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Sample records for single ultrafine multicomponent

  1. Modelling traffic-induced multicomponent ultrafine particles in urban street canyon compartments: Factors that inhibit mixing.

    Science.gov (United States)

    Zhong, Jian; Nikolova, Irina; Cai, Xiaoming; MacKenzie, A Rob; Harrison, Roy M

    2018-03-16

    This study implements a two-box model coupled with ultrafine particle (UFP) multicomponent microphysics for a compartmentalised street canyon. Canyon compartmentalisation can be described parsimoniously by three parameters relating to the features of the canyon and the atmospheric state outside the canyon, i.e. the heterogeneity coefficient, the vortex-to-vortex exchange velocity, and the box height ratio. The quasi-steady solutions for the two compartments represent a balance among emissions, microphysical aerosol dynamics (i.e. evaporation/condensation of semi-volatiles, SVOCs), and exchange processes, none of which is negligible. This coupled two-box model can capture significant contrasts in UFP number concentrations and a measure of the volatility of the multi-SVOC-particles in the lower and upper canyon. Modelled ground-level UFP number concentrations vary across nucleation, Aitken, and accumulation particle modes as well-defined monotonic functions of canyon compartmentalisation parameters. Compared with the two-box model, a classic one-box model (without canyon compartmentalisation) leads to underestimation of UFP number concentrations by several tens of percent typically. By quantifying the effects of canyon compartmentalisation, this study provides a framework for understanding how canyon geometry and the presence of street trees, street furniture, and architectural features interact with the large-scale atmospheric flow to determine ground-level pollutant concentrations. Copyright © 2018. Published by Elsevier Ltd.

  2. Equivalence of two models in single-phase multicomponent flow simulations

    KAUST Repository

    Wu, Yuanqing

    2016-02-28

    In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models.

  3. Quantitative studies of rhubarb using quantitative analysis of multicomponents by single marker and response surface methodology.

    Science.gov (United States)

    Sun, Jiachen; Wu, Yueting; Dong, Shengjie; Li, Xia; Gao, Wenyuan

    2017-10-01

    In this work, we developed a novel approach to evaluate the contents of bioactive components in rhubarb. The present method was based on the quantitative analysis of multicomponents by a single-marker and response surface methodology approaches. The quantitative analysis of multicomponents by a single-marker method based on high-performance liquid chromatography coupled with photodiode array detection was developed and applied to determine the contents of 12 bioactive components in rhubarb. No significant differences were found in the results from the quantitative analysis of multicomponents by a single-marker and the external standard method. In order to maximize the extraction of 12 bioactive compounds in rhubarb, the ultrasonic-assisted extraction conditions were obtained by the response surface methodology coupled with Box-Behnken design. According to the obtained results, we showed that the optimal conditions would be as follows: proportion of ethanol/water 74.39%, solvent-to-solid ratio 24.07:1 v/w, extraction time 51.13 min, and extraction temperature 63.61°C. The analytical scheme established in this research should be a reliable, convenient, and appropriate method for quantitative determination of bioactive compounds in rhubarb. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Hydrogen Separation by Natural Zeolite Composite Membranes: Single and Multicomponent Gas Transport

    Directory of Open Access Journals (Sweden)

    Afrooz Farjoo

    2017-10-01

    Full Text Available Single and multicomponent gas permeation tests were used to evaluate the performance of metal-supported clinoptilolite membranes. The efficiency of hydrogen separation from lower hydrocarbons (methane, ethane, and ethylene was studied within the temperature and pressure ranges of 25–600 °C and 110–160 kPa, respectively. The hydrogen separation factor was found to reduce noticeably in the gas mixture compared with single gas experiments at 25 °C. The difference between the single and multicomponent gas results decreased as the temperature increased to higher than 300 °C, which is when the competitive adsorption–diffusion mechanism was replaced by Knudsen diffusion or activated diffusion mechanisms. To evaluate the effect of gas adsorption, the zeolite surface isotherms of each gas in the mixture were obtained from 25 °C to 600 °C. The results indicated negligible adsorption of individual gases at temperatures higher than 300 °C. Increasing the feed pressure resulted in a higher separation efficiency for the individual gases compared with the multicomponent mixture, due to the governing effect of the adsorptive mechanism. This study provides valuable insight into the application of natural zeolites for the separation of hydrogen from a mixture of hydrocarbons.

  5. Inverse modeling of multicomponent reactive transport through single and dual porosity media

    Science.gov (United States)

    Samper, Javier; Zheng, Liange; Fernández, Ana María; Montenegro, Luis

    2008-06-01

    Compacted bentonite is foreseen as buffer material for high-level radioactive waste in deep geological repositories because it provides hydraulic isolation, chemical stability, and radionuclide sorption. A wide range of laboratory tests were performed within the framework of FEBEX ( Full-scale Engineered Barrier EXperiment) project to characterize buffer properties and develop numerical models for FEBEX bentonite. Here we present inverse single and dual-continuum multicomponent reactive transport models of a long-term permeation test performed on a 2.5 cm long sample of FEBEX bentonite. Initial saline bentonite porewater was flushed with 5.5 pore volumes of fresh granitic water. Water flux and chemical composition of effluent waters were monitored during almost 4 years. The model accounts for solute advection and diffusion and geochemical reactions such as aqueous complexation, acid-base, cation exchange, protonation/deprotonation by surface complexation and dissolution/precipitation of calcite, chalcedony and gypsum. All of these processes are assumed at local equilibrium. Similar to previous studies of bentonite porewater chemistry on batch systems which attest the relevance of protonation/deprotonation on buffering pH, our results confirm that protonation/deprotonation is a key process in maintaining a stable pH under dynamic transport conditions. Breakthrough curves of reactive species are more sensitive to initial porewater concentration than to effective diffusion coefficient. Optimum estimates of initial porewater chemistry of saturated compacted FEBEX bentonite are obtained by solving the inverse problem of multicomponent reactive transport. While the single-continuum model reproduces the trends of measured data for most chemical species, it fails to match properly the long tails of most breakthrough curves. Such limitation is overcome by resorting to a dual-continuum reactive transport model.

  6. [A new method of calibration and positioning in quantitative analysis of multicomponents by single marker].

    Science.gov (United States)

    He, Bing; Yang, Shi-Yan; Zhang, Yan

    2012-12-01

    This paper aims to establish a new method of calibration and positioning in quantitative analysis of multicomponents by single marker (QAMS), using Shuanghuanglian oral liquid as the research object. Establishing relative correction factors with reference chlorogenic acid to other 11 active components (neochlorogenic acid, cryptochlorogenic acid, cafferic acid, forsythoside A, scutellarin, isochlorogenic acid B, isochlorogenic acid A, isochlorogenic acid C, baicalin and phillyrin wogonoside) in Shuanghuanglian oral liquid by 3 correction methods (multipoint correction, slope correction and quantitative factor correction). At the same time chromatographic peak was positioned by linear regression method. Only one standard uas used to determine the content of 12 components in Shuanghuanglian oral liquid, in stead of needing too many reference substance in quality control. The results showed that within the linear ranges, no significant differences were found in the quantitative results of 12 active constituents in 3 batches of Shuanghuanglian oral liquid determined by 3 correction methods and external standard method (ESM) or standard curve method (SCM). And this method is simpler and quicker than literature methods. The results were accurate and reliable, and had good reproducibility. While the positioning chromatographic peaks by linear regression method was more accurate than relative retention time in literature. The slope and the quantitative factor correction controlling the quality of Chinese traditional medicine is feasible and accurate.

  7. Ultra-fine powders using glycine-nitrate combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Chick, L.A.; Pederson, L.R.; Bates, J.L.; Maupin, G.D.

    1991-05-01

    Fabrication of advanced, multifunctional materials frequently requires the synthesis of complex, ultra-fine powders comprised of a single phase containing several elements (multicomponent) or of several phases that are intimately mixed on a micro-scale (composite). A new combustion synthesis method, the glycine/nitrate process (GNP), is particularly useful for synthesizing ultra-fine, multicomponent oxide powders. Examples discussed include La(Sr)CrO{sub 3} and La(Sr)FeO{sub 3} perovskites and a composite of three phases, NiO, NiFe{sub 2}O{sub 4}, and Cu metal. The GNP consists of two basic steps. First, metal nitrates and a low molecular weight amino acid are dissolved in water. Second, the solution is boiled until it thickens. This viscous liquid ignites and undergoes self-sustaining combustion, producing an ash composed of the oxide product. Most refractory oxides that are composed of a combination of metals having stable nitrates should be possible to synthesize using GNP. 15 refs., 8 figs.

  8. Mechanical behavior of ultra-fine grained and nanocrystalline metals and single crystals: Experiments, modeling and simulations

    Science.gov (United States)

    Liu, Jian

    Ultra-fine grained (ufg, 100 nm viscoplastic phenomenological Khan--Liang--Farrokh (KLF) model is used to correlate the experimental results of the ufg/nc Ti. Crystal Plasticity Finite Element Method (CPFEM) with three different single crystal plasticity constitutive models is used for the purpose of incorporating strain rate and temperature effects into CPFEM. The classical and two newly developed single crystal plasticity models are used to simulate the deformation responses of single crystal aluminum. A constitutive model based on intragranular dislocation slip is shown to correlate closely to the stain rate effect and latent hardening behavior of single crystal Al. For ufg/nc face-centered cubic (FCC) material, we assume that dislocation slip is still the most important deformation mechanism while there is no interaction between dislocations within grains. We develop a constitutive model based on dislocation glide within ufg/nc grains and include all stages of dislocation activities especially their interactions with GB. An Arrhenius type rate is established based on the thermal activated depinning of dislocations from GB obstacles. The thermal strength is obtained as a function of the activation energy of the GB obstacles and the activation length. The athermal part includes the strength due to the grain size dependence and the strength due to the dislocation density. The model parameters for two ufg/nc materials are determined by comparing experimental results to the one dimensional (1D) flow stress model using a Taylor's factor. The new constitutive model is incorporated into three dimensional crystal plasticity and the crystal plasticity model is implemented into a UMAT subroutine of ABAQUS finite element program. The uniaxial deformation responses of two ufg/nc materials are simulated using the previously determined model parameters. CPFEM simulations give flow stress predictions that are very close to 1D model correlations/predictions. It is a clear

  9. Approximate non-linear multiparameter inversion for multicomponent single and double P-wave scattering in isotropic elastic media

    Science.gov (United States)

    Ouyang, Wei; Mao, Weijian

    2018-03-01

    An asymptotic quadratic true-amplitude inversion method for isotropic elastic P waves is proposed to invert medium parameters. The multicomponent P-wave scattered wavefield is computed based on a forward relationship using second-order Born approximation and corresponding high-frequency ray theoretical methods. Within the local double scattering mechanism, the P-wave transmission factors are elaborately calculated, which results in the radiation pattern for P-waves scattering being a quadratic combination of the density and Lamé's moduli perturbation parameters. We further express the elastic P-wave scattered wavefield in a form of generalized Radon transform (GRT). After introducing classical backprojection operators, we obtain an approximate solution of the inverse problem by solving a quadratic non-linear system. Numerical tests with synthetic data computed by finite-differences scheme demonstrate that our quadratic inversion can accurately invert perturbation parameters for strong perturbations, compared with the P-wave single-scattering linear inversion method. Although our inversion strategy here is only syncretized with P-wave scattering, it can be extended to invert multicomponent elastic data containing both P-wave and S-wave information.

  10. Single, binary and multi-component adsorption of some anions and heavy metals on environmentally friendly Carpobrotus edulis plant.

    Science.gov (United States)

    Chiban, Mohamed; Soudani, Amina; Sinan, Fouad; Persin, Michel

    2011-02-01

    A low-cost adsorbent and environmentally friendly adsorbent from Carpobrotus edulis plant was used for the removal of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions from single, binary and multi-component systems. The efficiency of the adsorbent was studied using batch adsorption technique under different experimental conditions by varying parameters such as pH, initial concentration and contact time. In single component systems, the dried C. edulis has the highest affinity for Pb(2+), followed by NO(3)(-), Cd(2+) and H(2)PO(4)(-), with adsorption capacities of 175mg/g, 125mg/g, 28mg/g and 26mg/g, respectively. These results showed that the adsorption of NO(3)(-) and H(2)PO(4)(-) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. Freundlich adsorption model, showed the best fit to the single and binary experimental adsorption data. These results also indicated that the adsorption yield of Pb(2+) ion was reduced by the presence of Cd(2+) ion in binary metal mixture. The competitive adsorption of NO(3)(-), H(2)PO(4)(-), Pb(2+) and Cd(2+) ions on dried C. edulis plant shows that NO(3)(-) and H(2)PO(4)(-) anions are able to adsorb on different free binding sites and Pb(2+) and Cd(2+) cations are able to adsorb on the same active sites of C. edulis particles. The dried C. edulis was found to be efficient in removing nitrate, phosphate, cadmium and lead from aqueous solution as compared to other adsorbents already used for the removal of these ions. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Biosorption of chromium, copper and zinc by wine-processing waste sludge: Single and multi-component system study

    International Nuclear Information System (INIS)

    Liu, Cheng-Chung; Wang, Ming-Kuang; Chiou, Chyow-San; Li, Yuan-Shen; Yang, Chia-Yi; Lin, Yu-An

    2009-01-01

    Wine-processing waste sludge (WPWS) has been shown to have powerful potential for sorption of some heavy metals (i.e., chromium, lead and nickel) in single-component aqueous solutions. But although most industrial wastewater contains two or more toxic metals, there are few sorption studies on multicomponent metals by WPWS. This study has two goals: (i) conduct competitive adsorption using Cr, Cu and Zn as sorbates and examine their interaction in binary or ternary systems; and (ii) determine the effects of temperature on the kinetic sorption reaction. The sludge tested contained a high amount of organic matter (38%) and had a high cation exchange capacity (CEC, 255 cmol c kg -1 ). Infrared analysis reveals that carboxyl is the main functional group in this WPWS. The 13 C NMR determination indicates alkyl-C and carboxyl-C are major organic functional groups. At steady state, there are about 40.4% (Cr), 35.0% (Cu) and 21.9% (Zn) sorbed in the initial 6.12 mM of single-component solutions. Only pseudo-second-order sorption kinetic model successfully describes the kinetics of sorption for all experimental metals. The rate constants, k 2 , of Cr, Cu and Zn in single-component solutions are 0.016, 0.030 and 0.154 g mg -1 min -1 , respectively. The sorption of metals by WPWS in this competitive system shows the trend: Cr > Cu > Zn. Ions of charge, hydrated radius and electronic configuration are main factors affecting sorption capacity. The least sorption for Zn in this competitive system can be attributed to its full orbital and largest hydrated radius. Though the effect of temperature on Zn sorption is insignificant, high temperature favors the other metallic sorptions, in particular for Cr. However, the Cr sorption is lower than Cu at 10 deg. C. The Cr sorption by WPWS can be higher than that of Cu at 30 deg. and 50 deg. C.

  12. Quantifying the Assembly of Multicomponent Molecular Machines by Single-Molecule Total Internal Reflection Fluorescence Microscopy.

    Science.gov (United States)

    Boehm, E M; Subramanyam, S; Ghoneim, M; Washington, M Todd; Spies, M

    2016-01-01

    Large, dynamic macromolecular complexes play essential roles in many cellular processes. Knowing how the components of these complexes associate with one another and undergo structural rearrangements is critical to understanding how they function. Single-molecule total internal reflection fluorescence (TIRF) microscopy is a powerful approach for addressing these fundamental issues. In this article, we first discuss single-molecule TIRF microscopes and strategies to immobilize and fluorescently label macromolecules. We then review the use of single-molecule TIRF microscopy to study the formation of binary macromolecular complexes using one-color imaging and inhibitors. We conclude with a discussion of the use of TIRF microscopy to examine the formation of higher-order (i.e., ternary) complexes using multicolor setups. The focus throughout this article is on experimental design, controls, data acquisition, and data analysis. We hope that single-molecule TIRF microscopy, which has largely been the province of specialists, will soon become as common in the tool box of biophysicists and biochemists as structural approaches have become today. © 2016 Elsevier Inc. All rights reserved.

  13. Scintillating screens based on the single crystalline films of multicomponent garnets: new achievements and possibilities

    Czech Academy of Sciences Publication Activity Database

    Zorenko, Yu.; Gorbenko, V.; Zorenko, T.; Paprocki, K.; Nikl, Martin; Mareš, Jiří A.; Bilski, P.; Twardak, A.; Sidletskiy, O.; Gerasymov, I.; Grinyov, B.; Fedorov, A.

    2016-01-01

    Roč. 63, č. 2 (2016), s. 497-502 ISSN 0018-9499 R&D Projects: GA ČR GAP204/12/0805 Institutional support: RVO:68378271 Keywords : Ce dopant * garnets * liquid phase epitaxy * luminescence * scintillators * single crystalline films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.171, year: 2016

  14. Contrasting single and multi-component working-memory systems in dual tasking

    NARCIS (Netherlands)

    Nijboer, Menno; Borst, Jelmer; van Rijn, Hedderik; Taatgen, Niels

    2016-01-01

    Working memory can be a major source of interference in dual tasking. However, there is no consensus on whether this interference is the result of a single working memory bottleneck, or of interactions between different working memory components that together form a complete working-memory system.

  15. Biosorption of chromium, copper and zinc by wine-processing waste sludge: Single and multi-component system study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Cheng-Chung [Department of Environmental Engineering, National Ilan University, Ilan, 260, Taiwan (China); Wang, Ming-Kuang, E-mail: mkwang@ntu.edu.tw [Department of Agricultural Chemistry, National Taiwan University, Taipei, 106, Taiwan (China); Chiou, Chyow-San; Li, Yuan-Shen [Department of Environmental Engineering, National Ilan University, Ilan, 260, Taiwan (China); Yang, Chia-Yi [Department of Chemical and Materials Engineering, Tamkang University, Tamsui, 251, Taiwan (China); Lin, Yu-An [Department of Animal Science, National Ilan University, Ilan, 260, Taiwan (China)

    2009-11-15

    Wine-processing waste sludge (WPWS) has been shown to have powerful potential for sorption of some heavy metals (i.e., chromium, lead and nickel) in single-component aqueous solutions. But although most industrial wastewater contains two or more toxic metals, there are few sorption studies on multicomponent metals by WPWS. This study has two goals: (i) conduct competitive adsorption using Cr, Cu and Zn as sorbates and examine their interaction in binary or ternary systems; and (ii) determine the effects of temperature on the kinetic sorption reaction. The sludge tested contained a high amount of organic matter (38%) and had a high cation exchange capacity (CEC, 255 cmol{sub c} kg{sup -1}). Infrared analysis reveals that carboxyl is the main functional group in this WPWS. The {sup 13}C NMR determination indicates alkyl-C and carboxyl-C are major organic functional groups. At steady state, there are about 40.4% (Cr), 35.0% (Cu) and 21.9% (Zn) sorbed in the initial 6.12 mM of single-component solutions. Only pseudo-second-order sorption kinetic model successfully describes the kinetics of sorption for all experimental metals. The rate constants, k{sub 2}, of Cr, Cu and Zn in single-component solutions are 0.016, 0.030 and 0.154 g mg{sup -1} min{sup -1}, respectively. The sorption of metals by WPWS in this competitive system shows the trend: Cr > Cu > Zn. Ions of charge, hydrated radius and electronic configuration are main factors affecting sorption capacity. The least sorption for Zn in this competitive system can be attributed to its full orbital and largest hydrated radius. Though the effect of temperature on Zn sorption is insignificant, high temperature favors the other metallic sorptions, in particular for Cr. However, the Cr sorption is lower than Cu at 10 deg. C. The Cr sorption by WPWS can be higher than that of Cu at 30 deg. and 50 deg. C.

  16. Multicomponent Aqueous Synthesis of Iodo-1,2,3-triazoles: Single-Step Models for Dual Modification of Free Peptide and Radioactive Iodo Labeling.

    Science.gov (United States)

    Li, Lingjun; Ding, Shengqiang; Yang, Yanping; Zhu, Anlian; Fan, Xincui; Cui, Mengchao; Chen, Changpo; Zhang, Guisheng

    2017-01-23

    Iodo-1,2,3-triazoles are of considerable interest for chemical and biomedical applications. However, current synthetic methods for preparing iodo-1,2,3-triazoles cannot easily be applied to the direct modification of bioactive molecules in water. Through the combination of water-compatible oxidative iodination and the copper-catalyzed alkyne-azide cycloaddition reaction, a novel copper-catalyzed aqueous multicomponent synthetic method for the preparation of 5-iodo-1,2,3-triazoles has been developed. The method is highly effective and selective for substrates including biologically relevant compounds with nucleoside, sugar, and amino acid moieties. Based on this aqueous tandem reaction, a direct single-step multicomponent dual modification of peptide is developed from readily available starting materials. Furthermore, the method could also be applied to concise and fast multicomponent radioactive 125 I labeling from an aqueous solution of commercially available sodium 125 iodide as a starting material. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Enhanced infrared transmittance properties in ultrafine MgAl2O4 nanoparticles synthesised by a single step combustion method, followed by hybrid microwave sintering

    Science.gov (United States)

    Mathew, C. T.; Vidya, S.; Koshy, Jacob; Solomon, Sam; Thomas, Jijimon K.

    2015-09-01

    Infrared transparent ceramics found to have potential applications as infrared windows and domes in strategic defence and space missions. Synthesis of ultrafine nanostructured MgAl2O4 ceramics by a modified single step auto-igniting combustion technique, followed by sintering of the sample by resistive and resistive-microwave hybrid heating to high density and their excellent infrared transmission characteristics are presented in this paper. Structural characterisations of MgAl2O4 nanoparticles reveal that the as prepared powder is phase pure, with average crystallite size ∼15 nm and possess a cubic structure. Optical band gap calculated using the Kubelka-Munk method is 5.75 eV. The thermal stability of the nanopowder at elevated temperatures has been studied using thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). Hybrid heating yield a substantial reduction in sintering temperature and soaking time relative to the conventional resistive heating, and the samples achieved >99% density by microwave-resistive hybrid heating. Scanning electron micrograph (SEM) showed that the pellets are well sintered. The pellet sintered by hybrid heating showed a better transmittance of ∼79% in the UV-Visible region and ∼82% in the mid IR region compared to pellet sintered by resistive heating which has ∼68% in the UV-Visible region and ∼66% in the mid IR region. The results confirm the effective use of nanocrystalline powders from modified combustion synthesis as starting material for the development of high quality IR transparent windows and domes. In addition the microwave hybrid sintering technique employed in the present study also contributes to the results of better transmittance characteristics in highly densified MgAl2O4 ceramic pellets.

  18. Quantitative analysis of multi-components by single marker—a rational method for the internal quality of Chinese herbal medicine

    Directory of Open Access Journals (Sweden)

    Chunsheng Zhu

    2017-03-01

    Full Text Available In order to achieve the comprehensive quality control of Chinese herbal medicine (CHM, the conventional practice of selecting a single marker for testing has been gradually replaced by the determination of multiple active components based on the characteristics of the synergistic interaction of CHM and applicability of sophisticated analytical techniques. However, with a huge number of CHM in the market and more complex preparations, the limited availability of various standard substances for quantitative analysis has been a major bottleneck in realizing the goal. To overcome these uprising problems, quantitative analysis of multi-components by single marker (QAMS was proposed and accepted as a new method to reflect the internal quality of CHM. In this review, the current knowledge about QAMS is systematically summarized, including the general content of QAMS, current status, and general procedure. Additionally, speculation is proposed about the future applications of QAMS approaches in the modernization and standardization of CHM.

  19. Multi-component analysis in sun-dried and sulfur-fumigated Angelicae Sinensis Radix by single marker quantitation and chemometric discrimination.

    Science.gov (United States)

    Lou, Yajing; Cai, Hao; Liu, Xiao; Cao, Gang; Tu, Sicong; Li, Songlin; Ma, Xiaoqing; Qin, Kunming; Cai, Baochang

    2014-01-01

    A new method has been developed for the simultaneous determination of ferulic acid, senkyunolide A, and Z-ligustilide in Angelicae Sinensis Radix before and after sulfur-fumigation using quantitative analysis of multi-components by a single marker (QAMS). The feasibility and accuracy of QAMS were checked by the external standard method, and various high-performance liquid chromatographic instruments and chromatographic conditions were investigated to verify its applicability. Using ferulic acid as the internal reference substance, and the contents of senkyunolide A and Z-ligustilide were calculated according to relative correction factors by high-performance liquid chromatography. Meanwhile, the influence of sulfur-fumigation on these chemical components in Angelicae Sinensis Radix were evaluated and discriminated by chromatographic fingerprint and chemometrics. There was no significant difference observed between the QAMS method and the external standard method. Furthermore, sulfur-fumigation reduced the contents of ferulic acid, senkyunolide A, and Z-ligustilide in Angelicae Sinensis Radix by some degree, and the sun-drying and sulfur-fumigation processing could be easily discriminated by chromatographic fingerprint and chemometrics. QAMS is a convenient and accurate approach to analyzing multi-component when reference substances are unavailable, simultaneously, chemometrics is an effective way to discriminate sun-dried and sulfur-fumigated Angelicae Sinensis Radix.

  20. Multicomponent MR Image Denoising

    Directory of Open Access Journals (Sweden)

    José V. Manjón

    2009-01-01

    Full Text Available Magnetic Resonance images are normally corrupted by random noise from the measurement process complicating the automatic feature extraction and analysis of clinical data. It is because of this reason that denoising methods have been traditionally applied to improve MR image quality. Many of these methods use the information of a single image without taking into consideration the intrinsic multicomponent nature of MR images. In this paper we propose a new filter to reduce random noise in multicomponent MR images by spatially averaging similar pixels using information from all available image components to perform the denoising process. The proposed algorithm also uses a local Principal Component Analysis decomposition as a postprocessing step to remove more noise by using information not only in the spatial domain but also in the intercomponent domain dealing in a higher noise reduction without significantly affecting the original image resolution. The proposed method has been compared with similar state-of-art methods over synthetic and real clinical multicomponent MR images showing an improved performance in all cases analyzed.

  1. Ultrafine cementitious grout

    Science.gov (United States)

    Ahrens, Ernst H.

    1999-01-01

    An ultrafine cementitious grout in three particle grades containing Portland cement, pumice as a pozzolanic material and superplasticizer in the amounts of about 30 wt. % to about 70 wt. % Portland cement; from about 30 wt. % to about 70 wt. % pumice containing at least 70% amorphous silicon dioxide; and from 1.2 wt. % to about 5.0 wt. % superplasticizer. The superplasticizer is dispersed in the mixing water prior to the addition of dry grout and the W/CM ratio is about 0.4 to 1/1. The grout has very high strength and very low permeability with good workability. The ultrafine particle sizes allow for sealing of microfractures below 10 .mu.m in width.

  2. [Quantitative analysis of seven phenolic acids in eight Yinqiao Jiedu serial preparations by quantitative analysis of multi-components with single-marker].

    Science.gov (United States)

    Wang, Jun-jun; Zhang, Li; Guo, Qing; Kou, Jun-ping; Yu, Bo-yang; Gu, Dan-hua

    2015-04-01

    The study aims to develop a unified method to determine seven phenolic acids (neochlorogenic acid, chlorogenic acid, 4-caffeoylquinic acid, caffeic acid, isochlorogenic acid B, isochlorogenic acid A and isochlorogenic acid C) contained in honeysuckle flower that is the monarch drug of all the eight Yinqiao Jiedu serial preparations using quantitative analysis of multi-components by single-marker (QAMS). Firstly, chlorogenic acid was used as a reference to get the average relative correction factors (RCFs) of the other phenolic acids in ratios to the reference; columns and instruments from different companies were used to validate the durability of the achieved RCFs in different levels of standard solutions; and honeysuckle flower extract was used as the reference substance to fix the positions of chromatographic peaks. Secondly, the contents of seven phenolic acids in eight different Yinqiao Jiedu serial preparations samples were calculated based on the RCFs durability. Finally, the quantitative results were compared between QAMS and the external standard (ES) method. The results have showed that the durability of the achieved RCFs is good (RSD during 0.80% - 2.56%), and there are no differences between the quantitative results of QAMS and ES (the relative average deviation quantitative control of honeysuckle flower principally prescribed in Yinqiao Jiedu serial preparations.

  3. A systematic study on the influencing parameters and improvement of quantitative analysis of multi-component with single marker method using notoginseng as research subject.

    Science.gov (United States)

    Wang, Chao-Qun; Jia, Xiu-Hong; Zhu, Shu; Komatsu, Katsuko; Wang, Xuan; Cai, Shao-Qing

    2015-03-01

    A new quantitative analysis of multi-component with single marker (QAMS) method for 11 saponins (ginsenosides Rg1, Rb1, Rg2, Rh1, Rf, Re and Rd; notoginsenosides R1, R4, Fa and K) in notoginseng was established, when 6 of these saponins were individually used as internal referring substances to investigate the influences of chemical structure, concentrations of quantitative components, and purities of the standard substances on the accuracy of the QAMS method. The results showed that the concentration of the analyte in sample solution was the major influencing parameter, whereas the other parameters had minimal influence on the accuracy of the QAMS method. A new method for calculating the relative correction factors by linear regression was established (linear regression method), which demonstrated to decrease standard method differences of the QAMS method from 1.20%±0.02% - 23.29%±3.23% to 0.10%±0.09% - 8.84%±2.85% in comparison with the previous method. And the differences between external standard method and the QAMS method using relative correction factors calculated by linear regression method were below 5% in the quantitative determination of Rg1, Re, R1, Rd and Fa in 24 notoginseng samples and Rb1 in 21 notoginseng samples. And the differences were mostly below 10% in the quantitative determination of Rf, Rg2, R4 and N-K (the differences of these 4 constituents bigger because their contents lower) in all the 24 notoginseng samples. The results indicated that the contents assayed by the new QAMS method could be considered as accurate as those assayed by external standard method. In addition, a method for determining applicable concentration ranges of the quantitative components assayed by QAMS method was established for the first time, which could ensure its high accuracy and could be applied to QAMS methods of other TCMs. The present study demonstrated the practicability of the application of the QAMS method for the quantitative analysis of multi-component

  4. Biosorption Behavior of Basic Red 46 and Violet 3 by Dead Pleurotus mutilus from Single- and Multicomponent Systems

    OpenAIRE

    Yeddou Mezenner, N.; Hamadi, A.; Kaddour, S.; Bensaadi, Z.; Bensmaili, A.

    2013-01-01

    The performance of nonviable P. mutilus for removal of Crystal Violet (CV) and Basic Red 46 (BR46) was investigated in single and binary systems. Batch kinetic studies were carried out as a function of pH, temperature, biomass amount, and dye concentration to determine the decolorization efficiency of biosorbent. In single system, the biosorption capacities of P. M. reached 166 and 76.92 mg/g for CV and BR46, respectively. A comparison of kinetic models applied to the adsorption of basic dyes...

  5. Biosorption Behavior of Basic Red 46 and Violet 3 by Dead Pleurotus mutilus from Single- and Multicomponent Systems

    Directory of Open Access Journals (Sweden)

    N. Yeddou Mezenner

    2013-01-01

    Full Text Available The performance of nonviable P. mutilus for removal of Crystal Violet (CV and Basic Red 46 (BR46 was investigated in single and binary systems. Batch kinetic studies were carried out as a function of pH, temperature, biomass amount, and dye concentration to determine the decolorization efficiency of biosorbent. In single system, the biosorption capacities of P. M. reached 166 and 76.92 mg/g for CV and BR46, respectively. A comparison of kinetic models applied to the adsorption of basic dyes onto P. Mutilus was evaluated for the pseudo-second-order and intraparticle diffusion kinetics models. The experimental data fitted very well the pseudo-second-order kinetic model, whereas diffusion is not only the rate-controlling step. The thermodynamic study indicates that the adsorption of dyes is spontaneous and endothermic process. In binary system, the biosorption capacities of P. Mutilus for both dyes decreased significantly compared to that in single system. Competitive coefficients calculated on a concentration basis using Sheindorf-Rebhun-Sheintuch (SRS equation were useful for describing the degree of competitive interaction in P. M.

  6. Multicomponent polymeric materials

    CERN Document Server

    Thomas, Sabu; Saha, Prosenjit

    2016-01-01

    The book offers an in-depth review of the materials design and manufacturing processes employed in the development of multi-component or multiphase polymer material systems. This field has seen rapid growth in both academic and industrial research, as multiphase materials are increasingly replacing traditional single-component materials in commercial applications. Many obstacles can be overcome by processing and using multiphase materials in automobile, construction, aerospace, food processing, and other chemical industry applications. The comprehensive description of the processing, characterization, and application of multiphase materials presented in this book offers a world of new ideas and potential technological advantages for academics, researchers, students, and industrial manufacturers from diverse fields including rubber engineering, polymer chemistry, materials processing and chemical science. From the commercial point of view it will be of great value to those involved in processing, optimizing an...

  7. Modeling multi-component transport and enhanced anaerobic dechlorination processes in a single fracture-clay matrix system

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Broholm, Mette Martina; Binning, Philip John

    2010-01-01

    Clayey tills contaminated with chlorinated solvents are a threat to groundwater and are difficult to remediate. A numerical model is developed for assessing leaching processes and for simulating the remediation via enhanced anaerobic dechlorination. The model simulates the transport...... of a contaminant in a single fracture-clay matrix system coupled with a reactive model for anaerobic dechlorination. The model takes into account microbially driven anaerobic dechlorination, where sequential Monod kinetics with competitive inhibition is used to model the reaction rates, and degradation...... to the physical processes, mainly diffusion in the matrix, than to the biogeochemical processes, when dechlorination is assumed to take place in a limited reaction zone only. The inclusion of sequential dechlorination in clay fracture transport models is crucial, as the contaminant flux to the aquifer...

  8. Single and multi-component adsorption of salicylic acid, clofibric acid, carbamazepine and caffeine from water onto transition metal modified and partially calcined inorganic-organic pillared clay fixed beds.

    Science.gov (United States)

    Cabrera-Lafaurie, Wilman A; Román, Félix R; Hernández-Maldonado, Arturo J

    2015-01-23

    Fixed-beds of transition metal (Co(2+), Ni(2+) or Cu(2+)) inorganic-organic pillared clays (IOCs) were prepared to study single- and multi-component non-equilibrium adsorption of a set of pharmaceutical and personal care products (PPCPs: salicylic acid, clofibric acid, carbamazepine and caffeine) from water. Adsorption capacities for single components revealed that the copper(II) IOCs have better affinity toward salicylic and clofibric acid. However, multi-component adsorption tests showed a considerable decrease in adsorption capacity for the acids and an unusual selectivity toward carbamazepine depending on the transition metal. This was attributed to a combination of competition between PPCPs for adsorption sites, adsorbate-adsorbate interactions, and plausible pore blocking caused by carbamazepine. The cobalt(II) IOC bed that was partially calcined to fractionate the surfactant moiety showcased the best selectivity toward caffeine, even during multi-component adsorption. This was due to a combination of a mildly hydrophobic surface and interaction between the PPCP and cobalt(II). In general, the tests suggest that these IOCs may be a potential solution for the removal of PPCPs if employed in a layered-bed configuration, to take care of families of adsorbates in a sequence that would produce sharpened concentration wavefronts. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Ultrafine particles in cities.

    Science.gov (United States)

    Kumar, Prashant; Morawska, Lidia; Birmili, Wolfram; Paasonen, Pauli; Hu, Min; Kulmala, Markku; Harrison, Roy M; Norford, Leslie; Britter, Rex

    2014-05-01

    Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Chemical aging of single and multicomponent biomass burning aerosol surrogate particles by OH: implications for cloud condensation nucleus activity

    Directory of Open Access Journals (Sweden)

    J. H. Slade

    2015-09-01

    Full Text Available Multiphase OH and O3 oxidation reactions with atmospheric organic aerosol (OA can influence particle physicochemical properties including composition, morphology, and lifetime. Chemical aging of initially insoluble or low-soluble single-component OA by OH and O3 can increase their water solubility and hygroscopicity, making them more active as cloud condensation nuclei (CCN and susceptible to wet deposition. However, an outstanding problem is whether the effects of chemical aging on their CCN activity are preserved when mixed with other organic or inorganic compounds exhibiting greater water solubility. In this work, the CCN activity of laboratory-generated biomass burning aerosol (BBA surrogate particles exposed to OH and O3 is evaluated by determining the hygroscopicity parameter, κ, as a function of particle type, mixing state, and OH and O3 exposure applying a CCN counter (CCNc coupled to an aerosol flow reactor (AFR. Levoglucosan (LEV, 4-methyl-5-nitrocatechol (MNC, and potassium sulfate (KS serve as representative BBA compounds that exhibit different hygroscopicity, water solubility, chemical functionalities, and reactivity with OH radicals, and thus exemplify the complexity of mixed inorganic/organic aerosol in the atmosphere. The CCN activities of all of the particles were unaffected by O3 exposure. Following exposure to OH, κ of MNC was enhanced by an order of magnitude, from 0.009 to ~ 0.1, indicating that chemically aged MNC particles are better CCN and more prone to wet deposition than pure MNC particles. No significant enhancement in κ was observed for pure LEV particles following OH exposure. κ of the internally mixed particles was not affected by OH oxidation. Furthermore, the CCN activity of OH-exposed MNC-coated KS particles is similar to the OH unexposed atomized 1 : 1 by mass MNC : KS binary-component particles. Our results strongly suggest that when OA is dominated by water-soluble organic carbon (WSOC or inorganic ions

  11. Multicomponent Syntheses of Macrocycles

    Science.gov (United States)

    Masson, Géraldine; Neuville, Luc; Bughin, Carine; Fayol, Aude; Zhu, Jieping

    How to access efficiently the macrocyclic structure remained to be a challenging synthetic topic. Although many elegant approaches/reactions have been developed, construction of diverse collection of macrocycles is still elusive. This chapter summarized the recently emerged research area dealing with multicomponent synthesis of macrocycles, with particular emphasis on the approach named "multiple multicomponent reaction using two bifunctional building blocks".

  12. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems

    Energy Technology Data Exchange (ETDEWEB)

    Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.

    1992-09-01

    The COMMIX-LAR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-lA to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a keg model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The internal aspects of the COMMIX-LAR/P program are presented, covering descriptions of subprograms, variables, and files.

  13. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems

    International Nuclear Information System (INIS)

    Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.

    1992-09-01

    The COMMIX-1AR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-1A to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a k-var-epsilon model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The input preparation and execution procedures are presented for the COMMIX-1AR/P program and several postprocessor programs which produce graphical displays of the calculated results

  14. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems

    Energy Technology Data Exchange (ETDEWEB)

    Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.

    1992-09-01

    The COMMIX-1AR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-1A to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a k-[var epsilon] model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The input preparation and execution procedures are presented for the COMMIX-1AR/P program and several postprocessor programs which produce graphical displays of the calculated results.

  15. Ultrafine particles in the atmosphere

    CERN Document Server

    Brown, L M; Harrison, R M; Maynard, A D; Maynard, R L

    2003-01-01

    Following the recognition that airborne particulate matter, even at quite modest concentrations, has an adverse effect on human health, there has been an intense research effort to understand the mechanisms and quantify the effects. One feature that has shone through is the important role of ultrafine particles as a contributor to the adverse effects of airborne particles. In this volume, many of the most distinguished researchers in the field provide a state-of-the-art overview of the scientific and medical research on ultrafine particles. Contents: Measurements of Number, Mass and Size Distr

  16. Multicomponent liquid ion exchange with chabazite zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, S.M.; Arnold, W.D. Jr.; Byers, C.W.

    1993-10-01

    In spite of the increasing commercial use of zeolites for binary and multicomponent sorption, the understanding of the basic mass-transfer processes associated with multicomponent zeolite ion-exchange systems is quite limited. This study was undertaken to evaluate Na-Ca-Mg-Cs-Sr ion exchange from an aqueous solution using a chabazite zeolite. Mass-transfer coefficients and equilibrium equations were determined from experimental batch-reactor data for single and multicomponent systems. The Langmuir isotherm was used to represent the equilibrium relationship for binary systems, and a modified Dubinin-Polyani model was used for the multicomponent systems. The experimental data indicate that diffusion through the microporous zeolite crystals is the primary diffusional resistance. Macropore diffusion also significantly contributes to the mass-transfer resistance. Various mass-transfer models were compared to the experimental data to determine mass-transfer coefficients. Effective diffusivities were obtained which accurately predicted experimental data using a variety of models. Only the model which accounts for micropore and macropore diffusion occurring in series accurately predicted multicomponent data using single-component diffusivities. Liquid and surface diffusion both contribute to macropore diffusion. Surface and micropore diffusivities were determined to be concentration dependent.

  17. Microwave multicomponent synthesis.

    Science.gov (United States)

    Hügel, Helmut M

    2009-12-01

    In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS) that have been achieved over the last five years.

  18. Microwave Multicomponent Synthesis

    Directory of Open Access Journals (Sweden)

    Helmut M. Hügel

    2009-12-01

    Full Text Available In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS that have been achieved over the last five years.

  19. Microwave Multicomponent Synthesis

    OpenAIRE

    Helmut M. Hügel

    2009-01-01

    In the manner that very important research is often performed by multidisciplinary research teams, the applications of multicomponent reactions involving the combination of multiple starting materials with different functional groups leading to the higher efficiency and environmentally friendly construction of multifunctional/complex target molecules is growing in importance. This review will explore the advances and advantages in microwave multicomponent synthesis (MMS) that have been achiev...

  20. Nanomaterials vs Ambient Ultrafine Particles

    DEFF Research Database (Denmark)

    Stone, Vicki; Miller, Mark R.; Clift, Martin J. D.

    2017-01-01

    BACKGROUND: A rich body of literature exists that has demonstrated adverse human health effects following exposure to ambient air particulate matter (PM), and there is strong support for an important role of ultrafine (nanosized) particles. At present, relatively few human health or epidemiology ...

  1. Detection of Ultrafine Anaphase Bridges

    DEFF Research Database (Denmark)

    Bizard, Anna H; Nielsen, Christian F; Hickson, Ian D

    2018-01-01

    Ultrafine anaphase bridges (UFBs) are thin DNA threads linking the separating sister chromatids in the anaphase of mitosis. UFBs are thought to form when topological DNA entanglements between two chromatids are not resolved prior to anaphase onset. In contrast to other markers of defective...

  2. Protective effects of pulmonary epithelial lining fluid on oxidative stress and DNA single-strand breaks caused by ultrafine carbon black, ferrous sulphate and organic extract of diesel exhaust particles

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Hsiao-Chi [School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan (China); Cheng, Yi-Ling; Lei, Yu-Chen [Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Chang, Hui-Hsien [Institute of Environmental Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Cheng, Tsun-Jen, E-mail: tcheng@ntu.edu.tw [Institute of Occupational Medicine and Industrial Hygiene, College of Public Health, National Taiwan University, Taipei, Taiwan (China); Department of Public Health, College of Public Health, National Taiwan University, Taipei, Taiwan (China)

    2013-02-01

    Pulmonary epithelial lining fluid (ELF) is the first substance to make contact with inhaled particulate matter (PM) and interacts chemically with PM components. The objective of this study was to determine the role of ELF in oxidative stress, DNA damage and the production of proinflammatory cytokines following physicochemical exposure to PM. Ultrafine carbon black (ufCB, 15 nm; a model carbonaceous core), ferrous sulphate (FeSO{sub 4}; a model transition metal) and a diesel exhaust particle (DEP) extract (a model organic compound) were used to examine the acellular oxidative potential of synthetic ELF and non-ELF systems. We compared the effects of exposure to ufCB, FeSO{sub 4} and DEP extract on human alveolar epithelial Type II (A549) cells to determine the levels of oxidative stress, DNA single-strand breaks and interleukin-8 (IL-8) production in ELF and non-ELF systems. The effects of ufCB and FeSO{sub 4} on the acellular oxidative potential, cellular oxidative stress and DNA single-strand breakage were mitigated significantly by the addition of ELF, whereas there was no decrease following treatment with the DEP extract. There was no significant effect on IL-8 production following exposure to samples that were suspended in ELF/non-ELF systems. The results of the present study indicate that ELF plays an important role in the initial defence against PM in the pulmonary environment. Experimental components, such as ufCB and FeSO{sub 4}, induced the production of oxidative stress and led to DNA single-strand breaks, which were moderately prevented by the addition of ELF. These findings suggest that ELF plays a protective role against PM-driven oxidative stress and DNA damage. -- Highlights: ► To determine the role of ELF in ROS, DNA damage and IL-8 after exposure to PM. ► ufCB, FeSO{sub 4} and DEP extract were used to examine the protective effects of ELF. ► PM-driven oxidative stress and DNA single-strand breakage were mitigated by ELF. ► The findings

  3. Strategies for Innovation in Multicomponent Reaction Design

    OpenAIRE

    Ganem, Bruce

    2009-01-01

    By generating structural complexity in a single step from three or more reactants, multicomponent reactions (MCRs) make it possible to synthesize target compounds with greater efficiency and atom economy. The history of such reactions can be traced to the mid-nineteenth century when Strecker first produced α-aminonitriles from the condensation of aldehydes with ammonia and hydrogen cyanide.

  4. Surgical smoke and ultrafine particles

    Directory of Open Access Journals (Sweden)

    Nowak Dennis

    2008-12-01

    Full Text Available Abstract Background Electrocautery, laser tissue ablation, and ultrasonic scalpel tissue dissection all generate a 'surgical smoke' containing ultrafine ( Methods To measure the amount of generated particulates in 'surgical smoke' during different surgical procedures and to quantify the particle number concentration for operation room personnel a condensation particle counter (CPC, model 3007, TSI Inc. was applied. Results Electro-cauterization and argon plasma tissue coagulation induced the production of very high number concentration (> 100000 cm-3 of particles in the diameter range of 10 nm to 1 μm. The peak concentration was confined to the immediate local surrounding of the production side. In the presence of a very efficient air conditioning system the increment and decrement of ultrafine particle occurrence was a matter of seconds, with accumulation of lower particle number concentrations in the operation room for only a few minutes. Conclusion Our investigation showed a short term very high exposure to ultrafine particles for surgeons and close assisting operating personnel – alternating with longer periods of low exposure.

  5. Unraveling the atomic structure of ultrafine iron clusters

    KAUST Repository

    Wang, Hongtao

    2012-12-18

    Unraveling the atomic structures of ultrafine iron clusters is critical to understanding their size-dependent catalytic effects and electronic properties. Here, we describe the stable close-packed structure of ultrafine Fe clusters for the first time, thanks to the superior properties of graphene, including the monolayer thickness, chemical inertness, mechanical strength, electrical and thermal conductivity. These clusters prefer to take regular planar shapes with morphology changes by local atomic shuffling, as suggested by the early hypothesis of solid-solid transformation. Our observations differ from observations from earlier experimental study and theoretical model, such as icosahedron, decahedron or cuboctahedron. No interaction was observed between Fe atoms or clusters and pristine graphene. However, preferential carving, as observed by other research groups, can be realized only when Fe clusters are embedded in graphene. The techniques introduced here will be of use in investigations of other clusters or even single atoms or molecules.

  6. Ultrafine particle emissions from waterpipes.

    Science.gov (United States)

    Monn, Ch; Kindler, Ph; Meile, A; Brändli, O

    2007-12-01

    Ultrafine particle emissions from waterpipes and their impact on human health have not been extensively studied. The aim of this study was to characterise the inhalation pattern of waterpipe smokers, and (a) construct apparatus to simulate waterpipe smoking in the laboratory, and (b) characterise mainstream emissions from waterpipes under different smoking conditions. Real life waterpipe smoking patterns were first measured with a spirometer. The average smoking pattern was then mechanically simulated in apparatus. Total particle number concentrations were determined with a condensation particle counter (CPC) for particles between 0.02 microm and 1 microm (P-Trak UPC, Model 8525, TSI) and the particle size fraction was determined with a differential mobility analyser (DMA) for particles from 0.01 microm to 0.5 microm. This instrument was coupled with a laser particle spectrometer for particles between 0.35 microm and 10 microm (Wide Range Particle Spectrometer, Model 1000XP, MSC Corp). Carbon monoxide levels were determined with an electrochemical sensor (Q-Trak monitor, Model 8554, TSI). The tidal volume of an average waterpipe breath of 5 seconds was found to be 1 (SD 0.47) litre. The intervals between breaths on average were 25.5 (SD 10.2) seconds. Particle number concentrations of ultrafine particles in mainstream smoke during waterpipe smoking ranged up to 70 x 10(9) particles per litre. The median diameter of the particles in a full smoking set with charcoal, tobacco and water was 0.04 microm. Smoke from the heated tobacco contributed to particles in the size range between 0.01 microm and 0.2 microm. The glowing piece of charcoal only contributed to particles smaller than 0.05 microm. Waterpipe smoking emits large amounts of ultrafine particles. With regard to particle emissions, smoking waterpipes may carry similar health risks to smoking cigarettes.

  7. Crystallization In Multicomponent Glasses

    International Nuclear Information System (INIS)

    Kruger, A.A.; Hrma, P.R.

    2009-01-01

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  8. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    KRUGER AA; HRMA PR

    2009-10-08

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  9. [Design and analyze mathematical algorithms of intestinal absorption and metabolism of multicomponent drug].

    Science.gov (United States)

    Dong, Ling; Xiang, Jia-Mei; Wang, Yun; Wu, Rui-Guang; Tang, Ming-Min; Sun, Mo-Han

    2014-12-01

    Evaluation of the permeability mainly focuses on intestinal absorption in biopharmaceutics classification system (BCS). It is more complicated that the absorption and metabolism under multicomponent environment in biopharmaceutics classification system of Chinese materia medica (CMMBCS) compared with single component environment, which needs suitable mathematical models to be described. Therefore, with full consideration of existing single component mathematical algorithm combining with the characteristics of intestinal absorption and metabolism, we explored and designed a new mathematical algorithm of intestinal absorption and metabolism of multicomponent drug. Then we put forward a new coefficient, P (influence), the relative change rate of the single component's intestinal absorption and metabolism under multicomponent environment compared with single component environment, which described the influences of intestinal absorption and metabolism of the component under multicomponent environment. Moreover, P (influence) highlights the distinctive characteristics of multicomponent drug's intestinal absorption and metabolism, and lays the foundation for the construction of CMMBCS.

  10. ULTRAFINE FLUORESCENT DIAMONDS IN NANOTECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Kanyuk M. I.

    2014-07-01

    Full Text Available The purpose of the work is to summarize the literature data concerning ultrafine diamonds, namely their industrial production, as well as considerable photostability and biocompatibility that promote their use in modern visualization techniques. It is shown that due to the unique physical properties, they are promising materials for using in nanotechnology in the near future. Possibility of diverse surface modification, small size and large absorption surface are the basis for their use in different approaches for drug and gene delivery into a cell. The changes in the properties of nanodiamond surface modification methods of their creation, stabilization and applications are described. It can be said that fluorescent surface-modified nanodiamonds are a promising target in various research methods that would be widely used for labeling of living cells, as well as in the processes of genes and drugs delivery into a cell.

  11. Ultracentrifugation for ultrafine nanodiamond fractionation

    Science.gov (United States)

    Koniakhin, S. V.; Besedina, N. A.; Kirilenko, D. A.; Shvidchenko, A. V.; Eidelman, E. D.

    2018-01-01

    In this paper we propose a method for ultrafine fractionation of nanodiamonds using the differential centrifugation in the fields up to 215000g. The developed protocols yield 4-6 nm fraction giving main contribution to the light scattering intensity. The desired 4-6 nm fraction can be obtained from various types of initial nanodiamonds: three types of detonation nanodiamonds differing in purifying methods, laser synthesis nanodiamonds and nanodiamonds made by milling. The characterization of the obtained hydrosols was conducted with Dynamic Light Scattering, Zeta potential measurements, powder XRD and TEM. According to powder XRD and TEM data ultracentrifugation also leads to a further fractionation of the primary diamond nanocrystallites in the hydrosols from 4 to 2 nm.

  12. Volatility and mixing states of ultrafine particles from biomass burning

    International Nuclear Information System (INIS)

    Maruf Hossain, A.M.M.; Park, Seungho; Kim, Jae-Seok; Park, Kihong

    2012-01-01

    Highlights: ► Size distribution, volatility, and mixing states of ultrafine particles emitted from rice straw, oak, and pine burning under different burning conditions were investigated. ► Smoldering combustion emitted larger mode particles in higher numbers than smaller mode particles, while the converse was true for flaming combustion. ► While the flaming combustion and open burning results imply there is internal mixing of OC and BC, smoldering combustion in rice straw produced ultrafine particles devoid of BC. ► Mixing state of ultrafine particles from biomass burning can alter the single scattering albedo, and might even change the sign of radiative forcing. - Abstract: Fine and ultrafine carbonaceous aerosols produced from burning biomasses hold enormous importance in terms of assessing radiation balance and public health hazards. As such, volatility and mixing states of size-selected ultrafine particles (UFP) emitted from rice straw, oak, and pine burning were investigated by using volatility tandem differential mobility analyzer (VTDMA) technique in this study. Rice straw combustion produced unimodal size distributions of emitted aerosols, while bimodal size distributions from combustions of oak (hardwood) and pine (softwood) were obtained. A nearness of flue gas temperatures and a lower CO ratio of flaming combustion (FC) to smoldering combustion (SC) were characteristic differences found between softwood and hardwood. SC emitted larger mode particles in higher numbers than smaller mode particles, while the converse was true for FC. Rice straw open burning UFPs exhibited a volatilization behavior similar to that between FC and SC. In addition, internal mixing states were observed for size-selected UFPs in all biomasses for all combustion conditions, while external mixing states were only observed for rice straw combustion. Results for FC and open burning suggested there was an internal mixing of volatile organic carbon (OC) and non-volatile core (e

  13. Multicomponent diffusion in two-temperature magnetohydrodynamics

    International Nuclear Information System (INIS)

    Ramshaw, J.D.; Chang, C.H.

    1996-01-01

    A recent hydrodynamic theory of multicomponent diffusion in multitemperature gas mixtures [J. D. Ramshaw, J. Non-Equilib. Thermodyn. 18, 121 (1993)] is generalized to include the velocity-dependent Lorentz force on charged species in a magnetic field B. This generalization is used to extend a previous treatment of ambipolar diffusion in two-temperature multicomponent plasmas [J. D. Ramshaw and C. H. Chang, Plasma Chem. Plasma Process. 13, 489 (1993)] to situations in which B and the electrical current density are nonzero. General expressions are thereby derived for the species diffusion fluxes, including thermal diffusion, in both single- and two-temperature multicomponent magnetohydrodynamics (MHD). It is shown that the usual zero-field form of the Stefan-Maxwell equations can be preserved in the presence of B by introducing generalized binary diffusion tensors dependent on B. A self-consistent effective binary diffusion approximation is presented that provides explicit approximate expressions for the diffusion fluxes. Simplifications due to the small electron mass are exploited to obtain an ideal MHD description in which the electron diffusion coefficients drop out, resistive effects vanish, and the electric field reduces to a particularly simple form. This description should be well suited for numerical calculations. copyright 1996 The American Physical Society

  14. Multicomponent ion exchange model

    International Nuclear Information System (INIS)

    Robinson, S.M.; Arnold, W.D.; Byers, C.H.

    1990-01-01

    The optimization of ion-exchange column design becomes increasingly important in applications where high efficiency is required to remove trace components in wastewater to very low discharge requirements and for treating hazardous wastewaters where the disposal costs for secondary waste is extremely high. A predictive mathematical model is being developed for improved design of ion-exchange columns for treatment of wastewaters which are contaminated with trace quantities of Sr-90 and Cs-137. Equilibria isotherms and mass transfer mechanisms are being experimentally determined for isothermal multicomponent ion exchange of Ca, Mg, Na, Ca, and Sr with Ionsive IE-95 chabazite zeolite. These equations are being included in a mathematical model to determine the cation breakthrough curves for different column configurations and operating conditions

  15. Inverse design of multicomponent assemblies

    Science.gov (United States)

    Piñeros, William D.; Lindquist, Beth A.; Jadrich, Ryan B.; Truskett, Thomas M.

    2018-03-01

    Inverse design can be a useful strategy for discovering interactions that drive particles to spontaneously self-assemble into a desired structure. Here, we extend an inverse design methodology—relative entropy optimization—to determine isotropic interactions that promote assembly of targeted multicomponent phases, and we apply this extension to design interactions for a variety of binary crystals ranging from compact triangular and square architectures to highly open structures with dodecagonal and octadecagonal motifs. We compare the resulting optimized (self- and cross) interactions for the binary assemblies to those obtained from optimization of analogous single-component systems. This comparison reveals that self-interactions act as a "primer" to position particles at approximately correct coordination shell distances, while cross interactions act as the "binder" that refines and locks the system into the desired configuration. For simpler binary targets, it is possible to successfully design self-assembling systems while restricting one of these interaction types to be a hard-core-like potential. However, optimization of both self- and cross interaction types appears necessary to design for assembly of more complex or open structures.

  16. Recent advances in isocyanide-based multicomponent chemistry

    NARCIS (Netherlands)

    Dömling, Alexander

    2002-01-01

    Multicomponent reactions (MCRs) provide a powerful tool towards the one-pot synthesis of diverse and complex compounds on the one hand and small and 'drug-like' heterocycles on the other hand. No other single synthesis technology enables chemists to search such large chemical spaces as provided by

  17. Micro-/nanostructured multicomponent molecular materials: design, assembly, and functionality.

    Science.gov (United States)

    Yan, Dongpeng

    2015-03-23

    Molecule-based micro-/nanomaterials have attracted considerable attention because their properties can vary greatly from the corresponding macro-sized bulk systems. Recently, the construction of multicomponent molecular solids based on crystal engineering principles has emerged as a promising alternative way to develop micro-/nanomaterials. Unlike single-component materials, the resulting multicomponent systems offer the advantages of tunable composition, and adjustable molecular arrangement, and intermolecular interactions within their solid states. The study of these materials also supplies insight into how the crystal structure, molecular components, and micro-/nanoscale effects can influence the performance of molecular materials. In this review, we describe recent advances and current directions in the assembly and applications of crystalline multicomponent micro-/nanostructures. Firstly, the design strategies for multicomponent systems based on molecular recognition and crystal engineering principles are introduced. Attention is then focused on the methods of fabrication of low-dimensional multicomponent micro-/nanostructures. Their new applications are also outlined. Finally, we briefly discuss perspectives for the further development of these molecular crystalline micro-/nanomaterials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Rogue waves in the multicomponent Mel'nikov system and multicomponent Schrödinger–Boussinesq system

    Science.gov (United States)

    Sun, Baonan; Lian, Zhan

    2018-02-01

    By virtue of the bilinear method and the KP hierarchy reduction technique, exact explicit rational solutions of the multicomponent Mel'nikov equation and the multicomponent Schrödinger-Boussinesq equation are constructed, which contain multicomponent short waves and single-component long wave. For the multicomponent Mel'nikov equation, the fundamental rational solutions possess two different behaviours: lump and rogue wave. It is shown that the fundamental (simplest) rogue waves are line localised waves which arise from the constant background with a line profile and then disappear into the constant background again. The fundamental line rogue waves can be classified into three: bright, intermediate and dark line rogue waves. Two subclasses of non-fundamental rogue waves, i.e., multirogue waves and higher-order rogue waves are discussed. The multirogue waves describe interaction of several fundamental line rogue waves, in which interesting wave patterns appear in the intermediate time. Higher-order rogue waves exhibit dynamic behaviours that the wave structures start from lump and then retreat back to it. Moreover, by taking the parameter constraints further, general higher-order rogue wave solutions for the multicomponent Schrödinger-Boussinesq system are generated.

  19. Fatigue mechanisms in ultrafine-grained copper

    Czech Academy of Sciences Publication Activity Database

    Lukáš, Petr; Kunz, Ludvík; Svoboda, Milan

    2009-01-01

    Roč. 47, č. 1 (2009), s. 1-9 ISSN 0023-432X R&D Projects: GA AV ČR(CZ) 1QS200410502 Institutional research plan: CEZ:AV0Z20410507 Keywords : ultrafine-grained copper * effect of purity * effect of temperature Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.345, year: 2007

  20. Ultrafine particle characteristics in seven industrial plants.

    Science.gov (United States)

    Elihn, Karine; Berg, Peter

    2009-07-01

    Ultrafine particles are considered as a possible cause of some of the adverse health effects caused by airborne particles. In this study, the particle characteristics were measured in seven Swedish industrial plants, with a special focus on the ultrafine particle fraction. Number concentration, size distribution, surface area concentration, and mass concentration were measured at 10 different job activities, including fettling, laser cutting, welding, smelting, core making, moulding, concreting, grinding, sieving powders, and washing machine goods. A thorough particle characterization is necessary in workplaces since it is not clear yet which choice of ultrafine particle metric is the best to measure in relation to health effects. Job activities were given a different order of rank depending on what particle metric was measured. An especially high number concentration (130 x 10(3) cm(-3)) and percentage of ultrafine particles (96%) were found at fettling of aluminium, whereas the highest surface area concentration (up to 3800 mum(2) cm(-3)) as well as high PM10 (up to 1 mg m(-3)) and PM1 (up to 0.8 mg m(-3)) were found at welding and laser cutting of steel. The smallest geometric mean diameter (22 nm) was found at core making (geometric standard deviation: 1.9).

  1. Personal exposure to ultrafine particles.

    Science.gov (United States)

    Wallace, Lance; Ott, Wayne

    2011-01-01

    Personal exposure to ultrafine particles (UFP) can occur while people are cooking, driving, smoking, operating small appliances such as hair dryers, or eating out in restaurants. These exposures can often be higher than outdoor concentrations. For 3 years, portable monitors were employed in homes, cars, and restaurants. More than 300 measurement periods in several homes were documented, along with 25 h of driving two cars, and 22 visits to restaurants. Cooking on gas or electric stoves and electric toaster ovens was a major source of UFP, with peak personal exposures often exceeding 100,000 particles/cm³ and estimated emission rates in the neighborhood of 10¹² particles/min. Other common sources of high UFP exposures were cigarettes, a vented gas clothes dryer, an air popcorn popper, candles, an electric mixer, a toaster, a hair dryer, a curling iron, and a steam iron. Relatively low indoor UFP emissions were noted for a fireplace, several space heaters, and a laser printer. Driving resulted in moderate exposures averaging about 30,000 particles/cm³ in each of two cars driven on 17 trips on major highways on the East and West Coasts. Most of the restaurants visited maintained consistently high levels of 50,000-200,000 particles/cm³ for the entire length of the meal. The indoor/outdoor ratios of size-resolved UFP were much lower than for PM₂.₅ or PM₁₀, suggesting that outdoor UFP have difficulty in penetrating a home. This in turn implies that outdoor concentrations of UFP have only a moderate effect on personal exposures if indoor sources are present. A time-weighted scenario suggests that for typical suburban nonsmoker lifestyles, indoor sources provide about 47% and outdoor sources about 36% of total daily UFP exposure and in-vehicle exposures add the remainder (17%). However, the effect of one smoker in the home results in an overwhelming increase in the importance of indoor sources (77% of the total).

  2. Multi-Component Organic Layers on Metal Substrates.

    Science.gov (United States)

    Goiri, Elizabeth; Borghetti, Patrizia; El-Sayed, Afaf; Ortega, J Enrique; de Oteyza, Dimas G

    2016-02-17

    Increasingly high hopes are being placed on organic semiconductors for a variety of applications. Progress along these lines, however, requires the design and growth of increasingly complex systems with well-defined structural and electronic properties. These issues have been studied and reviewed extensively in single-component layers, but the focus is gradually shifting towards more complex and functional multi-component assemblies such as donor-acceptor networks. These blends show different properties from those of the corresponding single-component layers, and the understanding on how these properties depend on the different supramolecular environment of multi-component assemblies is crucial for the advancement of organic devices. Here, our understanding of two-dimensional multi-component layers on solid substrates is reviewed. Regarding the structure, the driving forces behind the self-assembly of these systems are described. Regarding the electronic properties, recent insights into how these are affected as the molecule's supramolecular environment changes are explained. Key information for the design and controlled growth of complex, functional multicomponent structures by self-assembly is summarized. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Multicomponent reactions in polymer synthesis.

    Science.gov (United States)

    Kakuchi, Ryohei

    2014-01-03

    More participants, yet efficient reactions: Multicomponent reactions (MCRs) have found application in polymer chemistry both in the synthesis of multifunctional monomers and in post-polymerization modification. Examples include the Passerini three-component reaction, the Ugi four-component reaction, and the copper-catalyzed MCR. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging-ion mass spectrometry

    NARCIS (Netherlands)

    Rafiee Fanood, M.M.; Ram, N.B.; Lehmann, C.S.; Powis, I.; Janssen, M.H.M.

    2015-01-01

    Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how

  5. A chemical analyzer for charged ultrafine particles

    OpenAIRE

    S. G. Gonser; A. Held

    2013-01-01

    New particle formation is a frequent phenomenon in the atmosphere and of major significance for the earth's climate and human health. To date the mechanisms leading to the nucleation of particles as well as to aerosol growth are not completely understood. A lack of appropriate measurement equipment for online analysis of the chemical composition of freshly nucleated particles is one major limitation. We have developed a Chemical Analyzer for Charged Ultrafine Particles (CAChUP) capable...

  6. A chemical analyzer for charged ultrafine particles

    OpenAIRE

    S. G. Gonser; A. Held

    2013-01-01

    New particle formation is a frequent phenomenon in the atmosphere and of major significance for the Earth's climate and human health. To date the mechanisms leading to the nucleation of particles as well as to aerosol growth are not completely understood. A lack of appropriate measurement equipment for online analysis of the chemical composition of freshly nucleated particles is one major limitation. We have developed a Chemical Analyzer for Charged Ultrafine Particles (CAChUP) capable of ana...

  7. [Ultrafine particle emissions from laser printers].

    Science.gov (United States)

    Grana, Mario; Vicentini, Laura; Pietroiusti, Antonio; Magrini, Andrea

    2015-01-01

    In recent years there has been growing attention to the importance of indoor air quality on which scientist and experts have no doubts since in modern society we tend to spend most of the time in various types of indoor environments (office, private homes, etc.). Laser printers, in particular, release an aerosol into the environment including solid and liquid particles and gaseous compounds. The measurement of all these components is not practically feasible. Therefore, it is necessary to identify a marker which, when measured, shows accurately the frequency, duration and magnitude of the exposure. The measure with an optical particle counter (OPC) and a condensation particle counter (CPC) is an indicator with high sensitivity and representativeness. The major advantage of using these tools is the ability to detect the presence of ultrafine particles and also detect the particles in the liquid phase. The continuous recording of submicron particulate matter emitted during the printing activity allows to measure the exposure of personnel, while the ratio between the peak values and the values without printing activity can be used to classify the printers according to their emissivity. The particulate generated during the processes of printing has size less than 0.3 micron and therefore extends in the size range of nanoparticles (ultrafine particles less than 100 nm). These activities lead to high concentrations of ultrafine particles with a variability related to factors such as type of printer, toner, paper type, frequency of maintenance and air exchange. The concentrations of ultrafine particles in office environments can be reduced by proper choice of the printers, with the use of appropriate filtration techniques and placing the equipment away from workstations.

  8. Potential Theory of Multicomponent Adsorption

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1998-01-01

    We developed a theory of multicomponent adsorption on the basis of the potential concept originally suggested by Polanyi. The mixture is considered as a heterogeneous substance segregated in the external field emitted by the adsorbent. The same standard equation of state, with no additional fitting...... parameters, is used for the segregated and for the bulk phases. With this approach, few parameters are needed to correlate pure component adsorption isotherms. These parameters may be used to predict adsorption equilibria of multicomponent mixtures without additional adjustment. A connection between...... the potential theory and the spreading pressure concept is established, and problems of the theory consistency are studied. Numerical algorithms are suggested for evaluation of the segregated state of the mixture in the potential field of adsorption forces. Comparison with experimental data shows good agreement...

  9. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems. Volume 2, User`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.

    1992-09-01

    The COMMIX-1AR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-1A to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a k-{var_epsilon} model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The input preparation and execution procedures are presented for the COMMIX-1AR/P program and several postprocessor programs which produce graphical displays of the calculated results.

  10. A Sustainable Multicomponent Pyrimidine Synthesis.

    Science.gov (United States)

    Deibl, Nicklas; Ament, Kevin; Kempe, Rhett

    2015-10-14

    Since alcohols are accessible from indigestible biomass (lignocellulose), the development of novel preferentially catalytic reactions in which alcohols are converted into important classes of fine chemicals is a central topic of sustainable synthesis. Multicomponent reactions are especially attractive in organic chemistry as they allow the synthesis of large libraries of diversely functionalized products in a short time when run in a combinatorial fashion. Herein, we report a novel, regioselective, iridium-catalyzed multicomponent synthesis of pyrimidines from amidines and up to three (different) alcohols. This reaction proceeds via a sequence of condensation and dehydrogenation steps which give rise to selective C-C and C-N bond formations. While the condensation steps deoxygenate the alcohol components, the dehydrogenations lead to aromatization. Two equiv of hydrogen and water are liberated in the course of the reactions. PN5P-Ir-pincer complexes, recently developed in our laboratory, catalyze this sustainable multicomponent process most efficiently. A total of 38 different pyrimidines were synthesized in isolated yields of up to 93%. Strong points of the new protocol are its regioselectivity and thus the immediate access to pyrimidines that are highly and unsymmetrically decorated with alkyl or aryl substituents. The combination of this novel protocol with established methods for converting alcohols to nitriles now allows to selectively assemble pyrimidines from four alcohol building blocks and 2 equiv of ammonia.

  11. Preparation of ultrafine poly(sodium 4-styrenesulfonate) fibres via ...

    Indian Academy of Sciences (India)

    The ultrafine poly (sodium 4-styrenesulfonate) (NaPSS) fibres have been prepared for the first time by electrospinning. The spinning solutions (NaPSS aqueous solutions) in varied concentrations were studied for electrospinning into ultrafine fibres. The results indicated that the smooth fibre could be formed when the ...

  12. Preparation of ultrafine poly (sodium 4-styrenesulfonate) fibres via ...

    Indian Academy of Sciences (India)

    The ultrafine poly (sodium 4-styrenesulfonate) (NaPSS) fibres have been prepared for the first time by electrospinning. The spinning solutions (NaPSS aqueous solutions) in varied concentrations were studied for electrospinning into ultrafine fibres. The results indicated that the smooth fibre could be formed when the ...

  13. Ultrafine particle exposure in Danish residencies

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Karottki, Dorina Gabriela; Wierzbicka, Aneta

    2016-01-01

    We measured ultrafine particle concentrations in 56 Danish residences, estimated the daily integrated exposure of the occupants and apportioned this exposure to source events. The residential daily integrated particle number (PN) exposure in the homes was substantial and source events, especially...... candle burning, cooking, toasting and unknown activities, were responsible on average for ∼65% of the residential integrated exposure. Residents of another 60 homes were then asked to carry a backpack equipped with a GPS recorder and a portable monitor to measure real-time individual exposure over ~48 h...

  14. BUFFER CAPACITY IN HETEROGENEOUS MULTICOMPONENT SYSTEMS. REVIEW

    Directory of Open Access Journals (Sweden)

    Oxana Spinu

    2015-12-01

    Full Text Available The quantitative basis of the theory of buffer properties for two-phase acid-base buffer systems and for multicomponent heterogeneous systems has been derived. The analytical equations with respect to all components for diverse multicomponent systems were deduced. It has been established, that the buffer capacities of components are mutually proportional.

  15. Multicomponent diffusivities from the free volume theory

    NARCIS (Netherlands)

    Wesselingh, J.A; Bollen, A.M

    In this paper the free volume theory of diffusion is extended to multicomponent mixtures. The free volume is taken to be accessible for any component according to its surface. fraction. The resulting equations predict multicomponent (Maxwell-Stefan) diffusivities in simple liquid mixtures from pure

  16. Ultrafine particle emission of waste incinerators and comparison to the exposure of urban citizens.

    Science.gov (United States)

    Buonanno, Giorgio; Morawska, Lidia

    2015-03-01

    On the basis of the growing interest on the impact of airborne particles on human exposure as well as the strong debate in Western countries on the emissions of waste incinerators, this work reviewed existing literature to: (i) show the emission factors of ultrafine particles (particles with a diameter less than 100 nm) of waste incinerators; and (ii) assess the contribution of waste incinerators in terms of ultrafine particles to exposure and dose of people living in the surrounding areas of the plants in order to estimate eventual risks. The review identified only a limited number of studies measuring ultrafine particle emissions, and in general they report low particle number concentrations at the stack (the median value was equal to 5.5×10(3) part cm(-3)), in most cases higher than the outdoor background value. The lowest emissions were achieved by utilization of the bag-house filter which has an overall number-based filtration efficiency higher than 99%. Referring to reference case, the corresponding emission factor is equal to 9.1×10(12) part min(-1), that is lower than one single high-duty vehicle. Since the higher particle number concentrations found in the most contributing microenvironments to the exposure (indoor home, transportation, urban outdoor), the contribution of the waste incinerators to the daily dose can be considered as negligible. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Removal of ultrafine particles from indoor environment

    DEFF Research Database (Denmark)

    Ardkapan, Siamak Rahimi

    In Denmark, people spend most of their time indoors. Therefore, indoor air quality is an important public health issue as people are exposed to pollutants indoors. Pollutants including gases and particles come from outdoors to the inside of a building. They may also be generated indoors by cooking......, candle burning, emission from building material, etc. Particles are divided into coarse, fine and ultrafine particles (UFP) depending on their size. Research has indicated that UFPs with diameters less than 100 nanometer (nm) may be harmful to the human body. Increased ventilation is commonly discussed...... by researchers as a solution for reducing the particle concentration in the indoor air. Recirculation of air through portable air cleaners has also been discussed. The scope of this study is to investigate possibilities, applications and limitations of using recirculated air in combination with new air cleaning...

  18. Substantial convection and precipitation enhancements by ultrafine aerosol particles

    Science.gov (United States)

    Fan, Jiwen; Rosenfeld, Daniel; Zhang, Yuwei; Giangrande, Scott E.; Li, Zhanqing; Machado, Luiz A. T.; Martin, Scot T.; Yang, Yan; Wang, Jian; Artaxo, Paulo; Barbosa, Henrique M. J.; Braga, Ramon C.; Comstock, Jennifer M.; Feng, Zhe; Gao, Wenhua; Gomes, Helber B.; Mei, Fan; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; de Souza, Rodrigo A. F.

    2018-01-01

    Ultrafine aerosol particles (smaller than 50 nanometers in diameter) have been thought to be too small to affect cloud formation. Fan et al. show that this is not the case. They studied the effect of urban pollution transported into the otherwise nearly pristine atmosphere of the Amazon. Condensational growth of water droplets around the tiny particles releases latent heat, thereby intensifying atmospheric convection. Thus, anthropogenic ultrafine aerosol particles may exert a more important influence on cloud formation processes than previously believed.

  19. The multi-component WKI hierarchy

    International Nuclear Information System (INIS)

    Yao Yuqin; Zhang Yufeng

    2005-01-01

    Firstly a new loop algebra G∼ M with 3M dimensions is constructed, which is devoted to establishing a new isospectral problem. Then the multi-component WKI hierarchy of soliton equations is obtained

  20. Novel energy sharing collisions of multicomponent solitons

    Indian Academy of Sciences (India)

    2015-10-21

    Oct 21, 2015 ... Abstract. In this paper, we discuss the fascinating energy sharing collisions of multicomponent solitons in certain incoherently coupled and coherently coupled nonlinear Schrödinger-type equations arising in the context of nonlinear optics.

  1. High Pressure Multicomponent Adsorption in Porous Media

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1999-01-01

    We analyse adsorption of a multicomponent mixture at high pressure on the basis of the potential theory of adsorption. The adsorbate is considered as a segregated mixture in the external field produced by a solid adsorbent. we derive an analytical equation for the thickness of a multicomponent film...... close to a dew point. This equation (asymptotic adsorption equation, AAE) is a first order approximation with regard to the distance from a phase envelope....

  2. Preparation of a ceramic superconductor from ultrafine particles by freeze-dry process in Ba-Y-Cu-O system

    International Nuclear Information System (INIS)

    Chen Zuyao; Qian Yitai; Wan Yanjian; Rong Jingfang; Zhang Han; Pan Guoqiang; Zhao Yong; Zhang Qirui

    1989-01-01

    Freeze-dry technique is first reported for preparing ceramic ultrafines. The single-phase complex oxide Ba 2 YCu 3 O/sub 9-δ/, a poly-crystallized compound, and ceramic superconductor have been synthesized successfully. The experimental results show that not only is the ceramic superconductor obtained uniform with fine particles and excellent superconductivity, but the conditions for solid reactions are relatively limited

  3. Size distribution and total number concentration of ultrafine and accumulation mode particles and hospital admissions in children and the elderly in Copenhagen, Denmark

    DEFF Research Database (Denmark)

    Andersen, Zorana Jovanovic; Wåhlin, Peter; Raaschou-Nielsen, O

    2008-01-01

    OBJECTIVES: To study the association between short-term exposure to ultrafine particles and morbidity in Copenhagen, Denmark. METHODS: We studied the association between urban background levels of the total number concentration of particles (NC(tot), 6-700 nm in diameter) measured at a single sit...

  4. Fluid description of multi-component solar partially ionized plasma

    Energy Technology Data Exchange (ETDEWEB)

    Khomenko, E., E-mail: khomenko@iac.es; Collados, M.; Vitas, N. [Instituto de Astrofísica de Canarias, 38205 La Laguna, Tenerife (Spain); Departamento de Astrofísica, Universidad de La Laguna, 38205 La Laguna, Tenerife (Spain); Díaz, A. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)

    2014-09-15

    We derive self-consistent formalism for the description of multi-component partially ionized solar plasma, by means of the coupled equations for the charged and neutral components for an arbitrary number of chemical species, and the radiation field. All approximations and assumptions are carefully considered. Generalized Ohm's law is derived for the single-fluid and two-fluid formalism. Our approach is analytical with some order-of-magnitude support calculations. After general equations are developed, we particularize to some frequently considered cases as for the interaction of matter and radiation.

  5. Diclofenac Sodium Loaded Multicomponent Implant

    Science.gov (United States)

    Nikkola, Lila; Viitanen, Petrus; Ashammakhi, Nureddin

    2008-02-01

    Earlier we have reported on developing DS releasing bioabsorbable rods for inhibition of osteolysis [l]. Due to their unsatisfactory drug release profiles we assessed the use of sintering technique of enhancement of drug release in the current study. Melt extruded PLGA 80/20 rods were compounded 8 wt-% DS. Some rods were self reinforced (SR) and some of them were sterilized to get three different components with different drug release profiles. Different rods were sintered together with heat and pressure. Three different specimen groups with different construction were studied. Thermal properties were analyzed using differential scanning calorimetry (DSC). Changes of IV were performed with capillary analysis and drug release measurements with UV-Vis spectrophotometer. Mechanical strength were measured two weeks, when disintegration occurred. Release rate consisted of 1) sharp jump start peak, 2) second smoother peak, and 3) third smooth peak. Released DS concentrations reached local therapeutic levels and maintained at that stage for 24-36 days. All DS was released during 50-70 days. The drug release from multicomponent implant was more stable and commenced earlier than from initial rods. Such properties were favored ones. Initial shear strength was 82 MPa and it decreased to 15 MPa. The mechanical bonding was sufficient although the components disintegrated relatively fast. By sintering different PLGA/DS components with different release rates it is possible to construct a truly controlled release implant for bone fixation with anti-inflammatory properties.

  6. PRM97 – Evaluating the cost-effectiveness of multicomponent rehabilitation guidelines

    NARCIS (Netherlands)

    Mewes, Janne; Steuten, Lotte Maria Gertruda; IJzerman, Maarten Joost; van Harten, Willem H.

    2013-01-01

    Objectives The Dutch guideline for cancer rehabilitation recommends patients to engage in multicomponent interventions, i.e. several single interventions combined into a rehabilitation programme. To perform a health economic evaluation of this guideline, data on the cost-effectiveness of these

  7. Thermodiffusion in Multicomponent Mixtures Thermodynamic, Algebraic, and Neuro-Computing Models

    CERN Document Server

    Srinivasan, Seshasai

    2013-01-01

    Thermodiffusion in Multicomponent Mixtures presents the computational approaches that are employed in the study of thermodiffusion in various types of mixtures, namely, hydrocarbons, polymers, water-alcohol, molten metals, and so forth. We present a detailed formalism of these methods that are based on non-equilibrium thermodynamics or algebraic correlations or principles of the artificial neural network. The book will serve as single complete reference to understand the theoretical derivations of thermodiffusion models and its application to different types of multi-component mixtures. An exhaustive discussion of these is used to give a complete perspective of the principles and the key factors that govern the thermodiffusion process.

  8. Transport processes in multicomponent plasma

    International Nuclear Information System (INIS)

    Zissis, G.

    2002-01-01

    Full text: This book treats in detail, as indicated in the title, the transport phenomena in multicomponent plasmas. Here, the term 'transport' applies to the study of mass and energy transfer in plasmas due to the interactions between pairs of particles only. Radiation is legitimately omitted; anyway, radiative transfer is another field of study. As the author himself mentions in the introduction, 'the term multicomponent plasma implies a partially or fully ionized mixture of arbitrary number of species of neutral and charged particles satisfying the condition of quasi-neutrality'. In fact, this book treats a large variety of plasmas applying to different systems ranging from low-pressure systems which may be far from local thermodynamic equilibrium (LTE) conditions, to thermal plasmas in LTE or near-LTE states with special attention to two-temperature systems; partially ionized plasmas with low ionization degree for which electron-neutral interactions are predominant, to systems with higher ionization degrees in which charged particle interactions are no more negligible. In addition, for all the above stated situations, the author treats both plasmas which are subjected to an external electromagnetic field and those which are not (homogeneous and inhomogeneous cases). Furthermore, in the last chapters a special discussion concerning molecular plasmas is presented. Taking into account the evolution of plasma modelling in the last few years, the subject is of current interest and the reader will find in the book a large amount of information necessary for a good understanding of transport phenomena in plasmas: for a plasma simulation specialist, this book may be regarded as reference text, which includes all necessary mathematical relations for his work. However, it should not be considered a simple formulary; the reader will also find here an excellent description of the theoretical basis necessary for the derivation of all given expressions. To this point of view

  9. Polymer degradation and ultrafine particles - Potential inhalation hazards for astronauts

    Science.gov (United States)

    Ferin, J.; Oberdoerster, G.

    1992-01-01

    To test the hypothesis that exposure to ultrafine particles results in an increased interstiatilization of the particles which is accompanied by an acute pathological inflammation, rats were exposed to titanium dioxide (TiO2) particles by intratracheal instillation and by inhalation. Both acute intratracheal instillation and subchronic inhalation studies on rats show that ultrafine TiO2 particles access the pulmonary interstitium to a larger extent than fine particles and that they elicit an inflammatory response as indicated by PMN increase in lavaged cells. The release of ultrafine particles into the air of an enclosed environment from a thermodegradation event or from other sources is a potential hazard for astronauts. Knowing the mechanisms of action is a prerequisite for technical or medical countermeasures.

  10. Surface integrity analysis when milling ultrafine-grained steels

    Directory of Open Access Journals (Sweden)

    Alessandro Roger Rodrigues

    2012-02-01

    Full Text Available This paper quantifies the effects of milling conditions on surface integrity of ultrafine-grained steels. Cutting speed, feed rate and depth of cut were related to microhardness and microstructure of the workpiece beneath machined surface. Low-carbon alloyed steel with 10.8 µm (as-received and 1.7 µm (ultrafine grain sizes were end milled using the down-milling and dry condition in a CNC machining center. The results show ultrafine-grained workpiece preserves its surface integrity against cutting parameters more than the as-received material. Cutting speed increases the microhardness while depth of cut deepens the hardened layer of the as-received material. Also, deformations of microstructure following feed rate direction were observed in workpiece subsurface.

  11. Fabrication of ultra-fine grained aluminium tubes by RTES technique

    Energy Technology Data Exchange (ETDEWEB)

    Jafarzadeh, H., E-mail: h.jafarzadeh@ut.ac.ir; Abrinia, K.

    2015-04-15

    Recently, repetitive tube expansion and shrinking have been exploited as a means for producing ultra-fine grained and nano-crystalline microstructures for magnesium alloy tubes. This method includes two different half-cycles and was based on pressing a tubular part through an angular channel die with two shear zones. Since the aluminium alloys are the most widely used materials in industries, in this study, repetitive tube expansion and shrinking as a new severe plastic deformation technique was applied to commercially pure aluminium for fabricating ultra-fine grained aluminium tubes for the first time and the ability of this process in significant grain refinement is determined even after single cycle. Transmission electron microscopy and X-ray diffraction were used to evaluate the microstructure of the repetitive tube expansion and shrinking processed materials and the examinations showed ultra-fine grains with the average grain size of 320 nm after one cycle of repetitive tube expansion and shrinking. The yield strength, ultimate tensile strength increased notably by the factor of 2.17 and 1.27 respectively, after one cycle of repetitive tube expansion and shrinking, whereas the elongation to failure as well as the uniform elongation decreased. Furthermore, micro-hardness distribution through the part's section proposed the hardness increasing to ~ 55 HV from the initial value of ~ 28 HV after one cycle of repetitive tube expansion and shrinking. - Highlights: • RTES was introduced for fabricating the UFGed AA1050 tubes for the first time. • Nano-grained AA1050 tube was obtained by RTES process. • Grain size of ~ 320 nm was obtained after two half-cycles of RTES process. • Yield and ultimate strength increased by the factor of 2.17 and 1.27 respectively. • The microhardness increased to ~ 55 HV from the initial value of ~ 28 HV.

  12. Preparation of Ultrafine Colloidal Gold Particles using a Bioactive Molecule

    Science.gov (United States)

    Pal, Anjali

    2004-02-01

    Synthesis of nanometer-sized particles with new physical properties is an area of tremendous interest. In metal particles, the changes in size modify the electron density in the particles, which shifts the plasmon band. The most significant size effects occur when the particles are ultrafine (size is synthesis of ultrafine metal particles is enormously important to exploit their unique and selective application. Here we report a novel method for the synthesis of ultrafine gold particles in the size range of 0.5-3 nm using dopamine hydrochloride (dhc), an important neurotransmitter. This is the first time where such an important bioactive molecule like dhc has been used as a reagent for the transformation of Au(III) to Au(0). The synthesis is carried out, for the first time, either in simple aqueous or in a nonionic micellar (for example Triton X-100 (TX-100)) medium. The gold sol has a beautiful yellow-brown color showing λmax at 470 nm. The appearance of the absorption peak at substantially shorter wavelength (usually gold sol absorbs at ˜520 nm) indicates that the particles are very small. The method discussed here is very simple, reproducible and does not involve any reagent, which contains 'P' or 'S' atoms. Also in this case no polymer or dendrimer or thiol-related stabilizer is used. The effects of different parameters (such as the presence or absence of O2, temperature, TX-100 concentration and dhc concentration) on the formation of ultrafine gold particles are discussed. The effects of 3-mercapto propionic acid and pyridine on the ultrafine gold sol are also studied and compared with those on photochemically prepared gold sol. It is observed that 3-mercapto propionic acid dampens the plasmon absorption at 470 nm of ultrafine gold particles. Pyridine, on the other hand, has no effect on the particles.

  13. Controllable microfluidic production of multicomponent multiple emulsions.

    Science.gov (United States)

    Wang, Wei; Xie, Rui; Ju, Xiao-Jie; Luo, Tao; Liu, Li; Weitz, David A; Chu, Liang-Yin

    2011-05-07

    A hierarchical and scalable microfluidic device constructed from a combination of three building blocks enables highly controlled generation of multicomponent multiple emulsions. The number, ratio and size of droplets, each with distinct contents being independently co-encapsulated in the same level, can be precisely controlled. The building blocks are a drop maker, a connector and a liquid extractor; combinations of these enable the scale-up of the device to create higher-order multicomponent multiple emulsions with exceptionally diverse structures. These multicomponent multiple emulsions offer a versatile and promising platform for precise encapsulation of incompatible actives or chemicals, for synergistic delivery and biochemical and chemical reactions, and for engineering multicompartment materials with controlled internal phases. © The Royal Society of Chemistry 2011

  14. Multicomponent equations of state for electrolytes

    DEFF Research Database (Denmark)

    Lin, Yi; Thomsen, Kaj; Hemptinne, Jean-Charles de

    2007-01-01

    equations of state, Peng-Robinson, Soave-Redlich-Kwong, or Cubic-Plus-Association (CPA). Long-range interactions are described by either the simplified mean spherical approximation (MSA) solution of the Ornstein-Zernicke equation or the simplified Debye-Huchel term. An optional Born term is added......Four equations of state have been implemented and evaluated for multicomponent electrolyte solutions at 298.15 K and 1 bar. The equations contain terms accounting for short-range and long-range interactions in electrolyte solutions. Short range interactions are described by one of the three...... to these electrostatic terms. The resulting electrolyte equations of state were tested by determining the optimal model parameters for the multicomponent test system consisting of H2O, Na+, H+, Ca2+, Cl-, OH-, SO42-. To describe the thermodynamics of this multicomponent system, ion specific parameters were determined...

  15. Numerical modeling of a vaporizing multicomponent droplet

    Science.gov (United States)

    Megaridis, C. M.; Sirignano, W. A.

    The fundamental processes governing the energy, mass, and momentum exchange between the liquid and gas phases of vaporizing, multicomponent liquid droplets have been investigated. The axisymmetric configuration under consideration consists of an isolated multicomponent droplet vaporizing in a convective environment. The model considers different volatilities of the liquid components, variable liquid properties due to variation of the species concentrations, and non-Fickian multicomponent gaseous diffusion. The bicomponent droplet model was employed to examine the commonly used assumptions of unity Lewis number in the liquid phase and Fickian gaseous diffusion. It is found that the droplet drag coefficients, the vaporization rates, and the related transfer numbers are not influenced by the above assumptions in a significant way.

  16. Twinning interactions induced amorphisation in ultrafine silicon grains

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Y. [School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Zhang, L.C., E-mail: liangchi.zhang@unsw.edu.au [School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052 (Australia); Zhang, Y. [School of Mechatronics Engineering, Harbin Institute of Technology (China)

    2016-03-21

    Detailed transmission electron microscopy analysis on a severely deformed Al-Si composite material has revealed that partial dislocation slips and deformation twinning are the major plastic deformation carriers in ultrafine silicon grains. This resembles the deformation twinning activities and mechanisms observed in nano-crystalline face-centred-cubic metallic materials. While deformation twinning and amorphisation in Si were thought unlikely to co-exist, it is observed for the first time that excessive twinning and partial dislocation interactions can lead to localised solid state amorphisation inside ultrafine silicon grains.

  17. A chemical analyzer for charged ultrafine particles

    Science.gov (United States)

    Gonser, S. G.; Held, A.

    2013-09-01

    New particle formation is a frequent phenomenon in the atmosphere and of major significance for the Earth's climate and human health. To date the mechanisms leading to the nucleation of particles as well as to aerosol growth are not completely understood. A lack of appropriate measurement equipment for online analysis of the chemical composition of freshly nucleated particles is one major limitation. We have developed a Chemical Analyzer for Charged Ultrafine Particles (CAChUP) capable of analyzing particles with diameters below 30 nm. A bulk of size-separated particles is collected electrostatically on a metal filament, resistively desorbed and subsequently analyzed for its molecular composition in a time of flight mass spectrometer. We report on technical details as well as characterization experiments performed with the CAChUP. Our instrument was tested in the laboratory for its detection performance as well as for its collection and desorption capabilities. The manual application of defined masses of camphene (C10H16) to the desorption filament resulted in a detection limit between 0.5 and 5 ng, and showed a linear response of the mass spectrometer. Flow tube experiments of 25 nm diameter secondary organic aerosol from ozonolysis of alpha-pinene also showed a linear relation between collection time and the mass spectrometer's signal intensity. The resulting mass spectra from the collection experiments are in good agreement with published work on particles generated by the ozonolysis of alpha-pinene. A sensitivity study shows that the current setup of CAChUP is ready for laboratory measurements and for the observation of new particle formation events in the field.

  18. Multiphase, multicomponent phase behavior prediction

    Science.gov (United States)

    Dadmohammadi, Younas

    Accurate prediction of phase behavior of fluid mixtures in the chemical industry is essential for designing and operating a multitude of processes. Reliable generalized predictions of phase equilibrium properties, such as pressure, temperature, and phase compositions offer an attractive alternative to costly and time consuming experimental measurements. The main purpose of this work was to assess the efficacy of recently generalized activity coefficient models based on binary experimental data to (a) predict binary and ternary vapor-liquid equilibrium systems, and (b) characterize liquid-liquid equilibrium systems. These studies were completed using a diverse binary VLE database consisting of 916 binary and 86 ternary systems involving 140 compounds belonging to 31 chemical classes. Specifically the following tasks were undertaken: First, a comprehensive assessment of the two common approaches (gamma-phi (gamma-ϕ) and phi-phi (ϕ-ϕ)) used for determining the phase behavior of vapor-liquid equilibrium systems is presented. Both the representation and predictive capabilities of these two approaches were examined, as delineated form internal and external consistency tests of 916 binary systems. For the purpose, the universal quasi-chemical (UNIQUAC) model and the Peng-Robinson (PR) equation of state (EOS) were used in this assessment. Second, the efficacy of recently developed generalized UNIQUAC and the nonrandom two-liquid (NRTL) for predicting multicomponent VLE systems were investigated. Third, the abilities of recently modified NRTL model (mNRTL2 and mNRTL1) to characterize liquid-liquid equilibria (LLE) phase conditions and attributes, including phase stability, miscibility, and consolute point coordinates, were assessed. The results of this work indicate that the ϕ-ϕ approach represents the binary VLE systems considered within three times the error of the gamma-ϕ approach. A similar trend was observed for the for the generalized model predictions using

  19. Preparation and Characterization of Plasma-Sprayed Ultrafine Chromium Oxide Coatings

    International Nuclear Information System (INIS)

    Lin Feng; Jiang Xianliang; Yu Yueguang; Zeng Keli; Ren Xianjing; Li Zhenduo

    2007-01-01

    Ultrafine chromium oxide coatings were prepared by plasma spraying with ultrafine feedstock. Processing parameters of plasma spraying were optimized. Optical microscope (OM) was used to observe the microstructure of the ultrafine chromium oxide coatings. Scanning electron microscopy (SEM) was used to observe the morphology and particle size of ultrafine powder feedstock as well as to examine the microstructure of the chromium oxide coating. In addition, hardness and bonding strength of the ultrafine chromium oxide coatings were measured. The results showed that the optimized plasma spraying parameters were suitable for ultrafine chromium oxide coating and the properties and microstructure of the optimized ultrafine chromium oxide coating were superior compared to conventional chromium oxide wear resistant coatings

  20. Strategies for innovation in multicomponent reaction design.

    Science.gov (United States)

    Ganem, Bruce

    2009-03-17

    By generating structural complexity in a single step from three or more reactants, multicomponent reactions (MCRs) make it possible to synthesize target compounds with greater efficiency and atom economy. The history of such reactions can be traced to the mid-19th century when Strecker first produced alpha-aminonitriles from the condensation of aldehydes with ammonia and hydrogen cyanide. Recently, academic chemists have renewed their interest in MCRs. In part, the pharmaceutical industry has fueled this resurgence because of the growing need to assemble libraries of structurally complex substances for evaluation as lead compounds in drug discovery and development programs. The application of MCRs to that increasingly important objective remains limited by the relatively small number of such reactions that can be broadly applied to prepare biologically relevant or natural-product-like molecular frameworks. We were interested in applying logic-based approaches, such as our single reactant replacement (SRR) approach, as a way both to improve known MCRs and to design new multiple-component routes to bioactive structures. This Account provides several examples that illustrate the use of SRR with known MCRs as starting points for synthetic innovation in this area. As part of our working hypothesis, we initially explored strategies for engineering improvements into known MCRs, either by increasing the dimensionality--that is, changing an n-component to an (n + 1)-component reaction--or broadening the scope of useful input structures, or both. By exhaustively applying retrosynthetic analysis to the cognate MCR to identify and exploit alternative entry points into the overall reaction manifold, we have devised several such re-engineered MCRs. Serendipitous findings have also augmented the yield of useful developments from our logic-inspired approach. In some cases, we have identified surprising links between different compound families that provide useful new entry points

  1. Production of ultrafine sumatriptan succinate particles for pulmonary delivery.

    Science.gov (United States)

    Yang, Zong-Yang; Le, Yuan; Hu, Ting-Ting; Shen, Zhigang; Chen, Jian-Feng; Yun, Jimmy

    2008-09-01

    Drug particle physical properties are critical for the efficiency of a drug delivered to the lung. The purpose of this study was to produce ultrafine sumatriptan succinate particles for inhalation. Sumatriptan succinate particles were produced via reactive precipitation without any surfactants. Several low toxic organic solvents such as acetone, isopropanol, and tetrahydrofuran were investigated as the reaction medium. And the dry powder was obtained via spray drying. FT-IR, HPLC, SEM and XRD were exploited to characterize the physicochemical properties of the ultrafine sumatriptan succinate dry powder. The aerosol performance of the powder was evaluated using an Aeroliser connected to a multi stage liquid impinger operating at 60 l/min. The mean particle size of the ultrafine sumatriptan succinate particles obtained under optimum conditions was in the range of 630-679 nm and consequently they were in the respirable range. The spray-dried powder whose fine particle fraction was increased up to 50.6 +/- 8.2% showed good aerosol performance whereas the vacuum-dried powder was approximate 18.2 +/- 3.0%. Good aerosol performance ultrafine sumatriptan succinate particles could be produced by reactive precipitation without any additives followed by spray drying at the optimum parameters.

  2. Polymer degradation and ultrafine particles: Potential inhalation hazards for astronauts

    Science.gov (United States)

    Ferin, J.; Oberdörster, G.

    When Teflon is heated the developing fumes produce in exposed humans an influenza-like syndrome (polymer fume fever) or also severe toxic effects like pulmonary edema, pneumonitis and death. The decomposition products and the resulting health effects are temperature-dependent. The toxic effects seem to be related to the ultrafine particulate fraction of the fume. To test the hypothesis that exposure to ultrafine particles results in an increased interstitialization of the particles which is accompanied by an acute pathological inflammation, rats were exposed to titanium dioxide (TiO 2) particles by intratracheal instillation and by inhalation. Both acute intratracheal instillation and subchronic inhalation studies on rats show that ultrafine TiO 2 particles (˜20 nm diameter) access the pulmonary interstitium to a larger extent than fine particles (˜250 nm diameter) and that they elicit an inflammatory response as indicated by PMN increase in lavaged cells. The release of ultrafine particles into the air of an enclosed environment from a thermodegradation event or from other sources is a potential hazard for astronauts. Knowing the mechanisms of action is a prerequisite for technical or medical countermeasures.

  3. Separation of ultrafine particles from class F fly ashes

    Directory of Open Access Journals (Sweden)

    Acar Ilker

    2016-01-01

    Full Text Available In this study, ultrafine particles were recovered from Çatalağzı (CFA and Sugözü (SFA thermal power plant fly ashes using a specific hydraulic classification technology. Since fly ashes have a high tendency to be flocculated in water, settling experiments were first designed to determine the more effective dispersant and the optimum dosage. Two different types of the superplasticizers (SP polymers based on sulphonate (NSF, Disal and carboxylate (Glenium 7500 were used as the dispersing agents in these settling experiments. Hydraulic classification experiments were then conducted to separate ultrafine fractions from the fly ash samples on the basis of the settling experiments. According to the settling experiments, better results were achieved with the use of Disal for both CFA and SFA. The classification experiments showed that the overflow products with average particle sizes of 5.2 μm for CFA and 4.4 μm for SFA were separated from the respective as-received samples with acceptable yields and high enough recoveries of -5 μm (ultrafine particles. Overall results pointed out that the hydraulic classification technology used provided promising results in the ultrafine particle separations from the fly ash samples.

  4. Outdoor ultrafine particle concentrations in front of fast food restaurants

    NARCIS (Netherlands)

    Vert, Cristina; Meliefste, Kees; Hoek, Gerard

    2016-01-01

    Ultrafine particles (UFPs) have been associated with negative effects on human health. Emissions from motor vehicles are the principal source of UFPs in urban air. A study in Vancouver suggested that UFP concentrations were related to density of fast food restaurants near the monitoring sites. A

  5. Initiation of fatigue cracks in ultrafine-grained copper

    Czech Academy of Sciences Publication Activity Database

    Lukáš, Petr; Kunz, Ludvík; Navrátilová, Lucie

    2012-01-01

    Roč. 50, č. 6 (2012), s. 407-419 ISSN 0023-432X Institutional support: RVO:68081723 Keywords : ultrafine-grained microstructure * fatigue * slip bands * microcrack initiation * grain coarsening Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.687, year: 2012

  6. Benchmarks for multicomponent diffusion and electrochemical migration

    DEFF Research Database (Denmark)

    Rasouli, Pejman; Steefel, Carl I.; Mayer, K. Ulrich

    2015-01-01

    In multicomponent electrolyte solutions, the tendency of ions to diffuse at different rates results in a charge imbalance that is counteracted by the electrostatic coupling between charged species leading to a process called “electrochemical migration” or “electromigration.” Although not commonly...... with the three reactive transport codes used: CrunchFlow, MIN3P, and PHREEQC....

  7. Multicomponent Reactions, Union of MCRs and Beyond

    NARCIS (Netherlands)

    Zarganes-Tzitzikas, Tryfon; Chandgude, Ajay L; Dömling, Alexander

    2015-01-01

    Multicomponent reactions (MCRs), which are located between one- and two-component and polymerization reactions, provide a number of valuable conceptual and synthetic advantages over stepwise sequential approaches towards complex and valuable molecules. To address current limitations in the number of

  8. Novel energy sharing collisions of multicomponent solitons

    Indian Academy of Sciences (India)

    2015-10-21

    Oct 21, 2015 ... In this paper, we discuss the fascinating energy sharing collisions of multicomponent solitons in certain incoherently coupled and coherently coupled ... Post Graduate and Research Department of Physics, Bishop Heber College, Tiruchirappalli 620 017, India; Department of Physics, Anna University, ...

  9. Catalysis and Multi-Component Reactions

    Science.gov (United States)

    Shibasaki, Masakatsu; Yus, Miguel; Bremner, Stacy; Comer, Eamon; Shore, Gjergji; Morin, Sylvie; Organ, Michael G.; van der Eycken, Erik; Merkul, Eugen; Dorsch, Dieter; Müller, Thomas J. J.; Ryabukhin, Sergey V.; Ostapchuk, Eugeniy N.; Plaskon, Andrey S.; Volochnyuk, Dmitriy M.; Shivanyuk, Alexander N.; Tolmachev, Andrey A.; Sheibani, Hassan; Babaie, Maryam; Behzadi, Soheila; Dabiri, Minoo; Bahramnejad, Mahboobeh; Bashiribod, Sahareh; Hekmatshoar, Rahim; Sadjadi, Sodeh; Khorasani, Mohammad; Polyakov, Anatoliy I.; Eryomina, Vera A.; Medvedeva, Lidiya A.; Tihonova, Nadezhda I.; Listratova, Anna V.; Voskressensky, Leonid G.; Merkul, Eugen; Dorsch, Dieter; Müller, Thomas J. J.; Sheibani, Hassan; Esfandiarpoor, Zeinab; Behzadi, Soheila; Titova, Julia A.; Fedorova, Olga V.; Ovchinnikova, Irina G.; Valova, Marina S.; Koryakova, Olga V.; Rusinov, Gennady L.; Charushin, Valery N.; Hekmatshoar, Rahim; Sadjadi, Sodeh

    We have been studying the development of new asymmetric two-center catalysis using rare earth alkoxides and bifunctional sugar and related ligands. In The Fourth International Conference on Multi-Component Reactions and Related Chemistry (MCR 2009), new catalytic asymmetric reactions using catalysts 1 and 2 and catalytic asymmetric syntheses of ranirestat 3 and tamiflu 4 will be presented.

  10. Microreactor Technology as an Efficient Tool for Multicomponent Reactions

    Science.gov (United States)

    Cukalovic, Ana; Monbaliu, Jean-Christophe M. R.; Stevens, Christian V.

    Multicomponent reactions are an important tool in organic synthesis as they often allow the circumvention of multistep procedures by combining three or more molecules into one structure in a single step. An additional asset of the approach is the significant increase of the combinatorial possibilities, since a modification of the final product is easily accomplished by implementing minor changes in the reaction setup; this obviously allows considerable savings in time and resources. These advantages are of particular interest in pharmaceutical research for the construction of libraries. In order to increase the sustainability of chemical processes, the field is intensively explored, and novel reactions are frequently reported. Microreactor technology also offers a contemporary way of conducting chemical reactions in a more sustainable fashion due to the miniaturization and increased safety, and also in a technically improved manner due to intensified process efficiency. This relatively new technology is implemented in novel and improved applications and is getting more and more used in chemical research. The combination of the benefits from the two approaches clearly presents an attractive reaction design, and this chapter presents an overview of the reported examples in which the microreactor technology and the multicomponent approach are combined, usually with dramatically improved results compared to those previously reported.

  11. Multicomponent density functional theory embedding formulation.

    Science.gov (United States)

    Culpitt, Tanner; Brorsen, Kurt R; Pak, Michael V; Hammes-Schiffer, Sharon

    2016-07-28

    Multicomponent density functional theory (DFT) methods have been developed to treat two types of particles, such as electrons and nuclei, quantum mechanically at the same level. In the nuclear-electronic orbital (NEO) approach, all electrons and select nuclei, typically key protons, are treated quantum mechanically. For multicomponent DFT methods developed within the NEO framework, electron-proton correlation functionals based on explicitly correlated wavefunctions have been designed and used in conjunction with well-established electronic exchange-correlation functionals. Herein a general theory for multicomponent embedded DFT is developed to enable the accurate treatment of larger systems. In the general theory, the total electronic density is separated into two subsystem densities, denoted as regular and special, and different electron-proton correlation functionals are used for these two electronic densities. In the specific implementation, the special electron density is defined in terms of spatially localized Kohn-Sham electronic orbitals, and electron-proton correlation is included only for the special electron density. The electron-proton correlation functional depends on only the special electron density and the proton density, whereas the electronic exchange-correlation functional depends on the total electronic density. This scheme includes the essential electron-proton correlation, which is a relatively local effect, as well as the electronic exchange-correlation for the entire system. This multicomponent DFT-in-DFT embedding theory is applied to the HCN and FHF(-) molecules in conjunction with two different electron-proton correlation functionals and three different electronic exchange-correlation functionals. The results illustrate that this approach provides qualitatively accurate nuclear densities in a computationally tractable manner. The general theory is also easily extended to other types of partitioning schemes for multicomponent systems.

  12. In-cabin ultrafine particle dynamics

    Science.gov (United States)

    Xu, Bin

    To assess the total human health risks associated with human exposure to ultrafine particle (UFP), the concentrations and fates of UFPs in the in-cabin atmospheres must be understood. In order to assess human exposure more accurately and further prevent adverse health effects from UFP exposure in the in-cabins, it is essential to gain insight into UFP transport dynamics between in-cabin and outside atmospheres and the factors that are able to affect them. In this dissertation, mathematical model are developed and formulated as tools to improve the understanding of UFP dynamics in the in-cabin atmosphere. Under three different ventilation conditions, (i) Fan off-recirculation (RC) off, (ii) Fan on-RC off, and (iii) Fan on-RC on, the average modeled UFP I/O ratios were found to be 0.40, 0.25 and 0.10, respectively, and agree with the experimental data very well. Then, analysis focused on how the factors, such as ventilation settings, vehicle speed, filtration, penetration, and deposition, affect I/O ratios in broader categories of vehicle cabin microenvironments. Ventilation is the only mechanical process of exchanging air between the in-cabin and the outside. Under condition (ii), I/O ratio that varies from 0.2 to 0.7 was proportional to the airflow rate in the range of 0-360 m3/h. Under condition (iii), the modeled I/O ratio was inversely proportional to the airflow rate from mechanical ventilation within the range of 0.15-0.45 depending on the particle size. Significant variability of the penetration factor (5˜20%) was found due to the pressure difference. A coefficient "B" was successfully introduced to account for the electric charge effect on penetration factors. The effect of penetration on the I/O ratio was then evaluated by substituting penetration factor into the model. Under condition (i), the modeled I/O ratios increased linearly, up to ˜20%, within the penetration factor range. Under condition (iii), the effect of penetration factor is less but still

  13. Preparation and pattern recognition of metallic Ni ultrafine powders by electroless plating

    International Nuclear Information System (INIS)

    Zhang, H.J.; Zhang, H.T.; Wu, X.W.; Wang, Z.L.; Jia, Q.L.; Jia, X.L.

    2006-01-01

    Using hydrazine hydrate as reductant, metallic Ni ultrafine powders were prepared from NiSO 4 aqueous solution by electroless plating method. The factors including concentration of NiSO 4 , bathing temperature, ratio of hydrazine hydrate to NiSO 4 , the pH of the solution, etc., on influence of the yield and average particle size of metallic Ni ultrafine powders were studied in detail. X-ray powders diffraction patterns show that the nickel powders are cubic crystallite. The average crystalline size of the ultrafine nickel powders is about 30 nm. The dielectric and magnetic loss of ultrafine Ni powders-paraffin wax composites were measured by the rectangle waveguide method in the range 8.2-12.4 GHz. The factors for Ni ultrafine powders preparation are optimized by computer pattern recognition program based on principal component analysis, the optimum factors regions with higher yield of metallic Ni ultrafine powders are indicated by this way

  14. Multicomponent patterned ultrathin carbon nanomembranes by laser ablation

    Science.gov (United States)

    Frese, Natalie; Scherr, Julian; Beyer, André; Terfort, Andreas; Gölzhäuser, Armin; Hampp, Norbert; Rhinow, Daniel

    2018-01-01

    Carbon nanomembranes (CNMs) are a class of two-dimensional materials, which are obtained by electron beam-induced crosslinking of aromatic self-assembled monolayers (SAMs) on solid substrates. CNMs made from a single type of precursor molecule are uniform with homogeneous chemical and physical properties. We have developed a method for the fabrication of internally patterned CNMs resembling a key feature of biological membranes. Direct laser patterning is used to obtain multicomponent patterned SAMs on gold, which are subsequently crosslinked by electron irradiation. We demonstrate that the structure of internally patterned CNMs is preserved upon transfer to different substrates. The method enables rapid fabrication of patterned 2D materials with local variations in chemical and physical properties on the micrometer to centimeter scale.

  15. Martensitic Transformation in Ultrafine-Grained Stainless Steel AISI 304L Under Monotonic and Cyclic Loading

    Directory of Open Access Journals (Sweden)

    Heinz Werner Höppel

    2012-02-01

    Full Text Available The monotonic and cyclic deformation behavior of ultrafine-grained metastable austenitic steel AISI 304L, produced by severe plastic deformation, was investigated. Under monotonic loading, the martensitic phase transformation in the ultrafine-grained state is strongly favored. Under cyclic loading, the martensitic transformation behavior is similar to the coarse-grained condition, but the cyclic stress response is three times larger for the ultrafine-grained condition.

  16. Multi-component optical solitary waves

    DEFF Research Database (Denmark)

    Kivshar, Y. S.; Sukhorukov, A. A.; Ostrovskaya, E. A.

    2000-01-01

    We discuss several novel types of multi-component (temporal and spatial) envelope solitary waves that appear in fiber and waveguide nonlinear optics. In particular, we describe multi-channel solitary waves in bit-parallel-wavelength fiber transmission systems for highperformance computer networks......, multi-color parametric spatial solitary waves due to cascaded nonlinearities of quadratic materials, and quasiperiodic envelope solitons due to quasi-phase-matching in Fibonacci optical superlattices. (C) 2000 Elsevier Science B.V. All rights reserved....

  17. Tunneling-percolation model of multicomponent nanocomposites

    Science.gov (United States)

    Kale, Sohan; Karimi, Pouyan; Sabet, Fereshteh A.; Jasiuk, Iwona; Ostoja-Starzewski, Martin

    2018-02-01

    Using a mixture of different types of fillers has been experimentally shown to improve the electrical conductivity of polymer nanocomposites beyond the weighted average due to synergistic effects. In this study, we develop a critical path analysis-based tunneling-percolation model for multicomponent systems of nanocomposites with ellipsoidal fillers. The nature of the interaction between different filler components is controlled by a key modeling parameter capturing the tunneling interactions between fillers. This generalization allows us to examine scenarios where the nature of a given type of filler can be varied continuously from an insulating-type to a conductive-type. The percolation behavior of two-component systems with a combination of prolate, oblate, and spherical fillers is investigated using Monte Carlo simulations for different relative volume fractions and nature of interactions while keeping the total volume fraction fixed. The simulation results are shown to be in semi-quantitative agreement with predictions made by the second-virial-approximation-based theories. Our results suggest that for multicomponent systems with well-dispersed fillers, the synergistic effects are linked directly with the nature of interactions between different filler types. Moreover, addition of prolate fillers to oblate or spherical fillers should generally improve the electrical conductivity of multicomponent nanocomposites.

  18. Constitutive modeling of strain rate effects in nanocrystalline and ultrafine grained polycrystals

    KAUST Repository

    Gurses, Ercan

    2011-05-01

    We present a variational two-phase constitutive model capable of capturing the enhanced rate sensitivity in nanocrystalline (nc) and ultrafine-grained (ufg) fcc metals. The nc/ufg-material consists of a grain interior phase and a grain boundary affected zone (GBAZ). The behavior of the GBAZ is described by a rate-dependent isotropic porous plasticity model, whereas a rate-independent crystal-plasticity model which accounts for the transition from partial dislocation to full dislocation mediated plasticity is employed for the grain interior. The scale bridging from a single grain to a polycrystal is done by a Taylor-type homogenization. It is shown that the enhanced rate sensitivity caused by the grain size refinement is successfully captured by the proposed model. © 2011 Elsevier Ltd. All rights reserved.

  19. Ultrafine ferromagnetic iron oxide nanoparticles: Facile synthesis by low temperature decomposition of iron glycerolate

    Energy Technology Data Exchange (ETDEWEB)

    Bartůněk, Vilém, E-mail: vilem.bartunek@vscht.cz [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, 166 28 Prague 6 (Czech Republic); Průcha, David [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, 166 28 Prague 6 (Czech Republic); Švecová, Marie [Department of Analytical Chemistry, Faculty of Chemical Engineering, University of Chemistry and Technology, Technická 5, 166 28 Prague 6 (Czech Republic); Ulbrich, Pavel [Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Huber, Štěpán; Sedmidubský, David; Jankovský, Ondřej [Department of Inorganic Chemistry, Faculty of Chemical Technology, University of Chemistry and Technology, Technická 5, 166 28 Prague 6 (Czech Republic)

    2016-09-01

    We synthesized dark colored ultrafine – sub 10 nm iron oxide nanoparticles by a facile and low temperature process based on thermal decomposition of an affordable precursor – iron glycerolate. Simultaneous thermal analysis (STA) was used to study the thermal behaviour during the decomposition. The iron glycerolate was thoroughly analysed by various methods. The size of the iron nanoparticles was determined from XRD patterns and by transmission electron microscopy (TEM) and their composition has been confirmed by XPS. Magnetic properties of the nanoparticles were studied by vibrating sample magnetometry. The prepared single phase material exhibiting ferromagnetic properties is usable in a wide range of applications and may be suitable even for large scale industrial applications. - Highlights: • Iron glycerolate prepared and characterised. • Iron oxide nanoparticles prepared by thermal decomposition of iron glycerolate. • STA used to study the decomposition. • Products characterised by XRD, XPS, FT-IR, SEM and TEM. • Magnetic behaviour of monophasic samples determined.

  20. Activation of corn cellulose with alcohols to improve its dissolvability in fabricating ultrafine fibers via electrospinning.

    Science.gov (United States)

    Chen, Haizhen; Ni, Jinping; Chen, Jing; Xue, Wenwen; Wang, Jinggang; Na, Haining; Zhu, Jin

    2015-06-05

    Water and four small molecular alcohols are respectively used to activate corn cellulose (CN cellulose) with the aim to improve the dissolvability in DMAc/LiCl. Among all these activated agents, monohydric alcohols are found to produce the optimal effect of activation in the whole process including of activating, dissolving, and electrospinning of CN cellulose. Meanwhile, well distributed fibers with the diameter of 500nm-2μm are fabricated in electrospinning. Understanding the activation effect of monohydric alcohols with water and polyhydric alcohols, the most effective activated agent is ascertained with the characteristics of small molecular size, low viscosity, and single functionality. This work is definitely initiated to understand the critical principle of CN cellulose in dissolving. Accordingly, a feasible methodology is also established to prepare ultrafine cellulose fibers with good morphology in electrospinning. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Enhanced Antifungal Bioactivity of Coptis Rhizome Prepared by Ultrafining Technology

    Directory of Open Access Journals (Sweden)

    Ping-Chung Kuo

    2014-01-01

    Full Text Available The aim of this study was to identify and quantify the bioactive constituents in the methanol extracts of Coptis Rhizome prepared by ultrafining technology. The indicator compound was identified by spectroscopic method and its purity was determined by HPLC. Moreover, the crude extracts and indicator compound were examined for their ability to inhibit the growth of Rhizoctonia solani Kühn AG-4 on potato dextrose agar plates. The indicator compound is a potential candidate as a new plant derived pesticide to control Rhizoctonia damping-off in vegetable seedlings. In addition, the extracts of Coptis Rhizome prepared by ultrafining technology displayed higher contents of indicator compound; they not only improve their bioactivity but also reduce the amount of the pharmaceuticals required and, thereby, decrease the environmental degradation associated with the harvesting of the raw products.

  2. Commuter exposure to fine and ultrafine particulate matter in Vienna.

    Science.gov (United States)

    Strasser, Georg; Hiebaum, Stefan; Neuberger, Manfred

    2018-01-01

    Mass concentrations PM 10 , PM 2.5 , PM 1 , particle number concentrations of ultrafine particles and lung deposited surface area were measured during commutes with a subway, tram, bus, car and bicycle in Vienna for the first time. Obtained data were examined for significant differences in personal exposure when using various transport modalities along similar routes. Mean PM 2.5 and PM 1 mass concentrations were significantly higher in the subway when compared to buses. Mean PM 10 , PM 2.5 and PM 1 mass concentrations were significantly higher in the subway when compared to cars using low ventilation settings. Particle number concentrations of ultrafine particles were significantly higher in trams when compared to the subway and lung deposited surface area was significantly greater on bicycles when compared to the subway. After adjusting for different vehicle speeds, exposure to PM 10 , PM 2.5 and PM 1 along the same route length was significantly higher in the subway when compared to cars while exposure to ultrafine particles and partly also lung deposited surface area was significantly higher in bus, tram and on bicycle when compared to the subway. Car and bus passengers could be better isolated from ambient fine particulate matter than passengers in the subway, where a lot of ventilation occurs through open windows and larger doors. Tram passengers and cyclists might be exposed to increased amounts of ultrafine particles and larger lung deposited surface area due to a closer proximity to road traffic. Comparing cumulative exposure along the same route length leads to different results and favors faster traffic modes, such as the subway.

  3. Imaging of DNA Ultrafine Bridges in Budding Yeast.

    Science.gov (United States)

    Quevedo, Oliver; Lisby, Michael

    2018-01-01

    DNA ultrafine bridges (UFBs) are a type of chromatin-free DNA bridges that connect sister chromatids in anaphase and pose a threat to genome stability. However, little is known about the origin of these structures, and how they are sensed and resolved by the cell. In this chapter, we review tools and methods for studying UFBs by fluorescence microscopy including chemical and genetic approaches to induce UFBs in the model organism Saccharomyces cerevisiae.

  4. Microstructural response of ultrafine-grained copper to fatigue loading

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík; Lukáš, Petr; Buksa, Michal; Wang, Q.; Zheng, M.

    2007-01-01

    Roč. 13, č. 1 (2007), s. 512-518 ISSN 1335-1532. [Metallography 2007. Stará Lesná, 02.05.2007-04.05.2007] R&D Projects: GA MŠk(CZ) 1P05ME804 Institutional research plan: CEZ:AV0Z20410507 Keywords : Ultrafine-grained copper * Fatigue * Softening/hardening Subject RIV: JG - Metallurgy

  5. Sources of ultrafine particles in the Eastern United States

    Science.gov (United States)

    Posner, Laura N.; Pandis, Spyros N.

    2015-06-01

    Source contributions to ultrafine particle number concentrations for a summertime period in the Eastern U.S. are investigated using the chemical transport model PMCAMx-UF. New source-resolved number emissions inventories are developed for biomass burning, dust, gasoline automobiles, industrial sources, non-road and on-road diesel. According to the inventory for this summertime period in the Eastern U.S., gasoline automobiles are responsible for 40% of the ultrafine particle number emissions, followed by industrial sources (33%), non-road diesel (16%), on-road diesel (10%), and 1% from biomass burning and dust. With these emissions as input, the chemical transport model PMCAMx-UF reproduces observed ultrafine particle number concentrations (N3-100) in Pittsburgh with an error of 12%. For this summertime period in the Eastern U.S., nucleation is predicted to be the source of more than 90% of the total particle number concentrations. The source contributions to primary particle number concentrations are on average similar to those of their source emissions contributions: gasoline is predicted to contribute 36% of the total particle number concentrations, followed by industrial sources (31%), non-road diesel (18%), on-road diesel (10%), biomass burning (1%), and long-range transport (4%). For this summertime period in Pittsburgh, number source apportionment predictions for particles larger than 3 nm in diameter (traffic 65%, other combustion sources 35%) are consistent with measurement-based source apportionment (traffic 60%, combustion sources 40%).

  6. Activation of persulfate by irradiated laterite for removal of fluoroquinolones in multi-component systems

    OpenAIRE

    Kamagaté , M.; Amin Assadi , A.; Kone , T.; Coulibaly , L.; Hanna , K.

    2018-01-01

    International audience; Although several emerging contaminants (e.g. fluoro(quinolones) (FQs)) have been simultaneously detected in environmental systems, there is very limited information on their elimination from contaminated waters in multi-component systems. In this study, removal of three FQs including flumequine (FLU), ciprofloxacin (CIP) and norfloxacin (NOR) were investigated in single and mixture systems, using natural laterite soil and persulfate (PS) under UVA irradiation. Both sor...

  7. P-Link: A method for generating multicomponent cytochrome P450 fusions with variable linker length

    DEFF Research Database (Denmark)

    Belsare, Ketaki D.; Ruff, Anna Joelle; Martinez, Ronny

    2014-01-01

    Fusion protein construction is a widely employed biochemical technique, especially when it comes to multi-component enzymes such as cytochrome P450s. Here we describe a novel method for generating fusion proteins with variable linker lengths, protein fusion with variable linker insertion (P-LinK)...... but also requires only a single cloning and transformation step in order to generate multiple linker variants (1 to 16 amino acids long), making the approach technically simple and robust....

  8. Gleaning multicomponent T1 and T2 information from steady-state imaging data.

    Science.gov (United States)

    Deoni, Sean C L; Rutt, Brian K; Arun, Tarunya; Pierpaoli, Carlo; Jones, Derek K

    2008-12-01

    The driven-equilibrium single-pulse observation of T(1) (DESPOT1) and T(2) (DESPOT2) are rapid, accurate, and precise methods for voxelwise determination of the longitudinal and transverse relaxation times. A limitation of the methods, however, is the inherent assumption of single-component relaxation. In a variety of biological tissues, in particular human white matter (WM) and gray matter (GM), the relaxation has been shown to be more completely characterized by a summation of two or more relaxation components, or species, each believed to be associated with unique microanatomical domains or water pools. Unfortunately, characterization of these components on a voxelwise, whole-brain basis has traditionally been hindered by impractical acquisition times. In this work we extend the conventional DESPOT1 and DESPOT2 approaches to include multicomponent relaxation analysis. Following numerical analysis of the new technique, renamed multicomponent driven equilibrium single pulse observation of T(1)/T(2) (mcDESPOT), whole-brain multicomponent T(1) and T(2) quantification is demonstrated in vivo with clinically realistic times of between 16 and 30 min. Results obtained from four healthy individuals and two primary progressive multiple sclerosis (MS) patients demonstrate the future potential of the approach for identifying and assessing tissue changes associated with several neurodegenerative conditions, in particular those associated with WM. (c) 2008 Wiley-Liss, Inc.

  9. Multicomponent gas mixture air bearing modeling via lattice Boltzmann method

    Science.gov (United States)

    Tae Kim, Woo; Kim, Dehee; Hari Vemuri, Sesha; Kang, Soo-Choon; Seung Chung, Pil; Jhon, Myung S.

    2011-04-01

    As the demand for ultrahigh recording density increases, development of an integrated head disk interface (HDI) modeling tool, which considers the air bearing and lubricant film morphology simultaneously is of paramount importance. To overcome the shortcomings of the existing models based on the modified Reynolds equation (MRE), the lattice Boltzmann method (LBM) is a natural choice in modeling high Knudsen number (Kn) flows owing to its advantages over conventional methods. The transient and parallel nature makes this LBM an attractive tool for the next generation air bearing design. Although LBM has been successfully applied to single component systems, a multicomponent system analysis has been thwarted because of the complexity in coupling the terms for each component. Previous studies have shown good results in modeling immiscible component mixtures by use of an interparticle potential. In this paper, we extend our LBM model to predict the flow rate of high Kn pressure-driven flows in multicomponent gas mixture air bearings, such as the air-helium system. For accurate modeling of slip conditions near the wall, we adopt our LBM scheme with spatially dependent relaxation times for air bearings in HDIs. To verify the accuracy of our code, we tested our scheme via simple two-dimensional benchmark flows. In the pressure-driven flow of an air-helium mixture, we found that the simple linear combination of pure helium and pure air flow rates, based on helium and air mole fraction, gives considerable error when compared to our LBM calculation. Hybridization with the existing MRE database can be adopted with the procedure reported here to develop the state-of-the-art slider design software.

  10. Challenges and Approaches for Developing Ultrafine Particle Emission Inventories for Motor Vehicle and Bus Fleets

    Directory of Open Access Journals (Sweden)

    Diane U. Keogh

    2011-03-01

    Full Text Available Motor vehicles in urban areas are the main source of ultrafine particles (diameters < 0.1 µm. Ultrafine particles are generally measured in terms of particle number because they have little mass and are prolific in terms of their numbers. These sized particles are of particular interest because of their ability to enter deep into the human respiratory system and contribute to negative health effects. Currently ultrafine particles are neither regularly monitored nor regulated by ambient air quality standards. Motor vehicle and bus fleet inventories, epidemiological studies and studies of the chemical composition of ultrafine particles are urgently needed to inform scientific debate and guide development of air quality standards and regulation to control this important pollution source. This article discusses some of the many challenges associated with modelling and quantifying ultrafine particle concentrations and emission rates for developing inventories and microscale modelling of motor vehicles and buses, including the challenge of understanding and quantifying secondary particle formation. Recommendations are made concerning the application of particle emission factors in developing ultrafine particle inventories for motor vehicle fleets. The article presents a précis of the first published inventory of ultrafine particles (particle number developed for the urban South-East Queensland motor vehicle and bus fleet in Australia, and comments on the applicability of the comprehensive set of average particle emission factors used in this inventory, for developing ultrafine particle (particle number and particle mass inventories in other developed countries.

  11. Stability of ultrafine-grained structure of copper under fatigue loading

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík; Lukáš, Petr; Pantělejev, L.; Man, O.

    2011-01-01

    Roč. 10, - (2011), s. 201-206 E-ISSN 1877-7058 R&D Projects: GA ČR GAP108/10/2001 Institutional research plan: CEZ:AV0Z20410507 Keywords : fatigue of ultrafine-grained Cu * stability of ultrafine-grained structure * cyclic slip bands * shear bands Subject RIV: JL - Materials Fatigue, Friction Mechanics

  12. Producing of multicomponent and composite surface layers

    International Nuclear Information System (INIS)

    Wierzchon, T.; Bielinski, P.; Michalski, A.

    1995-01-01

    The paper presents a new method of producing multicomponent and composite layers on steel substrate. The combination of nickel plating with glow-discharge bordering or impulse-plasma deposition method gives an opportunity to obtain good properties of surface layers. The results of examinations of carbon 45 (0.45%C) steel, nickel plated and then borided under glow discharge conditions or covered with TiN layers are presented. The corrosion and friction wear resistance of such layers are markedly higher than for layer produced on non nickel plated substrates. (author). 19 refs, 5 figs

  13. Temperature dependence of nitrogen solubility in iron base multicomponent melts

    International Nuclear Information System (INIS)

    Sokolov, V.M.; Koval'chuk, L.A.

    1986-01-01

    Method for calculating temperature dependence of nitrogen solubility in iron base multicomponent melts is suggested. Application areas of existing methods were determined and advantages of the new method for calculating nitrogen solubility in multicomponent-doped iron melts (Fe-Ni-Cr-Mo, Fe-Ni-Cr-Mn, Fe-Mo-V) at 1773-2073 K are shown

  14. Immiscible multicomponent lattice Boltzmann model for fluids with ...

    Indian Academy of Sciences (India)

    ability to simulate immiscible multicomponent fluids with relaxation time ratio as large as 29.0 and to reduce 'spurious velocity'. In this work, the improved model is validated and studied using the central bubble case and the rising bubble case. It finds good applications in both static and dynamic cases for multicomponent ...

  15. Capabilities and limitations of predictive engineering theories for multicomponent adsorption

    DEFF Research Database (Denmark)

    Bartholdy, Sofie; Bjørner, Martin Gamel; Solbraa, Even

    2013-01-01

    ), and the multicomponent potential adsorption theory (MPTA). We have not attempted to improve/modify the methods in any way but have used them in their original form, as the purpose of our work is to illustrate the capabilities and inherent limitations of the models for predicting multicomponent adsorption. We have...

  16. Thermodynamics of the multicomponent vapor-liquid equilibrium under capillary pressure difference

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    2001-01-01

    We discuss the two-phase multicomponent equilibrium, provided that the phase pressures are different due to the action of capillary forces. We prove the two general properties of such an equilibrium, which have previously been known for a single-component case, however, to the best of our knowledge......, not for the multicomponent mixtures. The importance is emphasized on the space of the intensive variables P, T and mu (i), where the laws of capillary equilibrium have a simple geometrical interpretation. We formulate thermodynamic problems specific to such an equilibrium, and outline changes to be introduced to common...... algorithms of flash calculations in order to solve these problems. Sample calculations show large variation of the capillary properties of the mixture in the very neighborhood of the phase envelope and the restrictive role of the spinodal surface as a boundary for possible equilibrium states with different...

  17. [Establishment of modern multi-component sustained-release preparations of oral traditional Chinese medicines].

    Science.gov (United States)

    Xia, Hai-Jian; Zhang, Zhen-Hai; Liu, Dan; Yu, Dan-Hong; Jia, Xiao-Bin

    2013-10-01

    Traditional Chinese medicines have a long history, with a large quantity of efficient traditional Chinese medicines and prescriptions. However, the vast majority of pharmaceutical dose forms remain common preparations, with very few efficient, long-lasting and low-dose preparations. The sustain-release preparation allows sustained drug release in a longer period of time, maintains blood drug concentration, reduces the toxic effect and medication frequency, and improves medication compliance. Unlike monomer drugs, the material base of traditional Chinese medicine and compounds is multi-component, instead of single or several active monomers. Therefore, under the guidance of the Chinese medicine theories, modern multi-component sustained-release preparations were developed for oral traditional Chinese medicines, with the aim of finally improving the clinical efficacy of traditional Chinese medicines.

  18. Multicomponent semiconducting polymer systems with low crystallization-induced percolation threshold

    DEFF Research Database (Denmark)

    Goffri, S.; Müller, C.; Stingelin-Stutzmann, N.

    2006-01-01

    with the excellent mechanical properties of certain commodity polymers. Here we investigate bicomponent blends comprising semicrystalline regioregular poly(3-hexylthiophene) and selected semicrystalline commodity polymers, and show that, owing to a highly favourable, crystallization-induced phase segregation......–crystalline/semiconducting–insulating multicomponent systems offer expanded flexibility for realizing high-performance semiconducting architectures at drastically reduced materials cost with improved mechanical properties and environmental stability, without the need to design all performance requirements into the active semiconducting polymer......Blends and other multicomponent systems are used in various polymer applications to meet multiple requirements that cannot be fulfilled by a single material1, 2, 3. In polymer optoelectronic devices it is often desirable to combine the semiconducting properties of the conjugated species...

  19. [Impacts of multicomponent environment on solubility of puerarin in biopharmaceutics classification system of Chinese materia medica].

    Science.gov (United States)

    Hou, Cheng-Bo; Wang, Guo-Peng; Zhang, Qiang; Yang, Wen-Ning; Lv, Bei-Ran; Wei, Li; Dong, Ling

    2014-12-01

    To illustrate the solubility involved in biopharmaceutics classification system of Chinese materia medica (CMMBCS) , the influences of artificial multicomponent environment on solubility were investigated in this study. Mathematical model was built to describe the variation trend of their influence on the solubility of puerarin. Carried out with progressive levels, single component environment: baicalin, berberine and glycyrrhizic acid; double-component environment: baicalin and glycyrrhizic acid, baicalin and berberine and glycyrrhizic acid and berberine; and treble-component environment: baicalin, berberin, glycyrrhizic acid were used to describe the variation tendency of their influences on the solubility of puerarin, respectively. And then, the mathematical regression equation model was established to characterize the solubility of puerarin under multicomponent environment.

  20. Theory and Simulation of Multicomponent Osmotic Systems.

    Science.gov (United States)

    Karunaweera, Sadish; Gee, Moon Bae; Weerasinghe, Samantha; Smith, Paul E

    2012-05-28

    Most cellular processes occur in systems containing a variety of components many of which are open to material exchange. However, computer simulations of biological systems are almost exclusively performed in systems closed to material exchange. In principle, the behavior of biomolecules in open and closed systems will be different. Here, we provide a rigorous framework for the analysis of experimental and simulation data concerning open and closed multicomponent systems using the Kirkwood-Buff (KB) theory of solutions. The results are illustrated using computer simulations for various concentrations of the solutes Gly, Gly(2) and Gly(3) in both open and closed systems, and in the absence or presence of NaCl as a cosolvent. In addition, KB theory is used to help rationalize the aggregation properties of the solutes. Here one observes that the picture of solute association described by the KB integrals, which are directly related to the solution thermodynamics, and that provided by more physical clustering approaches are different. It is argued that the combination of KB theory and simulation data provides a simple and powerful tool for the analysis of complex multicomponent open and closed systems.

  1. Ultra-Fine Grained Dual-Phase Steels

    Directory of Open Access Journals (Sweden)

    Matthias Militzer

    2012-10-01

    Full Text Available This paper provides an overview on obtaining low-carbon ultra-fine grained dual-phase steels through rapid intercritical annealing of cold-rolled sheet as improved materials for automotive applications. A laboratory processing route was designed that involves cold-rolling of a tempered martensite structure followed by a second tempering step to produce a fine grained aggregate of ferrite and carbides as the initial microstructure for rapid intercritical annealing. The intercritical annealing step was performed with heating and cooling rates of at least 100 °C/s and a holding time of 30 s. The intercritical temperature was selected to result in 20- 35% martensite in the final microstructures for C-Mn steels with carbon contents of 0.06, 0.12 and 0.17 wt%, respectively. The proposed processing routes produced an ultra-fine grained ferrite-martensite structure withgrain sizes of approximately 1 ?m for all three steels. The tensile strength of these ultra-fine grained dualphase steels can be increased by up to 200 MPa as compared to coarse-grained dual-phase steels while maintaining uniform elongation values. The rather narrow processing window necessary to obtain these properties was evaluated by determining the effect of intercritical annealing conditions on microstructure evolution. Further, the experimental results were confirmed with phase field simulations of austenite formation indicating that rapid heat treatment cycles are essential to obtain fine grained intercritical austenite that leads to martensite islands with sizes of 1 ?m and below in the final microstructure.

  2. Method for the production of ultrafine particles by electrohydrodynamic micromixing

    Science.gov (United States)

    DePaoli, David W.; Hu, Zhong Cheng; Tsouris, Constantinos

    2001-01-01

    The present invention relates to a method for the rapid production of homogeneous, ultrafine inorganic material via liquid-phase reactions. The method of the present invention employs electrohydrodynamic flows in the vicinity of an electrified injector tube placed inside another tube to induce efficient turbulent mixing of two fluids containing reactive species. The rapid micromixing allows liquid-phase reactions to be conducted uniformly at high rates. This approach allows continuous production of non-agglomerated, monopispersed, submicron-sized, sphere-like powders.

  3. Surface structure and adsorption properties of ultrafine porous carbon fibers

    International Nuclear Information System (INIS)

    Song Xiaofeng; Wang Ce; Zhang Dejiang

    2009-01-01

    Ultrafine porous carbon fibers (UPCFs) were successfully synthesized by chemical activation of electrospun polyacrylonitrile fibers. In the current approach, potassium hydroxide was adopted as activation reagent. UPCFs were systematically evaluated by scanning electron microscope and nitrogen adsorption. The mass ratio of potassium hydroxide to preoxidized fibers, activation temperature and activation time are crucial for producing high quality UPCFs. The relationships between porous structure and process parameters are explored. UPCFs were applied as adsorbent for nitrogen monoxide to be compared with commercial porous carbon fibers.

  4. Personal exposure to ultrafine particles and oxidative DNA damage

    DEFF Research Database (Denmark)

    Vinzents, Peter S; Møller, Peter; Sørensen, Mette

    2005-01-01

    Exposure to ultrafine particles (UFPs) from vehicle exhaust has been related to risk of cardiovascular and pulmonary disease and cancer, even though exposure assessment is difficult. We studied personal exposure in terms of number concentrations of UFPs in the breathing zone, using portable...... the morning after exposure measurement. Cumulated outdoor and cumulated indoor exposures to UFPs each were independent significant predictors of the level of purine oxidation in DNA but not of strand breaks. Ambient air concentrations of particulate matter with an aerodynamic diameter of

  5. Facile Fabrication of Ultrafine Copper Nanoparticles in Organic Solvent

    Directory of Open Access Journals (Sweden)

    Siegert Uwe

    2009-01-01

    Full Text Available Abstract A facile chemical reduction method has been developed to fabricate ultrafine copper nanoparticles whose sizes can be controlled down to ca. 1 nm by using poly(N-vinylpyrrolidone (PVP as the stabilizer and sodium borohyrdride as the reducing agent in an alkaline ethylene glycol (EG solvent. Transmission electron microscopy (TEM results and UV–vis absorption spectra demonstrated that the as-prepared particles were well monodispersed, mostly composed of pure metallic Cu nanocrystals and extremely stable over extended period of simply sealed storage.

  6. GeoT User's Guide: A Computer Program for Multicomponent Geothermometry and Geochemical Speciation, Version 1.4

    Energy Technology Data Exchange (ETDEWEB)

    Spycher, Nicholas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Peiffer, Loic N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sonnenthal, Eric [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-04-10

    GeoT (Spycher et al., 2011) was developed by automating the multicomponent chemical geothermometry method of Reed and Spycher (1984). As needed, this program can be integrated with parameter estimation software. Without optimization, GeoT is useful for fast geothermometry computations with fluid compositions from single locations, and for independently processing fluids from multiple locations in one single program run.

  7. Ultrafine particles over Eastern Australia: an airborne survey

    Directory of Open Access Journals (Sweden)

    Wolfgang Junkermann

    2015-04-01

    Full Text Available Ultrafine particles (UFP in the atmosphere may have significant impacts on the regional water and radiation budgets through secondary effects on cloud microphysics. Yet, as these particles are invisible for current remote sensing techniques, knowledge about their three-dimensional distribution, source strengths and budgets is limited. Building on a 40-yr-old Australia-wide airborne survey which provides a reference case study of aerosol sources and budgets, this study presents results from a new airborne survey over Eastern Australia, northern New South Wales and Queensland. Observations identified apparent changes in the number and distribution of major anthropogenic aerosol sources since the early 1970s, which might relate to the simultaneously observed changes in rainfall patterns over eastern Queensland. Coal-fired power stations in the inland areas between Brisbane and Rockhampton were clearly identified as the major sources for ultrafine particulate matter. Sugar mills, smelters and shipping along the coast close to the Ports of Townsville and Rockhampton were comparable minor sources. Airborne Lagrangian plume studies were applied to investigate source strength and ageing properties within power station plumes. Significant changes observed, compared to the measurements in the 1970s, included a significant increase in the number concentration of UFP related to coal-fired power station emissions in the sparsely populated Queensland hinterland coincident with the area with the most pronounced reduction in rainfall.

  8. Directly electrospun ultrafine nanofibres with Cu grid spinneret

    International Nuclear Information System (INIS)

    Li Wenwang; Zheng Gaofeng; Wang Xiang; Wang Lingyun; Wang Han; Sun Daoheng; Zhang Yulong; Li Lei

    2011-01-01

    A hydrophobic Cu grid was used as an electrospinning spinneret to fabricate ultrafine organic nanofibres. The Cu grid used in this study was that which holds samples in TEM. Due to the hydrophobic surface and larger contact angle of the electrospinning solution on the Cu grid surface, the solution flow was divided into several finer ones by the holes in the Cu grid instead of accumulating. Each finer flow was stretched into individual jets and established a multi-jet mode by the electrical field force. The finer jets played an important role in decreasing the diameter of the nanofibre. The charge repulsion force among charged jets enhanced the whipping instability motion of the liquid jets, which improved the uniformity of the nanofibre and decreased the diameter of the nanofibre. An ultrafine uniform nanofibre of diameter less than 80 nm could be fabricated directly with the novel Cu grid spinneret without any additive. This study provided a unique way to promote the application of one-dimensional organic nanostructures in micro/nanosystems.

  9. Personal exposure to ultrafine particles and oxidative DNA damage

    DEFF Research Database (Denmark)

    Vinzents, Peter S; Møller, Peter; Sørensen, Mette

    2005-01-01

    Exposure to ultrafine particles (UFPs) from vehicle exhaust has been related to risk of cardiovascular and pulmonary disease and cancer, even though exposure assessment is difficult. We studied personal exposure in terms of number concentrations of UFPs in the breathing zone, using portable instr......, particularly during bicycling in traffic. The results indicate that biologic effects of UFPs occur at modest exposure, such as that occurring in traffic, which supports the relationship of UFPs and the adverse health effects of air pollution.......Exposure to ultrafine particles (UFPs) from vehicle exhaust has been related to risk of cardiovascular and pulmonary disease and cancer, even though exposure assessment is difficult. We studied personal exposure in terms of number concentrations of UFPs in the breathing zone, using portable...... instruments in six 18-hr periods in 15 healthy nonsmoking subjects. Exposure contrasts of outdoor pollution were achieved by bicycling in traffic for 5 days and in the laboratory for 1 day. Oxidative DNA damage was assessed as strand breaks and oxidized purines in mononuclear cells isolated from venous blood...

  10. On-chip multicomponent system made with an InGaN directional coupler.

    Science.gov (United States)

    Zhang, Fenghua; Shi, Zheng; Gao, Xumin; Qin, Chuan; Zhang, Shuai; Jiang, Yan; Wu, Fan; Wang, Yongjin

    2018-04-15

    An on-chip multicomponent system is implemented on a III-nitride-on-silicon platform by integrating a transmitter, InGaN waveguide, InGaN directional coupler, and receivers onto a single chip. The transmitter and the receiver share an identical InGaN/GaN multiple-quantum-well (MQW) diode structure and are produced by using the same wafer-level process flow. The receiver sensitively responds to the short-wavelength half of the emission spectrum of the transmitter, thus realizing the multicomponent system with the capability for inplane light communication. A SiO 2 isolation layer is employed to decrease the p-n junction capacitance, thus improving the modulation rate without modifying the MQW structure. The wire-bonded monolithic multicomponent system experimentally demonstrates inplane data transmission at 80 Mbps and spatial light communication at 100 Mbps, paving the way for diverse applications from on-chip power monitoring to inplane light communication in the visible light spectrum.

  11. A mesoscopic reaction rate model for shock initiation of multi-component PBX explosives.

    Science.gov (United States)

    Liu, Y R; Duan, Z P; Zhang, Z Y; Ou, Z C; Huang, F L

    2016-11-05

    The primary goal of this research is to develop a three-term mesoscopic reaction rate model that consists of a hot-spot ignition, a low-pressure slow burning and a high-pressure fast reaction terms for shock initiation of multi-component Plastic Bonded Explosives (PBX). Thereinto, based on the DZK hot-spot model for a single-component PBX explosive, the hot-spot ignition term as well as its reaction rate is obtained through a "mixing rule" of the explosive components; new expressions for both the low-pressure slow burning term and the high-pressure fast reaction term are also obtained by establishing the relationships between the reaction rate of the multi-component PBX explosive and that of its explosive components, based on the low-pressure slow burning term and the high-pressure fast reaction term of a mesoscopic reaction rate model. Furthermore, for verification, the new reaction rate model is incorporated into the DYNA2D code to simulate numerically the shock initiation process of the PBXC03 and the PBXC10 multi-component PBX explosives, and the numerical results of the pressure histories at different Lagrange locations in explosive are found to be in good agreements with previous experimental data. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. The effect of multi-component adsorption on selectivity in ion exchange displacement systems.

    Science.gov (United States)

    Tugcu, N; Cramer, S M

    2005-01-21

    This paper examines chemically selective displacement chromatography using affinity ranking plots, batch displacer screening experiments, column displacements, multi-component adsorption isotherms and spectroscopy. The affinity ranking plot indicated that the displacers, sucrose octasulfate (SOS) and tatrazine, should possess sufficient affinity to displace the proteins amyloglucosidase and apoferritin over a wide range of operating conditions. In addition, the plots indicated that the separation of these proteins by displacement chromatography would be extremely difficult. Further, the two proteins were shown to have very similar retention times under shallow linear gradient conditions. When batch displacement experiments were carried out, both tartrazine and SOS exhibited significant selectivity differences with respect to their ability to displace these two proteins, in contrast to the affinity ranking plot results. Column displacement experiments carried out with sucrose octasulfate agreed with the predictions of the affinity ranking plots, with both proteins being displaced but poorly resolved under several column displacement conditions. On the other hand, column displacement with tartrazine as the displacer resulted in the selective displacement and partial purification of apoferritin. Single- and multi-component isotherms of the proteins with or without the presence of displacers were determined and were used to help explain the selectivity reversals observed in the column and batch displacement experiments. In addition, fluorescence and CD spectra suggested that the displacers did not induce any structural changes to either of the proteins. The results in this paper indicate that multi-component adsorption behavior can be exploited for creating chemically selective displacement separations.

  13. Determination of Stability from Multicomponent Pesticide Mixes.

    Science.gov (United States)

    Dorweiler, Kelly J; Gurav, Jagdish N; Walbridge, James S; Ghatge, Vishwas S; Savant, Rahul H

    2016-08-10

    A study was conducted to evaluate the stability of 528 pesticides, metabolites, and contaminants prepared in large multicomponent mixes to enhance laboratory efficiency by allowing maximum use of the useful shelf life of the mixtures. Accelerated aging at 50 °C simulated 6 month, 1 year, and 2 year storage periods at -20 °C. Initial mixture composition was based on the instrument of analysis. After preliminary stability data had been obtained, mixtures were reformulated and re-evaluated. In all, 344 compounds showed satisfactory stability across all treatment groups, 100 compounds showed statistically significant changes between the control and the 6 month simulated storage period (27 with losses >20%), and the remainder showed borderline stability or were tested in one protocol. Stability behavior for organophosphates agreed with the proposed reaction mechanism responsible for acetylcholinesterase inhibition. A small number of compounds increased in response over time, suggesting the occurrence of degradation of precursor pesticides into these respective compounds.

  14. Reaction path simulations in multicomponent materials

    International Nuclear Information System (INIS)

    Seifert, H.J.

    1999-01-01

    The CALPHAD (calculation of phase diagrams) method is used in combination with selected experimental investigations to derive reaction paths in multicomponent systems. The method is illustrated by applying computerized thermodynamic databases and suitable software to explain quantitatively the thermal degradation of precursor-derived Si-C-N ceramics and the nitridation of titanium carbide. Reaction sequences in the Si 3 N 4 -SiC-TiC x N l-x -C-N system are illustrated by graphical representation of compatibility regions and indicated reaction paths. From these results the experimentally known microstructure development of TiC reinforced Si 3 N 4 ceramics is explained and quantitative information is provided to optimize the microstructure of such materials. The concept of reaction paths for the understanding of rapid solidification processes is shown by the example of AZ type Mg casting alloys. (orig.)

  15. Solidification in Multicomponent Multiphase Systems (SIMMS)

    Science.gov (United States)

    Rex, S.; Hecht, U.

    2005-06-01

    The multiphase microstructures that evolve during the solidification of multicomponent alloys are attracting widespread interest for industrial applications and fundamental research.Thermodynamic databases are now well-established for many alloy systems. Thermodynamic calculations provide all the required information about phase equilibria, forming an integral part of both dedicated and comprehensive microstructure models. Among the latter, phase-field modelling has emerged as the method of choice. Solidification experiments are intended to trigger model development or to serve as benchmarks for model validation. For benchmarking, microgravity conditions offer a unique opportunity for avoiding buoyancy-induced convection and buoyancy forces in bulk samples. However, diffusion and the free-energy of interfaces and its anisotropy need to be determined.The measurement of chemical diffusivities in the liquid state can equally benefit from microgravity experiments.

  16. Dynamic Multi-Component Hemiaminal Assembly

    Science.gov (United States)

    You, Lei; Long, S. Reid; Lynch, Vincent M.

    2012-01-01

    A simple approach to generating in situ metal templated tris-(2-picolyl)amine-like multi-component assemblies with potential applications in molecular recognition and sensing is reported. The assembly is based on the reversible covalent association between di-(2-picolyl)amine and aldehydes. Zinc ion is the best for inducing assembly among the metal salts investigated, while 2-picolinaldehyde is the best among the heterocyclic aldehydes studied. Although an equilibrium constant of 6.6 * 103 M-1 was measured for the assembly formed by 2-picolinaldehdye, di-(2-picolyl)amine, and zinc triflate, the equilibrium constants for other systems are in the 102 M-1 range. X-ray structural analysis revealed that zinc adopts a trigonal bipyramidal geometry within the assembled ligand. The diversity and equilibrium of the assemblies are readily altered by simply changing concentrations, varying components, or adding counter anions. PMID:21919095

  17. Stratification during evaporative assembly of multicomponent nanoparticle films.

    Science.gov (United States)

    Liu, Xiao; Liu, Weiping; Carr, Amanda J; Santiago Vazquez, Dayalis; Nykypanchuk, Dmytro; Majewski, Pawel W; Routh, Alexander F; Bhatia, Surita R

    2018-04-01

    Multicomponent coatings with layers comprising different functionalities are of interest for a variety of applications, including electronic devices, energy storage, and biomaterials. Rather than creating such a film using multiple deposition steps, we explore a single-step method to create such films by varying the particle Peclet numbers, Pe. Our hypothesis, based on recent theoretical descriptions of the stratification process, is that by varying particle size and evaporation rate such that Pe of large and small particles are above and below unity, we can create stratified films of polymeric and inorganic particles. We present AFM on the surface composition of films comprising poly(styrene) nanoparticles (diameter 25-90 nm) and silica nanoparticles (diameter 8-14 nm). Previous studies on films containing both inorganic and polymeric particles correspond to large Pe values (e.g., 120-460), while we utilize Pe ∼ 0.3-4, enabling us to test theories that have been developed for different regimes of Pe. We demonstrate evidence of stratification and effect of the Pe ratio, although our results agree only qualitatively with theory. Our results also provide validation of recent theoretical descriptions of the film drying process that predict different regimes for large-on-top and small-on-top stratification. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Ion channeling study of defects in multicomponent semiconductor compounds

    International Nuclear Information System (INIS)

    Turos, A.; Nowicki, L.; Stonert, A.

    2002-01-01

    Compound semiconductor crystals are of great technological importance as basic materials for production of modern opto- and microelectronic devices. Ion implantation is one of the principal techniques for heterostructures processing. This paper reports the results of the study of defect formation and transformation in binary and ternary semiconductor compounds subjected to ion implantation with ions of different mass and energy. The principal analytical technique was He-ion channeling. The following materials were studied: GaN and InGaN epitaxial layers. First the semi empirical method of channeling spectra analysis for ion implanted multicomponent single crystal was developed. This method was later complemented by the more sophisticated method based on the Monte Carlo simulation of channeling spectra. Next, the damage buildup in different crystals and epitaxial layers as a function of the implantation dose was studied for N, Mg, Te, and Kr ions. The influence of the substrate temperature on the defect transformations was studied for GaN epitaxial layers implanted with Mg ions. Special attention was devoted to the study of growth conditions of InGaN/GaN/sapphire heterostructures, which are important component of the future blue laser diodes. In-atom segregation and tetragonal distortion of the epitaxial layer were observed and characterized. Next problem studied was the incorporation of hydrogen atoms in GaAs and GaN. Elastic recoil detection (ERDA) and nuclear reaction analysis (NRA) were applied for the purpose. (author)

  19. Local stress calculation in simulations of multicomponent systems

    International Nuclear Information System (INIS)

    Branicio, Paulo S.; Srolovitz, David J.

    2009-01-01

    The virial and Hardy methods provide accurate local stresses for single component materials such as monatomic metals. In contrast to the elemental material case, both methods provide poor estimates of the local stress for multicomponent materials. Using binary materials such as CaO, SiC and AlN and homogeneous strain, we demonstrate that there are several sources for the slow convergence of the virial and Hardy local stresses to the bulk values. Different approaches such as enforced stoichiometry, atomic localization functions and the atomic voronoi volume are used to improve the convergence and increase the spatial resolution of the local stress. The virial method with enforced stoichiometry and atomic voronoi volumes is the most accurate, giving exact stress values by the first atomic shell. In the general case, not assuming stoichiometry, the virial method with localization functions converge to 93% of the bulk value by the third atomic shell. This work may be particularly useful for the real-time description of stresses in simulations of shock waves and deformation dynamics.

  20. Synthesis of conformationally constrained peptidomimetics using multicomponent reactions

    NARCIS (Netherlands)

    Scheffelaar, R.; Klein Nijenhuis, R.A.; Paravidino, M.; Lutz, M.|info:eu-repo/dai/nl/304828971; Spek, A.L.|info:eu-repo/dai/nl/156517566; Ehlers, A.W.; de Kanter, F.J.J.; Groen, M.B.; Orru, R.V.A.; Ruijter, E.

    2009-01-01

    A novel modular synthetic approach toward constrained peptidomimetics is reported. The approach involves a highly efficient three-step sequence including two multicomponent reactions, thus allowing unprecedented diversification of both the peptide moieties and the turn-inducing scaffold. The

  1. Synthesis of Conformationally Constrained Peptidomimetics using Multicomponent Reactions

    NARCIS (Netherlands)

    Scheffelaar, R.; Nijenhuis, R.A.K.; Paravidino, M.; Lutz, M.; Spek, A.L; Ehlers, A.W.; de Kanter, F.J.J.; Groen, M.B.; Orru, R.V.A.; Ruijter, E.

    2009-01-01

    A novel modular synthetic approach toward constrained peptidomimetics is reported. The approach involves a highly efficient three-step sequence including two multicomponent reactions, thus allowing unprecedented diversification of both the peptide moieties and the turn-inducing scaffold. The

  2. Seismic reservoir characterization: how can multicomponent data help?

    International Nuclear Information System (INIS)

    Li, Xiang-Yang; Zhang, Yong-Gang

    2011-01-01

    This paper discusses the concepts of multicomponent seismology and how it can be applied to characterize hydrocarbon reservoirs, illustrated using a 3D three-component real-data example from southwest China. Hydrocarbon reservoirs formed from subtle lithological changes, such as stratigraphic traps, may be delineated from changes in P- and S-wave velocities and impedances, whilst hydrocarbon reservoirs containing aligned fractures are anisotropic. Examination of the resultant split shear waves can give us a better definition of their internal structures. Furthermore, frequency-dependent variations in seismic attributes derived from multicomponent data can provide us with vital information about fluid type and distribution. Current practice and various examples have demonstrated the undoubted potential of multicomponent seismic in reservoir characterization. Despite all this, there are still substantial challenges ahead. In particular, the improvement and interpretation of converted-wave imaging are major hurdles that need to be overcome before multicomponent seismic becomes a mainstream technology

  3. Seismic reservoir characterization: how can multicomponent data help?

    Science.gov (United States)

    Li, Xiang-Yang; Zhang, Yong-Gang

    2011-06-01

    This paper discusses the concepts of multicomponent seismology and how it can be applied to characterize hydrocarbon reservoirs, illustrated using a 3D three-component real-data example from southwest China. Hydrocarbon reservoirs formed from subtle lithological changes, such as stratigraphic traps, may be delineated from changes in P- and S-wave velocities and impedances, whilst hydrocarbon reservoirs containing aligned fractures are anisotropic. Examination of the resultant split shear waves can give us a better definition of their internal structures. Furthermore, frequency-dependent variations in seismic attributes derived from multicomponent data can provide us with vital information about fluid type and distribution. Current practice and various examples have demonstrated the undoubted potential of multicomponent seismic in reservoir characterization. Despite all this, there are still substantial challenges ahead. In particular, the improvement and interpretation of converted-wave imaging are major hurdles that need to be overcome before multicomponent seismic becomes a mainstream technology.

  4. Zeolite H-BEA catalysed multicomponent reaction: One-pot ...

    Indian Academy of Sciences (India)

    BEA catalysed multicomponent reaction: One-pot synthesis of amidoalkyl naphthols - Biologically active drug-like molecules. Sunil R Mistry Rikesh S Joshi Kalpana C Maheria. Volume 123 Issue 4 July 2011 pp 427-432 ...

  5. [Effect of multicomponent environment on intestinal permeability of puerarin in biopharmaceutics classification system of Chinese materia medica].

    Science.gov (United States)

    Liu, Yang; Wang, Gang; Dong, Ling; Tang, Ming-Min; Zhu, Mei-Ling; Dong, Hong-Huant; Hou, Cheng-Bo

    2014-12-01

    The evaluation of permeability in biopharmaceutics classification system of Chinese materia medica (CMMBCS) requires multicomponent as a whole in order to conduct research, even in the study of a specific component, should also be put in the multicomponent environment. Based on this principle, the high content components in Gegen Qinlian decoction were used as multicomponent environmental impact factors in the experiment, and the relevant parameters of intestinal permeability about puerarin were measured with using in situ single-pass intestinal perfusion model, to investigate and evaluate the intestinal permeability of puerarin with other high content components. The experimental results showed that different proportions of baicalin, glycyrrhizic acid and berberine had certain influence on intestinal permeability of puerarin, and glycyrrhizic acid could significantly inhibit the intestinal absorption of puerarin, moreover, high concentration of berberine could promote the absorption of puerarin. The research results indicated that the important research ideas of permeability evaluation in biopharmaceutics classification system of Chinese materia medica with fully considering the effects of other ingredients in multicomponent environment.

  6. Ultrafine Particulate Matter Increases Cardiac Ischemia/Reperfusion Injury via Mitochondrial Permeability Transition Pore.

    Science.gov (United States)

    Ultrafine Particulate Matter (UFP) has been associated with increased cardiovascular morbidity and mortality. However, the mechanisms that drive PM associated cardiovascular disease and dysfunction remain unclear. We examined the impact of intratracheal instillation of 100 ᠊...

  7. Personal exposure to ultrafine particles in the workplace: Exploring sampling techniques and strategies

    NARCIS (Netherlands)

    Brouwer, D.H.; Gijsbers, J.H.J.; Lurvink, M.W.M.

    2004-01-01

    Recently, toxicological and epidemiological studies on health effects related to particle exposure suggest that 'ultrafine particles' (particles with an aerodynamic diameter of <100 nm) may cause severe health effects after inhalation. Although the toxicological mechanisms for these effects have not

  8. Characterization of ultrafine and fine particles from CHP Plants

    Energy Technology Data Exchange (ETDEWEB)

    2009-08-15

    Samples of particles collected at CHP plants in the project 'Survey of emissions from CHP Plants' have been analysed in this project to give information on the morphology and chemical composition of individual particle size classes. The objective of this project was to characterize ultrafine and fine particles emitted to the atmosphere from Danish CHP plants. Nine CHP plants were selected in the Emission Survey Project as being representative for the different types of CHP plants operating in Denmark: 1) Three Waste-to Energy (WTE) plants. 2) Three biomass fired (BM) plants (two straw fired, one wood/saw dust fired). 3) Two gas fired (GF) plants (one natural gas, one landfill gas fired). 4) One gasoil (GO) fired plant. At the WTE and BM plants, various types of emission control systems implemented. The results from these plants represent the composition and size distribution of combustion particles that are emitted from the plants emission control systems. The measured emissions of particles from the waste-to-energy plants WTE1-3 are generally very low. The number and mass concentrations of ultrafine particles (PM{sub 0.1}) were particularly low in the flue gas from WTE2 and WTE3, where bag filters are used for the reduction of particle emissions. The EDX analysis of particles from the WTE plants indicates that the PM{sub 0.1} that penetrates the ECS at WTE can contain high fractions of metals such as Fe, Mn and Cu. The SEM analysis of particles from WTE1-3 showed that the particles were generally porous and irregular in shape. The concentrations of particles in the flue gas from the biomass plants were generally higher than found for the WTE plants. The time series results showed that periodical, high concentration peaks of PM emissions occur from BM1 and BM2. The chemical composition of the particles emitted from the three biomass plants is generally dominated by C, O and S, and to some extend also Fe and Si. A high amount of Cu was found in selected

  9. Deposition of fine and ultrafine particles on indoor surface materials

    DEFF Research Database (Denmark)

    Afshari, Alireza; Reinhold, Claus

    2008-01-01

    -scale test chamber. Experiments took place in a 32 m3 chamber with walls and ceiling made of glass. Prior to each experiment the chamber was flushed with outdoor air to reach an initial particle concentration typical of indoor air in buildings with natural ventilation. The decay of particle concentrations...... The aim of this study was the experimental determination of particle deposition for both different particle size fractions and different indoor surface materials. The selected surface materials were glass, gypsum board, carpet, and curtain. These materials were tested vertically in a full...... was monitored. Seven particle size fractions were studied. These comprised ultrafine and fine particles. Deposition was higher on carpet and curtain than on glass and gypsum board. Particles ranging from 0.3 to 0.5 µm had the lowest deposition. This fraction also has the highest penetration and its indoor...

  10. Substantial convection and precipitation enhancements by ultrafine aerosol particles

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Jiwen; Rosenfeld, Daniel; Zhang, Yuwei; Giangrande, Scott E.; Li, Zhanqing; Machado, Luiz A. T.; Martin, Scot T.; Yang, Yan; Wang, Jian; Artaxo, Paulo; Barbosa, Henrique M. J.; Braga, Ramon C.; Comstock, Jennifer M.; Feng, Zhe; Gao, Wenhua; Gomes, Helber B.; Mei, Fan; Pöhlker, Christopher; Pöhlker, Mira L.; Pöschl, Ulrich; de Souza, Rodrigo A. F.

    2018-01-25

    Aerosol-cloud interaction remains the largest uncertainty in climate projections. Ultrafine aerosol particles (UAP; size <50nm) are considered too small to serve as cloud condensation nuclei conventionally. However, this study provides observational evidence to accompany insights from numerical simulations to support that deep convective clouds (DCCs) over Amazon have strong capability of nucleating UAP from an urban source and forming greater numbers of droplets, because fast drop coalescence in these DCCs reduces drop surface area available for condensation, leading to high vapor supersaturation. The additional droplets subsequently decrease supersaturation and release more condensational latent heating, a dominant contributor to convection intensification, whereas enhanced latent heat from ice-related processes plays a secondary role. Therefore, the addition of anthropogenic UAP may play a much greater role in modulating clouds than previously believed over the Amazon region and possibly in other relatively pristine regions such as maritime and forest locations.

  11. Monotonic and cyclic deformation behaviour of ultrafine-grained aluminium

    International Nuclear Information System (INIS)

    May, J.; Amberger, D.; Dinkel, M.; Hoeppel, H.W.; Goeken, M.

    2008-01-01

    The effect of the enhanced strain-rate sensitivity (SRS) of ultrafine-grained commercially pure aluminium Al 99.5 on the mechanical properties under monotonic as well as under cyclic loading was investigated. Compared with the conventional grain-sized counterpart, for the monotonic tests, a strongly enhanced strength combined with a high ductility was obtained, depending on the strain rate. The enhanced SRS also affects the cyclic deformation behaviour and the fatigue lives. At a lower strain rate shorter fatigue lives and a different cyclic hardening behaviour are observed. Microstructural changes during cyclic deformation are investigated by X-ray diffraction profile analysis. Based on the fatigue behaviour and the X-ray diffraction profile analysis, thermally activated annihilation processes of dislocations are regarded to be the relevant deformation mechanism leading to enhanced SRS and ductility

  12. Preparation of Ni-C Ultrafine Composite from Waste Material

    Directory of Open Access Journals (Sweden)

    Mahmoud A. Rabah

    2017-06-01

    Full Text Available This work depicts the preparation of Ni-C ultrafine composite from used engine oil. The used oil was emulsified with detergent loaded with Ni (OH2. The loaded emulsion was sprayed on electric plasma generated between two C electrodes to a DC main 28 V and 70-80 A. The purged Ni-doped carbon fume was trapped on a polymer film moistened with synthetic adhesive to fix the trapped smoke. Characterization of the deposit was made using SEM. XRD examined the crystal morphology. Carbon density in the cloud was calculated. The average size and thickness of the deposited composite is 120-160 nm. Aliphatic hydrocarbons readily decompose to gaseous products. Solid carbon smoke originates from aromatic compounds. Plasma heat blasts the oil in short time to decompose in one step.

  13. Surface engineering of ultrafine cellulose nanofibrils toward polymer nanocomposite materials.

    Science.gov (United States)

    Fujisawa, Shuji; Saito, Tsuguyuki; Kimura, Satoshi; Iwata, Tadahisa; Isogai, Akira

    2013-05-13

    Surface grafting of crystalline and ultrafine cellulose nanofibrils with poly(ethylene glycol) (PEG) chains via ionic bonds was achieved by a simple ion-exchange treatment. The PEG-grafted cellulose nanofibrils exhibited nanodispersibility in organic solvents such as chloroform, toluene, and tetrahydrofuran. Then, the PEG-grafted cellulose nanofibril/chloroform dispersion and poly(L-lactide) (PLLA)/chloroform solution were mixed, and the PEG-grafted cellulose nanofibril/PLLA composite films with various blend ratios were prepared by casting the mixtures on a plate and drying. The tensile strength, Young's modulus, and work of fracture of the composite films were remarkably improved, despite low cellulose addition levels (cellulose nanofibrils in the PLLA matrix. Moreover, some attractive interactions mediated by the PEG chains were likely to be formed between the cellulose nanofibrils and PLLA molecules in the composites, additionally enhancing the efficient nanocomposite effect.

  14. Multi-component fiber track modelling of diffusion-weighted magnetic resonance imaging data

    Directory of Open Access Journals (Sweden)

    Yasser M. Kadah

    2010-01-01

    Full Text Available In conventional diffusion tensor imaging (DTI based on magnetic resonance data, each voxel is assumed to contain a single component having diffusion properties that can be fully represented by a single tensor. Even though this assumption can be valid in some cases, the general case involves the mixing of components, resulting in significant deviation from the single tensor model. Hence, a strategy that allows the decomposition of data based on a mixture model has the potential of enhancing the diagnostic value of DTI. This project aims to work towards the development and experimental verification of a robust method for solving the problem of multi-component modelling of diffusion tensor imaging data. The new method demonstrates significant error reduction from the single-component model while maintaining practicality for clinical applications, obtaining more accurate Fiber tracking results.

  15. Dark-matter decay as a complementary probe of multicomponent dark sectors.

    Science.gov (United States)

    Dienes, Keith R; Kumar, Jason; Thomas, Brooks; Yaylali, David

    2015-02-06

    In single-component theories of dark matter, the 2→2 amplitudes for dark-matter production, annihilation, and scattering can be related to each other through various crossing symmetries. The detection techniques based on these processes are thus complementary. However, multicomponent theories exhibit an additional direction for dark-matter complementarity: the possibility of dark-matter decay from heavier to lighter components. We discuss how this new detection channel may be correlated with the others, and demonstrate that the enhanced complementarity which emerges can be an important ingredient in probing and constraining the parameter spaces of such models.

  16. Detection of multicomponent signals: effect of difference in level between components.

    Science.gov (United States)

    Dubois, Françoise; Meunier, Sabine; Rabau, Guy; Poisson, Franck; Guyader, Gaël

    2011-11-01

    The detection of multicomponent signals for which the components are not equidetectable is precisely investigated as a function of the level difference ΔL(i∕j) between components. The detection thresholds are determined for a seven-tone complex signal with random starting phases masked by white noise. Level differences between the components are examined. A model for non-equidetectable conditions based on the statistical summation model is described. The improvement in detection is calculated from the level difference between components that is related to the thresholds for single components. The model predictions are in accordance with the experimental results.

  17. Application of an Ultrafine Shearing Method for the Extraction of C-Phycocyanin from Spirulina platensis

    Directory of Open Access Journals (Sweden)

    Jianfeng Yu

    2017-11-01

    Full Text Available Cell disruption is an important step during the extraction of C-phycocyanin from Spirulina platensis. An ultrafine shearing method is introduced and combined with soaking and ultrasonication to disrupt the cell walls of S. platensis efficiently and economically. Five kinds of cell disruption method, including soaking, ultrasonication, freezing-thawing, soaking-ultrafine shearing and soaking-ultrafine shearing-ultrasonication were applied to break the cell walls of S. platensis. The effectiveness of cell breaking was evaluated based on the yield of the C-phycocyanin. The results show that the maximum C-phycocyanin yield was 9.02%, achieved by the soaking-ultrafine shearing-ultrasonication method, followed by soaking (8.43%, soaking-ultrafine shearing (8.89%, freezing and thawing (8.34%, and soaking-ultrasonication (8.62%. The soaking-ultrafine shearing-ultrasonication method is a novel technique for breaking the cell walls of S. platensis for the extraction of C-phycocyanin.

  18. Novel Ultrafine Fibrous Poly(tetrafluoroethylene Hollow Fiber Membrane Fabricated by Electrospinning

    Directory of Open Access Journals (Sweden)

    Qinglin Huang

    2018-04-01

    Full Text Available Novel poly(tetrafluoroethylene (PTFE hollow fiber membranes were successfully fabricated by electrospinning, with ultrafine fibrous PTFE membranes as separation layers, while a porous glassfiber braided tube served as the supporting matrix. During this process, PTFE/poly(vinylalcohol (PVA ultrafine fibrous membranes were electrospun while covering the porous glassfiber braided tube; then, the nascent PTFE/PVA hollow fiber membrane was obtained. In the following sintering process, the spinning carrier PVA decomposed; meanwhile, the ultrafine fibrous PTFE membrane shrank inward so as to further integrate with the supporting matrix. Therefore, the ultrafine fibrous PTFE membranes had excellent interface bonding strength with the supporting matrix. Moreover, the obtained ultrafine fibrous PTFE hollow fiber membrane exhibited superior performances in terms of strong hydrophobicity (CA > 140°, high porosity (>70%, and sharp pore size distribution. The comprehensive properties indicated that the ultrafine fibrous PTFE hollow fiber membranes could have potentially useful applications in membrane contactors (MC, especially membrane distillation (MD in harsh water environments.

  19. Application of an Ultrafine Shearing Method for the Extraction of C-Phycocyanin from Spirulina platensis.

    Science.gov (United States)

    Yu, Jianfeng

    2017-11-21

    Cell disruption is an important step during the extraction of C-phycocyanin from Spirulina platensis . An ultrafine shearing method is introduced and combined with soaking and ultrasonication to disrupt the cell walls of S. platensis efficiently and economically. Five kinds of cell disruption method, including soaking, ultrasonication, freezing-thawing, soaking-ultrafine shearing and soaking-ultrafine shearing-ultrasonication were applied to break the cell walls of S. platensis . The effectiveness of cell breaking was evaluated based on the yield of the C-phycocyanin. The results show that the maximum C-phycocyanin yield was 9.02%, achieved by the soaking-ultrafine shearing-ultrasonication method, followed by soaking (8.43%), soaking-ultrafine shearing (8.89%), freezing and thawing (8.34%), and soaking-ultrasonication (8.62%). The soaking-ultrafine shearing-ultrasonication method is a novel technique for breaking the cell walls of S. platensis for the extraction of C-phycocyanin.

  20. An evaporation model of multicomponent solution drops

    Science.gov (United States)

    Sartori, Silvana; Liñán, Amable; Lasheras, Juan C.

    2010-11-01

    Solutions of polymers are widely used in the pharmaceutical industry as tablets coatings. These allow controlling the rate at which the drug is delivered, taste or appearance. The coating is performed by spraying and drying the tablets at moderate temperatures. The wetting of the coating solution on the pill's surface depends on the droplet Webber and Re numbers, angle of impact and on the rheological properties of the droplet. We present a model for the evaporation of multicomponent solutions droplets in a hot air environment with temperatures substantially lower than the boiling temperature of the solvent. As the liquid vaporizes from the surface the fluid in the drop increases in concentration, until reaching its saturation point. After saturation, precipitation occurs uniformly within the drop. As the surface regresses, a compacting front formed by the precipitate at its maximum packing density advances into the drop, while the solute continues precipitating uniformly. This porous shell grows fast due to the double effect of surface regression and precipitation. The evaporation rate is determined by the rates at which heat is transported to the droplet surface and at which liquid vapor diffuses away from it. When the drop is fully compacted, the evaporation is drastically reduced.

  1. Principles of Transport in Multicomponent Plasmas

    Science.gov (United States)

    Kaganovich, Igor D.; Franklin, Raoul N.; Demidov, Vladimir I.

    The main principles of transport in multicomponent plasmas are described. Because the bulk plasma is charged positively to keep electrons together with positive ions, negative ions are confined by electrostatic fields inside the plasma and they flow from the plasma periphery toward the center. It is shown that the flow velocity of negative ions is a nonlinear function of the negative ion density. Increasing the negative ion density makes the electron density profile flatter and leads to a decrease of the electric field. Such a nonlinear dependence of the negative ion flow velocity on their density results in the formation of steep gradients of negative ion density, or negative ion fronts. Addition of negative ions makes the plasma afterglow a complex process as well. Typically, two stages of afterglow appear. In the first stage, the negative ions are trapped inside the plasma and only electrons and positive ions can reach the walls. However, at a later time, electrons quickly leave the plasma, and the second stage of afterglow begins, in which electrons are totally absent and an ion-ion plasma forms. During this stage, only the negative and positive ions contribute to the wall fluxes. The complex structure of the radio frequency sheath in strongly electronegative gases is also reviewed. Similar phenomena are observed in dusty plasmas. A possible relevance to ball lightning is discussed.

  2. Spectral analysis in overmodulated holographic reflection gratings recorded with BB640 ultrafine grain emulsion

    Science.gov (United States)

    Mas-Abellán, P.; Madrigal, R.; Fimia, A.

    2015-05-01

    Silver halide emulsions have been considered one of the most energetic sensitive materials for holographic applications. Nonlinear recording effects on holographic reflection gratings recorded on silver halide emulsions have been studied by different authors obtaining excellent experimental results. In this communication specifically we focused our investigation on the effects of refractive index modulation, trying to get high levels of overmodulation. We studied the influence of the grating thickness on the overmodulation and its effects on the transmission spectra for a wide exposure range by use of two different thickness ultrafine grain emulsion BB640, thin films (6 μm) and thick films (9 μm), exposed to single collimated beams using a red He-Ne laser (wavelength 632.8 nm) with Denisyuk configuration obtaining a spatial frequency of 4990 l/mm recorded on the emulsion. The experimental results show that high overmodulation levels of refractive index could offer some benefits such as high diffraction efficiency (reaching 90 %), increase of grating bandwidth (close to 80 nm), making lighter holograms, or diffraction spectra deformation, transforming the spectrum from sinusoidal to approximation of square shape. Based on these results, we demonstrate that holographic reflection gratings spectra recorded with overmodulation of refractive index is formed by the combination of several non-linear components due to very high overmodulation. This study is the first step to develop a new easy multiplexing technique based on the use of high index modulation reflection gratings.

  3. Unresolved recombination intermediates lead to ultra-fine anaphase bridges, chromosome breaks and aberrations.

    Science.gov (United States)

    Chan, Ying Wai; Fugger, Kasper; West, Stephen C

    2018-01-01

    The resolution of joint molecules that link recombining sister chromatids is essential for chromosome segregation. Here, we determine the fate of unresolved recombination intermediates arising in cells lacking two nucleases required for resolution (GEN1 -/- knockout cells depleted of MUS81). We find that intermediates persist until mitosis and form a distinct class of anaphase bridges, which we term homologous recombination ultra-fine bridges (HR-UFBs). HR-UFBs are distinct from replication stress-associated UFBs, which arise at common fragile sites, and from centromeric UFBs. HR-UFBs are processed by BLM helicase to generate single-stranded RPA-coated bridges that are broken during mitosis. In the next cell cycle, DNA breaks activate the DNA damage checkpoint response, and chromosome fusions arise by non-homologous end joining. Consequently, the cells undergo cell cycle delay and massive cell death. These results lead us to present a model detailing how unresolved recombination intermediates can promote DNA damage and chromosomal instability.

  4. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    Energy Technology Data Exchange (ETDEWEB)

    James K. Neathery; Gary Jacobs; Amitava Sarkar; Burtron H. Davis

    2006-03-31

    The morphological and chemical nature of ultrafine iron catalyst particles (3-5 nm diameters) during activation/FTS was studied by HRTEM, EELS, and Moessbauer spectroscopy. With the progress of FTS, the carbide re-oxidized to magnetite and catalyst activity gradually decreased. The growth of oxide phase continued and average particle size also increased simultaneously. The phase transformation occurred in a ''growing oxide core'' manner with different nano-zones. The nano-range carbide particles did not show fragmentation or attrition as generally observed in micrometer range particles. Nevertheless, when the dimension of particles reached the micrometer range, the crystalline carbide phase appeared to be sprouted on the surface of magnetite single crystal. In the previous reporting period, a design and operating philosophy was developed for an integrated wax filtration system for a 4 liter slurry bubble column reactor to be used in Phase II of this research program. During the current reporting period, we have started construction of the new filtration system and began modifications to the 4 liter slurry bubble column reactor (SBCR) reactor. The system will utilize a primary wax separation device followed by a Pall Accusep or Membralox ceramic cross-flow membrane. As of this writing, the unit is nearly complete except for the modification of a moyno-type pump; the pump was shipped to the manufacturer to install a special leak-free, high pressure seal.

  5. Speciation and pulmonary effects of acidic SO x formed on the surface of ultrafine zinc oxide aerosols

    Science.gov (United States)

    Amdur, Mary O.; Chen, Lung Chi; Guty, John; Lam, Hua Fuan; Miller, Patricia D.

    Ultrafine metal oxides and SO 2 react during coal combustion or smelting operations to form primary emissions coated with an acidic SO x layer. A ZnO-SO 2-H 2O (mixed 500°C) system generates such particles to provide greatly needed information on both quantitative composition of the surface layer and its effects on the lung. Total S on the particles is related to ZnO concentration and is predominantly S VI. As a surface layer, 20 μg m -3 H 2SO 4 decreases pulmonary diffusing capacity in guinea pigs after four daily 3-h exposures and produces bronchial hypersensitivity following a single 1-h exposure. That 200 μg m -3 H 2SO 4 aerosols of equivalent particle size are needed to produce the same degree of bronchial hypersensitivity emphasizes the importance of the surface layer.

  6. Tuning the formation and functionalities of ultrafine CoFe2O4 nanocrystals via interfacial coherent strain

    Science.gov (United States)

    Hsieh, Ying-Hui; Kuo, Ho-Hung; Liao, Sheng-Chieh; Liu, Heng-Jui; Chen, Ying-Jiun; Lin, Hong-Ji; Chen, Chien-Te; Lai, Chih-Huang; Zhan, Qian; Chueh, Yu-Lun; Chu, Ying-Hao

    2013-06-01

    Complex oxide nanocrystals with a spinel structure show their remarkable optical, electronic, mechanical, thermal, and magnetic properties. In this study, we present a simple yet versatile strategy to grow self-assembled epitaxial CoFe2O4 nanocrystals with well-controlled size (less than 10 nm) and single orientation. CoFe2O4 nanocrystals were fabricated via phase separation in a BiFeO3-CoF2O4 ultrathin film by pulsed laser deposition. The coherent strain at the BiFeO3-CoF2O4 interface suppressed the growth of the nanocrystals regardless of substrate temperatures. This strain also resulted in the ferromagnetic anisotropy and interesting conducting behaviors of ultrafine CFO nanocrystals.

  7. Fabrication and characterization of dual-functional ultrafine composite fibers with phase-change energy storage and luminescence properties.

    Science.gov (United States)

    Xi, Peng; Zhao, Tianxiang; Xia, Lei; Shu, Dengkun; Ma, Menjiao; Cheng, Bowen

    2017-01-09

    Ultrafine composite fibers consisting of a thermoplastic polyurethane solid-solid phase-change material and organic lanthanide luminescent materials were prepared through a parallel electrospinning technique as an innovative type of ultrafine, dual-functional fibers containing phase-change and luminescent properties. The morphology and structure, thermal energy storage, and luminescent properties of parallel electrospun ultrafine fibers were investigated. Scanning electron microscopy (SEM) images showed that the parallel electrospun ultrafine fibers possessed the desired morphologies with smaller average fiber diameters than those of traditional mixed electrospun ultrafine fibers. Transmission electron microscopy (TEM) images revealed that the parallel electrospun ultrafine fibers were composed of two parts. Polymeric phase-change materials, which can be directly produced and spun, were used to provide temperature stability, while a mixture of polymethyl methacrylate and an organic lanthanide complex acted as the luminescent unit. Differential scanning calorimetry (DSC) and luminescence measurements indicated that the unique structure of the parallel electrospun ultrafine fibers provides the products with good thermal energy storage and luminescence properties. The fluorescence intensity and the phase-change enthalpy values of the ultrafine fibers prepared by parallel electrospinning were respectively 1.6 and 2.1 times those of ultrafine fibers prepared by mixed electrospinning.

  8. Modelling the phase equilibria of multicomponent mixtures containing CO2, alkanes, water, and/or alcohols using the quadrupolar CPA equation of state

    DEFF Research Database (Denmark)

    Bjørner, Martin Gamel; Kontogeorgis, Georgios

    2016-01-01

    In this work, a quadrupolar cubic plus association (qCPA) equation of state is evaluated for its ability to predict the phase equilibria of multicomponent mixtures containing CO2 and alkanes, alcohols, and/or water. A single binary interaction parameter is employed in qCPA for all binary...

  9. A Chemometrics-driven Strategy for the Bioactivity Evaluation of Complex Multicomponent Systems and the Effective Selection of Bioactivity-predictive Chemical Combinations.

    Science.gov (United States)

    Fujimura, Yoshinori; Kawano, Chihiro; Maeda-Murayama, Ayaka; Nakamura, Asako; Koike-Miki, Akiko; Yukihira, Daichi; Hayakawa, Eisuke; Ishii, Takanori; Tachibana, Hirofumi; Wariishi, Hiroyuki; Miura, Daisuke

    2017-05-23

    Although understanding their chemical composition is vital for accurately predicting the bioactivity of multicomponent drugs, nutraceuticals, and foods, no analytical approach exists to easily predict the bioactivity of multicomponent systems from complex behaviors of multiple coexisting factors. We herein represent a metabolic profiling (MP) strategy for evaluating bioactivity in systems containing various small molecules. Composition profiles of diverse bioactive herbal samples from 21 green tea extract (GTE) panels were obtained by a high-throughput, non-targeted analytical procedure. This employed the matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) technique, using 1,5-diaminonaphthalene (1,5-DAN) as the optical matrix for detecting GTE-derived components. Multivariate statistical analyses revealed differences among the GTEs in their antioxidant activity, oxygen radical absorbance capacity (ORAC). A reliable bioactivity-prediction model was constructed to predict the ORAC of diverse GTEs from their compositional balance. This chemometric procedure allowed the evaluation of GTE bioactivity by multicomponent rather than single-component information. The bioactivity could be easily evaluated by calculating the summed abundance of a few selected components that contributed most to constructing the prediction model. 1,5-DAN-MALDI-MS-MP, using diverse bioactive sample panels, represents a promising strategy for screening bioactivity-predictive multicomponent factors and selecting effective bioactivity-predictive chemical combinations for crude multicomponent systems.

  10. Multicomponent Protein Cage Architectures for Photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Arunava [Univ. of Alabama, Tuscaloosa, AL (United States); Prevelige, Peter E [Univ. of Alabama, Birmingham, AL (United States)

    2016-01-04

    The primary goal of the project was to develop protein-templated approaches for the synthesis and directed assembly of semiconductor nanomaterials that are efficient for visible light absorption and hydrogen production. In general, visible-light-driven photocatalysis reactions exhibit low quantum efficiency for solar energy conversion primarily because of materials-related issues and limitations, such as the control of the band gap, band structure, photochemical stability, and available reactive surface area of the photocatalyst. Synthesis of multicomponent hierarchical nano-architectures, consisting of semiconductor nanoparticles (NPs) with desired optical properties fabricated to maximize spatial proximity for optimum electron and energy transfer represents an attractive route for addressing the problem. Virus capsids are highly symmetrical, self-assembling protein cage nanoparticles that exist in a range of sizes and symmetries. Selective deposition of inorganic, by design, at specific locations on virus capsids affords precise control over the size, spacing, and assembly of nanomaterials, resulting in uniform and reproducible nano-architectures. We utilized the self-assembling capabilities of the 420 subunit, 60 nm icosahedral, P22 virus capsid to direct the nucleation, growth, and proximity of a range of component materials. Controlled fabrication on the exterior of the temperature stable shell was achieved by genetically encoding specific binding peptides into an externally exposed loop which is displayed on each of the 420 coat protein subunits. Localization of complimentary materials to the interior of the particle was achieved through the use “scaffolding-fusion proteins. The scaffolding domain drives coat protein polymerization resulting in a coat protein shell surrounding a core of approximately 300 scaffolding/fusion molecules. The fusion domain comprises a peptide which specifically binds the semiconductor material of interest.

  11. Multicomponent ensemble models to forecast induced seismicity

    Science.gov (United States)

    Király-Proag, E.; Gischig, V.; Zechar, J. D.; Wiemer, S.

    2018-01-01

    In recent years, human-induced seismicity has become a more and more relevant topic due to its economic and social implications. Several models and approaches have been developed to explain underlying physical processes or forecast induced seismicity. They range from simple statistical models to coupled numerical models incorporating complex physics. We advocate the need for forecast testing as currently the best method for ascertaining if models are capable to reasonably accounting for key physical governing processes—or not. Moreover, operational forecast models are of great interest to help on-site decision-making in projects entailing induced earthquakes. We previously introduced a standardized framework following the guidelines of the Collaboratory for the Study of Earthquake Predictability, the Induced Seismicity Test Bench, to test, validate, and rank induced seismicity models. In this study, we describe how to construct multicomponent ensemble models based on Bayesian weightings that deliver more accurate forecasts than individual models in the case of Basel 2006 and Soultz-sous-Forêts 2004 enhanced geothermal stimulation projects. For this, we examine five calibrated variants of two significantly different model groups: (1) Shapiro and Smoothed Seismicity based on the seismogenic index, simple modified Omori-law-type seismicity decay, and temporally weighted smoothed seismicity; (2) Hydraulics and Seismicity based on numerically modelled pore pressure evolution that triggers seismicity using the Mohr-Coulomb failure criterion. We also demonstrate how the individual and ensemble models would perform as part of an operational Adaptive Traffic Light System. Investigating seismicity forecasts based on a range of potential injection scenarios, we use forecast periods of different durations to compute the occurrence probabilities of seismic events M ≥ 3. We show that in the case of the Basel 2006 geothermal stimulation the models forecast hazardous levels

  12. 24-gauge ultrafine cryoprobe with diameter of 550 μm and its cooling performance.

    Science.gov (United States)

    Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

    2014-12-01

    This paper describes the development of a novel cryoprobe with the same size as a 24-gauge injection needle and the evaluation of its cooling performance. This ultrafine cryoprobe was designed to reduce the invasiveness and extend application areas of cryosurgery. The ultrafine cryoprobe has a double-tube structure and consists of two stainless steel microtubes. The outer diameter of the cryoprobe is 550 μm, and the inner tube has a 70-μm inner diameter to depressurize the high-pressure refrigerant. By solving the bioheat transfer equation and considering freezing phenomena, the relationship between the size of the frozen region and the heat transfer coefficient of the refrigerant flow in an ultrafine cryoprobe was derived analytically. The results showed that the size of the frozen region is strongly affected by the heat transfer coefficient. A high heat transfer coefficient such as that of phase change heat transfer is required to generate a frozen region of sufficient size. In the experiment, trifluoromethane (HFC-23) was used as the refrigerant, and the cooling effects of the gas and liquid phase states at the inlet were evaluated. When the ultrafine cryoprobe was cooled using a liquid refrigerant, the surface temperature was approximately -50°C, and the temperature distribution on the surface was uniform for a thermally insulated condition. However, for the case with vaporized refrigerant, the temperature distribution was not uniform. Therefore, it was concluded that the cooling mechanism using liquid refrigerant was suitable for ultrafine cryoprobes. Furthermore, to simulate cryosurgery, a cooling experiment using hydrogel was conducted. The results showed that the surface temperature of the ultrafine cryoprobe reached -35°C and formed a frozen region with a radius of 4 mm in 4 min. These results indicate that the ultrafine cryoprobe can be applied in actual cryosurgeries for small affected areas. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. DSMC multicomponent aerosol dynamics: Sampling algorithms and aerosol processes

    Science.gov (United States)

    Palaniswaamy, Geethpriya

    The post-accident nuclear reactor primary and containment environments can be characterized by high temperatures and pressures, and fission products and nuclear aerosols. These aerosols evolve via natural transport processes as well as under the influence of engineered safety features. These aerosols can be hazardous and may pose risk to the public if released into the environment. Computations of their evolution, movement and distribution involve the study of various processes such as coagulation, deposition, condensation, etc., and are influenced by factors such as particle shape, charge, radioactivity and spatial inhomogeneity. These many factors make the numerical study of nuclear aerosol evolution computationally very complicated. The focus of this research is on the use of the Direct Simulation Monte Carlo (DSMC) technique to elucidate the role of various phenomena that influence the nuclear aerosol evolution. In this research, several aerosol processes such as coagulation, deposition, condensation, and source reinforcement are explored for a multi-component, aerosol dynamics problem in a spatially homogeneous medium. Among the various sampling algorithms explored the Metropolis sampling algorithm was found to be effective and fast. Several test problems and test cases are simulated using the DSMC technique. The DSMC results obtained are verified against the analytical and sectional results for appropriate test problems. Results show that the assumption of a single mean density is not appropriate due to the complicated effect of component densities on the aerosol processes. The methods developed and the insights gained will also be helpful in future research on the challenges associated with the description of fission product and aerosol releases.

  14. Universal multi-component prevention programs for alcohol misuse in young people.

    Science.gov (United States)

    Foxcroft, David R; Tsertsvadze, Alexander

    2011-09-07

    Alcohol misuse in young people is a cause of concern for health services, policy makers, prevention workers, and criminal justice system, youth workers, teachers, and parents. To systematically review evidence on the effectiveness of universal multi-component prevention programs in preventing alcohol misuse in school-aged children up to 18 years of age. To update a part of a previously published Cochrane systematic review. Relevant evidence (up to 2002) was selected from the previous Cochrane review. Later studies, to July 2010, were identified from MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, Project CORK, and PsycINFO. Randomized trials evaluating universal multi-component prevention programs (intervention delivered in more than one setting) and reporting outcomes for alcohol use in students 18 years of age or younger were included. Two reviewers screened titles/abstracts and full text of identified records. Two reviewers extracted relevant data independently using an a priori defined extraction form. Risk of bias was assessed. 20 parallel-group trials were included. The reporting quality of trials was poor, only 25% and 5% of them reporting adequate method of randomisation and program allocation concealment, respectively. Incomplete data was adequately addressed in about half of the trials and this information was unclear for about 20% of the trials. Due to extensive heterogeneity across interventions, populations, and outcomes, the results were summarized only qualitatively.12 of the 20 trials showed some evidence of effectiveness compared to a control or other intervention group, with persistence of effects ranging from 3 months to 3 years. Of the remaining 8 trials, one trial reported significant effects using one-tailed tests and 7 trials reported no significant effects of the multi-component interventions for reducing alcohol misuse.Assessment of the additional benefit of multiple versus single component interventions was possible in 7

  15. Predicting liquid immiscibility in multicomponent nuclear waste glasses

    International Nuclear Information System (INIS)

    Peeler, D.K.; Hrma, P.R.

    1994-01-01

    Taylor's model for predicting amorphous phase separation in complex, multicomponent systems has been applied to high-level (simulated) radioactive waste glasses at the U.S. Department of Energy's Hanford site. Taylor's model is primarily based on additions of modifying cations to a Na 2 O-B 2 O 3 -SiO 2 (NBS) submixture of the multicomponent glass. The position of the submixture relative to the immiscibility dome defines the development probability of amorphous phase separation. Although prediction of amorphous phase separation in Hanford glasses (via experimental SEM/TEM analysis) is the primary thrust of this work; reported durability data is also provides limited insight into the composition/durability relationship. Using a modified model similar to Taylor's, the results indicate that immiscibility may be predicted for multicomponent waste glasses by the addition of Li 2 O to the open-quotes alkaliclose quotes corner of the NBS submixture

  16. Predicting liquid immiscibility in multicomponent nuclear waste glasses

    International Nuclear Information System (INIS)

    Peeler, D.K.; Hrma, P.R.

    1994-04-01

    Taylor's model for predicting amorphous phase separation in complex, multicomponent systems has been applied to high-level (simulated) radioactive waste glasses at the US Department of Energy's Hanford site. Taylor's model is primarily based on additions of modifying cations to a Na 2 O-B 2 O 3 -SiO 2 (NBS) submixture of the multicomponent glass. The position of the submixture relative to the miscibility dome defines the development probability of amorphous phase separation. Although prediction of amorphous phase separation in Hanford glasses (via experimental SEM/TEM analysis) is the primary thrust of this work; reported durability data is also provides limited insight into the composition/durability relationship. Using a modified model similar to Taylor's, the results indicate that immiscibility may be predicted for multicomponent waste glasses by the addition of Li 2 O to the ''alkali'' corner of the NBS submixture

  17. Mathematical Model for Multicomponent Adsorption Equilibria Using Only Pure Component Data

    DEFF Research Database (Denmark)

    Marcussen, Lis

    2000-01-01

    A mathematical model for nonideal adsorption equilibria in multicomponent mixtures is developed. It is applied with good results for pure substances and for prediction of strongly nonideal multicomponent equilibria using only pure component data. The model accounts for adsorbent-adsorbate and ads......A mathematical model for nonideal adsorption equilibria in multicomponent mixtures is developed. It is applied with good results for pure substances and for prediction of strongly nonideal multicomponent equilibria using only pure component data. The model accounts for adsorbent...

  18. Calculation and experimental investigation of multi-component ceramic systems

    International Nuclear Information System (INIS)

    Rother, M.

    1994-12-01

    This work shows a way to combine thermodynamic calculations and experiments in order to get useful information on the constitution of metal/non-metal systems. Many data from literature are critically evaluated and used as a basis for experiments and calculations. The following multi-component systems are treated: 1. Multi-component systems of 'ceramic' materials with partially metallic bonding (carbides, nitrides, oxides, borides, carbonitrides, borocarbides, oxinitrides of the 4-8th transition group metals) 2. multi-component systems of non-metallic materials with dominant covalent bonding (SiC, Si 3 N 4 , SiB 6 , BN, Al 4 C 3 , Be 2 C) 3. multi-component systems of non-metallic materials with dominant heteropolar bonding (Al 2 O 3 , TiO 2 , BeO, SiO 2 , ZrO 2 ). The interactions between 1. and 2., 2. and 3., 1. and 3. are also considered. The latest commercially available programmes for the calculation of thermodynamical equilibria and phase diagrams are evaluated and compared considering their facilities and limits. New phase diagrams are presented for many presently unknown multi-component systems; partly known systems are completed on the basis of selected thermodynamic data. The calculations are verified by experimental investigations (metallurgical and powder technology methods). Altogether 690 systems are evaluated, 126 are calculated for the first time and 52 systems are experimentally verified. New data for 60 ternary phases are elaborated by estimating the data limits for the Gibbs energy values. A synthesis of critical evaluation of literature, calculations and experiments leads to new important information about equilibria and reaction behaviour in multi-component systems. This information is necessary to develop new stable and metastable materials. (orig./MM) [de

  19. Deep Sequencing Transcriptome Analysis of Murine Wound Healing: Effects of a Multicomponent, Multitarget Natural Product Therapy-Tr14.

    Science.gov (United States)

    St Laurent, Georges; Seilheimer, Bernd; Tackett, Michael; Zhou, Jianhua; Shtokalo, Dmitry; Vyatkin, Yuri; Ri, Maxim; Toma, Ian; Jones, Dan; McCaffrey, Timothy A

    2017-01-01

    Wound healing involves an orchestrated response that engages multiple processes, such as hemostasis, cellular migration, extracellular matrix synthesis, and in particular, inflammation. Using a murine model of cutaneous wound repair, the transcriptome was mapped from 12 h to 8 days post-injury, and in response to a multicomponent, multi-target natural product, Tr14. Using single-molecule RNA sequencing (RNA-seq), there were clear temporal changes in known transcripts related to wound healing pathways, and additional novel transcripts of both coding and non-coding genes. Tr14 treatment modulated >100 transcripts related to key wound repair pathways, such as response to wounding, wound contraction, and cytokine response. The results provide the most precise and comprehensive characterization to date of the transcriptome's response to skin damage, repair, and multicomponent natural product therapy. By understanding the wound repair process, and the effects of natural products, it should be possible to intervene more effectively in diseases involving aberrant repair.

  20. Suppression of polymethyl methacrylate dust explosion by ultrafine water mist/additives.

    Science.gov (United States)

    Gan, Bo; Li, Bei; Jiang, Haipeng; Bi, Mingshu; Gao, Wei

    2018-06-05

    The suppressions of ultrafine water mists containing additives (NaCl and NaHCO 3 ) on 100 nm, 5 μm, and 30 μm polymethyl methacrylate (PMMA) dust explosions were experimentally studied in a dust-explosion apparatus. High-speed photography showed that maximum vertical positions and flame propagation velocities were significantly decreased by suppression with ultrafine water mist/additives. Flame propagation velocities in 100 nm, 5 μm, and 30 μm dust explosions suppressed by the ultrafine pure water mist were reduced by 48.2%, 27.7%, and 15.3%, respectively. Maximum temperatures and temperature rising rates measured by a fine thermocouple in nano- and micro-PMMA dust explosions were also significantly decreased. It was proved that the addition of NaCl and NaHCO 3 improved the suppression effects of the ultrafine pure water mist. The improvement of explosion suppression by an 8% NaHCO 3 mist was superior to that of a 16% NaCl mist. The suppression mechanisms of ultrafine water mist/additives are further discussed by analyzing the physical and chemical effects. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Bake hardening of ultra-fine grained low carbon steel produced by constrained groove pressing

    International Nuclear Information System (INIS)

    Alihosseini, H.; Dehghani, K.

    2012-01-01

    Highlights: ► BH of UFG low carbon steel sheets was studied. ► Three passes of CGP are used for producing of UFG sheets. ► Maximum BH was achieved to the UFG specimen pre-strained 8% by baking at 250 °C. - Abstract: In the present work, the bake hardening of ultra-fine grained low carbon steel was compared with that of its coarse-grain counterpart. The ultra-fine grained sheets were produced by applying three passes of constrained groove pressing resulting the grains of 260–270 nm. The microstructure of ultra-fine grain specimens were characterized using electron back-scatter diffraction technique. Then, the bake hardenability of ultra-fine grain and coarse-grain samples were compared by pre-straining to 4, 6 and 8% followed by baking at 150 °C and 250 °C for 20 min. The results show that in case of baking at 250 °C, there was an increase about 108%, 93%, and 72% in the bake hardening for 4%, 6% and 8% pre-strain, respectively. As for baking at 150 °C, these values were 170%, 168%, and 100%, respectively for 4%, 6% and 8% pre-strain. The maximum in bake hardenability (103 MPa) and final yield stress (563 MPa) were pertaining to the ultra-fine grain specimen pre-strained 8% followed by baking at 250 °C.

  2. MULTICOMPONENT SOLUTION FOR LOCAL ANAESTHESIA IN OPERATIONS ON EXTREMITIES

    Directory of Open Access Journals (Sweden)

    V.I. Sobolev

    2008-03-01

    Full Text Available The analysis of the results of local anaesthesia (LA in 89 patients aged 18 to 68 years with trauma and diseases of extremities has been carried out. The efficiency of perineural injected multicomponent solution of clonidine added to conventional mixture oflidocaine and phentanyl has been assessed. The multicomponent method has significantly prolonged the duration of local anaesthesia of 1% lidocaine solution providing reliable anaesthesia of plexus and peripheral nerves alongside the sufficient regional myoplegia and prolonged postoperative anesthetization. When there is no need of deep myoplegia Hallows to lower the concentration of lidocaine solution twofold, maintaining its efficiency, and to realize local anaesthesia of patients with high risk.

  3. Submicron confocal Raman imaging of holograms in multicomponent photopolymers

    Science.gov (United States)

    Kagan, C. R.; Harris, T. D.; Harris, A. L.; Schilling, M. L.

    1998-04-01

    We report submicron chemical imaging of optical holograms in multicomponent photopolymers using a confocal scanning Raman microscope. The microscope is sensitive to the submicron, ˜1% concentration variations of the polymeric components that form refractive index modulations (Δn) responsible for hologram diffraction. Concentration variations are established by both small molecule diffusion and polymer matrix swelling during hologram writing. Both density and composition variations contribute to Δn. These measurements demonstrate that submicron Raman microscopy is applicable to multicomponent organic, inorganic, and hybrid materials as a route to correlate materials chemistry/morphology with their physical properties.

  4. Multicomponent phase change microfibers prepared by temperature control multifluidic electrospinning.

    Science.gov (United States)

    Wang, Nü; Chen, Hongyan; Lin, Ling; Zhao, Yong; Cao, Xinyu; Song, Yanlin; Jiang, Lei

    2010-09-15

    Multicomponent phase change microfibers, which can storage and release thermal energy in a stepwise manner, are firstly prepared through a facile one-step multifluidic compound-jet electrospinning with temperature control. The multiresponsive effect benefits from a special multichannel tubular microstructure that could controllably encapsulate different phase change materials into the channels independently. Aside from the fabrication of multicomponent phase change microfibers, the melt multifluidic compound-jet electrospinning is promising for applications related to microencapsulation and multifunctional material fields. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Impact Toughness of Ultrafine-Grained Interstitial-Free Steel

    Science.gov (United States)

    Saray, Onur; Purcek, Gencaga; Karaman, Ibrahim; Maier, Hans J.

    2012-11-01

    Impact toughness of an ultrafine-grained (UFG) interstitial-free (IF) steel produced by equal-channel angular extrusion/pressing (ECAE/P) at room temperature was investigated using Charpy impact tests. The UFG IF steel shows an improved combination of strength and impact toughness compared with the corresponding coarse-grained (CG) one. The CG IF steel samples underwent a transition in fracture toughness values with decreasing temperature because of a sudden change in fracture mode from microvoid coalescence (ductile) to cleavage (brittle) fracture. Grain refinement down to the submicron (≈320 nm) levels increased the impact energies in the upper shelf and lower shelf regions, and it considerably decreased the ductile-to-brittle transition temperature (DBTT) from 233 K (-40 °C) for the CG steel to approximately 183 K (-90 °C) for the UFG steel. Also, the sudden drop in DBTT with a small transition range for the CG sample changed to a more gradual decrease in energy for the UFG sample. The improvement in toughness after UFG formation was attributed to the combined effects of grain refinement and delamination and/or separation in the heavily deformed microstructure. Although an obvious change from the ductile fracture by dimples to the brittle fracture by cleavage was recognized at 233 K (-40 °C) for the CG steel, no fully brittle fracture occurred even at 103 K (-170 °C) in the UFG steel.

  6. Exposure to inhalable, respirable, and ultrafine particles in welding fume.

    Science.gov (United States)

    Lehnert, Martin; Pesch, Beate; Lotz, Anne; Pelzer, Johannes; Kendzia, Benjamin; Gawrych, Katarzyna; Heinze, Evelyn; Van Gelder, Rainer; Punkenburg, Ewald; Weiss, Tobias; Mattenklott, Markus; Hahn, Jens-Uwe; Möhlmann, Carsten; Berges, Markus; Hartwig, Andrea; Brüning, Thomas

    2012-07-01

    This investigation aims to explore determinants of exposure to particle size-specific welding fume. Area sampling of ultrafine particles (UFP) was performed at 33 worksites in parallel with the collection of respirable particles. Personal sampling of respirable and inhalable particles was carried out in the breathing zone of 241 welders. Median mass concentrations were 2.48 mg m(-3) for inhalable and 1.29 mg m(-3) for respirable particles when excluding 26 users of powered air-purifying respirators (PAPRs). Mass concentrations were highest when flux-cored arc welding (FCAW) with gas was applied (median of inhalable particles: 11.6 mg m(-3)). Measurements of particles were frequently below the limit of detection (LOD), especially inside PAPRs or during tungsten inert gas welding (TIG). However, TIG generated a high number of small particles, including UFP. We imputed measurements welding fume. Concentrations were mainly predicted by the welding process and were significantly higher when local exhaust ventilation (LEV) was inefficient or when welding was performed in confined spaces. Substitution of high-emission techniques like FCAW, efficient LEV, and using PAPRs where applicable can reduce exposure to welding fume. However, harmonizing the different exposure metrics for UFP (as particle counts) and for the respirable or inhalable fraction of the welding fume (expressed as their mass) remains challenging.

  7. Room Temperature Dynamic Strain Aging in Ultrafine-Grained Titanium

    Science.gov (United States)

    Lopes, Felipe Perissé D.; Lu, Chia Hui; Zhao, Shiteng; Monteiro, Sergio N.; Meyers, Marc A.

    2015-10-01

    Dynamic strain aging (DSA) in coarse-grained (CG) titanium is usually observed at intermediate to high temperatures 473 K to 973 K (200 °C to 700 °C) and is characterized by serrations in the stress vs strain curves. In the present work, despite the absence of apparent serrations, ultrafine-grained titanium (UFG Ti) undergoes DSA at room temperature, exhibited through an abnormal increase in the elastic limit and negative strain rate sensitivity. This effect is observed at 293 K (20 °C) in the strain rate interval of 10-4 to 10-2 s-1, and at 203 K (-70 °C) and 373 K (100 °C) in a distinct strain rate range. Based on a calculated activation energy of 17.3 kJ/mol and microstructural observations by transmission electron microscopy, it is proposed that the dominant mechanism for DSA in UFG Ti involves interstitial solutes interacting with dislocations emitted from grain boundaries. The interstitials migrate from the grain boundaries along dislocation lines bowing out as they are emitted from the boundaries, a mechanism with a low calculated activation energy which is comparable with the experimental measurements. The dislocation velocities and interstitial diffusion along the dislocation cores are consistent.

  8. POTENTIAL PATHOPHYSIOLOGICAL MECHANISMS OF ULTRAFINE PARTICLE TOXIC EFFECTS IN HUMANS

    Directory of Open Access Journals (Sweden)

    JASMINA JOVIĆ-STOŠIĆ

    2008-03-01

    Full Text Available Epidemiological and clinical studies suggested the association of the particulate matter ambient air pollution and the increased morbidity and mortality, mainly from respiratory and cardiovascular diseases. The size of particles has great influence on their toxicity, because it determines the site in the respiratory tract where they deposit. The most well established theory explaining the mechanisms behind the increased toxicity of ultrafine particles (UFP, < 0.1 µm is that it has to do with the increased surface area and/or the combination with the increased number of particles. Biological effects of UFP are also determined by their shape and chemical composition, so it is not possible to estimate their toxicity in a general way. General hypothesis suggested that exposure to inhaled particles induces pulmonary alveolar inflammation as a basic pathophysiological event, triggering release of various proinflammatory cytokines. Chronic inflammation is a very important underlying mechanism in the genesis of atherosclerosis and cardiovascular diseases. UFP can freely move through the circulation, but their effects on the secondary organs are not known yet, so more studies on recognizing toxicological endpoints of UFP are needed. Determination of UFP toxicity and the estimation of their internal and biologically active dose are necessary for the evidence based conclusions connecting air pollution by UFP and human diseases.

  9. Magnetic anisotropy of ultrafine 316L stainless steel fibers

    Energy Technology Data Exchange (ETDEWEB)

    Shyr, Tien-Wei, E-mail: twshyr@fcu.edu.tw [Department of Fiber and Composite Materials, Feng Chia University, No. 100, Wenhwa Road, Seatwen, Taichung 40724, Taiwan, ROC (China); Huang, Shih-Ju [Department of Fiber and Composite Materials, Feng Chia University, No. 100, Wenhwa Road, Seatwen, Taichung 40724, Taiwan, ROC (China); Wur, Ching-Shuei [Department of Physics, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan, ROC (China)

    2016-12-01

    An as-received 316L stainless steel fiber with a diameter of 20 μm was drawn using a bundle drawing process at room temperature to form ultrafine stainless steel fibers with diameters of 12, 8, and 6 μm. The crystalline phases of the fibers were analyzed using the X-ray diffraction (XRD) profile fitting technique. The grain sizes of γ-austenite and α′-martensite were reduced to nanoscale sizes after the drawing process. XRD analysis and focused ion beam-scanning electron microscope observations showed that the newly formed α′-martensitic grains were closely arrayed in the drawing direction. The magnetic property was measured using a superconducting quantum interference device vibrating sample magnetometer. The magnetic anisotropy of the fibers was observed by applying a magnetic field parallel and perpendicular to the fiber axis. The results showed that the microstructure anisotropy including the shape anisotropy, magnetocrystalline anisotropy, and the orientation of the crystalline phases strongly contributed to the magnetic anisotropy. - Highlights: • The martensitic transformation of the 316L SS fiber occurred during the cold drawn. • The grain sizes of γ-austenite and α′-martensite were reduced to the nanoscale. • The newly formed martensitic grains were closely arrayed in the drawing direction. • The drawing process caused the magnetic easy axis to be aligned with the fiber axis. • The microstructure anisotropy strongly contributed to the magnetic anisotropy.

  10. Outdoor ultrafine particle concentrations in front of fast food restaurants.

    Science.gov (United States)

    Vert, Cristina; Meliefste, Kees; Hoek, Gerard

    2016-01-01

    Ultrafine particles (UFPs) have been associated with negative effects on human health. Emissions from motor vehicles are the principal source of UFPs in urban air. A study in Vancouver suggested that UFP concentrations were related to density of fast food restaurants near the monitoring sites. A previous monitoring campaign could not separate the contribution of restaurants from road traffic. The main goal of this study has been the quantification of fast food restaurants' contribution to outdoor UFP concentrations. A portable particle number counter (DiscMini) has been used to carry out mobile monitoring in a largely pedestrianized area in the city center of Utrecht. A fixed route passing 17 fast food restaurants was followed on 8 days. UFP concentrations in front of the restaurants were 1.61 times higher than in a nearby square without any local sources used as control area and 1.22 times higher compared with all measurements conducted in between the restaurants. Adjustment for other sources such as passing mopeds, smokers or candles did not explain the increase. In conclusion, fast food restaurants result in significant increases in outdoor UFP concentrations in front of the restaurant.

  11. Ultrafine particle air pollution inside diesel-propelled passenger trains.

    Science.gov (United States)

    Abramesko, Victoria; Tartakovsky, Leonid

    2017-07-01

    Locomotives with diesel engines are used worldwide and are an important source of air pollution. Pollutant emissions by locomotive engines affect the air quality inside passenger trains. This study is aimed at investigating ultrafine particle (UFP) air pollution inside passenger trains and providing a basis for assessing passenger exposure to this pollutant. The concentrations of UFPs inside the carriages of push-pull trains are dramatically higher when the train operates in pull mode. This clearly shows that locomotive engine emissions are a dominant factor in train passengers' exposure to UFPs. The highest levels of UFP air pollution are observed inside the carriages of pull trains close to the locomotive. In push mode, the UFP number concentrations were lower by factors of 2.6-43 (depending on the carriage type) compared to pull mode. The UFP concentrations are substantially lower in diesel multiple-unit trains than in trains operating in pull mode. A significant influence of the train movement regime on the UFP NC inside a carriage is observed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Multicomponent fluid flow analysis using a new set of conservation equations

    International Nuclear Information System (INIS)

    Kamali, Reza; Emdad, Homayoon; Alishahi, Mohammad M

    2008-01-01

    In this work hydrodynamics of multicomponent ideal gas mixtures have been studied. Starting from the kinetic equations, the Eulerian approach is used to derive a new set of conservation equations for the multicomponent system where each component may have different velocity and kinetic temperature. The equations are based on the Grad's method of moment derived from the kinetic model in a relaxation time approximation (RTA). Based on this model which contains separate equation sets for each component of the system, a computer code has been developed for numerical computation of compressible flows of binary gas mixture in generalized curvilinear boundary conforming coordinates. Since these equations are similar to the Navier-Stokes equations for the single fluid systems, the same numerical methods are applied to these new equations. The Roe's numerical scheme is used to discretize the convective terms of governing fluid flow equations. The prepared algorithm and the computer code are capable of computing and presenting flow fields of each component of the system separately as well as the average flow field of the multicomponent gas system as a whole. Comparison of the present code results with those of a more common algorithm based on the mixture theory in a supersonic converging-diverging nozzle provides the validation of the present formulation. Afterwards, a more involved nozzle cooling problem with a binary ideal gas (helium-xenon) is chosen to compare the present results with those of the ordinary mixture theory. The present model provides the details of the flow fields of each component separately which is not available otherwise. It is also shown that the separate fluids treatment, such as the present study, is crucial when considering time scales on the order of (or shorter than) the intercollisions relaxation times.

  13. Inhalation of ultrafine carbon particles alters heart rate and heart rate variability in people with type 2 diabetes.

    Science.gov (United States)

    Vora, Rathin; Zareba, Wojciech; Utell, Mark J; Pietropaoli, Anthony P; Chalupa, David; Little, Erika L; Oakes, David; Bausch, Jan; Wiltshire, Jelani; Frampton, Mark W

    2014-07-16

    Diabetes may confer an increased risk for the cardiovascular health effects of particulate air pollution, but few human clinical studies of air pollution have included people with diabetes. Ultrafine particles (UFP, ≤100 nm in diameter) have been hypothesized to be an important component of particulate air pollution with regard to cardiovascular health effects. 17 never-smoker subjects 30-60 years of age, with stable type 2 diabetes but otherwise healthy, inhaled either filtered air (0-10 particles/cm3) or elemental carbon UFP (~107 particles/cm3, ~50 ug/m3, count median diameter 32 nm) by mouthpiece, for 2 hours at rest, in a double-blind, randomized, crossover study design. A digital 12-lead electrocardiogram (ECG) was recorded continuously for 48 hours, beginning 1 hour prior to exposure. Analysis of 5-minute segments of the ECG during quiet rest showed reduced high-frequency heart rate variability with UFP relative to air exposure (p = 0.014), paralleled by non-significant reductions in time-domain heart rate variability parameters. In the analysis of longer durations of the ECG, we found that UFP exposure increased the heart rate relative to air exposure. During the 21- to 45-hour interval after exposure, the average heart rate increased approximately 8 beats per minute with UFP, compared to 5 beats per minute with air (p = 0.045). There were no UFP effects on cardiac rhythm or repolarization. Inhalation of elemental carbon ultrafine particles alters heart rate and heart rate variability in people with type 2 diabetes. Our findings suggest that effects may occur and persist hours after a single 2-hour exposure.

  14. Multicomponent Body and Surface Wave Seismic Analysis using an Urban Land Streamer System: An Integrative Earthquake Hazards Assessment Approach

    Science.gov (United States)

    Gribler, G.; Liberty, L. M.

    2014-12-01

    We present earthquake site response results from a 48-channel multicomponent seismic land streamer and large weight drop system. We acquired data along a grid of city streets in western Idaho at a rate of a few km per day where we derived shear wave velocity profiles to a depth of 40-50 m by incorporating vertical and radial geophone signals to capture the complete elliptical Rayleigh wave motion. We also obtained robust p-wave reflection and refraction results by capturing the returned signals that arrive at non-vertical incidence angles that result from the high-velocity road surface layer. By integrating the derived shear wave velocity profiles with p-wave reflection results, we include depositional and tectonic boundaries from the upper few hundred meters into our analysis to help assess whether ground motions may be amplified by shallow bedrock. By including p-wave refraction information into the analysis, we can identify zones of high liquefaction potential by comparing shear wave and p-wave velocity (Vp/Vs) measurements relative to refraction-derived water table depths. The utilization of multicomponent land streamer data improves signal-noise levels over single component data with no additional field effort. The added multicomponent data processing step can be as simple as calculating the magnitude of the vector for surface wave and refraction arrivals or rotating the reflected signals to the maximum emergence angle based on near surface p-wave velocity information. We show example data from a number of Idaho communities where historical earthquakes have been recorded. We also present numerical models and systematic field tests that show the effects of a high velocity road surface layer in surface and body wave measurements. We conclude that multicomponent seismic information derived from seismic land streamers can provide a significant improvement in earthquake hazard assessment over a standard single component approach with only a small addition in

  15. Multi-component testing using HZ-PAN and AgZ-PAN Sorbents for OSPREY Model validation

    Energy Technology Data Exchange (ETDEWEB)

    Garn, Troy G. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Greenhalgh, Mitchell [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lyon, Kevin L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Law, Jack D. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-04-01

    In efforts to further develop the capability of the Off-gas SeParation and RecoverY (OSPREY) model, multi-component tests were completed using both HZ-PAN and AgZ-PAN sorbents. The primary purpose of this effort was to obtain multi-component xenon and krypton capacities for comparison to future OSPREY predicted multi-component capacities using previously acquired Langmuir equilibrium parameters determined from single component isotherms. Experimental capacities were determined for each sorbent using two feed gas compositions of 1000 ppmv xenon and 150 ppmv krypton in either a helium or air balance. Test temperatures were consistently held at 220 K and the gas flowrate was 50 sccm. Capacities were calculated from breakthrough curves using TableCurve® 2D software by Jandel Scientific. The HZ-PAN sorbent was tested in the custom designed cryostat while the AgZ-PAN was tested in a newly installed cooling apparatus. Previous modeling validation efforts indicated the OSPREY model can be used to effectively predict single component xenon and krypton capacities for both engineered form sorbents. Results indicated good agreement with the experimental and predicted capacity values for both krypton and xenon on the sorbents. Overall, the model predicted slightly elevated capacities for both gases which can be partially attributed to the estimation of the parameters and the uncertainty associated with the experimental measurements. Currently, OSPREY is configured such that one species adsorbs and one does not (i.e. krypton in helium). Modification of OSPREY code is currently being performed to incorporate multiple adsorbing species and non-ideal interactions of gas phase species with the sorbent and adsorbed phases. Once these modifications are complete, the sorbent capacities determined in the present work will be used to validate OSPREY multicomponent adsorption predictions.

  16. Effect of ultrafine grain on tensile behaviour and corrosion resistance of the duplex stainless steel.

    Science.gov (United States)

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Limin, Dong

    2016-05-01

    The ultrafine grained 2205 duplex stainless steel was obtained by cold rolling and annealing. The tensile properties were investigated at room temperature. Comparing with coarse grained stainless steel, ultrafine grained sample showed higher strength and plasticity. In addition, grain size changed deformation orientation. The strain induced α'-martensite was observed in coarse grained 2205 duplex stainless steel with large strain. However, the grain refinement inhibited the transformation of α'-martensite;nevertheless, more deformation twins improved the strength and plasticity of ultrafine grained 2205 duplex stainless steel. In addition, the grain refinement improved corrosion resistance of the 2205 duplex stainless steel in sodium chloride solution. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Seasonal variation and volatility of ultra-fine particles in coastal Antarctic troposphere

    Directory of Open Access Journals (Sweden)

    Keiichiro Hara

    2010-12-01

    Full Text Available The Size distribution and volatility of ultrafine aerosol particles were measured at Syowa Station during the 46-47 Japanese Antarctic Research Expeditions. During the summer, most of the ultrafine particles were volatile particles, which were composed of H_2SO_4, CH_3SO_3H and sulfates bi-sulfates. The abundance of non-volatile particles was ~ 20% during the summer, increasing to>90% in winter-spring. Non-volatile particles in winter were dominantly sea-salt particles. Some ultrafine sea-salt particles might be released from sea-ice. When air mass was transported from the free troposphere over the Antarctic continent, the abundance of non-volatile particles dropped to<30% even in winter.

  18. Preservation of amorphous ultrafine material: A proposed proxy for slip during recent earthquakes on active faults.

    Science.gov (United States)

    Hirono, Tetsuro; Asayama, Satoru; Kaneki, Shunya; Ito, Akihiro

    2016-11-09

    The criteria for designating an "Active Fault" not only are important for understanding regional tectonics, but also are a paramount issue for assessing the earthquake risk of faults that are near important structures such as nuclear power plants. Here we propose a proxy, based on the preservation of amorphous ultrafine particles, to assess fault activity within the last millennium. X-ray diffraction data and electron microscope observations of samples from an active fault demonstrated the preservation of large amounts of amorphous ultrafine particles in two slip zones that last ruptured in 1596 and 1999, respectively. A chemical kinetic evaluation of the dissolution process indicated that such particles could survive for centuries, which is consistent with the observations. Thus, preservation of amorphous ultrafine particles in a fault may be valuable for assessing the fault's latest activity, aiding efforts to evaluate faults that may damage critical facilities in tectonically active zones.

  19. Multicomponent mixed dopant optimization for rapid screening of polycyclic aromatic hydrocarbons using ultra high performance liquid chromatography coupled to atmospheric pressure photoionization high-resolution mass spectrometry

    KAUST Repository

    Sioud, Salim

    2012-05-04

    RATIONALE To enhance the ionization efficiencies in atmospheric pressure photoionization mass spectrometry a dopant with favorable ionization energy such as chlorobenzene is typically used. These dopants are typically toxic and difficult to mix with water-soluble organic solvents. In order to achieve a more efficient and less toxic dopant, a multicomponent mixed dopant was explored. METHODS A multicomponent mixed dopant for non-targeted rapid screening of polycyclic aromatic hydrocarbons (PAHs) was developed and optimized using ultra high performance liquid chromatography (UPLC) coupled to atmospheric pressure photoionization high-resolution mass spectrometry. Various single and multicomponent mixed dopants consisting of ethanol, chlorobenzene, bromobenzene, anisole and toluene were evaluated. RESULTS Fourteen out of eighteen PAHs were successfully separated and detected at low pg/μL levels within 5 min with high mass accuracy ≤4 ppm. The optimal mixed multicomponent dopant consisted of ethanol/chlorobenzene/bromobenzene/anisole (98.975:0.1:0.9:0.025, v/v %) and it improved the limit of detection (LOD) by 2- to 10-fold for the tested PAHs compared to those obtained with pure chlorobenzene. CONCLUSIONS A novel multicomponent dopant that contains 99% ethanol and 1% mixture of chlorobenzene, bromobenzene and anisole was found to be an effective dopant mixture to ionize PAHs. The developed UPLC multicomponent dopant assisted atmospheric pressure photoionization high-resolution mass spectrometry offered a rapid non targeted screening method for detecting the PAHs at low pg/;μL levels within a 5 min run time with high mass accuracy a;circ4 ppm. Copyright © 2012 John Wiley & Sons, Ltd.

  20. Effect of Ultrafine Pulverization of Senecio Scandens on Growth, Immune System and Faecal Microorganisms in Piglets

    Directory of Open Access Journals (Sweden)

    J Yue1, CQ Lu1, HY Lin1, XN Wang, JQ Zheng1, JJ Chen1* and R Gooneratne2*

    2016-11-01

    Full Text Available There is increased interest in using naturally occurring compounds subjected to new technologies for enhancing pig nutrition to replace antibiotic usage in swine production. The effects of ultrafine pulverization on the size distribution, morphology of Senecio scandens Buch.-Ham., and the growth performance, serum immunity parameters and faecal microorganisms of piglets fed this powder were investigated. The size distribution and morphology of S. scandens were characterized by using a laser diffraction analyser and scanning electron microscopy respectively. Ninety Duroc×Landrace×Yorkshire piglets (average body weight of 10.43kg were randomly assigned to six treatments with three pens of five pigs per treatment. Group 1 (Control piglets were fed the basal diet only. Groups 2 to 5 were fed with the basal diet supplemented with ultrafine powder (median diameter [d0.5] of 8.89μm of S. scandens at 0.3, 0.6, 0.9, and 1.2% of the basal diet, respectively, for 30 days. For group 6, 1.2% of ordinary S. scandens powder (d0.5=88.59μm was added to the basal diet. Both S. scandens ordinary and ultrafine powder increased piglet body weight and reduced the feed to gain ratio, but the performance of piglets fed the ultrafine powder was better. In groups 4 to 6, the number of Escherechia coli in faeces and the diarrhoeal incidence were significantly lower (P<0.05 and the serum IgA, IgG, IgM contents significantly higher (P<0.05. Feeding S. scandens ultrafine powder in the diet improved piglet performance and the diet supplemented with 0.9% of the ultrafine powder was the most effective.

  1. Personal exposure to ultrafine particles from PVC welding and concrete work during tunnel rehabilitation.

    Science.gov (United States)

    Jørgensen, Rikke Bramming; Buhagen, Morten; Føreland, Solveig

    2016-07-01

    To investigate the exposure to number concentration of ultrafine particles and the size distribution in the breathing zone of workers during rehabilitation of a subsea tunnel. Personal exposure was measured using a TSI 3091 Fast Mobility Particle Sizer (FMPS), measuring the number concentration of submicrometre particles (including ultrafine particles) and the particle size distribution in the size range 5.6-560 nm. The measurements were performed in the breathing zone of the operators by the use of a conductive silicone tubing. Working tasks studied were operation of the slipforming machine, operations related to finishing the verge, and welding the PVC membrane. In addition, background levels were measured. Arithmetic mean values of ultrafine particles were in the range 6.26×10(5)-3.34×10(6). Vertical PVC welding gave the highest exposure. Horizontal welding was the work task with the highest maximum peak exposure, 8.1×10(7) particles/cm(3). Background concentrations of 4.0×10(4)-3.1×10(5) were found in the tunnel. The mobility diameter at peak particle concentration varied between 10.8 nm during horizontal PVC welding and during breaks and 60.4 nm while finishing the verge. PVC welding in a vertical position resulted in very high exposure of the worker to ultrafine particles compared to other types of work tasks. In evaluations of worker exposure to ultrafine particles, it seems important to distinguish between personal samples taken in the breathing zone of the worker and more stationary work area measurements. There is a need for a portable particle-sizing instrument for measurements of ultrafine particles in working environments. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  2. Multicomponent Training of Teachers of Students with Severe Disabilities

    Science.gov (United States)

    Brown, Phillip; Stephenson, Jennifer; Carter, Mark

    2014-01-01

    Over the last decade, the obligation of general and special educators to utilize evidence-based instructional practices has become more prominent. Research increasingly suggests the failure of didactic teacher training alone to ensure implementation with fidelity of these practices by teachers in their classrooms. Multicomponent training (MCT)…

  3. Diffusion of elements and vacancies in multi-component systems

    Czech Academy of Sciences Publication Activity Database

    Fischer, F. D.; Svoboda, Jiří

    2014-01-01

    Roč. 60, MAR (2014), s. 338-367 ISSN 0079-6425 Institutional support: RVO:68081723 Keywords : multi-component diffusion * vacancy activity * manning theory * stress-driven diffusion Subject RIV: BJ - Thermodynamics Impact factor: 27.417, year: 2014

  4. Gibbs ensemble Monte Carlo simulations of multicomponent natural gas mixtures

    NARCIS (Netherlands)

    Ramdin, M.; Jamali, S.H.; Becker, T.M.; Vlugt, T.J.H.

    2018-01-01

    Vapour–liquid equilibrium (VLE) and volumetric data of multicomponent mixtures are extremely important for natural gas production and processing, but it is time consuming and challenging to experimentally obtain these properties. An alternative tool is provided by means of molecular simulation.

  5. Drying of liquid food droplets : enzyme inactivation and multicomponent diffusion

    NARCIS (Netherlands)

    Meerdink, G.

    1993-01-01

    In this thesis the drying of liquid food droplets is studied from three different points of view: drying kinetics, enzyme inactivation and multicomponent diffusion. Mathematical models are developed and validated experimentally.

    Drying experiments are performed with suspended

  6. Propagation of waves in a multicomponent plasma having charged ...

    Indian Academy of Sciences (India)

    Propagation of waves in a multicomponent plasma having charged dust particles has been investigated by various authors in recent times as the presence of charged dust grains give rise to a new kind of modes called dust modes and it has wide applications in magneto- sphere and space plasma [1–3]. In fact, Rao et al [4] ...

  7. Multicomponent Adsorption Model for Polar and Associating Mixtures

    DEFF Research Database (Denmark)

    Nesterov, Igor; Shapiro, Alexander; Kontogeorgis, Georgios M.

    2015-01-01

    The multicomponent potential adsorption theory (MPTA) is revisited in this work for polar and associating systems. MPTA is used in combination with the CPA equation of state. Previous Studies have shown that both MPTA and other theories present difficulties for complex systems. Some of these prob...

  8. Nucleation and growth of a multicomponent metallic glass

    Indian Academy of Sciences (India)

    Unknown

    were procured from the Allied Corporation. The kinetics of crystallization of this multicomponent glassy ... The purpose of present study is to apply DSC to ascer- tain the mechanism of crystallization and separate the ... were procured from Allied Corporation, USA. They were in the form of continuous ribbon (2⋅5 cm wide ...

  9. Spinodal decomposition in multicomponent fluid mixtures: A molecular dynamics study

    DEFF Research Database (Denmark)

    Laradji, Mohamed; Mouritsen, Ole G.; Toxvaerd, Søren

    1996-01-01

    We have investigated the effect of the number p of components on the dynamics of phase separation in two-dimensional symmetric multicomponent fluids. In contrast to concentrated two-dimensional binary fluids, where the growth dynamics is controlled by the coupling of the velocity held to the order...

  10. Dynamics of solitons in multicomponent long wave–short wave ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, we study the formation of solitons, their propagation and collision behaviour in an integrable multicomponent (2+1)-dimensional long wave–short wave resonance interaction (M-LSRI) system. First, we briefly revisit the earlier results on the dynamics of bright solitons and demonstrate the fascinating ...

  11. THE THERMAL CHARACTERIZATION OF MULTICOMPONENT SYSTEMS BY ENTHALPY RELAXATION

    NARCIS (Netherlands)

    TENBRINKE, G; OUDHUIS, L; ELLIS, TS

    1994-01-01

    The phenomenon of enthalpy relaxation of amorphous glassy polymers has been developed into an analytical tool which can be applied to elucidate phase behavior and morphologically related phenomena of multi-component systems. We have both reviewed the experimental details concerning its application,

  12. Adsorption of a multicomponent rhamnolipid surfactant to soil

    NARCIS (Netherlands)

    Noordman, Wouter H.; Brusseau, Mark L.; Janssen, Dick B.

    2000-01-01

    The adsorption of rhamnolipid, a multicomponent biosurfactant with potential application in soil remediation, to two sandy soils was investigated using batch and column studies. The surfactant mixture contained six anionic components differing in lipid chain length and number of rhamnose moieties.

  13. Kelvin Equation for a Non-Ideal Multicomponent Mixture

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1997-01-01

    The Kelvin equation is generalized by application to a case of a multicomponent non-ideal mixture. Such a generalization is necessary in order to describe the two-phase equilibrium in a capillary medium with respect to both normal and retrograde condensation. The equation obtained is applied...

  14. Rogue waves in the multicomponent Mel'nikov system and ...

    Indian Academy of Sciences (India)

    Baonan Sun

    2018-01-10

    Jan 10, 2018 ... Homoclinic and rogue wave solutions have been obtained by employing the. Hirota's bilinear method [66,67]. The goal of the present paper is to derive gen- eral rational solutions including rogue waves to the multicomponent Mel'nikov system and the multicom- ponent Schrödinger–Boussinesq equation.

  15. Multicomponent Fluids of Hard Spheres Near a Wall

    Czech Academy of Sciences Publication Activity Database

    Malijevský, Alexandr; Yuste, S.B.; Santos, A.; de Haro, M.L.

    2007-01-01

    Roč. 75, č. 6 (2007), 061201-1 ISSN 1539-3755 Institutional research plan: CEZ:AV0Z40720504 Keywords : density functional theory * monte carlo simulation * multicomponent fluid Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.483, year: 2007

  16. Isocyanide-mediated multicomponent synthesis of C-oximinoamidines.

    Science.gov (United States)

    Mercalli, Valentina; Meneghetti, Fiorella; Tron, Gian Cesare

    2013-11-15

    By capitalizing on the different reactivity of nitrile N-oxides with isocyanides and amine, α-oximinoamidines, a so far elusive class of compounds, have been synthesized in a straightforward way by reacting isocyanides, syn-chlorooximes, and amines in a multicomponent fashion.

  17. Early Reading Intervention by Means of a Multicomponent Reading Game

    Science.gov (United States)

    van de Ven, M.; de Leeuw, L.; van Weerdenburg, M.; Steenbeek-Planting, E. G.

    2017-01-01

    This study examined the effects of an intervention with a multicomponent reading game on the development of reading skills in 60 Dutch primary school children with special educational needs. The game contains evidence-based reading exercises and is based on principles of applied gaming. Using a multiple baseline approach, we tested children's…

  18. Immiscible multicomponent lattice Boltzmann model for fluids with ...

    Indian Academy of Sciences (India)

    Abstract. An immiscible multicomponent lattice Boltzmann model is developed for fluids with high relaxation time ratios, which is based on the model proposed by Shan and Chen (SC). In the SC model, an interaction potential between particles is incorporated into the discrete lattice. Boltzmann equation through the ...

  19. Enol esters: versatile substrates for Mannich-type multicomponent reactions.

    Science.gov (United States)

    Isambert, Nicolas; Cruz, Montse; Arévalo, María José; Gómez, Elena; Lavilla, Rodolfo

    2007-10-11

    The interaction of cyclic enol esters with diversely substituted anilines and ethyl glyoxalate yields, under Sc(OTf)3 catalysis, disubstituted N-aryl lactams in a multicomponent reaction. The protocol allows access to the trans stereoisomers after an epimerization of the initial mixture in which the cis isomers predominate. Vinyl acetate yields quinoline derivatives, whereas isopropenyl acetate leads to the corresponding Mannich adducts.

  20. Multicomponent Droplet Evaporation on Chemical Micro-Patterned Surfaces

    Science.gov (United States)

    He, Minghao; Liao, Dong; Qiu, Huihe

    2017-01-01

    The evaporation and dynamics of a multicomponent droplet on a heated chemical patterned surface were presented. Comparing to the evaporation process of a multicomponent droplet on a homogenous surface, it is found that the chemical patterned surface can not only enhance evaporation by elongating the contact line, but also change the evaporation process from three regimes for the homogenous surface including constant contact line (CCL) regime, constant contact angle (CCA) regime and mix mode (MM) to two regimes, i.e. constant contact line (CCL) and moving contact line (MCL) regimes. The mechanism of contact line stepwise movement in MCL regimes in the microscopic range is investigated in detail. In addition, an improved local force model on the contact line was employed for analyzing the critical receding contact angles on homogenous and patterned surfaces. The analysis results agree well for both surfaces, and confirm that the transition from CCL to MCL regimes indicated droplet composition changes from multicomponent to monocomponent, providing an important metric to predict and control the dynamic behavior and composition of a multicomponent droplet using a patterned surface. PMID:28157229

  1. Processing, application and characterization of ultrafine and nanometric materials in energetic compositions

    Science.gov (United States)

    van der Heijden, Antoine

    2005-07-01

    The energetic materials research at TNO Defence, Security and Safety, The Netherlands is focusing at the development and characterization of explosives (insensitive munitions), gun/rocket propellants and pyrotechnic compositions and their ingredients. The application of reactive, ultrafine and nanometric materials in these compositions has gained increased interest over the past few years. Current research topics focus on the processing, application and characterization of (1) ultrafine energetic crystals and composite nano-clusters in plastic bonded explosives, (2) metastable intermolecular composites (MICs) and (3) self-propagating high-temperature synthesis (SHS). In this paper several of these topics will be highlighted in more detail.

  2. Processing, Application and Characterization of (Ultra)fine and Nanometric Materials in Energetic Compositions

    Science.gov (United States)

    van der Heijden, A. E. D. M.; Bouma, R. H. B.; Carton, E. P.; Martinez Pacheco, M.; Meuken, B.; Webb, R.; Zevenbergen, J. F.

    2006-07-01

    The energetic materials research at TNO Defence, Security and Safety, The Netherlands is focusing at the development and characterization of explosives (insensitive munitions), gun/rocket propellants and pyrotechnic compositions and their ingredients. The application of reactive, (ultra)fine and nanometric materials in these compositions has gained increased interest over the past few years. Current research topics focus on the processing, application and characterization of (1) (ultra)fine energetic crystals and composite nano-clusters in plastic bonded explosives, (2) metastable intermolecular composites (MICs) and (3) self-propagating high-temperature synthesis (SHS). In this paper these topics will be highlighted in more detail.

  3. Multi-Component Molecular-Level Body Composition Reference Methods: Evolving Concepts and Future Directions

    Science.gov (United States)

    Heymsfield, Steven B.; Ebbeling, Cara B.; Zheng, Jolene; Pietrobelli, Angelo; Strauss, Boyd J.; Silva, Analiza M.; Ludwig, David S.

    2015-01-01

    Excess adiposity is the main phenotypic feature that defines human obesity and that plays a pathophysiological role in most chronic diseases. Measuring the amount of fat mass present is thus a central aspect of studying obesity at the individual and population levels. Nevertheless, a consensus is lacking among investigators on a single accepted “reference” approach for quantifying fat mass in vivo. While the research community generally relies on the multicomponent body-volume class of “reference” models for quantifying fat mass, no definable guide discerns among different applied equations for partitioning the four (fat, water, protein, and mineral mass) or more quantified components, standardizes “adjustment” or measurement system approaches for model-required labeled water dilution volumes and bone mineral mass estimates, or firmly establishes the body temperature at which model physical properties are assumed. The resulting differing reference strategies for quantifying body composition in vivo leads to small but under some circumstances important differences in the amount of measured body fat. Recent technological advances highlight opportunities to expand model applications to new subject groups and measured components such as total body protein. The current report reviews the historical evolution of multicomponent body volume-based methods in the context of prevailing uncertainties and future potential. PMID:25645009

  4. Vector dark-antidark solitary waves in multicomponent Bose-Einstein condensates

    Science.gov (United States)

    Danaila, I.; Khamehchi, M. A.; Gokhroo, V.; Engels, P.; Kevrekidis, P. G.

    2016-11-01

    Multicomponent Bose-Einstein condensates exhibit an intriguing variety of nonlinear structures. In recent theoretical work [C. Qu, L. P. Pitaevskii, and S. Stringari, Phys. Rev. Lett. 116, 160402 (2016), 10.1103/PhysRevLett.116.160402], the notion of magnetic solitons has been introduced. Here we examine a variant of this concept in the form of vector dark-antidark solitary waves in multicomponent Bose-Einstein condensates (BECs). We first provide concrete experimental evidence for such states in an atomic BEC and subsequently illustrate the broader concept of these states, which are based on the interplay between miscibility and intercomponent repulsion. Armed with this more general conceptual framework, we expand the notion of such states to higher dimensions presenting the possibility of both vortex-antidark states and ring-antidark-ring (dark soliton) states. We perform numerical continuation studies, investigate the existence of these states, and examine their stability using the method of Bogoliubov-de Gennes analysis. Dark-antidark and vortex-antidark states are found to be stable for broad parametric regimes. In the case of ring dark solitons, where the single-component ring state is known to be unstable, the vector entity appears to bear a progressively more and more stabilizing role as the intercomponent coupling is increased.

  5. Decoupling multimode vibrational relaxations in multi-component gas mixtures: Analysis of sound relaxational absorption spectra

    International Nuclear Information System (INIS)

    Zhang Ke-Sheng; Wang Shu; Zhu Ming; Ding Yi; Hu Yi

    2013-01-01

    Decoupling the complicated vibrational—vibrational (V—V) coupling of a multimode vibrational relaxation remains a challenge for analyzing the sound relaxational absorption in multi-component gas mixtures. In our previous work [Acta Phys. Sin. 61 174301 (2012)], an analytical model to predict the sound absorption from vibrational relaxation in a gas medium is proposed. In this paper, we develop the model to decouple the V—V coupled energy to each vibrational—translational deexcitation path, and analyze how the multimode relaxations form the peaks of sound absorption spectra in gas mixtures. We prove that a multimode relaxation is the sum of its decoupled single-relaxation processes, and only the decoupled process with a significant isochoric-molar-heat can be observed as an absorption peak. The decoupling model clarifies the essential processes behind the peaks in spectra arising from the multimode relaxations in multi-component gas mixtures. The simulation validates the proposed decoupling model. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  6. Pharmacokinetic Analysis of an Oral Multicomponent Joint Dietary Supplement (Phycox®) in Dogs.

    Science.gov (United States)

    Martinez, Stephanie E; Lillico, Ryan; Lakowski, Ted M; Martinez, Steven A; Davies, Neal M

    2017-08-18

    Despite the lack of safety, efficacy and pharmacokinetic (PK) studies, multicomponent dietary supplements (nutraceuticals) have become increasingly popular as primary or adjunct therapies for clinical osteoarthritis in veterinary medicine. Phycox ® is a line of multicomponent joint support supplements marketed for joint health in dogs and horses. Many of the active constituents are recognized anti-inflammatory and antioxidant agents. Due to a lack of PK studies in the literature for the product, a pilot PK study of select constituents in Phycox ® was performed in healthy dogs. Two novel methods of analysis were developed and validated for quantification of glucosamine and select polyphenols using liquid chromatography-tandem mass spectrometry. After a single oral (PO) administrated dose of Phycox ® , a series of blood samples from dogs were collected for 24 h post-dose and analyzed for concentrations of glucosamine HCl, hesperetin, resveratrol and naringenin. Non-compartmental PK analyses were carried out. Glucosamine was detected up to 8 h post-dose with a T max of 2 h and C max of 9.69 μg/mL. The polyphenols were not found at detectable concentrations in serum samples. Co-administration of glucosamine in the Phycox ® formulation may enhance the absorption of glucosamine as determined by comparison of glucosamine PK data in the literature.

  7. Ultrafine-grained Aluminm and Boron Carbide Metal Matrix Composites

    Science.gov (United States)

    Vogt, Rustin

    Cryomilling is a processing technique used to generate homogenously distributed boron carbide (B4C) particulate reinforcement within an ultrafine-grained aluminum matrix. The motivation behind characterizing a composite consisting of cryomilled aluminum B4C metal matrix composite is to design and develop a high-strength, lightweight aluminum composite for structural and high strain rate applications. Cryomilled Al 5083 and B4C powders were synthesized into bulk composite by various thermomechanical processing methods to form plate and extruded geometries. The effects of processing method on microstructure and mechanical behavior for the final consolidated composite were investigated. Cryomilling for extended periods of time in liquid nitrogen has shown to increase strength and thermal stability. The effects associated with cryomilling with stearic acid additions (as a process-control agent) on the degassing behavior of Al powders is investigated and results show that the liberation of compounds associated with stearic acid were suppressed in cryomilled Al powders. The effect of thermal expansion mismatch strain on strengthening due to geometrically necessary dislocations resulting from quenching is investigated and found not to occur in bulk cryomilled Al 5083 and B 4C composites. Previous cryomilled Al 5083 and B4C composites have exhibited ultrahigh strength associated with considerable strain-to-failure (>14 pct.) at high strain rates (>103/s) during mechanical testing, but only limited strain-to-failure (˜0.75 pct.) at quasi-static strain rates (10-3/s). The increased strain to failure at high strain rates is attributed to micro-flaw developments, including kinking, extensive axial splitting, and grain growth were observed after high strain rate deformation, and the significance of these mechanisms is considered.

  8. Ultrafine particle removal and generation by portable air cleaners

    Science.gov (United States)

    Waring, Michael S.; Siegel, Jeffrey A.; Corsi, Richard L.

    Portable air cleaners can both remove and generate pollutants indoors. To investigate these phenomena, we conducted a two-phase investigation in a 14.75 m 3 stainless steel chamber. In the first phase, particle size-resolved (12.6-514 nm diameter) clean air delivery rates (CADR) and efficiencies were determined, as were ozone emission rates, for two high-efficiency particle arresting (HEPA) filters, one electrostatic precipitator with a fan, and two ion generators without fans. The two HEPA air cleaners had count average CADR (standard deviation) of 188 (30) and 324 (44) m 3 h -1; the electrostatic precipitator 284 (62) m 3 h -1; and the two ion generators 41 (11) and 35 (13) m 3 h -1. The electrostatic precipitator emitted ozone at a rate of 3.8±0.2 mg h -1, and the two ion generators 3.3±0.2 and 4.3±0.2 mg h -1. Ozone initiates reactions with certain unsaturated organic compounds that produce ultrafine and fine particles, carbonyls, other oxidized products, and free radicals. During the second phase, five different ion generators were operated separately in the presence of a plug-in liquid or solid air freshener, representing a strong terpene source. For air exchange rates of between 0.49 and 0.96 h -1, three ion generators acted as steady-state net particle generators in the entire measured range of 4.61-157 nm, and two generated particles in the range of approximately 10 to 39-55 nm. Terpene and aldehyde concentrations were also sampled for one ion generator, and concentrations of terpenes decreased and formaldehyde increased. Given these results, the pollutant removal benefits of ozone-generating air cleaners may be outweighed by the generation of indoor pollution.

  9. Air pollutant concentrations near three Texas roadways, Part I: Ultrafine particles

    Science.gov (United States)

    Zhu, Yifang; Pudota, Jayanth; Collins, Donald; Allen, David; Clements, Andrea; DenBleyker, Allison; Fraser, Matt; Jia, Yuling; McDonald-Buller, Elena; Michel, Edward

    Vehicular emitted air pollutant concentrations were studied near three types of roadways in Austin, Texas: (1) State Highway 71 (SH-71), a heavily traveled arterial highway dominated by passenger vehicles; (2) Interstate 35 (I-35), a limited access highway north of Austin in Georgetown; and (3) Farm to Market Road 973 (FM-973), a heavily traveled surface roadway dominated by truck traffic. Air pollutants examined include carbon monoxide (CO), oxides of nitrogen (NO x), and carbonyl species in the gas-phase. In the particle phase, ultrafine particle (UFP) concentrations (diameter road were found to be the most important factors determining UFP concentrations near the roadways. Since wind directions were not consistent during the sampling periods, distances along wind trajectories from the roadway to the sampling points were used to study the decay characteristics of UFPs. Under perpendicular wind conditions, for all studied roadway types, particle number concentrations increased dramatically moving from the upwind side to the downwind side. The elevated particle number concentrations decay exponentially with increasing distances from the roadway with sharp concentration gradients observed within 100-150 m, similar to previously reported studies. A single exponential decay curve was found to fit the data collected from all three roadways very well under perpendicular wind conditions. No consistent pattern was observed for UFPs under parallel wind conditions. However, regardless of wind conditions, particle concentrations returned to background levels within a few hundred meters of the roadway. Within measured UFP size ranges, smaller particles (6-25 nm) decayed faster than larger ones (100-300 nm). Similar decay rates were observed among UFP number, surface, and volume.

  10. Timing of pathogen adaptation to a multicomponent treatment.

    Directory of Open Access Journals (Sweden)

    Romain Bourget

    Full Text Available The sustainable use of multicomponent treatments such as combination therapies, combination vaccines/chemicals, and plants carrying multigenic resistance requires an understanding of how their population-wide deployment affects the speed of the pathogen adaptation. Here, we develop a stochastic model describing the emergence of a mutant pathogen and its dynamics in a heterogeneous host population split into various types by the management strategy. Based on a multi-type Markov birth and death process, the model can be used to provide a basic understanding of how the life-cycle parameters of the pathogen population, and the controllable parameters of a management strategy affect the speed at which a pathogen adapts to a multicomponent treatment. Our results reveal the importance of coupling stochastic mutation and migration processes, and illustrate how their stochasticity can alter our view of the principles of managing pathogen adaptive dynamics at the population level. In particular, we identify the growth and migration rates that allow pathogens to adapt to a multicomponent treatment even if it is deployed on only small proportions of the host. In contrast to the accepted view, our model suggests that treatment durability should not systematically be identified with mutation cost. We show also that associating a multicomponent treatment with defeated monocomponent treatments can be more durable than associating it with intermediate treatments including only some of the components. We conclude that the explicit modelling of stochastic processes underlying evolutionary dynamics could help to elucidate the principles of the sustainable use of multicomponent treatments in population-wide management strategies intended to impede the evolution of harmful populations.

  11. A cluster randomised control trial of a multi-component weight management programme for adults with intellectual disabilities and obesity.

    Science.gov (United States)

    Harris, Leanne; Hankey, Catherine; Jones, Nathalie; Pert, Carol; Murray, Heather; Tobin, Janet; Boyle, Susan; Melville, Craig

    2017-08-01

    There have been few published controlled studies of multi-component weight management programmes that include an energy deficit diet (EDD), for adults with intellectual disabilities and obesity. The objective of this study was to conduct a single-blind, cluster randomised controlled trial comparing a multi-component weight management programme to a health education programme. Participants were randomised to either TAKE 5, which included an EDD or Waist Winners Too (WWToo), based on health education principles. Outcomes measured at baseline, 6 months (after a weight loss phase) and 12 months (after a 6-month weight maintenance phase), by a researcher blinded to treatment allocation, included: weight; BMI; waist circumference; physical activity; sedentary behaviour and health-related quality of life. The recruitment strategy was effective with fifty participants successfully recruited. Both programmes were acceptable to adults with intellectual disabilities, evidenced by high retention rates (90 %). Exploratory efficacy analysis revealed that at 12 months there was a trend for more participants in TAKE 5 (50·0 %) to achieve a clinically important weight loss of 5-10 %, in comparison to WWToo (20·8 %) (OR 3·76; 95 % CI 0·92, 15·30; 0·064). This study found that a multi-component weight management programme that included an EDD, is feasible and an acceptable approach to weight loss when tailored to meet the needs of adults with intellectual disabilities and obesity.

  12. Numerical modelling of multicomponent LNAPL dissolution kinetics ...

    Indian Academy of Sciences (India)

    Abstract. Characterization of aquifers contaminated by petroleum hydrocarbons is limited by the use of dissolution mass transfer correlations developed for single com- pounds without considering the effects of the mass transfer limitations in presence of other components. A one-dimensional implicit numerical model is ...

  13. Size evolution of ultrafine particles: Differential signatures of normal and episodic events

    International Nuclear Information System (INIS)

    Joshi, Manish; Khan, Arshad; Anand, S.; Sapra, B.K.

    2016-01-01

    The effect of fireworks on the aerosol number characteristics of atmosphere was studied for an urban mega city. Measurements were made at 50 m height to assess the local changes around the festival days. Apart from the increase in total number concentration and characteristic accumulation mode, short-term increase of ultrafine particle concentration was noted. Total number concentration varies an order of magnitude during the measurement period in which peak occurs at a frequency of approximately one per day. On integral scale, it seems not possible to distinguish an episodic (e.g. firework bursting induced aerosol emission) and a normal (ambient atmospheric changes) event. However these events could be differentiated on the basis of size evolution analysis around number concentration peaks. The results are discussed relative to past studies and inferences are drawn towards aerosol signatures of firework bursting. The short-term burst in ultrafine particle concentration can pose an inhalation hazard. - Highlights: • Effect of firework emissions on atmospheric aerosol characteristics was studied. • Significant increase in ultrafine particle concentration was observed during firework bursting. • Size distribution evolution analysis of number concentration peaks has been performed. • Differential signatures of normal and episodic event were noted. - Notable increase in ultrafine particle concentration during firework bursting was seen. Normal and episodic event could be differentiated on the basis of size evolution analysis.

  14. Effects of bran, shorts and feed flour by ultra-fine grinding on ...

    African Journals Online (AJOL)

    Wheat bran, shorts and feed flour are rich in dietary fiber and micronutrients. The effects of ultra-fine ground bran, shorts and feed flour on rheological characteristics of dough and bread qualities were investigated. Water absorption and dough development time gradually increased while mixing tolerance index and dough ...

  15. Effects of bran, shorts and feed flour by ultra-fine grinding on ...

    African Journals Online (AJOL)

    微软用户

    2012-02-21

    Feb 21, 2012 ... Full Length Research Paper. Effects of bran, shorts and feed flour by ultra-fine grinding on rheological characteristics of dough and bread qualities. Jinli Zhang, Hanxue Hou, Haizhou Dong* and Yangyong Dai. Department of Food Science and Engineering, Shandong Agricultural University, Tai'an, 271018 ...

  16. Soot, organics and ultrafine ash from air- and oxy-fired coal combustion

    Science.gov (United States)

    This paper is concerned with determining the effects of oxy-combustion of coal on the composition of the ultrafine fly ash. To this end, a 10 W externally heated entrained flow furnace was modified to allow the combustion of pulverized coal in flames under practically relevant s...

  17. Overview of fatigue behaviour of ultrafine-grained copper produced by severe plastic deformation

    Czech Academy of Sciences Publication Activity Database

    Lukáš, Petr; Kunz, Ludvík; Svoboda, Milan

    2008-01-01

    Roč. 567-568, - (2008), s. 9-16 ISSN 0255-5476. [MSMF /5./. Brno, 27.06.2007-29.06.2007] Institutional research plan: CEZ:AV0Z20410507 Keywords : Fatigue strength * Ultrafine-grained copper Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. Energy efficient reduction of fine and ultra-fine dust in a nursery

    NARCIS (Netherlands)

    Jacobs, P.; Phaff, J.C.; Voogt, M.H.

    2014-01-01

    An intervention study with a decentral electrostatic filter has been carried out in a nursery. The field study shows that it is possible to reach a reduction up to 80% of ultra-fine (<0.1 μm) and up to 68% for the PM1 and PM2,5-PM1 fractions at a relatively low energy consumption. These particle

  19. Organic-inorganic mesoporous silica nanostrands for ultrafine filtration of spherical nanoparticles.

    Science.gov (United States)

    El-Safty, Sherif A; Mekawy, Moataz; Yamaguchi, Akira; Shahat, Ahmed; Ogawa, Kazuyuki; Teramae, Norio

    2010-06-14

    We report a protocol for the direct synthesis of hexagonal silica nanostrands inside anodic alumina membranes using cationic surfactants as templates. When coated with layers of trimethylsilyl moieties, the nanostrands were a powerful tool for the ultrafine filtration of noble metal and semiconductor nanoparticles.

  20. Fatigue strength, microstructural stability and strain localization in ultrafine-grained copper

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík; Lukáš, Petr; Svoboda, Milan

    A 424, 1-2 (2006), s. 97-104 ISSN 0921-5093 R&D Projects: GA AV ČR(CZ) 1QS200410502; GA MŠk(CZ) 1P05ME804 Institutional research plan: CEZ:AV0Z20410507 Keywords : ultrafine-grained microstructure * ECAP * fatigue Subject RIV: JG - Metallurgy Impact factor: 1.490, year: 2006

  1. Stability of Microstructure of Ultrafine-Grained Copper Under Fatigue and Thermal Exposition

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík; Lukáš, Petr; Pantělejev, L.; Man, O.

    2011-01-01

    Roč. 2011, č. 47 (2011), 476–482 ISSN 0039-2103 Institutional research plan: CEZ:AV0Z20410507 Keywords : equal channel angular pressing * stability of ultrafine-grained microstructure * fatigue Subject RIV: JG - Metallurgy Impact factor: 1.103, year: 2011

  2. Preparation of Ultra-fine Calcium Carbonate by a Solvent-free ...

    African Journals Online (AJOL)

    The treatment of calcium chloride with sodium carbonate under solvent-free conditions with a supersonic airflow and at a low heating temperature leads to the synthesis of ultra-fine calcium carbonate. The reaction not only involves mild conditions, a simple operation, and high yields but also gives a high conversion rate.

  3. Fatigue damage of ultrafine-grain copper in very-high cycle fatigue region

    Czech Academy of Sciences Publication Activity Database

    Lukáš, Petr; Kunz, Ludvík; Navrátilová, Lucie; Bokůvka, O.

    2011-01-01

    Roč. 528, - (2011), s. 7036-7040 ISSN 0921-5093 R&D Projects: GA ČR GAP108/10/2001 Institutional research plan: CEZ:AV0Z20410507 Keywords : ultrafine-grained microstructure * ultrasonic fatigue * crack initiation * copper Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.003, year: 2011

  4. An evaluation of creep behavior in ultrafine-grained aluminum alloys processed by ECAP

    Czech Academy of Sciences Publication Activity Database

    Kawasaki, M.; Sklenička, Václav; Langdon, T. G.

    2010-01-01

    Roč. 45, č. 1 (2010), s. 271-274 ISSN 0022-2461 Institutional research plan: CEZ:AV0Z20410507 Keywords : creep * ultrafine-grained material * severe plastic deformation * equal-channel angular pressing Subject RIV: JG - Metallurgy Impact factor: 1.855, year: 2010

  5. Combustion of PTFE: The effects of gravity on ultrafine particle generation

    Science.gov (United States)

    McKinnon, Thomas; Todd, Paul; Oberdorster, Gunter

    1996-01-01

    The objective of this project is to obtain an understanding of the effect of gravity on the toxicity of ultrafine particle and gas phase materials produced when fluorocarbon polymers are thermally degraded or burned. The motivation for the project is to provide a basic technical foundation on which policies for spacecraft health and safety with regard to fire and polymers can be formulated.

  6. Ultrafine and Fine Particles and Hospital Admissions in Central Europe Results from the UFIREG Study

    Czech Academy of Sciences Publication Activity Database

    Lanzinger, S.; Schneider, A.; Breitner, S.; Stafoggia, M.; Erzen, I.; Dostál, Miroslav; Pastorková, Anna; Bastian, S.; Cyrys, J.; Zscheppang, A.; Kolodnitská, T.; Peters, A.

    2016-01-01

    Roč. 194, č. 10 (2016), s. 1233-1241 ISSN 1073-449X Institutional support: RVO:68378041 Keywords : ultrafine particles * particulate matter * hospital admissions * respiratory Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 13.204, year: 2016

  7. Microstructure changes in superplastically deformed ultrafine-grained Al-3Mg-0.2Sc alloy

    Czech Academy of Sciences Publication Activity Database

    Král, Petr; Dvořák, Jiří; Kvapilová, Marie; Horita, Z.; Sklenička, Václav

    2015-01-01

    Roč. 5, č. 3 (2015), s. 306-312 ISSN 2218-5046 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : ultrafine-grained microstructure * aluminium alloy * equal-channel angular pressing * electron back scatter diffraction Subject RIV: JJ - Other Materials

  8. Study of thermal stability of ultrafine-grained copper by means of electron back scattering diffraction

    Czech Academy of Sciences Publication Activity Database

    Man, O.; Pantělejev, L.; Kunz, Ludvík

    2010-01-01

    Roč. 51, č. 2 (2010), s. 209-213 ISSN 1345-9678 R&D Projects: GA AV ČR 1QS200410502 Institutional research plan: CEZ:AV0Z20410507 Keywords : ultra-fine grained copper * thermal stability of microstructure * electron back scattering diffraction * grain size * texture Subject RIV: JG - Metallurgy Impact factor: 0.779, year: 2010

  9. Fatigue behaviour of ultrafine-grained copper in very high cycle fatigue regime

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík; Lukáš, Petr; Bokůvka, O.

    2008-01-01

    Roč. 15, č. 4 (2008), s. 1-5 ISSN 1335-0803 R&D Projects: GA MŠk(CZ) 1P05ME804 Institutional research plan: CEZ:AV0Z20410507 Keywords : very high cycle fatigue * ultrafine-grained structure * ECAP * Copper Subject RIV: JG - Metallurgy

  10. Ultrafine particles of Ni and FeCr studied by positron annihilation

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard; Pedersen, N.J.; Sethi, S.A.

    1995-01-01

    Ultrafine particles of Ni and Fe80Cr20 have been produced by the gas condensation technique. After surface oxidation the paticles were heated in a reducing H2 atmosphere and positron lifetime and Doppler broadening measurements were carried out. Reduction of the oxide on the Ni powder takes place...

  11. Ultrafine-grained Al composites reinforced with in-situ Al3Ti filaments

    Czech Academy of Sciences Publication Activity Database

    Krizik, P.; Balog, M.; Nosko, M.; Riglos, M. V. C.; Dvořák, Jiří; Bajana, O.

    2016-01-01

    Roč. 657, MAR (2016), s. 6-14 ISSN 0921-5093 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Aluminum * Filament * In-situ metal matrix composite * Mechanical properties * Microstructure * Ultrafine-grained Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.094, year: 2016

  12. Controlled Exposure of Humans with Metabolic Syndrome to Concentrated Ultrafine Ambient Particulate Matter Causes Cardiovascular Effects

    Science.gov (United States)

    Background: Many studies have reported associations between PM2.5 and adverse cardiovascular effects. However there is increased concern that ultrafine PM (aerodynamic diameter less than 0.1 micron) may be disproportionately toxic relative to the 0.1 to 2.5 micron fraction of PM2...

  13. Synthesis of Magnetic Ultrafine Particles from a Ternary Gaseous Mixture Involving Cobalt Tricarbonyl Nitrosyl

    Czech Academy of Sciences Publication Activity Database

    Morita, H.; Sakano, H.; Murafa, Nataliya; Šubrt, Jan

    2014-01-01

    Roč. 27, č. 46 (2014), s. 477-483 ISSN 0914-9244 Institutional support: RVO:61388980 Keywords : gas phase photochemical reaction * magnetic ultrafine particle * cobalt tricarbonyl nitrosyl * tetraethylgermane * propenyltrimethylsilane Subject RIV: CA - Inorganic Chemistry Impact factor: 1.055, year: 2014

  14. Personal exposure to ultrafine particles in the workplace: exploring sampling techniques and strategies.

    Science.gov (United States)

    Brouwer, Derk H; Gijsbers, José H J; Lurvink, Marc W M

    2004-07-01

    Recently, toxicological and epidemiological studies on health effects related to particle exposure suggest that 'ultrafine particles' (particles with an aerodynamic diameter of measuring exposures against mass alone is not sufficient. It is also necessary to consider exposures against surface area and number concentration. From earlier research it was hypothesized that results on number concentration and particle distributions may vary with distance to the source, limiting the reliability of estimates of personal exposure from results which were obtained using static measurement equipment. Therefore, a workplace study was conducted to explore the performance of measurement methods in a multi-source emission scenario as part of a sampling strategy to estimate personal exposure. In addition, a laboratory study was conducted to determine possible influences of both distance to source and time course on particle number concentration and particle size distribution. In both studies different measurement equipment and techniques were used to characterize (total) particle number concentration. These included a condensation particle counter (CPC), a scanning mobility particle sizer (SMPS) and an electrical low pressure impactor (ELPI). For the present studies CPC devices seemed to perform well for the identification of particle emission sources. The range of ultrafine particle number concentration can be detected by both SMPS and ELPI. An important advantage of the ELPI is that aerosols with ultrafine sizes can be collected for further analysis. Specific surface area of the aerosols can be estimated using gas adsorption analysis; however, with this technique ultrafine particles cannot be distinguished from particles with non-ultrafine sizes. Consequently, estimates based on samples collected from the breathing zone and scanning electron microscopic analysis may give a more reliable estimate of the specific surface area of the ultrafine particles responsible for personal

  15. Electrospinning of oriented and nonoriented ultrafine fibers of biopolymers

    Science.gov (United States)

    Vu, David

    2005-07-01

    Chitosan has long been known as a biocompatible and biodegradable material suitable for tissue engineering applications. Unfortunately, conventional chitosan solutions cannot be used for electrospinning due to their high conductivity, viscosity and surface tension. We have developed a method to produce clear chitosan solutions with conductivities, surface tension and viscosities that facilitate their processing into micron and submicron fibers via electrospinning. Acetic acid, carbon dioxide and organic solvents are key ingredients in preparing the chitosan solutions. Oriented and non oriented chitosan fibers were produced with the ultimate goal of designing a suitable tissue engineering scaffold. Circularly oriented, continuous, and aligned nanofibers were produced via this technique in the form of a thin membrane or fibrous "mat". Chitosan fiber diameters ranged from 5 micrometers down to 100 nanometers. The structure and mechanical properties of oriented and randomly aligned chitosan fiber deposits could potentially be exploited for cartilage tissue engineering. Ultrafine fibers of starch acetate (SA) also were prepared by the electrospinning process. In this study, solvent mixtures based on DMF, DMSO, pyrindine, acetic acid, acetone, THF, DMC, chloroform were used. A two-solvent formulation was used to study the effect of viscosity, surface tension, and conductivity to the fiber diameter. Also, water and ethanol were used to decrease the boiling point of the solvent, and to make bundled fibers. Several techniques such as scanning electron microscopy, conductmetry, viscometry, and tensiometry were used in this study. The results showed that the combined effects of viscosity, surface tension, and conductivity are of great importance in controlling the diameter of the fibers. We were able to produce SA fibers that was less than 40 nm in diameter. The dependence of fiber diameter on flow-rate, electric field and solvents also was investigated. A rotating disk and a

  16. Release of ultrafine particles from three simulated building processes

    International Nuclear Information System (INIS)

    Kumar, Prashant; Mulheron, Mike; Som, Claudia

    2012-01-01

    Building activities are recognised to produce coarse particulate matter but less is known about the release of airborne ultrafine particles (UFPs; those below 100 nm in diameter). For the first time, this study has investigated the release of particles in the 5–560 nm range from three simulated building activities: the crushing of concrete cubes, the demolition of old concrete slabs, and the recycling of concrete debris. A fast response differential mobility spectrometer (Cambustion DMS50) was used to measure particle number concentrations (PNC) and size distributions (PNDs) at a sampling frequency of 10 Hz in a confined laboratory room providing controlled environment and near–steady background PNCs. The sampling point was intentionally kept close to the test samples so that the release of new UFPs during these simulated processes can be quantified. Tri–modal particle size distributions were recorded for all cases, demonstrating different peak diameters in fresh nuclei ( 4 cm −3 . These background modal peaks shifted towards the larger sizes during the work periods (i.e. actual experiments) and the total PNCs increased between 2 and 17 times over the background PNCs for different activities. After adjusting for background concentrations, the net release of PNCs during cube crushing, slab demolition, and ‘dry’ and ‘wet’ recycling events were measured as ∼0.77, 19.1, 22.7 and 1.76 (×10 4 ) cm −3 , respectively. The PNDs were converted into particle mass concentrations (PMCs). While majority of new PNC release was below 100 nm (i.e. UFPs), the bulk of new PMC emissions were constituted by the particles over 100 nm; ∼95, 79, 73 and 90% of total PNCs, and ∼71, 92, 93 and 91% of total PMCs, for cube crushing, slab demolition, dry recycling and wet recycling, respectively. The results of this study firmly elucidate the release of UFPs and raise a need for further detailed studies and designing health and safety related exposure guidelines for

  17. Microstructure of warm rolling and pearlitic transformation of ultrafine-grained GCr15 steel

    International Nuclear Information System (INIS)

    Sun, Jun-Jie; Lian, Fu-Liang; Liu, Hong-Ji; Jiang, Tao; Guo, Sheng-Wu; Du, Lin-Xiu; Liu, Yong-Ning

    2014-01-01

    Pearlitic transformation mechanisms have been investigated in ultra-fine grained GCr15 steel. The ultrafine-grained steel, whose grain size was less than 1 μm, was prepared by thermo-mechanical treatment at 873 K and then annealing at 923 K for 2 h. Pearlitic transformation was conducted by reheating the ultra-fine grained samples at 1073 K and 1123 K for different periods of time and then cooling in air. Scanning electron microscope observation shows that normal lamellar pearlite, instead of granular cementite and ferrite, cannot be formed when the grain size is approximately less than 4(± 0.6) μm, which yields a critical grain size for normal lamellar pearlitic transformations in this chromium alloyed steel. The result confirms that grain size has a great influence on pearlitic transformation by increasing the diffusion rate of carbon atoms in the ultra-fine grained steel, and the addition of chromium element doesn't change this pearlitic phase transformation rule. Meanwhile, the grain growth rate is reduced by chromium alloying, which is beneficial to form fine grains during austenitizing, thus it facilitating pearlitic transformation by divorced eutectoid transformation. Moreover, chromium element can form a relatively high gradient in the frontier of the undissolved carbide, which promotes carbide formation in the frontier of the undissolved carbide, i.e., chromium promotes divorced eutectoid transformation. - Highlights: • Ultrafine-grained GCr15 steel was obtained by warm rolling and annealing technology. • Reduction of grain size makes pearlite morphology from lamellar to granular. • Adding Cr does not change normal pearlitic phase transformation rule in UFG steel. • Cr carbide resists grain growth and facilitates pearlitic transformation by DET

  18. Multicomponent isotope separation in matched abundance ratio cascades composed of stages with large separation factors

    International Nuclear Information System (INIS)

    Von Halle, E.

    1987-06-01

    The concept of the matched abundance ratio cascade and the system of equations for performing multicomponent productivity calculations upon them has proven extremely useful for analyzing the behavior of gaseous diffusion plants in which the stage separation factors are very nearly equal to unity. Recent interest in the gas centrifuge process, in which the separation factor of a single centrifuge can be relatively large, makes desirable the extension of the theory of the matched abundance ratio cascade to cascades composed of stages with large separation factors. Equations permit the calculation of the productivity for simple cascades composed of stages with large separation factors. The concentration gradient of each of the isotopic species present can be calculated and the cascade description can be determined. An illustrative example dealing with the separation of the isotopes of tungsten in a cascade composed of gas centrifuges is included

  19. CONTROL OF LASER RADIATION PARAMETERS: Acousto-optic modulation of multicomponent Ar laser radiation

    Science.gov (United States)

    Kotov, V. M.

    1995-06-01

    Polarisation-independent acousto-optic diffraction, in which optical radiation propagates along the optic axis of a gyrotropic crystal and an acoustic wave travels along a tangent to 'inner' wave-vector surfaces of the crystal, is considered. This diffraction geometry is shown to be optimal for the modulation of multicomponent laser radiation. The results are given of theoretical and experimental investigations of acousto-optic diffraction of six-component Ar laser radiation in the blue—green part of the spectrum, propagating in a TeO2 single crystal. The highest diffraction efficiency (90%) is reported for a transverse acoustic wave of 90 MHz frequency when the acoustic wavefront is tilted at an angle of ~1.2o to the optic axis of the crystal. A method of 'angular correction' of the direction of propagation of the diffracted rays, which makes it possible to concentrate all the diffracted radiation in one spot, is proposed.

  20. Multicomponent, Enantioselective Michael-Michael-Aldol-β-Lactonizations Delivering Complex β-Lactones.

    Science.gov (United States)

    Van, Khoi N; Romo, Daniel

    2018-01-19

    Optically active, tertiary amine Lewis bases react with unsaturated acid chlorides to deliver chiral, α,β-unsaturated acylammonium salts. These intermediates participate in a catalytic, enantioselective, three-component process delivering bi- and tricyclic β-lactones through a Michael-Michael-aldol-β-lactonization. In a single operation, the described multicomponent, organocascade process forms complex bi- and tricyclic β-lactones by generating four new bonds, two rings, and up to four contiguous stereocenters. In the racemic series, yields of 22-75% were achieved using 4-pyrrolidinopyridine as Lewis base. In the enantioselective series employing isothiourea catalysts, a kinetic resolution of the initially formed racemic Michael adduct appears operative, providing yields of 46% to quantitative (based on 50% max) with up to 94:6 er. Some evidence for a dynamic kinetic asymmetric transformation for tricyclic-β-lactone 1d was obtained following optimization (yields up to 61%, 94:6 er) through a presumed reversible Michael.

  1. Electrostatic twisted modes in multi-component dusty plasmas

    International Nuclear Information System (INIS)

    Ayub, M. K.; Ali, S.; Ikram, M.

    2016-01-01

    Various electrostatic twisted modes are re-investigated with finite orbital angular momentum in an unmagnetized collisionless multi-component dusty plasma, consisting of positive/negative charged dust particles, ions, and electrons. For this purpose, hydrodynamical equations are employed to obtain paraxial equations in terms of density perturbations, while assuming the Gaussian and Laguerre-Gaussian (LG) beam solutions. Specifically, approximated solutions for potential problem are studied by using the paraxial approximation and expressed the electric field components in terms of LG functions. The energy fluxes associated with these modes are computed and corresponding expressions for orbital angular momenta are derived. Numerical analyses reveal that radial/angular mode numbers as well as dust number density and dust charging states strongly modify the LG potential profiles attributed to different electrostatic modes. Our results are important for understanding particle transport and energy transfer due to wave excitations in multi-component dusty plasmas

  2. Phase behavior of multicomponent membranes: Experimental and computational techniques

    DEFF Research Database (Denmark)

    Bagatolli, Luis; Kumar, P.B. Sunil

    2009-01-01

    membranes. Current increase in interest in the domain formation in multicomponent membranes also stems from the experiments demonstrating liquid ordered-liquid disordered coexistence in mixtures of lipids and cholesterol and the success of several computational models in predicting their behavior....... This review includes basic foundations on membrane model systems and experimental approaches applied in the membrane research area, stressing on recent advances in the experimental and computational techniques....

  3. Ab initio calculations for search optimization of multicomponent alloy configurations

    Science.gov (United States)

    Nikonov, A. Yu.; Zharmukhambetova, A. M.; Dmitriev, A. I.

    2016-11-01

    The paper presents an algorithm for optimization of searching configurations of multicomponent alloys that have a predetermined value of physical and mechanical properties. Values obtained by Exact MT Orbitals (EMTO) were used for calculations. The algorithm efficiency is demonstrated on an example of estimating the bulk modulus of a three-component alloy based on Ti, Nb and Zr. It is shown that the use of the algorithm can in some cases reduce the amount of calculations by 10 times or more.

  4. Hygroscopic behavior of multicomponent organic aerosols and their internal mixtures with ammonium sulfate

    Science.gov (United States)

    Jing, Bo; Tong, Shengrui; Liu, Qifan; Li, Kun; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

    2016-03-01

    Water-soluble organic compounds (WSOCs) are important components of organics in the atmospheric fine particulate matter. Although WSOCs play an important role in the hygroscopicity of aerosols, knowledge on the water uptake behavior of internally mixed WSOC aerosols remains limited. Here, the hygroscopic properties of single components such as levoglucosan, oxalic acid, malonic acid, succinic acid, phthalic acid, and multicomponent WSOC aerosols mainly involving oxalic acid are investigated with the hygroscopicity tandem differential mobility analyzer (HTDMA). The coexisting hygroscopic species including levoglucosan, malonic acid, and phthalic acid have a strong influence on the hygroscopic growth and phase behavior of oxalic acid, even suppressing its crystallization completely during the drying process. The phase behaviors of oxalic acid/levoglucosan mixed particles are confirmed by infrared spectra. The discrepancies between measured growth factors and predictions from Extended Aerosol Inorganics Model (E-AIM) with the Universal Quasi-Chemical Functional Group Activity Coefficient (UNIFAC) method and Zdanovskii-Stokes-Robinson (ZSR) approach increase at medium and high relative humidity (RH) assuming oxalic acid in a crystalline solid state. For the internal mixture of oxalic acid with levoglucosan or succinic acid, there is enhanced water uptake at high RH compared to the model predictions based on reasonable oxalic acid phase assumption. Organic mixture has more complex effects on the hygroscopicity of ammonium sulfate than single species. Although hygroscopic species such as levoglucosan account for a small fraction in the multicomponent aerosols, they may still strongly influence the hygroscopic behavior of ammonium sulfate by changing the phase state of oxalic acid which plays the role of "intermediate" species. Considering the abundance of oxalic acid in the atmospheric aerosols, its mixtures with hygroscopic species may significantly promote water uptake

  5. Hygroscopic behavior of multicomponent organic aerosols and their internal mixtures with ammonium sulfate

    Directory of Open Access Journals (Sweden)

    B. Jing

    2016-03-01

    Full Text Available Water-soluble organic compounds (WSOCs are important components of organics in the atmospheric fine particulate matter. Although WSOCs play an important role in the hygroscopicity of aerosols, knowledge on the water uptake behavior of internally mixed WSOC aerosols remains limited. Here, the hygroscopic properties of single components such as levoglucosan, oxalic acid, malonic acid, succinic acid, phthalic acid, and multicomponent WSOC aerosols mainly involving oxalic acid are investigated with the hygroscopicity tandem differential mobility analyzer (HTDMA. The coexisting hygroscopic species including levoglucosan, malonic acid, and phthalic acid have a strong influence on the hygroscopic growth and phase behavior of oxalic acid, even suppressing its crystallization completely during the drying process. The phase behaviors of oxalic acid/levoglucosan mixed particles are confirmed by infrared spectra. The discrepancies between measured growth factors and predictions from Extended Aerosol Inorganics Model (E-AIM with the Universal Quasi-Chemical Functional Group Activity Coefficient (UNIFAC method and Zdanovskii–Stokes–Robinson (ZSR approach increase at medium and high relative humidity (RH assuming oxalic acid in a crystalline solid state. For the internal mixture of oxalic acid with levoglucosan or succinic acid, there is enhanced water uptake at high RH compared to the model predictions based on reasonable oxalic acid phase assumption. Organic mixture has more complex effects on the hygroscopicity of ammonium sulfate than single species. Although hygroscopic species such as levoglucosan account for a small fraction in the multicomponent aerosols, they may still strongly influence the hygroscopic behavior of ammonium sulfate by changing the phase state of oxalic acid which plays the role of "intermediate" species. Considering the abundance of oxalic acid in the atmospheric aerosols, its mixtures with hygroscopic species may significantly

  6. High Performance Multi-GPU SpMV for Multi-component PDE-Based Applications

    KAUST Repository

    Abdelfattah, Ahmad

    2015-07-25

    Leveraging optimization techniques (e.g., register blocking and double buffering) introduced in the context of KBLAS, a Level 2 BLAS high performance library on GPUs, the authors implement dense matrix-vector multiplications within a sparse-block structure. While these optimizations are important for high performance dense kernel executions, they are even more critical when dealing with sparse linear algebra operations. The most time-consuming phase of many multicomponent applications, such as models of reacting flows or petroleum reservoirs, is the solution at each implicit time step of large, sparse spatially structured or unstructured linear systems. The standard method is a preconditioned Krylov solver. The Sparse Matrix-Vector multiplication (SpMV) is, in turn, one of the most time-consuming operations in such solvers. Because there is no data reuse of the elements of the matrix within a single SpMV, kernel performance is limited by the speed at which data can be transferred from memory to registers, making the bus bandwidth the major bottleneck. On the other hand, in case of a multi-species model, the resulting Jacobian has a dense block structure. For contemporary petroleum reservoir simulations, the block size typically ranges from three to a few dozen among different models, and still larger blocks are relevant within adaptively model-refined regions of the domain, though generally the size of the blocks, related to the number of conserved species, is constant over large regions within a given model. This structure can be exploited beyond the convenience of a block compressed row data format, because it offers opportunities to hide the data motion with useful computations. The new SpMV kernel outperforms existing state-of-the-art implementations on single and multi-GPUs using matrices with dense block structure representative of porous media applications with both structured and unstructured multi-component grids.

  7. Multicomponent Fitness Training Improves Walking Economy in Older Adults.

    Science.gov (United States)

    Valenti, Giulio; Bonomi, Alberto Giovanni; Westerterp, Klaas Roelof

    2016-07-01

    Walking economy declines with increasing age, possibly leading to mobility limitation in older adults. Multicomponent fitness training could delay the decline in walking economy. This study aimed to determine the effect of multicomponent fitness training on walking economy in older adults. Participants were untrained adults, age 50 to 83 yr (N = 26, 10 males, age = 63 ± 6 yr, BMI = 25.6 ± 2.1 kg·m, mean ± SD). A control group was also recruited (N = 16, 9 males, age = 66 ± 10 yr, BMI = 25.4 ± 3.0 kg·m), matching the intervention group for age, weight, body composition, and fitness. The intervention group followed a multicomponent fitness program of 1 h, twice per week during 1 yr. The control group did not take part in any physical training. Fat-free mass, walking economy, and maximal oxygen uptake (V˙O2max) were measured in both groups before and after the year. Walking economy was measured with indirect calorimetry as the lowest energy needed to displace 1 kg of body mass for 1 m while walking on a treadmill. The data were compared between the two groups with repeated-measures ANOVA. Thirty-two subjects completed all measurements. There was an interaction between the effects of time and group on V˙O2max (P economy (P economy. Thus, training programs could delay mobility limitation with increasing age.

  8. Enhanced protective properties of epoxy/polyaniline-camphorsulfonate nanocomposite coating on an ultrafine-grained metallic surface

    Energy Technology Data Exchange (ETDEWEB)

    Pour-Ali, Sadegh, E-mail: pourali2020@ut.ac.ir; Kiani-Rashid, Alireza; Babakhani, Abolfazl; Davoodi, Ali

    2016-07-15

    Highlights: • Preparing mild steel surface with ultrafine grains by wire brushing process. • Performance of a smart coating on micro- and nano-crystalline surfaces. • Corrosion evaluation, surface analysis and ac/dc electrochemical measurements. • Ultrafine surface grains improve protective behavior of epoxy/PANI-CSA coating. - Abstract: An ultrafine-grained surface layer on mild steel substrate with average grain size of 77 nm was produced through wire brushing process. Surface grain size was determined through transmission electron microscopy and X-ray diffraction methods. This substrate was coated with epoxy and an in situ synthesized epoxy/polyaniline-camphorsulfonate (epoxy/PANI-CSA) nanocomposite. The corrosion behavior was studied by open circuit potential, potentiodynamic polarization and impedance measurements. Results of electrochemical tests evidenced the enhanced protective properties of epoxy/PANI-CSA coating on the substrate with ultrafine-grained surface.

  9. Direct printing of patterned three-dimensional ultrafine fibrous scaffolds by stable jet electrospinning for cellular ingrowth

    International Nuclear Information System (INIS)

    Yuan, Huihua; Zhou, Qihui; Li, Biyun; Bao, Min; Lou, Xiangxin; Zhang, Yanzhong

    2015-01-01

    Electrospinning has been widely used to produce ultrafine fibers in microscale and nanoscale; however, traditional electrospinning processes are currently beset by troublesome limitations in fabrication of 3D periodic porous structures because of the chaotic nature of the electrospinning jet. Here we report a novel strategy to print 3D poly(L-lactic acid) (PLLA) ultrafine fibrous scaffolds with the fiber diameter of approximately 2 μm by combining a stable jet electrospinning method and an X-Y stage technique. Our approach allows linearly deposited electrospun ultrafine fibers to assemble into 3D structures with tunable pore sizes and desired patterns. Process conditions (e.g., plotting speed, feeding rate, and collecting distance) were investigated in order to achieve stable jet printing of ultrafine PLLA fibers. The proposed 3D scaffold was successfully used for cell penetration and growth, demonstrating great potential for tissue engineering applications. (paper)

  10. The Effect of Ultrafine Magnesium Hydroxide on the Tensile Properties and Flame Retardancy of Wood Plastic Composites

    Directory of Open Access Journals (Sweden)

    Zhiping Wu

    2014-01-01

    Full Text Available The effect of ultrafine magnesium hydroxide (UMH and ordinary magnesium hydroxide (OMH on the tensile properties and flame retardancy of wood plastic composites (WPC were investigated by tensile test, oxygen index tester, cone calorimeter test, and thermogravimetric analysis. The results showed that ultrafine magnesium hydroxide possesses strengthening and toughening effect of WPC. Scanning electron micrograph (SEM of fracture section of samples provided the positive evidence that the tensile properties of UMH/WPC are superior to that of WPC and OMH/WPC. The limited oxygen index (LOI and cone calorimeter test illustrated that ultrafine magnesium hydroxide has stronger flame retardancy and smoke suppression effect of WPC compared to that of ordinary magnesium hydroxide. The results of thermogravimetric analysis implied that ultrafine magnesium hydroxide can improve the char structure which plays an important role in reducing the degradation speed of the inner matrix during combustion process and increases the char residue at high temperature.

  11. Sliding dynamics on ultrafine grained Al-6 wt % Mg made by equal channel single pressing

    Science.gov (United States)

    Filippov, A. V.; Tarasov, S. Yu.; Podgornykh, O. A.; Chazov, P. A.; Shamarin, N. N.; Filippova, E. O.

    2017-12-01

    The effect of ECAP pass number on wear, microhardness and tribological dynamic behavior of UFG Al- 6 wt % Mg alloy has been studied. The UFG Al-6 wt % Mg samples demonstrated higher wear resistance after 4 and 8 ECAP passes as compared to as-received alloys state. The dynamics of sliding and loudness level generated in sliding showed moderate increase of vibrations and noise on ECAP UFG samples.

  12. Similarity Reductions of (2+1)-Dimensional Multi-component Broer Kaup System

    Science.gov (United States)

    Dong, Zhong-Zhou; Chen, Yong; Wang, Ling

    2008-10-01

    Painlevé property of the (2+1)-dimensional multi-component Broer Kaup (BK) system is considered by using the standard Weiss Kruskal approaches. Applying the Clarkson and Kruskal (CK) direct method to the (2+1)-dimensional multi-component BK system, some types of similarity reductions are obtained. By solving the reductions, one can get the solutions of the (2+1)-dimensional multi-component BK system.

  13. Ultrafine carbon particles promote rotenone-induced dopamine neuronal loss through activating microglial NADPH oxidase

    International Nuclear Information System (INIS)

    Wang, Yinxi; Liu, Dan; Zhang, Huifeng; Wang, Yixin; Wei, Ling; Liu, Yutong; Liao, Jieying; Gao, Hui-Ming; Zhou, Hui

    2017-01-01

    Background: Atmospheric ultrafine particles (UFPs) and pesticide rotenone were considered as potential environmental risk factors for Parkinson's disease (PD). However, whether and how UFPs alone and in combination with rotenone affect the pathogenesis of PD remains largely unknown. Methods: Ultrafine carbon black (ufCB, a surrogate of UFPs) and rotenone were used individually or in combination to determine their roles in chronic dopaminergic (DA) loss in neuron-glia, and neuron-enriched, mix-glia cultures. Immunochemistry using antibody against tyrosine hydroxylase was performed to detect DA neuronal loss. Measurement of extracellular superoxide and intracellular reactive oxygen species (ROS) were performed to examine activation of NADPH oxidase. Genetic deletion and pharmacological inhibition of NADPH oxidase and MAC-1 receptor in microglia were employed to examine their role in DA neuronal loss triggered by ufCB and rotenone. Results: In rodent midbrain neuron-glia cultures, ufCB and rotenone alone caused neuronal death in a dose-dependent manner. In particularly, ufCB at doses of 50 and 100 μg/cm 2 induced significant loss of DA neurons. More importantly, nontoxic doses of ufCB (10 μg/cm 2 ) and rotenone (2 nM) induced synergistic toxicity to DA neurons. Microglial activation was essential in this process. Furthermore, superoxide production from microglial NADPH oxidase was critical in ufCB/rotenone-induced neurotoxicity. Studies in mix-glia cultures showed that ufCB treatment activated microglial NADPH oxidase to induce superoxide production. Firstly, ufCB enhanced the expression of NADPH oxidase subunits (gp91 phox , p47 phox and p40 phox ); secondly, ufCB was recognized by microglial surface MAC-1 receptor and consequently promoted rotenone-induced p47 phox and p67 phox translocation assembling active NADPH oxidase. Conclusion: ufCB and rotenone worked in synergy to activate NADPH oxidase in microglia, leading to oxidative damage to DA neurons. Our

  14. Association of modeled long-term personal exposure to ultrafine particles with inflammatory and coagulation biomarkers.

    Science.gov (United States)

    Lane, Kevin J; Levy, Jonathan I; Scammell, Madeleine K; Peters, Junenette L; Patton, Allison P; Reisner, Ellin; Lowe, Lydia; Zamore, Wig; Durant, John L; Brugge, Doug

    2016-01-01

    Long-term exposure to fine particulate matter has been linked to cardiovascular disease and systemic inflammatory responses; however, evidence is limited regarding the effects of long-term exposure to ultrafine particulate matter (UFP, <100nm). We used a cross-sectional study design to examine the association of long-term exposure to near-highway UFP with measures of systemic inflammation and coagulation. We analyzed blood samples from 408 individuals aged 40-91years living in three near-highway and three urban background areas in and near Boston, Massachusetts. We conducted mobile monitoring of particle number concentration (PNC) in each area, and used the data to develop and validate highly resolved spatiotemporal (hourly, 20m) PNC regression models. These models were linked with participant time-activity data to determine individual time-activity adjusted (TAA) annual average PNC exposures. Multivariable regression modeling and stratification were used to assess the association between TAA-PNC and single peripheral blood measures of high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), tumor-necrosis factor alpha receptor II (TNFRII) and fibrinogen. After adjusting for age, sex, education, body mass index, smoking and race/ethnicity, an interquartile-range (10,000particles/cm(3)) increase in TAA-PNC had a positive non-significant association with a 14.0% (95% CI: -4.6%, 36.2%) positive difference in hsCRP, an 8.9% (95% CI: -0.4%, 10.9%) positive difference in IL-6, and a 5.1% (95% CI: -0.4%, 10.9%) positive difference in TNFRII. Stratification by race/ethnicity revealed that TAA-PNC had larger effect estimates for all three inflammatory markers and was significantly associated with hsCRP and TNFRII in white non-Hispanic, but not East Asian participants. Fibrinogen had a negative non-significant association with TAA-PNC. Our findings suggest an association between annual average near-highway TAA-PNC and subclinical inflammatory markers of CVD risk

  15. Elastic properties of paramagnetic austenitic steel at finite temperature: Longitudinal spin fluctuations in multicomponent alloys

    Science.gov (United States)

    Dong, Zhihua; Schönecker, Stephan; Chen, Dengfu; Li, Wei; Long, Mujun; Vitos, Levente

    2017-11-01

    We propose a first-principles framework for longitudinal spin fluctuations (LSFs) in disordered paramagnetic (PM) multicomponent alloy systems and apply it to investigate the influence of LSFs on the temperature dependence of two elastic constants of PM austenitic stainless steel Fe15Cr15Ni. The magnetic model considers individual fluctuating moments in a static PM medium with first-principles-derived LSF energetics in conjunction with describing chemical disorder and randomness of the transverse magnetic component in the single-site alloy formalism and disordered local moment (DLM) picture. A temperature-sensitive mean magnetic moment is adopted to accurately represent the LSF state in the elastic-constant calculations. We make evident that magnetic interactions between an LSF impurity and the PM medium are weak in the present steel alloy. This allows gaining accurate LSF energetics and mean magnetic moments already through a perturbation from the static DLM moments instead of a tedious self-consistent procedure. We find that LSFs systematically lower the cubic shear elastic constants c' and c44 by ˜6 GPa in the temperature interval 300-1600 K, whereas the predominant mechanism for the softening of both elastic constants with temperature is the magneto-volume coupling due to thermal lattice expansion. We find that non-negligible local magnetic moments of Cr and Ni are thermally induced by LSFs, but they exert only a small influence on the elastic properties. The proposed framework exhibits high flexibility in accurately accounting for finite-temperature magnetism and its impact on the mechanical properties of PM multicomponent alloys.

  16. Extended Shvab-Zel'dovich formulation for multicomponent-fuel diffusion flames

    Energy Technology Data Exchange (ETDEWEB)

    Fachini, Fernando F. [Instituto Nacional de Pesquisas Espaciais, Rod. Presidente Dutra Km 40, 12630-000 Cachoeira Paulista, SP (Brazil)

    2007-03-15

    In this paper an extension of the Shvab-Zel'dovich formulation is presented. This extended formulation, based on the Burke-Schumann kinetic mechanism, describes the combustion of multicomponent fuels in a diffusion flame in terms of mixture fraction and the excess enthalpy. Under the condition of Burke-Schumann kinetic mechanism, the multicomponent fuel is burned in a single flame. The model is applied to a diffusion flame generated by the burning of mixtures of n-heptane and hydrogen diluted in nitrogen in a counterflow configuration. Due to the very small ratio of the hydrogen molecular weight to the n-heptane molecular weight, small quantities of hydrogen (in terms of mass) in the mixture does not change significantly the properties related to the mass, like as the total heat released per unit of mass at the flame. However, properties related to the hydrogen mole fraction does change expressively with small quantities, like as the radiative energy loss from the hot region around the flame. The results show the flame properties as a function of the reciprocal scalar dissipation and hydrogen quantity in the mixture. It is observed that, by reducing the reciprocal scalar dissipation, the radiative energy loss decreases and by increasing the presence of the hydrogen, the sensitivity of the flame properties with the reciprocal scalar dissipation reduces. It is also revealed by the results, the effects of the potentiated preferential hydrogen mass diffusion in compositions in which nitrogen and n-heptane are the majority species, and the potentiated preferential n-heptane thermal diffusion in compositions in which nitrogen and hydrogen are the majority species, on the flame properties. Although, this work do not treat the extinction problem, the fluid dynamical results will be properly handled to provide information about the reciprocal scalar dissipation and the Linan's parameter necessary for future flame stability analyses. (author)

  17. Rational solutions to two- and one-dimensional multicomponent Yajima–Oikawa systems

    International Nuclear Information System (INIS)

    Chen, Junchao; Chen, Yong; Feng, Bao-Feng; Maruno, Ken-ichi

    2015-01-01

    Exact explicit rational solutions of two- and one-dimensional multicomponent Yajima–Oikawa (YO) systems, which contain multi-short-wave components and single long-wave one, are presented by using the bilinear method. For two-dimensional system, the fundamental rational solution first describes the localized lumps, which have three different patterns: bright, intermediate and dark states. Then, rogue waves can be obtained under certain parameter conditions and their behaviors are also classified to above three patterns with different definition. It is shown that the simplest (fundamental) rogue waves are line localized waves which arise from the constant background with a line profile and then disappear into the constant background again. In particular, two-dimensional intermediate and dark counterparts of rogue wave are found with the different parameter requirements. We demonstrate that multirogue waves describe the interaction of several fundamental rogue waves, in which interesting curvy wave patterns appear in the intermediate times. Different curvy wave patterns form in the interaction of different types fundamental rogue waves. Higher-order rogue waves exhibit the dynamic behaviors that the wave structures start from lump and then retreat back to it, and this transient wave possesses the patterns such as parabolas. Furthermore, different states of higher-order rogue wave result in completely distinguishing lumps and parabolas. Moreover, one-dimensional rogue wave solutions with three states are constructed through the further reduction. Specifically, higher-order rogue wave in one-dimensional case is derived under the parameter constraints. - Highlights: • Exact explicit rational solutions of two-and one-dimensional multicomponent Yajima–Oikawa systems. • Two-dimensional rogue wave contains three different patterns: bright, intermediate and dark states. • Multi- and higher-order rogue waves exhibit distinct dynamic behaviors in two-dimensional case

  18. Site-specific transition metal occupation in multicomponent pyrophosphate for improved electrochemical and thermal properties in lithium battery cathodes: a combined experimental and theoretical study.

    Science.gov (United States)

    Shakoor, Rana A; Kim, Heejin; Cho, Woosuk; Lim, Soo Yeon; Song, Hannah; Lee, Jung Woo; Kang, Jeung Ku; Kim, Yong-Tae; Jung, Yousung; Choi, Jang Wook

    2012-07-18

    As an attempt to develop lithium ion batteries with excellent performance, which is desirable for a variety of applications including mobile electronics, electrical vehicles, and utility grids, the battery community has continuously pursued cathode materials that function at higher potentials with efficient kinetics for lithium insertion and extraction. By employing both experimental and theoretical tools, herein we report multicomponent pyrophosphate (Li(2)MP(2)O(7), M = Fe(1/3)Mn(1/3)Co(1/3)) cathode materials with novel and advantageous properties as compared to the single-component analogues and other multicomponent polyanions. Li(2)Fe(1/3)Mn(1/3)Co(1/3)P(2)O(7) is formed on the basis of a solid solution among the three individual transition-metal-based pyrophosphates. The unique crystal structure of pyrophosphate and the first principles calculations show that different transition metals have a tendency to preferentially occupy either octahedral or pyramidal sites, and this site-specific transition metal occupation leads to significant improvements in various battery properties: a single-phase mode for Li insertion/extraction, improved cell potentials for Fe(2+)/Fe(3+) (raised by 0.18 eV) and Co(2+)/Co(3+) (lowered by 0.26 eV), and increased activity for Mn(2+)/Mn(3+) with significantly reduced overpotential. We reveal that the favorable energy of transition metal mixing and the sequential redox reaction for each TM element with a sufficient redox gap is the underlying physical reason for the preferential single-phase mode of Li intercalation/deintercalation reaction in pyrophosphate, a general concept that can be applied to other multicomponent systems. Furthermore, an extremely small volume change of ~0.7% between the fully charged and discharged states and the significantly enhanced thermal stability are observed for the present material, the effects unseen in previous multicomponent battery materials.

  19. Size evolution of ultrafine particles: Differential signatures of normal and episodic events.

    Science.gov (United States)

    Joshi, Manish; Khan, Arshad; Anand, S; Sapra, B K

    2016-01-01

    The effect of fireworks on the aerosol number characteristics of atmosphere was studied for an urban mega city. Measurements were made at 50 m height to assess the local changes around the festival days. Apart from the increase in total number concentration and characteristic accumulation mode, short-term increase of ultrafine particle concentration was noted. Total number concentration varies an order of magnitude during the measurement period in which peak occurs at a frequency of approximately one per day. On integral scale, it seems not possible to distinguish an episodic (e.g. firework bursting induced aerosol emission) and a normal (ambient atmospheric changes) event. However these events could be differentiated on the basis of size evolution analysis around number concentration peaks. The results are discussed relative to past studies and inferences are drawn towards aerosol signatures of firework bursting. The short-term burst in ultrafine particle concentration can pose an inhalation hazard. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Load relaxation behavior of ultra-fine grained Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Y.G.; Kim, J.H.; Lee, C.S. [Dept. of Materials Science and Engineering, Pohang Univ. of Science and Technology, Pohang (Korea); Shin, D.H. [Dept. of Metallurgy and Materials Science, Hanyang Univ., Ansan, Gyeonggi-do (Korea); Semiatin, S.L. [Air Force Research Lab., Materials and Mfg. Directorate Wright-Patterson AFB, OH (United States)

    2005-07-01

    In this study, superplastic deformation behavior of ultrafine-grained Ti-6Al-4V alloy was investigated on the basis of the inelastic deformation theory which consists of grain matrix deformation and grain boundary sliding. Specimens with coarse equiaxed grains (11 {mu}m in diameter) were significantly refined ({approx}0.3 {mu}m in diameter) with high angle boundaries after 4 times of isothermal equal channel angular (ECA) pressing at 600 C. Load relaxation test was performed at 600{proportional_to}700 C to enlighten the deformation mechanisms operating at specific temperature and to find optimum superplastic forming conditions for ultrafine-grained structures. Main efforts were devoted to analyze quantitatively the relative amount of each deformation mode, i.e., dislocation glide and grain boundary sliding operating at specific temperature. (orig.)

  1. Tensile behavior of a TRIP-aided ultra-fine grained steel studied by neutron diffraction

    International Nuclear Information System (INIS)

    Asoo, Kazuya; Tomota, Yo; Harjo, Stefanus; Okitsu, Yoshitaka

    2011-01-01

    Tensile behavior of a nano-TRIP steel with 0.4 μm grain size showing tensile strength of 1326 MPa and total elongation of 23% was studied under in situ neutron diffraction. In spite of ultrafine grained structure, this steel realized a high work-hardening leading to a sufficient amount of uniform elongation. In the beginning of tensile deformation, Lueders band appeared similarly to many ultrafine grained materials. The stress induced martensitic transformation was found to occur during the Lueders deformation. A double-peak fitting was applied to the overlapped neutron diffraction profile for martensite and ferrite and then the stress partitioning behavior among ferrite, retained austenite and martensite were tracked during tensile deformation, revealing that the work-hardening after Lueders deformation was caused by higher load sharing of deformation induced martensite. (author)

  2. THE LATTICE PARAMETERS AND RESIDUAL STRESSES IN BULK NANOCRYSTALLINE AND ULTRAFINE-GRAINED TITANIUM

    Directory of Open Access Journals (Sweden)

    Yu. M. Plotnikova

    2017-05-01

    Full Text Available Lattice parameters and residual stresses in the bulk nanocrystalline/ultrafine-grained titanium were studied by X-ray diffraction methods. The investigated samples were prepared using the method of the cryomechanical grain structure fragmentation with multiple rolling at the temperature of liquid nitrogen to the true strain value |e| = 3. Phasic change of the a and c parameters has been found with increasing degree of cryoreduction. This change was stronger for the parameter a. The observed change parameters associated with a relative slip and twinning activity (initial cryo-reduction stage as well as the formation of the nanocrystalline state (at higher degree of deformation. The most likely source of residual stresses arising in titanium at cryorolling is heterogeneous plastic deformation. The production of nanocrystalline / ultrafine-grained titanium using cryomechanical grain fragmentation method is accompanied by the formation of uniform compressive residual stresses in the informative deformable layer of billet.

  3. Study on ultra-fine w-EDM with on-machine measurement-assisted

    International Nuclear Information System (INIS)

    Chen Shuntong; Yang Hongye

    2011-01-01

    The purpose of this study was to develop the on-machine measurement techniques so as to precisely fabricate micro intricate part using ultra-fine w-EDM. The measurement-assisted approach which employs an automatic optical inspection (AOI) is incorporated to ultra-fine w-EDM process to on-machine detect the machining error for next re-machining. The AOI acquires the image through a high resolution CCD device from the contour of the workpiece after roughing in order to further process and recognize the image for determining the residual. This facilitates the on-machine error detection and compensation re-machining. The micro workpiece and electrode are not repositioned during machining. A fabrication for a micro probe of 30-μm diameter is rapidly machined and verified successfully. Based on the proposed technique, on-machine measurement with AOI has been realized satisfactorily.

  4. Principle and equipment of polymer melt differential electrospinning preparing ultrafine fiber

    International Nuclear Information System (INIS)

    Weimin, Yang; Haoyi, Li

    2014-01-01

    Two methods preparing polymer ultrafine fiber have been developed: solution electrospinning and melt electrospinning, among which, solution electrospinning is much simpler to realize in lab or industry. More than 100 institutions have made endeavors to research it and more than 30 thousand papers have been published. However, its industrialization was restricted in some extend because of existence of toxic solvent and low strength caused by small pores. Solventless melt electrospinning is environment friendly, but high melt viscosity, thick fiber diameter, low yield and complex equipment lead to less research on it. Aiming to solving the shortage of traditional needle nozzle equipment, we first proposed a melt differential electrospinning method preparing ultrafine fiber, through which fiber smaller than imicrometer can be produced and a yield of 10-20g/h can be achieved by a needleless nozzle. Further more, principle and equipment of melt differential electrospinning are introduced

  5. Preparation of an ultra-fine, slightly dispersed silver iodide aerosol

    International Nuclear Information System (INIS)

    Poc, Marie-Martine

    1973-01-01

    A silver iodide aerosol was prepared under clean conditions. The method was to react iodine vapor with a silver aerosol in an inert dry atmosphere and in darkness. Great care was taken to avoid contamination from atmosphere air. The ice nucleating properties of the ultrafine AgI aerosol obtained were studied in a cloud mixing chamber: the aerosol was found to be strangely inactive. (author) [fr

  6. Factors influencing creep flow and ductility in ultrafine-grained metals

    Czech Academy of Sciences Publication Activity Database

    Sklenička, Václav; Dvořák, Jiří; Král, Petr; Svoboda, Milan; Kvapilová, Marie; Langdon, T. G.

    2012-01-01

    Roč. 558, DEC (2012), s. 403-411 ISSN 0921-5093 R&D Projects: GA ČR(CZ) GAP108/11/2260; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : creep * ductility * equal-channel angular pressing * ultrafine-grained material Subject RIV: JG - Metallurgy Impact factor: 2.108, year: 2012

  7. Effect of flow characteristics on ultrafine particle emissions from range hoods.

    Science.gov (United States)

    Tseng, Li-Ching; Chen, Chih-Chieh

    2013-08-01

    In order to understand the physical mechanisms of the production of nanometer-sized particulate generated from cooking oils, the ventilation of kitchen hoods was studied by determining the particle concentration, particle size distribution, particle dimensions, and hood's flow characteristics under several cooking scenarios. This research varied the temperature of the frying operation on one cooking operation, with three kinds of commercial cooking oils including soybean oil, olive oil, and sunflower oil. The variations of particle concentration and size distributions with the elevated cooking oil temperatures were presented. The particle concentration increases as a function of temperature. For oil temperatures ranging between 180°C and 210°C, a 5°C increase in temperature increased the number concentration of ultrafine particles by 20-50%. The maximum concentration of ultrafine particles was found to be approximately 6 × 10(6) particles per cm(3) at 260°C. Flow visualization techniques and particle distribution measurement were performed for two types of hood designs, a wall-mounted range hood and an island hood, at a suction flow rate of 15 m(3) min(-1). The flow visualization results showed that different configurations of kitchen hoods induce different aerodynamic characteristics. By comparing the results of flow visualizations and nanoparticle measurements, it was found that the areas with large-scale turbulent vortices are more prone to dispersion of ultrafine particle leakage because of the complex interaction between the shear layers and the suction movement that results from turbulent dispersion. We conclude that the evolution of ultrafine particle concentration fluctuations is strongly affected by the location of the hood, which can alter the aerodynamic features. We suggest that there is a correlation between flow characteristics and amount of contaminant leakage. This provides a comprehensive strategy to evaluate the effectiveness of kitchen hoods

  8. Photochemical synthesis of ultrafine organosilicon particles from trimethyl(2-propynyloxy)silane and carbon disulfide

    Czech Academy of Sciences Publication Activity Database

    Morita, H.; Nozawa, R.; Bastl, Zdeněk; Šubrt, Jan; Pola, Josef

    2006-01-01

    Roč. 179, 1-2 (2006), s. 142-148 ISSN 1010-6030 Grant - others:MEXT(JP) 767/15085203 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40320502; CEZ:AV0Z40720504 Keywords : ultrafine particles * photo-polymerization * trimethyl(2-propynyloxy)silane * carbon disulfide Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.098, year: 2006

  9. Biokinetics of ultrafine gold nanoparticles (AuNPs) relating to redistribution and urinary excretion: a long-term in vivo study.

    Science.gov (United States)

    Naz, Farhat; Koul, Veena; Srivastava, Amita; Gupta, Yogendra Kumar; Dinda, Amit Kumar

    2016-09-01

    Gold nanoparticles (AuNPs) of ultrafine size have drawn attention for their use in drug delivery systems. Tissue toxicity may be an issue when AuNPs are used for such applications. We investigated the long-term biokinetics (90 d), redistribution, and urinary excretion of three different-sized (2 ± 0.5 nm, 5 ± 1 nm, and 10 ± 2 nm) AuNPs after a single intravenous (i.v.) administration of 1250 µg/kg dose in mice. ICP-AES analysis of lungs, liver, spleen, heart, kidney, brain, blood, and urine revealed highest accumulation of gold in spleen around 15 d after injection. A low concentration was detected in brain after 1 d without any residual AuNPs after 30 d. Ultrastructural study of brain tissue also showed few AuNPs in lysosome with no changes in cellular architecture. Renal retention of AuNPs was limited indicating low nephrotoxic potential. AuNPs were detectable in urine till 30 d after single injection indicating slow excretion from the body. No evidence of significant toxicity was observed in hemogram, serum biochemistry, and tissue histology. No mortality, changes in behavior, hair color, weight, and food intake was observed as compared to control mice. Therefore, we conclude that the ultrafine AuNPs are predominantly excreted in urine without any systemic toxicity following i.v. administration and are hence safe for use in drug delivery systems.

  10. Biosorption of Metals from Multi-Component Bacterial Solutions

    CERN Document Server

    Tsertsvadze, L A; Petriashvili, Sh G; Chutkerashvili, D G; Kirkesali, E I; Frontasyeva, M V; Pavlov, S S; Gundorina, S F

    2002-01-01

    The method of extraction of metals from industrial solutions by means of economical and easy to apply biosorbents in subtropics such as products of tea manufacturing, moss, microorganisms is described. The multi-component solutions obtained in the process of leaching of ores, rocks and industrial wastes by peat suspension were used in the experiments. The element composition of sorbent biomass and solutions was investigated by epithermal neutron activation analysis and by atomic absorption spectrometry. The results obtained evidence that the used biosorbents are applicable for extraction of the whole set of heavy metals and actinides (U, Th, Cu, Mn, Fe, Pb, Li, Rb, Sr, Cd, As, Co and others) from industrial solutions.

  11. Efficiency in chemistry: from hydrogen autotransfer to multicomponent catalysis.

    Science.gov (United States)

    Alonso, Francisco; Foubelo, Francisco; González-Gómez, José C; Martínez, Ricardo; Ramón, Diego J; Riente, Paola; Yus, Miguel

    2010-08-01

    A hydrogen autotransfer reaction has been applied to the α-alkylation of ketones, with primary alcohols as the electrophilic component, either under homogeneous (using a Ru complex as catalyst) or under heterogeneous (using Ni nanoparticles) conditions. This process is both very efficient (concerning atom economy) and ecologically friendly (water as the only by-product generated). On the other hand, three multicomponent reactions, namely, the Strecker reaction (without any catalyst), the aza-Sakurai process (catalyzed by ferrite), and the addition of in situ generated Zn enolates to chiral sulfinylimines (catalyzed by Cu), have proven to be very efficient in the generation of a diversity of polyfunctionalized molecules.

  12. Liquid chromatographic determination of acetaminophen in multicomponent analgesic tablets.

    Science.gov (United States)

    Krieger, D J

    1984-01-01

    A simple, rapid LC method is presented for the separation and determination of acetaminophen in analgesic preparations containing up to 6 additional active components. The method uses a C18 reverse phase column, methanol-0.75% acetic acid (1 + 3) mobile phase, and photometric detection in the ultraviolet region. Acetaminophen was effectively separated from chlorpheniramine maleate, phenylephrine hydrochloride, caffeine, salicylamide, aspirin, and phenacetin, as well as from salicylic acid, a degradation product of aspirin. Typical chromatograms of the separation of acetaminophen from the above compounds in synthetic mixture and in commercial multicomponent analgesic preparations are presented, along with reproducibility and recovery data.

  13. Biochemical Reconstitution and Characterization of Multicomponent Drug Efflux Transporters.

    Science.gov (United States)

    Picard, Martin; Tikhonova, Elena B; Broutin, Isabelle; Lu, Shuo; Verchère, Alice; Zgurskaya, Helen I

    2018-01-01

    Efflux pumps are the major determinants in bacterial multidrug resistance. In Gram-negative bacteria, efflux transporters are organized as macromolecular tripartite machineries that span the two-membrane cell envelope of the bacterium. Biochemical data on purified proteins are essential to draw a mechanistic picture of this highly dynamical, multicomponent, efflux system. We describe protocols for the reconstitution and the in vitro study of transporters belonging to RND and ABC superfamilies: the AcrAB-TolC and MacAB-TolC efflux systems from Escherichia coli and the MexAB-OprM efflux pump from Pseudomonas aeruginosa.

  14. Production of ultrafine zinc powder from wastes containing zinc by electrowinning in alkaline solution

    Directory of Open Access Journals (Sweden)

    Zhao Youcai

    2013-12-01

    Full Text Available Production of ultrafine zinc powder from industrial wastes by electrowinning in alkaline solution was studied. Stainless steel and magnesium electrodes were used as anode and cathode, respectively. Morphology, size distribution and composition of the Zn particles were characterized by Scanning Electron Microscopy, Laser Particle Size Analyzer, and Inductive Coupled Plasma Emission Spectrometer. The required composition of the electrolyte for ultrafine particles was found to be 25-35 g/L Zn, 200-220 g/L NaOH and 20-40 mg/L Pb. The optimal conditions were a current density of 1000-1200 A/m² and an electrolyte temperature of 30-40 °C. The results indicated that the lead additive exerted a beneficial effect on the refining of the particles, by increasing the cathodic polarization. Through this study, ultrafine zinc powder with a size distribution of around 10 μm could be produced, and considerably high current efficiencies (97-99 % were obtained.

  15. Biodegradable Behaviors of Ultrafine-Grained ZE41A Magnesium Alloy in DMEM Solution

    Directory of Open Access Journals (Sweden)

    Jinghua Jiang

    2015-12-01

    Full Text Available The main limitation to the clinical application of magnesium alloys is their too-fast degradation rate in the physiological environment. Bio-corrosion behaviors of the ZE41A magnesium alloy processed by multi-pass equal channel angular pressing (ECAP were investigated in Dulbecco's Modified Eagle Medium (DMEM solution, in order to tailor the effect of grain ultrafining on the biodegradation rate of the alloy implant. Hydrogen evolution tests indicated that a large number of ECAP passes decreased the stable corrosion rate of the alloy after the initial incubation period. Potentiodynamic polarization curves showed that more ECAP passes made the corrosion potential nobler and the corrosion tendency lower. Corroded surfaces of the ECAPed alloy indicated a higher resistance toward localized corrosion due to the homogeneous redistribution of broken second phases on the ultrafine-grained Mg matrix. It suggests that grain ultrafining can decrease the biodegradable rate of the magnesium alloy-containing rare-earth elements and tailor the lifetime of the biodegradable material.

  16. Analysis of Fatigue and Wear Behaviour in Ultrafine Grained Connecting Rods

    Directory of Open Access Journals (Sweden)

    Rodrigo Luri

    2017-07-01

    Full Text Available Over the last few years there has been an increasing interest in the study and development of processes that make it possible to obtain ultra-fine grained materials. Although there exists a large number of published works related to the improvement of the mechanical properties in these materials, there are only a few studies that analyse their in-service behaviour (fatigue and wear. In order to bridge the gap, in this present work, the fatigue and wear results obtained for connecting rods manufactured by using two different aluminium alloys (AA5754 and AA5083 previously deformed by severe plastic deformation (SPD, using Equal Channel Angular Pressing (ECAP, in order to obtain the ultrafine grain size in the processed materials are shown. For both aluminium alloys, two initial states were studied: annealed and ECAPed. The connecting rods were manufactured from the previously processed materials by using isothermal forging. Fatigue and wear experiments were carried out in order to characterize the in-service behaviour of the components. A comparative study of the results was made for both initial states of the materials. Furthermore, Finite Element Modelling (FEM simulations were used in order to compare experimental results with those obtained from simulations. In addition, dimensional wear coefficients were found for each of the aluminium alloys and initial deformation states. This research work aims to progress the knowledge of the behaviour of components manufactured from ultrafine grain materials.

  17. Enhanced radiation tolerance of ultrafine grained Fe–Cr–Ni alloy

    International Nuclear Information System (INIS)

    Sun, C.; Yu, K.Y.; Lee, J.H.; Liu, Y.; Wang, H.; Shao, L.; Maloy, S.A.; Hartwig, K.T.; Zhang, X.

    2012-01-01

    Highlights: ► Ultrafine grained Fe-Cr-Ni alloy was processed by equal channel angular pressing technique. ► The overall Helium bubble density and dislocation loop density were reduced by grain refinement. ► The ultrafine grained microstructure alleviated radiation-induced hardening. - Abstract: The evolutions of microstructure and mechanical properties of Fe–14Cr–16Ni (wt.%) alloy subjected to Helium ion irradiations were investigated. Equal channel angular pressing (ECAP) process was used to significantly reduce the average grain size from 700 μm to 400 nm. At a peak fluence level of 5.5 displacement per atom (dpa), helium bubbles, 0.5–2 nm in diameter, were observed in both coarse-grained (CG) and ultrafine grained (UFG) alloy. The density of He bubbles, dislocation loops, as well as radiation hardening were reduced in the UFG Fe–Cr–Ni alloy comparing to those in its CG counterpart. The results imply that radiation tolerance in bulk metals can be effectively enhanced by refinement of microstructures.

  18. Direct Electrospinning of Ultrafine Fibers with Interconnected Macropores Enabled by in Situ Mixing Microfluidics.

    Science.gov (United States)

    Liu, Wanjun; Zhu, Lei; Huang, Chen; Jin, Xiangyu

    2016-12-21

    Porous ultrafine fibers are of great importance to various applications. Herein, we report a method to directly fabricate macro-porous ultrafine fibers by an in situ mixing microfluidics which allows for the simultaneous electrospinning of solution immediately after mixing. The formation mechanism of macro-pores should be attributed to the incomplete mixing coupled with nonsolvent-induced phase separation, which was elucidated by systematical investigation of various solvent systems and mixing solvents. The diameter of the macro-porous fibers can be tuned from 1.80 ± 0.40 to 6.75 ± 0.48 μm by adjusting the solution concentration and the feeding rate of mixing solvent. The results indicated that macro-porous fibers exhibited higher specific surface area (48.66 ± 8.30 m 2 g -1 ), larger pore size (116.73 nm) and pore volume (0.169 ± 0.007 cm 3 g -1 ) than conventional electrospun porous fibers, enabling the high oil absorption capacities of 95.68, 57.98, and 34.82 g g -1 for silicon oil, motor oil, and peanut oil, respectively. Our method has greatly expanded the solution scope for electrospinning from stable solution systems to unstable or substable solution systems, thus providing intriguing opportunities for the investigation and fabrication of heterogeneous fibers by in situ mixing of various immiscible solvents/solutions. Our findings can serve as guidelines for the electrospinning of ultrafine fibers with interconnected macro-pores (>50 nm).

  19. Advancing nanograined/ultrafine-grained structures for metal implant technology: Interplay between grooving of nano/ultrafine grains and cellular response

    International Nuclear Information System (INIS)

    Venkatsurya, P.K.C; Thein-Han, W.W.; Misra, R.D.K.; Somani, M.C.; Karjalainen, L.P.

    2010-01-01

    Nanograined/ultrafine-grained (NG/UFG) metals provide surfaces that are different from conventional coarse-grained polycrystalline metals because of the high fraction of grain boundaries. In the context of osseointegration of metal implants, grooving of nanograins/ultrafine grains by electrochemical grooving is a potential approach to increase the biomechanical interlocking and anchorage with consequent enhancement of cellular response. The primary objective of the research described here is to advance science and technology of metal implants by making a relative comparison of osteoblast response of grain boundary grooved and planar NG/UFG surfaces. The NG/UFG substrates were obtained using an ingenious concept of controlled phase reversion and the grain boundaries were electrochemically treated to induce grooving of large fraction of grain boundaries of NG/UFG substrate. Experiments on the effect of grooving of grain boundaries of NG/UFG metal indicated that cell attachment, proliferation, viability, morphology, and spread are favorably modulated and significantly different from planar (non-grooved) NG/UFG substrates. Furthermore, immunofluorescence studies demonstrated stronger vinculin signals associated with actin stress fibers in the outer regions of the cells and cellular extensions on electrochemically grooved NG/UFG substrate. These observations are indicative of accelerated response of cell-substrate interaction and activity. The differences in the cellular response of planar and grain boundary grooved NG/UFG surface are attributed to favorable surface topography that accelerates the cellular activity.

  20. The multicomponent (2+1)-dimensional Glachette–Johnson (GJ) equation hierarchy and its super-integrable coupling system

    International Nuclear Information System (INIS)

    Yu Fajun; Zhang Hongqing

    2008-01-01

    This paper presents a set of multicomponent matrix Lie algebra, which is used to construct a new loop algebra à M . By using the Tu scheme, a Liouville integrable multicomponent equation hierarchy is generated, which possesses the Hamiltonian structure. As its reduction cases, the multicomponent (2+1)-dimensional Glachette–Johnson (GJ) hierarchy is given. Finally, the super-integrable coupling system of multicomponent (2+1)-dimensional GJ hierarchy is established through enlarging the spectral problem

  1. Increased ultrafine particles and carbon monoxide concentrations are associated with asthma exacerbation among urban children

    Science.gov (United States)

    Evans, Kristin A.; Halterman, Jill S.; Hopke, Philip K.; Fagnano, Maria; Rich, David Q.

    2014-01-01

    Objectives Increased air pollutant concentrations have been linked to several asthma-related outcomes in children, including respiratory symptoms, medication use, and hospital visits. However, few studies have examined effects of ultrafine particles in a pediatric population. Our primary objective was to examine the effects of ambient concentrations of ultrafine particles on asthma exacerbation among urban children and determine whether consistent treatment with inhaled corticosteroids could attenuate these effects. We also explored the relationship between asthma exacerbation and ambient concentrations of accumulation mode particles, fine particles (≤ 2.5 micrograms [μm]; PM2.5), carbon monoxide, sulfur dioxide, and ozone. We hypothesized that increased 1 to 7 day concentrations of ultrafine particles and other pollutants would be associated with increases in the relative odds of an asthma exacerbation, but that this increase in risk would be attenuated among children receiving school-based corticosteroid therapy. Methods We conducted a pilot study using data from 3–10 year-old children participating in the School-Based Asthma Therapy trial. Using a time-stratified case-crossover design and conditional logistic regression, we estimated the relative odds of a pediatric asthma visit treated with prednisone (n=96 visits among 74 children) associated with increased pollutant concentrations in the previous 7 days. We re-ran these analyses separately for children receiving medications through the school-based intervention and children in a usual care control group. Results Interquartile range increases in ultrafine particles and carbon monoxide concentrations in the previous 7 days were associated with increases in the relative odds of a pediatric asthma visit, with the largest increases observed for 4-day mean ultrafine particles (interquartile range=2088 p/cm3; OR=1.27; 95% CI=0.90–1.79) and 7-day mean carbon monoxide (interquartile range=0.17 ppm; OR=1.63; 95

  2. Ultrasonic spectrum for particle concentration measurement in multicomponent suspensions

    International Nuclear Information System (INIS)

    Zhan, Xiaobin; Yang, Yili; Liang, Jian; Shi, Tielin; Li, Xiwen; Jiang, Shulan

    2016-01-01

    This paper studies the feasibility of applying the ultrasonic spectrum technique to the measurement of particle concentrations in multicomponent suspensions. A combination of the kernel partial least squares (KPLS) model and the interval selection methods is implemented to build the relationship between the ultrasonic spectra of the first reflected pulses and the particle concentrations. First of all, the interval selection methods are used to select optimal spectral interval(s) from full spectra. Then, the KPLS models with optimal spectral interval(s) are tuned, built and evaluated to obtain the optimal model. Finally, the optimal KPLS model is employed to measure the particle concentrations in the mixing process and its online prediction ability is evaluated. In comparison with the linear partial least squares (PLS) models, the optimal KPLS model shows the best performance. The results demonstrate that particle concentrations in multicomponent suspensions can be measured online by the ultrasonic spectrum technique, and the KPLS model with optimal spectral interval(s) shows the superiority in model calibration. (paper)

  3. Issues of structure formation of multi-component construction materials

    Directory of Open Access Journals (Sweden)

    Sidorenko Yulia

    2017-01-01

    Full Text Available Growing volumes of construction result in the rising demand for high-quality wall materials and products, growing relevance of availability of resource and raw-material base of natural and industrial products for the construction industry. Structural, physical and mechanical qualities of these products can be improved through systematical selection of compositions based on natural and raw materials, including nano-scale products. The goal of this paper is to provide rationale for structure formation mechanisms of multicomponent materials (silica-lime, silicate, cement materials, with the possibility of using nano-scale products in their production. The primary mechanism of directed structure formation at the interface boundaries of binders are nano- and ultra-disperse particles with high absorption and adhesion properties, which are primarily intended to strengthen the contact area (one of the key structural units of multicomponent binders. The knowledge of genesis, chemical, mineralogical, and phase compositions, as well as specific features of formation of nano-technological raw materials, enables optimization of construction product properties. Using the small-angle neutron scattering method, we identified granulometric and surface properties of a series of nano-technological products (binary and sludge and materials where such products are used, which enabled us to design optimal mixture compositions and parameters of pressing operations.

  4. Statistical physics of multicomponent alloys using KKR-CPA

    Science.gov (United States)

    Khan, Suffian N.; Staunton, J. B.; Stocks, G. M.

    2016-02-01

    We apply variational principles from statistical physics and the Landau theory of phase transitions to multicomponent alloys using the multiple-scattering theory of Korringa-Kohn-Rostoker (KKR) and the coherent potential approximation (CPA). This theory is a multicomponent generalization of the S(2 ) theory of binary alloys developed by G. M. Stocks, J. B. Staunton, D. D. Johnson, and others. It is highly relevant to the chemical phase stability of high-entropy alloys as it predicts the kind and size of finite-temperature chemical fluctuations. In doing so, it includes effects of rearranging charge and other electronics due to changing site occupancies. When chemical fluctuations grow without bound, an absolute instability occurs and a second-order order-disorder phase transition may be inferred. The S(2 ) theory is predicated on the fluctuation-dissipation theorem; thus we derive the linear response of the CPA medium to perturbations in site-dependent chemical potentials in great detail. The theory lends itself to a natural interpretation in terms of competing effects: entropy driving disorder and favorable pair interactions driving atomic ordering. To further clarify interpretation, we present results for representative ternary alloys CuAgAu, NiPdPt, RhPdAg, and CoNiCu within a frozen charge (or band-only) approximation. These results include the so-called Onsager mean-field correction that extends the temperature range for which the theory is valid.

  5. Field experiment on multicomponent ion exchange in a sandy aquifer

    International Nuclear Information System (INIS)

    Bjerg, P.L.; Christensen, T.H.

    1990-01-01

    A field experiment is performed in a sandy aquifer in order to study ion exchange processes and multicomponent solute transport modeling. An injection of groundwater spiked with sodium and potassium chloride was performed over a continuous period of 37 days. The plume is monitored by sampling 350 filters in a spatial grid. The sampling aims at establishing compound (calcium, magnesium, potassium, sodium, chloride) breakthrough curves at various filters 15 to 100 m from the point of injection and areal distribution maps at various cross sections from 0 to 200 m from the point of injection. A three-dimensional multicomponent solute transport model will be used to model the field experiments. The chemical model includes cation exchange, precipitation, dissolution, complexation, ionic strength and the carbonate system. Preliminary results from plume monitoring show that the plume migration is relatively well controlled considering the scale and conditions of the experiment. The transverse dispersion is small causing less dilution than expected. The ion exchange processes have an important influence on the plume composition. Retardation of the injected ions is substantial, especially for potassium. Calcium exhibits a substantial peak following chloride due to release from the ion exchange sites on the sediment. (Author) (8 refs., 5 figs., tab.)

  6. A microscopic study on the corrosion fatigue of ultra-fine grained and conventional Al–Mg alloy

    International Nuclear Information System (INIS)

    Sharma, Mala M.; Tomedi, Josh D.; Parks, Jeffery M.

    2015-01-01

    Highlights: • Corrosion fatigue was investigated for an ultra-fine grained and conventional 5083 alloy. • Pit initiation, pit location and crack propagation were investigated. • In air, the ultra-fine grained alloy had superior fatigue performance compared to conventional 5083 alloy. • At low maximum stress, the ultra-fine grained alloy is more susceptible to fatigue by pitting. • At high maximum stress, slip enhanced dissolution is the dominant mechanism or the ultra-fine grained alloy. - Abstract: The corrosion behavior of a nanocrystalline (NC)/ultrafine grained (UFG) Al–Mg based alloy was investigated and compared to its conventional counterpart 5083(H111). The corrosion fatigue (CF) was studied with respect to pit initiation, pit location and crack propagation as a function of environment. Scanning electron microscopy (SEM) with EDS was used to analyze the fracture surface of the failed specimen with respect to pitting characteristics, crack propagation and corrosion product. Load vs. cycles to failure was measured and S/N curves were generated for the UFG Al–Mg based alloy and the conventional counterpart 5083 in air and seawater

  7. Effectiveness of the Top-Down Nanotechnology in the Production of Ultrafine Cement (~220 nm

    Directory of Open Access Journals (Sweden)

    Byung-Wan Jo

    2014-01-01

    Full Text Available The present investigation is dealing with the communition of the cement particle to the ultrafine level (~220 nm utilizing the bead milling process, which is considered as a top-down nanotechnology. During the grinding of the cement particle, the effect of various parameters such as grinding time (1–6 h and grinding agent (methanol and ethanol on the production of the ultrafine cement has also been investigated. Performance of newly produced ultrafine cement is elucidated by the chemical composition, particle size distribution, and SEM and XRD analyses. Based on the particle size distribution of the newly produced ultrafine cement, it was assessed that the size of the cement particle decreases efficiently with increase in grinding time. Additionally, it is optimized that the bead milling process is able to produce 90% of the cement particle <350 nm and 50% of the cement particle < 220 nm, respectively, after 6.3 h milling without affecting the chemical phases. Production of the ultrafine cement utilizing this method will promote the construction industries towards the development of smart and sustainable construction materials.

  8. Activation of persulfate by irradiated laterite for removal of fluoroquinolones in multi-component systems.

    Science.gov (United States)

    Kamagate, Mahamadou; Amin Assadi, Aymen; Kone, Tiangoua; Coulibaly, Lacina; Hanna, Khalil

    2018-03-15

    Although several emerging contaminants (e.g. fluoro(quinolones) (FQs)) have been simultaneously detected in environmental systems, there is very limited information on their elimination from contaminated waters in multi-component systems. In this study, removal of three FQs including flumequine (FLU), ciprofloxacin (CIP) and norfloxacin (NOR) were investigated in single and mixture systems, using natural laterite soil and persulfate (PS) under UVA irradiation. Both sorption and oxidation reactions contribute to the removal of FQs from aqueous phase, whereas quenching experiments showed that SO 4 - is mainly responsible for the FQs oxidation. The kinetic rate constants can be ranked as follows: CIP > NOR > FLU, regardless of whether the compound was alone or in mixture. The higher degradation rate constant of CIP relative to those of NOR and FLU could be explained by the high reactivity of SO 4 - radical with cyclopropane-ring containing compounds. Fall in oxidation performance was observed in synthetic wastewater, probably due to sulfate radical scavenging by wastewater components. However, degradation rate constants of CIP in wastewater remains unchanged in mixture systems as compared to single ones. This environmentally friendly remediation technology may appear as a promising way for the removal of fluoroquinolone antibiotics from multi-contaminated waters. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Technology optimization techniques for multicomponent optical band-pass filter manufacturing

    Science.gov (United States)

    Baranov, Yuri P.; Gryaznov, Georgiy M.; Rodionov, Andrey Y.; Obrezkov, Andrey V.; Medvedev, Roman V.; Chivanov, Alexey N.

    2016-04-01

    Narrowband optical devices (like IR-sensing devices, celestial navigation systems, solar-blind UV-systems and many others) are one of the most fast-growing areas in optical manufacturing. However, signal strength in this type of applications is quite low and performance of devices depends on attenuation level of wavelengths out of operating range. Modern detectors (photodiodes, matrix detectors, photomultiplier tubes and others) usually do not have required selectivity or have higher sensitivity to background spectrum at worst. Manufacturing of a single component band-pass filter with high attenuation level of wavelength is resource-intensive task. Sometimes it's not possible to find solution for this problem using existing technologies. Different types of filters have technology variations of transmittance profile shape due to various production factors. At the same time there are multiple tasks with strict requirements for background spectrum attenuation in narrowband optical devices. For example, in solar-blind UV-system wavelengths above 290-300 nm must be attenuated by 180dB. In this paper techniques of multi-component optical band-pass filters assembly from multiple single elements with technology variations of transmittance profile shape for optimal signal-tonoise ratio (SNR) were proposed. Relationships between signal-to-noise ratio and different characteristics of transmittance profile shape were shown. Obtained practical results were in rather good agreement with our calculations.

  10. Ultrafine tungsten as a plasma-facing component in fusion devices: effect of high flux, high fluence low energy helium irradiation

    NARCIS (Netherlands)

    El-Atwani, O.; Gonderman, S.; Efe, M.; De Temmerman, G.; Morgan, T.; Bystrov, K.; D. Klenosky,; Qiu, T.; Allain, J. P.

    2014-01-01

    This work discusses the response of ultrafine-grained tungsten materials to high-flux, high-fluence, low energy pure He irradiation. Ultrafine-grained tungsten samples were exposed in the Pilot-PSI (Westerhout et al 2007 Phys. Scr. T128 18) linear plasma device at the Dutch Institute for Fundamental

  11. Nonlinear processing of a multicomponent communication signal by combination-sensitive neurons in the anuran inferior colliculus.

    Science.gov (United States)

    Lee, Norman; Schrode, Katrina M; Bee, Mark A

    2017-09-01

    Diverse animals communicate using multicomponent signals. How a receiver's central nervous system integrates multiple signal components remains largely unknown. We investigated how female green treefrogs (Hyla cinerea) integrate the multiple spectral components present in male advertisement calls. Typical calls have a bimodal spectrum consisting of formant-like low-frequency (~0.9 kHz) and high-frequency (~2.7 kHz) components that are transduced by different sensory organs in the inner ear. In behavioral experiments, only bimodal calls reliably elicited phonotaxis in no-choice tests, and they were selectively chosen over unimodal calls in two-alternative choice tests. Single neurons in the inferior colliculus of awake, passively listening subjects were classified as combination-insensitive units (27.9%) or combination-sensitive units (72.1%) based on patterns of relative responses to the same bimodal and unimodal calls. Combination-insensitive units responded similarly to the bimodal call and one or both unimodal calls. In contrast, combination-sensitive units exhibited both linear responses (i.e., linear summation) and, more commonly, nonlinear responses (e.g., facilitation, compressive summation, or suppression) to the spectral combination in the bimodal call. These results are consistent with the hypothesis that nonlinearities play potentially critical roles in spectral integration and in the neural processing of multicomponent communication signals.

  12. Second-order perturbations of cosmological fluids: Relativistic effects of pressure, multicomponent, curvature, and rotation

    International Nuclear Information System (INIS)

    Hwang, Jai-chan; Noh, Hyerim

    2007-01-01

    We present general relativistic correction terms appearing in Newton's gravity to the second-order perturbations of cosmological fluids. In our previous work we have shown that to the second-order perturbations, the density and velocity perturbation equations of general relativistic zero-pressure, irrotational, single-component fluid in a spatially flat background coincide exactly with the ones known in Newton's theory without using the gravitational potential. We also have shown the effect of gravitational waves to the second order, and pure general relativistic correction terms appearing in the third-order perturbations. Here, we present results of second-order perturbations relaxing all the assumptions made in our previous works. We derive the general relativistic correction terms arising due to (i) pressure, (ii) multicomponent, (iii) background spatial curvature, and (iv) rotation. In the case of multicomponent zero-pressure, irrotational fluids under the flat background, we effectively do not have relativistic correction terms, thus the relativistic equations expressed in terms of density and velocity perturbations again coincide with the Newtonian ones. In the other three cases we generally have pure general relativistic correction terms. In the case of pressure, the relativistic corrections appear even in the level of background and linear perturbation equations. In the presence of background spatial curvature, or rotation, pure relativistic correction terms directly appear in the Newtonian equations of motion of density and velocity perturbations to the second order; to the linear order, without using the gravitational potential (or metric perturbations), we have relativistic/Newtonian correspondences for density and velocity perturbations of a single-component fluid including the rotation even in the presence of background spatial curvature. In the small-scale limit (far inside the horizon), to the second-order, relativistic equations of density and

  13. Evaluation of multicomponent recombinant vaccines against Actinobacillus pleuropneumoniae in mice

    Directory of Open Access Journals (Sweden)

    Shao Meili

    2010-09-01

    Full Text Available Abstract Background Porcine contagious pleuropneumonia (PCP is a highly contagious disease that is caused by Actinobacillus pleuropneumoniae (APP and characterized by severe fibrinous necrotizing hemorrhagic pleuropneumonia, which is a severe threat to the swine industry. In addition to APP RTX-toxins I (ApxI, APP RTX-toxin II (ApxII, APP RTX-toxin III (ApxIII and Outer membrane protein (OMP, there may be other useful antigens that can contribute to protection. In the development of an efficacious vaccine against APP, the immunogenicities of multicomponent recombinant subunit vaccines were evaluated. Methods Six major virulent factor genes of APP, i.e., apxI, apxII, apxIII, APP RTX-toxins IV (apxIV, omp and type 4 fimbrial structural (apfa were expressed. BALB/c mice were immunized with recombinant ApxI ( rApxI, recombinant ApxII (rApxII, recombinant ApxIII (rApxIII and recombinant OMP (rOMP (Group I; rApxI, rApxII, rApxIII, recombinant ApxIV (rApxIV, recombinant Apfa (rApfa and rOMP (Group II; APP serotype 1 (APP1 inactivated vaccine (Group III; or phosphate-buffered saline (PBS (Control group, respectively. After the first immunization, mice were subjected to two booster immunizations at 2-week intervals, followed by challenge with APP1 Shope 4074 and APP2 S1536. Results The efficacy of the multicomponent recombinant subunit vaccines was evaluated on the basis of antibody titers, survival rates, lung lesions and indirect immunofluorescence (IIF detection of APP. The antibody level of Group I was significantly higher than those of the other three groups (P P P Conclusion The result indicates that the multicomponent recombinant subunit vaccine composed of rApxI, rApxII, rApxIII and rOMP can provide effective cross-protection against homologous and heterologous APP challenge.

  14. Nuclear microprobe investigation of the penetration of ultrafine zinc oxide into intact and tape-stripped human skin

    Energy Technology Data Exchange (ETDEWEB)

    Szikszai, Z., E-mail: szikszai@atomki.h [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen (Hungary); Kertesz, Zs. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen (Hungary); Bodnar, E. [Department of Dermatology, University of Debrecen, Medical and Health Science Center, Debrecen (Hungary); Major, I. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen (Hungary); Borbiro, I. [Abiol Ltd., Debrecen (Hungary); Kiss, A.Z. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen (Hungary); Hunyadi, J. [Department of Dermatology, University of Debrecen, Medical and Health Science Center, Debrecen (Hungary)

    2010-06-15

    Ultrafine metal oxides, such as titanium dioxide and zinc oxide are widely used in cosmetic and health products like sunscreens. These oxides are potent UV filters and the small particle size makes the product more transparent compared to formulations containing coarser particles. In the present work the penetration of ultrafine zinc oxide into intact and tape-stripped human skin was investigated using nuclear microprobe techniques, such as proton induced X-ray spectroscopy and scanning transmission ion microscopy. Our results indicate that the penetration of ultrafine zinc oxide, in a hydrophobic basis gel with 48 h application time, is limited to the stratum corneum layer of the intact skin. Removing the stratum corneum partially or entirely by tape-stripping did not cause the penetration of the particles into the deeper dermal layers; the zinc particles remained on the surface of the skin.

  15. [Vapor-liquid equilibria for multicomponent organic solvents].

    Science.gov (United States)

    Ishidao, Toru; Ishimatsu, Sumiyo; Hori, Hajime

    2004-09-01

    Most organic solvents used in the workplace are mixed solvents consisting of several components. It is therefore very important to know the equilibrated vapor concentrations in order to control the work environment. In this study, the vapor-liquid equilibrium for multicomponent organic solvents is estimated by introducing the activity coefficients, which are calculated with the UNIFAC (Universal Quasichemical Functional Group Activity Coefficient) model. For two-component solvents, that is, the toluene-methanol and o-xylene-methanol systems, the calculated values of the vapor fraction and the equilibrated vapor concentrations are in good agreement with the reference ones. For three- or four-component solvents that are used as thinners, the calculated values are also generally in good agreement with the reference ones.

  16. Submicron Confocal Raman Microscopy of Optical Holograms in Multicomponent Photopolymers

    Science.gov (United States)

    Kagan, C. R.; Harris, T. D.; Harris, A. L.; Schilling, M. L.

    1998-03-01

    We demonstrate submicron chemical imaging of optical holograms in multicomponent photopolymers using a scanning confocal Raman microscope. Our microscope is sensitive to the submicron, <1 percent concentration variations of the polymeric components that form the refractive index modulation responsible for hologram diffraction. Photopolymers are attractive media for holographic data storage, yet the mechanisms for generating the refractive index modulations responsible for hologram diffraction remain poorly understood. We obtain the first direct chemical evidence showing that these concentration modulations are established both by monomer diffusion and by polymer matrix swelling during hologram writing. Spatial variations in both density and composition contribute to the refractive index modulation. These measurements demonstrate the feasibility of submicron Raman microscopy in chemically imaging photodegradable organic and biological materials.

  17. Fast, Approximate Solutions for 1D Multicomponent Gas Injection Problems

    DEFF Research Database (Denmark)

    Jessen, Kristian; Wang, Yun; Ermakov, Pavel

    2001-01-01

    by the geometry of key tie lines. It has previously been proven that for systems with an arbitrary number of components, the key tie lines can be approximated quite accurately by a sequence of intersecting tie lines. As a result, analytical solutions can be constructed efficiently for problems with constant......This paper presents a new approach for constructing approximate analytical solutions for ID, multicomponent gas displacement problems. The solution to mass conservation equations governing ID dispersion-free flow in which components partition between two equilibrium phases is controlled...... initial and injection compositions (Riemann problems). For fully self-sharpening systems, in which all key tie lines are connected by shocks, the analytical solutions obtained are rigorously accurate, while for systems in which some key tie lines are connected by spreading waves, the analytical solutions...

  18. Energetic Variational Approach to Multi-Component Fluid Flows

    Science.gov (United States)

    Kirshtein, Arkadz; Liu, Chun; Brannick, James

    2017-11-01

    In this talk I will introduce the systematic energetic variational approach for dissipative systems applied to multi-component fluid flows. These variational approaches are motivated by the seminal works of Rayleigh and Onsager. The advantage of this approach is that we have to postulate only energy law and some kinematic relations based on fundamental physical principles. The method gives a clear, quick and consistent way to derive the PDE system. I will compare different approaches to three-component flows using diffusive interface method and discuss their advantages and disadvantages. The diffusive interface method is an approach for modeling interactions among complex substances. The main idea behind this method is to introduce phase field labeling functions in order to model the contact line by smooth change from one type of material to another. The work of Arkadz Kirshtein and Chun Liu is partially supported by NSF Grants DMS-141200 and DMS-1216938.

  19. A green multicomponent synthesis of tocopherol analogues with antiproliferative activities.

    Science.gov (United States)

    Ingold, Mariana; Dapueto, Rosina; Victoria, Sabina; Galliusi, Germán; Batthyàny, Carlos; Bollati-Fogolín, Mariela; Tejedor, David; García-Tellado, Fernando; Padrón, José M; Porcal, Williams; López, Gloria V

    2018-01-01

    A one-pot efficient, practical and eco-friendly synthesis of tocopherol analogues has been developed using water or solvent free conditions via Passerini and Ugi multicomponent reactions. These reactions can be optimized using microwave irradiation or ultrasound as the energy source. Accordingly, a small library of 30 compounds was prepared for biological tests. The evaluation of the antiproliferative activity in the human solid tumor cell lines A549 (lung), HBL-100 (breast), HeLa (cervix), SW1573 (lung), T-47D (breast), and WiDr (colon) provided lead compounds with GI 50 values between 1 and 5 μM. A structure-activity relationship is also discussed. One of the studied compounds comes up as a future candidate for the development of potent tocopherol-mimetic therapeutic agents for cancer. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. Water activity changes of multicomponent food mixture during processing

    Directory of Open Access Journals (Sweden)

    Jiří Štencl

    2004-01-01

    Full Text Available Water activity of multicomponent food mixture was analysed and measured. Samples of dry fermented sausages with two different starter cultures (Pediococcus pentosaceus + Staphylococcus carnosus and Staphylococcus carnosus + Staphylococcus xylosus + Lactobacillus farciminis were tested during ripening (21 days and storing (91 days. The basic raw materials were the same for all samples: lean beef meat, lean pork and pork fat in equal parts, nitrite salt mixture (2.5 %, and sugars (1.0 %. The method used for water activity tests was indirect manometric in a static environment. Moisture content of samples was measured using halogen dryer. The course of water activity and moisture content of sausages was variable during ripening and steady during storage. Diagrams showed gradual decrease of both parameters. Mathematical models of water activity and moisture content for storage of dry fermented sausages were developed and statistically verified. The influence of starter cultures was not significant.

  1. A multi-component evaporation model for beam melting processes

    Science.gov (United States)

    Klassen, Alexander; Forster, Vera E.; Körner, Carolin

    2017-02-01

    In additive manufacturing using laser or electron beam melting technologies, evaporation losses and changes in chemical composition are known issues when processing alloys with volatile elements. In this paper, a recently described numerical model based on a two-dimensional free surface lattice Boltzmann method is further developed to incorporate the effects of multi-component evaporation. The model takes into account the local melt pool composition during heating and fusion of metal powder. For validation, the titanium alloy Ti-6Al-4V is melted by selective electron beam melting and analysed using mass loss measurements and high-resolution microprobe imaging. Numerically determined evaporation losses and spatial distributions of aluminium compare well with experimental data. Predictions of the melt pool formation in bulk samples provide insight into the competition between the loss of volatile alloying elements from the irradiated surface and their advective redistribution within the molten region.

  2. "Stamp-off" to micropattern sparse, multicomponent features.

    Science.gov (United States)

    Desai, Ravi A; Rodriguez, Natalia M; Chen, Christopher S

    2014-01-01

    Spatially patterned subtractive de-inking, a process we term "stamp-off," provides a simple method to generate sparse, multicomponent protein micropatterns. It has been applied to control cell adhesion, study adhesion biology, as well as to micropattern fragile surfaces. This technique can also readily be applied to study nanoscale interactions between cell membrane receptors and surface-immobilized ligands. It is based on conventional microcontact printing and as such requires the same reagents, including photolithographically defined masters, a spin-coater, poly(dimethyl siloxane) (PDMS), and conventional cell culture reagents such as glass coverslips and adhesive proteins. Stamp-off is conceptually simplified into three steps: (1) generation of an appropriate cell culture substrate, PDMS-coated glass, (2) micropatterning with stamp-off, and (3) cell deposition. After elaborating each of these three methods, we discuss limitations of the technique and its applications. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Biosorption of metals from multi-component bacterial solution

    International Nuclear Information System (INIS)

    Tsertsvadze, L.A.; Dzadzamiya, T.D.; Petriashvili, Sh.G.; Chutkerashvili, D.G.; Kirkesali, E.I.; Frontas'eva, M.V.; Pavlov, S.S.; Gundorina, S.F.

    2002-01-01

    The method of extraction of metals from industrial solutions by means of economical and easy to apply biosorbents in subtropics such as products of tea manufacturing, moss, microorganisms is described. The multi-component solutions obtained in the process of leaching of ores, rocks and industrial wastes by peat suspension were used in the experiments. The element composition of sorbent biomass and solutions was investigated by epithermal neutron activation analysis and by atomic absorption spectrometry. The results obtained evidence that the used biosorbents are applicable for extraction of the whole set of heavy metals and actinides (U, Th, Cu, Mn, Fe, Pb, Li, Rb, Sr, Cd, As, Co and others ) from industrial solutions. (author)

  4. Soot, organics, and ultrafine ash from air- and oxy-fired coal combustion

    KAUST Repository

    Andersen, Myrrha E.

    2016-10-19

    Pulverized bituminous coal was burned in a 10. W externally heated entrained flow furnace under air-combustion and three oxy-combustion inlet oxygen conditions (28, 32, and 36%). Experiments were designed to produce flames with practically relevant stoichiometric ratios (SR. =1.2-1.4) and constant residence times (2.3. s). Size-classified fly ash samples were collected, and measurements focused on the soot, elemental carbon (EC), and organic carbon (OC) composition of the total and ultrafine (<0.6. μm) fly ash. Results indicate that although the total fly ash carbon, as measured by loss on ignition, was always acceptably low (<2%) with all three oxy-combustion conditions lower than air-combustion, the ultrafine fly ash for both air-fired and oxy-fired combustion conditions consists primarily of carbonaceous material (50-95%). Carbonaceous components on particles <0.6. μm measured by a thermal optical method showed that large fractions (52-93%) consisted of OC rather than EC, as expected. This observation was supported by thermogravimetric analysis indicating that for the air, 28% oxy, and 32% oxy conditions, 14-71% of this material may be OC volatilizing between 100. C and 550. C with the remaining 29-86% being EC/soot. However, for the 36% oxy condition, OC may comprise over 90% of the ultrafine carbon with a much smaller EC/soot contribution. These data were interpreted by considering the effects of oxy-combustion on flame attachment, ignition delay, and soot oxidation of a bituminous coal, and the effects of these processes on OC and EC emissions. Flame aerodynamics and inlet oxidant composition may influence emissions of organic hazardous air pollutants (HAPs) from a bituminous coal. During oxy-coal combustion, judicious control of inlet oxygen concentration and placement may be used to minimize organic HAP and soot emissions.

  5. A study of manufacturing tubes with nano/ultrafine grain structure by stagger spinning

    International Nuclear Information System (INIS)

    Xia, Qinxiang; Xiao, Gangfeng; Long, Hui; Cheng, Xiuquan; Yang, Baojian

    2014-01-01

    Highlights: • Proposing a method of manufacturing tubes with nano/ultrafine crystal. • Obtaining the refined ferritic grains with an size of 500 nm after stagger spinning. • Obtaining the equiaxial ferritic grains with an size of 600 nm after annealing. - Abstract: A new method of manufacturing tubes with nano/ultrafine grain structure by stagger spinning and recrystallization annealing is proposed in this study. Two methods of the stagger spinning process are developed, the corresponding macroforming quality, microstructural evolution and mechanical properties of the spun tubes made of ASTM 1020 steel are analysed. The results reveal that a good surface smoothness and an improved spin-formability of spun parts can be obtained by the process combining of 3-pass spinning followed by a 580 °C × 0.5 h static recrystallization and 2-pass spinning with a 580 °C × 1 h static recrystallization annealing under the severe thinning ratio of wall thickness reduction. The ferritic grains with an average initial size of 50 μm are refined to 500 nm after stagger spinning under the 87% thinning ratio of wall thickness reduction. The equiaxial ferritic grains with an average size of 600 nm are generated through re-nucleation and grain growth by subsequent recrystallization annealing at 580 °C for 1 h heat preservation. The tensile strength of spun tubes has been founded to be proportional to the reciprocal of layer spacing of pearlite (LSP), and the elongation is inversely proportional to the reciprocal of LSP. This study shows that the developed method of stagger power spinning has the potential to be used to manufacture bulk metal components with nano/ultrafine grain structure

  6. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    Energy Technology Data Exchange (ETDEWEB)

    James K. Neathery; Gary Jacobs; Amitava Sarkar; Burtron H. Davis

    2005-09-30

    In this reporting period, a study of ultra-fine iron catalyst filtration was initiated to study the behavior of ultra-fine particles during the separation of Fischer-Tropsch Synthesis (FTS) liquids filtration. The overall focus of the program is with slurry-phase FTS in slurry bubble column reactor systems. Hydrocarbon products must be separated from catalyst particles before being removed from the reactor system. An efficient wax product/catalyst separation system is a key factor for optimizing operating costs for iron-based slurry-phase FTS. Previous work has focused on catalyst particle attrition and the formation of ultra-fine iron carbide and/or carbon particles. With the current study, we are investigating how the filtration properties are affected by these chemical and physical changes of the catalyst slurry during activation/synthesis. The change of particle size during the slurry-phase FTS has monitored by withdrawing catalyst sample at different TOS. The measurement of dimension of the HRTEM images of samples showed a tremendous growth of the particles. Carbon rims of thickness 3-6 nm around the particles were observed. This growth in particle size was not due to carbon deposition on the catalyst. A conceptual design and operating philosophy was developed for an integrated wax filtration system for a 4 liter slurry bubble column reactor to be used in Phase II of this research program. The system will utilize a primary inertial hydroclone followed by a Pall Accusep cross-flow membrane. Provisions for cleaned permeate back-pulsing will be included to as a flux maintenance measure.

  7. Children exposure to indoor ultrafine particles in urban and rural school environments.

    Science.gov (United States)

    Cavaleiro Rufo, João; Madureira, Joana; Paciência, Inês; Slezakova, Klara; Pereira, Maria do Carmo; Aguiar, Lívia; Teixeira, João Paulo; Moreira, André; Oliveira Fernandes, Eduardo

    2016-07-01

    Extended exposure to ultrafine particles (UFPs) may lead to consequences in children due to their increased susceptibility when compared to older individuals. Since children spend in average 8 h/day in primary schools, assessing the number concentrations of UFPs in these institutions is important in order to evaluate the health risk for children in primary schools caused by indoor air pollution. Thus, the purpose of this study was to assess and determine the sources of indoor UFP number concentrations in urban and rural Portuguese primary schools. Indoor and outdoor ultrafine particle (UFP) number concentrations were measured in six urban schools (US) and two rural schools (RS) located in the north of Portugal, during the heating season. The mean number concentrations of indoor UFPs were significantly higher in urban schools than in rural ones (10.4 × 10(3) and 5.7 × 10(3) pt/cm(3), respectively). Higher UFP levels were associated with higher squared meters per student, floor levels closer to the ground, chalk boards, furniture or floor covering materials made of wood and windows with double-glazing. Indoor number concentrations of ultrafine-particles were inversely correlated with indoor CO2 levels. In the present work, indoor and outdoor concentrations of UFPs in public primary schools located in urban and rural areas were assessed, and the main sources were identified for each environment. The results not only showed that UFP pollution is present in augmented concentrations in US when compared to RS but also revealed some classroom/school characteristics that influence the concentrations of UFPs in primary schools.

  8. Deposition of ultrafine aerosols in F344/N rat nasal casts

    International Nuclear Information System (INIS)

    Cheng, Y.S.; Hansen, G.K.; Su, Y.F.; Yeh, H.C.; Morgan, K.T.

    1988-01-01

    Determination of regional respiratory deposition of inhaled aerosols is critical for evaluation of the health effects of air pollutants. Information on deposition of larger particles (> 0.02 μm) in the nasal passages of laboratory animals is available; the deposition fraction increases with increasing particle size. Little information on ultrafine particles less than 0.2 μm is available. Molds (models) were prepared from replica casts of the nasal passages of F344/N rats, using clear casting plastic. Total deposition of ultrafine aerosols in these casts was then determined using a unidirectional flow system. Measured pressure drops in the casts were a function of flow rate to the power of 1.4-1.6, indicating that the flow through the nasal passage was not laminar. Deposition data were obtained from these casts, using monodisperse sodium chloride aerosols with particle size ranging from 0.2 to 0.005 μm, at inspiratory and expiratory flow rates of 200 to 600 cc/min. Similar deposition data were obtained for the three casts studied. The deposition efficiency was greatest for the smallest particles, and decreased with increasing particle size and flow rate, indicating that diffusion was the dominant mechanism for deposition. At an inspiratory flow rate of 400 cc/min, which is comparable to a respiratory minute volume of 200 cc/min for mature male F344/N rats, deposition efficiencies reached 40 and 70% for 0.01 and 0.005 μm particles, respectively. Turbulent diffusion was considered to be the dominant mechanism for deposition of ultrafine particles in the nasal passage. This information is important for understanding the toxicity and carcinogenicity of submicrometer particles, including diesel soot, radon progeny and vapors. (author)

  9. Ultrafine particle emission from incinerators: the role of the fabric filter.

    Science.gov (United States)

    Buonanno, G; Scungio, M; Stabile, L; Tirler, W

    2012-01-01

    Incinerators are claimed to be responsible of particle and gaseous emissions: to this purpose Best Available Techniques (BAT) are used in the flue-gas treatment sections leading to pollutant emission lower than established threshold limit values. As regard particle emission, only a mass-based threshold limit is required by the regulatory authorities. However; in the last years the attention of medical experts moved from coarse and fine particles towards ultrafine particles (UFPs; diameter less than 0.1 microm), mainly emitted by combustion processes. According to toxicological and epidemiological studies, ultrafine particles could represent a risk for health and environment. Therefore, it is necessary to quantify particle emissions from incinerators also to perform an exposure assessment for the human populations living in their surrounding areas. A further topic to be stressed in the UFP emission from incinerators is the particle filtration efficiency as function of different flue-gas treatment sections. In fact, it could be somehow important to know which particle filtration method is able to assure high abatement efficiency also in terms of UFPs. To this purpose, in the present work experimental results in terms of ultrafine particle emissions from several incineration plants are reported. Experimental campaigns were carried out in the period 2007-2010 by measuring UFP number distributions and total concentrations at the stack of five plants through condensation particle counters and mobility particle sizer spectrometers. Average total particle number concentrations ranging from 0.4 x 10(3) to 6.0 x 10(3) particles cm(-3) were measured at the stack of the analyzed plants. Further experimental campaigns were performed to characterize particle levels before the fabric filters in two of the analyzed plants in order to deepen their particle reduction effect; particle concentrations higher than 1 x 10(7) particles cm(-3) were measured, leading to filtration

  10. Ultrafine particles cause cytoskeletal dysfunctions in macrophages: role of intracellular calcium

    Directory of Open Access Journals (Sweden)

    Brown David M

    2005-10-01

    Full Text Available Abstract Background Particulate air pollution is reported to cause adverse health effects in susceptible individuals. Since most of these particles are derived form combustion processes, the primary composition product is carbon with a very small diameter (ultrafine, less than 100 nm in diameter. Besides the induction of reactive oxygen species and inflammation, ultrafine particles (UFP can cause intracellular calcium transients and suppression of defense mechanisms of alveolar macrophages, such as impaired migration or phagocytosis. Methods In this study the role of intracellular calcium transients caused by UFP was studied on cytoskeleton related functions in J774A.1 macrophages. Different types of fine and ultrafine carbon black particles (CB and ufCB, respectively, such as elemental carbon (EC90, commercial carbon (Printex 90, diesel particulate matter (DEP and urban dust (UD, were investigated. Phagosome transport mechanisms and mechanical cytoskeletal integrity were studied by cytomagnetometry and cell viability was studied by fluorescence microscopy. Macrophages were exposed in vitro with 100 and 320 μg UFP/ml/million cells for 4 hours in serum free medium. Calcium antagonists Verapamil, BAPTA-AM and W-7 were used to block calcium channels in the membrane, to chelate intracellular calcium or to inhibit the calmodulin signaling pathways, respectively. Results Impaired phagosome transport and increased cytoskeletal stiffness occurred at EC90 and P90 concentrations of 100 μg/ml/million cells and above, but not with DEP or UD. Verapamil and W-7, but not BAPTA-AM inhibited the cytoskeletal dysfunctions caused by EC90 or P90. Additionally the presence of 5% serum or 1% bovine serum albumin (BSA suppressed the cytoskeletal dysfunctions. Cell viability showed similar results, where co-culture of ufCB together with Verapamil, W-7, FCS or BSA produced less cell dead compared to the particles only.

  11. Ultrafine WC-Ni cemented carbides fabricated by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Rong Huiyong [School of Engineering and Technology, China University of Geosciences at Beijing, Beijing 100083 (China); Peng Zhijian, E-mail: pengzhijian@cugb.edu.cn [School of Engineering and Technology, China University of Geosciences at Beijing, Beijing 100083 (China); Ren Xiaoyong; Peng Ying; Wang Chengbiao; Fu Zhiqiang [School of Engineering and Technology, China University of Geosciences at Beijing, Beijing 100083 (China); Qi Longhao; Miao Hezhuo [State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Ultrafine WC-Ni cemented carbides with average WC grain size of about 330 nm prepared by combination of sparking plasma sintering and grain growth inhibitors. Black-Right-Pointing-Pointer Very short mean free path of about 22 nm for crack in metal binder of the obtained materials. Black-Right-Pointing-Pointer Higher hardness than those of WC-Co cemented carbide counterparts sintered by rapid sintering. Black-Right-Pointing-Pointer Observation of fracture along metal binder and no carbon-carbon fracture face. - Abstract: With VC and TaC as WC grain growth inhibitors, ultrafine WC-Ni cemented carbides with different fractions (6-10 wt%) of binder metal nickel were fabricated by utilizing high energy milling together with spark plasma sintering. In the obtained samples, only WC and Ni phases were detected in X-ray diffraction limit. The microstructure of the specimens was examined on fractural, polished, and polished/etched surfaces by scanning electron microscopy, and the results revealed that the average WC grain size of the WC-Ni cemented carbides was about 330 nm, and there were lots of micro-pores in the samples. The relative density of the samples was all higher than 92%. But the measurement of hardness and flexural strength indicated that the existence of micro-pores had no significant influence on the performance of the obtained materials. On the basis of observation on the micro-fracture surface of the samples, it was found that fractures occurred along the binder metal, and the obtained ultrafine WC-Ni cemented carbides showed a very short binder mean free path (about 22 nm), thus resulting in excellent performance in mechanical strength.

  12. Ultrafine and fine particle formation in a naturally ventilated office as a result of reactions between ozone and scented products

    DEFF Research Database (Denmark)

    Toftum, Jørn; Dijken, F. v.

    2003-01-01

    Ultrafine and fine particle formation as a result of chemical reactions between ozone and four different air fresheners and a typical lemon-scented domestic cleaner was studied in a fully furnished, naturally ventilated office. The study showed that under conditions representative of those...... occurring in such offices, air fresheners or scented cleaners may react with ozone to form secondary organic aerosols (SOA). The tested air fresheners were relatively small sources of SOA with detectable increases occurring only in the ultrafine particle number concentration. With the cleaner, also...

  13. Surface grain coarsening and surface softening during machining of ultra-fine grained titanium

    Directory of Open Access Journals (Sweden)

    Symonova A.A.

    2012-01-01

    Full Text Available Experiments are run to show that different machining conditions applied to ultra-fine grained pure titanium lead to different levels of grain coarsening and softening near the machined surface. Under “hard” machining conditions the upper 40 microns of the machined surface are altered with a decreased microhardness. The experimental results are reasonably reproduced by model calculations. Expanding the parameter field of the model calculations, the surface coarsening diagram and the surface softening diagram due to machining are presented, showing the region of technological parameters, under which neither grain coarsening nor softening takes place along the machined surface.

  14. Nanocapillary Atmospheric Pressure Plasma Jet: A Tool for Ultrafine Maskless Surface Modification at Atmospheric Pressure.

    Science.gov (United States)

    Motrescu, Iuliana; Nagatsu, Masaaki

    2016-05-18

    With respect to microsized surface functionalization techniques we proposed the use of a maskless, versatile, simple tool, represented by a nano- or microcapillary atmospheric pressure plasma jet for producing microsized controlled etching, chemical vapor deposition, and chemical modification patterns on polymeric surfaces. In this work we show the possibility of size-controlled surface amination, and we discuss it as a function of different processing parameters. Moreover, we prove the successful connection of labeled sugar chains on the functionalized microscale patterns, indicating the possibility to use ultrafine capillary atmospheric pressure plasma jets as versatile tools for biosensing, tissue engineering, and related biomedical applications.

  15. Association between short-term exposure to ultrafine particles and mortality in eight European urban areas

    DEFF Research Database (Denmark)

    Stafoggia, Massimo; Schneider, Alexandra; Cyrys, Josef

    2017-01-01

    urban areas of Finland, Sweden, Denmark, Germany, Italy, Spain, and Greece, between 1999 and 2013. We applied city-specific time-series Poisson regression models and pooled them with random-effects meta-analysis. RESULTS: We estimated a weak, delayed association between particle number concentration...... and particulate matter (PM) and daily mortality in eight European urban areas. METHODS: We collected daily data on non-accidental and cardio-respiratory mortality, particle number concentrations (as proxy for ultrafine particle number concentration), fine and coarse PM, gases and meteorologic parameters in eight...

  16. Direct synthesis of ultrafine tetragonal BaTiO3 nanoparticles at room temperature

    Directory of Open Access Journals (Sweden)

    Hu Yong

    2011-01-01

    Full Text Available Abstract A large quantity of ultrafine tetragonal barium titanate (BaTiO3 nanoparticles is directly synthesized at room temperature. The crystalline form and grain size are checked by both X-ray diffraction and transmission electron microscopy. The results revealed that the perovskite nanoparticles as fine as 7 nm have been synthesized. The phase transition of the as-prepared nanoparticles is investigated by the temperature-dependent Raman spectrum and shows the similar tendency to that of bulk BaTiO3 materials. It is confirmed that the nanoparticles have tetragonal phase at room temperature.

  17. Preparation of Ultrafine CVD WC Powders Deposited from WCl6 Gas Mixtures

    OpenAIRE

    Tang, Xing; Haubner, R.; Lux, B.; Kieffer, B.

    1995-01-01

    Ultrafine WC powders were produced from WCl6-C3H8-H2 gaz mixtures in a conventional tubular hot-wall downstream CVD reactor. At reaction temperatures between 1100 and 1550°C powders containing W, W2C, WC and carbon were produced. The overall chemical compositions of the tungsten compounds as well as the free carbon contents depended strongly on the reaction temperature and the ratio of the reaction gases introduced. With increased reaction temperature and exposure time the amount of tungsten ...

  18. Correlation of Air Quality Data to Ultrafine Particles (UFP Concentration and Size Distribution in Ambient Air

    Directory of Open Access Journals (Sweden)

    Werner Hofmann

    2010-07-01

    Full Text Available This study monitored ultrafine particles (UFP concurrent with environmental air quality data, investigating whether already existing instrumentation used by environmental authorities can provide reference values for estimating UFP concentrations. Of particular interest was the relation of UFP to PM10 (particulate matter and nitrogen oxides (NOx, NO2 in ambient air. Existing PM measurement methods alone did not correspond exactly enough with the actual particle number, but we observed a link between NOx and NO2 to UFP concentration. The combined data could act as proxy-indicator for authorities in estimating particle number concentrations, but cannot replace UFP monitoring.

  19. Gradient ultrafine-grained titanium: Computational study of mechanical and damage behavior

    DEFF Research Database (Denmark)

    Liu, Hongsheng; Mishnaevsky, Leon

    2014-01-01

    A computational model of ultrafine-grained (UFG) titanium with random and gradient distribution based on Voronoi tessellation and the composite model of nanomaterials is developed. The effect of grain size, non-equilibrium state of the grain boundary phase (characterized by the initial dislocation...... density and diffusion coefficient) and gradient of grain sizes on the mechanical behavior and damage initiation of the UFG titanium are studied in numerical experiments. Using computational experiments, the authors determined the likely damage criterion (dislocation-based model) and found several effects...

  20. Characterizing the spatial distribution of ambient ultrafine particles in Toronto, Canada: A land use regression model.

    Science.gov (United States)

    Weichenthal, Scott; Van Ryswyk, Keith; Goldstein, Alon; Shekarrizfard, Maryam; Hatzopoulou, Marianne

    2016-01-01

    Exposure models are needed to evaluate the chronic health effects of ambient ultrafine particles (bus routes as well as variables for the number of on-street trees, parks, open space, and the length of bus routes within a 100 m buffer. There was no systematic difference between measured and predicted values when the model was evaluated in an external dataset, although the R(2) value decreased (R(2) = 50%). This model will be used to evaluate the chronic health effects of UFPs using population-based cohorts in the Toronto area. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  1. Scratch-induced deformation in fine- and ultrafine-grained bulk alumina

    International Nuclear Information System (INIS)

    Huang, Lin; Zhang, Zhihui; Zhao, Yonghao; Yao, Wenlong; Mukherjee, Amiya K.; Schoenung, Julie M.

    2010-01-01

    The nanoscratch behavior of two bulk α-alumina samples with 1.3 μm and 290 nm average grain sizes, respectively, was investigated using a nanoindenter in scratch mode, in combination with atomic force and scanning electron microscopy. A ductile to brittle transition was observed in the fine-grained sample, while the ultrafine-grained sample exhibited predominantly ductile deformation with a fish-bone feature indicative of a stick-slip mechanism. These findings suggest that grain refinement can increase the potential for plastic deformation in ceramics.

  2. Development and manufacture of ultra-fine NbTi filament wires at ALSTHOM

    International Nuclear Information System (INIS)

    Hoang, G.K.; Laumond, Y.; Sabrie, J.L.; Dubots, P.

    1986-01-01

    Ultra-fine NbTi filament wires have been developed and manufactured by ALSTHOM. It is now possible to produce industrial copper -copper-nickel matrix wires with 0.6 mu m NbTi filaments for use in 50 / 60 Hz machines. Smaller filaments with diameters down to 0.08 mu m have been obtained with 254 100 filament wire samples. Studies are now being carried out on copper matrix conductors to reduce the filament diameter. The first results show that it is possible to obtain submicron filaments even in copper matrix wires

  3. Initial study of dry ultrafine coal beneficiation utilizing triboelectric charging with subsequent electrostatic separation

    Energy Technology Data Exchange (ETDEWEB)

    Link, T.A.; Killmeyer, R.P.; Elstrodt, R.H.; Haden, N.H.

    1990-10-01

    A novel, dry process using electrostatics to beneficiate ultrafine coal is being developed by the Coal Preparation Division at the Pittsburgh Energy Technology Center. The historical concept of triboelectricity and its eventual use as a means of charging coal for electrostatic separation will be discussed. Test data from a first-generation and a second-generation Tribo-Electrostatic separator are presented showing the effects of feed particle size, separator voltage, solids concentration in air, and particle velocity on separation performance. 10 refs., 10 figs., 9 tabs.

  4. High strength and utilizable ductility of bulk ultrafine-grained Cu-Al alloys

    Science.gov (United States)

    An, X. H.; Han, W. Z.; Huang, C. X.; Zhang, P.; Yang, G.; Wu, S. D.; Zhang, Z. F.

    2008-05-01

    Lack of plasticity is the main drawback for nearly all ultrafine-grained (UFG) materials, which restricts their practical applications. Bulk UFG Cu-Al alloys have been fabricated by using equal channel angular pressing technique. Its ductility was improved to exceed the criteria for structural utility while maintaining a high strength by designing the microstructure via alloying. Factors resulting in the simultaneously enhanced strength and ductility of UFG Cu-Al alloys are the formation of deformation twins and their extensive intersections facilitating accumulation of dislocations.

  5. Ellipsometric Characterization of Thin Films from Multicomponent Chalcogenide Glasses for Application in Modern Optical Devices

    Directory of Open Access Journals (Sweden)

    R. Todorov

    2013-01-01

    Full Text Available A review is given on the application of the reflectance ellipsometry for optical characterization of bulk materials and thin films with thickness between λ/20 and 2λ (at λ=632.8 nm. The knowledge of the optical constants (refractive index, n, and extinction coefficient, k of thin films is of a great importance from the point of view of modelling and controlling the manufacture of various optical elements, such as waveguides, diffraction gratings, and microlenses. The presented results concern the optical properties of thin films from multicomponent chalcogenide glasses on the base of As2S3 and GeS2 determined by multiple-angle-of-incidence ellipsometry and regarded as a function of the composition and thickness. The homogeneity of the films is verified by applying single-angle calculations at different angles. Due to decomposition of the bulk glass during thermal evaporation, an optical inhomogeneity of the thin As (Ge-S-Bi(Tl films is observed. The profile of n in depth of thin As-S-Tl (Bi films was investigated by evaporation of discrete layers. It is demonstrated that homogenous layers from the previous compounds with controlled composition can be deposited by coevaporation of As2S3 and metals or their compounds (Bi, Tl, In2S3.

  6. Computational Design of Multi-component Bio-Inspired Bilayer Membranes

    Directory of Open Access Journals (Sweden)

    Evan Koufos

    2014-04-01

    Full Text Available Our investigation is motivated by the need to design bilayer membranes with tunable interfacial and mechanical properties for use in a range of applications, such as targeted drug delivery, sensing and imaging. We draw inspiration from biological cell membranes and focus on their principal constituents. In this paper, we present our results on the role of molecular architecture on the interfacial, structural and dynamical properties of bio-inspired membranes. We focus on four lipid architectures with variations in the head group shape and the hydrocarbon tail length. Each lipid species is composed of a hydrophilic head group and two hydrophobic tails. In addition, we study a model of the Cholesterol molecule to understand the interfacial properties of a bilayer membrane composed of rigid, single-tail molecular species. We demonstrate the properties of the bilayer membranes to be determined by the molecular architecture and rigidity of the constituent species. Finally, we demonstrate the formation of a stable mixed bilayer membrane composed of Cholesterol and one of the phospholipid species. Our approach can be adopted to design multi-component bilayer membranes with tunable interfacial and mechanical properties. We use a Molecular Dynamics-based mesoscopic simulation technique called Dissipative Particle Dynamics that resolves the molecular details of the components through soft-sphere coarse-grained models and reproduces the hydrodynamic behavior of the system over extended time scales.

  7. Observation of the Dissolution from Residual Phase Multicomponent Nonaqueous Phase Liquids

    Science.gov (United States)

    Brahma, P. P.; Harmon, T. C.

    2001-05-01

    Nonaqueous phase liquid (NAPL) subsurface contaminants (e.g., fuels, solvents) are typically complex mixtures. This work examines the impact of intra-NAPL diffusion and mixture nonideality on dissolution from multicomponent NAPL mixtures through a computational and experimental approach. Downstream concentrations are observed during the controlled dissolution of three-component residual NAPL in a three-dimensional model aquifer. These results, when compared to single-component residual NAPL results, are used to identify (1) if and when intra-NAPL interactions contribute significantly to the overall dissolution process, and (2) the role that factors, such as length scale, hydrodynamic conditions, and/or mixture ideality, play in determining (1). Model ternary mixtures were chosen to represent a range of ideality based on UNIFAC-estimated activity coefficients. In this case, tetrachloroethene (PCE), trichloroethene (TCE), and 1,1,1-trichloroethane (TCA) were selected as the ideal mixture. The mixture of PCE, TCE, and octanol was shown to exhibit significant deviations from ideality and selected to represent a nonideal mixture. Experimental results for the two mixtures are compared to each other and to analogous results from pure PCE dissolution experiments. The experimental results are further interpreted using a three-dimensional transport model subject to a boundary concentration history calculated using a ternary intra-NAPL diffusion/dissolution submodel. The combined experimental and computational findings are used to delineate conditions for which a detailed physical-chemical description of NAPL dissolution is warranted and those for which a simplified description will suffice.

  8. On the direct detection of multi-component dark matter: sensitivity studies and parameter estimation

    Science.gov (United States)

    Herrero-Garcia, Juan; Scaffidi, Andre; White, Martin; Williams, Anthony G.

    2017-11-01

    We study the case of multi-component dark matter, in particular how direct detection signals are modified in the presence of several stable weakly-interacting-massive particles. Assuming a positive signal in a future direct detection experiment, stemming from two dark matter components, we study the region in parameter space where it is possible to distinguish a one from a two-component dark matter spectrum. First, we leave as free parameters the two dark matter masses and show that the two hypotheses can be significantly discriminated for a range of dark matter masses with their splitting being the critical factor. We then investigate how including the effects of different interaction strengths, local densities or velocity dispersions for the two components modifies these conclusions. We also consider the case of isospin-violating couplings. In all scenarios, we show results for various types of nuclei both for elastic spin-independent and spin-dependent interactions. Finally, assuming that the two-component hypothesis is confirmed, we quantify the accuracy with which the parameters can be extracted and discuss the different degeneracies that occur. This includes studying the case in which only a single experiment observes a signal, and also the scenario of having two signals from two different experiments, in which case the ratios of the couplings to neutrons and protons may also be extracted.

  9. Monte Carlo simulations of electrical percolation in multicomponent thin films with nanofillers

    Science.gov (United States)

    Ni, Xiaojuan; Hui, Chao; Su, Ninghai; Jiang, Wei; Liu, Feng

    2018-02-01

    We developed a 2D disk-stick percolation model to investigate the electrical percolation behavior of an insulating thin film reinforced with 1D and 2D conductive nanofillers via Monte Carlo simulation. Numerical predictions of the percolation threshold in single component thin films showed good agreement with the previous published work, validating our model for investigating the characteristics of the percolation phenomena. Parametric studies of size effect, i.e., length of 1D nanofiller and diameter of 2D nanofiller, were carried out to predict the electrical percolation threshold for hybrid systems. The relationships between the nanofillers in two hybrid systems was established, which showed differences from previous linear assumption. The effective electrical conductance was evaluated through Kirchhoff’s current law by transforming it into a resistor network. The equivalent resistance was obtained from the distribution of nodal voltages by solving a system of linear equations with a Gaussian elimination method. We examined the effects of stick length, relative concentration, and contact patterns of 1D/2D inclusions on electrical performance. One novel aspect of our study is its ability to investigate the effective conductance of nanocomposites as a function of relative concentrations, which shows there is a synergistic effect when nanofillers with different dimensionalities combine properly. Our work provides an important theoretical basis for designing the conductive networks and predicting the percolation properties of multicomponent nanocomposites.

  10. Nonequilibrium Contribution to the Rate of Reaction. III. Isothermal Multicomponent Systems

    Science.gov (United States)

    Shizgal, B.; Karplus, M.

    1970-10-01

    The nonequilibrium contribution to the reaction rate of an isothermal multicomponent system is obtained by solution of the appropriate Chapman-Enskog equation; the system is composed of reactive species in contact with a heat bath of inert atoms M.

  11. Time-dependent density functional theory for multi-component systems

    International Nuclear Information System (INIS)

    Tiecheng Li; Peiqing Tong

    1985-10-01

    The Runge-Gross version of Hohenberg-Kohn-Sham's density functional theory is generalized to multi-component systems, both for arbitrary time-dependent pure states and for arbitrary time-dependent ensembles. (author)

  12. Transition-Metal-Free Multicomponent Benzannulation Reactions for the Construction of Polysubstituted Benzene Derivatives.

    Science.gov (United States)

    Shu, Wen-Ming; Zheng, Kai-Lu; Ma, Jun-Rui; Wu, An-Xin

    2015-11-06

    A transition-metal-free multicomponent benzannulation reaction was developed from readily available ketones, nitro-olefins, and diester acetylenedicarboxylate. This approach provides a straightforward and efficient way to construct polysubstituted benzene derivatives under mild conditions in high yields.

  13. Mixed-mode chromatography with zwitterionic phosphopeptidomimetic selectors from Ugi multicomponent reaction

    NARCIS (Netherlands)

    Gargano, Andrea F G; Leek, Tomas; Lindner, Wolfgang; Lämmerhofer, Michael

    2013-01-01

    In the present contribution a novel Ugi multicomponent reaction (MCR) was used to generate zwitterionic chromatographic selectors with capability for application in mixed-mode chromatography featuring complementary selectivities in reversed-phase (RP) and hydrophilic interaction liquid

  14. Utilization of fly ash and ultrafine GGBS for higher strength foam concrete

    Science.gov (United States)

    Gowri, R.; Anand, K. B.

    2018-02-01

    Foam concrete is a widely accepted construction material, which is popular for diverse construction applications such as, thermal insulation in buildings, lightweight concrete blocks, ground stabilization, void filling etc. Currently, foam concrete is being used for structural applications with a density above 1800kg/m3. This study focuses on evolving mix proportions for foam concrete with a material density in the range of 1200 kg/m3 to 1600 kg/m3, so as to obtain strength ranges that will be sufficient to adopt it as a structural material. Foam concrete is made lighter by adding pre-formed foam of a particular density to the mortar mix. The foaming agent used in this study is Sodium Lauryl Sulphate and in order to densify the foam generated, Sodium hydroxide solution at a normality of one is also added. In this study efforts are made to make it a sustainable construction material by incorporating industrial waste products such as ultrafine GGBS as partial replacement of cement and fly ash for replacement of fine aggregate. The fresh state and hardened state properties of foam concrete at varying proportions of cement, sand, water and additives are evaluated. The proportion of ultrafine GGBS and fly ash in the foam concrete mix are varied aiming at higher compressive strength. Studies on air void-strength relationship of foam concrete are also included in this paper.

  15. Number size distribution of fine and ultrafine fume particles from various welding processes.

    Science.gov (United States)

    Brand, Peter; Lenz, Klaus; Reisgen, Uwe; Kraus, Thomas

    2013-04-01

    Studies in the field of environmental epidemiology indicate that for the adverse effect of inhaled particles not only particle mass is crucial but also particle size is. Ultrafine particles with diameters below 100 nm are of special interest since these particles have high surface area to mass ratio and have properties which differ from those of larger particles. In this paper, particle size distributions of various welding and joining techniques were measured close to the welding process using a fast mobility particle sizer (FMPS). It turned out that welding processes with high mass emission rates (manual metal arc welding, metal active gas welding, metal inert gas welding, metal inert gas soldering, and laser welding) show mainly agglomerated particles with diameters above 100 nm and only few particles in the size range below 50 nm (10 to 15%). Welding processes with low mass emission rates (tungsten inert gas welding and resistance spot welding) emit predominantly ultrafine particles with diameters well below 100 nm. This finding can be explained by considerably faster agglomeration processes in welding processes with high mass emission rates. Although mass emission is low for tungsten inert gas welding and resistance spot welding, due to the low particle size of the fume, these processes cannot be labeled as toxicologically irrelevant and should be further investigated.

  16. Ultrafine particles from power plants: Evaluation of WRF-Chem simulations with airborne measurements

    Science.gov (United States)

    Forkel, Renate; Junkermann, Wolfgang

    2017-04-01

    Ultrafine particles (UFP, particles with a diameter health and have a potential effect on climate as their presence affects the number concentration of cloud condensation nuclei. Despite of the possibly hazardous effects no regulations exist for this size class of ambient air pollution particles. While ground based continuous measurements of UFP are performed in Germany at several sites (e.g. the German Ultrafine Aerosol Network GUAN, Birmili et al. 2016, doi:10.5194/essd-8-355-2016) information about the vertical distribution of UFP within the atmospheric boundary layer is only scarce. This gap has been closed during the last years by regional-scale airborne surveys for UFP concentrations and size distributions over Germany (Junkermann et al., 2016, doi: 10.3402/tellusb.v68.29250) and Australia (Junkermann and Hacker, 2015, doi: 10.3402/tellusb.v67.25308). Power stations and refineries have been identified as a major source of UFP in Germany with observed particle concentrations > 50000 particles cm-3 downwind of these elevated point sources. Nested WRF-Chem simulations with 2 km grid width for the innermost domain are performed with UFP emission source strengths derived from the measurements in order to study the advection and vertical exchange of UFP from power plants near the Czech and Polish border and their impact on planetary boundary layer particle patterns. The simulations are evaluated against the airborne observations and the downward mixing of the UFP from the elevated sources is studied.

  17. [Experimental study on the size spectra and emission factor of ultrafine particle from coal combustion].

    Science.gov (United States)

    Sun, Zai; Yang, Wen-jun; Xie, Xiao-fang; Chen, Qiu-fang; Cai, Zhi-liang

    2014-12-01

    The emission characteristics of ultrafine particles released from pulverized coal combustion were studied, the size spectra of ultrafine particles (5.6-560 nm) were measured with FMPS (fast mobility particle sizer) on a self-built aerosol experiment platform. Meanwhile, a particle dynamic evolution model was established to obtain the particle deposition rate and the emission rate through the optimized algorithm. Finally, the emission factor was calculated. The results showed that at the beginning of particle generation, the size spectra were polydisperse and complex, the initial size spectra was mainly composed of three modes including 10 nm, 30-40 nm and 100-200 nm. Among them, the number concentration of mode around 10 nm was higher than those of other modes, the size spectrum of around 100-200 nm was lognormal distributed, with a CMD (count median diameter) of around 16 nm. Then, as time went on, the total number concentration was decayed by exponential law, the CMD first increased and then tended to be stable gradually. The calculation results showed that the emission factor of particles from coal combustion under laboratory condition was (5.54 x 10(12) ± 2.18 x 10(12)) unit x g(-1).

  18. On the time-averaging of ultrafine particle number size spectra in vehicular plumes

    Directory of Open Access Journals (Sweden)

    X. H. Yao

    2006-01-01

    Full Text Available Ultrafine vehicular particle (<100 nm number size distributions presented in the literature are mostly averages of long scan-time (~30 s or more spectra mainly due to the non-availability of commercial instruments that can measure particle distributions in the <10 nm to 100 nm range faster than 30 s even though individual researchers have built faster (1–2.5 s scanning instruments. With the introduction of the Engine Exhaust Particle Sizer (EEPS in 2004, high time-resolution (1 full 32-channel spectrum per second particle size distribution data become possible and allow atmospheric researchers to study the characteristics of ultrafine vehicular particles in rapidly and perhaps randomly varying high concentration environments such as roadside, on-road and tunnel. In this study, particle size distributions in these environments were found to vary as rapidly as one second frequently. This poses the question on the generality of using averages of long scan-time spectra for dynamic and/or mechanistic studies in rapidly and perhaps randomly varying high concentration environments. One-second EEPS data taken at roadside, on roads and in tunnels by a mobile platform are time-averaged to yield 5, 10, 30 and 120 s distributions to answer this question.

  19. An enhanced-gravity method to recover ultra-fine coal from tailings: Falcon concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Filiz Oruc; Selcuk Ozgen; Eyup Sabah [Afyon Kocatepe University, Afyonkarahisar (Turkey). Department of Mining Engineering

    2010-09-15

    The Falcon concentrator is an enhanced-gravity separator used for the concentration of fine and ultra-fine minerals. This study was conducted to evaluate the effects of different process variables on the performance of the Falcon SB-40 concentrator for beneficiation of tailings to recover ultra-fine coal. Various operating and design conditions such as bowl speed (G force), water pressure, pulp solid ratio and pulp feed rate were investigated. A hydrocyclone was used for pre-enrichment with the Falcon concentrator. Operation parameters of the hydrocyclone, namely feed solids, inlet pressure, vortex finder and apex diameters were investigated. In order to produce fine coal concentrates, regression equations were derived by applying the least squares method using Minitab 15 software. Response functions were produced for the ash content and the recovery of the clean coal concentrates for the performance of the hydrocyclone and Falcon concentrator under different operating conditions. Predicted values were found with the experimental values giving R{sup 2} values of between 0.73 and 0.58 for ash content and between 0.65 and 0.39 for recovery of the clean coal. It was shown that under optimized conditions the Falcon concentrator can produce a clean coal with an ash value of 36% from a feed coal of about 66% ash. 19 refs., 7 figs., 5 tabs.

  20. Ultrafine particles in inhabited areas in the Arctic - From very low to high concentrations

    DEFF Research Database (Denmark)

    Pétursdóttir, Una; Kirkelund, Gunvor Marie; Press-Kristensen, Kåre

    2017-01-01

    The Arctic is considered a pristine environment, where pollution mainly originates from global sources. The present study examines particle number concentrations (PNCs) and the main sources of airborne ultrafine particles (UFPs, d < 100 nm) in the town Sisimiut and two nearby settlements, Sarfann......The Arctic is considered a pristine environment, where pollution mainly originates from global sources. The present study examines particle number concentrations (PNCs) and the main sources of airborne ultrafine particles (UFPs, d ..., Sarfannguit and Itilleq, in West Greenland. Measurements were carried out during three weeks in April and May 2016. Air temperatures during the measurements ranged from −4.4 to +8.7 °C. A portable condensation particle counter (P-Trak) was used for the measurements. Results showed that the lowest...... in Sisimiut, while subsequent measurements at the same location showed much lower PNCs. The presence of heavy machinery elevated PNCs highly during two measurement events, giving PNCs up to 270,993 cm−3 but dropping to 1180 cm−3 10 min later, after the vehicle had passed by. A measurement event in Sisimiut...

  1. Shape effect of ultrafine-grained structure on static fracture toughness in low-alloy steel

    Science.gov (United States)

    Inoue, Tadanobu; Kimura, Yuuji; Ochiai, Shojiro

    2012-01-01

    A 0.4C-2Si-1Cr-1Mo steel with an ultrafine elongated grain (UFEG) structure and an ultrafine equiaxed grain (UFG) structure was fabricated by multipass caliber rolling at 773 K and subsequent annealing at 973 K. A static three-point bending test was conducted at ambient temperature and at 77 K. The strength–toughness balance of the developed steels was markedly better than that of conventionally quenched and tempered steel with a martensitic structure. In particular, the static fracture toughness of the UFEG steel, having a yield strength of 1.86 GPa at ambient temperature, was improved by more than 40 times compared with conventional steel having a yield strength of 1.51 GPa. Furthermore, even at 77 K, the fracture toughness of the UFEG steel was about eight times higher than that of the conventional and UFG steels, despite the high strength of the UFEG steel (2.26 GPa). The UFG steel exhibited brittle fracture behavior at 77 K, as did the conventional steel, and no dimple structure was observed on the fracture surface. Therefore, it is difficult to improve the low-temperature toughness of the UFG steel by grain refinement only. The shape of crystal grains plays an important role in delamination toughening, as do their refinement and orientation. PMID:27877493

  2. Review on ultrafined/nanostructured magnesium alloys produced through severe plastic deformation: microstructures

    Directory of Open Access Journals (Sweden)

    Mahmood Fatemi

    2015-12-01

    Full Text Available A review on the microstructural evolution in magnesium alloys during severe plastic deformation waspresented. The challenges deserved to achieve ultrafine/ nanostructured magnesium were discussed.The characteristics of the processed materials are influenced by three main factors, including idifficult processing at low temperatures, ii high temperature processing and the occurrence ofdynamic recrystallization and grain growth processes, and iii a combined effect of grain refinementand crystallographic texture changes. Reviewing the published results indicate that there are twopotential difficulties with severe deformation of magnesium alloys. First, it is very hard to achievehomogeneous ultrafined microstructure with initial coarse grains. The second is the dependency ofmicrostructure development on the initial grain size and on the imposed strain level. It was clarifiedthat different grain refining mechanisms may be contributed along the course of multi-pass severedeformation. It was clarified that discontinuous recrystallization takes places during the first stages ofdeformation, whereas continuous refinement of the recrystallized grain may be realized at consecutivepasses. Shear band formation as well as twinning were demonstrated to play a significant role in grainrefinement of magnesium alloy. Also, the higher the processing temperature employed the morehomogeneous microstructure may be achieved with higher share of low angle grain boundaries.

  3. Investigation of ultrafine grained AA1050 fabricated by accumulative roll bonding

    International Nuclear Information System (INIS)

    Su, Lihong; Lu, Cheng; Li, Huijun; Deng, Guanyu; Tieu, Kiet

    2014-01-01

    Accumulative roll bonding (ARB) is an effective method to produce ultrafine-grained (UFG) sheet materials with high strength. In this work, fully annealed AA1050 sheet with an initial thickness of 1.5 mm was processed by ARB up to five cycles. The microstructure was examined by optical microscopy (OM) and transmission electron microscopy (TEM). The results revealed that ARB is a promising process for fabricating ultrafine grained structures in aluminium sheets and the average grain size after 5-cycle ARB reached approximately 300 nm. Meanwhile, a remarkable enhancement in the strength was achieved and the value was about three times the strength of starting material. The microstructure at the bond interface introduced during ARB was investigated and its influence was discussed in detail. In addition, the microstructure and mechanical properties after ARB were compared with that after deformation by equal channel angular pressing (ECAP) up to the same strain. It has been found that ARB is more efficient in grain refinement and strengthening, which can be attributed to the different deformation modes of the two techniques

  4. Ultrafine-Grained Precipitation Hardened Copper Alloys by Swaging or Accumulative Roll Bonding

    Directory of Open Access Journals (Sweden)

    Igor Altenberger

    2015-05-01

    Full Text Available There is an increasing demand in the industry for conductive high strength copper alloys. Traditionally, alloy systems capable of precipitation hardening have been the first choice for electromechanical connector materials. Recently, ultrafine-grained materials have gained enormous attention in the materials science community as well as in first industrial applications (see, for instance, proceedings of NANO SPD conferences. In this study the potential of precipitation hardened ultra-fine grained copper alloys is outlined and discussed. For this purpose, swaging or accumulative roll-bonding is applied to typical precipitation hardened high-strength copper alloys such as Corson alloys. A detailed description of the microstructure is given by means of EBSD, Electron Channeling Imaging (ECCI methods and consequences for mechanical properties (tensile strength as well as fatigue and electrical conductivity are discussed. Finally the role of precipitates for thermal stability is investigated and promising concepts (e.g. tailoring of stacking fault energy for grain size reduction and alloy systems for the future are proposed and discussed. The relation between electrical conductivity and strength is reported.

  5. Oral fast-dissolving drug delivery membranes prepared from electrospun polyvinylpyrrolidone ultrafine fibers

    International Nuclear Information System (INIS)

    Yu Dengguang; Shen Xiaxia; Zhu Limin; Branford-White, Chris; White, Kenneth; Annie Bligh, S W

    2009-01-01

    Oral fast-dissolving drug delivery membranes (FDMs) for poorly water-soluble drugs were prepared via electrospinning technology with ibuprofen as the model drug and polyvinylpyrrolidone (PVP) K30 as the filament-forming polymer and drug carrier. Results from differential scanning calorimetry, x-ray diffraction, and morphological observations demonstrated that ibuprofen was distributed in the ultrafine fibers in the form of nanosolid dispersions and the physical status of drug was an amorphous or molecular form, different from that of the pure drug and a physical mixture of PVP and ibuprofen. Fourier-transform infrared spectroscopy results illustrated that the main interactions between PVP and ibuprofen were mediated through hydrogen bonding. Pharmacotechnical tests showed that FDMs with different drug contents had almost the same wetting and disintegrating times, about 15 and 8 s, respectively, but significantly different drug dissolution rates due to the different physical status of the drug and the different drug-release-controlled mechanisms. 84.9% and 58.7% of ibuprofen was released in the first 20 s for FDMs with a drug-to-PVP ratio of 1:4 and 1:2, respectively. Electrospun ultrafine fibers have the potential to be used as solid dispersions to improve the dissolution profiles of poorly water-soluble drugs or as oral fast disintegrating drug delivery systems.

  6. Effects of temperature and inorganic salts on the adsorption of phenol from multicomponent systems onto a decolorizing carbon

    Energy Technology Data Exchange (ETDEWEB)

    Halhouli, K.A.; Darwish, N.A.; Al-Jahmany, Y.Y. [Jordan Univ. of Science and Technology, Irbid (Jordan)

    1997-12-01

    Experimental investigation of the effect of temperature and two inorganic salts (KCl and NaCl) on the adsorption of phenol from dilute (10-200 mg/dm{sup 3}) multi-component systems onto activated carbon was studied. Focusing on the adsorption of phenol, all combinations of phenol with two other aromatic organic components, (1,4-dihydroxybenzene and 4-amino,1-naphthalene sulfonic acid-sodium salt) in aqueous solutions were considered. Equilibrium isotherms at three different temperatures (30, 40, and 55{degrees}C) were generated. The adsorption of phenol from binary and ternary as well as from single aqueous systems increases with decreasing temperature, as expected of physical adsorption. Effects of KCl and NaCl salts as a concentration of 0.05 M at 30{degrees}C were also investigated. The adsorption of phenol from bisolute and trisolute systems slightly decreases by adding either of the salts.

  7. Ultrafine Particles from Traffic Emissions and Children’s Health (UPTECH in Brisbane, Queensland (Australia: Study Design and Implementation

    Directory of Open Access Journals (Sweden)

    Wafaa Nabil Ezz

    2015-02-01

    Full Text Available Ultrafine particles are particles that are less than 0.1 micrometres (µm in diameter. Due to their very small size they can penetrate deep into the lungs, and potentially cause more damage than larger particles. The Ultrafine Particles from Traffic Emissions and Children’s Health (UPTECH study is the first Australian epidemiological study to assess the health effects of ultrafine particles on children’s health in general and peripheral airways in particular. The study is being conducted in Brisbane, Australia. Continuous indoor and outdoor air pollution monitoring was conducted within each of the twenty five participating school campuses to measure particulate matter, including in the ultrafine size range, and gases. Respiratory health effects were evaluated by conducting the following tests on participating children at each school: spirometry, forced oscillation technique (FOT and multiple breath nitrogen washout test (MBNW (to assess airway function, fraction of exhaled nitric oxide (FeNO, to assess airway inflammation, blood cotinine levels (to assess exposure to second-hand tobacco smoke, and serum C-reactive protein (CRP levels (to measure systemic inflammation. A pilot study was conducted prior to commencing the main study to assess the feasibility and reliably of measurement of some of the clinical tests that have been proposed for the main study. Air pollutant exposure measurements were not included in the pilot study.

  8. Fatigue property and fatigue cracks of ultra-fine grained copper processed by equal-channel angular pressing

    Czech Academy of Sciences Publication Activity Database

    Wang, Q.; Du, Z.; Liu, X.; Kunz, Ludvík

    2011-01-01

    Roč. 2011, č. 682 (2011), s. 231-237 ISSN 1013-9826 Institutional research plan: CEZ:AV0Z20410507 Keywords : ultrafine-grained copper * equal channel angular pressing * fatigue * fatigue cracks Subject RIV: JL - Materials Fatigue, Friction Mechanics

  9. Microstructure Mechanisms Governing the Creep Life of Ultrafine-grained Cu-0.2wt.%Zr Alloy

    Czech Academy of Sciences Publication Activity Database

    Král, Petr; Svoboda, Milan; Dvořák, Jiří; Kvapilová, Marie; Sklenička, Václav

    2011-01-01

    Roč. 12, č. 12 (2011), od 72 do 72 [12th International Symposium on Physics of Materials. 04.09.2011-08.09.2011, Praha] R&D Projects: GA ČR(CZ) GAP108/11/2260 Institutional research plan: CEZ:AV0Z20410507 Keywords : ultrafine-grained materials * creep * copper alloy Subject RIV: JJ - Other Materials

  10. Plasma-assisted synthesis of monodispersed and robust Ruthenium ultrafine nanocatalysts for organosilane oxidation and oxygen evolution reactions

    NARCIS (Netherlands)

    Gnanakumar, E.S.; Ng, W.; Filiz, B.C.; Rothenberg, G.; Wang, S.; Xu, H.; Pastor-Pérez, L.; Pastor-Blas, M.M.; Sepúlveda-Escribano, A.; Yan, N.; Shiju, N.R.

    2017-01-01

    We report a facile and general approach for preparing ultrafine ruthenium nanocatalysts by using a plasma-assisted synthesis at <100 °C. The resulting Ru nanoparticles are monodispersed (typical size 2 nm) and remain that way upon loading onto carbon and TiO2 supports. This gives robust catalysts

  11. Chemical Structure and Morphology of Magnetic Ultrafine Particles Synthesized from a Ternary Gaseous Mixture Involving Cobalt Tricarbonyl Nitrosyl

    Czech Academy of Sciences Publication Activity Database

    Morita, H.; Hattori, K.; Murafa, Nataliya; Šubrt, Jan

    2015-01-01

    Roč. 28, č. 3 (2015), s. 429-434 ISSN 0914-9244 R&D Projects: GA MŠk(CZ) 7AMB14SK178 Institutional support: RVO:61388980 Keywords : gas phase photochemical reaction * magnetic ultrafine particle * cobalt tricarbonyl nitrosyl * iron pentacarbonyl Subject RIV: CA - Inorganic Chemistry Impact factor: 0.857, year: 2015

  12. Mast cells contribute to alterations in vascular reactivity and exacerbation of ischemia reperfusion injury following ultrafine PM exposure

    Science.gov (United States)

    Increased ambient fine particulate matter (FPM) concentrations are associated with increased risk for short-term and long-term adverse cardiovascular events. Ultrafine PM (UFPM) due to its size and increased surface area might be particularly toxic. Mast cells are well recognized...

  13. Inter-particle interactions and magnetocaloric effect in a sample of ultrafine Fe1-x Hgx particles in Hg

    DEFF Research Database (Denmark)

    Pedersen, Michael Stanley; Mørup, Steen; Linderoth, S.

    1997-01-01

    Ultrafine magnetic particles consisting of a metastable iron-mercury alloy in Hg have been investigated by Mossbauer spectroscopy and magnetization measurements. It was found that the magnetic particles interact strongly, and around 100 K there is a transition from a superparamagnetic state...

  14. Solvent Front Position Extraction procedure with thin-layer chromatography as a mode of multicomponent sample preparation for quantitative analysis by instrumental technique.

    Science.gov (United States)

    Klimek-Turek, A; Sikora, E; Dzido, T H

    2017-12-29

    A concept of using thin-layer chromatography to multicomponent sample preparation for quantitative determination of solutes followed by instrumental technique is presented. Thin-layer chromatography (TLC) is used to separate chosen substances and their internal standard from other components (matrix) and to form a single spot/zone containing them at the solvent front position. The location of the analytes and internal standard in the solvent front zone allows their easy extraction followed by quantitation by HPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Exposure to ultrafine particles, intracellular production of reactive oxygen species in leukocytes and altered levels of endothelial progenitor cells.

    Science.gov (United States)

    Jantzen, Kim; Møller, Peter; Karottki, Dorina Gabriela; Olsen, Yulia; Bekö, Gabriel; Clausen, Geo; Hersoug, Lars-Georg; Loft, Steffen

    2016-06-01

    Exposure to particles in the fine and ultrafine size range has been linked to induction of low-grade systemic inflammation, oxidative stress and development of cardiovascular diseases. Declining levels of endothelial progenitor cells within systemic circulation have likewise been linked to progression of cardiovascular diseases. The objective was to determine if exposure to fine and ultrafine particles from indoor and outdoor sources, assessed by personal and residential indoor monitoring, is associated with altered levels of endothelial progenitor cells, and whether such effects are related to leukocyte-mediated oxidative stress. The study utilized a cross sectional design performed in 58 study participants from a larger cohort. Levels of circulating endothelial progenitor cells, defined as either late (CD34(+)KDR(+) cells) or early (CD34(+)CD133(+)KDR(+) cells) subsets were measured using polychromatic flow cytometry. We additionally measured production of reactive oxygen species in leukocyte subsets (lymphocytes, monocytes and granulocytes) by flow cytometry using intracellular 2',7'-dichlorofluoroscein. The measurements encompassed both basal levels of reactive oxygen species production and capacity for reactive oxygen species production for each leukocyte subset. We found that the late endothelial progenitor subset was negatively associated with levels of ultrafine particles measured within the participant residences and with reactive oxygen species production capacity in lymphocytes. Additionally, the early endothelial progenitor cell levels were positively associated with a personalised measure of ultrafine particle exposure and negatively associated with both basal and capacity for reactive oxygen species production in lymphocytes and granulocytes, respectively. Our results indicate that exposure to fine and ultrafine particles derived from indoor sources may have adverse effects on human vascular health. Copyright © 2016 The Authors. Published by Elsevier

  16. The Effects on Bronchial Epithelial Mucociliary Cultures of Coarse, Fine, and Ultrafine Particulate Matter From an Underground Railway Station

    Science.gov (United States)

    Loxham, Matthew; Morgan-Walsh, Rebecca J.; Cooper, Matthew J.; Blume, Cornelia; Swindle, Emily J.; Dennison, Patrick W.; Howarth, Peter H.; Cassee, Flemming R.; Teagle, Damon A. H.; Palmer, Martin R.; Davies, Donna E.

    2015-01-01

    We have previously shown that underground railway particulate matter (PM) is rich in iron and other transition metals across coarse (PM10–2.5), fine (PM2.5), and quasi-ultrafine (PM0.18) fractions and is able to generate reactive oxygen species (ROS). However, there is little knowledge of whether the metal-rich nature of such particles exerts toxic effects in mucus-covered airway epithelial cell cultures or whether there is an increased risk posed by the ultrafine fraction. Monolayer and mucociliary air-liquid interface (ALI) cultures of primary bronchial epithelial cells (PBECs) were exposed to size-fractionated underground railway PM (1.1–11.1 µg/cm2) and release of lactate dehydrogenase and IL-8 was assayed. ROS generation was measured, and the mechanism of generation studied using desferrioxamine (DFX) and N-acetylcysteine (NAC). Expression of heme oxygenase-1 (HO-1) was determined by RT-qPCR. Particle uptake was studied by transmission electron microscopy. Underground PM increased IL-8 release from PBECs, but this was diminished in mucus-secreting ALI cultures. Fine and ultrafine PM generated a greater level of ROS than coarse PM. ROS generation by ultrafine PM was ameliorated by DFX and NAC, suggesting an iron-dependent mechanism. Despite the presence of mucus, ALI cultures displayed increased HO-1 expression. Intracellular PM was observed within vesicles, mitochondria, and free in the cytosol. The results indicate that, although the mucous layer appears to confer some protection against underground PM, ALI PBECs nonetheless detect PM and mount an antioxidant response. The combination of increased ROS-generating ability of the metal-rich ultrafine fraction and ability of PM to penetrate the mucous layer merits further research. PMID:25673499

  17. Efficient transfer of sensitivity information in multi-component models

    International Nuclear Information System (INIS)

    Abdel-Khalik, Hany S.; Rabiti, Cristian

    2011-01-01

    In support of adjoint-based sensitivity analysis, this manuscript presents a new method to efficiently transfer adjoint information between components in a multi-component model, whereas the output of one component is passed as input to the next component. Often, one is interested in evaluating the sensitivities of the responses calculated by the last component to the inputs of the first component in the overall model. The presented method has two advantages over existing methods which may be classified into two broad categories: brute force-type methods and amalgamated-type methods. First, the presented method determines the minimum number of adjoint evaluations for each component as opposed to the brute force-type methods which require full evaluation of all sensitivities for all responses calculated by each component in the overall model, which proves computationally prohibitive for realistic problems. Second, the new method treats each component as a black-box as opposed to amalgamated-type methods which requires explicit knowledge of the system of equations associated with each component in order to reach the minimum number of adjoint evaluations. (author)

  18. Multi-component solid solution alloys having high mixing entropy

    Science.gov (United States)

    Bei, Hongbin

    2015-10-06

    A multi-component high-entropy alloy includes a composition selected from the following group: VNbTaTiMoWRe, VNbTaTiMoW, VNbTaTiMoRe, VNbTaTiWRe, VNbTaMoWRe, VNbTiMoWRe, VTaTiMoWRe, NbTaTiMoWRe, VNbTaTiMo, VNbTaTiW, VNbTaMoW, VNbTiMoW, VTaTiMoW, NbTaTiMoW, VNbTaTiRe, VNbTaMoRe, VNbTiMoRe, VTaTiMoRe, NbTaTiMoRe, VNbTaWRe, VNbTiWRe, VTaTiWRe, NbTaTiWRe, VNbMoWRe, VTaMoWRe, NbTaMoWRe, VTiMoWRe, NbTiMoWRe, TaTiMoWRe, wherein relative amounts of each element vary by no more than .+-.15 atomic %.

  19. Prednisolone multicomponent nanoparticle preparation by aerosol solvent extraction system.

    Science.gov (United States)

    Moribe, Kunikazu; Fukino, Mika; Tozuka, Yuichi; Higashi, Kenjirou; Yamamoto, Keiji

    2009-10-01

    Prednisolone nanoparticles were prepared in the presence of a hydrophilic polymer and a surfactant by the aerosol solvent extraction system (ASES). A ternary mixture of prednisolone, polyethylene glycol (PEG), and sodium dodecyl sulfate (SDS) dissolved in methanol was sprayed through a nozzle into the reaction vessel filled with supercritical carbon dioxide. After the ASES process was repeated, precipitates of the ternary components were obtained by depressurizing the reaction vessel. When a methanolic solution of prednisolone/PEG 4000/SDS at a weight ratio of 1:6:2 was sprayed under the optimized ASES conditions, the mean particle size of prednisolone obtained after dispersing the precipitates in water was observed to be ca. 230 nm. Prednisolone nanoparticles were not obtained by the binary ASES process for prednisolone, in the presence of either PEG or SDS. Furthermore, ternary cryogenic cogrinding, as well as solvent evaporation, was not effective for the preparation of prednisolone nanoparticles. As the ASES process can be conducted under moderate temperature conditions, the ASES process that was applied to the ternary system appeared to be one of the most promising methods for the preparation of drug nanoparticles using the multicomponent system.

  20. Analysis of hollow fibre membrane systems for multicomponent gas separation

    KAUST Repository

    Khalilpour, Rajab

    2013-02-01

    This paper analysed the performance of a membrane system over key design/operation parameters. A computation methodology is developed to solve the model of hollow fibre membrane systems for multicomponent gas feeds. The model represented by a nonlinear differential algebraic equation system is solved via a combination of backward differentiation and Gauss-Seidel methods. Natural gas sweetening problem is investigated as a case study. Model parametric analyses of variables, namely feed gas quality, pressure, area, selectivity and permeance, resulted in better understanding of operating and design optima. Particularly, high selectivities and/or permeabilities are shown not to be necessary targets for optimal operation. Rather, a medium selectivity (<60 in the given example) combined with medium permeance (∼300-500×10-10mol/sm2Pa in the given case study) is more advantageous. This model-based membrane systems engineering approach is proposed for the synthesis of efficient and cost-effective multi-stage membrane networks. © 2012 The Institution of Chemical Engineers.

  1. Multi-component separation and analysis of bat echolocation calls.

    Science.gov (United States)

    DiCecco, John; Gaudette, Jason E; Simmons, James A

    2013-01-01

    The vast majority of animal vocalizations contain multiple frequency modulated (FM) components with varying amounts of non-linear modulation and harmonic instability. This is especially true of biosonar sounds where precise time-frequency templates are essential for neural information processing of echoes. Understanding the dynamic waveform design by bats and other echolocating animals may help to improve the efficacy of man-made sonar through biomimetic design. Bats are known to adapt their call structure based on the echolocation task, proximity to nearby objects, and density of acoustic clutter. To interpret the significance of these changes, a method was developed for component separation and analysis of biosonar waveforms. Techniques for imaging in the time-frequency plane are typically limited due to the uncertainty principle and interference cross terms. This problem is addressed by extending the use of the fractional Fourier transform to isolate each non-linear component for separate analysis. Once separated, empirical mode decomposition can be used to further examine each component. The Hilbert transform may then successfully extract detailed time-frequency information from each isolated component. This multi-component analysis method is applied to the sonar signals of four species of bats recorded in-flight by radiotelemetry along with a comparison of other common time-frequency representations.

  2. Ion Bernstein wave heating in a multi-component plasma

    International Nuclear Information System (INIS)

    Puri, S.

    1980-10-01

    Conditions for the coupling and absorption of Gross-Bernstein ion-cyclotron waves in a multi-component plasma are examined. Two cases are distinguished depending upon whether, the antenna initially launches, (i) the quasi-torsional slow electromagnetic wave with azimuthal magnetic field (TM) polarization, or (ii) the quasi-compressional fast wave with the electric field oriented azimuthally (TE). Analytic expressions for the plasma surface impedance are derived taking into account the pertinent warm plasma modifications near the vacuum-plasma interface. Antenna configurations capable of efficient coupling of the radio frequency energy to these modes are studied. A method for simulating waveguide like launching using transmission lines is pointed out. It is found that impurity concentrations exceeding a few parts in a thousand are capable of competing with the bulk ions in the energy absorption processes; this could lead to energy deposition near the plasma edge. Measures for avoiding edge heating problems by a careful choice of parameters e.g. restricting the heating frequency to the fundamental ion gyrofrequency are outlined. Equal care is to be exercised in limiting the nsub(z) spectrum to low discrete values in order to avoid the potentially dangerous problem of runaway electron heating. (orig.)

  3. Multicomponent Treatment of Rapid Naming, Reading Rate, and Visual Attention in Single and Double Deficit Dyslexics

    Science.gov (United States)

    Johnson, Kary A.

    2013-01-01

    While the relationship between rapid automatic naming (RAN) deficiencies and dyslexia (reading disability) is well developed and supported in the behavioral and medical research literature to date, direct treatment of the specific RAN deficiency in addition to subsequently poor reading outcomes in the lexical skill of reading rate and the…

  4. Exposure to diesel exhaust fumes in the context of exposure to ultrafine particles

    Directory of Open Access Journals (Sweden)

    Stella Bujak-Pietrek

    2016-08-01

    Full Text Available Objectives: Diesel exhaust fumes emission is a significant source of ultrafine particles, the size of which is expressed in nanometers. People occupationally exposed to diesel exhaust particles include mainly workers servicing vehicles with engines of this type. This article presents the analysis of measurements of ultrafine particle concentrations occurring in the bus depot premises during the work connected with everyday technical servicing of buses. Material and Methods: The measurements were carried out in the everyday servicing (ES room of the bus depot before, during and after the work connected with bus servicing. Determinations included: particle concentrations in terms of particle number and particle surface area, and mass concentrations of aerosol. Results: Mean value of number concentration of 10- to 1000-nm particles increased almost 20-fold, from 7600 particles/cm3 before starting bus servicing procedures to 130 000 particles/cm3 during the bus servicing procedures in the room. During the procedures, the mean surface area concentration of particles potentially deposited in the alveolar (A region was almost 3 times higher than that of the particles depositing in the tracheo-bronchial (TB region: 356.46 μm2/cm3 vs. 95.97 μm2/cm3, respectively. The mass concentration of the fraction of particulate matter with aerodynamic diameter 0.02–1 μm (PM1 increased 5-fold during the analyzed procedures and was 0.042 mg/m3 before, and 0.298 mg/m3 while the procedures continued. Conclusions: At the time when bus servicing procedures continued in the ES room, a very high increase in all parameters of the analyzed particles was observed. The diesel exhaust particles exhibit a very high degree of fragmentation and, while their number is very high and their surface area is very large, their mass concentration is relatively low. The above findings confirm that ultrafine particles found in diesel exhaust fumes may be harmful to the health of the

  5. Development of land-use regression models for exposure assessment to ultrafine particles in Rome, Italy

    Science.gov (United States)

    Cattani, Giorgio; Gaeta, Alessandra; di Menno di Bucchianico, Alessandro; de Santis, Antonella; Gaddi, Raffaela; Cusano, Mariacarmela; Ancona, Carla; Badaloni, Chiara; Forastiere, Francesco; Gariazzo, Claudio; Sozzi, Roberto; Inglessis, Marco; Silibello, Camillo; Salvatori, Elisabetta; Manes, Fausto; Cesaroni, Giulia; The Viias Study Group

    2017-05-01

    The health effects of long-term exposure to ultrafine particles (UFPs) are poorly understood. Data on spatial contrasts in ambient ultrafine particles (UFPs) concentrations are needed with fine resolution. This study aimed to assess the spatial variability of total particle number concentrations (PNC, a proxy for UFPs) in the city of Rome, Italy, using land use regression (LUR) models, and the correspondent exposure of population here living. PNC were measured using condensation particle counters at the building facade of 28 homes throughout the city. Three 7-day monitoring periods were carried out during cold, warm and intermediate seasons. Geographic Information System predictor variables, with buffers of varying size, were evaluated to model spatial variations of PNC. A stepwise forward selection procedure was used to develop a "base" linear regression model according to the European Study of Cohorts for Air Pollution Effects project methodology. Other variables were then included in more enhanced models and their capability of improving model performance was evaluated. Four LUR models were developed. Local variation in UFPs in the study area can be largely explained by the ratio of traffic intensity and distance to the nearest major road. The best model (adjusted R2 = 0.71; root mean square error = ±1,572 particles/cm³, leave one out cross validated R2 = 0.68) was achieved by regressing building and street configuration variables against residual from the "base" model, which added 3% more to the total variance explained. Urban green and population density in a 5,000 m buffer around each home were also relevant predictors. The spatial contrast in ambient PNC across the large conurbation of Rome, was successfully assessed. The average exposure of subjects living in the study area was 16,006 particles/cm³ (SD 2165 particles/cm³, range: 11,075-28,632 particles/cm³). A total of 203,886 subjects (16%) lives in Rome within 50 m from a high traffic road and they

  6. Soot, unburned carbon and ultrafine particle emissions from air- and oxy-coal flames

    International Nuclear Information System (INIS)

    Morris, W.J.; Yu, Dunxi; Wendt, J.O.L.

    2010-01-01

    Oxy-coal combustion is one possible solution for the mitigation of greenhouse gases. In this process coal is burned in oxygen, rather than air, and the temperatures in the boiler are mitigated by recycling flue gases, so that the inlet mixture may contain either 27 % O 2 to match adiabatic flame temperatures, or 32 % O 2 to match gaseous radiation heat fluxes in the combustion chamber. However, a major issue for heat transfer from coal combustion is the radiative heat transmission from soot. For this research, air and oxy coal firing were compared regarding the emission of soot. A 100 kW down-fired laboratory combustor was used to determine effects of switching from air to oxy-firing on soot, unburned carbon and ultrafine particle emissions from practical pulverized coal flames. Of interest here were potential chemical effects of substitution of the N 2 in air by CO 2 in practical pulverized coal flames. The oxy-coal configuration investigated used once-through CO 2 , simulating cleaned flue gas recycle with all contaminants and water removed. Three coals were each burned in: a) air, b) 27 % O 2 / 73 % CO 2 , c) 32 % O 2 / 68 % CO 2 . Tests were conducted at (nominally) 3 %, 2 %, 1 % and 0 % O 2 in the exhaust (dry basis). For each condition, particulate samples were iso kinetically withdrawn far from the radiant zone, and analyzed using a photoacoustic analyzer (PA) for black carbon, a scanning mobility particle sizer (SMPS) for ultrafine particles, and a total sample loss on ignition (LOI) method for unburned carbon in ash. Data suggest that at low stoichiometric ratios, ultrafine particles consist primarily of black carbon, which, for the bituminous coal, is produced in lesser amounts under oxy-fired conditions than under the air-fired condition, even when adiabatic flame temperatures are matched. However, significant changes in mineral matter vaporization were not observed unless the flames were hotter. These and other results are interpreted in the light of

  7. Evaluating the flow processes in ultrafine-grained materials at elevated temperatures

    Directory of Open Access Journals (Sweden)

    Megumi Kawasaki

    2013-06-01

    Full Text Available When polycrystalline materials are tested in tension at elevated temperatures, the flow mechanisms depend upon various parameters including the temperature of testing, the applied stress and the material grain size. The plotting of deformation mechanism maps is a procedure used widely in displaying and interpreting the creep properties of conventional coarse-grained metals but there have been few attempts to date to use this same procedure for ultrafine-grained and nanocrystalline materials produced through the application of severe plastic deformation (SPD. This report examines the potential for using deformation mechanism mapping for materials processed by SPD and presents examples for materials processed using equal-channel angular pressing and high-pressure torsion.

  8. Enhanced superplastic deformation behavior of ultrafine-grained Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Saitova, L.; Hoeppel, H.W.; Goeken, M. [Department of Materials Science and Engineering, Universitaet Erlangen-Nuernberg, Erlangen (Germany); Semenova, I.; Valiev, R. [Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, Ufa (Russian Federation)

    2008-04-15

    The mechanical behavior of the Ti-6Al-4V ELI alloy in both conventional grain size (CG) and ultrafine-grained (UFG) conditions under tension and compression at elevated temperatures (500-800 C) is considered. Grain refinement by equal-channel angular pressing (ECAP) followed by multicycle extrusion was observed to result in a considerable improvement of superplastic characteristics of Ti-6Al-4V ELI alloy. The alloy exhibits a superplastic deformation behavior already at 600 C. The enhanced regime of superplasticity allows more efficient forming of parts and components. In addition, the UFG microstructure and, consequently, enhanced mechanical properties are kept after superplastic forming. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  9. Immersed friction stir welding of ultrafine grained accumulative roll-bonded Al alloy

    International Nuclear Information System (INIS)

    Hosseini, M.; Danesh Manesh, H.

    2010-01-01

    In this research, ultrafine grained strips of commercial pure strain hardenable aluminum (AA1050) were produced by accumulative roll-bonding (ARB) technique. These strips were joined by friction stir welding (FSW) in immersed (underwater) and conventional (in-air) conditions to investigate the effect of the immersion method on the microstructure and mechanical properties of the joint, aiming to reduce the deterioration of the mechanical properties of the joint. Transmission electron microscopy and X-ray diffraction analyses were used to evaluate the microstructure, showing smaller grains and subgrains in the stir zone of the immersed FSW condition with respect to the conventional FSW method. The hardness and tensile properties of the immersed friction stir welded sample and ARBed base metal show more similarity compared to the conventional friction stir welded sample. Moreover, the aforementioned method can result in the enhancement of the superplasticity tendency of the material.

  10. Synthesis and photoelectric properties of cadmium hydroxide and cadmium hydroxide/cadmium sulphide ultrafine nanowires

    Science.gov (United States)

    Dou, Baoli; Jiang, Xiaohong; Wang, Xiaohong; Tang, Liping; Du, Zuliang

    2017-07-01

    Cd(OH)2 ultrafine nanowires with a high aspect ratio were fabricated by the hydrothermal method and were subsequently used as a sacrificial template to generate Cd(OH)2/CdS nanowires. The transmission electron microscopy results show that the length of the nanowires reached several micrometres, and the diameter of the nanowires was approximately 10-20.0 nm. The charge transport properties of the Cd(OH)2 and Cd(OH)2/CdS nanowires assembled on comb Au electrodes was also investigated. The I-V results showed that the current intensity of the Cd(OH)2/CdS nanowires was increased by four orders of magnitude compared with the Cd(OH)2 nanowires, achieving 10-10A.

  11. Filtration efficiency of an electrostatic fibrous filter: Studying filtration dependency on ultrafine particle exposure and composition

    DEFF Research Database (Denmark)

    Ardkapan, Siamak Rahimi; Johnson, Matthew S.; Yazdi, Sadegh

    2014-01-01

    The objective of the present study is to investigate the relationship between ultrafine particle concentrations and removal efficiencies for an electrostatic fibrous filter in a laboratory environment. Electrostatic fibrous filters capture particles efficiently, with a low pressure drop. Therefore...... they have applications in building ventilation systems. The relationship between particle removal efficiency and particle concentration has not been widely investigated in ventilation systems and indoor environments. In order to achieve the objective of this study, experiments were performed in a controlled...... laboratory environment using two different particle counters: a Scanning Mobility Particle Sizer and a NanoTracer. Particles were generated at different concentrations by burning a pure wax candle in a test room. The set-up consisted of a test room, a fan a duct and the particle filter. The results show...

  12. Synthesis and Mechanical Characterisation of an Ultra-Fine Grained Ti-Mg Composite

    Directory of Open Access Journals (Sweden)

    Markus Alfreider

    2016-08-01

    Full Text Available The importance of lightweight materials such as titanium and magnesium in various technical applications, for example aerospace, medical implants and lightweight construction is well appreciated. The present study is an attempt to combine and improve the mechanical properties of these two materials by forming an ultra-fine grained composite. The material, with a composition of 75 vol% (88.4 wt% Ti and 25 vol% (11.4 wt% Mg , was synthesized by powder compression and subsequently deformed by high-pressure torsion. Using focused ion beam machining, miniaturised compression samples were prepared and tested in-situ in a scanning electron microscope to gain insights into local deformation behaviour and mechanical properties of the nanocomposite. Results show outstanding yield strength of around 1250 MPa, which is roughly 200 to 500 MPa higher than literature reports of similar materials. The failure mode of the samples is accounted for by cracking along the phase boundaries.

  13. Room temperature deformation mechanisms in ultrafine-grained materials processed by hot isostatic pressing

    International Nuclear Information System (INIS)

    Cao, W.Q.; Dirras, G.F.; Benyoucef, M.; Bacroix, B.

    2007-01-01

    Ultrafine-grained (uf-g) and microcrystalline-grained (mc-g) irons have been fabricated by hot isostatic pressing of nanopowders. The mechanical properties have been characterized by compressive tests at room temperature and the resulting microstructures and textures have been determined by combining electron back scatter diffraction and transmission electron microscopy. A transition of the deformation mode, from work hardening to work softening occurs for grain sizes below ∼1 μm, reflecting a transition of the deformation mode from homogeneous to localized deformation into shear bands (SBs). The homogeneous deformation is found to be lattice dislocation-based while the deformation within SBs involves lattice dislocations as well as boundary-related mechanisms, possibly grain boundary sliding accommodated by boundary opening

  14. Deformation Structure of Unidirectionally Compressed Ultrafine-Grained Mg-3Al-1Zn Alloy

    Science.gov (United States)

    Lee, W. T.; Ding, S. X.; Sun, D. K.; Hsiao, C. I.; Chang, C. P.; Chang, L.; Kao, P. W.

    2011-09-01

    Ultrafine-grained (UFG) Mg-3Al-1Zn (AZ31) alloys with gain sizes ranging from 0.46 to 3.22 μm were prepared by equal channel angular pressing (ECAP) and annealing. The deformation structure of UFG AZ31 alloy resulting from uniaxial compression was studied by optical and electron microscopy. The deformation was noted to proceed with the development of shear bands (SBs), which has not been reported in an UFG hcp metal. Characterization of these SBs was performed, and comparison with the SBs formed in UFG bcc and fcc metals was given. \\{ 10bar{1}2\\} tension twins inside SBs were found in all specimens compressed, irrespective of the grain size. Discussion on the limiting grain size of twinning in the UFG AZ31 alloy is also given.

  15. Strain rate sensitivity of ultrafine-grained Al and Al-Mg-alloys

    Energy Technology Data Exchange (ETDEWEB)

    Boehner, Andreas; May, Johannes; Hoeppel, Heinz Werner; Goeken, Mathias [Institute I: General Materials Properties, Department of Materials Science and Engineering, University of Erlangen-Nuernberg (Germany); Vevecka-Priftaj, Aferdita [Department of Physics, Polytechnic University of Tirana (Albania)

    2008-07-01

    Nanocrystalline or ultrafine-grained (UFG) metals are known to exhibit very high strength paired with high ductility. In this context, strain rate sensitivity (SRS) is regarded to be the main issue to explain this behaviour. Bulk UFG metals can be achieved by Equal Channel Angular Pressing (ECAP), where the material is deformed by repeated shear deformation. In this contribution, detailed investigations of the SRS of technically pure Al, AlMg and a technologically relevant Al-Mg-alloy (AA6061) were performed. For the precipitation hardenable AA6061-alloy a solution treated and a peak aged state were investigated. The SRS was determined by strain rate jump compression tests which were performed in a temperature range from room temperature (RT) up to 250 C. It could be shown that an UFG microstructure significantly enhances the SRS, especially at elevated temperatures. The influences of precipitations, microstructure and number of ECAP passes on the SRS and the mechanical properties are also discussed.

  16. Separation of Fischer-Tropsch Wax Products from Ultrafine Iron Catalyst Particles

    Energy Technology Data Exchange (ETDEWEB)

    Amitava Sarkar; James K. Neathery; Burtron H. Davis

    2006-12-31

    A fundamental filtration study was started to investigate the separation of Fischer-Tropsch Synthesis (FTS) liquids from iron-based catalyst particles. Slurry-phase FTS in slurry bubble column reactor systems is the preferred mode of operation since the reaction is highly exothermic. Consequently, heavy wax products in one approach may be separated from catalyst particles before being removed from the reactor system. Achieving an efficient wax product separation from iron-based catalysts is one of the most challenging technical problems associated with slurry-phase iron-based FTS and is a key factor for optimizing operating costs. The separation problem is further compounded by attrition of iron catalyst particles and the formation of ultra-fine particles.

  17. Unconfined twist : a simple method to prepare ultrafine grained metallic materials.

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Y. (Yonghao); Liao, Xiaozhou; Zhu, Y. T. (Yuntian Theodore)

    2004-01-01

    A new simple method - unconfined twist was employed to prepare ultrafine grained (UFG) Fe,wire. A coarse grained (CG) Fe wire with a diameter of 0.85 mm was fixed at one end, and twisted at the other end. After maximum twist before fracture, in the cross-sectional plane, concentrically deformed layers with a width of several micrometers formed surrounding the center axis of the wire. The near-surface deformed layers consist of lamella grains with a width in submicrometer range. In the longitudinal plane, deformed bands (with a width of several micrometers) formed uniformly, which were composed of lamella crystallites (with a width in submicrometer range). The tensile yield strength and ultimate strength of the twisted Fe wire are increased by about 150% and 100% compared with the values of its CG counterpart.

  18. Severe plastic deformation for obtaining nanometric and ultrafine-grained materials

    Directory of Open Access Journals (Sweden)

    Rodolfo Rodríguez Baracaldo

    2007-01-01

    Full Text Available The aim of this paper is to provide a general overview of nanocrystalline and ultra-fine grain material production using severe plastic deformation (SPD, this being one of the most active research fields in the mechanical processing of materials. The paper gives an explanation of the more important SPD techniques (mechanical milling, equal channel angular pressing, high pressure torsion, extrusion-compression and accumulated roll-bond as regards fundamental principles, advantages and limitations. Some experimental results for iron and copper obtained by this paper’s authors are attached. These materials’ great potential is shown in several fields of use, especially in the aerospace industry. Current research prospects are also referred to in terms of structural and mechanical behaviour and the development of large-scale industrial processing.

  19. Personal exposure to airborne ultrafine particles in the urban area of Milan

    International Nuclear Information System (INIS)

    Cattaneo, A; Garramone, G; Taronna, M; Peruzzo, C; Cavallo, D M

    2009-01-01

    The relevance of health effects related to ultrafine particles (UFPs; aerodynamic diameter 5 particles/cm 3 . UFPs measures were divided on the basis of crossed environments or micro-environments, days of the week and day time (hours). The highest measured mean concentrations and data variability were observed during walking time and moving on motorized vehicles (bus and car), indicating that the highest exposure to UFPs can be reached near motorized traffic. The lowest exposures were observed in green areas and in office microenvironments. An appreciable difference between working and non-working days was observed. Concentration patterns and variation by days of the week and time periods appears related to time trends in traffic intensity.

  20. Possible Gems and Ultra-Fine Grained Polyphase Units in Comet Wild 2.

    Science.gov (United States)

    Gainsforth, Z.; Butterworth, A. L.; Jilly-Rehak, C. E.; Westphal, A. J.; Brownlee, D. E.; Joswiak, D.; Ogliore, R. C.; Zolensky, M. E.; Bechtel, H. A.; Ebel, D. S.; hide

    2016-01-01

    GEMS and ultrafine grained polyphase units (UFG-PU) in anhydrous IDPs are probably some of the most primitive materials in the solar system. UFG-PUs contain nanocrystalline silicates, oxides, metals and sulfides. GEMS are rounded approximately 100 nm across amorphous silicates containing embedded iron-nickel metal grains and sulfides. GEMS are one of the most abundant constituents in some anhydrous CPIDPs, often accounting for half the material or more. When NASA's Stardust mission returned with samples from comet Wild 2 in 2006, it was thought that UFG-PUs and GEMS would be among the most abundant materials found. However, possibly because of heating during the capture process in aerogel, neither GEMS nor UFG-PUs have been clearly found.

  1. On tension-compression asymmetry in ultrafine-grained and nanocrystalline metals

    KAUST Repository

    Gurses, Ercan

    2010-12-01

    We present a physically motivated computational study explaining the tension/compression (T/C) asymmetry phenomenon in nanocrystalline (nc) and ultrafine-grained (ufg) face centered cubic (fcc) metals utilizing a variational constitutive model where the nc-metal is modeled as a two-phase material consisting of a grain interior phase and a grain boundary affected zone (GBAZ). We show that the existence of voids and their growth in GBAZ renders the material pressure sensitivity due to porous plasticity and that the utilized model provides a physically sound mechanism to capture the experimentally observed T/C asymmetry in nc- and ufg-metals. © 2010 Elsevier B.V. All rights reserved.

  2. Ultrafine polybenzimidazole (PBI) fibers. [separators for alkaline batteries and dfuel cells

    Science.gov (United States)

    Chenevey, E. C.

    1979-01-01

    Mats were made from ultrafine polybenzimidazole (PBI) fibers to provide an alternate to the use of asbestos as separators in fuel cells and alkaline batteries. To minimize distortion during mat drying, a process to provide a dry fibrid was developed. Two fibrid types were developed: one coarse, making mats for battery separators; the other fine, making low permeability matrices for fuel cells. Eventually, it was demonstrated that suitable mat fabrication techniques yielded fuel cell separators from the coarser alkaline battery fibrids. The stability of PBI mats to 45% KOH at 123 C can be increased by heat treatment at high temperatures. Weight loss data to 1000 hours exposure show the alkali resistance of the mats to be superior to that of asbestos.

  3. Exposure to Ultrafine Particles from Ambient Air and Oxidative Stress-Induced DNA Damage

    DEFF Research Database (Denmark)

    Bräuner, Elvira Vaclavik; Forchhammer, Lykke; Møller, Peter

    2007-01-01

    exercise for 180 min and with exposure to particles (NC 6169-15362/cm3) or filtered air (NC 91-542/cm3) for 24 hr. METHODS: The levels of DNA strand breaks (SBs), oxidized purines as formamidopyrimidine DNA glycolase (FPG) sites, and activity of 7,8-dihydro-8-oxoguanine-DNA glycosylase (OGG1) in PBMCs were......BACKGROUND: Particulate matter, especially ultrafine particles (UFPs), may cause health effects through generation of oxidative stress, with resulting damage to DNA and other macromolecules. OBJECTIVE: We investigated oxidative damage to DNA and related repair capacity in peripheral blood...... mononuclear cells (PBMCs) during controlled exposure to urban air particles with assignment of number concentration (NC) to four size modes with average diameters of 12, 23, 57, and 212 nm. DESIGN. Twenty-nine healthy adults participated in a randomized, two-factor cross-over study with or without biking...

  4. Sliding wear characteristics of ultrafine-grained non-strain-hardening aluminum-magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y.S.; Ha, J.S. [School of Advanced Materials Engineering, Kookmin Univ., Seoul (Korea); Shin, D.H. [Dept. of Metallurgy and Materials Science, Hanyang Univ., Ansan (Korea)

    2005-07-01

    Coarse grains of commercial 5052 Al and 5083 Al alloys were refined by the accumulative roll bonding (ARB) process. Average grain size of the refined microstructure was 200 nm. The 5083 Al alloy that has higher Mg content required more deformation for the refinement. Dry sliding wear behavior of the ultra-fine grained (UFG) Al alloys was investigated using a pin-on-disk wear tester at room temperature. The UFG microstructure of the processed alloys hardly increased the wear resistance of the Al alloys in spite of the increased strength and hardness. Wear rate of the UFG Al alloys was higher than that of the non-processed coarse-grained starting alloys. The SEM observation of worn surfaces revealed that surface deformation controlled the wear. The low wear resistance of the UFG Al alloys was attributed to non-equilibrium and unstable grain boundaries and low strain hardening capability of the alloys. (orig.)

  5. The importance of fracture toughness in ultrafine and nanocrystalline bulk materials.

    Science.gov (United States)

    Pippan, R; Hohenwarter, A

    2016-07-02

    The suitability of high-strength ultrafine and nanocrystalline materials processed by severe plastic deformation methods and aimed to be used for structural applications will strongly depend on their resistance against crack growth. In this contribution some general available findings on the damage tolerance of this material class will be summarized. Particularly, the occurrence of a pronounced fracture anisotropy will be in the center of discussion. In addition, the great potential of this generated anisotropy to obtain high-strength materials with exceptionally high fracture toughness in specific loading and crack growth directions will be enlightened. IMPACT STATEMENT Severely plastically deformed materials are reviewed in light of their damage tolerance. The frequently observed toughness anisotropy allows unprecedented fracture toughness - strength combinations.

  6. Colossal magnetoelectric effect in 3-1 multiferroic nanocomposites originating from ultrafine nanodomain structures

    Science.gov (United States)

    Van Lich, Le; Shimada, Takahiro; Miyata, Kohei; Nagano, Koyo; Wang, Jie; Kitamura, Takayuki

    2015-12-01

    We investigate colossal magnetoelectric coupling through interactions between ferroelectric and ferromagnetic nanodomains in 3-1 multiferroic BaTiO3/CoFe2O4 nanocomposites using a recent real-space phase field model based on the Landau-Ginzburg theory. A hierarchical ultrafine domain structure is characteristically formed in the nanocomposites, resulting in an extremely high density of domain walls, which causes polarization domains to be more susceptible to an external magnetic field via interfacial strain-mediation. This leads to an anomalously large magnetoelectric coupling effect in the multiferroic nanocomposites. We further demonstrate that the domain configuration and consequent magnetoelectric effect are strongly dependent on the constituent phase distribution, suggesting a promising route for the rational design of multiferroic domains and magnetoelectric effects, reminiscent of recent nano-metamaterial concepts.

  7. Cyclic stress-strain response and low-cycle fatigue damage in ultrafine grained copper

    International Nuclear Information System (INIS)

    Maier, H.J.; Gabor, P.; Karaman, I.

    2005-01-01

    We report on the fatigue behavior of ultrafine grained (UFG) copper obtained by equal channel angular extrusion (ECAE). Cyclic stress-strain response and fatigue life data were determined in fatigue tests conducted in the low-cycle fatigue (LCF) regime. The early stages of the fatigue process were examined in a scanning electron microscope equipped with a small-scale load frame that allowed for in situ fatigue observations. The ECAE route 16E gives superior fatigue performances as it provides for stable cyclic stress-strain response and more homogeneous plastic deformation than routes that are composed of lower number of ECAE passes. Still, the in situ fatigue tests indicated that fatigue damage occurs on a very localized scale, and thus, additional strengthening mechanisms need to be exploited to obtain UFG materials that display enhanced microstructural stability

  8. Source apportionment of ultrafine and fine particle concentrations in Brisbane, Australia.

    Science.gov (United States)

    Friend, Adrian J; Ayoko, Godwin A; Jayaratne, E Rohan; Jamriska, Milan; Hopke, Philip K; Morawska, Lidia

    2011-08-01

    To investigate the significance of sources around measurement sites, assist the development of control strategies for the important sources and mitigate the adverse effects of air pollution due to particle size. In this study, sampling was conducted at two sites located in urban/industrial and residential areas situated at roadsides along the Brisbane Urban Corridor. Ultrafine and fine particle measurements obtained at the two sites in June-July 2002 were analysed by positive matrix factorization. Six sources were present, including local traffic, two traffic sources, biomass burning and two currently unidentified sources. Secondary particles had a significant impact at site 1, while nitrates, peak traffic hours and main roads located close to the source also affected the results for both sites. This significant traffic corridor exemplifies the type of sources present in heavily trafficked locations and future attempts to control pollution in this type of environment could focus on the sources that were identified.

  9. High Temperature Flow Response Modeling of Ultra-Fine Grained Titanium

    Directory of Open Access Journals (Sweden)

    Seyed Vahid Sajadifar

    2015-07-01

    Full Text Available This work presents the mechanical behavior modeling of commercial purity titanium subjected to severe plastic deformation (SPD during post-SPD compression, at temperatures of 600-900 °C and at strain rates of 0.001-0.1 s−1. The flow response of the ultra-fine grained microstructure is modeled using the modified Johnson-Cook model as a predictive tool, aiding high temperature forming applications. It was seen that the model was satisfactory at all deformation conditions except for the deformation temperature of 600 °C. In order to improve the predictive capability, the model was extended with a corrective term for predictions at temperatures below 700 °C. The accuracy of the model was displayed with reasonable agreement, resulting in error levels of less than 5% at all deformation temperatures.

  10. Respiratory health effects of ultrafine and fine particle exposure in cyclists.

    Science.gov (United States)

    Strak, Maciej; Boogaard, Hanna; Meliefste, Kees; Oldenwening, Marieke; Zuurbier, Moniek; Brunekreef, Bert; Hoek, Gerard

    2010-02-01

    Monitoring studies have shown that commuters are exposed to high air pollution concentrations, but there is limited evidence of associated health effects. We carried out a study to investigate the acute respiratory health effects of air pollution related to commuting by bicycle. Twelve healthy adults cycled a low- and a high-traffic intensity route during morning rush hour in Utrecht, The Netherlands. Exposure to traffic-related air pollution was characterised by measurements of PM(10), soot and particle number. Before, directly after and 6 h after cycling we measured lung function (FEV(1), FVC, PEF), exhaled NO (FE(NO)) and respiratory symptoms. The association between post- minus pre-exposure difference in health effects and exposure during cycling was evaluated with linear regression models. The average particle number concentration was 59% higher, while the average soot concentration was 39% higher on the high-traffic route than on the low-traffic route. There was no difference for PM(10). Contrary to our hypothesis, associations between air pollution during cycling and lung function changes immediately after cycling were mostly positive. Six hours after cycling, associations between air pollution exposure and health were mostly negative for lung function changes and positive for changes in exhaled NO, although non-significant. We found substantial differences in ultrafine particle number and soot exposure between two urban cycling routes. Exposure to ultrafine particles and soot during cycling was weakly associated with increased exhaled NO, indicative of airway inflammation, and decrements in lung function 6 h after exposure. A limitation of the study was the relatively small sample size.

  11. Variability in exposure to ambient ultrafine particles in urban schools: Comparative assessment between Australia and Spain.

    Science.gov (United States)

    Mazaheri, Mandana; Reche, Cristina; Rivas, Ioar; Crilley, Leigh R; Álvarez-Pedrerol, Mar; Viana, Mar; Tobias, Aurelio; Alastuey, Andrés; Sunyer, Jordi; Querol, Xavier; Morawska, Lidia

    2016-03-01

    Ambient ultrafine particle number concentrations (PNC) have inhomogeneous spatio-temporal distributions and depend on a number of different urban factors, including background conditions and distant sources. This paper quantitatively compares exposure to ambient ultrafine particles at urban schools in two cities in developed countries, with high insolation climatic conditions, namely Brisbane (Australia) and Barcelona (Spain). The analysis used comprehensive indoor and outdoor air quality measurements at 25 schools in Brisbane and 39 schools in Barcelona. PNC modes were analysed with respect to ambient temperature, land use and urban characteristics, combined with the measured elemental carbon concentrations, NOx (Brisbane) and NO2 (Barcelona). The trends and modes of the quantified weekday average daily cycles of ambient PNC exhibited significant differences between the two cities. PNC increases were observed during traffic rush hours in both cases. However, the mid-day peak was dominant in Brisbane schools and had the highest contribution to total PNC for both indoors and outdoors. In Barcelona, the contribution from traffic was highest for ambient PNC, while the mid-day peak had a slightly higher contribution for indoor concentrations. Analysis of the relationships between PNC and land use characteristics in Barcelona schools showed a moderate correlation with the percentage of road network area and an anti-correlation with the percentage of green area. No statistically significant correlations were found for Brisbane. Overall, despite many similarities between the two cities, school-based exposure patterns were different. The main source of ambient PNC at schools was shown to be traffic in Barcelona and mid-day new particle formation in Brisbane. The mid-day PNC peak in Brisbane could have been driven by the combined effect of background and meteorological conditions, as well as other local/distant sources. The results have implications for urban development

  12. Effects of exposure to ambient ultrafine particles on respiratory health and systemic inflammation in children.

    Science.gov (United States)

    Clifford, Sam; Mazaheri, Mandana; Salimi, Farhad; Ezz, Wafaa Nabil; Yeganeh, Bijan; Low-Choy, Samantha; Walker, Katy; Mengersen, Kerrie; Marks, Guy B; Morawska, Lidia

    2018-03-04

    It is known that ultrafine particles (UFP, particles smaller than 0.1 μm) can penetrate deep into the lungs and potentially have adverse health effects. However, epidemiological data on the health effects of UFP is limited. Therefore, our objective was to test the hypothesis that exposure to UFPs is associated with respiratory health status and systemic inflammation among children aged 8 to 11 years. We conducted a cross-sectional study among 655 children (43.3% male) attending 25 primary (elementary) schools in the Brisbane Metropolitan Area, Australia. Ultrafine particle number concentration (PNC) was measured at each school and modelled at homes using Land Use Regression to derive exposure estimates. Health outcomes were respiratory symptoms and diagnoses, measured by parent-completed questionnaire, spirometric lung function, exhaled nitric oxide (FeNO), and serum C reactive protein (CRP). Exposure-response models, adjusted for potential personal and environmental confounders measured at the individual, home and school level, were fitted using Bayesian methods. PNC was not independently associated with respiratory symptoms, asthma diagnosis or spirometric lung function. However, PNC was positively associated with an increase in CRP (1.188-fold change per 1000 UFP cm -3 day/day (95% credible interval 1.077 to 1.299)) and an increase in FeNO among atopic participants (1.054 fold change per 1000 UFP cm -3 day/day (95% CrI 1.005 to 1.106)). UFPs do not affect respiratory health outcomes in children but do have systemic effects, detected here in the form of a positive association with a biomarker for systemic inflammation. This is consistent with the known propensity of UFPs to penetrate deep into the lung and circulatory system. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Electromagnetic wave absorption properties of composites with ultrafine hollow magnetic fibers

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Jin Woo [Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (BK21 Granted Program), 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of); Composites Research Center, Korea Institute of Materials Science, 66 Sang-nam-dong, Changwon, Gyeongnam (Korea, Republic of); Lee, Sang Bok; Kim, Jin Bong; Lee, Sang Kwan [Composites Research Center, Korea Institute of Materials Science, 66 Sang-nam-dong, Changwon, Gyeongnam (Korea, Republic of); Park, O Ok, E-mail: oopark@kaist.ac.kr [Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (BK21 Granted Program), 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of); Department of Energy Systems Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), 50-1, Sang-ri, Hyeongpung-myeon, Dalseong-gun, Daegu 711-873 (Korea, Republic of)

    2014-06-01

    Ultrafine hollow magnetic fibers were prepared by electroless plating using hydrolyzed polyester fiber as a sacrificial substrate. These hollow fibers can be served for lightweight and efficient electromagnetic (EM) absorbing materials. As observed from SEM and EDS analysis, hollow structures consisting of Ni inner layer and Fe or Fe–Co outer layer were obtained. By introducing Co onto Fe, oxidation of the Fe layer was successfully prevented making it possible to enhance the complex permeability compared to a case in which only Fe was used. Polymeric composites containing the hollow fibers with different weight fractions and fiber lengths were prepared by a simple mixing process. The electromagnetic wave properties of the composites were measured by a vector network analyzer and it was found that the hollow magnetic fibers show a clear resonance peak of the complex permittivity around the X-band range (8–12 GHz) and the resonance frequency strongly depends on the fiber concentration and length. A possible explanation for the unique resonance is that the hollow fibers possess relatively low electrical conductivity and a long mean free path due to their oxidized phase and hollow structure. The calculated EM wave absorption with the measured EM wave properties showed that the composite containing 30 wt% hollow Ni/Fe–Co (7:3) fibers in length of 180 μm exhibited multiple absorbance peaks resulting in a broad absorption bandwidth of 4.2 GHz. It is obvious that this multiple absorbance is attributed to the resonance characteristic of the composite. - Highlights: • The ultrafine hollow fibers consist of inner Ni layer (∼100 nm) and outer Fe or Fe–Co layer (500–700 nm). • Composites with the fibers show a high permittivity as well as permeability at low weight fractions (10–30 wt%). • The composites show a permittivity resonance and the resonance frequency can be controlled by fiber content and length. • The composite absorber exhibits a double

  14. A case study of exposure to ultrafine particles from secondhand tobacco smoke in an automobile.

    Science.gov (United States)

    Liu, S; Zhu, Y

    2010-10-01

    Secondhand tobacco smoke (SHS) in enclosed spaces is a major source of potentially harmful airborne particles. To quantify exposure to ultrafine particles (UFP) because of SHS and to investigate the interaction between pollutants from SHS and vehicular emissions, number concentration and size distribution of UFP and other air pollutants (CO, CO(2) , and PM(2.5)) were measured inside a moving vehicle under five different ventilation conditions. A major interstate freeway with a speed limit of 60 mph and an urban roadway with a speed limit of 30 mph were selected to represent typical urban routes. In a typical 30-min commute on urban roadways, the SHS of one cigarette exposed passengers to approximately 10 times the UFP and 120 times the PM(2.5) of ambient air. The most effective solution to protect passengers from SHS exposure is to abstain from smoking in the vehicle. Opening a window is an effective method for decreasing pollutant exposures on most urban roadways. However, under road conditions with high UFP concentrations, such as tunnels or busy freeways with high proportion of heavy-duty diesel trucks (such as the 710 Freeway in Los Angeles, CA, USA), opening a window is not a viable method to reduce UFPs. Time budget studies show that Americans spend, on average, more than 60 min each day in enclosed vehicles. Smoking inside vehicles can expose the driver and other passengers to high levels of pollutants. Thus, an understanding of the variations and interactions of secondhand tobacco smoke (SHS) and vehicular emissions under realistic driving conditions is necessary. Results of this study indicated that high ventilation rates can effectively dilute ultrafine particles (UFP) inside moving vehicles on urban routes. However, driving with open windows and an increased air exchange rate (AER) are not recommended on tunnels and heavily travelled freeways.

  15. Preparation and characterization of polycrystalline La2Zr2O7 ultrafine fibres via electrospinning.

    Science.gov (United States)

    Wang, Jinxian; Dong, Xiangting; Cui, Qizheng; Liu, Guixia; Yu, Wensheng

    2011-03-01

    Polyvinyl Pyrrolidone (PVP)/(Lanthanum nitrate and zirconium oxychloride) microfibres were fabricated by electrospinning. SEM micrographs indicated that the surface of the prepared composite microfibres was smooth, and the diameter of the microfibres was in the range of 2 microm-5 microm. X-ray diffractormetry (XRD) analysis revealed that the composite microfibres were amorphous in structure. La2Zr2O7 porous hollow ultrafine fibres (PHUF) were fabricated by calcination of the PVP/[La(NO3)3 + ZrOCl2] composite microfibres. The diameters of La2Zr2O7 PHUF were smaller than those of the PVP/[La(NO3)3 + ZrOCl2] composite microfibres. The surface of the ultrafine fibres became coarse with the increase of calcination temperatures. La2Zr2O7 PHUF formed by nanoparticles were acquired when calcination temperature was above 800 degrees C. Scanning electron microscope (SEM) analysis indicated that the diameter of the synthesized La2Zr2O7 PHUF was in the range of 500 nm-800 nm. XRD analysis revealed that the crystal structure of La2Zr2O7PHUF was found to be of the fluorite type when calcination temperature was 800 degrees C-900 degrees C, and of the pyrochlore type at 1000 degrees C. The latter is cubic in structure with space group Fd3m. The conductance of La2Zr2O7 PHUF is high to 5.19 S/cm2 and has no effect of frequency. Possible formation mechanism for La2Zr2O7 PHUF was preliminarily proposed.

  16. Performance of surface on ultrafine grained Ti-0.2Pd in simulated body fluid

    Science.gov (United States)

    Wang, Xiu-Lai; Zhou, Qing; Yang, Kai; Zou, Cheng-Hong; Wang, Lei

    2018-03-01

    Ti-0.2 wt% Pd (Ti-0.2Pd) which has high crevice corrosion resistance is highlighted for implant applications. In this work, Ti-0.2Pd alloy is subjected to equal channel angular pressing (ECAP) for grain refinement. The effect of the microstructure on the surface performance of Ti-0.2Pd in a simulated body fluid (SBF) adding bovine serum albumin is investigated. Heat-treated specimens including furnace cooled (FC) and water quenched (WQ) specimens are also prepared for comparison. The corrosion resistance is evaluated by the tests of potentiodynamic polarization and the measurement of electrochemical impedance spectroscopy (EIS). The composition and morphology of the surface after exposing to SBF 60 days were examined by X-ray photoelectronic spectroscopy (XPS), scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results show an ultrafine grained microstructure with average grain size of 3.6 μm is obtained after ECAP. The ultrafine grained Ti-0.2Pd has higher corrosion resistance than AR(as-received), WQ and FC specimens. The quantitative analysis of the surface shows larger numbers of precipitations formed on ECAPed Ti-0.2Pd than those formed on heat-treated. The precipitation contains more oxygen, calcium and phosphorus on ECAPed specimen than those on other specimens. The Ca:P ratio is ranged from 1:0.7 to 1:4.4, no dependent on the specimen type. A larger Warburg resistance is obtained on WQ specimen indicating a denser layer formation on WQ specimen. The precipitation formed on WQ specimens is the least among three kinds of specimens. Palladium is not found on the surfaces after exposure to SBF.

  17. Design for robustness of unique, multi-component engineering systems

    Science.gov (United States)

    Shelton, Kenneth A.

    2007-12-01

    The purpose of this research is to advance the science of conceptual designing for robustness in unique, multi-component engineering systems. Robustness is herein defined as the ability of an engineering system to operate within a desired performance range even if the actual configuration has differences from specifications within specified tolerances. These differences are caused by three sources, namely manufacturing errors, system degradation (operational wear and tear), and parts availability. Unique, multi-component engineering systems are defined as systems produced in unique or very small production numbers. They typically have design and manufacturing costs on the order of billions of dollars, and have multiple, competing performance objectives. Design time for these systems must be minimized due to competition, high manpower costs, long manufacturing times, technology obsolescence, and limited available manpower expertise. Most importantly, design mistakes cannot be easily corrected after the systems are operational. For all these reasons, robustness of these systems is absolutely critical. This research examines the space satellite industry in particular. Although inherent robustness assurance is absolutely critical, it is difficult to achieve in practice. The current state of the art for robustness in the industry is to overdesign components and subsystems with redundancy and margin. The shortfall is that it is not known if the added margins were either necessary or sufficient given the risk management preferences of the designer or engineering system customer. To address this shortcoming, new assessment criteria to evaluate robustness in design concepts have been developed. The criteria are comprised of the "Value Distance", addressing manufacturing errors and system degradation, and "Component Distance", addressing parts availability. They are based on an evolutionary computation format that uses a string of alleles to describe the components in the

  18. Development of 3D Multicomponent Model for Cold Spray Process Using Nitrogen and Air

    Directory of Open Access Journals (Sweden)

    Muhammad Faizan Ur Rab

    2015-10-01

    Full Text Available Cold spray is a unique coating technology that allows for solid state deposition of particles under atmospheric pressure. In this paper, a three dimensional, Computational Fluid Dynamics (CFD multicomponent model is developed to estimate cold spray gas conditions involving both nitrogen and air. Calibration of the model followed by validation is accomplished by considering the thermal history of substrate exposed to cold spray supersonic jet. The developed holistic multicomponent model is effective in determining the state of gas and particles from injection point to the substrate surface with the advantage of optimizing very rapid cold spray deposition in nanoseconds. The validation of k-ε type CFD multicomponent model is done by using the temperature measured for a titanium substrate exposed to cold spray nitrogen at 800 °C and 3 MPa. Heat transfer and radiation are considered for the de Laval nozzle used in cold spray experiments. The calibrated multicomponent model has successfully estimated the state of propellant gas for the chosen high pressure and high temperature cold spray conditions. Moreover, the multicomponent model predictions are in good agreement with a previous holistic three dimensional cold spray model in which only nitrogen was used as the surrounding as well as the propellant gas.

  19. Ultrafine particles

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Weschler, Charles J.; Wierzbicka, Aneta

    2013-01-01

    Particle number (PN) concentrations (10-300 nm in size) were continuously measured over a period of ∼45 h in 56 residences of nonsmokers in Copenhagen, Denmark. The highest concentrations were measured when occupants were present and awake (geometric mean, GM: 22.3 × 103 cm-3), the lowest when...... the homes were vacant (GM: 6.1 × 103 cm-3) or the occupants were asleep (GM: 5.1 × 103 cm-3). Diary entries regarding occupancy and particle related activities were used to identify source events and apportion the daily integrated exposure among sources. Source events clearly resulted in increased PN...... concentrations and decreased average particle diameter. For a given event, elevated particle concentrations persisted for several hours after the emission of fresh particles ceased. The residential daily integrated PN exposure in the 56 homes ranged between 37 × 103 and 6.0 × 106 particles per cm3·h/day (GM: 3...

  20. Multi-level predictive maintenance for multi-component systems

    International Nuclear Information System (INIS)

    Nguyen, Kim-Anh; Do, Phuc; Grall, Antoine

    2015-01-01

    In this paper, a novel predictive maintenance policy with multi-level decision-making is proposed for multi-component system with complex structure. The main idea is to propose a decision-making process considered on two levels: system level and component one. The goal of the decision rules at the system level is to address if preventive maintenance actions are needed regarding the predictive reliability of the system. At component level the decision rules aim at identifying optimally a group of several components to be preventively maintained when preventive maintenance is trigged due to the system level decision. Selecting optimal components is based on a cost-based group improvement factor taking into account the predictive reliability of the components, the economic dependencies as well as the location of the components in the system. Moreover, a cost model is developed to find the optimal maintenance decision variables. A 14-component system is finally introduced to illustrate the use and the performance of the proposed predictive maintenance policy. Different sensitivity analysis are also investigated and discussed. Indeed, the proposed policy provides more flexibility in maintenance decision-making for complex structure systems, hence leading to significant profits in terms of maintenance cost when compared with existing policies. - Highlights: • A predictive maintenance policy for complex structure systems is proposed. • Multi-level decision process based on prognostic results is proposed. • A cost-based group importance measure is introduced for decision-making. • Both positive and negative dependencies between components are investigated. • A cost model and Monte Carlo simulation are developed for optimization process.

  1. Optical spectroscopy of the Ce-doped multicomponent garnets

    International Nuclear Information System (INIS)

    Canimoglu, A.; Karabulut, Y.; Ayvacikli, M.; Muresan, L.E.; Perhaita, I.; Barbu-Tudoran, L.; Garcia Guinea, J.; Karali, T.; Can, N.

    2016-01-01

    Here, we report our results referring to the preparation of Ce doped Y 2.22 MgGa 2 Al 2 SiO 12 , Y 1.93 MgAl 4 SiO 12 and Y 2.22 Gd 0.75 Ga 2 Al 3 O 12 using solid state reaction at high temperature. Several complementary methods (i.e. powder x-ray diffraction (XRPD), energy dispersive analysis of X-rays (EDX), scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR)) were studied to examine the effects of the synthesis procedure on the morphology and structure. XRD analyses revealed that all compounds include yttrium aluminate phase with garnet structure. Cathodoluminescence (CL), radioluminescence (RL) and photoluminescence (PL) measurements were carried out for clarification of relationship between host lattice defects and the spectral luminescence emissions. Luminescence emission of phosphors is peaked at 530 nm assigned to 5d-4f transitions of the dopant Ce 3+ ions with a broad emission band in 400–700 nm range. Under electron irradiation, the emission spectrum of Ce doped (YGd) 3 Ga 2 Al 3 O 12 is well defined and has a characteristic fairly narrow and sharp emission band peaking at 312 nm and 624 nm corresponding to transition of 6 P 7/2 → 8 S 7/2 and 6 G J → 6 P J (Gd 3+ ), respectively. We suggest some of phosphors might be excellent phototherapy phosphor materials under electron excitation. - Highlights: • Ce-doped Multicomponent Garnets were prepared solid state reaction method. • The shape and size of phosphor particles were examined. • The narrow band UV B emission due to Gd 3+ ions were observed.

  2. Cohesive, multicomponent, dense powder flow characterization by NIR.

    Science.gov (United States)

    Benedetti, C; Abatzoglou, N; Simard, J-S; McDermott, L; Léonard, G; Cartilier, L

    2007-05-24

    Non-aerated powder flows are frequently encountered in downstream pharmaceutical processes. Such flows occur at the entrance of powder compression units, and their characteristics are of great interest because any powder agglomeration or segregation can be detrimental to the quality of the final solid oral dosage form. This work was aimed at developing a process analytical technology (PAT) method, based on near-infrared spectroscopy (NIR) for the in-line powder flow characterization of pharmaceutical formulations. An Ibuprofen drug formulation was selected for study. A bench-scale hopper system was assembled to monitor powder flow behaviour. An in-line commercial NIR Axsun spectrometer and probe were chosen to collect in-line spectral data on dense, multicomponent, non-aerated powder flow prior to compression. Spectra were collected on flowing mannitol and pharmaceutical product blends. A specially designed, non-contact sampling interface allowed the collection of representative process powder flow spectra without affecting blend uniformity. A partial least squares chemometric model was developed for laboratory-prepared samples, to quantitatively determine the flowing powder's active pharmaceutical ingredient (API) level. Static sample spectra and flowing pure mannitol spectra proved to have a high degree of reproducibility. The model's standard error of calibration was 2.95% of the API level with a R2 of 0.991. Flowing blend powder spectra and API estimates showed variations consistent with those seen in model samples. The average values for flowing pharmaceutical blends were close to the API concentration, indicating that the proposed procedure was statistically acceptable. The model is considered very promising, and some improvements would lead to its final acceptance at production scale as a PAT tool.

  3. Modeling of Strain Effects in Multi-component Semiconductors

    Science.gov (United States)

    Arjmand, Mehrdad

    Strain affects the properties of crystalline material by changing the atomic symmetry. Controlling the strain in semiconductors helps to tune properties of material and design new material. For instance, strained semiconductor heterostructures have improved the efficiency of traditional solar cells remarkably. Another example of strain application is in electronic devices. Strained heterostructure nanowires provide a better control on electronic properties of gates used in transistors. Gate-all-around nanowires are promising candidates to power microprocessors in future. Strain is also used to make quantum dot structures from semiconductors. These quantum dots are used in quantum computing, diode lasers and sensors. Once the stored strain in a structure reaches a critical limit, it relaxes by triggering different phenomena in the structure. For instance, strain causes morphology change, plastic deformation, phase separation and intermixing, fracture, buckling, bulging and peeling. In order to use these strained structures for design purposes, it is critical to understand these different relaxation phenomena and be able to control them. Modeling provides a powerful framework to understand different relaxation mechanisms and provide guidance to control these strain induced phenomena. In this thesis, I have developed a continuum based model called "phase field" to study morphology change, plastic deformation and phase separation in multi-component semiconductors during growth and annealing processes. The advantage of phase field approach compared to some other modeling techniques is that it includes the effects of both thermodynamics and kinetics. Also, I have developed a continuum based elasto-plasticity model to study the effects of plastic relaxation in semiconductor nanowires. This model can particularly be useful for piezoelectric and surface stability analysis of nanowires.

  4. Nonideal mixing in multicomponent lipid/detergent systems

    Energy Technology Data Exchange (ETDEWEB)

    Tsamaloukas, Alekos; Szadkowska, Halina; Heerklotz, Heiko [Biozentrum of the University of Basel, Division of Biophysical Chemistry, Klingelbergstrasse 70, CH-4056 Basel (Switzerland)

    2006-07-19

    A detailed understanding of the mixing properties of membranes to which detergents are added is mandatory for improving the application and interpretation of detergent based protein or lipid extraction assays. For Triton X-100 (TX-100), a nonionic detergent frequently used in the process of solubilizing and purifying membrane proteins and lipids, we present here a detailed study of the mixing properties of binary and ternary lipid mixtures by means of high-sensitivity isothermal titration calorimetry (ITC). To this end the partitioning thermodynamics of TX-100 molecules from the aqueous phase to lipid bilayers composed of various mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), egg-sphingomyelin (SM), and cholesterol (cho) are characterized. Composition-dependent partition coefficients K are analysed within the frame of a thermodynamic model developed to describe nonideal mixing in multicomponent lipid/detergent systems. The results imply that POPC, fluid SM, and TX-100 mix almost ideally (nonideality parameters {rho}{sub {alpha}}{sub /{beta}}

  5. Multicomponent analytical methodology to control phthalates, synthetic musks, fragrance allergens and preservatives in perfumes.

    Science.gov (United States)

    Sanchez-Prado, Lucia; Llompart, Maria; Lamas, J Pablo; Garcia-Jares, Carmen; Lores, Marta

    2011-07-15

    A simple, fast, robust and reliable multicomponent analytical method applicable in control laboratories with a high throughput level has been developed to analyze commercial brands of perfumes. Contents of 52 cosmetic ingredients belonging to different chemical families can be determined in a single run. Instrumental linearity, precision of the method and recovery studies in real samples showed excellent results, so that quantification by external calibration can be effectively applied. Relevant limits of detection and quantification were obtained for all the targets considered, far below the legal requirements and amply adequate for its accurate analytical control. A survey of 70 commercial perfumes and colognes has been performed, in order to verify whether these products complied with the recent changes in European legislation: regarding the maxima allowed concentrations of the ingredients and/or ingredient labelling. All samples contained some of the target ingredients. Several samples do not comply with the regulations concerning the presence of phthalates. Musks data confirmed the trend about the replacement of nitromusks by polycyclic musks; as well as the noticeable introduction of macrocyclic musks in the perfumes composition. The prohibited musk moskene has been detected in one sample in an appreciable concentration. The average number of fragrance allergens is twelve per sample; their presence must be indicated in the list of ingredients when its concentration exceeds the 0.001%, but values higher than 1% have been found in some samples. Preservatives data show that parabens, although ubiquitous in other cosmetic products, are not widely used in perfumery. In contrast, the presence of BHT is indeed widespread. The degree of compliance with the European Regulation on the labelling has been evaluated in a subset of samples, and only about the 38% of the perfumes were properly labelled for the allergens tested. Copyright © 2011 Elsevier B.V. All rights

  6. X-band microwave absorbing characteristics of multicomponent composites with magnetodielectric fillers

    Energy Technology Data Exchange (ETDEWEB)

    Afghahi, Seyyed Salman Seyyed [Department of Materials Science and Engineering, Imam Hossein University, Tehran (Iran, Islamic Republic of); Jafarian, Mojtaba, E-mail: m.jafarian@srbiau.ac.ir [Young Researchers and Elite Club, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Stergiou, Charalampos A. [Lab. of Inorganic Materials, Centre for Research and Technology Hellas, 57001 Thermi (Greece)

    2016-12-01

    We have studied the microwave absorbing performance in the X-band (8–12.4 GHz) of epoxy composites filled with magnetic and dielectric oxides and multiwalled carbon nanotubes. To this end, pure cobalt-substituted Ba-hexaferrite and calcium titanate were synthesized with the hydrothermal method in the form of nanosized powder. Moreover, the produced powders were characterized in regard of their structural, morphological and static magnetic properties. For the electromagnetic investigation, composite samples were also prepared with various thicknesses up to 4 mm and two basic filler compositions; namely 30 wt% of BaCoFe{sub 11}O{sub 19} and 30 wt% of the mixture BaCoFe{sub 11}O{sub 19}/CaTiO{sub 3}/carbon nanotubes. The magnetic composites show strong but narrowband reflection losses up to 27.5 dB, whereas the magnetodielectric composites with maximum losses of 15.8 dB possess wider bandwidth of operation, due to improved impedance matching. Furthermore, the characteristic frequency of the maximum losses for these quarter-wavelength absorbers was verified to be in inverse proportion to the layer thickness. These findings are supported by reflectance measurements of the samples both in waveguide and free-space. - Highlights: • Single and multi-component composite absorbers with magnetodielectric fillers were synthesized. • The prepared absorbers are lightweight with 30 wt% filler content in epoxy matrix. • The microwave absorption characteristics of composites were measured by waveguide and free-space methods in the X-band. • Composites with a combination of magnetic and dielectric fillers exhibit wider reflection loss peaks. • Composite absorbers have a realistic potential as microwave absorbers in the X-band.

  7. Three-dimensional model for multi-component reactive transport with variable density groundwater flow

    Science.gov (United States)

    Mao, X.; Prommer, H.; Barry, D.A.; Langevin, C.D.; Panteleit, B.; Li, L.

    2006-01-01

    PHWAT is a new model that couples a geochemical reaction model (PHREEQC-2) with a density-dependent groundwater flow and solute transport model (SEAWAT) using the split-operator approach. PHWAT was developed to simulate multi-component reactive transport in variable density groundwater flow. Fluid density in PHWAT depends not on only the concentration of a single species as in SEAWAT, but also the concentrations of other dissolved chemicals that can be subject to reactive processes. Simulation results of PHWAT and PHREEQC-2 were compared in their predictions of effluent concentration from a column experiment. Both models produced identical results, showing that PHWAT has correctly coupled the sub-packages. PHWAT was then applied to the simulation of a tank experiment in which seawater intrusion was accompanied by cation exchange. The density dependence of the intrusion and the snow-plough effect in the breakthrough curves were reflected in the model simulations, which were in good agreement with the measured breakthrough data. Comparison simulations that, in turn, excluded density effects and reactions allowed us to quantify the marked effect of ignoring these processes. Next, we explored numerical issues involved in the practical application of PHWAT using the example of a dense plume flowing into a tank containing fresh water. It was shown that PHWAT could model physically unstable flow and that numerical instabilities were suppressed. Physical instability developed in the model in accordance with the increase of the modified Rayleigh number for density-dependent flow, in agreement with previous research. ?? 2004 Elsevier Ltd. All rights reserved.

  8. Outdoor fine and ultrafine particle measurements at six bus stops with smoking on two California arterial highways--results of a pilot study.

    Science.gov (United States)

    Ott, Wayne R; Acevedo-Bolton, Viviana; Cheng, Kai-Chung; Jiang, Ruo-Ting; Klepeis, Neil E; Hildemann, Lynn M

    2014-01-01

    As indoor smoking bans have become widely adopted, some U.S. communities are considering restricting smoking outdoors, creating a need for measurements of air pollution near smokers outdoors. Personal exposure experiments were conducted with four to five participants at six sidewalk bus stops located 1.5-3.3 m from the curb of two heavily traveled California arterial highways with 3300-5100 vehicles per hour. At each bus stop, a smoker in the group smoked a cigarette. Gravimetrically calibrated continuous monitors were used to measure fine particle concentrations (aerodynamic diameter bus stop, ultrafine particles (UFP), wind speed, temperature, relative humidity, and traffic counts were also measured. For 13 cigarette experiments, the mean PM2.5 personal exposure of the nonsmoker seated 0.5 m from the smoker during a 5-min cigarette ranged from 15 to 153 microg/m3. Of four persons seated on the bench, the smoker received the highest PM2.5 breathing-zone exposure of 192 microg/m3. There was a strong proximity effect: nonsmokers at distances 0.5, 1.0, and 1.5 m from the smoker received mean PM2.5 personal exposures of 59, 40, and 28 microg/m3, respectively, compared with a background level of 1.7 microg/m3. Like the PM2.5 concentrations, UFP concentrations measured 0.5 m from the smoker increased abruptly when a cigarette started and decreased when the cigarette ended, averaging 44,500 particles/cm3 compared with the background level of 7200 particles/cm3. During nonsmoking periods, the UFP background concentrations showed occasional peaks due to traffic, whereas PM2.5 background concentrations were extremely low. The results indicate that a single cigarette smoked outdoors at a bus stop can cause PM2.5 and UFP concentrations near the smoker that are 16-35 and 6.2 times, respectively, higher than the background concentrations due to cars and trucks on an adjacent arterial highway. Rules banning smoking indoors have been widely adopted in the United States and in

  9. The Huber’s Method-based Gas Concentration Reconstruction in Multicomponent Gas Mixtures from Multispectral Laser Measurements under Noise Overshoot Conditions

    Directory of Open Access Journals (Sweden)

    V. A. Gorodnichev

    2016-01-01

    Full Text Available Laser gas analysers are the most promising for the rapid quantitative analysis of gaseous air pollution. A laser gas analysis problem is that there are instable results in reconstruction of gas mixture components concentration under real noise in the recorded laser signal. This necessitates using the special processing algorithms. When reconstructing the quantitative composition of multi-component gas mixtures from the multispectral laser measurements are efficiently used methods such as Tikhonov regularization, quasi-solution search, and finding of Bayesian estimators. These methods enable using the single measurement results to determine the quantitative composition of gas mixtures under measurement noise. In remote sensing the stationary gas formations or in laboratory analysis of the previously selected (when the gas mixture is stationary air samples the reconstruction procedures under measurement noise of gas concentrations in multicomponent mixtures can be much simpler. The paper considers a problem of multispectral laser analysis of stationary gas mixtures for which it is possible to conduct a series of measurements. With noise overshoots in the recorded laser signal (and, consequently, overshoots of gas concentrations determined by a single measurement must be used stable (robust estimation techniques for substantial reducing an impact of the overshoots on the estimate of required parameters. The paper proposes the Huber method to determine gas concentrations in multicomponent mixtures under signal overshoot. To estimate the value of Huber parameter and the efficiency of Huber's method to find the stable estimates of gas concentrations in multicomponent stationary mixtures from the laser measurements the mathematical modelling was conducted. Science & Education of the Bauman MSTU 108 The mathematical modelling results show that despite the considerable difference among the errors of the mixture gas components themselves a character of

  10. Impact of multicomponent ionic transport on pH fronts propagation in saturated porous media

    DEFF Research Database (Denmark)

    Muniruzzaman, Muhammad; Rolle, Massimo

    2016-01-01

    Multicomponent ionic interactions have been increasingly recognized as important factors for the displacement of charged species in porous media under both diffusion- [1,2] and advection-dominated flow regimes [3,4]. In this study we investigate the propagation of pH fronts during multicomponent...... simulations were performed to interpret the laboratory experiments. The simulations were based on a multicomponent ionic formulation accurately capturing the Coulombic interactions between the transported ions in the flow-through system. The results of purely forward simulations show a very good agreement...... ionic transport in saturated porous media under flow-through conditions. By performing laboratory bench-scale experiments combined with numerical modeling we show the important influence of Coulombic effects on proton transport in the presence of ionic admixtures. The experiments were performed...

  11. General statistical-thermodynamical treatment of one-dimensional multicomponent molecular hetero-assembly in solution

    International Nuclear Information System (INIS)

    Buchelnikov, Anatoly S.; Evstigneev, Vladyslav P.; Evstigneev, Maxim P.

    2013-01-01

    Highlights: • Multicomponent non-covalent molecular hetero-association has been modeled. • The equations obtained have an exclusive link to experimental observable. • The matrix form of key equations distinguishes the present model from other known. - Abstract: A general treatment has been developed for the multicomponent one-dimensional non-covalent molecular hetero-assembly in solution using transfer matrix and sequence generating function approaches. The main result is set of equations, which allows one to obtain any thermodynamical quantities of the multicomponent system and, in particular, experimental observable enabling one to get all equilibrium parameters of molecular interaction. The matrix form of presentation of the key equations allows their direct incorporation into matrix-oriented mathematical software, which leads to a two orders of magnitude increase in speed of calculation of as compared to other known approaches

  12. Current state in adsorption from multicomponent solutions of nonelectrolytes on solids

    International Nuclear Information System (INIS)

    Borowko, M.; Jaroniec, M.

    1983-01-01

    This paper surveys the research carried out on the adsorption from multicomponent liquid mixtures of nonelectrolytes on solids with emphasis on the work performed by the authors. The consistent theoretical treatment of adsorption from concentrated and dilute multicomponent solutions and its application to the liquid adsorption chromatography with the mixed mobile phase are presented. This treatment involved nonideality of the bulk and surface phases, energetic heterogeneity of the adsorbent surface and it may be extended to multilayer adsorption from solutions. The multicomponent liquid/solid adsorption systems, studied experimentally, are reviewed. Many of them have been examined by means of the equations derived for liquid adsorption on heterogeneous surfaces. These studies are summarized in this paper. Moreover, the model studies illustrating the influence of solution nonideality and adsorbent heterogeneity on the excess adsorption isotherms and the distribution coefficient are discussed. (orig.)

  13. Microstructural influence on low-temperature superplasticity of ultrafine-grained Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Young Gun [Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Kim, Woo Gyeom [Department of Metallurgy and Materials Science, Hanyang University, Ansan, Gyeonggi-Do 425-791 (Korea, Republic of); Lee, Chong Soo [Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)]. E-mail: cslee@postech.ac.kr; Shin, Dong Hyuk [Department of Metallurgy and Materials Science, Hanyang University, Ansan, Gyeonggi-Do 425-791 (Korea, Republic of)

    2005-11-25

    Microstructural influence on low-temperature superplastic behavior of ultrafine-grained Ti-6Al-4V alloy fabricated by equal channel angular pressing (ECAP) was investigated. The deformed structures were analyzed with the increment of strain by transmission electron microscopy. Also, a series of tensile tests were carried out on ultrafine-grained (UFG) samples to measure elongation at temperature of 973 K and at strain rates of 10{sup -4} to 10{sup -2} s{sup -1}. The results indicated that elongation was significantly increased with increasing ECAP straining from 4 to 8 revealing more high-angle grain boundaries. Deformation mechanisms for UFG structure were analyzed in the context of inelastic deformation theory, which consisted of dislocation glide and grain boundary sliding.

  14. Influence of fraction of high angle boundaries on the mechanical behavior of an ultrafine grained Al-Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kapoor, R.; Kumar, N. [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Mishra, R.S., E-mail: rsmishra@mst.edu [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Huskamp, C.S.; Sankaran, K.K. [Boeing Research and Technology, Boeing Company, St. Louis, MO 63166 (United States)

    2010-07-25

    The mechanical behavior of ultrafine grained AA5052 processed through different techniques-rolled, annealed, friction stir processed (FSP) and equal channel angular pressed (ECAP)-were compared and correlated with microstructure. The microstructure was characterized using electron back scattered diffraction to obtain the boundary spacing, the fraction of high angle boundaries and to estimate the dislocation density from local misorientations. Both FSP and ECAP conditions had ultrafine boundary spacing, but the fraction of high angle boundaries was larger for the FSP condition. Tensile deformation carried out at 297 K and 10{sup -3} s{sup -1} showed a lower work-hardening rate and recovery rate for FSP as compared to the ECAP condition. It was inferred that low angle boundaries are more effective sinks for dislocations. When comparing differently processed materials, the strength, ductility and work-hardening behavior correlate better with the fraction of high angle boundaries than the boundary spacing.

  15. Effect of Temperature and Chloride Ion Concentration on Corrosion of Passive Films on Nano/Ultrafine Grained Stainless Steels

    Science.gov (United States)

    Jinlong, Lv; Hongyun, Luo

    2014-12-01

    The effects of solution temperature, concentration of chloride ions, and grain refinement on the corrosion resistance of the passive film formed on 304 stainless steels in borate buffer solution were investigated by electrochemical impedance spectroscopy and Mott-Schottky measurements. The results showed that the passive films formed on the surface of 304 stainless steels possessed n- and p-type semiconductor characteristics. With the increase of solution temperature, the corrosion resistance of the passive film of coarse and nano/ultrafine grained stainless steels decreased. However, the corrosion resistance of the passive film in nano/ultrafine grained stainless steel was higher than that in the coarse grained one. Moreover, in cyclic potentiodynamic polarization tests, chloride ions changed semiconductor characteristics of the passive film formed on the surface of stainless steel.

  16. Facile Fabrication of Ultrafine Hollow Silica and Magnetic Hollow Silica Nanoparticles by a Dual-Templating Approach

    Directory of Open Access Journals (Sweden)

    Xiao Xiangheng

    2009-01-01

    Full Text Available Abstract The development of synthetic process for hollow silica materials is an issue of considerable topical interest. While a number of chemical routes are available and are extensively used, the diameter of hollow silica often large than 50 nm. Here, we report on a facial route to synthesis ultrafine hollow silica nanoparticles (the diameter of ca. 24 nm with high surface area by using cetyltrimethylammmonium bromide (CTAB and sodium bis(2-ethylhexyl sulfosuccinate (AOT as co-templates and subsequent annealing treatment. When the hollow magnetite nanoparticles were introduced into the reaction, the ultrafine magnetic hollow silica nanoparticles with the diameter of ca. 32 nm were obtained correspondingly. Transmission electron microscopy studies confirm that the nanoparticles are composed of amorphous silica and that the majority of them are hollow.

  17. Facile Fabrication of Ultrafine Hollow Silica and Magnetic Hollow Silica Nanoparticles by a Dual-Templating Approach.

    Science.gov (United States)

    Wu, Wei; Xiao, Xiangheng; Zhang, Shaofeng; Fan, Lixia; Peng, Tangchao; Ren, Feng; Jiang, Changzhong

    2009-10-10

    The development of synthetic process for hollow silica materials is an issue of considerable topical interest. While a number of chemical routes are available and are extensively used, the diameter of hollow silica often large than 50 nm. Here, we report on a facial route to synthesis ultrafine hollow silica nanoparticles (the diameter of ca. 24 nm) with high surface area by using cetyltrimethylammmonium bromide (CTAB) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as co-templates and subsequent annealing treatment. When the hollow magnetite nanoparticles were introduced into the reaction, the ultrafine magnetic hollow silica nanoparticles with the diameter of ca. 32 nm were obtained correspondingly. Transmission electron microscopy studies confirm that the nanoparticles are composed of amorphous silica and that the majority of them are hollow.

  18. High-Temperature Compensation Effect of Dynamic Viscosity in Multicomponent Hydrocarbon Media

    Science.gov (United States)

    Dolomatov, M. Yu.; Nizamova, G. I.; Zhuravleva, N. A.

    2017-07-01

    Linear dependences connecting the preexponent to the activation energy of viscous flow in the Frenkel-Eyring equation have been obtained for multicomponent hydrocarbon media (high-boiling distillate fractions). For these media, the kinetic compensation effect has been established whose distinctive feature is its action in the temperature range including the temperature of thermal destruction (400-450°C) of the indicated media. The obtained results have been confirmed by statistical-processing data and make it possible to predict the dynamic viscosity of multicomponent hydrocarbon systems, such as tars and other high-boiling oil distillates.

  19. A self-consistent model for thermodynamics of multicomponent solid solutions

    International Nuclear Information System (INIS)

    Svoboda, J.; Fischer, F.D.

    2016-01-01

    The self-consistent concept recently published in this journal (108, 27–30, 2015) is extended from a binary to a multicomponent system. This is possible by exploiting the trapping concept as basis for including the interaction of atoms in terms of pairs (e.g. A–A, B–B, C–C…) and couples (e.g. A–B, B–C, …) in a multicomponent system with A as solvent and B, C, … as dilute solutes. The model results in a formulation of Gibbs-energy, which can be minimized. Examples show that the couple and pair formation may influence the equilibrium Gibbs energy markedly.

  20. Does physical exercise in addition to a multicomponent smoking cessation program increase abstinence rate and suppress weight gain? An intervention study.

    Science.gov (United States)

    Jonsdottir, D; Jonsdottir, H

    2001-01-01

    Does physical exercise in addition to a multicomponent smoking cessation program increase abstinence rate and suppress weight gain? An intervention study Tobacco use is considered the single most preventable cause of premature morbidity and mortality. Smoking cessation programs aim at two interrelated purposes, to help people to give up smoking and to prevent relapse. A multicomponent intervention consisting of nicotine replacement therapy, health education, behaviour modification therapy and counselling is widely recommended in the health care literature. Smoking cessation studies from a nursing perspective are few. The purpose of this quasi-experimental study was to compare outcomes of two nurse-managed 1-year group smoking cessation interventions. Intervention 1 (n=34) was provided at a health care centre and consisted of nicotine replacement therapy, health education, behavioural modification and individual and group counselling. In intervention 2 (n=33), provided in a health club, physical exercise was added to the intervention provided in 1. Participants were self-referred with equal numbers in both interventions. A nonsignificant difference in lapse free abstinence time (LFAT) at 1 year was demonstrated between intervention 1 (20.6%, n=7) and intervention 2 (39.4%, n=13) (p=0.16, odds ratio=2.5). The difference in weight gain between intervention groups was also nonsignificant. Within intervention comparison between abstinent participants and smokers showed that abstinent participants had gained significantly more weight than smokers in intervention 2 (p=0.001), but in intervention 1 the difference was nonsignificant (p=0.2). The small sample size in the study detracts from the significance of the findings. However, a trend is observed showing that physical exercise increases the abstinence rate of participants. The conclusion is drawn that a multicomponent smoking cessation program that includes physical exercise might be an effective intervention, but

  1. Identification and verification of ultrafine particle affinity zones in urban neighbourhoods: sample design and data pre-processing.

    LENUS (Irish Health Repository)

    Harris, Paul

    2009-01-01

    A methodology is presented and validated through which long-term fixed site air quality measurements are used to characterise and remove temporal signals in sample-based measurements which have good spatial coverage but poor temporal resolution. The work has been carried out specifically to provide a spatial dataset of atmospheric ultrafine particle (UFP < 100 nm) data for ongoing epidemiologic cohort analysis but the method is readily transferable to wider epidemiologic investigations and research into the health effects of other pollutant species.

  2. Impact of two particle measurement techniques on the determination of N95 class respirator filtration performance against ultrafine particles

    International Nuclear Information System (INIS)

    Mostofi, Reza; Noël, Alexandra; Haghighat, Fariborz; Bahloul, Ali; Lara, Jaime; Cloutier, Yves

    2012-01-01

    Highlights: ► Performance evaluation of respirator using two different measurement techniques. ► Impaction and electrical mobility were used to characterize ultrafine particle. ► The experiment was done using ultrafine-sized poly-dispersed aerosols. ► Both techniques show that MPPS would occur at a similar size range. - Abstract: The purpose of this experimental study was to compare two different particle measurement devices; an Electrical Low Pressure Impactor (ELPI) and a Scanning Mobility Particle Sizer (SMPS), to measure the number concentration and the size distribution of NaCl salt aerosols to determine the collection efficiency of filtering respirators against poly disperse aerosols. Tests were performed on NIOSH approved N95 filtering face-piece respirators (FFR), sealed on a manikin head. Ultrafine particles found in the aerosols were also collected and observed by transmission electron microscopy (TEM). According to the results, there is a systematic difference for the particle size distribution measured by the SMPS and the ELPI. It is largely attributed to the difference in the measurement techniques. However, in spite of these discrepancies, reasonably similar trends were found for the number concentration with both measuring instruments. The particle penetration, calculated based on mobility and aerodynamic diameters, never exceeded 5% for any size range measured at constant flow rate of 85 L/min. Also, the most penetrating particle size (MPPS), with the lowest filtration efficiency, would occur at a similar ultrafine size range <100 nm. With the ELPI, the MPPS was at 70 nm aerodynamic diameter, whereas it occurred at 40 nm mobility diameter with the SMPS.

  3. Plasticity mechanisms in ultrafine grained freestanding aluminum thin films revealed by in-situ transmission electron microscopy nanomechanical testing

    International Nuclear Information System (INIS)

    Idrissi, Hosni; Kobler, Aaron; Amin-Ahmadi, Behnam; Schryvers, Dominique; Coulombier, Michael; Pardoen, Thomas; Galceran, Montserrat; Godet, Stéphane; Raskin, Jean-Pierre; Kübel, Christian

    2014-01-01

    In-situ bright field transmission electron microscopy (TEM) nanomechanical tensile testing and in-situ automated crystallographic orientation mapping in TEM were combined to unravel the elementary mechanisms controlling the plasticity of ultrafine grained Aluminum freestanding thin films. The characterizations demonstrate that deformation proceeds with a transition from grain rotation to intragranular dislocation glide and starvation plasticity mechanism at about 1% deformation. The grain rotation is not affected by the character of the grain boundaries. No grain growth or twinning is detected

  4. Strain localization and fatigue crack initiation in ultrafine-grained copper in high- and giga-cycle region

    Czech Academy of Sciences Publication Activity Database

    Kunz, Ludvík; Lukáš, Petr; Navrátilová, L.

    2014-01-01

    Roč. 58, JAN (2014), s. 202-208 ISSN 0142-1123 R&D Projects: GA ČR GAP108/10/2001; GA MŠk(CZ) ED1.1.00/02.0068 Institutional support: RVO:68081723 Keywords : Fatigue crack initiation * Strain localization * Stability of ultrafine-grained structure * UFG Cu Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.275, year: 2014

  5. Microstructure Mechanisms Governing the Creep Life of Ultrafine-grained Cu-0.2wt.%Zr Alloy

    Czech Academy of Sciences Publication Activity Database

    Král, Petr; Svoboda, Milan; Dvořák, Jiří; Kvapilová, Marie; Sklenička, Václav

    2012-01-01

    Roč. 122, č. 3 (2012), s. 457-460 ISSN 0587-4246. [International Symposium on Physics of Materials /12./. Praha, 04.09.2011-08.09.2011] R&D Projects: GA ČR(CZ) GAP108/11/2260 Institutional research plan: CEZ:AV0Z20410507 Keywords : equal-channel angular pressing * creep behaviour * ultrafine-grained materials Subject RIV: JJ - Other Materials Impact factor: 0.531, year: 2012

  6. Electrochemical behavior of copper metal core/oxide shell ultra-fine particles on mercury electrodes in aqueous dispersions

    Czech Academy of Sciences Publication Activity Database

    Korshunov, A.; Heyrovský, Michael

    2009-01-01

    Roč. 629, 1-2 (2009), s. 23-29 ISSN 0022-0728 R&D Projects: GA ČR GA203/07/1195; GA AV ČR IAA400400806 Institutional research plan: CEZ:AV0Z40400503 Keywords : ultrafine copper powders * surface oxide layers * aqueous dispersions * voltammetry * Hg electrodes Subject RIV: CG - Electrochemistry Impact factor: 2.580, year: 2007

  7. Segregation of solute elements at grain boundaries in an ultrafine grained Al-Zn-Mg-Cu alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sha, Gang, E-mail: g.sha@usyd.edu.au [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); ARC Centre of Excellence for Design in Light Metals, The University of Sydney, NSW 2006 (Australia); Yao, Lan [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Liao, Xiaozhou [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia); Ringer, Simon P. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); ARC Centre of Excellence for Design in Light Metals, The University of Sydney, NSW 2006 (Australia); Chao Duan, Zhi [Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Langdon, Terence G. [Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Materials Research Group, School of Engineering Sciences, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2011-05-15

    The solute segregation at grain boundaries (GBs) of an ultrafine grained (UFG) Al-Zn-Mg-Cu alloy processed by equal-channel angular pressing (ECAP) at 200 {sup o}C was characterised using three-dimensional atom probe. Mg and Cu segregate strongly to the grain boundaries. In contrast, Zn does not always show clear segregation and may even show depletion near the grain boundaries. Trace element Si selectively segregates at some GBs. An increase in the number of ECAP passes leads to a decrease in the grain size but an increase in solute segregation at the boundaries. The significant segregation of alloying elements at the boundaries of ultrafine-grained alloys implies that less solutes will be available in the matrix for precipitation with a decrease in the average grain size. -- Research Highlights: {yields} Atom probe tomography has been employed successfully to reveal unique segregation of solutes at ultrafine grained material. {yields} Mg and Cu elements segregated strongly at the grain boundary of an ultrafine grained Al-Zn-Mg-Cu alloy processed by 4-pass and 8-pass ECAP at 200 {sup o}C. Zn frequently depleted at GBs with a Zn depletion region of 7-15 nm in width on one or both sides of the GBs. Only a small fraction (3/13) of GBs were observed with a low level of Zn segregation where the combined Mg and Cu excess is over 3.1 atom/nm{sup 2}. Si appeared selectively segregated at some of the GBs. {yields} The increase in number of ECAP passes from 4 to 8 correlated with the increase in mean level segregation of Mg and Cu for both solute excess and peak concentration. {yields} The change of plane normal of a grain boundary within 30{sup o} only leads to a slight change in the solute segregation level.

  8. Segregation of solute elements at grain boundaries in an ultrafine grained Al-Zn-Mg-Cu alloy

    International Nuclear Information System (INIS)

    Sha, Gang; Yao, Lan; Liao, Xiaozhou; Ringer, Simon P.; Chao Duan, Zhi; Langdon, Terence G.

    2011-01-01

    The solute segregation at grain boundaries (GBs) of an ultrafine grained (UFG) Al-Zn-Mg-Cu alloy processed by equal-channel angular pressing (ECAP) at 200 o C was characterised using three-dimensional atom probe. Mg and Cu segregate strongly to the grain boundaries. In contrast, Zn does not always show clear segregation and may even show depletion near the grain boundaries. Trace element Si selectively segregates at some GBs. An increase in the number of ECAP passes leads to a decrease in the grain size but an increase in solute segregation at the boundaries. The significant segregation of alloying elements at the boundaries of ultrafine-grained alloys implies that less solutes will be available in the matrix for precipitation with a decrease in the average grain size. -- Research Highlights: → Atom probe tomography has been employed successfully to reveal unique segregation of solutes at ultrafine grained material. → Mg and Cu elements segregated strongly at the grain boundary of an ultrafine grained Al-Zn-Mg-Cu alloy processed by 4-pass and 8-pass ECAP at 200 o C. Zn frequently depleted at GBs with a Zn depletion region of 7-15 nm in width on one or both sides of the GBs. Only a small fraction (3/13) of GBs were observed with a low level of Zn segregation where the combined Mg and Cu excess is over 3.1 atom/nm 2 . Si appeared selectively segregated at some of the GBs. → The increase in number of ECAP passes from 4 to 8 correlated with the increase in mean level segregation of Mg and Cu for both solute excess and peak concentration. → The change of plane normal of a grain boundary within 30 o only leads to a slight change in the solute segregation level.

  9. Removal of fluoride from drinking water using modified ultrafine tea powder processed using a ball-mill

    International Nuclear Information System (INIS)

    Cai, Huimei; Xu, Lingyun; Chen, Guijie; Peng, Chuanyi; Ke, Fei; Liu, Zhengquan; Li, Daxiang; Zhang, Zhengzhu; Wan, Xiaochun

    2016-01-01

    Highlights: • Ultrafine tea powder (UTP) was prepared by ball-milling. • A novel and high efficient biosorbent from ultrafine tea powder (UTP) for the removal of fluoride from drinking water was prepared. • Loaded ultrafine tea powder adsorbed more fluoride adsorption than loaded tea waste. • UTP-Zr performed well over a considerably wide pH range, from 3.0 to 10.0. • UTP-Zr retains Zr metal ion during defluoridation, limiting secondary pollution. - Abstract: A low-cost and highly efficient biosorbent was prepared by loading zirconium(IV) onto ball-milled, ultrafine tea powder (UTP-Zr) for removal of fluoride from drinking water. To evaluate the fluoride adsorption capacity of UTP-Zr over a wide range of conditions, the biosorbent dosage, contact time, initial pH, initial fluoride concentration and presence of other ions were varied. UTP-Zr performed well over the considerably wide pH range of 3–10. The residual concentration of Zr in the treated water was below the limit of detection (0.01 mg/L). Fluoride adsorption by the UTP-Zr biosorbent followed the Langmuir model, with a maximum adsorption capacity of 12.43 mgF/g at room temperature. The fluoride adsorption kinetics fit the pseudo-second-order kinetic model. The synthesized biosorbent was characterized by BET, SEM, EDS, XRD and XPS to reveal how UTP-Zr interacts with fluoride. Results from this study demonstrated that UTP-based biosorbents will be useful and safe for the removal of fluoride from drinking water.

  10. Ultrafine particles are not major carriers of carcinogenic PAHs and their genotoxicity in size-segregated aerosols

    Czech Academy of Sciences Publication Activity Database

    Topinka, Jan; Milcová, Alena; Schmuczerová, Jana; Kroužek, J.; Hovorka, J.

    2013-01-01

    Roč. 754, 1-2 (2013), s. 1-6 ISSN 1383-5718 R&D Projects: GA ČR(CZ) GAP503/11/0142; GA ČR(CZ) GBP503/12/G147 Grant - others:MZP(CZ) SP/1A3/149/08 Institutional support: RVO:68378041 Keywords : Air pollution * Ultrafine particles * Carcinogenic PAHs Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 2.481, year: 2013

  11. Facile Fabrication of Ultrafine Hollow Silica and Magnetic Hollow Silica Nanoparticles by a Dual-Templating Approach

    OpenAIRE

    Wu, Wei; Xiao, Xiangheng; Zhang, Shaofeng; Fan, Lixia; Peng, Tangchao; Ren, Feng; Jiang, Changzhong

    2009-01-01

    Abstract The development of synthetic process for hollow silica materials is an issue of considerable topical interest. While a number of chemical routes are available and are extensively used, the diameter of hollow silica often large than 50 nm. Here, we report on a facial route to synthesis ultrafine hollow silica nanoparticles (the diameter of ca. 24 nm) with high surface area by using cetyltrimethylammmonium bromide (CTAB) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as co-templates...

  12. N-2 laser-induced formation of copolymeric ultrafine particles in a gaseous tetraethenylgermane-carbon disulfide mixture

    Czech Academy of Sciences Publication Activity Database

    Morita, H.; Semba, K.; Bastl, Zdeněk; Šubrt, Jan; Pola, Josef

    2005-01-01

    Roč. 171, č. 1 (2005), s. 21-26 R&D Projects: GA MŠk(CZ) ME 612 Grant - others:Grant-in-Aid for Scientific Research on Priority Area "Innovative utilization of strong magnetic fields", MEXT (JP) 15085203 Institutional research plan: CEZ:AV0Z40400503 Keywords : ultrafine particles * photo-polymerization * tetraethenylgermane * carbon disulphide Subject RIV: CF - Physical ; Theoretical Chemistry

  13. Internal Combustion Engines as the Main Source of Ultrafine Particles in Residential Neighborhoods: Field Measurements in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Štolcpartová, Jitka; Pechout, M.; Dittrich, L.; Mazač, M.; Fenkl, M.; Vrbová, Kristýna; Ondráček, Jakub; Vojtíšek-Lom, M.

    2015-01-01

    Roč. 6, č. 11 (2015), s. 1714-1735 ISSN 2073-4433 R&D Projects: GA ČR(CZ) GBP503/12/G147; GA ČR(CZ) GA13-01438S Institutional support: RVO:68378041 ; RVO:67985858 Keywords : ultrafine particles * nanoparticles * UFP Subject RIV: DN - Health Impact of the Environment Quality; DI - Air Pollution ; Quality (UCHP-M) Impact factor: 1.221, year: 2015

  14. Pulmonary Delivery of an Ultra-Fine Oxytocin Dry Powder Formulation: Potential for Treatment of Postpartum Haemorrhage in Developing Countries

    OpenAIRE

    Prankerd, Richard J.; Nguyen, Tri-Hung; Ibrahim, Jibriil P.; Bischof, Robert J.; Nassta, Gemma C.; Olerile, Livesey D.; Russell, Adrian S.; Meiser, Felix; Parkington, Helena C.; Coleman, Harold A.; Morton, David A. V.; McIntosh, Michelle P.

    2013-01-01

    Oxytocin is recommended by the World Health Organisation as the most effective uterotonic for the prevention and treatment of postpartum haemorrhage. The requirement for parenteral administration by trained healthcare providers and the need for the drug solution to be maintained under cold-chain storage limit the use of oxytocin in the developing world. In this study, a spray-dried ultrafine formulation of oxytocin was developed with an optimal particle size diameter (1-5 µm) to facilitate ae...

  15. EFFICACY OF MODIFIED MULTICOMPONENT SYSTEM “1C: ENTERPRISE” IMPLEMENTATION

    Directory of Open Access Journals (Sweden)

    A. A. Modestov

    2016-01-01

    Full Text Available Background: Automated accounting and controlling system “1C: Enterprise” is widely used in Russia for optimizing the system of controlling materials and technical resources. Medical organizations modify them in line with their primary activity objectives. For many years, the Scientific Center of Children’s Health has been successfully using a 1C-based medical information system including electronic patient records. An innovative product — an additional block for accounting equipment and supplies (E&S — was developed in 2014.Objective: Our aim was to conduct a sociological analysis of results of the first stage of modified multicomponent system “1C: Enterprise” implementation.Methods: The cross-sectional full-design study was conducted from October 2014 to June 2015. We used the analytical method, the opinion poll method and the expert method. We developed a special questionnaire for the purposes of the poll. We assessed opinions of clinic employees, departments and services indirectly or directly working with the system.Results: The study results demonstrate that multifunctional and adapted towards peculiarities of activities of the Scientific Center of Children’s Health system “1C: Enterprise” provides more efficient control over the use of drugs, expendables and other E&S in patient terms. It also allows simplifying and automatizing operation of the E&S accounting system by the employees and generating financial statements for a given period in terms of patient/department/clinic. At the same time, the poll revealed problematic technical, informational and motivational aspects. This is confirmed by the degree of involvement/personal interest of employees in the end result, as well as by the priorities of motivation for quality work.Conclusion: Analysis of attitude of accountable persons to the modification of accounting policy of the Scientific Center of Children’s Health served as the basis for developing measures of

  16. Crystallisation mechanism of a multicomponent lithium alumino-silicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Wurth, R. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany); Pascual, M.J., E-mail: mpascual@icv.csic.es [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Mather, G.C.; Pablos-Martin, A.; Munoz, F.; Duran, A. [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Cuello, G.J. [Institut Laue-Langevin, Boite Postale 156, 38042 Grenoble Cedex 9 (France); Ruessel, C. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany)

    2012-06-15

    A base glass of composition 3.5 Li{sub 2}O Bullet-Operator 0.15 Na{sub 2}O Bullet-Operator 0.2 K{sub 2}O Bullet-Operator 1.15 MgO Bullet-Operator 0.8 BaO Bullet-Operator 1.5 ZnO Bullet-Operator 20 Al{sub 2}O{sub 3} Bullet-Operator 67.2 SiO{sub 2} Bullet-Operator 2.6 TiO{sub 2} Bullet-Operator 1.7 ZrO{sub 2} Bullet-Operator 1.2 As{sub 2}O{sub 3} (in wt.%), melted and provided by SCHOTT AG (Mainz), was used to study the crystallisation mechanism of lithium alumino-silicate glass employing X-ray diffraction combined with neutron diffraction and non-isothermal differential scanning calorimetry (DSC). A high-quartz solid solution of LiAlSi{sub 2}O{sub 6} with nanoscaled crystals forms at 750 Degree-Sign C. Quantitative Rietveld refinement of samples annealed at 750 Degree-Sign C for 8 h determined a crystallised fraction of around 59 wt.%. The room temperature crystallised phase adopts an ordered, {beta}-eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. The Avrami parameter (n {approx} 4), calculated from DSC data using different theoretical approaches, indicates that bulk crystallisation occurs and that the number of nuclei increases during annealing. The activation energy of the crystallisation is 531 {+-} 20 kJ mol{sup -1}. - Highlights: Black-Right-Pointing-Pointer Nanoscaled high-quartz crystals from a multicomponent lithium alumino-silicate glass. Black-Right-Pointing-Pointer Combined X-ray and neutron diffraction structural refinement. Black-Right-Pointing-Pointer {beta}-Eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. Black-Right-Pointing-Pointer 3-Dimensional bulk crystallisation mechanism with an increasing number of nuclei. Black-Right-Pointing-Pointer Usage and validation of an alternative approach to calculate the Avrami parameter.

  17. Comparison of Three Real-Time Measurement Methods for Airborne Ultrafine Particles in the Silicon Alloy Industry.

    Science.gov (United States)

    Kero, Ida Teresia; Jørgensen, Rikke Bramming

    2016-09-01

    The aim of this study was to compare the applicability and the correlation between three commercially available instruments capable of detection, quantification, and characterization of ultrafine airborne particulate matter in the industrial setting of a tapping area in a silicon alloy production plant. The number concentration of ultrafine particles was evaluated using an Electric Low Pressure Impactor (ELPI(TM)), a Fast Mobility Particle Sizer (FMPS(TM)), and a Condensation Particle Counter (CPC). The results are discussed in terms of particle size distribution and temporal variations linked to process operations. The instruments show excellent temporal covariation and the correlation between the FMPS and ELPI is good. The advantage of the FMPS is the excellent time- and size resolution of the results. The main advantage of the ELPI is the possibility to collect size-fractionated samples of the dust for subsequent analysis by, for example, electron microscopy. The CPC does not provide information about the particle size distribution and its correlation to the other two instruments is somewhat poor. Nonetheless, the CPC gives basic, real-time information about the ultrafine particle concentration and can therefore be used for source identification.

  18. The effect of anodic oxide coating on the fatigue behaviour of AA6082 with an ultrafine-grained microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, L.; Haendel, M.; Halle, T.; Nickel, D.; Alisch, G.; Lampke, T. [Technische Universitaet Chemnitz, Institut fuer Werkstoffwissenschaft und Werkstofftechnik, Chemnitz (Germany); Hockauf, K.

    2011-07-15

    In this work, the high-cycle fatigue behaviour of the precipitation hardening aluminium wrought alloy AA6082 was investigated for a conventionally-grained and an ultrafine-grained substrate condition, with each a hard and a soft electrolytic anodic oxide (EAO) coating. The investigations were focused on the susceptibility of the coatings to anodising- and fatigue-induced cracking of the coatings and its impact on the fatigue life. For both substrate materials, the fatigue strength of the coated specimens was significantly reduced compared to the uncoated materials. Considering the resistance to crack initiation in the coating, the soft-anodised coatings were found to be superior compared to the hard-anodised ones. Moreover, the coatings on the ultrafine-grained substrate showed an enhanced resistance to anodising-induced as well as fatigue-induced cracking. However, it is supposed that the lower resistance to crack transition from the coating into the substrate is one of the most important factors which strongly limits the fatigue life of the EAO-coated specimens. This might be the reason why the fatigue strength of the ultrafine-grained substrates is relatively low, despite their higher resistance to crack initiation. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Nuclear microprobe investigation of the penetration of ultrafine zinc oxide into human skin affected by atopic dermatitis

    Energy Technology Data Exchange (ETDEWEB)

    Szikszai, Z., E-mail: szikszai@atomki.hu [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen (Hungary); Kertesz, Zs. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen (Hungary); Bodnar, E. [Department of Dermatology, University of Debrecen, Medical and Health Science Center, Debrecen (Hungary); Borbiro, I. [Abiol Ltd., Debrecen (Hungary); Angyal, A.; Csedreki, L.; Furu, E.; Szoboszlai, Z.; Kiss, A.Z. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Debrecen (Hungary); Hunyadi, J. [Department of Dermatology, University of Debrecen, Medical and Health Science Center, Debrecen (Hungary)

    2011-10-15

    Skin penetration is one of the potential routes for nanoparticles to gain access into the human body. Ultrafine metal oxides, such as titanium dioxide and zinc oxide are widely used in cosmetic and health products like sunscreens. These oxides are potent UV filters and the particle size smaller than 200 nm makes the product more transparent compared to formulations containing coarser particles. The present study continues the work carried out in the frame of the NANODERM: 'Quality of skin as a barrier to ultrafine particles' European project and complements our previous investigations on human skin with compromised barrier function. Atopic dermatitis (a type of eczema) is an inflammatory, chronically relapsing, non-contagious skin disease. It is very common in children but may occur at any age. The exact cause of atopic dermatitis is unknown, but is likely due to a combination of impaired barrier function together with a malfunction in the body's immune system. In this study, skin samples were obtained from two patients suffering from atopic dermatitis. Our results indicate that the ultrafine zinc oxide particles, in a hydrophobic basis gel with an application time of 2 days or 2 weeks, have penetrated deeply into the stratum corneum in these patients. On the other hand, penetration into the stratum spinosum was not observed even in the case of the longer application time.

  20. Nuclear microprobe investigation of the penetration of ultrafine zinc oxide into human skin affected by atopic dermatitis

    Science.gov (United States)

    Szikszai, Z.; Kertész, Zs.; Bodnár, E.; Borbíró, I.; Angyal, A.; Csedreki, L.; Furu, E.; Szoboszlai, Z.; Kiss, Á. Z.; Hunyadi, J.

    2011-10-01

    Skin penetration is one of the potential routes for nanoparticles to gain access into the human body. Ultrafine metal oxides, such as titanium dioxide and zinc oxide are widely used in cosmetic and health products like sunscreens. These oxides are potent UV filters and the particle size smaller than 200 nm makes the product more transparent compared to formulations containing coarser particles. The present study continues the work carried out in the frame of the NANODERM: “Quality of skin as a barrier to ultrafine particles” European project and complements our previous investigations on human skin with compromised barrier function. Atopic dermatitis (a type of eczema) is an inflammatory, chronically relapsing, non-contagious skin disease. It is very common in children but may occur at any age. The exact cause of atopic dermatitis is unknown, but is likely due to a combination of impaired barrier function together with a malfunction in the body's immune system. In this study, skin samples were obtained from two patients suffering from atopic dermatitis. Our results indicate that the ultrafine zinc oxide particles, in a hydrophobic basis gel with an application time of 2 days or 2 weeks, have penetrated deeply into the stratum corneum in these patients. On the other hand, penetration into the stratum spinosum was not observed even in the case of the longer application time.

  1. Comparison of Three Real-Time Measurement Methods for Airborne Ultrafine Particles in the Silicon Alloy Industry

    Science.gov (United States)

    Kero, Ida Teresia; Jørgensen, Rikke Bramming

    2016-01-01

    The aim of this study was to compare the applicability and the correlation between three commercially available instruments capable of detection, quantification, and characterization of ultrafine airborne particulate matter in the industrial setting of a tapping area in a silicon alloy production plant. The number concentration of ultrafine particles was evaluated using an Electric Low Pressure Impactor (ELPITM), a Fast Mobility Particle Sizer (FMPSTM), and a Condensation Particle Counter (CPC). The results are discussed in terms of particle size distribution and temporal variations linked to process operations. The instruments show excellent temporal covariation and the correlation between the FMPS and ELPI is good. The advantage of the FMPS is the excellent time- and size resolution of the results. The main advantage of the ELPI is the possibility to collect size-fractionated samples of the dust for subsequent analysis by, for example, electron microscopy. The CPC does not provide information about the particle size distribution and its correlation to the other two instruments is somewhat poor. Nonetheless, the CPC gives basic, real-time information about the ultrafine particle concentration and can therefore be used for source identification. PMID:27598180

  2. Surface chemical treatment of ultrafine-grained Ti–6Al–7Nb alloy processed by severe plastic deformation

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, D.P., E-mail: dpedreira@ufscar.br [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, São Carlos 13565-905, SP (Brazil); Prokofiev, E. [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, São Carlos 13565-905, SP (Brazil); Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 12 K. Marx Str., Ufa 450000 (Russian Federation); Sanches, L.F.R. [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, São Carlos 13565-905, SP (Brazil); Polyakova, V. [Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 12 K. Marx Str., Ufa 450000 (Russian Federation); Valiev, R.Z., E-mail: rzvaliev@mail.rb.ru [Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 12 K. Marx Str., Ufa 450000 (Russian Federation); Botta, W.J.; Junior, A.M.J.; Bolfarini, C. [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos, Rod. Washington Luiz, km 235, São Carlos 13565-905, SP (Brazil)

    2015-09-15

    Highlights: • Ultrafine-grained titanium alloys is a good choice for biomedical applications. • Acid phosphoric treatment enhances bioactivity of Ti–6Al–7Nb alloy. • Apatite precipitation was increased in ultrafine-grained after surface modification. - Abstract: Ti–6Al–7Nb containing harmless for tissues niobium can be a good choice replacing Ti–6Al–4V for orthopedic implants application. Formation of ultrafine-grained (UFG) structure in metals and alloys by severe plastic deformation (SPD) techniques allows for achieving unique mechanical properties. Using equal channel angular pressing (ECAP) UFG structure in Ti–6Al–7Nb alloy with an average size of grains/subgrains of 200 nm was obtained. This UFG Ti–6Al–7Nb alloy has high mechanical (ultimate tensile strength 1470 MPa) and fatigue properties, suitable for practical application. Additionally, surface modifications of titanium alloys aim induce specific responses on osteoblastic cells after implantation. Chemical surface treatments are simple methods to obtain a bioactive for apatite precipitation surface. Phosphoric acid etching combined or not with alkaline treatment presented bioactivity after seven days soaked in simulated body fluid (SBF) solution.

  3. Study of real time detection and size distribution measurement of ultrafine aerosol with a particle growth system (PGS)

    Energy Technology Data Exchange (ETDEWEB)

    Rebours, A.

    1994-06-29

    First, the theoretical knowledge on condensation phenomena of a supersaturated vapor in a cylindrical duct where an ultrafine aerosol of nanometers size is flowing, is recalled. Then, a Particle Growth-System (PGS) of original design is developed: the aerosol is confined in a region with a uniform vapor supersaturation profile. When imperfectly filtered atmospheric air is used as source of condensation nuclei, the produced droplets are found to be monodisperse. Therefore, our PGS offers a simple method of calibrating Optical Particle Counters because the size distribution of theses droplets is controlled. After an experimental study validated by a theoretical model, we establish that, under certain supersaturation conditions, the droplet size in our PGS is a function of ultrafine particle size on which the vapor condenses. Furthermore, when the sampled aerosol is constituted of an ultrafine fraction and a fine fraction, we show that the size distribution of the droplets that come out from the PGS is bimodal too. Finally, a simple redesign of our fluids inlet system should reduce particles losses in the PGS due to brownian diffusion and, in that manner improve their detection. (author). 72 refs., 46 figs., 8 tabs., 4 appends.

  4. Numerical simulation of two-phase multicomponent flow with reactive transport in porous media

    International Nuclear Information System (INIS)

    Vostrikov, Viatcheslav

    2014-01-01

    . We thus opted for a decoupled approach, where the two-phase flow and reactive transport subsystems are solved sequentially. The main advantage of this approach is that it lets us reuse well tested software codes to solve these two subsystems. Another advantage is that we avoid having to solve a very large, and possibly ill-conditioned system of equations at each time-step. The codes we have used for both the two-phase two-component flow and the reactive transport problems are described in details in Chapter 3, as they will be essential ingredients in the solution process. The overall framework we have used is the DuMu X library (a free and open-source simulator for flow and transport processes in porous media). The two-phase flow solver was already present in the framework (though we have validated its use). To solve the reactive transport problem, we have implemented a new module in the DuMu X framework that solves a single phase multicomponent problem, and we have coupled it with a locally developed code for chemical equilibrium call ChemEqLib, through a sequential iterative approach. In Chapter 4, we discuss the decoupled solution method, based on the individual codes described previously. A possible drawback of the approach is that some accuracy may be lost in the decoupling process. For this reason, we have gone into much detail when presenting the decoupling procedure, so that the additional approximation so introduced will be visible. We then present the high level module that implements the sequential coupling procedure. We describe the method used, and show its validation on test examples from the literature that describe typical CO 2 storage scenarios. (author) [fr

  5. Source apportionment of fine (PM1.8) and ultrafine (PM0.1) airborne particulate matter during a severe winter pollution episode.

    Science.gov (United States)

    Kleeman, Michael J; Riddle, Sarah G; Robert, Michael A; Jakober, Chris A; Fine, Phillip M; Hays, Michael D; Schauer, James J; Hannigan, Michael P

    2009-01-15

    Size-resolved samples of airborne particulate matter (PM) collected during a severe winter pollution episode at three sites in the San Joaquin Valley of California were extracted with organic solvents and analyzed for detailed organic compounds using GC-MS. Six particle size fractions were characterized with diameter (Dp) < 1.8 microm; the smallest size fraction was 0.056 < Dp < 0.1 microm which accounts for the majority of the mass in the ultrafine (PM0.1) size range. Source profiles for ultrafine particles developed during previous studies were applied to the measurements at each sampling site to calculate source contributions to organic carbon (OC) and elemental carbon (EC) concentrations. Ultrafine EC concentrations ranged from 0.03 microg m(-3) during the daytime to 0.18 microg m(-3) during the nighttime. Gasoline fuel, diesel fuel, and lubricating oil combustion products accounted for the majority of the ultrafine EC concentrations, with relatively minor contributions from biomass combustion and meat cooking. Ultrafine OC concentrations ranged from 0.2 microg m(-3) during the daytime to 0.8 microg m(-3) during the nighttime. Wood combustion was found to be the largest source of ultrafine OC. Meat cooking was also identified as a significant potential source of PM0.1 mass but further study is required to verify the contributions from this source. Gasoline fuel, diesel fuel, and lubricating oil combustion products made minor contributions to PM0.1 OC mass. Total ultrafine particulate matter concentrations were dominated by contributions from wood combustion and meat cooking during the current study. Future inhalation exposure studies may wish to target these sources as potential causes of adverse health effects.

  6. Fine and Ultrafine Particles from Combustion Sources - Investigations with in-situ techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pagels, Joakim

    2005-04-01

    Fine airborne particles are associated with adverse health effects in the human population. The aim of this research was to develop and evaluate methods for in-situ characterisation of fine and ultrafine particles and to determine their deposition in the human airways. The aim was also to increase knowledge about health and environmentally relevant properties of aerosols from biomass combustion and selected indoor sources. The methods include instrumental techniques such as Scanning Mobility Particle Sizer (SMPS), Electrical Low-Pressure Impactor (ELPI), Aerodynamic Particle Sizer (APS) and Tandem Differential Mobility Analysers (TDMA) based on volatility and hygroscopic growth. Filter samplers and impactors were used for collecting particles on substrates for subsequent chemical analysis. Emissions from local district heating plants (0.5-12 MW), based on moving grate combustion of woody fuels, were sampled with a dilution system and characterised. Particles from the indoor sources of cigarettes, incense and candles were examined in the laboratory by using an airtight 22 m{sup 3} stainless steel chamber. A set-up to determine respiratory deposition in humans was constructed. It was automatised and uses an electrical mobility spectrometer with an improved inversion algorithm to perform fast measurements of particles of different sizes in the inhaled and exhaled air. It was evaluated on human test-persons. The investigated biomass combustion sources emit high concentrations of fine and ultrafine particles. The chemical composition is dominated by KCl and K{sub 2}SO{sub 4}; Zn, Cd and Pb were also quantified. Elemental carbon was identified in particles larger than 150 nm during periods of incomplete combustion. The particle concentration depends on the fuel ash content and the combustion efficiency. The aerosol is essentially internally mixed with hygroscopic growth factors significantly higher than reported for diesel exhaust and environmental tobacco smoke. The

  7. Macro-Raman spectroscopy for bulk composition and homogeneity analysis of multi-component pharmaceutical powders.

    Science.gov (United States)

    Wang, Hui; Barona, David; Oladepo, Sulayman; Williams, Lisa; Hoe, Susan; Lechuga-Ballesteros, David; Vehring, Reinhard

    2017-07-15

    A new macro-Raman system equipped with a motorized translational sample stage and low-frequency shift capabilities was developed for bulk composition and homogeneity analysis of multi-component pharmaceutical powders. Different sampling methods including single spot and scanning measurement were compared. It was found that increasing sample volumes significantly improved the precision of quantitative composition analysis, especially for poorly mixed powders. The multi-pass cavity of the macro-Raman system increased effective sample volumes by 20 times from the sample volume defined by the collection optics, i.e., from 0.02μL to about 0.4μL. A stochastic model simulating the random sampling process of polydisperse microparticles was used to predict the sampling errors for a specific sample volume. Comparison of fluticasone propionate mass fractions of the commercial products Flixotide ® 250 and Seretide ® 500 simulated for different sampling volumes with experimentally measured compositions verified that the effective sample volume of a single point macro-Raman measurement in the multi-pass cavity of this instrument was between 0.3μL and 0.5μL. The macro-Raman system was also successfully used for blend uniformity analysis. It was concluded that demixing occurred in the binary mixture of l-leucine and d-mannitol from the observation that the sampling errors indicated by the standard deviations of measured leucine mass fractions increased during mixing, and the standard deviation values were all larger than the theoretical lower limit determined by the simulation. Since sample volume was shown to have a significant impact on measured homogeneity characteristics, it was concluded that powder homogeneity analysis results, i.e., the mean of individual test results and absolute and relative standard deviations, must be presented together with the effective sample volumes of the applied testing techniques for any measurement of powder homogeneity to be fully

  8. Modelisation de la synthese reactive de poudres ultrafines dans un reacteur a plasma thermique

    Science.gov (United States)

    Desilets, Martin

    La presente these s'inscrit dans le cadre de la modelisation mathematique des ecoulements a plasmas thermiques inertes et reactifs. Elle vise plus precisement a combler les lacunes des modeles existants en portant une attention particuliere aux phenomenes de transport multicomposant et a la prediction des transformations chimiques. Pour repondre a ces attentes et ainsi poursuivre le developpement dans ce domaine, un modele global a ete developpe. Il combine la resolution d'equations conservatives pour la masse, l'energie et le momentum. La generation d'un plasma inductif (h.f ) y est traitee au moyen d'equations representant les champs electromagnetiques. La nucleation et la croissance de poudres ultrafines sont incluses dans le modele via l'analyse des principaux moments de la distribution des tailles de particules. Enfin, tous les phenomenes physico-chimiques d'importance dans un milieu comme les plasmas thermiques, de meme que lem interactions, sont consideres. Le modele est applique ici a l'analyse de trois problematiques differentes et complementaires. La premiere concerne l'etude du melange gazeux d'un jet froid (He, N 2 ou O2), injecte au coeur d'une decharge d'argon/hydrogene ou d'argon/oxygene. La comparaison des predictions du modele avec des mesures experimentales obtenues par une sonde enthalpique permet une validation partielle de ce dernier. La deuxieme problematique a trait a l'etude numerique de la pyrolyse du methane en reacteur a plasma h.f. Elle met en evidence les difficultes de convergence de la methode numerique lorsque appliquee a la resolution d'ecoulements reactifs a haute temperature. Finalement, le dernier sujet aborde dans cette these, soit l'analyse systematique des principales conditions d'operation d'un reacteur h.f utilise pour la synthese reactive de poudres ultrafines de silicium, engage tous les elements theoriques du modele. Il implique en effet la decomposition thermique d'un precurseur gazeux, le tetrachlorure de silicium, la

  9. Estimate of main local sources to ambient ultrafine particle number concentrations in an urban area

    Science.gov (United States)

    Rahman, Md Mahmudur; Mazaheri, Mandana; Clifford, Sam; Morawska, Lidia

    2017-09-01

    Quantifying and apportioning the contribution of a range of sources to ultrafine particles (UFPs, D urban environments. Although vehicular emissions have long been considered one of the major sources of ultrafine particles in urban areas, the contribution of other major urban sources is not yet fully understood. This paper aims to determine and quantify the contribution of local ground traffic, nucleated particle (NP) formation and distant non-traffic (e.g. airport, oil refineries, and seaport) sources to the total ambient particle number concentration (PNC) in a busy, inner-city area in Brisbane, Australia using Bayesian statistical modelling and other exploratory tools. The Bayesian model was trained on the PNC data on days where NP formations were known to have not occurred, hourly traffic counts, solar radiation data, and smooth daily trend. The model was applied to apportion and quantify the contribution of NP formations and local traffic and non-traffic sources to UFPs. The data analysis incorporated long-term measured time-series of total PNC (D ≥ 6 nm), particle number size distributions (PSD, D = 8 to 400 nm), PM2.5, PM10, NOx, CO, meteorological parameters and traffic counts at a stationary monitoring site. The developed Bayesian model showed reliable predictive performances in quantifying the contribution of NP formation events to UFPs (up to 4 × 104 particles cm- 3), with a significant day to day variability. The model identified potential NP formation and no-formations days based on PNC data and quantified the sources contribution to UFPs. Exploratory statistical analyses show that total mean PNC during the middle of the day was up to 32% higher than during peak morning and evening traffic periods, which were associated with NP formation events. The majority of UFPs measured during the peak traffic and NP formation periods were between 30-100 nm and smaller than 30 nm, respectively. To date, this is the first application of Bayesian model to

  10. Chemical, dimensional and morphological ultrafine particle characterization from a waste-to-energy plant.

    Science.gov (United States)

    Buonanno, Giorgio; Stabile, Luca; Avino, Pasquale; Belluso, Elena

    2011-11-01

    Waste combustion processes are responsible of particles and gaseous emissions. Referring to the particle emission, in the last years specific attention was paid to ultrafine particles (UFPs, diameter less than 0.1 μm), mainly emitted by combustion processes. In fact, recent findings of toxicological and epidemiological studies indicate that fine and ultrafine particles could represent a risk for health and environment. Therefore, it is necessary to quantify particle emissions from incinerators also to perform an exposure assessment for the human populations living in their surrounding areas. To these purposes, in the present work an experimental campaign aimed to monitor UFPs was carried out at the incineration plant in San Vittore del Lazio (Italy). Particle size distributions and total concentrations were measured both at the stack and before the fabric filter inlet in order to evaluate the removal efficiency of the filter in terms of UFPs. A chemical characterization of UFPs in terms of heavy metal concentration was performed through a nuclear method, i.e., Instrumental Neutron Activation Analysis (INAA), as well as a mineralogical investigation was carried out through a Transmission Electron Microscope (TEM) equipped with an Energy Dispersive Spectrometer (EDS) in order to evaluate shape, crystalline state and mineral compound of sampled particles. Maximum values of 2.7 × 10(7) part. cm(-3) and 2.0 × 10(3) part. cm(-3) were found, respectively, for number concentration before and after the fabric filter showing a very high efficiency in particle removing by the fabric filter. With regard to heavy metal concentrations, the elements with higher boiling temperature present higher concentrations at lower diameters showing a not complete evaporation in the combustion section and the consequent condensation of semi-volatile compounds on solid nuclei. In terms of mineralogical and morphological analysis, the most abundant compounds found in samples collected before

  11. Effect of char on the combustion process of multicomponent bio-fuel

    NARCIS (Netherlands)

    Mahmoudi, Amir Houshang; Pozarlik, A.K.; van der Weide, E.; Kersten, S.R.A.; Luding, S.; Brem, G.

    2018-01-01

    Combustion of pyrolysis oil has attracted many attention in recent years as a renewable and environmental friendly fuel. However, pyrolysis oil as an multi-component fuel has some differences compared to conventional fossil fuels. One of the main differences is the formation of solid char in the

  12. A Multicomponent UV Analysis of ["alpha"]- and ["beta"]-Acids in Hops

    Science.gov (United States)

    Egts, Haley; Durben, Dan J.; Dixson, John A.; Zehfus, Micheal H.

    2012-01-01

    A method is presented for the determination of ["alpha"]- and ["beta"]-acids (humulones and lupulones) in a hops sample using a multicomponent UV spectroscopic analysis of a methanolic hop extract. When compared with standard methods, this lab can be considered "greener" because it uses smaller volumes of safer solvents (methanol instead of…

  13. A new and efficient multicomponent solid-phase synthesis of 2-acylaminomethylthiazoles

    NARCIS (Netherlands)

    Henkel, Bernd; Sax, Michael; Dömling, Alexander

    2003-01-01

    A new multicomponent reaction (MCR) for the preparation of 2-substituted thiazole libraries using Rink amide resin is described. Thiazoles are assembled in a one-pot MCR of a thiocarboxylic acid, aldehyde, 3-(N,N-dimethylamino)-2-isocyanoacrylate with a resin-bound primary amine. Aliphatic and

  14. New macrocycles with potent antituberculosis activity accessed by one-pot multicomponent reactions

    NARCIS (Netherlands)

    Kim, D.; Huang, Y.; Wang, K.; Doemling, A.

    Based on modeling studies, we hypothesized that tylosin derivatives without formyl group should rather adopt an erythromycin-like binding mode to the ribosome. Twenty four 16-membered macrocyclic compounds were accessed by multicomponent reactions (Gewald, Ugi) of tylosin and investigated for their

  15. Lattice Boltzmann based multicomponent reactive transport model coupled with geochemical solver for scale simulations

    NARCIS (Netherlands)

    Patel, R.A.; Perko, J.; Jaques, D.; De Schutter, G.; Ye, G.; Van Breugel, K.

    2013-01-01

    A Lattice Boltzmann (LB) based reactive transport model intended to capture reactions and solid phase changes occurring at the pore scale is presented. The proposed approach uses LB method to compute multi component mass transport. The LB multi-component transport model is then coupled with the

  16. Using Data to Individualize a Multicomponent, Technology-Based Self-Monitoring Intervention

    Science.gov (United States)

    Bruhn, Allison Leigh; Vogelgesang, Kari; Fernando, Josephine; Lugo, Wilbeth

    2016-01-01

    Technology in schools is abundant as is the call for evidence-based interventions for students who need additional support to be successful. One promising use of technology is for self-monitoring interventions aimed at improving classroom behavior. In this study, two middle school students with disabilities used a multicomponent, self-monitoring…

  17. Equilibrium properties of a multi-component ionic mixture I. Sum rules for correlation functions

    NARCIS (Netherlands)

    van Wonderen, A.J.; Suttorp, L.G.

    1987-01-01

    Equilibrium statistical methods are used to derive sum rules for two- and three-particle correlation functions of a multi-component ionic mixture. Some of these rules are general consequences of the electrostatic character of the interaction, whereas others depend on specific thermodynamic

  18. Composition Dependence of Water Permeation Across Multicomponent Gel-Phase Bilayers

    NARCIS (Netherlands)

    Hartkamp, R.M.; Moore, Timothy C.; Iacovella, Christopher R.; Thompson, Michael A.; Bulsara, Pallav A.; Moore, David J.; McCabe, Clare

    2018-01-01

    The permeability of multicomponent phospholipid bilayers in the gel phase is investigated via molecular dynamics simulation. The physical role of the different molecules is probed by comparing multiple mixed-component bilayers containing distearylphosphatidylcholine (DSPC) with varying amounts of

  19. Simultaneous assembly of the β-lactam and thiazole moiety by a new multicomponent reaction

    NARCIS (Netherlands)

    Kolb, Jürgen; Beck, Barbara; Dömling, Alexander

    2002-01-01

    A novel multicomponent reaction of β-aminothiocarboxylic acids, aldehydes, and 3-dimethylamino-2-isocyanoacylate is described. During the course of this reaction two heterocyclic moieties, a thiazole and a β-lactam ring, are formed simultaneously and under mild conditions. The increase in molecular

  20. Development of responder criteria for multicomponent non-pharmacological treatment in fibromyalgia

    NARCIS (Netherlands)

    Vervoort, V.M.; Vriezekolk, J.E.; Ende, C.H.M. van den

    2017-01-01

    OBJECTIVES: There is a need to identify individual treatment success in patients with fibromyalgia (FM) who received non-pharmacological treatment. The present study described responder criteria for multicomponent non-pharmacological treatment in FM, and estimated and compared their sensitivity and