , DeltaH degrees , and DeltaS degrees were calculated. The negative values of free energy reflected the spontaneous nature of adsorption. The adsorption kinetic data of all the three dyes could be well represented by pseudo-second-order model with the correlation coefficients (R(2)) being 0.9922, 0.9997 and 0.9862, for direct yellow, reactive violet and blue dye, respectively with rate constants 0.91 x 10(-4), 1.82 x 10(-4) and 1.05 x 10(-4) g mg(-1)min(-1), respectively. At pH 7, parent chitosan also showed pseudo-second-order kinetics. The temperature dependence of dye uptake and the pseudo-second-order kinetics of the adsorption indicated that chemisorption is the rate-limiting step that controls the process.

  20. Kinetics and thermodynamics of textile dye adsorption from aqueous solutions using babassu coconut mesocarp.

    PubMed

    Vieira, Adriana P; Santana, Sirlane A A; Bezerra, Cícero W B; Silva, Hildo A S; Chaves, José A P; de Melo, Júlio C P; da Silva Filho, Edson C; Airoldi, Claudio

    2009-07-30

    Extracted babassu coconut (Orbignya speciosa) mesocarp (BCM) was applied as a biosorbent for aqueous Blue Remazol R160 (BR 160), Rubi S2G (R S2G), Red Remazol 5R (RR 5), Violet Remazol 5R (VR 5) and Indanthrene Olive Green (IOG) dye solutions. The natural sorbent was processed batchwise while varying several system parameters such as stirring time, pH and temperature. The interactions were assayed with respect to both pseudo-first-order and second-order reaction kinetics, with the latter the more suitable kinetic model. The maximum adsorption was obtained at pH 1.0 for all dyes due to available anionic groups attached to the structures, which can be justified by pH(pzc) 6.7 for the biosorbent BCM. The ability of babassu coconut mesocarp to adsorb dyes gave the order R S2G>VR 5>BR 160>IOG>RR 5, which data were best fit to Freundlich model, but did not well-adjusted for all dyes. The dye/biopolymer interactions at the solid/liquid interface are all spontaneous as given by free Gibbs energy, with exothermic enthalpic values of -26.1, -15.8, -17.8, -15.8 and -23.7 kJ mol(-1) for BR 160, R S2G, RR 5, IOG and VR 5, respectively. In spite of the negative entropic values contribution, the set of thermodynamic data is favorable for all dyes removal. However, the results pointed to the effectiveness of the mesocarp of babassu coconut as a biosorbent for removing textile dyes from aqueous solutions.

  1. Adsorption Capability of Cationic Dyes (Methylene Blue and Crystal Violet) onto Poly-γ-glutamic Acid.

    PubMed

    Ogata, Fumihiko; Nagai, Noriaki; Kawasaki, Naohito

    2017-01-01

    In this study, the adsorption capability of cationic dyes, which were methylene blue and crystal violet, by poly-γ-glutamic acid (PGA) in a single or binary solution system was investigated. The effect of the molecular weight of PGA, initial dye concentration, solution pH, and temperature on the adsorption of dyes was evaluated. The adsorption mechanism of dyes onto PGA was the interaction between -COOH group on the PGA surface and the polarity groups of dyes. These results indicated that PGA is useful for removal of dyes and cationic organic compounds from a single or binary solution system.

  2. Adsorption of dyes using peat: equilibrium and kinetic studies.

    PubMed

    Sepúlveda, L; Fernández, K; Contreras, E; Palma, C

    2004-09-01

    In recent years, adsorption has been accepted as one of the most appropriate processes for decolorization of wastewaters. This paper presents experimental results on application of peat for removal of structurally diverse dyes (azo, oxazine, triphenylmethane, thiazine and others) with emphasis on relevant factors such as the adsorbate-adsorbent chemical properties and chemical interaction as well as adsorption conditions. The equilibrium experimental results were fitted to Langmuir and Freundlich isotherms to obtain the characteristic parameters of each model. According to the evaluation using the Langmuir equation, the maximum sorption capacity of basic dyes at 22 degrees C was 667 (mg g(-1)) for Basic Blue 24, 526 (mg g(-1)) for Basic Green 4 and 714 (mg g(-1)) for Basic Violet 4. On the other hand for Acid Black 1 it was only 25 (mg g(-1)). Batch kinetics studies were undertaken and the data evaluated in compliance with chemical sorption mechanisms. For all of the systems studied the pseudo-second order model provided the best correlation of the kinetic experimental data. A film-pore double resistance diffusion model for mass transfer has also been used in this study to determine the effective diffusivity, Deff, for the adsorption of basic dyes in to peat.

  3. Coastal Modeling System Advanced Topics

    DTIC Science & Technology

    2012-06-18

    is the CMS? Integrated wave, current, and morphology change model in the Surface-water Modeling System (SMS). Why CMS? Operational at 10...Coupled with spectral wave model (CMS-Wave)  Wave-current interactions  Inline sediment transport and morphology change  Non-equilibrium...Easy to setup  Telescoping grid: Efficient and flexible  Solver options  Implicit: Tidal flow, long-term morphology change. ~10 min

  4. Modeling of Embedded Human Systems

    DTIC Science & Technology

    2013-07-01

    reduces to solving an initial value HJ PDE. Let the system dynamics be given by ẋ = f(x, u), where f is bounded and Lipschitz continuous in x. Choose the...Sprinkle, “Synthesizing executable simulations from structural models of component- based systems,” Electronic Communications of the European Association

  5. Photovoltaic Systems Modeling and Analysis

    NASA Astrophysics Data System (ADS)

    Ali, Mir Shahed

    2010-11-01

    This thesis deals with the implementation of generalized photovoltaic model and integration of the same with 7-bus electrical utility system to evaluate the impact that the photovoltaic generator have on the utility system. Among all the impacts that the photovoltaic generator have on the utility system, voltage rise of the power distribution line at the position where the Photovoltaic generator is connected due to reverse power flow from the photovoltaic model has been one of the major problem. Therefore, this thesis proposes the steady-state simulations to evaluate the effectiveness of battery-integrated PV system on avoiding the over voltage problem. Further, fault analysis is done to study the effect of the PV model on the utility network during faults and it is deduced that the impact of the PV model on the utility system voltage during faults is nominal. The photovoltaic model/generator and the 7-bus utility system is developed using Matlab/Simulink software package. The developed photovoltaic model can be represented as PV cell, module or an array. The model is developed with icons that are easy to understand. The developed model takes into consideration cell's working temperature, amount of sunlight (irradiance) available, voltage of the circuit when the circuit is open and current of the circuit when it is shorted. The developed Photovoltaic model is then integrated with a Li-ion battery, over here battery serves two purposes first it will store the excess power from the Photovoltaic generator if any, during the day time and in night the battery acts as an generator and deliver the power to the utility or connected load with the help of an invertors.

  6. Optimization of Orange G dye adsorption by activated carbon of Thespesia populnea pods using response surface methodology.

    PubMed

    Arulkumar, M; Sathishkumar, P; Palvannan, T

    2011-02-15

    Thespesia populnea is a large tree found in the tropical regions and coastal forests of India. Its pods were used as a raw material for the preparation of activated carbon. The prepared activated carbon was used for the adsorptive removal of Orange G dye from aqueous system. The effects of various parameters such as agitation time, initial dye concentration and adsorbent dosage were studied using response surface methodology (RSM). RSM results show that 0.54 g of activated carbon was required for the maximum adsorption of Orange G dye (17.6 mg L(-1)) within a time period of 4.03 h. Adsorption data were modeled using Freundlich and Langmuir adsorption isotherms. The adsorption of Orange G dye by activated carbon obeyed both Fruendlich and Langmuir isotherm. Adsorption kinetic data were tested using pseudo-zero, first, second-order and intraparticle diffusion models. Kinetic studies revealed that the adsorption followed pseudo-second-order reaction with regard to the intraparticle diffusion. FTIR spectral result indicated all the functional group except primary amines (3417 cm(-1)) and CN (1618 cm(-1)) were involved in the adsorption process. XRD data showed that Orange G dye adsorbed activated carbon might not induce the bulk phase changes. SEM results showed that the surface of the activated carbon was turned from dark to light color after dye adsorption.

  7. Detoxification of azo dyes in the context of environmental processes.

    PubMed

    Rawat, Deepak; Mishra, Vandana; Sharma, Radhey Shyam

    2016-07-01

    Azo dyes account for >70% of the global industrial demand (∼9 million tons). Owing to their genotoxic/carcinogenic potential, the annual disposal of ∼4,500,000 tons of dyes and/or degraded products is an environmental and socio-economic concern. In comparison to physico-chemical methods, microbe-mediated dye degradation is considered to be low-input, cost-effective and environmentally-safe. However, under different environmental conditions, interactions of chemically diverse dyes with metabolically diverse microbes produce metabolites of varying toxicity. In addition, majority of studies on microbial dye-degradation focus on decolorization with least attention towards detoxification. Therefore, the environmental significance of microbial dye detoxification research of past >3 decades is critically evaluated with reference to dye structure and the possible influence of microbial interactions in different environments. In the absence of ecosystem-based studies, the results of laboratory-based studies on dye degradation, metabolite production and their genotoxic impact on model organisms are used to predict the possible fate and consequences of azo dyes/metabolites in the environment. In such studies, the predominance of fewer numbers of toxicological assays that too at lower levels of biological organization (molecular/cellular/organismic) suggests its limited ecological significance. Based on critical evaluation of these studies the recommendations on inclusion of multilevel approach (assessment at multiple levels of biological organization), multispecies microcosm approach and native species approach in conjunction with identification of dye metabolites have been made for future studies. Such studies will bridge the gap between the fundamental knowledge on dye-microbe-environment interactions and its application to combat dye-induced environmental toxicity. Thus an environmental perspective on dye toxicity in the background of dye structure and effects of

  8. Degradation of textile dyes by cyanobacteria.

    PubMed

    Dellamatrice, Priscila Maria; Silva-Stenico, Maria Estela; Moraes, Luiz Alberto Beraldo de; Fiore, Marli Fátima; Monteiro, Regina Teresa Rosim

    Dyes are recalcitrant compounds that resist conventional biological treatments. The degradation of three textile dyes (Indigo, RBBR and Sulphur Black), and the dye-containing liquid effluent and solid waste from the Municipal Treatment Station, Americana, São Paulo, Brazil, by the cyanobacteria Anabaena flos-aquae UTCC64, Phormidium autumnale UTEX1580 and Synechococcus sp. PCC7942 was evaluated. The dye degradation efficiency of the cyanobacteria was compared with anaerobic and anaerobic-aerobic systems in terms of discolouration and toxicity evaluations. The discoloration was evaluated by absorption spectroscopy. Toxicity was measured using the organisms Hydra attenuata, the alga Selenastrum capricornutum and lettuce seeds. The three cyanobacteria showed the potential to remediate textile effluent by removing the colour and reducing the toxicity. However, the growth of cyanobacteria on sludge was slow and discoloration was not efficient. The cyanobacteria P. autumnale UTEX1580 was the only strain that completely degraded the indigo dye. An evaluation of the mutagenicity potential was performed by use of the micronucleus assay using Allium sp. No mutagenicity was observed after the treatment. Two metabolites were produced during the degradation, anthranilic acid and isatin, but toxicity did not increase after the treatment. The cyanobacteria showed the ability to degrade the dyes present in a textile effluent; therefore, they can be used in a tertiary treatment of effluents with recalcitrant compounds.

  9. Kinetic Modeling of Biological Systems

    PubMed Central

    Petzold, Linda; Pettigrew, Michel F.

    2010-01-01

    The dynamics of how the constituent components of a natural system interact defines the spatio-temporal response of the system to stimuli. Modeling the kinetics of the processes that represent a biophysical system has long been pursued with the aim of improving our understanding of the studied system. Due to the unique properties of biological systems, in addition to the usual difficulties faced in modeling the dynamics of physical or chemical systems, biological simulations encounter difficulties that result from intrinsic multiscale and stochastic nature of the biological processes. This chapter discusses the implications for simulation of models involving interacting species with very low copy numbers, which often occur in biological systems and give rise to significant relative fluctuations. The conditions necessitating the use of stochastic kinetic simulation methods and the mathematical foundations of the stochastic simulation algorithms are presented. How the well-organized structural hierarchies often seen in biological systems can lead to multiscale problems, and possible ways to address the encountered computational difficulties are discussed. We present the details of the existing kinetic simulation methods, and discuss their strengths and shortcomings. A list of the publicly available kinetic simulation tools and our reflections for future prospects are also provided. PMID:19381542

  10. Energy transfer versus charge separation in hybrid systems of semiconductor quantum dots and Ru-dyes as potential co-sensitizers of TiO2-based solar cells

    NASA Astrophysics Data System (ADS)

    Giménez, Sixto; Rogach, Andrey L.; Lutich, Andrey A.; Gross, Dieter; Poeschl, Andreas; Susha, Andrei S.; Mora-Seró, Ivan; Lana-Villarreal, Teresa; Bisquert, Juan

    2011-07-01

    Hybrid structures of colloidal quantum dots (QDs) with Ru-dyes have been studied as candidates for panchromatic sensitizers for TiO2-based solar cells. Steady-state and time resolved photoluminescence spectroscopy and photocurrent measurements have been employed to identify the prevailing transfer mechanisms for photogenerated excitons between CdSe QDs capped with a traditional bulky organic ligand trioctylphosphine and Ru-dyes (N3 or Ru505) deposited onto inert glass or mesoporous TiO2 substrates. The type II energy level alignment between the QDs and both N3 and Ru505 offers a possibility for the directional charge separation, with electrons transferred to the QDs and holes to the dye. This scenario is indeed valid for the QD/Ru505 and TiO2/QD/Ru505 hybrid systems, with the negligible spectral overlap between the emission of the QDs and the absorption of the Ru505 dye. For the QD/N3 and TiO2/QD/N3 hybrid systems, the spectral overlap favors the longer range energy transfer from the QDs to N3, independently of the presence of the electron acceptor TiO2.

  11. Modified triphenylamine-dicyanovinyl-based donor-acceptor dyes with enhanced power conversion efficiency of p-type dye-sensitized solar cells.

    PubMed

    Zhu, Linna; Yang, Hongbin; Zhong, Cheng; Li, Chang Ming

    2012-12-01

    To dye for: Two new dyes are synthesized by structural modifications of one of the best dyes for NiO p-type dye-sensitized solar cells, which is based on a triphenylamine-dicyanovinyl donor-acceptor system. An additional thiophene unit near the anchoring group can greatly retard charge recombination while enhancing the absorption coefficient to significantly improve the photoconversion efficiency by 50%.

  12. Stirling Engine Dynamic System Modeling

    NASA Technical Reports Server (NTRS)

    Nakis, Christopher G.

    2004-01-01

    The Thermo-Mechanical systems branch at the Glenn Research Center focuses a large amount time on Stirling engines. These engines will be used on missions where solar power is inefficient, especially in deep space. I work with Tim Regan and Ed Lewandowski who are currently developing and validating a mathematical model for the Stirling engines. This model incorporates all aspects of the system including, mechanical, electrical and thermodynamic components. Modeling is done through Simplorer, a program capable of running simulations of the model. Once created and then proven to be accurate, a model is used for developing new ideas for engine design. My largest specific project involves varying key parameters in the model and quantifying the results. This can all be done relatively trouble-free with the help of Simplorer. Once the model is complete, Simplorer will do all the necessary calculations. The more complicated part of this project is determining which parameters to vary. Finding key parameters depends on the potential for a value to be independently altered in the design. For example, a change in one dimension may lead to a proportional change to the rest of the model, and no real progress is made. Also, the ability for a changed value to have a substantial impact on the outputs of the system is important. Results will be condensed into graphs and tables with the purpose of better communication and understanding of the data. With the changing of these parameters, a more optimal design can be created without having to purchase or build any models. Also, hours and hours of results can be simulated in minutes. In the long run, using mathematical models can save time and money. Along with this project, I have many other smaller assignments throughout the summer. My main goal is to assist in the processes of model development, validation and testing.

  13. Effect of some process parameters in enzymatic dyeing of wool.

    PubMed

    Tzanov, Tzanko; Silva, Carla Joana; Zille, Andrea; Oliveira, Jovita; Cavaco-Paulo, Artur

    2003-10-01

    This article reports on the dyeing of wool using an enzymatic system comprising laccase; dye precursor, 2,5-diaminobenzenesulfonic acid; and dye modifiers, catechol and resorcinol. Enzymatic dyeing was performed as a batchwise process at the temperature and pH of maximum enzyme activity. The effects of the process variables reaction time, enzyme, and modifier concentration on fabric color were studied, according to an appropriate experimental design. Different hues and depths of shades could be achieved by varying the concentration of the modifiers and the time of laccase treatment. The duration of the enzymatic reaction appeared to be the most important factor in the dyeing process. Thus, the dyeing process, performed at low temperature and mild pH, was advantageous in terms of reduced enzyme and chemical dosage.

  14. Multi-scale biomarker evaluation of the toxicity of a commercial azo dye (Disperse Red 1) in an animal model, the freshwater cnidarian Hydra attenuata.

    PubMed

    de Jong, Laetitia; Pech, Nicolas; de Aragão Umbuzeiro, Gisela; Moreau, Xavier

    2016-06-01

    Acute (24 h, 48 h, 72 h) and chronic (7 days) tests have been performed to evaluate the effects of the commercial azo dye Disperse Red 1 (DR1) using various biomarkers in the freshwater invertebrate Hydra attenuata. Morphological changes have been selected to calculate ecotoxicological thresholds for sublethal and lethal DR1 concentrations. A multinomial logistic model showed that the probability of each morphological stage occurrence was function of concentration, time and interaction between both. Results of oxidative balance parameter measurements (72 h and 7 days) suggest that polyps set up defense mechanisms to limit lipid peroxidation caused by DR1. DR1 exposure at hormetic concentrations induces increase of asexual reproductive rates. This result suggests (1) an impact on the fitness-related phenotypical traits and (2) trade-offs between reproduction and maintenance to allow the population to survive harsher conditions. Changes in serotonin immuno-labeling in polyps showing alterations in feeding behavior suggest that chronic DR1 exposure impaired neuronal processes related to ingesting behavior in H. attenuata. This ecotoxicity study sheds light on the possible serotonin function in Hydra model and reports for the first time that serotonin could play a significant role in feeding behavior. This study used a multi-scale biomarker approach investigating biochemical, morphological, reproductive and behavioral endpoints in Hydra attenuata. This organism is proposed for a pertinent animal model to assess ecotoxicological impact of pollutant mixtures in freshwater environment.

  15. Treatment of dye wastewater with permanganate oxidation and in situ formed manganese dioxides adsorption: cation blue as model pollutant.

    PubMed

    Liu, Ruiping; Liu, Huijuan; Zhao, Xu; Qu, Jiuhui; Zhang, Ran

    2010-04-15

    This study investigated the process of potassium permanganate (KMnO(4)) oxidation and in situ formed hydrous manganese dioxides (deltaMnO(2)) (i.e., KMnO(4) oxidation and deltaMnO(2) adsorption) for the treatment of dye wastewater. The effectiveness of decolorization, removing dissolved organic carbon (DOC), and increasing biodegradable oxygen demand (BOD) were compared among these processes of KMnO(4) oxidation, deltaMnO(2) adsorption, and KMnO(4) oxidation and deltaMnO(2) adsorption. DeltaMnO(2) adsorption contributed to the maximum DOC removal of 65.0%, but exhibited limited capabilities of decolorizing and increasing biodegradability. KMnO(4) oxidation alone at pH 0.5 showed satisfactory decrease of UV-vis absorption peaks, and the maximum BOD(5)/DOC value of 1.67 was achieved. Unfortunately, the DOC removal was as low as 27.4%. Additionally, the great amount of acid for pH adjustment and the much too low pH levels limited its application in practice. KMnO(4) oxidation and deltaMnO(2) adsorption at pH 2.0 was the best strategy prior to biological process, in balancing the objectives of decolorization, DOC removal, and BOD increase. The optimum ratio of KMnO(4) dosage to X-GRL concentration (R(KMnO(4)/X-GRL)) was determined to be 2.5, at which KMnO(4) oxidation and deltaMnO(2) adsorption contributed to the maximal DOC removal of 53.4%. Additionally, the optimum pH for X-GRL treatment was observed to be near 3.0.

  16. The adsorption of basic dye (Astrazon Blue FGRL) from aqueous solutions onto sepiolite, fly ash and apricot shell activated carbon: kinetic and equilibrium studies.

    PubMed

    Karagozoglu, B; Tasdemir, M; Demirbas, E; Kobya, M

    2007-08-17

    In this study, sepiolite, fly ash and apricot stone activated carbon (ASAC) were used as adsorbents for the investigation of the adsorption kinetics, isotherms and thermodynamic parameters of the basic dye (Astrazon Blue FGRL) from aqueous solutions at various concentrations (100-300 mg/L), adsorbent doses (3-12 g/L) and temperatures (303-323 K). The result showed that the adsorption capacity of the dye increased with increasing initial dye concentration, adsorbent dose and temperature. Three kinetic models, the pseudo-first-order, second-order, intraparticle diffusion, were used to predict the adsorption rate constants. The kinetics of adsorption of the basic dye followed pseudo-second-order kinetics. Equations were developed using the pseudo-second-order model which predicts the amount of the basic dye adsorbed at any contact time, initial dye concentration and adsorbent dose within the given range accurately. The adsorption equilibrium data obeyed Langmuir isotherm. The adsorption capacities (Q0) calculated from the Langmuir isotherm were 181.5 mg/g for ASAC, 155.5 mg/g for sepiolite and 128.2 mg/g for fly ash at 303 K. Thermodynamical parameters were also evaluated for the dye-adsorbent systems and revealed that the adsorption process was endothermic in nature.

  17. Kinetics of adsorption of dyes from aqueous solution using activated carbon prepared from waste apricot.

    PubMed

    Onal, Yunus

    2006-10-11

    Adsorbent (WA11Zn5) has been prepared from waste apricot by chemical activation with ZnCl(2). Pore properties of the activated carbon such as BET surface area, pore volume, pore size distribution, and pore diameter were characterized by N(2) adsorption and DFT plus software. Adsorption of three dyes, namely, Methylene Blue (MB), Malachite Green (MG), Crystal Violet (CV), onto activated carbon in aqueous solution was studied in a batch system with respect to contact time, temperature. The kinetics of adsorption of MB, MG and CV have been discussed using six kinetic models, i.e., the pseudo-first-order model, the pseudo-second-order model, the Elovich equation, the intraparticle diffusion model, the Bangham equation, the modified Freundlich equation. Kinetic parameters and correlation coefficients were determined. It was shown that the second-order kinetic equation could describe the adsorption kinetics for three dyes. The dyes uptake process was found to be controlled by external mass transfer at earlier stages (before 5 min) and by intraparticle diffusion at later stages (after 5 min). Thermodynamic parameters, such as DeltaG, DeltaH and DeltaS, have been calculated by using the thermodynamic equilibrium coefficient obtained at different temperatures and concentrations. The thermodynamics of dyes-WA11Zn5 system indicates endothermic process.

  18. Dichroic behavior of the absorbance signals from dyes NK2367 and WW375 in skeletal muscle fibers

    PubMed Central

    1984-01-01

    Absorbance signals were recorded from voltage-clamped single muscle fibers stained with the nonpenetrating potentiometric dyes NK2367 and WW375 and illuminated with quasimonochromatic light from 560 to 800 nm, linearly polarized either parallel (0 degree) or perpendicular (90 degrees) to the fiber long axis. The signals from both dyes depend strongly on the incident polarization. At any wavelength and/or polarization condition, the total absorbance signal is a superposition of the same two signal components previously identified with unpolarized light (Heiny, J. A., and J. Vergara, 1982, J. Gen. Physiol., 80:203)--namely, a fast step signal from the voltage-clamped surface membrane and a signal reflecting the slower T-system potential changes. The 0 degree and 90 degrees spectra of both membranes have similar positive and negative absorbance peaks (720 and 670 nm, respectively, for dye NK2367; 740 and 700 nm for dye WW375); in addition, they have the same dichroic maxima (670 for NK2367; 700 for WW375). However, for the surface membrane, the 0 degrees spectra are everywhere more positive than the 90 degrees spectra, whereas the reverse is true for the T-system, which results in a dichroism of opposite sign for the two membranes. These spectral characteristics were analyzed using a general model for the potential-dependent response of an absorbing dye (Tasaki, I., and A. Warashina, 1976, Photochem. Photobiol., 24:191), which takes into account both the dye response and the membrane geometries. They are consistent with the proposal that the dye responds via a common mechanism in both membranes that consists of a dye reorientation and a change in the absorption maxima. PMID:6334719

  19. Formic acid enhanced effective degradation of methyl orange dye in aqueous solutions under UV-Vis irradiation.

    PubMed

    Wang, Jingjing; Bai, Renbi

    2016-09-15

    Developing efficient technologies to treat recalcitrant organic dye wastewater has long been of great research and practical interest. In this study, a small molecule, formic acid (FA), was applied as a process enhancer for the degradation of methyl orange (MO) dye as a model recalcitrant organic pollutant in aqueous solutions under the condition of UV-Vis light irradiation and air aeration at the ambient temperature of 25 °C. It was found that the decolouration of the dye solutions can be rapidly achieved, reducing the time, for example, from around 17.6 h without FA to mostly about less than 2 h with the presence of FA. The mineralization rate of MO dye reached as high as 81.8% in 1.5 h in the case of initial MO dye concentration at 25 mg L(-1), which is in contrast to nearly no mineralization of the MO dye for a similar system without the FA added. The study revealed that the generation of the H2O2 species in the system was enhanced and the produced OH radicals effectively contributed to the degradation of the MO dye. Process parameters such as the initial concentration of MO dye, FA dosage and solution pH were all found to have some effect on the degradation efficiency under the same condition of UV-Vis light irradiation and air aeration. The MO dye degradation performance was found to follow a first-order reaction rate to the MO dye concentration in most cases and there existed a positive correlation between the reaction rate constant and the initial FA concentration. Compared to the traditional H2O2/UV-Vis oxidation system, the use of FA as a process-enhancing agent can have the advantages of low cost, easy availability, and safe to use. The study hence demonstrates a promising approach to use a readily available small molecule of FA to enhance the degradation of recalcitrant organic pollutants, such as MO dye, especially for their pre-treatment.

  20. Generalized Environment for Modeling Systems

    SciTech Connect

    2012-02-07

    -04) created at INL to work inside SharePoint. The GUI tool links slider bars and drop downs to specific inputs and output of the ModelCenter model that is executable from SharePoint. The modeler also creates in SAS, dashboards, graphs and tables that are exposed by links and SAS and ModelCenter Web Parts into the SharePoint system. The user can then log into SharePoint, move slider bars and select drop down lists to configure the model parameters, click to run the model, and then view the output results that are based on their particular input choices. The main point is that GEMS eliminates the need for a programmer to connect and create the web artifacts necessary to implement and deliver an executable model or decision aid to customers.

  1. Energy transfer between a biological labelling dye and gold nanorods

    NASA Astrophysics Data System (ADS)

    Racknor, Chris; Singh, Mahi R.; Zhang, Yinan; Birch, David J. S.; Chen, Yu

    2014-03-01

    We have demonstrated energy transfer between a biological labelling dye (Alexa Fluor 405) and gold nanorods experimentally and theoretically. The fluorescence lifetime imaging microscopy and density matrix method are used to study a hybrid system of dye and nanorods under one- and two-photon excitations. Energy transfer between dye and nanorods via the dipole-dipole interaction is found to cause a decrease in the fluorescence lifetime change. Enhanced energy transfer from dye to nanorods is measured in the presence of an increased density of nanorods. This study has potential applications in fluorescence lifetime-based intra-cellular sensing of bio-analytes as well as nuclear targeting cancer therapy.

  2. Design of Far-Red Sensitizing Squaraine Dyes Aiming Towards the Fine Tuning of Dye Molecular Structure.

    PubMed

    Morimoto, Takuya; Fujikawa, Naotaka; Ogomi, Yuhei; Pandey, Shyam S; Ma, Tingli; Hayase, Shuzi

    2016-04-01

    Model squaraine dyes having sharp and narrow absorptions mainly in the far-red wavelength region has been logically designed, synthesized and used for their application as sensitizer in the dyesensitized solar cells (DSSC). In order to have fine control on energetics, dyes having same mother core and alkyl chain length varying only in molecular symmetry and position of substituent were designed. It has been found that even keeping all other structural factor constant, only positional variation of substituent leads to not only in the variation of energetics by 0.1 eV but affects the photovoltaic characteristics also. Optimum concentration of dye de-aggregating agent was found to be 100 times with respect to the sensitizing dye concentration. Amongst dyes utilized in this work best performance was obtained for unsymmetrical dye SQ-40 giving a photoconversion efficiency of 4.01% under simulated solar irradiation at global AM 1.5.

  3. Design of hybrid nanoheterostructure systems for enhanced quantum and solar conversion efficiencies in dye-sensitized solar cells

    SciTech Connect

    Kılıç, Bayram E-mail: kbayramkilic@gmail.com; Telli, Hakan; Başaran, Ali; Pirge, Gursev; Tüzemen, Sebahattin

    2015-04-07

    Dye sensitized solar cells (DSSCs) with an innovative design involving controlled-morphology vertically aligned (VA) ZnO nanowires within mesoporous TiO{sub 2} structures with ultrahigh surface area for implementation as photoanodes are herein reported. Although TiO{sub 2} nanostructures exhibit excellent power conversion efficiency, the electron transport rate is low owing to low electron mobility. To overcome this, ZnO nanowires with high electron mobility have been investigated as potential candidates for photoanodes. However, the power conversion efficiency of ZnO nanowires is still lower than that of TiO{sub 2} owing to their low internal surface area. Consequently, in this work, vertical growth of ZnO nanowires within mesoporous TiO{sub 2} structures is carried out to increase their solar power conversion efficiency. The photovoltaic performance of solar cells using ZnO nanowires, mesoporous TiO{sub 2}, and TiO{sub 2}/ZnO hybrid structures are compared. The VA TiO{sub 2}/ZnO hybrid structures are found to provide direct electron transfer compared with the tortuous pathway of zero-dimensional nanostructures, resulting in an increased conversion efficiency. It is demonstrated that the light scattering of the photoanode film is increased and electron recombination is decreased when an appropriate amount of mesoporous TiO{sub 2} is used as a substrate for ZnO nanowires. The DSSC fabricated with the TiO{sub 2}/ZnO hybrid photoanode prepared with 15.8 wt. % TiO{sub 2} showed the highest conversion efficiency of 7.30%, approximately 5%, 18%, and 40% higher than that of DSSCs fabricated with 3.99 wt. % TiO{sub 2}, pure TiO{sub 2}, and pure ZnO photoanodes, respectively.

  4. Design of hybrid nanoheterostructure systems for enhanced quantum and solar conversion efficiencies in dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Kılıç, Bayram; Telli, Hakan; Tüzemen, Sebahattin; Başaran, Ali; Pirge, Gursev

    2015-04-01

    Dye sensitized solar cells (DSSCs) with an innovative design involving controlled-morphology vertically aligned (VA) ZnO nanowires within mesoporous TiO2 structures with ultrahigh surface area for implementation as photoanodes are herein reported. Although TiO2 nanostructures exhibit excellent power conversion efficiency, the electron transport rate is low owing to low electron mobility. To overcome this, ZnO nanowires with high electron mobility have been investigated as potential candidates for photoanodes. However, the power conversion efficiency of ZnO nanowires is still lower than that of TiO2 owing to their low internal surface area. Consequently, in this work, vertical growth of ZnO nanowires within mesoporous TiO2 structures is carried out to increase their solar power conversion efficiency. The photovoltaic performance of solar cells using ZnO nanowires, mesoporous TiO2, and TiO2/ZnO hybrid structures are compared. The VA TiO2/ZnO hybrid structures are found to provide direct electron transfer compared with the tortuous pathway of zero-dimensional nanostructures, resulting in an increased conversion efficiency. It is demonstrated that the light scattering of the photoanode film is increased and electron recombination is decreased when an appropriate amount of mesoporous TiO2 is used as a substrate for ZnO nanowires. The DSSC fabricated with the TiO2/ZnO hybrid photoanode prepared with 15.8 wt. % TiO2 showed the highest conversion efficiency of 7.30%, approximately 5%, 18%, and 40% higher than that of DSSCs fabricated with 3.99 wt. % TiO2, pure TiO2, and pure ZnO photoanodes, respectively.

  5. Immobilized fluorescent dyes for sensitive pH measurements on enamel surfaces with fiber optics

    NASA Astrophysics Data System (ADS)

    Rumphorst, A.; Seeger, Stefan; Duschner, H.

    1996-01-01

    Information on the pH directly on surfaces of dental enamel is an important aspect in research on tooth decay. As an alternative to pH-electrodes our approach to the problem is the optical determination of pH by pH sensitive fluorescent dyes immobilized to tooth surfaces. In this study a model for measuring pH either on aminated cellulose substrates or on enamel (in vitro) with a fluorescein type dye is presented. The experimental realization is a fiber optic sensor with a nitrogen-pumped dye laser system and photodiode for the detection of the emitted fluorescence light. The surface pH values in the range between 4 and 7 were derived from the ratios of the excitation bands at 490 nm and 460 nm.

  6. A Simplified, Light Emitting Diode (LED) Based, Modular System to be Used for the Rapid Evaluation of Fruit and Vegetable Quality: Development and Validation on Dye Solutions

    PubMed Central

    Civelli, Raffaele; Giovenzana, Valentina; Beghi, Roberto; Naldi, Ezio; Guidetti, Riccardo; Oberti, Roberto

    2015-01-01

    NIR spectroscopy has proven to be one of the most efficient and ready to transfer tools to monitor product’s quality. Portable VIS/NIR instruments are particularly versatile and suitable for field use to monitor the ripening process or quality parameters. The aim of this work is to develop and evaluate a new simplified optoelectronic system for potential measurements on fruit and vegetables directly in the field. The development, characterization and validation of an operative prototype is discussed. LED technology was chosen for the design, and spectral acquisition at four specific wavelengths (630, 690, 750 and 850 nm) was proposed. Nevertheless, attention was given to the modularity and versatility of the system. Indeed, the possibility to change the light sources module with other wavelengths allows one to adapt the use of the same device for different foreseeable applications and objectives, e.g., ripeness evaluation, detection of particular diseases and disorders, chemical and physical property prediction, shelf life analysis, as well as for different natures of products (berry, leaf or liquid). Validation tests on blue dye water solutions have shown the capability of the system of discriminating low levels of reflectance, with a repeatability characterized by a standard deviation proportional to the measured intensity and in general limited to 2%–4%. PMID:26371002

  7. Modelling robotic systems with DADS

    NASA Technical Reports Server (NTRS)

    Churchill, L. W.; Sharf, I.

    1993-01-01

    With the appearance of general off-the-shelf software packages for the simulation of mechanical systems, modelling and simulation of mechanisms has become an easier task. The authors have recently used one such package, DADS, to model the dynamics of rigid and flexible-link robotic manipulators. In this paper, we present this overview of our learning experiences with DADS, in the hope that it will shorten the learning process for others interested in this software.

  8. Tunable models in measuring systems

    NASA Astrophysics Data System (ADS)

    Avdeev, V. P. L.; Parparov, Y. G.; Sulman, L. A.; Myshlyaev, L. P.; Polyak, A. V.

    The inclusion of tunable models in technological measuring systems, including those used in the iron and steel industry is considered. A method is proposed for the stable estimation of process parameters that consists of the anti-interference tuning of partial models of signal sources by means of robust isolation and smoothing of the informative regions of data with explicit allowance for the criteria of variability of residues and the estimates themselves.

  9. Electrochemical and optical studies of model photosynthetic systems

    SciTech Connect

    Not Available

    1992-01-15

    The objective of this research is to obtain a better understanding of the relationship between the structural organization of photosynthetic pigments and their spectroscopic and electrochemical properties. Defined model systems were studied first. These included the least ordered (solutions) through the most highly ordered (Langmuir-Blodgett (LB) monolayers and self-assembled monolayers) systems containing BChl, BPheo, and UQ. Molecules other than the photosynthetic pigments and quinones were also examined, including chromophores (i.e. surface active cyanine dyes and phtahlocyanines) an redox active compounds (methyl viologen (MV) and surfactant ferrocenes), in order to develop the techniques needed to study the photosynthetic components. Because the chlorophylls are photosensitive and labile, it was easier first to develop procedures using stable species. Three different techniques were used to characterize these model systems. These included electrochemical techniques for determining the standard oxidation and reduction potentials of the photosynthetic components as well as methods for determining the heterogeneous electron transfer rate constants for BChl and BPheo at metal electrodes (Pt and Au). Resonance Raman (RR) and surface enhanced resonance Raman (SERR) spectroscopy were used to determine the spectra of the photosynthetic pigments and model compounds. SERRS was also used to study several types of photosynthetic preparations.

  10. Stochastic Models of Polymer Systems

    DTIC Science & Technology

    2016-01-01

    algorithms for big data applications . (2) We studied stochastic dynamics of polymer systems in the mean field limit. (3) We studied noisy Hegselmann-Krause...DISTRIBUTION AVAILIBILITY STATEMENT 6. AUTHORS 7. PERFORMING ORGANIZATION NAMES AND ADDRESSES 15. SUBJECT TERMS b. ABSTRACT 2. REPORT TYPE 17. LIMITATION...Distribution Unlimited Final Report: Stochastic Models of Polymer Systems The views, opinions and/or findings contained in this report are those of the

  11. Video distribution system cost model

    NASA Technical Reports Server (NTRS)

    Gershkoff, I.; Haspert, J. K.; Morgenstern, B.

    1980-01-01

    A cost model that can be used to systematically identify the costs of procuring and operating satellite linked communications systems is described. The user defines a network configuration by specifying the location of each participating site, the interconnection requirements, and the transmission paths available for the uplink (studio to satellite), downlink (satellite to audience), and voice talkback (between audience and studio) segments of the network. The model uses this information to calculate the least expensive signal distribution path for each participating site. Cost estimates are broken downy by capital, installation, lease, operations and maintenance. The design of the model permits flexibility in specifying network and cost structure.

  12. Parametric Modeling for Fluid Systems

    NASA Technical Reports Server (NTRS)

    Pizarro, Yaritzmar Rosario; Martinez, Jonathan

    2013-01-01

    Fluid Systems involves different projects that require parametric modeling, which is a model that maintains consistent relationships between elements as is manipulated. One of these projects is the Neo Liquid Propellant Testbed, which is part of Rocket U. As part of Rocket U (Rocket University), engineers at NASA's Kennedy Space Center in Florida have the opportunity to develop critical flight skills as they design, build and launch high-powered rockets. To build the Neo testbed; hardware from the Space Shuttle Program was repurposed. Modeling for Neo, included: fittings, valves, frames and tubing, between others. These models help in the review process, to make sure regulations are being followed. Another fluid systems project that required modeling is Plant Habitat's TCUI test project. Plant Habitat is a plan to develop a large growth chamber to learn the effects of long-duration microgravity exposure to plants in space. Work for this project included the design and modeling of a duct vent for flow test. Parametric Modeling for these projects was done using Creo Parametric 2.0.

  13. Comparative performance evaluation of Aspergillus lentulus for dye removal through bioaccumulation and biosorption.

    PubMed

    Kaushik, Prachi; Malik, Anushree

    2013-05-01

    Dyes used in various industries are discharged into the environment and pose major environmental concern. In the present study, fungal isolate Aspergillus lentulus was utilized for the treatment of various dyes, dye mixtures and dye containing effluent in dual modes, bioaccumulation (employing growing biomass) and biosorption (employing pre-cultivated biomass). The effect of dye toxicity on the growth of the fungal isolate was studied through phase contrast and scanning electron microscopy. Dye biosorption was studied using first and second-order kinetic models. Effects of factors influencing adsorption and isotherm studies were also conducted. During bioaccumulation, good removal was obtained for anionic dyes (100 mg/l), viz. Acid Navy Blue, Fast Red A and Orange-HF dye (99.4 %, 98.8 % and 98.7 %, respectively) in 48 h. Cationic dyes (10 mg/l), viz. Rhodamine B and Methylene Blue, had low removal efficiency (80.3 % [48 h] and 92.7 % [144 h], respectively) as compared to anionic dyes. In addition to this, fungal isolate showed toxicity response towards Methylene Blue by producing larger aggregates of fungal pellets. To overcome the limitations of bioaccumulation, dye removal in biosorption mode was studied. In this mode, significant removal was observed for anionic (96.7-94.3 %) and cationic (35.4-90.9 %) dyes in 24 h. The removal of three anionic dyes and Rhodamine B followed first-order kinetic model whereas removal of Methylene Blue followed second-order kinetic model. Overall, fungal isolate could remove more than 90 % dye from different dye mixtures in bioaccumulation mode and more than 70 % dye in biosorption mode. Moreover, significant color removal from handmade paper unit effluent in bioaccumulation mode (86.4 %) as well as in biosorption mode (77.1 %) was obtained within 24 h. This study validates the potential of fungal isolate, A. lentulus, to be used as the primary organism for treating dye containing wastewater.

  14. Thermodynamic models in cosmochemical systems.

    NASA Technical Reports Server (NTRS)

    Griffiths, P. R.; Brown, C. W.; Lippincott, E. R.; Dayhoff , M. O.

    1972-01-01

    Generalized computer methods are developed for inferring details of the formation of cosmochemical systems. Compositions of ideal gas mixtures existing in equilibrium with multicomponent solid and liquid phases are calculated. A comparison of computed results with experimental data is made for the ternary system MgO-FeO-SiO2. While the ideal-solution approximation is shown to be inaccurate in dealing with the silicate melts, the stable phases and compositions can be accurately calculated in a system where there are only solids and gas. A model system containing the elements H, O, Si, Mg, S, C, Cl, and F is investigated over a range of compositions involving the gas and ten solid phases, to show the power of the technique in dealing with complex gas-solid equilibria. Systems close to cosmic composition are next considered, both with and without iron.

  15. A study of the mechanism of bleaching cotton using peracids and hydrogen peroxide as model systems

    SciTech Connect

    Winkler, J.

    1997-11-01

    The commercial interest for energy-saving and environmentally friendly bleaching systems has focused on hydrogen peroxide and peracids. Most available literature has been published in patents and little is known about the interfacial mechanism of bleaching. The mechanism of bleaching cotton dyed with the reactive dye 5-(4,6-dichlorotriazinyl)aminofluorescein has been investigated using hydrogen peroxide as a model system. A general strategy for the study of the mechanism and kinetics of bleaching is presented followed by the relevant theory to enable a discriminatory assessment of the experimental data obtained. A brief extension to the industrially relevant class of peracid bleaches is given.

  16. Efficient dye regeneration at low driving force achieved in triphenylamine dye LEG4 and TEMPO redox mediator based dye-sensitized solar cells.

    PubMed

    Yang, Wenxing; Vlachopoulos, Nick; Hao, Yan; Hagfeldt, Anders; Boschloo, Gerrit

    2015-06-28

    Minimizing the driving force required for the regeneration of oxidized dyes using redox mediators in an electrolyte is essential to further improve the open-circuit voltage and efficiency of dye-sensitized solar cells (DSSCs). Appropriate combinations of redox mediators and dye molecules should be explored to achieve this goal. Herein, we present a triphenylamine dye, LEG4, in combination with a TEMPO-based electrolyte in acetonitrile (E(0) = 0.89 V vs. NHE), reaching an efficiency of up to 5.4% under one sun illumination and 40% performance improvement compared to the previously and widely used indoline dye D149. The origin of this improvement was found to be the increased dye regeneration efficiency of LEG4 using the TEMPO redox mediator, which regenerated more than 80% of the oxidized dye with a driving force of only ∼0.2 eV. Detailed mechanistic studies further revealed that in addition to electron recombination to oxidized dyes, recombination of electrons from the conducting substrate and the mesoporous TiO2 film to the TEMPO(+) redox species in the electrolyte accounts for the reduced short circuit current, compared to the state-of-the-art cobalt tris(bipyridine) electrolyte system. The diffusion length of the TEMPO-electrolyte based DSSCs was determined to be ∼0.5 μm, which is smaller than the ∼2.8 μm found for cobalt-electrolyte based DSSCs. These results show the advantages of using LEG4 as a sensitizer, compared to previously record indoline dyes, in combination with a TEMPO-based electrolyte. The low driving force for efficient dye regeneration presented by these results shows the potential to further improve the power conversion efficiency (PCE) of DSSCs by utilizing redox couples and dyes with a minimal need of driving force for high regeneration yields.

  17. Liquid-phase non-thermal plasma-prepared N-doped TiO(2) for azo dye degradation with the catalyst separation system by ceramic membranes.

    PubMed

    Cheng, Hsu-Hui; Chen, Shiao-Shing; Cheng, Yi-Wen; Tseng, Wei-Lun; Wang, Yi-Hui

    2010-01-01

    This study strived to improve the photocatalytic activity by using liquid-phase non-thermal plasma (LPNTP) technology for preparing N-doping TiO(2) as well as to separate/recover the N-dope TiO(2) particles by using ceramic ultrafiltration membrane process. The yellow color N-doped TiO(2) photocatalysts, obtained through the LPNTP process, were characterized with UV-Vis spectroscopy, X-ray diffraction (XRD), and electron spectroscopy for chemical analysis (ESCA). The UV-Vis spectrum of N-doped TiO(2) showed that the absorption band was shifted to 439 nm and the band gap was reduced to 2.82 eV. The structure analysis of XRD spectra showed that the peak positions and the crystal structure remained unchanged as anatase after plasma-treating at 13.5 W for 40 min. The photocatalytic activity of N-doped TiO(2) was evaluated by azo dyes under visible light, and 63% of them was degraded after 16 hours in a continuous-flow photocatalytic system. For membrane separation/recover system, the recovery efficiency reached 99.5% after the ultrafiltration had been carried out for 90 min, and the result indicated that the photocatalyst was able to be separated/recovered completely.

  18. Morphology transformations in tetrabutyl titanate-acetic acid system and sub-micron/micron hierarchical TiO2 for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Huang, Niu; Xie, Yanan; Sebo, Bobby; Liu, Yumin; Sun, Xiaohua; Peng, Tao; Sun, Weiwei; Bu, Chenghao; Guo, Shishang; Zhao, Xingzhong

    2013-11-01

    The concentration of tetrabutyl titanate (TBT) and H2O influence on the reaction kinetics of TBT and acetic acid (AcOH) solvothermal system are systematically studied. It is found that TBT and H2O have greatly accelerated the hydrolysis-condensation process of the TBT-AcOH system. By adjusting those concentrations with reaction time, we prepare five kinds of sub-micron/micron precursors, which are hierarchical structures consisting of different primary building blocks. The morphology of these precursors varies from noninterlaced structures composed of flower-like microsphere and ellipsoid sphere to interlaced structures composed of flower-like microsphere interlaced nanofibers, ellipsoid spheres interlaced flower-like microsphere and nanoparticles interlaced flower-like microsphere. These interlaced structures are synthesized for the first time and are not ordinary mixtures of the noninterlaced structures. After heat treatment, these precursors are transformed to anatase TiO2. Shape-dependent photovoltaic performances of dye-sensitized solar cells (DSSCs) are also discussed. DSSCs based on these hierarchical sub-micron/micron TiO2 show 7.3%-7.9% energy conversion efficiencies, and the devices based on interlaced structures have higher efficiencies (7.4%-7.9%) than those of the devices based on noninterlaced structures (7.3%-7.6%).

  19. Superior Adsorption and Regenerable Dye Adsorbent Based on Flower-Like Molybdenum Disulfide Nanostructure

    NASA Astrophysics Data System (ADS)

    Han, Sancan; Liu, Kerui; Hu, Linfeng; Teng, Feng; Yu, Pingping; Zhu, Yufang

    2017-03-01

    Herein we report superior dye-adsorption performance for flower-like nanostructure composed of two dimensional (2D) MoS2 nanosheets by a facile hydrothermal method, more prominent adsorption of cationic dye compared with anodic dye indicates the dye adsorption performance strongly depends on surface charge of MoS2 nanosheets. The adsorption mechanism of dye is analyzed, the kinetic data of dye adsorption fit well with the pseudo-second-order model, meanwhile adsorption capability at different equilibrium concentrations follows Langmuir model, indicating the favorability and feasibility of dye adsorption. The regenerable property for MoS2 with full adsorption of dye molecules by using alkaline solution were demonstrated, showing the feasibility of reuse for the MoS2, which is promising in its practical water treatment application.

  20. Superior Adsorption and Regenerable Dye Adsorbent Based on Flower-Like Molybdenum Disulfide Nanostructure

    PubMed Central

    Han, Sancan; Liu, Kerui; Hu, Linfeng; Teng, Feng; Yu, Pingping; Zhu, Yufang

    2017-01-01

    Herein we report superior dye-adsorption performance for flower-like nanostructure composed of two dimensional (2D) MoS2 nanosheets by a facile hydrothermal method, more prominent adsorption of cationic dye compared with anodic dye indicates the dye adsorption performance strongly depends on surface charge of MoS2 nanosheets. The adsorption mechanism of dye is analyzed, the kinetic data of dye adsorption fit well with the pseudo-second-order model, meanwhile adsorption capability at different equilibrium concentrations follows Langmuir model, indicating the favorability and feasibility of dye adsorption. The regenerable property for MoS2 with full adsorption of dye molecules by using alkaline solution were demonstrated, showing the feasibility of reuse for the MoS2, which is promising in its practical water treatment application. PMID:28272411

  1. Suppression of cucurbit scab on cucumber leaves by photodynamic dyes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The goal of this study was to test the ability of the photodynamic dyes bengal rose, toluidine blue, and methylene blue, to protect systemically cucumber plants from cucurbit scab. At the stage of one true leaf, water or aqueous solutions of the dyes were applied to the leaf as droplets. When the se...

  2. Cotangent Models for Integrable Systems

    NASA Astrophysics Data System (ADS)

    Kiesenhofer, Anna; Miranda, Eva

    2017-03-01

    We associate cotangent models to a neighbourhood of a Liouville torus in symplectic and Poisson manifolds focusing on b-Poisson/ b-symplectic manifolds. The semilocal equivalence with such models uses the corresponding action-angle theorems in these settings: the theorem of Liouville-Mineur-Arnold for symplectic manifolds and an action-angle theorem for regular Liouville tori in Poisson manifolds (Laurent- Gengoux et al., IntMath Res Notices IMRN 8: 1839-1869, 2011). Our models comprise regular Liouville tori of Poisson manifolds but also consider the Liouville tori on the singular locus of a b-Poisson manifold. For this latter class of Poisson structures we define a twisted cotangent model. The equivalence with this twisted cotangent model is given by an action-angle theorem recently proved by the authors and Scott (Math. Pures Appl. (9) 105(1):66-85, 2016). This viewpoint of cotangent models provides a new machinery to construct examples of integrable systems, which are especially valuable in the b-symplectic case where not many sources of examples are known. At the end of the paper we introduce non-degenerate singularities as lifted cotangent models on b-symplectic manifolds and discuss some generalizations of these models to general Poisson manifolds.

  3. Modelling codependence in biological systems.

    PubMed

    Mandel, J J; Palfreyman, N M; Dubitzky, W

    2007-01-01

    A central aim of systems biology is to elucidate the complex dynamic structure of biological systems within which functioning and control occur. The success of this endeavour requires a dialogue between the two quite distinct disciplines of life science and systems theory, and so drives the need for graphical notations which facilitate this dialogue. Several methods have been developed for modelling and simulating biochemical networks, some of which provide notations for graphicall4y constructing a model. Such notations must support the full panoply of mechanisms of systems biology, including metabolic, regulatory, signalling and transport processes. Notations in systems biology tend to fall into two groups. The first group derives its orientation from conventional biochemical pathway diagrams, and so tends to ignore the role of information processing. The second group focuses on the processing of information, incorporating information-processing ideas from other systems-oriented disciplines, such as engineering and business. This, however, can lead to the two crucial and related difficulties of impedance mismatch and conceptual baggage. Impedance mismatch concerns the rift between non-biological notations and biological reality, which forces the researcher to employ awkward workarounds when modelling uniquely biological mechanisms. Conceptual baggage can arise when, for instance, an engineering notation is adapted to cater for these distinctively biological needs, since these adaptations will, typically, never completely free the notation of the conceptual structure of its original engineering motivation. A novel formalism, codependence modelling, which seeks to combine the needs of the biologist with the mathematical rigour required to support computer simulation of dynamics is proposed here. The notion of codependence encompasses the transformation of both chemical substance and information, thus integrating both metabolic and gene regulatory processes within a

  4. Enhanced removal of hazardous dye form aqueous solutions and real textile wastewater using bifunctional chitin/lignin biosorbent.

    PubMed

    Wawrzkiewicz, Monika; Bartczak, Przemysław; Jesionowski, Teofil

    2017-06-01

    A new biomaterial based on chitin and lignin was prepared and applied for the removal of hazardous dye C.I. Direct Blue 71 (DB71) from aqueous solutions and wastewaters. The dye sorption on the chitin/lignin biosorbent (Ch/L) was examined depending on the initial dye concentration (50-200mg/L), phase contact time (1-1440min), kind of auxiliaries (NaCl, Na2SO4, anionic surfactant SDS) and their concentrations (1-20g/L salts, 0.1-0.75g/L SDS), initial solution pH as well as temperature (20-50°C). The equilibrium and kinetic characteristics of C.I. Direct Blue 71 uptake by chitin/lignin followed by the Freundlich isotherm model and the pseudo-second order model rather than the Langmuir, Tempkin models, and pseudo-first order model. C.I. Direct Blue 71 adsorption on chitin/lignin was spontaneous (-2.86 to -8.14kJ/mol) and endothermic (60.1kJ/mol). The possibilities of dye elution and reuse by means of the batch method were investigated and as follows the chemical reaction is an inseparable sorption mechanism. Purification of wastewaters containing direct dyes was made with 91% efficiency after 1h of phase contact time. For comparison, data obtained or obtained results in the DB71-chitin (Ch) system were also presented.

  5. INTEGRATED HYDROGEN STORAGE SYSTEM MODEL

    SciTech Connect

    Hardy, B

    2007-11-16

    Hydrogen storage is recognized as a key technical hurdle that must be overcome for the realization of hydrogen powered vehicles. Metal hydrides and their doped variants have shown great promise as a storage material and significant advances have been made with this technology. In any practical storage system the rate of H2 uptake will be governed by all processes that affect the rate of mass transport through the bed and into the particles. These coupled processes include heat and mass transfer as well as chemical kinetics and equilibrium. However, with few exceptions, studies of metal hydrides have focused primarily on fundamental properties associated with hydrogen storage capacity and kinetics. A full understanding of the complex interplay of physical processes that occur during the charging and discharging of a practical storage system requires models that integrate the salient phenomena. For example, in the case of sodium alanate, the size of NaAlH4 crystals is on the order of 300nm and the size of polycrystalline particles may be approximately 10 times larger ({approx}3,000nm). For the bed volume to be as small as possible, it is necessary to densely pack the hydride particles. Even so, in packed beds composed of NaAlH{sub 4} particles alone, it has been observed that the void fraction is still approximately 50-60%. Because of the large void fraction and particle to particle thermal contact resistance, the thermal conductivity of the hydride is very low, on the order of 0.2 W/m-{sup o}C, Gross, Majzoub, Thomas and Sandrock [2002]. The chemical reaction for hydrogen loading is exothermic. Based on the data in Gross [2003], on the order of 10{sup 8}J of heat of is released for the uptake of 5 kg of H{sub 2}2 and complete conversion of NaH to NaAlH{sub 4}. Since the hydride reaction transitions from hydrogen loading to discharge at elevated temperatures, it is essential to control the temperature of the bed. However, the low thermal conductivity of the hydride

  6. System modelling for LISA Pathfinder

    NASA Astrophysics Data System (ADS)

    Diaz-Aguiló, Marc; Grynagier, Adrien; Rais, Boutheina

    LISA Pathfinder is the technology demonstrator for LISA, a space-borne gravitational waves observatory. The goal of the mission is to characterise the dynamics of the LISA Technology Package (LTP) to prove that on-board experimental conditions are compatible with the de-tection of gravitational waves. The LTP is a drag-free dynamics experiment which includes a control loop with sensors (interferometric and capacitive), actuators (capacitive actuators and thrusters), controlled disturbances (magnetic coils, heaters) and which is subject to various endogenous or exogenous noise sources such as infrared pressure or solar wind. The LTP experiment features new hardware which was never flown in space. The mission has a tight operation timeline as it is constrained to about 100 days. It is therefore vital to have efficient and precise means of investigation and diagnostics to be used during the on-orbit operations. These will be conducted using the LTP Data Analysis toolbox (LTPDA) which allows for simulation, parameter identification and various analyses (covariance analysis, state estimation) given an experimental model. The LTPDA toolbox therefore contains a series of models which are state-space representations of each component in the LTP. The State-Space Models (SSM) are objects of a state-space class within the LTPDA toolbox especially designed to address all the requirements of this tool. The user has access to a set of linear models which represent every satellite subsystem; the models are available in different forms representing 1D, 2D and 3D systems, each with settable symbolic and numeric parameters. To limit the possible errors, the models can be automatically linked to produce composite systems and closed-loops of the LTP. Finally, for the sake of completeness, accuracy and maintainability of the tool, the models contain all the physical information they mimic (i.e. variable units, description of parameters, description of inputs/outputs, etc). Models

  7. Response surface optimization for efficient dye removal by isolated strain Pseudomonas sp.

    NASA Astrophysics Data System (ADS)

    Senthilkumar, Shanmugam; Perumalsamy, Muthiah; Prabhuy, Harinarayan Janardhana; AhmedBasha, Chiya; Anantharaman, Narayan

    2012-09-01

    Response surface methodology (RSM) involving the central composite design (CCD) was employed to optimize three important process variables for the decolourization of synthetic dye solutions containing Remazol Turquoise Blue (RTB) and Reactive Black 5 (RB5) with isolated bacterial strain Pseudomonas sp. The interaction between three variables i.e. Initial concentration of dye, carbon source and nitrogen source were studied and modeled. According to the Analysis of variance (ANOVA) results the predicted results were found to be in good agreement with experimental results ( R 2: 0.9726; Adj R 2: 0.9480 for RTB and R 2: 0.9789; Adj R 2: 0.9750 for RB5) which indicated excellent evaluation of experimental data from the second order polynomial regression model. Mathematical models were developed by the proposed system, for each process variable showed the effect of each factor and their interactions on biodecolourization process. The optimum concentrations of Dye, Carbon source, and Nitrogen source were found to be 20 mgL-1, 1.5 g/L and 1.5 g/L, respectively for RTB and RB5 to obtain maximum dye removing capacity. Predicted values were validated with experimental results, which indicated appropriateness of the employed model and the success of RSM.

  8. Response surface optimization for efficient dye removal by isolated strain Pseudomonas sp.

    NASA Astrophysics Data System (ADS)

    Senthilkumar, Shanmugam; Perumalsamy, Muthiah; Prabhuy, Harinarayan; AhmedBasha, Chiya; Anantharaman, Narayan

    2012-09-01

    Response surface methodology (RSM) involving the central composite design (CCD) was employed to optimize three important process variables for the decolourization of synthetic dye solutions containing Remazol Turquoise Blue (RTB) and Reactive Black 5 (RB5) with isolated bacterial strain Pseudomonas sp. The interaction between three variables i.e. Initial concentration of dye, carbon source and nitrogen source were studied and modeled. According to the Analysis of variance (ANOVA) results the predicted results were found to be in good agreement with experimental results (R 2: 0.9726; Adj R 2: 0.9480 for RTB and R 2: 0.9789; Adj R 2: 0.9750 for RB5) which indicated excellent evaluation of experimental data from the second order polynomial regression model. Mathematical models were developed by the proposed system, for each process variable showed the effect of each factor and their interactions on biodecolourization process. The optimum concentrations of Dye, Carbon source, and Nitrogen source were found to be 20 mgL-1, 1.5 g/L and 1.5 g/L, respectively for RTB and RB5 to obtain maximum dye removing capacity. Predicted values were validated with experimental results, which indicated appropriateness of the employed model and the success of RSM.

  9. Graph modeling systems and methods

    DOEpatents

    Neergaard, Mike

    2015-10-13

    An apparatus and a method for vulnerability and reliability modeling are provided. The method generally includes constructing a graph model of a physical network using a computer, the graph model including a plurality of terminating vertices to represent nodes in the physical network, a plurality of edges to represent transmission paths in the physical network, and a non-terminating vertex to represent a non-nodal vulnerability along a transmission path in the physical network. The method additionally includes evaluating the vulnerability and reliability of the physical network using the constructed graph model, wherein the vulnerability and reliability evaluation includes a determination of whether each terminating and non-terminating vertex represents a critical point of failure. The method can be utilized to evaluate wide variety of networks, including power grid infrastructures, communication network topologies, and fluid distribution systems.

  10. Excited singlet-state absorption in laser dyes at the XeCl wavelength

    NASA Astrophysics Data System (ADS)

    Taylor, R. S.; Mihailov, S.

    1985-10-01

    The transmission properties of the laser dyes BBQ, PBD, BPBD, α-NPO, p-Quarterphenyl and PPO have been measured using a XeCl (308 nm) excimer laser. A model for the dye saturation which incorporates excited-state absorption was used to estimate the lifetime and the absorption cross section of the first excited singlet-state for each dye.

  11. The emergent neural modeling system.

    PubMed

    Aisa, Brad; Mingus, Brian; O'Reilly, Randy

    2008-10-01

    Emergent (http://grey.colorado.edu/emergent) is a powerful tool for the simulation of biologically plausible, complex neural systems that was released in August 2007. Inheriting decades of research and experience in network algorithms and modeling principles from its predecessors, PDP++ and PDP, Emergent has been redesigned as an efficient workspace for academic research and an engaging, easy-to-navigate environment for students. The system provides a modern and intuitive interface for programming and visualization centered around hierarchical, tree-based navigation and drag-and-drop reorganization. Emergent contains familiar, high-level simulation constructs such as Layers and Projections, a wide variety of algorithms, general-purpose data handling and analysis facilities and an integrated virtual environment for developing closed-loop cognitive agents. For students, the traditional role of a textbook has been enhanced by wikis embedded in every project that serve to explain, document, and help newcomers engage the interface and step through models using familiar hyperlinks. For advanced users, the software is easily extensible in all respects via runtime plugins, has a powerful shell with an integrated debugger, and a scripting language that is fully symmetric with the interface. Emergent strikes a balance between detailed, computationally expensive spiking neuron models and abstract, Bayesian or symbolic systems. This middle level of detail allows for the rapid development and successful execution of complex cognitive models while maintaining biological plausibility.

  12. Probabilistic models for feedback systems.

    SciTech Connect

    Grace, Matthew D.; Boggs, Paul T.

    2011-02-01

    In previous work, we developed a Bayesian-based methodology to analyze the reliability of hierarchical systems. The output of the procedure is a statistical distribution of the reliability, thus allowing many questions to be answered. The principal advantage of the approach is that along with an estimate of the reliability, we also can provide statements of confidence in the results. The model is quite general in that it allows general representations of all of the distributions involved, it incorporates prior knowledge into the models, it allows errors in the 'engineered' nodes of a system to be determined by the data, and leads to the ability to determine optimal testing strategies. In this report, we provide the preliminary steps necessary to extend this approach to systems with feedback. Feedback is an essential component of 'complexity' and provides interesting challenges in modeling the time-dependent action of a feedback loop. We provide a mechanism for doing this and analyze a simple case. We then consider some extensions to more interesting examples with local control affecting the entire system. Finally, a discussion of the status of the research is also included.

  13. Modeling Advance Life Support Systems

    NASA Technical Reports Server (NTRS)

    Pitts, Marvin; Sager, John; Loader, Coleen; Drysdale, Alan

    1996-01-01

    Activities this summer consisted of two projects that involved computer simulation of bioregenerative life support systems for space habitats. Students in the Space Life Science Training Program (SLSTP) used the simulation, space station, to learn about relationships between humans, fish, plants, and microorganisms in a closed environment. One student complete a six week project to modify the simulation by converting the microbes from anaerobic to aerobic, and then balancing the simulation's life support system. A detailed computer simulation of a closed lunar station using bioregenerative life support was attempted, but there was not enough known about system restraints and constants in plant growth, bioreactor design for space habitats and food preparation to develop an integrated model with any confidence. Instead of a completed detailed model with broad assumptions concerning the unknown system parameters, a framework for an integrated model was outlined and work begun on plant and bioreactor simulations. The NASA sponsors and the summer Fell were satisfied with the progress made during the 10 weeks, and we have planned future cooperative work.

  14. On-line diffusion profile of a lipophilic model dye in different depths of a hair follicle in human scalp skin.

    PubMed

    Grams, Ylva Y; Whitehead, Lynne; Lamers, Gerda; Sturmann, Nico; Bouwstra, Joke A

    2005-10-01

    In skin and hair research, drug targeting to the hair follicle is of great interest in the treatment of skin diseases. The aim of this study is to visualize on-line the diffusion processes of a model fluorophore into the hair follicle at different depths using fresh human scalp skin and confocal laser scanning microscopy. Up to a depth of 500 microm in the skin, a fast increase of fluorescence is observed in the gap followed by accumulation of the dye in the hair cuticle. Penetration was also observed via the stratum corneum and the epidermis. Little label reached depths greater than 2000 microm. Fat cells accumulated the label fastest, followed by the cuticular area and the outer root sheath of the hair follicle. Sweat glands revealed very low staining, whereas the bulb at a depth of 4000 microm was visualized only by autofluorescence. From this study, we conclude that on-line visualization is a promising technique to access diffusion processes in deep skin layers even on a cellular level. Furthermore, we conclude that the gap and the cuticle play an important role in the initial diffusion period with the label in the cuticle originating from the gap.

  15. Flashlamp-excited dye laser therapy for treatment of cutaneous vascular lesions

    NASA Astrophysics Data System (ADS)

    Goldberg, David J.

    1990-06-01

    Flashlamp excited dye laser therapy represents an exciting new advance in the treatment of a variety of cutaneous vascular lesions. Portwine stains, angiomas and telangiectases can be treated in all age groups with this laser system. This paper will review the physics of flashlamp dye laser photothermolysis. The differences between argon laser photocoagulation and flashlamp excited dye laser therapy will be reviewed.

  16. Imaging nervous system activity.

    PubMed

    Fields, Douglas R; Shneider, Neil; Mentis, George Z; O'Donovan, Michael J

    2009-10-01

    This unit describes methods for loading ion- and voltage-sensitive dyes into neurons, with a particular focus on the spinal cord as a model system. In addition, we describe the use of these dyes to visualize neural activity. Although the protocols described here concern spinal networks in culture or an intact in vitro preparation, they can be, and have been, widely used in other parts of the nervous system.

  17. Models for multimegawatt space power systems

    SciTech Connect

    Edenburn, M.W.

    1990-06-01

    This report describes models for multimegawatt, space power systems which Sandia's Advanced Power Systems Division has constructed to help evaluate space power systems for SDI's Space Power Office. Five system models and models for associated components are presented for both open (power system waste products are exhausted into space) and closed (no waste products) systems: open, burst mode, hydrogen cooled nuclear reactor -- turboalternator system; open, hydrogen-oxygen combustion turboalternator system; closed, nuclear reactor powered Brayton cycle system; closed, liquid metal Rankine cycle system; and closed, in-core, reactor therminonic system. The models estimate performance and mass for the components in each of these systems. 17 refs., 8 figs., 15 tabs.

  18. Discrete modelling of drapery systems

    NASA Astrophysics Data System (ADS)

    Thoeni, Klaus; Giacomini, Anna

    2016-04-01

    Drapery systems are an efficient and cost-effective measure in preventing and controlling rockfall hazards on rock slopes. The simplest form consists of a row of ground anchors along the top of the slope connected to a horizontal support cable from which a wire mesh is suspended down the face of the slope. Such systems are generally referred to as simple or unsecured draperies (Badger and Duffy 2012). Variations such as secured draperies, where a pattern of ground anchors is incorporated within the field of the mesh, and hybrid systems, where the upper part of an unsecured drapery is elevated to intercept rockfalls originating upslope of the installation, are becoming more and more popular. This work presents a discrete element framework for simulation of unsecured drapery systems and its variations. The numerical model is based on the classical discrete element method (DEM) and implemented into the open-source framework YADE (Šmilauer et al., 2010). The model takes all relevant interactions between block, drapery and slope into account (Thoeni et al., 2014) and was calibrated and validated based on full-scale experiments (Giacomini et al., 2012).The block is modelled as a rigid clump made of spherical particles which allows any shape to be approximated. The drapery is represented by a set of spherical particle with remote interactions. The behaviour of the remote interactions is governed by the constitutive behaviour of the wire and generally corresponds to a piecewise linear stress-strain relation (Thoeni et al., 2013). The same concept is used to model wire ropes. The rock slope is represented by rigid triangular elements where material properties (e.g., normal coefficient of restitution, friction angle) are assigned to each triangle. The capabilities of the developed model to simulate drapery systems and estimate the residual hazard involved with such systems is shown. References Badger, T.C., Duffy, J.D. (2012) Drapery systems. In: Turner, A.K., Schuster R

  19. Hair Dye and Hair Relaxers

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the ...

  20. Water soluble laser dyes

    DOEpatents

    Hammond, Peter R.; Feeman, James F.; Field, George F.

    1998-01-01

    Novel water soluble dyes of the formula I are provided ##STR1## wherein R.sup.1 and R.sup.4 are alkyl of 1 to 4 carbon atoms or hydrogen; or R.sup.1 -R.sup.2 or R.sup.2 -R.sup.4 form part of aliphatic heterocyclic rings; R.sup.2 is hydrogen or joined with R.sup.1 or R.sup.4 as described above; R.sup.3 is --(CH.sub.2).sub.m --SO.sub.3.sup.-, where m is 1 to 6; X is N, CH or ##STR2## where Y is 2 --SO.sub.3.sup.- ; Z is 3, 4, 5 or 6 --SO.sub.3.sup.-. The novel dyes are particularly useful as the active media in water solution dye lasers.

  1. Hair cosmetics: dyes.

    PubMed

    Guerra-Tapia, A; Gonzalez-Guerra, E

    2014-11-01

    Hair plays a significant role in body image, and its appearance can be changed relatively easily without resort to surgical procedures. Cosmetics and techniques have therefore been used to change hair appearance since time immemorial. The cosmetics industry has developed efficient products that can be used on healthy hair or act on concomitant diseases of the hair and scalp. Dyes embellish the hair by bleaching or coloring it briefly, for temporary periods of longer duration, or permanently, depending on the composition of a dye (oxidative or nonoxidative) and its degree of penetration of the hair shaft. The dermatologist's knowledge of dyes, their use, and their possible side effects (contact eczema, cancer, increased porosity, brittleness) can extend to an understanding of cosmetic resources that also treat hair and scalp conditions.

  2. Water soluble laser dyes

    DOEpatents

    Hammond, P.R.; Feeman, J.F.; Field, G.F.

    1998-08-11

    Novel water soluble dyes of the formula 1 are provided by the formula described in the paper wherein R{sup 1} and R{sup 4} are alkyl of 1 to 4 carbon atoms or hydrogen; or R{sup 1}--R{sup 2} or R{sup 2}--R{sup 4} form part of aliphatic heterocyclic rings; R{sup 2} is hydrogen or joined with R{sup 1} or R{sup 4} as described above; R{sup 3} is --(CH{sub 2}){sub m}--SO{sub 3}{sup {minus}}, where m is 1 to 6; X is N, CH or formula 2 given in paper where Y is 2 --SO{sub 3}{sup {minus}} ; Z is 3, 4, 5 or 6 --SO{sub 3}{sup {minus}}. The novel dyes are particularly useful as the active media in water solution dye lasers.

  3. Laser dye technology

    SciTech Connect

    Hammond, P R

    1999-09-01

    The author has worked with laser dyes for a number of years. A first interest was in the Navy blue-green program where a flashlamp pumped dye laser was used as an underwater communication and detection device. It made use of the optical window of sea-water--blue for deep ocean, green for coastal water. A major activity however has been with the Atomic Vapor Laser Isotope Separation Program (AVLIS) at the Lawrence Livermore National Laboratory. The aim here has been enriching isotopes for the nuclear fuel cycle. The tunability of the dye laser is utilized to selectively excite one isotope in uranium vapor, and this isotope is collected electrostatically as shown in Figure 1. The interests in the AVLIS program have been in the near ultra-violet, violet, red and deep-red.

  4. Airfoil flutter model suspension system

    NASA Technical Reports Server (NTRS)

    Reed, Wilmer H. (Inventor)

    1987-01-01

    A wind tunnel suspension system for testing flutter models under various loads and at various angles of attack is described. The invention comprises a mounting bracket assembly affixing the suspension system to the wind tunnel, a drag-link assembly and a compound spring arrangement comprises a plunge spring working in opposition to a compressive spring so as to provide a high stiffness to trim out steady state loads and simultaneously a low stiffness to dynamic loads. By this arrangement an airfoil may be tested for oscillatory response in both plunge and pitch modes while being held under high lifting loads in a wind tunnel.

  5. A new technology for harnessing the dye polluted water and dye collection in a chemical factory.

    PubMed

    Pu, J P; Pu, P M; Hu, C H; Qian, J L; Pu, J X; Hua, J K

    2001-04-01

    A new technology for harnessing the dye polluted water and dye collection was developed. It is based on the enhanced evaporation by using solar, wind and air temperature energy and additional heat-electric energy. It consists of four parts: (1) evaporation carrier system (evaporation carrier and frame for evaporation carrier) for polluted water; (2) polluted water circulating system (pumping-spraying-collecting); (3) heating system; (4) workshop with polluted water reservoir-tanks and rainfall prevention roof. The polluted water was (heated in case necessary) sprayed to the evaporation carrier system and the water was evaporated when it moved in the space and downward along the carrier mainly by using natural (solar, wind and air temperature energy). In case, when there is no roof for the carrier system, the polluted water can be stored in the reservoirs (storage volume for about 20 days). The first 10-25 mm rainfall also need to be stored in the reservoirs to meet the state standard for discharging wastewater. The dye may be collected at the surface in the reservoir-tanks and the crystallized salt may be collected at the bottom plate. The black-color wastewater released by the factory is no more discharged to the surface water system of Taihu Lake Basin. About 2 kg dye and 200 kg industrial salt may be collected from each tone of the polluted water. The non-pollution production of dye may be realized by using this technology with environmental, economical and social benefits.

  6. Ecofriendly biosorption of dyes and metals by bacterial biomass of Aeromonas hydrophila RC1.

    PubMed

    Busi, Siddhardha; Chatterjee, Rahul; Rajkumari, Jobina; Hnamte, Sairengpuii

    2016-03-01

    The ability of dried bacterial biomass in azo dye and heavy metal removal from aqueous solution was explored. Biosorption of three textile dyes, Eriochrome black T (EBT), Acid Red 26 (AR) and Trypan blue (TB) and heavy metals (Pb and Cr) by dried biomass of Aeromonas hydrophila RC1, was investigated in a batch system under various parameters such as dye concentration, contact time, concentration of biomass, pH, and temperature. The experimental results showed that the extent of biosorption for dyes increased with increase in initial concentration of dyes, biomass concentration, contact time, temperature and decreased with increase in pH. The experimental isotherms data were analyzed using Langmuir and Freundlich isotherm equations. The Langmuir model yielded good fit to the experimental data (R² approximately 0.794, 0.844 and 0.969 for the dyes, EBT, AR and TB, respectively) with maximum monolayer adsorption capacity of 58.8 mg g⁻¹ for AR. Similarly results were obtained for heavy metals and the data fit in Langmuir model (R² value of 0.849 and 0.787) with q(m) value of 40 mg g⁻¹ for Pb. The results fit in pseudo first order kinetics with removal upto 96.67 % for Pb. Involvement of the surface characteristics of the biomass in biosorption was studied using scanning electron micrographs, FTIR, EDX and XRD analysis. Thus, use ofA. hydrophila RC1 biomass can be extensively employed in water treatment plants in order to get desired water quality in the most economical way.

  7. Aerobic biodegradation of Azo dye by Bacillus cohnii MTCC 3616; an obligately alkaliphilic bacterium and toxicity evaluation of metabolites by different bioassay systems.

    PubMed

    Prasad, A S Arun; Rao, K V Bhaskara

    2013-08-01

    An obligate alkaliphilic bacterium Bacillus cohnii MTCC 3616 aerobically decolorized a textile azo dye Direct Red-22 (5,000 mg l⁻¹) with 95 % efficiency at 37 °C and pH 9 in 4 h under static conditions. The decolorization of Direct Red-22 (DR-22) was possible through a broad pH (7-11), temperature (10-45 °C), salinity (1-7 %), and dye concentration (5-10 g l⁻¹) range. Decolorization of dye was assessed by UV-vis spectrophotometer with reduction of peak intensity at 549 nm (λ(max)). Biodegradation of dye was analyzed by Fourier transform infrared spectroscopy (FTIR) and high-performance liquid chromatography (HPLC). The FTIR spectrum revealed that B. cohnii specifically targeted azo bond (N=N) at 1,614.42 cm⁻¹ to break down Direct Red-22. Formation of metabolites with different retention times in HPLC analysis further confirmed the degradation of dye. The phytotoxicity test with 5,000 mg l⁻¹ of untreated dye showed 80 % germination inhibition in Vigna mungo, 70 % in Sorghum bicolor and 80 % in Vigna radiata. No germination inhibition was noticed in all three plants by DR-22 metabolites at 5,000 mg l⁻¹. Biotoxicity test with Artemia salina proved the lethality of the azo dye at LC₅₀ of 4 and 8 % for degraded metabolites by causing death of its nauplii compared to its less toxic-degraded metabolites. Bioaccumulation of dye was observed in the mid-gut of A. salina. The cytogenotoxicity assay on the meristematic root tip cells of Allium cepa further confirmed the cytotoxic nature of azo dye (DR-22) with decrease in mitotic index (0.5 % at 500 ppm) and increase in aberrant index (4.56 %) over 4-h exposure period. Genotoxic damages (lagging chromosome, metaphase cluster, chromosome bridges, and dye accumulation in cytoplasm) were noticed at different stages of cell cycle. The degraded metabolites had negligible cytotoxic and genotoxic effects.

  8. Optimization of working cathode position in sleeve-type bioelectrochemical system with inner chamber/outer chamber for azo dye treatment.

    PubMed

    Kong, Fanying; Wang, Aijie; Ren, Hong-Yu

    2015-12-01

    In this study, the optimization of working cathode position in sleeve-type bioelectrochemical system (BES) was evaluated with inner/outer chamber for azo dye decolorization. Results showed that the working position in outer chamber performed better with decolorization efficiencies of 97.8 ± 2.1% (7h) and 94.0 ± 2.3% (16 h) than that in inner chamber as the volume ratio Vcathode:Vanode=1:1 and 3:1, respectively. The current and electrochemical impedance spectroscopy (EIS) analysis indicated that the proton/electron transfer and anolyte diffusion could be improved using outer chamber as working position. The decolorization with increased volume ratio could be further improved through the strategy of increasing substrate concentration, which would provide enough electrons and decrease diffusion resistance, further improving the whole performance with increased outer cathode volume. It has the great potential in sleeve-type configuration application and would create more challenges for process optimization and maintenance.

  9. Fabrication of dye-sensitized solar cell (DSSC) using different particle sizes of TiO2 deposited via nano-particle deposition system (NPDS).

    PubMed

    Kim, Yang-Hee; Kim, Kwang-Su; Lee, Jin-Woong; Kim, Min-Saeng; Choi, Jung-Oh; Ahn, Sung-Hoon; Lee, Caroline Sunyong

    2012-04-01

    TiO2 layers were fabricated using a nano-particle deposition system (NPDS) on transparent conductive oxide (TCO) glass for dye sensitized solar cells (DSSCs). Conventionally, TiO2 paste for working electrodes has been fabricated using paste type methods. The fabricated paste composed of a mixture of nano-sized TiO2 powders, binders and solutions is then painted on TCO glass. After drying, the TiO2 layer on TCO glass is sintered to make a path for electron transfer. TiO2 layers formed by this paste type method require numerous steps, which can be time consuming. In this study, TiO2 powders were sprayed directly on TCO glass using NPDS in order to simplify the fabrication steps. To improve porosity and produce scattering layers, commercial nanocrystalline TiO, powders with different sizes were alternately deposited. Moreover, powders with different sizes were mixed and deposited on the TCO glass. The results indicate that the DSSCs with a TiO2 layer composed of different particle sizes had better cell performance than the cells assembled with single-sized TiO2 particles. Therefore, this study shows that a dry TiO2 coating process is possible for DSSC fabrication to improve its cell efficiencies, and this method can easily be applied on flexible substrates since NPDS is a room-temperature deposition process.

  10. Passive apparatus for stabilizing a flashlamp-pumped dye laser

    SciTech Connect

    De Wilde, M.A.; Decker, L.J.

    1986-04-29

    A flash lamp pumped, dye laser apparatus is described which consists of a flash lamp and a liquid dye solution in a transparent compartment proximate to the flash lamp. The compartment is also connected to a tubular circulatory system for moving the liquid dye. The dye solution is activated by flashing of the lamp for lasing to emit light, the lamp and compartment enclosed in a cooling first water jacket, the jacket enclosing deionized water for cooling, an improved cooling system wherein the temperature of the deionized water and the liquid dye solution are maintained within 0.5/sup 0/C of one another, enabling the laser for pulsing at a stabilized 10 pulses per second rate.

  11. Dye filled security seal

    DOEpatents

    Wilson, Dennis C. W.

    1982-04-27

    A security seal for providing an indication of unauthorized access to a sealed object includes an elongate member to be entwined in the object such that access is denied unless the member is removed. The elongate member has a hollow, pressurizable chamber extending throughout its length that is filled with a permanent dye under greater than atmospheric pressure. Attempts to cut the member and weld it together are revealed when dye flows through a rupture in the chamber wall and stains the outside surface of the member.

  12. Physical and chemical investigations on natural dyes

    NASA Astrophysics Data System (ADS)

    Acquaviva, S.; D'Anna, E.; de Giorgi, M. L.; Della Patria, A.; Baraldi, P.

    2010-09-01

    Natural dyes have been used extensively in the past for many purposes, such us to colour fibers and to produce inks, watercolours and paints, but their use declined rapidly after the discovery of synthetic colours. Nowadays we witness a renewed interest, as natural dyes are neither toxic nor polluting. In this work, physical and chemical properties of four selected dyes, namely red (Madder), yellow (Weld and Turmeric) and blue (Woad) colours, produced by means of traditional techniques at the Museo dei Colori Naturali (Lamoli, Italy), have been investigated. The chromatic properties have been studied through the reflectance spectroscopy, a non-invasive technique for the characterisation of chromaticity. Reflection spectra both from powders and egg-yolk tempera models have been acquired to provide the typical features of the dyes in the UV-vis spectral range. Moreover, to assess the feasibility of laser cleaning procedures, tempera layers were investigated after irradiation with an excimer laser. Micro Raman spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-Ray analyses have complemented the survey, returning compositional and morphological information as well. Efforts have been made to give scientific feedback to the production processes and to support the research activity in the restoration of the artworks where these dyes were employed.

  13. Modeling and experiment of dye-sensitized solar cell with vertically aligned ZnO nanorods through chemical bath deposition

    NASA Astrophysics Data System (ADS)

    Wahyuono, Ruri Agung; Risanti, Doty D.

    2015-01-01

    A theoretical model based on electron diffusion differential equation and Schottky barrier model was developed to determine the current-voltage characteristics of DSSC. To verify the model DSSC with ZnO nanorods photoelectrode which was chemically bath deposited onto the TCO was fabricated. According to modeling results, increasing of recombination current density J at these interfaces results in a decrease in Schottky barrier height φb and therefore improves the photovoltage under the open-circuit condition. It is found that the open-circuit voltage remains constant when the TCO/ZnO Schottky barrier height was varied in the range of 0.45 - 0.6 eV. This theoretical model consistents with the experimental result in which the fabricated DSSCs can produce conversion efficiency in the range of 0.98 - 1.16%. The trend in photovoltage calculated in the theoretical model basically agrees with the experimental result, although the calculated photocurrent is somewhat over estimated compared to the experimental results. The model presents that the ideality factor for ZnO nanorods, which also contributes to the enhancement of photovoltage, increases in the range of 2.75 - 3.0 as the annealing temperature is increased in the experiment.

  14. Quantitative Predictive Models for Systemic Toxicity (SOT)

    EPA Science Inventory

    Models to identify systemic and specific target organ toxicity were developed to help transition the field of toxicology towards computational models. By leveraging multiple data sources to incorporate read-across and machine learning approaches, a quantitative model of systemic ...

  15. Modeling software systems by domains

    NASA Technical Reports Server (NTRS)

    Dippolito, Richard; Lee, Kenneth

    1992-01-01

    The Software Architectures Engineering (SAE) Project at the Software Engineering Institute (SEI) has developed engineering modeling techniques that both reduce the complexity of software for domain-specific computer systems and result in systems that are easier to build and maintain. These techniques allow maximum freedom for system developers to apply their domain expertise to software. We have applied these techniques to several types of applications, including training simulators operating in real time, engineering simulators operating in non-real time, and real-time embedded computer systems. Our modeling techniques result in software that mirrors both the complexity of the application and the domain knowledge requirements. We submit that the proper measure of software complexity reflects neither the number of software component units nor the code count, but the locus of and amount of domain knowledge. As a result of using these techniques, domain knowledge is isolated by fields of engineering expertise and removed from the concern of the software engineer. In this paper, we will describe kinds of domain expertise, describe engineering by domains, and provide relevant examples of software developed for simulator applications using the techniques.

  16. Automated parking garage system model

    NASA Technical Reports Server (NTRS)

    Collins, E. R., Jr.

    1975-01-01

    A one-twenty-fifth scale model of the key components of an automated parking garage system is described. The design of the model required transferring a vehicle from an entry level, vertically (+Z, -Z), to a storage location at any one of four storage positions (+X, -X, +Y, +Y, -Y) on the storage levels. There are three primary subsystems: (1) a screw jack to provide the vertical motion of the elevator, (2) a cam-driven track-switching device to provide X to Y motion, and (3) a transfer cart to provide horizontal travel and a small amount to vertical motion for transfer to the storage location. Motive power is provided by dc permanent magnet gear motors, one each for the elevator and track switching device and two for the transfer cart drive system (one driving the cart horizontally and the other providing the vertical transfer). The control system, through the use of a microprocessor, provides complete automation through a feedback system which utilizes sensing devices.

  17. Partially purified bitter gourd (Momordica charantia) peroxidase catalyzed decolorization of textile and other industrially important dyes.

    PubMed

    Akhtar, Suhail; Ali Khan, Amjad; Husain, Qayyum

    2005-11-01

    The aim of this study was to evaluate the enzymatic action of partially purified bitter gourd peroxidase for the degradation/decolorization of complex aromatic structures. Twenty-one dyes, with a wide spectrum of chemical groups, currently being used by the textile and other important industries have been selected for the study. Here, for the first time we have shown peroxidases from Momordica charantia (300 EU/gm of vegetable) to be highly effective in decolorizing industrially important dyes. Dye solutions, containing 50-200 mg dye/l, were used for the treatment with bitter gourd peroxidase (specific activity of 99.0 EU/mg protein). M. charantia peroxidases were able to decolorize most of the textile dyes by forming insoluble precipitate. When the textile dyes were treated with increasing concentration of enzyme, it was observed that greater fraction of the color was removed but four out of eight reactive dyes were recalcitrant to decolorization by bitter gourd peroxidase. Step-wise addition of enzyme to the decolorizing reaction mixture at the interval of 1h further enhanced the dye decolorization. The rate of decolorization was enhanced when the dyes were incubated with fixed quantity of enzyme for increasing times. Decolorization of non-textile dyes resulted in the degradation and removal of dyes from the solution without any precipitate formation. Decolorization rate was drastically increased when the textile and other industrially important non-textile dyes were treated with bitter gourd peroxidase in presence of 1.0 mM 1-hydroxybenzotriazole. Complex mixtures of dyes were prepared by taking three to four reactive textile and non-textile dyes in equal proportions. Each mixture was decolorized by more than 80% when treated with the enzyme in presence of 1.0 mM 1-hydroxybenzotriazole. Our data suggest that the peroxidase/mediator system is an effective biocatalyst for the treatment of effluents containing recalcitrant dyes from textile, dye manufacturing

  18. Effect of dyeing on antibacterial efficiency of silver coated cotton fabrics

    NASA Astrophysics Data System (ADS)

    Shahidi, Sheila; Rezaee, Sahar; Hezavehi, Emadaldin

    2014-04-01

    Despite numerous investigations during recent decades in the field of antimicrobial treating textile fibers using silver, many obscurities remain regarding the durability and dyeing ability and the influences of dyeing on the antimicrobial effectiveness of silver-treated fibers. In this research work, the cotton fabrics were sputtered using DC magnetron sputtering system for different times of exposure by silver. Then the silver coated samples were dyed by different classes of synthetic and natural dyes. The dye ability of coated samples was compared with untreated cotton. The reflective spectrophotometer was used for this purpose. The morphology of the cotton fabrics before and after dyeing was observed using a scanning electron microscope (SEM). The antibacterial activity of samples before and after dyeing, were investigated and compared. For antibacterial investigation, the antibacterial counting tests were used. It was concluded that, dyeing does not have any negative effect on antibacterial activity of coated samples and very good antibacterial activity was achieved after dyeing.

  19. Salicylic Acid-Based Organic Dyes Acting as the Photosensitizer for Solar Cells.

    PubMed

    Hong, Sungjun; Park, Jae-Hyeong; Han, Ah-Reum; Ko, Kwan-Woo; Eom, Jin Hee; Namgoong, Sung Keon; Lo, Alvie S V; Gordon, Keith C; Yoon, Sungho; Han, Chi-Hwan

    2016-05-01

    A D-π-A metal-free organic dye, featuring salicylic acid as a novel acceptor/anchoring unit, has been designed, synthesized and applied to dye-sensitized solar cell. The detailed photophysical, electrochemical, photovoltaic and sensitizing properties of the organic dye were investigated, in addition to the computational studies of the dye and dye-(TiO2)6 system. A solar cell device using this new organic dye as a sensitizer produced a solar to electric power conversion efficiency (PCE) of 3.49% (J(sc) = 6.69 mAcm-2, V(oc) = 0.74 V and ff = 0.70) under 100 mWcm(-2) simulated AM 1.5 G solar irradiation, demonstrating that the salicylic acid-based organic dye is a suitable alternative to currently used organometallic dyes.

  20. Models of Multiple System Atrophy

    PubMed Central

    Fellner, Lisa; Wenning, Gregor K.; Stefanova, Nadia

    2016-01-01

    Multiple system atrophy (MSA) is a predominantly sporadic, adult-onset, fatal neurodegenerative disease of unknown etiology. MSA is characterized by autonomic failure, levodopa-unresponsive parkinsonism, cerebellar ataxia and pyramidal signs in any combination. MSA belongs to a group of neurodegenerative disorders termed α-synucleinopathies, which also include Parkinson’s disease and dementia with Lewy bodies. Their common pathological feature is the occurrence of abnormal α-synuclein positive inclusions in neurons or glial cells. In MSA, the main cell type presenting aggregates composed of α-synuclein are oligodendroglial cells. This pathological hallmark, also called glial cytoplasmic inclusions (GCIs), is associated with progressive and profound neuronal loss in various regions of the brain. The development of animal models of MSA is justified by the limited understanding of the mechanisms of neurodegeneration and GCIs formation, which is paralleled by a lack of therapeutic strategies. Two main types of rodent models have been generated to replicate different features of MSA neuropathology. On one hand, neurotoxin-based models have been produced to reproduce neuronal loss in substantia nigra pars compacta and striatum. On the other hand, transgenic mouse models with overexpression of α-synuclein in oligodendroglia have been used to reproduce GCIs-related pathology. This chapter gives an overview of the atypical Parkinson’s syndrome MSA and summarizes the currently available MSA animal models and their relevance for pre-clinical testing of disease-modifying therapies. PMID:24338664

  1. A comparative examination of the adsorption mechanism of an anionic textile dye (RBY 3GL) onto the powdered activated carbon (PAC) using various the isotherm models and kinetics equations with linear and non-linear methods

    NASA Astrophysics Data System (ADS)

    Açıkyıldız, Metin; Gürses, Ahmet; Güneş, Kübra; Yalvaç, Duygu

    2015-11-01

    The present study was designed to compare the linear and non-linear methods used to check the compliance of the experimental data corresponding to the isotherm models (Langmuir, Freundlich, and Redlich-Peterson) and kinetics equations (pseudo-first order and pseudo-second order). In this context, adsorption experiments were carried out to remove an anionic dye, Remazol Brillant Yellow 3GL (RBY), from its aqueous solutions using a commercial activated carbon as a sorbent. The effects of contact time, initial RBY concentration, and temperature onto adsorbed amount were investigated. The amount of dye adsorbed increased with increased adsorption time and the adsorption equilibrium was attained after 240 min. The amount of dye adsorbed enhanced with increased temperature, suggesting that the adsorption process is endothermic. The experimental data was analyzed using the Langmuir, Freundlich, and Redlich-Peterson isotherm equations in order to predict adsorption isotherm. It was determined that the isotherm data were fitted to the Langmuir and Redlich-Peterson isotherms. The adsorption process was also found to follow a pseudo second-order kinetic model. According to the kinetic and isotherm data, it was found that the determination coefficients obtained from linear method were higher than those obtained from non-linear method.

  2. Estimation of Fluorescent Dye Amount in Tracer Dye Test

    NASA Astrophysics Data System (ADS)

    Pekkan, Emrah; Balkan, Erman; Balkan, Emir

    2015-04-01

    Karstic groundwater is more influenced by human than the groundwater that disperse in pores. On the other hand karstic groundwater resources, in addition to providing agricultural needs, livestock breeding, drinking and domestic water in most of the months of the year, they also supply drinking water to the wild life at high altitudes. Therefore sustainability and hydrogeological investigation of karstic resources is critical. Tracing techniques are widely used in hydrologic and hydrogeologic studies to determine water storage, flow rate, direction and protection area of groundwater resources. Karanfil Mountain (2800 m), located in Adana, Turkey, is one of the karstic recharge areas of the natural springs spread around its periphery. During explorations of the caves of Karanfil mountain, a 600 m deep cave was found by the Turkish and Polish cavers. At the bottom of the cave there is an underground river with a flow rate of approximately 0.5 m3/s during August 2014. The main spring is located 8 km far from the cave's entrance and its mean flow rate changes between 3.4 m3/s and 0.21 m3/s in March and September respectively according to a flowrate observation station of Directorate of Water Works of Turkey. As such frequent storms, snowmelt and normal seasonal variations in rainfall have a significant and rapid effect on the volume of this main spring resource. The objective of our research is to determine and estimate dye amount before its application on the field inspired from the previously literature on the subject. This estimation is intended to provide a preliminary application of a tracer test of a karstic system. In this study dye injection, inlet point will be an underground river located inside the cave and the observation station will be the spring that is approximately 8 km far from the cave entrance. On the other hand there is 600 meter elevation difference between cave entrance and outlet spring. In this test Rodamin-WT will be used as tracer and the

  3. Alzheimer's Dye Test?

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Massachusetts Institute of Technology (MIT) scientists have developed a new dye that could offer noninvasive early diagnosis of Alzheimer's disease, a discovery that could aid in monitoring the progression of the disease and in studying the efficacy of new treatments to stop it. The work is published in Angewandte Chemie. Today, doctors can only…

  4. Oxidative degradation of azo dyes using tourmaline.

    PubMed

    Wang, Cuiping; Zhang, Yanwei; Yu, Li; Zhang, Zhiyuan; Sun, Hongwen

    2013-09-15

    This study aimed to investigate the catalyzed degradation ability of tourmaline on the dyes methylene blue (MB), rhodamine B (RhB), and congo red (CR) at different pH values. Interestingly, tourmaline strongly adsorbed anionic dyes, but it did not adsorb cationic dyes. When H₂O₂ was introduced into the tourmaline-dye systems, the degradation percentage for CR catalysis by tourmaline was lower than the percentage of adsorption, whereas the opposite was true for MB and RhB systems. Notably, the catalyzed degradation decreased from 100% to 45% for MB, 100% to 15% for RhB and 100% to 25% for CR as the pH increased from 3.0 to 10.0, respectively, which was much greater than the degradation obtained for previously reported materials at pH values ranging from 4.0 to 10.0. Tourmaline catalytically degraded the dyes over a broad range of pH values, which was attributed to tourmaline automatically adjusting the pH of the dye solutions to approximately 5.5 from an initial range of 4.2-10.0. An electron paramagnetic resonance spin trapping technique observed peroxyl (ROO·) and alkoxy (RO·) or alkyl (R·) radicals originated from the attack of ·OH radicals and O₂(·-) radicals, indicating that these radicals were involved in the catalyzed degradation of MB. Importantly, four intermediate products of MB at m/z 383, 316, 203 and 181 were observed by LC/MS.

  5. Dye-sensitized composite semiconductor nanostructures

    NASA Astrophysics Data System (ADS)

    Tennakone, K.; Bandaranayake, P. K. M.; Jayaweera, P. V. V.; Konno, A.; Kumara, G. R. R. A.

    2002-04-01

    Understanding of the charge transport and recombination mechanisms of dye-sensitized solar cells based on semiconductor nanostructures is essential for the improvement of their performance. A great deal of information on these systems have been obtained from studies on a single material (mostly TiO 2 and to a lesser extent ZnO and SnO 2). We have conducted extensive measurements on composite dye-sensitized nanosturctures and found that the composite systems possess unusual properties. Dye-sensitized photoelectrochemical cells made from nanocrystalline films of some materials (e.g., SnO 2) yield comparatively small open-circuit voltages and energy and quantum conversion efficiencies, despite excellent dye-semiconductor interaction. However, on deposition of ultra-thin shells of insulators or high band gap semiconductors on the crystallites, a dramatic increase in the above parameters is observed. Outer shells were found to have insignificant or in most cases a negative effect on TiO 2 films. We explain the above findings on the basis of vast differences in the leakage rates of trapped electrons in different materials which is sensitive to the effective electron mass. Electrons injected to the conduction band in dye-sensitization enter into shallow traps from which they get thermally reemitted to the conduction band. The building up of the electron quasi-fermi level and transport depends on this process. The spread of the hydrogenic wave function of a trapped electron increases inverse exponentially with the effective mass so that the electron leakage and their recombination with acceptors ‘outside’ become severe when the crystallite size is comparable to the Bohr radius of the trapped electron. Such recombinations are effectively suppressed by deposition of thin films on the crystallites. Excited dye molecules anchored to the outer shell injects electrons to the conduction band via tunneling.

  6. ISSM: Ice Sheet System Model

    NASA Technical Reports Server (NTRS)

    Larour, Eric; Schiermeier, John E.; Seroussi, Helene; Morlinghem, Mathieu

    2013-01-01

    In order to have the capability to use satellite data from its own missions to inform future sea-level rise projections, JPL needed a full-fledged ice-sheet/iceshelf flow model, capable of modeling the mass balance of Antarctica and Greenland into the near future. ISSM was developed with such a goal in mind, as a massively parallelized, multi-purpose finite-element framework dedicated to ice-sheet modeling. ISSM features unstructured meshes (Tria in 2D, and Penta in 3D) along with corresponding finite elements for both types of meshes. Each finite element can carry out diagnostic, prognostic, transient, thermal 3D, surface, and bed slope simulations. Anisotropic meshing enables adaptation of meshes to a certain metric, and the 2D Shelfy-Stream, 3D Blatter/Pattyn, and 3D Full-Stokes formulations capture the bulk of the ice-flow physics. These elements can be coupled together, based on the Arlequin method, so that on a large scale model such as Antarctica, each type of finite element is used in the most efficient manner. For each finite element referenced above, ISSM implements an adjoint. This adjoint can be used to carry out model inversions of unknown model parameters, typically ice rheology and basal drag at the ice/bedrock interface, using a metric such as the observed InSAR surface velocity. This data assimilation capability is crucial to allow spinning up of ice flow models using available satellite data. ISSM relies on the PETSc library for its vectors, matrices, and solvers. This allows ISSM to run efficiently on any parallel platform, whether shared or distrib- ISSM: Ice Sheet System Model NASA's Jet Propulsion Laboratory, Pasadena, California uted. It can run on the largest clusters, and is fully scalable. This allows ISSM to tackle models the size of continents. ISSM is embedded into MATLAB and Python, both open scientific platforms. This improves its outreach within the science community. It is entirely written in C/C++, which gives it flexibility in its

  7. Modeling of the antenna of plant photosynthesis in an aqueous micellar system

    SciTech Connect

    Dzhabiev, T.S.; Nadtochenko, V.A.; Rubtsov, I.V.; Smirnov, V.A.

    1987-12-01

    One of the main problems of chemical bionics is the modeling of plant photosynthesis for the creation of an artificial system for the conversion of light energy to the energy of chemical bonds. This work presents results on emissionless transport of the energy of excitation from three dyes that absorb in various regions of the solar radiation spectrum to an analog of the reaction center of natural photosynthesis, where the target reaction of separation of charges with storage of part of the energy of the light quantum in the form of chemical products is then carried out.

  8. Cooperative coadsorption of 4-nitrophenol and basic yellow 28 dye onto an iron organo-inorgano pillared montmorillonite clay.

    PubMed

    Zermane, Faiza; Bouras, Omar; Baudu, Michel; Basly, Jean-Philippe

    2010-10-01

    Sorption properties of an iron surfactant-modified pillared montmorillonite (Fe-SMPM) toward two organic pollutants, basic yellow 28 dye (BY28) and 4-nitrophenol (4-NP), were studied at different pH values in both single component and binary pollutant systems. The pseudo-first-order model fits well with the kinetic data obtained in single component studies and sorption capacities of both BY28 and 4-NP increased with the pH value. A sorption synergetic mechanism was observed in binary systems; 4-nitrophenol adsorption was enhanced by the presence of BY28 in the mixture and increased with dye concentrations. Isotherms were described using the Freundlich model in single component systems and the Sheindorf-Rebhun-Sheintuch (SRS) model, an extended Freundlich model, in binary mixtures systems. Hydrophobic interactions between the surfactant-modified pillared clay and the pollutants were suggested to explain the sorption mechanisms.

  9. Photochemistry of coumarin laser dyes

    SciTech Connect

    von Trebra, R.J.

    1984-01-01

    Coumarin laser dyes are widely used in dye lasers for the generation of tunable laser light in the blue-green spectral region. As in the case with most laser dyes, coumarin dyes undergo photochemical reactions that interfere with simulated emission and result in loss of laser power output. This thesis describes the photochemistry of coumarin laser dyes under both anaerobic and aerobic conditions and some attempts to extend the useful lifetime of several dyes in dye lasers. Irradiation of Coumarin 311, 7-dimethylamino-4-methyl-coumarin (15), in oxygen-free ethanol solution results in the inefficient dye destruction. Products formed absorb light at the lasing wavelength of the dye, interfere with stimulated emission, and decrease the power output of the dye laser. Addition of the sulfur free radical chain transfer agents ethanethiol and ethyl disulfide retard the rate of formation of photoproducts absorbing at the lasing wavelengths. Deuterium incorporation, from the irradiation of Coumarin 311 in the presence of ethanethiol-S-d and ethyl disulfide, indicates that photoproducts most likely result from the reactions of free radicals which are generated in a bimolecular reaction between excited Coumarin 311 and ground state Coumarin 311. Ethanethiol and ethyl disulfide are shown to decrease the rate of power loss from a Coumarin 1 (3) dye laser. The naturally occurring amino acid cysteine acts similarly.

  10. Modeling excitable systems: Reentrant tachycardia

    NASA Astrophysics Data System (ADS)

    Lancaster, Jarrett L.; Hellen, Edward H.; Leise, Esther M.

    2010-01-01

    Excitable membranes are an important type of nonlinear dynamical system, and their study can be used to provide a connection between physical and biological circuits. We discuss two models of excitable membranes important in cardiac and neural tissues. One model is based on the Fitzhugh-Nagumo equations, and the other is based on a three-transistor excitable circuit. We construct a circuit that simulates reentrant tachycardia and its treatment by surgical ablation. This project is appropriate for advanced undergraduates as a laboratory capstone project or as a senior thesis or honors project and can also be a collaborative project, with one student responsible for the computational predictions and another for the circuit construction and measurements.

  11. Screening of freshwater fungi for decolorizing multiple synthetic dyes.

    PubMed

    Yang, Panpan; Shi, Wenxiao; Wang, Hongkai; Liu, Hongmei

    The biodegradation of synthetic dyes by fungi is emerging as an effective and promising approach. In the present study, freshwater fungal strains isolated from submerged woods were screened for the decolorization of 7 synthetic dyes. Subsequently, 13 isolates with high decolorization capability were assessed in a liquid system; they belonged to 9 different fungal species. Several strains exhibited a highly effective decolorization of multiple types of dyes. New absorbance peaks appeared after the treatment with 3 fungal strains, which suggests that a biotransformation process occurred through fungal biodegradation. These results showed the unexploited and valuable capability of freshwater fungi for the treatment of dye-containing effluents. The ability of certain fungi to decolorize dyes is reported here for the first time.

  12. Optical parameters of TN display with dichroic dye

    NASA Astrophysics Data System (ADS)

    Olifierczuk, Marek; Zielinski, Jerzy; Perkowski, Pawel

    2000-05-01

    The present work contain the studies on optical parameters (contrast ratio, viewing angle, birefringence and brightness) of twisted nematic display with black dichroic dye which is designed for an application in large-area information and advertising systems. The numerical optimization of display with a dye has been done. The absorption characteristic of the dye has been obtained. Birefringence of doped mixtures (Delta) n has been measured. The contrast ratio of doped mixtures has been measured in wide temperature range from -25 degree(s)C to +70 degree(s)C. The angle characteristics of contrast ratio for +20 degree(s)C have been obtained. In the work the detailed results describing the effect of a dye on temperature dependence of birefringence and contrast ratio, moreover, the effect of dye on the viewing angle for the first and second transmission minimum will be presented. Additionally, the dielectric characteristics of different mixtures will be shown.

  13. IR-780 Dye for Near-Infrared Fluorescence Imaging in Prostate Cancer

    PubMed Central

    Yi, Xiaomin; Yan, Fei; Wang, Fuli; Qin, Weijun; Wu, Guojun; Yang, Xiaojian; Shao, Chen; Chung, Leland W.K.; Yuan, Jianlin

    2015-01-01

    Background The aim of this study was to investigate near-infrared fluorescence (NIRF) imaging as a novel imaging modality that allows for early detection of cancer and real-time monitoring to acquire related information. IR-780 iodide, a lipophilic dye, accumulates selectively in breast cancer cells and drug-resistant human lung cancer cells, with a peak emission at 780 nm that can be easily detected by the NIRF imaging system. The application of IR-780 for prostate cancer imaging was thoroughly investigated to further expand its clinical value. Material/Methods The impact of IR-780 on the survival of prostate cancer cells PC-3 and LNCaP as well as normal prostate epithelial cells RWPE-1 was determined. Duration of IR-780 dye staining was optimized in PC-3 cells. The involvement of specific OATP1B3 inhibitor in the selective accumulation of IR-780 was investigated. IR-780 for prostate cancer imaging was carried out in athymic nude mouse models and, acute toxicity of IR-780 was evaluated. Results IR-780 incubation resulted in a dose-dependent inhibition to cell proliferation. Mean fluorescence intensity of prostate cancer cells peaked at 20-min IR-780 incubation. Specific uptake of IR-780 dye in prostate cancer cells was mainly through the function of OATP1B3. We also demonstrated that NIRF dye effectively identified the subcutaneous prostate cancer xenografts, subsequently confirmed by histological examination. There was no significant impact on the physical activity, weight, and tissue histology of BABL/C mice with 10-fold imaging dose of 1-month IR-780 dye administration. Conclusions NIRF imaging using IR-780 dye is a feasible and practicable method for prostate cancer detection, with potential tumor-killing ability, although more investigations are needed before clinical translation. PMID:25686161

  14. Modeling Systems of Dependent Components

    DTIC Science & Technology

    2014-09-17

    Ross Sheldon Ross , Babak Haji 611102 c. THIS PAGE The public reporting burden for this collection of information is estimated to average 1 hour per...08/18/2011 Received Paper 3.00 6.00 7.00 5.00 4.00 1.00 2.00 Sheldon Ross . Simulation Analysis of System Life when Component Lives are Determined by...Stochastic Model , Annals of Operations Research (02 2012) Sheldon Ross . A Markov Chai Choice Problem , Probability in the Engineering and

  15. Synthesis of interpenetrating network hydrogel from poly(acrylic acid-co-hydroxyethyl methacrylate) and sodium alginate: modeling and kinetics study for removal of synthetic dyes from water.

    PubMed

    Mandal, Bidyadhar; Ray, Samit Kumar

    2013-10-15

    Several interpenetrating network (IPN) hydrogels were made by free radical in situ crosslink copolymerization of acrylic acid (AA) and hydroxy ethyl methacrylate in aqueous solution of sodium alginate. N,N'-methylenebisacrylamide (MBA) was used as comonomer crosslinker for making these crosslink hydrogels. All of these hydrogels were characterized by carboxylic content, FTIR, SEM, XRD, DTA-TGA and mechanical properties. Swelling, diffusion and network parameters of the hydrogels were studied. These hydrogels were used for adsorption of two important synthetic dyes, i.e. Congo red and methyl violet from water. Isotherms, kinetics and thermodynamics of dye adsorption by these hydrogels were also studied.

  16. Vegetable-based dye-sensitized solar cells.

    PubMed

    Calogero, Giuseppe; Bartolotta, Antonino; Di Marco, Gaetano; Di Carlo, Aldo; Bonaccorso, Francesco

    2015-05-21

    There is currently a large effort to improve the performance of low cost renewable energy devices. Dye-sensitized solar cells (DSSCs) are emerging as one of the most promising low cost photovoltaic technologies, addressing "secure, clean and efficient solar energy conversion". Vegetable dyes, extracted from algae, flowers, fruit and leaves, can be used as sensitizers in DSSCs. Thus far, anthocyanin and betalain extracts together with selected chlorophyll derivatives are the most successful vegetable sensitizers. This review analyses recent progress in the exploitation of vegetable dyes for solar energy conversion and compares them to the properties of synthetic dyes. We provide an in-depth discussion on the main limitation of cell performance e.g. dye degradation, effective electron injection from the dye into the conduction band of semiconducting nanoparticles, such as titanium dioxide and zinc oxide, outlining future developments for the use of vegetable sensitizers in DSSCs. We also discuss the cost of vegetable dyes and how their versatility can boost the advancement of new power management solutions, especially for their integration in living environments, making the practical application of such systems economically viable. Finally, we present our view on future prospects in the development of synthetic analogues of vegetable dyes as sensitizers in DSSCs.

  17. Adsorption of basic dyes from aqueous solution onto pumice powder.

    PubMed

    Akbal, Feryal

    2005-06-15

    The adsorption of methylene blue and crystal violet on pumice powder samples of varying compositions was investigated using a batch adsorption technique. The effects of various experimental parameters, such as adsorbent dosage, initial dye concentration, and contact time, were also investigated. The extent of dye removal increased with decreased initial concentration of the dye and also increased with increased contact time and amount of adsorbent used. Adsorption data were modeled using the Freundlich adsorption isotherm. The adsorption kinetic of methylene blue and crystal violet could be described by the pseudo-second-order reaction model.

  18. Nanoparticulate Dye-Semiconductor Hybrid Materials Formed by Electrochemical Self-Assembly as Electrodes in Photoelectrochemical Cells

    NASA Astrophysics Data System (ADS)

    Nonomura, Kazuteru; Loewenstein, Thomas; Michaelis, Esther; Kunze, Peter; Schiek, Manuela; Reemts, Jens; Yoshie Iwaya, Mirian; Wark, Michael; Rathousky, Jiri; Al-Shamery, Katharina; Kittel, Achim; Parisi, Jürgen; Wöhrle, Dieter; Yoshida, Tsukasa; Schlettwein, Derck

    2009-08-01

    Dye-sensitized zinc oxide thin films were prepared, characterized and optimized for applications as photoelectrochemically active electrodes. Conditions were established under which crystalline thin films of ZnO with a porous texture were formed by electrochemically induced crystallization controlled by structure-directing agents (SDA). Dye molecules were adsorbed either directly as SDA during this preparation step or, preferably, following desorption of a SDA. The external quantum efficiency (IPCE) could thereby be increased significantly. Particular emphasis was laid on dye molecules that absorb in the red part of the visible spectrum. Model experiments under ultrahigh vacuum (UHV) conditions with dye molecules adsorbed on defined crystal planes of single crystals aimed at a deeper understanding of the coupling of the chromophore electronic π-system within molecular aggregates and to the semiconductor surface. Detailed photoelectrochemical kinetic measurements were used to characterize and optimize the electrochemically prepared dye-sensitized ZnO films. Parallel electrical characterization in vacuum served to distinguish between contributions of charge transport within the ZnO semiconductor matrix and the ions of the electrolyte in the pore system of the electrode.

  19. FY 1980 Report on Dye Laser Materials

    DTIC Science & Technology

    1981-02-01

    by block number) Dye Lasers Laser Dyes Tunable Lasers Photodegradation Rhodamine Dyes 20. ABSTRACT (Continue n resld* it necesiry and Identify by block...limited usefulness as a portable military device because of the photodegradation of the dye solution. Although there have been state-of-the-art reviews...on laser dyes , 1𔃼 the photodegradation of laser dyes ,3 and dye lasers, 4- 6 only authors from, or funded by, military organizations have given strict

  20. Reuse of reactive dyes for dyeing of jute fabric.

    PubMed

    Chattopadhyay, S N; Pan, N C; Day, A

    2006-01-01

    The aim of the work was to find out suitable method of dyeing so that costly reactive dye can be reused without draining them. The bleached jute fabric was dyed with four different class of reactive dyes namely, cold brand, hot brand, vinyl sulphone and high exhaustion (HE) brand. It is found that the two-step two-bath method of reactive dyeing, where exhaustion and fixation step is separated, is most ideal for reuse of dye bath. Separate original samples produced K/S value same as that of original sample and the K/S value of separate reuse sample varied from 50% to 80% of the original sample depending on the class of dye. In case of same bath method, colour yield of original reuse samples varies from only 10% to maximum 30% of the original samples depending on the class of dyes. Reuse of reactive dyes following separate bath method is particularly suitable for higher depth of shade (4% and above). This process not only utilises costly reactive dyes to the maximum extent but it also produces low water pollution as the effluent contain minimum amount of dye. So the process is economic and eco-friendly as well.

  1. Photoactive dye enhanced tissue ablation for endoscopic laser prostatectomy

    NASA Astrophysics Data System (ADS)

    Ahn, Minwoo; Nguyen, Trung Hau; Nguyen, Van Phuc; Oh, Junghwan; Kang, Hyun Wook

    2015-02-01

    Laser light has been widely used as a surgical tool to treat benign prostate hyperplasia with high laser power. The purpose of this study was to validate the feasibility of photoactive dye injection to enhance light absorption and eventually to facilitate tissue ablation with low laser power. The experiment was implemented on chicken breast due to minimal optical absorption Amaranth (AR), black dye (BD), hemoglobin powder (HP), and endoscopic marker (EM), were selected and tested in vitro with a customized 532-nm laser system with radiant exposure ranging from 0.9 to 3.9 J/cm2. Light absorbance and ablation threshold were measured with UV-VIS spectrometer and Probit analysis, respectively, and compared to feature the function of the injected dyes. Ablation performance with dye-injection was evaluated in light of radiant exposure, dye concentration, and number of injection. Higher light absorption by injected dyes led to lower ablation threshold as well as more efficient tissue removal in the order of AR, BD, HP, and EM. Regardless of the injected dyes, ablation efficiency principally increased with input parameter. Among the dyes, AR created the highest ablation rate of 44.2+/-0.2 μm/pulse due to higher absorbance and lower ablation threshold. Preliminary tests on canine prostate with a hydraulic injection system demonstrated that 80 W with dye injection yielded comparable ablation efficiency to 120 W with no injection, indicating 33 % reduced laser power with almost equivalent performance. In-depth comprehension on photoactive dye-enhanced tissue ablation can help accomplish efficient and safe laser treatment for BPH with low power application.

  2. Chalcogenopyrylium Dyes with Anchors to Nanoparticle and Semiconductor Surfaces

    NASA Astrophysics Data System (ADS)

    Bedics, Matthew Allen

    Surface enhanced Raman scattering (SERS) has gained widespread attention as a biomedical imaging technique due to its multiplexing capabilities and the low limits of detection (LODs) of SERS-nanoprobes. The library of available reporter molecules, which are used to generate unique SERS spectra, was previously limited to commercially available dyes or a small group of cyanine reporters. Herein, the design and synthesis of a novel group of chalcogenopyrylium SERS reporters is described. These dyes have a high affinity for Au and absorption maxima that range into the NIR region. These reporter molecules enabled the use of the 1280 nm laser, which was previously incompatible with SERS imaging. Also, nanoprobe LODs using these dyes as reporters are lower than any previously documented systems, with a 100 aM LOD using a 785 nm excitation and multiple examples of fM to pM LODs using a 1064 nm or 1280 nm excitation source. Nanoprobes functionalized with these compounds have also been successfully utilized in vivo, and produce more intense SERS spectra as compared to a commonly used cyanine reporter. Dye sensitized solar cells (DSSCs) have produced considerable interest as an alternative to conventionally used Si-based solar cells. Specifically, DSSCs that use metal-free organic dyes as sensitizers are important due to the lower cost and the use of earth abundant materials as starting materials. Herein, a group of chalcogenopyrylium dyes were appended with an anchoring group to TiO2, which enables the use of these dyes as sensitizers. Structural modifications were used to extend absorption maxima into the near-infrared region of the light spectrum and to evaluate the effect that dye aggregation has on device performance. The monomethine dyes successfully produced a photocurrent, with incident photon to current efficiency values as high as 20%. Aggregation was found to benefit these systems due to the spectral broadening of aggregated dyes, and consequent increased range of

  3. Graphene-Embedded Hydrogel Nanofibers for Detection and Removal of Aqueous-Phase Dyes.

    PubMed

    Im, Kyungun; Nguyen, Duong Nguyen; Kim, Saerona; Kong, Hye Jeong; Kim, Yukyung; Park, Chul Soon; Kwon, Oh Seok; Yoon, Hyeonseok

    2017-03-16

    A facile route to graphene/polymer hydrogel nanofibers was developed. An aqueous dispersion of graphene (containing >40% bilayer graphene flakes) stabilized by a functionalized water-soluble polymer with phenyl side chains was successfully electrospun to yield nanofibers. Subsequent vapor-phase cross-linking of the nanofibers produced graphene-embedded hydrogel nanofibers (GHNFs). Interestingly, the GHNFs showed chemical sensitivity to the cationic dyes methylene blue (MB) and crystal violet (CV) in the aqueous phase. The adsorption capacities were as high as 0.43 and 0.33 mmol g(-1) s(-1) for MB and CV, respectively, even in a 1.5 mL s(-1) flow system. A density functional theory calculation revealed that aqueous-phase MB and CV dyes were oriented parallel to the graphene surface and that the graphene/dye ensembles were stabilized by secondary physical bonding mechanisms such as the π-π stacking interaction in an aqueous medium. The GHNFs exhibited electrochemical properties arising mainly from the electric double-layer capacitance, which were applied in a demonstration of GHNF-based membrane electrodes (5 cm in diameter) for detecting the dyes in the flow system. It is believed that the GHNF membrane can be a successful model candidate for commercialization of graphene due to its easy-to-fabricate process and remarkable properties.

  4. Metal-free organic dyes for dye-sensitized solar cells: from structure: property relationships to design rules.

    PubMed

    Mishra, Amaresh; Fischer, Markus K R; Bäuerle, Peter

    2009-01-01

    Dye-sensitized solar cells (DSSC) have attracted considerable attention in recent years as they offer the possibility of low-cost conversion of photovoltaic energy. This Review focuses on recent advances in molecular design and technological aspects of metal-free organic dyes for applications in dye-sensitized solar cells. Special attention has been paid to the design principles of these dyes and on the effect of various electrolyte systems. Cosensitization, an emerging technique to extend the absorption range, is also discussed as a way to improve the performance of the device. In addition, we report on inverted dyes for photocathodes, which constitutes a relatively new approach for the production of tandem cells. Special consideration has been paid to the correlation between the molecular structure and physical properties to their performance in DSSCs.

  5. Biological decolorization of dye solution containing malachite green by Pandoraea pulmonicola YC32 using a batch and continuous system.

    PubMed

    Chen, Chih-Yu; Kuo, Jong-Tar; Cheng, Chiu-Yu; Huang, Yu-Tang; Ho, I-Hsin; Chung, Ying-Chien

    2009-12-30

    In our study, we have isolated a relatively newly identified bacteria species, Pandoraea pulmonicola YC32, and first assessed its capability to treat malachite green (MG). The effects of various factors on decolorization efficiency were investigated in a batch system. The decolorization efficiency was found to be optimal within a pH of 7-10 and it increased, with increasing initial MG concentration up to 100 mg/l. The relationship between the decolorization rate and MG concentration agreed with Lineweaver-Burk equation. The apparent kinetic parameters, R(MG,max) and K(m), were 6.23 mg-MG/g-cell/h and 153.4 mg/l, respectively. The initial step in the biodegradation pathway of MG by P. pulmonicola YC32 was a reduction or N-demethylation reaction. We achieved a decolorization efficiency of 85.2% with 50mg/l MG in the immobilized P. pulmonicola YC32 continuous column system. This is the first report on the application of a continuous column system to decolorize MG using a microorganism.

  6. Electromagnetic antenna modeling (EAM) system

    NASA Astrophysics Data System (ADS)

    Packer, Malcolm; Powers, Robert; Tsitsopoulos, Paul

    1994-12-01

    The determination of foreign communications capabilities and intent is an important assessment function performed by the USAF National Air Intelligence Center (NAIC). In this context, Rome Laboratory became the NAIC engineering agent for the development of an NAIC requirement for the rapid analysis and evaluation of antenna structures based on often vague to sometimes detailed dimensional information. To this end, the Rome Laboratory sponsored development of the Electromagnetic Antenna Modeling (EAM) System, a state-of-the-art Pascal program with an MS Windows graphical user interface (GUI) pre- and post-processor. Users of NAIC capabilities initiate antenna analysis efforts that range from simple parametric studies to more complex, detailed antenna design and communication-system evaluations. Accordingly, EAM provides a modeling capability 'matched' to the sophistication of the individual analyst, with features appropriate for users ranging from nontechnical analysts to experienced antenna engineers. This capability is particularly valuable in the military-intelligence environment, in which high-speed assessments are required. In particular, EAM meets the specific antenna-analysis requirements of NAIC with a versatile graphical user interface.

  7. National Energy Modeling System (NEMS)

    DOE Data Explorer

    The National Energy Modeling System (NEMS) is a computer-based, energy-economy modeling system of U.S. through 2030. NEMS projects the production, imports, conversion, consumption, and prices of energy, subject to assumptions on macroeconomic and financial factors, world energy markets, resource availability and costs, behavioral and technological choice criteria, cost and performance characteristics of energy technologies, and demographics. NEMS was designed and implemented by the Energy Information Administration (EIA) of the U.S. Department of Energy (DOE). NEMS can be used to analyze the effects of existing and proposed government laws and regulations related to energy production and use; the potential impact of new and advanced energy production, conversion, and consumption technologies; the impact and cost of greenhouse gas control; the impact of increased use of renewable energy sources; and the potential savings from increased efficiency of energy use; and the impact of regulations on the use of alternative or reformulated fuels. NEMS has also been used for a number of special analyses at the request of the Administration, U.S. Congress, other offices of DOE and other government agencies, who specify the scenarios and assumptions for the analysis. Modules allow analyses to be conducted in energy topic areas such as residential demand, industrial demand, electricity market, oil and gas supply, renewable fuels, etc.

  8. An ultrastructural analysis of endothelial change paralleling platelet aggregation in a light/dye model of microvascular insult.

    PubMed Central

    Povlishock, J. T.; Rosenblum, W. I.; Sholley, M. M.; Wei, E. P.

    1983-01-01

    Those microvascular endothelial events that parallel the evolution of platelet aggregation were evaluated in a well-controlled animal model. Cat pial microvessels were observed through a cranial window while local platelet aggregation was produced by intravenous injection of sodium fluorescein and simultaneous exposure of the pial vessels to light from a filtered mercury lamp that excited the fluorescein. The vessels were fixed in situ when the in vivo observations of a preselected vessel indicated early, intermediate, or advanced aggregation in that vessel. The preselected vessel was then harvested for ultrastructural study together with adjacent vessels from the illuminated field. These vessels and appropriate controls were compared in semiserial thin sections. The onset of platelet aggregation in both venules and arterioles was accompanied by focal endothelial lucency, vacuole formation, luminal membrane rupture, and swelling of the nuclear envelope. These changes were not found in control material. With intermediate aggregation these changes were more common, while with advanced aggregation these abnormalities occurred together with focal endothelial denudation. Thus, in this model denudation occurred only with advanced aggregation and was not a prerequisite for aggregation. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 PMID:6824062

  9. Triphenylamine-based organic dyes with julolidine as the secondary electron donor for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Wu, Guohua; Kong, Fantai; Li, Jingzhe; Fang, Xiaqin; Li, Yi; Dai, Songyuan; Chen, Qianqian; Zhang, Xianxi

    2013-12-01

    Two novel donor-donor-π-conjugated-acceptor (D-D-π-A) metal-free organic dyes (JTPA1 and JTPA2) with a julolidine moiety as the secondary electron donor for dye-sensitized solar cells (DSSCs) are synthesized. Their absorption spectra, electrochemical and photovoltaic properties are extensively investigated and compared with TPA2 dye. Transient absorption measurements show that both sensitizers are quickly regenerated and the dye cations are efficiently intercepted by the redox mediator. Both dyes show good performance as DSSC photosensitizers. In particular, a DSSC using JTPA2 with rhodanine-3-acetic acid shows better photovoltaic performance with a short-circuit photocurrent density (Jsc) of 9.30 mA cm-2, an open-circuit photovoltage (Voc) of 509 mV and a fill factor (FF) of 0.68, corresponding to an overall conversion efficiency (η) of 3.2% under AM 1.5 irradiation (100 mW cm-2). Under similar test conditions, ruthenium-based N719 dye gives an efficiency of 6.7%. Compared to TPA2, the dye regeneration rate, the short-circuit photocurrent density and the conversion efficiency of JTPA2 are doubled by introducing a julolidine unit. Our findings show that the julolidine unit may be an excellent electron donor system for organic dyes harvesting solar irradiation.

  10. Preparation of highly selective solid-phase extractants for Cibacron reactive dyes using molecularly imprinted polymers.

    PubMed

    Al-Degs, Yahya S; Abu-Surrah, Adnan S; Ibrahim, Khalid A

    2009-02-01

    Selective polymeric extractants were prepared for preconcentration of Cibacron reactive red dye, a dye that is often applied with Cibacron reactive blue and Cibacron reactive yellow for dyeing of fabrics. The best extractant was fabricated (in chloroform) using methacrylic acid (as monomer), ethylene glycol dimethacrylate (as crosslinker), AIBN (as initiator for polymerization), and red dye as template molecule, with a molar stoichiometric ratio of 8.0:40.0:2.5:0.63, respectively. The structure of the molecularly imprinted polymer (MIP) was robust, and resisted dissolution up to 260 degrees C. Compared with the un-imprinted polymer, the imprinted product has a large specific surface area which improved its adsorption capacity. The effect of imprinting was obvious from the adsorption capacity measured at pH 4 for red dye (the imprinted molecule), which was increased from 24.0 to 79.3 mg g(-1) after imprinting. Equilibrium adsorption studies revealed that the dye-imprinted-polymer enables efficient extraction of red dye even in the presence of blue and yellow dyes which have similar chemical natures to the red dye. The selectivity coefficients S (red dye/dye), were 13.9 and 17.1 relative to the yellow and blue dyes, respectively. The MIP was found to be effective for red dye preconcentration, with a preconcentration factor of 100, from tap water and treated textile wastewater. The factors affecting extraction of red dye by the MIP were studied and optimized. Under the optimized extraction conditions, red dye was selectively quantified in the presence of other competing dyes at a concentration of 20 microg L(-1) from different water systems with satisfactory recoveries (91-95%) and RSD values (approximately 5.0%).

  11. Dry-spray deposition of TiO2 for a flexible dye-sensitized solar cell (DSSC) using a nanoparticle deposition system (NPDS).

    PubMed

    Kim, Min-Saeng; Chun, Doo-Man; Choi, Jung-Oh; Lee, Jong-Cheon; Kim, Yang Hee; Kim, Kwang-Su; Lee, Caroline Sunyong; Ahn, Sung-Hoon

    2012-04-01

    TiO2 powders were deposited on indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates for application to the photoelectrode of a dye-sensitized solar cell (DSSC). In the conventional DSSC manufacturing process, a semiconductor oxide such as TiO2 powder requires a sintering process at higher temperature than the glass transition temperature (T(g)) of polymers, and thus utilization of flexible polymer substrates in DSSC research has been constrained. To overcome this restriction related to sintering, we used a nanoparticle deposition system (NPDS) that could produce a thin coating layer through a dry-spray method under atmospheric pressure at room temperature. The powder was sprayed through a slit-type nozzle having a 0.4 x 10 mm2 rectangular outlet. In order to determine the deposited TiO2 thickness, five kinds of TiO2 layered specimens were prepared, where the specimens have single and double layer structures. Deposited powders on the ITO coated PET substrates were observed using FE-SEM and a scan profiler The thicker TiO2 photoelectrode with a DSSC having a double layer structure showed higher energy efficiency than the single layer case. The highest fabricated flexible DSSC displayed a short circuit current density J(sc) = 1.99 mA cm(-2), open circuit voltage V(oc) = 0.71 V, and energy efficiency eta = 0.94%. These results demonstrate the possibility of utilizing the dry-spray method to fabricate a TiO2 layer on flexible polymer substrates at room temperature under atmospheric pressure.

  12. Uptake of cationic dyes from aqueous solution by biosorption onto granular kohlrabi peel.

    PubMed

    Gong, Renmin; Zhang, Xiaoping; Liu, Huijun; Sun, Yingzhi; Liu, Birong

    2007-04-01

    A new, low cost, locally available biomaterial was tested for its ability to remove cationic dyes from aqueous solution. Granules prepared from kohlrabi peel had been utilized as a sorbent for uptake of three cationic dyes, methylene blue (MB), neutral red (NR) and acridine orange (AO). The effects of various experimental parameters (e.g., dye concentration, particle size, initial pH, contact time and other factors) were investigated and optimal experimental conditions were ascertained. Above the value of initial pH 4, three dyes studied could be removed effectively. The isothermal data fitted the Langmuir model in the case of NR sorption and the Freundlich model for all three dyes sorption. The biosorption processes followed the pseudo-first-order rate kinetics. The results in this study indicated that kohlrabi peel was an attractive candidate for removing cationic dyes from the dye wastewater.

  13. Efficiency enhancement of dye-sensitized solar cells (DSSC) by addition of synthetic dye into natural dye (anthocyanin)

    NASA Astrophysics Data System (ADS)

    Pratiwi, D. D.; Nurosyid, F.; Supriyanto, A.; Suryana, R.

    2017-02-01

    This article reported combination of anthocyanin and synthetic dyes in dye-sensitized solar cells (DSSC) applications. This study aims was to improve the performance of DSSC by addition of synthetic dye into anthocyanin dye. Anthocyanin dye was extracted from red cabbage and synthetic dye was obtained from N719. We prepared anthocyanin and synthetic dyes at 2 different volume, anthocyanin dye at volume of 10 ml and combination dyes with anthocyanin and synthetic dyes at volume of 8 mL : 2 mL. The DSSCs were designed into sandwich structure on the fluorine-doped tin oxide (FTO) substrates using TiO2 electrode, carbon electrode, anthocyanin and synthetic dyes, and redox electrolyte. The absorption wavelength of anthocyanin dye of red cabbage was 450 nm – 580 nm, the combination of anthocyanin and synthetic dyes can increase the absorbance peak only. The IPCE characteristic with anthocyanin dye of red cabbage and combination dyes resulted quantum efficiency of 0.081% and 0.092% at wavelength maximum about 430 nm. The DSSC by anthocyanin dye of red cabbage achieved a conversion efficiency of 0.024%, while the DSSC by combination dyes achieved a conversion efficiency of 0.054%, combination dyes by addition synthetic dye into anthocyanin dye enhanced the conversion efficiency up to 125%.

  14. The importance of dye chemistry and TiCl4 surface treatment in the behavior of Al2O3 recombination barrier layers deposited by atomic layer deposition in solid-state dye-sensitized solar cells.

    PubMed

    Brennan, Thomas P; Bakke, Jonathan R; Ding, I-Kang; Hardin, Brian E; Nguyen, William H; Mondal, Rajib; Bailie, Colin D; Margulis, George Y; Hoke, Eric T; Sellinger, Alan; McGehee, Michael D; Bent, Stacey F

    2012-09-21

    Atomic layer deposition (ALD) was used to fabricate Al(2)O(3) recombination barriers in solid-state dye-sensitized solar cells (ss-DSSCs) employing an organic hole transport material (HTM) for the first time. Al(2)O(3) recombination barriers of varying thickness were incorporated into efficient ss-DSSCs utilizing the Z907 dye adsorbed onto a 2 μm-thick nanoporous TiO(2) active layer and the HTM spiro-OMeTAD. The impact of Al(2)O(3) barriers was also studied in devices employing different dyes, with increased active layer thicknesses, and with substrates that did not undergo the TiCl(4) surface treatment. In all instances, electron lifetimes (as determined by transient photovoltage measurements) increased and dark current was suppressed after Al(2)O(3) deposition. However, only when the TiCl(4) treatment was eliminated did device efficiency increase; in all other instances efficiency decreased due to a drop in short-circuit current. These results are attributed in the former case to the similar effects of Al(2)O(3) ALD and the TiCl(4) surface treatment whereas the insulating properties of Al(2)O(3) hinder charge injection and lead to current loss in TiCl(4)-treated devices. The impact of Al(2)O(3) barrier layers was unaffected by doubling the active layer thickness or using an alternative ruthenium dye, but a metal-free donor-π-acceptor dye exhibited a much smaller decrease in current due to its higher excited state energy. We develop a model employing prior research on Al(2)O(3) growth and dye kinetics that successfully predicts the reduction in device current as a function of ALD cycles and is extendable to different dye-barrier systems.

  15. The effect of pulsewidth of pumping pulse on the stability of distributed feedback dye laser

    NASA Astrophysics Data System (ADS)

    Pasandideh, K.; Rahbari, M.; Sadighi Bonabi, R.

    2017-04-01

    The generation of a single and stable picosecond pulse by distributed feedback dye laser is investigated in this work. The numerical result for the rate equation system that includes the thermal effects in the lasing medium is provided. By applying this model to Rhodamine 6G, it is found that considerable improvement in the stability of the laser can be achieved by pumping the system with narrower laser pulses. The simulation shows that if the dye solution is pumped by sub-200 ps pulse, the laser can be operated in single-pulse output mode with acceptable stability in pulsewidth over a long range of pumping intensity. This result is confirmed by a more complicated model composed of non-averaged Maxwell and rate equations. Even though the thermal effects do not play a significant role in equivalent cavity lifetime, they result in considerable wavelength shift toward the shorter wavelengths.

  16. Identification of small-scale low and high permeability layers using single well forced-gradient tracer tests: fluorescent dye imaging and modelling at the laboratory-scale.

    PubMed

    Barns, Gareth L; Thornton, Steven F; Wilson, Ryan D

    2015-01-01

    Heterogeneity in aquifer permeability, which creates paths of varying mass flux and spatially complex contaminant plumes, can complicate the interpretation of contaminant fate and transport in groundwater. Identifying the location of high mass flux paths is critical for the reliable estimation of solute transport parameters and design of groundwater remediation schemes. Dipole flow tracer tests (DFTTs) and push-pull tests (PPTs) are single well forced-gradient tests which have been used at field-scale to estimate aquifer hydraulic and transport properties. In this study, the potential for PPTs and DFTTs to resolve the location of layered high- and low-permeability layers in granular porous media was investigated with a pseudo 2-D bench-scale aquifer model. Finite element fate and transport modelling was also undertaken to identify appropriate set-ups for in situ tests to determine the type, magnitude, location and extent of such layered permeability contrasts at the field-scale. The characteristics of flow patterns created during experiments were evaluated using fluorescent dye imaging and compared with the breakthrough behaviour of an inorganic conservative tracer. The experimental results show that tracer breakthrough during PPTs is not sensitive to minor permeability contrasts for conditions where there is no hydraulic gradient. In contrast, DFTTs are sensitive to the type and location of permeability contrasts in the host media and could potentially be used to establish the presence and location of high or low mass flux paths. Numerical modelling shows that the tracer peak breakthrough time and concentration in a DFTT is sensitive to the magnitude of the permeability contrast (defined as the permeability of the layer over the permeability of the bulk media) between values of 0.01-20. DFTTs are shown to be more sensitive to deducing variations in the contrast, location and size of aquifer layered permeability contrasts when a shorter central packer is used

  17. Optimization and modelling of synthetic azo dye wastewater treatment using Graphene oxide nanoplatelets: Characterization toxicity evaluation and optimization using Artificial Neural Network.

    PubMed

    Banerjee, Priya; Sau, Shubhra; Das, Papita; Mukhopadhayay, Aniruddha

    2015-09-01

    Azo dyes pose a major threat to current civilization by appearing in almost all streams of wastewater. The present investigation was carried out to examine the potential of Graphene oxide (GO) nanoplatelets as an efficient, cost-effective and non-toxic azo dye adsorbent for efficient wastewater treatment. The treatment process was optimized using Artificial Neural Network for maximum percentage dye removal and evaluated in terms of varying operational parameters, process kinetics and thermodynamics. A brief toxicity assay was also designed using fresh water snail Bellamya benghalensis to analyze the quality of the treated solution. 97.78% removal of safranin dye was obtained using GO as adsorbent. Characterization of GO nanoplatelets (using SEM, TEM, AFM and FTIR) reported the changes in its structure as well as surface morphology before and after use and explained its prospective as a good and environmentally benign adsorbent in very low quantities. The data recorded when subjected to different isotherms best fitted the Temkin isotherm. Further analysis revealed the process to be endothermic and chemisorption in nature. The verdict of the toxicity assay rendered the treated permeate as biologically safe for discharge or reuse in industrial and domestic purposes.

  18. Use of RSM modeling for optimizing decolorization of simulated textile wastewater by Pseudomonas aeruginosa strain ZM130 capable of simultaneous removal of reactive dyes and hexavalent chromium.

    PubMed

    Maqbool, Zahid; Hussain, Sabir; Ahmad, Tanvir; Nadeem, Habibullah; Imran, Muhammad; Khalid, Azeem; Abid, Muhammad; Martin-Laurent, Fabrice

    2016-06-01

    Remediation of colored wastewater loaded with dyes and metal ions is a matter of interest nowadays. In this study, 220 bacteria isolated from textile wastewater were tested for their potential to decolorize each of the four reactive dyes (reactive red-120, reactive black-5, reactive yellow-2, and reactive orange-16) in the presence of a mixture of four different heavy metals (Cr, Zn, Pb, Cd) commonly found in textile effluents. Among the tested bacteria, the isolate ZM130 was found to be the most efficient in decolorizing reactive dyes in the presence of the mixture of heavy metals and was identified as Pseudomonas aeruginosa strain ZM130 by 16S rRNA gene analysis. The strain ZM130 was highly effective in simultaneously removing hexavalent chromium (25 mg L(-1)) and the azo dyes (100 mg L(-1)) from the simulated wastewater even in the presence of other three heavy metals (Zn, Pb, Cd). Simultaneous removal of chromium and azo dyes ranged as 76.6-98.7 % and 51.9-91.1 %, respectively, after 180 h incubation. On the basis of quadratic polynomial equation and response surfaces given by the response surface methodology (RSM), optimal salt content, pH, carbon co-substrate content, and level of multi-metal mixtures for decolorization of reactive red-120 in a simulated textile wastewater by the strain ZM130 were predicted to be 19.8, 7.8, and 6.33 g L(-1) and a multi-metal mixture (Cr 13.10 mg L(-1), Pb 26.21 mg L(-1), Cd 13.10 mg L(-1), Zn 26.21 mg L(-1)), respectively. Moreover, the strain ZM130 also exhibited laccase and nicotinamide adenine dinucleotide (reduced)-dichlorophenolindophenol reductase (NADH-DCIP reductase) activity during the decolorization of reactive red-120. However, the laccase activity was found to be maximum in the presence of 300 mg L(-1) of the dye as compared to other concentrations. Hence, the isolation of this strain might serve as a potential bio-resource required for developing the strategies aiming at bioremediation of the

  19. Modeling solvatochromism of a quinolinium betaine dye in water solvent using sequential hybrid QM/MM and semicontinuum approach.

    PubMed

    Murugan, N Arul

    2011-02-10

    We have investigated the ambient temperature structure of 1-methyl-8-oxyquinolinium betaine (MOQB) in water solvent and compared to its gas-phase structure. We have employed Car-Parrinello molecular dynamics (CPMD) simulations within hybrid quantum mechanics-molecular mechanics (QM/MM) framework to study MOQB in water while CPMD technique has been used for the gas phase. We report significant solvent-induced geometrical changes in MOQB. The dipole moment of MOQB in water is 2 times larger than the gas-phase value. The average absorption spectra calculated from gas-phase configurations using Coulomb attenuated-B3LYP (CAMB3LYP) level of theory is comparable with experimental spectra reported in benzene (λ(max) = 590 nm), a nonpolar solvent. We have also computed the absorption spectra of MOQB in water solvent using continuum and semicontinuum solvent models. Based on this, we have calculated contributions from solvent-induced geometrical changes, hydrogen bonding, and intermolecular charge transfer to the solvatochromic shift and absorption spectra of MOQB in water. Absorption spectra calculations for MOQB in water with a semicontinuum approach for solvents using CAMB3LYP level of theory excellently reproduce the experimental spectra in water, where the theoretical λ(max) is 433 nm and the experimental λ(max) is around 440 nm.

  20. Modeling the Earth System, volume 3

    NASA Technical Reports Server (NTRS)

    Ojima, Dennis (Editor)

    1992-01-01

    The topics covered fall under the following headings: critical gaps in the Earth system conceptual framework; development needs for simplified models; and validating Earth system models and their subcomponents.

  1. Azaquinolone dye lasers

    DOEpatents

    Hammond, Peter R.; Atkins, Ronald L.; Henry, Ronald A.; Fletcher, Aaron N.

    1978-01-01

    A dye laser comprising a laser dye solution of a compound having the general structure: ##STR1## wherein at least one of the 5, 6 and 8 ring positions is occupied by a nitrogen atom in lieu of the corresponding CR group and X is OH, alkoxy, or amino including amino substituted by at least one of the following: alkyl, aryl, acyl, aracyl, a group which taken together with the nitrogen atom of the amino group forms a heterocyclic ring, or part of one or two 5 or 6 membered aliphatic heterocyclic rings attached to ring A at positions 6 or 8 or both depending on where the N in ring A is located. R.sub.1, R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.8 are hydrogen or other groups as defined below. The compounds lase in the blue to near ultraviolet region.

  2. Azacoumarin dye lasers

    DOEpatents

    Hammond, Peter R.; Atkins, Ronald L.; Henry, Ronald A.; Fletcher, Aaron N.

    1978-01-01

    A dye laser comprising a laser dye solution of a compound having the general structure: ##STR1## wherein at least one of the 5, 6 and 8 ring positions is occupied by a nitrogen atom in lieu of the corresponding CR group and X is OH, alkoxy, or amino including amino substituted by at least one of the following: alkyl, aryl, acyl, aracyl, a group which taken together with the nitrogen atom of the amino group forms a heterocyclic ring, or part of one or two 5 or 6 membered aliphatic heterocyclic rings attached to ring A at positions 6 or 8 or both depending on where the N in ring A is located. R.sub.3, R.sub.4, R.sub.5, R.sub.6 and R.sub.8 are hydrogen or other groups as defined below. The compounds lase in the blue-green to near ultraviolet region.

  3. Fiberized fluorescent dye microtubes

    NASA Astrophysics Data System (ADS)

    Vladev, Veselin; Eftimov, Tinko

    2013-03-01

    In the present work we study the effect of the length of fluorescent dye-filled micro-capillaries on the fluorescence spectra. Two types of micro-capillaries have been studied: a 100 μm inner diameter fused silica capillary with a transparent coating and one of the holes of a fiber optic glass ferrule with 125 μm inner diameter. The tubes were filled with solutions of Rhodamine 6G dissolved in ethanol and then in glycerin. Experimental data show that the maximum fluorescence and the largest spectral widths are observed for a sample length of about 0.25 mm for the used concentration. This results show that miniature tunable fiberized dye lasers can be developed using available standard micro-and fibre-optic components.

  4. Basic dye decomposition kinetics in a photocatalytic slurry reactor.

    PubMed

    Wu, Chun-Hsing; Chang, Hung-Wei; Chern, Jia-Ming

    2006-09-01

    Wastewater effluent from textile plants using various dyes is one of the major water pollutants to the environment. Traditional chemical, physical and biological processes for treating textile dye wastewaters have disadvantages such as high cost, energy waste and generating secondary pollution during the treatment process. The photocatalytic process using TiO2 semiconductor particles under UV light illumination has been shown to be potentially advantageous and applicable in the treatment of wastewater pollutants. In this study, the dye decomposition kinetics by nano-size TiO2 suspension at natural solution pH was experimentally studied by varying the agitation speed (50-200 rpm), TiO2 suspension concentration (0.25-1.71 g/L), initial dye concentration (10-50 ppm), temperature (10-50 degrees C), and UV power intensity (0-96 W). The experimental results show the agitation speed, varying from 50 to 200 rpm, has a slight influence on the dye decomposition rate and the pH history; the dye decomposition rate increases with the TiO2 suspension concentration up to 0.98 g/L, then decrease with increasing TiO2 suspension concentration; the initial dye decomposition rate increases with the initial dye concentration up to a certain value depending upon the temperature, then decreases with increasing initial dye concentration; the dye decomposition rate increases with the UV power intensity up to 64 W to reach a plateau. Kinetic models have been developed to fit the experimental kinetic data well.

  5. Coastal Modeling System (CMS) Users Manuel

    DTIC Science & Technology

    1992-08-01

    AD-A268 830 , INSTRUCTION REPORT CERC-91-1 COASTAL MODELING SYSTEM ( CMS ) USER’S MANUAL by Mary A. Cialone, David J. Mark, Lucia W. Chou, David A...THE COASTAL MODELING SYSTEM USER’S MANUAL Supplement 1 Issued August 1992 Enclosed are additions and corrections to the Coastal Modeling System ( CMS ...COVERED1 August 1992 Supplement I to September 1991 Manual 4. TITLE AND SUBTITLE S. FUNDING NUMBERS Coastal Modeling System ( CMS ) User’s Manual WU

  6. Using the Model Coupling Toolkit to couple earth system models

    USGS Publications Warehouse

    Warner, J.C.; Perlin, N.; Skyllingstad, E.D.

    2008-01-01

    Continued advances in computational resources are providing the opportunity to operate more sophisticated numerical models. Additionally, there is an increasing demand for multidisciplinary studies that include interactions between different physical processes. Therefore there is a strong desire to develop coupled modeling systems that utilize existing models and allow efficient data exchange and model control. The basic system would entail model "1" running on "M" processors and model "2" running on "N" processors, with efficient exchange of model fields at predetermined synchronization intervals. Here we demonstrate two coupled systems: the coupling of the ocean circulation model Regional Ocean Modeling System (ROMS) to the surface wave model Simulating WAves Nearshore (SWAN), and the coupling of ROMS to the atmospheric model Coupled Ocean Atmosphere Prediction System (COAMPS). Both coupled systems use the Model Coupling Toolkit (MCT) as a mechanism for operation control and inter-model distributed memory transfer of model variables. In this paper we describe requirements and other options for model coupling, explain the MCT library, ROMS, SWAN and COAMPS models, methods for grid decomposition and sparse matrix interpolation, and provide an example from each coupled system. Methods presented in this paper are clearly applicable for coupling of other types of models. ?? 2008 Elsevier Ltd. All rights reserved.

  7. Anaerobic/aerobic treatment of selected azo dyes in wastewater

    SciTech Connect

    Seshadri, S.; Bishop, P.L. . Dept. of Civil and Environmental Engineering); Agha, A.M. . Faculty of Civil Engineering)

    1994-01-01

    Azo dyes represent the largest class of dyes in use today. Current environmental concern with these dyes revolves around the potential carcinogenic health risk presented by these dyes or their intermediate biodegradation products when exposed to microflora in the human digestive tract. These dyes may build up in the environment, since many wastewater treatment plants allow these dyes to pass through the system virtually untreated. The initial step in the degradation of these dyes is the cleavage of the Azo bond. This cleavage is often impossible under aerobic conditions, but has been readily demonstrated under anaerobic conditions. The focus of the study was to determine the feasibility of using an anaerobic fluidized-bed reactor to accomplish this cleavage. The effects of typical process variables such as hydraulic retention time (HRT), influent dye concentration levels, and degree of bed fluidization on removal efficiencies were also studied. The four dyes selected for this study were Acid-Orange 7, Acid-Orange 8, Acid-Orange 10, and Acid-Red 14. The effectiveness of using a bench-scale-activated sludge reactor as a sequenced second stage was also examined. Results indicate that nearly complete cleavage of the Azo bond is easily accomplished for each of the four dyes under hydraulic retention times of either 12 or 24 h. Initial results indicate, though, that aromatic amine by-products remain. The sequenced second stage was able to remove the remaining Chemical Oxygen Demand (COD) load to acceptable levels. Work is presently underway to determine the face of the anaerobic by-products in the aerobic second stage.

  8. Photobleaching effect in azo-dye containing epoxy resin films: the potentiality of carbon nanotubes as azo-dye dispensers

    NASA Astrophysics Data System (ADS)

    Díaz Costanzo, Guadalupe; Goyanes, Silvia; Ledesma, Silvia

    2015-04-01

    Azo-dye molecules may suffer from bleaching under certain illumination conditions. When this photoinduced process occurs, it generates an irreversible effect that is characterized by the loss of absorption of the dye molecule. Moreover, the well-known isomerization of azodye molecules does not occur anymore. In this work it is shown how the addition of a small amount of multi-walled carbon nanotubes (MWCNTs) helps to decrease the bleaching effect in a photosensitive guest-host azo-polymer film. Two different systems were fabricated using an epoxy resin as polymer matrix. An azo-dye, Disperse Orange 3, was used as photosensitive material in both systems and MWCNTs were added into one of them. The optical response of the polymeric systems was studied considering the degree of photoinduced birefringence. Photobleaching of the azo-dye was observed in all cases however, the effect is lower for the composite material containing 0.2 wt % MWCNTs. The weak interaction between MWCNTs and dye molecules is less favorable when the material is heated. The optical behavior of the heated composite material suggests that carbon nanotubes can be potentially used as azo dye dispensers. The results are interpreted in terms of the non-covalent interaction between azo-dye molecules and MWCNTs.

  9. Modeling HE systems using DSD

    SciTech Connect

    Aslam, T.D.; Bdzil, J.B.

    1997-12-01

    As a high explosive (HE) ages, those properties of the HE dependent on its global energy-release rate (e.g. shock initiation and detonation propagation speed) are the most likely to be affected. Similarly, any HE replacement will bring with it changes in these same reaction rate dependent characteristics of the HE, in that the new material will not be identical to that being replaced. In this paper the authors describe how detonation shock dynamics (DSD) theory can be used to model how changes in the energy-release rate (as they are embodied in the HE`s detonation speed vs curvature relation) influence the speed of detonation propagation and in turn the performance of a system.

  10. Water system modeling for dispatcher training simulators

    SciTech Connect

    Rajagopal, S.; Sigari, P.G. ); Allen, J.E.; Assadian, M. )

    1993-08-01

    This paper addresses the existing need for training dispatchers in the operation of power systems where it involves managing large water systems. The problem formulation and implementation of water system modeling for the Dispatcher Training Simulators (DTS) are presented in this paper. The method systematically builds the water network descriptions. The model periodically calculates the water system flows, storage values, and currently available hydro generation capacities. The model is controllable by the instructor and provides the simulated telemetry of water system data to the control center functions in the DTS. The water system modeling enhances the power system modeling subsystem of the DTS. The method is validated on a large water system and power system data. The results and the benefits of water system modeling are discussed.

  11. Laser-induced reduction of a dye characterised by a high triplet-state yield and dissolved in a polymer

    SciTech Connect

    Sizykh, A G; Tarakanova, E A; Tatarinova, L L

    2000-01-31

    An investigation was made of the photoreduction kinetics of a dye in a solid polymer solution under the influence of laser radiation corresponding to the band of the first singlet - singlet transition. Participation of higher triplet states was considered in a model of the photoreduction of a dye characterised by a high intersystem crossing yield. An analytic solution was obtained for a system of kinetic equations. This solution takes into account the difference between the photoprocess rates. It is shown that a linear dependence of the effective dye-photoreduction rate on the laser radiation intensity can serve as a test of the participation of higher triplet states in the reaction. A comparison of the theoretical and experimental results obtained in the present study is used to determine the ratio of the photoreduction and deactivation rate constants of the higher triplet state of eosin K. (interaction of laser radiation with matter. laser plasma)

  12. Modeling of Spacecraft Advanced Chemical Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Benfield, Michael P. J.; Belcher, Jeremy A.

    2004-01-01

    This paper outlines the development of the Advanced Chemical Propulsion System (ACPS) model for Earth and Space Storable propellants. This model was developed by the System Technology Operation of SAIC-Huntsville for the NASA MSFC In-Space Propulsion Project Office. Each subsystem of the model is described. Selected model results will also be shown to demonstrate the model's ability to evaluate technology changes in chemical propulsion systems.

  13. Wastewater treatment: Dye and pigment industry. (Latest citations from the Selected Water Resources Abstracts database). Published Search

    SciTech Connect

    Not Available

    1993-03-01

    The bibliography contains citations concerning treatment of wastewater containing dyes and pigments. The citations discuss the of dyes and pigments in wastewater treatment systems, biodegradation of dyes, absorption and adsorption processes to remove dyes from wastewater, environmental effects from the disposal of dye-containing wastes, and methods of analysis for dyes in waste streams. Treatment methods such as ozonation, reverse osmosis, activated charcoal filtration, activated sludge, electrochemical treatments, thermal treatments, simple filtration, and absorption media are included. (Contains a minimum of 112 citations and includes a subject term index and title list.)

  14. Image analysis of dye stained patterns in soils

    NASA Astrophysics Data System (ADS)

    Bogner, Christina; Trancón y Widemann, Baltasar; Lange, Holger

    2013-04-01

    Quality of surface water and groundwater is directly affected by flow processes in the unsaturated zone. In general, it is difficult to measure or model water flow. Indeed, parametrization of hydrological models is problematic and often no unique solution exists. To visualise flow patterns in soils directly dye tracer studies can be done. These experiments provide images of stained soil profiles and their evaluation demands knowledge in hydrology as well as in image analysis and statistics. First, these photographs are converted to binary images classifying the pixels in dye stained and non-stained ones. Then, some feature extraction is necessary to discern relevant hydrological information. In our study we propose to use several index functions to extract different (ideally complementary) features. We associate each image row with a feature vector (i.e. a certain number of image function values) and use these features to cluster the image rows to identify similar image areas. Because images of stained profiles might have different reasonable clusterings, we calculate multiple consensus clusterings. An expert can explore these different solutions and base his/her interpretation of predominant flow mechanisms on quantitative (objective) criteria. The complete workflow from reading-in binary images to final clusterings has been implemented in the free R system, a language and environment for statistical computing. The calculation of image indices is part of our own package Indigo, manipulation of binary images, clustering and visualization of results are done using either build-in facilities in R, additional R packages or the LATEX system.

  15. New model systems for experimental evolution.

    PubMed

    Collins, Sinéad

    2013-07-01

    Microbial experimental evolution uses a few well-characterized model systems to answer fundamental questions about how evolution works. This special section highlights novel model systems for experimental evolution, with a focus on marine model systems that can be used to understand evolutionary responses to global change in the oceans.

  16. Towards low temperature sintering methods for dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Murali, Sukanya

    Access to economically viable renewable energy sources is essential for the development of a globally sustainable society. Solar energy has a large potential to satisfy the future need for renewable energy sources. Dye sensitized solar cells are a third generation of photovoltaic technologies with the potential for low cost environmentally safe energy production. Commercialization of this technology requires that dye sensitized solar cells with higher efficiencies can be fabricated on flexible substrates. The commonly used material for the anode in a Dye Sensitized Solar Cell consists of titanium dioxide nanoparticles covered with a layer of light sensitizing dye. For efficient electron transport throughout the nanoparticle network, good particle interconnections are necessary. For low temperature processing these interconnections can be achieved through a hydrothermal process. The focus of this research is to understand at a fundamental level this reaction-based sintering process. A titanium alkoxide precursor was mixed with commercial titania nanoparticles and coated on a transparent conductive oxide substrate. The product of the hydrolysis and condensation of the alkoxide served to connect the nanoparticles thus improving the electrical conduction of the titania electrode; this was confirmed by solar cell testing and electrochemical impedance spectroscopy. To further understand the formation of interconnections during reactive sintering, a model system based on inert silica particles was investigated. Titanium alkoxide precursor was mixed with commercial silica particles and reacted. Three different types of silica particles were used: each with a different morphology. The silica-titania multilayers/powders were characterized using SEM, XRD and BET. The efficiency of DSSCs is higher when larger non-porous silica particles are used and thin nanocrystalline titania is coated on this superstructure. This gave insight into the locations where the reactive liquid

  17. Selective adsorption and separation of organic dyes from aqueous solution on polydopamine microspheres.

    PubMed

    Fu, Jianwei; Xin, Qianqian; Wu, Xuechen; Chen, Zhonghui; Yan, Ya; Liu, Shujun; Wang, Minghuan; Xu, Qun

    2016-01-01

    Polydopamine (PDA) microspheres, synthesized by a facile oxidation polymerization route, were evaluated as a potential adsorbent for selective adsorption and separation of organic dyes. The adsorption processes towards nine water-soluble dyes (anionic dyes: methyl orange (MO), eosin-Y (EY), eosin-B (EB), acid chrome blue K (ACBK), neutral dye: neutral red (NR), and cationic dyes: rhodamine B (RhB), malachite green (MG), methylene blue (MB), safranine T (ST)) were thoroughly investigated. The adsorption selectivity of organic dyes onto PDA microspheres was successfully applied for the separation of dyes mixtures. Various influential factors such as solution pH, temperature, and contact time were employed to ascertain the optimal condition for adsorption of representative organic dyes including MB, MG and NR. The pseudo-first-order and pseudo-second-order kinetics models were used to fit the adsorption kinetics process. Five isothermal adsorption models (Langmuir, Dubnin-Radushkevich, Temkin, Freundlich and Harkins-Jura) were used to investigate the adsorption thermodynamics properties. The results showed that the PDA microspheres owned good selective adsorption ability towards cationic dyes. The adsorption kinetics process conformed to the pseudo-second-order kinetics model and the Langmuir isotherm model was more appropriate for tracing the adsorption behavior than other isotherm models. Thus, we can conclude PDA microspheres may be a high-efficiency selective adsorbent towards some cationic dyes.

  18. The CICT Earth Science Systems Analysis Model

    NASA Technical Reports Server (NTRS)

    Pell, Barney; Coughlan, Joe; Biegel, Bryan; Stevens, Ken; Hansson, Othar; Hayes, Jordan

    2004-01-01

    Contents include the following: Computing Information and Communications Technology (CICT) Systems Analysis. Our modeling approach: a 3-part schematic investment model of technology change, impact assessment and prioritization. A whirlwind tour of our model. Lessons learned.

  19. CONTROL SYSTEM IDENTIFICATION THROUGH MODEL MODULATION METHODS

    DTIC Science & Technology

    identification has been achieved by using model modulation techniques to drive dynamic models into correspondence with operating control systems. The system ... identification then proceeded from examination of the model and the adaptive loop. The model modulation techniques applied to adaptive control

  20. Cold Pad-Batch dyeing method for cotton fabric dyeing with reactive dyes using ultrasonic energy.

    PubMed

    Khatri, Zeeshan; Memon, Muhammad Hanif; Khatri, Awais; Tanwari, Anwaruddin

    2011-11-01

    Reactive dyes are vastly used in dyeing and printing of cotton fibre. These dyes have a distinctive reactive nature due to active groups which form covalent bonds with -OH groups of cotton through substitution and/or addition mechanism. Among many methods used for dyeing cotton with reactive dyes, the Cold Pad Batch (CPB) method is relatively more environment friendly due to high dye fixation and non requirement of thermal energy. The dyed fabric production rate is low due to requirement of at least twelve hours batching time for dye fixation. The proposed CPB method for dyeing cotton involves ultrasonic energy resulting into a one third decrease in batching time. The dyeing of cotton fibre was carried out with CI reactive red 195 and CI reactive black 5 by conventional and ultrasonic (US) method. The study showed that the use of ultrasonic energy not only shortens the batching time but the alkalis concentrations can considerably be reduced. In this case, the colour strength (K/S) and dye fixation (%F) also enhances without any adverse effect on colour fastness of the dyed fabric. The appearance of dyed fibre surface using scanning electron microscope (SEM) showed relative straightening of fibre convolutions and significant swelling of the fibre upon ultrasonic application. The total colour difference values ΔE (CMC) for the proposed method, were found within close proximity to the conventionally dyed sample.

  1. Dye-coated europium monosulfide

    SciTech Connect

    Kar, Srotoswini; Dollahon, Norman R.; Stoll, Sarah L.

    2011-05-15

    Nanoparticles of EuS were synthesized using europium dithiocarbamate complexes. The resulting nanoparticles were coated with the dye, 1-pyrene carboxylic acid and the resulting material was characterized using X-ray powder diffraction, TEM, and UV-visible spectroscopy. Fluorescence spectroscopy was used to determine the relative energy of the conduction band edge to the excited state energy of the dye. -- Graphical abstract: Dye sensitized magnetic semiconductor materials were prepared by synthesizing EuS nanoparticles using single source precursors and coating with the dye, 1-pyrene carboxylic acid. Display Omitted highlights: > Synthesized EuS nanoparticles, 11{+-}2.4 nm characterized using XRD, TEM, and UV-vis. spect. > Grafted a dye to the surface and characterized the product using XRD, FTIR, UV-vis., and TEM. > Studied the photophysical properties using fluorescence spectroscopy. > Determined the relative dye excited state to the conduction band of the semiconductor.

  2. Visual computing model for immune system and medical system.

    PubMed

    Gong, Tao; Cao, Xinxue; Xiong, Qin

    2015-01-01

    Natural immune system is an intelligent self-organizing and adaptive system, which has a variety of immune cells with different types of immune mechanisms. The mutual cooperation between the immune cells shows the intelligence of this immune system, and modeling this immune system has an important significance in medical science and engineering. In order to build a comprehensible model of this immune system for better understanding with the visualization method than the traditional mathematic model, a visual computing model of this immune system was proposed and also used to design a medical system with the immune system, in this paper. Some visual simulations of the immune system were made to test the visual effect. The experimental results of the simulations show that the visual modeling approach can provide a more effective way for analyzing this immune system than only the traditional mathematic equations.

  3. Next generation system modeling of NTR systems

    NASA Technical Reports Server (NTRS)

    Buksa, John J.; Rider, William J.

    1993-01-01

    The topics are presented in viewgraph form and include the following: nuclear thermal rocket (NTR) modeling challenges; current approaches; shortcomings of current analysis method; future needs; and present steps to these goals.

  4. Modeling Power Systems as Complex Adaptive Systems

    SciTech Connect

    Chassin, David P.; Malard, Joel M.; Posse, Christian; Gangopadhyaya, Asim; Lu, Ning; Katipamula, Srinivas; Mallow, J V.

    2004-12-30

    Physical analogs have shown considerable promise for understanding the behavior of complex adaptive systems, including macroeconomics, biological systems, social networks, and electric power markets. Many of today's most challenging technical and policy questions can be reduced to a distributed economic control problem. Indeed, economically based control of large-scale systems is founded on the conjecture that the price-based regulation (e.g., auctions, markets) results in an optimal allocation of resources and emergent optimal system control. This report explores the state-of-the-art physical analogs for understanding the behavior of some econophysical systems and deriving stable and robust control strategies for using them. We review and discuss applications of some analytic methods based on a thermodynamic metaphor, according to which the interplay between system entropy and conservation laws gives rise to intuitive and governing global properties of complex systems that cannot be otherwise understood. We apply these methods to the question of how power markets can be expected to behave under a variety of conditions.

  5. Model mount system for testing flutter

    NASA Technical Reports Server (NTRS)

    Farmer, M. G. (Inventor)

    1984-01-01

    A wind tunnel model mount system is disclosed for effectively and accurately determining the effects of attack and airstream velocity on a model airfoil or aircraft. The model mount system includes a rigid model attached to a splitter plate which is supported away from the wind tunnel wall several of flexible rods. Conventional instrumentation is employed to effect model rotation through a turntable and to record model flutter data as a function of the angle of attack versus dynamic pressure.

  6. A tunable dual frequency dye laser - dual frequency oscillator design

    NASA Technical Reports Server (NTRS)

    Abury, Y.

    1983-01-01

    The pulsed dye laser offers a tunable oscillator, followed by three amplifiers. It is pumped by a dual frequency Nd:YAG laser. Tuning and spectral width are controlled by a holographic network connected to a high power telescope. The modified two wavelength dye laser allows for absorption lidar techniques for remote sensing of the atmosphere. Line switching is achieved by electrooptical commutation. A feasibility experiment was performed with the original oscillator. A model was then built, and tested with different dyes. After a few modifications were made to improve the conversion efficiency, this oscillator was inserted in the laser to check whether the amplifier stages were correctly adjusted.

  7. On the performance of ruthenium dyes in dye sensitized solar cells: a free cluster approach based on theoretical indexes.

    PubMed

    Barrera, M; Crivelli, I; Loeb, B

    2016-05-01

    The performance of ruthenium dye sensitized solar cells (DSSC) with different types of ligand was studied by means of a theoretical model where the ruthenium complex is bound to two [Ti(OH)3](+) units, instead of the more usual cluster TiO2 model. Electron injection is proposed to proceed from a thermalized (3)MLCT state rather than from higher vibrational excited states. The efficiency of the dye linked to the two [Ti(OH)3](+) units was determined in terms of a global index (ξ), calculated as the product of three theoretical indexes (FI) built from the results of time-dependent density functional theory (TDDFT) calculations. The index considers the harvested and delivered energy (F1), the charge transferred to the semiconductor (F2), and dye regeneration (F3). The results show that this set of parameters is unique for each dye, and allows the comparative evaluation of the performance of a series of dyes, with a different ancillary ligand at each stage of the cell operation. The method provides insights that can help explain the improved performance of N3 and black dyes compared to other dyes.

  8. NASA's SPICE System Models the Solar System

    NASA Technical Reports Server (NTRS)

    Acton, Charles

    1996-01-01

    SPICE is NASA's multimission, multidiscipline information system for assembling, distributing, archiving, and accessing space science geometry and related data used by scientists and engineers for mission design and mission evaluation, detailed observation planning, mission operations, and science data analysis.

  9. Generic CSP Performance Model for NREL's System Advisor Model: Preprint

    SciTech Connect

    Wagner, M. J.; Zhu, G.

    2011-08-01

    The suite of concentrating solar power (CSP) modeling tools in NREL's System Advisor Model (SAM) includes technology performance models for parabolic troughs, power towers, and dish-Stirling systems. Each model provides the user with unique capabilities that are catered to typical design considerations seen in each technology. Since the scope of the various models is generally limited to common plant configurations, new CSP technologies, component geometries, and subsystem combinations can be difficult to model directly in the existing SAM technology models. To overcome the limitations imposed by representative CSP technology models, NREL has developed a 'Generic Solar System' (GSS) performance model for use in SAM. This paper discusses the formulation and performance considerations included in this model and verifies the model by comparing its results with more detailed models.

  10. Treatment of direct blending dye wastewater and recycling of dye sludge.

    PubMed

    Xu, Xin-Hui; Li, Ming-Li; Yuan, Yuan

    2012-03-06

    A new sorbent material, barium sulfate-Direct Blending Yellow D-3RNL hybrid (BSD), was synthesized and characterized by various methods. Both the anionic dyes, Reactive Brilliant Red X-3B and Weak Acid Green GS were hardly adsorbed by the BSD material, while the sorption of Ethyl Violet (EV) and Victoria Blue B were extremely obvious. The sorption of cationic dyes obeyed the Langmuir isotherm model, which depended on the electric charge attraction. The saturation amount of EV adsorbed onto the BSD material approached to 39.36 mg/g. The sorption of EV changed little with pH from 3 to 12 while it increased with increasing levels of electrolyte. A dye wastewater sampled from Jinjiang Chemicals was treated, and the color removal rate was more than the COD removal rate. In addition, the cationic dye-BSD sludge was utilized as a colorant fill-in coating. The light stability and thermal stability of the colorant was measured and exhibited good features. This work provided a simple and eco-friendly method for dye wastewater treatment with recycling of waste.

  11. High-value zeolitic material from bagasse fly ash: utilization for dye elimination.

    PubMed

    Shah, Bhavna A; Shah, Ajay V; Patel, Harendra D; Mistry, Chirag B

    2013-06-01

    Bagasse fly ash (BFA), a sugar industry waste, was used to prepare zeolitic material (ZFA) by means of alkaline hydrothermal treatment. ZFA showed improved morphology as a result of this treatment. The adsorption of the reactive dyes turquoise blue (TB) and brilliant magenta (BM), on both BFA and ZFA, was investigated in a batch contact system. A series of batch experiments revealed that optimal dye removal occurs at a 200 mg/L to 300 mg/L solute concentration, 60 minutes of agitation time, 5 g/L to 10 g/L adsorbent dose, a pH level of 2 to 4, and a temperature of 298 K. ZFA showed enhanced adsorption capacity as compared to BFA. According to the Langmuir equation, the maximum adsorption capacity was 12.66 mg/g and 45.45 mg/g for turquoise blue and brilliant magenta dyes, respectively, on BFA; and 21.74 mg/g and 100.00 mg/g for turquoise blue and brilliant magenta dyes, respectively, on ZFA. Kinetic studies showed that the correlation coefficients best fit with the pseudo-second-order kinetic model, confirming that the adsorption rate was controlled by a hemisorptions process.

  12. Particle Tracking Model (PTM) with Coastal Modeling System (CMS)

    DTIC Science & Technology

    2014-10-31

    System ( CMS ) 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER...www.erdc.usace.army.mil/Missions/WaterResources/CIRP.aspx Coastal Inlets Research Program Particle Tracking Model (PTM) with Coastal Modeling System ( CMS ) The...System ( CMS ), which provides coupled wave and current forcing for PTM simulations. CMS -PTM is implemented in the Surface-water Modeling System, a

  13. Synthesis and characterization of a Noble metal Enhanced Optical Nanohybrid (NEON): a high brightness detection platform based on a dye-doped silica nanoparticle.

    PubMed

    Roy, Shibsekhar; Dixit, Chandra K; Woolley, Robert; O'Kennedy, Richard; McDonagh, Colette

    2012-05-29

    A highly bright and photostable, fluorescent nanohybrid particle is presented which consists of gold nanoparticles (GNPs) embedded in dye-doped silica in a core-shell configuration. The dye used is the near-infrared emitting 4,5-benzo-5'-(iodoacetaminomethyl)-1',3,3,3',3'-pentamethyl-1-(4-sulfobutyl) indodicarbo cyanine. The nanohybrid architecture comprises a GNP core which is separated from a layer of dye molecules by a 15 nm buffer layer and has an outer protective, undoped silica shell. Using this architecture, a brightness factor of 550 has been achieved compared to the free dye. This hybrid system, referred to as Noble metal Enhanced Optical Nanohybrid (NEON) in this paper, is the first nanohybrid construct to our knowledge which demonstrates such tunable fluorescence property. NEON has enhanced photostability compared to the free dye and compared to a control particle without GNPs. Furthermore, the NEON particle, when used as a fluorescent label in a model bioassay, shows improved performance over assays using a conventional single dye molecule label.

  14. Mixed titanium, silicon, and aluminum oxide nanostructures as novel adsorbent for removal of rhodamine 6G and methylene blue as cationic dyes from aqueous solution.

    PubMed

    Pal, Umapada; Sandoval, Alberto; Madrid, Sergio Isaac Uribe; Corro, Grisel; Sharma, Vivek; Mohanty, Paritosh

    2016-11-01

    Mixed oxide nanoparticles containing Ti, Si, and Al of 8-15 nm size range were synthesized using a combined sol-gel - hydrothermal method. Effects of composition on the structure, morphology, and optical properties of the nanoparticles were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), microRaman spectroscopy, and diffuse reflectance spectroscopy (DRS). Dye removal abilities of the nanoparticles from aqueous solutions were tested for different cationic dyes. While all the mixed oxide nanoparticles revealed high and fast adsorption of cationic dyes, the particles containing Ti and Si turned out to be the best. The adsorption kinetics and equilibrium adsorption behavior of the adsorbate - adsorbent systems could be well described by pseudo-second-order kinetics and Langmuir isotherm model, respectively. Estimated thermodynamic parameters revealed the adsorption process is spontaneous, driven mainly by the electrostatic force between the cationic dye molecules and negative charge at nanoparticle surface. Highest dye adsorption capacity (162.96 mg MB/g) of the mixed oxide nanostructures containing Ti and Si is associated to their high specific surface area, and the presence of surface Si-O(δ-) groups, in addition to the hydroxyl groups of amorphous titania. Mixed oxide nanoparticles containing 75% Ti and 25% Si seen to be the most efficient adsorbents for removing cationic dye molecules from wastewater.

  15. Investigation of lasing from dye doped plastics using flash lamp and Nd:YAG excitation.

    NASA Astrophysics Data System (ADS)

    Masters, Mark; de Armond, Mike; Reynolds, Clint; Suedhoff, Hans

    2006-05-01

    We present an investigation of organic dye doped plastics as a lasing medium. The host materials examined are poly(methyl methacrylate) [acrylic], epoxy, polyester and polyurethane. Various solvents are used to improve dye dispersion within the material. Two forms of excitation (flash lamp and frequency doubled Nd:YAG) are used. For the Nd:YAG pumped dye lasers, a disk of dye doped plastic is mounted in a housing to provide random orbital motion. The disk is within a Littmann configuration cavity. Each dye disk is tested for threshold, durability, power output, bandwidth, and tuning range. An end pumped cylinder is also explored. For the flash lamp pumped dye lasers two configurations are used: a traditional dye cylinder within an elliptical reflector and a hollow cylinder with the flash lamp within the hollow. A monolithic cavity for the flash lamp pumped system is investigated.

  16. Analysis hierarchical model for discrete event systems

    NASA Astrophysics Data System (ADS)

    Ciortea, E. M.

    2015-11-01

    The This paper presents the hierarchical model based on discrete event network for robotic systems. Based on the hierarchical approach, Petri network is analysed as a network of the highest conceptual level and the lowest level of local control. For modelling and control of complex robotic systems using extended Petri nets. Such a system is structured, controlled and analysed in this paper by using Visual Object Net ++ package that is relatively simple and easy to use, and the results are shown as representations easy to interpret. The hierarchical structure of the robotic system is implemented on computers analysed using specialized programs. Implementation of hierarchical model discrete event systems, as a real-time operating system on a computer network connected via a serial bus is possible, where each computer is dedicated to local and Petri model of a subsystem global robotic system. Since Petri models are simplified to apply general computers, analysis, modelling, complex manufacturing systems control can be achieved using Petri nets. Discrete event systems is a pragmatic tool for modelling industrial systems. For system modelling using Petri nets because we have our system where discrete event. To highlight the auxiliary time Petri model using transport stream divided into hierarchical levels and sections are analysed successively. Proposed robotic system simulation using timed Petri, offers the opportunity to view the robotic time. Application of goods or robotic and transmission times obtained by measuring spot is obtained graphics showing the average time for transport activity, using the parameters sets of finished products. individually.

  17. The Chemistry of Plant and Animal Dyes.

    ERIC Educational Resources Information Center

    Sequin-Frey, Margareta

    1981-01-01

    Provides a brief history of natural dyes. Chemical formulas are provided for flavonoids, luteolin, genistein, brazilin, tannins, terpenes, naphthoquinone, anthraquinone, and dyes with an alkaloid structure. Also discusses chemical background of different dye processes. (CS)

  18. Model-Based Prognostics of Hybrid Systems

    NASA Technical Reports Server (NTRS)

    Daigle, Matthew; Roychoudhury, Indranil; Bregon, Anibal

    2015-01-01

    Model-based prognostics has become a popular approach to solving the prognostics problem. However, almost all work has focused on prognostics of systems with continuous dynamics. In this paper, we extend the model-based prognostics framework to hybrid systems models that combine both continuous and discrete dynamics. In general, most systems are hybrid in nature, including those that combine physical processes with software. We generalize the model-based prognostics formulation to hybrid systems, and describe the challenges involved. We present a general approach for modeling hybrid systems, and overview methods for solving estimation and prediction in hybrid systems. As a case study, we consider the problem of conflict (i.e., loss of separation) prediction in the National Airspace System, in which the aircraft models are hybrid dynamical systems.

  19. Linear systems, and ARMA- and Fliess models

    NASA Astrophysics Data System (ADS)

    Lomadze, Vakhtang; Khurram Zafar, M.

    2010-10-01

    Linear (dynamical) systems are central objects of study (in linear system theory), and ARMA- and Fliess models are two very important classes of models that are used to represent them. This article is concerned with the question of what is a relation between them (in case of higher dimensions). It is shown that the category of linear systems, the 'weak' category of ARMA-models and the category of Fliess models are equivalent to each other.

  20. Comparison of Photovoltaic Models in the System Advisor Model: Preprint

    SciTech Connect

    Blair, N. J.; Dobos, A. P.; Gilman, P.

    2013-08-01

    The System Advisor Model (SAM) is free software developed by the National Renewable Energy Laboratory (NREL) for predicting the performance of renewable energy systems and analyzing the financial feasibility of residential, commercial, and utility-scale grid-connected projects. SAM offers several options for predicting the performance of photovoltaic (PV) systems. The model requires that the analyst choose from three PV system models, and depending on that choice, possibly choose from three module and two inverter component models. To obtain meaningful results from SAM, the analyst must be aware of the differences between the model options and their applicability to different modeling scenarios. This paper presents an overview the different PV model options and presents a comparison of results for a 200-kW system using different model options.

  1. The Nature of the Donor Motif in Acceptor-Bridge-Donor Dyes as an Influence in the Electron Photo-Injection Mechanism in DSSCs.

    PubMed

    Zarate, Ximena; Schott-Verdugo, Stephan; Rodriguez-Serrano, Angela; Schott, Eduardo

    2016-03-10

    The combination and balance of acceptor(A)-bridge-donor(D) architecture of molecules confer suitable attributes and/or properties to act as efficient light-harvesting and sensitizers in dye sensitized solar cells (DSSCs). An important process in a DSSC performance is the electron photoinjection (PI) mechanism which can take place either via type I (indirect), that consists in injecting from the excited state of the dye to the semiconductor, or type II (direct), where the PI is from the ground state of the dye to the semiconductor upon photoexcitation. Here, we present a computational study about the role of the donor motif in the PI mechanisms displayed from a family of 11 A-bridge-D structured dyes to a (TiO2)15 anatase cluster. To this end, different donor motifs (D1-D11) were evaluated while the A and bridge motifs remained the same. All the computations were carried out within the DFT framework, using the B3LYP, PW91, PBE, M06L and CAM-B3LYP functionals. The 6-31G(d) basis set was employed for nonmetallic atoms and the LANL2DZ pseudopotential for Ti atoms. The solvation effects were incorporated using the polarized continuum model (PCM) for acetonitrile. As benchmark systems, alizarin and naphthalenediol dyes were analyzed, as they are known to undergo Type I and Type II PI pathways in DSSCs, respectively. Donors in the studied family of dyes could influence to drive Type I or II PI since it was found that D2 could show some Type II PI route, showing a new absorption band, although with CAM-B3LYP this shows a very low oscillator strength, while the remaining dyes behave according to Type I photoinjectors. Finally, the photovoltaic parameters that govern the light absorption process were evaluated, as the use of these criteria could be applied to predict the efficiency of the studied dyes in DSSCs devices.

  2. Synthesis, photovoltaic performances and TD-DFT modeling of push-pull diacetylide platinum complexes in TiO2 based dye-sensitized solar cells.

    PubMed

    Gauthier, Sébastien; Caro, Bertrand; Robin-Le Guen, Françoise; Bhuvanesh, Nattamai; Gladysz, John A; Wojcik, Laurianne; Le Poul, Nicolas; Planchat, Aurélien; Pellegrin, Yann; Blart, Errol; Jacquemin, Denis; Odobel, Fabrice

    2014-08-07

    In this joint experimental-theoretical work, we present the synthesis and optical and electrochemical characterization of five new bis-acetylide platinum complex dyes end capped with diphenylpyranylidene moieties, as well as their performances in dye-sensitized solar cells (DSCs). Theoretical calculations relying on Time-Dependent Density Functional Theory (TD-DFT) and a range-separated hybrid show a very good match with experimental data and allow us to quantify the charge-transfer character of each compound. The photoconversion efficiency obtained reaches 4.7% for 8e (see TOC Graphic) with the tri-thiophene segment, which is among the highest efficiencies reported for platinum complexes in DSCs.

  3. Zinc ferrite nanoparticle as a magnetic catalyst: Synthesis and dye degradation

    SciTech Connect

    Mahmoodi, Niyaz Mohammad

    2013-10-15

    Graphical abstract: Photocatalytic degradation of Reactive Red 198 and Reactive Red 120 by the synthesized zinc ferrite nanoparticle. - Highlights: • Magnetic zinc ferrite nanoparticle was synthesized and characterized. • Photocatalytic dye degradation by magnetic nanoparticle was studied. • Formate, acetate and oxalate were detected as dominant dye degradation aliphatic intermediates. • Nitrate and sulfate ions were detected as mineralization products of dyes. • Zinc ferrite nanoparticle was an effective magnetic photocatalyst to degrade dyes. - Abstract: In this paper, magnetic zinc ferrite (ZnFe{sub 2}O{sub 4}) nanoparticle was synthesized and its photocatalytic dye degradation ability from colored wastewater was studied. Reactive Red 198 (RR198) and Reactive Red 120 (RR120) were used as model dyes. The characteristics of ZnFe{sub 2}O{sub 4} were investigated using Fourier transform infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Photocatalytic dye degradation by ZnFe{sub 2}O{sub 4} was studied by UV–vis spectrophotometer and ion chromatography (IC). The effects of ZnFe{sub 2}O{sub 4} dosage, initial dye concentration and salt on dye degradation were evaluated. Formate, acetate and oxalate anions were detected as dominant aliphatic intermediate. Inorganic anions (nitrate and sulfate anions) were detected as dye mineralization products. The results indicated that ZnFe{sub 2}O{sub 4} could be used as a magnetic photocatalyst to degrade dyes from colored wastewater.

  4. Dye adsorption of cotton fabric grafted with PPI dendrimers: Isotherm and kinetic studies.

    PubMed

    Salimpour Abkenar, Samera; Malek, Reza Mohammad Ali; Mazaheri, Firouzmehr

    2015-11-01

    In this research, the cotton fabrics grafted with two generations of the poly(propylene imine) dendrimers were applied to adsorb textile dyes from aqueous solutions. Direct Red 80 (anionic dye), Disperse Yellow 42 (nonionic dye) and Basic Blue 9 (cationic dye) were selected as model dyes. The effect of various experimental parameters such as initial concentration of dyes, charge of dyes molecule, salt and pH was investigated on the adsorption process. Furthermore, kinetics and equilibrium of the adsorption process on the grafted samples were studied. It was found that maximum adsorption of anionic and disperse dyes took place at around pH 3, while cationic dye could be adsorbed at around pH 11. The Langmuir equation was able to describe the mechanism of dyes adsorption. In addition, the second-order equation was found to be fit with the kinetics data. Interestingly, it seems that the dye adsorption of the grafted fabrics is strongly pH dependent.

  5. A model for plant lighting system selection

    NASA Technical Reports Server (NTRS)

    Ciolkosz, D. E.; Albright, L. D.; Sager, J. C.; Langhans, R. W.

    2002-01-01

    A decision model is presented that compares lighting systems for a plant growth scenario and chooses the most appropriate system from a given set of possible choices. The model utilizes a Multiple Attribute Utility Theory approach, and incorporates expert input and performance simulations to calculate a utility value for each lighting system being considered. The system with the highest utility is deemed the most appropriate system. The model was applied to a greenhouse scenario, and analyses were conducted to test the model's output for validity. Parameter variation indicates that the model performed as expected. Analysis of model output indicates that differences in utility among the candidate lighting systems were sufficiently large to give confidence that the model's order of selection was valid.

  6. Strategies for reducing dye aggregation in luminescent host-guest systems: Rhodamine 6G incorporated in new mesoporous sol-gel hosts

    NASA Astrophysics Data System (ADS)

    de Queiroz, Thiago B.; Botelho, Moema B. S.; De Boni, Leonardo; Eckert, Hellmut; de Camargo, Andrea S. S.

    2013-03-01

    Aiming at the design of new luminescent host-guest materials with minimized aggregation effects, two classes of sol-gel derived mesoporous materials were explored as hosts for Rhodamine 6G (Rh6G) dye: The first consists of pure (SiO2) and phenyl-modified silica (Ph0.17SiO1.915) xerogels, prepared via sol-gel reaction using an ionic liquid as catalytic agent. The second consists of mesoporous sodium aluminosilicate glasses with Si to Al ratio in the range of 6 ≤ Si/Al ≤ 9. Characterization through high resolution solid state NMR proved the successful obtention of the designed host matrices. Following Rh6G-loading in various concentrations, the resulting materials were characterized by their luminescence and excitation spectra, excited state lifetimes, and quantum yields. The dye doped silica xerogels presented high quantum yield values (up to 87%), with no substantial decrease in efficiency with increasing dye concentration. At suitable Rh6G contents, all the final materials presented laser action under 532 nm excitation from a Q-switched frequency doubled Nd:YAG laser. The phenyl silicate sample presents the highest laser photostability with a half-life of 6560 pulses, under 2 mJ/pulse pump power, and 10 Hz repetition rate. The laser experiments provided further insights on the photodegradation mechanisms of such organic species.

  7. Dye sensitized solar cells.

    PubMed

    Wei, Di

    2010-03-16

    Dye sensitized solar cell (DSSC) is the only solar cell that can offer both the flexibility and transparency. Its efficiency is comparable to amorphous silicon solar cells but with a much lower cost. This review not only covers the fundamentals of DSSC but also the related cutting-edge research and its development for industrial applications. Most recent research topics on DSSC, for example, applications of nanostructured TiO(2), ZnO electrodes, ionic liquid electrolytes, carbon nanotubes, graphene and solid state DSSC have all been included and discussed.

  8. Dye Sensitized Solar Cells

    PubMed Central

    Wei, Di

    2010-01-01

    Dye sensitized solar cell (DSSC) is the only solar cell that can offer both the flexibility and transparency. Its efficiency is comparable to amorphous silicon solar cells but with a much lower cost. This review not only covers the fundamentals of DSSC but also the related cutting-edge research and its development for industrial applications. Most recent research topics on DSSC, for example, applications of nanostructured TiO2, ZnO electrodes, ionic liquid electrolytes, carbon nanotubes, graphene and solid state DSSC have all been included and discussed. PMID:20480003

  9. Ultrasound for low temperature dyeing of wool with acid dye.

    PubMed

    Ferrero, F; Periolatto, M

    2012-05-01

    The possibility of reducing the temperature of conventional wool dyeing with an acid levelling dye using ultrasound was studied in order to reach exhaustion values comparable to those obtained with the standard procedure at 98 °C, obtaining dyed samples of good quality. The aim was to develop a laboratory method that could be transferred at industrial level, reducing both the energy consumption and fiber damage caused by the prolonged exposure to high temperature without the use of polluting auxiliary agents. Dyeings of wool fabrics were carried out in the temperature range between 60 °C and 80 °C using either mechanical or ultrasound agitation of the bath and coupling the two methods to compare the results. For each dyeing, the exhaustion curves of the dye bath were determined and the better results of dyeing kinetics were obtained with ultrasound coupled with mechanical stirring. Hence the corresponding half dyeing times, absorption rate constants according to Cegarra-Puente modified equation and ultrasonic efficiency were calculated in comparison with mechanical stirring alone. In the presence of ultrasound the absorption rate constants increased by at least 50%, at each temperature, confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound was ascribed to the pre-exponential factor of the Arrhenius equation. It was also shown that the effect of ultrasound at 60 °C was just on the dye bath, practically unaffecting the wool fiber surface, as confirmed by the results of SEM analysis. Finally, fastness tests to rubbing and domestic laundering yielded good values for samples dyed in ultrasound assisted process even at the lower temperature. These results suggest the possibility, thanks to the use of ultrasound, to obtain a well equalized dyeing on wool working yet at 60°C, a temperature process strongly lower than 98°C, currently used in industry

  10. Multiple system modelling of waste management.

    PubMed

    Eriksson, Ola; Bisaillon, Mattias

    2011-12-01

    Due to increased environmental awareness, planning and performance of waste management has become more and more complex. Therefore waste management has early been subject to different types of modelling. Another field with long experience of modelling and systems perspective is energy systems. The two modelling traditions have developed side by side, but so far there are very few attempts to combine them. Waste management systems can be linked together with energy systems through incineration plants. The models for waste management can be modelled on a quite detailed level whereas surrounding systems are modelled in a more simplistic way. This is a problem, as previous studies have shown that assumptions on the surrounding system often tend to be important for the conclusions. In this paper it is shown how two models, one for the district heating system (MARTES) and another one for the waste management system (ORWARE), can be linked together. The strengths and weaknesses with model linking are discussed when compared to simplistic assumptions on effects in the energy and waste management systems. It is concluded that the linking of models will provide a more complete, correct and credible picture of the consequences of different simultaneous changes in the systems. The linking procedure is easy to perform and also leads to activation of project partners. However, the simulation procedure is a bit more complicated and calls for the ability to run both models.

  11. Applying Modeling Tools to Ground System Procedures

    NASA Technical Reports Server (NTRS)

    Di Pasquale, Peter

    2012-01-01

    As part of a long-term effort to revitalize the Ground Systems (GS) Engineering Section practices, Systems Modeling Language (SysML) and Business Process Model and Notation (BPMN) have been used to model existing GS products and the procedures GS engineers use to produce them.

  12. Building a generalized distributed system model

    NASA Technical Reports Server (NTRS)

    Mukkamala, Ravi

    1991-01-01

    A number of topics related to building a generalized distributed system model are discussed. The effects of distributed database modeling on evaluation of transaction rollbacks, the measurement of effects of distributed database models on transaction availability measures, and a performance analysis of static locking in replicated distributed database systems are covered.

  13. Adaptive System Modeling for Spacecraft Simulation

    NASA Technical Reports Server (NTRS)

    Thomas, Justin

    2011-01-01

    This invention introduces a methodology and associated software tools for automatically learning spacecraft system models without any assumptions regarding system behavior. Data stream mining techniques were used to learn models for critical portions of the International Space Station (ISS) Electrical Power System (EPS). Evaluation on historical ISS telemetry data shows that adaptive system modeling reduces simulation error anywhere from 50 to 90 percent over existing approaches. The purpose of the methodology is to outline how someone can create accurate system models from sensor (telemetry) data. The purpose of the software is to support the methodology. The software provides analysis tools to design the adaptive models. The software also provides the algorithms to initially build system models and continuously update them from the latest streaming sensor data. The main strengths are as follows: Creates accurate spacecraft system models without in-depth system knowledge or any assumptions about system behavior. Automatically updates/calibrates system models using the latest streaming sensor data. Creates device specific models that capture the exact behavior of devices of the same type. Adapts to evolving systems. Can reduce computational complexity (faster simulations).

  14. Quantitative television fluoroangiography - the optical measurement of dye concentrations and estimation of retinal blood flow

    SciTech Connect

    Greene, M.; Thomas, A.L. Jr.

    1985-06-01

    The development of a system for the measurement of dye concentrations from single retinal vessels during retinal fluorescein angiography is presented and discussed. The system uses a fundus camera modified for TV viewing. Video gating techniques define the areas of the retina to be studied, and video peak detection yields dye concentrations from retinal vessels. The time course of dye concentration is presented and blood flow into the retina is estimated by a time of transit technique.

  15. Synthesis, Characterization, and Application of Gold Nanoparticles in Green Nanochemistry Dye-Sensitized Solar Cells

    DTIC Science & Technology

    2012-06-01

    integrated with anthocyanin-based, dye-sensitized solar cells . The hybrid system was found to enhance the photovoltaic output of the system...Synthesis, Characterization, and Application of Gold Nanoparticles in Green Nanochemistry Dye-Sensitized Solar Cells by Hailey E. Cramer...Nanochemistry Dye-Sensitized Solar Cells Hailey E. Cramer University of Delaware Mark H. Griep National Research Council Shashi P. Karna

  16. Modeling Kanban Processes in Systems Engineering

    DTIC Science & Technology

    2012-06-01

    Modeling Kanban Processes in Systems Engineering Richard Turner School of Systems and Enterprises Stevens Institute of Technology Hoboken, NJ...dingold@usc.edu, jolane@usc.edu Abstract—Systems engineering processes using pull scheduling methods ( kanban ) are being evaluated with hybrid...development projects incrementally evolve capabilities of existing systems and/or systems of systems. A kanban -based scheduling system was defined and

  17. Hydrothermal conversion of urban food waste to chars for removal of textile dyes from contaminated waters.

    PubMed

    Parshetti, Ganesh K; Chowdhury, Shamik; Balasubramanian, Rajasekhar

    2014-06-01

    Hydrothermal carbonization of urban food waste was carried out to prepare hydrochars for removal of Acridine Orange and Rhodamine 6G dyes from contaminated water. The chemical composition and microstructure properties of the synthesized hydrochars were investigated in details. Batch adsorption experiments revealed that hydrochars with lower degree of carbonization were more efficient in adsorption of dyes. Operational parameters such as pH and temperature had a strong influence on the dye uptake process. The adsorption equilibrium data showed excellent fit to the Langmuir isotherm. The pseudo-second-order kinetic model provided a better correlation for the experimental kinetic data in comparison to the pseudo-first-order kinetic model. Thermodynamic investigations suggested that dye adsorption onto hydrochars was spontaneous and endothermic. The mechanism of dye removal appears to be associated with physisorption. An artificial neural network (ANN)-based modelling was further carried out to predict the dye adsorption capacity of the hydrochars.

  18. Designing control system information models

    NASA Technical Reports Server (NTRS)

    Panin, K. I.; Zinchenko, V. P.

    1973-01-01

    Problems encountered in modeling information models are discussed, Data cover condition, functioning of the object of control, and the environment involved in the control. Other parameters needed for the model include: (1) information for forming an image of the real situation, (2) data for analyzing and evaluating an evolving situation, (3) planning actions, and (4) data for observing and evaluating the results of model realization.

  19. NASA Lewis Wind Tunnel Model Systems Criteria

    NASA Technical Reports Server (NTRS)

    Soeder, Ronald H.; Haller, Henry C.

    1994-01-01

    This report describes criteria for the design, analysis, quality assurance, and documentation of models or test articles that are to be tested in the aeropropulsion facilities at the NASA Lewis Research Center. The report presents three methods for computing model allowable stresses on the basis of the yield stress or ultimate stress, and it gives quality assurance criteria for models tested in Lewis' aeropropulsion facilities. Both customer-furnished model systems and in-house model systems are discussed. The functions of the facility manager, project engineer, operations engineer, research engineer, and facility electrical engineer are defined. The format for pretest meetings, prerun safety meetings, and the model criteria review are outlined Then, the format for the model systems report (a requirement for each model that is to be tested at NASA Lewis) is described, the engineers that are responsible for developing the model systems report are listed, and the time table for its delivery to the facility manager is given.

  20. Electronic Education System Model-2

    ERIC Educational Resources Information Center

    Güllü, Fatih; Kuusik, Rein; Laanpere, Mart

    2015-01-01

    In this study we presented new EES Model-2 extended from EES model for more productive implementation in e-learning process design and modelling in higher education. The most updates were related to uppermost instructional layer. We updated learning processes object of the layer for adaptation of educational process for young and old people,…

  1. Laser beam modeling in optical storage systems

    NASA Technical Reports Server (NTRS)

    Treptau, J. P.; Milster, T. D.; Flagello, D. G.

    1991-01-01

    A computer model has been developed that simulates light propagating through an optical data storage system. A model of a laser beam that originates at a laser diode, propagates through an optical system, interacts with a optical disk, reflects back from the optical disk into the system, and propagates to data and servo detectors is discussed.

  2. Network and adaptive system of systems modeling and analysis.

    SciTech Connect

    Lawton, Craig R.; Campbell, James E. Dr.; Anderson, Dennis James; Eddy, John P.

    2007-05-01

    This report documents the results of an LDRD program entitled ''Network and Adaptive System of Systems Modeling and Analysis'' that was conducted during FY 2005 and FY 2006. The purpose of this study was to determine and implement ways to incorporate network communications modeling into existing System of Systems (SoS) modeling capabilities. Current SoS modeling, particularly for the Future Combat Systems (FCS) program, is conducted under the assumption that communication between the various systems is always possible and occurs instantaneously. A more realistic representation of these communications allows for better, more accurate simulation results. The current approach to meeting this objective has been to use existing capabilities to model network hardware reliability and adding capabilities to use that information to model the impact on the sustainment supply chain and operational availability.

  3. World Energy Projection System Plus Model Documentation: Main Model

    EIA Publications

    2016-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Main Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  4. World Energy Projection System Plus Model Documentation: Greenhouse Gases Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Greenhouse Gases Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  5. World Energy Projection System Plus Model Documentation: Refinery Model

    EIA Publications

    2016-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Refinery Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  6. World Energy Projection System Plus Model Documentation: Electricity Model

    EIA Publications

    2017-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) World Electricity Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  7. World Energy Projection System Plus Model Documentation: Coal Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Coal Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  8. World Energy Projection System Plus Model Documentation: Industrial Model

    EIA Publications

    2016-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) World Industrial Model (WIM). It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  9. World Energy Projection System Plus Model Documentation: Residential Model

    EIA Publications

    2016-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Residential Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  10. World Energy Projection System Plus Model Documentation: Transportation Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) International Transportation model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  11. World Energy Projection System Plus Model Documentation: District Heat Model

    EIA Publications

    2017-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) District Heat Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  12. World Energy Projection System Plus Model Documentation: Natural Gas Model

    EIA Publications

    2011-01-01

    This report documents the objectives, analytical approach and development of the World Energy Projection System Plus (WEPS ) Natural Gas Model. It also catalogues and describes critical assumptions, computational methodology, parameter estimation techniques, and model source code.

  13. A review of NIR dyes in cancer targeting and imaging.

    PubMed

    Luo, Shenglin; Zhang, Erlong; Su, Yongping; Cheng, Tianmin; Shi, Chunmeng

    2011-10-01

    The development of multifunctional agents for simultaneous tumor targeting and near infrared (NIR) fluorescence imaging is expected to have significant impact on future personalized oncology owing to the very low tissue autofluorescence and high tissue penetration depth in the NIR spectrum window. Cancer NIR molecular imaging relies greatly on the development of stable, highly specific and sensitive molecular probes. Organic dyes have shown promising clinical implications as non-targeting agents for optical imaging in which indocyanine green has long been implemented in clinical use. Recently, significant progress has been made on the development of unique NIR dyes with tumor targeting properties. Current ongoing design strategies have overcome some of the limitations of conventional NIR organic dyes, such as poor hydrophilicity and photostability, low quantum yield, insufficient stability in biological system, low detection sensitivity, etc. This potential is further realized with the use of these NIR dyes or NIR dye-encapsulated nanoparticles by conjugation with tumor specific ligands (such as small molecules, peptides, proteins and antibodies) for tumor targeted imaging. Very recently, natively multifunctional NIR dyes that can preferentially accumulate in tumor cells without the need of chemical conjugation to tumor targeting ligands have been developed and these dyes have shown unique optical and pharmaceutical properties for biomedical imaging with superior signal-to-background contrast index. The main focus of this article is to provide a concise overview of newly developed NIR dyes and their potential applications in cancer targeting and imaging. The development of future multifunctional agents by combining targeting, imaging and even therapeutic routes will also be discussed. We believe these newly developed multifunctional NIR dyes will broaden current concept of tumor targeted imaging and hold promise to make an important contribution to the diagnosis

  14. Waste metal hydroxide sludge as adsorbent for a reactive dye.

    PubMed

    Santos, Sílvia C R; Vílar, Vítor J P; Boaventura, Rui A R

    2008-05-30

    An industrial waste sludge mainly composed by metal hydroxides was used as a low-cost adsorbent for removing a reactive textile dye (Remazol Brilliant Blue) in solution. Characterization of this waste material included chemical composition, pH(ZPC) determination, particle size distribution, physical textural properties and metals mobility under different pH conditions. Dye adsorption equilibrium isotherms were determined at 25 and 35 degrees C and pH of 4, 7 and 10 revealing reasonably fits to Langmuir and Freundlich models. At 25 degrees C and pH 7, Langmuir fit indicates a maximum adsorption capacity of 91.0mg/g. An adsorptive ion-exchange mechanism was identified from desorption studies. Batch kinetic experiments were also conducted at different initial dye concentration, temperature, adsorbent dosage and pH. A pseudo-second-order model showed good agreement with experimental data. LDF approximation model was used to estimate homogeneous solid diffusion coefficients and the effective pore diffusivities. Additionally, a simulated real effluent containing the selected dye, salts and dyeing auxiliary chemicals, was also used in equilibrium and kinetic experiments and the adsorption performance was compared with aqueous dye solutions.

  15. Dye laser traveling wave amplifier

    NASA Technical Reports Server (NTRS)

    Davidson, F.

    1983-01-01

    A flash lamp pumped dye laser suitable for use as an amplifier stage was developed. The desired output laser pulses are of nanosecond duration, tunable in center frequency, and of good optical quality. Its usefulness as a laser oscillator is emphasized, because it constitutes a compact, relatively efficient source of tunable dye laser light.

  16. PLGA nanoparticles from nano-emulsion templating as imaging agents: Versatile technology to obtain nanoparticles loaded with fluorescent dyes.

    PubMed

    Fornaguera, C; Feiner-Gracia, N; Calderó, G; García-Celma, M J; Solans, C

    2016-11-01

    The interest in polymeric nanoparticles as imaging systems for biomedical applications has increased notably in the last decades. In this work, PLGA nanoparticles, prepared from nano-emulsion templating, have been used to prepare novel fluorescent imaging agents. Two model fluorescent dyes were chosen and dissolved in the oil phase of the nano-emulsions together with PLGA. Nano-emulsions were prepared by the phase inversion composition (PIC) low-energy method. Fluorescent dye-loaded nanoparticles were obtained by solvent evaporation of nano-emulsion templates. PLGA nanoparticles loaded with the fluorescent dyes showed hydrodynamic radii lower than 40nm; markedly lower than those reported in previous studies. The small nanoparticle size was attributed to the nano-emulsification strategy used. PLGA nanoparticles showed negative surface charge and enough stability to be used for biomedical imaging purposes. Encapsulation efficiencies were higher than 99%, which was also attributed to the nano-emulsification approach as well as to the low solubility of the dyes in the aqueous component. Release kinetics of both fluorescent dyes from the nanoparticle dispersions was pH-independent and sustained. These results indicate that the dyes could remain encapsulated enough time to reach any organ and that the decrease of the pH produced during cell internalization by the endocytic route would not affect their release. Therefore, it can be assumed that these nanoparticles are appropriate as systemic imaging agents. In addition, in vitro toxicity tests showed that nanoparticles are non-cytotoxic. Consequently, it can be concluded that the preparation of PLGA nanoparticles from nano-emulsion templating represents a very versatile technology that enables obtaining biocompatible, biodegradable and safe imaging agents suitable for biomedical purposes.

  17. EXPOSURE ANALYSIS MODELING SYSTEM (EXAMS): USER MANUAL AND SYSTEM DOCUMENTATION

    EPA Science Inventory

    The Exposure Analysis Modeling System, first published in 1982 (EPA-600/3-82-023), provides interactive computer software for formulating aquatic ecosystem models and rapidly evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals - pesticides, ...

  18. Effects of Dye Structure in Dye Sensitized Solar Cells

    NASA Astrophysics Data System (ADS)

    Hoskins, Anna R.

    Dye sensitized solar cells (DSSCs) are photovoltaic devices that may compete with standard silicon solar cells due to their ease of construction and lower cost [32]. Ruthenium dye structures, such as N3 (Ru -- (4,4' -- dicarboxylic acid -- 2,2' -- bipyridine)2(NCS)2), have shown promise for collection efficiencies near silicon photovoltaic levels [20, 33]. DSSCs have not achieved the reproducibility and maximum efficiency of silicon solar cells [33, 34]. Altering ligands on the dye molecules may affect the energies of light that are absorbed by the DSSC. Photovoltaic testing, including current versus voltage tests, of DSSCs with both narrow band monochromated light sources and broadband (AM1.5 solar simulator) allows comparison between maximum efficiency, short-circuit current, open circuit voltage, and spectral response (SR) for the dye molecules. By studying how the efficiency and power output change with different dye structures, the nature of how to increase efficiency of the DSSC can be addressed. Conjugation length of the ligands in ruthenium dye molecules can be shown, through square-well and Huckel theory calculations, to have a role in changing the HOMO-LUMO gap of the molecules and the absorption of specific wavelengths of light by the DSSC. The efficiency, max power, short circuit current, open circuit voltage, and SR were all measured for the DSSCs at wavelengths from 350 nm to 690 nm using a monochromated light source. Measurements taken at 20 nm steps reveal trends in the photon acceptance for dye molecules that can be linked to the conjugation length of the ligands in the dye through the SR. The change in the SR centroid and UV-VIS measurements indicate a trend toward increasing optimal wavelength with increasing conjugation length in the dye molecules; however these trends are not as pronounced as theoretical calculations for the dyes. This difference in wavelength shift occurs due to the theoretical calculations accounting for only the ligands

  19. Antimicrobial dyes and mechanosensitive channels.

    PubMed

    Boulos, Ramiz A

    2013-08-01

    The search for new and effective antimicrobial agents has never been as important; however, since the discovery of antibiotics, exploring the antimicrobial activity of dyes has been forgotten. Antimicrobial dyes are an untapped resource and have the ability to potentially combat the spread of drug-resistant bacteria either alone or as antimicrobial adjuvants. The mechanosensitive ion channel of large conductance (MscL) is highly conserved and ubiquitous in bacterial species. There is evidence to suggest that at least one triphenylmethane dye acts through the highly conserved MscL channel and combining the two approaches of exploring the mechanism of action of other triphenylmethane dyes or antimicrobial dyes in general and the novel MscL target provides a new opportunity for further exploration.

  20. Fluorometric procedures for dye tracing

    USGS Publications Warehouse

    Wilson, James F.

    1968-01-01

    This manual describes the current fluorometric procedures used by the U.S. Geological Survey in dye tracer studies such as time of travel, dispersion, reaeration, and dilution-type discharge measurements. The advantages of dye tracing are (1) low detection and measurement limits and (2) simplicity and accuracy in measuring dye tracer concentrations using fluorometric techniques. The manual contains necessary background information about fluorescence, dyes, and fluorometers and a description of fluorometric operation and calibration procedures as a guide for laboratory and field use. The background information should be useful to anyone wishing to experiment with dyes, fluorometer components, or procedures different from those described. In addition, a brief section on aerial photography is included because of its possible use to supplement ground-level fluorometry.