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Sample records for nanoparticles wet chemical

  1. Lecithin-based wet chemical precipitation of hydroxyapatite nanoparticles.

    Science.gov (United States)

    Michał, Wojasiński; Ewa, Duszyńska; Tomasz, Ciach

    Hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 nanoparticles have been successfully synthesized by the wet chemical precipitation method at 60 °C in the presence of biocompatible natural surfactant-lecithin. The composition and morphology of nanoparticles of hydroxyapatite synthesized with lecithin (nHAp-PC) was studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Size distribution for nanoparticles was measured by nanoparticle tracking analysis in NanoSight system. We discuss in details influence of lecithin concentration in reaction system on nHAp-PC morphology, as well as on size distributions and suspendability of nanoparticles. Product exhibits crystalline structure and chemical composition of hydroxyapatite, with visible traces of lecithin. Difference in surfactant amounts results in changes in particles morphology and their average size.

  2. Characterization of silver nanoparticles prepared by wet chemical ...

    African Journals Online (AJOL)

    Results: The silver nanoparticles formed were spherical in shape with mean size of 10.3 nm. The ... antibacterial activity against various strains of bacteria. Keywords: Wet ..... Fang J, Zhong C, Mu R. The study of deposited silver particulate ...

  3. PEG capped CaS nanoparticles synthesized by wet chemical co-precipitation method

    Science.gov (United States)

    Rekha, S.; Anila, E. I.

    2018-04-01

    Calcium sulfide (CaS) nanoparticles capped with polyethyleneglycol (PEG) were synthesized using wet chemical co-precipitation method. The structural and optical properties of the prepared sample were studied by X-ray diffractogram (XRD), transmission electron microscopy (TEM), diffuse reflectance spectrum (DRS) and photoluminescence (PL) spectrum. The structure of CaS nanoparticles is cubic as demonstrated by the X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) analysis. TEMimage revealed the spherical morphology of the particles with diameter in the range 15-20 nm. The optical band gap of the prepared sample was determined from the DRS and its value was found to be 4.1 eV. The PL studies showed that the relative intensity of the PEG capped CaS nanoparticles was higher than that of uncapped CaS nanoparticles. The presence of various functional groups in the capped samples were examined by Fourier Transform Infrared (FTIR) spectroscopy.

  4. Bottom-Up, Wet Chemical Technique for the Continuous Synthesis of Inorganic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Annika Betke

    2014-01-01

    Full Text Available Continuous wet chemical approaches for the production of inorganic nanoparticles are important for large scale production of nanoparticles. Here we describe a bottom-up, wet chemical method applying a microjet reactor. This technique allows the separation between nucleation and growth in a continuous reactor environment. Zinc oxide (ZnO, magnetite (Fe3O4, as well as brushite (CaHPO4·2H2O, particles with a small particle size distribution can be obtained continuously by using the rapid mixing of two precursor solutions and the fast removal of the nuclei from the reaction environment. The final particles were characterized by FT-IR, TGA, DLS, XRD and SEM techniques. Systematic studies on the influence of the different process parameters, such as flow rate and process temperature, show that the particle size can be influenced. Zinc oxide was obtained with particle sizes between 44 nm and 102 nm. The obtained magnetite particles have particle sizes in the range of 46 nm to 132 nm. Brushite behaves differently; the obtained particles were shaped like small plates with edge lengths between 100 nm and 500 nm.

  5. Synthesis of CuS nanoparticles by a wet chemical route and their photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Mou; Mathews, N. R. [Universidad Nacional Autónoma de México, Instituto de Energías Renovables (Mexico); Sanchez-Mora, E.; Pal, U. [Instituto de Física, BUAP (Mexico); Paraguay-Delgado, F. [Centro de Investigación en Materiales Avanzados (CIMAV), Departamento de Materiales Nanoestructurados (Mexico); Mathew, X., E-mail: xm@ier.unam.mx [Universidad Nacional Autónoma de México, Instituto de Energías Renovables (Mexico)

    2015-07-15

    CuS nanoparticles (NPs) of few nanometers in size were prepared by a wet chemical method. The structural, compositional, and optical properties of the NPs were characterized by X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, micro Raman and Fourier transform infrared spectroscopy, N{sub 2} adsorption–desorption isotherms, and UV–Vis diffuse reflectance spectroscopy. The XRD pattern proved the presence of hexagonal phase of CuS particles which was further supported by Raman spectrum. The estimated band gap energy of 2.05 eV for the slightly sulfur-rich CuS NPs is relatively larger than that of bulk CuS (1.85 eV), indicating the small size effect. As-prepared NPs showed excellent photocatalytic activity for the degradation of methylene blue (MB) under visible light. The surface-bound OH{sup −} ions at the CuS nanostructures help adsorb MB molecules facilitating their degradation process under visible light illumination. The studies presented in this paper suggest that the synthesized CuS NPs are promising, efficient, stable, and visible-light-sensitive photocatalyst for the remediation of wastewater polluted by chemically stable azo dyes such as MB.

  6. Fabrication of Cu{sub 2}S nanoneedles by self-assembly of nanoparticles via simple wet chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Kumarakuru, Haridas, E-mail: haridas.kumarakuru@nmmu.ac.za; Coombes, Matthew J.; Neethling, Johannes H.; Westraadt, Johan E.

    2014-03-15

    Highlights: • An inexpensive wet chemical method was used at room temperature to grow Cu{sub 2}S. • Growth of Cu{sub 2}S nanostructures influences by the Cl{sup −} ion concentration. • Thioglycerol and Cl{sup −} ions are used as a blend capping agents. • Cu{sub 2}S nanoneedles were formed via self-assembly of nanoparticles. • We can propose a growth model for Cu{sub 2}S nanoneedles based on our observations. -- Abstract: Cu{sub 2}S nanoneedles, fabricated by self-assembly of Cu{sub 2}S nanoparticles via wet chemical method are investigated. Crystallinity and surface morphologies of the as-grown needles are examined using X-ray diffraction and scanning and transmission electron microscopy. It is observed that the nanoparticle formation is controlled by the blend concentration of capping agents, thioglycerol, added during the synthesis and the Cl{sup −} ions delivered by the CuCl source. The likely reasons for the elongated structure of the nanoparticle self-assembly are also discussed.

  7. Size- and Shape-Dependent Antibacterial Studies of Silver Nanoparticles Synthesized by Wet Chemical Routes

    Directory of Open Access Journals (Sweden)

    Muhammad Akram Raza

    2016-04-01

    Full Text Available Silver nanoparticles (AgNPs of different shapes and sizes were prepared by solution-based chemical reduction routes. Silver nitrate was used as a precursor, tri-sodium citrate (TSC and sodium borohydride as reducing agents, while polyvinylpyrrolidone (PVP was used as a stabilizing agent. The morphology, size, and structural properties of obtained nanoparticles were characterized by scanning electron microscopy (SEM, UV-visible spectroscopy (UV-VIS, and X-ray diffraction (XRD techniques. Spherical AgNPs, as depicted by SEM, were found to have diameters in the range of 15 to 90 nm while lengths of the edges of the triangular particles were about 150 nm. The characteristic surface plasmon resonance (SPR peaks of different spherical silver colloids occurring in the wavelength range of 397 to 504 nm, whereas triangular particles showed two peaks, first at 392 nm and second at 789 nm as measured by UV-VIS. The XRD spectra of the prepared samples indicated the face-centered cubic crystalline structure of metallic AgNPs. The in vitro antibacterial properties of all synthesized AgNPs against two types of Gram-negative bacteria, Pseudomonas aeruginosa and Escherichia coli were examined by Kirby–Bauer disk diffusion susceptibility method. It was noticed that the smallest-sized spherical AgNPs demonstrated a better antibacterial activity against both bacterial strains as compared to the triangular and larger spherical shaped AgNPs.

  8. Hysteresis losses in iron oxide nanoparticles prepared by glass crystallization or wet chemical precipitation

    International Nuclear Information System (INIS)

    Mueller, Robert; Dutz, Silvio; Hergt, Rudolf; Schmidt, Christopher; Steinmetz, Hanna; Zeisberger, Matthias; Gawalek, Wolfgang

    2007-01-01

    Ferrofluids were prepared from glass crystallized as well as wet precipitated iron oxide particles. Comparing hysteresis losses versus applied field amplitude from particles in immobilized state (powder) and in fluid state (ferrofluid) shows in some cases anomalous large losses at low magnetic fields. The influence of texture on the losses was investigated

  9. Influence of citric acid on SnO2 nanoparticles synthesized by wet chemical processes

    CSIR Research Space (South Africa)

    Sikhwivhilu, LM

    2010-10-01

    Full Text Available influences the particle size and the BET specific surface area. The XRD analysis revealed that nanoparticles were phase pure and that all materials exhibited a tetragonal rutile structure of SnO2. Characterisation of the materials was carried out using...

  10. Morphology, thermoelectric properties and wet-chemical doping of laser-sintered germanium nanoparticles

    International Nuclear Information System (INIS)

    Stoib, Benedikt; Langmann, Tim; Matich, Sonja; Sachsenhauser, Matthias; Stutzmann, Martin; Brandt, Martin S.; Petermann, Nils; Wiggers, Hartmut

    2013-01-01

    Porous, highly doped semiconductors are potential candidates for thermoelectric energy conversion elements. We report on the fabrication of thin films of Ge via short-pulse laser-sintering of Ge nanoparticles (NPs) in vacuum and study the macroporous morphology of the samples by secondary electron microscopy (SEM) imaging. The temperature dependence of the electrical conductivity and the Seebeck coefficient of undoped Ge is discussed in conjunction with the formation of a defect band near the valence band. We further introduce a versatile method of doping the resulting films with a variety of common dopant elements in group-IV semiconductors by using a liquid containing the dopant atoms. This method is fully compatible with laser-direct writing and suited to fabricate small scale thermoelectric generators. The incorporation of the dopants is verified by X-ray photoelectron spectroscopy (XPS) and their electrical activation is studied by conductivity and thermopower measurements. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. The Synthesis of Anatase Nanoparticles and the Preparation of Photocatalytically Active Coatings Based on Wet Chemical Methods for Self-Cleaning Applications

    Directory of Open Access Journals (Sweden)

    Dejan Verhovšek

    2012-01-01

    Full Text Available We report on an improved sol-gel method for the production of highly photocatalytic titanium dioxide (TiO2 anatase nanoparticles which can provide appropriate control over the final characteristics of the nanoparticles, such as particle size, crystallinity, crystal structure, morphology, and also the degree of agglomeration. The synthesized anatase nanoparticles were characterized using various techniques, such as X-ray powder diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM, and were tested in coatings for self-cleaning glass and ceramic surfaces. The coatings were prepared using a soft chemistry route and are completely transparent to visible light and exhibit a high photocatalytic effect, which was determined by contact-angle measurements. Finally, it is worth mentioning that both the sol-gel synthesis method and the coating-preparation method are based on a wet chemical process, thus presenting no risk of handling the TiO2 anatase nanoparticles in their potentially hazardous powder form at any stage of our development. Low-price, easy-to-handle, and nontoxic materials were used. Therefore, our work represents an important contribution to the development of TiO2 anatase nanoparticle coatings that provide a high photocatalytic effect and can thus be used for numerous applications.

  12. Parametric optimisation of core–shell ZnS:Mn/ZnS nanoparticles prepared by ultrasound-controlled wet chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Suranjan, E-mail: suranjansen@iitb.ac.in [National Centre for Photovoltaic Research and Education (NCPRE), IIT Bombay, Powai, Mumbai 400076 (India); Department of Energy Science and Engineering, IIT Bombay, Powai, Mumbai 400076 (India); Solanki, Chetan Singh, E-mail: chetanss@iitb.ac.in [National Centre for Photovoltaic Research and Education (NCPRE), IIT Bombay, Powai, Mumbai 400076 (India); Department of Energy Science and Engineering, IIT Bombay, Powai, Mumbai 400076 (India); Sharma, Pratibha, E-mail: pratibha_sharma@iitb.ac.in [National Centre for Photovoltaic Research and Education (NCPRE), IIT Bombay, Powai, Mumbai 400076 (India); Department of Energy Science and Engineering, IIT Bombay, Powai, Mumbai 400076 (India)

    2014-01-15

    Core–shell type manganese-doped zinc sulphide nanoparticles ZnS:Mn/ZnS, showing strong absorption of ultraviolet light in the 280–450 nm range and emitting orange-yellow light close to 600 nm, were synthesised for eventual deployment as wavelength down-shifters for solar cells. While most syntheses described in literature employed long reaction times and high reaction/annealing temperatures in excess of 100 °C, this work presents a facile low-temperature wet chemical route. Key synthesis parameters – including zinc to sulphur ratio, manganese doping percentage, reaction sequence and ultrasonication time – were optimised systematically to achieve optimum orange emission intensity. Nanoparticles with average size ∼2.3 nm and showing bright orange emission under UV excitation were ultimately achieved. Various characterisation techniques, namely HRTEM, XRD, ICP, ESR, UV–visible absorption spectrometry and fluorescence spectroscopy, were used to probe the nature of the sample. -- Highlights: • Shell formation achieved by ultrasonic decomposition of zinc–thiourea complex. • Optimal zinc to sulphur ratio in reaction mix was found to be 1:1.2. • Optimal manganese doping percentage was found to be 5.8%. • Addition of cationic precursors to anionic precursors proved to be favourable. • Ultrasonication times exceeding 15 min were detrimental to emission intensity.

  13. The usability of ark clam shell (Anadara granosa) as calcium precursor to produce hydroxyapatite nanoparticle via wet chemical precipitate method in various sintering temperature.

    Science.gov (United States)

    Khiri, Mohammad Zulhasif Ahmad; Matori, Khamirul Amin; Zainuddin, Norhazlin; Abdullah, Che Azurahanim Che; Alassan, Zarifah Nadakkavil; Baharuddin, Nur Fadilah; Zaid, Mohd Hafiz Mohd

    2016-01-01

    This paper reported the uses of ark clam shell calcium precursor in order to form hydroxyapatite (HA) via the wet chemical precipitation method. The main objective of this research is to acquire better understanding regarding the effect of sintering temperature in the fabrication of HA. Throughout experiment, the ratio of Ca:P were constantly controlled, between 1.67 and 2.00. The formation of HA at these ratio was confirmed by means of energy-dispersive X-ray spectroscopy analysis. In addition, the effect of sintering temperature on the formation of HA was observed using X-ray diffraction analysis, while the structural and morphology was determined by means of field emission scanning electron microscopy. The formation of HA nanoparticle was recorded (~35-69 nm) in the form of as-synthesize HA powder. The bonding compound appeared in the formation of HA was carried out using Fourier transform infrared spectroscopy such as biomaterials that are expected to find potential applications in orthopedic and biomedical industries .

  14. Synthesis of BaTiO3 nanoparticles from TiO2-coated BaCO3 particles derived using a wet-chemical method

    Directory of Open Access Journals (Sweden)

    Yuuki Mochizuki

    2014-03-01

    Full Text Available BaCO3 particles coated with amorphous TiO2 precursor are prepared by a wet chemical method to produce BaTiO3 nanoparticles at low temperatures. Subsequently, we investigate the formation behavior of BaTiO3 particles and the particle growth behavior when the precursor is subjected to heat treatment. The state of the amorphous TiO2 coating on the surface of BaCO3 particles depends on the concentration of NH4HCO3, and the optimum concentration is found to be in the range 0.5–1.0 M. Thermogravimetric curves of the BaCO3 particles coated with the TiO2 precursor, prepared from BaCO3 particles of various sizes, show BaTiO3 formation occurring mainly at 550–650 °C in the case of fine BaCO3 particles. However, as evidenced from the curves, the temperature of formation of BaTiO3 shifts to higher values with an increase in the size of the BaCO3 particles. The average particle size of single phase BaTiO3 at heat-treatment temperature of 650–900 °C is observed to be in the range 60–250 nm.

  15. Wet chemical synthesis of soluble gold nanogaps

    DEFF Research Database (Denmark)

    Jain, Titoo; Tang, Qingxin; Bjørnholm, Thomas

    2014-01-01

    NRs) in aqueous solution. Through controlled end-to-end assembly of the AuNRs into dimers or chains, facilitated via target molecules, they can be used as electrical contacts. In this way, the preparation of AuNR-molecule-AuNR junctions by wet chemical methods may afford a large number of identical devices...... with little variation in the interface between molecule and electrode (AuNR). In this Account, we highlight recent progress in using chemically synthesized AuNRs as building blocks for molecular electronic applications. We outline the general synthesis and properties of AuNRs and describe the aqueous growth...... in the nanogaps lets us spectroscopically characterize the molecules via surface-enhanced Raman scattering. We discuss the incorporation of oligopeptides functionalized with acetylene units having uniquely identifiable vibrational modes. This acetylene moiety allows chemical reactions to be performed in the gaps...

  16. Wetting kinetics of water nano-droplet containing non-surfactant nanoparticles: A molecular dynamics study

    International Nuclear Information System (INIS)

    Lu, Gui; Hu, Han; Sun, Ying; Duan, Yuanyuan

    2013-01-01

    In this Letter, dynamic wetting of water nano-droplets containing non-surfactant gold nanoparticles on a gold substrate is examined via molecular dynamics simulations. The results show that the addition of non-surfactant nanoparticles hinders the nano-second droplet wetting process, attributed to the increases in both surface tension of the nanofluid and friction between nanofluid and substrate. The droplet wetting kinetics decreases with increasing nanoparticle loading and water-particle interaction energy. The observed wetting suppression and the absence of nanoparticle ordering near the contact line of nano-sized droplets differ from the wetting behaviors reported from nanofluid droplets of micron size or larger

  17. Wet-etch sequence optimisation incorporating time dependent chemical maintenance

    NARCIS (Netherlands)

    Kruif, B.J. de

    2015-01-01

    Wafer fabrication is the major cost contributor in semiconductor manufacturing. One of the steps in the fabrication is the removal of exposed layers in an automatic wet-etch station with chemicals. In time, these chemicals get polluted and their effectiveness decreases. Therefore, the chemicals in

  18. Simulation of convection-driven wet-chemical etching

    NARCIS (Netherlands)

    Driesen, C.H.

    1999-01-01

    In a wet-chemical etching process, the resulting etched shape is smaller than the originally designed shape at the mask. This is caused by the fact that, as soon as material next to the mask is dissolved, material under the mask will be dissolved too. This is the so-called undercut effect. During an

  19. Simulation of convection-driven wet-chemical etching

    NARCIS (Netherlands)

    Driesen, C.H.

    1999-01-01

    a wet-chemical etching process, the resulting etched shape is smaller than the originally designed shape at the mask. This is caused by the fact that, as soon as material next to the mask is dissolved, material under the mask will be dissolved too. This is the so-called undercut effect. During an

  20. Physical chemistry of wet chemical anisotropic etching of silicon

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    1995-01-01

    In this paper we explain a view to understand the anisotropy of the etching of silicon in certain wet chemical agents (such as KOH). The starting point is the assumption that the [Left angle bracket]111[Right Angle Bracket] face of silicon is a flat face, the etch rate of which is then governed by a

  1. Activation of aluminum as an effective reducing agent by pitting corrosion for wet-chemical synthesis.

    Science.gov (United States)

    Li, Wei; Cochell, Thomas; Manthiram, Arumugam

    2013-01-01

    Metallic aluminum (Al) is of interest as a reducing agent because of its low standard reduction potential. However, its surface is invariably covered with a dense aluminum oxide film, which prevents its effective use as a reducing agent in wet-chemical synthesis. Pitting corrosion, known as an undesired reaction destroying Al and is enhanced by anions such as F⁻, Cl⁻, and Br⁻ in aqueous solutions, is applied here for the first time to activate Al as a reducing agent for wet-chemical synthesis of a diverse array of metals and alloys. Specifically, we demonstrate the synthesis of highly dispersed palladium nanoparticles on carbon black with stabilizers and the intermetallic Cu₂Sb/C, which are promising candidates, respectively, for fuel cell catalysts and lithium-ion battery anodes. Atomic hydrogen, an intermediate during the pitting corrosion of Al in protonic solvents (e.g., water and ethylene glycol), is validated as the actual reducing agent.

  2. Calcium phosphate bioceramics prepared from wet chemically precipitated powders

    Directory of Open Access Journals (Sweden)

    Kristine Salma

    2010-03-01

    Full Text Available In this work calcium phosphates were synthesized by modified wet chemical precipitation route. Contrary to the conventional chemical precipitation route calcium hydroxide was homogenized with planetary mill. Milling calcium oxide and water in planetary ball mill as a first step of synthesis provides a highly dispersed calcium hydroxide suspension. The aim of this work was to study the influence of main processing parameters of wet chemical precipitation synthesis product and to control the morphology, phase and functional group composition and, consequently, thermal stability and microstructure of calcium phosphate bioceramics after thermal treatment. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions after thermal processing (hydroxyapatite [HAp], β-tricalcium phosphate [β-TCP] and HAp/β-TCP by modified wet-chemical precipitation route. The β-TCP phase content in sintered bioceramics samples is found to be highly dependent on the changes in technological parameters and it can be controlled with ending pH, synthesis temperature and thermal treatment. Pure, crystalline and highly thermally stable (up to 1300°C HAp bioceramics with homogenous grainy microstructure, grain size up to 200–250 nm and high open porosity can be successfully obtained by powder synthesized at elevated synthesis temperature of 70°C and stabilizing ending pH at 9.

  3. NdFeB nanoparticles prepared by wet-milling

    Energy Technology Data Exchange (ETDEWEB)

    Thielsch, Juliane; Lyubina, Julia; Woodcock, Thomas; Schultz, Ludwig; Gutfleisch, Oliver [IFW Dresden (Germany)

    2010-07-01

    Since the prediction of a giant energy product of textured nanocomposite magnets those materials where believed to be the next generation of permanent magnets. For effective exchange-coupling in such two-phase magnets grain sizes need to be in the range of the domain wall width of the hard magnetic phase. That makes a homogenous phase distribution and a microstructure with nanograins necessary. One option of preparing such materials is the synthesis of magnetic nanoparticles which further could be aligned and compacted to a bulk magnet. For this we performed wet-milling experiments of a NdFeGaNbB alloy. XRD studies revealed that by using a surfactant and a solvent during the high energy ball milling process amorphization sets in later than compared to dry milling experiments under the same conditions. Dynamic Light Scattering investigations showed a Gauss distribution of the particle size with a mean diameter of about 12nm which was also proven by TEM. Magnetic properties were measured with SQUID and showed so far rather poor coercivity values.

  4. Characterization and photo-chemical applications of nano-ZnO prepared by wet chemical and thermal decomposition methods

    International Nuclear Information System (INIS)

    Mousa, M.A.; Bayoumy, W.A.A.; Khairy, M.

    2013-01-01

    Graphical abstract: - Highlights: • Nano-ZnO particles were synthesized by soft-wet precipitation and dry methods. • ZnO nanoparticle with different morphologies was obtained. • Nano ZnO samples showed a high photocatalytic activity. • ZnO nanoparticle showed strong ultraviolet emission at room temperature. • The samples showed high biological activity depending on their synthetic method. - Abstract: Nano-crystalline ZnO particles were synthesized using two different routes: soft-wet and dry methods. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to identify the particles structures and morphologies, while X-ray diffraction (XRD) was used for verifying the particles crystal structure. The thermal stabilities of the particles were examined through thermal gravimetric analysis technique and their surface areas were calculated using BET method. Moreover, the photocatalytic activities were evaluated using UV–vis spectroscopy and photoluminescence (PL) characterization. The results showed that all the prepared ZnO samples possess a hexagonal wurtzite structure with high purity. Different particle sizes and morphologies of spheres, rods and wires were obtained depending on the preparation method used. Particle sizes obtained by the dry method are smaller than that found by the wet chemical method. The effects of both particle size and morphology on each of surface as well as optical properties, photocatalytic activity, dye/ZnO solar cell efficiency and biological activity have been studied and discussed

  5. Bioinspired heterostructured bead-on-string fibers via controlling the wet-assembly of nanoparticles.

    Science.gov (United States)

    Zhao, Lin; Song, Cheng; Zhang, Miaoxin; Zheng, Yongmei

    2014-09-21

    A kind of bioinspired heterostructured bead-on-string fiber (BHBF), composed of poly-(methyl methacrylate) (PMMA) and titanium tetrachloride (TiCl4) hydrolyzed nanoparticles, was prepared via integrating a wet-assembly system, including PMMA electrospinning, fog of nanoparticles and water coalescence at multi-stages. The wet-assembly of BHBF was regulated by the difference in surface energy and Laplace pressure. Especially, BHBF is characteristic of a hydrophilic rough bead for excellent water collection ability.

  6. Temperature dependence of morphology, structural and optical properties of ZnS nanostructures synthesized by wet chemical route

    International Nuclear Information System (INIS)

    Navaneethan, M.; Archana, J.; Nisha, K.D.; Hayakawa, Y.; Ponnusamy, S.; Muthamizhchelvan, C.

    2010-01-01

    Research highlights: → ZnS nanoparticles and nanorods have been synthesized by wet chemical route. → Higher annealing temperature influenced the change in morphology due to aggregation of the nanoparticles. → The temperature dependent optical properties were investigated. → Absorption edge of nanoparticles (295 nm) and nanorods (326 nm) were shifted towards shorter wavelength compared to bulk ZnS (337 nm) due to the quantum confinement effect. → ZnS nanoparticles exhibit high photoluminescence intensity than that of ZnS nanorods annealed at 180 o C. - Abstract: ZnS nanostructures have been synthesized by simple wet chemical route and annealed at two different temperatures of 50 o C and 180 o C. From the measurements of transmission electron microscopy and contact-mode atomic force microscopy, it is found that annealed temperature changes the morphology from nanoparticles to nanorods. The optical properties of the synthesized ZnS nanomaterial have been characterized by UV-visible absorption spectroscopy and photoluminescence spectroscopy. The structural and elemental analyses were carried out by powder X-ray diffraction pattern and energy dispersive X-ray absorption spectroscopy, respectively. Absorption edge of the nanoparticles (295 nm) and nanorods (326 nm) was shifted towards shorter wavelength compared to bulk ZnS (337 nm) due to the quantum confinement effect.

  7. Model of wet chemical etching of swift heavy ions tracks

    Science.gov (United States)

    Gorbunov, S. A.; Malakhov, A. I.; Rymzhanov, R. A.; Volkov, A. E.

    2017-10-01

    A model of wet chemical etching of tracks of swift heavy ions (SHI) decelerated in solids in the electronic stopping regime is presented. This model takes into account both possible etching modes: etching controlled by diffusion of etchant molecules to the etching front, and etching controlled by the rate of a reaction of an etchant with a material. Olivine ((Mg0.88Fe0.12)2SiO4) crystals were chosen as a system for modeling. Two mechanisms of chemical activation of olivine around the SHI trajectory are considered. The first mechanism is activation stimulated by structural transformations in a nanometric track core, while the second one results from neutralization of metallic atoms by generated electrons spreading over micrometric distances. Monte-Carlo simulations (TREKIS code) form the basis for the description of excitations of the electronic subsystem and the lattice of olivine in an SHI track at times up to 100 fs after the projectile passage. Molecular dynamics supplies the initial conditions for modeling of lattice relaxation for longer times. These simulations enable us to estimate the effects of the chemical activation of olivine governed by both mechanisms. The developed model was applied to describe chemical activation and the etching kinetics of tracks of Au 2.1 GeV ions in olivine. The estimated lengthwise etching rate (38 µm · h-1) is in reasonable agreement with that detected in the experiments (24 µm · h-1).

  8. New approach for direct chemical synthesis of hexagonal Co nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Abel, Frank M., E-mail: fabel@udel.edu [Physics and Astronomy, University of Delaware (United States); Tzitzios, Vasilis [Institute of Nanoscience and Nanotechnology, NCSR, Demokritos (Greece); Hadjipanayis, George C. [Physics and Astronomy, University of Delaware (United States)

    2016-02-15

    In this paper, we explore the possibility of producing hexagonal Cobalt nanoparticles, with high saturation magnetization by direct chemical synthesis. The nanoparticles were synthesized by reduction of anhydrous cobalt (II) chloride by NaBH{sub 4} in tetraglyme at temperatures in the range of 200–270 °C under a nitrogen–hydrogen atmosphere. The reactions were done at high temperatures to allow for the formation of as-made hexagonal cobalt. The size of the particles was controlled by the addition of different surfactants. The best magnetic properties so far were obtained on spherical hexagonal Co nanoparticles with an average size of 45 nm, a saturation magnetization of 143 emu/g and coercivity of 500 Oe. the saturation magnetization and coercivity were further improved by annealing the Co nanoparticles leading to saturation magnetization of 160 emu/g and coercivity of 540 Oe. - Highlights: • We synthesized hexagonal cobalt nanoparticles by a new wet chemical method. • We considered the effects of different surfactants on particles magnetic properties. • The as-made Co nanoparticles had magnetic properties of 143 emu/g and 500 Oe. • After annealing magnetic properties of 160 emu/g and 540 Oe were obtained.

  9. A simple wet chemical synthesis and characterization of hydroxyapatite nanorods

    International Nuclear Information System (INIS)

    Liu Yingkai; Hou Dedong; Wang Guanghou

    2004-01-01

    Calcium hydroxyapatite (Ca 5 (PO 4 ) 3 (OH):HAP) nanorods have been synthesized successfully via wet chemical technique at low temperature in the presence of suitable surfactant. The as-made nanorods have a diameter of 50-80 nm and a length of 0.5-1.2 μm. The microstructures and composition are characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectrometer (FT-IR). The formation mechanism of HAP nanorod is discussed in detail. It has been found that nanorods are pure, there is no HAP carbonated HAP. The growth mechanism of HAP nanorods could be explained by a soft template

  10. Trace impurities in coal by wet chemical methods

    International Nuclear Information System (INIS)

    Pollock, E.N.

    1975-01-01

    In determining trace elements in coal by wet chemical methods, conventional atomic absorption spectroscopy (AAS) was used to determine Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Cd, and Pb after dry ashing and acid dissolutions. A graphite furnace accessory was used for the flameless AAS determination of Bi, Se, Sn, Te, Be, Pb, As, Cd, Cr, Sb, and Ge. Mercury can be determined by flameless AAS after oxygen bomb combustion. Arsenic and antimony can be determined as their hydrides by AAS after low temperature ashing. Germanium, tin, bismuth, and tellurium can be determined as their hydrides by AAS after high temperature ashing. Selenium can be determined as its hydride by AAS after a special combustion procedure or after oxygen bomb combustion. Fluorine can be determined by specific ion analysis after oxygen bomb combustion. Boron can be determined colorimetrically. (U.S.)

  11. Gold nanoparticle growth control - Implementing novel wet chemistry method on silicon substrate

    KAUST Repository

    Al-Ameer, Ammar

    2013-04-01

    Controlling particle size, shape, nucleation, and self-assembly on surfaces are some of the main challenges facing electronic device fabrication. In this work, growth of gold nanoparticles over a wide range of sizes was investigated by using a novel wet chemical method, where potassium iodide is used as the reducing solution and gold chloride as the metal precursor, on silicon substrates. Four parameters were studied: soaking time, solution temperature, concentration of the solution of gold chloride, and surface pre-treatment of the substrate. Synthesized nanoparticles were then characterized using scanning electron microscopy (SEM). The precise control of the location and order of the grown gold overlayer was achieved by using focused ion beam (FIB) patterning of a silicon surface, pre-treated with potassium iodide. By varying the soaking time and temperature, different particle sizes and shapes were obtained. Flat geometrical shapes and spherical shapes were observed. We believe, that the method described in this work is potentially a straightforward and efficient way to fabricate gold contacts for microelectronics. © 2013 IEEE.

  12. Improved polymer thin-film wetting behavior through nanoparticle segregation to interfaces

    International Nuclear Information System (INIS)

    Krishnan, R S; Mackay, M E; Duxbury, P M; Hawker, C J; Asokan, Suba; Wong, Michael S; Goyette, Rick; Thiyagarajan, P

    2007-01-01

    We report a systematic study of improved wetting behavior for thin polymer films containing nanoparticles, as a function of nanoparticle size and concentration, the energy of the substrate and the dielectric properties of the nanoparticles. An enthalpy matched system consisting of polystyrene nanoparticles in linear polystyrene is used to show that nanoparticles are uniformly distributed in the film after spin coating and drying. However, on annealing the film above its bulk glass transition temperature these nanoparticles segregate strongly to the solid substrate. We find that for a wide range of film thicknesses and nanoparticle sizes, a substrate coverage of nanoparticles of approximately a monolayer is required for dewetting inhibition. Cadmium selenide quantum dots also inhibit dewetting of polystyrene thin films, again when a monolayer is present. Moreover, TEM microscopy images indicate that CdSe quantum dots segregate primarily to the air interface. Theoretical interpretation of these phenomena suggests that gain of linear chain configurational entropy promotes segregation of nanoparticles to the solid substrate, as occurs for polystyrene nanoparticles; however, for CdSe nanoparticles this is offset by surface energy or enthalpic terms which promote segregation of the nanoparticles to the air interface

  13. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    International Nuclear Information System (INIS)

    Shimpi, Navinchandra G.; Jain, Shilpa; Karmakar, Narayan; Shah, Akshara; Kothari, D.C.; Mishra, Satyendra

    2016-01-01

    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  14. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shimpi, Navinchandra G., E-mail: navin_shimpi@rediffmail.com [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Jain, Shilpa [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Karmakar, Narayan [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Shah, Akshara [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Kothari, D.C. [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); National Centre for Nanosciences & Nanotechnology, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Mishra, Satyendra [University Institute of Chemical Technology, North Maharashtra University, Jalgaon (India)

    2016-12-30

    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  15. Quantum confinement of lead titanate nanocrystals by wet chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kaviyarasu, K., E-mail: kaviyarasuloyolacollege@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Manikandan, E., E-mail: maniphysics@gmail.com [Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Central Research Laboratory, Sree Balaji Medical College & Hospital, Bharath University, Chrompet, Chennai, Tamil Nadu (India); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Maaza, M., E-mail: likmaaz@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa)

    2015-11-15

    Lead Titanate (PbTiO{sub 3)} is a category of the practical semiconductor metal oxides, which is widely applied in various scientific and industrial fields because of its catalytic, optical, and electrical properties. PbTiO{sub 3} nanocrystalline materials have attracted a wide attention due to their unique properties. PbTiO{sub 3} nanocrystals were investigated by X-ray diffraction (XRD) to identify the PbTiO{sub 3} nanocrystals were composed a tetragonal structure. The diameter of a single sphere was around 20 nm and the diameter reached up to 3 μm. The chemical composition of the samples and the valence states of elements were determined by X-ray photoelectron spectroscopy (XPS) in detail. - Highlights: • Single crystalline NSs of PbTiO{sub 3} fabricated by wet chemical method. • PbTiO{sub 3} NSs were uniform and continuous along the long axis. • Tetragonal perovskite structure with the diameter 20 nm and length 3 μm. • XPS spectrum was fitted with Lorentzian function respectively. • The size of the images is also 10 μm × 10 μm.

  16. Indium tin oxide films prepared via wet chemical route

    International Nuclear Information System (INIS)

    Legnani, C.; Lima, S.A.M.; Oliveira, H.H.S.; Quirino, W.G.; Machado, R.; Santos, R.M.B.; Davolos, M.R.; Achete, C.A.; Cremona, M.

    2007-01-01

    In this work, indium tin oxide (ITO) films were prepared using a wet chemical route, the Pechini method. This consists of a polyesterification reaction between an α-hydroxicarboxylate complex (indium citrate and tin citrate) with a polyalcohol (ethylene glycol) followed by a post annealing at 500 deg. C. A 10 at.% of doping of Sn 4+ ions into an In 2 O 3 matrix was successfully achieved through this method. In order to characterize the structure, the morphology as well as the optical and electrical properties of the produced ITO films, they were analyzed using different experimental techniques. The obtained films are highly transparent, exhibiting transmittance of about 85% at 550 nm. They are crystalline with a preferred orientation of [222]. Microscopy discloses that the films are composed of grains of 30 nm average size and 0.63 nm RMS roughness. The films' measured resistivity, mobility and charge carrier concentration were 5.8 x 10 -3 Ω cm, 2.9 cm 2 /V s and - 3.5 x 10 20 /cm 3 , respectively. While the low mobility value can be related to the small grain size, the charge carrier concentration value can be explained in terms of the high oxygen concentration level resulting from the thermal treatment process performed in air. The experimental conditions are being refined to improve the electrical characteristics of the films while good optical, chemical, structural and morphological qualities already achieved are maintained

  17. Non-monotonic wetting behavior of chitosan films induced by silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Praxedes, A.P.P.; Webler, G.D.; Souza, S.T. [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil); Ribeiro, A.S. [Instituto de Química e Biotecnologia, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil); Fonseca, E.J.S. [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil); Oliveira, I.N. de, E-mail: italo@fis.ufal.br [Instituto de Física, Universidade Federal de Alagoas, 57072-970 Maceió, AL (Brazil)

    2016-05-01

    Highlights: • The addition of silver nanoparticles modifies the morphology of chitosan films. • Metallic nanoparticles can be used to control wetting properties of chitosan films. • The contact angle shows a non-monotonic dependence on the silver concentration. - Abstract: The present work is devoted to the study of structural and wetting properties of chitosan-based films containing silver nanoparticles. In particular, the effects of silver concentration on the morphology of chitosan films are characterized by different techniques, such as atomic force microscopy (AFM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). By means of dynamic contact angle measurements, we study the modification on surface properties of chitosan-based films due to the addition of silver nanoparticles. The results are analyzed in the light of molecular-kinetic theory which describes the wetting phenomena in terms of statistical dynamics for the displacement of liquid molecules in a solid substrate. Our results show that the wetting properties of chitosan-based films are high sensitive to the fraction of silver nanoparticles, with the equilibrium contact angle exhibiting a non-monotonic behavior.

  18. Graphene oxide chemically decorated with hybrid Ag-Ru/chitosan nanoparticles: fabrication and properties

    OpenAIRE

    Veerapandian, Murugan; Neethirajan, Suresh

    2015-01-01

    Hybridization of distinct materials into a single nanoplatform is relevant to advance material’s properties for functional application such as biosensor platform. We report the synthesis and characterization of nanosheets of graphene oxide decorated with hybrid nanoparticles of silver-ruthenium bipyridine complex (Ag@[Ru(bpy)3]2+) core and chitosan shell. Hybrid nanoparticles were first obtained through a sequential wet-chemical approach using in situ reduction, electrostatic and coordination...

  19. Preparation of SnO2 Nanoparticles by Two Different Wet Chemistry Methods

    International Nuclear Information System (INIS)

    Ridha, N.J.; Akrajas Ali Umar; Muhammad Yahya; Muhammad Mat Salleh; Mohamad Hafizuddin Jumali

    2011-01-01

    The objective of this project is to prepare SnO 2 nanoparticles by two different wet chemistry methods namely sol gel and direct growth methods. The XRD results indicated that both samples are single phase SnO 2 . The FE-SEM micrographs displayed that SnO 2 nanoparticles prepared in first method exhibited a round shape with particle size around 15 nm while the second method produced SnO 2 nano rod with length and width of 570 nm and 55 nm respectively. Energy gap values for SnO 2 nanospheres and nano rods were 4.38 and 4.34 eV respectively. (author)

  20. Optical Detection and Sizing of Single Nano-Particles Using Continuous Wetting Films

    Science.gov (United States)

    Hennequin, Yves; McLeod, Euan; Mudanyali, Onur; Migliozzi, Daniel; Ozcan, Aydogan; Dinten, Jean-Marc

    2013-01-01

    The physical interaction between nano-scale objects and liquid interfaces can create unique optical properties, enhancing the signatures of the objects with sub-wavelength features. Here we show that the evaporation on a wetting substrate of a polymer solution containing sub-micrometer or nano-scale particles creates liquid micro-lenses that arise from the local deformations of the continuous wetting film. These micro-lenses have properties similar to axicon lenses that are known to create beams with a long depth of focus. This enhanced depth of focus allows detection of single nanoparticles using a low magnification microscope objective lens, achieving a relatively wide field-of-view, while also lifting the constraints on precise focusing onto the object plane. Hence, by creating these liquid axicon lenses through spatial deformations of a continuous thin wetting film, we transfer the challenge of imaging individual nano-particles to detecting the light focused by these lenses. As a proof of concept, we demonstrate the detection and sizing of single nano-particles (100 and 200 nm), CpGV granuloviruses as well as Staphylococcus epidermidis bacteria over a wide field of view of e.g., 5.10×3.75 mm2 using a ×5 objective lens with a numerical aperture of 0.15. In addition to conventional lens-based microscopy, this continuous wetting film based approach is also applicable to lensfree computational on-chip imaging, which can be used to detect single nano-particles over a large field-of-view of e.g., >20-30 mm2. These results could be especially useful for high-throughput field-analysis of nano-scale objects using compact and cost-effective microscope designs. PMID:23889001

  1. Structural, optical and photocatalytic properties of flower-like ZnO nanostructures prepared by a facile wet chemical method

    Directory of Open Access Journals (Sweden)

    Sini Kuriakose

    2013-11-01

    Full Text Available Flower-like ZnO nanostructures were synthesized by a facile wet chemical method. Structural, optical and photocatalytic properties of these nanostructures have been studied by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, photoluminescence (PL and UV–vis absorption spectroscopy. SEM and TEM studies revealed flower-like structures consisting of nanosheets, formed due to oriented attachment of ZnO nanoparticles. Flower-like ZnO structures showed enhanced photocatalytic activity towards sun-light driven photodegradation of methylene blue dye (MB as compared to ZnO nanoparticles. XRD, UV–vis absorption, PL, FTIR and TEM studies revealed the formation of Zn(OH2 surface layer on ZnO nanostructures upon ageing. We demonstrate that the formation of a passivating Zn(OH2 surface layer on the ZnO nanostructures upon ageing deteriorates their efficiency to photocatalytically degrade of MB.

  2. Production of BSA-poly(ethyl cyanoacrylate) nanoparticles as a coating material that improves wetting property.

    Science.gov (United States)

    Kim, S; Evans, K; Biswas, A

    2013-07-01

    Alkyl cyanoacrylates have long been used for the synthesis of colloidal nanoparticles. In the involved polymerization reaction, hydroxyl ions derived from dissociation of water have been used as an initiator. In the current research, an animal protein, bovine serum albumin (BSA) molecules were utilized as initiator for the polymerization. Following this reaction scheme, hydrophobic poly(ethyl cyanoacrylate)s were covalently bound to BSA, which is hydrophilic. Therefore, the resultant copolymer was amphiphilic in nature, and formed nanoparticles in the reaction medium. The suspension containing these nanoparticles showed an excellent coating capability on the surface of hydrophobic materials. A simple spray coating changed the wetting property of the material instantly and dramatically. Published by Elsevier B.V.

  3. Green wet chemical route to synthesize capped CdSe quantum dots

    Indian Academy of Sciences (India)

    In the present work, we report green synthesis of tartaric acid (TA) and triethanolamine (TEA) capped ... CdSe quantum dots; chemical bath deposition; capping; green chemistry; nanomaterials. 1. .... at high concentration of nanoparticles.

  4. Wet chemical synthesis of nickel supported on alumina catalysts

    International Nuclear Information System (INIS)

    Freire, Ranny Rodrigues; Costa, Talita Kenya Oliveira; Morais, Ana Carla da Fonseca Ferreira; Costa, Ana Cristina Figueiredo de Melo; Freitas, Normanda Lino de

    2016-01-01

    Heterogenic catalysts are those found to be in a different phase on the reaction when compared to the reactants and products. Preferred when compared to homogeneous catalysts due to the easiness on which the separation is processed. The objective of this study is to obtain and characterize Alumina based catalysts impregnated with Nickel (Al_2O_3), by wet impregnation. The alumina was synthesized by combustion reaction. Before and after the impregnation the catalysts were characterized by X-ray diffraction (XRD), granulometric analysis, the textural analysis will be held by nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results show a presence of a stable crystalline phase of Al2O3 in all the studied samples and after the impregnation the second phase formed was of NiO and NiAl_2O_4. The Al_2O_3 e Ni/Al_2O_3 catalysts resulted in clusters with a medium diameter of 18.9 and 14.2 μm, respectively. The catalysts show a medium-pore characteristic (medium pore diameter between 2 and 50 nm), the superficial area to Al_2O_3 and Ni/Al_2O_3 catalysts were 8.69 m"2/g and 5.56 m"2/g, respectively. (author)

  5. WetA bridges cellular and chemical development in Aspergillus flavus.

    Directory of Open Access Journals (Sweden)

    Ming-Yueh Wu

    Full Text Available Bridging cellular reproduction and survival is essential for all life forms. Aspergillus fungi primarily reproduce by forming asexual spores called conidia, whose formation and maturation is governed by the central genetic regulatory circuit BrlA→AbaA→WetA. Here, we report that WetA is a multi-functional regulator that couples spore differentiation and survival, and governs proper chemical development in Aspergillus flavus. The deletion of wetA results in the formation of conidia with defective cell walls and no intra-cellular trehalose, leading to reduced stress tolerance, a rapid loss of viability, and disintegration of spores. WetA is also required for normal vegetative growth, hyphal branching, and production of aflatoxins. Targeted and genome-wide expression analyses reveal that WetA exerts feedback control of brlA and that 5,700 genes show altered mRNA levels in the mutant conidia. Functional category analyses of differentially expressed genes in ΔwetA RNA-seq data indicate that WetA contributes to spore integrity and maturity by properly regulating the metabolic pathways of trehalose, chitin, α-(1,3-glucan, β-(1,3-glucan, melanin, hydrophobins, and secondary metabolism more generally. Moreover, 160 genes predicted to encode transcription factors are differentially expressed by the absence of wetA, suggesting that WetA may play a global regulatory role in conidial development. Collectively, we present a comprehensive model for developmental control that bridges spore differentiation and survival in A. flavus.

  6. Zirconia thin film preparation by wet chemical methods at low temperature

    NARCIS (Netherlands)

    Popovici, M.; Graaf, de J.; Verschuuren, M.A.; Graat, P.C.J.; Verheijen, M.A.

    2010-01-01

    In this study the preparation of zirconia thin films with a high refractive index at low temperature is aimed for. Two non-hydrolytic type approaches of wet chemical synthesis are presented. Both by sol–gel and colloid chemistry, highly transmissive, smooth thin films of zirconia cubic and/or

  7. A wet-chemical approach to perovskite and fluorite-type nanoceramics: synthesis and processing

    NARCIS (Netherlands)

    Veldhuis, Sjoerd

    2015-01-01

    In thesis the low-temperature, wet-chemical approach to various functional inorganic oxide materials is described. The main focus of this research is to control the material’s synthesis from liquid precursor to metal oxide powder or thin film; while understanding its formation mechanism. In

  8. Study on magnetite nanoparticles synthesized by chemical method

    International Nuclear Information System (INIS)

    Pei Wenli; Kumada, H.; Natusme, T.; Saito, H.; Ishio, S.

    2007-01-01

    Magnetite nanoparticles with controlled size were synthesized by chemical method. Higher deposition temperature and a rapid-raising temperature procedure are favorable to particle size distribution and fabrication of monodisperse nanoparticles. The larger nanoparticles can be synthesized by the two-step method. The large nanoparticle (up to 25 nm) without agglomeration was successfully produced. The saturation magnetization of 11 nm magnetite particles was 45 emu/g at room temperature, which is smaller than that of bulk magnetite due to surface effect. Hysteresis of the magnetite nanoparticle was very small, indicating superparamagnetic behavior. The magnetic domains of the 11 nm magnetite nanoparticles were successfully observed by MFM

  9. Wet etching and chemical polishing of InAs/GaSb superlattice photodiodes

    International Nuclear Information System (INIS)

    Chaghi, R; Cervera, C; Aït-Kaci, H; Grech, P; Rodriguez, J B; Christol, P

    2009-01-01

    In this paper, we studied wet chemical etching fabrication of the InAs/GaSb superlattice mesa photodiode for the mid-infrared region. The details of the wet chemical etchants used for the device process are presented. The etching solution is based on orthophosphoric acid (H 3 PO 4 ), citric acid (C 6 H 8 O 7 ) and H 2 O 2 , followed by chemical polishing with the sodium hypochlorite (NaClO) solution and protection with photoresist polymerized. The photodiode performance is evaluated by current–voltage measurements. The zero-bias resistance area product R 0 A above 4 × 10 5 Ω cm 2 at 77 K is reported. The device did not show dark current degradation at 77 K after exposition during 3 weeks to the ambient air

  10. CoPt nanoparticles by chemical reduction

    International Nuclear Information System (INIS)

    Wang, H.L.; Zhang, Y.; Huang, Y.; Zeng, Q.; Hadjipanayis, G.C.

    2004-01-01

    CoPt nanoparticles with a size of 1-2 nm were synthesized by chemical reduction using the solvents of water and alcohol. A phase transformation from the originally disordered face centered cubic (FCC) structure to an ordered face centered tetragonal L1 0 structure occurred after annealing, which results in the coercivity up to 9 kOe because of the high anisotropy of the tetragonal phase (K∼2-4x10 7 erg/cm 3 ) (Philos. Mag. 13 (1966) 567; IEEE Trans. Magn. 20 (1984) 1625). HREM images of as-grow Co 48 Pt 52 shows the single-crystalline FCC structure with the shape of columnar and spherical

  11. Influence of wet chemical cleaning on quantum efficiency of GaN photocathode

    International Nuclear Information System (INIS)

    Wang Xiao-Hui; Gao Pin; Wang Hong-Gang; Li Biao; Chang Ben-Kang

    2013-01-01

    GaN samples 1–3 are cleaned by a 2:2:1 solution of sulfuric acid (98%) to hydrogen peroxide (30%) to de-ionized water; hydrochloric acid (37%); or a 4:1 solution of sulfuric acid (98%) to hydrogen peroxide (30%). The samples are activated by Cs/O after the same annealing process. X-ray photoelectron spectroscopy after the different ways of wet chemical cleaning shows: sample 1 has the largest proportion of Ga, N, and O among the three samples, while its C content is the lowest. After activation the quantum efficiency curves show sample 1 has the best photocathode performance. We think the wet chemical cleaning method is a process which will mainly remove C contamination. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  12. Synthesis of Lead Sulfide Nanoparticles by Chemical Precipitation Method

    International Nuclear Information System (INIS)

    Chongad, L S; Sharma, A; Banerjee, M; Jain, A

    2016-01-01

    Lead sulfide (PbS) nanoparticles were prepared by chemical precipitation method (CPM) with the assistance of H 2 S gas. The microstructure and morphology of the synthesized nanoparticles have been investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns of the PbS nanoparticles reveal formation of cubic phase. To investigate the quality of prepared nanoparticles, the particles size, lattice constant, strain, dislocation density etc. have been determined using XRD. TEM images reveal formation of cubic nanoparticles and the particle size determined from TEM images agree well with those from XRD. (paper)

  13. Wet-chemical passivation of atomically flat and structured silicon substrates for solar cell application

    Science.gov (United States)

    Angermann, H.; Rappich, J.; Korte, L.; Sieber, I.; Conrad, E.; Schmidt, M.; Hübener, K.; Polte, J.; Hauschild, J.

    2008-04-01

    Special sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of differently oriented silicon to prepare very smooth silicon interfaces with excellent electronic properties on mono- and poly-crystalline substrates. Surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and scanning electron microscopy (SEM) investigations were utilised to develop wet-chemical smoothing procedures for atomically flat and structured surfaces, respectively. Hydrogen-termination as well as passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological processing. Compared to conventional pre-treatments, significantly lower micro-roughness and densities of surface states were achieved on mono-crystalline Si(100), on evenly distributed atomic steps, such as on vicinal Si(111), on silicon wafers with randomly distributed upside pyramids, and on poly-crystalline EFG ( Edge-defined Film-fed- Growth) silicon substrates. The recombination loss at a-Si:H/c-Si interfaces prepared on c-Si substrates with randomly distributed upside pyramids was markedly reduced by an optimised wet-chemical smoothing procedure, as determined by PL measurements. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H(n)/c-Si(p)/Al) with textured c-Si substrates the smoothening procedure results in a significant increase of short circuit current Isc, fill factor and efficiency η. The scatter in the cell parameters for measurements on different cells is much narrower, as compared to conventional pre-treatments, indicating more well-defined and reproducible surface conditions prior to a-Si:H emitter deposition and/or a higher stability of the c-Si surface against variations in the a-Si:H deposition conditions.

  14. Fabrication of high quality GaN nanopillar arrays by dry and wet chemical etching

    OpenAIRE

    Paramanik, Dipak; Motayed, Abhishek; King, Matthew; Ha, Jong-Yoon; Kryluk, Sergi; Davydov, Albert V.; Talin, Alec

    2013-01-01

    We study strain relaxation and surface damage of GaN nanopillar arrays fabricated using inductively coupled plasma (ICP) etching and post etch wet chemical treatment. We controlled the shape and surface damage of such nanopillar structures through selection of etching parameters. We compared different substrate temperatures and different chlorine-based etch chemistries to fabricate high quality GaN nanopillars. Room temperature photoluminescence and Raman scattering measurements were carried ...

  15. Nitride-based Schottky diodes and HFETs fabricated by photo-enhanced chemical wet etching

    International Nuclear Information System (INIS)

    Su, Y.K.; Chang, S.J.; Kuan, T.M.; Ko, C.H.; Webb, J.B.; Lan, W.H.; Cherng, Y.T.; Chen, S.C.

    2004-01-01

    Photo-enhanced chemical (PEC) wet etching technology was used to etch GaN and AlGaN epitaxial layers. It was found that the maximum etch rates were 510, 1960, 300, and 0 nm/mm for GaN, Al 0.175 Ga 0.825 N, Al 0.23 Ga 0.77 N, and Al 0.4 Ga 0.6 N, respectively. It was also found that we could achieve a high Al 0.175 Ga 0.825 N to GaN etch rate ratio of 12.6. Nitride-based Schottky diodes and heterostructure field effect transistors (HFETs) were also fabricated by PEC wet etching. It was found that we could achieve a saturated I D larger than 850 mA/mm and a maximum g m about 163 mS/mm from PEC wet etched HFET with a 0.5 μm gate length. Compared with dry etched devices, the leakage currents observed from the PEC wet etched devices were also found to be smaller

  16. Chemical nature of catalysts of oxide nanoparticles in environment

    Indian Academy of Sciences (India)

    Carbon nanostructures (CNS) are often grown using oxide nanoparticles as catalyst in chemical vapour deposition and these oxides are not expected to survive as such during growth. In the present study, the catalysts of cobalt- and nickel oxide-based nanoparticles of sizes varying over a range have been reduced at 575 ...

  17. Effects of Dry-Milling and Wet-Milling on Chemical, Physical and Gelatinization Properties of Rice Flour

    Directory of Open Access Journals (Sweden)

    Jitranut Leewatchararongjaroen

    2016-09-01

    Full Text Available Rice flour from nine varieties, subjected to dry- and wet-milling processes, was determined for its physical and chemical properties. The results revealed that milling method had an effect on properties of flour. Wet-milling process resulted in flour with significantly lower protein and ash contents and higher carbohydrate content. Wet-milled flour also tended to have lower lipid content and higher amylose content. In addition, wet-milled rice flour contained granules with smaller average size compared to dry-milled samples. Swelling power at 90 °C of wet-milled samples was higher while solubility was significantly lower than those of dry-milled flour. Dry milling process caused the destruction of the crystalline structure and yielded flour with lower crystallinity compared to wet-milling process, which resulted in significantly lower gelatinization enthalpy.

  18. Unveiling the wet chemical etching characteristics of polydimethylsiloxane film for soft micromachining applications

    International Nuclear Information System (INIS)

    Kakati, A; Maji, D; Das, S

    2017-01-01

    Micromachining of a polydimethylsiloxane (PDMS) microstructure by wet chemical etching is explored for microelectromechanical systems (MEMS) and microfluidic applications. A 100 µ m thick PDMS film was patterned with different microstructure designs by wet chemical etching using a N-methyl-2-pyrrolidone (C 16 H 36 FN) and tetra-n-butylammonium fluoride (C 5 H 9 NO) mixture solution with 3:1 volume ratio after lithography for studying etching characteristics. The patterning parameters, such as etch rate, surface roughness, pH of etchant solution with time, were thoroughly investigated. A detailed study of surface morphology with etching time revealed nonlinear behaviour of the PDMS surface roughness and etch rate. A maximum rate of 1.45 µ m min −1 for 10 min etching with surface roughness of 360 nm was achieved. A new approach of wet chemical etching with pH controlled doped etchant was introduced for lower surface roughness of etched microstructures, and a constant etch rate during etching. Variation of the etching rate and surface roughness by pH controlled etching was performed by doping 5–15 gm l −1 of silicic acid (SiO 2xH2 O) into the traditional etchant solution. PDMS etching by silicic acid doped etchant solution showed a reduction in surface roughness from 400 nm to 220 nm for the same 15 µ m etching. This study is beneficial for micromachining of various MEMS and microfluidic structures such as micropillars, microchannels, and other PDMS microstructures. (paper)

  19. Wet-chemical approach for the cell-adhesive modification of polytetrafluoroethylene

    International Nuclear Information System (INIS)

    Gabriel, Matthias; Dahm, Manfred; Vahl, Christian-F

    2011-01-01

    Polytetrafluoroethylene (PTFE), a frequently utilized polymer for the fabrication of synthetic vascular grafts, was surface-modified by means of a wet-chemical process. The inherently non-cell-adhesive polymer does not support cellular attachment, a prerequisite for the endothelialization of luminal surface grafts in small diameter applications. To impart the material with cell-adhesive properties a treatment with sodium-naphthalene provided a basis for the subsequent immobilization of the adhesion promoting RGD-peptide using a hydroxy- and amine-reactive crosslinker. Successful conjugation was shown with cell culture experiments which demonstrated excellent endothelial cell growth on the modified surfaces.

  20. Direct synthesis of nanocrystalline oxide powders by wet-chemical techniques

    Directory of Open Access Journals (Sweden)

    Vladimir V. Srdić

    2010-09-01

    Full Text Available In a recent period there is a great need for increasing the knowledge of tailoring the innovative procedures for the synthesis of electroceramic nanopowders and materials with improved quality for specific application. In order to produce electroceramics with desirable microstructure and properties, synthesis of stoichiometric, ultra-fine and agglomerate free powders with narrow size distributions is one of the most important steps. Within this scope, in the present paper we summarize our recent results on direct synthesis of some important perovskites and ferrites nanopowders by wet-chemical techniques.

  1. Chemical synthesis and characterization of palladium nanoparticles

    International Nuclear Information System (INIS)

    Nguyen, Viet Long; Hayakawa, Tomokatsu; Nogami, Masayuki; Nguyen, Duc Chien; Hirata, Hirohito; Ohtaki, Michitaka

    2010-01-01

    This work presents the results of the successful preparation of Pd nanoparticles by the polyol method and the proposed techniques of controlling their size and shape. Polyvinylpyrrolidone (PVP) stabilized Pd nanoparticles of various shapes with the largest sizes in the forms of octahedrons (24 nm), tetrahedrons (22 nm) and cubes (20 nm) have been obtained by alcohol reduction in ethanol with the addition of a hydrochloric acid catalyst. Moreover, PVP–Pd nanoparticles of well-controlled spherical shapes have also been prepared by a modified polyol method. PVP–Pd nanoparticles of cubic, octahedral, tetrahedral and spherical shapes with well-controlled size achieved by using ethylene glycol (EG) as reductant and various inorganic species were also fabricated. In particular, Pd nanorods with sizes of 47 nm and 16 nm formed due to the anisotropic growth mechanism of Pd nanoparticles were found. At the same time, tetrahedral particles of sharp shapes of 120 nm and 70 nm sizes have been observed. A high concentration of inorganic species was used to control the size and shape of the Pd nanoparticles, leading to the appearance of various irregular sizes and shapes. There was evidence of the very sharp corners and edges of tetrahedral and octahedral Pd nanoparticles or others that were formed in the clustering and combination of the seeds of smaller particles

  2. Wet chemical synthesis of LiBaF{sub 3} phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Vartika S., E-mail: svmoharil@yahoo.com [Physics Department, Shri Ramdeobaba K.N. Engineering College, Katol Road, Nagpur 440 013 (India); Joshi, C.P. [Physics Department, Shri Ramdeobaba K.N. Engineering College, Katol Road, Nagpur 440 013 (India); Moharil, S.V. [Department of Physics, R.T.M. Nagpur University, Nagpur 440 010 (India)

    2013-12-05

    Highlights: •LiBaF{sub 3}:RE{sup 3+} phosphors synthesized by a simple wet chemical method. •Ce{sup 3+} and Tb{sup 3+} emissions observed in as-prepared powders without any thermal treatment. •Intense Eu{sup 2+} emission observed after annealing in reductive atmosphere. -- Abstract: LiBaF{sub 3} has great potential applications as X-ray storage phosphor, slow neutron imaging, scintillator, vacuum ultraviolet (VUV) optical lithography, etc. Conventionally, LiBaF{sub 3} is prepared by solid state reaction between the constituent fluorides. However, the preparation of phase pure material and especially single crystals is rather tricky due to incongruent melting. For the first time, a wet chemical preparation of rare earth activated LiBaF{sub 3} is described here. As precipitated powders containing Ce{sup 3+} or Tb{sup 3+} exhibited characteristic luminescence. For observing Eu{sup 2+} emission, it was necessary to heat the powders in a reductive atmosphere. It is suggested that phosphors prepared by this method may prove useful in applications like OSL, X-ray imaging, etc. which do not require large single crystals.

  3. Wet chemical deposition of single crystalline epitaxial manganite thin films with atomically flat surface

    International Nuclear Information System (INIS)

    Mishra, Amita; Dutta, Anirban; Samaddar, Sayanti; Gupta, Anjan K.

    2013-01-01

    We report the wet chemical deposition of single crystalline epitaxial thin films of the colossal magneto-resistive manganite La 0.67 Sr 0.33 MnO 3 on the lattice-matched (001)-face of a La 0.3 Sr 0.7 Al 0.65 Ta 0.35 O 3 substrate. Topographic images of these films taken with a scanning tunneling microscope show atomically flat terraces separated by steps of monatomic height. The resistivity of these films shows an insulator-metal transition at 310 K, nearly coincident with the Curie temperature of 340 K, found from magnetization measurements. The films show a magnetoresistance of 7% at 300 K and 1.2 T. Their saturation magnetization value at low temperatures is consistent with that of the bulk. - Highlights: ► Wet chemical deposition of La 0.67 Sr 0.33 MnO 3 (LSMO) on a lattice-matched substrate. ► Single crystalline epitaxial LSMO films obtained. ► Flat terraces separated by monatomic steps observed by scanning tunneling microscope

  4. Optimization of wet lay-up conditions for steam generators hydrazine chemical treatment

    International Nuclear Information System (INIS)

    Long, A.; Organista, M.; Brun, C.; Combrade, P.

    2002-01-01

    Since a long time, hydrazine is used as a chemical agent to prevent corrosion of unalloyed steels. This is a conventional treatment widely used by nuclear power plant operators. But its application in SG lay-up at French nuclear power plants has, however, lead to some drawbacks. Effluent releases: Due to regulation relative to release of hydrazine and alkaline chemical compounds, some plant operators limit the concentrations of reagents to levels that could lead to insufficient protection of materials. Safety hazards associated with SG nitrogen blanketing: Prohibiting use of nitrogen blankets for SG wet lay-up due to associated safety hazards could likewise jeopardize corrosion protection at normally specified hydrazine levels. As the exact limits of hydrazine action against corrosion during SG lay-up are not well known, it is sometimes difficult to evaluate the risk associated to low dosage of N 2 H 4 . In order to answer to these problems, Framatome ANP (France) decided to carry out a test program aimed to determine the limit conditions for use of hydrazine in a wet lay-up environment. (authors)

  5. Chemical surface tuning electrocatalysis of redox-active nanoparticles

    DEFF Research Database (Denmark)

    Zhu, Nan; Ulstrup, Jens; Chi, Qijin

    This work focuses on electron transfer (ET) and electrocatalysis of inorganic hybrid Prussian blue nanoparticles (PBNPs, 6 nm) immobilized on different chemical surfaces. Through surface self-assembly chemistry, we have enabled to tune chemical properties of the electrode surface. Stable immobili...

  6. Effect of experimental factors on magnetic properties of nickel nanoparticles produced by chemical reduction method using a statistical design

    International Nuclear Information System (INIS)

    Vaezi, M.R.; Barzgar Vishlaghi, M.; Farzalipour Tabriz, M.; Mohammad Moradi, O.

    2015-01-01

    Highlights: • Superparamagnetic nickel nanoparticles are synthesized by wet chemical reduction. • Effects of synthesis parameters on magnetic properties are studied. • Central composite experimental design is used for building an empirical model. • Solvents ratio was more influential than reactants mixing rate. - Abstract: Nickel nanoparticles were synthesized by chemical reduction method in the absence of any surface capping agent. The effect of reactants mixing rate and the volume ratio of methanol/ethanol as solvent on the morphology and magnetic properties of nickel nanoparticles were studied by design of experiment using central composite design. X-ray diffraction (XRD) technique and Transmission Electron Microscopy (TEM) were utilized to characterize the synthesized nanoparticles. Size distribution of particles was studied by Dynamic Light Scattering (DLS) technique and magnetic properties of produced nanoparticles were investigated by Vibrating Sample Magnetometer (VSM) apparatus. The results showed that the magnetic properties of nickel nanoparticles were more influenced by volume ratio of methanol/ethanol than the reactants mixing rate. Super-paramagnetic nickel nanoparticles with size range between 20 and 50 nm were achieved when solvent was pure methanol and the reactants mixing rate was kept at 70 ml/h. But addition of more ethanol to precursor solvent leads to the formation of larger particles with broader size distribution and weak ferromagnetic or super-paramagnetic behavior

  7. Synthesis of superparamagnetic δ-FeOOH nanoparticles by a chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, Naoki, E-mail: nnishida@rs.tus.ac.jp [Department of Chemistry, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Amagasa, Shota [Department of Chemistry, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Kobayashi, Yoshio [Department of Engineering Science, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Yamada, Yasuhiro [Department of Chemistry, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan)

    2016-11-30

    Highlights: • The spherical δ-FeOOH nanoparticles were synthesized by a chemical reaction of FeCl{sub 2}. • The δ-FeOOH nanoparticles showed superparamagnetic behavior. • A mixture of Fe{sub 3}O{sub 4} and Fe(OH){sub 2} were rapidly oxidized into δ-FeOOH nanoparticles. - Abstract: δ-FeOOH nanoparticles were synthesized via the oxidation of precipitates obtained from the reaction of FeCl{sub 2} and N{sub 2}H{sub 4} in the presence of sodium tartrate and gelatin in an alkaline condition. These δ-FeOOH particles were subsequently examined using transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), Mössbauer spectroscopy, and superconducting quantum interference device (SQUID) assessment. The average size of the δ-FeOOH nanoparticles was below 10 nm, and these particles exhibited superparamagnetic behavior as a result of this small size. The precursors of the δ-FeOOH nanoparticles were also characterized as a means of elucidating the reaction mechanism. Precipitates prior to oxidation upon rinsing with water and ethanol were analyzed by obtaining XRD patterns and Mössbauer spectra of wet and frozen samples, respectively. The precipitates obtained by the reaction of FeCl{sub 2} and N{sub 2}H{sub 4} were found to consist of a mixture of Fe{sub 3}O{sub 4} and Fe(OH){sub 2}, and it is believed that these species then rapidly oxidized into δ-FeOOH nanoparticles.

  8. Radiation chemical route for preparation of metal nanoparticles

    International Nuclear Information System (INIS)

    Kapoor, S.; Mukherjee, T.

    2006-01-01

    Nanoparticles show properties that are neither seen in the bulk or at atomic level. The unusual properties are governed by quantum size effect. Due to this various methodologies have been endeavored to control the size of the particles. In the present work we show the use of two complimentary techniques (radiation and photo) to synthesize and control the size of the metal particles. In-situ synthesis of fine silver, thallium and cadmium particles has been carried out by gamma-irradiation and electron pulse irradiation at room temperature in the pre-organized gel of polyacrylamide or cyclodextrin cavity. The role of generation of nuclei in high concentrations in stabilization of metal nanoparticles in hydrophobic cavity is shown. Similarly the importance of entrapment of metal ions in the polymer matrix during its formation is highlighted. The work is further extended to exploit the microemulsion droplets for stabilization of Cd nanoparticles. Utility of pulse radiolysis in probing the mechanism of the formation of metal nanoparticles is also shown. Ultrafast laser pulses were employed to control the morphology of the pre-prepared Pt nanoparticles. The changes in reduction of shape and size are considered to occur through melting and vaporization of the nanoparticles. Pt nanoparticles were coated on the inner walls of the tubular pyrex reactor and tested for their catalytic activity for oxidation of CO. It was observed that Pt nanoparticles prepared in the presence of a stabilizer (gelatin) showed a higher tendency to adhere to the inner walls of the pyrex reactor as compared to that prepared in the presence of silica nanoparticles. The catalyst was found to be active at ≥150 degree C giving CO 2 . Chemically reduced Pt nanoparticles stabilized on silica nanoparticles gave ∼7% CO conversion per hr. However, radiolytically prepared Pt nanoaprticles stabilized by gelatin gave ∼10% conversion per hr. The data indicates that catalytic oxidation of CO takes place

  9. Combined wet-chemical process to synthesize 65PMN-35PT nanosized powders

    International Nuclear Information System (INIS)

    Santos, Luis P.S.; Longo, Elson; Leite, Edson R.; Camargo, Emerson R.

    2004-01-01

    Columbite MgNb 2 O 6 precursors were synthesized by a wet-chemical method by means of the dissolution of Nb 2 O 5 .5H 2 O and magnesium carbonate in a solution of oxalic acid. Pure 65PMN-35PT powders could be obtained by the columbite method with the use of the partial oxalate and oxidant peroxo methods. Powders were characterized by X-ray diffraction and FT-Raman spectroscopy showing that pure 65PMN-35PT are obtained when the powders are calcined up to 800 deg. C, without any trace of Pb-Nb pyrochlore. Cubic Pb 1,86 Mg 0.24 Nb 1.76 O 6.5 pyrochlore phase is formed by lead loss in the powders calcined at 900 deg. C and higher temperatures as undoubtedly characterized by Raman spectroscopy

  10. Washing of gel particles in wet chemical manufacture of reactor fuel particles

    International Nuclear Information System (INIS)

    Ringel, H.

    1980-07-01

    In the manufacture of HTR fuel particles and particles of fertile material by wet chemical methods, the ammonium nitrate formed during the precipitation reaction must be washed out of the gel particles. This washing process has been investigated theoretically and experimentally. A counter-current washer has been developed which in particular takes account of the aspects of refabrication - such as compact construction and minimum waste. A counter-current washing column of 17 mm internal diameter and 640 mm length gives to gel particle throughput of 0.65 1/h. The volume ratio of wash water to gel particles is 5, and the residual nitrate concentration in the particles is 7 x 10 -3 mols of NO - 3 /1. (orig.) [de

  11. Oxidation Kinetics of Chemically Vapor-Deposited Silicon Carbide in Wet Oxygen

    Science.gov (United States)

    Opila, Elizabeth J.

    1994-01-01

    The oxidation kinetics of chemically vapor-deposited SiC in dry oxygen and wet oxygen (P(sub H2O) = 0.1 atm) at temperatures between 1200 C and 1400 C were monitored using thermogravimetric analysis. It was found that in a clean environment, 10% water vapor enhanced the oxidation kinetics of SiC only very slightly compared to rates found in dry oxygen. Oxidation kinetics were examined in terms of the Deal and Grove model for oxidation of silicon. It was found that in an environment containing even small amounts of impurities, such as high-purity Al2O3 reaction tubes containing 200 ppm Na, water vapor enhanced the transport of these impurities to the oxidation sample. Oxidation rates increased under these conditions presumably because of the formation of less protective sodium alumino-silicate scales.

  12. Fabrication of Aligned Polyaniline Nanofiber Array via a Facile Wet Chemical Process.

    Science.gov (United States)

    Sun, Qunhui; Bi, Wu; Fuller, Thomas F; Ding, Yong; Deng, Yulin

    2009-06-17

    In this work, we demonstrate for the first time a template free approach to synthesize aligned polyaniline nanofiber (PN) array on a passivated gold (Au) substrate via a facile wet chemical process. The Au surface was first modified using 4-aminothiophenol (4-ATP) to afford the surface functionality, followed subsequently by an oxidation polymerization of aniline (AN) monomer in an aqueous medium using ammonium persulfate as the oxidant and tartaric acid as the doping agent. The results show that a vertically aligned PANI nanofiber array with individual fiber diameters of ca. 100 nm, heights of ca. 600 nm and a packing density of ca. 40 pieces·µm(-2) , was synthesized. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Fabrication and Photovoltaic Characteristics of Coaxial Silicon Nanowire Solar Cells Prepared by Wet Chemical Etching

    Directory of Open Access Journals (Sweden)

    Chien-Wei Liu

    2012-01-01

    Full Text Available Nanostructured solar cells with coaxial p-n junction structures have strong potential to enhance the performances of the silicon-based solar cells. This study demonstrates a radial junction silicon nanowire (RJSNW solar cell that was fabricated simply and at low cost using wet chemical etching. Experimental results reveal that the reflectance of the silicon nanowires (SNWs declines as their length increases. The excellent light trapping was mainly associated with high aspect ratio of the SNW arrays. A conversion efficiency of ∼7.1% and an external quantum efficiency of ∼64.6% at 700 nm were demonstrated. Control of etching time and diffusion conditions holds great promise for the development of future RJSNW solar cells. Improving the electrode/RJSNW contact will promote the collection of carries in coaxial core-shell SNW array solar cells.

  14. Simulation of the evolution of fused silica's surface defect during wet chemical etching

    Science.gov (United States)

    Liu, Taixiang; Yang, Ke; Li, Heyang; Yan, Lianghong; Yuan, Xiaodong; Yan, Hongwei

    2017-08-01

    Large high-power-laser facility is the basis for achieving inertial confinement fusion, one of whose missions is to make fusion energy usable in the near future. In the facility, fused silica optics plays an irreplaceable role to conduct extremely high-intensity laser to fusion capsule. But the surface defect of fused silica is a major obstacle limiting the output power of the large laser facility and likely resulting in the failure of ignition. To mitigate, or event to remove the surface defect, wet chemical etching has been developed as a practical way. However, how the surface defect evolves during wet chemical etching is still not clearly known so far. To address this problem, in this work, the three-dimensional model of surface defect is built and finite difference time domain (FDTD) method is developed to simulate the evolution of surface defect during etching. From the simulation, it is found that the surface defect will get smooth and result in the improvement of surface quality of fused silica after etching. Comparatively, surface defects (e.g. micro-crack, scratch, series of pinholes, etc.) of a typical fused silica at different etching time are experimentally measured. It can be seen that the simulation result agrees well with the result of experiment, indicating the FDTD method is valid for investigating the evolution of surface defect during etching. With the finding of FDTD simulation, one can optimize the treatment process of fused silica in practical etching or even to make the initial characterization of surface defect traceable.

  15. Synthesis of Copper Nanoparticles in Ethylene Glycol by Chemical Reduction with Vanadium (+2 Salts

    Directory of Open Access Journals (Sweden)

    Andrea Pietro Reverberi

    2016-09-01

    Full Text Available Copper nanoparticles have been synthesized in ethylene glycol (EG using copper sulphate as a precursor and vanadium sulfate as an atypical reductant being active at room temperature. We have described a technique for a relatively simple preparation of such a reagent, which has been electrolytically produced without using standard procedures requiring an inert atmosphere and a mercury cathode. Several stabilizing agents have been tested and cationic capping agents have been discarded owing to the formation of complex compounds with copper ions leading to insoluble phases contaminating the metallic nanoparticles. The elemental copper nanoparticles, stabilized with polyvinylpyrrolidone (PVP and sodium dodecyl sulphate (SDS, have been characterized for composition by energy dispersive X-ray spectroscopy (EDS, and for size by dynamic light scattering (DLS, and transmission electron microscopy (TEM, giving a size distribution in the range of 40–50 nm for both stabilizing agents. From a methodological point of view, the process described here may represent an alternative to other wet-chemical techniques for metal nanoparticle synthesis in non-aqueous media based on conventional organic or inorganic reductants.

  16. Microbes and associated soluble and volatile chemicals on periodically wet household surfaces.

    Science.gov (United States)

    Adams, Rachel I; Lymperopoulou, Despoina S; Misztal, Pawel K; De Cassia Pessotti, Rita; Behie, Scott W; Tian, Yilin; Goldstein, Allen H; Lindow, Steven E; Nazaroff, William W; Taylor, John W; Traxler, Matt F; Bruns, Thomas D

    2017-09-26

    Microorganisms influence the chemical milieu of their environment, and chemical metabolites can affect ecological processes. In built environments, where people spend the majority of their time, very little is known about how surface-borne microorganisms influence the chemistry of the indoor spaces. Here, we applied multidisciplinary approaches to investigate aspects of chemical microbiology in a house. We characterized the microbial and chemical composition of two common and frequently wet surfaces in a residential setting: kitchen sink and bathroom shower. Microbial communities were studied using culture-dependent and independent techniques, including targeting RNA for amplicon sequencing. Volatile and soluble chemicals from paired samples were analyzed using state-of-the-art techniques to explore the links between the observed microbiota and chemical exudates. Microbial analysis revealed a rich biological presence on the surfaces exposed in kitchen sinks and bathroom shower stalls. Microbial composition, matched for DNA and RNA targets, varied by surface type and sampling period. Bacteria were found to have an average of 25× more gene copies than fungi. Biomass estimates based on qPCR were well correlated with measured total volatile organic compound (VOC) emissions. Abundant VOCs included products associated with fatty acid production. Molecular networking revealed a diversity of surface-borne compounds that likely originate from microbes and from household products. Microbes played a role in structuring the chemical profiles on and emitted from kitchen sinks and shower stalls. Microbial VOCs (mVOCs) were predominately associated with the processing of fatty acids. The mVOC composition may be more stable than that of microbial communities, which can show temporal and spatial variation in their responses to changing environmental conditions. The mVOC output from microbial metabolism on kitchen sinks and bathroom showers should be apparent through careful

  17. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    International Nuclear Information System (INIS)

    Angermann, Heike

    2014-01-01

    Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D it (E), and density D it,min of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly based on

  18. Structural and morphological study of Zn0.9Mn0.05Fe0.05O synthesized by sol-gel wet chemical precipitation route

    Science.gov (United States)

    Jain, S. K.; Dolia, S. N.; Choudhary, B. L.; Prashant, B. L.

    2018-04-01

    Transition metal substituted Zinc oxide (ZnO) has drawn a great deal of attention due to its excellent properties. Zn0.9Mn0.05Fe0.05O sample synthesized was by Sol-gel wet chemical precipitation route at temperature 350°C. The crystallinity and the structure of Zn0.9Mn0.05Fe0.05O was determined by X-ray diffraction by Cu-Kα radiations operated at 40kV and 35mA in the range of 20° to 80°. The pattern gets indexed in wurtzite (hexagonal) structure with lattice constants a=b=3.2525Å and c=5.2071Å and approves the single phase material with no impurity. The values of particle size assessed by Debye Scherer’s (DS) formula lie in the range of 13nm to 33nm indicating the nano-crystalline nature of the sample. The morphological analysis of the sample was performed by Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) measurements. The observed size of Zn0.9Mn0.05Fe0.05O nanoparticles by TEM micrograph exhibits the similar trend with the size calculated by Debye-Scherer formula. TEM image show the irregular shape of the nanoparticles and particle size lies in the range of 10-35nm. Similar to SEM image, the slight agglomeration of the nanoparticles have been observed from TEM.

  19. Investigation of microstructure and mechanical properties of phosphocalcic bone substitute using the chemical wet method

    Science.gov (United States)

    Alimi, Latifa; Bahloul, Lynda; Azzi, Afef; Guerfi, Souad; Ismail, Fadhel; Chaoui, Kamel

    2018-05-01

    Selection of calcium phosphate base materials in reconstructive bone surgery is justified by the surprising similarities in chemical compositions with human bones. The closest to natural apatite material is the hydroxyapatite (HAp) which has a chemical composition based on calcium and phosphate (Ca10(PO4)6(OH)2). In this study, HAp is synthesized using the wet precipitation method from hydrated calcium chloride (CaCl2,12H2O) and di-sodium hydrogen phosphate di-hydrate (HNa2PO4,2H2O). The powder is calcinated at 900°C and 1200°C in order to compare with sintered condition at 1150°C. Vickers microhardness tests and X-ray diffraction analyzes are used for the characterization of the crystalline material. Mechanical properties (Hv, σe, σr, and KC) and the degree of crystallinity (Xc) are discussed according to heat treatment temperatures. Results indicate that heat treating the powder at 1200°C increased crystallinity up to 72%. At the same time, microhardness increased with temperature and even outmatched the sintered case at 1150°C. Fracture toughness is ameliorated with increasing heat treatment temperature by more than two folds.

  20. Chemical nature of catalysts of oxide nanoparticles in environment ...

    Indian Academy of Sciences (India)

    12

    Chemical nature of catalysts of oxide nanoparticles in environment prevailing during growth of carbon nanostructures by CCVD. M. Jana*, A. Sil and S. Ray. †. Department of Metallurgical and Materials Engineering. Indian Institute of Technology Roorkee. Roorkee 247 667, India. Present address: *School of Materials ...

  1. Characterization of chemically synthesized CdS nanoparticles

    Indian Academy of Sciences (India)

    Similar to the effects of charge carriers on optical properties, confinement of optical and acoustic phonons leads to interesting changes in the phonon spectra. In the present work, we have synthesized nanoparticles of CdS using chemical precipitation technique. The crystal structure and grain size of the particles are studied ...

  2. Analysis of Wetting and Contact Angle Hysteresis on Chemically Patterned Surfaces

    KAUST Repository

    Xu, Xianmin; Wang, Xiaoping

    2011-01-01

    Wetting and contact angle hysteresis on chemically patterned surfaces in two dimensionsare analyzed from a stationary phase-field model for immiscible two phase fluids. We first study the sharp-interface limit of the model by the method of matched asymptotic expansions. We then justify the results rigorously by the γ-convergence theory for the related variational problem and study the properties of the limiting minimizers. The results also provide a clear geometric picture of the equilibrium configuration of the interface. This enables us to explicitly calculate the total surface energy for the two phase systems on chemically patterned surfaces with simple geometries, namely the two phase flow in a channel and the drop spreading. By considering the quasi-staticmotion of the interface described by the change of volume (or volume fraction), we can follow the change-of-energy landscape which also reveals the mechanism for the stick-slip motion of the interface and contact angle hysteresis on the chemically patterned surfaces. As the interface passes throughpatterned surfaces, we observe not only stick-slip of the interface and switching of the contact angles but also the hysteresis of contact point and contact angle. Furthermore, as the size of the patternde creases to zero, the stick-slip becomes weaker but the hysteresis becomes stronger in the sense that one observes either the advancing contact angle or the receding contact angle (when the interface ismoving in the opposite direction) without the switching in between. © 2011 Society for Industrial and Applied Mathematics.

  3. Evaluation on nitrogen oxides and nanoparticle removal and nitrogen monoxide generation using a wet-type nonthermal plasma reactor

    Science.gov (United States)

    Takehana, Kotaro; Kuroki, Tomoyuki; Okubo, Masaaki

    2018-05-01

    Nitrogen oxides (NOx) emitted from power plants and combustion sources cause air pollution problems. Selective catalytic reduction technology is remarkably useful for NOx removal. However, there are several drawbacks such as preparation of reducing agents, usage of harmful heavy metals, and higher cost. On the other hand, trace NO is a vasodilator agent and employed in inhalation therapies for treating pulmonary hypertension in humans. Considering these factors, in the present study, a wet-type nonthermal plasma reactor, which can control NOx and nanoparticle emissions and generate NO, is investigated. The fundamental characteristics of the reactor are investigated. First, the experiment of nanoparticle removal is carried out. Collection efficiencies of over 99% are achieved for nanoparticles at 50 and 100 ml min‑1 of liquid flow rates. Second, experiments of NOx removal under air atmosphere and NOx generation under nitrogen atmosphere are carried out. NOx-removal efficiencies of over 95% under the air plasma are achieved in 50–200 ml min‑1 liquid flow rates. Moreover, under nitrogen plasma, NOx is generated, of which the major portion is NO. For example, NO concentration is 25 ppm, while NOx concentration is 31 ppm at 50 ml min‑1 liquid flow rate. Finally, experiments of NO generation under the nitrogen atmosphere with or without flowing water are carried out. When water flows on the inner surface of the reactor, approximately 14 ppm of NO is generated. Therefore, NO generation requires flowing water. It is considered that the reaction of N and OH, which is similar to the extended Zeldovich mechanism, could occur to induce NO formation. From these results, it is verified that the wet-type plasma reactor is useful for NOx removal and NO generation under nitrogen atmosphere with flowing water.

  4. Gold nanoparticle growth control - Implementing novel wet chemistry method on silicon substrate

    KAUST Repository

    Al-Ameer, Ammar; Katsiev, Habib; Sinatra, Lutfan; Hussein, Irshad; Bakr, Osman

    2013-01-01

    Controlling particle size, shape, nucleation, and self-assembly on surfaces are some of the main challenges facing electronic device fabrication. In this work, growth of gold nanoparticles over a wide range of sizes was investigated by using a novel

  5. Chemical Addressability of Ultraviolet-Inactivated Viral Nanoparticles (VNPs)

    Science.gov (United States)

    Rae, Chris; Koudelka, Kristopher J.; Destito, Giuseppe; Estrada, Mayra N.; Gonzalez, Maria J.; Manchester, Marianne

    2008-01-01

    Background Cowpea Mosaic Virus (CPMV) is increasingly being used as a nanoparticle platform for multivalent display of molecules via chemical bioconjugation to the capsid surface. A growing variety of applications have employed the CPMV multivalent display technology including nanoblock chemistry, in vivo imaging, and materials science. CPMV nanoparticles can be inexpensively produced from experimentally infected cowpea plants at high yields and are extremely stable. Although CPMV has not been shown to replicate in mammalian cells, uptake in mammalian cells does occur in vitro and in vivo. Thus, inactivation of the virus RNA genome is important for biosafety considerations, however the surface characteristics and chemical reactivity of the particles must be maintained in order to preserve chemical and structural functionality. Methodology/Principal Findings Short wave (254 nm) UV irradiation was used to crosslink the RNA genome within intact particles. Lower doses of UV previously reported to inactivate CPMV infectivity inhibited symptoms on inoculated leaves but did not prohibit systemic virus spread in plants, whereas higher doses caused aggregation of the particles and an increase in chemical reactivity further indicating broken particles. Intermediate doses of 2.0–2.5 J/cm2 were shown to maintain particle structure and chemical reactivity, and cellular binding properties were similar to CPMV-WT. Conclusions These studies demonstrate that it is possible to inactivate CPMV infectivity while maintaining particle structure and function, thus paving the way for further development of CPMV nanoparticles for in vivo applications. PMID:18830402

  6. Chemical addressability of ultraviolet-inactivated viral nanoparticles (VNPs.

    Directory of Open Access Journals (Sweden)

    Chris Rae

    2008-10-01

    Full Text Available Cowpea Mosaic Virus (CPMV is increasingly being used as a nanoparticle platform for multivalent display of molecules via chemical bioconjugation to the capsid surface. A growing variety of applications have employed the CPMV multivalent display technology including nanoblock chemistry, in vivo imaging, and materials science. CPMV nanoparticles can be inexpensively produced from experimentally infected cowpea plants at high yields and are extremely stable. Although CPMV has not been shown to replicate in mammalian cells, uptake in mammalian cells does occur in vitro and in vivo. Thus, inactivation of the virus RNA genome is important for biosafety considerations, however the surface characteristics and chemical reactivity of the particles must be maintained in order to preserve chemical and structural functionality.Short wave (254 nm UV irradiation was used to crosslink the RNA genome within intact particles. Lower doses of UV previously reported to inactivate CPMV infectivity inhibited symptoms on inoculated leaves but did not prohibit systemic virus spread in plants, whereas higher doses caused aggregation of the particles and an increase in chemical reactivity further indicating broken particles. Intermediate doses of 2.0-2.5 J/cm(2 were shown to maintain particle structure and chemical reactivity, and cellular binding properties were similar to CPMV-WT.These studies demonstrate that it is possible to inactivate CPMV infectivity while maintaining particle structure and function, thus paving the way for further development of CPMV nanoparticles for in vivo applications.

  7. Determination of chemical oxygen demand (COD) using an alternative wet chemical method free of mercury and dichromate.

    Science.gov (United States)

    Kolb, Marit; Bahadir, Müfit; Teichgräber, Burkhard

    2017-10-01

    Worldwide, the standard methods for the determination of the important wastewater parameter chemical oxygen demand (COD) are still based on the use of the hazardous chemicals, mercury sulfate and chromium(VI). However, due to their properties they are meanwhile classified as "priority pollutants" and shall be phased out or banned in the frame of REACH (current European Chemical Law: Registration, Evaluation, Authorization and restriction of Chemicals) by the European Union. Hence, a new wet-chemical method free of mercury and chromium(VI) was developed. Manganese(III) was used as oxidant and silver nitrate for the removal of chloride ions. The quantification was performed by back titration of manganese(III) with iron(II) as done in the standard method. In order to minimize losses of organic substances during the precipitation of silver chloride, suspended and colloid organic matter had to be separated by precipitation of aluminum hydroxide in a first step. In these cases, two fractions, one of the suspended and colloid matters and a second of the dissolved organic substances, are prepared and oxidized separately. The method was tested with potassium hydrogen phthalate (KHP) as conventional COD reference substance and different types of wastewater samples. The oxidation of KHP was reproducible in a COD range of 20-500 mg/L with a mean recovery rate of 88.7% in comparison to the standard COD method (DIN 38409-41). Also in presence of 1000 mg/L chloride a recovery rate of 84.1% was reached. For a series of industrial and municipal wastewater samples a high correlation (R 2  = 0.9935) to the standard method with a mean recovery rate of 78.1% (±5.2%) was determined. Even though the results of the new method are not 100% of the standard method, its high correlation to the standard method and reproducibility offers an environmentally benign alternative method with no need to purchase new laboratory equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Chemical sensors based on molecularly modified metallic nanoparticles

    International Nuclear Information System (INIS)

    Haick, Hossam

    2007-01-01

    This paper presents a concise, although admittedly non-exhaustive, didactic review of some of the main concepts and approaches related to the use of molecularly modified metal nanoparticles in or as chemical sensors. This paper attempts to pull together different views and terminologies used in sensors based on molecularly modified metal nanoparticles, including those established upon electrochemical, optical, surface Plasmon resonance, piezoelectric and electrical transduction approaches. Finally, this paper discusses briefly the main advantages and disadvantages of each of the presented class of sensors. (review article)

  9. Chemical phase analysis of seed mediated synthesized anisotropic silver nanoparticles

    International Nuclear Information System (INIS)

    Bharti, Amardeep; Goyal, Navdeep; Singh, Suman; Singla, M. L.

    2015-01-01

    Noble-metal nanoparticles are of great interest because of its broad applications almost in every stream (i.e. biology, chemistry and engineering) due to their unique size/shape dependant properties. In this paper, chemical phase of seed mediated synthesized anisotropic silver nanoparticle (AgNPs) has been investigated via fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). These nanaoparticles were synthesized by seed-growth method controlled by urea and dextrose results to highly stable 12-20 nm particle size revealed by zeta potential and transmission electron microscopy (TEM)

  10. Comparison of wet-only and bulk deposition at Chiang Mai (Thailand) based on rainwater chemical composition

    Science.gov (United States)

    Chantara, Somporn; Chunsuk, Nawarut

    The chemical composition of 122 rainwater samples collected daily from bulk and wet-only collectors in a sub-urban area of Chiang Mai (Thailand) during August 2005-July 2006 has been analyzed and compared to assess usability of a cheaper and less complex bulk collector over a sophisticated wet-only collector. Statistical analysis was performed on log-transformed daily rain amount and depositions of major ions for each collector type. The analysis of variance (ANOVA) test revealed that the amount of rainfall collected from a rain gauge, bulk collector and wet-only collector showed no significant difference ( ∝=0.05). The volume weight mean electro-conductivity (EC) values of bulk and wet-only samples were 0.69 and 0.65 mS/m, respectively. The average pH of the samples from both types of collectors was 5.5. Scatter plots between log-transformed depositions of specific ions obtained from bulk and wet-only samples showed high correlation ( r>0.91). Means of log-transformed bulk deposition were 14% (Na + and K +), 13% (Mg 2+), 7% (Ca 2+), 4% (NO 3-), 3% (SO 42- and Cl -) and 2% (NH 4+) higher than that of wet-only deposition. However, multivariate analysis of variance (MANOVA) revealed that ion depositions obtained from bulk and wet-only collectors were not significantly different ( ∝=0.05). Therefore, it was concluded that a bulk collector can be used instead of a wet-only collector in a sub-urban area.

  11. Chemically functionalized gold nanoparticles: Synthesis, characterization, and applications

    Science.gov (United States)

    Daniel, Weston Lewis

    This thesis focuses on the development and application of gold nanoparticle based detection systems and biomimetic structures. Each class of modified nanoparticle has properties that are defined by its chemical moieties that interface with solution and the gold nanoparticle core. In Chapter 2, a comparison of the biomolecular composition and binding properties of various preparations of antibody oligonucleotide gold nanoparticle conjugates is presented. These constructs differed significantly in terms of their structure and binding properties. Chapter 3 reports the use of electroless gold deposition as a light scattering signal enhancer in a multiplexed, microarray-based scanometric immunoassay using the gold nanoparticle probes evaluated in Chapter 2. The use of gold development results in greater signal enhancement than the typical silver development, and multiple rounds of metal development were found to increase the resulting signal compared to one development. Chapter 4 describes an amplified scanometric detection method for human telomerase activity. Gold nanoparticles functionalized with specific oligonucleotide sequences can efficiently capture telomerase enzymes and subsequently be elongated. Both the elongated and unmodified oligonucleotide sequences are simultaneously measured. At low telomerase concentrations, elongated strands cannot be detected, but the unmodified sequences, which come from the same probe particles, can be detected because their concentration is higher, providing a novel form of amplification. Chapter 5 reports the development of a novel colorimetric nitrite and nitrate ion assay based upon gold nanoparticle probes functionalized with Griess reaction reagents. This assay takes advantage of the distance-dependent plasmonic properties of the gold nanoparticles and the ability of nitrite ion to facilitate the cross coupling of novel nanoparticle probes. The assay works on the concept of a kinetic end point and can be triggered at the EPA

  12. CuO nanostructures on copper foil by a simple wet chemical route at room temperature

    International Nuclear Information System (INIS)

    Jana, S.; Das, S.; Das, N.S.; Chattopadhyay, K.K.

    2010-01-01

    Uniform CuO nanostructures have been synthesized on copper foil substrates by oxidation of Cu in alkaline condition by a simple wet chemical route at room temperature. By controlling the alkaline condition (pH value) different CuO nanostructures like nanoneedles, self-assembled nanoflowers and staking of flake-like structures were achieved. The phase formation and the composition of the films were characterized by X-ray diffraction and energy dispersive analysis of X-ray studies. X-ray photoelectron spectroscopic studies indicated that the samples were composed of CuO. The morphologies of the films were investigated by scanning electron microscopy. A possible growth mechanism is also proposed here. Band gap energies of the nanostructures were determined from the optical reflectance spectra. The different CuO nanostructures showed good electron field emission properties with turn-on fields in the range 6-11.3 V μm -1 . The field emission current was significantly affected by the morphologies of the CuO films.

  13. Bioceramics synthesis of hydroxyapatite from red snapper fish scales biowaste using wet chemical precipitation route

    Science.gov (United States)

    Ulfyana, D.; Anugroho, F.; Sumarlan, S. H.; Wibisono, Y.

    2018-03-01

    Fish scales biowaste contain high collagens and calcium phosphates, therefore have considerable potential as raw material for value-added biomaterial such as hydroxyapatite (HAp). HAp is the main constituent component of hard tissue such as bone and teeth in the human body and is known as bioceramic materials. In this work, wet chemical precipitation method was used to syntesize HAp from Red Snapper Fish (Lutjanus campechanus) Scales. Two variations of calcination temperatures of 600°C (FHAp1) and 800°C (FHAp2) were conducted for 5 hours. The results showed calcium content from biowaste of red snapper fish scale was 83.62%. FTIR result shows that PO4 3-, OH-, and CO3 2- functional groups presence as indicates the formation of HAp. XRD result showed the degree of crystallinity for FHAp1 and FHAp2 were 75.52% and 79.20%, respectively. The degree of crystallinity is in accordance with ISO 13779-2:2000 standard in which the minimum degree of crystallinity of hydroxyapatite used for biomedical materials is 45%. Finally, Particle Size Analyzer (PSA) results show that the particle size distribution is evenly distributed, with the size of micro-scale hydroxyapatite particles, ranging from 5.76 μm to 132.64 μm.

  14. Wet chemical passivation of YBa2Cu3O(7-x)

    Science.gov (United States)

    Vasquez, R. P.; Hunt, B. D.; Foote, M. C.

    1990-01-01

    Wet chemical techniques are described for treatment of YBa2Cu3O(7-x) surfaces, which result in the formation of native compounds known to have little or no reactivity to water. Suitable native compounds include CuI, BaSO4, CuS, Cu2S, YF3, and the oxalates. Formation of surface layers in which these nonreactive native compounds are major constituents is verified with X-ray photoelectron spectroscopy (XPS) measurements on YBa2Cu3O(7-x) films treated with dilute solutions of HI, H2SO4, Na2S, HF, or H2C2O4. No significant changes are observed in the XPS spectra when the sulfide, sulfate, or oxalate films are dipped in water, while the iodide and fluoride films show evidence of reaction with water. X-ray diffraction measurements show that the superconducting phase is absent in the sulfide film, but is unaffected by the oxalate and sulfate treatments.

  15. Tailoring Novel PTFE Surface Properties: Promoting Cell Adhesion and Antifouling Properties via a Wet Chemical Approach.

    Science.gov (United States)

    Gabriel, Matthias; Niederer, Kerstin; Becker, Marc; Raynaud, Christophe Michel; Vahl, Christian-Friedrich; Frey, Holger

    2016-05-18

    Many biomaterials used for tissue engineering applications lack cell-adhesiveness and, in addition, are prone to nonspecific adsorption of proteins. This is especially important for blood-contacting devices such as vascular grafts and valves where appropriate surface properties should inhibit the initial attachment of platelets and promote endothelial cell colonization. As a consequence, the long-term outcome of the implants would be improved and the need for anticoagulation therapy could be reduced or even abolished. Polytetrafluoroethylene (PTFE), a frequently used polymer for various medical applications, was wet-chemically activated and subsequently modified by grafting the endothelial cell (EC) specific peptide arginine-glutamic acid-aspartic acid-valine (REDV) using a bifunctional polyethylene glycol (PEG)-spacer (known to reduce platelet and nonspecific protein adhesion). Modified and control surfaces were both evaluated in terms of EC adhesion, colonization, and the attachment of platelets. In addition, samples underwent bacterial challenges. The results strongly suggested that PEG-mediated peptide immobilization renders PTFE an excellent substrate for cellular growth while simultaneously endowing the material with antifouling properties.

  16. Zintl Clusters as Wet-Chemical Precursors for Germanium Nanomorphologies with Tunable Composition.

    Science.gov (United States)

    Bentlohner, Manuel M; Waibel, Markus; Zeller, Patrick; Sarkar, Kuhu; Müller-Buschbaum, Peter; Fattakhova-Rohlfing, Dina; Fässler, Thomas F

    2016-02-12

    [Ge9](4-) Zintl clusters are used as soluble germanium source for a bottom-up fabrication of Ge nanomorphologies such as inverse opal structures with tunable composition. The method is based on the assembly and oxidation of [Ge9 ](4-) clusters in a template mold using SiCl4 , GeCl4 , and PCl3 leading to Si and P-containing Ge phases as shown by X-ray diffraction, Raman spectroscopy, and energy-dispersive X-ray analysis. [Ge9](4-) clusters are retained using ethylenediamine (en) as a transfer medium to a mold after removal of the solvent if water is thoroughly excluded, but are oxidized to amorphous Ge in presence of water traces. (1)H NMR spectroscopy reveals the oxidative deprotonation of en by [Ge9](4-). Subsequent annealing leads to crystalline Ge. As an example for wet-chemical synthesis of complex Ge nanomorphologies, we describe the fabrication of undoped and P-doped inverse opal-structured Ge films with a rather low oxygen contents. The morphology of the films with regular volume porosity is characterized by SEM, TEM, and grazing incidence small-angle X-ray scattering. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Wet-chemical etching of atom probe tips for artefact free analyses of nanoscaled semiconductor structures.

    Science.gov (United States)

    Melkonyan, D; Fleischmann, C; Veloso, A; Franquet, A; Bogdanowicz, J; Morris, R J H; Vandervorst, W

    2018-03-01

    We introduce an innovative specimen preparation method employing the selectivity of a wet-chemical etching step to improve data quality and success rates in the atom probe analysis of contemporary semiconductor devices. Firstly, on the example of an SiGe fin embedded in SiO 2 we demonstrate how the selective removal of SiO 2 from the final APT specimen significantly improves accuracy and reliability of the reconstructed data. With the oxide removal, we eliminate the origin of shape artefacts, i.e. the formation of a non-hemispherical tip shape, that are typically observed in the reconstructed volume of complex systems. Secondly, using the same approach, we increase success rates to ∼90% for the damage-free, 3D site-specific localization of short (250 nm), vertical Si nanowires at the specimen apex. The impact of the abrupt emitter radius change that is introduced by this specimen preparation method is evaluated as being minor using field evaporation simulation and comparison of different reconstruction schemes. The Ge content within the SiGe fin as well as the 3D boron distribution in the Si NW as resolved by atom probe analysis are in good agreement with TEM/EDS and ToF-SIMS analysis, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Concurrent production of biodiesel and chemicals through wet in situ transesterification of microalgae.

    Science.gov (United States)

    Im, Hanjin; Kim, Bora; Lee, Jae W

    2015-10-01

    This work addresses an unprecedented way of co-producing biodiesel (FAEE) and valuable chemicals of ethyl levulinate (EL), ethyl formate (EF) and diethyl ether (DEE) from wet in situ transesterification of microalgae. EL, EF, and DEE were significantly produced up to 23.1%, 10.3%, and 52.1% of the maximum FAEE mass with the FAEE yield higher than 90% at 125 °C. Experiments to elucidate a detailed route of EL and EF synthesis were fulfilled and it was found that its main route to the production of EL and EF was the acid hydrolysis of algal cells and esterification with ethanol. To investigate the effect of reaction variables on the products yields, comprehensive experiments were carried out with varying temperatures, solvent and alcohol volumes, moisture contents and catalyst amounts. Coproduction of DEE, EL, EF and FAEE can contribute to elevating the economic feasibility of microalgae-based biodiesel supply chain. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Synthesis of ZnO micro-pompons by soft template-directed wet chemical method and their application in electrochemical biosensors

    International Nuclear Information System (INIS)

    Zhou, Yu; Wang, Lei; Ye, Zhizhen; Zhao, Minggang; Huang, Jingyun

    2014-01-01

    Highlights: •ZnO micro-pompons (MPs) are synthesized by a controlled soft template-directed route. •ZnO MPs are composed of radial robust nanowires built of numerous nanoparticles. •The structure is ideal for the immobilization of enzymes to maintain their activity. •ZnO MPs are favorable for electron transfer and liquid mobilization. •Good performance of H 2 O 2 biosensor indicates ZnO MPs are promising in biosensing. -- Abstract: ZnO micro-pompons are fabricated by a controlled synthesis route via a soft template-directed wet chemical method followed by a subsequent calcination in air. The achieved ZnO micro-pompons with several hundred micrometers in diameter are composed of a great number of robust nanowires built of numerous nanoparticles. This unique structure is accessible for enzymes to sequester or bind, and the tightly connected nanoparticles facilitate the transmission of electrons, what's more, the large spaces between the nanowires are favorable for the mobilization of the liquid with target substance. In addition, the high electron communication features of ZnO and the tightly connected nanoparticles of the structure also promote the electron transfer between the active sites of proteins and the electrode. The enzymatic electrode fabricated with Horseradish peroxidase immobilized on ZnO micro-pompons along with chitosan covering outside exhibits excellent response for detecting H 2 O 2 with a wide linear range of 0.2–3.4 mM and a high sensitivity of 1395.64 (μA/mM cm 2 ), indicating a great potential in fabricating electrochemical biosensors

  20. Wet-chemical passivation of InAs: toward surfaces with high stability and low toxicity.

    Science.gov (United States)

    Jewett, Scott A; Ivanisevic, Albena

    2012-09-18

    In a variety of applications where the electronic and optical characteristics of traditional, siliconbased materials are inadequate, recently researchers have employed semiconductors made from combinations of group III and V elements such as InAs. InAs has a narrow band gap and very high electron mobility in the near-surface region, which makes it an attractive material for high performance transistors, optical applications, and chemical sensing. However, silicon-based materials remain the top semiconductors of choice for biological applications, in part because of their relatively low toxicity. In contrast to silicon, InAs forms an unstable oxide layer under ambient conditions, which can corrode over time and leach toxic indium and arsenic components. To make InAs more attractive for biological applications, researchers have investigated passivation, chemical and electronic stabilization, of the surface by adlayer adsorption. Because of the simplicity, low cost, and flexibility in the type of passivating molecule used, many researchers are currently exploring wet-chemical methods of passivation. This Account summarizes much of the recent work on the chemical passivation of InAs with a particular focus on the chemical stability of the surface and prevention of oxide regrowth. We review the various methods of surface preparation and discuss how crystal orientation affects the chemical properties of the surface. The correct etching of InAs is critical as researchers prepare the surface for subsequent adlayer adsorption. HCl etchants combined with a postetch annealing step allow the tuning of the chemical properties in the near-surface region to either arsenic- or indium-rich environments. Bromine etchants create indium-rich surfaces and do not require annealing after etching; however, bromine etchants are harsh and potentially destructive to the surface. The simultaneous use of NH(4)OH etchants with passivating molecules prevents contact with ambient air that can

  1. Chemical changes in carbon Nanotube-Nickel/Nickel Oxide Core/Shell nanoparticle heterostructures treated at high temperatures

    International Nuclear Information System (INIS)

    Chopra, Nitin; McWhinney, Hylton G.; Shi Wenwu

    2011-01-01

    Heterostructures composed of carbon nanotube (CNT) coated with Ni/NiO core/shell nanoparticles (denoted as CNC heterostructures) were synthesized in a wet-chemistry and single-step synthesis route involving direct nucleation of nanoparticles on CNT surface. Two different aspects of CNC heterostructures were studied here. First, it was observed that the nanoparticle coatings were more uniform on the as-produced and non-purified CNTs compared to purified (or acid treated) CNTs. These heterostructures were characterized using electron microscopy, Raman spectroscopy, and energy dispersive spectroscopy. Second, thermal stability of CNC heterostructures was studied by annealing them in N 2 -rich (O 2 -lean) environment between 125 and 750 deg. C for 1 h. A detailed X-ray photoelectron spectroscopy and Raman spectroscopy analysis was performed to evaluate the effects of annealing temperatures on chemical composition, phases, and stability of the heterostructures. It was observed that the CNTs present in the heterostructures completely decomposed and core Ni nanoparticle oxidized significantly between 600 and 750 deg. C. - Research Highlights: → Heterostructures composed of CNTs coated with Ni/NiO core/shell nanoparticles. → Poor nanoparticle coverage on purified CNT surface compared to non-purified CNTs. → CNTs in heterostructures decompose between 600 and 750 deg. C in N 2 -rich atmosphere. → Metallic species in heterostructures were oxidized at higher temperatures.

  2. Mixing and transport during pharmaceutical twin-screw wet granulation: experimental analysis via chemical imaging.

    Science.gov (United States)

    Kumar, Ashish; Vercruysse, Jurgen; Toiviainen, Maunu; Panouillot, Pierre-Emmanuel; Juuti, Mikko; Vanhoorne, Valérie; Vervaet, Chris; Remon, Jean Paul; Gernaey, Krist V; De Beer, Thomas; Nopens, Ingmar

    2014-07-01

    Twin-screw granulation is a promising continuous alternative for traditional batch high shear wet granulation (HSWG). The extent of HSWG in a twin screw granulator (TSG) is greatly governed by the residence time of the granulation materials in the TSG and degree of mixing. In order to determine the residence time distribution (RTD) and mixing in TSG, mostly visual observation and particle tracking methods are used, which are either inaccurate and difficult for short RTD, or provide an RTD only for a finite number of preferential tracer paths. In this study, near infrared chemical imaging, which is more accurate and provides a complete RTD, was used. The impact of changes in material throughput (10-17 kg/h), screw speed (500-900 rpm), number of kneading discs (2-12) and stagger angle (30-90°) on the RTD and axial mixing of the material was characterised. The experimental RTD curves were used to calculate the mean residence time, mean centred variance and the Péclet number to determine the axial mixing and predominance of convective over dispersive transport. The results showed that screw speed is the most influential parameter in terms of RTD and axial mixing in the TSG and established a significant interaction between screw design parameters (number and stagger angle of kneading discs) and the process parameters (material throughput and number of kneading discs). The results of the study will allow the development and validation of a transport model capable of predicting the RTD and macro-mixing in the TSG. These can later be coupled with a population balance model in order to predict granulation yields in a TSG more accurately. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Antireflective surface structures in glass by self-assembly of SiO2 nanoparticles and wet etching.

    Science.gov (United States)

    Maier, Thomas; Bach, David; Müllner, Paul; Hainberger, Rainer; Brückl, Hubert

    2013-08-26

    We describe the fabrication of an antireflective surface structure with sub-wavelength dimensions on a glass surface using scalable low-cost techniques involving sol-gel coating, thermal annealing, and wet chemical etching. The glass surface structure consists of sand dune like protrusions with 250 nm periodicity and a maximum peak-to-valley height of 120 nm. The antireflective structure increases the transmission of the glass up to 0.9% at 700 nm, and the transmission remains enhanced over a wide spectral range and for a wide range of incident angles. Our measurements reveal a strong polarization dependence of the transmission change.

  4. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    Energy Technology Data Exchange (ETDEWEB)

    Angermann, Heike, E-mail: angermann@helmholtz-berlin.de

    2014-09-01

    Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D{sub it}(E), and density D{sub it,min} of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly

  5. Wetting, Solubility and Chemical Characteristics of Plasma-Polymerized 1-Isopropyl-4-Methyl-1,4-Cyclohexadiene Thin Films

    Directory of Open Access Journals (Sweden)

    Jakaria Ahmad

    2014-07-01

    Full Text Available Investigations on the wetting, solubility and chemical composition of plasma polymer thin films provide an insight into the feasibility of implementing these polymeric materials in organic electronics, particularly where wet solution processing is involved. In this study, thin films were prepared from 1-isopropyl-4-methyl-1,4-cyclohexadiene (γ-Terpinene using radio frequency (RF plasma polymerization. FTIR showed the polymers to be structurally dissimilar to the original monomer and highly cross-linked, where the loss of original functional groups and the degree of cross-linking increased with deposition power. The polymer surfaces were hydrocarbon-rich, with oxygen present in the form of O–H and C=O functional groups. The oxygen content decreased with deposition power, with films becoming more hydrophobic and, thus, less wettable. The advancing and receding contact angles were investigated, and the water advancing contact angle was found to increase from 63.14° to 73.53° for thin films prepared with an RF power of 10 W to 75 W. The wetting envelopes for the surfaces were constructed to enable the prediction of the surfaces’ wettability for other solvents. The effect of roughness on the wetting behaviour of the films was insignificant. The polymers were determined to resist solubilization in solvents commonly used in the deposition of organic semiconducting layers, including chloroform and chlorobenzene, with higher stability observed in films fabricated at higher RF power.

  6. The Luminescence of CH3 NH3 PbBr3 Perovskite Nanoparticles Crests the Summit and Their Photostability under Wet Conditions is Enhanced.

    Science.gov (United States)

    Gonzalez-Carrero, Soranyel; Francés-Soriano, Laura; González-Béjar, María; Agouram, Saïd; Galian, Raquel E; Pérez-Prieto, Julia

    2016-10-01

    CH 3 NH 3 PbBr 3 perovskite nanoparticles (P AD ) are prepared with a photoluminescence quantum yield of ≈100% in air atmosphere by using the quasi-spherical shaped 2-adamantylammonium bromide (ADBr) as the only capping ligand. The photostability under wet conditions of this kind of nanoparticles is enhanced by using cucurbit[7]uril-adamantylammonium (AD@CB) host-guest complexes as the capping ligand. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Evolution of the magnetic properties of Co10Cu90 nanoparticles prepared by wet chemistry with thermal annealing.

    Science.gov (United States)

    García, I; Echeberria, J; Kakazei, G N; Golub, V O; Saliuk, O Y; Ilyn, M; Guslienko, K Y; González, J M

    2012-09-01

    Nanoparticles of Co10Cu90 alloy have been prepared by sonochemical wet method. According to transmission electron microscopy, bimetallic particles with typical diameter of 50-100 nm consisting of nanocrystallites with average diameter of 15-20 nm were obtained. The samples were annealed at 300 degrees C and 450 degrees C. Zero field cooled and field cooled temperature dependences of magnetization in the temperature range of 5-400 K at 50 Oe, as well as magnetization hysteresis loops at 15, 100 and 305 K were measured by vibrating sample magnetometry. Presence of antiferromagnetic phase, most probably of the oxide Co3O4, was observed in as-prepared sample. The lowest coercivity was found for the CoCu sample annealed at-300 degrees C, whereas for as prepared sample and the one annealed at 450 degrees C it was significantly higher. The samples were additionally probed by continuous wave ferromagnetic resonance at room, temperature using a standard X-band electron spin resonance spectrometer. A good correspondence between evolution of the coercivity and the microwave resonance fields with annealing temperature was observed.

  8. Low-temperature wafer direct bonding of silicon and quartz glass by a two-step wet chemical surface cleaning

    Science.gov (United States)

    Wang, Chenxi; Xu, Jikai; Zeng, Xiaorun; Tian, Yanhong; Wang, Chunqing; Suga, Tadatomo

    2018-02-01

    We demonstrate a facile bonding process for combining silicon and quartz glass wafers by a two-step wet chemical surface cleaning. After a post-annealing at 200 °C, strong bonding interfaces with no defects or microcracks were obtained. On the basis of the detailed surface and bonding interface characterizations, the bonding mechanism was explored and discussed. The amino groups terminated on the cleaned surfaces might contribute to the bonding strength enhancement during the annealing. This cost-effective bonding process has great potentials for silicon- and glass-based heterogeneous integrations without requiring a vacuum system.

  9. A simple wet chemical method for the determination of cation stoichiometry of YBa2Cu3O7-d

    International Nuclear Information System (INIS)

    Sahasranaman, S.; Premila, M.; Sreedharan, O.M.

    1996-01-01

    A comprehensive wet chemical procedure for the rapid analysis of yttrium, barium and copper ions in dilute HNO 3 medium has been developed to facilitate a precise and accurate determination of cation non-stoichiometry in high temperature ceramic superconducting materials Y 1±x Ba 2±y Cu 3±z O 7-d . The ease of analysis for copper by electrogravimetry and of yttrium and barium by a complexometric titration of the same aliquot against complexone III using arsenazo I as the indicator under appropriate pH has been demonstrated with the help of individual standard solutions and with synthetic mixtures. (author)

  10. Versatile Optimization of Chemical Ordering in Bimetallic Nanoparticles

    KAUST Repository

    Ková cs, Gá bor; Kozlov, Sergey M.; Neyman, Konstantin M.

    2017-01-01

    Chemical ordering in bimetallic nanocrystallites can now be efficiently determined by density-functional calculations with the help of topological energy expressions. Herein, we deal with extending the usage of that computational scheme. We show that it enables one to structurally characterize bimetallic nanoparticles of less regular shapes than previously studied magic-type particles. In fcc Pd–Au particles of different shapes (cuboctahedral Pd58Au58, C3v Pd61Au61, cubic Pd68Au67, and truncated octahedral Pd70Au70), we identify the surface segregation of gold as the driving force to the lowest-energy chemical ordering. We applied the calculated descriptor values quantifying the segregation propensity of Au and energies of Pd–Au bonds in these ∼1.5 nm large particles to optimize and analyze the chemical ordering in 3.7–6 nm large Pd–Au particles. We also discuss how to predict the chemical ordering in nanoalloys at elevated temperatures. The present study paves the way to advanced structural investigations of nanoalloys to substantially accelerate their knowledge-driven engineering and manufacturing.

  11. Versatile Optimization of Chemical Ordering in Bimetallic Nanoparticles

    KAUST Repository

    Kovács, Gábor

    2017-01-05

    Chemical ordering in bimetallic nanocrystallites can now be efficiently determined by density-functional calculations with the help of topological energy expressions. Herein, we deal with extending the usage of that computational scheme. We show that it enables one to structurally characterize bimetallic nanoparticles of less regular shapes than previously studied magic-type particles. In fcc Pd–Au particles of different shapes (cuboctahedral Pd58Au58, C3v Pd61Au61, cubic Pd68Au67, and truncated octahedral Pd70Au70), we identify the surface segregation of gold as the driving force to the lowest-energy chemical ordering. We applied the calculated descriptor values quantifying the segregation propensity of Au and energies of Pd–Au bonds in these ∼1.5 nm large particles to optimize and analyze the chemical ordering in 3.7–6 nm large Pd–Au particles. We also discuss how to predict the chemical ordering in nanoalloys at elevated temperatures. The present study paves the way to advanced structural investigations of nanoalloys to substantially accelerate their knowledge-driven engineering and manufacturing.

  12. Size-controlled synthesis of transition metal nanoparticles through chemical and photo-chemical routes

    Science.gov (United States)

    Tangeysh, Behzad

    The central objective of this work is developing convenient general procedures for controlling the formation and stabilization of nanoscale transition metal particles. Contemporary interest in developing alternative synthetic approaches for producing nanoparticles arises in large part from expanding applications of the nanomaterials in areas such as catalysis, electronics and medicine. This research focuses on advancing the existing nanoparticle synthetic routes by using a new class of polymer colloid materials as a chemical approach, and the laser irradiation of metal salt solution as a photo-chemical method to attain size and shape selectivity. Controlled synthesis of small metal nanoparticles with sizes ranging from 1 to 5nm is still a continuing challenge in nanomaterial synthesis. This research utilizes a new class of polymer colloid materials as nano-reactors and protective agents for controlling the formation of small transition metal nanoparticles. The polymer colloid particles were formed from cross-linking of dinegatively charged metal precursors with partially protonated poly dimethylaminoethylmethacrylate (PDMAEMA). Incorporation of [PtCl6]2- species into the colloidal particles prior to the chemical reduction was effectively employed as a new strategy for synthesis of unusually small platinum nanoparticles with narrow size distributions (1.12 +/-0.25nm). To explore the generality of this approach, in a series of proof-of-concept studies, this method was successfully employed for the synthesis of small palladium (1.4 +/-0.2nm) and copper nanoparticles (1.5 +/-0.6nm). The polymer colloid materials developed in this research are pH responsive, and are designed to self-assemble and/or disassemble by varying the levels of protonation of the polymer chains. This unique feature was used to tune the size of palladium nanoparticles in a small range from 1nm to 5nm. The procedure presented in this work is a new convenient room temperature route for synthesis of

  13. Effect of Synthesis Parameters on the Structure and Magnetic Properties of Magnetic Manganese Ferrite/Silver Composite Nanoparticles Synthesized by Wet Chemistry Method

    DEFF Research Database (Denmark)

    Huy, L.T.; Tam, L.T.; Phan, V.N.

    2016-01-01

    In the present work, magnetic manganese ferrite/silver (MnFe2O4-Ag) composite nanoparticles were synthesized by wet chemistry method. This synthesis process consists of two steps: first, the seed of manganese ferrite nanoparticles (MnFe2O4 NPs) was prepared by a coprecipitationmethod; second......, growth of silver nanoparticles (AgNPs) on the MnFe2O4 seed by modified photochemical reaction. We have conducted systematically the effects of synthesis parameters such as pH value, synthesis time, precursor salts concentration, mass ratio and stabilizing agents on the structure and magnetic properties......-prepared MnFe2O4-Ag magnetic nanocomposites display excellent properties of high crystallinity, long-term aggregation stability in aqueous medium, large saturation magnetization in the range of 15-20 emu/g, and small sizes of Ag-NPs similar to 20 nm. These exhibited properties made the MnFe2O4-Ag...

  14. Wet oxidative degradation of cellulosic wastes 5- chemical and thermal properties of the final waste forms

    International Nuclear Information System (INIS)

    Eskander, S.B.; Saleh, H.M.

    2002-01-01

    In this study, the residual solution arising from the wet oxidative degradation of solid organic cellulosic materials, as one of the component of radioactive solid wastes, using hydrogen peroxide as oxidant. Were incorporated into ordinary Portland cement matrix. Leaching as well as thermal characterizations of the final solidified waste forms were evaluated to meet the final disposal requirements. Factors, such as the amount of the residual solution incorporated, types of leachant. Release of different radionuclides and freezing-thaw treatment, that may affect the leaching characterization. Were studied systematically from the data obtained, it was found that the final solid waste from containing 35% residual solution in tap water is higher than that in ground water or sea water. Based on the data obtained from thermal analysis, it could be concluded that incorporating the residual solution form the wet oxidative degradation of cellulosic materials has no negative effect on the hydration of cement materials and consequently on the thermal stability of the final solid waste from during the disposal process

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

    Science.gov (United States)

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

    2017-02-01

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

  16. Recent advances in chemical functionalization of nanoparticles with biomolecules for analytical applications.

    Science.gov (United States)

    Oh, Ju-Hwan; Park, Do Hyun; Joo, Jang Ho; Lee, Jae-Seung

    2015-11-01

    The recent synthetic development of a variety of nanoparticles has led to their widespread application in diagnostics and therapeutics. In particular, the controlled size and shape of nanoparticles precisely determine their unique chemical and physical properties, which is highly attractive for accurate analysis of given systems. In addition to efforts toward controlling the synthesis and properties of nanoparticles, the surface functionalization of nanoparticles with biomolecules has been intensively investigated since the mid-1990s. The complicated yet programmable properties of biomolecules have proved to substantially enhance and enrich the novel functions of nanoparticles to achieve "smart" nanoparticle materials. In this review, the advances in chemical functionalization of four types of representative nanoparticle with DNA and protein molecules in the past five years are critically reviewed, and their future trends are predicted.

  17. Investigation of the Factors Influencing Volatile Chemical Fate During Steady-state Accretion on Wet-growing Hail

    Science.gov (United States)

    Michael, R. A.; Stuart, A. L.

    2007-12-01

    Phase partitioning during freezing affects the transport and distribution of volatile chemical species in convective clouds. This consequently can have impacts on tropospheric chemistry, air quality, pollutant deposition, and climate change. Here, we discuss the development, evaluation, and application of a mechanistic model for the study and prediction of volatile chemical partitioning during steady-state hailstone growth. The model estimates the fraction of a chemical species retained in a two-phase freezing hailstone. It is based upon mass rate balances over water and solute for accretion under wet-growth conditions. Expressions for the calculation of model components, including the rates of super-cooled drop collection, shedding, evaporation, and hail growth were developed and implemented based on available cloud microphysics literature. Solute fate calculations assume equilibrium partitioning at air-liquid and liquid-ice interfaces. Currently, we are testing the model by performing mass balance calculations, sensitivity analyses, and comparison to available experimental data. Application of the model will improve understanding of the effects of cloud conditions and chemical properties on the fate of dissolved chemical species during hail growth.

  18. Quantum chemical evaluation for the stability of liquid sodium containing titanium nanoparticles

    International Nuclear Information System (INIS)

    Suzuki, Ai; Inaba, Kenji; Ishizawa, Yukie; Miura, Ryuji; Hatakeyama, Nozomu; Miyamoto, Akira; Saito, Jun-ichi; Ara, Kuniaki

    2015-01-01

    Recently, liquid sodium containing titanium nanoparticles (LSnanop) have attracted considerable attention. In this study, suspension state of Ti nanoparticle in liquid sodium was quantum chemically evaluated. The atomic interaction between Ti nanoparticles and sodium atoms in the liquid sodium medium was investigated. There were some literatures which gained quantum chemical insight into a nanoparticle with the surrounding sodium atom. However, liquid sodium medium itself together with a Ti nanoparticle under the realistic temperature has not yet been investigated theoretically. To overcome the problem of conventional theoretical method, we applied computationally low-load Tight Binding Quantum Chemical Molecular Dynamics (TB-QCMD) calculation method to investigate the suspension state of the Ti nanoparticle in liquid sodium metal. (author)

  19. Effect of Chemical Stabilizers in Silver Nanoparticle Suspensions on Nanotoxicity

    International Nuclear Information System (INIS)

    Bae, Eun Joo; Park, Hee Jin; Park, Jun Su; Yoon, Je Yong; Yi, Jong Heop; Kim, Young Hun; Choi, Kyung Hee

    2011-01-01

    Colloidal silver nanoparticles (AgNPs) have been commercialized as the typically stabilized form via the addition of a variety of surfactants or polymers. Herein, to examine the effects of stabilizing AgNPs in suspension, we modified the surface of bare AgNPs with four type of surfactants (NaDDBS, SDS, TW80, CTAB) and polymers (PVP, PAA, PAH, CMC). The modified AgNPs was applied to compare suspension stability and nanotoxicity test using Escherichia coli (E. coli) as a model organism. Modification of AgNPs surface using chemical stabilizer may be not related with molecular weight, but chemical structure such as ionic state and functional group of stabilizer. In this study, it is noteworthy that AgNPs modified with a cationic stabilizer (CTAB, PAH) were importantly toxic to E. coli, rather than anionic stabilizers (NaDDBS, SDS). Comparing similar anionic stabilizer, i.e., NaDDBS and SDS, the result showed that lipophilicity of chemical structure can affect on E. coli, because NaDDBS, which contains a lipophilic benzene ring, accelerated the cytotoxicity of AgNPs. Interestingly, none of the stabilizers tested, including biocompatible nonionic stabilizers (i.e., TW80 and cellulose) caused a reduction in AgNP toxicity. This showed that toxicity of AgNPs cannot be reduced using stabilizers

  20. Effect of Chemical Stabilizers in Silver Nanoparticle Suspensions on Nanotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Eun Joo; Park, Hee Jin; Park, Jun Su; Yoon, Je Yong; Yi, Jong Heop [Seoul National University, Seoul (Korea, Republic of); Kim, Young Hun [Kwangwoon University, Seoul (Korea, Republic of); Choi, Kyung Hee [National Institute of Environmental Research, Incheon (Korea, Republic of)

    2011-02-15

    Colloidal silver nanoparticles (AgNPs) have been commercialized as the typically stabilized form via the addition of a variety of surfactants or polymers. Herein, to examine the effects of stabilizing AgNPs in suspension, we modified the surface of bare AgNPs with four type of surfactants (NaDDBS, SDS, TW80, CTAB) and polymers (PVP, PAA, PAH, CMC). The modified AgNPs was applied to compare suspension stability and nanotoxicity test using Escherichia coli (E. coli) as a model organism. Modification of AgNPs surface using chemical stabilizer may be not related with molecular weight, but chemical structure such as ionic state and functional group of stabilizer. In this study, it is noteworthy that AgNPs modified with a cationic stabilizer (CTAB, PAH) were importantly toxic to E. coli, rather than anionic stabilizers (NaDDBS, SDS). Comparing similar anionic stabilizer, i.e., NaDDBS and SDS, the result showed that lipophilicity of chemical structure can affect on E. coli, because NaDDBS, which contains a lipophilic benzene ring, accelerated the cytotoxicity of AgNPs. Interestingly, none of the stabilizers tested, including biocompatible nonionic stabilizers (i.e., TW80 and cellulose) caused a reduction in AgNP toxicity. This showed that toxicity of AgNPs cannot be reduced using stabilizers.

  1. The contact angle of wetting of the solid phase of soil before and after chemical modification

    Directory of Open Access Journals (Sweden)

    Tyugai Zemfira

    2015-07-01

    Full Text Available Wettability of soil affects a wide variety of processes including infiltration, preferential flow and surface runoff. Wettability of surface is usually expressed in terms of contact angle (CA measurement. If the CA between liquid and solid surface is less than 90°, the surface is called hydrophilic, otherwise the surface is called hydrophobic. If the CA of water droplet on hydrophilic surface is in a range of 0-30° this surface is called superhydrophilic. In case of superhydrophobic surfaces the CA exceeds 150° that means that these surfaces are extremely difficult to wet. CA of wetting of mineral soil particles depends on the overlying organic and iron compounds. The object of study is a sample of the humus-accumulative horizon of typical chernozem (Kursk, Russia and two samples (horizons A1, B2 of red ferrallitic soils (Fr. Norfolk, NE Oceania. The soil samples were analyzed for organic carbon, forms of non-silicate iron and hydrophobic-hydrophilic composition of humic substances. CA of wetting was determined in the intact samples and after removal of organic matter (H2O2 treatment, amorphous and crystallized forms of iron. Static contact angles were determined with the sessile drop method using a digital goniometer (Drop Shape Analysis System, DSA100, Krüss GmbH, Hamburg, Germany. The contact angle was calculated by the Young–Laplace method (fitting of Young–Laplace equation to the drop shape. The measurements were repeated 10-15 times for every sample. Oxidation of organic matter (H2O2 treatment causes an increase in the values of CA of wetting (in chernozem from 9.3 to 28,0-29.5º, in ferrallitic soil from 18.0 − 27.3 to 22.4 − 33.4º. CA remained constant for chernozem and slightly decreased in the case of ferrallitic soil, when the removal of amorphous and crystallized forms of iron was performed on samples pretreated with H2O2. CA increase occurs after successive removal of nonsilicate forms of iron from soil samples of

  2. Microstructures, Mechanical Properties and Thermal Conductivities of W-0.5 wt.%TiC Alloys Prepared via Ball Milling and Wet Chemical Method

    Science.gov (United States)

    Lang, Shaoting; Yan, Qingzhi; Sun, Ningbo; Zhang, Xiaoxin; Ge, Changchun

    2017-10-01

    Two kinds of W-0.5 wt.%TiC alloys were prepared, one by ball milling and the other by the wet chemical method. For comparison, pure tungsten powders were chemically prepared and sintered by the same process. The microstructures, mechanical properties and thermal conductivities of the prepared samples were characterized. It has been found that the wet chemical method resulted in finer sizes and more uniform distribution of TiC particles in the sintered tungsten matrix than the ball milling method. The W-TiC alloy prepared by the wet chemical method achieved the highest bending strength (1065.72 MPa) among the samples. Further, it also exhibited obviously higher thermal conductivities in the temperature range of room temperature to 600°C than did the W-TiC alloy prepared by ball milling, but the differences in their thermal conductivities could be ignored in the range of 600-800°C.

  3. Weak ferromagnetism and exchange biasing in cobalt oxide nanoparticle systems

    NARCIS (Netherlands)

    Tomou, A; Gournis, D; Panagiotopoulos, [No Value; Huang, Y; Hadjipanayis, GC; Kooi, BJ; Panagiotopoulos, I.

    2006-01-01

    Cobalt oxide nanoparticle systems have been prepared by wet chemical processing involving the encapsulation of the nanoparticles by an organic ligand shell (oleic acid and oleylamine). CoO nanoparticles were easily prepared by this method, while the synthesis of the CoPt/CoO nanocomposites was

  4. CO gas sensing of CuO nanostructures, synthesized by an assisted solvothermal wet chemical route

    International Nuclear Information System (INIS)

    Aslani, Alireza; Oroojpour, Vahid

    2011-01-01

    CuO nanostructures with different morphologies and sizes were grown in a controlled manner using a simple low-temperature hydrothermal technique. By controlling the pH of reaction mixture, spherical nanoparticles and cloudlike CuO structures were synthesized at 100-150 o C with excellent efficiency. These CuO nanostructures have been tested for CO gas monitoring by depositing them as thick films on an interdigitated alumina substrate and evaluated the surface resistance of the deposited layer as a function of operating temperature and CO concentrations. The gas sensitivity tests have demonstrated that the CuO nanostructures, especially cloudlike morphology, exhibit high sensitivity to CO proving their applicability in gas sensors. The role of the nanostructure on the sensing properties of CuO is also discussed.

  5. Chemical and structural investigation of lipid nanoparticles: drug-lipid interaction and molecular distribution

    Energy Technology Data Exchange (ETDEWEB)

    Anantachaisilp, Suranan; Smith, Siwaporn Meejoo [Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400 (Thailand); Treetong, Alongkot; Ruktanonchai, Uracha Rungsardthong [National Nanotechnology Center, National Science and Technology Development Agency, 111 Thailand Science Park, Paholyothin Road, Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Pratontep, Sirapat [College of KMITL Nanotechnology, King Mongkut' s Institute of Technology Ladkrabang, Bangkok (Thailand); Puttipipatkhachorn, Satit, E-mail: uracha@nanotec.or.th [Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400 (Thailand)

    2010-03-26

    Lipid nanoparticles are a promising alternative to existing carriers in chemical or drug delivery systems. A key challenge is to determine how chemicals are incorporated and distributed inside nanoparticles, which assists in controlling chemical retention and release characteristics. This study reports the chemical and structural investigation of {gamma}-oryzanol loading inside a model lipid nanoparticle drug delivery system composed of cetyl palmitate as solid lipid and Miglyol 812 as liquid lipid. The lipid nanoparticles were prepared by high pressure homogenization at varying liquid lipid content, in comparison with the {gamma}-oryzanol free systems. The size of the lipid nanoparticles, as measured by the photon correlation spectroscopy, was found to decrease with increased liquid lipid content from 200 to 160 nm. High-resolution proton nuclear magnetic resonance ({sup 1}H-NMR) measurements of the medium chain triglyceride of the liquid lipid has confirmed successful incorporation of the liquid lipid in the lipid nanoparticles. Differential scanning calorimetric and powder x-ray diffraction measurements provide complementary results to the {sup 1}H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of {gamma}-oryzanol inside the lipid nanoparticles, the {sup 1}H-NMR revealed that the chemical shifts of the liquid lipid in {gamma}-oryzanol loaded systems were found at rather higher field than those in {gamma}-oryzanol free systems, suggesting incorporation of {gamma}-oryzanol in the liquid lipid. In addition, the phase-separated structure was observed by atomic force microscopy for lipid nanoparticles with 0% liquid lipid, but not for lipid nanoparticles with 5 and 10% liquid lipid. Raman spectroscopic and mapping measurements further revealed preferential incorporation of {gamma}-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models

  6. Chemical and structural investigation of lipid nanoparticles: drug-lipid interaction and molecular distribution

    Science.gov (United States)

    Anantachaisilp, Suranan; Meejoo Smith, Siwaporn; Treetong, Alongkot; Pratontep, Sirapat; Puttipipatkhachorn, Satit; Rungsardthong Ruktanonchai, Uracha

    2010-03-01

    Lipid nanoparticles are a promising alternative to existing carriers in chemical or drug delivery systems. A key challenge is to determine how chemicals are incorporated and distributed inside nanoparticles, which assists in controlling chemical retention and release characteristics. This study reports the chemical and structural investigation of γ-oryzanol loading inside a model lipid nanoparticle drug delivery system composed of cetyl palmitate as solid lipid and Miglyol 812® as liquid lipid. The lipid nanoparticles were prepared by high pressure homogenization at varying liquid lipid content, in comparison with the γ-oryzanol free systems. The size of the lipid nanoparticles, as measured by the photon correlation spectroscopy, was found to decrease with increased liquid lipid content from 200 to 160 nm. High-resolution proton nuclear magnetic resonance (1H-NMR) measurements of the medium chain triglyceride of the liquid lipid has confirmed successful incorporation of the liquid lipid in the lipid nanoparticles. Differential scanning calorimetric and powder x-ray diffraction measurements provide complementary results to the 1H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of γ-oryzanol inside the lipid nanoparticles, the 1H-NMR revealed that the chemical shifts of the liquid lipid in γ-oryzanol loaded systems were found at rather higher field than those in γ-oryzanol free systems, suggesting incorporation of γ-oryzanol in the liquid lipid. In addition, the phase-separated structure was observed by atomic force microscopy for lipid nanoparticles with 0% liquid lipid, but not for lipid nanoparticles with 5 and 10% liquid lipid. Raman spectroscopic and mapping measurements further revealed preferential incorporation of γ-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models representing the distribution of γ-oryzanol and

  7. Chemical and structural investigation of lipid nanoparticles: drug-lipid interaction and molecular distribution

    International Nuclear Information System (INIS)

    Anantachaisilp, Suranan; Smith, Siwaporn Meejoo; Treetong, Alongkot; Ruktanonchai, Uracha Rungsardthong; Pratontep, Sirapat; Puttipipatkhachorn, Satit

    2010-01-01

    Lipid nanoparticles are a promising alternative to existing carriers in chemical or drug delivery systems. A key challenge is to determine how chemicals are incorporated and distributed inside nanoparticles, which assists in controlling chemical retention and release characteristics. This study reports the chemical and structural investigation of γ-oryzanol loading inside a model lipid nanoparticle drug delivery system composed of cetyl palmitate as solid lipid and Miglyol 812 as liquid lipid. The lipid nanoparticles were prepared by high pressure homogenization at varying liquid lipid content, in comparison with the γ-oryzanol free systems. The size of the lipid nanoparticles, as measured by the photon correlation spectroscopy, was found to decrease with increased liquid lipid content from 200 to 160 nm. High-resolution proton nuclear magnetic resonance ( 1 H-NMR) measurements of the medium chain triglyceride of the liquid lipid has confirmed successful incorporation of the liquid lipid in the lipid nanoparticles. Differential scanning calorimetric and powder x-ray diffraction measurements provide complementary results to the 1 H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of γ-oryzanol inside the lipid nanoparticles, the 1 H-NMR revealed that the chemical shifts of the liquid lipid in γ-oryzanol loaded systems were found at rather higher field than those in γ-oryzanol free systems, suggesting incorporation of γ-oryzanol in the liquid lipid. In addition, the phase-separated structure was observed by atomic force microscopy for lipid nanoparticles with 0% liquid lipid, but not for lipid nanoparticles with 5 and 10% liquid lipid. Raman spectroscopic and mapping measurements further revealed preferential incorporation of γ-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models representing the distribution of γ-oryzanol and

  8. Chemical synthesis of Cu2Se nanoparticles at room temperature

    International Nuclear Information System (INIS)

    Rong, Fengxia; Bai, Yan; Chen, Tianfeng; Zheng, Wenjie

    2012-01-01

    Graphical abstract: The Cu 2 Se nanoparticles were synthesized by a simple and rapid method at room temperature. The TEM and SEM images show that the Cu 2 Se nanoparticles were spherical. Highlights: ► Cu 2 Se nanoparticles were synthesized by the reaction of nanoSe 0 sol with Cu + ions. ► The Cu 2 Se nanoparticles were spherical with cubic structure and well crystallized. ► Optical and electrochemical properties of Cu 2 Se nanoparticles were observed. ► The formation mechanism of Cu 2 Se nanoparticles was proposed. -- Abstract: A simple and rapid method has been developed to synthesize cuprous selenide (Cu 2 Se) nanoparticles by the reaction of selenium nanoparticles sol with copper sulfate solution containing ascorbic acid at room temperature. Cu 2 Se nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and energy dispersive X-ray analysis (EDX). The results indicated that Cu 2 Se nanoparticles were cubic crystal structure and spherical with the diameter about 75 nm. The ultraviolet–visible absorption spectrum (UV–vis) and cyclic voltammetry of Cu 2 Se nanoparticles were also investigated. The optical band gap energy of Cu 2 Se nanoparticles was 1.94 eV. On the basis of a series of experiments and characterizations, the formation mechanism of Cu 2 Se nanoparticles was discussed.

  9. Initial evaluation of dry storage issues for spent nuclear fuels in wet storage at the Idaho Chemical Processing Plant

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, R J; Johnson, Jr, A B; Lund, A L; Gilbert, E R [and others

    1996-07-01

    The Pacific Northwest Laboratory has evaluated the basis for moving selected spent nuclear fuels in the CPP-603 and CPP-666 storage pools at the Idaho Chemical Processing Plant from wet to dry interim storage. This work is being conducted for the Lockheed Idaho Technologies Company as part of the effort to determine appropriate conditioning and dry storage requirements for these fuels. These spent fuels are from 22 test reactors and include elements clad with aluminum or stainless steel and a wide variety of fuel materials: UAl{sub x}, UAl{sub x}-Al and U{sub 3}O{sub 8}-Al cermets, U-5% fissium, UMo, UZrH{sub x}, UErZrH, UO{sub 2}-stainless steel cermet, and U{sub 3}O{sub 8}-stainless steel cermet. The study also included declad uranium-zirconium hydride spent fuel stored in the CPP-603 storage pools. The current condition and potential failure mechanisms for these spent fuels were evaluated to determine the impact on conditioning and dry storage requirements. Initial recommendations for conditioning and dry storage requirements are made based on the potential degradation mechanisms and their impacts on moving the spent fuel from wet to dry storage. Areas needing further evaluation are identified.

  10. Initial evaluation of dry storage issues for spent nuclear fuels in wet storage at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Guenther, R.J.; Johnson, A.B. Jr.; Lund, A.L.; Gilbert, E.R.

    1994-11-01

    The Pacific Northwest Laboratory has evaluated the basis for moving selected spent nuclear fuels in the CPP-603 and CPP-666 storage pools at the Idaho Chemical Processing Plant from wet to dry interim storage. This work is being conducted for the Lockheed Idaho Technologies Company as part of the effort to determine appropriate conditioning and dry storage requirements for these fuels. These spent fuels are from 22 test reactors and include elements clad with aluminum or stainless steel and a wide variety of fuel materials: UAl x , UAl x -Al and U 3 O 8 -Al cermets, U-5% fissium, UMo, UZrH x , UErZrH, UO 2 -stainless steel cermet, and U 3 O 8 -stainless steel cermet. The study also included declad uranium-zirconium hydride spent fuel stored in the CPP-603 storage pools. The current condition and potential failure mechanisms for these spent fuels were evaluated to determine the impact on conditioning and dry storage requirements. Initial recommendations for conditioning and dry storage requirements are made based on the potential degradation mechanisms and their impacts on moving the spent fuel from wet to dry storage. Areas needing further evaluation are identified

  11. Influence of Air Pollution on Chemical Quality of Wet Atmospheric Deposition: a Case Study in Urmia, Iran

    Directory of Open Access Journals (Sweden)

    Yaghoub Hajizadeh

    2017-10-01

    Full Text Available Increased combustion of fossil fuel owing to the energy requirement is a main cause of air pollution throughout the world. Atmospheric precipitation is considered as a major water resource for indoor, municipal, industrial and agricultural uses. This study was aimed to evaluate the effect of air pollution on chemical quality of rain and snow in Urmia, a city in northwest of Iran. Sampling was performed during the wet seasons from October to March at six sampling stations in different locations of the city. Acidity, alkalinity, NO3- , SO42-, Cl- and pH contents of the collected samples were analyzed. All samples showed a pH value of more than 6.8, and lower acidity than alkalinity, therefore, the precipitations were not acidic. Maximum concentrations of SO42- and NO3- in the samples were 5 and 8.8mg/L, respectively. Chloride was varied from 1 to 11.5 mg/L with the highest measures observing in autumn. According to the results, concentrations of the analyzed parameters in wet precipitations in Urmia were within the natural ranges except chloride ions, which was higher than its common level in the atmosphere. This phenomenon may be the result of desert dusts which transfers by wind from the west border to Iran. ‎

  12. Enzymatically and chemically oxidized lignin nanoparticles for biomaterial applications.

    Science.gov (United States)

    Mattinen, Maija-Liisa; Valle-Delgado, Juan José; Leskinen, Timo; Anttila, Tuomas; Riviere, Guillaume; Sipponen, Mika; Paananen, Arja; Lintinen, Kalle; Kostiainen, Mauri; Österberg, Monika

    2018-04-01

    Cross-linked and decolorized lignin nanoparticles (LNPs) were prepared enzymatically and chemically from softwood Kraft lignin. Colloidal lignin particles (CLPs, ca. 200 nm) in a non-malodorous aqueous dispersion could be dried and redispersed in tetrahydrofuran (THF) or in water retaining their stability i.e. spherical shape and size. Two fungal laccases, Trametes hirsuta (ThL) and Melanocarpus albomyces (MaL) were used in the cross-linking reactions. Reactivity of ThL and MaL on Lignoboost™ lignin and LNPs was confirmed by high performance size exclusion chromatography (HPSEC) and oxygen consumption measurements with simultaneous detection of red-brown color due to the formation of quinones. Zeta potential measurements verified oxidation of LNPs via formation of surface-oriented carboxylic acid groups. Dynamic light scattering (DLS) revealed minor changes in the particle size distributions of LNPs after laccase catalyzed radicalization, indicating preferably covalent intraparticular cross-linking over polymerization. Changes in the surface morphology of laccase treated LNPs were imaged by atomic force (AFM) and transmission emission (TEM) microscopy. Furthermore, decolorization of LNPs without degradation was obtained using ultrasonication with H 2 O 2 in alkaline reaction conditions. The research results have high impact for the utilization of Kraft lignin as nanosized colloidal particles in advanced bionanomaterial applications in medicine, foods and cosmetics including different sectors from chemical industry. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  13. chemical and physical comparative study of the effect of wet and dry ...

    African Journals Online (AJOL)

    eobe

    The clay content of the raw clay which was 48 wt% was improved to 73 wt%. The clay content of the ... refractories and wide spectrum of ceramics [4, 5] in several industries. ... physicochemical properties, which can be determined by chemical ...

  14. Synthesis of Monodispersed Spherical Single Crystalline Silver Particles by Wet Chemical Process; Shisshiki kagakuho ni yoru tanbunsankyujo tankesshoginryushi no gose

    Energy Technology Data Exchange (ETDEWEB)

    Ueyama, Ryousuke.; Harada, Masahiro.; Ueyama, Tamotsu.; Harada, Akio. [Daiken Chemistry Industry Corporation, Osaka (Japan); Yamamoto, Takashi. [National Defence Academy, Kanagawa (Japan). Dept. of Electrical Engineering; Shiosaki, Tadashi. [Nara Institute of Science and Technology, Nara (Japan). Graduate School of Materials Science; Kuribayashi, Kiyoshi. [Teikyo University of Science and Technology, Yamanashi (Japan). Dept. of Materials

    1999-01-01

    Ultrafine silver monodispersed particle were prepared by wet chemical process. To decrease the reduction speed, an important factor in generating monodispersed particles is to control the following three factors: synthesis temperature, concentration of aggregation-relaxing agent added, and concentration of silver nitrate solution. Synthesis of monodispersed spherical Ag particles, used as metal powders for electrode, became possible using the nucleus grouwth reaction method. This process also allowed the control of the diameter of the powder particles. The silver particles were distributed in ta narrow particle diameter range with on average of 0.5 {mu}m. Transmission electron microscopy (TEM) revealed that single-crystalline silver particles were prepared by the present method. (author)

  15. Investigation on structural and optical properties of ZnO film prepared by simple wet chemical method

    Science.gov (United States)

    Sholehah, Amalia; Mulyadi, Rendi; Haryono, Didied; Muttakin, Imamul; Rusbana, Tb Bahtiar; Mardiyanto

    2018-04-01

    ZnO thin layer has a broad potential application in electronic and optoelectronic devices. In this study, vertically align ZnO layers were deposited on ITO glass using wet chemistry method. The seed layers were prepared using electrodeposition technique at 3°C. The growing process was carried out using chemical bath deposition at 90°C. To improve the structural properties, two different hydrothermal treatment variations were applied separately. From the experiment, it is shown that the hydrothermal process using N2 gas has given the best result, with average diameter, crystallite size, and band-gap energy of 68.83 nm; 56.37 nm; and 3.16 eV, respectively.

  16. Wet-Chemical Preparation of Silicon Tunnel Oxides for Transparent Passivated Contacts in Crystalline Silicon Solar Cells.

    Science.gov (United States)

    Köhler, Malte; Pomaska, Manuel; Lentz, Florian; Finger, Friedhelm; Rau, Uwe; Ding, Kaining

    2018-05-02

    Transparent passivated contacts (TPCs) using a wide band gap microcrystalline silicon carbide (μc-SiC:H(n)), silicon tunnel oxide (SiO 2 ) stack are an alternative to amorphous silicon-based contacts for the front side of silicon heterojunction solar cells. In a systematic study of the μc-SiC:H(n)/SiO 2 /c-Si contact, we investigated selected wet-chemical oxidation methods for the formation of ultrathin SiO 2 , in order to passivate the silicon surface while ensuring a low contact resistivity. By tuning the SiO 2 properties, implied open-circuit voltages of 714 mV and contact resistivities of 32 mΩ cm 2 were achieved using μc-SiC:H(n)/SiO 2 /c-Si as transparent passivated contacts.

  17. A simple cost-effective and eco-friendly wet chemical process for the fabrication of superhydrophobic cotton fabrics

    Energy Technology Data Exchange (ETDEWEB)

    Richard, Edna; Lakshmi, R.V.; Aruna, S.T., E-mail: aruna_reddy@nal.res.in; Basu, Bharathibai J.

    2013-07-15

    Superhydrophobic surfaces were created on hydrophilic cotton fabrics by a simple wet chemical process. The fabric was immersed in a colloidal suspension of zinc hydroxide followed by subsequent hydrophobization with stearic acid. The wettability of the modified cotton fabric sample was studied by water contact angle (WCA) and water shedding angle (WSA) measurements. The modified cotton fabrics exhibited superhydrophobicity with a WCA of 151° for 8 μL water droplet and a WSA of 5–10° for 40 μL water droplet. The superhydrophobic cotton sample was also characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The method is simple, eco-friendly and cost-effective and can be applied to large area of cotton fabric materials. It was shown that superhydrophobicity of the fabric was due to the combined effect of surface roughness imparted by zinc hydroxide and the low surface energy of stearic acid.

  18. A simple cost-effective and eco-friendly wet chemical process for the fabrication of superhydrophobic cotton fabrics

    International Nuclear Information System (INIS)

    Richard, Edna; Lakshmi, R.V.; Aruna, S.T.; Basu, Bharathibai J.

    2013-01-01

    Superhydrophobic surfaces were created on hydrophilic cotton fabrics by a simple wet chemical process. The fabric was immersed in a colloidal suspension of zinc hydroxide followed by subsequent hydrophobization with stearic acid. The wettability of the modified cotton fabric sample was studied by water contact angle (WCA) and water shedding angle (WSA) measurements. The modified cotton fabrics exhibited superhydrophobicity with a WCA of 151° for 8 μL water droplet and a WSA of 5–10° for 40 μL water droplet. The superhydrophobic cotton sample was also characterized by field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). The method is simple, eco-friendly and cost-effective and can be applied to large area of cotton fabric materials. It was shown that superhydrophobicity of the fabric was due to the combined effect of surface roughness imparted by zinc hydroxide and the low surface energy of stearic acid.

  19. Formation of hydrogen-related traps in electron-irradiated n-type silicon by wet chemical etching

    International Nuclear Information System (INIS)

    Tokuda, Yutaka; Shimada, Hitoshi

    1998-01-01

    Interaction of hydrogen atoms and vacancy-related defects in 10 MeV electron-irradiated n-type silicon has been studied by deep-level transient spectroscopy. Hydrogen has been incorporated into electron-irradiated n-type silicon by wet chemical etching. The reduction of the concentration of the vacancy-oxygen pair and divacancy occurs by the incorporation of hydrogen, while the formation of the NH1 electron trap (E c - 0.31 eV) is observed. Further decrease of the concentration of the vacancy-oxygen pair and further increase of the concentration of the NH1 trap are observed upon subsequent below-band-gap light illumination. It is suggested that the trap NH1 is tentatively ascribed to the vacancy-oxygen pair which is partly saturated with hydrogen

  20. Green synthesis of nanocrystalline α-Al2O3 powders by both wet-chemical and mechanochemical methods

    Science.gov (United States)

    Gao, Huiying; Li, Zhiyong; Zhao, Peng

    2018-03-01

    Nanosized α-Al2O3 powders were prepared with AlCl3ṡ6H2O and NH4HCO3 as raw materials by both wet-chemical and mechanochemical methods, through the synthesis of the ammonium aluminum carbonate hydroxide (AACH) precursor followed by calcination. The environmentally benign starch was used as an effective dispersant during the preparation of nanocrystalline α-Al2O3 powders. X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to characterize the precursor AACH and products. The results show that nanosized spherical α-Al2O3 powders without hard agglomeration and with particle size in the range of 20-40 nm can be obtained by the two methods. Comparing the two “green” processes, the mechanochemical method has better prospects for commercial production.

  1. Enhanced local piezoelectric response in the erbium-doped ZnO nanostructures prepared by wet chemical synthesis

    Directory of Open Access Journals (Sweden)

    Reza Zamiri

    2017-03-01

    Full Text Available Pure and erbium (Er doped ZnO nanostructures were prepared by simple and cost effective wet chemical precipitation method. The successful doping with phase purity of prepared ZnO nanostructure was confirmed by X-ray diffraction (XRD and their Rietveld analysis. The change in structural morphology of nanoscale features of prepared ZnO nanopowders on Er doping was observed from their scanning electron microscopy (SEM images. The presence of Er in prepared ZnO nanopowder was further confirmed from corresponding energy dispersive X-ray spectroscopy (EDX spectra of scanned SEM images. Piezoelectric properties of before (green samples and after sintering of consolidated compact of synthesized nanopowders were successfully measured. The out-of-plane (effective longitudinal and in-plane (effective shear coefficients of the samples were estimated from the local piezoresponse.

  2. Chemical modification of cobalt ferrite nanoparticles with possible application as asphaltene flocculant agent

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, G.E.; Clarindo, J.E.S.; Santo, K.S.E., E-mail: geiza.oliveira@ufes.br [Universidade Federal do Espirito Santo (CCE/DQUI/UFES), Vitoria, ES (Brazil). Centro de Ciencias Exatas. Dept. de Quimica; Souza Junior, F.G. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Macromoleculas

    2013-11-01

    Asphaltenes can cause enormous losses in the oil industry, because they are soluble only in aromatic solvents. Therefore, they must be removed from the petroleum before it is refined, using flocculant agents. Aiming to find new materials that can work as flocculant agents to asphaltenes, cobalt ferrite nanoparticles were chemically modified through acid-base reactions using dodecylbenzene sulfonic acid (DBSA) to increase their lipophilicity. Nanoparticle synthesis was performed using the co-precipitation method followed by annealing of these nanoparticles, aiming to change the structural phase. Modified and unmodified nanoparticles were tested by FTIR-ATR, XRD and TGA/DTA. In addition, precipitation onset of the asphaltenes was performed using modified and unmodified nanoparticles. These tests showed that modified nanoparticles have a potential application as flocculant agents used to remove asphaltenes before oil refining, since the presence of nanoparticles promotes the asphaltene precipitation onset with the addition of a small amount of non-solvent (author)

  3. Chemical modification of cobalt ferrite nanoparticles with possible application as asphaltene flocculant agent

    International Nuclear Information System (INIS)

    Oliveira, G.E.; Clarindo, J.E.S.; Santo, K.S.E.; Souza Junior, F.G.

    2013-01-01

    Asphaltenes can cause enormous losses in the oil industry, because they are soluble only in aromatic solvents. Therefore, they must be removed from the petroleum before it is refined, using flocculant agents. Aiming to find new materials that can work as flocculant agents to asphaltenes, cobalt ferrite nanoparticles were chemically modified through acid-base reactions using dodecylbenzene sulfonic acid (DBSA) to increase their lipophilicity. Nanoparticle synthesis was performed using the co-precipitation method followed by annealing of these nanoparticles, aiming to change the structural phase. Modified and unmodified nanoparticles were tested by FTIR-ATR, XRD and TGA/DTA. In addition, precipitation onset of the asphaltenes was performed using modified and unmodified nanoparticles. These tests showed that modified nanoparticles have a potential application as flocculant agents used to remove asphaltenes before oil refining, since the presence of nanoparticles promotes the asphaltene precipitation onset with the addition of a small amount of non-solvent (author)

  4. L1{sub 0}-FePt films fabricated by wet-chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Xiaoliang; Xiao, Wen; Bao, Nina; Li, Weimin; Chichvarina, Olga, E-mail: A0077107@nus.edu.sg; Ding, Jun, E-mail: msedingj@nus.edu.sg

    2015-08-31

    In this work, we have developed a method to fabricate FePt films by a combination of chemical deposition and post-annealing. Pt-doped Fe films were deposited on Pt(100 nm)/Ti(50 nm)/SiO{sub 2}/Si substrate using thermal deposition and the as-deposited films were subsequently annealed from 300 °C to 800 °C under 5% H{sub 2}/95% N{sub 2}. FePt films were achieved through diffusion and rearrangement of Fe and Pt atoms in post-annealing process. From X-ray diffraction results, the face-centered cubic (fcc) FePt phase appeared at 300 °C and the transformation from fcc to L1{sub 0} phase started at 400 °C. The L1{sub 0}-FePt film possessed an out-of-plane anisotropy and a coercivity of 729 kA/m after annealing at 600 °C. A further increase in annealing temperature led to lower value of coercivity, probably because of grain growth. In addition, the thickness of Pt-doped Fe films could be controlled from 150 nm to 700 nm by adjusting the amount of surfactant used. Our superconducting quantum interference device analysis showed that Pt dopant could significantly improve the chemical stability of Fe films in air. - Highlights: • We fabricated FePt film by a combination of chemical deposition and post-annealing. • L1{sub 0} FePt film was formed by Fe/Pt diffusion in annealing of Pt-doped Fe film. • L1{sub 0}-phase FePt with high coercivity and small out-of-plane anisotropy • Relatively small amount of Pt dopant can enhance chemical stability greatly. • We studied structure and magnetic property of as-deposited and annealed FePt film.

  5. Chemical synthesis, characterization and evaluation of antimicrobial properties of Cu and its oxide nanoparticles

    CSIR Research Space (South Africa)

    Motlatle, Abesach M

    2016-10-01

    Full Text Available of Nanoparticle Research, vol. 18: DOI: 10.1007/s11051-016-3614-8 Chemical synthesis, characterization and evaluation of antimicrobial properties of Cu and its oxide nanoparticles Motlatle AM Kesevan Pillai S Scriba MR Ray SS ABSTRACT: Cu...

  6. A comparative study of hydroxyapatite nanoparticles synthesized by different routes

    OpenAIRE

    Paz, Adrian; Guadarrama, Dainelys; López, Mónica; E. González, Jesús; Brizuela, Nayrim; Aragón, Javier

    2012-01-01

    In this study, bioactive hydroxyapatite nanoparticles were prepared by two different methods: wet chemical precipitation and biomimetic precipitation. The aim was to evaluate the morphology, particle-size, crystallinity and phases of the powders obtained by traditional wet chemical precipitation and the novel biomimetic precipitation using a supersaturated calcium solution. The nanoparticles were investigated by transmission electron microscopy, Fourier transform infrared spectroscopy and X-r...

  7. Assessing preferential flow by simultaneously injecting nanoparticle and chemical tracers

    KAUST Repository

    Subramanian, S. K.; Li, Yan; Cathles, L. M.

    2013-01-01

    The exact manner in which preferential (e.g., much faster than average) flow occurs in the subsurface through small fractures or permeable connected pathways of other kinds is important to many processes but is difficult to determine, because most chemical tracers diffuse quickly enough from small flow channels that they appear to move more uniformly through the rock than they actually do. We show how preferential flow can be assessed by injecting 2 to 5 nm carbon particles (C-Dots) and an inert KBr chemical tracer at different flow rates into a permeable core channel that is surrounded by a less permeable matrix in laboratory apparatus of three different designs. When the KBr tracer has a long enough transit through the system to diffuse into the matrix, but the C-Dot tracer does not, the C-Dot tracer arrives first and the KBr tracer later, and the separation measures the degree of preferential flow. Tracer sequestration in the matrix can be estimated with a Peclet number, and this is useful for experiment design. A model is used to determine the best fitting core and matrix dispersion parameters and refine estimates of the core and matrix porosities. Almost the same parameter values explain all experiments. The methods demonstrated in the laboratory can be applied to field tests. If nanoparticles can be designed that do not stick while flowing through the subsurface, the methods presented here could be used to determine the degree of fracture control in natural environments, and this capability would have very wide ranging value and applicability.

  8. Dependence of Nanoparticle Toxicity on Their Physical and Chemical Properties

    Science.gov (United States)

    Sukhanova, Alyona; Bozrova, Svetlana; Sokolov, Pavel; Berestovoy, Mikhail; Karaulov, Alexander; Nabiev, Igor

    2018-02-01

    Studies on the methods of nanoparticle (NP) synthesis, analysis of their characteristics, and exploration of new fields of their applications are at the forefront of modern nanotechnology. The possibility of engineering water-soluble NPs has paved the way to their use in various basic and applied biomedical researches. At present, NPs are used in diagnosis for imaging of numerous molecular markers of genetic and autoimmune diseases, malignant tumors, and many other disorders. NPs are also used for targeted delivery of drugs to tissues and organs, with controllable parameters of drug release and accumulation. In addition, there are examples of the use of NPs as active components, e.g., photosensitizers in photodynamic therapy and in hyperthermic tumor destruction through NP incorporation and heating. However, a high toxicity of NPs for living organisms is a strong limiting factor that hinders their use in vivo. Current studies on toxic effects of NPs aimed at identifying the targets and mechanisms of their harmful effects are carried out in cell culture models; studies on the patterns of NP transport, accumulation, degradation, and elimination, in animal models. This review systematizes and summarizes available data on how the mechanisms of NP toxicity for living systems are related to their physical and chemical properties.

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

    Directory of Open Access Journals (Sweden)

    J. Kleffmann

    2008-11-01

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

  10. Controlled low-temperature fabrication of ZnO nanopillars with a wet-chemical approach

    Energy Technology Data Exchange (ETDEWEB)

    Postels, B [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Wehmann, H-H [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Bakin, A [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Kreye, M [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Fuhrmann, D [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, D-38106 Braunschweig (Germany); Blaesing, J [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Universitaetsplatz 1, 39016 Magdeburg (Germany); Hangleiter, A [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, D-38106 Braunschweig (Germany); Krost, A [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Universitaetsplatz 1, 39016 Magdeburg (Germany); Waag, A [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany)

    2007-05-16

    Aqueous chemical growth (ACG) is an efficient way to generate wafer-scale and densely packed arrays of ZnO nanopillars on various substrate materials. ACG is a low-temperature growth approach that is only weakly influenced by the substrate and even allows growth on flexible polymer substrates or on conducting materials. The advanced fabrication of wafer-scale and highly vertically aligned arrays of ZnO nanopillars on various substrate materials is demonstrated. Moreover, it is possible to control the morphology in diameter and length by changing the growth conditions. Photoluminescence characterization clearly shows a comparatively strong band-edge luminescence, even at room temperature, that is accompanied by a rather weak visible luminescence in the yellow/orange spectral range.

  11. Measurement of discrete energy-level spectra in individual chemically synthesized gold nanoparticles

    DEFF Research Database (Denmark)

    Kuemmeth, Ferdinand; Bolotin, Kirill I; Shi, Su-Fei

    2008-01-01

    We form single-electron transistors from individual chemically synthesized gold nanoparticles, 5-15 nm in diameter, with monolayers of organic molecules serving as tunnel barriers. These devices allow us to measure the discrete electronic energy levels of individual gold nanoparticles that are......, by virtue of chemical synthesis, well-defined in their composition, size and shape. We show that the nanoparticles are nonmagnetic and have spectra in good accord with random-matrix-theory predictions taking into account strong spin-orbit coupling....

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  13. Efficient 2-Nitrophenol Chemical Sensor Development Based on Ce2O3 Nanoparticles Decorated CNT Nanocomposites for Environmental Safety.

    Directory of Open Access Journals (Sweden)

    Mohammad M Hussain

    Full Text Available Ce2O3 nanoparticle decorated CNT nanocomposites (Ce2O3.CNT NCs were prepared by a wet-chemical method in basic medium. The Ce2O3.CNT NCs were examined using FTIR, UV/Vis, Field-Emission Scanning Electron Microscopy (FESEM, X-ray electron dispersive spectroscopy (XEDS, X-ray photoelectron spectroscopy (XPS, and powder X-ray diffraction (XRD. A selective 2-nitrophenol (2-NP sensor was developed by fabricating a thin-layer of NCs onto a flat glassy carbon electrode (GCE, surface area = 0.0316 cm2. Higher sensitivity including linear dynamic range (LDR, long-term stability, and enhanced electrochemical performances towards 2-NP were achieved by a reliable current-voltage (I-V method. The calibration curve was found linear (R2 = 0.9030 over a wide range of 2-NP concentration (100 pM ~ 100.0 mM. Limit of detection (LOD and sensor sensitivity were calculated based on noise to signal ratio (~3N/S as 60 ± 0.02 pM and 1.6×10-3 μAμM-1cm-2 respectively. The Ce2O3.CNT NCs synthesized by a wet-chemical process is an excellent way of establishing nanomaterial decorated carbon materials for chemical sensor development in favor of detecting hazardous compounds in health-care and environmental fields at broad-scales. Finally, the efficiency of the proposed chemical sensors can be applied and utilized in effectively for the selective detection of toxic 2-NP component in environmental real samples with acceptable and reasonable results.

  14. Extended phase homogeneity and electrical properties of barium calcium titanate prepared by the wet chemical methods

    International Nuclear Information System (INIS)

    Jayanthi, S.; Kutty, T.R.N.

    2004-01-01

    Ca-substituted BaTiO 3 with extended homogeneity range upto ∼50 mol% CaTiO 3 have been prepared by three different chemical routes namely carbonate-oxalate (COBCT), gel-carbonate (GCBCT), and gel-to-crystallite conversion (GHBCT) followed by heat treatment above 1150 deg. C. X-ray powder diffraction (XRD) data show continuous decrease in the tetragonal unit cell parameters as well as c 0 /a 0 ratio with CaTiO 3 content, which are in accordance with the substitution of smaller sized Ca 2+ ions at the barium sites. The microstructure as well as the dielectric properties are greatly influenced by the cationic ratio, α=(Ba+Ca)/Ti. The grain size decreases with CaTiO 3 content for the stoichiometric samples (α=1), whereas ultrafine microstructure is observed in the case of off-stoichiometric samples (α>1) for the whole compositional range of CaTiO 3 concentrations. Sharper ε r -T characteristics at lower calcium content and broader ε r -T with decreased ε max , in the higher calcium range are observed in the case of α=1. Whereas nanometer grained ceramics exhibiting diffuse ε r -T characteristics are obtained in the case of α>1. The positive temperature coefficient of resistivity (PTCR) is realized for barium calcium titanate ceramics having 0.3 at.% Sb as the donor dopant for higher CaTiO 3 (typically 30 mol%) containing samples (α=1), indicating that Ca 2+ ions do not behave as acceptors if they were to substitute at the Ti 4+ sites. Whereas the off-stoichiometric (α>1) ceramics retained high resistivity, indicative of the Ti-site occupancy for Ca 2+ in fine grain ceramics

  15. Gold and gold-copper nanoparticles in 2-propanol: A radiation chemical study

    International Nuclear Information System (INIS)

    Dey, G.R.

    2011-01-01

    The studies on the reduction of Au 3+ to gold nanoparticles in presence and absence of Cu 2+ under deoxygenated conditions in 2-propanol by radiolytic method have been carried out. On γ-radiolysis, preliminary yellow colored solution of Au 3+ changed to purple color owing to gold nanoparticles formation, which exhibits an absorption peak at around 540 nm. In the presence of Cu 2+ , absorption of gold-copper nanoparticles, which was also produced during γ-radiolysis, was red shifted in contrast to the system containing no Cu 2+ . Under DLS studies the sizes of gold nanoparticles in the absence and the presence of Cu 2+ were found to be larger (>400 nm). However, in presence of polyethylene glycol, a stabilizer the nanoparticle sizes became smaller, sizes measured for gold and gold-copper nanoparticles are 40 and 140 nm, respectively. Moreover, the change in UV-vis spectra in the Cu 2+ and Au 3+ mixed system highlights the formation of gold-copper nanoparticles in core-shell type arrangement. - Highlights: → Present radiation chemical study highlights high reactivity of Au ·2+ with Cu 2+ . → Absorption of gold-copper nanoparticles is blue shifted as compared to copper nanoparticles. → Change in UV-vis spectra with dose emphasizes core-shell type arrangement of Au-Cu nanoparticles.

  16. Surface passivation by Al2O3 and a-SiNx: H films deposited on wet-chemically conditioned Si surfaces

    NARCIS (Netherlands)

    Bordihn, S.; Mertens, V.; Engelhart, P.; Kersten, K.; Mandoc, M.M.; Müller, J.W.; Kessels, W.M.M.

    2012-01-01

    The surface passivation of p- and n-type silicon by different chemically grown SiO2 films (prepared by HNO3, H2SO4/H2O2 and HCl/H2O2 treatments) was investigated after PECVD of a-SiNx:H and ALD of Al2O3 capping films. The wet chemically grown SiO2 films were compared to thermally grown SiO2 and the

  17. Chemical Vapor Deposition of Photocatalyst Nanoparticles on PVDF Membranes for Advanced Oxidation Processes

    Directory of Open Access Journals (Sweden)

    Giovanni De Filpo

    2018-06-01

    Full Text Available The chemical binding of photocatalytic materials, such as TiO2 and ZnO nanoparticles, onto porous polymer membranes requires a series of chemical reactions and long purification processes, which often result in small amounts of trapped nanoparticles with reduced photocatalytic activity. In this work, a chemical vapor deposition technique was investigated in order to allow the nucleation and growth of ZnO and TiO2 nanoparticles onto polyvinylidene difluoride (PVDF porous membranes for application in advanced oxidation processes. The thickness of obtained surface coatings by sputtered nanoparticles was found to depend on process conditions. The photocatalytic efficiency of sputtered membranes was tested against both a model drug and a model organic pollutant in a small continuous flow reactor.

  18. Chemical synthesis and characterization of hollow dopamine coated, pentagonal and flower shaped magnetic iron oxide nanoparticles

    Science.gov (United States)

    Riasat, Rabia; Kaynat, Sumbal

    2018-04-01

    Iron oxide nanoparticles have gained attention recently in the field of nanoscience and technology due to their unique physicochemical properties. We hereby chemically synthesized novel pentagonal flower shaped iron oxide nanoparticles by thermal decomposition of iron penta-carbonyl in a two way annealing process. Controlled oxidation by acid etching was performed for these nanoparticles. At first 13 nm core shell nanoparticles of iron oxide (Fe/Fe3O4) were synthesized at 120°C annealing temperature that act as template material. The core shell nanoparticles then converted into porous hollow core shell nanoparticles (PH Fe/ Fe3O4) in a two way annealing process of heating, first at 100°C then at 250°C and heating rate of 5°C was kept constant throughout the reaction time. X-Ray diffraction (XRD) was done for the phase confirmation of as synthesized nanoparticles. Transmission electron microscopy (TEM) and higher resolution transmission electron microscopy (HRTEM) clearly shows the flower like nanoparticles that are approx. 16 nm-18 nm in size having the 4-5 nm core of Fe and 1-2 nm of the pores in the shell while the cavity between the shell and core is about 2 nm and the shell is 4-5 nm in diameter according to the TEM micrographs. The as prepared nanoparticles were then surface functionalized by dopamine polymer to make them water dispersible. Fourier transform Infrared spectroscopy confirmed the dopamine coating on the nanoparticles and the magnetic saturation of 38 emu/g of nanoparticles was analyzed by vibrating sample magnetometer (VSM). Magnetic saturation persists in the dopamine coated nanoparticles. These nanoparticles were surface functionalized with dopamine and show dispersity in the aqueous media and can further be exploited in many nano-biotechnological applications including target specific therapeutic applications for several diseases.

  19. Structural, morphological, wettability and thermal resistance properties of hydro-oleophobic thin films prepared by a wet chemical process

    International Nuclear Information System (INIS)

    Phani, A.R.

    2006-01-01

    The structural properties of fluorine containing polymer compounds make them highly attractive materials for hydro-oleophobic applications. However, most of these exhibit low surface energy and poor adhesion on the substrates. In the present investigation, crack free, smooth and uniform thin films of poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole] -co-tetrafluoroethylene (TFD-co-TFE) with good adhesion have been deposited by wet chemical spin-coating technique on polished AISI 440C steel substrates. The as-deposited films (xerogel films) have been subjected to annealing for 1 h at different temperatures ranging from 100 to 500 deg. C in an argon atmosphere. The size growth of the nano-hemispheres increased from 8 nm for xerogel film to 28 nm for film annealed at 400 deg. C. It was found that as the annealing temperature increased from 100 to 400 deg. C, nano-hemisphere-like structures were formed, which in turn have shown increase in the water contact angle from 122 deg. to 147 deg. and oil (peanut) contact angle from 85 deg. to 96 deg. No change in the water contact angle (122 deg.) has been observed when the films deposited at room temperature were heated in air from 30 to 80 deg. C as well as exposed to steam for 8 days for 8 h/day indicating thermal stability of the film

  20. "Chemical transformers" from nanoparticle ensembles operated with logic.

    Science.gov (United States)

    Motornov, Mikhail; Zhou, Jian; Pita, Marcos; Gopishetty, Venkateshwarlu; Tokarev, Ihor; Katz, Evgeny; Minko, Sergiy

    2008-09-01

    The pH-responsive nanoparticles were coupled with information-processing enzyme-based systems to yield "smart" signal-responsive hybrid systems with built-in Boolean logic. The enzyme systems performed AND/OR logic operations, transducing biochemical input signals into reversible structural changes (signal-directed self-assembly) of the nanoparticle assemblies, thus resulting in the processing and amplification of the biochemical signals. The hybrid system mimics biological systems in effective processing of complex biochemical information, resulting in reversible changes of the self-assembled structures of the nanoparticles. The bioinspired approach to the nanostructured morphing materials could be used in future self-assembled molecular robotic systems.

  1. Isolation and chemical analysis of nanoparticles from English ivy (Hedera helix L.)

    Science.gov (United States)

    Lenaghan, Scott C.; Burris, Jason N.; Chourey, Karuna; Huang, Yujian; Xia, Lijin; Lady, Belinda; Sharma, Ritin; Pan, Chongle; LeJeune, Zorabel; Foister, Shane; Hettich, Robert L.; Stewart, C. Neal; Zhang, Mingjun

    2013-01-01

    Bio-inspiration for novel adhesive development has drawn increasing interest in recent years with the discovery of the nanoscale morphology of the gecko footpad and mussel adhesive proteins. Similar to these animal systems, it was discovered that English ivy (Hedera helix L.) secretes a high strength adhesive containing uniform nanoparticles. Recent studies have demonstrated that the ivy nanoparticles not only contribute to the high strength of this adhesive, but also have ultraviolet (UV) protective abilities, making them ideal for sunscreen and cosmetic fillers, and may be used as nanocarriers for drug delivery. To make these applications a reality, the chemical nature of the ivy nanoparticles must be elucidated. In the current work, a method was developed to harvest bulk ivy nanoparticles from an adventitious root culture system, and the chemical composition of the nanoparticles was analysed. UV/visible spectroscopy, inductively coupled plasma mass spectrometry, Fourier transform infrared spectroscopy and electrophoresis were used in this study to identify the chemical nature of the ivy nanoparticles. Based on this analysis, we conclude that the ivy nanoparticles are proteinaceous. PMID:23883948

  2. Rich Ground State Chemical Ordering in Nanoparticles: Exact Solution of a Model for Ag-Au Clusters

    DEFF Research Database (Denmark)

    Larsen, Peter Mahler; Jacobsen, Karsten Wedel; Schiøtz, Jakob

    2018-01-01

    We show that nanoparticles can have very rich ground state chemical order. This is illustrated by determining the chemical ordering of Ag-Au 309-atom Mackay icosahedral nanoparticles. The energy of the nanoparticles is described using a cluster expansion model, and a Mixed Integer Programming (MIP......) approach is used to find the exact ground state configurations for all stoichiometries. The chemical ordering varies widely between the different stoichiometries, and display a rich zoo of structures with non-trivial ordering....

  3. Leaching and antimicrobial properties of silver nanoparticles loaded onto natural zeolite clinoptilolite by ion exchange and wet impregnation

    CSIR Research Space (South Africa)

    Missengue, RNM

    2015-11-01

    Full Text Available This study aimed to compare the leaching and antimicrobial properties of silver that was loaded onto the natural zeolite clinoptilolite by ion exchange and wet impregnation. Silver ions were reduced using sodium borohydride (NaBH(sub4...

  4. Size-controlled Synthesis and Characterization of Fe3O4 Nanoparticles by Chemical Coprecipitation Method

    International Nuclear Information System (INIS)

    Chia Chin Hua; Sarani Zakaria; Farahiyan, R.; Liew Tze Khong; Mustaffa Abdullah; Sahrim Ahmad; Nguyen, K.L.

    2008-01-01

    Magnetite (Fe 3 O 4 ) nanoparticles have been synthesized using the chemical coprecipitation method. The Fe 3 O 4 nanoparticles were likely formed via dissolution-recrystallization process. During the precipitation process, ferrihydrite and Fe(OH) 2 particles formed aggregates and followed by the formation of spherical Fe 3 O 4 particles. The synthesized Fe 3 O 4 nanoparticles exhibited superparamagnetic behavior and in single crystal form. The synthesis temperature and the degree of agitation during the precipitation were found to be decisive in controlling the crystallite and particle size of the produced Fe 3 O 4 nanoparticles. Lower temperature and higher degree of agitation were the favorable conditions for producing smaller particle. The magnetic properties (saturation magnetization and coercivity) of the Fe 3 O 4 nanoparticles increased with the particle size. (author)

  5. Fabrication and Characterization of Zinc Sulfide Nanoparticles and Nanocomposites Prepared via a Simple Chemical Precipitation Method

    Directory of Open Access Journals (Sweden)

    Kambiz Hedayati

    2016-07-01

    Full Text Available In this research zinc sulfide (ZnS nanoparticles and nanocomposites powders were prepared by chemical precipitation method using zinc acetate and various sulfur sources. The ZnS nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible and fourier transform infra-red. The structure of nanoparticles was studied using X-ray diffraction pattern. The crystallite size of ZnS nanoparticles was calculated by Debye–Scherrer formula. Morphology of nano-crystals was observed and investigated using the scanning electron microscopy. The grain size of zinc sulfide nanoparticles were in suitable agreement with the crystalline size calculated by X-ray diffraction results. The optical properties of particles were studied with ultraviolet-visible absorption spectrum.

  6. Models of nanoparticles movement, collision, and friction in chemical mechanical polishing (CMP)

    Energy Technology Data Exchange (ETDEWEB)

    Ilie, Filip, E-mail: filip@meca.omtr.pub.ro [Polytechnic University of Bucharest, Department of Machine Elements and Tribology (Romania)

    2012-03-15

    Nanoparticles have been widely used in polishing slurry such as chemical mechanical polishing (CMP) process. The movement of nanoparticles in polishing slurry and the interaction between nanoparticles and solid surface are very important to obtain an atomic smooth surface in CMP process. Polishing slurry contains abrasive nanoparticles (with the size range of about 10-100 nm) and chemical reagents. Abrasive nanoparticles and hydrodynamic pressure are considered to cause the polishing effect. Nanoparticles behavior in the slurry with power-law viscosity shows great effect on the wafer surface in polishing process. CMP is now a standard process of integrated circuit manufacturing at nanoscale. Various models can dynamically predict the evolution of surface topography for any time point during CMP. To research, using a combination of individual nanoscale friction measurements for CMP of SiO{sub 2}, in an analytical model, to sum these effects, and the results scale CMP experiments, can guide the research and validate the model. CMP endpoint measurements, such as those from motor current traces, enable verification of model predictions, relating to friction and wear in CMP and surface topography evolution for different types of CMP processes and patterned chips. In this article, we explore models of the microscopic frictional force based on the surface topography and present both experimental and theoretical studies on the movement of nanoparticles in polishing slurry and collision between nanoparticles, as well as between the particles and solid surfaces in time of process CMP. Experimental results have proved that the nanoparticle size and slurry properties have great effects on the polishing results. The effects of the nanoparticle size and the slurry film thickness are also discussed.

  7. Green Synthesis of Formulated Zinc Oxide Nanoparticles for Chemical Protection of Skin Care and Related Applications

    Science.gov (United States)

    Koppolu, Ramya

    Nanomaterials have diversified applications based on the unique properties. These nanoparticles and functionalized nanocomposites have been studied in the health care filed. Nanoparticles are mostly used in sunscreens which are a part of human life. These sunscreens consist of titanium dioxide and zinc oxide nanoparticles. Due to the higher band crevices, they help the skin to protect from ultraviolet rays, for instance, ultraviolet B and ultraviolet A. A series of nanostructured zinc oxide nanoparticles were prepared by cost-effective chemical and bioinspired methods and variables were optimized. Highly stable and spherical zinc oxide nanoparticles were formulated by aloe vera ( Aloe barbadensis) plant extract and avocado (Persea americana Mill) fruit extract. The state-of-the-art instrumentation was used to characterize the morphology, elemental composition, and particle size distribution. X-ray diffraction data indicated highly crystalline and ultrafine nanoparticles were obtained from the colloidal methods. The X-ray photoelectron spectroscopy results showed the chemical state of zinc, carbon, and oxygen atoms were well-indexed and are used as fingerprint identification of the elements. Transmission electron microscopy images show the shape of particles were cubic and fiber shape contingent upon the protecting operators and heat treatment conditions. The toxicity studies of zinc oxide nanoparticles were found to cause an increase in nitric oxide, which is protecting against further oxidative stress and appears to be nontoxic.

  8. Comparison of the chemical properties of wheat straw and beech fibers following alkaline wet oxidation and laccase treatments

    DEFF Research Database (Denmark)

    Schmidt, A. S.; Mallon, S.; Thomsen, Anne Belinda

    2002-01-01

    Wheat straw (Triticum aestivum) and beech (Fagus sylvatica), were used to evaluate the effects of two pre-treatment processes (alkaline wet oxidation and enzyme treatment with laccase) on lignocellulosic materials for applications in particleboards and fiberboards. Wheat straw and beech fibers...... treatment gave a more reactive surface than alkaline wet oxidation for wheat straw, whereas the opposite was observed for beech. Fourier transform infrared (FT-IR) spectroscopy showed an almost complete loss of the ester carbonyl stretching signal and the corresponding C-C-O stretching in wet...

  9. SiO2 coating of silver nanoparticles by photoinduced chemical vapor deposition

    International Nuclear Information System (INIS)

    Boies, Adam M; Girshick, Steven L; Roberts, Jeffrey T; Zhang Bin; Nakamura, Toshitaka; Mochizuki, Amane

    2009-01-01

    Gas-phase silver nanoparticles were coated with silicon dioxide (SiO 2 ) by photoinduced chemical vapor deposition (photo-CVD). Silver nanoparticles, produced by inert gas condensation, and a SiO 2 precursor, tetraethylorthosilicate (TEOS), were exposed to vacuum ultraviolet (VUV) radiation at atmospheric pressure and varying temperatures. The VUV photons dissociate the TEOS precursor, initiating a chemical reaction that forms SiO 2 coatings on the particle surfaces. Coating thicknesses were measured for a variety of operation parameters using tandem differential mobility analysis and transmission electron microscopy. The chemical composition of the particle coatings was analyzed using energy dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The highest purity films were produced at 300-400 0 C with low flow rates of additional oxygen. The photo-CVD coating technique was shown to effectively coat nanoparticles and limit core particle agglomeration at concentrations up to 10 7 particles cm -3 .

  10. Chemical nature of catalysts of oxide nanoparticles in environment ...

    Indian Academy of Sciences (India)

    alloy or cobalt nanoparticles having fcc structure, but the rate of reduction is relatively less in ... dissociation of H2 on the metallic clusters once their size is .... 20 wt.% substitution of cobalt/nickel by copper in the aque- ous saturated solution of ...

  11. Optimisation of electronic interface properties of a-Si:H/c-Si hetero-junction solar cells by wet-chemical surface pre-treatment

    Energy Technology Data Exchange (ETDEWEB)

    Angermann, H. [Hahn-Meitner-Institut, Abt. Siliziumphotovoltaik, Kekulestrasse 5, D-12489 Berlin (Germany)], E-mail: angermann@hmi.de; Korte, L.; Rappich, J.; Conrad, E.; Sieber, I.; Schmidt, M. [Hahn-Meitner-Institut, Abt. Siliziumphotovoltaik, Kekulestrasse 5, D-12489 Berlin (Germany); Huebener, K.; Hauschild, J. [Freie Universitaet Berlin, FB Physik, Arnimallee 14, 14195 Berlin (Germany)

    2008-08-30

    The relation between structural imperfections at structured silicon surfaces, energetic distribution of interface state densities, recombination loss at a-Si:H/c-Si interfaces and solar cell characteristics have been intensively investigated using non-destructive, surface sensitive techniques, surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and electron microscopy (SEM). Sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of Si(111) pyramids. Special wet-chemical smoothing and oxide removal procedures for structured substrates were developed, in order to reduce the preparation-induced surface micro-roughness and density of electronically active defects. H-termination and passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological process. We achieved significantly lower micro-roughness, densities of surface states D{sub it}(E) and recombination loss at a-Si:H/c-Si interfaces on wafers with randomly distributed pyramids, compared to conventional pre-treatments. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H/c-Si/BSF/Al), the c-Si surface becomes part of the a-Si:H/c-Si interface, whose recombination activity determines cell performance. With textured substrates, the smoothening procedure results in a significant increase of short circuit current, fill factor and efficiency.

  12. Optimisation of electronic interface properties of a-Si:H/c-Si hetero-junction solar cells by wet-chemical surface pre-treatment

    International Nuclear Information System (INIS)

    Angermann, H.; Korte, L.; Rappich, J.; Conrad, E.; Sieber, I.; Schmidt, M.; Huebener, K.; Hauschild, J.

    2008-01-01

    The relation between structural imperfections at structured silicon surfaces, energetic distribution of interface state densities, recombination loss at a-Si:H/c-Si interfaces and solar cell characteristics have been intensively investigated using non-destructive, surface sensitive techniques, surface photovoltage (SPV) and photoluminescence (PL) measurements, atomic force microscopy (AFM) and electron microscopy (SEM). Sequences of wet-chemical oxidation and etching steps were optimised with respect to the etching behaviour of Si(111) pyramids. Special wet-chemical smoothing and oxide removal procedures for structured substrates were developed, in order to reduce the preparation-induced surface micro-roughness and density of electronically active defects. H-termination and passivation by wet-chemical oxides were used to inhibit surface contamination and native oxidation during the technological process. We achieved significantly lower micro-roughness, densities of surface states D it (E) and recombination loss at a-Si:H/c-Si interfaces on wafers with randomly distributed pyramids, compared to conventional pre-treatments. For amorphous-crystalline hetero-junction solar cells (ZnO/a-Si:H/c-Si/BSF/Al), the c-Si surface becomes part of the a-Si:H/c-Si interface, whose recombination activity determines cell performance. With textured substrates, the smoothening procedure results in a significant increase of short circuit current, fill factor and efficiency

  13. Fabrication and durable antibacterial properties of 3D porous wet electrospun RCSC/PCL nanofibrous scaffold with silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Mei; Lin, Han [Alan G. MacDiarmid Laboratory, College of Chemistry, Jilin University, Changchun 130012 (China); Wang, Yilong [College of Quartermaster Technology, Jilin University, Changchun, 130062 (China); Yang, Guang [Norman Bethune First Hospital, Jilin University, Changchun 130021 (China); Zhao, He [Alan G. MacDiarmid Laboratory, College of Chemistry, Jilin University, Changchun 130012 (China); Sun, Dahui, E-mail: sundahui1971@sina.com [Norman Bethune First Hospital, Jilin University, Changchun 130021 (China)

    2017-08-31

    Highlights: • Ranachensinensis skin collagen (RCSC) was used with molecular weight 105∼250KDa. • Wet electrospinning was successfully improved and was used to produce 3D porous structure materials with about 90% porosity. • AgNPs was loaded in AgNPs dispersion liquid. - Abstract: Electrospunnanofibers are used as three-dimensional (3D) scaffold materials that can alter cell attachment and cell proliferation, change the antibacterial properties of materials, and can be used as wound dressings. But the fabrication of porous 3D scaffold structure and the antibacterial properties enhancing are challenges remained to improve. With the states here, a Ranachensinensis skin collagen (RCSC)/poly(ε-caprolactone) (PCL)AgNP-loaded3D nanofiber scaffold is fabricated as a wound dressing material by using an improved wet electrospinning method (blending). The nanoscale of the AgNPs is proved. The 3D porous morphologies of the materials with different AgNP loadings, are determined with field emission scanning electron microscopy (FESEM) and the presence and uniformity distribution of AgNPs is confirmed by Energy dispersive X-ray (EDX) spectroscopy. The silver-ion release rates, antibacterial properties, and cytotoxicities of dressing materials with different AgNP contents are evaluated using ICP-AES, the zone inhibition method, and MTT testing. These results showed that the improved wet electrospun is an effective way to fabricate AgNP loaded 3D scaffold materials with porous structure and nearly 90% porosity and the presence of AgNPs in dressing materials strengthen the antibacterial properties. The RCSC/PCL 3D scaffold materials containing 2.0%AgNP would be promising for dressing materials application nearly without cytotoxicities.

  14. Synthesis of Mn3O4 nanoparticles via chemical precipitation approach for supercapacitor application

    International Nuclear Information System (INIS)

    Gnana Sundara Raj, Balasubramaniam; Asiri, Abdullah M.; Wu, Jerry J.; Anandan, Sambandam

    2015-01-01

    Highlights: • Facile synthesis of Mn 3 O 4 nanoparticles at room temperature via simple chemical precipitation method. • Fabricated supercapacitor device shows maximum specific capacitance in 1 M Na 2 SO 4 . • 77% of specific capacitance is retained even after 1000 cycles. - Abstract: A simple chemical precipitation method has been used for the preparation of Mn 3 O 4 nanoparticles at room temperature. The crystal structure and morphology studies of the resulting Mn 3 O 4 nanoparticles were characterized by powder X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), N 2 adsorption and desorption and X-ray photoelectron spectroscopy (XPS). The electrochemical properties of the Mn 3 O 4 nanoparticles were then investigated using cyclic voltammetry (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS) analysis. The supercapacitive properties of Mn 3 O 4 nanoparticles in the presence of 1 M Na 2 SO 4 exhibited a high specific capacitance of 322 F g −1 at a current density of 0.5 mA cm −2 in the potential range from −0.1 to +0.9 V and about 77% of the initial capacitance was retained after 1000 cycles, indicating that the Mn 3 O 4 electrode owns a good electrochemical stability and capacitance retention capability. The results suggest that the obtained Mn 3 O 4 nanoparticles is a promising electrode material for supercapacitor applications

  15. Ultrasonic-assisted chemical reduction synthesis and structural characterization of copper nanoparticles

    Science.gov (United States)

    Anh-Nga, Nguyen T.; Tuan-Anh, Nguyen; Thanh-Quoc, Nguyen; Ha, Do Tuong

    2018-04-01

    Copper nanoparticles, due to their special properties, small dimensions and low-cost preparation, have many potential applications such as in optical, electronics, catalysis, sensors, antibacterial agents. In this study, copper nanoparticles were synthesized by chemical reduction method with different conditions in order to investigate the optimum conditions which gave the smallest (particle diameter) dimensions. The synthesis step used copper (II) acetate salt as precursor, ascorbic acid as reducing agent, glycerin and polyvinylpyrrolidone (PVP) as protector and stabilizer. The assistance of ultrasonic was were considered as the significant factor affecting the size of the synthesized particles. The results showed that the copper nanoparticles have been successfully synthesized with the diameter as small as 20-40 nm and the conditions of ultrasonic waves were 48 kHz of frequency, 20 minutes of treated time and 65-70 °C of temperature. The synthesized copper nanoparticles were characterized by optical absorption spectrum, scanning electron microscopy (SEM), and Fourier Transform Infrared Spectrometry.

  16. The effect of biologically and chemically synthesized silver nanoparticles (AgNPs) on biofilm formation

    Science.gov (United States)

    Chojniak, Joanna; Biedroń, Izabela; Mendrek, Barbara; Płaza, Grażyna

    2017-11-01

    Bionanotechnology has emerged up as integration between biotechnology and nanotechnology for developing biosynthetic and environmental-friendly technology for synthesis of nanomaterials. Different types of nanomaterials like copper, zinc, titanium, magnesium, gold, and silver have applied in the various industries but silver nanoparticles have proved to be most effective against bacteria, viruses and eukaryotic microorganisms. The antimicrobial property of silver nanoparticles are widely known. Due to strong antibacterial property silver nanoparticles are used, e.g. in clothing, food industry, sunscreens, cosmetics and many household and environmental appliances. The aim of the study was to compare the effect of silver nanoparticles (AgNPs) synthesized biologically and chemically on the biofilm formation. The biofilm was formed by the bacteria isolated from the water supply network. The commonly used crystal violet assay (CV) was applied for biofilm analysis. In this study effect of biologically synthesized Ag-NPs on the biofilm formation was evaluated.

  17. Controlling “chemical nose” biosensor characteristics by modulating gold nanoparticle shape and concentration

    Directory of Open Access Journals (Sweden)

    Mohit S. Verma

    2015-09-01

    Full Text Available Conventional lock-and-key biosensors often only detect a single pathogen because they incorporate biomolecules with high specificity. “Chemical nose” biosensors are overcoming this limitation and identifying multiple pathogens simultaneously by obtaining a unique set of responses for each pathogen of interest, but the number of pathogens that can be distinguished is limited by the number of responses obtained. Herein, we use a gold nanoparticle-based “chemical nose” to show that changing the shapes of nanoparticles can increase the number of responses available for analysis and expand the types of bacteria that can be identified. Using four shapes of nanoparticles (nanospheres, nanostars, nanocubes, and nanorods, we demonstrate that each shape provides a unique set of responses in the presence of different bacteria, which can be exploited for enhanced specificity of the biosensor. Additionally, the concentration of nanoparticles controls the detection limit of the biosensor, where a lower concentration provides better detection limit. Thus, here we lay a foundation for designing “chemical nose” biosensors and controlling their characteristics using gold nanoparticle morphology and concentration. Keywords: Morphology, Color change, Staphylococcus aureus, Point-of-care, Nanocubes, Nanorods

  18. Tribochemical interaction between nanoparticles and surfaces of selective layer during chemical mechanical polishing

    International Nuclear Information System (INIS)

    Ilie, Filip

    2013-01-01

    Nanoparticles have been widely used in polish slurries such as those in the chemical mechanical polishing (CMP) process. For understanding the mechanisms of CMP, an atomic force microscope (AFM) is used to characterize polished surfaces of selective layers, after a set of polishing experiments. To optimize the CMP polishing process, one needs to get information on the interaction between the nano-abrasive slurry nanoparticles and the surface of selective layer being polished. The slurry used in CMP process of the solid surfaces is slurry with large nanoparticle size colloidal silica sol nano-abrasives. Silica sol nano-abrasives with large nanoparticle are prepared and characterized by transmission electron microscopy, particles colloidal size, and Zeta potential in this paper. The movement of nanoparticles in liquid and the interaction between nanoparticles and solid surfaces coating with selective layer are very important to obtain an atomic alloy smooth surface in the CMP process. We investigate the nanoparticle adhesion and removal processes during CMP and post-CMP cleaning. The mechanical interaction between nanoparticles and the wafer surface was studied using a microcontact wear model. This model considers the nanoparticle effects between the polishing interfaces during load balancing. Experimental results on polishing and cleaning are compared with numerical analysis. This paper suggests that during post-CMP cleaning, a combined effort in chemical and mechanical interaction (tribochemical interactions) would be effective in removal of small nanoparticles during cleaning. For large nanoparticles, more mechanical forces would be more effective. CMP results show that the removal rate has been improved to 367 nm/min and root mean square (RMS) of roughness has been reduced from 4.4 to 0.80 nm. Also, the results show that the silica sol nano-abrasives about 100 nm are of higher stability (Zeta potential is −65 mV) and narrow distribution of nanoparticle

  19. Physico-chemical separation process of nanoparticles in cosmetic formulations

    International Nuclear Information System (INIS)

    Marín, R. R. Retamal; Babick, F.; Stintz, M.

    2017-01-01

    Understanding the world of nanoparticles, especially their interactions with the environment, begins with their correct detection and successive quantification. To achieve this purpose, one needs to perform correctly developed standard operating procedures (SOPs). Furthermore, the study of nanoparticles frequently requires their characterisation in complex media (e.g. in cosmetic formulations). In this study, a set of sample preparation procedures for the detection and extraction of NMs in emulsion-based formulations is proposed and their performance for model and real-life products is discussed. A separation or extraction of lipid phases is achieved by means of organic solvents. The polarity of the lipid phases is decisive for selecting an optimum solvent. The use of the Hansen Solubility Parameters (HSP) may clearly support this decision. (paper)

  20. Synthesis of Tungsten Diselenide Nanoparticles by Chemical Vapor Condensation Method

    Directory of Open Access Journals (Sweden)

    Oleg V. Tolochko

    2015-09-01

    Full Text Available Crystalline tungsten diselenide (WSe2 nanoparticles have been synthesized by a gas phase reaction using tungsten hexacarbonyl and elemental selenium as precursors. The WSe2 nanoparticle morphology varies from the spherical shape to flake-like layered structures. Mean size in smaller dimension are less than 5 nm and the number of layers decreased linearly with decreasing of reaction time and concentration of carbonyl in the gas phase. The mean value of interlayer distance in <0001> direction is comparable with the microscopic values. The selenium-to-tungsten atomic ratios of 2.07, 2.19 and 2.19 were determined respectively, approach to the stoichiometric ratio of 2:1. Main impurities are oxygen and carbon and strongly interrelated with carbonyl concentration in the gas phase.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7356

  1. Porphyrins as SERRS spectral probes of chemically functionalized Ag nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Šišková, Karolína; Vlčková, B.; Turpin, P. Y.; Thorel, A.; Grosjean, A.

    2008-01-01

    Roč. 48, č. 1 (2008), s. 44-52 ISSN 0924-2031. [International Conference on Advanced Vibrational Spectroscopy (ICAVS-4) /4./. Corfu, 10.06.2007-15.06.2007] R&D Projects: GA ČR GA203/07/0717 Institutional research plan: CEZ:AV0Z40500505 Keywords : SERRS * citrate-modified Ag nanoparticles * laser ablation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.810, year: 2008

  2. Electrocatalysis of chemically synthesized noble metal nanoparticles on carbon electrodes

    DEFF Research Database (Denmark)

    Zhang, Ling; Ulstrup, Jens; Zhang, Jingdong

    Noble metal nanoparticles (NPs), such as platinum (Pt) and palladium (Pd) NPs are promising catalysts for dioxygen reduction and oxidation of molecules such as formic acid and ethanol in fuel cells. Carbon nanomaterials are ideal supporting materials for electrochemical catalysts due to their good...... by electrochemical SPM. This study offers promise for development of new high-efficiency catalyst types with low-cost for fuel cell technology...

  3. Evaluation of Biological Activities of Chemically Synthesized Silver Nanoparticles

    International Nuclear Information System (INIS)

    Mostafa, A. A.; Solkamy, E.N.; Sayed, Sh. R. M.; Khan, M.; Shaik, M.R.; Al-Warthan, A.; Adil, S.F.

    2015-01-01

    Silver nanoparticles were synthesized by the earlier reported methods. The synthesized nanoparticles were characterized using ultraviolet-visible spectrophotometry (UV/Vis), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), and X-ray powder diffraction (XRD). The synthesized materials were also evaluated for their antibacterial activity against Gram positive and Gram negative bacterial strains. TEM micrograph showed the spherical morphology of AgNPs with size range of 40-60 nm. The synthesized nanoparticles showed a strong antimicrobial activity and their effect depends upon bacterial strain as AgNPs exhibited greater inhibition zone for Pseudomonas aeruginosa (19.1 mm) followed by Staphylococcus aureus (14.8?mm) and S. pyogenes (13.6 mm) while the least activity was observed for Salmonella typhi (12.5 mm) at concentration of 5 μg/disc. The minimum inhibitory concentration (MIC) of AgNPs against S. aureus was 2.5 μg/disc and less than 2.5 μg/disc for P. aeruginosa. These results suggested that AgNPs can be used as an effective antiseptic agent for infectious control in medical field.

  4. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    Energy Technology Data Exchange (ETDEWEB)

    Bjerre, A B; Skammelsen Schmidt, A

    1997-02-01

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates `losses` of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation.

  5. Development of chemical and biological processes for production of bioethanol. Optimization of the wet oxidation process and characterization of products

    International Nuclear Information System (INIS)

    Bjerre, A.B.; Skammelsen Schmidt, A.

    1997-02-01

    The combination of the wet oxidation pretreatment process and alkaline hydrolysis was investigated in order to efficiently solubilize the hemicellulose, degrade the lignin, and open the solid crystalline cellulose structure of wheat straw lignocellulose without generating fermentation inhibitors. The effects of temperature, oxygen pressure, reaction time, and concentration of straw were evaluated. The degree of lignin degradation and hemicellulose solubilization increased with the reaction temperature and time. The optimum conditions were 15 minutes at 185 deg. C, producing 9.8 g/L hemicellulose. For quantification of the solubilized hemicellulose the best overall acid hydrolysis was obtained by treatment with 4 %w/v sulfuric acid for 10 minutes. The Aminex HPX-87H column was less sensitive towards impurities than the Aminex HPX-87P column. HPX-87H gave improved recovery and reproducibility, and was chosen for routine quantification of hydrolyzed hemicellulose sugars. The purity of the solid cellulose fraction also improved with higher temperature. The optimum condition for obtaining enzymatic convertible cellulose (90%) was 10 minutes at 170 deg. C using a high carbonate concentration. The hemicellulose yield and recovery were significantly reduced under these conditions indicating that a simultaneous optimal utilization of the hemicellulose and cellulose was difficult. The oxygen pressure and sodium carbonate concentration had little effect on the solubilization of hemicellulose, however, by combining wet oxidation with alkaline hydrolysis the formation of 2-furfural, a known microbial inhibitor, was minimal. Much more hemicellulose and lignin were solubilized from the straw by wet oxidation than by steaming(an alternative process). More cellulose was solubilized (and degraded) by steaming than by wet oxidation. Overall carbohydrates 'losses' of 20.1% for steaming and 16.2% for wet oxidation were found. More 2-furfural was formed by steaming than by wet oxidation

  6. High-resolution chemical imaging of gold nanoparticles using hard x-ray ptychography

    DEFF Research Database (Denmark)

    Hoppe, R.; Reinhardt, J.; Hofmann, G.

    2013-01-01

    We combine resonant scattering with (ptychographic) scanning coherent diffraction microscopy to determine the chemical state of gold nanoparticles with high spatial resolution. Ptychographic images of the sample are recorded for a series of energies around the gold L3 absorption edge. From these ...

  7. Rapid synthesis of silver nanoparticles from Polylthia longifolia leaves

    Directory of Open Access Journals (Sweden)

    Tollamadugu Nagavenkata

    2012-10-01

    Full Text Available Objective: Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are quite often toxic and flammable. In this research article we present a simple and eco-friendly biosynthesis of silver nanoparticles using P. longifolia leaf extract as reducing agent. Methods: Characterization using UV-Vis spectrophotometry, Transmission Electron Microscopy (TEM was performed. Results: TEM showed the formation of silver nanoparticles with an average size of 57 nm. Conclusions: P. longifolia demonstrated strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions (Ag+ to Ag0. Biological methods are a good competent for the chemical procedures, which are enviro- friendly and convenient.

  8. Preparation of palladium nanoparticles on alumina surface by chemical co-precipitation method and catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Avvaru Praveen; Kumar, B. Prem; Kumar, A.B.V. Kiran; Huy, Bui The [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Lee, Yong-Ill, E-mail: yilee@changwon.ac.kr [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Facile synthesis of palladium nanoparticles on alumina surface. Black-Right-Pointing-Pointer The surface morphology and properties of the nanocrystalline powders were characterized. Black-Right-Pointing-Pointer The catalytic activities of palladium nanoparticles were investigated. - Abstract: The present work reports a chemical co-precipitation process to synthesize palladium (Pd) nanoparticles using alumina as a supporting material. The optimized temperature for the formation of nanocrystalline palladium was found to be 600 Degree-Sign C. The X-ray diffraction (XRD) and Raman spectroscopy were used to study the chemical nature of the Pd in alumina matrix. The surface morphology and properties of the nanocrystalline powders were examined using thermogravimetric analysis (TG-DTA), XRD, Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The calcinations in different atmospheres including in the inert medium forms the pure nano Pd{sup 0} while in the atmospheric air indicates the existence pure Pd{sup 0} along with PdO nanoparticles. The catalytic activities of the as-synthesized nanocrystalline Pd nanoparticles in the alumina matrix were investigated in Suzuki coupling, Hiyama cross-coupling, alkene and alkyne hydrogenation, and aerobic oxidation reactions.

  9. Observing single molecule chemical reactions on metal nanoparticles.

    Energy Technology Data Exchange (ETDEWEB)

    Emory, S. R. (Steven R.); Ambrose, W. Patrick; Goodwin, P. M. (Peter M); Keller, Richard A.

    2001-01-01

    We report the study of the photodecomposition of single Rhodamine 6G (R6G) dye molecules adsorbed on silver nanoparticles. The nanoparticles were immobilized and spatially isolated on polylysine-derivatized glass coverslips, and confocal laser microspectroscopy was used to obtain surface-enhanced Raman scattering (SERS) spectra from individual R6G molecules. The photodecomposition of these molecules was observed with 150-ms temporal resolution. The photoproduct was identified as graphitic carbon based on the appearance of broad SERS vibrational bands at 1592 cm{sup -1} and 1340 cm{sup -1} observed in both bulk and averaged single-molecule photoproduct spectra. In contrast, when observed at the single-molecule level, the photoproduct yielded sharp SERS spectra. The inhomogeneous broadening of the bulk SERS spectra is due to a variety of photoproducts in different surface orientations and is a characteristic of ensemble-averaged measurements of disordered systems. These single-molecule studies indicate a photodecomposition pathway by which the R6G molecule desorbs from the metal surface, an excited-state photoreaction occurs, and the R6G photoproduct(s) readsorbs to the surface. A SERS spectrum is obtained when either the intact R6G or the R6G photoproduct(s) are adsorbed on a SERS-active site. This work further illustrates the power of single-molecule spectroscopy (SMS) to reveal unique behaviors of single molecules that are not discernable with bulk measurements.

  10. Chemical synthesis, characterization and evaluation of antimicrobial properties of Cu and its oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Moshalagae Motlatle, Abesach, E-mail: AMotlatle@csir.co.za; Kesavan Pillai, Sreejarani, E-mail: skpillai@csir.co.za; Rudolf Scriba, Manfred, E-mail: MRscriba@csir.co.za; Sinha Ray, Suprakas, E-mail: Rsuprakas@csir.co.za [Council for Scientific and Industrial Research, DST/CSIR Nanotechnology Innovation Centre, National Centre for Nano-Structured Materials (South Africa)

    2016-10-15

    Cu nanoparticles were synthesized using low-temperature aqueous reduction method at pH 3, 5, 7, 9 and 11 in presence of ascorbic acid and polyvinylpyrrolidone. The nanoparticles were characterized using transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. Results demonstrated a strong dependence of synthesis pH on the size, shape, chemical composition and structure of Cu nanoparticles. While lower pH conditions of 3 and 5 produced Cu{sup 0}, higher pH levels (more than 7) led to the formation of Cu{sub 2}O/CuO nanoparticles. The reducing capacity of ascorbic acid, capping efficiency of PVP and the resulting particle sizes were strongly affected by solution pH. The results of in vitro disk diffusion tests showed excellent antimicrobial activity of Cu{sub 2}O/CuO nanoparticles against a mixture of bacterial strains (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa), indicating that the size as well as oxidation state of Cu contributes to the antibacterial efficacy. The results indicate that varying synthesis pH is a strategy to tailor the composition, structure and properties of Cu nanoparticles.

  11. Design of a versatile chemical assembly method for patterning colloidal nanoparticles

    International Nuclear Information System (INIS)

    Choi, J H; Adams, S M; Ragan, R

    2009-01-01

    Poly(methyl methacrylate) (PMMA) domains in phase-separated polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer thin films were chemically modified for controlled placement of solution synthesized Au nanoparticles having a mean diameter of 24 nm. Colloidal Au nanoparticles functionalized with thioctic acid were immobilized on amine functionalized PMMA domains on the PS-b-PMMA template using 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride linking chemistry and N-hydroxy sulfosuccinimide stabilizer. Atomic force microscopy and scanning electron microscopy images demonstrated immobilization of Au nanoparticles commensurate with PMMA domains. Nanoparticles form into clusters of single particles, dimers, and linear chains as directed by the PMMA domain size and shape. Capillary forces influence the spacing between Au nanoparticles on PMMA domains. Inter-particle spacings below 3 nm were achieved and these assemblies of closely spaced nanoparticle clusters are expected to exhibit strong localized electromagnetic fields. Thus, these processes and material systems provide an experimental platform for studying resonantly enhanced excitations of surface plasmons as a function of material and geometric structure as well as utilization in catalytic applications.

  12. Influences of ultrasonic irradiation on the morphology and structure of nanoporous Co nanoparticles during chemical dealloying

    Directory of Open Access Journals (Sweden)

    Hui Li

    2016-12-01

    Full Text Available The Co-61.8 wt% Al nanoparticles of 45 nm were prepared by hydrogen plasma-metal reaction (HPMR method. The nanoparticles display core shell structure with Al13Co4 and CoAl core and aluminum oxide shell (about 2 nm. Under ultrasonic irradiation, nanoporous fcc-Co nanoparticles were produced successfully by chemically dealloying the Co-Al nanoparticles at room temperature, whereas, without ultrasonic irradiation CoAl phase could hardly react with sodium hydroxide solution. At 323 K the Co-Al nanoparticles could be dealloyed to fcc-Co and hcp-Co phases even without ultrasonic irradiation. The surface area of the dealloyed nanoparticles under ultrasonic irradiation was larger than that of the dealloyed sample without ultrasonic irradiation at the same temperature. It is believed that the microjet and shock-wave induced by ultrasonic irradiation give rise to particles size reduction, interparticle collision and surface cleaning, and accelerate the dealloying process and the phase transformation.

  13. Role of noble metal nanoparticles in DNA base damage and catalysis: a radiation chemical investigation

    International Nuclear Information System (INIS)

    Sharma, Geeta K.

    2011-01-01

    In the emerging field of nanoscience and nanotechnology, tremendous focus has been made by researcher to explore the applications of nanomaterials for human welfare by converting the findings into technology. Some of the examples have been the use of nanoparticles in the field of opto-electronic, fuel cells, medicine and catalysis. These wide applications and significance lies in the fact that nanoparticles possess unique physical and chemical properties very different from their bulk precursors. Numerous methods for the synthesis of noble nanoparticles with tunable shape and size have been reported in literature. The goal of our group is to use different methods of synthesis of noble metal nanoparticles (Au, Ag, Pt and Pd) and test their protective/damaging role towards DNA base damage induced by ionizing radiation (Au and Ag) and to test the catalytic activity of nanoparticles (Pt and Pd) in certain known organic synthesis/electron transfer reactions. Using radiation chemical techniques such as pulse radiolysis and steady state radiolysis complemented by the product analysis using HPLC/LC-MS, a detailed mechanism for the formation of transient species, kinetics leading to the formation of stable end products is studied in the DNA base damage induced by ionizing radiation in presence and absence of Au and Ag nanoparticles. Unraveling the complex interaction between catalysts and reactants under operando conditions is a key step towards gaining fundamental insight in catalysis. The catalytic activity of Pt and Pd nanoparticles in electron transfer and Suzuki coupling reactions has been determined. Investigations are currently underway to gain insight into the interaction between catalysts and reactants using time resolved spectroscopic measurements. These studies will be detailed during the presentation. (author)

  14. Chemical and thermal stability of core-shelled magnetite nanoparticles and solid silica

    Science.gov (United States)

    Cendrowski, Krzysztof; Sikora, Pawel; Zielinska, Beata; Horszczaruk, Elzbieta; Mijowska, Ewa

    2017-06-01

    Pristine nanoparticles of magnetite were coated by solid silica shell forming core/shell structure. 20 nm thick silica coating significantly enhanced the chemical and thermal stability of the iron oxide. Chemical and thermal stability of this structure has been compared to the magnetite coated by mesoporous shell and pristine magnetite nanoparticles. It is assumed that six-membered silica rings in a solid silica shell limit the rate of oxygen diffusion during thermal treatment in air and prevent the access of HCl molecules to the core during chemical etching. Therefore, the core/shell structure with a solid shell requires a longer time to induce the oxidation of iron oxide to a higher oxidation state and, basically, even strong concentrated acid such as HCl is not able to dissolve it totally in one month. This leads to the desired performance of the material in potential applications such as catalysis and environmental protection.

  15. Synthesis and characterization of chemically ordered FePt magnetic nano-particles

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasa Rao, K. [Centre for Materials for Electronics Technology (C-MET), IDA phase-III, Cherlapally, Hyderabad 500 051 (India); Balaji, T., E-mail: theerthambalaji@yahoo.co [Centre for Materials for Electronics Technology (C-MET), IDA phase-III, Cherlapally, Hyderabad 500 051 (India); Lingappa, Y. [Department of Chemistry, Sri Venkateswara University, Tirupati 517 502 (India); Reddy, M.R.P.; Kumar, Arbind; Prakash, T.L. [Centre for Materials for Electronics Technology (C-MET), IDA phase-III, Cherlapally, Hyderabad 500 051 (India)

    2010-08-15

    Monodispersed FePt alloy magnetic nano-particles are prepared by reduction of platinum acetyl acetonate and iron acetyl acetonate salts together in the presence of oleic acid and oleyl amine stabilizers by polyol process. The particle size of FePt is in the range of 2-3 nm confirmed by transmission electron microscopy (TEM). As-synthesized FePt nano-particles are chemically disordered with face centre cubic (fcc) structure where as after vacuum annealing these particles changed to face centre tetragonal (fct) ordered structure confirmed by the X-ray diffraction technique. Magnetic coercivity of 5.247 KOe was observed for fct structure.

  16. New insights into the mixing of gold and copper in a nanoparticle from a structural study of Au-Cu nanoalloys synthesized via a wet chemistry method and pulsed laser deposition.

    Science.gov (United States)

    Prunier, Hélène; Nelayah, Jaysen; Ricolleau, Christian; Wang, Guillaume; Nowak, Sophie; Lamic-Humblot, Anne-Félicie; Alloyeau, Damien

    2015-11-14

    Gold-copper nanoparticles (Au-Cu NPs) were elaborated by both chemical (polyol reduction method) and physical (laser deposition) routes. The size, composition and crystal structure of these bimetallic nanoalloys were then characterized by aberration corrected transmission electron microscopy (TEM). Using a one-pot polyol method, Au-Cu nanocubes (NCs) with nominal compositions Au3Cu and AuCu3 were synthesized. The size and composition of the NCs were tuned by varying the amount and the ratio of Au(iii) and Cu(ii) ions used as metallic precursors in the reaction. While the particle shape and size were well-controlled, single particle X-ray spectroscopy showed that, irrespective of the targeted compositions, the Cu content in all NCs was about 11-12 at%, i.e. in both samples, the real composition was different from the nominal one. This was ascribed to an incomplete alloying of the two constituent metals of the alloy in the cubes due to different reduction kinetics of the two metallic precursors. To shed light on the alloying of gold and copper at the nanoscale, Au-Cu NPs with targeted compositions Au3Cu and AuCu3 were deposited on amorphous carbon by laser ablation of two monometallic sources, and their structural properties were studied by TEM. These studies show that Au-Cu nanoalloys were synthesized in both samples and that the complete mixing of Au and Cu atoms achieved with this synthesis technique led to the production of Au-Cu NPs with well-controlled compositions. These results constitute a first but major step towards a complete understanding of the details of kinetics and thermodynamics determining the mixing of gold and copper atoms at the nanoscale. Such an understanding is essential for producing Au-Cu bimetallic nanoalloys with well-defined structural properties via wet chemical synthesis.

  17. Visible-light sensitization of TiO2 photocatalysts via wet chemical N-doping for the degradation of dissolved organic compounds in wastewater treatment: a review

    Science.gov (United States)

    Zhang, Wei; Jia, Baoping; Wang, Qiuze; Dionysiou, Dionysois

    2015-05-01

    Increased pollution of ground and surface water and emerging new micropollutants from a wide variety of industrial, municipal, and agricultural sources has increased demand on the development of innovative new technologies and materials whereby challenges associated with the provision of safe potable water can be addressed. Heterogeneous photocatalysis using visible-light sensitized TiO2 photocatalysts has attracted a lot of attention as it can effectively remove dissolved organic compound in water without generating harmful by-products. On this note, recent progress on visible-light sensitive TiO2 synthesis via wet chemical N-doping method is reviewed. In a typical visible-light sensitive TiO2 preparation via wet chemical methods, the chemical (e.g., N-doping content and states) and morphological properties (e.g., particle size, surface area, and crystal phase) of TiO2 in as-prepared resultants are sensitively dependent on many experimental variables during the synthesis. This has also made it very difficult to provide a universal guidance at this stage with a certainty for each variable of N-doping preparation. Instead of one-factor-at-a-time style investigation, a statistically valid parameter optimization investigation for general optima of photocatalytic activity will be certainly useful. Optimization of the preparation technique is envisaged to be beneficial to many environmental applications, i.e., dissolved organic compounds removal in wastewater treatment.

  18. Visible-light sensitization of TiO2 photocatalysts via wet chemical N-doping for the degradation of dissolved organic compounds in wastewater treatment: a review

    International Nuclear Information System (INIS)

    Zhang, Wei; Jia, Baoping; Wang, Qiuze; Dionysiou, Dionysois

    2015-01-01

    Increased pollution of ground and surface water and emerging new micropollutants from a wide variety of industrial, municipal, and agricultural sources has increased demand on the development of innovative new technologies and materials whereby challenges associated with the provision of safe potable water can be addressed. Heterogeneous photocatalysis using visible-light sensitized TiO 2 photocatalysts has attracted a lot of attention as it can effectively remove dissolved organic compound in water without generating harmful by-products. On this note, recent progress on visible-light sensitive TiO 2 synthesis via wet chemical N-doping method is reviewed. In a typical visible-light sensitive TiO 2 preparation via wet chemical methods, the chemical (e.g., N-doping content and states) and morphological properties (e.g., particle size, surface area, and crystal phase) of TiO 2 in as-prepared resultants are sensitively dependent on many experimental variables during the synthesis. This has also made it very difficult to provide a universal guidance at this stage with a certainty for each variable of N-doping preparation. Instead of one-factor-at-a-time style investigation, a statistically valid parameter optimization investigation for general optima of photocatalytic activity will be certainly useful. Optimization of the preparation technique is envisaged to be beneficial to many environmental applications, i.e., dissolved organic compounds removal in wastewater treatment

  19. Morphology-controlled SWCNT/polymeric microsphere arrays by a wet chemical self-assembly technique and their application for sensors

    International Nuclear Information System (INIS)

    Huang Xingjiu; Li Yue; Im, Hyung-Soon; Yarimaga, Oktay; Kim, Ju-Hyun; Jang, Doon-Yoon; Cho, Sung-Oh; Cai Weiping; Choi, Yang-Kyu

    2006-01-01

    Large-scale morphology-controlled SWCNT/polymeric microsphere arrays can be obtained by a wet chemical self-assembly technique. The loading of SWCNTs, the length of SWCNTs, and the size and nature of polymeric microspheres can easily be controlled. Similar results can also be reached using this method for MWCNTs. In both types of CNTs, they form an interesting interactive 'net' structure on spheres and sphere joints. The SWCNT/PS-modified Au electrode was used for detection of uric acid by cyclic voltammetry and single-potential time-based techniques. The preliminary results show that the modified electrode presents good sensitivity and stability to uric acid

  20. Structure and magnetic properties of Zn1-xCoxO single-crystalline nanorods synthesized by a wet chemical method

    International Nuclear Information System (INIS)

    Wang Hao; Wang, H B; Yang, F J; Chen, Y; Zhang, C; Yang, C P; Li, Q; Wong, S P

    2006-01-01

    A novel approach for the synthesis of cobalt-doped ZnO single-crystalline nanorods based on a wet chemical reaction has been developed. The as-doped ZnO nanorods have a length between 0.3 and 0.6 μm and a diameter between 30 and 60 nm. Structure and composition analyses indicate that the cobalt is incorporated into the ZnO lattice, forming a solid solution without any precipitation. Magnetic property measurements reveal that there is room-temperature ferromagnetism in the Zn 1-x Co x O nanorods with T c higher than 300 K

  1. Effect of chemically and biologically synthesized Ag nanoparticles on the algae growth inhibition

    Science.gov (United States)

    Anna, Mražiková; Oksana, Velgosová; Jana, Kavuličová

    2017-12-01

    Over the past few years green methods for preparation of silver nanoparticles has become necessary due to its friendly influence on ecosystem. In the present work antimicrobial properties of biologically synthesized silver nanoparticles (Bio-AgNPs) using green algae extract and chemically synthesized silver nanoparticles (Chem-AgNPs) using sodium citrate against algae Parachlorella kessleri is investigated. Both used Bio-AgNPs and Chem-AgNPs exhibit long-term stability as demonstrated by UV-vis spectroscopy measurements. The results revealed stronger toxic effects of Bio-AgNPs on agar plates what was confirmed clear inhibition zone around wells impregnated with Bio-AgNPs. On the other hand Bio-AgNPs were confirmed to be less toxic in aquatic environments for the growths of green algae P. kessleri comparing to Chem-AgNPs.

  2. Compaction of Chemically Prepared Amorphous Fe-B nanoparticles

    DEFF Research Database (Denmark)

    Hendriksen, P.V.; Bødker, Franz; Mørup, Steen

    1997-01-01

    We report on attempts to compact chemically prepared amorphous iron-boron particles. The praticles have a size of about 100 nm and are pyrophoric. We have made a special die for uniaxial pressing in which the compaction can be performed at elevated temperature without exposing the powder to air...

  3. Physico-chemical properties of Pd nanoparticles produced by Pulsed Laser Ablation in different organic solvents

    International Nuclear Information System (INIS)

    Cristoforetti, Gabriele; Pitzalis, Emanuela; Spiniello, Roberto; Ishak, Randa; Giammanco, Francesco; Muniz-Miranda, Maurizio; Caporali, Stefano

    2012-01-01

    Palladium nanoparticles are arousing an increasing interest because of their strong activity in heterogeneous catalysis in a wide range of reactions. Driven by the interest of producing Pd nanoparticles to be deposited for catalysis over hydrophobic supports, we investigated their synthesis via Pulsed Laser Ablation in Liquid in several organic solvents, as acetone, ethanol, 2-propanol, toluene, n-hexane. The colloids were produced by using a Nd:YAG ns laser and without the addition of surfactant agents. The morphology, composition, stability and oxidation state of the obtained nanoparticles were investigated by TEM-EDS analysis, UV-vis spectroscopy, X-ray Photoelectron Spectroscopy and micro-Raman spectroscopy. The results evidence that the nature of the solvent influences both the yield and the physico-chemical properties of the produced nanoparticles. While in acetone and alcohols spheroidal, non aggregated and stable particles are obtained, in case of toluene and n-hexane few unstable particles surrounded by a gel-like material are produced. Raman/XPS measurements suggest the presence of amorphous or graphitic carbon onto crystalline Pd nanoparticles, which could have hindered their growth and determined the observed smaller sizes if compared to nanoparticles produced in water. The stability of Pd colloids obtained in acetone and alcohols was attributed to adsorbed anions like enolates or alcoholates; non polar solvents like toluene and n-hexane, unable to give rise to adsorbed anionic species, cannot provide any stabilization to the palladium nanoparticles. XPS analyses also evidenced a partial oxidation of particles surface, with a ratio Pd 2+ :Pd 0 of 1:2.5 and 1:4 in acetone and ethanol, respectively.

  4. Nanoparticle-based optical biosensors for the direct detection of organophosphate chemical warfare agents and pesticides

    International Nuclear Information System (INIS)

    Simonian, A.L.; Good, T.A.; Wang, S.-S.; Wild, J.R.

    2005-01-01

    Neurotoxic organophosphates (OP) have found widespread use in the environment for insect control. In addition, there is the increasing threat of use of OP based chemical warfare agents in both ground based warfare and terrorist attacks. Together, these trends necessitate the development of simple and specific methods for discriminative detection of ultra low quantities of OP neurotoxins. In our previous investigations a new biosensor for the direct detection of organophosphorus neurotoxins was pioneered. In this system, the enzymatic hydrolysis of OP neurotoxins by organophosphate hydrolase (OPH) generated two protons in each hydrolytic turnover through reactions in which P-X bonds are cleaved. The sensitivity of this biosensor was limited due to the potentiometric method of detection. Recently, it was reported that a change in fluorescence properties of a fluorophore in the vicinity of gold nanoparticles might be used for detection of nanomolar concentrations of DNA oligonucleotides. The detection strategy was based on the fact that an enhancement or quenching of fluorescence intensity is a function of the distances between the gold nanoparticle and fluorophore. While these reports have demonstrated the use of nanoparticle-based sensors for the detection of target DNA, we observed that the specificity of enzyme-substrate interactions could be exploited in similar systems. To test the feasibility of this approach, OPH-gold nanoparticle conjugates were prepared, then incubated with a fluorescent enzyme inhibitor or decoy. The fluorescence intensity of the decoy was sensitive to the proximity of the gold nanoparticle, and thus could be used to indicate that the decoy was bound to the OPH. Then different paraoxon concentrations were introduced to the OPH-nanoparticle-conjugate-decoy mixtures, and normalized ratio of fluorescence intensities were measured. The greatest sensitivity to paraoxon was obtained when decoys and OPH-gold nanoparticle conjugates were present at

  5. Physical-Chemical Characterization and Formulation Considerations for Solid Lipid Nanoparticles.

    Science.gov (United States)

    Chauhan, Harsh; Mohapatra, Sarat; Munt, Daniel J; Chandratre, Shantanu; Dash, Alekha

    2016-06-01

    Pure glyceryl mono-oleate (GMO) (lipid) and different batches of GMO commonly used for the preparation of GMO-chitosan nanoparticles were characterized by modulated differential scanning calorimetry (MDSC), cryo-microscopy, and cryo-X-ray powder diffraction techniques. GMO-chitosan nanoparticles containing poloxamer 407 as a stabilizer in the absence and presence of polymers as crystallization inhibitors were prepared by ultrasonication. The effect of polymers (polyvinyl pyrrolidone (PVP), Eudragits, hydroxyl propyl methyl cellulose (HPMC), polyethylene glycol (PEG)), surfactants (poloxamer), and oils (mineral oil and olive oil) on the crystallization of GMO was investigated. GMO showed an exothermic peak at around -10°C while cooling and another exothermic peak at around -12°C while heating. It was followed by two endothermic peaks between 15 and 30 C, indicative of GMO melting. The results are corroborated by cryo-microscopy and cryo-X-ray. Significant differences in exothermic and endothermic transition were observed between different grades of GMO and pure GMO. GMO-chitosan nanoparticles resulted in a significant increase in particle size after lyophilization. MDSC confirmed that nanoparticles showed similar exothermic crystallization behavior of lipid GMO. MDSC experiments showed that PVP inhibits GMO crystallization and addition of PVP showed no significant increase in particle size of solid lipid nanoparticle (SLN) during lyophilization. The research highlights the importance of extensive physical-chemical characterization for successful formulation of SLN.

  6. Synthesis and Characterization of Cadmium Sulfide Nanoparticles by Chemical Precipitation Method.

    Science.gov (United States)

    Devi, R Aruna; Latha, M; Velumani, S; Oza, Goldie; Reyes-Figueroa, P; Rohini, M; Becerril-Juarez, I G; Lee, Jae-Hyeong; Yi, Junsin

    2015-11-01

    Cadmium sulfide (CdS) nanoparticles were synthesized by chemical precipitation method using cadmium chloride (CdCl2), sodium sulfide (Na2S) and water as a solvent by varying temperatures from 20-80 degrees C. The nanoparticles were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), High-resolution transmission electron microscopy (HR-TEM) and UV-Visible spectroscopy. XRD pattern revealed cubic crystal structure for all the synthesized CdS nanoparticles. Raman spectra showed first and second order longitudinal optical (LO) phonon vibrational modes of CdS. The size of CdS nanoparticles was found to be in the range of 15-80 nm by FE-SEM analysis, in all cases. The atomic percentage of cadmium and sulfur was confirmed to be 1:1 from EDS analysis. TEM micrograph depicts the spherical shape of the particles and the size is in the range of 15-85 nm while HR-TEM images of CdS nanoparticles exhibit well-resolved lattice fringes of the cubic structure of CdS. The optical properties of CdS were examined by UV-Visible spectroscopy which showed variation in absorption band from 460-480 nm. The band gap was calculated from the absorption edge and found to be in the range of 3.2-3.5 eV which is greater than the bulk CdS.

  7. Effects of organic solvents on hyaluronic acid nanoparticles obtained by precipitation and chemical crosslinking.

    Science.gov (United States)

    Bicudo, Rafaela Costa Souza; Santana, Maria Helena Andrade

    2012-03-01

    Hyaluronic acid is a hydrophilic mucopolysaccharide composed of alternating units of D-glucuronic acid and N-acetylglucosamine. It is used in many medical, pharmaceutical, and cosmetic applications, as sponges, films, or particle formulations. Hyaluronic acid nanoparticles can be synthesized free of oil and surfactants by nanoprecipitation in organic solvents, followed by chemical crosslinking. The organic solvent plays an important role in particles size and structure. Therefore, this study aimed to investigate the influence of acetone, ethanol, and isopropyl alcohol on the synthesis and physico-chemical properties of hyaluronic acid nanoparticles. Particles were crosslinked with adipic hydrazide and chloride carbodiimide under controlled conditions. The nanoparticles obtained with all three studied solvents were moderately electrostatically stable. Experiments with acetone produced the smallest particle size (120.44 nm) and polydispersity (0.27). The size and polydispersity of hyaluronic acid nanoparticles correlated with the surface tension between water and the organic solvents, not with the thermodynamic affinity of water for the organic solvents.

  8. The Synthesis of Silver Nanoparticles Produced by Chemical Reduction of Silver Salt Solution

    International Nuclear Information System (INIS)

    Sri Budi Harmani; Dewi Sondari; Agus Haryono

    2008-01-01

    Described in this research are the synthesis of silver nanoparticle produced by chemical reduction of silver salt (silver nitrate AgNO 3 ) solution. As a reducer, sodium citrate (C 6 H 5 O 7 Na 3 ) was used. Preparation of silver colloid is done by using chemical reduction method. In typical experiment 150 ml of 1.10 -3 M AgNO 3 solution was heated with temperature variation such as 90, 100, 110 degree of Celsius. To this solution 15 ml of 1 % trisodium citrate was added into solution drop by drop during heating. During the process, solution was mixed vigorously. Solution was heated until colour's change is evident (pale yellow solution is formed). Then it was removed from the heating element and stirred until cooled to room temperature. Experimental result showed that diameter of silver nanoparticles in colloid solution is about 28.3 nm (Ag colloid, 90 o C); 19.9 nm (Ag colloid, 100 o C)and 26.4 nm (Ag colloid, 110 o C). Characterization of the silver nanoparticle colloid conducted by using UV-Vis Spectroscopy, Particles Size Analyzer (PSA) and Scanning Electron Microscope (SEM) indicate the produced structures of silver nanoparticles. (author)

  9. The impact of the chemical synthesis on the magnetic properties of intermetallic PdFe nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos-Rubio, I.; Insausti, M.; Muro, I. Gil de [Universidad del País Vasco, UPV/EHU, Dpto. de Química Inorgánica (Spain); Arias-Duque, D. Carolina; Hernández-Garrido, Juan Carlos [Universidad de Cadiz, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias (Spain); Rojo, T.; Lezama, L., E-mail: luis.lezama@ehu.es [Universidad del País Vasco, UPV/EHU, Dpto. de Química Inorgánica (Spain)

    2015-05-15

    Palladium-rich Iron nanoparticles in the 4–8 nm range have been produced by a combination of two methods: the thermal decomposition of organometallic precursors and the reduction of metallic salts by a polyol. Herein, it is shown how the details of the synthesis have a striking impact on the magnetic and morphological properties of the final products. In the synthesis of these bimetallic nanoparticles, the use of high reaction temperatures plays an essential role in attaining good chemical homogeneity, which has proved to have a key influence on the magnetic properties. Magnetic characterization has been performed by electron magnetic resonance and magnetization measurements, which have confirmed the superparamagnetic-like behavior at room temperature. No clear traces of magnetic polarization in palladium atoms have been detected. The combination of long-term stability and homogeneous chemical and magnetic properties makes these particles very suitable for a wide range of applications in nanotechnology.

  10. The impact of the chemical synthesis on the magnetic properties of intermetallic PdFe nanoparticles

    International Nuclear Information System (INIS)

    Castellanos-Rubio, I.; Insausti, M.; Muro, I. Gil de; Arias-Duque, D. Carolina; Hernández-Garrido, Juan Carlos; Rojo, T.; Lezama, L.

    2015-01-01

    Palladium-rich Iron nanoparticles in the 4–8 nm range have been produced by a combination of two methods: the thermal decomposition of organometallic precursors and the reduction of metallic salts by a polyol. Herein, it is shown how the details of the synthesis have a striking impact on the magnetic and morphological properties of the final products. In the synthesis of these bimetallic nanoparticles, the use of high reaction temperatures plays an essential role in attaining good chemical homogeneity, which has proved to have a key influence on the magnetic properties. Magnetic characterization has been performed by electron magnetic resonance and magnetization measurements, which have confirmed the superparamagnetic-like behavior at room temperature. No clear traces of magnetic polarization in palladium atoms have been detected. The combination of long-term stability and homogeneous chemical and magnetic properties makes these particles very suitable for a wide range of applications in nanotechnology

  11. Chemical and structural properties of Pd nanoparticle-decorated graphene-Electron spectroscopic methods and QUASES

    Czech Academy of Sciences Publication Activity Database

    Lesiak, B.; Jiříček, Petr; Bieloshapka, Igor

    2017-01-01

    Roč. 404, May (2017), s. 300-309 ISSN 0169-4332 R&D Projects: GA MŠk LM2015088 Institutional support: RVO:68378271 Keywords : graphite (Gr) * graphene oxide (GO) * reduced graphene oxide (RGO) * Pd nanoparticles * XPS * QUASES * REELS * chemical and structural properties Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.387, year: 2016

  12. Developing a predictive model for the chemical composition of soot nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Violi, Angela [Univ. of Michigan, Ann Arbor, MI (United States); Michelsen, Hope [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Hansen, Nils [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Wilson, Kevin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-04-07

    In order to provide the scientific foundation to enable technology breakthroughs in transportation fuel, it is important to develop a combustion modeling capability to optimize the operation and design of evolving fuels in advanced engines for transportation applications. The goal of this proposal is to develop a validated predictive model to describe the chemical composition of soot nanoparticles in premixed and diffusion flames. Atomistic studies in conjunction with state-of-the-art experiments are the distinguishing characteristics of this unique interdisciplinary effort. The modeling effort has been conducted at the University of Michigan by Prof. A. Violi. The experimental work has entailed a series of studies using different techniques to analyze gas-phase soot precursor chemistry and soot particle production in premixed and diffusion flames. Measurements have provided spatial distributions of polycyclic aromatic hydrocarbons and other gas-phase species and size and composition of incipient soot nanoparticles for comparison with model results. The experimental team includes Dr. N. Hansen and H. Michelsen at Sandia National Labs' Combustion Research Facility, and Dr. K. Wilson as collaborator at Lawrence Berkeley National Lab's Advanced Light Source. Our results show that the chemical and physical properties of nanoparticles affect the coagulation behavior in soot formation, and our results on an experimentally validated, predictive model for the chemical composition of soot nanoparticles will not only enhance our understanding of soot formation since but will also allow the prediction of particle size distributions under combustion conditions. These results provide a novel description of soot formation based on physical and chemical properties of the particles for use in the next generation of soot models and an enhanced capability for facilitating the design of alternative fuels and the engines they will power.

  13. Chemical composition dispersion in bi-metallic nanoparticles: semi-automated analysis using HAADF-STEM

    International Nuclear Information System (INIS)

    Epicier, T.; Sato, K.; Tournus, F.; Konno, T.

    2012-01-01

    We present a method using high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) to determine the chemical composition of bi-metallic nanoparticles. This method, which can be applied in a semi-automated way, allows large scale analysis with a statistical number of particles (several hundreds) in a short time. Once a calibration curve has been obtained, e.g., using energy-dispersive X-ray spectroscopy (EDX) measurements on a few particles, the HAADF integrated intensity of each particle can indeed be directly related to its chemical composition. After a theoretical description, this approach is applied to the case of iron–palladium nanoparticles (expected to be nearly stoichiometric) with a mean size of 8.3 nm. It will be shown that an accurate chemical composition histogram is obtained, i.e., the Fe content has been determined to be 49.0 at.% with a dispersion of 10.4 %. HAADF-STEM analysis represents a powerful alternative to fastidious single particle EDX measurements, for the compositional dispersion in alloy nanoparticles.

  14. SiO{sub 2} coating of silver nanoparticles by photoinduced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Boies, Adam M; Girshick, Steven L [Department of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, MN 55455 (United States); Roberts, Jeffrey T [Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455 (United States); Zhang Bin; Nakamura, Toshitaka; Mochizuki, Amane, E-mail: jtrob@umn.ed, E-mail: slg@umn.ed [Nitto Denko Technical Corporation, 501 Via Del Monte, Oceanside, CA 92058 (United States)

    2009-07-22

    Gas-phase silver nanoparticles were coated with silicon dioxide (SiO{sub 2}) by photoinduced chemical vapor deposition (photo-CVD). Silver nanoparticles, produced by inert gas condensation, and a SiO{sub 2} precursor, tetraethylorthosilicate (TEOS), were exposed to vacuum ultraviolet (VUV) radiation at atmospheric pressure and varying temperatures. The VUV photons dissociate the TEOS precursor, initiating a chemical reaction that forms SiO{sub 2} coatings on the particle surfaces. Coating thicknesses were measured for a variety of operation parameters using tandem differential mobility analysis and transmission electron microscopy. The chemical composition of the particle coatings was analyzed using energy dispersive x-ray spectrometry and Fourier transform infrared spectroscopy. The highest purity films were produced at 300-400 {sup 0}C with low flow rates of additional oxygen. The photo-CVD coating technique was shown to effectively coat nanoparticles and limit core particle agglomeration at concentrations up to 10{sup 7} particles cm{sup -3}.

  15. [Wet work].

    Science.gov (United States)

    Kieć-Swierczyńska, Marta; Chomiczewska, Dorota; Krecisz, Beata

    2010-01-01

    Wet work is one of the most important risk factors of occupational skin diseases. Exposure of hands to the wet environment for more than 2 hours daily, wearing moisture-proof protective gloves for a corresponding period of time or necessity to wash hands frequently lead to the disruption of epidermal stratum corneum, damage to skin barrier function and induction of irritant contact dermatitis. It may also promote penetration of allergens into the skin and increase the risk of sensitization to occupational allergens. Exposure to wet work plays a significant role in occupations, such as hairdressers and barbers, nurses and other health care workers, cleaning staff, food handlers and metalworkers. It is more common among women because many occupations involving wet work are female-dominated. The incidence of wet-work-induced occupational skin diseases can be reduced by taking appropriate preventive measures. These include identification of high-risk groups, education of workers, organization of work enabling to minimize the exposure to wet work, use of personal protective equipment and skin care after work.

  16. Synthesis, characterization and catalytic performance of ZnO-CeO2 nanoparticles in wet oxidation of wastewater containing chlorinated compounds

    Science.gov (United States)

    Anushree; Kumar, S.; Sharma, C.

    2017-11-01

    Here we report the catalytic property of ZnO-CeO2 nanoparticles towards oxidative degradation of organic pollutants present in industrial wastewater. The catalysts were prepared by co-precipitation method without using any surfactant. The physicochemical properties of catalysts were studied by XRD, Raman, XPS, N2-sorption, FE-SEM, TEM and EDX techniques. The characterization results confirmed the formation of porous ZnO-CeO2 nanocatalysts with high surface area, pore volume and oxygen vacancies. ZnO-CeO2 nanocatalysts exhibited appreciable efficiency in CWAO of industrial wastewater under mild conditions. The Ce40Zn60 catalyst was found to be most efficient with 72% color, 64% chemical oxygen demand (COD) and 63% total organic carbon (TOC) removal. Efficient removal of chlorophenolics (CHPs, 59%) and adsorbable organic halides (AOX, 54%) indicated the feasibility of using ZnO-CeO2 nanocatalysts in degradation of non-biodegradable and toxic chlorinated compounds.

  17. PREFACE: Dynamics of wetting Dynamics of wetting

    Science.gov (United States)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

    2009-11-01

    Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting

  18. Investigation of discharged aerosol nanoparticles during chemical precipitation and spray pyrolysis for developing safety measures in the nano research laboratory.

    Science.gov (United States)

    Kolesnikov, Еvgeny; Karunakaran, Gopalu; Godymchuk, Anna; Vera, Levina; Yudin, Andrey Grigorjevich; Gusev, Alexander; Kuznetsov, Denis

    2017-05-01

    Nowadays, the demands for the nanoparticles are increasing due to their tremendous applications in various fields. As a consequence, the discharge of nanoparticles into the atmosphere and environment is also increasing, posing a health threat and environmental damage in terms of pollution. Thus, an extensive research is essential to evaluate the discharge of these nanoparticles into the environment. Keeping this in mind, the present investigation aimed to analyze the discharge of aerosol nanoparticles that are synthesized in the laboratory via chemical precipitation and spray pyrolysis methods. The results indicated that the chemical precipitation method discharges a higher concentration of nanoparticles in the work site when compared to the spray pyrolysis method. The aerosol concentration also varied with the different steps involved during the synthesis of nanoparticles. The average particle's concentration in air for chemical precipitation and spray pyrolysis methods was around 1,037,476 and 883,421particles/cm 3 . In addition, the average total discharge of nanoparticles in the entire laboratory was also examined. A significant variation in the concentration of nanoparticles was noticed, during the processing of materials and the concentration of particles (14-723nm) exceeding the daily allowed concentration to about 70-170 times was observed over a period of 6 months. Thus, the results of the present study will be very useful in developing safety measures and would help in organizing the rules for people working in nanotechnology laboratories to minimize the hazardous effects. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Optimization and characterization of high pressure homogenization produced chemically modified starch nanoparticles.

    Science.gov (United States)

    Ding, Yongbo; Kan, Jianquan

    2017-12-01

    Chemically modified starch (RS4) nanoparticles were synthesized through homogenization and water-in-oil mini-emulsion cross-linking. Homogenization was optimized with regard to z-average diameter by using a three-factor-three-level Box-Behnken design. Homogenization pressure (X 1 ), oil/water ratio (X 2 ), and surfactant (X 3 ) were selected as independent variables, whereas z-average diameter was considered as a dependent variable. The following optimum preparation conditions were obtained to achieve the minimum average size of these nanoparticles: 50 MPa homogenization pressure, 10:1 oil/water ratio, and 2 g surfactant amount, when the predicted z-average diameter was 303.6 nm. The physicochemical properties of these nanoparticles were also determined. Dynamic light scattering experiments revealed that RS4 nanoparticles measuring a PdI of 0.380 and an average size of approximately 300 nm, which was very close to the predicted z-average diameter (303.6 nm). The absolute value of zeta potential of RS4 nanoparticles (39.7 mV) was higher than RS4 (32.4 mV), with strengthened swelling power. X-ray diffraction results revealed that homogenization induced a disruption in crystalline structure of RS4 nanoparticles led to amorphous or low-crystallinity. Results of stability analysis showed that RS4 nanosuspensions (particle size) had good stability at 30 °C over 24 h.

  20. Random telegraph signals by alkanethiol-protected Au nanoparticles in chemically assembled single-electron transistors

    International Nuclear Information System (INIS)

    Kano, Shinya; Azuma, Yasuo; Tanaka, Daisuke; Sakamoto, Masanori; Teranishi, Toshiharu; Smith, Luke W.; Smith, Charles G.; Majima, Yutaka

    2013-01-01

    We have studied random telegraph signals (RTSs) in a chemically assembled single-electron transistor (SET) at temperatures as low as 300 mK. The RTSs in the chemically assembled SET were investigated by measuring the source–drain current, using a histogram of the RTS dwell time, and calculating the power spectrum density of the drain current–time characteristics. It was found that the dwell time of the RTS was dependent on the drain voltage of the SET, but was independent of the gate voltage. Considering the spatial structure of the chemically assembled SET, the origin of the RTS is attributed to the trapped charges on an alkanethiol-protected Au nanoparticle positioned near the SET. These results are important as they will help to realize stable chemically assembled SETs in practical applications

  1. Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

    Science.gov (United States)

    Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

    2004-01-01

    Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste

  2. Synthesis and characterization of CoPt nanoparticles prepared by room temperature chemical reduction with PAMAM dendrimer as template.

    Science.gov (United States)

    Wan, Haiying; Shi, Shifan; Bai, Litao; Shamsuzzoha, Mohammad; Harrell, J W; Street, Shane C

    2010-08-01

    We describe an approach to synthesize monodisperse CoPt nanoparticles with dendrimer as template by a simple chemical reduction method in aqueous solution using NaBH4 as reducing agent at room temperature. The as-made CoPt nanoparticles buried in the dendrimer matrix have the chemically disordered fcc structure and can be transformed to the fct phase after annealing at 700 degrees C. This is the first report of dendrimer-mediated room temperature synthesis of monodisperse magnetic nanoparticles in aqueous solution.

  3. Wet-Chemical Preparation of TiO2-Based Composites with Different Morphologies and Photocatalytic Properties

    Directory of Open Access Journals (Sweden)

    Liqin Xiang

    2017-10-01

    Full Text Available TiO2-based composites have been paid significant attention in the photocatalysis field. The size, crystallinity and nanomorphology of TiO2 materials have an important effect on the photocatalytic efficiency. The synthesis and photocatalytic activity of TiO2-based materials have been widely investigated in past decades. Based on our group’s research works on TiO2 materials, this review introduces several methods for the fabrication of TiO2, rare-earth-doped TiO2 and noble-metal-decorated TiO2 particles with different morphologies. We focused on the preparation and the formation mechanism of TiO2-based materials with unique structures including spheres, hollow spheres, porous spheres, hollow porous spheres and urchin-like spheres. The photocatalytical activity of urchin-like TiO2, noble metal nanoparticle-decorated 3D (three-dimensional urchin-like TiO2 and bimetallic core/shell nanoparticle-decorated urchin-like hierarchical TiO2 are briefly discussed.

  4. Synthesis and characterization of magnetite nanoparticles via the chemical co-precipitation method

    International Nuclear Information System (INIS)

    Petcharoen, K.; Sirivat, A.

    2012-01-01

    Highlights: ► Size-controlled magnetite nanoparticles were prepared via the chemical co-precipitation method in the range of 10–40 nm. ► The electrical conductivity of the smallest particle size is 1.3 × 10 −3 S/cm which belongs to the semiconductor material group. ► The surface modification of magnetite nanoparticles can provide the suspension stability over 1 week. - Abstract: Magnetite nanoparticles were synthesized via the chemical co-precipitation method using ammonium hydroxide as the precipitating agent. The size of the magnetite nanoparticles was carefully controlled by varying the reaction temperature and through the surface modification. Herein, the hexanoic acid and oleic acid were introduced as the coating agents during the initial crystallization phase of the magnetite. Their structure and morphology were characterized by the Fourier transform infrared spectroscopy (FTIR), the X-ray diffraction (XRD) and the field-emission scanning electron microscopy (FE-SEM). Moreover, the electrical and magnetic properties were studied by using a conductivity meter and a vibrating sample magnetometer (VSM), respectively. Both of the bare magnetite and the coated magnetite were of the cubic spinel structure and the spherical-shaped morphology. The reaction temperature and the surface modification critically affected the particle size, the electrical conductivity, and the magnetic properties of these particles. The particle size of the magnetite was increased through the surface modification and reaction temperature. In this study, the particle size of the magnetite nanoparticles was successfully controlled to be in the range of 10–40 nm, suitable for various biomedical applications. The electrical conductivity of the smallest particle size was 1.3 × 10 −3 S/cm, within the semi-conductive materials range, which was higher than that of the largest particle by about 5 times. All of the magnetite nanoparticles showed the superparamagnetic behavior with

  5. A chemical approach to accurately characterize the coverage rate of gold nanoparticles

    International Nuclear Information System (INIS)

    Zhu, Xiaoli; Liu, Min; Zhang, Huihui; Wang, Haiyan; Li, Genxi

    2013-01-01

    Gold nanoparticles (AuNPs) have been widely used in many areas, and the nanoparticles usually have to be functionalized with some molecules before use. However, the information about the characterization of the functionalization of the nanoparticles is still limited or unclear, which has greatly restricted the better functionalization and application of AuNPs. Here, we propose a chemical way to accurately characterize the functionalization of AuNPs. Unlike the traditional physical methods, this method, which is based on the catalytic property of AuNPs, may give accurate coverage rate and some derivative information about the functionalization of the nanoparticles with different kinds of molecules. The performance of the characterization has been approved by adopting three independent molecules to functionalize AuNPs, including both covalent and non-covalent functionalization. Some interesting results are thereby obtained, and some are the first time to be revealed. The method may also be further developed as a useful tool for the characterization of a solid surface

  6. Characteristics of Barium Hexaferrite Nanoparticles Prepared by Temperature-Controlled Chemical Coprecipitation

    International Nuclear Information System (INIS)

    Kwak, Jun Young; Lee, Choong Sub; Kim, Don; Kim, Yeong Il

    2012-01-01

    Ba-ferrite (BaFe 12 O 19 ) nanoparticles were synthesized by chemical coprecipitation method in an aqueous solution. The particle size and the crystallization temperature of the Ba-ferrite nanoparticles were controlled varying the precipitation temperature. The precipitate that was prepared at 0 .deg. C showed the crystal structure of Ba-ferrite in X-ray diffraction when it was calcined at the temperature above 580 .deg. C, whereas what was prepared at 50 .deg. C showed the crystallinity when it was calcined at the temperature higher than about 700 .deg. C. The particle sizes of the synthesized Ba-ferrite were in a range of about 20-30 nm when it was prepared by being precipitated at 0 .deg. C and calcined at 650 .deg. C. When the precipitation temperature increased, the particle size also increased even at the same calcination temperature. The magnetic properties of the Ba-ferrite nanoparticles were also controlled by the synthetic condition of precipitation and calcination temperature. The coercive force could be appreciably lowered without a loss of saturation magnetization when the Ba-ferrite nanoparticles were prepared by precipitation and calcination both at low temperatures

  7. A chemical approach to accurately characterize the coverage rate of gold nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaoli; Liu, Min; Zhang, Huihui [Shanghai University, Laboratory of Biosensing Technology, School of Life Sciences (China); Wang, Haiyan [Nanjing University, State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry (China); Li, Genxi, E-mail: genxili@nju.edu.cn [Shanghai University, Laboratory of Biosensing Technology, School of Life Sciences (China)

    2013-09-15

    Gold nanoparticles (AuNPs) have been widely used in many areas, and the nanoparticles usually have to be functionalized with some molecules before use. However, the information about the characterization of the functionalization of the nanoparticles is still limited or unclear, which has greatly restricted the better functionalization and application of AuNPs. Here, we propose a chemical way to accurately characterize the functionalization of AuNPs. Unlike the traditional physical methods, this method, which is based on the catalytic property of AuNPs, may give accurate coverage rate and some derivative information about the functionalization of the nanoparticles with different kinds of molecules. The performance of the characterization has been approved by adopting three independent molecules to functionalize AuNPs, including both covalent and non-covalent functionalization. Some interesting results are thereby obtained, and some are the first time to be revealed. The method may also be further developed as a useful tool for the characterization of a solid surface.

  8. Titanium dioxide nanoparticles: synthesis, X-Ray line analysis and chemical composition study

    Energy Technology Data Exchange (ETDEWEB)

    Chenari, Hossein Mahmoudi, E-mail: mahmoudi_hossein@guilan.ac.ir, E-mail: h.mahmoudiph@gmail.com [University of Guilan, Rasht (Iran, Islamic Republic of); Seibel, Christoph; Hauschild, Dirk; Reinert, Friedrich [Karlsruhe Institute of Technology - KIT, Gemeinschaftslabor für Nanoanalytik, Karlsruhe (Germany); Abdollahian, Hossein [Nanotechnology Research Center of Urmia University, Urmia, (Iran, Islamic Republic of)

    2016-11-15

    TiO{sub 2} nanoparticles have been synthesized by the sol-gel method using titanium alkoxide and isopropanol as a precursor. The structural properties and chemical composition of the TiO{sub 2} nanoparticles were studied using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy.The X-ray powder diffraction pattern confirms that the particles are mainly composed of the anatase phase with the preferential orientation along [101] direction. The physical parameters such as strain, stress and energy density were investigated from the Williamson- Hall (W-H) plot assuming a uniform deformation model (UDM), and uniform deformation energy density model (UDEDM). The W-H analysis shows an anisotropic nature of the strain in nano powders. The scanning electron microscopy image shows clear TiO{sub 2} nanoparticles with particle sizes varying from 60 to 80nm. The results of mean particle size of TiO{sub 2} nanoparticles show an inter correlation with the W-H analysis and SEM results. Our X-ray photoelectron spectroscopy spectra show that nearly a complete amount of titanium has reacted to TiO{sub 2}. (author)

  9. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes

    Energy Technology Data Exchange (ETDEWEB)

    Swain, Basudev, E-mail: swain@iae.re.kr [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of); Mishra, Chinmayee [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of); Hong, Hyun Seon [Sungshin University, Dept. of Interdisciplinary ECO Science, Seoul, 142-732 (Korea, Republic of); Cho, Sung-Soo [Institute for Advanced Engineering, Advanced Materials & Processing Center, Yongin, 449-863 (Korea, Republic of)

    2016-05-15

    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m{sup 3} of copper and 1.35 kg/m{sup 3} of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100–500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. - Highlights: • From the Indium-Tin-Oxide etching

  10. Selective recovery of pure copper nanopowder from indium-tin-oxide etching wastewater by various wet chemical reduction process: Understanding their chemistry and comparisons of sustainable valorization processes

    International Nuclear Information System (INIS)

    Swain, Basudev; Mishra, Chinmayee; Hong, Hyun Seon; Cho, Sung-Soo

    2016-01-01

    Sustainable valorization processes for selective recovery of pure copper nanopowder from Indium-Tin-Oxide (ITO) etching wastewater by various wet chemical reduction processes, their chemistry has been investigated and compared. After the indium recovery by solvent extraction from ITO etching wastewater, the same is also an environmental challenge, needs to be treated before disposal. After the indium recovery, ITO etching wastewater contains 6.11 kg/m 3 of copper and 1.35 kg/m 3 of aluminum, pH of the solution is very low converging to 0 and contain a significant amount of chlorine in the media. In this study, pure copper nanopowder was recovered using various reducing reagents by wet chemical reduction and characterized. Different reducing agents like a metallic, an inorganic acid and an organic acid were used to understand reduction behavior of copper in the presence of aluminum in a strong chloride medium of the ITO etching wastewater. The effect of a polymer surfactant Polyvinylpyrrolidone (PVP), which was included to prevent aggregation, to provide dispersion stability and control the size of copper nanopowder was investigated and compared. The developed copper nanopowder recovery techniques are techno-economical feasible processes for commercial production of copper nanopowder in the range of 100–500 nm size from the reported facilities through a one-pot synthesis. By all the process reported pure copper nanopowder can be recovered with>99% efficiency. After the copper recovery, copper concentration in the wastewater reduced to acceptable limit recommended by WHO for wastewater disposal. The process is not only beneficial for recycling of copper, but also helps to address environment challenged posed by ITO etching wastewater. From a complex wastewater, synthesis of pure copper nanopowder using various wet chemical reduction route and their comparison is the novelty of this recovery process. - Highlights: • From the Indium-Tin-Oxide etching wastewater

  11. Local Chemical Ordering and Negative Thermal Expansion in PtNi Alloy Nanoparticles.

    Science.gov (United States)

    Li, Qiang; Zhu, He; Zheng, Lirong; Fan, Longlong; Wang, Na; Rong, Yangchun; Ren, Yang; Chen, Jun; Deng, Jinxia; Xing, Xianran

    2017-12-13

    An atomic insight into the local chemical ordering and lattice strain is particular interesting to recent emerging bimetallic nanocatalysts such as PtNi alloys. Here, we reported the atomic distribution, chemical environment, and lattice thermal evolution in full-scale structural description of PtNi alloy nanoparticles (NPs). The different segregation of elements in the well-faceted PtNi nanoparticles is convinced by extended X-ray absorption fine structure (EXAFS). Atomic pair distribution function (PDF) study evidences the coexistence of the face-centered cubic and tetragonal ordering parts in the local environment of PtNi nanoparticles. Further reverse Monte Carlo (RMC) simulation with PDF data obviously exposed the segregation as Ni and Pt in the centers of {111} and {001} facets, respectively. Layer-by-layer statistical analysis up to 6 nm for the local atomic pairs revealed the distribution of local tetragonal ordering on the surface. This local coordination environment facilitates the distribution of heteroatomic Pt-Ni pairs, which plays an important role in the negative thermal expansion of Pt 41 Ni 59 NPs. The present study on PtNi alloy NPs from local short-range coordination to long-range average lattice provides a new perspective on tailoring physical properties in nanomaterials.

  12. Wet-Chemical Synthesis of Enhanced-Thermopower Bi1 -xSbx Nanowire Composites for Solid-State Active Cooling of Electronics

    Science.gov (United States)

    Vandaele, K.; He, Bin; Van Der Voort, P.; De Buysser, K.; Heremans, J. P.

    2018-02-01

    This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. In 1993, Hicks and Dresselhaus [Thermoelectric figure of merit of a one-dimensional conductor, Phys. Rev. B 47, 16631 (1993)., 10.1103/PhysRevB.47.16631] suggested that Bi nanowires could result in values of the thermoelectric figure of merit z T >1 . The Dresselhaus group also calculated a ternary phase diagram for Bi1 -xSbx nanowires as a function of x and wire diameter. This manuscript reports a wet-chemical method to synthesize Bi1 -xSbx -silica nanowire composites. Resistivity, Hall electron concentration, electron mobility, Seebeck and Nernst coefficients, and thermal conductivity of composites are measured and compared to bulk polycrystalline Bi1 -xSbx samples prepared either by ingot casting or by the same wet chemistry but without nanostructuring. A clear increase of the thermopower in 20-nm Bi94Sb6 -silica is reported when compared to bulk samples, and the values are among the highest found in the literature from 300 to 380 K, even though the electron concentration is higher than in the bulk. This suggests that consistent with theory, size quantization is responsible for the thermopower increase.

  13. SAFETY STUDIES TO MEASURE EXOTHERMIC REACTIONS OF SPENT PLUTONIUM DECONTAMINATION CHEMICALS USING WET AND DRY DECONTAMINATION METHODS

    International Nuclear Information System (INIS)

    HOPKINS, A.M.; JACKSON, G.W.; MINETTE, M.; EWALT, J.; COOPER, T.; SCOTT, P.; JONES, S.; SCHEELEY, R.

    2005-01-01

    The Plutonium Finishing Plant (PFP) at the Hanford site in Eastern Washington is currently being decommissioned by Fluor Hanford. Chemicals being considered for dccontamination of gloveboxes in PFP include cerium (IV) nitrate in a nitric acid solution, and proprietary commercial solutions that include acids and sequestering agents. Aggressive chemicals are commonly used to remove transuranic contaminants from process equipment to allow disposal of the equipment as low level waste. Fluor's decontamination procedure involves application of chemical solutions as a spray on the contaminated surfaces, followed by a wipe-down with rags. Alternatively, a process of applying oxidizing Ce IV ions contained in a gel matrix and vacuuming a dry gel material is being evaluated. These processes effectively transfer the transuranic materials to rags or a gel matrix which is then packaged as TRU waste and disposed

  14. Wet chemical synthesis of nickel supported on alumina catalysts; Sintese de catalisadores de niquel suportado em alumina por via umida

    Energy Technology Data Exchange (ETDEWEB)

    Freire, Ranny Rodrigues; Costa, Talita Kenya Oliveira; Morais, Ana Carla da Fonseca Ferreira; Costa, Ana Cristina Figueiredo de Melo; Freitas, Normanda Lino de, E-mail: normanda@ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2016-07-01

    Heterogenic catalysts are those found to be in a different phase on the reaction when compared to the reactants and products. Preferred when compared to homogeneous catalysts due to the easiness on which the separation is processed. The objective of this study is to obtain and characterize Alumina based catalysts impregnated with Nickel (Al{sub 2}O{sub 3}), by wet impregnation. The alumina was synthesized by combustion reaction. Before and after the impregnation the catalysts were characterized by X-ray diffraction (XRD), granulometric analysis, the textural analysis will be held by nitrogen adsorption (BET), energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The results show a presence of a stable crystalline phase of Al2O3 in all the studied samples and after the impregnation the second phase formed was of NiO and NiAl{sub 2}O{sub 4}. The Al{sub 2}O{sub 3} e Ni/Al{sub 2}O{sub 3} catalysts resulted in clusters with a medium diameter of 18.9 and 14.2 μm, respectively. The catalysts show a medium-pore characteristic (medium pore diameter between 2 and 50 nm), the superficial area to Al{sub 2}O{sub 3} and Ni/Al{sub 2}O{sub 3} catalysts were 8.69 m{sup 2}/g and 5.56 m{sup 2}/g, respectively. (author)

  15. Influence of copper nanoparticles on the physical-chemical properties of activated sludge.

    Directory of Open Access Journals (Sweden)

    Hong Chen

    Full Text Available The physical-chemical properties of activated sludge, such as flocculating ability, hydrophobicity, surface charge, settleability, dewaterability and bacteria extracellular polymer substances (EPS, play vital roles in the normal operation of wastewater treatment plants (WWTPs. The nanoparticles released from commercial products will enter WWTPs and can induce potential adverse effects on activated sludge. This paper focused on the effects of copper nanoparticles (CuNPs on these specific physical-chemical properties of activated sludge. It was found that most of these properties were unaffected by the exposure to lower CuNPs concentration (5 ppm, but different observation were made at higher CuNPs concentrations (30 and 50 ppm. At the higher CuNPs concentrations, the sludge surface charge increased and the hydrophobicity decreased, which were attributed to more Cu2+ ions released from the CuNPs. The carbohydrate content of EPS was enhanced to defense the toxicity of CuNPs. The flocculating ability was found to be deteriorated due to the increased cell surface charge, the decreased hydrophobicity, and the damaged cell membrane. The worsened flocculating ability made the sludge flocs more dispersed, which further increased the toxicity of the CuNPs by increasing the availability of the CuNPs to the bacteria present in the sludge. Further investigation indicated that the phosphorus removal efficiency decreased at higher CuNPs concentrations, which was consistent with the deteriorated physical-chemical properties of activated sludge. It seems that the physical-chemical properties can be used as an indicator for determining CuNPs toxicity to the bacteria in activated sludge. This work is important because bacteria toxicity effects to the activated sludge caused by nanoparticles may lead to the deteriorated treatment efficiency of wastewater treatment, and it is therefore necessary to find an easy way to indicate this toxicity.

  16. Role of the nanocrystallinity on the chemical ordering of Co(x)Pt(100-x) nanocrystals synthesized by wet chemistry.

    Science.gov (United States)

    Kameche, Farid; Ngo, Anh-Tu; Salzemann, Caroline; Cordeiro, Marco; Sutter, Eli; Petit, Christophe

    2015-11-14

    Co(x)Pt(100-x) nanoalloys have been synthesized by two different chemical processes either at high or at low temperature. Their physical properties and the order/disorder phase transition induced by annealing have been investigated depending on the route of synthesis. It is demonstrated that the chemical synthesis at high temperature allows stabilization of the fcc structure of the native nanoalloys while the soft chemical approach yields mainly poly or non crystalline structure. As a result the approach of the order/disorder phase transition is strongly modified as observed by high-resolution transmission electron microscopy (HR-TEM) studies performed during in situ annealing of the different nanoalloys. The control of the nanocrystallinity leads to significant decrease in the chemical ordering temperature as the ordered structure is observed at temperatures as low as 420 °C. This in turn preserves the individual nanocrystals and prevents their coalescence usually observed during the annealing necessary for the transition to an ordered phase.

  17. Synthesis of Coral-Like, Straw-Tied-Like, and Flower-Like Antimony Sulfides by a Facile Wet-Chemical Method

    Directory of Open Access Journals (Sweden)

    Jutarat Kavinchan

    2013-01-01

    Full Text Available Antimony sulfide (Sb2S3 was successfully synthesized from antimony chloride (SbCl3 and sodium thiosulfate pentahydrate (Na2S2O3·5H2O in ethylene glycol (EG without using any template by a facile wet-chemical method. X-ray diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM show that the products were orthorhombic Sb2S3 nanorods forming the coral-like, straw-tied-like, and flower-like architectures with the nanorods growing along the [001] direction. The energy gap (Eg was determined by UV-visible absorption to be 1.52 eV.

  18. Recovery of phosphorus and aluminium from sewage sludge ash by a new wet chemical elution process (SESAL-Phos-recovery process).

    Science.gov (United States)

    Petzet, S; Peplinski, B; Bodkhe, S Y; Cornel, P

    2011-01-01

    The potential of a new wet chemical process for phosphorus and aluminium recovery from sewage sludge ash by sequential elution with acidic and alkaline solutions has been investigated: SESAL-Phos (sequential elution of sewage sludge ash for aluminium and phosphorus recovery). Its most innovative aspect is an acidic pre-treatment step in which calcium is leached from the sewage sludge ash. Thus the percentage of alkaline soluble aluminium phosphates is increased from 20 to 67%. This aluminium phosphate is then dissolved in alkali. Subsequently, the dissolved phosphorus is precipitated as calcium phosphate with low heavy metal content and recovered from the alkaline solution. Dissolved aluminium is recovered and may be reused as a precipitant in wastewater treatment plants.

  19. Controllable Shrinking of Glass Capillary Nanopores Down to sub-10 nm by Wet-Chemical Silanization for Signal-Enhanced DNA Translocation.

    Science.gov (United States)

    Xu, Xiaolong; Li, Chuanping; Zhou, Ya; Jin, Yongdong

    2017-10-27

    Diameter is a major concern for nanopore based sensing. However, directly pulling glass capillary nanopore with diameter down to sub-10 nm is very difficult. So, post treatment is sometimes necessary. Herein, we demonstrate a facile and effective wet-chemical method to shrink the diameter of glass capillary nanopore from several tens of nanometers to sub-10 nm by disodium silicate hydrolysis. Its benefits for DNA translocation are investigated. The shrinking of glass capillary nanopore not only slows down DNA translocation, but also enhances DNA translocation signal and signal-to-noise ratio significantly (102.9 for 6.4 nm glass nanopore, superior than 15 for a 3 nm silicon nitride nanopore). It also affects DNA translocation behaviors, making the approach and glass capillary nanopore platform promising for DNA translocation studies.

  20. Toward intrinsic graphene surfaces: a systematic study on thermal annealing and wet-chemical treatment of SiO2-supported graphene devices.

    Science.gov (United States)

    Cheng, Zengguang; Zhou, Qiaoyu; Wang, Chenxuan; Li, Qiang; Wang, Chen; Fang, Ying

    2011-02-09

    By combining atomic force microscopy and trans-port measurements, we systematically investigated effects of thermal annealing on surface morphologies and electrical properties of single-layer graphene devices fabricated by electron beam lithography on silicon oxide (SiO(2)) substrates. Thermal treatment above 300 °C in vacuum was required to effectively remove resist residues on graphene surfaces. However, annealing at high temperature was found to concomitantly bring graphene in close contact with SiO(2) substrates and induce increased coupling between them, which leads to heavy hole doping and severe degradation of mobilities in graphene devices. To address this problem, a wet-chemical approach employing chloroform was developed in our study, which was shown to enable both intrinsic surfaces and enhanced electrical properties of graphene devices. Upon the recovery of intrinsic surfaces of graphene, the adsorption and assisted fibrillation of amyloid β-peptide (Aβ1-42) on graphene were electrically measured in real time.

  1. Physical, chemical and biological studies of gelatin/chitosan based transdermal fims with embedded silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Sneha Paul

    2015-12-01

    Full Text Available Objective: To study the physical, chemical and biological properties of composite chitosangelatin transdermal film along with silver nanoparticles as binding agent and determine the compatibility of the prepared amalgamation towards wound management. Methods: Transdermal film preparations were done by solvent casting method containing different concentrations of biological synthesized silver nanoparticles. The films were characterized by using scanning electron microscope for their morphology and the determination of silver metal was done by using inductively coupled plasma atomic emission spectroscopy. Then a quantity of silver nanoparticles was further proceeded by physiochemical parameters (weight, thickness, temperature, solubility, absorption, tensile strength, in vitro drug release and skin permeation and biological parameters studies (anti-microbial, cytotoxicity and reactive oxygen species. Results: The film prepared by utilizing 2 g of gelatin and 0.5 g of chitosan exhibited better results. The physiochemical parameters studies revealed higher concentration of silver nanoparticles would give better results. In vitro drug release studies through dialysis and skin permeation showed the release of drug versus time (h. These films had shown excellent inhibition against Streptococcus and Escherichia coli species. Cytotoxicity study by MTT indicated the mild toxicity existed as the concentration of silver nanoparticles increased. Reactive oxygen species generation studies of transdermal film by using 2'7'-dichlorofluorescein diacetate assay demonstrated that the fluorescent cells were found in the higher concentration, which indicated cell damage (reactive oxygen species generated. Conclusions: Based on these observations, in vitro performances against various characteristics of transdermal film, would be utilized as a distinct dressing material and patches accessible in market.

  2. Microfluidic Device for Controllable Chemical Release via Field-Actuated Membrane Incorporating Nanoparticles

    Directory of Open Access Journals (Sweden)

    Xiang Wang

    2013-01-01

    Full Text Available We report a robust magnetic-membrane-based microfluidic platform for controllable chemical release. The magnetic membrane was prepared by mixing polydimethylsiloxane (PDMS and carbonyl-iron nanoparticles together to obtain a flexible thin film. With combined, simultaneous regulation of magnetic stimulus and mechanical pumping, the desired chemical release rate can easily be realized. For example, the dose release experimental data was well fitted by a mathematical sigmoidal model, exhibiting a typical dose-response relationship, which shows promise in providing significant guidance for on-demand drug delivery. To test the platform’s feasibility, our microfluidic device was employed in an experiment involving Escherichia coli culture under controlled antibiotic ciprofloxacin exposure, and the expected outcomes were successfully obtained. Our experimental results indicate that such a microfluidic device, with high accuracy and easy manipulation properties, can legitimately be characterized as active chemical release system.

  3. Microfluidic Device for Controllable Chemical Release via Field-Actuated Membrane Incorporating Nanoparticles

    KAUST Repository

    Wang, Xiang; Li, Shunbo; Wang, Limu; Yi, Xin; Hui, Yu Sanna; Qin, Jianhua; Wen, Weijia

    2013-01-01

    We report a robust magnetic-membrane-based microfluidic platform for controllable chemical release. The magnetic membrane was prepared by mixing polydimethylsiloxane (PDMS) and carbonyl-iron nanoparticles together to obtain a flexible thin film. With combined, simultaneous regulation of magnetic stimulus and mechanical pumping, the desired chemical release rate can easily be realized. For example, the dose release experimental data was well fitted by a mathematical sigmoidal model, exhibiting a typical dose-response relationship, which shows promise in providing significant guidance for on-demand drug delivery. To test the platform’s feasibility, our microfluidic device was employed in an experiment involving Escherichia coli culture under controlled antibiotic ciprofloxacin exposure, and the expected outcomes were successfully obtained. Our experimental results indicate that such a microfluidic device, with high accuracy and easy manipulation properties, can legitimately be characterized as active chemical release system.

  4. Microfluidic Device for Controllable Chemical Release via Field-Actuated Membrane Incorporating Nanoparticles

    KAUST Repository

    Wang, Xiang

    2013-01-01

    We report a robust magnetic-membrane-based microfluidic platform for controllable chemical release. The magnetic membrane was prepared by mixing polydimethylsiloxane (PDMS) and carbonyl-iron nanoparticles together to obtain a flexible thin film. With combined, simultaneous regulation of magnetic stimulus and mechanical pumping, the desired chemical release rate can easily be realized. For example, the dose release experimental data was well fitted by a mathematical sigmoidal model, exhibiting a typical dose-response relationship, which shows promise in providing significant guidance for on-demand drug delivery. To test the platform’s feasibility, our microfluidic device was employed in an experiment involving Escherichia coli culture under controlled antibiotic ciprofloxacin exposure, and the expected outcomes were successfully obtained. Our experimental results indicate that such a microfluidic device, with high accuracy and easy manipulation properties, can legitimately be characterized as active chemical release system.

  5. Surface state modulation through wet chemical treatment as a route to controlling the electrical properties of ZnO nanowire arrays investigated with XPS

    International Nuclear Information System (INIS)

    Lord, Alex M.; Maffeis, Thierry G.; Allen, Martin W.; Morgan, David; Davies, Philip R.; Jones, Daniel R.; Evans, Jonathan E.; Smith, Nathan A.; Wilks, Steve P.

    2014-01-01

    Highlights: • Direct measurement of the surface band bending exhibited by ZnO nanowires using monochromatic XPS. • Modulation of the surface depletion region using wet chemical treatment (EtOH, H 2 O 2 ). • The measured surface potential barrier agrees with electrical measurements of individual nanowires. • H 2 O 2 depletes the nanowire of charge carriers while EtOH donates electrons at the surface. • EtOH has the effect of restoring the surface potential barrier of oxidised nanowires. - Abstract: ZnO is a wide bandgap semiconductor that has many potential applications including solar cell electrodes, transparent thin film transistors and gas/biological sensors. Since the surfaces of ZnO materials have no amorphous or oxidised layers, they are very environmentally sensitive, making control of their semiconductor properties challenging. In particular, the electronic properties of ZnO nanostructures are dominated by surface effects while surface conduction layers have been observed in thin films and bulk crystals. Therefore, the ability to use the ZnO materials in a controlled way depends on the development of simple techniques to modulate their surface electronic properties. Here, we use monochromatic x-ray photoelectron spectroscopy (XPS) to investigate the use of different wet chemical treatments (EtOH, H 2 O 2 ) to control the electronic properties of ZnO nanowires by modulating the surface depletion region. The valence band and core level XPS spectra are used to explore the relationship between the surface chemistry of the nanowires and the surface band bending

  6. An Overt Chemical Protective Garment Reduces Thermal Strain Compared with a Covert Garment in Warm-Wet but Not Hot-Dry Environments

    Directory of Open Access Journals (Sweden)

    Matthew J. Maley

    2017-11-01

    Full Text Available Objectives: A commercial chemical, biological, radiological and nuclear (CBRN protective covert garment has recently been developed with the aim of reducing thermal strain. A covert CBRN protective layer can be worn under other clothing, with equipment added for full chemical protection when needed. However, it is unknown whether the covert garment offers any alleviation to thermal strain during work compared with a traditional overt ensemble. Therefore, the aim of this study was to compare thermal strain and work tolerance times during work in an overt and covert ensemble offering the same level of CBRN protection.Methods: Eleven male participants wore an overt (OVERT or covert (COVERT CBRN ensemble and walked (4 km·h−1, 1% grade for a maximum of 120 min in either a wet bulb globe temperature [WBGT] of 21, 30, or 37°C (Neutral, WarmWet and HotDry, respectively. The trials were ceased if the participants' gastrointestinal temperature reached 39°C, heart rate reached 90% of maximum, walking time reached 120 min or due to self-termination.Results: All participants completed 120 min of walking in Neutral. Work tolerance time was greater in OVERT compared with COVERT in WarmWet (P < 0.001, 116.5[9.9] vs. 88.9[12.2] min, respectively, though this order was reversed in HotDry (P = 0.003, 37.3[5.3] vs. 48.4[4.6] min, respectively. The rate of change in mean body temperature and mean skin temperature was greater in COVERT (0.025[0.004] and 0.045[0.010]°C·min−1, respectively compared with OVERT (0.014[0.004] and 0.027[0.007]°C·min−1, respectively in WarmWet (P < 0.001 and P = 0.028, respectively. However, the rate of change in mean body temperature and mean skin temperature was greater in OVERT (0.068[0.010] and 0.170[0.026]°C·min−1, respectively compared with COVERT (0.059[0.004] and 0.120[0.017]°C·min−1, respectively in HotDry (P = 0.002 and P < 0.001, respectively. Thermal sensation, thermal comfort, and ratings of perceived

  7. Chemical bath deposition of ZnO nanowire-nanoparticle composite electrodes for use in dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Ku, C-H; Wu, J-J [Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

    2007-12-19

    ZnO nanowire (NW)-layered basic zinc acetate (LBZA)/ZnO nanoparticle (NP) composite electrodes with different NP occupying extents have been synthesized using a simple wet-chemical route for use in dye-sensitized solar cells (DSSCs). By employing mercurochrome as the sensitizer, superior efficiencies ({eta}) of 1.27-2.37% are obtained using the ZnO NW-LBZA/ZnO NP composite electrodes composed of a 5.5 {mu}m thick NW array with different NP occupying extents in comparison with the ZnO NW DSSC ({eta} = 0.45%). It suggests that the ZnO NW-LBZA/ZnO NP composite films which possess a considerable enlarged surface area by NPs growth, without sacrificing electron transport efficiency of single-crystalline ZnO NWs at the same time, are promising photoanodes for use in DSSCs. In addition to the extent of NP occupation, the overall efficiency of the ZnO NW-LBZA/ZnO NP composite DSSC is also influenced by the thickness of the composite film as well as the LBZA fraction and the cracks within the composite. The fraction of LBZA affected by the NP growth period and post-annealing conditions is found to play a crucial role in electron transport through the composite anode. Up to now, a high efficiency DSSC of 3.2% is achieved using a mercurochrome-sensitized and 6.2 {mu}m thick NW-NP composite film.

  8. Physical, Chemical, and Biological Properties of Soil under Decaying Wood in a Tropical Wet Forest in Puerto Rico

    Science.gov (United States)

    Marcela Zalamea; Grizelle Gonzalez; D. Jean Lodge

    2016-01-01

    Decaying wood is related to nutrient cycling through its role as either a sink or source of nutrients. However, at micro scales, what is the effect of decaying logs on the physical, chemical,and biotic characteristics of the soil underneath? We took samples from a 0 to 5 cm depth under and a 50 cm distance away from decaying logs (Dacryodes excelsa and Swietenia...

  9. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Greil, Stefanie M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Lauermann, Iver, E-mail: Iver.lauermann@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Aziz, Emad F., E-mail: Emad.Aziz@helmholtz-berlin.d [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)

    2010-02-15

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  10. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    International Nuclear Information System (INIS)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-01-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  11. In situ investigation of wet chemical processes for chalcopyrite solar cells by L-edge XAS under ambient conditions

    Science.gov (United States)

    Greil, Stefanie M.; Lauermann, Iver; Ennaoui, Ahmed; Kropp, Timo; Lange, Kathrin M.; Weber, Matthieu; Aziz, Emad F.

    2010-02-01

    Two instrumental setups for in situ soft X-ray absorption spectroscopy in liquid systems are demonstrated in this work. One for investigating chemical reactions in solutions and a new one for the solid component of a liquid / (as in both / absorber) solid interface. We used these setups for investigating two production processes for chalcopyrite solar cells under ambient conditions, probing the L-edge of Zn and Cu. The first one is a flow cell with a silicon nitride membrane to study the chemical bath deposition process for Cd-free buffer layers. Examining the electronic structure of involved Zn complexes allows to determine the exact reaction mechanism taking place during this process. The second setup is a rotating disk for investigating the bath/absorber interface upon the etching process of superficial binary copper compounds of the absorber as a function of time. The time resolution of the chemical reaction demonstrated in this study ranges from the second to minute time scale.

  12. Evaluation of Wet Chemical ICP-AES Elemental Analysis Methods using Simulated Hanford Waste Samples-Phase I Interim Report

    International Nuclear Information System (INIS)

    Coleman, Charles J.; Edwards, Thomas B.

    2005-01-01

    The wet chemistry digestion method development for providing process control elemental analyses of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Melter Feed Preparation Vessel (MFPV) samples is divided into two phases: Phase I consists of: (1) optimizing digestion methods as a precursor to elemental analyses by ICP-AES techniques; (2) selecting methods with the desired analytical reliability and speed to support the nine-hour or less turnaround time requirement of the WTP; and (3) providing baseline comparison to the laser ablation (LA) sample introduction technique for ICP-AES elemental analyses that is being developed at the Savannah River National Laboratory (SRNL). Phase II consists of: (1) Time-and-Motion study of the selected methods from Phase I with actual Hanford waste or waste simulants in shielded cell facilities to ensure that the methods can be performed remotely and maintain the desired characteristics; and (2) digestion of glass samples prepared from actual Hanford Waste tank sludge for providing comparative results to the LA Phase II study. Based on the Phase I testing discussed in this report, a tandem digestion approach consisting of sodium peroxide fusion digestions carried out in nickel crucibles and warm mixed-acid digestions carried out in plastic bottles has been selected for Time-and-Motion study in Phase II. SRNL experience with performing this analytical approach in laboratory hoods indicates that well-trained cell operator teams will be able to perform the tandem digestions in five hours or less. The selected approach will produce two sets of solutions for analysis by ICP-AES techniques. Four hours would then be allocated for performing the ICP-AES analyses and reporting results to meet the nine-hour or less turnaround time requirement. The tandem digestion approach will need to be performed in two separate shielded analytical cells by two separate cell operator teams in order to achieve the nine-hour or less turnaround

  13. Electrospun Polymer Nanofibers Decorated with Noble Metal Nanoparticles for Chemical Sensing.

    Science.gov (United States)

    Chen, Chen; Tang, Yongan; Vlahovic, Branislav; Yan, Fei

    2017-12-01

    The integration of different noble metal nanostructures, which exhibit desirable plasmonic and/or electrocatalytic properties, with electrospun polymer nanofibers, which display unique mechanical and thermodynamic properties, yields novel hybrid nanoscale systems of synergistic properties and functions. This review summarizes recent advances on how to incorporate noble metal nanoparticles into electrospun polymer nanofibers and illustrates how such integration paves the way towards chemical sensing applications with improved sensitivity, stability, flexibility, compatibility, and selectivity. It is expected that further development of this field will eventually make a wide impact on many areas of research.

  14. Chemical modifications and stability of diamond nanoparticles resolved by infrared spectroscopy and Kelvin force microscopy

    Czech Academy of Sciences Publication Activity Database

    Kozak, Halyna; Remeš, Zdeněk; Houdková, Jana; Stehlík, Štěpán; Kromka, Alexander; Rezek, Bohuslav

    2013-01-01

    Roč. 15, č. 4 (2013), "1568-1"-"1568-9" ISSN 1388-0764 R&D Projects: GA ČR GAP108/12/0910; GA ČR GPP205/12/P331; GA MŠk LH12186 Institutional support: RVO:68378271 Keywords : diamond nanoparticles * chemical modification * GAR-FTIR * AFM * KFM * XPS Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.278, year: 2013 http://link.springer.com/article/10.1007%2Fs11051-013-1568-7

  15. The effect of ultrasonic irradiation on the crystallinity of nano-hydroxyapatite produced via the wet chemical method.

    Science.gov (United States)

    Barbosa, Michelle C; Messmer, Nigel R; Brazil, Tayra R; Marciano, Fernanda R; Lobo, Anderson O

    2013-07-01

    Nanohydroxyapatite (nHAp) powders were produced via aqueous precipitation by adopting four different experimental conditions, assisted or non-assisted by ultrasound irradiation (UI). The nHAp powders were characterized by X-ray diffraction, energy-dispersive X-ray fluorescence, Raman and attenuated total reflection Fourier transform infrared spectroscopies, which showed typical surface chemical compositions of nHAp. Analysis found strong connections between UI and the crystallization process, crystal growth properties, as well as correlations between calcination and substitution reactions. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Synthesis of silver nanoparticles by radiolysis, photolysis and chemical reduction of AgNO3 in Hibiscus sabdariffa infusion (karkade)

    International Nuclear Information System (INIS)

    Cataldo, Franco; Ursini, Ornella; Angelini, Giancarlo

    2016-01-01

    Silver nanoparticles of different average diameters were synthesized by γ-radiolysis, UV-photolysis and chemical reduction of AgNO 3 solutions in Hibiscus sabdariffa infusion commonly known as 'karkade'. The UV-photolysis was performed either by using a conventional Hg low pressure lamp emitting at 254 nm and also by using a new compact UV-LED source emitting at 360 nm. The kinetics rate constant of silver nanoparticles synthesis produced by γ-radiolysis and UV photolysis were determined and the average diameter of the resulting nanoparticles was estimated. (author)

  17. Eco-friendly and green synthesis of silver nanoparticles using leaf extract of Strychnos potatorum Linn.F. and their bactericidal activities

    OpenAIRE

    Kagithoju, Srikanth; Godishala, Vikram; Nanna, Rama Swamy

    2014-01-01

    Inspired green synthesis of metallic nanoparticles is evolving as an important branch of nanotechnology. Traditionally these are manufactured by wet chemical methods which require toxic and flammable chemicals. We report for the first time an economic and eco-friendly green synthesis of silver nanoparticles using Strychnos potatorum aqueous leaf extract from 3 mM silver nitrate solution. Nanoparticles thus formed are confirmed and characterized by using UV–Vis absorption spectroscopy, SEM and...

  18. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se2 thin-film solar cell absorbers

    Science.gov (United States)

    Lehmann, Jascha; Lehmann, Sebastian; Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch.; Bär, Marcus; Sadewasser, Sascha

    2014-12-01

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for "realistic" surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In1-xGax)Se2 thin films with an average x = [Ga]/([In] + [Ga]) = 0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH3-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is - apart from a slight change in surface composition - identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

  19. The effect of ultrasonic irradiation on the crystallinity of nano-hydroxyapatite produced via the wet chemical method

    International Nuclear Information System (INIS)

    Barbosa, Michelle C.; Messmer, Nigel R.; Brazil, Tayra R.; Marciano, Fernanda R.; Lobo, Anderson O.

    2013-01-01

    Nanohydroxyapatite (nHAp) powders were produced via aqueous precipitation by adopting four different experimental conditions, assisted or non-assisted by ultrasound irradiation (UI). The nHAp powders were characterized by X-ray diffraction, energy-dispersive X-ray fluorescence, Raman and attenuated total reflection Fourier transform infrared spectroscopies, which showed typical surface chemical compositions of nHAp. Analysis found strong connections between UI and the crystallization process, crystal growth properties, as well as correlations between calcination and substitution reactions. - Highlights: ► Nanohydroxyapatite powders were produced via aqueous precipitation. ► Three methodologies were compared, such as: dropwise, mixture and ultrasound irradiation (UI). ► Analysis found strong connections between UI and the crystallization process

  20. The effect of ultrasonic irradiation on the crystallinity of nano-hydroxyapatite produced via the wet chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Michelle C.; Messmer, Nigel R.; Brazil, Tayra R.; Marciano, Fernanda R.; Lobo, Anderson O., E-mail: loboao@yahoo.com

    2013-07-01

    Nanohydroxyapatite (nHAp) powders were produced via aqueous precipitation by adopting four different experimental conditions, assisted or non-assisted by ultrasound irradiation (UI). The nHAp powders were characterized by X-ray diffraction, energy-dispersive X-ray fluorescence, Raman and attenuated total reflection Fourier transform infrared spectroscopies, which showed typical surface chemical compositions of nHAp. Analysis found strong connections between UI and the crystallization process, crystal growth properties, as well as correlations between calcination and substitution reactions. - Highlights: ► Nanohydroxyapatite powders were produced via aqueous precipitation. ► Three methodologies were compared, such as: dropwise, mixture and ultrasound irradiation (UI). ► Analysis found strong connections between UI and the crystallization process.

  1. Chemical synthesis, phase transformation and magnetic proprieties of FePt and FePd nanoparticles

    International Nuclear Information System (INIS)

    Delattre, Anastasia

    2010-01-01

    This work aims at understanding the chemical synthesis of FePt and FePd nanoparticles (NPs), and at exploring how to implement the phase transformation from the chemically disordered to the L10 phase, without coalescence. Using hexadecanenitrile instead of oleylamine, we obtain NPs with a more homogenous internal composition, instead of core-shell NPs. Through a systematic study (designed experiment relying on Taguchi tables), we developed the FePd synthesis, while evidencing the role of each ligand and of the reductor. To induce the crystalline phase transformation while avoiding coalescence, we explored two ways. In the first one, atomic vacancies are introduced in the NPs through light ion irradiation, atomic mobility being ensured by annealing at moderate temperature (300 C). As a result, the blocking temperature is multiplied by 4, due to anisotropy enhancement. However, strong chemical ordering in the L10 phase cannot be achieved. The second approach relies on the dispersion of the NPs in a salt (NaCl) matrix, prior to annealing at 700 C: high chemical ordering is achieved, and the blocking temperature is beyond 400 C. We then developed a single-step process to remove the salt by dissolution in water and to re-disperse NPs in stable aqueous or organics solutions. These high magnetic anisotropy NPs are then readily available for further chemical or manipulation steps, with applied perspectives in areas such as data storage, or biology. (author)

  2. The Role of Electronic Excitations on Chemical Reaction Dynamics at Metal, Semiconductor and Nanoparticle Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Tully, John C. [Yale Univ., New Haven, CT (United States)

    2017-06-10

    Chemical reactions are often facilitated and steered when carried out on solid surfaces, essential for applications such as heterogeneous catalysis, solar energy conversion, corrosion, materials processing, and many others. A critical factor that can determine the rates and pathways of chemical reactions at surfaces is the efficiency and specificity of energy transfer; how fast does energy move around and where does it go? For reactions on insulator surfaces energy transfer generally moves in and out of vibrations of the adsorbed molecule and the underlying substrate. By contrast, on metal surfaces, metallic nanoparticles and semiconductors, another pathway for energy flow opens up, excitation and de-excitation of electrons. This so-called “nonadiabatic” mechanism often dominates the transfer of energy and can directly impact the course of a chemical reaction. Conventional computational methods such as molecular dynamics simulation do not account for this nonadiabatic behavior. The current DOE-BES funded project has focused on developing the underlying theoretical foundation and the computational methodology for the prediction of nonadiabatic chemical reaction dynamics at surfaces. The research has successfully opened up new methodology and new applications for molecular simulation. In particular, over the last three years, the “Electronic Friction” theory, pioneered by the PI, has now been developed into a stable and accurate computational method that is sufficiently practical to allow first principles “on-the-fly” simulation of chemical reaction dynamics at metal surfaces.

  3. Surge-Resistant Nanocomposite Enameled Wire Using Silica Nanoparticles with Binary Chemical Compositions on the Surface

    Directory of Open Access Journals (Sweden)

    Jeseung Yoo

    2015-01-01

    Full Text Available We developed polyesterimide (PEI nanocomposite enameled wires using surface-modified silica nanoparticles with binary chemical compositions on the surface. The modification was done using silanes assisted by ultrasound, which facilitated high density modification. Two different trimethoxysilanes were chosen for the modification on the basis of resemblance of chemical compositions on the silica surface to PEI varnish. The surface-modified silica was well dispersed in PEI varnish, which was confirmed by optical observation and viscosity measurement. The glass transition temperature of the silica-PEI nanocomposite increased with the silica content. The silica-dispersed PEI varnish was then used for enameled wire fabrication. The silica-PEI nanocomposite enameled wire exhibited a much longer lifetime compared to that of neat PEI enameled wire in partial discharge conditions.

  4. Studies on magnetic properties of chemically synthesized crystalline calcium ferrite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Debnath, A., E-mail: debnathanimesh@gmail.com [Department of Civil Engineering, National Institute of Technology Agartala, Jirania, West Tripura, 799046 India (India); Bera, A.; Saha, B. [Department of Physics, National Institute of Technology Agartala, Jirania, West Tripura 799046 (India); Chattopadhyay, K. K. [Department of Physics, Jadavpur University, Kolkata 700 032 (India)

    2016-05-23

    Spinel-type ferrites have taken a very important role for modern electronic industry. Most of these ferrites exhibit low-loss dielectric properties, high resistivity, low eddy current and also high temperature ferromagnetism. Calcium ferrite is one such important metal oxide which is environmentally safe, chemically stable, low cost and greatly abundant. This outstanding material of calcium ferrite is synthesized by a simple chemical precipitation method using NaOH as the precipitating agent. Ferric chloride anhydrous (FeCl{sub 3}) and Calcium chloride dihydrate (CaCl{sub 2}.2H{sub 2}O) were used as iron and calcium sources respectively. The samples were heated at 200°C for 8h to obtain homogeneous powder of Calcium ferrite. The powders were characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electrical microscopy (TEM), and Fourier transform infrared spectroscopic (FTIR) measurements. The polycrystalline nature of the sample was confirmed by X-ray diffraction study. The magnetic properties of the sample were investigated by vibrating sample magnetometer (VSM) measurements. Magnetization curve of the prepared sample depicts that as synthesized calcium ferrite nanoparticles have saturation magnetic moment of 1.74 emu/g and the coercivity of 35.08 Oe with superparamagnetic behavior. The synthesized calcium ferrite nanoparticles with such magnetic properties will be a candidate material for different applications in electronics and exploring its functionality in the field of recently developing semiconductor device physics and spintronics.

  5. Studies on magnetic properties of chemically synthesized crystalline calcium ferrite nanoparticles

    International Nuclear Information System (INIS)

    Debnath, A.; Bera, A.; Saha, B.; Chattopadhyay, K. K.

    2016-01-01

    Spinel-type ferrites have taken a very important role for modern electronic industry. Most of these ferrites exhibit low-loss dielectric properties, high resistivity, low eddy current and also high temperature ferromagnetism. Calcium ferrite is one such important metal oxide which is environmentally safe, chemically stable, low cost and greatly abundant. This outstanding material of calcium ferrite is synthesized by a simple chemical precipitation method using NaOH as the precipitating agent. Ferric chloride anhydrous (FeCl_3) and Calcium chloride dihydrate (CaCl_2.2H_2O) were used as iron and calcium sources respectively. The samples were heated at 200°C for 8h to obtain homogeneous powder of Calcium ferrite. The powders were characterized by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Transmission electrical microscopy (TEM), and Fourier transform infrared spectroscopic (FTIR) measurements. The polycrystalline nature of the sample was confirmed by X-ray diffraction study. The magnetic properties of the sample were investigated by vibrating sample magnetometer (VSM) measurements. Magnetization curve of the prepared sample depicts that as synthesized calcium ferrite nanoparticles have saturation magnetic moment of 1.74 emu/g and the coercivity of 35.08 Oe with superparamagnetic behavior. The synthesized calcium ferrite nanoparticles with such magnetic properties will be a candidate material for different applications in electronics and exploring its functionality in the field of recently developing semiconductor device physics and spintronics.

  6. Ion-irradiation induced chemical ordering of FePt and FePtAu nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Seetala, Naidu V. [Department of Physics, Grambling State University, RWE Jones Drive, Carver Hall 81, Grambling, LA 71245 (United States)]. E-mail: naidusv@gram.edu; Harrell, J.W. [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Lawson, Jeremy [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Nikles, David E. [MINT Center, University of Alabama, Tuscaloosa, AL 35487 (United States); Williams, John R. [Department of Physics, Auburn University, Auburn, AL 36849 (United States); Isaacs-Smith, Tamara [Department of Physics, Auburn University, Auburn, AL 36849 (United States)

    2005-12-15

    We have studied the effect of ion-beam irradiation on reducing the ordering temperature of FePt and FePtAu nanoparticles. FePt and FePt(Au14%) 4 nm particles dispersed on a Si-substrate were irradiated by 300 keV Al-ions with a dose of 1 x 10{sup 16} ions/cm{sup 2} at 43 {sup o}C using a water-cooled flange in order to minimize the vacancy migration and voids formation within the collision cascades. Partial chemical ordering has been observed in as-irradiated particles with coercivity of 60-130 Oe. Post-irradiation annealing at 220 {sup o}C enhanced chemical ordering in FePt nanoparticles with coercivity of 3500 Oe, magnetic anisotropy of 1.5 x 10{sup 7} erg/cc, and thermal stability factor of 130. A much higher 375 {sup o}C post-irradiation annealing was required in FePtAu, presumably because Au atoms were trapped at Fe/Pt lattice sites at lower temperatures. As the annealing temperature increased, anomalous features in the magnetization reversal curves were observed that disappeared at higher annealing temperatures.

  7. Mars Surveyor Program '01 Mars Environmental Compatibility Assessment wet chemistry lab: a sensor array for chemical analysis of the Martian soil

    Science.gov (United States)

    Kounaves, Samuel P.; Lukow, Stefan R.; Comeau, Brian P.; Hecht, Michael H.; Grannan-Feldman, Sabrina M.; Manatt, Ken; West, Steven J.; Wen, Xiaowen; Frant, Martin; Gillette, Tim

    2003-01-01

    The Mars Environmental Compatibility Assessment (MECA) instrument was designed, built, and flight qualified for the now canceled MSP (Mars Surveyor Program) '01 Lander. The MECA package consisted of a microscope, electrometer, material patch plates, and a wet chemistry laboratory (WCL). The primary goal of MECA was to analyze the Martian soil (regolith) for possible hazards to future astronauts and to provide a better understanding of Martian regolith geochemistry. The purpose of the WCL was to analyze for a range of soluble ionic chemical species and electrochemical parameters. The heart of the WCL was a sensor array of electrochemically based ion-selective electrodes (ISE). After 20 months storage at -23 degrees C and subsequent extended freeze/thawing cycles, WCL sensors were evaluated to determine both their physical durability and analytical responses. A fractional factorial calibration of the sensors was used to obtain slope, intercept, and all necessary selectivity coefficients simultaneously for selected ISEs. This calibration was used to model five cation and three anion sensors. These data were subsequently used to determine concentrations of several ions in two soil leachate simulants (based on terrestrial seawater and hypothesized Mars brine) and four actual soil samples. The WCL results were compared to simulant and soil samples using ion chromatography and inductively coupled plasma optical emission spectroscopy. The results showed that flight qualification and prolonged low-temperature storage conditions had minimal effects on the sensors. In addition, the analytical optimization method provided quantitative and qualitative data that could be used to accurately identify the chemical composition of the simulants and soils. The WCL has the ability to provide data that can be used to "read" the chemical, geological, and climatic history of Mars, as well as the potential habitability of its regolith.

  8. Wet chemical synthesis of quantum confined nanostructured tin oxide thin films by successive ionic layer adsorption and reaction technique

    Energy Technology Data Exchange (ETDEWEB)

    Murali, K.V., E-mail: kvmuralikv@gmail.com [School of Pure and Applied Physics, Department of Physics, Kannur University, Kerala 670327 (India); Department of Physics, Nehru Arts and Science College, Kanhangad, Kerala 671314 (India); Ragina, A.J. [School of Pure and Applied Physics, Department of Physics, Kannur University, Kerala 670327 (India); Department of Physics, Nehru Arts and Science College, Kanhangad, Kerala 671314 (India); Preetha, K.C. [School of Pure and Applied Physics, Department of Physics, Kannur University, Kerala 670327 (India); Department of Physics, Sree Narayana College, Kannur, Kerala 670007 (India); Deepa, K.; Remadevi, T.L. [School of Pure and Applied Physics, Department of Physics, Kannur University, Kerala 670327 (India); Department of Physics, Pazhassi Raja N.S.S. College, Mattannur, Kerala 670702 (India)

    2013-09-01

    Graphical abstract: - Highlights: • Quantum confined SnO{sub 2} thin films were synthesized at 80 °C by SILAR technique. • Film formation mechanism is discussed. • Films with snow like crystallite morphology offer high specific surface area. • The blue-shifted value of band gap confirmed the quantum confinement effect. • Present synthesis has advantages – low cost, low temperature and green friendly. - Abstract: Quantum confined nanostructured SnO{sub 2} thin films were synthesized at 353 K using ammonium chloride (NH{sub 4}Cl) and other chemicals by successive ionic layer adsorption and reaction technique. Film formation mechanism is discussed. Structural, morphological, optical and electrical properties were investigated and compared with the as-grown and annealed films fabricated without NH{sub 4}Cl solution. SnO{sub 2} films were polycrystalline with crystallites of tetragonal structure with grain sizes lie in the 5–8 nm range. Films with snow like crystallite morphology offer high specific surface area. The blue-shifted value of band gap of as-grown films confirmed the quantum confinement effect of grains. Refractive index of the films lies in the 2.1–2.3 range. Films prepared with NH{sub 4}Cl exhibit relatively lower resistivity of the order of 10{sup 0}–10{sup −1} Ω cm. The present synthesis has advantages such as low cost, low temperature and green friendly, which yields small particle size, large surface–volume ratio, and high crystallinity SnO{sub 2} films.

  9. Pore Scale Investigation of Wettability Alteration Through Chemically-Tuned Waterflooding in Oil-Wet Carbonate Rocks Using X-Ray Micro-Ct Imaging

    Science.gov (United States)

    Tawfik, M. S.; Karpyn, Z.

    2017-12-01

    Carbonate reservoirs host more than half of the remaining oil reserves worldwide. Due to their complex pore structure and intermediate to oil-wet nature, it is challenging to produce the remaining oil from these formations. For two decades, chemically tuned waterflooding (CTWF) has gained the attention of many researchers. Experimental, numerical, and field studies suggest that changes in ion composition of injected brine can increase oil recovery in carbonate reservoirs via wettability alteration. However, previous studies explaining the improvement in oil recovery by wettability alteration deduce wettability based on indirect measurements, including sessile drop contact angle measurements on polished rocks, relative permeability, chromatographic separation of SCN- and potential determining ions (PDIs), etc. CTWF literature offers no direct measurement of wettability alteration at the pore scale. This study proposes a direct pore-scale measurement of changes in interfacial curvatures before and after CTWF. Micro-coreflood experiments are performed to investigate the effect of injection brine salinity, ion composition and temperature on rock wettability at the pore scale. X-ray micro-CT scanning is used to obtain 3D image sets to calculate in-situ contact angle distributions. The study also aims to find a correlation between the magnitude of improvement in oil recovery at the macro-scale and the corresponding contact angle distribution at the pore-scale at different experimental conditions. Hence, macro-scale coreflood experiments are performed using the same conditions as the micro-corefloods. Macro-scale coreflood experiments have shown that brines with higher concentration of Ca2+, Mg2+ and SO42- ions have higher recoveries compared to standard seawater. This translates to wettability alteration into a more intermediate-wet state. This study enhances the understanding of the pore-scale physico-chemical mechanisms controlling wettability alteration via CTWF

  10. Wet cutting

    Energy Technology Data Exchange (ETDEWEB)

    Hole, B. [IMC Technical Services (United Kingdom)

    1999-08-01

    Continuous miners create dust and methane problems in underground coal mining. Control has usually been achieved using ventilation techniques as experiments with water based suppression have led to flooding and electrical problems. Recent experience in the US has led to renewed interest in wet head systems. This paper describes tests of the Hydraphase system by IMC Technologies. Ventilation around the cutting zone, quenching of hot ignition sources, dust suppression, the surface trial gallery tests, the performance of the cutting bed, and flow of air and methane around the cutting head are reviewed. 1 ref., 2 figs., 2 photos.

  11. Impacts of Environmental Nanoparticles on Chemical, Biological and Hydrological Processes in Terrestrial Ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Qafoku, Nikolla

    2012-01-01

    This chapter provides insights on nanoparticle (NP) influence or control on the extent and timescales of single or coupled physical, chemical, biological and hydrological reactions and processes that occur in terrestrial ecosystems. Examples taken from the literature that show how terrestrial NPs may determine the fate of the aqueous and sorbed (adsorbed or precipitated) chemical species of nutrients and contaminants, are also included in this chapter. Specifically, in the first section, chapter objectives, term definitions and discussions on size-dependent properties, the origin and occurrence of NP in terrestrial ecosystems and NP toxicity, are included. In the second section, the topic of the binary interactions of NPs of different sizes, shapes, concentrations and ages with the soil solution chemical species is covered, focusing on NP formation, stability, aggregation, ability to serve as sorbents, or surface-mediated precipitation catalysts, or electron donors and acceptors. In the third section, aspects of the interactions in the ternary systems composed of environmental NP, nutrient/contaminant chemical species, and the soil/sediment matrix are discussed, focusing on the inhibitory and catalytic effects of environmental NP on nutrient/contaminant advective mobility and mass transfer, adsorption and desorption, dissolution and precipitation and redox reactions that occur in terrestrial ecosystems. These three review sections are followed by a short summary of future research needs and directions, the acknowledgements, the list of the references, and the figures.

  12. Toxic effects of the interaction of titanium dioxide nanoparticles with chemicals or physical factors

    Science.gov (United States)

    Liu, Kui; Lin, Xialu; Zhao, Jinshun

    2013-01-01

    Due to their chemical stability and nonallergic, nonirritant, and ultraviolet protective properties, titanium dioxide (TiO2) nanoparticles (NPs) have been widely used in industries such as electronics, optics, and material sciences, as well as architecture, medicine, and pharmacology. However, increasing concerns have been raised in regards to its ecotoxicity and toxicity on the aquatic environment as well as to humans. Although insights have been gained into the effects of TiO2 NPs on susceptible biological systems, there is still much ground to be covered, particularly in respect of our knowledge of the effects of the interaction of TiO2 NPs with other chemicals or physical factors. Studies suggest that interactions of TiO2 NPs with other chemicals or physical factors may result in an increase in toxicity or adverse effects. This review highlights recent progress in the study of the interactive effects of TiO2 NPs with other chemicals or physical factors. PMID:23901269

  13. Synthesis of silver nanoparticles by chemical reduction at various fraction of MSA and their structure characterization

    Energy Technology Data Exchange (ETDEWEB)

    Diantoro, Markus, E-mail: m-diantoror@yahoo.com; Fitrianingsih, Rina, E-mail: m-diantoror@yahoo.com; Mufti, Nandang, E-mail: m-diantoror@yahoo.com; Fuad, Abdulloh, E-mail: m-diantoror@yahoo.com [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang (UM), Jl. Semarang No. 5 Malang 65145 (Indonesia)

    2014-03-24

    Nanosilver is currently one of the most common engineered nanomaterials and is used in many applications that lead to the release of silver nanoparticles and silver ions into aqueous systems. Nanosilver also possesses enhanced antimicrobial activity and bioavailability that may less environmental risk compared with other manufactured nanomaterials. Described in this research are the synthesis of silver nanoparticle produced by chemical reduction from silver nitrate (AgNO{sub 3}) solution. As a reducing agent, Sodium Borohydride (NaBH{sub 4}) was used and mercaptosuccinic Acid (MSA) as stabilizer to prevent the nanoparticle from aglomerating. It was also used two kinds of solvent, they are water and methanol. In typical experiment MSA was dissolve in methanol with a number of variation of molarity i.e. 0,03 M, 0,06 M, 0,12 M, 0,15 M, and the mixture was kept under vigorous stirring in an ice bath. A solution of silver nitrate of 340 mg in 6,792 ml water was added. A freshly prepared aqueous solution of sodium borohydride (756,6 mL in 100 mL of water) was added drop wisely. The solution was kept for half an hour for stirring and were allowed to settle down in methanol. The obtained samples then characterized by means of x-ray diffractometer, and scanning electron microscopy, as well as transmission electron microscopy to obtain their structures of silver nanoparticles, morphology, and sizes. It is shown that diameter of silver nanoparticle sized about 24.3 nm (Ag@MSA 0.03 M), 20.4 nm (Ag@MSA 0.06 M), 16.8 nm (Ag@MSA 0.12 M), 16.9 nm (Ag@MSA 0.15 M) which was calculated by Scherrer formula by taking the FWHM from fitting to Gaussian. The phases and lattice parameter showed that there is no significant change in its volume by increasing molarity of stabilizer. In contrast, the size of particles is decreasing.

  14. A lucrative chemical processing of bamboo leaf biomass to synthesize biocompatible amorphous silica nanoparticles of biomedical importance

    Science.gov (United States)

    Rangaraj, Suriyaprabha; Venkatachalam, Rajendran

    2017-06-01

    Synthesis of silica nanoparticles from natural resources/waste via cost effective route is presently one of the anticipating strategies for extensive applications. This study reports the low-cost indigenous production of silica nanoparticles from the leftover of bamboo (leaf biomass) through thermal combustion and alkaline extraction, and examination of physico-chemical properties and yield percentage using comprehensive characterization tools. The outcome of primed silica powder exhibits amorphous particles (average size: 25 nm) with high surface area (428 m2 g-1) and spherical morphology. Despite the yield percentage of silica nanoparticles from bamboo leave ash is 50.2%, which is less than rice husk ask resources (62.1%), the bamboo waste is only an inexpensive resource yielding high purity (99%). Synthesis of silica nanoparticles from natural resources/waste with the help of lucrative route is at present times one of the anticipating strategies for extensive applications. In vitro study on animal cell lines (MG-63) shows non-toxic nature of silica nanoparticles up to 125 µg mL-1. Hence, this study highlights the feasibility for the mass production of silica nanoparticles from bamboo leave waste rather using chemical precursor of silica for drug delivery and other medical applications.

  15. Mechanical control of the plasmon coupling with Au nanoparticle arrays fixed on the elastomeric film via chemical bond

    Science.gov (United States)

    Bedogni, Elena; Kaneko, Satoshi; Fujii, Shintaro; Kiguchi, Manabu

    2017-03-01

    We have fabricated Au nanoparticle arrays on the flexible poly(dimethylsiloxane) (PDMS) film. The nanoparticles were bound to the film via a covalent bond by a ligand exchange reaction. Thanks to the strong chemical bonding, highly stable and uniformly dispersed Au nanoparticle arrays were fixed on the PDMS film. The Au nanoparticle arrays were characterized by the UV-vis, scanning electron microscope (SEM) and surface enhanced Raman scattering (SERS). The UV-vis and SEM measurements showed the uniformity of the surface-dispersed Au nanoparticles, and SERS measurement confirmed the chemistry of the PDMS film. Reflecting the high stability and the uniformity of the Au nanoparticle arrays, the plasmon wavelength of the Au nanoparticles reversely changed with modulation of the interparticle distance, which was induced by the stretching of the PDMS film. The plasmon wavelength linearly decreased from 664 to 591 nm by stretching of 60%. The plasmon wavelength shift can be explained by the change in the strength of the plasmon coupling which is mechanically controlled by the mechanical strain.

  16. Wet chemical synthesis and luminescence in Ca5(PO4)3M:Eu2+ (M = Br, I) phosphors for solid state lighting

    Science.gov (United States)

    Mungmode, C. D.; Gahane, D. H.; Moharil, S. V.

    2018-05-01

    A simple wet chemical synthesis of Eu2+ activated Ca5(PO4)3Br and Ca5(PO4)3I phosphors and their photoluminescence is reported. Formation of Ca5(PO4)3Br is confirmed by X-ray diffraction (XRD). Synthesized phosphors are analyzed for photoluminescence (PL) spectrum. A bright blue emission is observed when phosphors are excited by near Ultra Violet (nUV) radiations. Photoluminescence emission spectrum for (Ca0.985Eu0.015)5(PO4)3Br is centered at 457 nm and for (Ca0.985Eu0.015)5(PO4)3 I it peaks at 455 nm when excited by 365 nm near UV radiation. Eu2+ luminescence in Ca5(PO4)3Br is reported for the first time. The phosphors can be efficiently excited by nUV radiations. This shows that phosphors may be used as blue phosphor in pcLED for Solid State Lighting.

  17. Annealing effect on the photoluminescence properties of ZnO nanorod array prepared by a PLD-assistant wet chemical method

    International Nuclear Information System (INIS)

    Wei Sufeng; Lian Jianshe; Wu Hua

    2010-01-01

    Well-aligned ZnO nanorod arrays were synthesized by a wet chemical method on the glass substrate with ZnO thin film as seed layer prepared by pulsed laser deposition. The effect of annealing temperature on the luminescence characteristics was investigated. As the annealing temperature increased, the photoluminescence properties show a general enhancing tendency. The nanorod array with high ultraviolet emission and negligible visible light emission (designated by the photoluminescence intensity ratio of ultraviolet to visible emission of 66.4) is obtained by annealing the sample at 700 deg. C for 1 h. Based on the results of X-ray photoelectron spectroscopy and photoluminescence spectra, the mechanisms of visible emission were discussed. - Research Highlights: → ZnO nanorod array with good crystallography, low defects concentration and good optical property was obtained after annealed at 700 deg. C for 1 h. → The transition from the conduction band to the O i level may be responsible for the yellow-green emission. → The yellow emission may originate from the presence of Zn(OH) 2 on the surface or the band transition from conduction band to V o Zn i level. → The transition from the Zn i level to the level should produce an orange emission or an orange-red emission.

  18. Improvement of the optical quality of site-controlled InAs quantum dots by a double stack growth technique in wet-chemically etched holes

    Energy Technology Data Exchange (ETDEWEB)

    Pfau, Tino Johannes; Gushterov, Aleksander; Reithmaier, Johann-Peter [Technische Physik, INA, Universitaet Kassel (Germany); Cestier, Isabelle; Eisenstein, Gadi [Electrical Engineering Dept., Technion, Haifa (Israel); Linder, Evgany; Gershoni, David [Solid State Institute and Physics Dept., Technion, Haifa (Israel)

    2010-07-01

    The optimization of the wet-chemically etching of holes and a special MBE growth stack technique allows enlarging the site-control of low density InAs QDs on GaAs substrates up to a buffer layer thickness of 55 nm. The strain of InAs QDs, grown in the etched holes, reduces the hole closing, so that a pre-patterned surface is conserved for the second QD layer. The distance of 50 nm GaAs between the two QD layers exceeds drastically the maximum vertical alignment based on pure strain coupling (20 nm). Compared to stacks with several QD layers, this method avoids electronic coupling between the different QD layers and reduces the problems to distinguish the dots of different layers optically. Confocal microphotoluminescence reveals a significant diminution of the low temperature photoluminescence linewidth of the second InAs QD layer to an average value of 505{+-}53 {mu}eV and a minimum width of 460 {mu}eV compared to 2 to 4 meV for QDs grown on thin buffer layers. The increase of the buffer layer thickness decreases the influence of the surface defects caused by prepatterning.

  19. Growth of ZnO nanowire arrays directly onto Si via substrate topographical adjustments using both wet chemical and dry etching methods

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Nathan A., E-mail: 523615@swansea.ac.uk [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom); Evans, Jon E.; Jones, Daniel R. [Multidisciplinary Nanotechnology Centre, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Lord, Alex M. [Centre for Nanohealth, College of Engineering, University of Swansea, Singleton Park, SA2 8PP United Kingdom (United Kingdom); Wilks, S.P. [Centre for Nanohealth, Department of Physics, College of Science, University of Swansea, Singleton Park SA2 8PP United Kingdom (United Kingdom)

    2015-03-15

    Highlights: • Arrays of catalyst-free ZnO NWs have been grown by CVD without seed layers on Si. • Si surface topography was altered by substrate etching, resulting in NW growth. • XPS analysis shows growth is related to topography and not surface contamination. • Using e-beam lithography with etching, selective nanowire growth is demonstrated. • Electrical measurements on the arrays show improved conduction through the Si. - Abstract: Arrays of CVD catalyst-free ZnO nanowires have been successfully grown without the use of seed layers, using both wet chemical and dry plasma etching methods to alter surface topography. XPS analysis indicates that the NW growth cannot be attributed to a substrate surface chemistry and is therefore directly related to the substrate topography. These nanowires demonstrate structural and optical properties typical of CVD ZnO nanowires. Moreover, the NW arrays exhibit a degree of vertical alignment of less than 20° from the substrate normal. Electrical measurements suggest an improved conduction path through the substrate over seed layer grown nanowires. Furthermore, the etching technique was combined with e-beam lithography to produce high resolution selective area nanowire growth. The ability to pattern uniform nanowires using mature dry etch technology coupled with the increased charge transport through the substrate demonstrates the potential of this technique in the vertical integration of nanowire arrays.

  20. Wet chemical treatment of boron doped emitters on n-type (1 0 0) c-Si prior to amorphous silicon passivation

    Energy Technology Data Exchange (ETDEWEB)

    Meddeb, H., E-mail: hosny.meddeb@gmail.com [KACST-Intel Consortium Center of Excellence in Nano-manufacturing Applications (CENA), Riyadh (Saudi Arabia); IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Research and Technology Center of Energy, Photovoltaic Department, Borj-Cedria Science and Technology Park, BP 95, 2050 (Tunisia); University of Carthage, Faculty of Sciences of Bizerta (Tunisia); Bearda, T.; Recaman Payo, M.; Abdelwahab, I. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Abdulraheem, Y. [Electrical Engineering Department, College of Engineering & Petroleum, Kuwait University, P.O. Box 5969, 13060 Safat (Kuwait); Ezzaouia, H. [Research and Technology Center of Energy, Photovoltaic Department, Borj-Cedria Science and Technology Park, BP 95, 2050 (Tunisia); Gordon, I.; Szlufcik, J. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Poortmans, J. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Department of Electrical Engineering (ESAT), K.U. Leuven, 3001 Leuven (Belgium); Faculty of Sciences, University of Hasselt, Martelarenlaan 42, 3500 Hasselt (Belgium)

    2015-02-15

    Highlights: • The influence of the cleaning process using different HF-based cleaning on the amorphous silicon passivation of homojunction boron doped emitters is analyzed. • The effect of boron doping level on surface characteristics after wet chemical cleaning: For heavily doped surfaces, the reduction in contact angle was less pronounced, which proves that such surfaces are more resistant to oxide formation and remain hydrophobic for a longer time. In the case of low HF concentration, XPS measurements show higher oxygen concentrations for samples with higher doping level, probably due to the incomplete removal of the native oxide. • Higher effective lifetime is achieved at lower doping for all considered different chemical pre-treatments. • A post-deposition annealing improves the passivation level yielding emitter saturation currents determined by Auger recombination in the order of 70 fA/cm{sup 2} and below. • The dominance of Auger recombination over other type of B-induced defects on lifetime quality in the case of our p+ emitter. - Abstract: The influence of the cleaning process on the amorphous silicon passivation of homojunction emitters is investigated. A significant variation in the passivation quality following different cleaning sequences is not observed, even though differences in cleaning performance are evident. These results point out the effectiveness of our cleaning treatment and provide a hydrogen termination for intrinsic amorphous silicon passivation. A post-deposition treatment improves the passivation level yielding emitter saturation currents determined by Auger recombination in the order of 70 fA/cm{sup 2} and below.

  1. Reliable wet-chemical cleaning of natively oxidized high-efficiency Cu(In,Ga)Se{sub 2} thin-film solar cell absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Jascha [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Potsdam Institute for Climate Impact Research (PIK), 14473 Potsdam (Germany); Lehmann, Sebastian, E-mail: sebastian.lehmann@ftf.lth.se [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Solid State Physics, Lund University, Box 118, S-22100 Lund (Sweden); Lauermann, Iver; Rissom, Thorsten; Kaufmann, Christian A.; Lux-Steiner, Martha Ch. [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Bär, Marcus, E-mail: marcus.baer@helmholtz-berlin.de [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institut für Physik und Chemie, Brandenburgische Technische Universität Cottbus-Senftenberg, Platz der Deutschen Einheit 1, 03046 Cottbus (Germany); Sadewasser, Sascha, E-mail: sascha.sadewasser@inl.int [Renewable Energies, Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga s/n, 4715-330 Braga (Portugal)

    2014-12-21

    Currently, Cu-containing chalcopyrite-based solar cells provide the highest conversion efficiencies among all thin-film photovoltaic (PV) technologies. They have reached efficiency values above 20%, the same performance level as multi-crystalline silicon-wafer technology that dominates the commercial PV market. Chalcopyrite thin-film heterostructures consist of a layer stack with a variety of interfaces between different materials. It is the chalcopyrite/buffer region (forming the p-n junction), which is of crucial importance and therefore frequently investigated using surface and interface science tools, such as photoelectron spectroscopy and scanning probe microscopy. To ensure comparability and validity of the results, a general preparation guide for “realistic” surfaces of polycrystalline chalcopyrite thin films is highly desirable. We present results on wet-chemical cleaning procedures of polycrystalline Cu(In{sub 1-x}Ga{sub x})Se{sub 2} thin films with an average x = [Ga]/([In] + [Ga]) = 0.29, which were exposed to ambient conditions for different times. The hence natively oxidized sample surfaces were etched in KCN- or NH{sub 3}-based aqueous solutions. By x-ray photoelectron spectroscopy, we find that the KCN treatment results in a chemical surface structure which is – apart from a slight change in surface composition – identical to a pristine as-received sample surface. Additionally, we discover a different oxidation behavior of In and Ga, in agreement with thermodynamic reference data, and we find indications for the segregation and removal of copper selenide surface phases from the polycrystalline material.

  2. In vivo stem cell tracking with imageable nanoparticles that bind bioorthogonal chemical receptors on the stem cell surface.

    Science.gov (United States)

    Lee, Sangmin; Yoon, Hwa In; Na, Jin Hee; Jeon, Sangmin; Lim, Seungho; Koo, Heebeom; Han, Sang-Soo; Kang, Sun-Woong; Park, Soon-Jung; Moon, Sung-Hwan; Park, Jae Hyung; Cho, Yong Woo; Kim, Byung-Soo; Kim, Sang Kyoon; Lee, Taekwan; Kim, Dongkyu; Lee, Seulki; Pomper, Martin G; Kwon, Ick Chan; Kim, Kwangmeyung

    2017-09-01

    It is urgently necessary to develop reliable non-invasive stem cell imaging technology for tracking the in vivo fate of transplanted stem cells in living subjects. Herein, we developed a simple and well controlled stem cell imaging method through a combination of metabolic glycoengineering and bioorthogonal copper-free click chemistry. Firstly, the exogenous chemical receptors containing azide (-N 3 ) groups were generated on the surfaces of stem cells through metabolic glycoengineering using metabolic precursor, tetra-acetylated N-azidoacetyl-d-mannosamine(Ac 4 ManNAz). Next, bicyclo[6.1.0]nonyne-modified glycol chitosan nanoparticles (BCN-CNPs) were prepared as imageable nanoparticles to deliver different imaging agents. Cy5.5, iron oxide nanoparticles and gold nanoparticles were conjugated or encapsulated to BCN-CNPs for optical, MR and CT imaging, respectively. These imageable nanoparticles bound chemical receptors on the Ac 4 ManNAz-treated stem cell surface specifically via bioorthogonal copper-free click chemistry. Then they were rapidly taken up by the cell membrane turn-over mechanism resulting in higher endocytic capacity compared non-specific uptake of nanoparticles. During in vivo animal test, BCN-CNP-Cy5.5-labeled stem cells could be continuously tracked by non-invasive optical imaging over 15 days. Furthermore, BCN-CNP-IRON- and BCN-CNP-GOLD-labeled stem cells could be efficiently visualized using in vivo MR and CT imaging demonstrating utility of our stem cell labeling method using chemical receptors. These results conclude that our method based on metabolic glycoengineering and bioorthogonal copper-free click chemistry can stably label stem cells with diverse imageable nanoparticles representing great potential as new stem cell imaging technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

    International Nuclear Information System (INIS)

    Sen, Sabyasachi; Gogurla, Narendar; Banerji, Pallab; Guha, Prasanta K.; Pramanik, Panchanan

    2015-01-01

    Graphical abstract: - Highlights: • β-FeSi 2 nano-particle was synthesized by reducing with Mg and by diluting with MgO. • XRD profile shows the iron di-silicide phase to be semiconducting β-FeSi 2 . • HRTEM and FESEM images indicate the β-FeSi 2 average particle size to be 60–70 nm. • Absorption, reflectance and PL spectroscopy show band gap to be direct 0.87 eV. • Nano-β-FeSi 2 is p-type with hole density of 4.38 × 10 18 cm −3 and mobility 8.9 cm 2 /V s. - Abstract: Nano-particles of β-FeSi 2 have been synthesized by chemical reduction of a glassy phase of [Fe 2 O 3 , 4SiO 2 ] by Mg-metal where MgO is used as diluent to prevent the agglomeration of nano crystallites into micro-particles and also act as a negative catalyst for the formation of other phases. The sample is characterized by XRD, FESEM, HRTEM, EDX, ultra-violet-visible-infrared and PL spectroscopy and electronic properties have been investigated by Hall measurement. XRD profile shows that the synthesized powder consists of purely β-FeSi 2 semiconducting phase. The average crystallite size of β-FeSi 2 is determined to be around 65.4 nm from XRD peaks as well as from FESEM also. The optical absorption and PL spectroscopy shows that synthesized β-FeSi 2 phase is a direct band gap semiconductor with a value of 0.87 eV. Hall measurements show that β-FeSi 2 nano-particles is p-type with hole concentration of 4.38 × 10 18 cm −3 and average hole mobility of 8.9 cm 2 /V s at 300 K

  4. Deposition of silver nanoparticles on multiwalled carbon nanotubes by chemical reduction process and their antimicrobial effects

    Energy Technology Data Exchange (ETDEWEB)

    Haider, Adawiya J., E-mail: adawiyahaider@yahoo.com [Nanotechnology and Advanced Materials Research Center, University of Technology, Baghdad, Republic of Iraq, 10066 (Iraq); Thamir, Amin D. [Production and Metallurgy department, University of Technology, University of Technology, Baghdad, Republic of Iraq, 10066 (Iraq); Ahmed, Duha S.; Mohammad, M. R. [Applied Physics department, University of Technology, University of Technology, Baghdad, Republic, of Iraq, 10066 (Iraq)

    2016-07-25

    In this paper, the functionalization of raw-MWCNTs involves oxidation reaction using concentrated acid mixture of HNO{sub 3}:H{sub 2}SO{sub 4} (1:3), via ultrasonic bath (170 W, 50 kHz) to obtain functional groups. Then Ag nanoparticles are decorated the outside over the surface of functionalized MWCNTs using a chemical reduction process resulting in the formation of(Ag/ MWCNTs) hybrid material. The results showed that outer diameter functionalized F-MWCNTs andAg nanoparticles size was about (11-80) nm and (10 to 25) nm, respectively using TEM and HRTEM. The crystallographic structure of MWCNTs using X-ray diffraction (XRD) analysis proved diffraction peaks at 38.1°, 44.3°, 64.7° and 77.4° degrees namely, Ag (111), Ag (200), Ag (220), and Ag (311) of the face-centered cubic lattice of Ag, respectively, excepting the peak at 2θ =25.6°, which correspond to the (0 0 2) reflection of the MWNTs are corresponding to Ag/MWNTs. The antimicrobial activities of Ag/MWCNTs hybrid using plate count method showed that decreasing a large number of bacteria colonies of E. coli and S. aureu with increasing the hybrid concentrations after incubation for 24 h in shaker incubator with percentage of inhibition approaching 100%.

  5. Altering protein surface charge with chemical modification modulates protein–gold nanoparticle aggregation

    International Nuclear Information System (INIS)

    Jamison, Jennifer A.; Bryant, Erika L.; Kadali, Shyam B.; Wong, Michael S.; Colvin, Vicki L.; Matthews, Kathleen S.; Calabretta, Michelle K.

    2011-01-01

    Gold nanoparticles (AuNP) can interact with a wide range of molecules including proteins. Whereas significant attention has focused on modifying the nanoparticle surface to regulate protein–AuNP assembly or influence the formation of the protein “corona,” modification of the protein surface as a mechanism to modulate protein–AuNP interaction has been less explored. Here, we examine this possibility utilizing three small globular proteins—lysozyme with high isoelectric point (pI) and established interactions with AuNP; α-lactalbumin with similar tertiary fold to lysozyme but low pI; and myoglobin with a different globular fold and an intermediate pI. We first chemically modified these proteins to alter their charged surface functionalities, and thereby shift protein pI, and then applied multiple methods to assess protein–AuNP assembly. At pH values lower than the anticipated pI of the modified protein, AuNP exposure elicits changes in the optical absorbance of the protein–NP solutions and other properties due to aggregate formation. Above the expected pI, however, protein–AuNP interaction is minimal, and both components remain isolated, presumably because both species are negatively charged. These data demonstrate that protein modification provides a powerful tool for modulating whether nanoparticle–protein interactions result in material aggregation. The results also underscore that naturally occurring protein modifications found in vivo may be critical in defining nanoparticle–protein corona compositions.

  6. Control of nanoparticle agglomeration through variation of the time-temperature profile in chemical vapor synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Djenadic, Ruzica; Winterer, Markus, E-mail: markus.winterer@uni-due.de [Universität Duisburg-Essen, Nanoparticle Process Technology, Faculty of Engineering and CENIDE (Germany)

    2017-02-15

    The influence of the time-temperature history on the characteristics of nanoparticles such as size, degree of agglomeration, or crystallinity is investigated for chemical vapor synthesis (CVS). A simple reaction-coagulation-sintering model is used to describe the CVS process, and the results of the model are compared to experimental data. Nanocrystalline titania is used as model material. Titania nanoparticles are generated from titanium-tetraisopropoxide (TTIP) in a hot-wall reactor. Pure anatase particles and mixtures of anatase, rutile (up to 11 vol.%), and brookite (up to 29 vol.%) with primary particle sizes from 1.7 nm to 10.5 nm and agglomerate particle sizes from 24.3 nm to 55.6 nm are formed depending on the particle time-temperature history. An inductively heated furnace with variable inductor geometry is used as a novel system to control the time-temperature profile in the reactor externally covering a large wall temperature range from 873 K to 2023 K. An appropriate choice of inductor geometry, i.e. time-temperature profile, can significantly reduce the degree of agglomeration. Other particle characteristics such as crystallinity are also substantially influenced by the time-temperature profile.

  7. Electrical properties of aluminum-doped zinc oxide (AZO) nanoparticles synthesized by chemical vapor synthesis

    International Nuclear Information System (INIS)

    Hartner, Sonja; Schulz, Christof; Wiggers, Hartmut; Ali, Moazzam; Winterer, Markus

    2009-01-01

    Aluminum-doped zinc oxide nanoparticles have been prepared by chemical vapor synthesis, which facilitates the incorporation of a higher percentage of dopant atoms, far above the thermodynamic solubility limit of aluminum. The electrical properties of aluminum-doped and undoped zinc oxide nanoparticles were investigated by impedance spectroscopy. The impedance is measured under hydrogen and synthetic air between 323 and 673 K. The measurements under hydrogen as well as under synthetic air show transport properties depending on temperature and doping level. Under hydrogen atmosphere, a decreasing conductivity with increasing dopant content is observed, which can be explained by enhanced scattering processes due to an increasing disorder in the nanocrystalline material. The temperature coefficient for the doped samples switches from positive temperature coefficient behavior to negative temperature coefficient behavior with increasing dopant concentration. In the presence of synthetic air, the conductivity firstly increases with increasing dopant content by six orders of magnitude. The origin of the increasing conductivity is the generation of free charge carriers upon dopant incorporation. It reaches its maximum at a concentration of 7.7% of aluminum, and drops for higher doping levels. In all cases, the conductivity under hydrogen is higher than under synthetic air and can be changed reversibly by changing the atmosphere.

  8. Electrical properties of aluminum-doped zinc oxide (AZO) nanoparticles synthesized by chemical vapor synthesis.

    Science.gov (United States)

    Hartner, Sonja; Ali, Moazzam; Schulz, Christof; Winterer, Markus; Wiggers, Hartmut

    2009-11-04

    Aluminum-doped zinc oxide nanoparticles have been prepared by chemical vapor synthesis, which facilitates the incorporation of a higher percentage of dopant atoms, far above the thermodynamic solubility limit of aluminum. The electrical properties of aluminum-doped and undoped zinc oxide nanoparticles were investigated by impedance spectroscopy. The impedance is measured under hydrogen and synthetic air between 323 and 673 K. The measurements under hydrogen as well as under synthetic air show transport properties depending on temperature and doping level. Under hydrogen atmosphere, a decreasing conductivity with increasing dopant content is observed, which can be explained by enhanced scattering processes due to an increasing disorder in the nanocrystalline material. The temperature coefficient for the doped samples switches from positive temperature coefficient behavior to negative temperature coefficient behavior with increasing dopant concentration. In the presence of synthetic air, the conductivity firstly increases with increasing dopant content by six orders of magnitude. The origin of the increasing conductivity is the generation of free charge carriers upon dopant incorporation. It reaches its maximum at a concentration of 7.7% of aluminum, and drops for higher doping levels. In all cases, the conductivity under hydrogen is higher than under synthetic air and can be changed reversibly by changing the atmosphere.

  9. Deposition of silver nanoparticles on multiwalled carbon nanotubes by chemical reduction process and their antimicrobial effects

    Science.gov (United States)

    Haider, Adawiya J.; Thamir, Amin D.; Ahmed, Duha S.; Mohammad, M. R.

    2016-07-01

    In this paper, the functionalization of raw-MWCNTs involves oxidation reaction using concentrated acid mixture of HNO3:H2SO4 (1:3), via ultrasonic bath (170 W, 50 kHz) to obtain functional groups. Then Ag nanoparticles are decorated the outside over the surface of functionalized MWCNTs using a chemical reduction process resulting in the formation of(Ag/ MWCNTs) hybrid material. The results showed that outer diameter functionalized F-MWCNTs andAg nanoparticles size was about (11-80) nm and (10 to 25) nm, respectively using TEM and HRTEM. The crystallographic structure of MWCNTs using X-ray diffraction (XRD) analysis proved diffraction peaks at 38.1°, 44.3°, 64.7° and 77.4° degrees namely, Ag (111), Ag (200), Ag (220), and Ag (311) of the face-centered cubic lattice of Ag, respectively, excepting the peak at 2θ =25.6°, which correspond to the (0 0 2) reflection of the MWNTs are corresponding to Ag/MWNTs. The antimicrobial activities of Ag/MWCNTs hybrid using plate count method showed that decreasing a large number of bacteria colonies of E. coli and S. aureu with increasing the hybrid concentrations after incubation for 24h in shaker incubator with percentage of inhibition approaching 100%.

  10. Preparation of high surface area and high conductivity polyaniline nanoparticles using chemical oxidation polymerization technique

    Science.gov (United States)

    Budi, S.; Yusmaniar; Juliana, A.; Cahyana, U.; Purwanto, A.; Imaduddin, A.; Handoko, E.

    2018-03-01

    In this work, polyaniline nanoparticles were synthesized using a chemical oxidation polymerization technique. The ammonium peroxydisulfate (APS)/aniline ratio, APS dropping time, and polymerization temperature were optimized to increase the surface area and conductivity of the polyaniline.The Fourier-transform infrared (FTIR) spectrum confirmed the formation of emeraldine salt polyaniline. X-ray diffraction (XRD) patterns indicated that amorphous and crystalline phases of the polyaniline were formed with crystallinity less than 40%. Scanning electron microscope (SEM) micrographs showed that the finest nanoparticles with uniform size distribution were obtained at the polymerization temperature of 0°C. A surface area analyzer (SAA) showed that the highest Brunauer-Emmett-Teller surface area (SBET ) of 42.14 m2/gwas obtained from an APS/aniline ratio of 0.75 with a dropping time of 0 s at a polymerization temperature of 0°C. A four-point probe measurement conducted at 75–300K indicated relatively high conductivity of the semiconductor characteristic of the polyaniline.

  11. Copper nanoparticles mediated by chitosan: synthesis and characterization via chemical methods.

    Science.gov (United States)

    Usman, Muhammad Sani; Ibrahim, Nor Azowa; Shameli, Kamyar; Zainuddin, Norhazlin; Yunus, Wan Md Zin Wan

    2012-12-14

    Herein we report a synthesis of copper nanoparticles (Cu-NPs) in chitosan (Cts) media via a chemical reaction method. The nanoparticles were synthesized in an aqueous solution in the presence of Cts as stabilizer and CuSO(4)·5H(2)O precursor. The synthesis proceeded with addition of NaOH as pH moderator, ascorbic acid as antioxidant and hydrazine( )as the reducing agent. The characterization of the prepared NPs was done using ultraviolet-visible spectroscopy, which showed a 593 nm copper band. The Field Emission Scanning Electron Microscope (FESEM) images were also observed, and found to be in agreement with the UV-Vis result, confirming the formation of metallic Cu-NPs. The mean size of the Cu-NPs was estimated to be in the range of 35-75 nm using X-ray diffraction. XRD was also used in analysis of the crystal structure of the NPs. The interaction between the chitosan and the synthesized NPs was studied using Fourier transform infrared (FT-IR) spectroscopy, which showed the capping of the NPs by Cts.

  12. A comparison of chemical structures of soot precursor nanoparticles from liquid fuel combustion in flames and engine

    International Nuclear Information System (INIS)

    Paul, Bireswar; Datta, Amitava; Datta, Aparna; Saha, Abhijit

    2013-01-01

    A comparative study of the chemical structures of soot precursor nanoparticles from the liquid fuel flame and engine exhaust has been performed in this work to establish an association between the particles from both the sources. Different ex-situ measurement techniques have been used to characterize the nanoparticles in samples collected from the laboratory petrol/air and iso-octane/air flames, as well as from a gasoline engine. The TEM images of the sampled material along with the EDS spectra corroborate the existence of carbonaceous nanoparticles. The nature of the UV absorption and fluorescence spectra of the samples from the iso-octane flame environment further confirms the sampled materials to be soot precursor nanoparticles. The DLS size distribution of the particles shows them to be below 10 nm size. FTIR spectrum of the precursor nanoparticles collected form the non-sooting zone of the flame and that of fully grown soot particles show few similarities and dissimilarities among them. The soot particles are found to be much more aromatized as compared to its precursor nanoparticles. The presence of carbonyl functional group (C=O) at around 1,720 cm −1 has been observed in soot precursor nanoparticles, while such oxygenated functional groups are not prominent in soot structure. The absorption (UV and IR) and fluorescence spectra of the carbonaceous material collected from the gasoline engine exhaust show many resemblances with those of soot precursor nanoparticles from flames. These spectroscopic resemblances of the soot precursor nanoparticles from the flame environment and engine exhaust gives the evidence that the in-cylinder combustion is the source of these particles in the engine exhaust.

  13. Influence of physical and chemical polymer-filler bonds on wet skid resistance and related properties of passenger car tire treads

    NARCIS (Netherlands)

    Cichomski, E.M.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.; Tolpekina, T.V.; Schultz, S.M.

    2012-01-01

    Knowledge about the influence of rubber – filler interactions on the wet skid behavior of tire treads is insufficient, in order to quickly develop new compounds with improved wet skid performance. The rubber compound used for a tire tread is in fact a composite material of which the dynamic

  14. Highly sensitive methanol chemical sensor based on undoped silver oxide nanoparticles prepared by a solution method

    International Nuclear Information System (INIS)

    Rahman, M.M.; Khan, S.B.; Asiri, A.M.; Jamal, A.; Faisal, M.

    2012-01-01

    We have prepared silver oxide nanoparticles (NPs) by a simple solution method using reducing agents in alkaline medium. The resulting NPs were characterized by UV-vis and FT-IR spectroscopy, X-ray powder diffraction, and field-emission scanning electron microscopy. They were deposited on a glassy carbon electrode to give a sensor with a fast response towards methanol in liquid phase. The sensor also displays good sensitivity and long-term stability, and enhanced electrochemical response. The calibration plot is linear (r 2 = 0.8294) over the 0.12 mM to 0.12 M methanol concentration range. The sensitivity is ∼ 2.65 μAcm -2 mM -1 , and the detection limit is 36.0 μM (at a SNR of 3). We also discuss possible future prospective uses of this metal oxide semiconductor nanomaterial in terms of chemical sensing. (author)

  15. Chemical/structural characterization of carbon nanoparticles produced by laser pyrolysis and used for nanotube growth

    International Nuclear Information System (INIS)

    Orlanducci, S.; Valentini, F.; Piccirillo, S.; Terranova, M.L.; Botti, S.; Ciardi, R.; Rossi, M.; Palleschi, G.

    2004-01-01

    Carbon nanoparticles produced by CO 2 laser pyrolysis have been investigated using morphological and structural probes such as high-resolution scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and electron diffraction, as well as chemical probes, such as gas chromatography-mass spectrometry and fast atom bombardment-mass spectrometry. The produced particles resulted to have a spherical shape and a diameter of about 50 nm with graphitic domains of the order of 80 A. They contain appreciable fractions of polycyclic aromatic hydrocarbons, which can be extracted with toluene, as well as fullerene units. The implications of these results for the use of carbon nanopowders in the carbon nanotube synthesis are also discussed

  16. Chemical characterization, nano-particle mineralogy and particle size distribution of basalt dust wastes

    Energy Technology Data Exchange (ETDEWEB)

    Dalmora, Adilson C. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração. Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Institute for Environmental Assessment and Water Studies (IDÆA), Spanish National Research Council (CSIC), C/Jordi Girona 18-26, 08034 Barcelona (Spain); Ramos, Claudete G.; Oliveira, Marcos L.S. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração. Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Teixeira, Elba C. [Fundação Estadual de Proteção Ambiental Henrique Luis Roessler, Porto Alegre, RS (Brazil); Kautzmann, Rubens M.; Taffarel, Silvio R. [Laboratory of Environmental Researches and Nanotechnology Development, Centro Universitário La Salle, Mestrado em Avaliação de Impactos Ambientais em Mineração. Victor Barreto, 2288 Centro 92010-000, Canoas, RS (Brazil); Brum, Irineu A.S. de [Universidade Federal do Rio Grande do Sul, Escola de Engenharia, Departamento de Metalurgia, Centro de Tecnologia, Av. Bento Gonçalves, 9500. Bairro Agronomia. CEP: 91501-970 Porto Alegre, RS (Brazil); and others

    2016-01-01

    Understanding the geochemistry of basalt alteration is central to the study of agriculture systems. Various nano-minerals play an important role in the mobilization of contaminants and their subsequent uptake by plants. We present a new analytical experimental approach in combination with an integrated analytical protocol designed to study basalt alteration processes. Recently, throughout the world, ultra-fine and nano-particles derived from basalt dust wastes (BDW) during “stonemeal” soil fertilizer application have been of great concern for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the Nova Prata mining district in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/Energy Dispersive Spectroscopy (EDS)/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM/EDS), and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO{sub 2}, Al{sub 2}O{sub 3}, and Fe{sub 2}O{sub 3,} with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition, we have identified a number of trace metals such as Cd, Cu, Cr, and Zn, that are preferentially concentrated into the finer, inhalable, dust fraction and, thus, could present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle

  17. Chemical characterization, nano-particle mineralogy and particle size distribution of basalt dust wastes

    International Nuclear Information System (INIS)

    Dalmora, Adilson C.; Ramos, Claudete G.; Oliveira, Marcos L.S.; Teixeira, Elba C.; Kautzmann, Rubens M.; Taffarel, Silvio R.; Brum, Irineu A.S. de

    2016-01-01

    Understanding the geochemistry of basalt alteration is central to the study of agriculture systems. Various nano-minerals play an important role in the mobilization of contaminants and their subsequent uptake by plants. We present a new analytical experimental approach in combination with an integrated analytical protocol designed to study basalt alteration processes. Recently, throughout the world, ultra-fine and nano-particles derived from basalt dust wastes (BDW) during “stonemeal” soil fertilizer application have been of great concern for their possible adverse effects on human health and environmental pollution. Samples of BDW utilized were obtained from companies in the Nova Prata mining district in southern Brazil for chemical characterization and nano-mineralogy investigation, using an integrated application of advanced characterization techniques such as X-ray diffraction (XRD), High Resolution-Transmission Electron microscopy (HR-TEM)/Energy Dispersive Spectroscopy (EDS)/(selected-area diffraction pattern) SAED, Field Emission-Scanning Electron Microscopy (FE-SEM/EDS), and granulometric distribution analysis. The investigation has revealed that BDW materials are dominated by SiO 2 , Al 2 O 3 , and Fe 2 O 3, with a complex micromineralogy including alkali feldspar, augite, barite, labradorite, hematite, heulandrite, gypsum, kaolinite, quartz, and smectite. In addition, we have identified a number of trace metals such as Cd, Cu, Cr, and Zn, that are preferentially concentrated into the finer, inhalable, dust fraction and, thus, could present a health hazard in the urban areas around the basalt mining zone. The implication of this observation is that use of these nanometric-sized particulates as soil fertilizer may present different health challenges to those of conventional fertilizers, inviting future work regarding the relative toxicities of these materials. Our investigation on the particle size distribution, nano-particle mineralogy and chemical

  18. EFFECT OF SILVER NANOPARTICLES ON THE PHYSICAL AND CHEMICAL PROPERTIES OF PLANT OILS AND THEIR ANTIMICROBIAL ACTIVITY

    Directory of Open Access Journals (Sweden)

    V. M. Minarchenko

    2017-12-01

    Full Text Available The aim of our research was to investigate the influence of silver nanoparticles on the physical and chemical features of plant oils of dogrose, flax, cedar, amaranth and watermelon and their antimicrobial activity. Plant oils were saturated with silver nanoparticles using electron-beam technology for depositing a molecular stream of metal in a vacuum. To characterize the rancidity of plant oils, the acid, iodine, peroxide, ester and saponification values were determined. A sharp drop in the iodine number and an increase in the peroxide number in oils saturated with silver nanoparticles were observed, as compared to pure oils, indicating a decrease in the number of unsaturated bonds in fatty acids and the formation of peroxides in oils. All pure plant oils and a separate sample of silver nanoparticles suppressed the growth of only E. faecalis colonies. Plant oils that were saturated with silver nanoparticles delayed the growth of S. aureus, S. epidermidis, E. faecalis, E. coli, P. aeruginosa, and C. albicans; the greatest delay in the growth of colonies was caused by flaxseed oil. Thus, the features of the plant oils under study essentially changed after they are aturated with silver nanoparticles. It can be assumed that the metal acted as a catalyst for peroxide oxidation of lipids in the investigated plant oil samples, the products of which caused toxic effects on cultures of bacteria and fungi in the experiment.

  19. Cobalt surface modification during γ-Fe{sub 2}O{sub 3} nanoparticle synthesis by chemical-induced transition

    Energy Technology Data Exchange (ETDEWEB)

    Li, Junming [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Li, Jian, E-mail: aizhong@swu.edu.cn [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Chen, Longlong; Lin, Yueqiang; Liu, Xiaodong; Gong, Xiaomin [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Li, Decai [School of Mechanical and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China)

    2015-02-01

    In the chemical-induced transition of FeCl{sub 2} solution, the FeOOH/Mg(OH){sub 2} precursor was transformed into spinel structured γ-Fe{sub 2}O{sub 3} crystallites, coated with a FeCl{sub 3}·6H{sub 2}O layer. CoCl{sub 2} surface modified γ-Fe{sub 2}O{sub 3} nanoparticles were prepared by adding Co(NO{sub 3}){sub 2} during the synthesis. CoFe{sub 2}O{sub 4} modified γ-Fe{sub 2}O{sub 3} nanoparticles were prepared by adding NaOH during the surface modification with Co(NO{sub 3}){sub 2}. The CoFe{sub 2}O{sub 4} layer grew epitaxially on the γ-Fe{sub 2}O{sub 3} crystallite to form a composite crystallite, which was coated by CoCl{sub 2}·6H{sub 2}O. The composite could not be distinguished using X-ray diffraction or transmission electron microscopy, since CoFe{sub 2}O{sub 4} and γ-Fe{sub 2}O{sub 3} possess similar spinel structures and lattice constants. X-ray photoelectron spectroscopy was used to distinguish them. The saturation magnetization and coercivity of the spinel structured γ-Fe{sub 2}O{sub 3}-based nanoparticles were related to the grain size. - Highlights: • γ-Fe{sub 2}O{sub 3} nanoparticles were synthesized by chemical induced transition. • CoCl{sub 2} modified nanoparticles were prepared by additional Co(NO{sub 3}){sub 2} during synthesization. • CoFe{sub 2}O{sub 4} modified nanoparticles were prepared by additional Co(NO{sub 3}){sub 2} and NaOH. • The magnetism of the nanoparticles is related to the grain size.

  20. Cobalt surface modification during γ-Fe2O3 nanoparticle synthesis by chemical-induced transition

    International Nuclear Information System (INIS)

    Li, Junming; Li, Jian; Chen, Longlong; Lin, Yueqiang; Liu, Xiaodong; Gong, Xiaomin; Li, Decai

    2015-01-01

    In the chemical-induced transition of FeCl 2 solution, the FeOOH/Mg(OH) 2 precursor was transformed into spinel structured γ-Fe 2 O 3 crystallites, coated with a FeCl 3 ·6H 2 O layer. CoCl 2 surface modified γ-Fe 2 O 3 nanoparticles were prepared by adding Co(NO 3 ) 2 during the synthesis. CoFe 2 O 4 modified γ-Fe 2 O 3 nanoparticles were prepared by adding NaOH during the surface modification with Co(NO 3 ) 2 . The CoFe 2 O 4 layer grew epitaxially on the γ-Fe 2 O 3 crystallite to form a composite crystallite, which was coated by CoCl 2 ·6H 2 O. The composite could not be distinguished using X-ray diffraction or transmission electron microscopy, since CoFe 2 O 4 and γ-Fe 2 O 3 possess similar spinel structures and lattice constants. X-ray photoelectron spectroscopy was used to distinguish them. The saturation magnetization and coercivity of the spinel structured γ-Fe 2 O 3 -based nanoparticles were related to the grain size. - Highlights: • γ-Fe 2 O 3 nanoparticles were synthesized by chemical induced transition. • CoCl 2 modified nanoparticles were prepared by additional Co(NO 3 ) 2 during synthesization. • CoFe 2 O 4 modified nanoparticles were prepared by additional Co(NO 3 ) 2 and NaOH. • The magnetism of the nanoparticles is related to the grain size

  1. Effect of ultrasound treatment on the wet heating Maillard reaction between mung bean [Vigna radiate (L.)] protein isolates and glucose and on structural and physico-chemical properties of conjugates.

    Science.gov (United States)

    Wang, Zhongjiang; Han, Feifei; Sui, Xiaonan; Qi, Baokun; Yang, Yong; Zhang, Hui; Wang, Rui; Li, Yang; Jiang, Lianzhou

    2016-03-30

    The objective of this study was to determine the effect of ultrasound treatment on the wet heating Maillard reaction between mung bean protein isolates (MBPIs) and glucose, and on structural and physico-chemical properties of the conjugates. The degree of glycosylation of MBPI-glucose conjugates treated by ultrasound treatment and wet heating (MBPI-GUH) was higher than that of MBPI-glucose conjugates only treated by wet heating (MBPI-GH). Solubility, emulsification activity, emulsification stability and surface hydrophobicity of MBPI-GUH were higher than that of MBPI-GH. Grafted MBPIs had a lower content of α-helix and unordered coil, but a higher content of β-sheet and β-turn structure than MBPIs. No significant structural changes were observed in β-turn and random coil structure of MBPI-GUH, while α-helix content increased with ultrasonic time, and decreased at 300 W ultrasonic power with the increase of β-sheet. MBPI-GUH had a less compact tertiary structure compared to MBPI-GH and MBPI. Grafting MBPIs with glucose formed conjugates of higher molecular weight, while no significant changes were observed in electrophoresis profiles of MBPI-GUH. Ultrasound-assisted wet heating Maillard reaction between MBPIs and glucose could be a promising way to improve functional properties of MBPIs. © 2015 Society of Chemical Industry.

  2. A new methodology for studying nanoparticle interactions in biological systems: Dispersing titania in biocompatible media using chemical stabilisers

    Science.gov (United States)

    Ramirez-Garcia, Sonia; Chen, Lan; Morris, Michael A.; Dawson, Kenneth A.

    2011-11-01

    We report here a highly successful and original protocol for the dispersion of nanoparticles in biocompatible fluids for in vitro and in vivo studies of the nanoparticle-biology interaction. Titania is chosen as a suitable model as it is one of the priority materials listed by the OECD and small particles of the anatase structure are extensively used as e.g. photocatalysts in solar cells. Consequently, its delivery into the environment and its interaction with biological organisms is unavoidable. Therefore, its biological effect needs to be understood. In this work, we prepared stable nanoparticle dispersions of anatase aggregates using citrate stabilisations between 45 and 55 nm at concentrations of up to 10 mg mL-1. The optimum pH for this type of suspension was 7, resulting in ζ-potentials of approximately -50 mV. The stabilised aggregates were the subject of dialysis to produce stable dispersions without the chemical stabiliser, thus allowing studies in the absence of potentially toxic chemicals. Different sizing techniques such as Dynamic Light Scattering (DLS), Nanoparticle Tracking Analysis (NTA) and Differential Centrifuge Sedimentation (DCS) were used to characterise the different suspensions. The results obtained with each of these techniques are compared and a critical analysis of the suitability of each technique is given.We report here a highly successful and original protocol for the dispersion of nanoparticles in biocompatible fluids for in vitro and in vivo studies of the nanoparticle-biology interaction. Titania is chosen as a suitable model as it is one of the priority materials listed by the OECD and small particles of the anatase structure are extensively used as e.g. photocatalysts in solar cells. Consequently, its delivery into the environment and its interaction with biological organisms is unavoidable. Therefore, its biological effect needs to be understood. In this work, we prepared stable nanoparticle dispersions of anatase aggregates

  3. The structural evolution and diffusion during the chemical transformation from cobalt to cobalt phosphide nanoparticles

    KAUST Repository

    Ha, Don-Hyung

    2011-01-01

    We report the structural evolution and the diffusion processes which occur during the phase transformation of nanoparticles (NPs), ε-Co to Co 2P to CoP, from a reaction with tri-n-octylphosphine (TOP). Extended X-ray absorption fine structure (EXAFS) investigations were used to elucidate the changes in the local structure of cobalt atoms which occur as the chemical transformation progresses. The lack of long-range order, spread in interatomic distances, and overall increase in mean-square disorder compared with bulk structure reveal the decrease in the NP\\'s structural order compared with bulk structure, which contributes to their deviation from bulk-like behavior. Results from EXAFS show both the Co2P and CoP phases contain excess Co. Results from EXAFS, transmission electron microscopy, X-ray diffraction, and density functional theory calculations reveal that the inward diffusion of phosphorus is more favorable at the beginning of the transformation from ε-Co to Co2P by forming an amorphous Co-P shell, while retaining a crystalline cobalt core. When the major phase of the sample turns to Co 2P, the diffusion processes reverse and cobalt atom out-diffusion is favored, leaving a hollow void, characteristic of the nanoscale Kirkendall effect. For the transformation from Co2P to CoP theory predicts an outward diffusion of cobalt while the anion lattice remains intact. In real samples, however, the Co-rich nanoparticles continue Kirkendall hollowing. Knowledge about the transformation method and structural properties provides a means to tailor the synthesis and composition of the NPs to facilitate their use in applications. © 2011 The Royal Society of Chemistry.

  4. Rapid, Efficient and Versatile Strategies for Functionally Sophisticated Polymers and Nanoparticles: Degradable Polyphosphoesters and Anisotropic Distribution of Chemical Functionalities

    Science.gov (United States)

    Zhang, Shiyi

    The overall emphasis of this dissertation research included two kinds of asymmetrically-functionalized nanoparticles with anisotropic distributions of chemical functionalities, three degradable polymers synthesized by organocatalyzed ring-opening polymerizations, and two polyphosphoester-based nanoparticle systems for various biomedical applications. Inspired by the many hierarchical assembly processes that afford complex materials in Nature, the construction of asymmetrically-functionalized nanoparticles with efficient surface chemistries and the directional organization of those building blocks into complex structures have attracted much attention. The first method generated a Janus-faced polymer nanoparticle that presented two orthogonally click-reactive surface chemistries, thiol and azido. This robust method involved reactive functional group transfer by templating against gold nanoparticle substrates. The second method produced nanoparticles with sandwich-like distribution of crown ether functionalities through a stepwise self-assembly process that utilized crown ether-ammonium supramolecular interactions to mediate inter-particle association and the local intra-particle phase separation of unlike hydrophobic polymers. With the goal to improve the efficiency of the production of degradable polymers with tunable chemical and physical properties, a new type of reactive polyphosphoester was synthesized bearing alkynyl groups by an organocatalyzed ring-opening polymerization, the chemical availability of the alkyne groups was investigated by employing "click" type azide-alkyne Huisgen cycloaddition and thiol-yne radical-mediated reactions. Based on this alkyne-functionalized polyphosphoester polymer and its two available "click" type reactions, two degradable nanoparticle systems were developed. To develop the first system, the well defined poly(ethylene oxide)-block-polyphosphester diblock copolymer was transformed into a multifunctional Paclitaxel drug

  5. Construction of conductive multilayer films of biogenic triangular gold nanoparticles and their application in chemical vapour sensing

    Science.gov (United States)

    Singh, Amit; Chaudhari, Minakshi; Sastry, Murali

    2006-05-01

    Metal nanoparticles are interesting building blocks for realizing films for a number of applications that include bio- and chemical sensing. To date, spherical metal nanoparticles have been used to generate functional electrical coatings. In this paper we demonstrate the synthesis of electrically conductive coatings using biologically prepared gold nanotriangles as the building blocks. The gold nanotriangles are prepared by the reduction of aqueous chloroaurate ions using an extract of the lemongrass plant (Cymbopogon flexuosus) which are thereafter assembled onto a variety of substrates by simple solution casting. The conductivity of the film shows a drastic fall upon mild heat treatment, leading to the formation of electrically conductive thin films of nanoparticles. We have also investigated the possibility of using the gold nanotriangle films in vapour sensing. A large fall in film resistance is observed upon exposure to polar molecules such as methanol, while little change occurs upon exposure to weakly polar molecules such as chloroform.

  6. Surface chemical and biological characterization of flax fabrics modified with silver nanoparticles for biomedical applications

    International Nuclear Information System (INIS)

    Paladini, F.; Picca, R.A.; Sportelli, M.C.; Cioffi, N.; Sannino, A.; Pollini, M.

    2015-01-01

    Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications and wound healing. This work aims to investigate the surface chemical composition and biological properties of silver nanoparticle-modified flax substrates. Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution, by means of a large-scale apparatus. The silver-coated materials were characterized through X-ray Photoelectron Spectroscopy (XPS), to assess the surface elemental composition of the coatings, and the chemical speciation of both the substrate and the antibacterial nanophases. A detailed investigation of XPS high resolution regions outlined that silver is mainly present on nanophases' surface as Ag 2 O. Scanning electron microscopy and energy dispersive X-ray spectroscopy were also carried out, in order to visualize the distribution of silver particles on the fibers. The materials were also characterized from a biological point of view in terms of antibacterial capability and cytotoxicity. Agar diffusion tests and bacterial enumeration tests were performed on Gram positive and Gram negative bacteria, namely Staphylococcus aureus and Escherichia coli. In vitro cytotoxicity tests were performed through the extract method on murine fibroblasts in order to verify if the presence of the silver coating affected the cellular viability and proliferation. Durability of the coating was also assessed, thus confirming the successful scaling up of the process, which will be therefore available for large-scale production. - Highlights: • Silver nanophases are increasingly used as effective antibacterial agent for biomedical applications. • Silver coatings were deposited on textiles through the in situ photo-reduction of a silver solution. • Flax fabrics were characterized from a biological and surface chemical point of view. • Scaling up of the process was confirmed

  7. Gold nanoparticles on MoS2 layered crystal flakes

    International Nuclear Information System (INIS)

    Cao, Wei; Pankratov, Vladimir; Huttula, Marko; Shi, Xinying; Saukko, Sami; Huang, Zhongjia; Zhang, Meng

    2015-01-01

    Inorganic layered crystal MoS 2 is considered as one of the most promising and efficient semiconductor materials for future transistors, photoelectronics, and electrocatalysis. To boost MoS 2 -based material applications, one direction is to grow physically and chemically reactive nanoparticles onto MoS 2 . Here we report on a simple route to synthesis crystalized MoS 2 –Au complexes. The gold nanoparticles were grown on MoS 2 flakes through a wet method in the oxygen free environment at room temperature. Nanoparticles with diameters varying from 9 nm to 429 nm were controlled by the molar ratios of MoS 2 and HAuCl 4 precursors. MoS 2 host flakes keep intrinsic honeycomb layered structures and the Au nanoparticles cubic-center crystal microstructures. From product chemical states analysis, the synthesis was found driven by redox reactions between the sulphide and the chloroauric acid. Photoluminescence measurement showed that introducing Au nanoparticles onto MoS 2 stacks substantially prompted excitonic transitions of stacks, as an analogy for doping Si wafers with dopants. Such composites may have potential applications in wide ranges similar as the doped Si. - Highlights: • The Au nanoparticles were decorated on MoS 2 in oxygen free ambiences via a wet method. • The Au nanoparticles are size-controllable and crystalized. • Chemical reaction scheme was clarified. • The MoS 2 –Au complexes have strong photoluminescent properties

  8. Wet milling versus co-precipitation in magnetite ferrofluid preparation

    Directory of Open Access Journals (Sweden)

    Almásy László

    2015-01-01

    Full Text Available Various uses of ferrofluids for technical applications continuously raise the interest in improvement and optimization of preparation methods. This paper deals with preparation of finely granulated magnetite particles coated with oleic acid in hydrocarbon suspensions following either chemical co-precipitation from iron salt precursors or wet milling of micron size magnetite powder with the goal to compare the benefits and disadvantages of each method. Microstructural measurements showed that both methods gave similar magnetite particle size of 10-15 nm. Higher saturation magnetization was achieved for the wet-milled magnetite suspension compared to relatively rapid co-precipitation synthesis. Different efficacies of ferrophase incorporation into kerosene could be related to the different mechanisms of oleic acid bonding to nanoparticle surface. The comparative data show that wet milling represents a practicable alternative to the traditional co-precipitation since despite of longer processing time, chemicals impact on environment can be avoided as well as the remnant water in the final product.

  9. Effect of annealing on the structure of chemically synthesized SnO_2 nanoparticles

    International Nuclear Information System (INIS)

    Singh, Kulwinder; Kumar, Akshay; Kumar, Virender; Vij, Ankush; Kumari, Sudesh; Thakur, Anup

    2016-01-01

    Tin oxide (SnO_2) nanoparticles have been synthesized by co-precipitation method. The synthesized nanoparticles were characterized by X-ray diffraction (XRD) and Raman spectroscopy. XRD analysis confirmed the single phase formation of SnO_2 nanoparticles. The Raman shifts showed the typical feature of the tetragonal phase of the as-synthesized SnO_2 nanoparticles. At low annealing temperature, a strong distortion of the crystalline structure and high degree of agglomeration was observed. It is concluded that the crystallinity of SnO_2 nanoparticles improves with the increase in annealing temperature.

  10. Thermal decomposition study of manganese sulfide (MnS) nanoparticles

    Science.gov (United States)

    Tailor, Jiten P.; Khimani, Ankurkumar J.; Chaki, Sunil H.; Deshpande, M. P.

    2018-05-01

    The as-synthesized manganese sulfide (MnS) nanoparticles were used for the thermal study. The nanoparticles were synthesized by simple wet chemical route at ambient temperature. The photoelectron binding energy and chemical composition of MnS nanoparticles was analyzed by X-ray photoelectron spectroscopy (XPS). The thermogravimetric (TG), differential thermogravimetric (DTG) and differential thermal analysis (DTA) were carried out on the as-synthesized MnS nanoparticles. The thermocurves were recorded in inert N2 atmosphere in the temperature range of ambient to 1173 K. The heating rates employed were 5, 10, 15 and 20 K/min. The thermodynamic parameters like activation energy (Ea), enthalpy change (ΔH), entropy change (ΔS) and change in Gibbs free energy (ΔG) of as-synthesized MnS nanoparticles were determined using Kissinger method. The obtained XPS and thermal results are discussed.

  11. EVALUATION OF INHIBITORY MEASURES FOR FOOD SPOILER YEAST CANDIDA KRUSEI DURING FERMENTATION PROCESS BY CHEMICAL, BIOCHEMICAL AND NANOPARTICLE APPROACHES

    Directory of Open Access Journals (Sweden)

    Indrani Bhattacharya

    2016-06-01

    Full Text Available Screening of chemical, biochemical and biomolecule-nanoparticle methods for the inhibition of Candida krusei were evaluated without hampering the growth of dairy yeast Kluyveromyces marxianus. The effective inhibition was observed with the help of H2O2, Williopsis saturnus, at specific combination of pH and temperature (pH 5.0 and 40 °C and Ag-KT4561 nanoparticles among the various methods used. However, the most efficient inhibition was observed with Ag-KT4561 nanoparticles. In general H2O2 works best at pH range 4.0 to 10.0 and at temperature 30 °C or above. H2O2 concentration of 4000 ppm at 45 °C and pH 5.5 exhibited significant inhibition of C. krusei, while K. marxianus remains unaffected. But, when used with lyophilized supernatant of W. saturnus, 2400 ppm H2O2 was effective. Further, nanoparticle with silver was synthesized to reduce the quantity of killer protein and enhance the efficiency of protein. Complete inhibition of C. krusei was observed at 350 µM of synthesized silver nano-particle (AgNPs of the killer protein from W. saturnus, with little effect on K. marxianus concentration. A stability test confirms the effect of protein silver nanoparticles on C. krusei for more than 20 weeks without any change in pH and temperature. Thus, the nanoparticles could be potentially used for inhibition of C. krusei without affecting the growth of K. marxianus and the process could be run non-aseptically.

  12. Photoluminescence and magnetic properties of Fe-doped ZnS nano-particles synthesized by chemical co-precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Nie Eryong; Liu Donglai; Zhang Yunsen; Bai Xue; Yi Liang; Jin Yong; Jiao Zhifeng [School of Materials Science and Engineering, Sichuan University, Chengdu 610064, Sichuan (China); Sun Xiaosong, E-mail: sunxs@scu.edu.cn [School of Materials Science and Engineering, Sichuan University, Chengdu 610064, Sichuan (China)

    2011-08-15

    This paper is focusing on the synthesis of Zn{sub 1-x}Fe{sub x}S nano-particles with x = 0, 0.1 and 0.2 by chemical co-precipitation method, the prepared of which are characterized by XRD, EDS, TEM, PL, magnetization versus field behavior and M-T curve. In the XRD patterns, Zn{sub 1-x}Fe{sub x}S nano-particles are shown of cubic zinc blende structure, and the broadening diffraction peaks consistent with the small-size characteristic of nano-materials. The diameter of nano-particles is between 3.3 and 5.5 nm according to the HR-TEM images. The EDS data confirm the existence of Fe ions in Fe-doped ZnS nanoparticles. There we found that Fe-doping did not import new energy bands or defect states, but reduced the intensity of PL peaks. The magnetization versus field behaviors were illustrated by the M-H curves at both 5 K and 300 K, respectively, where no remanence or coercive force was observed. This phenomenon indicates that the Zn{sub 1-x}Fe{sub x}S (x = 0.1) nano-particles are superparamagnetic. The zero-field-cooled (ZFC) and field-cooled (FC) magnetization curves further reveal that the blocking temperature (T{sub B}) of the superparamagnetic behavior might be below 5 K.

  13. Rhombic Coulomb diamonds in a single-electron transistor based on an Au nanoparticle chemically anchored at both ends.

    Science.gov (United States)

    Azuma, Yasuo; Onuma, Yuto; Sakamoto, Masanori; Teranishi, Toshiharu; Majima, Yutaka

    2016-02-28

    Rhombic Coulomb diamonds are clearly observed in a chemically anchored Au nanoparticle single-electron transistor. The stability diagrams show stable Coulomb blockade phenomena and agree with the theoretical curve calculated using the orthodox model. The resistances and capacitances of the double-barrier tunneling junctions between the source electrode and the Au core (R1 and C1, respectively), and those between the Au core and the drain electrode (R2 and C2, respectively), are evaluated as 4.5 MΩ, 1.4 aF, 4.8 MΩ, and 1.3 aF, respectively. This is determined by fitting the theoretical curve against the experimental Coulomb staircases. Two-methylene-group short octanedithiols (C8S2) in a C8S2/hexanethiol (C6S) mixed self-assembled monolayer is concluded to chemically anchor the core of the Au nanoparticle at both ends between the electroless-Au-plated nanogap electrodes even when the Au nanoparticle is protected by decanethiol (C10S). This is because the R1 value is identical to that of R2 and corresponds to the tunneling resistances of the octanedithiol chemically bonded with the Au core and the Au electrodes. The dependence of the Coulomb diamond shapes on the tunneling resistance ratio (R1/R2) is also discussed, especially in the case of the rhombic Coulomb diamonds. Rhombic Coulomb diamonds result from chemical anchoring of the core of the Au nanoparticle at both ends between the electroless-Au-plated nanogap electrodes.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-11-15

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

  15. Fundamentals of Hydrocarbon Upgrading to Liquid Fuels and Commodity Chemicals over Catalytic Metallic Nanoparticles

    Science.gov (United States)

    Chen, Tao

    Promising new technologies for biomass conversion into fuels and chemical feedstocks rely on the production of bio-oils, which need to be upgraded in order to remove oxygen-containing hydrocarbons and water. A high oxygen concentration makes bio-oils acidic and corrosive, unstable during storage, and less energetically valuable per unit weight than petroleum-derived hydrocarbons. Although there are efficient processes for the production of bio-oils, there are no efficient technologies for their upgrading. Current technologies utilize traditional petroleum refining catalysts, which are not optimized for biomass processing. New upgrading technologies are, therefore, urgently needed for development of sustainable energy resources. Development of such new technologies, however, is severely hindered by a lack of fundamental understanding of how oxygen and oxygen-containing hydrocarbons derived from biomass interact with promising noble-metal catalysts. In this study, kinetic reaction measurements, catalyst characterization and quantum chemical calculations using density functional theory were combined for determining adsorption modes and reaction mechanisms of hydrocarbons in the presence of oxygen on surfaces of catalytic noble-metal nanoparticles. The results were used for developing improved catalyst formulations and optimization of reaction conditions. The addition of molybdenum to platinum catalysts was shown to improve catalytic activity, stability, and selectivity in hydrodeoxygenation of acetic acid, which served as a model biomass compound. The fundamental results that describe interactions of oxygen and hydrocarbons with noble-metal catalysts were extended to other reactions and fields of study: evaluation of the reaction mechanism for hydrogen peroxide decomposition, development of improved hydrogenation catalysts and determination of adsorption modes of a spectroscopic probe molecule.

  16. Physico-chemical characterization of engineered metal oxide nanoparticles: the critical role of microscopy

    Science.gov (United States)

    La Fontaine, A.; Coleman, V. A.; Jämting, A. K.; Lawn, M.; Herrmann, J.; Miles, J. R.

    2010-06-01

    Three different methods for extracting zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles from commercially available sunscreen were investigated to determine the most appropriate route for producing a sample suitable for measuring the primary particle size. Direct dilution of the formulation, centrifugal methods and chemical washing were trialed in combination with ultrasonic processing and surfactant addition to generate samples that are suitable for particle size analysis. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used to monitor the extraction and re-dispersion process. Washing with hexane, methanol and water to remove the formulation, in combination with pulsed high-powered ultrasonication and the addition of a charge-stabilizing surfactant was found to be the most efficient way of producing de-agglomerated samples. DLS measurements gave average hydrodynamic particle diameters of 87 nm for ZnO and 76 nm for TiO2, compared to equivalent spherical particle diameters of 21 +/- 12 nm for ZnO (81 particles) and 19 +/- 14 nm for TiO2 (81 particles) obtained from TEM analysis.

  17. Raman scattering and band-gap variations of Al-doped ZnO nanoparticles synthesized by a chemical colloid process

    International Nuclear Information System (INIS)

    Lo, Shih-Shou; Huang, Dison; Tu, Chun Hsiang; Hou, Chia-Hung; Chen, Chii-Chang

    2009-01-01

    This study synthesizes Al-doped ZnO (AZO) nanoparticles using a chemical colloid process. Raman scattering analysis shows that Al doping increases the lattice defects and induces Raman vibration modes of 651 cm -1 . The Raman shift of the active mode E 2 (high) of AZO nanoparticles shows the presence and increase in the stress in nanoparticles when the Al dopant concentration increases. Room-temperature photoluminescence (RT-PL) spectra of synthesized AZO nanoparticles exhibit strong UV emissions near the band edges. The RT-PL peak shifts to a higher photon energy region as the Al concentration increases, indicating a broadening of the band gap.

  18. Chemical modification of magnetite nanoparticles and preparation of acrylic-base magnetic nanocomposite particles via miniemulsion polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Mahdieh, Athar; Mahdavian, Ali Reza, E-mail: a.mahdavian@ippi.ac.ir; Salehi-Mobarakeh, Hamid

    2017-03-15

    Nowadays, magnetic nanocomposite particles have attracted many interests because of their versatile applications. A new method for chemical modification of Fe{sub 3}O{sub 4} nanoparticles with polymerizable groups is presented here. After synthesis of Fe{sub 3}O{sub 4} nanoparticles by co-precipitation method, they were modified sequentially with 3-aminopropyl triethoxysilane (APTES), acryloyl chloride (AC) and benzoyl chloride (BC) and all were characterized by FTIR, XRD, SEM and TGA analyses. Then the modified magnetite nanoparticles with unsaturated acrylic groups were copolymerized with methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA) through miniemulsion polymerization. Although several reports exist on preparation of magnetite-base polymer particles, but the efficiency of magnetite encapsulationwith reasonable content and obtaining final stable latexes with limited aggregation ofFe{sub 3}O{sub 4} are still important issues. These were considered here by controlling reaction parameters. Hence, a seriesofmagneticnanocomposites latex particlescontaining different amounts of Fe{sub 3}O{sub 4} nanoparticles (0–10 wt%) were prepared with core-shell morphology and diameter below 200 nm and were characterized by FT-IR, DSC and TGA analyses. Their morphology and size distribution were studied by SEM, TEM and DLS analyses too. Magnetic properties of all products were also measuredby VSM analysis and the results revealed almost superparamagnetic properties for the obtained nanocomposite particles. - Highlights: • Chemical modification of magnetite nanoparticles. • Encapsulation of modified magnetite with acrylic copolymer. • Superparamagnetic Fe3O4/polyacrylic nanocomposite particles.

  19. Sensing colorimetric approaches based on gold and silver nanoparticles aggregation: Chemical creativity behind the assay. A review

    Energy Technology Data Exchange (ETDEWEB)

    Vilela, Diana; Gonzalez, Maria Cristina [Departamento de Quimica Analitica e Ingenieria Quimica, Facultad de Quimica, Edificio Polivalente, Universidad de Alcala, Ctra. Madrid-Barcelona km 33,600, 28871 Alcala de Henares, Madrid (Spain); Escarpa, Alberto, E-mail: alberto.escarpa@uah.es [Departamento de Quimica Analitica e Ingenieria Quimica, Facultad de Quimica, Edificio Polivalente, Universidad de Alcala, Ctra. Madrid-Barcelona km 33,600, 28871 Alcala de Henares, Madrid (Spain)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer Visual detection based gold and silver nanoparticles aggregation. Black-Right-Pointing-Pointer Functionalized and non-functionalized nanoparticles. Black-Right-Pointing-Pointer High selectivity and sensitivity. Black-Right-Pointing-Pointer No complex instrumentation is required/chemical creativity for analyte detection. - Abstract: Localized surface plasmon resonance (LSPR) is one of the most remarkable features of gold nanoparticles (Au NPs) and silver nanoparticles (Ag NPs). Due to these inherent optical properties, colloidal solutions of Au and Ag NPs have high extinction coefficients and different colour in the visible region of the spectrum when they are well-spaced in comparison with when they are aggregated. Therefore, a well-designed chemical interaction between the analyte and NPs surroundings leads to a change of colour (red to blue for Au NPs and yellow to brown for Ag NPs from well-spaced to aggregated ones, respectively) allowing the visual detection of the target analyte. These approaches have exhibited an excellent analytical performance with high sensitivities due to the strong LSPR and excellent selectivity strategically driven by the interaction analyte-NPs surroundings involving mainly electrostatic and hydrogen bond interactions as well as donor-acceptor chemical reactions, among others. In addition, this kind of colorimetric assays has received considerable attention in the analytical field because of their simplicity and low cost since they do not require any expensive or complex instrumentation. As a consequence of this, detection of molecules with a high significance in the bio-medical, clinical, food safety and environmental fields including DNA, proteins and a wide spectrum of organic molecules as well as inorganic ions have been impressively reported in the most relevant literature using these assays. This timely review offers a rational vision of the main achievements yielded in the relevant

  20. Sensing colorimetric approaches based on gold and silver nanoparticles aggregation: Chemical creativity behind the assay. A review

    International Nuclear Information System (INIS)

    Vilela, Diana; González, María Cristina; Escarpa, Alberto

    2012-01-01

    Highlights: ► Visual detection based gold and silver nanoparticles aggregation. ► Functionalized and non-functionalized nanoparticles. ► High selectivity and sensitivity. ► No complex instrumentation is required/chemical creativity for analyte detection. - Abstract: Localized surface plasmon resonance (LSPR) is one of the most remarkable features of gold nanoparticles (Au NPs) and silver nanoparticles (Ag NPs). Due to these inherent optical properties, colloidal solutions of Au and Ag NPs have high extinction coefficients and different colour in the visible region of the spectrum when they are well-spaced in comparison with when they are aggregated. Therefore, a well-designed chemical interaction between the analyte and NPs surroundings leads to a change of colour (red to blue for Au NPs and yellow to brown for Ag NPs from well-spaced to aggregated ones, respectively) allowing the visual detection of the target analyte. These approaches have exhibited an excellent analytical performance with high sensitivities due to the strong LSPR and excellent selectivity strategically driven by the interaction analyte-NPs surroundings involving mainly electrostatic and hydrogen bond interactions as well as donor–acceptor chemical reactions, among others. In addition, this kind of colorimetric assays has received considerable attention in the analytical field because of their simplicity and low cost since they do not require any expensive or complex instrumentation. As a consequence of this, detection of molecules with a high significance in the bio-medical, clinical, food safety and environmental fields including DNA, proteins and a wide spectrum of organic molecules as well as inorganic ions have been impressively reported in the most relevant literature using these assays. This timely review offers a rational vision of the main achievements yielded in the relevant literature according to this exciting and creative analytical field.

  1. Manufacturing Nanoparticles with Orthogonally Adjustable Dispersibility in Hydrocarbons, Fluorocarbons, and Water.

    Science.gov (United States)

    Zeininger, Lukas; Stiegler, Lisa M S; Portilla, Luis; Halik, Marcus; Hirsch, Andreas

    2018-04-01

    Invited for this month's cover picture is the group of Prof. Dr. Andreas Hirsch from Friedrich Alexander University (Germany). The cover picture shows shell-by-shell coated nanoparticle 'chameleons'-wet-chemically surface-modified nanoparticles that can reversibly adjust their dispersibility to entirely orthogonal solvent environments. Read the full text of their Full Paper at https://doi.org/10.1002/open.201800011.

  2. Film Formation of Ag Nanoparticles at the Organic-Aqueous Liquid Interface

    Science.gov (United States)

    Vigorita, John

    2005-03-01

    A wet-chemical method to make films by spontaneous assembly of passivated Ag nanoparticles at the organic-aqueous liquid interface is presented. The interfacial films exhibit a blue opalescence, or in other cases a silvery color, and are characterized with transmission electron microscopy and UV-visible spectrophotometry. Measurements indicate that nanoparticles in the interfacial film can form superlattices and in some cases nanostructures.

  3. nanoparticles

    Science.gov (United States)

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

    2014-10-01

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

  4. Magnetic core/shell nanoparticle thin films deposited by MAPLE: Investigation by chemical, morphological and in vitro biological assays

    International Nuclear Information System (INIS)

    Cristescu, R.; Popescu, C.; Socol, G.; Iordache, I.; Mihailescu, I.N.; Mihaiescu, D.E.; Grumezescu, A.M.; Balan, A.; Stamatin, I.; Chifiriuc, C.; Bleotu, C.; Saviuc, C.; Popa, M.; Chrisey, D.B.

    2012-01-01

    Highlights: ► We deposit magnetic Fe 3 O 4 /oleic acid/cephalosporin nanoparticle thin films by MAPLE. ► Thin films have a chemical structure similar to the starting material. ► Cephalosporins have an additive effect on the grain size and induce changes in grain shape. ► MAPLE can be used to develop novel strategies for fighting medical biofilms associated with chronic infections. - Abstract: We report on thin film deposition of nanostructured Fe 3 O 4 /oleic acid/ceftriaxone and Fe 3 O 4 /oleic acid/cefepime nanoparticles (core/shell/adsorption-shell) were fabricated by matrix assisted pulsed laser evaporation (MAPLE) onto inert substrates. The thin films were characterized by profilometry, Fourier transform infrared spectroscopy, atomic force microscopy, and investigated by in vitro biological assays. The biological properties tested included the investigation of the microbial viability and the microbial adherence to the glass coverslip nanoparticle film, using Gram-negative and Gram-positive bacterial strains with known antibiotic susceptibility behavior, the microbial adherence to the HeLa cells monolayer grown on the nanoparticle pellicle, and the cytotoxicity on eukaryotic cells. The proposed system, based on MAPLE, could be used for the development of novel anti-microbial materials or strategies for fighting pathogenic biofilms frequently implicated in the etiology of biofilm associated chronic infections.

  5. Investigating the Formation Process of Sn-Based Lead-Free Nanoparticles with a Chemical Reduction Method

    International Nuclear Information System (INIS)

    Zhang, W.; Zhao, B.; Gao, Y.; Zhang, W.; Zhao, B.; Zou, Ch.; Zhai, Q.; Gao, Y.; Gao, Y.; Acquah, S.F.A.

    2013-01-01

    Nanoparticles of a promising lead-free solder alloy (Sn 3.5 Ag (wt.%, Sn Ag) and Sn 3.0 Ag 0.5 Cu (wt.%, SAC)) were synthesized through a chemical reduction method by using anhydrous ethanol and 1,10-phenanthroline as the solvent and surfactant, respectively. To illustrate the formation process of Sn-Ag alloy based nanoparticles during the reaction, X-ray diffraction (XRD) was used to investigate the phases of the samples in relation to the reaction time. Different nucleation and growth mechanisms were compared on the formation process of the synthesized nanoparticles. The XRD results revealed different reaction process compared with other researchers. There were many contributing factors to the difference in the examples found in the literature, with the main focus on the formation mechanism of crystal nuclei, the solubility and ionizability of metal salts in the solvent, the solid solubility of Cu in Ag nuclei, and the role of surfactant on the growth process. This study will help define the parameters necessary for the control of both the composition and size of the nanoparticles

  6. Magnetic core/shell nanoparticle thin films deposited by MAPLE: Investigation by chemical, morphological and in vitro biological assays

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Popescu, C.; Socol, G.; Iordache, I.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Mihaiescu, D.E.; Grumezescu, A.M. [Faculty of Applied Chemistry and Materials Science, ' Politehnica' University of Bucharest, 1-7 Polizu Street, 011061 Bucharest (Romania); Balan, A.; Stamatin, I. [University of Bucharest, 3Nano-SAE Research Center, PO Box MG-38, Bucharest-Magurele (Romania); Chifiriuc, C. [Faculty of Biology, University of Bucharest, Microbiology Immunology Department, Aleea Portocalilor 1-3, Sector 5, 77206 Bucharest (Romania); Bleotu, C. [Stefan S. Nicolau Institute of Virology, 285 Mihai Bravu, 030304 Bucharest (Romania); Saviuc, C.; Popa, M. [Faculty of Biology, University of Bucharest, Microbiology Immunology Department, Aleea Portocalilor 1-3, Sector 5, 77206 Bucharest (Romania); Chrisey, D.B. [Rensselaer Polytechnic Institute, School of Engineering, Departments of Materials Science and Biomedical Engineering, Troy, 12180-3590, NY (United States)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer We deposit magnetic Fe{sub 3}O{sub 4}/oleic acid/cephalosporin nanoparticle thin films by MAPLE. Black-Right-Pointing-Pointer Thin films have a chemical structure similar to the starting material. Black-Right-Pointing-Pointer Cephalosporins have an additive effect on the grain size and induce changes in grain shape. Black-Right-Pointing-Pointer MAPLE can be used to develop novel strategies for fighting medical biofilms associated with chronic infections. - Abstract: We report on thin film deposition of nanostructured Fe{sub 3}O{sub 4}/oleic acid/ceftriaxone and Fe{sub 3}O{sub 4}/oleic acid/cefepime nanoparticles (core/shell/adsorption-shell) were fabricated by matrix assisted pulsed laser evaporation (MAPLE) onto inert substrates. The thin films were characterized by profilometry, Fourier transform infrared spectroscopy, atomic force microscopy, and investigated by in vitro biological assays. The biological properties tested included the investigation of the microbial viability and the microbial adherence to the glass coverslip nanoparticle film, using Gram-negative and Gram-positive bacterial strains with known antibiotic susceptibility behavior, the microbial adherence to the HeLa cells monolayer grown on the nanoparticle pellicle, and the cytotoxicity on eukaryotic cells. The proposed system, based on MAPLE, could be used for the development of novel anti-microbial materials or strategies for fighting pathogenic biofilms frequently implicated in the etiology of biofilm associated chronic infections.

  7. Nanoparticle/nanotube-based nanoelectronic devices and chemically-directed assembly thereof

    Science.gov (United States)

    Schmidt, Howard K [Cypress, TX

    2011-02-22

    According to some embodiments, the present invention provides a nanoelectronic device based on a nanostructure that may include a nanotube with first and second ends, a metallic nanoparticle attached to the first end, and an insulating nanoparticle attached to the second end. The nanoelectronic device may include additional nanostructures so a to form a plurality of nanostructures comprising the first nanostructure and the additional nanostructures. The plurality of nanostructures may arranged in a network comprising a plurality of edges and a plurality of vertices, wherein each edge comprises a nanotube and each vertex comprises at least one insulating nanoparticle and at least one metallic nanoparticle adjacent the insulating nanoparticle. The combination of at least one edge and at least one vertex comprises a diode. The device may be an optical rectenna.

  8. Thermo-chemical characterization of a Al nanoparticle and NiO nanowire composite modified by Cu powder

    International Nuclear Information System (INIS)

    Bohlouli-Zanjani, Golnaz; Wen, John Z.; Hu, Anming; Persic, John; Ringuette, Sophie; Zhou, Y. Norman

    2013-01-01

    Highlights: • First study on the copper modified powder-type Al nanoparticle and NiO nanowire composites. • Experimental findings were unique in identifying the AlNi formation and comparing with the Al/CuO thermite. • Potential applications in material joining and bonding. - Abstract: Thermo-chemical properties of the Al nanoparticle and NiO nanowire composites modified by the micro-sized copper additive were investigated experimentally. Their onset temperatures of ignition and energy release data per mass were characterized using differential thermal analysis measurements. These microstructures and chemical compositions of reaction products were analyzed using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. The fuel-rich Al/NiO/Cu composites produced two types of metallic spheres. Copper spheres were formed from melting and solidification of the copper additive, while AlNi composite spheres were identified by the energy dispersive X-ray spectroscopy and X-ray diffraction analyses. It was found that the amount of the copper additive did not significantly influence the onset temperature of thermite peaks, but caused a dramatic change in energy release. The aforementioned ignition and energetic properties were compared with these from the Al nanoparticle and CuO nanowire composites

  9. Electrodeposition of Nickel Nanoparticles for the Alkaline Hydrogen Evolution Reaction: Correlating Electrocatalytic Behavior and Chemical Composition.

    Science.gov (United States)

    Tao, Shasha; Yang, Florent; Schuch, Jona; Jaegermann, Wolfram; Kaiser, Bernhard

    2018-03-09

    Ni nanoparticles (NPs) consisting of Ni, NiO, and Ni(OH) 2 were formed on Ti substrates by electrodeposition as electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solution. Additionally, the deposition parameters including the potential range and the scan rate were varied, and the resulting NPs were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. The chemical composition of the NPs changed upon using different conditions, and it was found that the catalytic activity increased with an increase in the amount of NiO. From these data, optimized NPs were synthesized; the best sample showed an onset potential of approximately 0 V and an overpotential of 197 mV at a cathodic current density of 10 mA cm -2 as well as a small Tafel slope of 88 mV dec -1 in 1 m KOH, values that are comparable to those of Pt foil. These NPs consist of approximately 25 % Ni and Ni(OH) 2 each, as well as approximately 50 % NiO. This implies that to obtain a successful HER electrocatalyst, active sites with differing compositions have to be close to each other to promote the different reaction steps. Long-time measurements (30 h) showed almost complete transformation of the highly active catalyst compound consisting of Ni 0 , NiO, and Ni(OH) 2 into the less active Ni(OH) 2 phase. Nevertheless, the here-employed electrodeposition of nonprecious metal/metal-oxide combination compounds represents a promising alternative to Pt-based electrocatalysts for water reduction to hydrogen. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Chemically Regulated ROS Generation from Gold Nanoparticles for Enzyme-Free Electrochemiluminescent Immunosensing.

    Science.gov (United States)

    Higashi, Yui; Mazumder, Joyotu; Yoshikawa, Hiroyuki; Saito, Masato; Tamiya, Eiichi

    2018-04-17

    In the present work, we report on an enzyme-free electrochemiluminescent (ECL) immunosensing scheme utilizing the catalytic generation of reactive oxygen species (ROS) from gold nanoparticles (AuNPs) (diameter ≥5 nm) dispersed in aqueous solutions of trishydroxymethylaminomethane (Tris). First, to examine this catalytic pathway in detail, the effects of various factors such as the AuNP size and concentration, dispersant type and concentration, and dissolved oxygen were investigated using the electrochemiluminescence (ECL) of luminol. It was found that the catalytic generation of ROS from AuNPs can be regulated chemically by altering conditions such as the type, concentration, and pH of the solution that the AuNPs are dispersed in. Under the best conditions studied in this work, the AuNPs displayed high catalytic activity toward ROS generation, with an estimated apparent turnover number per AuNP of 0.1 s -1 , comparable to those of several common peroxide-producing enzymes. Following these studies, this phenomenon was applied to develop a one-step enzyme-free ECL immunosensor based on sandwiching the target analyte using antibody-conjugated magnetic beads (MB) and AuNPs. Using IgA as a model analyte, the developed immunosensor was able to detect the target in the range of 1 ng/mL to 10 μg/mL, with the lower detection limit being comparable to those of commercial assays for the same target. Altering the antibodies used to modify the MB and AuNPs could further improve the detection limit as well as expand the applicability of this immunoassay to the detection of other analytes.

  11. Assessing the physical-chemical properties and stability of dapivirine-loaded polymeric nanoparticles.

    Science.gov (United States)

    das Neves, José; Amiji, Mansoor; Bahia, Maria Fernanda; Sarmento, Bruno

    2013-11-18

    Nanocarriers may provide interesting delivery platforms for microbicide drugs and their characterization should be addressed early in development. Differently surface-engineered dapivirine-loaded, poly(epsilon-caprolactone) (PCL)-based nanoparticles (NPs) were obtained by nanoprecipitation using polyethylene oxide (PEO), sodium lauryl sulfate (SLS), or cetyltrimethylammonium bromide (CTAB) as surface modifiers. Physical-chemical properties of NP aqueous dispersions were evaluated upon storage at -20-40 °C for one year. NPs presented 170-200 nm in diameter, roundish-shape, low polydispersity index (≤0.18), and high drug association efficiency (≥97%) and loading (≥12.7%). NPs differed in zeta potential, depending on surface modifier (PEO: -27.9 mV; SLS: -54.7 mV; CTAB: +42.4 mV). No interactions among formulation components were detected by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR), except for SLS-PCL NPs. Colloidal properties of NPs were lost at -20 °C storage. Negatively charged NPs were stable up to one year at 5-40°C; as for CTAB-PCL NPs, particle aggregation was observed from 30 to 90 days of storage depending on temperature. Colloidal instability affected the in vitro drug release of CTAB-PCL NPs after 360 days. In any case, no degradation of dapivirine was apparent. Overall, PEO-PCL and SLS-PCL NPs presented suitable properties as nanocarriers for dapivirine. Conversely, CTAB-PCL NPs require additional strategies in order to increase stability. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Effects of para-substituents of styrene derivatives on their chemical reactivity on platinum nanoparticle surfaces

    Science.gov (United States)

    Hu, Peiguang; Chen, Limei; Deming, Christopher P.; Lu, Jia-En; Bonny, Lewis W.; Chen, Shaowei

    2016-06-01

    Stable platinum nanoparticles were successfully prepared by the self-assembly of para-substituted styrene derivatives onto the platinum surfaces as a result of platinum-catalyzed dehydrogenation and transformation of the vinyl groups to the acetylene ones, forming platinum-vinylidene/-acetylide interfacial bonds. Transmission electron microscopic measurements showed that the nanoparticles were well dispersed without apparent aggregation, suggesting sufficient protection of the nanoparticles by the organic capping ligands, and the average core diameter was estimated to be 2.0 +/- 0.3 nm, 1.3 +/- 0.2 nm, and 1.1 +/- 0.2 nm for the nanoparticles capped with 4-tert-butylstyrene, 4-methoxystyrene, and 4-(trifluoromethyl)styrene, respectively, as a result of the decreasing rate of dehydrogenation with the increasing Taft (polar) constant of the para-substituents. Importantly, the resulting nanoparticles exhibited unique photoluminescence, where an increase of the Hammett constant of the para-substituents corresponded to a blue-shift of the photoluminescence emission, suggesting an enlargement of the HOMO-LUMO band gap of the nanoparticle-bound acetylene moieties. Furthermore, the resulting nanoparticles exhibited apparent electrocatalytic activity towards oxygen reduction in acidic media, with the best performance among the series of samples observed with the 4-tert-butylstyrene-capped nanoparticles due to an optimal combination of the nanoparticle core size and ligand effects on the bonding interactions between platinum and oxygen species.Stable platinum nanoparticles were successfully prepared by the self-assembly of para-substituted styrene derivatives onto the platinum surfaces as a result of platinum-catalyzed dehydrogenation and transformation of the vinyl groups to the acetylene ones, forming platinum-vinylidene/-acetylide interfacial bonds. Transmission electron microscopic measurements showed that the nanoparticles were well dispersed without apparent

  13. A Detailed Experimental and Theoretical Investigation on the Chemical and Physical Behavior of Gold Nanoparticles under X-ray Radiation

    Science.gov (United States)

    Cheng, Neal

    A detailed investigation into the interaction between highly ionizing x-ray radiation and nanomaterials was performed. To begin, a theoretical model of the interactions of the system was created as an attempt to understand the relationship between the nanomaterial and the radiation-generated species. The model spans from the physical regime (10-10 s), during which the chemical species generated from radiolytic cleavage of water diffuses and reacts. A combination of methods was used in the simulation: Monte Carlo, Brownian diffusion, and kinetic rate equations. Several experimental systems were created for the purpose of testing the radio-enhancing effects of nanomaterials and the validity of the model: Firstly, the effects of localized energy deposition by gold nanoparticles were examined in a system consisting of 3 nm gold nanoparticles conjugated to DNA. In this system, single-strand breaks on DNA were used to probe the spatial distribution of energy nanometers around the nanoparticle. A comparison of the local energy deposition by gold nanoparticles versus global energy deposition by water was examined using the model. An additional 150% in DNA strand breaks was observed at 100 mM Tris (2-Amino-2-hydroxymethyl-propane-1,3-diol, represents 5nm diffusion distance), yet according to the model, the energy deposition of 10 gold nanoparticles on a strand of DNA accounts for only an additional 20%. Several explanations were given, such as the different reactivity of radical at short distance, the cross-linking of multiple DNA to a single nanoparticle, and geometric configuration of DNA. Secondly, the effect of remote energy deposition was examined in a system consisting of gold nanotubules and free-floating DNA, containing a composition of 50 wt.% Au/50 wt.% H2O. There was no localized energy deposition due to non-conjugation and a maximum enhancement of 1400% was found at 10 mM Tris, which was inconsistent with the expected enhancement of ˜14000%. The result was

  14. The Chemical Composition and Structure of Supported Sulfated Zirconia with Regulated Size Nanoparticles

    Science.gov (United States)

    Kanazhevskiy, V. V.; Shmachkova, V. P.; Kotsarenko, N. S.; Kochubey, D. I.; Vedrine, J. C.

    2007-02-01

    A set of model skeletal isomerization catalysts — sulfated zirconia nanoparticles of controlled thickness anchored on different supports — was prepared using colloidal solutions of Zr salt on titania as support. The nanoparticles of zirconia (1-5 nm) are epitaxially connected to the support surface, with S/Zr ratio equals to 1.3-1.5. It was shown by EXAFS that nanoparticles of non-stoichiometric zirconium sulfate Zr(SO4)1+x, where xlayers as zirconium hydroxide undergoes sulfation followed by thermal treatment.

  15. Preparation of TiC/W core–shell structured powders by one-step activation and chemical reduction process

    International Nuclear Information System (INIS)

    Ding, Xiao-Yu; Luo, Lai-Ma; Huang, Li-Mei; Luo, Guang-Nan; Zhu, Xiao-Yong; Cheng, Ji-Gui; Wu, Yu-Cheng

    2015-01-01

    Highlights: • A novel wet chemical method was used to prepare TiC/W core–shell structure powders. • TiC nanoparticles were well-encapsulated by W shells. • TiC phase was present in the interior of tungsten grains. - Abstract: In the present study, one-step activation and chemical reduction process as a novel wet-chemical route was performed for the preparation of TiC/W core–shell structured ultra-fine powders. The XRD, FE-SEM, TEM and EDS results demonstrated that the as-synthesized powders are of high purity and uniform with a diameter of approximately 500 nm. It is also found that the TiC nanoparticles were well-encapsulated by W shells. Such a unique process suggests a new method for preparing X/W (X refers the water-insoluble nanoparticles) core–shell nanoparticles with different cores

  16. The study of structural and optical properties of (Eu, La, Sm) codoped ZnO nanoparticles via a chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Jihui; Zhang, Qi; Han, Qiang; Fang, Yue; Wang, Jiaying; Li, Xiuyan; Liu, Yanqing [Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping, 136000 (China); Wang, Dandan [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China); Yang, Jinghai, E-mail: jhyang1@jlnu.edu.cn [Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University, Siping, 136000 (China); Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, 130033 (China)

    2017-06-15

    The (Eu, La, Sm) ions were doped into ZnO nanoparticles by a chemical route, and the substitution of (Eu, La, Sm) for Zn{sup 2+} ions was proved by analytic techniques of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, transmission electron microscope (TEM), photoluminescence (PL) and UV–vis absorption spectroscopy. The results revealed that the codoping did not change the wurtzite structure of ZnO nanoparticles, but the diameter of the nanoparticles decreased with increasing the rare earth (RE) doping concentrations. The optical bandgaps calculated through UV–visible absorption spectroscopy were found to decrease from 3.26 to 3.14 eV with increasing the RE doping concentrations, which also proved by the slight shift of UV positions in PL spectra. The sharp red emissions located at 578.2, 590.1 and 615.7 nm were originated from the 4f-4f transitions in Eu{sup 3+} ions under excitation of 325 nm. And these red emissions of Eu{sup 3+} ions showed a strong correlation with the energy storage centers of oxygen vacancies in the samples which was introduced by the other RE ions of La{sup 3+} and Sm{sup 3+} codoping. - Highlights: • Doping of (Eu, La, Sm) ions into ZnO nanoparticles is realized by a chemical route. • Eu{sup 3+}-related red emissions from intra-4f follow a similar trend as broad defect emission. • Red emissions of Eu{sup 3+} enhance with RE codoping due to oxygen vacancies as energy storage centers. • The bandgap can be tuned by RE codoping, which shows a prospect for the visible utilization.

  17. Influence of TiO2 Nanoparticles on Growth, Chemical Constituents and Toxicity of Fennel Plant

    International Nuclear Information System (INIS)

    Khater, M.S.; Osman, Y.A.H.

    2015-01-01

    The present work is carried out to evaluate the effect of TiO 2 nanoparticles treatments on fennel (Feoniculum Vulgare Mill) plants. The plants were sprayed with different concentrations of TiO 2 nanoparticles 2, 4 and 6 ppm. In most cases, the tallest plants, the highest number of branches , the highest fruit yield per plant and the highest values of Pigments, Carbohydrates, Sugars nitrogen , phosphorus , potassium were obtained from the treatment of 6 ppm TiO 2 nanoparticles of fennel . Results showed that sprayed fennel plant with concentrations of TiO 2 nanoparticles 0, 2, 4 and 6 ppm is safe and enhanced chlorophyll synthesis and consequently enhanced photosynthesis

  18. One-pot production of copper ferrite nanoparticles using a chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, Naoki, E-mail: nnishida@rs.tus.ac.jp; Amagasa, Shota [Tokyo University of Science, Department of Chemistry (Japan); Kobayashi, Yoshio [The University of Electro-Communications, Department of Engineering Science (Japan); Yamada, Yasuhiro [Tokyo University of Science, Department of Chemistry (Japan)

    2016-12-15

    Copper ferrite nanoparticles were synthesized via the oxidation of precipitates obtained from the reaction of FeCl{sub 2}, CuSO{sub 4} and N{sub 2}H{sub 4} in the presence of gelatin. These copper ferrite particles were subsequently examined using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and Mössbauer spectroscopy. The average size of the copper ferrite nanoparticles was less than 5 nm, and they exhibited superparamagnetic behavior as a result of their small size. The low temperature Mössbauer spectrum exhibited three sets of sextets, two corresponding to the tetrahedral and octahedral sites of the copper spinel structure and one with small hyperfine magnetic field corresponding to the surface or defects of the nanoparticles. When the ratio of copper salt was increased, the tetrahedral site became preferable for copper, and metallic copper and copper ferrite were both present in a single nanoparticle.

  19. Gold nanoparticle catalyzed oxidation of alcohols - From biomass to commodity chemicals

    DEFF Research Database (Denmark)

    Taarning, Esben; Christensen, Claus H.

    2007-01-01

    and glycerol are rich in alcohol functionalities. Thus, a key step in utilizing these resources lies in the conversion of this functional group. Benign oxidations involving oxygen as the stoichiometric oxidant are important from both an environmental and economical perspective. Recently, it has become clear...... that supported gold nanoparticles are highly active catalysts for oxidizing alcohols and aldehydes using oxygen as the oxidant. This perspective will focus on the use of gold nanoparticles in the oxidation of renewables....

  20. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  1. Introduction to wetting phenomena

    International Nuclear Information System (INIS)

    Indekeu, J.O.

    1995-01-01

    In these lectures the field of wetting phenomena is introduced from the point of view of statistical physics. The phase transition from partial to complete wetting is discussed and examples of relevant experiments in binary liquid mixtures are given. Cahn's concept of critical-point wetting is examined in detail. Finally, a connection is drawn between wetting near bulk criticality and the universality classes of surface critical phenomena. (author)

  2. Influence of chemical disorder on the electronic level spacing distribution of the Ag{sub 5083} nanoparticle: A tight-binding study

    Energy Technology Data Exchange (ETDEWEB)

    Medrano, L.R., E-mail: leonardoms20@gmail.com [Faculty of Physical Sciences, National University of San Marcos, P.O. Box 14-0149, Lima 14 (Peru); Landauro, C.V., E-mail: clandauros@unmsm.edu.pe [Faculty of Physical Sciences, National University of San Marcos, P.O. Box 14-0149, Lima 14 (Peru)

    2013-03-01

    In the present work we study, employing a tight-binding Hamiltonian, the influence of chemical disorder on the electronic level spacing distribution of a silver nanoparticle containing 5083 atoms (∼ 5.5 nm). This nanoparticle was obtained by molecular dynamics simulations with a tight-binding atomic potential. The results indicate that in the absence of disorder the level spacing distributions are similar to those expected for systems belonging to the Gaussian Orthogonal Ensemble. Whereas, after increasing the chemical disorder, the electronic level spacing distribution and the Σ{sub 2} statistics tend to the corresponding form for the Poisson Ensemble, i.e., the silver nanoparticle acquires an insulating character which is expected for strongly disordered systems. Hence, this kind of disorder produces the localization of the electronic states of the nanoparticle.

  3. Controlled fabrication of the strong emission YVO4:Eu3+ nanoparticles and nanowires by microwave assisted chemical synthesis

    International Nuclear Information System (INIS)

    Huong, Tran Thu; Vinh, Le Thi; Phuong, Ha Thi; Khuyen, Hoang Thi; Anh, Tran Kim; Tu, Vu Duc; Minh, Le Quoc

    2016-01-01

    In this report, we are presenting the controlled fabrication results of the strong emission YVO 4 : Eu 3+ nanoparticles and nanowires by microwave which is assisted chemical synthesis. The effects of incorporated synthesis conditions such as microwave irradiated powers, pH values and concentration of chemical composition on properties of nanomaterials are also investigated to obtain the controllable size and homogenous morphology. Morphological and optical properties of YVO 4 : Eu 3+ prepared products which have been characterized by X-ray diffraction (XRD), field emission micrcroscopy (FESEM) and photoluminescence spectroscopy. As based from result of synthesized samples, we found that the changing of pH values, microwave irradiated powers and chemical composition rise to change reform the size and shape of materials from nanoparticles (diameter about 20 nm) to wires shape (with about 500÷800 nm length and 10÷20 nm width). The photoluminescence (PL) spectroscopy measurements of YVO 4 : Eu 3+ nanostructure materials under UV excitation showed that: the strong luminescence in red region with narrow lines corresponding to the intra-4f transitions of 5 D 0 – 7 F j (j=1, 2, 3, and 4) of Eu 3+ ions with the highest luminescence intensity of 5 D 0 → 7 F 2 transition. - Highlights: • The strong emission YVO 4 :Eu 3+ nanostructure materials were successfully synthesized by microwave assisted chemical synthesis. • The size, morphology and luminescence of the YVO 4 :Eu 3+ nanostructure materials can be controlled by the solution pH, microwave irradiated powers and chemical composition. • These YVO 4 :Eu 3+ nanostructure materials above can potentially applied in various fields of application, especially in luminescent labeling and visualization in biomedical application.

  4. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Daanen, H.A.M.; Kappers, A.M.L.

    2011-01-01

    The sensation of wetness is well-known but barely investigated. There are no specific wetness receptors in the skin, but the sensation is mediated by temperature and pressure perception. In our study, we have measured discrimination thresholds for the haptic perception of wetness of three di erent

  5. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Dolfine Kosters, N.; Daanen, h.a.m.; Kappers, A.M.L.

    2012-01-01

    In daily life, people interact with textiles of different degrees of wetness, but little is known about the me-chanics of wetness perception. This paper describes an experiment with six conditions regarding haptic dis-crimination of the wetness of fabrics. Three materials were used: cotton wool,

  6. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Kappers, Astrid M.L.; Daanen, H.A.M.

    2012-01-01

    In daily life, people interact with textiles of different degrees of wetness, but little is known about the mechanics of wetness perception. This paper describes an experiment with six conditions regarding haptic discrimination of the wetness of fabrics. Three materials were used: cotton wool,

  7. Synthesis and characterization of ZrO2-CuO co-doped ceria nanoparticles via chemical precipitation method.

    Science.gov (United States)

    Viruthagiri, G; Gopinathan, E; Shanmugam, N; Gobi, R

    2014-10-15

    In the present study, the fluorite cubic phase of bare and ZrO2-CuO co-doped ceria (CeO2) nanoparticles have been synthesized through a simple chemical precipitation method. X-ray diffraction results revealed that average grain sizes of the samples are within 5-6nm range. The functional groups present in the samples were identified by Fourier Transform Infrared Spectroscopy (FTIR) study. Surface area measurement was carried out for the ceria nanoparticles to characterize the surface properties of the synthesized samples. The direct optical cutoff wavelength from DRS analysis was blue-shifted evidently with respect to the bulk material and indicated quantum-size confinement effect in the nanocrystallites. PL spectra revealed the strong and sharp UV emission at 401nm. The surface morphology and the element constitution of the pure and doped nanoparticles were studied by scanning electron microscope fitted with energy dispersive X-ray spectrometer arrangement. The thermal decomposition course was followed using thermo gravimetric and differential thermal analyses (TG-DTA). Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Growth graphene on silver-copper nanoparticles by chemical vapor deposition for high-performance surface-enhanced Raman scattering

    Science.gov (United States)

    Zhang, Xiumei; Xu, Shicai; Jiang, Shouzhen; Wang, Jihua; Wei, Jie; Xu, Shida; Gao, Shoubao; Liu, Hanping; Qiu, Hengwei; Li, Zhen; Liu, Huilan; Li, Zhenhua; Li, Hongsheng

    2015-10-01

    We present a graphene/silver-copper nanoparticle hybrid system (G/SCNPs) to be used as a high-performance surface-enhanced Raman scattering (SERS) substrate. The silver-copper nanoparticles wrapped by a monolayer graphene layer are directly synthesized on SiO2/Si substrate by chemical vapor deposition in a mixture of methane and hydrogen. The G/SCNPs shows excellent SERS enhancement activity and high reproducibility. The minimum detected concentration of R6G is as low as 10-10 M and the calibration curve shows a good linear response from 10-6 to 10-10 M. The date fluctuations from 20 positions of one SERS substrate are less than 8% and from 20 different substrates are less than 10%. The high reproducibility of the enhanced Raman signals could be due to the presence of an ultrathin graphene layer and uniform morphology of silver-copper nanoparticles. The use of G/SCNPs for detection of nucleosides extracted from human urine demonstrates great potential for the practical applications on a variety of detection in medicine and biotechnology field.

  9. Microporous Ni@NiO nanoparticles prepared by chemically dealloying Al_3Ni_2@Al nanoparticles as a high microwave absorption material

    International Nuclear Information System (INIS)

    Pang, Yu; Xie, Xiubo; Li, Da; Chou, Wusheng; Liu, Tong

    2017-01-01

    The Al_3Ni_2@Al nanoparticles (NPs) were prepared from Ni_4_5Al_5_5 master alloy by hydrogen plasma-metal reaction method, and were subsequently dealloyed to produce porous Ni@NiO NPs of 36 nm. The pore size ranges from 0.7 to 1.6 nm, leading to large specific surface area of 69.5 m"2/g and big pore volume of 0.507 cc/g. The saturation magnetization (M_S) and coercivity (H_C) of the microporous Ni@NiO NPs are 11.5 emu/g and 5.2 Oe. They exhibit high microwave absorption performance with a minimum reflection coefficient (RC) of −86.9 dB and an absorption bandwidth of 2.6 GHz (RC≤−10 dB) at thickness of 4.5 mm. The enhanced microwave absorption properties are attributed to the synergistic effect of the magnetic Ni core and dielectric NiO shell, and the micropore architecture. The NPs with micropore morphology and core/shell structure open a new way to modify the microwave absorption performance. - Graphical abstract: The microporous Ni/NiO nanoparticles prepared by chemically dealloying Al_3Ni_2@Al NPs exhibit high microwave absorption intensity (−86.9 dB) and wide absorption bandwidth (2.6 GHz for RC≤−10 dB). - Highlights: • Microporous Ni/NiO nanoparticals were prepared by chemically dealloying method. • They possessed micropores of 0.7–1.6 nm with a surface area of 69.5 m"2/g. • They showed high microwave absorption intensity and wide absorption bandwidth. • Microwave absorption mechanism was explained by micropore and core/shell structures.

  10. Microporous Ni@NiO nanoparticles prepared by chemically dealloying Al{sub 3}Ni{sub 2}@Al nanoparticles as a high microwave absorption material

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Yu; Xie, Xiubo; Li, Da [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, No.37 Xueyuan Road, Beijing 100191 (China); Chou, Wusheng [School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China); Liu, Tong, E-mail: tongliu@buaa.edu.cn [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, No.37 Xueyuan Road, Beijing 100191 (China)

    2017-03-15

    The Al{sub 3}Ni{sub 2}@Al nanoparticles (NPs) were prepared from Ni{sub 45}Al{sub 55} master alloy by hydrogen plasma-metal reaction method, and were subsequently dealloyed to produce porous Ni@NiO NPs of 36 nm. The pore size ranges from 0.7 to 1.6 nm, leading to large specific surface area of 69.5 m{sup 2}/g and big pore volume of 0.507 cc/g. The saturation magnetization (M{sub S}) and coercivity (H{sub C}) of the microporous Ni@NiO NPs are 11.5 emu/g and 5.2 Oe. They exhibit high microwave absorption performance with a minimum reflection coefficient (RC) of −86.9 dB and an absorption bandwidth of 2.6 GHz (RC≤−10 dB) at thickness of 4.5 mm. The enhanced microwave absorption properties are attributed to the synergistic effect of the magnetic Ni core and dielectric NiO shell, and the micropore architecture. The NPs with micropore morphology and core/shell structure open a new way to modify the microwave absorption performance. - Graphical abstract: The microporous Ni/NiO nanoparticles prepared by chemically dealloying Al{sub 3}Ni{sub 2}@Al NPs exhibit high microwave absorption intensity (−86.9 dB) and wide absorption bandwidth (2.6 GHz for RC≤−10 dB). - Highlights: • Microporous Ni/NiO nanoparticals were prepared by chemically dealloying method. • They possessed micropores of 0.7–1.6 nm with a surface area of 69.5 m{sup 2}/g. • They showed high microwave absorption intensity and wide absorption bandwidth. • Microwave absorption mechanism was explained by micropore and core/shell structures.

  11. Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngme [Ewha Womans University, College of Pharmacy (Korea, Republic of); Sah, Eric [University of Notre Dame, College of Science (United States); Sah, Hongkee, E-mail: hsah@ewha.ac.kr [Ewha Womans University, College of Pharmacy (Korea, Republic of)

    2015-11-15

    The objective of this study was to develop a new oil-in-water emulsion-based nanoencapsulation method for the preparation of PLGA nanoparticles using a non-halogenated solvent. PLGA (60–150 mg) was dissolved in 3 ml of methyl propionate, which was vortexed with 4 ml of a 0.5–4 % polyvinyl alcohol solution. This premix was sonicated for 2 min, added into 30 ml of the aqueous polyvinyl alcohol solution, and reacted with 3 ml of 10 N NaOH. Solvent removal was achieved by the alkaline hydrolysis of methyl propionate dissolved in an aqueous phase into water-soluble methanol and sodium propionate. It was a simple but effective technique to quickly harden nanoemulsion droplets into nanoparticles. The appearing PLGA nanoparticles were recovered by ultracentrifugation and/or dialysis, lyophilized with trehalose, and redispersed by water. This nanoencapsulation technique permitted a control of their mean diameters over 151.7 ± 3.8 to 440.2 ± 22.2 nm at mild processing conditions. When the aqueous polyvinyl alcohol concentration was set at ≥1 %, nanoparticles showed uniform distributions with polydispersity indices below 0.1. There were no significant changes in their mean diameters and size distribution patterns before and after lyophilization. When mestranol was encapsulated into nanoparticles, the drug was completely nanoencapsulated: depending on experimental conditions, their encapsulation efficiencies were determined to be 99.4 ± 7.2 to 105.8 ± 6.3 %. This simple, facile nanoencapsulation technique might have versatile applications for the preparation of polymeric nanoparticulate dosage forms.Graphical AbstractSchematic illustration of an innovative chemical approach to solvent removal during nanoencapsulation. Methyl propionate present in the aqueous continuous phase reacts with sodium hydroxide, thereby producing methanol and sodium propionate. Its alkaline hydrolysis allows the continuous extraction of the solvent out of nanoemulsion

  12. Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

    International Nuclear Information System (INIS)

    Lee, Youngme; Sah, Eric; Sah, Hongkee

    2015-01-01

    The objective of this study was to develop a new oil-in-water emulsion-based nanoencapsulation method for the preparation of PLGA nanoparticles using a non-halogenated solvent. PLGA (60–150 mg) was dissolved in 3 ml of methyl propionate, which was vortexed with 4 ml of a 0.5–4 % polyvinyl alcohol solution. This premix was sonicated for 2 min, added into 30 ml of the aqueous polyvinyl alcohol solution, and reacted with 3 ml of 10 N NaOH. Solvent removal was achieved by the alkaline hydrolysis of methyl propionate dissolved in an aqueous phase into water-soluble methanol and sodium propionate. It was a simple but effective technique to quickly harden nanoemulsion droplets into nanoparticles. The appearing PLGA nanoparticles were recovered by ultracentrifugation and/or dialysis, lyophilized with trehalose, and redispersed by water. This nanoencapsulation technique permitted a control of their mean diameters over 151.7 ± 3.8 to 440.2 ± 22.2 nm at mild processing conditions. When the aqueous polyvinyl alcohol concentration was set at ≥1 %, nanoparticles showed uniform distributions with polydispersity indices below 0.1. There were no significant changes in their mean diameters and size distribution patterns before and after lyophilization. When mestranol was encapsulated into nanoparticles, the drug was completely nanoencapsulated: depending on experimental conditions, their encapsulation efficiencies were determined to be 99.4 ± 7.2 to 105.8 ± 6.3 %. This simple, facile nanoencapsulation technique might have versatile applications for the preparation of polymeric nanoparticulate dosage forms.Graphical AbstractSchematic illustration of an innovative chemical approach to solvent removal during nanoencapsulation. Methyl propionate present in the aqueous continuous phase reacts with sodium hydroxide, thereby producing methanol and sodium propionate. Its alkaline hydrolysis allows the continuous extraction of the solvent out of nanoemulsion

  13. The Chemical Composition and Structure of Supported Sulfated Zirconia with Regulated Size Nanoparticles

    International Nuclear Information System (INIS)

    Kanazhevskiy, V. V.; Shmachkova, V. P.; Kotsarenko, N. S.; Kochubey, D. I.; Vedrine, J. C.

    2007-01-01

    A set of model skeletal isomerization catalysts - sulfated zirconia nanoparticles of controlled thickness anchored on different supports - was prepared using colloidal solutions of Zr salt on titania as support. The nanoparticles of zirconia (1-5 nm) are epitaxially connected to the support surface, with S/Zr ratio equals to 1.3-1.5. It was shown by EXAFS that nanoparticles of non-stoichiometric zirconium sulfate Zr(SO4)1+x, where x<0.5, are formed on the support surface. Its structure looks like half-period shifted counterdirected chains built-up by zirconium atoms linked by triangle pyramids of sulfate groups. Considering catalytic data of skeletal n-butane isomerisation at 150 deg. C, one can suggest that these species behave as the active component of sulfated zirconia. They are formed in subsurface layers as zirconium hydroxide undergoes sulfation followed by thermal treatment

  14. A new rapid chemical route to prepare reduced graphene oxide using copper metal nanoparticles

    International Nuclear Information System (INIS)

    Wu Tao; Gao Jianping; Xu Xiaoyang; Qiu Haixia; Wang Wei; Gao Chunjuan

    2013-01-01

    Copper metal nanoparticles were used as a reducing agent to reduce graphene oxide (GO). The reaction was complete in about 10 min and did not involve the use of any toxic reagents or acids that are typically used in the reduction of GO by Zn and Fe powders. The high reduction activity of the Cu nanoparticles, compared to Cu powder, may be the result of the formation of Cu 2 O nanoparticles. The effect of the mass ratio of the metal to GO for this reduction was also investigated. The reduction of the GO was verified by ultraviolet–visible absorption spectroscopy, x-ray diffraction, thermogravimetric analysis, Raman spectroscopy, x-ray photoelectron spectroscopy and transmission electron microscopy. After reduction, Cu 2 O supported on reduced GO was formed and showed superior catalytic ability for the degradation of a model dye pollutant, methylene blue. (paper)

  15. In-situ TEM visualization of vacancy injection and chemical partition during oxidation of Ni-Cr nanoparticles.

    Science.gov (United States)

    Wang, Chong-Min; Genc, Arda; Cheng, Huikai; Pullan, Lee; Baer, Donald R; Bruemmer, Stephen M

    2014-01-14

    Oxidation of alloy often involves chemical partition and injection of vacancies. Chemical partition is the consequence of selective oxidation, while injection of vacancies is associated with the differences of diffusivity of cations and anions. It is far from clear as how the injected vacancies behave during oxidation of metal. Using in-situ transmission electron microscopy, we captured unprecedented details on the collective behavior of injected vacancies during oxidation of metal, featuring an initial multi-site oxide nucleation, vacancy supersaturation, nucleation of a single cavity, sinking of vacancies into the cavity and accelerated oxidation of the particle. High sensitive energy dispersive x-ray spectroscopy mapping reveals that Cr is preferentially oxidized even at the initial oxidation, leading to a structure that Cr oxide is sandwiched near the inner wall of the hollow particle. The work provides a general guidance on tailoring of nanostructured materials involving multi-ion exchange such as core-shell structured composite nanoparticles.

  16. Exotic chemical arrangements and magnetic moment evolution of NixPt1-x (0 ≤x≤ 1) nanoparticles

    Science.gov (United States)

    Mokkath, Junais Habeeb

    2018-06-01

    We present a systematic study on the chemical ordering pattern and the magnetic properties of NixPt1-x (0 ⩽ x≤ 1) nanoparticles having a size of 1.5 nm by means of an approach which combines basin hopping structure sampling technique and spin-polarized density functional theory. We found exotic chemical ordering patterns for different Ni/Pt ratios. In addition, we observed a sharp phase transition from non-magnetic to ferromagnetic behaviour around x = 67%. We show that this is a direct consequence of a unique atomic arrangement on the surface in which Ni atoms club together causing the strong Ni-Ni magnetic interaction. The observed magnetic properties are correlated to the electronic density of states.

  17. Detection of chemical substances in water using an oxide nanowire transistor covered with a hydrophobic nanoparticle thin film as a liquid-vapour separation filter

    Directory of Open Access Journals (Sweden)

    Taekyung Lim

    2016-08-01

    Full Text Available We have developed a method to detect the presence of small amounts of chemical substances in water, using a Al2O3 nanoparticle thin film covered with phosphonic acid (HDF-PA self-assembled monolayer. The HDF-PA self-assembled Al2O3 nanoparticle thin film acts as a liquid-vapour separation filter, allowing the passage of chemical vapour while blocking liquids. Prevention of the liquid from contacting the SnO2 nanowire and source-drain electrodes is required in order to avoid abnormal operation. Using this characteristic, the concentration of chemical substances in water could be evaluated by measuring the current changes in the SnO2 nanowire transistor covered with the HDF-PA self-assembled Al2O3 nanoparticle thin film.

  18. Understanding the wetting properties of nanostructured selenium coatings: the role of nanostructured surface roughness and air-pocket formation

    Directory of Open Access Journals (Sweden)

    Tran PA

    2013-05-01

    Full Text Available Phong A Tran,1,2 Thomas J Webster31Department of Chemical and Biomolecular Engineering, University of Melbourne, Melbourne, VIC, Australia; 2The Particulate Fluid Processing Centre, University of Melbourne, Melbourne, VIC, Australia; 3Department of Chemical Engineering and Program in Bioengineering, Northeastern University, Boston, MA, USAAbstract: Wetting properties of biomaterials, in particular nanomaterials, play an important role, as these influence interactions with biological elements, such as proteins, bacteria, and cells. In this study, the wetting phenomenon of titanium substrates coated with selenium nanoparticles was studied using experimental and mathematical modeling tools. Importantly, these selenium-coated titanium substrates were previously reported to increase select protein adsorption (such as vitronectin and fibronectin, to decrease bacteria growth, and increase bone cell growth. Increased selenium nanoparticle coating density resulted in higher contact angles but remained within the hydrophilic regime. This trend was found in disagreement with the Wenzel model, which is widely used to understand the wetting properties of rough surfaces. The trend also did not fit well with the Cassie–Baxter model, which was developed to understand the wetting properties of composite surfaces. A modified wetting model was thus proposed in this study, to understand the contributing factors of material properties to the hydrophilicity/hydrophobicity of these nanostructured selenium-coated surfaces. The analysis and model created in this study can be useful in designing and/or understanding the wetting behavior of numerous biomedical materials and in turn, biological events (such as protein adsorption as well as bacteria and mammalian cell functions.Keywords: hydrophilicity, hydrophobicity, Wenzel model, Cassie–Baxter model, free energy, implant material, proteins, cells, bacteria

  19. Recent trends in the microwave-assisted synthesis of metal oxide nanoparticles supported on carbon nanotubes and their applications

    CSIR Research Space (South Africa)

    Motshekga, SC

    2012-01-01

    Full Text Available of these composites is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors. These techniques based on thermal heating can be time consuming and often lack control of particle size...

  20. Functionalized gold nanoparticle supported sensory mechanisms applied in detection of chemical and biological threat agents: A review

    International Nuclear Information System (INIS)

    Upadhyayula, Venkata K.K.

    2012-01-01

    Highlights: ► Smart sensors are needed for detection of chemical and biological threat agents. ► Smart sensors detect analytes with rapid speed, high sensitivity and selectivity. ► Functionalized gold nanoparticles (GNPs) can potentially smart sense threat agents. ► Functionalized GNPs support multiple analytical methods for sensing threat agents. ► Threat agents of all types can be detected using functionalized GNPs. - Abstract: There is a great necessity for development of novel sensory concepts supportive of smart sensing capabilities in defense and homeland security applications for detection of chemical and biological threat agents. A smart sensor is a detection device that can exhibit important features such as speed, sensitivity, selectivity, portability, and more importantly, simplicity in identifying a target analyte. Emerging nanomaterial based sensors, particularly those developed by utilizing functionalized gold nanoparticles (GNPs) as a sensing component potentially offer many desirable features needed for threat agent detection. The sensitiveness of physical properties expressed by GNPs, e.g. color, surface plasmon resonance, electrical conductivity and binding affinity are significantly enhanced when they are subjected to functionalization with an appropriate metal, organic or biomolecular functional groups. This sensitive nature of functionalized GNPs can be potentially exploited in the design of threat agent detection devices with smart sensing capabilities. In the presence of a target analyte (i.e., a chemical or biological threat agent) a change proportional to concentration of the analyte is observed, which can be measured either by colorimetric, fluorimetric, electrochemical or spectroscopic means. This article provides a review of how functionally modified gold colloids are applied in the detection of a broad range of threat agents, including radioactive substances, explosive compounds, chemical warfare agents, biotoxins, and

  1. Functionalized gold nanoparticle supported sensory mechanisms applied in detection of chemical and biological threat agents: A review

    Energy Technology Data Exchange (ETDEWEB)

    Upadhyayula, Venkata K.K., E-mail: Upadhyayula.Venkata@epa.gov [Oak Ridge Institute of Science and Education (ORISE), MC-100-44, PO Box 117, Oak Ridge, TN 37831 (United States)

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer Smart sensors are needed for detection of chemical and biological threat agents. Black-Right-Pointing-Pointer Smart sensors detect analytes with rapid speed, high sensitivity and selectivity. Black-Right-Pointing-Pointer Functionalized gold nanoparticles (GNPs) can potentially smart sense threat agents. Black-Right-Pointing-Pointer Functionalized GNPs support multiple analytical methods for sensing threat agents. Black-Right-Pointing-Pointer Threat agents of all types can be detected using functionalized GNPs. - Abstract: There is a great necessity for development of novel sensory concepts supportive of smart sensing capabilities in defense and homeland security applications for detection of chemical and biological threat agents. A smart sensor is a detection device that can exhibit important features such as speed, sensitivity, selectivity, portability, and more importantly, simplicity in identifying a target analyte. Emerging nanomaterial based sensors, particularly those developed by utilizing functionalized gold nanoparticles (GNPs) as a sensing component potentially offer many desirable features needed for threat agent detection. The sensitiveness of physical properties expressed by GNPs, e.g. color, surface plasmon resonance, electrical conductivity and binding affinity are significantly enhanced when they are subjected to functionalization with an appropriate metal, organic or biomolecular functional groups. This sensitive nature of functionalized GNPs can be potentially exploited in the design of threat agent detection devices with smart sensing capabilities. In the presence of a target analyte (i.e., a chemical or biological threat agent) a change proportional to concentration of the analyte is observed, which can be measured either by colorimetric, fluorimetric, electrochemical or spectroscopic means. This article provides a review of how functionally modified gold colloids are applied in the detection of a broad

  2. Facile method for the synthesis of gold nanoparticles using an ion coater

    Science.gov (United States)

    Lee, Seung Han; Jung, Hyun Kyu; Kim, Tae Cheol; Kim, Chang Hee; Shin, Chang Hwan; Yoon, Tae-Sik; Hong, A.-Ra; Jang, Ho Seong; Kim, Dong Hun

    2018-03-01

    Herein we report a metal nanoparticle synthesis method based on a physical vapor deposition process instead of the conventional wet process of chemical reactions in liquids. A narrow size distribution of synthesized gold nanoparticles was obtained using an ion coater on glycerin at low vapor pressure. The nanoparticle size could be modulated by controlling the sputtering conditions especially the discharge current. Due to the formation of gold nanoparticles, a surface plasmon resonance peak appeared at ∼530 nm in the absorption spectrum. The surface plasmon resonance peak exhibited red-shift with increasing size of the gold nanoparticles. Our results provide a simple, environmental friendly method for the synthesis of metal nanoparticles by combine low-cost deposition apparatus and a liquid medium, which is free from toxic reagents.

  3. Control of oil-wetting on technical textiles by means of photo-chemical surface modification and its relevance to the performance of compressed air filters

    International Nuclear Information System (INIS)

    Bahners, Thomas; Mölter-Siemens, Wolfgang; Haep, Stefan; Gutmann, Jochen S.

    2014-01-01

    Highlights: • The oil repellence of textile fabrics was increased following the Wenzel concept. • Fiber surfaces were micro-roughened by means of pulsed UV laser irradiation. • Subsequent UV-induced grafting yielded pronounced oil repellence. • The grafting process conserved the delicate topography of the fiber surfaces. • The modified fabrics showed favorable drainage behavior in oil droplet separation. - Abstract: A two-step process comprising a surface roughening step by excimer laser irradiation and a post-treatment by photo-grafting to decrease the surface free energy was employed to increase the oil repellence of technical fabrics made of poly(ethylene terephthalate) (PET). The modification was designed to improve the performance of multi-layer filters for compressed air filtration, in which the fabrics served to remove, i.e. drain, oil separated from the air stream. In detail, the fibers surfaces were roughened by applying several laser pulses at a wavelength of 248 nm and subsequently photo-grafted with 1H,1H,2H,2H-perfluoro-decyl acrylate (PPFDA). The oil wetting behavior was increased by the treatments from full wetting on the as-received fabrics to highly repellent with oil contact angles of (131 ± 7)°. On surfaces in the latter state, oil droplets did not spread or penetrate even after one day. The grafting of PPFDA alone without any surface roughening yielded an oil contact angle of (97 ± 11)°. However, the droplet completely penetrated the fabric over a period of one day. The drainage performance was characterized by recording the pressure drop over a two-layer model filter as a function of time. The results proved the potential of the treatment, which reduced the flow resistance after 1-h operation by approximately 25%

  4. Wet chemical preparation of YVO{sub 4}:Eu thin films as red-emitting phosphor layers for fully transparent flat dielectric discharge lamp

    Energy Technology Data Exchange (ETDEWEB)

    Klausch, A. [Institute for Inorganic Chemistry, Dresden University of Technology, Mommsenstr. 6, 01069 Dresden (Germany); Althues, H. [Fraunhofer Institute for Material and Beam Technology Winterbergstr. 28, 01309 Dresden (Germany); Freudenberg, T. [Leibniz Institute for Solid State and Materials Research, Helmholtzstrasse 20, 01069 Dresden (Germany); Kaskel, S., E-mail: Stefan.Kaskel@chemie.tu-dresden.de [Institute for Inorganic Chemistry, Dresden University of Technology, Mommsenstr. 6, 01069 Dresden (Germany)

    2012-04-30

    Highly transparent YVO{sub 4}:Eu thin films were deposited via dip coating of liquid nanoparticle dispersions on glass substrates. Annealing of the nanoparticle layers resulted in restructuring of the material into oriented crystalline films. The crystallinity was confirmed using powder X-ray diffraction. Film thickness was adjusted to 467 nm by multiple deposition. The resulting coatings show > 99% absorbance for wavelength below 300 nm and > 90% transmission in the visible spectral range. Under UV-light excitation a bright red photoluminescence with a quantum efficiency of 20% is observed. A planar, transparent dielectric barrier discharge lamp was constructed using YVO{sub 4}:Eu coated glasses and transparent electrodes made from antimony-doped tin dioxide thin films. - Highlights: Black-Right-Pointing-Pointer Preparation of highly transparent Eu{sup 3+} doped YVO{sub 4} phosphor thin films. Black-Right-Pointing-Pointer Improved crystallinity and optical properties through heat treatment. Black-Right-Pointing-Pointer Red emitting films on glass substrates were combined with antimony tin oxide thin films. Black-Right-Pointing-Pointer Fully transparent, planar gas discharge lamp as prototype for a light emitting window.

  5. A dewetting route to grow heterostructured nanoparticles based on thin film heterojunctions.

    Science.gov (United States)

    Li, Junjie; Yin, Deqiang; Li, Qiang; Chen, Chunlin; Huang, Sumei; Wang, Zhongchang

    2015-12-21

    Heterostructured nanoparticles have received considerable attention for their various applications due to their unique and tunable functionalities with respect to their individual bulk constituents. However, the current wet chemical synthesis of multicomponent heterostructured nanoparticles is rather complicated. Here, we report a simple and quick method to fabricate Co-Au dumbbell arrays by dewetting Co/Au heterojunctions on a Si substrate and demonstrate that the Co-Au dumbbells vary in size from 2 to 28 nm. We further show by chemical mapping that Co bells are covered by a pseudomorphic Au wetting layer of ∼4 Å, preventing the bells from oxidation. By controlling the thickness of metal heterojunctions and the annealing time, the morphology of the Co-Au nanoparticle is found to be transformed from the dumbbell to the core shell. This facile route is demonstrated to be useful for fabricating other metal-metal and metal-oxide heterostructures and hence holds technological promise for functional applications.

  6. The structural evolution and diffusion during the chemical transformation from cobalt to cobalt phosphide nanoparticles

    KAUST Repository

    Ha, Don-Hyung; Moreau, Liane M.; Bealing, Clive R.; Zhang, Haitao; Hennig, Richard G.; Robinson, Richard D.

    2011-01-01

    We report the structural evolution and the diffusion processes which occur during the phase transformation of nanoparticles (NPs), ε-Co to Co 2P to CoP, from a reaction with tri-n-octylphosphine (TOP). Extended X-ray absorption fine structure (EXAFS

  7. Optical and surface morphological properties of triethylamine passivated lead sulphide nanoparticles

    International Nuclear Information System (INIS)

    Navaneethan, M.; Nisha, K.D.; Ponnusamy, S.; Muthamizhchelvan, C.

    2009-01-01

    The triethylamine capped lead sulphide (PbS) nanoparticles were successfully synthesized by simple wet chemical method. The synthesized product has been characterized by powder X-ray diffraction (XRD), UV-vis spectrophotometry, FTIR spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and photoluminescence studies. The size of the PbS nanoparticles was determined from AFM, TEM, XRD and from these studies it is found that the size of the particles of the order of 10-15 nm. Significant 'blue shift' from bulk material was observed on the PbS nanoparticles using UV-vis and photoluminescence spectrum.

  8. PREFACE: Wetting: introductory note

    Science.gov (United States)

    Herminghaus, S.

    2005-03-01

    of very specific and quantitative predictions were put forward which were aimed at direct experimental tests of the developed concepts [9]. Experimentally, wetting phenomena proved to be a rather difficult field of research. While contact angles seem quite easy to measure, deeper insight can only be gained by assessing the physical properties of minute amounts of material, as provided by the molecularly thin wetting layers. At the same time, the variations in the chemical potential relevant for studying wetting transitions are very small, such that system stability sometimes poses hard to solve practical problems. As a consequence, layering transitions in cryogenic systems were among the first to be thoroughly studied [10] experimentally, since they require comparably moderate stability. First-order wetting transitions were not observed experimentally before the early nineties, either in (cryogenic) quantum systems [11,12] or in binary liquid mixtures [13,14]. The first observation of critical wetting, a continuous wetting transition, in 1996 [15] was a major breakthrough [16]. In the meantime, a detailed seminal paper by Pierre Gilles de Gennes published in 1985 [17] had spurred a large number of new research projects which were directed to wetting phenomena other than those related to phase transitions. More attention was paid to non-equilibrium physics, as it is at work when oil spreads over a surface, or a liquid coating beads off (`dewets') from its support and forms a pattern of many individual droplets. This turned out to be an extremely fruitful field of research, and was more readily complemented by experimental efforts than was the case with wetting transitions. It was encouraging to find effects analogous to layering (as mentioned above) in more common systems such as oil films spreading on a solid support [18,19]. Long standing riddles such as the divergence of dissipation at a moving contact line were now addressed both theoretically and experimentally

  9. Fluorine- and iron-modified hierarchical anatase microsphere photocatalyst for water cleaning: facile wet chemical synthesis and wavelength-sensitive photocatalytic reactivity.

    Science.gov (United States)

    Liu, Shaohong; Sun, Xudong; Li, Ji-Guang; Li, Xiaodong; Xiu, Zhimeng; Yang, He; Xue, Xiangxin

    2010-03-16

    High photocatalytic efficiency, easy recovery, and no biological toxicity are three key properties related to the practical application of anatase photocatalyst in water cleaning, but seem to be incompatible. Nanoparticles-constructed hierarchical anatase microspheres with high crystallinity and good dispersion prepared in this study via one-step solution processing at 90 degrees C under atmospheric pressure by using ammonium fluotitanate as the titanium source and urea as the precipitant can reconcile these three requirements. The hierarchical microspheres were found to grow via an aggregative mechanism, and contact recrystallization occurred at high additions of the FeCl(3) electrolyte into the reaction system. Simultaneous incorporation of fluorine and iron into the TiO(2) matrix was confirmed by combined analysis of X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV-vis absorption spectroscopy. Surface structure and morphology changes of the microspheres induced by high-temperature annealing were clearly observed by field-emission scanning electron microscopy, especially for the phase-transformed particles. The original nanoparticles-constructed rough surfaces partially became smooth, resulting in a sharp drop in photocatalytic efficiency. Interestingly, iron loading has detrimental effects on the visible-light photocatalytic activity of both the as-prepared and the postannealed anatase microspheres but greatly enhances the photocatalytic activity of the as-prepared anatase microspheres under UV irradiation. No matter under UV or visible-light irradiation, the fluorine-loaded anatase microspheres and especially the postannealed ones show excellent photocatalytic performance. The underlying mechanism of fluorine and iron loading on the photocatalytic efficacy of the anatase microspheres was discussed in detail. Beyond photocatalytic applications, this kind of material is of great importance to the assembling of

  10. Large-scale synthesis of monodisperse SiC nanoparticles with adjustable size, stoichiometric ratio and properties by fluidized bed chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rongzheng; Liu, Malin, E-mail: liumalin@tsinghua.edu.cn; Chang, Jiaxing [Tsinghua University, Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology (China)

    2017-02-15

    A facile fluidized bed chemical vapor deposition method was proposed for the synthesis of monodisperse SiC nanoparticles by using the single precursor of hexamethyldisilane (HMDS). SiC nanoparticles with average particle size from 10 to 200 nm were obtained by controlling the temperature and the gas ratio. An experimental chemical vapor deposition phase diagram of SiC in the HMDS-Ar-H{sub 2} system was obtained and three regions of SiC-Si, SiC and SiC-C can be distinguished. The BET surface area and the photoluminescence properties of the SiC nanoparticles can be adjusted by changing the nanoparticle size. For the SiC nanospheres with free carbon, a novel hierarchical structure with 5 ~ 8 nm SiC nanoparticles embedded into the graphite matrix was obtained. The advantages of fluidized bed technology for the preparation of SiC nanoparticles were proposed based on the features of homogenous reaction zone, narrow temperature distribution, ultra-short reactant residence time and mass production.

  11. Large-scale synthesis of monodisperse SiC nanoparticles with adjustable size, stoichiometric ratio and properties by fluidized bed chemical vapor deposition

    International Nuclear Information System (INIS)

    Liu, Rongzheng; Liu, Malin; Chang, Jiaxing

    2017-01-01

    A facile fluidized bed chemical vapor deposition method was proposed for the synthesis of monodisperse SiC nanoparticles by using the single precursor of hexamethyldisilane (HMDS). SiC nanoparticles with average particle size from 10 to 200 nm were obtained by controlling the temperature and the gas ratio. An experimental chemical vapor deposition phase diagram of SiC in the HMDS-Ar-H_2 system was obtained and three regions of SiC-Si, SiC and SiC-C can be distinguished. The BET surface area and the photoluminescence properties of the SiC nanoparticles can be adjusted by changing the nanoparticle size. For the SiC nanospheres with free carbon, a novel hierarchical structure with 5 ~ 8 nm SiC nanoparticles embedded into the graphite matrix was obtained. The advantages of fluidized bed technology for the preparation of SiC nanoparticles were proposed based on the features of homogenous reaction zone, narrow temperature distribution, ultra-short reactant residence time and mass production.

  12. Influence of Wetting and Mass Transfer Properties of Organic Chemical Mixtures in Vadose Zone Materials on Groundwater Contamination by Nonaqueous Phase Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Charles J Werth; Albert J Valocchi, Hongkyu Yoon

    2011-05-21

    Previous studies have found that organic acids, organic bases, and detergent-like chemicals change surface wettability. The wastewater and NAPL mixtures discharged at the Hanford site contain such chemicals, and their proportions likely change over time due to reaction-facilitated aging. The specific objectives of this work were to (1) determine the effect of organic chemical mixtures on surface wettability, (2) determine the effect of organic chemical mixtures on CCl4 volatilization rates from NAPL, and (3) accurately determine the migration, entrapment, and volatilization of organic chemical mixtures. Five tasks were proposed to achieve the project objectives. These are to (1) prepare representative batches of fresh and aged NAPL-wastewater mixtures, (2) to measure interfacial tension, contact angle, and capillary pressure-saturation profiles for the same mixtures, (3) to measure interphase mass transfer rates for the same mixtures using micromodels, (4) to measure multiphase flow and interphase mass transfer in large flow cell experiments, all using the same mixtures, and (5) to modify the multiphase flow simulator STOMP in order to account for updated P-S and interphase mass transfer relationships, and to simulate the impact of CCl4 in the vadose zone on groundwater contamination. Results and findings from these tasks and summarized in the attached final report.

  13. Chemical and structural properties of Pd nanoparticle-decorated graphene—Electron spectroscopic methods and QUASES

    Energy Technology Data Exchange (ETDEWEB)

    Lesiak, B., E-mail: blesiak-orlowska@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warszawa (Poland); Jiricek, P.; Bieloshapka, I. [Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 6, 162-53 Prague 6 (Czech Republic)

    2017-05-15

    Highlights: • Pd-decorated graphene oxide (GO), reduced graphene oxide (RGO), graphite (Gr). • Electron spectroscopy (XPS) aided with QUASES and REELS structural analysis. • Pd nanoparticle size decreases with surface hydrophilicity (oxygen group content). • PdO{sub x} overlayer thickness increases with surface hydrophilicity. • GO reduction, Pd decoration by reduction lead to exfoliated graphene structures. - Abstract: Graphite (Gr) and carbon nanomaterials such as graphene oxide (GO) and reduced graphene oxide (RGO) and those decorated with Pd nanoparticles were investigated by photoelectron spectroscopy (XPS) aided with Quantitative Analysis of Surfaces by Electron Spectroscopy (QUASES) and reflected electron energy loss spectroscopy (REELS). Oxidation of Gr decreased the C/O ratio from 10 (Gr) to 2.2 (GO), whereas reduction of GO by N{sub 2}H{sub 4} increased this ratio to 6.6 (RGO) due to decreasing number of oxygen groups (hydroxyl, epoxy, carbonyl and hydroxyl). Graphene materials and those after Pd decoration had 6–11 average number of layers in stacked nanostructures. Pd decoration using NaBH{sub 4}-reducing agents formed nanoparticles of size 6.9 nm (Pd/Gr) > 5.3 nm (Pd/RGO) > 4.25 nm (Pd/GO), with PdO{sub x} overlayer thickness of 2.20 nm (Pd/GO) > 1.42 nm (Pd/Gr) > 1.20 nm (Pd/RGO), decreased number of oxygen groups and average number of layers. Smaller Pd nanoparticles of larger PdO{sub x} overlayer thickness were observed on highly hydrophilic substrates (functional oxygen groups content). Decoration accompanied by reduction using NaBH{sub 4} led to the removal of water attached by hydrogen bonding to graphene interplanes and the formation of PdO{sub x} overlayer from oxygen functional groups. Nanoparticle size obtained from QUASES was confirmed by Pd 3d{sub 5/2} spectra binding energy and full-width at half maximum. Various chemistry and mechanisms of graphene reduction using N{sub 2}H{sub 4} and NaBH{sub 4} were observed, where Na

  14. A comparative study of the annealing behavior of Cu(In,Ga)(S,Se)2 based solar cells with an indium sulfide buffer layer, partly submitted to wet chemical treatments

    International Nuclear Information System (INIS)

    Hönes, C.; Hackenberg, J.; Zweigart, S.; Wachau, A.; Hergert, F.; Siebentritt, S.

    2015-01-01

    Indium sulfide thin films deposited via thermal evaporation from compound source material have been successfully utilized as a cadmium free buffer layer for Cu(In,Ga)Se 2 based solar cells. However, high efficiencies are only reached after an additional annealing step. In this work, the annealing behavior of Cu(In,Ga)(S,Se) 2 based indium sulfide buffered solar cells is compared to the annealing behavior of similar cells, which were submitted to wet chemical treatments partly containing cadmium ions. Upon annealing a significant improvement of the initial solar cell characteristics is observed for the untreated cell and is related to the increase of activation energy for the carrier recombination process and a decrease of the ideality factor within the one diode model. It is shown here that this improvement can also be achieved by wet treatments of the absorber prior to buffer layer deposition. Upon annealing these treated cells still gain in collection length but lose open circuit voltage, which is explained here within a model including a highly p-doped absorber surface layer and supported by simulations showing that a decrease in doping density of such a surface layer would lead to the observed effects

  15. A comparative study of the annealing behavior of Cu(In,Ga)(S,Se){sub 2} based solar cells with an indium sulfide buffer layer, partly submitted to wet chemical treatments

    Energy Technology Data Exchange (ETDEWEB)

    Hönes, C., E-mail: christian.hoenes@de.bosch.com [Corporate Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Straße 2, D-71701 Schwieberdingen (Germany); Laboratory for Photovoltaics, University of Luxembourg, 41 rue du Brill, L-4422 Belvaux (Luxembourg); Hackenberg, J. [Corporate Research and Advance Engineering, Robert Bosch GmbH, Robert-Bosch-Straße 2, D-71701 Schwieberdingen (Germany); Zweigart, S. [Corporate Research and Advance Engineering, Robert Bosch GmbH, Postfach 10 60 50, D-70049 Stuttgart (Germany); Wachau, A.; Hergert, F. [Bosch Solar CISTech GmbH, D-14772 Brandenburg (Germany); Siebentritt, S., E-mail: susanne.siebentritt@uni.lu [Laboratory for Photovoltaics, University of Luxembourg, 41 rue du Brill, L-4422 Belvaux (Luxembourg)

    2015-03-07

    Indium sulfide thin films deposited via thermal evaporation from compound source material have been successfully utilized as a cadmium free buffer layer for Cu(In,Ga)Se{sub 2} based solar cells. However, high efficiencies are only reached after an additional annealing step. In this work, the annealing behavior of Cu(In,Ga)(S,Se){sub 2} based indium sulfide buffered solar cells is compared to the annealing behavior of similar cells, which were submitted to wet chemical treatments partly containing cadmium ions. Upon annealing a significant improvement of the initial solar cell characteristics is observed for the untreated cell and is related to the increase of activation energy for the carrier recombination process and a decrease of the ideality factor within the one diode model. It is shown here that this improvement can also be achieved by wet treatments of the absorber prior to buffer layer deposition. Upon annealing these treated cells still gain in collection length but lose open circuit voltage, which is explained here within a model including a highly p-doped absorber surface layer and supported by simulations showing that a decrease in doping density of such a surface layer would lead to the observed effects.

  16. Wet Gas Airfoil Analyses

    OpenAIRE

    Larsen, Tarjei Thorrud

    2011-01-01

    Subsea wet gas compression renders new possibilities for cost savings and enhanced gas recovery on existing gas wells. Technology like this opens to make traditional offshore processing plants redundant. With new technology, follows new challenges. Multiphase flows is regarded as a complex field of study, and increased knowledge on the fundamental mechanisms regarding wet gas flow is of paramount importance to the efficiency and stability of the wet gas compressor. The scope of this work was ...

  17. Effects of wood polymers and extractives on the adsorption of wet-end chemicals and the properties of the sheet - MPKY 03

    Energy Technology Data Exchange (ETDEWEB)

    Bobacka, V; Lindholm, J; Nurmi, M; Naesman, J [Aabo Akademi, Turku (Finland). Lab. of Paper Chemistry; Holmbom, B; Konn, J; Sundberg, A; Willfoer, S [Aabo Akademi, Turku (Finland). Lab. of Forest Products Chemistry

    1999-12-31

    The effects of deposition of dissolved and colloidal substances (disco, DCS) together with fixing agents on the wet end chemistry, and the paper quality have been studied. Increased amounts of wood resin in handsheets results in lower strength properties and friction of the sheets. Addition of isolated polysaccharides together with wood resin results in higher strength properties compared, at the same resin content, to sheets without added polysaccharides. Disco substances released from TMP were adsorbed/deposited onto different fillers. It is possible to determine the distribution of aggregated wood resin in handsheets of kraft pulp by confocal laser scanning microscopy. Addition of iron salts to a TMP suspension results in a decrease in the brightness of the fibers. The adsorption of cationic starch and cationic polyacrylamide was studied as well as the flocculation of a peroxide bleached TMP and mixture of TMP and kraft pulp in the presence of retention aids and fixing agents. The fixing agent had a minor effect on the flocculation in peroxide bleached TMP, while cationic starch induced flocculation after a threshold. When added together, cationic starch induced flocculation immediately. The retention of carbohydrates in the mixture was not much influenced by the presence of fixing agents and retention aids, but the extractives were efficiently retained. Colloidal substances adsorb both cationic starch and polyacrylamide. Of the dissolved substances, pectic acids are most efficiently aggregated. (orig.)

  18. Effects of wood polymers and extractives on the adsorption of wet-end chemicals and the properties of the sheet - MPKY 03

    Energy Technology Data Exchange (ETDEWEB)

    Bobacka, V.; Lindholm, J.; Nurmi, M.; Naesman, J. [Aabo Akademi, Turku (Finland). Lab. of Paper Chemistry; Holmbom, B.; Konn, J.; Sundberg, A.; Willfoer, S. [Aabo Akademi, Turku (Finland). Lab. of Forest Products Chemistry

    1998-12-31

    The effects of deposition of dissolved and colloidal substances (disco, DCS) together with fixing agents on the wet end chemistry, and the paper quality have been studied. Increased amounts of wood resin in handsheets results in lower strength properties and friction of the sheets. Addition of isolated polysaccharides together with wood resin results in higher strength properties compared, at the same resin content, to sheets without added polysaccharides. Disco substances released from TMP were adsorbed/deposited onto different fillers. It is possible to determine the distribution of aggregated wood resin in handsheets of kraft pulp by confocal laser scanning microscopy. Addition of iron salts to a TMP suspension results in a decrease in the brightness of the fibers. The adsorption of cationic starch and cationic polyacrylamide was studied as well as the flocculation of a peroxide bleached TMP and mixture of TMP and kraft pulp in the presence of retention aids and fixing agents. The fixing agent had a minor effect on the flocculation in peroxide bleached TMP, while cationic starch induced flocculation after a threshold. When added together, cationic starch induced flocculation immediately. The retention of carbohydrates in the mixture was not much influenced by the presence of fixing agents and retention aids, but the extractives were efficiently retained. Colloidal substances adsorb both cationic starch and polyacrylamide. Of the dissolved substances, pectic acids are most efficiently aggregated. (orig.)

  19. Synthesis and characterization of polyethylene glycol (PEG) coated Fe3O4 nanoparticles by chemical co-precipitation method for biomedical applications.

    Science.gov (United States)

    Anbarasu, M; Anandan, M; Chinnasamy, E; Gopinath, V; Balamurugan, K

    2015-01-25

    Polyethylene glycol (PEG) coated Fe3O4 nanoparticles were synthesized by chemical co-precipitation method. With polyethylene glycol (PEG) as a stabilizer and dispersant. The X-ray diffraction and selected area electron diffraction (SAED) results show that the cubic inverse spinel structure of pure phase polycrystalline Fe3O4 was obtained. The scanning electron microscopy (SEM) and field emission transmission electron microscopy (FE-TEM) results exhibited that the resulted Fe3O4 nanoparticles were roughly spherical in shape with narrow size distribution and homogenous shape. Fourier transform infrared spectroscopy (FT-IR) results suggested that PEG indicated with Fe3O4 via its carbonyl groups. Results of vibrating sample magnetometer (VSM) indicated that the prepared Fe3O4 nanoparticles exhibit superparamagnetic behavior and high saturation magnetization at room temperature. Such Fe3O4 nanoparticles with favorable size and tunable magnetic properties are promising biomedical applications. Copyright © 2014. Published by Elsevier B.V.

  20. Size effect on L10 ordering and magnetic properties of chemically synthesized FePt and FePtAu nanoparticles

    Science.gov (United States)

    Jia, Zhiyong; Kang, Shishou; Shi, Shifan; Nikles, David E.; Harrell, J. W.

    2005-05-01

    There is growing evidence that FePt nanoparticles become increasingly difficult to chemically order as the size approaches a few nanometers. We have studied the chemical ordering of FePt and FePtAu nanoparticle arrays as a function of particle size. Monodisperse Fe49Pt51 and Fe48Pt44Au8 nanoparticles with a size about 6nm were synthesized by the simultaneous decomposition of iron pentacarbonyl and reduction of platinum acetylacetonate and gold (III) acetate in a mixture of phenyl ether and hexadecylamine (HDA), with 1-adamantanecarboxylic acid and HDA as stabilizers. The nanoparticles were dispersed in toluene, films of the particles were cast onto silicon wafers from the dispersion, and the films were annealed in a tube furnace with flowing Ar +5%H2. The magnetic anisotropy and switching volumes were determined from time- and temperature-dependent coercivity measurements. By comparing with 3-nm FePt and FePtAu nanoparticles of comparable composition, the phase transformation is easier for the larger particles. Under the same annealing conditions, the larger particles have higher anisotropy and order parameter. Additive Au is very effective in enhancing the chemical ordering in both small and large particles, with x-ray diffraction superlattice peaks appearing after annealing at 350°C. Dynamic remnant coercivity measurements and magnetic switching volumes suggest particle aggregation at the higher annealing temperatures in both small and large particles.

  1. Multivalent display of proteins on viral nanoparticles using molecular recognition and chemical ligation strategies

    Science.gov (United States)

    Venter, P. Arno; Dirksen, Anouk; Thomas, Diane; Manchester, Marianne; Dawson, Philip E.; Schneemann, Anette

    2011-01-01

    Multivalent display of heterologous proteins on viral nanoparticles forms a basis for numerous applications in nanotechnology, including vaccine development, targeted therapeutic delivery and tissue-specific bio-imaging. In many instances, precise placement of proteins is required for optimal functioning of the supramolecular assemblies, but orientation- and site-specific coupling of proteins to viral scaffolds remains a significant technical challenge. We have developed two strategies that allow for controlled attachment of a variety of proteins on viral particles using covalent and noncovalent principles. In one strategy, an interaction between domain 4 of anthrax protective antigen and its receptor was used to display multiple copies of a target protein on virus-like particles. In the other, expressed protein ligation and aniline-catalyzed oximation was used to covalently display a model protein. The latter strategy, in particular, yielded nanoparticles that induced potent immune responses to the coupled protein, suggesting potential applications in vaccine development. PMID:21545187

  2. Schiff Base Ligand Coated Gold Nanoparticles for the Chemical Sensing of Fe(III Ions

    Directory of Open Access Journals (Sweden)

    Abiola Azeez Jimoh

    2015-01-01

    Full Text Available New Schiff base-coated gold nanoparticles (AuNPs of type AuNP@L (where L: thiolated Schiff base ligand have been synthesized and characterized using various spectroscopic techniques. The AuNPs and AuNP@L were imaged by transmission electron microscopy (TEM and were confirmed to be well-dispersed, uniformly distributed, spherical nanoparticles with an average diameter of 8–10 nm. Their potential applications for chemosensing were investigated in UV-Vis and fluorescence spectroscopic studies. The AuNP@L exhibited selectivity for Fe3+ in an ethanol/water mixture (ratio 9 : 1 v/v. The absorption and emission spectral studies revealed a 1 : 1 binding mode for Fe3+, with binding constants of 8.5×105 and 2.9×105 M−1, respectively.

  3. IR laser-induced chemical vapor deposition of carbon-coated iron nanoparticles embeded in polymer

    Czech Academy of Sciences Publication Activity Database

    Díaz, L.; Santos, M.; Ballesteros, C.; Maryško, Miroslav; Pola, Josef

    2005-01-01

    Roč. 15, - (2005), s. 4311-4317 ISSN 0959-9428 R&D Projects: GA MŠk(CZ) ME 684 Grant - others:DGI, MCyT(ES) BQU2003-08531-C02-; CiCYT(ES) ESP -2002-04509-C04-01 Institutional research plan: CEZ:AV0Z10100521 Keywords : magnetic nanoparticles * polymers Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.688, year: 2005

  4. Growth of CdS nanoparticles by chemical method and its ...

    Indian Academy of Sciences (India)

    carbon film supported on the copper grid and was kept for some time for drying. Transmission electron ... Wang et al obtained CdS nanoparticles having a band gap of. 2.79 eV [21]. .... [16] S Yu, Y Wu, J Yang, Z Han, Y Quan, X Liu and Y Xie, Chem. Matter 10 ... [22] U K Gautam, R Seshadri and C N R Rao, Chem. Phys. Lett.

  5. Magnetoconductive maghemite core/polyaniline shell nanoparticles: physico-chemical and biological assessment

    Czech Academy of Sciences Publication Activity Database

    Zasońska, Beata Anna; Bober, Patrycja; Jošt, P.; Petrovský, Eduard; Boštík, P.; Horák, Daniel

    2016-01-01

    Roč. 141, 1 May (2016), s. 382-389 ISSN 0927-7765 R&D Projects: GA MŠk(CZ) LH14318; GA ČR(CZ) GP14-05568P; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:67985530 Keywords : maghemite * nanoparticles * core–shell Subject RIV: CD - Macromolecular Chemistry; DE - Earth Magnetism, Geodesy, Geography (GFU-E) Impact factor: 3.887, year: 2016

  6. The anomalous physical and chemical properties of gold nano-particles

    International Nuclear Information System (INIS)

    Cortie, M.B.

    2003-01-01

    Full text: Although gold is the most inert of all metallic elements, it has been discovered during the last two decades that it has interesting properties as a nano-particle. Some of the properties of interest include its activity as a heterogeneous catalyst, particularly at low temperatures, its optical properties, and the tendency of its nano-particles to adopt non-crystallographic structures. There are a number of curious aspects to catalysis by gold that are attracting academic and industrial investigation and much is still not understood about the mechanism by which they work. For example, apparently similar preparation techniques result in activities of hugely varying magnitude. In the present talk I assess the what is known about gold nano-particles, with particular reference to their physical, electronic, crystallographic and catalytic properties. It is shown that there is much evidence in favour of the belief that it is the unique electronic structure of these particles that imbues them with catalytic activity. If this is true then tighter control of the electronic structure would allow for the design of more specific and more active catalysts

  7. A novel nano-hydroxyapatite — PMMA hybrid scaffolds adopted by conjugated thermal induced phase separation (TIPS) and wet-chemical approach: Analysis of its mechanical and biological properties

    Energy Technology Data Exchange (ETDEWEB)

    G, Radha [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy Campus, Chennai 600025 (India); S, Balakumar, E-mail: balasuga@yahoo.com [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy Campus, Chennai 600025 (India); Venkatesan, Balaji; Vellaichamy, Elangovan [Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600025 (India)

    2017-06-01

    In this study, we report the preparation of nano-hydroxyapatite (nHAp) incorporated poly(methyl methacrylate) (PMMA) scaffolds by conjugated thermal induced phase separation (TIPS) and wet-chemical approach, which essentially facilitates the enhancement of both mechanical as well as biological properties of the scaffolds. The dissolution of PMMA was accomplished by acetone (Ace scaffold), ethanol-water (E-W scaffold) and isopropanol-water (I-W scaffold) mixtures as solvents. The existence of nHAp in PMMA matrix was investigated systematically. The higher degree of porous architecture was achieved from Ace scaffolds compared to both I-W and E-W scaffolds. On the other hand, the dense porous architecture of the I-W scaffold exhibited superior hardness and compressive strength than that of the Ace and E-W scaffolds. All the fabricated samples demonstrated enhanced in vitro bioactivity with respect to increasing immersion period as a result of flower-like in vitro apatite layer formation. The MTT assay was carried out for 1 day and 3 day culture using Saos-2 osteoblast-like cells, which showed better cell proliferation with increasing culture period owing to the interconnected pore architecture of scaffolds and the rational hemocompatibility as per the ASTM standard F756-00. - Highlights: • Conjugated TIPS – wet chemical derived strategy was adopted for PMMA-nHAp composite scaffolds preparation. • TIPS method was carried out by varying solvents such as acetone, isopropanol-water and ethanol-water mixtures. • The impact of solvents on porosity and mechanical properties has been explored. • The existence of nHAp in PMMA has improved in-vitro bioactivity through apatitic-flowers formation. • Hemocompatibility of the scaffolds are in agreement with ASTM standards.

  8. A novel nano-hydroxyapatite – PMMA hybrid scaffolds adopted by conjugated thermal induced phase separation (TIPS) and wet-chemical approach: Analysis of its mechanical and biological properties

    Energy Technology Data Exchange (ETDEWEB)

    Radha, G. [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy campus, Chennai 600025 (India); Balakumar, S., E-mail: balasuga@yahoo.com [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy campus, Chennai 600025 (India); Venkatesan, Balaji; Vellaichamy, Elangovan [Department of Biochemistry, University of Madras, Guindy campus, Chennai 600025 (India)

    2017-04-01

    In this study, we report the preparation of nano-hydroxyapatite (nHAp) incorporated poly(methyl methacrylate) (PMMA) scaffolds by conjugated thermal induced phase separation (TIPS) and wet-chemical approach, which essentially facilitates the enhancement of both mechanical as well as biological properties of the scaffolds. The dissolution of PMMA was accomplished by acetone (Ace scaffold), ethanol-water (E-W scaffold) and isopropanol-water (I-W scaffold) mixtures as solvents. The existence of nHAp in PMMA matrix was investigated systematically. The porosity of ~ 57.89% was achieved from Ace scaffold that was higher degree compared to both I-W and E-W scaffolds. On the other hand, the dense porous architecture of I-W scaffold exhibited superior hardness of ~ 65.6 HR ‘D’ than that of the Ace and E-W scaffolds. All the fabricated samples demonstrated enhanced in vitro bioactivity with respect to increasing immersion period as a result of flower-like in vitro apatite layer formation. The MTT assay was carried out for 1 day and 3 day culture using Saos-2 osteoblast-like cells, which showed better cell proliferation with increasing culture period owing to the interconnected pore architecture of scaffolds and the rational hemocompatibility as per the ASTM standard F756-00. - Highlights: • Conjugated TIPS – wet chemical derived strategy was adopted for PMMA-nHAp composite scaffolds preparation. • TIPS method was carried out by varying solvents such as acetone, isopropanol-water and ethanol-water mixtures. • The impact of solvents on porosity and mechanical properties has been explored. • The existence of nHAp in PMMA has improved in-vitro bioactivity through apatitic-flowers formation. • Hemocompatibility of the scaffolds are in agreement with ASTM standards.

  9. Using chemical wet-etching methods of textured AZO films on a-Si:H solar cells for efficient light trapping

    International Nuclear Information System (INIS)

    Lin, Guo-Sheng; Li, Chien-Yu; Huang, Kuo-Chan; Houng, Mau-Phon

    2015-01-01

    In this paper, Al-doped ZnO (AZO) films are deposited on glasses substrate by RF magnetron sputtering. The optical, electrical and morphological properties of AZO films textured by wet-etching with different etchants, H 3 PO 4 , HCl, and HNO 3 are studied. It is found that the textured structure could enhance the light scattering and light trapping ability of amorphous silicon solar cells. The textured AZO film etched with HNO 3 exhibits optimized optical properties (T% ≧ 80% over entire wavelength, haze ratio > 40% at 550 nm wavelength) and excellent electrical properties (ρ = 5.86 × 10 −4 Ωcm). Scanning electron microscopy and Atomic force microscopy are used to observe surface morphology and average roughness of each textured AZO films. Finally, the textured AZO films etched by H 3 PO 4 , HCl and HNO 3 were applied to front electrode layer for p–i–n amorphous silicon solar cells. The highest conversion efficiency of amorphous silicon solar cell fabricated on HNO 3 -etched AZO film was 7.08% with open-circuit voltage, short-circuit current density and fill factor of 895 mV, 14.92 mA/cm 2 and 0.56, respectively. It shows a significantly enhancement in the short-circuit current density and conversion efficiency by 16.2% and 20.2%, respectively, compared with the solar cell fabricated on as-grown AZO film. - Highlights: • The textured surface enhances light scattering and light trapping ability. • The HNO 3 -etched AZO film exhibits excellent optical and electrical properties. • The efficiency of a-Si:H solar cell fabricated on HNO 3 -etched AZO film was 7.08%. • The short-circuit current density enhances to 16.2%. • The conversion efficiency enhances to 20.2%

  10. Antibacterial Activity Of ternary semiconductor compounds AgInSe2 Nanoparticles Synthesized by Simple Chemical Method

    Science.gov (United States)

    Shehab, A. A.; Fadaam, S. A.; Abd, A. N.; Mustafa, M. H.

    2018-05-01

    In this objective AgInSe2Nanoparticles (AgInSe2 NPs) were prepared by a simple chemical method (SCM). The optica structural l and morphological properties of the synthesized AgInSe2 NPs swere investigated by using UVVI absorption atomic force microscopy AFMmf, Fourier Transform Infrared Spectroscopy and x-ray diffraction. The resistance of bacteria represents a trouble and the outlook for the use of antibiotics in the future until now uncertain. Measures must be taken to decrease this problem. Antibacterial activity of the AgInSe2 nanoparticles were exposed against several pathogenic bacteriaa including Klebsiella pneumonia KPa, Staphylococcus aureus, Bacillus subtili, Enterobacter Cloacae and Esherichia Coliby. Using a good spread method the results showed that AgInSe2 NPs had inhibitory effect versus some pathogenic bacteria with suppression area 18, 14 and 17 mm for SAgInSe2 NPs had an inhibitory effect against S Bacillus Subtilis 11 mm K EnterobactercCloacae 12 mm.

  11. A systematic study of the controlled generation of crystalline iron oxide nanoparticles on graphene using a chemical etching process

    Directory of Open Access Journals (Sweden)

    Peter Krauß

    2017-09-01

    Full Text Available Chemical vapor deposition (CVD of carbon precursors employing a metal catalyst is a well-established method for synthesizing high-quality single-layer graphene. Yet the main challenge of the CVD process is the required transfer of a graphene layer from the substrate surface onto a chosen target substrate. This process is delicate and can severely degrade the quality of the transferred graphene. The protective polymer coatings typically used generate residues and contamination on the ultrathin graphene layer. In this work, we have developed a graphene transfer process which works without a coating and allows the transfer of graphene onto arbitrary substrates without the need for any additional post-processing. During the course of our transfer studies, we found that the etching process that is usually employed can lead to contamination of the graphene layer with the Faradaic etchant component FeCl3, resulting in the deposition of iron oxide FexOy nanoparticles on the graphene surface. We systematically analyzed the removal of the copper substrate layer and verified that crystalline iron oxide nanoparticles could be generated in controllable density on the graphene surface when this process is optimized. It was further confirmed that the FexOy particles on graphene are active in the catalytic growth of carbon nanotubes when employing a water-assisted CVD process.

  12. Synthesis, characterizations and anti-bacterial activities of pure and Ag doped CdO nanoparticles by chemical precipitation method.

    Science.gov (United States)

    Sivakumar, S; Venkatesan, A; Soundhirarajan, P; Khatiwada, Chandra Prasad

    2015-02-05

    In the present study, synthesized pure and Ag (1%, 2%, and 3%) doped Cadmium Oxide (CdO) nanoparticles by chemical precipitation method. Then, the synthesized products were characterized by thermo gravimetric-differential thermal analysis (TG-DTA), X-ray diffraction (XRD) analysis, Fourier transform infrared (FT-IR) spectroscopy, Ultra violet-Vis diffused reflectance spectroscopy (UV-Vis-DRS), Scanning electron microscopy (SEM), Energy dispersive X-rays (EDX) spectroscopy, and anti-bacterial activities, respectively. The transition temperatures and phase transitions of Cd(OH)2 to CdO at 400°C was confirmed by TG-DTA analysis. The XRD patterns show the cubic shape and average particle sizes are 21, 40, 34, and 37nm, respectively for pure and Ag doped samples. FT-IR study confirmed the presence of CdO and Ag at 677 and 459cm(-1), respectively. UV-Vis-DRS study shows the variation on direct and indirect band gaps. The surface morphologies and elemental analysis have been confirmed from SEM and with EDX. In addition, the synthesized products have been characterized by antibacterial activities against Gram-positive and negative bacteria. Further, the present investigation suggests that CdO nanoparticles have the great potential applications on various industrial and medical fields of research. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Bipyridine based metallogels: an unprecedented difference in photochemical and chemical reduction in the in situ nanoparticle formation.

    Science.gov (United States)

    Tatikonda, Rajendhraprasad; Bertula, Kia; Nonappa; Hietala, Sami; Rissanen, Kari; Haukka, Matti

    2017-02-28

    Metal co-ordination induced supramolecular gelation of low molecular weight organic ligands is a rapidly expanding area of research due to the potential in creating hierarchically self-assembled multi-stimuli responsive materials. In this context, structurally simple O-methylpyridine derivatives of 4,4'-dihydroxy-2,2'-bipyridine ligands are reported. Upon complexation with Ag(i) ions in aqueous dimethyl sulfoxide (DMSO) solutions the ligands spontaneously form metallosupramolecular gels at concentrations as low as 0.6 w/v%. The metal ions induce the self-assembly of three dimensional (3D) fibrillar networks followed by the spontaneous in situ reduction of the Ag-centers to silver nanoparticles (AgNPs) when exposed to daylight. Significant size and morphological differences of the AgNP's was observed between the standard chemical and photochemical reduction of the metallogels. The gelation ability, the nanoparticle formation and rheological properties were found to be depend on the ligand structure, while the strength of the gels is affected by the water content of the gels.

  14. “Miswak” Based Green Synthesis of Silver Nanoparticles: Evaluation and Comparison of Their Microbicidal Activities with the Chemical Synthesis

    Directory of Open Access Journals (Sweden)

    Mohammed Rafi Shaik

    2016-11-01

    Full Text Available Microbicidal potential of silver nanoparticles (Ag-NPs can be drastically improved by improving their solubility or wettability in the aqueous medium. In the present study, we report the synthesis of both green and chemical synthesis of Ag-NPs, and evaluate the effect of the dispersion qualities of as-prepared Ag-NPs from both methods on their antimicrobial activities. The green synthesis of Ag-NPs is carried out by using an aqueous solution of readily available Salvadora persica L. root extract (RE as a bioreductant. The formation of highly crystalline Ag-NPs was established by various analytical and microscopic techniques. The rich phenolic contents of S. persica L. RE (Miswak not only promoted the reduction and formation of NPs but they also facilitated the stabilization of the Ag-NPs, which was established by Fourier transform infrared spectroscopy (FT-IR analysis. Furthermore, the influence of the volume of the RE on the size and the dispersion qualities of the NPs was also evaluated. It was revealed that with increasing the volume of RE the size of the NPs was deteriorated, whereas at lower concentrations of RE smaller size and less aggregated NPs were obtained. During this study, the antimicrobial activities of both chemically and green synthesized Ag-NPs, along with the aqueous RE of S. persica L., were evaluated against various microorganisms. It was observed that the green synthesized Ag-NPs exhibit comparable or slightly higher antibacterial activities than the chemically obtained Ag-NPs.

  15. Particle-assisted wetting

    International Nuclear Information System (INIS)

    Xu Hui; Yan Feng; Tierno, Pietro; Marczewski, Dawid; Goedel, Werner A

    2005-01-01

    Wetting of a solid surface by a liquid is dramatically impeded if either the solid or the liquid is decorated by particles. Here it is shown that in the case of contact between two liquids the opposite effect may occur; mixtures of a hydrophobic liquid and suitable particles form wetting layers on a water surface though the liquid alone is non-wetting. In these wetting layers, the particles adsorb to, and partially penetrate through, the liquid/air and/or the liquid/water interface. This formation of wetting layers can be explained by the reduction in total interfacial energy due to the replacement of part of the fluid/fluid interfaces by the particles. It is most prominent if the contact angles at the fluid/fluid/particle contact lines are close to 90 0

  16. Direct large-scale synthesis of perovskite barium strontium titanate nano-particles from solutions

    International Nuclear Information System (INIS)

    Qi Jianquan; Wang Yu; Wan Pingchen; Long Tuli; Chan, Helen Lai Wah

    2005-01-01

    This paper reports a wet chemical synthesis technique for large-scale fabrication of perovskite barium strontium titanate nano-particles near room temperature and under ambient pressure. The process employs titanium alkoxide and alkali earth hydroxides as starting materials and involves very simple operation steps. Particle size and crystallinity of the particles are controllable by changing the processing parameters. Observations by X-ray diffraction, scanning electron microscopy and transmission electron microscopy TEM indicate that the particles are well-crystallized, chemically stoichiometric and ∼50nm in diameter. The nanoparticles can be sintered into ceramics at 1150 deg. C and show typical ferroelectric hysteresis loops

  17. Structural studies of mechano-chemically synthesized CuIn1-xGaxSe2 nanoparticles

    International Nuclear Information System (INIS)

    Vidhya, B.; Velumani, S.; Arenas-Alatorre, Jesus A.; Morales-Acevedo, Arturo; Asomoza, R.; Chavez-Carvayar, J.A.

    2010-01-01

    CuInGaSe 2 is a I-III-VI 2 semiconducting material of tetragonal chalcopyrite structure. It is a very prominent absorber layer for photovoltaic devices. Particle-based coating process for CIGS is considered to be promising technique with relatively simple procedures and low initial investment. In the present work CIGS nanoparticle precursors suitable for screen-printing ink has been prepared by ball milling. High purity elemental copper granules, selenium and indium powders and fine chips of gallium were used as starting materials. First the ball milling was carried out for CuIn 1-x Ga x Se 2 (x = 0.5) with (i) 10 ml of ethyl alcohol (ii) 5 ml of tetra ethylene glycol (wet) and (iii) 1 ml of ethylene diamine (semi-dry) for a milling time of 3 h and the results are not stoichiometric. In order to obtain an improved stoichiometric composition dry ball milling of elemental sources for three different compositions of CuIn 1-x Ga x Se 2 (x = 0.25, 0.5 and 0.75) has been carried out. X-ray diffraction analysis revealed the presence of (1 1 2), (2 2 0)/(2 0 4), (3 1 2)/(1 1 6), (4 0 0) and (3 3 2) reflections for all the milled powders. These reflections correspond to chalcopyrite structure of CIGS. Shift in peaks towards higher value of 2θ is observed with the increase in Ga composition. Average grain size calculated by Scherrer's formula is found to be around 13 nm for the dry samples milled for 1.5 h and 7-8 nm for the samples wet milled for 3 h. Lattice constants 'a' and 'c' are found to decrease with the increase in concentration of Gallium. FESEM analysis revealed a strong agglomeration of the particles and the particle size varied from 11 to 30 nm for the dry-milled samples. Composition of milled powders has been studied by energy dispersive X-ray analysis. TEM analysis revealed the presence of nanocrystalline particles and SAED pattern corresponds to (1 1 2), (2 2 0)/(2 0 4), (5 1 2)/(4 1 7) and (6 2 0)/(6 0 4) diffraction peaks of CIGS. From the HRTEM analysis

  18. Chemically controlled interfacial nanoparticle assembly into nanoporous gold films for electrochemical applications

    DEFF Research Database (Denmark)

    Christiansen, Mikkel U. -B.; Seselj, Nedjeljko; Engelbrekt, Christian

    2018-01-01

    at the liquid/air interface starting from gold nanoparticles (AuNPs) in an aqueous solution, providing silver-free gold films. Chloroauric acid is reduced to AuNP building blocks by 2-(N-morpholino)ethanesulfonic acid, which also acts as a protecting agent and pH buffer. By adding potassium chloride before Au......, they can be controlled by varying the temperature, chloride concentration, ionic strength, and protonation of the buffer. cNPGF formation is attributed to the destabilization of AuNPs at the air–liquid interface. The developed method generates electrochemically stable cNPGFs up to 20 cm2 in size...

  19. Using chemical wet-etching methods of textured AZO films on a-Si:H solar cells for efficient light trapping

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Guo-Sheng; Li, Chien-Yu; Huang, Kuo-Chan; Houng, Mau-Phon, E-mail: mphoung@eembox.ncku.edu.tw

    2015-06-15

    In this paper, Al-doped ZnO (AZO) films are deposited on glasses substrate by RF magnetron sputtering. The optical, electrical and morphological properties of AZO films textured by wet-etching with different etchants, H{sub 3}PO{sub 4}, HCl, and HNO{sub 3} are studied. It is found that the textured structure could enhance the light scattering and light trapping ability of amorphous silicon solar cells. The textured AZO film etched with HNO{sub 3} exhibits optimized optical properties (T% ≧ 80% over entire wavelength, haze ratio > 40% at 550 nm wavelength) and excellent electrical properties (ρ = 5.86 × 10{sup −4} Ωcm). Scanning electron microscopy and Atomic force microscopy are used to observe surface morphology and average roughness of each textured AZO films. Finally, the textured AZO films etched by H{sub 3}PO{sub 4}, HCl and HNO{sub 3} were applied to front electrode layer for p–i–n amorphous silicon solar cells. The highest conversion efficiency of amorphous silicon solar cell fabricated on HNO{sub 3}-etched AZO film was 7.08% with open-circuit voltage, short-circuit current density and fill factor of 895 mV, 14.92 mA/cm{sup 2} and 0.56, respectively. It shows a significantly enhancement in the short-circuit current density and conversion efficiency by 16.2% and 20.2%, respectively, compared with the solar cell fabricated on as-grown AZO film. - Highlights: • The textured surface enhances light scattering and light trapping ability. • The HNO{sub 3}-etched AZO film exhibits excellent optical and electrical properties. • The efficiency of a-Si:H solar cell fabricated on HNO{sub 3}-etched AZO film was 7.08%. • The short-circuit current density enhances to 16.2%. • The conversion efficiency enhances to 20.2%.

  20. Repairing Nanoparticle Surface Defects.

    Science.gov (United States)

    Marino, Emanuele; Kodger, Thomas E; Crisp, Ryan W; Timmerman, Dolf; MacArthur, Katherine E; Heggen, Marc; Schall, Peter

    2017-10-23

    Solar devices based on semiconductor nanoparticles require the use of conductive ligands; however, replacing the native, insulating ligands with conductive metal chalcogenide complexes introduces structural defects within the crystalline nanostructure that act as traps for charge carriers. We utilized atomically thin semiconductor nanoplatelets as a convenient platform for studying, both microscopically and spectroscopically, the development of defects during ligand exchange with the conductive ligands Na 4 SnS 4 and (NH 4 ) 4 Sn 2 S 6 . These defects can be repaired via mild chemical or thermal routes, through the addition of L-type ligands or wet annealing, respectively. This results in a higher-quality, conductive, colloidally stable nanomaterial that may be used as the active film in optoelectronic devices. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  1. Thermal, optical and vibrational studies of tyrosine doped LaF3:Ce nanoparticles for bioimaging and biotagging

    Science.gov (United States)

    Singh, Amit T.

    2018-05-01

    Upconversion quantum dots of tyrosine doped LaF3:Ce nanoparticles have been synthesized by wet chemical route. The thermal studies (TGA/DTA) confirm the crystallinity and stability of different phases of synthesized nanoparticles. The UV-Visible spectra show multiple absorption edges at 215.60 nm and 243.10 nm indicating quantum dot nature of the synthesized nanoparticles. The PL spectra showed upconversion with sharp emission peak at 615 nm (red colour). The FT-RAMAN spectra of the synthesized nanoparticles show the modification of the surface of the nanoparticles in the form of functional groups and skeletal groups. Upconversion nature of the synthesized nanoparticles indicates their potential application in bioimaging and biotagging.

  2. Carboxymethyl chitosan based nanocomposites containing chemically bonded quantum dots and magnetic nanoparticles

    Science.gov (United States)

    Ding, Yongling; Yin, Hong; Chen, Rui; Bai, Ru; Chen, Chunying; Hao, Xiaojuan; Shen, Shirley; Sun, Kangning; Liu, Futian

    2018-03-01

    A biocompatible nanocomposite consisting of fluorescent quantum dots (QDs) and magnetic nanoparticles (MNPs) has been constructed via carboxymethyl chitosan (CMCS), resulting in magnetic-fluorescent nanoparticles (MFNPs). In these MFNPs, QDs and MNPs are successfully conjugated via covalent bonds onto the surface of CMCS. The composite retains favorable magnetic and fluorescent properties and shows a good colloidal stability in physiological environments. Folate (FA) as a specific targeting ligand was further incorporated into the nanocomposites to form a delivery vehicle with a targeting function. The therapeutic activity was achieved by loading chemotherapeutic drug doxorubicin (DOX) through electrostatic and hydrophobic interactions. The cumulative DOX release profile shows pH-sensitive. Both flow cytometry analysis and confocal laser scanning microscopic observation suggested that these nanocomposites were uptaken by cancer cells via FA receptor-mediated endocytosis pathway. In summary, the CMCS based nanocomposites developed in this work have a great potential for effective cancer-targeting and drug delivery, as well as in situ cellular imaging.

  3. Obtaining Highly Crystalline Barium Sulphate Nanoparticles via Chemical Precipitation and Quenching in Absence of Polymer Stabilizers

    Directory of Open Access Journals (Sweden)

    Ángela B. Sifontes

    2015-01-01

    Full Text Available Here we report the synthesis of barium sulphate (BaSO4 nanoparticles from Ba(OH2/BaCl2 solutions by a combined method of precipitation and quenching in absence of polymer stabilizers. Transmission electron microscopy (HRTEM, Fourier transforms infrared spectroscopy (FTIR, and X-ray diffraction (XRD were employed to characterize the particles. The Scherrer formula was applied to estimate the particle size using the width of the diffraction peaks. The obtained results indicate that the synthesized material is mainly composed of nanocrystalline barite, with nearly spherical morphology, and diameters ranging from 4 to 92 nm. The lattice images of nanoparticles were clearly observed by HRTEM, indicating a high degree of crystallinity and phase purity. In addition, agglomerates with diameters between 20 and 300 nm were observed in both lattice images and dynamic light scattering measurements. The latter allowed obtaining the particle size distribution, the evolution of the aggregate size in time of BaSO4 in aqueous solutions, and the sedimentation rate of these solutions from turbidimetry measurements. A short discussion on the possible medical applications is presented.

  4. Physico-chemical changes of ZnO nanoparticles with different size and surface chemistry under physiological pH conditions.

    Science.gov (United States)

    Gwak, Gyeong-Hyeon; Lee, Won-Jae; Paek, Seung-Min; Oh, Jae-Min

    2015-03-01

    We studied the physico-chemical properties of ZnO nanoparticles under physiological pH conditions (gastric, intestinal and plasma) as functions of their size (20 and 70 nm) and surface chemistry (pristine, L-serine, or citrate coating). ZnO nanoparticles were dispersed in phosphate buffered saline under physiological pH conditions and aliquots were collected at specific time points (0.5, 1, 4, 10 and 24 h) for further characterization. The pH values of the aqueous ZnO colloids at each condition were in the neutral to slightly basic range and showed different patterns depending on the original size and surface chemistry of the ZnO nanoparticles. The gastric pH condition was found to significantly dissolve ZnO nanoparticles up to 18-30 wt%, while the intestinal or plasma pH conditions resulted in much lower dissolution amounts than expected. Based on the X-ray diffraction patterns and X-ray absorption spectra, we identified partial phase transition of the ZnO nanoparticles from wurtzite to Zn(OH)2 under the intestinal and plasma pH conditions. Using scanning electron microscopy, we verified that the overall particle size and morphology of all ZnO nanoparticles were maintained regardless of the pH. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. The influence of reaction times on structural, optical and luminescence properties of cadmium telluride nanoparticles prepared by wet-chemical process

    Energy Technology Data Exchange (ETDEWEB)

    Kiprotich, Sharon, E-mail: KiprotichS@qwa.ufs.ac.za [Department of Physics, University of the Free State (QwaQwa campus), Private Bag X-13, Phuthaditjhaba 9866 (South Africa); Dejene, Francis B.; Ungula, Jatani [Department of Physics, University of the Free State (QwaQwa campus), Private Bag X-13, Phuthaditjhaba 9866 (South Africa); Onani, Martin O. [Departments of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

    2016-01-01

    This paper explains one pot synthesis of type II water soluble L-cysteine capped cadmium telluride (CdTe) core shell quantum dots using cadmium acetate, potassium tellurite and L-cysteine as the starting materials. The reaction was carried out in a single three necked flask without nitrogen under reflux at 100 °C. Results from PL show a sharp absorption excitonic band edge of the CdTe core with respect to the core shell which loses its shoulder during the growth of the shell on the core. The PL spectra indicate a drastic shift in emission window of the core which is simultaneously accompanied by an increase in emission intensity. X-ray diffraction pattern confirms the formation of hexagonal phase for all samples. Some difference in absorption edges were observed due to varying synthesis time of CdTe NPs. The position of the absorption band is observed to shift towards the lower wavelength side for shorter durations of synthesis.

  6. A Wet Chemistry Laboratory Cell

    Science.gov (United States)

    2008-01-01

    This picture of NASA's Phoenix Mars Lander's Wet Chemistry Laboratory (WCL) cell is labeled with components responsible for mixing Martian soil with water from Earth, adding chemicals and measuring the solution chemistry. WCL is part of the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument suite on board the Phoenix lander. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  7. Erosion corrosion in wet steam

    International Nuclear Information System (INIS)

    Tavast, J.

    1988-03-01

    The effect of different remedies against erosion corrosion in wet steam has been studied in Barsebaeck 1. Accessible steam systems were inspected in 1984, 1985 and 1986. The effect of hydrogen peroxide injection of the transport of corrosion products in the condensate and feed water systems has also been followed through chemical analyses. The most important results of the project are: - Low alloy chromium steels with a chromium content of 1-2% have shown excellent resistance to erosion corrosion in wet steam. - A thermally sprayed coating has shown good resistance to erosion corrosion in wet steam. In a few areas with restricted accessibility minor attacks have been found. A thermally sprayed aluminium oxide coating has given poor results. - Large areas in the moisture separator/reheater and in steam extraction no. 3 have been passivated by injection of 20 ppb hydrogen peroxide to the high pressure steam. In other inspected systems no significant effect was found. Measurements of the wall thickness in steam extraction no. 3 showed a reduced rate of attack. - The injection of 20 ppb hydrogen peroxide has not resulted in any significant reduction of the iron level result is contrary to that of earlier tests. An increase to 40 ppb resulted in a slight decrease of the iron level. - None of the feared disadvantages with hydrogen peroxide injection has been observed. The chromium and cobalt levels did not increase during the injection. Neither did the lifetime of the precoat condensate filters decrease. (author)

  8. Quantitative and simultaneous analysis of the polarity of polycrystalline ZnO seed layers and related nanowires grown by wet chemical deposition

    Science.gov (United States)

    Guillemin, Sophie; Parize, Romain; Carabetta, Joseph; Cantelli, Valentina; Albertini, David; Gautier, Brice; Brémond, Georges; Fong, Dillon D.; Renevier, Hubert; Consonni, Vincent

    2017-03-01

    The polarity in ZnO nanowires is an important issue since it strongly affects surface configuration and reactivity, nucleation and growth, electro-optical properties, and nanoscale-engineering device performances. However, measuring statistically the polarity of ZnO nanowire arrays grown by chemical bath deposition and elucidating its correlation with the polarity of the underneath polycrystalline ZnO seed layer grown by the sol-gel process represents a major difficulty. To address that issue, we combine resonant x-ray diffraction (XRD) at Zn K-edge using synchrotron radiation with piezoelectric force microscopy and polarity-sensitive chemical etching to statistically investigate the polarity of more than 107 nano-objects both on the macroscopic and local microscopic scales, respectively. By using high temperature annealing under an argon atmosphere, it is shown that the compact, highly c-axis oriented ZnO seed layer is more than 92% Zn-polar and that only a few small O-polar ZnO grains with an amount less than 8% are formed. Correlatively, the resulting ZnO nanowires are also found to be Zn-polar, indicating that their polarity is transferred from the c-axis oriented ZnO grains acting as nucleation sites in the seed layer. These findings pave the way for the development of new strategies to form unipolar ZnO nanowire arrays as a requirement for a number of nanoscale-engineering devices like piezoelectric nanogenerators. They also highlight the great advantage of resonant XRD as a macroscopic, non-destructive method to simultaneously and statistically measure the polarity of ZnO nanowire arrays and of the underneath ZnO seed layer.

  9. Polycrystalline and Mesoporous 3-D Bi2O3 Nanostructured Negatrodes for High-Energy and Power-Asymmetric Supercapacitors: Superfast Room-Temperature Direct Wet Chemical Growth.

    Science.gov (United States)

    Shinde, Nanasaheb M; Xia, Qi Xun; Yun, Je Moon; Mane, Rajaram S; Kim, Kwang Ho

    2018-04-04

    Superfast (≤10 min) room-temperature (300 K) chemical synthesis of three-dimensional (3-D) polycrystalline and mesoporous bismuth(III) oxide (Bi 2 O 3 ) nanostructured negatrode (as an abbreviation of negative electrode) materials, viz., coconut shell, marigold, honey nest cross section and rose with different surface areas, charge transfer resistances, and electrochemical performances essential for energy storage, harvesting, and even catalysis devices, are directly grown onto Ni foam without and with poly(ethylene glycol), ethylene glycol, and ammonium fluoride surfactants, respectively. Smaller diffusion lengths, caused by the involvement of irregular crevices, allow electrolyte ions to infiltrate deeply, increasing the utility of inner active sites for the following electrochemical performance. A marigold 3-D Bi 2 O 3 electrode of 58 m 2 ·g -1 surface area has demonstrated a specific capacitance of 447 F·g -1 at 2 A·g -1 and chemical stability of 85% even after 5000 redox cycles at 10 A·g -1 in a 6 M KOH electrolyte solution, which were higher than those of other morphology negatrode materials. An asymmetric supercapacitor (AS) device assembled with marigold Bi 2 O 3 negatrode and manganese(II) carbonate quantum dots/nickel hydrogen-manganese(II)-carbonate (MnCO 3 QDs/NiH-Mn-CO 3 ) positrode corroborates as high as 51 Wh·kg -1 energy at 1500 W·kg -1 power and nearly 81% cycling stability even after 5000 cycles. The obtained results were comparable or superior to the values reported previously for other Bi 2 O 3 morphologies. This AS assembly glowed a red-light-emitting diode for 20 min, demonstrating the scientific and industrial credentials of the developed superfast Bi 2 O 3 nanostructured negatrodes in assembling various energy storage devices.

  10. Lithium-ions diffusion kinetic in LiFePO4/carbon nanoparticles synthesized by microwave plasma chemical vapor deposition for lithium-ion batteries

    Science.gov (United States)

    Gao, Chao; Zhou, Jian; Liu, Guizhen; Wang, Lin

    2018-03-01

    Olivine structure LiFePO4/carbon nanoparticles are synthesized successfully using a microwave plasma chemical vapor deposition (MPCVD) method. Microwave is an effective method to synthesize nanomaterials, the LiFePO4/carbon nanoparticles with high crystallinity can shorten diffusion routes for ionic transfer and electron tunneling. Meanwhile, a high quality, complete and homogenous carbon layer with appropriate thickness coating on the surface of LiFePO4 particles during in situ chemical vapor deposition process, which can ensure that electrons are able to transfer fast enough from all sides. Electrochemical impedance spectroscopy (EIS) is carried out to collect information about the kinetic behavior of lithium diffusion in LiFePO4/carbon nanoparticles during the charging and discharging processes. The chemical diffusion coefficients of lithium ions, DLi, are calculated in the range of 10-15-10-9 cm2s-1. Nanoscale LiFePO4/carbon particles show the longer regions of the faster solid-solution diffusion, and corresponding to the narrower region of the slower two-phase diffusion during the insertion/exaction of lithium ions. The CV and galvanostatic charge-discharge measurements show that the LiFePO4/carbon nanoparticles perform an excellent electrochemical performance, especially the high rate capacity and cycle life.

  11. A wet-tolerant adhesive patch inspired by protuberances in suction cups of octopi

    Science.gov (United States)

    Baik, Sangyul; Kim, Da Wan; Park, Youngjin; Lee, Tae-Jin; Ho Bhang, Suk; Pang, Changhyun

    2017-06-01

    Adhesion strategies that rely on mechanical interlocking or molecular attractions between surfaces can suffer when coming into contact with liquids. Thus far, artificial wet and dry adhesives have included hierarchical mushroom-shaped or porous structures that allow suction or capillarity, supramolecular structures comprising nanoparticles, and chemistry-based attractants that use various protein polyelectrolytes. However, it is challenging to develop adhesives that are simple to make and also perform well—and repeatedly—under both wet and dry conditions, while avoiding non-chemical contamination on the adhered surfaces. Here we present an artificial, biologically inspired, reversible wet/dry adhesion system that is based on the dome-like protuberances found in the suction cups of octopi. To mimic the architecture of these protuberances, we use a simple, solution-based, air-trap technique that involves fabricating a patterned structure as a polymeric master, and using it to produce a reversed architecture, without any sophisticated chemical syntheses or surface modifications. The micrometre-scale domes in our artificial adhesive enhance the suction stress. This octopus-inspired system exhibits strong, reversible, highly repeatable adhesion to silicon wafers, glass, and rough skin surfaces under various conditions (dry, moist, under water and under oil). To demonstrate a potential application, we also used our adhesive to transport a large silicon wafer in air and under water without any resulting surface contamination.

  12. Nanoparticle-triggered in situ catalytic chemical reactions for tumour-specific therapy.

    Science.gov (United States)

    Lin, Han; Chen, Yu; Shi, Jianlin

    2018-03-21

    Tumour chemotherapy employs highly cytotoxic chemodrugs, which kill both cancer and normal cells by cellular apoptosis or necrosis non-selectively. Catalysing/triggering the specific chemical reactions only inside tumour tissues can generate abundant and special chemicals and products locally to initiate a series of unique biological and pathologic effects, which may enable tumour-specific theranostic effects to combat cancer without bringing about significant side effects on normal tissues. Nevertheless, chemical reaction-initiated selective tumour therapy strongly depends on the advances in chemistry, materials science, nanotechnology and biomedicine. This emerging cross-disciplinary research area is substantially different from conventional cancer-theranostic modalities in clinics. In response to the fast developments in cancer theranostics based on intratumoural catalytic chemical reactions, this tutorial review summarizes the very-recent research progress in the design and synthesis of representative nanoplatforms with intriguing nanostructures, compositions, physiochemical properties and biological behaviours for versatile catalytic chemical reaction-enabled cancer treatments, mainly by either endogenous tumour microenvironment (TME) triggering or exogenous physical irradiation. These unique intratumoural chemical reactions can be used in tumour-starving therapy, chemodynamic therapy, gas therapy, alleviation of tumour hypoxia, TME-responsive diagnostic imaging and stimuli-responsive drug release, and even externally triggered versatile therapeutics. In particular, the challenges and future developments of such a novel type of cancer-theranostic modality are discussed in detail to understand the future developments and prospects in this research area as far as possible. It is highly expected that this kind of unique tumour-specific therapeutics by triggering specific in situ catalytic chemical reactions inside tumours would provide a novel but efficient

  13. Ultra-high sensitive hydrazine chemical sensor based on low-temperature grown ZnO nanoparticles

    International Nuclear Information System (INIS)

    Mehta, S.K.; Singh, Kulvinder; Umar, Ahmad; Chaudhary, G.R.; Singh, Sukhjinder

    2012-01-01

    Graphical abstract: Systematic representation of the fabricated amperometric hydrazine chemical sensor based on ZnO NPs/Au modified electrode. Highlights: ► Synthesis of well-crystalline ZnO NPs has been achieved in aqueous solution. ► ZnO NPs act as efficient electron mediators for hydrazine sensor. ► Extremely high sensitivity and low-detection limit have been obtained. - Abstract: Using well-crystalline ZnO nanoparticles (NPs), an ultra high sensitive hydrazine amperometric sensor has been fabricated and reported in this paper. The ZnO NPs have been synthesized by very simple aqueous solution process at 90 °C and characterized in detail in terms of their morphological, compositional, structural and optical properties. The detailed investigations reveal that the synthesized products are well-crystalline NPs, possessing wurtzite hexagonal phase and exhibit good optical properties. The fabricated amperometric hydrazine sensor exhibits ultra-high sensitivity of ∼97.133 μA cm −2 μM −1 and very low-detection limit of 147.54 nM. To the best of our knowledge, this is the first report in which an ultra-high sensitivity and low-detection limit have been obtained for the hydrazine chemical sensor based on ZnO nanostructures.

  14. Effects of Particle Size on Chemical Speciation and Bioavailability of Copper to Earthworms ( Eisenia fetida ) Exposed to Copper Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    J Unrine; O Tsyusko; S Hunyadi; J Judy; P Bertsch

    2011-12-31

    To investigate the role of particle size on the oxidation, bioavailability, and adverse effects of manufactured Cu nanoparticles (NPs) in soils, we exposed the earthworm Eisenia fetida to a series of concentrations of commercially produced NPs labeled as 20- to 40-nm or <100-nm Cu in artificial soil media. Effects on growth, mortality, reproduction, and expression of a variety of genes associated with metal homeostasis, general stress, and oxidative stress were measured. We also used X-ray absorption spectroscopy and scanning X-ray fluorescence microscopy to characterize changes in chemical speciation and spatial distribution of the NPs in soil media and earthworm tissues. Exposure concentrations of Cu NPs up to 65 mg kg{sup -1} caused no adverse effects on ecologically relevant endpoints. Increases in metallothionein expression occurred at concentrations exceeding 20 mg kg-1 of Cu NPs and concentrations exceeding 10 mg kg{sup -1} of CuSO{sub 4} Based on the relationship of Cu tissue concentration to metallothionein expression level and the spatial distribution and chemical speciation of Cu in the tissues, we conclude that Cu ions and oxidized Cu NPs were taken up by the earthworms. This study suggests that oxidized Cu NPs may enter food chains from soil but that adverse effects in earthworms are likely to occur only at relatively high concentrations (>65 mg Cu kg{sup -1} soil).

  15. Decontamination of chemical warfare sulfur mustard agent simulant by ZnO nanoparticles

    Science.gov (United States)

    Sadeghi, Meysam; Yekta, Sina; Ghaedi, Hamed

    2016-07-01

    In this study, zinc oxide nanoparticles (ZnO NPs) have been surveyed to decontaminate the chloroethyl phenyl sulfide as a sulfur mustard agent simulant. Prior to the reaction, ZnO NPs were successfully prepared through sol-gel method in the absence and presence of polyvinyl alcohol (PVA). PVA was utilized as a capping agent to control the agglomeration of the nanoparticles. The formation, morphology, elemental component, and crystalline size of nanoscale ZnO were certified and characterized by SEM/EDX, XRD, and FT-IR techniques. The decontamination (adsorption and destruction) was tracked by the GC-FID analysis, in which the effects of polarity of the media, such as isopropanol, acetone and n-hexane, reaction time intervals from 1 up to 18 h, and different temperatures, including 25, 35, 45, and 55 °C, on the catalytic/decontaminative capability of the surface of ZnO NPs/PVA were investigated and discussed, respectively. Results demonstrated that maximum decontamination (100 %) occurred in n-hexane solvent at 55 °C after 1 h. On the other hand, the obtained results for the acetone and isopropanol solvents were lower than expected. GC-MS chromatograms confirmed the formation of hydroxyl ethyl phenyl sulfide and phenyl vinyl sulfide as the destruction reaction products. Furthermore, these chromatograms proved the role of hydrolysis and elimination mechanisms on the catalyst considering its surface Bronsted and Lewis acid sites. A non-polar solvent aids material transfer to the reactive surface acid sites without blocking these sites.

  16. Reversible switching of wetting properties and erasable patterning of polymer surfaces using plasma oxidation and thermal treatment

    Science.gov (United States)

    Rashid, Zeeshan; Atay, Ipek; Soydan, Seren; Yagci, M. Baris; Jonáš, Alexandr; Yilgor, Emel; Kiraz, Alper; Yilgor, Iskender

    2018-05-01

    Polymer surfaces reversibly switchable from superhydrophobic to superhydrophilic by exposure to oxygen plasma and subsequent thermal treatment are demonstrated. Two inherently different polymers, hydrophobic segmented polydimethylsiloxane-urea copolymer (TPSC) and hydrophilic poly(methyl methacrylate) (PMMA) are modified with fumed silica nanoparticles to prepare superhydrophobic surfaces with roughness on nanometer to micrometer scale. Smooth TPSC and PMMA surfaces are also used as control samples. Regardless of their chemical structure and surface topography, all surfaces display completely reversible wetting behavior changing from hydrophobic to hydrophilic and back for many cycles upon plasma oxidation followed by thermal annealing. Influence of plasma power, plasma exposure time, annealing temperature and annealing time on the wetting behavior of polymeric surfaces are investigated. Surface compositions, textures and topographies are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and white light interferometry (WLI), before and after oxidation and thermal annealing. Wetting properties of the surfaces are determined by measuring their static, advancing and receding water contact angle. We conclude that the chemical structure and surface topography of the polymers play a relatively minor role in reversible wetting behavior, where the essential factors are surface oxidation and migration of polymer molecules to the surface upon thermal annealing. Reconfigurable water channels on polymer surfaces are produced by plasma treatment using a mask and thermal annealing cycles. Such patterned reconfigurable hydrophilic regions can find use in surface microfluidics and optofluidics applications.

  17. Application of nanoparticle of rock phosphate and biofertilizer in increasing some soil chemical characteristics of variable charge soil

    Science.gov (United States)

    Devnita, Rina; Joy, Benny; Arifin, Mahfud; Hudaya, Ridha; Oktaviani, Nurul

    2018-02-01

    Soils in Indonesia are dominated by variable charge soils where the technology like fertilization did not give the same result as the soils with permanent charge. The objectives of this research is to increase some chemical characteristic of variable charge soils by using the high negative charge ameliorations like rock phosphate in nanoparticle combined with biofertilizer. The research used a complete randomized experimental design in factorial with two factors. The first factor was nanoparticle of rock phosphate consists of four doses on soil weight percentage (0%, 2.5%, 5.0% and 7.5%). The second factor was biofertilizer consisted of two doses (without biofertilizer and 1 g.kg-1 soil biofertilizer). The combination treatments replicated three times. Variable charge soil used was Andisol. Andisol and the treatments were incubated for 4 months. Soil samples were taken after one and four months during incubation period to be analyzed for P-retention, available P and potential P. The result showed that all combinations of rock phosphate and biofertilizer decreased the P-retention to 75-77% after one month. Independently, application of 7.5% of rock phosphate decreased P-retention to 87.22% after four months, increased available P (245.37 and 19.12 mg.kg-1) and potential P (1354.78 and 3000.99 mg/100) after one and four months. Independently, biofertilizer increased the P-retention to 91.66% after four months, decreased available P to 121.55 mg.kg-1 after one month but increased to 12.55 mg.kg-1 after four months, decreased potential P to 635.30 after one month but increased to 1810.40 mg.100 g-1 after four months.

  18. ABB wet flue gas desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Niijhawan, P.

    1994-12-31

    The wet limestone process for flue gas desulfurization (FGD) is outlined. The following topics are discussed: wet flue gas desulfurization, wet FGD characteristics, wet scrubbers, ABB wet FGD experience, wet FGD forced oxidation, advanced limestone FGD systems, key design elements, open spray tower design, spray tower vs. packed tower, important performance parameters, SO{sub 2} removal efficiency, influence by L/G, limestone utilization, wet FGD commercial database, particulate removal efficiencies, materials of construction, nozzle layout, spray nozzles, recycle pumps, mist elimination, horizontal flow demister, mist eliminator washing, reagent preparation system, spray tower FGDS power consumption, flue gas reheat options, byproduct conditioning system, and wet limestone system.

  19. Room-Temperature Wet Chemical Synthesis of Au NPs/TiH2/Nanocarved Ti Self-Supported Electrocatalysts for Highly Efficient H2 Generation.

    Science.gov (United States)

    Amin, Mohammed A; Fadlallah, Sahar A; Alosaimi, Ghaida S; Ahmed, Emad M; Mostafa, Nasser Y; Roussel, Pascal; Szunerits, Sabine; Boukherroub, Rabah

    2017-09-06

    Self-supported electrocatalysts are a new class of materials exhibiting high catalytic performance for various electrochemical processes and can be directly equipped in energy conversion devices. We present here, for the first time, sparse Au NPs self-supported on etched Ti (nanocarved Ti substrate self-supported with TiH 2 ) as promising catalysts for the electrochemical generation of hydrogen (H 2 ) in KOH solutions. Cleaned, as-polished Ti substrates were etched in highly concentrated sulfuric acid solutions without and with 0.1 M NH 4 F at room temperature for 15 min. These two etching processes yielded a thin layer of TiH 2 (the corrosion product of the etching process) self-supported on nanocarved Ti substrates with different morphologies. While F - -free etching process led to formation of parallel channels (average width: 200 nm), where each channel consists of an array of rounded cavities (average width: 150 nm), etching in the presence of F - yielded Ti surface carved with nanogrooves (average width: 100 nm) in parallel orientation. Au NPs were then grown in situ (self-supported) on such etched surfaces via immersion in a standard gold solution at room temperature without using stabilizers or reducing agents, producing Au NPs/TiH 2 /nanostructured Ti catalysts. These materials were characterized by scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS), grazing incidence X-ray diffraction (GIXRD), and X-ray photoelectron spectroscopy (XPS). GIXRD confirmed the formation of Au 2 Ti phase, thus referring to strong chemical interaction between the supported Au NPs and the substrate surface (also evidenced from XPS) as well as a titanium hydride phase of chemical composition TiH 2 . Electrochemical measurements in 0.1 M KOH solution revealed outstanding hydrogen evolution reaction (HER) electrocatalytic activity for our synthesized catalysts, with Au NPs/TiH 2 /nanogrooved Ti catalyst being the best one among them. It exhibited fast kinetics

  20. Chemical modification of polysulfone: composite anionic exchange membrane with TiO2 nano-particles

    CSIR Research Space (South Africa)

    Nonjola, PT

    2013-04-01

    Full Text Available -chemical properties studied by means of SEM and XRD techniques suggested the uniform and homogeneous distribution of TiO2 at 2.5wt. % loading, and negligible agglomeration at 10wt % loading, also indicated enhancement of crystalline character of these membranes...

  1. Thermal dewetting with a chemically heterogeneous nano-template for self-assembled L1(0) FePt nanoparticle arrays.

    Science.gov (United States)

    Wang, Liang-Wei; Cheng, Chung-Fu; Liao, Jung-Wei; Wang, Chiu-Yen; Wang, Ding-Shuo; Huang, Kuo-Feng; Lin, Tzu-Ying; Ho, Rong-Ming; Chen, Lih-Juann; Lai, Chih-Huang

    2016-02-21

    A design for the fabrication of metallic nanoparticles is presented by thermal dewetting with a chemically heterogeneous nano-template. For the template, we fabricate a nanostructured polystyrene-b-polydimethylsiloxane (PS-b-PDMS) film on a Si|SiO2 substrate, followed by a thermal annealing and reactive ion etching (RIE) process. This gives a template composed of an ordered hexagonal array of SiOC hemispheres emerging in the polystyrene matrix. After the deposition of a FePt film on this template, we utilize the rapid thermal annealing (RTA) process, which provides in-plane stress, to achieve thermal dewetting and structural ordering of FePt simultaneously. Since the template is composed of different composition surfaces with periodically varied morphologies, it offers more tuning knobs to manipulate the nanostructures. We show that both the decrease in the area of the PS matrix and the increase in the strain energy relaxation transfer the dewetted pattern from the randomly distributed nanoparticles into a hexagonal periodic array of L10 FePt nanoparticles. Transmission electron microscopy with the in situ heating stage reveals the evolution of the dewetting process, and confirms that the positions of nanoparticles are aligned with those of the SiOC hemispheres. The nanoparticles formed by this template-dewetting show an average diameter and center-to-center distance of 19.30 ± 2.09 nm and 39.85 ± 4.80 nm, respectively. The hexagonal array of FePt nanoparticles reveals a large coercivity of 1.5 T, much larger than the nanoparticles fabricated by top-down approaches. This approach offers an efficient pathway toward self-assembled nanostructures in a wide range of material systems.

  2. Size effects on electrical properties of chemically grown zinc oxide nanoparticles

    Science.gov (United States)

    Rathod, K. N.; Joshi, Zalak; Dhruv, Davit; Gadani, Keval; Boricha, Hetal; Joshi, A. D.; Solanki, P. S.; Shah, N. A.

    2018-03-01

    In the present article, we study ZnO nanoparticles grown by cost effective sol–gel technique for various electrical properties. Structural studies performed by x-ray diffraction (XRD) revealed hexagonal unit cell phase with no observed impurities. Transmission electron microscopy (TEM) and particle size analyzer showed increased average particle size due to agglomeration effect with higher sintering. Dielectric constant (ε‧) decreases with increase in frequency because of the disability of dipoles to follow higher electric field. With higher sintering, dielectric constant reduced owing to the important role of increased formation of oxygen vacancy defects. Universal dielectric response (UDR) was verified by straight line fitting of log (fε‧) versus log (f) plots. All samples exhibit UDR behavior and with higher sintering more contribution from crystal cores. Impedance studies suggest an important role of boundary density while Cole–Cole (Z″ versus Z‧) plots have been studied for the relaxation behavior of the samples. Average normalized change (ANC) in impedance has been studied for all the samples wherein boundaries play an important role. Frequency dependent electrical conductivity has been understood on the basis of Jonscher’s universal power law. Jonscher’s law fits suggest that conduction of charge carrier is possible in the context of correlated barrier hopping (CBH) mechanism for lower temperature sintered sample while for higher temperature sintered ZnO samples, Maxwell–Wagner (M–W) relaxation process has been determined.

  3. Ultrafast chemical interface scattering as an additional decay channel for nascent nonthermal electrons in small metal nanoparticles.

    Science.gov (United States)

    Bauer, Christophe; Abid, Jean-Pierre; Fermin, David; Girault, Hubert H

    2004-05-15

    The use of 4.2 nm gold nanoparticles wrapped in an adsorbates shell and embedded in a TiO2 metal oxide matrix gives the opportunity to investigate ultrafast electron-electron scattering dynamics in combination with electronic surface phenomena via the surface plasmon lifetimes. These gold nanoparticles (NPs) exhibit a large nonclassical broadening of the surface plasmon band, which is attributed to a chemical interface damping. The acceleration of the loss of surface plasmon phase coherence indicates that the energy and the momentum of the collective electrons can be dissipated into electronic affinity levels of adsorbates. As a result of the preparation process, gold NPs are wrapped in a shell of sulfate compounds that gives rise to a large density of interfacial molecules confined between Au and TiO2, as revealed by Fourier-transform-infrared spectroscopy. A detailed analysis of the transient absorption spectra obtained by broadband femtosecond transient absorption spectroscopy allows separating electron-electron and electron-phonon interaction. Internal thermalization times (electron-electron scattering) are determined by probing the decay of nascent nonthermal electrons (NNEs) and the build-up of the Fermi-Dirac electron distribution, giving time constants of 540 to 760 fs at 0.42 and 0.34 eV from the Fermi level, respectively. Comparison with literature data reveals that lifetimes of NNEs measured for these small gold NPs are more than four times longer than for silver NPs with similar sizes. The surprisingly long internal thermalization time is attributed to an additional decay mechanism (besides the classical e-e scattering) for the energy loss of NNEs, identified as the ultrafast chemical interface scattering process. NNEs experience an inelastic resonant scattering process into unoccupied electronic states of adsorbates, that directly act as an efficient heat bath, via the excitation of molecular vibrational modes. The two-temperature model is no longer

  4. Effects of major parameters of nanoparticles on their physical and chemical properties and recent application of nanodrug delivery system in targeted chemotherapy.

    Science.gov (United States)

    Zhang, Jing; Tang, Hua; Liu, Zefa; Chen, Baoan

    2017-01-01

    Chemotherapy is still one of the main cancer therapy treatments, but the curative effect of chemotherapy is relatively low, as such the development of a new cancer treatment is highly desirable. The gradual maturation of nanotechnology provides an innovative perspective not only for cancer therapy but also for many other applications. There are a diverse variety of nanoparticles available, and choosing the appropriate carriers according to the demand is the key issue. The performance of nanoparticles is affected by many parameters, mainly size, shape, surface charge, and toxicity. Using nanoparticles as the carriers to realize passive targeting and active targeting can improve the efficacy of chemotherapy drugs significantly, reduce the mortality rate of cancer patients, and improve the quality of life of patients. In recent years, there has been extensive research on nanocarriers. In this review, the effects of several major parameters of nanoparticles on their physical and chemical properties are reviewed, and then the recent progress in the application of several commonly used nanoparticles is presented.

  5. The Effect of Alumina and Magnesia Supported Germanium Nanoparticles on the Growth of Carbon Nanotubes in the Chemical Vapor Deposition Method

    Directory of Open Access Journals (Sweden)

    Ghazaleh Allaedini

    2015-01-01

    Full Text Available The effect of alumina and magnesia supported germanium (Ge nanoparticles on the synthesis of carbon nanotubes (CNTs using the chemical vapor deposition (CVD method in atmospheric pressure was investigated. The TEM micrographs confirmed the formation of carbon nanotubes, and the field emission scanning electron microscopy (FESEM analysis suggested a tip-growth mechanism for the grown carbon nanotubes. The X-ray diffraction (XRD pattern indicated a graphitic nature of the carbon nanotubes. The obtained CNTs using Ge nanoparticles supported by MgO resulted in a higher degree of graphitization than the CNTs obtained using Ge nanoparticles supported by Al2O3. Raman spectroscopy analysis of the CNTs confirmed the presence of radial breathing modes (RBM, which verified the formation of CNTs. High frequency Raman analysis demonstrated that the degree of graphitization of the synthesized CNTs using magnesia supported Ge nanoparticles is higher than that of the alumina supported Ge nanoparticles with the values of (ID/IG ratios equal to 0.45 and 0.73, respectively.

  6. Eco-friendly and green synthesis of silver nanoparticles using leaf extract of Strychnos potatorum Linn.F. and their bactericidal activities.

    Science.gov (United States)

    Kagithoju, Srikanth; Godishala, Vikram; Nanna, Rama Swamy

    2015-10-01

    Inspired green synthesis of metallic nanoparticles is evolving as an important branch of nanotechnology. Traditionally these are manufactured by wet chemical methods which require toxic and flammable chemicals. We report for the first time an economic and eco-friendly green synthesis of silver nanoparticles using Strychnos potatorum aqueous leaf extract from 3 mM silver nitrate solution. Nanoparticles thus formed are confirmed and characterized by using UV-Vis absorption spectroscopy, SEM and XRD measurements. The XRD and SEM analysis showed the average particle size of nanoparticles as 28 nm as well as revealed their (mixed, i.e., cubic and hexagonal) structure. Further, these green synthesized nanoparticles showed bactericidal activity against multidrug-resistant human pathogenic bacteria.

  7. Wet gas sampling

    Energy Technology Data Exchange (ETDEWEB)

    Welker, T.F.

    1997-07-01

    The quality of gas has changed drastically in the past few years. Most gas is wet with hydrocarbons, water, and heavier contaminants that tend to condense if not handled properly. If a gas stream is contaminated with condensables, the sampling of that stream must be done in a manner that will ensure all of the components in the stream are introduced into the sample container as the composite. The sampling and handling of wet gas is extremely difficult under ideal conditions. There are no ideal conditions in the real world. The problems related to offshore operations and other wet gas systems, as well as the transportation of the sample, are additional problems that must be overcome if the analysis is to mean anything to the producer and gatherer. The sampling of wet gas systems is decidedly more difficult than sampling conventional dry gas systems. Wet gas systems were generally going to result in the measurement of one heating value at the inlet of the pipe and a drastic reduction in the heating value of the gas at the outlet end of the system. This is caused by the fallout or accumulation of the heavier products that, at the inlet, may be in the vapor state in the pipeline; hence, the high gravity and high BTU. But, in fact, because of pressure and temperature variances, these liquids condense and form a liquid that is actually running down the pipe as a stream or is accumulated in drips to be blown from the system. (author)

  8. Rapid and ultrasensitive colorimetric detection of mercury(II) by chemically initiated aggregation of gold nanoparticles

    International Nuclear Information System (INIS)

    Chen, Yinji; Chen, Wei; Yao, Li; Deng, Yi; Pan, Daodong; Cao, Jinxuan; Ogabiela, Edward; Adeloju, Samuel B.

    2015-01-01

    The article describes a method for rapid and visual determination of Hg(II) ion using unmodified gold nanoparticles (Au-NPs). It involves the addition of Au-NPs to a solution containing Hg(II) ions which, however, does not induce a color change. Next, a solution of lysine is added which induces the aggregation of the Au-NPs and causes the color of the solution to change from wine-red to purple. The whole on-site detection process can be executed in less than 15 min. Other amines (ethylenediamine, arginine, and melamine) were also investigated with respect to their capability to induce aggregation. Notably, only amines containing more than one amino group were found to be effective, but a 0.4 μM and pH 8 solution of lysine was found to give the best results. The detection limits for Hg (II) are 8.4 pM (for instrumental read-out) and 10 pM (for visual read-out). To the best of our knowledge, this LOD is better than those reported for any other existing rapid screening methods. The assay is not interfered by the presence of other common metal ions even if present in 1000-fold excess over Hg(II) concentration. It was successfully applied to the determination of Hg(II) in spiked tap water samples. We perceive that this method provides an excellent tool for rapid and ultrasensitive on-site determination of Hg(II) ions at low cost, with relative ease and minimal operation. (author)

  9. Degradability of superparamagnetic nanoparticles in a model of intracellular environment: follow-up of magnetic, structural and chemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Michael; Wilhelm, Claire; Gazeau, Florence [Laboratoire Matiere et Systemes Complexes, UMR 7057, CNRS and Universite Paris Diderot, 10 rue Alice Domon et Leonie Duquet, 75205 Paris cedex 13 (France); Lagarde, Florence [Universite de Lyon 1, Laboratoire des Sciences Analytiques, UMR 5180 CNRS-UCBL, bat CPE, 43, boulevard du 11 novembre 1918, 69622 Villeurbanne cedex (France); Maraloiu, Valentin-Adrian; Blanchin, Marie-Genevieve [Universite de Lyon 1, Laboratoire PMCN UMR 5586 CNRS-UCBL, 69622 Villeurbanne cedex (France); Gendron, Francois, E-mail: florence.gazeau@univ-paris-diderot.fr [Institut des Nanosciences de Paris (INSP) UMR 7588, CNRS and Universite Pierre et Marie Curie 110 rue de Lourmel, 75015 Paris (France)

    2010-10-01

    The unique magnetic properties of iron oxide nanoparticles have paved the way for various biomedical applications, such as magnetic resonance cellular imaging or magnetically induced therapeutic hyperthermia. Living cells interact with nanoparticles by internalizing them within intracellular acidic compartments. Although no acute toxicity of iron oxide nanoparticles has been reported up to now, the mechanisms of nanoparticle degradation by the cellular environment are still unknown. In the organism, the long term integrity and physical state of iron-based nanoparticles are challenged by iron homeostasis. In this study, we monitored the degradation of 7 nm sized maghemite nanoparticles in a medium mimicking the intracellular environment. Magnetic nanoparticles with three distinct surface coatings, currently evaluated as MRI contrast agents, were shown to exhibit different kinetics of dissolution at an acidic pH in the presence of a citrate chelating agent. Our assessment of the physical state of the nanoparticles during degradation revealed that the magnetic properties, size distribution and structure of the remaining nanocrystals were identical to those of the initial suspension. This result suggests a model for nanoparticle degradation with rapidly dissolved nanocrystals and a reservoir of intact nanoparticles.

  10. Chemical-wet Synthesis and Electrochemistry of LiNi1/3Co1/3Mn1/3O2 Cathode Materials for Li-ion Batteries

    International Nuclear Information System (INIS)

    Hsieh, Chien-Te; Mo, Chung-Yu; Chen, Yu-Fu; Chung, Yi-Jou

    2013-01-01

    LiNi 1/3 Co 1/3 Mn 1/3 O 2 (LNCM) with a well-ordered layered structure, confirmed by X-ray diffraction, was synthesized by the chemical-wet synthesis incorporated with (i) a pulse microwave-assisted heating of LNCM precursors and (ii) a carbon coating technique. The microwave irradiation periods (i.e., 5–20 min) and amount of carbon additive (i.e., glucose content: 0.1–0.75%) served as key factors in modifying as-prepared LNCM powders. The electrochemical performance of as-prepared LNCM cathodes was well characterized by cyclic voltammetry and charge–discharge cycling at 0.1–5C. Both appropriate microwave heating and carbon coating significantly improve discharge capacity, rate capability, and cycling stability of LNCM cathodes. This improved performance can be attributed to the facts that an appropriate microwave heating of LNCM precursors induces low cation mixing of the layered lattices and the carbon coating enables the creation of outer circuit of charge-transfer pathway, preventing cathode corrosion from direct contact to the electrolyte. The C-coated LNCM cathode shows the increased capacity retention from 70.2 to 93.3% after 50 cycles at 1C. On the basis of the experimental results, both the microwave heating and the carbon coating provide a feasible potential way to improve the electrochemical performance of LNCM cathode, benefiting the development of Li-ion batteries

  11. Multiwalled Carbon Nanotube Forest Grown via Chemical Vapor Deposition from Iron Catalyst Nanoparticles, by XPS

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, David S.; Kanyal, Supriya S.; Madaan, Nitesh; Vail, Michael A.; Dadson, Andrew; Engelhard, Mark H.; Linford, Matthew R.

    2013-09-25

    Carbon nanotubes (CNTs) have unique chemical and physical properties. Herein, we report an XPS analysis of a forest of multiwalled CNTs using monochromatic Al Kα radiation. Survey scans show only one element: carbon. The carbon 1s peak is centered 284.5 eV. The C 1s envelope also shows the expected π → π* shake-up peak at ca. 291 eV. The valence band and carbon KVV Auger signals are presented. When patterned, the CNT forests can be used as a template for subsequent deposition of metal oxides to make thin layer chromatography plates.1-3

  12. Wet storage integrity update

    International Nuclear Information System (INIS)

    Bailey, W.J.; Johnson, A.B. Jr.

    1983-09-01

    This report includes information from various studies performed under the Wet Storage Task of the Spent Fuel Integrity Project of the Commercial Spent Fuel Management (CSFM) Program at Pacific Northwest Laboratory. An overview of recent developments in the technology of wet storage of spent water reactor fuel is presented. Licensee Event Reports pertaining to spent fuel pools and the associated performance of spent fuel and storage components during wet storage are discussed. The current status of fuel that was examined under the CSFM Program is described. Assessments of the effect of boric acid in spent fuel pool water on the corrosion and stress corrosion cracking of stainless steel and the stress corrosion cracking of stainless steel piping containing stagnant water at spent fuel pools are discussed. A list of pertinent publications is included. 84 references, 21 figures, 11 tables

  13. Do Nanoparticle Physico-Chemical Properties and Developmental Exposure Window Influence Nano ZnO Embryotoxicity in Xenopus laevis?

    Directory of Open Access Journals (Sweden)

    Patrizia Bonfanti

    2015-07-01

    Full Text Available The growing global production of zinc oxide nanoparticles (ZnONPs suggests a realistic increase in the environmental exposure to such a nanomaterial, making the knowledge of its biological reactivity and its safe-by-design synthesis mandatory. In this study, the embryotoxicity of ZnONPs (1–100 mg/L specifically synthesized for industrial purposes with different sizes, shapes (round, rod and surface coatings (PEG, PVP was tested using the frog embryo teratogenesis assay-Xenopus (FETAX to identify potential target tissues and the most sensitive developmental stages. The ZnONPs did not cause embryolethality, but induced a high incidence of malformations, in particular misfolded gut and abdominal edema. Smaller, round NPs were more effective than the bigger, rod ones, and PEGylation determined a reduction in embryotoxicity. Ingestion appeared to be the most relevant exposure route. Only the embryos exposed from the stomodeum opening showed anatomical and histological lesions to the intestine, mainly referable to a swelling of paracellular spaces among enterocytes. In conclusion, ZnONPs differing in shape and surface coating displayed similar toxicity in X. laevis embryos and shared the same target organ. Nevertheless, we cannot exclude that the physico-chemical characteristics may influence the severity of such effects. Further research efforts are mandatory to ensure the synthesis of safer nano-ZnO-containing products.

  14. Plasma Synthesis of Nanoparticles for Nanocomposite Energy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Peter C. Kong; Alex W. Kawczak

    2008-09-01

    The nanocomposite energy applications for plasma reactor produced nanoparticles are reviewed. Nanoparticles are commonly defined as particles less than 100 nm in diameter. Due to this small size, nanoparticles have a high surface-to-volume ratio. This increases the surface energy compared to the bulk material. The high surface-to-volume ratio and size effects (quantum effects) give nanoparticles distinctive chemical, electronic, optical, magnetic and mechanical properties from those of the bulk material. Nanoparticles synthesis can be grouped into 3 broad approaches. The first one is wet phase synthesis (sol-gel processing), the second is mechanical attrition, and the third is gas-phase synthesis (aerosol). The properties of the final product may differ significantly depending on the fabrication route. Currently, there are no economical large-scale production processes for nanoparticles. This hinders the widespread applications of nanomaterials in products. The Idaho National Laboratory (INL) is engaging in research and development of advanced modular hybrid plasma reactors for low cost production of nanoparticles that is predicted to accelerate application research and enable the formation of technology innovation alliances that will result in the commercial production of nanocomposites for alternative energy production devices such as fuel cells, photovoltaics and electrochemical double layer capacitors.

  15. Wetting of real surfaces

    CERN Document Server

    Bormashenko, Edward Yu

    2013-01-01

    The problem of wetting and drop dynamics on various surfaces is very interesting from both the scientificas well as thepractical viewpoint, and subject of intense research.The results are scattered across papers in journals, sothis workwill meet the need for a unifying, comprehensive work.

  16. Wet oxidation of quinoline

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Kilen, H.H.

    1998-01-01

    The influence of oxygen pressure (0.4 and 2 MPa). reaction time (30 and 60 min) and temperature (260 and 280 degrees C) on the wet oxidation of quinoline has been studied. The dominant parameters for the decomposition of quinoline were oxygen pressure and reaction temperature. whereas the reactio...

  17. Synthesis and characterization of hydroxyapatite nanoparticles by chemical precipitation method for potential application in water treatment

    Science.gov (United States)

    Joshi, Parth; Patel, Chirag; Vyas, Meet

    2018-05-01

    Hydroxyapatite (HA) is a unique material having high adsorption capacity of heavy metals, high ion exchange capacity, high biological compatibility, low water solubility, high stability under reducing and oxidizing conditions, availability and low cost. As the starting reagents, analytical grade Ca(NO3)2.4H2O, (NH4)2HPO4 and NaOH were used. In order to study the factors that have an important influence on the chemical precipitation process a experimental platform has been designed for hydroxyapatite synthesis. The addition of Phosphorus pentaoxide to Calcium hydroxide was carried out slowly with simultaneous stirring. After addition, solution was aged for maturation. The precipitate was dried at 80°C overnight and further heat treated at 600°C for 2 hours. The dried and calcined particles were characterized by Fourier transform infra-red spectroscopy and Thermo gravimetric analysis. The particle size and morphology were studied using transmission electron microscopy. TEM examination of the treated powders displayed particles of polygon morphology with dimensions 30-70 nm in length. The FT-IR spectra for sample confirmed the formation of hydroxyapatite. Purity of the prepared Hydroxyapatite has been confirmed by XRD analysis.

  18. Aqueous chemical route synthesis and the effect of calcination temperature on the structural and optical properties of ZnO nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohammad Ramzan Parra

    2014-10-01

    Full Text Available This article reports the controlled size of ZnO nanoparticles synthesized via simple aqueous chemical route without the involvement of any capping agent. The effect of different calcination temperatures on the size of the ZnO nanoparticles was investigated. X-ray diffraction (XRD results indicated that all the samples have crystalline wurtzite phase, and peak broadening analysis was used to evaluate the average crystallite size and lattice strain using Scherrer's equation and Williamson–Hall (W–H method. Morphology and elemental compositions were investigated using atomic force microscopy (AFM and scanning electron microscopy (SEM with energy-dispersive X-ray (EDX spectroscopy. The average crystallite size of ZnO nanoparticles estimated from Scherrer's formula and W–H analysis was found to increase with the increase in calcination temperature. These results were in good agreement with AFM results. Optical properties were investigated using UV–vis spectroscopy in diffused reflectance (DR mode, with a sharp increase in reflectivity at 375 nm and the material has a strong reflective characteristic after 420 nm at 500 °C calcination temperature. Furthermore, photoluminescence spectroscopic results revealed intensive ultraviolet (UV emission with reduced defect concentrations and a slight shifting in band gap energies with increased calcination temperature from 200 °C to 500 °C. This study suggests that the as-prepared ZnO nanoparticles with bandgap tunability might be utilized as window layer in optoelectronic devices.

  19. Wetting of flat gradient surfaces.

    Science.gov (United States)

    Bormashenko, Edward

    2018-04-01

    Gradient, chemically modified, flat surfaces enable directed transport of droplets. Calculation of apparent contact angles inherent for gradient surfaces is challenging even for atomically flat ones. Wetting of gradient, flat solid surfaces is treated within the variational approach, under which the contact line is free to move along the substrate. Transversality conditions of the variational problem give rise to the generalized Young equation valid for gradient solid surfaces. The apparent (equilibrium) contact angle of a droplet, placed on a gradient surface depends on the radius of the contact line and the values of derivatives of interfacial tensions. The linear approximation of the problem is considered. It is demonstrated that the contact angle hysteresis is inevitable on gradient surfaces. Electrowetting of gradient surfaces is discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

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

    OpenAIRE

    Yang Yongkun; Burkhard Peter

    2012-01-01

    Abstract Background Gold nanoparticles are useful tools for biological applications due to their attractive physical and chemical properties. Their applications can be further expanded when they are functionalized with biological molecules. The biological molecules not only provide the interfaces for interactions between nanoparticles and biological environment, but also contribute their biological functions to the nanoparticles. Therefore, we used self-assembling protein nanoparticles (SAPNs...

  1. Study of Coating Geometries and Photoluminescence Properties of Metal Nanoparticles/Graphite Composites

    Directory of Open Access Journals (Sweden)

    Pasquale Barone

    2014-01-01

    Full Text Available In this work we present the results of a study of growth and characterization of metal nanoparticles (Ag, Au, and Co/carbon surfaces. The nanoparticles grew by laser ablation technique and their dimensions were controlled by light scattering study and AFM microscopy before their insertion on graphite surface. Nanoparticles appear randomly disposed on carbon surfaces aggregating to form big particles only in the case of silver. The different behavior of metal nanoparticles on carbon surface was explained in terms of different metal wetting of surface, in agreement with previous theoretical results of He et al. Chemical information, obtained by X-ray photoelectron spectroscopy, indicated that the doping process is a simple physisorption while the interfacial interaction between particles and carbon layers causes local defects in graphite structure and the appearance of a strong photoluminescence signal for all composites. Moreover, the visible optical absorption decreases about 10% indicating the progressive metallization of carbon surface.

  2. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  3. Combined silver nanoparticles and temperature effects in the Cape River crab Potamanautes perlatus - Interactions between chemical and climatic stressors

    CSIR Research Space (South Africa)

    Walters, Chavon R

    2017-03-01

    Full Text Available The influence of silver nanoparticles (AgNPs) and temperature variation on toxicity and oxidative stress responses were investigated in the tissues of the Cape River crab Potamanautes perlatus following a seven-day exposure period. Toxicity...

  4. Multi-functionality Redefined with Colloidal Carotene Carbon Nanoparticles for Synchronized Chemical Imaging, Enriched Cellular Uptake and Therapy

    OpenAIRE

    Misra, Santosh K.; Mukherjee, Prabuddha; Chang, Huei-Huei; Tiwari, Saumya; Gryka, Mark; Bhargava, Rohit; Pan, Dipanjan

    2016-01-01

    Typically, multiplexing high nanoparticle uptake, imaging, and therapy requires careful integration of three different functions of a multiscale molecular-particle assembly. Here, we present a simpler approach to multiplexing by utilizing one component of the system for multiple functions. Specifically, we successfully synthesized and characterized colloidal carotene carbon nanoparticle (C3-NP), in which a single functional molecule served a threefold purpose. First, the presence of carotene ...

  5. Foam-film-stabilized liquid bridge networks in evaporative lithography and wet granular matter

    KAUST Repository

    Vakarelski, Ivan Uriev

    2013-04-23

    Evaporative lithography using latex particle templates is a novel approach for the self-assembly of suspension-dispersed nanoparticles into ordered microwire networks. The phenomenon that drives the self-assembly process is the propagation of a network of interconnected liquid bridges between the template particles and the underlying substrate. With the aid of video microscopy, we demonstrate that these liquid bridges are in fact the border zone between the underlying substrate and foam films vertical to the substrate, which are formed during the evaporation of the liquid from the suspension. The stability of the foam films and thus the liquid bridge network stability are due to the presence of a small amount of surfactant in the evaporating solution. We show that the same type of foam-film-stabilized liquid bridge network can also propagate in 3D clusters of spherical particles, which has important implications for the understanding of wet granular matter. © 2013 American Chemical Society.

  6. Performance improvement of ionic surfactant flooding in carbonate rock samples by use of nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Ahmadi

    2016-07-01

    Full Text Available Abstract Various surfactants have been used in upstream petroleum processes like chemical flooding. Ultimately, the performance of these surfactants depends on their ability to reduce the interfacial tension between oil and water. The surfactant concentration in the aqueous solution decreases owing to the loss of the surfactant on the rock surface in the injection process. The main objective of this paper is to inhibit the surfactant loss by means of adding nanoparticles. Sodium dodecyl sulfate and silica nanoparticles were used as ionic surfactant and nanoparticles in our experiments, respectively. AEROSIL® 816 and AEROSIL® 200 are hydrophobic and hydrophilic nanoparticles. To determine the adsorption loss of the surfactant onto rock samples, a conductivity approach was used. Real carbonate rock samples were used as the solid phase in adsorption experiments. It should be noted that the rock samples were water wet. This paper describes how equilibrium adsorption was investigated by examining adsorption behavior in a system of carbonate sample (solid phase and surfactant solution (aqueous phase. The initial surfactant and nanoparticle concentrations were 500–5000 and 500–2000 ppm, respectively. The rate of surfactant losses was extremely dependent on the concentration of the surfactant in the system, and the adsorption of the surfactant decreased with an increase in the nanoparticle concentration. Also, the hydrophilic nanoparticles are more effective than the hydrophobic nanoparticles.

  7. Controlled fabrication of the strong emission YVO{sub 4}:Eu{sup 3+} nanoparticles and nanowires by microwave assisted chemical synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Huong, Tran Thu, E-mail: tthuongims@gmail.com [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Vinh, Le Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Department of Chemistry, Hanoi University of Mining and Geology (Viet Nam); Phuong, Ha Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Department of Chemistry, Hanoi University of Medicine (Viet Nam); Khuyen, Hoang Thi [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Anh, Tran Kim [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Duy Tan University, 14/25 Quang Trung, Da Nang (Viet Nam); Tu, Vu Duc [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Physics, National Chung Cheng University, 168 University Road, Min-Hsiung, Chia-Yi 62102, Taiwan (China); Minh, Le Quoc [Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam); Duy Tan University, 14/25 Quang Trung, Da Nang (Viet Nam)

    2016-05-15

    In this report, we are presenting the controlled fabrication results of the strong emission YVO{sub 4}: Eu{sup 3+} nanoparticles and nanowires by microwave which is assisted chemical synthesis. The effects of incorporated synthesis conditions such as microwave irradiated powers, pH values and concentration of chemical composition on properties of nanomaterials are also investigated to obtain the controllable size and homogenous morphology. Morphological and optical properties of YVO{sub 4}: Eu{sup 3+} prepared products which have been characterized by X-ray diffraction (XRD), field emission micrcroscopy (FESEM) and photoluminescence spectroscopy. As based from result of synthesized samples, we found that the changing of pH values, microwave irradiated powers and chemical composition rise to change reform the size and shape of materials from nanoparticles (diameter about 20 nm) to wires shape (with about 500÷800 nm length and 10÷20 nm width). The photoluminescence (PL) spectroscopy measurements of YVO{sub 4}: Eu{sup 3+} nanostructure materials under UV excitation showed that: the strong luminescence in red region with narrow lines corresponding to the intra-4f transitions of {sup 5}D{sub 0}–{sup 7}F{sub j} (j=1, 2, 3, and 4) of Eu{sup 3+} ions with the highest luminescence intensity of {sup 5}D{sub 0}→{sup 7}F{sub 2} transition. - Highlights: • The strong emission YVO{sub 4}:Eu{sup 3+} nanostructure materials were successfully synthesized by microwave assisted chemical synthesis. • The size, morphology and luminescence of the YVO{sub 4}:Eu{sup 3+} nanostructure materials can be controlled by the solution pH, microwave irradiated powers and chemical composition. • These YVO{sub 4}:Eu{sup 3+} nanostructure materials above can potentially applied in various fields of application, especially in luminescent labeling and visualization in biomedical application.

  8. Metal/Carbon Hybrid Nanostructures Produced from Plasma-Enhanced Chemical Vapor Deposition over Nafion-Supported Electrochemically Deposited Cobalt Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohammad Islam

    2018-04-01

    Full Text Available In this work, we report development of hybrid nanostructures of metal nanoparticles (NP and carbon nanostructures with strong potential for catalysis, sensing, and energy applications. First, the etched silicon wafer substrates were passivated for subsequent electrochemical (EC processing through grafting of nitro phenyl groups using para-nitrobenzene diazonium (PNBT. The X-ray photoelectron spectroscope (XPS and atomic force microscope (AFM studies confirmed presence of few layers. Cobalt-based nanoparticles were produced over dip or spin coated Nafion films under different EC reduction conditions, namely CoSO4 salt concentration (0.1 M, 1 mM, reduction time (5, 20 s, and indirect or direct EC reduction route. Extensive AFM examination revealed NP formation with different attributes (size, distribution depending on electrochemistry conditions. While relatively large NP with >100 nm size and bimodal distribution were obtained after 20 s EC reduction in H3BO3 following Co2+ ion uptake, ultrafine NP (<10 nm could be produced from EC reduction in CoSO4 and H3BO3 mixed solution with some tendency to form oxides. Different carbon nanostructures including few-walled or multiwalled carbon nanotubes (CNT and carbon nanosheets were grown in a C2H2/NH3 plasma using the plasma-enhanced chemical vapor deposition technique. The devised processing routes enable size controlled synthesis of cobalt nanoparticles and metal/carbon hybrid nanostructures with unique microstructural features.

  9. The role of catalytic nanoparticle pretreatment on the growth of vertically aligned carbon nanotubes by hot-filament chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki-Hwan; Gohier, Aurélien; Bourée, Jean Eric; Châtelet, Marc; Cojocaru, Costel-Sorin, E-mail: costel-sorin.cojocaru@polytechnique.edu

    2015-01-30

    The effect of atomic hydrogen assisted pre-treatment on the growth of vertically aligned carbon nanotubes using hot-filament chemical vapor deposition was investigated. Iron nanoparticle catalysts were formed on an aluminum oxide support layer by spraying of iron chloride salt solutions as catalyst precursor. It is found that pre-treatment time and process temperature tune the density as well as the shape and the structure of the grown carbon nanotubes. An optimum pre-treatment time can be found for the growth of long and well aligned carbon nanotubes, densely packed to each other. To provide insight on this behavior, the iron catalytic nanoparticles formed after the atomic hydrogen assisted pre-treatment were analyzed by atomic force microscopy. The relations between the size and the density of the as-formed catalyst and the as-grown carbon nanotube's structure and density are discussed. - Highlights: • Effect of the atomic hydrogen assisted pre-treatment on the growth of VACNT using hot-filament CVD. • Pre-treatment time and process temperature tune the density, the shape and the structure of the CNTs. • Correlations between size and density of the as-formed catalyst and the CNT’s structure and density. • Carbon nanotubes synthesized at low temperature down to 500 °C using spayed iron chloride salts. • Density of the CNT carpet adjusted by catalytic nanoparticle engineering.

  10. Assessment of the physico-chemical behavior of titanium dioxide nanoparticles in aquatic environments using multi-dimensional parameter testing

    International Nuclear Information System (INIS)

    Kammer, Frank von der; Ottofuelling, Stephanie; Hofmann, Thilo

    2010-01-01

    Assessment of the behavior and fate of engineered nanoparticles (ENPs) in natural aquatic media is crucial for the identification of environmentally critical properties of the ENPs. Here we present a methodology for testing the dispersion stability, ζ-potential and particle size of engineered nanoparticles as a function of pH and water composition. The results obtained from already widely used titanium dioxide nanoparticles (Evonik P25 and Hombikat UV-100) serve as a proof-of-concept for the proposed testing scheme. In most cases the behavior of the particles in the tested settings follows the expectations derived from classical DLVO theory for metal oxide particles with variable charge and an isoelectric point at around pH 5, but deviations also occur. Regardless of a 5-fold difference in BET specific surface area particles composed of the same core material behave in an overall comparable manner. The presented methodology can act as a basis for the development of standardised methods for comparing the behavior of different nanoparticles within aquatic systems. - The behavior of engineered nanoparticles in the aquatic environment can be elucidated using a multi-dimensional parameter set acquired by a semi automated experimental set-up.

  11. Composition tunable cobalt–nickel and cobalt–iron alloy nanoparticles below 10 nm synthesized using acetonated cobalt carbonyl

    International Nuclear Information System (INIS)

    Schooneveld, Matti M. van; Campos-Cuerva, Carlos; Pet, Jeroen; Meeldijk, Johannes D.; Rijssel, Jos van; Meijerink, Andries; Erné, Ben H.; Groot, Frank M. F. de

    2012-01-01

    A general organometallic route has been developed to synthesize Co x Ni 1−x and Co x Fe 1−x alloy nanoparticles with a fully tunable composition and a size of 4–10 nm with high yield. In contrast to previously reported synthesis methods using dicobalt octacarbonyl (Co 2 (CO) 8 ), here the cobalt–cobalt bond in the carbonyl complex is first broken with anhydrous acetone. The acetonated compound, in the presence of iron carbonyl or nickel acetylacetonate, is necessary to obtain small composition tunable alloys. This new route and insights will provide guidelines for the wet-chemical synthesis of yet unmade bimetallic alloy nanoparticles.

  12. Study the effect of calcination temperature on physical and magnetic properties of bare Cobalt nanoparticles and that coated with silica shell

    International Nuclear Information System (INIS)

    Arabi, H.; Pourarian, F.; Chahkandinejad, R.

    2012-01-01

    In this paper, in order to investigate the effect of calcination temperature on the structural and magnetic properties of cobalt nanoparticles, samples have been prepared by Co-precipitation method at different calcination temperature. Cobalt nanoparticles have been prepared by Co-precipitation method at room temperature using hydrazine as reducing in ethanol hydrazine alkaline environment. This agent reduces cobalt salts to Cobalt nanoparticles in FCC and HCP phases. Phase analysis and investigation of Structural properties of the samples using X-ray diffraction patterns (XRD) confirm the formation of hexagonal phases of Co nanoparticles. Transmission electron microscopy was used for determining the size and shape morphology of nanoparticles. Magnetic properties of these nanoparticles have been investigated using a Vibrating sample magnetometer. The results indicate that these nanoparticles are ferromagnetic at room temperature. In addition, in this paper Co nanoparticles coated with silica shell have been prepared by the wet chemical method. Transmission electron microscopy images showed the cobalt core with average diameter of 17-20 nm coated by a silica shell with thickness of 5-7 nm. Hysteresis Loop of these Co nanoparticles coated by silica shell illustrates 16.9 emu/gr for saturation magnetization at 10000 (Oe), which is much less than that of Cobalt nanoparticles

  13. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal

    2014-03-01

    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  14. Control of the shape and size of iron oxide (α-Fe2O3 nanoparticles synthesized through the chemical precipitation method

    Directory of Open Access Journals (Sweden)

    Abdelmajid Lassoued

    Full Text Available Hematite (α-Fe2O3 nanoparticles were synthesized via a simple chemical precipitation method. The impact of varying the concentration of precursor on the crystalline phase, size and morphology of α-Fe2O3 products was explored. The characteristic of the synthesized hematite nanoparticles were evaluated by X-ray diffraction (XRD, Transmission Electron Microscopy (TEM, Scanning Electron Microscopy (SEM, Fourier Transform Infra-Red (FT-IR spectroscopy, Raman spectroscopy, Differential Thermal Analysis (DTA, Thermo Gravimetric Analysis (TGA, Ultraviolet–Visible (UV–Vis analysis and Photoluminescence (PL. XRD data revealed a rhombohedral (hexagonal structure with the space group R-3c in all samples. Uniform spherical like morphology was confirmed by TEM and SEM. The result revealed that the particle sizes were varied between 21 and 82 nm and that the increase in precursor concentration (FeCl3, 6H2O is accompanied by an increase in the particle size of 21 nm for pure α-Fe2O3 synthesized with [Fe3+] = 0.05 M at 82 nm for pure α-Fe2O3 synthesized with [Fe3+] = 0.4 M. FT-IR confirms the phase purity of the nanoparticles synthesized. The Raman spectroscopy was used not only to prove that we have synthesized pure hematite but also to identify their phonon modes. The thermal behavior of compound was studied by using TGA/DTA results: The TGA showed three mass losses, whereas DTA resulted in three endothermic peaks. Besides, the optical investigation revealed that samples have an optical gap of about 2.1 eV and that this value varies as a function of the precursor concentration. Keywords: Nanoparticles, Hematite (α-Fe2O3, Precipitation, Precursor, Size, Band gap

  15. Characterizations of diverse mole of pure and Ni-doped α-Fe2O3 synthesized nanoparticles through chemical precipitation route.

    Science.gov (United States)

    Sivakumar, S; Anusuya, D; Khatiwada, Chandra Prasad; Sivasubramanian, J; Venkatesan, A; Soundhirarajan, P

    2014-07-15

    In the present study, an attempt has been made for characterization and synthesis of pure and Ni-doped α-Fe2O3 (hematite) nanoparticles by chemical precipitation method. The synthesized products have been studied by X-ray diffraction (X-RD), Fourier transform infrared (FTIR) spectroscopy, UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), vibrating sample magnetometer (VSM) and scanning electron microscopy (SEM) techniques. The estimated average diameter of α-Fe2O3 nanoparticles were calculated by using the Debye-Scherrer equation and established as 31 nm. SEM micrographs showed the surface morphology as well as structures and particles distributions of synthesized samples. The UV-Vis DRS showed the indirect and direct band gap energies of pure and Ni-doped α-Fe2O3, these were reduced from 1.9847 to 1.52 eV and 2.0503 to 1.76 eV respectively. This result suggested the dopant enhanced the semiconducting behavior of iron oxide nanoparticles to an extent proportional to its nickel doped in the α-Fe2O3. Further, the magnetic properties of the pure and doped samples were investigated by vibrating sample magnetometer (VSM) and evaluated the information of pure and doped samples exhibited saturated hysteresis loop at room temperature, which is indicating that the weak ferromagnetism in nature of our synthesized samples. In addition, it has been found from the magnetization hysteresis curves of Ni-doping, resulting from increased the saturation of magnetization and reduced the coercivity of used samples. Therefore, the present study showed the reduction in band gap energies and coercive field for α-Fe2O3 nanoparticles due to nickel doped. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Mechanism governing nanoparticle flow behaviour in porous media: insight for enhanced oil recovery applications

    Science.gov (United States)

    Agi, Augustine; Junin, Radzuan; Gbadamosi, Afeez

    2018-06-01

    Nanotechnology has found its way to petroleum engineering, it is well-accepted path in the oil and gas industry to recover more oil trapped in the reservoir. But the addition of nanoparticles to a liquid can result in the simplest flow becoming complex. To understand the working mechanism, there is a need to study the flow behaviour of these particles. This review highlights the mechanism affecting the flow of nanoparticles in porous media as it relates to enhanced oil recovery. The discussion focuses on chemical-enhanced oil recovery, a review on laboratory experiment on wettability alteration, effect of interfacial tension and the stability of emulsion and foam is discussed. The flow behaviour of nanoparticles in porous media was discussed laying emphasis on the physical aspect of the flow, the microscopic rheological behaviour and the adsorption of the nanoparticles. It was observed that nanofluids exhibit Newtonian behaviour at low shear rate and non-Newtonian behaviour at high shear rate. Gravitational and capillary forces are responsible for the shift in wettability from oil-wet to water-wet. The dominant mechanisms of foam flow process were lamellae division and bubble to multiple bubble lamellae division. In a water-wet system, the dominant mechanism of flow process and residual oil mobilization are lamellae division and emulsification, respectively. Whereas in an oil-wet system, the generation of pre-spinning continuous gas foam was the dominant mechanism. The literature review on oil displacement test and field trials indicates that nanoparticles can recover additional oil. The challenges encountered have opened new frontier for research and are highlighted herein.

  17. Biotin/Folate-decorated Human Serum Albumin Nanoparticles of Docetaxel: Comparison of Chemically Conjugated Nanostructures and Physically Loaded Nanoparticles for Targeting of Breast Cancer.

    Science.gov (United States)

    Nateghian, Navid; Goodarzi, Navid; Amini, Mohsen; Atyabi, Fatemeh; Khorramizadeh, Mohammad Reza; Dinarvand, Rassoul

    2016-01-01

    Docetaxel (DTX) is a widely used chemotherapeutic agent with very low water solubility. Conjugation of DTX to human serum albumin (HSA) is an effective way to increase its water solubility. Attachment of folic acid (FA) or biotin as targeting moieties to DTX-HSA conjugates may lead to active targeting and specific uptake by cancer cells with overexpressed FA or biotin receptors. In this study, FA or biotin molecules were attached to DTX-HSA conjugates by two different methods. In one method, FA or biotin molecules were attached to remaining NH2 residues of HSA in DTX-HSA conjugate by covalent bonds. In the second method, HSA-FA or HSA-biotin conjugates were synthesized separately and then combined by DTX-HSA conjugate in proper ratio to prepare nanoparticles containing DTX-HSA plus HSA-FA or HSA-biotin. Cell viability of different nanoparticle was evaluated on MDA-MB-231 (folate receptor positive), A549 (folate receptor negative), and 4T1 (biotin receptor positive) and showed superior cytotoxicity compared with free docetaxel (Taxotere). In vivo studies of DTX-HSA-FA and DTX-HSA-biotin conjugates in BULB/c mice, tumorized by 4T1 cell line, showed the conjugates prepared in this study were more powerful in the reduction in tumor size and increasing the survival rate when compared to free docetaxel. © 2015 John Wiley & Sons A/S.

  18. Influence of encapsulated functional lipids on crystal structure and chemical stability in solid lipid nanoparticles: Towards bioactive-based design of delivery systems.

    Science.gov (United States)

    Salminen, Hanna; Gömmel, Christina; Leuenberger, Bruno H; Weiss, Jochen

    2016-01-01

    We investigated the influence of physicochemical properties of encapsulated functional lipids--vitamin A, β-carotene and ω-3 fish oil--on the structural arrangement of solid lipid nanoparticles (SLN). The relationship between the crystal structure and chemical stability of the incorporated bioactive lipids was evaluated with different emulsifier compositions of a saponin-rich, food-grade Quillaja extract alone or combined with high-melting or low-melting lecithins. The major factors influencing the structural arrangement and chemical stability of functional lipids in solid lipid dispersions were their solubility in the aqueous phase and their crystallization temperature in relation to that of the carrier lipid. The results showed that the stabilization of the α-subcell crystals in the lattice of the carrier lipid is a key parameter for forming stable solid lipid dispersions. This study contributes to a better understanding of SLN as a function of the bioactive lipid. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Single gold nanoparticle plasmonic spectroscopy for study of chemical-dependent efflux function of single ABC transporters of single live Bacillus subtilis cells.

    Science.gov (United States)

    Browning, Lauren M; Lee, Kerry J; Cherukuri, Pavan K; Huang, Tao; Songkiatisak, Preeyaporn; Warren, Seth; Xu, Xiao-Hong Nancy

    2018-03-26

    ATP-binding cassette (ABC) membrane transporters serve as self-defense transport apparatus in many living organisms and they can selectively extrude a wide variety of substrates, leading to multidrug resistance (MDR). The detailed molecular mechanisms remain elusive. Single nanoparticle plasmonic spectroscopy highly depends upon their sizes, shapes, chemical and surface properties. In our previous studies, we have used the size-dependent plasmonic spectra of single silver nanoparticles (Ag NPs) to study the real-time efflux kinetics of the ABC (BmrA) transporter and MexAB-OprM transporter in single live cells (Gram-positive and Gram-negative bacterium), respectively. In this study, we prepared and used purified, biocompatible and stable (non-aggregated) gold nanoparticles (Au NPs) (12.4 ± 0.9 nm) to study the efflux kinetics of single BmrA membrane transporters of single live Bacillus subtillis cells, aiming to probe chemical dependent efflux functions of BmrA transporters and their potential chemical sensing capability. Similar to those observed using Ag NPs, accumulation of the intracellular Au NPs in single live cells (WT and ΔBmrA) highly depends upon the cellular expression of BmrA and the NP concentration (0.7 and 1.4 nM). The lower accumulation of intracellular Au NPs in WT (normal expression of BmrA) than ΔBmrA (deletion of bmrA) indicates that BmrA extrudes the Au NPs out of the WT cells. The accumulation of Au NPs in the cells increases with NP concentration, suggesting that the Au NPs most likely passively diffuse into the cells, similar to antibiotics. The result demonstrates that such small Au NPs can serve as imaging probes to study the efflux function of the BmrA membrane transporter in single live cells. Furthermore, the dependence of the accumulation rate of intracellular Au NPs in single live cells upon the expression of BmrA and the concentration of the NPs is about twice higher than that of the same sized Ag NPs. This interesting finding

  20. Wetting of alkanes on water

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, E.; Bonn, D.; Meunier, J.; Shahidzadeh, N. [Ecole Normale Superieure, Laboratoire de Physique Statistique, 24 rue Lhomond, 75231, Cedex 05 Paris (France); Broseta, D.; Ragil, K. [Institut Francais du Petrole, 1-4 avenue de Bois Preau, 92852 Rueil-Malmaison Cedex (France); Dobbs, H.; Indekeu, J.O. [Katholieke Universiteit Leuven, Laboratorium voor Vaste-Stoffysica en Magnetisme, B-3001 Leuven (Belgium)

    2002-04-01

    The wetting behavior of oil on water (or brine) has important consequences for the transport properties of oil in water-containing porous reservoirs, and consequently for oil recovery. The equilibrium wetting behavior of model oils composed of pure alkanes or alkane mixtures on brine is reviewed in this paper. Intermediate between the partial wetting state, in which oil lenses coexist on water with a thin film of adsorbed alkane molecules, and the complete wetting state, in which a macroscopically thick oil layer covers the water, these systems display a third, novel wetting state, in which oil lenses coexist with a mesoscopic (a few-nanometers-thick) oil film. The nature and location of the transitions between these wetting regimes depend on oil and brine compositions, temperature and pressure.

  1. The role of nano-particles in the field of thermal spray coating technology

    Science.gov (United States)

    Siegmann, Stephan; Leparoux, Marc; Rohr, Lukas

    2005-06-01

    Nano-particles play not only a key role in recent research fields, but also in the public discussions about health and safety in nanotechnology. Nevertheless, the worldwide activities in nano-particles research increased dramatically during the last 5 to 10 years. There are different potential routes for the future production of nano-particles at large scale. The main directions envisaged are mechanical milling, wet chemical reactions or gas phase processes. Each of the processes has its specific advantages and limitations. Mechanical milling and wet chemical reactions are typically time intensive and batch processes, whereas gas phase productions by flames or plasma can be carried out continuously. Materials of interest are mainly oxide ceramics, carbides, nitrides, and pure metals. Nano-ceramics are interesting candidates for coating technologies due to expected higher coating toughness, better thermal shock and wear resistance. Especially embedded nano-carbides and-nitrides offer homogenously distributed hard phases, which enhance coatings hardness. Thermal spraying, a nearly 100 years old and world wide established coating technology, gets new possibilities thanks to optimized, nano-sized and/or nano-structured powders. Latest coating system developments like high velocity flame spraying (HVOF), cold gas deposition or liquid suspension spraying in combination with new powder qualities may open new applications and markets. This article gives an overview on the latest activities in nano-particle research and production in special relation to thermal spray coating technology.

  2. Modeling TiO2 nanoparticle phototoxicity: The importance of chemical concentration, ultraviolet radiation intensity, and time

    Science.gov (United States)

    Toxicity of TiO2 nanoparticles (nano-TiO2) to aquatic organisms can be greatly increased upon the exposure to ultraviolet radiation (UV). This phenomenon has received some attention for pelagic species, however, investigations of nano-TiO2 phototoxicity in benthic organisms are s...

  3. Physical-chemical properties of nanocomposites based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and titanium dioxide nanoparticles

    Science.gov (United States)

    Braga, Natália F.; da Silva, Ana Paula; Moraes Arantes, Tatiane; Lemes, Ana Paula; Cristovan, Fernando Henrique

    2018-01-01

    Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was reinforced with titanium dioxide (TiO2) in concentrations of 1.0%, 2.5% and 5.0% (m/m) to produce nanocomposites by the solvent casting technique. TiO2 was synthesized by a hydrothermal treatment to produce nanoparticles. The nanostructure of the nanoparticles was studied by x-ray diffraction analysis (XRD) and transmission electron microscopy (TEM). The XRD confirmed TiO2 crystalline nanoparticles, with a mixture of anatase and rutile phases. Through TEM analysis, the formation of TiO2 nanorod agglomerates with an average diameter and length of 40 and 12 nm, respectively, was observed. The thermal and mechanical properties of the pure PHBV and nanocomposite films were characterized by differential scanning calorimetry (DSC) and dynamic mechanical analysis. The DSC analysis showed that the glass transition temperature decreased with the inclusion of TiO2 in the PHBV matrix in relation to pure PHBV. The results of biodegradation assays for the PHBV and nanocomposites in an aqueous medium and in soil showed morphological and structural changes for all samples, indicating a high biodegradation rate for this material. The most important conclusion is that the biodegradation of the PHBV was not affected by the addition of nanoparticles, thus enabling the use of nanocomposites in applications requiring biodegradable materials.

  4. Wetting of cholesteric liquid crystals.

    Science.gov (United States)

    Silvestre, Nuno M; Figueirinhas Pereira, Maria Carolina; Bernardino, Nelson R; Telo da Gama, Margarida M

    2016-02-01

    We investigate theoretically the wetting properties of cholesteric liquid crystals at a planar substrate. If the properties of substrate and of the interface are such that the cholesteric layers are not distorted, the wetting properties are similar to those of a nematic liquid crystal. If, on the other hand, the anchoring conditions force the distortion of the liquid crystal layers the wetting properties are altered, the free cholesteric-isotropic interface is non-planar and there is a layer of topological defects close to the substrate. These deformations can either promote or hinder the wetting of the substrate by a cholesteric, depending on the properties of the cholesteric liquid crystal.

  5. Wetting front instability in an initially wet unsaturated fracture

    International Nuclear Information System (INIS)

    Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

    1993-01-01

    Experimental results exploring gravity-driven wetting from instability in a pre-wetted, rough-walled analog fractures such as those at Yucca Mountain are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

  6. Wetting front instability in an initially wet unsaturated fracture

    International Nuclear Information System (INIS)

    Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

    1992-01-01

    Experimental results exploring gravity-driven wetting front instability in a pre-wetted, rough-walled analog fracture are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

  7. Azadirachta indica plant-assisted green synthesis of Mn3O4 nanoparticles: Excellent thermal catalytic performance and chemical sensing behavior.

    Science.gov (United States)

    Sharma, Jitendra Kumar; Srivastava, Pratibha; Ameen, Sadia; Akhtar, M Shaheer; Singh, Gurdip; Yadava, Sudha

    2016-06-15

    The leaf extract of Azadirachta indica (Neem) plant was utilized as reducing agent for the green synthesis of Mn3O4 nanoparticles (NPs). The crystalline analysis demonstrated the typical tetragonal hausmannite crystal structure of Mn3O4, which confirmed the formation of Mn3O4 NPs without the existence of other oxides. Green synthesized Mn3O4 NPs were applied for the catalytic thermal decomposition of ammonium perchlorate (AP) and as working electrode for fabricating the chemical sensor. The excellent catalytic effect for the thermal decomposition of AP was observed by decreasing the decomposition temperature by 175 °C with single decomposing step. The fabricated chemical sensor based on green synthesized Mn3O4 NPs displayed high, reliable and reproducible sensitivity of ∼569.2 μA mM(-1) cm(-2) with reasonable limit of detection (LOD) of ∼22.1 μM and the response time of ∼10 s toward the detection of 2-butanone chemical. A relatively good linearity in the ranging from ∼20 to 160 μM was detected for Mn3O4 NPs electrode based 2-butanone chemical sensor. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Fabrication of superhydrophobic surfaces based on ZnO-PDMS nanocomposite coatings and study of its wetting behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Chakradhar, R.P.S., E-mail: chakra@nal.res.in [Surface Engineering Division, National Aerospace Laboratories (CSIR), Bangalore 560017 (India); Kumar, V. Dinesh [Surface Engineering Division, National Aerospace Laboratories (CSIR), Bangalore 560017 (India); Rao, J.L. [Department of Physics, S.V. University, Tirupathi 517502 (India); Basu, Bharathibai J., E-mail: bharathi@nal.res.in [Surface Engineering Division, National Aerospace Laboratories (CSIR), Bangalore 560017 (India)

    2011-08-01

    Superhydrophobic surfaces based on ZnO-PDMS nanocomposite coatings are demonstrated by a simple, facile, time-saving, wet chemical route. ZnO nanopowders with average particle size of 14 nm were synthesized by a low temperature solution combustion method. Powder X-ray diffraction results confirm that the nanopowders exhibit hexagonal wurtzite structure and belong to space group P63mc. Field emission scanning electron micrographs reveal that the nanoparticles are connected to each other to make large network systems consisting of hierarchical structure. The as formed ZnO coating exhibits wetting behaviour with Water Contact Angle (WCA) of {approx}108{sup o}, however on modification with polydimethylsiloxane (PDMS), it transforms to superhydrophobic surface with measured contact and sliding angles for water at 155{sup o} and less than 5{sup o} respectively. The surface properties such as surface free energy ({gamma}{sub p}), interfacial free energy ({gamma}{sub pw}), and the adhesive work (W{sub pw}) were evaluated. Electron paramagnetic resonance (EPR) studies on superhydrophobic coatings revealed that the surface defects play a major role on the wetting behaviour. Advantages of the present method include the cheap and fluorine-free raw materials, environmentally benign solvents, and feasibility for applying on large area of different substrates.

  9. Fabrication of superhydrophobic surfaces based on ZnO-PDMS nanocomposite coatings and study of its wetting behaviour

    Science.gov (United States)

    Chakradhar, R. P. S.; Kumar, V. Dinesh; Rao, J. L.; Basu, Bharathibai J.

    2011-08-01

    Superhydrophobic surfaces based on ZnO-PDMS nanocomposite coatings are demonstrated by a simple, facile, time-saving, wet chemical route. ZnO nanopowders with average particle size of 14 nm were synthesized by a low temperature solution combustion method. Powder X-ray diffraction results confirm that the nanopowders exhibit hexagonal wurtzite structure and belong to space group P63 mc. Field emission scanning electron micrographs reveal that the nanoparticles are connected to each other to make large network systems consisting of hierarchical structure. The as formed ZnO coating exhibits wetting behaviour with Water Contact Angle (WCA) of ˜108°, however on modification with polydimethylsiloxane (PDMS), it transforms to superhydrophobic surface with measured contact and sliding angles for water at 155° and less than 5° respectively. The surface properties such as surface free energy ( γp), interfacial free energy ( γpw), and the adhesive work ( Wpw) were evaluated. Electron paramagnetic resonance (EPR) studies on superhydrophobic coatings revealed that the surface defects play a major role on the wetting behaviour. Advantages of the present method include the cheap and fluorine-free raw materials, environmentally benign solvents, and feasibility for applying on large area of different substrates.

  10. Fabrication of superhydrophobic surfaces based on ZnO-PDMS nanocomposite coatings and study of its wetting behaviour

    International Nuclear Information System (INIS)

    Chakradhar, R.P.S.; Kumar, V. Dinesh; Rao, J.L.; Basu, Bharathibai J.

    2011-01-01

    Superhydrophobic surfaces based on ZnO-PDMS nanocomposite coatings are demonstrated by a simple, facile, time-saving, wet chemical route. ZnO nanopowders with average particle size of 14 nm were synthesized by a low temperature solution combustion method. Powder X-ray diffraction results confirm that the nanopowders exhibit hexagonal wurtzite structure and belong to space group P63mc. Field emission scanning electron micrographs reveal that the nanoparticles are connected to each other to make large network systems consisting of hierarchical structure. The as formed ZnO coating exhibits wetting behaviour with Water Contact Angle (WCA) of ∼108 o , however on modification with polydimethylsiloxane (PDMS), it transforms to superhydrophobic surface with measured contact and sliding angles for water at 155 o and less than 5 o respectively. The surface properties such as surface free energy (γ p ), interfacial free energy (γ pw ), and the adhesive work (W pw ) were evaluated. Electron paramagnetic resonance (EPR) studies on superhydrophobic coatings revealed that the surface defects play a major role on the wetting behaviour. Advantages of the present method include the cheap and fluorine-free raw materials, environmentally benign solvents, and feasibility for applying on large area of different substrates.

  11. Dose of radiation enhancement, using silver nanoparticles in a human tissue equivalent gel dosimeter.

    Science.gov (United States)

    Hassan, Muhammad; Waheed, Muhammad Mohsin; Anjum, Muhammad Naeem

    2016-01-01

    To quantify the radiation dose enhancement in a human tissue-equivalent polymer gel impregnated with silver nanoparticles. The case-control study was conducted at the Bahawalpur Institute of Nuclear Medicine and Oncology, Bahawalpur, Pakistan, in January 2014. Silver nanoparticles used in this study were prepared by wet chemical method. Polymer gel was prepared by known quantity of gelatine, methacrylic acid, ascorbic acid, copper sulphate pentahydrate, hydroquinone and water. Different concentrations of silver nanoparticles were added to the gel during its cooling process. The gel was cooled in six plastic vials of 50ml each. Two vials were used as a control sample while four vials were impregnated with silver nanoparticles. After 22 hours, the vials were irradiated with gamma rays by aCobalt-60 unit. Radiation enhancement was assessed by taking magnetic resonance images of the vials. The images were analysed using Image J software. The dose enhancement factor was 24.17% and 40.49% for 5Gy and 10Gy dose respectively. The dose enhancement factor for the gel impregnated with 0.10mM silver nanoparticles was 32.88% and 51.98% for 5Gy and 10Gy dose respectively. The impregnation of a tissue-equivalent gel with silver nanoparticles resulted in dose enhancement and this effect was magnified up to a certain level with the increase in concentration of silver nanoparticles.

  12. Exposure to wet work in working Australians.

    Science.gov (United States)

    Keegel, Tessa G; Nixon, Rosemary L; LaMontagne, Anthony D

    2012-02-01

    The Australian National Hazard Exposure Worker Surveillance (NHEWS) Survey 2008 was a cross-sectional survey undertaken by Safe Work Australia to inform the development of exposure prevention initiatives for occupational disease. This is a descriptive study of workplace exposures. To assess the occupational and demographic characteristics of workers reporting exposure to wet work. Computer-assisted telephone interviews were conducted with 4500 workers. Two wet work exposure outcomes (frequent washing of hands and duration of time spent at work with the hands immersed in liquids) were analysed. The response rate for the study was 42.3%. For hand-washing, 9.8% [95% confidence interval (CI) 8.9-10.7] reported washing their hands more than 20 times per day. For immersion of hands in liquids, 4.5% (95% CI 3.9-5.1) reported immersion for more than 2 hr per day. Females were more likely to report exposure to frequent hand-washing than males [odds ratio (OR) 1.97, 95% CI 1.49-2.61]. Workers in the lowest occupational skill level jobs were more likely to report increased exposure to hands immersed in liquids than those in the highest (OR 6.41, 95% CI 3.78-10.88). Workers reporting skin exposure to chemicals were more likely to report exposure to hand-washing (OR 3.68, 95% CI 2.91-4.66) and immersion of the hands in liquids (OR 4.09, 95% CI 2.92-5.74). Specific groups of workers reported high levels of exposure to wet work. There were differences between the profiles of workers reporting frequent hand-washing and workers reporting increased duration of exposure to hands immersed in liquids. We also found a high correlation between wet work and chemical exposure. © 2011 John Wiley & Sons A/S.

  13. Wetting-dewetting films: the role of structural forces.

    Science.gov (United States)

    Nikolov, Alex; Wasan, Darsh

    2014-04-01

    The liquid wetting and dewetting of solids are ubiquitous phenomena that occur in everyday life. Understanding the nature of these phenomena is beneficial for research and technological applications. However, despite their importance, the phenomena are still not well understood because of the nature of the substrate's surface energy non-ideality and dynamics. This paper illustrates the mechanisms and applications of liquid wetting and dewetting on hydrophilic and hydrophobic substrates. We discuss the classical understanding and application of wetting and film stability criteria based on the Frumkin-Derjaguin disjoining pressure model. The roles of the film critical thickness and capillary pressure on the film instability based on the disjoining pressure isotherm are elucidated, as are the criteria for stable and unstable wet films. We consider the film area in the model for the film stability and the applicable experiments. This paper also addresses the two classic film instability mechanisms for suspended liquid films based on the conditions of the free energy criteria originally proposed by de Vries (nucleation hole formation) and Vrij-Scheludko (capillary waves vs. van der Waals forces) that were later adapted to explain dewetting. We include a discussion of the mechanisms of nanofilm wetting and dewetting on a solid substrate based on nanoparticles' tendency to form a 2D layer and 2D inlayer in the film under the wetting film's surface confinement. We also present our view on the future of wetting-dewetting modeling and its applications in developing emerging technologies. We believe the review and analysis presented here will benefit the current and future understanding of the wetting-dewetting phenomena, as well as aid in the development of novel products and technologies. © 2013.

  14. Temperature-dependent structure of Tb-doped magnetite nanoparticles

    International Nuclear Information System (INIS)

    Rice, Katherine P.; Russek, Stephen E.; Shaw, Justin M.; Usselman, Robert J.; Evarts, Eric R.; Silva, Thomas J.; Nembach, Hans T.; Geiss, Roy H.; Arenholz, Elke; Idzerda, Yves U.

    2015-01-01

    High quality 5 nm cubic Tb-doped magnetite nanoparticles have been synthesized by a wet-chemical method to investigate tailoring of magnetic properties for imaging and biomedical applications. We show that the Tb is incorporated into the octahedral 3+ sites. High-angle annular dark-field microscopy shows that the dopant is well-distributed throughout the particle, and x-ray diffraction measurements show a small lattice parameter shift with the inclusion of a rare-earth dopant. Magnetization and x-ray magnetic circular dichroism data indicate that the Tb spins are unpolarized and weakly coupled to the iron spin lattice at room temperature, and begin to polarize and couple to the iron oxide lattice at temperatures below 50 K. Broadband ferromagnetic resonance measurements show no increase in magnetic damping at room temperature for Tb-doped nanoparticles relative to undoped nanoparticles, further confirming weak coupling between Fe and Tb spins at room temperature. The Gilbert damping constant, α, is remarkably low for the Tb-doped nanoparticles, with α = 0.024 ± 0.003. These nanoparticles, which have a large fixed moment, a large fluctuating moment and optically active rare-earth elements, are potential high-relaxivity T1 and T2 MRI agents with integrated optical signatures

  15. Temperature-dependent structure of Tb-doped magnetite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Rice, Katherine P.; Russek, Stephen E., E-mail: stephen.russek@nist.gov; Shaw, Justin M.; Usselman, Robert J.; Evarts, Eric R.; Silva, Thomas J.; Nembach, Hans T. [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Geiss, Roy H. [Colorado State University, Fort Collins, Colorado 80523 (United States); Arenholz, Elke [Lawrence Berkeley National Laboratory, Advanced Light Source, Berkeley, California 94720 (United States); Idzerda, Yves U. [Department of Physics, Montana State University, Bozeman, Montana 59717 (United States)

    2015-02-09

    High quality 5 nm cubic Tb-doped magnetite nanoparticles have been synthesized by a wet-chemical method to investigate tailoring of magnetic properties for imaging and biomedical applications. We show that the Tb is incorporated into the octahedral 3+ sites. High-angle annular dark-field microscopy shows that the dopant is well-distributed throughout the particle, and x-ray diffraction measurements show a small lattice parameter shift with the inclusion of a rare-earth dopant. Magnetization and x-ray magnetic circular dichroism data indicate that the Tb spins are unpolarized and weakly coupled to the iron spin lattice at room temperature, and begin to polarize and couple to the iron oxide lattice at temperatures below 50 K. Broadband ferromagnetic resonance measurements show no increase in magnetic damping at room temperature for Tb-doped nanoparticles relative to undoped nanoparticles, further confirming weak coupling between Fe and Tb spins at room temperature. The Gilbert damping constant, α, is remarkably low for the Tb-doped nanoparticles, with α = 0.024 ± 0.003. These nanoparticles, which have a large fixed moment, a large fluctuating moment and optically active rare-earth elements, are potential high-relaxivity T1 and T2 MRI agents with integrated optical signatures.

  16. Synthesis of Copper Nanoparticles Coated with Nitrogen Ligands

    Directory of Open Access Journals (Sweden)

    Rubén Sierra-Ávila

    2014-01-01

    Full Text Available The synthesis of copper nanoparticles was studied by wet chemical methods using copper sulfate pentahydrate (CuSO4·5H2O and nitrogen ligands allylamine (AAm and polyallylamine (PAAm as stabilizers. The results suggest that the use of these ligands leads to the exclusive formation of metallic copper nanoparticles (Cu-NPs. The use of partially crosslinked polyallylamine (PAAmc leads to nanoparticles (NPs with low yields and high coating content, while linear PAAm leads to NPs with high yields and low coating content. The chemical composition of the particles was determined by XRD and average particle diameters were determined by the Debye-Scherrer equation. TGA analysis provided evidence of the content and thermal stability of the coating on the nanoparticles and PAAm. The morphology, particle size distribution, and presence of PAAm coating were observed through TEM. The use of AAm in the synthesis of NPs could be a good alternative to reduce costs. By using TGA, TEM, and DSC techniques, it was determined that synthesized NPs with AAm presented a coating with similar characteristics to NPs with PAAm, suggesting that AAm underwent polymerization during the synthesis.

  17. Wet Mars, Dry Mars

    Science.gov (United States)

    Fillingim, M. O.; Brain, D. A.; Peticolas, L. M.; Yan, D.; Fricke, K. W.; Thrall, L.

    2012-12-01

    The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and even give us clues to the atmospheric history of these planets. This poster highlights the third in a series of presentations that target school-age audiences with the overall goal of helping the audience visualize planetary magnetic field and understand how they can impact the climatic evolution of a planet. Our first presentation, "Goldilocks and the Three Planets," targeted to elementary school age audiences, focuses on the differences in the atmospheres of Venus, Earth, and Mars and the causes of the differences. The second presentation, "Lost on Mars (and Venus)," geared toward a middle school age audience, highlights the differences in the magnetic fields of these planets and what we can learn from these differences. Finally, in the third presentation, "Wet Mars, Dry Mars," targeted to high school age audiences and the focus of this poster, the emphasis is on the long term climatic affects of the presence or absence of a magnetic field using the contrasts between Earth and Mars. These presentations are given using visually engaging spherical displays in conjunction with hands-on activities and scientifically accurate 3D models of planetary magnetic fields. We will summarize the content of our presentations, discuss our lessons learned from evaluations, and show (pictures of) our hands-on activities and 3D models.

  18. A Mössbauer study of the chemical stability of iron oxide nanoparticles in PMMA and PVB beads

    DEFF Research Database (Denmark)

    Chen, Wei; Mørup, Steen; Hansen, Mikkel Fougt

    2008-01-01

    We have prepared magnetic beads consisting of iron oxide nanoparticles in a polymethyl methacrylate (PMMA) and a polyvinyl butyral (PVB) matrix. High-field Mossbauer studies show that the particles have an almost perfect collinear spin structure and magnetization measurements show that they are s...... transformed to maghemite. The PVB beads are hydrophilic and biocompatible and are therefore well suited for applications in medicine and biology....

  19. A soft chemical route to the synthesis of BiFeO{sub 3} nanoparticles with enhanced magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Mehedi, E-mail: mhrizvi@gce.buet.ac.bd [Department of Glass and Ceramic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh (India); Islam, Md. Fakhrul, E-mail: fislam@gce.buet.ac.bd [Department of Glass and Ceramic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh (India); Mahbub, Rubayyat, E-mail: rubayyatm@gce.buet.ac.bd [Department of Glass and Ceramic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh (India); Hossain, Md. Sarowar, E-mail: sakil_phy@yahoo.com [S.N. Bose National Centre for Basic Sciences, Salt Lake City, Kolkata, West Bengal 700098 (India); Hakim, M.A., E-mail: hakim.akm@gmail.com [Department of Glass and Ceramic Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh (India)

    2016-01-15

    Highlights: • Pure BiFeO{sub 3} nanoparticles have been synthesized at relatively low temperature. • Decomposition behavior of BiFeO{sub 3} precursor gel is investigated. • Particle size dependent magnetic properties have been confirmed. • Greatly improved magnetization is observed for BiFeO{sub 3} nanostructure. - Abstract: Utilization of BiFeO{sub 3} (BFO) into modern device applications is restricted by its very low magnetic moments and high leakage current. Enhancement in magnetization is a real challenge for multiferroic BFO in the context of device miniaturization and high density information storage system. In this study a significant improvement in magnetization has been recorded for BFO nanoparticles, exploiting the beneficial effect of size confinement. BFO nanoparticles with different size in the range of 21–68 nm are synthesized via modified Pechini sol–gel approach followed by leaching with acetic acid. X-ray diffraction result confirms pure and well crystallized BFO annealed at temperature lower than 600 °C, compared to more than 800 °C for the traditional solid-state sintering process. A strong size-dependent magnetization which increases with decreasing particle size is confirmed with a value of 1.4 emu/g for 40 nm particles in contrast to 7.5 emu/g for 21 nm particles.

  20. Metal oxide nanoparticle mediated enhanced Raman scattering and its use in direct monitoring of interfacial chemical reactions.

    Science.gov (United States)

    Li, Li; Hutter, Tanya; Finnemore, Alexander S; Huang, Fu Min; Baumberg, Jeremy J; Elliott, Stephen R; Steiner, Ullrich; Mahajan, Sumeet

    2012-08-08

    Metal oxide nanoparticles (MONPs) have widespread usage across many disciplines, but monitoring molecular processes at their surfaces in situ has not been possible. Here we demonstrate that MONPs give highly enhanced (×10(4)) Raman scattering signals from molecules at the interface permitting direct monitoring of their reactions, when placed on top of flat metallic surfaces. Experiments with different metal oxide materials and molecules indicate that the enhancement is generic and operates at the single nanoparticle level. Simulations confirm that the amplification is principally electromagnetic and is a result of optical modulation of the underlying plasmonic metallic surface by MONPs, which act as scattering antennae and couple light into the confined region sandwiched by the underlying surface. Because of additional functionalities of metal oxides as magnetic, photoelectrochemical and catalytic materials, enhanced Raman scattering mediated by MONPs opens up significant opportunities in fundamental science, allowing direct tracking and understanding of application-specific transformations at such interfaces. We show a first example by monitoring the MONP-assisted photocatalytic decomposition reaction of an organic dye by individual nanoparticles.

  1. Multi-functionality Redefined with Colloidal Carotene Carbon Nanoparticles for Synchronized Chemical Imaging, Enriched Cellular Uptake and Therapy

    Science.gov (United States)

    Misra, Santosh K.; Mukherjee, Prabuddha; Chang, Huei-Huei; Tiwari, Saumya; Gryka, Mark; Bhargava, Rohit; Pan, Dipanjan

    2016-07-01

    Typically, multiplexing high nanoparticle uptake, imaging, and therapy requires careful integration of three different functions of a multiscale molecular-particle assembly. Here, we present a simpler approach to multiplexing by utilizing one component of the system for multiple functions. Specifically, we successfully synthesized and characterized colloidal carotene carbon nanoparticle (C3-NP), in which a single functional molecule served a threefold purpose. First, the presence of carotene moieties promoted the passage of the particle through the cell membrane and into the cells. Second, the ligand acted as a potent detrimental moiety for cancer cells and, finally, the ligands produced optical contrast for robust microscopic detection in complex cellular environments. In comparative tests, C3-NP were found to provide effective intracellular delivery that enables both robust detection at cellular and tissue level and presents significant therapeutic potential without altering the mechanism of intracellular action of β-carotene. Surface coating of C3 with phospholipid was used to generate C3-Lipocoat nanoparticles with further improved function and biocompatibility, paving the path to eventual in vivo studies.

  2. Raman scattering studies on PEG functionalized hydroxyapatite nanoparticles

    Science.gov (United States)

    Yamini, D.; Devanand Venkatasubbu, G.; Kumar, J.; Ramakrishnan, V.

    2014-01-01

    The pure hydroxyapatite (HAP) nanoparticles (NPs) have been synthesized by wet chemical precipitation method. Raman spectral measurements have been made for pure HAP, pure Polyethylene glycol (PEG) 6000 and PEG coated HAP in different mass ratios (sample 1, sample 2 and sample 3). The peaks observed in Raman spectrum of pure HAP and the XRD pattern have confirmed the formation of HAP NPs. Vibrational modes have been assigned for pure HAP and pure PEG 6000. The observed variation in peak position of Raman active vibrationa