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Sample records for nanoparticle pollutants interfere

  1. Interference between nanoparticles and metal homeostasis

    International Nuclear Information System (INIS)

    Petit, A N; Catty, P; Charbonnier, P; Cuillel, M; Mintz, E; Moulis, J M; Niviere, V; Choudens, S Ollagnier de; Garcia, C Aude; Candeias, S; Chevallet, M; Collin-Faure, V; Lelong, C; Luche, S; Rabilloud, T; Casanova, A; Herlin-Boime, N; Douki, T; Ravanat, J L; Sauvaigo, S

    2011-01-01

    The TiO 2 nanoparticles (NPs) are now produced abundantly and widely used in a variety of consumer products. Due to the important increase in the production of TiO 2 -NPs, potential widespread exposure of humans and environment may occur during both the manufacturing process and final use. Therefore, the potential toxicity of TiO 2 -NPs on human health and environment has attracted particular attention. Unfortunately, the results of the large number of studies on the toxicity of TiO 2 -NPs differ significantly, mainly due to an incomplete characterization of the used nanomaterials in terms of size, shape and crystalline structure and to their unknown state of agglomeration/aggregation. The purpose of our project entitled NanoBioMet is to investigate if interferences between nanoparticles and metal homeostasis could be observed and to study the toxicity mechanisms of TiO 2 -NPs with well-characterized physicochemical parameters, using proteomic and molecular approaches. A perturbation of metal homeostasis will be evaluated upon TiO 2 -NPs exposure which could generate reactive oxygen species (ROS) production. Moreover, oxidative stress consequences such as DNA damage and lipid peroxidation will be studied. The toxicity of TiO 2 -NPs of different sizes and crystalline structures will be evaluated both in prokaryotic (E. coli) and eukaryotic cells (A549 human pneumocytes, macrophages, and hepatocytes). First results of the project will be presented concerning the dispersion of TiO 2 -NPs in bacterial medium, proteomic studies on total extracts of macrophages and genotoxicity on pneumocytes.

  2. Widespread nanoparticle-assay interference: implications for nanotoxicity testing.

    Science.gov (United States)

    Ong, Kimberly J; MacCormack, Tyson J; Clark, Rhett J; Ede, James D; Ortega, Van A; Felix, Lindsey C; Dang, Michael K M; Ma, Guibin; Fenniri, Hicham; Veinot, Jonathan G C; Goss, Greg G

    2014-01-01

    The evaluation of engineered nanomaterial safety has been hindered by conflicting reports demonstrating differential degrees of toxicity with the same nanoparticles. The unique properties of these materials increase the likelihood that they will interfere with analytical techniques, which may contribute to this phenomenon. We tested the potential for: 1) nanoparticle intrinsic fluorescence/absorbance, 2) interactions between nanoparticles and assay components, and 3) the effects of adding both nanoparticles and analytes to an assay, to interfere with the accurate assessment of toxicity. Silicon, cadmium selenide, titanium dioxide, and helical rosette nanotubes each affected at least one of the six assays tested, resulting in either substantial over- or under-estimations of toxicity. Simulation of realistic assay conditions revealed that interference could not be predicted solely by interactions between nanoparticles and assay components. Moreover, the nature and degree of interference cannot be predicted solely based on our current understanding of nanomaterial behaviour. A literature survey indicated that ca. 95% of papers from 2010 using biochemical techniques to assess nanotoxicity did not account for potential interference of nanoparticles, and this number had not substantially improved in 2012. We provide guidance on avoiding and/or controlling for such interference to improve the accuracy of nanotoxicity assessments.

  3. Widespread nanoparticle-assay interference: implications for nanotoxicity testing.

    Directory of Open Access Journals (Sweden)

    Kimberly J Ong

    Full Text Available The evaluation of engineered nanomaterial safety has been hindered by conflicting reports demonstrating differential degrees of toxicity with the same nanoparticles. The unique properties of these materials increase the likelihood that they will interfere with analytical techniques, which may contribute to this phenomenon. We tested the potential for: 1 nanoparticle intrinsic fluorescence/absorbance, 2 interactions between nanoparticles and assay components, and 3 the effects of adding both nanoparticles and analytes to an assay, to interfere with the accurate assessment of toxicity. Silicon, cadmium selenide, titanium dioxide, and helical rosette nanotubes each affected at least one of the six assays tested, resulting in either substantial over- or under-estimations of toxicity. Simulation of realistic assay conditions revealed that interference could not be predicted solely by interactions between nanoparticles and assay components. Moreover, the nature and degree of interference cannot be predicted solely based on our current understanding of nanomaterial behaviour. A literature survey indicated that ca. 95% of papers from 2010 using biochemical techniques to assess nanotoxicity did not account for potential interference of nanoparticles, and this number had not substantially improved in 2012. We provide guidance on avoiding and/or controlling for such interference to improve the accuracy of nanotoxicity assessments.

  4. Decontaminating soil organic pollutants with manufactured nanoparticles.

    Science.gov (United States)

    Li, Qi; Chen, Xijuan; Zhuang, Jie; Chen, Xin

    2016-06-01

    Organic pollutants in soils might threaten the environmental and human health. Manufactured nanoparticles are capable to reduce this risk efficiently due to their relatively large capacity of sorption and degradation of organic pollutants. Stability, mobility, and reactivity of nanoparticles are prerequisites for their efficacy in soil remediation. On the basis of a brief introduction of these issues, this review provides a comprehensive summary of the application and effectiveness of various types of manufactured nanoparticles for removing organic pollutants from soil. The main categories of nanoparticles include iron (oxides), titanium dioxide, carbonaceous, palladium, and amphiphilic polymeric nanoparticles. Their advantages (e.g., unique properties and high sorption capacity) and disadvantages (e.g., high cost and low recovery) for soil remediation are discussed with respect to the characteristics of organic pollutants. The factors that influence the decontamination effects, such as properties, surfactants, solution chemistry, and soil organic matter, are addressed.

  5. Interferences of Silica Nanoparticles in Green Fluorescent Protein Folding Processes.

    Science.gov (United States)

    Klein, Géraldine; Devineau, Stéphanie; Aude, Jean Christophe; Boulard, Yves; Pasquier, Hélène; Labarre, Jean; Pin, Serge; Renault, Jean Philippe

    2016-01-12

    We investigated the relationship between unfolded proteins, silica nanoparticles and chaperonin to determine whether unfolded proteins could stick to silica surfaces and how this process could impair heat shock protein activity. The HSP60 catalyzed green fluorescent protein (GFP) folding was used as a model system. The adsorption isotherms and adsorption kinetics of denatured GFP were measured, showing that denaturation increases GFP affinity for silica surfaces. This affinity is maintained even if the surfaces are covered by a protein corona and allows silica NPs to interfere directly with GFP folding by trapping it in its unstructured state. We determined also the adsorption isotherms of HSP60 and its chaperonin activity once adsorbed, showing that SiO2 NP can interfere also indirectly with protein folding through chaperonin trapping and inhibition. This inhibition is specifically efficient when NPs are covered first with a layer of unfolded proteins. These results highlight for the first time the antichaperonin activity of silica NPs and ask new questions about the toxicity of such misfolded proteins/nanoparticles assembly toward cells.

  6. Vectorization by nanoparticles decreases the overall toxicity of airborne pollutants.

    Science.gov (United States)

    Carpentier, Rodolphe; Platel, Anne; Maiz-Gregores, Helena; Nesslany, Fabrice; Betbeder, Didier

    2017-01-01

    Atmospheric pollution is mainly composed of volatile pollutants and particulate matter that strongly interact. However, their specific roles in the induction of cellular toxicity, in particular the impact of the vectorization of atmospheric pollutants by ultrafine particles, remains to be fully elucidated. For this purpose, non-toxic poly-lactic co-glycolic acid (PLGA) nanoparticles were synthesized and three pollutants (benzo(a)pyrene, naphthalene and di-ethyl-hexyl-phthalate) were adsorbed on the surface of the nanoparticles in order to evaluate the toxicity (cytotoxicity, genotoxicity and ROS induction) of these complexes to a human airway epithelial cell line. The adsorption of the pollutants onto the nanoparticles was confirmed by HPLC analysis. Interestingly, the cytotoxicity assays (MTT, LDH and CellTox Green) clearly demonstrated that the vectorization by nanoparticles decreases the toxicity of the adsorbed pollutants. Genotoxicity was assessed by the micronucleus test and the comet assay and showed no increase in primary DNA damage or in chromosomal aberrations of nanoparticle vectorized pollutants. Neither cytotoxicity nor genotoxicity was correlated with ROS induction. To conclude, our results indicate that the vectorization of pollutants by nanoparticles does not potentiate the toxicity of the pollutants studied and that, on the contrary, adsorption onto nanoparticles could protect cells against pollutants' toxicity.

  7. Vectorization by nanoparticles decreases the overall toxicity of airborne pollutants.

    Directory of Open Access Journals (Sweden)

    Rodolphe Carpentier

    Full Text Available Atmospheric pollution is mainly composed of volatile pollutants and particulate matter that strongly interact. However, their specific roles in the induction of cellular toxicity, in particular the impact of the vectorization of atmospheric pollutants by ultrafine particles, remains to be fully elucidated. For this purpose, non-toxic poly-lactic co-glycolic acid (PLGA nanoparticles were synthesized and three pollutants (benzo(apyrene, naphthalene and di-ethyl-hexyl-phthalate were adsorbed on the surface of the nanoparticles in order to evaluate the toxicity (cytotoxicity, genotoxicity and ROS induction of these complexes to a human airway epithelial cell line. The adsorption of the pollutants onto the nanoparticles was confirmed by HPLC analysis. Interestingly, the cytotoxicity assays (MTT, LDH and CellTox Green clearly demonstrated that the vectorization by nanoparticles decreases the toxicity of the adsorbed pollutants. Genotoxicity was assessed by the micronucleus test and the comet assay and showed no increase in primary DNA damage or in chromosomal aberrations of nanoparticle vectorized pollutants. Neither cytotoxicity nor genotoxicity was correlated with ROS induction. To conclude, our results indicate that the vectorization of pollutants by nanoparticles does not potentiate the toxicity of the pollutants studied and that, on the contrary, adsorption onto nanoparticles could protect cells against pollutants' toxicity.

  8. Nanoparticle-organic pollutant interaction dataset

    Data.gov (United States)

    U.S. Environmental Protection Agency — Dataset presents concentrations of organic pollutants, such as polyaromatic hydrocarbon compounds, in water samples. Water samples of known volume and concentration...

  9. Wavelength-Dependent Differential Interference Contrast Microscopy: Selectively Imaging Nanoparticle Probes in Live Cells

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei; Wang, Gufeng; Fang, Ning; and Yeung, Edward S.

    2009-11-15

    Gold and silver nanoparticles display extraordinarily large apparent refractive indices near their plasmon resonance (PR) wavelengths. These nanoparticles show good contrast in a narrow spectral band but are poorly resolved at other wavelengths in differential interference contrast (DIC) microscopy. The wavelength dependence of DIC contrast of gold/silver nanoparticles is interpreted in terms of Mie's theory and DIC working principles. We further exploit this wavelength dependence by modifying a DIC microscope to enable simultaneous imaging at two wavelengths. We demonstrate that gold/silver nanoparticles immobilized on the same glass slides through hybridization can be differentiated and imaged separately. High-contrast, video-rate images of living cells can be recorded both with and without illuminating the gold nanoparticle probes, providing definitive probe identification. Dual-wavelength DIC microscopy thus presents a new approach to the simultaneous detection of multiple probes of interest for high-speed live-cell imaging.

  10. Rapid sensing of melamine in milk by interference green synthesis of silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Varun, S.; Kiruba Daniel, S.C.G.; Gorthi, Sai Siva, E-mail: saisiva.gorthi@iap.iisc.ernet.in

    2017-05-01

    A highly sensitive, selective, and rapid interference green synthesis based determination of potential milk adulterant melamine has been reported here. Melamine is a nitrogenous compound added to milk for mimicking proteins, consumption of which leads to kidney stones and renal failures. Melamine interacts with ascorbic acid (AA) through strong hydrogen-bonding interactions, thus resulting in an interference/interruption in the formation of silver (Ag) nanoparticles which was confirmed by UV–Vis spectroscopy and Transmission Electron Microscopy (TEM). The corresponding benchmark validations for melamine spiked milk samples were performed using High Performance Liquid Chromatography (HPLC). This interference in the formation of Ag nanoparticles resulted in color change that varies with concentration of melamine, thereby enabling in-situ rapid sensing of melamine from milk to a lower limit of 0.1 ppm with a linear correlation coefficient of 0.9908. - Highlights: • Rapid detection of milk adulterant melamine based on interference green synthesis. • Green chemical ascorbic acid used as the reducing agent for interference sensing. • Enabling in-situ sensing of melamine from milk with a limit of detection of 0.1 ppm. • Presence of analyte inhibits the nanoparticle formation.

  11. Use of electrochemical sensors for measurement of air pollution: correcting interference response and validating measurements

    Science.gov (United States)

    Cross, Eben S.; Williams, Leah R.; Lewis, David K.; Magoon, Gregory R.; Onasch, Timothy B.; Kaminsky, Michael L.; Worsnop, Douglas R.; Jayne, John T.

    2017-09-01

    The environments in which we live, work, and play are subject to enormous variability in air pollutant concentrations. To adequately characterize air quality (AQ), measurements must be fast (real time), scalable, and reliable (with known accuracy, precision, and stability over time). Lower-cost air-quality-sensor technologies offer new opportunities for fast and distributed measurements, but a persistent characterization gap remains when it comes to evaluating sensor performance under realistic environmental sampling conditions. This limits our ability to inform the public about pollution sources and inspire policy makers to address environmental justice issues related to air quality. In this paper, initial results obtained with a recently developed lower-cost air-quality-sensor system are reported. In this project, data were acquired with the ARISense integrated sensor package over a 4.5-month time interval during which the sensor system was co-located with a state-operated (Massachusetts, USA) air quality monitoring station equipped with reference instrumentation measuring the same pollutant species. This paper focuses on validating electrochemical (EC) sensor measurements of CO, NO, NO2, and O3 at an urban neighborhood site with pollutant concentration ranges (parts per billion by volume, ppb; 5 min averages, ±1σ): [CO] = 231 ± 116 ppb (spanning 84-1706 ppb), [NO] = 6.1 ± 11.5 ppb (spanning 0-209 ppb), [NO2] = 11.7 ± 8.3 ppb (spanning 0-71 ppb), and [O3] = 23.2 ± 12.5 ppb (spanning 0-99 ppb). Through the use of high-dimensional model representation (HDMR), we show that interference effects derived from the variable ambient gas concentration mix and changing environmental conditions over three seasons (sensor flow-cell temperature = 23.4 ± 8.5 °C, spanning 4.1 to 45.2 °C; and relative humidity = 50.1 ± 15.3 %, spanning 9.8-79.9 %) can be effectively modeled for the Alphasense CO-B4, NO-B4, NO2-B43F, and Ox-B421 sensors, yielding (5 min average) root

  12. High temperature radio-frequency superconducting quantum interference device system for detection of magnetic nanoparticles

    International Nuclear Information System (INIS)

    Pretzell, Alf

    2012-01-01

    This doctoral thesis was aimed at establishing a set-up with high-temperature superconductor (HTS) radio-frequency (rf) superconducting quantum interference device (SQUID) technology for the detection of magnetic nanoparticles and in particular for testing applications of magnetic nanoparticle immunoassays. It was part of the EU-project ''Biodiagnostics'' running from 2005 to 2008. The method of magnetic binding assays was developed as an alternative to other methods of concentration determination like enzyme linked immunosorbent assay (ELISA), or fluorescent immunoassay. The ELISA has sensitivities down to analyte-concentrations of pg/ml. Multiple incubation and washing steps have to be performed for these techniques, the analyte has to diffuse to the site of binding. The magnetic assay uses magnetic nanoparticles as markers for the substance to be detected. It is being explored by current research and shows similar sensitivity compared to ELISA but in contrast - does not need any washing and can be read out directly after binding - can be applied in solution with opaque media, e.g. blood or muddy water - additionally allows magnetic separation or concentration - in combination with small magnetoresistive or Hall sensors, allows detection of only a few particles or even single beads. For medical or environmental samples, maybe opaque and containing a multitude of substances, it would be advantageous to devise an instrument, which allows to be read out quickly and with high sensitivity. Due to the mentioned items the magnetic assay might be a possibility here.

  13. Adsorption of environmental pollutants using magnetic hybrid nanoparticles modified with β-cyclodextrin

    International Nuclear Information System (INIS)

    Wang, Niejun; Zhou, Lilin; Guo, Jun; Ye, Qiquan; Lin, Jin-Ming; Yuan, Jinying

    2014-01-01

    Graft through strategy was utilized to coat magnetic Fe 3 O 4 nanoparticles with poly(glycidyl methacrylate) using ordinary radical polymerization and then β-cyclodextrin was linked onto the surface of nanoparticles. With these nanoparticles modified with cyclodextrin groups, adsorption of two model environmental pollutants, bisphenol A and copper ions, was studied. Host–guest interactions between cyclodextrin and aromatic molecules had a great contribution to the adsorption of bisphenol A, while multiple hydroxyls of cyclodextrin also helped the adsorption of copper ions. These magnetic nanoparticles could be applied in the elimination, enrichment and detection of some environmental pollutants.

  14. Use of electrochemical sensors for measurement of air pollution: correcting interference response and validating measurements

    Directory of Open Access Journals (Sweden)

    E. S. Cross

    2017-09-01

    Full Text Available The environments in which we live, work, and play are subject to enormous variability in air pollutant concentrations. To adequately characterize air quality (AQ, measurements must be fast (real time, scalable, and reliable (with known accuracy, precision, and stability over time. Lower-cost air-quality-sensor technologies offer new opportunities for fast and distributed measurements, but a persistent characterization gap remains when it comes to evaluating sensor performance under realistic environmental sampling conditions. This limits our ability to inform the public about pollution sources and inspire policy makers to address environmental justice issues related to air quality. In this paper, initial results obtained with a recently developed lower-cost air-quality-sensor system are reported. In this project, data were acquired with the ARISense integrated sensor package over a 4.5-month time interval during which the sensor system was co-located with a state-operated (Massachusetts, USA air quality monitoring station equipped with reference instrumentation measuring the same pollutant species. This paper focuses on validating electrochemical (EC sensor measurements of CO, NO, NO2, and O3 at an urban neighborhood site with pollutant concentration ranges (parts per billion by volume, ppb; 5 min averages, ±1σ: [CO]  =  231 ± 116 ppb (spanning 84–1706 ppb, [NO]  =  6.1 ± 11.5 ppb (spanning 0–209 ppb, [NO2]  =  11.7 ± 8.3 ppb (spanning 0–71 ppb, and [O3]  =  23.2 ± 12.5 ppb (spanning 0–99 ppb. Through the use of high-dimensional model representation (HDMR, we show that interference effects derived from the variable ambient gas concentration mix and changing environmental conditions over three seasons (sensor flow-cell temperature  =  23.4 ± 8.5 °C, spanning 4.1 to 45.2 °C; and relative humidity  =  50.1 ± 15.3 %, spanning 9.8–79.9

  15. Nanoparticles with photoinduced precipitation for the extraction of pollutants from water and soil.

    Science.gov (United States)

    Brandl, Ferdinand; Bertrand, Nicolas; Lima, Eliana Martins; Langer, Robert

    2015-07-21

    Nanotechnology may offer fast and effective solutions for environmental clean-up. Herein, amphiphilic diblock copolymers are used to develop a platform of photosensitive core-shell nanoparticles. Irradiation with ultraviolet light removes the protective layer responsible for colloidal stability; as a result, the nanoparticles are rapidly and irreversibly converted to macroscopic aggregates. The associated phase separation allows measuring the partitioning of small molecules between the aqueous phase and nanoparticles; data suggests that interactions are enhanced by decreasing the particle size. Adsorption onto nanoparticles can be exploited to efficiently remove hydrophobic pollutants from water and contaminated soil. Preliminary in vivo experiments suggest that treatment with photocleavable nanoparticles can significantly reduce the teratogenicity of bisphenol A, triclosan and 17α-ethinyl estradiol without generating obviously toxic byproducts. Small-scale pilot experiments on wastewater, thermal printing paper and contaminated soil demonstrate the applicability of the approach.

  16. The organic air pollutant cumene hydroperoxide interferes with NO antioxidant role in rehydrating lichen

    International Nuclear Information System (INIS)

    Catalá, M.; Gasulla, F.; Pradas del Real, A.E.; García-Breijo, F.; Reig-Armiñana, J.; Barreno, E.

    2013-01-01

    Organic pollutants effects on lichens have not been addressed. Rehydration is critical for lichens, a burst of free radicals involving NO occurs. Repeated dehydrations with organic pollutants could increase oxidative damage. Our aim is to learn the effects of cumene hydroperoxide (CP) during lichen rehydration using Ramalina farinacea (L.) Ach., its photobiont Trebouxia spp. and Asterochloris erici. Confocal imaging shows intracellular ROS and NO production within myco and phycobionts, being the chloroplast the main source of free radicals. CP increases ROS, NO and lipid peroxidation and reduces chlorophyll autofluorescence, although photosynthesis remains unaffected. Concomitant NO inhibition provokes a generalized increase of ROS and a decrease in photosynthesis. Our results suggest that CP induces a compensatory hormetic response in Ramalina farinacea that could reduce the lichen's antioxidant resources after repeated desiccation-rehydration cycles. NO is important in the protection from CP. -- Highlights: •Organic pollutants could be involved in lichen decline but effects are unknown. •Cumene hydroperoxide induces a compensatory response in rehydration (hormesis). •Cumene hydroperoxide induces a delayed lipid peroxidation. •NO is involved in rehydration oxidative stress regulation under cumene hydroperoxide. •Symbionts display specific responses probably involving communication along time. -- The organic air pollutant cumene hydroperoxide induces oxidative membrane damage in the lichen Ramalina farinacea during rehydration. Nitric oxide (NO) is involved in lichen response

  17. Mussel-inspired polydopamine biopolymer decorated with magnetic nanoparticles for multiple pollutants removal

    International Nuclear Information System (INIS)

    Zhang, Shengxiao; Zhang, Yuanyuan; Bi, Guoming; Liu, Junshen; Wang, Zhigang; Xu, Qiang; Xu, Hui; Li, Xiaoyan

    2014-01-01

    Highlights: • The Fe 3 O 4 /PDA hybrid material was synthesized and characterized. • The PDA polymer was firstly applied in environmental remediation. • The Fe 3 O 4 /PDA exhibited high adsorption capacity for multiple pollutants. • Removal efficiencies of pollutants with Fe 3 O 4 /PDA were pH dependent. - Abstract: The polydopamine polymer decorated with magnetic nanoparticles (Fe 3 O 4 /PDA) was synthesized and applied for removal of multiple pollutants. The resulted Fe 3 O 4 /PDA was characterized with elemental analysis, thermo-gravimetric analyses, vibrating sample magnetometer, high resolution transmission electron microscope, Fourier transform infrared spectra, and X-ray photoelectron spectroscopy. The self-polymerization of dopamine could be completed within 8 h, and Fe 3 O 4 nanoparticles were embedded into PDA polymer. Superparamagnetism and large saturation magnetization facilitated collection of sorbents with a magnet. Based on the catechol and amine groups, the PDA polymer provided multiple interactions to combine with pollutants. To investigate the adsorption ability of Fe 3 O 4 /PDA, heavy metal ions and dyes were selected as target pollutants. The adsorption of pollutants was pH dependent due to the variation of surface charges at different solution pH. The removal efficiencies of cation pollutants enhanced with solution pH increasing, and that of anion pollutant was just the opposite. Under the optimal solution pH, the maximum adsorption capacity calculated from Langmuir adsorption isotherm for methylene blue, tartrazine, Cu 2+ , Ag + , and Hg 2+ were 204.1, 100.0, 112.9, 259.1, and 467.3 mg g −1 , respectively. The Fe 3 O 4 /PDA shows great potential for multiple pollutants removal, and this study is the first application of PDA polymer in environmental remediation

  18. Natural polymers supported copper nanoparticles for pollutants degradation

    Energy Technology Data Exchange (ETDEWEB)

    Haider, Sajjad [Department of Chemical Engineering, College of Engineering, King Saud University, P.O. Box 800, Riyadh 11421 (Saudi Arabia); Kamal, Tahseen, E-mail: tkkhan@kau.edu.sa [Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Khan, Sher Bahadar [Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Omer, Muhammad [Institute of Chemical Sciences, University of Swat, Odigram, Swat, 19130, Khyber Pakhtunkhwa (Pakistan); Haider, Adnan [Department of Nano, Medical and Polymer Materials, College of Engineering, Yeungnam University, 280 Daehak-Ro, Gyeongsan 712-749 (Korea, Republic of); Khan, Farman Ullah; Asiri, Abdullah M. [Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)

    2016-11-30

    Highlights: • Chitosan (CS) coating layer was applied on the surface of cellulose microfibers mat (CMM). • The CS coating layer was used to uptake the Copper (Cu) ions which were converted to nanoparticles. • The Cu/CS-CMM was demonstrated as catalyst in nitrophenols and cresyl blue reductions. • The rate constants for 2-nitrophenol, 4-nitrophenol and cresyl blue were 1.2 × 10{sup −3} s{sup −1}, 2.1 × 10{sup −3} s {sup −1} and, 1.3 × 10{sup −3} s{sup −1}, respectively. • The used catalyst was easily recovered by just pulling the strip from solutions. - Abstract: In this report, chitosan (CS) was adhered on cellulose microfiber mat (CMM) to prepare CS-CMM. This was used as host for copper (Cu) nanoparticles preparation. After adsorption of Cu{sup 2+} ions from an aqueous solution of CuSO{sub 4}, the metal ions entrapped in CS coating layer was treated with sodium borohydride (NaBH{sub 4}) to prepare Cu nanoparticles loaded CS-CMM (Cu/CS-CMM). Fourier transform infrared spectroscopy, and X-ray diffraction confirmed the formation of Cu/CS-CMM hybrid. Scanning electron microscopy analysis was performed to reveal the morphology of the prepared catalyst. The prepared Cu/CS-CMM was employed as a catalyst for the degradation of nitro-aromatic compounds of 2-nitrophenol (2NP) and 4-nitrophenol (4NP) as well as an organic cresyl blue (CB) dye. Remarkably, the turnover frequency in the case of 2NP and 4NP using Cu/CS-CMM reaches 103.3 and 88.6 h{sup −1}, outperforming previously reported Cu nanoparticles immobilized in hydrogel-based catalytic systems. The rate constants for 2NP, 4NP and CB were 1.2 × 10{sup −3} s{sup −1}, 2.1 × 10{sup −3} s{sup −1} and, 1.3 × 10{sup −3} s{sup −1}, respectively. Besides, we discussed the separation of the catalyst from the reaction mixture and its re-usability.

  19. Urban Air Pollution by Nanoparticles in Ostrava Region

    International Nuclear Information System (INIS)

    Zdenka, Kalicáková; Pavel, Danihelka; Vladimír, Mícka; Karel, Lach

    2013-01-01

    Air pollution harms human health and the environment. Ostrava's agglomeration and its immediate vicinity suffer regular exceeding of air pollution limits due to its geomorphologic location and present heavy industry. Maximum exceedances of air quality standards and especially PM10 which 24 hour limit value is in EU 50μg.m-3, must not be exceeded more than 35 days per year. This limit is being still often exceeded. In the year 2011 such as situation occurred 126 times. It is very important then for identify sources of air pollution to find out maximum information about air borne dust, like size distribution, chemical composition of individual size fractions, morphology of particulate matter together with other parameters like meteorological conditions, year season etc. Our measurement started two years ago. We focus on the critical situation when there are values of PM10 over a long period above the limit. In winter season it is so called inversion. By default, during the campaign it is measured size distribution of air born dust in range 5.6 nm −560nm by FMPS and using the sampler NanoId are collected samples in range 1nm – 35μm in 12 size fractions for chemical analysis and morphological observations. This contribution deals with results of size distributions only.

  20. Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters

    CERN Document Server

    Dash, Monika

    2013-01-01

    Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).

  1. Efficient nanoparticle mediated sustained RNA interference in human primary endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Mukerjee, Anindita; Shankardas, Jwalitha; Ranjan, Amalendu P; Vishwanatha, Jamboor K, E-mail: Jamboor.vishwanatha@unthsc.edu [Department of Molecular Biology and Immunology and Institute for Cancer Research, Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States)

    2011-11-04

    Endothelium forms an important target for drug and/or gene therapy since endothelial cells play critical roles in angiogenesis and vascular functions and are associated with various pathophysiological conditions. RNA mediated gene silencing presents a new therapeutic approach to overcome many such diseases, but the major challenge of such an approach is to ensure minimal toxicity and effective transfection efficiency of short hairpin RNA (shRNA) to primary endothelial cells. In the present study, we formulated shAnnexin A2 loaded poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles which produced intracellular small interfering RNA (siRNA) against Annexin A2 and brought about the downregulation of Annexin A2. The per cent encapsulation of the plasmid within the nanoparticle was found to be 57.65%. We compared our nanoparticle based transfections with Lipofectamine mediated transfection, and our studies show that nanoparticle based transfection efficiency is very high ({approx}97%) and is more sustained compared to conventional Lipofectamine mediated transfections in primary retinal microvascular endothelial cells and human cancer cell lines. Our findings also show that the shAnnexin A2 loaded PLGA nanoparticles had minimal toxicity with almost 95% of cells being viable 24 h post-transfection while Lipofectamine based transfections resulted in only 30% viable cells. Therefore, PLGA nanoparticle based transfection may be used for efficient siRNA transfection to human primary endothelial and cancer cells. This may serve as a potential adjuvant treatment option for diseases such as diabetic retinopathy, retinopathy of prematurity and age related macular degeneration besides various cancers.

  2. Efficient nanoparticle mediated sustained RNA interference in human primary endothelial cells

    Science.gov (United States)

    Mukerjee, Anindita; Shankardas, Jwalitha; Ranjan, Amalendu P.; Vishwanatha, Jamboor K.

    2011-11-01

    Endothelium forms an important target for drug and/or gene therapy since endothelial cells play critical roles in angiogenesis and vascular functions and are associated with various pathophysiological conditions. RNA mediated gene silencing presents a new therapeutic approach to overcome many such diseases, but the major challenge of such an approach is to ensure minimal toxicity and effective transfection efficiency of short hairpin RNA (shRNA) to primary endothelial cells. In the present study, we formulated shAnnexin A2 loaded poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles which produced intracellular small interfering RNA (siRNA) against Annexin A2 and brought about the downregulation of Annexin A2. The per cent encapsulation of the plasmid within the nanoparticle was found to be 57.65%. We compared our nanoparticle based transfections with Lipofectamine mediated transfection, and our studies show that nanoparticle based transfection efficiency is very high (~97%) and is more sustained compared to conventional Lipofectamine mediated transfections in primary retinal microvascular endothelial cells and human cancer cell lines. Our findings also show that the shAnnexin A2 loaded PLGA nanoparticles had minimal toxicity with almost 95% of cells being viable 24 h post-transfection while Lipofectamine based transfections resulted in only 30% viable cells. Therefore, PLGA nanoparticle based transfection may be used for efficient siRNA transfection to human primary endothelial and cancer cells. This may serve as a potential adjuvant treatment option for diseases such as diabetic retinopathy, retinopathy of prematurity and age related macular degeneration besides various cancers.

  3. Efficient nanoparticle mediated sustained RNA interference in human primary endothelial cells

    International Nuclear Information System (INIS)

    Mukerjee, Anindita; Shankardas, Jwalitha; Ranjan, Amalendu P; Vishwanatha, Jamboor K

    2011-01-01

    Endothelium forms an important target for drug and/or gene therapy since endothelial cells play critical roles in angiogenesis and vascular functions and are associated with various pathophysiological conditions. RNA mediated gene silencing presents a new therapeutic approach to overcome many such diseases, but the major challenge of such an approach is to ensure minimal toxicity and effective transfection efficiency of short hairpin RNA (shRNA) to primary endothelial cells. In the present study, we formulated shAnnexin A2 loaded poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles which produced intracellular small interfering RNA (siRNA) against Annexin A2 and brought about the downregulation of Annexin A2. The per cent encapsulation of the plasmid within the nanoparticle was found to be 57.65%. We compared our nanoparticle based transfections with Lipofectamine mediated transfection, and our studies show that nanoparticle based transfection efficiency is very high (∼97%) and is more sustained compared to conventional Lipofectamine mediated transfections in primary retinal microvascular endothelial cells and human cancer cell lines. Our findings also show that the shAnnexin A2 loaded PLGA nanoparticles had minimal toxicity with almost 95% of cells being viable 24 h post-transfection while Lipofectamine based transfections resulted in only 30% viable cells. Therefore, PLGA nanoparticle based transfection may be used for efficient siRNA transfection to human primary endothelial and cancer cells. This may serve as a potential adjuvant treatment option for diseases such as diabetic retinopathy, retinopathy of prematurity and age related macular degeneration besides various cancers.

  4. Animal magnetocardiography using superconducting quantum interference device gradiometers assisted with magnetic nanoparticle injection: A sensitive method for early detecting electromagnetic changes induced by hypercholesterolemia

    Science.gov (United States)

    Wu, C. C.; Hong, B. F.; Wu, B. H.; Yang, S. Y.; Horng, H. E.; Yang, H. C.; Tseng, W. Y. Isaac; Tseng, W. K.; Liu, Y. B.; Lin, L. C.; Lu, L. S.; Lee, Y. H.

    2007-01-01

    In this work, the authors used a superconducting quantum interference device (SQUID) magnetocardiography (MCG) system consisted of 64-channel low-transition-temperature SQUID gradiometers to detect the MCG signals of hepercholesterolemic rabbits. In addition, the MCG signals were recorded before and after the injection of magnetic nanoparticles into the rabbits' ear veins to investigate the effects of magnetic nanoparticles on the MCG signals. These MCG data were compared to those of normal rabbits to reveal the feasibility for early detection of the electromagnetic changes induced by hypercholesterolemia using MCG with the assistance of magnetic nanoparticle injection.

  5. Polyelectrolyte coatings prevent interferences from charged nanoparticles in SPME speciation analysis

    International Nuclear Information System (INIS)

    Zielińska, Katarzyna; Leeuwen, Herman P. van

    2014-01-01

    Highlights: • For the first time SPME fiber is coated with polyelectrolyte layer. • Sorption of nanoparticles on the solid phase surface is prevented. • Polyelectrolyte-modified fiber enables extraction of free analyte in presence of sorbing nanoparticles. - Abstract: In this work we present a new approach for protection of the fiber in solid phase microextraction (SPME) from interfering charged particles present in the sample medium. It involves coating of commercial poly(dimethylsiloxane) extraction phase with polyelectrolyte layer composed of poly(diallyldimethylammonium chloride), and poly(sodium 4-styrenesulfonate). The modified fiber provides reproducible, convenient and fast extraction capabilities toward the model analyte, triclosan (TCS). A negatively charged polyelectrolyte coating prevents sorbing oxidic nanoparticles from both partitioning into the PDMS phase and aggregation at its surface. The results for the TCS/nanoparticle sample show that the polyelectrolyte layer-modified solid phase extracts just the free form of the organic compound and enables dynamic speciation analysis of the nanoparticulate target analyte complex

  6. Does surface coating of metallic nanoparticles modulate their interference with in vitro assays?

    Czech Academy of Sciences Publication Activity Database

    Vinković Vrček, I.; Pavičić, I.; Crnković, T.; Jurašin, D.; Babič, Michal; Horák, Daniel; Lovrić, M.; Ferhatović, L.; Ćurlin, M.; Gajović, S.

    2015-01-01

    Roč. 5, č. 87 (2015), s. 70787-70807 ISSN 2046-2069 EU Projects: European Commission(XE) 316120 - GLOWBRAIN Institutional support: RVO:61389013 Keywords : nanoparticle * biomedicine Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.289, year: 2015

  7. Silica nanoparticles capture atmospheric lead: implications in the treatment of environmental heavy metal pollution.

    Science.gov (United States)

    Yang, Xifei; Shen, Zhiguo; Zhang, Bing; Yang, Jianping; Hong, Wen-Xu; Zhuang, Zhixiong; Liu, Jianjun

    2013-01-01

    Lead (Pb) contamination in the air is a severe global problem, most notably in China. Removal of Pb from polluted air remains a significant challenge. It is unclear what potential effects silica nanoparticles (SiNPs) exposure can have on atmospheric Pb. Here we first characterized the features of SiNPs by measuring the particle size, zeta potential and the specific surface area of SiO(2) particles using a Nicomp 380/ZLS submicron particle sizer, the Brunauer-Emmett-Teller (BET) method and transmission electronic microscopy (TEM). We measured the content of the metal Pb adsorbed by SiNPs exposed to two Pb polluted electric battery plants using inductively coupled plasma mass spectrometry (ICP-MS). It is found that SiNPs exposed to two Pb polluted electric battery plants absorb more atmospheric Pb compared to either blank control or micro-sized SiO(2) particles in a time-dependent manner. This is the first study demonstrating that SiNPs exposure can absorb atmospheric Pb in the polluted environment. These novel findings indicate that SiNPs have potential to serve as a significant adsorbent of Pb from industrial pollution, implicating a potentially novel application of SiNPs in the treatment of environmental heavy metal pollution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Functionalized magnetic nanoparticles for the decontamination of water polluted with cesium

    Directory of Open Access Journals (Sweden)

    Ahmed S. Helal

    2016-05-01

    Full Text Available Magnetic nanoparticles are attracting considerable interest because of their potential applications in practically all fields of science and technology, including the removal of heavy metals from contaminated waters. It is, therefore, of great importance to adapt the surfaces of these nanoparticles according to the application. In this work advanced nanoparticles (NPs with well-tailored surface functionalities were synthesized using the polyol method. The efficiency of a chelating agent, succinyl-β-cyclodextrin (SBCD, was first investigated spectrophotometrically and by Isothermal Titration Calorimetry (ITC. SBCD was then grafted onto nanoparticles previously functionalized with 3-aminopropyl triethoxsilane (NP-APTES. The resulting NP-SBCD system was then incubated with a solution of cesium. After magnetic separation, the solid residue was removed from the supernatant and characterized by X-Ray Photoelectron spectrometry (XPS, X-Ray Fluorescence spectrometry (XRF and Superconducting QUantum Interference Device (SQUID magnetometry. These characterizations show the presence of cesium in the solid residue, which indicates Cs uptake by the NP-SBCD system. This nanohybrid system constitutes a promising model for heavy metal decontamination.

  9. Mussel-inspired polydopamine biopolymer decorated with magnetic nanoparticles for multiple pollutants removal

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shengxiao, E-mail: beijingzsx@163.com [School of Chemistry and Materials Science, Ludong University, Yantai 264025, Shandong Province (China); Zhang, Yuanyuan [School of Chemistry and Materials Science, Ludong University, Yantai 264025, Shandong Province (China); Bi, Guoming [Yantai Enironmental Monitoring Center, Yantai 264025, Shandong Province (China); Liu, Junshen [School of Chemistry and Materials Science, Ludong University, Yantai 264025, Shandong Province (China); Wang, Zhigang [Yantai Enironmental Monitoring Center, Yantai 264025, Shandong Province (China); Xu, Qiang; Xu, Hui; Li, Xiaoyan [School of Chemistry and Materials Science, Ludong University, Yantai 264025, Shandong Province (China)

    2014-04-01

    Highlights: • The Fe{sub 3}O{sub 4}/PDA hybrid material was synthesized and characterized. • The PDA polymer was firstly applied in environmental remediation. • The Fe{sub 3}O{sub 4}/PDA exhibited high adsorption capacity for multiple pollutants. • Removal efficiencies of pollutants with Fe{sub 3}O{sub 4}/PDA were pH dependent. - Abstract: The polydopamine polymer decorated with magnetic nanoparticles (Fe{sub 3}O{sub 4}/PDA) was synthesized and applied for removal of multiple pollutants. The resulted Fe{sub 3}O{sub 4}/PDA was characterized with elemental analysis, thermo-gravimetric analyses, vibrating sample magnetometer, high resolution transmission electron microscope, Fourier transform infrared spectra, and X-ray photoelectron spectroscopy. The self-polymerization of dopamine could be completed within 8 h, and Fe{sub 3}O{sub 4} nanoparticles were embedded into PDA polymer. Superparamagnetism and large saturation magnetization facilitated collection of sorbents with a magnet. Based on the catechol and amine groups, the PDA polymer provided multiple interactions to combine with pollutants. To investigate the adsorption ability of Fe{sub 3}O{sub 4}/PDA, heavy metal ions and dyes were selected as target pollutants. The adsorption of pollutants was pH dependent due to the variation of surface charges at different solution pH. The removal efficiencies of cation pollutants enhanced with solution pH increasing, and that of anion pollutant was just the opposite. Under the optimal solution pH, the maximum adsorption capacity calculated from Langmuir adsorption isotherm for methylene blue, tartrazine, Cu{sup 2+}, Ag{sup +}, and Hg{sup 2+} were 204.1, 100.0, 112.9, 259.1, and 467.3 mg g{sup −1}, respectively. The Fe{sub 3}O{sub 4}/PDA shows great potential for multiple pollutants removal, and this study is the first application of PDA polymer in environmental remediation.

  10. Titanate nanotubes sensitized with silver nanoparticles: Synthesis, characterization and in-situ pollutants photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Barrocas, B.; Nunes, C.D. [Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Carvalho, M.L. [LIBPhys-UNL, Laboratório de Instrumentação, Engenharia Biomédica e Física da Radiação and Departamento de Física da Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Monteiro, O.C., E-mail: ocmonteiro@ciencias.ulisboa.pt [Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa (Portugal)

    2016-11-01

    Highlights: • Combination of titanate nanotubes with crystalline silver nanoparticles is described. • AgHTNT demonstrated high photocatalytic activity for hydroxyl radical production. • AgHTNT exhibits the best photocatalytic activity for phenol removal. • Recycling does not affect AgHTNT photocatalytic performance. • Silver nanoparticles growth continues during several irradiation cycles. - Abstract: In this work, titanate nanotubes were modified with silver nanoparticles to produce new nanocomposite materials with enhanced photocatalytic activity for phenol removal. The TNTs were produced using a hydrothermal approach and, after being submitted to an Ag{sup +} exchange process, metallic Ag nanoparticles were obtained over the nanotubes surface. The prepared materials were structural, morphological and optical characterized by X-ray powder diffraction, micro X-ray fluorescence, transmission electron microscopy, diffused reflectance spectroscopy and X-ray photoelectron spectroscopy. The characterization results indicate that Ag{sup +} was immobilized not only in the nanotubes external surface but mainly in the TiO{sub 6} interlayers space. The application of this new nanocomposite material on photocatalytic degradation of pollutants was investigated. First, the evaluation of hydroxyl radical formation, using the terephthalic acid as a probe was studied. The photocatalytic activity of the sensitized materials for phenol degradation was afterwards evaluated. The results show that the nanocomposite sample is the best catalyst, achieving 98.0% photodegradation efficiency of a 0.2 mM phenol solution within 20 min under UV–vis radiation. The reusability of the prepared samples as photocatalysts was evaluated in four successive degradation assays, using fresh phenol solutions. The sensitized sample demonstrated excellent catalytic reusability ability, without loss of photochemical stability. The structural and morphological characterization during these

  11. Interference-Free Electrochemical Detection of Nanomolar Dopamine Using Doped Polypyrrole and Silver Nanoparticles

    OpenAIRE

    Saha, Suparna; Sarkar, Priyabrata; Turner, Anthony

    2014-01-01

    This paper presents a new approach to detect dopamine in nanomolar range using an electrochemical sensor utilizing a composite made of chitosan-stabilized silver nanoparticles and p-toluene sulfonic acid-doped ultrathin polypyrrole film. Studies included cyclic voltammogram, amperometry, differential pulse voltammetry and also investigation by electrochemical impedance spectroscopy. A detection limit of 0.58 nM was achieved in the linear range 1 x 10(-9) M to 1.2 x 10(-7) M. High sensitivity ...

  12. Electrosynthesis and characterization of gold nanoparticles for electronic capacitance sensing of pollutants

    International Nuclear Information System (INIS)

    Cioffi, Nicola; Colaianni, Lorenzo; Ieva, Eliana; Pilolli, Rosa; Ditaranto, Nicoletta; Angione, Maria Daniela; Cotrone, Serafina; Buchholt, Kristina; Spetz, Anita Lloyd; Sabbatini, Luigia; Torsi, Luisa

    2011-01-01

    In the present study, gold/surfactant core/shell colloidal nanoparticles with a controlled morphology and chemical composition have been obtained via the so-called sacrificial anode technique, carried out in galvanostatic mode. As synthesized Au-NPs had an average core diameter comprised between 4 and 8 nm, as a function of the electrochemical process experimental conditions. The UV-Vis characterization of gold nanocolloids showed clear spectroscopic size effects, affecting both the position and width of the nanoparticle surface plasmon resonance peak. The nanomaterial surface spectroscopic characterization showed the presence of two chemical states, namely nanostructured Au(0) (its abundance being higher than 90%) and Au(I). Au-NPs were then deposited on the top of a capacitive field effect sensor and subjected to a mild thermal annealing aiming at removing the excess of stabilizing surfactant molecules. Au-NP sensors were tested towards some gases found in automotive gas exhausts. The sensing device showed the largest response towards NO x , and much smaller - if any - responses towards interferent species such as NH 3 , H 2 , CO, and hydrocarbons.

  13. Lightweight reduced graphene oxide-Fe3O4 nanoparticle composite in the quest for an excellent electromagnetic interference shielding material

    Science.gov (United States)

    Singh, Ashwani Kumar; Kumar, Ajit; Kamal Haldar, Krishna; Gupta, Vinay; Singh, Kedar

    2018-06-01

    This work reports a detailed study of reduced graphene oxide (rGO)-Fe3O4 nanoparticle composite as an excellent electromagnetic (EM) interference shielding material in GHz range. A rGO-Fe3O4 nanoparticle composite was synthesized using a facile, one step, and modified solvothermal method with the reaction of FeCl3, ethylenediamine and graphite oxide powder in the presence of ethylene glycol. Various structural, microstructural and optical characterization tools were used to determine its synthesis and various properties. Dielectric, magnetic and EM shielding parameters were also evaluated to estimate its performance as a shielding material for EM waves. X-ray diffraction patterns have provided information about the structural and crystallographic properties of the as-synthesized material. Scanning electron microscopy micrographs revealed the information regarding the exfoliation of graphite into rGO. Well-dispersed Fe3O4 nanoparticles over the surface of the graphene can easily be seen by employing transmission electron microscopy. For comparison, rGO nanosheets and Fe3O4 nanoparticles have also been synthesized and characterized in a similar fashion. A plot of the dielectric and magnetic characterizations provides some useful information related to various losses and the relaxation process. Shielding effectiveness due to reflection (SER), shielding effectiveness due to absorption (SEA), and total shielding effectiveness (SET) were also plotted against frequency over a broad range (8–12 GHz). A significant change in all parameters (SEA value from 5 dB to 35 dB for Fe3O4 nanoparticles to rGO-Fe3O4 nanoparticle composite) was found. An actual shielding effectiveness (SET) up to 55 dB was found in the rGO-Fe3O4 nanoparticle composite. These graphs give glimpses of how significantly this material shows shielding effectiveness over a broad range of frequency.

  14. Lightweight reduced graphene oxide-Fe3O4 nanoparticle composite in the quest for an excellent electromagnetic interference shielding material.

    Science.gov (United States)

    Singh, Ashwani Kumar; Kumar, Ajit; Haldar, Krishna Kamal; Gupta, Vinay; Singh, Kedar

    2018-06-15

    This work reports a detailed study of reduced graphene oxide (rGO)-Fe 3 O 4 nanoparticle composite as an excellent electromagnetic (EM) interference shielding material in GHz range. A rGO-Fe 3 O 4 nanoparticle composite was synthesized using a facile, one step, and modified solvothermal method with the reaction of FeCl 3 , ethylenediamine and graphite oxide powder in the presence of ethylene glycol. Various structural, microstructural and optical characterization tools were used to determine its synthesis and various properties. Dielectric, magnetic and EM shielding parameters were also evaluated to estimate its performance as a shielding material for EM waves. X-ray diffraction patterns have provided information about the structural and crystallographic properties of the as-synthesized material. Scanning electron microscopy micrographs revealed the information regarding the exfoliation of graphite into rGO. Well-dispersed Fe 3 O 4 nanoparticles over the surface of the graphene can easily be seen by employing transmission electron microscopy. For comparison, rGO nanosheets and Fe 3 O 4 nanoparticles have also been synthesized and characterized in a similar fashion. A plot of the dielectric and magnetic characterizations provides some useful information related to various losses and the relaxation process. Shielding effectiveness due to reflection (SE R ), shielding effectiveness due to absorption (SE A ), and total shielding effectiveness (SE T ) were also plotted against frequency over a broad range (8-12 GHz). A significant change in all parameters (SE A value from 5 dB to 35 dB for Fe 3 O 4 nanoparticles to rGO-Fe 3 O 4 nanoparticle composite) was found. An actual shielding effectiveness (SE T ) up to 55 dB was found in the rGO-Fe 3 O 4 nanoparticle composite. These graphs give glimpses of how significantly this material shows shielding effectiveness over a broad range of frequency.

  15. Pollution

    NARCIS (Netherlands)

    Dürr, E.; Jaffe, R.; Nonini, D.M.

    2014-01-01

    This essay points to the role of pollution in understanding the social construction of hierarchies and urban space. Conceptualizations of pollution and approaches to waste management always reflect the Zeitgeist and tend to be politically charged. We argue that an ethnographic approach to pollution

  16. Biosynthesis of gold nanoparticles by Aspergillum sp. WL-Au for degradation of aromatic pollutants

    Science.gov (United States)

    Qu, Yuanyuan; Pei, Xiaofang; Shen, Wenli; Zhang, Xuwang; Wang, Jingwei; Zhang, Zhaojing; Li, Shuzhen; You, Shengnan; Ma, Fang; Zhou, Jiti

    2017-04-01

    A simple method for synthesis of gold nanoparticles (AuNPs) using Aspergillum sp. WL-Au was presented in this study. According to UV-vis spectra and transmission electron microscopy images, the shape and size of AuNPs were affected by different parameters, including buffer solution, pH, biomass and HAuCl4 concentrations. Phosphate sodium buffer was more suitable for extracellular synthesis of AuNPs, and the optimal conditions for AuNPs synthesis were pH 7.0, biomass 100 mg/mL and HAuCl4 3 mM, leading to the production of spherical and pseudo-spherical nanoparticles. The biosynthesized AuNPs possessed excellent catalytic activities for the reduction of 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, o-nitroaniline and m-nitroaniline in the presence of NaBH4, and the catalytic rate constants were calculated to be 6.3×10-3 s-1, 5.5×10-3 s-1, 10.6×10-3 s-1, 8.4×10-3 s-1 and 13.8×10-3 s-1, respectively. The AuNPs were also able to catalyze the decolorization of various azo dyes (e.g. Cationic Red X-GRL, Acid Orange II and Acid scarlet GR) using NaBH4 as the reductant, and the decolorization rates reached 91.0-96.4% within 7 min. The present study should provide a potential candidate for green synthesis of AuNPs, which could serve as efficient catalysts for aromatic pollutants degradation.

  17. Mechanically Robust Magnetic Carbon Nanotube Papers Prepared with CoFe2O4 Nanoparticles for Electromagnetic Interference Shielding and Magnetomechanical Actuation.

    Science.gov (United States)

    Lim, Guh-Hwan; Woo, Seongwon; Lee, Hoyoung; Moon, Kyoung-Seok; Sohn, Hiesang; Lee, Sang-Eui; Lim, Byungkwon

    2017-11-22

    The introduction of inorganic nanoparticles into carbon nanotube (CNT) papers can provide a versatile route to the fabrication of CNT papers with diverse functionalities, but it may lead to a reduction in their mechanical properties. Here, we describe a simple and effective strategy for the fabrication of mechanically robust magnetic CNT papers for electromagnetic interference (EMI) shielding and magnetomechanical actuation applications. The magnetic CNT papers were produced by vacuum filtration of an aqueous suspension of CNTs, CoFe 2 O 4 nanoparticles, and poly(vinyl alcohol) (PVA). PVA plays a critical role in enhancing the mechanical strength of CNT papers. The magnetic CNT papers containing 73 wt % of CoFe 2 O 4 nanoparticles exhibited high mechanical properties with Young's modulus of 3.2 GPa and tensile strength of 30.0 MPa. This magnetic CNT paper was successfully demonstrated as EMI shielding paper with shielding effectiveness of ∼30 dB (99.9%) in 0.5-1.0 GHz, and also as a magnetomechanical actuator in an audible frequency range from 200 to 20 000 Hz.

  18. AC conductivity, magnetic and shielding effectiveness studies on polyaniline embedded Co0.5Mn0.5Fe2O4 nanoparticles for electromagnetic interference suppression

    Science.gov (United States)

    Gurusiddesh, M.; Madhu, B. J.; Shankaramurthy, G. J.

    2018-05-01

    Electrically conducting Polyaniline (PANI)/Co0.5Mn0.5Fe2O4 nanocomposites are synthesized by in situ polymerization of aniline monomer in the presence of Co0.5Mn0.5Fe2O4 nanoparticles. Structural studies on the synthesized samples have been carried out using X-ray diffraction technique, Field emission scanning electron microscopy and Energy dispersive X-ray spectroscopy. Frequency dependent ac conductivity studies on the prepared samples revealed that conductivity of the composite is high compared to Co0.5Mn0.5Fe2O4 nanoparticles. Further, both the samples exhibited hysteresis behavior under the applied magnetic field. Electromagnetic interference (EMI) shielding effectiveness of both the samples decreases with increase in the applied frequency in the studied frequency range. Maximum shielding effectiveness (SE) of 31.49 dB and 62.84 dB were obtained for Co0.5Mn0.5Fe2O4 nanoparticles and PANI/Co0.5Mn0.5Fe2O4 nanocomposites respectively in the studied frequency range. Observed higher EMI shielding in the composites was attributed to its high electrical conductivity.

  19. Comparison of the Efficiencies of Zero-Valent Iron Nanoparticles and Stabilized Iron Nanoparticles for Nitrate Reduction from Polluted Waters

    Directory of Open Access Journals (Sweden)

    Fatemeh Nooralivand

    2015-12-01

    Full Text Available The present study was conducted to evaluate the feasibility of zero-valent iron nanoparticles (ZVIN for the removal of nitrate from aqueous solutions. For this purpose, bare zero-valent iron nanoparticles (bare-ZVIN and CMC-ZVIN were synthesized using the borohydride reduction method and their morphological characteristics were examined via scanning electron microscopy (SEM, X-ray diffraction (XRD, and Fourier Transmission Infrared Spectroscopy (FTIR. The effects of pH of the aqueous solution, initial nitrate concentration, ZVIN concentration, and contact time on nitrate reduction were investigated as operational parameters and the kinetics of nitrate reduction was studied in batch experiments. The results showed that 93.65% of nitrate was removed by stabilized nanoparticles at pH=6 while non-stabilized nanoparticles at pH=2 were able to remove 85.55% of the nitrate.Furthermore, nitrate reduction was enhanced by increasing ZVIN concentration and contact time while it was decreased as a result of increasing initial nitrate concentration. The major product of nitrate reduction at an acidic pH was found to be ammonium; at an alkaline pH, however, nitrate was converted to nitrogen and nitrite production dropped to less than 2%. Kinetic analysis demonstrated that denitrification of nitrate by the nanoparticles fitted well with first-order and second-order reaction models. The results also demonstrated that the stabilized ZVI nanoparticles were more effective than bare-ZVIN for nitrate reduction in aqueous solutions.

  20. Controlling the electrochemical deposition of silver onto gold nanoparticles: reducing interferences and increasing the sensitivity of magnetoimmuno assays.

    Science.gov (United States)

    de la Escosura-Muñiz, Alfredo; Maltez-da Costa, Marisa; Merkoçi, Arben

    2009-04-15

    An electrocatalytical method induced by gold nanoparticles in order to improve the sensitivity of the magnetoimmunosensing technology is reported. Microparamagnetic beads as primary antibodies immobilization platforms and gold nanoparticles modified with secondary antibodies as high sensitive electrocatalytical labels are used. A built-in magnet carbon electrode allows the collection/immobilization on its surface of the microparamagnetic beads with the immunological sandwich and gold nanoparticle catalysts attached onto. The developed magnetoimmunosensing technology allows the antigen detection with an enhanced sensitivity due to the catalytic effect of gold nanoparticles on the electroreduction of silver ions. The main parameters that affect the different steps of the developed assay are optimized so as to reach a high sensitive electrochemical detection of the protein. The low levels of gold nanoparticles detected with this method allow the obtaining of a novel immunosensor with low protein detection limits (up to 23 fg/mL), with special interest for further applications in clinical analysis, food quality and safety as well as other industrial applications.

  1. Green synthesis of gold nanoparticles for trace level detection of a hazardous pollutant (nitrobenzene) causing Methemoglobinaemia

    Energy Technology Data Exchange (ETDEWEB)

    Emmanuel, R. [Post Graduate and Research Department of Chemistry, Thiagarajar College, Madurai 625009, Tamil Nadu (India); Karuppiah, Chelladurai [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 106, Taiwan, ROC (China); Chen, Shen-Ming, E-mail: smchen78@ms15.hinet.net [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 106, Taiwan, ROC (China); Palanisamy, Selvakumar [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei 106, Taiwan, ROC (China); Padmavathy, S. [Department of Zoology and Microbiology, Thiagarajar College, Madurai 625009, Tamil Nadu (India); Prakash, P., E-mail: kmpprakash@gmail.com [Post Graduate and Research Department of Chemistry, Thiagarajar College, Madurai 625009, Tamil Nadu (India)

    2014-08-30

    Graphical abstract: Schematic representation for green synthesis of Au-NPs and its electroreduction of nitrobenzene. - Highlights: • A green synthesis of size controlled Au-NPs from plant extract. • Trace level detection of nitro benzene, a pollutant causing Methemoglobinaemia, at Au-NPs modified electrode. • Achievement of lower LOD and wider linear response. • The proposed sensor exhibits excellent practicality in various water samples. - Abstract: The present study involves a green synthesis of gold nanoparticles (Au-NPs) using Acacia nilotica twig bark extract at room temperature and trace level detection of one of the hazardous materials, viz. nitrobenzene (NB) that causes Methemoglobinaemia. The synthesis protocol demonstrates that the bioreduction of chloroauric acid leads to the formation of Au-NPs within 10 min, suggesting a higher reaction rate than any other chemical methods involved. The obtained Au-NPs have been characterized by UV–vis spectroscopy, X-ray diffraction, transmission electron microscopy, Energy-Dispersive X-ray Spectroscopy and Fourier Transform Infrared Spectroscopy. The electrochemical detection of NB has been investigated at the green synthesized Au-NPs modified glassy carbon electrode by using differential pulse voltammetry (DPV). The Au-NPs modified electrode exhibits excellent reduction ability toward NB compared to unmodified electrode. The developed NB sensor at Au-NPs modified electrode displays a wide linear response from 0.1 to 600 μM with high sensitivity of 1.01 μA μM{sup −1} cm{sup −2} and low limit of detection of 0.016 μM. The modified electrode shows exceptional selectivity in the presence of ions, phenolic and biologically coactive compounds. In addition, the Au-NPs modified electrode exhibits an outstanding recovery results toward NB in various real water samples.

  2. Green synthesis of gold nanoparticles for trace level detection of a hazardous pollutant (nitrobenzene) causing Methemoglobinaemia

    International Nuclear Information System (INIS)

    Emmanuel, R.; Karuppiah, Chelladurai; Chen, Shen-Ming; Palanisamy, Selvakumar; Padmavathy, S.; Prakash, P.

    2014-01-01

    Graphical abstract: Schematic representation for green synthesis of Au-NPs and its electroreduction of nitrobenzene. - Highlights: • A green synthesis of size controlled Au-NPs from plant extract. • Trace level detection of nitro benzene, a pollutant causing Methemoglobinaemia, at Au-NPs modified electrode. • Achievement of lower LOD and wider linear response. • The proposed sensor exhibits excellent practicality in various water samples. - Abstract: The present study involves a green synthesis of gold nanoparticles (Au-NPs) using Acacia nilotica twig bark extract at room temperature and trace level detection of one of the hazardous materials, viz. nitrobenzene (NB) that causes Methemoglobinaemia. The synthesis protocol demonstrates that the bioreduction of chloroauric acid leads to the formation of Au-NPs within 10 min, suggesting a higher reaction rate than any other chemical methods involved. The obtained Au-NPs have been characterized by UV–vis spectroscopy, X-ray diffraction, transmission electron microscopy, Energy-Dispersive X-ray Spectroscopy and Fourier Transform Infrared Spectroscopy. The electrochemical detection of NB has been investigated at the green synthesized Au-NPs modified glassy carbon electrode by using differential pulse voltammetry (DPV). The Au-NPs modified electrode exhibits excellent reduction ability toward NB compared to unmodified electrode. The developed NB sensor at Au-NPs modified electrode displays a wide linear response from 0.1 to 600 μM with high sensitivity of 1.01 μA μM −1 cm −2 and low limit of detection of 0.016 μM. The modified electrode shows exceptional selectivity in the presence of ions, phenolic and biologically coactive compounds. In addition, the Au-NPs modified electrode exhibits an outstanding recovery results toward NB in various real water samples

  3. Non-invasive and high-sensitivity scanning detection of magnetic nanoparticles in animals using high-Tc scanning superconducting-quantum-interference-device biosusceptometry.

    Science.gov (United States)

    Chieh, J J; Hong, C Y

    2011-08-01

    Although magnetic nanoparticles (MNPs) have been widely applied to animals in biomedicine, MNPs within animals should be examined in real time, in vivo, and without bio-damaged possibility to evaluate whether the bio-function of MNPs is valid or to further controls the biomedicinal process because of accompanying complex problems such as MNPs distribution and MNPs biodegradation. The non-invasive and high-sensitivity scanning detection of MNPs in animals using ac susceptometry based on a high-T(c) superconducting quantum interference device (SQUID) is presented. The non-invasive results and biopsy results show good agreement, and two gold-standard biomedicine methods, Prussian blue stain and inductively coupled plasma, prove the magnetic results. This confirms that the future clinical diagnosis of bio-functional MNPs could be operated by using scanning SQUID biosusceptometry as conveniently as an ultrasonic probe.

  4. Removal of acidic interferences in multi-pesticides residue analysis of fruits using modified magnetic nanoparticles prior to determination via ultra-HPLC-MS/MS

    International Nuclear Information System (INIS)

    Qi, Peipei; Wang, Zhiwei; Yang, Guiling; Wang, Xinquan; Shang, Chunqing; Xu, Hao; Wang, Xiangyun; Zhang, Hu; Wang, Qiang

    2015-01-01

    The authors describe magnetite (Fe 3 O 4 ) nanoparticles modified with 3-(N,N-diethylamino) propyltrimethoxysilane (Fe 3 O 4 -PSA NPs) for use as a sorbent for dispersive solid phase extraction of pesticide residues. The Fe 3 O 4 -PSA NPs were prepared by silanizing Fe 3 O 4 NPs and modifying them with 3-(N,N-diethylamino) propyltrimethoxysilane. Field-emission scanning electron microscopy, FTIR and zeta potential measurements were employed to characterize the modified NPs. They were then used as an adsorbent to remove acidic interferences (such as malic acid and succinic acid), which are major interferences in LC-MS/MS analysis in causing ion suppression in the MS spectra of pesticides. In addition, graphitized carbon black (GCB) was used as an adsorbent to eliminate interferences by pigments. The use of Fe 3 O 4 -PSA NPs can replace time-consuming centrifugation as used in the so-called QuEChERS (quick, easy, cheap, effective, rugged and safe) method. This improvement is particularly significant in high-throughput analysis. Following the optimization of the quantities of Fe 3 O 4 -PSA NPs and GCB, the method was applied to the determination of 56 pesticides in (spiked) fruits (apple, kiwi, orange and pear) by ultra-HPLC-MS/MS. The analytical ranges typically extend from 1 to 200 ng∙mL −1 , and recoveries range from 60.2 to 130 % at different concentrations of all four kinds of fruits. The LOQs for the pesticides are 10 ng∙kg −1 , which makes the method a viable tool for pesticide monitoring in fruits. (author)

  5. Multi-pollutant interactions in hyporheic zones

    Science.gov (United States)

    Krause, S.; Weatherill, J.; Bonet, B.; Blaen, P.; Khamis, K.; Cassidy, N. J.; Hannah, D. M.; Rivett, M. O.; Lynch, I.; Ullah, S.

    2017-12-01

    Hyporheic zones represent hotspots of biogeochemical reactivity, with the potential to attenuate pollutants and ameliorate their impact on ecosystem functioning. Sources and types of pollutants in streambed environments are manifold, with legacy industry contaminants, agricultural pollution and emerging pollutants such as pharmaceuticals or engineered nanoparticles entering hyporheic zones along different flow paths where they mix and potentially react with each other. Current conceptualizations of drivers and controls of biogeochemical turnover in hyporheic zones highlight primarily the role of transport and reaction times but do not account for potential interactions between different pollutants. This study presents two case studies of multi-pollutant interactions to illustrate the need to consider interferences between different pollutants, their transport and reaction pathways for adequate impact assessment. We discuss in the first instance how the natural attenuation of a Trichloroethylene (TCE) groundwater plume in an agricultural catchment is limited by high riparian and hyporheic nitrate concentrations. As nitrate outcompeted TCE in its reaction with organic carbon as electron donor, TCE attenuation was in this case limited to hyporheic denitrification hotspots. Hence any pollution control measures to reduce the impact of this TCE plume require a reduction of agricultural nitrate loads, highlighting the connectedness of legacy (TCE) and more recent (nitrate) pollution problems. In the second case, we investigate how the labile organic carbon content of streambed sediments as main control of hyporheic respiration is overridden by exposure to different silver nanoparticle concentrations, representing emerging pollutants in many of our rivers. Also in this case, the impacts of different stressors (nanoparticle exposure) and drivers (availability of organic matter, water temperature) are interacting in their impacts on hyporheic zone functioning. We argue that

  6. Monitoring of oil pollution at Gemsa Bay and bioremediation capacity of bacterial isolates with biosurfactants and nanoparticles.

    Science.gov (United States)

    El-Sheshtawy, H S; Khalil, N M; Ahmed, W; Abdallah, R I

    2014-10-15

    Fifteen crude oil-degrading bacterial isolates were isolated from an oil-polluted area in Gemsa Bay, Red Sea, Egypt. Two bacterial species showed the highest growth rate on crude oil hydrocarbons. From an analysis of 16S rRNA sequences, these isolates were identified as Pseudomonas xanthomarina KMM 1447 and Pseudomonas stutzeri ATCC 17588. Gas Chromatographic (GC) analysis of the crude oil remaining in the culture medium after one week at 30°C showed that the optimum biodegradation of crude petroleum oil was demonstrated at 50% in medium containing biosurfactant with two types of nanoparticles separately and two bacterial species. The complete degradation of some different members of polyaromatics and the percentage biodegradation of other polyaromatics increased in microcosm containing two different types of nanoparticles with biosurfactant after 7 days. In conclusion, these bacterial strains may be useful for the bioremediation process in the Gemsa Bay, Red Sea decreasing oil pollution in this marine ecosystem. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Microwave assisted polymer stabilized synthesis of silver nanoparticles and its application in the degradation of environmental pollutants

    International Nuclear Information System (INIS)

    Rastogi, Pankaj Kumar; Ganesan, Vellaichamy; Krishnamoorthi, S.

    2012-01-01

    Highlights: ► Graft copolymers of polyacrylamide and dextran are synthesized by grafting PAM chains onto a Dx backbone. ► Silver nanoparticles dispersed copolymer nano-composite (Ag-HDx-g-PAM) is synthesized by microwave heating. ► The environmentally benign and biodegradable copolymer, HDx-g-PAM acts as stabilizing and reducing agent. ► Ag-HDx-g-PAM nano-composite shows efficient catalytic activity for the reduction of environmental pollutants. - Abstract: Graft copolymers of polyacrylamide (PAM) and dextran (Dx) are synthesized by grafting PAM chains onto a Dx backbone (Dx-g-PAM) with ceric ion induced solution polymerization technique. Partial hydrolysis of Dx-g-PAM is carried out with sodium hydroxide solution to obtain HDx-g-PAM. To synthesize silver nanoparticles dispersed copolymer nano-composite (Ag-HDx-g-PAM), reduction of silver ions with HDx-g-PAM is carried out using microwave heating. The environmentally benign and biodegradable copolymer, HDx-g-PAM acts as both stabilizer and reducing agent. The copolymer nano-composite, Ag-HDx-g-PAM is characterized by FT-IR, transmission electron microscopy, scanning electron microscopy and optical spectroscopy. Further, the catalytic activity of Ag-HDx-g-PAM nano-composite towards the reduction of environmental pollutants like phenosafranine dye and aromatic nitro compounds are studied.

  8. Microwave assisted polymer stabilized synthesis of silver nanoparticles and its application in the degradation of environmental pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Rastogi, Pankaj Kumar [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, UP (India); Ganesan, Vellaichamy, E-mail: velganesh@yahoo.com [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, UP (India); Krishnamoorthi, S., E-mail: dr.skmoorthi@gmail.com [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005, UP (India)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer Graft copolymers of polyacrylamide and dextran are synthesized by grafting PAM chains onto a Dx backbone. Black-Right-Pointing-Pointer Silver nanoparticles dispersed copolymer nano-composite (Ag-HDx-g-PAM) is synthesized by microwave heating. Black-Right-Pointing-Pointer The environmentally benign and biodegradable copolymer, HDx-g-PAM acts as stabilizing and reducing agent. Black-Right-Pointing-Pointer Ag-HDx-g-PAM nano-composite shows efficient catalytic activity for the reduction of environmental pollutants. - Abstract: Graft copolymers of polyacrylamide (PAM) and dextran (Dx) are synthesized by grafting PAM chains onto a Dx backbone (Dx-g-PAM) with ceric ion induced solution polymerization technique. Partial hydrolysis of Dx-g-PAM is carried out with sodium hydroxide solution to obtain HDx-g-PAM. To synthesize silver nanoparticles dispersed copolymer nano-composite (Ag-HDx-g-PAM), reduction of silver ions with HDx-g-PAM is carried out using microwave heating. The environmentally benign and biodegradable copolymer, HDx-g-PAM acts as both stabilizer and reducing agent. The copolymer nano-composite, Ag-HDx-g-PAM is characterized by FT-IR, transmission electron microscopy, scanning electron microscopy and optical spectroscopy. Further, the catalytic activity of Ag-HDx-g-PAM nano-composite towards the reduction of environmental pollutants like phenosafranine dye and aromatic nitro compounds are studied.

  9. Can visible light impact litter decomposition under pollution of ZnO nanoparticles?

    Science.gov (United States)

    Du, Jingjing; Zhang, Yuyan; Liu, Lina; Qv, Mingxiang; Lv, Yanna; Yin, Yifei; Zhou, Yinfei; Cui, Minghui; Zhu, Yanfeng; Zhang, Hongzhong

    2017-11-01

    ZnO nanoparticles is one of the most used materials in a wide range including antibacterial coating, electronic device, and personal care products. With the development of nanotechnology, ecotoxicology of ZnO nanoparticles has been received increasing attention. To assess the phototoxicity of ZnO nanoparticles in aquatic ecosystem, microcosm experiments were conducted on Populus nigra L. leaf litter decomposition under combined effect of ZnO nanoparticles and visible light radiation. Litter decomposition rate, pH value, extracellular enzyme activity, as well as the relative contributions of fungal community to litter decomposition were studied. Results showed that long-term exposure to ZnO nanoparticles and visible light led to a significant decrease in litter decomposition rate (0.26 m -1 vs 0.45 m -1 ), and visible light would increase the inhibitory effect (0.24 m -1 ), which caused significant decrease in pH value of litter cultures, fungal sporulation rate, as well as most extracellular enzyme activities. The phototoxicity of ZnO nanoparticles also showed impacts on fungal community composition, especially on the genus of Varicosporium, whose abundance was significantly and positively related to decomposition rate. In conclusion, our study provides the evidence for negatively effects of ZnO NPs photocatalysis on ecological process of litter decomposition and highlights the contribution of visible light radiation to nanoparticles toxicity in freshwater ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Pyrite nanoparticles as a Fenton-like reagent for in situ remediation of organic pollutants

    Directory of Open Access Journals (Sweden)

    Carolina Gil-Lozano

    2014-06-01

    Full Text Available The Fenton reaction is the most widely used advanced oxidation process (AOP for wastewater treatment. This study reports on the use of pyrite nanoparticles and microparticles as Fenton reagents for the oxidative degradation of copper phthalocyanine (CuPc as a representative contaminant. Upon oxidative dissolution in water, pyrite (FeS2 particles can generate H2O2 at their surface while simultaneously promoting recycling of Fe3+ into Fe2+ and vice versa. Pyrite nanoparticles were synthesized by the hot injection method. The use of a high concentration of precursors gave individual nanoparticles (diameter: 20 nm with broader crystallinity at the outer interfaces, providing a greater number of surface defects, which is advantageous for generating H2O2. Batch reactions were run to monitor the kinetics of CuPc degradation in real time and the amount of H2O2. A markedly greater degradation of CuPc was achieved with nanoparticles as compared to microparticles: at low loadings (0.08 mg/L and 20 h reaction time, the former enabled 60% CuPc removal, whereas the latter enabled only 7% removal. These results confirm that the use of low concentrations of synthetic nanoparticles can be a cost effective alternative to conventional Fenton procedures for use in wastewater treatment, avoiding the potential risks caused by the release of heavy metals upon dissolution of natural pyrites.

  11. Gold nanoparticle-based optical microfluidic sensors for analysis of environmental pollutants

    DEFF Research Database (Denmark)

    Lafleur, Josiane P.; Senkbeil, Silja; Jensen, Thomas G.

    2012-01-01

    Conventional methods of environmental analysis can be significantly improved by the development of portable microscale technologies for direct in-field sensing at remote locations. This report demonstrates the vast potential of gold nanoparticle-based microfluidic sensors for the rapid, in......-field, detection of two important classes of environmental contaminants – heavy metals and pesticides. Using gold nanoparticle-based microfluidic sensors linked to a simple digital camera as the detector, detection limits as low as 0.6 μg L−1 and 16 μg L−1 could be obtained for the heavy metal mercury...... and the dithiocarbamate pesticide ziram, respectively. These results demonstrate that the attractive optical properties of gold nanoparticle probes combine synergistically with the inherent qualities of microfluidic platforms to offer simple, portable and sensitive sensors for environmental contaminants....

  12. Salinomycin nanoparticles interfere with tumor cell growth and the tumor microenvironment in an orthotopic model of pancreatic cancer.

    Science.gov (United States)

    Daman, Zahra; Faghihi, Homa; Montazeri, Hamed

    2018-05-02

    Recently, salinomycin (SAL) has been reported to inhibit proliferation and induce apoptosis in various tumors. The aim of this study was to deliver SAL to orthotopic model of pancreatic cancer by the aid of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs). The NPs were physico-chemically characterized and evaluated for cytotoxicity on luciferase-transduced AsPC-1 cells in vitro as well as implanted orthotopically into the pancreas of nude mice. SAL (3.5 mg/kg every other day) blocked tumor growth by 52% compared to the control group after 3 weeks of therapy. Western blotting of tumor protein extracts indicated that SAL treatment leads to up-regulation of E-cadherin, β-catenin, and transforming growth factor beta receptor (TGFβR) expressions in AsPC-1 orthotopic tumor. Noteworthy, immunofluorescence staining of adjacent tumor sections showed that treatment with SAL NPs cause significant apoptosis in the tumor cells rather than the stroma. Further investigations also revealed that TGFβR2 over-expression was induced in stroma cells after treatment with SAL NPs. These results highlight SAL-loaded PLGA NPs as a promising system for pancreatic cancer treatment, while the mechanistic questions need to be subsequently tested.

  13. Low-cost removal of organic pollutants with nickel nanoparticle loaded ordered macroporous hydrogel as high performance catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Mingyi, E-mail: tmyi@tjcu.edu.cn [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Huang, Guanbo, E-mail: gbhuang2007@hotmail.com [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Zhang, Sai [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Liu, Yue [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Li, Xianxian [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Wang, Xingrui [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Pang, Xiaobo [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Qiu, Haixia, E-mail: qhx@tju.edu.cn [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China)

    2014-06-01

    A facile route for the in situ preparation of catalytically active Ni nanoparticles (NPs) in ordered macroporous hydrogel (OMH) has been developed. The hydrogel was fabricated based on polystyrene colloid template. The electronegativity of amide and carboxyl groups on the poly(acrylamide-co-acryl acid) chains of the hydrogel caused strong binding of Ni{sup 2+} ions which made them distribute uniformly inside the hydrogel. When immersed in NaBH{sub 4} aqueous solution, the Ni{sup 2+} ions on the hydrogel were reduced to Ni NPs. The resultant Ni NPs loaded OMH showed good catalytic activity for the reduction of a common organic pollutant, 4-nitrophenol, with NaBH{sub 4}. A kinetic study of the catalytic reaction was carried out. The rate constant per unit weight could reach 0.53 s{sup −1} g{sup −1}, which is much better than many common hydrogel loaded nickel catalysts. Moreover, the current catalyst can be easily separated and recovered with stable catalytic activity. - Highlights: • A new poly(acrylamide-co-acryl acid) hydrogel with ordered macropores. • A simple in situ fabrication of nickel nanoparticles under mild conditions. • High-performance heterogeneous catalyst for removal of nitrophenol from water. • Good recyclability of catalyst without any complicated regeneration process.

  14. Nanoparticle pollution and associated increasing potential risks on environment and human health: a case study of China.

    Science.gov (United States)

    Gao, Yang; Yang, Tiantian; Jin, Jin

    2015-12-01

    The aims of this study are (1) to discuss the mechanism of nanoparticle lifecycle and estimate the impacts of its associated pollution on environment and human health; and (2) to provide recommendation to policy makers on how to leverage nanopollution and human health along with the rapid development of economics in China. Manufactured nanoparticles (MNPs) could either directly or indirectly impair human health and the environment. Exposures to MNP include many ways, such as via inhalation, ingestion, direct contact, or the use of consumer products over the lifecycle of the product. In China, the number of people exposed to MNP has been increasing year by year. To better provide medical care to people exposed to MNP, the Chinese government has established many disease control and prevention centers over China. However, the existing facilities and resources for controlling MNP are still not enough considering the number of people impacted by MNP and the number of ordinary workers in the MNP related industry applying for their occupational identification through the Center for Disease Control and Prevention. China should assess the apparent risk environment and human health being exposed to MNP and develop action plans to reduce the possibility of direct contacts between human beings and the emerging nanomaterials. In addition, we suggest more comprehensive studies on the MNP behavior and the development of quantitative approaches to measure MNP transport, and persistence should be carried out.

  15. Low-cost removal of organic pollutants with nickel nanoparticle loaded ordered macroporous hydrogel as high performance catalyst

    International Nuclear Information System (INIS)

    Tang, Mingyi; Huang, Guanbo; Zhang, Sai; Liu, Yue; Li, Xianxian; Wang, Xingrui; Pang, Xiaobo; Qiu, Haixia

    2014-01-01

    A facile route for the in situ preparation of catalytically active Ni nanoparticles (NPs) in ordered macroporous hydrogel (OMH) has been developed. The hydrogel was fabricated based on polystyrene colloid template. The electronegativity of amide and carboxyl groups on the poly(acrylamide-co-acryl acid) chains of the hydrogel caused strong binding of Ni 2+ ions which made them distribute uniformly inside the hydrogel. When immersed in NaBH 4 aqueous solution, the Ni 2+ ions on the hydrogel were reduced to Ni NPs. The resultant Ni NPs loaded OMH showed good catalytic activity for the reduction of a common organic pollutant, 4-nitrophenol, with NaBH 4 . A kinetic study of the catalytic reaction was carried out. The rate constant per unit weight could reach 0.53 s −1  g −1 , which is much better than many common hydrogel loaded nickel catalysts. Moreover, the current catalyst can be easily separated and recovered with stable catalytic activity. - Highlights: • A new poly(acrylamide-co-acryl acid) hydrogel with ordered macropores. • A simple in situ fabrication of nickel nanoparticles under mild conditions. • High-performance heterogeneous catalyst for removal of nitrophenol from water. • Good recyclability of catalyst without any complicated regeneration process

  16. Vault Nanoparticles Packaged with Enzymes as an Efficient Pollutant Biodegradation Technology.

    Science.gov (United States)

    Wang, Meng; Abad, Danny; Kickhoefer, Valerie A; Rome, Leonard H; Mahendra, Shaily

    2015-11-24

    Vault nanoparticles packaged with enzymes were synthesized as agents for efficiently degrading environmental contaminants. Enzymatic biodegradation is an attractive technology for in situ cleanup of contaminated environments because enzyme-catalyzed reactions are not constrained by nutrient requirements for microbial growth and often have higher biodegradation rates. However, the limited stability of extracellular enzymes remains a major challenge for practical applications. Encapsulation is a recognized method to enhance enzymatic stability, but it can increase substrate diffusion resistance, lower catalytic rates, and increase the apparent half-saturation constants. Here, we report an effective approach for boosting enzymatic stability by single-step packaging into vault nanoparticles. With hollow core structures, assembled vault nanoparticles can simultaneously contain multiple enzymes. Manganese peroxidase (MnP), which is widely used in biodegradation of organic contaminants, was chosen as a model enzyme in the present study. MnP was incorporated into vaults via fusion to a packaging domain called INT, which strongly interacts with vaults' interior surface. MnP fused to INT and vaults packaged with the MnP-INT fusion protein maintained peroxidase activity. Furthermore, MnP-INT packaged in vaults displayed stability significantly higher than that of free MnP-INT, with slightly increased Km value. Additionally, vault-packaged MnP-INT exhibited 3 times higher phenol biodegradation in 24 h than did unpackaged MnP-INT. These results indicate that the packaging of MnP enzymes in vault nanoparticles extends their stability without compromising catalytic activity. This research will serve as the foundation for the development of efficient and sustainable vault-based bioremediation approaches for removing multiple contaminants from drinking water and groundwater.

  17. Development of Combining of Human Bronchial Mucosa Models with XposeALI® for Exposure of Air Pollution Nanoparticles.

    Directory of Open Access Journals (Sweden)

    Jie Ji

    Full Text Available Exposure to agents via inhalation is of great concerns both in workplace environment and in the daily contact with particles in the ambient air. Reliable human airway exposure systems will most likely replace animal experiment in future toxicity assessment studies of inhaled agents.In this study, we successfully established a combination of an exposure system (XposeALI with 3D models mimicking both healthy and chronic bronchitis-like mucosa by co-culturing human primary bronchial epithelial cells (PBEC and fibroblast at air-liquid interface (ALI. Light-, confocal microscopy, scanning- and transmission electron microscopy, transepithelial electrical resistance (TEER measurement and RT-PCR were performed to identify how the PBEC differentiated under ALI culture condition. Both models were exposed to palladium (Pd nanoparticles which sized 6-10 nm, analogous to those released from modern car catalysts, at three different concentrations utilizing the XposeALI module of the PreciseInhale® exposure system.Exposing the 3D models to Pd nanoparticles induced increased secretion of IL-8, yet the chronic bronchitis-like model released significantly more IL-8 than the normal model. The levels of IL-8 in basal medium (BM and apical lavage medium (AM were in the same ranges, but the secretion of MMP-9 was significantly higher in the AM compared to the BM.This combination of relevant human bronchial mucosa models and sophisticated exposure system can mimic in vivo conditions and serve as a useful alternative animal testing tool when studying adverse effects in humans exposed to aerosols, air pollutants or particles in an occupational setting.

  18. Development of Combining of Human Bronchial Mucosa Models with XposeALI® for Exposure of Air Pollution Nanoparticles.

    Science.gov (United States)

    Ji, Jie; Hedelin, Anna; Malmlöf, Maria; Kessler, Vadim; Seisenbaeva, Gulaim; Gerde, Per; Palmberg, Lena

    2017-01-01

    Exposure to agents via inhalation is of great concerns both in workplace environment and in the daily contact with particles in the ambient air. Reliable human airway exposure systems will most likely replace animal experiment in future toxicity assessment studies of inhaled agents. In this study, we successfully established a combination of an exposure system (XposeALI) with 3D models mimicking both healthy and chronic bronchitis-like mucosa by co-culturing human primary bronchial epithelial cells (PBEC) and fibroblast at air-liquid interface (ALI). Light-, confocal microscopy, scanning- and transmission electron microscopy, transepithelial electrical resistance (TEER) measurement and RT-PCR were performed to identify how the PBEC differentiated under ALI culture condition. Both models were exposed to palladium (Pd) nanoparticles which sized 6-10 nm, analogous to those released from modern car catalysts, at three different concentrations utilizing the XposeALI module of the PreciseInhale® exposure system. Exposing the 3D models to Pd nanoparticles induced increased secretion of IL-8, yet the chronic bronchitis-like model released significantly more IL-8 than the normal model. The levels of IL-8 in basal medium (BM) and apical lavage medium (AM) were in the same ranges, but the secretion of MMP-9 was significantly higher in the AM compared to the BM. This combination of relevant human bronchial mucosa models and sophisticated exposure system can mimic in vivo conditions and serve as a useful alternative animal testing tool when studying adverse effects in humans exposed to aerosols, air pollutants or particles in an occupational setting.

  19. A simple and fast method based on mixed hemimicelles coated magnetite nanoparticles for simultaneous extraction of acidic and basic pollutants.

    Science.gov (United States)

    Asgharinezhad, Ali Akbar; Ebrahimzadeh, Homeira

    2016-01-01

    One of the considerable and disputable areas in analytical chemistry is a single-step simultaneous extraction of acidic and basic pollutants. In this research, a simple and fast coextraction of acidic and basic pollutants (with different polarities) with the aid of magnetic dispersive micro-solid phase extraction based on mixed hemimicelles assembly was introduced for the first time. Cetyltrimethylammonium bromide (CTAB)-coated Fe3O4 nanoparticles as an efficient sorbent was successfully applied to adsorb 4-nitrophenol and 4-chlorophenol as two acidic and chlorinated aromatic amines as basic model compounds. Using a central composite design methodology combined with desirability function approach, the optimal experimental conditions were evaluated. The opted conditions were pH = 10; concentration of CTAB = 0.86 mmol L(-1); sorbent amount = 55.5 mg; sorption time = 11.0 min; no salt addition to the sample, type, and volume of the eluent = 120 μL methanol containing 5% acetic acid and 0.01 mol L(-1) HCl; and elution time = 1.0 min. Under the optimum conditions, detection limits and linear dynamic ranges were achieved in the range of 0.05-0.1 and 0.25-500 μg L(-1), respectively. The percent of extraction recoveries and relative standard deviations (n = 5) were in the range of 71.4-98.0 and 4.5-6.5, respectively. The performance of the optimized method was certified by coextraction of other acidic and basic compounds. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of the target analytes in various water samples, and satisfactory results were obtained.

  20. 3D TiO2 submicrostructures decorated by silver nanoparticles as SERS substrate for organic pollutants detection and degradation

    International Nuclear Information System (INIS)

    Chen, Jianjun; Su, Huilan; You, Xueling; Gao, Jing; Lau, Woon Ming; Zhang, Di

    2014-01-01

    Graphical abstract: - Highlights: • Contrive a multifunctional SERS substrate with 3D sub-micrometer structure and multicomponent. • The blue wing of butterfly (Euploea mulciber) is used as template for Ag/TiO 2 nanocomposites. • The 3D submicrostructures Ag/TiO 2 presents superior SERS effect and photocatalytic activity. • Pave a facile route to prepare multifunctional material by utilizing smart structural designs in nature. - Abstract: The blue wing of butterfly Euploea mulciber is used as a template to generate Ag/TiO 2 nanocomposites. Thereinto, Ag nanoparticles are deposited uniformly onto TiO 2 substrate with three dimensional (3D) submicrometer structures. This unique 3D sub-micrometer structures featured with ridges, ribs and struts can provide a large number of active “hot spots” for enhanced Raman signal. Meanwhile, depositing Ag onto the TiO 2 surface can greatly boost its SERS effect and photocatalytic activity by bringing additional electrons into the molecules and inhibiting electrons–holes recombination. Thus, the as-prepared 3D Ag/TiO 2 submicrostructures can not only offer sensitive and reproducible SERS signals, but also present superior photocatalytic activity, which can be utilized to detect and eliminate organic pollutants

  1. Experimental and numerical analysis of traffic emitted nanoparticle and particulate matter dispersion at urban pollution hot-spots

    Science.gov (United States)

    Goel, Anju

    Road vehicles are a major source of airborne nanoparticles (traffic hot-spots such as traffic intersections (TIs), where pollution pockets are created due to frequently changing driving conditions. Recent trends suggest an exponential increase in travel demand and travelling time in the UK and elsewhere over the years, which indicate a growing need for the accurate characterisation of exposure at TIs since exposure at these hot-spots can contribute disproportionately high to overall commuting exposure. Based on field observations, this thesis aims (i) to investigate the traffic driving conditions in which TIs become a hotspot for nanoparticles and PM, (ii) to estimate the extent of road that is affected by high particle number concentrations (PNCs) and PM due to presence of a signal, (iii) to assess the vertical and horizontal variations in PNC and PMC at different TIs, (iv) to estimate the associated in-cabin and pedestrian exposure at TIs, and finally (v) to predict PNCs by using freely available models of air pollution at TIs. For this thesis, two sets of experiments (i.e. mobile- and fixed-sites) were carried out to measure airborne nanoparticles and PM in the size range of (0.005-10 ?m) using a fast response differential mobility spectrometer (DMS50) and a GRIMM particle spectrometer (1.107 E). Mobile measurements were made on a circle passing through 10 TIs and fixed-site measurements were carried out at two different types of TIs (i.e. 3- and 4-way). Dispersion modelling was then performed by using California Line Source (CALINE4) and California Line Source for Queueing and Hotspot Calculations (CAL3QHC) at TIs. Several important findings were then extrapolated during the analysis. These findings indicated that congested TIs were found to become hot-spots when vehicle accelerate from idling conditions. The average length of road in longitudinal direction that is affected by high PNCs and PM was found to be highest (148 m; 89 to -59 m from the center of a TI

  2. Photocatalytic effect of green synthesised CuO nanoparticles on selected environmental pollutants and pathogens

    Science.gov (United States)

    Fuku, Xolile; Thovhogi, Ntevheleni; Maaza, Malik

    2018-05-01

    Highly crystalline irregular green synthesised CuO nanoparticles (CuO NPs) which are 10 nm in particle size were successfully characterised by HRSEM and AFM. EDS confirmed the main components of prepared sample which are Cu and O. Meanwhile, UV/Vis revealed the reflectance, transmittance, absorbance and the semiconducting nature of the synthesised nano-oxides. The optical band gap of CuO NPs was calculated to be 1.4 - 2.3 eV which indicates that CuO NPs can be used in metal oxide semiconductor-based devices. CuO NPs were found to be excellent photocatalysts for the degradation of methyl orange organic dye under the illumination of artificial light irradiation. The experiments demonstrated that MO in aqueous solution was more efficiently photo-degraded (65 %) using CuO NPs as photocatalysts. Further, the nanomaterials were also found to be good inhibitors of bacterial strains at both low and high concentrations of 5 - 10 mg mL-1.

  3. Stabilized chitosan/Fe(0)-nanoparticle beads to remove heavy metals from polluted sediments.

    Science.gov (United States)

    Liu, T; Sun, Y; Wang, Z L

    2016-01-01

    Sediment contamination by heavy metals has become a widespread problem that can affect the normal behaviors of rivers and lakes. After chitosan/Fe(0)-nanoparticles (CS-NZVI) beads were cross-linked with glutaraldehyde (GLA), their mechanical strength, stability and separation efficiency from the sediment were obviously improved. Moreover, the average aperture size of GLA-CS-NZVI beads was 20.6 μm and NZVI particles were nearly spherical in shape with a mean diameter of 40.2 nm. In addition, the pH showed an insignificant effect on the removal rates from the sediment. Due to the dissolution of metals species into aqueous solutions as an introduction of the salt, the removal rates of all heavy metals from the sediment were increased with an increase of the salinity. The competitive adsorption of heavy metals between the sediment particles and GLA-CS-NZVI beads became stronger as the sediment particles became smaller, leading to decreased removal rates. Therefore, the removal efficiency could be enhanced by optimizing experimental conditions and choosing appropriate materials for the target contaminants.

  4. nanoparticles

    Science.gov (United States)

    Andreu-Cabedo, Patricia; Mondragon, Rosa; Hernandez, Leonor; Martinez-Cuenca, Raul; Cabedo, Luis; Julia, J. Enrique

    2014-10-01

    Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO3 + 40% KNO3) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable.

  5. Visible light photocatalytic activities of ZnFe_2O_4/ZnO nanoparticles for the degradation of organic pollutants

    International Nuclear Information System (INIS)

    Rameshbabu, R.; Kumar, Niraj; Karthigeyan, A.; Neppolian, B.

    2016-01-01

    ZnFe_2O_4/ZnO nanoparticles have been synthesized by co-precipitation method using polyvinyl alcohol (PVA) as surfactant. The phase formation of synthesized products was systematically investigated from powder X-ray diffraction. Cubic ZnFe_2O_4 and hexagonal ZnO were identified in accordance with different molar concentrations of Fe"3"+ ions. The morphology and functionality were analyzed using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The optical properties and change in the band gap from UV to visible region upon increasing molar concentration of Fe"3"+ ions were analyzed from diffuse reflectance spectra (DRS). Superparamagnetic property was observed for synthesized ZnFe_2O_4/ZnO nanoparticles using vibrating sample magnetometer (VSM). The methylene blue and methyl orange were taken as model dyes to illustrate the photocatalytic activity of synthesized products under visible light irradiation. Maximum degradation of 99% for methyl orange (MO) was achieved by the use of 13 nm sized ZnFe_2O_4/ZnO nanoparticles as catalyst and a minutely less activity was observed for the methylene blue (MB) degradation (98%), when the photocatalytic processes were carried out for 5 h and 6 h, respectively. - Highlights: • Co-precipitation method is proposed to synthesize magnetic nanoparticles. • Modifications in the molar concentration lead to the shift in absorption edge. • Superparamagnetic property is demonstrated for the nanoparticles. • Two dye pollutants are utilized to demonstrate the photocatalytic activity.

  6. Visible light photocatalytic activities of ZnFe{sub 2}O{sub 4}/ZnO nanoparticles for the degradation of organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Rameshbabu, R. [SRM Research Institute, SRM University, Kattankulathur, Kanchipuram 603203, Tamil Nadu (India); Kumar, Niraj [SRM Research Institute, SRM University, Kattankulathur, Kanchipuram 603203, Tamil Nadu (India); Centre for Materials Science and Nano Devices, Department of Physics and Nanotechnology, SRM University Kattankulathur, Kanchipuram 603203, Tamil Nadu (India); Karthigeyan, A., E-mail: karthigeyan.a@ktr.srmuniv.ac.in [Centre for Materials Science and Nano Devices, Department of Physics and Nanotechnology, SRM University Kattankulathur, Kanchipuram 603203, Tamil Nadu (India); Neppolian, B., E-mail: neppolian.b@res.srmuniv.ac.in [SRM Research Institute, SRM University, Kattankulathur, Kanchipuram 603203, Tamil Nadu (India)

    2016-09-15

    ZnFe{sub 2}O{sub 4}/ZnO nanoparticles have been synthesized by co-precipitation method using polyvinyl alcohol (PVA) as surfactant. The phase formation of synthesized products was systematically investigated from powder X-ray diffraction. Cubic ZnFe{sub 2}O{sub 4} and hexagonal ZnO were identified in accordance with different molar concentrations of Fe{sup 3+} ions. The morphology and functionality were analyzed using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The optical properties and change in the band gap from UV to visible region upon increasing molar concentration of Fe{sup 3+} ions were analyzed from diffuse reflectance spectra (DRS). Superparamagnetic property was observed for synthesized ZnFe{sub 2}O{sub 4}/ZnO nanoparticles using vibrating sample magnetometer (VSM). The methylene blue and methyl orange were taken as model dyes to illustrate the photocatalytic activity of synthesized products under visible light irradiation. Maximum degradation of 99% for methyl orange (MO) was achieved by the use of 13 nm sized ZnFe{sub 2}O{sub 4}/ZnO nanoparticles as catalyst and a minutely less activity was observed for the methylene blue (MB) degradation (98%), when the photocatalytic processes were carried out for 5 h and 6 h, respectively. - Highlights: • Co-precipitation method is proposed to synthesize magnetic nanoparticles. • Modifications in the molar concentration lead to the shift in absorption edge. • Superparamagnetic property is demonstrated for the nanoparticles. • Two dye pollutants are utilized to demonstrate the photocatalytic activity.

  7. Nickel nanoparticles-chitosan composite coated cellulose filter paper: An efficient and easily recoverable dip-catalyst for pollutants degradation.

    Science.gov (United States)

    Kamal, Tahseen; Khan, Sher Bahadar; Asiri, Abdullah M

    2016-11-01

    In this report, we used cellulose filter paper (FP) as high surface area catalyst supporting green substrate for the synthesis of nickel (Ni) nanoparticles in thin chitosan (CS) coating layer and their easy separation was demonstrated for next use. In this work, FP was coated with a 1 wt% CS solution onto cellulose FP to prepare CS-FP as an economical and environment friendly host material. CS-FP was put into 0.2 M NiCl 2 aqueous solution for the adsorption of Ni 2+ ions by CS coating layer. The Ni 2+ adsorbed CS-FP was treated with 0.1 M NaBH 4 aqueous solution to convert the ions into nanoparticles. Thus, we achieved Ni nanoparticles-CS composite through water based in-situ preparation process. Successful Ni nanoparticles formations was assessed by FESEM and EDX analyses. FTIR used to track the interactions between nanoparticles and host material. Furthermore, we demonstrated that the nanocomposite displays an excellent catalytic activity and reusability in three reduction reactions of toxic compounds i.e. conversion of 4-nitrophenol to 4-aminophenol, 2-nitrophenol to 2-aminophenol, and methyl orange dye reduction by NaBH 4 . Such a fabrication process of Ni/CS-FP may be applicable for the immobilization of other metal nanoparticles onto FP for various applications in catalysis, sensing, and environmental sciences. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Development of a hybrid photo-bioreactor and nanoparticle adsorbent system for the removal of CO2, and selected organic and metal co-pollutants.

    Science.gov (United States)

    Rocha, Andrea A; Wilde, Christian; Hu, Zhenzhong; Nepotchatykh, Oleg; Nazarenko, Yevgen; Ariya, Parisa A

    2017-07-01

    Fossil fuel combustion and many industrial processes generate gaseous emissions that contain a number of toxic organic pollutants and carbon dioxide (CO 2 ) which contribute to climate change and atmospheric pollution. There is a need for green and sustainable solutions to remove air pollutants, as opposed to conventional techniques which can be expensive, consume additional energy and generate further waste. We developed a novel integrated bioreactor combined with recyclable iron oxide nano/micro-particle adsorption interfaces, to remove CO 2, and undesired organic air pollutants using natural particles, while generating oxygen. This semi-continuous bench-scale photo-bioreactor was shown to successfully clean up simulated emission streams of up to 45% CO 2 with a conversion rate of approximately 4% CO 2 per hour, generating a steady supply of oxygen (6mmol/hr), while nanoparticles effectively remove several undesired organic by-products. We also showed algal waste of the bioreactor can be used for mercury remediation. We estimated the potential CO 2 emissions that could be captured from our new method for three industrial cases in which, coal, oil and natural gas were used. With a 30% carbon capture system, the reduction of CO 2 was estimated to decrease by about 420,000, 320,000 and 240,000 metric tonnes, respectively for a typical 500MW power plant. The cost analysis we conducted showed potential to scale-up, and the entire system is recyclable and sustainable. We further discuss the implications of usage of this complete system, or as individual units, that could provide a hybrid option to existing industrial setups. Copyright © 2016. Published by Elsevier B.V.

  9. Ag2WO4 nanorods decorated with AgI nanoparticles: Novel and efficient visible-light-driven photocatalysts for the degradation of water pollutants

    Directory of Open Access Journals (Sweden)

    Shijie Li

    2018-04-01

    Full Text Available To develop efficient and stable visible-light-driven (VLD photocatalysts for pollutant degradation, we synthesized novel heterojunction photocatalysts comprised of AgI nanoparticle-decorated Ag2WO4 nanorods via a facile method. Various characterization techniques, including XRD, SEM, TEM, EDX, and UV–vis DRS were used to investigate the morphology and optical properties of the as-prepared AgI/Ag2WO4 catalyst. With AgI acting as the cocatalyst, the resulting AgI/Ag2WO4 heterostructure shows excellent performance in degrading toxic, stable pollutants such as rhodamine B (RhB, methyl orange (MO and para-chlorophenol (4-CP. The high performance is attributed to the enhanced visible-light absorption properties and the promoted separation efficiency of charge carriers through the formation of the heterojunction between AgI and Ag2WO4. Additionally, AgI/Ag2WO4 exhibits durable stability. The active species trapping experiment reveals that active species (O2•− and h+ dominantly contribute to RhB degradation. The AgI/Ag2WO4 heterojunction photocatalyst characterized in this work holds great potential for remedying environmental issues due to its simple preparation method and excellent photocatalytic performance.

  10. Cobalt doped antimony oxide nano-particles based chemical sensor and photo-catalyst for environmental pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Jamal, Aslam [Centre for Advanced Materials and Nano-Engineering (CAMNE) and Department of Chemistry, Faculty of Sciences and Arts, Najran University, P. O. Box 1988, Najran 11001 (Saudi Arabia); Rahman, Mohammed M. [Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Khan, Sher Bahadar, E-mail: drkhanmarwat@gmail.com [Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Faisal, Mohd. [Centre for Advanced Materials and Nano-Engineering (CAMNE) and Department of Chemistry, Faculty of Sciences and Arts, Najran University, P. O. Box 1988, Najran 11001 (Saudi Arabia); Akhtar, Kalsoom [Division of Nano Sciences and Department of Chemistry, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Rub, Malik Abdul; Asiri, Abdullah M.; Al-Youbi, Abdulrahman O. [Center of Excellence for Advanced Materials Research (CEAMR), King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia); Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589 (Saudi Arabia)

    2012-11-15

    Graphical abstract: A dichloromethane chemical sensor using cobalt antimony oxides has been fabricated. This sensor showed high sensitivity and will be a useful candidate for environmental and health monitoring. Also it showed high photo-catalytic activity and can be a good candidate as a photo-catalyst for organic hazardous materials. Highlights: Black-Right-Pointing-Pointer Reusable chemical sensor. Black-Right-Pointing-Pointer Green environmental and eco-friendly chemi-sensor. Black-Right-Pointing-Pointer High sensitivity. Black-Right-Pointing-Pointer Good candidate for environmental and health monitoring. - Abstract: Cobalt doped antimony oxide nano-particles (NPs) have been synthesized by hydrothermal process and structurally characterized by utilizing X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Fourier transforms infrared spectrophotometer (FT-IR) which revealed that the synthesized cobalt antimony oxides (CoSb{sub 2}O{sub 6}) are well crystalline nano-particles with an average particles size of 26 {+-} 10 nm. UV-visible absorption spectra ({approx}286 nm) were used to investigate the optical properties of CoSb{sub 2}O{sub 6}. The chemical sensing of CoSb{sub 2}O{sub 6} NPs have been primarily investigated by I-V technique, where dichloromethane is used as a model compound. The analytical performance of dichloromethane chemical sensor exhibits high sensitivity (1.2432 {mu}A cm{sup -2} mM{sup -1}) and a large linear dynamic range (1.0 {mu}M-0.01 M) in short response time (10 s). The photo catalytic activity of the synthesized CoSb{sub 2}O{sub 6} nano-particles was evaluated by degradation of acridine orange (AO), which degraded 58.37% in 200 min. These results indicate that CoSb{sub 2}O{sub 6} nano-particles can play an excellent research impact in the environmental field.

  11. New composites of nanoparticle Cu (I) oxide and titania in a novel inorganic polymer (geopolymer) matrix for destruction of dyes and hazardous organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Falah, Mahroo [MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington (New Zealand); MacKenzie, Kenneth J.D., E-mail: Kenneth.mackenzie@vuw.ac.nz [MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington (New Zealand); Knibbe, Ruth [Robinson Research Institute, Victoria University of Wellington (New Zealand); Page, Samuel J.; Hanna, John V. [Department of Physics, Warwick University, Coventry CV4 7AL (United Kingdom)

    2016-11-15

    Highlights: • Synthesis reported of new photoactive nano-oxide composites in a geopolymer matrix. • The novel aluminosilicate matrix is expanded with cetyltrimethylammonium bromide. • The photoactive component consists of a Cu(I) oxide and titania heterostructure. • Composites remove the model pollutant by both adsorption and photodegradation. • These new photocatalysts are extremely efficient and ecologically friendly. - Abstract: New photoactive composites to efficiently remove organic dyes from water are reported. These consist of Cu{sub 2}O/TiO{sub 2} nanoparticles in a novel inorganic geopolymer matrix modified by a large tertiary ammonium species (cetyltrimethylammonium bromide, CTAB) whose presence in the matrix is demonstrated by FTIR spectroscopy. The CTAB does not disrupt the tetrahedral geopolymer structural silica and alumina units as demonstrated by {sup 29}Si and {sup 27}Al MAS NMR spectroscopy. SEM/EDS, TEM and BET measurements suggest that the Cu{sub 2}O/TiO{sub 2} nanoparticles are homogenously distributed on the surface and within the geopolymer pores. The mechanism of removal of methylene blue (MB) dye from solution consists of a combination of adsorption (under dark conditions) and photodegradation (under UV radiation). MB adsorption in the dark follows pseudo second-order kinetics and is described by Freundlich-Langmuir type isotherms. The performance of the CTAB-modified geopolymer based composites is superior to composites based on unmodified geopolymer hosts, the most effective composite containing 5 wt% Cu{sub 2}O/TiO{sub 2} in a CTAB-modified geopolymer host. These composites constitute a new class of materials with excellent potential in environmental protection applications.

  12. IETS and quantum interference

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo; Gagliardi, Alessio; Pecchia, Alessandro

    2014-01-01

    Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low...... suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference....

  13. 3D TiO{sub 2} submicrostructures decorated by silver nanoparticles as SERS substrate for organic pollutants detection and degradation

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jianjun [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Su, Huilan, E-mail: hlsu@sjtu.edu.cn [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); You, Xueling; Gao, Jing [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Lau, Woon Ming [Chengdu Green Energy and Green Manufacturing Technology R and D Center, Sichuan 610207 (China); Beijing Computational Science Research Center, Beijing 100084 (China); Zhang, Di, E-mail: zhangdi@sjtu.edu.cn [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2014-01-01

    Graphical abstract: - Highlights: • Contrive a multifunctional SERS substrate with 3D sub-micrometer structure and multicomponent. • The blue wing of butterfly (Euploea mulciber) is used as template for Ag/TiO{sub 2} nanocomposites. • The 3D submicrostructures Ag/TiO{sub 2} presents superior SERS effect and photocatalytic activity. • Pave a facile route to prepare multifunctional material by utilizing smart structural designs in nature. - Abstract: The blue wing of butterfly Euploea mulciber is used as a template to generate Ag/TiO{sub 2} nanocomposites. Thereinto, Ag nanoparticles are deposited uniformly onto TiO{sub 2} substrate with three dimensional (3D) submicrometer structures. This unique 3D sub-micrometer structures featured with ridges, ribs and struts can provide a large number of active “hot spots” for enhanced Raman signal. Meanwhile, depositing Ag onto the TiO{sub 2} surface can greatly boost its SERS effect and photocatalytic activity by bringing additional electrons into the molecules and inhibiting electrons–holes recombination. Thus, the as-prepared 3D Ag/TiO{sub 2} submicrostructures can not only offer sensitive and reproducible SERS signals, but also present superior photocatalytic activity, which can be utilized to detect and eliminate organic pollutants.

  14. Biogenic robust synthesis of silver nanoparticles using Punica granatum peel and its application as a green catalyst for the reduction of an anthropogenic pollutant 4-nitrophenol

    Science.gov (United States)

    Edison, T. Jebakumar Immanuel; Sethuraman, M. G.

    2013-03-01

    A robust synthesis of silver nanoparticles (AgNPs) using the peel extract of Punica granatum is reported in this article. The formation of AgNPs was confirmed by the appearance of brownish yellow color and the Surface Plasmon Resonance (SPR) peak at 432 nm. The biogenic AgNPs were found to have the size approximately 30 nm with distorted spherical shape. The high negative zeta potential values of AgNPs revealed their high stability which could be attributed to the capping of AgNPs by the phytoconstituents of the Punica granatum peel. The biogenic AgNPs were also found to function as an effective green catalyst in the reduction of anthropogenic pollutant viz., 4-nitrophenol (4-NP) by solid sodium borohydride, which was evident from the instantaneous color change of bright yellow (400 nm) to colorless (294 nm) solution, after the addition of AgNPs. The catalytic action of biogenic AgNPs in the reduction of 4-NP could be explained on the basis of Langmuir-Hinshelwood model.

  15. Encapsulation of gold nanoparticles into self-assembling protein nanoparticles

    Directory of Open Access Journals (Sweden)

    Yang Yongkun

    2012-10-01

    Full Text Available Abstract Background Gold nanoparticles are useful tools for biological applications due to their attractive physical and chemical properties. Their applications can be further expanded when they are functionalized with biological molecules. The biological molecules not only provide the interfaces for interactions between nanoparticles and biological environment, but also contribute their biological functions to the nanoparticles. Therefore, we used self-assembling protein nanoparticles (SAPNs to encapsulate gold nanoparticles. The protein nanoparticles are formed upon self-assembly of a protein chain that is composed of a pentameric coiled-coil domain at the N-terminus and trimeric coiled-coil domain at the C-terminus. The self-assembling protein nanoparticles form a central cavity of about 10 nm in size, which is ideal for the encapsulation of gold nanoparticles with similar sizes. Results We have used SAPNs to encapsulate several commercially available gold nanoparticles. The hydrodynamic size and the surface coating of gold nanoparticles are two important factors influencing successful encapsulation by the SAPNs. Gold nanoparticles with a hydrodynamic size of less than 15 nm can successfully be encapsulated. Gold nanoparticles with citrate coating appear to have stronger interactions with the proteins, which can interfere with the formation of regular protein nanoparticles. Upon encapsulation gold nanoparticles with polymer coating interfere less strongly with the ability of the SAPNs to assemble into nanoparticles. Although the central cavity of the SAPNs carries an overall charge, the electrostatic interaction appears to be less critical for the efficient encapsulation of gold nanoparticles into the protein nanoparticles. Conclusions The SAPNs can be used to encapsulate gold nanoparticles. The SAPNs can be further functionalized by engineering functional peptides or proteins to either their N- or C-termini. Therefore encapsulation of gold

  16. Megacity pollution by modern Diesel cars: New insights into the nature and formation of volatile nano-particles with high lung intrusion efficiency

    Science.gov (United States)

    Arnold, F.; Reichl, U.; Muschik, Ch.; Roiger, A.; Schlager, H.; Pirjola, L.; Rönkkö, T.; Keskinen, J.; Rothe, D.; Lähde, T.

    2009-04-01

    Aerosol particles generated by Diesel vehicles represent mayor health affecting air pollutants in cities and near motor ways. To mitigate the Diesel particle pollution problem, Diesel vehicles become increasingly fitted or retro-fitted with modern exhaust after treatment systems (ATS), which remove most engine-generated primary particles, particularly soot. Unfortunately however, ATS have undesired side effects including also the formation of low vapour pressure gases, which may undergo nucleation and condensation leading to volatile nucleation particles (NUP). NUP are substantially smaller (diameters: 5-15 nm) than soot particles (diameters: 40-100 nm), and therefore may be termed real nano-particles. NUP can intrude with maximum efficiency the lowest, least protected, and most vulnerable compartment of the human lung. However, the chemical nature and mechanism of formation of NUP are only poorly explored. Using a novel mass spectrometric method, we have made the first on line and off line measurements of low vapour pressure NUP precursor gases in the exhaust of a modern heavy duty Diesel vehicle engine, operated with and without ATS and combusting low and ultra-low sulphur fuels including also bio fuel. In addition, we have made accompanying NUP measurements and NUP model simulations. The on line measurements involved a CIMS (Chemical Ionization Mass Spectrometry) method originally developed by MPIK. They took place directly in the Diesel exhaust and had a large sensitivity and a fast time response (1 s). The off line measurements involved adsorption of exhaust gases on stainless steel, followed by thermo desorption and detection of desorbed exhaust molecules by CIMS. We find that modern Diesel ATS strongly increase the formation of hydroxyl radicals, which induce conversion of fuel sulphur to the important NUP precursor gaseous sulphuric acid. We also find that appreciable amounts of di-carboxylic acids survive the passage of the ATS or are even formed by the

  17. Interference lithography for optical devices and coatings

    Science.gov (United States)

    Juhl, Abigail Therese

    Interference lithography can create large-area, defect-free nanostructures with unique optical properties. In this thesis, interference lithography will be utilized to create photonic crystals for functional devices or coatings. For instance, typical lithographic processing techniques were used to create 1, 2 and 3 dimensional photonic crystals in SU8 photoresist. These structures were in-filled with birefringent liquid crystal to make active devices, and the orientation of the liquid crystal directors within the SU8 matrix was studied. Most of this thesis will be focused on utilizing polymerization induced phase separation as a single-step method for fabrication by interference lithography. For example, layered polymer/nanoparticle composites have been created through the one-step two-beam interference lithographic exposure of a dispersion of 25 and 50 nm silica particles within a photopolymerizable mixture at a wavelength of 532 nm. In the areas of constructive interference, the monomer begins to polymerize via a free-radical process and concurrently the nanoparticles move into the regions of destructive interference. The holographic exposure of the particles within the monomer resin offers a single-step method to anisotropically structure the nanoconstituents within a composite. A one-step holographic exposure was also used to fabricate self-healing coatings that use water from the environment to catalyze polymerization. Polymerization induced phase separation was used to sequester an isocyanate monomer within an acrylate matrix. Due to the periodic modulation of the index of refraction between the monomer and polymer, the coating can reflect a desired wavelength, allowing for tunable coloration. When the coating is scratched, polymerization of the liquid isocyanate is catalyzed by moisture in air; if the indices of the two polymers are matched, the coatings turn transparent after healing. Interference lithography offers a method of creating multifunctional self

  18. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution — ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  19. Dark Matter Interference

    DEFF Research Database (Denmark)

    Del Nobile, Eugenio; Kouvaris, Christoforos; Sannino, Francesco

    2012-01-01

    We study different patterns of interference in WIMP-nuclei elastic scattering that can accommodate the DAMA and CoGeNT experiments via an isospin violating ratio $f_n/f_p=-0.71$. We study interference between the following pairs of mediators: Z and Z', Z' and Higgs, and two Higgs fields. We show ...

  20. Palladium nanoparticles encapsulated in core-shell silica: A structured hydrogenation catalyst with enhanced activity for reduction of oxyanion water pollutants

    KAUST Repository

    Wang, Yin; Liu, Jinyong; Wang, Peng; Werth, Charles; Strathmann, Timothy J.

    2014-01-01

    Noble metal nanoparticles have been applied to mediate catalytic removal of toxic oxyanions and halogenated hydrocarbons in contaminated water using H2 as a clean and sustainable reductant. However, activity loss by nanoparticle aggregation and difficulty of nanoparticle recovery are two major challenges to widespread technology adoption. Herein, we report the synthesis of a core-shell-structured catalyst with encapsulated Pd nanoparticles and its enhanced catalytic activity in reduction of bromate (BrO3-), a regulated carcinogenic oxyanion produced during drinking water disinfection process, using 1 atm H2 at room temperature. The catalyst material consists of a nonporous silica core decorated with preformed octahedral Pd nanoparticles that were further encapsulated within an ordered mesoporous silica shell (i.e., SiO2@Pd@mSiO2). Well-defined mesopores (2.3 nm) provide a physical barrier to prevent Pd nanoparticle (6 nm) movement, aggregation, and detachment from the support into water. Compared to freely suspended Pd nanoparticles and SiO2@Pd, encapsulation in the mesoporous silica shell significantly enhanced Pd catalytic activity (by a factor of 10) under circumneutral pH conditions that are most relevant to water purification applications. Mechanistic investigation of material surface properties combined with Langmuir-Hinshelwood modeling of kinetic data suggest that mesoporous silica shell enhances activity by promoting BrO3- adsorption near the Pd active sites. The dual function of the mesoporous shell, enhancing Pd catalyst activity and preventing aggregation of active nanoparticles, suggests a promising general strategy of using metal nanoparticle catalysts for water purification and related aqueous-phase applications.

  1. Palladium nanoparticles encapsulated in core-shell silica: A structured hydrogenation catalyst with enhanced activity for reduction of oxyanion water pollutants

    KAUST Repository

    Wang, Yin

    2014-10-03

    Noble metal nanoparticles have been applied to mediate catalytic removal of toxic oxyanions and halogenated hydrocarbons in contaminated water using H2 as a clean and sustainable reductant. However, activity loss by nanoparticle aggregation and difficulty of nanoparticle recovery are two major challenges to widespread technology adoption. Herein, we report the synthesis of a core-shell-structured catalyst with encapsulated Pd nanoparticles and its enhanced catalytic activity in reduction of bromate (BrO3-), a regulated carcinogenic oxyanion produced during drinking water disinfection process, using 1 atm H2 at room temperature. The catalyst material consists of a nonporous silica core decorated with preformed octahedral Pd nanoparticles that were further encapsulated within an ordered mesoporous silica shell (i.e., SiO2@Pd@mSiO2). Well-defined mesopores (2.3 nm) provide a physical barrier to prevent Pd nanoparticle (6 nm) movement, aggregation, and detachment from the support into water. Compared to freely suspended Pd nanoparticles and SiO2@Pd, encapsulation in the mesoporous silica shell significantly enhanced Pd catalytic activity (by a factor of 10) under circumneutral pH conditions that are most relevant to water purification applications. Mechanistic investigation of material surface properties combined with Langmuir-Hinshelwood modeling of kinetic data suggest that mesoporous silica shell enhances activity by promoting BrO3- adsorption near the Pd active sites. The dual function of the mesoporous shell, enhancing Pd catalyst activity and preventing aggregation of active nanoparticles, suggests a promising general strategy of using metal nanoparticle catalysts for water purification and related aqueous-phase applications.

  2. Interference and Sensitivity Analysis.

    Science.gov (United States)

    VanderWeele, Tyler J; Tchetgen Tchetgen, Eric J; Halloran, M Elizabeth

    2014-11-01

    Causal inference with interference is a rapidly growing area. The literature has begun to relax the "no-interference" assumption that the treatment received by one individual does not affect the outcomes of other individuals. In this paper we briefly review the literature on causal inference in the presence of interference when treatments have been randomized. We then consider settings in which causal effects in the presence of interference are not identified, either because randomization alone does not suffice for identification, or because treatment is not randomized and there may be unmeasured confounders of the treatment-outcome relationship. We develop sensitivity analysis techniques for these settings. We describe several sensitivity analysis techniques for the infectiousness effect which, in a vaccine trial, captures the effect of the vaccine of one person on protecting a second person from infection even if the first is infected. We also develop two sensitivity analysis techniques for causal effects in the presence of unmeasured confounding which generalize analogous techniques when interference is absent. These two techniques for unmeasured confounding are compared and contrasted.

  3. Binaural Interference: Quo Vadis?

    Science.gov (United States)

    Jerger, James; Silman, Shlomo; Silverman, Carol; Emmer, Michele

    2017-04-01

    The reality of the phenomenon of binaural interference with speech recognition has been debated for two decades. Research has taken one of two avenues; group studies or case reports. In group studies, a sample of the elderly population is tested on speech recognition under three conditions; binaural, monaural right and monaural left. The aim is to determine the percent of the sample in which the expected outcome (binaural score-better-than-either-monaural score) is reversed (i.e., one of the monaural scores is better than the binaural score). This outcome has been commonly used to define binaural interference. The object of group studies is to answer the "how many" question, what is the prevalence of binaural interference in the sample. In case reports the binaural interference conclusion suggested by the speech recognition tests is not accepted until it has been corroborated by other independent diagnostic audiological measures. The aim is to attempt to determine the basis for the findings, to answer the "why" question. This article is at once tutorial, editorial and a case report. We argue that it is time to accept the reality of the phenomenon of binaural interference, to eschew group statistical approaches in search of an answer to the "how many" question, and to focus on individual case reports in search of an answer to the "why" question. American Academy of Audiology.

  4. Marine pollution

    International Nuclear Information System (INIS)

    Albaiges, J.

    1989-01-01

    This book covers the following topics: Transport of marine pollutants; Transformation of pollutants in the marine environment; Biological effects of marine pollutants; Sources and transport of oil pollutants in the Persian Gulf; Trace metals and hydrocarbons in Syrian coastal waters; and Techniques for analysis of trace pollutants

  5. Generalized Multiphoton Quantum Interference

    Directory of Open Access Journals (Sweden)

    Max Tillmann

    2015-10-01

    Full Text Available Nonclassical interference of photons lies at the heart of optical quantum information processing. Here, we exploit tunable distinguishability to reveal the full spectrum of multiphoton nonclassical interference. We investigate this in theory and experiment by controlling the delay times of three photons injected into an integrated interferometric network. We derive the entire coincidence landscape and identify transition matrix immanants as ideally suited functions to describe the generalized case of input photons with arbitrary distinguishability. We introduce a compact description by utilizing a natural basis that decouples the input state from the interferometric network, thereby providing a useful tool for even larger photon numbers.

  6. Interference in immunoassay

    International Nuclear Information System (INIS)

    Chapman, R.S.

    1998-01-01

    Interfering factors are evident in both limited reagent (radioimmunoassay) and excess reagent (immunometric assay) technologies and should be suspected whenever there is a discrepancy between analytical results and clinical findings in the investigation of particular diseases. The overall effect of interference in immunoassay is analytical bias in result, either positive or negative of variable magnitude. The interference maybe caused by a wide spectrum of factors from poor sample collection and handling to physiological factors e.g. lipaemia, heparin treatment, binding protein abnormalities, autoimmunity and drug treatments. The range of interfering factors is extensive and difficult to discuss effectively in a short review

  7. Water Pollution

    Science.gov (United States)

    Bowen, H. J. M.

    1975-01-01

    Deals with water pollution in the following categories: a global view, self purification, local pollution, difficulties in chemical analysis, and remedies for water pollution. Emphasizes the extent to which man's activities have modified the cycles of certain elements. (GS)

  8. Air Pollution

    Science.gov (United States)

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  9. Laser Interference Lithography

    NARCIS (Netherlands)

    van Wolferen, Hendricus A.G.M.; Abelmann, Leon; Hennessy, Theodore C.

    In this chapter we explain how submicron gratings can be prepared by Laser Interference Lithography (LIL). In this maskless lithography technique, the standing wave pattern that exists at the intersection of two coherent laser beams is used to expose a photosensitive layer. We show how to build the

  10. Kvantová interference

    Czech Academy of Sciences Publication Activity Database

    Peřina, Jan

    2003-01-01

    Roč. 48, č. 4 (2003), s. 99-103 ISSN 0447-6441 R&D Projects: GA MŠk LN00A015 Institutional research plan: CEZ:AV0Z1010921 Keywords : interference * quantum cryptography * quantum computing * quantum teleportation Subject RIV: BH - Optics, Masers, Lasers

  11. Interferometric detection of single gold nanoparticles calibrated against TEM size distributions

    DEFF Research Database (Denmark)

    Zhang, Lixue; Christensen, Sune; Bendix, Pól Martin

    2015-01-01

    Single nanoparticle analysis: An interferometric optical approach calibrates sizes of gold nanoparticles (AuNPs) from the interference intensities by calibrating their interferometric signals against the corresponding transmission electron microscopy measurements. This method is used to investigate...

  12. Synthesis and characterization of cobalt/gold bimetallic nanoparticles

    International Nuclear Information System (INIS)

    Cheng, Guangjun; Hight Walker, Angela R.

    2007-01-01

    Cobalt/gold (Co/Au) bimetallic nanoparticles are prepared by chemically reducing gold (III) chloride to gold in the presence of pre-synthesized Co nanoparticles. Transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption spectrometry, and a superconducting quantum interference device (SQUID) magnetometer have been used to characterize as-prepared bimetallic nanoparticles. Our findings demonstrate Au not only grows onto Co nanoparticles, forming a surface coating, but also diffuses into Co nanoparticles. The introduction of Au alters the crystalline structure of Co nanoparticles and changes their magnetic properties. Dodecanethiols induce a reorganization of as-prepared Co/Au bimetallic nanoparticles

  13. Codebook-based interference alignment for uplink MIMO interference channels

    KAUST Repository

    Lee, Hyun Ho; Park, Kihong; Ko, Youngchai; Alouini, Mohamed-Slim

    2014-01-01

    In this paper, we propose a codebook-based interference alignment (IA) scheme in the constant multiple-input multipleoutput (MIMO) interference channel especially for the uplink scenario. In our proposed scheme, we assume cooperation among base

  14. Visible light-driven photocatalytic degradation of the organic pollutant methylene blue with hybrid palladium–fluorine-doped titanium oxide nanoparticles

    International Nuclear Information System (INIS)

    Lázaro-Navas, Sonia; Prashar, Sanjiv; Fajardo, Mariano; Gómez-Ruiz, Santiago

    2015-01-01

    The synthesis of mesoporous aggregates of titanium oxide nanoparticles (F0) is described using a very cheap and simple synthetic protocol. This consists of the reaction of titanium tetraisopropoxide and a solution of HNO 3 in water (pH 2.0) and subsequent filtration. In addition, fluorine-doped titanium oxides (F1, F2, F5 and F10) were synthesized using the same method, adding increasing amounts of NaF to the reaction mixture (avoiding the use of expensive reagents such as NH 4 F or trifluoroacetic acid). The resulting materials were calcined at different temperatures (500, 600 and 650 °C) giving particles sized between 10 and 20 nm. Furthermore, a hybrid F-doped TiO 2 with supported palladium nanoparticles of ca. 20 nm (F5-500-Pd1) was synthesized by grafting an organometallic palladium(II) salt namely [Pd(cod)Cl 2 ] (cod = 1,5-cyclooctadiene). Photocatalytic studies of the degradation of methylene blue (MB) were carried out under UV light using all the synthesized material (non-doped an F-doped TiO 2 ), observing that the increase in the quantity of fluorine has a positive effect on the photocatalytic activity. F5-500 is apparently the material which has the most convenient structural properties (in terms of surface area and anatase/rutile ratio) and thus a higher photocatalytic activity. The hybrid material F-doped TiO 2 –Pd nanoparticles (F5-500-Pd1) has a lower band gap value than F5-500, and thus photocatalytic degradation of MB under LED visible light was achieved using F5-500-Pd1 as photocatalyst

  15. Visible light-driven photocatalytic degradation of the organic pollutant methylene blue with hybrid palladium–fluorine-doped titanium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lázaro-Navas, Sonia; Prashar, Sanjiv; Fajardo, Mariano; Gómez-Ruiz, Santiago, E-mail: santiago.gomez@urjc.es [Universidad Rey Juan Carlos, Departamento de Biología y Geología, Física y Química Inorgánica, ESCET (Spain)

    2015-02-15

    The synthesis of mesoporous aggregates of titanium oxide nanoparticles (F0) is described using a very cheap and simple synthetic protocol. This consists of the reaction of titanium tetraisopropoxide and a solution of HNO{sub 3} in water (pH 2.0) and subsequent filtration. In addition, fluorine-doped titanium oxides (F1, F2, F5 and F10) were synthesized using the same method, adding increasing amounts of NaF to the reaction mixture (avoiding the use of expensive reagents such as NH{sub 4}F or trifluoroacetic acid). The resulting materials were calcined at different temperatures (500, 600 and 650 °C) giving particles sized between 10 and 20 nm. Furthermore, a hybrid F-doped TiO{sub 2} with supported palladium nanoparticles of ca. 20 nm (F5-500-Pd1) was synthesized by grafting an organometallic palladium(II) salt namely [Pd(cod)Cl{sub 2}] (cod = 1,5-cyclooctadiene). Photocatalytic studies of the degradation of methylene blue (MB) were carried out under UV light using all the synthesized material (non-doped an F-doped TiO{sub 2}), observing that the increase in the quantity of fluorine has a positive effect on the photocatalytic activity. F5-500 is apparently the material which has the most convenient structural properties (in terms of surface area and anatase/rutile ratio) and thus a higher photocatalytic activity. The hybrid material F-doped TiO{sub 2}–Pd nanoparticles (F5-500-Pd1) has a lower band gap value than F5-500, and thus photocatalytic degradation of MB under LED visible light was achieved using F5-500-Pd1 as photocatalyst.

  16. Electromagnetic interference: a radiant future!

    NARCIS (Netherlands)

    Leferink, Frank Bernardus Johannes

    2015-01-01

    Although Electromagnetic Interference and Electromagnetic Compatibility are well established domains, the introduction of new technologies results in new challenges. Changes in both measurement techniques, and technological trends resulting in new types of interference are described. These are the

  17. Role of snow and cold environment in the fate and effects of nanoparticles and select organic pollutants from gasoline engine exhaust.

    Science.gov (United States)

    Nazarenko, Yevgen; Kurien, Uday; Nepotchatykh, Oleg; Rangel-Alvarado, Rodrigo B; Ariya, Parisa A

    2016-02-01

    Exposure to vehicle exhaust can drive up to 70 % of excess lifetime cancer incidences due to air pollution in urban environments. Little is known about how exhaust-derived particles and organic pollutants, implicated in adverse health effects, are affected by freezing ambient temperatures and the presence of snow. Airborne particles and (semi)volatile organic constituents in dilute exhaust were studied in a novel low-temperature environmental chamber system containing natural urban snow under controlled cold environmental conditions. The presence of snow altered the aerosol size distributions of dilute exhaust in the 10 nm to 10 μm range and decreased the number density of the nanoparticulate (snow from 0.218 ± 0.014 to 0.539 ± 0.009 mg L(-1), and over 40 additional (semi)volatile organic compounds and a large number of exhaust-derived carbonaceous and likely organic particles were identified. The concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX) increased from near the detection limit to 52.48, 379.5, 242.7, and 238.1 μg kg(-1) (± 10 %), respectively, indicating the absorption of exhaust-derived toxic organic compounds by snow. The alteration of exhaust aerosol size distributions at freezing temperatures and in the presence of snow, accompanied by changes of the organic pollutant content in snow, has potential to alter health effects of human exposure to vehicle exhaust.

  18. Hierarchical top-porous/bottom-tubular TiO 2 nanostructures decorated with Pd nanoparticles for efficient photoelectrocatalytic decomposition of synergistic pollutants

    KAUST Repository

    Zhang, Zhonghai

    2012-02-22

    In this paper, top-porous and bottom-tubular TiO 2 nanotubes (TiO 2 NTs) loaded with palladium nanoparticles (Pd/TiO 2 NTs) were fabricated as an electrode for an enhanced photoelectrocatalytic (PEC) activity toward organic dye decomposition. TiO 2 NTs with a unique hierarchical top-porous and bottom-tubular structure were prepared by a facile two-step anodization method and Pd nanoparticles were decorated onto the TiO 2 NTs via a photoreduction process. The PEC activity of Pd/TiO 2 NTs was investigated by decomposition of methylene blue (MB) and Rhodamine B (RhB). Because of formation Schottky junctions between TiO 2 and Pd, which significantly promoted the electron transfer and reduced the recombination of photogenerated electrons and holes, the Pd/TiO 2 NT electrode showed significantly higher PEC activities than TiO 2 NTs. Interestingly, an obvious synergy between two dyes was observed and corresponding mechanism based on facilitated transfer of electrons and holes as a result of a suitable energy level alignment was suggested. The findings of this work provide a fundamental insight not only into the fabrication but also utility of Schottky junctions for enhanced environmental remediation processes. © 2012 American Chemical Society.

  19. Evaluation of nanoparticle immunotoxicity

    Science.gov (United States)

    Dobrovolskaia, Marina A.; Germolec, Dori R.; Weaver, James L.

    2009-07-01

    The pharmaceutical industry is developing increasing numbers of drugs and diagnostics based on nanoparticles, and evaluating the immune response to these diverse formulations has become a challenge for scientists and regulatory agencies alike. An international panel of scientists and representatives from various agencies and companies reviewed the imitations of current tests at a workshop held at the National Cancer Institute in Frederick, Maryland. This article outlines practical strategies for identifying and controlling interferences in common evaluation methods and the implications for regulation.

  20. Leakage radiation interference microscopy.

    Science.gov (United States)

    Descrovi, Emiliano; Barakat, Elsie; Angelini, Angelo; Munzert, Peter; De Leo, Natascia; Boarino, Luca; Giorgis, Fabrizio; Herzig, Hans Peter

    2013-09-01

    We present a proof of principle for a new imaging technique combining leakage radiation microscopy with high-resolution interference microscopy. By using oil immersion optics it is demonstrated that amplitude and phase can be retrieved from optical fields, which are evanescent in air. This technique is illustratively applied for mapping a surface mode propagating onto a planar dielectric multilayer on a thin glass substrate. The surface mode propagation constant estimated after Fourier transformation of the measured complex field is well matched with an independent measurement based on back focal plane imaging.

  1. Intervention of radiation‐induced skin fibrosis by RNA interference

    DEFF Research Database (Denmark)

    Nawroth, Isabel

    ‐α (TNFα) production by macrophages might promote RIF. RNA interference (RNAi) is an evolutionary conserved gene‐silencing mechanism capable of degrading mRNA containing a homologous sequence to an exogenously introduced double stranded small interfering RNA (siRNA). These siRNAs can induce RNAi...... and inhibit the expression of target proteins. Therefore, siRNAs are considered as promising therapeutics for treatment of various diseases including genetic and viral diseases, and cancer. In this study, the therapeutic potential of RNA interference was investigated as an intervention strategy for radiation......‐induced skin fibrosis. Chitosan‐based nanoparticles (or polyplexes) formed by self‐assembly with siRNA were applied to overcome extracellular and intracellular barriers and deliver siRNA site‐specific. In this work we show that intraperitoneal administration of chitosan/DsiRNA nanoparticles targeting TNFα...

  2. Water pollution

    OpenAIRE

    Institute, Marine

    2013-01-01

    Students will learn about what causes water pollution and how to be environmentally aware. *Note: Students should understand the concept of the water cycle before moving onto water pollution (see Lesson Plan “Oceans all Around Us”).

  3. The intention interference effect.

    Science.gov (United States)

    Cohen, Anna-Lisa; Kantner, Justin; Dixon, Roger A; Lindsay, D Stephen

    2011-01-01

    Intentions have been shown to be more accessible (e.g., more quickly and accurately recalled) compared to other sorts of to-be-remembered information; a result termed an intention superiority effect (Goschke & Kuhl, 1993). In the current study, we demonstrate an intention interference effect (IIE) in which color-naming performance in a Stroop task was slower for words belonging to an intention that participants had to remember to carry out (Do-the-Task condition) versus an intention that did not have to be executed (Ignore-the-Task condition). In previous work (e.g., Cohen et al., 2005), having a prospective intention in mind was confounded with carrying a memory load. In Experiment 1, we added a digit-retention task to control for effects of cognitive load. In Experiment 2, we eliminated the memory confound in a new way, by comparing intention-related and control words within each trial. Results from both Experiments 1 and 2 revealed an IIE suggesting that interference is very specific to the intention, not just to a memory load.

  4. Beamforming design with proactive interference cancelation in MISO interference channels

    Science.gov (United States)

    Li, Yang; Tian, Yafei; Yang, Chenyang

    2015-12-01

    In this paper, we design coordinated beamforming at base stations (BSs) to facilitate interference cancelation at users in interference networks, where each BS is equipped with multiple antennas and each user is with a single antenna. By assuming that each user can select the best decoding strategy to mitigate the interference, either canceling the interference after decoding when it is strong or treating it as noise when it is weak, we optimize the beamforming vectors that maximize the sum rate for the networks under different interference scenarios and find the solutions of beamforming with closed-form expressions. The inherent design principles are then analyzed, and the performance gain over passive interference cancelation is demonstrated through simulations in heterogeneous cellular networks.

  5. Water Pollution

    International Nuclear Information System (INIS)

    Goni, J.

    1984-01-01

    This work is about the water pollution. The air and the water interaction cycles is the main idea of the geochemical pollution conception. In the water surface as well as in the deep aquifers we can found cough metals or minerals from the athmosferic air. The activities of mercury fluor and nitrates are important to the pollution study

  6. Air Pollution.

    Science.gov (United States)

    Barker, K.; And Others

    Pollution of the general environment, which exposes an entire population group for an indeterminate period of time, certainly constitutes a problem in public health. Serious aid pollution episodes have resulted in increased mortality and a possible relationship between chronic exposure to a polluted atmosphere and certain diseases has been…

  7. Selective extraction of bisphenol A from water by one-monomer molecularly imprinted magnetic nanoparticles.

    Science.gov (United States)

    Lin, Zhenkun; Zhang, Yanfang; Su, Yu; Qi, Jinxia; Jia, Yinhang; Huang, Changjiang; Dong, Qiaoxiang

    2018-01-15

    One-monomer molecularly imprinted magnetic nanoparticles were prepared as adsorbents for selective extraction of bisphenol A from water in this study. A single bi-functional monomer was adopted for preparation of the molecularly imprinted polymer, avoiding the tedious trial-and-error optimizations as traditional strategy. Moreover, bisphenol F was used as the dummy template for bisphenol A to avoid the interference from residual template molecules. These nanoparticles showed not only large adsorption capacity and good selectivity to the bisphenol A but also outstanding magnetic response performance. Furthermore, they were successfully used as magnetic solid-phase extraction adsorbents of bisphenol A from various water samples, including tap water, river water, and seawater. The developed method was found to be much more efficient, convenient, and economical for selective extraction of bisphenol A compared with the traditional solid-phase extraction. Separation of these nanoparticles can be easily achieved with an external magnetic field, and the optimized adsorption time was only 15 min. The recoveries of bisphenol A in different water samples ranged from 85.38 to 93.75%, with relative standard deviation lower than 7.47%. These results showed that one-monomer molecularly imprinted magnetic nanoparticles had the potential to be popular adsorbents for selective extraction of pollutants from water. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Polluted Runoff: Nonpoint Source Pollution

    Science.gov (United States)

    Nonpoint Source (NPS) pollution is caused by rainfall or snowmelt moving over and through the ground, it picks up and carries natural and human-made pollutants, depositing them into lakes, rivers, wetlands, coastal waters and ground waters.

  9. (BDMCA) Nanoparticles

    African Journals Online (AJOL)

    Erah

    Available online at http://www.tjpr.org. Research Article ... Methods: Nanoparticle formulations were fabricated by a double emulsion solvent evaporation technique using .... Characterization of BDMCA nanoparticles. The nanoparticle ...

  10. Air pollution

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, W; Mainwaring, S J

    1984-01-01

    This book deals with the nature of air pollution. The numerous sources of unwanted gases and dust particles in the air are discussed. Details are presented of the effects of pollutants on man, animals, vegetation and on inanimate materials. Methods used to measure, monitor and control air pollution are presented. The authors include information on the socio-economic factors which impinge on pollution control and on the problems the future will bring as methods of generating energy change and industries provide new sources of pollutants.

  11. Oil pollution

    International Nuclear Information System (INIS)

    Mankabady, Samir.

    1994-08-01

    Oil enters the marine environment when it is discharged, or has escaped, during transport, drilling, shipping, accidents, dumping and offshore operations. This book serves as a reference both on the various complex international operational and legal matters of oil pollution using examples such as the Exxon Valdez, the Braer and Lord Donaldson's report. The chapters include the development of international rules on the marine environment, the prevention of marine pollution from shipping activities, liability for oil pollution damage, the conflict of the 1990 Oil Pollution Act and the 1992 protocols and finally the cooperation and response to pollution incidents. (UK)

  12. Graphene quantum interference photodetector

    Directory of Open Access Journals (Sweden)

    Mahbub Alam

    2015-03-01

    Full Text Available In this work, a graphene quantum interference (QI photodetector was simulated in two regimes of operation. The structure consists of a graphene nanoribbon, Mach–Zehnder interferometer (MZI, which exhibits a strongly resonant transmission of electrons of specific energies. In the first regime of operation (that of a linear photodetector, low intensity light couples two resonant energy levels, resulting in scattering and differential transmission of current with an external quantum efficiency of up to 5.2%. In the second regime of operation, full current switching is caused by the phase decoherence of the current due to a strong photon flux in one or both of the interferometer arms in the same MZI structure. Graphene QI photodetectors have several distinct advantages: they are of very small size, they do not require p- and n-doped regions, and they exhibit a high external quantum efficiency.

  13. Substation electromagnetic interference

    International Nuclear Information System (INIS)

    Felic, G.; Shihab, S.

    1997-01-01

    The electric and magnetic transients in high voltage substations were studied. The electric field measurements were carried out in a 66 kV switchyard of a 500/220/66 kV substation in Melbourne, Australia. The measured waveforms make up a database to be used for reference in the testing of substation control and protection equipment. The objective of this study was to characterize the radiated interference caused by the operation of disconnect switches and circuit breakers. Disconnect switch transients can be a serious hazard for substations because the slow moving contacts during opening and closing can result in arcing events of several seconds duration. Circuit breaker transients were considered to be less hazardous. Transient magnetic fields of at least several tens of A/m can occur during the energization of the capacitor bank. Substation electronic equipment should be tested and protected against the coupling of these transients in order to avoid breakdowns. 5 refs., 4 figs

  14. Coating magnetic CuFe2O4 nanoparticles with OMS-2 for enhanced degradation of organic pollutants via peroxymonosulfate activation

    Science.gov (United States)

    Ye, Peng; Wu, Deming; Wang, Manye; Wei, Yi; Xu, Aihua; Li, Xiaoxia

    2018-01-01

    A heterogeneous magnetic CuFe2O4@OMS-2 catalyst was fabricated through a facile solvent-free process using Mn(CH3COO)2 and KMnO4 in the presence of CuFe2O4. It was found that the BET surface area of OMS-2 as well as the ratio of low-valent manganese species significantly increased in the hybrid catalyst, due to interactions between CuFe2O4 and the precursor of amorphous manganese oxide. Acid Orange 7 (AO7) and other organic pollutants could be completely degraded by the CuFe2O4@OMS-2 catalyst within 30 min in the presence of peroxymonosulfate (PMS), while CuFe2O4 and OMS-2 showed no significant activity for the reaction. The hybrid catalyst also exhibited excellent long-term stability and could be easily recovered with the assistance of an external magnetic field. A possible degradation mechanism for the synergistic effects of different valent metal species and reactive radicals was proposed, which involved the electron transfer from Mn(III) or Mn(II) species to PMS with the generation of sulfate and hydroxyl radicals, and from AO7 and Cu(I) in CuFe2O4 to Mn(IV) and Mn(III) to reduce these Mn species.

  15. Atmospheric pollution

    International Nuclear Information System (INIS)

    Lambrozo, J.; Guillossou, G.

    2008-01-01

    The atmosphere is the reservoir of numerous pollutants (nitrogen oxides, sulfur oxides, carbon oxides, particulates, volatile organic compounds, polycyclic aromatic hydrocarbons) from natural origin or anthropogenic origin ( industry, transport, agriculture, district heating). With epidemiologic studies the atmospheric pollution is associated with an increase of respiratory and cardiovascular diseases. At the european level, the technological progress, the legislation have allowed a reduction of pollutant emissions, however these efforts have to be continued because the sanitary impact of atmospheric pollution must not be underestimated, even if the risks appear less important that these ones in relation with tobacco, inside pollution or others factors of cardiovascular risks. Indeed, on these last factors an individual action is possible for the exposure to air pollution people have no control. (N.C.)

  16. Surface plasmon resonance enhanced visible-light-driven photocatalytic activity in Cu nanoparticles covered Cu{sub 2}O microspheres for degrading organic pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yahui, E-mail: chengyahui@nankai.edu.cn [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Lin, Yuanjing [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Xu, Jianping [Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384 (China); He, Jie; Wang, Tianzhao; Yu, Guojun; Shao, Dawei; Wang, Wei-Hua; Lu, Feng [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Li, Lan [Institute of Material Physics, Key Laboratory of Display Materials and Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384 (China); Du, Xiwen [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Wang, Weichao [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Liu, Hui, E-mail: liuhui@nankai.edu.cn [Department of Electronics and Key Laboratory of Photo-Electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Zheng, Rongkun [School of Physics, The University of Sydney, Sydney, NSW 2006 (Australia)

    2016-03-15

    Graphical abstract: - Highlights: • Cu NPs introduce the SPR and result in an increase of visible light absorption. • The photocatalytic activity of Cu{sub 2}O/Cu improves greatly due to the SPR effect. • A dark catalytic activity is observed stemming from the Fenton-like reaction. • The • O{sub 2}{sup −} and • OH radicals contribute to the photocatalytic process. • The • OH radicals contribute to the dark catalytic process. - Abstract: Micron-sized Cu{sub 2}O with different coverage of Cu nanoparticles (NPs) on the sphere has been synthesized by a redox procedure. The absorption spectra show that Cu NPs induce the surface plasmon resonance (SPR) at the wavelength of ∼565 nm. Methylene blue (MB) photodegrading experiments under visible-light display that the Cu{sub 2}O–Cu–H{sub 2}O{sub 2} system exhibits a superior photocatalytic activity to Cu{sub 2}O–H{sub 2}O{sub 2} or pure H{sub 2}O{sub 2} with an evident dependency on Cu coverage. The maximum photodegradation rate is 88% after visible-light irradiating for 60 min. The role of the Cu NPs is clarified through photodegradation experiments under 420 nm light irradiation, which is different from the SPR wavelength of Cu NPs (∼565 nm). By excluding the SPR effect, it proves that Cu SPR plays a key role in the photodegradation. Besides, a dark catalytic activity is observed stemming from the Fenton-like reaction with the aid of H{sub 2}O{sub 2}. The radical quenching experiments indicate that both • O{sub 2}{sup −} and • OH radicals contribute to the photocatalysis, while the dark catalysis is only governed by the • OH radicals, leading to a lower activity comparing with the photocatalysis. Therefore, with introducing Cu NPs and H{sub 2}O{sub 2}, the Cu{sub 2}O-based photocatalytic activity could be significantly improved due to the SPR effect and dark catalysis.

  17. Developmental Change in Proactive Interference.

    Science.gov (United States)

    Kail, Robert

    2002-01-01

    Two studies examined age-related change in proactive interference from previously learned material. The meta-analysis of 26 studies indicated that proactive interference decreased with age. The cross-sectional study found that third through sixth graders' and college students' recall was accurate on Trial 1, but became less so over Trials 2…

  18. Sleep can reduce proactive interference.

    Science.gov (United States)

    Abel, Magdalena; Bäuml, Karl-Heinz T

    2014-01-01

    Sleep has repeatedly been connected to processes of memory consolidation. While extensive research indeed documents beneficial effects of sleep on memory, little is yet known about the role of sleep for interference effects in episodic memory. Although two prior studies reported sleep to reduce retroactive interference, no sleep effect has previously been found for proactive interference. Here we applied a study format differing from that employed by the prior studies to induce a high degree of proactive interference, and asked participants to encode a single list or two interfering lists of paired associates via pure study cycles. Testing occurred after 12 hours of diurnal wakefulness or nocturnal sleep. Consistent with the prior work, we found sleep in comparison to wake did not affect memory for the single list, but reduced retroactive interference. In addition we found sleep reduced proactive interference, and reduced retroactive and proactive interference to the same extent. The finding is consistent with the view that arising benefits of sleep are caused by the reactivation of memory contents during sleep, which has been suggested to strengthen and stabilise memories. Such stabilisation may make memories less susceptible to competition from interfering memories at test and thus reduce interference effects.

  19. Output Interference in Recognition Memory

    Science.gov (United States)

    Criss, Amy H.; Malmberg, Kenneth J.; Shiffrin, Richard M.

    2011-01-01

    Dennis and Humphreys (2001) proposed that interference in recognition memory arises solely from the prior contexts of the test word: Interference does not arise from memory traces of other words (from events prior to the study list or on the study list, and regardless of similarity to the test item). We evaluate this model using output…

  20. Interference Phenomenon with Mobile Displays

    Science.gov (United States)

    Trantham, Kenneth

    2015-01-01

    A simple experiment is presented in which the spacing and geometric pattern of pixels in mobile displays is measured. The technique is based on optical constructive interference. While the experiment is another opportunity to demonstrate wave interference from a grating-like structure, this can also be used to demonstrate concepts of solid state…

  1. Environmental pollution

    International Nuclear Information System (INIS)

    Odzuck, W.

    1982-01-01

    The volume of the anthropogenic pollution of the environment (incl. radioactivity) is of great economical importance and has also a meaning to the health and happiness of people. The pocket book introduces into the whole problem by giving exact information and data. After a general survey, the pollutions of urban-industrial, and aquatic ecosystems are dealt with. The book closes with indications as to general principles, specific dangers, and the fature development of the environmental pollution. (orig.) [de

  2. Air pollution

    OpenAIRE

    MacKenbach, JP; Henschel, S; Goodman, P; McKee, M

    2013-01-01

    The human costs of air pollution are considerable in Jordan. According to a report published in 2000 by the World Bank under the Mediterranean Environmental Technical Assistance Program (METAP), approximately 600 people die prematurely each year in Jordan because of urban pollution. 50-90% of air pollution in Jordanian towns is caused by road traffic. Readings taken in 2007 by Jordanian researchers showed that levels of black carbon particles in the air were higher in urban areas (caused by v...

  3. Communications in interference limited networks

    CERN Document Server

    2016-01-01

    This book offers means to handle interference as a central problem of operating wireless networks. It investigates centralized and decentralized methods to avoid and handle interference as well as approaches that resolve interference constructively. The latter type of approach tries to solve the joint detection and estimation problem of several data streams that share a common medium. In fact, an exciting insight into the operation of networks is that it may be beneficial, in terms of an overall throughput, to actively create and manage interference. Thus, when handled properly, "mixing" of data in networks becomes a useful tool of operation rather than the nuisance as which it has been treated traditionally. With the development of mobile, robust, ubiquitous, reliable and instantaneous communication being a driving and enabling factor of an information centric economy, the understanding, mitigation and exploitation of interference in networks must be seen as a centrally important task.

  4. One dimensional CdS nanowire@TiO2 nanoparticles core-shell as high performance photocatalyst for fast degradation of dye pollutants under visible and sunlight irradiation.

    Science.gov (United States)

    Arabzadeh, Abbas; Salimi, Abdollah

    2016-10-01

    In this study, one-dimensional CdS nanowires@TiO2 nanoparticles core-shell structures (1D CdS NWs@TiO2 NPs) were synthesized by a facile wet chemical-solvothermal method. The different aspects of the properties of CdS NWs@TiO2 NPs were surveyed by using a comprehensive range of characterization techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-vis spectroscopy, scanning electron microscopy (SEM), fluorescence spectroscopy, energy dispersive X-ray spectroscopy (EDX), Cyclic Voltammetry (CV) and amperometry. The as-prepared nanostructure was applied as an effective photocatalyst for degradation of methyl orange (MO), methylene blue (MB) and rhodamine B (Rh B) under visible and sunlight irradiation. The results indicated significantly enhanced photocatalytic activity of CdS NWs@TiO2 NPs for degradation of MO, MB and Rh B compared to CdS NWs. The enhanced photocatalytic activity could be attributed to the enhanced sunlight absorbance and the efficient charge separation of the formed heterostructure between CdS NWs and TiO2. The results showed that MO, Rh B and MB were almost completely degraded after 2, 2 and 3min of exposure to sunlight, respectively; while under visible light irradiation (3W blue LED lamp) the dyes were decomposed with less half degradation rate. The catalytic activity was retained even after three degradation cycles of organic dyes, demonstrating that the proposed nanocomposite can be effectively used as efficient photocatalyst for removal of environmental pollutions caused by organic dyes under sunlight irradiation and it could be an important addition to the field of wastewater treatment. We hope the present study may open a new window of such 1-D semiconductor nanocomposites to be used as visible light photocatalysts in the promising field of organic dyes degradation. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Radio Frequency Interference Mitigation

    Science.gov (United States)

    An, T.; Chen, X.; Mohan, P.; Lao, B. Q.

    2017-09-01

    The observational facilities of radio astronomy keep constant upgrades and developments to achieve better capabilities including increasing the time of the data recording and frequency resolutions, and increasing the receiving and recording bandwidth. However in contrast, only a limited spectrum resource has been allocated to radio astronomy by the International Telecommunication Union, resulting in that the radio observational instrumentations are inevitably exposed to undesirable radio frequency interference (RFI) signals which originate mainly from the terrestrial human activity and are becoming stronger with time. RFIs degrade the quality of data and even lead to invalid data. The impact of RFIs on scientific outcome becomes more and more serious. In this article, the requirement for RFI mitigation is motivated, and the RFI characteristics, mitigation techniques, and strategies are reviewed. The mitigation strategies adopted at some representative observatories, telescopes, and arrays are also introduced. The advantages and shortcomings of the four classes of RFI mitigation strategies are discussed and presented, applicable at the connected causal stages: preventive, pre-detection, pre-correlation, and post-correlation. The proper identification and flagging of RFI is the key to the reduction of data loss and improvement in data quality, and is also the ultimate goal of developing RFI mitigation technique. This can be achieved through a strategy involving a combination of the discussed techniques in stages. The recent advances in the high speed digital signal processing and high performance computing allow for performing RFI excision of the large data volumes generated from large telescopes or arrays in both real time and offline modes, aiding the proposed strategy.

  6. Air pollution

    International Nuclear Information System (INIS)

    Anon.

    2008-01-01

    Air pollution has accompanied and developed with the industrial age, since its beginnings. This very complete review furnishes the toxicological data available for the principal pollutants and assesses the epidemiologic studies thus far conducted. It also describes European regulations and international commitments for the reduction of emissions. (author)

  7. Interference management using direct sequence spread spectrum ...

    African Journals Online (AJOL)

    Interference management using direct sequence spread spectrum (DSSS) technique ... Journal of Fundamental and Applied Sciences ... Keywords: DSSS, LTE network; Wi-Fi network; SINR; interference management and interference power.

  8. Optical interference with noncoherent states

    International Nuclear Information System (INIS)

    Sagi, Yoav; Firstenberg, Ofer; Fisher, Amnon; Ron, Amiram

    2003-01-01

    We examine a typical two-source optical interference apparatus consisting of two cavities, a beam splitter, and two detectors. We show that field-field interference occurs even when the cavities are not initially in coherent states but rather in other nonclassical states. However, we find that the visibility of the second-order interference, that is, the expectation values of the detectors' readings, changes from 100%, when the cavities are prepared in coherent states, to zero visibility when they are initially in single Fock states. We calculate the fourth-order interference, and for the latter case find that it corresponds to a case where the currents oscillate with 100% visibility, but with a random phase for every experiment. Finally, we suggest an experimental realization of the apparatus with nonclassical sources

  9. Quantum Erasure: Quantum Interference Revisited

    OpenAIRE

    Walborn, Stephen P.; Cunha, Marcelo O. Terra; Pádua, Sebastião; Monken, Carlos H.

    2005-01-01

    Recent experiments in quantum optics have shed light on the foundations of quantum physics. Quantum erasers - modified quantum interference experiments - show that quantum entanglement is responsible for the complementarity principle.

  10. Toxicity of Engineered Nanoparticles to Aquatic Invertebrates

    DEFF Research Database (Denmark)

    Cupi, Denisa; Sørensen, Sara Nørgaard; Skjolding, Lars Michael

    2016-01-01

    This chapter provides a targeted description of some of the most important processes that influence toxicity and uptake of nanoparticles in aquatic invertebrates. It discusses silver nanoparticles (Ag NPs), on how aspects of dissolution and chemical species obtained from this process can influence...... ecotoxicity of aquatic invertebrates. The chapter focuses on how fullerenes affect the toxicity of other pollutants, but also reflect on the fate and behavior of C60 in the aquatic environment, as well as ecotoxicity to aquatic invertebrates. It presents the case of titanium dioxide nanoparticles (TiO2 NPs...... on bioaccumulation focusing on the effect of nanoparticle coating, uptake, and depuration in aquatic invertebrates....

  11. Interference, reduced action, and trajectories

    OpenAIRE

    Floyd, Edward R.

    2006-01-01

    Instead of investigating the interference between two stationary, rectilinear wave functions in a trajectory representation by examining the two rectilinear wave functions individually, we examine a dichromatic wave function that is synthesized from the two interfering wave functions. The physics of interference is contained in the reduced action for the dichromatic wave function. As this reduced action is a generator of the motion for the dichromatic wave function, it determines the dichroma...

  12. Environmental Pollution

    International Nuclear Information System (INIS)

    Won, Jong IK

    1990-03-01

    This book tells US that what nature is, which gives descriptions of the world of living things like the role of plant, order of the vegetable kingdom, the world of plant, destruction of the natural world, and the world of bugs, nature and human with man's survive and change of nature, environment and human, and in creasing population and environment, philosophy of conservation of nature on meaning, destroy and management, and direction, air pollution spot, water pollution, soil pollution conservation of nature and industry case of foreign country and view of environment and environmental assimilating capacity.

  13. Towards localization of engineered silver nanoparticles in Pseudokirchneriella subcapitata

    DEFF Research Database (Denmark)

    Jensen, Louise Helene Søgaard; Sørensen, Sara Nørgaard; Hartmann, Nanna Isabella Bloch

    Silver nanoparticles have increased cytotoxic properties compared to larger particles. Reflecting these properties, engineered silver nanoparticles are now added to an increasing number of consumer products often labelled as anti-bacterial. These particles are presently considered the fastest...... growing nanotechnology application. Accordingly, silver nanoparticles are now postulated to be released into the sewerage systems and wider environment in increasing quantities. Here they could potentially interfere with aquatic life and this ongoing project aims to localize possible particles taken up...

  14. Importance of layer thermal conductivity on the sharpness of patterns produced by laser interference

    Czech Academy of Sciences Publication Activity Database

    Peláez, R.J.; Afonso, C.N.; Škereň, M.; Bulíř, Jiří

    2016-01-01

    Roč. 374, Jun (2016), s. 61-64 ISSN 0169-4332 Institutional support: RVO:68378271 Keywords : dewetting * laser interference * metal layers * nanoparticles * thermal conductivity Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.387, year: 2016

  15. Ozone Pollution

    Science.gov (United States)

    Known as tropospheric or ground-level ozone, this gas is harmful to human heath and the environment. Since it forms from emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx), these pollutants are regulated under air quality standards.

  16. Water Pollution

    Science.gov (United States)

    ... What is NIEHS Doing? Further Reading For Educators Introduction Water pollution is any contamination of water with ... NIEHS Newsletter) Karletta Chief Featured in Science Friday Film (April 2018) Chlorine Levels Help Detect Risk for ...

  17. Light Pollution

    Science.gov (United States)

    Riegel, Kurt W.

    1973-01-01

    Outdoor lighting is light pollution which handicaps certain astronomical programs. Protective measures must be adopted by the government to aid observational astronomy without sacrificing legitimate outdoor lighting needs. (PS)

  18. Air pollution

    International Nuclear Information System (INIS)

    Nelson, P.

    2000-01-01

    Australian cites experience a number of current and emerging air pollution problems. Concentrations of traditional primary pollutants such as CO, lead and dust have fallen in recent years as a consequence of air pollutant control measures, and the widespread introduction of lead-free petrol. However, recommended guidelines for ozone, the principal component of photochemical smog, are regularly exceeded in major capital cities in the summer months. In addition, it is predicted that extensive urban expansion will lead to much greater dependence on the motor vehicle as the primary means of transportation. Effects of air pollution are felt at a variety of scales. Traditionally, concerns about gaseous and particulate emissions from industrial and vehicular sources were focused on local impacts due to exposure to toxic species such as CO and lead. As noted above, concentrations of these pollutants have been reduced by a variety of control measures. Pollutants which have effects at a regional scale, such as photochemically-produced ozone, and acidic gases and particles have proved more difficult to reduce. In general, these pollutants arc not the result of direct emissions to atmosphere, but result from complex secondary processes driven by photochemical reactions of species such as NO 2 and aldehydes. In addition, global effects of gaseous and particulate emissions to the atmosphere have received significant recent attention, concentrations of atmospheric CO 2 with predicted impacts on global climate, and ozone depletion due to anthropogenic emissions of chlorine-containing chemicals are the two major examples. Combustion processes from petrol- and diesel-fuelled vehicles, make major contributions to air pollution, and the magnitude of this contribution is discussed in this article

  19. Environmental pollution

    International Nuclear Information System (INIS)

    Hanif, J.; Hanif, M.I.

    1997-01-01

    The third proceedings of National Symposium on Modern Trends in Contemporary Chemistry was held in Islamabad, Pakistan from February 24-26, 1997. In this symposium more than 220 scientists, engineers and technologist were registered from 11 universities, 17 research organisations and 8 non-governmental organisation including some commercial establishments. The symposium was divided into five technical sessions on hydro spheric pollution, atmospheric pollution, bio spheric pollution, lithospheric pollution and impact assessment and environmental education. Environmental and ecology are so interdependent that any change in the balance due to natural and man made cause may result in a disaster, flood, fire, earthquake, epidemic, population explosion etc. are the natural ways of unbalancing our ecosystem. The scope of this symposium includes: 1) Review the chemistry and the chemical techniques like polarography, coulometry, HPLC, GC-MS, NAA, XRF, AAS, AES etc. involved in the assessment monitoring and control of various pollutions. 2) Propose sampling, transportation, measurement and standardization procedures. 3) Collaboration in scientific data collection. 4) Mutual consultation for management of the pollution problem in a cost effective manner. 5) sharing knowledge and experience with various environmental protection groups both in public and private sector. (A.B.)

  20. Ground Pollution Science

    International Nuclear Information System (INIS)

    Oh, Jong Min; Bae, Jae Geun

    1997-08-01

    This book deals with ground pollution science and soil science, classification of soil and fundamentals, ground pollution and human, ground pollution and organic matter, ground pollution and city environment, environmental problems of the earth and ground pollution, soil pollution and development of geological features of the ground, ground pollution and landfill of waste, case of measurement of ground pollution.

  1. Numerical study on flow and pollutant dispersion inside street canyons

    OpenAIRE

    Yunkai, Yang

    2013-01-01

    This thesis analyzes the characteristics of flow pattern and vehicle-emitted pollutant dispersion in roughness surface layer. In an urban environment, wind flow and transported-pollutant source interfere strongly with buildings and other roughness elements on the surface ground, which results in complex characteristics of flow pattern and pollutant dispersion in 3D circumstances. The present study intends to simplify the research domain and investigate the fundamental modeling problems that e...

  2. Interference in motor learning - is motor interference sensory?

    DEFF Research Database (Denmark)

    Jensen, Jesper Lundbye; Petersen, Tue Hvass; Rothwell, John C

    mechanisms determine whether or not interference occurs. We hypothesised that interference requires the same neural circuits to be engaged in the two tasks and provoke competing processes of synaptic plasticity. To test this, subjects learned a ballistic ankle plantarflexion task. Early motor memory...... was disrupted by subsequent learning of a precision tracking task with the same agonist muscle group, but not by learning involving antagonist muscles or by voluntary agonist contractions that did not require learning. If the competing task was learned with the same agonist muscle group 4 hours following...

  3. WEED INTERFERENCE IN EGGPLANT CROPS

    Directory of Open Access Journals (Sweden)

    LUIZ JUNIOR PEREIRA MARQUES

    2017-01-01

    Full Text Available Uncontrolled weed growth interferes with the growth eggplants and crop yields. To control weeds, the main weed species must be identified in crop growing areas and during weed control periods, as weed species might vary in relation to management practices. Therefore, this study aimed to identify the main weed species and determine the periods of weed interference in the eggplant cultivar Nápoli when grown under certain cultural practices, including plant staking and sprout thinning. The experiment was carried out in 2014 using a randomized complete block design, with 3 replications. The treatments consisted of 11 periods of (1 increasing weed control and (2 increasing coexistence of eggplant with weeds from the first day of transplanting (0-14, 0-28, 0-42, 0-56, 0-70, 0-84, 0-98, 0-112, 0-126, 0-140, and up do day 154. Eggplant staking and sprout thinning were performed 42 days after transplanting (DAT. Weed identification and crop yield assessments were performed to determine the Period Before Interference (PBI, Total Period of Interference Prevention (TPIP, and the Critical Period of Interference Prevention (CPIP. The major weeds found in the eggplant cultivar Nápoli were Eleusine indica, Portulaca oleracea, and Cyperus rotundus. Coexistence between the weed community and the eggplant throughout the entire crop production cycle reduced eggplant fruit yield by 78%. The PBI was 29 DAT and the TPIP was 48 DAT, resulting in 19 days of CPIP.

  4. Detection of magnetic nanoparticles with magnetoencephalography

    Energy Technology Data Exchange (ETDEWEB)

    Jia Wenyan [Department of Neurosurgery, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Xu, Guizhi [Department of Neurosurgery, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Department of Biomedical Engineering, Hebei University of Technology, Tianjin, 300130 (China); Sclabassi, Robert J. [Department of Neurosurgery, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Zhu Jiangang [Department of Electrical and Computer Engineering, Carnegie Melon University, Pittsburgh, PA 15213 (United States); Bagic, Anto [Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Sun Mingui [Department of Neurosurgery, University of Pittsburgh, Pittsburgh, PA 15260 (United States)], E-mail: mrsun@neuronet.pitt.edu

    2008-04-15

    Superconducting quantum interference devices (SQUIDs) have been widely utilized in biomedical applications due to their extremely high sensitivity to magnetic signals. The present study explores the feasibility of a new type of nanotechnology-based imaging method using standard clinical magnetoencephalographic (MEG) systems equipped with SQUID sensors. Previous studies have shown that biological targets labeled with non-toxic, magnetized nanoparticles can be imaged by measuring the magnetic field generated by these particles. In this work, we demonstrate that (1) the magnetic signals from certain nanoparticles can be detected without magnetization using standard clinical MEG, (2) for some types of nanoparticles, only bound particles produce detectable signals, and (3) the magnetic field of particles several hours after magnetization is significantly stronger than that of un-magnetized particles. These findings hold promise in facilitating the potential application of magnetic nanoparticles to in vivo tumor imaging. The minimum amount of nanoparticles that produce detectable signals is predicted by theoretical modeling and computer simulation.

  5. Interference in ballistic motor learning - is motor interference really sensory?

    DEFF Research Database (Denmark)

    Lundbye-Jensen, Jesper; Petersen, Tue Hvass; Rothwell, John C

    Skill gained after a short period of practice in one motor task can be abolished if a second task is learned shortly afterwards. We hypothesised that interference requires the same circuits to be engaged in the two tasks and provoke competing processes of synaptic plasticity. To test this, subjects...

  6. 'Quantum interference with slits' revisited

    Science.gov (United States)

    Rothman, Tony; Boughn, Stephen

    2011-01-01

    Marcella has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his calculation as if no approximations are employed. We show that he implicitly makes the same approximations found in classical treatments of interference and that no new physics has been introduced. At the same time, some of the quantum mechanical arguments Marcella gives are, at best, misleading.

  7. Parton showers with quantum interference

    CERN Document Server

    Nagy, Zoltan

    2007-01-01

    We specify recursive equations that could be used to generate a lowest order parton shower for hard scattering in hadron-hadron collisions. The formalism is based on the factorization soft and collinear interactions from relatively harder interactions in QCD amplitudes. It incorporates quantum interference between different amplitudes in those cases in which the interference diagrams have leading soft or collinear singularities. It incorporates the color and spin information carried by partons emerging from a hard interaction. One motivation for this work is to have a method that can naturally cooperate with next-to-leading order calculations.

  8. Parton showers with quantum interference

    International Nuclear Information System (INIS)

    Nagy, Zoltan; Soper, Davison E.

    2007-01-01

    We specify recursive equations that could be used to generate a lowest order parton shower for hard scattering in hadron-hadron collisions. The formalism is based on the factorization soft and collinear interactions from relatively harder interactions in QCD amplitudes. It incorporates quantum interference between different amplitudes in those cases in which the interference diagrams have leading soft or collinear singularities. It incorporates the color and spin information carried by partons emerging from a hard interaction. One motivation for this work is to have a method that can naturally cooperate with next-to-leading order calculations

  9. Magnetic properties of iron nanoparticle

    International Nuclear Information System (INIS)

    Carvell, J.; Ayieta, E.; Gavrin, A.; Cheng, Ruihua; Shah, V. R.; Sokol, P.

    2010-01-01

    Magnetic properties of Fe nanoparticles with different sizes synthesized by a physical deposition technique have been investigated experimentally. We have used a high pressure sputtering technique to deposit iron nanoparticles on a silicon substrate. The nanoparticles are then analyzed using atomic force microscopy (AFM), transmission electron microscopy (TEM), and superconducting quantum interference device techniques. TEM and AFM data show that the particle size could be tuned by adjusting the deposition conditions. The magnetic properties have been investigated from temperature dependent magnetization M(T) and field dependent magnetization M(H) measurements. The results show that two phases including both ferromagnetic and superparamagnetic particles are present in our system. From these data we extracted the superparamagnetic critical size to be 9 nm for our samples. Ferromagnetic particles are single magnetic domain particles and the magnetic properties can be explained by the Stoner and Wohlfarth model. For the superparamagnetic phase, the effective anisotropy constant, K eff , decreases as the particle size increases.

  10. Air pollution

    International Nuclear Information System (INIS)

    Feugier, A.

    1996-01-01

    The air pollution results from the combustion of petroleum products, natural gas, coal, wastes and transports. Some compounds are considered as particularly pollutants: the carbon monoxide, the nitrogen oxides, the tropospheric ozone and the sulfur dioxides. Their environmental and biological effects are described. The present political guide lines concerns the combustion plants, the ozone, the wastes incineration and the vehicles emissions. The aim is at some future date to control the air quality, to reduce the volatile organic compounds emissions and to limit the sulfur rate of some petroleum products. (O.L.)

  11. ENVIRONMENTAL POLLUTION

    OpenAIRE

    Reyna Ramos, julio

    2014-01-01

    The article shows the complexity of the problem of environmental pollution and what can be the possible solutions to the problem. Also, how the Industrial Engineering can contribute to the prevention and control of pollution. El artículo muestra la complejidad del problema de la contaminación ambiental y cuáles pueden ser las propuestas de solución al problema. Así mismo, cómo la Ingeniería Industrial puede contribuir a la prevención y control de la contaminación.

  12. Ground water pollution through air pollutants

    International Nuclear Information System (INIS)

    Cichorowski, G.; Michel, B.; Versteegen, D.; Wettmann, R.

    1989-01-01

    The aim of the investigation is to determine the significance of air pollutants for ground water quality and ground water use. The report summarizes present knowledge and assesses statements with a view to potential ground water pollution from the air. In this context pollution paths, the spreading behaviour of pollutants, and 'cross points' with burden potentials from other pollutant sources are presented. (orig.) [de

  13. Conducted interference on smart meters

    NARCIS (Netherlands)

    Keyer, Cornelis H.A.; Leferink, Frank

    2017-01-01

    The increasing conducted interference caused by modern electronic equipment is causing more problems for electronic, or static, energy meters. These meters are called smart meters when equipped with a communication link, and are replacing the conventional electromechanical meters. It is known that

  14. Electromagnetic Interference in Smart Grids

    NARCIS (Netherlands)

    Leferink, Frank; Keyer, Cees

    2017-01-01

    The increasing conducted interference caused by modern electronic equipment is causing more problems for electronic, or static, energy meters. If equipped with a communication link they are called smart meter. Because the smart meter is a key device in smart grids, any deviation has huge impact on

  15. "Quantum Interference with Slits" Revisited

    Science.gov (United States)

    Rothman, Tony; Boughn, Stephen

    2011-01-01

    Marcella has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his…

  16. Interference and memory capacity limitations.

    Science.gov (United States)

    Endress, Ansgar D; Szabó, Szilárd

    2017-10-01

    Working memory (WM) is thought to have a fixed and limited capacity. However, the origins of these capacity limitations are debated, and generally attributed to active, attentional processes. Here, we show that the existence of interference among items in memory mathematically guarantees fixed and limited capacity limits under very general conditions, irrespective of any processing assumptions. Assuming that interference (a) increases with the number of interfering items and (b) brings memory performance to chance levels for large numbers of interfering items, capacity limits are a simple function of the relative influence of memorization and interference. In contrast, we show that time-based memory limitations do not lead to fixed memory capacity limitations that are independent of the timing properties of an experiment. We show that interference can mimic both slot-like and continuous resource-like memory limitations, suggesting that these types of memory performance might not be as different as commonly believed. We speculate that slot-like WM limitations might arise from crowding-like phenomena in memory when participants have to retrieve items. Further, based on earlier research on parallel attention and enumeration, we suggest that crowding-like phenomena might be a common reason for the 3 major cognitive capacity limitations. As suggested by Miller (1956) and Cowan (2001), these capacity limitations might arise because of a common reason, even though they likely rely on distinct processes. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  17. Nuclear pollution

    International Nuclear Information System (INIS)

    Ramade, Francois

    1979-01-01

    In this chapter devoted to nuclear pollution the following topics were studied: fundamentals of radiobiology (ecological importance of the various radioisotopes, biological effects of ionizing radiations); ecological effects of radioactive fallout (contamination of atmosphere, terrestrial ecosystems, oceans). The electronuclear industry and its environmental impact. PWR type reactors, fuel reprocessing plants, contamination of trophic chains by radionuclides released in the environment from nuclear installations [fr

  18. Water Pollution

    Science.gov (United States)

    We all need clean water. People need it to grow crops and to operate factories, and for drinking and recreation. Fish and wildlife depend on ... and phosphorus make algae grow and can turn water green. Bacteria, often from sewage spills, can pollute ...

  19. Rapid doubling of Alzheimer’s amyloid-β40 and 42 levels in brains of mice exposed to a nickel nanoparticle model of air pollution [v1; ref status: indexed, http://f1000r.es/T5Rxeo

    Directory of Open Access Journals (Sweden)

    Soong Ho Kim

    2012-12-01

    Full Text Available Background: Over 20 genetic risk factors have been confirmed to associate with elevated risk for Alzheimer’s disease (AD, but the identification of environmental and/or acquired risk factors has been more elusive. At present, recognized acquired risks for AD include traumatic brain injury, hypercholesterolemia, obesity, hypertension, and type 2 diabetes. Methods: Based on reports associating various inhalants with AD pathology, we investigated the possibility that air pollution might contribute to AD risk by exposing wild-type mice to a standard air pollution modeling system employing nickel nanoparticle-enriched atmosphere for 3 hr. Results: Mice exposed to air pollution showed 72-129% increases in brain levels of both amyloid-β peptides Aβ40 and Aβ42, as well as Aβ42/40 (p <0.01. Conclusions: These effects on elevation of brain Aβ exceed those associated with trisomy 21, a known risk for early onset AD pathology, raising the possibility that clinical importance might be attached. Further work is required to establish the molecular and physiological basis for these phenomena. The rapid, dramatic effect, if verified, would suggest that inhalant exposures should be evaluated for their possible roles in contributing to the environmental risk for common forms of AD.

  20. Fouling behavior during microfiltration of silica nanoparticles and polymeric stabilizers

    NARCIS (Netherlands)

    Trzaskus, Krzystof; Zdeb, Aneta; de Vos, Wiebe Matthijs; Kemperman, Antonius J.B.; Nijmeijer, Dorothea C.

    2016-01-01

    Nanotechnology applications give rise to new forms of water pollution, resulting in a need for reliable technologies that can remove nanoparticles from water. Membrane filtration is an obvious candidate. The tendency of nanoparticles to become instable in suspension and form aggregates strongly

  1. Silver nanoparticles – a material of the future…?

    Directory of Open Access Journals (Sweden)

    Pulit-Prociak Jolanta

    2016-01-01

    Full Text Available The paper presents properties of nanomaterials and methods of their principal applications. Environmental aspects of using nanomaterials and reasons for their toxicity are also reviewed. The vast part of the paper is devoted to properties, application and market of silver nanoparticles. Their biocidal activity is clarified. However, silver nanoparticles may cause environmental pollution. Reasons for their toxicity have been also described.

  2. The Internet Pollution

    Institute of Scientific and Technical Information of China (English)

    唐宁宁

    2005-01-01

    Life today has brought new problems. As we know, there are fourterrible pollutions in the world: water pollution, noise pollution, air pol-lution and rubbish pollution. Water pollution kills our fish and pollutesour drinking water. Noise pollution makes us talk louder and become angry more easily. Air pollution makes us hold our breath longer and be badto all living things in the world. Rubbish pollution often makes our livingenvironment much dirtier. But I think that the Internet pollution is anothernew pollution in the world.

  3. REM sleep rescues learning from interference

    Science.gov (United States)

    McDevitt, Elizabeth A.; Duggan, Katherine A.; Mednick, Sara C.

    2015-01-01

    Classical human memory studies investigating the acquisition of temporally-linked events have found that the memories for two events will interfere with each other and cause forgetting (i.e., interference; Wixted, 2004). Importantly, sleep helps consolidate memories and protect them from subsequent interference (Ellenbogen, Hulbert, Stickgold, Dinges, & Thompson-Schill, 2006). We asked whether sleep can also repair memories that have already been damaged by interference. Using a perceptual learning paradigm, we induced interference either before or after a consolidation period. We varied brain states during consolidation by comparing active wake, quiet wake, and naps with either non-rapid eye movement sleep (NREM), or both NREM and REM sleep. When interference occurred after consolidation, sleep and wake both produced learning. However, interference prior to consolidation impaired memory, with retroactive interference showing more disruption than proactive interference. Sleep rescued learning damaged by interference. Critically, only naps that contained REM sleep were able to rescue learning that was highly disrupted by retroactive interference. Furthermore, the magnitude of rescued learning was correlated with the amount of REM sleep. We demonstrate the first evidence of a process by which the brain can rescue and consolidate memories damaged by interference, and that this process requires REM sleep. We explain these results within a theoretical model that considers how interference during encoding interacts with consolidation processes to predict which memories are retained or lost. PMID:25498222

  4. Pollution law

    International Nuclear Information System (INIS)

    Triffterer, O.

    1980-01-01

    In the draft proposed by the legal advisory board the law for the controlling of environmental criminality was promulgated on 28th March 1980. The present commentary therefore - as seen from the results - corresponds in essential to the original assessment of the governmental draft. However, an introduction into the problems of environmental law precedes this commentary for the better unterstanding of all those not acquainted with pollution law and the whole legal matter. (orig./HP) [de

  5. Radioactive pollution

    International Nuclear Information System (INIS)

    Steiner, R.

    1987-01-01

    In the wake of the Chernobyl reactor accident on April 26, 1986, many individual values for radioactivity in the air, in foodstuffs and in the soil were measured and published. Prof. Dr. Rolf Steiner, Wiesbaden, the author of this paper, evaluated the host of data - mostly official pollution data -, drew conclusions regarding the radioactivity actually released at Chernobyl, and used the data to test the calculation model adotped by the Radiation Protection Ordinance. (orig./RB) [de

  6. Interference Lithography for Vertical Photovoltaics

    Science.gov (United States)

    Balls, Amy; Pei, Lei; Kvavle, Joshua; Sieler, Andrew; Schultz, Stephen; Linford, Matthew; Vanfleet, Richard; Davis, Robert

    2009-10-01

    We are exploring low cost approaches for fabricating three dimensional nanoscale structures. These vertical structures could significantly improve the efficiency of devices made from low cost photovoltaic materials. The nanoscale vertical structure provides a way to increase optical absorption in thin photovoltaic films without increasing the electronic carrier separation distance. The target structure is a high temperature transparent template with a dense array of holes on a 400 - 600 nm pitch fabricated by a combination of interference lithography and nanoembossing. First a master was fabricated using ultraviolet light interference lithography and the pattern was transferred into a silicon wafer master by silicon reactive ion etching. Embossing studies were performed with the master on several high temperature polymers.

  7. Image hiding using optical interference

    Science.gov (United States)

    Zhang, Yan; Wang, Weining

    2010-09-01

    Optical image encryption technology has attracted a lot of attentions due to its large capacitance and fast speed. In conventional image encryption methods, the random phase masks are used as encryption keys to encode the images into white noise distribution. Therefore, this kind of methods requires interference technology to record complex amplitude and is vulnerable to attack techniques. The image hiding methods which employ the phase retrieve algorithm to encode the images into two or more phase masks are proposed, the hiding process is carried out within a computer using iterative algorithm. But the iterative algorithms are time consumed. All method mentioned above are based on the optical diffraction of the phase masks. In this presentation, a new optical image hiding method based on optical interference is proposed. The coherence lights which pass through two phase masks are combined by a beam splitter. Two beams interfere with each other and the desired image appears at the pre-designed plane. Two phase distribution masks are design analytically; therefore, the hiding speed can be obviously improved. Simulation results are carried out to demonstrate the novelty of the new proposed methods. This method can be expanded for double images hiding.

  8. Quantum interference in plasmonic circuits.

    Science.gov (United States)

    Heeres, Reinier W; Kouwenhoven, Leo P; Zwiller, Valery

    2013-10-01

    Surface plasmon polaritons (plasmons) are a combination of light and a collective oscillation of the free electron plasma at metal/dielectric interfaces. This interaction allows subwavelength confinement of light beyond the diffraction limit inherent to dielectric structures. As a result, the intensity of the electromagnetic field is enhanced, with the possibility to increase the strength of the optical interactions between waveguides, light sources and detectors. Plasmons maintain non-classical photon statistics and preserve entanglement upon transmission through thin, patterned metallic films or weakly confining waveguides. For quantum applications, it is essential that plasmons behave as indistinguishable quantum particles. Here we report on a quantum interference experiment in a nanoscale plasmonic circuit consisting of an on-chip plasmon beamsplitter with integrated superconducting single-photon detectors to allow efficient single plasmon detection. We demonstrate a quantum-mechanical interaction between pairs of indistinguishable surface plasmons by observing Hong-Ou-Mandel (HOM) interference, a hallmark non-classical interference effect that is the basis of linear optics-based quantum computation. Our work shows that it is feasible to shrink quantum optical experiments to the nanoscale and offers a promising route towards subwavelength quantum optical networks.

  9. Water Pollution. Project COMPSEP.

    Science.gov (United States)

    Lantz, H. B., Jr.

    This is an introductory program on water pollution. Examined are the cause and effect relationships of water pollution, sources of water pollution, and possible alternatives to effect solutions from our water pollution problems. Included is background information on water pollution, a glossary of pollution terminology, a script for a slide script…

  10. Carbon nanostructure composite for electromagnetic interference

    Indian Academy of Sciences (India)

    2015-05-30

    based composite materials for electromagnetic interference (EMI) shielding. With more and more electronic gadgets being used at different frequencies, there is a need for shielding them from one another to avoid interference.

  11. Laser induced synthesis of nanoparticles in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Kazakevich, P.V. [Wave Research Center, General Physics Institute of the Russian Academy of Sciences, 38 Vavilov street, 117942 Moscow (Russian Federation); Simakin, A.V. [Wave Research Center, General Physics Institute of the Russian Academy of Sciences, 38 Vavilov street, 117942 Moscow (Russian Federation); Voronov, V.V. [Wave Research Center, General Physics Institute of the Russian Academy of Sciences, 38 Vavilov street, 117942 Moscow (Russian Federation); Shafeev, G.A. [Wave Research Center, General Physics Institute of the Russian Academy of Sciences, 38 Vavilov street, 117942 Moscow (Russian Federation)]. E-mail: shafeev@kapella.gpi.ru

    2006-04-30

    The review of results on nanoparticles formation is presented under laser ablation of Ag, Au, and Cu-containing solid targets in liquid environments (H{sub 2}O, C{sub 2}H{sub 5}OH, C{sub 2}H{sub 4}Cl{sub 2}, etc.). X-ray diffractometry (XRD), UV-vis optical transmission spectrometry, and high resolution transmission electron microscopy (HRTEM) characterize the nanoparticles. The morphology of nanoparticles is studied as the function of both laser fluence and nature of the liquid. The possibility to control the shape of nanoparticles by ablation of an Au target by an interference pattern of two laser beams is demonstrated. Formation of alloyed Au-Ag and Ag-Cu nanoparticles is reported under laser exposure of a mixture of individual nanoparticles. The effect of internal segregation of brass nanoparticles is discussed due to their small lateral dimensions. The factors are discussed that determine the distribution function of particles size under laser ablation. The influence of laser parameters as well as the nature on the liquid on the properties of nanoparticles is elucidated.

  12. SERS substrates fabricated using ceramic filters for the detection of bacteria: Eliminating the citrate interference

    Science.gov (United States)

    Mosier-Boss, P. A.; Sorensen, K. C.; George, R. D.; Sims, P. C.; O'braztsova, A.

    2017-06-01

    It was found that spectra obtained for bacteria on SERS substrates fabricated by filtering citrate-generated Ag nanoparticles (NPs) onto rigid, ceramic filters exhibited peaks due to citrate as well as the bacteria. In many cases the citrate spectrum overwhelmed that of the bacteria. Given the simplicity of the method to prepare these substrates, means of eliminating this citrate interference were explored. It was found that allowing a mixture of bacteria suspension and citrate-generated Ag NPs to incubate prior to filtering onto the ceramic filter eliminated this interference.

  13. (BDMCA) Nanoparticles

    African Journals Online (AJOL)

    Methods: Nanoparticle formulations were fabricated by a double emulsion solvent evaporation technique using polycaprolactone as the polymer. The nanoparticles were characterised for drug content, particles size, in vitro drug release and the drug-polymer interaction. The in vivo properties of the formulations in male ...

  14. Quantum eraser for three-slit interference

    Indian Academy of Sciences (India)

    Naveed Ahmad Shah

    2017-11-09

    Nov 9, 2017 ... Abstract. It is well known that in a two-slit interference experiment, if the information, on which of the two paths the particle followed, is stored in a quantum path detector, the interference is destroyed. However, in a set-up where this path information is 'erased', the interference can reappear. Such a set-up is ...

  15. An accumulator model of semantic interference

    NARCIS (Netherlands)

    van Maanen, Leendert; van Rijn, Hedderik

    To explain latency effects in picture-word interference tasks, cognitive models need to account for both interference and stimulus onset asynchrony (SOA) effects. As opposed to most models of picture-word interference, which model the time course during the task in a ballistic manner, the RACE model

  16. 47 CFR 27.1221 - Interference protection.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Interference protection. 27.1221 Section 27... Technical Standards § 27.1221 Interference protection. (a) Interference protection will be afforded to BRS... height benchmark (hbm). (c) Protection for Receiving Antennas not Exceeding the Height Benchmark. Absent...

  17. Intermetallic nanoparticles

    Science.gov (United States)

    Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules

    2015-07-14

    A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

  18. Radioactive pollution

    International Nuclear Information System (INIS)

    Pohl, R.O.

    1976-01-01

    The widely published claims that the public health effects resulting from routine emissions are between 0.01 and 0.1 serious health effects per gigawattyear, and hence are at least a thousand times smaller than those resulting from air pollution by the burning of coal, cannot be true, for two reasons. The authors of these claims have ignored at least two of the more important isotopes, radon-222 and carbon-14, which are presently released to the environment, and thus contribute greatly to the health impact of nuclear energy. The health effects calculated in the earlier work cover only those which occur during the year in which the energy is generated. This means, figuratively speaking, that the authors have confused an annual installment payment with the full cost. This is unacceptable. The contribution to the health impact of nuclear energy arising from the single isotopic species radon-222 emanating from the mill tailings is estimated to 400 lung cancer deaths/GW(e)y, larger even than the most pessimistic estimates of the health impact of energy from coal through atmospheric pollution. We have no assurance that other long-lived isotopes do not contribute comparable amounts to the health impact of nuclear energy. The discussion of the health impact of radon-222 raises the fundamental moral question--how far into the future our responsibility extends. If such a long-termresponsibility is rejected, then we must at least try to predict the environmental buildup of radioactive pollutants, in order to avoid unacceptable and irreversible levels of radiation dose rate. The potential health consequences from long-lived radioisotopes seem to have been largely ignored so far, and should be explored in detail

  19. Indoor Air Pollution (Environmental Health Student Portal)

    Science.gov (United States)

    ... Students to Environmental Health Information Menu Home Air Pollution Air Pollution Home Indoor Air Pollution Outdoor Air Pollution ... Pollution Indoor Air Pollution Print this Page Air Pollution Air Pollution Home Indoor Air Pollution Outdoor Air Pollution ...

  20. Codebook-based interference alignment for uplink MIMO interference channels

    KAUST Repository

    Lee, Hyun Ho

    2014-02-01

    In this paper, we propose a codebook-based interference alignment (IA) scheme in the constant multiple-input multipleoutput (MIMO) interference channel especially for the uplink scenario. In our proposed scheme, we assume cooperation among base stations (BSs) through reliable backhaul links so that global channel knowledge is available for all BSs, which enables BS to compute the transmit precoder and inform its quantized index to the associated user via limited rate feedback link.We present an upper bound on the rate loss of the proposed scheme and derive the scaling law of the feedback load tomaintain a constant rate loss relative to IA with perfect channel knowledge. Considering the impact of overhead due to training, cooperation, and feedback, we address the effective degrees of freedom (DOF) of the proposed scheme and derive the maximization of the effective DOF. From simulation results, we verify our analysis on the scaling law to preserve the multiplexing gain and confirm that the proposed scheme is more effective than the conventional IA scheme in terms of the effective DOF. © 2014 KICS.

  1. Quantum Interference and Coherence Theory and Experiments

    CERN Document Server

    Ficek, Zbigniew; Rhodes, William T; Asakura, Toshimitsu; Brenner, Karl-Heinz; Hänsch, Theodor W; Kamiya, Takeshi; Krausz, Ferenc; Monemar, Bo; Venghaus, Herbert; Weber, Horst; Weinfurter, Harald

    2005-01-01

    For the first time, this book assembles in a single volume accounts of many phenomena involving quantum interference in optical fields and atomic systems. It provides detailed theoretical treatments and experimental analyses of such phenomena as quantum erasure, quantum lithography, multi-atom entanglement, quantum beats, control of decoherence, phase control of quantum interference, coherent population trapping, electromagnetically induced transparency and absorption, lasing without inversion, subluminal and superluminal light propagation, storage of photons, quantum interference in phase space, interference and diffraction of cold atoms, and interference between Bose-Einstein condensates. This book fills a gap in the literature and will be useful to both experimentalists and theoreticians.

  2. INTERFERENCE OF UNIDIRECTIONAL SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-05-01

    Full Text Available Subject of study.We consider interference of unidirectional shock waves or, as they are called, catching up shock waves. The scope of work is to give a classification of the shock-wave structures that arise in this type of interaction of shock waves, and the area of their existence. Intersection of unidirectional shock waves results in arising of a shock-wave structure at the intersection point, which contains the main shock wave, tangential discontinuity and one more reflected gas-dynamic discontinuity of unknown beforehand type. The problem of determining the type of reflected discontinuity is the main problem that one has to solve in the study of catching shock waves interference. Main results.The paper presents the pictures of shock-wave structures arising at the interaction of catching up shock waves. The areas with a regular and irregular unidirectional interaction of shocks are described. Characteristic shock-wave structures are of greatest interest, where reflected gas-dynamic discontinuity degenerates into discontinuous characteristics. Such structures have a number of extreme properties. We have found the areas of existence for such shock-wave structures. There are also areas in which the steady-state solution is not available. The latter has determined revival of interest for the theoretical study of the problem, because the facts of sudden shock-wave structure destruction inside the air intake of supersonic aircrafts at high Mach numbers have been discovered. Practical significance.The theory of interference for unidirectional shock waves and design procedure are usable in the design of supersonic air intakes. It is also relevant for application possibility investigation of catching up oblique shock waves to create overcompressed detonation in perspective detonation air-jet and rocket engines.

  3. Embracing interference in wireless systems

    CERN Document Server

    Gollakota, Shyamnath

    2014-01-01

    The wireless medium is a shared resource. If nearby devices transmit at thesame time, their signals interfere, resulting in a collision. In traditionalnetworks, collisions cause the loss of the transmitted information. For thisreason, wireless networks have been designed with the assumption thatinterference is intrinsically harmful and must be avoided.This book, a revised version of the author's award-winning Ph.D.dissertation, takes an alternate approach: Instead of viewing interferenceas an inherently counterproductive phenomenon that should to be avoided, wedesign practical systems that tra

  4. Interference Mitigation in Cognitive Femtocells

    DEFF Research Database (Denmark)

    Da Costa, Gustavo Wagner Oliveira; Cattoni, Andrea Fabio; Alvarez Roig, Victor

    2010-01-01

    , management and optimization can be prohibitive. Instead, self-optimization of an uncoordinated deployment should be considered. Cognitive Radio enabled femtocells are considered to be a promising solution to enable self-optimizing femtocells to effectively manage the inter-cell interference, especially...... in densely deployed femto scenarios. In this paper, two key elements of cognitive femtocells are combined: a power control algorithm and a fully distributed dynamic spectrum allocation method. The resulting solution was evaluated through system-level simulations and compared to the separate algorithms...

  5. Synthesis and characterization of dextran-coated iron oxide nanoparticles

    Science.gov (United States)

    Predescu, Andra Mihaela; Matei, Ecaterina; Berbecaru, Andrei Constantin; Pantilimon, Cristian; Drăgan, Claudia; Vidu, Ruxandra; Predescu, Cristian; Kuncser, Victor

    2018-03-01

    Synthesis and characterization of iron oxide nanoparticles coated with a large molar weight dextran for environmental applications are reported. The first experiments involved the synthesis of iron oxide nanoparticles which were coated with dextran at different concentrations. The synthesis was performed by a co-precipitation technique, while the coating of iron oxide nanoparticles was carried out in solution. The obtained nanoparticles were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction spectrometry, Fourier transform infrared spectroscopy and superconducting quantum interference device magnetometry. The results demonstrated a successful coating of iron oxide nanoparticles with large molar weight dextran, of which agglomeration tendency depended on the amount of dextran in the coating solution. SEM and TEM observations have shown that the iron oxide nanoparticles are of about 7 nm in size.

  6. Coping with Indoor Air Pollution

    Science.gov (United States)

    ... Pollution > Coping with Indoor Air Pollution Font: Outdoor Pollution Indoor Air Pollution Asthma Triggers For Kids and Teachers Coping with Indoor Air Pollution Indoor air pollution is irritating to everyone: But people who ...

  7. Reciprocal upregulation of scavenger receptors complicates interpretation of nanoparticle uptake in non-phagocytic cells

    NARCIS (Netherlands)

    Prapainop, Kanlaya; Miao, Rong; Åberg, Christoffer; Salvati, Anna; Dawson, Kenneth A

    2017-01-01

    Nanoparticles have great potential as drug delivery vehicles or as imaging agents for treatment and diagnosis of various diseases. It is therefore crucial to understand how nanoparticles are taken up by cells, both phagocytic and non-phagocytic. Small interference RNA has previously been used to

  8. Environmental Pollution: Noise Pollution - Sonic Boom

    Science.gov (United States)

    1977-06-01

    UNCLASSIFIED AD-A041 400 DDC/BIB-77/06 ENVIRONMENTAL POLLUTION NOISE POLLUTION SONIC BOOM A DDC BIBLIOGRAPHY DDC-TAS Cameron Station Alexandria, Va...rn7Sttio 658S-A041 400 4 TITLE xand r.VuhtlVlia) 2 TA i b- 1iblog ra ph y ENVIRONMENTAL POLLUTION : --. Apr-l IM59-Jul, 7NOISE POLLUTION -SONIC BOOM. 1,976...BIBLIOGRAPHY SEARCH CONTROL NO. /2OM09 AD- 769 970 20/1 1/3 DEFENSE UOCUMENTATION CENTER ALEXANDRIA VA ENVIRONMENTAL POLLUTION : NOISE POLLUTION

  9. (shell) nanoparticles

    Indian Academy of Sciences (India)

    the quasistatic approximation shows good agreement with the Mie theory results. .... medium, respectively, and f = (rcore/rshell)1/3 is the fraction of the total particle ..... [27] Michael Quinten, Optical properties of nanoparticle systems: Mie and ...

  10. Perspectives for quantum interference with biomolecules and biomolecular clusters

    International Nuclear Information System (INIS)

    Geyer, P; Sezer, U; Rodewald, J; Mairhofer, L; Dörre, N; Haslinger, P; Eibenberger, S; Brand, C; Arndt, M

    2016-01-01

    Modern quantum optics encompasses a wide field of phenomena that are either related to the discrete quantum nature of light, the quantum wave nature of matter or light–matter interactions. We here discuss new perspectives for quantum optics with biological nanoparticles. We focus in particular on the prospects of matter-wave interferometry with amino acids, nucleotides, polypeptides or DNA strands. We motivate the challenge of preparing these objects in a ‘biomimetic’ environment and argue that hydrated molecular beam sources are promising tools for quantum-assisted metrology. The method exploits the high sensitivity of matter-wave interference fringes to dephasing and shifts in the presence of external perturbations to access and determine molecular properties. (invited comment)

  11. Light Pollution and Wildlife

    Science.gov (United States)

    Duffek, J.

    2008-12-01

    for Educational Program IYA Dark Skies Education Session Fall American Geophysical Union San Francisco, December 15-19, 2008 Light Pollution and Wildlife This is a very exciting time to be a part of the mission to keep the nighttime skies natural. The International Year of Astronomy (IYA) 2009 is developing programs for all areas of Dark Skies Awareness. For many years the issue of light pollution focused on the impact to the astronomy industry. While this is an important area, research has shown that light pollution negatively impacts wildlife, their habitat, human health, and is a significant waste of energy. Since the message and impact of the effects of light pollution are much broader now, the message conveyed to the public must also be broader. Education programs directed at youth are a new frontier to reach out to a new audience about the adverse effects of too much artificial light at night. The International Dark-Sky Association (IDA) has developed educational presentations using the National Science Teachers Association Education Standards. These programs focus on youth between the ages of 5 to 17exploring new territory in the education of light pollution. The IDA education programs are broken down into three age groups; ages 5-9, 8-13, 12 and older. The presentations come complete with PowerPoint slides, discussion notes for each slide, and workbooks including age appropriate games to keep young audiences involved. A new presentation reflects the growing area of interest regarding the effects of too much artificial light at night on wildlife. This presentation outlines the known problems for ecosystems caused by artificial light at night. Insects are attracted to artificial lights and may stay near that light all night. This attraction interferes with their ability to migrate, mate, and look for food. Such behavior leads to smaller insect populations. Fewer insects in turn affect birds and bats, because they rely on insects as a food source. The IDA

  12. Indoor Air Pollution

    Science.gov (United States)

    We usually think of air pollution as being outdoors, but the air in your house or office could also be polluted. Sources of indoor pollution include Mold and pollen Tobacco smoke Household products ...

  13. Coping with Radio Frequency Interference

    Science.gov (United States)

    Lewis, B. M.

    2009-01-01

    The radio spectrum is a finite resource, on which humanity makes many demands. And pressure on it is ever increasing with the development of new technology and ideas for radio services. After all, we all benefit from wifi and cell phones. Radio astronomers have a small percentage of the spectrum allocated to them at octave intervals in the metre-centimetre bands, and at important frequencies, such as that of the 21cm line of HI. Signals from other services, as well as from our own poorly-engineered equipment, sometimes contaminate our bands: these signals constitute RFI. These may totally obliterate the astronomical signal, or, in the case of CLOUDSAT, may be capable of completely destroying a receiver, which introduces us to the new possibility of 'destructive interference'. A geo-stationary satellite can block access to a piece of sky from one site. Good equipment design eliminates self-inflicted interference, while physical separation often provides adequate practical mitigation at many frequencies. However, new observatories end up being located in the West Australian desert or Antarctica. In future they may be on the back side of the Moon. But there is no Earth-bound protection via physical separation against satellite signals. Some mitigation can be achieved by frequent data dumps and the excision of RFI, or by real-time detection and blanking of the receiver, or by more sophisticated algoriths. Astronomers of necessity aim to achieve mitigation via coordination, at the local level, and by participating in spectrum management at the national and international levels. This involves them spending a lot of time in Geneva at the International Telegraphic Union protecting their access to spectrum, and access to clean spectrum from the L3 point and the far side of the Moon.

  14. Filtering algorithm for dotted interferences

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K., E-mail: kurt.osterloh@bam.de [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Buecherl, T.; Lierse von Gostomski, Ch. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany); Zscherpel, U.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Bock, S. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany)

    2011-09-21

    An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible.

  15. Filtering algorithm for dotted interferences

    International Nuclear Information System (INIS)

    Osterloh, K.; Buecherl, T.; Lierse von Gostomski, Ch.; Zscherpel, U.; Ewert, U.; Bock, S.

    2011-01-01

    An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible.

  16. Proactive Interference in Human Predictive Learning

    OpenAIRE

    Castro, Leyre; Ortega, Nuria; Matute, Helena

    2002-01-01

    The impairment in responding to a secondly trained association because of the prior training of another (i.e., proactive interference) is a well-established effect in human and animal research, and it has been demonstrated in many paradigms. However, learning theories have been concerned with proactive interference only when the competing stimuli have been presented in compound at some moment of the training phase. In this experiment we investigated the possibility of proactive interference b...

  17. Laser reflector with an interference coating

    International Nuclear Information System (INIS)

    Vol'pyan, O D; Semenov, A A; Yakovlev, P P

    1998-01-01

    An analysis was made of the reflectivity of interference coatings intended for the use in optical pumping of solid-state lasers. Ruby and Nd 3+ :YAG lasers were used as models in comparative pumping efficiency measurements, carried out employing reflectors with interference and silver coatings. Estimates of the service life of reflectors with interference coatings were obtained. The power of a thermo-optical lens was reduced by the use of such coatings in cw lasers. (laser system components)

  18. Optical recording in functional polymer nanocomposites by multi-beam interference holography

    Science.gov (United States)

    Zhuk, Dmitrij; Burunkova, Julia; Kalabin, Viacheslav; Csarnovics, Istvan; Kokenyesi, Sandor

    2017-05-01

    Our investigations relate to the development of new polymer nanocomposite materials and technologies for fabrication of photonic elements like gratings, integrated elements, photonic crystals. The goal of the present work was the development and application of the multi-beam interference method for one step, direct formation of 1-, 2- or even 3D photonic structures in functional acrylate nanocomposites, which contain SiO2 and Au nanoparticles and which are sensitized to blue and green laser illumination. The presence of gold nanoparticles and possibility to excite plasmonic effects can essentially influence the polymerization processes and the spatial redistribution of nanoparticles in the nanocomposite during the recording. This way surface and volume phase reliefs can be recorded. It is essential, that no additional treatments of the material after the recording are necessary and the elements possess high transparency, are stable after some relaxation time. New functionalities can be provided to the recorded structures if luminescent materials are added to such materials.

  19. Ag induced electromagnetic interference shielding of Ag-graphite/PVDF flexible nanocomposites thinfilms

    Science.gov (United States)

    Kumaran, R.; Alagar, M.; Dinesh Kumar, S.; Subramanian, V.; Dinakaran, K.

    2015-09-01

    We report Ag nanoparticle induced Electromagnetic Interference (EMI) shielding in a flexible composite films of Ag nanoparticles incorporated graphite/poly-vinylidene difluoride (PVDF). PVDF nanocomposite thin-films were synthesized by intercalating Ag in Graphite (GIC) followed by dispersing GIC in PVDF. The X-ray diffraction analysis and the high-resolution transmission electron microscope clearly dictate the microstructure of silver nanoparticles in graphite intercalated composite of PVDF matrix. The conductivity values of nanocomposites are increased upto 2.5 times when compared to neat PVDF having a value of 2.70 S/cm at 1 MHz. The presence of Ag broadly enhanced the dielectric constant and lowers the dielectric loss of PVDF matrix proportional to Ag content. The EMI shielding effectiveness of the composites is 29.1 dB at 12.4 GHz for the sample having 5 wt. % Ag and 10 wt. % graphite in PVDF.

  20. USCG Vessel Pollution

    Data.gov (United States)

    Department of Homeland Security — The Marine Casualty and Pollution Data files provide details about marine casualty and pollution incidents investigated by Coast Guard Offices throughout the United...

  1. USCG Facility Pollution

    Data.gov (United States)

    Department of Homeland Security — The Marine Casualty and Pollution Data files provide details about marine casualty and pollution incidents investigated by Coast Guard Offices throughout the United...

  2. Using Interference to Block RFID Tags

    DEFF Research Database (Denmark)

    Krigslund, Rasmus; Popovski, Petar; Pedersen, Gert Frølund

    We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag.......We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag....

  3. Electromagnetic Interference (EMI) and TEMPEST Test Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Electromagnetic Interference (EMI), Electromagnetic Compatibility (EMC) and TEMPEST testing are conducted at EPG's Blacktail Canyon Test Facility in one of its two...

  4. Chlorinated Cyanurates: Method Interferences and Application Implications

    Science.gov (United States)

    Experiments were conducted to investigate method interferences, residual stability, regulated DBP formation, and a water chemistry model associated with the use of Dichlor & Trichlor in drinking water.

  5. A study on the effect of chemically synthesized magnetite nanoparticles on earthworm: Eudrilus eugeniae

    Science.gov (United States)

    Samrot, Antony V.; Justin, C.; Padmanaban, S.; Burman, Ujjala

    2017-02-01

    Most look into the benefits of the nanoparticles, but keeping aside the benefits; this study focuses on the impacts of nanoparticles on living systems. Improper disposal of nanoparticles into the environment is a subject of pollution or nano-pollution which in turn affects the flora and fauna in the ecosystem, particularly soil ecosystem. Thus, this study was done to understand the impacts of chemically synthesized magnetite nanoparticles on earthworm— Eudrilus eugeniae, a soil-dependent organism which acquires food and nutrition from decaying matters. The chemically synthesized magnetite nanoparticles were characterized by UV-visible spectrophotometry, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Earthworms were allowed to interact with different concentrations of synthesized nanoparticles and the effect of the nanoparticles was analysed by studying the phenotypic changes followed by histology and inductively coupled plasma optical emission spectrometry analyses.

  6. INTERFERENCE OF COUNTERPROPAGATING SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-03-01

    -dynamic discontinuities, the intensities corresponding to the transition from regular to irregular interference were described. Numerical calculations of the shock-wave structure transformation in the conditions of hysteresis were performed. The results were compared with the experiments carried out by hydraulic analogy method. Practical significance. Results of the work complement well the theory of stationary gas-dynamic discontinuities interference and can be used at designing of perspective images of supersonic and hypersonic aircraft.

  7. Stroop interference and reverse Stroop interference as potential measures of cognitive ability during exposure to stress

    OpenAIRE

    景山, 望; 箱田, 裕司; Kageyama, Nozomu; Hakoda, Yuji

    2011-01-01

    Stroop interference and reverse-Stroop interference are one of the easiest and most powerful effects to demonstrate in a classroom. Therefore, they have been studied not only through basic research in the laboratory but also through applied research in extreme environments. First, we reviewed studies tha investigated Stroop interference and reverse-Stroop interference as hallmark measures of selective at attention and conflict resolution. Second, we reviewed studies that examined the effects ...

  8. Neural mechanisms of interference control in working memory: effects of interference expectancy and fluid intelligence.

    Directory of Open Access Journals (Sweden)

    Gregory C Burgess

    2010-09-01

    Full Text Available A critical aspect of executive control is the ability to limit the adverse effects of interference. Previous studies have shown activation of left ventrolateral prefrontal cortex after the onset of interference, suggesting that interference may be resolved in a reactive manner. However, we suggest that interference control may also operate in a proactive manner to prevent effects of interference. The current study investigated the temporal dynamics of interference control by varying two factors - interference expectancy and fluid intelligence (gF - that could influence whether interference control operates proactively versus reactively.A modified version of the recent negatives task was utilized. Interference expectancy was manipulated across task blocks by changing the proportion of recent negative (interference trials versus recent positive (facilitation trials. Furthermore, we explored whether gF affected the tendency to utilize specific interference control mechanisms. When interference expectancy was low, activity in lateral prefrontal cortex replicated prior results showing a reactive control pattern (i.e., interference-sensitivity during probe period. In contrast, when interference expectancy was high, bilateral prefrontal cortex activation was more indicative of proactive control mechanisms (interference-related effects prior to the probe period. Additional results suggested that the proactive control pattern was more evident in high gF individuals, whereas the reactive control pattern was more evident in low gF individuals.The results suggest the presence of two neural mechanisms of interference control, with the differential expression of these mechanisms modulated by both experimental (e.g., expectancy effects and individual difference (e.g., gF factors.

  9. The Nature and Diagnosis of Interference Phenomena.

    Science.gov (United States)

    Denison, Norman

    1966-01-01

    The recognition of the systematic nature of the interference of the mother tongue when learning a second language is among the most significant advances in linguistics for the teaching and learning of foreign languages. The work of Weinreich showed that interference between language systems--the absorption of loan words, calques, and phonological,…

  10. Interferences in place attachment: implications for wilderness

    Science.gov (United States)

    Erin K. Sharpe; Alan W. Ewert

    2000-01-01

    Previous research on place attachment has tended to focus on attachment formation, with relatively little attention given to factors that disrupt or interfere with formed place attachments. Interferences to attachments are a worthy research area for two reasons: 1) The factors of place attachment are often more salient when being disrupted, and 2) place attachment...

  11. Interference and the Law of Energy Conservation

    Science.gov (United States)

    Drosd, Robert; Minkin, Leonid; Shapovalov, Alexander S.

    2014-01-01

    Introductory physics textbooks consider interference to be a process of redistribution of energy from the wave sources in the surrounding space resulting in constructive and destructive interferences. As one can expect, the total energy flux is conserved. However, one case of apparent non-conservation energy attracts great attention. Imagine that…

  12. 47 CFR 24.237 - Interference protection.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 2 2010-10-01 2010-10-01 false Interference protection. 24.237 Section 24.237... SERVICES Broadband PCS § 24.237 Interference protection. (a) All licensees are required to coordinate their... protection criterion shall be such that the interfering signal will not produce more than 1.0 dB degradation...

  13. Optimal interference code based on machine learning

    Science.gov (United States)

    Qian, Ye; Chen, Qian; Hu, Xiaobo; Cao, Ercong; Qian, Weixian; Gu, Guohua

    2016-10-01

    In this paper, we analyze the characteristics of pseudo-random code, by the case of m sequence. Depending on the description of coding theory, we introduce the jamming methods. We simulate the interference effect or probability model by the means of MATLAB to consolidate. In accordance with the length of decoding time the adversary spends, we find out the optimal formula and optimal coefficients based on machine learning, then we get the new optimal interference code. First, when it comes to the phase of recognition, this study judges the effect of interference by the way of simulating the length of time over the decoding period of laser seeker. Then, we use laser active deception jamming simulate interference process in the tracking phase in the next block. In this study we choose the method of laser active deception jamming. In order to improve the performance of the interference, this paper simulates the model by MATLAB software. We find out the least number of pulse intervals which must be received, then we can make the conclusion that the precise interval number of the laser pointer for m sequence encoding. In order to find the shortest space, we make the choice of the greatest common divisor method. Then, combining with the coding regularity that has been found before, we restore pulse interval of pseudo-random code, which has been already received. Finally, we can control the time period of laser interference, get the optimal interference code, and also increase the probability of interference as well.

  14. Electron quantum interferences and universal conductance fluctuations

    International Nuclear Information System (INIS)

    Benoit, A.; Pichard, J.L.

    1988-05-01

    Quantum interferences yield corrections to the classical ohmic behaviour predicted by Boltzmann theory in electronic transport: for instance the well-known ''weak localization'' effects. Furthermore, very recently, quantum interference effects have been proved to be responsible for statistically different phenomena, associated with Universal Conductance Fluctuations and observed on very small devices [fr

  15. Complete destructive interference of partially coherent fields

    NARCIS (Netherlands)

    Gbur, G.J.; Visser, T.D.; Wolf, E.

    2004-01-01

    A three-point source model is used to study the interference of wavefields which are mutually partially coherent. It is shown that complete destructive interference of the fields is possible in such a "three-pinhole interferometer" even if the sources are not fully coherent with respect to each

  16. STRUCTURE FORMATION PRINCIPLES OF INTERFERENCE BEAM SPLITTERS

    Directory of Open Access Journals (Sweden)

    L. A. Gubanova

    2012-01-01

    Full Text Available The methodology of interference beam splitters construction, formed by symmetric cells of dielectric layers is considered. The methodology of short-wave and long-wave interference beam splitters formation is given. The impact analysis of symmetric cells number and their structure on output parameters is considered.

  17. Asymptomatic Bacteriuria and Bacterial Interference.

    Science.gov (United States)

    Nicolle, Lindsay E

    2015-10-01

    Asymptomatic bacteriuria is very common. In healthy women, asymptomatic bacteriuria increases with age, from women age 80 years, but is uncommon in men until after age 50 years. Individuals with underlying genitourinary abnormalities, including indwelling devices, may also have a high frequency of asymptomatic bacteriuria, irrespective of age or gender. The prevalence is very high in residents of long-term-care facilities, from 25% to 50% of women and 15% to 40% of men. Escherichia coli is the most frequent organism isolated, but a wide variety of other organisms may occur. Bacteriuria may be transient or persist for a prolonged period. Pregnant women with asymptomatic bacteriuria identified in early pregnancy and who are untreated have a risk of pyelonephritis later in pregnancy of 20% to 30%. Bacteremia is frequent in bacteriuric subjects following mucosal trauma with bleeding, with 5% to 10% of patients developing severe sepsis or septic shock. These two groups with clear evidence of negative outcomes should be screened for bacteriuria and appropriately treated. Asymptomatic bacteriuria in other populations is benign and screening and treatment are not indicated. Antimicrobial treatment has no benefits but is associated with negative outcomes including reinfection with antimicrobial resistant organisms and a short-term increased frequency of symptomatic infection post-treatment. The observation of increased symptomatic infection post-treatment, however, has led to active investigation of bacterial interference as a strategy to prevent symptomatic episodes in selected high risk patients.

  18. Belief attribution despite verbal interference.

    Science.gov (United States)

    Forgeot d'Arc, Baudouin; Ramus, Franck

    2011-05-01

    False-belief (FB) tasks have been widely used to study the ability of individuals to represent the content of their conspecifics' mental states (theory of mind). However, the cognitive processes involved are still poorly understood, and it remains particularly debated whether language and inner speech are necessary for the attribution of beliefs to other agents. We present a completely nonverbal paradigm consisting of silent animated cartoons in five closely related conditions, systematically teasing apart different aspects of scene analysis and allowing the assessment of the attribution of beliefs, goals, and physical causation. In order to test the role of language in belief attribution, we used verbal shadowing as a dual task to inhibit inner speech. Data on 58 healthy adults indicate that verbal interference decreases overall performance, but has no specific effect on belief attribution. Participants remained able to attribute beliefs despite heavy concurrent demands on their verbal abilities. Our results are most consistent with the hypothesis that belief attribution is independent from inner speech.

  19. Light pollution : working paper

    NARCIS (Netherlands)

    Lechner, Stefan; Arns, Marieke

    2013-01-01

    Light pollution is one of the fastest growing and most pervasive of environmental pollution (Chepesiuk, 2009). In the last couple of years, a lot of research has been done about the effects of light pollution. The interest in light pollution has been growing in many fields of science, extending from

  20. Poloxamer-Decorated Polymer Nanoparticles for Lung Surfactant Compatibility

    DEFF Research Database (Denmark)

    Beck-Broichsitter, Moritz; Bohr, Adam; Ruge, Christian A

    2017-01-01

    Lung-delivered polymer nanoparticles provoked dysfunction of the essential lung surfactant system. A steric shielding of the nanoparticle surface with poloxamers could minimize the unwanted interference of polymer nanoparticles with the biophysical function of lung surfactant. The extent of poly......(styrene) and poly(lactide) nanoparticle-induced lung surfactant inhibition could be related to the type and content of the applied poloxamer. Escalations of the adsorbed coating layer thickness (>3 nm) as well as concentration (brush- rather than mushroom-like conformation of poly(ethylene glycol), chain......-associated proteins. Poloxamer-modified polymer nanoparticles represent a promising nanomedicine platform intended for respiratory delivery revealing negligible effects on the biophysical functionality of the lining layer present in the deep lungs....

  1. Laser self-mixing interference fibre sensor

    International Nuclear Information System (INIS)

    Zhu Jun; Zhao Yan; Jin Guofan

    2008-01-01

    Fibre sensors exhibit a number of advantages over other sensors such as high sensitivity, electric insulation, corrosion resistance, interference rejection and so on. And laser self-mixing interference can accurately detect the phase difference of feedback light. In this paper, a novel laser self-mixing interference fibre sensor that combines the advantages of fibre sensors with those of laser self-mixing interference is presented. Experimental configurations are set up to study the relationship between laser power output and phase of laser feedback light when the fibre trembles or when the fibre is stretched or pressed. The theoretical analysis of pressure sensors based on laser self-mixing interference is indicated to accord with the experimental results. (classical areas of phenomenology)

  2. Collision-induced destructive quantum interference

    International Nuclear Information System (INIS)

    Yang Xihua; Sun Zhenrong; Zhang Shi'an; Ding Liang'en; Wang Zugeng

    2005-01-01

    We conduct theoretical studies on the collision-induced destructive quantum interference of two-colour two-photon transitions in an open rhomb-type five-level system with a widely separated doublet by the density matrix approach. The effects of the collision-induced decay rates, the ratio of the transition dipole moments and the energy separation of the doublet on the interference are analysed. It is shown that a narrow dip appears in the excitation spectrum due to the collision-induced destructive interference, and that the narrow interference dip still exists even when the collision broadening is comparable to the energy separation of the doublet. The physical origin of the collision-induced destructive quantum interference is analysed in the dressed-atom picture

  3. Pollution management system

    DEFF Research Database (Denmark)

    2015-01-01

    A pollution management system comprises an array of one or more inlets and at least one outlet. The one or more inlets are arranged to collect polluted air and supply said polluted air to a polluted air treatment element. The one or more inlets each comprise a respective inlet sensor for measuring...... a level of pollution at the inlet, and the at least one outlet comprises an outlet sensor for measuring a level of pollution at the outlet. The inlet sensors and the outlet sensor are arranged to provide feedback to the polluted air treatment element....

  4. Biopolymeric nanoparticles

    International Nuclear Information System (INIS)

    Sundar, Sushmitha; Kundu, Joydip; Kundu, Subhas C

    2010-01-01

    This review on nanoparticles highlights the various biopolymers (proteins and polysaccharides) which have recently revolutionized the world of biocompatible and degradable natural biological materials. The methods of their fabrication, including emulsification, desolvation, coacervation and electrospray drying are described. The characterization of different parameters for a given nanoparticle, such as particle size, surface charge, morphology, stability, structure, cellular uptake, cytotoxicity, drug loading and drug release, is outlined together with the relevant measurement techniques. Applications in the fields of medicine and biotechnology are discussed along with a promising future scope. (topical review)

  5. Matrix effects on organic pollutants analysis in marine sediment

    Science.gov (United States)

    Azis, M. Y.; Asia, L.; Piram, A.; Buchari, B.; Doumenq, P.; Setiyanto, H.

    2018-05-01

    Interference from the matrix sample can influence of the accurate analytical method. Accelerated Solvent Extraction and their purification methods were tried to separate the organic micropollutants respectively in marine sediment. Those matrix were as organic pollutants evaluation in marine environment. Polychlorinated Biphenyls (PCBs) and Organochlorine pesticides (OCPs) are two examples organic pollutant in environment which are carcinogenic and mutagenic. Marine sediments are important matrices of information regarding the human activities in coastal areas as well as the fate and behavior of organic pollutants, which are persistent in long-term. This research purpose to evaluate the matrice effect and the recovery from marine sediment spiking with several standar solution and deuterium of molecular target from organic pollutants in not polluted sample of sediment. Matrice samples was tested from indicate in unpolluted location. The methods were evaluated with standard calibration curve (linearity LOQ). Recovery (YE) relative, Matrice Effect (ME) relative correction with deuteriated standar were evaluated the interference the matrix. Interference effect for OCPs compounds were higher than PCBs in marine sediment.

  6. Recent Trends in Rapid Environmental Monitoring of Pathogens and Toxicants: Potential of Nanoparticle-Based Biosensor and Applications

    Science.gov (United States)

    Koedrith, Preeyaporn; Thasiphu, Thalisa; Weon, Jong-Il; Boonprasert, Rattana; Tuitemwong, Kooranee; Tuitemwong, Pravate

    2015-01-01

    Of global concern, environmental pollution adversely affects human health and socioeconomic development. The presence of environmental contaminants, especially bacterial, viral, and parasitic pathogens and their toxins as well as chemical substances, poses serious public health concerns. Nanoparticle-based biosensors are considered as potential tools for rapid, specific, and highly sensitive detection of the analyte of interest (both biotic and abiotic contaminants). In particular, there are several limitations of conventional detection methods for water-borne pathogens due to low concentrations and interference with various enzymatic inhibitors in the environmental samples. The increase of cells to detection levels requires long incubation time. This review describes current state of biosensor nanotechnology, the advantage over conventional detection methods, and the challenges due to testing of environmental samples. The major approach is to use nanoparticles as signal reporter to increase output rather than spending time to increase cell concentrations. Trends in future development of novel detection devices and their advantages over other environmental monitoring methodologies are also discussed. PMID:25884032

  7. Photocatalytic degradation properties of α-Fe2O3 nanoparticles for dibutyl phthalate in aqueous solution system

    Science.gov (United States)

    Liu, Yue; Sun, Nan; Hu, Jianshe; Li, Song; Qin, Gaowu

    2018-04-01

    The phthalate ester compounds in industrial wastewater, as kinds of environmental toxic organic pollutants, may interfere with the body's endocrine system, resulting in great harm to humans. In this work, the photocatalytic degradation properties of dibutyl phthalate (DBP) were investigated using α-Fe2O3 nanoparticles and H2O2 in aqueous solution system. The optimal parameters and mechanism of degradation were discussed by changing the morphology and usage amount of catalysts, the dosage of H2O2, pH value and the initial concentration of DBP. Hollow α-Fe2O3 nanoparticles showed the highest degradation efficiency when 30 mg of catalyst and 50 µl of H2O2 were used in the DBP solution with the initial concentration of 13 mg l-1 at pH = 6.5. When the reaction time was 90 min, DBP was degraded 93% for the above optimal parameters. The photocatalytic degradation mechanism of DBP was studied by the gas chromatography-mass spectrometry technique. The result showed that the main degradation intermediates of DBP were ortho-phthalate monobutyl ester, methyl benzoic acid, benzoic acid, benzaldehyde, and heptyl aldehyde when the reaction time was 2 h. DBP and its intermediates were almost completely degraded to CO2 and H2O in 12 h in the α-Fe2O3/ H2O2/UV system.

  8. Experimental occlusal interferences. Part II. Masseteric EMG responses to an intercuspal interference.

    Science.gov (United States)

    Christensen, L V; Rassouli, N M

    1995-07-01

    In 12 subjects, a rigid unilateral intercuspal interference (minimum mean height of 0.24 mm) was placed on either the right or left mandibular second premolar and first molar (sagittal physiological equilibrium point of the hemimandibular dental arch). During brisk and forceful clenching on the interference, bipolar surface electromyograms were obtained from the right and left masseter muscles. On the side opposite the interference, myoelectric clenching activity was significantly reduced. Correlation analyses showed that the interference elicited a non-linear (complex) co-ordination of the amplitude, but not the duration, of bilateral masseteric clenching activity, i.e. frequently there was significant motor facilitation on the side of the interference, and significant motor inhibition on the side opposite the interference. Theoretical considerations predicted that brief clenching on the interference would easily lead to frontal plane rotatory motions of the mandible which, indeed, occurred clinically.

  9. Robust Nanoparticles

    Science.gov (United States)

    2015-01-21

    avenues for creating flexible conducting and semiconducting materials in a variety of simple or complex geometries. B. Conducting nanoparticle...coated with poly(MPC-co-DHLA) proved stable against challenging conditions, and resisted cyanide ion digestion. Au NRs coated with poly(MPC-co-DHLA

  10. Pyridine-functionalized Fe₃O₄ nanoparticles as a novel sorbent for the preconcentration of lead and cadmium ions in tree leaf as a bioindicator of urban traffic pollution.

    Science.gov (United States)

    Sayar, Omid; Zhad, Hamid Reza Lotfi Zadeh; Sadeghi, Omid; Amani, Vahid; Najafi, Ezzatolla; Tavassoli, Najmeh

    2012-12-01

    We have developed a facile and highly sensitive sorbent for cadmium and lead ions. It is based on Fe₃O₄ nanoparticles functionalized with a derivative of picoline and was characterized by scanning electron microscopy, differential thermographic analysis, and elemental analysis. The material can be applied to the preconcentration of lead and cadmium ions. Factors such as the type, concentration and volume of eluent, the pH of the sample solution, the time for extraction, and the volume of the sample were studied. The effects of a variety of ions on preconcentration and recovery of these ions were also investigated. The ions were determined by FAAS, and the limits of detection are lead and cadmium, respectively. Recoveries and precisions are >98.0 % and <1.3 %, respectively. The method was validated by analyzing several certified leaf reference materials.

  11. Toxicity of zinc oxide nanoparticles to the annelid Enchytraeus crypticus in agar-based exposure media

    Czech Academy of Sciences Publication Activity Database

    Hrdá, K.; Opršál, J.; Knotek, P.; Pouzar, M.; Vlček, Milan

    2016-01-01

    Roč. 70, č. 11 (2016), s. 1512-1520 ISSN 0366-6352 Institutional support: RVO:61389013 Keywords : terrestrial ecotocicity test * zinc ocide nanoparticles * potworm Subject RIV: DJ - Water Pollution ; Quality Impact factor: 1.258, year: 2016

  12. Green synthesis of metal nanoparticles: biodegradable polymers and enzymes in stabilization and surface functionalization

    Science.gov (United States)

    Current breakthroughs in green nanotechnology are capable to transform many of the existing processes and products that enhance environmental quality, reduce pollution, and conserve natural and non-renewable resources. Noteworthy, successful use of metal nanoparticles and 10 nano...

  13. Neurogenesis-mediated forgetting minimizes proactive interference.

    Science.gov (United States)

    Epp, Jonathan R; Silva Mera, Rudy; Köhler, Stefan; Josselyn, Sheena A; Frankland, Paul W

    2016-02-26

    Established memories may interfere with the encoding of new memories, particularly when existing and new memories overlap in content. By manipulating levels of hippocampal neurogenesis, here we show that neurogenesis regulates this form of proactive interference. Increasing hippocampal neurogenesis weakens existing memories and, in doing so, facilitates the encoding of new, conflicting (but not non-conflicting) information in mice. Conversely, decreasing neurogenesis stabilizes existing memories, and impedes the encoding of new, conflicting information. These results suggest that reduced proactive interference is an adaptive benefit of neurogenesis-induced forgetting.

  14. Fingerprint extraction from interference destruction terahertz spectrum.

    Science.gov (United States)

    Xiong, Wei; Shen, Jingling

    2010-10-11

    In this paper, periodic peaks in a terahertz absorption spectrum are confirmed to be induced from interference effects. Theoretically, we explained the periodic peaks and calculated the locations of them. Accordingly, a technique was suggested, with which the interference peaks in a terahertz spectrum can be eliminated and therefore a real terahertz absorption spectrum can be obtained. Experimentally, a sample, Methamphetamine, was investigated and its terahertz fingerprint was successfully extracted from its interference destruction spectrum. This technique is useful in getting samples' terahertz fingerprint spectra, and furthermore provides a fast nondestructive testing method using a large size terahertz beam to identify materials.

  15. Experimental occlusal interferences. Part III. Mandibular rotations induced by a rigid interference.

    Science.gov (United States)

    Rassouli, N M; Christensen, L V

    1995-10-01

    A rigid intercuspal interference (minimum mean height of 0.24 mm) was placed on either the right or left mandibular second premolar and first molar of 12 subjects. During brisk and forceful biting on the interference, rotational electrognathography measured maximum torque of the right and left mandibular condyles in the frontal and horizontal planes of orientation. All subjects showed frontal plan upward rotation (mean of 0.7 degrees) of the mandibular condyle contralateral to the interference. In 33% of the subjects there was no horizontal plane backward rotation. In 58% of the subjects there was horizontal plane backward rotation (mean of 0.5 degrees) of the mandibular condyle ipsilateral to the interference, and in one subject (8%) there was backward horizontal plane rotation (0.1 degree) of the mandibular condyle contralateral to the interference. It was inferred that the masseter muscle, ipsilateral to the interference, generated negative work in order to decelerate frontal plane 'unseating' of the mandibular condyle ipsilateral to the interference. It was inferred that the masseter muscle, contralateral to the interference, produced positive work in order to accelerate frontal plane 'seating' of the mandibular condyle contralateral to the interference. Finally, it was speculated that the impact forces of frontal plane 'seating' of the mandibular condyle, contralateral to the interference, might lead to 'vacuum sticking' of the temporomandibular joint disc because of the formation of negative hydrostatic pressures.

  16. Fundamental investigations of catalyst nanoparticles

    DEFF Research Database (Denmark)

    Elkjær, Christian Fink

    and economic development in the 20th century. There is however a downside to this development and we are seeing significant pollution and pressure on resources. Catalysis therefore has an increasingly important role in limiting pollution and optimizing the use of resources. This development will depend on our...... fundamental understanding of catalytic processes and our ability to make use of that understanding. This thesis presents fundamental studies of catalyst nanoparticles with particular focus on dynamic processes. Such studies often require atomic-scale characterization, because the catalytic conversion takes...... important that we only study intrinsic structures and phenomena and not those that may be induced by the high energy electrons used to image the specimen. This requires careful consideration of the influence of the electron beam in order to understand, control and minimize that influence. I present four...

  17. MgO nanoparticles as antibacterial agent: preparation and activity

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhen-Xing, E-mail: tangzhenxing@126.com [Department of Food Science, Anqing, Vocational and Technical College, Anqing, Anhui (China); Lv, Bin-Feng [Date Palm Research Center, King Faisal University, (Saudi Arabia)

    2014-07-15

    Bacterial pollution is a great risk for human health. Nanotechnology offers a way to develop new inorganic antibacterial agents. Nano-inorganic metal oxide has a potential to reduce bacterial contamination. MgO is an important inorganic oxide and has been widely used in many fields. Many studies have shown that MgO nanoparticles have good antibacterial activity. Therefore, in this paper, the main synthesis methods, antibacterial activity and antibacterial mechanisms of MgO nanoparticles are reviewed. (author)

  18. MgO nanoparticles as antibacterial agent: preparation and activity

    International Nuclear Information System (INIS)

    Tang, Zhen-Xing; Lv, Bin-Feng

    2014-01-01

    Bacterial pollution is a great risk for human health. Nanotechnology offers a way to develop new inorganic antibacterial agents. Nano-inorganic metal oxide has a potential to reduce bacterial contamination. MgO is an important inorganic oxide and has been widely used in many fields. Many studies have shown that MgO nanoparticles have good antibacterial activity. Therefore, in this paper, the main synthesis methods, antibacterial activity and antibacterial mechanisms of MgO nanoparticles are reviewed. (author)

  19. Detection device for control rod interference

    International Nuclear Information System (INIS)

    Saito, Noboru.

    1984-01-01

    Purpose: To enable to detect the mechanical interference or friction between a control rod and a channel box automatically, simply and rapidly. Constitution: A signal from a gate circuit and a signal from a comparison mechanism are inputted into an AND circuit if a control rod has not been displaced by a predetermined distance within a prescribed time Δt after the output of an insertion or withdrawal signal for the control rod, by which a control-rod-interference signal is outputted from the AND circuit. Accordingly, the interference between the control rod and the channel box can be detected automatically, easily and rapidly. Furthermore, by properly adjusting the prescribed time Δt set by the gate circuit, the degree of the interference can also be detected, whereby the safety and the reliability of the reactor can be improved significantly. (Horiuchi, T.)

  20. Interference-exact radiative transfer equation

    DEFF Research Database (Denmark)

    Partanen, Mikko; Haÿrynen, Teppo; Oksanen, Jani

    2017-01-01

    Maxwell's equations with stochastic or quantum optical source terms accounting for the quantum nature of light. We show that both the nonlocal wave and local particle features associated with interference and emission of propagating fields in stratified geometries can be fully captured by local damping...... and scattering coefficients derived from the recently introduced quantized fluctuational electrodynamics (QFED) framework. In addition to describing the nonlocal optical interference processes as local directionally resolved effects, this allows reformulating the well known and widely used radiative transfer...... equation (RTE) as a physically transparent interference-exact model that extends the useful range of computationally efficient and quantum optically accurate interference-aware optical models from simple structures to full optical devices....

  1. Cognitive interference management in heterogeneous networks

    CERN Document Server

    Marabissi, Dania

    2015-01-01

    This brief investigates the role of interference management in Heterogeneous Networks (Het Nets), focusing on cognitive approaches and the use of beamforming. Key concepts of Het Nets are introduced and different deployment strategies are examined, such as sharing the same frequency band of the macro cells or using new high frequency bands. Particular attention is devoted to co-channel deployment and to the problem of interference management, addressing various strategies that can be adopted to handle the interference between the cells. In addition, the brief explores cognitive small cells which are able to avoid or limit interference by using suitable beamforming and resource allocation schemes. The suggested solutions are supported by numerical results in terms of performance evaluations and comparisons.

  2. Relay self interference minimisation using tapped filter

    KAUST Repository

    Jazzar, Saleh; Al-Naffouri, Tareq Y.

    2013-01-01

    In this paper we introduce a self interference (SI) estimation and minimisation technique for amplify and forward relays. Relays are used to help forward signals between a transmitter and a receiver. This helps increase the signal coverage

  3. Assessment of life interference in anxious children

    DEFF Research Database (Denmark)

    Rapee, Ronald; Thastum, Mikael; Chavira, Denise

    associated with mental disorders arguably the key issue of relevance to both sufferers and therapists. Yet among both childhood and adult disorders the primary focus in terms of assessment and treatment is on symptoms, with far less attention paid to the impact of these symptoms on the sufferer's life....... This imbalance has particularly characterised research on child anxiety where few studies have examined either the impact of anxiety disorders on children's lives or the effects of treatments on life interference. To some extent this lack of attention has come from a lack of well developed measures to assess...... life interference derived from symptoms of anxiety. Broader and more general life interference measures tend to have minimal relevance for children with anxiety disorders. The current paper will describe two measures of life interference that have been developed at the Centre for Emotional Health...

  4. Interference Coordination for Dense Wireless Networks

    DEFF Research Database (Denmark)

    Soret, Beatriz; Pedersen, Klaus I.; Jørgensen, Niels T.K.

    2015-01-01

    and dense deployment in Tokyo are compared. Evolution to DenseNets offers new opportunities for further development of downlink interference cooperation techniques. Various mechanisms in LTE and LTE-Advanced are revisited. Some techniques try to anticipate the future in a proactive way, whereas others......The promise of ubiquitous and super-fast connectivity for the upcoming years will be in large part fulfilled by the addition of base stations and spectral aggregation. The resulting very dense networks (DenseNets) will face a number of technical challenges. Among others, the interference emerges...... as an old acquaintance with new significance. As a matter of fact, the interference conditions and the role of aggressor and victim depend to a large extent on the density and the scenario. To illustrate this, downlink interference statistics for different 3GPP simulation scenarios and a more irregular...

  5. Release From Proactive Interference with Young Children

    Science.gov (United States)

    Cann, Linda F.; And Others

    1973-01-01

    This demonstration of release from proactive interference with young children confirms the suggestion that the technique is appropriate for the study of developmental changes in the encoding of information. (Authors/CB)

  6. Conducted Electromagnetic Interference (EMI) in Smart Grids

    CERN Document Server

    Smolenski, Robert

    2012-01-01

    As power systems develop to incorporate renewable energy sources, the delivery systems may be disrupted by the changes involved. The grid’s technology and management must be developed to form Smart Grids between consumers, suppliers and producers. Conducted Electromagnetic Interference (EMI) in Smart Grids considers the specific side effects related to electromagnetic interference (EMI) generated by the application of these Smart Grids. Conducted Electromagnetic Interference (EMI) in Smart Grids presents specific EMI conducted phenomena as well as effective methods to filter and handle them once identified. After introduction to Smart Grids, the following sections cover dedicated methods for EMI reduction and potential avenues for future development including chapters dedicated to: •potential system services, •descriptions of the EMI spectra shaping methods, •methods of interference voltage compensation, and theoretical analysis of experimental results.  By focusing on these key aspects, Conducted El...

  7. Resolving Business Process Interference via Dynamic Reconfiguration

    NARCIS (Netherlands)

    van Beest, Nick R. T. P.; Bulanov, Pavel; Wortmann, Hans; Lazovik, Alexander; Maglio, PP; Weske, M; Yang, J; Fantinato, M

    2010-01-01

    For business processes supported by service-oriented information systems, concurrent execution of business processes still may yield undesired business outcomes as a result of process interference. For instance, concurrent processes may partially depend on a semantically identical process variable,

  8. Optimal pollution trading without pollution reductions

    Science.gov (United States)

    Many kinds of water pollution occur in pulses, e.g., agricultural and urban runoff. Ecosystems, such as wetlands, can serve to regulate these pulses and smooth pollution distributions over time. This smoothing reduces total environmental damages when “instantaneous” damages are m...

  9. Fading and interference mitigation in wireless communications

    CERN Document Server

    Panic, Stefan; Anastasov, Jelena; Spalevic, Petar

    2013-01-01

    The rapid advancement of various wireless communication system services has created the need to analyze the possibility of their performance improvement. Introducing the basic principles of digital communications performance analysis and its mathematical formalization, Fading and Interference Mitigation in Wireless Communications will help you stay up to date with recent developments in the performance analysis of space diversity reception over fading channels in the presence of cochannel interference.The book presents a unified method for computing the performance of digital communication sys

  10. Visual Working Memory Capacity and Proactive Interference

    OpenAIRE

    Hartshorne, Joshua

    2008-01-01

    BACKGROUND: Visual working memory capacity is extremely limited and appears to be relatively immune to practice effects or the use of explicit strategies. The recent discovery that visual working memory tasks, like verbal working memory tasks, are subject to proactive interference, coupled with the fact that typical visual working memory tasks are particularly conducive to proactive interference, suggests that visual working memory capacity may be systematically under-estimated. METHODOLOGY/P...

  11. Interferences of commercial NO2 instruments in the urban atmosphere and in a smog chamber

    Directory of Open Access Journals (Sweden)

    J. Kleffmann

    2012-01-01

    Full Text Available Reliable measurements of atmospheric trace gases are necessary for both, a better understanding of the chemical processes occurring in the atmosphere, and for the validation of model predictions. Nitrogen dioxide (NO2 is a toxic gas and is thus a regulated air pollutant. Besides, it is of major importance for the oxidation capacity of the atmosphere and plays a pivotal role in the formation of ozone and acid precipitation. Detection of NO2 is a difficult task since many of the different commercial techniques used are affected by interferences. The chemiluminescence instruments that are used for indirect NO2 detection in monitoring networks and smog chambers use either molybdenum or photolytic converters and are affected by either positive (NOy or negative interferences (radical formation in the photolytic converter. Erroneous conclusions on NO2 can be drawn if these interferences are not taken into consideration. In the present study, NO2 measurements in the urban atmosphere, in a road traffic tunnel and in a smog-chamber using different commercial techniques, i.e. chemiluminescence instruments with molybdenum or photolytic converters, a Luminol based instrument and a new NO2-LOPAP, were compared with spectroscopic techniques, i.e. DOAS and FTIR. Interferences of the different instruments observed during atmospheric measurements were partly characterised in more detail in the smog chamber experiments. Whereas all the commercial instruments showed strong interferences, excellent agreement was obtained between a new NO2-LOPAP instrument and the FTIR technique for the measurements performed in the smog chamber.

  12. Cross-limb interference during motor learning.

    Directory of Open Access Journals (Sweden)

    Benedikt Lauber

    Full Text Available It is well known that following skill learning, improvements in motor performance may transfer to the untrained contralateral limb. It is also well known that retention of a newly learned task A can be degraded when learning a competing task B that takes place directly after learning A. Here we investigate if this interference effect can also be observed in the limb contralateral to the trained one. Therefore, five different groups practiced a ballistic finger flexion task followed by an interfering visuomotor accuracy task with the same limb. Performance in the ballistic task was tested before the training, after the training and in an immediate retention test after the practice of the interference task for both the trained and the untrained hand. After training, subjects showed not only significant learning and interference effects for the trained limb but also for the contralateral untrained limb. Importantly, the interference effect in the untrained limb was dependent on the level of skill acquisition in the interfering motor task. These behavioural results of the untrained limb were accompanied by training specific changes in corticospinal excitability, which increased for the hemisphere ipsilateral to the trained hand following ballistic training and decreased during accuracy training of the ipsilateral hand. The results demonstrate that contralateral interference effects may occur, and that interference depends on the level of skill acquisition in the interfering motor task. This finding might be particularly relevant for rehabilitation.

  13. Interference in the processing of adjunct control

    Directory of Open Access Journals (Sweden)

    Dan eParker

    2015-09-01

    Full Text Available Recent research on the memory operations used in language comprehension has revealed a selective profile of interference effects during memory retrieval. Dependencies such as subject-verb agreement show strong facilitatory interference effects from structurally inappropriate but feature-matching distractors, leading to illusions of grammaticality (Dillon, Mishler, Sloggett, & Phillips, 2013; Pearlmutter, Garnsey, & Bock, 1999; Wagers, Lau, & Phillips, 2009. In contrast, dependencies involving reflexive anaphors are generally immune to interference effects (Dillon et al., 2013; Sturt, 2003; Xiang, Dillon, & Phillips, 2009. This contrast has led to the proposal that all anaphors that are subject to structural constraints are immune to facilitatory interference. Here we use an animacy manipulation to examine whether adjunct control dependencies, which involve an interpreted anaphoric relation between a null subject and its licensor, are also immune to facilitatory interference effects. Our results show reliable facilitatory interference in the processing of adjunct control dependencies, which challenges the generalization that anaphoric dependencies as a class are immune to such effects. To account for the contrast between adjunct control and reflexive dependencies, we suggest that variability within anaphora could reflect either an inherent primacy of animacy cues in retrieval processes, or differential degrees of match between potential licensors and the retrieval probe.

  14. Investigation of Interference Models for RFID Systems

    Directory of Open Access Journals (Sweden)

    Linchao Zhang

    2016-02-01

    Full Text Available The reader-to-reader collision in an RFID system is a challenging problem for communications technology. In order to model the interference between RFID readers, different interference models have been proposed, mainly based on two approaches: single and additive interference. The former only considers the interference from one reader within a certain range, whereas the latter takes into account the sum of all of the simultaneous interferences in order to emulate a more realistic behavior. Although the difference between the two approaches has been theoretically analyzed in previous research, their effects on the estimated performance of the reader-to-reader anti-collision protocols have not yet been investigated. In this paper, the influence of the interference model on the anti-collision protocols is studied by simulating a representative state-of-the-art protocol. The results presented in this paper highlight that the use of additive models, although more computationally intensive, is mandatory to improve the performance of anti-collision protocols.

  15. Understanding quantum interference in general nonlocality

    International Nuclear Information System (INIS)

    Wang Haijun

    2011-01-01

    In this paper we attempt to give a new understanding of quantum double-slit interference of fermions in the framework of general nonlocality (GN) [J. Math. Phys. 49, 033513 (2008)] by studying the self-(inter)action of matter wave. From the metric of the GN, we derive a special formalism to interpret the interference contrast when the self-action is perturbative. According to the formalism, the characteristic of interference pattern is in agreement with experiment qualitatively. As examples, we apply the formalism to the cases governed by Schroedinger current and Dirac current, respectively, both of which are relevant to topology. The gap between these two cases corresponds to the fermion magnetic moment, which is possible to test in the near future. In addition, a general interference formalism for both perturbative and nonperturbative self-actions is presented. By analyzing the general formalism we predict that in the nonperturbative limit there is no interference at all. And by comparison with the special formalism of Schroedinger current, the coupling strength of self-action in the limit is found to be ∞. In the perturbative case, the interference from self-action turns out to be the same as that from the standard approach of quantum theory. Then comparing the corresponding coefficients quantitatively we conclude that the coupling strength of self-action in this case falls in the interval [0, 1].

  16. Hazardous Air Pollutants

    Science.gov (United States)

    ... Search Main menu Environmental Topics Air Bed Bugs Chemicals and Toxics Environmental Information by Location Greener Living Health Land, ... regulate toxic air pollutants, also known as air toxics, from categories of industrial facilities in two phases . About Hazardous Air Pollutants ...

  17. Lead (Pb) Air Pollution

    Science.gov (United States)

    ... Regional Offices Labs and Research Centers Lead (Pb) Air Pollution Contact Us Share As a result of EPA's ... and protect aquatic and terrestrial ecosystems. Lead (Pb) Air Pollution Basic Information How does lead get in the ...

  18. Marine Pollution Prevention Act

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Marine Pollution Prevention Act of 2008 implements the International Convention for the Prevention of Pollution from Ships, including related Protocols (MARPOL)...

  19. Plasmonic and silicon spherical nanoparticle antireflective coatings

    Science.gov (United States)

    Baryshnikova, K. V.; Petrov, M. I.; Babicheva, V. E.; Belov, P. A.

    2016-03-01

    Over the last decade, plasmonic antireflecting nanostructures have been extensively studied to be utilized in various optical and optoelectronic systems such as lenses, solar cells, photodetectors, and others. The growing interest to all-dielectric photonics as an alternative optical technology along with plasmonics motivates us to compare antireflective properties of plasmonic and all-dielectric nanoparticle coatings based on silver and crystalline silicon respectively. Our simulation results for spherical nanoparticles array on top of amorphous silicon show that both silicon and silver coatings demonstrate strong antireflective properties in the visible spectral range. For the first time, we show that zero reflectance from the structure with silicon coatings originates from the destructive interference of electric- and magnetic-dipole responses of nanoparticle array with the wave reflected from the substrate, and we refer to this reflection suppression as substrate-mediated Kerker effect. We theoretically compare the silicon and silver coating effectiveness for the thin-film photovoltaic applications. Silver nanoparticles can be more efficient, enabling up to 30% increase of the overall absorbance in semiconductor layer. Nevertheless, silicon coatings allow up to 64% absorbance increase in the narrow band spectral range because of the substrate-mediated Kerker effect, and band position can be effectively tuned by varying the nanoparticles sizes.

  20. WMO background air pollution monitoring network (BAPMON)

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, A

    1980-01-01

    The objectives of the network include the establishment of baseline measurements of the global troposphere against which subsequent changes can be measured. The minimum program includes analysis of wet precipitation, observation of the aerosol optical depth, and sampling of suspended particulates. Standardization efforts have resulted in accuracies in rainwater samples to within 10%. Pollutant levels are shown for regional, urban and continental stations. The possibility of establishing median values for different modes of operation at a station (background and nonbackground mode) is examined. The interference of water vapor with CO/sub 2/ measurements is discussed.

  1. Water Pollution, Teachers' Edition.

    Science.gov (United States)

    Lavaroni, Charles W.; And Others

    One of three in a series about pollution, this teacher's guide for a unit on water pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of water pollution and involves students in processes of…

  2. The Other Water Pollution

    Science.gov (United States)

    Barton, Kathy

    1978-01-01

    Nonpoint source pollution, water pollution not released at one specific identifiable point, now accounts for 50 percent of the nation's water pollution problem. Runoff is the primary culprit and includes the following sources: agriculture, mining, hydrologic modifications, and urban runoff. Economics, legislation, practices, and management of this…

  3. Atmospheric Heavy Metal Pollution

    Indian Academy of Sciences (India)

    elements which constitute an important class of pollutants. Such pollutants ... spheric transport processes. In rural regions ... response of redox potential: those which are fixed in reducing conditions ... pollution in urban areas of northern Britain in the eighteenth .... adjusting the desired flame condition, the instrument is cali-.

  4. Water pollution biology

    Energy Technology Data Exchange (ETDEWEB)

    Mason, C.F. [University of Essex, Colchester (United Kingdom). Dept. of Biology

    1996-12-31

    Chapter 4 of this book describes the effects of major types of pollutants on aquatic life. These are: organic pollution, eutrophication, acidification, toxic chemicals, oil, and radioactivity. The review includes an description of some of the methods of assessing the biological impacts of pollution. 50 refs., 8 figs., 3 tabs.

  5. Air Pollution Training Programs.

    Science.gov (United States)

    Public Health Service (DHEW), Rockville, MD.

    This catalog lists the universities, both supported and not supported by the Division of Air Pollution, which offer graduate programs in the field of air pollution. The catalog briefly describes the programs and their entrance requirements, the requirements, qualifications and terms of special fellowships offered by the Division of Air Pollution.…

  6. Noise Pollution, Teachers' Edition.

    Science.gov (United States)

    O'Donnell, Patrick A.; Lavaroni, Charles W.

    One of three in a series about pollution, this teacher's guide for a unit on noise pollution is designed for use in junior high school grades. It offers suggestions for extending the information and activities contained in the textual material for students. Chapter 1 discusses the problem of noise pollution and involves students in processes of…

  7. Microbial control of pollution

    Energy Technology Data Exchange (ETDEWEB)

    Fry, J C; Gadd, G M; Herbert, R A; Jones, C W; Watson-Craik, I A [eds.

    1992-01-01

    12 papers are presented on the microbial control of pollution. Topics covered include: bioremediation of oil spills; microbial control of heavy metal pollution; pollution control using microorganisms and magnetic separation; degradation of cyanide and nitriles; nitrogen removal from water and waste; and land reclamation and restoration.

  8. Design of Superparamagnetic Nanoparticles for Magnetic Particle Imaging (MPI

    Directory of Open Access Journals (Sweden)

    Philip W. T. Pong

    2013-09-01

    Full Text Available Magnetic particle imaging (MPI is a promising medical imaging technique producing quantitative images of the distribution of tracer materials (superparamagnetic nanoparticles without interference from the anatomical background of the imaging objects (either phantoms or lab animals. Theoretically, the MPI platform can image with relatively high temporal and spatial resolution and sensitivity. In practice, the quality of the MPI images hinges on both the applied magnetic field and the properties of the tracer nanoparticles. Langevin theory can model the performance of superparamagnetic nanoparticles and predict the crucial influence of nanoparticle core size on the MPI signal. In addition, the core size distribution, anisotropy of the magnetic core and surface modification of the superparamagnetic nanoparticles also determine the spatial resolution and sensitivity of the MPI images. As a result, through rational design of superparamagnetic nanoparticles, the performance of MPI could be effectively optimized. In this review, the performance of superparamagnetic nanoparticles in MPI is investigated. Rational synthesis and modification of superparamagnetic nanoparticles are discussed and summarized. The potential medical application areas for MPI, including cardiovascular system, oncology, stem cell tracking and immune related imaging are also analyzed and forecasted.

  9. The molecular mass of dextran used to modify magnetite nanoparticles affects insulin amyloid aggregation

    Energy Technology Data Exchange (ETDEWEB)

    Siposova, Katarina [Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia); Pospiskova, Kristyna [Regional Centre of Advanced Technologies and Materials, Palacky University, Olomouc (Czech Republic); Bednarikova, Zuzana [Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia); Department of Biochemistry, Faculty of Science, Safarik University, Kosice (Slovakia); Safarik, Ivo [Regional Centre of Advanced Technologies and Materials, Palacky University, Olomouc (Czech Republic); Department of Nanobiotechnology, Biology Centre, ISB, CAS, Ceske Budejovice (Czech Republic); Safarikova, Mirka [Department of Nanobiotechnology, Biology Centre, ISB, CAS, Ceske Budejovice (Czech Republic); Kubovcikova, Martina; Kopcansky, Peter [Department of Magnetism, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia); Gazova, Zuzana, E-mail: gazova@saske.sk [Department of Biophysics, Institute of Experimental Physics, Slovak Academy of Sciences, Kosice (Slovakia)

    2017-04-01

    Protein transformation from its soluble state into amyloid aggregates is associated with amyloid-related diseases. Amyloid deposits of insulin fibrils have been found in the sites of subcutaneous insulin application in patients with prolonged diabetes. Using atomic force microscopy and ThT fluorescence assay we have investigated the interference of insulin amyloid aggregation with superparamagnetic Fe{sub 3}O{sub 4}-based nanoparticles (SPIONs) coated with dextran (DEX); molecular mass of dextran was equal to 15–20, 40 or 70 kDa. The obtained data indicate that all three types of dextran coated nanoparticles (NP-FeDEXs) are able to inhibit insulin fibrillization and to destroy amyloid fibrils. The extent of anti-amyloid activities depends on the properties of NP-FeDEXs, mainly on the size of nanoparticles which is determined by molecular mass of dextran molecules. The most effective inhibiting activity was observed for the smallest nanoparticles coated with 15–20 kDa dextran. Contrary, the highest destroying activity was observed for the largest NP-FeDEX (70 kDa dextran). - Highlights: • Interference of dextran- magnetite nanoparticles with insulin amyloid aggregation. • Nanoparticles inhibited insulin fibrillization and depolymerized insulin amyloid fibrils. • Size of nanoparticles significantly influences their anti-amyloid activities. • The most effective inhibition of insulin amyloid fibrillization was detected for the smallest nanoparticles. • Contrary, DC{sub 50} values decreased with increasing size of nanoparticles.

  10. The molecular mass of dextran used to modify magnetite nanoparticles affects insulin amyloid aggregation

    International Nuclear Information System (INIS)

    Siposova, Katarina; Pospiskova, Kristyna; Bednarikova, Zuzana; Safarik, Ivo; Safarikova, Mirka; Kubovcikova, Martina; Kopcansky, Peter; Gazova, Zuzana

    2017-01-01

    Protein transformation from its soluble state into amyloid aggregates is associated with amyloid-related diseases. Amyloid deposits of insulin fibrils have been found in the sites of subcutaneous insulin application in patients with prolonged diabetes. Using atomic force microscopy and ThT fluorescence assay we have investigated the interference of insulin amyloid aggregation with superparamagnetic Fe 3 O 4 -based nanoparticles (SPIONs) coated with dextran (DEX); molecular mass of dextran was equal to 15–20, 40 or 70 kDa. The obtained data indicate that all three types of dextran coated nanoparticles (NP-FeDEXs) are able to inhibit insulin fibrillization and to destroy amyloid fibrils. The extent of anti-amyloid activities depends on the properties of NP-FeDEXs, mainly on the size of nanoparticles which is determined by molecular mass of dextran molecules. The most effective inhibiting activity was observed for the smallest nanoparticles coated with 15–20 kDa dextran. Contrary, the highest destroying activity was observed for the largest NP-FeDEX (70 kDa dextran). - Highlights: • Interference of dextran- magnetite nanoparticles with insulin amyloid aggregation. • Nanoparticles inhibited insulin fibrillization and depolymerized insulin amyloid fibrils. • Size of nanoparticles significantly influences their anti-amyloid activities. • The most effective inhibition of insulin amyloid fibrillization was detected for the smallest nanoparticles. • Contrary, DC 50 values decreased with increasing size of nanoparticles.

  11. Exogenous sample contamination. Sources and interference.

    Science.gov (United States)

    Cornes, Michael P

    2016-12-01

    Clinical laboratory medicine is involved in the vast majority of patient care pathways. It has been estimated that pathology results inform 60-70% of critical patient care decisions. The primary goal of the laboratory is to produce precise and accurate results which reflect the true situation in vivo. It is not surprising that interference occurs in laboratory analysis given the complexity of some of the assays used to perform them. Interference is defined as "the effect of a substance upon any step in the determination of the concentration or catalytic activity of the metabolite". Exogenous interferences are defined as those that derive from outside of the body and are therefore not normally found in a specimen and can cause either a positive or negative bias in analytical results. Interferences in analysis can come from various sources and can be classified as endogenous or exogenous. Exogenous substances could be introduced at any point in the sample journey. The laboratory must take responsibility for the quality of results produced. It has a responsibility to have processes in place to identify and minimise the occurrence and effect contamination and interference. To do this well the laboratory needs to work with clinicians and manufacturers. Failure to identify an erroneous result could have an impact on patient care, patient safety and also on hospital budgets. However it is not always easy to recognise interferences. This review summarises the types and sources of exogenous interference and some steps to minimise the impact they have. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

  12. Environmental pollution from new chemical pollutants

    International Nuclear Information System (INIS)

    Ahmed, K.

    1995-01-01

    New chemical pollutants have entered the environment because of industrialisation, urbanization and developments. The new pollutants include polymers, plasticizers, polychlorinated biphenyls, acrylonitriles, detergents, lead, dioxins and pesticides. Investigations showed substational amount of their presence in the environment. Pesticides and polymers can be controlled by using photo sensitizers. Lead pollution in ambient air can be controlled by reducing lead content in the gasoline. Detergents can be controlled by switching over the manufacturing process from ABS to LAS. Dioxins can be controlled by incinerating the chlorinated waste above 1200 C. (author)

  13. Photochemical air pollution

    International Nuclear Information System (INIS)

    Te Winkel, B.H.

    1992-01-01

    During periods of severe photochemical air pollution (smog) the industry in the Netherlands is recommended by the Dutch government to strongly reduce the emissions of air pollutants. For the electric power generating companies it is important to investigate the adequacy of this policy. The purpose of this investigation is to determine the contribution of electric power plants to photochemical air pollution and to assess the efficacy of emission reducing measures. A literature survey on the development of photochemical air pollution was carried out and modelled calculations concerning the share of the electric power plants to the photochemical air pollution were executed

  14. The Study of Quantum Interference in Metallic Photonic Crystals Doped with Four-Level Quantum Dots

    Directory of Open Access Journals (Sweden)

    Hatef Ali

    2010-01-01

    Full Text Available Abstract In this work, the absorption coefficient of a metallic photonic crystal doped with nanoparticles has been obtained using numerical simulation techniques. The effects of quantum interference and the concentration of doped particles on the absorption coefficient of the system have been investigated. The nanoparticles have been considered as semiconductor quantum dots which behave as a four-level quantum system and are driven by a single coherent laser field. The results show that changing the position of the photonic band gap about the resonant energy of the two lower levels directly affects the decay rate, and the system can be switched between transparent and opaque states if the probe laser field is tuned to the resonance frequency. These results provide an application for metallic nanostructures in the fabrication of new optical switches and photonic devices.

  15. Self-organized metal nanostructures through laser-interference driven thermocapillary convection

    International Nuclear Information System (INIS)

    Favazza, C.; Trice, J.; Kalyanaraman, R.; Sureshkumar, R.

    2007-01-01

    Here the authors investigate self-organization and the ensuing length scales when Co films (1-8 nm thick) on SiO 2 surfaces are repeatedly and rapidly melted by nonuniform (interference) laser irradiation. Pattern evolution produces periodic nanowires, which eventually breakup into nanoparticles exhibiting spatial order in the nearest-neighbor (NN) spacing λ NN2 . For films of thickness h 0 >2 nm, λ NN2 ∝h 0 1/2 while the particle radius varies as r p2 ∝h 0 1/2 . This scaling behavior is consistent with pattern formation by a thermocapillary flow and a Rayleigh-like instability. For h 0 ≤2 nm, a hydrodynamic instability of a spinodally unstable film leads to the formation of nanoparticles

  16. Quantifying light pollution

    International Nuclear Information System (INIS)

    Cinzano, P.; Falchi, F.

    2014-01-01

    In this paper we review new available indicators useful to quantify and monitor light pollution, defined as the alteration of the natural quantity of light in the night environment due to introduction of manmade light. With the introduction of recent radiative transfer methods for the computation of light pollution propagation, several new indicators become available. These indicators represent a primary step in light pollution quantification, beyond the bare evaluation of the night sky brightness, which is an observational effect integrated along the line of sight and thus lacking the three-dimensional information. - Highlights: • We review new available indicators useful to quantify and monitor light pollution. • These indicators are a primary step in light pollution quantification. • These indicators allow to improve light pollution mapping from a 2D to a 3D grid. • These indicators allow carrying out a tomography of light pollution. • We show an application of this technique to an Italian region

  17. Water Pollution, Causes and Cures.

    Science.gov (United States)

    Manufacturing Chemists Association, Washington, DC.

    This commentary on sources of water pollution and water pollution treatment systems is accompanied by graphic illustrations. Sources of pollution such as lake bottom vegetation, synthetic organic pollutants, heat pollution, radioactive substance pollution, and human and industrial waste products are discussed. Several types of water purification…

  18. Epulis and pyogenic granuloma with occlusal interference

    Directory of Open Access Journals (Sweden)

    Widowati Witjaksono

    2005-06-01

    Full Text Available In dental clinic of Hospital University Science Malaysia (HUSM, there were cases with Localized Gingival Enlargement (LGE in the oral cavity with occlusal interference. In this study, three cases were observed. They were a 13 - year- old female with fibrous lge around 31 and 32 with occlusal interference in protrusive movement due to X bite, a 15 - year – old female with pyogenic granuloma near 11 & 21 with occlusal interference due to deep bite; and a 24 – year – old female who was eight months in pregnancy with pyogenic granuloma on the 34-35 and severe generalized pregnancy gingivitis with occlusal interference in centric occlusion and lateral movement. Clinical and histopathological diagnosis of the first case showed fibrous epulis, whereas the second and third cases disclosed pyogenic granuloma. Chronic trauma of the gingiva due to occlusal interference was assumed to be the cause of those LGE in case 1 and 2, while in case 3 poor oral hygiene and chronic trauma were assumed to be the etiologic factors.

  19. Autobiographical thinking interferes with episodic memory consolidation.

    Directory of Open Access Journals (Sweden)

    Michael Craig

    Full Text Available New episodic memories are retained better if learning is followed by a few minutes of wakeful rest than by the encoding of novel external information. Novel encoding is said to interfere with the consolidation of recently acquired episodic memories. Here we report four experiments in which we examined whether autobiographical thinking, i.e. an 'internal' memory activity, also interferes with episodic memory consolidation. Participants were presented with three wordlists consisting of common nouns; one list was followed by wakeful rest, one by novel picture encoding and one by autobiographical retrieval/future imagination, cued by concrete sounds. Both novel encoding and autobiographical retrieval/future imagination lowered wordlist retention significantly. Follow-up experiments demonstrated that the interference by our cued autobiographical retrieval/future imagination delay condition could not be accounted for by the sound cues alone or by executive retrieval processes. Moreover, our results demonstrated evidence of a temporal gradient of interference across experiments. Thus, we propose that rich autobiographical retrieval/future imagination hampers the consolidation of recently acquired episodic memories and that such interference is particularly likely in the presence of external concrete cues.

  20. Neural mechanisms of proactive interference-resolution.

    Science.gov (United States)

    Nee, Derek Evan; Jonides, John; Berman, Marc G

    2007-12-01

    The ability to mitigate interference from information that was previously relevant, but is no longer relevant, is central to successful cognition. Several studies have implicated left ventrolateral prefrontal cortex (VLPFC) as a region tied to this ability, but it is unclear whether this result generalizes across different tasks. In addition, it has been suggested that left anterior prefrontal cortex (APFC) also plays a role in proactive interference-resolution although support for this claim has been limited. The present study used event-related functional magnetic resonance imaging (fMRI) to investigate the role of these regions in resolving proactive-interference across two different tasks performed on the same subjects. Results indicate that both left VLPFC and left APFC are involved in the resolution of proactive interference across tasks. However, different functional networks related to each region suggest dissociable roles for the two regions. Additionally, regions of the posterior cingulate gyrus demonstrated unique involvement in facilitation when short- and long-term memory converged. This pattern of results serves to further specify models of proactive interference-resolution.

  1. General Quantum Interference Principle and Duality Computer

    International Nuclear Information System (INIS)

    Long Guilu

    2006-01-01

    In this article, we propose a general principle of quantum interference for quantum system, and based on this we propose a new type of computing machine, the duality computer, that may outperform in principle both classical computer and the quantum computer. According to the general principle of quantum interference, the very essence of quantum interference is the interference of the sub-waves of the quantum system itself. A quantum system considered here can be any quantum system: a single microscopic particle, a composite quantum system such as an atom or a molecule, or a loose collection of a few quantum objects such as two independent photons. In the duality computer, the wave of the duality computer is split into several sub-waves and they pass through different routes, where different computing gate operations are performed. These sub-waves are then re-combined to interfere to give the computational results. The quantum computer, however, has only used the particle nature of quantum object. In a duality computer, it may be possible to find a marked item from an unsorted database using only a single query, and all NP-complete problems may have polynomial algorithms. Two proof-of-the-principle designs of the duality computer are presented: the giant molecule scheme and the nonlinear quantum optics scheme. We also propose thought experiment to check the related fundamental issues, the measurement efficiency of a partial wave function.

  2. Explaining environmental Kuznets curves. How pollution induces policy and new technology

    International Nuclear Information System (INIS)

    Smulders, S.; Bretschger, L.

    2000-01-01

    Production often causes pollution as a by-product. Once pollution problems become too severe, regulation is introduced by political authorities which forces the economy to make a transition to cleaner production processes. We model this transition as a change in 'general purpose technology' (GPT) and investigate how it interferes with economic growth driven by quality-improvements. The model gives an explanation for the inverted U-shaped relationship found in empirical research for many pollutants, often referred to as the Environmental Kuznets Curve (EKC). We provide an analytical foundation for the claim that the rise and decline of pollution can be explained by policy-induced technology shifts. 19 refs

  3. Iterative Soft Decision Interference Cancellation for DS-CDMA Employing the Distribution of Interference

    Directory of Open Access Journals (Sweden)

    Gerstacker WolfgangH

    2010-01-01

    Full Text Available A well-known receiver strategy for direct-sequence code-division multiple-access (DS-CDMA transmission is iterative soft decision interference cancellation. For calculation of soft estimates used for cancellation, the distribution of residual interference is commonly assumed to be Gaussian. In this paper, we analyze matched filter-based iterative soft decision interference cancellation (MF ISDIC when utilizing an approximation of the actual probability density function (pdf of residual interference. In addition, a hybrid scheme is proposed, which reduces computational complexity by considering the strongest residual interferers according to their pdf while the Gaussian assumption is applied to the weak residual interferers. It turns out that the bit error ratio decreases already noticeably when only a small number of residual interferers is regarded according to their pdf. For the considered DS-CDMA transmission the bit error ratio decreases by 80% for high signal-to-noise ratios when modeling all residual interferers but the strongest three to be Gaussian distributed.

  4. Experimental occlusal interferences. Part IV. Mandibular rotations induced by a pliable interference.

    Science.gov (United States)

    Christensen, L V; Rassouli, N M

    1995-11-01

    In 12 subjects, a pliable, yet unbreakable, intercuspal interference (aluminum shim onlay splint; uniform height of 0.25 mm) was placed between either the right or left maxillary and mandibular second premolars and first molars. During brief and forceful biting (dynamic chewing stroke of about 20 kg force) the interference emulated a semisoft food bolus, and at the end of biting (subsequent static clenching stroke of about 20 kg force) it emulated a rigid metal interference. During dynamic/static biting, rotational electrognathography measured maximum frontal and horizontal plane torque of the right and left mandibular condyles. Eleven subjects (92%) showed frontal plane upward rotation (mean of 1.0 degree) of the condyle contralateral to the interference, and one subject (8%) showed frontal plane upward rotation (0.4 degree) of the condyle ipsilateral to the interference. Two subjects (17%) showed no horizontal plane rotation; seven subjects (58%) showed backward rotation (mean of 0.4 degree) of the condyle contralateral to the interference; and three subjects (25%) showed backward rotation (mean of 0.3 degree) of the condyle ipsilateral to the interference. It is suggested that, in the presence of an occlusal interference, mastication may have both short- and long-term detrimental effects.

  5. Interference Calculus A General Framework for Interference Management and Network Utility Optimization

    CERN Document Server

    Schubert, Martin

    2012-01-01

    This book develops a mathematical framework for modeling and optimizing interference-coupled multiuser systems. At the core of this framework is the concept of general interference functions, which provides a simple means of characterizing interdependencies between users. The entire analysis builds on the two core axioms scale-invariance and monotonicity. The proposed network calculus has its roots in power control theory and wireless communications. It adds theoretical tools for analyzing the typical behavior of interference-coupled networks. In this way it complements existing game-theoretic approaches. The framework should also be viewed in conjunction with optimization theory. There is a fruitful interplay between the theory of interference functions and convex optimization theory. By jointly exploiting the properties of interference functions, it is possible to design algorithms that outperform general-purpose techniques that only exploit convexity. The title “network calculus” refers to the fact tha...

  6. Mitigation of MIMO Co-Channel Interference using robust interference cancellation receiver

    DEFF Research Database (Denmark)

    Rahman, Muhammad Imadur; De Carvalho, Elisabeth; Prasad, Ramjee

    2007-01-01

    (STBC) link may become equivalent to an interfering Spatial Multiplexing (SM) link. Using this knowledge and understanding, we propose an interference cancellation receiver robust to different types of MIMO interferers at cell edge for the Downlink (DL) of cellular systems. The receiver systematically...... performs a multiple symbol processing: this is the appropriate processing when the signal of interest or the signal of interferer is correlated across symbols, which is the case for STBC transmission. We evaluated different link combinations in terms of Signal to Interference and Noise Ratio (SINR......) statistics and Bit Error Rate (BER) performance in cellular Orthogonal Frequency Division Multiple Access (OFDMA) systems. We have found that the proposed multiple-symbol linear interference cancellation receiver performs satisfactorily when any kind of single 'logical' stream MIMO scheme is present...

  7. Time and interference: Effects on working memory.

    Science.gov (United States)

    Botto, Marta; Palladino, Paola

    2016-05-01

    This study tested predictions from the time-based resource-sharing (TBRS) model with a classical verbal working memory (WM) task, where target and non-target information interfere strongly with each other. Different predictions can be formulated according to the dominant perspectives (TBRS and interference hypothesis) on the role of inhibitory control in WM task performance. Here, we aimed to trace the activation of irrelevant information, examining priming effects in a lexical decision task immediately following WM recall. Results indicate the roles of both time and interference constraints in determining task performance. In particular, the role of time available seemed crucial at the highest WM loads (i.e., 3 and 4 memoranda). These were also associated with a higher activation of no-longer-relevant information but, in this case, independently from time available for processing. © 2015 The British Psychological Society.

  8. Autonomy, Competence and Non-interference.

    Science.gov (United States)

    Roberts, Joseph T F

    2017-12-30

    In light of the variety of uses of the term autonomy in recent bioethics literature, in this paper, I suggest that competence, not being as contested, is better placed to play the anti-paternalistic role currently assigned to autonomy. The demonstration of competence, I will argue, can provide individuals with robust spheres of non-interference in which they can pursue their lives in accordance with their own values. This protection from paternalism is achieved by granting individuals rights to non-interference upon demonstration of competence. In this paper, I present a risk-sensitive account of competence as a means of grounding rights to non-interference. On a risk-sensitive account of competence individuals demonstrate their competence by exercising three capacities to the extent necessary to meet a threshold determined by the riskiness of the decision. These three capacities are the capacity to (i) acquire knowledge, (ii) use instrumental rationality, and (iii) form and revise a life plan.

  9. Interference Reduction Selected Measurement Signals of Ships

    Directory of Open Access Journals (Sweden)

    Jan Monieta

    2014-08-01

    Full Text Available The paper presents problems encountered at the signal processing of mechanical values with electric methods. Depending on the measured quantity, the location of the sensors and the analysis frequency band, they are differently interferences. The article presents the results of applying the analysis of parameters of working and accompanying process marine medium speed reciprocating engines in the time, amplitude, frequency domain and wavelet analysis to select a reasonable method. The applied signal acquisition program allows you to perform some analysis of signals in different areas and the transformation of the data to other programs. The ways of interference reducing at various stages of their occurrence and analysis are presented. [b]Keywords[/b]: electrical signals, domain analysis, measurement interference

  10. Multiple functionalities of Ni nanoparticles embedded in carboxymethyl guar gum polymer: catalytic activity and superparamagnetism

    International Nuclear Information System (INIS)

    Sardar, Debasmita; Sengupta, Manideepa; Bordoloi, Ankur; Ahmed, Md. A.; Neogi, S.K.; Bandyopadhyay, Sudipta; Jain, Ruchi; Gopinath, Chinnakonda S.; Bala, Tanushree

    2017-01-01

    Highlights: • Ni nanoparticles were synthesized in polymer to form Ni-Polymer composite. • Ni nanoparticles retain their superparamagnetism in the composite. • Ni-Polymer composites showed catalytic activity. - Abstract: Composites comprising of metallic nanoparticles in polymer matrices have allured significant importance due to multifunctionalities. Here a simple protocol has been described to embed Ni nanoparticles in carboxymethyl guar gum (CMGG) polymer. The composite formation helps in the stabilization of Ni nanoparticles which are otherwise prone towards aerial oxidation. Further the nanoparticles retain their superparamagnetic nature and catalytic capacity. Ni-Polymer composite catalyses the reduction of 4-Nitrophenol to 4-Aminophenol very efficiently in presence of NaBH_4, attaining a complete conversion under some experimental conditions. Ni-Polymer composite is well characterized using UV–vis spectroscopy, FTIR, XPS, powder XRD, TGA, SEM and TEM. A detailed magnetic measurement using superconducting quantum interference device-vibrating sample magnetometer (SQUID-VSM) reveals superparamagnetic behaviour of the composite.

  11. Frequent video game players resist perceptual interference.

    Directory of Open Access Journals (Sweden)

    Aaron V Berard

    Full Text Available Playing certain types of video games for a long time can improve a wide range of mental processes, from visual acuity to cognitive control. Frequent gamers have also displayed generalized improvements in perceptual learning. In the Texture Discrimination Task (TDT, a widely used perceptual learning paradigm, participants report the orientation of a target embedded in a field of lines and demonstrate robust over-night improvement. However, changing the orientation of the background lines midway through TDT training interferes with overnight improvements in overall performance on TDT. Interestingly, prior research has suggested that this effect will not occur if a one-hour break is allowed in between the changes. These results have suggested that after training is over, it may take some time for learning to become stabilized and resilient against interference. Here, we tested whether frequent gamers have faster stabilization of perceptual learning compared to non-gamers and examined the effect of daily video game playing on interference of training of TDT with one background orientation on perceptual learning of TDT with a different background orientation. As a result, we found that non-gamers showed overnight performance improvement only on one background orientation, replicating previous results with the interference in TDT. In contrast, frequent gamers demonstrated overnight improvements in performance with both background orientations, suggesting that they are better able to overcome interference in perceptual learning. This resistance to interference suggests that video game playing not only enhances the amplitude and speed of perceptual learning but also leads to faster and/or more robust stabilization of perceptual learning.

  12. Frequent video game players resist perceptual interference.

    Science.gov (United States)

    Berard, Aaron V; Cain, Matthew S; Watanabe, Takeo; Sasaki, Yuka

    2015-01-01

    Playing certain types of video games for a long time can improve a wide range of mental processes, from visual acuity to cognitive control. Frequent gamers have also displayed generalized improvements in perceptual learning. In the Texture Discrimination Task (TDT), a widely used perceptual learning paradigm, participants report the orientation of a target embedded in a field of lines and demonstrate robust over-night improvement. However, changing the orientation of the background lines midway through TDT training interferes with overnight improvements in overall performance on TDT. Interestingly, prior research has suggested that this effect will not occur if a one-hour break is allowed in between the changes. These results have suggested that after training is over, it may take some time for learning to become stabilized and resilient against interference. Here, we tested whether frequent gamers have faster stabilization of perceptual learning compared to non-gamers and examined the effect of daily video game playing on interference of training of TDT with one background orientation on perceptual learning of TDT with a different background orientation. As a result, we found that non-gamers showed overnight performance improvement only on one background orientation, replicating previous results with the interference in TDT. In contrast, frequent gamers demonstrated overnight improvements in performance with both background orientations, suggesting that they are better able to overcome interference in perceptual learning. This resistance to interference suggests that video game playing not only enhances the amplitude and speed of perceptual learning but also leads to faster and/or more robust stabilization of perceptual learning.

  13. An interference model of visual working memory.

    Science.gov (United States)

    Oberauer, Klaus; Lin, Hsuan-Yu

    2017-01-01

    The article introduces an interference model of working memory for information in a continuous similarity space, such as the features of visual objects. The model incorporates the following assumptions: (a) Probability of retrieval is determined by the relative activation of each retrieval candidate at the time of retrieval; (b) activation comes from 3 sources in memory: cue-based retrieval using context cues, context-independent memory for relevant contents, and noise; (c) 1 memory object and its context can be held in the focus of attention, where it is represented with higher precision, and partly shielded against interference. The model was fit to data from 4 continuous-reproduction experiments testing working memory for colors or orientations. The experiments involved variations of set size, kind of context cues, precueing, and retro-cueing of the to-be-tested item. The interference model fit the data better than 2 competing models, the Slot-Averaging model and the Variable-Precision resource model. The interference model also fared well in comparison to several new models incorporating alternative theoretical assumptions. The experiments confirm 3 novel predictions of the interference model: (a) Nontargets intrude in recall to the extent that they are close to the target in context space; (b) similarity between target and nontarget features improves recall, and (c) precueing-but not retro-cueing-the target substantially reduces the set-size effect. The success of the interference model shows that working memory for continuous visual information works according to the same principles as working memory for more discrete (e.g., verbal) contents. Data and model codes are available at https://osf.io/wgqd5/. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  14. Indoor air pollution

    International Nuclear Information System (INIS)

    Qureshi, I.H.

    2001-01-01

    Indoor air pollution is a potential risk to human health. Prolonged exposure to indoor pollutants may cause various infectious, allergic and other diseases. Indoor pollutants can emanate from a broad array of internal and external sources. Internal sources include building and furnishing materials, consumer and commercial products, office equipment, micro-organisms, pesticides and human occupants activities. External sources include soil, water supplies and outside makeup air. The main indoor air pollutants of concern are inorganic gases, formaldehyde and other volatile organic compounds, pesticides, radon and its daughters, particulates and microbes. The magnitude of human exposure to indoor pollutants can be estimated or predicted with the help of mathematical models which have been developed using the data from source emission testing and field monitoring of pollutants. In order to minimize human exposure to indoor pollutants, many countries have formulated guidelines / standards for the maximum permissible levels of main pollutants. Acceptable indoor air quality can be achieved by controlling indoor pollution sources and by effective ventilation system for removal of indoor pollutants. (author)

  15. LANGUAGE AND CULTURE INTERFERENCE IN PLURILINGUAL EDUCATION

    Directory of Open Access Journals (Sweden)

    Hackett-Jones, A.V.

    2016-09-01

    Full Text Available The article deals with interlingual phenomena that occur in the process of multiple language acquisition in a learning environment. The notions of language interference and transfer put forward by the theories of bilingualism, give useful insights when applied to the modern day educational trends. Language and culture interference is an important aspect to be considered with regard to teaching of plurilingual learners, whose communicative competence is formed on the basis of several linguistic and cultural systems that interact with each other and exert mutual influence.

  16. Graded photonic crystals by optical interference holography

    International Nuclear Information System (INIS)

    Han, Chunrui; Tam, Wing Yim

    2012-01-01

    We report on the fabrication of graded photonic crystals in dye doped dichromate gelatin emulsions using an optical interference holographic technique. The gradedness is achieved by imposing a gradient form factor in the interference intensity resulting from the absorption of the dye in the dichromate gelatin. Wider and deeper photonic bandgaps are observed for the dyed samples as compared to the un-dyed samples. Our method could open up a new direction in fabricating graded photonic crystals which cannot be achieved easily using other techniques. (paper)

  17. Inertial and interference effects in optical spectroscopy

    International Nuclear Information System (INIS)

    Karstens, W; Smith, D Y

    2015-01-01

    Interference between free-space and material components of the displacement current plays a key role in determining optical properties. This is illustrated by an analogy between the Lorentz optical model and a-c circuits. Phase shifts in material-polarization currents, which are inertial, relative to the non-inertial vacuum-polarization current cause interference in the total displacement current and, hence, variation in E-M wave propagation. If the displacement-current is reversed, forward propagation is inhibited yielding the semimetallic reflectivity exhibited by intrinsic silicon. Complete cancellation involves material currents offsetting free-space currents to form current-loops that correspond to plasmons. (paper)

  18. Sensorimotor Interference When Reasoning About Described Environments

    Science.gov (United States)

    Avraamides, Marios N.; Kyranidou, Melina-Nicole

    The influence of sensorimotor interference was examined in two experiments that compared pointing with iconic arrows and verbal responding in a task that entailed locating target-objects from imagined perspectives. Participants studied text narratives describing objects at locations around them in a remote environment and then responded to targets from memory. Results revealed only minor differences between the two response modes suggesting that bodily cues do not exert severe detrimental interference on spatial reasoning from imagined perspective when non-immediate described environments are used. The implications of the findings are discussed.

  19. Hydrocarbons and air pollution

    International Nuclear Information System (INIS)

    Herz, O.

    1992-01-01

    This paper shows the influence of hydrocarbons vapors, emitted by transports or by volatile solvents using, on air pollution. Hydrocarbons are the principal precursors of photochemical pollution. After a brief introduction on atmospheric chemistry and photochemical reactions, the author describes the french prevention program against hydrocarbons emissions. In the last chapter, informations on international or european community programs for photochemical pollution study are given. 5 figs., 10 tabs

  20. Perspective of environmental pollution

    Energy Technology Data Exchange (ETDEWEB)

    Argent, B.B.; Thompson, D. [Sheffield Univ., Dept. of Engineering Materials, Sheffield (United Kingdom); Edyvean, R.G.J. [Sheffield Univ., Dept. of Chemical and Process Engineering, Sheffield (United Kingdom); Spears, D.A. [Sheffield Univ., Dept. of Earth Sciences, Sheffield (United Kingdom)

    2004-04-01

    This article aims to stimulate interest in pollution problems that are associated with the minerals industries. Because this subject is so broad, this study has concentrated on a limited number of topics that have been studied by the authors. After a brief survey indicating major sources of pollution through gaseous emissions, contamination of waterways and land fill sites, attention is focused on some of the methods of predicting, monitoring and limiting emissions together with remediation of polluted sites. (Author)

  1. Air pollution and lichens

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, B W; Baddeley, M S; Hawksworth, D L [eds.

    1973-01-01

    This volume reflects the concern of biologists for the effects of air pollution and illustrates the special values of lichens as plants suitable for such studies. Emphasis is placed on the logical progression from field observational studies to laboratory investigations aimed at elucidating the modes of action of various pollutants. The actions of pollutants on vascular plants is also discussed. Separate analytics are included for 17 chapters.

  2. Light Pollution | CTIO

    Science.gov (United States)

    Preserving the Dark Skies La Oficina de Protección de la Calidad del Cielo del Norte de Chile - OPCC Light ‹› You are here CTIO Home » Outreach » NOAO-S EPO Programs » Dark Sky Education » Light Pollution Light Pollution Preserving Dark Skies: Efforts to measure light pollution and work with the local

  3. Marine Pollution and Ecotoxicology

    Digital Repository Service at National Institute of Oceanography (India)

    Sarkar, A.

    . Heavy metals Editorial Guest The special issue of Environment International has come up with selected papers presented in the International workshop on Marine Pollution and Ecotoxicology held at the National Institute of Oceanography, Dona Paula, Goa... presented in this special issue are classified into five sections namely, Coastal water quality, Heavy metals, Trace metals, Persistent organic pollutants and Ecotoxicology. 1. Coastal water quality assessment The pollution of the marine environment has...

  4. Multiple-Antenna Interference Cancellation for WLAN with MAC Interference Avoidance in Open Access Networks

    Directory of Open Access Journals (Sweden)

    Alexandr M. Kuzminskiy

    2007-10-01

    Full Text Available The potential of multiantenna interference cancellation receiver algorithms for increasing the uplink throughput in WLAN systems such as 802.11 is investigated. The medium access control (MAC in such systems is based on carrier sensing multiple-access with collision avoidance (CSMA/CA, which itself is a powerful tool for the mitigation of intrasystem interference. However, due to the spatial dependence of received signal strengths, it is possible for the collision avoidance mechanism to fail, resulting in packet collisions at the receiver and a reduction in system throughput. The CSMA/CA MAC protocol can be complemented in such scenarios by interference cancellation (IC algorithms at the physical (PHY layer. The corresponding gains in throughput are a result of the complex interplay between the PHY and MAC layers. It is shown that semiblind interference cancellation techniques are essential for mitigating the impact of interference bursts, in particular since these are typically asynchronous with respect to the desired signal burst. Semiblind IC algorithms based on second- and higher-order statistics are compared to the conventional no-IC and training-based IC techniques in an open access network (OAN scenario involving home and visiting users. It is found that the semiblind IC algorithms significantly outperform the other techniques due to the bursty and asynchronous nature of the interference caused by the MAC interference avoidance scheme.

  5. Multiple-Antenna Interference Cancellation for WLAN with MAC Interference Avoidance in Open Access Networks

    Directory of Open Access Journals (Sweden)

    Kuzminskiy Alexandr M

    2007-01-01

    Full Text Available The potential of multiantenna interference cancellation receiver algorithms for increasing the uplink throughput in WLAN systems such as 802.11 is investigated. The medium access control (MAC in such systems is based on carrier sensing multiple-access with collision avoidance (CSMA/CA, which itself is a powerful tool for the mitigation of intrasystem interference. However, due to the spatial dependence of received signal strengths, it is possible for the collision avoidance mechanism to fail, resulting in packet collisions at the receiver and a reduction in system throughput. The CSMA/CA MAC protocol can be complemented in such scenarios by interference cancellation (IC algorithms at the physical (PHY layer. The corresponding gains in throughput are a result of the complex interplay between the PHY and MAC layers. It is shown that semiblind interference cancellation techniques are essential for mitigating the impact of interference bursts, in particular since these are typically asynchronous with respect to the desired signal burst. Semiblind IC algorithms based on second- and higher-order statistics are compared to the conventional no-IC and training-based IC techniques in an open access network (OAN scenario involving home and visiting users. It is found that the semiblind IC algorithms significantly outperform the other techniques due to the bursty and asynchronous nature of the interference caused by the MAC interference avoidance scheme.

  6. Photonic band gap effect and structural color from silver nanoparticle gelatin emulsion

    Science.gov (United States)

    Kok, Mang Hin; Ma, Rui; Lee, Jeffrey Chi Wai; Tam, Wing Yim; Chan, C. T.; Sheng, Ping; Cheah, Kok Wai

    2005-10-01

    We have fabricated planar structures of silver nanoparticles in monochromatic gelatin emulsion with a continuous spacing ranging from 0.15-0.40 micron using a two-beam interference of a single laser source. Our planar holograms display a colorful “rainbow” pattern and photonic bandgaps covering the visible and IR ranges. We model the planar silver nanoparticle-gelatin composite system using an effective medium approach and good agreement is obtained between theory and experiment.

  7. Air pollution meteorology

    Energy Technology Data Exchange (ETDEWEB)

    Shirvaikar, V V; Daoo, V J [Environmental Assessment Div., Bhabha Atomic Research Centre, Mumbai (India)

    2002-06-01

    This report is intended as a training cum reference document for scientists posted at the Environmental Laboratories at the Nuclear Power Station Sites and other sites of the Department of Atomic Energy with installations emitting air pollutants, radioactive or otherwise. Since a manual already exists for the computation of doses from radioactive air pollutants, a general approach is take here i.e. air pollutants in general are considered. The first chapter presents a brief introduction to the need and scope of air pollution dispersion modelling. The second chapter is a very important chapter discussing the aspects of meteorology relevant to air pollution and dispersion modelling. This chapter is important because without this information one really does not understand the phenomena affecting dispersion, the scope and applicability of various models or their limitations under various weather and site conditions. The third chapter discusses the air pollution models in detail. These models are applicable to distances of a few tens of kilometres. The fourth chapter discusses the various aspects of meteorological measurements relevant to air pollution. The chapters are followed by two appendices. Apendix A discusses the reliability of air pollution estimates. Apendix B gives some practical examples relevant to general air pollution. It is hoped that the document will prove very useful to the users. (author)

  8. RNA interference: its use as antiviral therapy

    NARCIS (Netherlands)

    Haasnoot, J.; Berkhout, B.

    2006-01-01

    RNA interference (RNAi) is a sequence-specific gene-silencing mechanism that has been proposed to function as a defence mechanism of eukaryotic cells against viruses and transposons. RNAi was first observed in plants in the form of a mysterious immune response to viral pathogens. But RNAi is more

  9. Resistance to Interference of Olfactory Perceptual Learning

    Science.gov (United States)

    Stevenson, Richard J.; Case, Trevor I.; Tomiczek, Caroline

    2007-01-01

    Olfactory memory is especially persistent. The current study explored whether this applies to a form of perceptual learning, in which experience of an odor mixture results in greater judged similarity between its elements. Experiment 1A contrasted 2 forms of interference procedure, "compound" (mixture AW, followed by presentation of new mixtures…

  10. A slow component of classic Stroop interference

    NARCIS (Netherlands)

    Phaf, R. Hans; Horsman, Hark H.; van der Moolen, Bas; Roos, Yvo B. W. E. M.; Schmand, Ben

    2010-01-01

    The interference in colour naming may extend beyond critical Stroop trials. This "slow'' effect was first discovered in emotional Stroop tasks, but is extended here to classical Stroop. In two experiments, meaningless coloured letter strings followed a colour word or neutral word. Student

  11. Stroop interference and disorders of selective attention

    NARCIS (Netherlands)

    Kingma, A.; LaHeij, W.; Fasotti, L.; Eling, P.

    1996-01-01

    Fourteen patients with a right-hemisphere CVA and 8 patients with a left-hemisphere CVA were examined for selective attention deficits using a variant of the Stroop color-word task: the picture-word interference task. Experiments 1 and 2 first compared the performance of the two patient groups and a

  12. Inhibition of virus replication by RNA interference

    NARCIS (Netherlands)

    Haasnoot, P. C. Joost; Cupac, Daniel; Berkhout, Ben

    2003-01-01

    RNA interference (RNAi) is a sequence-specific gene-silencing mechanism in eukaryotes, which is believed to function as a defence against viruses and transposons. Since its discovery, RNAi has been developed into a widely used technique for generating genetic knock-outs and for studying gene

  13. 47 CFR 74.703 - Interference.

    Science.gov (United States)

    2010-10-01

    ... energy outside its assigned channel. Upon notice by the FCC to the station licensee or operator that such... suspended and not resumed until the interference has been eliminated. However, short test transmissions may... services provided by existing and future commercial or public safety wireless licensees in the 700 MHz...

  14. Generalized quantum interference of correlated photon pairs

    Science.gov (United States)

    Kim, Heonoh; Lee, Sang Min; Moon, Han Seb

    2015-01-01

    Superposition and indistinguishablility between probability amplitudes have played an essential role in observing quantum interference effects of correlated photons. The Hong-Ou-Mandel interference and interferences of the path-entangled photon number state are of special interest in the field of quantum information technologies. However, a fully generalized two-photon quantum interferometric scheme accounting for the Hong-Ou-Mandel scheme and path-entangled photon number states has not yet been proposed. Here we report the experimental demonstrations of the generalized two-photon interferometry with both the interferometric properties of the Hong-Ou-Mandel effect and the fully unfolded version of the path-entangled photon number state using photon-pair sources, which are independently generated by spontaneous parametric down-conversion. Our experimental scheme explains two-photon interference fringes revealing single- and two-photon coherence properties in a single interferometer setup. Using the proposed interferometric measurement, it is possible to directly estimate the joint spectral intensity of a photon pair source. PMID:25951143

  15. Cue-Dependent Interference in Comprehension

    Science.gov (United States)

    Van Dyke, Julie A.; McElree, Brian

    2011-01-01

    The role of interference as a primary determinant of forgetting in memory has long been accepted, however its role as a contributor to poor comprehension is just beginning to be understood. The current paper reports two studies, in which speed-accuracy tradeoff and eye-tracking methodologies were used with the same materials to provide converging…

  16. A model for interference and forgetting

    NARCIS (Netherlands)

    Raaijmakers, J.G.W.; Mensink, G.J.M.A

    1988-01-01

    A new model for interference and forgetting is presented. The model is based on the search of associative memory (SAM) theory for retrieval from long-term memory by J. G. Raaijmakers and R. M. Shiffrin, see record 1981-20491-001). It includes a contextual fluctuation process that enables it to

  17. Preserved Proactive Interference in Autism Spectrum Disorder

    Science.gov (United States)

    Carmo, Joana C.; Duarte, Elsa; Pinho, Sandra; Filipe, Carlos N.; Marques, J. Frederico

    2016-01-01

    In this study, we aimed to evaluate further the functioning and structuring of the semantic system in autism spectrum disorders (ASD). We analyzed the performance of 19 high-functioning young adults with ASD and a group of 20 age-, verbal IQ- and education-matched individuals with the Proactive Interference (PI) Paradigm to evaluate semantic…

  18. Exploiting Genetic Interference for Antiviral Therapy.

    Directory of Open Access Journals (Sweden)

    Elizabeth J Tanner

    2016-05-01

    Full Text Available Rapidly evolving viruses are a major threat to human health. Such viruses are often highly pathogenic (e.g., influenza virus, HIV, Ebola virus and routinely circumvent therapeutic intervention through mutational escape. Error-prone genome replication generates heterogeneous viral populations that rapidly adapt to new selection pressures, leading to resistance that emerges with treatment. However, population heterogeneity bears a cost: when multiple viral variants replicate within a cell, they can potentially interfere with each other, lowering viral fitness. This genetic interference can be exploited for antiviral strategies, either by taking advantage of a virus's inherent genetic diversity or through generating de novo interference by engineering a competing genome. Here, we discuss two such antiviral strategies, dominant drug targeting and therapeutic interfering particles. Both strategies harness the power of genetic interference to surmount two particularly vexing obstacles-the evolution of drug resistance and targeting therapy to high-risk populations-both of which impede treatment in resource-poor settings.

  19. RNA interference in plant parasitic nematodes

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... grower preference or by government restrictions to limit the environmental ... risks associated with chemical control and (c) the pro- vision of ... certain model organisms. The first ... reproductive system (Lilley et al., 2005b), sperm (Urwin .... interference of dual oxidase in the plant nematode Meloidogyne.

  20. Electron Interference in Ballistic Graphene Nanoconstrictions

    DEFF Research Database (Denmark)

    Baringhaus, Jens; Settnes, Mikkel; Aprojanz, Johannes

    2016-01-01

    We realize nanometer size constrictions in ballistic graphene nanoribbons grown on sidewalls of SiC mesa structures. The high quality of our devices allows the observation of a number of electronic quantum interference phenomena. The transmissions of Fabry-Perot-like resonances are probed...

  1. Interference analysis of fission cross section

    International Nuclear Information System (INIS)

    Toshkov, S.A.; Yaneva, N.B.

    1976-01-01

    The formula for the reaction cross-section based on the R-matrix formalism considering the interference between the two neighbouring resonances, referred to the same value of total momentum was used for the analysis of the cross-section of resonance neutron induced fission of 230Pu. The experimental resolution and thermal motion of the target nuclei were accounted for numerical integration

  2. Semantic category interference in overt picture naming

    NARCIS (Netherlands)

    Maess, B.; Friederici, A.D.; Damian, M.F.; Meyer, A.S.; Levelt, W.J.M.

    2002-01-01

    The study investigated the neuronal basis of the retrieval of words from the mental lexicon. The semantic category interference effect was used to locate lexical retrieval processes in time and space. This effect reflects the finding that, for overt naming, volunteers are slower when naming pictures

  3. The Acceptability of Speech with Radio Interference

    DEFF Research Database (Denmark)

    Baykaner, K.; Hummersone, H.; Mason, R.

    2014-01-01

    A listening test was conducted to investigate the acceptability of audio-on-audio interference for radio programs featuring speech as the target. Twenty-one subjects, including naïve and expert listeners, were presented with 200 randomly assigned pairs of stimuli and asked to report, for each trial...

  4. Polarization modulation in Young's interference experiment

    International Nuclear Information System (INIS)

    Tervo, Jani

    2008-01-01

    Polarization properties at the observation screen in Young's interference experiment are examined. Several recent results on the modulation of Stokes parameters, including the minimum number of modulated parameters, are reviewed. The theory is then applied to find out the relation between the Stokes parameters at the pinholes and the Pancharatnam-Berry phase at the screen.

  5. New two-port multimode interference reflectors

    NARCIS (Netherlands)

    Kleijn, E.; Smit, M.K.; Wale, M.J.; Leijtens, X.J.M.

    2012-01-01

    Multi-mode interference reflectors (MIRs) are versatile components. Two new MIR designs with a fixed 50/50 reflection to transmission ratio are introduced. Measurements on these new devices and on devices similar to those in [1] are presented and compared to the design values. Measured losses are

  6. Movement Interference in Autism-Spectrum Disorder

    Science.gov (United States)

    Gowen, E.; Stanley, J.; Miall, R. C.

    2008-01-01

    Movement interference occurs when concurrently observing and executing incompatible actions and is believed to be due to co-activation of conflicting populations of mirror neurons. It has also been suggested that mirror neurons contribute towards the imitation of observed actions. However, the exact neural substrate of imitation may depend on task…

  7. Highly Polluted Wastewaters Treatment by Improved Dissolved Air Flotation Technology

    Science.gov (United States)

    Moga, I. C.; Covaliu, C. I.; Matache, M. G.; Doroftei, B. I.

    2017-06-01

    Numerous investigations are oriented towards the development of new wastewater treatment technologies, having high efficiencies for removing even low concentrations of pollutants found in water. These efforts were determined by the destroyer impact of the pollutants to the environment and human’s health. For this reason this paper presents our study concerning an improved dissolved air flotation technology for wastewater treatment. There is described a dissolved air flotation (DAF) installation composed by two equipments: pressurized capsule and lamellar settling. Also, there are presented some advantages of using nanoparticles as flotation collectors.

  8. Interference effects of categorization on decision making.

    Science.gov (United States)

    Wang, Zheng; Busemeyer, Jerome R

    2016-05-01

    Many decision making tasks in life involve a categorization process, but the effects of categorization on subsequent decision making has rarely been studied. This issue was explored in three experiments (N=721), in which participants were shown a face stimulus on each trial and performed variations of categorization-decision tasks. On C-D trials, they categorized the stimulus and then made an action decision; on X-D trials, they were told the category and then made an action decision; on D-alone trials, they only made an action decision. An interference effect emerged in some of the conditions, such that the probability of an action on the D-alone trials (i.e., when there was no explicit categorization before the decision) differed from the total probability of the same action on the C-D or X-D trials (i.e., when there was explicit categorization before the decision). Interference effects are important because they indicate a violation of the classical law of total probability, which is assumed by many cognitive models. Across all three experiments, a complex pattern of interference effects systematically occurred for different types of stimuli and for different types of categorization-decision tasks. These interference effects present a challenge for traditional cognitive models, such as Markov and signal detection models, but a quantum cognition model, called the belief-action entanglement (BAE) model, predicted that these results could occur. The BAE model employs the quantum principles of superposition and entanglement to explain the psychological mechanisms underlying the puzzling interference effects. The model can be applied to many important and practical categorization-decision situations in life. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Technical Note: Quantification of interferences of wet chemical HONO LOPAP measurements under simulated polar conditions

    Directory of Open Access Journals (Sweden)

    J. Kleffmann

    2008-11-01

    Full Text Available In the present pilot study, an optimized LOPAP instrument (LOng Path Absorption Photometer for the detection of nitrous acid (HONO in the atmosphere (DL 0.2 pptV was tested at the high alpine research station Jungfraujoch at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range <0.5–50 pptV with an average of 7.5 pptV were observed at the Jungfraujoch. The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the active correction of interferences is of paramount importance for the determination of reliable HONO data.

  10. Global chemical pollution

    International Nuclear Information System (INIS)

    Travis, C.C.; Hester, S.T.

    1991-01-01

    Over the past decade, public and governmental awareness of environmental problems has grown steadily, with an accompanying increase in the regulation of point sources of pollution. As a result, great strides have been made in cleaning polluted rivers and decreasing air pollution near factories. However, traditional regulatory approaches to environmental pollution have focused primarily on protecting the maximally exposed individual located in the immediate vicinity of the pollution source. Little attention has been given to the global implications of human production and use of synthetic chemicals. A consensus is emerging that even trace levels of environmental contamination can have potentially devastating environmental consequences. The authors maintain that ambient levels of pollution have risen to the point where human health is being affected on a global scale. Atmospheric transport is recognized as the primary mode of global distribution and entry into the food chain for organic chemicals. The following are examples of global chemical pollutants that result in human exposure of significant proportions: PCBs, dioxins, benzene, mercury and lead. Current regulatory approaches for environmental pollution do not incorporate ways of dealing with global pollution. Instead the major focus has been on protecting the maximally exposed individual. If we do not want to change our standard of living, the only way to reduce global chemical pollution is to make production and consumption processes more efficient and to lower the levels of production of these toxic chemicals. Thus the only reasonable solution to global pollution is not increased regulation of isolated point sources, but rather an increased emphasis on waste reduction and materials recycling. Until we focus on these issues, we will continue to experience background cancer risk in the 10 -3 range

  11. Air pollution engineering

    Science.gov (United States)

    Maduna, Karolina; Tomašić, Vesna

    2017-11-01

    Air pollution is an environmental and a social problem which leads to a multitude of adverse effects on human health and standard of human life, state of the ecosystems and global change of climate. Air pollutants are emitted from natural, but mostly from anthropogenic sources and may be transported over long distances. Some air pollutants are extremely stable in the atmosphere and may accumulate in the environment and in the food chain, affecting human beings, animals and natural biodiversity. Obviously, air pollution is a complex problem that poses multiple challenges in terms of management and abatements of the pollutants emission. Effective approach to the problems of air pollution requires a good understanding of the sources that cause it, knowledge of air quality status and future trends as well as its impact on humans and ecosystems. This chapter deals with the complexities of the air pollution and presents an overview of different technical processes and equipment for air pollution control, as well as basic principles of their work. The problems of air protection as well as protection of other ecosystems can be solved only by the coordinated endeavors of various scientific and engineering disciplines, such as chemistry, physics, biology, medicine, chemical engineering and social sciences. The most important engineering contribution is mostly focused on development, design and operation of equipment for the abatement of harmful emissions into environment.

  12. Outdoor air Pollution

    CSIR Research Space (South Africa)

    Forbes, PBC

    2016-07-01

    Full Text Available This chapter focuses on the air pollutants which are generally found in the troposphere and does not provide detail on specific areas where atmospheric pollutants and atmospheric chemistry may differ from that generally found, such as in the arctic...

  13. Pollution Control Using Ozone

    DEFF Research Database (Denmark)

    2017-01-01

    This invention relates to a method for cleaning air comprising one or more pollutants, the method comprising contacting the air with thermal decompositions products of ozone.......This invention relates to a method for cleaning air comprising one or more pollutants, the method comprising contacting the air with thermal decompositions products of ozone....

  14. The pollution by ozone

    International Nuclear Information System (INIS)

    1997-09-01

    Air pollution by ozone is increasing in spite of several points to reduce it. If the process of ozone formation are complex, the sources of this pollution are well known: first, mobile sources with automobiles (49%), boats , trains and planes (13%), then are following paints and solvents(18%), thermal power plants(11%), and finally industry processing with 5%. (N.C.)

  15. Air Pollution and Industry.

    Science.gov (United States)

    Ross, R. D., Ed.

    This book is an authoritative reference and practical guide designed to help the plant engineer identify and solve industrial air pollution problems in order to be able to meet current air pollution regulations. Prepared under the editorial supervision of an experienced chemical engineer, with each chapter contributed by an expert in his field,…

  16. Pollution and Climate Change

    Science.gov (United States)

    Larr, Allison S.; Neidell, Matthew

    2016-01-01

    Childhood is a particularly sensitive time when it comes to pollution exposure. Allison Larr and Matthew Neidell focus on two atmospheric pollutants--ozone and particulate matter--that can harm children's health in many ways. Ozone irritates the lungs, causing various respiratory symptoms; it can also damage the lung lining or aggravate lung…

  17. Air Pollution Surveillance Systems

    Science.gov (United States)

    Morgan, George B.; And Others

    1970-01-01

    Describes atmospheric data monitoring as part of total airpollution control effort. Summarizes types of gaseous, liquid and solid pollutants and their sources; contrast between urban and rural environmental air quality; instrumentation to identify pollutants; and anticipated new non-wet chemical physical and physiochemical techniques tor cetection…

  18. Dependency-dependent interference: NPI interference, agreement attraction, and global pragmatic inferences

    Directory of Open Access Journals (Sweden)

    Ming eXiang

    2013-10-01

    Full Text Available Previous psycholinguistics studies have shown that when forming a long distance dependency in online processing, the parser sometimes accepts a sentence even though the required grammatical constraints are only partially met. A mechanistic account of how such errors arise sheds light on both the underlying linguistic representations involved and the processing mechanisms that put such representations together. In the current study, we contrast the NPI (negative polarity items interference effect, as shown by the acceptance of an ungrammatical sentence like The bills that democratic senators have voted for will ever become law, with the well-known phenomenon of agreement attraction (The key to the cabinets are…. On the surface, these two types of errors look alike and thereby can be explained as being driven by the same source: similarity based memory interference. However, we argue that the linguistic representations involved in NPI licensing are substantially different from those of subject-verb agreement, and therefore the interference effects in each domain potentially arise from distinct sources. In particular, we show that NPI interference at least partially arises from pragmatic inferences. In a self-paced reading study with an acceptability judgment task, we showed NPI interference was modulated by participants’ general pragmatic communicative skills, as quantified by the Autism-Spectrum Quotient (Baron-Cohen 2001, especially in offline tasks. Participants with more autistic traits were actually less prone to the NPI interference effect than those with fewer autistic traits. This result contrasted with agreement attraction conditions, which were not influenced by individual pragmatic skill differences. We also show that different NPI licensors have distinct interference profiles. We discuss two kinds of interference effects for NPI licensing: memory-retrieval based and pragmatically triggered.

  19. PtPb nanoparticle electrocatalysts: control of activity through synthetic methods

    International Nuclear Information System (INIS)

    Ghosh, Tanushree; Matsumoto, Futoshi; McInnis, Jennifer; Weiss, Marilyn; Abruna, Hector D.; DiSalvo, Francis J.

    2009-01-01

    Solution phase synthesis of intermetallic nanoparticles without using surfactants (for catalytic applications) and subsequent control of size distribution remains a challenge: of growing interest, but not widely explored yet. To understand the questions in the syntheses of Pt containing intermetallic nanoparticles (as electrocatalysts for direct fuel cells) by using sodium naphthalide as the reducing agent, the effects of the Pt precursors' organic ligands were investigated. PtPb syntheses were studied as the model case. In particular, methods that lead to nanoparticles that are independent single crystals are desirable. Platinum acetylacetonate, which is soluble in many organic solvents, has ligands that may interfere less with nanoparticle growth and ordering. Interesting trends, contrary to expectations, were observed when precursors were injected into a reducing agent solution at high temperatures. The presence of acetylacetonate, from the precursor, on the nanoparticles was confirmed by ATR, while SEM imaging showed evidence of morphological changes in the nanoparticles with increasing reaction temperature. A definite relationship between domain size and extent of observed residue (organic material and sodium) present on the particles could be established. By varying post-reaction solvent removal techniques, room temperature crystallization of PtPb nanoparticles was also achieved. Electrochemical activity of the nanoparticles was also much higher than that of nanoparticles synthesized by previous reaction schemes using sodium naphthalide as the reducing agent. Along with the above mentioned techniques, BET, TEM, CBED, SAED, and XRD were used as characterization tools for the prepared nanoparticles.

  20. Air pollution and vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Numata, M

    1975-01-01

    Although the direct effects of each air pollutant have been fairly well studied for specific species of plants used as indicators, studies on the synecological level have not been done. Clement's communities can be used as indicators. The effects of air pollution should be studied as one in a complex of factors. The characteristic features of biological indicators are described in detail with emphasis on applying the results to human beings in polluted environments. The methods of determining the effects of pollution are described, using a community phytometer and remote sensing methods. Directly connecting the level of air pollution to the wilting of trees in general is dangerous unless it is a matter of an acute episode.

  1. Aircraft engine pollution reduction.

    Science.gov (United States)

    Rudey, R. A.

    1972-01-01

    The effect of engine operation on the types and levels of the major aircraft engine pollutants is described and the major factors governing the formation of these pollutants during the burning of hydrocarbon fuel are discussed. Methods which are being explored to reduce these pollutants are discussed and their application to several experimental research programs are pointed out. Results showing significant reductions in the levels of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen obtained from experimental combustion research programs are presented and discussed to point out potential application to aircraft engines. An experimental program designed to develop and demonstrate these and other advanced, low pollution combustor design methods is described. Results that have been obtained to date indicate considerable promise for reducing advanced engine exhaust pollutants to levels significantly below current engines.

  2. The Approximate Capacity Region of the Symmetric $K$-user Gaussian Interference Channel with Strong Interference

    KAUST Repository

    Chaaban, Anas; Sezgin, Aydin

    2016-01-01

    The symmetric K-user interference channel is studied with the goal of characterizing its capacity region in the strong interference regime within a constant gap. The achievable rate region of a scheme combining rate-splitting at the transmitters and interference alignment and successive decoding/computation at the receivers is derived. Next it is shown that this scheme achieves the so-called greedy-max corner points of the capacity region within a constant gap. By combining this result with previous results by Ordentlich et al. on the sum-capacity of the symmetric interference channel, a constant gap characterization of the capacity region for the strong interference regime is obtained. This leads to the first approximate characterization of the capacity region of the symmetric K-user IC. Furthermore, a new scheme that achieves the sum-capacity of the channel in the strong interference regime within a constant gap is also proposed, and the corresponding gap is calculated. The advantage of the new scheme is that it leads to a characterization within a constant gap without leaving an outage set contrary to the scheme by Ordentlich et al..

  3. (Sub-)Optimality of Treating Interference as Noise in the Cellular Uplink With Weak Interference

    KAUST Repository

    Gherekhloo, Soheil; Chaaban, Anas; Di, Chen; Sezgin, Aydin

    2015-01-01

    Despite the simplicity of the scheme of treating interference as noise (TIN), it was shown to be sum-capacity optimal in the Gaussian interference channel (IC) with very-weak (noisy) interference. In this paper, the two-user IC is altered by introducing an additional transmitter that wants to communicate with one of the receivers of the IC. The resulting network thus consists of a point-to-point channel interfering with a multiple access channel (MAC) and is denoted by PIMAC. The sum-capacity of the PIMAC is studied with main focus on the optimality of TIN. It turns out that TIN in its naive variant, where all transmitters are active and both receivers use TIN for decoding, is not the best choice for the PIMAC. In fact, a scheme that combines both time division multiple access and TIN (TDMA-TIN) strictly outperforms the naive-TIN scheme. Furthermore, it is shown that in some regimes, TDMA-TIN achieves the sum-capacity for the deterministic PIMAC and the sum-capacity within a constant gap for the Gaussian PIMAC. In addition, it is shown that, even for very-weak interference, there are some regimes where a combination of interference alignment with power control and TIN at the receiver side outperforms TDMA-TIN. As a consequence, on the one hand, TIN in a cellular uplink is approximately optimal in certain regimes. On the other hand, those regimes cannot be simply described by the strength of interference.

  4. The Approximate Capacity Region of the Symmetric $K$-user Gaussian Interference Channel with Strong Interference

    KAUST Repository

    Chaaban, Anas

    2016-03-01

    The symmetric K-user interference channel is studied with the goal of characterizing its capacity region in the strong interference regime within a constant gap. The achievable rate region of a scheme combining rate-splitting at the transmitters and interference alignment and successive decoding/computation at the receivers is derived. Next it is shown that this scheme achieves the so-called greedy-max corner points of the capacity region within a constant gap. By combining this result with previous results by Ordentlich et al. on the sum-capacity of the symmetric interference channel, a constant gap characterization of the capacity region for the strong interference regime is obtained. This leads to the first approximate characterization of the capacity region of the symmetric K-user IC. Furthermore, a new scheme that achieves the sum-capacity of the channel in the strong interference regime within a constant gap is also proposed, and the corresponding gap is calculated. The advantage of the new scheme is that it leads to a characterization within a constant gap without leaving an outage set contrary to the scheme by Ordentlich et al..

  5. (Sub-)Optimality of Treating Interference as Noise in the Cellular Uplink With Weak Interference

    KAUST Repository

    Gherekhloo, Soheil

    2015-11-09

    Despite the simplicity of the scheme of treating interference as noise (TIN), it was shown to be sum-capacity optimal in the Gaussian interference channel (IC) with very-weak (noisy) interference. In this paper, the two-user IC is altered by introducing an additional transmitter that wants to communicate with one of the receivers of the IC. The resulting network thus consists of a point-to-point channel interfering with a multiple access channel (MAC) and is denoted by PIMAC. The sum-capacity of the PIMAC is studied with main focus on the optimality of TIN. It turns out that TIN in its naive variant, where all transmitters are active and both receivers use TIN for decoding, is not the best choice for the PIMAC. In fact, a scheme that combines both time division multiple access and TIN (TDMA-TIN) strictly outperforms the naive-TIN scheme. Furthermore, it is shown that in some regimes, TDMA-TIN achieves the sum-capacity for the deterministic PIMAC and the sum-capacity within a constant gap for the Gaussian PIMAC. In addition, it is shown that, even for very-weak interference, there are some regimes where a combination of interference alignment with power control and TIN at the receiver side outperforms TDMA-TIN. As a consequence, on the one hand, TIN in a cellular uplink is approximately optimal in certain regimes. On the other hand, those regimes cannot be simply described by the strength of interference.

  6. O3 Nanoparticles

    KAUST Repository

    Wang, Juan; Li, Yangyang; Deng, Lin; Wei, Nini; Weng, Yakui; Dong, Shuai; Qi, Dianpeng; Qiu, Jun; Chen, Xiaodong; Wu, Tao

    2016-01-01

    Ti2O3 nanoparticles with high performance of photothermal conversion are demonstrated for the first time. Benefiting from the nanosize and narrow-bandgap features, the Ti2O3 nanoparticles possess strong light absorption and nearly 100% internal

  7. Assessment of functional changes in nanoparticle-exposed neuroendocrine cells with amperometry: exploring the generalizability of nanoparticle-vesicle matrix interactions.

    Science.gov (United States)

    Love, Sara A; Haynes, Christy L

    2010-09-01

    Using two of the most commonly synthesized noble metal nanoparticle preparations, citrate-reduced Au and Ag, the impacts of short-term accidental nanoparticle exposure are examined in primary culture murine adrenal medullary chromaffin cells. Transmission electron microscopy (TEM), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Alamar Blue viability studies revealed that nanoparticles are taken up by cells but do not decrease cell viability within 48 hours of exposure. Carbon-fiber microelectrode amperometry (CFMA) examination of exocytosis in nanoparticle-exposed cells revealed that nanoparticle exposure does lead to decreased secretion of chemical messenger molecules, of up to 32.5% at 48 hours of Au exposure. The kinetics of intravesicular species liberation also slows after nanoparticle exposure, between 30 and 50% for Au and Ag, respectively. Repeated stimulation of exocytosis demonstrated that these effects persisted during subsequent stimulations, meaning that nanoparticles do not interfere directly with the vesicle recycling machinery but also that cellular function is unable to recover following vesicle content expulsion. By comparing these trends with parallel studies done using mast cells, it is clear that similar exocytosis perturbations occur across cell types following noble metal nanoparticle exposure, supporting a generalizable effect of nanoparticle-vesicle interactions.

  8. Health Effects of Air Pollution

    Science.gov (United States)

    ... Health effects of air pollution Health effects of air pollution Breathing air that is not clean can hurt ... important to know about the health effects that air pollution can have on you and others. Once you ...

  9. Nanoscale surface characterization using laser interference microscopy

    Science.gov (United States)

    Ignatyev, Pavel S.; Skrynnik, Andrey A.; Melnik, Yury A.

    2018-03-01

    Nanoscale surface characterization is one of the most significant parts of modern materials development and application. The modern microscopes are expensive and complicated tools, and its use for industrial tasks is limited due to laborious sample preparation, measurement procedures, and low operation speed. The laser modulation interference microscopy method (MIM) for real-time quantitative and qualitative analysis of glass, metals, ceramics, and various coatings has a spatial resolution of 0.1 nm for vertical and up to 100 nm for lateral. It is proposed as an alternative to traditional scanning electron microscopy (SEM) and atomic force microscopy (AFM) methods. It is demonstrated that in the cases of roughness metrology for super smooth (Ra >1 nm) surfaces the application of a laser interference microscopy techniques is more optimal than conventional SEM and AFM. The comparison of semiconductor test structure for lateral dimensions measurements obtained with SEM and AFM and white light interferometer also demonstrates the advantages of MIM technique.

  10. Quasiparticle Interference Studies of Quantum Materials.

    Science.gov (United States)

    Avraham, Nurit; Reiner, Jonathan; Kumar-Nayak, Abhay; Morali, Noam; Batabyal, Rajib; Yan, Binghai; Beidenkopf, Haim

    2018-06-03

    Exotic electronic states are realized in novel quantum materials. This field is revolutionized by the topological classification of materials. Such compounds necessarily host unique states on their boundaries. Scanning tunneling microscopy studies of these surface states have provided a wealth of spectroscopic characterization, with the successful cooperation of ab initio calculations. The method of quasiparticle interference imaging proves to be particularly useful for probing the dispersion relation of the surface bands. Herein, how a variety of additional fundamental electronic properties can be probed via this method is reviewed. It is demonstrated how quasiparticle interference measurements entail mesoscopic size quantization and the electronic phase coherence in semiconducting nanowires; helical spin protection and energy-momentum fluctuations in a topological insulator; and the structure of the Bloch wave function and the relative insusceptibility of topological electronic states to surface potential in a topological Weyl semimetal. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Semiconductor laser using multimode interference principle

    Science.gov (United States)

    Gong, Zisu; Yin, Rui; Ji, Wei; Wu, Chonghao

    2018-01-01

    Multimode interference (MMI) structure is introduced in semiconductor laser used in optical communication system to realize higher power and better temperature tolerance. Using beam propagation method (BPM), Multimode interference laser diode (MMI-LD) is designed and fabricated in InGaAsP/InP based material. As a comparison, conventional semiconductor laser using straight single-mode waveguide is also fabricated in the same wafer. With a low injection current (about 230 mA), the output power of the implemented MMI-LD is up to 2.296 mW which is about four times higher than the output power of the conventional semiconductor laser. The implemented MMI-LD exhibits stable output operating at the wavelength of 1.52 μm and better temperature tolerance when the temperature varies from 283.15 K to 293.15 K.

  12. Adaptive transmit selection with interference suppression

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-01-01

    This paper studies the performance of adaptive transmit channel selection in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to- interference-plus- noise ratios (SINRs). Two interference cancelation algorithms, which are the dominant cancelation and the less complex arbitrary cancelation, are considered, for which the receive antenna array is assumed to have small angular spread. Analytical formulation for some performance measures in addition to several processing complexity and numerical comparisons between various adaptation schemes are presented. ©2010 IEEE.

  13. BiVO4 nanoparticles: Preparation, characterization and photocatalytic activity

    Directory of Open Access Journals (Sweden)

    Venkataraman Sivakumar

    2015-12-01

    Full Text Available Bismuth vanadate (BiVO4 nanoparticles were synthesized by a simple thermal decomposition method. The synthesized bismuth vanadate nanoparticles were characterized by X-ray diffraction analysis, it is found that the synthesized sample belongs to monoclinic BiVO4. Fourier transform infrared spectroscopy confirms the formation of Bi-O bond in the sample. Ultraviolet–Visible (DRS-UV–Visible spectroscopy and photoluminescence spectroscopy reveal the optical property of the BiVO4 nanoparticles. The morphology was identified by both scanning electron microscopy and high-resolution transmission electron microscopy. Further, the photocatalytic activity of BiVO4 nanoparticles was investigated by photodegradation of methylene blue as a model organic pollutant.

  14. Air pollution modifies floral scent trails

    Science.gov (United States)

    McFrederick, Quinn S.; Kathilankal, James C.; Fuentes, Jose D.

    Floral hydrocarbons provide essential signals to attract pollinators. As soon as they are emitted to the atmosphere, however, hydrocarbons are destroyed by chemical reactions involving pollutants such as ozone. It is therefore likely that increased air pollution interferes with pollinator attracting hydrocarbon signals. To test this hypothesis, a Lagrangian diffusion model was used to determine the position of air parcels away from hydrocarbon sources and to estimate the rate of chemical destruction of hydrocarbons as air parcels moved across the landscape. The hydrocarbon compounds linalool, β-myrcene, and β-ocimene were chosen because they are known to be common scents released from flowers. The suppressed ambient abundances of volatile organic compounds were determined in response to increased regional levels of ozone, hydroxyl, and nitrate radicals. The results indicate that the documented increases in air pollution concentrations, from pre-industrial to present times, can lead to reductions in volatile compound concentrations insects detect as they pollinate flowers. For highly reactive volatiles the maximum downwind distance from the source at which pollinators can detect the scents may have changed from kilometers during pre-industrial times to scent signals may mean that pollinators spend more time searching for patches and less time foraging. This decrease in pollinator foraging efficiency will simultaneously decrease the pollinator's reproductive output and the amount of pollen flow in flowering plants.

  15. Autonomy, Competence and Non-interference

    OpenAIRE

    Roberts, Joseph T.F.

    2017-01-01

    In light of the variety of uses of the term autonomy in recent bioethics literature, in this paper, I suggest that competence, not being as contested, is better placed to play the anti-paternalistic role currently assigned to autonomy. The demonstration of competence, I will argue, can provide individuals with robust spheres of non-interference in which they can pursue their lives in accordance with their own values. This protection from paternalism is achieved by granting individuals rights ...

  16. Angularly resolved electron wave packet interferences

    International Nuclear Information System (INIS)

    Varju, K; Johnsson, P; Mauritsson, J; Remetter, T; Ruchon, T; Ni, Y; Lepine, F; Kling, M; Khan, J; Schafer, K J; Vrakking, M J J; L'Huillier, A

    2006-01-01

    We study experimentally the ionization of argon atoms by a train of attosecond pulses in the presence of a strong infrared laser field, using a velocity map imaging technique. The recorded momentum distribution strongly depends on the delay between the attosecond pulses and the laser field. We interpret the interference patterns observed for different delays using numerical and analytical calculations within the strong field approximation

  17. Angularly resolved electron wave packet interferences

    Energy Technology Data Exchange (ETDEWEB)

    Varju, K [Department of Physics, Lund University, PO Box 118, SE-221 00 Lund (Sweden); Johnsson, P [Department of Physics, Lund University, PO Box 118, SE-221 00 Lund (Sweden); Mauritsson, J [Department of Physics, Lund University, PO Box 118, SE-221 00 Lund (Sweden); Remetter, T [Department of Physics, Lund University, PO Box 118, SE-221 00 Lund (Sweden); Ruchon, T [Department of Physics, Lund University, PO Box 118, SE-221 00 Lund (Sweden); Ni, Y [FOM-Institute AMOLF, Kruislaan 407, 1098 SJ Amsterdam (Netherlands); Lepine, F [FOM-Institute AMOLF, Kruislaan 407, 1098 SJ Amsterdam (Netherlands); Kling, M [FOM-Institute AMOLF, Kruislaan 407, 1098 SJ Amsterdam (Netherlands); Khan, J [FOM-Institute AMOLF, Kruislaan 407, 1098 SJ Amsterdam (Netherlands); Schafer, K J [Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803-4001 (United States); Vrakking, M J J [FOM-Institute AMOLF, Kruislaan 407, 1098 SJ Amsterdam (Netherlands); L' Huillier, A [Department of Physics, Lund University, PO Box 118, SE-221 00 Lund (Sweden)

    2006-09-28

    We study experimentally the ionization of argon atoms by a train of attosecond pulses in the presence of a strong infrared laser field, using a velocity map imaging technique. The recorded momentum distribution strongly depends on the delay between the attosecond pulses and the laser field. We interpret the interference patterns observed for different delays using numerical and analytical calculations within the strong field approximation.

  18. Attosecond interference control of XUV photoionization

    Energy Technology Data Exchange (ETDEWEB)

    Cao Wei; Lu Peixiang; Lan Pengfei; Li Yuhua; Wang Xinlin [Wuhan National Laboratory for Optoelectronics and School of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)], E-mail: lupeixiang@mail.hust.edu.cn

    2008-04-28

    The characterizing of attosecond pulses has great importance for the investigation of ultrafast phenomena. Here, we proposed a novel and efficient scheme for measuring attosecond XUV pulses, which is based on laser-dressed XUV photoionization. The ultrashort attosecond gating of photoionization leads to an interference structure in the photoelectron spectrum. Then the duration of the attosecond XUV pulse can be retrieved directly from the photoelectron spectrum with a rather high resolution.

  19. Attosecond interference control of XUV photoionization

    International Nuclear Information System (INIS)

    Cao Wei; Lu Peixiang; Lan Pengfei; Li Yuhua; Wang Xinlin

    2008-01-01

    The characterizing of attosecond pulses has great importance for the investigation of ultrafast phenomena. Here, we proposed a novel and efficient scheme for measuring attosecond XUV pulses, which is based on laser-dressed XUV photoionization. The ultrashort attosecond gating of photoionization leads to an interference structure in the photoelectron spectrum. Then the duration of the attosecond XUV pulse can be retrieved directly from the photoelectron spectrum with a rather high resolution

  20. Quasiparticle Interference on Cubic Perovskite Oxide Surfaces.

    Science.gov (United States)

    Okada, Yoshinori; Shiau, Shiue-Yuan; Chang, Tay-Rong; Chang, Guoqing; Kobayashi, Masaki; Shimizu, Ryota; Jeng, Horng-Tay; Shiraki, Susumu; Kumigashira, Hiroshi; Bansil, Arun; Lin, Hsin; Hitosugi, Taro

    2017-08-25

    We report the observation of coherent surface states on cubic perovskite oxide SrVO_{3}(001) thin films through spectroscopic-imaging scanning tunneling microscopy. A direct link between the observed quasiparticle interference patterns and the formation of a d_{xy}-derived surface state is supported by first-principles calculations. We show that the apical oxygens on the topmost VO_{2} plane play a critical role in controlling the coherent surface state via modulating orbital state.

  1. Destructive quantum interference in spin tunneling problems

    OpenAIRE

    von Delft, Jan; Henley, Christopher L.

    1992-01-01

    In some spin tunneling problems, there are several different but symmetry-related tunneling paths that connect the same initial and final configurations. The topological phase factors of the corresponding tunneling amplitudes can lead to destructive interference between the different paths, so that the total tunneling amplitude is zero. In the study of tunneling between different ground state configurations of the Kagom\\'{e}-lattice quantum Heisenberg antiferromagnet, this occurs when the spi...

  2. Proactive interference effects on sentence production

    OpenAIRE

    FERREIRA, VICTOR S.; FIRATO, CARLA E.

    2002-01-01

    Proactive interference refers to recall difficulties caused by prior similar memory-related processing. Information-processing approaches to sentence production predict that retrievability affects sentence form: Speakers may word sentences so that material that is difficult to retrieve is spoken later. In this experiment, speakers produced sentence structures that could include an optional that, thereby delaying the mention of a subsequent noun phrase. This subsequent noun phrase was either (...

  3. O3 Nanoparticles

    KAUST Repository

    Wang, Juan

    2016-11-16

    Ti2O3 nanoparticles with high performance of photothermal conversion are demonstrated for the first time. Benefiting from the nanosize and narrow-bandgap features, the Ti2O3 nanoparticles possess strong light absorption and nearly 100% internal solar–thermal conversion efficiency. Furthermore, Ti2O3 nanoparticle-based thin film shows potential use in seawater desalination and purification.

  4. Readout of the atomtronic quantum interference device

    Science.gov (United States)

    Haug, Tobias; Tan, Joel; Theng, Mark; Dumke, Rainer; Kwek, Leong-Chuan; Amico, Luigi

    2018-01-01

    A Bose-Einstein condensate confined in ring shaped lattices interrupted by a weak link and pierced by an effective magnetic flux defines the atomic counterpart of the superconducting quantum interference device: the atomtronic quantum interference device (AQUID). In this paper, we report on the detection of current states in the system through a self-heterodyne protocol. Following the original proposal of the NIST and Paris groups, the ring-condensate many-body wave function interferes with a reference condensate expanding from the center of the ring. We focus on the rf AQUID which realizes effective qubit dynamics. Both the Bose-Hubbard and Gross-Pitaevskii dynamics are studied. For the Bose-Hubbard dynamics, we demonstrate that the self-heterodyne protocol can be applied, but higher-order correlations in the evolution of the interfering condensates are measured to readout of the current states of the system. We study how states with macroscopic quantum coherence can be told apart analyzing the noise in the time of flight of the ring condensate.

  5. Immunizing digital systems against electromagnetic interference

    International Nuclear Information System (INIS)

    Ewing, P.D.; Korsah, K.; Antonescu, C.

    1993-01-01

    This paper discusses the development of the technical basis for acceptance criteria applicable to the immunization of digital systems against electromagnetic interference (EMI). The work is sponsored by the US Nuclear Regulatory Commission and stems from the safety-related issues that need to be addressed as a result of the application of digital instrumentation and control systems in nuclear power plants. Designers of digital circuits are incorporating increasingly higher clock frequencies and lower logic level voltages, thereby leading to potentially greater susceptibility of spurious interference being misinterpreted as legitimate logic. Development of the technical basis for acceptance criteria to apply to these digital systems centers around establishing good engineering practices to ensure that sufficient levels of electromagnetic compatibility (EMC) are maintained between the nuclear power plant's electronic and electromechanical systems. First, good EMC design and installation practices are needed to control the emissions from interference sources and thereby their impact on other nearby circuits and systems. Second, a test and evaluation program is needed to outline the EMI tests to be performed, the associated test methods to be followed, and adequate test limits to ensure that the circuit or system under test meets the recommended guidelines. Test and evaluation should be followed by periodic maintenance to assess whether the recommended EMI control practices continue to be adhered to as part of the routine operation of the nuclear power plant. By following these steps, the probability of encountering safety-related instrumentation problems associated with EMI will be greatly reduced

  6. A Decentralized Receiver in Gaussian Interference

    Directory of Open Access Journals (Sweden)

    Christian D. Chapman

    2018-04-01

    Full Text Available Bounds are developed on the maximum communications rate between a transmitter and a fusion node aided by a cluster of distributed receivers with limited resources for cooperation, all in the presence of an additive Gaussian interferer. The receivers cannot communicate with one another and can only convey processed versions of their observations to the fusion center through a Local Array Network (LAN with limited total throughput. The effectiveness of each bound’s approach for mitigating a strong interferer is assessed over a wide range of channels. It is seen that, if resources are shared effectively, even a simple quantize-and-forward strategy can mitigate an interferer 20 dB stronger than the signal in a diverse range of spatially Ricean channels. Monte-Carlo experiments for the bounds reveal that, while achievable rates are stable when varying the receiver’s observed scattered-path to line-of-sight signal power, the receivers must adapt how they share resources in response to this change. The bounds analyzed are proven to be achievable and are seen to be tight with capacity when LAN resources are either ample or limited.

  7. Optical image hiding based on interference

    Science.gov (United States)

    Zhang, Yan; Wang, Bo

    2009-11-01

    Optical image processing has been paid a lot of attentions recently due to its large capacitance and fast speed. Many image encryption and hiding technologies have been proposed based on the optical technology. In conventional image encryption methods, the random phase masks are usually used as encryption keys to encode the images into random white noise distribution. However, this kind of methods requires interference technology such as holography to record complex amplitude. Furthermore, it is vulnerable to attack techniques. The image hiding methods employ the phase retrieve algorithm to encode the images into two or more phase masks. The hiding process is carried out within a computer and the images are reconstructed optically. But the iterative algorithms need a lot of time to hide the image into the masks. All methods mentioned above are based on the optical diffraction of the phase masks. In this presentation, we will propose a new optical image hiding method based on interference. The coherence lights pass through two phase masks and are combined by a beam splitter. Two beams interfere with each other and the desired image appears at the pre-designed plane. Two phase distribution masks are designed analytically; therefore, the hiding speed can be obviously improved. Simulation results are carried out to demonstrate the validity of the new proposed methods.

  8. Visual working memory capacity and proactive interference.

    Science.gov (United States)

    Hartshorne, Joshua K

    2008-07-23

    Visual working memory capacity is extremely limited and appears to be relatively immune to practice effects or the use of explicit strategies. The recent discovery that visual working memory tasks, like verbal working memory tasks, are subject to proactive interference, coupled with the fact that typical visual working memory tasks are particularly conducive to proactive interference, suggests that visual working memory capacity may be systematically under-estimated. Working memory capacity was probed behaviorally in adult humans both in laboratory settings and via the Internet. Several experiments show that although the effect of proactive interference on visual working memory is significant and can last over several trials, it only changes the capacity estimate by about 15%. This study further confirms the sharp limitations on visual working memory capacity, both in absolute terms and relative to verbal working memory. It is suggested that future research take these limitations into account in understanding differences across a variety of tasks between human adults, prelinguistic infants and nonlinguistic animals.

  9. Visual working memory capacity and proactive interference.

    Directory of Open Access Journals (Sweden)

    Joshua K Hartshorne

    Full Text Available BACKGROUND: Visual working memory capacity is extremely limited and appears to be relatively immune to practice effects or the use of explicit strategies. The recent discovery that visual working memory tasks, like verbal working memory tasks, are subject to proactive interference, coupled with the fact that typical visual working memory tasks are particularly conducive to proactive interference, suggests that visual working memory capacity may be systematically under-estimated. METHODOLOGY/PRINCIPAL FINDINGS: Working memory capacity was probed behaviorally in adult humans both in laboratory settings and via the Internet. Several experiments show that although the effect of proactive interference on visual working memory is significant and can last over several trials, it only changes the capacity estimate by about 15%. CONCLUSIONS/SIGNIFICANCE: This study further confirms the sharp limitations on visual working memory capacity, both in absolute terms and relative to verbal working memory. It is suggested that future research take these limitations into account in understanding differences across a variety of tasks between human adults, prelinguistic infants and nonlinguistic animals.

  10. Immunizing digital systems against electromagnetic interference

    International Nuclear Information System (INIS)

    Ewing, P.D.; Korsah, K.; Antonescu, C.

    1993-01-01

    This paper discusses the development of the technical basis for acceptance criteria applicable to the immunization of digital systems against electromagnetic interference (EMI). The work is sponsored by the US Nuclear Regulatory Commission and stems from the safety-related issues that need to be addressed as a result of the application of digital instrumentation and control systems in nuclear power plants. Designers of digital circuits are incorporating increasingly higher clock frequencies and lower logic level voltages, thereby leading to potentially greater susceptibility of spurious interference being misinterpreted as legitimate logic. Development of the technical basis for acceptance criteria to apply to these digital systems centers around establishing good engineering practices to ensure that sufficient levels of electromagnetic compatibility (EMC) are maintained between the nuclear power plant's electronic and electromechanical systems. First, good EMC design and installation practices are needed to control the emissions from interference sources and thereby their impact on other nearby circuits and systems. Secondly, a test and evaluation program is needed to outline the EMI tests to be performed, the associated test methods to be followed, and adequate test limits to ensure that the circuit or system under test meets the recommended guidelines. Test and evaluation should be followed by periodic maintenance to assess whether the recommended EMI control practices continue to be adhered to as part of the routine operation of the nuclear power plant. By following these steps, the probability of encountering safety-related instrumentation problems associated with EMI will be greatly reduced

  11. Interference in wireless ad hoc networks with smart antennas

    KAUST Repository

    Alabdulmohsin, Ibrahim

    2014-01-01

    In this paper, we show that the use of directional antennas in wireless ad hoc networks can actually increase interference due to limitations of virtual carrier sensing. We derive a simple mathematical expression for interference in both physical

  12. Cooperation for Interference Management: A GDoF Perspective

    KAUST Repository

    Gherekhloo, Soheil; Chaaban, Anas; Sezgin, Aydin

    2016-01-01

    The impact of cooperation on interference management is investigated by studying an elemental wireless network, the so-called symmetric interference relay channel (IRC), from a generalized degrees of freedom (GDoF) perspective. This is motivated

  13. Imperfect generalized transmit beamforming with co-channel interference cancelation

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh; Alouini, Mohamed-Slim

    2010-01-01

    of outdated statistical ordering of the interferers instantaneous powers on the effectiveness of dominant interference cancelation is investigated against the less complex adaptive arbitrary cancelation scheme. For the system models described above, new exact

  14. On full duplex Gaussian relay channels with self-interference

    KAUST Repository

    Behboodi, Arash; Chaaban, Anas; Mathar, Rudolf; Alouini, Mohamed-Slim

    2016-01-01

    Self interference (SI) in full duplex (FD) systems is the interference caused by the transmission stream on the reception stream. Being one of the main restrictive factors for performance of practical full duplex systems, however, not too much

  15. The Cost of Learning: Interference Effects in Memory Development

    Science.gov (United States)

    Darby, Kevin P.; Sloutsky, Vladimir M.

    2015-01-01

    Learning often affects future learning and memory for previously learned information by exerting either facilitation or interference effects. Several theoretical accounts of interference effects have been proposed, each making different developmental predictions. This research examines interference effects across development, with the goal of better understanding mechanisms of interference and of memory development. Preschool-aged children and adults participated in a three-phased associative learning paradigm containing stimuli that were either unique or repeated across phases. Both age groups demonstrated interference effects, but only for repeated items. Whereas proactive interference effects were comparable across age groups, retroactive interference reached catastrophic-like levels in children. Additionally, retroactive interference increased in adults when contextual differences between phases were minimized (Experiment 2), and decreased in adults who were more successful at encoding repeated pairs of stimuli during a training phase (Experiment 3). These results are discussed with respect to theories of memory and memory development. PMID:25688907

  16. Release from Proactive Interference: Insufficiency of an Attentional Account

    Science.gov (United States)

    MacLeod, Colin M.

    1975-01-01

    If an attentional cue affects retroactive interference, perhaps a similar mechanism underlies release from proactive interference. This study tested this hypothesis by inserting an attentional cue before the final trial in Wickens' paradigm. (Author/RK)

  17. Interference-aware random beam selection for spectrum sharing systems

    KAUST Repository

    Abdallah, Mohamed M.; Sayed, Mostafa M.; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

    2012-01-01

    . In this paper, we develop interference-aware random beam selection schemes that provide enhanced throughput for the secondary link under the condition that the interference observed at the primary link is within a predetermined acceptable value. For a secondary

  18. Continuous Correctness of Business Processes Against Process Interference

    NARCIS (Netherlands)

    van Beest, Nick; Bucur, Doina

    2013-01-01

    In distributed business process support environments, process interference from multiple stakeholders may cause erroneous process outcomes. Existing solutions to detect and correct interference at runtime employ formal verification and the automatic generation of intervention processes at runtime.

  19. Environmental pollution by petroleum

    Energy Technology Data Exchange (ETDEWEB)

    Murata, T

    1974-06-01

    Pollution causes, cases, and remedies at various stages of petroleum production and usage are reviewed. Petroleum extraction (off-shore drilling and Arctic drilling) can be accompanied by mishaps. In 1971, IMCO (an international safety committee) proposed the partitioning of oil tanker holds into smaller compartments to minimize spillage in case of disaster. Although the solubility of oil in waste water from refineries is reckoned by ppM, the total amount dissolved is not negligible. Petroleum storage and transport on land is complicated by problems of safety in terms of population density as well as by pollution problems. Petroleum end-products such as plastic trash and automobile exhausts contribute to pollution. The role of aldehydes and peroxides in photochemical smog formation must be investigated further. Proper treatment of pollution at each specific point of occurrence, rather than at the end of a production line is recommended. Pollutant concentration for treatment, rather than pollutant dilution for dispersal, should be considered. Technology for pollution abatement is available, but not always economically feasible.

  20. Air Pollution and Stroke.

    Science.gov (United States)

    Lee, Kuan Ken; Miller, Mark R; Shah, Anoop S V

    2018-01-01

    The adverse health effects of air pollution have long been recognised; however, there is less awareness that the majority of the morbidity and mortality caused by air pollution is due to its effects on the cardiovascular system. Evidence from epidemiological studies have demonstrated a strong association between air pollution and cardiovascular diseases including stroke. Although the relative risk is small at an individual level, the ubiquitous nature of exposure to air pollution means that the absolute risk at a population level is on a par with "traditional" risk factors for cardiovascular disease. Of particular concern are findings that the strength of this association is stronger in low and middle income countries where air pollution is projected to rise as a result of rapid industrialisation. The underlying biological mechanisms through which air pollutants exert their effect on the vasculature are still an area of intense discussion. A greater understanding of the effect size and mechanisms is necessary to develop effective strategies at individual and policy levels to mitigate the adverse cardiovascular effects of air pollution.

  1. Indoor air pollution

    International Nuclear Information System (INIS)

    Anwar, J.; Hussain, F.

    2005-01-01

    Indoor air pollution after being a neglected subject for a number of years, is attracting attention recently because it is a side effect of energy crisis. About 50% of world's 6 billion population, mostly in developing countries, depend on biomass and coal in the form of wood, dung and crop residues for domestic energy because of poverty. These materials are burnt in simple stoves with incomplete combustion and infants, children and women are exposed to high levels of indoor air pollution for a considerable period, approximately between 2-4 hours daily. Current worldwide trade in wood fuel is over US $7 billion and about 2 million people are employed full time in production and marketing it. One of the most annoying and common indoor pollutant in both, developing and developed countries, is cigarette smoke. Children in gas-equipped homes had higher incidences of respiratory disease. Babies' DNA can be damaged even before they are born if their mothers breathe polluted air. Exposure to indoor air pollution may be responsible for nearly 2 million excess deaths in developing countries and for 4% of the global burden of the disease. Only a few indoor pollutants have been studied in detail. Indoor air pollution is a major health threat on which further research is needed to define the extent of the problem more precisely and to determine solutions by the policy-makers instead of neglecting it because sufferers mostly belong to Third World countries. (author)

  2. Manganese nanoparticle activates mitochondrial dependent apoptotic signaling and autophagy in dopaminergic neuronal cells

    International Nuclear Information System (INIS)

    Afeseh Ngwa, Hilary; Kanthasamy, Arthi; Gu, Yan; Fang, Ning; Anantharam, Vellareddy; Kanthasamy, Anumantha G.

    2011-01-01

    The production of man-made nanoparticles for various modern applications has increased exponentially in recent years, but the potential health effects of most nanoparticles are not well characterized. Unfortunately, in vitro nanoparticle toxicity studies are extremely limited by yet unresolved problems relating to dosimetry. In the present study, we systematically characterized manganese (Mn) nanoparticle sizes and examined the nanoparticle-induced oxidative signaling in dopaminergic neuronal cells. Differential interference contrast (DIC) microscopy and transmission electron microscopy (TEM) studies revealed that Mn nanoparticles range in size from single nanoparticles (∼ 25 nM) to larger agglomerates when in treatment media. Manganese nanoparticles were effectively internalized in N27 dopaminergic neuronal cells, and they induced a time-dependent upregulation of the transporter protein transferrin. Exposure to 25–400 μg/mL Mn nanoparticles induced cell death in a time- and dose-dependent manner. Mn nanoparticles also significantly increased ROS, accompanied by a caspase-mediated proteolytic cleavage of proapoptotic protein kinase Cδ (PKCδ), as well as activation loop phosphorylation. Blocking Mn nanoparticle-induced ROS failed to protect against the neurotoxic effects, suggesting the involvement of other pathways. Further mechanistic studies revealed changes in Beclin 1 and LC3, indicating that Mn nanoparticles induce autophagy. Primary mesencephalic neuron exposure to Mn nanoparticles induced loss of TH positive dopaminergic neurons and neuronal processes. Collectively, our results suggest that Mn nanoparticles effectively enter dopaminergic neuronal cells and exert neurotoxic effects by activating an apoptotic signaling pathway and autophagy, emphasizing the need for assessing possible health risks associated with an increased use of Mn nanoparticles in modern applications. -- Highlights: ► Mn nanoparticles activate mitochondrial cell death signaling

  3. Grant Programs for Pollution Prevention

    Science.gov (United States)

    The Office of Pollution Prevention and Toxics is responsible for overseeing several grant programs for tribes and states which promote pollution prevention through source reduction and resource conservation.

  4. Two-photon quantum interference in a Michelson interferometer

    International Nuclear Information System (INIS)

    Odate, Satoru; Wang Haibo; Kobayashi, Takayoshi

    2005-01-01

    We have observed two-photon quantum interference in a Michelson interferometer. For the first time, we experimentally demonstrated two-photon quantum interference patterns, which show the transition from nonsubwavelength interference fringes to the general subwavelength interference. At the same time, a photon bunching effect was also shown by a postselection. The |1, 1> state with a single photon in a mode corresponding to each arm of the interferometer was exclusively postselected by using path difference between two arms

  5. Green Synthesis of Iron Nanoparticles and Their Environmental Applications and Implications

    Directory of Open Access Journals (Sweden)

    Sadia Saif

    2016-11-01

    Full Text Available Recent advances in nanoscience and nanotechnology have also led to the development of novel nanomaterials, which ultimately increase potential health and environmental hazards. Interest in developing environmentally benign procedures for the synthesis of metallic nanoparticles has been increased. The purpose is to minimize the negative impacts of synthetic procedures, their accompanying chemicals and derivative compounds. The exploitation of different biomaterials for the synthesis of nanoparticles is considered a valuable approach in green nanotechnology. Biological resources such as bacteria, algae fungi and plants have been used for the production of low-cost, energy-efficient, and nontoxic environmental friendly metallic nanoparticles. This review provides an overview of various reports of green synthesised zero valent metallic iron (ZVMI and iron oxide (Fe2O3/Fe3O4 nanoparticles (NPs and highlights their substantial applications in environmental pollution control. This review also summarizes the ecotoxicological impacts of green synthesised iron nanoparticles opposed to non-green synthesised iron nanoparticles.

  6. Green Synthesis of Iron Nanoparticles and Their Environmental Applications and Implications

    Science.gov (United States)

    Saif, Sadia; Tahir, Arifa; Chen, Yongsheng

    2016-01-01

    Recent advances in nanoscience and nanotechnology have also led to the development of novel nanomaterials, which ultimately increase potential health and environmental hazards. Interest in developing environmentally benign procedures for the synthesis of metallic nanoparticles has been increased. The purpose is to minimize the negative impacts of synthetic procedures, their accompanying chemicals and derivative compounds. The exploitation of different biomaterials for the synthesis of nanoparticles is considered a valuable approach in green nanotechnology. Biological resources such as bacteria, algae fungi and plants have been used for the production of low-cost, energy-efficient, and nontoxic environmental friendly metallic nanoparticles. This review provides an overview of various reports of green synthesised zero valent metallic iron (ZVMI) and iron oxide (Fe2O3/Fe3O4) nanoparticles (NPs) and highlights their substantial applications in environmental pollution control. This review also summarizes the ecotoxicological impacts of green synthesised iron nanoparticles opposed to non-green synthesised iron nanoparticles. PMID:28335338

  7. The role of nanoparticles in the changing of physical and chemical properties of oil

    International Nuclear Information System (INIS)

    Xalilov, R.; Nasibova, A.; Lesin, V.; Xomutov, G.

    2015-01-01

    Researches in recent years have been shown that, magnetic nanoparticles of iron oxides are widespread in animate and inanimate nature. Researches carried out in the natural systems (plant, oil and etc.) by the electron paramagnetic resonance (EPR) method show that the bio generation of the nanoparticles has been highlighted. Comprehensive analysis of the influence of radioactive pollution to the plants has been conducted during the initial studies of natural systems for cliffing the mechanisms of the biogenic generation of magnetic nanoparticles, wide EPR signal characterizing the magnetic nanoparticles was observed. Magnetic nanoparticles can be included into the structure of fractal aggregates of colloid components of oil. Influence of the magnetic field to the main physical chemical properties of oil was happened as a result of bio mineralization process with the presence of generated magnetic nanoparticles.

  8. Core/shell structured ZnO/SiO2 nanoparticles: Preparation, characterization and photocatalytic property

    International Nuclear Information System (INIS)

    Zhai Jing; Tao Xia; Pu Yuan; Zeng Xiaofei; Chen Jianfeng

    2010-01-01

    ZnO nanoparticles were prepared by a simple chemical synthesis route. Subsequently, SiO 2 layers were successfully coated onto the surface of ZnO nanoparticles to modify the photocatalytic activity in acidic or alkaline solutions. The obtained particles were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS) and zeta potential. It was found that ultrafine core/shell structured ZnO/SiO 2 nanoparticles were successfully obtained. The photocatalytic performance of ZnO/SiO 2 core/shell structured nanoparticles in Rhodamine B aqueous solution at varied pH value were also investigated. Compared with uncoated ZnO nanoparticles, core/shell structured ZnO/SiO 2 nanoparticles with thinner SiO 2 shell possess improved stability and relatively better photocatalytic activity in acidic or alkaline solutions, which would broaden its potential application in pollutant treatment.

  9. Quantum interference experiments with complex organic molecules

    International Nuclear Information System (INIS)

    Eibenberger, S. I.

    2015-01-01

    Matter-wave interference with complex particles is a thriving field in experimental quantum physics. The quest for testing the quantum superposition principle with highly complex molecules has motivated the development of the Kapitza-Dirac-Talbot-Lau interferometer (KDTLI). This interferometer has enabled quantum interference with large organic molecules in an unprecedented mass regime. In this doctoral thesis I describe quantum superposition experiments which we were able to successfully realize with molecules of masses beyond 10 000 amu and consisting of more than 800 atoms. The typical de Broglie wavelengths of all particles in this thesis are in the order of 0.3-5 pm. This is significantly smaller than any molecular extension (nanometers) or the delocalization length in our interferometer (hundreds of nanometers). Many vibrational and rotational states are populated since the molecules are thermally highly excited (300-1000 K). And yet, high-contrast quantum interference patterns could be observed. The visibility and position of these matter-wave interference patterns is highly sensitive to external perturbations. This sensitivity has opened the path to extensive studies of the influence of internal molecular properties on the coherence of their associated matter waves. In addition, it enables a new approach to quantum-assisted metrology. Quantum interference imprints a high-contrast nano-structured density pattern onto the molecular beam which allows us to resolve tiny shifts and dephasing of the molecular beam. I describe how KDTL interferometry can be used to investigate a number of different molecular properties. We have studied vibrationally-induced conformational changes of floppy molecules and permanent electric dipole moments using matter-wave deflectometry in an external electric field. We have developed a new method for optical absorption spectroscopy which uses the recoil of the molecules upon absorption of individual photons. This allows us to

  10. On spectral pollution

    International Nuclear Information System (INIS)

    Llobet, X.; Appert, K.; Bondeson, A.; Vaclavik, J.

    1990-01-01

    Finite difference and finite element approximations of eigenvalue problems, under certain circumstances exhibit spectral pollution, i.e. the appearance of eigenvalues that do not converge to the correct value when the mesh density is increased. In the present paper this phenomenon is investigated in a homogeneous case by means of discrete dispersion relations: the polluting modes belong to a branch of the dispersion relation that is strongly distorted by the discretization method employed, or to a new, spurious branch. The analysis is applied to finite difference methods and to finite element methods, and some indications about how to avoiding polluting schemes are given. (author) 5 figs., 10 refs

  11. Environmental pollution studies

    CERN Document Server

    Best, Gerry

    1999-01-01

    This book examines a number of important contemporary environmental issues in an informative and easy-to-read style. The topics covered include sewage treatment, eutrophication, air pollution, acid rain, global warming and pollution from farming. A particularly valuable section of the book describes a range of tests that can be carried out on various environmental parameters. The procedures require relatively simple equipment and they have been pre-tested in a school laboratory. "Environmental Pollution Studies" will be of value to senior school pupils and students at college or university embarking on courses in environmental science.

  12. Earthworms and Soil Pollutants

    Directory of Open Access Journals (Sweden)

    Kazuyoshi Tamae

    2011-11-01

    Full Text Available Although the toxicity of metal contaminated soils has been assessed with various bioassays, more information is needed about the biochemical responses, which may help to elucidate the mechanisms involved in metal toxicity. We previously reported that the earthworm, Eisenia fetida, accumulates cadmium in its seminal vesicles. The bio-accumulative ability of earthworms is well known, and thus the earthworm could be a useful living organism for the bio-monitoring of soil pollution. In this short review, we describe recent studies concerning the relationship between earthworms and soil pollutants, and discuss the possibility of using the earthworm as a bio-monitoring organism for soil pollution.

  13. Dangers of environmental pollution

    International Nuclear Information System (INIS)

    Schaer, M.

    1978-01-01

    Environmental pollution is ever increasing. Protection of the environment must not be neglected for economic reasons. Damage to health due to environmental effects is hard to determine epidemiologically as there are nearly always several causes to consider at the same time. Still, the increase in environmental pollution results in increased damage to humans, animals, and plants. The many dangers to health can be illustrated by the example of energy demand and the different ways to meet it. It is highly necessary to create environmental laws which aim at a reduction of environmental pollution. (orig.) [de

  14. Measuring pollution prevention

    International Nuclear Information System (INIS)

    Stephan, D.G.; Bridges, J.S.

    1992-01-01

    To assess progress in pollution prevention, estimates or measurements of the amounts of pollution actually prevented have to be made. Such estimates or measurements tell us how far we have come and, possibly, how much farther there is to go in utilizing pollution prevention as a tool for improving environmental quality. They can, theoretically, be used to assess progress on a scale ranging from the individual facility or even the individual process or activity generation wastes to scale as large as a geographical area such as a county, a state or even the United States as a whole. 3 refs

  15. Nonlinear and quantum optics near nanoparticles

    Science.gov (United States)

    Dhayal, Suman

    We study the behavior of electric fields in and around dielectric and metal nanoparticles, and prepare the ground for their applications to a variety of systems viz. photovoltaics, imaging and detection techniques, and molecular spectroscopy. We exploit the property of nanoparticles being able to focus the radiation field into small regions and study some of the interesting nonlinear, and quantum coherence and interference phenomena near them. The traditional approach to study the nonlinear light-matter interactions involves the use of the slowly varying amplitude approximation (SVAA) as it simplifies the theoretical analysis. However, SVVA cannot be used for systems which are of the order of the wavelength of the light. We use the exact solutions of the Maxwell's equations to obtain the fields created due to metal and dielectric nanoparticles, and study nonlinear and quantum optical phenomena near these nanoparticles. We begin with the theoretical description of the electromagnetic fields created due to the nonlinear wavemixing process, namely, second-order nonlinearity in an nonlinear sphere. The phase-matching condition has been revisited in such particles and we found that it is not satisfied in the sphere. We have suggested a way to obtain optimal conditions for any type and size of material medium. We have also studied the modifications of the electromagnetic fields in a collection of nanoparticles due to strong near field nonlinear interactions using the generalized Mie theory for the case of many particles applicable in photovoltaics (PV). We also consider quantum coherence phenomena such as modification of dark states, stimulated Raman adiabatic passage (STIRAP), optical pumping in 4-level atoms near nanoparticles by using rotating wave approximation to describe the Hamiltonian of the atomic system. We also considered the behavior of atomic and the averaged atomic polarization in 7-level atoms near nanoparticles. This could be used as a prototype to study

  16. Interference of an array of independent Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Hadzibabic, Zoran; Stock, Sabine; Battelier, Baptiste; Bretin, Vincent; Dalibard, Jean

    2004-01-01

    We have observed high-contrast matter wave interference between 30 Bose-Einstein condensates with uncorrelated phases. Interferences were observed after the independent condensates were released from a one-dimensional optical lattice and allowed to overlap. This phenomenon is explained with a simple theoretical model, which generalizes the analysis of the interference of two condensates

  17. Interference contrast in multi-source few photon optics

    OpenAIRE

    Laskowski, Wieslaw; Wiesniak, Marcin; Zukowski, Marek; Bourennane, Mohamed; Weinfurter, Harald

    2009-01-01

    Many recent experiments employ several parametric down conversion (PDC) sources to get multiphoton interference. Such interference has applications in quantum information. We study here how effects due to photon statistics, misalignment, and partial distinguishability of the PDC pairs originating from different sources may lower the interference contrast in the multiphoton experiments.

  18. Visualizing the Solute Vaporization Interference in Flame Atomic Absorption Spectroscopy

    Science.gov (United States)

    Dockery, Christopher R.; Blew, Michael J.; Goode, Scott R.

    2008-01-01

    Every day, tens of thousands of chemists use analytical atomic spectroscopy in their work, often without knowledge of possible interferences. We present a unique approach to study these interferences by using modern response surface methods to visualize an interference in which aluminum depresses the calcium atomic absorption signal. Calcium…

  19. Therapeutic Potential of Biologically Reduced Silver Nanoparticles from Actinomycete Cultures

    International Nuclear Information System (INIS)

    Sukanya, M.K.; Saju, K.A.; Praseetha, P.K.; Sakthivel, G.

    2013-01-01

    Silver nanoparticles are applied in nanomedicine from time immemorial and are still used as powerful antibiotic and anti-inflammatory agents. Antibiotics produced by actinomycetes are popular in almost all the therapeutic measures, and this study has proven that these microbes are also helpful in the biosynthesis of silver nanoparticles with good surface and size characteristics. Silver can be synthesized by various chemical methodologies, and most of them have turned to be toxic. This study has been successful in isolating the microbes from polluted environment, and subjecting them to the reduction of silver nanoparticles, characterizing the nanoparticles by UV spectrophotometry and transmission electron microscopy. The nanoparticles produced were tested for their antimicrobial property, and the zone of inhibition was greater than those produced by their chemically synthesized counterparts. Actinomycetes, helpful in bioremediating heavy metals, are useful for the production of metallic nanoparticles. The biosynthesized silver nanoparticles loaded with antibiotics prove to be better in killing the pathogens and have opened up new areas for developing nanobiotechnological research based on microbial applications.

  20. Air pollution and respiratory illness

    Energy Technology Data Exchange (ETDEWEB)

    Indra, G. [DIET, Uttamasolapuram, Salem (India)

    2005-07-01

    This presentation provides an overview of air pollution and impacts on public health. It provides a definition of pollution according to the Oxford English dictionary and categorizes the different types of pollution according to air, water, land and noise. It discusses air pollution and its pollutants (gaseous and particulate pollutants) as well as the diameter of the pollutant (dust, smoke, and gas). The paper also illustrates the formation of acid rain and discusses the amount of pollutants in the atmosphere per year. It presents occupational diseases, discusses radio active pollutants, respiratory illnesses as well as pollution prevention and control. The paper concluded that more research is needed to obtain information on ways to reduce the quantity of pollutants being discharged from special processes. 3 refs., 2 figs., 2 tabs.

  1. Organotin pollution from pleasure craft at Paraty, a tourist area of Southeastern Brazil: amelioration or interference?

    Directory of Open Access Journals (Sweden)

    Camila de Leon Lousada Borges

    2013-09-01

    Full Text Available Some organotin compounds, such as TBT, are endocrine disruptors and harm marine ecosystems. Even after the global ban on organotins, increasing imposex levels have been detected in Stramonita haemastoma analyzed in 2004 and 2011 in some locations at Paraty, a tourist area in southeastern Brazil. The results of this study indicate that particulate and dissolved organic carbon and xenoestrogens might be interfering in this syndrome's development, leading to underestimation of imposex evaluation. Chemical analysis of three mangrove swamp sediments in the area showed the presence of TBT (16.0 - 205.7 ng Sn g-1, DBT (10.1 - 16.4 ng Sn g-1 and MBT (10.1 - 10.2 ng Sn g-1 even at the reference sites. The concentrations of butyltins and the increased incidence of imposexat some stations indicate recent inputs of TBT in the study area due to its illegal use on small vessels.

  2. Polycyclic aromatic hydrocarbon-polluted dredged peat sediments and earthworms: a mutual interference

    NARCIS (Netherlands)

    Eijsackers, H.J.P.; Jonge, de S.; Muijs, B.; Slijkerman, D.; Gestel, van C.A.M.

    2001-01-01

    In lowland areas of the Netherlands, any peat sediments will gradually become enriched with anthropogenically derived Polycyclic Aromatic Hydrocarbons. Due to Dutch policy standards these (anaerobic) sediments are not allowed to be dredged and placed onto land. Under aerobic conditions, however,

  3. Landsat and water pollution

    Science.gov (United States)

    Castruccio, P.; Fowler, T.; Loats, H., Jr.

    1979-01-01

    Report presents data derived from satellite images predicting pollution loads after rainfall. It explains method for converting Landsat images of Eastern United States into cover maps for Baltimore/five county region.

  4. Lichens and atmospheric pollution

    Energy Technology Data Exchange (ETDEWEB)

    Tallis, J H

    1964-09-01

    The extreme sensitivity of lichens, particularly the larger ones, to industrialization has been recognized for many years. Most people attribute the absence of lichens from urban areas to the atmospheric pollution prevailing, and a few attribute it to climatic dryness, resulting from efficient drainage systems in towns. The two main components of air pollution are solid matter, or soot, and gaseous sulfur dioxide. The main effects of pollution appear to be: a direct reduction of light intensity by smoke haze, a deposit of soot on the plant surface, an acidification of the soil, and direct damage to plants. A body of evidence indicates that SO/sub 2/ may be the main harmful component for lichens. The distribution of lichens thus might be used to determine the limits within which atmospheric pollution is operating. 5 references.

  5. Students 'Weigh' Atmospheric Pollution.

    Science.gov (United States)

    Caporaloni, Marina

    1998-01-01

    Describes a procedure developed by students that measures the mass concentration of particles in a polluted urban atmosphere. Uses a portable fan and filters of various materials. Compares students' data with official data. (DDR)

  6. Sources of pollution

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Sources of pollution. Domestic wastewater (Sewage). Organic matter; Nitrogen & phosphorus; Pathogens, viruses, …. Agricultural runoff. Nitrogen & phosphorus; Pesticides; Industrial effluents; Organics (oil &grease, pigments, phenols, organic matter ….) Heavy ...

  7. Indoor air pollution

    International Nuclear Information System (INIS)

    Spengler, J.D.

    1985-01-01

    Although official efforts to control air pollution have traditionally focused on outdoor air, it is now apparent that elevated contaminant concentrations are common inside some private and public buildings. Concerns about potential public health problems due to indoor air pollution are based on evidence that urban residents typically spend more than 90 percent of their time indoors, concentrations of some contaminants are higher indoors than outdoors, and for some pollutants personal exposures are not characterized adequately by outdoor measurements. Among the more important indoor contaminants associated with health or irritation effects are passive tobacco smoke, radon decay products, carbon monoxide, nitrogen dioxide, formaldehyde, asbestos fibers, microorganisms and aeroallergens. Efforts to assess health risks associated with indoor air pollution are limited by insufficient information about the number of people exposed, the pattern and severity of exposures, and the health consequences of exposures. An overall strategy should be developed to investigate indoor exposures, health effects, control options, and public policy alternatives

  8. Fate of pollutants

    International Nuclear Information System (INIS)

    Chapta, S.C.; Boyer, J.M.

    1990-01-01

    A literature review is presented of the fate of pollutants in sediment and water systems. Topics of discussion include the following: modeling, observations, and general studies; chlorinated xenobiotic chemicals; nonchlorinated xenobiotic chemicals; pesticides; heavy metals; and radionuclides

  9. Pollution of coastal seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    Pollution of various environments is a consequence of population growth and industrialisation. Coastal seas form part of marine environment and are very rich in minerals, crude oil fishes etc. They are also being used for disposal of wastes from...

  10. Scientific stream pollution analysis

    National Research Council Canada - National Science Library

    Nemerow, Nelson Leonard

    1974-01-01

    A comprehensive description of the analysis of water pollution that presents a careful balance of the biological,hydrological, chemical and mathematical concepts involved in the evaluation of stream...

  11. Sum Frequency Generation Studies of Hydrogenation Reactions on Platinum Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Krier, James M. [Univ. of California, Berkeley, CA (United States)

    2013-08-31

    Sum Frequency Generation (SFG) vibrational spectroscopy is used to characterize intermediate species of hydrogenation reactions on the surface of platinum nanoparticle catalysts. In contrast to other spectroscopy techniques which operate in ultra-high vacuum or probe surface species after reaction, SFG collects information under normal conditions as the reaction is taking place. Several systems have been studied previously using SFG on single crystals, notably alkene hydrogenation on Pt(111). In this thesis, many aspects of SFG experiments on colloidal nanoparticles are explored for the first time. To address spectral interference by the capping agent (PVP), three procedures are proposed: UV cleaning, H2 induced disordering and calcination (core-shell nanoparticles). UV cleaning and calcination physically destroy organic capping while disordering reduces SFG signal through a reversible structural change by PVP.

  12. Template assisted synthesis and optical properties of gold nanoparticles.

    Science.gov (United States)

    Fodor, Petru; Lasalvia, Vincenzo

    2009-03-01

    A hybrid nanofabrication method (interference lithography + self assembly) was explored for the fabrication of arrays of gold nanoparticles. To ensure the uniformity of the nanoparticles, a template assisted synthesis was used in which the gold is electrodeposited in the pores of anodized aluminum membranes. The spacing between the pores and their ordering is controlled in the first fabrication step of the template in which laser lithography and metal deposition are used to produce aluminum films with controlled strain profiles. The diameter of the pores produced after anodizing the aluminum film in acidic solution determines the diameter of the gold particles, while their aspect ratio is controlled through the deposition time. Optical absorbance spectroscopy is used to evaluate the ability to tune the nanoparticles plasmon resonance spectra through control over their size and aspect ratio.

  13. Air pollution and bronchitis

    Energy Technology Data Exchange (ETDEWEB)

    Pemberton, J; Goldberg, C

    1954-01-01

    Bronchitis mortality in males and females 45 to 65 or over 65 years of age was compared with air pollution in the county boroughs of England and Wales in 1950 to 1952. There was significant association between SO/sub 2/ and bronchitis mortality for men but only occasionally significant for women. Association between particulate matter and bronchitis was less consistent. Socio-economic class had no association with pollutant levels suggesting this factor does not affect bronchitis mortality significantly.

  14. Radioisotope dust pollution monitor

    International Nuclear Information System (INIS)

    Szepke, R.; Harasimczuk, J.; Dobrowiecki, J.

    1990-01-01

    Measuring principles and specification of two dust monitors: station-type AMIZ and portable-type PIK-10 for ambient air pollution are presented. The first one, a fully automatic instrument is destined for permanent monitoring of air pollution in preset sampling time from .25 to 24 hours. The second one was developed as a portable working model. Both instruments display their results in digital form in dust concentration units. (author)

  15. Indoor Air Pollution

    OpenAIRE

    Kirk R. Smith

    2003-01-01

    Outdoor air pollution in developing-country cities is difficult to overlook. Indoor air pollution caused by burning such traditional fuels as wood, crop residues, and dung is less evident, yet it is responsible for a significant part of country and global disease burdens. The main groups affected are poor women and children in rural areas and urban slums as they go about their daily activi...

  16. INDOOR AIR POLLUTION

    OpenAIRE

    Ahmet Soysal; Yucel Demiral

    2007-01-01

    The existance of hazardious materials including biological, chemical, and physical agents such as carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxides, radon, volotile organic compounds, microorganisms in houses and the other non-industrilized buildings have been defined as “indoor air pollution”. Indoor air pollutants could possible arised from inside or outside environment and categorized into six subgroups. Almost 80% Turkish population have living in the urban areas...

  17. Radioactive marine pollution

    International Nuclear Information System (INIS)

    Pontavice, E. du

    1976-01-01

    Certain provision in international law aim to prevent radioactive marine pollution and others concern compensation of damage from nuclear pollution. Prevention requires regulation of the disposal of wastes from nuclear industry from the operation of nuclear powered ships and from transport of fissile materials. As regards damage, if the measures to limit the extent of the damage come under the law of the sea, the priority of nuclear law over maritime law is clear in respect of financial compensation. (Auth) [fr

  18. Environmental pollution and allergies

    OpenAIRE

    Takano, H; Inoue, K

    2017-01-01

    Environmental changes are thought to be the main factor in the rapid increase and worsening of allergic diseases. While there have been significant changes in many environmental factors, including in environments such as residential, health and sanitation, food, and water/soil/atmospheric environments, the root of each of these changes is likely an increase in chemical substances. In fact, various environmental pollutants, such as air pollutants and chemical substances, have been shown to wor...

  19. Industrial pollution prevention handbook

    International Nuclear Information System (INIS)

    Freeman, H.M.

    1995-01-01

    This book presents the techniques, technologies, regulations, and strategies that define pollution prevention. The subject is addressed from many perspectives by prominent experts. In many ways pollution prevention, rather than being a specialty field itself, is actually a convergence of fields drawing upon knowledge in a wide variety of more typical fields of expertise. Individual chapters have been processed separately for inclusion in the appropriate data bases

  20. Sol-gel synthesis of 8 nm magnetite (Fe 3O 4) nanoparticles and their magnetic properties

    KAUST Repository

    Lemine, O. M.

    2012-10-01

    Magnetite (Fe 3O 4) nanoparticles were successfully synthesized by a sol-gel method. The obtained nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive analysis by X-ray (EDAX), transmission electron microscopy (TEM), superconducting quantum interference device (SQUID) and Mössbauer spectrometry. XRD and Mössbauer measurements indicate that the obtained nanoparticles are single phase. TEM analysis shows the presence of spherical nanoparticles with homogeneous size distribution of about 8 nm. Room temperature ferromagnetics behavior was confirmed by SQUID measurements. The mechanism of nanoparticles formation and the comparison with recent results are discussed. Finally, the synthesized nanoparticles present a potential candidate for hyperthermia application given their saturation magnetization. © 2012 Elsevier Ltd. All rights reserved.

  1. Sol-gel synthesis of 8 nm magnetite (Fe 3O 4) nanoparticles and their magnetic properties

    KAUST Repository

    Lemine, O. M.; Omri, Karim; Zhang, Bei; El Mir, Lassaad; Sajieddine, Mohammed; Alyamani, Ahmed Y.; Bououdina, M.

    2012-01-01

    Magnetite (Fe 3O 4) nanoparticles were successfully synthesized by a sol-gel method. The obtained nanoparticles were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive analysis by X-ray (EDAX), transmission electron microscopy (TEM), superconducting quantum interference device (SQUID) and Mössbauer spectrometry. XRD and Mössbauer measurements indicate that the obtained nanoparticles are single phase. TEM analysis shows the presence of spherical nanoparticles with homogeneous size distribution of about 8 nm. Room temperature ferromagnetics behavior was confirmed by SQUID measurements. The mechanism of nanoparticles formation and the comparison with recent results are discussed. Finally, the synthesized nanoparticles present a potential candidate for hyperthermia application given their saturation magnetization. © 2012 Elsevier Ltd. All rights reserved.

  2. Sensing sulfur oxides and other sulfur bearing pollutants with solid electrolyte pellets. I. Gas concentration cells

    Energy Technology Data Exchange (ETDEWEB)

    Chamberland, A M; Gauthier, J M

    1977-01-01

    A new sensing technique using a solid electrolyte has been demonstrated for sulfur-bearing pollutants. Based on potentiometric measurements across a pellet of potassium sulfate, this sensor allows concentrations of sulfur dioxides, sulfur trioxide, hydrogen sulfide, methyl mercaptan and carbonyl sulfide in air to be measured with accuracy. Its operational concentration range at the present time is 0.1 ppM up to at least 10,000 ppM. The presence of other common pollutants such as carbon dioxide, methane, nitric oxide and nitrogen dioxide does not interfere with the measurement of air samples containing sulfur-bearing pollutants.

  3. Effect of hydrophobic coating on the magnetic anisotropy and radiofrequency heating of γ-Fe2O3 nanoparticles

    International Nuclear Information System (INIS)

    Singh, Mandeep; Ulbrich, Pavel; Prokopec, Vadym; Svoboda, Pavel; Šantavá, Eva; Štěpánek, František

    2013-01-01

    The effect of a hydrophobic (oleic acid) coating on the magnetic properties of maghemite (γ-Fe 2 O 3 ) nanoparticles was investigated. The nanoparticles were prepared by a novel bi-phasic co-precipitation route and their properties compared with uncoated nanoparticles and nanoparticles prepared by a standard single-phase process. The oleic acid coated nanoparticles had a mean diameter of 6 nm when the two-phase precipitation procedure was used compared to 12 nm for nanoparticles prepared in a single phase under otherwise identical conditions. Super Quantum Interference Device measurements show superparamagnetism of the nanoparticles, with a saturation magnetization at 4 K to be 66.4 emu/g and 89.0 emu/g for the coated nanoparticles obtained by two- and single-phase procedure, respectively. Zero-field-cooled and field-cooled curves reveal a dramatic shift in the blocking temperature of the coated nanoparticles, and a significant change in their anisotropy. The hydrophobic nanoparticles were able to form stable ferrofluids in a range of organic solvents and show good heating rates in a 400 kHz alternating magnetic field. - Highlights: ► Hydrophobic iron oxide nanoparticles synthesized by a new microemulsion approach. ► Strong influence of oleic acid coating on blocking temperature observed. ► Stable non-aqueous ferrofluids prepared. ► Favorable heating rates under alternating magnetic field

  4. De-alloyed platinum nanoparticles

    Science.gov (United States)

    Strasser, Peter [Houston, TX; Koh, Shirlaine [Houston, TX; Mani, Prasanna [Houston, TX; Ratndeep, Srivastava [Houston, TX

    2011-08-09

    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

  5. Interference from retrieval cues in Parkinson's disease.

    Science.gov (United States)

    Crescentini, Cristiano; Marin, Dario; Del Missier, Fabio; Biasutti, Emanuele; Shallice, Tim

    2011-11-01

    Existing studies on memory interference in Parkinson's disease (PD) patients have provided mixed results and it is unknown whether PD patients have problems in overcoming interference from retrieval cues. We investigated this issue by using a part-list cuing paradigm. In this paradigm, after the study of a list of items, the presentation of some of these items as retrieval cues hinders the recall of the remaining ones. We tested PD patients' (n = 19) and control participants' (n = 16) episodic memory in the presence and absence of part-list cues, using initial-letter probes, and following either weak or strong serial associative encoding of list items. Both PD patients and control participants showed a comparable and significant part-list cuing effect after weak associative encoding (13% vs. 12% decrease in retrieval in part-list cuing vs. no part-list cuing -control- conditions in PD patients and control participants, respectively), denoting a similar effect of cue-driven interference in the two populations when a serial retrieval strategy is hard to develop. However, only PD patients showed a significant part-list cuing effect after strong associative encoding (20% vs. 5% decrease in retrieval in patients and controls, respectively). When encoding promotes the development of an effective serial retrieval strategy, the presentation of part-list cues has a specifically disruptive effect in PD patients. This indicates problems in strategic retrieval, probably related to PD patients' increased tendency to rely on external cues. Findings in control conditions suggest that less effective encoding may have contributed to PD patients' memory performance.

  6. Pollution Microbiology, A Laboratory Manual.

    Science.gov (United States)

    Finstein, Melvin S.

    This manual is designed for use in the laboratory phase of courses dealing with microbial aspects of pollution. It attempts to cover the subject area broadly in four major categories: (1) microorganisms in clean and polluted waters, (2) carbonaceous pollutants, (3) nitrogen, phosphorus, iron, and sulfur as pollutants, and (4) sanitary…

  7. Phase-Modulation Laser Interference Microscopy

    DEFF Research Database (Denmark)

    Brazhe, Alexey; Brazhe, Nadezda; Maximov, G. V.

    2008-01-01

    We describe how phase-modulation laser interference microscopy and wavelet analysis can be applied to noninvasive nonstained visualization and study of the structural and dynamical properties of living cells. We show how phase images of erythrocytes can reveal the difference between various...... erythrocyte forms and stages of hemolysis and how phase images of neurons reveal their complex intracellular structure. Temporal variations of the refractive index are analyzed to detect cellular rhythmic activity on different time scales as well as to uncover interactions between the cellular processes....

  8. On interference of cumulative proton production mechanisms

    International Nuclear Information System (INIS)

    Braun, M.A.; Vechernin, V.V.

    1993-01-01

    The dynamical picture of the cumulative proton production in hA-collisions by means of diagram analysis with NN interaction described by a non-relativistic NN potential is considered. The contributions of the various mechanisms (spectator, direct and rescattering) for backward hemisphere proton production within the framework of this common approach is calculated. The emphasis is on the comparison of the relative contributions of these mechanisms for various angles, taking into account the interference of these contributions. Comparison with experimental data is also presented. (author)

  9. Interference effects in negative ion formation

    International Nuclear Information System (INIS)

    Alvarez, I.; Morales, A.; de Urquijo, J.; Cisneros, C.

    1984-01-01

    This paper presents recent data on differential cross sections for H - formation from collisions of H + and H 0 with Ar in the energy range 1.0 to 4 keV. Experimental data exhibit a sharp maximum at 0 0 scattering angle as well as an oscillatory structure. The functional form and scaling properties strongly indicate that there is a glory maximum which occurs when the classical deflection function changes over from attractive to repulsive at some finite impact parameter. The oscillations are predicted by the Bessel function and may be said to arise from interference of the contributions from the two branches of the deflection function near to a glory

  10. Interference Coordination for 5G New Radio

    DEFF Research Database (Denmark)

    Alvarez, Beatriz Soret; De Domenico, Antonio; Bazzi, Samer

    2018-01-01

    The arrival of the 5G NR provides a unique opportunity for introducing new inter-cell interference coordination (ICIC) mechanisms. The objective is twofold: to better exploit the benefits of ICIC in coherence with the rest of radio resource management (RRM) principles in 5G, and to support new...... results quantify the performance benefits of the different techniques under heterogeneous key performance indicators (KPIs). We also discuss the standardization effort required for having each of these techniques included in the 5G NR specifications....

  11. Using RNA Interference to Study Protein Function

    OpenAIRE

    Curtis, Carol D.; Nardulli, Ann M.

    2009-01-01

    RNA interference can be extremely useful in determining the function of an endogenously-expressed protein in its normal cellular environment. In this chapter, we describe a method that uses small interfering RNA (siRNA) to knock down mRNA and protein expression in cultured cells so that the effect of a putative regulatory protein on gene expression can be delineated. Methods of assessing the effectiveness of the siRNA procedure using real time quantitative PCR and Western analysis are also in...

  12. Quantum interference effects in nanostructured Au

    CERN Document Server

    Pratumpong, P; Evans, S D; Johnson, S; Howson, M A

    2002-01-01

    We present results on the magnetoresistance and temperature dependence of the resistivity for nanostructured Au produced by chemical means. The magnetoresistance was typical of highly disordered metals exhibiting quantum interference effects. We fitted the data and were able to determine the spin-orbit scattering relaxation time to be 10 sup - sup 1 sup 2 s and we found the inelastic scattering time at 10 K to be 10 sup - sup 1 sup 1 s. The inelastic scattering rate varied as T sup 3 between 4 and 20 K, which is typical for electron-phonon scattering in disordered metals.

  13. Interference of Multiple Surface Plasmon Polaritons

    International Nuclear Information System (INIS)

    Wang, Dapeng; Yuan, Xiaocong; Lin, Jiao

    2017-01-01

    Benefiting from strongly electromagnetic confinement and enhancement effects, surface plasmon polaritons (SPPs) hold great promises for tailoring light on micro and nanoscale. By contrast with previous efforts which massively concentrate on localized SPP mode, we investigated the propagating SPPs in this paper. A number of symmetrical gratings on metal surface are employed to excite multiple SPPs. Interestingly, the exotic interfering phenomena have been observed. They show good agreement with free-space interferences and take advantage of precise controllability. These findings will be promising in the applications of optical tweezers and SPP lithography. (paper)

  14. Preserved cumulative semantic interference despite amnesia

    Directory of Open Access Journals (Sweden)

    Gary Michael Oppenheim

    2015-05-01

    As predicted by Oppenheim et al’s (2010 implicit incremental learning account, WRP’s BCN RTs demonstrated strong (and significant repetition priming and semantic blocking effects (Figure 1. Similar to typical results from neurally intact undergraduates, WRP took longer to name pictures presented in semantically homogeneous blocks than in heterogeneous blocks, an effect that increased with each cycle. This result challenges accounts that ascribe cumulative semantic interference in this task to explicit memory mechanisms, instead suggesting that the effect has the sort of implicit learning bases that are typically spared in hippocampal amnesia.

  15. Phasor Measurement Unit under Interference Conditions

    DEFF Research Database (Denmark)

    Ghiga, Radu; Martin, Kenneth E.; Wu, Qiuwei

    2017-01-01

    interference condition scenarios. In the first scenario, noise is added to the PMU input signal. The test runs a sweep of Signalto-Noise Ratios (SNR) and the accuracy versus the noise level is obtained. The second scenario injects multiple harmonics with the input to test the influence on accuracy. The last...... scenario focuses on instrument transformer saturation which leads to a modified waveform injected in the PMU. This test goes through different levels of Current Transformer (CT) saturation and analyzes the effect of saturation on the accuracy of PMUs. The test results show PMU measurements will be degraded...

  16. Cell-phone interference with pocket dosimeters

    International Nuclear Information System (INIS)

    Djajaputra, David; Nehru, Ramasamy; Bruch, Philip M; Ayyangar, Komanduri M; Raman, Natarajan V; Enke, Charles A

    2005-01-01

    Accurate reporting of personal dose is required by regulation for hospital personnel that work with radioactive material. Pocket dosimeters are commonly used for monitoring this personal dose. We show that operating a cell phone in the vicinity of a pocket dosimeter can introduce large and erroneous readings of the dosimeter. This note reports a systematic study of this electromagnetic interference. We found that simple practical measures are enough to mitigate this problem, such as increasing the distance between the cell phone and the dosimeter or shielding the dosimeter, while maintaining its sensitivity to ionizing radiation, by placing it inside a common anti-static bag. (note)

  17. Cell-phone interference with pocket dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Djajaputra, David; Nehru, Ramasamy; Bruch, Philip M; Ayyangar, Komanduri M; Raman, Natarajan V; Enke, Charles A [Department of Radiation Oncology, University of Nebraska Medical Center, 987521 Nebraska Medical Center, Omaha, NE 68198-7521 (United States)

    2005-05-07

    Accurate reporting of personal dose is required by regulation for hospital personnel that work with radioactive material. Pocket dosimeters are commonly used for monitoring this personal dose. We show that operating a cell phone in the vicinity of a pocket dosimeter can introduce large and erroneous readings of the dosimeter. This note reports a systematic study of this electromagnetic interference. We found that simple practical measures are enough to mitigate this problem, such as increasing the distance between the cell phone and the dosimeter or shielding the dosimeter, while maintaining its sensitivity to ionizing radiation, by placing it inside a common anti-static bag. (note)

  18. Interference Coordination for 5G New Radio

    DEFF Research Database (Denmark)

    Alvarez, Beatriz Soret; De Domenico, Antonio; Bazzi, Samer

    2017-01-01

    The arrival of the 5G NR provides a unique opportunity for introducing new inter-cell interference coordination (ICIC) mechanisms. The objective is twofold: to better exploit the benefits of ICIC in coherence with the rest of radio resource management (RRM) principles in 5G, and to support new se...... results quantify the performance benefits of the different techniques under heterogeneous key performance indicators (KPIs). We also discuss the standardization effort required for having each of these techniques included in the 5G NR specifications....

  19. Medical applications of superconducting quantum interference devices

    International Nuclear Information System (INIS)

    Uehara, Gen

    2011-01-01

    SQUIDs (Superconducting Quantum Interference Devices) are applied to clinical areas and basic medical science fields because of their potential for measuring a minute magnetic signal from the human body. Magnetoencephalography, one of their applications, is used for the functional mapping of the brain cortex before surgery and the localization of focus of epilepsy. Recently, their applications to the early-stage detection of dementia and the localization of brain ischemia are suggested. Another application of SQUIDs is magnetospinography, which detects the conduction block in spinal cord signal propagation. (author)

  20. Measurement of Nitrate Concentration in Aqueous Media Using an Electrochemical Nanosensor Based on Silver Nanoparticles-Nanocellulose/Graphene Oxide

    Directory of Open Access Journals (Sweden)

    Majid Shadfar

    2017-11-01

    Full Text Available Nitrate pollution is at the forefront of groundwater contamination which poses serious environmental and public health hazards.  Nitrate is usually released in solution from agricultural activities and finds its way into groundwater resources. The objective of the present study was to determine, accurately concentrations of nitrate ions in water samples from the environment using sensitive electrochemical methods. For this purpose, a modified glassy carbon electrode modified with a nanocomposite consisting of silver nanoparticles, nanocellulose, and graphene oxide (Ag/NC/GO-GCE was used. The characterization of the nanocomposite was investigated using scanning electron microscope (SEM, X-Ray diffraction (XRD, and electrochemical impedance spectroscopy (EIS. The modified Ag/NC/GO-GCE electrode was used as nanosensor for the electrocatalytic determination of nitrate using the voltammetric method. The effects of the parameters of scan rate, pH, and different nitrate concentrations were studied and the optimum conditions were obtained. A limit of detection of 0.016 µM (S/N=3 was found in the linear range of 0.005 to 10 mM nitrate. The Ag/NC/GO-GCE electrode exhibited a synergistic effect toward voltammetric determination of nitrate in the presence of graphene oxide, nanocellulose, and silver nanocatalyst. The nanosensor developed here showed excellent sensitivity, selectivity, and stability toward nitrate determination in aqueous solutions without any significant interference.

  1. Health Effects of Ozone and Particle Pollution

    Science.gov (United States)

    ... this page: Health Effects of Ozone and Particle Pollution Two types of air pollution dominate in the ... So what are ozone and particle pollution? Ozone Pollution It may be hard to imagine that pollution ...

  2. Human response to interference with TV picture quality

    Energy Technology Data Exchange (ETDEWEB)

    Janischewskyj, W.; Harvey, E.B.

    1980-10-01

    Corona on transmission line conductors and spark gaps on loose or defective transmission line hardware can give rise to visual interference to television interference. The extent to which the interference is a concern (i.e., annoying) depends on the intensity of the interference as well as the strength of the television signal and can best be expressed as a function of the signal-to-noise ratio (SNR), the decibel difference between the wanted signal and the unwanted noise (interference). The study documented in this report has assessed, through subjective testing involving over 500 subjects, the interference level, as a function of SNR, of three different sources of interference: wet-weather conductor corona, a large spark gap (5 mm), and a small spark gap (0.8 mm). The results of the study should be particularly useful to the utility industry in assessing the environmental impact of high-voltage transmission lines.

  3. Interference and protection of electromagnetic pulse to digital signal processor

    International Nuclear Information System (INIS)

    Wang Yan; Jiao Hongling; He Shanhong; Pan Chao; Feng Deren; Che Wenquan; Xiong Ying

    2013-01-01

    The effective electromagnetic pulse protection is studied in this paper, first the interference of electromagnetic pulse simulator path is analyzed, including the digital signal processor (DSP) and the discharge circuit of coupling interference and net electricity coupling interference. Using the structure optimization design, the hardware block reinforcement measurement and the setting of open software trap, and the watchdog anti-jamming measures, the interference test is completed such as the central processor core voltage of DSP, input/output (I/O) ports of DSP and the display screen. The experimental results show that the combination of hardware and software protection reinforcement technology is effective, and the interference pulse amplitude of DSP board I/O port and the kernel work voltage are reduced, and the interference duration is reduced from 2 μs to 400 ns. The interference pulse is effectively restrained. (authors)

  4. Modeling and analysis of laser active interference optical path

    Science.gov (United States)

    Shan, Cong-miao; Sun, Hua-yan; Zhao, Yan-zhong; Chen, Jian-biao; Ren, Jian-ying

    2017-10-01

    By using the geometrical optics and physical optics method, the models of wedge plate interference optical path, Michelson interferometer and Mach Zehnder interferometer thus three different active interference pattern are built. The optical path difference (OPD) launched by different interference patterns, fringe spacing and contrast expression have been derived. The results show that far field interference peak intensity of the wedge plate interference is small, so the detection distance is limited, Michelson interferometer with low contrast affects the performance of detection system, Mach Zehnder interferometer has greater advantages in peak intensity, the variable range of interference fringe spacing and contrast ratio. The results of this study are useful for the theoretical research and practical application of laser active interference detection.

  5. Nanoparticle mediated micromotor motion

    Science.gov (United States)

    Liu, Mei; Liu, Limei; Gao, Wenlong; Su, Miaoda; Ge, Ya; Shi, Lili; Zhang, Hui; Dong, Bin; Li, Christopher Y.

    2015-03-01

    In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ~200 μm s-1. By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ~10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems.In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric

  6. Technology of environmental pollution control

    International Nuclear Information System (INIS)

    Shaheen, E.I.

    1992-01-01

    This book aims to be a comprehensive reference for technological advances in pollution control and abatement and pollution regulations. The first chapter, 'The dilemma of environmental pollution' summarises pollution legislation in the United States and discusses worldwide interest in pollution abatement. Chapter 2 describes some recent environmental disasters and discusses the major air pollutants and their harmful effects. Chapters 3 and 4 assess the various techniques for air pollution control and water pollution control. Chapter 5 is devoted to oil pollution impact and abatement. Solid waste management and methods of solid waste disposal are discussed in chapter 6, and noise pollution, its harmful effects and its control are dealt within chapter 7. Appendices contain a glossary, a summary of the US Clean Air Act and the US drinking water regulations and reference figures and tables relating to energy and the environment. Individual chapters contain many references

  7. Environmental pollution and kidney diseases.

    Science.gov (United States)

    Xu, Xin; Nie, Sheng; Ding, Hanying; Hou, Fan Fan

    2018-05-01

    The burden of disease and death attributable to environmental pollution is becoming a public health challenge worldwide, especially in developing countries. The kidney is vulnerable to environmental pollutants because most environmental toxins are concentrated by the kidney during filtration. Given the high mortality and morbidity of kidney disease, environmental risk factors and their effect on kidney disease need to be identified. In this Review, we highlight epidemiological evidence for the association between kidney disease and environmental pollutants, including air pollution, heavy metal pollution and other environmental risk factors. We discuss the potential biological mechanisms that link exposure to environmental pollutants to kidney damage and emphasize the contribution of environmental pollution to kidney disease. Regulatory efforts should be made to control environmental pollution and limit individual exposure to preventable or avoidable environmental risk. Population studies with accurate quantification of environmental exposure in polluted regions, particularly in developing countries, might aid our understanding of the dose-response relationship between pollutants and kidney diseases.

  8. Limonia acidissima L. leaf mediated synthesis of zinc oxide nanoparticles: A potent tool against Mycobacterium tuberculosis.

    Science.gov (United States)

    Taranath, Tarikere C; Patil, Bheemanagouda N

    2016-06-01

    The present investigation was undertaken to synthesize zinc oxide nanoparticles using Limonia acidissima L. and to test their efficacy against the growth of Mycobacterium tuberculosis. The formation of zinc oxide nanoparticles was confirmed with UV-visible spectrophotometry. Fourier transform infrared spectroscopy shows the presence of bio-molecules involved in the stabilization of zinc oxide nanoparticles. The shape and size was confirmed with atomic force microscope, X-ray diffraction, and high resolution transmission electron microscope. These nanoparticles were tested for their effect on the growth of M. tuberculosis through the microplate alamar blue assay technique. The UV-visible data reveal that an absorbance peak at 374nm confirms formation of zinc oxide nanoparticles and they are spherical in shape with sizes between 12nm and 53nm. These nanoparticles control the growth of M. tuberculosis at 12.5μg/mL. Phytosynthesis of zinc oxide nanoparticles is a green, eco-friendly technology because it is inexpensive and pollution free. In the present investigation, based on our results we conclude that the aqueous extract of leaves of L. acidissima can be used for the synthesis of zinc oxide nanoparticles. These nanoparticles control the growth of M. tuberculosis and this was confirmed with the microplate alamar blue method. The potential of biogenic zinc oxide nanoparticles may be harnessed as a novel medicine ingredient to combat tuberculosis disease. Copyright © 2016 Asian-African Society for Mycobacteriology. Published by Elsevier Ltd. All rights reserved.

  9. A nanoparticle in plasma

    International Nuclear Information System (INIS)

    Martynenko, Yu. V.; Nagel', M. Yu.; Orlov, M. A.

    2009-01-01

    Charge and energy fluxes onto a nanoparticle under conditions typical of laboratory plasmas are investigated theoretically. Here, by a nanoparticle is meant a grain the size of which is much smaller than both the electron Larmor radius and Debye length and the thermionic emission from which is not limited by the space charge. Under conditions at which thermionic emission plays an important role, the electric potential and temperature T p of a nanoparticle are determined by solving a self-consistent set of equations describing the balance of energy and charge fluxes onto the nanoparticle. It is shown that, when the degree of plasma ionization exceeds a critical level, the potential of the nanoparticle and the energy flux onto it increase with increasing nanoparticle temperature, so that, starting from a certain temperature, the nanoparticle potential becomes positive. The critical degree of ionization starting from which the potential of a nanoparticle is always positive is determined as a function of the plasma density and electron temperature. The nanoparticle temperature T p corresponding to the equilibrium state of a positively charged nanoparticle is found as a function of the electron density for different electron temperatures.

  10. Fast adsorption kinetics of highly dispersed ultrafine nickel/carbon nanoparticles for organic dye removal

    Science.gov (United States)

    Kim, Taek-Seung; Song, Hee Jo; Dar, Mushtaq Ahmad; Lee, Hack-Jun; Kim, Dong-Wan

    2018-05-01

    Magnetic metal/carbon nano-materials are attractive for pollutant adsorption and removal. In this study, ultrafine nickel/carbon nanoparticles are successfully prepared via electrical wire explosion processing in ethanol media for the elimination of pollutant organic dyes such as Rhodamine B and methylene blue in aqueous solutions. High specific surface areas originating from both the nano-sized particles and the existence of carbon on the surface of Ni nanoparticles enhance dye adsorption capacity. In addition to this, the excellent dispersity of Ni/C nanoparticles in aqueous dye solutions leads to superior adsorption rates. The adsorption kinetics for the removal of organic dyes by Ni/C nanoparticles agree with a pseudo-second-order model and follow Freundlich adsorption isotherm behavior.

  11. Air pollution control in practice

    International Nuclear Information System (INIS)

    Baum, F.

    1988-01-01

    The book offers a comprehensive treatment of the subject, from air pollution monitoring and effects on human and animal health, on plants and materials, to pollution reduction measures, practical applications, and legal regulations. It intends to give the air pollution expert a basis for developing practicable solutions. Apart from the 'classic' pollutants, also radioactive air pollution is gone into. (DG) With 366 figs., 190 tabs [de

  12. Absence of auditory 'global interference' in autism.

    Science.gov (United States)

    Foxton, Jessica M; Stewart, Mary E; Barnard, Louise; Rodgers, Jacqui; Young, Allan H; O'Brien, Gregory; Griffiths, Timothy D

    2003-12-01

    There has been considerable recent interest in the cognitive style of individuals with Autism Spectrum Disorder (ASD). One theory, that of weak central coherence, concerns an inability to combine stimulus details into a coherent whole. Here we test this theory in the case of sound patterns, using a new definition of the details (local structure) and the coherent whole (global structure). Thirteen individuals with a diagnosis of autism or Asperger's syndrome and 15 control participants were administered auditory tests, where they were required to match local pitch direction changes between two auditory sequences. When the other local features of the sequence pairs were altered (the actual pitches and relative time points of pitch direction change), the control participants obtained lower scores compared with when these details were left unchanged. This can be attributed to interference from the global structure, defined as the combination of the local auditory details. In contrast, the participants with ASD did not obtain lower scores in the presence of such mismatches. This was attributed to the absence of interference from an auditory coherent whole. The results are consistent with the presence of abnormal interactions between local and global auditory perception in ASD.

  13. Relay self interference minimisation using tapped filter

    KAUST Repository

    Jazzar, Saleh

    2013-05-01

    In this paper we introduce a self interference (SI) estimation and minimisation technique for amplify and forward relays. Relays are used to help forward signals between a transmitter and a receiver. This helps increase the signal coverage and reduce the required transmitted signal power. One problem that faces relays communications is the leaked signal from the relay\\'s output to its input. This will cause an SI problem where the new received signal at the relay\\'s input will be added with the unwanted leaked signal from the relay\\'s output. A Solution is proposed in this paper to estimate and minimise this SI which is based upon using a tapped filter at the destination. To get the optimum weights for this tapped filter, some channel parameters must be estimated first. This is performed blindly at the destination without the need of any training. This channel parameter estimation method is named the blind-self-interference-channel-estimation (BSICE) method. The next step in the proposed solution is to estimate the tapped filter\\'s weights. This is performed by minimising the mean squared error (MSE) at the destination. This proposed method is named the MSE-Optimum Weight (MSE-OW) method. Simulation results are provided in this paper to verify the performance of BSICE and MSE-OW methods. © 2013 IEEE.

  14. Interference pattern period measurement at picometer level

    Science.gov (United States)

    Xiang, Xiansong; Wei, Chunlong; Jia, Wei; Zhou, Changhe; Li, Minkang; Lu, Yancong

    2016-10-01

    To produce large scale gratings by Scanning Beam Interference Lithography (SBIL), a light spot containing grating pattern is generated by two beams interfering, and a scanning stage is used to drive the substrate moving under the light spot. In order to locate the stage at the proper exposure positions, the period of the Interference pattern must be measured accurately. We developed a set of process to obtain the period value of two interfering beams at picometer level. The process includes data acquisition and data analysis. The data is received from a photodiode and a laser interferometer with sub-nanometer resolution. Data analysis differs from conventional analyzing methods like counting wave peaks or using Fourier transform to get the signal period, after a preprocess of filtering and envelope removing, the mean square error is calculated between the received signal and ideal sinusoid waves to find the best-fit frequency, thus an accuracy period value is acquired, this method has a low sensitivity to amplitude noise and a high resolution of frequency. With 405nm laser beams interfering, a pattern period value around 562nm is acquired by employing this process, fitting diagram of the result shows the accuracy of the period value reaches picometer level, which is much higher than the results of conventional methods.

  15. Interference of ascorbic acid with chemical analytes.

    Science.gov (United States)

    Meng, Qing H; Irwin, William C; Fesser, Jennifer; Massey, K Lorne

    2005-11-01

    Ascorbic acid can interfere with methodologies involving redox reactions, while comprehensive studies on main chemistry analysers have not been reported. We therefore attempted to determine the interference of ascorbic acid with analytes on the Beckman Synchron LX20. Various concentrations of ascorbic acid were added to serum, and the serum analytes were measured on the LX20. With a serum ascorbic acid concentration of 12.0 mmol/L, the values for sodium, potassium, calcium and creatinine increased by 43%, 58%, 103% and 26%, respectively (Pascorbic acid concentration of 12.0 mmol/L, the values for chloride, total bilirubin and uric acid decreased by 33%, 62% and 83%, respectively (Pcholesterol, triglyceride, ammonia and lactate. There was no definite influence of ascorbic acid on analytical values for total CO(2), urea, glucose, phosphate, total protein, albumin, amylase, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total iron, unbound iron-binding capacity or magnesium. Ascorbic acid causes a false increase in sodium, potassium, calcium and creatinine results and a false decrease in chloride, total bilirubin, uric acid, total cholesterol, triglyceride, ammonia and lactate results.

  16. Normalized GNSS Interference Pattern Technique for Altimetry

    Directory of Open Access Journals (Sweden)

    Miguel Angel Ribot

    2014-06-01

    Full Text Available It is well known that reflected signals from Global Navigation Satellite Systems (GNSS can be used for altimetry applications, such as monitoring of water levels and determining snow height. Due to the interference of these reflected signals and the motion of satellites in space, the signal-to-noise ratio (SNR measured at the receiver slowly oscillates. The oscillation rate is proportional to the change in the propagation path difference between the direct and reflected signals, which depends on the satellite elevation angle. Assuming a known receiver position, it is possible to compute the distance between the antenna and the surface of reflection from the measured oscillation rate. This technique is usually known as the interference pattern technique (IPT. In this paper, we propose to normalize the measurements in order to derive an alternative model of the SNR variations. From this model, we define a maximum likelihood estimate of the antenna height that reduces the estimation time to a fraction of one period of the SNR variation. We also derive the Cramér–Rao lower bound for the IPT and use it to assess the sensitivity of different parameters to the estimation of the antenna height. Finally, we propose an experimental framework, and we use it to assess our approach with real GPS L1 C/A signals.

  17. Nano-adsorbents for the removal of metallic pollutants from water and wastewater.

    Science.gov (United States)

    Sharma, Y C; Srivastava, V; Singh, V K; Kaul, S N; Weng, C H

    2009-05-01

    Of the variety of adsorbents available for the removal of heavy and toxic metals, activated carbon has been the most popular. A number of minerals, clays and waste materials have been regularly used for the removal of metallic pollutants from water and industrial effluents. Recently there has been emphasis on the application of nanoparticles and nanostructured materials as efficient and viable alternatives to activated carbon. Carbon nanotubes also have been proved effective alternatives for the removal of metallic pollutants from aqueous solutions. Because of their importance from an environmental viewpoint, special emphasis has been given to the removal of the metals Cr, Cd, Hg, Zn, As, and Cu. Separation of the used nanoparticles from aqueous solutions and the health aspects of the separated nanoparticles have also been discussed. A significant number of the latest articles have been critically scanned for the present review to give a vivid picture of these exotic materials for water remediation.

  18. Emerging applications of nanoparticles: Biomedical and environmental

    Science.gov (United States)

    Gulati, Shivani; Sachdeva, M.; Bhasin, K. K.

    2018-05-01

    Nanotechnology finds a wide range of applications from energy production to industrial fabrication processes to biomedical applications. Nanoparticles (NPs) can be engineered to possess unique compositions and functionalities to empower novel tools and techniques that have not existed previously in biomedical research. The unique size and shape dependent physicochemical properties along with their unique spectral and optical properties have prompted the development of a wide variety of potential applications in the field of diagnostics and medicines. In the plethora of scientific and technological fields, environmental safety is also a big concern. For this purpose, nanomaterials have been functionalized to cope up the existing pollution, improving manufacturing methods to reduce the generation of new pollution, and making alternative and more cost effective energy sources.

  19. Effect of Metal Oxides on Plant Germination: Phytotoxicity of Nanoparticles, Bulk Materials, and Metal Ions

    Czech Academy of Sciences Publication Activity Database

    Landa, Přemysl; Cyrusová, Tereza; Jeřábková, J.; Drábek, O.; Vaněk, Tomáš; Podlipná, Radka

    2016-01-01

    Roč. 227, č. 12 (2016), č. článku 448. ISSN 0049-6979 R&D Projects: GA MŠk(CZ) LD14100; GA MŠk LD14125 Institutional support: RVO:61389030 Keywords : zno nanoparticles * pseudokirchneriella-subcapitata * particle solubility * oxidative stress * root-growth * toxicity * aluminum * cuo * ph * cytotoxicity * Nanoparticles * Phytotoxicity * Accumulation * Germination * Sinapis alba Subject RIV: DJ - Water Pollution ; Quality Impact factor: 1.702, year: 2016

  20. Brain damage and behavioural disorders in fish induced by plastic nanoparticles delivered through the food chain

    OpenAIRE

    Mattsson, Karin; Johnson, Elyse V.; Malmendal, Anders; Linse, Sara; Hansson, Lars-Anders; Cedervall, Tommy

    2017-01-01

    The tremendous increases in production of plastic materials has led to an accumulation of plastic pollution worldwide. Many studies have addressed the physical effects of large-sized plastics on organisms, whereas few have focused on plastic nanoparticles, despite their distinct chemical, physical and mechanical properties. Hence our understanding of their effects on ecosystem function, behaviour and metabolism of organisms remains elusive. Here we demonstrate that plastic nanoparticles reduc...

  1. Multifunctional nanoparticles: Analytical prospects

    International Nuclear Information System (INIS)

    Dios, Alejandro Simon de; Diaz-Garcia, Marta Elena

    2010-01-01

    Multifunctional nanoparticles are among the most exciting nanomaterials with promising applications in analytical chemistry. These applications include (bio)sensing, (bio)assays, catalysis and separations. Although most of these applications are based on the magnetic, optical and electrochemical properties of multifunctional nanoparticles, other aspects such as the synergistic effect of the functional groups and the amplification effect associated with the nanoscale dimension have also been observed. Considering not only the nature of the raw material but also the shape, there is a huge variety of nanoparticles. In this review only magnetic, quantum dots, gold nanoparticles, carbon and inorganic nanotubes as well as silica, titania and gadolinium oxide nanoparticles are addressed. This review presents a narrative summary on the use of multifuncional nanoparticles for analytical applications, along with a discussion on some critical challenges existing in the field and possible solutions that have been or are being developed to overcome these challenges.

  2. Nanoparticles and direct immunosuppression

    Science.gov (United States)

    Ngobili, Terrika A

    2016-01-01

    Targeting the immune system with nanomaterials is an intensely active area of research. Specifically, the capability to induce immunosuppression is a promising complement for drug delivery and regenerative medicine therapies. Many novel strategies for immunosuppression rely on nanoparticles as delivery vehicles for small-molecule immunosuppressive compounds. As a consequence, efforts in understanding the mechanisms in which nanoparticles directly interact with the immune system have been overshadowed. The immunological activity of nanoparticles is dependent on the physiochemical properties of the nanoparticles and its subsequent cellular internalization. As the underlying factors for these reactions are elucidated, more nanoparticles may be engineered and evaluated for inducing immunosuppression and complementing immunosuppressive drugs. This review will briefly summarize the state-of-the-art and developments in understanding how nanoparticles induce immunosuppressive responses, compare the inherent properties of nanomaterials which induce these immunological reactions, and comment on the potential for using nanomaterials to modulate and control the immune system. PMID:27229901

  3. Distributed interference alignment iterative algorithms in symmetric wireless network

    Directory of Open Access Journals (Sweden)

    YANG Jingwen

    2015-02-01

    Full Text Available Interference alignment is a novel interference alignment way,which is widely noted all of the world.Interference alignment overlaps interference in the same signal space at receiving terminal by precoding so as to thoroughly eliminate the influence of interference impacted on expected signals,thus making the desire user achieve the maximum degree of freedom.In this paper we research three typical algorithms for realizing interference alignment,including minimizing the leakage interference,maximizing Signal to Interference plus Noise Ratio (SINR and minimizing mean square error(MSE.All of these algorithms utilize the reciprocity of wireless network,and iterate the precoders between original network and the reverse network so as to achieve interference alignment.We use the uplink transmit rate to analyze the performance of these three algorithms.Numerical simulation results show the advantages of these algorithms.which is the foundation for the further study in the future.The feasibility and future of interference alignment are also discussed at last.

  4. Simultaneous Wireless Information and Power Transfer for MIMO Interference Channel Networks Based on Interference Alignment

    Directory of Open Access Journals (Sweden)

    Anming Dong

    2017-09-01

    Full Text Available This paper considers power splitting (PS-based simultaneous wireless information and power transfer (SWIPT for multiple-input multiple-output (MIMO interference channel networks where multiple transceiver pairs share the same frequency spectrum. As the PS model is adopted, an individual receiver splits the received signal into two parts for information decoding (ID and energy harvesting (EH, respectively. Aiming to minimize the total transmit power, transmit precoders, receive filters and PS ratios are jointly designed under a predefined signal-to-interference-plus-noise ratio (SINR and EH constraints. The formulated joint transceiver design and power splitting problem is non-convex and thus difficult to solve directly. In order to effectively obtain its solution, the feasibility conditions of the formulated non-convex problem are first analyzed. Based on the analysis, an iterative algorithm is proposed by alternatively optimizing the transmitters together with the power splitting factors and the receivers based on semidefinite programming (SDP relaxation. Moreover, considering the prohibitive computational cost of the SDP for practical applications, a low-complexity suboptimal scheme is proposed by separately designing interference-suppressing transceivers based on interference alignment (IA and optimizing the transmit power allocation together with splitting factors. The transmit power allocation and receive power splitting problem is then recast as a convex optimization problem and solved efficiently. To further reduce the computational complexity, a low-complexity scheme is proposed by calculating the transmit power allocation and receive PS ratios in closed-form. Simulation results show the effectiveness of the proposed schemes in achieving SWIPT for MIMO interference channel (IC networks.

  5. Lichens as pollution indicators

    Energy Technology Data Exchange (ETDEWEB)

    Rose, F

    1970-01-01

    Although lichens are generally considered to be of little use to man, their sensitivity to air pollution makes them good biological indicators. The author describes how this feature can help to establish relative degrees of air pollution. He notes areas where lichens are reduced in number and vigor, and some in which they have disappeared altogether. He challenges the idea that dryness is responsible, since they have also disappeared from damp woodland areas. Experimental work supports the view that sulfur dioxide is the major factor rather than smoke, although there is no definitive proof. Lichen damage correlates best with mean winter levels of air pollution by SO/sub 2/. 16 references, 1 figure.

  6. Air pollution and lichens

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, B W; Baddeley, M S; Hawksworth, D L [eds.

    1973-01-01

    This volume reflects the particular concern of many biologists for the effects of air pollution and illustrates the special values of lichens as plants suitable for such studies. It brings together contributions from many experts in this field and includes much previously unpublished data, as well as up-to-date review chapters. Emphasis is placed on the logical progression from field observational studies to critical laboratory investigations aimed at elucidating the modes of action of various air pollutants on the living tissues of lichens. The action of such pollutants on vascular plants is also discussed. It is the editors' intention that the book be both a reference volume and an encouragement for further wor

  7. Pollution at Lake Mariut

    International Nuclear Information System (INIS)

    Nour ElDin, H.; Halim, S. N.; Shalby, E.

    2004-01-01

    Lake Mariut, south Alexandria, Egypt suffered in the recent decades from intensive pollution as a result of a continuous discharge of huge amounts of agriculture wastewater that contains a large concentration of the washed pesticides and fertilizers in addition to domestic and industrial untreated wastewater. The over flow from the lake is discharged directly to the sea through El-Max pumping station via EI-Umum drain. Lake Mariout is surrounded by a huge number of different industrial activities and also the desert road is cutting the lake, this means that a huge number of various pollutants cycle through the air and settle down in the lake, by the time and during different seasons these pollutants after accumulation and different chemical interactions will release again from the lake to the surrounding area affecting the surrounding zone

  8. INDOOR AIR POLLUTION

    Directory of Open Access Journals (Sweden)

    Ahmet Soysal

    2007-06-01

    Full Text Available The existance of hazardious materials including biological, chemical, and physical agents such as carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxides, radon, volotile organic compounds, microorganisms in houses and the other non-industrilized buildings have been defined as “indoor air pollution”. Indoor air pollutants could possible arised from inside or outside environment and categorized into six subgroups. Almost 80% Turkish population have living in the urban areas and people in the cities have spending approximetely 90% of their time in the closed enviroments, health problems could increased due to indoor air pollution. Moreover, currently there is no specific regulation on this area. [TAF Prev Med Bull 2007; 6(3.000: 221-226

  9. INDOOR AIR POLLUTION

    Directory of Open Access Journals (Sweden)

    Ahmet Soysal

    2007-06-01

    Full Text Available The existance of hazardious materials including biological, chemical, and physical agents such as carbon dioxide, carbon monoxide, sulphur dioxide, nitrogen oxides, radon, volotile organic compounds, microorganisms in houses and the other non-industrilized buildings have been defined as “indoor air pollution”. Indoor air pollutants could possible arised from inside or outside environment and categorized into six subgroups. Almost 80% Turkish population have living in the urban areas and people in the cities have spending approximetely 90% of their time in the closed enviroments, health problems could increased due to indoor air pollution. Moreover, currently there is no specific regulation on this area. [TAF Prev Med Bull. 2007; 6(3: 221-226

  10. The price of pollution

    International Nuclear Information System (INIS)

    Bleijenberg, A.N.; Davidson, M.D.; Wit, R.

    1998-06-01

    The market does not create a price for environmental pollution for the simple reason that there is no market for the environment. What can be done is to calculate shadow prices for environmental pollution, which is achieved by calculating the price that would arise if there would be a market for the environment. In applying this method, it generally proves to be necessary to base calculations on government environmental targets. Using available research data, the method is used to calculate shadow prices for a number of key pollutants. The present report is based on the CE studies 'Schaduwprijzen Prioriterings Methodiek (SPM)' (1997), commissioned by ICI Holland BV, and 'De prijs van Milieuvervuiling' (1997), commissioned by KNP BT Packaging

  11. Bioremediation of environmental pollutants

    International Nuclear Information System (INIS)

    Madsen, E.L.

    1992-01-01

    This paper reports on disremediation of environmental pollutants. When a tree falls in the forest, when crop residues are left in the fields, and even when spilled gasoline soaks into the ground, microorganisms go to work. Just as humans eat food to sustain life, microorganisms digest nonliving organic materials, using an astounding diversity of enzymes. In the process of deriving carbon and energy for their own use, microorganisms recycle essential nutrients such as nitrogen and phosphorus to the other species with which they share the biosphere. This has thrown many ecosystems into a unsteady state and has threatened human health. Increasing expertise in analytical chemistry and toxicology has contributed to an understanding of the problems of environmental pollution, and remedies are now being sought. Both physical and chemical processes may be essential to pollution-control technologies, but controlled biodegradation also offers significant promise

  12. [How safe are nanoparticles?].

    Science.gov (United States)

    Lademann, J; Meinke, M; Sterry, W; Patzelt, A

    2009-04-01

    Nanoparticles are experiencing an increasing application in dermatology and cosmetics. In both application areas, the requirements of nanoparticles are in most cases widely different. As a component of sunscreens, the nanoparticles are supposed to remain on the skin surface or in the upper most layers of the stratum corneum to protect the skin against UV-radiation of the sun. Whereas, on the other hand, when particulate substances are used as carrier systems for drugs, they have to cross the skin barrier to reach the target sites within the living tissue. We discuss the perspectives and risks of the topical application of nanoparticles.

  13. Pollution from Urban Runoff

    DEFF Research Database (Denmark)

    Hvitved-Jacobsen, Thorkild; Schaarup-Jensen, Kjeld

    1992-01-01

    The main idea of this paper is to establish the following facts: Biodegradable organic matter discharged from combined sewer overflows (CSO) gives rise to an acute effect on the dissolved oxygen (DO) concentration of a river. This acute effect consist of two subeffects: an immediate oxygen deplet...... depletion which takes place in the polluted water volume passing down the river, and a delayed oxygen depletion which is associated with degradation of the organic matter accumulated at the river bottom during the passage of the polluted water volume....

  14. The continental waters pollution

    International Nuclear Information System (INIS)

    Marsily, G. de

    1996-01-01

    This work deals with the continental water pollution. The sewage affect considerably the quality of some rivers water and of some basins. Moreover, a slow and general damage of natural waters has been established. The direct effects on men and on the natural medium (climatic change, aquatic ecosystems, water cycle) are given as well as the protection means (waste processing, the water-bearing bed and underground water protection, the aquatic ecosystems protection and planning) used and future to abate the water pollution. (O.L.). 17 refs., 6 tabs

  15. Layered double hydroxide nanoparticles in gene and drug delivery.

    Science.gov (United States)

    Ladewig, Katharina; Xu, Zhi Ping; Lu, Gao Qing Max

    2009-09-01

    Layered double hydroxides (LDHs) have been known for many decades as catalyst and ceramic precursors, traps for anionic pollutants, catalysts and additives for polymers, but their successful synthesis on the nanometer scale a few years ago opened up a whole new field for their application in nanomedicine. The delivery of drugs and other therapeutic/bioactive molecules (e.g., peptides, proteins, nucleic acids) to mammalian cells is an area of research that is of tremendous importance to medicine and provides manifold applications for any new developments in the area of nanotechnology. Among the many different nanoparticles that have been shown to facilitate gene and/or drug delivery, LDH nanoparticles have attracted particular attention owing to their many desirable properties. This review aims to report recent progress in gene and drug delivery using LDH nanoparticles. It summarizes the advantages and disadvantages of using LDH nanoparticles as carriers for nucleic acids and drugs against the general background of bottlenecks that are encountered by cellular delivery systems. It describes further the models that have been proposed for the internalization of LDH nanoparticles into cells so far and discusses the intracellular fate of the particles and their cargo. The authors offer some remarks on how this field of research will progress in the near future and which challenges need to be overcome before LDH nanoparticles can be used in a clinical setting.

  16. Preparation and characterization of PVPI-coated Fe3O4 nanoparticles as an MRI contrast agent

    International Nuclear Information System (INIS)

    Wang, Guangshuo; Chang, Ying; Wang, Ling; Wei, Zhiyong; Kang, Jianyun; Sang, Lin; Dong, Xufeng; Chen, Guangyi; Wang, Hong; Qi, Min

    2013-01-01

    Polyvinylpyrrolidone-iodine (PVPI)-coated Fe 3 O 4 nanoparticles were prepared by using inverse chemical co-precipitation method, in which the PVPI serves as a stabilizer and dispersant. The wide angle X-ray diffraction (WAXD) and selected area electron diffraction (SAED) results showed that the inverse spinel structure pure phase polycrystalline Fe 3 O 4 was obtained. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results exhibited that the resulted Fe 3 O 4 nanoparticles were roughly spherical in shape with narrow size distribution and homogenous shape. Fourier transform infrared spectroscopy (FTIR) results suggested that PVPI interacted with Fe 3 O 4 via its carbonyl groups. Results of superconducting quantum interference device (SQUID) indicated prepared Fe 3 O 4 nanoparticles exhibited superparamagnetic behavior and high saturation magnetization. T 2 -weighted MRI images of PVPI-coated Fe 3 O 4 nanoparticles showed that the magnetic resonance signal was enhanced significantly with increasing nanoparticles concentration in water at room temperature. These results indicated that the PVPI-coated Fe 3 O 4 nanoparticles had great potential for application in MRI as a T 2 contrast agent. - Highlights: • PVPI-coated Fe 3 O 4 nanoparticles were prepared using inverse co-precipitation method. • Resulted Fe 3 O 4 nanoparticles were roughly spherical in shape with narrow size distribution and homogenous shape. • Prepared Fe 3 O 4 nanoparticles exhibited superparamagnetic behavior. • T 2 -weighted MRI images of PVPI-coated Fe 3 O 4 nanoparticles were obtained

  17. Effects of pollution on freshwater fish

    International Nuclear Information System (INIS)

    McKim, J.M.; Christensen, G.M.; Tucker, J.H.; Benoit, D.A.; Lewis, M.J.

    1974-01-01

    Various aspects of pollution effects on fishes are reviewed under the following headings: methodology; water quality; pesticide pollutants; industrial pollutants; domestic pollutants; radioactive pollutants; and other pollutants. A table is presented to show acute and chronic toxicity of inorganic and organic pollutants to freshwater fish. (U.S.)

  18. RNA interference in designing transgenic crops.

    Science.gov (United States)

    Ali, Nusrat; Datta, Swapan K; Datta, Karabi

    2010-01-01

    RNA interference (RNAi) is a sequence specific gene silencing mechanism, triggered by the introduction of dsRNA leading to mRNA degradation. It helps in switching on and off the targeted gene, which might have significant impact in developmental biology. Discovery of RNAi represents one of the most promising and rapidly advancing frontiers in plant functional genomics and in crop improvement by plant metabolic engineering and also plays an important role in reduction of allergenicity by silencing specific plant allergens. In plants the RNAi technology has been employed successfully in improvement of several plant species- by increasing their nutritional value, overall quality and by conferring resistance against pathogens and diseases. The review gives an insight to the perspective use of the technology in designing crops with innovation, to bring improvement to crop productivity and quality.

  19. On the superposition principle in interference experiments.

    Science.gov (United States)

    Sinha, Aninda; H Vijay, Aravind; Sinha, Urbasi

    2015-05-14

    The superposition principle is usually incorrectly applied in interference experiments. This has recently been investigated through numerics based on Finite Difference Time Domain (FDTD) methods as well as the Feynman path integral formalism. In the current work, we have derived an analytic formula for the Sorkin parameter which can be used to determine the deviation from the application of the principle. We have found excellent agreement between the analytic distribution and those that have been earlier estimated by numerical integration as well as resource intensive FDTD simulations. The analytic handle would be useful for comparing theory with future experiments. It is applicable both to physics based on classical wave equations as well as the non-relativistic Schrödinger equation.

  20. RNA interference: ready to silence cancer?

    Science.gov (United States)

    Mocellin, Simone; Costa, Rodolfo; Nitti, Donato

    2006-01-01

    RNA interference (RNAi) is considered the most promising functional genomics tool recently developed. As in other medical fields, this biotechnology might revolutionize the approach to dissecting the biology of cancer, ultimately speeding up the discovery pace of novel targets suitable for molecularly tailored antitumor therapies. In addition, preclinical results suggest that RNAi itself might be used as a therapeutic weapon. With the aim of illustrating not only the potentials but also the current limitations of RNAi as a tool in the fight against cancer, here we summarize the physiology of RNAi, discuss the main technical issues of RNAi-based gene silencing, and review some of the most interesting preclinical results obtained so far with its implementation in the field of oncology.

  1. Neutron interference by division of wave front

    International Nuclear Information System (INIS)

    Klein, A.G.; Kearney, P.D.; Opat, G.I.; Cimmimo, A.

    1981-01-01

    The highly successful perfect cyrstal neutron interferometer of the type first developed by Bonse and Rauch exhibits interference by amplitude division. It relies on dynamical Bragg diffraction in a highly perfect single crystal to provide the beamsplitting. This type of interferometer, topologically analogous to the Nach-Zehnder interferometer of classical optics, has been employed in a variety of interesting experiments using thermal neutrons. Its shortcomings, however, are its extreme sensitivity to mechanical and thermal disturbances, and its applicability only to wavelegths shorter than the Bragg cutoff (6.27 Angstrom in silicon). The authors discuss a novel type of neutron interferometer which was constructed and tested employing a split cylindrical zone plate with neutrons of 20 Angstrom wavelength. Its performance and relative merits are discussed

  2. Narrowband interference parameterization for sparse Bayesian recovery

    KAUST Repository

    Ali, Anum

    2015-09-11

    This paper addresses the problem of narrowband interference (NBI) in SC-FDMA systems by using tools from compressed sensing and stochastic geometry. The proposed NBI cancellation scheme exploits the frequency domain sparsity of the unknown signal and adopts a Bayesian sparse recovery procedure. This is done by keeping a few randomly chosen sub-carriers data free to sense the NBI signal at the receiver. As Bayesian recovery requires knowledge of some NBI parameters (i.e., mean, variance and sparsity rate), we use tools from stochastic geometry to obtain analytical expressions for the required parameters. Our simulation results validate the analysis and depict suitability of the proposed recovery method for NBI mitigation. © 2015 IEEE.

  3. Metasurface-Enabled Remote Quantum Interference.

    Science.gov (United States)

    Jha, Pankaj K; Ni, Xingjie; Wu, Chihhui; Wang, Yuan; Zhang, Xiang

    2015-07-10

    An anisotropic quantum vacuum (AQV) opens novel pathways for controlling light-matter interaction in quantum optics, condensed matter physics, etc. Here, we theoretically demonstrate a strong AQV over macroscopic distances enabled by a judiciously designed array of subwavelength-scale nanoantennas-a metasurface. We harness the phase-control ability and the polarization-dependent response of the metasurface to achieve strong anisotropy in the decay rate of a quantum emitter located over distances of hundreds of wavelengths. Such an AQV induces quantum interference among radiative decay channels in an atom with orthogonal transitions. Quantum vacuum engineering with metasurfaces holds promise for exploring new paradigms of long-range light-matter interaction for atom optics, solid-state quantum optics, quantum information processing, etc.

  4. Induction of RNA interference in dendritic cells.

    Science.gov (United States)

    Li, Mu; Qian, Hua; Ichim, Thomas E; Ge, Wei-Wen; Popov, Igor A; Rycerz, Katarzyna; Neu, John; White, David; Zhong, Robert; Min, Wei-Ping

    2004-01-01

    Dendritic cells (DC) reside at the center of the immunological universe, possessing the ability both to stimulate and inhibit various types of responses. Tolerogenic/regulatory DC with therapeutic properties can be generated through various means of manipulations in vitro and in vivo. Here we describe several attractive strategies for manipulation of DC using the novel technique of RNA interference (RNAi). Additionally, we overview some of our data regarding yet undescribed characteristics of RNAi in DC such as specific transfection strategies, persistence of gene silencing, and multi-gene silencing. The advantages of using RNAi for DC genetic manipulation gives rise to the promise of generating tailor-made DC that can be used effectively to treat a variety of immunologically mediated diseases.

  5. Grounding and shielding circuits and interference

    CERN Document Server

    Morrison, Ralph

    2016-01-01

    Applies basic field behavior in circuit design and demonstrates how it relates to grounding and shielding requirements and techniques in circuit design This book connects the fundamentals of electromagnetic theory to the problems of interference in all types of electronic design. The text covers power distribution in facilities, mixing of analog and digital circuitry, circuit board layout at high clock rates, and meeting radiation and susceptibility standards. The author examines the grounding and shielding requirements and techniques in circuit design and applies basic physics to circuit behavior. The sixth edition of this book has been updated with new material added throughout the chapters where appropriate. The presentation of the book has also been rearranged in order to reflect the current trends in the field.

  6. Coherent interference effects in SIEM and CBED

    International Nuclear Information System (INIS)

    Cowley, J.M.

    1981-01-01

    The coherent convergent incident beam produced by the field emission gun of a STEM instrument allows the observation of a number of unusual interference effects in the shadow images (SIEM) and convergent beam diffraction (CBED) patterns visible on the detector plane. Shadow images of thin crystals display the electron Ronchigrams having a form sensitive to the defocus and aberrations of the objective lens. For large crystal lattice spacings the Ronchigrams show characteristic ellipses of low contrast. CBED patterns of thin crystal show symmetries and intensities which vary with the position of the incident beam within the unit cell. Discontinuities in the specimen such as the edges of crystals show striking Fresnel diffraction effects in SIEM. In CBED patterns they give rise to the splitting of diffraction spots. If the incident beam is parallel to a smooth face of a small crystal the potential field outside the crystal gives rise to strong refraction effects. (orig.)

  7. TWO-LAYER PHASE COMPENSATING INTERFERENCE SYSTEMS

    Directory of Open Access Journals (Sweden)

    Georgiy V. Nikandrov

    2014-09-01

    Full Text Available The paper deals with creation of optical interferential coatings, giving the possibility to form the wave front without the change of energy characteristics of the incident and reflected radiation. Correction is achieved due to the layer, which thickness is a function of coordinate of an optical element surface. Selection technique is suggested for refractive index materials, forming two-layer interference coating that creates a coating with a constant coefficient of reflection on the surface of the optical element. By this procedure the change of coefficient of reflection for the optical element surface, arising because of the variable thickness is eliminated. Magnesium oxide and zirconium dioxide were used as the film-forming materials. The paper presents experimentally obtained thickness distribution of the layer, which is a part of the phase compensating coating. A new class of optical coatings proposed in the paper can find its application for correcting the form of a wave front.

  8. Increased Stroop interference with better second-language reading skill.

    Science.gov (United States)

    Braet, Wouter; Noppe, Nele; Wagemans, Johan; Op de Beeck, Hans

    2011-03-01

    Skilled readers demonstrate remarkable efficiency in processing written words, unlike beginning readers for whom reading occurs more serially and places higher demands on visual attention. In the present study, we used the Stroop paradigm to investigate the relationship between reading skill and automaticity, in individuals learning a second language with a different orthographic system. Prior studies using this paradigm have presented a mixed picture, finding a positive, a negative, or no relationship between the size of Stroop interference and reading skills. Our results show that Stroop interference in the second language was positively related to reading skill (when controlled for interference in the first language). Furthermore, interference was positively related to objective but not subjective indices of the amount of exposure to the second language. We suggest that the lack of consistency in the results of earlier studies may be due, at least in part, to these studies looking at Stroop interference in isolation, rather than comparing interference between languages.

  9. Analysing Self Interference Cancellation in Full Duplex Radios

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Shafique Ansari, Imran; Berardinelli, Gilberto

    2016-01-01

    Full duplex communication promises a theoretical $100\\%$ throughput gain by doubling the number of simultaneous transmissions. Such compelling gains are conditioned on perfect cancellation of the self interference power resulting from simultaneous transmission and reception. Generally, self...... interference power is modelled as a noise-like constant level interference floor. However, experimental validations have shown that the self interference power is in practice a random variable depending on a number of factors such as the surrounding wireless environment and the degree of interference...... cancellation. In this study, we derive an analytical model for the residual self interference power, and demonstrate various applications of the derived model in analysing the performance of a Full Duplex radio. In general, full duplex communication is found to provide only modest throughput gains over half...

  10. A homology sound-based algorithm for speech signal interference

    Science.gov (United States)

    Jiang, Yi-jiao; Chen, Hou-jin; Li, Ju-peng; Zhang, Zhan-song

    2015-12-01

    Aiming at secure analog speech communication, a homology sound-based algorithm for speech signal interference is proposed in this paper. We first split speech signal into phonetic fragments by a short-term energy method and establish an interference noise cache library with the phonetic fragments. Then we implement the homology sound interference by mixing the randomly selected interferential fragments and the original speech in real time. The computer simulation results indicated that the interference produced by this algorithm has advantages of real time, randomness, and high correlation with the original signal, comparing with the traditional noise interference methods such as white noise interference. After further studies, the proposed algorithm may be readily used in secure speech communication.

  11. Application and research of artificial water mist on photoelectric interference

    Science.gov (United States)

    He, Yuejun; Ren, Baolin

    2018-04-01

    Water mist is a new type of photoelectric interfering material. It can exert a strong interference and shielding effect on infrared light, laser and radar wave through scattering, reflection, refraction and absorption. Based on this, this paper illustrates the application of an artificial high pressure water mist technology in infrared interference system. First, the operating principle of the infrared interference system is introduced. Next, the design principle of self-excited rotary vortex nozzle, the key part of the system, is elaborated. Then, the calculation of the main control parameters of the system is clarified. In the end, the paper verifies interference and shielding effect of the system by experiment. Experiment shows that the interference system can significantly reduce infrared signature of the target, featuring excellent infrared interference performance and high practical value.

  12. Cognitive Aware Interference Mitigation Scheme for LTE Femtocells

    KAUST Repository

    Alqerm, Ismail

    2015-04-21

    Femto-cells deployment in today’s cellular networks came into practice to fulfill the increasing demand for data services. However, interference to other femto and macro-cells users remains an unresolved challenge. In this paper, we propose an interference mitigation scheme to control the cross-tier interference caused by femto-cells to the macro users and the co-tier interference among femtocells. Cognitive radio spectrum sensing capability is utilized to determine the non-occupied channels or the ones that cause minimal interference to the macro users. An awareness based channel allocation scheme is developed with the assistance of the graph-coloring algorithm to assign channels to the femto-cells base stations with power optimization, minimal interference, maximum throughput, and maximum spectrum efficiency. In addition, the scheme exploits negotiation capability to match traffic load and QoS with the channel capacity, and to maintain efficient utilization of the available channels.

  13. Probing two-centre interference in molecular high harmonic generation

    International Nuclear Information System (INIS)

    Vozzi, C; Calegari, F; Benedetti, E; Berlasso, R; Sansone, G; Stagira, S; Nisoli, M; Altucci, C; Velotta, R; Torres, R; Heesel, E; Kajumba, N; Marangos, J P

    2006-01-01

    Two-centre interference in the recombination step of molecular high harmonic generation (HHG) has been probed in CO 2 and O 2 . We report the order dependence of characteristic enhancements or suppressions of high harmonic production in aligned samples of both molecules. In CO 2 , a robust destructive interference was seen consistent with the known separation of the oxygen atoms that are active in HHG. In O 2 , a harmonic enhancement was found indicating constructive interference. A good agreement was found with a simple two-centre interference model that includes the angular distribution function of the sample. The effective momentum of the electron wave was determined from the spectral position of these interferences. Ellipticity-dependent studies in CO 2 clearly show how the destructive interference can be 'switched off' by increasing the degree of ellipticity and thus shifting the effective resonance condition

  14. Quasiparticle interference in unconventional 2D systems.

    Science.gov (United States)

    Chen, Lan; Cheng, Peng; Wu, Kehui

    2017-03-15

    At present, research of 2D systems mainly focuses on two kinds of materials: graphene-like materials and transition-metal dichalcogenides (TMDs). Both of them host unconventional 2D electronic properties: pseudospin and the associated chirality of electrons in graphene-like materials, and spin-valley-coupled electronic structures in the TMDs. These exotic electronic properties have attracted tremendous interest for possible applications in nanodevices in the future. Investigation on the quasiparticle interference (QPI) in 2D systems is an effective way to uncover these properties. In this review, we will begin with a brief introduction to 2D systems, including their atomic structures and electronic bands. Then, we will discuss the formation of Friedel oscillation due to QPI in constant energy contours of electron bands, and show the basic concept of Fourier-transform scanning tunneling microscopy/spectroscopy (FT-STM/STS), which can resolve Friedel oscillation patterns in real space and consequently obtain the QPI patterns in reciprocal space. In the next two parts, we will summarize some pivotal results in the investigation of QPI in graphene and silicene, in which systems the low-energy quasiparticles are described by the massless Dirac equation. The FT-STM experiments show there are two different interference channels (intervalley and intravalley scattering) and backscattering suppression, which associate with the Dirac cones and the chirality of quasiparticles. The monolayer and bilayer graphene on different substrates (SiC and metal surfaces), and the monolayer and multilayer silicene on a Ag(1 1 1) surface will be addressed. The fifth part will introduce the FT-STM research on QPI in TMDs (monolayer and bilayer of WSe 2 ), which allow us to infer the spin texture of both conduction and valence bands, and present spin-valley coupling by tracking allowed and forbidden scattering channels.

  15. Interference Control Modulations Over Conscious Perception

    Directory of Open Access Journals (Sweden)

    Itsaso Colás

    2017-05-01

    Full Text Available The relation between attention and consciousness has been a controversial topic over the last decade. Although there seems to be an agreement on their distinction at the functional level, no consensus has been reached about attentional processes being or not necessary for conscious perception. Previous studies have explored the relation of alerting and orienting systems of attention and conscious perception, but the impact of the anterior executive attention system on conscious access remains unexplored. In the present study, we investigated the behavioral interaction between executive attention and conscious perception, testing control mechanisms both at stimulus-level representation and after error commission. We presented a classical Stroop task, manipulating the proportion of congruent and incongruent trials, and analyzed the effect of reactive and proactive control on the conscious perception of near-threshold stimuli. Reactive control elicited under high proportion congruent conditions influenced participants’ decision criterion, whereas proactive control elicited under low proportion congruent conditions was ineffective in modulating conscious perception. In addition, error commission affected both perceptual sensitivity to detect near-threshold information and response criterion. These results suggest that reactivation of task goals through reactive control strategies in conflict situations impacts decision stages of conscious processing, whereas interference control elicited by error commission impacts both perceptual sensitivity and decision stages of conscious processing. We discuss the implications of our results for the gateway hypothesis about attention and consciousness, as they showed that interference control (both at stimulus-level representation and after error commission can modulate the conscious access of near-threshold stimuli.

  16. Diffractive interference optical analyzer (DiOPTER)

    Science.gov (United States)

    Sasikumar, Harish; Prasad, Vishnu; Pal, Parama; Varma, Manoj M.

    2016-03-01

    This report demonstrates a method for high-resolution refractometric measurements using, what we have termed as, a Diffractive Interference Optical Analyzer (DiOpter). The setup consists of a laser, polarizer, a transparent diffraction grating and Si-photodetectors. The sensor is based on the differential response of diffracted orders to bulk refractive index changes. In these setups, the differential read-out of the diffracted orders suppresses signal drifts and enables time-resolved determination of refractive index changes in the sample cell. A remarkable feature of this device is that under appropriate conditions, the measurement sensitivity of the sensor can be enhanced by more than two orders of magnitude due to interference between multiply reflected diffracted orders. A noise-equivalent limit of detection (LoD) of 6x10-7 RIU was achieved in glass. This work focuses on devices with integrated sample well, made on low-cost PDMS. As the detection methodology is experimentally straightforward, it can be used across a wide array of applications, ranging from detecting changes in surface adsorbates via binding reactions to estimating refractive index (and hence concentration) variations in bulk samples. An exciting prospect of this technique is the potential integration of this device to smartphones using a simple interface based on transmission mode configuration. In a transmission configuration, we were able to achieve an LoD of 4x10-4 RIU which is sufficient to explore several applications in food quality testing and related fields. We are envisioning the future of this platform as a personal handheld optical analyzer for applications ranging from environmental sensing to healthcare and quality testing of food products.

  17. Affective privilege: Asymmetric interference by emotional distracters

    Directory of Open Access Journals (Sweden)

    Crystal eReeck

    2011-09-01

    Full Text Available Numerous theories posit that affectively salient stimuli are privileged in their capacity to capture attention and disrupt ongoing cognition. Two underlying assumptions in this theoretical position are that the potency of affective stimuli transcends task boundaries (i.e., emotional distracters do not have to belong to a current task-set to disrupt processing and that there is an asymmetry between emotional and cognitive processing (i.e., emotional distracters disrupt cognitive processing, but not vice versa. These assumptions have remained largely untested, as common experimental probes of emotion-cognition interaction rarely manipulate task-relevance and only examine one side of the presumed asymmetry of interference. To test these propositions directly, a face-word Stroop protocol was adapted to independently manipulate (a the congruency between target and distracter stimulus features, (b the affective salience of distracter features, and (c the task-relevance of emotional compared to non-emotional target features. A three-way interaction revealed interdependent effects of distracter relevance, congruence, and affective salience. Compared to task-irrelevant distracters, task-relevant congruent distracters facilitated performance and task-relevant incongruent distracters impaired performance, but the latter effect depended on the nature of the target feature and task. Specifically, task-irrelevant emotional distracters resulted in equivalent performance costs as task-relevant non-emotional distracters, whereas task-irrelevant non-emotional distracters did not produce performance costs comparable to those generated by task-relevant emotional distracters. These results document asymmetric cross-task interference effects for affectively salient stimuli, supporting the notion of affective prioritization in human information processing.

  18. Functionally-interdependent shape-switching nanoparticles with controllable properties

    Science.gov (United States)

    Halman, Justin R.; Satterwhite, Emily; Roark, Brandon; Chandler, Morgan; Viard, Mathias; Ivanina, Anna; Bindewald, Eckart; Kasprzak, Wojciech K.; Panigaj, Martin; Bui, My N.; Lu, Jacob S.; Miller, Johann; Khisamutdinov, Emil F.; Shapiro, Bruce A.; Dobrovolskaia, Marina A.

    2017-01-01

    Abstract We introduce a new concept that utilizes cognate nucleic acid nanoparticles which are fully complementary and functionally-interdependent to each other. In the described approach, the physical interaction between sets of designed nanoparticles initiates a rapid isothermal shape change which triggers the activation of multiple functionalities and biological pathways including transcription, energy transfer, functional aptamers and RNA interference. The individual nanoparticles are not active and have controllable kinetics of re-association and fine-tunable chemical and thermodynamic stabilities. Computational algorithms were developed to accurately predict melting temperatures of nanoparticles of various compositions and trace the process of their re-association in silico. Additionally, tunable immunostimulatory properties of described nanoparticles suggest that the particles that do not induce pro-inflammatory cytokines and high levels of interferons can be used as scaffolds to carry therapeutic oligonucleotides, while particles with strong interferon and mild pro-inflammatory cytokine induction may qualify as vaccine adjuvants. The presented concept provides a simple, cost-effective and straightforward model for the development of combinatorial regulation of biological processes in nucleic acid nanotechnology. PMID:28108656

  19. Intersystem Interference Reduction for Overlaid HAPS-Terrestrial CDMA System

    Science.gov (United States)

    Huang, Jeng-Ji; Wang, Wei-Ting; Li, Mingfu; Shiung, David; Ferng, Huei-Wen

    In this letter, we propose that directional antennas, combined with power management, be incorporated to reduce intersystem interference in a shared band overlaid high altitude platform station (HAPS)-terrestrial code division multiple access (CDMA) system. To eliminate the HAPS to terrestrial interference, the HAPS is accessed only via directional antennas under the proposed scheme. By doing so, the uplink power to the HAPS can accordingly be increased, so that the terrestrial to HAPS interference is also effectively suppressed.

  20. Interference of Spin-2 Self-Dual Modes

    OpenAIRE

    Ilha, Anderson; Wotzasek, Clovis

    2001-01-01

    We study the effects of interference between the self-dual and anti self-dual massive modes of the linearized Einstein-Chern-Simons topological gravity. The dual models to be used in the interference process are carefully analyzed with special emphasis on their propagating spectrum. We identify the opposite dual aspects, necessary for the application of the interference formalism on this model. The soldered theory so obtained displays explicitly massive modes of the Proca type. It may also be...