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Sample records for compositionally flexible aqueous

  1. Curing mechanism of flexible aqueous polymeric coatings.

    Irfan, Muhammad; Ahmed, Abid Riaz; Kolter, Karl; Bodmeier, Roland; Dashevskiy, Andriy

    2017-06-01

    The objective of this study was to explain curing phenomena for pellets coated with a flexible polymeric coating based on poly(vinyl acetate) (Kollicoat® SR 30D) with regard to the effect of starter cores, thickness of drug layer, adhesion of coating to drug-layered-cores as well as coating properties. In addition, appropriate approaches to eliminate the curing effect were identified. Sugar or MCC cores were layered with the model drugs carbamazepine, theophylline, propranolol HCl, tramadol HCl and metoprolol HCl using HPMC (5 or 25% w/w, based on drug) as a binder. Drug-layered pellets were coated with Kollicoat® SR 30D in a fluidized bed coater using TEC (10% w/w) as plasticizer and talc (35-100% w/w) as anti-tacking agent. Drug release, pellet properties (morphology, water uptake-weight loss and osmolality) and adhesion of the coating to the drug layer were investigated as a function of curing at 60°C or 60°C/75% RH for 24h. The film formation of the aqueous dispersion of Kollicoat® SR 30D was complete, and therefore, a strong curing effect (decrease in drug release) at elevated temperature and humidity (60°C/75% RH) could not be explained by the well-known hydroplasticization and the further gradual coalescence of the colloidal polymer particles. According to the provided mechanistic explanation, the observed curing effect was associated with (1) high flexibility of coating, (2) adhesion between coating and drug layer, (3) water retaining properties of the drug layer, and (4) osmotically active cores. Unwanted curing effects could be minimized/eliminated by the addition of talc or/and pore-forming water soluble polymers in the coating, increasing binder amount or applying an intermediate coating, by increasing the thickness of drug layer or using non-osmotic cores. A new insight into curing phenomena mainly associated with the adhesion between drug layer and coating was provided. Appropriate approaches to avoid unwanted curing effect were identified

  2. Flexible Graphene Composites for Human Space Flight Applications

    Sosa, Edward D.

    2013-01-01

    Graphene oxide allows for better dispersion stability in aqueous and organic solvents. Stabilizers provide dispersion of pristine graphene. Roll coating provide the best coverage of polyurethane sheets. Graphene and GO coated polyurethane used to fabricate flexible laminate composite. Permeation testing indicates that pristine graphene acts as a better gas barrier material. Continuous graphene films are expected to provide even better gas barrier properties.

  3. Mechanical properties of flexible knitted composites

    Haan, de J.; Peijs, A.A.J.M.

    1996-01-01

    This study investigates the influence of the matrix material and the degree of prestretch of a knitted fibre structure on the mechanical properties of knitted composites with low fibre volume fractions. By embedding a flexible textile structure in an elastomeric matrix, composite materials are

  4. Electroactive properties of flexible piezoelectric composites

    Sakamoto Walter Katsumi

    2001-01-01

    Full Text Available A flexible piezoelectric composite with 0-3 connectivity, made from Lead Zirconate Titanate (PZT powder and vegetable-based polyurethane (PU, was doped with small amount of semiconductor powder. As a result a composite with 0-0-3 connectivity was obtained. The nature of absorption and steady state electrical conduction and the dielectric behaviour have been studied for this ceramic/polymer composite. The dielectric loss processes of the composite were observed to be dominated by those the polymer. Adding a semiconductor phase in the composite the electrical conductivity can be controlled and a continuous electric flux path could be created between the PZT grains. This composite may be poled at low voltage and in shorter time compared with composites without a conductive phase.

  5. Flexible Composite-Material Pressure Vessel

    Brown, Glen; Haggard, Roy; Harris, Paul A.

    2003-01-01

    A proposed lightweight pressure vessel would be made of a composite of high-tenacity continuous fibers and a flexible matrix material. The flexibility of this pressure vessel would render it (1) compactly stowable for transport and (2) more able to withstand impacts, relative to lightweight pressure vessels made of rigid composite materials. The vessel would be designed as a structural shell wherein the fibers would be predominantly bias-oriented, the orientations being optimized to make the fibers bear the tensile loads in the structure. Such efficient use of tension-bearing fibers would minimize or eliminate the need for stitching and fill (weft) fibers for strength. The vessel could be fabricated by techniques adapted from filament winding of prior composite-material vessels, perhaps in conjunction with the use of dry film adhesives. In addition to the high-bias main-body substructure described above, the vessel would include a low-bias end substructure to complete coverage and react peak loads. Axial elements would be overlaid to contain damage and to control fiber orientation around side openings. Fiber ring structures would be used as interfaces for connection to ancillary hardware.

  6. MINEQL, Chemical Equilibrium Composition of Aqueous Systems

    Westall, John C.; Zachary, Joseph L.; Morel, Francois M.M.; Parsons, Ralph M.; Schweingruber, M.

    1994-01-01

    1 - Description of program or function: MINEQL is a subroutine package to calculate equilibrium composition of an aqueous system, accounting for mass transfer. MINEQL-EIR contains an additional base on enthalpy and heat capacity data and has the option to do calculations at temperatures different from 25 degrees C. 2 - Method of solution: In MINEQL, the Gibbs free-energy function is minimized and mass balance chemical reaction equations are solved simultaneously. In MINEQL-EIR, the iteration scheme to solve the system of equations has been improved to make the probability of divergence very small. 3 - Restrictions on the complexity of the problem: MINEQL does not take into account mass transfer of water molecules

  7. Non-aqueous electrochemical deposition of lead zirconate titanate films for flexible sensor applications

    Joseph, Sherin; Kumar, A. V. Ramesh; John, Reji

    2017-11-01

    Lead zirconate titanate (PZT) is one of the most important piezoelectric materials widely used for underwater sensors. However, PZTs are hard and non-compliant and hence there is an overwhelming attention devoted toward making it flexible by preparing films on flexible substrates by different routes. In this work, the electrochemical deposition of composition controlled PZT films over flexible stainless steel (SS) foil substrates using non-aqueous electrolyte dimethyl sulphoxide (DMSO) was carried out. Effects of various key parameters involved in electrochemical deposition process such as current density and time of deposition were studied. It was found that a current density of 25 mA/cm2 for 5 min gave a good film. The morphology and topography evaluation of the films was carried out by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively, which showed a uniform morphology with a surface roughness of 2 nm. The PZT phase formation was studied using X-ray diffraction (XRD) and corroborated with Raman spectroscopic studies. The dielectric constant, dielectric loss, hysteresis and I-V characteristics of the film was evaluated.

  8. Cellulose Nanofiber Composite Substrates for Flexible Electronics

    Ronald Sabo; Jung-Hun Seo; Zhenqiang Ma

    2012-01-01

    Flexible electronics have a large number of potential applications including malleable displays and wearable computers. The current research into high-speed, flexible electronic substrates employs the use of plastics for the flexible substrate, but these plastics typically have drawbacks, such as high thermal expansion coefficients. Transparent films made from...

  9. Influence of membrane composition on its flexibility

    Gerbelli, B.B.; Teixeira da Silva, E.R.; Oliveira, C.L.P.; Oliveira, E.A.

    2012-01-01

    Full text: Lamellar phases and vesicles composed of lipids have been used as model systems to investigate biological process related to cell membrane as well as promising carriers for drugs and gene therapy. The composition of the membrane determines its three dimensional shape and its properties such as rigidity and compressibility which play an important role on membrane fusion, protein adhesion, interactions between proteins, etc. We present systematic study of a lamellar system composed mainly of lecithin which is a biocompatible phospholipid and simusol, which is a mixture of fatty acids that acts as a cosurfactant introducing flexibility to the membrane. Using X ray scattering we determine the lamellar periodicity as a function of the hydration for different formulations of the membrane; ranging from 100 % to 50 % mass fraction of lecithin. The X-ray spectra are fitted using a 4 Gaussian model [1]that allows us to determine the lamellar periodicity and the Caille parameter [2]. The ideal swelling law relating the membrane volume fraction (φ m ) to the lamellar periodicity (D) is given by φ m =δ m /D, where δ m is the thickness membrane, however, when steric interactions are dominant with respect to electrostatic and van der Waals interactions, deviations from this behavior are expected [3]. We present experimental data illustrating the swelling behavior for the membrane compositions and the respective behavior of the hydration limit, membrane Luzzati [4], of the Caille parameter and qualitative interpretation of the interaction forces the systems studying the parameter membrane square amplitude fluctuation[5]. [1] Private communication with Prof. Dr. Cristiano Luis Pinto de Oliveira. [2] Caille A. et all, Acad. Sci. Paris B274 (1972) 891. [3] E. Kurtisovski et all, PRL 98, 258103 (2007). [4] Nagle et all, Curr Opin Struct Biol. 2000 Aug;10(4):474-80. [5] H. I. Petrache. Structure and interactions of fluid phospholipids bilayers measured by high resolution

  10. Tricolore. A flexible color scale for ternary compositions

    2018-01-01

    tricolore is an R library providing a flexible color scale for the visualization of three-part/ternary compositions. Its main functionality is to color-code any ternary composition as a mixture of three primary colours and to draw a suitable color-key. tricolore flexibly adapts to different...... visualisation challenges via - discrete and continuous color support - support for unbalanced compositional data via centering - support for data with very narrow range via scaling - hue, chroma and lightness options...

  11. Conductive polymer/metal composites for interconnect of flexible devices

    Kawakita, Jin; Hashimoto Shinoda, Yasuo; Shuto, Takanori; Chikyow, Toyohiro

    2015-06-01

    An interconnect of flexible and foldable devices based on advanced electronics requires high electrical conductivity, flexibility, adhesiveness on a plastic substrate, and efficient productivity. In this study, we investigated the applicability of a conductive polymer/metal composite to the interconnect of flexible devices. By combining an inkjet process and a photochemical reaction, micropatterns of a polypyrrole/silver composite were formed on flexible plastic substrates with an average linewidth of approximately 70 µm within 10 min. The conductivity of the composite was improved to 6.0 × 102 Ω-1·cm-1. From these results, it is expected that the conducting polymer/metal composite can be applied to the microwiring of flexible electronic devices.

  12. Influence of membrane composition on its flexibility

    Gerbelli, B.B.; Teixeira da Silva, E.R.; Oliveira, C.L.P.; Oliveira, E.A. [Universidade de Sao Paulo (USP), SP (Brazil)

    2012-07-01

    Full text: Lamellar phases and vesicles composed of lipids have been used as model systems to investigate biological process related to cell membrane as well as promising carriers for drugs and gene therapy. The composition of the membrane determines its three dimensional shape and its properties such as rigidity and compressibility which play an important role on membrane fusion, protein adhesion, interactions between proteins, etc. We present systematic study of a lamellar system composed mainly of lecithin which is a biocompatible phospholipid and simusol, which is a mixture of fatty acids that acts as a cosurfactant introducing flexibility to the membrane. Using X ray scattering we determine the lamellar periodicity as a function of the hydration for different formulations of the membrane; ranging from 100 % to 50 % mass fraction of lecithin. The X-ray spectra are fitted using a 4 Gaussian model [1]that allows us to determine the lamellar periodicity and the Caille parameter [2]. The ideal swelling law relating the membrane volume fraction ({phi}{sub m}) to the lamellar periodicity (D) is given by {phi}{sub m} ={delta}{sub m}/D, where {delta}{sub m} is the thickness membrane, however, when steric interactions are dominant with respect to electrostatic and van der Waals interactions, deviations from this behavior are expected [3]. We present experimental data illustrating the swelling behavior for the membrane compositions and the respective behavior of the hydration limit, membrane Luzzati [4], of the Caille parameter and qualitative interpretation of the interaction forces the systems studying the parameter membrane square amplitude fluctuation[5]. [1] Private communication with Prof. Dr. Cristiano Luis Pinto de Oliveira. [2] Caille A. et all, Acad. Sci. Paris B274 (1972) 891. [3] E. Kurtisovski et all, PRL 98, 258103 (2007). [4] Nagle et all, Curr Opin Struct Biol. 2000 Aug;10(4):474-80. [5] H. I. Petrache. Structure and interactions of fluid phospholipids

  13. Limited access: gender, occupational composition, and flexible work scheduling.

    Glauber, Rebecca

    2011-01-01

    The current study draws on national data to explore differences in access to flexible work scheduling by the gender composition of women's and men's occupations. Results show that those who work in integrated occupations are more likely to have access to flexible scheduling. Women and men do not take jobs with lower pay in return for greater access to flexibility. Instead, jobs with higher pay offer greater flexibility. Integrated occupations tend to offer the greatest access to flexible scheduling because of their structural locations. Part-time work is negatively associated with men's access to flexible scheduling but positively associated with women's access. Women have greater flexibility when they work for large establishments, whereas men have greater flexibility when they work for small establishments.

  14. Flexible Aqueous Lithium-Ion Battery with High Safety and Large Volumetric Energy Density.

    Dong, Xiaoli; Chen, Long; Su, Xiuli; Wang, Yonggang; Xia, Yongyao

    2016-06-20

    A flexible and wearable aqueous lithium-ion battery is introduced based on spinel Li1.1 Mn2 O4 cathode and a carbon-coated NASICON-type LiTi2 (PO4 )3 anode (NASICON=sodium-ion super ionic conductor). Energy densities of 63 Wh kg(-1) or 124 mWh cm(-3) and power densities of 3 275 W kg(-1) or 11.1 W cm(-3) can be obtained, which are seven times larger than the largest reported till now. The full cell can keep its capacity without significant loss under different bending states, which shows excellent flexibility. Furthermore, two such flexible cells in series with an operation voltage of 4 V can be compatible with current nonaqueous Li-ion batteries. Therefore, such a flexible cell can potentially be put into practical applications for wearable electronics. In addition, a self-chargeable unit is realized by integrating a single flexible aqueous Li-ion battery with a commercial flexible solar cell, which may facilitate the long-time outdoor operation of flexible and wearable electronic devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Towards flexibility in transactional service compositions

    Rinderle-Ma, S.; Grefen, P.W.P.J.; De Roure, D.; Thuraisingham, B.; Zhang, J.

    2014-01-01

    Complex services can be described by service compositions and executed by service orchestrations. Changing service compositions is a frequent requirement in practical settings. Changing the composition must not result in a violation of its functional or non-functional properties. Whereas functional

  16. Phytochemical Composition And Effect Of Aqueous Extract Of ...

    Phytochemical Composition And Effect Of Aqueous Extract Of Struchium sparganophora (L) On Cockroach Crude Extract – Induced Airway Inflammatory ... Similarly, mean percentages of neutrophils, lymphyocytes, and eosinophils in cockroach crude extract-induced rats administered with S. sparganophora crude extract ...

  17. A Study of Flexible Composites for Expandable Space Structures

    Scotti, Stephen J.

    2016-01-01

    Payload volume for launch vehicles is a critical constraint that impacts spacecraft design. Deployment mechanisms, such as those used for solar arrays and antennas, are approaches that have successfully accommodated this constraint, however, providing pressurized volumes that can be packaged compactly at launch and expanded in space is still a challenge. One approach that has been under development for many years is to utilize softgoods - woven fabric for straps, cloth, and with appropriate coatings, bladders - to provide this expandable pressure vessel capability. The mechanics of woven structure is complicated by a response that is nonlinear and often nonrepeatable due to the discrete nature of the woven fiber architecture. This complexity reduces engineering confidence to reliably design and certify these structures, which increases costs due to increased requirements for system testing. The present study explores flexible composite materials systems as an alternative to the heritage softgoods approach. Materials were obtained from vendors who utilize flexible composites for non-aerospace products to determine some initial physical and mechanical properties of the materials. Uniaxial mechanical testing was performed to obtain the stress-strain response of the flexible composites and the failure behavior. A failure criterion was developed from the data, and a space habitat application was used to provide an estimate of the relative performance of flexible composites compared to the heritage softgoods approach. Initial results are promising with a 25% mass savings estimated for the flexible composite solution.

  18. Flexible Nanocellulose - Nanoparticle Composites: Structures and Properties

    UTHPALA MANAVI GARUSINGHE

    2018-01-01

    Nanocellulose is biodegradable and renewable and has many attractive properties of technological interest. Therefore, nanocellulose can be converted into thin films, which is used in wide range of applications. However, the property range achievable with nanocellulose by itself still has limitations. This thesis focuses on the production of nanocellulose-inorganic nanoparticle composites to combine the advantage associated with both individual components together to extend the range of proper...

  19. Flexible and Self-Healing Aqueous Supercapacitors for Low Temperature Applications: Polyampholyte Gel Electrolytes with Biochar Electrodes.

    Li, Xinda; Liu, Li; Wang, Xianzong; Ok, Yong Sik; Elliott, Janet A W; Chang, Scott X; Chung, Hyun-Joong

    2017-05-10

    A flexible and self-healing supercapacitor with high energy density in low temperature operation was fabricated using a combination of biochar-based composite electrodes and a polyampholyte hydrogel electrolyte. Polyampholytes, a novel class of tough hydrogel, provide self-healing ability and mechanical flexibility, as well as low temperature operation for the aqueous electrolyte. Biochar is a carbon material produced from the low-temperature pyrolysis of biological wastes; the incorporation of reduced graphene oxide conferred mechanical integrity and electrical conductivity and hence the electrodes are called biochar-reduced-graphene-oxide (BC-RGO) electrodes. The fabricated supercapacitor showed high energy density of 30 Wh/kg with ~90% capacitance retention after 5000 charge-discharge cycles at room temperature at a power density of 50 W/kg. At -30 °C, the supercapacitor exhibited an energy density of 10.5 Wh/kg at a power density of 500 W/kg. The mechanism of the low-temperature performance excellence is likely to be associated with the concept of non-freezable water near the hydrophilic polymer chains, which can motivate future researches on the phase behaviour of water near polyampholyte chains. We conclude that the combination of the BC-RGO electrode and the polyampholyte hydrogel electrolyte is promising for supercapacitors for flexible electronics and for low temperature environments.

  20. Supercapacitors based on flexible graphene/polyaniline nanofiber composite films.

    Wu, Qiong; Xu, Yuxi; Yao, Zhiyi; Liu, Anran; Shi, Gaoquan

    2010-04-27

    Composite films of chemically converted graphene (CCG) and polyaniline nanofibers (PANI-NFs) were prepared by vacuum filtration the mixed dispersions of both components. The composite film has a layered structure, and PANI-NFs are sandwiched between CCG layers. Furthermore, it is mechanically stable and has a high flexibility; thus, it can be bent into large angles or be shaped into various desired structures. The conductivity of the composite film containing 44% CCG (5.5 x 10(2) S m(-1)) is about 10 times that of a PANI-NF film. Supercapacitor devices based on this conductive flexible composite film showed large electrochemical capacitance (210 F g(-1)) at a discharge rate of 0.3 A g(-1). They also exhibited greatly improved electrochemical stability and rate performances.

  1. Nanostructured graphene composite papers for highly flexible and foldable supercapacitors.

    Liu, Lili; Niu, Zhiqiang; Zhang, Li; Zhou, Weiya; Chen, Xiaodong; Xie, Sishen

    2014-07-23

    Reduced graphene oxide (rGO) and polyaniline (PANI) assemble onto the surface of cellulose fibers (CFs) and into the pores of CF paper, to form a hierarchical nanostructured PANI-rGO/CF composite paper. Based on these composite papers, flexible and foldable all-solid-state supercapacitors are achieved. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Bioinspired Transparent Laminated Composite Film for Flexible Green Optoelectronics.

    Lee, Daewon; Lim, Young-Woo; Im, Hyeon-Gyun; Jeong, Seonju; Ji, Sangyoon; Kim, Yong Ho; Choi, Gwang-Mun; Park, Jang-Ung; Lee, Jung-Yong; Jin, Jungho; Bae, Byeong-Soo

    2017-07-19

    Herein, we report a new version of a bioinspired chitin nanofiber (ChNF) transparent laminated composite film (HCLaminate) made of siloxane hybrid materials (hybrimers) reinforced with ChNFs, which mimics the nanofiber-matrix structure of hierarchical biocomposites. Our HCLaminate is produced via vacuum bag compressing and subsequent UV-curing of the matrix resin-impregnated ChNF transparent paper (ChNF paper). It is worthwhile to note that this new type of ChNF-based transparent substrate film retains the strengths of the original ChNF paper and compensates for ChNF paper's drawbacks as a flexible transparent substrate. As a result, compared with high-performance synthetic plastic films, such as poly(ethylene terephthalate), poly(ether sulfone), poly(ethylene naphthalate), and polyimide, our HCLaminate is characterized to exhibit extremely smooth surface topography, outstanding optical clarity, high elastic modulus, high dimensional stability, etc. To prove our HCLaminate as a substrate film, we use it to fabricate flexible perovskite solar cells and a touch-screen panel. As far as we know, this work is the first to demonstrate flexible optoelectronics, such as flexible perovskite solar cells and a touch-screen panel, actually fabricated on a composite film made of ChNF. Given its desirable macroscopic properties, we envision our HCLaminate being utilized as a transparent substrate film for flexible green optoelectronics.

  3. Flexible, wearable, and functional graphene-textile composites

    Liu, Ying; Zhang, Kun-Ning; Zhang, Ying; Tao, Lu-Qi; Li, Yu-Xing; Wang, Dan-Yang; Yang, Yi; Ren, Tian-Ling

    2017-06-01

    In this paper, a flexible, wearable, and functional graphene-textile composite is demonstrated. Laser scribing technology is applied to fabricate a graphene film. The thin layer of polydimethylsiloxane is covered on the surface of the graphene-textile film evenly, which would improve the abrasive resistance of the film, enhance the ability to adapt to environmental changes, and extend the service life, while maintaining the device's excellent flexibility and comfort. The graphene-textile composite can achieve constant temperature heating by controlling the input voltage, detect the human movement, and perceive the human pulse signal. The composite presents great commercial prospects and a large value in the medical, daily wear, and other areas that are closely related to human lives.

  4. Flexible composite material with phase change thermal storage

    Buckley, Theresa M. (Inventor)

    2001-01-01

    A highly flexible composite material having a flexible matrix containing a phase change thermal storage material. The composite material can be made to heat or cool the body or to act as a thermal buffer to protect the wearer from changing environmental conditions. The composite may also include an external thermal insulation layer and/or an internal thermal control layer to regulate the rate of heat exchange between the composite and the skin of the wearer. Other embodiments of the PCM composite also provide 1) a path for evaporation or direct absorption of perspiration from the skin of the wearer for improved comfort and thermal control, 2) heat conductive pathways within the material for thermal equalization, 3) surface treatments for improved absorption or rejection of heat by the material, and 4) means for quickly regenerating the thermal storage capacity for reuse of the material. Applications of the composite materials are also described which take advantage of the composite's thermal characteristics. The examples described include a diver's wet suit, ski boot liners, thermal socks, ,gloves and a face mask for cold weather activities, and a metabolic heating or cooling blanket useful for treating hypothermia or fever patients in a medical setting and therapeutic heating or cooling orthopedic joint supports.

  5. Investigations of carbon nanotubes and polyacrylonitrile composites for flexible textronics

    Sowiński, J.; Wróblewski, G.; Janczak, D.; Jakubowska, M.

    2017-08-01

    Thin composite layers based on polyacrylonitrile (PAN) and carbon nanotubes (CNT) were fabricated by means of spray coating with pneumatic atomization. Research was conducted to achieve transparent and flexible electrodes. Prepared suspensions in different proportions of functional phase provided good dispersion quality of CNTs and the stability. The carbon nanotubes were dispersed in dimethylformamide and then added to polyacrylonitrile solution. Suspension was sprayed onto Polyethylene terephthalate (PET) foil. After thermal treatment, samples were mechanically and electrically tested. Thanks to carbon nanomaterials used in prepared coatings, high electrical conductivity and mechanical resistance was observed. Use of a polyacrylonitrile guarantee the flexibility of electrodes and high potential in integration with polyacrylonitrile based fabrics.

  6. Flexible Multibody Systems Models Using Composite Materials Components

    Neto, Maria Augusta; Ambr'osio, Jorge A. C.; Leal, Rog'erio Pereira

    2004-01-01

    The use of a multibody methodology to describe the large motion of complex systems that experience structural deformations enables to represent the complete system motion, the relative kinematics between the components involved, the deformation of the structural members and the inertia coupling between the large rigid body motion and the system elastodynamics. In this work, the flexible multibody dynamics formulations of complex models are extended to include elastic components made of composite materials, which may be laminated and anisotropic. The deformation of any structural member must be elastic and linear, when described in a coordinate frame fixed to one or more material points of its domain, regardless of the complexity of its geometry. To achieve the proposed flexible multibody formulation, a finite element model for each flexible body is used. For the beam composite material elements, the sections properties are found using an asymptotic procedure that involves a two-dimensional finite element analysis of their cross-section. The equations of motion of the flexible multibody system are solved using an augmented Lagrangian formulation and the accelerations and velocities are integrated in time using a multi-step multi-order integration algorithm based on the Gear method

  7. Water based, solution-processable, transparent and flexible graphene oxide composite as electrodes in organic solar cell application

    Lima, L F; Matos, C F; Gonçalves, L C; Roman, L S; Salvatierra, R V; Zarbin, A J G; Cava, C E

    2016-01-01

    In this work we propose an easy method to achieve a conductive, transparent and flexible graphene oxide (GO)-based composite thin film from an aqueous dispersion. We investigated the blend ratio between GO and the conjugated polymer poly(3,4–ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) by comparing the thin film optical transmittance, sheet resistance, morphology and mechanical stability. It was found that reasonable values of transmittance and resistivity coupled with its excellent flexibility – the conductivity remains almost the same even after 1000 bends cycles – make this composite very attracting for flexible optoelectronic applications. Thus, these films were used as transparent electrodes in a bilayer structured organic solar cell and the device architecture PET/GO:PEDOT/F8T2/C 60 /Al could reach a power conversion efficiency around 1.10%. This result presents a better performance compared with pristine PEDOT produced with similar parameters. (paper)

  8. Designing magnetic composite materials using aqueous magnetic fluids

    Galicia, J A; Cousin, F; Guemghar, D; Menager, C; Cabuil, V

    2003-01-01

    In this paper, we report on how to take advantage of good knowledge of both the chemistry and the stability of an aqueous magnetic colloidal suspension to realize different magnetic composites. The osmotic pressure of the magnetic nanoparticles is set prior to the realization of the composite to a given value specially designed for the purpose for each hybrid material: magnetic particles in polymer networks, particles as probes for studying the structure of clay suspensions and shape modification of giant liposomes. First, we show that the introduction of magnetic particles in polyacrylamide gels enhances their Young modulus and reduces the swelling caused by water. The particles cause both a mechanical and an osmotic effect. The latter is strongly dependent on the ionic strength and is attributed to an attraction between particles and the polymeric matrix. In the second part, we determine the microscopic structure of suspensions of laponite as a function of concentration, by combining SANS and magneto-optica...

  9. Flexible Aqueous Li-Ion Battery with High Energy and Power Densities.

    Yang, Chongyin; Ji, Xiao; Fan, Xiulin; Gao, Tao; Suo, Liumin; Wang, Fei; Sun, Wei; Chen, Ji; Chen, Long; Han, Fudong; Miao, Ling; Xu, Kang; Gerasopoulos, Konstantinos; Wang, Chunsheng

    2017-11-01

    A flexible and wearable aqueous symmetrical lithium-ion battery is developed using a single LiVPO 4 F material as both cathode and anode in a "water-in-salt" gel polymer electrolyte. The symmetric lithium-ion chemistry exhibits high energy and power density and long cycle life, due to the formation of a robust solid electrolyte interphase consisting of Li 2 CO 3 -LiF, which enables fast Li-ion transport. Energy densities of 141 Wh kg -1 , power densities of 20 600 W kg -1 , and output voltage of 2.4 V can be delivered during >4000 cycles, which is far superior to reported aqueous energy storage devices at the same power level. Moreover, the full cell shows unprecedented tolerance to mechanical stress such as bending and cutting, where it not only does not catastrophically fail, as most nonaqueous cells would, but also maintains cell performance and continues to operate in ambient environment, a unique feature apparently derived from the high stability of the "water-in-salt" gel polymer electrolyte. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Flexible asymmetric supercapacitors with high energy and high power density in aqueous electrolytes

    Cheng, Yingwen; Zhang, Hongbo; Lu, Songtao; Varanasi, Chakrapani V.; Liu, Jie

    2013-01-01

    Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO2, activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of the original capacitance retained when the scan rate was increased from 2 mV s-1 to 500 mV s-1. Owing to the unique composite structure, these supercapacitors were able to deliver high energy density (24 W h kg-1) under high power density (7.8 kW kg-1) conditions. These features could enable supercapacitor based energy storage systems to be very attractive for a variety of critical applications, such as the power sources in hybrid electric vehicles and the back-up powers for wind and solar energy, where both high energy density and high power density are required.Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO2, activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of

  11. Flexible Tactile Sensing Based on Piezoresistive Composites: A Review

    Stassi, Stefano; Cauda, Valentina; Canavese, Giancarlo; Pirri, Candido Fabrizio

    2014-01-01

    The large expansion of the robotic field in the last decades has created a growing interest in the research and development of tactile sensing solutions for robot hand and body integration. Piezoresistive composites are one of the most widely employed materials for this purpose, combining simple and low cost preparation with high flexibility and conformability to surfaces, low power consumption, and the use of simple read-out electronics. This work provides a review on the different type of composite materials, classified according to the conduction mechanism and analyzing the physics behind it. In particular piezoresistors, strain gauges, percolative and quantum tunnelling devices are reviewed here, with a perspective overview on the most used filler types and polymeric matrices. A description of the state-of-the-art of the tactile sensor solutions from the point of view of the architecture, the design and the performance is also reviewed, with a perspective outlook on the main promising applications. PMID:24638126

  12. Flexible organization of floor composition and flexible organization of dwelling space as a response to contemporary market demands

    Jovanović Goran

    2007-01-01

    The paper presents the application of the principle of flexibility of architectonic space on the concrete example of flat composition. This example demonstrates that with a proper choice of structural spans dimensions and regular arrangement of sanitary and ventilation vertical assemblies, a structure with high flexibility in terms of flat space organization and floor space organization, can be achieved.

  13. Use of flexible engineered cementitious composite in buildings

    Khitab, A.; Nadeem, M.; Hussain, S.

    2011-01-01

    This article describes the applications and benefits of a recently developed smart building material namely Engineered cementitious composite (ECC), also known as flexible or bendable concrete. Conventional concretes have a strain capacity of only 0.1 percent and are highly brittle and rigid. This lack of bend ability is a major cause of failure under strain and has been a pushing factor in the development of an elegant material which is capable to exhibit an enhanced flexibility. An ECC has a strain capacity of more than 3 percent and thus acts more like a ductile metal rather than like a brittle glass. The aim of this paper is to highlight a probable success of ECC in terms of industrial and commercial use in Pakistan. With the introduction of flexible concrete in building technology, it is likely to have safer and more durable construction. The material is expected to display reduced detrimental impacts on the natural environment. A bendable concrete is composed of all the ingredients of a traditional concrete minus coarse aggregates or crushed stones and is reinforced with micro mechanically designed polymer fibers. The mechanism of action of the micro-polymeric fibers in concrete has also been emphasized. The principles of mix designs of the mortar incorporating fibers to make an ECC have also been explained. It has also been mentioned in detail as how this technology can be used to enhance the flexibility of some modern concrete types like flowing concrete, self-compacting concrete, and lightweight concrete. ECC is a green construction material. The possible benefits like environment friendliness, cost effectiveness, and durability have been also been elucidated in the paper. (author)

  14. Preparation of Supercapacitors on Flexible Substrates with Electrodeposited PEDOT/Graphene Composites.

    Lehtimäki, Suvi; Suominen, Milla; Damlin, Pia; Tuukkanen, Sampo; Kvarnström, Carita; Lupo, Donald

    2015-10-14

    Composite films consisting of poly(3,4-ethylenedioxythiophene) (PEDOT) and graphene oxide (GO) were electrochemically polymerized by electrooxidation of EDOT in ionic liquid (BMIMBF4) onto flexible electrode substrates. Two polymerization approaches were compared, and the cyclic voltammetry (CV) method was found to be superior to potentiostatic polymerization for the growth of PEDOT/GO films. After deposition, incorporated GO was reduced to rGO by a rapid electrochemical method of repetitive cathodic potential cycling, without using any reducing reagents. The films were characterized in 3-electrode configuration in BMIMBF4. Symmetric supercapacitors with aqueous electrolyte were assembled from the composite films and characterized through cyclic voltammetry and galvanostatic discharge tests. It was shown that PEDOT/rGO composites have better capacitive properties than pure PEDOT or the unreduced composite film. The cycling stability of the supercapacitors was also tested, and the results indicate that the specific capacitance still retains well over 90% of the initial value after 2000 consecutive charging/discharging cycles. The supercapacitors were demonstrated as energy storages in a room light energy harvester with a printed organic solar cell and printed electrochromic display. The results are promising for the development of energy-autonomous, low-power, and disposable electronics.

  15. Polyampholyte hydrogel electrolytes for flexible and self-healing aqueous supercapacitor for low temperature applications

    Chung, Hyun-Joong; Li, Xinda

    Quenched polyampholytes provide a novel class of tough hydrogel that has self-healing ability, strong adhesion, and mechanical flexibility. In this study, we show that the polyampholyte hydrogels can be utilized as an aqueous gel electrolyte material that is especially useful for low temperature operations; at -30 °C, energy density of 10.5 Wh/kg at a power density of 500 W/kg was achieved. The high performance at the low temperature is associated to the concept of non-freezable water near the hydrophilic polymer chains. A comparison between differential scanning calorimetry (DSC) measurements for polyampholytes that contained KOH and neat KOH solution revealed that increased amount of water molecules become non-freezable when the solution is contained in the hydrogel networks. In addition, the crosslinked network structure of the polyampholyte chains disrupts the crystalline growth of ice, resulting in `slush-like' ice formation. The interplay between the increased amount of unfrozen water and the limited growth of ice crystals leads to the enhanced supercapacitor performance at low temperatures.

  16. Fabrication of flexible piezoelectric PZT/fabric composite.

    Chen, Caifeng; Hong, Daiwei; Wang, Andong; Ni, Chaoying

    2013-01-01

    Flexible piezoelectric PZT/fabric composite material is pliable and tough in nature which is in a lack of traditional PZT patches. It has great application prospect in improving the sensitivity of sensor/actuator made by piezoelectric materials especially when they are used for curved surfaces or complicated conditions. In this paper, glass fiber cloth was adopted as carrier to grow PZT piezoelectric crystal particles by hydrothermal method, and the optimum conditions were studied. The results showed that the soft glass fiber cloth was an ideal kind of carrier. A large number of cubic-shaped PZT nanocrystallines grew firmly in the carrier with a dense and uniform distribution. The best hydrothermal condition was found to be pH 13, reaction time 24 h, and reaction temperature 200°C.

  17. Flexibility.

    Humphrey, L. Dennis

    1981-01-01

    Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

  18. Flexible all-solid-state high-performance supercapacitor based on electrochemically synthesized carbon quantum dots/polypyrrole composite electrode

    Jian, Xuan; Yang, Hui-min; Li, Jia-gang; Zhang, Er-hui; Cao, Le-le; Liang, Zhen-hai

    2017-01-01

    Highlights: • Porous nanostructure carbon quantum dots/polypyrrole composite film was successfully synthesized by direct electrochemical method. • A flexible all-solid-state supercapacitor device was fabricated using the carbon quantum dots/polypyrrole composite electrode. • The flexible supercapacitor exhibits high specific capacitance, excellent reliability and long cycling life. - Abstract: Recently, carbon quantum dots (CQDs) as a new zero-dimensional carbon nanomaterial have become a focus in electrochemical energy storage. In this paper, flexible all-solid-state supercapacitors (ASSSs) were electrochemically synthesized by on-step co-deposition of appropriate amounts of pyrrole monomer and CQDs in aqueous solution. The different electrodeposition time plays an important role in controlling morphologies of stainless steel wire meshes (SSWM)-supported CQDs/PPy composite film. The morphologies and compositions of the obtained CQDs/PPy composite electrodes were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectrum and X-ray photoelectron spectroscopy (XPS). Furthermore, a novel flexible ASSS device was fabricated using CQDs/PPy composite as the electrode and separated by polyvinyl alcohol/LiCl gel electrolyte. Benefiting from superior electrochemical properties of CQDs and PPy, the as-prepared CQDs/PPy composite ASSSs exhibit outstanding electrochemical performance with the areal capacitance 315 mF cm −2 (corresponding to specific capacitance of 308 F g −1 ) at a current density of 0.2 mA cm −2 and long cycle life with 85.7% capacitance retention after 2 000 cycles.

  19. Structural evolution of chitosan–palygorskite composites and removal of aqueous lead by composite beads

    Rusmin, Ruhaida; Sarkar, Binoy; Liu, Yanju; McClure, Stuart; Naidu, Ravi

    2015-01-01

    Graphical abstract: - Highlights: • Facile preparation of chitosan–palygorskite composite beads demonstrated. • Components’ mass ratio impacted structural characteristics of composites. • Mechanism of composite formation and structure of composite beads proposed. • Composite beads adsorbed significantly greater amount of Pb than pristine materials. • In-depth investigation done on Pb adsorption mechanisms. - Abstract: This paper investigates the structural evolution of chitosan–palygorskite (CP) composites in relation to variable mass ratios of their individual components. The composite beads’ performance in lead (Pb) adsorption from aqueous solution was also examined. The composite beads were prepared through direct dispersion of chitosan and palygorskite at 1:1, 1:2 and 2:1 mass ratios (CP1, CP2 and C2P, respectively). Analyses by Fourier transform Infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the dependence of the composites’ structural characteristics on their composition mass ratio. The chitosan–palygorskite composite beads exhibited a better Pb adsorption performance than the pristine materials (201.5, 154.5, 147.1, 27.7 and 9.3 mg g"−"1 for CP1, C2P, CP2, chitosan and palygorskite, respectively). Adsorption of Pb by CP1 and CP2 followed Freundlich isothermal model, while C2P fitted to Langmuir model. Kinetic studies showed that adsorption by all the composites fitted to the pseudo-second order model with pore diffusion also acting as a major rate governing step. The surface properties and specific interaction between chitosan and palygorskite in the composites were the most critical factors that influenced their capabilities in removing toxic metals from water.

  20. Structural evolution of chitosan–palygorskite composites and removal of aqueous lead by composite beads

    Rusmin, Ruhaida, E-mail: ruhaida.rusmin@mymail.unisa.edu.au [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Faculty of Applied Sciences, Universiti Teknologi MARA Negeri Sembilan, Kuala Pilah 72000 (Malaysia); Sarkar, Binoy, E-mail: binoy.sarkar@unisa.edu.au [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC CARE – Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106 (Australia); Liu, Yanju [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC CARE – Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106 (Australia); McClure, Stuart [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); Naidu, Ravi, E-mail: Ravi.Naidu@newcastle.edu.au [CERAR – Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095 (Australia); CRC CARE – Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, P.O. Box 486, Salisbury, SA 5106 (Australia)

    2015-10-30

    Graphical abstract: - Highlights: • Facile preparation of chitosan–palygorskite composite beads demonstrated. • Components’ mass ratio impacted structural characteristics of composites. • Mechanism of composite formation and structure of composite beads proposed. • Composite beads adsorbed significantly greater amount of Pb than pristine materials. • In-depth investigation done on Pb adsorption mechanisms. - Abstract: This paper investigates the structural evolution of chitosan–palygorskite (CP) composites in relation to variable mass ratios of their individual components. The composite beads’ performance in lead (Pb) adsorption from aqueous solution was also examined. The composite beads were prepared through direct dispersion of chitosan and palygorskite at 1:1, 1:2 and 2:1 mass ratios (CP1, CP2 and C2P, respectively). Analyses by Fourier transform Infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the dependence of the composites’ structural characteristics on their composition mass ratio. The chitosan–palygorskite composite beads exhibited a better Pb adsorption performance than the pristine materials (201.5, 154.5, 147.1, 27.7 and 9.3 mg g{sup −1} for CP1, C2P, CP2, chitosan and palygorskite, respectively). Adsorption of Pb by CP1 and CP2 followed Freundlich isothermal model, while C2P fitted to Langmuir model. Kinetic studies showed that adsorption by all the composites fitted to the pseudo-second order model with pore diffusion also acting as a major rate governing step. The surface properties and specific interaction between chitosan and palygorskite in the composites were the most critical factors that influenced their capabilities in removing toxic metals from water.

  1. Phytochemical composition and acute toxicity evaluation of aqueous ...

    This study was carried out to determine the phytochemical constituents and acute toxicity of the aqueous root bark extract of Securidaca longipedunculata Linn. The result of phytochemical screening revealed the presence of some secondary metabolites of pharmacological significance in the aqueous root bark extract ...

  2. All-solid-state flexible microsupercapacitors based on reduced graphene oxide/multi-walled carbon nanotube composite electrodes

    Mao, Xiling; Xu, Jianhua; He, Xin; Yang, Wenyao; Yang, Yajie; Xu, Lu; Zhao, Yuetao; Zhou, Yujiu

    2018-03-01

    All-solid-state flexible microsupercapacitors have been intensely investigated in order to meet the rapidly growing demands for portable microelectronic devices. Herein, we demonstrate a facile, readily scalable and cost-effective laser induction process for preparing reduced graphene oxide/multi-walled carbon nanotube composite, which can be used as the interdigital electrodes in microsupercapacitors. The obtained composite exhibits high volumetric capacitance about 49.35 F cm-3, which is nearly 5 times higher than that of the pristine reduced graphene oxide film in aqueous 1.0 M H2SO4 solution (measured at a current density of 5 A cm-3 in a three-electrode testing). Additionally, an all-solid-state flexible microsupercapacitor employing these composite electrodes with PVA/H3PO4 gel electrolyte delivers high volumetric energy density of 6.47 mWh cm-3 at 10 mW cm-3 under the current density of 20 mA cm-3 as well as achieve excellent cycling stability retaining 88.6% of its initial value and outstanding coulombic efficiency after 10,000 cycles. Furthermore, the microsupercapacitors array connected in series/parallel can be easily adjusted to achieve the demands in practical applications. Therefore, this work brings a promising new candidate of prepare technologies for all-solid-state flexible microsupercapacitors as miniaturized power sources used in the portable and wearable electronics.

  3. Hierarchical porous graphene/polyaniline composite film with superior rate performance for flexible supercapacitors.

    Meng, Yuena; Wang, Kai; Zhang, Yajie; Wei, Zhixiang

    2013-12-23

    A highly flexible graphene free-standing film with hierarchical structure is prepared by a facile template method. With a porous structure, the film can be easily bent and cut, and forms a composite with another material as a scaffold. The 3D graphene film exhibits excellent rate capability and its capacitance is further improved by forming a composite with polyaniline nanowire arrays. The flexible hierarchical composite proves to be an excellent electrode material for flexible supercapacitors. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Flexible aerogel composite for mechanical stability and process of fabrication

    Coronado, P.R.; Poco, J.F.

    1999-10-26

    A flexible aerogel and process of fabrication are disclosed. An aerogel solution is mixed with fibers in a mold and allowed to gel. The gel is then processed by supercritical extraction, or by air drying, to produce a flexible aerogel formed to the shape of the mold. The flexible aerogel has excellent thermal and acoustic properties, and can be utilized in numerous applications, such as for energy absorption, insulation (temperature and acoustic), to meet the contours of aircraft shapes, and where space is limited since an inch of aerogel is a 4--5 times better insulator than an inch of fiberglass. The flexible aerogel may be of an inorganic (silica) type or an organic (carbon) type, but containing fibers, such as glass or carbon fibers.

  5. Flexible aerogel composite for mechanical stability and process of fabrication

    Coronado, Paul R.; Poco, John F.

    1999-01-01

    A flexible aerogel and process of fabrication. An aerogel solution is mixed with fibers in a mold and allowed to gel. The gel is then processed by supercritical extraction, or by air drying, to produce a flexible aerogel formed to the shape of the mold. The flexible aerogel has excellent thermal and acoustic properties, and can be utilized in numerous applications, such as for energy absorption, insulation (temperature and acoustic), to meet the contours of aircraft shapes, and where space is limited since an inch of aerogel is a 4-5 times better insulator than an inch of fiberglass. The flexible aerogel may be of an inorganic (silica) type or an organic (carbon) type, but containing fibers, such as glass or carbon fibers.

  6. Flexible aerogel composite for mechanical stability and process of fabrication

    Coronado, P.R.; Poco, J.F.

    2000-07-11

    A flexible aerogel and process of fabrication are disclosed. An aerogel solution is mixed with fibers in a mold and allowed to gel. The gel is then processed by supercritical extraction, or by air drying, to produce a flexible aerogel formed to the shape of the mold. The flexible aerogel has excellent thermal and acoustic properties, and can be utilized in numerous applications, such as for energy absorption, insulation (temperature and acoustic), to meet the contours of aircraft shapes, and where space is limited since an inch of aerogel is a 4--5 times better insulator than an inch of fiberglass. The flexible aerogel may be of an inorganic (silica) type or an organic (carbon) type, but containing fibers, such as glass or carbon fibers.

  7. Rapidly Responsive and Flexible Chiral Nematic Cellulose Nanocrystal Composites as Multifunctional Rewritable Photonic Papers with Eco-Friendly Inks.

    Wan, Hao; Li, Xiaofeng; Zhang, Liang; Li, Xiaopeng; Liu, Pengfei; Jiang, Zhiguo; Yu, Zhong-Zhen

    2018-02-14

    Rapidly responsive and flexible photonic papers are manufactured by coassembly of cellulose nanocrystals (CNCs) and waterborne polyurethane (WPU) latex for fully taking advantage of the chiral nematic structure of CNCs and the flexibility of WPU elastomer. The resulting CNC/WPU composite papers exhibit not only tunable iridescent colors by adjusting the helical pitch size, but also instant optical responses to water and wet gas, ascribed to the easy chain movement of the elastomeric WPU that does not restrict the fast water absorption-induced swelling of CNCs. By choosing water or NaCl aqueous solutions as inks, the colorful patterns on the CNC/WPU photonic paper can be made temporary, durable, or even disguisable. In addition, the photonic paper is simultaneously rewritable for all these three types of patterns, and the disguisable patterns, which are invisible at normal times and show up under stimuli, exhibit a quick reveal conversion just by exhaling on the paper. The rewritability, rapid responsibility, easy fabrication, and the eco-friendly nature of the inks make the flexible photonic paper/ink combination highly promising in sensors, displays, and photonic circuits.

  8. Composition dependent non-ideality in aqueous binary mixtures as ...

    SBBM) where two constituents dislike each other, yet remain macroscopically homogeneous at intermediate to high temperatures. Interestingly, we find that the origin of strong composition dependent non-ideal behaviour lies in its phase ...

  9. Deployment Testing of Flexible Composite Hinges in Bi-Material Beams

    Sauder, Jonathan F.; Trease, Brian

    2016-01-01

    Composites have excellent properties for strength, thermal stability, and weight. However, they are traditionally highly rigid, and when used in deployable structures require hinges bonded to the composite material, which increases complexity and opportunities for failure. Recent research in composites has found by adding an elastomeric soft matrix, often silicone instead of an epoxy, the composite becomes flexible. This work explores the deployment repeatability of silicone matrix composite hinges which join rigid composite beams. The hinges were found to have sub-millimeter linear deployment repeatability, and sub-degree angular deployment repeatability. Also, an interesting relaxation effect was discovered, as a hinges deployment error would decrease with time.

  10. The aqueous corrosion behavior of technetium - Alloy and composite materials

    Jarvinen, G.; Kolman, D.; Taylor, C.; Goff, G.; Cisneros, M.; Mausolf, E.; Poineau, F.; Koury, D.; Czerwinski, K.

    2013-01-01

    Metal waste forms are under study as possible disposal forms for technetium and other fission products. The alloying of Tc is desirable to reduce the melting point of the Tc-containing metal waste form and potentially improve its corrosion resistance. Technetium-nickel composites were made by mixing the two metal powders and pressing the mixture to make a pellet. The as-pressed composite materials were compared to sintered composites and alloys of identical composition in electrochemical corrosion tests. As-pressed samples were not robust enough for fine polishing and only a limited number of corrosion tests were performed. Alloys and composites with 10 wt% Tc appear to be more corrosion resistant at open circuit than the individual components based on linear polarization resistance and polarization data. The addition of 10 wt% Tc to Ni appears beneficial at open circuit, but detrimental upon anodic polarization. Qualitatively, the polarizations of 10 wt% Tc alloys and composites appear like crude addition of Tc plus Ni. The 1 wt% Tc alloys behave like pure Ni, but some effect of Tc is seen upon polarization. Cathodic polarization of Tc by Ni appears feasible based on open circuit potential measurements, however, zero resistance ammetry and solution measurements are necessary to confirm cathodic protection

  11. The aqueous corrosion behavior of technetium - Alloy and composite materials

    Jarvinen, G.; Kolman, D.; Taylor, C.; Goff, G.; Cisneros, M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Mausolf, E.; Poineau, F.; Koury, D.; Czerwinski, K. [Department of Chemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154 (United States)

    2013-07-01

    Metal waste forms are under study as possible disposal forms for technetium and other fission products. The alloying of Tc is desirable to reduce the melting point of the Tc-containing metal waste form and potentially improve its corrosion resistance. Technetium-nickel composites were made by mixing the two metal powders and pressing the mixture to make a pellet. The as-pressed composite materials were compared to sintered composites and alloys of identical composition in electrochemical corrosion tests. As-pressed samples were not robust enough for fine polishing and only a limited number of corrosion tests were performed. Alloys and composites with 10 wt% Tc appear to be more corrosion resistant at open circuit than the individual components based on linear polarization resistance and polarization data. The addition of 10 wt% Tc to Ni appears beneficial at open circuit, but detrimental upon anodic polarization. Qualitatively, the polarizations of 10 wt% Tc alloys and composites appear like crude addition of Tc plus Ni. The 1 wt% Tc alloys behave like pure Ni, but some effect of Tc is seen upon polarization. Cathodic polarization of Tc by Ni appears feasible based on open circuit potential measurements, however, zero resistance ammetry and solution measurements are necessary to confirm cathodic protection.

  12. Use of the PISCES Database: power plant aqueous stream compositions

    Behrens, G.P.; Orr, D.A.; Wetherold, R.G.; O'Neil, B.T.

    1996-01-01

    The Power Plant Integrated Systems: Chemical Emissions Studies (PISCES) Database sponsored by the Electric Power Research Institute is a powerful tool for evaluating and comparing the level of trace substances in power plant process streams. In this paper, data are presented on the level of several selected trace metals found in a few of the aqueous streams present in power plants. A brief discussion of other features of the Database is presented. The majority of the data is for coal fired power plants, with only 5% pertaining to oil and gas. Sources of pollution include: ash streams; cooling water; coal pile runoff; FGD liquids; makeup water; and wastewater. 11 refs., 10 figs., 1 tab

  13. Soft and flexible conductive PDMS/MWCNT composites

    Hassouneh, Suzan Sager; Yu, Liyun; Skov, Anne Ladegaard

    2017-01-01

    (trifluoromethanesulfonyl)imide, was used to pre-disperse MWCNT in a MWCNT/IL-gel that was used for preparation of MWCVNT/PDMS composites. The method was seen to be effective at low levels of MWCNT, but required combination with a roll mill to obtain a stable dispersion at 4 wt % MWCNT. With higher amounts of MWCNT a reduction...... for preparation of MWCNT/PDMS composites. Composites prepared by use of the IL dispersion method, use of a roll mill or by use of the f-MWCNT all had conductivities around 0.005–0.01 s/cm and retained conductivity upon extension....

  14. Mechanism Design and Testing of a Self-Deploying Structure Using Flexible Composite Tape Springs

    Footdale, Joseph N.; Murphey, Thomas W.

    2014-01-01

    The detailed mechanical design of a novel deployable support structure that positions and tensions a membrane optic for space imagining applications is presented. This is a complex three-dimensional deployment using freely deploying rollable composite tape spring booms that become load bearing structural members at full deployment. The deployment tests successfully demonstrate a new architecture based on rolled and freely deployed composite tape spring members that achieve simultaneous deployment without mechanical synchronization. Proper design of the flexible component mounting interface and constraint systems, which were critical in achieving a functioning unit, are described. These flexible composite components have much potential for advancing the state of the art in deployable structures, but have yet to be widely adopted. This paper demonstrates the feasibility and advantages of implementing flexible composite components, including the design details on how to integrate with required traditional mechanisms.

  15. All-solid state flexible supercapacitors based on graphene/polymer composites

    Kim, Jung Won; Choi, Bong Gill, E-mail: bgchoi@kangwon.ac.kr

    2015-06-01

    Recent advances in lightweight, flexible, and wearable electronic equipment has led to advancements in the development of sufficiently compact and flexible energy storage. A challenge remains to integrate the storage elements as closely as possible within a fully flexible device. Here, we demonstrate the fabrication of all-solid state flexible supercapacitors with the integration of two electrodes that consist of graphene/polymer composites. Robust conductive free-standing thin graphene/polymer composite electrodes were prepared through a simple “physical grinding” process. As-prepared composite electrodes store energy up to a reversible gravimetric capacitance of 90.6 F/g, at a constant current density of 0.5 A/g while also delivering long-term durability (90% retention) for excess of five-thousands of cycles. Notably, the enhancement of mechanical properties of supercapacitors enables them to maintain their electrochemical performance even when twisted or folded. This straightforward approach to the fabrication of fully flexible supercapacitors provides new design opportunities within wearable electronics and electrochemical applications. - Highlights: • All solid-sate supercapacitors were fabricated using graphene/polymer composite electrodes. • Supercapacitor devices show an excellent mechanical flexibility. • High electrochemical performances were demonstrated.

  16. All-solid state flexible supercapacitors based on graphene/polymer composites

    Kim, Jung Won; Choi, Bong Gill

    2015-01-01

    Recent advances in lightweight, flexible, and wearable electronic equipment has led to advancements in the development of sufficiently compact and flexible energy storage. A challenge remains to integrate the storage elements as closely as possible within a fully flexible device. Here, we demonstrate the fabrication of all-solid state flexible supercapacitors with the integration of two electrodes that consist of graphene/polymer composites. Robust conductive free-standing thin graphene/polymer composite electrodes were prepared through a simple “physical grinding” process. As-prepared composite electrodes store energy up to a reversible gravimetric capacitance of 90.6 F/g, at a constant current density of 0.5 A/g while also delivering long-term durability (90% retention) for excess of five-thousands of cycles. Notably, the enhancement of mechanical properties of supercapacitors enables them to maintain their electrochemical performance even when twisted or folded. This straightforward approach to the fabrication of fully flexible supercapacitors provides new design opportunities within wearable electronics and electrochemical applications. - Highlights: • All solid-sate supercapacitors were fabricated using graphene/polymer composite electrodes. • Supercapacitor devices show an excellent mechanical flexibility. • High electrochemical performances were demonstrated

  17. Anchoring FRP Composite Armor in Flexible Offshore Riser Systems

    Costache, Andrei

    things, they serve for the transportation of hydrocarbons from the subsea facilities to the production and drilling equipment at the sea surface. Flexible risers are the prime choice for connecting floating production, storage and offloading facilities, because they are specially designed for dynamic...... counterpart. A new double grip design with flat faces is proposed, in which the loads are transferred through friction. The behavior of such grip is studied by means of experimental testing and finite element modeling. Several iterations of the grip system were evaluated over the course of the project...

  18. Removal of Cu 2+ Ions from Aqueous Medium Using Clinoptilolite/Emeraldine Base Composite

    Silviya I. Lavrova

    2016-12-01

    Full Text Available The aim of this study was to investigate the removal efficiency of in situ synthesized composites consisted of emeraldine base and clinoptilolite on copper ions removal from aqueous medium. Two composite materials (Composite I and Composite II with different quantity of clinoptilolite were synthesised. The influence of the composite dosage, the contact time and the initial copper ions concentration has been studied. The results show that the significant removal of the copper ions becomes at the first minute of the contact between the composite material and the aqueous medium and the longer contact time leads to increasing of the copper ions removal. The removal efficiency at the 1st minute was 57.5% and 77.3% using Composite Iand Composite II, respectively. Maximum removal efficiency of 87.3% and 96.8% was achieved at the same dosage of Composite I and Composite II, respectively, at contact time of 360 minutes and temperature of 24 °C.

  19. Enhanced adsorptive degradation of Congo red in aqueous solutions using polyaniline/Fe0 composite nanofibers

    Bhaumik, M

    2015-01-01

    Full Text Available In this study, a simple approach was described for the fabrication of composite nanofibers (CNFs) of polyaniline/Fe0 (PANI/Fe0) using a template-free method for the reductive degradation and removal of Congo red (CR) from aqueous solutions. The PANI...

  20. Transparent and flexible electrodes and supercapacitors using polyaniline/single-walled carbon nanotube composite thin films

    Ge, Jun; Cheng, Guanghui; Chen, Liwei

    2011-08-01

    Large-scale transparent and flexible electronic devices have been pursued for potential applications such as those in touch sensors and display technologies. These applications require that the power source of these devices must also comply with transparent and flexible features. Here we present transparent and flexible supercapacitors assembled from polyaniline (PANI)/single-walled carbon nanotube (SWNT) composite thin film electrodes. The ultrathin, optically homogeneous and transparent, electrically conducting films of the PANI/SWNT composite show a large specific capacitance due to combined double-layer capacitance and pseudo-capacitance mechanisms. A supercapacitor assembled using electrodes with a SWNT density of 10.0 µg cm-2 and 59 wt% PANI gives a specific capacitance of 55.0 F g-1 at a current density of 2.6 A g-1, showing its possibility for transparent and flexible energy storage.

  1. Composite Sliding Mode Control for a Free-Floating Space Rigid-Flexible Coupling Manipulator System

    Congqing, Wang; Pengfei, Wu; Xin, Zhou; Xiwu, Pei

    2013-01-01

    The flexible space manipulator is a highly nonlinear and coupled dynamic system. This paper proposes a novel composite sliding mode control to deal with the vibration suppression and trajectory tracking of a free-floating space rigid-flexible coupling manipulator with a rigid payload. First, the dynamic equations of this system are established by using Lagrange and assumed mode methods and in the meantime this dynamic modelling allows consideration of the modelling errors, the external distur...

  2. Removal of Congo red dye from aqueous solutions using a halloysite-magnetite-based composite.

    Ferrarini, F; Bonetto, L R; Crespo, Janaina S; Giovanela, M

    2016-01-01

    Adsorption has been considered as one of the most effective methods to remove dyes from aqueous solutions due to its ease of operation, high efficiency and wide adaptability. In view of all these aspects, this study aimed to evaluate the adsorption capacity of a halloysite-magnetite-based composite in the removal of Congo red dye from aqueous solutions. The effects of stirring rate, pH, initial dye concentration and contact time were investigated. The results revealed that the adsorption kinetics followed the pseudo-second-order model, and equilibrium was well represented by the Brunauer-Emmett-Teller isotherm. The thermodynamic data showed that dye adsorption onto the composite was spontaneous and endothermic and occurred by physisorption. Finally, the composite could also be regenerated at least four times by calcination and was shown to be a promising adsorbent for the removal of this dye.

  3. Magnetic composite beads for sorption of cesium ions from aqueous streams

    Shinde, Rakesh N.; Pandey, A.K.; Acharya, R.; Rajurkar, N.S.

    2014-01-01

    Magnetic separation of metal ions is one of the promising methods due to simple, fast, efficient and cost effective technology. Highly selective magnetic sorbents can be designed by immobilizing functional groups in magnetic carrier which binds to the target specific ions. In the present work chitosan-(3-aminopropyl) triethoxysilane (APTS)- copperferrocyanide (CFC) composite beads have been synthesized for sorption of 137 Cs ions from aqueous streams. Physical characterization of the best resulted polymer beads was carried out by SEM-EDX and VSM technique. Sorption of Cs ions in the various magnetic polymer beads were studied in different aqueous condition by 137 Cs (662 KeV) radiotracer assay

  4. Carbon/Sulfur Composite Cathodes for Flexible Lithium/Sulfur Batteries: Status and Prospects

    Zhao, Yan; Zhang, Yongguang; Bakenova, Zagipa; Bakenov, Zhumabay

    2015-01-01

    High specific energy and low cost flexible lithium/sulfur batteries have attracted significant attention as a promising power source to enable future flexible and wearable electronic devices. Here, we review recent progress in the development of free-standing sulfur composite cathodes, with special emphasis on electrode material selectivity and battery structural design. The mini-review is organized based on the dimensionality of different scaffold materials, namely one-dimensional carbon nanotube (CNT), two-dimensional graphene, and three-dimensional CNT/graphene composite, respectively. Finally, the opportunities and perspectives of the future research directions are discussed.

  5. Aqueous Extract Composition of Spent Ginger (Zingiber officinale var. Amarum) from Essential Oil Distillation

    Manuhara, G. J.; Mentari, G. P.; Khasanah, L. U.; Utami, R.

    2018-03-01

    Ginger (Zingiber officinale var Amarum) is widely used as raw material for essential oil production in Indonesia and contain high functional compounds. After producing essential oil, distillation leave less valuable spent ginger. This research was conducted to determine the bioactive compounds remained in aqueous extract of the spent ginger. The extracts were produced at various combination of temperature (55, 75, 95°C) and duration (15, 30, 45 minutes). The extract composition was observed using Gas Chromatography - Mass Spectrometry analysis. The temperature and time of maceration extraction affected the content of compounds in spent ginger aqueous extracts. The extracts contained four largest components of α-curcumene, α-zingiberene, β-sesquiphellandrene and β-bisabolene. The aqueous extracts from spent ginger contained the compounds which may contribute to distinctive flavor of ginger and also bioactive function.

  6. Strong Adhesion of Silver/Polypyrrole Composite onto Plastic Substrates toward Flexible Electronics

    Kawakita, Jin; Hashimoto, Yasuo; Chikyow, Toyohiro

    2013-06-01

    Flexible electronics require sufficient adhesion to substrates, such as a plastic or a polymer, of the electric wiring for devices. A composite of a conducting metal and a polymer is a candidate alternative to pure metals in terms of wire flexibility. The purpose of this study was to evaluate the adhesiveness of a silver/polypyrrole composite to plastic substrates and to clarify the mechanism of adhesion. The composite was prepared on various plastic substrates by dropping its fluid dispersion. Its adhesiveness was evaluated by the peel-off test and its interfacial structure was characterized by microscopy measurements. Some polymers including Teflon with generally weak adhesion to different materials showed a high adhesiveness of more than 90%. The strong adhesion was related to the anchoring effect of the composite penetrating into the pores near the surface of the substrate.

  7. Piezoelectric Lead Zirconium Titanate Composite Touch Sensors for Integration with Flexible OLED Technology

    Deutz, D.B.; Tempelman, E.; Zwaag, S. van der; Groen, W.A.

    2015-01-01

    To enable the design of more intuitive product user interfaces, the prospects of matching piezoelectric touch sensors with flexible organic light emitting diode (OLED) technology are investigated. Low stiffness piezoelectric composite sensors, combining piezoelectric Pb(Zr,Ti)O3 powder with a

  8. Aqueous preparation of polyethylene glycol/sulfonated graphene phase change composite with enhanced thermal performance

    Li, Hairong; Jiang, Ming; Li, Qi; Li, Denian; Chen, Zongyi; Hu, Waping; Huang, Jing; Xu, Xizhe; Dong, Lijie; Xie, Haian; Xiong, Chuanxi

    2013-01-01

    Highlights: • We report an aqueous preparation technique of PEG/graphene phase change composite. • Hydrophilic sulfonated graphene (SG) nanosheets were synthesized. • Large increase in thermal conductivity is attained at low SG loading. • High latent heat is retained due to the low filler loading. • Affinity between SG and PEG contributes to the enhanced thermal performance. - Abstract: A polyethylene glycol (PEG)/sulfonated graphene (SG) phase change composite with enhanced thermal performance was prepared by solution processing in aqueous medium. It is remarkable that the addition of only 4 wt.% of SG to PEG could lead to a four times higher increase in thermal conductivity and a slight decrease in the phase change enthalpy, which is attributed to the formation of efficient thermal conductive network within the PEG matrix relevant to the excellent thermal property and unique 2-dimensional morphology of graphene as well as strong interface affinity between PEG matrix and SG nanosheets. The aqueous preparation technique is expected to pioneer a new way to prepare environment friendly organic phase change materials, and the production of PEG/SG composites is potentially scalable due to the facile fabricating process

  9. Characteristics of regenerated nanocellulosic fibers from cellulose dissolution in aqueous solutions for wood fiber/polypropylene composites

    Sangyeob Lee; Hui Pan; Chung Y. Hse; Alfred R. Gunasekaran; Todd F. Shupe

    2014-01-01

    The effects of aqueous solutions were evaluated on the properties of regenerated cellulosic nanofibers prepared from pure cellulose fibers in various formulations of aqueous solutions. Thermoplastic composites were prepared with reinforcement of the regenerated cellulosic nanofibers. The regenerated cellulosic fibers from cellulosic woody biomass were obtained from...

  10. Optimization of strontium adsorption from aqueous solution using (mn-Zr) oxide-pan composite spheres

    Inan, S.; Altas, Y.

    2009-01-01

    The processes based on adsorption and ion exchange have a great role for the pre-concentration and separation of toxic, long lived radionuclides from liquid waste. In Nuclear waste management, the removal of long lived, radiotoxic isotopes from radioactive waste such as strontium reduces the storage problems and facilitates the disposal of the waste. Depending on the waste type, a variety of adsorbents and/or ion exchangers are used. Due to the amorphous structure of hydrous oxides and their mixtures, they don't have reproducible properties. Besides, obtained powders are very fine particles and they can cause operational problems such as pressure drop and filtration. Therefore they are not suitable for column applications. These reasons have recently expedited the study on the preparation of organic-inorganic composite adsorbent beads for industrial applications. PAN, as a stable and porous support for fine particles, provides the utilization of ion exchangers in large scale column applications. The utilization of PAN as a support material with many inorganic ion exchangers was firstly achieved by Sebesta in the beginning of 1990's. Later on, PAN based composite ion exchangers were prepared and used for the removal of radionuclides and heavy metal ions from aqueous solution and waste waters. In this study, spherical (Mn-Zr)oxide-PAN composite were prepared for separation of strontium from aqueous solution in a wide pH range. Sr 2 + adsorption of composite adsorbent was optimized by using experimental design 'Central Composite Design' model.

  11. Influence of Zircaloy cladding composition on hydride formation during aqueous hydrogen charging

    Rajasekhara, S. [Intel Corporation, 2501 NW 229th Av., Hillsboro, OR 97124 (United States); Kotula, P.G.; Enos, D.G.; Doyle, B.L. [Sandia National Laboratories, Albuquerque, NM, 87185 (United States); Clark, B.G., E-mail: blyclar@sandia.gov [Sandia National Laboratories, Albuquerque, NM, 87185 (United States)

    2017-06-15

    Although hydrogen uptake in Zirconium (Zr) based claddings has been a topic of many studies, hydrogen uptake as a function of alloy composition has received little attention. In this work, commercial Zr-based cladding alloys (Zircaloy-2, Zircaloy-4 and ZIRLO™), differing in composition but with similar initial textures, grain sizes, and surface roughness, were aqueously charged with hydrogen for 100, 300, and 1000 s at nominally 90 °C to produce hydride layers of varying thicknesses. Transmission electron microscope characterization following aqueous charging showed hydride phase and orientation relationship were identical in all three alloys. However, elastic recoil detection measurements confirmed that surface hydride layers in Zircaloy-2 and Zircaloy-4 were an order of magnitude thicker relative to ZIRLO™. - Highlights: •Aqueous charging was performed to produce a layer of zirconium hydride for three different Zr-alloy claddings. •Hydride thicknesses were analyzed by elastic recoil detection and transmission electron microscopy. •Zircaloy-2 and Zircaloy-4 formed thicker hydride layers than ZIRLO™ for the same charging durations.

  12. Processing of high performance composites based on peek by aqueous suspension prepregging

    Liliana Burakowski Nohara

    2010-06-01

    Full Text Available The use of polyamic acid (PAA precursor as interphase in polymer composites is one of the many applications of polyimides (PIs. In this work, composites based on poly(ether-ether-ketone (PEEK and carbon fibers were prepared using two manufacturing techniques for thermoplastic composites: hot compression molding, and aqueous polymeric suspension prepregging using PIs as interphase. Two PAAs were synthesized and used as interphases: 3,3'-4,4'-benzophenonetetracarboxylic dianhydride/oxydianiline (BTDA/ODA and pyromellitic dianhydride/oxydianiline (PMDA/ODA. The PAA/PI systems were analyzed by differential scanning calorimetry (DSC, thermogravimetry (TGA, Fourier transform infrared spectroscopy (FTIR and nuclear magnetic resonance (NMR. Results from these analyses confirmed the synthesis of these compounds. Aqueous polymeric suspension prepregging was more efficient than hot compression molding when the PMDA/ODA PAA/PI interphase was used; also, the interlaminar shear strength of composites produced using this technique was 14.5% higher than the one produced using hot compression molding.

  13. Lignocellulosic Composites Prepared Utilizing Aqueous Alkaline/Urea Solutions with Cold Temperatures

    Brent Tisserat

    2018-01-01

    Full Text Available Lignocellulosic composites (LCs were fabricated by partially dissolving cotton to create a matrix that was reinforced with osage orange wood (OOW particles and/or blue agave fibers (AF. LCs were composed of 15–35% cotton matrix and 65–85% OWW/AF reinforcement. The matrix was produced by soaking cotton wool in a cold aqueous alkaline/urea solvent and was stirred for 15 minutes at 350 rpm to create a viscous gel. The gel was then reinforced with lignocellulosic components, mixed, and then pressed into a panel mold. LC panels were soaked in water to remove the aqueous solvent and then oven dried to obtain the final LC product. Several factors involved in the preparation of these LCs were examined including reaction temperatures (−5 to −15°C, matrix concentration (15–35% cotton, aqueous solvent volume (45–105 ml/panel, and the effectiveness of employing various aqueous solvent formulations. The mechanical properties of LCs were determined and reported. Conversion of the cotton into a suitable viscous gel was critical in order to obtain LCs that exhibited high mechanical properties. LCs with the highest mechanical properties were obtained when the cotton wools were subjected to a 4.6% LiOH/15% urea solvent at −12.5°C using an aqueous solvent volume of 60 ml/panel. Cotton wool subjected to excessive cold alkaline solvents volumes resulted in irreversible cellulose breakdown and a resultant LC that exhibited poor mechanical properties.

  14. Synthesis of a magnetic composite resin and its cobalt removal characteristics in aqueous solution

    Kim, Young Kyun; Lee, Kun Jai

    2001-01-01

    A series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenolsulphonic-formaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. The ion exchange and sorption characteristics of the composite resin prepared by the above method at various conditions were experimentally disclosed. The composite resin prepared shows stably high removal efficiency to Co(II) species in aqueous solution in a wide range of solution pH. The overall isotherm is qualitatively explained by the generalized adsorption isotherm concept proposed by McKinley. The standard enthalpy change derived from van't Hoff equation conforms to the typical range for chemisorption or ion exchange. The selectivity of the PSF-F (phenolsulphonic formaldehyde-iron ferrite) composite resin to Co(II) species and other competing chemicals (i.e. Na 2 EDTA, Ca(II) and Na) was compared. It is anticipated that the composite resin can also be used for column-operation with process-control by applying external magnetic field, since the rigid bead-type composite resin shows magnetic-susceptibility due to its paramagnetic inorganic constituent (i.e. iron ferrite). (author)

  15. Hybrid Composite Tensile Armour Wires in Flexible Risers: A Multi-scale Model

    Gautam, Mayank; Katnam, Kali-Babu; Potluri, Venkata; Jha, Vivekanand; Latto, J.; Dodds, NI

    2017-01-01

    Traditional carbon-steel armour wires pose limitations (e.g. long spans, weight reduction, corrosion and fatigue) for flexible risers to operate in demanding and deeper water environments. In this context, an alternative to carbon-steel tensile armour wires is proposed recently by the authors (Gautam et al. [1]), comprising of hexagonally packed polymer composite rods with uni-directional fibres and an over-braided (i.e. bi-axial braid with high performance fibres) sleeve. These hybrid compos...

  16. Bioinspired Flexible and Highly Responsive Dual-Mode Strain/Magnetism Composite Sensor.

    Huang, Pei; Li, Yuan-Qing; Yu, Xiao-Guang; Zhu, Wei-Bin; Nie, Shu-Yan; Zhang, Hao; Liu, Jin-Rui; Hu, Ning; Fu, Shao-Yun

    2018-04-04

    The mimicry of human skin to detect both oncoming and physical-contacting object is of great importance in the fields of manufacturing, artificial robots and vehicles, etc. Herein, a novel bioinspired flexible and highly responsive dual-mode strain/magnetism composite sensor, which works via both contact and contactless modes, is first fabricated by incorporating Fe 3 O 4 /silicone system into a carbon fiber aerogel (CFA). The distance dependence of magnetic field endorses the CFA/Fe 3 O 4 /silicone composite possible for spatial sensing due to the introduction of Fe 3 O 4 magnetic nanoparticles. As a result, the as-prepared flexible sensor exhibits precise and real-time response not only to direct-contact compression as usual but also to contactless magnetic field in a wide frequency range from 0.1 to 10 Hz, achieving the maximum variance of 68% and 86% in relative electrical resistance, respectively. The contact and contactless sensing modes of the strain/magnetism sensor are clearly demonstrated by recording the speeds of bicycle riding and walking, respectively. Interestingly, this dual-mode composite sensor exhibits the capacity of identifying the contact and contactless state, which is the first report for flexible sensors. The current protocol is eco-friendly, facile, and thought-provoking for the fabrication of multifunctional sensors.

  17. Polyvinylpyrrolidone/polyvinyl butyral composite as a stable binder for castable supercapacitor electrodes in aqueous electrolytes

    Aslan, M.; Weingarth, D.; Herbeck-Engel, P.; Grobelsek, I.; Presser, V.

    2015-04-01

    Mixtures of polyvinylpyrrolidone/polyvinyl butyral (PVP/PVB) are attractive binders for the preparation of carbon electrodes for aqueous electrolyte supercapacitors. The use of PVP/PVB offers several key advantages: They are soluble in ethanol and can be used to spray coat or drain cast activated carbon (AC) electrodes directly on a current collector. Infrared spectroscopy and contact angle measurements show that the PVP-to-PVB ratio determines the degree of binder hydrophilicity. Within our study, the most favorable performance was obtained for AC electrodes with a composition of AC + 1.5 mass% PVP + 6.0 mass% PVB; such electrodes were mechanically stabile and water resistant with a PVP release of less than 5% of total PVP while PVB itself is water insoluble. Compared to when using PVDF, the specific surface area (SSA) of the assembled electrodes was 10% higher, indicating a reduced pore blocking tendency. A good electrochemical performance was observed in different aqueous electrolytes for composite electrodes with the optimized binder composition: 160 F g-1 at 1 A g-1 for 1 M H2SO4 and 6 M KOH and 120 F g-1 for 1 M NaCl. The capacitance was slightly reduced by 2.5% after cycling to 1.2 V with 1.28 A g-1 in 1 M NaCl for 10,000 times.

  18. Adsorption of methyl orange from aqueous solution using chitosan/diatomite composite.

    Zhao, Peng; Zhang, Runhu; Wang, Jianglin

    2017-04-01

    A novel chitosan/diatomite composite was prepared by a simple mixture in the mass ratio to remove methyl orange (MO) from aqueous media in this study. The composite adsorbent was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy analysis. The parameters to influence the adsorption of MO were studied under such conditions as kinetics, adsorption isotherm, pH effect, and thermodynamics. The results revealed that adsorption of MO was initially rapid and the equilibrium time was reached after 40 min. The optimal value of the pH was 5.0 for better adsorption. The equilibrium data were well fitted to the Langmuir isotherm compared to the Freundlich isotherm, and exhibited the highest capacity and a removal rate of 88.37% under an initial dye concentration of 50 mg/L. The kinetic data were well described by the pseudo-second order model. The thermodynamic calculations revealed that the sorption was viable, spontaneous, and exothermic under the conditions studied. In addition, the chitosan/diatomite composite had good adsorption and desorption performance with respect to reusability after six cycles. These results showed that the chitosan/diatomite could be considered as a potential adsorbent for the removal of MO in aqueous solution.

  19. Pyrene As a New Detector for Determining the Composition of Silver Nanoparticle Dispersions in Aqueous Solutions

    Romanovskaya, G. I.; Kazakova, S. Yu.; Koroleva, M. V.; Zuev, B. K.

    2018-03-01

    It is proposed that the fluorescence of monomeric molecules of pyrene in solid matrices or in concentrated micellar solutions be used as a detector for determining the compositional homogeneity of silver nanoparticle (NP) dispersions in aqueous solutions synthesized in different ways. It is found that the morphology of silver NPs affects the change in the fluorescence intensity of monomeric molecules of pyrene in a certain (violet or blue) region of the pyrene optical spectrum. The observed phenomenon is attributed to the resonance of electronic transitions in the monomeric molecules of pyrene in regions with plasmon oscillations in silver nanoparticles. A new way of obtaining fluorescent silver NPs is found.

  20. 3D flexible NiTi-braided elastomer composites for smart structure applications

    Heller, L; Vokoun, D; Šittner, P; Finckh, H

    2012-01-01

    While outstanding functional properties of thin NiTi wires are nowadays well recognized and beneficially utilized in medical NiTi devices, development of 2D/3D wire structures made out of these NiTi wires remains challenging and mostly unexplored. The research is driven by the idea of creating novel 2D/3D smart structures which inherit the functional properties of NiTi wires and actively utilize geometrical deformations within the structure to create new/improved functional properties. Generally, textile technology provides attractive processing methods for manufacturing 2D/3D smart structures made out of NiTi wires. Such structures may be beneficially combined with soft elastomers to create smart deformable composites. Following this route, we carried out experimental work focused on development of 3D flexible NiTi-braided elastomer composites involving their design, laboratory manufacture and thermomechanical testing. We describe the manufacturing technology and structural properties of these composites; and perform thermomechanical tests on the composites, focusing particularly on quasistatic tensile properties, energy absorption, damping and actuation under tensile loading. Functional thermomechanical properties of the composites are discussed with regard to the mechanical properties of the components and architecture of the composites. It is found that the composites indeed inherit all important features of the thermomechanical behavior of NiTi wires but, due to their internal architecture, outperform single NiTi wires in some features such as the magnitude of recoverable strain, superelastic damping capacity and thermally induced actuation strain. (paper)

  1. Electrically Conductive TPU Nanofibrous Composite with High Stretchability for Flexible Strain Sensor

    Tong, Lu; Wang, Xiao-Xiong; He, Xiao-Xiao; Nie, Guang-Di; Zhang, Jun; Zhang, Bin; Guo, Wen-Zhe; Long, Yun-Ze

    2018-03-01

    Highly stretchable and electrically conductive thermoplastic polyurethane (TPU) nanofibrous composite based on electrospinning for flexible strain sensor and stretchable conductor has been fabricated via in situ polymerization of polyaniline (PANI) on TPU nanofibrous membrane. The PANI/TPU membrane-based sensor could detect a strain from 0 to 160% with fast response and excellent stability. Meanwhile, the TPU composite has good stability and durability. Besides, the composite could be adapted to various non-flat working environments and could maintain opportune conductivity at different operating temperatures. This work provides an easy operating and low-cost method to fabricate highly stretchable and electrically conductive nanofibrous membrane, which could be applied to detect quick and tiny human actions.

  2. Optimizing the surfactant for the aqueous processing of LiFePO{sub 4} composite electrodes

    Porcher, W.; Jouanneau, S. [Commissariat a l' Energie Atomique, 38054 Grenoble Cedex 9 (France); Lestriez, B.; Guyomard, D. [Institut des Materiaux Jean Rouxel (IMN), Universite de Nantes, CNRS, 44322 Nantes Cedex 3 (France)

    2010-05-01

    Aqueous processing would reduce the costs associated with the making of the composite electrode. To achieve the incorporation and the dispersion of the carbon black (CB) conductive agent in aqueous slurries, a surfactant is needed. In this paper, three surfactants are compared, an anionic one, the sodium dodecyle sulphate (SDS), a non-ionic one, the isooctylphenylether of polyoxyethylene called commercially Triton X-100 and a cationic one, the hexadecyltrimethylammonium bromide (CTAB), by using rheology and laser granulometry measurements on electrode slurries on one hand, and SEM observations, porosity and adhesion measurements and electrochemical testing on composite electrodes on the other hand. Ionic surfactants were found to be not suitable because a corrosion of the aluminium current collector occurred. The utilization of Triton X-100 favoured a more homogeneous CB distribution, resulted in a better electronic wiring of the active material particles and higher rate behavior of the electrode. Optimal electrochemical performances are obtained for an optimal surfactant concentration which depends on the BET surface area of the CB powder. (author)

  3. Effect of liquid oil additive on lithium-ion battery ceramic composite separator prepared with an aqueous coating solution

    Kim, Sang Woo [Division of Advanced Materials Engineering, Kongju National University, 1223–24, Cheonan-daero, Cheonan, Chungnam, 31080 (Korea, Republic of); Ryou, Myung-Hyun [Department of Chemical & Biological Engineering, Hanbat National University, 125, Dongseodaero, Yuseong-gu, Daejeon, 34158 (Korea, Republic of); Lee, Yong Min, E-mail: yongmin.lee@hanbat.ac.kr [Department of Chemical & Biological Engineering, Hanbat National University, 125, Dongseodaero, Yuseong-gu, Daejeon, 34158 (Korea, Republic of); Cho, Kuk Young, E-mail: kycho@hanyang.ac.kr [Department of Materials Science and Chemical Engineering, Hanyang University, 55, Hanyangdaehak-ro, Sangrok-gu, Ansan, Gyeonggi-do, 15588 (Korea, Republic of)

    2016-08-05

    Ceramic composite separators (CCSs) play a critical role in ensuring safety for lithium-ion batteries (LIBs), especially for mid- and large-sized devices. However, production of CCSs using organic solvents has some cost and environmental concerns. An aqueous process for fabricating CCSs is attractive because of its cost-effectiveness and environmental-friendliness because organic solvents are not used. The success of an aqueous coating system for LIBs is dependent upon minimizing moisture content, as moisture has a negatively impact on LIB performance. In this study, CCSs were fabricated using an aqueous coating solution containing Al{sub 2}O{sub 3} and an acrylic binder. Compared with polyethylene (PE) separators, CCSs coated with an aqueous coating solution showed improved thermal stability, electrolyte uptake, puncture strength, ionic conductivity, and rate capability. In addition, our new approach of introducing a small amount of an oily liquid to the aqueous coating solution reduced the water adsorption by 11.7% compared with coatings that do not contain the oily liquid additive. - Highlights: • Ceramic composite separator is fabricated using aqueous coating process. • Coated separator showed enhanced mechanical and thermal stability. • Liquid oil additive in coating solution reduce moisture reabsorption of separator. • Oil additive in aqueous coating solution does not deteriorate LIB performance.

  4. Flexible ITO-free organic solar cells applying aqueous solution-processed V2O5 hole transport layer: An outdoor stability study

    F. Anderson S. Lima

    2016-02-01

    Full Text Available Solution processable semiconductor oxides have opened a new paradigm for the enhancement of the lifetime of thin film solar cells. Their fabrication by low-cost and environmentally friendly solution-processable methods makes them ideal barrier (hole and electron transport layers. In this work, we fabricate flexible ITO-free organic solar cells (OPV by printing methods applying an aqueous solution-processed V2O5 as the hole transport layer (HTL and compared them to devices applying PEDOT:PSS. The transparent conducting electrode was PET/Ag/PEDOT/ZnO, and the OPV configuration was PET/Ag/PEDOT/ZnO/P3HT:PC60BM/HTL/Ag. Outdoor stability analyses carried out for more than 900 h revealed higher stability for devices fabricated with the aqueous solution-processed V2O5.

  5. Composite flexible skin with large negative Poisson’s ratio range: numerical and experimental analysis

    Chen, Y. J.; Scarpa, F.; Farrow, I. R.; Liu, Y. J.; Leng, J. S.

    2013-04-01

    This paper describes the manufacturing, characterization and parametric modeling of a novel fiber-reinforced composite flexible skin with in-plane negative Poisson’s ratio (auxetic) behavior. The elastic mechanical performance of the auxetic skin is evaluated using a three-dimensional analytical model based on the classical laminate theory (CLT) and Sun’s thick laminate theory. Good agreement is observed between in-plane Poisson’s ratios and Young’s moduli of the composite skin obtained by the theoretical model and the experimental results. A parametric analysis carried out with the validated model shows that significant changes in the in-plane negative Poisson’s ratio can be achieved through different combinations of matrix and fiber materials and stacking sequences. It is also possible to identify fiber-reinforced composite skin configurations with the same in-plane auxeticity but different orthotropic stiffness performance, or the same orthotropic stiffness performance but different in-plane auxeticity. The analysis presented in this work provides useful guidelines to develop and manufacture flexible skins with negative Poisson’s ratio for applications focused on morphing aircraft wing designs.

  6. Composite flexible skin with large negative Poisson’s ratio range: numerical and experimental analysis

    Chen, Y J; Leng, J S; Scarpa, F; Farrow, I R; Liu, Y J

    2013-01-01

    This paper describes the manufacturing, characterization and parametric modeling of a novel fiber-reinforced composite flexible skin with in-plane negative Poisson’s ratio (auxetic) behavior. The elastic mechanical performance of the auxetic skin is evaluated using a three-dimensional analytical model based on the classical laminate theory (CLT) and Sun’s thick laminate theory. Good agreement is observed between in-plane Poisson’s ratios and Young’s moduli of the composite skin obtained by the theoretical model and the experimental results. A parametric analysis carried out with the validated model shows that significant changes in the in-plane negative Poisson’s ratio can be achieved through different combinations of matrix and fiber materials and stacking sequences. It is also possible to identify fiber-reinforced composite skin configurations with the same in-plane auxeticity but different orthotropic stiffness performance, or the same orthotropic stiffness performance but different in-plane auxeticity. The analysis presented in this work provides useful guidelines to develop and manufacture flexible skins with negative Poisson’s ratio for applications focused on morphing aircraft wing designs. (paper)

  7. Nanotube liquid crystal elastomers: photomechanical response and flexible energy conversion of layered polymer composites

    Fan, Xiaoming; King, Benjamin C; Loomis, James; Panchapakesan, Balaji; Campo, Eva M; Hegseth, John; Cohn, Robert W; Terentjev, Eugene

    2014-01-01

    Elastomeric composites based on nanotube liquid crystals (LCs) that preserve the internal orientation of nanotubes could lead to anisotropic physical properties and flexible energy conversion. Using a simple vacuum filtration technique of fabricating nanotube LC films and utilizing a transfer process to poly (dimethyl) siloxane wherein the LC arrangement is preserved, here we demonstrate unique and reversible photomechanical response of this layered composite to excitation by near infra-red (NIR) light at ultra-low nanotube mass fractions. On excitation by NIR photons, with application of small or large pre-strains, significant expansion or contraction of the sample occurs, respectively, that is continuously reversible and three orders of magnitude larger than in pristine polymer. Schlieren textures were noted in these LC composites confirming long range macroscopic nematic order of nanotubes within the composites. Order parameters of LC films ranged from S optical  = 0.51–0.58 from dichroic measurements. Film concentrations, elastic modulus and photomechanical stress were all seen to be related to the nematic order parameter. For the same nanotube concentration, the photomechanical stress was almost three times larger for the self-assembled LC nanotube actuator compared to actuator based on randomly oriented carbon nanotubes. Investigation into the kinetics of photomechanical actuation showed variation in stretching exponent β with pre-strains, concentration and orientation of nanotubes. Maximum photomechanical stress of ∼0.5 MPa W −1 and energy conversion of ∼0.0045% was achieved for these layered composites. The combination of properties, namely, optical anisotropy, reversible mechanical response to NIR excitation and flexible energy conversion all in one system accompanied with low cost makes nanotube LC elastomers important for soft photochromic actuation, energy conversion and photo-origami applications. (paper)

  8. Preparation of smooth, flexible and stable silver nanowires- polyurethane composite transparent conductive films by transfer method

    Bai, Shengchi; Wang, Haifeng; Yang, Hui; Zhang, He; Guo, Xingzhong

    2018-02-01

    Silver nanowires (AgNWs)-polyurethane (PU) composite transparent conductive films were fabricated via transfer method using AgNWs conductive inks and polyurethane as starting materials, and the effects of post-treatments including heat treatment, NaCl solution bath and HCl solution bath for AgNWs film on the sheet resistance and transmittance of the composite films were respectively investigated in detail. AgNWs networks are uniformly embedded in the PU layer to improve the adhesion and reduce the surface roughness of AgNWs-PU composite films. Heat treatment can melt and weld the nanowires, and NaCl and HCl solution baths promote the dissolution and re-deposition of silver and the dissolving of the polymer, both which form conduction pathways and improve contact of AgNWs for reducing the sheet resistance. Smooth and flexible AgNWs-PU composite film with a transmittance of 85% and a sheet resistance of 15 Ω · sq‑1 is obtained after treated in 0.5 wt% HCl solution bath for 60 s, and the optoelectronic properties of the resultant composite film can maintain after 1000 cycles of bending and 100 days.

  9. Feature Size Effect on Formability of Multilayer Metal Composite Sheets under Microscale Laser Flexible Forming

    Huixia Liu

    2017-07-01

    Full Text Available Multilayer metal composite sheets possess superior properties to monolithic metal sheets, and formability is different from monolithic metal sheets. In this research, the feature size effect on formability of multilayer metal composite sheets under microscale laser flexible forming was studied by experiment. Two-layer copper/nickel composite sheets were selected as experimental materials. Five types of micro molds with different diameters were utilized. The formability of materials was evaluated by forming depth, thickness thinning, surface quality, and micro-hardness distribution. The research results showed that the formability of two-layer copper/nickel composite sheets was strongly influenced by feature size. With feature size increasing, the effect of layer stacking sequence on forming depth, thickness thinning ratio, and surface roughness became increasingly larger. However, the normalized forming depth, thickness thinning ratio, surface roughness, and micro-hardness of the formed components under the same layer stacking sequence first increased and then decreased with increasing feature size. The deformation behavior of copper/nickel composite sheets was determined by the external layer. The deformation extent was larger when the copper layer was set as the external layer.

  10. Electrochemical characteristics of flexible micro supercapacitors with reduced graphene oxide-carbon nanotubes composite electrodes

    Yang, Kyungwhan; Cho, Kyoungah; Kim, Sangsig

    2018-06-01

    In this study, we fabricate solid-state flexible micro-supercapacitors (MSCs) with reduced graphene oxide-carbon nanotube (rGO-CNT) composite electrodes and investigate the electrochemical characteristics by comparing with those of an MSC with rGO electrodes. Regarding the resistance-capacitance time constant and IR drop, the addition of CNTs into the rGO electrodes shows a significant effect owing to both the decrease in the resistance and the increase in the permeability of the electrolytes. Compared to the rGO MSCs, the rGO-CNT MSCs show an excellent areal capacitance of 2.6 mF/cm2, a smaller IR drop of 11 mV, a lower RC time constant of 6 ms, and faster charging/discharging rates with a high scan rate ability up to 100 V/s. The mechanical stability of the flexible rGO-CNT MSCs is verified by 1000 bending cycles. In addition, the electrochemical characteristics of the flexible rGO-CNT MSCs are maintained regardless of the MSC array type.

  11. Transparent and flexible quantum dot-polymer composites using an ionic liquid as compatible polymerization medium

    Woelfle, Caroline; Claus, Richard O

    2007-01-01

    Quantum dot (QD)-polymer composites were fabricated based on a solution of QDs dispersed in an ionic liquid. Positively charged water-soluble nanocrystals were obtained from solutions of CdSe/ZnS QDs dispersed in toluene by ligand exchange with 2-dimethylaminoethanethiol (DAET). The resulting QDs were further transferred into a hydrophobic ionic liquid HMITFSI (1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) by cation exchange, resulting in a CdSe/ZnS-HMITFSI solution, which was used as a compatible medium for the polymerization and cross-linking of polymethyl methacrylate networks. Transparent, fluorescent and flexible materials resulted. The quantum yields of the composites depended on the initial properties of the QDs dispersed in toluene, and medium-size QDs (2.6 nm) resulted in the highest quantum yields

  12. Electrochemical studies on nanometal oxide-activated carbon composite electrodes for aqueous supercapacitors

    Ho, Mui Yen; Khiew, Poi Sim; Isa, Dino; Chiu, Wee Siong

    2014-11-01

    In present study, the electrochemical performance of eco-friendly and cost-effective titanium oxide (TiO2)-based and zinc oxide-based nanocomposite electrodes were studied in neutral aqueous Na2SO3 electrolyte, respectively. The electrochemical properties of these composite electrodes were studied using cyclic voltammetry (CV), galvanostatic charge-discharge (CD) and electrochemical impedance spectroscopy (EIS). The experimental results reveal that these two nanocomposite electrodes achieve the highest specific capacitance at fairly low oxide loading onto activated carbon (AC) electrodes, respectively. Considerable enhancement of the electrochemical properties of TiO2/AC and ZnO/AC nanocomposite electrodes is achieved via synergistic effects contributed from the nanostructured metal oxides and the high surface area mesoporous AC. Cations and anions from metal oxides and aqueous electrolyte such as Ti4+, Zn2+, Na+ and SO32- can occupy some pores within the high-surface-area AC electrodes, forming the electric double layer at the electrode-electrolyte interface. Additionally, both TiO2 and ZnO nanoparticles can provide favourable surface adsorption sites for SO32- anions which subsequently facilitate the faradaic processes for pseudocapacitive effect. These two systems provide the low cost material electrodes and the low environmental impact electrolyte which offer the increased charge storage without compromising charge storage kinetics.

  13. A vanadium-doped ZnO nanosheets-polymer composite for flexible piezoelectric nanogenerators

    Shin, Sung-Ho; Kwon, Yang Hyeog; Lee, Min Hyung; Jung, Joo-Yun; Seol, Jae Hun; Nah, Junghyo

    2016-01-01

    We report high performance flexible piezoelectric nanogenerators (PENGs) by employing vanadium (V)-doped ZnO nanosheets (NSs) and the polydimethylsiloxane (PDMS) composite structure. The V-doped ZnO NSs were synthesized to overcome the inherently low piezoelectric properties of intrinsic ZnO. Ferroelectric phase transition induced in the V-doped ZnO NSs contributed to significantly improve the performance of the PENGs after the poling process. Consequently, the PENGs exhibited high output voltage and current up to ~32 V and ~6.2 μA, respectively, under the applied strain, which are sufficient to directly turn on a number of light emitting diodes (LEDs). The composite approach for PENG fabrication is scalable, robust, and reproducible during periodic bending/releasing over extended cycles. The approach introduced here extends the performance limits of ZnO-based PENGs and demonstrates their potential as energy harvesting devices.We report high performance flexible piezoelectric nanogenerators (PENGs) by employing vanadium (V)-doped ZnO nanosheets (NSs) and the polydimethylsiloxane (PDMS) composite structure. The V-doped ZnO NSs were synthesized to overcome the inherently low piezoelectric properties of intrinsic ZnO. Ferroelectric phase transition induced in the V-doped ZnO NSs contributed to significantly improve the performance of the PENGs after the poling process. Consequently, the PENGs exhibited high output voltage and current up to ~32 V and ~6.2 μA, respectively, under the applied strain, which are sufficient to directly turn on a number of light emitting diodes (LEDs). The composite approach for PENG fabrication is scalable, robust, and reproducible during periodic bending/releasing over extended cycles. The approach introduced here extends the performance limits of ZnO-based PENGs and demonstrates their potential as energy harvesting devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07185b

  14. Cross-linked PAN-based thin-film composite membranes for non-aqueous nanofiltration

    Pérez-Manríquez, Liliana

    2015-01-01

    A new approach on the development of cross-linked PAN based thin film composite (TFC) membranes for non-aqueous application is presented in this work. Polypropylene backed neat PAN membranes fabricated by phase inversion process were cross-linked with hydrazine to get excellent solvent stability toward dimethylformamide (DMF). By interfacial polymerization a selective polyamide active layer was coated over the cross-linked PAN using N,N′-diamino piperazine (DAP) and trimesoyl chloride (TMC) as monomers. Permeation and molecular weight cut off (MWCO) experiments using various dyes were done to evaluate the performance of the membranes. Membranes developed by such method show excellent solvent stability toward DMF with a permeance of 1.7 L/m2 h bar and a molecular weight cut-off of less than 600 Da.

  15. Aqueous sulfomethylated melamine gel-forming compositions and methods of use

    Meltz, C.N.; Guetzmacher, G.D.; Chang, P.W.

    1989-04-18

    A method is described for the selective modification of the permeability of the strata of a subterranean bydrocarbon-containing reservoir consisting of introducing into a well in, communication with the reservoir; an aqueous gel-forming composition, comprising a 1.0-60.0 weight percent sulfomethylated melamine polymer solution. The solution is prepared with a 1.0 molar equivalent of a malemine, reacted with 3.0-6.7 molar equivalents of formaldehyde or a 2-6 carbon atom containing dialdehyde; 0.25-1.25 molar equivalents of an alkali metal or ammonium salt of surfurous acid; and 0.01-1.5 molar equivalents of a gel-modifying agent.

  16. Equilibrium Adsorption of heavy Metals from Aqueous Solutions onto Poly aniline Stannic(IV) Phosphate Composite

    El-Zahhar, A.A.; EI-Shourbagy, M.M.; Shady, S.A.

    2012-01-01

    An adsorbent material has been prepared by immobilization of stannic(IV) phosphate within poly aniline composite. The produced adsorbent exhibit a high adsorption potential for Pb(II), Cd(Il) and Zn(lI) from aqueous solutions. The influence of initial metal ion concentration, adsorbent dose, ph and temperature on metal ion removal has been studied. The process was found to follow a first order rate kinetics. Thc intra-particle diffusion of metal ions through pores in the adsorbent was to be the main rate limiting step. The equilibrium data fit well with Langmuir adsorption isotherm model. The selectivity order of the adsorbent towards the metal ions was Pb(Il) > Cd(Il) >Zn(II). The adsorption rate constant and thermodynamic parameters were also given to predict the nature of adsorption

  17. Hydrogel core flexible matrix composite (H-FMC) actuators: theory and preliminary modelling

    Dicker, M P M; Weaver, P M; Bond, I P; Rossiter, J M

    2014-01-01

    The underlying theory of a new actuator concept based on hydrogel core flexible matrix composites (H-FMC) is presented. The key principle that underlines the H-FMC actuator operation is that the three-dimensional swelling of a hydrogel is partially constrained in order to improve the amount of useful work done. The partial constraint is applied to the hydrogel by a flexible matrix composite (FMC) that minimizes the hydrogel's volume expansion while swelling. This constraint serves to maximize the fixed charge density and resulting osmotic pressure, the driving force behind actuation. In addition, for certain FMC fibre orientations the Poisson's ratio of the anisotropic FMC laminate converts previously unused hydrogel swelling in the radial and circumferential directions into useful axial strains. The potential benefit of the H-FMC concept to hydrogel actuator performance is shown through comparison of force–stroke curves and evaluation of improvements in useful actuation work. The model used to achieve this couples chemical and electrical components, represented with the Nernst–Plank and Poisson equations, as well as a linear elastic mechanical material model, encompassing limited geometric nonlinearities. It is found that improvements in useful actuation work in the order of 1500% over bare hydrogel performance are achieved by the H-FMC concept. A parametric study is also undertaken to determine the effect of various FMC design parameters on actuator free strain and blocking stress. A comparison to other actuator concepts is also included. (paper)

  18. Effect of solvent composition on the limiting current of anodic dissolution of tungsten in aqueous-ethanol solutions of alkali

    Konoplyantseva, N.A.; L'vova, L.A.; Davydov, A.D.; AN SSSR, Moscow. Inst. Ehlektrokhimii)

    1987-01-01

    The effect of quantitative composition of solvent on tungsten anodic dissolution in aqueous-ethanol solutions of KOH is studied. It is shown that with an increase in ethanol content in aqueous-ethanol solutions of alkali the limiting current of tungsten anodic dissolution decreases. An increase in KOH concentration in certain limits (in ethanol solutions it is the range between 0.75 and 1.0 M KOH) results in the increase of the limiting current; with further increase in solution concentration the limiting current decreases, which can be related to the change of the limiting stage. An assumption is made that total reaction of tungsten anodic dissolution and the main reasons for the limiting current appearance do not change from aqueous to aqueous-ethanol and ethanol solutions of alkali

  19. [DNA complexes, formed on aqueous phase surfaces: new planar polymeric and composite nanostructures].

    Antipina, M N; Gaĭnutdinov, R V; Rakhnianskaia, A A; Sergeev-Cherenkov, A N; Tolstikhina, A L; Iurova, T V; Kislov, V V; Khomutov, G B

    2003-01-01

    The formation of DNA complexes with Langmuir monolayers of the cationic lipid octadecylamine (ODA) and the new amphiphilic polycation poly-4-vinylpyridine with 16% of cetylpyridinium groups (PVP-16) on the surface of an aqueous solution of native DNA of low ionic strength was studied. Topographic images of Langmuir-Blodgett films of DNA/ODA and DNA/PVP-16 complexes applied to micaceous substrates were investigated by the method of atomic force microscopy. It was found that films of the amphiphilic polycation have an ordered planar polycrystalline structure. The morphology of planar DNA complexes with the amphiphilic cation substantially depended on the incubation time and the phase state of the monolayer on the surface of the aqueous DNA solution. Complex structures and individual DNA molecules were observed on the surface of the amphiphilic monolayer. Along with quasi-linear individual bound DNA molecules, characteristic extended net-like structures and quasi-circular toroidal condensed conformations of planar DNA complexes were detected. Mono- and multilayer films of DNA/PVP-16 complexes were used as templates and nanoreactors for the synthesis of inorganic nanostructures via the binding of metal cations from the solution and subsequent generation of the inorganic phase. As a result, ultrathin polymeric composite films with integrated DNA building blocks and quasi-linear arrays of inorganic semiconductor (CdS) and iron oxide nanoparticles and nanowires were obtained. The nanostructures obtained were characterized by scanning probe microscopy and transmission electron microscopy techniques. The methods developed are promising for investigating the mechanisms of structural organization and transformation in DNA and polyelectrolyte complexes at the gas-liquid interface and for the design of new extremely thin highly ordered planar polymeric and composite materials, films, and coatings with controlled ultrastructure for applications in nanoelectronics and

  20. Flexible nano-GFO/PVDF piezoelectric-polymer nano-composite films for mechanical energy harvesting

    Mishra, Monali; Roy, Amritendu; Dash, Sukalyan; Mukherjee, Somdutta

    2018-03-01

    Owing to the persistent quest of renewable energy technology, piezoelectric energy harvesters are gathering considerable research interest due to their potential in driving microelectronic devices with small power requirement. Electrical energy (milli to microwatt range) is generated from mechanical counterparts such as vibrations of machines, human motion, flowing water etc. based on the principles of piezoelectricity. Flexible high piezoelectric constant (d33) ceramic/polymer composites are crucial components for fabricating these energy harvesters. The polymer composites composed of gallium ferrite nanoparticles and polyvinylidene fluoride (PVDF) as the matrix have been synthesized by solvent casting method. First, 8 wt. % PVDF was dissolved in DMF and then different compositions of GaFeO3 or GFO (10, 20, 30 wt. %) (with respect to PVDF only) nanocomposites were synthesized. The phase of the synthesized nanocomposites were studied by X- Ray diffraction which shows that with the increase in the GFO concentration, the intensity of diffraction peaks of PVDF steadily decreased and GFO peaks became increasingly sharp. As the concentration of GFO increases in the PVDF polymer matrix, band gap is also increased albeit to a small extent. The maximum measured output voltage and current during mechanical pressing and releasing conditions were found to be ~ 3.5 volt and 4 nA, respectively in 30 wt % GFO-PVDF composite, comparable to the available literature.

  1. Electrochemical behavior of nanostructured MnO2/C (Vulcan® composite in aqueous electrolyte LiNO3

    Vujković Milica

    2011-01-01

    Full Text Available The electrolytic solutions of contemporary Li-ion batteries are made exclusively with the organic solvents since anodic materials of these batteries have potentials with greater negativity than the potential of the water reduction, thus the organic electrolytes can withstand the voltages of 3-5 V that are characteristic for these batteries. Ever since it was discovered that some materials can electrochemically intercalate and deintercalate Li+ ions in aqueous solutions, numerous studies have been conducted with the aim of extending operational time of the aqueous Li-ion batteries. Manganese oxide has been studied as the electrode material in rechargeable lithium-ion batteries with organic electrolytes. In this paper its electrochemical behavior as an anode material in aqueous electrolyte solutions was examined. MnO2 as a component of nanodispersed MnO2/C (Vulcan® composite was successfully synthesized hydrothermally. Electrochemical properties of this material were investigated in aqueous saturated LiNO3 solution by both cyclic voltammetry and galvanostatic charging/discharging (LiMn2O4 as cathode material techniques. The obtained composite shows a relatively good initial discharge capacity of 96.5 mAh/g which, after 50th charging/discharging cycles, drops to the value of 57mAh/g. MnO2/C (Vulcan® composite, in combination with LiMn2O4 as a cathode material, shows better discharge capacity compared to other anodic materials used in aqueous Li-ion batteries according to certain studies that have been conducted. Its good reversibility and cyclability, and the fact that hydrothermal method is simple and effective, makes MnO2/C(Vulcan® composite a promising anodic material for aqueous Li-ion batteries.

  2. Preparation and application of attapulgite/iron oxide magnetic composites for the removal of U(VI) from aqueous solution

    Fan, Qiao-hui; Li, Ping; Chen, Yun-fei; Wu, Wang-suo

    2011-01-01

    Highlights: → We first synthesized ATP/IOM composites as an adsorbents for removal U(VI) from aqueous solution. → The sorption ability of ATP/IOM composites were obviously superior to ATP and iron oxides. → The prevalent species of U(VI) on ATP/IOM composites were =S s OUO 2 + and =S w OUO 2 (CO 3 ) 2 3- . → ATP/IOM composites could be a promising candidate for pre-concentration and immobilization of radionuclides from large volumes of aqueous solutions. - Abstract: Recently, magnetic sorbents have received considerable attention because of their excellent segregative features and sorption capacities. Herein, attapulgite/iron oxide magnetic (ATP/IOM) composites were prepared and characterized. The sorption results indicated that ATP/IOM composites were superior to ATP and iron oxides individually for the removal of U(VI) from aqueous solution. Based on X-ray photoelectron spectroscopy (XPS) analysis and surface complexation model, the main sorption species of U(VI) on ATP were =X 2 UO 2 0 below pH 4.0 and =S s OUO 2 + , =S w OUO 2 CO 3 - , and =S w OUO 2 (CO 3 ) 2 3- above pH 5.0. However the prevalent species on ATP/IOM composites were =S s OUO 2 + and =S w OUO 2 (CO 3 ) 2 3- over the observed pH range. ATP/IOM composites are a promising candidate for pre-concentration and immobilization of radionuclides from large volumes of aqueous solutions, as required for remediation purposes.

  3. Vacuum-assisted bilayer PEDOT:PSS/cellulose nanofiber composite film for self-standing, flexible, conductive electrodes.

    Ko, Youngsang; Kim, Dabum; Kim, Ung-Jin; You, Jungmok

    2017-10-01

    Sustainable cellulose nanofiber (CNF)-based composites as functional conductive materials have garnered considerable attention recently for their use in soft electronic devices. In this work, self-standing, highly flexible, and conductive PEDOT:PSS-CNF composite films were developed using a simple vacuum-assisted filtration method. Two different composite films were successfully fabricated and then tested: 1) a single-layer composite composed of a mixture of PEDOT:PSS and CNF phases and 2) a bilayer composite composed of an upper PEDOT:PSS membrane layer and a CNF matrix sub-layer. The latter composite was constructed by electrostatic/hydrogen bonding interactions between PEDOT:PSS and CNFs coupled with sequential vacuum-assisted filtration. Our results demonstrated that the resultant bilayer composite film exhibited a competitive electrical conductivity (ca. 22.6Scm -1 ) compared to those of previously reported cellulose-based composites. Furthermore, decreases in the electrical properties were not observed in the composite films when they were bent up to 100 times at an angle of 180° and bent multiple times at an angle of 90°, clearly demonstrating their excellent mechanical flexibility. This study provides a straightforward method of fabricating highly flexible, lightweight, and conductive films, which have the potential to be used in high-performance soft electronic systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Environmentally benign graphite intercalation compound composition for exfoliated graphite, flexible graphite, and nano-scaled graphene platelets

    Zhamu, Aruna; Jang, Bor Z.

    2014-06-17

    A carboxylic-intercalated graphite compound composition for the production of exfoliated graphite, flexible graphite, or nano-scaled graphene platelets. The composition comprises a layered graphite with interlayer spaces or interstices and a carboxylic acid residing in at least one of the interstices, wherein the composition is prepared by a chemical oxidation reaction which uses a combination of a carboxylic acid and hydrogen peroxide as an intercalate source. Alternatively, the composition may be prepared by an electrochemical reaction, which uses a carboxylic acid as both an electrolyte and an intercalate source. Exfoliation of the invented composition does not release undesirable chemical contaminants into air or drainage.

  5. Thermodynamics of aqueous electrolytes at various temperatures, pressures, and compositions. [Virial coefficients

    Pitzer, K.S.

    1979-09-01

    It is shown that the properties of fully ionized aqueous electrolyte systems can be represented by relatively simple equations over wide ranges of composition. There are only a few systems for which data are available over the full range to fused salt. A simple equation commonly used for nonelectrolytes fits the measured vapor pressure of water reasonably well and further refinements are clearly possible. Over the somewhat more limited composition range up to saturation of typical salts such as NaCl, the equations representing thermodynamic properties with a Debye-Hueckel term plus second and third virial coefficients are very successful and these coefficients are known for nearly 300 electrolytes at room temperature. These same equations effectively predict the properties of mixed electrolytes. A stringent test is offered by the calculation of all of the solubility relationships of the system Na-K-Mg-Ca-Cl-So{sub 4}-H{sub 2}0 and the calculated results of Harvie and Weare show excellent agreement with

  6. Lipid Oxidation Inhibitory Effects and Phenolic Composition of Aqueous Extracts from Medicinal Plants of Colombian Amazonia

    José Ignacio Ruiz-Sanz

    2012-05-01

    Full Text Available Diverse plants of ethnobotanic interest in Amazonia are commonly used in traditional medicine. We determined the antioxidant potential against lipid peroxidation, the antimicrobial activity, and the polyphenol composition of several Amazonian plants (Brownea rosademonte, Piper glandulosissimum, Piper krukoffii, Piper putumayoense, Solanum grandiflorum, and Vismia baccifera. Extracts from the plant leaf, bark, and stem were prepared as aqueous infusions, as used in folk medicine, and added to rat liver microsomes exposed to iron. The polyphenolic composition was detected by reverse-phase HPLC coupled to diode-array detector and MS/MS analysis. The antimicrobial activity was tested by the spot-on-a-lawn method against several indicator microorganisms. All the extracts inhibited lipid oxidation, except the P. glandulosissimum stem. The plant extracts exhibiting high antioxidant potential (V. baccifera and B. rosademonte contained high levels of flavanols (particularly, catechin and epicatechin. By contrast, S. grandiflorum leaf, which exhibited very low antioxidant activity, was rich in hydroxycinnamic acids. None of the extracts showed antimicrobial activity. This study demonstrates for the first time the presence of bioactive polyphenolic compounds in several Amazonian plants, and highlights the importance of flavanols as major phenolic contributors to antioxidant activity.

  7. Numerical Evaluation of Dynamic Response for Flexible Composite Structures under Slamming Impact for Naval Applications

    Hassoon, O. H.; Tarfaoui, M.; El Moumen, A.; Benyahia, H.; Nachtane, M.

    2018-06-01

    The deformable composite structures subjected to water-entry impact can be caused a phenomenon called hydroelastic effect, which can modified the fluid flow and estimated hydrodynamic loads comparing with rigid body. This is considered very important for ship design engineers to predict the global and the local hydrodynamic loads. This paper presents a numerical model to simulate the slamming water impact of flexible composite panels using an explicit finite element method. In order to better describe the hydroelastic influence and mechanical properties, composite materials panels with different stiffness and under different impact velocities with deadrise angle of 100 have been studied. In the other hand, the inertia effect was observed in the early stage of the impact that relative to the loading rate. Simulation results have been indicated that the lower stiffness panel has a higher hydroelastic effect and becomes more important when decreasing of the deadrise angle and increasing the impact velocity. Finally, the simulation results were compared with the experimental data and the analytical approaches of the rigid body to describe the behavior of the hydroelastic influence.

  8. Textile Dye Removal from Aqueous Solution using Modified Graphite Waste/Lanthanum/Chitosan Composite

    Kusrini, E.; Wicaksono, B.; Yulizar, Y.; Prasetyanto, EA; Gunawan, C.

    2018-03-01

    We investigated various pre-treatment processes of graphite waste using thermal, mechanical and chemical methods. The aim of this work is to study the performance of modified graphite waste/lanthanum/chitosan composite (MG) as adsorbent for textile dye removal from aqueous solution. Effect of graphite waste resources, adsorbent size and lanthanum concentration on the dye removal were studied in batch experiments. Selectivity of MG was also investigated. Pre-heated graphite waste (NMG) was conducted at 80°C for 1 h, followed by mechanical crushing of the resultant graphite to 75 μm particle size, giving adsorption performance of ˜58%, ˜67%, ˜93% and ˜98% of the model dye rhodamine B (concentration determined by UV-vis spectroscopy at 554 nm), methyl orange (464 nm), methylene blue (664 nm) and methyl violet (580 nm), respectively from aqueous solution. For this process, the system required less than ˜5 min for adsorbent material to be completely saturated with the adsorbate. Further chemical modification of the pre-treated graphite waste (MG) with lanthanum (0.01 – V 0.03 M) and chitosan (0.5% w/w) did not improve the performance of dye adsorption. Under comparable experimental conditions, as those of the ‘thermal-mechanical-pre-treated-only’ (NMG), modification of graphite waste (MG) with 0.03 M lanthanum and 0.5% w/w chitosan resulted in ˜14%, ˜47%, ˜72% and ˜85% adsorption of rhodamine B, methyl orange, methylene blue and methyl violet, respectively. Selective adsorption of methylene blue at most to ˜79%, followed by methyl orange, methyl violet and rhodamine B with adsorption efficiency ˜67, ˜38, and ˜9% sequentially using MG with 0.03 M lanthanum and 0.5% w/w chitosan.

  9. Thin-film composite materials as a dielectric layer for flexible metal-insulator-metal capacitors.

    Tiwari, Jitendra N; Meena, Jagan Singh; Wu, Chung-Shu; Tiwari, Rajanish N; Chu, Min-Ching; Chang, Feng-Chih; Ko, Fu-Hsiang

    2010-09-24

    A new organic-organic nanoscale composite thin-film (NCTF) dielectric has been synthesized by solution deposition of 1-bromoadamantane and triblock copolymer (Pluronic P123, BASF, EO20-PO70-EO20), in which the precursor solution has been achieved with organic additives. We have used a sol-gel process to make a metal-insulator-metal capacitor (MIM) comprising a nanoscale (10 nm-thick) thin-film on a flexible polyimide (PI) substrate at room temperature. Scanning electron microscope and atomic force microscope revealed that the deposited NCTFs were crack-free, uniform, highly resistant to moisture absorption, and well adhered on the Au-Cr/PI. The electrical properties of 1-bromoadamantane-P123 NCTF were characterized by dielectric constant, capacitance, and leakage current measurements. The 1-bromoadamantane-P123 NCTF on the PI substrate showed a low leakage current density of 5.5 x 10(-11) A cm(-2) and good capacitance of 2.4 fF at 1 MHz. In addition, the calculated dielectric constant of 1-bromoadamantane-P123 NCTF was 1.9, making them suitable candidates for use in future flexible electronic devices as a stable intermetal dielectric. The electrical insulating properties of 1-bromoadamantane-P123 NCTF have been improved due to the optimized dipole moments of the van der Waals interactions.

  10. Photovoltaic properties of conjugated polymer/fullerene composites on large area flexible substrates

    Desta Gebeyehu

    2000-06-01

    Full Text Available In this paper we present measurements of the photovoltaic response of bulk donor-acceptor heterojunction between the conjugated polymer, poly(3-octylthiophene, P3OT, (as a donor, D and fullerene (methanofullerene, (as acceptor, A, deposited between indium tin oxide and aluminum electrodes. The innovation involves the substrate, which is a polymer foil instead of glass. These devices are based on ultrafast, reversible, metastable photoinduced electron transfer and charge separation. We also present the efficiency and stability studies on large area (6 cm x 6 cm flexible plastic solar cells with monochromatic energy conversion efficiency (e of about 1.5% and carrier collection efficiency of nearly 20%. Further more, we have investigated the surface network morphology of these films layers by atomic force microscope (AFM. The development of solar cells based on composites of organic conjugated semi-conducting polymers with fullerene derivatives can provide a new method in the exploitation of solar energy.

  11. A biologically inspired artificial fish using flexible matrix composite actuators: analysis and experiment

    Zhang, Zhiye; Philen, Michael; Neu, Wayne

    2010-01-01

    A bio-inspired prototype fish using the flexible matrix composite (FMC) muscle technology for fin and body actuation is developed. FMC actuators are pressure driven muscle-like actuators capable of large displacements as well as large blocking forces. An analytical model of the artificial fish using FMC actuators is developed and analysis results are presented. An experimental prototype of the artificial fish having FMC artificial muscles has been completed and tested. Constant mean thrusts have been achieved in the laboratory for a stationary fish for different undulation frequencies around 1 Hz. The experimental results demonstrate that a nearly constant thrust can be achieved through tuning of excitation frequency for given body stiffness. Free swimming results show that the prototype can swim at approximately 0.3 m s −1

  12. Fully integrated carbon nanotube composite thin film strain sensors on flexible substrates for structural health monitoring

    Burton, A. R.; Lynch, J. P.; Kurata, M.; Law, K. H.

    2017-09-01

    Multifunctional thin film materials have opened many opportunities for novel sensing strategies for structural health monitoring. While past work has established methods of optimizing multifunctional materials to exhibit sensing properties, comparatively less work has focused on their integration into fully functional sensing systems capable of being deployed in the field. This study focuses on the advancement of a scalable fabrication process for the integration of multifunctional thin films into a fully integrated sensing system. This is achieved through the development of an optimized fabrication process that can create a broad range of sensing systems using multifunctional materials. A layer-by-layer deposited multifunctional composite consisting of single walled carbon nanotubes (SWNT) in a polyvinyl alcohol and polysodium-4-styrene sulfonate matrix are incorporated with a lithography process to produce a fully integrated sensing system deposited on a flexible substrate. To illustrate the process, a strain sensing platform consisting of a patterned SWNT-composite thin film as a strain-sensitive element within an amplified Wheatstone bridge sensing circuit is presented. Strain sensing is selected because it presents many of the design and processing challenges that are core to patterning multifunctional thin film materials into sensing systems. Strain sensors fabricated on a flexible polyimide substrate are experimentally tested under cyclic loading using standard four-point bending coupons and a partial-scale steel frame assembly under lateral loading. The study reveals the material process is highly repeatable to produce fully integrated strain sensors with linearity and sensitivity exceeding 0.99 and 5 {{V}}/{ε }, respectively. The thin film strain sensors are robust and are capable of high strain measurements beyond 3000 μ {ε }.

  13. Flexible Electrode Design: Fabrication of Freestanding Polyaniline-Based Composite Films for High-Performance Supercapacitors.

    Khosrozadeh, Ali; Darabi, Mohammad Ali; Xing, Malcolm; Wang, Quan

    2016-05-11

    Polyaniline (PANI) is a promising pseudocapacitance electrode material. However, its structural instability leads to low cyclic stability and limited rate capability which hinders its practical applications. In view of the limitations, flexible PANI-based composite films are developed to improve the electrochemical performance of electrode materials. We report in the research a facile and cost-effective approach for fabrication of a high-performance supercapacitor (SC) with excellent cyclic stability and tunable energy and power densities. SC electrode containing a very high mass loading of active materials is a flexible film of PANI, tissue wiper-based cellulose, graphite-based exfoliated graphite (ExG), and silver nanoparticles with potential applications in wearable electronics. The optimum preparation weight ratios of silver nitrate/aniline and ExG/aniline used in the research are estimated to be 0.18 and 0.65 (or higher), respectively. Our results show that an ultrahigh capacitance of 3.84 F/cm(2) (240.10 F/g) at a discharge rate of 5 mA can be achieved. In addition, our study shows that the power density can be increased from 1531.3 to 3000 W/kg by selecting the weight ratio of ExG/aniline to be more than 0.65, with a sacrifice in the energy density. The obtained promising electrochemical properties are found to be mainly attributed to an effective combination of PANI, ExG, cushiony cellulose scaffold, and silver as well as the porosity of the composite.

  14. Characterizations of nano-TiO{sub 2}/diatomite composites and their photocatalytic reduction of aqueous Cr (VI)

    Sun, Qing; Li, Hui; Zheng, Shuilin, E-mail: shuilinzh@sina.com; Sun, Zhiming, E-mail: szmcumtb@hotmail.com

    2014-08-30

    Graphical abstract: Nano-TiO{sub 2}/diatomite (DIA) composites were successfully synthesized by a typical hydrolysis precipitation method. The composites show good photocatalytic activity and stability for aqueous Cr (VI) removal. - Highlights: • TiO{sub 2} nanoparticles/diatomite composite was synthesized and characterized. • The composite exhibited a good photocatalytic performance in Cr (VI) reduction. • The photocatalyst showed good photocatalytic stability. • The composite is a promising material for Cr (VI) photocatalytic reduction. - Abstract: In this paper, the TiO{sub 2} nanoparticles were immobilized on diatomite (DIA) via a typical hydrolysis precipitation process using TiCl{sub 4} as precursor. The as-prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). TiO{sub 2} nanoparticles with the average grain size of around 7–14 nm were well deposited on the surface of diatomite. The photocatalytic activity toward the reduction of aqueous Cr (VI) was demonstrated under UV light. The influence of initial pH values, catalyst amount, illumination intensity and initial concentration of Cr (VI) on photocatalytic reduction of Cr (VI) were investigated. Compared with the commercial TiO{sub 2} (P25, Degussa), the TiO{sub 2}/DIA composites had better reactive activity because of their relatively higher adsorption capacity. Furthermore, the prepared photocatalyst exhibited relatively good photocatalytic stability depending on the reusability tests.

  15. PseKNC: a flexible web server for generating pseudo K-tuple nucleotide composition.

    Chen, Wei; Lei, Tian-Yu; Jin, Dian-Chuan; Lin, Hao; Chou, Kuo-Chen

    2014-07-01

    The pseudo oligonucleotide composition, or pseudo K-tuple nucleotide composition (PseKNC), can be used to represent a DNA or RNA sequence with a discrete model or vector yet still keep considerable sequence order information, particularly the global or long-range sequence order information, via the physicochemical properties of its constituent oligonucleotides. Therefore, the PseKNC approach may hold very high potential for enhancing the power in dealing with many problems in computational genomics and genome sequence analysis. However, dealing with different DNA or RNA problems may need different kinds of PseKNC. Here, we present a flexible and user-friendly web server for PseKNC (at http://lin.uestc.edu.cn/pseknc/default.aspx) by which users can easily generate many different modes of PseKNC according to their need by selecting various parameters and physicochemical properties. Furthermore, for the convenience of the vast majority of experimental scientists, a step-by-step guide is provided on how to use the current web server to generate their desired PseKNC without the need to follow the complicated mathematical equations, which are presented in this article just for the integrity of PseKNC formulation and its development. It is anticipated that the PseKNC web server will become a very useful tool in computational genomics and genome sequence analysis. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Flexible graphene composites for removal of methylene blue dye-contaminant from water

    Oliva, J.; Martinez, A. I.; Oliva, A. I.; Garcia, C. R.; Martinez-Luevanos, A.; Garcia-Lobato, M.; Ochoa-Valiente, R.; Berlanga, A.

    2018-04-01

    This work presents the use of flexible graphene composites (FGCs) fabricated by a casting method for the removal of Methylene blue (MB) dye from water. Those FGCs with elastic modulus of 15 MPa had enough mechanical resistance to support the Al2O3:Eu3+ and SrAl2O4:Bi3+ photocatalytic powders. After the incorporation of those powders in the FGCs, their photocatalytic activity was evaluated by monitoring the degradation of MB dye under solar irradiation. Scanning electron microscopy (SEM) images demonstrate that the surface of FGCs with catalysts powders presents pores with sizes in the range of 15-40 μm, which favored the sunlight absorption by scattering effects. Moreover, X-Ray diffraction measurements confirmed the formation of the composites by displacements of their diffraction peaks. The MB dye was completely removed (by photocatalysis and by physical adsorption) from the water after 180 min and 270 min by using the FGCs with Al2O3:Eu3+ and SrAl2O4:Bi3+ catalysts respectively. Hence, the results of photocatalytic activity suggest that our FGCs could be used as an effective support of catalyst powders for the easy removal of dye contaminants in wastewater treatment plants.

  17. Phytotoxic activity and chemical composition of aqueous volatile fractions from Eucalyptus species.

    Jinbiao Zhang

    Full Text Available The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.. The aqueous volatile fractions (AVFs were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph-mass spectrometry (GC-MS. Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species.

  18. Phytotoxic Activity and Chemical Composition of Aqueous Volatile Fractions from Eucalyptus Species

    Zhang, Jinbiao; An, Min; Wu, Hanwen; Liu, De Li; Stanton, Rex

    2014-01-01

    The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii) have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.). The aqueous volatile fractions (AVFs) were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions) during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph–mass spectrometry (GC-MS). Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species. PMID:24681490

  19. Removal of dieldrin from aqueous solution by a novel triolein-embedded composite adsorbent

    Ru Jia; Liu Huijuan; Qu Jiuhui; Wang Aimin; Dai Ruihua

    2007-01-01

    In this study, a novel triolein-embedded activated carbon composite adsorbent (CA-T) was prepared and applied for the adsorption and removal of dieldrin from aqueous systems. Experiments were carried out to investigate the adsorption behavior of dieldrin on CA-T, including adsorption isotherms, adsorption kinetics, the influence of initial concentration, temperature, shaking speed, pH and the addition of humic acid (HA) on adsorption. The adsorption isotherms accorded with Freundlich equation. Three kinetics models, including pseudo-first-order, pseudo-second-order and intraparticle diffusion models, were used to fit the experimental data. By comparing the correlation coefficients, it was found that both pseudo-second-order and intraparticle diffusion models were used to well describe the adsorption of dieldrin on CA-T. The addition of HA had little effect on dieldrin adsorption by CA-T. Results indicated that CA-T appeared to be a promising adsorbent for removing lipophilic dieldrin in trace amount, which was advantageous over pure granular activated carbon (GAC). The adsorption rate increased with increasing shaking speed, initial concentration and temperature, and remained almost unchanged in the pH range of 4-8. Thermodynamic calculations indicated that the adsorption reaction was spontaneous with a high affinity and the adsorption was an endothermic reaction

  20. Polyphenolic Composition and Antioxidant Activity of Aqueous and Ethanolic Extracts from Uncaria tomentosa Bark and Leaves.

    Navarro-Hoyos, Mirtha; Alvarado-Corella, Diego; Moreira-Gonzalez, Ileana; Arnaez-Serrano, Elizabeth; Monagas-Juan, Maria

    2018-05-11

    Uncaria tomentosa constitutes an important source of secondary metabolites with diverse biological activities mainly attributed until recently to alkaloids and triterpenes. We have previously reported for the first-time the polyphenolic profile of extracts from U. tomentosa , using a multi-step process involving organic solvents, as well as their antioxidant capacity, antimicrobial activity on aerial bacteria, and cytotoxicity on cancer cell lines. These promising results prompted the present study using food grade solvents suitable for the elaboration of commercial extracts. We report a detailed study on the polyphenolic composition of aqueous and ethanolic extracts of U. tomentosa bark and leaves ( n = 16), using High Performance Liquid Chromatography coupled with Mass Spectrometry (HPLC-DAD/TQ-ESI-MS). A total of 32 compounds were identified, including hydroxybenzoic and hydroxycinnamic acids, flavan-3-ols monomers, procyanidin dimers and trimers, flavalignans⁻cinchonains and propelargonidin dimers. Our findings showed that the leaves were the richest source of total phenolics and proanthocyanidins, in particular propelargonidin dimers. Two-way Analysis of Variance (ANOVA) indicated that the contents of procyanidin and propelargonidin dimers were significantly different ( p rich in proanthocyanidins and exhibiting high antioxidant activity.

  1. The Preparation of Carbon Nanotube/MnO2 Composite Fiber and Its Application to Flexible Micro-Supercapacitor

    Li Li

    2013-01-01

    Full Text Available In recent years, flexible electronic devices pursued for potential applications. The design and the fabrication of a novel flexible nanoarchitecture by coating electrical conductive MWCNT fiber with ultrathin films of MnO2 to achieve high specific capacitance, for micro-supercapacitors electrode applications, are demonstrated here. The MWCNT/MnO2 composite fiber electrode was prepared by the electrochemical deposition which was carried out through using two different methods: cyclic voltammetry and potentiostatic methods. The cyclic voltammetry method can get “crumpled paper ball” morphology MnO2 which has bigger specific capacitances than that achieved by potentiostatic method. The flexible micro-supercapacitor was fabricated by twisting two aligned MWCNT fibers and showed an area specific capacitance of 2.43 mF/cm2. The flexible micro-supercapacitors also enable promising applications in various fields.

  2. All-solid-state flexible supercapacitors based on highly dispersed polypyrrole nanowire and reduced graphene oxide composites.

    Yu, Chenfei; Ma, Peipei; Zhou, Xi; Wang, Anqi; Qian, Tao; Wu, Shishan; Chen, Qiang

    2014-10-22

    Highly dispersed polypyrrole nanowires are decorated on reduced graphene oxide sheets using a facile in situ synthesis route. The prepared composites exhibit high dispersibility, large effective surface area, and high electric conductivity. All-solid-state flexible supercapacitors are assembled based on the prepared composites, which show excellent electrochemical performances with a specific capacitance of 434.7 F g(-1) at a current density of 1 A g(-1). The as-fabricated supercapacitor also exhibits excellent cycling stability (88.1% capacitance retention after 5000 cycles) and exceptional mechanical flexibility. In addition, outstanding power and energy densities were obtained, demonstrating the significant potential of prepared material for flexible and portable energy storage devices.

  3. A paper-based electrode using a graphene dot/PEDOT:PSS composite for flexible solar cells

    Lee, Chuan-Pei; Lai, Kun-Yu; Lin, Chin-An; Li, Chun-Ting; Ho, Kuo-Chuan; Wu, Chih-I; Lau, Shu-Ping; He, Jr-Hau

    2017-01-01

    We have synthesized a metal-free composite ink that contains graphene dots (GDs) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) that can be used on paper to serve as the counter electrode in a flexible dye-sensitized solar

  4. Chapter 2.3 Cellulose Nanofibril Composite Substrates for Flexible Electronics

    Ronald Sabo; Jung-Hun Seo; Zhenqiang Ma

    2013-01-01

    Flexible electronics have a large number of potential applications, including malleable displays and wearable computers. Current research into high-speed, flexible electronic substrates uses plastics for the flexible substrate, but these plastics typically have drawbacks, such as high thermal expansion coefficients. Transparent films made from cellulose...

  5. Polyphenolic Composition and Antioxidant Activity of Aqueous and Ethanolic Extracts from Uncaria tomentosa Bark and Leaves

    Mirtha Navarro-Hoyos

    2018-05-01

    Full Text Available Uncaria tomentosa constitutes an important source of secondary metabolites with diverse biological activities mainly attributed until recently to alkaloids and triterpenes. We have previously reported for the first-time the polyphenolic profile of extracts from U. tomentosa, using a multi-step process involving organic solvents, as well as their antioxidant capacity, antimicrobial activity on aerial bacteria, and cytotoxicity on cancer cell lines. These promising results prompted the present study using food grade solvents suitable for the elaboration of commercial extracts. We report a detailed study on the polyphenolic composition of aqueous and ethanolic extracts of U. tomentosa bark and leaves (n = 16, using High Performance Liquid Chromatography coupled with Mass Spectrometry (HPLC-DAD/TQ-ESI-MS. A total of 32 compounds were identified, including hydroxybenzoic and hydroxycinnamic acids, flavan-3-ols monomers, procyanidin dimers and trimers, flavalignans–cinchonains and propelargonidin dimers. Our findings showed that the leaves were the richest source of total phenolics and proanthocyanidins, in particular propelargonidin dimers. Two-way Analysis of Variance (ANOVA indicated that the contents of procyanidin and propelargonidin dimers were significantly different (p < 0.05 in function of the plant part, and leaves extracts showed higher contents. Oxygen Radical Absorbance Capacity (ORAC and 2,2-diphenyl-1-picrylhidrazyl (DPPH values indicated higher antioxidant capacity for the leaves (p < 0.05. Further, correlation between both methods and procyanidin dimers was found, particularly between ORAC and propelargonidin dimers. Finally, Principal Component Analysis (PCA analysis results clearly indicated that the leaves are the richest plant part in proanthocyanidins and a very homogenous material, regardless of their origin. Therefore, our findings revealed that both ethanol and water extraction processes are adequate for the elaboration of

  6. Carbon nanotube/polymer composite electrodes for flexible, attachable electrochemical DNA sensors.

    Li, Jianfeng; Lee, Eun-Cheol

    2015-09-15

    All-solution-processed, easily-made, flexible multi-walled carbon nanotube (MWCNT)/polydimethylsiloxane (PDMS)-based electrodes were fabricated and used for electrochemical DNA sensors. These electrodes could serve as a recognition layer for DNA, without any surface modification, through π-π interactions between the MWCNTs and DNA, greatly simplifying the fabrication process for DNA sensors. The electrodes were directly connected to an electrochemical analyzer in the differential pulse voltammetry (DPV) and cyclic voltammetry (CV) measurements, where methylene blue was used as a redox indicator. Since neither functional groups nor probe DNA were immobilized on the surfaces of the electrodes, the sensor can be easily regenerated by washing these electrodes with water. The limit of detection was found to be 1.3 × 10(2)pM (S/N=3), with good DNA sequence differentiation ability. Fast fabrication of a DNA sensor was also achieved by cutting and attaching the MWCNT-PDMS composite electrodes at an analyte solution-containable region. Our results pave the way for developing user-fabricated easily attached DNA sensors at low costs. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Synthesis of reduced graphene oxide/ZnO nanorods composites on graphene coated PET flexible substrates

    Huang, Lei; Guo, Guilue; Liu, Yang; Chang, Quanhong; Shi, Wangzhou

    2013-01-01

    Graphical abstract: - Highlights: • ZnO nanorods synthesized on CVD-graphene and rGO surfaces, respectively. • ZnO/CVD-graphene and ZnO/rGO form a distinctive porous 3D structure. • rGO/ZnO nanostructures possibility in energy storage devices. - Abstract: In this work, reduced graphene oxide (rGO)/ZnO nanorods composites were synthesized on graphene coated PET flexible substrates. Both chemical vapor deposition (CVD) graphene and reduced graphene oxide (rGO) films were prepared following by hydrothermal growth of vertical aligned ZnO nanorods. Reduced graphene sheets were then spun coated on the ZnO materials to form a three dimensional (3D) porous nanostructure. The morphologies of the ZnO/CVD graphene and ZnO/rGO were investigated by SEM, which shows that the ZnO nanorods grown on rGO are larger in diameters and have lower density compared with those grown on CVD graphene substrate. As a result of fact, the rough surface of nano-scale ZnO on rGO film allows rGO droplets to seep into the large voids of ZnO nanorods, then to form the rGO/ZnO hierarchical structure. By comparison of the different results, we conclude that rGO/ZnO 3D nanostructure is more desirable for the application of energy storage devices

  8. Preparation of graphene/TiO2 composites by nonionic surfactant strategy and their simulated sunlight and visible light photocatalytic activity towards representative aqueous POPs degradation

    Li, Kexin; Xiong, Jingjing; Chen, Tong; Yan, Liushui; Dai, Yuhua; Song, Dongyang; Lv, Ying; Zeng, Zhenxing

    2013-01-01

    Highlights: ► A series of graphene/TiO 2 composites were developed by nonionic surfactant strategy. ► The textural property, optical property, and composition were well characterized. ► Aqueous POPs were degraded under simulated sunlight and visible light irradiation. ► The degradation mechanism and kinetics of aqueous POPs were studied in detail. ► Mineralization of aqueous POPs and recyclability of the composites were also tested. -- Abstract: A series of graphene/TiO 2 composites were fabricated using a single-step nonionic surfactant strategy combined with the solvothermal treatment technique. Their phase structure, morphology, porosity, optical absorption property, as well as composition and structure, were characterized. The as-prepared composites were successfully applied to degrade aqueous persistent organic pollutants (POPs) such as rhodamine B, aldicarb, and norfloxacin in simulated sunlight (λ > 320 nm) and visible light (λ > 400 nm) irradiation. The degradation mechanism and kinetics of aqueous POPs were studied in detail. The mineralization of aqueous POPs and the recyclability of the composites were also tested in the same condition

  9. Rapid removal of uranium from aqueous solutions using magnetic Fe3O4@SiO2 composite particles.

    Fan, Fang-Li; Qin, Zhi; Bai, Jing; Rong, Wei-Dong; Fan, Fu-You; Tian, Wei; Wu, Xiao-Lei; Wang, Yang; Zhao, Liang

    2012-04-01

    Rapid removal of U(VI) from aqueous solutions was investigated using magnetic Fe(3)O(4)@SiO(2) composite particles as the novel adsorbent. Batch experiments were conducted to study the effects of initial pH, amount of adsorbent, shaking time and initial U(VI) concentrations on uranium sorption efficiency as well as the desorbing of U(VI). The sorption of uranium on Fe(3)O(4)@SiO(2) composite particles was pH-dependent, and the optimal pH was 6.0. In kinetics studies, the sorption equilibrium can be reached within 180 min, and the experimental data were well fitted by the pseudo-second-order model, and the equilibrium sorption capacities calculated by the model were almost the same as those determined by experiments. The Langmuir sorption isotherm model correlates well with the uranium sorption equilibrium data for the concentration range of 20-200 mg/L. The maximum uranium sorption capacity onto magnetic Fe(3)O(4)@SiO(2) composite particles was estimated to be about 52 mg/g at 25 °C. The highest values of uranium desorption (98%) was achieved using 0.01 M HCl as the desorbing agent. Fe(3)O(4)@SiO(2) composite particles showed a good selectivity for uranium from aqueous solution with other interfering cation ions. Present study suggested that magnetic Fe(3)O(4)@SiO(2) composite particles can be used as a potential adsorbent for sorption uranium and also provided a simple, fast separation method for removal of heavy metal ion from aqueous solution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. A paper-based electrode using a graphene dot/PEDOT:PSS composite for flexible solar cells

    Lee, Chuan-Pei

    2017-04-22

    We have synthesized a metal-free composite ink that contains graphene dots (GDs) and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) that can be used on paper to serve as the counter electrode in a flexible dye-sensitized solar cell (DSSC). This paper-based GD/PEDOT:PSS electrode is low-cost, light-weight, flexible, environmentally friendly, and easy to cut and process for device fabrication. We determined the GD/PEDOT:PSS composite effectively fills the dense micro-pores in the paper substrate, which leads to improved carrier transport in the electrode and a 3-fold enhanced cell efficiency as compared to the paper electrode made with sputtered Pt. Moreover, the DSSC with the paper electrode featuring the GD/PEDOT:PSS composite did not fail in photovoltaic tests even after bending the electrode 150 times, whereas the device made with the Pt-based paper electrode decreased in efficiency by 45% after such manipulation. These exceptional properties make the metal-free GD/PEDOT:PSS composite ink a promising electrode material for a wide variety of flexible electronic applications.

  11. Quantitative analysis of aqueous phase composition of model dentin adhesives experiencing phase separation

    Ye, Qiang; Park, Jonggu; Parthasarathy, Ranganathan; Pamatmat, Francis; Misra, Anil; Laurence, Jennifer S.; Marangos, Orestes; Spencer, Paulette

    2013-01-01

    There have been reports of the sensitivity of our current dentin adhesives to excess moisture, for example, water-blisters in adhesives placed on over-wet surfaces, and phase separation with concomitant limited infiltration of the critical dimethacrylate component into the demineralized dentin matrix. To determine quantitatively the hydrophobic/hydrophilic components in the aqueous phase when exposed to over-wet environments, model adhesives were mixed with 16, 33, and 50 wt % water to yield well-separated phases. Based upon high-performance liquid chromatography coupled with photodiode array detection, it was found that the amounts of hydrophobic BisGMA and hydrophobic initiators are less than 0.1 wt % in the aqueous phase. The amount of these compounds decreased with an increase in the initial water content. The major components of the aqueous phase were hydroxyethyl methacrylate (HEMA) and water, and the HEMA content ranged from 18.3 to 14.7 wt %. Different BisGMA homologues and the relative content of these homologues in the aqueous phase have been identified; however, the amount of crosslinkable BisGMA was minimal and, thus, could not help in the formation of a crosslinked polymer network in the aqueous phase. Without the protection afforded by a strong crosslinked network, the poorly photoreactive compounds of this aqueous phase could be leached easily. These results suggest that adhesive formulations should be designed to include hydrophilic multimethacrylate monomers and water compatible initiators. PMID:22331596

  12. Flexible microstrip antenna based on carbon nanotubes/(ethylene-octene copolymer) thin composite layer deposited on PET substrate

    Matyas, J.; Olejnik, R.; Slobodian, P.

    2017-12-01

    A most of portable devices, such as mobile phones, tablets, uses antennas made of cupper. In this paper we demonstrate possible use of electrically conductive polymer composite material for such antenna application. Here we describe the method of preparation and properties of the carbon nanotubes (CNTs)/(ethylene-octene copolymer) as flexible microstrip antenna. Carbon nanotubes dispersion in (ethylene-octene copolymer) toluene solution was prepared by ultrasound finally coating PET substrate by method of dip-coating. Main advantages of PET substrate are low weight and also flexibility. The final size of flexible microstrip antenna was 5 x 50 mm with thickness of 0.48 mm (PET substrate 0.25 mm) with the weight of only 0.402 g. Antenna operates at three frequencies 1.66 GHz (-6.51 dB), 2.3 GHz (-13 dB) and 2.98 GHz (-33.59 dB).

  13. Polyimide-Epoxy Composites with Superior Bendable Properties for Application in Flexible Electronics

    Lee, Sangyoup; Yoo, Taewon; Han, Youngyu; Kim, Hanglim; Han, Haksoo

    2017-08-01

    The need for flexible electronics with outstanding bending properties is increasing due to the demand for wearable devices and next-generation flexible or rollable smartphones. In addition, the requirements for flexible or rigid-flexible electronics are sharply increasing to achieve the design of space-saving electronic devices. In this regard, coverlay (CL) film is a key material used in the bending area of flexible electronics, albeit infrequently. Because flexible electronics undergo folding and unfolding numerous times, CL films with superior mechanical and bending properties are required so that the bending area can endure such severe stress. However, because current CL films are only used for a designated bending area in the flexible electronics panel, their highly complicated and expensive manufacturing procedure is a disadvantage. In addition, the thickness of CL films must be decreased to satisfy the ongoing requirement for increasingly thin products. However, due to the limitations of the two-layer structure of existing CL films, the manufacturing process cannot be made more cost effective by simply applying more thin film onto the board. To address this problem, we have developed liquid coverlay inks (LCIs) with superior bendable properties, in comparison with CL films, when applied onto flexible electronics using a screen-printing method. The results show that LCIs have the potential to become one of the leading candidates to replace existing CL films because of their lower cost and faster manufacturing process.

  14. Fog composition at Baengnyeong Island in the eastern Yellow Sea: detecting markers of aqueous atmospheric oxidations

    A. J. Boris

    2016-01-01

    Full Text Available Samples of fog water were collected at Baengnyeong Island (BYI in the Yellow Sea during the summer of 2014. The most abundant chemical species in the fog water were NH4+ (mean of 2220 µM, NO3− (1260 µM, SO4−2 (730 µM, and Na+ (551 µM, with substantial contributions from other species consistent with marine and biomass burning influence on some dates. The pH of the samples ranged between 3.48 and 5.00, with a mean of 3.94, intermediate within pH values of fog/cloud water reported previously in Southeast Asia. Back trajectories (72 h showed that high relative humidity ( >  80 % was encountered upwind of the sampling site by all but one of the sampled air masses, and that the fog composition at BYI can be impacted by several different source regions, including the Sea of Japan, southeastern China, northeastern China, and the East China Sea. Sulfur in the collected fog was highly oxidized: low S(IV concentrations were measured (mean of 2.36 µM in contrast to SO4−2 and in contrast to fog/cloud S(IV concentrations from pollutant source regions; organosulfate species were also observed and were most likely formed through aging of mainly biogenic volatile organic compounds. Low-molecular-mass organic acids were major contributors to total organic carbon (TOC; 36–69 %, comprising a fraction of TOC at the upper end of that seen in fogs and clouds in other polluted environments. Large contributions were observed from not only acetic and formic acids but also oxalic, succinic, maleic, and other organic acids that can be produced in aqueous atmospheric organic processing (AAOP reactions. These samples of East Asian fog water containing highly oxidized components represent fog downwind of pollutant sources and can provide new insight into the fate of regional emissions. In particular, these samples demonstrate the result of extensive photochemical aging during multiday transport, including oxidation within wet aerosols and

  15. Fog composition at Baengnyeong Island in the eastern Yellow Sea: detecting markers of aqueous atmospheric oxidations

    Boris, A. J.; Lee, T.; Park, T.; Choi, J.; Seo, S. J.; Collett, J. L., Jr.

    2016-01-01

    Samples of fog water were collected at Baengnyeong Island (BYI) in the Yellow Sea during the summer of 2014. The most abundant chemical species in the fog water were NH4+ (mean of 2220 µM), NO3- (1260 µM), SO4-2 (730 µM), and Na+ (551 µM), with substantial contributions from other species consistent with marine and biomass burning influence on some dates. The pH of the samples ranged between 3.48 and 5.00, with a mean of 3.94, intermediate within pH values of fog/cloud water reported previously in Southeast Asia. Back trajectories (72 h) showed that high relative humidity ( > 80 %) was encountered upwind of the sampling site by all but one of the sampled air masses, and that the fog composition at BYI can be impacted by several different source regions, including the Sea of Japan, southeastern China, northeastern China, and the East China Sea. Sulfur in the collected fog was highly oxidized: low S(IV) concentrations were measured (mean of 2.36 µM) in contrast to SO4-2 and in contrast to fog/cloud S(IV) concentrations from pollutant source regions; organosulfate species were also observed and were most likely formed through aging of mainly biogenic volatile organic compounds. Low-molecular-mass organic acids were major contributors to total organic carbon (TOC; 36-69 %), comprising a fraction of TOC at the upper end of that seen in fogs and clouds in other polluted environments. Large contributions were observed from not only acetic and formic acids but also oxalic, succinic, maleic, and other organic acids that can be produced in aqueous atmospheric organic processing (AAOP) reactions. These samples of East Asian fog water containing highly oxidized components represent fog downwind of pollutant sources and can provide new insight into the fate of regional emissions. In particular, these samples demonstrate the result of extensive photochemical aging during multiday transport, including oxidation within wet aerosols and fogs.

  16. High-performance flexible resistive memory devices based on Al2O3:GeOx composite

    Behera, Bhagaban; Maity, Sarmistha; Katiyar, Ajit K.; Das, Samaresh

    2018-05-01

    In this study a resistive switching random access memory device using Al2O3:GeOx composite thin films on flexible substrate is presented. A bipolar switching characteristic was observed for the co-sputter deposited Al2O3:GeOx composite thin films. Al/Al2O3:GeOx/ITO/PET memory device shows excellent ON/OFF ratio (∼104) and endurance (>500 cycles). GeOx nanocrystals embedded in the Al2O3 matrix have been found to play a significant role in enhancing the switching characteristics by facilitating oxygen vacancy formation. Mechanical endurance was retained even after several bending. The conduction mechanism of the device was qualitatively discussed by considering Ohmic and SCLC conduction. This flexible device is a potential candidate for next-generation electronics device.

  17. Induced liquid-crystalline ordering in solutions of stiff and flexible amphiphilic macromolecules: Effect of mixture composition

    Glagolev, Mikhail K.; Vasilevskaya, Valentina V.; Khokhlov, Alexei R.

    2016-01-01

    Impact of mixture composition on self-organization in concentrated solutions of stiff helical and flexible macromolecules was studied by means of molecular dynamics simulation. The macromolecules were composed of identical amphiphilic monomer units but a fraction f of macromolecules had stiff helical backbones and the remaining chains were flexible. In poor solvents the compacted flexible macromolecules coexist with bundles or filament clusters from few intertwined stiff helical macromolecules. The increase of relative content f of helical macromolecules leads to increase of the length of helical clusters, to alignment of clusters with each other, and then to liquid-crystalline-like ordering along a single direction. The formation of filament clusters causes segregation of helical and flexible macromolecules and the alignment of the filaments induces effective liquid-like ordering of flexible macromolecules. A visual analysis and calculation of order parameter relaying the anisotropy of diffraction allow concluding that transition from disordered to liquid-crystalline state proceeds sharply at relatively low content of stiff components.

  18. Flexible n-type thermoelectric composite films with enhanced performance through interface engineering and post-treatment

    An, Hyeunhwan; Karas, Dale; Kim, Byung-Wook; Trabia, Sarah; Moon, Jaeyun

    2018-07-01

    Flexible thermoelectric (TE) materials, which are devices that convert thermal gradients to electrical energy, have attracted interest for practical energy-harvesting/recovery applications. However, as compared with p-type materials, the progress on the development of n-type TE flexible materials has been slow due to difficulties involved in n-type doping techniques. This study used high mobility carbon nanotubes (CNTs) to a uniformly mixed hybrid-composite, resulting in an enhanced power factor by increasing electrical conductivity. The energy filtering effect and stoichiometric composition of the material used, bismuth telluride (Bi2Te3) correlated to a significant enhancement in TE performance, with a power factor of 225.9 μW m‑1K‑2 at room temperature: a factor of 65 higher than as-fabricated composite film. This paper describes a simplified synthesis for the preparation of the composite film that eliminates time-intensive and cost-prohibitive processing, traditionally seen during extrusion and dicing inorganic manufacturing. The resulting post-annealed composite film consisting of Bi2Te3 nanowire and CNTs demonstrate a promising candidate for material that can be used for an n-type TE device that has improved energy conversion efficiency.

  19. Thin and Flexible Fe-Si-B/Ni-Cu-P Metallic Glass Multilayer Composites for Efficient Electromagnetic Interference Shielding.

    Zhang, Jijun; Li, Jiawei; Tan, Guoguo; Hu, Renchao; Wang, Junqiang; Chang, Chuntao; Wang, Xinmin

    2017-12-06

    Thin and flexible materials that can provide efficient electromagnetic interference (EMI) shielding are urgently needed, especially if they can be easily processed and withstand harsh environments. Herein, layer-structured Fe-Si-B/Ni-Cu-P metallic glass composites have been developed by simple electroless plating Ni-Cu-P coating on commercial Fe-Si-B metallic glasses. The 0.1 mm-thick composite shows EMI shielding effectiveness of 40 dB over the X-band frequency range, which is higher than those of traditional metals, metal oxides, and their polymer composites of larger thickness. Most of the applied electromagnetic waves are proved to be absorbed rather than bounced back. This performance originates from the combination of a superior soft magnetic property, excellent electrical conductivity, and multiple internal reflections from multilayer composites. In addition, the flexible composites also exhibit good corrosion resistance, high thermal stability, and excellent tensile strength, making them suitable for EMI shielding in harsh chemical or thermal environments.

  20. Adsorption of Pb(II) from aqueous solution using a magnetic chitosan/graphene oxide composite and its toxicity studies.

    Melvin Samuel, S; Shah, Sk Sheriff; Bhattacharya, Jayanta; Subramaniam, Kalidass; Pradeep Singh, N D

    2018-05-02

    This study involves the adsorption of lead using magnetic chitosan/graphene oxide (MCGO) composite material in batch mode. The MCGO composite material was synthesized via modified Hummers method. The MCGO composite material was characterized by powder x-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Tunnelling electron microscopy (TEM), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) and UV-vis diffusive reflectance spectra. The adsorption mechanism of MCGO composite material was well described by Langmuir isotherm and pseudo second order kinetic model, with a high regression coefficient (composite material was applied for the removal of lead metal from aqueous solution. We have also evaluated toxicity of synthesized MCGO composite material by examining on A549 cells. The results have shown that MCGO material showed viable cell percentage of 53.7% at 50 μg and 44.8% at 100 μg. Copyright © 2017. Published by Elsevier B.V.

  1. Study of trunk flexibility and body composition between football and badminton players

    NANDALAL SINGH

    2011-04-01

    Full Text Available The purpose of the present study was an attempt to compare the flexibility (trunk flexibility and bodycomposition (percentage of body fat, total body fat and lean body mass between inter-college level malefootball and badminton players. Fifty (50 male inter-college level football players (N=25 and badmintonplayers (N=25 ranging between 17 to 25years were selected randomly from different colleges of PanjabUniversity, Chandigarh for this study. To compare the mean differences between the inter-college level footballand badminton players,t tests were computed using SPSS Software. Flexibility (trunk flexibility, and bodycomposition (percentage of body fat and total body fat were not found to be statistically significant

  2. Innovative micro-textured hydroxyapatite and poly(l-lactic)-acid polymer composite film as a flexible, corrosion resistant, biocompatible, and bioactive coating for Mg implants.

    Kim, Sae-Mi; Kang, Min-Ho; Kim, Hyoun-Ee; Lim, Ho-Kyung; Byun, Soo-Hwan; Lee, Jong-Ho; Lee, Sung-Mi

    2017-12-01

    The utility of a novel ceramic/polymer-composite coating with a micro-textured microstructure that would significantly enhance the functions of biodegradable Mg implants is demonstrated here. To accomplish this, bioactive hydroxyapatite (HA) micro-dots can be created by immersing a Mg implant with a micro-patterned photoresist surface in an aqueous solution containing calcium and phosphate ions. The HA micro-dots can then be surrounded by a flexible poly(l-lactic)-acid (PLLA) polymer using spin coating to form a HA/PLLA micro-textured coating layer. The HA/PLLA micro-textured coating layer showed an excellent corrosion resistance when it was immersed in a simulated body fluid (SBF) solution and good biocompatibility, which was assessed by in vitro cell tests. In addition, the HA/PLLA micro-textured coating layer had high deformation ability, where no apparent changes in the coating layer were observed even after a 5% elongation, which would be unobtainable using HA and PLLA coating layers; furthermore, this allowed the mechanically-strained Mg implant with the HA/PLLA micro-textured coating layer to preserve its excellent corrosion resistance and biocompatibility in vitro. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Polymorphous Supercapacitors Constructed from Flexible Three-Dimensional Carbon Network/Polyaniline/MnO2 Composite Textiles.

    Wang, Jinjie; Dong, Liubing; Xu, Chengjun; Ren, Danyang; Ma, Xinpei; Kang, Feiyu

    2018-04-04

    Polymorphous supercapacitors were constructed from flexible three-dimensional carbon network/polyaniline (PANI)/MnO 2 composite textile electrodes. The flexible textile electrodes were fabricated through a layer-by-layer construction strategy: PANI, carbon nanotubes (CNTs), and MnO 2 were deposited on activated carbon fiber cloth (ACFC) in turn through an electropolymerization process, "dipping and drying" method, and in situ chemical reaction, respectively. In the fabricated ACFC/PANI/CNTs/MnO 2 textile electrodes, the ACFC/CNT hybrid framework serves as a porous and electrically conductive 3D network for the rapid transmission of electrons and electrolyte ions, where ACFC, PANI, and MnO 2 are high-performance supercapacitor electrode materials. In the electrolyte of H 2 SO 4 solution, the textile electrode-based symmetric supercapacitor delivers superior areal capacitance, energy density, and power density of 4615 mF cm -2 (for single electrode), 157 μW h cm -2 , and 10372 μW cm -2 , respectively, whereas asymmetric supercapacitor assembled with the prepared composite textile as the positive electrode and ACFC as the negative electrode exhibits an improved energy density of 413 μW h cm -2 and a power density of 16120 μW cm -2 . On the basis of the ACFC/PANI/CNTs/MnO 2 textile electrodes, symmetric and asymmetric solid-state textile supercapacitors with a PVA/H 2 SO 4 gel electrolyte were also produced. These solid-state textile supercapacitors exhibit good electrochemical performance and high flexibility. Furthermore, flexible solid-state fiber-like supercapacitors were prepared with fiber bundle electrodes dismantled from the above composite textiles. Overall, this work makes a meaningful exploration of the versatile applications of textile electrodes to produce polymorphous supercapacitors.

  4. Effects of Operating Temperature on Droplet Casting of Flexible Polymer/Multi-Walled Carbon Nanotube Composite Gas Sensors

    Jin-Chern Chiou

    2016-12-01

    Full Text Available This study examined the performance of a flexible polymer/multi-walled carbon nanotube (MWCNT composite sensor array as a function of operating temperature. The response magnitudes of a cost-effective flexible gas sensor array equipped with a heater were measured with respect to five different operating temperatures (room temperature, 40 °C, 50 °C, 60 °C, and 70 °C via impedance spectrum measurement and sensing response experiments. The selected polymers that were droplet cast to coat a MWCNT conductive layer to form two-layer polymer/MWCNT composite sensing films included ethyl cellulose (EC, polyethylene oxide (PEO, and polyvinylpyrrolidone (PVP. Electrical characterization of impedance, sensing response magnitude, and scanning electron microscope (SEM morphology of each type of polymer/MWCNT composite film was performed at different operating temperatures. With respect to ethanol, the response magnitude of the sensor decreased with increasing operating temperatures. The results indicated that the higher operating temperature could reduce the response and influence the sensitivity of the polymer/MWCNT gas sensor array. The morphology of polymer/MWCNT composite films revealed that there were changes in the porous film after volatile organic compound (VOC testing.

  5. Flexible and conductive waste tire-derived carbon/polymer composite paper as pseudocapacitive electrode

    Naskar, Amit K.; Paranthaman, Mariappan Parans; Boota, Muhammad; Gogotsi, Yury

    2018-04-10

    A method of making a supercapacitor from waste tires, includes the steps of providing rubber pieces and contacting the rubber pieces with a sulfonation bath to produce sulfonated rubber; pyrolyzing the sulfonated rubber to produce a tire-derived carbon composite comprising carbon black embedded in rubber-derived carbon matrix comprising graphitized interface portions; activating the tire-derived carbon composite by contacting the tire-derived carbon composite with a specific surface area-increasing composition to increase the specific surface area of the carbon composite to provide an activated tire-derived carbon composite; and, mixing the activated tire-derived carbon composite with a monomer and polymerizing the monomer to produce a redox-active polymer coated, activated tire-derived carbon composite. The redox-active polymer coated, activated tire-derived carbon composite can be formed into a film. An electrode and a supercapacitor are also disclosed.

  6. High performance supercapacitors based on three-dimensional ultralight flexible manganese oxide nanosheets/carbon foam composites

    He, Shuijian; Chen, Wei

    2014-09-01

    The syntheses and capacitance performances of ultralight and flexible MnO2/carbon foam (MnO2/CF) hybrids are systematically studied. Flexible carbon foam with a low mass density of 6.2 mg cm-3 and high porosity of 99.66% is simply obtained by carbonization of commercially available and low-cost melamine resin foam. With the high porous carbon foam as framework, ultrathin MnO2 nanosheets are grown through in situ redox reaction between KMnO4 and carbon foam. The three-dimensional (3D) MnO2/CF networks exhibit highly ordered hierarchical pore structure. Attributed to the good flexibility and ultralight weight, the MnO2/CF nanomaterials can be directly fabricated into supercapacitor electrodes without any binder and conductive agents. Moreover, the pseudocapacitance of the MnO2 nanosheets is enhanced by the fast ion diffusion in the three-dimensional porous architecture and by the conductive carbon foam skeleton as well as good contact of carbon/oxide interfaces. Supercapacitor based on the MnO2/CF composite with 3.4% weight percent of MnO2 shows a high specific capacitance of 1270.5 F g-1 (92.7% of the theoretical specific capacitance of MnO2) and high energy density of 86.2 Wh kg-1. The excellent capacitance performance of the present 3D ultralight and flexible nanomaterials make them promising candidates as electrode materials for supercapacitors.

  7. Freestanding three-dimensional graphene/MnO2 composite networks as ultralight and flexible supercapacitor electrodes.

    He, Yongmin; Chen, Wanjun; Li, Xiaodong; Zhang, Zhenxing; Fu, Jiecai; Zhao, Changhui; Xie, Erqing

    2013-01-22

    A lightweight, flexible, and highly efficient energy management strategy is needed for flexible energy-storage devices to meet a rapidly growing demand. Graphene-based flexible supercapacitors are one of the most promising candidates because of their intriguing features. In this report, we describe the use of freestanding, lightweight (0.75 mg/cm(2)), ultrathin (rate of 2 mV/s. With a view to practical applications, we have further optimized the MnO(2) content with respect to the entire electrode and achieved a maximum specific capacitance of 130 F/g. In addition, we have also explored the excellent electrochemical performance of a symmetrical supercapacitor (of weight less than 10 mg and thickness ~0.8 mm) consisting of a sandwich structure of two pieces of 3D graphene/MnO(2) composite network separated by a membrane and encapsulated in polyethylene terephthalate (PET) membranes. This research might provide a method for flexible, lightweight, high-performance, low-cost, and environmentally friendly materials used in energy conversion and storage systems for the effective use of renewable energy.

  8. Removal of Cr(VI and Toxic Ions from Aqueous Solutions and Tannery Wastewater Using Polymer-Clay Composites

    Abd El-Azeem Sallam

    2017-10-01

    Full Text Available Polymer-clay composites were prepared by natural zeolite (clinoptilolite or naturally local clay deposits in an N,N-methylene-bis-acrylamide as cross-linked. The resultant composites were used for the removal of Cr(VI from an aqueous solution. Additionally, their effects on soluble ions of tannery wastewater were investigated. The produced composites were characterized using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, and scanning electron microscopy (SEM. The results showed that Cr(VI removal is dependent upon initial concentrations and pH. The adsorption quantity of Cr(VI onto the polymerized clay deposit followed by polymerized zeolite exhibited higher values than their original samples. The polymer-clay composite of clay deposit showed the highest removal of 76.3–100% overall initial concentrations of 10–50 mg L−1 and at initial pH of 2. Kinetics of Cr(VI removal by various sorbents was predicted using a pseudo–second order model. Our findings showed that the levels of salinity and various soluble ions (Cr2+, Na+, Cl− and SO42− in tannery wastewater are very high, and their levels were reduced after treatment, especially by polymerized sorbents. It could be concluded that the polymer-clay composites may be employed as a highly efficient sorbent for the removal of Cr(VI and toxic ions from the wastewater.

  9. Characterizations of nano-TiO2/diatomite composites and their photocatalytic reduction of aqueous Cr (VI)

    Sun, Qing; Li, Hui; Zheng, Shuilin; Sun, Zhiming

    2014-08-01

    In this paper, the TiO2 nanoparticles were immobilized on diatomite (DIA) via a typical hydrolysis precipitation process using TiCl4 as precursor. The as-prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). TiO2 nanoparticles with the average grain size of around 7-14 nm were well deposited on the surface of diatomite. The photocatalytic activity toward the reduction of aqueous Cr (VI) was demonstrated under UV light. The influence of initial pH values, catalyst amount, illumination intensity and initial concentration of Cr (VI) on photocatalytic reduction of Cr (VI) were investigated. Compared with the commercial TiO2 (P25, Degussa), the TiO2/DIA composites had better reactive activity because of their relatively higher adsorption capacity. Furthermore, the prepared photocatalyst exhibited relatively good photocatalytic stability depending on the reusability tests.

  10. Compositional evolution of particle-phase reaction products and water in the heterogeneous OH oxidation of model aqueous organic aerosols

    M. M. Chim

    2017-12-01

    Full Text Available Organic compounds present at or near the surface of aqueous droplets can be efficiently oxidized by gas-phase OH radicals, which alter the molecular distribution of the reaction products within the droplet. A change in aerosol composition affects the hygroscopicity and leads to a concomitant response in the equilibrium amount of particle-phase water. The variation in the aerosol water content affects the aerosol size and physicochemical properties, which in turn governs the oxidation kinetics and chemistry. To attain better knowledge of the compositional evolution of aqueous organic droplets during oxidation, this work investigates the heterogeneous OH-radical-initiated oxidation of aqueous methylsuccinic acid (C5H8O4 droplets, a model compound for small branched dicarboxylic acids found in atmospheric aerosols, at a high relative humidity of 85 % through experimental and modeling approaches. Aerosol mass spectra measured by a soft atmospheric pressure ionization source (Direct Analysis in Real Time, DART coupled with a high-resolution mass spectrometer reveal two major products: a five carbon atom (C5 hydroxyl functionalization product (C5H8O5 and a C4 fragmentation product (C4H6O3. These two products likely originate from the formation and subsequent reactions (intermolecular hydrogen abstraction and carbon–carbon bond scission of tertiary alkoxy radicals resulting from the OH abstraction occurring at the methyl-substituted carbon site. Based on the identification of the reaction products, a kinetic model of oxidation (a two-product model coupled with the Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients (AIOMFAC model is built to simulate the size and compositional changes of aqueous methylsuccinic acid droplets during oxidation. Model results show that at the maximum OH exposure, the droplets become slightly more hygroscopic after oxidation, as the mass fraction of water is predicted to increase from

  11. Highly Conductive, Transparent Flexible Films Based on Metal Nanoparticle-Carbon Nanotube Composites

    Wen-Yin Ko

    2013-01-01

    Full Text Available Metallic nanoparticles decorated on MWCNTs based transparent conducting thin films (TCFs show a cheap and efficient option for the applications in touch screens and the replacement of the ITO film because of their interesting properties of electrical conductivity, mechanical property, chemical inertness, and other unique properties, which may not be accessible by their individual components. However, a great challenge that always remains is to develop effective ways to prepare junctions between metallic nanoparticles and MWCNTs for the improvement of high-energy barriers, high contact resistances, and weak interactions which could lead to the formation of poor conducting pathways and result in the CNT-based devices with low mechanical flexibility. Herein, we not only discuss recent progress in the preparation of MNP-CNT flexible TCFs but also describe our research studies in the relevant areas. Our result demonstrated that the MNP-CNT flexible TCFs we prepared could achieve a highly electrical conductivity with the sheet resistance of ~100 ohm/sq with ~80% transmittance at 550 nm even after being bent 500 times. This electrical conductivity is much superior to the performances of other MWCNT-based transparent flexible films, making it favorable for next-generation flexible touch screens and optoelectronic devices.

  12. Influence of age, sexual maturation, anthropometric variables and body composition on flexibility

    Keila Donassolo Santos

    2010-04-01

    Full Text Available Since flexibility is an important component of health-related physical fitness at all ages, this parameter should be evaluated in chi ldren and adolescent s because the abi l ity to acquire and maintain levels of flexibility is greater in this age group. Thus, the objective of this study was to evaluate body weight, height, BMI and flexibility according to chronological age and sexual maturat ion and to determine the influence of these var iables on flexibi l ity in student s f rom publ ic and private schools. A cross-sectional descriptive and analytical study was conducted. The sample consisted of 2604 girls aged 8 to 17 years. Body weight, height, BMI, sexual maturation, and flexibility were evaluated. The data were analyzed descriptively using the following inferential tests: two-way analysis of variance (ANOVA followed by the Tukey post-hoc test, Pearson’s and Spearman’s simple correlation coefficients, and stepwise multiple regression analysis. The SPSS® 13.0 program was used for all statistical analyses, with a level of significance of p<0.05. Significant differences with increasing age and maturation stage were observed for the variables body weight, height and BMI when compared to the subsequent year. In conclusion, body wei-ght and height increased with increasing age, especially between 8 and 13 years, and flexibility remained stable throughout childhood and adolescence.

  13. Functional polyaniline/multiwalled carbon nanotube composite as an efficient adsorbent material for removing pharmaceuticals from aqueous media.

    Dutra, Flávia Viana Avelar; Pires, Bruna Carneiro; Nascimento, Tienne Aparecida; Borges, Keyller Bastos

    2018-09-01

    The composite polyaniline/multiwalled carbon nanotube (PAni/MWCNT, 1:0.1 w/w) was developed with the intention of binding the adsorbent properties of two materials and using it to adsorb pharmaceuticals from aqueous media. PAni/MWCNT was characterized by scanning electron microscopy, thermogravimetry, infrared spectroscopy, pH at the point of zero charge, and the effect on the surface wettability of the material. As proof of concept, adsorption studies were carried out using meloxicam (MLX) as the pharmaceutical and it was evaluated as a function of pH, temperature, ionic strength, contact time and variation in concentration. Kinetics and isothermal models were applied to evaluate the mechanism of the adsorption process. The best MLX adsorption result was at pH 2 with 6 min of contact with PAni/MWCNT. The kinetics models that fitted the experimental data were pseudo-second order and Elovich and the kinetics model was the dual-site Langmuir-Freundlich. Both models suggest that the adsorption occurs by the chemical nature of the surface and in the pores of the energetically heterogeneous composite. The PAni/MWCNT presented an adsorption capacity of 221.2 mg g -1 , a very good value when compared with the literature and can be used to remove pharmaceuticals from aqueous environments. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Iron oxide functionalized graphene nano-composite for dispersive solid phase extraction of chemical warfare agents from aqueous samples.

    Chinthakindi, Sridhar; Purohit, Ajay; Singh, Varoon; Tak, Vijay; Goud, D Raghavender; Dubey, D K; Pardasani, Deepak

    2015-05-15

    Present study deals with the preparation and evaluation of graphene based magnetic nano-composite for dispersive solid phase extraction of Chemical Weapons Convention (CWC) relevant chemicals from aqueous samples. Nano-composite, Fe3O4@SiO2-G was synthesized by covalently bonding silica coated Fe3O4 onto the graphene sheets. Nerve agents (NA), Sulfur mustard (SM) and their non-toxic environmental markers were the target analytes. Extraction parameters like amount of sorbent, extraction time and desorption conditions were optimized. Dispersion of 20 milligram of sorbent in 200mL of water sample for 20min. followed by methanol/chloroform extraction produced average to good recoveries (27-94%) of targeted analytes. Recoveries of real agents exhibited great dependency upon sample pH and ionic strength. Sarin produced maximum recovery under mild acidic conditions (56% at pH 5) while VX demanded alkaline media (83% at pH 9). Salts presence in the aqueous samples was found to be advantageous, raising the recoveries to as high as 94% for SM. Excellent limits of detection (LOD) for sulphur mustard and VX (0.11ngmL(-1) and 0.19ngmL(-1) respectively) proved the utility of the developed method for the off-site analysis of CWC relevant chemicals. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Flexible Black-Phosphorus Nanoflake/Carbon Nanotube Composite Paper for High-Performance All-Solid-State Supercapacitors.

    Yang, Bingchao; Hao, Chunxue; Wen, Fusheng; Wang, Bochong; Mu, Congpu; Xiang, Jianyong; Li, Lei; Xu, Bo; Zhao, Zhisheng; Liu, Zhongyuan; Tian, Yongjun

    2017-12-27

    We proposed a simple route for fabrication of the flexible BP nanoflake/carbon nanotube (CNT) composite paper as flexible electrodes in all-solid-state supercapacitors. The highly conductive CNTs not only play a role as active materials but also increase conductivity of the hybrid electrode, enhance electrolyte shuttling and prevent the restacking between BP nanoflakes. The fabricated flexible all-solid-state supercapacitor (ASSP) device at the mass proportion of BP/CNTs 1:4 was found to deliver the highest volumetric capacitance of up to 41.1 F/cm 3 at 0.005 V/s, superior to the ASSP based on the bare graphene or BP. The BP/CNTs (1:4) device delivers a rapid charging/discharging up to 500 V/s, which exhibits the characteristic of a high power density of 821.62 W/cm 3 , while having outstanding mechanical flexibility and high cycling stability over 10 000 cycles (91.5% capacitance retained). Moreover the BP/CNTs (1:4) ASSP device still retains large volumetric capacitance (35.7 F/cm 3 at the scan rate of 0.005 V/s) even after 11 months. In addition, the ASSP of BP/CNTs (1:4) exhibits high energy density of 5.71 mWh/cm 3 and high power density of 821.62 W/cm 3 . As indicated in our work, the strategy of assembling stacked-layer composites films will open up novel possibility for realizing BP and CNTs in new-concept thin-film energy storage devices.

  16. Performance assessment of MCM-48 ceramic composite membrane by separation of AlCl3 from aqueous solution.

    Kumar Basumatary, Ashim; Kumar Ghoshal, Aloke; Pugazhenthi, G

    2016-12-01

    Three dimensional ordered mesoporous MCM-48 membrane was fabricated on a circular shaped ceramic support by in-situ hydrothermal method. The synthesized MCM-48 powder and MCM-48 ceramic composite membrane were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM). The porosity and pore size of the composite membrane are reduced considerably by the deposition of MCM-48 on the support. The formation of MCM-48 is verified by the XRD analysis. Three stepwise mechanisms for surfactant removal are observed by TGA analysis. FESEM images clearly signify the deposition of MCM-48 on the ceramic support. The pure water flux of the support and MCM-48 composite membrane is found to be 3.63×10 -6 and 4.18×10 -8 m 3 /m 2 skPa, respectively. The above prepared MCM-48 ceramic composite membrane is employed for the removal of AlCl 3 from aqueous solution and the highest rejection of 81% is obtained at an applied pressure of 276kPa with salt concentration of 250ppm. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Potentiometric titration for determining the composition and stability of metal(II) alginates and pectinates in aqueous solutions

    Kaisheva, N. Sh.; Kaishev, A. Sh.

    2015-07-01

    The compositions and stabilities of Cu2+, Mn2+, Pb2+, Ca2+, Zn2+, Cd2+, Co2+, and Ni2+ alginates and pectinates are determined in aqueous solutions via titrimetry and potentiometry with calculations performed using Bjerrum's method, the curve intersection technique, and the equilibrium shift method. It is found that the interaction between Cu2+ and polyuronides is a stepwise process and, depending on the ligand concentration and the method of determination, Cu2+ alginate can be characterized by its ML, ML2, and ML3 compositions (where M is the metal ion and L is the structural unit of polyuronide) and stability constants logβ = 2.65, 5.00-5.70, and 7.18-7.80, respectively. The compositions of Cu2+ pectinates are ML and ML2 with logβ = 3.00 and 7.64-7.94, respectively. It is concluded that Pb2+, Ca2+, Mn2+, Zn2+, Cd2+, Co2+, and Ni2+ ions form only alginates and pectinates of ML2 composition with logβ values of 3.45 (Pb2+ alginate), 2.20 (Ca2+ alginate), 1.06 (Mn2+ alginate), 3.51 (Pb2+ pectinate), 2.35 (Ca2+ pectinate), and 1.24 (Mn2+ pectinate). The pectinates are shown to be more stable than the alginates, the most stable compounds being those formed by polyuronides and Cu2+. The least stable are those with Mn2+.

  18. Rationally Designed, Multifunctional Self-Assembled Nanoparticles for Covalently Networked, Flexible and Self-Healable Superhydrophobic Composite Films.

    Lee, Yujin; You, Eun-Ah; Ha, Young-Geun

    2018-03-21

    For constructing bioinspired functional films with various superhydrophobic functions, including self-cleaning, anticorrosion, antibioadhesion, and oil-water separation, hydrophobic nanomaterials have been widely used as crucial structural components. In general, hydrophobic nanomaterials, however, cannot form strong chemical bond networks in organic-inorganic hybrid composite films because of the absence of chemically compatible binding components. Herein, we report the rationally designed, multifunctional self-assembled nanoparticles with tunable functionalities of covalent cross-linking and hydrophobicity for constructing three-dimensionally interconnected superhydrophobic composite films via a facile solution-based fabrication at room temperature. The multifunctional self-assembled nanoparticles allow the systematic control of functionalities of composite films, as well as the stable formation of covalently linked superhydrophobic composite films with excellent flexibility (bending radii of 6.5 and 3.0 mm, 1000 cycles) and self-healing ability (water contact angle > 150°, ≥10 cycles). The presented strategy can be a versatile and effective route to generating other advanced functional films with covalently interconnected composite networks.

  19. Nanocellulose coupled flexible polypyrrole@graphene oxide composite paper electrodes with high volumetric capacitance

    Wang, Zhaohui; Tammela, Petter; Strømme, Maria; Nyholm, Leif

    2015-02-01

    A robust and compact freestanding conducting polymer-based electrode material based on nanocellulose coupled polypyrrole@graphene oxide paper is straightforwardly prepared via in situ polymerization for use in high-performance paper-based charge storage devices, exhibiting stable cycling over 16 000 cycles at 5 A g-1 as well as the largest specific volumetric capacitance (198 F cm-3) so far reported for flexible polymer-based electrodes.A robust and compact freestanding conducting polymer-based electrode material based on nanocellulose coupled polypyrrole@graphene oxide paper is straightforwardly prepared via in situ polymerization for use in high-performance paper-based charge storage devices, exhibiting stable cycling over 16 000 cycles at 5 A g-1 as well as the largest specific volumetric capacitance (198 F cm-3) so far reported for flexible polymer-based electrodes. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07251k

  20. Use of Composite Sorbents for the Removal of Copper (II ions from Aqueous Solution

    Rebecca Oyedoyin Adeeyo

    2015-01-01

    Full Text Available Composite adsorbents are synthesized from two or more materials with different chemical and physical properties in order to increase their selectivity and the reusability. Researchers have developed and applied several novel composite materials for enhancing the removal of heavy metal. In this review, extensive list of composites developed via advanced technologies with specified characteristics for the removal of Cu (II ion are discussed. Emphases on their adsorption capacities, reusability, desorption and regeneration with improved mechanical strengths are presented. Conclusively, prospects and other challenges to be checked and addressed in future are outlined.

  1. Removal of boron from aqueous solution using magnesite and bentonite clay composite

    Masindi, Vhahangwele

    2015-03-01

    Full Text Available The removal of boron from industrial effluents using the composite was studied in batch equilibration technique. The effects of equilibration time, adsorbent dosage, concentration and pH on removal of boron were investigated. The experiments...

  2. Sorption of technetium on composite chitosan-hydroxyapatite from aqueous solutions

    Pivarciova, L.; Rosskopfova, O.; Galambos, M.; Rajec, P.

    2013-01-01

    Biomaterials such as natural polymers (chitosan) and hydroxyapatite have an important application in material for bone replacement. Most of chitosan/hydroxyapatite composites are prepared by mixing hydroxyapatite particles with chitosan matrices. Another method of preparation of chitosan/hydroxyapatite composite is in-situ generation of nano-hydroxyapatite in chitosan matrix. The most common biomaterial used in the past years in hard tissue regeneration was hydroxyapatite, owing to its properties as biocompatibility, bioactivity, non-toxicity, non-immunogenicity etc. Chitosan is a polyaminosacharide, partially deacetylated product of chitin. Chitosan can be used in combination with other materials to enhance bone growth such as bone filling paste. The aims of this work were: the influence of the contact time on sorption of pertechnate anions on chitosan/hydroxyapatite composites; the effect of pH on sorption of pertechnate anions on chitosan/hydroxyapatite composites; the effect of foreign ions on sorption of pertechnate anions on chitosan/hydroxyapatite composites. The author concluded: the percentage of technetium sorption after 1 hour of contact time was > 97 %. In the initial pH range of 2.9-10.2, the percentage of technetium sorption on chitosan/hydroxyapatite composites CH/HA(A), CH/HA(B), CH/HA 30:70, ZCH was > 98 % and on CH/HA 50:50 was > 94%. The competition effect of Fe 2+ towards TcO 4 :- sorption is stronger than competition effect of other observed cations for all examined composites with the same weight ratio. The percentage of the technetium sorption was the same for all composites with the weight ratio of 30:70. (authors)

  3. Application of composite materials based on various extractants for isolation of lanthanides(III) nitrates from multicomponent aqueous solutions

    Kopyrin, A.A.; Pyartman, A.K.; Kesnikov, V.A.; Pleshkov, M.A.; Exekov, M.H.

    1999-01-01

    In present work we obtained samples of composite materials mentioned containing tributylphosphate (TBP) and trialkylmethylammonium nitrate (TAMAN). Extraction of lanthanides(III) nitrates of cerium group from multicomponent aqueous solutions by means of these materials was studied. Some systems with different concentration of sodium nitrate up to 5 mol/l and the same systems containing additions of sodium chloride or sulfate along with sodium nitrate was investigated, isotherm of extraction being obtained for all cases. Also we compared in identical conditions extraction process when liquid extractants were used and process with composite materials. It was found that traditional extraction systems and systems based on composite extractants demonstrated almost the same extraction properties in respect to lanthanides(III) nitrates. Extraction isotherms observed in identical conditions and being shown in the same coordinates had no difference with taking into account errors of experiment. This fact allow to use the same mathematical model for those systems. For systems studied it was generated mathematical model that is able to describe extraction process when component concentration vary in wide range, with assumption being used that ratio activity coefficients in organic phase stay constant. (authors)

  4. Kinetic Studies For the Removal of UO22+ and Pb2+ Ions From Aqueous Solution Using Zirconia Composite Material

    Sharaf El-Deen, G.E.

    2008-01-01

    Zirconia composite material was chemically synthesized previously and prepared by applying the sol-gel polymeric route using MgO as a stabilizer. The prepared composite material was characterized using various techniques: x-ray fluorescence (XRF), scanning electron microscope (SEM), differential thermal analysis and thermogravimetric analysis (DTA-TG), x-ray diffraction (XRD) and surface area using the BET-method. The sorption removal of UO 2 2+ and Pb 2+ ions from aqueous waste solution by zirconia composite material using batch technique was investigated. The sorption was carried out as a function of ph, particle size, shaking time and temperature. In this work, a comparison of kinetic models applied to the sorption process of each ion was evaluated for the pseudo first-order, the pseudo second-order, intra particle diffusion and homogeneous particle diffusion kinetic models, respectively. The results showed that the homogeneous particle diffusion model (HPDM) best correlate the experimental rate data and the numerical values of the rate constants and particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy (Ε a ) and thermodynamic parameters of free energy (δ G * ), enthalpy (δ H * ) and entropy (δ S * ) of activation were also computed from the linearized form of Arrhenius equation

  5. Fabrication of Si Nanoparticles@Carbon Fibers Composites from Natural Nanoclay as an Advanced Lithium-Ion Battery Flexible Anode

    Sainan Liu

    2018-04-01

    Full Text Available In this paper, a cost-effective strategy for fabricating silicon-carbon composites was designed to further improve the electrochemical performance and commercialization prospects of Si anodes for lithium-ion batteries (LIBs. Silicon-carbon fibers (CFs were prepared by loading Si nanoparticles (SiNPs on interconnected carbon fibers via an electrospinning technique (SiNPs@CFs. The Si nanoparticles were obtained by the reduction reaction of natural clay minerals. As a flexible anode for LIBs, the SiNPs@CFs anode demonstrated a reversible capacity of 1238.1 mAh·g−1 and a capacity retention of 77% after 300 cycles (in contrast to the second cycle at a current density of 0.5 A·g−1. With a higher current density of 5.0 A·g−1, the electrode showed a specific capacity of 528.3 mAh·g−1 after 1000 cycles and exhibited a superior rate capability compared to Si nanoparticles. The excellent electrochemical properties were attributed to the construction of flexible electrodes and the composite comprising carbon fibers, which lessened the volume expansion and improved the conductivity of the system.

  6. Flexible one-dimensional carbon-selenium composite nanofibers with superior electrochemical performance for Li-Se/Na-Se batteries

    Zeng, Linchao; Wei, Xiang; Wang, Jiaqing; Jiang, Yu; Li, Weihan; Yu, Yan

    2015-05-01

    A facile strategy is developed to synthesis selenium/carbon composites (Se@CNFs-CNT) by co-heating Se powder and electrospun Polyacrylonitrile (PAN)-CNT nanofibers at 600°Cin a sealed vessel. The Se molecules are chemically bonded and physical encapsulated by carbonized PAN-CNT composite (CNFs-CNT), which leads to prevent the dissolution of polyselenide intermediates in carbonate based electrolyte. When directly used as flexible free-standing cathode material for Li-Se batteries in low cost carbonate-based electrolyte, the Se@CNFs-CNT electrode exhibits improved cyclability (517 mAh g-1 after 500 cycles at 0.5 A g-1) and rate capability (485 mAh g-1 at 1 A g-1). Moreover, when tested as sodium batteries, it maintains a reversible capacity of 410 mAh g-1 after 240 cycles at 0.5 A g-1. The superior electrochemical performance (especially at high rates) of Se@CNFs-CNT is attributed to synergistic effect of the additive of CNT, the well confine of Se in the CNFs-CNT matrix through chemical bonding and the 3D interconnected carbon nanofibers (CNFs). This simple yet efficient process thus provides a promising route towards fabrication of a variety of high performance flexible Li-Se and Na-Se batteries.

  7. Ink-jet printed porous composite LiFePO4 electrode from aqueous suspension for microbatteries

    Delannoy, P.-E.; Riou, B.; Brousse, T.; Le Bideau, J.; Guyomard, D.; Lestriez, B.

    2015-08-01

    This work demonstrates ink-jet printed LiFePO4-based composite porous electrodes for microbattery application. As binder and dispersant, we found that aqueous inks with more suitable rheological properties with respect to ink-jet printing are prepared with the low molecular weight poly-acrylic-co-maleic acid copolymer, rather than with the carboxymethyl cellulose standard binder of the lithium-ion technology. The ink-jet printed thin and porous electrode shows very high rate charge/discharge behavior, both in LiPF6/ethylene carbonate-dimethyl carbonate (LP30) and lithium bis(trifluoromethane)sulfonylimide salt (Li-TFSI) in N-methyl-N-propylpyrrolidinium bis(trifluoromethane)suflonylimide ionic liquid (PYR13-TFSI) electrolytes, as well as good cyclability.

  8. Flexible thermoplastic composite of Polyvinyl Butyral (PVB and waste of rigid Polyurethane foam

    Marilia Sônego

    2015-04-01

    Full Text Available This study reports the preparation and characterization of composites with recycled poly(vinyl butyral (PVB and residue of rigid polyurethane foam (PUr, with PUr contents of 20, 35 and 50 wt %, using an extruder equipped with a Maillefer single screw and injection molding. The components of the composites were thermally characterized using differential scanning calorimetry (DSC and thermogravimetry. The composites were evaluated by melt flow index (MFI, tensile and hardness mechanical tests and scanning electron microscopy (SEM. Tg determined by DSC of PVB sample (53 °C indicated the presence of plasticizer (Tg of pure PVB is 70 °C. MFI of the composites indicated a viscosity increase with the PUr content and, as the shear rate was held constant during injection molding, higher viscosities promoted higher shear stresses in the composites, thereby causing breaking or tearing of the PUr particles. The SEM micrographs showed low adhesion between PVB and PUr and the presence of voids, both inherent in the rigid foam and in the interphase PVB-PUr. The SEM micrographs also showed that PVB/PUr (50/50 composite exhibited the smallest particle size and a more homogeneous and compact structure with fewer voids in the interface. The stiffness of the composites increases with addition of the PUr particles, as evidenced in the mechanical tests.

  9. Formation and composition of adsorbates on hydrophobic carbon surfaces from aqueous laccase-maltodextrin mixture suspension

    Corrales Ureña, Yendry Regina, E-mail: yendry386@hotmail.com [UNESP São Paulo State University, Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, Bauru, São Paulo (Brazil); Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Strasse 12, 28359 Bremen (Germany); Lisboa-Filho, Paulo Noronha [UNESP São Paulo State University, Av. Eng. Luiz Edmundo Carrijo Coube, 14-01, Bauru, São Paulo (Brazil); Szardenings, Michael [Fraunhofer Institute for Cell Therapy and Immunology IZI, Perlickstrasse 1, 04103 Leipzig (Germany); Gätjen, Linda; Noeske, Paul-Ludwig Michael; Rischka, Klaus [Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Strasse 12, 28359 Bremen (Germany)

    2016-11-01

    Highlights: • Less than 10 nm layer formed on carbon based materials composed by laccase and maltodextrin. • Improvement of the wettability of carbon based materials. • A protein-polysaccharide biofilm layer formation at solid liquid interface. • Stable layers formed under buffer and water rinsing. - Abstract: A robust procedure for the surface bio-functionalization of carbon surfaces was developed. It consists on the modification of carbon materials in contact with an aqueous suspension of the enzyme laccase from Trametes versicolor and the lyophilization agent maltodextrin, with the pH value adjusted close to the isoelectric point of the enzyme. We report in-situ investigations applying Quartz Crystal Microbalance with Dissipation (QCM-D) for carbon-coated sensor surfaces and, moreover, ex-situ measurements with static contact angle measurements, X-ray Photoelectron Spectroscopy (XPS) and Scanning Force Microscopy (SFM) for smooth Highly Oriented Pyrolytic Graphite (HOPG) substrates, for contact times between the enzyme formulation and the carbon material surface ranging from 20 s to 24 h. QCM-D studies reveals the formation of rigid layer of biomaterial, a few nanometers thin, which shows a strongly improved wettability of the substrate surface upon contact angle measurements. Following spectroscopic characterization, these layers are composed of mixtures of laccase and maltodextrin. The formation of these adsorbates is attributed to attractive interactions between laccase, the maltodextrin-based lyophilization agent and the hydrophobic carbon surfaces; a short-term contact between the aqueous laccase mixture suspension and HOPG surfaces is shown to merely result in de-wetting patterns influencing the results of contact angle measurements. The new enzyme-based surface modification of carbon-based materials is suggested to be applicable for the improvement of not only the wettability of low energy substrate surfaces with fluid formulations like coatings

  10. Highly Stable and Flexible Pressure Sensors with Modified Multi-Walled Carbon Nanotube/Polymer Composites for Human Monitoring.

    He, Yin; Ming, Yue; Li, Wei; Li, Yafang; Wu, Maoqi; Song, Jinzhong; Li, Xiaojiu; Liu, Hao

    2018-04-26

    A facile method for preparing an easy processing, repeatable and flexible pressure sensor was presented via the synthesis of modified multi-walled carbon nanotubes (m-MWNTs) and polyurethane (PU) films. The surface modification of multi-walled carbon nanotubes (MWNTs) simultaneously used a silane coupling agent (KH550) and sodium dodecyl benzene sulfonate (SDBS) to improve the dispersibility and compatibility of the MWNTs in a polymer matrix. The electrical property and piezoresistive behavior of the m-MWNT/PU composites were compared with raw multi-walled carbon nanotube (raw MWNT)/PU composites. Under linear uniaxial pressure, the m-MWNT/PU composite exhibited 4.282%kPa −1 sensitivity within the pressure of 1 kPa. The nonlinear error, hysteresis error and repeatability error of the piezoresistivity of m-MWNT/PU decreased 9%, 16.72% and 54.95% relative to raw MWNT/PU respectively. Therefore, the piezoresistive response of m-MWNT/PU had better stability than that of raw MWNT/PU composites. The m-MWNT/PU sensors could be utilized in wearable devices for body movement detection, monitoring of respiration and pressure detection in garments.

  11. Inverse hydrochemical models of aqueous extracts tests

    Zheng, L.; Samper, J.; Montenegro, L.

    2008-10-10

    Aqueous extract test is a laboratory technique commonly used to measure the amount of soluble salts of a soil sample after adding a known mass of distilled water. Measured aqueous extract data have to be re-interpreted in order to infer porewater chemical composition of the sample because porewater chemistry changes significantly due to dilution and chemical reactions which take place during extraction. Here we present an inverse hydrochemical model to estimate porewater chemical composition from measured water content, aqueous extract, and mineralogical data. The model accounts for acid-base, redox, aqueous complexation, mineral dissolution/precipitation, gas dissolution/ex-solution, cation exchange and surface complexation reactions, of which are assumed to take place at local equilibrium. It has been solved with INVERSE-CORE{sup 2D} and been tested with bentonite samples taken from FEBEX (Full-scale Engineered Barrier EXperiment) in situ test. The inverse model reproduces most of the measured aqueous data except bicarbonate and provides an effective, flexible and comprehensive method to estimate porewater chemical composition of clays. Main uncertainties are related to kinetic calcite dissolution and variations in CO2(g) pressure.

  12. Arsenic removal from aqueous solutions using Fe3O4-HBC composite: effect of calcination on adsorbents performance.

    Shams Ali Baig

    Full Text Available The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C and environment (air and nitrogen were investigated for the adsorptive removal of As(V and As(III from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4 via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2>Fe3O4-HBC (uncalcined>Fe3O4-HBC-400°C(N2>Fe3O4-HBC-400°C(air>Fe3O4-HBC-1000°C(air and the maximum As(V and As(III adsorption capacities were found to be about 3.35 mg g(-1 and 3.07 mg g(-1, respectively. The adsorption of As(V and As(III remained stable in a wider pH range (4-10 using Fe3O4-HBC-1000°C(N2. Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99 rather than pseudo-first-order kinetics model. The adsorption of As(V and As(III onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher strongly inhibited As(V and As(III removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.

  13. Arsenic removal from aqueous solutions using Fe3O4-HBC composite: effect of calcination on adsorbents performance.

    Baig, Shams Ali; Sheng, TianTian; Sun, Chen; Xue, XiaoQin; Tan, LiSha; Xu, XinHua

    2014-01-01

    The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4) via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH) was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2)>Fe3O4-HBC (uncalcined)>Fe3O4-HBC-400°C(N2)>Fe3O4-HBC-400°C(air)>Fe3O4-HBC-1000°C(air) and the maximum As(V) and As(III) adsorption capacities were found to be about 3.35 mg g(-1) and 3.07 mg g(-1), respectively. The adsorption of As(V) and As(III) remained stable in a wider pH range (4-10) using Fe3O4-HBC-1000°C(N2). Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99) rather than pseudo-first-order kinetics model. The adsorption of As(V) and As(III) onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher) strongly inhibited As(V) and As(III) removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.

  14. Influence of the composition of the aqueous phase on the behavior of the system FeCl3-HCl-DPE

    Ramirez, F. de M.; Jimenez-Reyes, M.

    1981-07-01

    We studied the influence of the aqueous phase composition upon an extraction system in which, at room temperature (20 0 C +- 3 0 C) using the dissolvents FeCl 3 -HCl-di-isopropyl ether the third phase phenomena is present after one minute of agitation. Our results showed that principally the hydrochloric acid dissolvent produced each of the three phases at given concentration levels as well as determined the nature of the chemical composition in each phase. (author)

  15. Piezoelectric Flexible LCP-PZT Composites for Sensor Applications at Elevated Temperatures

    Tolvanen, Jarkko; Hannu, Jari; Juuti, Jari; Jantunen, Heli

    2018-03-01

    In this paper fabrication of piezoelectric ceramic-polymer composites is demonstrated via filament extrusion enabling cost-efficient large-scale production of highly bendable pressure sensors feasible for elevated temperatures. These composites are fabricated by utilizing environmentally resistant and stable liquid crystal polymer matrix with addition of lead zirconate titanate at loading levels of 30 vol%. These composites, of approximately 0.99 mm thick and length of > 50 cm, achieved excellent bendability with minimum bending radius of 6.6 cm. The maximum piezoelectric coefficients d33 and g33 of the composites were > 14 pC/N and > 108 mVm/N at pressure < 10 kPa. In all cases, the piezoelectric charge coefficient (d33) of the composites decreased as a function of pressure. Also, piezoelectric coefficient (d33) further decreased in the case of increased frequency press-release cycle sand pre-stress levels by approximately 37-50%. However, the obtained results provide tools for fabricating novel piezoelectric sensors in highly efficient way for environments with elevated temperatures.

  16. Lignocellulosic composites prepared utilizing aqueous alkaline/urea solutions with cold temperatures

    Lignocellulosic composites (LCs) were fabricated by partially dissolving cotton to create a matrix that was reinforced with Osage orange wood (OOW) particles and/or Blue agave fibers (AF). LCs were composed of 15-35% cotton matrix: 65-85% OWW/AF reinforcement. The matrix was produced by soaking cott...

  17. Synthesis of some Ferromagnetic Composite Resins and their Metal Removal Characteristics in Aqueous Solutions

    Sheha, R.R.; EI-Zahhar, A.A.

    2008-01-01

    In this study, a procedure for synthesis of new organic-inorganic magnetic composite resins was established. The procedure was based upon immobilization of magnetite as a ferromagnetic material within the polymeric (poly(acrylic acid acrylonitrile) and IRC-120) ion exchange resins. The produced magnetic resins were evaluated as sorbents for CI(VI). The factors influencing the sorption of Cr(Vl), e.g., ph, equilibrium time, initial concentration and temperature were studied. The sorption process was very fast initially and maximum sorption was achieved within 3 h at ph 5.1. Thc kinetics of the system have been evaluated with pseudo first order model, second order model, Elovich equation, intra-particle diffusion model and liquid film diffusion model. Chromium interaction with composite particles followed second-order kinetics with a correlation coefficient extremely high and closer to unity and rate constant (k s ) has the values 1.68 x 10 -4 and 1.9 x 10 -4 g/mg min for IRC-120-P AN-magnetite and P(AA-AN)-magnetite composites, respectively. The values of equilibrium sorption capacity (q e ) are consistent with the modeled data and attain the range 893 - 951 mg/g. Kinetically, both pore diffusion and film diffusion are participating in ruling the diffusion of CI(VI) ions. The sorption data gave good fits with Temkin and Flory-Huggins isotherm models. The isotherm parameters related to the heat of sorption are in the range 8-16 kJ mol -1 which is the range of bonding energy for ion exchange interactions and so suggest an ion exchange mechanism for removal of CI(VI) by the composite sorbents. The adsorption process was exothermic with δH in the range of -73 to -97 kJ/mol. The negative values of Gibbs free energy confirm the feasibility and the spontaneous nature of removal of CI(VI) with these novel composites

  18. Effective adsorption of malachite green using magnetic barium phosphate composite from aqueous solution

    Zhang, Fan; Wei, Zhong; Zhang, Wanning; Cui, Haiyan

    2017-07-01

    Magnetic Ba3(PO4)2/Fe3O4-nanoparticle (called BPFN) was prepared, characterized, and developed as a low-cost adsorbent for malachite green (MG) from aqueous solution. Factors such as adsorption temperature, pH of solution, dosage of adsorbent, adsorption kinetics and isotherms were investigated. The maximum adsorption capacity obtained in this work was 1639 mg g- 1 at 45 °C and pH 6. The adsorption process fitted the pseudo-first-order kinetic model and Langmuir isotherm model. Evidences from zeta potential, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) data revealed that the adsorption process was driven by electrostatic attraction, the interaction between Lewis base sbnd N(CH3)2 in MG and Lewis acid Ba sites of BPFN. In addition, the BPFN could be easily regenerated by a magnet and the adsorption capacity maintained at 70% after five cycles. The present study suggests that the BPFN had high potential of removing MG from wastewater.

  19. Understanding of electrochemical and structural changes of polypyrrole/polyethylene glycol composite films in aqueous solution

    Pirvu, Cristian; Manole, Claudiu Constantin; Stoian, Andrei Bogdan; Demetrescu, Ioana

    2011-01-01

    Highlights: → Electrochemical monitoring of PPy and PPy-PEG films over immersion time. → Electrochemical and surface analysis showed that PEG improves the stability of PPy films. → Mott-Schottky analysis reveals p-type conductance for both films. → In situ AFM analysis sustains electrochemical behaviour. → A model of PPy and PPy-PEG films behaviour during immersion was elaborated. - Abstract: Electrochemical monitoring of electrical and structural changes of both PPy and PPy-PEG films electrochemical deposited, in order to highlight if the structural stability offered by PEG has an influence on electrical properties and stability in aqueous solution over immersion time was investigated. Electrochemical analysis suggests that PPy-PEG film inserts cations easier than PPy film for a short immersion time probably due to ability of PEG to form complexes with metal cations. The FTIR spectra showed that the PEG incorporation decreases the rate of PPy overoxidation probably by restraining the electron release and by rendering O 2 inaccessible to PPy. Mott-Schottky analysis based on capacitance measurement reveal p-type conductance for both films. The in situ AFM analysis sustains electrochemical behaviour and has permitted elaboration of a model of PPy and PPy-PEG films behaviour during immersion in testing solution.

  20. Understanding of electrochemical and structural changes of polypyrrole/polyethylene glycol composite films in aqueous solution

    Pirvu, Cristian, E-mail: c_pirvu@chim.pub.ro [University Polytechnic of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-7 Polizu, 011061 Bucharest (Romania); Manole, Claudiu Constantin; Stoian, Andrei Bogdan; Demetrescu, Ioana [University Polytechnic of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-7 Polizu, 011061 Bucharest (Romania)

    2011-11-30

    Highlights: > Electrochemical monitoring of PPy and PPy-PEG films over immersion time. > Electrochemical and surface analysis showed that PEG improves the stability of PPy films. > Mott-Schottky analysis reveals p-type conductance for both films. > In situ AFM analysis sustains electrochemical behaviour. > A model of PPy and PPy-PEG films behaviour during immersion was elaborated. - Abstract: Electrochemical monitoring of electrical and structural changes of both PPy and PPy-PEG films electrochemical deposited, in order to highlight if the structural stability offered by PEG has an influence on electrical properties and stability in aqueous solution over immersion time was investigated. Electrochemical analysis suggests that PPy-PEG film inserts cations easier than PPy film for a short immersion time probably due to ability of PEG to form complexes with metal cations. The FTIR spectra showed that the PEG incorporation decreases the rate of PPy overoxidation probably by restraining the electron release and by rendering O{sub 2} inaccessible to PPy. Mott-Schottky analysis based on capacitance measurement reveal p-type conductance for both films. The in situ AFM analysis sustains electrochemical behaviour and has permitted elaboration of a model of PPy and PPy-PEG films behaviour during immersion in testing solution.

  1. Microcavity-Free Broadband Light Outcoupling Enhancement in Flexible Organic Light-Emitting Diodes with Nanostructured Transparent Metal-Dielectric Composite Electrodes.

    Xu, Lu-Hai; Ou, Qing-Dong; Li, Yan-Qing; Zhang, Yi-Bo; Zhao, Xin-Dong; Xiang, Heng-Yang; Chen, Jing-De; Zhou, Lei; Lee, Shuit-Tong; Tang, Jian-Xin

    2016-01-26

    Flexible organic light-emitting diodes (OLEDs) hold great promise for future bendable display and curved lighting applications. One key challenge of high-performance flexible OLEDs is to develop new flexible transparent conductive electrodes with superior mechanical, electrical, and optical properties. Herein, an effective nanostructured metal/dielectric composite electrode on a plastic substrate is reported by combining a quasi-random outcoupling structure for broadband and angle-independent light outcoupling of white emission with an ultrathin metal alloy film for optimum optical transparency, electrical conduction, and mechanical flexibility. The microcavity effect and surface plasmonic loss can be remarkably reduced in white flexible OLEDs, resulting in a substantial increase in the external quantum efficiency and power efficiency to 47.2% and 112.4 lm W(-1).

  2. Electrochemical characteristics of the reduced graphene oxide/carbon nanotube/polypyrrole composites for aqueous asymmetric supercapacitors

    Peng, Yu-Jung; Wu, Tzu-Ho; Hsu, Chun-Tsung; Li, Shin-Ming; Chen, Ming-Guan; Hu, Chi-Chang

    2014-12-01

    Polypyrrole (PPy) has been polymerized onto reduced graphene oxide/carbon nanotube (rGO/CNT) to form an rGO/CNT/PPy composite using the chemical oxidation method. The electrochemical characteristics of the above composite in various aqueous electrolytes are systematically compared for the asymmetric supercapacitor application. The electrochemical characteristics of rGO/CNT/PPy in the electrolytes containing K+ show improved reversibility and higher stability. Introducing XC-72 in preparing the electrode has been found to enhance the specific capacitance and the cycle stability of rGO/CNT/PPy. The charge storage stability of rGO/CNT/PPy + XC-72 in various potential windows has been evaluated through the potential bias stress test. An asymmetric supercapacitor (ASC) with a positive electrode of Mn3O4 and a negative electrode of rGO/CNT/PPy + XC-72 is successfully demonstrated, which shows specific energy and power of 14. Wh kg-1 and 6.62 kW kg-1 with a cell voltage of 1.6 V. This ASC with a cell voltage of 1.6 V shows excellent charge-discharge cycle stability and ideal capacitive behavior in NaNO3 even after the application of 3250 charge-discharge cycles.

  3. Enhanced adsorbability and photocatalytic activity of TiO2-graphene composite for polycyclic aromatic hydrocarbons removal in aqueous phase.

    Bai, Hongzhen; Zhou, Jun; Zhang, Hongjian; Tang, Guping

    2017-02-01

    Photodegradation via titanium dioxide (TiO 2 ) has been used to remove polycyclic aromatic hydrocarbons (PAHs) from environmental media broadly. In this study, a series of TiO 2 -graphene composites (P25-GR) with different GR weight ratios were synthesized via hydrothermal reaction of graphene oxide (GO) and P25. Their structures were characterized and the proprieties were tested in aqueous phase. Phenanthrene (PHE), fluoranthene (FLAN), and benzo[a]pyrene (BaP) were selected as models of PAHs. The experiment indicated that P25-2.5%GR exhibited enhancement in both adsorption and photodegradation, ∼80% of PAHs were removed after 2h photocatalysis. The influence of photodegradation rate was studied, including PAHs initial concentration and pH. Aromatic intermediates were identified during the reaction process and the degradation pathways were portrayed. This work explored the enhanced photocatalysis performance was attributed to the PAH-selective adsorbability and the strong electron transfer ability of the composite. The analysis of the degradation intermediates confirmed that the reaction proceeded with the formation of free radicals, leading to the gradual PAH mineralization. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Analyzing multivariate survival data using composite likelihood and flexible parametric modeling of the hazard functions

    Nielsen, Jan; Parner, Erik

    2010-01-01

    In this paper, we model multivariate time-to-event data by composite likelihood of pairwise frailty likelihoods and marginal hazards using natural cubic splines. Both right- and interval-censored data are considered. The suggested approach is applied on two types of family studies using the gamma...

  5. Core-Shell Composite Fibers for High-Performance Flexible Supercapacitor Electrodes.

    Lu, Xiaoyan; Shen, Chen; Zhang, Zeyang; Barrios, Elizabeth; Zhai, Lei

    2018-01-31

    Core-shell nanofibers containing poly(acrylic acid) (PAA) and manganese oxide nanoparticles as the core and polypyrrole (PPy) as the shell were fabricated through electrospinning the solution of PAA and manganese ions (PAA/Mn 2+ ). The obtained nanofibers were stabilized by Fe 3+ through the interaction between Fe 3+ ions and carboxylate groups. Subsequent oxidation of Mn 2+ by KMnO 4 produced uniform manganese dioxide (MnO 2 ) nanoparticles in the fibers. A PPy shell was created on the fibers by immersing the fibers in a pyrrole solution where the Fe 3+ ions in the fiber polymerized the pyrrole on the fiber surfaces. In the MnO 2 @PAA/PPy core-shell composite fibers, MnO 2 nanoparticles function as high-capacity materials, while the PPy shell prevents the loss of MnO 2 during the charge/discharge process. Such a unique structure makes the composite fibers efficient electrode materials for supercapacitors. The gravimetric specific capacity of the MnO 2 @PAA/PPy core-shell composite fibers was 564 F/g based on cyclic voltammetry curves at 10 mV/s and 580 F/g based on galvanostatic charge/discharge studies at 5 A/g. The MnO 2 @PAA/PPy core-shell composite fibers also present stable cycling performance with 100% capacitance retention after 5000 cycles.

  6. Improving the thermal dimensional stability of flexible polymer composite backing materials for ultrasound transducers

    State, M.; Brands, P.J.; Vosse, van de F.N.

    2010-01-01

    Novel ultrasound backing materials based on polymer composites with improved dimensional stability and low coefficient of thermal expansion are being developed and analyzed. For this purpose a filled epoxy resin (Stycast1265), a commonly used backing material, was considered reference material and

  7. Photocatalytic polymerization induced by a transparent anatase titania aqueous sol and fabrication of polymer composites

    2010-06-01

    Full Text Available The surface modification of the anatase titania nanoparticles prepared via a controlled nonhydrolytic sol-gel process is achieved by the formation of the bidentate coordination between titania and methacrylic acid (MAA molecules. The in situ photocatalytic polymerization of methyl methacrylate (MMA monomer is initiated by surface modified anatase titania nanoparticles under Xe lamp irradiation. A variety of techniques including differential scanning calorimetry (DSC, thermo-gravimetric analysis (TGA and scanning electron microscopy (SEM are employed to characterize the resulting materials. The glass transition temperatures and the thermal stabilities of polymethyl methacrylate (PMMA composite materials prepared via photocatalytic polymerization are enhanced compared with pure polymer. The partial aggregation of titania nanoparticles in PMMA composite films is derived from the surface polymerization of MMA, which makes the inorganic particles hydrophobic and drives them to the water/oil interfaces.

  8. Fabrication and characterization of a multidirectional-sensitive contact-enhanced inertial microswitch with a electrophoretic flexible composite fixed electrode

    Yang, Zhuoqing; Zhu, Bin; Chen, Wenguo; Ding, Guifu; Wang, Hong; Zhao, Xiaolin

    2012-01-01

    A multidirectional-sensitive inertial microswitch with a polymer–metal composite fixed electrode has been designed and fabricated based on surface micromachining in this work. The microswitch mainly consists of a suspended proof mass as a movable electrode and a T-shaped structure on the substrate with maple leaf-like top and cantilevers around the central cylinder as vertical and lateral fixed electrodes. It can sense the applied shock accelerations from any radial direction in the xoy plane and z-axis. The new vertical composite fixed electrode of the switch is completed by electroplating and electrophoretic deposition, which can realize a flexible contact between the electrodes and reduce the bounces and prolong the contact time. As a result, the stability and reliability of the inertial switch could be greatly improved. The fabricated microswitches have been tested and characterized by a standard dropping hammer system. It is shown that the threshold acceleration of the prototype is generally uniform in different sensitive directions in the xoy plane and z-axis, which is about 70 g. The contact time of the microswitch with the composite fixed electrode is ∼110 µs in the vertical direction, which is longer than that (∼65 µs) without a polymer. The test data are in agreement with dynamic finite-element simulation results. (paper)

  9. Development of Chitosan/Bacterial Cellulose Composite Films Containing Nanodiamonds as a Potential Flexible Platform for Wound Dressing

    Fatemeh Ostadhossein

    2015-09-01

    Full Text Available Chitosan/bacterial cellulose composite films containing diamond nanoparticles (NDs with potential application as wound dressing are introduced. Microstructural studies show that NDs are uniformly dispersed in the matrix, although slight agglomeration at concentrations above 2 wt % is seen. Fourier transform infrared spectroscopy reveals formation of hydrogen bonds between NDs and the polymer matrix. X-ray diffraction analysis indicates reduced crystallinity of the polymer matrix in the presence of NDs. Approximately 3.5-fold increase in the elastic modulus of the composite film is obtained by the addition of 2 wt % NDs. The results of colorimetric analysis show that the composite films are transparent but turn to gray-like and semitransparent at high ND concentrations. Additionally, a decrease in highest occupied molecular orbital (HOMO and lowest unoccupied molecular orbital (LUMO gap is also seen, which results in a red shift and higher absorption intensity towards the visible region. Mitochondrial activity assay using L929 fibroblast cells shows that the nanocomposite films are biocompatible (>90% after 24 h incubation. Multiple lamellapodia and cell-cell interaction are shown. The results suggest that the developed films can potentially be used as a flexible platform for wound dressing.

  10. Adsorption of Ni2+ from aqueous solution by magnetic Fe@graphite nano-composite

    Konicki Wojciech

    2016-12-01

    Full Text Available The removal of Ni2+ from aqueous solution by iron nanoparticles encapsulated by graphitic layers (Fe@G was investigated. Nanoparticles Fe@G were prepared by chemical vapor deposition CVD process using methane as a carbon source and nanocrystalline iron. The properties of Fe@G were characterized by X-ray Diffraction method (XRD, High-Resolution Transmission Electron Microscopy (HRTEM, Fourier Transform-Infrared Spectroscopy (FTIR, BET surface area and zeta potential measurements. The effects of initial Ni2+ concentration (1–20 mg L−1, pH (4–11 and temperature (20–60°C on adsorption capacity were studied. The adsorption capacity at equilibrium increased from 2.96 to 8.78 mg g−1, with the increase in the initial concentration of Ni2+ from 1 to 20 mg L−1 at pH 7.0 and 20oC. The experimental results indicated that the maximum Ni2+ removal could be attained at a solution pH of 8.2 and the adsorption capacity obtained was 9.33 mg g−1. The experimental data fitted well with the Langmuir model with a monolayer adsorption capacity of 9.20 mg g−1. The adsorption kinetics was found to follow pseudo-second-order kinetic model. Thermodynamics parameters, ΔHO, ΔGO and ΔSO, were calculated, indicating that the adsorption of Ni2+ onto Fe@G was spontaneous and endothermic in nature.

  11. A Flexible Multifunctional Sensor Based on Carbon Nanotube/Polyurethane Composite

    Slobodian, P.; Říha, Pavel; Benlikaya, R.; Svoboda, P.; Petráš, D.

    2013-01-01

    Roč. 13, č. 10 (2013), s. 4045-4048 ISSN 1530-437X Grant - others:GA MŠk(CZ) ED2.1.00/03.0111; UTB Zlín(CZ) iga/ft/2012/022 Institutional research plan: CEZ:AV0Z20600510 Institutional support: RVO:67985874 Keywords : carbon nanotubes * chemical vapor sensing * deformation sensing * polymer composite Subject RIV: BK - Fluid Dynamics Impact factor: 1.852, year: 2013

  12. Freshwater bacteria are stoichiometrically flexible with a nutrient composition similar to seston

    Cotner, James B.; Hall, Edward K.; Scott, J. Thad; Heldal, Mikal

    2010-01-01

    Although aquatic bacteria are assumed to be nutrient-rich, they out-compete other foodweb osmotrophs for nitrogen (N) and phosphorus (P) an apparent contradiction to resource ratio theory. This paradox could be resolved if aquatic bacteria were demonstrated to be nutrient-poor relative other portions of the planktonic food web. In a survey of >120 lakes in the upper Midwest of the USA, the nutrient content of bacteria was lower than previously reported and very similar to the Redfield ratio, with a mean biomass composition of 102:12:1 (C:N:P). Individual freshwater bacterial isolates grown under P-limiting and P-replete conditions had even higher C:P and N:P ratios with a mean community biomass composition ratio of 875C:179N:1P suggesting that individual strains can be extremely nutrient-poor, especially with respect to P. Cell-specific measurements of individual cells from one lake confirmed that low P content could be observed at the community level in natural systems with a mean biomass composition of 259C:69N:1P. Variability in bacterial stoichiometry is typically not recognized in the literature as most studies assume constant and nutrient-rich bacterial biomass composition. We present evidence that bacteria can be extremely P-poor in individual systems and in culture, suggesting that bacteria in freshwater ecosystems can either play a role as regenerators or consumers of inorganic nutrients and that this role could switch depending on the relationship between bacterial biomass stoichiometry and resource stoichiometry. This ability to switch roles between nutrient retention and regeneration likely facilitates processing of terrestrial organic matter in lakes and rivers and has important implications for a wide range of bacterially mediated biogeochemical processes.

  13. 3D flexible NiTi-braided elastomer composites for smart structure applications

    Heller, Luděk; Vokoun, David; Šittner, Petr; Finckh, H.

    2012-01-01

    Roč. 21, č. 4 (2012), s. 1-13 ISSN 0964-1726 R&D Projects: GA ČR GAP108/10/1296 EU Projects: European Commission(XE) 46559 - CERINKA; European Commission(XE) 19945 - UPWIND; European Commission(XE) 515813 - AVALON Institutional research plan: CEZ:AV0Z10100520 Keywords : NiTi * braided structures * composites Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.024, year: 2012

  14. Biological Evaluation of Flexible Polyurethane/Poly l-Lactic Acid Composite Scaffold as a Potential Filler for Bone Regeneration

    Yuk Fai Lui

    2017-09-01

    Full Text Available Degradable bone graft substitute for large-volume bone defects is a continuously developing field in orthopedics. With the advance in biomaterial in past decades, a wide range of new materials has been investigated for their potential in this application. When compared to common biopolymers within the field such as PLA or PCL, elastomers such as polyurethane offer some unique advantages in terms of flexibility. In cases of bone defect treatments, a flexible soft filler can help to establish an intimate contact with surrounding bones to provide a stable bone-material interface for cell proliferation and ingrowth of tissue. In this study, a porous filler based on segmented polyurethane incorporated with poly l-lactic acid was synthesized by a phase inverse salt leaching method. The filler was put through in vitro and in vivo tests to evaluate its potential in acting as a bone graft substitute for critical-sized bone defects. In vitro results indicated there was a major improvement in biological response, including cell attachment, proliferation and alkaline phosphatase expression for osteoblast-like cells when seeded on the composite material compared to unmodified polyurethane. In vivo evaluation on a critical-sized defect model of New Zealand White (NZW rabbit indicated there was bone ingrowth along the defect area with the introduction of the new filler. A tight interface formed between bone and filler, with osteogenic cells proliferating on the surface. The result suggested polyurethane/poly l-lactic acid composite is a material with the potential to act as a bone graft substitute for orthopedics application.

  15. Electroactive nanoparticle directed assembly of functionalized graphene nanosheets into hierarchical structures with hybrid compositions for flexible supercapacitors

    Choi, Bong Gill; Huh, Yun Suk; Hong, Won Hi; Erickson, David; Park, Ho Seok

    2013-04-01

    Hierarchical structures of hybrid materials with the controlled compositions have been shown to offer a breakthrough for energy storage and conversion. Here, we report the integrative assembly of chemically modified graphene (CMG) building blocks into hierarchical complex structures with the hybrid composition for high performance flexible pseudocapacitors. The formation mechanism of hierarchical CMG/Nafion/RuO2 (CMGNR) microspheres, which is triggered by the cooperative interplay during the in situ synthesis of RuO2 nanoparticles (NPs), was extensively investigated. In particular, the hierarchical CMGNR microspheres consisting of the aggregates of CMG/Nafion (CMGN) nanosheets and RuO2 NPs provided large surface area and facile ion accessibility to storage sites, while the interconnected nanosheets offered continuous electron pathways and mechanical integrity. The synergistic effect of CMGNR hybrids on the supercapacitor (SC) performance was derived from the hybrid composition of pseudocapacitive RuO2 NPs with the conductive CMGNs as well as from structural features. Consequently, the CMGNR-SCs showed a specific capacitance as high as 160 F g-1, three-fold higher than that of conventional graphene SCs, and a capacitance retention of >95% of the maximum value even after severe bending and 1000 charge-discharge tests due to the structural and compositional features.Hierarchical structures of hybrid materials with the controlled compositions have been shown to offer a breakthrough for energy storage and conversion. Here, we report the integrative assembly of chemically modified graphene (CMG) building blocks into hierarchical complex structures with the hybrid composition for high performance flexible pseudocapacitors. The formation mechanism of hierarchical CMG/Nafion/RuO2 (CMGNR) microspheres, which is triggered by the cooperative interplay during the in situ synthesis of RuO2 nanoparticles (NPs), was extensively investigated. In particular, the hierarchical CMGNR

  16. Photocatalytic degradation of trichloroethylene in aqueous phase using nano-ZNO/Laponite composites

    Joo, Jin Chul; Ahn, Chang Hyuk; Jang, Dae Gyu; Yoon, Young Han; Kim, Jong Kyu; Campos, Luiza; Ahn, Hosang

    2013-01-01

    Highlights: • Stable nano-ZnO/Laponite composites (NZLc) as an alternative to TiO 2 were produced. • Nanoscale ZnO complexed with NZLc was found to be an effective photocatalyst. • TCE removal efficiency of NZLc was greater than that of bare nanoscale ZnO. • Nanoscale ZnO-mediated photodegradation varied with experimental conditions. • Developed NZLc overcame drawbacks (e.g., filtration and recovery of photocatalysts). -- Abstract: The feasibility of nano-ZnO/Laponite composites (NZLc) as a valid alternative to TiO 2 to mineralize trichloroethylene (TCE) without difficulties for recovery of photocatalysts was evaluated. Based on the experimental observations, the removal of TCE using NZLc under UV irradiation was multiple reaction processes (i.e., sorption, photolysis, and photocatalysis). Sorption of TCE was thermodynamically favorable due to the hydrophobic partitioning into crosslinked poly vinyl alcohol, and the adsorption onto high-surface-area mineral surfaces of both ZnO and Laponite. The degradation efficiency of TCE can be significantly improved using NZLc under UV irradiation, indicating that ZnO-mediated heterogeneous photocatalytic degradation occurred. However, the degradation efficiency was found to vary with experimental conditions (e.g., initial concentration of TCE, loading amount of NZLc, the intensity of light and initial solution pH). Although the removal of TCE by NZLc was found to be a complex function of sorption, photolysis, and photocatalysis, the photocatalytic degradation of TCE on the surface of ZnO was critical. Consequently, developed NZLc can be applied as a valid alternative to suspended TiO 2 powder, and overcome drawbacks (e.g., filtration and recovery of photocatalysts) in degradation of TCE for various water resources

  17. Photocatalytic degradation of trichloroethylene in aqueous phase using nano-ZNO/Laponite composites

    Joo, Jin Chul; Ahn, Chang Hyuk; Jang, Dae Gyu; Yoon, Young Han [Korea Institute of Construction Technology, Water Resource and Environment Research Department (Korea, Republic of); Kim, Jong Kyu; Campos, Luiza [University College London, Department of Civil, Environmental, and Geomatic Engineering (United Kingdom); Ahn, Hosang, E-mail: hahn@kict.re.kr [Korea Institute of Construction Technology, Water Resource and Environment Research Department (Korea, Republic of)

    2013-12-15

    Highlights: • Stable nano-ZnO/Laponite composites (NZLc) as an alternative to TiO{sub 2} were produced. • Nanoscale ZnO complexed with NZLc was found to be an effective photocatalyst. • TCE removal efficiency of NZLc was greater than that of bare nanoscale ZnO. • Nanoscale ZnO-mediated photodegradation varied with experimental conditions. • Developed NZLc overcame drawbacks (e.g., filtration and recovery of photocatalysts). -- Abstract: The feasibility of nano-ZnO/Laponite composites (NZLc) as a valid alternative to TiO{sub 2} to mineralize trichloroethylene (TCE) without difficulties for recovery of photocatalysts was evaluated. Based on the experimental observations, the removal of TCE using NZLc under UV irradiation was multiple reaction processes (i.e., sorption, photolysis, and photocatalysis). Sorption of TCE was thermodynamically favorable due to the hydrophobic partitioning into crosslinked poly vinyl alcohol, and the adsorption onto high-surface-area mineral surfaces of both ZnO and Laponite. The degradation efficiency of TCE can be significantly improved using NZLc under UV irradiation, indicating that ZnO-mediated heterogeneous photocatalytic degradation occurred. However, the degradation efficiency was found to vary with experimental conditions (e.g., initial concentration of TCE, loading amount of NZLc, the intensity of light and initial solution pH). Although the removal of TCE by NZLc was found to be a complex function of sorption, photolysis, and photocatalysis, the photocatalytic degradation of TCE on the surface of ZnO was critical. Consequently, developed NZLc can be applied as a valid alternative to suspended TiO{sub 2} powder, and overcome drawbacks (e.g., filtration and recovery of photocatalysts) in degradation of TCE for various water resources.

  18. Graphene and poly(methyl methacrylate) composite laminates on flexible substrates for volatile organic compound detection

    Rattanabut, Chanoknan; Wongwiriyapan, Winadda; Muangrat, Worawut; Bunjongpru, Win; Phonyiem, Mayuree; Song, Young Jae

    2018-04-01

    In this paper, we present a gas sensor for volatile organic compound (VOC) detection based on graphene and poly(methyl methacrylate) (GR/PMMA) composite laminates fabricated using CVD-grown graphene. Graphene was transferred to a poly(ethylene terephthalate) (PET) substrate by PMMA-supported wet transfer process without PMMA removal in order to achieve the deposition of GR/PMMA composite laminates on PET. The GR/PMMA and graphene sensors show completely different sensitivities to VOC vapors. The GR/PMMA and graphene sensors showed the highest sensitivities to dichloromethane (DCM). The response of the GR/PMMA sensor to DCM was 3 times higher than that of the graphene sensor but the GR/PMMA sensor hardly responded to acetone, chloroform, or benzene. The sensing mechanism of the graphene sensor can be based on the dielectric constant of VOCs, the size of VOC molecule, and electron hopping effects on defect graphene, while that of the GR/PMMA sensor can be explained in terms of the polymer swelling owing to the Hansen solubility parameter.

  19. Carbon nanotube/metal-sulfide composite flexible electrodes for high-performance quantum dot-sensitized solar cells and supercapacitors.

    Muralee Gopi, Chandu V V; Ravi, Seenu; Rao, S Srinivasa; Eswar Reddy, Araveeti; Kim, Hee-Je

    2017-04-19

    Carbon nanotubes (CNT) and metal sulfides have attracted considerable attention owing to their outstanding properties and multiple application areas, such as electrochemical energy conversion and energy storage. Here we describes a cost-effective and facile solution approach to the preparation of metal sulfides (PbS, CuS, CoS, and NiS) grown directly on CNTs, such as CNT/PbS, CNT/CuS, CNT/CoS, and CNT/NiS flexible electrodes for quantum dot-sensitized solar cells (QDSSCs) and supercapacitors (SCs). X-ray photoelectron spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the CNT network was covered with high-purity metal sulfide compounds. QDSSCs equipped with the CNT/NiS counter electrode (CE) showed an impressive energy conversion efficiency (η) of 6.41% and remarkable stability. Interestingly, the assembled symmetric CNT/NiS-based polysulfide SC device exhibited a maximal energy density of 35.39 W h kg -1 and superior cycling durability with 98.39% retention after 1,000 cycles compared to the other CNT/metal-sulfides. The elevated performance of the composites was attributed mainly to the good conductivity, high surface area with mesoporous structures and stability of the CNTs and the high electrocatalytic activity of the metal sulfides. Overall, the designed composite CNT/metal-sulfide electrodes offer an important guideline for the development of next level energy conversion and energy storage devices.

  20. Single layered flexible photo-detector based on perylene/graphene composite through printed technology

    Ali, Shawkat; Bae, Jinho; Lee, Chong Hyun

    2015-07-01

    In this paper, a single layered passive photo sensor based on perylene/graphene composite is proposed, which is deposited in comb type silver electrodes separated as 50 μm spacing. To increase an electrical conductivity of the proposed sensor, perylene and graphene are blended. Photo sensing layer (120nm thick) and Silver electrodes (50 μm width, 350 nm thick) are deposited on poly(ethylene terephthalate) (PET) substrate through electro-hydrodynamic (EHD) system. The proposed photo sensor detects a terminal resistance inversely varied by an incident light in the range between 78 GΩ in dark and 25 GΩ at light intensity of 400lux. The device response is maximum at 465 nm ~ 535 nm wavelength range at blue light. The device exhibited bendability up to 4mm diameter for 1000 endurance cycles. The surface morphology analysis is carried out with FE-SEM and microscope.

  1. Fluoro-apatite surface composition in aqueous solution deduced from potentiometric, electrokinetic, and solubility measurements, and spectroscopic observations

    Chairat, C.; Oelkers, E.H.; Schott, J.; Lartigue, J.E.

    2007-01-01

    The surface chemistry of fluoro-apatite in aqueous solution was investigated using electrokinetic techniques, potentiometric titrations, solubility measurements, and attenuated total reflection infrared spectroscopy. All methods indicate the formation of Ca/F depleted, P enriched altered layer via exchange reactions between H + and Ca 2+ , and OH - and F - at the fluoro-apatite (FAP) surface. Observations suggest that this leached layer has a di-calcium phosphate (CaHPO 4 ) composition and that it controls the apparent solubility of FAP. Electrokinetic measurements yield an iso-electric point value of 1 ± 0.5 consistent with a negatively charged FAP surface at pH ≥ 1. In contrast, surface titrations give an apparent pH of point of zero charge of similar to 7.7, consistent with a positively charged surface at pH ≤ 7.7. These differences are shown to stem from proton consumption by both proton exchange and dissolution reactions at the FAP surface. After taking account for these effects, FAP surface charge is shown to be negative to at least pH 4 by surface titration analysis. (authors)

  2. Development and use of thin film composite based positively charged nanofiltration membranes in separation of aqueous streams and nuclear effluents

    Dey, T.K.; Bindal, R.C.; Prabhakar, S.; Tewari, P.K.

    2010-01-01

    A new, positively charged, thin film composite (TFC) type nanofiltration membrane has been developed and studied for its use in various aqueous stream separations. The membrane, containing fixed quaternary ammonium moieties, was developed by insitu interfacial polymerization of a functionalized amine (polyethyleneimine) and terephthaloyl chloride on a suitable base membrane. The nature of the charge on the membrane was established by ATR FT IR spectroscopy and was estimated by determination of its ion exchange capacity. The membrane was tested for its performance in single solute feed systems containing salts of various combinations of univalent and bivalent ions (NaCl, Na 2 SO 4 , CaCl 2 and MgSO 4 ) in test cell as well as in 2512 spiral modules. The membrane gave differential separation profile for these solutes with high rejection for CaCl 2 and low rejection for Na 2 SO 4 due to positive charge on the membrane and the type of charge constituting the salts. The membrane was also used for separation of simulated effluent solution containing uranyl nitrate in combination with ammonium nitrate which is a common effluent generated in nuclear industry. Here also the membrane gave differential separation profile for uranyl nitrate and ammonium nitrate in their mixture by concentrating the former salt and passing the later. This helped separation of these two solutes in the mixture into two different streams. (author)

  3. Using Central Composite Experimental Design to Optimize the Degradation of Tylosin from Aqueous Solution by Photo-Fenton Reaction

    Abd Elaziz Sarrai

    2016-05-01

    Full Text Available The feasibility of the application of the Photo-Fenton process in the treatment of aqueous solution contaminated by Tylosin antibiotic was evaluated. The Response Surface Methodology (RSM based on Central Composite Design (CCD was used to evaluate and optimize the effect of hydrogen peroxide, ferrous ion concentration and initial pH as independent variables on the total organic carbon (TOC removal as the response function. The interaction effects and optimal parameters were obtained by using MODDE software. The significance of the independent variables and their interactions was tested by means of analysis of variance (ANOVA with a 95% confidence level. Results show that the concentration of the ferrous ion and pH were the main parameters affecting TOC removal, while peroxide concentration had a slight effect on the reaction. The optimum operating conditions to achieve maximum TOC removal were determined. The model prediction for maximum TOC removal was compared to the experimental result at optimal operating conditions. A good agreement between the model prediction and experimental results confirms the soundness of the developed model.

  4. Control of a flexible beam actuated by macro-fiber composite patches: I. Modeling and feedforward trajectory control

    Schröck, Johannes; Meurer, Thomas; Kugi, Andreas

    2011-01-01

    This paper considers a systematic approach for motion planning and feedforward control design for a flexible cantilever actuated by piezoelectric macro-fiber composite (MFC) patches. For accurate feedforward tracking control, special attention has to be paid to the inherent nonlinear hysteresis and creep behavior of these actuators. In order to account for these effects an appropriate compensator is applied which allows us to perform the tracking controller design on the basis of a linear infinite-dimensional model. A detailed analysis of the nonlinear actuator behavior as well as the compensator design and the overall experimental validation is presented in the companion paper (Schröck et al 2011 Smart Mater. Struct. 20 015016). The governing equations of motion of the hysteresis and creep compensated cantilever are determined by means of the extended Hamilton's principle. This allows us to consider the influence of the bonded patch actuators on the mechanical properties of the underlying beam structure in a straightforward manner and results in a model with spatially varying system parameters. For the solution of the motion planning and feedforward control problem a flatness-based methodology is proposed. In a first step, the infinite-dimensional system of the MFC-actuated flexible cantilever is approximated by a finite-dimensional model, where all system variables, i.e. the states, input and output, can be parameterized in terms of a so-called flat output. In a second step, it is shown by numerical simulations that these parameterizations converge with increasing system order of the finite-dimensional model such that the feedforward control input can be directly calculated in order to realize prescribed output trajectories

  5. Design and Development of a Flexible Strain Sensor for Textile Structures Based on a Conductive Polymer Composite

    Claude Dufour

    2007-04-01

    Full Text Available The aim of this work is to develop a smart flexible sensor adapted to textile structures, able to measure their strain deformations. The sensors are “smart” because of their capacity to adapt to the specific mechanical properties of textile structures that are lightweight, highly flexible, stretchable, elastic, etc. Because of these properties, textile structures are continuously in movement and easily deformed, even under very low stresses. It is therefore important that the integration of a sensor does not modify their general behavior. The material used for the sensor is based on a thermoplastic elastomer (Evoprene/carbon black nanoparticle composite, and presents general mechanical properties strongly compatible with the textile substrate. Two preparation techniques are investigated: the conventional melt-mixing process, and the solvent process which is found to be more adapted for this particular application. The preparation procedure is fully described, namely the optimization of the process in terms of filler concentration in which the percolation theory aspects have to be considered. The sensor is then integrated on a thin, lightweight Nylon fabric, and the electromechanical characterization is performed to demonstrate the adaptability and the correct functioning of the sensor as a strain gauge on the fabric. A normalized relative resistance is defined in order to characterize the electrical response of the sensor. Finally, the influence of environmental factors, such as temperature and atmospheric humidity, on the sensor performance is investigated. The results show that the sensor’s electrical resistance is particularly affected by humidity. This behavior is discussed in terms of the sensitivity of the carbon black filler particles to the presence of water.

  6. Flexible poly(ethylene carbonate)/garnet composite solid electrolyte reinforced by poly(vinylidene fluoride-hexafluoropropylene) for lithium metal batteries

    He, Zijian; Chen, Long; Zhang, Bochen; Liu, Yongchang; Fan, Li-Zhen

    2018-07-01

    Solid-state electrolytes with high ionic conductivities, great flexibility, and easy processability are needed for high-performance solid-state rechargeable lithium batteries. In this work, we synthesize nanosized cubic Li6.25Al0.25La3Zr2O12 (LLZO) by solution combustion method and develop a flexible garnet-based composite solid electrolyte composed of LLZO, poly(ethylene carbonate) (PEC), poly(vinylidene fluoride-hexafluoropropylene) (P(VdF-HFP) and lithium bis(fluorosulfonyl)imide (LiFSI)). In the flexible composite solid electrolytes, LLZO nanoparticles, as ceramic matrix, have a positive effect on ionic conductivities and lithium ion transference number (tLi+). PEC, as a fast ion-conducting polymer, possesses high tLi+ inherently. P(VdF-HFP), as a binder, can strengthen mechanical properties. Consequently, the as-prepared composite solid electrolyte demonstrates high tLi+ (0.82) and superb thermal stability (remaining LLZO matrix after burning). All-solid-state LiFePO4|Li cells assembled with the flexible composite solid electrolyte deliver a high initial discharge specific capacity of 121.4 mAh g-1 and good cycling stability at 55 °C.

  7. CNT/PDMS composite flexible dry electrodes for long-term ECG monitoring.

    Jung, Ha-Chul; Moon, Jin-Hee; Baek, Dong-Hyun; Lee, Jae-Hee; Choi, Yoon-Young; Hong, Joung-Sook; Lee, Sang-Hoon

    2012-05-01

    We fabricated a carbon nanotube (CNT)/ polydimethylsiloxane (PDMS) composite-based dry ECG electrode that can be readily connected to conventional ECG devices, and showed its long-term wearable monitoring capability and robustness to motion and sweat. While the dispersion of CNTs in PDMS is challenging, we optimized the process to disperse untreated CNTs within PDMS by mechanical force only. The electrical and mechanical characteristics of the CNT/PDMS electrode were tested according to the concentration of CNTs and its thickness. The performances of ECG electrodes were evaluated by using 36 types of electrodes which were fabricated with different concentrations of CNTs, and with a differing diameter and thickness. The ECG signals were obtained by using electrodes of diverse sizes to observe the effects of motion and sweat, and the proposed electrode was shown to be robust to both factors. The CNT concentration and diameter of the electrodes were critical parameters in obtaining high-quality ECG signals. The electrode was shown to be biocompatible from the cytotoxicity test. A seven-day continuous wearability test showed that the quality of the ECG signal did not degrade over time, and skin reactions such as itching or erythema were not observed. This electrode could be used for the long-term measurement of other electrical biosignals for ubiquitous health monitoring including EMG, EEG, and ERG.

  8. Manufacture of nano graphite oxides derived from aqueous glucose solutions and in-situ synthesis of magnetite–graphite oxide composites

    Liu, Xiang, E-mail: liuxiang@ahut.edu.cn; Zhao, Tiantian; Liu, Pengpeng; Cui, Ping, E-mail: cokecp@sohu.com; Hu, Peng

    2015-03-01

    A “bottom up” approach of manufacturing graphite oxides (GOs) derived from aqueous glucose solutions by virtue of an environmentally-friendly process and the way of in-situ synthesizing magnetite–GOs composites are described in this work in detail. The dehydrations among glucose molecules under hydrothermal condition result in the initial carbon quantum dots and ultimate GOs. The structural information of the GOs is obtained by the infrared, ultraviolet–visible and X-ray photoelectron spectra. The magnetite–GOs composites were obtained by a one-pot method under the same hydrothermal conditions as the one of preparing GOs. The composites perform high activities in catalytic degradation of Rhodamine B in the presence of hydrogen peroxides without extra heating or pH adjusting. Both the GOs and the magnetite–GOs composites are also assured by measurements of transmission electron microscope and X-ray powder diffraction. - Highlights: • Graphite oxides are made from aqueous glucose solutions by hydrothermal reaction. • A way of in-situ synthesizing composites of magnetite–graphite oxides is depicted. • The composites perform high activities in catalytic degradation of Rhodamine B.

  9. Fabrication and application of flexible graphene silk composite film electrodes decorated with spiky Pt nanospheres

    Liang, Bo; Fang, Lu; Hu, Yichuan; Yang, Guang; Zhu, Qin; Ye, Xuesong

    2014-03-01

    A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m-1. During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □-1 with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H2O2 electrode with a sensitivity of 0.56 mA mM-1 cm-2, a linear range of 0-2.5 mM and an ultralow detection limit of 0.2 μM (S/N = 3). A glucose biosensor electrode was further fabricated by enzyme immobilization. The results show a sensitivity of 150.8 μA mM-1 cm-2 and a low detection limit of 1 μM (S/N = 3) for glucose detection. The strategy of coating graphene sheets on a silk fibre surface provides a new approach for developing electrically conductive biomaterials, tissue engineering scaffolds, bendable electrodes, and wearable biomedical devices.A free-standing graphene silk composite (G/S) film was fabricated via vacuum filtration of a mixed suspension of graphene oxide and silk fibres, followed by chemical reduction. Spiky structured Pt nanospheres were grown on the film substrate by cyclic voltammetry electrodeposition. The electrical and mechanical performance of a single graphene coated silk fibre was investigated. The conductivity of a single graphene coated silk fibre is 57.9 S m-1. During 1000 bending measurements, the conductivity was stable and showed negligible variation. The G/S film has a sheet resistivity of 90 Ω □-1 with a porous and hierarchical structure. The spiky Pt nanosphere decorated G/S film was directly used as a H2O2 electrode with a

  10. A novel highly flexible, simple, rapid and low-cost fabrication tool for paper-based microfluidic devices (μPADs) using technical drawing pens and in-house formulated aqueous inks.

    Nuchtavorn, Nantana; Macka, Mirek

    2016-05-05

    Paper-based microfluidic devices (μPADs) are capable of achieving rapid quantitative measurements of a variety of analytes inexpensively. μPADs rely on patterning hydrophilic-hydrophobic regions on a sheet of paper in order to create capillary channels within impermeable fluidic brakes on the paper. Here, we present a novel, highly flexible and low-cost fabrication method using a desktop digital craft plotter/cutter and technical drawing pens with tip size of 0.5 mm. The pens were used with either commercial black permanent ink for drawing fluidic brakes, or with specialty in-house formulated aqueous inks. With the permanent marker ink it was possible to create barriers on paper rapidly and in a variety of designs in a highly flexible manner. For instance, a design featuring eight reservoirs can be produced within 10 s for each μPAD with a consistent line width of brakes (%RSD drawing pens provides flexibility in the use of in-house formulated inks, short fabrication time, simplicity and low cost. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

  11. Lead Sorption from Aqueous Solutions by Pseudomonas putida (p168 and its Composites with Palygorskite and Sepiolite Clays

    Marzieh tavanaei

    2017-02-01

    Full Text Available Introduction: Heavy metals contamination due to natural and anthropogenic sources is a global environmental concern. Lead (Pb is one of the very toxic heavy metals. Industrial production processes and their emissions, mining operation, smelting, combustion sources and solid waste incinerators are the primary sources of lead. This heavy metal has aberrant effects on the environment and living organisms. Hence, proper treatment of lead from soil and industrial wastewaters is very important. In order to remove toxic heavy metals from contaminated water systems, conventional methods such as chemical precipitation, coagulation, ion exchange, solvent extraction and filtration, evaporation and membrane methods are being used. These conventional methods generally have high costs and technical problems. Therefore, biosorption processes, in which microorganisms are used as sorbents, have been considered as economical and environmentally friendly options for removal of heavy metals from aqueous solution. Clay minerals are another group of sorbents used in removal of heavy metals from polluted environments. Furthermore, bacterial cells can be attached on clay mineral surfaces and form bacteria-mineral composites. These composites adsorb heavy metals and convert them into forms with low mobility and bioavailability. Pseudomonas putida is a unique microorganism with a high tendency to sorb and/or degrade certain environmental pollutants. Palygorskite and sepiolite are the fibrous clay minerals of arid and semiarid regions; their structures consist of ribbons and channels. These fibrous minerals have various applications in industry and the environment because of its large surface area and high adsorption capacity. The present study was conducted in order to determine the ability of Pseudomonas putida (P168, and its composites with palygorskite and sepiolite in lead sorption. Materials and Methods: The bacterial strain used in the present study was Pseudomonas

  12. Underwater thrust and power generation using flexible piezoelectric composites: an experimental investigation toward self-powered swimmer-sensor platforms

    Erturk, Alper; Delporte, Ghislain

    2011-01-01

    Fiber-based flexible piezoelectric composites offer several advantages to use in energy harvesting and biomimetic locomotion. These advantages include ease of application, high power density, effective bending actuation, silent operation over a range of frequencies, and light weight. Piezoelectric materials exhibit the well-known direct and converse piezoelectric effects. The direct piezoelectric effect has received growing attention for low-power generation to use in wireless electronic applications while the converse piezoelectric effect constitutes an alternative to replace the conventional actuators used in biomimetic locomotion. In this paper, underwater thrust and electricity generation are investigated experimentally by focusing on biomimetic structures with macro-fiber composite piezoelectrics. Fish-like bimorph configurations with and without a passive caudal fin (tail) are fabricated and compared. The favorable effect of having a passive caudal fin on the frequency bandwidth is reported. The presence of a passive caudal fin is observed to bring the second bending mode close to the first one, yielding a wideband behavior in thrust generation. The same smart fish configuration is tested for underwater piezoelectric power generation in response to harmonic excitation from its head. Resonant piezohydroelastic actuation is reported to generate milli-newton level hydrodynamic thrust using milli-watt level actuation power input. The average actuation power requirement for generating a mean thrust of 19 mN at 6 Hz using a 10 g piezoelastic fish with a caudal fin is measured as 120 mW. This work also discusses the feasibility of thrust generation using the harvested energy toward enabling self-powered swimmer-sensor platforms with comparisons based on the capacity levels of structural thin-film battery layers as well as harvested solar and vibrational energy

  13. Control of a flexible beam actuated by macro-fiber composite patches: II. Hysteresis and creep compensation, experimental results

    Schröck, Johannes; Meurer, Thomas; Kugi, Andreas

    2011-01-01

    This paper considers a flexible cantilever beam, which is actuated by piezoelectric macro-fiber composite (MFC) patch actuators. For accurate positioning tasks, special attention has to be paid to the inherent nonlinear hysteresis and creep behavior of these actuators. A detailed analysis of the MFC-actuated cantilever verifies that these nonlinearities can be efficiently captured by an operator-based model using Prandtl–Ishlinskii's theory. Based on a Hammerstein-like model with the nonlinearities at the input connected in series with a linear infinite-dimensional beam model it follows that hysteresis and creep effects can be compensated by application of the inverse operator. Experimental results prove the feasibility of this approach. With this result, the tracking accuracy of the combination of the compensator with the flatness-based feedforward control design as proposed in the companion paper (Schröck et al 2011 Smart Mater. Struct. 20 015015) can be verified. Measurements demonstrate the applicability of this approach for the realization of highly dynamic trajectories for the beam's tip deflection

  14. Aqueous-Processed Inorganic Thin-Film Solar Cells Based on CdSe(x)Te(1-x) Nanocrystals: The Impact of Composition on Photovoltaic Performance.

    Zeng, Qingsen; Chen, Zhaolai; Zhao, Yue; Du, Xiaohang; Liu, Fangyuan; Jin, Gan; Dong, Fengxia; Zhang, Hao; Yang, Bai

    2015-10-21

    Aqueous processed nanocrystal (NC) solar cells are attractive due to their environmental friendliness and cost effectiveness. Controlling the bandgap of absorbing layers is critical for achieving high efficiency for single and multijunction solar cells. Herein, we tune the bandgap of CdTe through the incorporation of Se via aqueous process. The photovoltaic performance of aqueous CdSexTe1-x NCs is systematically investigated, and the impacts of charge generation, transport, and injection on device performance for different compositions are deeply discussed. We discover that the performance degrades with the increasing Se content from CdTe to CdSe. This is mainly ascribed to the lower conduction band (CB) of CdSexTe1-x with higher Se content, which reduces the driving force for electron injection into TiO2. Finally, the performance is improved by mixing CdSexTe1-x NCs with conjugated polymer poly(p-phenylenevinylene) (PPV), and power conversion efficiency (PCE) of 3.35% is achieved based on ternary NCs. This work may provide some information to further optimize the aqueous-processed NC and hybrid solar cells.

  15. Using graphene/styrene-isoprene-styrene copolymer composite thin film as a flexible microstrip antenna for the detection of heptane vapors

    Olejnik, Robert; Matyas, Jiri; Slobodian, Petr; Riha, Pavel

    2018-03-01

    Most portable devices, such as mobile phones or tablets, use antennas made of copper. This paper demonstrates the possible use of antenna constructed from electrically conductive polymer composite materials for use in those applications. The method of preparation and the properties of the graphene/styrene-isoprene-styrene copolymer as flexible microstrip antenna are described in this contribution. Graphene/styrene-isoprene-styrene copolymer toluene solution was prepared by means of ultrasound and the PET substrate was dip coated to reach a fine thin film. The main advantages of using PET as a substrate are low weight and flexibility. The final size of the flexible microstrip antenna was 10 × 25 mm with thickness of 0.48 mm (PET substrate 0.25 mm) with a weight of 0.110 g. The resulting antenna operates at a frequency of 1.8 GHz and gain ‑40.02 dB.

  16. Etching process optimization using NH{sub 4}Cl aqueous solution to texture ZnO:Al films for efficient light trapping in flexible thin film solar cells

    Fernandez, S., E-mail: susanamaria.fernandez@ciemat.es [CIEMAT, Departamento de Energias Renovables, Madrid (Spain); Abril, O. de [ISOM and Departamento de Fisica Aplicada, Escuela Tecnica Superior de Ingenieros de Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Naranjo, F.B. [Grupo de Ingenieria Fotonica, Universidad de Alcala, Departamento de Electronica, Alcala de Henares, Madrid (Spain); Gandia, J.J. [CIEMAT, Departamento de Energias Renovables, Madrid (Spain)

    2012-04-02

    0.5 {mu}m-thick aluminum-doped zinc oxide (ZnO:Al) films were deposited at 100 Degree-Sign C on polyethylene terephthalate substrates by Radio Frequency magnetron sputtering. The as-deposited films were compact and dense, showing grain sizes of 32.0 {+-} 6.4 nm and resistivities of (8.5 {+-} 0.7) Multiplication-Sign 10{sup -4} {Omega} cm. The average transmittance in the visible wavelength range of the structure ZnO:Al/PET was around 77%. The capability of a novel two-step chemical etching using diluted NH{sub 4}Cl aqueous solution to achieve efficient textured surfaces for light trapping was analyzed. The results indicated that both the aqueous solution and the etching method resulted appropriated to obtain etched surfaces with a surface roughness of 32 {+-} 5 nm, haze factors at 500 nm of 9% and light scattering at angles up to 50 Degree-Sign . To validate all these results, a commercially ITO coated PET substrate was used for comparison.

  17. Flexible Composites for Space

    National Aeronautics and Space Administration — Payload mass reduction and packaging efficiency in launch vehicles are essential for deep space exploration.  Inflatable softgoods have been identified as attractive...

  18. Selective adsorption of cationic dyes from aqueous solution by polyoxometalate-based metal–organic framework composite

    Liu, Xiaoxia; Gong, Wenpeng; Luo, Jing; Zou, Chentao; Yang, Yun; Yang, Shuijin, E-mail: yangshuijin@163.com

    2016-01-30

    Graphical abstract: Selective adsorption ability of H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 toward MO (a), Rhb (b) and the removal rate of Rhb, MO and MB (c). - Highlights: • Using metal–organic framework (MOF) composite as an adsorbent was investigated. • Selective adsorption ability of the composite towards cationic dyes was proposed. • The removal rate of MOF was raised greatly by the modification of polyoxometalate. • The adsorption kinetic and isotherm were used to describe the adsorption process. • The thermodynamic parameters of the composite were investigated in detail. - Abstract: A novel environmental friendly adsorbent H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 was synthesized by a simple one-step reaction under solvothermal conditions and characterized by XRD, FTIR, thermogravimetric analyses (TGA) and N{sub 2} adsorption–desorption isotherms. The removal rate of H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 was quite greater (85%) than that of MOF-5 (almost zero), showing that the adsorption performance of porous MOF-5 can be improved through the modification of H{sub 6}P{sub 2}W{sub 18}O{sub 62}. Further study revealed that H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 exhibited a fast adsorption rate and selective adsorption ability towards the cationic dyes in aqueous solution. The removal rate was up to 97% for cationic dyes methylene blue (MB) and 68% for rhodamine B(Rhb) within 10 min. However, anionicdye methyl orange(MO) can only reach to 10%. The influences including initial concentration, contact time, initial solution pH and temperature of MB adsorption onto H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 were investigated in detail. The kinetic study indicated that the adsorption of MB onto H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 followed the pseudo second-order model well. The isotherm obtained from experimental data fitted the Langmuir model, yielding maximum adsorption capacity of 51.81 mg/g. The thermodynamic parameters analysis

  19. A facile strategy to construct binder-free flexible carbonate composite anode at low temperature with high performances for lithium-ion batteries

    Shi, Shaojun; Zhang, Ming; Deng, Tingting; Wang, Ting; Yang, Gang

    2017-01-01

    Graphical abstract: The schematic illustration of the strategy for preparations and the mechanism for the stability of structure Display Omitted -- Highlights: •A facile strategy is applied to construct flexible carbonate composite anode. •Carbon nano-fiber matrix serves as fast charge channel and efficient buffer. •High specific capacity of 958 mAh g −1 at 100 mA g −1 is obtained. •After 200 cycles at 1 A g −1 , there is not obvious capacity decline. •The mechanism for stress release is further analyzed. -- Abstract: High temperature is usually necessary for carbon modification or electrospinning to obtain flexible anode with excellent conductivity and stability. However, due to the unstable instinct of carbonate, it’s hard to obtain carbonate when any of the synthesis process undergoes high temperature treatment. Thus, a facile strategy is applied to construct binder-free flexible carbonate composite anode at low temperature with high electrochemical performances. The carbon nano-fiber matrix is first synthesized through electrospinning followed by a facile solvothermal process to in-situ grow carbonate on carbon nano-fibers to form a well combinative flexible anode. The carbon nano-fiber matrix serves not only as a fast channel for charge transfer, but also as an efficient buffer to release the stress resulting from the hysteresis of lithiation for carbonate particles during repeated charge/discharge cycles. Owing to the synergistic effect of carbon nano-fiber and the carbonate, the flexible anode exhibits high specific capacity of 958 mAh g −1 . And after 200 cycles at 1 A g −1 , no obvious capacity decline. The reaction mechanism for stress release is also well analyzed to display the merit of our strategy. It is considered as one of the most promising way to get binder-free flexible carbonate anode with remarkable properties.

  20. In vitro study on the composition and antibacterial effects of aqueous and methanol extracts of on some of food-borne pathogens

    A. Barati

    2016-08-01

    Full Text Available Scrophularia khorassanica belongs to the Scrophulariaceae family that geographically grows wild only in Iran-Khorasan. There is insufficient information about its composition and antibacterial activity. Due to the application of S. khorassanica and related species in traditional medicine, the aim of this study was to determine antimicrobial effect of S. khorassanica aqueous and methanolic extracts on the growth of Escherichia coli and Staphylococcus aureus and also to determine the composition of the essential oil in-vitro. Extracts and the essential oil were prepared respectively by maceration and hydro-distillation methods. The composition of the essential oil examined by GC/MS and the minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC determined by broth micro-dilution assay. Composition analysis identified a total of 28 various components in which the main components were 1,3-Bis (trimethylsilyl, benzene (34.93%, р-Cymene (12.55%, Palmitic acid (6.79, Thymol (6.22%, Linalool (4.59%, 2-undecanone(4.35%, Sorbitol(1.87%, Carvacrol (1.74%, γ-Terpinene (1.06%, β -Elemene (1.03% and α-Pinene (0.3%. The MIC for methanolic extract against E. coli and S. aureus was 12.5 and 25 mg/ml, respectively. In the case of aqueous extract, it was estimated at 6.25 and 12.5 mg/ml, respectively. Based on these results, the aqueous extract had the strongest antibacterial effect. It was concluded that Scrophularia khorassanica extract can be used as an natural preservative.

  1. Generation of native polythiophene/PCBM composite nanoparticles via the combination of ultrasonic micronization of droplets and thermocleaving from aqueous dispersion

    Nan, Yaxiong; Hu, Xiaolian; Larsen-Olsen, Thue Trofod

    2011-01-01

    -PT/PCBM nanoparticles were determined by atomic force microscopy (AFM), small-angle x-ray scattering (SAXS) and grazing incidence SAXS (GISAXS), giving an average size of ~ 140 nm. The GISAXS results reveal that n-PT/PCBM nanoparticles pack in an ordered structure as opposed to the P3MHOCT/PCBM nanoparticles......We report the preparation of native polythiophene (n-PT)/[6, 6]-phenyl-C61-butyric acid methyl ester (PCBM) composite nanoparticles from a poly[3-(2-methylhex-2-yl)oxy-carbonyldithiophene] (P3MHOCT)/PCBM aqueous dispersion prepared from an ultrasonically generated emulsion. The subsequent steps....... The successful vapour-phase preparation of phase-separated n-PT/PCBM nanoparticles provides a new route to all-aqueous processing of conjugated materials relevant to efficient polymer solar cells with long operational stability. The use of ultrasound was involved in both liquid and gas phases demonstrating...

  2. Flexible Lamination-Fabricated Ultra-High Frequency Diodes Based on Self-Supporting Semiconducting Composite Film of Silicon Micro-Particles and Nano-Fibrillated Cellulose

    Sani, Negar; Wang, Xin; Granberg, Hjalmar; Andersson Ersman, Peter; Crispin, Xavier; Dyreklev, Peter; Engquist, Isak; Gustafsson, Göran; Berggren, Magnus

    2016-06-01

    Low cost and flexible devices such as wearable electronics, e-labels and distributed sensors will make the future “internet of things” viable. To power and communicate with such systems, high frequency rectifiers are crucial components. We present a simple method to manufacture flexible diodes, operating at GHz frequencies, based on self-adhesive composite films of silicon micro-particles (Si-μPs) and glycerol dispersed in nanofibrillated cellulose (NFC). NFC, Si-μPs and glycerol are mixed in a water suspension, forming a self-supporting nanocellulose-silicon composite film after drying. This film is cut and laminated between a flexible pre-patterned Al bottom electrode and a conductive Ni-coated carbon tape top contact. A Schottky junction is established between the Al electrode and the Si-μPs. The resulting flexible diodes show current levels on the order of mA for an area of 2 mm2, a current rectification ratio up to 4 × 103 between 1 and 2 V bias and a cut-off frequency of 1.8 GHz. Energy harvesting experiments have been demonstrated using resistors as the load at 900 MHz and 1.8 GHz. The diode stack can be delaminated away from the Al electrode and then later on be transferred and reconfigured to another substrate. This provides us with reconfigurable GHz-operating diode circuits.

  3. Facile synthesis of amorphous FeOOH/MnO2 composites as screen-printed electrode materials for all-printed solid-state flexible supercapacitors

    Lu, Qiang; Liu, Li; Yang, Shuanglei; Liu, Jun; Tian, Qingyong; Yao, Weijing; Xue, Qingwen; Li, Mengxiao; Wu, Wei

    2017-09-01

    More convenience and intelligence life lead by flexible/wearable electronics requires innovation and hommization of power sources. Here, amorphous FeOOH/MnO2 composite as screen-printed electrode materials for supercapacitors (SCs) is synthesized by a facile method, and solid-state flexible SCs with aesthetic design are fabricated by fully screen-printed process on different substrates, including PET, paper and textile. The amorphous FeOOH/MnO2 composite shows a high specific capacitance and a good rate capability (350.2 F g-1 at a current density of 0.5 A g-1 and 159.5 F g-1 at 20 A g-1). It also possesses 95.6% capacitance retention even after 10 000 cycles. Moreover, the all-printed solid-state flexible SC device exhibits a high area specific capacitance of 5.7 mF cm-2 and 80% capacitance retention even after 2000 cycles. It also shows high mechanical flexibility. Simultaneously, these printed SCs on different substrates in series are capable to light up a 1.9 V yellow light emitting diode (LED), even after bending and stretching.

  4. Organizational Flexibility for Hypercompetitive Markets : Empirical Evidence of the Composition and Context Specificity of Dynamic Capabilities and Organization Design Parameters

    N.P. van der Weerdt (Niels)

    2009-01-01

    textabstractThis research project, which builds on the conceptual work of Henk Volberda on the flexible firm, empirically investigates four aspects of organizational flexibility. Our analysis of data of over 1900 firms and over 3000 respondents shows (1) that several increasing levels of

  5. Reduced graphene oxide-wrapped MoO3 composites prepared by using metal-organic frameworks as precursor for all-solid-state flexible supercapacitors.

    Cao, Xiehong; Zheng, Bing; Shi, Wenhui; Yang, Jian; Fan, Zhanxi; Luo, Zhimin; Rui, Xianhong; Chen, Bo; Yan, Qingyu; Zhang, Hua

    2015-08-26

    Reduced graphene oxide-wrapped MoO3M (rGO/MoO3 ) is prepared by a novel and simple method that is developed by using a metal-organic framework as the precursor. After a two-step annealing process, the obtained rGO/MoO3 composite is used for a high-performance supercapacitor electrode. Moreover, an all-solid-state flexible supercapacitor is fabricated based on the rGO/MoO3 composite, which shows stable performance under different bending states. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. NaCl leached sustainable porous flexible Fe3O4 decorated RGO-polyaniline/PVDF composite for durable application against electromagnetic pollution

    R. Bera

    2017-05-01

    Full Text Available To avoid the interference of electromagnetic radiation from other devices, an electronic device needs to be fabricated with flexible and light weight electromagnetic interference (EMI shielding materials with high efficiency. According, highly flexible porous poly(vinylidene fluoride (PVDF/PFR (Fe3O4 decorated polyaniline/RGO composite composite was prepared through solution blending of PVDF with pre-synthesized PFR conductive composite that involves in-situ oxidative polymerization of aniline in the presence of reduced graphene oxide (RGO using FeCl3 as oxidant. The porous morphology of the composite was created by leaching out of mixed NaCl from the composite. Polyaniline and RGO were mutually decorated by chemically in-situ synthesized ferrosoferric oxide (Fe3O4 using the Fe source of FeCl3. A homogeneous dispersion of PFR in insulated PVDF matrix resulted in a highly electrical conductive composite (PVDF-PFR material through formation of three dimensional continuous conductive networks of polyaniline-RGO in the matrix phase. The composite shows an outstanding EMI shielding effectiveness (EMI SE property due to the porous structure and the presence of conductive network and ferromagnetic Fe3O4 nanoparticles. The PVDF-PFR composite (0.5 mm thickness depicts a great permittivity and permeability value and achieve high EMI SE value (≈–28.18 dB and conductivity value of ≈1.10·10–1 S·cm–1 at very low loading (5 wt% of RGO.

  7. Preferential solvation and solvation shell composition of free base and protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin in aqueous organic mixed solvents

    Farajtabar, Ali; Jaberi, Fatemeh; Gharib, Farrokh

    2011-12-01

    The solvatochromic properties of the free base and the protonated 5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) were studied in pure water, methanol, ethanol (protic solvents), dimethylsulfoxide, DMSO, (non-protic solvent), and their corresponding aqueous-organic binary mixed solvents. The correlation of the empirical solvent polarity scale ( ET) values of TPPS with composition of the solvents was analyzed by the solvent exchange model of Bosch and Roses to clarify the preferential solvation of the probe dyes in the binary mixed solvents. The solvation shell composition and the synergistic effects in preferential solvation of the solute dyes were investigated in terms of both solvent-solvent and solute-solvent interactions and also, the local mole fraction of each solvent composition was calculated in cybotactic region of the probe. The effective mole fraction variation may provide significant physico-chemical insights in the microscopic and molecular level of interactions between TPPS species and the solvent components and therefore, can be used to interpret the solvent effect on kinetics and thermodynamics of TPPS. The obtained results from the preferential solvation and solvent-solvent interactions have been successfully applied to explain the variation of equilibrium behavior of protonation of TPPS occurring in aqueous organic mixed solvents of methanol, ethanol and DMSO.

  8. Nitrogen doped carbon derived from polyimide/multiwall carbon nanotube composites for high performance flexible all-solid-state supercapacitors

    Kim, Dae Kyom; Kim, Nam Dong; Park, Seung-Keun; Seong, Kwang-dong; Hwang, Minsik; You, Nam-Ho; Piao, Yuanzhe

    2018-03-01

    Flexible all-solid-state supercapacitors are desirable as potential energy storage systems for wearable technologies. Herein, we synthesize aminophenyl multiwall carbon nanotube (AP-MWCNT) grafted polyimide precursor by in situ polymerization method as a nitrogen-doped carbon precursor. Flexible supercapacitor electrodes are fabricated via a coating of carbon precursor on carbon cloth surface and carbonization at high temperature directly. The as-obtained electrodes, which can be directly used without any binders or additives, can deliver a high specific capacitance of 333.4 F g-1 at 1 A g-1 (based on active material mass) and excellent cycle stability with 103% capacitance retention after 10,000 cycles in a three-electrode system. The flexible all-solid-state supercapacitor device exhibits a high volumetric capacitance of 3.88 F cm-3 at a current density of 0.02 mA cm-3. And also the device can deliver a maximum volumetric energy density of 0.50 mWh cm-3 and presents good cycling stability with 85.3% capacitance retention after 10,000 cycles. This device cell can not only show extraordinary mechanical flexibilities allowing folding, twisting, and rolling but also demonstrate remarkable stable electrochemical performances under their forms. This work provides a novel approach to obtain carbon textile-based flexible supercapacitors with high electrochemical performance and mechanical flexibility.

  9. A stretchable polymer-carbon nanotube composite electrode for flexible lithium-ion batteries: porosity engineering by controlled phase separation

    Lee, Hojun; Yoo, Jung-Keun; Jung, Yeon Sik [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of); Park, Jong-Hyun [Material R and D Department, LG Display Co., Ltd., Paju-si, Gyeonggi-do (Korea, Republic of); Kim, Jin Ho [Icheon Branch, Korea Institute of Ceramic Engineering and Technology, Icheon-si, Gyeonggi-do (Korea, Republic of); Kang, Kisuk [Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)

    2012-08-15

    Flexible energy-storage devices have attracted growing attention with the fast development of bendable electronic systems. However, it still remains a challenge to find reliable electrode materials with both high mechanical flexibility/toughness and excellent electron and lithium-ion conductivity. This paper reports the fabrication and characterization of highly porous, stretchable, and conductive polymer nanocomposites embedded with carbon nanotubes (CNTs) for application in flexible lithium-ion batteries. The systematic optimization of the porous morphology is performed by controllably inducing the phase separation of polymethylmethacrylate (PMMA) in polydimethylsiloxane (PDMS) and removing PMMA, in order to generate well-controlled pore networks. It is demonstrated that the porous CNT-embedded PDMS nanocomposites are capable of good electrochemical performance with mechanical flexibility, suggesting these nanocomposites could be outstanding anode candidates for use in flexible lithium-ion batteries. The optimization of the pore size and the volume fraction provides higher capacity by nearly seven-fold compared to a nonporous nanocomposite. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Novel composite membrane coated with a poly(diallyldimethylammonium chloride)/urushi semi-interpenetrating polymer network for non-aqueous redox flow battery application

    Cho, Eunhae; Won, Jongok

    2016-12-01

    Novel composite membranes of a semi-interpenetrating network (semi-IPN) coated on the surfaces of a porous Celgard 2400 support are prepared and investigate for application in a non-aqueous redox flow battery (RFB). A natural polymer, urushi, is used for the matrix because of its high mechanical robustness, and poly(diallyldimethylammonium chloride) (PDDA) provides anionic exchange sites. The PDDA/urushi (P/U) semi-IPN film is prepared by the photo polymerization of urushiol in the presence of PDDA. The thin layer composed of the P/U semi-IPN on the porous support provides selectivity while maintaining the ion conductivity. The coulombic and energy efficiencies increase with increasing amounts of PDDA in the P/U semi-IPN layer, and the values reach 69.5% and 42.5%, respectively, for the one containing 40 wt% of PDDA. These values are substantially higher than those of the Neosepta AHA membrane and the Celgard membrane, indicating that the selective layer reduces the crossover of the redox active species through the membrane. This result implies that the formation of composite membranes using semi-IPN selective layers on the dimensionally stable porous membrane enable the successful use of a non-aqueous RFB for future energy storage systems.

  11. Room-temperature solution-processed and metal oxide-free nano-composite for the flexible transparent bottom electrode of perovskite solar cells

    Lu, Haifei; Sun, Jingsong; Zhang, Hong; Lu, Shunmian; Choy, Wallace C. H.

    2016-03-01

    The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self-assembly approach under ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting properties for a practical bottom electrode by controlling the degree of reduction of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on a polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self

  12. A Difference in Fatty Acid Composition of Isocaloric High-Fat Diets Alters Metabolic Flexibility in Male C57BL/6JOlaHsd Mice.

    Loes P M Duivenvoorde

    Full Text Available Poly-unsaturated fatty acids (PUFAs are considered to be healthier than saturated fatty acids (SFAs, but others postulate that especially the ratio of omega-6 to omega-3 PUFAs (n6/n3 ratio determines health. Health can be determined with biomarkers, but functional health status is likely better reflected by challenge tests that assess metabolic flexibility. The aim of this study was to determine the effect of high-fat diets with different fatty acid compositions, but similar n6/n3 ratio, on metabolic flexibility. Therefore, adult male mice received isocaloric high-fat diets with either predominantly PUFAs (HFpu diet or predominantly SFAs (HFs diet but similar n6/n3 ratio for six months, during and after which several biomarkers for health were measured. Metabolic flexibility was assessed by the response to an oral glucose tolerance test, a fasting and re-feeding test and an oxygen restriction test (OxR; normobaric hypoxia. The latter two are non-invasive, indirect calorimetry-based tests that measure the adaptive capacity of the body as a whole. We found that the HFs diet, compared to the HFpu diet, increased mean adipocyte size, liver damage, and ectopic lipid storage in liver and muscle; although, we did not find differences in body weight, total adiposity, adipose tissue health, serum adipokines, whole body energy balance, or circadian rhythm between HFs and HFpu mice. HFs mice were, furthermore, less flexible in their response to both fasting- re-feeding and OxR, while glucose tolerance was indistinguishable. To conclude, the HFs versus the HFpu diet increased ectopic fat storage, liver damage, and mean adipocyte size and reduced metabolic flexibility in male mice. This study underscores the physiological relevance of indirect calorimetry-based challenge tests.

  13. Design, simulation and characterization of a MEMS inertia switch with flexible CNTs/Cu composite array layer between electrodes for prolonging contact time

    Wang, Yang; Yang, Zhuoqing; Xu, Qiu; Chen, Wenguo; Ding, Guifu; Zhao, Xiaolin

    2015-01-01

    This paper reports an inertia switch with a flexible carbon nanotubes/copper (CNTs/Cu) composite array layer between movable and fixed electrodes, which achieves a longer contact time compared to the traditional design using rigid-to-rigid impact between electrodes. The CNTs/Cu layer is fabricated using the composite electroplating method, and the whole device is completed by multi-layer metal electroplating based on the micro-electro-mechanical systems (MEMS) process. The dynamic responses of the designed inertia switch and the contact impact between a single CNT and a fixed electrode/another CNT have both been simulated by the ANSYS finite-element-method (FEM). It is shown that the contact time of the designed inertia switch is about 100 µs under the applied 80 g half-sine-shaped acceleration in the sensing direction. Finally, the fabricated MEMS inertia switch with the flexible CNTs/Cu composite array layer between electrodes has been evaluated by a dropping hammer system. The test contact time is about112 µs, which has a good agreement with the simulation and is much longer than that of the traditional design. (paper)

  14. Chemical synthesis of composite HML / PDMcT / PAni and its application as the trhiodan adsorbent in aqueous solutions

    Girotto, L.G.; Pacheco, I.; Freitas, L.L. de; Oliveira, R.S.; Amaral, F.A. do; Canobre, S.C.

    2016-01-01

    The mixed hydroxide lamellar [Co -Al- Cl] was synthesize by the co- precipitation method constant pH 8. The synthesis composite HML/PDMcT/PAni was carried out via chemical. The DRX composite HML/PDMcT/PAni showed that one amorphicity in the conductor polymer doesn't hid the diffraction peaks characteristic of HML. The MEV micrographs of composite HDL / PDMcT / PAni showed a large number of crystallites compacts with several shapes characteristic to PDMcT and nanofibers of polyaniline indicating an association between the different constituents forming the composite. The results of the adsorption was 98% of the pesticide in the composite HML / PDMcT / PAni , the composite can contribute so significantly to one Thiodon withdrawal in contaminated pesticide waters. (author)

  15. Compositional changes in swine manure fibers treated with aqueous ammonia soaking (AAS) resulting in increased methane potential

    Jurado, Esperanza; Hansen, Mads A.T.; Gavala, Hariklia N.; Skiadas, Ioannis

    2013-01-01

    AAS treatment is a very efficient method to increase the methane potential of manure fibers. The chemical composition and supramolecular structures of swine manure fibers before and after AAS treatment was investigated in this study. Composition analyses, atomic force microscopy (AFM), scanning electron microscopy (SEM), and chemical surface composition by Attenuated Total Reflectance–Fourier Transform Infrared (ATR–FTIR) showed that no delignification of the lignocellulose took place during ...

  16. Effect of N,C-ITO on Composite N,C-Ti/N,C-ITO/ITO Electrode Used for Photoelectrochemical Degradation of Aqueous Pollutant with Simultaneous Hydrogen Production

    Kee-Rong Wu

    2012-01-01

    Full Text Available This study reports the effect of N,C-ITO (indium tin oxide layer on composite N,C-TiO2/N,C-ITO/ITO (Ti/TO electrode used for efficient photoelectrocatalytic (PEC degradation of aqueous pollutant with simultaneous hydrogen production. The structural properties of the composite Ti/TO electrode that determined by X-ray diffraction and Raman scattering, show primarily the crystallized anatase TiO2 phase and distinct diffraction patterns of polycrystalline In2O3 phase. Under solar light illumination, the composite Ti/TO electrode yields simultaneously a hydrogen production rate of 12.0 μmol cm−2 h−1 and degradation rate constant of  cm−2 h−1 in organic pollutant. It implies that the overlaid N,C-TiO2 layer enhances not only the photocurrent response of the composite Ti/TO electrode at entire applied potentials, but also the flat band potential; a shift of about 0.1 V toward cathode, which is desperately beneficial in the PEC process. In light of the X-ray photoelectron spectroscopy findings, these results are attributable partly to the synergetic effect of N,C-codoping into the TiO2 and ITO lattices on their band gap narrowing and photosensitizing as well. Thus, the Ti/TO electrode can potentially serve an efficient PEC electrode for simultaneous pollutant degradation and hydrogen production.

  17. Thin film composites in the BiFeO3–Bi4Ti3O12 system obtained by an aqueous solution-gel deposition methodology

    Carlos Gumiel

    2018-01-01

    Full Text Available Thin film multiferroic composites, with a high quantity of interfaces between the different materials, represent a more feasible alternative to single phase systems in which the multifunctional response is usually hampered due to intrinsic physical constraints. Nowadays some of these composites can be produced by applying deposition techniques such as PLD, CVD, MBE or the like, which allow a high degree of crystallographic control. However, despite their effectiveness, all these techniques also involve a high consumption of energy in terms of temperature and/or vacuum. Within this frame, the present contribution proposes a sustainable chemical solution deposition process to prepare thin films of the multiferroic BiFeO3–Bi4Ti3O12 composite system. More specifically an aqueous solution-gel plus spin-coating methodology is employed which also avoids the organic solvents typically used in a conventional sol–gel method, so further keeping an eye on the environmentally friendly conditions. Attempts are conducted that demonstrate how by systematically controlling the processing parameters it is possible to obtain thin film composites with a promising 3-3 type connectivity at temperatures as low as 600 °C.

  18. Thin film composites in the BiFeO3–Bi4Ti3O12 system obtained by an aqueous solution-gel deposition methodology

    Gumiel, C.; Vranken, T.; Bernardo, M.S.; Jardiel, T.; Hardy, A.; Van Bael, M.K.; Peiteado, M.

    2018-01-01

    Thin film multiferroic composites, with a high quantity of interfaces between the different materials, represent a more feasible alternative to single phase systems in which the multifunctional response is usually hampered due to intrinsic physical constraints. Nowadays some of these composites can be produced by applying deposition techniques such as PLD, CVD, MBE or the like, which allow a high degree of crystallographic control. However, despite their effectiveness, all these techniques also involve a high consumption of energy in terms of temperature and/or vacuum. Within this frame, the present contribution proposes a sustainable chemical solution deposition process to prepare thin films of the multiferroic BiFeO3–Bi4Ti3O12 composite system. More specifically an aqueous solution-gel plus spin-coating methodology is employed which also avoids the organic solvents typically used in a conventional sol–gel method, so further keeping an eye on the environmentally friendly conditions. Attempts are conducted that demonstrate how by systematically controlling the processing parameters it is possible to obtain thin film composites with a promising 3-3 type connectivity at temperatures as low as 600°C. [es

  19. Degradation of simazine from aqueous solutions by diatomite-supported nanosized zero-valent iron composite materials

    Sun, Zhiming [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Zheng, Shuilin [School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing 100083 (China); Ayoko, Godwin A.; Frost, Ray L. [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia); Xi, Yunfei, E-mail: y.xi@qut.edu.au [Chemistry Discipline, Faculty of Science and Technology, Queensland University of Technology, 2 George Street, GPO Box 2434, Brisbane, Queensland 4001 (Australia)

    2013-12-15

    Graphical abstract: Nanosized zero-valent iron (nZVI) particles were deposited onto acid-leached diatomite through centrifugation or rotary evaporation. The synthesis schematic diagram and morphology of the prepared nZVI/diatomite composites are shown in the illustration. The removal efficiency for herbicide simazine by nZVI/diatomite composites was compared with that of the pristine nZVI and the commercial iron powder. -- Highlights: • Diatomite-supported nanosized zero-valent iron composite was synthesised. • The obtained composites were characterised by XRD, SEM–EDS, TEM and XPS. • The removal efficiency for simazine in water were studied. • The prepared composite showed potential prospects in environmental remediation. -- Abstract: A novel composite material based on deposition of nanosized zero-valent iron (nZVI) particles on acid-leached diatomite was synthesised for the removal of a chlorinated contaminant in water. The nZVI/diatomite composites were characterised by X-ray diffraction, scanning electron microscopy, elemental analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. Compared with the pure nZVI particles, better dispersion of nZVI particles on the surface or inside the pores of diatom shells was observed. The herbicide simazine was selected as the model chlorinated contaminant and the removal efficiency by nZVI/diatomite composite was compared with that of the pristine nZVI and commercial iron powder. It was found that the diatomite supported nZVI composite material prepared by centrifugation exhibits relatively better efficient activity in decomposition of simazine than commercial Fe, lab synthesised nZVI and composite material prepared via rotary evaporation, and the optimum experimental conditions were obtained based on a series of batch experiments. This study on immobilising nZVI particles onto diatomite opens a new avenue for the practical application of nZVI and the diatomite-supported nanosized zero

  20. Selective removal of Cr(VI) from aqueous solution by polypyrrole/2,5-diaminobenzene sulfonic acid composite

    Kera, Nazia H

    2016-08-01

    Full Text Available and morphology of the composite were investigated by ATR-FTIR, FE-SEM, EDX, TGA, XRD and XPS studies. The adsorption of Cr(VI) by PPy/DABSA composite was highly pH dependent and optimum removal was achieved at pH 2. Adsorption of Cr(VI) was confirmed by EDX...

  1. Green preparation of a novel red mud@carbon composite and its application for adsorption of 2,4-dichlorophenoxyacetic acid from aqueous solution.

    Kazak, Omer; Eker, Yasin Ramazan; Akin, Ilker; Bingol, Haluk; Tor, Ali

    2017-10-01

    This study reports the eco-friendly preparation of a novel composite material consisting of red mud and carbon spheres, denoted as red mud@C composite, and its application for the removal of 2,4-dichlorophenoxyacetic acid herbicide (2,4-D) from aqueous solution. The preparation route has a green approach because it follows the low-energy consuming one-step hydrothermal process by using starch as a renewable carbon precursor and red mud as a waste from aluminum production industry. Characterization of the red mud@C composite was performed by FT-IR, TGA, SEM, TEM, BET, XRD, and Raman microscopy analyses. The batch adsorption studies revealed that the red mud@C composite has higher 2,4-D adsorption efficiency than those of the red mud and the naked carbon spheres. The maximum removal at initial pH of 3.0 is explained by considering the pKa of 2,4-D and pH of point of zero charge (pH pzc ) of the composite material. The adsorption equilibrium time was 60 min, which followed the pseudo-second-order kinetic model together with intra-particle diffusion model. The isotherm analysis indicated that Freundlich isotherm model better represented the adsorption data, with isotherm parameters of k [15.849 (mg/g) (mg/L) -1/n ] and n (2.985). The prepared composite is reusable at least 5 cycles of adsorption-desorption with no significant decrease in the adsorption capacity.

  2. Development of permanent magnet MnAlC/polymer composites and flexible filament for bonding and 3D-printing technologies

    Rial, Javier; de Vicente, Javier; Skårman, Björn; Vidarsson, Hilmar; Larsson, Per-Olof

    2018-01-01

    Abstract Searching for high-performance permanent magnets components with no limitation in shape and dimensions is highly desired to overcome the present design and manufacturing restrictions, which affect the efficiency of the final devices in energy, automotive and aerospace sectors. Advanced 3D-printing of composite materials and related technologies is an incipient route to achieve functional structures avoiding the limitations of traditional manufacturing. Gas-atomized MnAlC particles combined with polymer have been used in this work for fabricating scalable rare earth-free permanent magnet composites and extruded flexible filaments with continuous length exceeding 10 m. Solution casting has been used to synthesize homogeneous composites with tuned particles content, made of a polyethylene (PE) matrix embedding quasi-spherical particles of the ferromagnetic τ-MnAlC phase. A maximum filling factor of 86.5 and 72.3% has been obtained for the composite and the filament after extrusion, respectively. The magnetic measurements reveal no deterioration of the properties of the MnAlC particles after the composite synthesis and filament extrusion. The produced MnAlC/PE materials will serve as precursors for an efficient and scalable design and fabrication of end-products by different processing techniques (polymerized cold-compacted magnets and 3D-printing, respectively) in view of technological applications (from micro electromechanical systems to energy and transport applications).

  3. Core-shell N-doped active carbon fiber@graphene composites for aqueous symmetric supercapacitors with high-energy and high-power density

    Xie, Qinxing; Bao, Rongrong; Xie, Chao; Zheng, Anran; Wu, Shihua; Zhang, Yufeng; Zhang, Renwei; Zhao, Peng

    2016-06-01

    Graphene wrapped nitrogen-doped active carbon fibers (ACF@GR) of a core-shell structure were successfully prepared by a simple dip-coating method using natural silk as template. Compared to pure silk active carbon, the as-prepared ACF@GR composites exhibit high specific surface area in a range of 1628-2035 m2 g-1, as well as superior energy storage capability, an extremely high single-electrode capacitance of 552.8 F g-1 was achieved at a current density of 0.1 A g-1 in 6 M KOH aqueous electrolyte. The assembled aqueous symmetric supercapacitors are capable of deliver both high energy density and high power density, for instance, 17.1 Wh kg-1 at a power density of 50.0 W kg-1, and 12.2 Wh kg-1 at 4.7 kW kg-1 with a retention rate of 71.3% for ACF@GR1-based supercapacitor.

  4. Magnetic and photocatalytic response of Ag-doped ZnFeO nano-composites for photocatalytic degradation of reactive dyes in aqueous solution

    Mahmood, Asif; Ramay, Shahid Mahmood; Al-Zaghayer, Yousef S.; Imran, Muhammad; Atiq, Shahid; Al-Johani, Meshal S.

    2014-01-01

    Highlights: • Self-consistent sol–gel based auto-combustion route was used. • Photocatalytic degradation of reactive dyes in aqueous solution was investigated. • Due to Ag doping, band gap reduced. • Activity of Ag-doped samples was higher than that of un-doped ones. - Abstract: To investigate the photocatalytic degradation of reactive dyes in aqueous solution, pure ZnO and Fe/Ag-doped magnetic photocatalysts having nominal compositions of Zn 0.95−x Fe 0.05 Ag x O (x = 0.0, 0.05 and 0.1) have been synthesized via self-consistent sol–gel based auto-combustion route. Thermally stable samples were subsequently confirmed to exhibit wurtzite type hexagonal structure, characteristic of ZnO. The nature of chemical bonding was elaborated by Fourier transform analysis. Electron microscopic techniques were employed to investigate the structural morphology and to evaluate the particle size. Ferromagnetic nature of the Fe/Ag doped samples was revealed by vibrating sample magnetometry, enabling the photocatalytic samples to be re-collected magnetically for repeated usage. The enhanced photocatalytic activity in the degradation of methylene blue under UV light irradiation with 5 and 10 wt.% Ag/ZnFeO has been observed validating the potential applications of these materials in the field of photo-degradation of organic pollutants

  5. Influence of the composition of aqueous-alcohol solvents on the thermodynamic characteristics of L-phenylalanine dissolution at 298.15 K

    Badelin, Valentin G.; Smirnov, Valeriy I.

    2011-01-01

    Highlights: ► Enthalpies of L-phenylalanine dissolution have been measured in aqueous methanol, ethanol, 1-propanol and 2-propanol. ► The measured data were reported as functions of composition of water + alcohol mixtures. ► Enthalpy coefficients of pair-wise interactions have been analyzed in terms of McMillan-Mayer theory. ► A comparative analysis of the characteristics of dissolution of L-phenylalanine and some other L-amino acids in the similar systems has been made. - Abstract: The enthalpies of L-phenylalanine dissolution in aqueous methanol, ethanol, 1-propanol and 2-propanol have been determined by calorimetry at 298.15 K and alcohol mole fractions up to x 2 ∼0.4. The standard enthalpies of solution Δ sol H° and transfer Δ tr H° from water to the mixed solvent as well as the enthalpy coefficients of L-phenylalanine–alcohol pair-wise interactions were calculated. The interrelation of the enthalpies of dissolution and transfer for L-phenylalanine with structural features of alcohols has been determined. A comparative analysis of the thermodynamic characteristics of dissolution of L-phenylalanine and some other amino acids (glycine, L-alanine, L-threonine and L-valine) in the mixtures studied has been made.

  6. Graphene oxide reinforced poly (4-styrenesulfonic acid)/polyvinyl alcohol blend composites with enhanced dielectric properties for portable and flexible electronics

    Deshmukh, Kalim, E-mail: deshmukh.kalim@gmail.com [Department of Physics, B.S. Abdur Rahman University, Chennai, 600048, TN (India); Ahamed, M. Basheer [Department of Physics, B.S. Abdur Rahman University, Chennai, 600048, TN (India); Sadasivuni, Kishor Kumar [Mechanical and Industrial Engineering Department, Qatar University, P.O. Box 2713, Doha (Qatar); Ponnamma, Deepalekshmi; AlMaadeed, Mariam Al-Ali [Center for Advanced Materials, Qatar University, P.O. Box 2713, Doha (Qatar); Khadheer Pasha, S.K. [Department of Physics, School of Advanced Sciences, VIT University, Vellore, 632014, TN (India); Deshmukh, Rajendra R. [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai, 400019 (India); Chidambaram, K. [Department of Physics, School of Advanced Sciences, VIT University, Vellore, 632014, TN (India)

    2017-01-15

    In this work, Graphene Oxide (GO) reinforced novel polymer composites comprising of poly (4-styrenesulfonic acid) (PSSA) and polyvinyl alcohol (PVA) blend matrix have been developed using colloidal processing technique. The properties and the structure of prepared composites were investigated using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), UV–vis spectroscopy (UV), Thermogravimetric analysis (TGA), Polarized optical microscopy (POM), Scanning electron microscopy (SEM) and Atomic force microscopy (AFM). The FTIR and Raman spectroscopy analysis indicate the strong interfacial interaction between GO and PSSA/PVA blend matrix. The XRD and SEM analysis confirm that GO was fully exfoliated into individual graphene sheets and dispersed homogeneously within the polymer matrix. The effective reinforcement of GO into PSSA/PVA blend matrix has resulted in the enhancement of dielectric constant. The dielectric constant has increased from 82.67 (50 Hz, 150 °C) for PSSA/PVA (50/50) blend to 297.91 (50 Hz, 150 °C) for PSSA/PVA/GO composites with 3 wt % GO loading. The dielectric loss (tan δ) has increased from 1.56 (50 KHz, 140 °C) for PSSA/PVA (50/50) blend to 2.64 (50 KHz, 140 °C) for PSSA/PVA/GO composites with 3 wt % GO loading. These findings provide a new insight to fabricate flexible, high-k dielectric composite as a promising material for energy storage applications. - Highlights: • Graphene Oxide was prepared from natural graphite using modified Hummers method. • Novel PSSA/PVA/GO composites were prepared by reinforcing GO into PSSA/PVA blend matrix. • Molecular level dispersion of GO in PSSA/PVA blend matrix was successfully achieved. • Enhancement in the dielectric constant was observed due to effective reinforcement of GO in PSSA/PVA blend matrix. • PSSA/PVA/GO composites with high dielectric performances can be considered for energy storage applications.

  7. Genetic associations of body composition, flexibility and injury risk with ACE, ACTN3 and COL5A1 polymorphisms in Korean ballerinas

    Kim, Jun Ho; Jung, Eun Sun; Kim, Chul-Hyun; Youn, Hyeon; Kim, Hwa Rye

    2014-01-01

    [Purpose] The purpose of this study was to exam the association of body composition, flexibility, and injury risk to genetic polymorphisms including ACE ID, ACTN3 RX, and COL5A1 polymorphisms in ballet dancers in Korea. [Methods] For the purpose of this study, elite ballerinas (n = 97) and normal female adults (n = 203) aged 18 to 39 were recruited and these participants were tested for body weight, height, body fat, fat free mass, flexibility, injury risks on the joints and gene polymorphisms (ACE, ACTN3, COL5A1 polymorphism). [Results] As results, the ACE DD genotype in ballerinas was associated with higher body fat and percentage of body fat than the ACE II and ID genotypes (p sports injuries, the ankle injury of the XX-genotyped ballerinas was in significantly more prevalence than the RR and XX-genotyped ballerinas (p < 0.05). According to the odd ratio analysis, XX-genotyped ballerinas have the injury risk on the ankle about 4.7 (95% CI: 1.6~13.4, p < 0.05) times more than the RR and RX-genotyped ballerinas. Meanwhile, the COL5A1 polymorphism in ballerinas has no association with any factors including flexibility and injury risks. [Conclusion] In conclusion, ACE polymorphism and ACTN3 polymorphism were associated with ballerinas' performance capacity; COL5A1 was not associated with any factors of performance of Ballerinas. The results suggested that the ACE DD genotype is associated with high body fat, the ACTN3 XX genotype is associated with low fat-free mass, low flexibility, and higher risk of ankle-joint injury. PMID:25566457

  8. Comparative study on polyvinyl chloride film as flexible substrate for preparing free-standing polyaniline-based composite electrodes for supercapacitors.

    Wang, Hongxing; Liu, Dong; Du, Pengcheng; Wei, Wenli; Wang, Qi; Liu, Peng

    2017-11-15

    The free-standing polyaniline (PANI)-based composite film electrodes were prepared with polyvinyl chloride (PVC) and the aniline modified PVC (PVC-An) films as flexible substrates for supercapacitors, via facile in-situ chemical oxidative polymerization of aniline, with conventional chemical oxidative polymerization or rapid-mixing chemical oxidative polymerization technique. Owing to the grafting of PANI from the PVC-An film as substrate and the suppression of the secondary growth of the primary PANI particles in the rapid-mixing chemical oxidative polymerization, the PVC-g-PANI-2 composite film with loose surface possessed better comprehensive performance, accompanying the high specific capacitance (645.3F/g at a current density of 1A/g), good rate capacitance (retaining 63.2% of original value at a current density of 10A/g and 52.0% at a scan rate of 100mV/s), good cycle stability (retaining 83.1% after 1000 cycles) and the improved internal resistance. Besides its excellent flexibility, it could retain 61.2% of its original specific capacitance under the stress of 8.66MPa for 1h, demonstrating a good tensile-resistance. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Compositional changes in swine manure fibers treated with aqueous ammonia soaking (AAS) resulting in increased methane potential

    Jurado, Esperanza; Hansen, Mads A.T.; Gavala, Hariklia N.

    2013-01-01

    and accessible during subsequent anaerobic digestion. This finding has confirmed earlier experimental results, showing that delignification was not necessarily the limiting factor during conversion of manure fibers into methane while cellulose accessibility during digestion seemed more crucial.......AAS treatment is a very efficient method to increase the methane potential of manure fibers. The chemical composition and supramolecular structures of swine manure fibers before and after AAS treatment was investigated in this study. Composition analyses, atomic force microscopy (AFM), scanning...

  10. Lead-Free Sn-Ce-O Composite Coating on Cu Produced by Pulse Electrodeposition from an Aqueous Acidic Sulfate Electrolyte

    Sharma, Ashutosh; Das, Karabi; Das, Siddhartha

    2017-10-01

    Pulse-electrodeposited Sn-Ce-O composite solder coatings were synthesized on a Cu substrate from an aqueous acidic solution containing stannous sulfate (SnSO4·3H2O), sulfuric acid (H2SO4), and Triton X-100 as an additive. The codeposition was achieved by adding nano-cerium oxide powder in varying concentrations from 5 g/L to 20 g/L into the electrolytic bath. Microstructural characterization was carried out using x-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy. The XRD analysis showed that the deposits consist mainly of tetragonal β (Sn) with reduced cerium oxide species. The composite coatings thus obtained exhibit a smaller grain size, possess higher microhardness, and a lower melting point than the monolithic Sn coating. The electrical resistivity of the developed composites increases, however, but lies within the permissible limits for current lead-free solder applications. Also, an optimum balance of properties in terms of microhardness, adhesion, melting point and resistivity can be obtained with 0.9 wt.% cerium oxide in the Sn matrix, which enables potential applications in solder joints and packaging.

  11. Synthesis and Characterization of Self-Standing and Highly Flexible δ-MnO2@CNTs/CNTs Composite Films for Direct Use of Supercapacitor Electrodes.

    Wu, Peng; Cheng, Shuang; Yang, Lufeng; Lin, Zhiqiang; Gui, Xuchun; Ou, Xing; Zhou, Jun; Yao, Minghai; Wang, Mengkun; Zhu, Yuanyuan; Liu, Meilin

    2016-09-14

    Self-standing and flexible films worked as pseudocapacitor electrodes have been fabricated via a simple vacuum-filtration procedure to stack δ-MnO2@carbon nanotubes (CNTs) composite layer and pure CNT layer one by one with CNT layers ended. The lightweight CNTs layers served as both current collector and supporter, while the MnO2@CNTs composite layers with birnessite-type MnO2 worked as active layer and made the main contribution to the capacitance. At a low discharge current of 0.2 A g(-1), the layered films displayed a high areal capacitance of 0.293 F cm(-2) with a mass of 1.97 mg cm(-2) (specific capacitance of 149 F g(-1)) and thickness of only 16.5 μm, and hence an volumetric capacitance of about 177.5 F cm(-3). Moreover, the films also exhibited a good rate capability (only about 15% fading for the capacitance when the discharge current increased to 5 A g(-1) from 0.2 A g(-1)), outstanding cycling stability (about 90% of the initial capacitance was remained after 5,000 cycles) and high flexibility (almost no performance change when bended to different angles). In addition, the capacitance of the films increased proportionally with the stacked layers and the geometry area. E.g., when the stacked layers were three times many with a mass of 6.18 mg cm(-2), the areal capacitance of the films was increased to 0.764 F cm(-2) at 0.5 A g(-1), indicating a high electronic conductivity. It is not overstated to say that the flexible and lightweight layered films emerged high potential for future practical applications as supercapacitor electrodes.

  12. Degradation of simazine from aqueous solutions by diatomite-supported nanosized zero-valent iron composite materials.

    Sun, Zhiming; Zheng, Shuilin; Ayoko, Godwin A; Frost, Ray L; Xi, Yunfei

    2013-12-15

    A novel composite material based on deposition of nanosized zero-valent iron (nZVI) particles on acid-leached diatomite was synthesised for the removal of a chlorinated contaminant in water. The nZVI/diatomite composites were characterised by X-ray diffraction, scanning electron microscopy, elemental analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. Compared with the pure nZVI particles, better dispersion of nZVI particles on the surface or inside the pores of diatom shells was observed. The herbicide simazine was selected as the model chlorinated contaminant and the removal efficiency by nZVI/diatomite composite was compared with that of the pristine nZVI and commercial iron powder. It was found that the diatomite supported nZVI composite material prepared by centrifugation exhibits relatively better efficient activity in decomposition of simazine than commercial Fe, lab synthesised nZVI and composite material prepared via rotary evaporation, and the optimum experimental conditions were obtained based on a series of batch experiments. This study on immobilising nZVI particles onto diatomite opens a new avenue for the practical application of nZVI and the diatomite-supported nanosized zero-valent iron composite materials have potential applications in environmental remediation. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Adsorption of Amido Black 10B from aqueous solutions onto Zr (IV) surface-immobilized cross-linked chitosan/bentonite composite

    Zhang, Lujie; Hu, Pan; Wang, Jing; Huang, Ruihua

    2016-01-01

    Graphical abstract: - Highlights: • Zr-CCB was prepared and characterized. • The adsorption of AB10B followed the Langmuir isotherm model. • The pseudo-second-order model described the kinetic behavior. - Abstract: Zr(IV) surface-immobilized cross-linked chitosan/bentonite composite was synthesized by immersing cross-linked chitosan/bentonite composite in zirconium oxychloride solution, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy techniques. The adsorption of an anionic dye, Amido Black 10B, from aqueous solution by Zr(IV) loaded cross-linked chitosan/bentonite composite was investigated as a function of loading amount of Zr(IV), adsorbent dosage, pH value of initial dye solution, and ionic strength. The removal of Amido Black 10B increased with an increase in loading amount of Zr(IV) and adsorbent dosage, but decreased with an increase in pH or ionic strength. The adsorption of AB10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite was favored at lower pH values and higher temperatures. The Langmuir isotherm model fitted well with the equilibrium adsorption isotherm data and the maximum monolayer adsorption capacity was 418.4 mg/g at natural pH value and 298 K. The pseudo-second-order kinetic model well described the adsorption process of Amido Black 10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite. The possible mechanisms controlling Amido Black 10B adsorption included hydrogen bonding and electrostatic interactions.

  14. Adsorption of Amido Black 10B from aqueous solutions onto Zr (IV) surface-immobilized cross-linked chitosan/bentonite composite

    Zhang, Lujie; Hu, Pan; Wang, Jing; Huang, Ruihua, E-mail: hrh20022002@163.com

    2016-04-30

    Graphical abstract: - Highlights: • Zr-CCB was prepared and characterized. • The adsorption of AB10B followed the Langmuir isotherm model. • The pseudo-second-order model described the kinetic behavior. - Abstract: Zr(IV) surface-immobilized cross-linked chitosan/bentonite composite was synthesized by immersing cross-linked chitosan/bentonite composite in zirconium oxychloride solution, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy techniques. The adsorption of an anionic dye, Amido Black 10B, from aqueous solution by Zr(IV) loaded cross-linked chitosan/bentonite composite was investigated as a function of loading amount of Zr(IV), adsorbent dosage, pH value of initial dye solution, and ionic strength. The removal of Amido Black 10B increased with an increase in loading amount of Zr(IV) and adsorbent dosage, but decreased with an increase in pH or ionic strength. The adsorption of AB10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite was favored at lower pH values and higher temperatures. The Langmuir isotherm model fitted well with the equilibrium adsorption isotherm data and the maximum monolayer adsorption capacity was 418.4 mg/g at natural pH value and 298 K. The pseudo-second-order kinetic model well described the adsorption process of Amido Black 10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite. The possible mechanisms controlling Amido Black 10B adsorption included hydrogen bonding and electrostatic interactions.

  15. A comparison study of the nutritional, mineral and volatile compositions of three dry forms of ginger rhizomes, and antioxidant properties of their ethanolic and aqueous extracts

    Aicha Jelled

    2017-02-01

    Full Text Available Objective: To compare the most accessible dry forms of ginger rhizomes (Zingiber officinale used as a spice and as a remedy in order to choose the best ginger for medicinal purpose. Methods: Freshly air dried ginger, commercially dry rhizomes and ginger available in powder form are investigated in terms of nutritional values (proximate and mineral compositions and volatiles profile. Ethanolic and aqueous extracts (decoctions and infusions were prepared for total phenolic, flavonoid and tannin contents determination. Also, three standard tests were established in order to estimate the best extract with the better antioxidant potential. Results: The results showed unlike proximate composition revealing different nutritional values. In fact, freshly dried ginger contained much ash, while already dry samples contained much protein. In addition, mineral contents of studied samples indicated their dissimilar richness especially in Ca, Mg, Na, K, Cu, Fe, and Mn. Solid phase micro-extraction gave volatile profiles with many interesting compounds, only 26 from the 51 identified components were common to studied samples with bioactive compounds predominance in freshly dried sample. Also, the antioxidant potential established by three different tests was higher in already dry samples and was positively correlated with their higher contents in the determined phytochemicals. The ethanolic extracts showed higher antioxidant activities than aqueous extracts. Decoctions and infusions were almost similar proving that long cooking time did not affect ginger antioxidant potential. Conclusions: This work highlighted the benefits of traditional preparations of ginger as sources of bioactive compounds, namely antioxidants, and proved that the available commercial samples are not identical and encouraged analyzing samples before uses depending on needs.

  16. Aqueous cholesteric liquid crystals using uncharged rodlike polypeptides. Polypeptide vesicles by conformation-specific assembly. Ordered chiral macroporous hybrid silica-polypeptide composites

    Bellomo, Enrico Giuseppe

    2005-07-01

    Aqueous cholesteric liquid crystals using uncharged rodlike polypeptides . The aqueous, lyotropic liquid-crystalline phase behavior of an alpha helical polypeptide, has been studied using optical microscopy and X-ray scattering. Solutions of optically pure polypeptide were found to form cholesteric liquid crystals at volume fractions that decreased with increasing average chain length. At very high volume fractions, the formation of a hexagonal mesophase was observed. The pitch of the cholesteric phase could be varied by a mixture of enantiomeric samples, where the pitch increased as the mixture approached equimolar. The cholesteric phases could be untwisted, using either magnetic field or shear flow, into nematic phases, which relaxed into cholesterics upon removal of field or shear. We have found that the phase diagram of this polypeptide in aqueous solution parallels that of poly(gamma-benzyl glutamate) in organic solvents, thus providing a useful system for liquid-crystal applications requiring water as solvent. Polypeptide vesicles by conformation-specific assembly. We have found that block copolymers composed of polypeptide segments provide significant advantages in controlling both the function and supramolecular structure of bioinspired self-assemblies. Incorporation of the stable chain conformations found in proteins into block copolymers was found to provide an additional element of control, beyond amphiphilicity and composition that defines self-assembled architecture. The abundance of functionality present in amino acids, and the ease by which they can be incorporated into these materials, also provides a powerful mechanism to impart block copolypeptides with function. This combination of structure and function work synergistically to enable significant advantages in the preparation of therapeutic agents as well as provide insight into design of self-assemblies beginning to approach the complexity of natural structures such as virus capsids. Ordered

  17. Aqueous degradation kinetics of pharmaceutical drug diclofenac by photo catalysis using nano structured titania–zirconia composite catalyst

    Das, L.; Barodia, S. K.; Sengupta, S.; Basu, J. K.

    2015-01-01

    Diclofenac is an anti-inflammatory pharmaceutical drug and its presence in a trace amount in waste water makes severe environmental pollution. The degradation of diclofenac was investigated by a photo catalytic process in presence of ultra violet irradiation at room temperature using titania and titania-zirconia nano composite catalysts in a batch reactor. The composite catalyst was prepared by sol-gel method and characterized by X-ray diffraction, transmission electron microscopy as well as BET surface area analyzer. The effect of various process parameters such as catalyst loading, initial concentration of diclofenac and p H of the experimental solution was observed on the degradation of diclofenac. The titania-zirconia nano composites exhibited reasonably higher photo catalytic activity than that of anatase form of titania without zirconia. The maximum removal of diclofenac of about 92.41% was achieved using Zr/Ti mass ratio of 11.8 wt% composite catalyst. A rate equation was proposed for the degradation of diclofenac using the composite catalyst. The values of rate constant (kc) and adsorption equilibrium constant (K1) were found to vary with the catalyst content in the reaction mixture.

  18. Flexible Bronchoscopy.

    Miller, Russell J; Casal, Roberto F; Lazarus, Donald R; Ost, David E; Eapen, George A

    2018-03-01

    Flexible bronchoscopy has changed the course of pulmonary medicine. As technology advances, the role of the flexible bronchoscope for both diagnostic and therapeutic indications is continually expanding. This article reviews the historical development of the flexible bronchoscopy, fundamental uses of the flexible bronchoscope as a tool to examine the central airways and obtain diagnostic tissue, and the indications, complications, and contraindications to flexible bronchoscopy. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Mars Aqueous Processing System

    Berggren, Mark; Wilson, Cherie; Carrera, Stacy; Rose, Heather; Muscatello, Anthony; Kilgore, James; Zubrin, Robert

    2012-01-01

    The goal of the Mars Aqueous Processing System (MAPS) is to establish a flexible process that generates multiple products that are useful for human habitation. Selectively extracting useful components into an aqueous solution, and then sequentially recovering individual constituents, can obtain a suite of refined or semi-refined products. Similarities in the bulk composition (although not necessarily of the mineralogy) of Martian and Lunar soils potentially make MAPS widely applicable. Similar process steps can be conducted on both Mars and Lunar soils while tailoring the reaction extents and recoveries to the specifics of each location. The MAPS closed-loop process selectively extracts, and then recovers, constituents from soils using acids and bases. The emphasis on Mars involves the production of useful materials such as iron, silica, alumina, magnesia, and concrete with recovery of oxygen as a byproduct. On the Moon, similar chemistry is applied with emphasis on oxygen production. This innovation has been demonstrated to produce high-grade materials, such as metallic iron, aluminum oxide, magnesium oxide, and calcium oxide, from lunar and Martian soil simulants. Most of the target products exhibited purities of 80 to 90 percent or more, allowing direct use for many potential applications. Up to one-fourth of the feed soil mass was converted to metal, metal oxide, and oxygen products. The soil residue contained elevated silica content, allowing for potential additional refining and extraction for recovery of materials needed for photovoltaic, semiconductor, and glass applications. A high-grade iron oxide concentrate derived from lunar soil simulant was used to produce a metallic iron component using a novel, combined hydrogen reduction/metal sintering technique. The part was subsequently machined and found to be structurally sound. The behavior of the lunar-simulant-derived iron product was very similar to that produced using the same methods on a Michigan iron

  20. Biomimetic Hybridization of Kevlar into Silk Fibroin: Nanofibrous Strategy for Improved Mechanic Properties of Flexible Composites and Filtration Membranes.

    Lv, Lili; Han, Xiangsheng; Zong, Lu; Li, Mingjie; You, Jun; Wu, Xiaochen; Li, Chaoxu

    2017-08-22

    Silk, one of the strongest natural biopolymers, was hybridized with Kevlar, one of the strongest synthetic polymers, through a biomimetic nanofibrous strategy. Regenerated silk materials have outstanding properties in transparency, biocompatibility, biodegradability and sustainability, and promising applications as diverse as in pharmaceutics, electronics, photonic devices and membranes. To compete with super mechanic properties of their natural counterpart, regenerated silk materials have been hybridized with inorganic fillers such as graphene and carbon nanotubes, but frequently lose essential mechanic flexibility. Inspired by the nanofibrous strategy of natural biomaterials (e.g., silk fibers, hemp and byssal threads of mussels) for fantastic mechanic properties, Kevlar was integrated in regenerated silk materials by combining nanometric fibrillation with proper hydrothermal treatments. The resultant hybrid films showed an ultimate stress and Young's modulus two times as high as those of pure regenerated SF films. This is not only because of the reinforcing effect of Kevlar nanofibrils, but also because of the increasing content of silk β-sheets. When introducing Kevlar nanofibrils into the membranes of silk nanofibrils assembled by regenerated silk fibroin, the improved mechanic properties further enabled potential applications as pressure-driven nanofiltration membranes and flexible substrates of electronic devices.

  1. Free-standing and bendable carbon nanotubes/TiO2 nanofibres composite electrodes for flexible lithium ion batteries

    Zhang, Peng; Qiu, Jingxia; Zheng, Zhanfeng; Liu, Gao; Ling, Min; Martens, Wayde; Wang, Haihui; Zhao, Huijun; Zhang, Shanqing

    2013-01-01

    Carbon nanotube (CNT) and TiO 2 nanofibre composite films are prepared and used as anode materials for lithium ion batteries (LIBs) without the use of binders and conventional copper current collector. The preliminary experimental results from X-ray diffraction, scanning electron microscopy and transmission electron microscopy suggest that the TiO 2 nanofibres were well-dispersed and interwoven by the CNTs, forming freestanding, bendable and light weighted composite. In comparison with TiO 2 nanofibre based LIBs, the CNTs could significantly improve the battery performance due to their high conductivity property and 3D network morphology. In both 1–3 V and 0.01–3 V testing voltage ranges, the as-prepared composites show excellent reversible capacity and capacity retention. The superior lithium storage capacity of the CNT/TiO 2 composite was mainly attributed to dual functions of the CNTs – the CNTs not only provide conductive networks to assist the electron transfer but also facilitate lithium ion diffusion between the electrolyte and the TiO 2 active materials by preventing agglomeration of TiO 2 nanofibres. This work demonstrates that the CNT–TiO 2 composite film could be one type of potential electrode material for large-scale LIB applications

  2. The use of new, aqueous chemical wood modifications to improve the durability of wood-plastic composites

    Rebecca E. Ibach; Craig M. Clemons; George C. Chen

    2017-01-01

    The wood flour used in wood-plastic composites (WPCs) can biologically deteriorate and thus the overall mechanical performance of WPCs decrease when exposed to moisture and fungal decay. Protecting the wood flour by chemical modification can improve the durability of the wood in a nontoxic way so it is not harmful to the environment. WPCs were made with modified wood...

  3. Arsenic removal in aqueous solution by a novel Fe-Mn modified biochar composite: Characterization and mechanism.

    Lin, Lina; Qiu, Weiwen; Wang, Di; Huang, Qing; Song, Zhengguo; Chau, Henry Wai

    2017-10-01

    The aim of this study was to develop a cost-effective method for As removal from aqueous systems. To this end, pristine biochar (BC) was impregnated with Fe-Mn oxides and a comparative analysis was conducted on the adsorption capacities of BC, Fe-Mn binary oxide (FMO), and Fe/Mn modified biochar (FMBC). The ferromanganese oxides increased the specific surface areas of BC. FMBC presented greater adsorption of As (Q max = 8.25mgg -1 ) than FMO and BC. Energy dispersive spectrometer analysis and electron microscope scanning revealed numerous pores of FMBC with the existence of Fe-Mn oxide using. Distinguished binding energy shifting of the As3d, Fe2p, O1s, and Mn2p3/2 regions after As sorption were found, indicating that Mn(III) oxidation and interaction of oxygen-containing function groups in the FMBC promoted the conversion of As(III) to As(V). Furthermore, chemisorption was found to be the main mechanism for As sorption on FMBC. Thus, the results suggest that FMBC could be used as an inexpensive and highly efficient adsorbent for As removal from water environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Electrochemical Selective and Simultaneous Detection of Diclofenac and Ibuprofen in Aqueous Solution Using HKUST-1 Metal-Organic Framework-Carbon Nanofiber Composite Electrode

    Sorina Motoc

    2016-10-01

    Full Text Available In this study, the detection protocols for the individual, selective, and simultaneous determination of ibuprofen (IBP and diclofenac (DCF in aqueous solutions have been developed using HKUST-1 metal-organic framework-carbon nanofiber composite (HKUST-CNF electrode. The morphological and electrical characterization of modified composite electrode prepared by film casting was studied by scanning electronic microscopy and four-point-probe methods. The electrochemical characterization of the electrode by cyclic voltammetry (CV was considered the reference basis for the optimization of the operating conditions for chronoamperometry (CA and multiple-pulsed amperometry (MPA. This electrode exhibited the possibility to selectively detect IBP and DCF by simple switching the detection potential using CA. However, the MPA operated under optimum working conditions of four potential levels selected based on CV shape in relation to the potential value, pulse time, and potential level number, and order allowed the selective/simultaneous detection of IBP and DCF characterized by the enhanced detection performance. For this application, the HKUST-CNF electrode exhibited a good stability and reproducibility of the results was achieved.

  5. Electrochemical Selective and Simultaneous Detection of Diclofenac and Ibuprofen in Aqueous Solution Using HKUST-1 Metal-Organic Framework-Carbon Nanofiber Composite Electrode.

    Motoc, Sorina; Manea, Florica; Iacob, Adriana; Martinez-Joaristi, Alberto; Gascon, Jorge; Pop, Aniela; Schoonman, Joop

    2016-10-17

    In this study, the detection protocols for the individual, selective, and simultaneous determination of ibuprofen (IBP) and diclofenac (DCF) in aqueous solutions have been developed using HKUST-1 metal-organic framework-carbon nanofiber composite (HKUST-CNF) electrode. The morphological and electrical characterization of modified composite electrode prepared by film casting was studied by scanning electronic microscopy and four-point-probe methods. The electrochemical characterization of the electrode by cyclic voltammetry (CV) was considered the reference basis for the optimization of the operating conditions for chronoamperometry (CA) and multiple-pulsed amperometry (MPA). This electrode exhibited the possibility to selectively detect IBP and DCF by simple switching the detection potential using CA. However, the MPA operated under optimum working conditions of four potential levels selected based on CV shape in relation to the potential value, pulse time, and potential level number, and order allowed the selective/simultaneous detection of IBP and DCF characterized by the enhanced detection performance. For this application, the HKUST-CNF electrode exhibited a good stability and reproducibility of the results was achieved.

  6. Silver nanowire/polymer composite soft conductive film fabricated by large-area compatible coating for flexible pressure sensor array

    Chen, Sujie; Li, Siying; Peng, Sai; Huang, Yukun; Zhao, Jiaqing; Tang, Wei; Guo, Xiaojun

    2018-01-01

    Soft conductive films composed of a silver nanowire (AgNW) network, a neutral-pH PEDOT:PSS over-coating layer and a polydimethylsiloxane (PDMS) elastomer substrate are fabricated by large area compatible coating processes. The neutral-pH PEDOT:PSS layer is shown to be able to significantly improve the conductivity, stretchability and air stability of the conductive films. The soft conductive films are patterned using a simple maskless patterning approach to fabricate an 8 × 8 flexible pressure sensor array. It is shown that such soft conductive films can help to improve the sensitivity and reduce the signal crosstalk over the pressure sensor array. Project supported by the Science and Technology Commission of Shanghai Municipality (No. 16JC1400603).

  7. Possible mechanisms for the interaction of polymeric composite resins with Cu(II) ions in aqueous solution

    El-Zahhhar, A.A.; Abdel-Aziz, H.M.; Siyam, T.

    2005-01-01

    The interaction between the active groups of polymeric composite resins such as Poly(acrylamide-acrylic acid)-ethylenediaminetetra acetic acid disodium salt P(AM-AA)EDTANa 2 , Poly(acrylamide-acrylic acid)- montmorillonite P(AM-AA)-montmorillonite, and Poly(acrylamide-acrylic acid)-potassium nickel hexacyanoferrate P(AM-AA)-KNiHCF, with copper sulfate as a test ion has been studied. The spectroscopic studies show that the mechanism of interaction between polymeric composite resins and copper sulfate is a bond formation between the active groups of polymeric chains and copper ion. The bond formation depends on nature of polymeric chains. It was also found that the amide groups form complexes with hydrated cations, while carboxylate group interact by ion exchange mechanism through complex formation. Montmorillonite and hexacyanoferrate of the resins interact with metal ions by ion exchange mechanism

  8. Synthesis of molybdenum disulfide/reduced graphene oxide composites for effective removal of Pb(Ⅱ) from aqueous solutions

    Yi Du; Xiangke Wang; Jian wang; Yidong Zou; Wen Yao; Jing Hou; Liangshu Xia; Anguo Peng; Ahmed Alsaedi; Tasawar Hayat

    2017-01-01

    In this work,a facile method was adopted to synthesize molybdenum disulfide/reduced graphene oxide (MoS2/rGO) composites through an L-cysteine-assisted hydrothermal technique.The as-prepared MoS2/ rGO composites were firstly applied as adsorbents for efficient elimination of Pb(Ⅱ) ions.Batch adsorption experiments showed that the adsorption of Pb(Ⅱ) on MoS2/rGO followed pseudo-second-order kinetic model well.The adsorption of Pb(Ⅱ) was intensely pH-dependent,ionic strength-dependent at pH < 9.0 and ionic strength-independent at pH > 9.0.The presence of humic acid (HA) enhanced Pb(Ⅱ) adsorption obviously.The MoS2/rGO composites exhibited excellent adsorption capacity of 384.16 mg g-1 at pH 5.0 and T =298.15 K,which was superior to MoS2 (279.93 mg g-1) and many other adsorbents.The thermodynamic parameters suggested that the adsorption process of Pb(Ⅱ) on MoS2/rGO composites was spontaneous (△Gθ < 0) and endothermic (△Hθ > 0).The interaction of Pb(Ⅱ) and MoS2/ rGO was mainly dominated by electrostatic attraction and surface complexation between Pb(Ⅱ) and oxygen-containing functional groups of MoS2/rGO.This work highlighted the application of MoS2/rGO as novel and promising materials in the efficient elimination of Pb(Ⅱ) from contaminated water and industrial effluents in environmental pollution management.

  9. Preparation of modified polymer- Alumino silicate composite and their application in removal of some radionuclides from aqueous solutions

    El- Masry, E.H.

    2012-01-01

    Ion exchange is one of the most common and effective treatment methods for radioactive liquid waste. This technique is well developed and has been employed for many years in both the nuclear industry and in other industries. In this thesis polyacrylamide- zeolite and polyacrylamide- bentonite composites were prepared and characterized using advanced analytical techniques. The prepared materials were used as composite ion exchangers for removal of Cesium, Cobalt and Strontium ions from simulated waste solution. Effect of ph of the medium on the removal of aforementioned ions was investigated. The sorption kinetic was studied and the data were analyzed by different kinetic models which rivaled that the mechanism of the sorption processes is mainly controlled by pseudo-second order reaction, and particle diffusion might be involved in the sorption processes. The values of diffusion coefficient of the three metal ions were calculated and suggested that chemisorption was the predominated sorption mechanism. Several isotherm models were applied for the sorption, and thermodynamic parameters were determined. The positive values of enthalpy change, δH, for the three metal ions confirmed the endothermic nature of the sorption processes. The results indicated that the prepared materials can be used as efficient ion exchange materials for the removal of cesium, cobalt and strontium ions from simulated waste solution. In the present study, immobilization of polyacrylamide- zeolite and/ or polyacrylamide- bentonite composites loaded with cesium, cobalt and/or strontium radionuclides with Ordinary Portland Cement (OPC) has been carried out. Several factors affecting the characteristics of the final solidified waste product towards safe disposal such as mechanical strength and leaching behavior of the radioisotopes have been studied. The obtained results showed that the presence of polyacrylamide- zeolite and/ or polyacrylamide- bentonite composites in the cemented wastes

  10. Enhanced Photocatalytic Degradation and Mineralization of Furfural Using UVC/TiO2/GAC Composite in Aqueous Solution

    Bahram Ghasemi

    2016-01-01

    Full Text Available Titanium dioxide nanoparticles were immobilized on granular activated carbon (GAC as a porous and low-density support for photocatalytic degradation of furfural. The TiO2/GAC composite was synthetized using the simple sol-gel method and fully characterized. The effects of the operational parameters of furfural concentration (200–700 mg/L, initial pH (2–12, TiO2/GAC composite dosage (1–3.5 g/L, and irradiation time (20–120 min were studied. The synthetized TiO2/GAC composite exhibited a total pore volume of 0.13 cm3/g and specific surface area of 35.91 m2/g. Removal efficiency of up to 95% was observed at initial pH of 10, TiO2/GAC dosage of 2.5 g/L, irradiation time of 80 min, and initial furfural concentration of 500 mg/L. The photocatalyst could be reused at least four consecutive times with a mere 2% decrease in furfural removal efficiency. Mineralization efficiency of 94% was obtained within 80 min. Pseudo-first-order kinetics best fit the photocatalytic degradation of furfural under experimental conditions.

  11. Highly efficient removal of chlorotetracycline from aqueous solution using graphene oxide/TiO2 composite: Properties and mechanism

    Li, Zhaoqian; Qi, Mengyu; Tu, Chunyan; Wang, Weiping; Chen, Jianrong; Wang, Ai-Jun

    2017-12-01

    The extensive usage of chlorotetracycline (CTC) has caused the persistence of antibiotic residues in aquatic environments, resulting in serious threat to human health and ecosystems. In this study, graphene oxide/titanium dioxide (GO/TiO2) nanocomposite was successfully synthesized via in situ hydrolysis of tetra-n-butyl titanate (Ti(BuO)4) to TiO2 particles on GO sheets and used as adsorbent for efficient adsorptive removal of CTC from aqueous solution. The prepared GO/TiO2 was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transformed infrared (FT-IR), Raman spectroscopy and X-ray photoelectron (XPS). Adsorption kinetics, isotherms and thermodynamics were systematically investigated to evaluate the adsorption properties of GO/TiO2. Adsorption mechanism was further analyzed by FT-IR, UV-vis and XPS. The results indicated that adsorption kinetics closely followed the pseudo-second order model; the maximum adsorption capacity determined by Langmuir model was 261.10 mg g-1 at 298 K and the thermodynamic studies revealed that the adsorption of CTC onto the GO/TiO2 was a spontaneous and endothermic process. Moreover, the interactions between CTC and GO/TiO2 were presumed to be ligand exchange between CTC and TiO2, while the π-π electron donor-acceptor interaction, hydrogen bond and cation-π bonding were constructed between CTC and GO. Finally, the prepared GO/TiO2 was successfully applied for the efficient removal of CTC from Wu River water.

  12. Nickel-foam-supported ruthenium oxide/graphene sandwich composite constructed via one-step electrodeposition route for high-performance aqueous supercapacitors

    Li, Meng; He, Hanwei

    2018-05-01

    A high-performance supercapacitor both considered high power and high energy density is needed for its applications such as portable electronics and electric vehicles. Herein, we construct a high-performance ruthenium oxide/graphene (RuO2-ERG) composite directly grown on Ni foam through cyclic voltammetric deposition process. The RuO2-ERG composite with sandwich structure is achieved effectively from a mixed solution of graphene oxide and ruthenium trichloride in the -1.4 V to 1.0 V potential range at a scan rate of 5 mV s-1. The electrochemical performance is optimized by tuning the concentration of the ruthenium trichloride. This integrative RuO2-ERG composite electrode can effectively maintains the accessible surface for redox reaction and stable channels for electrolyte penetration, leading to an improved electrochemical performance. Symmetrical aqueous supercapacitors based on RuO2-ERG electrodes exhibit a wider operational voltage window of 1.5 V. The optimized RuO2-ERG electrode displays a superior specific capacitance with 89% capacitance retention upon increasing the current density by 50 times. A high energy density of 43.8 W h kg-1 at a power density of 0.75 kW kg-1 is also obtained, and as high as 39.1 W h kg-1 can be retained at a power density of 37.5 kW kg-1. In addition, the capacitance retention is still maintained at 92.8% even after 10,000 cycles. The excellent electrochemical performance, long-term cycle stability, and the ease of preparation demonstrate that this typical RuO2-ERG electrode has great potentialities to develop high-performance supercapacitors.

  13. Artificial Intelligence Based Optimization for the Se(IV) Removal from Aqueous Solution by Reduced Graphene Oxide-Supported Nanoscale Zero-Valent Iron Composites.

    Cao, Rensheng; Fan, Mingyi; Hu, Jiwei; Ruan, Wenqian; Wu, Xianliang; Wei, Xionghui

    2018-03-15

    Highly promising artificial intelligence tools, including neural network (ANN), genetic algorithm (GA) and particle swarm optimization (PSO), were applied in the present study to develop an approach for the evaluation of Se(IV) removal from aqueous solutions by reduced graphene oxide-supported nanoscale zero-valent iron (nZVI/rGO) composites. Both GA and PSO were used to optimize the parameters of ANN. The effect of operational parameters (i.e., initial pH, temperature, contact time and initial Se(IV) concentration) on the removal efficiency was examined using response surface methodology (RSM), which was also utilized to obtain a dataset for the ANN training. The ANN-GA model results (with a prediction error of 2.88%) showed a better agreement with the experimental data than the ANN-PSO model results (with a prediction error of 4.63%) and the RSM model results (with a prediction error of 5.56%), thus the ANN-GA model was an ideal choice for modeling and optimizing the Se(IV) removal by the nZVI/rGO composites due to its low prediction error. The analysis of the experimental data illustrates that the removal process of Se(IV) obeyed the Langmuir isotherm and the pseudo-second-order kinetic model. Furthermore, the Se 3d and 3p peaks found in XPS spectra for the nZVI/rGO composites after removing treatment illustrates that the removal of Se(IV) was mainly through the adsorption and reduction mechanisms.

  14. High-k dielectric composites of poly(2-cyanoethyl vinyl ether) and barium titanate for flexible electronics

    Piana, Francesco; Pfleger, Jiří; Jambor, R.; Řičica, T.; Macák, J. M.

    2017-01-01

    Roč. 134, č. 37 (2017), s. 1-10, č. článku 45236. ISSN 0021-8995 R&D Projects: GA TA ČR(CZ) TE01020022; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : composites * dielectric properties * nanocrystals Subject RIV: CG - Electrochemistry OBOR OECD: Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis) Impact factor: 1.860, year: 2016

  15. On flexibility

    Weiss, Christoph R.; Briglauer, Wolfgang

    2000-01-01

    By building on theoretical work by Mills and Schumann (1985) and Ungern-Sternberg (1990) this paper provides evidence on the determinants of two dimensions of flexibility, the flexibility in adjusting aggregate output over time (tactical flexibility) as well as the ability to switch quickly between products (operational flexibility). Econometric analysis of a sample of 40.000 farms in Upper-Austria for the period 1980 to 1990 suggests that larger full-time farms operated by younger, better ed...

  16. Effect of Target Composition and Sputtering Deposition Parameters on the Functional Properties of Nitrogenized Ag-Permalloy Flexible Thin Films Deposited on Polymer Substrates

    Waheed Khan

    2018-03-01

    Full Text Available We report the first results of functional properties of nitrogenized silver-permalloy thin films deposited on polyethylene terephthalic ester {PETE (C10H8O4n} flexible substrates by magnetron sputtering. These new soft magnetic thin films have magnetization that is comparable to pure Ni81Fe19 permalloy films. Two target compositions (Ni76Fe19Ag5 and Ni72Fe18Ag10 were used to study the effect of compositional variation and sputtering parameters, including nitrogen flow rate on the phase evolution and surface properties. Aggregate flow rate and total pressure of Ar+N2 mixture was 60 sccm and 0.55 Pa, respectively. The distance between target and the substrate was kept at 100 mm, while using sputtering power from 100–130 W. Average film deposition rate was confirmed at around 2.05 nm/min for argon atmosphere and was reduced to 1.8 nm/min in reactive nitrogen atmosphere. X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, vibrating sample magnetometer, and contact angle measurements were used to characterize the functional properties. Nano sized character of films was confirmed by XRD and SEM. It is found that the grain size was reduced by the formation of nitride phase, which in turns enhanced the magnetization and lowers the coercivity. Magnetic field coupling efficiency limit was determined from 1.6–2 GHz frequency limit. The results of comparable magnetic performance, lowest magnetic loss, and highest surface free energy, confirming that 15 sccm nitrogen flow rate at 115 W is optimal for producing Ag-doped permalloy flexible thin films having excellent magnetic field coupling efficiency.

  17. Flexible carbon nanofiber/polyvinylidene fluoride composite membranes as interlayers in high-performance Lithiumsbnd Sulfur batteries

    Wang, Zhenhua; Zhang, Jing; Yang, Yuxiang; Yue, Xinyang; Hao, Xiaoming; Sun, Wang; Rooney, David; Sun, Kening

    2016-10-01

    Traditionally polyvinylidene fluoride membranes have been used in applications such as membrane distillation, wastewater treatment, desalination and separator fabrication. Within this work we demonstrate that a novel carbon nanofiber/polyvinylidene fluoride (CNF/PVDF) composite membrane can be used as an interlayer for Lithiumsbnd Sulfur (Lisbnd S) batteries yielding both high capacity and long cycling life. This PVDF membrane is shown to effectively separate dissolved lithium polysulfide with the high electronic conductivity CNF not only reducing the internal resistance in the sulfur cathode but also helping immobilize the polysulfide through its abundant nanospaces. The resulting Lisbnd S battery assembled with the CNF/PVDF composite membrane effectively solves the polysulfide permeation problem and exhibits excellent electrochemical performance. It is further shown that the CNF/PVDF electrode has an excellent cycling stability and retains a capacity of 768.6 mAh g-1 with a coulombic efficiency above 99% over 200 cycles at 0.5C, which is more than twice that of a cell without CNF/PVDF (374 mAh g-1). In addition, the low-cost raw materials and the simple preparation process of CNF/PVDF composite membrane is also amenable for industrial production.

  18. PseKRAAC: a flexible web server for generating pseudo K-tuple reduced amino acids composition.

    Zuo, Yongchun; Li, Yuan; Chen, Yingli; Li, Guangpeng; Yan, Zhenhe; Yang, Lei

    2017-01-01

    The reduced amino acids perform powerful ability for both simplifying protein complexity and identifying functional conserved regions. However, dealing with different protein problems may need different kinds of cluster methods. Encouraged by the success of pseudo-amino acid composition algorithm, we developed a freely available web server, called PseKRAAC (the pseudo K-tuple reduced amino acids composition). By implementing reduced amino acid alphabets, the protein complexity can be significantly simplified, which leads to decrease chance of overfitting, lower computational handicap and reduce information redundancy. PseKRAAC delivers more capability for protein research by incorporating three crucial parameters that describes protein composition. Users can easily generate many different modes of PseKRAAC tailored to their needs by selecting various reduced amino acids alphabets and other characteristic parameters. It is anticipated that the PseKRAAC web server will become a very useful tool in computational proteomics and protein sequence analysis. Freely available on the web at http://bigdata.imu.edu.cn/psekraac CONTACTS: yczuo@imu.edu.cn or imu.hema@foxmail.com or yanglei_hmu@163.comSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  19. Non-monotonic piezoresistive behaviour of graphene nanoplatelet (GNP-polymer composite flexible films prepared by solvent casting

    S. Makireddi

    2017-07-01

    Full Text Available Graphene-polymer nanocomposite films show good piezoresistive behaviour and it is reported that the sensitivity increases either with the increased sheet resistance or decreased number density of the graphene fillers. A little is known about this behaviour near the percolation region. In this study, graphene nanoplatelet (GNP/poly (methyl methacrylate (PMMA flexible films are fabricated via solution casting process at varying weight percent of GNP. Electrical and piezoresistive behaviour of these films is studied as a function of GNP concentration. Piezoresistive strain sensitivity of the films is measured by affixing the film to an aluminium specimen which is subjected to monotonic uniaxial tensile load. The change in resistance of the film with strain is monitored using a four probe. An electrical percolation threshold at 3 weight percent of GNP is observed. We report non-monotonic piezoresistive behaviour of these films as a function GNP concentration. We observe an increase in gauge factor (GF with unstrained resistance of the films up to a critical resistance corresponding to percolation threshold. Beyond this limit the GF decreases with unstrained resistance.

  20. Aqueous geochemistry in icy world interiors: Equilibrium fluid, rock, and gas compositions, and fate of antifreezes and radionuclides

    Neveu, Marc; Desch, Steven J.; Castillo-Rogez, Julie C.

    2017-09-01

    serpentines, NH4-phyllosilicates, and carbonates on Ceres' surface; and of Na and NH4-carbonate and chloride in Ceres' bright spots. They also match results from previous modeling studies with similar assumptions, and systematically expand these results to heretofore unexplored physico-chemical conditions. This work involved the compilation and careful validation of a comprehensive PHREEQC database, which combines the advantages of the default databases phreeqc.dat (carefully vetted data, molar volumes) and llnl.dat (large diversity of species), and should be of broad use to anyone seeking to model aqueous geochemistry at pressures that differ from 1 bar with PHREEQC.

  1. How Solid-Electrolyte Interphase Forms in Aqueous Electrolytes.

    Suo, Liumin; Oh, Dahyun; Lin, Yuxiao; Zhuo, Zengqing; Borodin, Oleg; Gao, Tao; Wang, Fei; Kushima, Akihiro; Wang, Ziqiang; Kim, Ho-Cheol; Qi, Yue; Yang, Wanli; Pan, Feng; Li, Ju; Xu, Kang; Wang, Chunsheng

    2017-12-27

    Solid-electrolyte interphase (SEI) is the key component that enables all advanced electrochemical devices, the best representative of which is Li-ion battery (LIB). It kinetically stabilizes electrolytes at potentials far beyond their thermodynamic stability limits, so that cell reactions could proceed reversibly. Its ad hoc chemistry and formation mechanism has been a topic under intensive investigation since the first commercialization of LIB 25 years ago. Traditionally SEI can only be formed in nonaqueous electrolytes. However, recent efforts successfully transplanted this concept into aqueous media, leading to significant expansion in the electrochemical stability window of aqueous electrolytes from 1.23 V to beyond 4.0 V. This not only made it possible to construct a series of high voltage/energy density aqueous LIBs with unprecedented safety, but also brought high flexibility and even "open configurations" that have been hitherto unavailable for any LIB chemistries. While this new class of aqueous electrolytes has been successfully demonstrated to support diversified battery chemistries, the chemistry and formation mechanism of the key component, an aqueous SEI, has remained virtually unknown. In this work, combining various spectroscopic, electrochemical and computational techniques, we rigorously examined this new interphase, and comprehensively characterized its chemical composition, microstructure and stability in battery environment. A dynamic picture obtained reveals how a dense and protective interphase forms on anode surface under competitive decompositions of salt anion, dissolved ambient gases and water molecule. By establishing basic laws governing the successful formation of an aqueous SEI, the in-depth understanding presented in this work will assist the efforts in tailor-designing better interphases that enable more energetic chemistries operating farther away from equilibria in aqueous media.

  2. Earliest Results in the Use of Activated Composite Membranes for the Transport of Silver Ions from Aqueous Solutions

    Yucundo Mendoza-Tolentino

    2014-01-01

    Full Text Available This paper presents the results concerning the first use of activated composite membranes (ACMs for the facilitated transport of silver ions containing di-(2-ethylhexyl-dithiophosphoric acid (DTPA as the carrier. DTPA was immobilized by interfacial polymerization in a dense layer that was deposited in a porous layer, which was prepared on a nonwoven fabric support by phase inversion. The influence of fundamental parameters affecting the transport of silver ion as the carrier concentration in the membrane phase and stripping agent variation of the stripping solution have been studied. In the optimal conditions, the amount of silver transported across the ACMs was greater than 50%, whereas if the content of the carrier is modified, more than the 90% of the initial silver is removed from the feed phase.

  3. Efficient removal of uranium from aqueous solution by zero-valent iron nanoparticle and its graphene composite

    Li, Zi-Jie; Wang, Lin; Yuan, Li-Yong; Xiao, Cheng-Liang; Mei, Lei; Zheng, Li-Rong; Zhang, Jing; Yang, Ju-Hua; Zhao, Yu-Liang; Zhu, Zhen-Tai; Chai, Zhi-Fang; Shi, Wei-Qun

    2015-01-01

    Highlights: • Uranium removal by ZVI-nps: independent of pH, the presence of CO 3 2− , humic acid, or mimic groundwater constituents. • Rapid removal kinetics and sorption capacity of ZVI-nps is 8173 mg U/g. • Two reaction mechanisms: sufficient Fe 0 → reductive precipitation as U 3 O 7 ; insufficient Fe 0 → hydrolysis precipitation of U(VI). • Fe/graphene composites: improved kinetics and higher U(VI) reduction ratio. - Abstract: Zero-valent iron nanoparticle (ZVI-np) and its graphene composites were prepared and applied in the removal of uranium under anoxic conditions. It was found that solutions containing 24 ppm U(VI) could be completely cleaned up by ZVI-nps, regardless of the presence of NaHCO 3 , humic acid, mimic groundwater constituents or the change of solution pH from 5 to 9, manifesting the promising potential of this reactive material in permeable reactive barrier (PRB) to remediate uranium-contaminated groundwater. In the measurement of maximum sorption capacity, removal efficiency of uranium kept at 100% until C 0 (U) = 643 ppm, and the saturation sorption of 8173 mg U/g ZVI-nps was achieved at C 0 (U) = 714 ppm. In addition, reaction mechanisms were clarified based on the results of SEM, XRD, XANES, and chemical leaching in (NH 4 ) 2 CO 3 solution. Partially reductive precipitation of U(VI) as U 3 O 7 was prevalent when sufficient iron was available; nevertheless, hydrolysis precipitation of U(VI) on surface would be predominant as iron got insufficient, characterized by releases of Fe 2+ ions. The dissolution of Fe 0 cores was assigned to be the driving force of continuous formation of U(VI) (hydr)oxide. The incorporation of graphene supporting matrix was found to facilitate faster removal rate and higher U(VI) reduction ratio, thus benefitting the long-term immobilization of uranium in geochemical environment

  4. Extremely flexible, transparent, and strain-sensitive electroluminescent device based on ZnS:Cu-polyvinyl butyral composite and silver nanowires

    Jun, Sungwoo; Kim, Youngmin; Ju, Byeong-Kwon; Kim, Jong-Woong

    2018-01-01

    A multifunctional alternate current electroluminescent device (ACEL) was achieved by compositing ZnS:Cu particles in polyvinyl butyral (PVB) with two layers of percolated silver nanowire (AgNW) electrodes. The strong hydrogen bonding interactions and entanglement of PVB chains considerably strengthened the PVB, and thus, the cured mixture of ZnS:Cu particles and freestanding PVB required no additional support. The device was fabricated by embedding AgNWs on both sides of the ZnS:Cu-PVB composite film using an inverted layer process and intense-pulsed-light treatment. The strong affinity of PVB to the polyvinyl pyrrolidone (PVP) layer, which capped the AgNWs, mechanically stabilized the device to such an extent that it could resist 10,000 bending cycles under a curvature radius of 500 μm. Using AgNW networks in both the top and bottom electrodes made a double-sided light-emitting device that could be applied to wearable lightings or flexible digital signage. The capacitance formed in the device sensitively varied with the applied bending and unfolding, thus demonstrating that the device can also be used as a deformation sensor.

  5. High-Performance Flexible Solid-State Carbon Cloth Supercapacitors Based on Highly Processible N-Graphene Doped Polyacrylic Acid/Polyaniline Composites

    Wang, Yongguang; Tang, Shaochun; Vongehr, Sascha; Ali Syed, Junaid; Wang, Xiangyu; Meng, Xiangkang

    2016-01-01

    Improving the solubility of conductive polymers to facilitate processing usually decreases their conductivity, and they suffer from poor cycling stability due to swelling-shrinking during charging cycles. We circumvent these problems with a novel preparation method for nitrogen-doped graphene (NG) enhanced polyacrylic acid/polyaniline (NG-PAA/PANI) composites, ensuring excellent processibility for scalable production. The content of PANI is maximized under the constraint of still allowing defect-free coatings on filaments of carbon cloth (CC). The NG content is then adjusted to optimize specific capacitance. The optimal CC electrodes have 32 wt.% PANI and 1.3 wt.% NG, thus achieving a high capacitance of 521 F/g at 0.5 F/g. A symmetric supercapacitor made from 20 wt.% PANI CC electrodes has more than four times the capacitance (68 F/g at 1 A/g) of previously reported flexible capacitors based on PANI-carbon nanotube composites, and it retains the full capacitance under large bending angles. The capacitor exhibits high energy and power densities (5.8 Wh/kg at 1.1 kW/kg), a superior rate capability (still 81% of the 1 A/g capacitance at 10 A/g), and long-term electrochemical stability (83.2% retention after 2000 cycles). PMID:26883179

  6. Indium-free Cu/fluorine doped ZnO composite transparent conductive electrodes with stretchable and flexible performance on poly(ethylene terephthalate) substrate

    Han, Jun; Gong, Haibo; Yang, Xiaopeng; Qiu, Zhiwen; Zi, Min; Qiu, Xiaofeng; Wang, Hongqiang; Cao, Bingqiang

    2015-03-01

    Material-abundant ZnO and metal thin film have been proposed as potential alternatives for the most widely commercial indium tin oxide (ITO) transparent and conductive electrode. Yet the deterioration of optical transparency and conductivity for these materials makes them difficult to compete with ITO. In this work, a double-layer structured film-composed of FZO and Cu film is presented at room temperature, which combines the high transparency of FZO and high conductivity of Cu film. We first studied the effect of oxygen pressure on the transparency and conductivity of free-standing FZO layer deposited on poly(ethylene terephthalate) (PET) by PLD method. Also the structural, electrical, and optical properties of bilayers electrode dependence on the Cu layer thickness were optimized in detail. As the Cu layer thickness increases, the resistivity decreases. The lowest resistivity of 6.6 × 10-5 Ω cm with a carrier concentration of 1.11 × 1022 cm-3 and mobility of 8.52 cm2 V-1 s-1 was obtained at the optimum Cu (12 nm) layer thickness. We find that FZO layer have anti-reflection effect for Cu/FZO (250 nm) bilayer in the wavelength range of 650-1000 nm compared with single Cu layer. And we firstly study the stretchable performance for Cu film-based composite electrodes with stretching ratio changing from 0 to 5%. Furthermore, we study excellent mechanical flexibility and stability of composite electrodes by bending test.

  7. Facile method for the synthesis of a magnetic CNTs-C@Fe-chitosan composite and its application in tetracycline removal from aqueous solutions.

    Ma, Jie; Zhuang, Yuan; Yu, Fei

    2015-06-28

    A magnetic CNTs-C@Fe-chitosan composite (CNTs-C@Fe-CS) was prepared based on as-prepared carbon nanotubes (APCNTs). The metal nanoparticles in APCNTs could be utilized directly without any purification treatment, and the carbon shells provide an effective barrier against oxidation, acid dissolution, and movement of the MNPs, thus ensuring the long-term stability of CNTs-C@Fe-CS. The results showed that CNTs-C@Fe-CS contained more abundant oxygen and nitrogen containing functional groups after chitosan modification and the composite had good magnetization characteristics, even in acidic solutions. Then CNTs-C@Fe-CS was used as an adsorbent for the removal of tetracycline from aqueous solutions. Adsorption experiments indicated that CNTs-C@Fe-CS have a good adsorption capacity (qe) of tetracycline (104 mg g(-1)). The Freundlich isotherm model fitted the experimental data better than the Langmuir isotherm model. Kinetic regression results showed that the adsorption kinetics was more accurately represented by a pseudo second-order model. Intra-particle diffusion was involved in the adsorption, but it was not the only rate-controlling step. Cu(2+) and humic acid could promote the adsorption of tetracycline on CNTs-C@Fe-CS. The CNTs-C@Fe-CS adsorbents could be effectively and quickly separated by applying an external magnetic field and the adsorption capacity was still maintained at 99.3 mg g(-1) after being used 10 times. Therefore, CNTs-C@Fe-CS is a promising magnetic nanomaterial for preconcentration and separation of organic pollutants for environmental remediation.

  8. Phytochemical Composition, Antioxidant Activity, and the Effect of the Aqueous Extract of Coffee (Coffea arabica L.) Bean Residual Press Cake on the Skin Wound Healing.

    Affonso, Regina Celis Lopes; Voytena, Ana Paula Lorenzen; Fanan, Simone; Pitz, Heloísa; Coelho, Daniela Sousa; Horstmann, Ana Luiza; Pereira, Aline; Uarrota, Virgílio Gavicho; Hillmann, Maria Clara; Varela, Lucas Andre Calbusch; Ribeiro-do-Valle, Rosa Maria; Maraschin, Marcelo

    2016-01-01

    The world coffee consumption has been growing for its appreciated taste and its beneficial effects on health. The residual biomass of coffee, originated in the food industry after oil extraction from coffee beans, called coffee beans residual press cake, has attracted interest as a source of compounds with antioxidant activity. This study investigated the chemical composition of aqueous extracts of coffee beans residual press cake (AE), their antioxidant activity, and the effect of topical application on the skin wound healing, in animal model, of hydrogels containing the AE, chlorogenic acid (CGA), allantoin (positive control), and carbopol (negative control). The treatments' performance was compared by measuring the reduction of the wound area, with superior result ( p coffee AE (78.20%) with respect to roasted coffee AE (53.71%), allantoin (70.83%), and carbopol (23.56%). CGA hydrogels reduced significantly the wound area size on the inflammatory phase, which may be associated with the well known antioxidant and anti-inflammatory actions of that compound. The topic use of the coffee AE studied improved the skin wound healing and points to an interesting biotechnological application of the coffee bean residual press cake.

  9. Phytochemical Composition, Antioxidant Activity, and the Effect of the Aqueous Extract of Coffee (Coffea arabica L. Bean Residual Press Cake on the Skin Wound Healing

    Regina Celis Lopes Affonso

    2016-01-01

    Full Text Available The world coffee consumption has been growing for its appreciated taste and its beneficial effects on health. The residual biomass of coffee, originated in the food industry after oil extraction from coffee beans, called coffee beans residual press cake, has attracted interest as a source of compounds with antioxidant activity. This study investigated the chemical composition of aqueous extracts of coffee beans residual press cake (AE, their antioxidant activity, and the effect of topical application on the skin wound healing, in animal model, of hydrogels containing the AE, chlorogenic acid (CGA, allantoin (positive control, and carbopol (negative control. The treatments’ performance was compared by measuring the reduction of the wound area, with superior result (p<0.05 for the green coffee AE (78.20% with respect to roasted coffee AE (53.71%, allantoin (70.83%, and carbopol (23.56%. CGA hydrogels reduced significantly the wound area size on the inflammatory phase, which may be associated with the well known antioxidant and anti-inflammatory actions of that compound. The topic use of the coffee AE studied improved the skin wound healing and points to an interesting biotechnological application of the coffee bean residual press cake.

  10. Antioxidant Capacity and Polyphenolic Composition as Quality Indicators for Aqueous Infusions of Salvia officinalis L. (sage tea).

    Walch, Stephan G; Tinzoh, Laura Ngaba; Zimmermann, Benno F; Stühlinger, Wolf; Lachenmeier, Dirk W

    2011-01-01

    Sage (Salvia officinalis L.) is used as an herbal medicinal product, with the most typical form of application as infusion with boiling water (sage tea). The well-established traditional uses include symptomatic treatment of mild dyspeptic complaints, the treatment of inflammations in the mouth and the throat, and relief of excessive sweating and relief of minor skin inflammations. In this study, sage teas prepared from commercially available products were chemically analyzed for polyphenolic content using liquid chromatography, for antioxidant potential using the oxygen radical absorbance capacity method, and for the Folin-Ciocalteu (FC) index. The sage teas showed a high variation for all parameters studied (up to 20-fold differences for rosmarinic acid). Univariate and multivariate analyses showed that the antioxidant potential, which varied between 0.4 and 1.8 mmol trolox equivalents/100 mL, was highly dependent on rosmarinic acid and its derivatives. The FC index also showed a high correlation to these polyphenols, and could therefore be used as a screening parameter for sage tea quality. The considerable differences in polyphenolic composition and antioxidant capacity between the brands lead to a demand for quality standardization, especially if these sage teas are to be used for therapeutic purposes. Further research also appears to be necessary to characterize the dose-benefit relationship, as sage may also contain a constituent (thujone) with potentially adverse effects.

  11. Voltammetric studies on composition and stabilities of complexes of tetracycline and oxytetracycline with some metal ions in aqueous medium

    Ghandour, M.A.; Azab, H.A.; Hassan, A.; Ali, A.M.

    1992-01-01

    The composition and stability of complexes of tetracycline and oxytetracycline with Cu(II), Cd(II), Pb(II) and UO 2 (II) have been studied polarographically (direct current and differential pulse polarographic techniques) at 25±0.1 deg C. Differential pulse polarographic studies have been particularly helpful in deciding the nature of metal-drug interactions at low concentrations. The reduction of Cu(II)-tetracycline has been found to be irreversible and diffusion controlled with the presence of an adsorption component. In the system uranyl(II)-tetracycline the complex formed has a stoichiometry of 1:1 and log K ox = 4.04 which is very close to that obtained by potentiometric measurements. The peak half width W 1/2 of the Pb(II)-OTC system is 60-70 mV indicating that the process is reversible and two electrons are consumed. The log β' is 10.30 in 0.1 mol dm -3 NaClO 4 . In the Cu(II)-OTC system two complexes were formed with log β 1 ' = 8.50 and log β 2 ' = 14.10. Cyclic voltammograms were recorded using a hanging dropping mercury electrode for the systems Cu(II), Cd(II), Pb(II) and UO 2 (II)-OTC to examine the irregularities in both peak potentials and peak currents during the polarographic investigations. (authors)

  12. Antioxidant capacity and polyphenolic composition as quality indicators for aqueous infusions of Salvia officinalis L. (sage tea

    Stephan G Walch

    2011-12-01

    Full Text Available Sage (Salvia officinalis L. is used as an herbal medicinal product, with the most typical form of application as infusion with boiling water (sage tea. The well-established traditional uses include symptomatic treatment of mild dyspeptic complaints, the treatment of inflammations in the mouth and the throat, and relief of excessive sweating and relief of minor skin inflammations. In this study, sage teas prepared from commercially available products were chemically analysed for polyphenolic content using liquid chromatography, for antioxidant potential using the oxygen radical absorbance capacity (ORAC method, and for the Folin-Ciocalteu (FC index. The sage teas showed a high variation for all parameters studied (up to 20-fold differences for rosmarinic acid. Univariate and multivariate analyses showed that the antioxidant potential, which varied between 0.4 and 1.8 mmol trolox equivalents/100 mL, was highly dependent on rosmarinic acid and its derivatives. The FC index also showed a high correlation to these polyphenols, and could therefore be used as a screening parameter for sage tea quality. The considerable differences in polyphenolic composition and antioxidant capacity between the brands lead to a demand for quality standardisation, especially if these sage teas are to be used for therapeutic purposes. Further research also appears to be necessary to characterise the dose-benefit relationship, as sage may also contain a constituent (thujone with potentially adverse effects.

  13. Flexible, Heat-Resistant, and Flame-Retardant Glass Fiber Nonwoven/Glass Platelet Composite Separator for Lithium-Ion Batteries

    Ulrich Schadeck

    2018-04-01

    Full Text Available A new type of high-temperature stable and self-supporting composite separator for lithium-ion batteries was developed consisting of custom-made ultrathin micrometer-sized glass platelets embedded in a glass fiber nonwoven together with a water-based sodium alginate binder. The physical and electrochemical properties were investigated and compared to commercial polymer-based separators. Full-cell configuration cycling tests at different current rates were performed using graphite and lithium iron phosphate as electrode materials. The glass separator was high-temperature tested and showed a stability up to at least 600 °C without significant shrinking. Furthermore, it showed an exceptional wettability for non-aqueous electrolytes. The electrochemical performance was excellent compared to commercially available polymer-based separators. The results clearly show that glass platelets integrated into a glass fiber nonwoven performs remarkably well as a separator material in lithium-ion batteries and show high-temperature stability.

  14. Engineering Pyrite-Type Bimetallic Ni-Doped CoS2 Nanoneedle Arrays over a Wide Compositional Range for Enhanced Oxygen and Hydrogen Electrocatalysis with Flexible Property

    Guowei He

    2017-11-01

    Full Text Available The development of cheap and efficient catalytic electrodes is of great importance, to promote the sluggish overall water-splitting systems associated with the large-scale application of clean and renewable energy technologies. In this work, we report the controlled synthesis of pyrite-type bimetallic Ni-doped CoS2 nanoneedle (NN arrays supported on stainless steel (SS (designated as NixCo1−xS2 NN/SS, 0 ≤ x ≤ 1 and the related compositional influence on electrocatalytic efficiencies for the oxygen and hydrogen evolution reaction (OER/HER. Impressively, the Ni0.33Co0.67S2 NN/SS displays superior activity and faster kinetics for catalyzing OER (low overpotential of 286 mV at 50 mA cm−2; Tafel value of 55 mV dec−1 and HER (low overpotential of 350 mV at 30 mA cm−2; Tafel value of 76 mV dec−1 than those of counterparts with other Ni/Co ratios and also monometallic Ni- or Co-based sulfides, which is attributed to the optimized balance from the improved electron transfer capability, increased exposure of electrocatalytic active sites, and favorable dissipation of gaseous products over the nanoneedle surface. Furthermore, the conductive, flexible SS support and firmly attached in-situ integrated feature, result in the flexibility and remarkable long-term stability of as-prepared binder-free Ni0.33Co0.67S2 NN/SS electrode. These results demonstrate element-doping could be an efficient route at the atomic level to design new materials and further optimize the surface physicochemical properties for enhancing the overall electrochemical water splitting activity.

  15. Flexible Automation System for Determination of Elemental Composition of Incrustations in Clogged Biliary Endoprostheses Using ICP-MS.

    Fleischer, Heidi; Ramani, Kinjal; Blitti, Koffi; Roddelkopf, Thomas; Warkentin, Mareike; Behrend, Detlef; Thurow, Kerstin

    2018-02-01

    Automation systems are well established in industries and life science laboratories, especially in bioscreening and high-throughput applications. An increasing demand of automation solutions can be seen in the field of analytical measurement in chemical synthesis, quality control, and medical and pharmaceutical fields, as well as research and development. In this study, an automation solution was developed and optimized for the investigation of new biliary endoprostheses (stents), which should reduce clogging after implantation in the human body. The material inside the stents (incrustations) has to be controlled regularly and under identical conditions. The elemental composition is one criterion to be monitored in stent development. The manual procedure was transferred to an automated process including sample preparation, elemental analysis using inductively coupled plasma mass spectrometry (ICP-MS), and data evaluation. Due to safety issues, microwave-assisted acid digestion was executed outside of the automation system. The performance of the automated process was determined and validated. The measurement results and the processing times were compared for both the manual and the automated procedure. Finally, real samples of stent incrustations and pig bile were analyzed using the automation system.

  16. Complete dechlorination of 2,4-dichlorophenol in aqueous solution on palladium/polymeric pyrrole-cetyl trimethyl ammonium bromide/foam-nickel composite electrode

    Sun, Zhirong, E-mail: zrsun@bjut.edu.cn [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Wei, Xuefeng; Han, Yanbo; Tong, Shan [College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China); Hu, Xiang, E-mail: huxiang99@163.com [College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2013-01-15

    Highlights: ► Pd/PPy-CTAB/foam-Ni electrode with high surface area and low Pd content was prepared. ► The composite electrode was applied to dechlorination of 2,4-DCP in aqueous solution. ► Complete dechlorination of 2,4-DCP was achieved with higher current efficiency. ► Removal efficiency kept 100% after 10 times dechlorination on the stable electrode. ► The electrochemically reductive activation energy was 25.8 kJ mol{sup −1} in this system. -- Abstract: The electrochemically reductive dechlorination of 2,4-dichlorophenol (2,4-DCP) in aqueous solution on palladium/polymeric pyrrole-cetyl trimethyl ammonium bromide/foam-nickel electrode (Pd/PPy-CTAB/foam-Ni electrode) was investigated in this paper. Pd/PPy-CTAB/foam-Ni electrode was prepared and characterized by cyclic voltammetry (CV), scanning electron microscope (SEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The influences of some experimental factors such as the dechlorination current, dechlorination time and the initial pH on the removal efficiency and the current efficiency of 2,4-DCP dechlorination on Pd/PPy-CTAB/foam-Ni electrode were studied. Complete removal of 2,4-DCP was achieved and the current efficiency of 47.4% could be obtained under the conditions of the initial pH of 2.2, the dechlorination current of 5 mA and the dechlorination time of 50 min when the initial 2,4-DCP concentration was 100 mg L{sup −1}. The analysis of high performance liquid chromatography (HPLC) identified that the intermediate products were 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP). The final products were mainly phenol. Its further reduction product cyclohexanone was also detected. The electrocatalytic dechlorination pathways of 2,4-DCP on Pd/PPy-CTAB/foam-Ni electrode were discussed. The stability of the electrode was favorable that it could keep dechlorination efficiency at 100% after having been reused

  17. Conflicting flexibility

    De Jong, P.; Schaap, A.

    2011-01-01

    New buildings are designed for first users. For a sustainable approach there are many advantages in designing in flexibility and adjustability in order to enable and facilitate the other sequential users. For the first investor this flexibility is translated into improved exit values due to

  18. Flexible two-ply yarn supercapacitors based on carbon nanotube/stainless steel core spun yarns decorated with Co3O4 nanoparticles and MnOx composites

    Su, Fenghua; Lyu, Xiaoming; Liu, Cansen; Miao, Menghe

    2016-01-01

    Highlights: • Carbon nanotube/stainless steel core-sheath yarns as electrode for two-ply supercapacitor. • The yarns were decorated with Co 3 O 4 nanoparticles and MnO x composites. • Yarn electrodes deposited on Co 3 O 4 and MnO x have excellent specific capacitance. • The two-ply yarn supercapacitor based on MnO x has high energy density and power density. • The yarn supercapacitors are highly flexible and strong for wearable electronics. - Abstract: High performance two-ply yarn supercapacitors are fabricated by electrodeposition of transition metal oxide pseudocapacitive materials on carbon nanotube/stainless steel (CNT/SS) core spun yarns. The SS core incorporated in the carbon nanotube yarn has dramatically improved the conductivity of the substrate and the efficiency of electrodeposition of metal oxides on the electrodes. The SS core acts as current collector in the final two-ply yarn supercapacitors with significantly improved specific capacitance and up-scaled length of supercapacitors. Manganese oxide and cobalt oxide electrodeposited on as-spun CNT/SS yarn are compared for their electrochemical performance in two-ply yarn supercapacitors. Both supercapacitors displayed improvement in capacitance, energy and power densities, especially MnO x /CNT/SS yarn supercapacitor. The solid-state supercapacitor based on MnO x /CNT/SS composite yarn shows excellent electrochemical properties with a specific capacitance of 217.61 F/cm 3 at 0.02 V/s and an energy density of 4.84 mWh/cm 3 at a power density of 435.22 mW/cm 3 .

  19. Vieillissement du polyamide 11 utilisé dans les conduites flexibles : influence de la composition du fluide transporté Influence of the Chemical Nature of the Environment on the Aging of Polyamide 11 Used for Offshore Flexible Pipes

    Ubrich E.

    2006-11-01

    Full Text Available Le polyamide 11 est utilisé comme gaine d'étanchéité interne des conduites flexibles de transport de produits pétroliers. Dans certaines conditions d'utilisation, celui-ci subit une dégradation de ses propriétés mécaniques et physico-chimiques initiales. Des échanges de matières s'établissent entre le matériau et le fluide transporté : des composés constitutifs du fluide (eau, hydrocarbures peuvent être absorbés par le polyamide tandis que le principal additif du matériau (le plastifiant est extrait. Cette étude, entreprise pour déterminer l'influence de la composition du milieu chimique sur les propriétés du polyamide 11, a permis : 1 De développer une nouvelle méthode d'analyse des matières diffusant dans le polyamide 11. Le principe de cette méthode consiste à réaliser une thermodésorption des différentes matières présentes dans le polymère et à les analyser en ligne par spectrométrie de masse à moyenne résolution (résolution = 3000. Cette méthode permet l'analyse quantitative simultanée du plastifiant résiduel, de l'eau et des hydrocarbures absorbés ainsi que la détermination de la répartition par familles chimiques de ces hydrocarbures. 2 De proposer un modèle prédictif du vieillissement du polyamide 11 dans des milieux modèles constitués d'eau, d'une coupe gazole principalement aliphatique et d'une coupe gazole principalement aromatique. La composition de ces différents milieux de vieillissement a été choisie à l'aide d'un plan d'expériences appliqué aux mélanges. L'influence de l'eau sur les propriétés mécaniques (diminution de l'allongement à la rupture et physico-chimiques (diminution de la masse moléculaire moyenne et augmentation du taux de cristallinité a été mise en évidence. Par ailleurs, quel que soit le milieu de vieillissement, à 140°C, le plastifiant est extrait du polyamide. L'influence du milieu aromatique sur la plastification du matériau a été d

  20. Composition and biological activities of the aqueous extracts of three scleractinian corals from the Mexican Caribbean: Pseudodiploria strigosa, Porites astreoides and Siderastrea siderea.

    García-Arredondo, Alejandro; Rojas-Molina, Alejandra; Ibarra-Alvarado, César; Lazcano-Pérez, Fernando; Arreguín-Espinosa, Roberto; Sánchez-Rodríguez, Judith

    2016-01-01

    Scleractinian corals (stony corals) are the most abundant reef-forming cnidarians found in coral reefs throughout the world. Despite their abundance and ecological importance, information about the diversity of their toxins and their biological activities is very scarce. In this study, the chemical composition and the biological activities of the aqueous extracts of Pseudodiploria strigosa , Porites astreoides and Siderastrea siderea , three scleractinian corals from the Mexican Caribbean, have been assessed for the first time. Toxicity of the extracts was assessed in crickets; the presence of cytolysins was detected by the hemolysis assay; the vasoconstrictor activity was determined by the isolated rat aortic ring assay; the nociceptive activity was evaluated by the formalin test. The presence of phospholipases A 2 (PLA 2 ), serine proteases, and hyaluronidases was determined by enzymatic methods. Low-molecular-weight fractions were obtained by gel filtration chromatography and ultrafiltration. Extracts from the three species were toxic to crickets, induced hemolysis in human and rat erythrocytes, produced vasoconstriction on isolated rat aortic rings, and presented phospholipase A 2 and serine-protease activity. Despite the fact that these corals are not considered to be harmless to humans, the extracts generated significant nociceptive responses. The matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry analysis of the low-molecular-weight fractions revealed the presence of peptides within a mass range of 3000 to 6000 Da. These fractions were toxic to crickets and two of them induced a transitory vasoconstrictor effect on isolated rat aortic rings. This study suggests that scleractinian corals produce low-molecular-weight peptides that are lethal to crickets and induce vasoconstriction.

  1. On the synthesis of a bio-inspired dual-cellular fluidic flexible matrix composite adaptive structure based on a non-dimensional dynamics model

    Li, Suyi; Wang, K W

    2013-01-01

    A recent study investigated the dynamic characteristics of an adaptive structure concept featuring dual fluidic flexible matrix composite (F 2 MC) cells inspired by the configuration of plant cells and cell walls. This novel bio-inspired system consists of two F 2 MC cells with different fiber angles connected through internal fluid circuits. It was discovered that the dual F 2 MC cellular structure can be characterized as a two degree of freedom damped mass–spring oscillator, and can be utilized as a vibration absorber or an enhanced actuator under different operation conditions. These results demonstrated that the concept is promising and further investigations are needed to develop methodologies for synthesizing future multi-cellular F 2 MC structural systems. While interesting, the previous study focused on specific case studies and analysis. That is, the outcome did not provide insight that could be generalized, or tools for synthesizing a multiple F 2 MC cellular structure. This paper attempts to address this important issue by developing a non-dimensional dynamic model, which reveals good physical insights as well as identifying crucial constitutive parameters for F 2 MC cellular design. Working with these parameters, rather than physical variables, can greatly simplify the mathematics involved in the study. A synthesis tool is then developed for the dual-cellular structure, and it is found that for each set of achievable target poles and zero, there exist multiple F 2 MC cellular designs, forming a design space. The presented physical insights and synthesis tool for the dual-cellular structure will be the building blocks for future investigation on cellular structures with a larger number of cells. (paper)

  2. Composites

    Kasen, M.B.

    1983-01-01

    This chapter discusses the roles of composite laminates and aggregates in cryogenic technology. Filamentary-reinforced composites are emphasized because they are the most widely used composite materials. Topics considered include composite systems and terminology, design and fabrication, composite failure, high-pressure reinforced plastic laminates, low-pressure reinforced plastics, reinforced metals, selectively reinforced structures, the effect of cryogenic temperatures, woven-fabric and random-mat composites, uniaxial fiber-reinforced composites, composite joints in cryogenic structures, joining techniques at room temperature, radiation effects, testing laminates at cryogenic temperatures, static and cyclic tensile testing, static and cyclic compression testing, interlaminar shear testing, secondary property tests, and concrete aggregates. It is suggested that cryogenic composite technology would benefit from the development of a fracture mechanics model for predicting the fitness-for-purpose of polymer-matrix composite structures

  3. Natural flexible dermal armor.

    Yang, Wen; Chen, Irene H; Gludovatz, Bernd; Zimmermann, Elizabeth A; Ritchie, Robert O; Meyers, Marc A

    2013-01-04

    Fish, reptiles, and mammals can possess flexible dermal armor for protection. Here we seek to find the means by which Nature derives its protection by examining the scales from several fish (Atractosteus spatula, Arapaima gigas, Polypterus senegalus, Morone saxatilis, Cyprinius carpio), and osteoderms from armadillos, alligators, and leatherback turtles. Dermal armor has clearly been developed by convergent evolution in these different species. In general, it has a hierarchical structure with collagen fibers joining more rigid units (scales or osteoderms), thereby increasing flexibility without significantly sacrificing strength, in contrast to rigid monolithic mineral composites. These dermal structures are also multifunctional, with hydrodynamic drag (in fish), coloration for camouflage or intraspecies recognition, temperature and fluid regulation being other important functions. The understanding of such flexible dermal armor is important as it may provide a basis for new synthetic, yet bioinspired, armor materials. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Flexible magnetoimpedance sensor

    Li, Bodong

    2015-03-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors\\'s magnetic field and frequency responses and their dependence on the sensors\\'s deflection. For the first time, the impedance characteristic is obtained through reflection coefficient analysis over a wide range of frequencies from 0.1 MHz to 3 GHz and for deflections ranging from zero curvature to a radius of 7.2 cm. The sensor element maintains a high MI ratio of up to 90% and magnetic sensitivity of up to 9.2%/Oe over different bending curvatures. The relationship between the curvature and material composition is discussed based on the magnetostriction effect and stress simulations. The sensor\\'s large frequency range, simple fabrication process and high sensitivity provide a great potential for flexible electronics and wireless applications.

  5. Flexible magnetoimpedance sensor

    Li, Bodong; Kavaldzhiev, Mincho N.; Kosel, Jürgen

    2015-01-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors's magnetic field and frequency responses and their dependence on the sensors's deflection. For the first time, the impedance characteristic is obtained through reflection coefficient analysis over a wide range of frequencies from 0.1 MHz to 3 GHz and for deflections ranging from zero curvature to a radius of 7.2 cm. The sensor element maintains a high MI ratio of up to 90% and magnetic sensitivity of up to 9.2%/Oe over different bending curvatures. The relationship between the curvature and material composition is discussed based on the magnetostriction effect and stress simulations. The sensor's large frequency range, simple fabrication process and high sensitivity provide a great potential for flexible electronics and wireless applications. - Highlights: • A flexible magnetoimpedance (MI) sensor is developed. • Studies are carried out using a flexible microstrip transmission line. • An MI ratio of up to 90% is obtained. • The effect of magnetostriction is studied

  6. Workplace flexibility.

    Scordato, C; Harris, J

    1990-01-01

    Whether your organization is in a growth pattern or downsizing, you are probably facing change. To gain some insight into your options, here is an in-depth look at the problems and benefits of some flexible work arrangements from a just published study by Catalyst.

  7. Flexibility conflict?

    Delsen, L.W.M.; Bauer, F.; Groß, H.; Sieglen, G.

    2002-01-01

    The chapter deals with the presupposed conflict of interests between employers and employees resulting from a decoupling of operating hours and working times. It starts from the notion that both long operating hours and flexibility are relative concepts. As there is some discretion, the ultimate

  8. Preclinical evaluation of the effect of the combined use of the Ethicon Securestrap® Open Absorbable Strap Fixation Device and Ethicon Physiomesh™ Open Flexible Composite Mesh Device on surgeon stress during ventral hernia repair

    Sutton N

    2017-12-01

    Full Text Available Nadia Sutton,1 Melinda H MacDonald,2 John Lombard,1 Bodgan Ilie,3 Piet Hinoul,4 Douglas A Granger5,6 1Global Health Economics and Market Access, Johnson & Johnson Medical Devices, New Brunswick, NJ, USA; 2Preclinical Center of Excellence, Johnson & Johnson Medical Devices Companies, Somerville, NJ, USA; 3Biostatistics, Ethicon, Somerville, NJ, USA; 4Medical Affairs, Ethicon, Somerville, NJ, USA; 5Institute for Interdisciplinary Salivary Bioscience Research (IISBR, University of California at Irvine, Irvine, CA, USA; 6Johns Hopkins University School of Nursing, Bloomberg School of Public Health, and School of Medicine, Baltimore, MD, USA Aim: To evaluate whether performing ventral hernia repairs using the Ethicon Physiomesh™ Open Flexible Composite Mesh Device in conjunction with the Ethicon Securestrap® Open Absorbable Strap Fixation Device reduces surgical time and surgeon stress levels, compared with traditional surgical repair methods. Methods: To repair a simulated ventral incisional hernia, two surgeries were performed by eight experienced surgeons using a live porcine model. One procedure involved traditional suture methods and a flat mesh, and the other procedure involved a mechanical fixation device and a skirted flexible composite mesh. A Surgery Task Load Index questionnaire was administered before and after the procedure to establish the surgeons’ perceived stress levels, and saliva samples were collected before, during, and after the surgical procedures to assess the biologically expressed stress (cortisol and salivary alpha amylase levels. Results: For mechanical fixation using the Ethicon Physiomesh Open Flexible Composite Mesh Device in conjunction with the Ethicon Securestrap Open Absorbable Strap Fixation Device, surgeons reported a 46.2% reduction in perceived workload stress. There was also a lower physiological reactivity to the intraoperative experience and the total surgical procedure time was reduced by 60

  9. Composition

    Bergstrøm-Nielsen, Carl

    2011-01-01

    Strategies are open compositions to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them in full...

  10. Composition

    2014-01-01

    Memory Pieces are open compositions to be realised solo by an improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them...

  11. Influence of age, sexual maturation, anthropometric variables and body composition on flexibility DOI:10.5007/1980-0037.2010v12n3p151

    Giseli Minatto

    2010-01-01

    Full Text Available Since flexibility is an important component of health-related physical fitness at all ages, this parameter should be evaluated in children and adolescents because the ability to acquire and maintain levels of flexibility is greater in this age group. Thus, the objective of this study was to evaluate body weight, height, BMI and flexibility according to chronological age and sexual maturation and to determine the influence of these variables on flexibility in students from public and private schools. A cross-sectional descriptive and analytical study was conducted. The sample consisted of 2604 girls aged 8 to 17 years. Body weight, height, BMI, sexual maturation, and flexibility were evaluated. The data were analyzed descriptively using the following inferential tests: two-way analysis of variance (ANOVA followed by the Tukey post-hoc test, Pearson’s and Spearman’s simple correlation coefficients, and stepwise multiple regression analysis. The SPSS® 13.0 program was used for all statistical analyses, with a level of significance of p< 0.05. Significant differences with increasing age and maturation stage were observed for the variables body weight, height and BMI when compared to the subsequent year. In conclusion, body wei-ght and height increased with increasing age, especially between 8 and 13 years, and flexibility remained stable throughout childhood and adolescence.

  12. Flexible licensing

    Martyn Jansen

    2012-07-01

    Full Text Available The case is presented for a more flexible approach to licensing online library resources. Today's distributed education environment creates pressure for UK higher and further education institutions (HEI/FEIs to form partnerships and to develop educational products and roll them out across the globe. Online library resources are a key component of distributed education and yet existing licensing agreements struggle to keep pace with the increasing range of users and purposes for which they are required. This article describes the process of developing a flexible approach to licensing and proposes a new model licence for online library resources which has the adaptability needed in this new global educational landscape. These ideas have been presented and discussed at various workshops across Eduserv's and JISC Collections' higher education and publisher communities, and further consultation is ongoing.

  13. Inkjet printing of conjugated polymer precursors on paper substrates for colorimetric sensing and flexible electrothermochromic display.

    Yoon, Bora; Ham, Dae-Young; Yarimaga, Oktay; An, Hyosung; Lee, Chan Woo; Kim, Jong-Man

    2011-12-08

    Inkjet-printable aqueous suspensions of conjugated polymer precursors are developed for fabrication of patterned color images on paper substrates. Printing of a diacetylene (DA)-surfactant composite ink on unmodified paper and photopaper, as well as on a banknote, enables generation of latent images that are transformed to blue-colored polydiacetylene (PDA) structures by UV irradiation. Both irreversible and reversible thermochromism with the PDA printed images are demonstrated and applied to flexible and disposable sensors and to displays. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Preparation of 2-acrylamido-2 methyl propane-1-sulfonic acid/bentonite composite by radiation polymerization for adsorption of basic violet dye from aqueous solution

    Sokker, H.H.; Younes, M.M.; Abdel-Kareem, M.; Zohdy, K.

    2010-01-01

    Water uptake and the sorption properties of composite made by radiation polymerization of 2-acrylamido-2- methyl propane -1-sulfonic acid (AMPS) and a clay such as bentonite were investigated as a function of composition (2,6 and 10% w.t %) of bentonite and radiation dose. The prepared composite was characterized by FTIR and SEM. Swelling experiments were performed in water at 25 degree C. The prepared composite was applied for adsorption of basic violet dye at different ph values and the results showed that the prepared composite of composition (10% wt % of bentonite) showed the highest removal percent of basic violet dye at ph=9 compared with other compositions. Also, the adsorption capacity of basic violet at ph 3,7 and 9 were 3.5, 9 and 50 mg/g, respectively. The adsorption process of basic violet follows both Freundlich and Langmuir models and followed pseudo second order kinetic model

  15. Flow of Aqueous Humor

    ... Home Flow of Aqueous Humor Flow of Aqueous Humor Most, but not all, forms of glaucoma are ... remains normal when some of the fluid (aqueous humor) produced by the eye's ciliary body flows out ...

  16. Asymmetric Flexible Supercapacitor Stack

    Leela Mohana Reddy A

    2008-01-01

    Full Text Available AbstractElectrical double layer supercapacitor is very significant in the field of electrical energy storage which can be the solution for the current revolution in the electronic devices like mobile phones, camera flashes which needs flexible and miniaturized energy storage device with all non-aqueous components. The multiwalled carbon nanotubes (MWNTs have been synthesized by catalytic chemical vapor deposition technique over hydrogen decrepitated Mischmetal (Mm based AB3alloy hydride. The polymer dispersed MWNTs have been obtained by insitu polymerization and the metal oxide/MWNTs were synthesized by sol-gel method. Morphological characterizations of polymer dispersed MWNTs have been carried out using scanning electron microscopy (SEM, transmission electron microscopy (TEM and HRTEM. An assymetric double supercapacitor stack has been fabricated using polymer/MWNTs and metal oxide/MWNTs coated over flexible carbon fabric as electrodes and nafion®membrane as a solid electrolyte. Electrochemical performance of the supercapacitor stack has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

  17. Flexible Consumption

    Holm Jacobsen, Peter; Pallesen, Trine

    This report presents the first findings from our qualitative study of consumer behaviour vis-à-vis flexible consumption. The main of objective of this report is to present our first round of data from Bornholm, and to assist the design of products/services designed in WP6. In the report, we adopt...... the perspective of the consumer: what does living in a demand response setup look like to participants – and what kinds of behaviour and interest motivate – and emerge from – their participation in EcoGrid 2.0....

  18. Flexible Capitalism

    Approaching “work” as at heart a practice of exchange, this volume explores sociality in work environments marked by the kind of structural changes that have come to define contemporary “flexible” capitalism. It introduces anthropological exchange theory to a wider readership, and shows how...... the perspective offers new ways to enquire about the flexible capitalism’s social dimensions. The essays contribute to a trans-disciplinary scholarship on contemporary economic practice and change by documenting how, across diverse settings, “gift-like” socialities proliferate, and even sustain the intensified...

  19. A Difference in Fatty Acid Composition of Isocaloric High-Fat Diets Alters Metabolic Flexibility in Male C57BL/6JOlaHsd Mice

    Duivenvoorde, L. P. M.; van Schothorst, E. M.; Swarts, H. M.; Kuda, Ondřej; Steenbergh, E.; Termeulen, S.; Kopecký, Jan; Keijer, J.

    2015-01-01

    Roč. 10, č. 6 (2015), e0128515 E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) 7E10059 Institutional support: RVO:67985823 Keywords : PUFA * satureted fatty acids * high fat diet * metabolic flexibility * indirect calorimetry Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 3.057, year: 2015

  20. Performance and mechanisms for the removal of phthalates and pharmaceuticals from aqueous solution by graphene-containing ceramic composite tubular membrane coupled with the simultaneous electrocoagulation and electrofiltration process.

    Yang, Gordon C C; Chen, Ying-Chun; Yang, Hao-Xuan; Yen, Chia-Heng

    2016-07-01

    In this study, commonly detected emerging contaminants (ECs) in water, including di-n-butyl phthalate (DnBP), di(2-ethylhexyl) phthalate (DEHP), cephalexin (CLX), sulfamethoxazole (SMX) and caffeine (CAF), were selected as the target contaminants. A lab-prepared graphene-containing ceramic composite tubular membrane (TGCCM) coupled with the simultaneous electrocoagulation and electrofiltration process (EC/EF) in crossflow filtration mode was used to remove target contaminants in model solution. Meanwhile, a comparison of the removal efficiency was made among various tubular composite membranes reported, including carbon fibers/carbon/alumina composite tubular membrane (TCCACM), titania/alumina composite tubular membrane (TTACM) and alumina tubular membrane (TAM). The results of this study showed that the removal efficiencies for DnBP and DEHP were 99%, whereas 32-97% for cephalexin (CLX), sulfamethoxazole (SMX) and caffeine (CAF). In this work the mechanisms involved in removing target ECs were proposed and their roles in removing various ECs were also discussed. Further, two actual municipal wastewaters were treated to evaluate the applicability of the aforementioned treatment technology (i.e., TGCCM coupled with EC/EF) to various aqueous solutions in the real world. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Composition

    Bergstrøm-Nielsen, Carl

    2014-01-01

    Cue Rondo is an open composition to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound/video files will in some cases only provide a few minutes' sample, or the visuals will not appear at all....... Please DOWNLOAD them to see/hear them in full length! This work is licensed under a Creative Commons "by-nc" License. You may for non-commercial purposes use and distribute it, performance instructions as well as specially designated recordings, as long as the author is mentioned. Please see http...

  2. Flexible nanovectors

    Pugno, Nicola M

    2008-01-01

    In this paper we show that the control of adhesion in highly flexible (a property that could be crucial for smart drug delivery but which is still ignored in the literature) nanovectors can help in smartly targeting and delivering the drug. The existence of and the conditions for activating and controlling a super-adhesive state are addressed. Even if such a state has never been observed in nanovectors, our calculations, as well as observations in spiders and geckos, suggest its existence and feasible control. Control of the competition between the drag and the adhesive force is exploited to improve the targeting ability and a hierarchical model is applied to describe a real vasculature. The high flexibility of the nanovector is used to smartly deliver the drug only during adhesion by nanopumping or, as a limiting case, by the new concept of 'adhesion induced nanovector implosion'; a liquid drop analogy is utilized for the calculations. Fast (pumping) and slow (diffusion) drug deliveries can thus be separately controlled by controlling the size and shape of the nanovector. Multiple stage nanovectors are also briefly discussed, mimicking aerospace vector strategies.

  3. Flexible nanovectors

    Pugno, Nicola M.

    2008-11-01

    In this paper we show that the control of adhesion in highly flexible (a property that could be crucial for smart drug delivery but which is still ignored in the literature) nanovectors can help in smartly targeting and delivering the drug. The existence of and the conditions for activating and controlling a super-adhesive state are addressed. Even if such a state has never been observed in nanovectors, our calculations, as well as observations in spiders and geckos, suggest its existence and feasible control. Control of the competition between the drag and the adhesive force is exploited to improve the targeting ability and a hierarchical model is applied to describe a real vasculature. The high flexibility of the nanovector is used to smartly deliver the drug only during adhesion by nanopumping or, as a limiting case, by the new concept of 'adhesion induced nanovector implosion'; a liquid drop analogy is utilized for the calculations. Fast (pumping) and slow (diffusion) drug deliveries can thus be separately controlled by controlling the size and shape of the nanovector. Multiple stage nanovectors are also briefly discussed, mimicking aerospace vector strategies.

  4. One-step preparation of long-term stable and flexible CsPbBr3 perovskite quantum dots/ethylene vinyl acetate copolymer composite films for white LEDs.

    Li, Yang; Lv, Ying; Guo, Ziquan; Dong, Liubing; Zheng, Jianghui; Chai, Chufen; Chen, Nan; Lu, Yijun; Chen, Chao

    2018-04-19

    CsPbBr3 perovskite quantum dots (PQDs)/ethylene vinyl acetate (EVA) composite films were prepared via a one-step method, based on that both supersaturated recrystallization of CsPbBr3 PQDs and dissolution of EVA were realized in toluene. The prepared films display outstanding green emitting performance with high color purity of 92% and photoluminescence quantum yield of 40.5% at appropriate CsPbBr3 PQD loading. They possess long-term stable luminescent properties in the air and in water, benefiting from the effective protection of CsPbBr3 PQDs by EVA matrix. Besides, the prepared CsPbBr3 PQDs/EVA films are flexible enough to be repeatedly bent for 1000 cycles while keeping unchanged photoluminescence intensity. Optical properties of the CsPbBr3 PQDs/EVA films in white LEDs were also studied by experiments and theoretical simulation. Overall, facile preparation process, good long-term stability and high flexibility allow our green-emitting CsPbBr3 PQDs/EVA films to be applied in lighting applications and flexible displays.

  5. New Synthesis of nZVI/C Composites as an Efficient Adsorbent for the Uptake of U(VI) from Aqueous Solutions.

    Liu, Haibo; Li, Mengxue; Chen, Tianhu; Chen, Changlun; Alharbi, Njud S; Hayat, Tasawar; Chen, Dong; Zhang, Qiang; Sun, Yubing

    2017-08-15

    New nanoscale zerovalent iron/carbon (nZVI/C) composites were successfully prepared via heating natural hematite and pine sawdust at 800 °C under nitrogen conditions. Characterization by SEM, XRD, FTIR, and XPS analyses indicated that the as-prepared nZVI/C composites contained a large number of reactive sites. The lack of influence of the ionic strength revealed inner-sphere complexation dominated U(VI) uptake by the nZVI/C composites. Simultaneous adsorption and reduction were involved in the uptake process of U(VI) according to the results of XPS and XANES analyses. The presence of U-C/U-U shells demonstrated that innersphere complexation and surface coprecipitation dominated the U(VI) uptake at low and high pH conditions, respectively. The uptake behaviors of U(VI) by the nZVI/C composites were fitted well by surface complexation modeling with two weak and two strong sites. The maximum uptake capacity of U(VI) by the nZVI/C composites was 186.92 mg/g at pH 4.0 and 328 K. Additionally, the nZVI/C composites presented good recyclability and recoverability for U(VI) uptake in regeneration experiments. These observations indicated that the nZVI/C composites can be considered as potential adsorbents to remove radionuclides for environmental remediation.

  6. Synthesis Of Fe3O4-Chitosan Magnetic NanoComposites By Gamma Irradiation For Absorbing Of Heavy Metals In Aqueous Solutions

    Tran Minh Quynh; Nguyen Van Binh; Nguyen Quang Long; Hoang Dang Sang

    2014-01-01

    Studies on adsorption capacity of the obtained Fe 3 O 4 -chitosan nanoparticles for metal ions in aqueous solutions showed that initial amount of adsorbent and pH have much influenced on their adsorption capacity. Adsorption rate was quite fast at first, then slower. Maximum adsorption capacity were measured at 25 o C are 71, 41.4 and 26 mg/g obtained at pH 5, 6 and 7 for Cu(CH 3 COO) 2 .H 2 O, Pb(CH 3 COO) 2 .3H 2 O and NaH 2 AsO 4 .7H 2 O, respectively. The adsorption capacity increased with adsorbent amount to a certain value, then leveled off. These results suggested that the Fe 3 O 4 -chitosan nanoparticles can be applied as a potential adsorbent for removal of heavy metals from aqueous solution, but it required further studies including of adsorption kinetics and desorption in order to control the process in practice. (author)

  7. Evaluation of CNTs/MnO{sub 2} composite for adsorption of {sup 60}Co(II), {sup 65}Zn(II) and Cd(II) ions from aqueous solutions

    Sharaf El-Deen, Sahar E.A.; Moussa, Saber I.; Mekawy, Zakaria A.; Shehata, Mohamed K.K.; Someda, Hanan H. [Atomic Energy Authority, Inshas (Egypt). Dept. of Nuclear Chemistry; Sadeek, Sadeek A. [Zagazig Univ. (Egypt). Dept. of Chemistry

    2017-03-01

    CNTs/MnO{sub 2} composite was synthesized by a co-precipitation method after preparation of carbon nanotubes (CNTs) using a chemical oxidation method and was characterized using Fourier transformer infrared (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The synthesized CNTs/MnO{sub 2} composite was used as a sorbent for the removal of some radionuclides ({sup 60}Co and {sup 65}Zn-radioisotopes) and Cd (II) ions from aqueous solutions. Different parameters affecting the removal process including pH, contact time and metal ion concentration were investigated. Isotherm and kinetic models were studied. Adsorption data was interpreted in terms of both Freundlich and Langmuir isotherms and indicated that the CNTs/MnO{sub 2} composite complied well with both Langmuir and Freundlich models for {sup 60}Co and Cd(II) ions and with the Freundlich model only for the {sup 65}Zn radioisotope. A pseudo-second-order model was effectively employed to describe the adsorption behavior of {sup 60}Co, {sup 65}Zn and Cd(II) ions. Desorption of {sup 60}Co and {sup 65}Zn and Cd(II) ions from loaded samples was studied using different eluents.

  8. Flexible Work Schedules. ERIC Digest.

    Kerka, Sandra

    Flexible work schedules are one response to changes in the composition of the work force, new life-styles, and changes in work attitudes. Types of alternative work schedules are part-time and temporary employment, job sharing, and flextime. Part-time workers are a diverse group--women, the very young, and older near-retirees. Although part-time…

  9. Effect of Aqueous Ammonia Soaking on the methane yield and composition of digested manure fibers applying different ammonia concentrations and treatment durations

    Mirtsou-Xanthopoulou, Chrysoula; Jurado, Esperanza; Skiadas, Ioannis

    2014-01-01

    , their economical profitable operation relies on increasing the methane yield from manure, and especially of its solid fraction which is not so easily degradable. In the present study, Aqueous Ammonia Soaking (AAS) in six different concentrations in ammonia (5%, 10%, 15%, 20%, 25% and 32%) and for 1, 3 and 5 days...... at 22°C was applied on digested fibers separated from the effluent of a manure-fed, full-scale anaerobic digester. A methane yield increase from 76% to 104% was achieved during the first series of experiments, while the difference in reagent concentration did not considerably affect the methane yield...... is a very promising treatment resulting to an overall increase of the methane yield of digested manure fibers from 76 to 265% depending on the conditions and the batch of digested fibers used (an even higher increase of 190-265% was achieved during the 2nd series of experiments, where different AAS...

  10. Flexible benefit plans in Dutch organisations

    Hillebrink, C.

    2006-01-01

    Flexible benefit plans give employees a greater say over the composition of their benefits than traditional Dutch benefit plans. These arrangements developed in a time of further individualisation, increasing flexibility in the workplace, and a tight labour market in the Netherlands. By giving employees a choice in the way they are paid, employers hoped to become more attractive employers, and lend a helping hand to employees who were combining work and care. In this study, flexible benefit p...

  11. Synthesis and supercapacitor electrode of VO{sub 2}(B)/C core–shell composites with a pseudocapacitance in aqueous solution

    Zhang, Yifu, E-mail: yfzhang@dlut.edu.cn; Zheng, Jiqi; Hu, Tao; Tian, Fuping; Meng, Changgong

    2016-05-15

    Highlights: • A facile one-pot hydrothermal method was used to synthesize VO{sub 2}(B)/C core–shell composites. • VO{sub 2}(B)/C composites consisted of the crystal VO{sub 2}(B) phase and the amorphous carbon phase. • The supercapacitor property of VO{sub 2}(B)/C composites was improved by this novel structure. - Abstract: VO{sub 2}(B)/C core–shell composites were successfully prepared using commercial V{sub 2}O{sub 5}, glucose and water as the starting materials by a facile one-pot hydrothermal method. The composition of the products was characterized by the techniques including X-ray powder diffraction, infrared spectroscopy, Raman, energy-dispersive X-ray spectrometer and elemental analysis. The morphology of the products was observed by scanning electron microscopy and transmission electron microscopy tests. The results showed the products consisted of the crystal VO{sub 2}(B) phase and the amorphous carbon phase. The amorphous carbon contained lots of organic groups, such as −OH, C−H, C=O and C=C, etc., which suggested that the carbon here was organic carbon. The morphology of the as-obtained VO{sub 2}(B)/C composites was well-defined nanobelts, and each VO{sub 2}(B) core was encapsulated into carbon. Furthermore, the electrochemical properties of VO{sub 2}(B)/C core–shell composites were investigated by cyclic voltammetry and galvanostatic charge–discharge. The results showed the measured capacitance of VO{sub 2}(B)/C composites was mainly based on the pseudocapacitance. VO{sub 2}(B)/C composites displayed the specific capacitance of 203, 190, 182, 173, 164, and 147 F g{sup −1} at the current density of 0.2, 0.5, 1, 5, 10 and 20 A g{sup −1}, respectively. They also showed an excellent energy density of 198.9 W h kg{sup −1} at a power density of 504.5 W kg{sup −1} and a rapidly reversible redox Faraday response.

  12. In-situ synthesis of SiO2@MOF composites for high-efficiency removal of aniline from aqueous solution

    Han, Tongtong; Li, Caifeng; Guo, Xiangyu; Huang, Hongliang; Liu, Dahuan; Zhong, Chongli

    2016-12-01

    A series of SiO2@aluminum-MOF(MIL-68) composites with different SiO2 loadings have been synthesized by a simple and mild compositing strategy for high-efficiency removal of aniline. As evidenced from SEM and TEM images as well as the particle size distribution, the incorporation of SiO2 can improve the dispersity of MIL-68(Al) in composites, and result in the smaller particle size than that of pristine MIL-68(Al). Besides, the adsorption of aniline over SiO2, MIL-68(Al), the physical mixture of these two materials, and SiO2@MIL-68(Al) composites was investigated comparatively, demonstrating a relatively high adsorption capacity (531.9 mg g-1) of 7% SiO2@MIL-68(Al) towards aniline. Combining the ultrafast adsorption dynamics (reaching equilibrium within 40 s) and great reusability, 7% SiO2@MIL-68(Al) shows excellent adsorption performance. This indicates that the SiO2@MIL-68(Al) composites possess great potential applications as a kind of fascinating adsorbent in water pollution protection.

  13. Flexible benefit plans in Dutch organisations

    Hillebrink, C.

    2006-01-01

    Flexible benefit plans give employees a greater say over the composition of their benefits than traditional Dutch benefit plans. These arrangements developed in a time of further individualisation, increasing flexibility in the workplace, and a tight labour market in the Netherlands. By giving

  14. In-situ growth of high-performance all-solid-state electrode for flexible supercapacitors based on carbon woven fabric/ polyaniline/ graphene composite

    Lin, Yingxi; Zhang, Haiyan; Deng, Wentao; Zhang, Danfeng; Li, Na; Wu, Qibai; He, Chunhua

    2018-04-01

    For the development of wearable electronic devices, it is crucial to develop energy storage components combining high-capacity and flexibility. Herein, an all-solid-state supercapacitor is prepared through an in-situ "growth and wrapping" method. The electrode contains polyaniline deposited on a carbon woven fabric and wrapped with a graphene-based envelop. The hybrid electrode exhibits excellent mechanical and electrochemical performance. The optimized few layer graphene wrapping layer provides for a conductive network, which effectively enhances the cycling stability as 88.9% of the starting capacitance is maintained after 5000 charge/discharge cycles. Furthermore, the assembled device delivers a high areal capacity (of 790 F cm-2) at the current density of 1 A cm-2, a high areal energy (28.21 uWh cm-2) at the power densities of 0.12 mW cm-2 and shows no significant decrease in the performance with a bending angle of 180°. This unique flexible supercapacitor thus exhibits great potential for wearable electronics.

  15. Blending effect of 6,13-bis(triisopropylsilylethynyl) pentacene–graphene composite layers for flexible thin film transistors with a polymer gate dielectric

    Basu, Sarbani; Adriyanto, Feri; Wang, Yeong-Her

    2014-01-01

    Solution processible poly(4-vinylphenol) is employed as a transistor dielectric material for low cost processing on flexible substrates at low temperatures. A 6,13-bis (triisopropylsilylethynyl) (TIPS) pentacene–graphene hybrid semiconductor is drop cast to fabricate bottom-gate and bottom-contact field-effect transistor devices on flexible and glass substrates under an ambient air environment. A few layers of graphene flakes increase the area in the conduction channel, and form bridge connections between the crystalline regions of the semiconductor layer which can change the surface morphology of TIPS pentacene films. The TIPS pentacene–graphene hybrid semiconductor-based organic thin film transistors (OTFTs) cross-linked with a poly(4-vinylphenol) gate dielectric exhibit an effective field-effect mobility of 0.076 cm 2  V −1  s −1 and a threshold voltage of −0.7 V at V gs = −40 V. By contrast, typical TIPS pentacene shows four times lower mobility of 0.019 cm 2  V −1  s −1 and a threshold voltage of 5 V. The graphene/TIPS pentacene hybrids presented in this paper can enhance the electrical characteristics of OTFTs due to their high crystallinity, uniform large-grain distribution, and effective reduction of crystal misorientation of the organic semiconductor layer, as confirmed by x-ray diffraction spectroscopy, atomic force microscopy, and optical microscopy studies. (paper)

  16. Blending effect of 6,13-bis(triisopropylsilylethynyl) pentacene-graphene composite layers for flexible thin film transistors with a polymer gate dielectric.

    Basu, Sarbani; Adriyanto, Feri; Wang, Yeong-Her

    2014-02-28

    Solution processible poly(4-vinylphenol) is employed as a transistor dielectric material for low cost processing on flexible substrates at low temperatures. A 6,13-bis (triisopropylsilylethynyl) (TIPS) pentacene-graphene hybrid semiconductor is drop cast to fabricate bottom-gate and bottom-contact field-effect transistor devices on flexible and glass substrates under an ambient air environment. A few layers of graphene flakes increase the area in the conduction channel, and form bridge connections between the crystalline regions of the semiconductor layer which can change the surface morphology of TIPS pentacene films. The TIPS pentacene-graphene hybrid semiconductor-based organic thin film transistors (OTFTs) cross-linked with a poly(4-vinylphenol) gate dielectric exhibit an effective field-effect mobility of 0.076 cm(2) V(-1) s(-1) and a threshold voltage of -0.7 V at V(gs) = -40 V. By contrast, typical TIPS pentacene shows four times lower mobility of 0.019 cm(2) V(-1) s(-1) and a threshold voltage of 5 V. The graphene/TIPS pentacene hybrids presented in this paper can enhance the electrical characteristics of OTFTs due to their high crystallinity, uniform large-grain distribution, and effective reduction of crystal misorientation of the organic semiconductor layer, as confirmed by x-ray diffraction spectroscopy, atomic force microscopy, and optical microscopy studies.

  17. Synthesis and characterization of polyacrylic acid- grafted-carboxylic graphene/titanium nanotube composite for the effective removal of enrofloxacin from aqueous solutions: Adsorption and photocatalytic degradation studies.

    Anirudhan, Thayyath S; Shainy, F; Christa, J

    2017-02-15

    Polyacrylic acid-grafted-carboxylic graphene/titanium nanotube (PAA-g-CGR/TNT) composite was synthesized. It was effectively used as adsorbent as well as photocatalyst. The composite was characterized by FTIR, XRD, SEM, TEM, Surface Area Analyzer, XPS and DRS. The photocatalytic activity of PAA-g-CGR/TNT composite was evaluated on the basis of the degradation of pollutants by using sunlight. The band gap of the prepared photocatalyst was found to be 2.6eV. The removal of the antibiotic enrofloxacin (ENR) was achieved by two step mechanism based on adsorption and photodegradation. The maximum adsorption was observed at pH 5.0. The best fitted kinetic model was found to be pseudo-second-order. The maximum adsorption was observed at 30°C. The maximum adsorption capacity was found to be 13.40mg/g. The kinetics of photodegradation of ENR onto PAA-g-CGR/TNT composite follow first-order kinetics and optimum pH was found to be 5.0. The regeneration and reuse of the adsorbent-cum-photocatalyst were also examined upto five cycles. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Graphene-Derivatized Silica Composite as Solid-Phase Extraction Sorbent Combined with GC–MS/MS for the Determination of Polycyclic Musks in Aqueous Samples

    Cheng Li

    2018-02-01

    Full Text Available Polycyclic musks (PCMs have recently received growing attention as emerging contaminants because of their bioaccumulation and potential ecotoxicological effects. Herein, an effective method for the determination of five PCMs in aqueous samples is presented. Reduced graphene oxide-derivatized silica (rGO@silica particles were prepared from graphene oxide and aminosilica microparticles and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. PCMs were preconcentrated using rGO@silica as the solid-phase extraction sorbent and quantified by gas chromatography–tandem mass spectrometry. Several experimental parameters, such as eluent, elution volume, sorbent amount, pH, and sample volume were optimized. The correlation coefficient (R ranged from 0.9958 to 0.9992, while the limits of detection and quantitation for the five PCMs were 0.3–0.8 ng/L and 1.1–2.1 ng/L, respectively. Satisfactory recoveries were obtained for tap water (86.6–105.9% and river water samples (82.9–107.1%, with relative standard deviations <10% under optimal conditions. The developed method was applied to analyze PCMs in tap and river water samples from Beijing, China. Galaxolide (HHCB and tonalide (AHTN were the main PCM components detected in one river water sample at concentrations of 18.7 for HHCB, and 11.7 ng/L for AHTN.

  19. Microwave-assisted aqueous enzymatic extraction of oil from pumpkin seeds and evaluation of its physicochemical properties, fatty acid compositions and antioxidant activities.

    Jiao, Jiao; Li, Zhu-Gang; Gai, Qing-Yan; Li, Xiao-Juan; Wei, Fu-Yao; Fu, Yu-Jie; Ma, Wei

    2014-03-15

    Microwave-assisted aqueous enzymatic extraction (MAAEE) of pumpkin seed oil was performed in this study. An enzyme cocktail comprised of cellulase, pectinase and proteinase (w/w/w) was found to be the most effective in releasing oils. The highest oil recovery of 64.17% was achieved under optimal conditions of enzyme concentration (1.4%, w/w), temperature (44°C), time (66 min) and irradiation power (419W). Moreover, there were no significant variations in physicochemical properties of MAAEE-extracted oil (MAAEEO) and Soxhlet-extracted oil (SEO), but MAAEEO exhibited better oxidation stability. Additionally, MAAEEO had a higher content of linoleic acid (57.33%) than SEO (53.72%), and it showed stronger antioxidant activities with the IC50 values 123.93 and 152.84, mg/mL, according to DPPH radical scavenging assay and β-carotene/linoleic acid bleaching test. SEM results illustrated the destruction of cell walls and membranes by MAAEE. MAAEE is, therefore, a promising and environmental-friendly technique for oil extraction in the food industry. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Fatty acid composition and mechanisms of the protective effects of myrtle berry seed aqueous extract in alcohol-induced peptic ulcer in rat.

    Jabri, Mohamed-Amine; Rtibi, Kais; Tounsi, Haifa; Hosni, Karim; Marzouki, Lamjed; Sakly, Mohsen; Sebai, Hichem

    2017-05-01

    This study aimed to investigate the antiulcer and antioxidant activities of myrtle berry seed aqueous extract (MBSAE) in a peptic ulcer model induced by ethanol in male Wistar rats. MBSAE is rich in total polyphenols, total flavonoids, and unsaturated fatty acids, particularly linoleic (18:2) and oleic (18:1) acids. MBSAE also exhibited in vitro antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC 50 = 172.1 μg/mL) and superoxide anion (IC 50 = 200.24 μg/mL) scavenging activities. In vivo, MBSAE provided dose-dependent protection against ethanol-induced gastric and duodenal macroscopic and histological alterations. Also, it inhibited secretory profile disturbances and lipid peroxidation, and preserved normal antioxidant enzyme activities and nonenzymatic antioxidant levels. More importantly, we showed that acute alcohol intoxication increased gastric and duodenal calcium, hydrogen peroxide, and free iron levels, whereas MBSAE treatment protected against intracellular mediator deregulation. In conclusion, we suggest that MBSAE has potent protective effects against alcohol-induced peptic ulcer in rat. This protection might be related in part to its antioxidant properties as well as its opposite effects on some studied intracellular mediators.

  1. Bamboo-like Composites of V2O5/Polyindole and Activated Carbon Cloth as Electrodes for All-Solid-State Flexible Asymmetric Supercapacitors.

    Zhou, Xi; Chen, Qiang; Wang, Anqi; Xu, Jian; Wu, Shishan; Shen, Jian

    2016-02-17

    A bamboo-like nanomaterial composed of V2O5/polyindole (V2O5/PIn) decorated onto the activated carbon cloth was fabricated for supercapacitors. The PIn could effectively enhance the electronic conductivity and prevent the dissolution of vanadium. And the activation of carbon cloth with functional groups is conducive to anchoring the V2O5 and improving surface area, which results in an enhancement of electrochemical performance and leads to a high specific capacitance of 535.5 F/g. Moreover, an asymmetric flexible supercapacitor based on V2O5/PIn@activate carbon cloth and reduced graphene oxide (rGO)@activate carbon cloth exhibits a high energy density (38.7 W h/kg) at a power density of 900 W/kg and good cyclic stability (capacitance retention of 91.1% after 5000 cycles). And the prepared device is shown to power the light-emitting diode bulbs efficiently.

  2. Design and Synthesis of SnO_2 Nanosheets/Nickel/Polyvinylidene Fluoride Ternary Composite as Free-standing, Flexible Electrode for Lithium Ion Batteries

    Zhang, Yan; Xiao, Qizhen; Lei, Gangtie; Li, Zhaohui; Li, Xiaojing

    2015-01-01

    In this report, we have designed a novel SnO_2 nanosheets/nickel/polyvinylidene fluoride ternary composite as anode materials for lithium ion batteries. The SnO_2 nanosheets are uniformly coated on the surface of nickel/polyvinylidene fluoride conductive fiber, as confirmed by XRD, SEM, and TEM characterizations. As an anode material for lithium ion batteries, this as-prepared ternary composite delivers a high capacity of 865.4 mAh g"−"1 at 200 mA g"−"1 after 60 cycles. Furthermore, the SnO_2 in this composite material exhibits a good capacity retention as well as rate capability. This result indicates the completely reversible reaction between Li_4_._4Sn and SnO_2, greatly improving the specific capacity of SnO_2. The ternary SnO_2/Ni/PVDF composite limits the volume expansion on lithium insertion, and buffer spaces during charge/discharge, resulting in the excellent cyclic performances.

  3. Artificial Neural Network Modeling and Genetic Algorithm Optimization for Cadmium Removal from Aqueous Solutions by Reduced Graphene Oxide-Supported Nanoscale Zero-Valent Iron (nZVI/rGO) Composites.

    Fan, Mingyi; Li, Tongjun; Hu, Jiwei; Cao, Rensheng; Wei, Xionghui; Shi, Xuedan; Ruan, Wenqian

    2017-05-17

    Reduced graphene oxide-supported nanoscale zero-valent iron (nZVI/rGO) composites were synthesized in the present study by chemical deposition method and were then characterized by various methods, such as Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The nZVI/rGO composites prepared were utilized for Cd(II) removal from aqueous solutions in batch mode at different initial Cd(II) concentrations, initial pH values, contact times, and operating temperatures. Response surface methodology (RSM) and artificial neural network hybridized with genetic algorithm (ANN-GA) were used for modeling the removal efficiency of Cd(II) and optimizing the four removal process variables. The average values of prediction errors for the RSM and ANN-GA models were 6.47% and 1.08%. Although both models were proven to be reliable in terms of predicting the removal efficiency of Cd(II), the ANN-GA model was found to be more accurate than the RSM model. In addition, experimental data were fitted to the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms. It was found that the Cd(II) adsorption was best fitted to the Langmuir isotherm. Examination on thermodynamic parameters revealed that the removal process was spontaneous and exothermic in nature. Furthermore, the pseudo-second-order model can better describe the kinetics of Cd(II) removal with a good R² value than the pseudo-first-order model.

  4. Facile Synthesis of A 3D Flower-Like Mesoporous Ni@C Composite Material for High-Energy Aqueous Asymmetric Supercapacitors.

    Liu, Song; An, Cuihua; Zang, Lei; Chang, Xiaoya; Guo, Huinan; Jiao, Lifang; Wang, Yijing

    2018-04-16

    A 3D flower-like mesoporous Ni@C composite material has been synthesized by using a facile and economical one-pot hydrothermal method. This unique 3D flower-like Ni@C composite, which exhibited a high surface area (522.4 m 2  g -1 ), consisted of highly dispersed Ni nanoparticles on mesoporous carbon flakes. The effect of calcination temperature on the electrochemical performance of the Ni@C composite was systematically investigated. The optimized material (Ni@C 700) displayed high specific capacity (1306 F g -1 at 2 A g -1 ) and excellent cycling performance (96.7 % retention after 5000 cycles). Furthermore, an asymmetric supercapacitor (ASC) that contained Ni@C 700 as cathode and mesoporous carbon (MC) as anode demonstrated high energy density (60.4 W h kg -1 at a power density of 750 W kg -1 ). © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Fabrication of a Cu{sub 2}O/Au/TiO{sub 2} composite film for efficient photocatalytic hydrogen production from aqueous solution of methanol and glucose

    Wang, Xi; Dong, Haitai; Hu, Zhe; Qi, Zhong; Li, Laisheng, E-mail: llsh@scnu.edu.cn

    2017-05-15

    Highlights: • A Cu{sub 2}O/Au/TiO{sub 2} film was synthesized successfully. • Hydrogen production of Cu{sub 2}O/Au/TiO{sub 2} film improved significantly. • The highest hydrogen production rate of the film was 125.3 mmol/h/m{sup 2}. • A Z-scheme charge transfer pathway was proposed. - Abstract: A novel Cu{sub 2}O/Au/TiO{sub 2} photocatalyst composite film was fabricated on a copper substrate for photocatalytic hydrogen production. The composite films, Cu{sub 2}O/Au/TiO{sub 2}, were stepwise synthesized by using electrochemical deposition, photodeposition, and coating methods. First, a Cu{sub 2}O film was synthesized using the electrochemical deposition method, after which Au was deposited onto the Cu{sub 2}O film through in-site photodeposition. Finally, TiO{sub 2} was coated on the surface of the Cu{sub 2}O/Au film. Its morphology and surface chemical composition was characterized by SEM, TEM, XRD and XPS. The optical characteristics (UV–Vis DRS, PL spectrum) of the films were also examined. The photocatalytic hydrogen production rate of the Cu{sub 2}O/Au/TiO{sub 2} composite film from a 20% vol. methanol solution increased to125.3 mmol/h/m{sup 2} under 300 W xenon lamp light irradiation. Compared to the TiO{sub 2} (13.5 mmol/h/m{sup 2}) film and Cu{sub 2}O/TiO{sub 2} film (83.2 mmol/h/m{sup 2}), the Cu{sub 2}O/Au/TiO{sub 2} film showed excellent photocatalytic performance for hydrogen generation. The Cu{sub 2}O/Au/TiO{sub 2} film has highly effective photocatalytic properties, which are attributed to the Z-scheme system and can not only enhance the absorption of solar light but also suppress the recombination of photogenerated electron-hole pairs. It is worth noting that by introducing Au into the interface of Cu{sub 2}O/TiO{sub 2}, the surface plasmon resonance (SPR)-induced local electric field formed at the Au site induces a Z-scheme charge transfer pathway inside the composite film (Cu{sub 2}O/Au/TiO{sub 2}), which promotes both the charge of the

  6. Flexible Electronics Research Facility

    Federal Laboratory Consortium — The Flexible Electronics Research Facility designs, synthesizes, tests, and fabricates materials and devices compatible with flexible substrates for Army information...

  7. Magnesium Oxide Embedded Nitrogen Self-Doped Biochar Composites: Fast and High-Efficiency Adsorption of Heavy Metals in an Aqueous Solution.

    Ling, Li-Li; Liu, Wu-Jun; Zhang, Shun; Jiang, Hong

    2017-09-05

    Lead (Pb) pollution in natural water bodies is an environmental concern due to toxic effects on aquatic ecosystems and human health, while adsorption is an effective approach to remove Pb from the water. Surface interactions between adsorbents and adsorbates play a dominant role in the adsorption process, and properly engineering a material's surface property is critical to the improvement of adsorption performance. In this study, the magnesium oxide (MgO) nanoparticles stabilized on the N-doped biochar (MgO@N-biochar) were synthesized by one-pot fast pyrolysis of an MgCl 2 -loaded N-enriched hydrophyte biomass as a way to increase the exchangeable ions and N-containing functional groups and facilitate the adsorption of Pb 2+ . The as-synthesized MgO@N-biochar has a high performance with Pb in an aqueous solution with a large adsorption capacity (893 mg/g), a very short equilibrium time (adsorption performance can be maintained with various environmentally relevant interferences including pH, natural organic matter, and other metal ions, suggesting that the material may be suitable for the treatment of wastewater, natural bodies of water, and even drinking water. In addition, MgO@N-biochar quickly and efficiently removed Cd 2+ and tetracycline. Multiple characterizations and comparative tests have been performed to demonstrate the surface adsorption and ion exchange contributed to partial Pb adsorption, and it can be inferred from these results that the high performance of MgO@N-biochar is mainly due to the surface coordination of Pb 2+ and C═O or O═C-O, pyridinic, pyridonic, and pyrrolic N. This work suggests that engineering surface functional groups of biochar may be crucial for the development of high performance heavy metal adsorbents.

  8. Self-assembly silicon/porous reduced graphene oxide composite film as a binder-free and flexible anode for lithium-ion batteries

    Tang, H.; Zhang, Y.J.; Xiong, Q.Q.; Cheng, J.D.; Zhang, Q.; Wang, X.L.; Gu, C.D.; Tu, J.P.

    2015-01-01

    A Si/porous reduced graphene oxide (rGO) composite film synthesized by evaporation and leavening method are developed as a high-performance anode material for lithium ion batteries. The porous structure as buffer base can effectively release the volume expansion of the silicon particles, increase the electrical conductivity and reduce the transfer resistance of Li ions. The Si/porous rGO composite film presents high specific capacity and good cycling stability (1261 mA h g −1 at 50 mA g −1 up to 70 cycles), as well as enhanced rate capability. This approach to prepare such a unique structure is a low-cost and facile route for the silicon-based anode materials

  9. Removal of UO{sup 2+}{sub 2} from aqueous solution using halloysite nanotube-Fe{sub 3}O{sub 4} composite

    He, Wenfang; Chen, Yuantao; Zhang, Wei; Hu, Chunlian; Wang, Jian; Wang, Pingping [Qinghai Normal University, Xining (China)

    2016-01-15

    Halloysite nanotubes (HNTs) were modified with Fe{sub 3}O{sub 4} to form novel magnetic HNTs-Fe{sub 3}O{sub 4} composites, and the composites were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The as-obtained results indicated that Fe{sub 3}O{sub 4} nanoparticles were successfully installed on the surface of HNTs. The adsorption of UO{sup 2+}{sub 2} on HNTs-Fe{sub 3}O{sub 4} was investigated as a function of solid content, contact time, pH, ionic strength and temperature by batch experiments. The consequences revealed that the adsorption of UO{sup 2+}{sub 2} onto HNTs-Fe{sub 3}O{sub 4} was strongly dependent on pH and ionic strength. Equilibrium data fitted well with the Langmuir isotherm. The experimental results demonstrated that the adsorbents with HNTs-Fe{sub 3}O{sub 4} had the largest adsorption capacity of 88.32mg/g for UO{sup 2+}{sub 2}.

  10. Synthesis and characterization of Poly(2-hydroxyethylmethacrylate-hydroxyapatite) a novel composite for the removal of Lead(II) from aqueous solutions

    Akkaya, Recep [Vocational School of Health Services, Cumhuriyet University, Sivas (Turkey)

    2012-11-15

    In the present study, a novel adsorbent, poly (2-hydroxyethylmethacrylate-hydroxyapatite) [P(HEMA-Hap)], was prepared and characterized. The synthesis was achieved by means of free-radical polymerization and a number of structural characterization methods, including FT-IR, XRD, TGA, SEM, BET-porosity, and swelling tests. Pb{sup 2+} adsorption was performed using a series of pH, time, and temperature ranges. The reusability of the composite was also tested. The results obtained indicated that the novel adsorbent is able to bind Pb{sup 2+} ions with strong chemical affinity. The adsorption results were fitted to the classic Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) sorption models. Thermodynamic parameters obtained demonstrated that the sorption process was spontaneous ({Delta}G < 0), endothermic ({Delta}H > 0), as expected. The process was also consistent with the pseudo-second-order model, and chemical adsorption was determined to be the rate-controlling step. It was also shown that the composite could be used for five consecutive adsorption processes. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Adsorption of Reactive Brilliant Red X-3B in Aqueous Solutions on Clay–Biochar Composites from Bagasse and Natural Attapulgite

    Si Chen

    2018-05-01

    Full Text Available The study aims to determine the adsorption mechanism of reactive brilliant red X-3B (RBR on a novel low-cost clay–biochar composite with different proportions of bagasse and natural attapulgite (ATP. Pure bagasse, pure ATP, and two mixtures with weight ratios of 1:5 and 1:3 were pyrolyzed at 700 °C for 4 h in a muffle furnace. Biochar samples were characterized with an element analyzer and by scanning electron microscopy, X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller method, and zeta potential measurement. Results of the batch and leaching experiments showed that the adsorption capacities followed the order of 1:3 clay–biochar > 1:5 clay–biochar > bagasse biochar > pure ATP. Furthermore, ATP and bagasse exerted a synergistic effect on the adsorption of RBR. The adsorption data showed good correlation with the Langmuir isotherm, and the kinetic data were fitted to the pseudo-second-order model. The adsorption of RBR on clay-biochar involved electrostatic interaction, hydrogen bond, π–π interactions, and surface participation. The modification of biochar by ATP improved the adsorption capacity by increasing functional groups and creating adsorption sites. Therefore, ATP-modified clay–biochar composites could be effective adsorbents for the removal of RBR from wastewater.

  12. Adsorption Properties of PVA/PAA/clay Composite Hydrogel Synthesized by Gamma Radiation and its Application in Removal of Crystal Violet Dye from Its Aqueous Solution

    Kamal, H.; El-Sayed, A. Hegazy; Mohamed, M.M.; Sabaa, M.W.; El-Dessouky, M.M.

    2014-01-01

    Copolymer hydrogels composed of Poly vinyl alcohol (PVA) and Poly acrylic acid (PAA) were prepared by γ-irradiation in the presence of N,N’ methylene bis acrylamide (MBAM) as crosslinking agent or bentonite clay. The copolymers were characterized by FTIR and SEM. The dye adsorption experiments for Crystal Violet dye (CV) were carried out by using bath procedure. UV-visible absorption spectroscopy was used to determine the adsorption behavior. The effect of different copolymer composition, clay concentration, ph, contact time, adsorbent dose, initial dye concentration, and adsorption temperature were investigated to obtain the best experimental conditions. The adsorption equilibrium was attained after about 24h. of contact time. It was found that the adsorption process was correlated with Freundlich isotherm equation. Kinetic and thermodynamic studies of CV dye onto the prepared hydrogels were also evaluated

  13. Chemical studies on polyaniline titanotungstate as a new composite cation exchanger and its analytical applications for removal of cesium from aqueous solutions

    Ibrahim, M.K.M.

    2012-01-01

    Polyaniline titanotungstate has been synthesized by incorporation of organic polymer polyaniline into the inorganic precipitate of titanotungstate. This material was characterized using IR, X-Ray, SEM and DTA-TGA analysis. The influences of initial concentration of metal ions, particle size and temperature have been reported. The material stability was investigated in water, acids, alkaline solutions, and at high temperature up to 850 degree C. Ion-exchange capacity and distribution coefficients (K d ) for ten metal ions have been determined. It was found that the polyaniline titanotungstate has high affinity and high selectivity for Cs + . The material has high separation for Cs + ion from other metal ions. The comparison of composite (PATiW) and inorganic material (TiW) was studied and indicated that the composite material is better than the inorganic one in selectivity of Cs + . Thermodynamic parameter of Cs + exchange process, such as changes in Gibbs free energy (δG o ), enthalpy (δH o ), and entropy (δS o ) have been calculated. It was found that numerical value of δG decrease with an increase in temperature,indicating that the sorption reaction of adsorbent was spontaneous and more favorable at higher temperature. The positive value of δH o corresponds to the endothermic nature of sorption processes and suggested that chemisorptions were the predominant mechanism. A comparison of kinetic models applied to the sorption rate data of Cs + was evaluated for the pseudo first-order, pseudo second-order, homogeneous particle diffusion, shell model and intraparticle diffusion models. The results showed that Cs + is sorption onto PATiW and TiW with particle diffusion mechanism. Self diffusion coefficient (D i ), Activation energy (Ea) and entropy (δS * ) of activation were also computed from thelinearized form of Arrhenius equation. Column studies in acid and alkaline solutions were studied. A kinetic study for removal cesium from milk was investigated.

  14. Explosive compositions

    1971-04-01

    An explosive composition containing ammonium nitrate consists of (1) from 40 to 75 Pt. by wt of particulate ammonium nitrate, (2) from 20 to 35 Pt. by wt of a solution selected from the group consisting of aqueous magnesium nitrate, aqueous ammonium nitrate and aqueous ammoniacal ammonium nitrate; and (3) at least 2 Pt. by wt of a setting agent selected from the group consisting of alkaline earth metal oxides, zinc oxide, lead monoxide, calcined dolomitic limestone, anhydrous calcium sulfate, anhydrous magnesium sulfate, anhydrous sodium tetrapyrophosphate and anhydrous sodium thiosulfate. The setting agent is further characterized in setting the composition to a solid material which contains solvent used in the liquid phase. (Abstract only - original article not available from T.U.)

  15. Explosive composition

    Slykhouse, T E

    1968-05-09

    An ammonium nitrate explosive composition is characterized in that it contains from 40 to 75 parts by wt of particulate ammonium nitrate, from 20 to 35 parts by wt of a solution selected from the group consisting of aqueous magnesium nitrate, aqueous ammonium nitrate, and aqueous ammoniacal ammonium nitrate. It also contains at least 2 parts by wt of a setting agent selected from the group consisting of alkaline earth metal oxides, zinc oxide, lead monoxide, calcined dolomitic limestone, substantially anhydrous calcium sulfate, substantially anhydrous magnesium sulfate, substantially anhydrous sodium tetrapyrophosphate and substantially anhydrous sodium thiosulfate. The setting agent is further characterized in that it sets the composition to a solid material which contains solvent used in the liquid phase. (12 claims)

  16. Flexible Temperature Sensors on Fibers

    Marcin Sloma

    2010-08-01

    Full Text Available The aim of this paper is to present research dedicated to the elaboration of novel, miniaturized flexible temperature sensors for textronic applications. Examined sensors were manufactured on a single yarn, which ensures their high flexibility and good compatibility with textiles. Stable and linear characteristics were obtained by special technological process and applied temperature profiles. As a thermo-sensitive materials the innovative polymer compositions filled with multiwalled carbon nanotubes were used. Elaborated material was adapted to printing and dip-coating techniques to produce NTC composites. Nanotube sensors were free from tensometric effect typical for other carbon-polymer sensor, and demonstrated TCR of 0.13%/K. Obtained temperature sensors, compatible with textile structure, can be applied in rapidly developing smart textiles and be used for health and protections purposes.

  17. Balance and flexibility.

    2003-12-01

    The 'work-life balance' and flexible working are currently key buzz terms in the NHS. Those looking for more information on these topics should visit Flexibility at www.flexibility.co.uk for a host of resources designed to support new ways of working, including information on flexible workers and flexible rostering, the legal balancing act for work-life balance and home working.

  18. Artificial Neural Network Modeling and Genetic Algorithm Optimization for Cadmium Removal from Aqueous Solutions by Reduced Graphene Oxide-Supported Nanoscale Zero-Valent Iron (nZVI/rGO Composites

    Mingyi Fan

    2017-05-01

    Full Text Available Reduced graphene oxide-supported nanoscale zero-valent iron (nZVI/rGO composites were synthesized in the present study by chemical deposition method and were then characterized by various methods, such as Fourier-transform infrared spectroscopy (FTIR and X-ray photoelectron spectroscopy (XPS. The nZVI/rGO composites prepared were utilized for Cd(II removal from aqueous solutions in batch mode at different initial Cd(II concentrations, initial pH values, contact times, and operating temperatures. Response surface methodology (RSM and artificial neural network hybridized with genetic algorithm (ANN-GA were used for modeling the removal efficiency of Cd(II and optimizing the four removal process variables. The average values of prediction errors for the RSM and ANN-GA models were 6.47% and 1.08%. Although both models were proven to be reliable in terms of predicting the removal efficiency of Cd(II, the ANN-GA model was found to be more accurate than the RSM model. In addition, experimental data were fitted to the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R isotherms. It was found that the Cd(II adsorption was best fitted to the Langmuir isotherm. Examination on thermodynamic parameters revealed that the removal process was spontaneous and exothermic in nature. Furthermore, the pseudo-second-order model can better describe the kinetics of Cd(II removal with a good R2 value than the pseudo-first-order model.

  19. Evaluation of silica/ferrocyanide composite as a dual-function material for simultaneous removal of ¹³⁷Cs⁺ and ⁹⁹TcO₄⁻ from aqueous solutions.

    Mahmoud, Mamdoh R; Seliman, Ayman F

    2014-09-01

    A novel mesoporous silica-coated ferrocyanide (MSCFC) composite was successfully synthesized and evaluated as a dual-function material for simultaneous removal of (137)Cs(+) cations and (99)TcO4(-) anions from aqueous solutions. Sorption behavior of both radionuclides on MSCFC under different experimental conditions has been studied using a batch technique. Results revealed that about 100% of (137)Cs(+) and 97% of (99)TcO4(-) were removed by MSCFC in the pH ranges of 2.2-12.4 and 4.1-9.5, respectively. Sorption kinetic data were analyzed by pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models, while Langmuir and Freundlich models were applied for the sorption isotherms. The maximum sorption capacity of MSCFC for radiocesium was determined and compared with other reported sorbents. Applicability of the coated ferrocyanide for simultaneous removal of (137)Cs(+) and (99)TcO4(-) from low-level liquid radioactive waste (LLLW) was also tested, and the data revealed that 99.91% and 98.34% were removed from (137)Cs(+) and (99)TcO4(-), respectively. It is concluded that MSCFC exhibits excellent efficiency for simultaneous removal of the mixed radionuclides with different charge from LLLW. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Advanced oxidation of biorefractory organics in aqueous solution together with bioelectricity generation by microbial fuel cells with composite FO/GPEs

    Fu, Bao-rong; Shen, Chao; Ren, Jing; Chen, Jia-yi; Zhao, Lin

    2018-03-01

    In this study, ferric oxide loading graphite particle electrodes (FO/GPEs) were prepared as cathode of a three-dimensional electrode MFC-Fenton system. The properties of the composite cathode were examined with higher surface area and more mesopores. FO/GPEs could work as both cathode and Fenton iron reagents, contributing to high oxidation activity and better performance of electricity generation. The application of FO/GPEs MFC-Fenton system on degrading p-nitrophenol presented high catalytic efficiency in a wide range of pH value. The removal of p-nitrophenol and TOC attained to about 85 % within 8 and 64 h at neutral pH, respectively. A neutral FO/GPEs MFC-Fenton oxidation mechanism was also proposed. Specifically, both the surface iron sites and dissolved iron ions catalyzed the decomposition of H2O2. As results, the generated hydroxyl radicals were used for p-nitrophenol degradation and the iron oxide was recycled.

  1. Self-propagating synthesis and aqueous durability of Nd-bearing zirconolite-rich composites using Ca(NO{sub 3}){sub 2} as the oxidant

    Zhang, Kuibao, E-mail: xiaobao320@163.com [State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials, Southwest University of Science and Technology, Mianyang, Sichuan 621010 (China); National Defense Key Discipline Lab of Nuclear Waste and Environmental Safety, Southwest University of Science and Technology, Mianyang 621010 (China); He, Shihong [State Nuclear Power Research Institute, Beijing 100029 (China); Yin, Dan; Peng, Le; Wu, Jingjun [State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials, Southwest University of Science and Technology, Mianyang, Sichuan 621010 (China)

    2016-09-15

    Synroc is recognized as the second-generation waste form for safety disposal of high-level radioactive waste (HLW). In this study, zirconolite-rich Synroc waste form was readily synthesized by self-propagating high-temperature plus quick pressing (SHS/QP) using Ca(NO{sub 3}){sub 2} as the oxidant and Ti as the reductant. As the surrogate of trivalent actinides, Nd{sub 2}O{sub 3} was introduced to equally substitute the Ca and Zr sites of zirconolite with nominal stoichiometry of Ca{sub 1−x}Zr{sub 1−x}Nd{sub 2x}Ti{sub 2}O{sub 7}. The results demonstrate that zirconolite, perovskite and pyrochlore (Ca{sub 2}Ti{sub 2}O{sub 6}) coexist as the ceramic components after SHS reaction. The introduction of Nd{sub 2}O{sub 3} promotes the formation of perovskite. Nd is mostly incorporated into the Ca sites of these phases. The normalized elemental leaching rates of Ca and Nd are fairly constant in low values of 1.80 × 10{sup −2} g m{sup −2} d{sup −1} and 6.12 × 10{sup −4} g m{sup −2} d{sup −1} after 42 days. - Highlights: • Zirconolite-rich composite was synthesized by SHS using Ca(NO{sub 3}){sub 2} as the oxidant. • Nd{sub 2}O{sub 3} was successfully immobilized into the crystal structure of this waste form. • Nd was mostly incorporated into the Ca sites of zirconolite, perovskite and pyrochlore. • The normalized leaching rates of Ca and Nd are in relatively low values.

  2. Optimization of Nb{sub 2}O{sub 5}/Ag/Nb{sub 2}O{sub 5} multilayers as transparent composite electrode on flexible substrate with high figure of merit

    Dhar, Aritra [Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287 (United States); Alford, T. L. [School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States)

    2012-11-15

    Different multilayer structures of Nb{sub 2}O{sub 5}/Ag/Nb{sub 2}O{sub 5} have been deposited onto flexible substrates by sputtering at room temperature to develop an indium free transparent composite electrode. The effect of Ag thickness on the electrical and optical properties of the multilayer stack has been studied in accordance with the Ag morphology. The critical thickness of Ag to form a continuous conducting layer is found to be 9.5 nm. A new conduction mechanism has been proposed to describe the conduction before and after the critical thickness. The effective Hall resistivity of the optimized films is as low as 6.44 Multiplication-Sign 10{sup -5} Ohm-Sign -cm with a carrier concentration and mobility of 7.4 Multiplication-Sign 10{sup 21} cm{sup -3} and 13.1 cm{sup 2} /V-s, respectively, at the critical Ag layer thickness. The multilayer stack has been optimized to obtain a sheet resistance of 7.2 Ohm-Sign /sq and an average optical transmittance of 86% at 550 nm without any substrate heating or post-annealing process. The Haacke figure of merit (FOM) has been calculated for the films, and the multilayer with a 9.5 nm thick Ag layer has the highest FOM at 31.5 Multiplication-Sign 10-3 {Omega}{sup -1}, which is one of the highest FOM values reported for TCE deposited at room temperature on a flexible substrate.

  3. Larvicidal effects of aqueous extracts of Balanites aegyptiaca (desert ...

    Administrator

    The effect of aqueous extracts of the fruit pulp, seed kernel, roots, bark, and leaves of Balanites aegyptiaca Del. ... Mosquitoes constitute a major public health menace as ..... chemical characteristics, oil recovery and fatty acid composition of.

  4. Flexible magnetoimpedance sensor

    Li, Bodong; Kavaldzhiev, Mincho; Kosel, Jü rgen

    2015-01-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors's magnetic field and frequency

  5. Flexible Carpooling: Exploratory Study

    Dorinson, Diana; Gay, Deanna; Minett, Paul; Shaheen, Susan

    2009-01-01

    Energy consumption could be reduced if more people shared rides rather than driving alone yet carpooling represents a small proportion of all potential carpoolers. Prior research has found that many who might carpool were concerned about reduced flexibility with carpooling. If flexibility is one of the barriers how could carpooling be organized to be more flexible? In Northern Virginia a flexible system has evolved where there are 3,500 single-use carpools per day. In another example there ...

  6. MIPs in Aqueous Environments.

    Wan, Ying-chun; Ma, Hui-ting; Lu, Bin

    2015-01-01

    When organic solvent-compatible molecularly imprinted polymers (MIPs) are used in aqueous environment, how to reduce nonspecific binding is a major challenge. By modifying the binding solvents and introducing appropriate washing and elution steps, even relatively hydrophobic MIPs can gain optimal rebinding selectivity in aqueous conditions. Furthermore, water-compatible MIPs that can be used to treat aqueous samples directly have been prepared. The use of hydrophilic co-monomers, the controlled surface modification through controlled radical polymerization, and the new interfacial molecular imprinting methods are different strategies to prepare water-compatible MIPs. By combining MIPs with other techniques, both organic solvent-compatible and water-compatible MIPs can display better functional performances in aqueous conditions. Intensive studies on MIPs in aqueous conditions can provide new MIPs with much-improved compatibilities that will lead to more interesting applications in biomedicine and biotechnology.

  7. Chemical composition of Clinopodium menthifolium aqueous extract

    Analysis by HPLC confirmed the presence of gallic acid, caffeic acid and .... The total flavonoids were estimated according to the method described by Markham .... centrifugation, supernatants were used for protein quantification and enzyme ...

  8. Direct Synthesis of MnO2 Nanorods on Carbon Cloth as Flexible Supercapacitor Electrode

    Shuang Xi

    2017-01-01

    Full Text Available MnO2 nanorod/carbon cloth (MnO2/CC composites were prepared through in situ redox deposition as freestanding electrodes for flexible supercapacitors. The CC substrates possessing porous and interconnecting structures enable the uniform decoration of MnO2 nanorods on each fiber, thus forming conformal coaxial micro/nanocomposites. Three-dimensional CC can provide considerable specific surface area for high mass loading of MnO2, and the direct deposition process without using polymeric binders enables reliable electrical connection of MnO2 with CC. The effect of MnO2 decoration on the electrochemical performances was further investigated, indicating that the electrode prepared with 40 min deposition time shows high specific capacitance (220 F/g at a scan rate of 5 mV/s and good cycling property (90% of the initial specific capacitance was maintained after 2500 cycles in 1 M Na2SO4 aqueous solution. This enhanced electrochemical performance is ascribed to the synergistic effect of good conductivity of carbon substrates as well as outstanding pseudocapacitance of MnO2 nanorods. The obtained MnO2/CC compositing electrode with the advantages of low cost and easy fabrication is promising in applications of flexible supercapacitors.

  9. Aqueous lithium air batteries

    Visco, Steven J.; Nimon, Yevgeniy S.; De Jonghe, Lutgard C.; Petrov, Alexei; Goncharenko, Nikolay

    2017-05-23

    Aqueous Li/Air secondary battery cells are configurable to achieve high energy density and prolonged cycle life. The cells include a protected a lithium metal or alloy anode and an aqueous catholyte in a cathode compartment. The aqueous catholyte comprises an evaporative-loss resistant and/or polyprotic active compound or active agent that partakes in the discharge reaction and effectuates cathode capacity for discharge in the acidic region. This leads to improved performance including one or more of increased specific energy, improved stability on open circuit, and prolonged cycle life, as well as various methods, including a method of operating an aqueous Li/Air cell to simultaneously achieve improved energy density and prolonged cycle life.

  10. Office flexible cystoscopy.

    Kavoussi, L R; Clayman, R V

    1988-11-01

    Since the development of the first purpose-built flexible cystoscope in 1984, flexible cystoscopy has become an accepted diagnostic and therapeutic modality. Indeed, it is estimated that more than 10 per cent of practicing urologists are already familiar with this technology. The flexible cystoscope has markedly extended the urologist's ability to examine the bladder, and it has become a valuable adjunct to the rigid cystoscope. Although the operation of this instrument is vastly different from that of its rigid counterpart, with practice, the technique can be learned. After experience is obtained with diagnostic flexible cystoscopy, the urologist will likely prefer this new instrument for bladder inspection, as it provides for a more thorough yet less morbid and less expensive examination. In the future, the development of improved and smaller instrumentation will further extend the therapeutic indications for flexible cystoscopy. Indeed, advances in laser technology are already providing the urologist with 300- to 600-micron (0.9 to 1.8F) flexible probes capable of incision (KTP laser), fulguration (Nd:YAG laser), and stone disintegration (tunable dye laser). Lastly, the skills obtained in using the flexible cystoscope are all readily applicable to the development of dexterity with the already available flexible nephroscope and the more recently developed flexible ureteroscope.

  11. Chemical composition of Clinopodium menthifolium aqueous extract and its influence on antioxidant system in black nightshade (Solanum nigrum and pepper (Capsicum annuum seedlings and mortality rate of whitefly (Trialeurodes vaporariorum adults

    J. Šućur

    2017-11-01

    Full Text Available The use of allelochemicals as weed control agents is becoming widely investigated. However, the impact of these bioherbicides on cultivated plants is less known. This study was carried out in order to evaluate the allelopathic effects of the aqueous extract of Clinopodium menthifolium on black nightshade (Solanum nigrum antioxidant properties to explore the potential of this species in weed control and on pepper (Capsicum annuum antioxidant properties so as to assess its possible side effects when applied as bioherbicide in organic production. Taking into account that plant extracts should be an alternative source for insect control, additional aim was also to evaluate contact effect of C. menthifolium aqueous extract against the greenhouse whitefly (Trialeurodes vaporariorum. Analysis by HPLC confirmed the presence of gallic acid, caffeic acid and 2-hidroxy-cinnamic acid as major components in the C. menthifolium aqueous extract. Both tested concentrations of C. menthifolium aqueous extract induced lipid peroxidation in black nightshade leaves and roots. It was observed that the aqueous extract with a concentration of 0.1% showed a toxic effect with 50% mortality of greenhouse whitefly adults.

  12. Organizational flexibility estimation

    Komarynets, Sofia

    2013-01-01

    By the help of parametric estimation the evaluation scale of organizational flexibility and its parameters was formed. Definite degrees of organizational flexibility and its parameters for the Lviv region enterprises were determined. Grouping of the enterprises under the existing scale was carried out. Special recommendations to correct the enterprises behaviour were given.

  13. Reversibly Bistable Flexible Electronics

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  14. Flexible magnetoimpidence sensor

    Kavaldzhiev, Mincho

    2015-05-01

    Recently, flexible electronic devices have attracted increasing interest, due to the opportunities they promise for new applications such as wearable devices, where the components are required to flex during normal use[1]. In this light, different magnetic sensors, like microcoil, spin valve, giant magnetoresistance (GMR), magnetoimpedance (MI), have been studied previously on flexible substrates.

  15. Flexibility within Fidelity

    Kendall, Philip C.; Gosch, Elizabeth; Furr, Jami M.; Sood, Erica

    2008-01-01

    The authors address concerns regarding manual-based treatments, highlighting the role of flexibility and creativity. A cognitive-behavioral therapy for youth anxiety called the Coping Cat program demonstrates the flexible application of manuals and emphasizes the importance of a child-centered, personalized approach that involves the child in the…

  16. Flexible position probe assembly

    Schmitz, J.J.

    1977-01-01

    The combination of a plurality of tubular transducer sections and a flexible supporting member extending through the tubular transducer sections forms a flexible elongated probe of a design suitable for monitoring the level of an element, such as a nuclear magnetically permeable control rod or liquid. 3 claims, 23 figures

  17. Aerogel / Polymer Composite Materials

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2017-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  18. Flexible Carbon Aerogels

    Marina Schwan

    2016-09-01

    Full Text Available Carbon aerogels are highly porous materials with a large inner surface area. Due to their high electrical conductivity they are excellent electrode materials in supercapacitors. Their brittleness, however, imposes certain limitations in terms of applicability. In that context, novel carbon aerogels with varying degree of flexibility have been developed. These highly porous, light aerogels are characterized by a high surface area and possess pore structures in the micrometer range, allowing for a reversible deformation of the aerogel network. A high ratio of pore size to particle size was found to be crucial for high flexibility. For dynamic microstructural analysis, compression tests were performed in-situ within a scanning electron microscope allowing us to directly visualize the microstructural flexibility of an aerogel. The flexible carbon aerogels were found to withstand between 15% and 30% of uniaxial compression in a reversible fashion. These findings might stimulate further research and new application fields directed towards flexible supercapacitors and batteries.

  19. Global Sourcing Flexibility

    Ørberg Jensen, Peter D.; Petersen, Bent

    2013-01-01

    the higher costs (but decreased risk for value chain disruption) embedded in a more flexible global sourcing model that allows the firm to replicate and/or relocate activities across multiple locations. We develop a model and propositions on facilitating and constraining conditions of global sourcing...... sourcing flexibility. Here we draw on prior research in the fields of organizational flexibility, international business and global sourcing as well as case examples and secondary studies. In the second part of the paper, we discuss the implications of global sourcing flexibility for firm strategy...... and operations against the backdrop of the theory-based definition of the construct. We discuss in particular the importance of global sourcing flexibility for operational performance stability, and the trade-off between specialization benefits, emerging from location and service provider specialization, versus...

  20. Fabrication of flexible conductive films derived from poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonic acid) (PEDOT:PSS) on the nonwoven fabrics substrate

    Wu, Chieh-Han; Shen, Hsiu-Ping; Don, Trong-Ming; Chiu, Wen-Yen

    2013-01-01

    In this research, conducting poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonic acid) (PEDOT:PSS) aqueous dispersion was synthesized at first via chemical oxidative polymerization and followed by mixing it with poly(styrene-r-butyl acrylate) P(St-BA) aqueous latex, creating a conductive material with outstanding stretchability. The elastic conductive composite were then film formed on the glass and poly(ethylene terephthalate) (PET) nonwoven fabric substrate by spin coating and dip coating, respectively. Composite films with various contents of PEDOT:PSS polymer (10–100 wt.%) had been prepared. From the conductivity measurements, the conductivity was still kept as high as 88 S cm −1 even the PEDOT:PSS content was lowered to 10 wt.%. Furthermore, the elasticity of conductive films on the PET-nonwoven fabric substrate was evaluated by the 180° bending test repeating 100 times. With introducing soft P(St-BA) material in the PEDOT:PSS phase, the surface resistance increased merely 3–6 times after bending 100 times, while the surface resistance for pure PEDOT:PSS film could reach 18–20 times. - Highlights: • Flexible PEDOT:PSS based material had been coated on the PET-nonwoven fabrics. • The integrity of conductive circuit on fabrics was evaluated by bending test. • With adding rubbery material, the flexibility of PEDOT:PSS coating was enhanced

  1. Fabrication of flexible conductive films derived from poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonic acid) (PEDOT:PSS) on the nonwoven fabrics substrate

    Wu, Chieh-Han [Institute of Polymer Science and Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Shen, Hsiu-Ping [Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Don, Trong-Ming, E-mail: tmdon@mail.tku.edu.tw [Department of Chemical and Materials Engineering, Tamkang University, New Taipei 251, Taiwan, ROC (China); Chiu, Wen-Yen, E-mail: ycchiu@ntu.edu.tw [Institute of Polymer Science and Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China)

    2013-12-16

    In this research, conducting poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonic acid) (PEDOT:PSS) aqueous dispersion was synthesized at first via chemical oxidative polymerization and followed by mixing it with poly(styrene-r-butyl acrylate) P(St-BA) aqueous latex, creating a conductive material with outstanding stretchability. The elastic conductive composite were then film formed on the glass and poly(ethylene terephthalate) (PET) nonwoven fabric substrate by spin coating and dip coating, respectively. Composite films with various contents of PEDOT:PSS polymer (10–100 wt.%) had been prepared. From the conductivity measurements, the conductivity was still kept as high as 88 S cm{sup −1} even the PEDOT:PSS content was lowered to 10 wt.%. Furthermore, the elasticity of conductive films on the PET-nonwoven fabric substrate was evaluated by the 180° bending test repeating 100 times. With introducing soft P(St-BA) material in the PEDOT:PSS phase, the surface resistance increased merely 3–6 times after bending 100 times, while the surface resistance for pure PEDOT:PSS film could reach 18–20 times. - Highlights: • Flexible PEDOT:PSS based material had been coated on the PET-nonwoven fabrics. • The integrity of conductive circuit on fabrics was evaluated by bending test. • With adding rubbery material, the flexibility of PEDOT:PSS coating was enhanced.

  2. Radiolabelled sucralfate compositions

    Vasquez, T.E.; Bridges, R.L.; Braunstein, P.; Jansholt, A.

    1984-01-01

    A novel radiopharmaceutical composition comprising an aqueous solution or suspension containing a radiolabelled sucralfate or sucralfate derivative or precursor is claimed. The composition is effective for in vivo scintigraphic imaging of the gastrointestinal muscosal areas in humans. The sucralfate is combined with a radiolabelled albumin or other protein or protein derivative under acidic conditions

  3. Cell voltage versus electrode potential range in aqueous supercapacitors

    Dai, Zengxin; Peng, Chuang; Chae, Jung Hoon; Ng, Kok Chiang; Chen, George Z.

    2015-01-01

    Supercapacitors with aqueous electrolytes and nanostructured composite electrodes are attractive because of their high charging-discharging speed, long cycle life, low environmental impact and wide commercial affordability. However, the energy capacity of aqueous supercapacitors is limited by the electrochemical window of water. In this paper, a recently reported engineering strategy is further developed and demonstrated to correlate the maximum charging voltage of a supercapacitor with the c...

  4. Characterization of fatty acid and triacylglycerol composition in animal fats using silver-ion and non-aqueous reversed-phase high-performance liquid chromatography/mass spectrometry and gas chromatography/flame ionization detection

    Lísa, M.; Netušilová, K.; Franěk, L.; Dvořáková, H.; Vrkoslav, Vladimír; Holčapek, M.

    2011-01-01

    Roč. 1218, č. 42 (2011), s. 7499-7510 ISSN 0021-9673 R&D Projects: GA ČR GA203/09/0139 Institutional research plan: CEZ:AV0Z40550506 Keywords : silver-ion HPLC * non-aqueous reversed-phase HPLC * triacylglycerol Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 4.531, year: 2011

  5. Microstructural characterization of copper corrosion in aqueous and soil environments

    Srivastava, A.; Balasubramaniam, R.

    2005-01-01

    Scanning electron microscopy has been used to investigate the surface films on pure copper after exposure to different aqueous and soil environments, containing chloride, sulfide and ammonium salts. The morphology of the films formed on copper surface in aqueous and soil environments was different for the same amount of pollutants. The surface films formed in soil environments were not homogenous in contrast to the films formed in aqueous environments. The damaging effect of chloride ions and the benign role of sulfide ions were revealed in both the environments. Local compositional analysis confirmed that the surface films formed on copper consisted predominantly of copper and oxygen

  6. Flexible Word Classes

    • First major publication on the phenomenon • Offers cross-linguistic, descriptive, and diverse theoretical approaches • Includes analysis of data from different language families and from lesser studied languages This book is the first major cross-linguistic study of 'flexible words', i.e. words...... that cannot be classified in terms of the traditional lexical categories Verb, Noun, Adjective or Adverb. Flexible words can - without special morphosyntactic marking - serve in functions for which other languages must employ members of two or more of the four traditional, 'specialised' word classes. Thus......, flexible words are underspecified for communicative functions like 'predicating' (verbal function), 'referring' (nominal function) or 'modifying' (a function typically associated with adjectives and e.g. manner adverbs). Even though linguists have been aware of flexible world classes for more than...

  7. Reversibly Bistable Flexible Electronics

    Alfaraj, Nasir

    2015-01-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent

  8. Flexibility in insulin prescription

    Sanjay Kalra

    2016-01-01

    Full Text Available This communication explores the concept of flexibility, a propos insulin preparations and insulin regimes used in the management of type 2 diabetes. The flexibility of an insulin regime or preparation is defined as their ability to be injected at variable times, with variable injection-meal time gaps, in a dose frequency and quantum determined by shared decision making, with a minimal requirement of glucose monitoring and health professional consultation, with no compromise on safety, efficiency and tolerability. The relative flexibility of various basal, prandial and dual action insulins, as well as intensive regimes, is compared. The biopsychosocial model of health is used to assess the utility of different insulins while encouraging a philosophy of flexible insulin usage.

  9. REE and Y in groundwater in the upper 1.2 km of Proterozoic granitoids (Eastern Sweden) - Assessing the role of composition and origin of groundwaters, geochemistry of fractures, and organic/inorganic aqueous complexation

    Mathurin, Frédéric A.; Åström, Mats E.; Drake, Henrik; Maskenskaya, Olga M.; Kalinowski, Birgitta E.

    2014-11-01

    Yttrium and rare earth elements (YREEs) are studied in groundwater in the shallow regolith aquifer and the fracture networks of the upper 1.2 km of Paleoproterozoic granitoids in boreal Europe (Laxemar and Forsmark areas, Sweden). The study includes groundwater sampled via a total of 34 shallow boreholes reaching the bottom of the regolith aquifer, and 72 deep boreholes with equipment designed for retrieval of representative groundwater at controlled depths in the fractured bedrock. The groundwater composition differs substantially between regolith and fracture groundwater and between areas, which affects the dissolved YREE features, including concentrations and NASC normalized patterns. In the fresh groundwater in the regolith aquifers, highest YREE concentrations occur (10th and 90th percentile; Laxemar: 4.4-82 μg L-1; Forsmark: 1.9-19 μg L-1), especially in the slightly acidic groundwater (pH: 6.3-7.2 - Laxemar), where the normalized YREE patterns are slightly enriched in light REEs (LaNASC/YNASC: 1.1-2.4). In the recharge areas, where redox potentials of the regolith groundwater is more moderate, negative Ce anomaly (Laxemar: 0.37-0.45; Forsmark: 0.15-0.92) and positive Y anomaly (mainly in Forsmark: 1.0-1.7) are systematically more pronounced than in discharge areas. The significant correlations between the YREE features and dissolved organic carbon, minor elements, and somewhat pH suggest a strong control of humic substances (HSs) together with Al rich colloids and redox sensitive Fe-Mn hydrous precipitates on the dissolved YREE pools. In the bedrock fractures, the groundwater is circumneutral to slightly basic and displays YREE concentrations that are at least one order of magnitude lower than the regolith groundwater, and commonly below detection limit in the deep brackish and saline groundwater, with some exceptions such as La and Y. At intermediate depth (>50 m), where groundwater of meteoric origin percolates, the LaNASC/YNASC values moderately to

  10. Flexible displays, rigid designs?

    Hornbæk, Kasper

    2015-01-01

    Rapid technological progress has enabled a wide range of flexible displays for computing devices, but the user experience--which we're only beginning to understand--will be the key driver for successful designs.......Rapid technological progress has enabled a wide range of flexible displays for computing devices, but the user experience--which we're only beginning to understand--will be the key driver for successful designs....

  11. Aqueous polyethylene oxide solutions

    Breen, J.

    1987-01-01

    A number of aspects concerning the reorientation of polymer, water and ion hydration complexes have been studied in aqueous solution of polyethylene oxide (PEO). The polymer dynamics are investigated by 1 H-PEO and 13 C-PEO nuclear relaxation experiments. 162 refs.; 30 figs.; 19 tabs

  12. Flexible energy-storage devices: design consideration and recent progress.

    Wang, Xianfu; Lu, Xihong; Liu, Bin; Chen, Di; Tong, Yexiang; Shen, Guozhen

    2014-07-23

    Flexible energy-storage devices are attracting increasing attention as they show unique promising advantages, such as flexibility, shape diversity, light weight, and so on; these properties enable applications in portable, flexible, and even wearable electronic devices, including soft electronic products, roll-up displays, and wearable devices. Consequently, considerable effort has been made in recent years to fulfill the requirements of future flexible energy-storage devices, and much progress has been witnessed. This review describes the most recent advances in flexible energy-storage devices, including flexible lithium-ion batteries and flexible supercapacitors. The latest successful examples in flexible lithium-ion batteries and their technological innovations and challenges are reviewed first. This is followed by a detailed overview of the recent progress in flexible supercapacitors based on carbon materials and a number of composites and flexible micro-supercapacitors. Some of the latest achievements regarding interesting integrated energy-storage systems are also reviewed. Further research direction is also proposed to surpass existing technological bottle-necks and realize idealized flexible energy-storage devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Progress in aqueous rechargeable batteries

    Jilei Liu; Chaohe Xu; Zhen Chen; Shibing Ni; Ze Xiang Shen

    2018-01-01

    Over the past decades, a series of aqueous rechargeable batteries (ARBs) were explored, investigated and demonstrated. Among them, aqueous rechargeable alkali-metal ion (Li+, Na+, K+) batteries, aqueous rechargeable-metal ion (Zn2+, Mg2+, Ca2+, Al3+) batteries and aqueous rechargeable hybrid batteries are standing out due to peculiar properties. In this review, we focus on the fundamental basics of these batteries, and discuss the scientific and/or technological achievements and challenges. B...

  14. Flexible transparent electrode

    Demiryont, Hulya; Shannon, Kenneth C., III; Moorehead, David; Bratcher, Matthew

    2011-06-01

    This paper presents the properties of the EclipseTECTM transparent conductor. EclipseTECTM is a room temperature deposited nanostructured thin film coating system comprised of metal-oxide semiconductor elements. The system possesses metal-like conductivity and glass-like transparency in the visible region. These highly conductive TEC films exhibit high shielding efficiency (35dB at 1 to 100GHz). EclipseTECTM can be deposited on rigid or flexible substrates. For example, EclipseTECTM deposited on polyethylene terephthalate (PET) is extremely flexible that can be rolled around a 9mm diameter cylinder with little or no reduction in electrical conductivity and that can assume pre-extension states after an applied stress is relieved. The TEC is colorless and has been tailored to have high visible transmittance which matches the eye sensitivity curve and allows the viewing of true background colors through the coating. EclipseTECTM is flexible, durable and can be tailored at the interface for applications such as electron- or hole-injecting OLED electrodes as well as electrodes in flexible displays. Tunable work function and optical design flexibility also make EclipseTECTM well-suited as a candidate for grid electrode replacement in next-generation photovoltaic cells.

  15. Education for Flexible Personality

    Bogomir Novak

    1998-12-01

    Full Text Available Flexible personality transforms both cultural environment and itself. Post-modern personality is both contemplative and active. On one hand, it is subject to inner imagination of a creative act, and on the other hand, to creation of a tangible product What is more, flexible personality is also autonomous, mature, healthy and well balanced, as well as stable and responsive to the demand for change. Due to ever quicker changes, flexible personality is a must. And it is a task. The impact of professional work of adults on the education of children, however, is being conditioned by the exrigid family and rigid enterprises or institutions in which adults are employed. Nevertheless, flexible educational style is not repressive, as it used to be, nor permissive and totally concentrated on the child. It is a choice between the two qualities. The educators' style is dependent on their attitude towards life (play and self-education and not only towards work. Nowadays, flexibility is a way towards quality management of social and personal changes.

  16. Flexible Foam Model.

    Neilsen, Michael K.; Lu, Wei-Yang; Werner, Brian T.; Scherzinger, William M.; Lo, Chi S.

    2018-03-01

    Experiments were performed to characterize the mechanical response of a 15 pcf flexible polyurethane foam to large deformation at different strain rates and temperatures. Results from these experiments indicated that at room temperature, flexible polyurethane foams exhibit significant nonlinear elastic deformation and nearly return to their original undeformed shape when unloaded. However, when these foams are cooled to temperatures below their glass transition temperature of approximately -35 o C, they behave like rigid polyurethane foams and exhibit significant permanent deformation when compressed. Thus, a new model which captures this dramatic change in behavior with temperature was developed and implemented into SIERRA with the name Flex_Foam to describe the mechanical response of both flexible and rigid foams to large deformation at a variety of temperatures and strain rates. This report includes a description of recent experiments. Next, development of the Flex Foam model for flexible polyurethane and other flexible foams is described. Selection of material parameters are discussed and finite element simulations with the new Flex Foam model are compared with experimental results to show behavior that can be captured with this new model.

  17. Tunable aqueous virtual micropore.

    Park, Jae Hyun; Guan, Weihua; Reed, Mark A; Krstić, Predrag S

    2012-03-26

    A charged microparticle can be trapped in an aqueous environment by forming a narrow virtual pore--a cylindrical space region in which the particle motion in the radial direction is limited by forces emerging from dynamical interactions of the particle charge and dipole moment with an external radiofrequency quadrupole electric field. If the particle satisfies the trap stability criteria, its mean motion is reduced exponentially with time due to the viscosity of the aqueous environment; thereafter the long-time motion of particle is subject only to random, Brownian fluctuations, whose magnitude, influenced by the electrophoretic and dielectrophoretic effects and added to the particle size, determines the radius of the virtual pore, which is demonstrated by comparison of computer simulations and experiment. The measured size of the virtual nanopore could be utilized to estimate the charge of a trapped micro-object. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Aqueous liquid redox desulfurisation

    Reicher, M.; Niemiec, B.; Katona, T.

    1999-12-01

    The LO-CAT II process is an aqueous liquid redox process which uses ferric and ferrous iron catalysts to oxidise hydrogen sulfide (from sour gas) to elemental sulfur: the relevant chemical equations are given. Chelating agents keep the iron in solution. The system is described under the headings of (i) LO-CAT chemistry, (ii) design parameters, (iii) startup challenges, (iv) present situation and (v) anticipated future conditions. Further improvements to the system are anticipated.

  19. Chemical synthesis of composite HML / PDMcT / PAni and its application as the trhiodan adsorbent in aqueous solutions; Sintese quimica de compositos de HML/PDMcT/PAni e sua aplicacao como adsorvente do trhiodan em solucoes aquosas

    Girotto, L.G.; Pacheco, I.; Freitas, L.L. de; Oliveira, R.S.; Amaral, F.A. do; Canobre, S.C., E-mail: aylagg.eab@gmail.com [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Quimica

    2016-07-01

    The mixed hydroxide lamellar [Co -Al- Cl] was synthesize by the co- precipitation method constant pH 8. The synthesis composite HML/PDMcT/PAni was carried out via chemical. The DRX composite HML/PDMcT/PAni showed that one amorphicity in the conductor polymer doesn't hid the diffraction peaks characteristic of HML. The MEV micrographs of composite HDL / PDMcT / PAni showed a large number of crystallites compacts with several shapes characteristic to PDMcT and nanofibers of polyaniline indicating an association between the different constituents forming the composite. The results of the adsorption was 98% of the pesticide in the composite HML / PDMcT / PAni , the composite can contribute so significantly to one Thiodon withdrawal in contaminated pesticide waters. (author)

  20. Ancient aqueous environments at Endeavour crater, Mars

    Arvidson, R. E.; Squyres, S. W.; Bell, J.F.; Catalano, J.G.; Clark, B. C.; Crumpler, L.S.; de Souza, P.A.; Fairén, A.G.; Farrand, W. H.; Fox, V.K.; Gellert, Ralf; Ghosh, A.; Golombeck, M.P.; Grotzinger, J.P.; Guinness, E.A.; Herkenhoff, Kenneth E.; Jolliff, B.L.; Knoll, A.H.; Li, R.; McLennan, S.M.; Ming, D. W.; Mittlefehldt, D. W.; Moore, Johnnie N.; Morris, R.V.; Murchie, S.L.; Parker, T.J.; Paulsen, G.; Rice, J.W.; Ruff, S.W.; Smith, M.D.; Wolff, M.J.

    2014-01-01

    Opportunity has investigated in detail rocks on the rim of the Noachian age Endeavour crater, where orbital spectral reflectance signatures indicate the presence of Fe+3-rich smectites. The signatures are associated with fine-grained, layered rocks containing spherules of diagenetic or impact origin. The layered rocks are overlain by breccias, and both units are cut by calcium sulfate veins precipitated from fluids that circulated after the Endeavour impact. Compositional data for fractures in the layered rocks suggest formation of Al-rich smectites by aqueous leaching. Evidence is thus preserved for water-rock interactions before and after the impact, with aqueous environments of slightly acidic to circum-neutral pH that would have been more favorable for prebiotic chemistry and microorganisms than those recorded by younger sulfate-rich rocks at Meridiani Planum.

  1. Software industrial flexible

    Díaz Araya, Daniel; Muñoz, Leandro; Sirerol, Daniel; Oviedo, Sandra; Ibáñez, Francisco S.

    2012-01-01

    En este trabajo se pretende investigar y proponer técnicas, métodos y tecnologías que permitan el desarrollo de software flexible en ambientes industriales. El objetivo es generar métodos y técnicas para facilitar el desarrollo de software flexible en ambientes industriales. Las áreas de investigación son los sistemas de scheduling de producción, la generación de software para plataformas de hardware abiertas y la innovación.

  2. Production Flexibility and Hedging

    Georges Dionne

    2015-12-01

    Full Text Available We extend the analysis on hedging with price and output uncertainty by endogenizing the output decision. Specifically, we consider the joint determination of output and hedging in the case of flexibility in production. We show that the risk-averse firm always maintains a short position in the futures market when the futures price is actuarially fair. Moreover, in the context of an example, we show that the presence of production flexibility reduces the incentive to hedge for all risk averse agents.

  3. The flexibility of flexicurity

    Jensen, Carsten Strøby

    2011-01-01

    by a special relation between flexibility, social security and active labour market policy, where a high level of social security is seen as a precondition for a labour market characterized by flexibility. In this article it is argued that the Danish labour market is characterized by having not just one model...... of flexicurity, but two. These two models cover different parts of the labour market and different segments of employees. The first model (the blue-collar flexicurity model) – the one that is often focused on in the literature – covers primarily skilled and unskilled workers on the labour market. The second...

  4. Compositions comprising free-standing two-dimensional nanocrystals

    Barsoum, Michel W.; Gogotsi, Yury; Abdelmalak, Michael Naguib; Mashtalir, Olha

    2017-12-05

    The present invention is directed to methods of transferring urea from an aqueous solution comprising urea to a MXene composition, the method comprising contacting the aqueous solution comprising urea with the MXene composition for a time sufficient to form an intercalated MXene composition comprising urea.

  5. A review of flexible lithium-sulfur and analogous alkali metal-chalcogen rechargeable batteries.

    Peng, Hong-Jie; Huang, Jia-Qi; Zhang, Qiang

    2017-08-29

    Flexible energy storage systems are imperative for emerging flexible devices that are revolutionizing our life. Lithium-ion batteries, the current main power sources, are gradually approaching their theoretical limitation in terms of energy density. Therefore, alternative battery chemistries are urgently required for next-generation flexible power sources with high energy densities, low cost, and inherent safety. Flexible lithium-sulfur (Li-S) batteries and analogous flexible alkali metal-chalcogen batteries are of paramount interest owing to their high energy densities endowed by multielectron chemistry. In this review, we summarized the recent progress of flexible Li-S and analogous batteries. A brief introduction to flexible energy storage systems and general Li-S batteries has been provided first. Progress in flexible materials for flexible Li-S batteries are reviewed subsequently, with a detailed classification of flexible sulfur cathodes as those based on carbonaceous (e.g., carbon nanotubes, graphene, and carbonized polymers) and composite (polymers and inorganics) materials and an overview of flexible lithium anodes and flexible solid-state electrolytes. Advancements in other flexible alkali metal-chalcogen batteries are then introduced. In the next part, we emphasize the importance of cell packaging and flexibility evaluation, and two special flexible battery prototypes of foldable and cable-type Li-S batteries are highlighted. In the end, existing challenges and future development of flexible Li-S and analogous alkali metal-chalcogen batteries are summarized and prospected.

  6. Flexibility as a service

    Aalst, van der W.M.P.; Adams, M.; Hofstede, ter A.H.M.; Pesic, M.; Schonenberg, H.; Chen, L.; Liu, C.; Liu, Q.; Deng, K.

    2009-01-01

    The lack of flexibility is often seen as an inhibitor for the successful application of workflow technology. Many researchers have proposed different ways of addressing this problem and some of these ideas have been implemented in commercial systems. However, a "one size fits all" approach is likely

  7. Valuing Flexibility. Phase 2

    2012-10-29

    Quarterly (2): 38-49. Cormier, P., Olewnik, A., and Lewis, K. 2008. An Approach to Quantifying Design Flexibility for Mass Customization in Early...C. Clarkson, P., and Zanker, W. 2004. Change and customisation in complex engineering domains, Res Eng Des 15(1), 1–21. Ekstrom, M. and Bjornsson, H

  8. Flexible Query Answering Systems

    This book constitutes the refereed proceedings of the 12th International Conference on Flexible Query Answering Systems, FQAS 2017, held in London, UK, in June 2017. The 21 full papers presented in this book together with 4 short papers were carefully reviewed and selected from 43 submissions...

  9. Flexible metal bellows

    CERN PhotoLab

    1975-01-01

    A set of flexible metal bellows being fatigue-tested by repeated offset motion. Such bellows assemblies were used in the SPS vacuum system at places where , for instance, beam stoppers and collimators had to be moved frequently in and out of the beam path.

  10. Flexible energy systems

    Lund, Henrik

    2003-01-01

    The paper discusses and analyses diffent national strategies and points out key changes in the energy system in order to achieve a system which can benefit from a high percentage of wind and CHP without having surplus production problems, introduced here as a flexible energy system....

  11. A flexible WLAN receiver

    Schiphorst, Roelof; Hoeksema, F.W.; Slump, Cornelis H.

    2003-01-01

    Flexible radio receivers are also called Software Defined Radios (SDRs) [1], [2]. The focus of our SDR project [3] is on designing the front end, from antenna to demodulation in bits, of a °exible, multi-standard WLAN receiver. We try to combine an instance of a (G)FSK receiver (Bluetooth) with an

  12. Aqueous shunts for glaucoma.

    Tseng, Victoria L; Coleman, Anne L; Chang, Melinda Y; Caprioli, Joseph

    2017-07-28

    Aqueous shunts are employed to control intraocular pressure (IOP) for people with primary or secondary glaucomas who fail or are not candidates for standard surgery. To assess the effectiveness and safety of aqueous shunts for reducing IOP in glaucoma compared with standard surgery, another type of aqueous shunt, or modification to the aqueous shunt procedure. We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 8), MEDLINE Ovid (1946 to August 2016), Embase.com (1947 to August 2016), PubMed (1948 to August 2016), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to August 2016), ClinicalTrials.gov (www.clinicaltrials.gov); searched 15 August 2016, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en); searched 15 August 2016. We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 15 August 2016. We also searched the reference lists of identified trial reports and the Science Citation Index to find additional trials. We included randomized controlled trials that compared various types of aqueous shunts with standard surgery or to each other in eyes with glaucoma. Two review authors independently screened search results for eligibility, assessed the risk of bias, and extracted data from included trials. We contacted trial investigators when data were unclear or not reported. We graded the certainty of the evidence using the GRADE approach. We followed standard methods as recommended by Cochrane. We included 27 trials with a total of 2099 participants with mixed diagnoses and comparisons of interventions. Seventeen studies reported adequate methods of randomization, and seven reported adequate allocation concealment. Data collection and follow-up times varied.Four trials compared an aqueous shunt (Ahmed or Baerveldt) with trabeculectomy, of which

  13. Aqueous radioactive waste bituminization

    Williamson, A.S.

    1980-08-01

    The bituminzation of decontamination and ion exchange resin stripping wastes with four grades of asphalt was investigated to determine the effects of asphalt type on the properties of the final products. All waste forms deformed readily under light loads indicating they would flow if not restrained. It was observed in all cases that product leaching rates increased as the hardness of the asphalt used to treat the waste increased. If bituminization is adopted for any Ontario Hydro aqueous radioactive wastes they should be treated with soft asphalt to obtain optimum leaching resistance and mechanical stability during interim storage should be provided by a corrosion resistant container

  14. Mercury separation from aqueous wastes

    Taylor, P.A.; Klasson, K.T.; Corder, S.L.

    1995-07-01

    This project is providing an assessment of new sorbents for removing mercury from wastes at US Department of Energy sites. Four aqueous wastes were chosen for lab-scale testing; a high-salt, acidic waste currently stored at Idaho National Engineering Laboratory (INEL); a high-salt, alkaline waste stored at the Savannah River Site (SRS); a dilute lithium hydroxide solution stored at the Oak Ridge Y-12 Plant; and a low-salt, neutral groundwater generated at the Y-12 Plant. Eight adsorbents have been identified for testing, covering a wide range of cost and capability. Screening tests have been completed, which identified the most promising adsorbents for each waste stream. Batch isotherm tests have been completed using the most promising adsorbents, and column tests are in progress. Because of the wide range of waste compositions tested, no one adsorbent is effective in all of these waste streams. Based on loading capacity and compatibility with the waste solutions. the most effective adsorbents identified to date are SuperLig 618 for the INEL tank waste stimulant; Mersorb followed by lonac SR-3 for the SRS tank waste stimulant; Durasil 70 and Ionac SR-3) for the LIOH solution; and lonac SR-3 followed by lonac SR-4 and Mersorb for the Y-12 groundwater

  15. Energy Flexibility in Retail Buildings

    Ma, Zheng; Billanes, Joy Dalmacio; Kjærgaard, Mikkel Baun

    2017-01-01

    Retail buildings has an important role for demand side energy flexibility because of their high energy consumption, variety of energy flexibility resources, and centralized control via building control systems. Energy flexibility requires agreements and collaborations among different actors......), with the discussion of the stakeholders’ roles and their interrelation in delivering energy flexibility with the influential factors to the actual implementation of energy flexible operation of their buildings. Based on a literature analysis, the results cover stakeholders’ types and roles, perceptions (drivers......, barriers, and benefits), energy management activities and technology adoptions, and the stakeholders’ interaction for the energy flexibility in retail buildings....

  16. Water-soluble Microwave-exfoliated Graphene Nanosheet/Platinum Nanoparticle Composite and Its Application in Dye-Sensitized Solar Cells

    Zhai, Peng; Chang, Ya-Huei; Huang, Yu-Ting; Wei, Tzu-Chien; Su, Haijun; Feng, Shien-Ping

    2014-01-01

    In this paper, a facile and scalable aqueous process including mild oxidative intercalation, microwave exfoliation, ultrasonication, drying and Ar-annealing is developed to synthesize the water-soluble microwave-exfoliated graphene (MEG)/platinum nanoparticles (PtNPs) composite, which has a relative low defect level and can be readily dispersed in deionized water without adding surfactants. This low cost synthesis method is applicable in many systems, such as supercapacitors, thermal storage, lithium battery and Dye-sensitized solar cells (DSSCs). An efficiency of 6.69% for the MEG/PtNPs composite deposited on ITO PEN as flexible counter electrode (CE) for DSSCs has been obtained, higher than the control device made by PVP-Pt as flexible CE

  17. Segregative phase separation in aqueous mixtures of polydisperse biopolymers

    Edelman, M.W.

    2003-01-01

    Keywords: biopolymer, gelatine, dextran, PEO, phase separation, polydispersity, molar mass distribution, SEC-MALLS, CSLM The temperature-composition phase diagram of aqueous solutions of gelatine and dextran, which show liquid/liquid phase segregation, were explored at temperatures above the

  18. Carbon coated textiles for flexible energy storage

    Jost, Kristy [Drexel Univ., Philadelphia, PA (United States). Fashion, Product, Design and Merchandising Dept., A. J. Drexel Nanotechnology Inst. and Dept. of Materials Science and Engineering; Perez, Carlos R. [Drexel Univ., Philadelphia, PA (United States). A. J. Drexel Nanotechnology Inst. and Dept. of Materials Science and Engineering; McDonough, John K. [Drexel Univ., Philadelphia, PA (United States). A. J. Drexel Nanotechnology Inst. and Dept. of Materials Science and Engineering; Presser, Volker [Drexel Univ., Philadelphia, PA (United States). A. J. Drexel Nanotechnology Inst. and Dept. of Materials Science and Engineering; Heon, Min [Drexel Univ., Philadelphia, PA (United States). A. J. Drexel Nanotechnology Inst. and Dept. of Materials Science and Engineering; Dion, Genevieve [Drexel Univ., Philadelphia, PA (United States). Fashion, Product, Design and Merchandising Dept.; Gogotsi, Yury [Drexel Univ., Philadelphia, PA (United States). A. J. Drexel Nanotechnology Inst. and Dept. of Materials Science and Engineering

    2011-10-20

    This paper describes a flexible and lightweight fabric supercapacitor electrode as a possible energy source in smart garments. We examined the electrochemical behavior of porous carbon materials impregnated into woven cotton and polyester fabrics using a traditional printmaking technique (screen printing). The porous structure of such fabrics makes them attractive for supercapacitor applications that need porous films for ion transfer between electrodes. We used cyclic voltammetry, galvanostatic cycling and electrochemical impedance spectroscopy to study the capacitive behaviour of carbon materials using nontoxic aqueous electrolytes including sodium sulfate and lithium sulfate. Electrodes coated with activated carbon (YP17) and tested at ~0.25 A·g⁻¹ achieved a high gravimetric and areal capacitance, an average of 85 F·g⁻¹ on cotton lawn and polyester microfiber, both corresponding to ~0.43 F·cm⁻².

  19. Mars aqueous chemistry experiment

    Clark, Benton C.; Mason, Larry W.

    1994-06-01

    Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. The second year of the MACE project has shown significant progress in two major areas. MACE Instrument concept definition is a baseline design that has been generated for the complete MACE instrument, including definition of analysis modes, mass estimates and thermal model. The design includes multiple reagent reservoirs, 10 discrete analysis cells, sample manipulation capability, and thermal control. The MACE Measurement subsystems development progress is reported regarding measurement capabilities for aqueous ion sensing, evolved gas sensing, solution conductivity measurement, reagent addition (titration) capabilities, and optical sensing of suspended particles.

  20. Mars aqueous chemistry experiment

    Clark, Benton C.; Mason, Larry W.

    1994-01-01

    Mars Aqueous Chemistry Experiment (MACE) is designed to conduct a variety of measurements on regolith samples, encompassing mineral phase analyses, chemical interactions with H2O, and physical properties determinations. From these data, much can be learned or inferred regarding the past weathering environment, the contemporaneous soil micro-environments, and the general chemical and physical state of the Martian regolith. By analyzing both soil and duricrust samples, the nature of the latter may become more apparent. Sites may be characterized for comparative purposes and criteria could be set for selection of high priority materials on future sample return missions. The second year of the MACE project has shown significant progress in two major areas. MACE Instrument concept definition is a baseline design that has been generated for the complete MACE instrument, including definition of analysis modes, mass estimates and thermal model. The design includes multiple reagent reservoirs, 10 discrete analysis cells, sample manipulation capability, and thermal control. The MACE Measurement subsystems development progress is reported regarding measurement capabilities for aqueous ion sensing, evolved gas sensing, solution conductivity measurement, reagent addition (titration) capabilities, and optical sensing of suspended particles.

  1. Diffusion in flexible pipes

    Brogaard Kristensen, S.

    2000-06-01

    This report describes the work done on modelling and simulation of the complex diffusion of gas through the wall of a flexible pipe. The diffusion and thus the pressure in annulus depends strongly on the diffusion and solubility parameters of the gas-polymer system and on the degree of blocking of the outer surface of the inner liner due to pressure reinforcements. The report evaluates the basis modelling required to describe the complex geometries and flow patterns. Qualitatively results of temperature and concentration profiles are shown in the report. For the program to serve any modelling purpose in 'real life' the results need to be validated and possibly the model needs corrections. Hopefully, a full-scale test of a flexible pipe will provide the required temperatures and pressures in annulus to validate the models. (EHS)

  2. Flexible cryogenic conduit

    Brindza, P.D.; Wines, R.R.; Takacs, J.J.

    1999-01-01

    A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament

  3. Diffusion in flexible pipes

    Brogaard Kristensen, S

    2000-06-01

    This report describes the work done on modelling and simulation of the complex diffusion of gas through the wall of a flexible pipe. The diffusion and thus the pressure in annulus depends strongly on the diffusion and solubility parameters of the gas-polymer system and on the degree of blocking of the outer surface of the inner liner due to pressure reinforcements. The report evaluates the basis modelling required to describe the complex geometries and flow patterns. Qualitatively results of temperature and concentration profiles are shown in the report. For the program to serve any modelling purpose in 'real life' the results need to be validated and possibly the model needs corrections. Hopefully, a full-scale test of a flexible pipe will provide the required temperatures and pressures in annulus to validate the models. (EHS)

  4. Flexible Laser Metal Cutting

    Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

    2014-01-01

    This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...... possess, despite their wide use in industry, limitations regarding speed and geometry. Research trends point towards remote laser cutting techniques which can improve speed and geometrical freedom and hereby the competitiveness of laser cutting compared to fixed-tool-based cutting technology...... such as punching. This paper presents the concepts and preliminary test results of the ROBOCUT laser cutting technology, a technology which potentially can revolutionise laser cutting....

  5. The Effect of Aqueous Alteration on Primordial Noble Gases in CM Chondrites

    Weimer, D.; Busemann, H.; Alexander, C. M. O'D.; Maden, C.

    2017-07-01

    We have analyzed 32 CM chondrites for their noble gas contents and isotopic compositions and calculated CRE ages. Correlated effects of parent body aqueous alteration with primordial noble gas contents were detected.

  6. Flexible training under threat.

    Houghton, Anita; Eaton, Jennifer

    2002-10-01

    As the number of women in medicine and the general demand for a better work-life balance rises, flexible training is an increasingly important mechanism for maintaining the medical workforce. The new pay deal, together with entrenched cultural attitudes, are potential threats. Ways forward include more substantive part-time posts, more part-time opportunities at consultant level, and using positive experiences as a way of tackling attitudes in the less accepting specialties.

  7. Flexible weapons architecture design

    Pyant, William C.

    2015-01-01

    Present day air-delivered weapons are of a closed architecture, with little to no ability to tailor the weapon for the individual engagement. The closed architectures require weaponeers to make the target fit the weapon instead of fitting the individual weapons to a target. The concept of a flexible weapons aims to modularize weapons design using an open architecture shell into which different modules are inserted to achieve the desired target fractional damage while reducing cost and civilia...

  8. Industrial Fuel Flexibility Workshop

    none,

    2006-09-01

    On September 28, 2006, in Washington, DC, ITP and Booz Allen Hamilton conducted a fuel flexibility workshop with attendance from various stakeholder groups. Workshop participants included representatives from the petrochemical, refining, food and beverage, steel and metals, pulp and paper, cement and glass manufacturing industries; as well as representatives from industrial boiler manufacturers, technology providers, energy and waste service providers, the federal government and national laboratories, and developers and financiers.

  9. Flexible Land Administration

    Enemark, Stig

    2014-01-01

    Security of tenure is widely considered to be the missing piece of the puzzle when it comes to eradication of poverty. And, as explained in the previous issue of Geoinformatics, the European Union is now placing land rights at the heart of EU development policy. This article presents a way forwar...... in terms of building flexible and "fit-for-purpose" land administration systems in developing countries. This will ensure security of tenure for all and sustainable management of the use of land....

  10. PTFE films with improved flexibility

    Muraca, R. F.; Koch, A. A.

    1972-01-01

    Development and application of flexible polytetrafluroethylene films for expulsion bladders in spacecraft propellant tanks are described. Flexibility of material is obtained by reducing crystallinity through annealing and quenching in water. Physical and mechanical properties of material are presented.

  11. Aqueous electrolytes for redox flow battery systems

    Liu, Tianbiao; Li, Bin; Wei, Xiaoliang; Nie, Zimin; Wang, Wei; Liu, Jun; Sprenkle, Vincent L.

    2017-10-17

    An aqueous redox flow battery system includes an aqueous catholyte and an aqueous anolyte. The aqueous catholyte may comprise (i) an optionally substituted thiourea or a nitroxyl radical compound and (ii) a catholyte aqueous supporting solution. The aqueous anolyte may comprise (i) metal cations or a viologen compound and (ii) an anolyte aqueous supporting solution. The catholyte aqueous supporting solution and the anolyte aqueous supporting solution independently may comprise (i) a proton source, (ii) a halide source, or (iii) a proton source and a halide source.

  12. Flexible automated manufacturing for SMEs

    Grube Hansen, David; Bilberg, Arne; Madsen, Erik Skov

    2017-01-01

    SMEs are in general highly flexible and agile in order to accommodate the customer demands in the paradigm of High Mix-Low Volume manufacturing. The flexibility and agility have mainly been enabled by manual labor, but as we are entering the technology and data driven fourth industrial revolution......, where augmented operators and machines work in cooperation in a highly flexible and productive manufacturing system both an opportunity and a need has raised for developing highly flexible and efficient automation....

  13. Gas-Phase Functionalization of Macroscopic Carbon Nanotube Fiber Assemblies: Reaction Control, Electrochemical Properties, and Use for Flexible Supercapacitors.

    Iglesias, Daniel; Senokos, Evgeny; Alemán, Belén; Cabana, Laura; Navío, Cristina; Marcilla, Rebeca; Prato, Maurizio; Vilatela, Juan J; Marchesan, Silvia

    2018-02-14

    The assembly of aligned carbon nanotubes (CNTs) into fibers (CNTFs) is a convenient approach to exploit and apply the unique physico-chemical properties of CNTs in many fields. CNT functionalization has been extensively used for its implementation into composites and devices. However, CNTF functionalization is still in its infancy because of the challenges associated with preservation of CNTF morphology. Here, we report a thorough study of the gas-phase functionalization of CNTF assemblies using ozone which was generated in situ from a UV source. In contrast with liquid-based oxidation methods, this gas-phase approach preserves CNTF morphology, while notably increasing its hydrophilicity. The functionalized material is thoroughly characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy. Its newly acquired hydrophilicity enables CNTF electrochemical characterization in aqueous media, which was not possible for the pristine material. Through comparison of electrochemical measurements in aqueous electrolytes and ionic liquids, we decouple the effects of functionalization on pseudocapacitive reactions and quantum capacitance. The functionalized CNTF assembly is successfully used as an active material and a current collector in all-solid supercapacitor flexible devices with an ionic liquid-based polymer electrolyte.

  14. Designing structural supply chain flexibility

    Mulinski, Ksawery Jan

    2012-01-01

    In a continuously changing business environment the role of supply chain flexibility is constantly increasing. A flexible supply chain can ensure survival in quickly changing market conditions as well as enable sustainable growth. This thesis explores the topic of supply chain flexibility with focus

  15. Global Analysis of Flexible Risers

    Banke, Lars

    1996-01-01

    Flexible pipes are often a technically attractive alternative to the traditional steel pipe. Often commercial utilisation of oil/gas fields depends on the use of flexible pipes. An example is when floating production vessels are used, where the flexible pipe follows the wave induced motions...

  16. Conductive polymer composition

    2010-01-01

    The present invention relates to a process for the preparation of a conductive polymer composition comprising graphene and the articles obtained by this process. The process comprises the following steps: A) contacting graphite oxide in an aqueous medium with a water-soluble or dispersible

  17. The aqueous chemistry of oxides

    Bunker, Bruce C

    2016-01-01

    The Aqueous Chemistry of Oxides is a comprehensive reference volume and special topics textbook that explores all of the major chemical reactions that take place between oxides and aqueous solutions. The book highlights the enormous impact that oxide-water reactions have in advanced technologies, materials science, geochemistry, and environmental science.

  18. Aqueous reprocessing - some dreams!

    Srinivasan, T.G.

    2015-01-01

    India has been pursuing a aqueous reprocessing based closed fuel cycle for both thermal and fast reactor fuels employing the PUREX process. Though the country has more than six decades of experience, the dreams or wish lists such as, a highly efficient process with textbook specifications of 99.9% recovery of U and Pu, a DF of more than 10 7 for both U and Pu from the fission products, operating with name plate capacity with high safety, low waste generation, recovery of useful fission products and minor actinides from high level waste are never ceasing and ever growing. The talk will cover safety precautions and actions to be taken in the steps listed below, to ensure a safe and successful process

  19. Aqueous chemical dosimetry

    Matthews, R.W.

    1982-01-01

    Aqueous chemical dosimetry based on ceric and ferrous sulfate solutions and on a number of fluorescence-induced systems is reviewed. Particular attention is given to the factors affecting the response of these dosimeters to radiation and the corrections necessary for more accurate dosimetry under various irradiation conditions. The effect of cerous and ceric ion, oxygen, and sulfuric acid concentration on the ceric dosimeter is discussed together with the effects of temperature, energy of radiation, degraded energy spectra, and peroxysulfuric acids. Practical aspects of ceric/cerous dosimetry are given. Although ferrous sulfate solution is the most important and widely studied reference dosimeter, general agreement has not been reached on the ''best'' value for the molar extinction coefficient of ferric ions nor on the correction necessary to the G(Fe 3 - ) value for irradiations at temperatures significantly different from 25 0 C. New data are presented which indicate that the larger temperature coefficients given in the literature are more accurate. The ferrous sulfate system has been of great importance in establishing the primary radiolytic yields for 0.4 M sulfuric acid solution; it is shown how the failure to take into account the effect of oxygen and ferrous sulfate concentrations has led to erroneously high estimates of the zero solute concentration values in acid solutions. Some of the methods for extending the dose ranges measurable with ferrous sulfate-based solutions are reviewed. Substances which on irradiation give highly fluorescent products are among the most sensitive aqueous chemical dosimeters. These include benzoate and terephthalate solutions and the more recent coumarin and trimesate solutions. Advantages and disadvantages system are discussed. (author)

  20. Flexible Query Answering Systems

    This book constitutes the refereed proceedings of the 10th International Conference on Flexible Query Answering Systems, FQAS 2013, held in Granada, Spain, in September 2013. The 59 full papers included in this volume were carefully reviewed and selected from numerous submissions. The papers...... are organized in a general session train and a parallel special session track. The general session train covers the following topics: querying-answering systems; semantic technology; patterns and classification; personalization and recommender systems; searching and ranking; and Web and human...

  1. Active vibration control of spatial flexible multibody systems

    Neto, Maria Augusta, E-mail: augusta.neto@dem.uc.pt [Universidade de Coimbra (Polo II), Departamento de Engenharia Mecanica, Faculdade de Ciencia e Tecnologia (Portugal); Ambrosio, Jorge A. C., E-mail: jorge@dem.ist.utl.pt [Instituto Superior Tecnico, Instituto de Engenharia Mecanica (Portugal); Roseiro, Luis M., E-mail: lroseiro@isec.pt [Instituto Superior de Engenharia de Coimbra, Departamento de Engenharia Mecanica (Portugal); Amaro, A., E-mail: ana.amaro@dem.uc.pt [Universidade de Coimbra (Polo II), Departamento de Engenharia Mecanica, Faculdade de Ciencia e Tecnologia (Portugal); Vasques, C. M. A., E-mail: cvasques@inegi.up.pt [Universidade do Porto, INEGI-Instituto de Engenharia Mecanica e Gestao Industrial (Portugal)

    2013-06-15

    In this work a flexible multibody dynamics formulation of complex models including elastic components made of composite materials is extended to include piezoelectric sensors and actuators. The only limitation for the deformation of a structural member is that they must remain elastic and linear when described in a coordinate frame fixed to a material point or region of its domain. The flexible finite-element model of each flexible body is obtained referring the flexible body nodal coordinates to the body fixed frame and using a diagonalized mass description of the inertia in the mass matrix and on the gyroscopic force vector. The modal superposition technique is used to reduce the number of generalized coordinates to a reasonable dimension for complex shaped structural models of flexible bodies. The active vibration control of the flexible multibody components is implemented using an asymmetric collocated piezoelectric sensor/actuator pair. An electromechanically coupled model is taken into account to properly consider the surface-bonded piezoelectric transducers and their effects on the time and spatial response of the flexible multibody components. The electromechanical effects are introduced in the flexible multibody equations of motion by the use of beam and plate/shell elements, developed to this purpose. A comparative study between the classical control strategies, constant gain and amplitude velocity feedback, and optimal control strategy, linear quadratic regulator (LQR), is performed in order to investigate their effectiveness to suppress vibrations in structures with piezoelectric sensing and actuating patches.

  2. Active vibration control of spatial flexible multibody systems

    Neto, Maria Augusta; Ambrósio, Jorge A. C.; Roseiro, Luis M.; Amaro, A.; Vasques, C. M. A.

    2013-01-01

    In this work a flexible multibody dynamics formulation of complex models including elastic components made of composite materials is extended to include piezoelectric sensors and actuators. The only limitation for the deformation of a structural member is that they must remain elastic and linear when described in a coordinate frame fixed to a material point or region of its domain. The flexible finite-element model of each flexible body is obtained referring the flexible body nodal coordinates to the body fixed frame and using a diagonalized mass description of the inertia in the mass matrix and on the gyroscopic force vector. The modal superposition technique is used to reduce the number of generalized coordinates to a reasonable dimension for complex shaped structural models of flexible bodies. The active vibration control of the flexible multibody components is implemented using an asymmetric collocated piezoelectric sensor/actuator pair. An electromechanically coupled model is taken into account to properly consider the surface-bonded piezoelectric transducers and their effects on the time and spatial response of the flexible multibody components. The electromechanical effects are introduced in the flexible multibody equations of motion by the use of beam and plate/shell elements, developed to this purpose. A comparative study between the classical control strategies, constant gain and amplitude velocity feedback, and optimal control strategy, linear quadratic regulator (LQR), is performed in order to investigate their effectiveness to suppress vibrations in structures with piezoelectric sensing and actuating patches.

  3. Flexible barrier film, method of forming same, and organic electronic device including same

    Blizzard, John; Tonge, James Steven; Weidner, William Kenneth

    2013-03-26

    A flexible barrier film has a thickness of from greater than zero to less than 5,000 nanometers and a water vapor transmission rate of no more than 1.times.10.sup.-2 g/m.sup.2/day at 22.degree. C. and 47% relative humidity. The flexible barrier film is formed from a composition, which comprises a multi-functional acrylate. The composition further comprises the reaction product of an alkoxy-functional organometallic compound and an alkoxy-functional organosilicon compound. A method of forming the flexible barrier film includes the steps of disposing the composition on a substrate and curing the composition to form the flexible barrier film. The flexible barrier film may be utilized in organic electronic devices.

  4. Modelling the liquid-liquid extraction of nitric acid and lanthanide nitrates by tributylphosphate. Study of the influence of the aqueous phase composition on the selectivity of rare earth separation

    Mokili, Bandombele

    1992-01-01

    This research thesis reports the application of advances in the modelling of liquid-liquid extraction to a quantitative processing of the selectivity of separations. It is here applied to the extraction-based separation of lanthanide nitrates by using the tributylphosphate (TBP) in nitric environment as this system is interesting for industrial applications in hydro-metallurgy of rare earths as well as in the processing of irradiated nuclear fuels. Experimental data are acquired and then used in the Mikulin-Sergievskii-Dannus model. Complete modelling is thus obtained which allowed the complex problem of extraction of nitric acid and of lanthanide to be addressed, and the existence of a hybrid solvate to be supported. A mathematical expression of the separation factor of two lanthanides is proposed and used to highlight its influencing parameters, i.e. water activity in the aqueous phase, and the rate of the effective extraction constants of the two elements to be separated. Experimental observations are thus interpreted. The selection of optimal separation conditions is thus justified, and, in some cases, the system selectivity can be predicted [fr

  5. Anion-conducting polymer, composition, and membrane

    Pivovar, Bryan S [Los Alamos, NM; Thorn, David L [Los Alamos, NM

    2009-09-01

    Anion-conducing polymers and membranes with enhanced stability to aqueous alkali include a polymer backbone with attached sulfonium, phosphazenium, phosphazene, and guanidinium residues. Compositions also with enhanced stability to aqueous alkali include a support embedded with sulfonium, phosphazenium, and guanidinium salts.

  6. Aqueous chemistry of transactinides

    Schaedel, M.

    2001-01-01

    The aqueous chemistry of the first three transactinide elements is briefly reviewed with special emphasis given to recent experimental results. Short introductory remarks are discussing the atom-at-a-time situation of transactinide chemistry as a result of low production cross-sections and short half-lives. In general, on-line experimental techniques and, more specifically, the automated rapid chemistry apparatus, ARCA, are presented. Present and future developments of experimental techniques and resulting perspectives are outlined at the end. The central part is mainly focussing on hydrolysis and complex formation aspects of the superheavy group 4, 5, and 6 transition metals with F - and Cl - anions. Experimental results are compared with the behaviour of lighter homologous elements and with relativistic calculations. It will be shown that the chemical behaviour of the first superheavy elements is already strongly influenced by relativistic effects. While it is justified to place rutherfordium, dubnium and seaborgium in the Periodic Table of the Elements into group 4, 5 and 6, respectively, it is no more possible to deduce from this position in detail the chemical properties of these transactinide or superheavy elements. (orig.)

  7. Aqueous solubility, dispersibility and toxicity of biodiesels

    Hollebone, B.P.; Fieldhouse, B.; Lumley, T.C.; Landriault, M.; Doe, K.; Jackman, P.

    2007-01-01

    The renewed interest in the use of biological fuels can be attributed to that fact that feedstocks for fatty-acid ester biodiesels are renewable and can be reclaimed from waste. Although there are significant benefits to using biodiesels, their increased use leaves potential for accidental release to the environment. Therefore, their environmental behaviours and impacts must be evaluated along with the risk associated with their use. Biodiesel fuels may be made from soy oil, canola oil, reclaimed restaurant grease, fish oil and animal fat. The toxicological fate of biofuel depends on the variability of its chemical composition. This study provided an initial assessment of the aqueous fate and effects of biodiesel from a broad range of commonly available feedstocks and their blends with petroleum diesels. The study focused primarily on the fate and impact of these fuels in fresh-water. The use of chemical dispersion as a countermeasure for saltwater was also investigated. The exposure of aquatic ecosystems to biodiesels and petroleum diesel occurs via the transfer of material from the non-aqueous phase liquid (NAPL) into the aqueous phase, as both soluble and dispersed components. The aqueous solubilities of the fuels were determined from the equilibrium water-accommodated fraction concentrations. The acute toxicities of many biodiesels were reported for 3 test species used by Environment Canada for toxicological evaluation, namely rainbow trout, the water flea and a luminescent bacterium. This study also evaluated the natural potential for dispersion of the fuels in the water column in both low and high-energy wave conditions. Chemical dispersion as a potential countermeasure for biodiesel spills was also evaluated using solubility testing, acute toxicity testing, and dispersibility testing. It was shown that biodiesels have much different fates and impacts from petroleum diesels. The compounds partitioning into the water column are also very different for each

  8. On flexible and rigid nouns

    Rijkhoff, Jan

    2010-01-01

    classes. Finally this article wants to claim that the distinction between rigid and flexible noun categories (a) adds a new dimension to current classifications of parts of speech systems, (b) correlates with certain grammatical phenomena (e.g. so-called number discord), and (c) helps to explain the parts......This article argues that in addition to the major flexible lexical categories in Hengeveld’s classification of parts of speech systems (Contentive, Non-Verb, Modifier), there are also flexible word classes within the rigid lexical category Noun (Set Noun, Sort Noun, General Noun). Members...... by the flexible item in the external world. I will then argue that flexible word classes constitute a proper category (i.e. they are not the result of a merger of some rigid word classes) in that members of flexible word categories display the same properties regarding category membership as members of rigid word...

  9. On flexible and rigid nouns

    Rijkhoff, Jan

    2008-01-01

    Studies in Language 32-3 (2008), 727-752. Special issue: Parts of Speech: Descriptive tools, theoretical constructs Jan Rijkhoff - On flexible and rigid nouns This article argues that in addition to the flexible lexical categories in Hengeveld’s classification of parts-of-speech systems (Contentive......, Non-Verb, Modifier), there are also flexible word classes within the rigid lexical category Noun (Set Noun, Sort Noun, General Noun). Members of flexible word classes are characterized by their vague semantics, which in the case of nouns means that values for the semantic features Shape...... and Homogeneity are either left undetermined or they are specified in such a way that they do not quite match the properties of the kind of entity denoted by the flexible item in the external world. I will then argue that flexible word classes constitute a proper category (i.e. they are not the result of a merger...

  10. Flexible Language Interoperability

    Ekman, Torbjörn; Mechlenborg, Peter; Schultz, Ulrik Pagh

    2007-01-01

    Virtual machines raise the abstraction level of the execution environment at the cost of restricting the set of supported languages. Moreover, the ability of a language implementation to integrate with other languages hosted on the same virtual machine typically constrains the features...... of the language. In this paper, we present a highly flexible yet efficient approach to hosting multiple programming languages on an object-oriented virtual machine. Our approach is based on extending the interface of each class with language-specific wrapper methods, offering each language a tailored view...... of a given class. This approach can be deployed both on a statically typed virtual machine, such as the JVM, and on a dynamic virtual machine, such as a Smalltalk virtual machine. We have implemented our approach to language interoperability on top of a prototype virtual machine for embedded systems based...

  11. Flexible cultural repertoires

    Lindegaard, Marie Rosenkrantz; Zimmermann, Francisca

    2017-01-01

    Despite extensive studies of street culture and the risks of offending and victimization in urban marginalized areas, little is known about the role of cultural repertoires for variation in victimization risks among young men not involved in crime. Based on two ethnographic studies, conducted...... independently of the authors in neighbouring township areas of Cape Town, we offer insights into patterns of victimization among young men not involved in crime who live and attend school in the townships. Young men WHO perform decent cultural repertoires are highly exposed to victimization due to their moral...... rejection of crime-involved youth. Young men who perform flexible cultural repertoires, by incorporating and shifting between gang and decent repertoires, experience low victimization due to their adaptation to crime-involved youth. Findings emphasize the importance of detailed investigations of the way...

  12. Flexible helical yarn swimmers.

    Zakharov, A P; Leshansky, A M; Pismen, L M

    2016-09-01

    We investigate the motion of a flexible Stokesian flagellar swimmer realised as a yarn made of two intertwined elastomer fibres, one active, that can reversibly change its length in response to a local excitation causing transition to the nematic state or swelling, and the other one, a passive isotropic elastomer with identical mechanical properties. A propagating chemical wave may provide an excitation mechanism ensuring a constant length of the excited region. Generally, the swimmer moves along a helical trajectory, and the propagation and rotation velocity are very sensitive to the ratio of the excited region to the pitch of the yarn, as well as to the size of a carried load. External excitation by a moving actuating beam is less effective, unless the direction of the beam is adjusted to rotation of the swimmer.

  13. Flexible weapons architecture design

    Pyant, William C., III

    Present day air-delivered weapons are of a closed architecture, with little to no ability to tailor the weapon for the individual engagement. The closed architectures require weaponeers to make the target fit the weapon instead of fitting the individual weapons to a target. The concept of a flexible weapons aims to modularize weapons design using an open architecture shell into which different modules are inserted to achieve the desired target fractional damage while reducing cost and civilian casualties. This thesis shows that the architecture design factors of damage mechanism, fusing, weapons weight, guidance, and propulsion are significant in enhancing weapon performance objectives, and would benefit from modularization. Additionally, this thesis constructs an algorithm that can be used to design a weapon set for a particular target class based on these modular components.

  14. Conformational flexibility of aspartame.

    Toniolo, Claudio; Temussi, Pierandrea

    2016-05-01

    L-Aspartyl-L-phenylalanine methyl ester, better known as aspartame, is not only one of the most used artificial sweeteners, but also a very interesting molecule with respect to the correlation between molecular structure and taste. The extreme conformational flexibility of this dipeptide posed a huge difficulty when researchers tried to use it as a lead compound to design new sweeteners. In particular, it was difficult to take advantage of its molecular model as a mold to infer the shape of the, then unknown, active site of the sweet taste receptor. Here, we follow the story of the 3D structural aspects of aspartame from early conformational studies to recent docking into homology models of the receptor. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 376-384, 2016. © 2016 Wiley Periodicals, Inc.

  15. Progress in aqueous rechargeable batteries

    Jilei Liu

    2018-01-01

    Full Text Available Over the past decades, a series of aqueous rechargeable batteries (ARBs were explored, investigated and demonstrated. Among them, aqueous rechargeable alkali-metal ion (Li+, Na+, K+ batteries, aqueous rechargeable-metal ion (Zn2+, Mg2+, Ca2+, Al3+ batteries and aqueous rechargeable hybrid batteries are standing out due to peculiar properties. In this review, we focus on the fundamental basics of these batteries, and discuss the scientific and/or technological achievements and challenges. By critically reviewing state-of-the-art technologies and the most promising results so far, we aim to analyze the benefits of ARBs and the critical issues to be addressed, and to promote better development of ARBs.

  16. aqueous root extract on spermatogenesis

    Four groups were gavaged with the whole plant or root aqueous extract in low or high doses. The male ... motility and morphology as well as chromatin integrity were evaluated. Results: Serum ... Treatment of disease began long ago with the.

  17. Exfoliation of graphite into graphene in aqueous solutions of inorganic salts.

    Parvez, Khaled; Wu, Zhong-Shuai; Li, Rongjin; Liu, Xianjie; Graf, Robert; Feng, Xinliang; Müllen, Klaus

    2014-04-23

    Mass production of high-quality graphene sheets is essential for their practical application in electronics, optoelectronics, composite materials, and energy-storage devices. Here we report a prompt electrochemical exfoliation of graphene sheets into aqueous solutions of different inorganic salts ((NH4)2SO4, Na2SO4, K2SO4, etc.). Exfoliation in these electrolytes leads to graphene with a high yield (>85%, ≤3 layers), large lateral size (up to 44 μm), low oxidation degree (a C/O ratio of 17.2), and a remarkable hole mobility of 310 cm(2) V(-1) s(-1). Further, highly conductive graphene films (11 Ω sq(-1)) are readily fabricated on an A4-size paper by applying brush painting of a concentrated graphene ink (10 mg mL(-1), in N,N'-dimethylformamide). All-solid-state flexible supercapacitors manufactured on the basis of such graphene films deliver a high area capacitance of 11.3 mF cm(-2) and an excellent rate capability of 5000 mV s(-1). The described electrochemical exfoliation shows great promise for the industrial-scale synthesis of high-quality graphene for numerous advanced applications.

  18. Automated determination of the stable carbon isotopic composition (δ13C) of total dissolved inorganic carbon (DIC) and total nonpurgeable dissolved organic carbon (DOC) in aqueous samples: RSIL lab codes 1851 and 1852

    Révész, Kinga M.; Doctor, Daniel H.

    2014-01-01

    The purposes of the Reston Stable Isotope Laboratory (RSIL) lab codes 1851 and 1852 are to determine the total carbon mass and the ratio of the stable isotopes of carbon (δ13C) for total dissolved inorganic carbon (DIC, lab code 1851) and total nonpurgeable dissolved organic carbon (DOC, lab code 1852) in aqueous samples. The analysis procedure is automated according to a method that utilizes a total carbon analyzer as a peripheral sample preparation device for analysis of carbon dioxide (CO2) gas by a continuous-flow isotope ratio mass spectrometer (CF-IRMS). The carbon analyzer produces CO2 and determines the carbon mass in parts per million (ppm) of DIC and DOC in each sample separately, and the CF-IRMS determines the carbon isotope ratio of the produced CO2. This configuration provides a fully automated analysis of total carbon mass and δ13C with no operator intervention, additional sample preparation, or other manual analysis. To determine the DIC, the carbon analyzer transfers a specified sample volume to a heated (70 °C) reaction vessel with a preprogrammed volume of 10% phosphoric acid (H3PO4), which allows the carbonate and bicarbonate species in the sample to dissociate to CO2. The CO2 from the reacted sample is subsequently purged with a flow of helium gas that sweeps the CO2 through an infrared CO2 detector and quantifies the CO2. The CO2 is then carried through a high-temperature (650 °C) scrubber reactor, a series of water traps, and ultimately to the inlet of the mass spectrometer. For the analysis of total dissolved organic carbon, the carbon analyzer performs a second step on the sample in the heated reaction vessel during which a preprogrammed volume of sodium persulfate (Na2S2O8) is added, and the hydroxyl radicals oxidize the organics to CO2. Samples containing 2 ppm to 30,000 ppm of carbon are analyzed. The precision of the carbon isotope analysis is within 0.3 per mill for DIC, and within 0.5 per mill for DOC.

  19. Toward flexible polymer and paper-based energy storage devices

    Nyholm, Leif [Department of Materials Chemistry, The Aangstroem Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala (Sweden); Nystroem, Gustav; Mihranyan, Albert; Stroemme, Maria [Nanotechnology and Functional Materials, Department of Engineering Sciences, The Aangstroem Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden)

    2011-09-01

    All-polymer and paper-based energy storage devices have significant inherent advantages in comparison with many currently employed batteries and supercapacitors regarding environmental friendliness, flexibility, cost and versatility. The research within this field is currently undergoing an exciting development as new polymers, composites and paper-based devices are being developed. In this report, we review recent progress concerning the development of flexible energy storage devices based on electronically conducting polymers and cellulose containing composites with particular emphasis on paper-based batteries and supercapacitors. We discuss recent progress in the development of the most commonly used electronically conducting polymers used in flexible device prototypes, the advantages and disadvantages of this type of energy storage devices, as well as the two main approaches used in the manufacturing of paper-based charge storage devices. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Research for improved flexible tactile sensor sensitivity

    Yun, Hae Yong; Kim, Ho Chan [Andong National University, Andong (Korea, Republic of); Lee, In Hwan [Chungbuk National University, Chungju (Korea, Republic of)

    2015-11-15

    With the development of robotic technologies, in recent years these technologies have been applied to multidisciplinary fields of study. To operate similarly to a human being, many robot technologies require devices that can receive exterior stimulus, temperature, visual data, and the sense of smell, etc. The robot's hand needs sensor devices that can receive exterior stimuli in order to operate similarly to human skin. The flexible tactile sensor for the robot has to be manufactured to have a shape similar to the shape of human skin. The research studied the development of a system and materials that will enable exterior stimuli to be received effectively. This research used carbon nano tube as a material. Carbon nano tube is used because it has a high electrical conductivity and outstanding mechanical characteristics. In addition, the two composite Materials are used to improve the stimulation sensitivity at different rates, the flexible tactile sensor to measure the sensitivity. Using 3D printing technology, the fabrication of a flexible tactile sensor system is introduced.

  1. Research for improved flexible tactile sensor sensitivity

    Yun, Hae Yong; Kim, Ho Chan; Lee, In Hwan

    2015-01-01

    With the development of robotic technologies, in recent years these technologies have been applied to multidisciplinary fields of study. To operate similarly to a human being, many robot technologies require devices that can receive exterior stimulus, temperature, visual data, and the sense of smell, etc. The robot's hand needs sensor devices that can receive exterior stimuli in order to operate similarly to human skin. The flexible tactile sensor for the robot has to be manufactured to have a shape similar to the shape of human skin. The research studied the development of a system and materials that will enable exterior stimuli to be received effectively. This research used carbon nano tube as a material. Carbon nano tube is used because it has a high electrical conductivity and outstanding mechanical characteristics. In addition, the two composite Materials are used to improve the stimulation sensitivity at different rates, the flexible tactile sensor to measure the sensitivity. Using 3D printing technology, the fabrication of a flexible tactile sensor system is introduced.

  2. Compositions and process for liquid scintillation counting

    Kauffman, J.M.

    1976-01-01

    Liquid scintillation counting compositions which include certain polyethoxylated poly(oxypropylene) emulsifiers allow stable dispersion of aqueous or other samples merely by shaking. Preferred are mixtures of such emulsifiers, which give homogeneous, monophasic-appearing dispersions over wide ranges of temperature and aqueous sample content. Certain of these emulsifiers, without being mixed, are of particular advantage when used in analysis of samples obtained through radioimmunoassay techniques, which are extremely difficult to disperse. Certain of these emulsifiers, also without being mixed, uniformly give homogeneous, monophasic appearing aqueous couting samples over much wider ranges of aqueous sample content and temperature than prior sample emulsifiers

  3. Compositions and process for liquid scintillation counting

    Kauffman, J.M.

    1978-01-01

    Liquid scintillation compositions which include certain polyethoxylated poly(oxypropylene) emulsifiers allow stable dispersion of aqueous or other samples merely by shaking. Preferred are mixtures of such emulsifiers, which give homogeneous, monophasic-appearing dispersions over wide ranges of temperature and aqueous sample content. Certain of these emulsifiers, without being mixed, are of particular advantage when used in analysis of samples obtained through radioimmunoassay techniques, which are extremely difficult to disperse. Certain of these emulsifiers, also without being mixed, uniformly give homogeneous, monophasic appearing aqueous counting samples over much wider ranges of aqueous sample content and temperature than prior sample emulsifiers

  4. Compositions and process for liquid scintillation counting

    1974-01-01

    Liquid scintillation counting compositions which include certain polyethoxylated poly(oxypropylene) emulsifiers allow stable dispersion of aqueous or other samples merely by shaking. Preferred are mixtures of such emulsifiers which give homogeneous monophasic-appearing dispersions over wide ranges of temperature and aqueous sample content. Certain of these emulsifiers, without being mixed, are of particular advantage when used in analysis of samples obtained through radioimmunoassay techniques which are extremely difficult to disperse. Certain of these emulsifiers, also without being mixed, uniformly give homogeneous monophasic-appearing aqueous counting samples over much wider ranges of aqueous sample content and temperature than prior sample emulsifiers

  5. Flexible carbon-based ohmic contacts for organic transistors

    Brandon, Erik (Inventor)

    2007-01-01

    The present invention relates to a system and method of organic thin-film transistors (OTFTs). More specifically, the present invention relates to employing a flexible, conductive particle-polymer composite material for ohmic contacts (i.e. drain and source).

  6. Facile fabrication of highly flexible graphene paper for photocatalytic ...

    Administrator

    potential as a carbon-based catalyst in high-performance flexible catalytic ... resultant GOs/PAA/Au composite paper was applied as a catalytic material ... Graphene, as closely packed into two-dimensional (2D) ... only display the properties of metal nanoparticles and ... the morphology and the size of AuNPs, respectively.

  7. Radio-opaque dental compositions

    Temin, S.C.

    1979-01-01

    Thorium oxide or tantalum oxide, or combinations thereof are used as the x-ray material for radio-opaque filler compositions having particular applicability in dental restorative compositions. The filler compositions contain from about 3% by weight to about 10% by weight, based on the total filler composition, of the x-ray absorbing materials and the remainder being conventional particulate glass or silica, quarts or ceramic filler material. The radio opaque filler compositions are insoluble and non-leachable in alkaline, acidic or neutral aqueous environments, are essentially non-toxic, are either essentially colorless or translucent, and are compatible with acrylic monomers and other polymerizable binder systems

  8. Special Issue: Flexible Work Arrangements.

    Olmstead, Barney, Ed.

    1996-01-01

    Section 1 contains five chapters on flexible work arrangements, self-employment, working from home, part-time professionals, job sharing, and temporary employment. Section 2 includes reviews of four books on working flexibly, concluding with a list of 23 additional readings. (SK)

  9. Measuring and Comparing Energy Flexibilities

    Valsomatzis, Emmanouil; Hose, Katja; Pedersen, Torben Bach

    2015-01-01

    induced by time and amount individually, and by their com- bination. To this end, we introduce several flexibility measures that take into account the combined effect of time and energy on flex-offer flexibility and discuss their respective pros and cons through a number of realistic examples....

  10. Sensor Technologies on Flexible Substrates

    Koehne, Jessica

    2016-01-01

    NASA Ames has developed sensor technologies on flexible substrates integrated into textiles for personalized environment monitoring and human performance evaluation. Current technologies include chemical sensing for gas leak and event monitoring and biological sensors for human health and performance monitoring. Targeted integration include next generation EVA suits and flexible habitats.

  11. Functional aspects of protein flexibility

    Teilum, Kaare; Olsen, Johan G; Kragelund, Birthe B

    2009-01-01

    this into an intuitive perception of protein function is challenging. Flexibility is of overwhelming importance for protein function, and the changes in protein structure during interactions with binding partners can be dramatic. The present review addresses protein flexibility, focusing on protein-ligand interactions...

  12. Flexible ring seal

    Abbes, Claude; Gournier, Andre; Rouaud, Christian; Villepoix, Raymond de.

    1976-01-01

    The invention concerns a flexible metal ring seal, able to ensure a perfect seal between two bearings due to the crushing and elastic deformation properties akin to similar properties in elastomers. Various designs of seal of this kind are already known, particularly a seal made of a core formed by a helical wire spring with close-wound turns and with high axial compression ratio, closed on itself and having the shape of an annulus. This wire ring is surrounded by at least one envelope having at rest the shape of a toroidal surface of which the generating circle does not close on itself. In a particular design mode, the seal in question can include, around the internal spring, two envelopes of which one in contact with the spring is composed of a low ductility elastic metal, such as mild steel or stainless steel and the other is, on the contrary, made of a malleable metal, such as copper or nickel. The first envelope evenly distributes the partial crushing of the spring, when the seal is tightened, on the second envelope which closely fits the two surfaces between which the seal operates. The stress-crushing curve characteristic of the seal comprises two separate parts, the first with a relatively sharp slope corresponds to the start of the seal compression phase, enabling at least some of these curves to reach the requisite seal threshold very quickly, then, beyond this, a second part, practically flat, where the stress is appreciably constant for a wide operating bracket [fr

  13. Flexible piezotronic strain sensor.

    Zhou, Jun; Gu, Yudong; Fei, Peng; Mai, Wenjie; Gao, Yifan; Yang, Rusen; Bao, Gang; Wang, Zhong Lin

    2008-09-01

    Strain sensors based on individual ZnO piezoelectric fine-wires (PFWs; nanowires, microwires) have been fabricated by a simple, reliable, and cost-effective technique. The electromechanical sensor device consists of a single electrically connected PFW that is placed on the outer surface of a flexible polystyrene (PS) substrate and bonded at its two ends. The entire device is fully packaged by a polydimethylsiloxane (PDMS) thin layer. The PFW has Schottky contacts at its two ends but with distinctly different barrier heights. The I- V characteristic is highly sensitive to strain mainly due to the change in Schottky barrier height (SBH), which scales linear with strain. The change in SBH is suggested owing to the strain induced band structure change and piezoelectric effect. The experimental data can be well-described by the thermionic emission-diffusion model. A gauge factor of as high as 1250 has been demonstrated, which is 25% higher than the best gauge factor demonstrated for carbon nanotubes. The strain sensor developed here has applications in strain and stress measurements in cell biology, biomedical sciences, MEMS devices, structure monitoring, and more.

  14. Orthogonal flexible Rydberg aggregates

    Leonhardt, K.; Wüster, S.; Rost, J. M.

    2016-02-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali-metal atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable nonadiabatic effects. A joint exciton-motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of nonadiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K. Leonhardt et al., Phys. Rev. Lett. 113, 223001 (2014), 10.1103/PhysRevLett.113.223001]. In this article we discuss the underlying complex dynamics in detail, characterize the switch, and derive our isotropic interaction model from a realistic anisotropic one with the addition of a magnetic bias field.

  15. SOCMA study urges flexibility

    Kirschner, E.

    1993-01-01

    In implementing the 1990 Pollution Prevention Act, regulators and legislators should hold off on cookie-cutter, numerical goal-based requirements to allow for site and process specific programs, says a study sponsored by the Synthetic Organic Chemicals Manufacturers Association (SOCMA; Washington). Companies should have that flexibility to target their resources toward those activities that reduce pollution cost effectively, says SOCMA environmental quality committee chairman Art Gillen, who is also BASF director of environmental regulatory affairs. The study - conducted by Woodward-Clyde Consultants (Denver) - examines four batch and custom chemical manufacturing films. As in the Clean Air Act, the batch processing of SOCMA-member plants should be considered in new regulations, Gillen says. For example, the study found that most wastes are from shutdowns and cleanouts, and there are frequent charges in waste streams and raw materials. Those characteristics do not lend themselves to annual reduction goals. Also, specific goals could have a wide range of costs: measures to reduce stack air emissions run from $18/lb to $1,106/lb. SOCMA says it will present the study to Congress and the Environmental Protection Agency

  16. Integrated engineering increases flexibility

    Smith, Ray

    1991-01-01

    Integrated Engineering (IE) can be used to describe the best use of increasingly rare good engineering talent in an increasingly competive world. A number of organisations are now moving towards IE without any general agreement on a precise definition. The engineering division of British Nuclear Fuels (BNFL) is one such organisation. This feature covers the reasoning behind the decision, and our experience to date. BNFL engineering division is responsible primarily for the provision of major facilities on BNFL operational sites. This provision includes feasibility, front end and detailed design, procurement, installation and commissioning. Task force working has been used for some of the large projects. But the future workload is expected to comprise many more smaller projects. At the same time, equipment is becoming more complex and the need for mutual understanding and appreciation between disciplines is increasing. To meet this increasing need for flexibility, BNFL has decided to move to the matrix structure of project management and functional departments described in the article. (Author)

  17. Flexible architecture of inducible morphological plasticity.

    Kishida, Osamu; Nishimura, Kinya

    2006-05-01

    1. Predator-induced morphological defences are produced in response to an emergent predator regime. In natural systems, prey organisms usually experience temporal shifting of the composition of the predator assemblage and of the intensity of predation risk from each predator species. Although, a repetitive morphological change in response to a sequential shift of the predator regime such as alteration of the predator species or diminution of the predation risk may be adaptive, such flexible inducible morphological defences are not ubiquitous. 2. We experimentally addressed whether a flexible inducible morphological defence is accomplished in response to serial changes in the predation regime, using a model prey species which adopt different defensive morphological phenotypes in response to different predator species. Rana pirica (Matsui) tadpoles increased body depth and tail depth against the predatory larval salamander Hynobius retardatus (Dunn); on the other hand, they only increased tail depth against the predatory larval dragonfly Aeshna nigroflava (Martin). 3. Rana pirica tadpoles with the predator-specific phenotypes were subjected to removal or exchange of the predator species. After removal of the predator species, tadpoles with each predator-specific phenotype changed their phenotype to the nondefensive basic one, suggesting that both predator-specific phenotypes are costly to maintain. After an exchange of the predator species, tadpoles with each predator-specific phenotype reciprocally, flexibly shifted their phenotype to the now more suitable predator-specific one only by modifying their body part. The partial modification can effectively reduce time and energy expenditures involved in repetitive morphological changes, and therefore suggest that the costs of the flexible morphological changes are reduced.

  18. Cyclic voltammetric study of tin hexacyanoferrate for aqueous battery applications

    Denys Gromadskyi

    2016-09-01

    Full Text Available A hybrid composite containing 65 mass % of tin hexacyanoferrate mixed with 35 mass % of carbon nanotubes has been synthesized and its electrochemical behavior as a negative electrode in alkali metal-ion batteries has been studied in 1 mol L-1 aqueous solution of sodium sulfate. The specific capacity of pure tin hexacyanoferrate is 58 mAh g-1, whereas the specific capacity normalized per total electrode mass of the composite studied reaches 34 mAh g-1. The estimated maximal specific power of an aqueous alkali-metal ion battery with a tin hexacyanoferrate electrode is ca. 3.6 kW kg-1 being comparable to characteristics of industrial electric double-layer capacitors. The maximal specific energy accumulated by this battery may reach 25.6 Wh kg-1 at least three times exceeding the specific energy for supercapacitors.

  19. Flexible electroluminescent device with inkjet-printed carbon nanotube electrodes

    Azoubel, Suzanna; Shemesh, Shay; Magdassi, Shlomo

    2012-08-01

    Carbon nanotube (CNTs) inks may provide an effective route for producing flexible electronic devices by digital printing. In this paper we report on the formulation of highly concentrated aqueous CNT inks and demonstrate the fabrication of flexible electroluminescent (EL) devices by inkjet printing combined with wet coating. We also report, for the first time, on the formation of flexible EL devices in which all the electrodes are formed by inkjet printing of low-cost multi-walled carbon nanotubes (MWCNTs). Several flexible EL devices were fabricated by using different materials for the production of back and counter electrodes: ITO/MWCNT and MWCNT/MWCNT. Transparent electrodes were obtained either by coating a thin layer of the CNTs or by inkjet printing a grid which is composed of empty cells surrounded by MWCNTs. It was found that the conductivity and transparency of the electrodes are mainly controlled by the MWCNT film thickness, and that the dominant factor in the luminance intensity is the transparency of the electrode.

  20. Voltammetric studies on composition and stabilities of complexes of tetracycline and oxytetracycline with some metal ions in aqueous medium. Voltammetrische Untersuchungen zur Zusammensetzung und Stabilitaet von Komplexen von Tetracyclin und Oxytetracyclin mit einigen Metallionen in waessrigem Medium

    Ghandour, M A; Azab, H A; Hassan, A; Ali, A M [Dept. of Chemistry, Faculty of Science, Assiut Univ., Assiut (Egypt)

    1992-01-01

    The composition and stability of complexes of tetracycline and oxytetracycline with Cu(II), Cd(II), Pb(II) and UO[sub 2](II) have been studied polarographically (direct current and differential pulse polarographic techniques) at 25[+-]0.1 deg C. Differential pulse polarographic studies have been particularly helpful in deciding the nature of metal-drug interactions at low concentrations. The reduction of Cu(II)-tetracycline has been found to be irreversible and diffusion controlled with the presence of an adsorption component. In the system uranyl(II)-tetracycline the complex formed has a stoichiometry of 1:1 and log K[sub ox] = 4.04 which is very close to that obtained by potentiometric measurements. The peak half width W[sub 1/2] of the Pb(II)-OTC system is 60-70 mV indicating that the process is reversible and two electrons are consumed. The log [beta]' is 10.30 in 0.1 mol dm[sup -3] NaClO[sub 4]. In the Cu(II)-OTC system two complexes were formed with log [beta][sub 1]' = 8.50 and log [beta][sub 2]' = 14.10. Cyclic voltammograms were recorded using a hanging dropping mercury electrode for the systems Cu(II), Cd(II), Pb(II) and UO[sub 2](II)-OTC to examine the irregularities in both peak potentials and peak currents during the polarographic investigations. (authors).

  1. Flexibility in fuel manufacturing

    Reparaz, A.; Stavig, W.E.; McLees, R.B.

    1987-01-01

    From its inception Exxon Nuclear has produced both BWR and PWR fuels. This is reflected in a product line that, to date, includes over 20 fuel designs. These range from 6x6 design at one end of the spectrum to the recently introduced 17x17 design. The benefits offered include close tailoring of the fuel design to match the customer's requirements, and the ability to rapidly introduce product changes, such as the axial blanket design, with a minimal impact on manufacturing. This flexibility places a number of demands on the manufacturing organization. Close interfaces must be established, and maintained, between the marketing, product design, manufacturing, purchasing and quality organizations, and the information flows must be immediate and accurate. Production schedules must be well planned and must be maintained or revised to reflect changing circumstances. Finally, the manufacturing facilities must be designed to allow rapid switchover between product designs with minor tooling changes and/or rerouting of product flows to alternate work stations. Among the tools used to manage the flow of information and to maintain the tight integration necessary between the various manufacturing, engineering and quality organizations is a commercially available, computerized planning and tracking system, AMAPS. A real-time production data collection system has been designed which gathers data from each production work station for use by the shop floor control module of AMAPS. Accuracy of input to the system is improved through extensive use of bar codes to gather information on the product as it moves through and between work stations. This computerized preparation of material tracing has an impact on direct manufacturing records, quality control records, nuclear material records and accounting and inventory records. This is of benefit to both Exxon Nuclear and its customers

  2. Integrated fast assembly of free-standing lithium titanate/carbon nanotube/cellulose nanofiber hybrid network film as flexible paper-electrode for lithium-ion batteries.

    Cao, Shaomei; Feng, Xin; Song, Yuanyuan; Xue, Xin; Liu, Hongjiang; Miao, Miao; Fang, Jianhui; Shi, Liyi

    2015-05-27

    A free-standing lithium titanate (Li4Ti5O12)/carbon nanotube/cellulose nanofiber hybrid network film is successfully assembled by using a pressure-controlled aqueous extrusion process, which is highly efficient and easily to scale up from the perspective of disposable and recyclable device production. This hybrid network film used as a lithium-ion battery (LIB) electrode has a dual-layer structure consisting of Li4Ti5O12/carbon nanotube/cellulose nanofiber composites (hereinafter referred to as LTO/CNT/CNF), and carbon nanotube/cellulose nanofiber composites (hereinafter referred to as CNT/CNF). In the heterogeneous fibrous network of the hybrid film, CNF serves simultaneously as building skeleton and a biosourced binder, which substitutes traditional toxic solvents and synthetic polymer binders. Of importance here is that the CNT/CNF layer is used as a lightweight current collector to replace traditional heavy metal foils, which therefore reduces the total mass of the electrode while keeping the same areal loading of active materials. The free-standing network film with high flexibility is easy to handle, and has extremely good conductivity, up to 15.0 S cm(-1). The flexible paper-electrode for LIBs shows very good high rate cycling performance, and the specific charge/discharge capacity values are up to 142 mAh g(-1) even at a current rate of 10 C. On the basis of the mild condition and fast assembly process, a CNF template fulfills multiple functions in the fabrication of paper-electrode for LIBs, which would offer an ever increasing potential for high energy density, low cost, and environmentally friendly flexible electronics.

  3. Incentivizing Flexibility in System Operations

    Milligan, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bloom, Aaron P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Townsend, Aaron [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ela, Erik [Electric Power Research Institute; Botterud, Audun [Argonne National Laboratory; Levin, Todd [Argonne National Laboratory

    2018-02-15

    Defining flexibility has been a challenge that a number of industry members and researchers have attempted to address in recent years. With increased variability and uncertainty of variable generation (VG), the resources on the system will have to be more flexible to adjust output, so that power output ranges, power ramp rates, and energy duration sustainability are sufficient to meet the needs of balancing supply with demand at various operational timescales. This chapter discusses whether existing market designs provide adequate incentives for resources to offer their flexibility into the market to meet the increased levels of variability and uncertainty introduced by VG in the short-term operational time frame. It presents a definition of flexibility and discusses how increased levels of VG require increased needs for flexibility on power systems. Following this introductory material, the chapter examines how existing market designs ensure that resources have the right incentives to provide increased flexibility, and then discusses a number of emerging market design elements that impact flexibility incentives.

  4. Flexible Supercapacitors Based on Polyaniline Arrays Coated Graphene Aerogel Electrodes.

    Yang, Yu; Xi, Yunlong; Li, Junzhi; Wei, Guodong; Klyui, N I; Han, Wei

    2017-12-01

    Flexible supercapacitors(SCs) made by reduced graphene oxide (rGO)-based aerogel usually suffer from the low energy density, short cycle life and bad flexibility. In this study, a new, synthetic strategy was developed for enhancing the electrochemical performances of rGO aerogel-based supercapacitor via electrodeposition polyaniline arrays on the prepared ultralight rGO aerogel. The novel hybrid composites with coated polyaniline (PANI) arrays growing on the rGO surface can take full advantage of the rich open-pore and excellent conductivity of the crosslinking framework structure of 3D rGO aerogel and high capacitance contribution from the PANI. The obtained hybrid composites exhibit excellent electrochemical performance with a specific capacitance of 432 F g -1 at the current density of 1 A g -1 , robust cycling stability to maintain 85% after 10,000 charge/discharge cycles and high energy density of 25 W h kg -1 . Furthermore, the flexible all-solid-state supercapacitor have superior flexibility and outstanding stability under different bending states from the straight state to the 90° status. The high-performance flexible all-solid-state SCs together with the lighting tests demonstrate it possible for applications in portable electronics.

  5. Aggregating and Disaggregating Flexibility Objects

    Siksnys, Laurynas; Valsomatzis, Emmanouil; Hose, Katja

    2015-01-01

    In many scientific and commercial domains we encounter flexibility objects, i.e., objects with explicit flexibilities in a time and an amount dimension (e.g., energy or product amount). Applications of flexibility objects require novel and efficient techniques capable of handling large amounts...... and aiming at energy balancing during aggregation. In more detail, this paper considers the complete life cycle of flex-objects: aggregation, disaggregation, associated requirements, efficient incremental computation, and balance aggregation techniques. Extensive experiments based on real-world data from...

  6. Aqueous-salt system containing ytterbium nitrate and pyridine nitrate

    Zhuravlev, E.F.; Khisaeva, D.A.; Izmajlova, L.V.

    1983-01-01

    Cross-section method has been used to study solubility in ternary aqueous-salt system Yb(NO 3 ) 3 -C 5 H 5 NxHNO 3 -H 2 0 at 25 and 50 deg C. It is established that the system is characterized by chemical interaction. Congruently soluble compound of Yb(NO 3 ) 3 x2[C 5 H 5 NxHNO 3 ] composition is discovered in the system. Composition of the compound is confirmed by chemical analysis; its infrared spectra are studied. Interplanar distances are determined; derivatogram of the compound is given. The results of the works are compared with analogous investigations of another rare earth nitrates

  7. Flexible Thermoelectric Generators on Silicon Fabric

    Sevilla, Galo T.

    2012-01-01

    In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart

  8. Flexibility of trunnion piping elbows

    Lewis, G.D.; Chao, Y.J.

    1987-01-01

    Flexibility factors and stress indices for piping component such as straight pipe, elbows, butt-welding tees, branch connections, and butt-welding reducers are contained in the code, but many of the less common piping components, like the trunnion elbow, do not have flexibility factors or stress indices defined. The purpose of this paper is to identify the in-plane and out-of-plane flexibility factors in accordance with code procedures for welded trunnions attached to the tangent centerlines of long radius elbows. This work utilized the finite element method as applicable to plates and shells for calculating the relative rotations of the trunnion elbow-ends for in-plane and out-of-plane elbow moment loadings. These rotations are used to derive the corresponding in-plane and out-of-plane flexibility factors. (orig./GL)

  9. Distributed flexibility in inertial swimmers

    Floryan, Daniel; Rowley, Clarence W.; Smits, Alexander J.

    2017-11-01

    To achieve fast and efficient swimming, the flexibility of the propulsive surfaces is an important feature. To better understand the effects of distributed flexibility (either through inhomogeneous material properties, varying geometry, or both) we consider the coupled solid and fluid mechanics of the problem. Here, we develop a simplified model of a flexible swimmer, using Euler-Bernoulli theory to describe the solid, Theodorsen's theory to describe the fluid, and a Blasius boundary layer to incorporate viscous effects. Our primary aims are to understand how distributed flexibility affects the thrust production and efficiency of a swimmer with imposed motion at its leading edge. In particular, we examine the modal shapes of the swimmer to gain physical insight into the observed trends. Supported under ONR MURI Grant N00014-14-1-0533, Program Manager Robert Brizzolara.

  10. Highly reversible zinc metal anode for aqueous batteries

    Wang, Fei; Borodin, Oleg; Gao, Tao; Fan, Xiulin; Sun, Wei; Han, Fudong; Faraone, Antonio; Dura, Joseph A.; Xu, Kang; Wang, Chunsheng

    2018-06-01

    Metallic zinc (Zn) has been regarded as an ideal anode material for aqueous batteries because of its high theoretical capacity (820 mA h g-1), low potential (-0.762 V versus the standard hydrogen electrode), high abundance, low toxicity and intrinsic safety. However, aqueous Zn chemistry persistently suffers from irreversibility issues, as exemplified by its low coulombic efficiency (CE) and dendrite growth during plating/ stripping, and sustained water consumption. In this work, we demonstrate that an aqueous electrolyte based on Zn and lithium salts at high concentrations is a very effective way to address these issues. This unique electrolyte not only enables dendrite-free Zn plating/stripping at nearly 100% CE, but also retains water in the open atmosphere, which makes hermetic cell configurations optional. These merits bring unprecedented flexibility and reversibility to Zn batteries using either LiMn2O4 or O2 cathodes—the former deliver 180 W h kg-1 while retaining 80% capacity for >4,000 cycles, and the latter deliver 300 W h kg-1 (1,000 W h kg-1 based on the cathode) for >200 cycles.

  11. Determinants of flexible work arrangements

    Sarbu, Miruna

    2014-01-01

    Flexible work arrangements such as allowing employees to work at home are used in firms, especially since information and communication technologies have become so widespread. Using individual-level data from 10,884 German employees, this paper analyses the determinants of working at home as a form of flexible work arrangements. The analysis is based on descriptive analyses and a discrete choice model using a probit estimation approach. The results reveal that men have a higher...

  12. Workplace flexibility across the lifespan

    Bal, Pieter; Jansen, Paul G W

    2016-01-01

    As demographic changes impact the workplace, governments, organizations and workers arelooking for ways to sustain optimal working lives at higher ages. Workplace flexibility has beenintroduced as a potential way workers can have more satisfying working lives until theirretirement ages. This paper presents a critical review of the literature on workplace flexibilityacross the lifespan. It discusses how flexibility has been conceptualized across differentdisciplines, and postulates a definitio...

  13. Flexible packaging for PV modules

    Dhere, Neelkanth G.

    2008-08-01

    Economic, flexible packages that provide needed level of protection to organic and some other PV cells over >25-years have not yet been developed. However, flexible packaging is essential in niche large-scale applications. Typical configuration used in flexible photovoltaic (PV) module packaging is transparent frontsheet/encapsulant/PV cells/flexible substrate. Besides flexibility of various components, the solder bonds should also be flexible and resistant to fatigue due to cyclic loading. Flexible front sheets should provide optical transparency, mechanical protection, scratch resistance, dielectric isolation, water resistance, UV stability and adhesion to encapsulant. Examples are Tefzel, Tedlar and Silicone. Dirt can get embedded in soft layers such as silicone and obscure light. Water vapor transmittance rate (WVTR) of polymer films used in the food packaging industry as moisture barriers are ~0.05 g/(m2.day) under ambient conditions. In comparison, light emitting diodes employ packaging components that have WVTR of ~10-6 g/(m2.day). WVTR of polymer sheets can be improved by coating them with dense inorganic/organic multilayers. Ethylene vinyl acetate, an amorphous copolymer used predominantly by the PV industry has very high O2 and H2O diffusivity. Quaternary carbon chains (such as acetate) in a polymer lead to cleavage and loss of adhesional strength at relatively low exposures. Reactivity of PV module components increases in presence of O2 and H2O. Adhesional strength degrades due to the breakdown of structure of polymer by reactive, free radicals formed by high-energy radiation. Free radical formation in polymers is reduced when the aromatic rings are attached at regular intervals. This paper will review flexible packaging for PV modules.

  14. Flexible forms of working hours

    Knapp, Viktor

    2017-01-01

    66 Abstract - Flexible forms of working hours This diploma thesis deals with the flexible forms of working hours and its goal is to describe this issue in intelligible and comprehensive way. It is being very interesting and current theme which is to a great extent not subject to direct legal regulations and provides its contracting parties with a big amount of freedom of contract. This fact assists in bigger flexibilization of labour market and represents a significant instrument in the fight...

  15. Superconducting composite for magnetic bearings

    Rigney, T.K. II.

    1995-01-01

    A composite includes granules of Type II superconducting material and granules of rare-earth permanent magnets that are distributed in a binder. The composite is a two-phase structure that combines the properties of the superconductor and magnets with the flexibility and toughness of a polymeric material. A bearing made from this composite has the load capacity and stiffness of a permanent magnet bearing with added stability from a Type II superconducting material. 7 figs

  16. Developmental constraints on behavioural flexibility.

    Holekamp, Kay E; Swanson, Eli M; Van Meter, Page E

    2013-05-19

    We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.

  17. Free-standing and mechanically flexible mats consisting of electrospun carbon nanofibers made from a natural product of alkali lignin as binder-free electrodes for high-performance supercapacitors

    Lai, Chuilin; Zhou, Zhengping; Zhang, Lifeng; Wang, Xiaoxu; Zhou, Qixin; Zhao, Yong; Wang, Yechun; Wu, Xiang-Fa; Zhu, Zhengtao; Fong, Hao

    2014-02-01

    Mechanically flexible mats consisting of electrospun carbon nanofibers (ECNFs) were prepared by first electrospinning aqueous mixtures containing a natural product of alkali lignin together with polyvinyl alcohol (PVA) into composite nanofiber mats followed by stabilization in air and carbonization in an inert environment. Morphological and structural properties, as well as specific surface area, total pore volume, average pore size, and pore size distribution, of the lignin-based ECNF mats were characterized; and their electrochemical performances (i.e., capacitive behaviors) were evaluated by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The lignin-based ECNF mats exhibited outstanding performance as free-standing and/or binder-free electrodes of supercapacitors. For example, the ECNFs made from the composite nanofibers with mass ratio of lignin/PVA being 70/30 (i.e., ECNFs (70/30)) had the average diameter of ∼100 nm and the Brunauer-Emmett-Teller (BET) specific surface area of ∼583 m2 g-1. The gravimetric capacitance of ECNFs (70/30) electrode in 6 M KOH aqueous electrolyte exhibited 64 F g-1 at current density of 400 mA g-1 and 50 F g-1 at 2000 mA g-1. The ECNFs (70/30) electrode also exhibited excellent cycling durability/stability, and the gravimetric capacitance merely reduced by ∼10% after 6000 cycles of charge/discharge.

  18. Recent results on aqueous electrolyte cells

    Wessells, Colin; Huggins, Robert A.; Cui, Yi

    2011-01-01

    The improved safety of aqueous electrolytes makes aqueous lithium-ion batteries an attractive alternative to commercial cells utilizing flammable and expensive organic electrolytes. Two important issues relating to their use have been addressed

  19. Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water

    Mohamed, Alaa [Department of Materials and NanoPhysics, Royal Institute of Technology (KTH), 16440 Kista, Stockholm (Sweden); Mechanical Design and Production Engineering Department, Cairo University, 12613 Giza (Egypt); Production Engineering and Printing Technology Department, Akhbar El Yom Academy, 12655 Giza (Egypt); El-Sayed, Ramy [Experimental Cancer Medicine, KFC, Novum, Department of laboratory Medicine, Karolinska Institute, 14186 Stockholm (Sweden); Osman, T.A. [Mechanical Design and Production Engineering Department, Cairo University, 12613 Giza (Egypt); Toprak, M.S.; Muhammed, M. [Department of Materials and NanoPhysics, Royal Institute of Technology (KTH), 16440 Kista, Stockholm (Sweden); Uheida, A., E-mail: salam@kth.se [Department of Materials and NanoPhysics, Royal Institute of Technology (KTH), 16440 Kista, Stockholm (Sweden)

    2016-02-15

    In this study highly efficient photocatalyst based on composite nanofibers containing polyacrylonitrile (PAN), carbon nanotubes (CNT), and surface functionalized TiO{sub 2} nanoparticles was developed. The composite nanofibers were fabricated using electrospinning technique followed by chemical crosslinking. The surface modification and morphology changes of the fabricated composite nanofibers were examined through SEM, TEM, and FTIR analysis. The photocatalytic performance of the composite nanofibers for the degradation of model molecules, methylene blue and indigo carmine, under UV irradiation in aqueous solutions was investigated. The results demonstrated that high photodegradation efficiency was obtained in a short time and at low power intensity compared to other reported studies. The effective factors on the degradation of the dyes, such as the amount of catalyst, solution pH and irradiation time were investigated. The experimental kinetic data were fitted using pseudo-first order model. The effect of the composite nanofibers as individual components on the degradation efficiency of MB and IC was evaluated in order to understand the overall photodegradation mechanism. The results obtained showed that all the components possess significant effect on the photodegradation activity of the composite nanofibers. The stability studies demonstrated that the photodegradation efficiency can remain constant at the level of 99% after five consecutive cycles. - Highlights: • Develop effective photocatalyst based on PAN–CNT/TiO{sub 2}–NH{sub 2} composite nanofibers. • High photodegradation efficiency and fast kinetics was obtained. • Regeneration of the composite nanofibers allowed the reuse of these material. • Mechanism of the photocatalytic degradation was proposed. • The flexibility of the composite nanofibers allows use in a continuous operation mode.

  20. Composite nanofibers for highly efficient photocatalytic degradation of organic dyes from contaminated water

    Mohamed, Alaa; El-Sayed, Ramy; Osman, T.A.; Toprak, M.S.; Muhammed, M.; Uheida, A.

    2016-01-01

    In this study highly efficient photocatalyst based on composite nanofibers containing polyacrylonitrile (PAN), carbon nanotubes (CNT), and surface functionalized TiO 2 nanoparticles was developed. The composite nanofibers were fabricated using electrospinning technique followed by chemical crosslinking. The surface modification and morphology changes of the fabricated composite nanofibers were examined through SEM, TEM, and FTIR analysis. The photocatalytic performance of the composite nanofibers for the degradation of model molecules, methylene blue and indigo carmine, under UV irradiation in aqueous solutions was investigated. The results demonstrated that high photodegradation efficiency was obtained in a short time and at low power intensity compared to other reported studies. The effective factors on the degradation of the dyes, such as the amount of catalyst, solution pH and irradiation time were investigated. The experimental kinetic data were fitted using pseudo-first order model. The effect of the composite nanofibers as individual components on the degradation efficiency of MB and IC was evaluated in order to understand the overall photodegradation mechanism. The results obtained showed that all the components possess significant effect on the photodegradation activity of the composite nanofibers. The stability studies demonstrated that the photodegradation efficiency can remain constant at the level of 99% after five consecutive cycles. - Highlights: • Develop effective photocatalyst based on PAN–CNT/TiO 2 –NH 2 composite nanofibers. • High photodegradation efficiency and fast kinetics was obtained. • Regeneration of the composite nanofibers allowed the reuse of these material. • Mechanism of the photocatalytic degradation was proposed. • The flexibility of the composite nanofibers allows use in a continuous operation mode.