WorldWideScience

Sample records for waterborne particles

  1. Interaction forces between waterborne bacteria and activated carbon particles

    NARCIS (Netherlands)

    Busscher, Henk J.; Dijkstra, Rene J. B.; Langworthy, Don E.; Collias, Dimitris I.; Bjorkquist, David W.; Mitchell, Michael D.; Van der Mei, Henny C.

    2008-01-01

    Activated carbons remove waterborne bacteria from potable water systems through attractive Lifshitz-van der Waals forces despite electrostatic repulsion between negatively charged cells and carbon surfaces. In this paper we quantify the interaction forces between bacteria with negatively and positiv

  2. PREPARATION OF WATERBORNE ULTRAFINE PARTICLES OF EPOXY RESIN BY PHASE INVERSION TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    YANG Zhengzhong; XU Yuanze; WANG Shengjie; YU Hao; CAI Weizhen

    1997-01-01

    Waterborne ultrafine particles of epoxy resin were prepared by phase inversion technique The results of SEM revealed that the particles diameter was in the range of 50 to l()am and the effects on amount of water required at phase inversion point were also dis()ed.

  3. MICRO-PHASE SAEPARATION IN EPOXY RESIN WATERBORNE PARTICLES DURING CURING PROCESS

    Institute of Scientific and Technical Information of China (English)

    Xi-yan Liu; Dong Qiu; Mei-li Guo; Zhen-zhong Yang

    2005-01-01

    Sub-micron sized phenolic epoxy resin waterborne particles were prepared by phase inversion emulsification.Micro-phase separation occurred during the curing process at high temperature. The as-prepared samples possessed one glass transition temperature (Tg) and two exothermal processes during DSC heating scannings. After being thermally treated above the exothermal peak temperature, they possessed two glass transition temperatures with the disappearance of exothermal peaks, whilst a core/shell structure was formed. This was likely related with the outward diffusion of reactive oligomers to the outer layer of particles.

  4. Waterborne, all-polymeric, colloidal ‘raspberry’ particles with controllable hydrophobicity and water droplet adhesion properties

    Energy Technology Data Exchange (ETDEWEB)

    Telford, Andrew M. [School of Chemistry, The University of Sydney, NSW 2006 (Australia); Easton, Christopher D. [CSIRO Manufacturing Flagship, Clayton South, VIC 3169 (Australia); Hawkett, Brian S. [School of Chemistry, The University of Sydney, NSW 2006 (Australia); Neto, Chiara, E-mail: Chiara.neto@sydney.edu.au [School of Chemistry, The University of Sydney, NSW 2006 (Australia)

    2016-03-31

    We present a superhydrophobic coating made from waterborne, all-polymeric ‘raspberry’ particles, composed of a micrometric spherical core decorated with a corona of nanometric spherical particles. As-cast particles produced hydrophobic coatings that were highly adhesive to almost-spherical droplets of water, resembling the properties of some types of rose petals. The coatings could be made slippery to spherical water droplets, like the lotus leaf, by surface activation with air plasma followed by reaction with an alkyl-trichlorosilane. The silanisation of films of latex particles was investigated on two model surfaces (a flat polystyrene film and a monolayer of polystyrene waterborne microparticles) by X-ray photoelectron spectroscopy and water contact angle measurements, and applied to our recently-developed ‘raspberry’ particles to produce a superhydrophobic coating. - Highlights: • We have prepared superhydrophobic films using all-polymeric ‘raspberry’ particles. • We have prepared both ‘rose petal’ and ‘lotus leaf’ surfaces. • We have investigated the silanisation of complex latex particles.

  5. Influence of adhesion to activated carbon particles on the viability of waterborne pathogenic bacteria under flow

    NARCIS (Netherlands)

    van der Mei, Henny C.; Atema-Smit, Jelly; Jager, Debbie; Langworthy, Don E.; Collias, Dimitris I.; Mitchell, Michael D.; Busscher, Henk J.

    2008-01-01

    In rural areas around the world, people often rely on water filtration plants using activated carbon particles for safe water supply. Depending on the carbon surface, adhering microorganisms die or grow to form a biofilm. Assays to assess the efficacy of activated carbons in bacterial removal do not

  6. Removal of two waterborne pathogenic bacterial strains by activated carbon particles prior to and after charge modification

    NARCIS (Netherlands)

    Busscher, Henk J.; Dijkstra, Rene J. B.; Engels, Eefje; Langworthy, Don E.; Collias, Dimitris I.; Bjorkquist, David W.; Mitchell, Michael D.; van der Mei, Henny C.

    2006-01-01

    Waterborne diseases constitute a threat to public health despite costly treatment measures aimed at removing pathogenic microorganisms from potable water supplies. This paper compared the removal of Raoultella terrigena ATCC 33257 and Escherichia coli ATCC 25922 by negatively and positively charged

  7. RHEOLOGICAL BEHAVIOR OF EPOXY RESIN WATERBORNE DISPERSIONS

    Institute of Scientific and Technical Information of China (English)

    Zhen-zhong Yang; Yuan-ze Xu; De-lu Zhao

    2001-01-01

    The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique.Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.``

  8. PREPARATION OF BISPHENOL A EPOXY RESIN WATERBORNE DISPERSIONS BY THE PHASE INVERSION EMULSIFICATION TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    Zhen-zhong Yang; De-lu Zhao

    2000-01-01

    The phase inversion emulsification technique (PIET) is an effective physical method for preparing waterborne dispersions of polymer resins. Some results concerning the preparation of bisphenol A epoxy resin waterborne dispersions by PIET in our laboratory were summarized. Electrical properties, rheological behavior and morphological evolution during phase inversion progress were systematically characterized. The effects of the emulsifier concentration and emulsification temperature on phase inversion progress and the structural features of the waterborne particles were studied as well. The deformation and break up of water drops in a shear field were analyzed in terms of micro-rheology, while the interaction and coalescence dynamics of water drops were discussed in terms of DLVO theory and Smoluchowski effective collision theory,respectively. Based on the experimental results and theoretical analysis, a physical model of phase inversion progress was suggested, by which the effects of the parameters on phase inversion progress and the structural features of the waterborne particles were interpreted and predicted.

  9. Water permeability of pigmented waterborne coatings

    NARCIS (Netherlands)

    Donkers, P.A.J.; Huinink, H.P.; Erich, S.J.F.; Reuvers, N.J.W.; Adan, O.C.G.

    2013-01-01

    Coatings are used in a variety of applications. Last decades more and more coating systems are transforming from solvent to waterborne coating systems. In this study the influence of pigments on the water permeability of a waterborne coating system is studied, with special interest in the possible i

  10. Waterborne outbreak control: which disinfectant?

    Science.gov (United States)

    Akin, E W; Hoff, J C; Lippy, E C

    1982-12-01

    Drinking water disinfection was shown to be an important public health measure around the turn of the century. In the United States, it was perhaps the single most important factor in controlling typhoid fever, a waterborne disease that was rampant throughout the world during the last century. It may also be assumed that disinfection was important in limiting the number of cases of other diseases known to be capable of waterborne transmission, i.e., cholera, amebiasis, shigellosis, salmonellosis, and hepatitis A. Even though modern treatment has eliminated water as a major vehicle of infectious disease transmission, outbreaks still occur. In fact, the annual number has been increasing since 1966. Interruption in chlorination or failure to achieve adequate levels of chlorine residual is the most often identified deficiency of the involved water supplies. This finding indicates that waterborne microbial pathogens remain as a potential health threat and underscores the importance of disinfection. From the outset, chlorination has been the drinking water disinfectant of choice in the country. Numerous studies have demonstrated its ability to inactivate bacterial, viral, and protozoal pathogens when applied under proper conditions. However, the finding that chlorinated organics that are potentially carcinogenic are formed has prompted an evaluation of alternative disinfectants. The viable alternatives to chlorine currently under consideration for widespread use are ozone, chlorine dioxide, and chloramines. In terms of biocidal efficiency, ozone is the most potent of the three. Chlorine dioxide is about the equivalent of free chlorine in the hypochlorous acid form but much more efficient than the hypochlorite form of free chlorine. The chloramines are weaker biocides than hypochlorite. Although this general order of ranking of efficiency holds for diverse types of microorganisms, quantitative comparisons vary with different microorganisms and experimental conditions.

  11. Competitive removal of water-borne copper, zinc and cadmium by a CaCO3-dominated red mud.

    Science.gov (United States)

    Ma, Yingqun; Lin, Chuxia; Jiang, Yuehua; Lu, Wenzhou; Si, Chunhua; Liu, Yong

    2009-12-30

    Batch experiments were conducted to investigate the competitive removal of water-borne Cu, Zn and Cd by a CaCO(3)-dominated red mud. The results show that the water-borne Cu had a higher affinity to the red mud, as compared to the water-borne Zn and Cd. The major mechanism responsible for the preferential retention of Cu by red mud was the formation of atacamite. It is likely that, initially, atacamite was formed mainly through the reaction between CuCl(2) and NaOH. Reaction between CuCl(2) and CaCO(3) to form atacamite became more and more important with the gradual consumption of NaOH. Sequential extraction results show that the water-borne metals were preferentially associated with the NH(2)OH.HCl-extractable fractions at the early stage of the experiment. With increase in the saturation degree of binding sites on red mud particles by the metals, the proportion of HCH(3)COO-extractable Cu fraction increased accordingly. Water-borne Zn and Cd were also increasingly bound in the HCH(3)COO-extractable forms until the metal binding capacity of the red mud was nearly depleted. After the binding sites of red mud particles were saturated, part of the Zn and Cd previously retained by the red mud was displaced by water-borne Cu, resulting in the release of the previously immobilized Zn and Cd to the solution.

  12. A microfluidic laser scattering sensor for label-free detection of waterborne pathogens

    Science.gov (United States)

    Wei, Huang; Yang, Limei; Li, Feng

    2016-10-01

    A microfluidic-based multi-angle laser scattering (MALS) sensor capable of acquiring scattering pattern of single particle is demonstrated. The size and relative refractive index (RI) of polystyrene (PS) microspheres were deduced with accuracies of 60 nm and 0.001 by analyzing the scattering patterns. We measured scattering patterns of waterborne parasites i.e., cryptosporidium parvum (c.parvum) and giardia lamblia (g.lamblia), and some other representative species in 1 L water within 1 hour, and the waterborne parasites were identified with accuracy better than 96% by classification of distinctive scattering patterns with a support-vector-machine (SVM) algorithm. The system provides a promising tool for label-free and rapid detection of waterborne parasites.

  13. Surveillance Systems for Waterborne Protozoa: Beyond Method 1623

    Science.gov (United States)

    1. Brief introduction to waterborne Cryptosporidium and Giardia Historical perspective on detecting Cryptosporidium and Giardia Current detection methodologies 2. US EPA’s waterborne protozoan research program Building a “Protoz...

  14. Surveillance Systems for Waterborne Protozoa Past, Present and Future

    Science.gov (United States)

    OVERVIEW I. Brief introduction to waterborne Cryptosporidium Historical perspective on detecting Cryptosporidium Current detection methodologies II. US EPA’s waterborne protozoan research program Detecting, typing, and tracking sources of Cryptosporidium contami...

  15. Surveillance Systems for Waterborne Protozoa: Beyond Method 1623

    Science.gov (United States)

    1. Brief introduction to waterborne Cryptosporidium and Giardia Historical perspective on detecting Cryptosporidium and Giardia Current detection methodologies 2. US EPA’s waterborne protozoan research program Building a “Protoz...

  16. Surveillance Systems for Waterborne Protozoa Past, Present and Future

    Science.gov (United States)

    OVERVIEW I. Brief introduction to waterborne Cryptosporidium Historical perspective on detecting Cryptosporidium Current detection methodologies II. US EPA’s waterborne protozoan research program Detecting, typing, and tracking sources of Cryptosporidium contami...

  17. Waterborne Pathogens: Detection Methods and Challenges

    Directory of Open Access Journals (Sweden)

    Flor Yazmín Ramírez-Castillo

    2015-05-01

    Full Text Available Waterborne pathogens and related diseases are a major public health concern worldwide, not only by the morbidity and mortality that they cause, but by the high cost that represents their prevention and treatment. These diseases are directly related to environmental deterioration and pollution. Despite the continued efforts to maintain water safety, waterborne outbreaks are still reported globally. Proper assessment of pathogens on water and water quality monitoring are key factors for decision-making regarding water distribution systems’ infrastructure, the choice of best water treatment and prevention waterborne outbreaks. Powerful, sensitive and reproducible diagnostic tools are developed to monitor pathogen contamination in water and be able to detect not only cultivable pathogens but also to detect the occurrence of viable but non-culturable microorganisms as well as the presence of pathogens on biofilms. Quantitative microbial risk assessment (QMRA is a helpful tool to evaluate the scenarios for pathogen contamination that involve surveillance, detection methods, analysis and decision-making. This review aims to present a research outlook on waterborne outbreaks that have occurred in recent years. This review also focuses in the main molecular techniques for detection of waterborne pathogens and the use of QMRA approach to protect public health.

  18. Waterborne Pathogens: Detection Methods and Challenges

    Science.gov (United States)

    Ramírez-Castillo, Flor Yazmín; Loera-Muro, Abraham; Jacques, Mario; Garneau, Philippe; Avelar-González, Francisco Javier; Harel, Josée; Guerrero-Barrera, Alma Lilián

    2015-01-01

    Waterborne pathogens and related diseases are a major public health concern worldwide, not only by the morbidity and mortality that they cause, but by the high cost that represents their prevention and treatment. These diseases are directly related to environmental deterioration and pollution. Despite the continued efforts to maintain water safety, waterborne outbreaks are still reported globally. Proper assessment of pathogens on water and water quality monitoring are key factors for decision-making regarding water distribution systems’ infrastructure, the choice of best water treatment and prevention waterborne outbreaks. Powerful, sensitive and reproducible diagnostic tools are developed to monitor pathogen contamination in water and be able to detect not only cultivable pathogens but also to detect the occurrence of viable but non-culturable microorganisms as well as the presence of pathogens on biofilms. Quantitative microbial risk assessment (QMRA) is a helpful tool to evaluate the scenarios for pathogen contamination that involve surveillance, detection methods, analysis and decision-making. This review aims to present a research outlook on waterborne outbreaks that have occurred in recent years. This review also focuses in the main molecular techniques for detection of waterborne pathogens and the use of QMRA approach to protect public health. PMID:26011827

  19. Advancing waterborne pathogen modelling: lessons from global nutrient export models

    NARCIS (Netherlands)

    Vermeulen, L.C.; Hofstra, N.; Kroeze, C.; Medema, G.J.

    2015-01-01

    Waterborne pathogens cause health problems worldwide. A global waterborne pathogen model could provide valuable new insights for data-sparse regions, by identifying pathogen hotspots and evaluating global change and risk management scenarios. Global waterborne pathogen modelling is not as advanced a

  20. Risk and control of waterborne cryptosporidiosis.

    Science.gov (United States)

    Rose, Joan B; Huffman, Debra E; Gennaccaro, Angela

    2002-06-01

    Cryptosporidium remains at the forefront of studies on waterborne disease transmission and abatement. The impact of environmental land use patterns which contribute animal and human waste, climatic precipitation leading to a strong association with outbreaks, and community infrastructure and water treatment are now recognized as contributing factors in the potential for waterborne spread of the protozoan. Advances in detection methodologies, including the ability to genotype various strains of this organism, have shown that human wastes are often the source of the contamination and cell culture techniques have allowed insight into the viability of the oocyst populations. Currently water treatment has focused on UV and ozone disinfection as most promising for the inactivation of this protozoan pathogen.

  1. Surveillance for Waterborne Disease Outbreaks Associated with Drinking Water, United States 2009-2010

    Science.gov (United States)

    Despite advancements in water management and sanitation, waterborne disease outbreaks continue to occur in the United States. CDC collects data on waterborne disease outbreaks submitted from all states and territories* through the Waterborne Disease and Outbreak Surveillance Syst...

  2. Impact of climate change on waterborne diseases

    OpenAIRE

    Enzo Funari; Maura Manganelli; Luciana Sinisi

    2012-01-01

    Change in climate and water cycle will challenge water availability but it will also increase the exposure to unsafe water. Floods, droughts, heavy storms, changes in rain pattern, increase of temperature and sea level, they all show an increasing trend worldwide and will affect biological, physical and chemical components of water through different paths thus enhancing the risk of waterborne diseases. This paper is intended, through reviewing the available literature, to highlight environmen...

  3. PROGRESS IN PHASE INVERSION EMULSIFICATION FOR EPOXY RESIN WATERBORNE DISPERSIONS

    Institute of Scientific and Technical Information of China (English)

    Zhen-zhong Yang

    2007-01-01

    In this review,our recent work in phase inversion emulsification (PIE)for polymer(especially epoxy resin) waterborne dispersions is summarized.Based on experimental results about PIE process,the physical model is proposed which Can guide the synthesis of the waterborne dispersions such as polymer/nanoparticle composite dispersion.In the presence of a latent curing catalyst,PIE can give a crosslinkable epoxy resin waterborne dispersion.The dispersions can form cured transparent coatings with some unique properties such as UV shielding.They are promising in functional coatings,waterborne resin matrices for composites,and sizing for high performance fibers.

  4. Rheological and Mechanical Behavior of Silk Fibroin Reinforced Waterborne Polyurethane

    Directory of Open Access Journals (Sweden)

    Yongzhen Tao

    2016-03-01

    Full Text Available Waterborne polyurethane (WPU is a versatile and environment-friendly material with growing applications in both industry and academia. Silk fibroin (SF is an attractive material known for its structural, biological and hemocompatible properties. The SF reinforced waterborne polyurethane (WPU is a promising scaffold material for tissue engineering applications. In this work, we report synthesis and characterization of a novel nanocomposite using SF reinforced WPU. The rheological behaviors of WPU and WPU-SF dispersions with different solid contents were investigated with steady shear and dynamic oscillatory tests to evaluate the formation of the cross-linked gel structure. The average particle size and the zeta potential of WPU-SF dispersions with different SF content were examined at 25 °C to investigate the interaction between SF and WPU. FTIR, SEM, TEM and tensile testing were performed to study the effects of SF content on the structural morphology and mechanical properties of the resultant composite films. Experimental results revealed formation of gel network in the WPU dispersions at solid contents more than 17 wt %. The conjugate reaction between the WPU and SF as well as the hydrogen bond between them helped in dispersing the SF powder into the WPU matrix as small aggregates. Addition of SF to the WPU also improved the Young’s modulus from 0.30 to 3.91 MPa, tensile strength from 0.56 to 8.94 MPa, and elongation at break from 1067% to 2480%, as SF was increased up to 5 wt %. Thus, significant strengthening and toughening can be achieved by introducing SF powder into the WPU formulations.

  5. Properties of Waterborne Polyurethane Emulsion Modified by Waterborne Hyperbranched Polyurethane%超支化水性聚氨酯共混改性聚氨酯乳液的性能研究

    Institute of Scientific and Technical Information of China (English)

    田星; 李杰; 罗运军

    2012-01-01

    A acetyl-terminated waterborne hyperbranched polyurethane (AWHBPU) was synthesized by acetic anhydride and waterborne hyperbranched polyurethane (WHBPU). The viscosity, particle size distribution and surface tension of waterborne polyurethane emulsion modified by waterborne hyperbranched polyurethane were studied. Results show that the viscosity of the modified emulsion can be reduced by AWHBPU blending, while non-Newtonian index of the emulsion modified by AWHBPU increases. The test results of particle size distribution and surface tension show that the main cause of the viscosity declining is the particle size increasing, which is induced by AWHBPU accessing to the inside of waterborne polyurethane micelle.%利用乙酸酐对自身可以水分散的超支化水性聚氨酯(WHBPU)进行封端,得到了乙酰基封端的超支化水性聚氨酯(AWHBPU).研究了超支化水性聚氨酯共混改性聚氨酯乳液的剪切黏度、粒径分布以及表面张力.实验结果表明,对WHBPU羟基的封闭可以有效降低共混聚氨酯乳液的黏度;AWHBPU共混乳液偏离牛顿流体程度明显下降;粒径和表面张力测试表明,超支化水性聚氨酯进入胶束内部引起粒径上升是引起黏度下降的重要原因.

  6. A polarized Infrared Spectroscopy Studies of Waterborne Polyurethane Orientation

    Institute of Scientific and Technical Information of China (English)

    Jin Guangkui; Cui Liyan; Yao Hongwei

    2015-01-01

    In this article,we prepare waterborne polyurethane(WPU)by polycarbonate diol,polyoxytetramethylene,dimethylol propionic acid and isophorone diisocyanate.We studied the stretch-oriented behavior of waterborne polyurethane films by universal tensile testing machine and FT-IR. And we analyzed the behavior of polyurethane orientation by infrared dichroism spectroscopy.

  7. A novel broadband waterborne acoustic absorber

    Science.gov (United States)

    Wang, Changxian; Wen, Weibin; Huang, Yixing; Chen, Mingji; Lei, Hongshuai; Fang, Daining

    2016-07-01

    In this paper, we extended the ray tracing theory in polar coordinate system, and originally proposed the Snell-Descartes law in polar coordinates. Based on these theories, a novel broadband waterborne acoustic absorber device was proposed. This device is designed with gradient-distributing materials along radius, which makes the incidence acoustic wave ray warps. The echo reduction effects of this device were investigated by finite element analysis, and the numerical results show that the reflectivity of acoustic wave for the new device is lower than that of homogenous and Alberich layers in almost all frequency 0-30 kHz at the same loss factor.

  8. Preparation of Waterborne Nanoscale Carbon Black Dispersion with Sodium Carboxymethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    YUAN Xia; FANG Kuan-jun

    2006-01-01

    Waterborne nanoscale carbon black dispersion (NCBD) was widely used in inkjet printing, spun-dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose (CMC) as dispersant.Effects of CMC viscosity, ultrasonic time and oxidation with hydrogen peroxide on carbon black (CB) particle size were discussed. The results showed that CB particle size decreased by mechanical agitation while it increased by ultrasonic with the increase of CMC viscosity. Ultrasonic is a more effective method to disperse CB particles than that of mechanical agitation. CB particle size obviously decreased with increasing ultrasonic time and arrived at about 160 nm for 60 min. In addition, oxidation with 2 mol/L of H2O2 and 0.2 wt% of CMC300 reduced CB particle size to 160 nm at 90℃ for 2.5 h.

  9. Blastocystis sp.: waterborne zoonotic organism, a possibility?

    Science.gov (United States)

    Lee, Li Ii; Chye, Tan Tian; Karmacharya, Biraj Man; Govind, Suresh Kumar

    2012-06-28

    Blastocystis sp. is a common intestinal parasite found in faecal sample surveys. Several studies have implicated human-to-human, zoonotic and waterborne transmissions by Blastocystis sp. However, there has been no study providing evidence interlinking these three transmissions in a community. We have previously shown a high prevalence of Blastocystis sp. subtype 4 amongst village dwellers in Bahunipati, Nepal, and the present study extends the observation to assess if the same subtype of Blastocystis sp. occurs in animals they rear and rivers they frequent. Faecal samples were collected from 65 animals. Four river water samples were collected from two rivers. Faecal samples were examined using in vitro cultivation. Blastocystis sp. from animal faecal and river samples were genotyped using seven subtype-specific sequence tagged site (STS) primer-polymerase chain reaction (PCR). Blastocystis sp. infected 15.4% animals with subtype 4 being the predominant genotype (40.0%). Both rivers were contaminated with Blastocystis sp. subtype 1 and subtype 4, which were also detected in humans living in the same village in our previous study. Blastocystis sp. subtype 4 that was detected in buffalo and pigs was also found in the respective family members that reared these animals. This unusually high prevalence of Blastocystis subtype 4 found in village dwellers was also found to be pervasive in the animals they reared and the rivers they frequented implying a strong possibility of waterborne zoonosis for Blastocystis sp.

  10. Preparation, thermal property and morphology analysis of waterborne polyurethane-acrylate

    Science.gov (United States)

    Zhao, Zhenyu; Jing, Zefeng; Qiu, Fengxian; Dai, Yuting; Xu, Jicheng; Yu, Zongping; Yang, Pengfei

    2017-01-01

    A series of waterborne polyurethane-acrylate (WPUA) dispersions were prepared with isophorone diisocyanate (IPDI), polyether polyol (NJ-210), dimethylol propionic acid (DMPA), hydroxyethyl methyl acrylate (HEMA), different proportions of methyl methacrylate (MMA) and ethyl acrylate (MMA and EA) and initiating agent by the emulsion co-polymerization. The structures, thermal properties and morphology of WPUA films were characterized with FT-IR, DSC, SEM and AFM. Performances of the dispersions and films were studied by means of apparent viscidity, particle size and polydispersity, surface tension and mechanical properties. The obtained WPUA have great potential application such as coatings, leather finishing, adhesives, sealants, plastic coatings and wood finishes.

  11. Impact of climate change on waterborne diseases

    Directory of Open Access Journals (Sweden)

    Enzo Funari

    2012-12-01

    Full Text Available Change in climate and water cycle will challenge water availability but it will also increase the exposure to unsafe water. Floods, droughts, heavy storms, changes in rain pattern, increase of temperature and sea level, they all show an increasing trend worldwide and will affect biological, physical and chemical components of water through different paths thus enhancing the risk of waterborne diseases. This paper is intended, through reviewing the available literature, to highlight environmental changes and critical situations caused by floods, drought and warmer temperature that will lead to an increase of exposure to water related pathogens, chemical hazards and cyanotoxins. The final aim is provide knowledge-based elements for more focused adaptation measures.

  12. METAL CORROSION IN WATERBORNE PRESERVATIVE- TREATED WOOD

    Directory of Open Access Journals (Sweden)

    Krisdianto Sugiyanto

    2010-12-01

    Full Text Available The rigidity and firmness of wooden construction and furniture those are joined by metal screws depend on corrosion rate of these metals. This paper examines the weight-loss percentage of metal screws used in wood samples that have been treated with water-borne preser vative (i.e.3% borax boric acid and 3% diffusol CB and concurrently investigates the effect of brake fluid on preventing metal corrosion. Wood samples tested included three acacia and one eucalypts wood species which were grouped into sapwood and heartwood containing samples. Wood samples fastened with metal screws were freely suspended in glass jars that contained 25 ml of sulphuric acid (H2SO4 to keep the humidity rate above 90%. After 12 months, the metal screws lost their weight due to the corrosion brought about by the related factors either in separate individual or in combination, which comprised brake and fluid-dipping , wood species, wood portion (sapwood and heartwood, kinds of preser vatives used. Corrosion rates of metal screws fastened in eucalypts wood sample as indicated by the screw-weight loss (i.e. 5.8% was more severe than that fastened in acacia wood. Furthermore, corrosion rate of metal screws as fixed firmly in sapwood sample proceeded faster than that in heartwood. This might be caused by the higher moisture content in sapwood. On the other hand, corrosion rate of the screws as fastened in waterborne-preser vative-treated wood samples was greater than that in non-preser ved wood due to electrokinetic characteristics and ionic potential exhibited by the preser vative thereby intensif ying the screw-corrosion process. Meanwhile, less severe corrosion was obser ved and recorded on the screws pre-dipped in brake fluid compared to those on the non-dipped screws

  13. Waterborne Epoxy Nanocoatings Modified by Nanoemulsions and Nanoparticles

    National Research Council Canada - National Science Library

    Zhenyu Wang Enhou Han Fuchun Liu Zhouhai Qian Liwei Zhu

    2014-01-01

    .... In the present investigation electrically conductive nanocoatings were prepared by the incorporation of graphite, nano-SiO2 concentrate, acrylic nanoemulsion and fluorocarbon emulsion onto the waterborne epoxy polymer...

  14. Ubiquity of the water-borne pathogens, Cryptosporidium and Giardia ...

    African Journals Online (AJOL)

    drinie

    2001-01-01

    Jan 1, 2001 ... Abstract. The prevalence of the diarrhoea disease caused by the water-borne pathogens ... Giardiapositive cases were recorded in symptomatic. (4.5% and ..... cholera, salmonella, amoebic dysentery, Shigella, or enteropathic.

  15. Conference Report: The 6th International Symposium on Waterborne Pathogens

    Data.gov (United States)

    U.S. Environmental Protection Agency — A review of current literature on the occurrence of waterborne pathogens in DW systems. This dataset is not publicly accessible because: I am using published data...

  16. Progress in Cationic Waterborne Polyurethane%阳离子水性聚氨醋研究进展

    Institute of Scientific and Technical Information of China (English)

    陆金昌; 李仙尹; 欧朝霞; 陈麟

    2011-01-01

    This article has described the development of cationic waterborne polyurethane in aspects of advantages, disadvantages, mechanism of synthesis, the methods of synthesis and the raw materials for synthesis.The influencing factors on properties of cationic waterborne polyurethane were summarized, including the R[n (-NCO)∶n (-OH)]value of prepolymer, the content of hydrophilic chain extender, neutralizer and neutralization degree.Various modification methods for cationic waterborne polyurethane were also introduced,including modification with epoxy resin, hydroxy - terminated silane, polyacrylate and nano - particle.The applications of cationic waterborne polyurethane in coating of leather, adhesive and coating of textile were given, and the development trend of the cationic waterborne polyurethane was described.%介绍了阳离子水性聚氨酯的发展概况,包括阳离子水性聚氨酯的优点,目前存在的主要缺点,合成机理、合成方法及合成原料.简述了预聚物中K[n(-NCO):n(-OH)]值、亲水扩链剂的用量、中和剂的种类及中和度等因素对阳离子水性聚安醋性能的影响.概述了阳离子水性聚氨酷的各种改性方法,包括环氧树脂改性、羟基硅烷改性、丙烯酸酯改性、纳米粒子改性等.介绍了阳离子水性聚氨酯在皮革涂饰剂、胶粘剂、织物整理剂等方面的应用概况,并对其发展方向作了展望.

  17. Synthesis and membrane performance characterization of self-emulsified waterborne nitrocellulose dispersion modified with castor oil

    Energy Technology Data Exchange (ETDEWEB)

    Su, Xiuxia; Zhao, Qingxiao, E-mail: 934481965@qq.com; Zhang, Dan; Dong, Wei

    2015-11-30

    Graphical abstract: - Highlights: • Waterborne nitrocellulose dispersion modified with castor oil (CWNC) was synthesized successfully. • It is a kind of environment-friendly coatings, in which volatile organic content (VOC) is near zero. • Castor oil used as an internal crosslinking agent for WNC improved the properties of the coating. • When the mass fraction of castor oil to total reactants is 7%, emulsion and the coating are of the best comprehensive performance. - Abstract: Waterborne nitrocellulose dispersion modified with castor oil (CWNC) was designed and successfully synthesized by self emulsification and reaction among isophorone diisocyanate (IPDI) trimer, dimethylol propionic acid (DMPA), nitrocellulose (NC) and castor oil (C.O.). The CWNC was characterized by transmission electron microscope (TEM), Fourier transform infrared (FTIR) spectroscopy and thermal gravimetric analysis (TGA), etc. The particle size of CWNC increased with the increase of mass fraction of castor oil to total reactants, ω (C.O.). The morphology of particles is an approximate core–shell structure indicated by TEM. FTIR confirmed that the reactions (i.e. IPDI trimer and castor oil, IPDI trimer and NC) occurred, the NCO groups of IPDI trimer were consumed totally and the backbone of NC was retained. The water contact angle measurements confirmed that introduced castor oil increased hydrophobicity of the film, thereby increasing the contact angle. TGA revealed that the CWNC film had better thermal resistance.

  18. Synthesis and Optical Performances of a Waterborne Polyurethane-Based Polymeric Dye

    Directory of Open Access Journals (Sweden)

    Xianhai Hu

    2015-01-01

    Full Text Available A waterborne polyurethane-based polymeric dye (WPU-CFBB was synthesized by anchoring 1, 4-bis(methylaminoanthraquinone (CFBB to waterborne polyurethane chains. The number molecular weight, glass transition temperature, and average emulsion particle size for the polymeric dye were determined, respectively. This polymeric dye exhibited intriguing optical behaviors. The polymeric dye engendered two new absorption bands centered at about 520 nm and 760 nm if compared with CFBB in UV-vis spectra. The 760 nm peak showed hypsochromic shift with the decrease of average particle sizes. The polymeric dye dramatically demonstrated both hypsochromic and bathochromic effects with increasing temperature. The fluorescence intensity of the polymeric dye was much higher than that of CFBB. It was found that the fluorescence intensities would be enhanced from 20°C to 40°C and then decline from 40°C to 90°C. The fluorescence of the polymeric dye emulsion was very stable and was not sensitive to quenchers.

  19. Degradation of Pollutant and Antibacterial Activity of Waterborne Polyurethane/Doped TiO2 Nanoparticle Hybrid Films

    Institute of Scientific and Technical Information of China (English)

    QIU Shan; DENG Fengxia; XU Shanwen; LIU Peng; MIN Xinmin; MA Fang

    2015-01-01

    The waterborne polyurethane/doped TiO2 nanoparticle hybrid films were prepared. Nd, I doped TiO2 was prepared with a 50 nm particle sizefi rstly. The hybridfi lm was prepared by mixing doped TiO2 with waterborne polyurethane, followed by heat treatment. The presence and nanometric distribution of doped TiO2 nanoparticles in prepared membranes is evident according to SEM images. The photocatalytic activities of doped TiO2 were signifi cantly enhanced compared with pure TiO2 powders. After the hybridfi lm fabrication, the photocatalytic activities were almost the same as the pure catalysts withkMB of 0.046. In the antibacterial testing, the hybridfi lms can inhibitE. coli growth. A signifi cant decrease in membranefl uidity and increase of permeability ofE. coli were observed.

  20. Effects of crosslinking monomer TMP on the properties of waterborne polyurethane%交联单体TMP对水性聚氨酯性能的影响

    Institute of Scientific and Technical Information of China (English)

    高笑飞; 吴明华; 洪国沈; 董青青

    2013-01-01

    The emulsion of self crosslinking waterborne polyurethane was synthesized with isophorone diisocyanate (IPDI) and polyether (N210) as raw material,trimethylolpropane (TMP) as the crosslinking monomer.The effects of dosage of crosslinking monomer TMP on the properties of waterborne polyurethane emulsion and its film were investigated,which was compared with non-crosslinked and external crosslinked type of waterborne polyurethane.The results showed that:when the dosage of TMP was 40%,the particle size of emulsion was small,the stability of polyurethane emulsion was good.The hydrostatic pressure of coated fabric was 239 mm and the washing resistance was 26 times.The fabric coated with self crosslinking waterborne polyurethane had higher hydrostatic pressure and better washing resistance,the performance of self crosslinking waterborne polyurethane could match that of external crosslinking waterborne polyurethane.%以异佛尔酮二异氰酸酯(IPDI)和聚醚(N210)为主要原料,三羟甲基丙烷(TMP)为交联单体,合成自交联型水性聚氨酯乳液.探讨交联单体TMP用量对聚氨酯乳液性能及胶膜性能的影响,并与未交联和外交联型水性聚氨酯进行比较.结果表明:TMP用量为40%时,自交联型水性聚氨酯乳液粒径小,具有较好的稳定性;涂层织物耐静水压为239 mm,耐洗次数可达26次,具有较高的耐静水压和较好的耐洗性,与外交联型水性聚氨酯相当.

  1. Structure, properties and application of a novel low-glossed waterborne polyurethane

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jianjun; Zheng, Wen; Zeng, Wenbo; Zhang, Dongqiao; Peng, Xiaohong, E-mail: pxhpf@scut.edu.cn

    2014-07-01

    Waterborne polyurethane (WPU) with low gloss was prepared successfully and used as surface modifier to adjust the gloss of leather. The structure and morphology of the WPU films were characterized by Fourier transform infrared spectrometer (FTIR), Atomic force microscope (AFM) and Scanning electron microscope (SEM). Then the factors affecting the gloss, light transmittance and water absorption of WPU films including varieties and amount of chain extenders, n{sub NCO}/n{sub OH} molar ratio and 2-[(2-aminoethyl)amino]ethyl sulfonic acid sodium content.etc were studied. Results showed that the WPU film possessed a broad particle size distribution combined with a relatively large particle size. This kind of novel WPU would be widely used in polyvinyl chloride, polyurethane synthetic leather surface.

  2. Detection of coalescing agents in water-borne latex emulsions using an environment sensitive fluorescent probe.

    Science.gov (United States)

    Raja, Tanzeela Nazir; Brouwer, Albert M; Biemans, Koen; Nabuurs, Tijs; Tennebroek, Ronald

    2010-07-30

    In this paper we report the determination of partitioning of coalescing agents (organic co-solvents) in water-borne latex emulsions by means of a fluorescence method. An environment-sensitive fluorescent probe was copolymerized via emulsion polymerization. The presence of organic co-solvents inside the polymer particles is revealed by the photophysical properties of the probe. In particular, the position of the fluorescence emission maximum of co-polymerized can be used to measure the amount of coalescing agent present in the polymer particles. The spectral shifts are shown to be due to the softening of the matrix, rather than to solvation of the probe by the added co-solvent.

  3. Synthesis and characterization of waterborne polyurethane/organic clay nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Zai-feng LI; Sheng-jun WANG; Jin-yan LI

    2008-01-01

    Stable waterborne polyurethane/organic clay latex was synthesized by ultrasonically-assisted mixing with different clay content. Fourier transform infrared (FT-IR) spectra showed that the interaction between NH and C=O was enhanced with low content organic clay loaded. X-ray diffraction (XRD) results implied that the layered organic clay was exfoliated and the crystallization of the hard domain in the waterborne polyurethane (WPU) matrix was enhanced. Transmission electron microscopy (TEM) images show that the layered clay was exfoliated by WPU molecule. The tensile test shows that the mechanical prop-erties were improved by loading organic clay and the desired addition was 1 wt.%.

  4. Synthesis, characterization and fluorescence performance of a waterborne polyurethane-based polymeric dye

    Energy Technology Data Exchange (ETDEWEB)

    Xianhai, Hu, E-mail: hxyh@aiai.edu.cn [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); School of Materials and Chemical Engineering, Building Energy Efficiency Research Institute, Anhui University of Architecture, Hefei 230022 (China); Zhang, Xingyuan, E-mail: zxym@ustc.edu.cn [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Liu, Jin [School of Materials and Chemical Engineering, Building Energy Efficiency Research Institute, Anhui University of Architecture, Hefei 230022 (China); Dai, Jiabing [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei 230026 (China)

    2013-10-15

    A novel anionic waterborne polyurethane-based fluorescent dye WPU-DV26 was synthesized by incorporating the molecular structure of disperse violet 26 (DV26) into the polyurethane chain. The structure of WPU-DV26 was confirmed by means of Fourier transform infrared spectroscopy and UV–vis absorption analysis. Comparing to the UV–vis spectrum of DV26, WPU-DV26 showed a hypsochromic shift from the absorption maxima of 518, 558, 609 nm to 510, 548, 586 nm, respectively. WPU-DV26 can form stable latex in water. The number average molecular weight and its distribution index, and average latex particle size for WPU-DV26 were determined to be 2.33×10{sup 4}, 1.36 and 80 nm, respectively. The improved thermal stability of WPU-DV26 can be attributed to the embedded anthraquinone unit of DV26. It was found that both the intensity and stability of the fluorescence of WPU-DV26 latex were improved significantly compared with those of DV26. -- Highlights: ► A waterborne polyurethane-based polymeric dye was synthesized. ► The fluorescence intensity of WPU-DV26 emulsion was enhanced greatly compared with that of DV26. ► The fluorescence stability of WPU-DV26 emulsion was fine not only for long term storage but also for fluorescence quencher.

  5. Label-free detection and identification of waterborne parasites using a microfluidic multi-angle laser scattering system

    Science.gov (United States)

    Huang, Wei; Yang, Limei; Lei, Lei; Li, Feng

    2017-10-01

    A microfluidic-based multi-angle laser scattering (MALS) system capable of acquiring scattering patterns of a single particle is designed and demonstrated. The system includes a sheathless nozzle microfluidic glass chip, and an on-chip MALS unit being in alignment with the nozzle exit in the chip. The size and relative refractive indices (RI) of polystyrene (PS) microspheres were deduced with accuracies of 60 nm and 0.002 by comparing the experimental scattering patterns with theoretical ones. We measured scattering patterns of waterborne parasites i.e., Cryptosporidium parvum (C.parvum) and Giardia lamblia (G. lamblia), and some other representative species suspended in deionized water at a maximum flow rate of 12 μL/min, and a maximum of 3000 waterborne parasites can be identified within one minute with a mean accuracy higher than 96% by classification of distinctive scattering patterns using a support-vector-machine (SVM) algorithm. The system provides a promising tool for label-free detection of waterborne parasites and other biological contaminants.

  6. Oil-acrylic hybrid latexes as binders for waterborne coatings

    NARCIS (Netherlands)

    Hamersveld, van E.M.S.; Es, van J.; German, A.L.; Cuperus, F.P.; Weissenborn, P.; Hellgren, A.C.

    1999-01-01

    The combination of the characteristics of oil, or alkyd, emulsions and acrylic latexes in a waterborne binder has been the object of various studies in the past. Strategies for combining the positive properties of alkyds, e.g. autoxidative curing, gloss and penetration in wood, with the fast drying

  7. Water-borne protozoa parasites: The Latin American perspective.

    Science.gov (United States)

    Rosado-García, Félix Manuel; Guerrero-Flórez, Milena; Karanis, Gabriele; Hinojosa, María Del Carmen; Karanis, Panagiotis

    2017-07-01

    Health systems, sanitation and water access have certain limitations in nations of Latin America (LA): typical matters of developing countries. Water is often contaminated and therefore unhealthy for the consumers and users. Information on prevalence and detection of waterborne parasitic protozoa are limited or not available in LA. Only few reports have documented in this field during the last forty years and Brazil leads the list, including countries in South America and Mexico within Central America region and Caribbean islands. From 1979 to 2015, 16 outbreaks of waterborne-protozoa, were reported in Latin American countries. T. gondii and C. cayetanensis were the protozoa, which caused more outbreaks and Giardia spp. and Cryptosporidium spp. were the most frequently found protozoa in water samples. On the other hand, Latin America countries have not got a coherent methodology for detection of protozoa in water samples despite whole LA is highly vulnerable to extreme weather events related to waterborne-infections; although Brazil and Colombia have some implemented laws in their surveillance systems. It would be important to coordinate all surveillance systems in between all countries for early detection and measures against waterborne-protozoan and to establish effective and suitable diagnosis tools according to the country's economic strength and particular needs. Copyright © 2017 Elsevier GmbH. All rights reserved.

  8. Waterborne Exophiala species causing disease in cold-blooded animals

    NARCIS (Netherlands)

    de Hoog, G.S.; Vicente, V.A.; Najafzadeh, M.J.; Harrak, M.J.; Badali, H.; Seyedmousavi, S.

    2011-01-01

    The majority of mesophilic waterborne species of the black yeast genus Exophiala (Chaetothyriales) belong to a single clade judging from SSU rDNA data. Most taxa are also found to cause cutaneous or disseminated infections in cold-blooded, water animals, occasionally reaching epidemic proportions. H

  9. Waterborne Exophiala species causing disease in cold-blooded animals

    NARCIS (Netherlands)

    de Hoog, G.S.; Vicente, V.A.; Najafzadeh, M.J.; Harrak, M.J.; Badali, H.; Seyedmousavi, S.

    2012-01-01

    The majority of mesophilic waterborne species of the black yeast genus Exophiala (Chaetothyriales) belong to a single clade judging from SSU rDNA data. Most taxa are also found to cause cutaneous or disseminated infections in cold-blooded, water animals, occasionally reaching epidemic proportions. H

  10. Is Waterborne Disease Still an Issue in the US?

    Centers for Disease Control (CDC) Podcasts

    2012-08-27

    In this podcast, CDC’s Dr. Michael Beach discusses the changing face of waterborne disease in the US over the past century and how healthcare providers can apply this information to their patients.  Created: 8/27/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 10/22/2012.

  11. APPLICATION AND CHARACTERISTICS OF WATERBORNE ROAD MARKING PAINT

    Directory of Open Access Journals (Sweden)

    Darko Babić

    2015-06-01

    Full Text Available Horizontal road markings are one of the essential safety features of modern roadways. All of the utilised systems consist of a pigmented coating containing partially embedded retroreflective elements such as glass beads. In addition to durability and functionality of the road marking, ease of application and effect on human health and environment are primary considerations for their selection. Road marking systems can be divided into plural component materials that cure due to chemical reaction occurring at the site of application, thermoplastics that require heat for application, and paints, drying upon evaporation of the dissolving medium. The focus of this paper is on road marking paints with a special emphasis on contemporary waterborne materials. Over 100 years old solventborne technology furnishes paints that afford consistent application properties under a variety of conditions such as lower temperatures and high humidity. Their environmental and human health impact is significant and durability quite poor. Modern waterborne paints are based on acrylic resins and incorporate developed in the 1990s quick-set chemical mechanism for drying. Under favourable weather conditions, they dry faster as compared to solventborne. However, their known weakness is risk of washout in case of rain and sluggish development of washout resistance at marginal application conditions like high humidity and low temperature. Impact of waterborne paints on human health and environment is very significantly minimised as compared to other materials. Their durability is significantly higher as compared to solvent-based paints. Analysis of characteristics of waterborne road marking paints and preliminary results from their trial application in Croatia are presented herein. Based on the presented comparison with solventborne materials, after results from test application become available, intelligent decisions regarding future use of waterborne road marking paints in

  12. MoS₂ nanoplatelet fillers for enhancement of the properties of waterborne pressure-sensitive adhesives.

    Science.gov (United States)

    Daniloska, Vesna; Keddie, Joseph L; Asua, José M; Tomovska, Radmila

    2014-12-24

    Nanocomposite pressure-sensitive adhesives (PSAs) composed of polyurethane (PU)/(meth)acrylates reinforced with MoS2 nanoplatelets were prepared by blending aqueous dispersions. MoS2 crystals were exfoliated by sonication in water in the presence of poly(vinylpyrrolidone) (PVP, molecular weight of 10,000 g mol(-1)) to prepare an aqueous dispersion. Waterborne colloidal polymer particles (latex) were synthesized by miniemulsion photopolymerization in a continuous tubular reactor. The adhesive and mechanical properties from the resulting nanocomposite films were determined as the MoS2 fraction was increased. A superior balance of viscoelastic properties was achieved with 0.25 wt % loading of the MoS2 nanoplatelets, leading to a tack adhesion energy that was three times greater than that for the original PSA.

  13. Waterborne hyperbranched alkyd-acrylic resin obtained by mini emulsion polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Murillo, Edwin, E-mail: edwinalbertomurillo@gmail.com [Grupo de Investigacion en Materiales Polimericos (GIMAPOL), Universidad Francisco de Paula Santander, San Jose de Cucuta (Colombia); Lopez, Betty [Grupo de Investigacion en Ciencia de los Materiales, Universidad de Antioquia, Calle, Medellin (Colombia)

    2016-10-15

    Four waterborne hyper branched alkyd-acrylic resins (HBRAA) were synthesized by mini emulsion polymerization from a hyper branched alkyd resin (HBR), methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA), by using benzoyl peroxide (BPO) and ammonium persulfate (AP) as initiators. The reaction between HBR and acrylic monomers was evidenced by differential scanning calorimetric (DSC), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The conversion percentage, glass transition temperature (T{sub g}), content of acrylic polymer (determined by soxhlet extraction) and molecular weight increased with the content of acrylic monomers used in the synthesis. The main structure formed during the synthesis was the HBRAA. The analysis by dynamic light scattering (DLS) showed that the particle size distribution of HBRAA2, HBRAA3 and HBRAA4 resins were mainly mono modal. The film properties (gloss, flexibility, adhesion and drying time) of the HBRAA were good. (author)

  14. Climate, Waterborne Disease, and Public Health in Eastern Russia

    Science.gov (United States)

    Tirrell, Andrew

    2013-04-01

    As global temperatures rise, waterborne diseases have expanded their ranges northward. Exposure to new diseases is especially threatening to isolated communities, whose remote locations and lack of health resources and infrastructure leave them particularly vulnerable. For this project, a time series analysis of existing data will be used to assess temporal and spatial associations between long-term, seasonal and short-term weather variability, and waterborne infectious diseases in several Siberian communities. Building on these associations, we will generate estimates of future changes in infectious disease patterns based upon existing forecasts of climate change and likely increases in extreme weather events in eastern Russia. Finally, we will contemplate the public health implications of these findings and offer appropriate policy recommendations. One of our policy aims will be to identify easily measured water quality indicators that may serve as useful proxies for environmental health in rural, especially indigenous, communities.

  15. Controlling film topography to form highly hydrophobic waterborne coatings.

    Science.gov (United States)

    López, Ana B; de la Cal, José C; Asua, José M

    2016-08-17

    Coatings have a tremendous impact on economy as they reduce corrosion that has an estimated cost of 3% of the world's GDP. Hydrophobic coatings are particularly efficient for this purpose and the challenge is to produce cost effective and environmentally friendly, highly hydrophobic, cohesive and non-porous coatings applicable to large and irregular surfaces. This work shows that this goal can be achieved by forming wrinkles on the surface of waterborne coatings through fine-tuning of the film forming conditions. The proof of concept was demonstrated by using waterborne dispersions of copolymers of 1H,1H,2H,2H-perfluorodecyl acrylate and 2-ethylhexyl acrylate, and using the temperature and hardness of the copolymer as control variables during film formation. This allowed the formation of transparent films with a wrinkled surface that had a contact angle of 133°, which represents an increase of 20° with respect to the film cast under standard conditions.

  16. Metagenomic Sequencing for Surveillance of Food- and Waterborne Viral Diseases

    Science.gov (United States)

    Nieuwenhuijse, David F.; Koopmans, Marion P. G.

    2017-01-01

    A plethora of viruses can be transmitted by the food- and waterborne route. However, their recognition is challenging because of the variety of viruses, heterogeneity of symptoms, the lack of awareness of clinicians, and limited surveillance efforts. Classical food- and waterborne viral disease outbreaks are mainly caused by caliciviruses, but the source of the virus is often not known and the foodborne mode of transmission is difficult to discriminate from human-to-human transmission. Atypical food- and waterborne viral disease can be caused by viruses such as hepatitis A and hepatitis E. In addition, a source of novel emerging viruses with a potential to spread via the food- and waterborne route is the repeated interaction of humans with wildlife. Wildlife-to-human adaptation may give rise to self- limiting outbreaks in some cases, but when fully adjusted to the human host can be devastating. Metagenomic sequencing has been investigated as a promising solution for surveillance purposes as it detects all viruses in a single protocol, delivers additional genomic information for outbreak tracing, and detects novel unknown viruses. Nevertheless, several issues must be addressed to apply metagenomic sequencing in surveillance. First, sample preparation is difficult since the genomic material of viruses is generally overshadowed by host- and bacterial genomes. Second, several data analysis issues hamper the efficient, robust, and automated processing of metagenomic data. Third, interpretation of metagenomic data is hard, because of the lack of general knowledge of the virome in the food chain and the environment. Further developments in virus-specific nucleic acid extraction methods, bioinformatic data processing applications, and unifying data visualization tools are needed to gain insightful surveillance knowledge from suspect food samples. PMID:28261185

  17. 水性聚氨酯的研究进展%Research Progress of Waterborne Polyurethane

    Institute of Scientific and Technical Information of China (English)

    刘雪梅

    2013-01-01

    The significances of waterborne polyurethane were analyzed, and the research progress of single-component waterborne polyurethane coatings and two-component waterborne polyurethane coatings were introduced.%主要分析了聚氨酯水性化的意义,并介绍了单组分水性聚氨酯涂料与双组分水性聚氨酯涂料的研究进展。

  18. Zoonotic Transmission of Waterborne Disease: A Mathematical Model.

    Science.gov (United States)

    Waters, Edward K; Hamilton, Andrew J; Sidhu, Harvinder S; Sidhu, Leesa A; Dunbar, Michelle

    2016-01-01

    Waterborne parasites that infect both humans and animals are common causes of diarrhoeal illness, but the relative importance of transmission between humans and animals and vice versa remains poorly understood. Transmission of infection from animals to humans via environmental reservoirs, such as water sources, has attracted attention as a potential source of endemic and epidemic infections, but existing mathematical models of waterborne disease transmission have limitations for studying this phenomenon, as they only consider contamination of environmental reservoirs by humans. This paper develops a mathematical model that represents the transmission of waterborne parasites within and between both animal and human populations. It also improves upon existing models by including animal contamination of water sources explicitly. Linear stability analysis and simulation results, using realistic parameter values to describe Giardia transmission in rural Australia, show that endemic infection of an animal host with zoonotic protozoa can result in endemic infection in human hosts, even in the absence of person-to-person transmission. These results imply that zoonotic transmission via environmental reservoirs is important.

  19. Separation and concentration of water-borne contaminants utilizing insulator-based dielectrophoresis.

    Energy Technology Data Exchange (ETDEWEB)

    Lapizco-Encinas, Blanca Hazalia; Fiechtner, Gregory J.; Cummings, Eric B.; Davalos, Rafael V.; Kanouff, Michael P.; Simmons, Blake Alexander; McGraw, Gregory J.; Salmi, Allen J.; Ceremuga, Joseph T.; Fintschenko, Yolanda

    2006-01-01

    This report focuses on and presents the capabilities of insulator-based dielectrophoresis (iDEP) microdevices for the concentration and removal of water-borne bacteria, spores and inert particles. The dielectrophoretic behavior exhibited by the different particles of interest (both biological and inert) in each of these systems was observed to be a function of both the applied electric field and the characteristics of the particle, such as size, shape, and conductivity. The results obtained illustrate the potential of glass and polymer-based iDEP devices to act as a concentrator for a front-end device with significant homeland security and industrial applications for the threat analysis of bacteria, spores, and viruses. We observed that the polymeric devices exhibit the same iDEP behavior and efficacy in the field of use as their glass counterparts, but with the added benefit of being easily mass fabricated and developed in a variety of multi-scale formats that will allow for the realization of a truly high-throughput device. These results also demonstrate that the operating characteristics of the device can be tailored through the device fabrication technique utilized and the magnitude of the electric field gradient created within the insulating structures. We have developed systems capable of handling numerous flow rates and sample volume requirements, and have produced a deployable system suitable for use in any laboratory, industrial, or clinical setting.

  20. 高固含量水性聚氨酯的合成研究进展%Progress in the Synthesis of Waterborne Polyurethane with High Solid Content

    Institute of Scientific and Technical Information of China (English)

    曲家乐; 王全杰; 刘立忠

    2012-01-01

    对水性聚氨酯的发展做了简要综述,并基于球型密堆积数学模型对影响水性聚氨酯乳液粒径以及粒径分布的各种因素做了论述.最后总结了各种新型的合成方法,并进一步对高固含量水性聚氨酯的合成做了展望.%The development of waterborne polyurethane was briefly overviewed and the various factors of infecting the wate.r-based polyurethane emulsion particle size and size distribution were discussed-basing on the mathematical model of ball close to the accumulation. At last a variety of new synthetic methods were concluded, and then the synthesis of waterborne polyurethane with high solid content was prospected.

  1. Surveillance for Waterborne Disease Outbreaks and Other Health Events Associated with Recreational Water -United States, 2007-2008

    Science.gov (United States)

    Background: Since 1978, CDC, EPA, and the Council of State and Territorial Epidemiologists have collaborated on the Waterborne Disease and Outbreak Surveillance System (WBDOSS) to capture data on waterborne disease outbreaks associated with recreational water. WBDOSS is the prima...

  2. EFFECT OF SILICA NANOPARTICLES ON PROPERTIES OF WATERBORNE POLYURETHANES

    Institute of Scientific and Technical Information of China (English)

    Xiao-hu Qiang; Li-bang Feng; Yan-ping Wang; Shun-hua Wang

    2012-01-01

    Waterborne polyurethane composites containing silica nanoparticles are synthesized successfully via the in situ polymerization.The structure,thermal stability,surface hardness,tensile strength,UV-Vis absorbance,dynamic mechanical properties and chemicals resistance of the resulting composites are investigated by FTIR,TEM,TGA,UV-Vis,DMA and chemicals soakage measurements.Results show that polyurethane molecules and silica nanoparticles are linked with covalent bonds.As a result,physical properties of polyurethane composites,such as thermal stability,surface hardness,weather and chemicals resistance are all improved when an appropriate concentration of silica nanoparticles are incorporated.

  3. Differential media for quantitative recovery of waterborne Aeromonas hydrophila.

    Science.gov (United States)

    Handfield, M; Simard, P; Letarte, R

    1996-09-01

    Because of the ubiquity of Aeromonas spp., their prevalence in drinking water, and the increasing number of reports on Aeromonas sp.-related infections, a standard method for routine and quantitative recovery had to be defined. On the basis of a survey of 10 media for recovery analysis and subsequent differentiation assays in mixed cultures, we conclude that ampicillin-dextrin agar performed the best for the recovery of Aeromonas spp. in drinking water and the differentiation by simple criteria of that genus from other common waterborne bacteria.

  4. Synthesis and characterization of a novel waterborne stilbene-based polyurethane fluorescent brightener

    Institute of Scientific and Technical Information of China (English)

    Xian Hai Hu; Xing Yuan Zhang; Jia Bin Dai

    2011-01-01

    A novel waterborne stilbene-based polyurethane fluorescent brightener dispersion WPU-VBL was synthesized by incorporating chemically disodium 4,4'-bis[(4-anilino-6-hydroxyethylamino-1,3,5-triazin-2-y1)amino]stilbene-2,2'-disulphonate (VBL) into the polyurethane chain using isophorone diisocyanate, poly(propylene glycol) and 2,2-dimethylol propionic acid. The structure of WPU-VBL was confirmed by means of Fourier transform infrared spectroscopy. The UV-vis absorption analysis showed a hypsochromic shift of 16 nm when VBL was blocked into polyurethane chain. Number average molecular weight of 2.1 × 104, molecular weight distribution of 2.1 and average latex particle size of about 70 nm for WPU-VBL were determined based on the analysis of gel permeation chromatography and laser particle size analyzer. It was found that the fluorescence intensity of WPU-VBL was prominently enhanced because of the micro-circumstance of VBL and the fluorescence of WPU-VBL was very stable. ? 2011 Xing Yuan Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  5. Detection of Waterborne Viruses Using High Affinity Molecularly Imprinted Polymers.

    Science.gov (United States)

    Altintas, Zeynep; Gittens, Micah; Guerreiro, Antonio; Thompson, Katy-Anne; Walker, Jimmy; Piletsky, Sergey; Tothill, Ibtisam E

    2015-07-07

    Molecularly imprinted polymers (MIPs) are artificial receptor ligands which can recognize and specifically bind to a target molecule. They are more resistant to chemical and biological damage and inactivation than antibodies. Therefore, target specific-MIP nanoparticles are aimed to develop and implemented to biosensors for the detection of biological toxic agents such as viruses, bacteria, and fungi toxins that cause many diseases and death due to the environmental contamination. For the first time, a molecularly imprinted polymer (MIP) targeting the bacteriophage MS2 as the template was investigated using a novel solid-phase synthesis method to obtain the artificial affinity ligand for the detection and removal of waterborne viruses through optical-based sensors. A high affinity between the artificial ligand and the target was found, and a regenerative MIP-based virus detection assay was successfully developed using a new surface plasmon resonance (SPR)-biosensor which provides an alternative technology for the specific detection and removal of waterborne viruses that lead to high disease and death rates all over the world.

  6. [Biology, epidemiology and diagnostics of pathogenic waterborne protozoan parasites].

    Science.gov (United States)

    Leońska-Duniec, Agata; Adamska, Małgorzata

    2010-01-01

    Cryptosporidium, Giardia intestinalis, Cyclospora cayetanensis, Isosopra belli and micropsoridia are the most important and common pathogens found in humans and many other species of vertebrates. In humans, mainly in immunocompromised patients, children, pregnant women and elderly people, they are the most frequently identified protozoan parasites causing gastrointestinal disease worldwide. These pathogens have several transmission routes, including anthroponotic and zoonotic transmission. What is more, in many cases of epidemics caused by mentioned pathogens the major cause of infection was contaminated with these organisms water and food. In spite of many existing regulations of clearing and making use of drinking water supplies and recreational water, cosmopolitan protozoan parasites are still the danger of public health. These organisms are responsible for many waterborne outbreaks worldwide. Light microscopy and immunofluorescence assay have been used to identify these organisms in most laboratories. However, these traditional techniques have major limitations in the specific diagnosis, these methods are not sensitive enough to detect cysts or oocysts in environmental samples, so the new molecular tools must be applied. Recently, PCR-based techniques have been developed for detection and genetic characterization of the different species and population variants of protozoan parasites is central to the prevention, surveillance and control of gastrointestinal diseases. In this review were characterized biology, epidemiology and the progress in technology for detection and surveillance of the most important waterborne protozoan parasites.

  7. Extreme water-related weather events and waterborne disease.

    Science.gov (United States)

    Cann, K F; Thomas, D Rh; Salmon, R L; Wyn-Jones, A P; Kay, D

    2013-04-01

    Global climate change is expected to affect the frequency, intensity and duration of extreme water-related weather events such as excessive precipitation, floods, and drought. We conducted a systematic review to examine waterborne outbreaks following such events and explored their distribution between the different types of extreme water-related weather events. Four medical and meteorological databases (Medline, Embase, GeoRef, PubMed) and a global electronic reporting system (ProMED) were searched, from 1910 to 2010. Eighty-seven waterborne outbreaks involving extreme water-related weather events were identified and included, alongside 235 ProMED reports. Heavy rainfall and flooding were the most common events preceding outbreaks associated with extreme weather and were reported in 55·2% and 52·9% of accounts, respectively. The most common pathogens reported in these outbreaks were Vibrio spp. (21·6%) and Leptospira spp. (12·7%). Outbreaks following extreme water-related weather events were often the result of contamination of the drinking-water supply (53·7%). Differences in reporting of outbreaks were seen between the scientific literature and ProMED. Extreme water-related weather events represent a risk to public health in both developed and developing countries, but impact will be disproportionate and likely to compound existing health disparities.

  8. Synthesis of waterborne polyurethane containing alkoxysilane side groups and the properties of the hybrid coating films

    Science.gov (United States)

    Li, Qi; Guo, Longhai; Qiu, Teng; Xiao, Weidong; Du, Dianxing; Li, Xiaoyu

    2016-07-01

    A series of waterborne polyurethane (WPU) containing alkoxysilane side groups were synthesized by using the dihydroxy functionalized alkoxysilane. The diol with trimethoxysilane groups at the side chains was synthesized via Michael addition between 3-(methacryloxypropyl)trimethoxysilane (MAPTS) and diethanolamine (DEA). The silane diol was applied as the chain extender for the NCO-endcapped prepolymer of isophorone diisocyanate, polycarbonate diol, 2,2-bis(hydroxymethyl) butyric acid and 1,4-butanediol. The products with the silane content varied from 1.2 to 16.5 wt% were dispersed in water after neutralization. The effect of the silane diol on the particle size and morphology of the WPU dispersion was studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. X-ray photoelectron spectroscopy (XPS) characterization was carried out on the coating film of the WPU, revealing that the long flexible side chain is favorable for the silane components to emigrate toward the film surface and crosslink during the film formation process. As a result, both the surface contact angle to water and water adsorption of the WPU coating films increased with the silane content. Furthermore, the mechanical properties including the modulus and tensile strength of the films were also improved by the incorporation of silane diol.

  9. Hybrid thin films derived from UV-curable acrylate-modified waterborne polyurethane and monodispersed colloidal silica

    Directory of Open Access Journals (Sweden)

    C. H. Yang

    2012-01-01

    Full Text Available Hybrid thin films containing nano-sized inorganic domains were synthesized from UV-curable acrylate-modified waterborne polyurethane (WPU-AC and monodispersed colloidal silica with coupling agent. The coupling agent, 3-(trimethoxysilylpropyl methacrylate (MSMA, was bonded onto colloidal silica first, and then mixed with WPU-AC to form a precursor solution. This precursor was spin coated, dried and UV-cured to generate the hybrid films. The silica content in the hybrid thin films was varied from 0 to 30 wt%. Experimental results showed the aggregation of silica particles in the hybrid films. Thus, the silica domain in the hybrid films was varied from 30 to 50 nm by the different ratios of MSMAsilica to WPU-AC. The prepared hybrid films from the crosslinked WPU-AC/MSMA-silica showed much better thermal stability and mechanical properties than pure WPU-AC.

  10. PREPARATION AND CHARACTERIZATION OF WATERBORNE POLYURETHANES MODIFIED WITH BIS(3-(1-METHOXY-2-HYDROXY- PROPOXY)PROPYL) TERMINATED POLYSILOXANES

    Institute of Scientific and Technical Information of China (English)

    Xiao-li Zhu; Xu-bao Jiang; Zhi-guo Zhang; Xiang-zheng Kong

    2011-01-01

    Polyurethanes (PU) were prepared using toluene diisocyanate, polypropylene glycol, ethylene glycol, dimethylolpropionic acid and triethylamine, and a siloxane modified PU (PSU) was obtained through reaction of the PU prepolymers with bis(3-(l-methoxy-2-hydroxypropoxy)propyl) terminated polysiloxanes (PMTS) of different molecular weight, specifically designed for this purpose. Results showed that, with increases in molecular weight of PMTS and its content, viscosity of the final PSU latexes decreased; phase separation of the incorporated PMTS in PSU films increased; the average particle sizes of the latexes varied between 110 nm and 330 nm, and the surface tension in the final latexes was relatively constant regardless of PMTS amount and its molecular weight. It was likely that copoIymerized polysiloxanes had trend to enrich on top of the film when PMTS molecular weight was around 2000 and its content above 5 wt%. In general, PMTS modified polyurethane films showed higher performance than those from unmodified waterborne polyurethane latexes.

  11. Waterborne polyurethanes: influence of chain extender in ftir spectra profiles

    Science.gov (United States)

    Delpech, Marcia; Miranda, Gisele

    2012-06-01

    Non-polluting systems based on waterborne polyurethanes (wPU) and poly(urethane-urea)s (wPUU) were synthesized employing poly(propylene glycol) (PPG), dimethylolpropionic acid (DMPA) and 4,4'-dicyclohexylmethane diisocyanate (HMDI) as monomers. In the formulations, the length and the proportion of the soft segments were varied. Three types of chain extenders were employed: ethylene glycol (EG), producing urethane linkages; and ethylenediamine (EDA) and hydrazine (HYD), forming urea linkages. Cast films obtained from wPU and wPUU, monomers and prepolymers were analyzed by Fourier transform infrared spectrometry (FTIR). The profile of carbonyl absorption bands obtained for the films showed some remarkable differences depending on the formulation. The bands were split into two parts, which were directly related to the tendency of hydrogen bond formation. The length of soft segment, the amount of rigid portions and the presence of urea linkages showed a marked influence in both intensity and frequency absorption of the bands.

  12. Comparison of supervised machine learning algorithms for waterborne pathogen detection using mobile phone fluorescence microscopy

    Science.gov (United States)

    Ceylan Koydemir, Hatice; Feng, Steve; Liang, Kyle; Nadkarni, Rohan; Benien, Parul; Ozcan, Aydogan

    2017-06-01

    Giardia lamblia is a waterborne parasite that affects millions of people every year worldwide, causing a diarrheal illness known as giardiasis. Timely detection of the presence of the cysts of this parasite in drinking water is important to prevent the spread of the disease, especially in resource-limited settings. Here we provide extended experimental testing and evaluation of the performance and repeatability of a field-portable and cost-effective microscopy platform for automated detection and counting of Giardia cysts in water samples, including tap water, non-potable water, and pond water. This compact platform is based on our previous work, and is composed of a smartphone-based fluorescence microscope, a disposable sample processing cassette, and a custom-developed smartphone application. Our mobile phone microscope has a large field of view of 0.8 cm2 and weighs only 180 g, excluding the phone. A custom-developed smartphone application provides a user-friendly graphical interface, guiding the users to capture a fluorescence image of the sample filter membrane and analyze it automatically at our servers using an image processing algorithm and training data, consisting of >30,000 images of cysts and >100,000 images of other fluorescent particles that are captured, including, e.g. dust. The total time that it takes from sample preparation to automated cyst counting is less than an hour for each 10 ml of water sample that is tested. We compared the sensitivity and the specificity of our platform using multiple supervised classification models, including support vector machines and nearest neighbors, and demonstrated that a bootstrap aggregating (i.e. bagging) approach using raw image file format provides the best performance for automated detection of Giardia cysts. We evaluated the performance of this machine learning enabled pathogen detection device with water samples taken from different sources (e.g. tap water, non-potable water, pond water) and achieved a

  13. Comparison of supervised machine learning algorithms for waterborne pathogen detection using mobile phone fluorescence microscopy

    Directory of Open Access Journals (Sweden)

    Ceylan Koydemir Hatice

    2017-06-01

    Full Text Available Giardia lamblia is a waterborne parasite that affects millions of people every year worldwide, causing a diarrheal illness known as giardiasis. Timely detection of the presence of the cysts of this parasite in drinking water is important to prevent the spread of the disease, especially in resource-limited settings. Here we provide extended experimental testing and evaluation of the performance and repeatability of a field-portable and cost-effective microscopy platform for automated detection and counting of Giardia cysts in water samples, including tap water, non-potable water, and pond water. This compact platform is based on our previous work, and is composed of a smartphone-based fluorescence microscope, a disposable sample processing cassette, and a custom-developed smartphone application. Our mobile phone microscope has a large field of view of ~0.8 cm2 and weighs only ~180 g, excluding the phone. A custom-developed smartphone application provides a user-friendly graphical interface, guiding the users to capture a fluorescence image of the sample filter membrane and analyze it automatically at our servers using an image processing algorithm and training data, consisting of >30,000 images of cysts and >100,000 images of other fluorescent particles that are captured, including, e.g. dust. The total time that it takes from sample preparation to automated cyst counting is less than an hour for each 10 ml of water sample that is tested. We compared the sensitivity and the specificity of our platform using multiple supervised classification models, including support vector machines and nearest neighbors, and demonstrated that a bootstrap aggregating (i.e. bagging approach using raw image file format provides the best performance for automated detection of Giardia cysts. We evaluated the performance of this machine learning enabled pathogen detection device with water samples taken from different sources (e.g. tap water, non-potable water, pond

  14. Comparison of supervised machine learning algorithms for waterborne pathogen detection using mobile phone fluorescence microscopy

    KAUST Repository

    Ceylan Koydemir, Hatice

    2017-06-14

    Giardia lamblia is a waterborne parasite that affects millions of people every year worldwide, causing a diarrheal illness known as giardiasis. Timely detection of the presence of the cysts of this parasite in drinking water is important to prevent the spread of the disease, especially in resource-limited settings. Here we provide extended experimental testing and evaluation of the performance and repeatability of a field-portable and cost-effective microscopy platform for automated detection and counting of Giardia cysts in water samples, including tap water, non-potable water, and pond water. This compact platform is based on our previous work, and is composed of a smartphone-based fluorescence microscope, a disposable sample processing cassette, and a custom-developed smartphone application. Our mobile phone microscope has a large field of view of ~0.8 cm2 and weighs only ~180 g, excluding the phone. A custom-developed smartphone application provides a user-friendly graphical interface, guiding the users to capture a fluorescence image of the sample filter membrane and analyze it automatically at our servers using an image processing algorithm and training data, consisting of >30,000 images of cysts and >100,000 images of other fluorescent particles that are captured, including, e.g. dust. The total time that it takes from sample preparation to automated cyst counting is less than an hour for each 10 ml of water sample that is tested. We compared the sensitivity and the specificity of our platform using multiple supervised classification models, including support vector machines and nearest neighbors, and demonstrated that a bootstrap aggregating (i.e. bagging) approach using raw image file format provides the best performance for automated detection of Giardia cysts. We evaluated the performance of this machine learning enabled pathogen detection device with water samples taken from different sources (e.g. tap water, non-potable water, pond water) and achieved

  15. Heavy rainfall and waterborne disease outbreaks: the Walkerton example.

    Science.gov (United States)

    Auld, Heather; MacIver, D; Klaassen, J

    Recent research indicates that excessive rainfall has been a significant contributor to historical waterborne disease outbreaks. The Meteorological Service of Canada, Environment Canada, provided an analysis and testimony to the Walkerton Inquiry on the excessive rainfall events, including an assessment of the historical significance and expected return periods of the rainfall amounts. While the onset of the majority of the Walkerton, Ontario, Escherichia coli O157:H7 and Campylobacter outbreak occurred several days after a heavy rainfall on May 12, the accumulated 5-d rainfall amounts from 8-12 May were particularly significant. These 5-d accumulations could, on average, only be expected once every 60 yr or more in Walkerton and once every 100 yr or so in the heaviest rainfall area to the south of Walkerton. The significant link between excess rainfall and waterborne disease outbreaks, in conjunction with other multiple risk factors, indicates that meteorological and climatological conditions need to be considered by water managers, public health officials, and private citizens as a significant risk factor for water contamination. A system to identify and project the impacts of such challenging or extreme weather conditions on water supply systems could be developed using a combination of weather/climate monitoring information and weather prediction or quantitative precipitation forecast information. The use of weather monitoring and forecast information or a "wellhead alert system" could alert water system and water supply managers on the potential response of their systems to challenging weather conditions and additional requirements to protect health. Similar approaches have recently been used by beach managers in parts of the United States to predict day-to-day water quality for beach advisories.

  16. Study on Synthesis and Properties of Flame-retardant Waterborne Polyurethanes%阻燃水性聚氨酯的合成与性能研究

    Institute of Scientific and Technical Information of China (English)

    宋海香; 王艳飞; 张艳维; 王猛

    2016-01-01

    oxygen index has reached 36%when the flame retardant additives is 10%, al⁃so reached the non-combustible level. Flame-retardant performance and stability of IPDI type flame-retardant waterborne polyurethane is superior to TDI type flame-retardant WPU, particle size and Zeta potential test showed that particle size and stability of the two kinds of WPU has little change after addition of flame retardant.

  17. Excel file of salivary antibody analysis for Boqueron Beach study, Puerto Rico for six waterborne pathogens.

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset is the raw Luminex antibody responses to six common waterborne pathogens reported in MFI (Median Fluorescence Intensity) units. This dataset is...

  18. Quantifying the impact of climate change on enteric waterborne pathogen concentrations in surface water

    NARCIS (Netherlands)

    Hofstra, N.

    2011-01-01

    Climate change, among other factors, will impact waterborne pathogen concentrations in surface water worldwide, possibly increasing the risk of diseases caused by these pathogens. So far, the impacts are only determined qualitatively and thorough quantitative estimates of future pathogen concentrati

  19. Multiplex PCR detection of waterborne intestinal protozoa: microsporidia, Cyclospora, and Cryptosporidium.

    Science.gov (United States)

    Lee, Seung-Hyun; Joung, Migyo; Yoon, Sejoung; Choi, Kyoungjin; Park, Woo-Yoon; Yu, Jae-Ran

    2010-12-01

    Recently, emerging waterborne protozoa, such as microsporidia, Cyclospora, and Cryptosporidium, have become a challenge to human health worldwide. Rapid, simple, and economical detection methods for these major waterborne protozoa in environmental and clinical samples are necessary to control infection and improve public health. In the present study, we developed a multiplex PCR test that is able to detect all these 3 major waterborne protozoa at the same time. Detection limits of the multiplex PCR method ranged from 10(1) to 10(2) oocysts or spores. The primers for microsporidia or Cryptosporidium used in this study can detect both Enterocytozoon bieneusi and Encephalitozoon intestinalis, or both Cryptosporidium hominis and Cryptosporidium parvum, respectively. Restriction enzyme digestion of PCR products with BsaBI or BsiEI makes it possible to distinguish the 2 species of microsporidia or Cryptosporidium, respectively. This simple, rapid, and cost-effective multiplex PCR method will be useful for detecting outbreaks or sporadic cases of waterborne protozoa infections.

  20. Surveillance for Waterborne Disease Outbreaks Associated with Drinking Water United States, 2007-2008

    Science.gov (United States)

    Problem/Condition: Since 1971, the Centers for Disease Control and Prevention (CDC), the U.S. Environmental Protection Agency (EPA), and the Council of State and Territorial Epidemiologists have maintained a collaborative Waterborne Disease and Outbreak Surveillance System (WBDOS...

  1. Development of saliva-based exposure assays for detecting exposure to waterborne pathogens

    Science.gov (United States)

    Identifying which pathogens we are exposed to can be challenging because many types of pathogens can be found in water and many pathogens have similar symptoms. EPA scientists have developed a simple way to measure human exposure to waterborne pathogens.

  2. Detection of water-borne E. coli O157 using the integrating waveguide biosensor☆

    OpenAIRE

    Zhu, Peixuan; Shelton, Daniel R.; Karns, Jeffrey S.; Sundaram, Appavu; Li, Shuhong; Amstutz, Pete; Tang, Cha-Mei

    2005-01-01

    Escherichia coli O157:H7, the most common serotype of enterohemorrhagic E. coli (EHEC), is responsible for numerous food-borne and water-borne infections worldwide. An integrating waveguide biosensor is described for the detection of water-borne E. coli O157, based on a fluorescent sandwich immunoassay performed inside a glass capillary waveguide. The genomic DNA of captured E. coli O157 cells was extracted and quantitative real-time PCR subsequently performed to assess biosensor-capture effi...

  3. Feeding reduces waterborne Cu bioaccumulation in a marine rabbitfish Siganus oramin.

    Science.gov (United States)

    Guo, Zhiqiang; Zhang, Wei; Du, Sen; Zhou, Yanyan; Gao, Na; Zhang, Li; Green, Iain

    2016-01-01

    Waterborne metal uptake has been extensively studied and dietary metal assimilation is increasingly recognized in fish, whilst the interaction between the two uptake routes is largely overlooked. This study compared the waterborne Cu bioaccumulation ((65)Cu as tracer) in a juvenile rabbitfish at different feeding regimes (starvation (SG), feeding normal diet (NDG) or diet supplemented with extra Cu (DCG)) to test the hypothesis that feeding can influence waterborne metal uptake in marine fish. NDG and DCG diet was fed as a single meal and then all fish were exposed to waterborne (65)Cu for 48 h, during which the time course sampling was conducted to determine (65)Cu bioaccumulation, chyme flow and dietary Cu assimilation. The results revealed that SG fish accumulated the highest (65)Cu, followed by NDG (61% of SG), whilst DCG fish accumulated the lowest (65)Cu (34% of SG). These results suggested a protective effect of feeding against waterborne Cu bioaccumulation. This effect was most notable between 10 min and 16 h when there was chyme in gastrointestinal tract (GT). Dietary Cu assimilation mainly occurred before 16 h after feeding. Waterborne (65)Cu influx rate in the GT was positively correlated with (65)Cu contents of chyme in NDG, whereas it was largely negatively correlated with (65)Cu contents of chyme in DCG. The waterborne Cu uptake in the GT was mainly influenced by the chyme flow and dietary Cu assimilation. Overall, our findings suggested that feeding has an important effect on waterborne metal uptake and that both the feeding status of the fish and the relative metal exposure through water and food should be considered in prediction of the metal bioaccumulation and biomonitoring programs.

  4. Waterborne Polyurethane-Polyacrylic Ester Hybrid Dispersion Modified by Hexamethylene Diisocyanate Trimer%Waterborne Polyurethane-Polyacrylic Ester Hybrid Dispersion Modified by Hexamethylene Diisocyanate Trimer

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A self-emulsifying waterborne polyurethane dispersion was synthesized with both hexamethylene diisocyanate (HDI) trimer and toluene diisoeyanate (TDI), polyether diols N220, 1,4- butanediol(BDO), 2-hydroxymethyl-propionic acid(DMPA) and epoxy resin E-20 as main raw materials with acetone-based method. The dispersion was further modified by methyl methacrylate (MMA) to form a kind of nuclear-shell hybrid dispersion, in which the hydrophobic nuclear was the polymethyl methacrylate and the hydrophilic shell was the self-emulsifying waterborne polyurethane dispersion modified by HDI trimer.

  5. Comparison of internal process control viruses for detection of food and waterborne viruses.

    Science.gov (United States)

    Blanco Fernández, María Dolores; Barrios, Melina Elizabeth; Cammarata, Robertina Viviana; Torres, Carolina; Taboga, Oscar Alberto; Mbayed, Viviana Andrea

    2017-03-29

    Enteric viruses are pathogens associated with food- and waterborne outbreaks. The recovery of viruses from food or water samples is affected by the procedures applied to detect and concentrate them. The incorporation of an internal process control virus to the analyses allows monitoring the performance of the methodology. The aim of this study was to produce a recombinant adenovirus (rAdV) and apply it together with bacteriophage PP7 as process controls. The rAdV carries a DNA construction in its genome to differentiate it from wild-type adenovirus by qPCR. The stability of both control viruses was evaluated at different pH conditions. The rAdV was stable at pH 3, 7, and 10 for 18 h. PP7 infectious particles were stable at pH 7 and showed a 2.14 log reduction at pH 10 and total decay at pH 3 after 18 h. Three virus concentration methods were evaluated: hollow-fiber tap water ultrafiltration, wastewater ultracentrifugation, and elution-PEG precipitation from lettuce. Total and infectious viruses were quantified and their recoveries were calculated. Virus recovery for rAdV and PP7 by ultrafiltration showed a wide range (2.10-84.42 and 13.54-84.62%, respectively), whereas that by ultracentrifugation was 5.05-13.71 and 6.98-13.27%, respectively. The performance of ultracentrifugation to concentrate norovirus and enteroviruses present in sewage was not significantly different to the recovery of control viruses. For detection of viruses from lettuce, genomic copies of PP7 were significantly more highly recovered than adenovirus (14.74-18.82 and 0.00-3.44%, respectively). The recovery of infectious virus particles was significantly affected during sewage ultracentrifugation and concentration from lettuce. The simultaneous use of virus controls with dissimilar characteristics and behaviors might resemble different enteric viruses.

  6. Click Cross-Linking-Improved Waterborne Polymers for Environment-Friendly Coatings and Adhesives.

    Science.gov (United States)

    Hu, Jianqing; Peng, Kaimei; Guo, Jinshan; Shan, Dingying; Kim, Gloria B; Li, Qiyao; Gerhard, Ethan; Zhu, Liang; Tu, Weiping; Lv, Weizhong; Hickner, Michael A; Yang, Jian

    2016-07-13

    Waterborne polymers, including waterborne polyurethanes (WPU), polyester dispersions (PED), and polyacrylate emulsions (PAE), are employed as environmentally friendly water-based coatings and adhesives. An efficient, fast, stable, and safe cross-linking strategy is always desirable to impart waterborne polymers with improved mechanical properties and water/solvent/thermal and abrasion resistance. For the first time, click chemistry was introduced into waterborne polymer systems as a cross-linking strategy. Click cross-linking rendered waterborne polymer films with significantly improved tensile strength, hardness, adhesion strength, and water/solvent resistance compared to traditional waterborne polymer films. For example, click cross-linked WPU (WPU-click) has dramatically improved the mechanical strength (tensile strength increased from 0.43 to 6.47 MPa, and Young's modulus increased from 3 to 40 MPa), hardness (increased from 59 to 73.1 MPa), and water resistance (water absorption percentage dropped from 200% to less than 20%); click cross-linked PED (PED-click) film also possessed more than 3 times higher tensile strength (∼28 MPa) than that of normal PED (∼8 MPa). The adhesion strength of click cross-linked PAE (PAE-click) to polypropylene (PP) was also improved (from 3 to 5.5 MPa). In addition, extra click groups can be preserved after click cross-linking for further functionalization of the waterborne polymeric coatings/adhesives. In this work, we have demonstrated that click modification could serve as a convenient and powerful approach to significantly improve the performance of a variety of traditional coatings and adhesives.

  7. Identifiability and estimation of multiple transmission pathways in cholera and waterborne disease.

    Science.gov (United States)

    Eisenberg, Marisa C; Robertson, Suzanne L; Tien, Joseph H

    2013-05-07

    Cholera and many waterborne diseases exhibit multiple characteristic timescales or pathways of infection, which can be modeled as direct and indirect transmission. A major public health issue for waterborne diseases involves understanding the modes of transmission in order to improve control and prevention strategies. An important epidemiological question is: given data for an outbreak, can we determine the role and relative importance of direct vs. environmental/waterborne routes of transmission? We examine whether parameters for a differential equation model of waterborne disease transmission dynamics can be identified, both in the ideal setting of noise-free data (structural identifiability) and in the more realistic setting in the presence of noise (practical identifiability). We used a differential algebra approach together with several numerical approaches, with a particular emphasis on identifiability of the transmission rates. To examine these issues in a practical public health context, we apply the model to a recent cholera outbreak in Angola (2006). Our results show that the model parameters-including both water and person-to-person transmission routes-are globally structurally identifiable, although they become unidentifiable when the environmental transmission timescale is fast. Even for water dynamics within the identifiable range, when noisy data are considered, only a combination of the water transmission parameters can practically be estimated. This makes the waterborne transmission parameters difficult to estimate, leading to inaccurate estimates of important epidemiological parameters such as the basic reproduction number (R0). However, measurements of pathogen persistence time in environmental water sources or measurements of pathogen concentration in the water can improve model identifiability and allow for more accurate estimation of waterborne transmission pathway parameters as well as R0. Parameter estimates for the Angola outbreak suggest

  8. Soybean-oil-based waterborne polyurethane dispersions: effects of polyol functionality and hard segment content on properties.

    Science.gov (United States)

    Lu, Yongshang; Larock, Richard C

    2008-11-01

    The environmentally friendly vegetable-oil-based waterborne polyurethane dispersions with very promising properties have been successfully synthesized without difficulty from a series of methoxylated soybean oil polyols (MSOLs) with different hydroxyl functionalities ranging from 2.4 to as high as 4.0. The resulting soybean-oil-based waterborne polyurethane (SPU) dispersions exhibit a uniform particle size, which increases from about 12 to 130 nm diameter with an increase in the OH functionality of the MSOL from 2.4 to 4.0 and decreases with increasing content of the hard segments. The structure and thermophysical and mechanical properties of the resulting SPU films, which contain 50-60 wt % MSOL as renewable resources, have been studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, transmission electron microscopy, and mechanical testing. The experimental results reveal that the functionality of the MSOLs and the hard segment content play a key role in controlling the structure and the thermophysical and mechanical properties of the SPU films. These novel films exhibit tensile stress-strain behavior ranging from elastomeric polymers to rigid plastics and possess Young's moduli ranging from 8 to 720 MPa, ultimate tensile strengths ranging from 4.2 to 21.5 MPa, and percent elongation at break values ranging from 16 to 280%. This work has addressed concerns regarding gelation and higher cross-linking caused by the high functionality of vegetable-oil-based polyols. This article reports novel environmentally friendly biobased SPU materials with promising applications as decorative and protective coatings.

  9. Flow-through immunomagnetic separation system for waterborne pathogen isolation and detection: Application to Giardia and Cryptosporidium cell isolation

    Energy Technology Data Exchange (ETDEWEB)

    Ramadan, Qasem, E-mail: qasem.alramadan@epfl.ch [Bioelectronics Program, Institute of Microelectronics, 11 Science Park Road, Singapore 117685 (Singapore); Christophe, Lay; Teo, William; ShuJun, Li; Hua, Feng Han [Bioelectronics Program, Institute of Microelectronics, 11 Science Park Road, Singapore 117685 (Singapore)

    2010-07-12

    Simultaneous sample washing and concentration of two waterborne pathogen samples were demonstrated using a rotational magnetic system under continuous flow conditions. The rotation of periodically arranged small permanent magnets close to a fluidic channel carrying magnetic particle suspension allows the trapping and release of particles along the fluidic channel in a periodic manner. Each trapping and release event resembles one washing cycle. The performance of the magnetic separation system (MSS) was evaluated in order to test its functionality to isolate magnetic-labelled protozoan cells from filtered, concentrated tap water, secondary effluent water, and purified water. Experimental protocols described in US Environmental Protection Agency method 1623 which rely on the use of a magnetic particle concentrator, were applied to test and compare our continuous flow cell separation system to the standard magnetic bead-based isolation instruments. The recovery efficiencies for Giardia cysts using the magnetic tube holder and our magnetic separation system were 90.5% and 90.1%, respectively, from a tap water matrix and about 31% and 18.5%, respectively, from a spiked secondary effluent matrix. The recovery efficiencies for Cryptosporidium cells using the magnetic tube holder and our magnetic separation system were 90% and 83.3%, respectively, from a tap water matrix and about 38% and 36%, respectively, from a spiked secondary effluent matrix. Recoveries from all matrices with the continuous flow system were typically higher in glass tubing conduits than in molded plastic conduits.

  10. Development in investigating waterborne curing agents for epoxy resins and their modification technology%水性环氧固化剂改性技术研究进展

    Institute of Scientific and Technical Information of China (English)

    朱桐瑶; 马立群; 汪建新; 刘洪成; 李艳东

    2012-01-01

    概述了水性环氧固化剂的改性原理,介绍了Ⅰ型和Ⅱ型水性环氧固化剂的国内外发展概况、制备方法及发展趋势,其中包括水性聚氨酯改性、有机硅改性及无机纳米粒子改性水性固化剂和含磷水性固化剂.%The modification mechanism of waterbone epoxy curing agents was summarized.The development situation,preparation methods and development direction of I and Ⅱ types of waterborne epoxy curing agents modified with water-borne polyurethane,organic silicone or inorganic nano particles and containing phosphorus were introduced.

  11. Detection, Diversity, and Population Dynamics of Waterborne Phytophthora ramorum Populations.

    Science.gov (United States)

    Eyre, C A; Garbelotto, M

    2015-01-01

    Sudden oak death, the tree disease caused by Phytophthora ramorum, has significant environmental and economic impacts on natural forests on the U.S. west coast, plantations in the United Kingdom, and in the worldwide nursery trade. Stream baiting is vital for monitoring and early detection of the pathogen in high-risk areas and is performed routinely; however, little is known about the nature of water-borne P. ramorum populations. Two drainages in an infested California forest were monitored intensively using stream-baiting for 2 years between 2009 and 2011. Pathogen presence was determined both by isolation and polymerase chain reaction (PCR) from symptomatic bait leaves. Isolates were analyzed using simple sequence repeats to study population dynamics and genetic structure through time. Isolation was successful primarily only during spring conditions, while PCR extended the period of pathogen detection to most of the year. Water populations were extremely diverse, and changed between seasons and years. A few abundant genotypes dominated the water during conditions considered optimal for aerial populations, and matched those dominant in aerial populations. Temporal patterns of genotypic diversification and evenness were identical among aerial, soil, and water populations, indicating that all three substrates are part of the same epidemiological cycle, strongly influenced by rainfall and sporulation on leaves. However, there was structuring between substrates, likely arising due to reduced selection pressure in the water. Additionally, water populations showed wholesale mixing of genotypes without the evident spatial autocorrelation present in leaf and soil populations.

  12. Soybean oil-isosorbide-based waterborne polyurethane-urea dispersions.

    Science.gov (United States)

    Xia, Ying; Larock, Richard C

    2011-03-21

    A series of soybean oil-based amide diol-isosorbide waterborne polyurethane-urea (PUU) dispersions have been successfully prepared, with amounts of isosorbide ranging from 0 to 20 wt % of the total diol content. The thermal and mechanical properties of the resulting PUU films have been characterized by dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, and mechanical testing. The results reveal that the glass transition temperature is increased with increased amounts of isosorbide, and the mechanical properties are improved significantly with the incorporation of isosorbide. For example, the Young's modulus increases from 2.3 to 63 MPa and the ultimate tensile strength increases from 0.7 to 8.2 MPa when the isosorbide amount is increased from 0 to 20 wt %. The thermal stability decreases slightly with the incorporation of isosorbide. This work provides a new way of utilizing biorenewable materials, such as isosorbide and a soybean oil-based amide diol, for the preparation of high-performance polyurethane-urea coatings.

  13. Hepatitis E Virus: Foodborne, Waterborne and Zoonotic Transmission

    Directory of Open Access Journals (Sweden)

    Xiang-Jin Meng

    2013-09-01

    Full Text Available Hepatitis E virus (HEV is responsible for epidemics and endemics of acute hepatitis in humans, mainly through waterborne, foodborne, and zoonotic transmission routes. HEV is a single-stranded, positive-sense RNA virus classified in the family Hepeviridae and encompasses four known Genotypes (1–4, at least two new putative genotypes of mammalian HEV, and one floating genus of avian HEV. Genotypes 1 and 2 HEVs only affect humans, while Genotypes 3 and 4 are zoonotic and responsible for sporadic and autochthonous infections in both humans and several other animal species worldwide. HEV has an ever-expanding host range and has been identified in numerous animal species. Swine serve as a reservoir species for HEV transmission to humans; however, it is likely that other animal species may also act as reservoirs. HEV poses an important public health concern with cases of the disease definitively linked to handling of infected pigs, consumption of raw and undercooked animal meats, and animal manure contamination of drinking or irrigation water. Infectious HEV has been identified in numerous sources of concern including animal feces, sewage water, inadequately-treated water, contaminated shellfish and produce, as well as animal meats. Many aspects of HEV pathogenesis, replication, and immunological responses remain unknown, as HEV is an extremely understudied but important human pathogen. This article reviews the current understanding of HEV transmission routes with emphasis on food and environmental sources and the prevalence of HEV in animal species with zoonotic potential in humans.

  14. Engineering waterborne Pseudomonas aeruginosa out of a critical care unit.

    Science.gov (United States)

    Garvey, Mark I; Bradley, Craig W; Wilkinson, Martyn A C; Bradley, Christina; Holden, Elisabeth

    2017-08-01

    To describe engineering and holistic interventions on water outlets contaminated with Pseudomonas aeruginosa and the observed impact on clinical P. aeruginosa patient isolates in a large Intensive Care Unit (ICU). Descriptive study. Queen Elizabeth Hospital Birmingham (QEHB), part of University Hospitals Birmingham (UHB) NHS Foundation Trust is a tertiary referral teaching hospital in Birmingham, UK and provides clinical services to nearly 1 million patients every year. Breakpoint models were used to detect any significant changes in the cumulative yearly rates of clinical P. aeruginosa patient isolates from August 2013-December 2016 across QEHB. Water sampling undertaken on the ICU indicated 30% of the outlets were positive for P. aeruginosa at any one time. Molecular typing of patient and water isolates via Pulsed Field Gel Electrophoresis suggested there was a 30% transmission rate of P. aeruginosa from the water to patients on the ICU. From, February 2014, QEHB implemented engineering interventions, consisting of new tap outlets and PALL point-of-use filters; as well as holistic measures, from February 2016 including a revised tap cleaning method and appropriate disposal of patient waste water. Breakpoint models indicated the engineering and holistic interventions resulted in a significant (p<0.001) 50% reduction in the number of P. aeruginosa clinical patient isolates over a year. Here we demonstrate that the role of waterborne transmission of P. aeruginosa in an ICU cannot be overlooked. We suggest both holistic and environmental factors are important in reducing transmission. Copyright © 2017 Elsevier GmbH. All rights reserved.

  15. Bio-control of waterborne pathogens using Lactobacillus spp.

    Science.gov (United States)

    Gaikwad, Ghyandeep L; Gupta, Prateksha; Wate, Satish R

    2012-11-01

    Bacteria play a significant role in water contamination. Chemicals are mostly used for the treatment of bacteriologically contaminated water. The use of bacterial interactions is a new approach to limit the pathogens' growth. Detection of antimicrobial substances produced by lactic acid bacteria against the waterborne pathogens is the objective of this work. Microbiological and biochemical methods were used to identify lactic acid bacteria having an antimicrobial activity. Evaluation of antimicrobial activity with growth kinetic measurements was performed. Four isolates of lactic acid bacteria obtained from whey and curd were identified. The predominant species belonging to the Lactobacillus genera are: Lactobacillus rhamnosus, Lactobacillus sakei, Lactobacillus paracasei, and Lactobacillus paraplantarum. The present study revealed that the Lactobacillus consortium is able to inhibit Staphylococcus aureus's growth along with Escherichia coli and Vibrio species. In mixed culture, after 24 h, the Lactobacillus consortium reduces the growth of S. aureus by 2.03 log; moreover, the growth of the latter bacteria totally ceased after 72 h of incubation. The protein produced by the Lactobacillus consortium was responsible for arresting the growth of S. aureus.

  16. 阴离子型水性聚氨酯和阳离子型水性聚氨酯的合成及分析%Preparations and Analysis of Cationic and Anionic Waterborne Polyurethane

    Institute of Scientific and Technical Information of China (English)

    张伟; 邢凤荣; 李雪

    2012-01-01

    以甲苯二异氰酸酯(TDI)和聚酯二醇等为基本原料,在NCO/OH比例及反应物量相同的情况下,分别合成了阴离子型水性聚氨酯和阳离子型水性聚氨酯。对它们进行了红外光谱分析、热重分析、粒径分析、吸水率测定和力学测试。结果表明:合成的阴离子水性聚氨酯无残余的-NCO,粒径、吸水率小于阳离子型水性聚氨酯,拉伸强度、断裂伸长率大于阳离子型水性聚氨酯,耐水性强于阳离子型水性聚氨酯。%Anionic and cationic waterborne polyurethane were synthesized by using the same amount of toluene diisocyanate and polyester glycol as raw materials under the same mole ratio of NCO/OH. These two waterborne polyurethanes were characterized by FTIR, TGA, particle size analysis, water absorption rate test and mechanical properties test. The results showed that there was no residual --NCO in anionic waterborne polyurethane, and it had smaller particle size, lower water absorption rate, larger tensile strength, larger breaking elongation, and bet- ter water resistance than cationic waterborne polyurethane.

  17. Toxicity and bioaccumulation of waterborne and dietary selenium in juvenile bluegill (Lepomis macrochirus)

    Science.gov (United States)

    Cleveland, Laverne; Little, Edward E.; Buckler, Denny R.; Wiedmeyer, Raymond H.

    1993-01-01

    Juvenile bluegill (Lepomis macrochirus) were exposed to waterborne selenium as a 6:1 mixture of selenate to selenite (as Se) for 60 d and to dietary seleno-l-methionine for 90 d. Measured concentrations of total selenium in the waterborne exposure ranged from 0.16 to 2.8 mg/l, and concentrations of seleno-l-methionine in the test diet ranged from 2.3 to 25.0 mg/kg wet weight. Mortality, body weight, condition factor, swimming and feeding behavior, aggression, and selenium tissue residues were monitored during the tests. Increased mortality at measured concentrations of 0.64 mg Se/l and greater was the primary adverse effect of waterborne selenium on the juvenile bluegill. Bluegill exposed to 2.8 mg/l of waterborne Se for 30 d exhibited a significant reduction in condition factor (K), whereas dietary exposure of bluegill to 25 mg Se/kg for 30 d and 13 mg Se/kg or greater for 90 d elicited significant reductions in K. Mortality and swimming activity of bluegill were not affected in the dietary exposure. Net accumulation of Se from both water and diet was directly related to exposure concentration. Bioconcentration factors ranged from 5 to 7 for bluegill exposed to waterborne Se and from 0.5 to 1.0 for fish exposed to dietary Se. Results of these laboratory tests indicate that survival of bluegill may be impaired in natural waters with elevated Se concentrations.

  18. Synthesis of waterborne polyurethane containing alkoxysilane side groups and the properties of the hybrid coating films

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qi; Guo, Longhai [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Qiu, Teng, E-mail: qiuteng@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Xiao, Weidong; Du, Dianxing [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Xiaoyu, E-mail: lixy@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China)

    2016-07-30

    Highlights: • A diol with side-chain trimethoxysilane (DEA-Si) was synthesized using 3-(methacryloxypropyl)trimethoxysilane (MAPTS) and diethanolamine (DEA). • The crosslinking structure could in situ formed within the WPU matrix through sol-gel process. • The Si tends to shift to the polymer-air interface due to the flexible long alkyl-ester side chain. • The incorporation of DEA-Si enhanced mechanical and surface hydrophobic properties of WPU films. - Abstract: A series of waterborne polyurethane (WPU) containing alkoxysilane side groups were synthesized by using the dihydroxy functionalized alkoxysilane. The diol with trimethoxysilane groups at the side chains was synthesized via Michael addition between 3-(methacryloxypropyl)trimethoxysilane (MAPTS) and diethanolamine (DEA). The silane diol was applied as the chain extender for the NCO-endcapped prepolymer of isophorone diisocyanate, polycarbonate diol, 2,2-bis(hydroxymethyl) butyric acid and 1,4-butanediol. The products with the silane content varied from 1.2 to 16.5 wt% were dispersed in water after neutralization. The effect of the silane diol on the particle size and morphology of the WPU dispersion was studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. X-ray photoelectron spectroscopy (XPS) characterization was carried out on the coating film of the WPU, revealing that the long flexible side chain is favorable for the silane components to emigrate toward the film surface and crosslink during the film formation process. As a result, both the surface contact angle to water and water adsorption of the WPU coating films increased with the silane content. Furthermore, the mechanical properties including the modulus and tensile strength of the films were also improved by the incorporation of silane diol.

  19. Preparation and Its Performance of Waterborne Automobile Metallic Primer%水性汽车金属闪光底色漆的制备及性能

    Institute of Scientific and Technical Information of China (English)

    王淑娟; 汤汉良; 罗晖

    2011-01-01

    采用核壳结构的丙烯酸乳液作为成膜树脂,与非浮型水性铝粉颜料、各种涂料助剂等制备出一种汽车涂料用的水性金属闪光底色漆,介绍了水性金属闪光漆的配方及各项技术指标,讨论了成膜树脂、铝粉、助剂、成膜助剂及施工工艺的选择。结果表明,将核壳结构的丙烯酸乳液引入金属闪光体系,可以有效地减少金属漆中粒子的沉降,提高了体系的稳定性和各项涂膜性能。本项目研制的水性汽车金属闪光漆能满足合同规定的指标要求,而且具有良好的施工性能。%The waterborne metallic coating which can be used on automobile was prepared by using hydroxyl acrylic composite dispersion as film-former,non-floating-type waterborne aluminum powder and additives.The selections of resin,waterborne aluminum powder,additives,coalescent and construction technology were discussed.The results show that the introduction of acrylate emulsion with core/shell structure into coatings can reduce the particle sedimentation and improve the stability and performance of the coatings.The metallic coatings with good workability and it can meet to the demands described in contract.

  20. Surveillance for waterborne disease and outbreaks associated with recreational water use and other aquatic facility-associated health events-United States, 2005-2006

    Science.gov (United States)

    PROBLEM/CONDITION: Since 1971, CDC, the U.S. Environmental Protection Agency, and the Council of State and Territorial Epidemiologists have collaboratively maintained the Waterborne Disease and Outbreak Surveillance System for collecting and reporting data related to waterborne-d...

  1. Effects of wastewater disinfection on waterborne bacteria and viruses

    Science.gov (United States)

    Blatchley, E. R.; Gong, W.-L.; Alleman, J.E.; Rose, J.B.; Huffman, D.E.; Otaki, M.; Lisle, J.T.

    2007-01-01

    Wastewater disinfection is practiced with the goal of reducing risks of human exposure to pathogenic microorganisms. In most circumstances, the efficacy of a wastewater disinfection process is regulated and monitored based on measurements of the responses of indicator bacteria. However, inactivation of indicator bacteria does not guarantee an acceptable degree of inactivation among other waterborne microorganisms (e.g., microbial pathogens). Undisinfected effluent samples from several municipal wastewater treatment facilities were collected for analysis. Facilities were selected to provide a broad spectrum of effluent quality, particularly as related to nitrogenous compounds. Samples were subjected to bench-scale chlorination and dechlorination and UV irradiation under conditions that allowed compliance with relevant discharge regulations and such that disinfectant exposures could be accurately quantified. Disinfected samples were subjected to a battery of assays to assess the immediate and long-term effects of wastewater disinfection on waterborne bacteria and viruses. In general, (viable) bacterial populations showed an immediate decline as a result of disinfectant exposure; however, incubation of disinfected samples under conditions that were designed to mimic the conditions in a receiving stream resulted in substantial recovery of the total bacterial community. The bacterial groups that are commonly used as indicators do not provide an accurate representation of the response of the bacterial community to disinfectant exposure and subsequent recovery in the environment. UV irradiation and chlorination/dechlorination both accomplished measurable inactivation of indigenous phage; however, the extent of inactivation was fairly modest under the conditions of disinfection used in this study. UV irradiation was consistently more effective as a virucide than chlorination/dechlorination under the conditions of application, based on measurements of virus (phage

  2. Waterborne transmission of protozoan parasites: Review of worldwide outbreaks - An update 2011-2016.

    Science.gov (United States)

    Efstratiou, Artemis; Ongerth, Jerry E; Karanis, Panagiotis

    2017-01-25

    This review provides a comprehensive update of worldwide waterborne parasitic protozoan outbreaks that occurred with reports published since previous reviews largely between January 2011 and December 2016. At least 381 outbreaks attributed to waterborne transmission of parasitic protozoa were documented during this time period. The nearly half (49%) of reports occurred in New Zealand, 41% of the outbreaks in North America and 9% in Europe. The most common etiological agent was Cryptosporidium spp., reported in 63% (239) of the outbreaks, while Giardia spp. was mentioned in 37% (142). No outbreaks attributed to other parasitic protozoa were reported. The distribution of reported outbreaks does not correspond to more broadly available epidemiological data or general knowledge of water and environmental conditions in the reporting countries. Noticeably, developing countries that are probably most affected by such waterborne disease outbreaks still lack reliable surveillance systems, and an international standardization of surveillance and reporting systems has yet to be established.

  3. Synthesis and Properties of Epoxy Resin Modified Waterborne Polyurethane Ink Vehicle%环氧树脂改性水性聚氨酯油墨连结料的合成与性能

    Institute of Scientific and Technical Information of China (English)

    杜娟

    2012-01-01

    以聚酯多元醇、甲苯二异氰酸酯和二羟甲基丙酸为主要原料,采用环氧树脂改性制备出稳定的水性聚氨酯油墨连结料.水性油墨连结料的红外光谱分析说明合成了水性聚氨酯结构油墨连结料;差示扫描量热法测试表明环氧树脂复合改性增加了涂膜交联度,涂膜玻璃化转变温度(Tg)明显提高;粒径分布分析说明经过环氧树脂改性水性聚氨酯树脂的粒径分布变宽;热失质量分析说明环氧树脂改性增加了涂膜的耐热性;水性聚氨酯油墨性能测试说明水性油墨连结料PUIV -1的基本性能优于所用的水性丙烯酸连结料.%A series of stable waterborne polyurethane ink vehicles have been prepared from toluene diiso-cyanate, polyester polyols and dimethylolpropionic acid and epoxy as modification resin. FT - IR analysis of waterborne polyurethane ink vehicle showed that waterborne polyurethane ink vehicle was prepared. Differential scanning calorimetric measurements of films tests showed that the crosslink degree and Tg of the films here improved greatly when epoxy resin was added. Particle size distribution analysis showed that waterborne polyurethane ink vehicle modified by epoxy resin was broaden. TG analysis showed that heat resistance of the films improved much when epoxy resin as modification agent. The properties test of waterborne polyurethane ink vehicle showed that PUIV -1 was better than waterborne acrylic vehicle.

  4. Animal Model Reveals Potential Waterborne Transmission of Helicobacter pylori Infection.

    Science.gov (United States)

    Boehnke, Kevin F; Eaton, Kathryn A; Valdivieso, Manuel; Baker, Laurence H; Xi, Chuanwu

    2015-10-01

    Helicobacter pylori infection has been consistently associated with lack of access to clean water and proper sanitation, but no studies have demonstrated that the transmission of H. pylori can occur from drinking contaminated water. In this study, we used a laboratory mouse model to test whether waterborne H. pylori could cause gastric infection. Groups of immunocompetent C57/BL6 Helicobacter-free mice were exposed to static concentrations (1.29 × 10(5), 10(6), 10(7), 10(8), and 10(9) CFU/L) of H. pylori in their drinking water for 4 weeks. One group of Helicobacter-free mice was exposed to uncontaminated water as a negative control. H. pylori morphology changes in water were examined using microscopy Live/Dead staining. Following exposure, H. pylori infection and inflammation status in the stomach were evaluated using quantitative culture, PCR, the rapid urease test, and histology. None of the mice in the negative control or 10(5) groups were infected. One of 20 cages (one of 40 mice) of the 10(6) group, three of 19 cages (four of 38 mice) of the 10(7) CFU/L group, 19 of 20 cages (33 of 40 mice) of the 10(8) group, and 20 of 20 cages (39 of 40 mice) of the 10(9) CFU/L group were infected. Infected mice had significantly higher gastric inflammation than uninfected mice (27.86% higher inflammation, p < .0001). We offer proof that H. pylori in water is infectious in mice, suggesting that humans drinking contaminated water may be at risk of contracting H. pylori infection. Much work needs to be performed to better understand the risk of infection from drinking H. pylori-contaminated water. © 2015 John Wiley & Sons Ltd.

  5. Effect of Nano Al Pigment on the Anticorrosive Performance of Waterborne Epoxy Coatings

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper presents the results regarding the effect of nano aluminum powder pigment concentration on the protective properties of waterborne epoxy films in 3.5 wt pct NaCl solution. The anticorrosive performance of the coatings with 0.5, 1, and 3 wt pct pigments and none pigment were investigated using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and Raman spectroscopy techniques.The results show that adding appropriate amount of nano-aluminium powder pigment can enhance the barrier properties of the epoxy coating, which is attributed to the surface effect of nanoparticles and the compatibility of the pigment with the waterborne epoxy coatings.

  6. 扩链剂对脂肪族水性聚氨酯性能的影响%Effect of Chain Extender on Properties of Aliphatic Waterborne Polyurethane

    Institute of Scientific and Technical Information of China (English)

    张红武; 倪忠斌; 陈明清; 刘士荣

    2012-01-01

    A series of waterborne polyurethane dispersions were synthesized from PPG. IPDI. DMPA and EDA by prepolymer dispersion method. The effects of DMPA content and the method of chain extension with EDA on the emulsion stability and particle size, the mechanical properties and the ratio of absorbent water for waterborne polyurethane film were studied. The results show that, good performance of polyurethane emulsion was gained under the conditions of the content of DMPA = 6%, and the method of chain extension of EDA soluble in water.%以异佛尔酮二异氰酸酯(IPDI)和聚酸二醇(PPG:Mn=1000)为原料进行预聚反应,二羟甲基丙酸(DMPA)为亲水扩链剂,按不同配比合成了水性聚氨酯,并就DMPA用量、乙二胺(EDA)扩链方式对水性聚氨酯乳液的稳定性、粒径、及其材料的力学性能、吸水率等的影响进行了研究。结果表明:DMPA用量6%左右,EDA溶于水中进行边扩链、边乳化的方法制得了综合性能较好的水性聚氨酯。

  7. Waterborne diseases classification and relationship with social-environmental factors in Florianópolis city - Southern Brazil.

    Science.gov (United States)

    Cesa, M; Fongaro, G; Barardi, C R M

    2016-04-01

    This study aimed to investigate and classify the occurrence of waterborne diseases in Florianópolis city, Santa Catarina State, Southern Brazil and to correlate these diseases with the following social-environmental indicators of the local population: type of water supply, adequate collection and sewage treatment, areas of flooding and domestic water tank cleaning. Reports of outpatients were analyzed for surveillance of waterborne diseases during the period of 2002 to 2009. Waterborne diseases were classified into four groups: Group A: diarrheal diseases; Group B: parasitological diseases; Group C: skin diseases and Group D: eye diseases. The diarrheal, parasitological and skin diseases were the most frequently reported. Waterborne diseases belonging to Group A in all sites were correlated with other waterborne diseases groups, which can be an indicator of the circulation of other waterborne diseases. Regarding the social-environmental indicators assessed, the most correlated with waterborne diseases were the origin and quality of the water supply, followed by inadequate collection and treatment of sewage, frequent flooding, and finally the lack of cleanliness of the water reservoir. The results highlight the need for policies aiming for improvement of the sanitation service in the maintenance of human, animal and environmental health.

  8. Facile approach to fabricate waterborne polyaniline nanocomposites with environmental benignity and high physical properties

    Science.gov (United States)

    Wang, Haihua; Wen, Huan; Hu, Bin; Fei, Guiqiang; Shen, Yiding; Sun, Liyu; Yang, Dong

    2017-03-01

    Waterborne polyaniline (PANI) dispersion has got extensive attention due to its environmental friendliness and good processability, whereas the storage stability and mechanical property have been the challenge for the waterborne PANI composites. Here we prepare for waterborne PANI dispersion through the chemical graft polymerisation of PANI into epichlorohydrin modified poly (vinyl alcohol) (EPVA). In comparison with waterborne PANI dispersion prepared through physical blend and in situ polymerisation, the storage stability of PANI-g-EPVA dispersion is greatly improved and the dispersion keeps stable for one year. In addition, the as-prepared PANI-g-EPVA film displays more uniform and smooth morphology, as well as enhanced phase compatibility. PANI is homogeneously distributed in the EPVA matrix on the nanoscale. PANI-g-EPVA displays different morphology at different aniline content. The electrical conductivity corresponds to 7.3 S/cm when only 30% PANI is incorporated into the composites, and then increases up to 20.83 S/cm with further increase in the aniline content. Simultaneously, the tensile strength increases from 35 MPa to 64 MPa. The as-prepared PANI-g-EPVA dispersion can be directly used as the conductive ink or coatings for cellulose fibre paper to prepare flexible conductive paper with high conductivity and mechanical property, which is also suitable for large scalable production.

  9. Use of Pathogen-Specific Antibody Biomarkers to Estimate Waterborne Infections in Population-Based Settings

    Science.gov (United States)

    Purpose of reviewThis review discusses the utility of pathogen-specific antibody biomarkers for improving estimates of the population burden of waterborne infections, assessing the fraction of infections that can be prevented by specific water treatments, and understanding transm...

  10. Impact of food and water-borne diseases on European population health

    NARCIS (Netherlands)

    Cassini, A.; Colzani, E.; Kramarz, P.; Kretzschmar, M. E.; Takkinen, J.

    2016-01-01

    Composite health measures are increasingly applied in studies aiming at describing the burden of diseases, and food and water-borne diseases (FWDs) are no exception. The Burden of Communicable Diseases in Europe (BCoDE) is a project led and funded by the European Centre for Disease Prevention and Co

  11. Adhesion and viability of waterborne pathogens on p-DADMAC coatings

    NARCIS (Netherlands)

    van der Mei, Henny C.; Rustema-Abbing, Minie; Langworthy, Don E.; Collias, Dimitris I.; Mitchell, Michael D.; Bjorkquist, Dave W.; Busscher, Henk J.

    2008-01-01

    The attachment of waterborne pathogens onto surfaces can be increased by coating the surfaces with positive charge-enhancing polymers. In this paper, the increased efficacy of polydiallyldimethylammonium chloride (p-DADMAC) coatings on glass was evaluated in a parallel plate flow chamber with the us

  12. Impact of food and water-borne diseases on European population health

    NARCIS (Netherlands)

    Cassini, A.; Colzani, E.; Kramarz, P.; Kretzschmar, M. E.; Takkinen, J.

    2016-01-01

    Composite health measures are increasingly applied in studies aiming at describing the burden of diseases, and food and water-borne diseases (FWDs) are no exception. The Burden of Communicable Diseases in Europe (BCoDE) is a project led and funded by the European Centre for Disease Prevention and

  13. Waterborne toxoplasmosis investigated and analyzed under hydrogeological assessment: new data and perspectives for further research

    Science.gov (United States)

    We present a set of data on human and chicken Toxoplasma gondii seroprevalence that was investigated and analyzed in light of groundwater vulnerability information in an area of endemic waterborne toxoplasmosis in Brazil. Hydrogeological assessment was undertaken to conduct water collection from wel...

  14. SURVEILLANCE FOR WATERBORNE-DISEASE OUTBREAKS-UNITED STATES, 1997-1998

    Science.gov (United States)

    PROBLEM/CONDITION: Since 1971, CDC and the U.S. Environmental Protection Agency (EPA) have maintained a collaborative surveillance system for collecting and periodically reporting data relating to occurrences and causes of waterborne-disease outbreaks (WBDOs). REPORTING PERIOD CO...

  15. SURVEILLANCE FOR WATERBORNE-DISEASE OUTBREAKS - UNITED STATES, 1999-2000

    Science.gov (United States)

    PROBLEM/CONDITION: Since 1971, CDC, the U.S. Environmental Protection Agency (EPA), and the Council of State and Territorial Epidemiologists (CSTE) have maintained a collaborative surveillance system for the occurrences and causes of waterborne-disease outbreaks (WBDOs).This surv...

  16. Global Warming and Trans-Boundary Movement of Waterborne Microbial Pathogens - Book Chapter

    Science.gov (United States)

    Subtle increases in temperature can have profound impacts on the prevalence of various waterborne microbial pathogens. Such impacts may be seen in three major areas, 1) fecally contaminated drinking water, 2) fresh produce that has been irrigated or processed with contaminated wa...

  17. Detection of coalescing agents in water-borne latex emulsions using an environment sensitive fluorescent probe

    NARCIS (Netherlands)

    Raja, T.N.; Brouwer, A.M.; Biemans, K.; Nabuurs, T.; Tennebroek, R.

    2010-01-01

    In this paper we report the determination of partitioning of coalescing agents (organic co-solvents) in water-borne latex emulsions by means of a fluorescence method. An environment-sensitive fluorescent probe 1 was copolymerized via emulsion polymerization. The presence of organic co-solvents insid

  18. Gold tailings as a source of water-borne uranium contamination of ...

    African Journals Online (AJOL)

    driniev

    2004-04-02

    Apr 2, 2004 ... in the stream that, in turn, is influenced by geological features of the catchment, ... sediments, it reduces further water-borne distribution of the metals ...... dissolved Fe(II) as Fe(OH)3 - without bacteria - is only possible in.

  19. Reach specificity in sediment E. coli population turnover and interaction with waterborne populations.

    Science.gov (United States)

    Piorkowski, Gregory; Jamieson, Rob; Bezanson, Greg; Truelstrup Hansen, Lisbeth; Yost, Chris

    2014-10-15

    Sediment-borne Escherichia coli can elevate waterborne concentrations through sediment resuspension or hyporheic exchange. This study sought to correlate hydrological, sediment transport, and water quality variables with: (i) the temporal stability of sediment E. coli populations [concentrations, strain richness and similarity (Raup-Crick index)]; and (ii) the contribution of sediment E. coli to the water column as defined through a library-dependent microbial source tracking approach that matched waterborne E. coli isolates to sediment E. coli populations. Three monitoring locations differing in their hydrological characteristics and adjacent upland fecal sources (dairy operation, low-density residential, and tile-drained cultivated field) were investigated. Sediment E. coli population turnover was influenced by sediment transport at upstream, high-energy reaches, but not at the downstream low-energy reach. Sediment contributions to the water column averaged 13% and 18%, and fecal sources averaged 17% and 21% at the upstream sites adjacent to dairy operations and low-density residential areas, respectively. Waterborne E. coli at the downstream site had low matches to E. coli from reach sediments (1%), higher matches to the upstream sediments (27% and 12%), and an average of 14% matches to the tile drained field. The percentage of waterborne E. coli matching sediment-borne E. coli at each stream reach varied in correlations to hydrological and sediment transport variables, suggesting reach-specific differences in the role of sediment resuspension and hyporheic exchange on E. coli transport.

  20. Global Warming and Trans-Boundary Movement of Waterborne Microbial Pathogens - Book Chapter

    Science.gov (United States)

    Subtle increases in temperature can have profound impacts on the prevalence of various waterborne microbial pathogens. Such impacts may be seen in three major areas, 1) fecally contaminated drinking water, 2) fresh produce that has been irrigated or processed with contaminated wa...

  1. Detection and quantification of virulent Aeromonas hydrophila in channel catfish tissues following waterborne challenge

    Science.gov (United States)

    The aim of this study was to understand the pathogenesis of motile aeromonas septicemia caused by virulent A. hydrophila (vAh) in channel catfish, Ictalurus punctatus. Adipose fin clipped catfish were challenged with vAh using waterborne challenge method and the distribution of vAh in catfish tissue...

  2. The simultaneous uptake of dietary and waterborne Cd in gastrointestinal tracts of marine yellowstripe goby Mugilogobius chulae.

    Science.gov (United States)

    Guo, Zhiqiang; Gao, Na; Wu, Yun; Zhang, Li

    2017-04-01

    Aquatic animals under waterborne metal exposure are also very likely exposed to elevated dietary metals. This study quantified the simultaneous uptake of dietary and waterborne Cd in gastrointestinal tracts (GT) of marine yellowstripe goby using a dual stable isotope tracer method. The Cd spiked diet (10-100 μg g(-1), (111)Cd as tracers) were fed to the fish as a single meal, and then the fish were exposed to waterborne Cd (0-500 μg L(-1), (113)Cd as tracers) for 48 h, during which the time-course uptake of Cd in the stomach and intestine was determined. The findings revealed that the dietary Cd uptake mainly occurred within 12 h after feeding. The fish exposed to 500 μg L(-1) waterborne Cd showed significantly lower Cd assimilation efficiency (2.07%) than the control group (3.48%) at the dietary Cd of 100 μg g(-1). Moreover, during 4-12 h when there was chyme in the GT, the waterborne Cd uptake in the intestine was lowest but the stomach showed the highest waterborne Cd uptake rate. The uptake of dietary and waterborne Cd, and the relative importance of dietary vs waterborne Cd was positively correlated with the Cd concentration in the chyme. Overall, this research demonstrated that there was interaction between dietary and waterborne Cd uptake in the GT of marine fish. The simultaneous uptake of metal from two routes is far more complex than the situation of a single route of metal uptake, which should be evaluated in determining metal bioaccumulation and toxicity in both laboratory and field metal exposure scenario. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. New progress in modification of waterborne polyurethanes%水性聚氨酯改性研究新进展

    Institute of Scientific and Technical Information of China (English)

    鲁艳; 艾照全; 蔡婷; 徐华斌

    2015-01-01

    Due to the widespread use of waterborne polyurethanes, the waterborne polyurethanes were modified more and more. Reviewed in terms of the number of modification of waterborne polyurethanes, and introduced some new types of raw materials for modification in this paper.%由于水性聚氨酯的广泛使用,对于水性聚氨酯的改性研究也越来越多。从改性的次数方面对水性聚氨酯改性进行了综合评述,并介绍了一些新型的改性原料。

  4. Biomarkers of waterborne copper exposure in the guppy Poecilia vivipara acclimated to salt water

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Anderson Abel de Souza [Universidade Federal do Rio Grande, Programa de Pós-Graduação em Oceanografia Biológica, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Hoff, Mariana Leivas Müller [Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Klein, Roberta Daniele [Universidade Federal do Rio Grande, Programa de Pós-Graduação em Ciências Fisiológicas – Fisiologia Animal Comparada, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Cardozo, Janaina Goulart [Universidade Federal do Rio Grande, Instituto de Ciências Biológicas, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Giacomin, Marina Mussoi [Universidade Federal do Rio Grande, Programa de Pós-Graduação em Ciências Fisiológicas – Fisiologia Animal Comparada, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); Pinho, Grasiela Lopes Leães [Universidade Federal do Rio Grande, Instituto de Oceanografia, Av. Itália km 8, 96201-900 Rio Grande, Rio Grande do Sul (Brazil); and others

    2013-08-15

    Highlights: •Acute effects of waterborne copper were evaluated in the estuarine guppy Poecilia vivipara. •Fishes were acutely exposed to waterborne copper in salt water. •Waterborne copper affects the response of several biochemical and genetic endpoints. •Catalase, reactive oxygen species, antioxidant capacity and lipid peroxidation are responsive to copper exposure. •Copper exposure induces DNA damages in fish erythrocytes. -- Abstract: The responses of a large suite of biochemical and genetic parameters were evaluated in tissues (liver, gills, muscle and erythrocytes) of the estuarine guppy Poecilia vivipara exposed to waterborne copper in salt water (salinity 24 ppt). Activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione reductase, and glutathione S-transferase), metallothionein-like protein concentration, reactive oxygen species (ROS) content, antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO) were evaluated in liver, gills, and muscle. Comet assay score and nuclear abnormalities and micronucleated cell frequency were analyzed in peripheral erythrocytes. The responses of these parameters were evaluated in fish exposed (96 h) to environmentally relevant copper concentrations (5, 9 and 20 μg L{sup −1}). In control and copper-exposed fish, no mortality was observed over the experimental period. Almost all biochemical and genetic parameters proved to be affected by waterborne copper exposure. However, the response of catalase activity in liver, ROS, ACAP and LPO in muscle, gills and liver, and DNA damages in erythrocytes clearly showed to be dependent on copper concentration in salt water. Therefore, the use of these parameters could be of relevance in the scope of biomonitoring programs in salt water environments contaminated with copper.

  5. [Waterborne iron migration by groundwater irrigation pumping in a typical irrigation district of Sanjiang Plain].

    Science.gov (United States)

    Zou, Yuan-Chun; Yu, Xiao-Fei; Huo, Li-Li; Lü, Xian-Guo; Jiang, Ming

    2012-04-01

    The iron concentration in groundwater, iron's seasonal migration from groundwater to sun-basked pools, paddy fields and drainage canals, and its distribution in the sediments/soils were observed in the Jiansanjiang Branch Bureau, Heilongjiang Agricultural Cultivation Bureau. The results suggested that the total iron mass concentration of the studied area was (1.73 +/- 0.41) mg x L(-1), ranging from 0.01 to 11.4 mg x L(-1), with the variation coefficient of 1.29%. The annual iron input mass from groundwater to paddy fields and other surface water bodies was 4 976.40 t in 2010, according to the rice planting area and rating irrigation volume. Dissolved Fe2+, Fe3+ and iron, as well as the total iron (dissolved and particle) had seasonal variation, with greater values presented in June and July. These waterborne irons in paddy field waters were greater than those in sun-basked pools and drainage canals. Obvious enrichment effect was observed in sun-basked pools and paddy fields, with their total iron mass concentrations were 6.17 and 21.65 times greater than that in groundwater. Either the total iron or iron oxides in sun-baked pool sediments were greater than that in paddy field soils, field canal and main canal sediments. The differences of the total iron and iron oxides in paddy field soils, field canal and main canal sediments were not significantly different. Considerable irons were precipitated within sun-basked pools and paddy fields during the transfer from groundwater to surface water, with a part of irons exporting into canals through drainage and then precipitated there. Not only the change of total iron mass, but the transformation of iron chemical speciation was observed during the transfer, which was affected by paddy irrigation management directly. The long-term irrigation pumping could cause the substantial enrichment of iron in paddy soils and canal sediments, resulting in the increase of potential pollution risk.

  6. Composites prepared from the waterborne polyurethane cationomers-modified graphene. Part I. Synthesis, structure, and physicochemical properties.

    Science.gov (United States)

    Król, Piotr; Król, Bożena; Pielichowska, Kinga; Špírková, Milena

    In the reaction of 4,4'-methylenebis(phenyl isocyanate), polycaprolactone diol, and N-methyldiethanolamine, they were synthesized aqueous dispersions of polyurethane cationomers, from which films were prepared after adding 0-2 wt% graphene. In order to obtain nanocomposites, graphene was previously noncovalent functionalized in tetrahydrofurane in the field of ultrasound. The chemical structure and the morphology of obtained nanocomposites were analyzed by IR spectroscopy, atomic force microscopy (AFM), and differential scanning calorimetry (DSC) microcalorimetry methods. It was found that the presence of graphene results in increased thermal and mechanical strength of received polymer films and contributes to the increase in hydrophobicity of generally hydrophilic coatings prepared from waterborne polyurethane cationomers. Based on received results, possible interactions between graphene and phase structure of polyurethane cationomers were discussed. Relating to the so far described applications of graphene for the modification of polyurethanes, the novelty of this work is the concept of incorporation of graphene particles to polyurethane cationomer chains exclusively through a simple noncovalent functionalization and to investigate the effect of graphene on the properties obtained in this way of thin polyurethane film.

  7. Synthesis of Waterborne Polyurethane Modiifed by Nano-SiO2 Silicone and Properties of the WPU Coated RDX

    Institute of Scientific and Technical Information of China (English)

    Li Yang; Zhao Tianbo; Qu Xiaoling; Ding Hongjing; Li Fengyan

    2015-01-01

    A series of nano silica/silicone modiifed waterborne polyurethane (WPU) have been synthesized from polytet-ramethylene glycol and isophorone diisocyanate, dihydroxymethyl propionic acid and triethylamine, ethylenediamine, trimethylolpropane, nano-SiO2 and the silane coupling agent KH550. The effect of the dosage of nano-SiO2 on the WPU-Si membrane and the coated RDX (cyclotrimethylenetrinitramine) particles have been studied in terms of their surface prop-erties, mechanical properties, and thermal stability. The results showed that with the increase of Si content, the stability of the emulsion reduced gradually. The material with more Si content displayed an increased thermodynamic stability, an increased high temperature resistance, an increased tensile strength and a decreased elongation at break. With the increase of Si content, the surface tension of the material decreased, the bibulous rate reduced, and the contact angle increased gradually, so that the surface tension of the polyurethane and RDX are close to each other which could improve the performance of coating.

  8. Study on Evolution of Coating State and Role of Graphene in Graphene-Modified Low-Zinc Waterborne Epoxy Anticorrosion Coating by Electrochemical Impedance Spectroscopy

    Science.gov (United States)

    Ding, Rui; Wang, Xiao; Jiang, Jianming; Gui, Taijiang; Li, Weihua

    2017-07-01

    In this paper, corrosion potential and impedance response of the graphene-modified low-zinc waterborne epoxy anticorrosion coating with different compositions were measured experimentally. Microstructure impedance analysis approach was proposed, which was applied to analyze in detail the system impedance and to clarify the variation of coating state as well as the role of graphene in the coating. Results showed that the variation course of coating state was divided into four stages: activation stage; cathodic protection stage; shielding protection stage; and failure stage. Graphene formed numerous isolation layers in the coating to hinder the diffusion of aggressive particles like water and oxygen as well as corrosion products, which played a certain shielding protective role. Moreover, graphene was a good electron conductor, which enabled the outer layer zinc to continue to constitute a galvanic couple with the iron substrate after cathodic protection stage, thereby prolonging the protective effect of the coating to some extent.

  9. Together in the fight against neglected public health problems: worldwide network cooperation on waterborne diseases and emerging parasitic diseases.

    Science.gov (United States)

    Wu, Xiaoying; Song, Langui; Liang, Jinyi; Luo, Shiqi; Mehlhorn, Heinz; Wu, Zhongdao

    2015-05-01

    A symposium held in Guangzhou, China, aimed to become starting point of an international cooperation in the fight against waterborne diseases, which obtain more and more importance in times of global warming and globalization.

  10. 水性聚氨酯的合成及改性%Synthesis and modification of waterborne polyurethane adhesive

    Institute of Scientific and Technical Information of China (English)

    王洪祚; 王颖

    2012-01-01

    The preparation principles,methods and developments of waterborne polyurethancs adhesive were introduced.The major modification methods of waterborne polyurethane adhesive were also reviewed briefly.%对水性聚氨酯胶粘剂的制备原理、方法及研拓进行了扼要介绍,并对其主要改性途径作了简要综.

  11. Study on Preparation and Characterization of a New Cationic Waterborne Polyurethane Emulsion%新型阳离子水性聚氨酯的合成与表征

    Institute of Scientific and Technical Information of China (English)

    刘斌; 王武生; 曾俊

    2012-01-01

    以聚氧化丙烯二元醇(PE220)和异佛尔酮二异氰酸酯(IPDI)为原料,以自制的阳离子亲水单体Y-E51作为扩链剂,制备了阳离子型水性聚氨酯乳液(WPU),讨论了Y -ES1的摩尔分数对WPU乳液粒径分布及胶膜力学性能的影响,并通过红外光谱对产物的结构进行表征.结果表明:随着Y -E51摩尔分数的增加,乳液粒径分布变窄,胶膜的吸收率、甲苯溶胀率变大,拉伸强度增大,断裂伸长率下降;当Y -E51的摩尔分数为18%,胶膜的力学性能最佳.%A cationic waterborne polyurethane emulsion ( WPU) was synthesiszed by using IPDI and polyether glycol( PE220 ) as raw material,and Y - E51as cationic hydrophilic chain-extending agents. The chemical structure of the product was characterized by FT - IR. The influence of mole fraction of Y - E51 on the particle size distributions waterborne polyurethane emulsion and mechanical properties of film were studied. The experiment results showed that particle size distributions of waterborne polyurethane emulsion decreased ,tensile strength of film increased and elongation at break became weak with increasing of mole frac-toon of Y - E51. And when Y -E51 was 18% ,the film showed the best mechanical properties.

  12. The immune responses and expression of metallothionein (MT) gene and heat shock protein 70 (HSP 70) in juvenile rockfish, Sebastes schlegelii, exposed to waterborne arsenic (As(3+)).

    Science.gov (United States)

    Kim, Jun-Hwan; Kang, Ju-Chan

    2016-10-01

    Juvenile rockfish, Sebastes schlegelii (mean length 16.4±1.9cm, and mean weight 71.6±6.4g) were exposed for 20days with the different levels of waterborne arsenic concentration (0, 50, 100, 200 and 400μg/L). The plasma cortisol of S. schlegelii was significantly increased by the waterborne arsenit exposure. In the immune responses, the immunoglobulin M (Ig M) and lysozyme activity of S. schlegelii were significantly increased by the waterborne arsenic exposure. The acetylcholinesterase (AChE) activity of S. schlegelii was inhibited by the waterborne arsenic exposure. The substantial increases in the gene expression such as metallothionein (MT) and heat shock protein 70 (HSP 70) were observed by the waterborne arsenic exposure. The results demonstrated that waterborne arsenic exposure can induce the significant alterations in the immune responses and specific gene expression of S. schlegelii. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. MDI型水性聚氨酯涂料的研究进展%Research Progress of MDI-Based Waterborne Polyurethanes Coatings

    Institute of Scientific and Technical Information of China (English)

    周亭亭; 杨建军; 吴庆云; 吴明元; 张建安

    2011-01-01

    综述了二苯基甲烷二异氰酸酯(MDI)与聚醚型、聚酯型或聚醚-聚酯共混型多元醇反应制备的水性聚氨酯(WPU)涂料的研究进展,简单介绍了MDI型WPU涂料在不同领域的应用,并对MDI型WPU涂料的未来发展前景作了展望.%The MDI-based waterborne polyurethanes coatings including polyether-based waterborne polyurethanes, polyester-based waterborne polyurethanes and polyether-polyester waterborne polyurethanes were summaried. The research progress of MDI-based waterborne polyurethane coatings applied in various fields were intruduced. Finally, the future development of MDI-based waterborne polyurethanes coatings was prospected.

  14. Application of waterborne acrylic emulsions in coated controlled release fertilizer using reacted layer technology

    Institute of Scientific and Technical Information of China (English)

    Yazhen Shen; Cong Zhao; Jianmin Zhou; Changwen Du

    2015-01-01

    Waterborne acrylic emulsions modified with organic siloxanes and aziridine crosslinker were synthesized and applied as coating of controlled release fertilizer. The free films were characterized and the nutrient release pro-files of the coated fertilizers were determined. The results show that methyl silicone oil and methylsilanolate so-dium could not improve water resistance performance and glass transition temperature Tg of coatings, while the firmness is enhanced. Aziridine crosslinker improves the water resistance performance, firmness and Tg. Incorpo-ration of methyl silicone oil and aziridine crosslinker gives an excellent aqueous acrylic emulsion for coated con-trol ed release fertilizer, with the 30-day cumulative nutrient release reduced to 16%and an estimated nutrient release duration over 190 days. Therefore, this waterborne coating is promising to meet the requirements for controlled release of nutrient and environmental protection.

  15. Preparation of Conductive Coating Solutions by Blending Waterborne Acrylic Polyurethane Dispersion with Carbon Nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Woo Young; Yun, Dong Gu; Song, Ki Chang [Konyang University, Nonsan (Korea, Republic of)

    2013-02-15

    Waterborne polyurethane dispersion (WPUD) was synthesized from polycarbonate diol (PCD), isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as starting materials. Then, waterborne acrylic polyurethane dispersion (AUD) was synthesized by reacting the WPUD with an acrylate monomer, methyl methacrylate (MMA). Subsequently, the AUD was mixed with multi-walled carbon nanotube (MWCNT) to yield a conductive coating solution, and the mixture was coated on the polycarbonate substrate. With increasing the amount of MMA in the AUD, the pencil hardness, abrasion resistance and chemical resistance of the coating films were improved, but the electrical conductivity of the coating films was decreased. On the other hand, the pencil hardness, abrasion resistance and chemical resistance of coating films were decreased, but the electrical conductivity was enhanced with increasing the amount of MWCNT in the conductive coating solutions.

  16. Imaging and identification of waterborne parasites using a chip-scale microscope.

    Directory of Open Access Journals (Sweden)

    Seung Ah Lee

    Full Text Available We demonstrate a compact portable imaging system for the detection of waterborne parasites in resource-limited settings. The previously demonstrated sub-pixel sweeping microscopy (SPSM technique is a lens-less imaging scheme that can achieve high-resolution (<1 µm bright-field imaging over a large field-of-view (5.7 mm×4.3 mm. A chip-scale microscope system, based on the SPSM technique, can be used for automated and high-throughput imaging of protozoan parasite cysts for the effective diagnosis of waterborne enteric parasite infection. We successfully imaged and identified three major types of enteric parasite cysts, Giardia, Cryptosporidium, and Entamoeba, which can be found in fecal samples from infected patients. We believe that this compact imaging system can serve well as a diagnostic device in challenging environments, such as rural settings or emergency outbreaks.

  17. Water-borne hyphomycetes in tree canopies of Kaiga (Western Ghats, India

    Directory of Open Access Journals (Sweden)

    Naga M. Sudheep

    2013-12-01

    Full Text Available The canopy samples such as trapped leaf litter, trapped sediment (during summer, stemflow and throughfall (during monsoon from five common riparian tree species (Artocarpus heterophyllus, Cassia fistula, Ficus recemosa, Syzygium caryophyllatum and Xylia xylocarpa in Kaiga forest stand of the Western Ghats of southwest India were evaluated for the occurrence of water-borne hyphomycetes. Partially decomposed trapped leaf litter was incubated in bubble chambers followed by filtration to assess conidial output. Sediments accumulated in tree holes or junction of branches were shaken with sterile leaf disks in distilled water followed by incubation of leaf disks in bubble chamber and filtration to find out colonized fungi. Stemflow and throughfall samples were filtered directly to collect free conidia. From five canopy niches, a total of 29 water-borne hyphomycetes were recovered. The species richness was higher in stemflow and throughfall than trapped leaf litter and sediments (14-16 vs. 6-10 species. Although sediments of Syzygium caryophyllatum were acidic (5.1, the conidial output was higher than other tree species. Stemflow and throughfall of Xylea xylocarpa even though alkaline (8.5-8.7 showed higher species richness (6-12 species as well as conidial load than rest of the tree species. Flagellospora curvula and Triscelophorus acuminatus were common in trapped leaf litter and sediments respectively, while conidia of Anguillospora crassa and A. longissima were frequent in stemflow and throughfall. Diversity of water-borne hyphomycetes was highest in throughfall of Xylea xylocarpa followed by throughfall of Ficus recemosa. Our study reconfirms the occurrence and survival of diverse water-borne hyphomycetes in different niches of riparian tree canopies of the Western Ghats during wet and dry regimes and predicts their possible role in canopy as saprophytes, endophytes and alternation of life cycle between canopy and aquatic habitats.

  18. Waterborne toxoplasmosis investigated and analysed under hydrogeological assessment: new data and perspectives for further research

    OpenAIRE

    2015-01-01

    We present a set of data on human and chicken Toxoplasma gondii seroprevalence that was investigated and analysed in light of groundwater vulnerability information in an area endemic for waterborne toxoplasmosis in Brazil. Hydrogeological assessment was undertaken to select sites for water collection from wells for T. gondii oocyst testing and for collecting blood from free-range chickens and humans for anti-T. gondii serologic testing. Serologic testing of human specimens was done using conv...

  19. Rainfall-runoff model for prediction of waterborne viral contamination in a small river catchment

    Science.gov (United States)

    Gelati, E.; Dommar, C.; Lowe, R.; Polcher, J.; Rodó, X.

    2013-12-01

    We present a lumped rainfall-runoff model aimed at providing useful information for the prediction of waterborne viral contamination in small rivers. Viral contamination of water bodies may occur because of the discharge of sewage effluents and of surface runoff over areas affected by animal waste loads. Surface runoff is caused by precipitation that cannot infiltrate due to its intensity and to antecedent soil water content. It may transport animal feces to adjacent water bodies and cause viral contamination. We model streamflow by separating it into two components: subsurface flow, which is produced by infiltrated precipitation; and surface runoff. The model estimates infiltrated and non-infiltrated precipitation and uses impulse-response functions to compute the corresponding fractions of streamflow. The developed methodologies are applied to the Glafkos river, whose catchment extends for 102 km2 and includes the city of Patra. Streamflow and precipitation observations are available at a daily time resolution. Waterborne virus concentration measurements were performed approximately every second week from the beginning of 2011 to mid 2012. Samples were taken at several locations: in river water upstream of Patras and in the urban area; in sea water at the river outlet and approximately 2 km south-west of Patras; in sewage effluents before and after treatment. The rainfall-runoff model was calibrated and validated using observed streamflow and precipitation data. The model contribution to waterborne viral contamination prediction was benchmarked by analyzing the virus concentration measurements together with the estimated surface runoff values. The presented methodology may be a first step towards the development of waterborne viral contamination alert systems. Predicting viral contamination of water bodies would benefit sectors such as water supply and tourism.

  20. A systematic review of waterborne infections from nontuberculous mycobacteria in health care facility water systems.

    Science.gov (United States)

    Li, Trudy; Abebe, Lydia S; Cronk, Ryan; Bartram, Jamie

    2017-05-01

    Healthcare-acquired infections are an increasing problem for health care providers and policy makers. Water is an overlooked source of infectious microorganisms in health care facilities. Waterborne nontuberculous mycobacteria (NTM) are ubiquitous, and particularly problematic in health care facility water systems, and cause a variety of diseases. The purpose of this review is to assess health care associated NTM infections from health care facility water systems. We documented susceptible populations, modes of transmission, and the median attack rate (e.g. patients infected per patients exposed). We aimed to identify transmission risk factors and inform evidence-based policies for infection control and prevention. We searched Embase, PubMed, Web of Science and clinicaltrials.gov without date restrictions. English language articles with original data on NTM waterborne infections in health care settings were included. Randomized controlled trials, descriptive studies (case reports, case series), case-control studies, cohort studies, cross-sectional surveys, and quasi-experimental studies on nosocomial waterborne infections were included. Three investigators independently screened titles and abstracts for relevant articles, and one screened full-text articles. Data were extracted by one investigator, and a second confirmed accuracy for 10% of results. We included 22 observational studies. Immunocompromised, post-surgical, and hemodialysis patients were commonly affected populations. A range of exposure routes such as uncovered central venous catheters (CVCs), wound exposure, and contamination during surgical procedures was reported. The median attack rate was 12.1% (interquartile range, 11-27.2). Waterborne NTM infection affects susceptible patients through common, preventable exposure routes. Effective prevention strategies will require both medical and environmental health expertise, and inter-professional cooperation will optimize these efforts. Copyright © 2016

  1. River Networks As Ecological Corridors for Species, Populations and Pathogens of Water-Borne Disease

    Science.gov (United States)

    Rinaldo, A.

    2014-12-01

    River basins are a natural laboratory for the study of the integration of hydrological, ecological and geomorphological processes. Moving from morphological and functional analyses of dendritic geometries observed in Nature over a wide range of scales, this Lecture addresses essential ecological processes that take place along dendritic structures, hydrology-driven and controlled, like e.g.: population migrations and human settlements, that historically proceeded along river networks to follow water supply routes; riparian ecosystems composition that owing to their positioning along streams play crucial roles in their watersheds and in the loss of biodiversity proceeding at unprecedented rates; waterborne disease spreading, like epidemic cholera that exhibits epidemic patterns that mirror those of watercourses and of human mobility and resurgences upon heavy rainfall. Moreover, the regional incidence of Schistosomiasis, a parasitic waterborne disease, and water resources developments prove tightly related, and proliferative kidney disease in fish thrives differently in pristine and engineered watercourses: can we establish quantitatively the critical linkages with hydrologic drivers and controls? How does connectivity within a river network affect community composition or the spreading mechanisms? Does the river basin act as a template for biodiversity or for species' persistence? Are there hydrologic controls on epidemics of water-borne disease? Here, I shall focus on the noteworthy scientific perspectives provided by spatially explicit eco-hydrological studies centered on river networks viewed as ecological corridors for species, populations and pathogens of waterborne disease. A notable methodological coherence is granted by the mathematical description of river networks as the support for reactive transport. The Lecture overviews a number of topics idiosyncratically related to my own research work but ideally aimed at a coherent body of materials and methods. A

  2. Preparation and characterization of a mixing soft-segment waterborne polyurethane polymer electrolyte

    Institute of Scientific and Technical Information of China (English)

    Feng Wu; Yue JiaoLi; Ren Jie Chen; Shi Chen

    2009-01-01

    The mixing soft-segment WPU (waterborne polyurethane) polymer electrolytes were synthesized by using PEO (poly(ethylene oxide)) and PDMS (polydimethylsiloxane) as the soft segments. These polymer electrolytes exhibit good thermal and electro-chemical stability. The conductivity of the gel polymer electrolyte is 2.52×10-3 S/cm at 25 ℃ with the LiTFSI/(DMC + EC) content of 130%.

  3. Environmental health aspects of drinking water-borne outbreak due to karst flooding: case study.

    Science.gov (United States)

    Dura, Gyula; Pándics, Tamás; Kádár, Mihály; Krisztalovics, Katalin; Kiss, Zoltánné; Bodnár, Judit; Asztalos, Agnes; Papp, Erzsébet

    2010-09-01

    Climate change may increase the incidence of waterborne diseases due to extreme rainfall events, and consequent microbiological contamination of the water source and supply. As a result of the complexity of the pathways from the surface to the consumer, it is difficult to detect an association between rainfall and human disease. The water supply of a Hungarian city, Miskolc (174,000 inhabitant), is mainly based on karstic water, a vulnerable underground water body. A large amount of precipitation fell on the catchment area of the karstic water source, causing an unusually strong karstic water flow and flooding, and subsequent microbiological contamination. The presence of several potential sources of contamination in the protective zone of the karstic water source should be emphasized. The water supplier was unprepared to treat the risk of waterborne outbreak caused by an extreme weather event. Public health intervention and hygienic measures were taken in line with epidemiological actions, focusing on the protection of consumers by providing safe drinking water. The contamination was identified, and measures were taken for risk reduction and prevention. This case study underlines the increasing importance of preparedness for extreme water events in order to protect the karstic water sources and to avoid waterborne outbreaks.

  4. Waterborne disease-related risk perceptions in the Sonora River basin, Mexico.

    Science.gov (United States)

    Morua, Agustin Robles; Halvorsen, Kathleen E; Mayer, Alex S

    2011-05-01

    Waterborne disease is estimated to cause about 10% of all diseases worldwide. However, related risk perceptions are not well understood, particularly in the developing world where waterborne disease is an enormous problem. We focus on understanding risk perceptions related to these issues in a region within northern Mexico. Our findings show how waterborne disease problems and solutions are understood in eight small communities along a highly contaminated river system. We found major differences in risk perceptions between health professionals, government officials, and lay citizens. Health professionals believed that a high level of human-waste-related risk existed within the region. Few officials and lay citizens shared this belief. In addition, few officials and lay citizens were aware of poor wastewater-management-related disease outbreaks and water contamination. Finally, aside from health professionals, a few interviewees understood the importance of basic hygiene and water treatment measures that could help to prevent disease. Our results add to the literature on environmentally-related risk perceptions in the developing world. We discuss recommendations for improving future human-wastewater-related risk communication within the region.

  5. Generalized reproduction numbers and the prediction of patterns in waterborne disease.

    Science.gov (United States)

    Gatto, Marino; Mari, Lorenzo; Bertuzzo, Enrico; Casagrandi, Renato; Righetto, Lorenzo; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

    2012-11-27

    Understanding, predicting, and controlling outbreaks of waterborne diseases are crucial goals of public health policies, but pose challenging problems because infection patterns are influenced by spatial structure and temporal asynchrony. Although explicit spatial modeling is made possible by widespread data mapping of hydrology, transportation infrastructure, population distribution, and sanitation, the precise condition under which a waterborne disease epidemic can start in a spatially explicit setting is still lacking. Here we show that the requirement that all the local reproduction numbers R0 be larger than unity is neither necessary nor sufficient for outbreaks to occur when local settlements are connected by networks of primary and secondary infection mechanisms. To determine onset conditions, we derive general analytical expressions for a reproduction matrix G0, explicitly accounting for spatial distributions of human settlements and pathogen transmission via hydrological and human mobility networks. At disease onset, a generalized reproduction number Λ0 (the dominant eigenvalue of G0) must be larger than unity. We also show that geographical outbreak patterns in complex environments are linked to the dominant eigenvector and to spectral properties of G0. Tests against data and computations for the 2010 Haiti and 2000 KwaZulu-Natal cholera outbreaks, as well as against computations for metapopulation networks, demonstrate that eigenvectors of G0 provide a synthetic and effective tool for predicting the disease course in space and time. Networked connectivity models, describing the interplay between hydrology, epidemiology, and social behavior sustaining human mobility, thus prove to be key tools for emergency management of waterborne infections.

  6. Competence in water-borne heating systems in buildings; Kompetanse innen vannbaarene varmesystemer i bygg

    Energy Technology Data Exchange (ETDEWEB)

    Jarstein, Stig; Palm, Linn Therese; Naess, Bente Haukland; Nossum, Aase; Johnsen, Morten

    2009-01-15

    Trade participants in water-borne heating systems in buildings has experienced mistakes in all phases and of all participants of a project. When water-borne heating system functions, there is almost no follow up. This report is based on a qualitative survey where a several central participants, who on a daily basis are involved in projects with water-borne heating systems, are interviewed or have participated in focus group meetings. Following points illustrate experiences made by the operators in occasions where competence in trade is insufficiencies and mistakes occur: - Property developer lacks ordering competence and has problems in ordering quality. Consultant submit services of minor quality. Performance is of another quality than the supplier. Administration / maintenance lacks competence in how to run the system and without introduction and training in the heating system they take over a system that is over dimensioned and hard to regulate. The trade as a whole knows all the challenges, but the participants gives mainly the impression that the fault is lac of competence for all the other participants - not them self. This report points out measures and Enova can support competence improving measures which on long term will improve the quality from the participants. The trade is recommended to look into project execution, how competence is involved at the right moment, improving of control and documentation routines and at termination / hand over. (AG).14 refs., 14 figs., 2 tabs

  7. A systematic review of nosocomial waterborne infections in neonates and mothers.

    Science.gov (United States)

    Moffa, Michelle; Guo, Wilson; Li, Trudy; Cronk, Ryan; Abebe, Lydia S; Bartram, Jamie

    2017-08-09

    Water is an important, overlooked, and controllable source of nosocomial infection. Hospitalized neonates and their mothers are particularly vulnerable to nosocomial waterborne infections. Our objectives through this systematic review were to: investigate water sources, reservoirs, and transmission routes that lead to nosocomial waterborne infections in neonates and their mothers; establish patient risk factors; compile measures for controlling outbreaks and recommended strategies for prevention; and identify information gaps to improve guidelines for reporting future outbreaks. We searched PubMed, Web of Science, Embase, and clinicaltrials.gov. Peer-reviewed studies reporting contaminated water as a route of transmission to neonates and/or their mothers were included. Twenty-five studies were included. The most common contaminated water sources in healthcare facilities associated with infection transmission were tap water, sinks, and faucets. Low birthweights, preterm or premature birth, and underlying disease increased neonatal risk of infection. Effective control measures commonly included replacing or cleaning faucets and increased or alternative methods for hand disinfection, and recommendations for prevention of future infections highlighted the need for additional surveillance. The implementation of control measures and recommended prevention strategies by healthcare workers and managing authorities of healthcare facilities and improved reporting of future outbreaks may contribute to a reduction in the incidence of nosocomial waterborne infections in neonates and their mothers. Copyright © 2017 Elsevier GmbH. All rights reserved.

  8. Surveillance for Waterborne Disease Outbreaks Associated with Drinking Water - United States, 2011-2012.

    Science.gov (United States)

    Beer, Karlyn D; Gargano, Julia W; Roberts, Virginia A; Hill, Vincent R; Garrison, Laurel E; Kutty, Preeta K; Hilborn, Elizabeth D; Wade, Timothy J; Fullerton, Kathleen E; Yoder, Jonathan S

    2015-08-14

    Advances in water management and sanitation have substantially reduced waterborne disease in the United States, although outbreaks continue to occur. Public health agencies in the U.S. states and territories* report information on waterborne disease outbreaks to the CDC Waterborne Disease and Outbreak Surveillance System (http://www.cdc.gov/healthywater/surveillance/index.html). For 2011-2012, 32 drinking water-associated outbreaks were reported, accounting for at least 431 cases of illness, 102 hospitalizations, and 14 deaths. Legionella was responsible for 66% of outbreaks and 26% of illnesses, and viruses and non-Legionella bacteria together accounted for 16% of outbreaks and 53% of illnesses. The two most commonly identified deficiencies† leading to drinking water-associated outbreaks were Legionella in building plumbing§ systems (66%) and untreated groundwater (13%). Continued vigilance by public health, regulatory, and industry professionals to identify and correct deficiencies associated with building plumbing systems and groundwater systems could prevent most reported outbreaks and illnesses associated with drinking water systems.

  9. Study of Nano-silver Waterborne Antibacterial Wood Coatings%纳米银水性抗菌木器涂料的研制

    Institute of Scientific and Technical Information of China (English)

    张然; 梁亮; 宛焱; 胡龙

    2015-01-01

    This paper discusses the stable nano-silver colloid with nano silica sol as carrier and glucose as reductant which has characteristics in structure and particle size of the sol.This synthesizing method uses thermal-UV dual curing emulsion as film-forming resin,nano-silver sol as antibacterial agents,and the design of waterborne antibacterial coatings modified by nano-silver.It also explores the effect of nano-sil-ver sol in various mass fractions on antibacterial performance and formaldehyde degradation rate of water-borne wood coatings.The results show when mass fraction of nano-silver sol is 10%,the nano-silver anti-bacterial waterborne wood coatings have satisfactory performance with over 90%antibacterial rate against Escherichia coli and staphylococcus aureus.And after 48 h daylight the volatility of formaldehyde will reach 70%.%以纳米硅溶胶为载体,葡萄糖为还原剂制备出稳定的纳米银溶胶,并对银溶胶的结构和粒径进行表征.选择热-紫外光双重固化乳液作为成膜树脂,以纳米银溶胶作为纳米抗菌剂,设计出纳米银改性水性木器涂料,讨论了不同质量分数的纳米银溶胶对漆膜抗菌性能和降解甲醛效果的影响.结果表明:当纳米银溶胶的质量分数为10%时,该水性抗菌木器涂料的漆膜性能优良,对大肠杆菌和金黄色葡萄球菌的灭菌率达到90%以上,在自然光下处理48 h后对甲醛的去除率可达70%.

  10. 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 ...

  11. Research progress of modified waterborne polyurethanes%水性聚氨酯的改性研究进展

    Institute of Scientific and Technical Information of China (English)

    李梦华; 吴晓青; 郑静; 郑主宜; 田龙

    2013-01-01

    The characters,the recent overseas and domestic research and development of waterborne polyurethanes (WPU) were introduced.The several modification methods of waterborne polyurethanes,such as with silicones,acrylates,epoxy resins and polycarbonates were summarized in this paper.The applications of modified WPU in various fields were described.Viewed from current research situation,the environment friendly WPU will be the development trend in the future.Finally,the future prospect on modified waterborne polyurethanes was given.%介绍了水性聚氨酯(WPU)的特点、国内外研究现状.综述了WPU的几种改性方法:有机硅改性,丙烯酸酯改性,环氧树脂(EP)改性,聚碳酸酯(PCD)改性等,以及改性WPU的性能及应用.最后,对WPU的发展前景作了展望.

  12. Natural populations of shipworm larvae are attracted to wood by waterborne chemical cues.

    Directory of Open Access Journals (Sweden)

    Gunilla B Toth

    Full Text Available The life cycle of many sessile marine invertebrates includes a dispersive planktonic larval stage whose ability to find a suitable habitat in which to settle and transform into benthic adults is crucial to maximize fitness. To facilitate this process, invertebrate larvae commonly respond to habitat-related chemical cues to guide the search for an appropriate environment. Furthermore, small-scale hydrodynamic conditions affect dispersal of chemical cues, as well as swimming behavior of invertebrate larvae and encounter with potential habitats. Shipworms within the family Teredinidae are dependent on terrestrially derived wood in order to complete their life cycle, but very little is known about the cues and processes that promote settlement. We investigated the potential for remote detection of settling substrate via waterborne chemical cues in teredinid larvae through a combination of empirical field and laboratory flume experiments. Natural populations of teredinid larvae were significantly more abundant close to wooden structures enclosed in plankton net compared to empty control nets, clearly showing that shipworm larvae can sense and respond to chemical cues associated with suitable settling substrate in the field. However, the flume experiments, using ecologically relevant flow velocities, showed that the boundary layer around experimental wooden panels was thin and that the mean flow velocity exceeded larval swimming velocity approximately 5 mm (≈ 25 larval body lengths from the panel surface. Therefore, we conclude that the scope for remote detection of waterborne cues is limited and that the likely explanation for the higher abundance of shipworm larvae associated with the wooden panels in the field is a response to a cue during or after attachment on, or very near, the substrate. Waterborne cues probably guide the larva in its decision to remain attached and settle, or to detach and continue swimming and drifting until the next

  13. Copper uptake kinetics and regulation in a marine fish after waterborne copper acclimation

    Energy Technology Data Exchange (ETDEWEB)

    Dang Fei; Zhong Huan [AMCE and Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong); Wang Wenxiong, E-mail: wwang@ust.hk [AMCE and Department of Biology, Hong Kong University of Science and Technology (HKUST), Clear Water Bay, Kowloon (Hong Kong)

    2009-09-14

    The uptake kinetics and regulation of copper in a marine predatory fish, the black sea bream Acanthopagrus schlegeli after acclimation to waterborne Cu were examined, using radiotracer techniques. The dissolved Cu uptake followed a linear pattern during the time of exposure, and the calculated uptake rate constant was 6.24 L kg{sup -1} day{sup -1}. The efflux rate constant was 0.091 day{sup -1} following dietary uptake of Cu, and the dietary assimilation efficiency (AE) of Cu varied between 1.7% and 10.9% after the fish were fed with three types of prey (oysters, clams and brine shrimp). After the fish were acclimated at a nominal concentration of 50 {mu}g Cu L{sup -1} for 14 days, the Cu uptake rate and efflux rate constant did not change significantly, but the Cu body concentrations and metallothionein (MT) concentrations in fish tissues increased significantly. Subcellular Cu distributions were also modified. Significant MT induction was observed in response to increased Cu tissue concentrations, indicating that MT rather than the uptake kinetics may play a primary role in Cu regulation during waterborne Cu acclimation in this marine fish. Moreover, the high Cu efflux may also be important in Cu regulation during long-term exposure. Our modeling calculations indicated that dietary uptake was likely to be the main route for Cu bioaccumulation in the fish, and the relative contribution of waterborne and dietary uptake depended on the bioconcentration factor (BCF) of the prey and ingestion rate of fish.

  14. 汽车用水性涂料的特征及其涂装技术%The Characteristics of Waterborne Coatings for Automobile and Its Painting Technology

    Institute of Scientific and Technical Information of China (English)

    王锡春; 李文刚

    2012-01-01

    The significant of waterborne for coating process, the difficulties of waterborne coating caused by the characteristics of water, the key process condition of waterborne coating, the factors restricting the development of waterborne coatings and their status were introduced. Pointed out that we should vigorously develop waterborne coatings and coating technology%介绍了涂装工艺水性化的意义,水的特征给水性涂装带来的难点,水性涂装的关键工艺条件,制约水性涂料发展的因素及其现状。指出应大力发展水性涂料及其涂装技术。

  15. Synthesis and characterization of yellow water-borne polyurethane using a diol colorant as extender

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A novel and facile method toward a series of yellow water-borne polyurethane was developed by using an intrinsically colored diol in this paper.The yellow aqueous dispersion PCLD-HENA-PU was synthesized based on isophorone diisocyanate(IPDI), polycaprolactonediol(PCLD) and 2,2-dimethylol propionic acid(DMPA) using a yellow diol N,N-bis(2-hydroxyethyl)-4-nitroaniline (HENA) as a chain extender.Due to the complete reaction of OH group in colorant HENA with NCO group in diisocyanate,a series of stable yello...

  16. Water-borne Infections, Weather Variability and Climate Change in Eastern Russia

    Science.gov (United States)

    Tirrell, A.; Naumova, E. N.; Liss, A.

    2012-12-01

    For this project, a time-series analysis of existing data will be used to assess temporal and spatial associations between long-term, seasonal and short-term weather variability and water-borne infectious diseases in several Siberian municipalities. Building on these associations, we will generate estimates of future changes in infectious disease patterns based upon existing forecasts of climate change and likely increases in extreme weather events in Eastern Russia. Finally, we will contemplate the public health implications of these findings, and offer appropriate policy recommendations.

  17. ALLDOS: a computer program for calculation of radiation doses from airborne and waterborne releases

    Energy Technology Data Exchange (ETDEWEB)

    Strenge, D.L.; Napier, B.A.; Peloquin, R.A.; Zimmerman, M.G.

    1980-10-01

    The computer code ALLDOS is described and instructions for its use are presented. ALLDOS generates tables of radiation doses to the maximum individual and the population in the region of the release site. Acute or chronic release of radionuclides may be considered to airborne and waterborne pathways. The code relies heavily on data files of dose conversion factors and environmental transport factors for generating the radiation doses. A source inventory data library may also be used to generate the release terms for each pathway. Codes available for preparation of the dose conversion factors are described and a complete sample problem is provided describing preparation of data files and execution of ALLDOS.

  18. In vitro activities of eight antifungal drugs against 106 waterborne and cutaneous exophiala species.

    Science.gov (United States)

    Najafzadeh, M J; Saradeghi Keisari, M; Vicente, V A; Feng, P; Shamsian, S A A; Rezaei-Matehkolaei, A; de Hoog, G S; Curfs-Breuker, I; Meis, J F

    2013-12-01

    The in vitro activities of eight antifungal drugs against 106 clinical and environmental isolates of waterborne and cutaneous Exophiala species were tested. The MICs and minimum effective concentrations for 90% of the strains tested (n = 106) were, in increasing order, as follows: posaconazole, 0.063 μg/ml; itraconazole, 0.25 μg/ml; micafungin, 1 μg/ml; voriconazole, 2 μg/ml; isavuconazole, 4 μg/ml; caspofungin, 8 μg/ml; amphotericin B, 16 μg/ml; fluconazole, 64 μg/ml.

  19. ELECTROSTATIC INTERACTION HYBRIDS FROM WATER-BORNE CONDUCTIVE POLYANILINE AND INORGANIC PRECURSOR CONTAINING CARBOXYL GROUP

    Institute of Scientific and Technical Information of China (English)

    Jing Luo; Xian-hong Wang; Ji Li; Xiao-jiang Zhao; Fo-song Wang

    2007-01-01

    Electrostatic interaction conductive hybrids were prepared in water/ethanol solution by the sol-gel process from inorganic sol containing carboxyl group and water-borne conductive polyaniline(cPANI).The electrostatic interaction hybrids film displayed 1-2 orders of magnitude higher electrical conductivity in comparison with common hybrids film,showing remarkable conductivity stability against water soaking.Most strikingly,it displayed ideal electrochemical activity even in a solution with pH=14,which enlarged the conducting polyaniline application window to strong alkaline media.

  20. Mechanical properties of a waterborne pressure-sensitive adhesive with a percolating poly(acrylic acid)-based diblock copolymer network: effect of pH.

    Science.gov (United States)

    Gurney, Robert S; Morse, Andrew; Siband, Elodie; Dupin, Damien; Armes, Steven P; Keddie, Joseph L

    2015-06-15

    Copolymerizing an acrylic acid comonomer is often beneficial for the adhesive properties of waterborne pressure-sensitive adhesives (PSAs). Here, we demonstrate a new strategy in which poly(acrylic acid) (PAA) is distributed as a percolating network within a PSA film formed from a polymer colloid. A diblock copolymer composed of PAA and poly(n-butyl acrylate) (PBA) blocks was synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization and adsorbed onto soft acrylic latex particles prior to their film formation. The thin adsorbed shells on the particles create a percolating network that raises the elastic modulus, creep resistance and tensile strength of the final film. When the film formation occurs at pH 10, ionomeric crosslinking occurs, and high tack adhesion is obtained in combination with high creep resistance. The results show that the addition of an amphiphilic PAA-b-PBA diblock copolymer (2.0 wt.%) to a soft latex provides a simple yet effective means of adjusting the mechanical and adhesive properties of the resulting composite film.

  1. Differential effect of waterborne cadmium exposure on lipid metabolism in liver and muscle of yellow catfish Pelteobagrus fulvidraco

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Qi-Liang; Gong, Yuan [Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan 430070 (China); Luo, Zhi, E-mail: luozhi99@mail.hzau.edu.cn [Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan 430070 (China); Zheng, Jia-Lang; Zhu, Qing-Ling [Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan 430070 (China); Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan 430070 (China)

    2013-10-15

    Highlights: •Cd triggered hepatic lipid accumulation through the improvement of lipogenesis. •Lipid homeostasis in muscle after Cd exposure derived from the down-regulation of both lipogenesis and lipolysis. •Our study determines the mechanism of waterborne Cd exposure on lipid metabolism in fish on a molecular level. •Our study indicates the tissue-specific regulatory effect of lipid metabolism under waterborne Cd exposure. -- Abstract: The present study was conducted to investigate the effect of waterborne cadmium (Cd) exposure on lipid metabolism in liver and muscle of juvenile yellow catfish Pelteobagrus fulvidraco. Yellow catfish were exposed to 0 (control), 0.49 and 0.95 mg Cd/l, respectively, for 6 weeks, the lipid deposition, Cd accumulation, the activities and expression level of several enzymes as well as the mRNA expression of transcription factors involved in lipid metabolism in liver and muscle were determined. Waterborne Cd exposure reduced growth performance, but increased Cd accumulation in liver and muscle. In liver, lipid content, the activities and the mRNA expression of lipogenic enzymes (6-phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), fatty acid synthetase (FAS)) and lipoprotein lipase (LPL) activity increased with increasing waterborne Cd concentrations. However, the mRNA expressions of LPL and peroxisome proliferators-activated receptor (PPAR) α were down-regulated by Cd exposure. Carnitine palmitoyltransferase 1 (CPT1) activity as well as the mRNA expressions of CPT1 and PPARγ showed no significant differences among the treatments. In muscle, lipid contents showed no significant differences among the treatments. The mRNA expression of 6PGD, FAS, CPT1, LPL, PPARα and PPARγ were down-regulated by Cd exposure. Thus, our study indicated that Cd triggered hepatic lipid accumulation through the improvement of lipogenesis, and that lipid homeostasis in muscle was probably conducted by the down

  2. Thermal post-treatment alters nutrient release from a controlled-release fertilizer coated with a waterborne polymer

    OpenAIRE

    Zijun Zhou; Changwen Du; Ting Li; Yazhen Shen; Jianmin Zhou

    2015-01-01

    Controlled-release fertilizers (CRF) use a controlled-release technology to enhance the nutrient use efficiency of crops. Many factors affect the release of nutrients from the waterborne polymer-coated CRF, but the effects of thermal post-treatments remain unclear. In this study, a waterborne polyacrylate-coated CRF was post-treated at different temperatures (30 °C, 60 °C, and 80 °C) and durations (2, 4, 8, 12, and 24 h) after being developed in the Wurster fluidized bed. To characterize the ...

  3. Thermal post-treatment alters nutrient release from a controlled-release fertilizer coated with a waterborne polymer

    OpenAIRE

    Zijun Zhou; Changwen Du; Ting Li; Yazhen Shen; Jianmin Zhou

    2015-01-01

    Controlled-release fertilizers (CRF) use a controlled-release technology to enhance the nutrient use efficiency of crops. Many factors affect the release of nutrients from the waterborne polymer-coated CRF, but the effects of thermal post-treatments remain unclear. In this study, a waterborne polyacrylate-coated CRF was post-treated at different temperatures (30 °C, 60 °C, and 80 °C) and durations (2, 4, 8, 12, and 24 h) after being developed in the Wurster fluidized bed. To characterize the ...

  4. Weathering performance of surface of thermally modified wood finished with nanoparticles-modified waterborne polyacrylate coatings

    Science.gov (United States)

    Miklečić, Josip; Turkulin, Hrvoje; Jirouš-Rajković, Vlatka

    2017-06-01

    In this research the samples of thermally modified (TMT) beech wood samples, finished with waterborne polyacrylate clear coatings modified with nano-sized ZnO and TiO2-rutil were naturally and artificially exposed to weathering conditions. To extend the lifetime of wood and maintain its natural look, the research and development of clear coatings with minimal use of harmful chemicals has become very important. Therefore nano-sized inorganic UV absorbers are increasingly used to enhance the durability of the coating and wood substrate, still retaining the transparency of the coating. During exposure the visual inspection was performed, further the changes of colour, gloss and adhesion were recorded. Interaction of the film with the thermally modified substrate surface were studied. Results showed that the addition of TiO2-rutil and ZnO nanoparticles to the waterborne polyacrylate coating improved the colour stability of thermally modified beech-wood. However, nano-sized ZnO increased the cracking and peeling, and caused the loss in adhesion strength of the film on thermally modified beech wood.

  5. Progression of the load of waterborne and intestinal parasitic diseases in the State of Amazonas.

    Science.gov (United States)

    Martins, Marilaine; Lacerda, Marcus Vinícius Guimarães; Monteiro, Wuelton Marcelo; Moura, Marco Antonio Saboia; Santos, Eyde Cristianne Saraiva; Saraceni, Valéria; Saraiva, Maria Graças Gomes

    2015-01-01

    In the State of Amazonas, Brazil, urban expansion together with precarious basic sanitation conditions and human settlement on river banks has contributed to the persistence of waterborne and intestinal parasitic diseases. Time series of the recorded cases of cholera, typhoid fever, hepatitis A and leptospirosis are described, using data from different levels of the surveillance systems. The sources for intestinal parasitosis prevalence data (non-compulsory reporting in Brazil) were Medical Literature Analysis and Retrieval System Online (MEDLINE), Literatura Latino-Americana (LILACS) and the annals of major scientific meetings. Relevant papers and abstracts in all languages were accessed by two independent reviewers. The references cited by each relevant paper were scrutinized to locate additional papers. Despite its initial dissemination across the entire State of Amazonas, cholera was controlled in 1998. The magnitude of typhoid fever has decreased; however, a pattern characterized by eventual outbreaks still remains. Leptospirosis is an increasing cause of concern in association with the annual floods. The overall prevalence of intestinal parasites is high regardless of the municipality and the characteristics of areas and populations. The incidence of hepatitis A has decreased over the past decade. A comparison of older and recent surveys shows that the prevalence of intestinal parasitic diseases has remained constant. The load of waterborne and intestinal parasitic diseases ranks high among the health problems present in the State of Amazonas. Interventions aiming at basic sanitation and vaccination for hepatitis A were formulated and implemented, but assessment of their effectiveness in the targeted populations is still needed.

  6. New waterborne polyurethane-based nanocomposites reinforced with low loading levels of chitin whisker

    Directory of Open Access Journals (Sweden)

    2011-04-01

    Full Text Available New waterborne polyurethane (WPU-based nanocomposites were prepared by incorporating low loading levels of chitin whiskers (ChWs as the nanophase. The resultant WPU/ChW nanocomposites exhibited prominent enhancement in both strength and Young's modulus, and maintained an elongation of greater than ca. 500%. The ChW loading level of 3 wt% showed the maximum tensile strength (28.8 MPa and enhanced Young's modulus (6.5 MPa, ca.1.8- and 2.2-fold over those of neat WPU. The active surface and rigidity of ChW facilitated formation of the interface for stress transferring and contributed to higher stress-endurance. As the ChW loading level increased, self-aggregation of ChWs resulted in a decrease in strength; however, the rigidity of ChW still supported the increase in Young's modulus, and the nanocompositescontaining 5 wt% ChWs had the highest Young's modulus (9.6 MPa. This work enriches the research into achieving high mechanical performance of waterborne polyurethane-based nanocomposites by introducing a natural nanofiller, and this high performance 'green' bionanocomposites will likely have promising prospects.

  7. Urbanization and human health in urban India: institutional analysis of water-borne diseases in Ahmedabad.

    Science.gov (United States)

    Saravanan, V S; Ayessa Idenal, Marissa; Saiyed, Shahin; Saxena, Deepak; Gerke, Solvay

    2016-10-01

    Diseases are rapidly urbanizing. Ageing infrastructures, high levels of inequality, poor urban governance, rapidly growing economies and highly dense and mobile populations all create environments rife for water-borne diseases. This article analyzes the role of institutions as crosscutting entities among a myriad of factors that breed water-borne diseases in the city of Ahmedabad, India. It applies 'path dependency' and a 'rational choice' perspective to understand the factors facilitating the breeding of diseases. This study is based on household surveys of approximately 327 households in two case study wards and intermittent interviews with key informants over a period of 2 years. Principle component analysis is applied to reduce the data and convert a set of observations, which potentially correlate with each other, into components. Institutional analyses behind these components reveal the role of social actors in exploiting the deeply rooted inefficiencies affecting urban health. This has led to a vicious cycle; breaking this cycle requires understanding the political dynamics that underlie the exposure and prevalence of diseases to improve urban health.

  8. A Waterborne Gastroenteritis Outbreak Caused by Norovirus GII.17 in a Hotel, Hebei, China, December 2014.

    Science.gov (United States)

    Qin, Meng; Dong, Xiao-Gen; Jing, Yan-Yan; Wei, Xiu-Xia; Wang, Zhao-E; Feng, Hui-Ru; Yu, Hong; Li, Jin-Song; Li, Jie

    2016-09-01

    Norovirus (NoV) is responsible for an estimated 90 % of all epidemic nonbacterial outbreaks of gastroenteritis worldwide. Waterborne outbreaks of NoV are commonly reported. A novel GII.17 NoV strain emerged as a major cause of gastroenteritis outbreaks in China during the winter of 2014/2015. During this time, an outbreak of gastroenteritis occurred at a hotel in a ski park in Hebei Province, China. Epidemiological investigations indicated that one water well, which had only recently been in use, was the probable source. GII.17 NoV was detected by real-time reverse-transcription polymerase chain reaction from samples taken from cases, from concentrated water samples from water well, and from the nearby sewage settling tank. Nucleotide sequences of NoV extracted from clinical and water specimens were genetically identical and had 99 % homology with Beijing/CHN/2015. All epidemiological data indicated that GII.17 NoV was responsible for this outbreak. This is the first reported laboratory-confirmed waterborne outbreak caused by GII.17 NoV genotype in China. Strengthening management of well drinking water and systematica monitoring of NoV is essential for preventing future outbreaks.

  9. New guidelines for oil spill identification of waterborne petroleum and petroleum products

    Energy Technology Data Exchange (ETDEWEB)

    Faksness, L.G.; Daling, P.S. [SINTEF Energy Research, Trondheim (Norway); Hansen, A.B. [National Environmental Research Inst., Roskilde (Denmark); Kienhuis, P. [RIZA, (Netherlands); Duus, R. [Norwegian Standard Association (Norway)

    2005-07-01

    Advances in interpretive and analytical methods have opened the possibility to improve the existing Nordtest methodology for oil spill identification which was developed in 1991 under the Nordic Council of Ministers. In 2002, the European Committee for Standardization (CEN) established 2 working groups to revise the Nordtest Methodology into the following 2 CEN guidelines: (1) oil spill identification which includes waterborne and petroleum products, and (2) oil spill identification which in addition to including waterborne petroleum and petroleum products, includes analytical methodology and interpretation of results. The revised methodology includes a protocol/decision chart that has 3 tiered levels of analyses and data treatment. The methodology relies on the characterization of diagnostic ratios. The CEN working group intends to use the guidelines as a basis for a national oil spill identification protocol in each European country and for further international use. The methodology can be applied to oil samples of petrogenic origin with boiling points above 200 degrees C, such as crude oils, diesel fuel oils, residual bunker oils, lubricants, and mixtures of oily bilge and sludge samples. It is not intended for automotive gasolines or other light petroleum products. The method has been implemented in most forensic laboratories in Europe and has successfully differentiated between oils from a spill and possible pollution sources. 19 refs., 4 tabs., 10 figs.

  10. Protection of waterborne pathogens by higher organisms in drinking water: a review.

    Science.gov (United States)

    Bichai, Françoise; Payment, Pierre; Barbeau, Benoit

    2008-07-01

    Higher organisms are ubiquitous in surface waters, and some species can proliferate in granular filters of water treatment plants and colonize distribution systems. Meanwhile, some waterborne pathogens are known to maintain viability inside amoebae or nematodes. The well-documented case of Legionella replication within amoebae is only one example of a bacterial pathogen that can be amplified inside the vacuoles of protozoa and then benefit from the protection of a resistant structure that favours its transport and persistence through water systems. Yet the role of most zooplankton organisms (rotifers, copepods, cladocerans) in pathogen transmission through drinking water remains poorly understood, since their capacity to digest waterborne pathogens has not been well characterized to date. This review aims at (i) evaluating the scientific observations of diverse associations between superior organisms and pathogenic microorganisms in a drinking water perspective and (ii) identifying the missing data that impede the establishment of cause-and-effect relationships that would permit a better appreciation of the sanitary risk arising from such associations. Additional studies are needed to (i) document the occurrence of invertebrate-associated pathogens in relevant field conditions, such as distribution systems; (ii) assess the fate of microorganisms ingested by higher organisms in terms of viability and (or) infectivity; and (iii) study the impact of internalization by zooplankton on pathogen resistance to water disinfection processes, including advanced treatments such as UV disinfection.

  11. Waterborne toxoplasmosis investigated and analysed under hydrogeological assessment: new data and perspectives for further research.

    Science.gov (United States)

    Vieira, Flávia Pereira; Alves, Maria da Glória; Martins, Livia Mattos; Rangel, Alba Lucínia Peixoto; Dubey, Jitender Prakash; Hill, Dolores; Bahia-Oliveira, Lilian Maria Garcia

    2015-11-01

    We present a set of data on human and chicken Toxoplasma gondii seroprevalence that was investigated and analysed in light of groundwater vulnerability information in an area endemic for waterborne toxoplasmosis in Brazil. Hydrogeological assessment was undertaken to select sites for water collection from wells for T. gondii oocyst testing and for collecting blood from free-range chickens and humans for anti-T. gondii serologic testing. Serologic testing of human specimens was done using conventional commercial tests and a sporozoite-specific embryogenesis-related protein (TgERP), which is able to differentiate whether infection resulted from tissue cysts or oocysts. Water specimens were negative for the presence of viable T. gondii oocysts. However, seroprevalence in free-range chickens was significantly associated with vulnerability of groundwater to surface contamination (p toxoplasmosis in light of groundwater vulnerability information associated with prevalence in humans estimated by oocyst antigens recognition have implications for the potential role of hydrogeological assessment in researching waterborne toxoplasmosis at a global scale.

  12. Nitrification performance of nitrifying bacteria immobilized in waterborne polyurethane at low ammonia nitrogen concentrations

    Institute of Scientific and Technical Information of China (English)

    Yamei Dong; Zhenjia Zhang; Yongwei Jin; Zhirong Li; Jian Lu

    2011-01-01

    Suspended and waterborne polyurethane immobilized nitrifying bacteria have been adopted for evaluating the effects of environmental changes, such as temperature, dissolved oxygen (DO) concentration and pH, on nitrification characteristics under conditions of low ammonia concentrations.The results showed that nitrification was prone to complete with increasing pH, DO and temperature.Sensitivity analysis demonstrated the effects of temperature and pH on nitrification feature of suspended bacteria were slightly greater than those of immobilized nitrifying bacteria.Immobilized cells could achieve complete nitrification at low ammonia concentrations when DO was sufficient.Continuous experiments were carried out to discuss the removal of ammonia nitrogen from synthetic micropollute source water with the ammonia concentration of about 1 mg/L using immobilized nitrifying bacteria pellets in an up-flow inner circulation reactor under different hydraulic retention times (HRT).The continuous removal rate remains above 80% even under HRT 30 min.The results verified that the waterborne polyurethane immobilized nitrifying bacteria pellets had great potential applications for micro-pollution source water treatment.

  13. Biomarkers of waterborne copper exposure in the guppy Poecilia vivipara acclimated to salt water.

    Science.gov (United States)

    Machado, Anderson Abel de Souza; Hoff, Mariana Leivas Müller; Klein, Roberta Daniele; Cardozo, Janaina Goulart; Giacomin, Marina Mussoi; Pinho, Grasiela Lopes Leães; Bianchini, Adalto

    2013-08-15

    The responses of a large suite of biochemical and genetic parameters were evaluated in tissues (liver, gills, muscle and erythrocytes) of the estuarine guppy Poecilia vivipara exposed to waterborne copper in salt water (salinity 24 ppt). Activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione reductase, and glutathione S-transferase), metallothionein-like protein concentration, reactive oxygen species (ROS) content, antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO) were evaluated in liver, gills, and muscle. Comet assay score and nuclear abnormalities and micronucleated cell frequency were analyzed in peripheral erythrocytes. The responses of these parameters were evaluated in fish exposed (96 h) to environmentally relevant copper concentrations (5, 9 and 20 μg L⁻¹). In control and copper-exposed fish, no mortality was observed over the experimental period. Almost all biochemical and genetic parameters proved to be affected by waterborne copper exposure. However, the response of catalase activity in liver, ROS, ACAP and LPO in muscle, gills and liver, and DNA damages in erythrocytes clearly showed to be dependent on copper concentration in salt water. Therefore, the use of these parameters could be of relevance in the scope of biomonitoring programs in salt water environments contaminated with copper.

  14. Water-borne pressure-sensitive adhesives acrylics modified using amorphous silica nanoparticles

    Directory of Open Access Journals (Sweden)

    Czech Zbigniew

    2016-12-01

    Full Text Available The application of water-borne pressure-sensitive adhesives (PSA based on acrylics is increasing in a variety of industrial areas. The have been used for manufacturing of double sided and carrier free mounting tapes, splicing tapes, marking and sign films, self-adhesive labels, packaging tapes, protective films and diverse high quality medical materials. Nano-sized inorganic fillers can modify diverse adhesive and self-adhesive coating properties such as tack, peel adhesion, shear strength at 20°C and 70°C, and removability Amorphous synthetic silica nanoparticles in form of water dispersions: Ludox PX-30 (30 wt.% silica stabilizing with counter ion sodium, Ludox PT-40 (40 wt.% silica stabilizing with counter ion sodium, Ludox PT-40AS (40 wt.% silica stabilizing with counter ion ammonium, and Ludox PW-50 (50 wt.% silica stabilizing with counter ion sodium (from Grace in concentrations between 1 and 5wt.% were used for modifying of water-born pressure-sensitive adhesive acrylics: Acronal 052, Acronal CR 516 (both BASF and Plextol D273 (Synthomer properties. It has been found in this study that the nano-technologically reinforced system containing of Acronal 052 and amorphous silica Ludox PX-30 showed a great enhancement in tack, peel adhesion and shear strength. In this paper we evaluate the performance of Acronal 052 modified with amorphous silica Ludox PX-30.

  15. Waterborne transmission of protozoan parasites: review of worldwide outbreaks - an update 2004-2010.

    Science.gov (United States)

    Baldursson, Selma; Karanis, Panagiotis

    2011-12-15

    The present update gives a comprehensive review of worldwide waterborne parasitic protozoan outbreaks that occurred and were published globally between January 2004 and December 2010. At least one hundred and ninety-nine outbreaks of human diseases due to the waterborne transmission of parasitic protozoa occurred and were reported during the time period from 2004 to 2010. 46.7% of the documented outbreaks occurred on the Australian continent, 30.6% in North America and 16.5% in Europe. Cryptosporidium spp. was the etiological agent in 60.3% (120) of the outbreaks, Giardia lamblia in 35.2% (70) and other protozoa in 4.5% (9). Four outbreaks (2%) were caused by Toxoplasma gondii, three (1.5%) by Cyclospora cayetanensis. In two outbreaks (1%) Acanthamoeba spp. was identified as the causative agent. In one outbreak, G. lamblia (in 17.6% of stool samples) and Cryptosporidium parvum (in 2.7% of stool samples) as well as Entamoeba histolytica (in 9.4% of stool samples) and Blastocystis hominis (in 8.1% of stool samples) were detected. In those countries that are likely affected most a lack of surveillance systems is noticeable. However, countries that established surveillance systems did not establish an international standardization of reporting systems.

  16. Waterborne zinc alters temporal dynamics of guppy Poecilia reticulata epidermal response to Gyrodactylus turnbulli (Monogenea).

    Science.gov (United States)

    Gheorghiu, Cristina; Marcogliese, David J; Scott, Marilyn E

    2012-03-20

    The present study assessed the histological changes in the epidermis of Poecilia reticulata induced by the combined effects of an ectoparasite Gyrodactylus turnbulli and differing concentrations of waterborne zinc (Zn). Infected guppies were exposed to 0, 15, 30, 60, or 120 µg Zn l-1 and monitored over 3 wk during the exponential increase in parasite numbers on the fish. The fish epidermis responded within 3 d to G. turnbulli infection with a rapid increase in epidermal thickness and a modest increase in number, but not size or composition, of mucous cells. In contrast, in the presence of combined waterborne Zn and infection, mucous cell numbers declined rapidly. As the parasite numbers increased, the epidermis remained thicker than normal, and the number and size of mucous cells decreased. The addition of Zn led to a dramatic thickening of the epidermis during the exponential growth of the parasite population. Mucous cell numbers remained depressed. Temporal changes in mucous cell size were Zn concentration dependent. At 60 µg Zn l-1, cells returned to normal size as infection progressed, whereas they remained extremely small at 120 µg Zn l-1. Changes in mucin composition previously reported in response to Zn alone were subdued in the presence of the parasite except at 60 µg Zn l-1, where all cells contained only acidic mucins. Together these results demonstrate that, on exposure to both Zn and G. turnbulli infection, the epidermal response is initially a protective response to both stressors, and then mainly driven by the increased parasite burden.

  17. 聚酯水性化技术及水性聚酯稳定性研究进展%Development in waterborn technology and product stability of waterborne polyester resins

    Institute of Scientific and Technical Information of China (English)

    刘身凯; 胡剑青; 涂伟萍

    2009-01-01

    The water-borne technology for polyester is reviewed with using different hydrophilic monomers, including trimellitic anhydride, dimethylmalonic acid, UV curable hyperbranched waterborne polyester, as well as sulphonate monomer. Methods to enhance the water resistant performance of the waterborne polyester and the related theory are summarized. The possible trends in development of waterborne polyester resins are prospected.%综述了4种含有不同亲水单体的聚酯水性化技术,包括传统型的以偏苯三酸酐为亲水性单体的水性聚酯、二羟甲基丙酸为亲水性单体的水性聚酯、紫外固化超支化水性聚酯以及磺酸盐型单体的水性聚酯.在此基础上,叙述了提高水性聚酯耐水解稳定性的方法及原理,并指出了水性聚酯的发展趋势.

  18. Risk of waterborne illness via drinking water in the United States.

    Science.gov (United States)

    Reynolds, Kelly A; Mena, Kristina D; Gerba, Charles P

    2008-01-01

    Outbreaks of disease attributable to drinking water are not common in the U.S., but they do still occur and can lead to serious acute, chronic, or sometimes fatal health consequences, particularly in sensitive and immunocompromised populations. From 1971 to 2002, there were 764 documented waterborne outbreaks associated with drinking water, resulting in 575,457 cases of illness and 79 deaths (Blackburn et al. 2004; Calderon 2004); however, the true impact of disease is estimated to be much higher. If properly applied, current protocols in municipal water treatment are effective at eliminating pathogens from water. However, inadequate, interrupted, or intermittent treatment has repeatedly been associated with waterborne disease outbreaks. Contamination is not evenly distributed but rather affected by the number of pathogens in the source water, the age of the distribution system, the quality of the delivered water, and climatic events that can tax treatment plant operations. Private water supplies are not regulated by the USEPA and are generally not treated or monitored, although very few of the municipal systems involved in documented outbreaks exceeded the USEPA's total coliform standard in the preceding 12 mon (Craun et al. 2002). We provide here estimates of waterborne infection and illness risks in the U.S. based on the total number of water systems, source water type, and total populations exposed. Furthermore, we evaluated all possible illnesses associated with the microbial infection and not just gastroenteritis. Our results indicate that 10.7 M infections/yr and 5.4 M illnesses/yr occur in populations served by community groundwater systems; 2.2 M infections/yr and 1.1 M illnesses/yr occur in noncommunity groundwater systems; and 26.0 M infections/yr and 13.0 M illnesses/yr occur in municipal surface water systems. The total estimated number of waterborne illnesses/yr in the U.S. is therefore estimated to be 19.5 M/yr. Others have recently estimated

  19. Preparation and Characterization of Coating Solution Based on Waterborne Polyurethane Dispersion containing Fluorine for Primer on Electro Galvanized Steel Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Chung Keun; Lim, Sung Hyung [Buhmwoo Institute of Technology Research, Hwaseong (Korea, Republic of)

    2015-10-15

    The purpose of this research was to synthesize fluorine modified waterborne polyurethane dispersion (F-WPU) by soap-free (internal emulsifier) emulsion polymerization techniques, to prepare coating solution based on fluorine modified waterborne polyurethane dispersion (F-WPU) and to compare the chemical and thermo-mechanical properties on the electrogalvanized steel sheet. Environmentally friendly F-WPU was prepared with a fluorinated polyol containing 60 wt% of fluorine. There are various ways of combining a wide variety of fluorinated polyols and diisocyanate to exhibit novel properties of waterborne polyurethane dispersion. Components of coating solution were largely divided into 4 kinds i.e., F-WPU, acrylic emulsion, silane coupling agent, and colloidal silicate. F-WPU coating solution on the electro-galvanized steel sheet showed excellent properties of corrosion resistance, alkali resistance and heat resistance, as compared to other coating solutions using a general waterborne resin. The F-WPU coating solution's reliable effects are possibly due to the fluorine atoms incorporated even in a small amount of F-WPU.

  20. Mobilizing community-based health insurance to enhance awareness & prevention of airborne, vector-borne & waterborne diseases in rural India

    NARCIS (Netherlands)

    P. Panda (Pradeep); A. Chakraborty (Arpita); D.M. Dror (David)

    2015-01-01

    textabstractBackground & objectives: Despite remarkable progress in airborne, vector-borne and waterborne diseases in India, the morbidity associated with these diseases is still high. Many of these diseases are controllable through awareness and preventive practice. This study was an attempt to

  1. Anticorrosive performance of waterborne epoxy coatings containing water-dispersible hexagonal boron nitride (h-BN) nanosheets

    Science.gov (United States)

    Cui, Mingjun; Ren, Siming; Chen, Jia; Liu, Shuan; Zhang, Guangan; Zhao, Haichao; Wang, Liping; Xue, Qunji

    2017-03-01

    Homogenous dispersion of hexagonal boron nitride (h-BN) nanosheets in solvents or in the polymer matrix is crucial to initiate their many applications. Here, homogeneous dispersion of hexagonal boron nitride (h-BN) in epoxy matrix was achieved with a water-soluble carboxylated aniline trimer derivative (CAT-) as a dispersant, which was attributed to the strong π-π interaction between h-BN and CAT-, as proved by Raman and UV-vis spectra. Transmission electron microscopy (TEM) analysis confirmed a random dispersion of h-BN nanosheets in the waterborne epoxy coatings. The deterioration process of water-borne epoxy coating with and without h-BN nanosheets during the long-term immersion in 3.5 wt% NaCl solution was investigated by electrochemical measurements and water absorption test. Results implied that the introduction of well dispersed h-BN nanosheets into waterborne epoxy system remarkably improved the corrosion protection performance to substrate. Moreover, 1 wt% BN/EP composite coated substrate exhibited higher impedance modulus (1.3 × 106 Ω cm2) and lower water absorption (4%) than those of pure waterborne epoxy coating coated electrode after long-term immersion in 3.5 wt% NaCl solution, demonstrating its superior anticorrosive performance. This enhanced anticorrosive performance was mainly ascribed to the improved water barrier property of epoxy coating via incorporating homogeneously dispersed h-BN nanosheets.

  2. Surveillance for Waterborne Disease Outbreaks and Other Health Events Associated with Recreational Water -United States, 2007-2008*

    Science.gov (United States)

    Problem/Condition: Since 1978, CDC, the U.S. Environmental Protection Agency, and the Council of State and Territorial Epidemiologists have collaborated on the Waterborne Disease and Outbreak Surveillance System (WBDOSS) for collecting and reporting data on occurrences and causes...

  3. Comparison of Arsenic Concentrations in Carcass and Viscera of Swim-up Rainbow Trout Exposed to Dietary and Waterborne Arsenic

    Science.gov (United States)

    Rainbow trout fry were exposed to arsenic in water only, diet only, or both diet and water in 28-d studies evaluating survival and growth. Diets consisted of Lumbriculus variegatus that were exposed to multiple concentrations of waterborne arsenate for 7d and then fed to test fi...

  4. Molecular characterization of isolates of waterborne Cryptosporidium spp. collected during an outbreak of gastroenteritis in South Burgundy, France.

    Science.gov (United States)

    Dalle, Frédéric; Roz, Pascale; Dautin, Guillaume; Di-Palma, Marc; Kohli, Evelyne; Sire-Bidault, C; Fleischmann, Marie George; Gallay, Anne; Carbonel, Sylvia; Bon, Fabienne; Tillier, Claude; Beaudeau, Pascal; Bonnin, Alain

    2003-06-01

    In September 2001, a waterborne outbreak of gastroenteritis occurred in eastern France. Of 31 fecal samples from symptomatic individuals, 19 tested positive for Cryptosporidium with two PCRs targeting the Hsp70 and the 18S rRNA genes of CRYPTOSPORIDIUM: Sequencing of the PCR fragments produced sequences identical to that of Cryptosporidium parvum genotype 1.

  5. Effects of waterborne Fe(II) on juvenile turbot Scophthalmus maximus: analysis of respiratory rate, hematology and gill histology

    Science.gov (United States)

    Wu, Zhihao; You, Feng; Liu, Hongjun; Liu, Mengxia; Li, Jun; Zhang, Peijun

    2012-03-01

    The concentration of Fe(II) is high in some groundwater supplies used in turbot culture, and the toxicity of waterborne Fe(II) is unknown. We investigated the stress responses of juvenile turbot, Scophthalmus maximus, exposed to Fe(II) of different concentrations (0.01, 0.05, 0.1, 0.5, 1, and 2 mg/L) for 1, 7, 14, and 28 d, under the same ambient conditions of other parameters. Changes in respiratory rate, hematological parameters, and gill structure were determined. The results show that waterborne Fe(II) did not cause severe hematological perturbation to turbot. A low-medium Fe(II) concentration (lower than 0.1 mg/L) could boost the respiratory rate, and caused no or very limited damage to fish. A high Fe(II) concentration (0.1 mg/L or higher), however, caused gill damage, such as vacuoles in branchial lamellae, epithelial necrosis, and hypertrophy of epithelial cells, and even death after extended exposure time. Therefore, excess waterborne Fe(II) and long-term exposure to Fe(II) could be responsible for poor growth and high mortality of turbot in culture. The concentration of waterborne Fe(II) in turbot culture should be kept below 0.1 mg/L.

  6. Exploiting colloidal interfaces to increase dispersion, performance, and pot-life in cellulose nanocrystal/waterborne epoxy composites

    Science.gov (United States)

    Natalie Girouard; Gregory T. Schueneman; Meisha L. Shofner; J. Carson Meredith

    2015-01-01

    In this study, cellulose nanocrystals (CNCs) are incorporated into a waterborne epoxy resin following two processing protocols that vary by order of addition. The processing protocols produce different levels of CNC dispersion in the resulting composites. The more homogeneously dispersed composite has a higher storage modulus and work of fracture at temperatures less...

  7. 阳离子水性聚氨酯的研究进展%Research Progress of Cationic Waterborne Polyurethane

    Institute of Scientific and Technical Information of China (English)

    方舟; 董擎之

    2011-01-01

    随着环保要求的逐步提高,水性聚氨酯越来越受关注,阳离子水性聚氨酯骨架上带有特殊的正电荷,在合成革、涂饰剂、制鞋、涂料,胶黏剂等领域有着优异的应用性能。综述了阳离子水性聚氨酯的合成机理及工艺,对阳离子水性聚氨酯的国内外发展现状及其各种改性方法进行了概述,并对阳离子水性聚氨酯在各领域的应用进行了介绍。%With the increasingly stringency of environmental protection requirements, waterborne polyurethane was concerned by researchers. As cationic waterborne polyurethane has special positive charges in the molecule chain, it shows excellent performance in various fields as synthetic leather, finishing, shoe sole, coatings and adhesives sealants. The synthesis mechanism ar/d process of cationic waterborne polyurethane were introduced ; the development situation and various modifying methods were described. Moreover, application of cationic waterborne polyurethane in various fields was introduced.

  8. Cryptosporidium sp. infections in green turtles, Chelonia mydas, as a potential source of marine waterborne oocysts in the Hawaiian Islands

    Science.gov (United States)

    Graczyk, T.K.; Balazs, G.H.; Work, T.M.; Aguirre, A.A.; Ellis, D.M.; Murakawa, Shawn K. K.; Morris, Robert

    1997-01-01

    For the first time, Cryptosporidium sp. oocysts were identified in fecal and intestinal samples from free-ranging marine turtles, Chelonia mydas, from the Hawaiian Islands. The oocysts produced positive reactions with commercial test kits recommended for the detection of human-infectious waterborne oocysts of Cryptosporidium parvum.

  9. Surveillance for waterborne disease outbreaks associated with drinking water and other nonrecreational water - United States, 2009-2010.

    Science.gov (United States)

    2013-09-06

    Despite advances in water management and sanitation, waterborne disease outbreaks continue to occur in the United States. CDC collects data on waterborne disease outbreaks submitted from all states and territories through the Waterborne Disease and Outbreak Surveillance System. During 2009-2010, the most recent years for which finalized data are available, 33 drinking water-associated outbreaks were reported, comprising 1,040 cases of illness, 85 hospitalizations, and nine deaths. Legionella accounted for 58% of outbreaks and 7% of illnesses, and Campylobacter accounted for 12% of outbreaks and 78% of illnesses. The most commonly identified outbreak deficiencies in drinking water-associated outbreaks were Legionella in plumbing systems (57.6%), untreated ground water (24.2%), and distribution system deficiencies (12.1%), suggesting that efforts to identify and correct these deficiencies could prevent many outbreaks and illnesses associated with drinking water. In addition to the drinking water outbreaks, 12 outbreaks associated with other nonrecreational water were reported, comprising 234 cases of illness, 51 hospitalizations, and six deaths. Legionella accounted for 58% of these outbreaks, 42% of illnesses, 96% of hospitalizations, and all deaths. Public health, regulatory, and industry professionals can use this information to target prevention efforts against pathogens, infrastructure problems, and water sources associated with waterborne disease outbreaks.

  10. Mechanical properties of wood from Pinus sylvestris L. treated with Light Organic Solvent Preservative and with waterborne Copper Azole

    Energy Technology Data Exchange (ETDEWEB)

    Villasante, A.; Laina, R.; Rojas, J. A. M.; Rojas, I. M.; Vignote, S.

    2013-07-01

    Aim of study: To determine the effect on wood from Pinus sylvestris of treatment with preservatives on mechanical properties and to establish the relation between the penetration and compression strenght. Area of study: Spain. Material and methods: 40 samples of defect-free wood from Pinus sylvestris L. were treated with Light Organic Solvent Preservative (Vacsol Azure WR 2601) and 50 with waterborne Copper Azole (Tanalith E 3492). 40 control samples were not treated (water or preservative). Mechanical resistance to static bending, modulus of elasticity and compression strength parallel to the grain were compared with untreated wood. Regression analysis between the penetration and compression strength parallel was done with the samples treated with waterborne preservative. Main results: The results indicate that the treated wood (with either product) presents a statistically significant increase in mechanical resistance in all three mechanical characteristics. The results obtained differ from earlier studies carried out by other authors. There was no correlation between parallel compression strength and the degree of impregnation of the wood with waterborne Copper Azole. The most probable explanation for these results concerns changes in pressure during treatment. The use of untreated control samples instead of samples treated only with water is more likely to produce significant results in the mechanical resistance studies. Research highlights: Treated wood presents a statistically significant increase in MOE, modulus of rupture to static bending and parallel compression strength. There was no correlation between parallel compression strength and the degree of impregnation with waterborne preservative. (Author)

  11. Measurement of waterborne radon in the drinking water of the Dera Ismail Khan city using active and passive techniques

    Directory of Open Access Journals (Sweden)

    Nasir Tabassum

    2015-01-01

    Full Text Available Groundwater is considered to be the second largest contributor to the indoor radon concentration after soil. Therefore, measurement of waterborne radon has remained a point of interest for many researchers. The main objective of this study is to study waterborne radon activity in the city of Dera Ismail Khan. In this context, water samples were collected from different locations of the city and waterborne radon was measured using a pylon vacuum water degassing system and CR-39 based radon detectors. The pylon system measured waterborne radon activities in samples of hand pumps and motor driven pumps varying from 0.015 to 0.066 Bq/L and 0.021 to 0.145 Bq/L with average values of 0.041 ± 0.015 Bq/L and 0.076 ± 0.024 Bq/L, respectively. Whereas CR-39 based measured values ranged from 0.042 to 0.125 Bq/L and 0.075 to 0.158 Bq/L with average values of 0.081 ± 0.021 Bq/L and 0.120 ± 0.020 Bq/L, respectively. The estimated average annual effective dose due to ingestion of radon from drinking water using pylon and CR-39 based radon detectors for hand and motor pump samples was found to be 1.055×10-4 mSv and 1.947×10-4 mSv, and 2.067×10-4 mSv and 3.058×10-4 mSv, respectively. The waterborne radon concentrations and as a result the annual effective dose expected to be received from it are within the recommended safe limits.

  12. Mechanical properties of wood from Pinus sylvestris L. treated with Light Organic Solvent Preservative and with waterborne Copper Azole

    Directory of Open Access Journals (Sweden)

    A.M. Villasante

    2013-12-01

    Full Text Available Aim of study: To determine the effect on wood from Pinus sylvestris of treatment with preservatives on mechanical properties and to establish the relation between the penetration and compression strength.Area of study: SpainMaterial and Methods: 40 samples of defect-free wood from Pinus sylvestris L. were treated with Light Organic Solvent Preservative (Vacsol Azure WR 2601 and 50 with waterborne Copper Azole (Tanalith E 3492. 40 control samples were not treated (water or preservative. Mechanical resistance to static bending, modulus of elasticity and compression strength parallel to the grain were compared with untreated wood. Regression analysis between the penetration and compression strength parallel was done with the samples treated with waterborne preservative.Main results: The results indicate that the treated wood (with either product presents a statistically significant increase in mechanical resistance in all three mechanical characteristics. The results obtained differ from earlier studies carried out by other authors.There was no correlation between parallel compression strength and the degree of impregnation of the wood with waterborne Copper Azole . The most probable explanation for these results concerns changes in pressure during treatment.The use of untreated control samples instead of samples treated only with water is more likely to produce significant results in the mechanical resistance studies.Research highlights: Treated wood presents a statistically significant increase in MOE, modulus of rupture to static bending  and parallel compression strength.There was no correlation between parallel compression strength and the degree of impregnation with waterborne preservative.Keywords: Light Organic Solvent Preservative; MOE; parallel compression; static bending; waterborne Copper Azole; wood technology.

  13. Waterborne cadmium and nickel impact oxidative stress responses and retinoid metabolism in yellow perch

    Energy Technology Data Exchange (ETDEWEB)

    Defo, Michel A. [Institut national de la recherche scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec, Québec G1K 9A9 (Canada); Bernatchez, Louis [Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec, Québec G1V 0A6 (Canada); Campbell, Peter G.C. [Institut national de la recherche scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec, Québec G1K 9A9 (Canada); Couture, Patrice, E-mail: patrice.couture@ete.inrs.ca [Institut national de la recherche scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec, Québec G1K 9A9 (Canada)

    2014-09-15

    Highlights: • Cd and Ni affected indicators of retinoid metabolism and oxidative stress in fish. • Liver rdh-2 transcription levels increase in fish exposed to waterborne Cd. • Liver REH and LdRAT activities increase with increasing kidney Cd concentration. • Changes at molecular levels do not always mean changes at the functional levels. • Multi-level biological approaches are needed when assessing fish metal toxicology. - Abstract: In this experiment, we studied the transcriptional and functional (enzymatic) responses of yellow perch (Perca flavescens) to metal stress, with a focus on oxidative stress and vitamin A metabolism. Juvenile yellow perch were exposed to two environmentally relevant concentrations of waterborne cadmium (Cd) and nickel (Ni) for a period of 6 weeks. Kidney Cd and Ni bioaccumulation significantly increased with increasing metal exposure. The major retinoid metabolites analyzed in liver and muscle decreased with metal exposure except at high Cd exposure where no variation was reported in liver. A decrease in free plasma dehydroretinol was also observed with metal exposure. In the liver of Cd-exposed fish, both epidermal retinol dehydrogenase 2 transcription level and corresponding enzyme activities retinyl ester hydrolase and lecithin dehydroretinyl acyl transferase increased. In contrast, muscle epidermal retinol dehydrogenase 2 transcription level decreased with Cd exposure. Among antioxidant defences, liver transcription levels of catalase, microsomal glutathione-S-transferase-3 and glucose-6-phosphate dehydrogenase were generally enhanced in Cd-exposed fish and this up-regulation was accompanied by an increase in the activities of corresponding enzymes, except for microsomal glutathione-S-transferase. No consistent pattern in antioxidant defence responses was observed between molecular and biochemical response when fish were exposed to Ni, suggesting a non-synchronous response of antioxidant defence in fish exposed to

  14. Study on preparation and properties of chlorinated polypropylene-graft modification the anionic waterborne polyurethane%氯化聚丙烯改性阴离子型水性聚氨酯的制备与性能研究

    Institute of Scientific and Technical Information of China (English)

    王若鹏; 许戈文; 黄毅萍

    2015-01-01

    Based on polyester polyol( PBA ),dimethylolpropionic acid( DMPA ),isophorone diisocyanate (IPDI)and different grafting rate of maleic anhydride-chlorinated polypropylene polymer,the anionic waterborne polyurethane was synthesized. The emulsion stability test indicate that emulsion stability is good when the grafted rate was 1 . 5%,then waterborne polyurethane grafted products were synthesized with different content of grafted rate of 1 . 5%. Particle size test shows that the particle size of the emulsion gradually increase with the adding of graft copolymer;The mechanics performance test shows that the ten-sile strength and elongation at break of the films are greatly improved;the bonding strength for PP film in-creases. The TGA analysis shows that the thermal property has a certain degree of decline. Overall consid-eration,the waterborne polyurethane emulsion performance is better when the addition amount is 5%.%聚酯多元醇( PBA)、二羟甲基丙酸( DMPA)和异佛尔酮二异氰酸酯( IPDI)为主要原料,加入接枝马来酸酐的氯化聚丙烯( MCPP),合成了氯化聚丙烯改性的阴离子型水性聚氨酯。乳液稳定性测试表明,马来酸酐接枝率为1.5%时水性聚氨酯乳液稳定性较好;粒径测试表明,乳液粒径随着MCPP的加入量增大而逐渐变大;力学性能测试结果显示,经过MCPP改性后,乳液形成胶膜的拉伸强度和断裂伸长率都有明显的提高,对于PP薄膜的粘接性能得到改善。但TGA测试显示随着MCPP量的增加,胶膜的耐热性下降。综合分析得出,MCPP加入量为5%时得到的改性水性聚氨酯性能较佳。

  15. Oxyhydroxy Silicate Colloids: A New Type of Waterborne Actinide(IV) Colloids

    Science.gov (United States)

    Weiss, Stephan; Hennig, Christoph; Brendler, Vinzenz; Ikeda‐Ohno, Atsushi

    2016-01-01

    Abstract At the near‐neutral and reducing aquatic conditions expected in undisturbed ore deposits or in closed nuclear waste repositories, the actinides Th, U, Np, and Pu are primarily tetravalent. These tetravalent actinides (AnIV) are sparingly soluble in aquatic systems and, hence, are often assumed to be immobile. However, AnIV could become mobile if they occur as colloids. This review focuses on a new type of AnIV colloids, oxyhydroxy silicate colloids. We herein discuss the chemical characteristics of these colloids and the potential implication for their environmental behavior. The binary oxyhydroxy silicate colloids of AnIV could be potentially more mobile as a waterborne species than the well‐known mono‐component oxyhydroxide colloids. PMID:27957406

  16. High solid and high stability waterborne polyurethanes via ionic groups in soft segments and chain termini.

    Science.gov (United States)

    Lee, S K; Kim, B K

    2009-08-01

    High solid and high stability waterborne polyurethanes were molecularly designed and synthesized. The positions and concentrations of the anionic groups were varied, along with the molecular weights of the polyol. It was found that the dispersions containing ionic groups at the chain termini (called terminal ions) gave the smallest dispersion size, and the highest dispersion stability and viscosity, whereas the hard ions, containing ionic groups in the hard segments, resulted in the greatest swelling in water. However, the mechanical and dynamic mechanical properties of the dispersion cast films were similar. It was demonstrated that highly stable dispersions with a high solid content (45%) can be obtained at a low ionic content (2%) by simply incorporating the ionic groups at the flexible chain ends. The results were interpreted in terms of the high mobility and low free energy of the chain ends.

  17. Effect of Nanoalumina on the Electrochemical and Mechanical Properties of Waterborne Polyurethane Composite Coatings

    Directory of Open Access Journals (Sweden)

    Shailesh K. Dhoke

    2013-01-01

    Full Text Available A nanocomposite coating was formed by incorporating nanoalumina pigment in a waterborne polyurethane dispersion (WPUD to different loading levels (0.1% and 1.0% by weight. Electrochemical performance of the nanocomposite coating was evaluated by applying these nanomodified coatings on mild steel substrate and exposing them to salt-spray, humidity, and accelerated UV weathering. The surface morphology of the composite coating was evaluated using various analytical techniques. SEM and AFM were used to investigate the dispersion of nanoalumina pigment and surface morphological changes of the nanomodified coating, before and after exposure to the test environment. Mechanical properties like scratch resistance were studied by using nanoscratch technique (Nanoindenter TI-900, Hysitron Inc, USA and hardness using pencil hardness test method. The results showed an improvement in the corrosion, UV weathering, and mechanical properties of the coatings at lower concentration (0.1% by wt, indicating the positive effect of addition of nanoalumina pigment to the coating.

  18. Cure Behaviors and Water Up-take Evaluation of a New Waterborne Epoxy Resin

    Institute of Scientific and Technical Information of China (English)

    WAN Tao; ZANG Tianshun; ZHANG Rui; SUN Xianchang

    2012-01-01

    Cure behaviors and water up-take evaluation of a low cost,ecofriendly and water soluble epoxy resin prepared by reaction between epichlorohydrin and PEG400,PEG600 and PEG1000,respectively,were investigated using non-isothermal differential scanning calorimetry (DSC) and gravimetrical method,respectively.Factors affecting the cure behaviors as well as water up-take of waterborne epoxy resins,such as amount of triethylenetetramine (TETA) and triethylene diamine (TEDA),PEG molecular weight,curing temperature,were systematically investigated.The prepared water soluble epoxy resins can be cured under room temperature with the shape of the curing curves similar to that expected for an autocatalytic reaction.

  19. Performance of waterborne acrylic surface coatings on wood impregnated with Cu-ethanolamine preservatives

    Indian Academy of Sciences (India)

    M Humar; M Pavlič; D Žlindra; M Tomažič; M Petrič

    2011-02-01

    Two waterborne acrylic coatings were applied on spruce wood, impregnated with two copperethanolamine containing preservatives (CuE and CuEQ), one of them (CuEQ) containing a boron compound, octanoic acid and a quaternary ammonium compound as additives. Lower contact angles and deeper penetration of both coating types were observed on CuEQ treated, compared to untreated or CuE-treated wood. Improved adhesion of coatings on CuEQ impregnated wood was exhibited as well. In general, characteristics of surface finishes on copper-ethanolamine treated wood were comparable to untreated wood. It was also shown that copper leaching from the preserved wood was significantly reduced by application of the surface finishes.

  20. The effect of polyether functional polydimethylsiloxane on surface and thermal properties of waterborne polyurethane

    Science.gov (United States)

    Zheng, Guikai; Lu, Ming; Rui, Xiaoping

    2017-03-01

    Waterborne polyurethanes (WPU) modified with polyether functional polydimethylsiloxane (PDMS) were synthesized by pre-polymerization method using isophorone diisocyanate (IPDI) and 1,4-butanediol (BDO) as hard segments and polybutylene adipate glycol (PBA) and polyether functional PDMS as soft segments. The effect of polyether functional PDMS on phase separation, thermal properties, surface properties including surface composition, morphology and wettability were investigated by FTIR, contact angle measurements, ARXPS, SEM-EDS, AFM, TG and DSC. The results showed that the compatibility between urethane hard segment and PDMS modified with polyether was good, and there was no distinct phase separation in both bulk and surface of WPU films. The degradation temperature and low temperature flexibility increased with increasing amounts of polyether functional PDMS. The enrichment of polyether functional PDMS with low surface energy on the surface imparted excellent hydrophobicity to WPU films.

  1. Workshop on Functional Requirements for the Modeling of Fate and Transport of Waterborne CBRN Materials

    Energy Technology Data Exchange (ETDEWEB)

    Giles, GE

    2005-02-03

    The purpose of this Workshop on ''Functional Requirements for the Modeling of Fate and Transport of Waterborne CBRN Materials'' was to solicit functional requirements for tools that help Incident Managers plan for and deal with the consequences of industrial or terrorist releases of materials into the nation's waterways and public water utilities. Twenty representatives attended and several made presentations. Several hours of discussions elicited a set of requirements. These requirements were summarized in a form for the attendees to vote on their highest priority requirements. These votes were used to determine the prioritized requirements that are reported in this paper and can be used to direct future developments.

  2. Mechanical Properties and Morphology of the Clay/Waterborne Polyurethane Nanocomposite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yongcheng; WANG Junwei; ZHAO Yuhua; KANG maoqing; WANG Xinkui

    2006-01-01

    Stable clay/waterborne polyurethane nanocompostie dispersions were synthesized by sulfonated poly ( butylene adipate ) diol , 4,4-diphenylmethane diisocyanate , dimethyl propionic acid, 1,4-butanediol, triethyl anine and clay-water dispersion through a route named prepolymer acetone mixing progress. The reinforced mechanical properties and thermal resistance of films casting from it were examined by dynamic mechanical analyses (DMA), thermogravimetric analyses (TGA) and tensile tests. Furthermore, the morphology of these nanocompostie films and dispersions were observed by transmission electron microscopy (TEM), scanning electron microscopy( SEM), wide-angle X-ray diffraction analyses( WXRD ). The experimental results reveal that the clay could be predominantly dispersed in the pristine polymer forming nanocomposties, and evidendy enhanced the tensile properties and modulus of it. Additionally, the best-reinforced effect could occur when the clay content was near 1 wt% .

  3. Autonomic healable waterborne organic-inorganic polyurethane hybrids based on aromatic disulfide moieties

    Directory of Open Access Journals (Sweden)

    R. H. Aguirresarobe

    2017-04-01

    Full Text Available Aromatic disulfide dynamic structures were incorporated as chain extenders in waterborne organic-inorganic polyurethane hybrids in order to provide autonomic healable characteristics. The synthesis was carried out following the acetone process methodology and the influence of the introduction of the healing agents in the polymer dispersion stability was analyzed. After the crosslinking process at room temperature, organic-inorganic hybrid films, which presented autonomic healing characteristics, were obtained. These features were evaluated by means of stress-strain tests and the films showed repetitive healing abilities. Thus, the optimum healing time at room temperature (25 °C as well as the influence of different parameters in the healing efficiency, such the aromatic disulfide concentration or the physical properties of the polymer matrix were analyzed.

  4. Investigation of ultraviolet curable waterborne polyurethane acrylate dispersion based on hydroxyl-terminated polybutadiene

    Institute of Scientific and Technical Information of China (English)

    NIU Zhenbin; ZHANG Xingyuan; DAI Jiabing; ZHANG Heping

    2007-01-01

    A new kind of ultraviolet (UV) curable waterborne polyurethane acrylate dispersion was synthesized based on hydroxyl-terminated polybutadiene (HTPB),poly(propylene glycol) (PPG),isophorene diisocyanate (IPDI),2-hydroxy ethyl acrylate (HEA) and dimethylol propionic acid (DMPA) after neutralizing by triethylamine (TEA).2-Hydroxy- 1-[4-(2-hydroxyethoxy) phenyl]-2-methyl-1-propanone (Irgacure 2959) was used as a photoinitiator and deionized water as a diluent.Fourier transform infrared (FTIR) analysis was used to identify the chain structure of the UV-curable polyurethane prepolymer based on HTPB and the curing process.Effects of relative content of HTPB and PPG on emulsion stability,resistance to water and ethanol,thermal stability,compatibility of soft and hard segment,as well as the mechanical property of the cured film were investigated.

  5. Waterborne polyurethane single-ion electrolyte from aliphatic diisocyanate and various molecular length of polyethylene glycol

    Directory of Open Access Journals (Sweden)

    2007-03-01

    Full Text Available The waterborne polyurethane (WPU dispersions from the reaction of cycloaliphatic diisocyanates [4,4’-methylenebis(cyclohexyl isocyanate (H12MDI and isophorone diisocyanate (IPDI] and polyethylene glycol (PEG with various molecular lengths were synthesized using our modified acetone process. Differetial scanning calorimeter (DSC and Fourier transform infrared spectroscopy (FTIR were utilized to characterize WPU films for the behavior of their crystallinity and H-bonding of WPU films. The Tg value of WPU increases with increasing the molecular length of PEG, whereas the Tm of WPU decreases with increasing PEG length. Alternating current (AC impedance experiments were performed to determine the ionic conductivities of WPU films. The WPU gel electrolytes exhibits an ionic conductivity as high as ~ 10-5 S/cm at room temperature.

  6. The importance of waterborne disease outbreak surveillance in the United States

    Directory of Open Access Journals (Sweden)

    Gunther Franz Craun

    2012-12-01

    Full Text Available Analyses of the causes of disease outbreaks associated with contaminated drinking water in the United States have helped inform prevention efforts at the national, state, and local levels. This article describes the changing nature of disease outbreaks in public water systems during 1971-2008 and discusses the importance of a collaborative waterborne outbreak surveillance system established in 1971. Increasing reports of outbreaks throughout the early 1980s emphasized that microbial contaminants remained a health-risk challenge for suppliers of drinking water. Outbreak investigations identified the responsible etiologic agents and deficiencies in the treatment and distribution of drinking water, especially the high risk associated with unfiltered surface water systems. Surveillance information was important in establishing an effective research program that guided government regulations and industry actions to improve drinking water quality. Recent surveillance statistics suggest that prevention efforts based on these research findings have been effective in reducing outbreak risks especially for surface water systems.

  7. Glass wool filters for concentrating waterborne viruses and agricultural zoonotic pathogens

    Science.gov (United States)

    Millen, Hana T.; Gonnering, Jordan C.; Berg, Ryan K.; Spencer, Susan K.; Jokela, William E.; Pearce, John M.; Borchardt, Jackson S.; Borchardt, Mark A.

    2012-01-01

    The key first step in evaluating pathogen levels in suspected contaminated water is concentration. Concentration methods tend to be specific for a particular pathogen group, for example US Environmental Protection Agency Method 1623 for Giardia and Cryptosporidium1, which means multiple methods are required if the sampling program is targeting more than one pathogen group. Another drawback of current methods is the equipment can be complicated and expensive, for example the VIRADEL method with the 1MDS cartridge filter for concentrating viruses2. In this article we describe how to construct glass wool filters for concentrating waterborne pathogens. After filter elution, the concentrate is amenable to a second concentration step, such as centrifugation, followed by pathogen detection and enumeration by cultural or molecular methods. The filters have several advantages. Construction is easy and the filters can be built to any size for meeting specific sampling requirements. The filter parts are inexpensive, making it possible to collect a large number of samples without severely impacting a project budget. Large sample volumes (100s to 1,000s L) can be concentrated depending on the rate of clogging from sample turbidity. The filters are highly portable and with minimal equipment, such as a pump and flow meter, they can be implemented in the field for sampling finished drinking water, surface water, groundwater, and agricultural runoff. Lastly, glass wool filtration is effective for concentrating a variety of pathogen types so only one method is necessary. Here we report on filter effectiveness in concentrating waterborne human enterovirus, Salmonella enterica, Cryptosporidium parvum, and avian influenza virus.

  8. Monitoring of Waterborne Parasites in Two Drinking Water Treatment Plants: A Study in Sarawak, Malaysia

    Science.gov (United States)

    Richard, Reena Leeba; Ithoi, Init; Abd Majid, Mohamad Azlan; Wan Sulaiman, Wan Yusoff; Tan, Tian Chye; Nissapatorn, Veeranoot; Lim, Yvonne Ai Lian

    2016-01-01

    The occurrence of waterborne parasites coupled with water parameters at various processing sites of two drinking water treatment plants (A and B) and seven distribution system (DS) sites in Sarawak, Malaysia were studied. Ten liters of water underwent immunomagnetic separation (IMS) technique to detect the presence of Giardia and Cryptosporidium (oo)cysts. The remaining supernatant was used to detect other parasites whilst 50 mL of water sample was each used in the detection of free-living amoebae and fecal coliforms. Sampled water was positive for Giardia (32.9%; 28/85), Cryptosporidium (18.8%; 16/85) followed by Spirometra ova-like (25.9%; 22/85), Blastocystis-like (25.9%; 22/85), nematode larvae-like (8.2%; 7/85) and Taenia ova-like (1.2%; 1/85). Meanwhile, 90.2% (55/61) samples were positive for Acanthamoeba and Naegleria via cultivation and of these, 11 isolates were confirmed as Acanthamoeba genotype T3 (5/7) and T4 (2/7) followed by Naegleria sp. (4/11), Naegleria italica (2/11), Naegleria australiensis (1/11), Naegleria angularis (1/11) and Vahlkampfia sp. (3/11). Cryptosporidium, Acanthamoeba and Naegleria were also detected in one of the seven tested DS sites. Only Giardia and Cryptosporidium showed significant correlations with fluoride and fecal coliforms. These results describe the occurrence of waterborne parasites that will assist key stakeholders in mitigating contamination at the specific sites. PMID:27367710

  9. Monitoring of Waterborne Parasites in Two Drinking Water Treatment Plants: A Study in Sarawak, Malaysia

    Directory of Open Access Journals (Sweden)

    Reena Leeba Richard

    2016-06-01

    Full Text Available The occurrence of waterborne parasites coupled with water parameters at various processing sites of two drinking water treatment plants (A and B and seven distribution system (DS sites in Sarawak, Malaysia were studied. Ten liters of water underwent immunomagnetic separation (IMS technique to detect the presence of Giardia and Cryptosporidium (oocysts. The remaining supernatant was used to detect other parasites whilst 50 mL of water sample was each used in the detection of free-living amoebae and fecal coliforms. Sampled water was positive for Giardia (32.9%; 28/85, Cryptosporidium (18.8%; 16/85 followed by Spirometra ova-like (25.9%; 22/85, Blastocystis-like (25.9%; 22/85, nematode larvae-like (8.2%; 7/85 and Taenia ova-like (1.2%; 1/85. Meanwhile, 90.2% (55/61 samples were positive for Acanthamoeba and Naegleria via cultivation and of these, 11 isolates were confirmed as Acanthamoeba genotype T3 (5/7 and T4 (2/7 followed by Naegleria sp. (4/11, Naegleria italica (2/11, Naegleria australiensis (1/11, Naegleria angularis (1/11 and Vahlkampfia sp. (3/11. Cryptosporidium, Acanthamoeba and Naegleria were also detected in one of the seven tested DS sites. Only Giardia and Cryptosporidium showed significant correlations with fluoride and fecal coliforms. These results describe the occurrence of waterborne parasites that will assist key stakeholders in mitigating contamination at the specific sites.

  10. Reproductive consequences of exposure to waterborne phytoestrogens in male fighting fish Betta splendens.

    Science.gov (United States)

    Stevenson, Louise M; Brown, Alexandria C; Montgomery, Tracy M; Clotfelter, Ethan D

    2011-04-01

    Phytoestrogens are plant compounds that can act as endocrine disruptors in vertebrates. Biologically active levels of phytoestrogens have been found in aquatic habitats near wood pulp and paper mills, biofuel manufacturing plants, sewage-treatment plants, and agricultural fields. Phytoestrogens are known to cause hormonal and gonadal changes in male fish, but few studies have connected these effects to outcomes relevant to reproductive success. In one experiment, we exposed sexually mature male fighting fish Betta splendens to environmentally relevant (1 μg L(-1)) and pharmacological concentrations (1000 μg L(-1)) of the phytoestrogen genistein as well as to a positive control of waterborne 17β-estradiol (E2; 1 μg L(-1)), and a negative control of untreated water. In a second experiment, we exposed male B. splendens to environmentally relevant concentrations (1 μg L(-1)) of genistein and β-sitosterol singly and in combination as well as to the positive and negative controls. All exposures were 21 days in duration. We measured sex-steroid hormone levels, gonadosomatic index (GSI), sperm concentration and motility, and fertilization success in these fish. We found that exposure to genistein did not affect circulating levels of the androgen 11-ketotestosterone or the estrogen E2 relative to negative-control fish. We also found that neither of the compounds nor their mixture affected GSI, sperm concentration or motility, or fertilization success in exposed fish relative to negative-control fish. However, fish exposed to phytoestrogens showed some evidence of fewer but more motile sperm than fish exposed to the positive control E2. We conclude that sexually mature male B. splendens are relatively immune to reproductive impairments from short-term exposure to waterborne phytoestrogens.

  11. Monitoring of Waterborne Parasites in Two Drinking Water Treatment Plants: A Study in Sarawak, Malaysia.

    Science.gov (United States)

    Richard, Reena Leeba; Ithoi, Init; Abd Majid, Mohamad Azlan; Wan Sulaiman, Wan Yusoff; Tan, Tian Chye; Nissapatorn, Veeranoot; Lim, Yvonne Ai Lian

    2016-06-28

    The occurrence of waterborne parasites coupled with water parameters at various processing sites of two drinking water treatment plants (A and B) and seven distribution system (DS) sites in Sarawak, Malaysia were studied. Ten liters of water underwent immunomagnetic separation (IMS) technique to detect the presence of Giardia and Cryptosporidium (oo)cysts. The remaining supernatant was used to detect other parasites whilst 50 mL of water sample was each used in the detection of free-living amoebae and fecal coliforms. Sampled water was positive for Giardia (32.9%; 28/85), Cryptosporidium (18.8%; 16/85) followed by Spirometra ova-like (25.9%; 22/85), Blastocystis-like (25.9%; 22/85), nematode larvae-like (8.2%; 7/85) and Taenia ova-like (1.2%; 1/85). Meanwhile, 90.2% (55/61) samples were positive for Acanthamoeba and Naegleria via cultivation and of these, 11 isolates were confirmed as Acanthamoeba genotype T3 (5/7) and T4 (2/7) followed by Naegleria sp. (4/11), Naegleria italica (2/11), Naegleria australiensis (1/11), Naegleria angularis (1/11) and Vahlkampfia sp. (3/11). Cryptosporidium, Acanthamoeba and Naegleria were also detected in one of the seven tested DS sites. Only Giardia and Cryptosporidium showed significant correlations with fluoride and fecal coliforms. These results describe the occurrence of waterborne parasites that will assist key stakeholders in mitigating contamination at the specific sites.

  12. Coupled dynamics of energy budget and population growth of tilapia in response to pulsed waterborne copper.

    Science.gov (United States)

    Chen, Wei-Yu; Lin, Chia-Jung; Ju, Yun-Ru; Tsai, Jeng-Wei; Liao, Chung-Min

    2012-11-01

    The impact of environmentally pulsed metal exposure on population dynamics of aquatic organisms remains poorly understood and highly unpredictable. The purpose of our study was to link a dynamic energy budget model to a toxicokinetic/toxicodynamic (TK/TD). We used the model to investigate tilapia population dynamics in response to pulsed waterborne copper (Cu) assessed with available empirical data. We mechanistically linked the acute and chronic bioassays of pulsed waterborne Cu at the scale of individuals to tilapia populations to capture the interaction between environment and population growth and reproduction. A three-stage matrix population model of larva-juvenile-adult was used to project offspring production through two generations. The estimated median population growth rate (λ) decreased from 1.0419 to 0.9991 under pulsed Cu activities ranging from 1.6 to 2.0 μg L(-1). Our results revealed that the influence on λ was predominately due to changes in the adult survival and larval survival and growth functions. We found that pulsed timing has potential impacts on physiological responses and population abundance. Our study indicated that increasing time intervals between first and second pulses decreased mortality and growth inhibition of tilapia populations, indicating that during long pulsed intervals tilapia may have enough time to recover. Our study concluded that the bioenergetics-based matrix population methodology could be employed in a life-cycle toxicity assessment framework to explore the effect of stage-specific mode-of-actions in population response to pulsed contaminants.

  13. Genetic diversity among food-borne and waterborne norovirus strains causing outbreaks in Sweden.

    Science.gov (United States)

    Lysén, Maria; Thorhagen, Margareta; Brytting, Maria; Hjertqvist, Marika; Andersson, Yvonne; Hedlund, Kjell-Olof

    2009-08-01

    A total of 101 food-borne and waterborne outbreaks that were caused by norovirus and that resulted in more than 4,100 cases of illness were reported to the Swedish Institute for Infectious Disease Control from January 2002 to December 2006. Sequence and epidemiological data for isolates from 73 outbreaks were analyzed. In contrast to health care-related outbreaks, no clear seasonality could be observed. Sequence analysis showed a high degree of genetic variation among the noroviruses detected. Genogroup II (GII) viruses were detected in 70% of the outbreaks, and of those strains, strains of GII.4 were the most prevalent and were detected in 25% of all outbreaks. The GII.4 variants detected in global outbreaks in health care settings during 2002, 2004, and 2006 were also found in the food-borne outbreaks. GI strains totally dominated as the cause of water-related (drinking and recreational water) outbreaks and were found in 12 of 13 outbreaks. In 14 outbreaks, there were discrepancies among the polymerase and capsid genotype results. In four outbreaks, the polymerase of the recombinant GII.b virus occurred together with the GII.1 or GII.3 capsids, while the GII.7 polymerase occurred together with the GII.6 and GII.7 capsids. Mixed infections were observed in six outbreaks; four of these were due to contaminated water, and two were due to imported frozen berries. Contaminated food and water serve as important reservoirs for noroviruses. The high degree of genetic diversity found among norovirus strains causing food-borne and waterborne infections stresses the importance of the use of broad reaction detection methods when such outbreaks are investigated.

  14. Reduced infectivity of waterborne viable but nonculturable Helicobacter pylori strain SS1 in mice.

    Science.gov (United States)

    Boehnke, Kevin F; Eaton, Kathryn A; Fontaine, Clinton; Brewster, Rebecca; Wu, Jianfeng; Eisenberg, Joseph N S; Valdivieso, Manuel; Baker, Laurence H; Xi, Chuanwu

    2017-08-01

    Helicobacter pylori infection has been consistently associated with lack of access to clean water and proper sanitation, but no studies have demonstrated that the transmission of viable but nonculturable (VBNC) H. pylori can occur from drinking contaminated water. In this study, we used a laboratory mouse model to test whether waterborne VBNCH. pylori could cause gastric infection. We performed five mouse experiments to assess the infectivity of VBNCH. pylori in various exposure scenarios. VBNC viability was examined using Live/Dead staining and Biolog phenotype metabolism arrays. High doses of VBNCH. pylori in water were chosen to test the "worst-case" scenario for different periods of time. One experiment also investigated the infectious capabilities of VBNC SS1 using gavage. Further, immunocompromised mice were exposed to examine infectivity among potentially vulnerable groups. After exposure, mice were euthanized and their stomachs were examined for H. pylori infection using culture and PCR methodology. VBNC cells were membrane intact and retained metabolic activity. Mice exposed to VBNCH. pylori via drinking water and gavage were not infected, despite the various exposure scenarios (immunocompromised, high doses) that might have permitted infection with VBNCH. pylori. The positive controls exposed to viable, culturable H. pylori did become infected. While other studies that have used viable, culturable SS1 via gavage or drinking water exposures to successfully infect mice, in our study, waterborne VBNC SS1 failed to colonize mice under all test conditions. Future studies could examine different H. pylori strains in similar exposure scenarios to compare the relative infectivity of the VBNC vs the viable, culturable state, which would help inform future risk assessments of H. pylori in water. © 2017 The Authors. Helicobacter Published by John Wiley & Sons Ltd.

  15. Hydroclimatic drivers, Water-borne Diseases, and Population Vulnerability in Bengal Delta

    Science.gov (United States)

    Akanda, A. S.; Jutla, A. S.

    2012-04-01

    Water-borne diarrheal disease outbreaks in the Bengal Delta region, such as cholera, rotavirus, and dysentery, show distinct seasonal peaks and spatial signatures in their origin and progression. However, the mechanisms behind these seasonal phenomena, especially the role of regional climatic and hydrologic processes behind the disease outbreaks, are not fully understood. Overall diarrheal disease prevalence and the population vulnerability to transmission mechanisms thus remain severely underestimated. Recent findings suggest that diarrheal incidence in the spring is strongly associated with scarcity of freshwater flow volumes, while the abundance of water in monsoon show strong positive correlation with autumn diarrheal burden. The role of large-scale ocean-atmospheric processes that tend to modulate meteorological, hydrological, and environmental conditions over large regions and the effects on the ecological states conducive to the vectors and triggers of diarrheal outbreaks over large geographic regions are not well understood. We take a large scale approach to conduct detailed diagnostic analyses of a range of climate, hydrological, and ecosystem variables to investigate their links to outbreaks, occurrence, and transmission of the most prevalent water-borne diarrheal diseases. We employ satellite remote sensing data products to track coastal ecosystems and plankton processes related to cholera outbreaks. In addition, we investigate the effect of large scale hydroclimatic extremes (e.g., droughts and floods, El Nino) to identify how diarrheal transmission and epidemic outbreaks are most likely to respond to shifts in climatic, hydrologic, and ecological changes over coming decades. We argue that controlling diarrheal disease burden will require an integrated predictive surveillance approach - a combination of prediction and prevention - with recent advances in climate-based predictive capabilities and demonstrated successes in primary and tertiary prevention

  16. Progression of the load of waterborne and intestinal parasitic diseases in the State of Amazonas

    Directory of Open Access Journals (Sweden)

    Marilaine Martins

    2015-06-01

    Full Text Available In the State of Amazonas, Brazil, urban expansion together with precarious basic sanitation conditions and human settlement on river banks has contributed to the persistence of waterborne and intestinal parasitic diseases. Time series of the recorded cases of cholera, typhoid fever, hepatitis A and leptospirosis are described, using data from different levels of the surveillance systems. The sources for intestinal parasitosis prevalence data (non-compulsory reporting in Brazil were Medical Literature Analysis and Retrieval System Online (MEDLINE, Literatura Latino-Americana (LILACS and the annals of major scientific meetings. Relevant papers and abstracts in all languages were accessed by two independent reviewers. The references cited by each relevant paper were scrutinized to locate additional papers. Despite its initial dissemination across the entire State of Amazonas, cholera was controlled in 1998. The magnitude of typhoid fever has decreased; however, a pattern characterized by eventual outbreaks still remains. Leptospirosis is an increasing cause of concern in association with the annual floods. The overall prevalence of intestinal parasites is high regardless of the municipality and the characteristics of areas and populations. The incidence of hepatitis A has decreased over the past decade. A comparison of older and recent surveys shows that the prevalence of intestinal parasitic diseases has remained constant. The load of waterborne and intestinal parasitic diseases ranks high among the health problems present in the State of Amazonas. Interventions aiming at basic sanitation and vaccination for hepatitis A were formulated and implemented, but assessment of their effectiveness in the targeted populations is still needed.

  17. Preparation and Property of Water-Borne Polyurethane Emulsions with High Surface Activity%高表面活性的水性聚氨酯乳液的制备及性能

    Institute of Scientific and Technical Information of China (English)

    林东恩; 杜闪闪; 潘耀宗

    2012-01-01

    以甲苯二异氰酸酯(TDI)、嵌段聚醚二醇PE6100以及聚醚胺ED-2003为原料,采用自乳化法合成了固含量40%的非离子型水性聚氨酯(WPU),通过红外光谱(FT-IR)对产物的结构进行了分析,并对产物的粒径、流变性能、表面张力、临界胶束浓度(CMC)进行了研究,结果表明,得到的WPU具有一定的触变性,平均粒径大多为100nm~400nm,在1g/L的浓度时水溶液的表面张力不超过37mN/m,具有较好的降低水溶液表面张力的能力。%Using toluene diiosocynate(TDI),polyether glycol PE6100 and polyetheramine ED-2003 as raw materials,a kind of nonionic water-borne polyurethane emulsions (WPU) was synthesized by the acetone method with solid content about 40%.Their structures were characterized by Fourier transform infrared spectrum analysis.The particle size,viscosity and surface activity,including surface tension,critical micelle concentration(CMC) in the aqueous solution were investigated.The results show that these water-borne polyurethane emulsions with particle sizes between 100nm and 400nm exhibit rheology behavior and excellent surface activity,most surface tension of these emulsions is less than 37 mN/m at concentration of 1 g/L.

  18. A-Salivary antibody responses as an indicator of waterborne infections: Pilot community study before and after installation of UV treatment

    Science.gov (United States)

    This ongoing project involves the development, validation and pilot application of a multiplex immunoassay based on Luminex microsphere technology to measure salivary antibody responses to the potentially-waterborne pathogens, noroviruses (Norwalk, VA387 and VA207), rotaviruses, ...

  19. A Modified EPA Method 1623 that Uses Tangential Flow Hollow-Fiber Ultrafiltration and Heat Dissociation Steps to Detect Waterborne Cryptosporidum and Giardia spp.

    Science.gov (United States)

    This protocol describes the use of a tangential flow hollow-fiber ultrafiltration sample concentration system and a heat dissociation as alternative steps for the detection of waterborne Cryptosporidium and Giardia species using EPA Method 1623.

  20. Presentation from 2016 STAR Tribal Research Meeting: Water, Our Voice to the Future: Climate Change Adaptation and Waterborne Disease Prevention on the Crow Reservation

    Science.gov (United States)

    This presentation, Water, Our Voice to the Future: Climate Change Adaptation and Waterborne Disease Prevention on the Crow Reservation, was given at the 2016 STAR Tribal Research Meeting held on Sept. 20-21, 2016.

  1. Research and Application of Waterborne Polyurethane%水性聚氨酯的研究现状及其应用

    Institute of Scientific and Technical Information of China (English)

    周学嘉; 胡啸林

    2011-01-01

    简要介绍了国内外对于水性聚氨酯的研究情况,水性聚氨酯的合成方法及其改性方法,概述了水性聚氨酯在纺织行业中的应用,指出水性聚氨酯将朝着环保、经济、低毒的方向发展。%The research situation of waterborne polyurethane at home and aborad,and synthesis and modified method of waterborne polyurethane were introduced briefly,and the application of waterborne polyurethane in textile was summarized.It pointed out that environmental,economy and low toxicity would be the future direction of the research of waterborne polyurethane.

  2. 羟丙基封端聚硅氧烷改性水性聚氨酯的制备及其性能研究%Study on preparation and application of waterborne polyurethane modified with hydroxypropyl polysiloxane

    Institute of Scientific and Technical Information of China (English)

    洪国沈; 吴明华; 高笑飞

    2015-01-01

    The waterborne polyurethane emulsion modified with hydroxypropyl polysiloxane (HP- PDMS) was prepared with isophorone di socyanate (IPDI) and polyether (N210) as raw materials, and HP- PDMS in⁃stead of part of N210, and the modified polyurethane was applied to coat the polyester fabric. The effect of the dosage of HP- PDMS on the properties of emulsion and its film was investigated, and the application prop⁃erties of the coated fabrics were tested. The results showed that as the dosage of HP- PDMS increased, the particle size of the emulsion increased, the stability of the emulsion decreased, the water contact angle of the film increased, water absorption rate of the film decreased; when the dosage of HP- PDMS was 6%, the sta⁃bility of the emulsion was good, the water contact angle of the film was 106.2° and the water absorption of the film was 32.49%. Compared with the unmodified waterborne polyurethane coated polyester fabric, the soft⁃ness and the hydrostatic pressure of the fabric coated with modified waterborne polyurethane were improved. Compared with fabric coated with polyether- polysiloxane modified waterborne polyurethane, the hydrostatic pressure and the water contact angle of the fabric coated with waterborne polyurethane emulsion modified with hydroxypropyl polysiloxane was improved, especial y water contact angle increased significantly, could reached 136.1°.%以异佛尔酮二异氰酸酯(IPDI)与聚醚(N210)为原料,采用自制羟丙基封端聚硅氧烷(HP-PDMS)替代部分聚醚(N210),制备羟丙基封端聚硅氧烷改性水性聚氨酯乳液,并用于涤纶织物涂层整理.研究改性剂HP-PDMS用量对乳液及胶膜性能的影响,测试涂层织物的应用性能.结果表明:随着HP-PDMS用量的增加,乳液粒径变大,稳定性变差,胶膜水接触角变大,吸水率变小.HP-PDMS用量为6%时,乳液稳定,胶膜水接触角为106.2°,吸水率为32.49%.与未改性的聚氨酯涂层织物相比

  3. Controllo del rischio clinico waterborne: modello di applicazione della metodologia Water Safety Plan in un’Azienda Ospedaliera

    OpenAIRE

    Congiu, Margherita

    2011-01-01

    The aim of this work is to apply the Water Safety Plan – the effective methodology for waterborne risk management in waterworks (WHO) – to hospital settings, such as those in the AOU of Sassari. WSP was applied to an hospital within the AOU, to control the waterborne risk from Legionella and Pseudomonas. The Control Plan was draft, team inspections, meetings, water samples were performed (Legionella, Ps.aeruginosa, CRAL, T) and organizational/operative information were taken. The following...

  4. 纳米材料改性水性聚氨酯的研究进展%Research progress of waterborne polyurethane modified with nano materials

    Institute of Scientific and Technical Information of China (English)

    张瑾; 马咏梅; 安招鹏

    2015-01-01

    综述了纳米材料改性水性聚氨酯几种常用方法的特点和研究进展,指出了纳米材料改性水性聚氨酯存在的问题。%Several commonly used methods and recent research progress of the nano materials in modified waterborne polyurethane were reviewed. And the existing questions for waterborne polyurethane modified with the nano materials were pointed out.

  5. 新型水性丙烯酸聚氨酯涂料的制备%Preparation of Novel Waterborne Acrylic Polyurethane Coatings

    Institute of Scientific and Technical Information of China (English)

    霍春会; 刘宪文; 薛丹; 徐涛

    2016-01-01

    Two-component waterborne polyurethane topcoat with high gloss and good durability was prepared by waterborne acrylic dispersant and waterborne isocyanate curing agent as main iflm building materials. The adding of varying waterborne hydroxyl acrylic dispersants, waterborne polyisocyanate, dispersion process, and additives on the properties of waterborne polyurethane dispersants were investigated. The prepared environmentally friendly coatings had good appearance, gloss retention and color retention.%以水性丙烯酸分散体和水性异氰酸酯固化剂为主要成膜物质制备了双组分水性聚氨酯高光耐候面漆,并讨论了不同水性羟基丙烯酸分散体、水性多异氰酸酯的配比及其分散工艺、不同助剂对水性聚氨酯分散体性能的影响。制备了一种具有优异装饰性和保光保色性的双组分水性丙烯酸聚氨酯环境友好型工业涂料。

  6. Widespread waterborne pollution in central Swedish lakes and the Baltic Sea from pre-industrial mining and metallurgy.

    Science.gov (United States)

    Bindler, Richard; Renberg, Ingemar; Rydberg, Johan; Andrén, Thomas

    2009-07-01

    Metal pollution is viewed as a modern problem that began in the 19th century and accelerated through the 20th century; however, in many parts of the globe this view is wrong. Here, we studied past waterborne metal pollution in lake sediments from the Bergslagen region in central Sweden, one of many historically important mining regions in Europe. With a focus on lead (including isotopes), we trace mining impacts from a local scale, through a 120-km-long river system draining into Mälaren--Sweden's third largest lake, and finally also the Baltic Sea. Comparison of sediment and peat records shows that pollution from Swedish mining was largely waterborne and that atmospheric deposition was dominated by long-range transport from other regions. Swedish ore lead is detectable from the 10th century, but the greatest impact occurred during the 16th-18th centuries with improvements occurring over recent centuries, i.e., historical pollution > modern industrial pollution.

  7. Coatings prepared from waterborne polyurethane dispersions obtained with polycarbonates of 1,6-hexanediol of different molecular weights

    OpenAIRE

    García Pacios, Vanesa; Jofre-Reche, José Antonio; Costa, Víctor; Colera, Manuel; Martín-Martínez, José Miguel

    2013-01-01

    Waterborne polyurethane dispersions (PUDs) were synthesized with polycarbonates of 1,6-hexanediol of different molecular weight (500–3000 Da) and their properties, adhesion (Hatch adhesion) and coatings on stainless steel properties (Pencil hardness, Persoz hardness, gloss at 60°, chemical resistance, yellowness index) were characterized. The hatch adhesion of the polyurethane coatings to stainless steel was very good and decreased slightly by increasing the molecular weight of the polycarbon...

  8. The Influence of Drinking Water Access on the Occurrence of Water-borne Diseases (Diarrhea and Typhoid)

    OpenAIRE

    Khadijah Azhar; Ika Dharmayanti; Athena Anwar

    2015-01-01

    Background: Poor and inadequate drinking water supply are the cause of the high occurrence of water-borne diseases,such as diarrhea and typhoid. These diseases often caused an outbreak among the citizens. This article was a furtheranalysis of data obtained from Basic Health Research (Riskesdas) in 2007 with the aim to figure out the influence of drinkingwater access against the occurrence of diarrhea and typhoid. Methods: the used samples were taken from all samples ofthe 2007 Riskesdas, whic...

  9. Coatings prepared from waterborne polyurethane dispersions obtained with polycarbonates of 1,6-hexanediol of different molecular weights

    OpenAIRE

    García Pacios, Vanesa; Jofre-Reche, José Antonio; Costa, Víctor; Colera, Manuel; Martín-Martínez, José Miguel

    2013-01-01

    Waterborne polyurethane dispersions (PUDs) were synthesized with polycarbonates of 1,6-hexanediol of different molecular weight (500–3000 Da) and their properties, adhesion (Hatch adhesion) and coatings on stainless steel properties (Pencil hardness, Persoz hardness, gloss at 60°, chemical resistance, yellowness index) were characterized. The hatch adhesion of the polyurethane coatings to stainless steel was very good and decreased slightly by increasing the molecular weight of the polycarbon...

  10. Thermal post-treatment alters nutrient release from a controlled-release fertilizer coated with a waterborne polymer

    Science.gov (United States)

    Zhou, Zijun; Du, Changwen; Li, Ting; Shen, Yazhen; Zhou, Jianmin

    2015-09-01

    Controlled-release fertilizers (CRF) use a controlled-release technology to enhance the nutrient use efficiency of crops. Many factors affect the release of nutrients from the waterborne polymer-coated CRF, but the effects of thermal post-treatments remain unclear. In this study, a waterborne polyacrylate-coated CRF was post-treated at different temperatures (30 °C, 60 °C, and 80 °C) and durations (2, 4, 8, 12, and 24 h) after being developed in the Wurster fluidized bed. To characterize the polyacrylate membrane, and hence to analyze the mechanism of nutrient release, Fourier transform mid-infrared spectroscopy, scanning electron microscopy, and atomic force microscopy were employed. The nutrient-release model of CRF post-treated at 30 °C was the inverse “L” curve, but an increased duration of the post-treatment had no effect. The nutrient-release model was “S” curve and nutrient-release period was enhanced at higher post-treatment temperatures, and increased post-treatment duration lengthened slowed nutrient release due to a more compact membrane and a smoother membrane surface as well as a promoted crosslinking action. CRF equipped with specified nutrient-release behaviors can be achieved by optimizing the thermal post-treatment parameters, which can contribute to the development and application of waterborne polymer-coated CRF and controlled-release technologies.

  11. 改性水性聚氨酯的研究进展%Review on modified waterborne polyurethane

    Institute of Scientific and Technical Information of China (English)

    任清刚; 唐敏锋; 吴伟卿; 李海银; 谢记桃

    2013-01-01

    The modification methods of waterborne polyurethane were summarized with acrylates,epoxy resins,silicone,organic fluoride and nano materials.Several optical modification methods were briefly introduced.The advantages and defects of these modification methods were pointed.The influences of modification on thermal stability,mechanical properties and other properties of waterborne polyurethane were discussed.Moreover,the future developments of waterborne polyurethane were also prospected.%通过丙烯酸酯、环氧树脂、有机硅、有机氟和纳米材料对水性聚氨酯进行改性是水性聚氨酯改性研究的重点。简述了几种较典型的改性方法,指出了不同改性技术的优势与不足以及改性对产品力学性能、热稳定性等的影响。展望了水性聚氨酯的未来发展方向。

  12. 水性聚氨酯改性研究进展%Progress in the Modification of Waterborne Polyurethane

    Institute of Scientific and Technical Information of China (English)

    徐廷旺; 唐克华; 袁才登

    2011-01-01

    单一的水性聚氨酯存在粘结性能差,干燥速度慢,耐水性和耐候性差等不足,因而必须对水性聚氨酯进行适当的改性,以提高其应用性能.本文综述了目前国内外水性聚氨酯的基本改性方法:交联改性、丙烯酸酯改性、环氧树脂改性、有机硅改性以及其他改性等,同时展望了水性聚氨酯改性研究的发展趋势.%The waterborne polyurethane has low binding strength,drying speed,water-and weather-resistance;therefore,it is necessary to modify the waterborne polyurethane to improve its function.In this paper,the techniques and methods for the modification of the waterborne polyurethane,such as the modification by cross linking,by polyacrylates,by epoxy,by organic silicone and other materials,are summarized.And the growing trend of the research is also proposed.

  13. Spatially explicit models, generalized reproduction numbers and the prediction of patterns of waterborne disease

    Science.gov (United States)

    Rinaldo, A.; Gatto, M.; Mari, L.; Casagrandi, R.; Righetto, L.; Bertuzzo, E.; Rodriguez-Iturbe, I.

    2012-12-01

    Metacommunity and individual-based theoretical models are studied in the context of the spreading of infections of water-borne diseases along the ecological corridors defined by river basins and networks of human mobility. The overarching claim is that mathematical models can indeed provide predictive insight into the course of an ongoing epidemic, potentially aiding real-time emergency management in allocating health care resources and by anticipating the impact of alternative interventions. To support the claim, we examine the ex-post reliability of published predictions of the 2010-2011 Haiti cholera outbreak from four independent modeling studies that appeared almost simultaneously during the unfolding epidemic. For each modeled epidemic trajectory, it is assessed how well predictions reproduced the observed spatial and temporal features of the outbreak to date. The impact of different approaches is considered to the modeling of the spatial spread of V. cholera, the mechanics of cholera transmission and in accounting for the dynamics of susceptible and infected individuals within different local human communities. A generalized model for Haitian epidemic cholera and the related uncertainty is thus constructed and applied to the year-long dataset of reported cases now available. Specific emphasis will be dedicated to models of human mobility, a fundamental infection mechanism. Lessons learned and open issues are discussed and placed in perspective, supporting the conclusion that, despite differences in methods that can be tested through model-guided field validation, mathematical modeling of large-scale outbreaks emerges as an essential component of future cholera epidemic control. Although explicit spatial modeling is made routinely possible by widespread data mapping of hydrology, transportation infrastructure, population distribution, and sanitation, the precise condition under which a waterborne disease epidemic can start in a spatially explicit setting is

  14. TECHNOLOGY EVALUATION FOR WATERBORNE MERCURY REMOVAL AT THE Y12 NATIONAL SECURITY COMPLEX

    Energy Technology Data Exchange (ETDEWEB)

    He, Feng [ORNL; Liang, Liyuan [ORNL; Miller, Carrie L [ORNL

    2011-01-01

    The Hg-contaminated processing water produced at Y-12 facility is discharged through the storm drain system, merged at Outfall 200, and then discharged to EFPC. Most of the baseflow mercury at Outfall 200 arises from a small number of short sections of storm drain. This report discusses the waterborne mercury treatment technologies to decrease mercury loading to the surface water of EFPC at Y-12 NSC. We reviewed current available waterborne Hg treatment technologies based on the specific conditions of Y-12 and identified two possible options: SnCl2 reduction coupled with air stripping (SnCl2/air stripping) and sorption. The ORNL 2008 and 2009 field studies suggested that SnCl2/air stripping has the capability to remove waterborne mercury with efficiency higher than 90% at Outfall 200. To achieve this goal, dechlorination (i.e., removing residual chlorine from water) using dechlorinating agents such as thiosulfate has to be performed before the reduction. It is unclear whether or not SnCl2/air stripping can reduce the mercury concentration from ~1000 ng/L to 51 ng/L at a full-scale operation. Therefore, a pilot test is a logical step before a full-scale design to answer questions such as Hg removal efficiency, selection of dechlorinating agents, and so on. The major advantages of the SnCl2/air stripping system are: (1) expected low cost at high flow (e.g., the flow at Outfall 200); and (2) production of minimum secondary waste. However, there are many environmental uncertainties associated with this technology by introducing tin to EFPC ecosystem, for example tin methylation causing abiotic Hg methylation, which should be addressed before a full-scale implementation. Mercury adsorption by granular activated carbon (GAC) is a proven technology for treating Hg at Y-12. The ONRL 2010 lab sorption studies suggest that thiol-based resins hold the promise to combine with GAC to form a more cost-effective treatment system. To achieve a treatment goal of 51 ng/L at Outfall

  15. Hydrologic, land cover, and seasonal patterns of waterborne pathogens in Great Lakes tributaries

    Science.gov (United States)

    Lenaker, Peter L.; Corsi, Steven; Borchardt, Mark A.; Spencer, Susan K.; Baldwin, Austin K.; Lutz, Michelle A.

    2017-01-01

    Great Lakes tributaries are known to deliver waterborne pathogens from a host of sources. To examine the hydrologic, land cover, and seasonal patterns of waterborne pathogens (i.e. protozoa (2), pathogenic bacteria (4) human viruses, (8) and bovine viruses (8)) eight rivers were monitored in the Great Lakes Basin over 29 months from February 2011 to June 2013. Sampling locations represented a wide variety of land cover classes from urban to agriculture to forest. A custom automated pathogen sampler was deployed at eight sampling locations which provided unattended, flow-weighted, large-volume (120–1630 L) sampling. Human and bovine viruses and pathogenic bacteria were detected by real-time qPCR in 16%, 14%, and 1.4% of 290 samples collected while protozoa were never detected. The most frequently detected pathogens were: bovine polyomavirus (11%), and human adenovirus C, D, F (9%). Human and bovine viruses were present in 16.9% and 14.8% of runoff-event samples (n = 189) resulting from precipitation and snowmelt, and 13.9% and 12.9% of low-flow samples (n = 101), respectively, indicating multiple delivery mechanisms could be influential. Data indicated human and bovine virus prevalence was different depending on land cover within the watershed. Occurrence, concentration, and flux of human viruses were greatest in samples from the three sampling locations with greater than 25% urban influence than those with less than 25% urban influence. Similarly, occurrence, concentration, and flux of bovine viruses were greatest in samples from the two sampling locations with greater than 50 cattle/km2 than those with less than 50 cattle/km2. In seasonal analysis, human and bovine viruses occurred more frequently in spring and winter seasons than during the fall and summer. Concentration, occurrence, and flux in the context of hydrologic condition, seasonality, and land use must be considered for each watershed individually to develop effective watershed management

  16. Hydrologic, land cover, and seasonal patterns of waterborne pathogens in Great Lakes tributaries.

    Science.gov (United States)

    Lenaker, P L; Corsi, S R; Borchardt, M A; Spencer, S K; Baldwin, A K; Lutz, M A

    2017-04-15

    Great Lakes tributaries are known to deliver waterborne pathogens from a host of sources. To examine the hydrologic, land cover, and seasonal patterns of waterborne pathogens (i.e. protozoa (2), pathogenic bacteria (4) human viruses, (8) and bovine viruses (8)) eight rivers were monitored in the Great Lakes Basin over 29 months from February 2011 to June 2013. Sampling locations represented a wide variety of land cover classes from urban to agriculture to forest. A custom automated pathogen sampler was deployed at eight sampling locations which provided unattended, flow-weighted, large-volume (120-1630 L) sampling. Human and bovine viruses and pathogenic bacteria were detected by real-time qPCR in 16%, 14%, and 1.4% of 290 samples collected while protozoa were never detected. The most frequently detected pathogens were: bovine polyomavirus (11%), and human adenovirus C, D, F (9%). Human and bovine viruses were present in 16.9% and 14.8% of runoff-event samples (n = 189) resulting from precipitation and snowmelt, and 13.9% and 12.9% of low-flow samples (n = 101), respectively, indicating multiple delivery mechanisms could be influential. Data indicated human and bovine virus prevalence was different depending on land cover within the watershed. Occurrence, concentration, and flux of human viruses were greatest in samples from the three sampling locations with greater than 25% urban influence than those with less than 25% urban influence. Similarly, occurrence, concentration, and flux of bovine viruses were greatest in samples from the two sampling locations with greater than 50 cattle/km(2) than those with less than 50 cattle/km(2). In seasonal analysis, human and bovine viruses occurred more frequently in spring and winter seasons than during the fall and summer. Concentration, occurrence, and flux in the context of hydrologic condition, seasonality, and land use must be considered for each watershed individually to develop effective watershed management

  17. Preparation and Characterization of Two-component Waterborne Polyurethane Comprised of Water-soluble Acrylic Resin and HDI Biuret%水性双组份丙烯酸聚氨酯的合成与表征

    Institute of Scientific and Technical Information of China (English)

    周新华; 涂伟萍; 胡剑青

    2006-01-01

    A two-component waterborne polyurethane (2K-WPU) was prepared by mixing water-soluble acrylic resin and hexamethylene diisocyanate biuret, and then diluted for phase inversion with water. Compared with water-soluble acrylic resin, the phase inversion of 2K-WPU occurs at lower water content. It is indicated by TEM that 2K-WPU particles show a core-shell structure, in which HDI biuret is encapsulated by hydrophilic acrylic resin. 2K-WPU emulsion with HDI biuret has larger particle size and narrower distribution index, while for 2K-WPU emulsion with HDI isocyanurate, the latex not only has large particle size, but also has two-peak distribution. FTIR shows that the reaction between HDI biuret and acrylic resin can complete in 12h. In addition, studies on effect of composition of acrylic resin on pefformance of 2K-WPU show that narrowing the polar difference between water-soluble acrylic resin and HDI biuret and improving the miscibility of two components are the key to prepare the transparent and high gloss films with high crosslinking density.

  18. Assessment of Macro-Level Socioeconomic Factors That Impact Waterborne Diseases: The Case of Jordan

    Directory of Open Access Journals (Sweden)

    John M. Polimeni

    2016-11-01

    Full Text Available The Hashemite Kingdom of Jordan is an example of a country that suffers from high water scarcity. Additionally, due to the economic drivers in the country, such as phosphate and potash extraction and pharmaceutical production, the little fresh water that remains is generally polluted. The infrastructure, often antiquated in urban areas and non-existent in rural areas, also contributes to poor water conditions and to the spread of waterborne diseases. This paper examines the socioeconomic factors that contribute to diarrhea and hepatitis A on a macro level in Jordan and discusses the public-policies that government officials could use to abate those problems. Ordinary least squares time series models are used to understand the macro-level variables that impact the incidence of these diseases in Jordan. Public health expenditure has a significant impact on reducing their incidence. Furthermore, investment in sanitation facilities in rural regions is likely to reduce the number of cases of hepatitis A. Perhaps the most surprising outcome is that importation of goods and services likely results in a decrease in cases of hepatitis A. However, income has little impact on the incidence of diarrhea and hepatitis A.

  19. Comparative study on waterborne parasites between Malaysia and Thailand: A new insight.

    Science.gov (United States)

    Kumar, Thulasi; Onichandran, Subashini; Lim, Yvonne A L; Sawangjaroen, Nongyao; Ithoi, Init; Andiappan, Hemah; Salibay, Cristina C; Dungca, Julieta Z; Chye, Tan Tian; Sulaiman, Wan Y W; Ling Lau, Yee; Nissapatorn, Veeranoot

    2014-04-01

    This study investigated the distribution of parasites as main contaminants in water environments of peninsular Malaysia (October 2011-December 2011) and the southeastern coast of Thailand (June 2012). Sixty-four water samples, 33 from Malaysia and 31 from Thailand, of various water types were examined according to U.S. Environmental Protection Agency guidelines. Drinking or household water types from both countries were free from parasitic contamination. The recreational/environmental (except a swimming pool in Malaysia) and effluent water types from these two countries were contaminated with waterborne parasites: Giardia (0.04-4 cysts/L), Cryptosporidium (0.06-2.33 oocysts/L), hookworm (6.67-350 ova/L), Ascaris (0.33-33.33 ova/L), and Schistosoma (9.25-13.33 ova/L). The most contaminated sites were recreational lake garden 3 in Malaysia and river 2 in Thailand. Higher concentrations of Giardia, Cryptosporidium, and hookworm were found in samples from Malaysia than in samples from Thailand. The presence of Giardia cysts showed a significant association with the presence of Cryptosporidium oocysts (P < 0.005).

  20. Synthesis and properties of waterborne polyurethane hydrogels for wound healing dressings.

    Science.gov (United States)

    Yoo, Hye-Jin; Kim, Han-Do

    2008-05-01

    To accomplish ideal wound healing dressing, a series of waterborne polyurethane (WBPU) hydrogels based on polyethylene glycol (PEG) were synthesized by polyaddition reaction in an emulsion system. The stable WBPU hydrogels which have remaining weight of above 85% were obtained. The effect of the soft segment (PEG) content on water absorbability of WBPU hydrogels was investigated. Water absorption % and equilibrium water content (%) of the WBPU hydrogel significantly increased in proportion to PEG content and the time of water-immersion. The maximum water absorption % and equilibrium water content (%) of WBPU hydrogels containing various PEG contents were in the range of 409-810% and 85-96%, respectively. The water vapor transmission rate of the WBPU hydrogels was found to be in the range of 1490-3118 g/m(2)/day. These results suggest that the WBPU hydrogels prepared in this study may have high potential as new wound dressing materials, which provide and maintain the adequate moist environment required to prevent scab formation and dehydration of the wound bed. By the wound healing evaluation using full-thickness rat model experiment, it was found that the wound covered with a typical WBPU hydrogel (HG-78 sample) was completely filled with new epithelium without any significant adverse reactions.

  1. Thermoset nanocomposites from two-component waterborne polyurethanes and cellulose whiskers.

    Science.gov (United States)

    Wu, Guo-min; Chen, Jian; Huo, Shu-ping; Liu, Gui-feng; Kong, Zhen-wu

    2014-05-25

    We prepared thermoset nancomposites from biomass-based two-component waterborne polyurethane (2K-WPU) and cellulose namowhiskers (CNWs). Due to the formation of hydrogen bonds, the viscosity of 2K-WPU dispersion was found to be increased with the addition of CNWs. SEM images showed "sea-island structure" corresponding to the microphase separation between CNWs nano-filler and the 2K-WPU matrix. The α-relaxation temperature (Tα) and glass transition temperature (Tg) increased with the increase of CNWs content, which was due to the formation of a rigid CNWs nano-phase acting as crosslinking points in the 2K-WPU matrix. Mechanical properties from tensile test showed Young's modulus and tensile strength of 2K-WPU/CNWs nanocomposites were reinforced by the addition of CNWs. Thermo-stability of 2K-WPU/CNWs nanocomposites decreased slightly with the increase of CNWs content, which could be attributed to the increased thermal conductivity of the material after adding CNWs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Electromagnetic interference shielding performance of waterborne polyurethane composites filled with silver nanoparticles deposited on functionalized graphene

    Science.gov (United States)

    Lin, Sheng-Chi; Ma, Chen-Chi M.; Hsiao, Sheng-Tsung; Wang, Yu-Sheng; Yang, Chih-Yu; Liao, Wei-Hao; Li, Shin-Ming; Wang, Jeng-An; Cheng, Tzu-Yu; Lin, Chih-Wen; Yang, Ruey-Bin

    2016-11-01

    The objective of this study was to prepare an electromagnetic interference shielding material, waterborne polyurethane (WPU) filled with silver-nanoparticle-decorated functional reduced graphene oxide (Ag@FRGO). Functional reduced graphene oxide (FRGO) was functionalized through free-radical polymerization before chemical reduction, to prevent restacking and aggregation during the reduction. After the functionalization, the homogeneous dispersion of FRGO promoted the formation of conductive networks throughout the WPU matrix. To enhance the electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of the composites, silver nanoparticles (Ag NPs) were deposited on the FRGO surface. Subsequently, WPU composites were synthesized through the solution-mixing method. Their microstructure, morphology, electrical conductivity, and EMI SE were investigated, and the results showed that, among Ag@FRGO/WPU composites with different values for the weight ratio of Ag NPs to FRGO, the Ag@FRGO/WPU composite with 5 wt% FRGO and a weight ratio of Ag to NPs of 10:1 (10Ag@FRGO/WPU) exhibited the highest electrical conductivity (25.52 S/m) and an EMI SE of 35 dB in the frequency range of 8.2-12.4 GHz (X-band).

  3. Climate change and waterborne diarrhoea in northern India: impacts and adaptation strategies.

    Science.gov (United States)

    Moors, Eddy; Singh, Tanya; Siderius, Christian; Balakrishnan, Sneha; Mishra, Arabinda

    2013-12-01

    Although several studies show the vulnerability of human health to climate change, a clear comprehensive quantification of the increased health risks attributable to climate change is lacking. Even more complicated are assessments of adaptation measures for this sector. We discuss the impact of climate change on diarrhoea as a representative of a waterborne infectious disease affecting human health in the Ganges basin of northern India. A conceptual framework is presented for climate exposure response relationships based on studies from different countries, as empirical studies and appropriate epidemiological data sets for India are lacking. Four climate variables are included: temperature, increased/extreme precipitation, decreased precipitation/droughts and relative humidity. Applying the conceptual framework to the latest regional climate projections for northern India shows increases between present and future (2040s), varying spatially from no change to an increase of 21% in diarrhoea incidences, with 13.1% increase on average for the Ganges basin. We discuss three types of measures against diarrhoeal disease: reactive actions, preventive actions and national policy options. Preventive actions have the potential to counterbalance this expected increase. However, given the limited progress in reducing incidences over the past decade consorted actions and effective implementation and integration of existing policies are needed.

  4. Health effects of Acanthamoeba spp. and its potential for waterborne transmission.

    Science.gov (United States)

    Nwachuku, Nena; Gerba, Charles P

    2004-01-01

    Risk from Acanthamoeba keratitis is complex, depending upon the virulence of the particular strain, exposure, trauma, or other stress to the eye, and host immune response. Bacterial endosymbionts may also play a factor in the pathogenicity of Acanthamoeba. Which factor(s) may be the most important is not clear. The ability of the host to produce IgA antibodies in tears may be a significant factor. The immune response of the host is a significant risk factor for GAE infection. If so, then a certain subpopulation with an inability to produce IgA in the tears may be at greatest risk. There was no sufficient data on the occurrence or types of Acanthamoeba in tapwater in the U.S. Published work on amoebal presence in tapwater does not provide information on the type of treatment the water received or the level of residual chlorine. Assessment of the pathogenicity by cell culture and molecular methods of Acanthamoeba in tapwater would also be useful in the risk assessment process for drinking water. The possibility that Acanthamoeba spp. might serve as vectors for bacterial infections from water sources also should be explored. The bacterial endosymbionts include an interesting array of pathogens such as Vibrio cholerae and Legionella pneumophila, both of which are well recognized waterborne/water-based pathogens. Work is needed to determine if control of Acanthamoeba spp. is needed to control water-based pathogens in water supplies.

  5. PEGylated chitosan protected silver nanoparticles as water-borne coating for leather with antibacterial property.

    Science.gov (United States)

    Liu, Gongyan; Li, Kaijun; Luo, Quanqing; Wang, Haibo; Zhang, Zongcai

    2017-03-15

    Development of eco-labeled and effectively antibacterial coatings for final leather products has been desiderated both by industry and by consumers. Herein, PEGylated chitosan modified silver nanoparticles (PEG-g-CS@AgNPs) were prepared and characterized by UV-vis spectroscopy, transmission electron microscopy and dynamic light scattering. The antimicrobial activity of such silver nanoparticles was investigated against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus), exhibiting much lower minimum inhibitory concentration (MIC) than chitosan or PEG-g-CS. Water-borne coating was formed by immobilizing the PEG-g-CS@AgNPs onto the leather surface through the electrostatic interaction between amino groups of chitosan and carboxyl groups of leather collagen. Scanning electron microscopy and water contact angle were employed to study the coating's morphology and hydrophilicity, respectively. After coating, leather samples showed significantly high bactericidal efficiency with reusability after release of dead cells from the coating by simply water washing. The excellent antibacterial property of PEG-g-CS@AgNPs coating was ascribed to the combination of bacteria-resistance and bacteria-release by PEGylation, and dual bacteria-killing based on chitosan and Ag(+) release.

  6. Detection and quantification of waterborne microorganisms using an image cytometer based on angular spatial frequency processing

    CERN Document Server

    Pérez, Juan Miguel; Martínez, Pedro; Pruneri, Valerio

    2015-01-01

    We introduce a new image cytometer design for detection of very small particulate and demonstrate its capability in water analysis. The device is a compact microscope composed of off--the--shelf components, such as a light emitting diode (LED) source, a complementary metal--oxide--semiconductor (CMOS) image sensor, and a specific combination of optical lenses that allow, through an appropriate software, Fourier transform processing of the sample volume. Waterborne microorganisms, such as Escherichia coli (E. coli), Legionella pneumophila (L. pneumophila) and Phytoplankton, are detected by interrogating the volume sample either in a fluorescent or label-free mode, i.e. with or without fluorescein isothiocyanate (FITC) molecules attached to the micro-organisms, respectively. We achieve a sensitivity of 50 CFU/ml, which can be further increased to 0.2 CFU/ml by pre-concentrating an initial sample volume of 500 ml with an ad hoc fluidic system. We also prove the capability of the proposed image cytometer of diffe...

  7. Thermoset nanocomposites from waterborne bio-based epoxy resin and cellulose nanowhiskers.

    Science.gov (United States)

    Wu, Guo-min; Liu, Di; Liu, Gui-feng; Chen, Jian; Huo, Shu-ping; Kong, Zhen-wu

    2015-01-01

    Thermoset nanocomposites were prepared from a waterborne terpene-maleic ester type epoxy resin (WTME) and cellulose nanowhiskers (CNWs). The curing behaviors of WTME/CNWs nanocomposites were measured with rotational rheometer. The results show that the storage modulus (G') of WTME/CNWs nanocomposites increased with the increase of CNWs content. Observations by scanning electron microscopy (SEM) demonstrate that the incorporation of CNWs in WTME matrix caused microphase separation and destroyed the compactness of the matrix. This effect leads to the glass transition temperatures (Tg) of WTME/CNWs nanocomposites slightly decrease with the increase of CNWs content, which were confirmed by both DSC and DMA tests. The mechanical properties of WTME/CNWs nanocomposites were investigated by tensile testing. The Yong's modulus (E) and tensile strength (σb) of the nanocomposites were significantly reinforced by the addition of CNWs. These results indicate that CNWs exhibit excellent reinforcement effect on WTME matrix, due to the formation and increase of interfacial interaction by hydrogen bonds between CNWs nano-filler and the WTME matrix.

  8. The role of cellulose nanocrystals incorporation route in waterborne polyurethane for preparation of electrospun nanocomposites mats.

    Science.gov (United States)

    Santamaria-Echart, Arantzazu; Ugarte, Lorena; Gonzalez, Kizkitza; Martin, Loli; Irusta, Lourdes; Gonzalez, Alba; Corcuera, Maria Angeles; Eceiza, Arantxa

    2017-06-15

    Electrospinning offers the possibility of obtaining fibers mats from polymer solutions. The use of environmentally-friendly waterborne polyurethane (WBPU) allows obtaining electrospun polyurethane mats in water medium. Furthermore, the incorporation of water dispersible nanoentities, like renewable cellulose nanocrystals (CNC), is facilitated. Therefore, in this work, a WBPU was synthesized and CNC were isolated for preparing WBPU-CNC dispersions nanocomposites with 1 and 3wt% of CNC following both the classical mixing by sonication, and the innovative in-situ route. The dispersions were used for obtaining electrospun mats assisted by poly(ethylene oxide) (PEO) as polymer template. Moreover, the extraction of PEO with water resulted in continuous WBPU-CNC mats, showing different properties respect to WBPU-CNC mats containing PEO. The effective addition of CNC led to more defined cylindrical morphologies and the two alternative incorporation routes induced to different CNC dispositions in the matrix, which modified fibers diameters, and thus, mats final properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Fully glutathione degradable waterborne polyurethane nanocarriers: Preparation, redox-sensitivity, and triggered intracellular drug release.

    Science.gov (United States)

    Omrani, Ismail; Babanejad, Niloofar; Shendi, Hasan Kashef; Nabid, Mohammad Reza

    2017-01-01

    Polyurethanes are important class of biomaterials that are extensively used in medical devices. In spite of their easy synthesis, polyurethanes that are fully degradable in response to the intracellular reducing environment are less explored for controlled drug delivery. Herein, a novel glutathione degradable waterborne polyurethane (WPU) nanocarrier for redox triggered intracellular delivery of a model lipophilic anticancer drug, doxorubicin (DOX) is reported. The WPU was prepared from polyaddition reaction of isophorone diisocyanate (IPDI) and a novel linear polyester polyol involving disulfide linkage, disulfide labeled chain extender, dimethylolpropionic acid (DMPA) using dibutyltin dilaurate (DBTDL) as a catalyst. The resulting polyurethane self-assembles into nanocarrier in water. The dynamic light scattering (DLS) measurements and scanning electron microscope (SEM) revealed fast swelling and disruption of nanocarriers under an intracellular reduction-mimicking environment. The in vitro release studies showed that DOX was released in a controlled and redox-dependent manner. MTT assays showed that DOX-loaded WPU had a high in vitro antitumor activity in both HDF noncancer cells and MCF- 7 cancer cells. In addition, it is found that the blank WPU nanocarriers are nontoxic to HDF and MCF-7 cells even at a high concentration of 2mg/mL. Hence, nanocarriers based on disulfide labeled WPU have appeared as a new class of biocompatible and redox-degradable nanovehicle for efficient intracellular drug delivery. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Detection and quantification of virulent Aeromonas hydrophila in channel catfish tissues following waterborne challenge.

    Science.gov (United States)

    Zhang, Dunhua; Moreira, Gabriel S A; Shoemaker, Craig; Newton, Joseph C; Xu, De-Hai

    2016-05-01

    The aim of this study was to understand the pathogenesis of motile aeromonas septicemia caused by an emergent, high virulent Aeromonas hydrophila (vAh) in channel catfish, Ictalurus punctatus Adipose fin clipped catfish were challenged with vAh using a waterborne challenge method, and the distribution of vAh over a time course was detected and quantified using real-time polymerase chain reaction. The results showed that 77.8% of fish died within 48 h post challenge with mean day to death of 1.5 days. At 2 h post challenge, vAh (inferred from genomic DNA copies or genome equivalents) was detected in all external and internal tissues sampled. Gill had the highest vAh cells at 1 h post challenge. Spleen harbored the most vAh cells among internal organs at 4 h post challenge. The tissues/organs with most vAh cells detected at 8 h post challenge were adipose fin, blood, intestine, kidney and skin, while liver showed the highest vAh cells at 24 h post challenge. These results suggest that vAh was able to rapidly proliferate and spread, following wound infection, through the fish blood circulation system and cause mortality within 8-24 h.

  11. [Water-borne outbreak of Yersinia enterocolitica O8 due to a small scale water system].

    Science.gov (United States)

    Isobe, Junko; Kimata, Keiko; Shimizu, Miwako; Kanatani, Jun-ichi; Sata, Tetsutaro; Watahiki, Masanori

    2014-11-01

    A water-borne outbreak of Yersinia enterocolitica O:8 associated with a small-scale water system occurred during July-August 2011 in Toyama Prefecture, Japan. Escherichia coli was not detected in tap water from the small-scale water system. However, the maximum concentration of viable bacteria in the tap water was 700CFU/mL, which exceeds the legal standard for purity of tap water (100CFU/mL). Furthermore, Y. enterocolitica O8 was isolated from the tap water with the use of immunomagnetic beads prepared with anti-Y. enterocolitica O8 antibodies. Pulsed-field gel electrophoresis analysis identified 3 isolates from tap water and 5 isolates from 4 patient stool specimens as belonging to the outbreak strain. An epidemiological investigation revealed improper management of the residual chlorine concentration in the tap water. This is the first report of an outbreak of Y. enterocolitica due to tap water from a small-scale water system in Japan.

  12. Reduced swim performance and aerobic capacity in adult zebrafish exposed to waterborne selenite.

    Science.gov (United States)

    Massé, Anita J; Thomas, Jith K; Janz, David M

    2013-04-01

    Although dietary exposure of adult fish to organoselenium in contaminated aquatic ecosystems has been reported to bioaccumulate and cause larval deformities in offspring, subtle physiological effects produced through low level waterborne selenium exposure in fish such as swim performance and aerobic capacity have not been investigated. To evaluate potential effects of selenite on these responses, adult zebrafish (Danio rerio) were exposed to nominal aqueous concentrations of 0, 10 or 100 μg/L sodium selenite for 14 days. Upon completion of the exposure period, fish underwent two successive swim trials in a swim tunnel respirometer to determine critical swim speed (Ucrit), oxygen consumption (MO2), standard and active metabolic rates, aerobic scope (AS) and cost of transport (COT) followed by analysis of whole body triglyceride and glycogen concentrations. Selenite exposure had a significant negative effect on Ucrit and aerobic capacity. Active metabolic rates and AS significantly decreased in both selenite exposure groups after the second swim trial. No significant effect was observed in MO2, standard metabolic rate, COT, triglyceride and glycogen levels, or condition factor between groups. These results suggest that aqueous selenite exposure at environmentally relevant concentrations produces adverse effects on aerobic capacity that can diminish endurance and maximum swim speeds, which may lower fish survivability.

  13. Assessment of Macro-Level Socioeconomic Factors That Impact Waterborne Diseases: The Case of Jordan

    Science.gov (United States)

    Polimeni, John M.; Almalki, Ahmad; Iorgulescu, Raluca I.; Albu, Lucian-Liviu; Parker, Wendy M.; Chandrasekara, Ray

    2016-01-01

    The Hashemite Kingdom of Jordan is an example of a country that suffers from high water scarcity. Additionally, due to the economic drivers in the country, such as phosphate and potash extraction and pharmaceutical production, the little fresh water that remains is generally polluted. The infrastructure, often antiquated in urban areas and non-existent in rural areas, also contributes to poor water conditions and to the spread of waterborne diseases. This paper examines the socioeconomic factors that contribute to diarrhea and hepatitis A on a macro level in Jordan and discusses the public-policies that government officials could use to abate those problems. Ordinary least squares time series models are used to understand the macro-level variables that impact the incidence of these diseases in Jordan. Public health expenditure has a significant impact on reducing their incidence. Furthermore, investment in sanitation facilities in rural regions is likely to reduce the number of cases of hepatitis A. Perhaps the most surprising outcome is that importation of goods and services likely results in a decrease in cases of hepatitis A. However, income has little impact on the incidence of diarrhea and hepatitis A. PMID:27898017

  14. Various nanoparticle morphologies and surface properties of waterborne polyurethane controlled by water

    Science.gov (United States)

    Zhou, Xing; Fang, Changqing; Lei, Wanqing; Du, Jie; Huang, Tingyi; Li, Yan; Cheng, Youliang

    2016-09-01

    Water plays important roles in organic reactions such as polyurethane synthesis, and the aqueous solution environment affects polymer morphology and other properties. This paper focuses on the morphology and surface properties of waterborne polyurethane resulting from the organic reaction in water involving different forms (solid and liquid), temperatures and aqueous solutions. We provide evidence from TEM observations that the appearance of polyurethane nanoparticles in aqueous solutions presents diverse forms, including imperfect spheres, perfect spheres, perfect and homogenous spheres and tubes. Based on the results on FTIR, GPC, AFM and XRD experiments, we suggest that the shape of the nanoparticles may be decided by the crimp degree (i.e., the degree of polyurethane chains intertangling in the water environment) and order degree, which are determined by the molecular weight (Mn) and hydrogen bonds. Meanwhile, solid water and high-temperature water can both reduce hard segments that gather on the polyurethane film surface to reduce hydrophilic groups and produce a soft surface. Our findings show that water may play key roles in aqueous polymer formation and bring order to molecular chains.

  15. Assessment of Macro-Level Socioeconomic Factors That Impact Waterborne Diseases: The Case of Jordan.

    Science.gov (United States)

    Polimeni, John M; Almalki, Ahmad; Iorgulescu, Raluca I; Albu, Lucian-Liviu; Parker, Wendy M; Chandrasekara, Ray

    2016-11-25

    The Hashemite Kingdom of Jordan is an example of a country that suffers from high water scarcity. Additionally, due to the economic drivers in the country, such as phosphate and potash extraction and pharmaceutical production, the little fresh water that remains is generally polluted. The infrastructure, often antiquated in urban areas and non-existent in rural areas, also contributes to poor water conditions and to the spread of waterborne diseases. This paper examines the socioeconomic factors that contribute to diarrhea and hepatitis A on a macro level in Jordan and discusses the public-policies that government officials could use to abate those problems. Ordinary least squares time series models are used to understand the macro-level variables that impact the incidence of these diseases in Jordan. Public health expenditure has a significant impact on reducing their incidence. Furthermore, investment in sanitation facilities in rural regions is likely to reduce the number of cases of hepatitis A. Perhaps the most surprising outcome is that importation of goods and services likely results in a decrease in cases of hepatitis A. However, income has little impact on the incidence of diarrhea and hepatitis A.

  16. Research Progress on Waterborne Polyurethane Synthetic Leather Surface Treatment Agent%水性聚氨酯合成革表面处理剂研究进展

    Institute of Scientific and Technical Information of China (English)

    陈新; 杨明华; 沈秋仙

    2015-01-01

    水性聚氨酯具有环保、无毒等特性,将水性聚氨酯应用于合成革涂饰剂可以消除溶剂型合成革处理剂的环境污染问题。本文从合成革表面处理剂的应用现状、合成革用高物性水性聚氨酯研发现状、合成革用水性聚氨酯助剂以及水性聚氨酯合成革表面处理剂品种等几方面进行分析和探讨,指出水性聚氨酯合成革表面处理剂的研发方向。%With environmental and non-toxic characteristics , waterborne polyurethane applied to synthetic leather finishing agent can eliminate the environmental pollution problem of the solvent synthetic leather treatment agent .The present situation of the application of synthetic leather surface treatment agent , the present situation of research and development of waterborne polyurethane with high physical properties for synthetic leather , waterborne polyurethane additives for synthetic leather and waterborne polyurethane leather surface treating agent varieties were analyzed and discussed , and the direction of research and development of waterborne polyurethane synthetic leather surface treatment agent was pointed out.

  17. Preparation of raspberry-like PMMA/SiO2 nanocomposite particles

    Institute of Scientific and Technical Information of China (English)

    Chen Min; You Bo; Zhou Shuxue; Wu Limin

    2006-01-01

    Water-borne raspberry-like PMMA/SiO2 nanocom-posite particles were prepared via free radical copolymerization of methyl methacrylate (MMA) with 1-vinylimidazole (1-VID) in the presence of ultrafine aqueous silica sols.The acid-base interaction between hydroxyl groups (acidic) of silica surfaces and amino groups (basic) of 1-VID was strong enough for promoting the formation of long-standing stable PMMA/SiO2 nanocomposite particles when 10 mol% or more 1-VID as auxiliary monomer was used.The average particle sizes and the silica contents of the nanocomposite particles were in the ranges from 120-330 nm and 15%-20%,respectively.TEM and SEM observations indicated a raspberry-like morphology of the obtained nanocomposite particles.

  18. Synthesis and Characterization of Waterborne Fluoropolymers Prepared by the One-Step Semi-Continuous Emulsion Polymerization of Chlorotrifluoroethylene, Vinyl Acetate, Butyl Acrylate, Veova 10 and Acrylic Acid

    Directory of Open Access Journals (Sweden)

    Hongzhu Liu

    2017-01-01

    Full Text Available Waterborne fluoropolymer emulsions were synthesized using the one-step semi-continuous seed emulsion polymerization of chlorotrifluoroethylene (CTFE, vinyl acetate (VAc, n-butyl acrylate (BA, Veova 10, and acrylic acid (AA. The main physical parameters of the polymer emulsions were tested and analyzed. Characteristics of the polymer films such as thermal stability, glass transition temperature, film-forming properties, and IR spectrum were studied. Meanwhile, the weatherability of fluoride coatings formulated by the waterborne fluoropolymer and other coatings were evaluated by the quick ultraviolet (QUV accelerated weathering test, and the results showed that the fluoropolymer with more than 12% fluoride content possessed outstanding weather resistance. Moreover, scale-up and industrial-scale experiments of waterborne fluoropolymer emulsions were also performed and investigated.

  19. A B C分类管理方法在海事安全管理中的应用%ABC Classification in Waterborne Traffic Accidents Safety Management

    Institute of Scientific and Technical Information of China (English)

    熊振南

    2001-01-01

    将仓储管理ABC分类法引入海事的安全管理中,以便于安全管理部门针对不同水域的海事发生频率、危险程度,制定不同的安全管理对策,并能够充分利用有限的管理资源以提高海事安全管理水平.%If the ABC classification is applied to the management of the waterborne traffic safety,it is convenient for the safety management department to establish different management countermeasures according to the different frequency and criticality of waterborne traffic accidents in different shipping area,shipping company,etc,and to make full use the best of the limited resources in order to improve the management level of waterborne traffic safety.

  20. 高固含量水性聚氨酯的研究进展%Research Progress of Waterborne Polyurethane with High Solid Content

    Institute of Scientific and Technical Information of China (English)

    彭绍军; 金勇; 漆锐

    2013-01-01

    The technical difficulties in the synthesis of waterborne polyurethane with high solid content were introduced based on the solid content limitation theory of latex.The progress in the synthesis of high solid content of waterborne polyurethane was reviewed.The developing direction of waterborne polyurethane with high solid content was prospected.%通过对乳液固含量极限理论的介绍,阐述了高固含量水性聚氨酯合成的技术难点,综述了高固含量水性聚氨酯的合成研究进展,并对其发展方向进行了展望.

  1. The Research Progress of Modification for the Functional Waterborne Polyurethane%功能水性聚氨酯的改性研究进展

    Institute of Scientific and Technical Information of China (English)

    孙道兴; 莫莉

    2012-01-01

    综述了功能水性聚氨酯的几种最常用的改性方法。介绍了丙烯酸酯改性、环氧树脂改性、有机硅改性、有机氟改性和纳米材料改性等不同改性技术的特点和制备方法,并对功能水性聚氨酯的进一步发展作了展望。%The research progress of modification technology for functional waterborne polyurethane was reviewed.The characteristics and preparation methods of waterborne polyurethane modified by acrylate, epoxy resin, organic silicon, organic fluorine, and nano materials were introduced. In the end of this paper, the prospective development of functional waterborne polyurethane was put forward.

  2. Research and Recent Progress of Waterborne Polyurethane for Gloves%手套用水性聚氨酯的研究现状与最新进展

    Institute of Scientific and Technical Information of China (English)

    张晓辉; 杨建军; 吴庆云; 张建安; 吴明元

    2014-01-01

    According to the different product methods, function and application, a general gloves classification was introduced. The applications of waterborne polyurethane coatings used in rubber gloves,fiber gloves and PVC plastic gloves were introduced. The research and recent progress of gloves using waterborne polyurethane and natu-ral latex modified by waterborne polyurethane as the substrate were described.%按制作方法、功能、用途的不同对手套的分类进行了简单介绍。并介绍了水性聚氨酯涂层在橡胶手套、纤维手套及PVC塑料手套中应用,以及水性聚氨酯为基材的手套、水性聚氨酯改性天然乳胶为基材的手套国内外的研究现状和最新进展。

  3. Research progress on catalysts of waterborne polyurethane coatings%水性聚氨酯涂料催化剂研究进展

    Institute of Scientific and Technical Information of China (English)

    王庭慰; 陈存友; 狄超; 胡万成

    2011-01-01

    With the growing environmental awareness, more and more importance has been attached to waterborne polyurethane coatings. Catalyst is an important part of waterborne polyurethane coating. In this paper, a review of research status of catalysts used for waterborne polyurethane coatings was given, including amine catalysts, metal organic compound catalysts and composite catalysts, etc.%随着环保意识的逐渐加强,水性聚氨酯涂料越来越受到重视.催化剂是水性聚氨酯涂料的重要组成部分.本文综述了水性聚氨酯催化剂(包括胺类催化剂、金属有机化合物类催化剂和复合催化剂等)的研究状况.

  4. Research Progress of Waterborne Polyurethane with High Solid Content%高固含量水性聚氨酯的研究进展(续)

    Institute of Scientific and Technical Information of China (English)

    彭绍军; 金勇; 漆锐

    2013-01-01

    The technical difficulties in the synthesis of waterborne polyurethane with high solid content were introduced based on the solid content limitation theory of latex.The progress in the synthesis of high solid content of waterborne polyurethane was reviewed.The developing direction of waterborne polyurethane with high solid content was prospected.%通过对乳液固含量极限理论的介绍,阐述了高固含量水性聚氨酯合成的技术难点,综述了高固含量水性聚氨酯的合成研究进展,并对其发展方向进行了展望.

  5. Synthesis and Characterization of Waterborne Fluoropolymers Prepared by the One-Step Semi-Continuous Emulsion Polymerization of Chlorotrifluoroethylene, Vinyl Acetate, Butyl Acrylate, Veova 10 and Acrylic Acid.

    Science.gov (United States)

    Liu, Hongzhu; Bian, Jiming; Wang, Zhonggang; Hou, Chuan-Jin

    2017-01-22

    Waterborne fluoropolymer emulsions were synthesized using the one-step semi-continuous seed emulsion polymerization of chlorotrifluoroethylene (CTFE), vinyl acetate (VAc), n-butyl acrylate (BA), Veova 10, and acrylic acid (AA). The main physical parameters of the polymer emulsions were tested and analyzed. Characteristics of the polymer films such as thermal stability, glass transition temperature, film-forming properties, and IR spectrum were studied. Meanwhile, the weatherability of fluoride coatings formulated by the waterborne fluoropolymer and other coatings were evaluated by the quick ultraviolet (QUV) accelerated weathering test, and the results showed that the fluoropolymer with more than 12% fluoride content possessed outstanding weather resistance. Moreover, scale-up and industrial-scale experiments of waterborne fluoropolymer emulsions were also performed and investigated.

  6. Waterborne typhoid fever in Dade County, Florida. Clinical and therapeutic evaluation of 105 bacteremic patients.

    Science.gov (United States)

    Hoffman, T A; Ruiz, C J; Counts, G W; Sachs, J M; Nitzkin, J L

    1975-10-01

    An extensive outbreak of waterborne typhoid fever occurred in 1973 at a migrant labor camp in Dade County, Florida. Blood cultures from 105 of the 188 patients with proved or presumptive cases of typhoid fever grew Salmonella typhi. The clinical and laboratory findings in these patients were reviewed. Fever, usually with temperatures above 38.8 degrees C and of the sustained type, was a primary manifestation of disease, although a majority of the patients also complained of headache and gastroenteric symptoms. Hepatic or splenic enlargement was present in 52 per cent and 42 per cent, respectively, whereas rose spots were detected in only 13 per cent. The total leukocyte count was normal in 74 per cent, but serum levels of liver and muscle enzymes were frequently elevated. Gastrointestinal, pulmonary and neurologic complications were infrequent; circulatory failure was not observed. Defervescence in response to antibiotic therapy was variable; however, the median response among 68 patients who received chloramphenicol was two days less than that in 34 patients treated with ampicillin. There was one possible treatment failure with ampicillin. The relapse rate of 10 per cent in chloramphenicol-treated patients was not significantly greater than the 3 per cent rate among those treated with ampicillin. Serologic studies for typhoid fever were of limited diagnostic value since the titer of agglutinins was 1:160 or higher in 49 per cent of the serums obtained before treatment, and a fourfold rise in titer occurred in only 24 per cent of 57 patients studied. The serologic response to chloramphenicol treatment did not differ from that to ampicillin.

  7. Hepatitis E virus: A leading cause of waterborne viral hepatitis in Northwest Districts of Punjab, India

    Science.gov (United States)

    Kaur, Maninder; Sidhu, Shailpreet K.; Singh, Kanwardeep; Devi, Pushpa; Kaur, Manpreet; Singh, Nachhatar Jit

    2017-01-01

    BACKGROUND: Acute viral hepatitis (AVH) caused by enterically transmitted hepatitis A virus (HAV) and hepatitis E virus (HEV) poses a major health problem in developing countries such as India. Despite improving sanitation, heath awareness, and socioeconomic conditions, these infections continue to occur both in sporadic as well as in epidemic forms in different parts of India. AIMS: The aim of this study is to determine the total as well as age-specific prevalence rates of HAV and HEV in the outbreaks of waterborne hepatitis in districts surrounding Amritsar region of Punjab. MATERIALS AND METHODS: The study was conducted in the Virology Research and Diagnostic Laboratory, Government Medical College, Amritsar, during the study period of January 2015–March 2016. Samples from suspected outbreaks of AVH occurring in various districts around Amritsar were included as a part of the study. A total of 95 sera were tested for IgM antibody to HEV and HAV using IgM capture ELISA kit. RESULTS: Out of the total 95 samples received, 73 samples (76.84%) were positive for HAV/HEV. Out of the total positive cases, 65 (68.42%) had HEV infection, 2 (2.1%) had HAV, and 6 cases (6.31%) were coinfected with both HAV and HEV. The 21–30 years age group (25 cases) was identified as the most susceptible group for HEV infection. The coinfected subjects presented a wider range of age distribution (1–10 years: 1; 11–20 years: 3; 21–30 years: 1; 31–40 years: 1). Seasonal distribution of data revealed bimodal peaks for HEV infection. CONCLUSION: There should be some surveillance system to regularly monitor the portability of drinking water from time to time to avoid such preventable outbreaks in future.

  8. Potential molecular tools for assessing the public health risk associated with waterborne Cryptosporidium oocysts.

    Science.gov (United States)

    Kothavade, Rajendra J

    2012-08-01

    The use of multiple barrier stages at water and wastewater treatment facilities allows for the effective removal of the vast majority of coliforms and other enteric and non-enteric microbes. Subsequent disinfection steps (chlorine, ozone and UV irradiation) are utilized to inactivate microbes that escape the preceding treatment stages. Most viruses, bacteria and protozoa, such as Giardia, are effectively inactivated by chlorination; however, Cryptosporidium is relatively more resistant to environmental conditions and to chlorination. Therefore, UV disinfection has been introduced at many water and wastewater treatment plants to increase log inactivation. Any accidental treatment failure may pose a significant risk to public health. Waterborne transmission of coccidian parasites such as Cryptosporidium and Giardia continues to be a major public health concern. No effective therapies currently exist to treat cryptosporidiosis and the global increase in immunocompromised populations has emphasized the need for water utilities and public health laboratories to have immediate and reliable access to highly sensitive test methods that can determine the host specificity, viability and infectivity of protozoa in the water supply. The most common method used for monitoring Cryptosporidium oocysts and Giardia cysts at intermediate treatment stages and in finished drinking water is the US EPA Method 1623. Although Cryptosporidium species are morphologically indistinguishable, they differ greatly in their host specificity and infectivity. Method 1623 provides quantitative information about Cryptosporidium and Giardia contamination but cannot distinguish between species for intervention purposes in outbreak situations, nor is this method reliable for determining whether the oocyst on the slide is infective for humans. Molecular methods have proven valuable in diagnosing infectious diseases, especially those for which the causative agent is difficult to grow in culture, and

  9. The biocompatibility and antibacterial properties of waterborne polyurethane-silver nanocomposites.

    Science.gov (United States)

    Hsu, Shan-hui; Tseng, Hsiang-Jung; Lin, Yu-Chun

    2010-09-01

    Nanocomposites from a polyester-type waterborne polyurethane (PU) containing various low concentrations (15-75 ppm) of silver nanoparticles (nano Ag, size approximately 5 nm) were prepared. The PU-Ag nanocomposites exhibited good nanoparticle dispersion up to 30 ppm of nano Ag, confirmed by the transmission electron microscopy. Distinct surface morphology at different concentrations of nano Ag was shown by the atomic force microscopy. The oxidative degradation of PU-Ag was inhibited in all concentrations of nano Ag tested, especially at 30 ppm ("PU-Ag 30 ppm"). This may be related to the free radical scavenging ability observed for the nanocomposites. PU-Ag 30 ppm showed enhanced fibroblast attachment and endothelial cell response, as well as reduced monocyte and platelet activation, relative to PU alone or nanocomposites at the other silver contents. The rat subcutaneous implantation confirmed the better biocompatibility of the nanocomposites. The adhesion of Bacillus subtilis, Escherichia (E.) coli or Ag(+)-resistant E. coli on PU-Ag nanocomposites was significantly lower at all concentrations of nano Ag tested. Besides, the nanocomposites demonstrated microbiostatic effect while pure PU did not. The commercial catheters coated with PU-Ag 30 ppm were inserted into rat jugular veins for evaluation. The results showed milder inflammation for PU-Ag after 3 months compared to the non-coated catheters or pure PU-coated catheters. The enhanced performance of PU-Ag over that of pure PU was a result of extensively modified surface morphology in the presence of a very small amount of nano Ag. The dispersion of nano Ag was highly associated with the overall performance. Copyright 2010 Elsevier Ltd. All rights reserved.

  10. Occurrence and infection risk of waterborne pathogens in Wanzhou watershed of the Three Gorges Reservoir, China

    Institute of Scientific and Technical Information of China (English)

    Guosheng Xiao; Zhaodan Wang; Ji'an Chen; Zhiqun Qiu; Yanjie Li; Junsheng Qi; Wenyi Liu

    2013-01-01

    The Three Gorges Reservoir (TGR),formed by China's Yangtze Three Gorges Project,is the largest lake in the world,but there is too little information available about fecal contamination and waterborne pathogen impacts on this aquatic ecosystem.During two successive 1-year study periods (July 2009 to July 2011),the water quality in Wanzhou watershed of the TGR was tested with regard to the presence of fecal indicators and pathogens.According to Chinese and World Health Organization water quality standards,water quality in the mainstream was good but poor in backwater areas.Salmonella,Enterohemorrhagic Escherichia coli (EHEC),Giardia and Cryptosporidium were detected in the watershed.Prevalence and concentrations of the pathogens in the mainstream were lower than those in backwater areas.The estimated risk of infection with Salmonella,EHEC,Cryptosporidium,and Giardia per exposure event ranged from 2.9 × 10-7 to 1.68 × 10-5,7.04 × 10-10 to 2.36 × 10-7,5.39 × 10-6 to 1.25 × 10-4 and 0 to 1.2 × 10-3,respectively,for occupational divers and recreational swimmers exposed to the waters.The estimated risk of infection at exposure to the 95% upper confidence limit concentrations of Salmonella,Cryptosporidium and Giardia may be up to 2.62 × 10-5,2.55 × 10-4 and 2.86 × 10-3,respectively.This study provides useful information for the residents,health care workers and managers to improve the safety of surface water and reduce the risk of fecal contamination in the TGR.

  11. Occurrence of waterborne pathogens and Escherichia coli at offshore drinking water intakes in lake Ontario.

    Science.gov (United States)

    Edge, T A; Khan, I U H; Bouchard, R; Guo, J; Hill, S; Locas, A; Moore, L; Neumann, N; Nowak, E; Payment, P; Yang, R; Yerubandi, R; Watson, S

    2013-10-01

    The occurrence of waterborne pathogens was investigated at three drinking water intakes located about 2 km offshore in Lake Ontario. Water sampling was conducted over 3 years for Campylobacter spp., Cryptosporidium spp., Giardia spp., cultivable enteric viruses, and water quality parameters. All pathogens were detected in the offshore source water for each water treatment plant (WTP1 to WTP3), although at relatively low frequencies and concentrations. Giardia was the most common pathogen, occurring in 36% of water samples from the influent of WTP1 (n = 46), and with a maximum concentration of 0.70 cysts/liter in this influent. Cryptosporidium occurred as frequently as 15% in the WTP2 influent (n = 35), with a maximum concentration of 0.40 oocysts/liter in the WTP1 influent. The human Bacteroidales HF183 DNA marker was most common in the WTP1 influent (19%), and this was the only WTP where the Cryptosporidium hominis genotype was detected. No water quality parameter was predictive of pathogen occurrence across all three WTP influents. Escherichia coli was often below detection when pathogens were detected, and spikes in E. coli concentrations often did not coincide with pathogen occurrence. After summer rain events, river plumes had E. coli concentrations as high as 222 CFU/100 ml in surface waters 2 km offshore, without impacting drinking water intakes below the thermocline on the lake bottom. At times, prechlorination to control mussels at offshore intake cribs compromised the use of E. coli for "raw" water quality assessment, particularly for chlorine-resistant Cryptosporidium. E. coli measured by standard methods did not reliably predict pathogen occurrence at drinking water intakes in offshore ecosystems.

  12. Waterborne iron acquisition by a freshwater teleost fish, zebrafish Danio rerio.

    Science.gov (United States)

    Bury, Nicolas R; Grosell, Martin

    2003-10-01

    Waterborne iron accumulation by the gills of the zebrafish Danio rerio was assessed in ion-poor water. Branchial iron uptake, which comprises both the iron that has entered the gill cells and iron that is strongly bound to the epithelia, has high- and low-affinity components. At low nominal [Fe] (reducing agent dithiothreitol (DTT), branchial iron accumulation was significantly enhanced at [Fe]>15 nmol l(-1). The proton pump inhibitor bafilomycin A significantly reduced iron uptake in the presence of DTT. On the basis of these observations we conclude that branchial iron uptake at low [Fe] shows characteristics similar to those of other iron-transporting epithelia, coupling an apical membrane ferric reductase to a Fe(2+)/H(+) symporter. Zebrafish branchial iron transport at 18.6 nmol l(-1) was inhibited by 200 nmol l(-1) Cd(2+). But, unlike other Fe(2+)/H(+) symporters, iron uptake was not affected by other divalent metals (Co(2+), Ni(2+), Pb(2+), Cu(2+), Zn(2+) and Mn(2+)). Zebrafish loaded with (59)Fe from the water showed a loss of 7.9 pmol Fe g(-1) body mass over the first day and a further loss of 5.7 pmol Fe g(-1) body mass over the following 28 days. The depuration kinetics followed a two-component exponential model; for the short-lived component, t(1/2)=0.31 days, and for the long-lived component, t(1/2)=13.2 days. The daily iron loss by zebrafish can be compensated by iron uptake at exceedingly low water iron concentrations (uptake rate at 1.625 nmol l(-1) Fe=0.425 pmol g(-1) h(-1)), demonstrating that uptake of iron from the water is potentially an important source of this nutritive metal in freshwater teleost fish.

  13. Nonreversible immobilization of water-borne plutonium onto self-assembled adlayers of silanized humic materials.

    Science.gov (United States)

    Shcherbina, Natalia S; Kalmykov, Stepan S; Karpiouk, Leonid A; Ponomarenko, Sergey A; Hatfield, Kirk; Haire, Richard; Perminova, Irina V

    2014-02-18

    The objective was to study plutonium partitioning between immobile and mobile humic materials at the water-solid interfaces. Immobilization of the humic materials on solid supports was performed in situ using self-adhesive silanized humic derivatives. The presence of the humic adlayers on solid supports was shown to significantly enhance Pu sorption and its retention under both steady state and dynamic conditions. While plutonium may exist in multiple oxidations states plus colloidal forms, the major thrust in this work was to study the behavior of most mobile--the PuO2(+) form in dilute solutions. The values of the plutonium partition coefficients (Kd) between water and humics-coated silica gels after 10 days exposure reached 1.6 × 10(4) L · kg(-1) at pH 7.5 under anaerobic conditions with a total plutonium concentration of 1.2 × 10(-8) M exceeding those for the uncoated SiO2 (6.3 × 10(2) L · kg(-1)). Column tests showed substantial sequestration of water-borne plutonium (up to 73%) on the humics-coated silica gels. Remobilization experiments conducted under batch conditions at different pH values (3.5, 4.5, 7.5) showed that no more than 3% of the sequestered Pu was remobilized from the humics-coated silica gels by treatment with dissolved humic materials at environmentally relevant pH of 7.5. Consequently, silanized humic materialas can be seen as both molecular probes and as potent candidate materials for scavenging mobile Pu from an aqueous phase.

  14. Enhanced bioaccumulation of dietary contaminants in catfish with exposure to the waterborne surfactant linear alkylbenzene sulfonate.

    Science.gov (United States)

    Tan, Xiaobing; Yim, Sun-Young; Uppu, Prasanna; Kleinow, Kevin M

    2010-08-15

    Fish bioaccumulate a variety of contaminants and act as an exposure portal to the human consumer. Surfactants, known pharmaceutically to alter membrane permeability, change drug bioavailability and attenuate transporter function are also found in contaminant mixtures in the aquatic environment. The overall objective of this study was to determine if the surfactant C-12 linear alkylbenzene sulfonate (LAS) at environmentally relevant concentrations, alters the disposition and enhances bioaccumulation of co-exposed dietary xenobiotics in the catfish. Included for study were the carcinogen benzo(a)pyrene (BaP), pharmaceutical, ivermectin (IVM), and P-glycoprotein (P-gp) substrate rhodamine 123 (Rho-123), each exhibiting different dispositional footprints. Rho-123 transport into bile and membrane fluidity was examined in isolated perfused livers from control and LAS exposed catfish. Mass balance residue assessments were performed on catfish following in vivo exposure for 12 days to LAS in water at 0, 100 or 300 microg/L with 6 days of (3)H-IVM or (3)H-BaP gavage treatments. LAS at 1, 5 and 20 microM in the perfused liver, significantly decreased the transport of Rho-123 (1 microM) into bile by 18.6, 38.1 and 66.7%, respectively. Fluorescence anisotropy measurements demonstrated a 29.7% increase in fluidity at the (1 microM, 348 microg/L) LAS concentration. In vivo mass balance studies indicated that waterborne LAS (100 and 300 microg/L) increased the dietary dose remaining in fish by 39% and 78% for (3)H-IVM and 50 and 157% for (3)H-BaP. LAS at environmentally relevant concentrations altered the bioavailability and disposition of dietary xenobiotics in the catfish. Co-exposure with LAS increases xenobiotic bioaccumulation, potential toxicity of mixture components to the fish and the potential for residue transfer from fish to the consumer.

  15. Waterborne toxicity and diet-related effects of fungicides in the key leaf shredder Gammarus fossarum (Crustacea: Amphipoda).

    Science.gov (United States)

    Zubrod, J P; Englert, D; Wolfram, J; Wallace, D; Schnetzer, N; Baudy, P; Konschak, M; Schulz, R; Bundschuh, M

    2015-12-01

    Animals involved in leaf litter breakdown (i.e., shredders) play a central role in detritus-based stream food webs, while their fitness and functioning can be impaired by anthropogenic stressors. Particularly fungicides can affect shredders via both waterborne exposure and their diet, namely due to co-ingestion of adsorbed fungicides and shifts in the leaf-associated fungal community, on which shredders' nutrition heavily relies. To understand the relevance of these effect pathways, we used a full 2×2-factorial test design: the leaf material serving as food was microbially colonized for 12 days either in a fungicide-free control or exposed to a mixture of five current-use fungicides (sum concentration of 62.5μg/L). Similarly, the amphipod shredder Gammarus fossarum was subjected to the same treatments but for 24 days. Waterborne exposure reduced leaf consumption by ∼20%, which did not fully explain the reduction in feces production (∼30%), indicating an enhanced utilization of food to compensate for detoxification mechanisms. This may also explain the reduced feces production (∼10%) of gammarids feeding on fungicide-exposed leaves. The reduction may, however, also be caused by a decreased nutritious quality of the leaves indicated by a reduced species richness (∼40%) of leaf-associated fungi. However, compensation for these effects by Gammarus was seemingly incomplete, since both waterborne exposure and the consumption of the fungicide-affected diet drastically reduced gammarid growth (∼110% and ∼40%, respectively). Our results thus indicate that fungicide mixtures have the potential for detrimental implications in aquatic ecosystem functioning by affecting shredders via both effect pathways.

  16. Exposure to environmental levels of waterborne cadmium impacts corticosteroidogenic and metabolic capacities, and compromises secondary stressor performance in rainbow trout

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu, Navdeep [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); McGeer, James C. [Department of Biology, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); Vijayan, Mathilakath M., E-mail: matt.vijayan@ucalgary.ca [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2014-01-15

    Highlights: •Low level chronic waterborne cadmium exposure did not evoke a plasma cortisol response in rainbow trout. •Chronic cadmium exposure increases liver and gill metabolic capacities. •Chronic cadmium exposure disrupts head kidney steroidogenic capacity. •Chronic cadmium exposure disrupts glucocorticoid and mineralocorticoid receptor protein expressions in target tissues. •Chronic cadmium exposure compromises physiological performances to a secondary stressor in trout. -- Abstract: The physiological responses to waterborne cadmium exposure have been well documented; however, few studies have examined animal performances at low exposure concentrations of this metal. We tested the hypothesis that longer-term exposure to low levels of cadmium will compromise the steroidogenic and metabolic capacities, and reduce the cortisol response to a secondary stressor in fish. To test this, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to 0 (control), 0.75 or 2.0 μg/L waterborne cadmium in a flow-through system and were sampled at 1, 7 and 28 d of exposure. There were only very slight disturbances in basal plasma cortisol, lactate or glucose levels in response to cadmium exposure over the 28 d period. Chronic cadmium exposure significantly affected key genes involved in corticosteroidogenesis, including melanocortin 2 receptor, steroidogenic acute regulatory protein and cytochrome P450 side chain cleavage enzyme. At 28 d, the high cadmium exposure group showed a significant drop in the glucocorticoid receptor and mineralocorticoid receptor protein expressions in the liver and brain, respectively. There were also perturbations in the metabolic capacities in the liver and gill of cadmium-exposed trout. Subjecting these fish to a secondary handling disturbance led to a significant attenuation of the stressor-induced plasma cortisol, glucose and lactate levels in the cadmium groups. Collectively, although trout appears to adjust to subchronic exposure

  17. Removal of the microorganisms from water. Part 1: Introduction, water-borne disease and the microorganisms involved.

    CSIR Research Space (South Africa)

    Duuren, FR

    1967-01-01

    Full Text Available in the spread (this) disease. Forward strides taken since, in sanitation and water ply practice, have all but eliminated the incidence of ~h major water-borne diseases as cholera and typhoid er in the western world. The improvements which ye been effected... colonies, demonstrated in his investigation of the Calcutta water supplies, the presence of Vibrio comma which caused the cholera epidemic 2 It is apparent from modern reporting that the con siderations applied in deciding on whether or not a disease...

  18. 脂肪族水性聚氨酯涂料的研制%Development of Waterborne Aliphatic Polyurethane Coatings

    Institute of Scientific and Technical Information of China (English)

    许戈文; 熊潜生; 等

    2001-01-01

    A waterborne aliphatic polyurethane coatings was prepared by epoxy resin modified polyurethane and IPDI instead of TDI. The in fluences ofreaction temperature, catalyst, NCO content and chain extender etc. on the paint property were discussed.%采用环氧树脂改性聚氨酯,异佛尔酮二异氰酸酯代替甲苯二异氰酸酯合成出耐候性好的水性聚氨酯树脂。讨论了反应温度、催化剂、NCO含量及扩链剂等对涂料性能的影响。

  19. Synthesis and characterization of mixing soft-segmented waterborne polyurethane polymer electrolyte with room temperature ionic liquid

    Institute of Scientific and Technical Information of China (English)

    Yue Jiao Li; Feng Wu; Ren Jie Chen

    2009-01-01

    Composite polymer electrolytes based on mixing soft-segment waterborne polyurethane (WPU) and 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (BMImTFSI) have been prepared and characterized.The addition of BMImTFSI results in an increase of the ionic conductivity.At high BMImTFSI concentration (BMImTFSI/WPU = 3 in weight ratio),the ionic conductivity reaches 4.27 × 10-3 S/cm at 30 ℃.These composite polymer electrolytes exhibit good thermal and electrochemical stability,which are high enough to be applied in lithium batteries.

  20. 紫外光固化水性聚氨酯技术%Technique of ultraviolet curing waterborne polyurethane

    Institute of Scientific and Technical Information of China (English)

    叶青萱

    2012-01-01

    The ultraviolet curable waterborne polyurethane (UV-WPU) belongs in high-efficiency, energe-saving.environment friendly new curing systems.lt is one of the most active branches in current PU chemistry.Characteristics,development course.compositions and preparations of UV-WPU were described briefly.%紫外光固化水性聚氨酯( UV-WPU)属高效、节能、环保的高新固化体系,是目前PU化学中最活跃分支之一.本文简述Uv-WPU特性、发展过程、组成及其制备方法.

  1. Ultrafine particles

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Weschler, Charles J.; Wierzbicka, Aneta;

    2013-01-01

    Particle number (PN) concentrations (10-300 nm in size) were continuously measured over a period of ∼45 h in 56 residences of nonsmokers in Copenhagen, Denmark. The highest concentrations were measured when occupants were present and awake (geometric mean, GM: 22.3 × 103 cm-3), the lowest when...... the homes were vacant (GM: 6.1 × 103 cm-3) or the occupants were asleep (GM: 5.1 × 103 cm-3). Diary entries regarding occupancy and particle related activities were used to identify source events and apportion the daily integrated exposure among sources. Source events clearly resulted in increased PN...... concentrations and decreased average particle diameter. For a given event, elevated particle concentrations persisted for several hours after the emission of fresh particles ceased. The residential daily integrated PN exposure in the 56 homes ranged between 37 × 103 and 6.0 × 106 particles per cm3·h/day (GM: 3...

  2. Particle therapy

    Energy Technology Data Exchange (ETDEWEB)

    Raju, M.R.

    1993-09-01

    Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics.

  3. Research Advance in Sulfonated Waterborne Polyurethane%磺酸盐型水性聚氨酯的研究进展

    Institute of Scientific and Technical Information of China (English)

    王贺; 张普玉

    2015-01-01

    In this paper, the author described main characteristics of sulfonated waterborne polyurethane (WPU), summarized the research progress in the synthesis and modification of sulfonated waterborne polyurethane and prospected the future developmental trend of SWPU.%介绍了磺酸盐型水性聚氨酯(SWPU)的主要特点,综述了近年来其合成及改性的研究进展,并对SWPU未来的发展方向进行了展望。

  4. 高性能水性聚氨酯消光光油的制备%The Preparation of High-performance Waterborne Polyurethane Matting Oil

    Institute of Scientific and Technical Information of China (English)

    孙大庆; 周炳才

    2015-01-01

    本文提出了一种高性能水性聚氨酯消光光油的制备方法,讨论了不同型号消光剂和水性聚氨酯光油及助剂对产品稳定性和使用性能的影响。%This paper presented a method of preparing a high-performance waterborne polyurethane matting oil.The effects of different types of matting agents and waterborne polyurethane varnish and additives on the stability and use performance of the product were discussed.

  5. Particle Physics

    CERN Document Server

    Martin, B R

    2008-01-01

    An essential introduction to particle physics, with coverage ranging from the basics through to the very latest developments, in an accessible and carefully structured text. Particle Physics: Third Edition is a revision of a highly regarded introduction to particle physics. In its two previous editions this book has proved to be an accessible and balanced introduction to modern particle physics, suitable for those students needed a more comprehensive introduction to the subject than provided by the 'compendium' style physics books. In the Third Edition the standard mod

  6. Dietary and waterborne exposure of rainbow trout (Oncorhynchus mykiss) to copper, cadmium, lead and zinc using a live diet

    Energy Technology Data Exchange (ETDEWEB)

    Mount, D.R.; Barth, A.K.; Garrison, T.D.; Barten, K.A.; Hockett, J.R. (ENSR Consulting and Engineering, Fort Collins, CO (United States))

    1994-12-01

    In two 60-d exposures, rainbow trout fry were fed brine shrimp (Artemia sp.) enriched with Cu, Cd, Pb, and Zn both individually and as a mixture combined with As. Dietary concentrations fed to trout were selected based on metal concentrations measured in invertebrates collected from the Clark Fork River (CFR), Montana. In addition to dietary exposure, treatments also included simultaneous exposure to a mixture of waterborne metals at sublethal concentrations. Fish in all treatments showed increased tissue metal concentrations from water and/or dietary exposure. Despite these accumulations, trout showed no effects on survival or growth from dietary concentrations as high as 55 [mu]g Cd/g dry weight, 170 [mu]g Pb/g dry weight, or 1,500 [mu]g Zn/g dry weight. Dietary Cu concentrations up to 350 [mu]g Cu/g dry weight did not reduce survival or growth. Fish fed Cu concentrations higher than those typical of CFR invertebrates showed about 30% mortality with no effect on growth; waterborne Cu released from Artemia may have contributed to this mortality. Trout exposed to diets with a mixture of Cu, Cd, Pb, Zn, and As close to that measured in CFR invertebrates showed lower weight than did control fish after 35 d, but this difference was no longer present after 60 d.

  7. Compound-specific carbon and hydrogen isotope analysis of sub-parts per billion level waterborne petroleum hydrocarbons

    Science.gov (United States)

    Wang, Y.; Huang, Y.; Huckins, J.N.; Petty, J.D.

    2004-01-01

    Compound-specific carbon and hydrogen isotope analysis (CSCIA and CSHIA) has been increasingly used to study the source, transport, and bioremediation of organic contaminants such as petroleum hydrocarbons. In natural aquatic systems, dissolved contaminants represent the bioavailable fraction that generally is of the greatest toxicological significance. However, determining the isotopic ratios of waterborne hydrophobic contaminants in natural waters is very challenging because of their extremely low concentrations (often at sub-parts ber billion, or even lower). To acquire sufficient quantities of polycyclic aromatic hydrocarbons with 10 ng/L concentration for CSHIA, more than 1000 L of water must be extracted. Conventional liquid/liquid or solid-phase extraction is not suitable for such large volume extractions. We have developed a new approach that is capable of efficiently sampling sub-parts per billion level waterborne petroleum hydrocarbons for CSIA. We use semipermeable membrane devices (SPMDs) to accumulate hydrophobic contaminants from polluted waters and then recover the compounds in the laboratory for CSIA. In this study, we demonstrate, under a variety of experimental conditions (different concentrations, temperatures, and turbulence levels), that SPMD-associated processes do not induce C and H isotopic fractionations. The applicability of SPMD-CSIA technology to natural systems is further demonstrated by determining the ??13C and ??D values of petroleum hydrocarbons present in the Pawtuxet River, RI. Our results show that the combined SPMD-CSIA is an effective tool to investigate the source and fate of hydrophobic contaminants in the aquatic environments.

  8. The Influence of Drinking Water Access on the Occurrence of Water-borne Diseases (Diarrhea and Typhoid

    Directory of Open Access Journals (Sweden)

    Khadijah Azhar

    2015-01-01

    Full Text Available Background: Poor and inadequate drinking water supply are the cause of the high occurrence of water-borne diseases,such as diarrhea and typhoid. These diseases often caused an outbreak among the citizens. This article was a furtheranalysis of data obtained from Basic Health Research (Riskesdas in 2007 with the aim to figure out the influence of drinkingwater access against the occurrence of diarrhea and typhoid. Methods: the used samples were taken from all samples ofthe 2007 Riskesdas, which had complete data about drinking water supply. The dependent variables were diarrhea andtyphoid, and the independent variables were total water usage, physical quality of the water, the water access, type offacilities, type of sanitation facilities, hygiene behavior (e. g. hand washing with soap before having and preparing meals,hand washing with soap after defecation, the use of latrine, and characteristic of respondents (educational background,occupation, age, and gender. Analysis was performed by using bivariate and multivariate logistic regression. Results:showed that diarrhea and typhoid were influenced by the difficulty of the access to get water from sources, difficulty levelfor obtaining the water, non physical-standards water, low educational background, behavior of hand washing and latrineusage. Conclusion: was water-borne diseases occured if the access of water was limited, inadequate water’s physicalquality and unhigienic behavior.

  9. Stable Photocatalytic Paints Prepared from Hybrid Core-Shell Fluorinated/Acrylic/TiO2 Waterborne Dispersions

    Directory of Open Access Journals (Sweden)

    Audrey Bonnefond

    2016-10-01

    Full Text Available The contamination of air and water is one of the major concerns towards the development of a sustainable world in the 21st century. In this context many efforts are devoted to the design of photocatalytic paints able to degrade chemical and biological impurities present in air and water. In this work, the photocatalytic activity of hybrid films formed from the blends of pure acrylic or core/shell fluorinated/acrylic waterborne dispersions and photocatalytic titanium dioxide (TiO2 nanoparticle dispersions was first assessed. The films show photocatalytic activity (inactivation of the Escherichia coli bacteria under UV irradiation at the substrate-film interface, but very reduced activity in the air-film interface due to the substantially lower amount of the TiO2 nanoparticles in the vicinity of this interface. In a second step, the fluorinated/(methacrylic core-shell hybrid dispersions were used as binders in the formulation of waterborne photocatalytic paints and the stability of the paints, in terms of gloss retain and color change, was assessed during 5000 hours of accelerated weathering tests (QUV-B. Although a decrease in gloss retention and increased color change occurs during the first 1000 hours of exposure, no further change of these properties takes place, which is an excellent indication of stable photocatalytic paints.

  10. Knowledge, Attitude, and Practice regarding Food, and Waterborne Outbreak after Massive Diarrhea Outbreak in Yazd Province, Iran, Summer 2013.

    Science.gov (United States)

    Cheraghi, Zahra; Okhovat, Batul; Doosti Irani, Amin; Talaei, Mojgan; Ahmadnezhad, Elham; Gooya, Mohammad Mehdi; Soroush, Mahmood; Masoumi Asl, Hossein; Holakouie-Naieni, Kourosh

    2014-01-01

    Objective. This Study was conducted after a diarrhea outbreak that occurred in Yazd Province, Iran. The aim of the study was to compare knowledge, attitude, practice, and other risk factors of the affected communities regarding diarrhea outbreak (the cities of Zarch, Meybod, and Ardakan) to nonaffected communities (the cities of Yazd and Taft). Methods. A knowledge, attitude, and practice (KAP) survey study was conducted from August to September 2013 enrolling 505 subjects who were referred to health centers anonymously during the epidemic. The questionnaire included the following four parts: (a) general characteristics such as gender, education level, source of health information obtaining; (b) 12 questions on knowledge (Min = 0, Max = 36); (c) 10 questions on attitude (Min = 0, Max = 50); and (d) nine questions on practice (Min = 0, Max = 27). Results. The overall mean score of knowledge, attitude, and practice was 28.17 (SD = 4.58), 37.07 (SD = 4.39), and 21.31 (SD = 3.81), respectively. Practice on food- and waterborne outbreaks was significantly higher in females (P = 0.001) and in nonaffected communities (P = 0.031). Conclusions. Nonaffected communities had a considerably better practice score. With the increase in the score of knowledge about food- and waterborne outbreaks, the score of practice increased slightly.

  11. Bioaccumulation and toxicity of CuO nanoparticles by a freshwater invertebrate after waterborne and dietborne exposures

    Science.gov (United States)

    Croteau, Marie-Noele; Misra, Superb K.; Luoma, Samuel N.; Valsami-Jones, Eugenia

    2014-01-01

    The incidental ingestion of engineered nanoparticles (NPs) can be an important route of uptake for aquatic organisms. Yet, knowledge of dietary bioavailability and toxicity of NPs is scarce. Here we used isotopically modified copper oxide (65CuO) NPs to characterize the processes governing their bioaccumulation in a freshwater snail after waterborne and dietborne exposures. Lymnaea stagnalis efficiently accumulated 65Cu after aqueous and dietary exposures to 65CuO NPs. Cu assimilation efficiency and feeding rates averaged 83% and 0.61 g g–1 d–1 at low exposure concentrations (–1), and declined by nearly 50% above this concentration. We estimated that 80–90% of the bioaccumulated 65Cu concentration in L. stagnalis originated from the 65CuO NPs, suggesting that dissolution had a negligible influence on Cu uptake from the NPs under our experimental conditions. The physiological loss of 65Cu incorporated into tissues after exposures to 65CuO NPs was rapid over the first days of depuration and not detectable thereafter. As a result, large Cu body concentrations are expected in L. stagnalis after exposure to CuO NPs. To the degree that there is a link between bioaccumulation and toxicity, dietborne exposures to CuO NPs are likely to elicit adverse effects more readily than waterborne exposures.

  12. A novel silanized CoFe{sub 2}O{sub 4}/fluorinated waterborne polyurethane pressure sensitive adhesive

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Heqing, E-mail: fuhq@scut.edu.cn; Wang, Yin; Chen, Weifeng; Zhou, Wei; Xiao, Jing

    2015-10-01

    Highlights: • The hydrophobicity, thermal stability, dynamic mechanical properties, as well as adhesive properties of silanized. • CoFe{sub 2}O{sub 4}/fluorinated waterborne polyurethane (SC/FWPU) were improved with the incorporation of silanized CoFe{sub 2}O{sub 4} into FWPU. • The higher the spreading-penetration parameter is, the faster the contact angle reaches equilibrium, and the faster the SC/FWPU pressure sensitive adhesive penetrates and spreads. - Abstract: A novel silanized CoFe{sub 2}O{sub 4}/fluorinated waterborne polyurethane (SC/FWPU) pressure sensitive adhesive was synthesized and characterized by atomic force microscopy (AFM), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and contact angle tester. The adhesive properties were measured in a test machine. Experimental results showed that the hydrophobicity, thermal stability, dynamic mechanical properties, as well as adhesive properties of SC/FWPU were improved with the incorporation of SC into FWPU. The dynamic hydrophobicity can be well described by the wetting kinetic model. The spreading-penetration parameter increased with an increase in SC content. The higher the spreading-penetration parameter is, the faster the contact angle reaches equilibrium, and the faster the SC/FWPU pressure sensitive adhesive penetrates and spreads.

  13. Role and mechanism of the AMPK pathway in waterborne Zn exposure influencing the hepatic energy metabolism of Synechogobius hasta

    Science.gov (United States)

    Wu, Kun; Huang, Chao; Shi, Xi; Chen, Feng; Xu, Yi-Huan; Pan, Ya-Xiong; Luo, Zhi; Liu, Xu

    2016-12-01

    Previous studies have investigated the physiological responses in the liver of Synechogobius hasta exposed to waterborne zinc (Zn). However, at present, very little is known about the underlying molecular mechanisms of these responses. In this study, RNA sequencing (RNA-seq) was performed to analyse the differences in the hepatic transcriptomes between control and Zn-exposed S. hasta. A total of 36,339 unigenes and 1,615 bp of unigene N50 were detected. These genes were further annotated to the Nonredundant protein (NR), Nonredundant nucleotide (Nt), Swiss-Prot, Kyoto Encyclopedia of Genes and Genomes (KEGG), Clusters of Orthologous Groups (COG) and Gene Ontology (GO) databases. After 60 days of Zn exposure, 708 and 237 genes were significantly up- and down-regulated, respectively. Many differentially expressed genes (DEGs) involved in energy metabolic pathways were identified, and their expression profiles suggested increased catabolic processes and reduced biosynthetic processes. These changes indicated that waterborne Zn exposure increased the energy production and requirement, which was related to the activation of the AMPK signalling pathway. Furthermore, using the primary hepatocytes of S. hasta, we identified the role of the AMPK signalling pathway in Zn-influenced energy metabolism.

  14. The effects of acute waterborne exposure to sublethal concentrations of molybdenum on the stress response in rainbow trout, Oncorhynchus mykiss.

    Directory of Open Access Journals (Sweden)

    Chelsea D Ricketts

    Full Text Available To determine if molybdenum (Mo is a chemical stressor, fingerling and juvenile rainbow trout (Oncorhynchus mykiss were exposed to waterborne sodium molybdate (0, 2, 20, or 1,000 mg l-1 of Mo and components of the physiological (plasma cortisol, blood glucose, and hematocrit and cellular (heat shock protein [hsp] 72, hsp73, and hsp90 in the liver, gills, heart, and erythrocytes and metallothionein [MT] in the liver and gills stress responses were measured prior to initiation of exposure and at 8, 24, and 96 h. During the acute exposure, plasma cortisol, blood glucose, and hematocrit levels remained unchanged in all treatments. Heat shock protein 72 was not induced as a result of exposure and there were no detectable changes in total hsp70 (72 and 73, hsp90, and MT levels in any of the tissues relative to controls. Both fingerling and juvenile fish responded with similar lack of apparent sensitivity to Mo exposure. These experiments demonstrate that exposure to waterborne Mo of up to 1,000 mg l(-1 did not activate a physiological or cellular stress response in fish. Information from this study suggests that Mo water quality guidelines for the protection of aquatic life are highly protective of freshwater fish, namely rainbow trout.

  15. Structure Sensitivity Study of Waterborne Contaminant Hydrogenation Using Shape- and Size-Controlled Pd Nanoparticles

    KAUST Repository

    Shuai, Danmeng

    2013-03-01

    Catalytic reduction with Pd has emerged as a promising technology to remove a suite of contaminants from drinking water, such as oxyanions, disinfection byproducts, and halogenated pollutants, but low activity is a major challenge for application. To address this challenge, we synthesized a set of shape- and size-controlled Pd nanoparticles and evaluated the activity of three probe contaminants (i.e., nitrite, N-nitrosodimethylamine (NDMA), and diatrizoate) as a function of facet type (e.g., (100), (110), (111)), ratios of low- to high-coordination sites, and ratios of surface sites to total Pd (i.e., dispersion). Reduction results for an initial contaminant concentration of 100 μM show that initial turnover frequency (TOF0) for nitrite increases 4.7-fold with increasing percent of (100) surface Pd sites (from 0% to 95.3%), whereas the TOF0 for NDMA and for diatrizoate increases 4.5- and 3.6-fold, respectively, with an increasing percent of terrace surface Pd sites (from 79.8% to 95.3%). Results for an initial nitrite concentration of 2 mM show that TOF0 is the same for all shape- and size-controlled Pd nanoparticles. Trends for TOF0 were supported by results showing that all catalysts but one were stable in shape and size up to 12 days; for the exception, iodide liberation in diatrizoate reduction appeared to be responsible for a shape change of 4 nm octahedral Pd nanoparticles. Density functional theory (DFT) simulations for the free energy change of hydrogen (H2), nitrite, and nitric oxide (NO) adsorption and a two-site model based on the Langmuir-Hinshelwood mechanism suggest that competition of adsorbates for different Pd sites can explain the TOF0 results. Our study shows for the first time that catalytic reduction activity for waterborne contaminant removal varies with the Pd shape and size, and it suggests that Pd catalysts can be tailored for optimal performance to treat a variety of contaminants for drinking water. © 2013 American Chemical Society.

  16. Waterborne cadmium impacts immunocytotoxic and cytogenotoxic endpoints in green-lipped mussel, Perna canaliculus

    Energy Technology Data Exchange (ETDEWEB)

    Chandurvelan, Rathishri, E-mail: rch118@uclive.ac.nz [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); Marsden, Islay D., E-mail: islay.marsden@canterbury.ac.nz [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); Gaw, Sally, E-mail: sally.gaw@canterbury.ac.nz [Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); Glover, Chris N., E-mail: chris.glover@canterbury.ac.nz [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand)

    2013-10-15

    Highlights: •Cadmium (Cd) significantly altered the proportional composition of haemocytes. •Subchronic exposure increased nuclear aberrations in gill cells. •Branchial nuclear aberrations correlated significantly with gill Cd accumulation. •Cd induced DNA damage in haemocytes. -- Abstract: Mussels are sentinel species that can be used to monitor coastal metal pollution through the application of biomarkers. Among the several important metal toxicants in coastal settings, cadmium (Cd) is of particular concern, being a non-essential metal that is known to cause harmful impacts in aquatic organisms at low concentrations. The aim of the present study was to examine the immunocytotoxic and cytogenotoxic effects of Cd on the green-lipped mussel, Perna canaliculus, under laboratory conditions. The acute (96 h; 0, 2000 and 4000 μg Cd L{sup −1}) and subchronic (28 d; 0, 200 and 2000 μg Cd L{sup −1}) toxic effects of waterborne Cd were measured in haemocytes and gill cells using differential haemocyte cell count, the micronucleus test and the comet assay. During subchronic exposure to Cd the relative counts of eosinophils and hyalinocytes increased significantly in Cd-exposed mussels while the proportion of basophils decreased. All of these effects were time- and concentration-dependent. Conversely, the relative numbers of basophils and eosinophils increased significantly during acute Cd exposure. Nuclear aberrations such as the formation of micronuclei, nuclear buds, fragmented-apoptotic cells and binuclei were observed in gill cells of Cd-exposed mussels. All of these parameters increased significantly at 2000 μg Cd L{sup −1} during subchronic exposure to Cd, and all showed a strong and significant correlation to gill Cd accumulation. Comet assay results demonstrated a significant increase in DNA damage in the haemocytes of mussels exposed to subchronic Cd concentrations. The results indicate that Cd has the capacity to induce immune system and genotoxic

  17. A large waterborne outbreak of campylobacteriosis in Norway: The need to focus on distribution system safety

    Directory of Open Access Journals (Sweden)

    Lund Helge

    2008-09-01

    Full Text Available Abstract Background On 7 May 2007 the medical officer in Røros (population 5600 reported 15 patients with gastroenteritis. Three days later he estimated hundreds being ill. Untreated tap water from a groundwater source was suspected as the vehicle and chlorination was started 11 May. Campylobacter was isolated from patients' stool samples. We conducted an investigation to identify the source and describe the extent of the outbreak. Methods We undertook a retrospective cohort study among a random sample of customers of Røros and neighbouring Holtålen waterworks. Holtålen, which has a different water source, was used as a control city. We conducted telephone interviews to gather data on illness from all household members. One randomly selected household member was asked about detailed exposure history. The regional hospital laboratory tested patients' stools for enteropathogens. Campylobacter isolates were typed by AFLP for genetic similarity at the Norwegian Institute of Public Health. Local authorities conducted the environmental investigation. Results We identified 105 cases among 340 individuals from Røros and Holtålen (Attack Rate = 31%. Tap water consumption was the only exposure associated with illness. Among randomly selected household members from Røros, a dose-response relationship was observed in daily consumed glasses of tap water (χ2 for trend = 8.1, p = 0.004. Campylobacter with identical AFLP was isolated from 25 out of 26 submitted stool samples. No pathogens were detected in water samples. We identified several events that might have caused pressure fall and influx of contaminated water into the water distribution system. On two occasions, pressure fall was noticed and parts of the distribution system were outdated. Conclusion The investigation confirmed a waterborne outbreak of campylobacteriosis in Røros. Although no single event was identified as the cause of contamination, this outbreak illustrates the vulnerability

  18. Water Safety Plan on cruise ships: A promising tool to prevent waterborne diseases

    Energy Technology Data Exchange (ETDEWEB)

    Mouchtouri, Varvara A., E-mail: mouchtourib@med.uth.gr [Department of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, Larissa (Greece); Bartlett, Christopher L.R. [University College London, Centre for Infectious Disease Epidemiology Department of Primary Care and Population Sciences Royal Free and University College Medical School, London (United Kingdom); Diskin, Arthur [Royal Caribbean Cruise Line, Miami (United States); Hadjichristodoulou, Christos [Department of Hygiene and Epidemiology, Faculty of Medicine, University of Thessaly, Larissa (Greece)

    2012-07-01

    Background: Legionella spp. and other waterborne pathogens have been isolated from various water systems on land based premises as well as on ships and cases of Legionnaires' disease have been associated with both sites. Peculiarities of cruise ships water systems make the risk management a challenging process. The World Health Organization suggests a Water Safety Plan (WSP) as the best approach to mitigate risks and hazards such as Legionella spp. and others. Objectives: To develop WSP on a cruise ship and discuss challenges, perspectives and key issues to success. Methods: Hazards and hazardous events were identified and risk assessment was conducted of the ship water system. Ship company management, policies and procedures were reviewed, site visits were conducted, findings and observations were recorded and discussed with engineers and key crew members were interviewed. Results: A total of 53 hazards and hazardous events were taken into consideration for the risk assessment and additional essential barriers were established when needed. Most of them concerned control measures for biofilm development and Legionella spp. contamination. A total of 29 operational limits were defined. Supplementary verification and supportive programs were established. Conclusions: Application of the WSP to ship water systems, including potable water, recreational water facilities and decorative water features and fountains, is expected to improve water management on ships. The success of a WSP depends on support from senior management, commitment of the Captain and crew members, correct execution of all steps of a risk assessment and practicality and applicability in routine operation. The WSP provides to shipping industry a new approach and a move toward evidence based water safety policy. - Highlights: Black-Right-Pointing-Pointer We conducted risk assessment and developed a Water Safety Plan on a cruise ship. Black-Right-Pointing-Pointer 53 hazards and hazardous events were

  19. The impact of meteorology on the occurrence of waterborne outbreaks of vero cytotoxin-producing Escherichia coli (VTEC): a logistic regression approach.

    Science.gov (United States)

    O'Dwyer, Jean; Morris Downes, Margaret; Adley, Catherine C

    2016-02-01

    This study analyses the relationship between meteorological phenomena and outbreaks of waterborne-transmitted vero cytotoxin-producing Escherichia coli (VTEC) in the Republic of Ireland over an 8-year period (2005-2012). Data pertaining to the notification of waterborne VTEC outbreaks were extracted from the Computerised Infectious Disease Reporting system, which is administered through the national Health Protection Surveillance Centre as part of the Health Service Executive. Rainfall and temperature data were obtained from the national meteorological office and categorised as cumulative rainfall, heavy rainfall events in the previous 7 days, and mean temperature. Regression analysis was performed using logistic regression (LR) analysis. The LR model was significant (p < 0.001), with all independent variables: cumulative rainfall, heavy rainfall and mean temperature making a statistically significant contribution to the model. The study has found that rainfall, particularly heavy rainfall in the preceding 7 days of an outbreak, is a strong statistical indicator of a waterborne outbreak and that temperature also impacts waterborne VTEC outbreak occurrence.

  20. Surveillance for waterborne disease and outbreaks associated with drinking water and water not intended for drinking-United States, 2005-2006

    Science.gov (United States)

    PROBLEM/CONDITION: Since 1971, CDC, the U.S. Environmental Protection Agency (EPA), and the Council of State and Territorial Epidemiologists have maintained a collaborative Waterborne Disease and Outbreak Surveillance System (WBDOSS) for collecting and reporting data related to o...

  1. Measuring water-borne cortisol in Poecilia latipinna:is the process stressful, can stress be minimized and is cortisol correlated with sex steroid release rates?

    Science.gov (United States)

    Gabor, C R; Contreras, A

    2012-09-01

    The stress of water-borne hormone collection process was examined in sailfin mollies Poecilia latipinna. Baseline release rates of the stress hormone cortisol were measured and minimum confinement time for water sampling was evaluated for a standard 60 min v. a 30 min protocol. A 30 min hormone collection period reflects release rates over 60 min. Potential stress response to confinement in the beaker for the water-borne collection process was tested over 4 days. There was no evidence of stress due to the collection methods, as cortisol release rates did not differ significantly across four sequential days of handling for P. latipinna. Males and females did not differ significantly in baseline cortisol release rates. Baseline cortisol release rates from fish immediately after being collected in the field were also not significantly different than those in the 4 day confinement experiment. After exposure to a novel environment, however, P. latipinna mounted a stress response. Stress may also affect sex steroids and behaviour but cortisol release rates were not significantly correlated with sex steroids [11-ketotestosterone (KT), testosterone, or oestradiol], or mating attempts. The correlation between water-borne release rates and plasma steroid levels was validated for both cortisol and KT. Finally, normalizing cortisol release rates using standard length in lieu of mass is viable and accurate. Water-borne hormone assays are a valuable tool for investigating questions concerning the role of hormones in mediating stress responses and reproductive behaviours in P. latipinna and other livebearing fishes.

  2. Risk of Handling as a Route of Exposure to Infectious Waterborne Cryptosporidium parvum Oocysts via Atlantic Blue Crabs (Callinectes sapidus)▿

    Science.gov (United States)

    Graczyk, Thaddeus K.; McOliver, Cynthia; Silbergeld, Ellen K.; Tamang, Leena; Roberts, Jennifer D.

    2007-01-01

    Commercial Atlantic blue crabs (Callinectes sapidus) were exposed to 2.0 × 104 infectious waterborne oocysts of Cryptosporidium parvum. The study demonstrated that blue crabs can transfer C. parvum oocysts to persons involved in handling or preparing crabs and that they may contaminate other surfaces or products during storage. PMID:17449680

  3. A survey of diving behaviour and accidental water ingestion among Dutch occupational and sport divers to assess the risk of infection with waterborne pathogenic microorganisms.

    NARCIS (Netherlands)

    Schijven, Jack; Roda Husman, Ana Maria de

    2006-01-01

    Divers may run a higher risk of infection with waterborne pathogens than bathers because of more frequent and intense contact with water that may not comply with microbiologic water quality standards for bathing water. In this study we aimed to estimate the volume of water swallowed during diving as

  4. Research progress of acrylate modified waterborne polyurethane%丙烯酸酯改性水性聚氨酯的研究进展

    Institute of Scientific and Technical Information of China (English)

    高国生; 任筱芳; 杜郢; 蔡小燕

    2012-01-01

    介绍了丙烯酸酯改性水性聚氨酯乳液(PUA)的制备方法,其中包括乳液型丙烯酸酯改性水性聚氨酯、单体丙烯酸酯改性水性聚氨酯、溶剂型丙烯酸酯低聚物改性水性聚氨酯,指出了各改性方法的优缺点;概述了国内外的研究现状,对丙烯酸酯改性水性聚氨酯前景进行了展望.%In this paper.the preparation methods of acrylate modified waterborne polyurethanes (PUA) were fully reviewed.including the acrylic emulsion modified waterborne polyurethane.the acrylic monomer modified waterborne polyurethane and the solvent-based acrylic oligomer modified waterborne polyurethane. On the basis of the advantages and disadvantages of these methods and the overseas and domestic research situation,the prospects of PUA was discussed.

  5. Development of Waterborne Two Component Polyurethane Exterior Wall Overcoat Varnish%水性双组分聚氨酯外墙罩光清漆的研制

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Combining the good pro coatings, waterborne two component perti PU es of solvent based two component PU coatings with low VOC of waterborne coatings has been being the research hotspot and development direction. The waterborne two component polyurethane exterior wall overcoat varnish with excellent film properties and very low VOC was prepared with core-shell hydroxyl acrylic emulsion as the chief film forming matter and waterborne polyisocyanate as curing agent.%水性双组分聚氨酯涂料兼有溶剂型双组分聚氨酯涂料的高性能和水性涂料的低VOC(挥发性有机化合物)特点,成为当前涂料研究的热点和发展方向。以核壳结构的羟基丙烯酸乳液为主要成膜物质,以水性异氰酸酯为固化剂,制得水性双组分聚氨酯外墙罩光清漆,所得涂膜性能优异且VOC含量极低。

  6. 改性水性聚氨酯胶黏剂研究进展%Progress of modification of waterborne polyurethane adhesive

    Institute of Scientific and Technical Information of China (English)

    邓威; 黄洪; 傅和青

    2011-01-01

    The classification and preparation of waterborne polyurethane adhesive are introduced. The modification methods of waterborne polyurethane, such as acrylate modification, epoxy resin modification, organic fluorine modification, silicone, nanomaterials modification, multi-modification and hyperbranched prepolymer modification are summarized. The advantages and disadvantages of these modification methods are compared, and the application of the modified waterborne polyurethane adhesive is proposed. The development of waterborne polyurethane adhesive is discussed.%介绍了水性聚氨酯胶黏剂的分类和合成方法.综述了水性聚氨酯的改性方法,包括丙烯酸酯改性、环氧树脂改性、有机氟改性、有机硅改性、纳米材料改性、复合改性和超支化预聚体改性.比较了各种改性方法的优势和缺陷,提出了每种方法改性的胶黏剂的适用领域,指出了水性聚氨酯胶黏剂的发展趋势.

  7. Research Progress on Nano-material modified Waterborne Polyurethane%纳米粉体材料改性水性聚氨酯的研究进展

    Institute of Scientific and Technical Information of China (English)

    赵凤艳; 杨大伟; 王全杰

    2011-01-01

    The present applications of nano powder materials in waterborne polyurethane were reviewed. The classification, characteristics and definition of nanometer materials were also discussed, besides the synthesis mechanism and methods of waterborne polyurethane compounding with nano powder materials. It emphasized the progress of nanometer materials in modifying water-borne polyurethane. At last the prospects of the application of nanometer materials in waterborne polyurethane were put forward.%综述了纳米粉体材料在水性聚氨酯中的应用现状,针对纳米材料的分类、特点和定义进行了阐述,以及与水性聚氨酯的作用机理和合成方法。着重介绍了纳米材料在改性水性聚氨酯中的研究进展,并对纳米材料在水性聚氨酯中的应用前景提出展望。

  8. 共聚改性水性聚氨酯的研究进展%Progress of copolymerization modification of waterborne polyurethanes

    Institute of Scientific and Technical Information of China (English)

    张探; 王晓莉; 卢曼怡; 熊晓; 孔志祥; 张洋; 管蓉

    2015-01-01

    共聚改性水性聚氨酯 WPU 可以有效的提高其耐热性、耐水性和力学性能,并且能够很好的将共聚材料与WPU的优点结合起来。本文重点介绍了环氧树脂、丙烯酸酯、有机硅和有机氟共聚改性WPU的研究进展,并对共聚改性WPU的发展现状进行了分析和展望。()%The copolymerization modification of waterborne polyurethanes combining the advantages of copolymerized materials and waterborne polyurethanes(WPU) can improve their heat resistance, water resistance and mechanical properties. This paper introduced the progress of copolymerization modification of waterborne polyurethanes epoxy resin, acrylate, silicone and organic fluorine with at home and abroad in recent years. Finally, current development situation and the trend of copolymerization modification waterborne polyurethanes were analyzed and prospected.

  9. Comparing the relative importance of water-borne cues and direct grazing for the induction of defenses in the brown seaweed Fucus vesiculosus.

    Science.gov (United States)

    Flöthe, Carla R; John, Uwe; Molis, Markus

    2014-01-01

    Some seaweed species have been shown to release water-borne cues after herbivore attack, for example, to attract natural enemies of the herbivore. These cues may also be sensed by neighboring seaweeds and used to adjust their defenses in anticipation of a possible herbivore attack. Several studies indicated information transfer between seaweed individuals in the past, including the brown seaweed Fucus vesiculosus. Previous work showed induction of defenses in F. vesiculosus in response to water-borne cues released by isopod-grazed conspecifics. In contrast, another study on induced responses after exposure to cues from isopod-grazed neighbors using the same seaweed species yielded contradictory results. This study reassessed the ability of F. vesiculosus individuals to sense water-borne cues released by isopod-grazed neighbors in a series of experiments that monitored F. vesiculosus palatability in response to direct grazing by Idotea baltica and water-borne cues from isopod-grazed neighbors relative to unmanipulated seaweed pieces. Two-choice feeding assays were conducted with both fresh and reconstituted seaweed pieces. Direct grazing by I. baltica induced a chemical defense in F. vesiculosus, confirming results of previous studies. In contrast, evidence for increased herbivore resistance in seaweed pieces that were located downstream of isopod-grazed F. vesiculosus could not be provided. The lack of defense induction in response to grazing of conspecific neighbors may be explained by the environmental conditions and the scattered distribution of F. vesiculosus individuals in the intertidal zone of Helgoland, which may render resource investment in the emission and/or response to water-borne cues at this site unprofitable.

  10. Comparing the relative importance of water-borne cues and direct grazing for the induction of defenses in the brown seaweed Fucus vesiculosus.

    Directory of Open Access Journals (Sweden)

    Carla R Flöthe

    Full Text Available Some seaweed species have been shown to release water-borne cues after herbivore attack, for example, to attract natural enemies of the herbivore. These cues may also be sensed by neighboring seaweeds and used to adjust their defenses in anticipation of a possible herbivore attack. Several studies indicated information transfer between seaweed individuals in the past, including the brown seaweed Fucus vesiculosus. Previous work showed induction of defenses in F. vesiculosus in response to water-borne cues released by isopod-grazed conspecifics. In contrast, another study on induced responses after exposure to cues from isopod-grazed neighbors using the same seaweed species yielded contradictory results. This study reassessed the ability of F. vesiculosus individuals to sense water-borne cues released by isopod-grazed neighbors in a series of experiments that monitored F. vesiculosus palatability in response to direct grazing by Idotea baltica and water-borne cues from isopod-grazed neighbors relative to unmanipulated seaweed pieces. Two-choice feeding assays were conducted with both fresh and reconstituted seaweed pieces. Direct grazing by I. baltica induced a chemical defense in F. vesiculosus, confirming results of previous studies. In contrast, evidence for increased herbivore resistance in seaweed pieces that were located downstream of isopod-grazed F. vesiculosus could not be provided. The lack of defense induction in response to grazing of conspecific neighbors may be explained by the environmental conditions and the scattered distribution of F. vesiculosus individuals in the intertidal zone of Helgoland, which may render resource investment in the emission and/or response to water-borne cues at this site unprofitable.

  11. Biokinetic food chain modeling of waterborne selenium pulses into aquatic food chains: Implications for water quality criteria.

    Science.gov (United States)

    DeForest, David K; Pargee, Suzanne; Claytor, Carrie; Canton, Steven P; Brix, Kevin V

    2016-04-01

    We evaluated the use of biokinetic models to predict selenium (Se) bioaccumulation into model food chains after short-term pulses of selenate or selenite into water. Both periphyton- and phytoplankton-based food chains were modeled, with Se trophically transferred to invertebrates and then to fish. Whole-body fish Se concentrations were predicted based on 1) the background waterborne Se concentration, 2) the magnitude of the Se pulse, and 3) the duration of the Se pulse. The models were used to evaluate whether the US Environmental Protection Agency's (USEPA's) existing acute Se criteria and their recently proposed intermittent Se criteria would be protective of a whole-body fish Se tissue-based criterion of 8.1 μg g(-1) dry wt. Based on a background waterborne Se concentration of 1 μg L(-1) and pulse durations of 1 d and 4 d, the Se pulse concentrations predicted to result in a whole-body fish Se concentration of 8.1 μg g(-1) dry wt in the most conservative model food chains were 144 and 35 μg L(-1), respectively, for selenate and 57 and 16 μg L(-1), respectively, for selenite. These concentrations fall within the range of various acute Se criteria recommended by the USEPA based on direct waterborne toxicity, suggesting that these criteria may not always be protective against bioaccumulation-based toxicity that could occur after short-term pulses. Regarding the USEPA's draft intermittent Se criteria, the biokinetic modeling indicates that they may be overly protective for selenate pulses but potentially underprotective for selenite pulses. Predictions of whole-body fish Se concentrations were highly dependent on whether the food chain was periphyton- or phytoplankton-based, because the latter had much greater Se uptake rate constants. Overall, biokinetic modeling provides an approach for developing acute Se criteria that are protective against bioaccumulation-based toxicity after trophic transfer, and it is also a useful tool for evaluating averaging

  12. Modeling Leptospirosis in Trinidad, West Indies: A Waterborne Zoonosis of Increasing Public Health Importance

    Science.gov (United States)

    Vega, M. C.; Opadeyi, J.

    2012-12-01

    Leptospirosis is a waterborne disease which is considered one of the most common and widely spread bacterial zoonosis and a growing global public health problem. Transmission in humans is caused by direct or indirect contact with contaminated water, soil or infected urine, blood or tissue of carrier animals. Because of the similarity with influenza, dengue and viral hepatitis symptoms it is often misdiagnosed with these diseases, but as the leptospirosis progresses, internal organs can be compromised, causing severe syndromes (e.g. Weil's disease), and potentially can cause death. In less developed countries, leptospirosis is often poorly recognized. In humid tropics and subtropics, where this disease has a high impact, climatic and environmental factors, such as rainfall, floods, land cover and their modifications have been frequently related to the occurrence of leptospirosis. In these regions one of the main problems for the study of the role of environmental factors on disease dynamics is the lack of accurate data since, in many cases, data are either unavailable or do not exist at all. Between 1980 and 2005 a total of 12,475 cases of leptospirosis were reported from all Caribbean countries, with 2,370 (19%) of these corresponding to Trinidad and Tobago, where the current average annual incidence rate is 1.84 per 100,000 population based on confirmed cases. In order to explore the underlying spatial variability of leptospirosis occurrence as related to environmental and socio-economic factors, a series of Geographically Weighted Regression (GWR) models were developed. GWR was used to examine the determinants of leptospirosis in the communities of Trinidad using a total of 1,549 reported cases and 250 confirmed cases from 1998 to 2008. MODIS satellite imagery and GIS analysis were used to develop a series of covariables for each community including land cover, vegetation indices, wetness index (ln (α/tanβ)), river length per Ha, topography, percentage of free

  13. Climate Change and Waterborne Diarrhoea in Northern India: Impact and Adaptation Strategies

    Science.gov (United States)

    Moors, Eddy; Singh, Tanya; Siderius, Christian; Balakrishnan, Sneha; Mishra, Arabinda

    2013-04-01

    Although some studies showed the vulnerability of human health to climate change (e.g. 22.000 to 45.000 excess mortality cases during the heat waves in Europe, or the association of malaria outbreaks with El Niño) a clear quantification of the increased risks attributable to climate change is often lacking. Even more complicated are the assessments of the adaptation measures for this sector. Adaptation measures are in most cases very site specific. We discuss the impact of climate change on diarrhoea as a representative of waterborne disease affecting human health in the Ganges basin of Northern India. India is by far the leading country when it comes to child mortality under five years caused by diarrhoea and accounted for 386.600 deaths in 2007. Estimates on the increased risk of diarrhoea as a result of increased temperature in the 2030ies range between 8-11%. Uncertainties around these estimates mainly relate to the few studies that have characterized the exposure-response relationship and inter-model discrepancy of climate models. The influence of other climate parameters than temperature on diarrhoea in the future has not been assessed. As empirical studies and surveillance data for India are lacking we developed a conceptual framework for climate exposure-response relationships based on a literature review and applied it to future climate projections for the Ganges basin. Four climate variables are analysed: temperature, increased/extreme precipitation, decreased precipitation/droughts and relative humidity. In an analysis of reports on diarrhoea outbreaks we show the spatial and temporal distribution over the subcontinent. Most cases of diarrhoea occur during the hot summer (23%) and the wet and humid monsoon (57%) months. These reports often suggest sewage and pipe leakage as the leading cause of the local outbreaks. We demonstrate the applicability of the conceptual framework for the two districts in West Bengal, North and South 24 Parganas. All climate

  14. Synthesis and Characterization of Waterborne Epoxy Curing Agent Modified by Silane%有机硅改性水性环氧固化剂的合成及表征

    Institute of Scientific and Technical Information of China (English)

    卢光岐; 孙建中; 周其云

    2007-01-01

    A novel waterborne epoxy curing agent was prepared using 3-glycidoxypropyl trimethoxysilane (GPTMS) as a termination agent of adduct,which was synthesized by triethylene tetramine (TETA) and liquid epoxy resin (E-51). The effects of the reaction temperature and time on the synthesis process were investigated experimentally. The particle size and the distribution of water dispersion of the curing agent were measured by dynamic light scattering (DLS). The structure of the products was characterized by Fourier transform infrared spectrometer (FTIR) and 1H-nuclear magnetic resonance (1H NMR). The properties of the synthesized curing agent and the epoxy resin film cured by it were also measured. The results showed that the appropriate temperature for the synthesis of adduct was at 65-75 ℃ and the reaction time was 4-5 h,and that the suitable reaction temperature of curing agent synthesis was 75-85 ℃ and the reaction time was 3-4 h. When the mass ratios of GPTMS and acetic acid were 3%-5% and 5%-10% respectively,the hardness,water resistance and adhesion of the cured film were improved significantly.

  15. Ultrastructural effects on gill, muscle, and gonadal tissues induced in zebrafish (Danio rerio) by a waterborne uranium exposure

    Energy Technology Data Exchange (ETDEWEB)

    Barillet, Sabrina, E-mail: sabrina.barillet@free.fr [Laboratory of Radioecology and Ecotoxicology, IRSN (Institute for Radiological Protection and Nuclear Safety), DEI/SECRE/LRE, Cadarache, Bat 186, BP 3, 13115 St-Paul-Lez-Durance cedex (France); Larno, Valerie, E-mail: valerie.larno@irsn.fr [Laboratory of Radioecology and Ecotoxicology, IRSN (Institute for Radiological Protection and Nuclear Safety), DEI/SECRE/LRE, Cadarache, Bat 186, BP 3, 13115 St-Paul-Lez-Durance cedex (France); Floriani, Magali, E-mail: magali.floriani@irsn.fr [Laboratory of Radioecology and Ecotoxicology, IRSN (Institute for Radiological Protection and Nuclear Safety), DEI/SECRE/LRE, Cadarache, Bat 186, BP 3, 13115 St-Paul-Lez-Durance cedex (France); Devaux, Alain, E-mail: alain.devaux@entpe.fr [INRA, EFPA Department, 54280, Champenoux and Environmental Science Laboratory, ENTPE, 69518 Vaulx en Velin cedex (France); Adam-Guillermin, Christelle, E-mail: christelle.adam-guillermin@irsn.fr [Laboratory of Radioecology and Ecotoxicology, IRSN (Institute for Radiological Protection and Nuclear Safety), DEI/SECRE/LRE, Cadarache, Bat 186, BP 3, 13115 St-Paul-Lez-Durance cedex (France)

    2010-11-01

    Experiments on adult zebrafish (Danio rerio) were conducted to assess histopathological effects induced on gill, muscle, and gonadal tissues after waterborne uranium exposure. Although histopathology is often employed as a tool for the detection and assessment of xenobiotic-mediated effects in aquatic organisms, few studies have been dedicated to the investigation of histopathological consequences of uranium exposure in fish. Results showed that gill tissue architecture was markedly disrupted. Major symptoms were alterations of the secondary lamellae epithelium (from extensive oedema to desquamation), hyperplasia of chloride cells, and breakdown of the pillar cell system. Muscle histology was also affected. Degeneration and disorganization of myofibrillar sarcomeric pattern as well as abnormal localization of mitochondria within muscle and altered endomysial sheaths were observed. Morphological alterations of spermatozoa within the gonadal tissue were also noticed. This study demonstrated that uranium exposure induced a variety of histological impairments in fish, supporting environmental concerns when uranium contaminates aquatic systems.

  16. Tolerance of Physocypria kraepelini (Crustacean, Ostracoda) to water-borne ammonia, phosphate and pH value

    Institute of Scientific and Technical Information of China (English)

    YU Na; CHEN Shimei; LI Erchao; CHEN Jiayan; CHEN Liqiao

    2009-01-01

    This study evaluated the median lethal concentration (LC_(50)) and safe concentration of water-borne ammonia,phosphate and pH value on Physocypria kraepelini,a freshwater Ostracoda with a static renewal test system.The results indicated that the LC_(50) values of ammonia for P.kraepelini were 1026.71,859.98,771.79 and 583.82 mg/L at 24,48,72 and 96 h exposure,respectively,and the safe concentration range of ammonia for the long-term survival of P.kraepelini was less than 58.38 mg/L.Finally,the safe range of pH value for the survival of P.kraepelini was from 6.59 to 7.61.P.kraepelini has a high tolerance to ammonia,phosphate and pH value which are the main environmental factors in the serious eutrophication water.

  17. Electrochemical synthesis of multi-armed CuO nanoparticles and their remarkable bactericidal potential against waterborne bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Pratibha, E-mail: rkpratibha@yahoo.com; Merwyn, S.; Agarwal, G. S.; Tripathi, B. K.; Pant, S. C. [Defence Research and Development Establishment (India)

    2012-01-15

    Copper (II) oxide multi-armed nanoparticles composed of 500-1000 nm long radiating nanospicules with 100-200 nm width near the base and 50-100 nm width at the tapered ends and {approx}25 nm thickness were synthesized by electrochemical deposition in the presence of an oxidant followed by calcination at 150 Degree-Sign C. The nanoparticles were characterized using SEM/EDX for morphology and composition, Raman spectroscopy for compound identification, and broth culture method for antibacterial efficacy. The CuO nanoparticles have shown remarkable bactericidal efficacy against Gram-positive and -negative waterborne disease causing bacteria like Escherichia coli, Salmonella typhi, staphylococcus aureus and Bacillus subtilis. E. coli has been chosen as representative species for waterborne disease causing bacteria. In antibacterial tests 500 {mu}g/mL nano CuO killed 3 Multiplication-Sign 10{sup 8} CFU/mL E. coli bacteria within 4 h of exposure. Moreover, 8.3 Multiplication-Sign 10{sup 6} CFU/mL E. coli were killed by 100 and 10 {mu}g/mL nano CuO within 15 min and 4 h of exposure, respectively. Antibacterial activity of nano CuO has been found many-fold compared with commercial bulk CuO. The fate of nanoparticles after antibacterial test has also been studied. The synthesized CuO nanoparticles are expected to have potential antibacterial applications in water purification and in paints and coatings used on frequently touched surfaces and fabrics in hospital settings.

  18. Dose-related carcinogenic effects of water-borne benzo(a)pyrene on livers of two small fish species

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, W.E.; Walker, W.W.; Overstreet, R.M.; Lytle, T.F.; Lytle, J.S.

    1988-12-01

    Benzo(a)pyrene (BaP) administered by water-borne exposures caused dose-related carcinogenic effects in livers of two small fish species, the Japanese medaka (Oryzias latipes) and the guppy (Poecilia reticulata). Medaka and guppies each were given two 6-h exposures. The first exposure was conducted on 6- to 10-day-old specimens. The second exposure was given 7 days later. The tests incorporated five treatment groups: (1) control, (2) carrier (dimethylformamide) control, (3) low BaP dose (not detectable--4 ppb), (4) intermediate BaP dose (about 8-47 ppb BaP), and (5) high BaP dose (200-270 ppb). Following the high-dose exposure, hepatocellular lesions classified as foci of cellular alteration (altered foci), adenomas, and hepatocellular carcinomas occurred in both species. In medaka, the lesions appeared to develop sequentially with the appearance of altered foci followed by adenomas and then hepatocellular carcinomas. Most lesions in guppies, however, were classified as altered foci although a few adenomas occurred in the early (24-week) sample and hepatocellular carcinomas occurred in the late (52-week) sample. When total lesions were combined, medaka had an 11% incidence at 24 weeks after the initial exposure and 36% incidence at 36 weeks. In guppies, 8% had liver lesions at 24 weeks, 19% at 36 weeks, and 20% at 52 weeks. A single extrahepatic neoplasm, a capillary hemangioma in a gill filament, occurred in a medaka from the 36-week high-dose sample. The results suggest that the medaka and guppy are capable of metabolizing water-borne BaP to carcinogenic metabolites which initiate hepatic tumor development.

  19. Use of a passive bioreactor to reduce water-borne plant pathogens, nitrate, and sulfate in greenhouse effluent.

    Science.gov (United States)

    Gruyer, Nicolas; Dorais, Martine; Alsanius, Beatrix W; Zagury, Gérald J

    2013-01-01

    The goal of this study was to evaluate the use of passive bioreactors to reduce water-borne plant pathogens (Pythium ultimum and Fusarium oxysporum) and nutrient load (NO(-) 3 and SO(2-) 4) in greenhouse effluent. Sterilized and unsterilized passive bioreactors filled with a reactive mixture of organic carbon material were used in three replicates. After a startup period of 2 (sterilized) or 5 (unsterilized) weeks, the bioreactor units received for 14 weeks a reconstituted commercial greenhouse effluent composed of 500 mg L(-1) SO(2-) 4 and 300 mg L(-1) NO(-) 3 and were inoculated three times with P. ultimum and F. oxysporum (10(6) CFU mL(-1)). Efficacy in removing water-borne plant pathogens and nitrate reached 99.9% for both the sterilized and unsterilized bioreactors. However, efficacy in reducing the SO(2-) 4 load sharply decreased from 89% to 29% after 2 weeks of NO(-) 3-supply treatment for the unsterilized bioreactors. Although SO(2-) 4 removal efficacy for the sterilized bioreactors did not recover after 4 weeks of NO(-) 3-supply treatment, the unsterilized bioreactor nearly reached a similar level of SO(2-) 4 removal after 4 weeks of NO(-) 3-supply treatment compared with affluent loaded only with SO(2-) 4, where no competition for the carbohydrate source occurred between the denitrification process and sulfate-reducing bacteria activity. Performance differences between the sterilized and unsterilized bioreactors clearly show the predominant importance of sulfate-reducing bacteria. Consequently, when sulfate-reducing bacteria reach their optimal activity, passive bioreactors may constitute a cheap, low-maintenance method of treating greenhouse effluent to recycle wastewater and eliminate nutrient runoff, which has important environmental impacts.

  20. Determining the 95% limit of detection for waterborne pathogen analyses from primary concentration to qPCR

    Science.gov (United States)

    Stokdyk, Joel P.; Firnstahl, Aaron; Spencer, Susan K.; Burch, Tucker R; Borchardt, Mark A.

    2016-01-01

    The limit of detection (LOD) for qPCR-based analyses is not consistently defined or determined in studies on waterborne pathogens. Moreover, the LODs reported often reflect the qPCR assay alone rather than the entire sample process. Our objective was to develop an approach to determine the 95% LOD (lowest concentration at which 95% of positive samples are detected) for the entire process of waterborne pathogen detection. We began by spiking the lowest concentration that was consistently positive at the qPCR step (based on its standard curve) into each procedural step working backwards (i.e., extraction, secondary concentration, primary concentration), which established a concentration that was detectable following losses of the pathogen from processing. Using the fraction of positive replicates (n = 10) at this concentration, we selected and analyzed a second, and then third, concentration. If the fraction of positive replicates equaled 1 or 0 for two concentrations, we selected another. We calculated the LOD using probit analysis. To demonstrate our approach we determined the 95% LOD for Salmonella enterica serovar Typhimurium, adenovirus 41, and vaccine-derived poliovirus Sabin 3, which were 11, 12, and 6 genomic copies (gc) per reaction (rxn), respectively (equivalent to 1.3, 1.5, and 4.0 gc L−1 assuming the 1500 L tap-water sample volume prescribed in EPA Method 1615). This approach limited the number of analyses required and was amenable to testing multiple genetic targets simultaneously (i.e., spiking a single sample with multiple microorganisms). An LOD determined this way can facilitate study design, guide the number of required technical replicates, aid method evaluation, and inform data interpretation.

  1. Effects of exposure to high concentrations of waterborne Tl on K and Tl concentrations in Chironomus riparius larvae.

    Science.gov (United States)

    Belowitz, Ryan; Leonard, Erin M; O'Donnell, Michael J

    2014-11-01

    Thallium (Tl) is a non-essential metal which is released into the environment primarily as the result of anthropogenic activities such as fossil fuel burning and smelting of ores. The ionic radius of monovalent Tl⁺ is similar to that of K⁺ and Tl⁺ may thus interfere with K⁺-dependent processes. We determined that the acute (48 h) lethal concentration where 50% of the organisms do not survive (LC₅₀) of Tl for 4th instar Chironomus riparius larvae was 723 μmol L⁻¹. Accumulation of Tl by the whole animal was saturable, with a maximum accumulation (Jmax) of 4637 μmol kg⁻¹ wet mass, and K(D) of 670 μmol Tl l⁻¹. Tl accumulation by the gut appeared saturable at the lowest four Tl concentrations, with a Jmax of 2560 μmol kg⁻¹ wet mass and a K(D) of 54.5 μmol Tl l⁻¹. The saturable accumulation at the gut may be indicative of a limited capacity for intracellular detoxification, such as storage in lysosomes or complexation with metal-binding proteins. Tl accumulation by the hemolymph was found to be linear and Tl concentrations in the hemolymph were ~75% of the exposure concentration at Tl exposures >26.9 μmol L⁻¹. There was not a significant decrease in whole animal, gut or hemolymph K during exposure to waterborne Tl at any of the concentrations tested (up to 1500 μmol L⁻¹). The avoidance of hypokalemia by C. riparius larvae may contribute to survival during acute waterborne exposures to Tl. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Temporal dynamics of epidermal responses of guppies Poecilia reticulata to a sublethal range of waterborne zinc concentrations.

    Science.gov (United States)

    Gheorghiu, C; Marcogliese, D J; Scott, M E

    2009-12-01

    This study assessed the histological changes in the epidermis of guppies Poecilia reticulata induced by waterborne zinc (Zn). Laboratory-reared P. reticulata fry were maintained individually in separate vessels containing artificial water (8 microg l(-1) Zn) to which 0, 15, 30, 60 or 120 microg l(-1) Zn was added. Their epidermal response to Zn was monitored regularly over 4 weeks. Compared with controls, mucus was rapidly released and mucous cell numbers decreased at all concentrations. Thereafter mucous release, epidermal thickness, numbers and size of mucous cells fluctuated at a rate that varied with Zn concentration, but fluctuations declined after day 18. Results clearly highlight the dynamic nature of the epidermal response to sublethal concentrations of waterborne Zn. In general, low concentrations of Zn induced a rapid response with reduced numbers and size of mucous cells and shift in mucin composition, and a subsequent thickening of the epidermis. Epidermal thickness and mucous cell area fluctuated over time but were normal after a month of exposure to low Zn concentrations. The number of mucous cells, however, remained low. Virtually all mucous cells from fish maintained in 15 and 60 microg l(-1) Zn contained acidic mucins throughout the month, whereas fish maintained at 30 microg l(-1) Zn responded by production of neutral mucins during the first 12 days followed by a mixture of neutral and acidic mucins. At 120 microg l(-1) Zn, the most dramatic effects were the gradual but sustained decrease in numbers and area of mucous cells, and the shift to acidic mucins in these cells. Thus, as concentration of Zn increased, the epidermal responses indicated a disturbed host response (dramatic decline in mucous cell numbers, with mixed composition of mucins), which may have been less effective in preventing Zn uptake across the epithelium.

  3. Carbon particles

    Science.gov (United States)

    Hunt, Arlon J.

    1984-01-01

    A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

  4. Particle physics

    CERN Document Server

    Martin, Brian R

    2017-01-01

    An accessible and carefully structured introduction to Particle Physics, including important coverage of the Higgs Boson and recent progress in neutrino physics. Fourth edition of this successful title in the Manchester Physics series. Includes information on recent key discoveries including : An account of the discovery of exotic hadrons, beyond the simple quark model; Expanded treatments of neutrino physics and CP violation in B-decays; An updated account of ‘physics beyond the standard model’, including the interaction of particle physics with cosmology; Additional problems in all chapters, with solutions to selected problems available on the book’s website; Advanced material appears in optional starred sections.

  5. Research Progress on Nano Materials applied in Modified Waterborne Polyurethane%纳米材料在改性水性聚氨酯中的研究进展

    Institute of Scientific and Technical Information of China (English)

    曲家乐; 王全杰; 王玉洁

    2012-01-01

    The present applications of nano materials in waterborne polyurethane were reviewed, as well as the synthesis mechanism and methods of waterborne polyurethanecompounding with nano materials. The research progress of nano materials in modified waterborne polyurethane was mainly introduced. The application prospects of nano materials in waterborne polyurethane was proposed.%综述了纳米材料在水性聚氨酯中的应用现状,以及与该类水性聚氨酯的作用和合成方法。着重介绍了纳米材料在改性水性聚氨酯中的研究进展,并对纳米材料在水性聚氨酯中的应用前景提出展望。

  6. Progress of Waterborne Polyurethane and Its Application in Paper-making Industry%水性聚氨酯研究进展及在造纸工业中的应用

    Institute of Scientific and Technical Information of China (English)

    尚尉; 涂强; 孟晓敏; 孙墨杰

    2012-01-01

    该文主要从水性聚氨酯的发展现状、发展方向、水性聚氨酯改性、水性封闭型聚氨酯体系及其影响因素等几个方面论述了水性聚氨酯的研究进展情况;同时还综述了水性聚氨酯在造纸工业中的应用及其发展趋势。%The development of the waterborne polyurethane technology was reviewed including mainly its current situation,its future,modification of waterborne polyurethane,waterborne blocked polyurethane system and its influencing factors.The application of waterborne polyurethane and its development trend in paper-making industry were also summarized in this paper.

  7. Effects of Waterborne Cu and Cd on Anti-oxidative Response, Lipid Peroxidation and Heavy Metals Accumulation in AbaloneHaliotis discus hannai Ino

    Institute of Scientific and Technical Information of China (English)

    LEI Yanju; ZHANG Wenbing; XU Wei; ZHANG Yanjiao; ZHOU Huihui; MAI Kangsen

    2015-01-01

    The aim of this study was to compare the effects of waterborne copper (Cu) and cadmium (Cd) on survival, anti-oxida- tive response, lipid peroxidation and metal accumulation in abaloneHaliotis discus hannai. Experimental animals (initial weight: 7.49g±0.01g) were exposed to graded concentrations of waterborne Cu (0.02, 0.04, 0.06, 0.08mgL-1) or Cd (0.025, 0.05, 0.25, 0.5 mgL-1) for 28 days, respectively. Activities of the anti-oxidative enzymes (catalase, CAT; superoxide dismutase, SOD; glutathione peroxidases, GPx; glutathione S-transferase, GST), contents of the reduced glutathione (GSH) and malondiadehyde (MDA) in the hepatopancreas, and metal accumulation in hepatopancreas and muscles were analyzed after 0, 1, 3, 6, 10, 15, 21, 28 days of metal exposure, respectively. Results showed that 0.04mgL-1, 0.06mgL-1 and 0.08mgL-1 Cu caused 100% death of abalone on the 21st, 10th and 6th day, respectively. However, no dead abalone was found during the 28-day waterborne Cd exposure at all experimental concentrations. Generally, activities of SOD and GST in hepatopancreas under all Cu concentrations followed a decrease trend as the exposure time prolonged. However, these activities were firstly increased and then decreased to the control level and increased again during Cd exposure. Activities of CAT in all Cu exposure treatments were higher than those in the control. These activities were firstly increased and then decreased to the control level and increased again during Cd exposure. Contents of MDA in hepatopancreas in all Cu treatments significantly increased first and then decreased to the control level. However, the MDA contents in hepatopan-creas were not significantly changed during the 28-day Cd exposure. The metals accumulation in both hepatopancreas and muscles of abalone significantly increased with the increase of waterborne metals concentration and exposure time. These results indicated that H. discus hannai has a positive anti-oxidative defense against Cu

  8. 浅谈防盗门制造业用水性转印清漆的制备%Discussion of Preparation of Waterborne Transfer Varnish Applied in the Manufacturing Industry of Security Doors

    Institute of Scientific and Technical Information of China (English)

    节昌澎

    2016-01-01

    Waterborne transfer varnish based on waterborne acrylic resin was prepared. The coatings could be applied on security doors and similar industries.%介绍了一种基于水性丙烯酸树脂的水性转印清漆的制备方法,主要可应用于防盗门制造业及类似工艺产品转移印后的表面涂装涂饰。

  9. 辐照水性聚氨酯的复合改性研究与应用进展%Progress in Modification and Application of Radiation Waterborne Polyurethane

    Institute of Scientific and Technical Information of China (English)

    杨蓓蓓; 杨建军; 吴庆云; 张建安; 吴明元

    2012-01-01

    Irradiated waterborne polyurethane mainly included gamma-irradiation rays (Co-60 ) irradiated WPU and ultraviolet (UV) curing WPU, and several multi-modified methods were summarized for radiation waterborne polyurethane. Weather resistance and mechanical properties of radiation waterborne polyurethane were superior to those of waterborne polyurethane, so radiation waterborne polyurethane could be used in the field of printing adhesive, floor paint, wood coating, automotive top coats. In the end, the development prospects of radiation water-borne polyurethane were expected.%综述了辐照水性聚氨酯(WPU)最常用的多元改性方法,重点介绍了γ射线(Co-60)辐照WPU和紫外光(UV)固化WPU的改性方法.改性后的辐照WPU的耐候性和机械性能要远优于WPU,辐照WPU经改性后可应用于印花粘合剂、地板涂料、木器漆涂料和汽车漆膜等领域.最后展望了辐照WPU的发展前景.

  10. Preparation and Properties of Acrylate Modified Non -ionic Waterborne Polyurethane%丙烯酸酯改性非离子型水性聚氨酯的合成及性能

    Institute of Scientific and Technical Information of China (English)

    饶舟; 戴震; 王焕; 许戈文

    2012-01-01

    A non - ionic waterborne polyurethane ( HPU) was synthesized using isophorone diisocyanate (IPDI) , polypropylene glycol (N-210) and polyethylene glycol (PEG) as the basic materials, and 2 -hydroxyethyl acrylate (HEA) as the end capping agent, Which was then polymerized with methyl methacry-late (MMA) and butyl acrylate ( BA) monomers by the thermally - initiated free radical polymerization to obtain the title product(PUA). The product(PUA) was characterized by water resistance test, particle size analysis, thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The experiment results showed that PUA displayed a core - shell structure, and the average particle size of PUA became lar-ger ; the water resistance of PUA films decreased with increase of HPU content, and the thermal stability of PUA films was improved greatly.%以异佛尔酮二异氰酸酯(IPDI)、聚氧化丙烯二醇(N-210)、聚氧化乙烯二醇(PEG)等为基本原料,丙烯酸羟乙酯(HEA)为封端剂,合成了非离子型双键封端水性聚氨酯(HPU)自乳化乳液,然后与甲基丙烯酸甲酯(MMA)及丙烯酸丁酯(BA)进行自由基聚合,得到丙烯酸酯改性非离子型水性聚氨酯(PUA)乳液.对这种材料进行了耐水性、粒径及热力学等方面的测试,结果表明:PUA乳液粒子有明显核壳结构,乳液的平均粒径增大;胶膜耐水性随着HPU添加量的提高而降低,胶膜的耐热性有明显提高.

  11. Particle physics

    CERN Document Server

    Kennedy, Eugene

    2012-01-01

    Stimulated by the Large Hadron Collider and the search for the elusive Higgs Boson, interest in particle physics continues at a high level among scientists and the general public. This book includes theoretical aspects, with chapters outlining the generation model and a charged Higgs boson model as alternative scenarios to the Standard Model. An introduction is provided to postulated axion photon interactions and associated photon dispersion in magnetized media. The complexity of particle physics research requiring the synergistic combination of theory, hardware and computation is described in terms of the e-science paradigm. The book concludes with a chapter tackling potential radiation hazards associated with extremely weakly interacting neutrinos if produced in copious amounts with future high-energy muon-collider facilities.

  12. Active particles

    CERN Document Server

    Degond, Pierre; Tadmor, Eitan

    2017-01-01

    This volume collects ten surveys on the modeling, simulation, and applications of active particles using methods ranging from mathematical kinetic theory to nonequilibrium statistical mechanics. The contributing authors are leading experts working in this challenging field, and each of their chapters provides a review of the most recent results in their areas and looks ahead to future research directions. The approaches to studying active matter are presented here from many different perspectives, such as individual-based models, evolutionary games, Brownian motion, and continuum theories, as well as various combinations of these. Applications covered include biological network formation and network theory; opinion formation and social systems; control theory of sparse systems; theory and applications of mean field games; population learning; dynamics of flocking systems; vehicular traffic flow; and stochastic particles and mean field approximation. Mathematicians and other members of the scientific commu...

  13. Particle astrophysics

    CERN Document Server

    Krauss, Lawrence M

    1997-01-01

    Astrophysics and cosmology provide fundamental testing grounds for many ideas in elementary particle physics, and include potential probes which are well beyond the range of current or even planned accelerators. In this series of 3 lectures, I will give and overview of existing constraints, and a discussion of the potential for the future. I will attempt whenever possible to demonstrate the connection between accelerator-based physics and astrophysicas/cosmology. The format of the kectures will be to examine observables from astrophysics, and explore how these can be used to constrain particle physics. Tentatively, lecture 1 will focus on the age and mass density of the universe and galaxy. Lecture 2 will focus on stars, stellar evolution, and the abundance of light elements. Lecture 3 will focus on various cosmic diffuse backgrounds, including possibly matter, photons, neutrinos and gravitational waves.

  14. Research Progress in Waterborne Polyurethane Modified with Organic Fluorine%有机氟改性水性聚氨酯的研究进展

    Institute of Scientific and Technical Information of China (English)

    张明月; 徐汉青

    2011-01-01

    着重介绍了近年来国内外有机氟改性水性聚氨酯的合成方法和性能,指出了这些合成工艺中尚存在的问题,并对问题作以简要分析。最后对有机氟改性水性聚氨酯的未来提出了展望。%Synthesis methods and properties of waterborne polyurethane modified by fluorine were introduced in this essay at home and abroad in recent years,and matters in these synthesis technologies were pointed out and analysed briefly.The prospects of waterborne polyurethane modified by fluorine were mentioned at last.

  15. 聚醚多元醇合成封端型水性聚氨酯乳液%Synthesis of waterborne blocked polyurethane emulsion based on polyether polyols

    Institute of Scientific and Technical Information of China (English)

    陡媛; 赵振河; 刘晶

    2015-01-01

    Using polyether triol and toluene diisocyanate as the basic raw materials, isopropanol as the diluent and sodium bisulfite as the blocking agent, the waterborne blocked polyurethane emulsion was synthesized. And the effects of isocyanate index (R value), temperature and time of prepolymerization, blocking agent amount and temperature and time of blocking on the properties of blocked waterborne polyurethane emulsion were analyzed and discussed.%以聚醚三元醇和甲苯二异氰酸酯(TDI)为基本原料,异丙醇为稀释剂,亚硫酸氢钠为封端剂制得水性聚氨酯。分析并讨论预聚温度和时间、R值、封端剂用量、封端温度及时间等因素对水性聚氨酯性能的影响。

  16. Modification of Waterborne Polyurethane Leather Finishing Agent%水性聚氨酯皮革涂饰剂的改性研究

    Institute of Scientific and Technical Information of China (English)

    靳园敏; 王鸿儒

    2011-01-01

    介绍了聚氨酯的结构及作为皮革涂饰剂的优越性能,综述了皮革用水性聚氨酯涂饰剂的改性研究,提出几种环保型新原料在水性聚氨酯皮革涂饰剂中的应用,并进一步简述了水性聚氨酯涂饰剂的发展趋势。%The structure and good performance of waterborne polyurethane as leather coating agent was summarized. Then a detailed description of the development of it's modification was given. Several environment - friendly raw materials which can be used in the synthesis of waterborne polyurethane were introduced. Furthermore, the development trend of water - based polyure-thane coating agent was prospected.

  17. 水性聚氨酯的改性研究进展%Research progress of modification technology for waterborne polyurethane

    Institute of Scientific and Technical Information of China (English)

    颜财彬; 傅和青

    2011-01-01

    The modification of waterborne polyurethane are summarized,including cross-linking modification,acrylate modification,epoxy resin modification,organic silicon modification,organic fluorine modification,nanomaterials modification,hyperbranched prepolymer modification and multi-modification.The methods and advantages of each modification technology are compared.The modification development of waterborne polyurethane is discussed.%综述了水性聚氨酯的改性,包括交联改性、丙烯酸酯改性、环氧树脂改性、有机硅改性、有机氟改性、纳米改性、超支化预聚体改性和复合改性。比较了不同改性技术的方法和优势,展望了水性聚氨酯的改性发展趋势。

  18. Particle encapsulation

    OpenAIRE

    Sun, Xiaobin

    2000-01-01

    Several engineering processes are powder based, ranging from food processing to engineering ceramic and composite production. In most of these processes, powders of different composition are mixed together in order to produce the final product, and this combining of powders of different density, shape, and surface properties is often very difficult. Mixtures may be quite inhomogeneous. This research focuses on a method of avoiding such problems, by coating individual particles of one material...

  19. Martian Particle

    Science.gov (United States)

    2008-01-01

    This image of Martian soil was taken by the Phoenix Lander's atomic force microscope on Sol 74 of the mission, which began on May 25, 2008. This image of a flat, smooth-surfaced particle is consistent with the appearance of soil from Earth containing the mineral phyllosilicate. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by JPL, Pasadena, Calif. Spacecraft development was by Lockheed Martin Space Systems, Denver.

  20. Food and water security issues in Russia III: food- and waterborne diseases in the Russian Arctic, Siberia and the Far East, 2000–2011

    Directory of Open Access Journals (Sweden)

    Alexey A. Dudarev

    2013-12-01

    Full Text Available Background . The food- and waterborne disease situation in Russia requires special attention. Poor quality of centralized water supplies and sewage systems, biological and chemical contamination of drinking water, as well as contamination of food products, promote widespread infectious diseases, significantly exceeding nationwide rates in the population living in the two-thirds of Russian northern territories. Objectives. The general aim was to assess the levels of food- and waterborne diseases in selected regions of Russian Arctic, Siberia and the Far East (for the period 2000–2011, and to compare disease levels among regions and with national levels in Russia. Study design and methods . This study is the first comparative assessment of the morbidity in these fields of the population of 18 selected regions of Russian Arctic, Siberia and the Far East, using official statistical sources. The incidences of infectious and parasitic food- and waterborne diseases among the general population (including indigenous peoples have been analyzed in selected regions (per 100,000 of population, averaged for 2000–2011. Results . Among compulsory registered infectious and parasitic diseases, there were high rates and widespread incidences in selected regions of shigellosis, yersiniosis, hepatitis A, tularaemia, giardiasis, enterobiasis, ascariasis, diphyllobothriasis, opistorchiasis, echinococcosis and trichinellosis. Conclusion . Incidences of infectious and parasitic food- and waterborne diseases in the general population of selected regions of the Russian Arctic, Siberia and the Far East (2000–2011 are alarmingly high. Parallel solutions must be on the agenda, including improvement of sanitary conditions of cities and settlements in the regions, modernization of the water supply and of the sewage system. Provision and monitoring of the quality of the drinking water, a reform of the general healthcare system and the epidemiological surveillance

  1. Food and water security issues in Russia III: food- and waterborne diseases in the Russian Arctic, Siberia and the Far East, 2000–2011

    Science.gov (United States)

    Dudarev, Alexey A.; Dorofeyev, Vitaliy M.; Dushkina, Eugenia V.; Alloyarov, Pavel R.; Chupakhin, Valery S.; Sladkova, Yuliya N.; Kolesnikova, Tatjana A.; Fridman, Kirill B.; Nilsson, Lena Maria; Evengard, Birgitta

    2013-01-01

    Background The food- and waterborne disease situation in Russia requires special attention. Poor quality of centralized water supplies and sewage systems, biological and chemical contamination of drinking water, as well as contamination of food products, promote widespread infectious diseases, significantly exceeding nationwide rates in the population living in the two-thirds of Russian northern territories. Objectives The general aim was to assess the levels of food- and waterborne diseases in selected regions of Russian Arctic, Siberia and the Far East (for the period 2000–2011), and to compare disease levels among regions and with national levels in Russia. Study design and methods This study is the first comparative assessment of the morbidity in these fields of the population of 18 selected regions of Russian Arctic, Siberia and the Far East, using official statistical sources. The incidences of infectious and parasitic food- and waterborne diseases among the general population (including indigenous peoples) have been analyzed in selected regions (per 100,000 of population, averaged for 2000–2011). Results Among compulsory registered infectious and parasitic diseases, there were high rates and widespread incidences in selected regions of shigellosis, yersiniosis, hepatitis A, tularaemia, giardiasis, enterobiasis, ascariasis, diphyllobothriasis, opistorchiasis, echinococcosis and trichinellosis. Conclusion Incidences of infectious and parasitic food- and waterborne diseases in the general population of selected regions of the Russian Arctic, Siberia and the Far East (2000–2011) are alarmingly high. Parallel solutions must be on the agenda, including improvement of sanitary conditions of cities and settlements in the regions, modernization of the water supply and of the sewage system. Provision and monitoring of the quality of the drinking water, a reform of the general healthcare system and the epidemiological surveillance (including gender

  2. 汽车水性双底色涂装工艺设计与研究%Painting Process Design and Study on Waterborne Auto Double Color Coatings

    Institute of Scientific and Technical Information of China (English)

    何小龙

    2012-01-01

    This paper introduces waterborne auto double color coating process characteristics, by contrast with the traditional waterborne 3C2B process, its advantages and disadvantages were analyzed, and the application prospect was elaborated. Combine with waterborne double color coating process characteristics and application examples which produced from main coatings supplier DuPont, BASF and PPG, respectively. The practical design and application of such technology in China automotive industry were analyzed.%详细介绍了水性双底色涂装工艺特性,通过与传统水性3C2B工艺的对比,分析其优缺点,阐述其应用前景,结合主要涂料供应商杜邦、巴斯夫和PPG各自水性双底色涂料的工艺特点和应用实例,分析此类工艺在我国汽车涂装中的实际设计和应用情况。

  3. Cytochrome P450 system expression and DNA adduct formation in the liver of Zacco platypus following waterborne benzo(a)pyrene exposure: implications for biomarker determination.

    Science.gov (United States)

    Lee, Jin Wuk; Kim, Yong Hwa; Yoon, Seokjoo; Lee, Sung Kyu

    2014-09-01

    Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon that causes mutations and tumor formation. Zacco platypus is a sentinel species that is suitable for monitoring aquatic environments. We studied cytochrome P450 system (CYP system) expression and DNA adduct formation in the liver of Z. platypus following waterborne exposure to BaP. The results showed both dose and time dependency. The significant induction levels of CYP system mRNA and protein reached maximums at 2 days and 14 days, respectively, and hepatosomatic index was maximally induced at 4 days during 14 days BaP exposure. DNA adduct formation was significantly induced compared to corresponding controls (t-test, p adduct formation was a useful biomarker in risk assessment of waterborne BaP exposure at 4 days. CYP1A was a more sensitive biomarker than CYP reductase for BaP exposure when considering both the mRNA and protein level. Furthermore, our results show that Z. platypus is a useful species for assessing the risk of waterborne BaP exposure.

  4. Preparation and Use of Water-borne Aluminium Powder Baking Varnish%水性铝粉烤漆的研制与应用

    Institute of Scientific and Technical Information of China (English)

    商培; 董立志; 刘宝勇; 赵建成

    2012-01-01

    介绍了一种水性铝粉烤漆的研制方法,阐述了润湿分散剂、流平剂、助溶剂、树脂、定向剂等对铝粉定向效果的影响。通过试验筛选出水性铝粉烤漆所需的原材料,制成高性能的涂膜,确定最终配方。试验多次优化配方和生产工艺,为研制高性能的水性铝粉烤漆提供设计思路和理论依据。%This paper introduces a preparation method of water-borne aluminum powder baking varnish and narrates the influence of wetting dispersant, leveling agent, co-solvent, resin, orientation agent on the orientation effect of aluminum powder. Through experiments, the materials for water-borne aluminum powder baking varnish are selected to prepare high performance coatings and the final formula is determined. The optimization of formulation and production technology in this paper provides design idea and theoretical basis for the preparation of water-borne aluminum powder baking varnish.

  5. New Research Progress of Modification of Waterborne Polyurethane%水性聚氨酯的改性研究新进展

    Institute of Scientific and Technical Information of China (English)

    潘季荣; 黄森; 肖新颜

    2012-01-01

    水性聚氨酯(WPU)广泛应用于建筑、涂料、电气绝缘及国防等领域,但是由于WPU制备过程中会引入亲水基团,导致其耐水耐油性、耐化学品性、耐候性等不如人意,需对其进行改性。本文对WPU的最新改性方法,如有机硅改性、有机氟改性、丙烯酸酯改性、环氧树脂改性、纳米无机材料改性等进行了综述,并对WPU改性研究方向进行了展望。%Waterborne polyurethane(WPU) had a widely application in the field such as construction,coatings,electrical insulation and defense.However,the special performance of the waterborne polyurethane can not meet the needs of most user duing to the introduction of hydrophilic groups in the synthesis of the polyurethane.Many attention has been paid to improve the water and oil resistance,chemical resistance,weather resistance of WPU.Several modification methods for waterborne polyurethane,including organosilicone modification,organofluorine modification,acrylate modification,epoxy resin modification and nano-material modification WPU,are summarized.And the future development trend of modified WPU is expected.

  6. Modified waterborne polyurethane and its adhesive properties%改性水性聚氨酯及其粘接性能

    Institute of Scientific and Technical Information of China (English)

    周威; 傅和青

    2013-01-01

    综述了水性聚氨酯的改性方法,包括环氧树脂改性、丙烯酸酯改性、有机硅改性、有机氟改性、纳米材料改性、复合改性。比较了各种改性方法的优缺点,指出了水性聚氨酯胶粘剂所存在的问题,展望了水性聚氨酯胶粘剂改性发展趋势。%The modification methods of waterborne polyurethane was summarized,including the modification with epoxy resins,acrylates,organic silicons,organic fluorine compounds,nanomaterials and the multi-modification.The advantages and disadvantages of these modification methods were compared.The problems of the waterborne polyurethane adhesives were analyzed,and the development trend of the waterborne polyurethane adhesives was put foward.

  7. Study on preparation and properties of water-borne acrylic coatings modified by organic silicone%有机硅氧烷改性水性丙烯酸树脂的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    王晶丽; 来水利; 于金凤; 周凯祥

    2016-01-01

    The water-borne acrylic resin modified by silicone was prepared by solution poly-merization using methyl methyl-methacrylate(MMA) ,butyl-acrylate(BA) ,acrylic-acid(AA) and hydroxyethyl-acrylate(HEA) ,glycidyl Versatate(E-10p)and vinyl triethoxy silane(AC-75) as raw material .The effects of the dosage of initiator ,organic silicon amount and join , neutralization degree on the properties of the resin were investigated .The resin structure , particle size ,particle morphology and thermal stability were characterized and analyzed by FT-IR ,TEM ,nano particle surface potential analyzer and TGA ,in addition to test its per-formance of synthetic resin .Results showed that when the dosage of initiator is 2 .5% ,organ-ic silicon dosage is 6% ,neutralization degree is 100% ,silicone modified water-borne acrylic resin was obtained with solid content 32% ,viscosity 4 .5 Pa・s ,adhesion1 degree ,flexibility 2 mm ,good water resistance and heat resistant .%以甲基丙烯酸甲酯(MMA)、丙烯酸丁酯(BA)、丙烯酸(AA)、丙烯酸羟乙酯(HEA)、叔碳酸缩水甘油脂(E-10p)和乙烯基三乙氧基硅烷(AC-75)为原料,采用溶液聚合法制备出有机硅改性水性丙烯酸树脂,考察了引发剂用量、有机硅加入方式及用量、中和度对树脂性能的影响。通过傅里叶变换红外光谱仪(FT-IR)、透射电镜(TEM )、纳米粒度表面电位分析仪以及热重仪(TGA)分别对聚合物的结构、粒子形貌及粒径、热稳定性等进行了表征和分析,检测了合成树脂的漆膜性能.结果表明:当引发剂BPO为2.5%(单体总质量),有机硅为6%,中和度为100%时,合成了固含量32%、粘度4.5 Pa・s、附着力1级、柔顺性2 m m、耐水性及耐热性好的有机硅改性水性丙烯酸树脂.

  8. Cholera vaccination campaign contributes to improved knowledge regarding cholera and improved practice relevant to waterborne disease in rural Haiti.

    Directory of Open Access Journals (Sweden)

    Omowunmi Aibana

    2013-11-01

    Full Text Available Haiti's cholera epidemic has been devastating partly due to underlying weak infrastructure and limited clean water and sanitation. A comprehensive approach to cholera control is crucial, yet some have argued that oral cholera vaccination (OCV might result in reduced hygiene practice among recipients. We evaluated the impact of an OCV campaign on knowledge and health practice in rural Haiti.We administered baseline surveys on knowledge and practice relevant to cholera and waterborne disease to every 10th household during a census in rural Haiti in February 2012 (N = 811. An OCV campaign occurred from May-June 2012 after which we administered identical surveys to 518 households randomly chosen from the same region in September 2012. We compared responses pre- and post-OCV campaign. Post-vaccination, there was improved knowledge with significant increase in percentage of respondents with ≥ 3 correct responses on cholera transmission mechanisms (odds ratio[OR] 1.91; 95% confidence interval[CI] 1.52-2.40, preventive methods (OR 1.83; 95% CI 1.46-2.30, and water treatment modalities (OR 2.75; 95% CI 2.16-3.50. Relative to pre-vaccination, participants were more likely post-OCV to report always treating water (OR 1.62; 95% CI 1.28-2.05. Respondents were also more likely to report hand washing with soap and water >4 times daily post-vaccine (OR 1.30; 95% CI 1.03-1.64. Knowledge of treating water as a cholera prevention measure was associated with practice of always treating water (OR 1.47; 95% CI 1.14-1.89. Post-vaccination, knowledge was associated with frequent hand washing (OR 2.47; 95% CI 1.35-4.51.An OCV campaign in rural Haiti was associated with significant improvement in cholera knowledge and practices related to waterborne disease. OCV can be part of comprehensive cholera control and reinforce, not detract from, other control efforts in Haiti.

  9. Cholera Vaccination Campaign Contributes to Improved Knowledge Regarding Cholera and Improved Practice Relevant to Waterborne Disease in Rural Haiti

    Science.gov (United States)

    Aibana, Omowunmi; Franke, Molly; Teng, Jessica; Hilaire, Johanne; Raymond, Max; Ivers, Louise C.

    2013-01-01

    Background Haiti's cholera epidemic has been devastating partly due to underlying weak infrastructure and limited clean water and sanitation. A comprehensive approach to cholera control is crucial, yet some have argued that oral cholera vaccination (OCV) might result in reduced hygiene practice among recipients. We evaluated the impact of an OCV campaign on knowledge and health practice in rural Haiti. Methodology/Principal Findings We administered baseline surveys on knowledge and practice relevant to cholera and waterborne disease to every 10th household during a census in rural Haiti in February 2012 (N = 811). An OCV campaign occurred from May–June 2012 after which we administered identical surveys to 518 households randomly chosen from the same region in September 2012. We compared responses pre- and post-OCV campaign. Post-vaccination, there was improved knowledge with significant increase in percentage of respondents with ≥3 correct responses on cholera transmission mechanisms (odds ratio[OR] 1.91; 95% confidence interval[CI] 1.52–2.40), preventive methods (OR 1.83; 95% CI 1.46–2.30), and water treatment modalities (OR 2.75; 95% CI 2.16–3.50). Relative to pre-vaccination, participants were more likely post-OCV to report always treating water (OR 1.62; 95% CI 1.28–2.05). Respondents were also more likely to report hand washing with soap and water >4 times daily post-vaccine (OR 1.30; 95% CI 1.03–1.64). Knowledge of treating water as a cholera prevention measure was associated with practice of always treating water (OR 1.47; 95% CI 1.14–1.89). Post-vaccination, knowledge was associated with frequent hand washing (OR 2.47; 95% CI 1.35–4.51). Conclusion An OCV campaign in rural Haiti was associated with significant improvement in cholera knowledge and practices related to waterborne disease. OCV can be part of comprehensive cholera control and reinforce, not detract from, other control efforts in Haiti. PMID:24278498

  10. Study on Waterborne Polyurethane Antifouling Coatings%水性聚氨酯防污涂料的研究

    Institute of Scientific and Technical Information of China (English)

    李志生; 于雪艳; 陈正涛; 王科; 李旭朝; 肖玲; 桂泰江

    2015-01-01

    采用丙烯酸/苯乙烯共聚物乳液为基体树脂,通过添加聚氨酯分散体提高了涂膜的耐磨性、柔韧性、抗开裂性,筛选不同防污剂和助剂等,制备了养殖渔网防污损的水性防污涂料,对涂层的防污性、附着力等性能进行了评价,并对涂层进行微观表征和毒性测试,制备的水性防污涂料具有6个月的防污期效,满足水产养殖业对渔网防污涂料的要求,同时由于是水性的,对海洋环境无污染,在生产和使用过程中对大气环境和人员身体无影响,符合环保要求。%The waterborne antifouling coatings was prepared for ifshnet anti-fouling by using acrylic/styrene copolymer emulsion as the basic resin, adding polyurethane dispersions to improve wear resistance, lfexibility and crack resistance of the coatings and selecting different anti-fouling agents and additives. The antifouling property, adhesion and other properties were evaluated for the coating iflms and the micro-characterization and toxicity test were carried out as well. The prepared anti-fouling coatings had the effective anti-fouling period of 6 months, which met the requirements of the cultivating ifshery for ifshnet anti-fouling coatings. Meanwhile, as the coatings were waterborne and had no pollution to marine environment, it had no effect on the air environment and human bodies during the processes of its production and application and met the requirement of environmental protection.

  11. Quantification of microbial risks to human health caused by waterborne viruses and bacteria in an urban slum.

    Science.gov (United States)

    Katukiza, A Y; Ronteltap, M; van der Steen, P; Foppen, J W A; Lens, P N L

    2014-02-01

    To determine the magnitude of microbial risks from waterborne viruses and bacteria in Bwaise III in Kampala (Uganda), a typical slum in Sub-Saharan Africa. A quantitative microbial risk assessment (QMRA) was carried out to determine the magnitude of microbial risks from waterborne pathogens through various exposure pathways in Bwaise III in Kampala (Uganda). This was based on the concentration of Escherichia coli O157:H7, Salmonella spp., rotavirus (RV) and human adenoviruses F and G (HAdV) in spring water, tap water, surface water, grey water and contaminated soil samples. The total disease burden was 680 disability-adjusted life years (DALYs) per 1000 persons per year. The highest disease burden contribution was caused by exposure to surface water open drainage channels (39%) followed by exposure to grey water in tertiary drains (24%), storage containers (22%), unprotected springs (8%), contaminated soil (7%) and tap water (0.02%). The highest percentage of the mean estimated infections was caused by E. coli O157:H7 (41%) followed by HAdV (32%), RV (20%) and Salmonella spp. (7%). In addition, the highest infection risk was 1 caused by HAdV in surface water at the slum outlet, while the lowest infection risk was 2.71 × 10(-6) caused by E. coli O157:H7 in tap water. The results show that the slum environment is polluted, and the disease burden from each of the exposure routes in Bwaise III slum, with the exception of tap water, was much higher than the WHO reference level of tolerable risk of 1 × 10(-6) DALYs per person per year. The findings of this study provide guidance to governments, local authorities and nongovernment organizations in making decisions on measures to reduce infection risk and the disease burden by 10(2) to 10(5) depending on the source of exposure to achieve the desired health impacts. The infection risk may be reduced by sustainable management of human excreta and grey water, coupled with risk communication during hygiene awareness

  12. One-pot synthesis and control of aqueous soluble and organic soluble carbon dots from a designable waterborne polyurethane emulsion

    Science.gov (United States)

    Gu, Jiangjiang; Hu, Donghua; Huang, Jin; Huang, Xin; Zhang, Qiuhong; Jia, Xudong; Xi, Kai

    2016-02-01

    Carbon dots (CDs) have a wide range of applications and have drawn great interest in the recent decade. The fabrication and control of CDs with different solubilities are still urgent problems for their practical use. In this paper, aqueous soluble and organic soluble CDs (ACDs, OCDs) were produced by one-pot hydrothermal treatment of a designable waterborne polyurethane (WPU) emulsion. The difference in the solubility and fluorescence of these two kinds of CDs was attributed to the various functional groups on the surface, which were derived from the different segment fragments formed by hydrothermal treatment of a block polymer. It was found that the yields of the ACDs and OCDs could be regulated by means of selecting different soft segments in WPU. The more hydrophobic soft segments could result in an increase of the OCDs and a decrease of the ACDs. While the soft segments were hydrophilic or hydrolysable under hydrothermal conditions, only ACDs were obtained. The ACDs had good fluorescence and showed low cytotoxicity for use in multicolour bio-imaging. The OCDs processed good solubility in a wide range of organic solvents and were suitable for preparing fluorescent composite films with polymers.Carbon dots (CDs) have a wide range of applications and have drawn great interest in the recent decade. The fabrication and control of CDs with different solubilities are still urgent problems for their practical use. In this paper, aqueous soluble and organic soluble CDs (ACDs, OCDs) were produced by one-pot hydrothermal treatment of a designable waterborne polyurethane (WPU) emulsion. The difference in the solubility and fluorescence of these two kinds of CDs was attributed to the various functional groups on the surface, which were derived from the different segment fragments formed by hydrothermal treatment of a block polymer. It was found that the yields of the ACDs and OCDs could be regulated by means of selecting different soft segments in WPU. The more

  13. Examining waterborne and dietborne routes of exposure and their contribution to biological response patterns in fathead minnow (Pimephales promelas)

    Energy Technology Data Exchange (ETDEWEB)

    Rozon-Ramilo, Lisa D., E-mail: lisa.ramilo@usask.ca [University of Saskatchewan, Toxicology Centre, 44 Campus Drive, Saskatoon, Saskatchewan S7N 5B3 (Canada); Dube, Monique G., E-mail: moniqe.dube@usask.ca [University of Saskatchewan, School of Environment and Sustainability, 117 Science Place, Saskatoon, Saskatchewan S7N 2X8 (Canada); Squires, Allison J., E-mail: allison.squires@usask.ca [University of Saskatchewan, Toxicology Centre, 44 Campus Drive, Saskatoon, Saskatchewan S7N 5B3 (Canada); Niyogi, Som, E-mail: som.niyogi@usask.ca [University of Saskatchewan, Department of Biology, 112 Science Place, Saskatoon, Saskatchewan S7N 5E2 (Canada)

    2011-10-15

    Highlights: Objective (i) was achieved by isolating each route of exposure (diet, water and the combination of the two) and comparing it to a control. The metal mining effluent studied encompassed several different effluent types including: mine water, mill facility, tailing impoundment, treatment pond, treatment facility, seepage and surface drainage effluent. Experiment 1 examined exposure pathways by isolating effluent exposure through the diet, water or the combination of the two. Experiment 2 examined whether differences in Fathead minnow responses occurred when fish were fed a live or frozen (dead) diet of chironomids. Multiple trophic levels (consumers and carnivores) were placed in each artificial stream simultaneously. Primary route of exposure to Fathead minnow when held in control water and fed effluent-exposed chironomid larvae. - Abstract: The objectives of the current study were: (i) to gain a better understanding of the relative importance of water and diet as routes of exposure causing toxicity in fathead minnow (FHM) exposed to metal mining effluents (MME) using a full factorial water/food experimental design (Experiment 1), and (ii) to assess differences in the effects of food quality on toxicity by comparing FHM fed both a live and frozen diet of Chironomus dilutus (Experiment 2). The results showed significant increases in general water quality parameters (e.g., hardness, conductivity) and various metals in the effluent treatment waters compared to control waters, with maximum increase seen in the multi-trophic streams. Metals accumulation (Rb, Al, Se, Sr, Tl, Ce, Co, Cu, Pb) effects of both waterborne and multi-trophic exposures were significant in one or more fathead minnow tissue type (muscle, gonads, liver, larvae) relative to those in the control systems. Condition factor and liver somatic index (LSI) of FHM were also significantly affected in both exposures by one or both routes of exposure (water and/or diet). In addition, cumulative

  14. Particle Mechanics

    CERN Document Server

    Collinson, Chris

    1995-01-01

    * Assumes no prior knowledge* Adopts a modelling approach* Numerous tutorial problems, worked examples and exercises included* Elementary topics augmented by planetary motion and rotating framesThis text provides an invaluable introduction to mechanicsm confining attention to the motion of a particle. It begins with a full discussion of the foundations of the subject within the context of mathematical modelling before covering more advanced topics including the theory of planetary orbits and the use of rotating frames of reference. Truly introductory , the style adoped is perfect for those u

  15. Particle Physics

    Science.gov (United States)

    Cooper, Necia Grant; West, Geoffrey B.

    1988-06-01

    Preface; Introduction; Part I. Theoretical Framework: 1. Scale and dimension - From animals to quarks Geoffrey B. West; 2. Particle physics and the standard model Stuart Raby, Richard C. Slansky and Geoffrey B. West; QCD on a Cray: the masses of elementary particles Gerald Guralnik, Tony Warnock and Charles Zemach; Lecture Notes - From simple field theories to the standard model; 3. Toward a unified theory: an essay on the role of supergravity in the search for unification Richard C. Slansky; 4. Supersymmetry at 100 GeV Stuart Raby; 5. The family problem T. Goldman and Michael Martin Nieto; Part II. Experimental Developments: 6. Experiments to test unification schemes Gary H. Sanders; 7. The march toward higher energies S. Peter Rosen; LAMPF II and the High-Intensity Frontier Henry A. Thiessen; The SSC - An engineering challenge Mahlon T. Wilson; 8. Science underground - the search for rare events L. M. Simmons, Jr; Part III. Personal Perspectives: 9. Quarks and quirks among friends Peter A. Carruthers, Stuart Raby, Richard C. Slansky, Geoffrey B. West and George Zweig; Index.

  16. 改性水性醇酸树脂的合成及其应用%Study on synthesis of modified waterborne alkyd resin and its application

    Institute of Scientific and Technical Information of China (English)

    张诚; 吕翠玉; 顾卓伟; 苏畅; 徐立新

    2011-01-01

    以脂肪油、间苯二甲酸、偏苯三酸酐及三羟甲基丙烷为主要原料,采用熔融成盐法合成了水性醇酸树脂,其中苯甲酸为改性剂.研究了改性水性醇酸树脂及其氨基烤漆的配方及其制备工艺,并用红外光谱对树脂的结构进行了分析.通过理论计算结合实验确定改性水性醇酸树脂最终酸值为50~55,油度为35.讨论了油度、最终酸值、苯甲酸和偏苯三酸酐的加入量、脂肪油、多元醇对水性醇酸树脂及漆膜性能的影响,优选了助溶剂和中和剂,其中苯甲酸的质量分数为6%左右,偏苯三酸酐的质量分数为10%左右的树脂综合性能较好,且具有良好的水溶性和稳定性.用HMMM作交联树脂,可制得性能优异的水性醇酸氨基烤漆.性能测试表明:所制烤漆硬度可高达3H,光泽为95,附着力等其他技术指标均达到或超过溶剂型涂料的技术指标,可以直接用于铁制品上.%The waterborne alkyd resin was prepared through melting esterifaction and salified method, based on fatty oil, isophthalic acid ( IPA ), trimellitic anhydride ( TMA ), trimethylolpropane, and modified with benzoic acid(BA). The formulation and production technology of the modified waterborne alkyd resin and its alkyd-amino paint were investigated. The structure of waterborne alkyd resin was characterized by infrared spectroscopy. The final acid value of the modified waterborne alkyd resin was determined by theoretical studies in combination with some experiments. The final acid value of the modified waterborne alkyd resin was 50~55, it's oil degrees was 35. The influences of the oil degree, the final acid value, BA concentration, TMA content, fatty oil and polyol type on the properties of alkyd resin and coating film were discussed. Some experiments for the optimization of cosolvent and neutralizer were performed. The results showed that resin with good performance could be obtained when BA concentration was 6% and TMA

  17. Mitochondrial energetic metabolism perturbations in skeletal muscles and brain of zebrafish (Danio rerio) exposed to low concentrations of waterborne uranium

    Energy Technology Data Exchange (ETDEWEB)

    Lerebours, Adelaide; Adam-Guillermin, Christelle [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Bat 186, BP 3, 13115 Saint-Paul-Lez-Durance Cedex (France); Brethes, Daniel [CNRS, UMR 5095, Institut de Biochimie et Genetique Cellulaires, Universite Victor Segalen-Bordeaux 2 (France); Frelon, Sandrine; Floriani, Magali; Camilleri, Virginie; Garnier-Laplace, Jacqueline [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire, Bat 186, BP 3, 13115 Saint-Paul-Lez-Durance Cedex (France); Bourdineaud, Jean-Paul, E-mail: jp.bourdineaud@epoc.u-bordeaux1.fr [CNRS, UMR 5095, Institut de Biochimie et Genetique Cellulaires, Universite Victor Segalen-Bordeaux 2 (France)

    2010-10-01

    Anthropogenic release of uranium (U), originating from the nuclear fuel cycle or military activities, may considerably increase U concentrations in terrestrial and aquatic ecosystems above the naturally occurring background levels found throughout the environment. With a projected increase in the world-wide use of nuclear power, it is important to improve our understanding of the possible effects of this metal on the aquatic fauna at concentrations commensurate with the provisional drinking water guideline value of the World Health Organization (15 {mu}g U/L). The present study has examined the mitochondrial function in brain and skeletal muscles of the zebrafish, Danio rerio, exposed to 30 and 100 {mu}g/L of waterborne U for 10 and 28 days. At the lower concentration, the basal mitochondrial respiration rate was increased in brain at day 10 and in muscles at day 28. This is due to an increase of the inner mitochondrial membrane permeability, resulting in a decrease of the respiratory control ratio. In addition, levels of cytochrome c oxidase subunit IV (COX-IV) increased in brain at day 10, and those of COX-I increased in muscles at day 28. Histological analyses performed by transmission electron microscopy revealed an alteration of myofibrils and a dilatation of endomysium in muscle cells. These effects were largest at the lowest concentration, following 28 days of exposure.

  18. Nitrification characteristics of nitrobacteria immobilized in waterborne polyurethane in wastewater of corn-based ethanol fuel production

    Institute of Scientific and Technical Information of China (English)

    Yamei Dong; Zhenjia Zhang; Yongwei Jin; Jian Lu; Xuehang Cheng; Jun Li; Yan-yan Deng; Ya-nan Feng; Dongning Chen

    2012-01-01

    A technology to achieve stable and high ammonia nitrogen removal rates for corn distillery wastewater (ethanol fuel production) treatment has been designed.The characteristics of nitrifying bacteria entrapped in a waterborne polyurethane (WPU) gel carrier were evaluated after acclimation.In the acclimation period,nitrification rates of WPU-immobilized nitrobacteria were monitored and polymerase chain reaction (PCR) was also carried out to investigate the change in ammonium-oxidizing bacteria.The results showed that the pellet nitrification rates increased from 21 to 228 mg-N/(L-pellet-hr) and the quantity of the ammonia oxidation bacteria increased substantially during the acclimation.A continuous ammonia removal experiment with the anaerobic pond effluent of a distillery wastewater system was conducted with immobilized nitrifying bacteria for 30 days using an 80 L airlift reactor with pellets at a fill ratio of 15% (V/V).Under the conditions of 75 mg/L influent ammonia,hydraulic retention time (HRT) of 3.7-5,6 hr,and dissolved oxygen (DO) of 4 mg/L,the effluent ammonia concentration was lower than 10 mg/L and the ammonia removal efficiency was 90%.While the highest ammonia removal rate,162 mg-N/(L-pellet-hr),was observed when the HRT was 1.3 hr.

  19. Preparation and antibacterial property of waterborne polyurethane/Zn-Al layered double hydroxides/ZnO nanocomposites.

    Science.gov (United States)

    Zhang, Wei-De; Zheng, Yun-Min; Xu, Yang-Sen; Yu, Yu-Xiang; Shi, Qing-Shan; Liu, Lihong; Peng, Hong; Ouyang, Yousheng

    2013-01-01

    In this work, a novel environmental-friendly waterborne polyurethane/ZnAl-layered double hydroxides/ZnO nanoparticles composite (WPU/ZnAl-LDHs/ZnO) was synthesized via in-situ polymerization. ZnAl-LDHs and ZnAl-LDHs/ZnO were synthesized by refluxing in an oil bath. In order to disperse ZnAl-LDHs/ZnO homogeneously into WPU matrix, ZnAl-LDHs/ZnO was firstly functionalized by isophorone diisocyanate. The incorporated content of ZnAl-LDHs/ZnO in the composite has profound effect on such physical properties as mechanical strength, thermal stability and water swelling. It is demonstrated that appropriate amount of ZnAl-LDHs/ZnO with good dispersion in the WPU matrix significantly improves the physical performance of the composites. Finally, the antibacterial activity of the composite was tested against G(-) Escherichia coli and G(+) Staphylococcus aureus. The results indicate that WPU incorporated with ZnAl-LDHs/ZnO shows strong antibacterial activity upon contact.

  20. Water-borne diseases and extreme weather events in Cambodia: review of impacts and implications of climate change.

    Science.gov (United States)

    Davies, Grace I; McIver, Lachlan; Kim, Yoonhee; Hashizume, Masahiro; Iddings, Steven; Chan, Vibol

    2014-12-23

    Cambodia is prone to extreme weather events, especially floods, droughts and typhoons. Climate change is predicted to increase the frequency and intensity of such events. The Cambodian population is highly vulnerable to the impacts of these events due to poverty; malnutrition; agricultural dependence; settlements in flood-prone areas, and public health, governance and technological limitations. Yet little is known about the health impacts of extreme weather events in Cambodia. Given the extremely low adaptive capacity of the population, this is a crucial knowledge gap. A literature review of the health impacts of floods, droughts and typhoons in Cambodia was conducted, with regional and global information reviewed where Cambodia-specific literature was lacking. Water-borne diseases are of particular concern in Cambodia, in the face of extreme weather events and climate change, due to, inter alia, a high pre-existing burden of diseases such as diarrhoeal illness and a lack of improved sanitation infrastructure in rural areas. A time-series analysis under quasi-Poisson distribution was used to evaluate the association between floods and diarrhoeal disease incidence in Cambodian children between 2001 and 2012 in 16 Cambodian provinces. Floods were significantly associated with increased diarrhoeal disease in two provinces, while the analysis conducted suggested a possible protective effect from toilets and piped water. Addressing the specific, local pre-existing vulnerabilities is vital to promoting population health resilience and strengthening adaptive capacity to extreme weather events and climate change in Cambodia.

  1. Water-Borne Diseases and Extreme Weather Events in Cambodia: Review of Impacts and Implications of Climate Change

    Directory of Open Access Journals (Sweden)

    Grace I. Davies

    2014-12-01

    Full Text Available Cambodia is prone to extreme weather events, especially floods, droughts and typhoons. Climate change is predicted to increase the frequency and intensity of such events. The Cambodian population is highly vulnerable to the impacts of these events due to poverty; malnutrition; agricultural dependence; settlements in flood-prone areas, and public health, governance and technological limitations. Yet little is known about the health impacts of extreme weather events in Cambodia. Given the extremely low adaptive capacity of the population, this is a crucial knowledge gap. A literature review of the health impacts of floods, droughts and typhoons in Cambodia was conducted, with regional and global information reviewed where Cambodia-specific literature was lacking. Water-borne diseases are of particular concern in Cambodia, in the face of extreme weather events and climate change, due to, inter alia, a high pre-existing burden of diseases such as diarrhoeal illness and a lack of improved sanitation infrastructure in rural areas. A time-series analysis under quasi-Poisson distribution was used to evaluate the association between floods and diarrhoeal disease incidence in Cambodian children between 2001 and 2012 in 16 Cambodian provinces. Floods were significantly associated with increased diarrhoeal disease in two provinces, while the analysis conducted suggested a possible protective effect from toilets and piped water. Addressing the specific, local pre-existing vulnerabilities is vital to promoting population health resilience and strengthening adaptive capacity to extreme weather events and climate change in Cambodia.

  2. 水体中隐孢子虫的检测方法%Detection methods for waterborne Cryptosporidium spp

    Institute of Scientific and Technical Information of China (English)

    段莉平; 冯耀宇; 曹建平

    2008-01-01

    隐孢子虫(Cryptosporidium spp.)是一类顶复门肠道原虫,隐孢子虫病(cryptosporidiosis)是由隐孢子虫引起的人兽共患原虫病.由于隐孢子虫病可通过水传播,故该文对水体中隐孢子虫的常规检测包括样品收集、浓缩、卵囊分离和染色镜检等步骤,和常用分子生物学方法如多种PCR方法和基于核酸序列的扩增方法等进行综述.%Cryptosporidium spp.ale Apicomplexan protozoan parasites that are pathogen of zoonotic eryptosporidiosis.Cryptosporidiosis can be transmitted via water.This review summarized the routine detection including sample collection,concentration,oocyst purification and microscopic observation,and molecular de-tection such as various PCR methods and nucleic acid sequence-based amplification for detection of waterborne Cryptosporidium.

  3. Micelle-template synthesis of hollow silica spheres for improving water vapor permeability of waterborne polyurethane membrane

    Science.gov (United States)

    Bao, Yan; Wang, Tong; Kang, Qiaoling; Shi, Chunhua; Ma, Jianzhong

    2017-04-01

    Hollow silica spheres (HSS) with special interior spaces, high specific surface area and excellent adsorption and permeability performance were synthesized via micelle-template method using cetyl trimethyl ammonium bromide (CTAB) micelles as soft template and tetraethoxysilane (TEOS) as silica precursor. SEM, TEM, FT-IR, XRD, DLS and BET-BJH were carried out to characterize the morphology and structure of as-obtained samples. The results demonstrated that the samples were amorphous with a hollow structure and huge specific surface area. The growth of HSS was an inward-growth mechanism along template. Notably, we have provided a new and interesting fundamental principle for HSS materials by precisely controlling the ethanol-to-water volume ratio. In addition, the as-obtained HSS were mixed with waterborne polyurethane (WPU) to prepare WPU/HSS composite membrane. Various characterizations (SEM, TEM, FT-IR and TGA) revealed the morphology, polydispersity and adherence between HSS and WPU. Performance tests showed that the introduction of HSS can improve the water vapor permeability of composite membrane, promoting its water resistance and mechanical performance at the same time.

  4. Nitrification characteristics of nitrobacteria immobilized in waterborne polyurethane in wastewater of corn-based ethanol fuel production.

    Science.gov (United States)

    Dong, Yamei; Zhang, Zhenjia; Jin, Yongwei; Lu, Jian; Cheng, Xuehang; Li, Jun; Deng, Yan-Yan; Feng, Ya-Nan; Chen, Dongning

    2012-01-01

    A technology to achieve stable and high ammonia nitrogen removal rates for corn distillery wastewater (ethanol fuel production) treatment has been designed. The characteristics of nitrifying bacteria entrapped in a waterborne polyurethane (WPU) gel carrier were evaluated after acclimation. In the acclimation period, nitrification rates of WPU-immobilized nitrobacteria were monitored and polymerase chain reaction (PCR) was also carried out to investigate the change in ammonium-oxidizing bacteria. The results showed that the pellet nitrification rates increased from 21 to 228 mg-N/(L-pellet x hr) and the quantity of the ammonia oxidation bacteria increased substantially during the acclimation. A continuous ammonia removal experiment with the anaerobic pond effluent of a distillery wastewater system was conducted with immobilized nitrifying bacteria for 30 days using an 80 L airlift reactor with pellets at a fill ratio of 15% (V/V). Under the conditions of 75 mg/L influent ammonia, hydraulic retention time (HRT) of 3.7-5.6 hr, and dissolved oxygen (DO) of 4 mg/L, the effluent ammonia concentration was lower than 10 mg/L and the ammonia removal efficiency was 90%. While the highest ammonia removal rate, 162 mg-N/(L-pellet x hr), was observed when the HRT was 1.3 hr.

  5. Novel microbiological and spatial statistical methods to improve strength of epidemiological evidence in a community-wide waterborne outbreak.

    Directory of Open Access Journals (Sweden)

    Katri Jalava

    Full Text Available Failures in the drinking water distribution system cause gastrointestinal outbreaks with multiple pathogens. A water distribution pipe breakage caused a community-wide waterborne outbreak in Vuorela, Finland, July 2012. We investigated this outbreak with advanced epidemiological and microbiological methods. A total of 473/2931 inhabitants (16% responded to a web-based questionnaire. Water and patient samples were subjected to analysis of multiple microbial targets, molecular typing and microbial community analysis. Spatial analysis on the water distribution network was done and we applied a spatial logistic regression model. The course of the illness was mild. Drinking untreated tap water from the defined outbreak area was significantly associated with illness (RR 5.6, 95% CI 1.9-16.4 increasing in a dose response manner. The closer a person lived to the water distribution breakage point, the higher the risk of becoming ill. Sapovirus, enterovirus, single Campylobacter jejuni and EHEC O157:H7 findings as well as virulence genes for EPEC, EAEC and EHEC pathogroups were detected by molecular or culture methods from the faecal samples of the patients. EPEC, EAEC and EHEC virulence genes and faecal indicator bacteria were also detected in water samples. Microbial community sequencing of contaminated tap water revealed abundance of Arcobacter species. The polyphasic approach improved the understanding of the source of the infections, and aided to define the extent and magnitude of this outbreak.

  6. Preparation and properties of high storage stability polyester polyol dispersion for two-component waterborne polyurethane coating

    Science.gov (United States)

    Hao, H.; Hu, J. Q.; Wang, F.; Tu, W. P.

    2017-01-01

    A new type of polyester polyol dispersion with good storage stability was prepared based on a hydrophilic monomer 5-sodium sulfodimethyl isophthalate (5-SIPM), and frequently-used monomers such as neopentyl glycol (NPG), dimethyl terephthalate (DMT), dimethyl phthalate (DMP) and trimethylolpropane (TMP) by the transpolycondensation and polycondensation method. The polyester polyol dispersion was characterized by FTIR and GPC. The proper content of these monomers were determined by the performance of polyester dispersion: the content of TMP was 15wt%, the content of NPG was 7.5wt% and the hydrophilic monomer 5-SIPM content was 5wt%. Two-component waterborne polyurethane (2K-WPU) coatings were prepared by Bayhydur® XP2487/1 and polyester polyol dispersions, which were stored before and after at 40 ° for 6 weeks, the prepared films have no differences in drying time, adhesion, pencil hardness, gloss and chemical resistance, the result also reveals that the polyester polyol dispersion have excellent storage stability resistance.

  7. 环保节能型水性聚氨酯建筑涂料研究进展%Progress of environmentally friendly and energy-saving waterborne polyurethane architectural coatings

    Institute of Scientific and Technical Information of China (English)

    张凡; 杨建军; 吴庆云; 张建安; 吴明元

    2014-01-01

    Using water as the dispersion medium, the waterborne polyurethane coating is environmentally friendly compared to the solvent-based polyurethane coating in terms of reducing VOC emissions greatly. This article has reviewed research progress in waterborne polyurethane coating to achieve the energy-saving and environment-friendly buildings over the last decade. There are four aspects as the focus of this review:the thermal insulation coating based on waterborne polyurethane, the phase change thermal storage materials with polyurethane shell, the UV curable waterborne polyurethane coating and the improvment of water resistence and bacterium resistance of waterborne polyurethane coating.%综述了近几年来环保型、节能型水性聚氨酯涂料的研发和应用情况。主要包括:水性聚氨酯(WPU)保温隔热涂料,以聚氨酯为壳层材料的相变储能材料,UV固化WPU工艺,提高水性聚氨酯涂料的耐水性和防霉抗菌性等。

  8. 电子束固化水性聚氨酯丙烯酸酯的制备及性能%Synthesis and properties of electron beam curing waterborne polyurethane acrylate

    Institute of Scientific and Technical Information of China (English)

    徐海涛; 朱令干; 廖建华; 梁红波; 熊磊

    2012-01-01

    研究了一种制备水性聚氨酯丙烯酸酯的新方法,通过在扩链剂分子结构中组装离子基团来改善亲水性,解决了聚氨酯丙烯酸酯与水难相溶的问题.采用这种方法制备了一种聚氨酯丙烯酸酯产物,使用FTIR和1H NMR对产物结构进行了表征.对产物与水的储存稳定性、黏度、电子束固化行为及固化后性能进行了研究.结果表明,分散乳液储存稳定性好,经电子束固化后性能(如硬度、附着力、光泽度、柔韧性、热稳定性)优良.%A new preparation method of waterborne polyurethane acrylate was developed. With this method the hydrophilicity of polyurethane acrylate was improved by assembling ionic groups on the molecular structure of chain extender, and the immiscibility of polyurethane acrylate with water was resolved. The polyurethane acrylate prepared by this method was characterized by Fourior-transformed infrared spectroscopy (FTIR) and ]H nuclear magnetic resonance (:H NMR). Its stability with water, viscosity, electron beam curing behavior and cured properties were studied. The results showed that the as-prepared product had water storage stability and the emulsion particle sizes decreased with increasing water content in the range from 0. 50 to 0. 75. The product properties cured by electron beam, such as thermal stability, hardness, adhesion, gloss, flexibility were excellent.

  9. 合成革用非离子水性聚氨酯的合成与改性研究%Synthesis and Modified of Non-ionic Waterborne Polyurethane for Synthetic Leather

    Institute of Scientific and Technical Information of China (English)

    郭勇生; 马兴元; 吴泽; 张淑芳; 杨西萍

    2013-01-01

    以丙烯酸丁酯为稀释剂,甲苯二异氰酸酯(TDI)、聚丙二醇(PPG)、聚乙二醇(PEG)为基本原料,乙二醇(EG)为扩链剂,甲基丙烯酸羟乙酯(HEA)为封端剂,合成了丙烯酸酯改性非离子水性聚氨酯粘合剂乳液.结果显示:当预聚温度和时间分别为70℃和2h,扩链的温度和时间分别为70℃和3h,PEG用量为30%时,改性的乳液具有优良的性能.此外,改性产品的粘合强度略微下降,耐水性增强,平均粒径增大,热稳定性显著提高.%In this paper, a non-ionic waterborne polyurethane adhesive was synthesized, which used butyl acrylic (BA) as diluents monomer, toluene diisocyanate (TDI), propylene glycol(PPG), polyether glycol(PEG) as basic raw materials, ethylene glycol (EG) as chain extension, hydroxyethyl methacrylate ( HE A) as the end capping agent. The experiment results show that when the temperature and time of prepolymerization is 70℃ and 2 hours, the temperature and time of chain extension is 70℃ and 3 hours, the amount of PEG content is 30% , the modified emulsion has excellent performance. In addition, the bond strength of modified product slightly decreases, the water resistance increases, the average particle size becomes larger and the thermal stability is obviously improved.

  10. 咪唑封闭水性聚氨酯复鞣剂的制备及表征%Preparation and characterization of imidazole blocked waterborne polyurethane retanning agent

    Institute of Scientific and Technical Information of China (English)

    李刚辉; 李新; 银召霞; 沈一丁; 李培枝; 赖小娟

    2011-01-01

    Imidazole-blocked waterborne polyurethane retanning agent(BPU) was prepared by the reaction of 1,6-hexanediamine(HDI),dimethylol propionic acid(DMPA),2,2-bis(4-hydroxyphenyl)propane(BPA),polyesterglycol and imidazole as blocking agent through molecular design method.FT-IR,dynamic laser light scattering(DLS),TEM,TGA,DSC characterized the structure of BPU,the particle size distribution and morphology of the resultant dispersions and thermal properties of BPU,respectively.At the same time,molecular basis of action mechanism of BPU were analyzed.The results show that structures of carboxyl,imidazole ring and polyurethane are found in BPU molecular structure.The morphology of the particle is comparatively regular sphericity with core/shell structure and the poly-dispersity of particle sizes is the microcosmic reason of BPU with favorable selective filling.Indicated by TGA,the heat-resistant properties of BPU is properly high and decrease appreciably with increase of the blocked ratio of BPU.According to the result of DSC analysis,deblocking temperature of BPU ranges from 107.5 to 124.5℃ and its peak value is 115.1 ℃.During the application,the deblocking of BPU rarely occurs and it is advantageous for the increasing of auxiliary dyeing.%通过分子设计,以咪唑为封闭剂,1,6-己二异氰酸酯(HDI)、二羟甲基丙酸(DMPA)、2,2-二(4-羟基苯基)丙烷、聚酯二醇为原料制备出咪唑封闭水性聚氨酯复鞣剂(BPU)。用FT-IR、动态激光光散射(DLS)、TEM、TGA、DSC分别对BPU分子结构、乳胶粒形态及热性能进行了表征,分析了BPU复鞣剂的分子作用基础。结果表明产物分子结构中出现了羧基、咪唑环和聚氨酯结构;乳胶粒呈较为规则的、具有核壳结构的球形,粒径的多分散性是BPU具有良好选择填充性的微观原因。TGA和DSC分析显示BPU耐热性较高并

  11. Synthesis and Properties of Cationic Waterborne Polyurethane Dispersions Modified by Castor Oil%蓖麻油改性阳离子型水性聚氨酯的合成及性能

    Institute of Scientific and Technical Information of China (English)

    饶舟; 张威; 王焕; 许戈文; 黄毅萍

    2012-01-01

    采用蓖麻油、异佛尔酮二异氰酸酯、聚己二酸乙二醇酯、聚丙二醇、一缩二乙二醇、N-甲基二乙醇胺、三羟甲基丙烷,合成了一系列蓖麻油改性阳离子型水性聚氨酯分散液.用红外光谱分析、粒径测试、智能电子拉力试验、摆杆硬度测试、热分析等对所合成的聚氨酯的结构、乳液的粒径和膜性能进行测试.结果表明:随着蓖麻油用量的增加,阳离子型水性聚氨酯乳液的粒径逐渐增加,膜的摆杆硬度及耐水性能逐渐增强:蓖麻油在树脂中质量分数达8.4%时,膜的摆杆硬度达到0.86;而蓖麻油在树脂中质量分数达6.4%时,阳离子型水性聚氨酯胶膜浸泡24 h的吸水率几近为零;且蓖麻油的引入,使胶膜的耐热性也有所提高.%Castor oil modified cationic waterborne polyurethane ( WPU) dispersions are prepared from castor oil,isophorone diisocyanate ( IPDI) ,polyethyleneglycol adipate ( PEGA ) ,polypropylene glycol (PPG),diethylene glycol (DEG) ,N - methyldiethanolamine ( MDEA) and trimethylolpropane(TMP) . The structure,emulsion particle distribution and film properties of the resulted WPU are characterized by Fourier transform infrared( FT - IR) ,particle size analyzer,intelligent tensile machine,pendulum tester and thermal gravimetric analysis ( TGA ) . The result indicates that the increase of castor oil leads to increase of emulsion particle size,and improvement of pendulum hardness and water resistance of the cured film. Specifically when the content of castor oil is 8. 4% ,the pendulum hardness of film is 0. 86. And when the content of castor oil is wt. 6. 4% ,the film shows its water absorption nearly zero after immersed for 24 hrs. Additionally ,the incorporation of castor oil causes improvement of heat resistance.

  12. 辐射法制备内交联聚醚型水性聚氨酯的研究∗%Study on the Internal Crosslinked Waterborne Polyether-Polyurethane Prepared by γ-Radiation

    Institute of Scientific and Technical Information of China (English)

    酒永斌; 翟宇; 曹巍; 翟彤; 曾心苗; 王连才

    2015-01-01

    以异佛尔酮二异氰酸酯、聚氧化丙烯二醇、二羟甲基丙酸、季戊四醇三丙烯酸酯( PETA)和甲基丙烯酸羟乙酯( HEMA)为原料,并以γ射线辐射处理,制备了内交联型水性聚氨酯( WPU)乳液。分析测试了机械稳定性、粘度、粒径及力学性能等,研究了两种封端剂含量、辐照剂量对WP U乳液性能的影响;同时研究了其胶膜的力学性能、吸水率等变化情况。结果表明,所制备的交联型WPU乳液具有较好的稳定性,平均粒径小于0�3μm,WPU经过辐照后,其粒径变化不大。与不含PETA及HEMA的样品比较,引入PETA及HEMA并辐射交联后,WPU胶膜的拉伸强度明显增加,而断裂伸长率和吸水率降低。%Crosslinked waterborne polyurethane( WPU) dispersions were prepared by isophorone diisocyanate, polypropylene glycol, dimethylolproprionic acid, pentaerythritol triacrylate ( PETA ) , hydroxyethyl methacrylate ( HEMA) and were treated byγ⁃ray radiation. Stability, viscosity and particle size of the dispersions were studied. The effects of radiation dose and blocking agents contents on the properties of the dispersions, mechanical properties and water absorption of the casting film were also investigated. The results showed that the crosslinked latex had good stability and small particle size with average particle size of 0�3 μm. Compared with the WPU without PETA and HEMA, tensile strength of the internal crosslinked WPU film was increased, the elongation and the water ab⁃sorption were decreased.

  13. Particle kickers

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    These devices are designed to provide a current pulse of 5000 Amps which will in turn generate a fast magnetic pulse that steers the incoming beam into the LHC. Today, the comprehensive upgrade of the LHC injection kicker system is entering its final stages. The upgraded system will ensure the LHC can be refilled without needing to wait for the kicker magnets to cool, thus enhancing the performance of the whole accelerator.   An upgraded kicker magnet in its vacuum tank, with an upgraded beam screen. The LHC is equipped with two kicker systems installed at the injection points (near points 2 and 8, see schematic diagram) where the particle beams coming from the SPS are injected into the accelerator’s orbit. Each system comprises four magnets and four pulse generators in which the field rises to 0.12 Tesla in less than 900 nanoseconds and for a duration of approximately 8 microseconds. Although the injection kickers only pulse 12 times to fill the LHC up with beam, the LHC beam circ...

  14. Leaching of nanoparticles from experimental water-borne paints under laboratory test conditions

    Science.gov (United States)

    Zuin, Stefano; Gaiani, Marco; Ferrari, Arlen; Golanski, Luana

    2014-01-01

    In this study we investigated the release of titanium dioxide (TiO2), silver (Ag) and silica (SiO2) engineered nanoparticles (ENPs) from three different paints by using standardized water immersion test for coatings. Fibre-cement panels were coated with paints containing ENPs and then exposed to UV light and abraded to simulate weathering. After the static water immersion test, we observed a very low release of Ti (4-8 μg/l), while the Ag measured in leachates was under detection limit (0.1 μg/l). A small release of Si was measured in leachates, with 73 mg/l of Si released from paints containing SiO2 ENPs after 120 h of water immersion. The cumulative loss of Si was about 1.8 % with respect to initial amount of Si in paint. Microscopic results highlighted that SiO2 ENPs are mainly released in form of agglomerates with other particles, and only very few single SiO2 ENPs were found in leachates. The results confirmed that Si migration is related to immersion cycles (wetting and drying cycles) of tested paints.

  15. Preparation and Characterization of Waterborne Polyurethaneurea Composed of Dimer Fatty Acid Polyester Polyol

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available A series of polyurethaneurea (PUU aqueous dispersions, which were stable at ambient temperature for more than 1 year, were prepared with C 36 -dimer-fatty-acid-based polyester polyol, isophorone diisocyanate, dimethylol propionic acid, and ethylenediamine. The particle size of all these PUU (DPU aqueous dispersions ( <100 nm was less than that of comparable specimens, that is, poly-(neopentyl glycol adipate polyester-polyol-based PUU (APU aqueous dispersions, and the polydispersity index was very narrow ( ≤1.13 . The films prepared with the DPU aqueous dispersions exhibited excellent waterproof performance, such as low amount of water absorption (1.3 wt%, and good mechanical properties (hardness and tensile strength, resulting from the strong hydrogen bonding in urea carbonyl groups and the perfect ordered structure of hard segments compared with those prepared with the APU aqueous dispersions. The surface hydrophobicity of the films prepared with modified DPU aqueous dispersions, which were modified with a fluorinated polyacrylate emulsion, was excellent, as the water contact angle on the surface of such films rose up to 100. The mechanical properties of such modified DPU films were further enhanced.

  16. Cellular, particle and environmental parameters influencing attachment in surface waters: a review.

    Science.gov (United States)

    Liao, C; Liang, X; Soupir, M L; Jarboe, L R

    2015-08-01

    Effective modelling of the fate and transport of water-borne pathogens is needed to support federally required pollution-reduction plans, for water quality improvement planning, and to protect public health. Lack of understanding of microbial-particle interactions in water bodies has sometimes led to the assumption that bacteria move in surface waters not associated with suspended mineral and organic particles, despite a growing body of evidence suggesting otherwise. Limited information exists regarding the factors driving interactions between micro-organisms and particles in surface waters. This review discusses cellular, particle and environmental factors potentially influencing interactions and in-stream transport. Bacterial attachment in the aquatic environment can be influenced by properties of the cell such as genetic predisposition and physiological state, surface structures such as flagella and fimbriae, the hydrophobicity and electrostatic charge of the cell surface, and the presence of outer-membrane proteins and extracellular polymeric substances. The mechanisms and degree of attachment are also affected by characteristics of mineral and organic particles including the size, surface area, charge and hydrophobicity. Environmental conditions such as the solution chemistry and temperature are also known to play an important role. Just as the size and surface of chemical particles can be highly variable, bacterial attachment mechanisms are also diverse.

  17. Retention and Migration of Fine Organic Particles within an Agricultural Stream: Toenepi, Waikato, New Zealand

    Science.gov (United States)

    Drummond, J. D.; Davies-Colley, R.; Stott, R.; Sukias, J.; Nagels, J.; Sharp, A.; Packman, A. I.

    2013-12-01

    Fine organic particle dynamics are important to stream biogeochemistry, ecology, and transport of contaminant microbes. These particles migrate downstream through a series of deposition and resuspension events, which results in a wide range of residence times. This retention influences biogeochemical processing and in-stream stores of contaminant microbes that may mobilize during flood events and present a hazard to downstream uses such as water supplies and recreation. We are conducting studies to gain insights into organic particle dynamics in streams, with a campaign of experiments and modeling. The results should improve understanding of nutrient (C, N, P) spiraling and fine sediment movement in streams, and have particular application to microbial hazards. We directly measure microbial transport by including the indicator organism, E. coli, as a tracer, which is compared to a fluorescent inert particle tracer and conservative solute to gain insight on both microbial ecology and waterborne disease transmission. We developed a stochastic model to describe the transport and retention of fine suspended particles in rivers, including advective delivery of particles to the streambed, transport through porewaters, and reversible filtration within the streambed. Because fine particles are only episodically transported in streams, with intervening periods at rest in the bed, this transport process violates conventional advection-dispersion assumptions. Instead we adopt a stochastic mobile-immobile model formulation to describe fine particle transport. We apply this model to measurements of particle transport from multiple tracer experiments in an agricultural stream in the Waikato dairy region of New Zealand, and use the model to improve interpretation of baseflow particle dynamics. Our results show the importance of the benthic and hyporheic regions and in-stream vegetation as a reservoir for fine organic particles in streams.

  18. Influencing Factor and Research Progress in Waterborne Polyurethane Adhesive Properties%水性聚氨酯粘接性能的影响因素及研究进展

    Institute of Scientific and Technical Information of China (English)

    郑主宜; 吴晓青; 田龙; 郑静; 李梦华

    2013-01-01

    The waterborne polyurethane (WPU) adhesive several structural factors,mainly including molecular polarity,relative molecular weight, cross-linking, molecular degree of crystalline, which had large effects on adhesive properties of waterborne polyurethane and research progress were discussed. The effective measures to improve the WPU adhesive property were put forward. In the end, the development prospects of waterborne polyurethane adhesive were expected.%综述了水性聚氨酯(WPU)胶粘剂分子极性、相对分子质量、交联、分子结晶度等分子结构因素对粘接性能的影响及进展,提出了改善WPU粘接性能的几个有效措施,并展望了WPU胶粘剂的发展前景.

  19. 浅析水性聚氨酯与溶剂型聚氨酯合成革加工工艺区别%Discussion on Difference of Waterborne and Solvent based Polyurethane in Leather Industry

    Institute of Scientific and Technical Information of China (English)

    郑兆祥; 吕海宁; 范新妹; 洪军燕

    2011-01-01

    The difference of structure and condition between waterborne polyurethane and solvent - based polyurethane was discussed, which leads to the changes of processing in leather industry.The basis and mechanism of waterborne and solvent -based polyurethane in choosing wet processing and release paper were pointed out, which provide effective theoretical support for the development of waterborne polyurethane.%分析了水性聚氨酯与溶剂型聚氨酯在分子结构上的不同及其存在状态的差异,而导致其在合成革加工工艺上有所区别,指出了水性与溶剂型聚氨酯在湿法加工和离型纸方面选择的依据与作用机理,为以后水性聚氨酯的发展提供有力的理论支撑.

  20. 水性聚氨酯的性能研究及其发展前景展望%Research on the performances and outlook on the development prospect of waterborne polyurethane

    Institute of Scientific and Technical Information of China (English)

    李佩佩; 赵振河

    2014-01-01

    水性聚氨酯具有无毒、不易燃烧,对环境几乎没有污染等优点,在织物整理、皮革加工、粘合剂等领域得到了广泛应用。水性聚氨酯取代溶剂型聚氨酯已成为一个重要的发展方向。综述了水性聚氨酯的性能、制备方法及其发展前景。%The waterborne polyurethane was of non-toxic, non-flammability and little pollution to the environment, which was widely applied to textile finishing, leather process and adhesive fields. The waterborne polyurethane has become an important development tendency. The performances and preparation method of the waterborne polyurethane, as well as its development prospect, were reviewed in this paper.

  1. 助剂对水性双组分聚氨酯施工时黏度的影响%Influence of Additives on the Viscosity in Painting Process of Waterborne Two-package Polyurethane

    Institute of Scientific and Technical Information of China (English)

    朱德勇; 朱申敏; 张之涵; 沈剑平

    2012-01-01

    This paper introduces the basic chemical reactions of waterborne two-package polyurethane coatings, focusing on the influence of additives, pigments and fillers on the viscosity of waterborne two-package polyurethane. It also analyzes the reason, providing reference for the design of waterborne two-package polyurethane formulations.%介绍了水性双组分聚氨酯涂料基本化学反应,重点讨论配方中常用的助剂、颜填料对水性双组分聚氨酯混合后黏度的影响及原因分析,对设计水性双组分聚氨酯配方具有参考意义。

  2. Progress on the research of modification of UV-curable waterborne polyurethane-acrylate coating%UV固化水性聚氨酯丙烯酸酯涂料改性的研究进展

    Institute of Scientific and Technical Information of China (English)

    徐吉成; 邱凤仙; 蒋艳; 庄甜; 徐滨滨

    2014-01-01

    Ultraviolet (UV)curable waterborne polyurethane-acrylate is a kind of functional environmental protec-tion coatings.The UV curing technology and waterborne polyurethane-acrylate coatings are introduced.The modifi-cation of UV-curable waterborne polyurethane-acrylate coating is reviewed,and its application prospect and devel-opment trend are prospected.%概述紫外光的固化原理与水性聚氨酯丙烯酸酯涂料的性能,综述UV固化水性聚氨酯丙烯酸酯涂料氟、有机硅、环氧树脂及超支化等改性的最新研究进展,展望应用前景与发展趋势。

  3. Using a biological aerated filter to treat mixed water-borne volatile organic compounds and assessing its emissions

    Institute of Scientific and Technical Information of China (English)

    CHENG Wen-Hsi

    2009-01-01

    A biological aerated filter (BAF) was evaluated as a fixed-biofilm processes to remove water-borne volatile organic compounds (VOCs) from a multiple layer ceramic capacitor (MLCC) manufacturing plant in southern Taiwan.The components of VOC were identified to be toluene,1,2,4-trimethylbenzene,1,3,5-trimethylbenzene,bromodichloromethane and isopropanol (IPA).The full-scale BAF was constructed of two separate reactors in series,respectively using 10-cm and 15-cm diameter polypropylene balls as the packing materials and a successful preliminary bench-scale experiment was performed to feasibility.Performance results show that the BAF removed over 90% chemical oxygen demand (COD) from the influent with (1188 ± 605) mg/L of COD.A total organic loading of 2.76 kg biochemical oxygen demand (BOD)/(m~3 packing·d) was determined for the packed bed,in which the flow pattern approached that of a mixed flow.A limited VOC concentration of (0.97 ± 0.29) ppmv (as methane) was emitted from the BAF system.Moreover,the emission rate of VOC was calculated using the proposed formula,based on an air-water mass equilibrium relationship,and compared to the simulated results obtained using the Water 9 model.Both estimation approaches of calculation and model simulation using Water 9 evaluating VOC emissions reveal that 0.1% IPA (0.0031-0.0037 kg/d) was aerated into a gaseous phase,and 30% to 40% (0.006-0.008 kg/d) of the toluene was aerated.

  4. Early genotoxic response and accumulation induced by waterborne copper, lead, and arsenic in European seabass, Dicentrarchus labrax.

    Science.gov (United States)

    Canalejo, Antonio; Diaz-de-Alba, Margarita; Granado-Castro, M Dolores; Cordoba, Francisco; Espada-Bellido, Estrella; Galindo-Riaño, M Dolores; Torronteras, Rafael

    2016-02-01

    Cu, Pb, and As, which are among the most abundant metals in the aquatic environment, are also among the most health-threatened by causing diverse cellular injuries. The aim of this study was to assess and compare the potential early induction of genotoxic effects after waterborne Cu, Pb, and As exposure in European seabass, Dicentrarchus labrax, a commercial widely cultured fish, using the micronucleus (MN) assay in peripheral blood erythrocytes. Fish were exposed under laboratory conditions to nominal solutions ranging 0-10 mg/L for 24 and 96 h. Furthermore, actual metal ion concentrations were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) or differential pulse anodic stripping voltammetry (DPASV) in water and four fish tissues differentially related to environmental exposition and metal accumulation, i.e. the gills, liver, muscle, and brain. Dose-dependent increases of micronuclei (MNi) frequency were observed after these very short exposures; based on measured metal concentrations in water, the genotoxic effect ordered as Cu > As > Pb. Significant genotoxic effect at 0.009 mg/L Cu, 0.57 mg/L Pb, and 0.01 mg/L As was seen. For Cu and Pb these are only slightly higher, but for As it is notably lower than the USEPA criteria of maximum concentration to prevent acute toxicity in aquatic organisms. Furthermore, genotoxicity was differentially related to metal accumulation. MNi frequency correlated positively with the content of Pb in all the organs, with the content of As in liver and gills and only with the content of Cu in the brain. In conclusion, our findings raised environmental concerns because these depicted a genotoxic potential of Cu, Pb, and As after a very short exposure to low but environmentally relevant concentrations, too close to regulatory thresholds. In addition, the MN test in D. labrax could be considered an early biomarker of genotoxicity induced by these metals in fish.

  5. Comparison of waterborne and intraperitoneal exposure to fipronil in the Caspian white fish (Rutilus frisii) on acute toxicity and histopathology.

    Science.gov (United States)

    Ardeshir, Rashid Alijani; Zolgharnein, Hossein; Movahedinia, Abdolali; Salamat, Negin; Zabihi, Ebrahim

    2017-01-01

    Fipronil is an effective insecticide widely used in agriculture with potential ecotoxicological consequences. The median lethal dose (LD50) and concentration (LC50) of fipronil in 16.3 g Caspian white fish, Rutilus frisii kutum fingerlings were determined. To determine the LD50, a total of 133 fish were assigned to 19 tanks (7 fish/tank) including one control and 6 treatment groups (300, 450, 550, 650, 750, 850 mg/kg). Fish were injected intraperitoneally and monitored at 96 h. The LD50 of fipronil was 632 mg/kg suggesting it was slightly toxic to the Caspian white fish. To determine LC50, 114 fish were assigned to 19 tanks (6 fish/tank) including one control and 6 treatment groups (300, 400, 500, 600, 700, 800 μg/L). The LC50 of fipronil was 572 μg/L, which was highly toxic to the fish. The degree of tissue change (DTC) in vital organs from moribund fish exposed via waterborne exposure showed severe damage (DTC: 71 ± 52 for 700 μg/L) in the gill, including aneurisms, extensive fusion and necrosis. The fish exposed through the intraperitoneal route seemed to have severe lesions (DTC: 66 ± 50 for 750 mg/kg) in the kidney, involving hemorrhage, tubular degeneration and necrosis. The liver had no significant differences in DTC values between the two routes and showed pyknosis and sinusoid dilation. Hematoxylin and eosin staining did not show any histological alterations in the brain but nissl staining showed some alterations in distribution of purkinje cells. Generally, this study showed that the route of exposure to fipronil not only affects its acute toxicity but also determines the main target organs of toxicity and histopathological alterations in Caspian white fish.

  6. Potential sources of bias in the use of Escherichia coli to measure waterborne diarrhoea risk in low-income settings.

    Science.gov (United States)

    Ercumen, Ayse; Arnold, Benjamin F; Naser, Abu Mohd; Unicomb, Leanne; Colford, John M; Luby, Stephen P

    2017-01-01

    Escherichia coli is the standard water quality indicator for diarrhoea risk. Yet, the association between E. coli and diarrhoea is inconsistent across studies without a systematic assessment of methodological differences behind this variation. Most studies measure water quality cross-sectionally with diarrhoea, risking exposure misclassification and reverse causation. Studies use different recall windows for self-reported diarrhoea; longer periods increase potential outcome misclassification through misrecall. Control of confounding is inconsistent across studies. Additionally, diarrhoea measured in unblinded intervention trials can present courtesy bias. We utilised measurements from a randomised trial of water interventions in Bangladesh to assess how these factors affect the E. coli-diarrhoea association. We compared cross-sectional versus prospective measurements of water quality and diarrhoea, 2-versus 7-day symptom recall periods, estimates with and without controlling for confounding and using measurements from control versus intervention arms of the trial. In the control arm, 2-day diarrhoea prevalence, measured prospectively 1 month after water quality, significantly increased with log10 E. coli (PR = 1.50, 1.02-2.20). This association weakened when we used 7-day recall (PR = 1.18, 0.88-1.57), cross-sectional measurements of E. coli and diarrhoea (PR = 1.11, 0.79-1.56) or did not control for confounding (PR = 1.20, 0.88-1.62). Including data from intervention arms led to less interpretable associations, potentially due to courtesy bias, effect modification and/or reverse causation. By systematically addressing potential sources of bias, our analysis demonstrates a clear relationship between E. coli in drinking water and diarrhoea, suggesting that the continued use of E. coli as an indicator of waterborne diarrhoea risk is justified. © 2016 John Wiley & Sons Ltd.

  7. The physiological consequences of exposure to chronic, sublethal waterborne nickel in rainbow trout (Oncorhynchus mykiss): exercise vs resting physiology.

    Science.gov (United States)

    Pane, Eric F; Haque, Aziz; Goss, Greg G; Wood, Chris M

    2004-03-01

    In rainbow trout (Oncorhynchus mykiss), following chronic (42 day) exposure to both 384 microg Ni l(-1) and 2034 microg Ni l(-1), Ni accumulation was greatest in the gill, kidney and plasma, with the plasma as the main sink for Ni. Indeed, trapped plasma analysis revealed that extensive loading of Ni in the plasma accounted for substantial percentages of accumulated Ni in several tissues including the liver and heart. Accumulated Ni in the gill and kidney was less dependent on plasma Ni concentration, suggesting a more intracellular accumulation of Ni in these tissues. We present evidence for a clear, persistent cost of acclimation to chronic, sublethal Ni exposure. Chronic (40-99 day) exposure to sublethal waterborne Ni (243-394 microg Ni l(-1); approximately 1% of the 96 h LC(50)) impaired the exercise physiology, but not the resting physiology, of rainbow trout. Ni acted as a limiting stressor, decreasing maximal rates of oxygen consumption (MO2,max) during strenuous exercise in trout exposed for 34 days to sublethal Ni. This drop in high-performance gas exchange was attributed mainly to a reduction in relative branchial diffusing capacity (D(rel)) caused by thickening of secondary lamellae. Morphometric analysis of the gills of chronically exposed fish revealed overall swelling of secondary lamellae, as well as hypertrophic respiratory epithelia within secondary lamellae. Additionally, contraction of the lamellar blood pillar system and narrowing of interlamellar water channels occurred, possibly contributing to decreased high-performance gas exchange. Decreased aerobic capacity persisted in fish previously exposed to nickel despite a clean-water exposure period of 38 days and an almost complete depuration of gill Ni, suggesting that extrabranchial mechanisms of chronic Ni toxicity may also be important. Chronic impairment of such a dynamically active and critical organ as the gill may depress the overall fitness of a fish by impairing predator avoidance, prey

  8. Progress of Waterborne Giardiasis Study%水源性贾弟虫病(giardiasis)研究进展

    Institute of Scientific and Technical Information of China (English)

    王中卫

    2011-01-01

    贾弟虫(Giardia)是一种世界性分布的体内寄生原生动物,可感染家畜、野生动物和人类。该虫可通过饮用水源等水体传播,其所导致的贾弟虫病(giardiasis)是最频发的水源性疾病之一,典型症状是腹泻、腹痛、反胃、呕吐、胃胀和发烧。本文综述了贾弟虫的分类、流行病学和检测方法等,目的是提出疾病预警系统,建立快速响应机制,以防止饮用水中贾弟虫病爆发。%Giardia is a cosmopolitan enteric protozoan with a very wide host range, including domestic and wild animal species as well as human beings. The parasite transmitted by the water route including drinking water sources and has become the most frequently identified cause of waterborne disease. The most prominent symptoms of giardiasis are diarrhoea, abdominal pain, nausea, vomiting, flatulence and fever. Taxonomy, epidemiology, detection methods of Giardia are presented in this paper. The objectives are to provide early warning system to permit the possibility for fast response in a risky situation in order to prevent outbreaks of giardiasis through human drinking water.

  9. Most probable number - loop mediated isothermal amplification (MPN-LAMP) for quantifying waterborne pathogens in <25min.

    Science.gov (United States)

    Ahmad, Farhan; Stedtfeld, Robert D; Waseem, Hassan; Williams, Maggie R; Cupples, Alison M; Tiedje, James M; Hashsham, Syed A

    2017-01-01

    We are reporting a most probable number approach integrated to loop mediated isothermal technique (MPN-LAMP) focusing on Gram-negative Escherichia coli and Gram-positive Enterococcus faecalis bacterial cells without nucleic acids extraction. LAMP assays for uidA from E. coli and gelE from E. faecalis were successfully performed directly on cells up to single digit concentration using a commercial real time PCR instrument. Threshold time values of LAMP assays of bacterial cells, heat treated bacterial cells (95°C for 5min), and their purified genomic DNA templates were similar, implying that amplification could be achieved directly from bacterial cells at 63°C. Viability of bacterial cells was confirmed by using propidium monoazide in a LAMP assay with E. faecalis. To check its functionality on a microfluidic platform, MPN-LAMP assays targeting <10CFU of bacteria were also translated onto polymeric microchips and monitored by a low-cost fluorescence imaging system. The overall system provided signal-to-noise (SNR) ratios up to 800, analytical sensitivity of <10CFU, and time to positivity of about 20min. MPN-LAMP assays were performed for cell concentrations in the range of 10(5)CFU to <10CFU. MPN values from LAMP assays confirmed that the amplifications were from <10CFU. The method described here, applicable directly on cells at 63°C, eliminates the requirement of complex nucleic acids extraction steps, facilitating the development of sensitive, rapid, low-cost, and field-deployable systems. This rapid MPN-LAMP approach has the potential to replace conventional MPN method for waterborne pathogens.

  10. 水性环氧树脂涂料研究与应用进展%Research Progress and Application on Waterborne Epoxy Resin Coating

    Institute of Scientific and Technical Information of China (English)

    牛凯辉; 宋伟强; 谢宝粘; 吴龙超

    2015-01-01

    The methods for preparation of waterborne epoxy resin were systematically introduced, including mechanism methods, phase inversion technique, curing agent emulsification method and chemistry modification technique, and all of them were discussed. With epoxy groups, hydroxyl group and other active groups on the molecular chain, epoxy resin could be composited with other resins to improve the comprehensive performance of waterborne epoxy resin coatings. The commonly used methods of modification had polyurethane modification, polyacrylate modification, phosphate modification, silicone modification and nanoparticles modification. The main application fields of waterborne epoxy resin coating were also given. Finally, the development prospects were predicted.%系统地介绍了环氧树脂水性化技术,包括机械法、相反转法、固化剂乳化法及化学改性法,并对各方法进行了评论。环氧树脂分子链上带有环氧基、羟基等活泼基团,可以与其它树脂复合使用,提高水性环氧树脂涂料的综合性能,常用方法有聚氨酯改性、聚丙烯酸酯改性、磷酸酯改性、有机硅改性以及纳米粒子改性。介绍了水性环氧树脂涂料的主要应用领域,并对其发展前景进行了展望。

  11. [Factors associated with the quality of well water and the prevalence of waterborne diseases in the municipality of Abomey-Calavi in Benin].

    Science.gov (United States)

    Degbey, Cyriaque; Makoutode, Michel; Agueh, Victoire; Dramaix, Michele; de Brouwer, Christophe

    2011-01-01

    The objective of this work is to assess the factors associated with the water quality of household wells, suggest solutions to improve it, and study the prevalence of water-borne diseases in this community. The quality of well water and the prevalence of waterborne diseases in the municipality were studied by analysis of the microbiological indicators currently used to assess drinking-water quality and the retrospective study of waterborne diseases treated in the local health centres. The wells surveyed were contaminated by Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, Salmonella spp, Clostridium perfringens and fecal streptococci, at prevalences of 12.5, 12.2, 12.2, 12.1, 12 and 11.1%, respectively. The high rates of diarrhea, urinary infections, typhoid fever and abdominal pain found in the retrospective study were consistent with the results of the well-water quality assessment. These results showed that human activity has strongly influenced water quality, especially the lack of sanitation in the different districts and neighbourhoods. Other factors affecting the vulnerability of well water include poor waste management by households, the low depth of the water table, the nature of the soil, and the permeability of the aquifer used. Improvement in water quality, sanitation, and personal hygiene will make it possible to reduce considerably the propagation of these diseases and several others. It is therefore important to provide these populations with the necessary equipment for an adequate drinking water supply, but also to promote health education to avoid water pollution. The search for solutions to these problems will lead to a plan for future action.

  12. A Systematic Review of Waterborne Disease Outbreaks Associated with Small Non-Community Drinking Water Systems in Canada and the United States.

    Directory of Open Access Journals (Sweden)

    Wendy Pons

    Full Text Available Reports of outbreaks in Canada and the United States (U.S. indicate that approximately 50% of all waterborne diseases occur in small non-community drinking water systems (SDWSs. Summarizing these investigations to identify the factors and conditions contributing to outbreaks is needed in order to help prevent future outbreaks.The objectives of this study were to: 1 identify published reports of waterborne disease outbreaks involving SDWSs in Canada and the U.S. since 1970; 2 summarize reported factors contributing to outbreaks, including water system characteristics and events surrounding the outbreaks; and 3 identify terminology used to describe SDWSs in outbreak reports.Three electronic databases and grey literature sources were searched for outbreak reports involving SDWSs throughout Canada and the U.S. from 1970 to 2014. Two reviewers independently screened and extracted data related to water system characteristics and outbreak events. The data were analyzed descriptively with 'outbreak' as the unit of analysis.From a total of 1,995 citations, we identified 50 relevant articles reporting 293 unique outbreaks. Failure of an existing water treatment system (22.7% and lack of water treatment (20.2% were the leading causes of waterborne outbreaks in SDWSs. A seasonal trend was observed with 51% of outbreaks occurring in summer months (p<0.001. There was large variation in terminology used to describe SDWSs, and a large number of variables were not reported, including water source and whether water treatment was used (missing in 31% and 66% of reports, respectively.More consistent reporting and descriptions of SDWSs in future outbreak reports are needed to understand the epidemiology of these outbreaks and to inform the development of targeted interventions for SDWSs. Additional monitoring of water systems that are used on a seasonal or infrequent basis would be worthwhile to inform future protection efforts.

  13. 水性聚氨酯膨胀型阻燃涂料的研究进展%The Research Status and Latest Progress of Waterborne Polyurethane Intumescent Flame Retardant Coatings

    Institute of Scientific and Technical Information of China (English)

    梅锦岗; 杨建军; 吴明元; 吴庆云; 张建安

    2012-01-01

    水性聚氨酯涂料若未经阻燃处理,存在引发火灾的隐患,因此水性聚氨酯的阻燃研究是水性聚氨酯功能化的重要方向之一。介绍了水性聚氨酯阻燃涂料的分类,按不同分类标准可分为共混复配型和反应型,膨胀型和非膨胀型。对水性聚氨酯阻燃涂料阻燃效应和阻燃机理进行了探讨,并重点介绍水性聚氨酯膨胀型阻燃涂料的研究现状。最后提出了现在水性聚氨酯膨胀型阻燃涂料存在的问题,并对水性聚氨酯膨胀型阻燃涂料的发展趋势进行了展望。%Waterborne polyurethane coatings without the flame retardant treatment are flammable, so the research about the flame retardant waterborne polyurethane is an important research direction. The classification of waterborne polyurethane flame retardant coatings was introduced. Flame retardant coatings can be categorized as blending and reactive compound, intumescent and non-intumescent according to different classification criteria. Flame retardant effect and flame retardant mechanisms of waterborne polyurethane flame retardant coatings were discussed and the research of intumescent flame retardant polyurethane coatings was highlighted. Finally, the problems which waterborne intumescent flame retardant polyurethane coating existed and the trends of waterborne intumeseent flame retardant polyurethane coatings development are were proposed.

  14. Dysfunctions at human intestinal barrier by water-borne protozoan parasites: lessons from cultured human fully differentiated colon cancer cell lines.

    Science.gov (United States)

    Liévin-Le Moal, Vanessa

    2013-06-01

    Some water-borne protozoan parasites induce diseases through their membrane-associated functional structures and virulence factors that hijack the host cellular molecules and signalling pathways leading to structural and functional lesions in the intestinal barrier. In this Microreview we analyse the insights on the mechanisms of pathogenesis of Entamoeba intestinalis, Giardia and Cryptosporidium observed in the human colon carcinoma fully differentiated colon cancer cell lines, cell subpopulations and clones expressing the structural and functional characteristics of highly specialized fully differentiated epithelial cells lining the intestinal epithelium and mimicking structurally and functionally an intestinal barrier. © 2013 John Wiley & Sons Ltd.

  15. The Application Study of Waterborne Polyurethane Metallic Paint in Large Vehicles%水性聚氨酯金属闪光漆在大型交通工具中的应用研究

    Institute of Scientific and Technical Information of China (English)

    邱学科; 朱德勇

    2014-01-01

    简述了大型交通工具用水性化涂料体系特征。阐明了水性聚氨酯金属闪光漆的配制方法、性能和原材料的选择,并介绍了水性聚氨酯金属闪光漆的施工工艺。%The characteristics of waterborne coatings system for large vehicles were briefly introduced;the preparing methods,performance and materials selection of waterborne polyurethane metallic paint were explained;and the application technology of the paint was introduced.

  16. The Latest Research Progress of Waterborne Polyurethane Technology at Home and Abroad%水性聚氨酯技术的国内外最新研究进展

    Institute of Scientific and Technical Information of China (English)

    高明; 罗刚; 刘治海

    2012-01-01

    The research progress of modification technology of waterborne polyurethane was reviewed and the research status of the application of these new technologies for synthesis was elaborated,as well as the synthesis of waterborne polyurethane was proposed.%综述了水性聚氨酯改性技术的研究进展,阐述了国内外将这些新技术应用于合成中的研究现状,并对水性聚氨酯的合成提出展望。

  17. Preparation of Waterborne Two-Component Polyurethane Coatings for the Aircraft Cabin Interior Decoration%飞机舱内装饰用水性双组分聚氨酯涂料的制备

    Institute of Scientific and Technical Information of China (English)

    董晓蓉

    2015-01-01

    A waterborne two-component polyurethane coatings for the aircraft cabin interior decoration was prepared. The influences of waterborne resin,curing agent,flame retardant,antiscratch agent on the adhesion, flame resistance,stain resistance,scratch resistance of the coatings were discussed.%制备了一种飞机舱内装饰用水性双组分聚氨酯涂料.讨论了水性树脂、固化剂、阻燃剂、抗划伤剂对其附着力、阻燃性、耐沾污性、抗划痕性等性能的影响.

  18. Study of particle swarm optimization particle trajectories

    CSIR Research Space (South Africa)

    Van den Bergh, F

    2006-01-01

    Full Text Available provides a formal proof that each particle converges to a stable point. An empirical analysis of multidimensional stochastic particles is also presented. Experimental results are provided to support the conclusions drawn from the theoretical findings...

  19. 氟改性双组分水性丙烯酸聚氨酯涂料性能研究%Research of Fluorine-Modified Two Component Waterborne Acrylic Polyurethane Coating Performance

    Institute of Scientific and Technical Information of China (English)

    许海燕; 张兴元; 戴家兵; 许飞; 李治; 周静

    2012-01-01

    A series of waterborne hydroxyl polyacrylate resin with different fluorine content were successfully prepared by solution polymerization, using dodecafluoroheptyl methacrylate (DFMA) , acrylate acid (AA) , hydroxyethyl methacrylate (HEMA) , methyl methacrylate (MMA) and butyl acrylate (BA) as monomers. Furthermore , the hydroxyl acrylic resins were cured with hydrophilically modified polyisocyanate curing agent (Bay-hydur XP 2655) to obtain two-component waterborne acrylic polyurethane (2K-WPU) coatings. FT-IR was employed to investigate the structure of the resin and cured films. The contact angle, water swelling ratio and varnish properties of the cured films were tested, respectively. The test result showed that the resins had an average particle size ranging from 28. 2 nm to 68. 1 ran and exhibited unimodal size distributions. The experiment revealed that the contact angle of 2K-WPU films increased from 70. 3° to 97. 6° and the water swelling ratio decreased from 11. 4% to 6. 31% with the DFMA content in hydroxyl polyacrylate resin increasing from 0 to 20% , indicating that the water resistance of 2K-WPU was greatly improved by the incorporation of fluorine-containing component. In addition, varnish test showed that the fluorine-modified 2K-WPU exhibited excellent properties.%以甲基丙烯酸十二氟庚酯(DFMA)、丙烯酸(AA)、甲基丙烯酸羟乙酯(HEMA)、甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为原料,采用溶液聚合法合成了一系列氟含量不同的水性羟基丙烯酸树脂.将含氟水性羟基丙烯酸树脂、亲水性异氰酸酯固化剂和助剂混合制备氟改性双组分水性丙烯酸聚氨酯(2K-WPU)涂料.利用傅里叶变换红外光谱(FT-IR)对其结构进行了表征,并对涂料的接触角、吸水率和清漆性能分别进行了测试.结果表明,该水性树脂粒径在28.2~68.1 nm之间,粒径分布均匀.当水性羟基丙烯酸树脂组成中DFMA质量分数从0增加至20%时,所制备氟改性2K

  20. Synthesis and Application of Double Modified Waterborne Polyurethane Dispersion%双重改性水性聚氨酯分散体的合成及应用

    Institute of Scientific and Technical Information of China (English)

    郭玉; 朱强; 刘志刚; 刘顺; 陆嘉星

    2014-01-01

    The double modified waterborne polyurethane dispersion was prepared by isocyanate, polycaprolac-tone diols, epoxy resin E-51 and castor oil. The results showed that the waterborne polyurethane film pencil hard-ness was H and water resistance was 72 h without exception when NCO/OH molar ratio, the content of DMPA and the neutralization degree of triethylamine was 1�3, 4% ~6% and 80%, respectively.%以异氰酸酯、聚己内酯二元醇、环氧树脂E-51、二羟甲基丙酸和蓖麻油为主要原料制备了环氧树脂和蓖麻油双重改性的水性聚氨酯分散体。结果表明,当NCO与OH摩尔比为1�3、DMPA添加质量分数为4%~6%、三乙胺中和度为80%时,所得涂膜铅笔硬度H,耐水性72 h无异常,满足了水性木器面漆的性能要求。

  1. Biodegradation of a biochar-modified waterborne polyacrylate membrane coating for controlled-release fertilizer and its effects on soil bacterial community profiles.

    Science.gov (United States)

    Zhou, Zijun; Du, Changwen; Li, Ting; Shen, Yazhen; Zeng, Yin; Du, Jie; Zhou, Jianmin

    2015-06-01

    Biochar-modified polyacrylate-like polymers are promising waterborne polymer-based membrane coatings for controlled-release fertilizers. However, the effect of these membrane polymers on paddy soil is unknown. A soil incubation experiment was conducted using Fourier transform infrared photoacoustic spectroscopy to monitor the changes in the polymer-coated membranes in paddy soil, and Biolog EcoPlates and polymerase chain reaction-denaturing gradient gel electrophoresis were used to detect the effects of the membranes on soil bacterial community profiles. Compared to unmodified membranes, the biodegradation rate of the biochar-modified membrane was slower, and the membrane was more intact, which improved and guaranteed the controlled release of nutrients. Compared to the soil without membranes, the biochar-modified membranes, as well as unmodified ones, showed no significant impacts on the composition diversity of soil dominant bacterial community. The activity and functional diversity of soil culturable microbial community during the early stage of incubation were reduced by biochar-modified membranes due to the release of small amount of soluble organic materials but were both recovered in the 12(th) month of the incubation period. Therefore, the biochar-modified waterborne polyacrylate was environmentally friendly, demonstrating its potential both in the development of coated controlled-release fertilizers and in the utilization of crop residue.

  2. A Multiplex PCR/LDR Assay for Simultaneous Detection and Identification of the NIAID Category B Bacterial Food and Water-borne Pathogens

    Science.gov (United States)

    Rundell, Mark S.; Pingle, Maneesh; Das, Sanchita; Hussain, Aashiq; Ocheretina, Oksana; Charles, Macarthur; Larone, Davise H.; Spitzer, Eric D.; Golightly, Linnie; Barany, Francis

    2014-01-01

    Enteric pathogens that cause gastroenteritis remain a major global health concern. The goal of this study was to develop a multiplex PCR/LDR assay for the detection of all NIAID category B bacterial food and water-borne pathogens directly from stool specimens. To validate the PCR/LDR assay, clinical isolates of Campylobacter spp., Vibrio spp., Shigella spp., Salmonella spp., Listeria monocytogenes, Yersinia enterocolitica, and diarrheagenic Escherichia coli were tested. The sensitivity and specificity of the assay was assessed using a large number of seeded culture-negative stool specimens and a smaller set of clinical specimens from Haiti. The overall sensitivity ranged from 91 to 100% (median 100%) depending on the species. For the majority of organisms the sensitivity was 100%. The overall specificity based on initial testing ranged from 98% to 100% depending on the species. After additional testing of discordant samples the lowest specificity was 99.4%. PCR/LDR detected additional category B agents (particularly diarrheagenic E. coli) in 11/40 specimens from Haiti that were culture-positive for V. cholerae and in approximately 1% of routine culture-negative stool specimens from a hospital in New York. This study demonstrated the ability of the PCR/LDR assay to detect a large comprehensive panel of category B enteric bacterial pathogens as well as mixed infections. This type of assay has the potential to provide earlier warnings of possible public health threats and more accurate surveillance of food and water-borne pathogens. PMID:24709368

  3. Research Progress of Waterborne Epoxy Resin Anticorrosion Coatings%水性环氧防腐涂料的研究进展

    Institute of Scientific and Technical Information of China (English)

    胡永玲

    2013-01-01

    The paper briefly introduced the preparation method of waterborne epoxy resin, from mechanical processres, reversal of phase, Chemical modification method. Their merits and faults, developing trends and synthetise is reviewed. I type and II type Waterborne epoxy resin curing agent is introduced with their Merits and faults, developing trends and preparation method. The development and future application. is forecasted.%  从机械法、相反转法、化学改性法三方面介绍了水性环氧树脂的制备方法,指出了水性环氧树脂的制备方法、优缺点和研究进展。介绍了 I 型水性环氧固化剂和Ⅱ型水性环氧固化剂的制备方法,优缺点和发展趋势。并对水性环氧防腐涂料的发展趋势和应用前景进行了展望。

  4. [Simultaneous determination of 23 ester compounds in cigarette water-borne adhesives by liquid-liquid extraction and gas chromatography-mass spectrometry].

    Science.gov (United States)

    Gong, Shuguo; Kong, Bo; Tuo, Suxing; Dai, Yunhui; Wu, Mingjian; Tan, Liquan; Liu, Wei

    2013-10-01

    A method of gas chromatography-mass spectrometry (GC-MS) with liquid-liquid extraction has been developed for the simultaneous determination of 23 ester compounds including acetate esters, acrylic esters, metacrylic acid esters and phthalate acid esters in cigarette water-borne adhesives. After dispersed in water, the sample was extracted by n-hexane solution containing phenyl ethyl propionate as internal standard substance. Then, the solution was centrifuged and filtrated through a 0.45 microm organic membrane filter. Finally, the solution was separated on a DB-WAXETR column (60 m x 0.25 mm x 0.25 microm), and detected with MS in selected ion monitoring mode, and quantified by internal standard method. The results showed a good linear correlation in the range of 0.4-50.0 mg/L. The recoveries of the ester compounds spiked in the sample were 81.8%-109.1%, and the relative standard deviations (RSDs, n = 5) were less than 4%. The limits of detection (LODs) and limits of quantification (LOQs were in the ranges of 0.02-0.76 mg/kg and 0.04-2.52 mg/kg, respectively. The method is simple, time-saving, and has high sensitivity and good reproducibility. It can be applied to the determination of the 23 ester compounds in cigarette water-borne adhesives.

  5. The association of drinking water quality and sewage disposal with Helicobacter pylori incidence in infants: the potential role of water-borne transmission.

    Science.gov (United States)

    Travis, Penny B; Goodman, Karen J; O'Rourke, Kathleen M; Groves, Frank D; Sinha, Debajyoti; Nicholas, Joyce S; VanDerslice, Jim; Lackland, Daniel; Mena, Kristina D

    2010-03-01

    The mode of transmission of Helicobacter pylori, a bacterium causing gastric cancer and peptic ulcer disease, is unknown although waterborne transmission is a likely pathway. This study investigated the hypothesis that access to treated water and a sanitary sewerage system reduces the H. pylori incidence rate, using data from 472 participants in a cohort study that followed children in Juarez, Mexico, and El Paso, Texas, from April 1998, with caretaker interviews and the urea breath test for detecting H. pylori infection at target intervals of six months from birth through 24 months of age. The unadjusted hazard ratio comparing bottled/vending machine water to a municipal water supply was 0.71 (95% confidence interval (CI): 0.50, 1.01) and comparing a municipal sewer connection to a septic tank or cesspool, 0.85 (95% CI: 0.60, 1.20). After adjustment for maternal education and country, the hazard ratios decreased slightly to 0.70 (95% confidence interval: 0.49, 1.00) and 0.77 (95% confidence interval: 0.50, 1.21), respectively. These results provide moderate support for potential waterborne transmission of H. pylori.

  6. Effects of subchronic exposure to waterborne cadmium on H-P-I axis hormones and related genes in rare minnows (Gobiocypris rarus).

    Science.gov (United States)

    Liu, Xiao-Hong; Wang, Zhi-Jian; Jin, Li; Huang, Jing; Pu, De-Yong; Wang, De-Shou; Zhang, Yao-Guang

    2017-07-22

    The H (hypothalamic)-P (pituitary)-I (interrenal) axis is critical in the stress response and other activities of fish. To further investigate cadmium (Cd) toxicity on the H-P-I axis and to identify its potential regulatory genes in fish, the adult female rare minnows (Gobiocypris rarus) were exposed to subchronic (5weeks) levels of waterborne Cd in the present study. This kind of treatment caused dose-dependent decline in fish growth, with significance in the high dose group (100μg/L). Correspondingly, low dose (5-50μg/L) waterborne Cd disrupted the endocrine system of H-P-I axis just at the secretion level, while high dose Cd disrupted both the secretion and synthesis of cortisol and its downstream signals in rare minnows, revealed by the significantly upregulation and positive correlation of corticosteroidogenic genes including MC2R, StAR, CYP11A1, and CYP11B1 in the kidney (including the interrenal tissue) (PPP-I axis in fish. The expression of FKBP5 in the intestine was positively and significantly correlated with that of Hsp90AA (PP<0.05), which indicated that Hsp90AA and Hsp90AB were more likely to serve as cofactors of GR and FKBP5 in response to Cd exposure. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. 水性聚氨酯亲水性扩链剂的研究进展%Research progress in waterborne polyurethane hydrophilic chain extender

    Institute of Scientific and Technical Information of China (English)

    王学川; 任静; 强涛涛

    2014-01-01

    水性聚氨酯在涂料、医学、胶黏剂等领域都有着广泛的应用,而扩链剂是合成聚氨酯的一种关键原料。在扩链剂上引入某些特征基团就会对聚氨酯的性能产生一定的影响,亲水性扩链剂可以使水性聚氨酯具有良好的分散性或自乳化性能。羧酸型和磺酸型亲水扩链剂是目前使用较为普遍的阴离子型亲水扩链剂材料。该文简述了扩链剂的定义、作用以及亲水性扩链剂的种类,综述了羧酸型和磺酸型亲水扩链剂的研究进展,详细分析了磺酸型水性聚氨酯的高耐水性、高柔软性,高固含量等性能以及相比于羧酸型水性聚氨酯在各方面性能上的优势。文中还简述了非离子型亲水扩链剂和两性亲水扩链剂的研究进展,并就成本、合成路线及环保方面对亲水性扩链剂的发展趋势作了展望。%Waterborne polyurethane is widely used in many fields,such as coating,medicine and adhesive,and chain extender is one of the key raw materials for the synthesis of polyurethane. Groups introduced on the chain extender with certain characteristics will affect the performance of polyurethane,hydrophilic chain extender can provide waterborne polyurethane good dispersion and emulsification. Currently carboxylic acid and sulfonic acid hydrophilic chain extenders are commonly used materials of anionic chain extenders. In this paper,the definition and function of the chain extender,the kinds of hydrophilic chain extenders were briefly described. The research progress in carboxylic acid and sulfonic acid hydrophilic chain extenders were summarized,the differences in the performance of carboxylic acid and sulfonic acid of waterborne polyurethanes were analyzed in detail. The high water resistance,high flexibility,high solid content and other properties of sulfonic acid type waterborne polyurethane are analyzed in detail,and compared to carboxylic acid type waterborne polyurethane in the

  8. 聚氨酯多元醇水分散体的合成%Synthesis of Waterborne Polyurethane Polyol Dispersions

    Institute of Scientific and Technical Information of China (English)

    张旭东; 胡军保; 吴娇; 钱帆; 王雪

    2011-01-01

    A polyurethane polyol dispersions of two-package waterborne polyurethane have been successfully synthesized with diethanolamine (DEA) as the blocking agent for introducing hydroxy-terminated on to the end-NCO polyurethane prepolymers, which were prepared beforehand with isophorone diisocyanate (IPDI), polyether binary alcohol (N210), dimethylol propionic acid (DMPA), and trimethylolpropane(TMP) as the main raw materials.The properties of the dispersions and films such as gloss, hardness, solvent resistance, water resistance were significantly affected by the amount of DMPA, TMP, hydroxy contents and the ratio of dispersions to curing agents.The optimum performance was obtained with the content of DMPA, TMP and DEA reaching 6%~6.5%, 3%~5% and 7.61% respectively, and the ratio of curing agents to dispersions being 1.5~1.7.Furthermore, the synthetic process of the polyol dispersions and the 2K-WPU films were characterized by multiple devices such as FTIR and SEM.%以异佛尔酮二异氰酸酯(IPDI),聚醚二元醇(N210),二羟甲基丙酸(DMPA),三羟甲基丙烷(TMP)为主要原料制备端-NCO聚氨酯预聚体,用二乙醇胺(DEA)封端引入羟基,合成了双组分水性聚氨酯的聚氨酯多元醇分散体组分.研究发现:DMPA,TMP的用量、羟基含量及分散体与固化剂组分的配比等因素显著影响分散体及涂膜的性能.当DMPA质量分数为6%~6.5%,TMP质量分数为3%~5%,DEA质量分数为7.61%,nNC0:nOH为1.5~1.7时,涂膜的光泽度、硬度、耐溶剂性、耐水性等最佳.采用傅立叶变换红外光谱、扫描电镜等仪器对多元醇合成过程和双组分水性聚氨酯涂膜进行了表征.

  9. Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants

    Energy Technology Data Exchange (ETDEWEB)

    Michalec, François-Gaël [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Holzner, Markus [Institute of Environmental Engineering, ETH Zürich (Switzerland); Menu, Dominique [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); Hwang, Jiang-Shiou [National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Souissi, Sami, E-mail: sami.souissi@univ-lille1.fr [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France)

    2013-08-15

    increase in speed and activity resembles an escape reaction permitting copepods to evade stressful conditions. Overall, these results indicate that environment-relevant concentrations of pollutants can induce rapid changes in copepod behavior. Since behavioral processes represent a fundamental element in the ecology of copepods, our results raise concern about the effects of background levels of pollution on a major component of the plankton community. The long-term response of copepods to waterborne pollutants, their synergistic effects and their interactions with other environmental factors need further investigation.

  10. In situ fate and partitioning of waterborne perfluoroalkyl acids (PFAAs) in the Youngsan and Nakdong River Estuaries of South Korea

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Seongjin [School of Earth and Environmental Sciences, Seoul National University, Seoul (Korea, Republic of); Khim, Jong Seong, E-mail: jskocean@snu.ac.kr [School of Earth and Environmental Sciences, Seoul National University, Seoul (Korea, Republic of); Park, Jinsoon [School of Earth and Environmental Sciences, Seoul National University, Seoul (Korea, Republic of); Kim, Minhee; Kim, Woong-Ki; Jung, Jinho; Hyun, Seunghun; Kim, Jeong-Gyu [Division of Environmental Science and Ecological Engineering, Korea University, Seoul (Korea, Republic of); Lee, Hyojin; Choi, Heeseon J. [Department of Environmental Chemistry and Ecology, GeoSystem Research Corporation, Gunpo (Korea, Republic of); Codling, Garry [Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, SK (Canada); Giesy, John P. [Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan, Saskatoon, SK (Canada); Department of Zoology, Center for Integrative Toxicology, Michigan State University, East Lansing, MI (United States); Department of Biology and Chemistry and State Key Laboratory in Marine Pollution, City University of Hong Kong, Kowloon, Hong Kong, SAR (China)

    2013-02-15

    Concentrations, distributions, fate, and partitioning of perfluoroalkyl acids (PFAAs) were investigated in surface water (n = 34) collected from the Youngsan and Nakdong River Estuaries of South Korea. Thirteen individual PFAAs in water and suspended solids (SS) were quantified by use of HPLC–MS/MS. PFAAs were detected in all samples, which indicated that they were widely distributed in the study area. Greater concentrations of PFAAs were found at some inland sites which seemed to be affected by direct input from point sources, such as wastewater treatment plants, and/or indirect diffusive sources, such as surface runoff. Spatial distributions of PFAAs in estuaries along transects toward the open sea demonstrated that these chemicals were transported to the outer region primarily by water discharged during the rainy season. Field-based partition coefficients (K{sub d}) for long-chain PFAAs (C ≥ 8) were significantly correlated with salinity (r{sup 2} = 0.48 to 0.73, p < 0.01); K{sub d} values increased exponentially as a function of salinity. Due to the ‘salting-out’ effect, PFAAs were largely scavenged by adsorption onto SS and/or sediments in estuarine environments. In addition, values for K{sub d} of those PFAAs were directly proportional to the number of carbon atoms in the PFAAs. Salting constants of selected PFAAs were notably greater than those of other environmental organic contaminants, which indicated that adsorption of PFAAs is largely associated with salinity. Overall, the results of the present study will provide better understanding of the fate and transport of PFAAs in the zone of salinity boundary that can be used for developing fate models of PFAAs in the coastal marine environment. - Highlights: ► In situ fate and partitioning of PFAAs were described along salinity gradients in estuaries. ► Salinity was found to be the key factor controlling adsorption of waterborne PFAAs. ► The K{sub d} for longer-chain PFAAs (C ≥ 8) increased as

  11. Dynamics of Carroll particles

    NARCIS (Netherlands)

    Bergshoeff, Eric; Gomis, Joaquim; Longhi, Giorgio

    2014-01-01

    We investigate particles whose dynamics are invariant under the Carroll group. Although a single, free such Carroll particle has no non-trivial dynamics (the Carroll particle does not move), we show that non-trivial dynamics exists for a set of interacting Carroll particles. Furthermore, we gauge th

  12. Particle adhesion and removal

    CERN Document Server

    Mittal, K L

    2015-01-01

    The book provides a comprehensive and easily accessible reference source covering all important aspects of particle adhesion and removal.  The core objective is to cover both fundamental and applied aspects of particle adhesion and removal with emphasis on recent developments.  Among the topics to be covered include: 1. Fundamentals of surface forces in particle adhesion and removal.2. Mechanisms of particle adhesion and removal.3. Experimental methods (e.g. AFM, SFA,SFM,IFM, etc.) to understand  particle-particle and particle-substrate interactions.4. Mechanics of adhesion of micro- and  n

  13. Water-borne cues of a non-indigenous seaweed mediate grazer-deterrent responses in native seaweeds, but not vice versa.

    Science.gov (United States)

    Yun, Hee Young; Engelen, Aschwin H; Santos, Rui O; Molis, Markus

    2012-01-01

    Plants optimise their resistance to herbivores by regulating deterrent responses on demand. Induction of anti-herbivory defences can occur directly in grazed plants or from emission of risk cues to the environment, which modifies interactions of adjacent plants with, for instance, their consumers. This study confirmed the induction of anti-herbivory responses by water-borne risk cues between adjoining con-specific seaweeds and firstly examined whether plant-plant signalling also exists among adjacent hetero-specific seaweeds. Furthermore, differential abilities and geographic variation in plant-plant signalling by a non-indigenous seaweed as well as native seaweeds were assessed. Twelve-day induction experiments using the non-indigenous seaweed Sargassum muticum were conducted in the laboratory in Portugal and Germany with one local con-familiar (Portugal: Cystoseira humilis, Germany: Halidrys siliquosa) and hetero-familiar native species (Portugal: Fucus spiralis, Germany: F. vesiculosus). All seaweeds were grazed by a local isopod species (Portugal: Stenosoma nadejda, Germany: Idotea baltica) and were positioned upstream of con- and hetero-specific seaweeds. Grazing-induced modification in seaweed traits were tested in three-day feeding assays between cue-exposed and cue-free ( = control) pieces of both fresh and reconstituted seaweeds. Both Fucus species reduced their palatability when positioned downstream of isopod-grazed con-specifics. Yet, the palatability of non-indigenous S. muticum remained constant in the presence of upstream grazed con-specifics and native hetero-specifics. In contrast, both con-familiar (but neither hetero-familiar) native species reduced palatability when located downstream of grazed S. muticum. Similar patterns of grazer-deterrent responses to water-borne cues were observed on both European shores, and were almost identical between assays using fresh and reconstituted seaweeds. Hence, seaweeds may use plant-plant signalling to

  14. 水性胶粘剂中丙烯酰胺单体含量的测定%Testing acrylamide monomer contents in waterborne adhesives

    Institute of Scientific and Technical Information of China (English)

    孙行; 戴双燕

    2012-01-01

    To establish testing method for remaining AM (acrylamide) monomer in waterborne adhesives, namely , the AM monomer contents in extracted sample were tested by capillary column separation method, GC-FID(gas chromatography-hydrogen flameionization detector) method when the trichloromethane as good solvent could effectively extracte AM monomer in waterborne adhesives samples. The results showed that the reproducibility of testing AM contents in waterborne adhesive was good by above methods because its relative standard deviation was 0.3-2.8 mg/L when the concentration of standard sample was 5.0-80.0 mg/L. With construction-adhesive and white latex as example,the results of testing AM contents in adhesive samples by above methods were more reliable because the recovery rates of two samples(added between 93%—107%) were all good.%建立了水性胶粘剂口残留AM(丙烯酰胺)单体的检测方法,即首先利用良溶剂三氯甲烷有效提取水性胶粘剂样品中的AM单体,然后采用毛细管柱分离法、GC-FID(气相色谱-氢火焰离子化检测)法测定提出液中的AM含量.结果表明:当标准样品的浓度为5.0~80.0mg/L时,采用上述方法测定水性胶粘剂中AM含量时,其重复性良好(相对标准偏差为0.3~2.8mg/L);以某厂生产的建筑胶粘剂和白胶为例,采用上述方法测定胶样中的AM含量,两者的加标回收率为93%~107%,说明两种样品的回收率良好,其测试结果较为可靠.

  15. Water-borne cues of a non-indigenous seaweed mediate grazer-deterrent responses in native seaweeds, but not vice versa.

    Directory of Open Access Journals (Sweden)

    Hee Young Yun

    Full Text Available Plants optimise their resistance to herbivores by regulating deterrent responses on demand. Induction of anti-herbivory defences can occur directly in grazed plants or from emission of risk cues to the environment, which modifies interactions of adjacent plants with, for instance, their consumers. This study confirmed the induction of anti-herbivory responses by water-borne risk cues between adjoining con-specific seaweeds and firstly examined whether plant-plant signalling also exists among adjacent hetero-specific seaweeds. Furthermore, differential abilities and geographic variation in plant-plant signalling by a non-indigenous seaweed as well as native seaweeds were assessed. Twelve-day induction experiments using the non-indigenous seaweed Sargassum muticum were conducted in the laboratory in Portugal and Germany with one local con-familiar (Portugal: Cystoseira humilis, Germany: Halidrys siliquosa and hetero-familiar native species (Portugal: Fucus spiralis, Germany: F. vesiculosus. All seaweeds were grazed by a local isopod species (Portugal: Stenosoma nadejda, Germany: Idotea baltica and were positioned upstream of con- and hetero-specific seaweeds. Grazing-induced modification in seaweed traits were tested in three-day feeding assays between cue-exposed and cue-free ( = control pieces of both fresh and reconstituted seaweeds. Both Fucus species reduced their palatability when positioned downstream of isopod-grazed con-specifics. Yet, the palatability of non-indigenous S. muticum remained constant in the presence of upstream grazed con-specifics and native hetero-specifics. In contrast, both con-familiar (but neither hetero-familiar native species reduced palatability when located downstream of grazed S. muticum. Similar patterns of grazer-deterrent responses to water-borne cues were observed on both European shores, and were almost identical between assays using fresh and reconstituted seaweeds. Hence, seaweeds may use plant

  16. 环氧树脂改性水性硝化纤维胶黏剂的研究%Study on waterborne nitrocellulose adhesive modified by epoxy resin

    Institute of Scientific and Technical Information of China (English)

    蒋吉磊; 苏秀霞; 惠媛媛; 李仲谨

    2011-01-01

    Self-emulsified waterborne nitrocellulose emulsion is prepared with nitrocellulose ( NC), isophorone diisocyanate(IPDI) and dimethylol propionic acid(DMPA) as main materials,and then reacted with epoxy resin E-44. Waterborne nitrocellulose adhesive emulsion modified by epoxy resin is synthesized through the reaction between epoxy group and carboxyl. The effect of E-44 and DMPA content on the properties of adhesive is investigated by FT-IR.TEM, TGA and other testing means. The results show that when the mass fraction of E-44 and DMPA are 5% and 3. 5% respectively,the water resistance,thermal stability and flexibility of waterborne nitrocellulose adhesive modified by epoxy resin behave outstanding performance with 7.7 N/mm of bonding strength.%以硝化纤维(NC)、异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)等为主要原料,制得自乳化型水性硝化纤维乳液,再加入环氧树脂E-44,环氧基与羧基反应制备出环氧树脂改性的水性硝化纤维胶黏剂乳液.通过傅里叶变换红外光谱(FT-IR)、透射电子显微镜(TEM)、热失重分析(TGA)法等测试手段,研究了环氧树脂E-44和DMPA的含量对胶黏剂性能的影响.结果表明,当ω(环氧树脂E-44)=5%、ω(DMPA)=3.5%时,环氧树脂改性水性硝化纤维胶黏剂的耐水性、耐热性和柔韧性优异,粘接强度可达7.7 N/mm.

  17. Waterborne Diseases & Illnesses

    Science.gov (United States)

    ... It Algae Blooms (Tox Town - National Library of Medicine) - Describes the hazardous environmental effects of algae blooms. High Tides, Red Tides, and Not-so-White Water (Washington State Department of Health) - Describes problems such as flooding, diseases, and too much salt that result from high ...

  18. Waterborne Polymeric Films.

    Science.gov (United States)

    1981-02-01

    Skydrol 500B is a fire resistant hydraulic fluid available from Monsanto and which is primarily tricresyl phosphate. In most cases, the above table...Makromol. Chem. 1979, 82 149.- 23. Ger. Offen 2,804,609; (8/9/79). Bayer AG. 24. Odian, G. "Principles of Polymerization; "McGraw-Hill Book Co.: New York

  19. Biochemical biomarker responses of green-lipped mussel, Perna canaliculus, to acute and subchronic waterborne cadmium toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Chandurvelan, Rathishri, E-mail: rch118@uclive.ac.nz [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); Marsden, Islay D., E-mail: islay.marsden@canterbury.ac.nz [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); Gaw, Sally, E-mail: sally.gaw@canterbury.ac.nz [Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); Glover, Chris N., E-mail: chris.glover@canterbury.ac.nz [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand)

    2013-09-15

    Highlights: •Biochemical biomarkers were measured to assess effects of Cd on Perna canaliculus. •Biochemical responses varied between acute and subchronic exposure to Cd. •MTLP induction correlated strongly with Cd accumulation. •Alkaline phosphatase and glycogen levels decreased during subchronic Cd exposure. •Duration of Cd exposure influenced biochemical biomarker responses in mussels. -- Abstract: The biochemical responses of the green-lipped mussel, Perna canaliculus, to waterborne cadmium (Cd) were investigated in order to delineate toxic mechanisms, and the impacts of exposure dose and duration, of this important toxicant in a potential sentinel species. Mussels were exposed for either 96 h (acute: 0, 2000, 4000 μg L{sup −1} Cd) or for 28 d (subchronic: 0, 200, 2000 μg L{sup −1} Cd), and the digestive gland, gill and haemolymph were examined for impacts. Biochemical responses measured included those associated with metal detoxification (metallothionein-like protein; MTLP), oxidative stress (catalase, lipid peroxidation), cellular homeostasis (alkaline phosphatase, Na{sup +}, K{sup +}-ATPase; NKA), and energy utilisation (glycogen, haemolymph protein). Following acute exposure, digestive gland glycogen and gill NKA activity were significantly altered by Cd exposure relative to levels in mussels exposed to Cd-free seawater. Subchronic Cd exposure resulted in a significant increase in MTLP levels in both the gill and the digestive gland. This increase was correlated strongly with the levels of Cd accumulation measured in these tissues (R = 0.957 for gill, 0.964 for digestive gland). Catalase activity followed a similar pattern, although the correlation with tissue Cd accumulation was not as strong (R = 0.907 for gill, 0.708 for digestive gland) as that for MTLP. Lipid peroxidation increased in the digestive gland at Days 7 and 14 at both subchronic Cd levels tested, but this effect had largely dissipated by Days 21 and 28 (with the exception of

  20. 有机硅偶联剂改性水性聚氨酯的合成%Synthesis and application of waterborne polyurethane modified with organic silicon

    Institute of Scientific and Technical Information of China (English)

    张鹏; 赵振河; 张文博; 李密转

    2012-01-01

    The modified waterborne polyurethane (WPU) was synthesized by prepolymer-blocking combination.2,4-toluene diisocyanate (TDI) and polyther polyol (PEG-1000) carried out the prepolymerization.and then the prepolymer was blocked with silane coupling agent (A-110).The effect of modifying process conditions on WPU properties was discueeed.%采用预聚体——封端混合法,用2,4-甲苯二异氰酸酯(TDI)与聚醚多元醇(PEG-1000)进行预聚反应,同时用有机硅偶联剂(A-110)对聚氨酯改性.探讨改性工艺条件对水性聚氨酯性能的影响.

  1. Cognitive disparities, lead plumbing, and water chemistry: prior exposure to water-borne lead and intelligence test scores among World War Two U.S. Army enlistees.

    Science.gov (United States)

    Ferrie, Joseph P; Rolf, Karen; Troesken, Werner

    2012-01-01

    Higher prior exposure to water-borne lead among male World War Two U.S. Army enlistees was associated with lower intelligence test scores. Exposure was proxied by urban residence and the water pH levels of the cities where enlistees lived in 1930. Army General Classification Test scores were six points lower (nearly 1/3 standard deviation) where pH was 6 (so the water lead concentration for a given amount of lead piping was higher) than where pH was 7 (so the concentration was lower). This difference rose with time exposed. At this time, the dangers of exposure to lead in water were not widely known and lead was ubiquitous in water systems, so these results are not likely the effect of individuals selecting into locations with different levels of exposure. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. 水性木器涂料在工业涂装中的应用%Use of Water-borne Woodenware Coatings in Industrial Application

    Institute of Scientific and Technical Information of China (English)

    王德华; 朱强; 胡中源; 罗先平

    2011-01-01

    介绍了水性木器涂料及木材的基本特点,根据水性木器涂料和木材的这些特点选择合适的工业涂装领域(例如儿童玩具、套房家具、木质餐椅、木质窗框、室内木门以及木质地板的涂装等)和涂装工艺,可以更好地使水性木器涂料在工业中得到合理广泛的应用。%This paper introduces the basic characteristics of water-borne woodenware coatings and wood, and based on these, how to use the coatings in suitable industrial fields (such as children toys, furniture of suite, wooden dining chair, wooden window frame, wo

  3. Research progress of waterborne polyurethane modified by organic silicon%有机硅改性水性聚氨酯研究进展

    Institute of Scientific and Technical Information of China (English)

    王刚; 侯彩英; 马国章; 凌丽霞

    2013-01-01

    介绍了有机硅改性水性聚氨酯(WPU)的特点,综述了近年来有机硅封端、嵌段共聚及其与丙烯酸酯复合改性制备有机硅改性WPU的研究进展;最后对有机硅改性WPU的研究方向进行了展望.%The characteristics of waterborne polyurethane(WPU) modified by organic silicon were introduced.The research progresses of preparing WPU modified by organic silicon (including modified by organic siliconterminated,modified by organic silicon with block copolymer,and modified by organic silicon and acrylate) were summarized in recent years.Finally,the research directions of WPU modified by organic silicon were expected.

  4. A CCD-based fluorescence imaging system for real-time loop-mediated isothermal amplification-based rapid and sensitive detection of waterborne pathogens on microchips.

    Science.gov (United States)

    Ahmad, Farhan; Seyrig, Gregoire; Tourlousse, Dieter M; Stedtfeld, Robert D; Tiedje, James M; Hashsham, Syed A

    2011-10-01

    Rapid, sensitive, and low-cost pathogen diagnostic systems are needed for early disease diagnosis and treatment, especially in resource-limited settings. This study reports a low-cost charge-coupled device (CCD)-based fluorescence imaging system for rapid detection of waterborne pathogens by isothermal gene amplification in disposable microchips. Fluorescence imaging capability of this monochromatic CCD camera is evaluated by optimizing the gain, offset, and exposure time. This imaging system is validated for 12 virulence genes of major waterborne pathogens on cyclic olefin polymer (COP) microchips, using SYTO-82 dye and real time fluorescence loop-mediated isothermal amplification referred here as microRT(f)-LAMP. Signal-to-noise ratio (SNR) and threshold time (Tt) of microRT(f)-LAMP assays are compared with those from a commercial real-time polymerase chain reaction (PCR) instrument. Applying a CCD exposure of 5 s to 10(5) starting DNA copies of microRT(f)-LAMP assays increases the SNR by 8-fold and reduces the Tt by 9.8 min in comparison to a commercial real-time PCR instrument. Additionally, single copy level sensitivity for Campylobacter jejuni 0414 gene is obtained for microRT(f)-LAMP with a Tt of 19 min, which is half the time of the commercial real-time PCR instrument. Due to the control over the exposure time and the wide field imaging capability of CCD, this low-cost fluorescence imaging system has the potential for rapid and parallel detection of pathogenic microorganisms in high throughput microfluidic chips.

  5. Particle physics: Axions exposed

    Science.gov (United States)

    Lombardo, Maria Paola

    2016-11-01

    Physicists are hunting for a particle called the axion that could solve two major puzzles in fundamental physics. An ambitious study calculates the expected mass of this particle, which might reshape the experimental searches. See Letter p.69

  6. Beyond the God particle

    CERN Document Server

    Lederman, Leon M

    2013-01-01

    On July 4, 2012, the long-sought Higgs Boson--aka "the God Particle"--was discovered at the world's largest particle accelerator, the LHC, in Geneva, Switzerland. On March 14, 2013, physicists at CERN confirmed it. This elusive subatomic particle forms a field that permeates the entire universe, creating the masses of the elementary particles that are the basic building blocks of everything in the known world--from viruses to elephants, from atoms to quasars.

  7. Multiscale Simulations Using Particles

    DEFF Research Database (Denmark)

    Walther, Jens Honore

    We are developing particle methods as a general framework for large scale simulations of discrete and continuous systems in science and engineering. The specific application and research areas include: discrete element simulations of granular flow, smoothed particle hydrodynamics and particle...... vortex methods for problems in continuum fluid dynamics, dissipative particle dynamics for flow at the meso scale, and atomistic molecular dynamics simulations of nanofluidic systems. We employ multiscale techniques to breach the atomistic and continuum scales to study fundamental problems in fluid...

  8. When is a Particle?

    Science.gov (United States)

    Drell, Sidney D.

    1978-01-01

    Gives a new definition for the concept of the elementary particle in nuclear physics. Explains why the existance of the quark as an elementary particle could be an accepted fact even though it lacks what traditionally identifies a particle. Compares this with the development which took place during the discovery of the neutrino in the early…

  9. Massless interacting particles

    Energy Technology Data Exchange (ETDEWEB)

    Kosyakov, B P [Russian Federal Nuclear Center, Sarov, 607190 Nizhnii Novgorod Region (Russian Federation)], E-mail: kosyakov@vniief.ru

    2008-11-21

    We show that classical electrodynamics of massless charged particles and the Yang-Mills theory of massless quarks do not experience rearranging their initial degrees of freedom into dressed particles and radiation. Massless particles do not radiate. We propose a conformally invariant version of the direct interparticle action theory for these systems.

  10. Atomic Particle Detection

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1970-01-01

    This booklet tells how scientists observe the particles and electromagnetic radiation that emerges from an atomic nucleus. The equipment used falls into two general categories: counters which count each particle as it passes by, and track detectors, which make a photographic record of the particle's track.

  11. Light scattering by cosmic particles

    NARCIS (Netherlands)

    Hovenier, J.W.; Min, M.

    2008-01-01

    We define cosmic particles as particles outside the Earth. Two types of cosmic particles can be distinguished, namely liquid and solid particles. The solid particles are often called grains or cosmic dust particles. Cosmic particles occur in a great variety of astronomical objects and environments.

  12. Primordial Particles; Collisions of Inelastic Particles

    Science.gov (United States)

    Sagi, George

    2011-03-01

    Three-dimensional matter is not defined by Euclidian or Cartesian geometries. Newton's and Einstein's laws are related to the motions of elastic masses. The study of collisions of inelastic particles opens up new vistas in physics. The present article reveals how such particles create clusters composed of various numbers of particles. The Probability of each formation, duplets, triplets, etc. can be calculated. The particles are held together by a binding force, and depending upon the angles of collisions they may also rotate around their center of geometry. Because of these unique properties such inelastic particles are referred to as primordial particles, Pp. When a given density of Pp per cubic space is given, then random collisions create a field. The calculation of the properties of such primordial field is very complex and beyond the present study. However, the angles of collisions are infinite in principle, but the probabilities of various cluster sizes are quantum dependent. Consequently, field calculations will require new complex mathematical methods to be discovered yet.

  13. Formulation and shelf life stability of water-borne lecithin nanoparticles for potential application in dietary supplements field.

    Science.gov (United States)

    Edris, Amr E

    2012-09-01

    ABSTRACT The objective of the present investigation is to formulate commercial soybean lecithin as nanoparticles in solvent-free aqueous system for potential supplementary applications. A mechanical method, which involved two major steps, was used for that purpose. First, lecithin submicron particles (~ 0.5 μm) have been prepared by gradual hydration of lecithin powder using mechanical agitation. Finally, the size of these particles was further reduced to lecithin nanoparticles were assessed every 15 days during the 3-month shelf life period at two different temperatures. Results showed that the final particle size of lecithin in the freshly prepared aqueous dispersion was 79.8 ± 1.0 nm and the amount of peroxide detected was 3.5 ± 0.2 meq/kg lipid. At the end of the storage period, dispersions stored at 4°C exhibited physical and chemical stability as evident from the translucent appearance, the small change in particle size (84.1 ± 1.3 nm), and the small amount of generated peroxides (4.1 ± 0.2 meq/kg lipid). On the other hand, dispersions stored at 25°C were physically stable up to 60 days. Over that period, samples became turbid and the particle size increased to 145.0 ± 1.7 nm with a bimodal distribution pattern. This behavior was due to phospholipids (PLs) degradation and hydrolysis under acidic conditions, which proceeds faster at a relatively high temperature (25°C) than at (4°C). The outcome of this investigation may help in developing water-based dispersions carrying lecithin nanoparticles for dietary supplement of PLs.

  14. The Particle Enigma

    CERN Document Server

    Marsh, Gerald E

    2016-01-01

    The idea that particles are the basic constituents of all matter dates back to ancient times and formed the basis of physical thought well into modern times. The debate about whether light was a wave or a stream of particles also lasted until relatively recently. It was the advent of de Broglie's work and its implications that revolutionized the concept of an elementary particle -- but unfortunately did not banish the idea of a point particle despite its difficulties in both classical and quantum physics. Some of these problems are discussed in this essay, which covers chiral oscillations, Penrose's "zigzag" picture of particles satisfying the Dirac equation, and some ideas derived from string theory.

  15. Particle Accelerators in China

    Science.gov (United States)

    Zhang, Chuang; Fang, Shouxian

    As the special machines that can accelerate charged particle beams to high energy by using electromagnetic fields, particle accelerators have been widely applied in scientific research and various areas of society. The development of particle accelerators in China started in the early 1950s. After a brief review of the history of accelerators, this article describes in the following sections: particle colliders, heavy-ion accelerators, high-intensity proton accelerators, accelerator-based light sources, pulsed power accelerators, small scale accelerators, accelerators for applications, accelerator technology development and advanced accelerator concepts. The prospects of particle accelerators in China are also presented.

  16. Fluidization of spherocylindrical particles

    Science.gov (United States)

    Mahajan, Vinay V.; Nijssen, Tim M. J.; Fitzgerald, Barry W.; Hofman, Jeroen; Kuipers, Hans; Padding, Johan T.

    2017-06-01

    Multiphase (gas-solid) flows are encountered in numerous industrial applications such as pharmaceutical, food, agricultural processing and energy generation. A coupled computational fluid dynamics (CFD) and discrete element method (DEM) approach is a popular way to study such flows at a particle scale. However, most of these studies deal with spherical particles while in reality, the particles are rarely spherical. The particle shape can have significant effect on hydrodynamics in a fluidized bed. Moreover, most studies in literature use inaccurate drag laws because accurate laws are not readily available. The drag force acting on a non-spherical particle can vary considerably with particle shape, orientation with the flow, Reynolds number and packing fraction. In this work, the CFD-DEM approach is extended to model a laboratory scale fluidized bed of spherocylinder (rod-like) particles. These rod-like particles can be classified as Geldart D particles and have an aspect ratio of 4. Experiments are performed to study the particle flow behavior in a quasi-2D fluidized bed. Numerically obtained results for pressure drop and bed height are compared with experiments. The capability of CFD-DEM approach to efficiently describe the global bed dynamics for fluidized bed of rod-like particles is demonstrated.

  17. Fluidization of spherocylindrical particles

    Directory of Open Access Journals (Sweden)

    Mahajan Vinay V.

    2017-01-01

    Full Text Available Multiphase (gas-solid flows are encountered in numerous industrial applications such as pharmaceutical, food, agricultural processing and energy generation. A coupled computational fluid dynamics (CFD and discrete element method (DEM approach is a popular way to study such flows at a particle scale. However, most of these studies deal with spherical particles while in reality, the particles are rarely spherical. The particle shape can have significant effect on hydrodynamics in a fluidized bed. Moreover, most studies in literature use inaccurate drag laws because accurate laws are not readily available. The drag force acting on a non-spherical particle can vary considerably with particle shape, orientation with the flow, Reynolds number and packing fraction. In this work, the CFD-DEM approach is extended to model a laboratory scale fluidized bed of spherocylinder (rod-like particles. These rod-like particles can be classified as Geldart D particles and have an aspect ratio of 4. Experiments are performed to study the particle flow behavior in a quasi-2D fluidized bed. Numerically obtained results for pressure drop and bed height are compared with experiments. The capability of CFD-DEM approach to efficiently describe the global bed dynamics for fluidized bed of rod-like particles is demonstrated.

  18. Particle separator scroll vanes

    Energy Technology Data Exchange (ETDEWEB)

    Lastrina, F. A.; Mayer, J. C.; Pommer, L. M.

    1985-07-09

    An inlet particle separator for a gas turbine engine is provided with unique vanes distributed around an entrance to a particle collection chamber. The vanes are uniquely constructed to direct extraneous particles that enter the engine into the collection chamber and prevent the particles from rebounding back into the engine's air flow stream. The vanes are provided with several features to accomplish this function, including upstream faces that are sharply angled towards air flow stream direction to cause particles to bounce towards the collection chamber. In addition, throat regions between the vanes cause a localized air flow acceleration and a focusing of the particles that aid in directing the particles in a proper direction.

  19. Adhesive particle shielding

    Science.gov (United States)

    Klebanoff, Leonard Elliott; Rader, Daniel John; Walton, Christopher; Folta, James

    2009-01-06

    An efficient device for capturing fast moving particles has an adhesive particle shield that includes (i) a mounting panel and (ii) a film that is attached to the mounting panel wherein the outer surface of the film has an adhesive coating disposed thereon to capture particles contacting the outer surface. The shield can be employed to maintain a substantially particle free environment such as in photolithographic systems having critical surfaces, such as wafers, masks, and optics and in the tools used to make these components, that are sensitive to particle contamination. The shield can be portable to be positioned in hard-to-reach areas of a photolithography machine. The adhesive particle shield can incorporate cooling means to attract particles via the thermophoresis effect.

  20. Fuzzy Logic Particle Tracking

    Science.gov (United States)

    2005-01-01

    A new all-electronic Particle Image Velocimetry technique that can efficiently map high speed gas flows has been developed in-house at the NASA Lewis Research Center. Particle Image Velocimetry is an optical technique for measuring the instantaneous two component velocity field across a planar region of a seeded flow field. A pulsed laser light sheet is used to illuminate the seed particles entrained in the flow field at two instances in time. One or more charged coupled device (CCD) cameras can be used to record the instantaneous positions of particles. Using the time between light sheet pulses and determining either the individual particle displacements or the average displacement of particles over a small subregion of the recorded image enables the calculation of the fluid velocity. Fuzzy logic minimizes the required operator intervention in identifying particles and computing velocity. Using two cameras that have the same view of the illumination plane yields two single exposure image frames. Two competing techniques that yield unambiguous velocity vector direction information have been widely used for reducing the single-exposure, multiple image frame data: (1) cross-correlation and (2) particle tracking. Correlation techniques yield averaged velocity estimates over subregions of the flow, whereas particle tracking techniques give individual particle velocity estimates. For the correlation technique, the correlation peak corresponding to the average displacement of particles across the subregion must be identified. Noise on the images and particle dropout result in misidentification of the true correlation peak. The subsequent velocity vector maps contain spurious vectors where the displacement peaks have been improperly identified. Typically these spurious vectors are replaced by a weighted average of the neighboring vectors, thereby decreasing the independence of the measurements. In this work, fuzzy logic techniques are used to determine the true

  1. The Research Situation and the Progress of Functional Waterborne Polyurethane Building Coatings%功能型水性聚氨酯建筑涂料的研究现状和最新进展∗

    Institute of Scientific and Technical Information of China (English)

    许凯翔; 杨建军

    2016-01-01

    综述了近几年功能型水性聚氨酯在建筑涂料中的应用现状和最新进展,主要包括防霉杀菌、防腐蚀、阻燃、防涂鸦、节能环保等特殊性能的水性聚氨酯功能型涂料;展望了功能型水性聚氨酯建筑涂料的发展前景。%The latest progress in functional waterborne polyurethane coatings in the field of building was intro⁃duced, including antimicrobial coatings, anticorrosive coatings, flame retardant coatings, anti⁃graffiti coatings and environment⁃friendly coatings, etc. The application prospect of waterborne polyurethane building coatings was pros⁃pected.

  2. 丙烯酸酯改性水性聚氨酯复合乳液的研究进展%Research progress of acrylate-modified waterborne polyurethane composite emulsion

    Institute of Scientific and Technical Information of China (English)

    施建刚; 田呈呈; 杨少艳; 赵振河

    2014-01-01

    综介绍了丙烯酸酯改性水性聚氨酯的几种改性制备方法及其优缺点,其中包括:物理共混改性,交联共混改性,接枝共聚改性,核-壳结构乳液聚合改性,互穿网络法改性等。综述了国内外的研究现状及今后研究发展方向。%The preparation methods and their relative merits of the acrylate-modified waterborne polyurethanes were given, including the physical blending,blend crosslinking,graft copolymerization,core-shell emulsion polymerization modifying and interpenetration network modifying.The domestic and foreign research status was summarized and the further development direction was pointed out for the research of acrylate-modified waterborne polyurethane emulsions.

  3. 包装复合膜用松香改性水性聚氨酯胶粘剂%Waterborne Polyurethane Adhesive Modified by Rosin for Laminated Package Films

    Institute of Scientific and Technical Information of China (English)

    郭文杰; 傅和青; 黄洪; 陈焕钦

    2007-01-01

    The waterborne polyurethane adhesive was modified by rosin. Effects of the amounts of DMPA,rosin, and NCO / OH value on the properties of the emulsion were studied. The adhesive property of modified and unmodified polyurethane for laminated package films was compared. And the experimental results showed that the modified waterborne polyurethane adhesive meets the need of laminated package films.%利用松香改性水性聚氨酯胶粘剂,研究了二羟甲基丙酸(DMPA)用量、NCO/OH值、松香用量对乳液性能的影响,比较了改性前后该胶粘荆对多种塑料薄膜的粘接性能.实验结果表明改性后的胶粘剂对多种塑料薄膜具有较强的粘接能力.

  4. Application of Microwave Drying in Two - Component Waterborne Polyurethane Wood Coatings%微波干燥应用于双组分水性聚氨酯木器漆的干燥过程

    Institute of Scientific and Technical Information of China (English)

    吴海生; 黄卫; 施国萍; 高建东

    2011-01-01

    Drying problem is a long - standing choke point for the industrialized application of two - component waterborne polyurethane.In this paper, microwave drying was adopted in the drying process of two component waterborne polyurethane coatings.This broke through the traditional viewpoint that the microwave drying could only be used in the drying process of one - component waterborne polyurethane coatings.The results showed that the film performance of the two - component waterborne polyurethane coating dried by the microwave was slightly better than that dried at room temperature, which was comparable to the benchmark - traditional solventborne polyurethane coating.In addition, the dosage of the curing agent was decreased.%干燥问题是长期以来制约水性双组分聚氨酯木器涂料工业化应用的瓶颈.将微波干燥应用于水性双组分聚氨酯木器涂料的干燥过程,打破了微波干燥只能应用于水性单组分涂料的传统观念,实验结果表明:水性双组分聚氨酯木器涂料经微波干燥形成的漆膜性能略高于常温干燥形成的漆膜,可与溶剂型双组聚氨酯木器涂料相媲美,且固化剂用量减少.

  5. Particle Swarm Optimization

    Science.gov (United States)

    Venter, Gerhard; Sobieszczanski-Sobieski Jaroslaw

    2002-01-01

    The purpose of this paper is to show how the search algorithm known as particle swarm optimization performs. Here, particle swarm optimization is applied to structural design problems, but the method has a much wider range of possible applications. The paper's new contributions are improvements to the particle swarm optimization algorithm and conclusions and recommendations as to the utility of the algorithm, Results of numerical experiments for both continuous and discrete applications are presented in the paper. The results indicate that the particle swarm optimization algorithm does locate the constrained minimum design in continuous applications with very good precision, albeit at a much higher computational cost than that of a typical gradient based optimizer. However, the true potential of particle swarm optimization is primarily in applications with discrete and/or discontinuous functions and variables. Additionally, particle swarm optimization has the potential of efficient computation with very large numbers of concurrently operating processors.

  6. Methods for forming particles

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Robert V.; Zhang, Fengyan; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin

    2016-06-21

    Single source precursors or pre-copolymers of single source precursors are subjected to microwave radiation to form particles of a I-III-VI.sub.2 material. Such particles may be formed in a wurtzite phase and may be converted to a chalcopyrite phase by, for example, exposure to heat. The particles in the wurtzite phase may have a substantially hexagonal shape that enables stacking into ordered layers. The particles in the wurtzite phase may be mixed with particles in the chalcopyrite phase (i.e., chalcopyrite nanoparticles) that may fill voids within the ordered layers of the particles in the wurtzite phase thus produce films with good coverage. In some embodiments, the methods are used to form layers of semiconductor materials comprising a I-III-VI.sub.2 material. Devices such as, for example, thin-film solar cells may be fabricated using such methods.

  7. Methods for forming particles

    Science.gov (United States)

    Fox, Robert V.; Zhang, Fengyan; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin

    2016-06-21

    Single source precursors or pre-copolymers of single source precursors are subjected to microwave radiation to form particles of a I-III-VI.sub.2 material. Such particles may be formed in a wurtzite phase and may be converted to a chalcopyrite phase by, for example, exposure to heat. The particles in the wurtzite phase may have a substantially hexagonal shape that enables stacking into ordered layers. The particles in the wurtzite phase may be mixed with particles in the chalcopyrite phase (i.e., chalcopyrite nanoparticles) that may fill voids within the ordered layers of the particles in the wurtzite phase thus produce films with good coverage. In some embodiments, the methods are used to form layers of semiconductor materials comprising a I-III-VI.sub.2 material. Devices such as, for example, thin-film solar cells may be fabricated using such methods.

  8. LHCb unveils new particles

    CERN Multimedia

    Stefania Pandolfi

    2016-01-01

    The LHCb collaboration announces the observation of four “exotic” particles from its analysis of the LHC data.   The LHCb experimental cavern. On 28 June, the LHCb collaboration reported the observation of three new "exotic" particles and confirmation of the existence of a fourth one in data from the LHC. These particles each appear to be formed by four quarks (the fundamental constituents of the matter inside all the atoms of the universe): two quarks and two antiquarks (that is, a tetraquark). Due to their non-standard quark content, the newly observed particles have been included in the broad category of so-called exotic particles, although their exact theoretical interpretation is still under study.            The quark model, proposed by Murray Gell-Mann and George Zweig in 1964, is considered to be the most valid scheme for the classification of hadrons (all the composite particles) that has been fou...

  9. Study on Synthesis and Stability of the Waterborne Blocked Isocyanate Emulsion%水性封闭异氰酸酯乳液的合成及稳定性研究

    Institute of Scientific and Technical Information of China (English)

    李阿峰; 樊国栋; 李会宁; 陈华; 赵琪

    2013-01-01

    Waterborne blocked isocyanate emulsion (WBI) was synthesized with toluene 2, 4 -diisocya-nate (TDI) , trimethylolpropane (TMP) , dimethylol propionic acid (DMPA) as the reaetants and 2 -meth-ylimidazole ( 2 - MI) as blocked agents and triethylamine as nentralizer. The influence of neutralizer and Ze-ta potential on stability of WBI emulsion was studied. The hydrolyte resistance and temperature dependence of emulsion and unblocking temperature of WBI and properties of two - component polyurethane film were discussed. The results showed that when triethylamine (TEA) was used as neutralizer, the emulsion provid-ed good stability and storage stability due to the small particle size. When the neutralization was up to 100% , the stability of emulsion was the best. With the increase of DMPA, the stability of the emulsion was improved. The Zeta potential and particle sized were less influenced by temperature. Suitable mole fraction of DMPA is 20%~25%. The unblocking temperature was 125. 6℃ to 137. 8℃ by DSC test. The WBI could be used as curing agent to provide better water resistance, alcohol resistance, hardness and impact proverties of coatings.%采用甲苯二异氰酸酯(TDI)、三羟甲基丙烷(TMP)、二羟甲基丙酸(DMPA)为原料,2-甲基咪唑为封闭剂,三乙胺为中和剂制备了水分散封闭异氰酸酯(WBI)乳液,考察了中和剂和Zeta电位(ξ-电位)对WBI乳液稳定性的影响,探讨了乳液耐电解质能力及其温敏特性对其解封温度及双组分聚氨酯漆膜性能的影响.实验结果表明:用三乙胺作为中和剂时,乳液粒径较小,稳定性及贮存稳定性均较好,最佳中和度为100%.随DMPA用量的增加,乳液的ξ电位绝对值增大,乳液粒径减小、耐电解质能力增强,乳液的稳定性提高.乳液的Zeta电位及粒径受温度影响较小,说明乳液较为稳定.DMPA用量为20% ~ 25%(摩尔分数)较适宜.差示扫描量热法(DSC)分析表征其解封温度为125.6 ~ 138.1

  10. Organic Modification of Nano-montmorillonite and Its Application in Waterborne Polyurethane%纳米蒙脱土有机改性及其在水性聚氨酯中的应用

    Institute of Scientific and Technical Information of China (English)

    李荣; 李兴建; 孙道兴

    2011-01-01

    介绍了纳米蒙脱土的结构、有机化改性剂的种类和有机改性纳米蒙脱土的制备方法;简述水性聚氨酯-蒙脱土纳米复合材料的制备,综述了有机化蒙脱土在改性水性聚氨酯中的应用,并对该类水性聚氨酯涂料的发展趋势和应用前景进行了展望。%The structure,type of organic modifiers and preparation method of organic nano-montmorillonite were introduced.The preparation of waterborne polyurethane-montmorillonite nano-composites and the application of organic modification of nano-montmorillonite in waterborne polyurethane were introduced,respectively.And the developing trends and application of this kind of waterborne polyurethane coatings were proposed.

  11. Development of Internal Emulsification Anion Waterborne Polyurethane Leather Finishes%内乳化阴离子水性聚氨酯皮革涂饰剂的研究进展

    Institute of Scientific and Technical Information of China (English)

    吕维忠; 涂伟萍; 陈焕钦

    2001-01-01

    The properties, the methods and theory of the preparation, and the development of the internal emulsification anion waterborne polyurethane leather finishes are reviewed in this paper.The possible developing .trends ofleather finishes are pointed out that the single component leather protective coating will be forwarded to coatings of multi - binders combination and multiple functions. The one - pack leather protective coating will be transited to the two - pack leather finishes The study of the two- pack waterborne polyurethane and the modified waterborne polyurethane leather finishes will be thc emphases and focus in the near future.%本文综述了内乳化阴离产水性聚氨酯皮革涂饰剂的性能特点、制备方法和原理以及国内外近期研究进展。指出水性聚氨酯皮革涂饰剂的发展趋势为:单一型向复合型、多功能涂饰剂发展;单组分向双组分涂饰剂过渡。双组分水性聚氨酯及改性水性聚氨酯皮革涂饰剂是近期研究的重点和热点。

  12. Preparation and Performance Research on Polyurethanes Waterborne Coating with Improved UVC Yellowing Resistance by Bisphenol S%双酚S耐黄变聚氨酯水性涂料的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    宋丽; 宋宇; 王亚茜

    2016-01-01

    As the bisphenol S could improve the UVC yellowing resistance of polyurethane material, with polyester polyol/polyether polyol substituted by bisphenol S, polyurethanes waterborne coating was prepared in this paper. Value of chromatism, tensile strength, elongation at break, hardness and light-induced weight loss of bisphenol S polyurethanes waterborne coating were compared with polyester polyol polyurethanes. Results showed that, bisphenol S polyurethanes waterborne coating had improved the UVC yellowing resistance.%利用双酚S替代传统的聚酯多元醇或聚醚多元醇制备聚氨酯水性涂料,可以提高其耐黄变性能。本文利用双酚S制备了聚氨酯耐黄变涂料,并对其色差值、拉伸强度、断裂伸长率、硬度以及光失重进行了对比研究,证明其具有良好的耐黄变性。

  13. Massless interacting particles

    CERN Document Server

    Kosyakov, B P

    2007-01-01

    We show that classical electrodynamics of massless charged particles and the Yang--Mills--Wong theory of massless quarks do not experience rearranging their initial degrees of freedom into dressed particles and radiation. Massless particles do not radiate. We propose a version of the direct interparticle action theory for such systems, which offers promise as a useful tool in studying the physics of quark-gluon plasma.

  14. Music of elementary particles

    Energy Technology Data Exchange (ETDEWEB)

    Sternheimer, J.

    1983-12-12

    This note offers a new point of view on particle masses. It is shown that they are distributed following a musical scale, the chromatic tempered scale -for stable particles- subdivided into microintervals including unstable particles. A theoretical explanation, based on causality, allows one also to calculate their global distribution along the mass scale, in agreement with experiment, and indicating the existence of ''musical'' laws in the vibratory organisation of matter.

  15. Multiscale Simulations Using Particles

    DEFF Research Database (Denmark)

    Walther, Jens Honore

    We are developing particle methods as a general framework for large scale simulations of discrete and continuous systems in science and engineering. The specific application and research areas include: discrete element simulations of granular flow, smoothed particle hydrodynamics and particle vor...... dynamics. Recent work on the thermophoretic motion of water nanodroplets confined inside carbon nanotubes, and multiscale techniques for polar liquids will be discussed in detail at the symposium....... vortex methods for problems in continuum fluid dynamics, dissipative particle dynamics for flow at the meso scale, and atomistic molecular dynamics simulations of nanofluidic systems. We employ multiscale techniques to breach the atomistic and continuum scales to study fundamental problems in fluid...

  16. Particle Correlations at LEP

    CERN Document Server

    Kress, Thomas

    2002-01-01

    Particle correlations are extensively studied to obtain information about the dynamics of hadron production. From 1989 to 2000 the four LEP collaborations recorded more than 16 million hadronic Z0 decays and several thousand W+W- events. In Z0 decays, two-particle correlations were analysed in detail to study Bose-Einstein and Fermi-Dirac correlations for various particle species. In fully-hadronic W+W- decays, particle correlations were used to study whether the two W bosons decay independently. A review of selected results is presented.

  17. Particle Physics & Astrophysics (PPA)

    Data.gov (United States)

    Federal Laboratory Consortium — Scientists at SLAC's Particle Physics and Astrophysics develop and utilize unique instruments from underground to outer space to explore the ultimate laws of nature...

  18. Bioactivation of particles

    Energy Technology Data Exchange (ETDEWEB)

    Pinaud, Fabien (Berkeley, CA); King, David (San Francisco, CA); Weiss, Shimon (Los Angeles, CA)

    2011-08-16

    Particles are bioactivated by attaching bioactivation peptides to the particle surface. The bioactivation peptides are peptide-based compounds that impart one or more biologically important functions to the particles. Each bioactivation peptide includes a molecular or surface recognition part that binds with the surface of the particle and one or more functional parts. The surface recognition part includes an amino-end and a carboxy-end and is composed of one or more hydrophobic spacers and one or more binding clusters. The functional part(s) is attached to the surface recognition part at the amino-end and/or said carboxy-end.

  19. Southern California Particle Center

    Data.gov (United States)

    Federal Laboratory Consortium — At the Southern California Particle Center, center researchers will investigate the underlying mechanisms that produce the health effects associated with exposure to...

  20. Evaluation of primitive ground water supplies as a risk factor for the development of major waterborne zoonosis in Egyptian children living in rural areas.

    Science.gov (United States)

    Elfadaly, Hassan A; Hassanain, Nawal A; Hassanain, Mohey A; Barakat, Ashraf M; Shaapan, Raafat M

    2017-08-23

    Endemic waterborne zoonosis frequently occurs in both developed and less developed countries. Thus, bio-surveillance of waterborne zoonosis is a "necessity" for the implementation of effective preventive public health measures in Egyptian rural areas. The primitive individual water supplies created by the rural agriculture population, primarily from ground water, usually maximize the customers' exposure to impurity pathogens via diffused humans and animal excreta or wastages. The current study aimed to evaluate the frequency of zoonotic pathogens within the infiltrated untreated ground water supplies with an assessment of the impact of such biohazards on children living in the studied Egyptian rural areas. A total of 796 stool samples were collected from children under 10 years of age from the Abulnomorous (401) and Shabramant (395) villages in Giza, Egypt, and two hundred forty five ground water samples were collected from various individual home water supplies (ground pumps) within two rural Egyptian localities, namely, the Abulnomorous (128) and Shabramant (117) villages. All the samples were examined for the identification of bacterial, fungal and parasitic zoonosis. The isolation of Campylobacter jejuni, Escherichia coli, Salmonella typhi and Shigella spp. was documented in the following frequencies in the water and stool samples of symptomatic children (11.4% and 5.2%), (6.9% and 2.9%), (13.9% and 6.4%) and (4.5% and 2.3%), respectively. Candida albicans and Cryptococcus neoformans were detected in the examined water and morbid stool samples at (7.8% and 2.9%) and (1.6% and 0%), respectively. Additionally, the existence of parasites, including Entamoeba histolytica (5.7% and 4%), Giardia lamblia (9% and 1.7%) and Cryptosporidium oocysts (15.1% and 3.5%), was determined. Regarding Toxoplasma gondii, sporulated oocysts were detected in the ground water (2.9%). The prevalence of diarrhea among the examined children in Abulnomorous was higher (24.7%) than those

  1. Critical body residues, Michaelis-Menten analysis of bioaccumulation, lethality and behaviour as endpoints of waterborne Ni toxicity in two teleosts.

    Science.gov (United States)

    Leonard, Erin M; Marentette, Julie R; Balshine, Sigal; Wood, Chris M

    2014-03-01

    Traditionally, water quality guidelines/criteria are based on lethality tests where results are expressed as a function of waterborne concentrations (e.g. LC50). However, there is growing interest in the use of uptake and binding relationships, such as biotic ligand models (BLM), and in bioaccumulation parameters, such as critical body residue values (e.g. CBR50), to predict metal toxicity in aquatic organisms. Nevertheless, all these approaches only protect species against physiological death (e.g. mortality, failed recruitment), and do not consider ecological death which can occur at much lower concentrations when the animal cannot perform normal behaviours essential for survival. Therefore, we investigated acute (96 h) Ni toxicity in two freshwater fish species, the round goby (Neogobius melanostomus) and rainbow trout (Oncorhynchus mykiss) and compared LC, BLM, and CBR parameters for various organs, as well as behavioural responses (spontaneous activity). In general, round goby were more sensitive. Ni bioaccumulation displayed Michaelis-Menten kinetics in most tissues, and round goby gills had lower Kd (higher binding affinity) but similar Bmax (binding site density) values relative to rainbow trout gills. Round goby also accumulated more Ni than did trout in most tissues at a given exposure concentration. Organ-specific 96 h acute CBR values tended to be higher in round goby but 96 h acute CBR50 and CBR10 values in the gills were very similar in the two species. In contrast, LC50 and LC10 values were significantly higher in rainbow trout. With respect to BLM parameters, gill log KNiBL values for bioaccumulation were higher by 0.4-0.8 log units than the log KNiBL values for toxicity in both species, and both values were higher in goby (more sensitive). Round goby were also more sensitive with respect to the behavioural response, exhibiting a significant decline of 63-75 % in movements per minute at Ni concentrations at and above only 8 % of the LC50 value

  2. Application of encapsulated aluminum pigments to waterborne coating%包覆型铝粉颜料在水性涂料中的应用

    Institute of Scientific and Technical Information of China (English)

    陈军; 皮丕辉; 蔡智奇; 文秀芳; 程江; 杨卓如

    2011-01-01

    以正硅酸乙酯(TEOS)和乙烯基三乙氧基硅烷(VTES)为前驱物,通过溶胶-凝胶反应在铝颜料表面形成了一层致密的包覆层,再通过甲基丙烯酸甲酯(MMA)和丙烯酸(AA)的自由基聚合反应对铝颜料进行第二层包覆,制备了含亲水基团的包覆型铝粉颜料,以此包覆的铝颜料配制了水性铝粉涂料.研究了铝粉及交联剂的用量、涂料黏度和烘烤温度对漆膜外观和性能的影响,获得了较佳的工艺条件如下:铝粉用量为3%,交联剂的用量为树脂用量的30%,涂料黏度为13 s,烘烤温度为150℃.以此工艺获得的水性铝粉涂料涂膜具有较佳的综合性能,光泽度达到73.4°.%An encapsulated aluminum pigment containing hydrophilic-group was prepared by producing dense encapsulation layer on the surface of aluminum pigment,which is formed with tetraethoxysilane (TEOS) and vinyltriethoxysilane (VTES) as precursors by sol-gel reaction,and by encapsulating the second layer formed by free radical copolymerization reaction of methyl methacrylate (MMA)and acrylic acid (AA). A waterborne aluminum coating was prepared with the encapsulated aluminum pigment. The effects of the amounts of aluminum pigment and crosslinking agent, viscosity of the coating material and baking temperature on film appearance and performance were studied. Good process conditions were obtained as follows:amount of aluminum pigment 3%, amount of crosslinking agent 30% compared with resin, viscosity 13 s, and baking temperature 150 ℃. The film of waterborne aluminum powder coating obtained from this process has excellent comprehensive performance and its luster is up to 73.4°.

  3. Identification of apoptosis-related genes Bcl2 and Bax from yellow catfish Pelteobagrus fulvidraco and their transcriptional responses to waterborne and dietborne zinc exposure.

    Science.gov (United States)

    Li, Dan-Dan; Luo, Zhi; Chen, Guang-Hui; Song, Yu-Feng; Wei, Chuan-Chuan; Pan, Ya-Xiong

    2017-10-30

    Apoptosis plays a key role in the physiology of multicellular organisms, and has been well studied in mammals, but not in teleosts. Zinc (Zn) has been shown to be an important regulator of apoptosis and apoptosis involves in the regulation of lipid metabolism. Moreover, our recent study indicated that waterborne and dietborne Zn exposure differently influenced lipid metabolism in Pelteobagrus fulvidraco, but further mechanism remained unknown. The hypothesis of the present study is that apoptosis mediated the Zn-induced changes of lipid metabolism of P. fulvidraco subjected to different exposure pathways. To this end, we cloned full-length cDNA sequences of Bcl2 and three Bax subtypes involved in apoptosis in P. fulvidraco, explored their mRNA expressions in responses to different Zn exposure pathways. Bcl2 and three Bax subtypes shared similar domain structure as typical pro- and anti-apoptotic Bcl2 family members. Their mRNAs were widely expressed among various tissues, but at variable levels. Waterborne Zn exposure down-regulated mRNA levels of Baxg and ratios of Baxa/Bcl2, and Baxg/Bcl2, but showed no significant effects on mRNA abundances of Bcl2, Baxa and Baxb, and the ratio of Baxb/Bcl2. In contrast, dietborne Zn exposure up-regulated mRNA levels of Bcl2, Baxa, Baxb and Baxg, but reduced the ratios of Baxa/Bcl2, Baxb/Bcl2, and Baxg/Bcl2. Considering their important roles of these genes in apoptosis induced by Zn, apoptosis may mediate the Zn-induced changes of hepatic lipid metabolism of Pelteobagrus fulvidraco under different Zn exposure pathways. For the first time, we characterized the full-length cDNA sequences of Bcl2 and three Bax subtypes, determined their expression profiles and transcriptional responses to different Zn exposure pathways, which would contribute to our understanding of the molecular basis of apoptosis, and also provide new insights into physiological responses to different Zn exposure pathways. Copyright © 2017 Elsevier B.V. All

  4. 水性聚氨酯/丙烯酸酯贴合料的制备%Preparation of Waterborne Polyurethane/Acrylate Adhesives

    Institute of Scientific and Technical Information of China (English)

    张利君; 李晓飞; 曾宪旦; 何时川; 吕建平

    2013-01-01

    In this study, castor oil (C.O) cross - linked waterborne polyurethanes ( WPU) with terminated hydrazine were synthesized using various combinations of N - 56, TDI, DMPA and ADH. And acrylates ( PA) with terminated ketone carbonyl was prepared by emulsion polymerization using butyl acrylate, methyl methacrylate and diacetone acrylamide monomers. Then, waterborne polyurethane/acrylate (WPUA) based adhesives were obtained by mixing WPU with PA in a proper weight ratio, which showed high cohesive strength as PVC leather binder. Influences ofn(C. 0) :n( N - 56) and n( C = 0):n(-NHNH2) on WPUA physical properties and related peel strength were also investigated. Results show that when n(C. O) :n(N -56) is 3/7 and n(C = 0) :n(-NHNH2) is 1.5 ~2, WPUA dispersion could get satisfied emulsion stability and good water - resistant. T -peel strength of the leather binder reaches 19. 6N/25mm, and still keeps 16. 6N/25mm after immersed in water for 24 hours.%以聚酯二元醇(N-56)、甲苯二异氰酸酯(TDI)、二羟甲基丙酸(DMPA)、己二酸二酰肼等为主要原料,蓖麻油(C.O)为交联剂,制备了肼基封端聚氨酯(WPU).以丙烯酸丁酯、甲基丙烯酸甲酯、双丙酮丙烯酰胺单体通过乳液聚合,合成了带有酮羰基的丙烯酸酯(PA),并同WPU按一定的质量比例混合制得水性聚氨酯/丙烯酸酯贴合料.考察了n(C.O) /n(N-56)、n(C =0) /n(-NHNH2)对WPUA性能以及剥离强度的影响.结果表明:当n(C.O)/n(N-56)为3/7、n(C =O) /n(-NHNH2)为1.5 ~2.0时,WPUA乳液稳定性和耐水性较好,皮革T-剥离强度可达到19.6N/25mm,泡水24h后为16.6N/25 mm.

  5. HDI三聚体改性磺酸盐型高固含量水性聚氨酯的制备与性能研究%Synthesis and Properties of High Solid Content Sulphonated Waterborne Polyurethane Modified by HDI Trimer

    Institute of Scientific and Technical Information of China (English)

    孙雪娇; 夏正斌; 李伟; 曹高华; 张燕红; 李忠

    2013-01-01

    Sulphonated waterborne polyurethane emulsions with 50% solid-content were successfully synthesized by using poly(1,4-butanediol adipate)diol (PBA), isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI) as the main raw materials, N-(2-aminoethyl)-amino ethane sulphonated sodium as hydrophilic chain extender, and HDI trimer (HT) as a modifier. The effects of the feeding method and the amount of HDI trimer on the latex particle size and distribution, Zeta potential and viscosity of waterborne polyurethane emulsions, and the water resistance, crystallinity and mechanical properties of the cast films of synthesized polyurethane were studied respectively by Malvern laser particle size analyzer, Brookfield viscometer, universal tensile machine, Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H-NMR), X-ray diffraction analysis (XRD), differential scanning calorimetry analysis (DSC) and transmission electron microscopy (TEM). The results show that, with the increase of the amount of HDI trimer, the viscosity of waterborne polyurethane emulsion decreases, the average particle size and its distribution of latex particles increase, and the tensile strength and elongation at break of the cast films are increased firstly and then decreased. The introduction of the HDI trimer into the polyurethane chain destroys the arrangement regularity of the polyurethane soft segment, which results in a slightly lower film crystallinity. When the ratio of HDI trimer to IPDI is 1:3 (mass ratio), the synthesized polyurethane shows excellent performance, which has the emulsion particle size of 199.3 nm, Zeta potential of-42.7 mV, the film water absorption of 3.8%and the film relative crystallinity of 50.62%.%  以异氟尔酮二异氰酸酯(IPDI)、六亚甲基二异氰酸酯(HDI)、聚己二酸1,4-丁二醇酯二醇(PBA)为主要原料,以乙二胺基乙磺酸钠(AAS)为亲水性扩链剂,以HDI三聚体(HT)为改性剂,制得了固含量

  6. Violation of Particle Anti-particle Symmetry

    CERN Document Server

    CERN. Geneva

    2001-01-01

    Symmetry is a fundamental concept which can be found in the whole range of human activities e. g. from arts to science. The beauty of a statues is often related to its symmetric form. In physics, all the laws are related to some sort of symmetry. Equally important is a small breakdown ofsymmetry. Even for the case of a statue, its beauty might be enhanced by introducing small distortions. In this course, we investigate the role symmetry in the world of elementary particles. Some symmetries found there are very similar to those which can be seen in our daily life, while others are more exotic and related to the quantum nature of the elementary particles. Our particular focus ismade on symmetry and its violation between the matter and anti-matter, known as CP violation. It is experimentally well established that particleand anti-particle behave a tiny bit differently in the world of elementary particles. We discuss how this would be explained and how we can extendour knowledge. Evolution of our universe is stro...

  7. Particle Swarm Optimisation with Spatial Particle Extension

    DEFF Research Database (Denmark)

    Krink, Thiemo; Vesterstrøm, Jakob Svaneborg; Riget, Jacques

    2002-01-01

    In this paper, we introduce spatial extension to particles in the PSO model in order to overcome premature convergence in iterative optimisation. The standard PSO and the new model (SEPSO) are compared w.r.t. performance on well-studied benchmark problems. We show that the SEPSO indeed managed...

  8. Teaching German Modal Particles.

    Science.gov (United States)

    Rosler, Dietmar

    1982-01-01

    Believes modern linguistics has done little to explore German modal particles because by focusing on sentences as the basic category for linguistic thinking these words did not seem to matter. Describes model which gives students experience with these particles in meaningful communication. (Author/BK)

  9. Solar Energetic Particles

    Science.gov (United States)

    Király, Péter

    Energetic particles recorded in the Earth environment and in interplanetary space have a multitude of origins, i.e. acceleration and propagation histories. At early days practically all sufficiently energetic particles were considered to have come either from solar flares or from interstellar space. Later on, co-rotating interplanetary shocks, the termination shock of the supersonic solar wind, planetary bow shocks and magnetospheres, and also coronal mass ejections (CME) were recognized as energetic particle sources. It was also recognized that less energetic (suprathermal) particles of solar origin and pick-up ions have also a vital role in giving rise to energetic particles in interplanetary disturbances. The meaning of the term "solar energetic particles" (SEP) is now somewhat vague, but essentially it refers to particles produced in disturbances fairly directly related to solar processes. Variation of intensity fluctuations with energy and with the phase of the solar cycle will be discussed. Particular attention will be given to extremes of time variation, i.e. to very quiet periods and to large events. While quiet-time fluxes are expected to shed light on some basic coronal processes, large events dominate the fluctuation characteristics of cumulated fluence, and the change of that fluctuation with energy and with the phase of the solar cycle may also provide important clues. Mainly ISEE-3 and long-term IMP-8 data will be invoked. Energetic and suprathermal particles that may never escape into interplanetary space may play an important part in heating the corona of the sun.

  10. Particle Physics Instrumentation

    OpenAIRE

    Riegler, Werner

    2014-01-01

    This report summarizes a series of three lectures aimed at giving an overview of basic particle detection principles, the interaction of particles with matter, the application of these principles in modern detector systems, as well techniques to read out detector signals in high-rate experiments.

  11. RESEARCH IN PARTICLE PHYSICS

    Energy Technology Data Exchange (ETDEWEB)

    Kearns, Edward [Boston Universiy

    2013-07-12

    This is the final report for the Department of Energy Grant to Principal Investigators in Experimental and Theoretical Particle Physics at Boston University. The research performed was in the Energy Frontier at the LHC, the Intensity Frontier at Super-Kamiokande and T2K, the Cosmic Frontier and detector R&D in dark matter detector development, and in particle theory.

  12. Particles, contacts, bulk behavior

    NARCIS (Netherlands)

    Luding, Stefan; Tomas, J.

    2014-01-01

    Granular matter consists of discrete “particles”. These can be separate sand-grains, agglomerates (made of many primary particles), or solid materials like rock, composites, or metal-alloys—all with particulate inhomogeneous, possibly anisotropic micro-structure. Particles can be as small as

  13. Teaching particle physics

    CERN Document Server

    Hanley, P

    2000-01-01

    Particle physics attracts many students who hear of news from CERN or elsewhere in the media. This article examines which current A-level syllabuses include which bits of particle physics and surveys the many different types of resource available to teachers and students. (0 refs).

  14. Ice particle collisions

    Science.gov (United States)

    Sampara, Naresh; Turnbull, Barbara; Hill, Richard; Swift, Michael

    2017-04-01

    Granular interactions of ice occur in a range of geophysical, astrophysical and industrial applications. For example, Saturn's Rings are composed of icy particles from micrometers to kilometres in size - inertial and yet too small to interact gravitationally. In clouds, ice crystals are smashed to pieces before they re-aggregate to for snow floccules in a process that is very much open to interpretation. In a granular flow of ice particles, the energy spent in collisions can lead to localized surface changes and wetting, which in turn can promote aggregation. To understand the induced wetting and its effects, we present two novel experimental methods which provide snippets of insight into the collisional behaviour of macroscopic ice particles. Experiment 1: Microgravity experiments provide minute details of the contact between the ice particles during the collision. A diamagnetic levitation technique, as alternative to the parabolic flight or falling tower experiments, was used to understand the collisional behaviour of individual macroscopic icy bodies. A refrigerated cylinder, that can control ambient conditions, was inserted into the bore of an 18 Tesla superconducting magnet and cooled to -10°C. Initial binary collisions were created, where one 4 mm ice particle was levitated in the magnet bore whilst another particle was dropped vertically from the top of the bore. The trajectories of both particles were captured by high speed video to provide the three-dimensional particle velocities and track the collision outcome. Introducing complexity, multiple particles were levitated in the bore and an azimuthal turbulent air flow introduced, allowing the particles to collide with other particles within a coherent fluid structure (mimicking Saturn's rings, or an eddy in a cloud). In these experiments, a sequence of collisions occur, each one different to the previous one due to the changes in surface characteristics created by the collisions themselves. Aggregation

  15. DEM Particle Fracture Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Boning [Univ. of Colorado, Boulder, CO (United States); Herbold, Eric B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Homel, Michael A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Regueiro, Richard A. [Univ. of Colorado, Boulder, CO (United States)

    2015-12-01

    An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density and packings o the samples are also studied in numerical examples.

  16. HIGH ENERGY PARTICLE ACCELERATOR

    Science.gov (United States)

    Courant, E.D.; Livingston, M.S.; Snyder, H.S.

    1959-04-14

    An improved apparatus is presented for focusing charged particles in an accelerator. In essence, the invention includes means for establishing a magnetic field in discrete sectors along the path of moving charged particles, the magnetic field varying in each sector in accordance with the relation. B = B/ sub 0/ STAln (r-r/sub 0/)/r/sub 0/!, where B/sub 0/ is the value of the magnetic field at the equilibrium orbit of radius r/sub 0/ of the path of the particles, B equals the magnetic field at the radius r of the chamber and n equals the magnetic field gradient index, the polarity of n being abruptly reversed a plurality of times as the particles travel along their arcuate path. With this arrangement, the particles are alternately converged towards the axis of their equillbrium orbit and diverged therefrom in successive sectors with a resultant focusing effect.

  17. Compact particle accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Elizondo-Decanini, Juan M.

    2017-08-29

    A compact particle accelerator having an input portion configured to receive power to produce particles for acceleration, where the input portion includes a switch, is provided. In a general embodiment, a vacuum tube receives particles produced from the input portion at a first end, and a plurality of wafer stacks are positioned serially along the vacuum tube. Each of the plurality of wafer stacks include a dielectric and metal-oxide pair, wherein each of the plurality of wafer stacks further accelerate the particles in the vacuum tube. A beam shaper coupled to a second end of the vacuum tube shapes the particles accelerated by the plurality of wafer stacks into a beam and an output portion outputs the beam.

  18. 水性聚氨酯性能的影响因素研究%Study on Factors Influencing the Performance of Waterborne Polyurethane

    Institute of Scientific and Technical Information of China (English)

    王安民

    2009-01-01

    Series of waterborne polyurethane dispersion and film therefrom are prepared under different conditions with poly (tetramethylene oxide) (PTMG-1000), isophorone diisocyanate (IPDI) and TDI as main materials, dimethylol propionic acid (DMPA) as hydrophilic chain extender, 1,4-butanediol (BDO) and ethylenediamine (EA) as micromolecular chain extender. The effects of molecular structure and dispersion conditions on the stability of emulsion and properties of emulsion film are analyzed by studying the hardness, water absorption, adhesion and etc. of the emulsion film.%以聚四氢呋喃二醇(PTMG-1000)、异佛尔酮二异氰酸酯(IPDI)、甲苯2,4-二异氰酸酯(TDI)为主要原料,二羟甲基丙酸(DMPA)为亲水性扩链剂,1,4-丁二醇(BDO)和乙二胺(EA)为小分子扩链剂,在不同条件下制备了系列水性聚氨酯分散体并制备胶膜.通过对胶膜硬度、吸水率以及附着力等的研究,分析分子结构及分散条件对乳液稳定性和胶膜性能的影响.

  19. Study on the Preparation Technique of Waterborne Polyurethane Dispersion%水性聚氨酯分散体制备技术的研究

    Institute of Scientific and Technical Information of China (English)

    孙道兴; 崔琳

    2012-01-01

    The series of waterborne polyurethane dispersion were prepared in different conditions by use of IPDI, TDI, polycarbonate diol ( L5652-2000 )and polytetrahydrofuran glycol ( PTMG-2000 )as main materials, dimethylol propionic acid as hydrophilic monomer, and 1, 4-butanediol (BDO)and ethanediamine as chain extender. The influences of molecular structure and dispersing condition on the dispersion stability and film performance were analyzed by the study of hardness, water absorption and adhesion of films.%以异佛尔酮二异氰酸酯(IPDI)、甲苯-2,4-二异氰酸酯(TDI)、聚碳酸酯二醇(L5652—2000)和聚四氢呋喃二醇(PTMG-2000)为主要原料,2,2-二羟甲基丙酸(DMPA)为亲水单体,1,4-丁二醇(BDO)和乙二胺(EA)为扩链剂,在不同条件下制备了系列水性聚氨酯分散体。通过对胶膜硬度、吸水率以及附着力等的研究,分析了分子结构及分散条件对分散体稳定性和胶膜性能的影响。

  20. 水性膨胀型隧道防火防霉涂料%Waterborne Expansion Type Fire Resisting & Mildewproof Coatings for Tunnel

    Institute of Scientific and Technical Information of China (English)

    刘成楼; 唐国军

    2012-01-01

    Waterborne coatings for tunnel was prepared by using silicone acrylic emulsion as binder; modified ammonium polyphosphate, melamine, dipentaerythritol, azodicarbonamide as flame retardant; titanium dioxide, zinc borate, expandable graphite as extender and nano SiO2 as modifier; assisted with the negative ion antimicrobial additives and a variety of additives. The coatings with excellent properties sueh as flame resisting, strong adhesion, anti-mildew antibacterial, impermeability of waterproof, nontoxic, good decoration and construction conveniently.%以硅丙乳液为基料,以改性聚磷酸铵、三聚氰胺、双季戊四醇、偶氮二甲酰胺为阻燃剂,以钛白粉、硼酸锌、可膨胀石墨为填料,以纳米SiO2为改性剂,在负离子抗茵添加剂和多种助剂配合下,制备的水性隧道防火涂料,具有防火性好、黏附性强、防霉抗菌、防水抗渗、环保无毒、装饰性好、施工方便等特点。

  1. Hospitalization records as a tool for evaluating performance of food- and water-borne disease surveillance systems: a Massachusetts case study.

    Directory of Open Access Journals (Sweden)

    Siobhan M Mor

    Full Text Available We outline a framework for evaluating food- and water-borne surveillance systems using hospitalization records, and demonstrate the approach using data on salmonellosis, campylobacteriosis and giardiasis in persons aged ≥65 years in Massachusetts. For each infection, and for each reporting jurisdiction, we generated smoothed standardized morbidity ratios (SMR and surveillance to hospitalization ratios (SHR by comparing observed surveillance counts with expected values or the number of hospitalized cases, respectively. We examined the spatial distribution of SHR and related this to the mean for the entire state. Through this approach municipalities that deviated from the typical experience were identified and suspected of under-reporting. Regression analysis revealed that SHR was a significant predictor of SMR, after adjusting for population age-structure. This confirms that the spatial "signal" depicted by surveillance is in part influenced by inconsistent testing and reporting practices since municipalities that reported fewer cases relative to the number of hospitalizations had a lower relative risk (as estimated by SMR. Periodic assessment of SHR has potential in assessing the performance of surveillance systems.

  2. Testing for the induction of anti-herbivory defences in four Portuguese macroalgae by direct and water-borne cues of grazing amphipods

    Science.gov (United States)

    Yun, Hee Young; Cruz, Joana; Treitschke, Michaela; Wahl, Martin; Molis, Markus

    2007-09-01

    Herbivory is a key factor in regulating plant biomass, thereby driving ecosystem performance. Algae have developed multiple adaptations to cope with grazers, including morphological and chemical defences. In a series of experiments we investigated whether several species of macroalgae possess anti-herbivore defences and whether these could be regulated to demand, i.e. grazing events. The potential of direct grazing on defence induction was assessed for two brown ( Dictyopteris membranacea, Fucus vesiculosus) and two red seaweeds ( Gelidium sesquipedale, Sphaerococcus coronopifolius) from São Rafael and Ria Formosa, Portugal. Bioassays conducted with live algal pieces and agar-based food containing lipophilic algal extracts were used to detect changes in palatability after exposure to amphipod attacks (=treatment phase). Fucus vesiculosus was the only species significantly reducing palatability in response to direct amphipod-attacks. This pattern was observed in live F. vesiculosus pieces and agar-based food containing a lipophilic extract, suggesting that lipophilic compounds produced during the treatment phase were responsible for the repulsion of grazers. Water-borne cues of grazed F. vesiculosus as well as non-grazing amphipods also reduced palatability of neighbouring conspecifics. However, this effect was only observed in live tissues of F. vesiculosus. This study is the first to show that amphipods, like isopods, are capable to induce anti-herbivory defences in F. vesiculosus and that a seasonally variable effectiveness of chemical defences might serve as a dynamic control in alga-herbivore interactions.

  3. 水性丙烯酸铝粉浸涂漆的研究%Study on Waterborne Acrylic Resin Aluminium Dipping Paint

    Institute of Scientific and Technical Information of China (English)

    李秀苗; 董红专

    2001-01-01

    A waterborne aluminium dipping paint has been prepared based on non- water soluble melamine - alkyd resin as grafting precursor, diluted with water- soluble organic solvents,then graft polymerized with acrylic monomers and styrene, mixedwith special aluminium pigment and additives. The influences of types of melamine resins, initiators and additives on film properties are discussed. Application guides are also given.%以非水溶性氨基树脂为接枝聚合母体,先将其用水溶性有机溶剂配成稀溶液,然后加入丙烯酸单体及苯乙烯混合物进行接枝聚合,所得的树脂中加入特种铝粉及各种助剂,配制成水性铝粉浸涂漆。讨论了氨基树脂类型、引发剂、助剂等对漆膜性能的影响,并介绍了施工注意事项。

  4. Development of Waterborne Wiping - Type Colorant for Wooden Products%水性木器擦涂着色剂的研制及其应用

    Institute of Scientific and Technical Information of China (English)

    唐述华; 许美琪

    2012-01-01

    在充分比较各种着色剂的基础上,研制出新型水性木材擦涂着色剂,讨论分析了着色剂中色粉、体质颜料、各种助剂及分散介质水等各种成分的特点、组成以及制作工艺.特别是为了减少色差和适应DIY室内涂饰需求,将色粉按所需木材色泽要求量加入,同时配方中还引入了延时干燥物质,延长了可擦涂时间,适应了大面积和工厂化生产的需求.%Based on scrutinous analysis of properties of various colorants,a novel waterborne swabbing colorant for wood is prepared. Various components of the colorant,i. e. toners,bulk pigments,additives and dispersing medium,their characteristics and compositions ads well as preparing process are discussed. The volume of toner incorporated into the colorant formula is determined as required by wood color,which is especially designed for reduction of color difference and for workability of indoor DIY decoration. In addition ,a dry - delaying agent is incorporated into formula to prolong swabbing time with the purpose of being applicable to larger scale field or factory applications.

  5. The water-borne protein signals (pheromones) of the Antarctic ciliated protozoan Euplotes nobilii: structure of the gene coding for the En-6 pheromone.

    Science.gov (United States)

    La Terza, Antonietta; Dobri, Nicoleta; Alimenti, Claudio; Vallesi, Adriana; Luporini, Pierangelo

    2009-01-01

    The marine Antarctic ciliate, Euplotes nobilii, secretes a family of water-borne signal proteins, denoted as pheromones, which control vegetative proliferation and mating in the cell. Based on the knowledge of the amino acid sequences of a set of these pheromones isolated from the culture supernatant of wild-type strains, we designed probes to identify their encoding genes in the cell somatic nucleus (macronucleus). The full-length gene of the pheromone En-6 was determined and found to contain an open-reading frame specific for the synthesis of the En-6 cytoplasmic precursor (pre-pro-En-6), which requires 2 proteolytic cleavages to remove the signal peptide (pre) and the prosegment before secretion of the mature protein. In contrast to the sequence variability that distinguishes the secreted pheromones, the pre- and pro-sequences appear to be tightly conserved and useful for the construction of probes to clone every other E. nobilii pheromone gene. Potential intron sequences in the coding region of the En-6 gene imply the synthesis of more En-6 isoforms.

  6. Development of a combined in vitro cell culture--quantitative PCR assay for evaluating the disinfection performance of pulsed light for treating the waterborne enteroparasite Giardia lamblia.

    Science.gov (United States)

    Garvey, Mary; Stocca, Alessia; Rowan, Neil

    2014-09-01

    Giardia lamblia is a flagellated protozoan parasite that is recognised as a frequent cause of water-borne disease in humans and animals. We report for the first time on the use of a combined in vitro HCT-8 cell culture-quantitative PCR assay for evaluating the efficacy of using pulsed UV light for treating G. lamblia parasites. Findings showed that current methods that are limited to using vital stains before and after cyst excystation are not appropriate for monitoring or evaluating cyst destruction post PUV-treatments. Use of the human ileocecal HCT-8 cell line was superior to that of the human colon Caco-2 cell line for in vitro culture and determining PUV sensitivity of treated cysts. G. lamblia cysts were also shown to be more resistant to PUV irradiation compared to treating similar numbers of Cryptosporidium parvum oocysts. These observations also show that the use of this HCT-8 cell culture assay may replace use of animal models for determining disinfection performances of PUV for treating both C. parvum and G. lamblia.

  7. Effect of ingestion and waterborne routes under different shrimp densities on white spot syndrome virus susceptibility in three commercially important penaeid shrimps

    Directory of Open Access Journals (Sweden)

    Kuzhanthaivel Raja

    2015-11-01

    Full Text Available A study was undertaken to evaluate some factors that are important for better management of the white spot syndrome virus (WSSV. We examined the likelihood of that the mud crab (Scylla serrata is a potential carrier of WSSV in shrimp farms and then compared susceptibility of three shrimp species to WSSV, and finally tested the effects of shrimp stocking density and transmission routes on the intensity of WSSV infection under experimental conditions. Mud crabs were collected from the crab fattening unit of Pichavaram mangroves area, southeast coast of India. The infectivity test was conducted on Penaeus monodon, P. indicus, Litopenaeus vannamei under three different shrimp densities and two different routes of infection. Each treatment was executed in triplicate of 100 L tanks. The results showed that S. serrata is a carrier of WSSV. Among three species of shrimps, P. indicus was most susceptible and L. vannamei was most resistant in term of cumulative mortality. Ingestion route was more effective than waterborne route on WSSV outbreaks. Cumulative mortality of shrimps due to WSSV infection increased with increasing shrimp density. The result of this study is important to improve management especially to minimize the WSSV infection in the shrimp farms.

  8. 金属用水性隔热防腐涂料的研制%Study on Waterborne Heat-Insulating and Anti-Corrosive Coatings for Metal

    Institute of Scientific and Technical Information of China (English)

    刘成楼; 唐国军

    2012-01-01

    以防锈专用苯丙乳液为基料,以钛白粉、热反射粉、磷酸铝锌、空心玻璃微珠为颜填料,以纳米SiO2为改性材料,制备了水性隔热防腐涂料,当PVC(颜料体积浓度)为25%时,涂料具有底面合一、太阳光反射隔热、防锈防腐、绿色环保、耐候耐久、装饰性好等特点。%A waterborne heat-insu acrylic emulsion as hinder, titanium lating dioxid as pigments and fillers, and nano-SiO2 reflective insulation, rust and corrosion etc. features when PVC was 25%. and anti-corrosive coatings was prepared by special antirust styrene- e, heat-reflective powder, aluminum zinc phosphate, hollow glass beads as modified material. The coatings can be used as one coat paint. It had resistance, environmental-friendly, weather resistance, good decorative

  9. Effect of covalent modification of graphene nanosheets on the electrical property and electromagnetic interference shielding performance of a water-borne polyurethane composite.

    Science.gov (United States)

    Hsiao, Sheng-Tsung; Ma, Chen-Chi M; Tien, Hsi-Wen; Liao, Wei-Hao; Wang, Yu-Sheng; Li, Shin-Ming; Yang, Chih-Yu; Lin, Sheng-Chi; Yang, Ruey-Bin

    2015-02-04

    Flexible and lightweight graphene nanosheet (GN)/waterborne polyurethane (WPU) composites which exhibit high electrical conductivity and electromagnetic shielding performance were prepared. Covalently modifying GNs with aminoethyl methacrylate (AEMA; AEMA-GNs) through free radical polymerization effectively inhibited the restacking and aggregation of the GNs because of the -NH3(+) functional groups grafted on the AEMA-GNs. Moreover, the AEMA-GNs exhibited high compatibility with a WPU matrix with grafted sulfonated functional groups because of the electrostatic attraction, which caused the AEMA-GNs to homogeneously disperse in the WPU matrix. This homogeneous distribution enabled the GNs to form electrically conductive networks. Furthermore, AEMA-GNs with different amounts of AEMA segments were introduced into the WPU matrix, and the effects of the surface chemistry of the GNs on the electrical conductivity and EMI shielding performance of composites were investigated. AEMA-GN/WPU composites with a GN loading of 5 vol % exhibited remarkable electrical conductivity (approximately 43.64 S/m) and EMI shielding effectiveness (38 dB) over the frequency of 8.2 to 12.4 GHz.

  10. Research on Graphene Oxide Modified Waterborne Polyurethane Leather Finishing%水性聚氨酯/氧化石墨烯皮革涂饰剂的研究

    Institute of Scientific and Technical Information of China (English)

    贾春茂; 吕生华; 丁怀东

    2016-01-01

    The waterborne polyurethane (WPU)/grapheme oxide (GO) complex leather finishing agents were prepared by mixing WPU and GO under ultrasonic treatment. The dispersion degree of GO nanosheets in WPU was improved by added the sodium dodecyl sulfate (SDS), and effects of content of SDS and GO on the performance of WPU/GO were investigated. The applied results indicated that adding SDS can improve the dispersion degree of GO nanosheets in WPU. The composite coating have excellent water resistance, wet-dry rubbing fastenss and surface gloss as well as high tensile strength.%采用溶液共混法制备了水性聚氨酯(WPU)/氧化石墨烯(GO)复合皮革涂饰剂,研究了讨论了SDS和GO掺量对水性聚氨酯性能的影响。实验结果表明SDS的引入提高了GO在WPU中的分散均匀性,WPU/GO复合皮革涂饰剂应用试验结果表明涂层的抗水性、耐干湿擦性能显著的提高,表面光泽度好,涂层强度也有明显的提高。

  11. 水性工业隔热涂料的研制与应用%Preparation and Use of Water-borne Industrial Thermal Insulating Coating

    Institute of Scientific and Technical Information of China (English)

    刘成楼; 唐国军

    2012-01-01

    介绍了水性工业隔热涂料的配方、工艺、应用方法,通过试验确定了以有机硅乳液和丙烯酸乳液混配作胶黏剂,以空心玻璃微珠为主、配合膨胀蛭石、玻化微珠、无机纤维、硅藻土等为隔热填料,颜基比为6∶4。在输热管道上涂覆隔热涂层3 mm,在管内温度200℃条件下,隔热温差达45℃,节能15%左右。%This paper introduces the compositions, technology and application method of water-borne industrial thermal insulation coatings. It is determined that with silicone emulsion and acrylic emulsion as mixing binders, with hollow glass beads as main insulation filler together with expanded vermiculite, glass micro-beads, inorganic fibers and diatomite, under the pigment and binder ratio of 6 : 4, and coating 3 mm on the heat supply pipeline, the effect of thermal insulation can be gotten: the temperature difference reaching 45 ℃ and energy saving reaching 15%.

  12. P-glycoprotein and CYP1A protein expression patterns in Nile tilapia (Oreochromis niloticus) tissues after waterborne exposure to benzo(a)pyrene (BaP).

    Science.gov (United States)

    Costa, Joana; Reis-Henriques, Maria Armanda; Wilson, Jonathan M; Ferreira, Marta

    2013-09-01

    The protein levels and tissue distribution patterns of P-glycoprotein (Pgp) and cytochrome P450 (CYP1A) were investigated in Nile tilapia (Oreochromis niloticus) after waterborne exposure to different benzo(a)pyrene (BaP) concentrations, using immunochemical approaches. The Pgp mammalian monoclonal antibody (mAb) C219 cross reacted with a ∼170kDa protein, almost exclusively localized to the bile canaliculi, while probing with the Pgp mammalian mAb C494, resulted in a positive reaction in liver, gills and intestine of Nile tilapia and covered a wider set of cell types. Levels of Pgp expression were not altered after in vivo exposure to BaP. CYP1A, detected with the mAb C10-7, reacted positively in liver, gills and intestine and followed a BaP dose-dependent fold induction. Taken together, these results indicate that CYP1A is involved in BaP metabolism in liver, gills and intestine, however, further studies are needed to elucidate the possible interaction of the efflux protein Pgp with BaP and/or its metabolites.

  13. Waterborne fluoride exposure changed the structure and the expressions of steroidogenic-related genes in gonads of adult zebrafish (Danio rerio).

    Science.gov (United States)

    Li, MeiYan; Cao, Jinling; Chen, Jianjie; Song, Jie; Zhou, Bingrui; Feng, Cuiping; Wang, Jundong

    2016-02-01

    Excessive fluoride in natural water ecosystem has been demonstrated to have adverse effects on reproductive system in humans and mammals, while the most vulnerable aquatic organisms were ignored. In this study, the effects of waterborne fluoride on growth performance, sex steroid hormone, histological structure, and the transcriptional profiles of sex steroid related genes were examined in both female and male zebrafish exposed to different concentrations of 0.79, 18.60, 36.83 mg L(-1) of fluoride for 30 and 60 d to investigate the effects of fluoride on reproductive system and the underlying toxic mechanisms caused by fluoride. The results showed that the body weight was remarkably decreased, the structure of ovary and testis were serious injured, and the T and E2 levels were significantly reduced in male zebrafish. The transcriptional profiles of steroidogenic related genes displayed phenomenal alterations, the expressions of pgr and cyp19a1a were significantly up-regulated, while the transcriptional levels of er, ar and hsd3β were decreased both in the ovary and testis, and hsd17β8 were down-regulated just in males. Taken together, these results demonstrated that fluoride could significantly inhibit the growth of zebrafish, and notably affect the reproductive system in both sex zebrafish by impairing the structure of ovary and testis, altering steroid hormone levels and steroidogenic genes expression related to the synthesis of sex hormones in zebrafish. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Comparison of different solar reactors for household disinfection of drinking water in developing countries: evaluation of their efficacy in relation to the waterborne enteropathogen Cryptosporidium parvum.

    Science.gov (United States)

    Gómez-Couso, H; Fontán-Sainz, M; Navntoft, C; Fernández-Ibáñez, P; Ares-Mazás, E

    2012-11-01

    Solar water disinfection (SODIS) is a type of treatment that can significantly improve the microbiological quality of drinking water at household level and therefore prevent waterborne diseases in developing countries. Cryptosporidium parvum is an obligate protozoan parasite responsible for the diarrhoeal disease cryptosporidiosis in humans and animals. Recently, this parasite has been selected by the WHO as a reference pathogen for protozoan parasites in the evaluation of household water treatment options. In this study, the field efficacy of different static solar reactors [1.5 l transparent plastic polyethylene terephthalate (PET) bottles as well as 2.5 l borosilicate glass and 25 l methacrylate reactors fitted with compound parabolic concentrators (CPC)] for solar disinfection of turbid waters experimentally contaminated with C. parvum oocysts was compared. Potential oocyst viability was determined by inclusion/exclusion of the fluorogenic vital dye propidium iodide. The results demonstrate that static solar reactors fitted with CPCs are an excellent alternative to the conventional SODIS method with PET bottles. These reactors improved the efficacy of the SODIS method by enabling larger volumes of water to be treated and, in some cases, the C. parvum oocysts were rendered totally unviable, minimising the negative effects of turbidity.

  15. Immunohistochemical analysis of cytochrome P4501A induction in organs and cell types of Rivulus marmoratus exposed to waterborne 2,3,7,8-tetrachlorodibenzo-p-dioxin

    Energy Technology Data Exchange (ETDEWEB)

    Stegeman, J.; Smolowitz, R.; Burnett, K.; DiBona, D. [Woods Hole Oceanographic Institution, Woods Hole, MA (United States)]|[Medical College of South Carolina, Charleston, SC (United States)

    1994-12-31

    Identifying target cells and organs is critical to establishing the sites and mechanisms of toxicity of Ah-receptor agonists. Previous studies have described the localization of CYPLA induced in multiple organs of fish exposed to Ah-receptor agonists. Here the authors compare the responses in multiple cell types and organs of small fish (Rivulus) exposed to waterborne TCDD. Adult fish were exposed to TCDD at concentrations from 0.01 to 10 ng/liter for 48 hours, then prepared and analyzed by immunohistochemistry with monoclonal antibody to teleost CYPIAI. At the highest dose profound induction was detected in virtually every organ. Structures staining intensely were: nasal and cephalic chemoreceptors, including sensory and basal cells; superficial cells in skin and pharynx; cartilage cells (chondrocytes) in the head, gills, growth plates and fins; epithelial and endothelial cells of liver, gut, kidney, and gill; pseudobranch vessels and glandular cells; eye lens epithelium; endothelium in vessels of eye, brain, skin, muscle, thymus and gonad. Lesser concentrations of TCDD elicited less strong responses, and control fish showed mild staining only in cartilage structures. The dose-dependent patterns of induction differed between different cell types. Responsive cells identified is these fish indicate sites where toxicity associated with Ah-receptor agonists or with CYPLA function may be expressed.

  16. Sex- and tissue-specific effects of waterborne estrogen on estrogen receptor subtypes and E2-mediated gene expression in the reproductive axis of goldfish.

    Science.gov (United States)

    Marlatt, Vicki L; Lakoff, Josh; Crump, Kate; Martyniuk, Chris J; Watt, Jennifer; Jewell, Linda; Atkinson, Susanna; Blais, Jules M; Sherry, Jim; Moon, Thomas W; Trudeau, Vance L

    2010-05-01

    This research examined the gene expression profile of three goldfish estrogen receptor (ER) subtypes in multiple tissues in relation to mRNA levels of aromatase B and vitellogenin (VTG) following waterborne estrogen exposures. The protocol consisted of: i) adult male goldfish in late gonadal recrudescence exposed to 1 nM 17beta-estradiol (E2); ii) adult male and female goldfish in early sexual regression exposed to 1 nM E2 for 3, 6, 12 and 24h; and, iii) sexually mature, adult male goldfish exposed to 0.3 nM 17alpha-ethynylestradiol (EE2) for 24h. Liver produced the most consistent response with up-regulation of ERalpha in sexually regressed, mature and recrudescing males and in sexually regressed females. The dose and length of exposure, reproductive state and sex affected the auto-regulation of ERbeta1 by E2. ERbeta2 was not affected in any experiments suggesting it may not be auto-regulated by E2. Aromatase B and VTG gene expression were affected by E2, but also by other experimental conditions. EE2 induced liver ERalpha and VTG mRNA levels indicating that high environmental EE2 levels induce E2-mediated gene expression in a model teleost. These studies reveal a more complicated action of estrogenic compounds that has important implications on estrogenic endocrine disruptors in teleosts. Copyright 2010 Elsevier Inc. All rights reserved.

  17. Untangling the Impacts of Climate Change on Waterborne Diseases: a Systematic Review of Relationships between Diarrheal Diseases and Temperature, Rainfall, Flooding, and Drought.

    Science.gov (United States)

    Levy, Karen; Woster, Andrew P; Goldstein, Rebecca S; Carlton, Elizabeth J

    2016-05-17

    Global climate change is expected to affect waterborne enteric diseases, yet to date there has been no comprehensive, systematic review of the epidemiological literature examining the relationship between meteorological conditions and diarrheal diseases. We searched PubMed, Embase, Web of Science, and the Cochrane Collection for studies describing the relationship between diarrheal diseases and four meteorological conditions that are expected to increase with climate change: ambient temperature, heavy rainfall, drought, and flooding. We synthesized key areas of agreement and evaluated the biological plausibility of these findings, drawing from a diverse, multidisciplinary evidence base. We identified 141 articles that met our inclusion criteria. Key areas of agreement include a positive association between ambient temperature and diarrheal diseases, with the exception of viral diarrhea and an increase in diarrheal disease following heavy rainfall and flooding events. Insufficient evidence was available to evaluate the effects of drought on diarrhea. There is evidence to support the biological plausibility of these associations, but publication bias is an ongoing concern. Future research evaluating whether interventions, such as improved water and sanitation access, modify risk would further our understanding of the potential impacts of climate change on diarrheal diseases and aid in the prioritization of adaptation measures.

  18. Plant extract-mediated biogenic synthesis of silver, manganese dioxide, silver-doped manganese dioxide nanoparticles and their antibacterial activity against food- and water-borne pathogens.

    Science.gov (United States)

    Krishnaraj, Chandran; Ji, Byoung-Jun; Harper, Stacey L; Yun, Soon-Il

    2016-05-01

    Silver nanoparticles (AgNPs), manganese dioxide nanoparticles (MnO₂NPs) and silver-doped manganese dioxide nanoparticles (Ag-doped MnO₂NPs) were synthesized by simultaneous green chemistry reduction approach. Aqueous extract from the leaves of medicinally important plant Cucurbita pepo was used as reducing and capping agents. Various characterization techniques were carried out to affirm the formation of nanoparticles. HR-TEM analysis confirmed the size of nanoparticles in the range of 15-70 nm and also metal doping was confirmed through XRD and EDS analyses. FT-IR analysis confirmed that the presence of biomolecules in the aqueous leaves extract was responsible for nanoparticles synthesis. Further, the concentration of metals and their doping in the reaction mixture was achieved by ICP-MS. The growth curve and well diffusion study of synthesized nanoparticles were performed against food- and water-borne Gram-positive and Gram-negative bacterial pathogens. The mode of interaction of nanoparticles on bacterial cells was demonstrated through Bio-TEM analysis. Interestingly, AgNPs and Ag-doped MnO₂NPs showed better antibacterial activity against all the tested bacterial pathogens; however, MnO₂NPs alone did not show any antibacterial properties. Hence, AgNPs and Ag-doped MnO₂NPs synthesized from aqueous plant leaves extract may have important role in controlling various food spoilage caused by bacteria.

  19. Apparatus for measuring particle properties

    Science.gov (United States)

    Rader, D.J.; Castaneda, J.N.; Grasser, T.W.; Brockmann, J.E.

    1998-08-11

    An apparatus is described for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle`s size can be determined from the intensity of the light scattered. The particle`s velocity can be determined from the elapsed time between various intensities of the light scattered. 11 figs.

  20. Particle physics builds potential

    CERN Document Server

    Camporesi, Tiziano

    2004-01-01

    Surveys of the career prospects of particle physicists in Europe, such as that one carried out in 2000 at DELPHI, reveal that particle phycisists are much in demand. The findings are fairly independent of a student's nationality, despite the big differences in the education systems of different countries across the continent. According to the DELPHI survey, half of all physics students remain in an academic environment after graduation. For those particle physicists who leave academia, the DELPHI survey showed that about half find jobs in hi- tech industry. The bottom line is that a degree in physics offers very good job prospects and career opportunities. (Edited abstract).