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Sample records for facile hydrothermal method

  1. A facile single injection Hydrothermal method for the synthesis of thiol capped CdTe Quantum dots as light harvesters

    Energy Technology Data Exchange (ETDEWEB)

    Jai Kumar, B.; Sumanth Kumar, D.; Mahesh, H.M., E-mail: hm_mahesh@rediffmail.com

    2016-10-15

    A facile, Single Injection Hydrothermal (SIH) method has been developed to synthesize high quality 3-Mercaptopropionic Acid (MPA) stabilized aqueous CdTe QDs, entirely in ambient environment. The synthesis protocol eliminates the use of inert atmosphere for reducing elemental Tellurium powder to Te precursor avoiding the oxidation of Te powder. The XRD result revealed that the synthesized QDs are in cubic zincblende type crystalline structure, without signature of Te oxidation. FTIR spectra have confirmed the attachment of short chained organic compound MPA to the surface of QDs by covalent bond. The Quantum confinement effect was clearly evident by shift in Longitudinal Optic (LO) peak of Raman spectra and absorption peak wavelength with respect to bulk CdTe materials. The optical direct band gap energy of CdTe QDs is between 3.63 eV to 1.96 eV and QDs size below 6 nm, confirm the QDs are well under strong Quantum confinement regime. Also, photoluminescence spectra depict a stable and high luminescence emission from green to dark red color. All these results corroborate that the synthesis of CdTe QDs procedure is very advantageous and present a simple, economical and easily up scalable method for large scale production.

  2. Formation Mechanism and Gas-Sensing Performance of La/ZnO Nanoplates Synthesized by a Facile Hydrothermal Method

    Science.gov (United States)

    Li, Yan; Chen, Li-Li; Lian, Xiao-Xue; Li, Jiao

    2018-03-01

    La/ZnO nanoplates were successfully synthesized by a facile hydrothermal method. The structure and morphology of the products were characterized using x-ray diffraction and scanning electron microscopy. The gas-sensing properties of the as-prepared La/ZnO were also tested with a series of target gases, and a possible gas sensing mechanism was discussed. The results show that the as-prepared La/ZnO nanoparticles are mainly composde of a wurtzite ZnO and a little La2O3 phase with face-centered structure, showing a uniform plate-like morphology with a thickness of about 50 nm. The La/ZnO nanoplate-based sensors display a significantly better sensing performance than pure ZnO for the detection of acetone and ethanol. The 3 mol.% La/ZnO sensor shows high sensitivity (127) to 200 ppm acetone at a low working temperature (330°C), and 120-200 ppm ethanol at 300°C. Moreover, its response and recovery time for acetone and ethanol were 3 s and 4 s, 18 s and 11 s, respectively. This work demonstrates that La/ZnO nanoplate-based sensors have potential applications as practical sensors for acetone and ethanol.

  3. Facile hydrothermal synthesis of CeO 2 nanopebbles

    Indian Academy of Sciences (India)

    Cerium oxide (CeO2) nanopebbles have been synthesized using a facile hydrothermal method. X-ray diffraction pattern (XRD) and transmission electron microscopy analyses confirm the presence of CeO2 nanopebbles. XRD shows the formation of cubic fluorite CeO2 and the average particle size estimated from the ...

  4. Nanocrystalline GaSbO{sub 4} with high surface area prepared via a facile hydrothermal method and its photocatalytic activity study

    Energy Technology Data Exchange (ETDEWEB)

    Fu Yanghe; Xue Hun; Qin Meng; Liu Ping; Fu Xianzhi [Research Institute of Photocatalysis, Fujian Provincial Key Laboratory of Photocatalysis - State Key Laboratory Breeding Base, Fuzhou University, Fuzhou 350002 (China); Li Zhaohui, E-mail: zhaohuili1969@yahoo.com [Research Institute of Photocatalysis, Fujian Provincial Key Laboratory of Photocatalysis - State Key Laboratory Breeding Base, Fuzhou University, Fuzhou 350002 (China)

    2012-05-05

    Graphical abstract: Nanocrystalline GaSbO{sub 4} prepared via a facile hydrothermal method possesses large specific surface area and exhibits photocatalytic activity for the degradations of salicylic acid and acetone. Highlights: Black-Right-Pointing-Pointer Facile hydrothermal method to nanocrystalline GaSbO{sub 4} with large surface area. Black-Right-Pointing-Pointer GaSbO{sub 4} shows photocatalytic activity for the degradations of salicylic acid and acetone. Black-Right-Pointing-Pointer The photocatalytic mechanism of GaSbO{sub 4} was proposed based on the ESR result. - Abstract: Nanocrystalline GaSbO{sub 4} with small particle size and large BET specific area was successfully prepared via a facile hydrothermal method from Sb{sub 2}O{sub 5}. The influence of the reaction pH on the formation of the final product was investigated. The obtained sample was characterized by X-ray diffraction (XRD), N{sub 2}-sorption BET surface area, UV-vis diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM). The photocatalytic activity for the degradations of salicylic acid and acetone over nanocrystalline GaSbO{sub 4} under UV irradiations was for the first time revealed. Based on the electron spin resonance (ESR) result, the reactive species involved in the photocatalytic reaction over nanocrytalline GaSbO{sub 4} are determined to be HO{center_dot} and O{sub 2}{sup -}{center_dot}. The photocatalytic mechanism of GaSbO{sub 4} was proposed.

  5. A facile one-pot hydrothermal method to prepare europium-doped titania hollow phosphors and their sensitized luminescence properties

    Energy Technology Data Exchange (ETDEWEB)

    Feng Xuan; Yang Ling; Zhang Nianchun [Department of Chemistry and Institute of Nanochemistry, Jinan University, 601 Western Huangpu Road, Guangzhou 510632 (China); Liu Yingliang, E-mail: tliuyl@jnu.edu.c [Department of Chemistry and Institute of Nanochemistry, Jinan University, 601 Western Huangpu Road, Guangzhou 510632 (China)

    2010-09-17

    Research highlights: {yields} The strongest emission intensity was observed with TiO{sub 2}:Eu{sub 0.2} hollow spheres and TiO{sub 2}:Eu{sub 0.2} hollow spheres calcining at 550 {sup o}C. Moreover, the strongest excitation of TiO{sub 2}:Eu{sub 0.2} hollow spheres transferred from 400 to 500 {sup o}C and the effective nonradiative energy transfer from the TiO{sub 2} hollow spheres host matrix to Eu{sup 3+} ions crystal field states was realized due to changes of crystalline field in the environment around Eu{sup 3+} ions occupying Ti{sup 4+} sites. The proposed energy transfer mechanism was that UV light is absorbed in the band of TiO{sub 2} hollow spheres crystal and then the energy is relaxed to the defect states of TiO{sub 2} host. The energy can transfer to the crystal states of Eu{sup 3+} ions ({sup 7}F{sub j}, j = 0, 1, 2, 3 and 4), which results in efficient photoluminescence. The fluorescent intensity of TiO{sub 2}:Eu{sub 0.2} hollow spheres was 2.2 times as strong as that of TiO{sub 2}:Eu{sub 0.2} bulk material. - Abstract: Monodisperse europium-activated titania hollow phosphors had been synthesized by a facile one-pot hydrothermal method using carbon spheres as hard templates. Samples were characterized by X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectrometer and photoluminescence spectrum. The strongest emission intensity was observed with TiO{sub 2}:Eu{sub 0.2} hollow spheres and TiO{sub 2}:Eu{sub 0.2} hollow spheres calcining at 550 {sup o}C. Moreover, the strongest excitation of TiO{sub 2}:Eu{sub 0.2} hollow spheres transferred from 400 to 500 {sup o}C and the effective nonradiative energy transfer from the TiO{sub 2} hollow spheres host matrix to Eu{sup 3+} ions crystal field states was realized due to changes of crystalline field in the environment around Eu{sup 3+} ions occupying Ti{sup 4+} sites. The proposed energy transfer mechanism was that UV light is absorbed in the band

  6. Optical properties and photocatalytic activities of spherical ZnO and flower-like ZnO structures synthesized by facile hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yongling [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Li, Zhongyu, E-mail: zhongyuli@mail.tsinghua.edu.cn [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Changzhou Expansion New Stuff Technology Limited Company, Changzhou 213122 (China); Jilin Institute of Chemical Technology, Jilin 132022 (China); Xu, Song [Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology, School of Petrochemical Engineering, Changzhou University, Changzhou 213164 (China); Han, Dandan; Lu, Dayong [Jilin Institute of Chemical Technology, Jilin 132022 (China)

    2013-10-25

    Highlights: •Spherical ZnO and flower-like ZnO were prepared via a facile hydrothermal method. •The as-prepared ZnO showed high photocatalytic activity over MO degradation. •The as-prepared ZnO were well crystallized and exhibited good optical properties. -- Abstract: Spherical ZnO and flower-like ZnO were prepared by facile hydrothermal method at 180 °C and 160 °C, respectively. The as-prepared samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and UV–vis diffuse reflectance spectroscopy (DRS) spectra. The optical properties of as-prepared sample, such as photoluminescence (PL) spectra and Raman spectra were studied. The photocatalytic activities of the as-prepared ZnO particles were investigated by degrading the methyl orange (MO) under UV light irradiation. The photocatalytic studies showed that the organic pollutants have been almost completely degraded and mineralized after irradiation of the UV light. These results indicated that the as-prepared ZnO particles exhibited good optical properties and high photocatalytic activities.

  7. Characterization and optical properties of pole-like nano-CeO{sub 2} synthesized by a facile hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Leini [School of Physics and Materials Science, Anhui University, Feixi Road, Hefei 230039 (China); Meng, Fanming, E-mail: mrmeng@ahu.edu.cn [School of Physics and Materials Science, Anhui University, Feixi Road, Hefei 230039 (China); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Li, Kangkang [Lab of SoC, Department of Microelectronics, Peking University, Beijing 100871 (China); Lu, Fei [Baotou Research Institute of Rare Earths, Baotou 014030 (China)

    2013-12-01

    CeO{sub 2} nanopoles have been successfully synthesized by a hydrothermal method using CeC{sub l3}·7H{sub 2}O as cerium source, NaOH as mineralizer, and ethylenediamine as complexant. The pole-like nano-CeO{sub 2} was examined by XRD, TEM, XPS, UV–vis, PL, and Raman scattering. The results show that the crystallinity of the nanopoles is not so good, and the main valence of cerium is +4. The estimated direct band gaps are 3.014, 3.099, 2.931, and 2.927 eV for the samples synthesized within 2, 18, 50, and 100 h, respectively. These band gaps are smaller than bulk CeO{sub 2}, oxygen vacancies and Ce{sup 3+} ions result in an effective red shifting of the band gap. The visible luminescence exhibits similar emission peaks of room temperature photoluminescence and the emission intensity increases with the increase of concentration of oxygen vacancies and Ce{sup 3+} ions.

  8. Facile hydrothermal method for synthesizing nitrogen-doped graphene nanoplatelets using aqueous ammonia: dispersion, stability in solvents and thermophysical performances

    Science.gov (United States)

    Shafiah Shazali, Siti; Amiri, Ahmad; Zubir, Mohd. Nashrul Mohd; Rozali, Shaifulazuar; Zakuan Zabri, Mohd; Sabri, Mohd Faizul Mohd

    2018-03-01

    A simple and green approach has been developed to synthesize nitrogen-doped graphene nanoplatelets (N-doped GNPs) for mass production with a very high stability in different solvents e.g. water, ethylene glycol, methanol, ethanol, and 1-hexanol. The strategy is based on mild oxidation of GNPs using hydrogen peroxide and doping with nitrogen using hydrothermal process. The modification of N-doped GNPs was demonstrated by FTIR, TGA, XPS, Raman spectroscopy and high resolution-transmission electron microscope (HRTEM). Further study was carried out by using N-doped GNPs as an additive to prepare different colloidal dispersions. Water-based N-doped GNPs, methanol-based N-doped GNPs, ethanol-based N-doped GNPs, ethylene-glycol based N-doped GNPs and 1-hexanol-based N-doped GNPs dispersions at 0.01 wt.% shown great colloidal stabilities, indicating 17%, 29%, 33%, 18%, and 43% sedimentations after a 15-days period, respectively. The thermophysical properties e.g., viscosity and thermal conductivity of water-based N-doped GNP nanofluids were also evaluated for different weight concentrations of 0.100, 0.075, 0.050, and 0.025 wt.%. Through this, it is found that the obtained dispersions have great potential to be used as working fluids for industrial thermal systems.

  9. Facile template-free hydrothermal synthesis and microstrain ...

    Indian Academy of Sciences (India)

    Administrator

    2009), solar cells (Yuan et al 2011), transparent elec- trodes (Kim et al ... increasing the peak width, intensity and shifting the 2θ peak position. ... Facile template-free hydrothermal synthesis and microstrain measurement of ZnO nanorods. 399.

  10. Synthesis of ZnO nanorod–nanosheet composite via facile hydrothermal method and their photocatalytic activities under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Wai Kian [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Abdul Razak, Khairunisak; Lockman, Zainovia [School of Materials and Mineral Resources, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Kawamura, Go; Muto, Hiroyuki [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Matsuda, Atsunori, E-mail: matsuda@ee.tut.ac.jp [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan)

    2014-03-15

    ZnO composite films consisting of ZnO nanorods and nanosheets were prepared by low-temperature hydrothermal processing at 80 °C on seeded glass substrates. The seed layer was coated on glass substrates by sol–gel dip-coating and pre-heated at 300 °C for 10 min prior to hydrothermal growth. The size of the grain formed after pre-heat treatment was ∼40 nm. A preferred orientation seed layer at the c-axis was obtained, which promoted vertical growth of the ZnO nanorod arrays and formation of the ZnO nanosheets. X-ray diffraction patterns and high-resolution transmission electron microscope (HR-TEM) images confirmed that the ZnO nanorods and nanosheets consist of single crystalline and polycrystalline structures, respectively. Room temperature photoluminescence spectra of the ZnO nanorod–nanosheet composite films exhibited band-edge ultraviolet (UV) and visible emission (blue and green) indicating the formation of ZnO crystals with good crystallinity and are supported by Raman scattering results. The formation of one-dimensional (1D) ZnO nanorod arrays and two-dimensional (2D) ZnO nanosheet films using seeded substrates in a single low-temperature hydrothermal step would be beneficial for realization of device applications that utilize substrates with limited temperature stability. The ZnO nanorods and nanosheets composite structure demonstrated higher photocatalytic activity during degradation of aqueous methylene blue under visible-light irradiation. -- Graphical abstract: Schematic illustration of ZnO nanorod–nanosheet composite structure formation by hydrothermal at low-temperature of 80 °C against time. Highlights: • Novel simultaneous formation of ZnO nanorods and nanosheets composite structure. • Facile single hydrothermal step formation at low-temperature. • Photoluminescence showed ultraviolet and visible emission. • Feasible application on substrates with low temperature stability. • Improved photocatalytic activity under visible

  11. Enhanced microwave absorption properties of MnO{sub 2} hollow microspheres consisted of MnO{sub 2} nanoribbons synthesized by a facile hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yan; Han, Bingqian; Chen, Nan; Deng, Dongyang; Guan, Hongtao [Department of Materials Science and Engineering, Yunnan University, 650091, Kunming (China); Wang, Yude, E-mail: ydwang@ynu.edu.cn [Department of Materials Science and Engineering, Yunnan University, 650091, Kunming (China); Yunnan Province Key Lab of Micro-Nano Materials and Technology, Yunnan University, 650091, Kunming (China)

    2016-08-15

    MnO{sub 2} hollow microspheres consisted of nanoribbons were successfully fabricated via a facile hydrothermal method with SiO{sub 2} sphere templates. The crystal structure, morphology and microwave absorption properties in X and Ku band of the as-synthesized samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and a vector network analyzer. The results show that the three-dimensional (3D) hollow microspheres are assembled by ultra thin and narrow one-dimensional (1D) nanoribbons. A rational process for the formation of hollow microspheres is proposed. The 3D MnO{sub 2} hollow microspheres possess improved dielectric and magnetic properties than the 1D nanoribbons prepared by the same procedures with the absence of SiO{sub 2} hard templates, which are closely related to their special nanostructures. The MnO{sub 2} microspheres also show much better microwave absorption properties in X (8–12 GHz) and Ku (12–18 GHz) microwave band compared with 1D MnO{sub 2} nanoribbons. The minimum reflection loss of −40 dB for hollow microsphere can be observed at 14.2 GHz and reflection loss below −10 dB is 3.5 GHz with a thickness of only 4 mm. The possible mechanism for the enhanced microwave absorption properties is also discussed. - Graphical abstract: MnO{sub 2} hollow microspheres composed of nanoribbons show the excellent microwave absorption properties in X and Ku band. - Highlights: • MnO{sub 2} hollow microspheres consisted of MnO{sub 2} nanoribbons were successfully prepared. • MnO{sub 2} hollow microspheres possess good microwave absorption performances. • The excellent microwave absorption properties are in X and Ku microwave band. • Electromagnetic impedance matching is great contribution to absorption properties.

  12. Hydrothermal optimal power flow using continuation method

    International Nuclear Information System (INIS)

    Raoofat, M.; Seifi, H.

    2001-01-01

    The problem of optimal economic operation of hydrothermal electric power systems is solved using powerful continuation method. While in conventional approach, fixed generation voltages are used to avoid convergence problems, in the algorithm, they are treated as variables so that better solutions can be obtained. The algorithm is tested for a typical 5-bus and 17-bus New Zealand networks. Its capabilities and promising results are assessed

  13. Fabrication of free-standing NiCo2O4 nanoarrays via a facile modified hydrothermal synthesis method and their applications for lithium ion batteries and high-rate alkaline batteries

    International Nuclear Information System (INIS)

    Zheng, Qingyun; Zhang, Xiangyang; Shen, Youming

    2015-01-01

    Graphical abstract: Hydrothermal-synthesized NiCo 2 O 4 nanoflake arrays exhibit porous structure and high capacity as well as good cycling life for lithium ion batteries and alkaline batteries. - Highlights: • Self-supported NiCo 2 O 4 nanoflake arrays are prepared by a hydrothermal method. • NiCo 2 O 4 nanoflake arrays show high capacity and good cycling life. • Porous nanoflake arrays structure is favorable for fast ion/electron transfer. - Abstract: Self-supported NiCo 2 O 4 nanoflake arrays on nickel foam are prepared by a facile hydrothermal method. The obtained NiCo 2 O 4 nanoflakes with thicknesses of ∼25 nm grow vertically to the nickel foam substrate and form an interconnected porous network with pore diameters of 50–500 nm. As anode material of LIBs, the NiCo 2 O 4 nanoflake arrays show a high initial coulombic efficiency of 76%, as well as good cycling stability with a capacity of 880 mAh g −1 at 0.5 A g −1 , and 523 mAh g −1 at 1.5 A g −1 after 50 cycles. As the cathode of alkaline batteries, a high capacity of 95 mAh g −1 is achieved at 2 A g −1 and 94% retention is maintained after 10,000 cycles. The superior electrochemical performance is mainly due to the unique nanoflake arrays structure with large surface area and shorter diffusion length for mass and charge transport

  14. Facile hydrothermal method synthesis of coralline-like Li1.2Mn0.54Ni0.13Co0.13O2 hierarchical architectures as superior cathode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Hou, Xianhua; Huang, Yanling; Ma, Shaomeng; Zou, Xiaoli; Hu, Shejun; Wu, Yuping

    2015-01-01

    Highlights: • A coralline-like Li 1.20 Mn 0.54 Ni 0.13 Co 0.13 O 2 cathode was synthesized by hydrothermal method. • Initial discharge capacity of 250.2 mAh g −1 for the cathode was obtained at 0.1 C. • A high reversible specific capacity of 210.2 mAh g −1 after 100 cycles was acquired. • The high capacity retention of 84.5% was obtained even after 200 cycles at 10 C. - Abstract: A coralline-like lithium-rich layered cathode material with homogeneous composition of Li 1.20 Mn 0.54 Ni 0.13 Co 0.13 O 2 has been successfully synthesized via a facile ethanolamine (EA)-mediated hydrothermal method route, with subsequent calcination at 850 °C. An initial specific discharge capacity of 250.2 mAh g −1 and a reversible specific capacity of 210.2 mAh g −1 after 100 cycles at a constant density of 25 mA g −1 (1 C = 250 mA g −1 ) are acquired. Even at 10 C, it still delivers a discharge capacity of approximately 100 mA h g −1 , thereby indicating its excellent high power performance. The sample also shows enhanced cycling performance with 88.5%, 79.9% and 90.5% of capacity retention after 100 cycles at 0.5, 5 and 10 C rates, respectively. Besides, 84.5% of initial capacity is retained even after 200 cycles at 10 C. Consequently, the fascinating electrochemical performance may facilitate the coralline-like LMNCO composite to be a promising alternative cathode for LIBs with a high application potential

  15. Preparation of ultrasmall porous carbon nanospheres by reverse microemulsion-hydrothermal method

    Science.gov (United States)

    Wang, Jiasheng; Zhao, Yahong; Wang, Wan-Hui; Bao, Ming

    Porous carbon nanospheres (CNSs) have wide applications. A big challenge in materials science is synthesis of discrete ultrasmall porous carbon nanospheres. Herein, we report a facile reverse microemulsion-hydrothermal method to prepare discrete porous CNSs. The obtained CNSs possess an average diameter of 20nm and pores of 0.7nm and 3.4nm. Our work has provided a convenient method for the controllable synthesis of ultrasmall porous CNSs with potential applications.

  16. Exploration Method Development for hydrothermal plume hunting by XCTD

    Science.gov (United States)

    Kitagawa, Y.; Ikeda, M.; Kadoshima, K.; Koizumi, Y.; Nakano, J.; Asakawa, E.; Sumi, T.

    2017-12-01

    J-MARES (Research and Development Partnership for Next Generation Technology of Marine Resources Survey, JAPAN) has been designing a low-cost and high-efficiency exploration system for seafloor hydrothermal massive sulfide deposits in "Cross-ministerial Strategic Innovation Promotion Program (SIP)" granted by the Cabinet Office, Government of Japan since 2014. We proposed hydrothermal plume hunting by XCTD (eXpendables Conductivity, Temperature and Depth). We applied this method to an area of interest more than 100km x 100km over Okinawa Trough, including some known seafloor massive sulfide deposits. Generally, hydrothermal plume exploration has been by ship mounted with MBES (Multi Beam Echo Sounder) or AUV with sound anomaly observation. However, these methods have to charter the sophisticated ship costly. On the other hand, throw-in type water quality meters (eg. XCTD and XBT) can be low-cost and easily operable. Moreover, that can make a quick look at seawater temperature and conductivity even in rough waters.Firstly, we confirmed XCTD probes position on the seafloor by ROV mounted deep-sea high vision camera. As a result of the test, probes swept downstream about 40 m in horizontal distance from throwing positions with about 1,600m in water depth. Following the previous test results, we had performed to the next test that confirmed detection range of hydrothermal plume at the chimney of North Mound in Izena Cauldron, so we had caught anomaly of seawater temperature and conductivity successfully which could be possibly derived from hydrothermal activities. Although averaged seawater temperature at a depth of 1500 m or more was about 3.95 degrees C, near the chimney was about 4.93 degrees C. The temperature anomalies originated from the hydrothermal plumes could be distributed at most 30m in horizontal distance and became smaller away from the chimney. Moreover, temperature anomaly mass of sea water tended to move upward in depth with distance away from the

  17. Facile Hydrothermal Synthesis of Tellurium Nanostructures for Solar Cells

    Directory of Open Access Journals (Sweden)

    M. Panahi-Kalamuei

    2014-10-01

    Full Text Available Tellurium (Te nanostructures have been successfully synthesized via a simple hydrothermal methodfrom the reaction of a TeCl4 aqueous solution with thioglycolic acid (TGA as a reductant. TGA can be easily oxidized to the corresponding disulfide [SCH2CO2H]2, which in turn can reduce TeCl4 to Te. The obtained Te was characterized by XRD, SEM, EDS, and DRS. The effect of reducing agent on morphology and size of the products were also studied. Additionally, Te thin film was deposited on the FTO-TiO2 by Dr- blading then employed to solar cell application and measured open circuit voltage (Voc, short circuit current (Isc, and fill factor (FF were determined as well. The studies showed that particle morphology and sizes play crucial role on solar cell efficiencies.

  18. Piezoelectric Materials Synthesized by the Hydrothermal Method and Their Applications

    Directory of Open Access Journals (Sweden)

    Takeshi Morita

    2010-12-01

    Full Text Available Synthesis by the hydrothermal method has various advantages, including low reaction temperature, three-dimensional substrate availability, and automatic polarization alignment during the process. In this review, powder synthesis, the fabrication of piezoelectric thin films, and their applications are introduced. A polycrystalline lead zirconate titanate (PZT thin film was applied to a micro ultrasonic motor, and an epitaxial lead titanate (PbTiO3 thin film was estimated as a ferroelectric data storage medium. Ferroelectric and piezoelectric properties were successfully obtained for epitaxial PbTiO3 films. As lead-free piezoelectric powders, KNbO3 and NaNbO3 powders were synthesized by the hydrothermal method and sintered together to form (K,NaNbO3 ceramics, from which reasonable piezoelectric performance was achieved.

  19. Hydrothermal analysis in engineering using control volume finite element method

    CERN Document Server

    Sheikholeslami, Mohsen

    2015-01-01

    Control volume finite element methods (CVFEM) bridge the gap between finite difference and finite element methods, using the advantages of both methods for simulation of multi-physics problems in complex geometries. In Hydrothermal Analysis in Engineering Using Control Volume Finite Element Method, CVFEM is covered in detail and applied to key areas of thermal engineering. Examples, exercises, and extensive references are used to show the use of the technique to model key engineering problems such as heat transfer in nanofluids (to enhance performance and compactness of energy systems),

  20. Investigations on photoelectrochemical performance of boron doped ZnO nanorods synthesized by facile hydrothermal technique

    Science.gov (United States)

    Sharma, Akash; Chakraborty, Mohua; Thangavel, R.

    2018-05-01

    Undoped and 10% Boron (B)-doped Zinc Oxide nanorods (ZnO NRs) on Tin doped Indium Oxide (ITO) coated glass substrates were synthesized using facile sol-gel, spin coating and hydrothermal method. The impact of adding Boron on the structural, optical properties, surface morphology and photoelectrochemical (PEC) performances of the ZnO NRs have been investigated. The XRD pattern confirmed the formation of pure hexagonal phase with space group P63mc (186). The same can also be clearly observed form the FESEM images. The UV-Vis study shows the narrowing in band gap from 3.22 eV to 3.19 eV with incorporation of Boron in ZnO matrix. The B-doped ZnO NRs sample shows an enhanced photocurrent density of 1.31 mA/cm2 at 0.5 V (vs. Ag/AgCl), which is more than 171% enhancement compared to bare ZnO NRs (0.483 mA/cm2) in 0.1 M Na2SO4 aqueous solution. The results clearly indicates that the boron doped ZnO NRs can be used as an efficient photoelectrode material for photoelectrochemical cell.

  1. Facile hydrothermal synthesis of one-dimensional nanostructured α-MnO2 for supercapacitors

    Science.gov (United States)

    Wei, Hongmei; Wang, Jinxing; Yang, Shengwei; Zhang, Yangyang; Li, Tengfei; Zhao, Shuoqing

    2016-09-01

    α-MnO2 recently becomes a promising candidate of electrode materials for high effective supercapacitors in which it possesses of unique structure of 2×2 tunnels that can provide more electrons and ions diffusion paths. In this work, different morphologies MnO2 with α-phase crystalline structure have been prepared via a one-step facile hydrothermal method by adding various reagents. Compositions, microstructures and morphologies of these as-synthesized materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and electrochemical properties of α-MnO2 electrodes were studied by the cyclic voltammetry (CV), galvanostatic charge/discharge and electrochemical impedance spectroscopy (EIS) in 1 M Na2SO4 aqueous solution. The specific capacitance of nanowires were 158 F g-1 while the specific capacitance of nanorods were 106 F g-1 at current density of 4 A g-1, and improved performance of the wire-like electrode material was probably ascribed to the larger specific surface area that can provide relatively more active sites for high capacity. Meanwhile, both the nanowires and nanorods of MnO2 presented fine cycle stability after continuous multiple charge/discharge times.

  2. Multiperiod hydrothermal economic dispatch by an interior point method

    Directory of Open Access Journals (Sweden)

    Kimball L. M.

    2002-01-01

    Full Text Available This paper presents an interior point algorithm to solve the multiperiod hydrothermal economic dispatch (HTED. The multiperiod HTED is a large scale nonlinear programming problem. Various optimization methods have been applied to the multiperiod HTED, but most neglect important network characteristics or require decomposition into thermal and hydro subproblems. The algorithm described here exploits the special bordered block diagonal structure and sparsity of the Newton system for the first order necessary conditions to result in a fast efficient algorithm that can account for all network aspects. Applying this new algorithm challenges a conventional method for the use of available hydro resources known as the peak shaving heuristic.

  3. Controlled Synthesis of Manganese Dioxide Nano structures via a Facile Hydrothermal

    International Nuclear Information System (INIS)

    Pang, R.S.C.; Chin, S.F.; Ye, Ch. Ling

    2012-01-01

    Manganese dioxide nano structures with controllable morphological structures and crystalline phases were synthesized via a facile hydrothermal route at low temperatures without using any templates or surfactants. Both the aging duration and aging temperatures were the main synthesis parameters used to influence and control the rate of morphological and structural evolution of MnO 2 nano structures. MnO 2 nano structures comprise of spherical nano particulate agglomerates and highly amorphous in nature were formed at lower temperature and/or short aging duration. In contrast, MnO 2 nano structures of sea-urchin-like and nano rods-like morphologies and nanocrystalline in nature were prepared at the combined higher aging temperatures and longer aging durations. These nano structures underwent notable phase transformation from d-MnO 2 to a-MnO 2 upon prolonged hydrothermal aging duration and exhibited accelerated rate of phase transformation at higher aging temperature.

  4. Preparation of antimony-doped nanoparticles by hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    JIANG Ming-xi; YANG Tian-zu; GU Ying-ying; DU Zuo-juan; LIU Jian-ling

    2005-01-01

    Antimony-doped tin oxide(ATO) nanoparticles were prepared by the mild hydrothermal method at 200 ℃ using sodium stannate, antimony oxide, sodium hydroxide and sulfuric acid as the starting materials. The doped powders were examined by differential thermal analysis(DTA), X-ray diffractometry(XRD) and transmission electron microscopy(TEM). The doping levels of antimony were determined by volumetric method and iodimetry.The results show that antimony is incorporated into the crystal lattice of tin oxide and the doping levels of antimony in the resulting powders are 2.4%, 4.3 % and 5.1 % (molar fraction). The mean particle size of ATO nanoparticles is in the range of 25 - 30 nm. The effects of antimony doping level on the crystalline size and crystallinity were also discussed.

  5. BCT phase formation in synthesis via microwave assisted hydrothermal method

    International Nuclear Information System (INIS)

    Barra, B.C.; Souza, A.E.; Teixeira, S.R.; Santos, G.T.A.; Lanzi, C.A.C.

    2012-01-01

    In previous work, samples of barium and calcium titanate (Ba1-xCaxTiO3 (BCT x = 0- 1) were prepared using the microwave assisted hydrothermal method in conditions of relatively short time and temperature. To the sample with 75wt% of Ca no BCT phase was formed but the photoluminescent emission was improved. In the present study, these titanates were synthesized by the same method with other concentrations of Ca, Ba1-xCaxTiO3 (x = 0, 0.20, 0.40, 0. 60, 0.80 and 1) to evaluate the limit of BCT phase formation. Results of X-ray diffraction showed that the phase BCT is formed between zero and 50wt%-Ca, in Ba substitution. Above this concentration, was observed only the formation of carbonates, and to x = 1 there was carbonate formation together with CaTiO3. These results were confirmed by micro Raman spectroscopy. (author)

  6. Preparation of thermally stable nanocrystalline hydroxyapatite by hydrothermal method.

    Science.gov (United States)

    Prakash Parthiban, S; Elayaraja, K; Girija, E K; Yokogawa, Y; Kesavamoorthy, R; Palanichamy, M; Asokan, K; Narayana Kalkura, S

    2009-12-01

    Thermally stable hydroxyapatite (HAp) was synthesized by hydrothermal method in the presence of malic acid. X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), differential thermal analysis (DTA), thermogravimetric analysis (TGA) was done on the synthesized powders. These analyses confirmed the sample to be free from impurities and other phases of calcium phosphates, and were of rhombus morphology along with nanosized particles. IR and Raman analyses indicated the adsorption of malic acid on HAp. Thermal stability of the synthesized HAp was confirmed by DTA and TGA. The synthesized powders were thermally stable upto 1,400 degrees C and showed no phase change. The proposed method might be useful for producing thermally stable HAp which is a necessity for high temperature coating applications.

  7. A facile hydrothermal synthesis, characterization and magnetic properties of mesoporous CoFe{sub 2}O{sub 4} nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, M. Penchal, E-mail: reddy@nimte.ac.cn [Center for Advanced Materials, Qatar University, Doha 2713 (Qatar); Mohamed, A.M.A. [Center for Advanced Materials, Qatar University, Doha 2713 (Qatar); Department of Metallurgical and Materials Engineering, Faculty of Petroleum and Mining Engineering, Suez University, Suez 4372 (Egypt); Zhou, X.B.; Du, S.; Huang, Q. [Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), Ningbo 315201, Zhejiang, RP China (China)

    2015-08-15

    Mesoporous CoFe{sub 2}O{sub 4} nanospheres with an average size of 180 nm were fabricated via a facile hydrothermal process using ethylene glycol as solvent and sodium acetate (NaAc) as electrostatic stabilizer. In this method, ethylene glycol plays a vital role in the formation of cobalt nanoospheres as a solvent and reducing agent. The structure and morphology of the prepared materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The nanospheres exhibited ferromagnetic properties with high saturation magnetization value of about 60.19 emu/g at room temperature. The BET surface area of the nanospheres was determined using the nitrogen absorption method. The porous CoFe{sub 2}O{sub 4} nanospheres displayed good magnetic properties, which may provide a very promising candidate for their applications in target drug delivery. - Highlights: • CoFe{sub 2}O{sub 4} nanospheres were prepared by hydrothermal synthesis for the first time. • Average grain size was found to be 180 nm. • Its structural, morphological, magnetic behavior was studied. • TEM observations confirmed the spherical morphology of the mesoporous ferrites.

  8. Facile hydrothermal growth graphene/ZnO nanocomposite for development of enhanced biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Low, Sze Shin [Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Division of Materials, Mechanics and Structures, Center of Nanotechnology and Advanced Materials, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Tan, Michelle T.T., E-mail: Michelle.Tan@nottingham.edu.my [Department of Electrical and Electronic Engineering, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Division of Materials, Mechanics and Structures, Center of Nanotechnology and Advanced Materials, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Loh, Hwei-San [School of Biosciences, Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Biotechnology Research Centre, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Khiew, Poi Sim [Division of Materials, Mechanics and Structures, Center of Nanotechnology and Advanced Materials, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Chiu, Wee Siong [Low Dimensional Materials Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2016-01-15

    Graphene/zinc oxide nanocomposite was synthesised via a facile, green and efficient approach consisted of novel liquid phase exfoliation and solvothermal growth for sensing application. Highly pristine graphene was synthesised through mild sonication treatment of graphite in a mixture of ethanol and water at an optimum ratio. The X-ray diffractometry (XRD) affirmed the hydrothermal growth of pure zinc oxide nanoparticles from zinc nitrate hexahydrate precursor. The as-prepared graphene/zinc oxide (G/ZnO) nanocomposite was characterised comprehensively to evaluate its morphology, crystallinity, composition and purity. All results clearly indicate that zinc oxide particles were homogenously distributed on graphene sheets, without any severe aggregation. The electrochemical performance of graphene/zinc oxide nanocomposite-modified screen-printed carbon electrode (SPCE) was evaluated using cyclic voltammetry (CV) and amperometry analysis. The resulting electrode exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H{sub 2}O{sub 2}) in a linear range of 1–15 mM with a correlation coefficient of 0.9977. The sensitivity of the graphene/zinc oxide nanocomposite-modified hydrogen peroxide sensor was 3.2580 μAmM{sup −1} with a limit of detection of 7.4357 μM. An electrochemical DNA sensor platform was then fabricated for the detection of Avian Influenza H5 gene based on graphene/zinc oxide nanocomposite. The results obtained from amperometry study indicate that the graphene/zinc oxide nanocomposite-enhanced electrochemical DNA biosensor is significantly more sensitive (P < 0.05) and efficient than the conventional agarose gel electrophoresis. - Highlights: • One step, green and facile exfoliation of graphite in ethanol/water mixture. • G/ZnO nanocomposite prepared via simple, green low temperature solvothermal method. • CV and amperometric study of G/ZnO nanocomposite towards H{sub 2}O{sub 2} with R{sup 2} of 0.9977.

  9. Phosphonate-hydroxyapatite hybrid compounds prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Agougui, H.; Aissa, A. [Laboratoire de Physico-Chimie des Materiaux, Faculte des sciences de Monastir, 5019 Monastir (Tunisia); Maggi, S. [CNR-IC Istituto di Cristallografia, via Amendola 122/O, 70126 Bari (Italy); Debbabi, M., E-mail: m.debbabi@yahoo.fr [Laboratoire de Physico-Chimie des Materiaux, Faculte des sciences de Monastir, 5019 Monastir (Tunisia)

    2010-12-15

    Calcium hydroxyapatite (CaHAp) was prepared in the presence of two alkylphosphonates, the tert-butyl phosphonic acid TBPOH and the 2-carboxyletylphosphonic acid 2-CEPA, by hydrothermal method at 120 deg. C for 15 h. The modification of hydroxyapatite by grafting organic moieties is confirmed by IR and NMR MAS ({sup 1}H and {sup 31}P) spectroscopy and chemical analysis. X-ray powder diffraction patterns show that the incorporation of organic moieties induces a significant loss of the material crystallinity and a clear increase of the unit cell lattice parameter a as function of 2-CEPA grafting rate. The specific surface area (SSA) increases with increasing phosphonate amount especially for 2-CEPA. All techniques show the lower reactivity of TBPOH due to the steric effects of tert-butyl, whereas the 2-CEPA with a linear chain and double acidic functions is more reactive and can replace the OH{sup -} groups of the apatitic structure.

  10. Hydroxyapatite-phosphonoformic acid hybrid compounds prepared by hydrothermal method

    Science.gov (United States)

    Turki, Thouraya; Othmani, Masseoud; Bantignies, Jean-Louis; Bouzouita, Khaled

    2014-01-01

    Hydroxyapatites were prepared in the presence of different amounts of phosphonoformic acid (PFA) via the hydrothermal method. The obtained powders were characterized through chemical analysis, XRD, IR, 31P MAS-NMR, TEM, and TG-TDA. The XRD showed that the PFA did not affect the apatite composition. Indeed, only a reduction of the crystallite size was noted. After grafting of PFA, the IR spectroscopy revealed the appearance of new bands belonging to HPO42- and carboxylate groups of the apatite and organic moiety, respectively. Moreover, the 31P MAS-NMR spectra exhibited a peak with a low intensity assigned to the terminal phosphonate group of the organic moiety in addition to that of the apatite. Based on these results, a reaction mechanism involving the surface hydroxyl groups (tbnd Casbnd OH) of the apatite and the carboxyl group of the acid was proposed.

  11. Phosphonate-hydroxyapatite hybrid compounds prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Agougui, H.; Aissa, A.; Maggi, S.; Debbabi, M.

    2010-01-01

    Calcium hydroxyapatite (CaHAp) was prepared in the presence of two alkylphosphonates, the tert-butyl phosphonic acid TBPOH and the 2-carboxyletylphosphonic acid 2-CEPA, by hydrothermal method at 120 deg. C for 15 h. The modification of hydroxyapatite by grafting organic moieties is confirmed by IR and NMR MAS ( 1 H and 31 P) spectroscopy and chemical analysis. X-ray powder diffraction patterns show that the incorporation of organic moieties induces a significant loss of the material crystallinity and a clear increase of the unit cell lattice parameter a as function of 2-CEPA grafting rate. The specific surface area (SSA) increases with increasing phosphonate amount especially for 2-CEPA. All techniques show the lower reactivity of TBPOH due to the steric effects of tert-butyl, whereas the 2-CEPA with a linear chain and double acidic functions is more reactive and can replace the OH - groups of the apatitic structure.

  12. Carbon/Clay nanostructured composite obtained by hydrothermal method

    International Nuclear Information System (INIS)

    Barin, G.B.; Bispo, T.S.; Gimenez, I.F.; Barreto, L.S.; Souza Filho, A.G.

    2010-01-01

    The development of strategies for converting biomass into useful materials, more efficient energy carrier and / or hydrogen storage is shown a key issue for the present and future. Carbon nanostructure can be obtained by severe processing techniques such as arc discharge, chemical deposition and catalyzed pyrolysis of organic compounds. In this study we used hydrothermal methods for obtaining nanostructured composites of carbon / clay. To this end, we used coir dust and special clays. The samples were characterized by infrared spectroscopy, X-ray diffraction and Raman. The presence of the D band at 1350 cm -1 in the Raman spectrum shows the formation of amorphous carbon with particle size of about 8.85 nm. (author)

  13. Synthesis and luminescence properties of (Zn,Cd)S:Ag nanocrystals by hydrothermal method

    International Nuclear Information System (INIS)

    Luo Xixian; Cao Wanghe; Zhou Lixin

    2007-01-01

    ZnS:Ag and (Zn,Cd)S:Ag nanoparticles with particle sizes of about 50 and 150 nm have been prepared by hydrothermal method. The effects of hydrothermal process on the physical and luminescence characteristics are investigated. The photoluminescence intensities of hydrothermal treatment ZnS:Ag samples are 10 times higher than that of non-treated samples after annealing at 800 deg. C

  14. Facile hydrothermal method synthesis of coralline-like Li{sub 1.2}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} hierarchical architectures as superior cathode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xianhua [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), Guangzhou 510006 (China); Huang, Yanling, E-mail: yanling3963@126.com [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), Guangzhou 510006 (China); Ma, Shaomeng; Zou, Xiaoli; Hu, Shejun [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), Guangzhou 510006 (China); Wu, Yuping [Institute of Advanced Materials, Nanjing University of Technology, Nanjing 210009 (China)

    2015-03-15

    Highlights: • A coralline-like Li{sub 1.20}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} cathode was synthesized by hydrothermal method. • Initial discharge capacity of 250.2 mAh g{sup −1} for the cathode was obtained at 0.1 C. • A high reversible specific capacity of 210.2 mAh g{sup −1} after 100 cycles was acquired. • The high capacity retention of 84.5% was obtained even after 200 cycles at 10 C. - Abstract: A coralline-like lithium-rich layered cathode material with homogeneous composition of Li{sub 1.20}Mn{sub 0.54}Ni{sub 0.13}Co{sub 0.13}O{sub 2} has been successfully synthesized via a facile ethanolamine (EA)-mediated hydrothermal method route, with subsequent calcination at 850 °C. An initial specific discharge capacity of 250.2 mAh g{sup −1} and a reversible specific capacity of 210.2 mAh g{sup −1} after 100 cycles at a constant density of 25 mA g{sup −1} (1 C = 250 mA g{sup −1}) are acquired. Even at 10 C, it still delivers a discharge capacity of approximately 100 mA h g{sup −1}, thereby indicating its excellent high power performance. The sample also shows enhanced cycling performance with 88.5%, 79.9% and 90.5% of capacity retention after 100 cycles at 0.5, 5 and 10 C rates, respectively. Besides, 84.5% of initial capacity is retained even after 200 cycles at 10 C. Consequently, the fascinating electrochemical performance may facilitate the coralline-like LMNCO composite to be a promising alternative cathode for LIBs with a high application potential.

  15. Evaluation methods for hospital facilities

    DEFF Research Database (Denmark)

    Fronczek-Munter, Aneta

    2013-01-01

    according to focus areas and proposes which evaluation methods to use in different building phases of healthcare facilities. Hospital evaluations with experts and users are also considered; their subjective view on space, function, technology, usability and aesthetics. Results & solutions: This paper...... presents the different methods for evaluating buildings in use in a new model, the Evaluation Focus Flower, and proposes which evaluation methods are suitable for various aims and building phases, i.e. which is giving best input for the initial briefing process of new hospital facilities with ambition...... of creating buildings with enhanced usability. Additionally various evaluation methods used in hospital cases in Denmark and Norway are presented. Involvement of users is proposed, not just in defining requirements but also in co-creation/design and evaluation of solutions. The theories and preliminary...

  16. Synthesis and characterization of nanosized MnZn ferrites via a modified hydrothermal method

    Science.gov (United States)

    Li, Mingling; Liu, Xiansong; Xu, Taotao; Nie, Yu; Li, Honglin; Zhang, Cong

    2017-10-01

    Nanosized MnZn ferrite particles, with narrow size distribution, regular morphology and high saturation magnetization have been synthesized via a modified hydrothermal method. This modified hydrothermal method involves a chemical co-precipitation of hydroxides under a vacuum condition using potassium hydroxide as precipitating agent, followed by a separate hydrothermal process. The microstructure and magnetic properties of the synthesized nanoparticles were investigated by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometer (VSM). The effects of different synthesis conditions (excess ratio of precipitating agent and hydrothermal reaction time) on the microstructure and magnetic properties of the as-synthesized nanoparticles were discussed. The magnetic measurements indicated that the obtained samples were superparamagnetic in nature at room temperature. Moreover, the MnZn ferrite nanoparticles with excellent magnetic performance could be synthesized at 180 °C for a short reaction time (3 h).

  17. Multicolor Tunable Luminescence Based on Tb3+/Eu3+ Doping through a Facile Hydrothermal Route.

    Science.gov (United States)

    Wang, Chao; Zhou, Ting; Jiang, Jing; Geng, Huiyuan; Ning, Zhanglei; Lai, Xin; Bi, Jian; Gao, Daojiang

    2017-08-09

    Ln 3+ -doped fluoride is a far efficient material for realizing multicolor emission, which plays an important part in full-color displays, biolabeling, and MRI. However, studies on the multicolor tuning properties of Ln 3+ -doped fluoride are mainly concentrated on a complicated process using three or more dopants, and the principle of energy transfer mechanism is still unclear. Herein, multicolor tunable emission is successfully obtained only by codoping with Tb 3+ and Eu 3+ ions in β-NaGdF 4 submicrocrystals via a facile hydrothermal route. Our work reveals that various emission colors can be obtained and tuned from red, orange-red, pink, and blue-green to green under single excitation energy via codoping Tb 3+ and Eu 3+ with rationally changed Eu 3+ /Tb 3+ molar ratio due to the energy transfer between Tb 3+ and Eu 3+ ions in the β-NaGdF 4 host matrix. Meanwhile, the energy transfer mechanism in β-NaGdF 4 : x Eu 3+ /y Tb 3+ (x + y = 5 mol %) submicrocrystals is investigated. Our results evidence the potential of the dopants' distribution density as an effective way for analyzing energy transfer and multicolor-controlled mechanism in other rare earth fluoride luminescence materials. Discussions on the multicolor luminescence under a certain dopant concentration based on single host and wavelength excitation are essential toward the goal of the practical applications in the field of light display systems and optoelectronic devices.

  18. Protein Adsorption and Antibacterial Behavior for Hydroxyapatite Nanocrystals Prepared by Hydrothermal Method

    OpenAIRE

    笠原, 英充; 小形, 信男; 荻原, 隆

    2005-01-01

    Homogeneous hydroxyapatite nanocrystals which have aspect ratio with more than four were synthesized by hydrothermal method. X-ray fluorescence analysis revealed that the Ca/P ratio of hydroxyapatite nanocrystals was maintaining start composition. The protein adsorption properties and bacteria-resistant of hydroxyapatite nanocrystals were investigated. The protein adsorption properties of hydroxyapatite nanocrystals were improvement after the hydrothermal treatment. Bacteria-resistant behavio...

  19. Rare Earth Oxide Fluoride Nanoparticles And Hydrothermal Method For Forming Nanoparticles

    Science.gov (United States)

    Fulton, John L.; Hoffmann, Markus M.

    2003-12-23

    A hydrothermal method for forming nanoparticles of a rare earth element, oxygen and fluorine has been discovered. Nanoparticles comprising a rare earth element, oxygen and fluorine are also described. These nanoparticles can exhibit excellent refractory properties as well as remarkable stability in hydrothermal conditions. The nanoparticles can exhibit excellent properties for numerous applications including fiber reinforcement of ceramic composites, catalyst supports, and corrosion resistant coatings for high-temperature aqueous solutions.

  20. Short run hydrothermal coordination with network constraints using an interior point method

    International Nuclear Information System (INIS)

    Lopez Lezama, Jesus Maria; Gallego Pareja, Luis Alfonso; Mejia Giraldo, Diego

    2008-01-01

    This paper presents a lineal optimization model to solve the hydrothermal coordination problem. The main contribution of this work is the inclusion of the network constraints to the hydrothermal coordination problem and its solution using an interior point method. The proposed model allows working with a system that can be completely hydraulic, thermal or mixed. Results are presented on the IEEE 14 bus test system

  1. Synthesis of Graphene-CdSe Composite by a Simple Hydrothermal Method and Its Photocatalytic Degradation of Organic Dyes

    Institute of Scientific and Technical Information of China (English)

    OH Won-Chun; CHEN Mingliang; CHO Kwangyoun; KIM Cheolkyu; MENG Zeda; ZHULei

    2011-01-01

    A graphene-CdSe composite was synthesized by a facile hydrothermal method,and characterized by X-ray diffiraction,scanning electron microscopy with energy dispersive X-ray analysis,transmission electron microscopy and UV-vis diffuse reflectance spectrophotometry.The graphene-CdSe composite efficiently catalyzed the photodegradation of methylene blue (MB),methyl orange (MO) and rhodamine B (Rh.B) in aqueous solution under UV or visible light irradiation.The graphene-CdSe composite exhibited a higher photocatalytic activity for the MB solution.

  2. Facile hydrothermal growth graphene/ZnO nanocomposite for development of enhanced biosensor.

    Science.gov (United States)

    Low, Sze Shin; Tan, Michelle T T; Loh, Hwei-San; Khiew, Poi Sim; Chiu, Wee Siong

    2016-01-15

    Graphene/zinc oxide nanocomposite was synthesised via a facile, green and efficient approach consisted of novel liquid phase exfoliation and solvothermal growth for sensing application. Highly pristine graphene was synthesised through mild sonication treatment of graphite in a mixture of ethanol and water at an optimum ratio. The X-ray diffractometry (XRD) affirmed the hydrothermal growth of pure zinc oxide nanoparticles from zinc nitrate hexahydrate precursor. The as-prepared graphene/zinc oxide (G/ZnO) nanocomposite was characterised comprehensively to evaluate its morphology, crystallinity, composition and purity. All results clearly indicate that zinc oxide particles were homogenously distributed on graphene sheets, without any severe aggregation. The electrochemical performance of graphene/zinc oxide nanocomposite-modified screen-printed carbon electrode (SPCE) was evaluated using cyclic voltammetry (CV) and amperometry analysis. The resulting electrode exhibited excellent electrocatalytic activity towards the reduction of hydrogen peroxide (H2O2) in a linear range of 1-15 mM with a correlation coefficient of 0.9977. The sensitivity of the graphene/zinc oxide nanocomposite-modified hydrogen peroxide sensor was 3.2580 μAmM(-1) with a limit of detection of 7.4357 μM. An electrochemical DNA sensor platform was then fabricated for the detection of Avian Influenza H5 gene based on graphene/zinc oxide nanocomposite. The results obtained from amperometry study indicate that the graphene/zinc oxide nanocomposite-enhanced electrochemical DNA biosensor is significantly more sensitive (P < 0.05) and efficient than the conventional agarose gel electrophoresis. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Facile Br- assisted hydrothermal synthesis of Bi2MoO6 nanoplates with enhanced visible-light photocatalytic activity

    International Nuclear Information System (INIS)

    Zhang, Peng; Teng, Xiaoxu; Liu, Dongsheng; Fu, Liang; Xie, Hualin; Zhang, Guoqing; Ding, Shimin

    2017-01-01

    Bi 2 MoO 6 nanoplates have been controllably synthesized via a facile hydrothermal process with the assistance of Br - containing surfactant cetyltrimethylammonium bromide (CTAB) or KBr. A remarkable enhancement in the visible-light-driven photocatalytic degradation of Rhodamine B was observed. It was found that reaction temperature and surfactant play crucial roles in the formation and properties of the Bi 2 MoO 6 nanoplates. The best results as photocatalyst were obtained with the sample hydrothermally synthesized at 150 C with the assistance of CTAB. The improved photocatalytic performance could be ascribed to the {001}-oriented nanostructure of the Bi 2 MoO 6 nanoplates. KBr-templated Bi 2 MoO 6 nanoplates also showed better photocatalytic efficiency compared with that of flower-like Bi 2 MoO 6 but inferior to that of CTAB-templated Bi 2 MoO 6 nanoplates. (orig.)

  4. Methods and apparatus for catalytic hydrothermal gasification of biomass

    Science.gov (United States)

    Elliott, Douglas C.; Butner, Robert Scott; Neuenschwander, Gary G.; Zacher, Alan H.; Hart, Todd R.

    2012-08-14

    Continuous processing of wet biomass feedstock by catalytic hydrothermal gasification must address catalyst fouling and poisoning. One solution can involve heating the wet biomass with a heating unit to a temperature sufficient for organic constituents in the feedstock to decompose, for precipitates of inorganic wastes to form, for preheating the wet feedstock in preparation for subsequent separation of sulfur contaminants, or combinations thereof. Treatment further includes separating the precipitates out of the wet feedstock, removing sulfur contaminants, or both using a solids separation unit and a sulfur separation unit, respectively. Having removed much of the inorganic wastes and the sulfur that can cause poisoning and fouling, the wet biomass feedstock can be exposed to the heterogeneous catalyst for gasification.

  5. Rapid synthesis of single-phase bismuth ferrite by microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Wenqian [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Chen, Zhi, E-mail: zchen0@gmail.com [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Gao, Tong; Zhou, Dantong; Leng, Xiaonan; Niu, Feng [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Zhu, Yuxiang [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Tianjin Key Laboratory of Marine Resources and Chemistry, Tianjin University of Science and Technology, Tianjin (China); Qin, Laishun, E-mail: qinlaishun@yeah.net [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China); Wang, Jiangying; Huang, Yuexiang [College of Materials Science and Engineering, China Jiliang University, 258 Xueyuan Street, Xiasha Higher Education District, Hangzhou 310018, Zhejiang Province (China)

    2016-06-01

    This paper describes on the fast synthesis of bismuth ferrite by the simple microwave-assisted hydrothermal method. The phase transformation and the preferred growth facets during the synthetic process have been investigated by X-ray diffraction. Bismuth ferrite can be quickly prepared by microwave hydrothermal method by simply controlling the reaction time, which is further confirmed by Fourier Transform infrared spectroscopy and magnetic measurement. - Graphical abstract: Single-phase BiFeO{sub 3} could be realized at a shortest reaction time of 65 min. The reaction time has strong influences on the phase transformation and the preferred growth facets. - Highlights: • Rapid synthesis (65 min) of BiFeO{sub 3} by microwave-assisted hydrothermal method. • Reaction time has influence on the purity and preferred growth facets. • FTIR and magnetic measurement further confirm the pure phase.

  6. Rapid synthesis of single-phase bismuth ferrite by microwave-assisted hydrothermal method

    International Nuclear Information System (INIS)

    Cao, Wenqian; Chen, Zhi; Gao, Tong; Zhou, Dantong; Leng, Xiaonan; Niu, Feng; Zhu, Yuxiang; Qin, Laishun; Wang, Jiangying; Huang, Yuexiang

    2016-01-01

    This paper describes on the fast synthesis of bismuth ferrite by the simple microwave-assisted hydrothermal method. The phase transformation and the preferred growth facets during the synthetic process have been investigated by X-ray diffraction. Bismuth ferrite can be quickly prepared by microwave hydrothermal method by simply controlling the reaction time, which is further confirmed by Fourier Transform infrared spectroscopy and magnetic measurement. - Graphical abstract: Single-phase BiFeO_3 could be realized at a shortest reaction time of 65 min. The reaction time has strong influences on the phase transformation and the preferred growth facets. - Highlights: • Rapid synthesis (65 min) of BiFeO_3 by microwave-assisted hydrothermal method. • Reaction time has influence on the purity and preferred growth facets. • FTIR and magnetic measurement further confirm the pure phase.

  7. Facile one-step hydrothermal synthesis toward strongly coupled TiO2/graphene quantum dots photocatalysts for efficient hydrogen evolution

    International Nuclear Information System (INIS)

    Min, Shixiong; Hou, Jianhua; Lei, Yonggang; Ma, Xiaohua; Lu, Gongxuan

    2017-01-01

    Highlights: • TiO 2 /GQDs composites were prepared by a facile one-step hydrothermal method. • GQDs were strongly coupled onto the surface of TiO 2 nanoparticles by this method. • The TiO 2 /GQDs showed enhanced light absorption and charge separation efficiency. • The TiO 2 /GQDs exhibited higher photocatalytic H 2 evolution activity than pure TiO 2 . • GQDs play synergistic roles by acting as both photosensitizer and electron acceptor. - Abstract: The coupling of semiconductor photocatalysts with graphene quantum dots (GQDs) has been proven to be an effective strategy to enhance the photocatalytic and photoelectrical conversion performances of the resulted composites; however, the preparation of semiconductor/GQDs composites usually involves several time-inefficient and tedious post-treatment steps. Herein, we present a facile one-step hydrothermal route for the preparation of GQDs coupled TiO 2 (TiO 2 /GQDs) photocatalysts using 1,3,6-trinitropyrene (TNP) as the sole precursor of GQDs. During the hydrothermal process, TNP molecules undergo an intramolecular fusion to form GQDs, which simultaneously decorate on the surface of TiO 2 nanoparticles, leading to a strong surface interaction between the two components. The effective coupling of GQDs on TiO 2 can effectively extend the light absorption of the TiO 2 to visible region and enhance the charge separation efficiency of TiO 2 /GQDs composites as a result of GQDs acting as a photosensitizer and an excellent electron acceptor. These key advances make the TiO 2 /GQDs photocatalyst highly active towards the H 2 evolution reaction, resulting in 7 and 3 times higher H 2 evolution rate and photocurrent response at optimal GQDs content than TiO 2 alone, respectively. This study provides a new methodology for the development of high-performance GQDs modified semiconductor photocatalysts for energy conversion applications.

  8. Fabrication of Mineralized Collagen from Bovine Waste Materials by Hydrothermal Method as Promised Biomaterials

    DEFF Research Database (Denmark)

    Sheikh, Faheem A.; Kanjwal, Muzafar Ahmed; Macossay, Javier

    2011-01-01

    In the present study, we aimed to produce mineralized-collagen by hydrothermal process. A simple method not depending on additional foreign chemicals has been employed to isolate the mineralized-collagen fibers from bovine waste. The process of extraction involves the use of hydrothermal method...... mineral content in the individual fibers. The X-ray diffraction showed the crystalline feature of the obtained nano-compounds. The thermo gravimetric analysis was used to differentiate between the collagen and mineral parts of obtained product. Overall, the results generously indicated production of well...

  9. Analytical methods used at model facility

    International Nuclear Information System (INIS)

    Wing, N.S.

    1984-01-01

    A description of analytical methods used at the model LEU Fuel Fabrication Facility is presented. The methods include gravimetric uranium analysis, isotopic analysis, fluorimetric analysis, and emission spectroscopy

  10. Synthesis of mesoporous cerium-zirconium mixed oxides by hydrothermal templating method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mesoporous cerium-zirconium mixed oxides were prepared by hydrothermal method using cetyl trimethyl ammonium bromide (CTAB) as template.The effects of amount of template,pH value of solution and hydrothermal temperature on mesostructure of samples were systematically investigated.The final products were characterized by XRD,TEM,FT-IR,and BET.The results indicate that all the cerium-zirconium mixed oxides present a meso-structure.At molar ratio of n(CTAB)/n((Ce)+(Zr))=0.15,pH value of 9,and hydrothermal temperature of 120 ℃,the samples obtained possess a specific surface area of 207.9 m2/g with pore diameter of 3.70 nm and pore volume of 0.19 cm3/g.

  11. Nucleation control and inhibition of BaTiO3 films using hydrothermal-electrochemical method

    International Nuclear Information System (INIS)

    Escobar, Ivan; Silva, Carmen; Silva, Eric; Vargas, Tomas; Fuenzalida, Victor

    1999-01-01

    The microstructure of BaTiO 3 films on titanium by the hydrothermal-electrochemical method was investigated using a three electrode high pressure electrochemical cell in a 0.2 M Ba(OH) 2 electrolyte at 150 0 C. The spontaneous initial linked to pure hydrothermal BaTiO 3 formation can be inhibited by cathodically protecting titanium electrode since its immersion in the electrolyte. The application of initial nucleation pulses of varying the cathodic potentials affected the grain size of the deposit. It is suggested that the formation of a titanium oxide layers is a necessary step previous to the nucleation of BaTiO 3

  12. Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method.

    Science.gov (United States)

    Ohta, Kanako; Isobe, Gaku; Bornmann, Peter; Hemsel, Tobias; Morita, Takeshi

    2013-04-01

    The hydrothermal method utilizes a solution-based chemical reaction to synthesize piezoelectric thin films and powders. This method has a number of advantages, such as low-temperature synthesis, and high purity and high quality of the product. In order to promote hydrothermal reactions, we developed an ultrasonic assisted hydrothermal method and confirmed that it produces dense and thick lead-zirconate-titanate (PZT) films. In the hydrothermal method, a crystal growth process follows the nucleation process. In this study, we verified that ultrasonic irradiation is effective for the nucleation process, and there is an optimum irradiation period to obtain thicker PZT films. With this optimization, a 9.2-μm-thick PZT polycrystalline film was obtained in a single deposition process. For this film, ultrasonic irradiation was carried out from the beginning of the reaction for 18 h, followed by a 6 h deposition without ultrasonic irradiation. These results indicate that the ultrasonic irradiation mainly promotes the nucleation process. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Construction method for plant facility

    International Nuclear Information System (INIS)

    Ito, Arata; Hirono, Hideharu; Kyoda, Shigeru; Hanawa, Minoru; Sato, Hitoshi

    1998-01-01

    A caisson structure is disposed on a construction site for facilities of nuclear power plants. A digging work is performed below the caisson structure and, simultaneous with the digging work, a construction of a base, construction of plant facilities including a building and installation of plant facility are performed on the caisson structure. Then, the caisson structure is sank together with the structures on a base rock in association with the progress of the digging work and secured on the base rock. When securing them on the base rock, a groove is formed to the base rock along tuyere of the caisson structure so that the tuyere and a ceiling portion of the caisson structure are in direct contact with the base rock. Since the construction for the containing building conducted on the caisson structure is performed simultaneous with the digging work conducted below the caisson structure, the term required for the construction of the plant facilities can greatly reduced. (N.H.)

  14. Facile hydrothermal preparation of recyclable S-doped graphene sponge for Cu2+ adsorption

    International Nuclear Information System (INIS)

    Zhao, Lianqin; Yu, Baowei; Xue, Fumin; Xie, Jingru; Zhang, Xiaoliang; Wu, Ruihan; Wang, Ruijue; Hu, Zhiyan; Yang, Sheng-Tao; Luo, Jianbin

    2015-01-01

    Graphical abstract: S-doped graphene sponge was prepared via hydrothermal treatment, where S-doped graphene sponge had an adsorption capacity of 228 mg/g for Cu 2+ . - Highlights: • S-doped graphene sponge was prepared by hydrothermal treatment for heavy metal adsorption. • S-doped graphene sponge had a huge adsorption capacity for Cu 2+ , which was 40 times higher than that of active carbon. • S-doped graphene sponge could be easily regenerated by washing with acidic thiourea. - Abstract: Graphene sponge (GS) has been widely employed for water purification, but adsorption capacity loss frequently occurs during the formation of spongy structure. In this study, we reported the hydrothermal preparation of S-doped GS for the removal of Cu 2+ with a huge adsorption capacity of 228 mg/g, 40 times higher than that of active carbon. The adsorption isotherm could be well fitted into the Freundlich model with a K F value of 36.309 (L/mg) 1/n . The equilibrium adsorption could be fully achieved in the first 5 min. In the thermodynamics study, the negative ΔG indicated that the adsorption was spontaneous and physisorption in nature. The positive ΔH implied that the adsorption was endothermic. The changes of both pH and ionic strength had no apparent influence on the adsorption. S-doped GS could be easily regenerated by washing with acidic thiourea. Moreover, S-doped GS could be used for the adsorption of other heavy metal ions, too. The implication to the applications of S-doped GS in water treatment is discussed

  15. Facile Hydrothermal Preparation of ZNO/CO3O4 Heterogeneous Nanostructures and its Photovoltaic Effect

    Science.gov (United States)

    Wei, Fanan; Jiang, Minlin; Liu, Lianqing

    2015-07-01

    Photovoltaic technology offers great potential in the replacement of fossil fuel resources, but still suffers from high device fabrication cost. Herein, we attempted to provide a solution to these issues with heterogeneous nanostructures. Firstly, Zinc oxide (ZnO)/cobalt oxide (Co3O4) heterojunction nanowires are prepared through facile fabrication methods. By assembling Co(OH)2 nanoplates on ZnO nanowire arrays, the ZnO/Co3O4 heterogeneous nanostructures are uniformly synthesized on ITO coated glass and wafer. Current (I)-voltage (V) measurement through conductive atomic force microscope shows excellent photovoltaic effect. And, the heterojunction nanostructures shows unprecedented high open circuit voltage. Therefore, the potential application of the heterogeneous nanostructures in solar cells is demonstrated.

  16. Facile one-step hydrothermal synthesis and luminescence properties of Eu{sup 3+}-doped NaGd(WO{sub 4}){sub 2} nanophosphors

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Zehan; Cai, Peiqing; Chen, Cuili; Pu, Xipeng; Kim, Sun Il, E-mail: sikim@pknu.ac.kr; Jin Seo, Hyo, E-mail: hjseo@pknu.ac.kr

    2017-06-01

    Eu{sup 3+}-doped NaGd(WO{sub 4}){sub 2} nanophosphors were synthesized via a facile one-step hydrothermal method without any surfactants or a further heat treatment. X-ray powder diffraction (XRD), scanning electron microscope (SEM), fourier transform infrared spectroscopy (FT-IR), the photoluminescence (PL) excitation and emission spectra, and decay curves were used to characterize NaGd(WO{sub 4}){sub 2}:Eu{sup 3+} phosphors. The results show that the Eu{sup 3+}-concentration has little influence on the structure and morphology of the as-synthesized samples. However, pH value plays a vital role on the structure and morphology of NaGd(WO{sub 4}){sub 2}. The well-crystallized sheet-like NaGd(WO{sub 4}){sub 2} phosphors can be obtained only at pH = 5–7. On the basis of the time-dependent synthesis, a possible growth mechanism of sheet-like architectures is proposed. The luminescence properties of NaGd{sub 1-x}Eu{sub x}(WO{sub 4}){sub 2} (0 ≤ x ≤ 1) are investigated. It is found that the charge transfer band of Eu{sup 3+} shifts to lower energy and broadens with increasing the Eu{sup 3+}-concentration. - Highlights: • NaGd(WO{sub 4}){sub 2}:Eu{sup 3+} nanosheets were synthesized by facile one-step hydrothermal method. • Luminescence properties of NaGd(WO{sub 4}){sub 2}:Eu{sup 3+} phosphor were firstly reported. • The CT band of Eu{sup 3+} depends strongly on Eu{sup 3+}-concentrations.

  17. Hydrothermal Method Using DMF as a Reducing Agent for the Fabrication of PdAg Nanochain Catalysts towards Ethanol Electrooxidation

    Directory of Open Access Journals (Sweden)

    Yue Feng

    2016-07-01

    Full Text Available In this article, we developed a facile one-step hydrothermal method using dimethyl formamide (DMF as a reducing agent for the fabrication of PdAg catalyst. The scanning electron microscope (SEM and transmission electron microscopy (TEM images have shown that the as-synthesized PdAg catalyst had a nanochain structure. The energy-dispersive X-ray analyzer (EDX spectrum presented the actual molar ratio of Pd and Ag in the PdAg alloy. Traditional electrochemical measurements, such as cyclic voltammetry (CV, chronoamperometry (CA and electrochemical impedance spectrometry (EIS, were performed using a CHI 760D electrochemical analyzer to characterize the electrochemical properties of the as-synthesized catalyst. The results have shown that the PdAg catalyst with a nanochain structure displays higher catalytic activity and stability than pure Pd and commercial Pd/C catalysts.

  18. Size effect in barium titanate powders synthesized by different hydrothermal methods

    International Nuclear Information System (INIS)

    Sun Weian

    2006-01-01

    The size effect in barium titanate (BaTiO 3 ) was investigated both experimentally and theoretically. Tetragonal BaTiO 3 powders with average sizes from 80 to 420 nm were directly prepared by different hydrothermal methods. The tetragonality of the hydrothermal BaTiO 3 decreased with decreasing particle size, which exhibited a dependence on the synthesis method. A phenomenological model for the size effect was proposed to interpret the experimental observations. The influence of the defects, mainly the lattice hydroxyl, on the size effect was investigated to understand the correlation between the size effect and synthesis condition. The permittivities of BaTiO 3 powder at different particle sizes were calculated, which predicted a maximum permittivity of over 16 000 around the room-temperature critical size of ∼70 nm. The prediction was in good accordance with the experimental data reported recently

  19. Rapid synthesis of nitrogen doped titania with mixed crystal lattice via microwave-assisted hydrothermal method

    International Nuclear Information System (INIS)

    Zhang Peilin; Liu Bin; Yin Shu; Wang Yuhua; Petrykin, Valery; Kakihana, Masato; Sato, Tsugio

    2009-01-01

    A microwave-assisted hydrothermal method was employed to synthesize nitrogen doped titania nanoparticles. Due to the high heating efficiency of microwave, rapid synthesis could be achieved in comparison with the conventional oven. Mixed crystal lattice was found existing in the obtained product, and the phase transformation behaviour under calcination was studied by XRD measurement together with Raman spectroscopy in details. The obtained nitrogen doped titania showed high specific surface area, about 300 m 2 g -1 . Photocatalytic activity in destructing NO x gas by the prepared sample exceeded that of commercial titania (P 25) or nitrogen doped titania synthesized by conventional hydrothermal method, under both visible-light and ultraviolet-light irradiation.

  20. Photocatalytic properties of hierarchical ZnO flowers synthesized by a sucrose-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Lv Wei [Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025 (China); Wei Bo [Center for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology, Harbin 150080 (China); Xu Lingling, E-mail: xulingling_hit@163.com [Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025 (China) and Center for Condensed Matter Science and Technology, Department of Physics, Harbin Institute of Technology, Harbin 150080 (China); Zhao Yan, E-mail: zhaoyan516@126.com [Department of Physics, Northeast Forestry University, Harbin 150040 (China); Gao Hong; Liu Jia [Key Laboratory of Photonic and Electric Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer Hierarchical ZnO flowers were synthesized via a sucrose-assisted urea hydrothermal method. Black-Right-Pointing-Pointer The sucrose added ZnO flowers showed improved activity mainly due to the improved crystallinity. Black-Right-Pointing-Pointer The effect of sucrose content was studied and optimized. - Abstract: In this work, hierarchical ZnO flowers were synthesized via a sucrose-assisted urea hydrothermal method. The thermogravimetric analysis/differential thermal analysis (TGA-DTA) and Fourier transform infrared spectra (FTIR) showed that sucrose acted as a complexing agent in the synthesis process and assisted combustion during annealing. Photocatalytic activity was evaluated using the degradation of organic dye methyl orange. The sucrose added ZnO flowers showed improved activity, which was mainly attributed to the better crystallinity as confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The effect of sucrose amount on photocatalytic activity was also studied.

  1. development of a hydrothermal method to synthesize spherical znse

    African Journals Online (AJOL)

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    nanoparticles have a zinc blend structure and in a spherical form with ... optoelectronic devices such as blue-green laser diodes and turnable mid-IR ... Solvothermal methods have also been developed for the synthesis of ZnSe and CdSe. The.

  2. A facile hydrothermal strategy for synthesis of SnO2 nanorods-graphene nanocomposites for high performance photocatalysis.

    Science.gov (United States)

    Chen, Lu-Ya; Zhang, Wei-De; Xu, Bin; Yu, Yu-Xiang

    2012-09-01

    In this study, we report a facilely hydrothermal process for synthesizing SnO2 nanorods-graphene (SnO2 nanorods-GR) composite using graphite oxide and SnCl4 as raw materials. The SnO2 nanorods-GR composite was characterized by X-ray diffraction, electron microscopy, Xray photoelectron spectroscopy, and thermogravimetric analysis. Compared to commercial TiO2 nanoparticles P25 and neat SnO2 nanorods, the SnO2 nanorods-GR composite exhibits higher photocatalytic activity under UV light irradiation. The mechanism of its high photocatalytic activity is mainly ascribed to the synergy effect between SnO2 and graphene, in which graphene acts as an adsorbent and electron acceptor due to its large structure of pi-pi conjugation from sp2 hybrid carbon atoms. The results demonstrated in this study provide a promising way to enhance the photocatalytic activity by compounding semiconductive nanocrystals with graphene.

  3. Facile one-step hydrothermal synthesis toward strongly coupled TiO{sub 2}/graphene quantum dots photocatalysts for efficient hydrogen evolution

    Energy Technology Data Exchange (ETDEWEB)

    Min, Shixiong, E-mail: sxmin@nun.edu.cn [School of Chemistry and Chemical Engineering, Beifang University of Nationalities, Yinchuan, 750021, Ningxia Province (China); Hou, Jianhua; Lei, Yonggang; Ma, Xiaohua [School of Chemistry and Chemical Engineering, Beifang University of Nationalities, Yinchuan, 750021, Ningxia Province (China); Lu, Gongxuan [State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

    2017-02-28

    Highlights: • TiO{sub 2}/GQDs composites were prepared by a facile one-step hydrothermal method. • GQDs were strongly coupled onto the surface of TiO{sub 2} nanoparticles by this method. • The TiO{sub 2}/GQDs showed enhanced light absorption and charge separation efficiency. • The TiO{sub 2}/GQDs exhibited higher photocatalytic H{sub 2} evolution activity than pure TiO{sub 2}. • GQDs play synergistic roles by acting as both photosensitizer and electron acceptor. - Abstract: The coupling of semiconductor photocatalysts with graphene quantum dots (GQDs) has been proven to be an effective strategy to enhance the photocatalytic and photoelectrical conversion performances of the resulted composites; however, the preparation of semiconductor/GQDs composites usually involves several time-inefficient and tedious post-treatment steps. Herein, we present a facile one-step hydrothermal route for the preparation of GQDs coupled TiO{sub 2} (TiO{sub 2}/GQDs) photocatalysts using 1,3,6-trinitropyrene (TNP) as the sole precursor of GQDs. During the hydrothermal process, TNP molecules undergo an intramolecular fusion to form GQDs, which simultaneously decorate on the surface of TiO{sub 2} nanoparticles, leading to a strong surface interaction between the two components. The effective coupling of GQDs on TiO{sub 2} can effectively extend the light absorption of the TiO{sub 2} to visible region and enhance the charge separation efficiency of TiO{sub 2}/GQDs composites as a result of GQDs acting as a photosensitizer and an excellent electron acceptor. These key advances make the TiO{sub 2}/GQDs photocatalyst highly active towards the H{sub 2} evolution reaction, resulting in 7 and 3 times higher H{sub 2} evolution rate and photocurrent response at optimal GQDs content than TiO{sub 2} alone, respectively. This study provides a new methodology for the development of high-performance GQDs modified semiconductor photocatalysts for energy conversion applications.

  4. Microwave assisted facile hydrothermal synthesis and characterization of zinc oxide flower grown on graphene oxide sheets for enhanced photodegradation of dyes

    International Nuclear Information System (INIS)

    Kashinath, L.; Namratha, K.; Byrappa, K.

    2015-01-01

    Graphical abstract: - Highlights: • Synthesis of hybrid ZnO–GO nanocomposite via microwave assisted facile hydrothermal method. • The in situ flower like ZnO nano particles are densely decorated and anchored on the surfaces of graphene oxide sheets. • They exhibited high adsorption measurement, increase in surface area and meso/micro porous in nature. • The structure and morphology plays a vital role in enhancing the photo response activities of degradation of dyes. - Abstract: Microwave assisted hydrothermal process of synthesis of ZnO–GO nanocomposite by using ZnCl 2 and NaOH as precursors is being reported first time. In this investigation, a novel route to study on synthesis, interaction, kinetics and mechanism of hybrid zinc oxide–graphene oxide (ZnO–GO) nanocomposite using microwave assisted facile hydrothermal method has been reported. The results shows that the ZnO–GO nanocomposite exhibits an enhancement and acts as stable photo-response degradation performance of Brilliant Yellow under the UV light radiation better than pure GO and ZnO nanoparticles. The microwave exposure played a vital role in the synthesis process, it facilitates with well define crystalline structure, porosity and fine morphology of ZnO/GO nanocomposite. Different molar concentrations of ZnO precursors doped to GO sheets were been synthesized, characterized and their photodegradation performances were investigated. The optical studies by UV–vis and Photo Luminescence shows an increase in band gap of nanocomposite, which added an advantage in photodegradation performance. The in situ flower like ZnO nano particles are were densely decorated and anchored on the surfaces of graphene oxide sheets which aids in the enhancement of the surface area, adsorption, mass transfer of dyes and evolution of oxygen species. The nanocomposite having high surface area and micro/mesoporous in nature. This structure and morphology supports significantly in increasing photo catalytic

  5. Fabrication of mesoporous silica nanoparticles by sol gel method followed various hydrothermal temperature

    Science.gov (United States)

    Purwaningsih, Hariyati; Pratiwi, Vania Mitha; Purwana, Siti Annisa Bani; Nurdiansyah, Haniffudin; Rahmawati, Yenny; Susanti, Diah

    2018-04-01

    Rice husk is an agricultural waste that is potentially used as natural silica resources. Natural silica claimed to be safe in handling, cheap and can be generate from cheap resource. In this study mesoporous silica was synthesized using sodium silicate extracted from rice husk ash. This research's aim are to study the optimization of silica extraction from rice husk, characterizing mesoporous silica from sol-gel method and surfactant templating from rice husk and the effect of hydrothermal temperature on mesoporous silica nanoparticle (MSNp) formation. In this research, rice husk was extracted with sol-gel method and was followed by hydrothermal treatment; several of hydrothermal temperatures were 85°C, 100°C, 115°C, 130°C and 145° for 24 hours. X-ray diffraction analysis was identified of α-SiO2 phase and NaCl compound impurities. Scherer's analysis method for crystallite size have resulted 6.27-40.3 nm. FTIR results of silica from extraction and MSNp indicated Si-O-Si bonds on the sample. SEM result showed the morphology of the sample that has spherical shape and smooth surface. TEM result showed particle size ranged between 69,69-84,42 nm. BET showed that the pore size classified as mesoporous with pore diameter size is 19,29 nm.

  6. Dye-Sensitized Solar Cells with Anatase TiO2 Nanorods Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Ming-Jer Jeng

    2013-01-01

    Full Text Available The hydrothermal method provides an effective reaction environment for the synthesis of nanocrystalline materials with high purity and well-controlled crystallinity. In this work, we started with various sizes of commercial TiO2 powders and used the hydrothermal method to prepare TiO2 thin films. We found that the synthesized TiO2 nanorods were thin and long when smaller TiO2 particles were used, while larger TiO2 particles produced thicker and shorter nanorods. We also found that TiO2 films prepared by TiO2 nanorods exhibited larger surface roughness than those prepared by the commercial TiO2 particles. It was found that a pure anatase phase of TiO2 nanorods can be obtained from the hydrothermal method. The dye-sensitized solar cells fabricated with TiO2 nanorods exhibited a higher solar efficiency than those fabricated with commercial TiO2 nanoparticles directly. Further, triple-layer structures of TiO2 thin films with different particle sizes were investigated to improve the solar efficiency.

  7. Multiobjective CVaR Optimization Model and Solving Method for Hydrothermal System Considering Uncertain Load Demand

    Directory of Open Access Journals (Sweden)

    Zhongfu Tan

    2015-01-01

    Full Text Available In order to solve the influence of load uncertainty on hydrothermal power system operation and achieve the optimal objectives of system power generation consumption, pollutant emissions, and first-stage hydropower station storage capacity, this paper introduced CVaR method and built a multiobjective optimization model and its solving method. In the optimization model, load demand’s actual values and deviation values are regarded as random variables, scheduling objective is redefined to meet confidence level requirement and system operation constraints and loss function constraints are taken into consideration. To solve the proposed model, this paper linearized nonlinear constraints, applied fuzzy satisfaction, fuzzy entropy, and weighted multiobjective function theories to build a fuzzy entropy multiobjective CVaR model. The model is a mixed integer linear programming problem. Then, six thermal power plants and three cascade hydropower stations are taken as the hydrothermal system for numerical simulation. The results verified that multiobjective CVaR method is applicable to solve hydrothermal scheduling problems. It can better reflect risk level of the scheduling result. The fuzzy entropy satisfaction degree solving algorithm can simplify solving difficulty and get the optimum operation scheduling scheme.

  8. The Characterization of Lithium Titanate Microspheres Synthesized by a Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2013-01-01

    Full Text Available Lithium titanate microspheres were synthesized by a hydrothermal method. The structure and morphology of samples were characterized by X-ray diffraction, infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy, respectively. The specific surface area and average pore diameter of samples were studied by N2 adsorption-desorption isotherms. The results indicated that amorphous phase changed to lithium titanium oxide hydrate, accompanying mesopores formed between agglomerated primary particles in hydrothermal reaction. After sintering, mesoporous Li4Ti5O12 microspheres assembled by nanosized particle were obtained and had a diameter of about 400–700 nm. Then, a possible formation process analogous to the Kirkendall effect was proposed. Moreover, the effect of sintering temperature on the electrochemical properties of Li4Ti5O12 microspheres was investigated.

  9. Short-term hydro-thermal scheduling using particle swarm optimization method

    International Nuclear Information System (INIS)

    Yu, Binghui; Yuan, Xiaohui; Wang, Jinwen

    2007-01-01

    The approaches based on different particle swarm optimization (PSO) techniques are applied to solve the short-term hydro-thermal scheduling problem. In the proposed methods, many constraints of the hydro-thermal system, such as power balance, water balance, reservoir volume limits and the operation limits of hydro and thermal plants, are considered. The feasibility of the proposed algorithm is demonstrated through an example system, and the results are compared with the results of a genetic algorithm and evolutionary programming approaches. The experimental results show that all the PSO algorithms have the ability to achieve nearly global solutions, but a local version of PSO with inertia weight appears to be the best amongst all the PSOs in terms of high quality solution

  10. Facile hydrothermal synthesis of mn doped ZnO nanopencils for development of amperometric glucose biosensors

    Science.gov (United States)

    Shukla, Mayoorika; Pramila; Agrawal, Jitesh; Dixit, Tejendra; Palani, I. A.; Singh, Vipul

    2018-05-01

    Mn doped ZnO nanopencils were synthesized via low temperature hydrothermal process for fabrication of enzymatic electrochemical glucose biosensor. The KMnO4 was found to play a dual role in modifying morphology and inducing Mn doping. Interestingly, two different types of morphologies viz nanorods and nanopencils along with Mn doping in the later were obtained. Incorporation of Mn has shown a tremendous effect on the morphological variations, repression of defects and electrochemical charge transfer at electrode electrolyte interface. The possible reason behind obtained morphological changes has been proposed which in turn were responsible for the improvement in the different figure of merits of as fabricated enzymatic electrochemical biosensor. There has been a 17 fold enhancement in the sensitivity of the as fabricated glucose biosensor from ZnO nanorods to Mn doped ZnO nanopencils which can be attributed to morphological variation and Mn doping.

  11. Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite

    Science.gov (United States)

    Chang, Betty Yea Sze; Huang, Nay Ming; An’amt, Mohd Nor; Marlinda, Abdul Rahman; Norazriena, Yusoff; Muhamad, Muhamad Rasat; Harrison, Ian; Lim, Hong Ngee; Chia, Chin Hua

    2012-01-01

    A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm). Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II) ions in potassium chloride electrolyte. PMID:22848166

  12. Preparation high photocatalytic activity of CdS/halloysite nanotubes (HNTs) nanocomposites with hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Xing Weinan [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Ni Liang, E-mail: xingweinan3@126.com [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Huo Pengwei; Lu Ziyang; Liu Xinlin; Luo Yingying; Yan Yongsheng [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer CdS/halloysite nanotubes (HNTs) were synthesized by hydrothermal method. Black-Right-Pointing-Pointer The CdS/HNTs had better photocatalytic activity for degradation of tetracycline. Black-Right-Pointing-Pointer The presence of halloysite nanotubes both improved its photocatalytic activity and stability. - Abstract: A novel nanocatalyst CdS/halloysite nanotubes (HNTs) was synthesized by hydrothermal method with direct growth of CdS nanoparticles on the surface of HNTs. The as-prepared photocatalysts had been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), Fourier transform infrared (FT-IR) and the thermo gravimetric analysis (TGA). The photocatalytic activity of the sample was evaluated by the degradation of tetracycline (TC) under visible light irradiation. Benefit from the excellent properties of CdS and HNTs, the photocatalyst exhibited good photocatalytic activity and stability. In order to find out the optimum synthesis condition to obtain the best photocatalytic activity, a series of experiments were performed with different CdS loading capacity, different sources of sulfide and different hydrothermal temperatures, etc. The best photodegradation rate could reach 93% in 60 min under visible light irradiation. Therefore, the combination of CdS nanoparticles with HNTs endowed this material with a potential use in environmental treatments in industries.

  13. Preparation high photocatalytic activity of CdS/halloysite nanotubes (HNTs) nanocomposites with hydrothermal method

    International Nuclear Information System (INIS)

    Xing Weinan; Ni Liang; Huo Pengwei; Lu Ziyang; Liu Xinlin; Luo Yingying; Yan Yongsheng

    2012-01-01

    Highlights: ► CdS/halloysite nanotubes (HNTs) were synthesized by hydrothermal method. ► The CdS/HNTs had better photocatalytic activity for degradation of tetracycline. ► The presence of halloysite nanotubes both improved its photocatalytic activity and stability. - Abstract: A novel nanocatalyst CdS/halloysite nanotubes (HNTs) was synthesized by hydrothermal method with direct growth of CdS nanoparticles on the surface of HNTs. The as-prepared photocatalysts had been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV–vis diffuse reflectance spectra (UV–vis DRS), Fourier transform infrared (FT-IR) and the thermo gravimetric analysis (TGA). The photocatalytic activity of the sample was evaluated by the degradation of tetracycline (TC) under visible light irradiation. Benefit from the excellent properties of CdS and HNTs, the photocatalyst exhibited good photocatalytic activity and stability. In order to find out the optimum synthesis condition to obtain the best photocatalytic activity, a series of experiments were performed with different CdS loading capacity, different sources of sulfide and different hydrothermal temperatures, etc. The best photodegradation rate could reach 93% in 60 min under visible light irradiation. Therefore, the combination of CdS nanoparticles with HNTs endowed this material with a potential use in environmental treatments in industries.

  14. Crystallization Mechanism and Phase Transition Properties of W-doped VO2 Synthesized by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    LI Yao

    2017-11-01

    Full Text Available VO2 sol was firstly prepared using vanadyl sulfate as a vanadium source by precipitation-peptization method. Then tungsten(W doping vanadium dioxide(W-VO2 was prepared by hydrothermal crystallization of prepared sol with the presence of ammonium metatungstate. The morphologies, crystal structure of the as-prepared samples and phase transition properties were studied by X-ray diffraction(XRD, field emission scanning electron microscope(FESEMand differential scanning calorimetry(DSC analysis. The results indicate that rod-like W-VO2(B crystal with length of 1-2μm and radius of 100-200nm is firstly formed during hydrothermal treatment for 4-48h at 280℃, then the rod-like crystal dissolves gradually and sheet-like or snowflake-like crystal is formed with the phase transition from W-VO2(B to W-VO2(M and eventually, the W-VO2(M crystals can further grow up while the W-VO2(B gradually dissolves; the phase transition temperature of VO2 decreases with the increase in W doping content, and the phase transition temperature of W-VO2(M reduces to about 28℃ when the nominal dopant concentration is 6.0%(atom fraction.The "nucleation-growth-transformation-ripening" mechanism is proposed as the formation mechanism based on the hydrothermal crystallization and morphological evolution process of W-VO2(M.

  15. Synthesis, structural and optical properties of pure and rare-earth ion doped TiO{sub 2} nanowire arrays by a facile hydrothermal technique

    Energy Technology Data Exchange (ETDEWEB)

    Bandi, Vengala Rao; Raghavan, Chinnambedu Murugesan; Grandhe, Bhaskar kumar; Kim, Sang Su [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Jang, Kiwan, E-mail: kwjang@changwon.ac.kr [Department of Physics, Changwon National University, Changwon 641-773 (Korea, Republic of); Shin, Dong-Soo [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Yi, Soung-Soo [Department of Photonics, Silla University, Busan 617-736 (Korea, Republic of); Jeong, Jung-Hyun [Department of Physics, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2013-11-29

    Single crystalline pure and rare-earth metal ions (Eu{sup 3+} and Ce{sup 3+}) doped TiO{sub 2} nanowire arrays were prepared on conductive fluorine doped indium tin oxide substrates by a facile hydrothermal method. Initially the conditions and parameters were optimized to prepare the high quality TiO{sub 2} nanowire arrays in the absence of organic additives. The average diameter and length of the TiO{sub 2} nanowire were found to be ∼ 30–50 nm and ∼ 0.5–1.5 μm, respectively. The formations of rutile phase structure in all the samples were confirmed by x-ray diffractometric analysis while the transmission electron microscopy confirms the single crystallinity and the maximum orientation of growth direction along [001] for the as-grown TiO{sub 2} nanowire. The optical properties of all the samples were analyzed using photoluminescence spectroscopy. The photocatalytic properties of the pure and doped TiO{sub 2} were investigated for the decomposition of organic toludine blue-O dye under ultraviolet irradiation. The result demonstrates that the Ce{sup 3+}: TiO{sub 2} decomposed almost 90% of the organic dye within 80 min. - Highlights: • Rare-earth (RE) doped TiO{sub 2} nanowire arrays were prepared by hydrothermal method • RE doping enhanced the growth rate of TiO{sub 2} nanowire arrays • The catalysts used to check their photocatalytic activity by toludine blue-O dye • RE doped TiO2 act as unprecedented photocatalyst for organic dye decomposition.

  16. Preparation of meta-stable phases of barium titanate by Sol-hydrothermal method

    Directory of Open Access Journals (Sweden)

    Mahalakshmi Selvaraj

    2015-11-01

    Full Text Available Two low-cost chemical methods of sol–gel and the hydrothermal process have been strategically combined to fabricate barium titanate (BaTiO3 nanopowders. This method was tested for various synthesis temperatures (100 °C to 250 °C employing barium dichloride (BaCl2 and titanium tetrachloride (TiCl4 as precursors and sodium hydroxide (NaOH as mineralizer for synthesis of BaTiO3 nanopowders. The as-prepared BaTiO3 powders were investigated for structural characteristics using x-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The overall analysis indicates that the hydrothermal conditions create a gentle environment to promote the formation of crystalline phase directly from amorphous phase at the very low processing temperatures investigated. XRD analysis showed phase transitions from cubic - tetragonal - orthorhombic - rhombohedral with increasing synthesis temperature and calculated grain sizes were 34 – 38 nm (using the Scherrer formula. SEM and TEM analysis verified that the BaTiO3 nanopowders synthesized by this method were spherical in shape and about 114 - 170 nm in size. The particle distribution in both SEM and TEM shows that as the reaction temperature increases from 100 °C to 250 °C, the particles agglomerate. Selective area electron diffraction (SAED shows that the particles are crystalline in nature. The study shows that choosing suitable precursor and optimizing pressure and temperature; different meta-stable (ferroelectric phases of undoped BaTiO3 nanopowders can be stabilized by the sol-hydrothermal method.

  17. Synthesis and characterization of Zn3Ta2O8 nanomaterials by hydrothermal method

    International Nuclear Information System (INIS)

    Bîrdeanu, M.; Bîrdeanu, A.-V.; Gruia, A.S.; Fagadar-Cosma, E.; Avram, C.N.

    2013-01-01

    Graphical abstract: The results of an experimental program that was focused on obtaining the Zn 3 Ta 2 O 8 nanocrystalline synthesized by hydrothermal method using tantalum (V) oxide and zinc nitrate, the results of the nanomaterial’s structure characterization and the optical spectral properties of such nanomaterials that were thoroughly investigated. Also, the experimental results are compared with ab initio calculations of electronic properties of Zn 3 Ta 2 O 8 . Highlights: •Zn 3 Ta 2 O 8 nanomaterials were synthesized by hydrothermal method and characterized. •The obtained nanomaterials has excellent phosphor, optical and morphological properties. •The material can be used in designing high performance optoelectronical devices. -- Abstract: Zn 3 Ta 2 O 8 has been synthesized by hydrothermal method using tantalum (V) oxide and zinc nitrate. The crystal structure and microstructure, phase composition and the absorption of Zn 3 Ta 2 O 8 nanomaterials were characterized by X-ray diffraction, FT/IR measurements, UV–VIS measurements, PL measurements, SEM and AFM techniques and BET analysis. XRD results show the single phase of Zn 3 Ta 2 O 8 and the average particle size that is 52 nm. This narrow nanometer size was also confirmed by AFM measurements. BET analysis revealed that the nanomaterials are mesoporous. The PL spectra show the blue luminescence of Ta 2 Zn 3 O 8 . Besides, in the present work we report ab initio calculations regarding electronic properties of Zn 3 Ta 2 O 8 ; the theoretical results are compared with the experimental ones

  18. Facile hydrothermal synthesis of alpha manganese sesquioxide (α-Mn2O3) nanodumb-bells: Structural, magnetic, optical and photocatalytic properties

    International Nuclear Information System (INIS)

    Gnanam, S.; Rajendran, V.

    2013-01-01

    Highlights: ► α-Mn 2 O 3 nanoparticles sizes of 35–42 nm have been prepared by hydrothermal process. ► Shapes of α-Mn 2 O 3 : Dumb-bell, Cauliflower, spherical with rod, spherical with wires. ► The strong UV emission can be attributed to high purity and perfect crystallinity. ► Photocatalytic activity of α–Mn 2 O 3 was studied by degradation of Remazol red B dye. - Abstract: Nanometer scale cubic bixbyite α-Mn 2 O 3 has been synthesized by a facile hydrothermal method, at a temperature of 450 °C in the presence of various surfactants. The X-ray diffraction (XRD) analysis shows that the average crystallite size of the sample is ∼35–42 nm. The shapes of the α-Mn 2 O 3 nanoparticles include: Dumb-bell-like (anionic surfactant), Cauliflower-like (nonionic surfactant), spherical with rods (cationic surfactant) and spherical with wires (surface modifier). The shapes of α-Mn 2 O 3 nanoparticles depend on the type of surfactant used in the synthesis. The magnetic property of the anionic surfactant assisted sample was primarily studied, using the vibrating sample magnetometer (VSM). The optical absorption spectra confirmed the effectiveness of the selected capping agents, as the anionic capped α-Mn 2 O 3 colloids absorbed at shorter wavelength than the other agents, indicating a much smaller crystallite size. The property of strong UV emissions may be attributed to the high purity and perfect crystallinity of the as-prepared α-Mn 2 O 3 . The surfactants-assisted catalyst was tested for its photocatalytic activity towards the photodegradation of the harmful organic dye Remazol Red B, using a multilamp photo reactor. Possible formation mechanisms have also been proposed for the as-synthesized anionic surfactant assisted samples.

  19. Optical characterization of infrared emitting Nd{sup 3+} doped hydroxyapatite nanoparticles prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Gayathri, K. [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249 (United States); Kumar, G.A., E-mail: ajith@gakumar.net [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249 (United States); Department of Atomic and Molecular Spectroscopy, Manipal University, Manipal 576104 (India); Northwest Vista College, 3535 N Ellison Dr, San Antonio, TX 78251 (United States); Manrique, Solange Ivette Rivera [Instituto Politécnico Nacional (IPN), Av. Luis Enrique Erro S/N, Unidad Profesional Adolfo López Mateos, Zacatenco, Delegación Gustavo A. Madero, C.P. 07738, Ciudad de México 2009-2010 (Mexico); Santhosh, C. [Department of Atomic and Molecular Spectroscopy, Manipal University, Manipal 576104 (India); Sardar, Dhiraj K. [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249 (United States)

    2017-05-15

    Trivalent Nd doped hydroxyapatite (HAp) nanoparticles were prepared by a hydrothermal method using calcium nitrate and diammonium phosphate as precursors. Well crystallized nanoparticles of size less than 200 nm with hexagonal plate and rod morphologies were obtained at a reaction temperature of 180 °C. Under 808 nm excitation the nanoparticles exhibit strong near infrared emission at 1064 nm. All the emission spectral properties such as emission intensity and fluorescence decay time are found to decrease with Nd{sup 3+} concentration. In Hap 0.5% Nd shows the highest decay time of 159 μs and highest emission at 1064 nm emission.

  20. Synthesis of tungsten oxide nanoparticles using a hydrothermal method at ambient pressure

    DEFF Research Database (Denmark)

    Ahmadi, Majid; Younesi, Reza; Guinel, Maxime J-F

    2014-01-01

    ) nanoparticles were synthesized using a simple and inexpensive low temperature and low pressure hydrothermal (HT) method. The precursor solution used for the HT process was prepared by adding hydrochloric acid to diluted sodium tungstate solutions (Na2WO4 center dot 2H(2)O) at temperatures below 5 degrees C...... and then dissolved using oxalic acid. This HT process yielded tungstite (WO3 center dot H2O) nanoparticles with the orthorhombic structure. A heat treatment at temperatures at or above 300 degrees C resulted in a phase transformation to monoclinic WO3, while preserving the nanoparticles morphology. The production...

  1. Optical characterization of infrared emitting Nd3+ doped hydroxyapatite nanoparticles prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Gayathri, K.; Kumar, G.A.; Manrique, Solange Ivette Rivera; Santhosh, C.; Sardar, Dhiraj K.

    2017-01-01

    Trivalent Nd doped hydroxyapatite (HAp) nanoparticles were prepared by a hydrothermal method using calcium nitrate and diammonium phosphate as precursors. Well crystallized nanoparticles of size less than 200 nm with hexagonal plate and rod morphologies were obtained at a reaction temperature of 180 °C. Under 808 nm excitation the nanoparticles exhibit strong near infrared emission at 1064 nm. All the emission spectral properties such as emission intensity and fluorescence decay time are found to decrease with Nd 3+ concentration. In Hap 0.5% Nd shows the highest decay time of 159 μs and highest emission at 1064 nm emission.

  2. Anticorrosive magnesium hydroxide coating on AZ31 magnesium alloy by hydrothermal method

    International Nuclear Information System (INIS)

    Zhu Yanying; Wu Guangming; Xing Guangjian; Li Donglin; Zhao Qing; Zhang Yunhong

    2009-01-01

    Magnesium alloys are potential biodegradable biomaterials in orthopedic surgery. However, the rapid degradation rate has limited their application in biomedical field. A great deal of studies have been done to improve the resistance of magnesium alloys. In this article, An anticorrosive magnesium hydroxide coating with a thickness of approximately 100μm was formed on an AZ31 magnesium alloy by hydrothermal method. The morphology of the coatings were observed by an optical microscope and SEM. And the samples were soaked in hank's solution (37 deg. C) to investigate the corrosion resistance. Magnesium alloy AZ31 with magnesium hydroxide coatings present superior corrosion resistance than untreated samples.

  3. Defects in ZnO nanorods prepared by a hydrothermal method.

    Science.gov (United States)

    Tam, K H; Cheung, C K; Leung, Y H; Djurisić, A B; Ling, C C; Beling, C D; Fung, S; Kwok, W M; Chan, W K; Phillips, D L; Ding, L; Ge, W K

    2006-10-26

    ZnO nanorod arrays were fabricated using a hydrothermal method. The nanorods were studied by scanning electron microscopy, photoluminescence (PL), time-resolved PL, X-ray photoelectron spectroscopy, and positron annihilation spectroscopy before and after annealing in different environments and at different temperatures. Annealing atmosphere and temperature had significant effects on the PL spectrum, while in all cases the positron diffusion length and PL decay times were increased. We found that, while the defect emission can be significantly reduced by annealing at 200 degrees C, the rods still have large defect concentrations as confirmed by their low positron diffusion length and short PL decay time constants.

  4. Fabrication of indium sulfide nanofibers via a hydrothermal method assisted by AAO template

    International Nuclear Information System (INIS)

    Zhu Xiaoyi; Ma Junfeng; Wang Yonggang; Tao Jiantao; Zhou Jun; Zhao Zhongqiang; Xie Lijin; Tian Hua

    2006-01-01

    β-In 2 S 3 nanofibers were successfully synthesized via a hydrothermal method with AAO membrane as a template at 150 deg. C for 15 h. XRD patterns indicated the perfect crystallization of β-In 2 S 3 . SEM images showed that the β-In 2 S 3 nanofibers grew up from the channel ends of the AAO template. TEM images confirmed that the nanofibers had a high aspect ratio of ca. 40-50 and diameters of about 10 nm. The room temperature photoluminescence (PL) spectrum of the β-In 2 S 3 nanofibers indicated its potential applications in light-emission devices

  5. Multiple objective optimization of hydro-thermal systems using Ritz's method

    Directory of Open Access Journals (Sweden)

    L. Bayón Arnáu

    2000-01-01

    Full Text Available This paper examines the applicability of the Ritz method to multi-objective optimization of hydro-thermal systems. The algorithm proposed is aimed to minimize an objective functional that incorporates the cost of energy losses, the conventional fuel cost and the production of atmospheric emissions such as NOx and SO2 caused by the operation of fossil-fueled thermal generation. The formulation includes a general layout of hydro-plants that may form multi-chains of reservoir network.

  6. Preparation of the Lentinus edodes-based porous biomass carbon by hydrothermal method for capacitive desalination

    Science.gov (United States)

    Yan, Junbin; Zhang, Hexuan; Xie, Zhengzheng; Liu, Jianyun

    2017-08-01

    Biomass carbon materials were prepared by hydrothermal method using Lentinus edodes, followed by activation by ZnCl2 at high carbonization temperature. SEM and contact angle test show that ZnCl2 has a significant effect on the surface morphology and properties of porous carbon materials. Using the porous carbon as electrodes of the capacitor, the specific capacitance of the porous carbon material was found to be 247.6 F/g. The desalination amount of porous carbon material in capacitor cell was 12.9 mg/g, being the 1.9 times of that of the commercial activated carbon.

  7. Refining waste hardmetals into tungsten oxide nanosheets via facile method

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhifei; Zheng, Guangwei; Wang, Jinshu, E-mail: wangjsh@bjut.edu.cn; Li, Hongyi, E-mail: lhy06@bjut.edu.cn; Wu, Junshu; Du, Yucheng [Beijing University of Technology, Key Laboratory of Advanced Functional Materials, School of Materials Science and Engineering (China)

    2016-04-15

    A new hydrothermal system has been designed to recycle waste WC–Co hardmetal with low cobalt (Co) content (3 %). In the solution system, nitric acid was designed to dissolve Co, H{sub 2}O{sub 2} served as oxidant to accelerate the oxidation of the WC–Co hardmetals, and fluorine (F{sup −}) was designed to dissolve and recrystallize generated tungsten oxides, which were found to possess a layered structure using scanning electron microscopy and transmission electron microscopy. The obtained tungsten oxides were identified as WO{sub 3}·0.33H{sub 2}O by X-ray diffraction and their specific surface area was measured as 89.2 m{sup 2} g{sup −1} via N{sub 2} adsorption–desorption techniques. The present layered structure tungsten oxides exhibited a promising capability for removing lead ion (Pb{sup 2+}) and organic species, such as methyl blue. The adsorption model was found to be in agreement with Langmuir isotherm model. Given the facile synthesis procedure and promising properties of final products, this new approach should have great potential for refining some other waste hardmetals or tungsten products.Graphical AbstractA new hydrothermal system was designed to recycle waste hardmetal with low cobalt content. Through this method, waste hardmetal was refined into WO{sub 3}·0.33H{sub 2}O nanosheets which shows excellent adsorption capacities toward methylene blue and lead ion (Pb{sup 2+}).

  8. Synthesis of potassium sodium niobate nanostructures by hydrothermal combining with the sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xianghe; Wang, Wen, E-mail: wangwen@hit.edu.cn; Ke, Hua; Rao, Jiancun; Zhou, Yu

    2016-10-15

    Graphical abstract: We prepared novel metastable perovskite K{sub 0.52}Na{sub 0.48}NbO{sub 3} microstructures with a morphotropic phase boundary (MPB) between rhombohedral and tetragonal via hydrothermal method with SDS surfactant-assist. - Highlights: • KNbO{sub 3}-type orthorhombic K{sub 1−x}Na{sub x}NbO{sub 3} nanowires were prepared by hydrothermal method. • Metastable K{sub 0.52}Na{sub 0.48}NbO{sub 3} microfingers have a morphotropic phase boundary. • Sodium dodecyl sulfate could improve the crystallinity of K{sub 0.52}Na{sub 0.48}NbO{sub 3} powders. • The Curie temperature of rhombohedral-tetragonal KNN was 555 °C. - Abstract: In this paper the K{sub 1−x}Na{sub x}NbO{sub 3}(KNN) nanostructures were synthesized by hydrothermal method using KNN gel powders as precursors. KNbO{sub 3}-type orthorhombic KNN nanowires and perovskite KNN microfingers with a morphotropic phase boundary (MPB) between rhombohedral and tetragonal characterized by X-ray diffraction and Raman spectroscopy were obtained at 190 °C and 220 °C, respectively. KNbO{sub 3}-type orthorhombic KNN nanowires had rectangular shape and the growth direction of these nanowires was [0 0 1]. The rhombohedral-tetragonal KNN microfingers were metastable, and changed the rhombohedral-tetragonal phase into the orthorhombic phase via thermal treatment at 600 °C then cooled down to room temperature. Sodium dodecyl sulfate (SDS) as surfactant was added to the hydrothermal reaction. It was found that SDS could improve the crystallinity of the rhombohedral-tetragonal K{sub 0.52}Na{sub 0.48}NbO{sub 3} and reduce the impurity effectively. The tetragonal-cubic phase transition temperature (Tc) of the rhombohedral-tetragonal powders appeared at 555 °C.

  9. Investigation of the Optimal Parameters in Hydrothermal Method for the Synthesis of ZnO Nanorods

    Directory of Open Access Journals (Sweden)

    Ying-Chung Chen

    2014-01-01

    Full Text Available We investigated a two-step method to deposit the ZnO-based nanostructure films, including nanorods and nanoflowers. In the first step, sputtering method was used to deposit the ZnO films on SiO2/Si substrates as the seed layer. In the second step, Zn(NO32–6H2O and C6H12N4 were used as precursors and hydrothermal process was used as the method to synthesize the ZnO films. After that, the ZnO films were measured by an X-ray diffraction pattern and a FESEM to analyze their crystallization and morphology. We had found that the ZnO films had three different morphologies synthesized on ZnO/SiO2/Si substrates, including irregular-plate structure films, nanorod films, and beautiful chrysanthemum-like clusters (nanoflower films. We would prove that the face direction of ZnO/SiO2/Si substrates in the hydrothermal bottle and deposition time were two important factors to influence the synthesized results of the ZnO films.

  10. Decomposition of Taiwan local black monazite by hydrothermal and soda fusion methods

    International Nuclear Information System (INIS)

    Miao, Y.W.; Horng, J.S.

    1988-01-01

    Along the south-west coast of Taiwan is about 550,000 metric tons of heavy sand deposit containing about 10% black monazite. The institute has developed a separation process to recover the individual rare earths and the developed process has been commercialized by a local private company. The decomposition of the local black monazite by sodium hydroxide through hydrothermal and fusion methods has been investigated. In the hydrothermal process 45 wt. % of aqueous alkali solution was used in an autoclave. In the fusion process, caustic soda (98% NaOH) was employed in an open cylindrical reactor. The same product of hydrous rare earth oxides were obtained and then dissolved by hydrochloric acid and the pH adjusted in order to separate the thorium from the rare earths. After filtration, the filtrate contained rare earth chloride and the cake contained mainly the silica and thorium hydroxide. Both methods give a yield of 90% with respect to the rare earths recovery. A detailed description of operation and comparison of the two methods is given

  11. Photoluminescence properties of PZT 52/48 synthesized by microwave hydrothermal method using PVA with template

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, G.F., E-mail: guilmina@hotmail.com [Instituto de Quimica, Universidade Estadual Paulista, Departamento de Bioquimica e Tecnologia Quimica, Rua Francisco Degni s/n, Quitandinha, 14800-900 Araraquara, SP (Brazil); Gasparotto, G. [Instituto de Quimica, Universidade Estadual Paulista, Departamento de Bioquimica e Tecnologia Quimica, Rua Francisco Degni s/n, Quitandinha, 14800-900 Araraquara, SP (Brazil); Paris, E.C. [Empresa Brasileira de Pesquisa Agropecuaria, Embrapa Instrumentacao, Rua XV de novembro, 1452, Centro, 13.569-970 Sao Carlos, SP (Brazil); Zaghete, M.A.; Longo, E.; Varela, J.A. [Instituto de Quimica, Universidade Estadual Paulista, Departamento de Bioquimica e Tecnologia Quimica, Rua Francisco Degni s/n, Quitandinha, 14800-900 Araraquara, SP (Brazil)

    2012-01-15

    Lead Titanate Zirconate (PZT) perovskite powders were synthesized by microwave hydrothermal method (M-H) at 180 {sup o}C for different time periods (2, 4, 8 and 12 h) with the presence of aqueous polyvinyl alcohol (PVA) solution 0.36 g L{sup -1}. The X-Ray diffraction (XRD), SE-FEG as well as the measurements of photoluminescence (PL) emission were used for monitoring the formation of a perovskite phase with random polycrystalline distortion in the structure. Emission spectra with fixed excitation wavelength of 350 nm showed higher value for the powder obtained after undergoing 8 h of treatment. A theoretical model derived from previous calculations allows us to discuss the origin of photoluminescence emission in the powders, which can be further related to the local disorder in the network of both ZrO{sub 6} and TiO{sub 6} octahedral, and dodecahedral PbO{sub 12}. The new morphology initially observed from the PZT perovskite crystal growth bearing the shape of fine plates is found to be directly related to photoluminescence emission with energy lower than that present in the PZT with cube-like morphology that emits in 560 nm. - Highlights: > This work details the efficiency of microwave hydrothermal synthesis in obtaining PZT powders. > PVA is used as a crystallization agent of PZT particles. > PZT particles presented photoluminescent (PL) behavior. > There aren't previous reports of photoluminescent PZT obtained by microwave hydrothermal synthesis. > Photoluminescence is one more interesting property for technological applications this material.

  12. Synthesis of ZnO nanoparticles using a hydrothermal method and a study its optical activity.

    Science.gov (United States)

    Bharti, Dattatraya B; Bharati, A V

    2017-05-01

    ZnO nanoparticles (NPs) with a granular morphology were synthesized using a hydrothermal method. Structural analysis revealed that ZnO NPs had a single crystal wurtzite hexagonal structure. Solvent polarity was responsible for varying and controlling their size and morphology. The process was very trouble free and scalable. In addition, it could be used for fundamental studies on tunable morphology formation. This hydrothermal method showed different morphology with different co-surfactants such as a floral-like or wire-like belt sheet structures etc. Based on their surface morphology, the same material had different applications as a catalyst in various organic reactions and also could be used as a photocatalyst and fuel cell, solar cell or in semiconductors etc. X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible spectroscopy and photoluminescence of the resulting product was performed to study its purity, morphology and size, plus its optical properties via measurement of band gap energy and light absorbance. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Hydrazine-hydrothermal method to synthesize three-dimensional chalcogenide framework for photocatalytic hydrogen generation

    International Nuclear Information System (INIS)

    Liu Yi; Kanhere, Pushkar D.; Wong, Chui Ling; Tian Yuefeng; Feng Yuhua; Boey, Freddy; Wu, Tom; Chen Hongyu; White, Tim J.; Chen Zhong; Zhang Qichun

    2010-01-01

    A novel chalcogenide, [Mn 2 Sb 2 S 5 (N 2 H 4 ) 3 ] (1), has been synthesized by the hydrazine-hydrothermal method. X-ray crystallography study reveals that the new compound 1 crystallizes in space group P1-bar (no. 2) of the triclinic system. The structure features an open neutral three-dimensional framework, where two-dimensional mesh-like inorganic layers are bridged by intra- and inter-layer hydrazine ligands. Both two Mn1 and Mn2 sites adopt distorted octahedral coordination. While two Sb1 and Sb2 sites exhibit two different coordination geometries, the Sb1 site is coordinated with three S atoms to generate a SbS 3 trigonal-pyramidal geometry, and the Sb2 site adopts a SbS 4 trigonal bipyramidal coordination geometry. It has an optical band gap of about ∼2.09 eV, which was deduced from the diffuse reflectance spectrum, and displays photocatalytic behaviors under visible light irradiation. Magnetic susceptibility measurements show compound 1 obeys the Curie-Weiss law in the range of 50-300 K. -- Graphical abstract: A novel chalcogenide, [Mn 2 Sb 2 S 5 (N 2 H 4 ) 3 ] (1), synthesized by hydrazine-hydrothermal method, has a band gap of about ∼2.09 eV and displays photocatalytic behaviors under visible light irradiation. Display Omitted

  14. Multiple objective optimization of hydro-thermal systems using Ritz's method

    Directory of Open Access Journals (Sweden)

    Arnáu L. Bayón

    1999-01-01

    Full Text Available This paper examines the applicability of the Ritz method to multi-objective optimization of hydro-thermal systems. The algorithm proposed is aimed to minimize an objective functional that incorporates the cost of energy losses, the conventional fuel cost and the production of atmospheric emissions such as NO x and SO 2 caused by the operation of fossil-fueled thermal generation. The formulation includes a general layout of hydro-plants that may form multi-chains of reservoir network. Time-delays are included and the electric network is considered by using the active power balance equation. The volume of water discharge for each hydro-plant is a given constant amount from the optimization interval. The generic minimization algorithm, which is not difficult to construct on the basis of the Ritz method, has certain advantages in comparison with the conventional methods.

  15. Preparation high photocatalytic activity of CdS/halloysite nanotubes (HNTs) nanocomposites with hydrothermal method

    Science.gov (United States)

    Xing, Weinan; Ni, Liang; Huo, Pengwei; Lu, Ziyang; Liu, Xinlin; Luo, Yingying; Yan, Yongsheng

    2012-10-01

    A novel nanocatalyst CdS/halloysite nanotubes (HNTs) was synthesized by hydrothermal method with direct growth of CdS nanoparticles on the surface of HNTs. The as-prepared photocatalysts had been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), Fourier transform infrared (FT-IR) and the thermo gravimetric analysis (TGA). The photocatalytic activity of the sample was evaluated by the degradation of tetracycline (TC) under visible light irradiation. Benefit from the excellent properties of CdS and HNTs, the photocatalyst exhibited good photocatalytic activity and stability. In order to find out the optimum synthesis condition to obtain the best photocatalytic activity, a series of experiments were performed with different CdS loading capacity, different sources of sulfide and different hydrothermal temperatures, etc. The best photodegradation rate could reach 93% in 60 min under visible light irradiation. Therefore, the combination of CdS nanoparticles with HNTs endowed this material with a potential use in environmental treatments in industries.

  16. Influence of fluorine substitution on the morphology and structure of hydroxyapatite nanocrystals prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Joseph Nathanael, A.; Mangalaraj, D.; Hong, S.I.; Masuda, Y.; Rhee, Y.H.; Kim, H.W.

    2013-01-01

    Hydroxyapatite (HAp) nanocrystals with different levels of fluorine substitution (P/F = 0, 6, 4 and 2) on the OH sites were produced via hydrothermal method. The fluorine substitution was found to alter the morphology of crystals appreciably. The aspect ratio and the crystallinity of HAp crystals increased with increasing fluorine substitution. The presence of broad ring and hallow ring patterns in electron diffraction suggests the low-crystalline nature of HAp crystals. With increasing fluorine substitution, the diffraction patterns exhibited discrete rings and numerous diffraction spots, implying the increased crystallinity. Raman spectra from the HAp nanoparticles also support the less-crystalline nature of the pristine HAp and the enhanced crystallization by fluorine substitution. In HAp crystals processed with no fluorine substitution, surface energy and planar Ca 2+ density are less sensitive to the crystallographic orientation because of its low-crystalline nature, favoring equi-axed or slightly elongated particles. The addition of fluorine apparently increased the crystallinity, enhancing the orientation dependent growth and accordingly the aspect ratio. Osteoblast proliferation was observed to be enhanced by fluorine substitution in HAp. In vitro biological data support that the excellent osteoblastic cell viability and functional activity of the fluoridated apatite. -- Highlights: ► Fluorapatite nanorods were produced hydrothermally with different fluorine content. ► Fluorine substitution was found to alter the morphology of crystals appreciably. ► It enhances the crystallinity, orientation dependent growth and hence aspect ratio. ► In vitro cellular analysis shows excellent cell viability of the fluorapatite.

  17. Ion beam analysis of zeolites type Li-ABW synthesized by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, E.; De Lucio, O. G.; Solis, C.; Zavala, E. P.; Cruz, J. [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Alfaro, S.; Rodriguez, C.; Valenzuela, M. A. [IPN, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, Laboratorio de Catalisis y Materiales, Zacantenco, 07738 Mexico D. F. (Mexico); Rocha, M. F. [IPN, Escuela Superior de Ingenieria Mecanica y Electrica, Av. Instituto Politecnico Nacional s/n, Col. Lindavista, 07738 Mexico D. F. (Mexico); Murillo, G.; Policroniades, R. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2010-02-15

    This work reports a method to synthesize and characterize Li-ABW zeolites by a hydrothermal method. These materials are good candidates for CO{sub 2} capture because of the high reactivity between the Li{sup +} with CO{sub 2} to form Li{sub 2}CO{sub 3}. We performed and elemental profile concentration using ion beam analysis. The elastic backscattered proton energy spectra from the Al, Si, O and Li nuclei, in combination with the {alpha} particles from the {sup 7}Li ({rho}, {alpha}){sup 4}He nuclear reaction energy spectra, were employed for this task. X-ray diffraction was also applied to determine the crystalline structure. (Author)

  18. Structural phase transformations in KYF4:Er3+ nanoparticles synthesized by hydrothermal method for upconversion applications

    Science.gov (United States)

    Yamini, S.; Priya, P. Sakthi; Gunaseelan, M.; Senthilselvan, J.

    2017-05-01

    KYF4:10%Er3+ upconversion nanoparticles was synthesized by hydrothermal method with potassium hydroxides (KOH) as precursor. Prepared samples were calcined at 600 °C using double crucible method. XRD patterns of as prepared KYF4 and KYF4:Er3+ samples confirm the tetragonal structure, which is well matched with the standard data. Surface morphology is recorded for 600 °C calcined samples using High resolution scanning electron microscopy (HRSEM) shows spheroidal shape with particle sizes of ˜80 nm. From UV-Visible and EDX spectroscopy presence of Er3+ in KYF4:10%Er3+ is confirmed. The prepared KYF4:10%Er3+ can be used to improve efficiency of solar cells, display devices and fiber optical telecommunication applications.

  19. Synthesis and characterization of WO3 nanostructures prepared by an aged-hydrothermal method

    International Nuclear Information System (INIS)

    Huirache-Acuna, R.; Paraguay-Delgado, F.; Albiter, M.A.; Lara-Romero, J.; Martinez-Sanchez, R.

    2009-01-01

    Nanostructures of tungsten trioxide (WO 3 ) have been successfully synthesized by using an aged route at low temperature (60 deg. C) followed by a hydrothermal method at 200 deg. C for 48 h under well controlled conditions. The material was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). Specific Surface Area (S BET ) were measured by using the BET method. The lengths of the WO 3 nanostructures obtained are between 30 and 200 nm and their diameters are from 20 to 70 nm. The growth direction of the tungsten oxide nanostructures was determined along [010] axis with an inter-planar distance of 0.38 nm.

  20. Facile hydrothermal synthesis of Fe3O4@cellulose aerogel nanocomposite and its application in Fenton-like degradation of Rhodamine B.

    Science.gov (United States)

    Jiao, Yue; Wan, Caichao; Bao, Wenhui; Gao, He; Liang, Daxin; Li, Jian

    2018-06-01

    A magnetic cellulose aerogel-supported Fe 3 O 4 nanoparticles composite was designed as a highly efficient and eco-friendly catalyst for Fenton-like degradation of Rhodamine B (RhB). The composite (coded as Fe 3 O 4 @CA) was formed by embedding well-dispersed Fe 3 O 4 nanoparticles into the 3D structure of cellulose aerogels by virtue of a facile and cheap hydrothermal method. Comparative studies indicate that the RhB decolorization ratio is much higher in co-presence of Fe 3 O 4 and H 2 O 2 than that in presence of Fe 3 O 4 or H 2 O 2 only, revealing that the Fe 3 O 4 @CA-catalyzed Fenton-like reaction governed the RhB decolorization process. It was also found that almost 100% RhB removal was achieved in the Fenton-like system. Moreover, the composite exhibited higher catalytic activity than that of the individual Fe 3 O 4 particles. In addition, the Fe 3 O 4 @CA catalyst retained ∼97% of its ability to degrade RhB after the six successive degradation experiments, suggesting its excellent reusability. All these merits indicate that the green and low-cost catalyst with strong magnetic responsiveness possesses good potential for H 2 O 2 -driven Fenton-like treatment of organic dyestuff wastewater. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Payment methods for outpatient care facilities

    Science.gov (United States)

    Yuan, Beibei; He, Li; Meng, Qingyue; Jia, Liying

    2017-01-01

    Background Outpatient care facilities provide a variety of basic healthcare services to individuals who do not require hospitalisation or institutionalisation, and are usually the patient's first contact. The provision of outpatient care contributes to immediate and large gains in health status, and a large portion of total health expenditure goes to outpatient healthcare services. Payment method is one of the most important incentive methods applied by purchasers to guide the performance of outpatient care providers. Objectives To assess the impact of different payment methods on the performance of outpatient care facilities and to analyse the differences in impact of payment methods in different settings. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL), 2016, Issue 3, part of the Cochrane Library (searched 8 March 2016); MEDLINE, OvidSP (searched 8 March 2016); Embase, OvidSP (searched 24 April 2014); PubMed (NCBI) (searched 8 March 2016); Dissertations and Theses Database, ProQuest (searched 8 March 2016); Conference Proceedings Citation Index (ISI Web of Science) (searched 8 March 2016); IDEAS (searched 8 March 2016); EconLit, ProQuest (searched 8 March 2016); POPLINE, K4Health (searched 8 March 2016); China National Knowledge Infrastructure (searched 8 March 2016); Chinese Medicine Premier (searched 8 March 2016); OpenGrey (searched 8 March 2016); ClinicalTrials.gov, US National Institutes of Health (NIH) (searched 8 March 2016); World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (searched 8 March 2016); and the website of the World Bank (searched 8 March 2016). In addition, we searched the reference lists of included studies and carried out a citation search for the included studies via ISI Web of Science to find other potentially relevant studies. We also contacted authors of the main included studies regarding any further published or unpublished work. Selection criteria Randomised

  2. rGO-ZnO nanocomposites for high electrocatalytic effect on water oxidation obtained by microwave-hydrothermal method

    Science.gov (United States)

    Romeiro, Fernanda C.; Rodrigues, Mônica A.; Silva, Luiz A. J.; Catto, Ariadne C.; da Silva, Luis F.; Longo, Elson; Nossol, Edson; Lima, Renata C.

    2017-11-01

    Reduced graphene oxide-zinc oxide (rGO-ZnO) nanocomposites were successfully synthesized using a facile microwave-hydrothermal method under mild conditions, and their electrocatalytic properties towards O2 evolution were investigated. The microwave radiation played an important role in obtainment of well dispersed ZnO nanoparticles directly on reduced graphene oxide sheets without any additional reducing reagents or passivation agent. X-ray diffraction (XRD), Raman and infrared spectroscopies indicated the reduction of GO as well as the successful synthesis of rGO-ZnO nanocomposites. The chemical states of the samples were shown by XPS analyses. Due to the synergic effect, the resulting nanocomposites exhibited high electronic interaction between ZnO and rGO sheets, which improved the electrocatalytic oxidation of water with low onset potential of 0.48 V (vs. Ag/AgCl) in neutral pH and long-term stability, with high current density during electrolysis. The overpotential for water oxidation decreased in alkaline pH, suggesting useful insight on the catalytic mechanism for O2 evolution.

  3. Electrical conductivity characteristic of TiO2 nanowires from hydrothermal method

    International Nuclear Information System (INIS)

    Othman, Mohd Azlishah; Amat, Noor Faridah; Ahmad, Badrul Hisham; Rajan, Jose

    2014-01-01

    One dimensional nanostructures of titanium dioxide (TiO 2 ) were synthesized via hydrothermal method by mixing TiO 2 as precursor in aqueous solution of NaOH as solvent. Then, heat and washing treatment was applied. Thus obtained wires had diameter ∼15 nm. TiO 2 nanowires will be used as a network in solar cell such dye-sensitized solar cell in order to improve the performance of electron movement in the device. To improve the performance of electron movement, the characteristics of TiO 2 nanowires have been analyses using field emission scanning electron microscopy (FESEM) analysis, x-ray diffractometer (XRD) analysis and brunauer emmett teller (BET) analysis. Finally, electrical conductivity of TiO 2 nanowires was determined by measuring the resistance of the TiO 2 nanowires paste on microscope glass.

  4. Template-directed synthesis of MS (M=Cd, Zn) hollow microsphere via hydrothermal method

    Science.gov (United States)

    Wang, Shi-Ming; Wang, Qiong-Sheng; Wan, Qing-Li

    2008-05-01

    CdS, ZnS hollow microspheres were prepared with chitosan as the synthesis template at 140 and 150 °C, respectively, by hydrothermal method. The resultant products were characterized by X-ray diffraction (XRD) measurements in order to determine the crystalline phase of the products. The structural and morphological features of the nanoparticles were investigated by transmission electron microscopy (TEM) and ultraviolet-visible diffuse reflection spectroscopy (DRS). The experimental results indicated that all the nanoparticles aggregated into hollow microspheres and chitosan as a template played an important role in the formation of hollow microspheres. In addition, an intermediate complex structure-controlling possible reaction mechanism was proposed in this paper.

  5. The influence of sodium lauryl sulfate on the crystal phases of titania by hydrothermal method

    Science.gov (United States)

    Liu, Chaohong; Wang, Xin

    2012-11-01

    In this paper, we prepared TiO2 nanostructures by a hydrothermal method and investigated the influence of the SO4^{2-} ion and the effect of long alkyl chains of sodium dodecyl sulfate on the crystal phases of TiO2 by experiments and theoretical calculations. The results indicate that the absorption of the H+HSO4 fragment on rutile (110) is more stable than that of the 2H+SO4 fragment and more favorable to the formation of anatase. The absorption and steric effects of sodium dodecyl sulfate on the surfaces of TiO2 grains also have an important influence on the formation of mixed crystals by changing the speed and the way of octahedral TiO6 units combining. Based on the above facts, we revised the original reaction scheme for crystalline titania formation by previous authors.

  6. CuO urchin-nanostructures synthesized from a domestic hydrothermal microwave method

    International Nuclear Information System (INIS)

    Keyson, D.; Volanti, D.P.; Cavalcante, L.S.; Simoes, A.Z.; Varela, J.A.; Longo, E.

    2008-01-01

    This letter reports the synthesis of CuO urchin-nanostructures by a simple and novel hydrothermal microwave method. The formation and growth of urchin-nanostructures is mainly affected by the addition of polyethylene glycol (PEG). The hierarchical malachite particles are uniform spheres with a diameter of 0.7-1.9 μm. CuO urchin-nanostructures were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FEG-SEM) and nitrogen adsorption (BET). The specific surface area of the CuO nanostructured microspheres was about 170.5 m 2 /g. A possible mechanism for the formation of such CuO urchin-nanostructures is proposed

  7. A facile one-pot hydrothermal approach for the preparation of CuO/rGO nanocomposites with different morphologies

    Science.gov (United States)

    Ajit, Akshata V.; Gawli, Yogesh P.; Ethiraj, Anita Sagadevan

    2018-05-01

    Graphene-based metal oxides such as Cu2O, SnO2, CuO, Fe3O4, MnO2 are promising candidates for many applications because of their advantageous properties. Amongst all, CuO has been widely studied because of its excellent electrocatalytic activity. Although many methodologies have been developed for the synthesis of CuO/graphene nanostructures with different morphologies including nanorods, nanoparticles, nanosheets, flower, urchin; not many investigations have been done on one pot synthesis method for CuO/reduced graphene oxide (rGO) nanocomposites to achieve different morphologies. Therefore in the present work effort has been made to synthesize various CuO-rGO nanocomposites via surfactant (CTAB) assisted hydrothermal method. Detailed study was performed to monitor the effect of various reaction parameters like temperature, reaction time, reactant concentration on the synthesized nanocomposites. Several analytical tools, including XRD, SEM, FTIR and UV-Vis spectroscopy have been utilized to characterize the samples. XRD results showed formation of monoclinic structure of CuO along with presence of rGO. Calculated optical bandgap studies indicate decrease in the bandgap of synthesized CuO (Eg=4.5eV-4.34eV) with increase in temperature from 120°C to 180°C. Our results clearly demonstrate that reaction parameters play a key role to bring out the optical and morphological changes in the CuO-rGO nanocomposites.

  8. Abnormal room temperature ferromagnetism in CuO/ZnO nanocomposites via hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ping; Zhou, Wei; Li, Ying; Wang, Jianchun; Wu, Ping, E-mail: pingwu@tju.edu.cn

    2017-03-31

    Highlights: • CuO/ZnO nanocomposites have been synthesized by a one-step hydrothermal method. • The interaction between ZnO and CuO causes a modification of electronic structure. • The abnormal RTFM is discovered at the interface of CuO/ZnO. • The M{sub S} can be tuned by changing the phase ratios of the CuO and ZnO. • The indirect double-exchange model was employed to explain the origin of magnetism. - Abstract: CuO/ZnO nanocomposites have been successfully synthesized by a one-step hydrothermal method with different phase ratios. Field emission scanning electron microscopy and transmission electron microscopy results show that the obtained products of nanosheets are composed of small primary particles with an average size of about 20 nm. With the increasing proportion of CuO phase, nanosheets have significant collapse and the amount of small sheets increases obviously. The abnormal room temperature ferromagnetism was discovered at the interface between diamagnetic ZnO and antiferromagnetic CuO, which can be tuned by changing the phase ratios. Optical spectra indicate that the interaction between ZnO and CuO modifies the electronic structure of nanocomposites. XPS results verify the valence change of Cu ions and the presence of oxygen vacancies, which are ultimately responsible for the observed ferromagnetism. The indirect double-exchange model was employed to explain the origin of magnetism. Our study suggests that magnetically functional interfaces exhibit very appealing properties for novel devices.

  9. Human factors methods in DOE nuclear facilities

    International Nuclear Information System (INIS)

    Bennett, C.T.; Banks, W.W.; Waters, R.J.

    1993-01-01

    The US Department of Energy (DOE) is in the process of developing a series of guidelines for the use of human factors standards, procedures, and methods to be used in nuclear facilities. This paper discusses the philosophy and process being used to develop a DOE human factors methods handbook to be used during the design cycle. The following sections will discuss: (1) basic justification for the project; (2) human factors design objectives and goals; and (3) role of human factors engineering (HFE) in the design cycle

  10. Facile Synthesis of Nickel Chromite Nanostructures by Hydrothermal Route for Photocatalytic Degradation of Acid Black 1 under Visible Light

    Directory of Open Access Journals (Sweden)

    F. Beshkar

    2015-01-01

    Full Text Available NiCr2O4 normal spinel nanostructures were prepared via hydrothermal treatment at 180 °C for 12 h in the presence of cetyltrimethylammonium bromide (CTAB, sodium dodecyl sulphate (SDS and poly vinylpyrrolidone-25000 (PVP-25000 as capping agents and subsequent calcination process at 500 °C for 3 h . In this method, [Ni(en2(H2O2](NO32 and [Cr(en3]Cl3.3H2O used as precursors and not utilized any alkaline or precipitating agent. Detailed characterization of  the as-prepared nanostructures were carried out by Fourier transform infrared (FTIR, X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, UV-Vis diffuse reflectance spectroscopy (DRS. XRD revealed the formation of pure nickel chromite spinel phase and SEM showed the formation of uniform sphere-like nanoparticles. Furthermore, the photocatalytic degradation of acid black 1 as diazo dye used in textile and dyeing water pollutants was Investigated.

  11. Facile hydrothermal synthesis of alpha manganese sesquioxide ({alpha}-Mn{sub 2}O{sub 3}) nanodumb-bells: Structural, magnetic, optical and photocatalytic properties

    Energy Technology Data Exchange (ETDEWEB)

    Gnanam, S., E-mail: gnanam.nanoscience@gmail.com [Department of Physics, Presidency College, Chennai 600005, Tamilnadu (India); Rajendran, V. [Department of Physics, Presidency College, Chennai 600005, Tamilnadu (India)

    2013-02-15

    Highlights: Black-Right-Pointing-Pointer {alpha}-Mn{sub 2}O{sub 3} nanoparticles sizes of 35-42 nm have been prepared by hydrothermal process. Black-Right-Pointing-Pointer Shapes of {alpha}-Mn{sub 2}O{sub 3}: Dumb-bell, Cauliflower, spherical with rod, spherical with wires. Black-Right-Pointing-Pointer The strong UV emission can be attributed to high purity and perfect crystallinity. Black-Right-Pointing-Pointer Photocatalytic activity of {alpha}-Mn{sub 2}O{sub 3} was studied by degradation of Remazol red B dye. - Abstract: Nanometer scale cubic bixbyite {alpha}-Mn{sub 2}O{sub 3} has been synthesized by a facile hydrothermal method, at a temperature of 450 Degree-Sign C in the presence of various surfactants. The X-ray diffraction (XRD) analysis shows that the average crystallite size of the sample is {approx}35-42 nm. The shapes of the {alpha}-Mn{sub 2}O{sub 3} nanoparticles include: Dumb-bell-like (anionic surfactant), Cauliflower-like (nonionic surfactant), spherical with rods (cationic surfactant) and spherical with wires (surface modifier). The shapes of {alpha}-Mn{sub 2}O{sub 3} nanoparticles depend on the type of surfactant used in the synthesis. The magnetic property of the anionic surfactant assisted sample was primarily studied, using the vibrating sample magnetometer (VSM). The optical absorption spectra confirmed the effectiveness of the selected capping agents, as the anionic capped {alpha}-Mn{sub 2}O{sub 3} colloids absorbed at shorter wavelength than the other agents, indicating a much smaller crystallite size. The property of strong UV emissions may be attributed to the high purity and perfect crystallinity of the as-prepared {alpha}-Mn{sub 2}O{sub 3}. The surfactants-assisted catalyst was tested for its photocatalytic activity towards the photodegradation of the harmful organic dye Remazol Red B, using a multilamp photo reactor. Possible formation mechanisms have also been proposed for the as-synthesized anionic surfactant assisted samples.

  12. Magnetic properties and phase transformations of iron sulfides synthesized under the hydrothermal method

    Science.gov (United States)

    Li, S. H.; Chen, Y. H.

    2016-12-01

    The iron sulfide nano-minerals possess advantages of high abundance, low cost, and low toxicity. These advantages make them be competitive in the magnetic, electronic, and photoelectric applications. Mackinawite can be used in soil or water remediations. Greigite is very important for paleomagnetic and geochemical environment studies and the anode materials for lithium ion batteries. Besides, greigite is also utilized for hyperthermia and biomedicine. Pyrrhotite can be applied as geothermometry. Due to the above-mentioned reasons, iron sulfide minerals have specific significances and they must be further investigated, like their phase transformations, magnetic properties, and etc. In this study, the iron sulfide minerals were synthesized by using a hydrothermal method. The ex-situ and in-situ X-ray diffraction (XRD) was used to examine the crystal structure and phase transformation of iron sulfide minerals. The Transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) were carried out to investigate their morphology and magnetic properties, respectively. The results suggested that the phase transformation sequence was followed the order: mackinawite → greigite → (smythite) → pyrrhotite. Two pure mineral phases of greigite and pyrrhotite were obtained under the hydrothermal conditions. The morphology of the pure greigite is granular aggregates with a particle size of approximately 30 nm and pyrrhotite presented a hexagonal sheet stacking with a particle size of thousands nanometers. The greigite had a ferri-magnetic behavior and pyrrhotite was weak ferro-magnetic. Both of them had a pseudo-single magnetic domain (PSD) based on the Day's plot from SQUID data. The complete phase-transformation pathways and high magnetization of iron sulfide minerals are observed in this study and these kind of iron sulfide minerals are worthy to further study.

  13. Influence of fluorine substitution on the morphology and structure of hydroxyapatite nanocrystals prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Nathanael, A., E-mail: ajosephnc@yahoo.com [Department of Nanomaterials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Hong, S.I., E-mail: sihong@cnu.ac.kr [Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Masuda, Y. [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Rhee, Y.H.; Kim, H.W. [Department of Microbiology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2013-01-15

    Hydroxyapatite (HAp) nanocrystals with different levels of fluorine substitution (P/F = 0, 6, 4 and 2) on the OH sites were produced via hydrothermal method. The fluorine substitution was found to alter the morphology of crystals appreciably. The aspect ratio and the crystallinity of HAp crystals increased with increasing fluorine substitution. The presence of broad ring and hallow ring patterns in electron diffraction suggests the low-crystalline nature of HAp crystals. With increasing fluorine substitution, the diffraction patterns exhibited discrete rings and numerous diffraction spots, implying the increased crystallinity. Raman spectra from the HAp nanoparticles also support the less-crystalline nature of the pristine HAp and the enhanced crystallization by fluorine substitution. In HAp crystals processed with no fluorine substitution, surface energy and planar Ca{sup 2+} density are less sensitive to the crystallographic orientation because of its low-crystalline nature, favoring equi-axed or slightly elongated particles. The addition of fluorine apparently increased the crystallinity, enhancing the orientation dependent growth and accordingly the aspect ratio. Osteoblast proliferation was observed to be enhanced by fluorine substitution in HAp. In vitro biological data support that the excellent osteoblastic cell viability and functional activity of the fluoridated apatite. -- Highlights: Black-Right-Pointing-Pointer Fluorapatite nanorods were produced hydrothermally with different fluorine content. Black-Right-Pointing-Pointer Fluorine substitution was found to alter the morphology of crystals appreciably. Black-Right-Pointing-Pointer It enhances the crystallinity, orientation dependent growth and hence aspect ratio. Black-Right-Pointing-Pointer In vitro cellular analysis shows excellent cell viability of the fluorapatite.

  14. Payment methods for outpatient care facilities.

    Science.gov (United States)

    Yuan, Beibei; He, Li; Meng, Qingyue; Jia, Liying

    2017-03-03

    Outpatient care facilities provide a variety of basic healthcare services to individuals who do not require hospitalisation or institutionalisation, and are usually the patient's first contact. The provision of outpatient care contributes to immediate and large gains in health status, and a large portion of total health expenditure goes to outpatient healthcare services. Payment method is one of the most important incentive methods applied by purchasers to guide the performance of outpatient care providers. To assess the impact of different payment methods on the performance of outpatient care facilities and to analyse the differences in impact of payment methods in different settings. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), 2016, Issue 3, part of the Cochrane Library (searched 8 March 2016); MEDLINE, OvidSP (searched 8 March 2016); Embase, OvidSP (searched 24 April 2014); PubMed (NCBI) (searched 8 March 2016); Dissertations and Theses Database, ProQuest (searched 8 March 2016); Conference Proceedings Citation Index (ISI Web of Science) (searched 8 March 2016); IDEAS (searched 8 March 2016); EconLit, ProQuest (searched 8 March 2016); POPLINE, K4Health (searched 8 March 2016); China National Knowledge Infrastructure (searched 8 March 2016); Chinese Medicine Premier (searched 8 March 2016); OpenGrey (searched 8 March 2016); ClinicalTrials.gov, US National Institutes of Health (NIH) (searched 8 March 2016); World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (searched 8 March 2016); and the website of the World Bank (searched 8 March 2016).In addition, we searched the reference lists of included studies and carried out a citation search for the included studies via ISI Web of Science to find other potentially relevant studies. We also contacted authors of the main included studies regarding any further published or unpublished work. Randomised trials, non-randomised trials, controlled before

  15. Free-polymer controlling morphology of α-MoO3 nanobelts by a facile hydrothermal synthesis, their electrochemistry for hydrogen evolution reactions and optical properties

    International Nuclear Information System (INIS)

    Sinaim, Hathai; Ham, Dong Jin; Lee, Jae Sung; Phuruangrat, Anukorn; Thongtem, Somchai; Thongtem, Titipun

    2012-01-01

    Highlights: ► MoO 3 nanobelts as an n-type semiconducting material. ► It was successfully synthesized by a facile hydrothermal reaction. ► A promising material with 3.75 eV band gap for hydrogen evolution reaction (HER). - Abstract: Orthorhombic molybdenum oxide (α-MoO 3 ) nanobelts were successfully synthesized by the 100–180 °C and 2–20 h hydrothermal reactions of (NH 4 ) 6 Mo 7 O 24 ·4H 2 O solutions containing 15 ml 2 M acid (HNO 3 , H 2 SO 4 or HCl) with no surfactant and template adding. These products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopy, and electron microscopy (EM). In the present research, the product synthesized by the 180 °C and 20 h hydrothermal reaction of the solution containing HNO 3 was α-MoO 3 nanobelts with >10 μm long and 3 nanobelts were characterized by linear sweep voltammetry (LSV) and Tafel plot, including UV–vis and photoluminescence (PL) spectroscopy. These imply that α-MoO 3 nanobelts show satisfied performance for HER, with the 3.75 eV direct allowed band gap (E g ) due to the charged transition of O 2p → Mo 4d , including the emission of 437 nm wavelength at room temperature.

  16. Preparation and magnetic properties of nano size nickel ferrite particles using hydrothermal method

    Directory of Open Access Journals (Sweden)

    Nejati Kamellia

    2012-03-01

    Full Text Available Abstract Background Nickel ferrite, a kind of soft magnetic materials is one of the most attracting class of materials due to its interesting and important properties and has many technical applications, such as in catalysis, sensors and so on. In this paper the synthesis of NiFe2O4 nanoparticles by the hydrothermal method is reported and the inhibition of surfactant (Glycerol or Sodium dodecyl sulfate on the particles growth is investigated. Methods For investigation of the inhibition effect of surfactant on NiFe2O4 particles growth, the samples were prepared in presence of Glycerol and Sodium dodecyl sulfate. The X-ray powder diffraction (XRD, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FT-IR, vibrating sample magnetometer (VSM and inductively coupled plasma atomic emission spectrometer (ICP-AES techniques were used to characterize the samples. Results The results of XRD and ICP-AES show that the products were pure NiFe2O4 and also nanoparticles grow with increasing the temperature, while surfactant prevents the particle growth under the same condition. The average particle size was determined from the Scherrer's equation and TEM micrographs and found to be in the range of 50-60 nm that decreased up to 10-15 nm in presence of surfactant. The FT-IR results show two absorption bands near to 603 and 490 cm-1 for the tetrahedral and octahedral sites respectively. Furthermore, the saturated magnetization and coercivity of NiFe2O4 nanoparticles were in the range of 39.60 emu/g and 15.67 Qe that decreased for samples prepared in presence of surfactant. As well as, the nanoparticles exhibited a superparamagnetic behavior at room temperature. Conclusions Nanosized nickel ferrite particles were synthesized with and without surfactant assisted hydrothermal methods. The results show that with increasing of temperature, the crystallinity of nanoparticles is increased. In the presence of surfactants, the crystallinity of

  17. Flower-like CuO synthesized by CTAB-assisted hydrothermal method

    Indian Academy of Sciences (India)

    Administrator

    and crystalline structure, the control of the shape and size of the semiconductors ... hydrothermal process using copper threads as precursor and pointed out ... 2.3 Instrumentation. Power X-ray .... Measurement of Tianjin University. References.

  18. Systematic study on surface and magnetostructural changes in Mn-substituted dysprosium ferrite by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Rekha, G. [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Tholkappiyan, R. [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Department of Physics, College of Science, UAE University, Al-Ain 15551 (United Arab Emirates); Vishista, K., E-mail: raovishista@gmail.com [Department of Physics, College of Engineering Guindy, Anna University, Sardar Patel Road, Chennai 600025 (India); Hamed, Fathalla [Department of Physics, College of Science, UAE University, Al-Ain 15551 (United Arab Emirates)

    2016-11-01

    Highlights: • Garnet type Dy{sub 3}Fe{sub 5-x}Mn{sub x}O{sub 12} (x = 0–0.06) nanoparticles of 88.4–86.8 nm were synthesized by hydrothermal method. • The Dy, Mn, Fe and O elements in the ferrites were confirmed from XPS. • The multiple oxidation states of Fe and Mn ions, bonding energy and cationic distributions of the samples were examined by XPS. • The magnetic property shows ferromagnetic behavior from VSM technique. • The results from these studies are correlated with respect to Mn dopant. - Abstract: Dysprosium iron garnets are of scientific importance because of the wide range of magnetic properties that can be obtained in substituting dysprosium by a rare earth metal. In the present work, the effect of Mn substitution on magnetostructural changes in dysprosium ferrite nanoparticles is studied. Highly crystalline pure and Mn doped dysprosium ferrite nanoparticles were synthesized by hydrothermal method. The samples were calcined at 1100 °C for 2 h in air atmosphere which is followed by characterization using XRD, FT-IR analysis, SEM, XPS and VSM. The average crystallite size of synthesized samples were calculated by X-ray diffraction falls in the range of 88.4–86.8 nm and was found to be in cubic garnet structure. For further investigation of the structure and corresponding changes in the tetrahedral and octahedral stretching vibrational bonds, FT-IR was used. The synthesized samples consist of multiple oxidation (Fe{sup 3+} and Fe{sup 2+}) states for Fe ions and (Mn{sup 3+} and Mn{sup 2+}) Mn ions analyzed in three ways of Fe 2p and Mn 2p spectra from the XPS analysis. With respect to Mn dopant in Dy{sub 3}Fe{sub 5}O{sub 12}, the cationic distributions of elements were discussed from high resolution XPS spectra by peak position and shift, area, width. To find out the porous/void surface morphology of the sample, scanning electron microscopy was used. From XPS analysis, the presence of elements (Dy, Mn, Fe and O) and their composition in the

  19. Detection of nitrite based on fluorescent carbon dots by the hydrothermal method with folic acid

    Science.gov (United States)

    Lin, Haitao; Ding, Liyun; Zhang, Bingyu; Huang, Jun

    2018-05-01

    A fluorescent carbon dots probe for the detection of aqueous nitrite was fabricated by a one-pot hydrothermal method, and the transmission electron microscope, X-ray diffractometer, UV-Vis absorption spectrometer and fluorescence spectrophotometer were used to study the property of carbon dots. The fluorescent property of carbon dots influenced by the concentration of aqueous nitrite was studied. The interaction between the electron-donating functional groups and the electron-accepting nitrous acid could account for the quenching effect on carbon dots by adding aqueous nitrite. The products of the hydrolysis of aqueous nitrite performed a stronger quenching effect at lower pH. The relationship between the relative fluorescence intensity of carbon dots and the concentration of nitrite was described by the Stern-Volmer equation (I0/I - 1 = 0.046[Q]) with a fine linearity (R2 = 0.99). The carbon dots-based probe provides a convenient method for the detection of nitrite concentration.

  20. Immobilization of nanoparticle titanium dioxide membrane on polyamide fabric by low temperature hydrothermal method

    International Nuclear Information System (INIS)

    Zhang Hui; Yang Lu

    2012-01-01

    A thin layer of nanoparticle titanium dioxide was immobilized on polyamide 6 (PA6) fiber using titanium sulfate and urea at low temperature hydrothermal condition. The titanium dioxide loaded fabric was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry and thermal gravimetry techniques. The optical and mechanical properties, water absorption and degradation of methylene blue dye under ultraviolet (UV) irradiation of the PA6 fabric before and after treatments were also examined. It was found that when PA6 fabric was treated in titanium sulfate and urea aqueous solution, anatase nanocrystalline titanium dioxide was synthesized and simultaneously adhered onto the fiber surface. The average crystal size of titanium dioxide nanoparticles was about 13.2 nm. The thermal behavior of PA6 fiber distinctly changed and the onset decomposition temperature decreased. As compared with the untreated fabric, the protection against UV radiation was improved. The water absorbency increased slightly. As the fabric dimensions were reduced in warp and weft directions, the breaking load and tensile strain increased to some extent. The titanium dioxide coated fabric could degradate methylene blue dye under UV irradiation. - Highlights: ► We employed a method to immobilize TiO 2 nanoparticle on polyamide fiber. ► We fabricated the TiO 2 -coated polyamide fabric with the photocatalytic activity. ► The modification method may be suitable for the potential applications.

  1. Three-dimensional sea-urchin-like hierarchical TiO{sub 2} microspheres synthesized by a one-pot hydrothermal method and their enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Yi, E-mail: zhouyihn@163.com [Department of Chemical and Biological Engineering, Changsha University of Science and Technology, Hunan, 410114 (China); Huang, Yan; Li, Dang; He, Wenhong [Department of Chemical and Biological Engineering, Changsha University of Science and Technology, Hunan, 410114 (China)

    2013-07-15

    Graphical abstract: SEM images of the samples synthesized at different hydrothermal temperatures for 8 h: (a) 75; (b) 100; (c) 120; and (d) 140°C, followed by calcination at 450 °C for 2 h. Highlights: ► Effects of calcination temperature on the phase transformation were studied. ► Effects of hydrothermal temperature and time on the morphology growth were studied. ► A two-stage reaction mechanism for the formation was presented. ► The photocatalytic activity was evaluated under sunlight irradiation. ► Effects of calcination temperature on the photocatalytic activity were studied. - Abstract: Novel three-dimensional sea-urchin-like hierarchical TiO{sub 2} superstructures were synthesized on a Ti plate in a mixture of H{sub 2}O{sub 2} and NaOH aqueous solution by a facile one-pot hydrothermal method at a low temperature, followed by protonation and calcination. The results of series of electron microscopy characterizations suggested that the hierarchical TiO{sub 2} superstructures consisted of numerous one-dimensional nanostructures. The microspheres were approximately 2–4 μm in diameter, and the one-dimensional TiO{sub 2} nanostructures were up to 600–700 nm long. A two-stage reaction mechanism, i.e., initial growth and then assembly, was proposed for the formation of these architectures. The three-dimensional sea-urchin-like hierarchical TiO{sub 2} microstructures showed excellent photocatalytic activity for the degradation of Rhodamine B aqueous solution under sunlight irradiation, which was attributed to the special three-dimensional hierarchical superstructure, and increased number of surface active sites. This novel superstructure has promising use in practical aqueous purification.

  2. Void Structures in Regularly Patterned ZnO Nanorods Grown with the Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Yu-Feng Yao

    2014-01-01

    Full Text Available The void structures and related optical properties after thermal annealing with ambient oxygen in regularly patterned ZnO nanrorod (NR arrays grown with the hydrothermal method are studied. In increasing the thermal annealing temperature, void distribution starts from the bottom and extends to the top of an NR in the vertical (c-axis growth region. When the annealing temperature is higher than 400°C, void distribution spreads into the lateral (m-axis growth region. Photoluminescence measurement shows that the ZnO band-edge emission, in contrast to defect emission in the yellow-red range, is the strongest under the n-ZnO NR process conditions of 0.003 M in Ga-doping concentration and 300°C in thermal annealing temperature with ambient oxygen. Energy dispersive X-ray spectroscopy data indicate that the concentration of hydroxyl groups in the vertical growth region is significantly higher than that in the lateral growth region. During thermal annealing, hydroxyl groups are desorbed from the NR leaving anion vacancies for reacting with cation vacancies to form voids.

  3. Synthesis and growth mechanism of sponge-like nickel using a hydrothermal method

    Science.gov (United States)

    Shao, Bin; Yin, Xueguo; Hua, Weidong; Ma, Yilong; Sun, Jianchun; Li, Chunhong; Chen, Dengming; Guo, Donglin; Li, Kejian

    2018-05-01

    Sponge-like nickel composed of micro-chains with a diameter of 1-5 μm was selectively synthesized by the hydrothermal method, using sodium hydroxide (NaOH) as the alkaline reagent, aqueous hydrazine as reducing agent and citric acid as a coordination agent. The time-dependent samples prepared at different NaOH concentrations were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FTIR). The results showed that the agglomerates of nickel citrate hydrazine complex nanoplates were first precipitated and then reduced to prickly nickel micro-chains at a lower NaOH concentration, which played a role in the further formation of sponge-like nickel. Also, the probable growth mechanism of the sponge-like nickel was proposed. The magnetic properties of sponge-like nickel were studied using a vibrating sample magnetometer. The sponge-like nickel exhibited a ferromagnetic behavior with a saturation magnetization value of 43.8 emu g-1 and a coercivity value of 120.7 Oe.

  4. Synthesis and spectroscopic study of CdS nanoparticles using hydrothermal method

    Science.gov (United States)

    AL-Mamoori, Mohammed H. K.; Mahdi, Dunia K.; Al-Shrefi, Saif M.

    2018-05-01

    In this work, cadmium sulfide nanoparticles (powder) with diameter 50.8 nm was prepared using hydrothermal method. The structural and optical properties of CdS nanoparticles was studied by X-ray diffraction, FESEM, EDS, FTIR, UV-Diffuse Reflectance spectroscopy and Photoluminance spectrum. X-ray diffraction reveal the formation the purity of prepared phase of CdS particles with hexagonal wurtzite structure with particle size 31.8nm by using sheerer equation. The energy dispersion scattering (EDS) examination explains that the sample is composed of a large amount of Cd and S which are exactly CdS nanoparticles and there is a very small trace of (Zn) and (O) element observed because of there is a small pollutions in the measurement place of samples. FESEM shows the spherical shape of nanoparticles with around 50.8 nm diameter. The optical absorption spectral study identified the red shift of the sample in comparison to bulk ZnO in three dimensions. Photoluminance spectrum (PL) at room temperature showed that there are two luminescence peaks at 433.14 nm and 518.21nm. Samples demonstrate a sharp emission band at around 433.18 nm, which is attributed to the typical exciton luminescence. The broad band at 518.21nm which were attributed to the trapped luminescence. The green emission band at 518.21 nm was associated with the emission due to electronic transition from the conduction band to an accepter level due to interstitial sulphur ion.

  5. A Simple and Efficient RNA Extraction Method from Deep-Sea Hydrothermal Vent Chimney Structures.

    Science.gov (United States)

    Muto, Hisashi; Takaki, Yoshihiro; Hirai, Miho; Mino, Sayaka; Sawayama, Shigeki; Takai, Ken; Nakagawa, Satoshi

    2017-12-27

    RNA-based microbiological analyses, e.g., transcriptome and reverse transcription-quantitative PCR, require a relatively large amount of high quality RNA. RNA-based analyses on microbial communities in deep-sea hydrothermal environments often encounter methodological difficulties with RNA extraction due to the presence of unique minerals in and the low biomass of samples. In the present study, we assessed RNA extraction methods for deep-sea vent chimneys that had complex mineral compositions. Mineral-RNA adsorption experiments were conducted using mock chimney minerals and Escherichia coli total RNA solution, and showed that detectable RNA significantly decreased possibly due to adsorption onto minerals. This decrease in RNA was prevented by the addition of sodium tripolyphosphate (STPP), deoxynucleotide triphosphates (dNTPs), salmon sperm DNA, and NaOH. The addition of STPP was also effective for RNA extraction from the mixture of E. coli cells and mock chimney minerals when TRIzol reagent and the RNeasy column were used, but not when the RNeasy PowerSoil total RNA kit was used. A combination of STPP, TRIzol reagent, the RNeasy column, and sonication resulted in the highest RNA yield from a natural chimney. This indirect extraction procedure is simple, rapid, inexpensive, and may be used for large-scale RNA extraction.

  6. Thermal decomposition of synthetic antlerite prepared by microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Koga, Nobuyoshi [Chemistry Laboratory, Graduate School of Education, Hiroshima University, 1-1-1 Kagamiyama, Higashi-Hiroshima 739-8524 (Japan)], E-mail: nkoga@hiroshima-u.ac.jp; Mako, Akira; Kimizu, Takaaki; Tanaka, Yuu [Chemistry Laboratory, Graduate School of Education, Hiroshima University, 1-1-1 Kagamiyama, Higashi-Hiroshima 739-8524 (Japan)

    2008-01-30

    Copper(II) hydroxide sulfate was synthesized by a microwave-assisted hydrothermal method from a mixed solution of CuSO{sub 4} and urea. Needle-like crystals of ca. 20-30 {mu}m in length precipitated by irradiating microwave for 1 min were characterized as Cu{sub 3}(OH){sub 4}SO{sub 4} corresponding to mineral antlerite. The reaction pathway and kinetics of the thermal decomposition of the synthetic antlerite Cu{sub 3}(OH){sub 4}SO{sub 4} were investigated by means of thermoanalytical techniques complemented by powder X-ray diffractometry and microscopic observations. The thermal decomposition of Cu{sub 3}(OH){sub 4}SO{sub 4} proceeded via two separated reaction steps of dehydroxylation and desulfation to produce CuO, where crystalline phases of Cu{sub 2}OSO{sub 4} and CuO appeared as the intermediate products. The kinetic characteristics of the respective steps were discussed in comparison with those of the synthetic brochantite Cu{sub 4}(OH){sub 6}SO{sub 4} reported previously.

  7. Magnetic properties of α-Fe2O3 nanoparticle synthesized by a new hydrothermal method

    International Nuclear Information System (INIS)

    Giri, S.; Samanta, S.; Maji, S.; Ganguli, S.; Bhaumik, A.

    2005-01-01

    Nanoparticles of α-Fe 2 O 3 have been prepared using a hydrothermal synthesis method in aqueous-organic microemulsion under mild alkaline condition. The condensation reaction was optimized in the presence of a cationic surfactant cetyltrimethylammonium bromide (CTAB). It was found that the size and nature of the α-Fe 2 O 3 nanoparticle strongly depends on the pH, oxalic acid and CTAB as well as tetramethylammonium hydroxide (TMAOH, alkali source) concentrations. The uniformity of the particle size was checked by the transmission electron microscopy while the single phase of the nanocrystalline α-Fe 2 O 3 was characterized using powder X-ray diffraction. The Moessbauer study exhibited a sextet pattern with internal field smaller than that of the bulk counterpart. The temperature variation of magnetization showed a broad maximum at around 125 K while the field-cooled effect of the magnetization showed the branching between the field cooled and zero field cooled magnetization up to 340 K. A large anisotropy has been observed from the analysis of magnetization curve as well as from the large blocking temperature. The estimation of the particle size from the magnetization curve was found to be in close agreement with the TEM results

  8. Gas sensing properties of graphene–WO3 composites prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Chu, Xiangfeng; Hu, Tao; Gao, Feng; Dong, Yongping; Sun, Wenqi; Bai, Linshan

    2015-01-01

    Graphical abstract: - Highlights: • The amount of graphene had an effect on the morphology of graphene–WO 3 composites. • The optimum temperature of 0.1 wt% graphene–WO 3 sensor to acetaldehyde was 100 °C. • 0.1 wt% graphene–WO 3 sensor exhibited good selectivity to acetaldehyde at 100 °C. - Abstract: Graphene–WO 3 composites mixed with different amounts of graphene (0, 0.1, 0.5, 1 and 3 wt%) were prepared by hydrothermal method at 180 °C for 24 h. The as-prepared graphite oxide, graphene and graphene–WO 3 composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectra (FT-IR) and Raman spectroscopy, respectively. The effect of the amount of graphene in the composites on the gas-sensing responses and the gas-sensing selectivity of the materials was investigated. The experimental results revealed that the sensor based on 0.1 wt% graphene–WO 3 composite exhibited high response and good selectivity to acetaldehyde vapor at 100 °C, the optimum operating temperature of this sensor to 1000 ppm acetaldehyde vapor decreased from 180 °C to 100 °C comparing with that of pure WO 3 . The response time and the recovery time for 100 ppm acetaldehyde vapor were 250 s and 225 s, respectively

  9. Electric Properties of NaTaO3 Obtained by Hydrothermal Method

    Science.gov (United States)

    Malaescu, Dan; Grozescu, Ioan; Sfirloaga, Paula; Vlazan, Paulina; Marin, Catalin N.

    2015-12-01

    Two samples of NaTaO3 perovskite materials were prepared by the standard hydrothermal method at the same reaction temperature (600 °C) but with different sintering times: 6 hours for sample S1 and 12 hours for sample S2. Using X-ray diffraction (XRD), it shows that samples S1 and S2 are mixtures of Na-Ta oxides (Ta2O5 and the prevailing phase NaTaO3). The scanning electron microscopy analysis (SEM), shows that the grains are connected each other in agglomerated clusters of size about few hundred nanometers. The frequency (f) dependencies of complex impedance, Z(f) = Z'(f) - i Z''(f) of the samples, over the frequency range 20 Hz - 2 MHz, at room temperature are presented. The real component Z' of the complex impedance decreases with increasing frequency and the imaginary component Z'' has two maximum corresponding to two relaxation processes. The results obtained from the complex impedance spectroscopy, Z''(Z') showed the appearance of two semicircles, corresponding to grain and grain boundary mechanism. Experimental results have been fitted with two parallel RC equivalent circuits connected in series and the parameters R and C have been evaluated.

  10. Biocompatibility and antimicrobial activity of zinc(II doped hydroxyapatite, synthesized by hydrothermal method

    Directory of Open Access Journals (Sweden)

    Kojić Vesna

    2012-01-01

    Full Text Available In order to obtain multifunctional materials with good biocompatibility and antimicrobial effect, hydroxyapatite (HAp doped with Zn2+ was synthesized by hydrothermal method. Powders with different content of zinc ions were synthesized and compared with undoped HAp to investigation of Zn2+ ion influence on the antimicrobial activity of HAp. Analyses of undoped and Zn2+-doped powders before and after thermal treatment at 1200ºC were performed by SEM and XRD. Antimicrobial effects of powders were examined in relation to Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans in liquid medium. The results showed that the obtained powders have good antimicrobial activity, but higher antimicrobial activities of powders doped with Zn2+ were observed after annealing at 1200°C. For powders annealed at 1200°C in vitro biocompatibility tests MTT and DET with MRC-5 fibroblast cells in liquid medium were carried out. Based on MTT and DET tests it was shown that powders do not have a significant cytotoxic effect, which was confirmed by SEM analysis of MRC-5 fibroblast cells after theirs in vitro contact with powders. [Projekat Ministarstva nauke Republike Srbije, br. III 45019 and FP7-REGPOT-2009-1 NANOTECH FTM

  11. Synthesis of zinc oxide by microwave hydrothermal method for application to transesterification of soybean oil (biodiesel)

    Energy Technology Data Exchange (ETDEWEB)

    Quirino, Max Rocha [LABQUIM/Universidade Federal da Paraíba, Campus III, 58200-000, Bananeiras, PB (Brazil); Oliveira, Mateus José C. [DEMA/Universidade Federal de Campina Grande, Campina Grande, Campus I, 58429-900, Campina Grande, PB (Brazil); Keyson, Davy [DME/Universidade Federal da Paraíba, Campus – I, 58051-900, João Pessoa, PB (Brazil); Lucena, Guilherme Leocárdio, E-mail: guilhermelucena@cchsa.ufpb.br [LABQUIM/Universidade Federal da Paraíba, Campus III, 58200-000, Bananeiras, PB (Brazil); Oliveira, João Bosco L. [Universidade Federal do Rio Grande do Norte, Campus I, 59078-970, Natal, RN (Brazil); Gama, Lucianna [DEMA/Universidade Federal de Campina Grande, Campina Grande, Campus I, 58429-900, Campina Grande, PB (Brazil)

    2017-01-01

    ZnO nanostructures were synthesized by microwave hydrothermal treatment using two different mineralization agents (NaOH and NH{sub 4}OH), and were evaluated as catalysts for biodiesel synthesis. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. The XRD patterns indicated the formation of the hexagonal wurtzite phase in both samples. SEM analysis showed completely different morphologies based on the mineralization agent employed. The ZnO nanostructures synthesized with NaOH (ZONa5 and ZONa5P) presented plate-like agglomerates, resulting in a quasi-spherical morphology, whereas the materials synthesized with NH{sub 4}OH (ZONH5 and ZONH5P) presented a flower-like morphology. The ZONa5P sample showed an activity of 77.82% for the catalytic conversion of soybean oil into biodiesel by transesterification using methanol. - Highlights: • ZnO was synthesized by MH method in only 5 min. • The powders morphology is completely influenced by mineralization agent. • ZONa5P showed activity of 77.82% for the conversion of soybean oil into biodiesel.

  12. Optical properties of titanium-di-oxide (TiO2) prepared by hydrothermal method

    Science.gov (United States)

    Rahman, Kazi Hasibur; Biswas, Sayari; Kar, Asit Kumar

    2018-05-01

    Research on titanate and its derived TiO2 nanostructures with large specific surface area have received great attention due to their enhanced efficiency in photocatalysis, DSSC etc. Here, in this communication TiO2 powder has been prepared by hydrothermal method at 180 °C. In this work we have shown the changes in optical properties of the powder with two different sintering temperatures ‒ 500 °C and 800 °C. The as prepared powder was also studied. FESEM images show spherical particles for the as prepared samples which look more like agglomeration after sintering. Band gaps of the prepared samples were calculated from UV-Vis spectroscopy which lies in the range 2.85 eV ‒ 3.13 eV. The photoluminescence (PL) spectra of the prepared samples were recorded at room temperature in the range of 300‒700 nm. It shows two distinct peaks at 412 nm and 425 nm.

  13. Synthesis of zinc oxide by microwave hydrothermal method for application to transesterification of soybean oil (biodiesel)

    International Nuclear Information System (INIS)

    Quirino, Max Rocha; Oliveira, Mateus José C.; Keyson, Davy; Lucena, Guilherme Leocárdio; Oliveira, João Bosco L.; Gama, Lucianna

    2017-01-01

    ZnO nanostructures were synthesized by microwave hydrothermal treatment using two different mineralization agents (NaOH and NH 4 OH), and were evaluated as catalysts for biodiesel synthesis. The materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. The XRD patterns indicated the formation of the hexagonal wurtzite phase in both samples. SEM analysis showed completely different morphologies based on the mineralization agent employed. The ZnO nanostructures synthesized with NaOH (ZONa5 and ZONa5P) presented plate-like agglomerates, resulting in a quasi-spherical morphology, whereas the materials synthesized with NH 4 OH (ZONH5 and ZONH5P) presented a flower-like morphology. The ZONa5P sample showed an activity of 77.82% for the catalytic conversion of soybean oil into biodiesel by transesterification using methanol. - Highlights: • ZnO was synthesized by MH method in only 5 min. • The powders morphology is completely influenced by mineralization agent. • ZONa5P showed activity of 77.82% for the conversion of soybean oil into biodiesel.

  14. Facile Low Temperature Hydrothermal Synthesis of BaTiO3 Nanoparticles Studied by In Situ X-ray Diffraction

    Directory of Open Access Journals (Sweden)

    Ola G. Grendal

    2018-06-01

    Full Text Available Ferroelectric materials are crucial for today’s technological society and nanostructured ferroelectric materials are important for the downscaling of devices. Controlled and reproducible synthesis of these materials are, therefore, of immense importance. Hydrothermal synthesis is a well-established synthesis route, with a large parameter space for optimization, but a better understanding of nucleation and growth mechanisms is needed for full utilization and control. Here we use in situ X-ray diffraction to follow the nucleation and growth of BaTiO3 formed by hydrothermal synthesis using two different titanium precursors, an amorphous titania precipitate slurry and a Ti-citric acid complex solution. Sequential Rietveld refinement was used to extract the time dependency of lattice parameters, crystallite size, strain, and atomic displacement parameters. Phase pure BaTiO3 nanoparticles, 10–15 nm in size, were successfully synthesized at different temperatures (100, 125, and 150 °C from both precursors after reaction times, ranging from a few seconds to several hours. The two precursors resulted in phase pure BaTiO3 with similar final crystallite size. Finally, two different growth mechanisms were revealed, where the effect of surfactants present during hydrothermal synthesis is discussed as one of the key parameters.

  15. Photoluminescence of ZnS: Mn quantum dot by hydrothermal method

    Directory of Open Access Journals (Sweden)

    Yun Hu

    2018-01-01

    Full Text Available ZnS: Mn quantum dots (QDs with the average grain size from 4.2 to 7.2 nm were synthesized by a hydrothermal method. All samples were cubic zinc blende structure (β-ZnS measured using X-ray diffraction (XRD. And the main diffraction peaks of ZnS: Mn shifted slightly towards higher angle in comparison with the intrinsic ZnS because of the substitution of Mn2+ for Zn2+. Due to the small grain size (4-7 nm effect, the poor dispersion and serious reunion phenomenon for the samples were observed from transmission electron microscopy (TEM. ZnS: Mn QDs had four peaks centered at 466, 495, 522, and 554 nm, respectively, in the photoluminescence (PL spectra, in which the band at 554 nm absent in the intrinsic ZnS: Mn is attributed to the doping of Mn2+ in the lattice sites. As the concentration of Mn2+ increasing from 0% to 0.6 at%, the intensity of the PL emission also increased. But the concentration reached 0.9 at%, quenching of PL emission occurred. The peak in ZnS: Mn QDs observed at 490 cm-1 was originated from the stretching vibration of the Mn–O bonds in the Fourier transform infrared (FTIR spectra. And the small changes about this peak compared with the previous reports at 500 cm-1 can be attributed to the formation of quantum dots. This method we utilized to synthesize ZnS: Mn QDs is very simple, low cost, and applicable for other semiconductor QD materials.

  16. An improved quantum-behaved particle swarm optimization method for short-term combined economic emission hydrothermal scheduling

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Songfeng; Sun, Chengfu; Lu, Zhengding [School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2010-03-15

    This paper presents a modified quantum-behaved particle swarm optimization (QPSO) for short-term combined economic emission scheduling (CEES) of hydrothermal power systems with several equality and inequality constraints. The hydrothermal scheduling is formulated as a bi-objective problem: (i) minimizing fuel cost and (ii) minimizing pollutant emission. The bi-objective problem is converted into a single objective one by price penalty factor. The proposed method, denoted as QPSO-DM, combines the QPSO algorithm with differential mutation operation to enhance the global search ability. In this study, heuristic strategies are proposed to handle the equality constraints especially water dynamic balance constraints and active power balance constraints. A feasibility-based selection technique is also employed to meet the reservoir storage volumes constraints. To show the efficiency of the proposed method, different case studies are carried out and QPSO-DM is compared with the differential evolution (DE), the particle swarm optimization (PSO) with same heuristic strategies in terms of the solution quality, robustness and convergence property. The simulation results show that the proposed method is capable of yielding higher-quality solutions stably and efficiently in the short-term hydrothermal scheduling than any other tested optimization algorithms. (author)

  17. An improved quantum-behaved particle swarm optimization method for short-term combined economic emission hydrothermal scheduling

    Energy Technology Data Exchange (ETDEWEB)

    Lu Songfeng [School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Sun Chengfu, E-mail: ajason_369@sina.co [School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Lu Zhengding [School of Computer Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2010-03-15

    This paper presents a modified quantum-behaved particle swarm optimization (QPSO) for short-term combined economic emission scheduling (CEES) of hydrothermal power systems with several equality and inequality constraints. The hydrothermal scheduling is formulated as a bi-objective problem: (i) minimizing fuel cost and (ii) minimizing pollutant emission. The bi-objective problem is converted into a single objective one by price penalty factor. The proposed method, denoted as QPSO-DM, combines the QPSO algorithm with differential mutation operation to enhance the global search ability. In this study, heuristic strategies are proposed to handle the equality constraints especially water dynamic balance constraints and active power balance constraints. A feasibility-based selection technique is also employed to meet the reservoir storage volumes constraints. To show the efficiency of the proposed method, different case studies are carried out and QPSO-DM is compared with the differential evolution (DE), the particle swarm optimization (PSO) with same heuristic strategies in terms of the solution quality, robustness and convergence property. The simulation results show that the proposed method is capable of yielding higher-quality solutions stably and efficiently in the short-term hydrothermal scheduling than any other tested optimization algorithms.

  18. An improved quantum-behaved particle swarm optimization method for short-term combined economic emission hydrothermal scheduling

    International Nuclear Information System (INIS)

    Lu Songfeng; Sun Chengfu; Lu Zhengding

    2010-01-01

    This paper presents a modified quantum-behaved particle swarm optimization (QPSO) for short-term combined economic emission scheduling (CEES) of hydrothermal power systems with several equality and inequality constraints. The hydrothermal scheduling is formulated as a bi-objective problem: (i) minimizing fuel cost and (ii) minimizing pollutant emission. The bi-objective problem is converted into a single objective one by price penalty factor. The proposed method, denoted as QPSO-DM, combines the QPSO algorithm with differential mutation operation to enhance the global search ability. In this study, heuristic strategies are proposed to handle the equality constraints especially water dynamic balance constraints and active power balance constraints. A feasibility-based selection technique is also employed to meet the reservoir storage volumes constraints. To show the efficiency of the proposed method, different case studies are carried out and QPSO-DM is compared with the differential evolution (DE), the particle swarm optimization (PSO) with same heuristic strategies in terms of the solution quality, robustness and convergence property. The simulation results show that the proposed method is capable of yielding higher-quality solutions stably and efficiently in the short-term hydrothermal scheduling than any other tested optimization algorithms.

  19. A noninvasive method for measuring the velocity of diffuse hydrothermal flow by tracking moving refractive index anomalies

    Science.gov (United States)

    Mittelstaedt, Eric; Davaille, Anne; van Keken, Peter E.; Gracias, Nuno; Escartin, Javier

    2010-10-01

    Diffuse flow velocimetry (DFV) is introduced as a new, noninvasive, optical technique for measuring the velocity of diffuse hydrothermal flow. The technique uses images of a motionless, random medium (e.g., rocks) obtained through the lens of a moving refraction index anomaly (e.g., a hot upwelling). The method works in two stages. First, the changes in apparent background deformation are calculated using particle image velocimetry (PIV). The deformation vectors are determined by a cross correlation of pixel intensities across consecutive images. Second, the 2-D velocity field is calculated by cross correlating the deformation vectors between consecutive PIV calculations. The accuracy of the method is tested with laboratory and numerical experiments of a laminar, axisymmetric plume in fluids with both constant and temperature-dependent viscosity. Results show that average RMS errors are ˜5%-7% and are most accurate in regions of pervasive apparent background deformation which is commonly encountered in regions of diffuse hydrothermal flow. The method is applied to a 25 s video sequence of diffuse flow from a small fracture captured during the Bathyluck'09 cruise to the Lucky Strike hydrothermal field (September 2009). The velocities of the ˜10°C-15°C effluent reach ˜5.5 cm/s, in strong agreement with previous measurements of diffuse flow. DFV is found to be most accurate for approximately 2-D flows where background objects have a small spatial scale, such as sand or gravel.

  20. Synthesis and characterization of nanosized ceria powders by microwave-hydrothermal method

    International Nuclear Information System (INIS)

    Bonamartini Corradi, A.; Bondioli, F.; Ferrari, A.M.; Manfredini, T.

    2006-01-01

    Nanocrystalline ceria powders (CeO 2 ) have been prepared by adding NaOH to a cerium ammonium nitrate aqueous solution under microwave-hydrothermal conditions. In particular the effect of the synthesis conditions (time, pressure and concentration of both the precursor and the precipitant agent solutions) on the physical properties of the crystals have been evaluated. Microwave-hydrothermal treatment of 5 min at 13.4 atm allows to obtain almost crystallized powders (amorphous phase 4%) as underlined by Rietveld-reference intensity ratio (RIR) results

  1. Microstructure, morphology and magnetic properties of Ni nanoparticles synthesized by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Bouremana, A. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria); Guittoum, A., E-mail: aguittoum@gmail.com [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Hemmous, M. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Martínez-Blanco, D. [SCTs, University of Oviedo, EPM, 33600 Mieres (Spain); Gorria, Pedro [Department of Physics & IUTA, EPI, University of Oviedo, 33203 Gijón (Spain); Blanco, J.A. [Department of Physics, University of Oviedo, Calvo Sotelo St., 33007 Oviedo (Spain); Benrekaa, N. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria)

    2015-06-15

    Powder samples containing high purity nickel nanoparticles (NPs) were prepared by hydrothermal method from Ni(II) chloride hexahydrate (NiCl{sub 2}·6H{sub 2}O) under the presence of sodium hydroxide (NaOH) with different concentrations between 5 and 25 mol/L. The synthesis of the NPs occurs through chemical reduction at relatively low temperature (140 °C). The Ni NPs have a face-centred cubic (fcc) crystal structure with a lattice parameter value close to that of pure Ni (a = 3.52 Å). The average crystallite size determined from x-ray diffraction is around 20 nm, except for the sample synthesized under the highest NaOH concentration (25 mol/L), which has the largest average size (>30 nm). The powder morphology at the sub-micrometre length scale looks like agglomerates of Ni-NPs that drastically changes their shape depending on the NaOH concentration, from flower (5 mol/L) to a dendritic-like (25 mol/L). All the samples are ferromagnetic at room temperature with saturation magnetization values between 50 and 52emu/g, and a coercive field that increases with the NaOH concentration from around 135 (5 mol/L) up to 180Oe (25 mol/L). - Highlights: • Pure Nickel nanoparticles have been synthesized by a chemical reaction process. • Different morphologies were observed with the change of NaOH concentration. • The coercive field increases with increasing the NaOH concentration and depends on the shape of nanoparticles.

  2. TiO{sub 2}/N-graphene nanocomposite via a facile in-situ hydrothermal sol–gel strategy for visible light photodegradation of eosin Y

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yingliang; Pei, Fuyun, E-mail: xusg@zzu.edu.cn; Lu, Ruijuan; Xu, Shengang; Cao, Shaokui, E-mail: caoshaokui@zzu.edu.cn

    2014-12-15

    Highlights: • TiO{sub 2}/N-graphene is synthesized via in-situ hydrothermal sol–gel strategy. • TiO{sub 2} nanoparticles are chemically anchored on N-graphene nanosheets. • The band gap of TiO{sub 2}/N-graphene is red-shifted from neat TiO{sub 2} nanoparticles. • 5-NGT nanocomposite has the best visible light photodegradation performance. - Abstract: TiO{sub 2}/N-graphene nanocomposites are synthesized via a facile in-situ hydrothermal sol–gel strategy in order to improve the photocatalytic efficiency for pollutant photodegradation under visible light irradiation. The as-prepared nanocomposites are respectively characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and UV–vis diffuse reflectance spectroscopy. Results indicated that neat TiO{sub 2} nanoparticles have an average diameter about 6.70 nm while TiO{sub 2} nanoparticles in TiO{sub 2}/N-graphene nanocomposites synthesized through in-situ hydrothermal sol–gel strategy bear an average diameter of ∼1 nm and are anchored on N-graphene nanosheets via chemical bonding. Both neat TiO{sub 2} nanoparticles and chemically anchored TiO{sub 2} nanoparticles in TiO{sub 2}/N-graphene nanocomposites take on the crystal type of anatase. The band gap of TiO{sub 2}/N-graphene nanocomposites is red-shifted compared with neat TiO{sub 2} nanoparticles. The evaluation of photodegradation performance under visible light irradiation suggested that the nanocomposite with 5 wt% N-graphene content has the best visible light photodegradation performance.

  3. In-situ growth of ZnO nanowire arrays on the sensing electrode via a facile hydrothermal route for high-performance NO2 sensor

    Science.gov (United States)

    Chen, Xiangxiang; Shen, Yanbai; Zhang, Wei; Zhang, Jin; Wei, Dezhou; Lu, Rui; Zhu, Lijia; Li, Hansen; Shen, Yansong

    2018-03-01

    ZnO nanowire (ZNW) arrays were in-situ grown on the sensing electrode via a facile hydrothermal route for NO2 sensing application. ZNW arrays were prepared by a seed layer deposition on the surface of the sensing electrode using a dipping process in a Zn(CH3COO)2·2H2O ethanol solution followed by a seed growth using a hydrothermal route in the Zn(NO3)2·6H2O-HMTA (C6H12N4) system. The microstructural characterizations of the ZNW arrays by means of XRD, FESEM, TEM, FTIR and XPS showed that ZnO nanowires with the diameters of 80-90 nm and the lengths of 0.6-1 μm had a single crystal hexagonal wurtzite structure. Gas sensing properties demonstrated the response of the sensor based on the ZNW arrays was linearly proportional to the NO2 concentration in the range of 1-30 ppm with good reproducibility and selectivity. The maximum sensor response to NO2 was obtained at an operating temperature of 250 °C. The response and recovery times reduced rapidly with increasing the operating temperature. The growth mechanism and sensing mechanism of the ZNW arrays were discussed in accordance with the deposition of the seed layer and the modulation of the depletion layer, respectively.

  4. Facile Br{sup -} assisted hydrothermal synthesis of Bi{sub 2}MoO{sub 6} nanoplates with enhanced visible-light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Peng [Yangtze Normal University, Chongqing Key Laboratory of Inorganic Special Functional Materials, Chongqing (China); Yangtze Normal University, College of Chemistry and Chemical Engineering, Chongqing (China); Teng, Xiaoxu; Liu, Dongsheng; Fu, Liang; Xie, Hualin [Yangtze Normal University, College of Chemistry and Chemical Engineering, Chongqing (China); Zhang, Guoqing [Yangtze Normal University, Chongqing Key Laboratory of Inorganic Special Functional Materials, Chongqing (China); Ding, Shimin [Yangtze Normal University, Collaborative Innovation Center for Green Development in Wuling Mountain Areas, Chongqing (China)

    2017-10-15

    Bi{sub 2}MoO{sub 6} nanoplates have been controllably synthesized via a facile hydrothermal process with the assistance of Br{sup -} containing surfactant cetyltrimethylammonium bromide (CTAB) or KBr. A remarkable enhancement in the visible-light-driven photocatalytic degradation of Rhodamine B was observed. It was found that reaction temperature and surfactant play crucial roles in the formation and properties of the Bi{sub 2}MoO{sub 6} nanoplates. The best results as photocatalyst were obtained with the sample hydrothermally synthesized at 150 C with the assistance of CTAB. The improved photocatalytic performance could be ascribed to the {001}-oriented nanostructure of the Bi{sub 2}MoO{sub 6} nanoplates. KBr-templated Bi{sub 2}MoO{sub 6} nanoplates also showed better photocatalytic efficiency compared with that of flower-like Bi{sub 2}MoO{sub 6} but inferior to that of CTAB-templated Bi{sub 2}MoO{sub 6} nanoplates. (orig.)

  5. Influence of preparation methods of microwave, sol-gel, and hydrothermal on structural and optical properties of lanthania nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Goharshadi, Elaheh K.; Mahvelati, Tahereh; Yazdanbakhsh, Mohammad [Ferdowsi Univ., Mashhad (Iran, Islamic Republic of). Dept. of Chemistry

    2016-01-15

    In this work, the nearly pure hexagonal phase of lanthania nanoparticles (NPs) was successfully synthesized using three methods: microwave, sol-gel, and hydrothermal. The samples were characterized using nine techniques including powder X-ray powder diffraction, thermogravimetry, transmission electron microscopy, scanning electron microscopy, field emission microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, far infrared spectroscopy, and ultraviolet-visible absorption spectroscopy. This study showed that the method of synthesizing lanthania NPs can affect the size, which in turn has impact on structural, morphological, and optical properties.

  6. A green and facile hydrothermal approach for the synthesis of high-quality semi-conducting Sb{sub 2}S{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Meng; Gong, Yongshuai; Li, Zhilin; Dou, Meiling, E-mail: douml@mail.buct.edu.cn; Wang, Feng, E-mail: wangf@mail.buct.edu.cn

    2016-11-30

    Highlights: • A green and facile hydrothermal approach for Sb{sub 2}S{sub 3} films was developed. • The film possessed a relatively ideal S/Sb atomic ratio and a compact surface. • The grain size of Sb{sub 2}S{sub 3} was increased by high temperature annealing. • The film annealed at 450 °C showed the improved optical and electrical performance. - Abstract: High-quality semi-conducting antimony sulfide (Sb{sub 2}S{sub 3}) thin films were directly deposited on the indium tin oxide (ITO) substrates by a green and facile one-step approach based on a hydrothermal reaction and post-annealing process without any assistance of complexing agents. The obtained Sb{sub 2}S{sub 3} films possessed a relatively ideal S/Sb atomic ratio and a compact and continuous surface as the grain size of Sb{sub 2}S{sub 3} was increased by high temperature annealing. The Sb{sub 2}S{sub 3} film annealed at 450 °C exhibited the improved optical and electrical performances, with a narrow band gap of 1.63 eV, an electrical resistivity of 1.3 × 10{sup 4} Ω cm, a carrier concentration of 7.3 × 10{sup 13} cm{sup −3} and a carrier mobility of 6.4 cm{sup 2} V{sup −1} s{sup −1}. This environmentally friendly synthetic route is promising for the preparation of high-quality Sb{sub 2}S{sub 3} films to be used as absorber layer materials for high-performance solar cells.

  7. Facile hydrothermal synthesis of polyhedral Fe3O4 nanocrystals, influencing factors and application in the electrochemical detection of H2O2

    International Nuclear Information System (INIS)

    Yuan Kefeng; Ni Yonghong; Zhang Li

    2012-01-01

    Highlights: ► Fe 3 O 4 polyhedra had been successfully synthesized by a facile hydrothermal technology. ► The as-obtained product exhibited the room-temperature ferrimagnetic property. ► The final product could be prepared into an electrochemical sensor for the detection of H 2 O 2 . - Abstract: Polyhedral Fe 3 O 4 nanocrystals have been successfully synthesized by a facile hydrothermal technique, employing FeSO 4 ·7H 2 O, N 2 H 4 and NH 3 ·H 2 O as the reactants without the assistance of any surfactant. The phase of the as-obtained Fe 3 O 4 was characterized by X-ray powder diffraction (XRD) and further proved by Rietveld refinement of XRD data. Energy dispersive spectrometry (EDS) and scanning electron microscopy (SEM) were used for the composition and morphology analyses of the final product. Some factors influencing the formation of polyhedral Fe 3 O 4 nanocrystals were systematically investigated, including the reaction temperature and time, and the original volume ratio of NH 3 ·H 2 O/N 2 H 4 ·H 2 O. It was found that the as-prepared Fe 3 O 4 polyhedra exhibited a good electrochemical property in 0.1 M phosphate buffer solution (PBS) with pH 7.0 and could be prepared into an electrochemical sensor for the detection of H 2 O 2 . The linear response range of the sensor was 10.0 × 10 −6 to 140.0 × 10 −6 M and a sensitivity was 11.05 μA/mM. Furthermore, the room-temperature magnetic property of the product was also investigated.

  8. Characterization of hydroxyapatite coatings deposited by hydrothermal electrochemical method on NaOH immersed Ti6Al4V

    International Nuclear Information System (INIS)

    He, Daihua; Liu, Ping; Liu, Xinkuan; Ma, Fengcang; Chen, Xiaohong; Li, Wei; Du, Jiandi; Wang, Pu; Zhao, Jun

    2016-01-01

    The hydrothermal electrochemical method was used to deposit hydroxyapatite coating on Ti6Al4V. In order to improve the bonding strength between the coating and substrate, the substrates were modified by 8 M NaOH solution before the deposition. The effects of immersing time on the substrate, on the hydroxyapatite coating, and on the bonding strength were studied. X-Ray Diffraction, Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy and Drop Shape Analysis Method were applied. And the crystallinity of hydroxyapatite coating was calculated. The results show that immersing treatment effects the phase compositions, the microstructure and the wettability of the substrate surface. A porous, three-dimensional network structure is formed on the Ti6Al4V surface through the NaOH immersion. The pore size and depth increase with the increase of immersing time from 12 to 48 h. The surface microstructure of Ti6Al4V with 60 h′ immersion time was different from the others. The modification treatment can improve the bonding strength between hydroxyapatite coating and the substrate obviously. The value of the bonding strength with the substrate immersed for 48 h is larger than those of the others. A bone-like apatite layer forms on the coating after 3 days of soaking in SBF, implying with good bioactivity of the hydroxyapatite coatings deposited by the method. The surface characteristics of the sample immersed with 48 h are more conductive to the deposition of hydroxyapatite and to the improvement of the bonding strength. The formation mechanism of hydroxyapatite coating deposited by hydrothermal electrochemical method was discussed. - Highlights: • Immerse Ti6Al4V alloy with NaOH solution for different immersing time. • We deposit hydroxyapatite coating by hydrothermal electrochemical method. • We examine changes of composition, microstructure, bonding strength and bioactivity of the hydroxyapatite coating. • 48 h is the optimal immersing time. • We

  9. Synthesis and characterization of Ni-CeO2 catalysts by the hydrothermal method

    International Nuclear Information System (INIS)

    Lazcano O, I.

    2013-01-01

    At the present time the necessity exists to reduce the level of atmospheric pollutants, because these are the main originators of such problems as: the greenhouse effect, acid rain, global heating, among others and that are affecting the human being seriously. In this context, is necessary to look for new solutions that contribute to the improvement of the problems without appealing to limitations in the energy production, because this would imply a non only delay in the economic development, but also in the cultural, technological and of research in our country. An alternative for the energy solution is the use of renewable fuels, because they will decrease the production costs with the time, as well as to diminish the dependence of the fossil fuels, contributing this way to the improvement of the environment quality. The use of the hydrogen as an alternating fuel to the petroleum, is intends as energy solution. The objective of the present work is to develop Ni-CeO 2 catalysts through the hydrothermal method for the hydrogen production starting from the partial oxidation reaction of methanol for the clean fuel generation that does not produce polluting emissions to the environment. As well as, to determine the importance of the metallic load in the catalytic activity for which catalysts to 1 and 2% in weight of Ni were prepared. To achieve these objective different techniques were used to characterize the prepared catalysts, as: Temperature Programmed Reduction to evidence the metal-support interaction, Scanning Electron Microscopy (Sem) to determine the morphology of the catalysts, Surface Area (Bet) with respect to the adsorption-desorption of N 2 and X-Rays Diffraction (XRD) to know the crystalline structure of the catalysts. Also the catalytic properties (activity and selectivity) were studied under the reaction: CH 3 OH + 1/2 O 2 obtaining as products to the CO 2 + 2H 2 , with the help of the multi-tasks equipment Rig-100 that operated to temperatures among

  10. Large Marks-decahedral Pd nanoparticles synthesized by a modified hydrothermal method using a homogeneous reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haiqiang; Qi, Weihong, E-mail: qiwh216@csu.edu.cn; Ji, Wenhai; Wang, Tianran; Peng, Hongcheng; Wang, Qi; Jia, Yanlin; He, Jieting [Central South University, School of Materials Science and Engineering (China)

    2017-05-15

    Fivefold symmetry appears only in small particles and quasicrystals because internal stress in the particles increases with the particle size. However, a typical Marks decahedron with five re-entrant grooves located at the ends of the twin boundaries can further reduce the strain energy. During hydrothermal synthesis, it is difficult to stir the reaction solution contained in a digestion high-pressure tank because of the relatively small size and high-temperature and high-pressure sealed environment. In this work, we optimized a hydrothermal reaction system by replacing the conventional drying oven with a homogeneous reactor to shift the original static reaction solution into a full mixing state. Large Marks-decahedral Pd nanoparticles (~90 nm) have been successfully synthesized in the optimized hydrothermal synthesis system. Additionally, in the products, round Marks-decahedral Pd particles were also found for the first time. While it remains a challenge to understand the growth mechanism of the fivefold twinned structure, we proposed a plausible growth-mediated mechanism for Marks-decahedral Pd nanoparticles based on observations of the synthesis process.

  11. Large Marks-decahedral Pd nanoparticles synthesized by a modified hydrothermal method using a homogeneous reactor

    International Nuclear Information System (INIS)

    Zhao, Haiqiang; Qi, Weihong; Ji, Wenhai; Wang, Tianran; Peng, Hongcheng; Wang, Qi; Jia, Yanlin; He, Jieting

    2017-01-01

    Fivefold symmetry appears only in small particles and quasicrystals because internal stress in the particles increases with the particle size. However, a typical Marks decahedron with five re-entrant grooves located at the ends of the twin boundaries can further reduce the strain energy. During hydrothermal synthesis, it is difficult to stir the reaction solution contained in a digestion high-pressure tank because of the relatively small size and high-temperature and high-pressure sealed environment. In this work, we optimized a hydrothermal reaction system by replacing the conventional drying oven with a homogeneous reactor to shift the original static reaction solution into a full mixing state. Large Marks-decahedral Pd nanoparticles (~90 nm) have been successfully synthesized in the optimized hydrothermal synthesis system. Additionally, in the products, round Marks-decahedral Pd particles were also found for the first time. While it remains a challenge to understand the growth mechanism of the fivefold twinned structure, we proposed a plausible growth-mediated mechanism for Marks-decahedral Pd nanoparticles based on observations of the synthesis process.

  12. Structural and dielectric properties of barium strontium titanate produced by high temperature hydrothermal method

    International Nuclear Information System (INIS)

    Razak, K.A.; Asadov, A.; Yoo, J.; Haemmerle, E.; Gao, W.

    2008-01-01

    The preparation procedure, structural and dielectric properties of hydrothermally derived Ba x Sr 1-x TiO 3 (BST) were studied. BST with initial Ba compositions of 75, 80, 85 and 90 mol.% were prepared by a high temperature hydrothermal synthesis. The obtained powders were pressed into pellet, cold isostatically pressed and sintered at 1200 deg. C for 3 hours. The phase compositions and lattice parameters of the as prepared powders and sintered samples were analysed using X-ray diffractometry. A fitting software was used to analyse the XRD spectra to separate different phases. It was found that BST powder produced by the high temperature hydrothermal possessed a two-phase structure. This structure became more homogeneous during sintering due to interdiffusion but a small amount of minor phase can still be traced. Samples underwent an abnormal grain growth, whereby some grains grow faster than the other due to the presence of two-phase structure. The grain size increased with increasing Ba amount. Dielectric constant and polarisation increased with increasing Ba content but it was also affected by the electronic state and grain size of the compositions

  13. In situ controlled synthesis of various TiO2 nanostructured materials via a facile hydrothermal route

    International Nuclear Information System (INIS)

    Wang Hai; Liu Yong; Zhong Minyi; Xu Hongmei; Huang Hong; Shen Hui

    2011-01-01

    Various TiO 2 nanomaterials, such as nanosheets, nanoflowers, and nanowires were directly self assembled on titanium substrate on a large scale under hydrothermal conditions. The morphology of the formed TiO 2 nanomaterials could be easily tuned by varying the experimental parameters of temperature, reaction time, and the NaOH concentration. A possible formation mechanism was suggested on the basis of the shape evolution of TiO 2 nanostructures by SEM images in combination with XRD patterns of as-grown samples. The optical properties of TiO 2 nanosheets, nanoflowers, and nanowires were characterized by reflectance spectroscopy. The studies revealed that the absorption capability of visible light is obviously different for TiO 2 with different morphologies. Moreover, TiO 2 nanosheets exhibited better light trapping than TiO 2 nanoflowers and TiO 2 nanowires due to their unique nanostructure.

  14. Growth Mechanism of γ-MnS Nanorod-Arrays by Hydrothermal Method on Anodic Aluminum Oxide Template

    International Nuclear Information System (INIS)

    Huang, Jianming; Liu, Weifeng; Lv, Yong; Yao, Lianzeng

    2010-01-01

    Hydrothermal method is a general, low-cost and convenience method which was utilized for synthesis of nanomaterials. Our research group has reported that oriented MnS nanorods on anodic aluminum oxide template were synthesized under a hydrothermal condition and demonstrated the effect of precursor content on the morphology evolution of as-samples. In order to research the growth mechanism of the arrays, herein we synthesized MnS nanorod arrays by combination of anodic aluminum oxide template and hydrothermal method on different substrates. Through-hole anodic aluminum oxide templates were prepared using Al foil (99.999%) via a two-step anodization process as described in literature. To investigate the effect of different substrates on the morphology of the-products, different substrates including anodic aluminum oxide template (sample A), one-step anodization Al foil (sample B, which was prepared by first anodizing Al foil for 10h and then removing the alumina layer with the mixed acid (0.6 M H 3 PO 4 and 0.15 M H 2 CrO 4 ), where the foil still kept the close-packed concave nano-pits consistently with the nanopole of anodic aluminum oxide template), Al foil (sample C, dipped in HNO 3 solution and covered by a compact alumina layer), Si wafer (sample D) respectively were put into Teflon-lined stainless steel autoclaves of 20 mL capacity filled with 16 mL mixed solution consisting of 2 mol/L MnCl 4 and 2 mol/L thiourea. We kept the reaction at 150 .deg. C for 20 h. When reactions completed the products were washed three times with distilled water and absolute ethanol, respectively. Then the products were dried in an oven at 60 .deg. C

  15. Growth Mechanism of γ-MnS Nanorod-Arrays by Hydrothermal Method on Anodic Aluminum Oxide Template

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jianming; Liu, Weifeng; Lv, Yong; Yao, Lianzeng [Chinese Academy of Science, Hefei, Anhui (China)

    2010-09-15

    Hydrothermal method is a general, low-cost and convenience method which was utilized for synthesis of nanomaterials. Our research group has reported that oriented MnS nanorods on anodic aluminum oxide template were synthesized under a hydrothermal condition and demonstrated the effect of precursor content on the morphology evolution of as-samples. In order to research the growth mechanism of the arrays, herein we synthesized MnS nanorod arrays by combination of anodic aluminum oxide template and hydrothermal method on different substrates. Through-hole anodic aluminum oxide templates were prepared using Al foil (99.999%) via a two-step anodization process as described in literature. To investigate the effect of different substrates on the morphology of the-products, different substrates including anodic aluminum oxide template (sample A), one-step anodization Al foil (sample B, which was prepared by first anodizing Al foil for 10h and then removing the alumina layer with the mixed acid (0.6 M H{sub 3}PO{sub 4} and 0.15 M H{sub 2}CrO{sub 4}), where the foil still kept the close-packed concave nano-pits consistently with the nanopole of anodic aluminum oxide template), Al foil (sample C, dipped in HNO{sub 3} solution and covered by a compact alumina layer), Si wafer (sample D) respectively were put into Teflon-lined stainless steel autoclaves of 20 mL capacity filled with 16 mL mixed solution consisting of 2 mol/L MnCl{sub 4} and 2 mol/L thiourea. We kept the reaction at 150 .deg. C for 20 h. When reactions completed the products were washed three times with distilled water and absolute ethanol, respectively. Then the products were dried in an oven at 60 .deg. C.

  16. Immobilization of LiCl-Li 2 O pyroprocessing salt wastes in chlorosodalite using glass-bonded hydrothermal and salt-occlusion methods

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J.; Peterson, Jacob A.; Kroll, Jared O.; Frank, Steven M.

    2018-04-01

    In this study, salt occlusion and hydrothermal processes were used to make chlorosodalite through reaction with a high-LiCl salt simulating a waste stream following pyrochemical treatment of oxide-based used nuclear fuel. Some products were reacted with glass binders to increase chlorosodalite yield through alkali ion exchange and aide in densification. Hydrothermal processes included reaction of the salt simulant in an acid digestion vessel with either zeolite 4A or sodium aluminate and colloidal silica. Chlorosodalite yields in the crystalline products were nearly complete in the glass-bonded materials at values of 100 mass% for the salt-occlusion method, up to 99.0 mass% for the hydrothermal synthesis with zeolite 4A, and up to 96 mass% for the hydrothermal synthesis with sodium aluminate and colloidal silica. These results show promise for using chemically stable chlorosodalite to immobilize oxide reduction salt wastes.

  17. Immobilization of LiCl-Li2O pyroprocessing salt wastes in chlorosodalite using glass-bonded hydrothermal and salt-occlusion methods

    Science.gov (United States)

    Riley, Brian J.; Peterson, Jacob A.; Kroll, Jared O.; Frank, Steven M.

    2018-04-01

    In this study, hydrothermal and salt-occlusion processes were used to make chlorosodalite through reactions with a high-LiCl salt simulating a waste stream generated from pyrochemical treatment of oxide-based used nuclear fuel. Some products were reacted with glass binders to increase chlorosodalite yield through alkali ion exchange and to aid in densification. Hydrothermal processes included reaction of the salt simulant in an autoclave with either zeolite 4A or sodium aluminate and colloidal silica. Chlorosodalite yields in the crystalline products were nearly complete in the glass-bonded materials at values of 100 mass% for the salt-occlusion method, up to 99.0 mass% for the hydrothermal synthesis with zeolite 4A, and up to 96 mass% for the hydrothermal synthesis with sodium aluminate and colloidal silica. These results show promise for using chemically stable chlorosodalite to immobilize oxide reduction salt wastes.

  18. Structural and photoluminescence properties of aligned Sb-doped ZnO nanocolumns synthesized by the hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Fang Xuan [School of Science, Changchun University of Science and Technology, 7089-WeiXing Road, Changchun, 130022 (China); Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone Changchun, 130033 (China); Li Jinhua [School of Science, Changchun University of Science and Technology, 7089-WeiXing Road, Changchun, 130022 (China); Zhao Dongxu, E-mail: dxzhao2000@yahoo.com.c [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone Changchun, 130033 (China); Li Binghui; Zhang Zhenzhong; Shen Dezhen [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone Changchun, 130033 (China); Wang Xiaohua; Wei Zhipeng [School of Science, Changchun University of Science and Technology, 7089-WeiXing Road, Changchun, 130022 (China)

    2010-08-02

    Aligned Sb-doped ZnO nanocolumns were synthesized by a simple hydrothermal method. Based on the analyses of the X-ray diffraction and photoluminescence result, it could be confirmed that the Sb has successfully doped in the ZnO crystal lattices to form an accepter energy level. At 85 K, the recombination of the acceptor-bound exciton was predominant in PL spectrum, which was attributed to the transition of the (Sb{sub Zn}-2V{sub Zn}) complex bound exciton. The acceptor binding energy had been calculated to be 123 meV.

  19. Structural and photoluminescence properties of aligned Sb-doped ZnO nanocolumns synthesized by the hydrothermal method

    International Nuclear Information System (INIS)

    Fang Xuan; Li Jinhua; Zhao Dongxu; Li Binghui; Zhang Zhenzhong; Shen Dezhen; Wang Xiaohua; Wei Zhipeng

    2010-01-01

    Aligned Sb-doped ZnO nanocolumns were synthesized by a simple hydrothermal method. Based on the analyses of the X-ray diffraction and photoluminescence result, it could be confirmed that the Sb has successfully doped in the ZnO crystal lattices to form an accepter energy level. At 85 K, the recombination of the acceptor-bound exciton was predominant in PL spectrum, which was attributed to the transition of the (Sb Zn -2V Zn ) complex bound exciton. The acceptor binding energy had been calculated to be 123 meV.

  20. TEMPEST: A three-dimensional time-dependent computer program for hydrothermal analysis: Volume 1, Numerical methods and input instructions

    International Nuclear Information System (INIS)

    Trent, D.S.; Eyler, L.L.; Budden, M.J.

    1983-09-01

    This document describes the numerical methods, current capabilities, and the use of the TEMPEST (Version L, MOD 2) computer program. TEMPEST is a transient, three-dimensional, hydrothermal computer program that is designed to analyze a broad range of coupled fluid dynamic and heat transfer systems of particular interest to the Fast Breeder Reactor thermal-hydraulic design community. The full three-dimensional, time-dependent equations of motion, continuity, and heat transport are solved for either laminar or turbulent fluid flow, including heat diffusion and generation in both solid and liquid materials. 10 refs., 22 figs., 2 tabs

  1. Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis

    Directory of Open Access Journals (Sweden)

    Muhammad Faizan Shareef

    2017-10-01

    Full Text Available This paper presents the effect of a synthesis method for cobalt catalyst supported on hydrotalcite material for Fischer-Tropsch synthesis. The hydrotalcite supported cobalt (HT-Co catalysts were synthesized by co-precipitation and hydrothermal method. The prepared catalysts were characterized by using various techniques like BET (Brunauer–Emmett–Teller, SEM (Scanning Electron Microscopy, TGA (Thermal Gravimetric Analysis, XRD (X-ray diffraction spectroscopy, and FTIR (Fourier Transform Infrared Spectroscopy. Fixed bed micro reactor was used to test the catalytic activity of prepared catalysts. The catalytic testing results demonstrated the performance of hydrotalcite based cobalt catalyst in Fischer-Tropsch synthesis with high selectivity for liquid products. The effect of synthesis method on the activity and selectivity of catalyst was also discussed. Copyright © 2017 BCREC Group. All rights reserved Received: 3rd November 2016; Revised: 26th February 2017; Accepted: 9th March 2017; Available online: 27th October 2017; Published regularly: December 2017 How to Cite: Sharif, M.S., Arslan, M., Iqbal, N., Ahmad, N., Noor, T. (2017. Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 12(3: 357-363 (doi:10.9767/bcrec.12.3.762.357-363

  2. Effect of precursor concentration on the structural and optical properties of ZnO nanorods prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Lestari, Amie; Iwan, S.; Djuhana, Dede; Imawan, Cuk; Harmoko, Adhi; Fauzia, Vivi

    2016-01-01

    Zinc oxide (ZnO) nanorods has attractive properties for nanoscale optoelectronic applications, such as optical sensors, ultraviolet laser diodes, and photodetectors. ZnO nanorods, can be fabricated by simple and low cost chemical approach, such as hydrothermal method. In this method, the morphology, microstructure, optical and electrical properties of ZnO nanorods are highly determined by process parameters such as solvent, deposition time, deposition temperature as well as annealing condition. In this paper we report the fabrication of ZnO nanorods that were grown on transparent conducting indium tin oxide coated glass substrates. Initially, ZnO seed layers were deposited on heated substrates with temperature of 450 °C using ultrasonic spray pyrolysis method with frequency of 1.7 MHz and then grown by hydrothermal method with three different precursor concentrations, namely 0.02 M, 0.06 M, and 0.1 M. The surface morphology and structure were investigated by field emission scanning electron microscope (FESEM) and x-ray diffraction (XRD), while the optical properties were observed by photoluminescence (PL) and and UV VIS reflectance spectroscopy.

  3. Structural and electrical properties of TiO2/ZnO core–shell nanoparticles synthesized by hydrothermal method

    International Nuclear Information System (INIS)

    Vlazan, P.; Ursu, D.H.; Irina-Moisescu, C.; Miron, I.; Sfirloaga, P.; Rusu, E.

    2015-01-01

    TiO 2 /ZnO core–shell nanoparticles were successfully synthesized by hydrothermal method in two stages: first stage is the hydrothermal synthesis of ZnO nanoparticles and second stage the obtained ZnO nanoparticles are encapsulated in TiO 2 . The obtained ZnO, TiO 2 and TiO 2 /ZnO core–shell nanoparticles were investigated by means of X-ray diffraction, transmission electron microscopy, Brunauer, Emmett, Teller and resistance measurements. X-ray diffraction analysis revealed the presence of both, TiO 2 and ZnO phases in TiO 2 /ZnO core–shell nanoparticles. According to transmission electron microscopy images, ZnO nanoparticles have hexagonal shapes, TiO 2 nanoparticles have a spherical shape, and TiO 2 /ZnO core–shell nanoparticles present agglomerates and the shape of particles is not well defined. The activation energy of TiO 2 /ZnO core–shell nanoparticles was about 101 meV. - Graphical abstract: Display Omitted - Highlights: • TiO 2 /ZnO core–shell nanoparticles were synthesized by hydrothermal method. • TiO 2 /ZnO core–shell nanoparticles were investigated by means of XRD, TEM and BET. • Electrical properties of TiO 2 /ZnO core–shell nanoparticles were investigated. • The activation energy of TiO 2 /ZnO core–shell nanoparticles was about E a = 101 meV

  4. A facile approach to the elucidation of magnetic parameters of CuFe{sub 2}O{sub 4} nanoparticles synthesized by hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Kurian, Jessyamma [B.A.M. College, Thuruthicad, Mallappally, Kerala (India); Jacob Mathew, M., E-mail: jacob.chrisdale@gmail.com [S.B. College, Changanassery, Kerala (India)

    2017-04-15

    Pure pseudo cubic shaped copper ferrite nanoparticles with narrow size distribution in the range 6–17 nanometer are prepared by hydrothermal method under various synthesis conditions namely, hydrothermal temperature, heating time, and pH. The structural and morphological studies are carried out in detail using XRD and TEM analysis. The crystallite size and particle size are calculated from different characterization techniques. The distribution of cations among the tetrahedral and octahedral sites is determined from the XRD intensity calculation. Compositional features are determined from EDS analysis. Magnetic studies are carried out using VSM at room temperature and the important magnetic parameters are extracted from it. Contributions due to various types of magnetization to the total magnetization are determined from the theoretical fitting of the magnetization curve. Excellent fits are obtained for all samples prepared under various conditions. The ferromagnetic, superparamagnetic and paramagnetic contributions to the magnetization are determined from the analysis of fitted M-H curve. It is observed that the hydrothermal reaction time and temperature has little effect on the structural and magnetic parameters of the material. However, pH plays a crucial role in the physical properties of nanoparticles. Optimized synthesis conditions are identified for changing the soft ferrimagnetic nature of copper ferrite nanoparticles to superparamagnetic nature. - Highlights: • CuFe{sub 2}O{sub 4} particles of 6–17 nm size are produced by varying synthesis conditions. • Cubic single phase nano copper ferrite is obtained at a pH of 12. • Magnetic parameters calculated from theoretical fitting of M-H curves. • Dependence of the magnetic properties on Particle size and pH elucidated.

  5. Synthesis of magnetite octahedrons from iron powders through a mild hydrothermal method

    International Nuclear Information System (INIS)

    Mao Baodong; Kang Zhenhui; Wang Enbo; Lian Suoyuan; Gao Lei; Tian Chungui; Wang Chunlei

    2006-01-01

    Magnetite (Fe 3 O 4 ) octahedral particles were fabricated from iron powders through a simple one-step alkali-assisted hydrothermal process. The crystallinity, morphology, and structural features of the as-prepared magnetite particles were investigated using powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The values of saturation magnetization (M s ) and coercivity (H) of the magnetite octahedrons characterized on a vibrating sample magnetometer (VSM) are 89.81 emu/g and 70.6 Oe, respectively. The concentration of NaOH and the reaction temperature played a key role in the formation of the magnetite octahedrons

  6. An integrated lean-methods approach to hospital facilities redesign.

    Science.gov (United States)

    Nicholas, John

    2012-01-01

    Lean production methods for eliminating waste and improving processes in manufacturing are now being applied in healthcare. As the author shows, the methods are appropriate for redesigning hospital facilities. When used in an integrated manner and employing teams of mostly clinicians, the methods produce facility designs that are custom-fit to patient needs and caregiver work processes, and reduce operational costs. The author reviews lean methods and an approach for integrating them in the redesign of hospital facilities. A case example of the redesign of an emergency department shows the feasibility and benefits of the approach.

  7. Mesoporous 1D TiO_2 nanostructures obtained by the hydrothermal method

    International Nuclear Information System (INIS)

    Cabrera, Julieta; Vilchez, Ricardo; Alarcon, Hugo; Rodriguez, Juan; Lopez, Alcides

    2014-01-01

    Mesoporous one dimensional nanostructures (1D) such as nanotubes/nanorods of TiO_2 were synthesized by alkaline hydrothermal treatment of TiO_2 nanoparticles obtained by Sol Gel process (SG-TiO_2). The electronic microscopy images revealed the nanotubes formation of approximately 8 nm in diameter and more than around 400 nm long after hydrothermal treatment of 18 h and 24 h. These tube-like structures were maintained after acid treatment but after annealing at 400 °C during 2 hours these turn into rod-like structures of crystalline TiO_2 corresponding to anatase phase as revealed the diffraction patterns obtained by X-Ray Diffraction (XRD). The conversion of nanoparticles into nanotubes and afterward into rodlike shape was also confirmed by the variations in the BET surface area from 201, 269 and 97 m"2/g around, respectively. The adsorption-desorption isotherms also revealed hysteresis loop typical of mesoporous materials. These qualities are attractive to use these materials for the treatment of pollutants in water, for example. (author)

  8. Synthesis of zinc aluminate with high surface area by microwave hydrothermal method applied in the transesterification of soybean oil (biodiesel)

    International Nuclear Information System (INIS)

    Quirino, M.R.; Oliveira, M.J.C.; Keyson, D.; Lucena, G.L.; Oliveira, J.B.L.; Gama, L.

    2016-01-01

    Highlights: • ZnAl_2O_4 spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min. • The powders show high specific surface area. • ZAT_b15 showed activity of 52.22% for the conversion of soybean oil into biodiesel. - Abstract: Zinc aluminate is a material with high thermal stability and high mechanical strength that, owing to these properties, is used as a catalyst or support. In this work, zinc aluminate spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min at a low temperature (150 °C) without templates, using only Al(NO_3)_3·9H_2O, Zn(NO_3)_2·6H_2O, and urea as precursors and applied in the transesterification of soybean oil. X-ray diffraction analysis showed that ZnAl_2O_4 had a cubic structure without secondary phases. The nitrogen adsorption measurements (BET) revealed a high surface area (266.57 m"2 g"−"1) for the nanopowder synthesized in 15 min. This powder showed activity of 52.22% for the catalytic conversion of soybean oil into biodiesel by transesterification.

  9. Electronic structure and magnetic properties of FeWO{sub 4} nanocrystals synthesized by the microwave-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, M.A.P. [INCTMN-DQ-Universidade Federal de Sao Carlos, Sao Carlos, P.O. Box 676, 13565-905, SP (Brazil); Cavalcante, L.S., E-mail: laeciosc@bol.com.br [INCTMN-Universidade Estadual, Paulista, P.O. Box 355, 14801-907, Araraquara, SP (Brazil); Morilla-Santos, C.; Filho, P.N. Lisboa [MAv-Universidade Estadual, Paulista, P.O. Box 473, 17033-360, Bauru, SP (Brazil); Beltran, A.; Andres, J.; Gracia, L. [Department de Quimica Fisica i Analitica, Universitat Jaume I, E-12071 Castello (Spain); Longo, E. [INCTMN-DQ-Universidade Federal de Sao Carlos, Sao Carlos, P.O. Box 676, 13565-905, SP (Brazil); INCTMN-Universidade Estadual, Paulista, P.O. Box 355, 14801-907, Araraquara, SP (Brazil)

    2012-11-15

    This communication reports that FeWO{sub 4} nanocrystals were successfully synthesized by the microwave-hydrothermal method at 443 K for 1 h. The structure and shape of these nanocrystals were characterized by X-ray diffraction, Rietveld refinement, and transmission electron microscopy. The experimental results and first principles calculations were combined to explain the electronic structure and magnetic properties. Experimental data were obtained by magnetization measurements for different applied magnetic fields. Theoretical calculations revealed that magnetic properties of FeWO{sub 4} nanocrystals can be assigned to two magnetic orderings with parallel or antiparallel spins in adjacent chains. These factors are crucial to understanding of competition between ferro- and antiferromagnetic behavior. Highlights: Black-Right-Pointing-Pointer Monophasic FeWO{sub 4} nanocrystals were synthesized by the microwave-hydrothermal method. Black-Right-Pointing-Pointer Rietveld refinement and clusters model for monoclinic structure Black-Right-Pointing-Pointer Magnetic properties of FeWO{sub 4} nanocrystals at different temperatures.

  10. Synthesis of zinc aluminate with high surface area by microwave hydrothermal method applied in the transesterification of soybean oil (biodiesel)

    Energy Technology Data Exchange (ETDEWEB)

    Quirino, M.R. [Chemistry Laboratory of Federal University of Paraiba (LABQUIM), Campus III, 58200-000 Bananeiras, PB (Brazil); Oliveira, M.J.C. [Academic Unit of Materials Engineering, UFCG, Campina Grande Campus I, 58429-900 Campina Grande, PB (Brazil); Keyson, D. [Laboratory of study in Science, DME, Federal University of Paraíba, Campus I, 58051-900 João Pessoa, PB (Brazil); Lucena, G.L., E-mail: guilherme_leo1@yahoo.com.br [Chemistry Laboratory of Federal University of Paraiba (LABQUIM), Campus III, 58200-000 Bananeiras, PB (Brazil); Oliveira, J.B.L. [Federal University of Rio Grande do Norte, UFRN, Campus I, 59078-970 Natal, RN (Brazil); Gama, L. [Academic Unit of Materials Engineering, UFCG, Campina Grande Campus I, 58429-900 Campina Grande, PB (Brazil)

    2016-02-15

    Highlights: • ZnAl{sub 2}O{sub 4} spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min. • The powders show high specific surface area. • ZAT{sub b}15 showed activity of 52.22% for the conversion of soybean oil into biodiesel. - Abstract: Zinc aluminate is a material with high thermal stability and high mechanical strength that, owing to these properties, is used as a catalyst or support. In this work, zinc aluminate spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min at a low temperature (150 °C) without templates, using only Al(NO{sub 3}){sub 3}·9H{sub 2}O, Zn(NO{sub 3}){sub 2}·6H{sub 2}O, and urea as precursors and applied in the transesterification of soybean oil. X-ray diffraction analysis showed that ZnAl{sub 2}O{sub 4} had a cubic structure without secondary phases. The nitrogen adsorption measurements (BET) revealed a high surface area (266.57 m{sup 2} g{sup −1}) for the nanopowder synthesized in 15 min. This powder showed activity of 52.22% for the catalytic conversion of soybean oil into biodiesel by transesterification.

  11. Luminescent nanocrystals in the rare-earth niobate–zirconia system formed via hydrothermal method

    International Nuclear Information System (INIS)

    Hirano, Masanori; Dozono, Hayato

    2013-01-01

    Luminescent nanocrystals based on the rare-earth niobates (Ln 3 NbO 7 , Ln=Y, Eu) and zirconia (ZrO 2 ) that were composed of 50 mol% Ln 3 NbO 7 and 50 mol% ZrO 2 , were hydrothermally formed as cubic phase under weakly basic conditions at 240 °C. The lattice parameter of the as-prepared nanoparticles corresponding to the composition of Y 3−x Eu x NbO 7 –4ZrO 2 that was estimated as a single phase of cubic gradually increased as the content of europium x increased. The existence of small absorbance peaks at 395 and 466 nm corresponding to the Eu 3+7 F 0 → 5 L 6 , and 7 F 0 → 5 D 2 excitation transition, respectively, was clearly observed in the diffuse reflectance spectra of the as-prepared samples containing europium. The optical band gap of the as-prepared samples was in the range from 3.5 to 3.7 eV. The photoluminescence spectra of the as-prepared nanocrystals containing europium showed orange and red luminescences with main peaks at 590 and 610 nm, corresponding to 5 D 0 → 7 F 1 and 5 D 0 → 7 F 2 transitions of Eu 3+ , respectively, under excitation at 395 nm Xe lamp. The emission intensity corresponding to 5 D 0 → 7 F 2 transition increased as heat-treatment temperature rose from 800 to 1200 °C. - Graphical abstract: This graphical abstract shows the excitation and emission spectra and a transmission electron microscopy image of nanocrystals (with composition based on the rare-earth niobates (Ln 3 NbO 7 , Ln=Y, Eu) and zirconia (ZrO 2 ) that were composed of 50 mol% Ln 3 NbO 7 and 50 mol% ZrO 2 ) formed via hydrothermal route. Display Omitted - Highlights: • Nanocrystals composed of 50 mol% Y 3−x Eu x NbO 7 and 50 mol% ZrO 2 was directly formed. • The nanocrystals were hydrothermally formed under weakly basic conditions at 240 °C. • The Y 3 NbO 7 showed an UV-blue and broad-band emission under excitation at 240 nm. • The emission is originated from the niobate octahedral group [NbO 6 ] 7− . • The nanocrystals showed orange and

  12. Effects of hydrothermal annealing on characteristics of CuInS{sub 2} thin films by SILAR method

    Energy Technology Data Exchange (ETDEWEB)

    Shi Yong, E-mail: sys-99@163.com [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Sciences and Technology, Dalian University of Technology, Dalian 116024 (China); Xue Fanghong [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Sciences and Technology, Dalian University of Technology, Dalian 116024 (China); Li Chunyan [School of Materials, Dalian University of Technology, Dalian 116024 (China); Zhao Qidong; Qu Zhenping; Li Xinyong [Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Sciences and Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-07-15

    CuInS{sub 2} thin films have been deposited by successive ionic layer absorption and reaction (SILAR) method, then annealed in a Na{sub 2}S solution (denoted as hydrothermal annealing) at 200 Degree-Sign C for different time. The effect of hydrothermal annealing on the properties of the films was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and optical absorption spectroscopy. The XRD, TEM and SEM results indicate that well-crystallized CuInS{sub 2} films could be obtained after annealing in 0.1 mol/L Na{sub 2}S solution for 1.5 h. The annealed CuInS{sub 2} films were slightly S-rich and the direct band gap varied from 1.32 to 1.58 eV as the annealing time increased from 0.5 h to 2 h.

  13. Methods for sulfate removal in liquid-phase catalytic hydrothermal gasification of biomass

    Science.gov (United States)

    Elliott, Douglas C; Oyler, James

    2013-12-17

    Processing of wet biomass feedstock by liquid-phase catalytic hydrothermal gasification must address catalyst fouling and poisoning. One solution can involve heating the wet biomass with a heating unit to a pre-treatment temperature sufficient for organic constituents in the feedstock to decompose, for precipitates of inorganic wastes to form, for preheating the wet feedstock in preparation for subsequent removal of soluble sulfate contaminants, or combinations thereof. Processing further includes reacting the soluble sulfate contaminants with cations present in the feedstock material to yield a sulfate-containing precipitate and separating the inorganic precipitates and/or the sulfate-containing precipitates out of the wet feedstock. Having removed much of the inorganic wastes and the sulfate contaminants that can cause poisoning and fouling, the wet biomass feedstock can be exposed to the heterogenous catalyst for gasification.

  14. Analyze the Air Force Methods for Facility Sustainment and Restoration

    National Research Council Canada - National Science Library

    Cole, Ronald

    2003-01-01

    ...) and try to capitalize on industry standard practices to improve the AF methods. Industry has conducted extensive research devoted to the development of predictive models to estimate facility maintenance or sustainment requirements...

  15. One-step facile hydrothermal synthesis of Fe2O3@LiCoO2 composite as excellent supercapacitor electrode materials

    Science.gov (United States)

    Gopi, Chandu V. V. Muralee; Somasekha, A.; Reddy, Araveeti Eswar; Kim, Soo-Kyoung; Kim, Hee-Je

    2018-03-01

    Herein, for the first time, we demonstrate the fabrication of Fe2O3@LiCoO2 hybrid nanostructures on Ni foam substrate by facile one-step hydrothermal technique. Morphological studies reveal that aggregated Fe2O3 nanoflakes anchored on the surface of sphere-like LiCoO2 nanoflakes. Electrochemical studies are used to examine the performance of the supercapacitor electrodes. The composite Fe2O3@LiCoO2 electrode exhibited excellent electrochemical performance than Fe2O3 and LiCoO2 electrodes, such as a low charge transfer resistance, a high specific capacitance of 489 F g-1 at 5 mA cm-2 and an enhanced capacity retention of 108% over 3000 cycles at 15 mA cm-2. The composite Fe2O3@LiCoO2 holds great promise for electrochemical applications due to well-defined hierarchical morphology, synergetic effect of Fe2O3 and LiCoO2, enhanced electrical conductivity, efficient electrolyte penetration and fast electron transfer.

  16. Nuclide separation by hydrothermal treatment and ion exchange: a highly effective method for treatment of liquid effluents - 59217

    International Nuclear Information System (INIS)

    Braehler, Georg; Rieck, Ronald; Avramenko, V.A.; Sergienko, V.I.; Antonov, E.A.

    2012-01-01

    Liquid low level radioactive effluents, when solidified in e.g. cement matrix, contribute to a significant extent to the waste amount to be disposed of in final repositories. Accordingly, since many years scientists and engineers investigate processes to remove the radioactive nuclides selectively from the effluents, to split the raw solution into two separate fractions: a large fraction with activity concentrations below the limits for free release; and a small fraction, containing the activity in concentrated form on e. g. ion exchanger materials (ion exchange has proven to be the most promising method for such 'nuclide separation'). The challenge to be taken up is: When (and this is most often the case) the effluent contains organic materials and complexing agents, the formation of e. g. the 60-Co-EDTA complex prohibits its fixation to the ion exchangers. Accordingly the complexing agent needs to be removed or destroyed. The Institute for Chemistry of the Russian Academy of Sciences has applied the method of hydrothermal treatment (at elevated temperature and pressure, 200 deg. C, 200 bar), supported by Hydrogen Peroxide oxidation, to allow virtually complete removal of radioactive nuclides on inorganic ion exchangers. Pilot plants have been operated successfully in Russian power stations, and an operational plant has been designed. The method is being extended for an interesting and promising application: spent organic ion exchange resins, loaded up to the medium activity level, represent a serious disposal problem. With the hydrothermal process, in a process cycle, the activity can be stripped from the resins, the organic content is destroyed, and the activity is fixed on an inorganic absorber, well suited for final disposal. (authors)

  17. A novel hydrothermal method to convert incineration ash into pollucite for the immobilization of a simulant radioactive cesium

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Zhenzi, E-mail: zzjing@tongji.edu.cn [Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, Tongji University, 4800 Cao’an Road, Shanghai 201804 (China); Hao, Wenbo; He, Xiaojun; Fan, Junjie; Zhang, Yi; Miao, Jiajun [Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, Tongji University, 4800 Cao’an Road, Shanghai 201804 (China); Jin, Fangming [School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

    2016-04-05

    Highlights: • Incineration ash could be converted hydrothermally to pollucite to immobilize Cs. • Pollucite could be synthesized readily with a wide range of Cs/Si ratios. • With Ca(OH){sub 2} added, a tough pollucite could be used to solidify Cs-polluted RHA. • Leaching results showed that the amount of Cs leached from specimen was very low. - Abstract: The Fukushima nuclear accident in Japan on March 11, 2011 produced huge amounts of Cs-polluted incineration ashes; conventional solidification methods seem unsuitable for the treatment of large amounts of Cs-polluted ashes. A novel hydrothermal method was developed to directly convert Cs-polluted incineration ash (rice husk ash) into pollucite to immobilize Cs in its crystal structure in situ. Results revealed that pollucite could be synthesized readily over a wide range of added Cs (Cs/Si = 0.2–0.6); the addition of more Cs (Cs/Si ≥ 0.5) caused the formation of a small amount of cesium aluminosilicate (CsAlSiO{sub 4}), which exhibits poor immobilization behavior for Cs. Pollucite could be formed even for a short curing time (1 h) or at a low curing temperature (150 °C). However, a high curing temperature or a long curing time favored the formation of a pure pollucite. With the added calcium hydroxide, a tough specimen with a flexural strength of approximately 22 MPa could be obtained, which suggested that this technology may be applied directly to the solidification of Cs-polluted incineration ashes. Hydrogarnet and tobermorite formations enhanced the strength of the solidified specimens, and meanwhile the formed pollucite was present in a matrix steadily. Leaching test demonstrated that the amount of Cs that leached from the synthesized specimens was very low (0.49 × 10{sup −5}–2.31 × 10{sup −5}) and even lower than that from the reference hollandite-rich synroc (2.0 × 10{sup −2}), although a higher content of Cs was found in the synthesized pollucite specimens (6.0–31.7%) than in the

  18. Controllable synthesis and characterization of CdS quantum dots by a microemulsion-mediated hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Rongrong; Han, Boning; Yang, Lin, E-mail: yanglin@hbu.edu.cn; Yang, Yanmin; Xu, Ying; Mai, Yaohua, E-mail: yaohuamai@hbu.edu.cn

    2016-04-15

    CdS QDs were successfully synthesized through a chemical reaction between cadmium acetate dehydrate and thioacetamide by using a microemulsion-mediated hydrothermal method. The properties of as-prepared CdS QDs can be controlled by using Emulsifier OP and CTAB surfactant, which produce a universal cubic phase and an unusual hexagonal phase, respectively. As a comparison, CdS QDs prepared by CTAB exhibit a better crystallinity and dispersibility. A possible mechanism involving the critical role of surfactant in the formation of crystal structure has also been explored in this paper. It is also found that the crystal size gradually increase with the increase of temperature, and the observation of red-shift in the absorption and emission peaks gives a clear evidence of the quantum confinement effect. All the desired properties of CdS QDs synthesized in this study imply the possibility of the preparation of high quality QDs under the appropriate reaction conditions.

  19. Formation of a hydrophobic and corrosion resistant coating on magnesium alloy via a one-step hydrothermal method.

    Science.gov (United States)

    Zheng, Tianxu; Hu, Yaobo; Zhang, Yuxin; Pan, Fusheng

    2017-11-01

    A hydrophobic coating was fabricated on the surface of magnesium alloy using a simple one-step hydrothermal method with the use of environmentally friendly agent. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and contact angle test were used to characterize the surfaces. Corrosion behavior in a 3.5wt.% NaCl solution was evaluated using OCP time curves test, potentiodynamic polarization test and EIS analysis. The findings show that the substrate is covered by the coating of magnesium hydroxide and magnesium stearate, reaching a contact angle of around 146°. Corrosion behavior show huge improvement, the progress with increase of treatment time could be related to the increased growth rate of coating. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Photocatalytic degradation of methyl orange with W-doped TiO2 synthesized by a hydrothermal method

    International Nuclear Information System (INIS)

    Tian Hua; Ma Junfeng; Li Kang; Li Jinjun

    2008-01-01

    Nanosized W-doped TiO 2 photocatalysts were synthesized by a simple hydrothermal method, and characterized by energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and BET surface area analyzer. The photocatalytic activity of undoped TiO 2 and W-doped TiO 2 photocatalysts was evaluated by the photocatalytic oxidation degradation of methyl orange in aqueous solution. The results show that the photocatalytic activity of the W-doped TiO 2 photocatalyst is much higher than that of undoped TiO 2 , and the optimum percentage of W doped is 2.0 mol%. The enhanced photocatalytic activity of the doped photocatalyst may be attributed to the increase in the charge separation efficiency and the presence of surface acidity

  1. Mechanochemical Effects on the Synthesis of Copper Orthophosphate and cyclo-Tetraphosphate Bulks by the Hydrothermal Hot Pressing Method

    Directory of Open Access Journals (Sweden)

    Isao Tanaka

    2009-01-01

    Full Text Available Copper orthophosphate, Cu3(PO42, and cyclo-tetraphosphates, Cu2P4O12, were synthesized using phosphoric acid and basic copper carbonate, and then treated with a planetary mill for up to 360 minutes. The un-milled and milled samples were characterized by X-ray diffraction (XRD and Fourier transform infrared (FT-IR spectroscopy. SEM images, particle size distribution, specific surface area, UV-Vis reflectance spectra were also used to evaluate the materials. The un-milled and milled materials were used to fabricate copper phosphate bulks by a hydrothermal hot pressing method. The influence of powder condition on the sintering behavior of the copper phosphates was studied.

  2. Carbon/Clay nanostructured composite obtained by hydrothermal method; Compositos nanoestruturados carbono/argila obtidos por metodo hidotermico

    Energy Technology Data Exchange (ETDEWEB)

    Barin, G.B.; Bispo, T.S.; Gimenez, I.F.; Barreto, L.S., E-mail: gabriela.borin@gmail.co [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Souza Filho, A.G. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Fisica

    2010-07-01

    The development of strategies for converting biomass into useful materials, more efficient energy carrier and / or hydrogen storage is shown a key issue for the present and future. Carbon nanostructure can be obtained by severe processing techniques such as arc discharge, chemical deposition and catalyzed pyrolysis of organic compounds. In this study we used hydrothermal methods for obtaining nanostructured composites of carbon / clay. To this end, we used coir dust and special clays. The samples were characterized by infrared spectroscopy, X-ray diffraction and Raman. The presence of the D band at 1350 cm{sup -1} in the Raman spectrum shows the formation of amorphous carbon with particle size of about 8.85 nm. (author)

  3. Synthesis and characterization of hexagonal nano-sized nickel selenide by simple hydrothermal method assisted by CTAB

    Energy Technology Data Exchange (ETDEWEB)

    Sobhani, Azam [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Davar, Fatemeh [Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Salavati-Niasari, Masoud, E-mail: salavati@kashanu.ac.ir [Department of Inorganic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of); Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P.O. Box 87317-51167 (Iran, Islamic Republic of)

    2011-07-01

    Nano-sized nickel selenide powders have been successfully synthesized via an improved hydrothermal route based on the reaction between NiCl{sub 2}.6H{sub 2}O, SeCl{sub 4} and hydrazine (N{sub 2}H{sub 4}.H{sub 2}O) in water, in present of cetyltrimethyl ammonium bromide (CTAB) as surfactant, at various conditions. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy analysis. Effects of temperature, reaction time and reductant agent on the morphology, the particle sizes and the phase of the final products have been investigated. It was found that the phase and morphology of the products could be greatly influenced by these parameters. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. Photoluminescence (PL) was used to study the optical properties of NiSe samples.

  4. The directed preparation of TiO2 nanotubes film on FTO substrate via hydrothermal method for gas sensing application

    Directory of Open Access Journals (Sweden)

    Pham Van Viet

    2016-04-01

    Full Text Available In this research, we directly synthesized TiO2 nanotubes film on Fluorine doped Tin oxide (FTO substrate via hydrothermal method from commercial TiO2 in NaOH solution at 135 ℃ for 24 hours. The samples were characterized by X-ray diffraction (XRD pattern, field emission scanning electron microscopy (FESEM and transmitting electron microscopy (TEM. The average diameter of TiO2 nanotubes (TNTs is about 10–12 nm and their length is about a few hundred nanometers. The sensitivity ability of TNTs increases as the gas concentration increases and developing to the highest sensitivity of TNTs is 2.4 at 700 ppm of the ethanol concentration. The same as the gas concentration, the sensitivity of TNTs increases when the temperature increases. Besides, the sensitivity of samples at 250 ℃ is doubled compared to samples determined at 100 ℃.

  5. Influence of Zr doping on structure and morphology of TiO2 nanorods prepared using hydrothermal method

    Science.gov (United States)

    Muslimin, Masliana; Jumali, Mohammad Hafizuddin; Tee, Tan Sin; Beng, Lee Hock; Hui, Tan Chun; Chin, Yap Chi

    2018-04-01

    The aim of this work is to investigate the effect of Zr doping on TiO2 nanostructure. TiO2 nanorods thin films with different Zr-doping concentrations (6 × 10-3 M, 13 × 10-3 M and 25 × 10-3 M) were successfully prepared using a simple hydrothermal method. The structural and morphological properties of the samples were evaluated using XRD and FESEM respectively. The XRD results revealed that the TiO2 in all samples stabilized as rutile phase. The FESEM micrographs confirmed that TiO2 exist as square like nanorods with blunt tips. Although the crystallographic nature remains unchanged, the introduction of Zr has altered the surface density, structure and morphology of TiO2 which subsequently will have significant effect on its properties.

  6. Development of a hydrothermal method to synthesize spherical ZnSe nanoparticles: Appropriate templates for hollow nanostructures

    Directory of Open Access Journals (Sweden)

    S. Gharibe

    2014-01-01

    Full Text Available Hydrothermal method was used to synthesize pure ZnSe nanosphere materials. The effects of the reducing agent amount, the reaction time and temperature were investigated on the purity of ZnSe. Also, the effects of surfactants such as sodium dodecyl sulfate (SDS (anionic and cetyl trimethylammonium bromide (CTAB (cationic were studied on the morphology of ZnSe. The prepared nanospheres were characterized using XRD, SEM, TEM and UV-Vis spectroscopy. Through these techniques, it was found that the pure ZnSe nanoparticles have a zinc blend structure and in a spherical form with average diameter of 30 nm. DOI: http://dx.doi.org/10.4314/bcse.v28i1.5

  7. Y-Doped ZnO Nanorods by Hydrothermal Method and Their Acetone Gas Sensitivity

    Directory of Open Access Journals (Sweden)

    Peng Yu

    2013-01-01

    Full Text Available Pure and yttrium- (Y- doped (1 at%, 3 at%, and 7 at% ZnO nanorods were synthesized using a hydrothermal process. The crystallography and microstructure of the synthesized samples were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM, and energy dispersive X-ray spectroscopy (EDX. Comparing with pure ZnO nanorods, Y-doped ZnO exhibited improved acetone sensing properties. The response of 1 at% Y-doped ZnO nanorods to 100 ppm acetone is larger than that of pure ZnO nanorods. The response and recovery times of 1 at% Y-doped ZnO nanorods to 100 ppm acetone are about 30 s and 90 s, respectively. The gas sensor based on Y-doped ZnO nanorods showed good selectivity to acetone in the interfere gases of ammonia, benzene, formaldehyde, toluene, and methanol. The formation mechanism of the ZnO nanorods was briefly analyzed.

  8. Facile in situ hydrothermal synthesis of g-C{sub 3}N{sub 4}/SnS{sub 2} composites with excellent visible-light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Fang; Zhao, Lina; Pei, Xule [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang 330063 (China); College of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Xubiao, E-mail: luoxubiao@126.com [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang 330063 (China); College of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Shenglian, E-mail: sllou@hnu.edu.cn [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang 330063 (China); College of Environmental and Chemical Engineering, Nanchang Hangkong University, Nanchang 330063 (China)

    2017-03-01

    The g-C{sub 3}N{sub 4}/SnS{sub 2} composites were prepared by in situ hydrothermal method, and the effect of g-C{sub 3}N{sub 4} content on the physical and chemical properties, and photocatalytic performance of g-C{sub 3}N{sub 4}/SnS{sub 2} composites was investigated. The introduction of g-C{sub 3}N{sub 4} enhanced the visible-light absorption of SnS{sub 2}, and reduced the recombination rate of electron-hole pairs. The photocatalytic performance of g-C{sub 3}N{sub 4}/SnS{sub 2} composites was also obviously influenced by g-C{sub 3}N{sub 4} content, and it was found that 15% g-C{sub 3}N{sub 4}/SnS{sub 2} composite exhibited the highest photocatalytic activity and excellent regeneration, which was attributed to the most efficient charge separation, the largest specific surface area and the formation of dominant active species (h{sup +} and ·O{sub 2}{sup −} radicals) during the photocatalytic process. - Graphical abstract: Photocatalytic mechanism of g-C{sub 3}N{sub 4}/SnS{sub 2} composites. - Highlights: • g-C{sub 3}N{sub 4}/SnS{sub 2} composites were fabricated by a in situ hydrothermal process. • g-C{sub 3}N{sub 4} content was optimized, and the optimal g-C{sub 3}N{sub 4} content is 15%. • 15% g-C{sub 3}N{sub 4}/SnS{sub 2} shows the highest visible-light photocatalytic activity. • g-C{sub 3}N{sub 4}/SnS{sub 2} composites exhibit excellent reusability.

  9. Microstructure and magnetic properties of MFe2O4 (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method

    Science.gov (United States)

    Wang, Wei; Ding, Zui; Zhao, Xiruo; Wu, Sizhu; Li, Feng; Yue, Ming; Liu, J. Ping

    2015-05-01

    Three kinds of spinel ferrite nanocrystals, MFe2O4 (M = Co, Ni, and Mn), are synthesized using colloid mill and hydrothermal method. During the synthesis process, a rapid mixing and reduction of cations with sodium borohydride (NaBH4) take place in a colloid mill then through a hydrothermal reaction, a slow oxidation and structural transformation of the spinel ferrite nanocrystals occur. The phase purity and crystal lattice parameters are estimated by X-ray diffraction studies. Scanning electron microscopy and transmission electron microscopy images show the morphology and particle size of the as-synthesized ferrite nanocrystals. Raman spectrum reveals active phonon modes at room temperature, and a shifting of the modes implies cation redistribution in the tetrahedral and octahedral sites. Magnetic measurements show that all the obtained samples exhibit higher saturation magnetization (Ms). Meanwhile, experiments demonstrate that the hydrothermal reaction time has significant effects on microstructure, morphologies, and magnetic properties of the as-synthesized ferrite nanocrystals.

  10. Instrumentation and measurement method for the ATLAS test facility

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Byong Jo; Chu, In Chul; Eu, Dong Jin; Kang, Kyong Ho; Kim, Yeon Sik; Song, Chul Hwa; Baek, Won Pil

    2007-03-15

    An integral effect test loop for pressurized water reactors (PWRs), the ATLAS is constructed by thermal-hydraulic safety research division in KAERI. The ATLAS facility has been designed to have the length scale of 1/2 and area scale of 1/144 compared with the reference plant, APR1400 which is a Korean evolution type nuclear reactors. A total 1300 instrumentations is equipped in the ATLAS test facility. In this report, the instrumentation of ATLAS test facility and related measurement methods were introduced.

  11. Development of anti-biofouling methods for gate facilities

    International Nuclear Information System (INIS)

    Fukuoka, Mari; Akamine, Kenichi; Iai, Yuuichi; Takatoo, Norihiro; Fukushima, Noriaki

    2016-01-01

    In the maintenance and management of gate facilities, a large sum of money and labor are required to remove and clean organisms that attach themselves to the facilities. That is why we developed two anti-biofouling systems, one that uses a weak electric current and another that uses ultrasonic waves. We carried out basic examinations and actual environment examinations to verify the effects of these methods. As a result, it has been confirmed that these methods effectively anti-foul the parts they are applied to, and that they can be used on gate facilities. In the future, we will evaluate their adaptability to aqueducts, such as those used in thermal and nuclear power plants, and marine structures, such as floating breakwaters, in addition to gate facilities. (author)

  12. Sodium cleaning and disposal methods in experimental facilities

    International Nuclear Information System (INIS)

    Rajan, K.K.; Gurumoorthy, K.; Rajan, M.; Kale, R.D.

    1997-01-01

    At Indira Gandhi Centre for Atomic Research, major sodium facilities are designed and operated at Engineering Development Group as a part of development programme towards experimental and Prototype Fast Reactor. After the test programme many equipment and components were removed from the sodium facilities and sodium removal and disposal was carried out. The experience gained in different cleaning methods and waste sodium disposal are discussed. (author)

  13. Synthesis of high saturation magnetic iron oxide nanomaterials via low temperature hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Bhavani, P.; Rajababu, C.H. [Department of Materials Science & Nanotechnology, Yogivemana University, Vemanapuram 516003, Kadapa (India); Arif, M.D. [Environmental Magnetism Laboratory, Indian Institute of Geomagnetism (IIG), Navi Mumbai 410218, Mumbai (India); Reddy, I. Venkata Subba [Department of Physics, Gitam University, Hyderabad Campus, Rudraram, Medak 502329 (India); Reddy, N. Ramamanohar, E-mail: manoharphd@gmail.com [Department of Materials Science & Nanotechnology, Yogivemana University, Vemanapuram 516003, Kadapa (India)

    2017-03-15

    Iron oxide nanoparticles (IONPs) were synthesized through a simple low temperature hydrothermal approach to obtain with high saturation magnetization properties. Two series of iron precursors (sulfates and chlorides) were used in synthesis process by varying the reaction temperature at a constant pH. The X-ray diffraction pattern indicates the inverse spinel structure of the synthesized IONPs. The Field emission scanning electron microscopy and high resolution transmission electron microscopy studies revealed that the particles prepared using iron sulfate were consisting a mixer of spherical (16–40 nm) and rod (diameter ~20–25 nm, length <100 nm) morphologies that synthesized at 130 °C, while the IONPs synthesized by iron chlorides are found to be well distributed spherical shapes with size range 5–20 nm. On other hand, the IONPs synthesized at reaction temperature of 190 °C has spherical (16–46 nm) morphology in both series. The band gap values of IONPs were calculated from the obtained optical absorption spectra of the samples. The IONPs synthesized using iron sulfate at temperature of 130 °C exhibited high saturation magnetization (M{sub S}) of 103.017 emu/g and low remanant magnetization (M{sub r}) of 0.22 emu/g with coercivity (H{sub c}) of 70.9 Oe{sub ,} which may be attributed to the smaller magnetic domains (d{sub m}) and dead magnetic layer thickness (t). - Highlights: • Comparison of iron oxide materials prepared with Fe{sup +2}/Fe{sup +3} sulfates and chlorides at different temperatures. • We prepared super-paramagnetic and soft ferromagnetic magnetite nanoparticles. • We report higher saturation magnetization with lower coercivity.

  14. Dielectric response and electric conductivity of ceramics obtained from BiFeO{sub 3} synthesized by microwave hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Chybczyńska, K.; Markiewicz, E., E-mail: ewamar@ifmpan.poznan.pl; Błaszyk, M.; Hilczer, B.; Andrzejewski, B.

    2016-06-25

    BiFeO{sub 3} powder which formed ball-like structures resembling flowers was obtained by microwave hydrothermal synthesis. The flowers were of a dozen or so μm in diameter and the thickness of the crystallites forming petals could be controlled. The material was characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Dielectric response of ceramics obtained from the powder contained three extrinsic contributions, which could be correlated with the differences in temperature variation of the ac conductivity. The dielectric relaxation between 150 K and 300 K was related to reorientations of Fe{sup 3+}–Fe{sup 2+} dipoles and characterized by an activation energy of 0.4 eV, which was independent of the petal thickness. The dielectric and electric response in the range 300 K ÷ 450 K usually ascribed to the grain boundary and interfacial polarization effect was diffused and could not be characterized. Above 450 K the activation energy of dc conductivity was 1.73 eV and 1.52 eV for ceramics consisting of crystallites of mean thickness of 160 nm and 260 nm, respectively. The energies, which are considerably higher than those reported earlier for BFO nanoceramics, were discussed considering the interactions between oxygen vacancies and size scaled ferroelectric domain walls, which in BiFeO{sub 3} are associated with electrostatic potential steps. - Highlights: • BiFeO{sub 3} with controllable thickness of crystallites was synthesized hydrothermally. • The powder and ceramics obtained were characterized by XRD, SEM and XPS methods. • Dielectric response of the ceramics is correlated with the ac conductivity. • Size-scaled ferroelectric domains and oxygen vacancies interact above 450 K.

  15. Hydrothermal Processes

    Science.gov (United States)

    German, C. R.; von Damm, K. L.

    2003-12-01

    What is Hydrothermal Circulation?Hydrothermal circulation occurs when seawater percolates downward through fractured ocean crust along the volcanic mid-ocean ridge (MOR) system. The seawater is first heated and then undergoes chemical modification through reaction with the host rock as it continues downward, reaching maximum temperatures that can exceed 400 °C. At these temperatures the fluids become extremely buoyant and rise rapidly back to the seafloor where they are expelled into the overlying water column. Seafloor hydrothermal circulation plays a significant role in the cycling of energy and mass between the solid earth and the oceans; the first identification of submarine hydrothermal venting and their accompanying chemosynthetically based communities in the late 1970s remains one of the most exciting discoveries in modern science. The existence of some form of hydrothermal circulation had been predicted almost as soon as the significance of ridges themselves was first recognized, with the emergence of plate tectonic theory. Magma wells up from the Earth's interior along "spreading centers" or "MORs" to produce fresh ocean crust at a rate of ˜20 km3 yr-1, forming new seafloor at a rate of ˜3.3 km2 yr-1 (Parsons, 1981; White et al., 1992). The young oceanic lithosphere formed in this way cools as it moves away from the ridge crest. Although much of this cooling occurs by upward conduction of heat through the lithosphere, early heat-flow studies quickly established that a significant proportion of the total heat flux must also occur via some additional convective process (Figure 1), i.e., through circulation of cold seawater within the upper ocean crust (Anderson and Silbeck, 1981). (2K)Figure 1. Oceanic heat flow versus age of ocean crust. Data from the Pacific, Atlantic, and Indian oceans, averaged over 2 Ma intervals (circles) depart from the theoretical cooling curve (solid line) indicating convective cooling of young ocean crust by circulating seawater

  16. Hydrothermal processes above the Yellowstone magma chamber: Large hydrothermal systems and large hydrothermal explosions

    Science.gov (United States)

    Morgan, L.A.; Shanks, W.C. Pat; Pierce, K.L.

    2009-01-01

    Hydrothermal explosions are violent and dramatic events resulting in the rapid ejection of boiling water, steam, mud, and rock fragments from source craters that range from a few meters up to more than 2 km in diameter; associated breccia can be emplaced as much as 3 to 4 km from the largest craters. Hydrothermal explosions occur where shallow interconnected reservoirs of steam- and liquid-saturated fluids with temperatures at or near the boiling curve underlie thermal fields. Sudden reduction in confi ning pressure causes fluids to fl ash to steam, resulting in signifi cant expansion, rock fragmentation, and debris ejection. In Yellowstone, hydrothermal explosions are a potentially signifi cant hazard for visitors and facilities and can damage or even destroy thermal features. The breccia deposits and associated craters formed from hydrothermal explosions are mapped as mostly Holocene (the Mary Bay deposit is older) units throughout Yellowstone National Park (YNP) and are spatially related to within the 0.64-Ma Yellowstone caldera and along the active Norris-Mammoth tectonic corridor. In Yellowstone, at least 20 large (>100 m in diameter) hydrothermal explosion craters have been identifi ed; the scale of the individual associated events dwarfs similar features in geothermal areas elsewhere in the world. Large hydrothermal explosions in Yellowstone have occurred over the past 16 ka averaging ??1 every 700 yr; similar events are likely in the future. Our studies of large hydrothermal explosion events indicate: (1) none are directly associated with eruptive volcanic or shallow intrusive events; (2) several historical explosions have been triggered by seismic events; (3) lithic clasts and comingled matrix material that form hydrothermal explosion deposits are extensively altered, indicating that explosions occur in areas subjected to intense hydrothermal processes; (4) many lithic clasts contained in explosion breccia deposits preserve evidence of repeated fracturing

  17. Modelling of hydrothermal characteristics of centrifugal nozzles

    International Nuclear Information System (INIS)

    Yarkho, A.A.; Omelchenko, M.P.; Borshchev, V.A.

    1990-01-01

    Presented for the first time is a method of recalculating the hydrothermal characteristics of centrifugal nozzles obtained in laboratory conditions for full-scale nozzles. From the experimental hydrothermal characteristics of nozzles observed in the laboratory it is allowed to calculate the hydrothermal characteristics of any other centrifugal nozzle whose diameter and dimensionless geometric characteristic are known

  18. Synthesis of three-dimensional rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures using one-pot hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Guo, E-mail: guogao@sjtu.edu.cn [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Qiang; Cheng, Xin-Bing [Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Sun, Rongjin [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Shapter, Joseph G., E-mail: joe.shapter@flinders.edu.au [School of Chemical and Physical Sciences, Flinders University, Bedford Park, Adelaide 5042 (Australia); Yin, Ting [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Cui, Daxiang, E-mail: dxcui@sjtu.edu.cn [Institute of Nano Biomedicine and Engineering, Department of Instrument Science and Technology, Key Laboratory for Thin Film and Microfabrication Technology of Ministry of Education, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-11-15

    Rechargeable lithium ion batteries (LIBs) are currently the dominant power source for all sorts of electronic devices due to their low cost and high energy density. The cycling stability of LIBs is significantly compromised due to the broad satellite peak for many anode materials. Herein, we develop a facile hydrothermal process for preparing rare-earth (Er, Tm) ions doped three-dimensional (3D) transition metal oxides/carbon hybrid nanocomposites, namely CNTs-GO-Fe{sub 3}O{sub 4}, CNTs-GO-Fe{sub 3}O{sub 4}-Er and CNTs-GO-Fe{sub 3}O{sub 4}-Tm. The GO sheets and CNTs are interlinked by ultrafine Fe{sub 3}O{sub 4} nanoparticles forming three-dimensional (3D) architectures. When evaluated as anode materials for LIBs, the CNTs-GO-Fe{sub 3}O{sub 4} hybrid composites have a bigger broad satellite peak. As for the CNTs-GO-Fe{sub 3}O{sub 4}-Er and CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites, the broad satellite peak can be completely eliminated. When the current density changes from 5 C back to 0.1 C, the capacity of CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites can recover to 1023.9 mAhg{sup −1}, indicating an acceptable rate capability. EIS tests show that the charge transfer resistance does not change significantly after 500 cycles, demonstrating that the cycling stability of CNTs-GO-Fe{sub 3}O{sub 4}-Tm hybrid composites are superior to CNTs-GO-Fe{sub 3}O{sub 4} and CNTs-GO-Fe{sub 3}O{sub 4}-Er hybrid structures. - Graphical abstract: One-pot hydrothermal method for synthesis of rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures as anode materials of LIBs have been reported. - Highlights: • We report the synthesis of rare-earth ions doped CNTs-GO-Fe{sub 3}O{sub 4} hybrid structures. • The hybrid structures can improve the cycling stability of lithium storage. • As for anode materials, the broad satellite peak can be completely eliminated. • When the rate return back to 0.1 C, the capacity can recover to 1023.9 mAhg{sup −1}. • After 500

  19. Synthesis of three-dimensional rare-earth ions doped CNTs-GO-Fe3O4 hybrid structures using one-pot hydrothermal method

    International Nuclear Information System (INIS)

    Gao, Guo; Zhang, Qiang; Cheng, Xin-Bing; Sun, Rongjin; Shapter, Joseph G.; Yin, Ting; Cui, Daxiang

    2015-01-01

    Rechargeable lithium ion batteries (LIBs) are currently the dominant power source for all sorts of electronic devices due to their low cost and high energy density. The cycling stability of LIBs is significantly compromised due to the broad satellite peak for many anode materials. Herein, we develop a facile hydrothermal process for preparing rare-earth (Er, Tm) ions doped three-dimensional (3D) transition metal oxides/carbon hybrid nanocomposites, namely CNTs-GO-Fe 3 O 4 , CNTs-GO-Fe 3 O 4 -Er and CNTs-GO-Fe 3 O 4 -Tm. The GO sheets and CNTs are interlinked by ultrafine Fe 3 O 4 nanoparticles forming three-dimensional (3D) architectures. When evaluated as anode materials for LIBs, the CNTs-GO-Fe 3 O 4 hybrid composites have a bigger broad satellite peak. As for the CNTs-GO-Fe 3 O 4 -Er and CNTs-GO-Fe 3 O 4 -Tm hybrid composites, the broad satellite peak can be completely eliminated. When the current density changes from 5 C back to 0.1 C, the capacity of CNTs-GO-Fe 3 O 4 -Tm hybrid composites can recover to 1023.9 mAhg −1 , indicating an acceptable rate capability. EIS tests show that the charge transfer resistance does not change significantly after 500 cycles, demonstrating that the cycling stability of CNTs-GO-Fe 3 O 4 -Tm hybrid composites are superior to CNTs-GO-Fe 3 O 4 and CNTs-GO-Fe 3 O 4 -Er hybrid structures. - Graphical abstract: One-pot hydrothermal method for synthesis of rare-earth ions doped CNTs-GO-Fe 3 O 4 hybrid structures as anode materials of LIBs have been reported. - Highlights: • We report the synthesis of rare-earth ions doped CNTs-GO-Fe 3 O 4 hybrid structures. • The hybrid structures can improve the cycling stability of lithium storage. • As for anode materials, the broad satellite peak can be completely eliminated. • When the rate return back to 0.1 C, the capacity can recover to 1023.9 mAhg −1 . • After 500 cycles, the hybrid structures still exhibited excellent cycling stability

  20. Influence of pH on optoelectronic properties of zinc sulphide thin films prepared using hydrothermal and spin coating method

    Science.gov (United States)

    Choudapur, V. H.; Bennal, A. S.; Raju, A. B.

    2018-04-01

    The ZnS nanomaterial is synthesized by hydrothermal method under optimized conditions using Zinc acetate and sodium sulphide as precursors. The Zinc Sulphide thin films are obtained by simple spin coating method with high optical transmittance. The prepared thin films are adhesive and uniform. The x-ray diffraction analysis showed that the films are polycrystalline in cubic phase with the preferred orientation along (111) direction. Current-voltage curves were recorded at room temperature using Keithley 617 programmable electrometer and conductivity is calculated for the film coated on ITO by two probe method. The pH of the solution is varied by using ammonia and hydrochloric acid. The comparative studies of effect of pH on the morphology, crystallanity and optoelectronic properties of the films are studied. It is observed that the pH of the solution has large influence on optoelectronic properties. The thin film prepared with neutral pH has higher crystallanity, bandgap and conductivity as compared to the samples prepared in acidic or basic solutions.

  1. A research on threat (hazard) categorization method for nuclear facilities

    International Nuclear Information System (INIS)

    Tang Rongyao; Xu Xiaoxiao; Zhang Jiangang; Zhao Bin; Wang Xuexin

    2011-01-01

    The threat categorization method suggested by International Atomic Energy Agency (IAEA) and hazard categorization standard by the Department of Energy of United States (USDOE) for nuclear facilities are compared and discussed in this paper. The research shows the two types of categorization method for nuclear facilities are similar, though each has its own specialty. The categorization method suggested by IAEA for the purpose of emergency planning is quite completed and updated. The categorization method of DOE is advanced in its operability, and fits for safety surveillance. But the dispersible radioactive material thresholds used for categorization need to be updated. The threshold of category 3 is somewhat disputable for many reasons. The recommended categorization method for China is also given in this paper. (author)

  2. Structure and phase transition of BiFeO{sub 3} cubic micro-particles prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jian-Ping, E-mail: zhoujp@snnu.edu.cn [College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Yang, Ruo-Lin; Xiao, Rui-Juan; Chen, Xiao-Ming [College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China); Deng, Chao-Yong [Department of Electronic Science, Guizhou University, Guizhou Guiyang 550025 (China)

    2012-11-15

    Graphical abstract: Bismuth ferrite (BiFeO{sub 3}) cubic micro-particles with smooth surfaces were synthesized. BiFeO{sub 3} has a hexagonal perovskite structure with a space group R3c below 370 °C and rhombohedral perovskite structure with a space group R3m below 755 °C, undergoes a phase transition in the temperature range of 755–817 °C to a cubic structure, then decompose to liquid and Fe{sub 2}O{sub 3} above 939 °C. Highlights: ► BiFeO{sub 3} micro-particles with smooth surface were synthesized by hydrothermal method. ► BiFeO{sub 3} enjoys hexagonal structure with well element ratio and chemical valence. ► BiFeO{sub 3} transition from rhombohedral phase to cubic phase lasts 60 °C. -- Abstract: Single-phase bismuth ferrite (BiFeO{sub 3}) powders were synthesized with a hydrothermal method by controlling the experimental conditions carefully. The powder structure, morphology and composition were characterized by using X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscope, Raman measurement and X-ray photoelectron spectroscopy. The particles change from irregular agglomerations to regular cubes with increasing KOH concentration. The large BiFeO{sub 3} cubic particles enjoy much smooth surfaces with well-matched element ratio (Bi:Fe:O = 1:1:3) and chemical valence (Bi{sup 3+}, Fe{sup 3+} and O{sup 2−}). The high temperature XRD and differential scanning calorimetry show that BiFeO{sub 3} powders have a hexagonal perovskite structure with a space group R3c below 370 °C and a rhombohedral structure with a space group R3m below 755 °C. BiFeO{sub 3} undergoes a phase transition in the temperature range of 755–817 °C from rhombohedral structure to a cubic phase, then decomposes to liquid and Fe{sub 2}O{sub 3} above 939 °C.

  3. Structure and phase transition of BiFeO3 cubic micro-particles prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Zhou, Jian-Ping; Yang, Ruo-Lin; Xiao, Rui-Juan; Chen, Xiao-Ming; Deng, Chao-Yong

    2012-01-01

    Graphical abstract: Bismuth ferrite (BiFeO 3 ) cubic micro-particles with smooth surfaces were synthesized. BiFeO 3 has a hexagonal perovskite structure with a space group R3c below 370 °C and rhombohedral perovskite structure with a space group R3m below 755 °C, undergoes a phase transition in the temperature range of 755–817 °C to a cubic structure, then decompose to liquid and Fe 2 O 3 above 939 °C. Highlights: ► BiFeO 3 micro-particles with smooth surface were synthesized by hydrothermal method. ► BiFeO 3 enjoys hexagonal structure with well element ratio and chemical valence. ► BiFeO 3 transition from rhombohedral phase to cubic phase lasts 60 °C. -- Abstract: Single-phase bismuth ferrite (BiFeO 3 ) powders were synthesized with a hydrothermal method by controlling the experimental conditions carefully. The powder structure, morphology and composition were characterized by using X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscope, Raman measurement and X-ray photoelectron spectroscopy. The particles change from irregular agglomerations to regular cubes with increasing KOH concentration. The large BiFeO 3 cubic particles enjoy much smooth surfaces with well-matched element ratio (Bi:Fe:O = 1:1:3) and chemical valence (Bi 3+ , Fe 3+ and O 2− ). The high temperature XRD and differential scanning calorimetry show that BiFeO 3 powders have a hexagonal perovskite structure with a space group R3c below 370 °C and a rhombohedral structure with a space group R3m below 755 °C. BiFeO 3 undergoes a phase transition in the temperature range of 755–817 °C from rhombohedral structure to a cubic phase, then decomposes to liquid and Fe 2 O 3 above 939 °C.

  4. Sensitive and selective detection of Hg2+ and Cu2+ ions by fluorescent Ag nanoclusters synthesized via a hydrothermal method

    Science.gov (United States)

    Liu, Jing; Ren, Xiangling; Meng, Xianwei; Fang, Zheng; Tang, Fangqiong

    2013-09-01

    An easily prepared fluorescent Ag nanoclusters (Ag NCs) probe for the sensitive and selective detection of Hg2+ and Cu2+ ions was developed here. The Ag NCs were synthesized by using polymethacrylic acid sodium salt as a template via a convenient hydrothermal process. The as-prepared fluorescent Ag NCs were monodispersed, uniform and less than 2 nm in diameter, and can be quenched in the presence of mercury (Hg2+) or copper (Cu2+) ions. Excellent linear relationships existed between the quenching degree of the Ag NCs and the concentrations of Hg2+ or Cu2+ ions in the range of 10 nM to 20 μM or 10 nM to 30 μM, respectively. By using ethylenediaminetetraacetate (EDTA) as the masking agent of Cu2+, Hg2+ was exclusively detected in coexistence with Cu2+ with high sensitivity (LOD = 10 nM), which also provided a reusable detection method for Cu2+. Furthermore, the different quenching phenomena caused by the two metals ions such as changes in visible colour, shifts of UV absorbance peaks and changes in size of Ag NCs make it easy to distinguish between them. Therefore the easily synthesized fluorescent Ag NCs may have great potential as Hg2+ and Cu2+ ions sensors.An easily prepared fluorescent Ag nanoclusters (Ag NCs) probe for the sensitive and selective detection of Hg2+ and Cu2+ ions was developed here. The Ag NCs were synthesized by using polymethacrylic acid sodium salt as a template via a convenient hydrothermal process. The as-prepared fluorescent Ag NCs were monodispersed, uniform and less than 2 nm in diameter, and can be quenched in the presence of mercury (Hg2+) or copper (Cu2+) ions. Excellent linear relationships existed between the quenching degree of the Ag NCs and the concentrations of Hg2+ or Cu2+ ions in the range of 10 nM to 20 μM or 10 nM to 30 μM, respectively. By using ethylenediaminetetraacetate (EDTA) as the masking agent of Cu2+, Hg2+ was exclusively detected in coexistence with Cu2+ with high sensitivity (LOD = 10 nM), which also provided a

  5. Enhanced fluorescence imaging performance of hydrophobic colloidal ZnO nanoparticles by a facile method

    International Nuclear Information System (INIS)

    Zang, Zhigang; Tang, Xiaosheng

    2015-01-01

    Highlights: • A dual phase hydrothermal method was developed to synthesize ZnO nanoparticles. • ZnO nanoparticles show a stability and solubility in the aqueous environment. • ZnO nanoparticles with a blue emission wavelength at around 420 nm and small size (30 nm). • ZnO nanoparticles as biological labeling agent was also shown. - Abstract: A facile synthesis method for the formation of ZnO nanoparticles by using a double-phase reaction was demonstrated in this paper. The morphology of the synthesized ZnO nanoparticles shows a flower-shape. Hydrogen peroxide was used as a unique oxygenic source to promote the formation of ZnO in the presence of organic zinc precursor. The as-synthesized ZnO nanoparticles also show a stability and solubility in the aqueous environment. The structure and properties of ZnO nanoparticles were investigated by the transmission electron microscopy (TEM) and X-ray diffraction (XRD) as well as UV–vis and photoluminescence spectroscopy. The as-prepared hydrophobic colloidal ZnO nanoparticles could be modified to become water-soluble via ligand exchange with amineothanethiol⋅HCl while retaining the photoluminescence properties. In addition, the potential application for biological label of water-soluble ZnO nanoparticles were also demonstrated. These results not only have applications towards using colloidal ZnO nanoparticles effectively in biological fluorescence imaging, but also promote its application in the field of targeted drug delivery

  6. Controlled synthesis of La1−xSrxCrO3 nanoparticles by hydrothermal method with nonionic surfactant and their ORR activity in alkaline medium

    International Nuclear Information System (INIS)

    Choi, Bo Hyun; Park, Shin-Ae; Park, Bong Kyu; Chun, Ho Hwan; Kim, Yong-Tae

    2013-01-01

    Graphical abstract: We demonstrate that Sr-doped LaCrO 3 nanoparticles were successfully prepared by the hydrothermal synthesis method using the nonionic surfactant Triton X-100 and the applicability of La 1−x Sr x CrO 3 to oxygen reduction reaction (ORR) electrocatalysis in an alkaline medium. Compared with the nanoparticles synthesized by the coprecipitation method, they showed enhanced ORR activity. - Highlights: • Sr-doped LaCrO 3 nanoparticles were successfully prepared by the hydrothermal method using the nonionic surfactant. • Homogeneously shaped and sized Sr-doped LaCrO 3 nanoparticles were readily obtained. • Compared with the nanoparticles synthesized by the coprecipitation method, they showed an enhanced ORR activity. • The main origin was revealed to be the decreased particle size due to the nonionic surfactant. - Abstract: Sr-doped LaCrO 3 nanoparticles were prepared by the hydrothermal method with the nonionic surfactant Triton X-100 followed by heat treatment at 1000 °C for 10 h. The obtained perovskite nanoparticles had smaller particle size (about 100 nm) and more uniform size distribution than those synthesized by the conventional coprecipitation method. On the other hand, it was identified with the material simulation that the electronic structure change by Sr doping was negligible, because the initially unfilled e g -band was not affected by the p-type doping. Finally, the perovskite nanoparticles synthesized by hydrothermal method showed much higher ORR activity by over 200% at 0.8 V vs. RHE than those by coprecipitation method

  7. Morphology and phase transformations of tin oxide nanostructures synthesized by the hydrothermal method in the presence of dicarboxylic acids

    International Nuclear Information System (INIS)

    Zima, Tatyana; Bataev, Ivan

    2016-01-01

    A new approach to the synthesis of non-stoichiometric tin oxide structures with different morphologies and the phase compositions has been evaluated. The nanostructures were synthesized by hydrothermal treatment of the mixtures of dicarboxylic acids ― aminoterephthalic or oxalic ― with nanocrystalline SnO 2 powder, which was obtained via the sol-gel technology. The products were characterized by Raman and IR spectroscopy, SEM, HRTEM, and XRD analysis. It was shown that the controlled addition of a dicarboxylic acid leads not only to a change in the morphology of the nanostructures, but also to SnO 2 –SnO 2 /Sn 3 O 4 –Sn 3 O 4 –SnO phase transformations. A single-phase Sn 3 O 4 in the form of the well-separated hexagonal nanoplates and mixed SnO 2 /Sn 3 O 4 phases in the form of hierarchical flower-like structures were obtained in the presence of organic additives. The effects of concentration, redox activity of the acids and heat treatment on the basic characteristics of the synthesized tin oxide nanostructures and phase transformations in the synthesized materials are discussed. - Graphical abstract: The controlled addition of aminoterephthalic or oxalic acid leads not only to a change in the morphology of the nanostructures, but also to SnO 2 –SnO 2 /Sn 3 O 4 –Sn 3 O 4 –SnO phase transformations. - Highlights: • A new approach to the synthesis of non-stoichiometric tin oxide structures is studied. • Tin oxide structures are synthesized via hydrothermal method with dicarboxylic acids. • Morphology and phase composition are changed with redox activity and dosage of acid. • The redox activity of acid has an effect on ratio of SnO and SnO 2 in crystal structure. • A pure phase Sn 3 O 4 nanoplates and SnO 2 /Sn 3 O 4 hierarchical structures are formed.

  8. Influence of Sn ion doping on the photocatalytic performance of V2O5 nanorods prepared by hydrothermal method

    Science.gov (United States)

    Rajeshwari, S.; Santhosh Kumar, J.; Rajendrakumar, R. T.; Ponpandian, N.; Thangadurai, P.

    2018-02-01

    Pure and different concentrations of Sn4+ doped V2O5 (Sn:V2O5) nanorods were synthesized by hydrothermal method. The Sn:V2O5 nanorods obtained were orthorhombic in structure. No secondary phase was observed up to 10% of Sn doping, but beyond that, there evolved a secondary phase of SnO2. Microstructural analysis revealed the morphology of V2O5 as nanorods and platelets like structure. Presence of V, O and Sn elements in the samples was confirmed by energy dispersive spectroscopy. The V2O5 nanorods have shown a strong absorption in the visible region and the band gap energy was obtained to be varying from 2.21 to 2.26 eV as a function of Sn ion doping. Photocatalytic studies on methylene blue (MB) under visible light irradiation showed that the 3% Sn:V2O5 had effectively degraded MB up to a maximum degradation of 96% and further increase in Sn content had decreased the photodegradation due to higher recombination rate of photogenerated electrons. The mechanism of photodegradation was completely understood and the OH· radicals have played a dominant role in the photodegradation of the organic dyes.

  9. Selective synthesis of vitamin K3 over mesoporous NbSBA-15 catalysts synthesized by an efficient hydrothermal method.

    Science.gov (United States)

    Selvaraj, M; Park, D-W; Kim, I; Kawi, S; Ha, C S

    2012-08-28

    Well hexagonally ordered NbSBA-15 catalysts synthesized by an efficient hydrothermal method were used, for the first time, for the selective synthesis of vitamin K(3) by liquid-phase oxidation of 2-methyl-1-naphthol (2MN1-OH) under various reaction conditions. The recyclable NbSBA-15 catalysts were also reused to find their catalytic activities. To investigate the leaching of non-framework niobium species on the surface of silica networks, the results of original and recyclable NbSBA-15 catalysts were correlated and compared. To find an optimum condition for the selective synthesis of vitamin K(3), the washed NbSBA-15(2.2pH) was extensively used in this reaction with various reaction parameters such as temperature, time and ratios of reactant (2M1N-OH to H(2)O(2)), and the obtained results were also demonstrated. Additionally, the liquid-phase oxidation of 2M1N-OH was carried out with different solvents to find the best solvent with a good catalytic activity. Based on the all catalytic studies, the vitamin K(3) selectivity (97.3%) is higher in NbSBA-15(2.2pH) than that of other NbSBA-15 catalysts, and the NbSBA-15(2.2pH) is found to be a highly active and eco-friendly heterogeneous catalyst for the selective synthesis of vitamin K(3).

  10. Structural and room temperature ferromagnetic properties of Ni doped ZnO nanoparticles via low-temperature hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Kun; Liu, Changzhen, E-mail: liuchangzhen94@163.com; Chen, Rui; Fang, Xiaoxiang; Wu, Xiuling; Liu, Jie

    2016-12-01

    A series of Zn{sub 1−x}Ni{sub x}O (x=0, 1%, 3%, 5%) nanoparticles have been synthesized via a low-temperature hydrothermal method. Influence of Ni doping concentration on the structure, morphology, optical properties and magnetism of the samples was investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, UV–vis spectrophotometer and vibrating sample magnetometer instruments. The results show that the undoped and doped ZnO nanoparticles are both hexagonal wurtzite structures. The surface analysis was performed using X-ray photoelectron spectroscopic studies. The images of SEM reveal that the structure of pure ZnO and Ni doped samples are nanoparticles which intended to form flakes with thickness of few nanometers, being overlain with each one to develop the network with some pores and voids. Based on the ultraviolet–visible (UV–vis) spectroscopy analysis, it indicates that the band gap energy decreases with the increasing concentration of Ni. Furthermore, The Ni doped ZnO samples didn't exhibit higher ultraviolet-light-driven photocatalytic activity compared to the undoped ZnO sample. Vibrating sample magnetometer was used for the magnetic property investigations, and the result indicates that room temperature ferromagnetism property of 3% Ni doped sample is attributed to oxygen vacancy and interaction between doped ions.

  11. Electrochemical properties of Li2 FeSiO4 /C nanocomposites prepared by sol-gel and hydrothermal methods

    Science.gov (United States)

    Kumar, Ajay; Jayakumar, O. D.; Naik, Vaman M.; Nazri, Gholam A.; Naik, Ratna

    Li2FeSiO4 is considered as potential cathode material for next generation lithium ion batteries because of its high specific theoretical capacity, low cost, and safety. However, it suffers from poor electronic conductivity and slow lithium ion diffusion in the solid phase. To address these issues, we have studied mesoporous Li2FeSiO4/C composites synthesized by sol-gel (SG) and hydrothermal (HT) methods using tri-block copolymer (P123) as carbon source and structure directing agent. The structure and morphology of the composites were characterized by XRD, SEM and TEM and the surface area and pore size distribution were measured by using N2 adsorption/desorption. Galvanostatic cycling, electrochemical impedance spectroscopy, and cyclic voltammetry were used to evaluate the electrochemical performance of the Li2FeSiO4/C composites. The Li2FeSiO4/C (HT) composites show a superior electrochemical performance compared to Li2FeSiO4/C (SG). At C/30 rate, the discharge capacity of Li2FeSiO4/C (HT) reached ~276 mAh/g in the 1.5-4.6 V window and shows better rate capability and stability at high rates. We attribute the improved electrochemical performance of Li2FeSiO4/C (HT) to its large surface area and reduced particle size. The details of the study will be presented.

  12. Structural and optical study of CaF{sub 2} nanoparticles produced by a microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, Claudiane dos S., E-mail: cdsantos20@gmail.com; Valerio, Mário E.G.

    2016-11-15

    CaF{sub 2} nanoparticles were synthesized by the microwave-assisted hydrothermal method. With the addition of the ethylenediamine (EDA) as chelating agent, the size of the particles was reduced. The CaF{sub 2} exhibit single phase identified for X-ray diffraction (XRD) and confirmed by Rietveld refinement. Scanning electron microscopy (SEM) images showed nanoparticles with non-uniform morphology and statistical analysis of collections of particles reviewed that the EDA decreases both the average particle size and average aspect ratio of the particles. The chemical composition of the surface of the particles was investigated by X-ray Photoelectron Spectroscopy (XPS) and the results indicated the presence of reasonable amounts of hydroxyl groups and oxygen ions in the samples produced with EDA. Radioluminescence (RL) measurements showed that both types of nanoparticles presented intrinsic scintillation emission formed by two main bands and that the CaF{sub 2} samples produced without EDA presented higher emission intensity. The broad RL band centered at approximately 293 nm is related to self-trapped exciton (STE) emission of calcium fluoride, while the band at 428 nm can be due to the presence of F centers. The STE excitation and optical band gap were measured through photoluminescent excitation spectra in the VUV range.

  13. MnO2 prepared by hydrothermal method and electrochemical performance as anode for lithium-ion battery.

    Science.gov (United States)

    Feng, Lili; Xuan, Zhewen; Zhao, Hongbo; Bai, Yang; Guo, Junming; Su, Chang-Wei; Chen, Xiaokai

    2014-01-01

    Two α-MnO2 crystals with caddice-clew-like and urchin-like morphologies are prepared by the hydrothermal method, and their structure and electrochemical performance are characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), galvanostatic cell cycling, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The morphology of the MnO2 prepared under acidic condition is urchin-like, while the one prepared under neutral condition is caddice-clew-like. The identical crystalline phase of MnO2 crystals is essential to evaluate the relationship between electrochemical performances and morphologies for lithium-ion battery application. In this study, urchin-like α-MnO2 crystals with compact structure have better electrochemical performance due to the higher specific capacity and lower impedance. We find that the relationship between electrochemical performance and morphology is different when MnO2 material used as electrochemical supercapacitor or as anode of lithium-ion battery. For lithium-ion battery application, urchin-like MnO2 material has better electrochemical performance.

  14. Study of the Morphological, Structural and Photoelectrochemical Properties of TiO{sub 2} Nanorods grown by Hydrothermal Method

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hayoung; Ryu, Hyukhyun [Inje University, Gimhae (Korea, Republic of); Lee, Won-Jae [Dong-Eui University, Busan (Korea, Republic of)

    2017-01-15

    We investigated the effects of growth duration on the morphological, structural, and photoelectrochemical properties of TiO{sub 2} nanorods grown on a TiO{sub 2}-buffered fluorine-doped tin oxide (FTO) substrate using the hydrothermal method. From the study, we found that the photoelectrochemical properties were mainly dependent on the nanorod length and (002) XRD peak intensity, which indicates vertical growth of the TiO{sub 2}. The morphological and structural properties of the TiO{sub 2} nanorods largely affect their photoelectrochemical properties. The photocurrent density was increased when the growth duration was increased from 1 hour to 4 hours, and then changed little above 4 hours. Consequently, the highest photocurrent density, 0.897 mA/cm{sup 2} (at 1.0 V vs. SCE), was obtained from the 8 hour-sample which had good morphological and structural properties. We used field emission scanning electron microscopy (FE-SEM) for analysis of the morphological properties, x-ray diffraction (XRD) for structural properties, and three-electrode potentiostat for photoelectrochemical properties.

  15. Large-scale synthesis of double cauliflower-like Sb2S3 microcrystallines by hydrothermal method

    International Nuclear Information System (INIS)

    Wu, Lei; Xu, Hanyue; Han, Qiaofeng; Wang, Xin

    2013-01-01

    Highlights: •Highly uniform double cauliflower-like Sb 2 S 3 particles were synthesized via hydrothermal method. •Influence of reaction conditions on the morphology of the products was discussed. •Double cauliflower-like Sb 2 S 3 superstructures revealed broad spectrum response. -- Abstract: The double cauliflower-like Sb 2 S 3 superstructures assembled by nanorods were prepared using SbCl 3 and Na 2 S⋅9H 2 O as raw materials, dodecyltrimethylammonium bromide (DTAB, C 15 H 31 BrN) as surfactant under acidic condition at 180 °C for 30 h. The structure, morphology and composition of the product were characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and energy diffraction spectroscopy (EDS). The effect of reaction conditions including temperature, reaction time and surfactants on the sample morphology was discussed and a possible mechanism for the formation of cauliflower-like Sb 2 S 3 was proposed. The cauliflower-like Sb 2 S 3 microcrystallines revealed broad spectrum response, which may have a good application prospect in solar energy utilization and photoelectric conversion fields

  16. Self-Assembly of TiO2/CdS Mesoporous Microspheres with Enhanced Photocatalytic Activity via Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Sujing Yu

    2014-01-01

    Full Text Available Self assembly of TiO2/CdS mesoporous microspheres was synthesized via hydrothermal method. The samples were characterized by X-ray powder diffraction (XRD, ultraviolet-visible diffuse reflectance spectroscopy (DRS, transmission electron microscopy (TEM, energy-dispersive spectroscopy analysis (EDS, high-resolution transmission electron microscopy (HRTEM, Brunauer-Emmett-Teller (BET, X-ray photoelectron spectroscopy (XPS, and photoluminescence spectra (PL. The as-synthesized TiO2/CdS mesoporous microspheres showed superior photocatalytic activity for the degradation of RhB under either visible light or simulated sunlight irradiation; the 10 wt% TiO2/CdS sample showed the best performance. Moreover, this catalyst showed improved stability, and the activity did not decrease significantly after four recycles. The heterojunction between TiO2 and CdS may be favorable for the transport of photoinduced electrons from CdS to TiO2. In addition, the mesoporous structure could increase the utilization of light energy and facilitate the diffusion of reactants and products during the photocatalytic reaction.

  17. Facile hydrothermal synthesis of ultrasmall W{sub 18}O{sub 49} nanoparticles and studies of their photocatalytic activity towards degradation of methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, Bishal; Paul, Bappi [Department of Chemistry, National Institute of Technology, Silchar, Silchar, 788010, Assam (India); Dhar, Siddhartha Sankar, E-mail: ssd_iitg@hotmail.com [Department of Chemistry, National Institute of Technology, Silchar, Silchar, 788010, Assam (India); Vadivel, Sethumathavan [Department of Chemistry, PSG College of Technology, Coimbatore, Tamilnadu, 641004 (India)

    2017-02-15

    Uniformly dispersed ultrasmall tungsten oxide nanoparticles (W{sub 18}O{sub 49}) of sizes around 5–7 nm were synthesized using tungsten hexachloride as tungsten precursor and octadecylamine (ODA) as surfactant and as well as reducing agent. The as-synthesized nanoparticles (NPs) were characterized thoroughly by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) and N{sub 2} adsorption desorption isotherm (BET). From the XRD patterns, formation of monoclinic primitive phase of W{sub 18}O{sub 49} was observed while TEM images showed well dispersed particles of sizes 5–7 nm. The surface area of the W{sub 18}O{sub 49} NPs was found to be 27.17 m{sup 2} g{sup −1}. These ultrasmall W{sub 18}O{sub 49} NPs have been studied as photocatalysts for the first time in the degradation of methylene blue (MB). The photocatalytic activity was evaluated in oxidative degradation of MB with H{sub 2}O{sub 2} under solar irradiation. The particles exhibited pronounced activity in degradation of MB as well as efficient recyclability. The small band gap energy of W{sub 18}O{sub 49} NPs and their large surface area helps in the production of higher electron (e{sup −}) and hole (h{sup +}) pairs which in a way also prevents the e{sup −} and h{sup +} pairs from recombination within the nanoparticles. This greatly improves and enhances the photocatalytic activity of our synthesized nanoparticles. - Highlights: • Ultrasmall W{sub 18}O{sub 49} NPs were synthesized by a facile hydrothermal route. • Octadecylamine was used as both capping and reducing agent. • The XRD patterns revealed formation of monoclinic primitive phase of W{sub 18}O{sub 49}. • The TEM images showed that the material were well dispersed with sizes from 5 to 7 nm. • The synthesized NPs exhibited pronounced photocatalytic activity towards MB degradation.

  18. Hydrothermal synthesis and sol-gel methods for CdS particle production in different morphologies and their use in wastewater applications

    OpenAIRE

    Tuncer, Cansel

    2018-01-01

    In this study, CdSnanoparticles were synthesized in different sizes and morphologies using twodifferent methods. First, the synthesis of both cauliflower-type CdS microspheresand CdS nanoflower-type microstructures by hydrothermal synthesis was carriedout in a steel reactors with teflon chamber. While polyethylene glycol andthioacetamide were used in the synthesis of cauliflower-type CdS microspheres,thiourea was used as a sulfur source in the synthesis of nanoflower CdS microstructures.Spher...

  19. Linear facility location in three dimensions - Models and solution methods

    DEFF Research Database (Denmark)

    Brimberg, Jack; Juel, Henrik; Schöbel, Anita

    2002-01-01

    We consider the problem of locating a line or a line segment in three-dimensional space, such that the sum of distances from the facility represented by the line (segment) to a given set of points is minimized. An example is planning the drilling of a mine shaft, with access to ore deposits through...... horizontal tunnels connecting the deposits and the shaft. Various models of the problem are developed and analyzed, and efficient solution methods are given....

  20. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Hoffmann, Jessica

    2014-01-01

    Biomass is one of the most abundant sources of renewable energy, and will be an important part of a more sustainable future energy system. In addition to direct combustion, there is growing attention on conversion of biomass into liquid en-ergy carriers. These conversion methods are divided...... into biochemical/biotechnical methods and thermochemical methods; such as direct combustion, pyrolysis, gasification, liquefaction etc. This chapter will focus on hydrothermal liquefaction, where high pressures and intermediate temperatures together with the presence of water are used to convert biomass...... into liquid biofuels, with the aim of describing the current status and development challenges of the technology. During the hydrothermal liquefaction process, the biomass macromolecules are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive...

  1. Synthesis of anhydrous K2TiOF4 via a mild hydrothermal method

    Science.gov (United States)

    Felder, Justin B.; Yeon, Jeongho; zur Loye, Hans-Conrad

    2015-10-01

    The synthesis of anhydrous K2TiOF4 has been previously attempted by transforming precursor compounds, such as the peroxide (K2Ti(O2)F4), hydrate (K2TiOF4·H2O) and fluoride (K2TiF6). Due to the large structural differences between these precursors and the anhydrous oxyfluorides, however, these preparations have been unsuccessful. Therefore, a direct method of synthesis has been employed to grow single crystals of K2TiOF4 that were characterized by single crystal x-ray diffraction. K2TiOF4 was found to be isostructural with the previously known K2VOF4.

  2. Rapid Hydrothermal Synthesis of Zinc Oxide Nanowires by Annealing Methods on Seed Layers

    Directory of Open Access Journals (Sweden)

    Jang Bo Shim

    2011-01-01

    Full Text Available Well-aligned zinc oxide (ZnO nanowire arrays were successfully synthesized on a glass substrate using the rapid microwave heating process. The ZnO seed layers were produced by spinning the precursor solutions onto the substrate. Among coatings, the ZnO seed layers were annealed at 100°C for 5 minutes to ensure particle adhesion to the glass surface in air, nitrogen, and vacuum atmospheres. The annealing treatment of the ZnO seed layer was most important for achieving the high quality of ZnO nanowire arrays as ZnO seed nanoparticles of larger than 30 nm in diameter evolve into ZnO nanowire arrays. Transmission electron microscopy analysis revealed a single-crystalline lattice of the ZnO nanowires. Because of their low power (140 W, low operating temperatures (90°C, easy fabrication (variable microwave sintering system, and low cost (90% cost reduction compared with gas condensation methods, high quality ZnO nanowires created with the rapid microwave heating process show great promise for use in flexible solar cells and flexible display devices.

  3. Experimental facility and void fraction calibration methods for impedance probes

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Fernando L. de; Rocha, Marcelo S., E-mail: floliveira@ipen.br, E-mail: msrocha@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    An experimental facility was designed and constructed with aims of to calibrate a capacitance probe for gas-liquid flow void fraction measurements. The facility is composed of a metallic hack with a vertical 2,300 mm high glass tube with 38 mm ID with stagnant water and compressed air bubbling system simulating the gas phase (vapor). At the lower part, a mixing section with a porous media element releases the air bubbles into the water, and the compressed air flow is measured by two calibrated rotameters. At the upper part a stagnant water tank separates the liquid and gas. Two pressure taps are located near the lower and upper sides of the glass tube for pressure difference measurement. The pressure difference is used for low void fraction values (0-15%) calibration methods, as described in the work. Two electrically controlled quick closing valves are installed between the porous media element and the upward separation tank for high void fraction values measurement (15-50%) used to calibrate the capacitance probe. The experimental facility design, construction, capacitance probe calibration methods and results, as well as flow pattern visualization, are presented. Finally, the capacitance probe will be installed on a natural circulation circuit mounted at the Nuclear Engineering Center (CEN/IPEN/CNEN-SP) for measurement of the instantaneous bulk void. Instantaneous signals generated by the capacitance probe will allow the determination of natural circulation loop global energy balance. (author)

  4. Experimental facility and void fraction calibration methods for impedance probes

    International Nuclear Information System (INIS)

    Oliveira, Fernando L. de; Rocha, Marcelo S.

    2013-01-01

    An experimental facility was designed and constructed with aims of to calibrate a capacitance probe for gas-liquid flow void fraction measurements. The facility is composed of a metallic hack with a vertical 2,300 mm high glass tube with 38 mm ID with stagnant water and compressed air bubbling system simulating the gas phase (vapor). At the lower part, a mixing section with a porous media element releases the air bubbles into the water, and the compressed air flow is measured by two calibrated rotameters. At the upper part a stagnant water tank separates the liquid and gas. Two pressure taps are located near the lower and upper sides of the glass tube for pressure difference measurement. The pressure difference is used for low void fraction values (0-15%) calibration methods, as described in the work. Two electrically controlled quick closing valves are installed between the porous media element and the upward separation tank for high void fraction values measurement (15-50%) used to calibrate the capacitance probe. The experimental facility design, construction, capacitance probe calibration methods and results, as well as flow pattern visualization, are presented. Finally, the capacitance probe will be installed on a natural circulation circuit mounted at the Nuclear Engineering Center (CEN/IPEN/CNEN-SP) for measurement of the instantaneous bulk void. Instantaneous signals generated by the capacitance probe will allow the determination of natural circulation loop global energy balance. (author)

  5. Shape-control by microwave-assisted hydrothermal method for the synthesis of magnetite nanoparticles using organic additives

    Energy Technology Data Exchange (ETDEWEB)

    Rizzuti, Antonino [Politecnico di Bari, Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica (Italy); Dassisti, Michele [Politecnico di Bari, Dipartimento di Meccanica, Management e Matematica (Italy); Mastrorilli, Piero, E-mail: p.mastrorilli@poliba.it [Politecnico di Bari, Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica (Italy); Sportelli, Maria C.; Cioffi, Nicola; Picca, Rosaria A. [Università di Bari, Dipartimento di Chimica (Italy); Agostinelli, Elisabetta; Varvaro, Gaspare [Consiglio Nazionale delle Ricerche, Istituto di Struttura della Materia (Italy); Caliandro, Rocco [Consiglio Nazionale delle Ricerche, Istituto di Cristallografia (Italy)

    2015-10-15

    A simple and fast microwave-assisted hydrothermal method is proposed for the synthesis of magnetite nanoparticles. The addition of different surfactants (polyvinylpyrrolidone, oleic acid, or trisodium citrate) was studied to investigate the effect on size distribution, morphology, and functionalization of the magnetite nanoparticles. Microwave irradiation at 150 °C for 2 h of aqueous ferrous chloride and hydrazine without additives resulted in hexagonal magnetite nanoplatelets with a facet-to-facet distance of 116 nm and a thickness of 40 nm having a saturation magnetization of ∼65 Am{sup 2} kg{sup −1}. The use of polyvinylpyrrolidone led to hexagonal nanoparticles with a facet-to-facet distance of 120 nm and a thickness of 53 nm with a saturation magnetization of ∼54 Am{sup 2} kg{sup −1}. Additives such as oleic acid and trisodium citrate yielded quasi-spherical nanoparticles of 25 nm in size with a saturation magnetization of ∼70 Am{sup 2} kg{sup −1} and spheroidal nanoparticles of 60 nm in size with a saturation magnetization up to ∼82 Am{sup 2} kg{sup −1}, respectively. A kinetic control of the crystal growth is believed to be responsible for the hexagonal habit of the nanoparticles obtained without additive. Conversely, a thermodynamic control of the crystal growth, leading to spheroidal nanoparticles, seems to occur when additives which strongly interact with the nanoparticle surface are used. A thorough characterization of the materials was performed. Magnetic properties were investigated by Superconducting Quantum Interference Device and Vibrating Sample magnetometers. Based on the observed magnetic properties, the magnetite obtained using citrate appears to be a promising support for magnetically transportable catalysts.

  6. Rapid synthesis of Ti-MCM-41 by microwave-assisted hydrothermal method towards photocatalytic degradation of oxytetracycline.

    Science.gov (United States)

    Chen, Hanlin; Peng, Yen-Ping; Chen, Ku-Fan; Lai, Chia-Hsiang; Lin, Yung-Chang

    2016-06-01

    This study employed microwave-assisted hydrothermal method to synthesize Ti-MCM-41, which are mesoporous materials with a high surface area and excellent photocatalytic ability. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy (UV-Vis) were employed. The XRD findings showed that Ti-MCM-41 exhibited a peak at 2θ of 2.2°, which was attributed to the hexagonal MCM-41 structure. The BET (Brunauer-Emmett-Teller) results agreed with the TEM findings that Ti-MCM-41 has a pore size of about 3-5nm and a high surface area of 883m(2)/g. FTIR results illustrated the existence of Si-O-Si and Si-O-Ti bonds in Ti-MCM-41. The appearance of Ti 2p peaks in the XPS results confirmed the FTIR findings that the Ti was successfully doped into the MCM-41 structure. Zeta (ζ)-potential results indicated that the iso-electric point (IEP) of Ti-MCM-41 was at about pH3.02. In this study, the photocatalytic degradation of oxytetracycline (OTC) at different pH was investigated under Hg lamp irradiation (wavelength 365nm). The rate constant (K'obs) for OTC degradation was 0.012min(-1) at pH3. Furthermore, TOC (total organic carbon) and high resolution LC-MS (liquid chromatography-mass spectrometry) analyses were conducted to elucidate the possible intermediate products and degradation pathway for OTC. The TOC removal efficiency of OTC degradation was 87.0%, 74.4% and 50.9% at pH3, 7 and 10, respectively. LC-MS analysis results showed that the degradation products from OTC resulted from the removal of functional groups from the OTC ring. Copyright © 2016. Published by Elsevier B.V.

  7. Influence of External Gaseous Environments on the Electrical Properties of ZnO Nanostructures Obtained by a Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Marcin Procek

    2016-11-01

    Full Text Available This paper deals with experimental investigations of ZnO nanostructures, consisting of a mixture of nanoparticles and nanowires, obtained by the chemical (hydrothermal method. The influences of both oxidizing (NO2 and reducing gases (H2, NH3, as well as relative humidity (RH on the physical and chemical properties of ZnO nanostructures were tested. Carrier gas effect on the structure interaction with gases was also tested; experiments were conducted in air and nitrogen (N2 atmospheres. The effect of investigated gases on the resistance of the ZnO nanostructures was tested over a wide range of concentrations at room temperature (RT and at 200 °C. The impact of near- ultraviolet (UV excitation (λ = 390 nm at RT was also studied. These investigations indicated a high response of ZnO nanostructures to small concentrations of NO2. The structure responses to 1 ppm of NO2 amounted to about: 600% in N2/230% in air at 200 °C (in dark conditions and 430% in N2/340% in air at RT (with UV excitation. The response of the structure to the effect of NO2 at 200 °C is more than 105 times greater than the response to NH3, and more than 106 times greater than that to H2 in the relation of 1 ppm. Thus the selectivity of the structure for NO2 is very good. What is more, the selectivity to NO2 at RT with UV excitation increases in comparison at elevated temperature. This paper presents a great potential for practical applications of ZnO nanostructures (including nanoparticles in resistive NO2 sensors.

  8. Ultrasonic vs hydrothermal method: Different approaches to convert fly ash into zeolite. How they affect the stability of synthetic products over time?

    Science.gov (United States)

    Belviso, Claudia

    2018-05-01

    The action of direct sonication (US) versus conventional hydrothermal method (HY) was investigated to determine the differences in the crystallization mechanism of zeolite formed from fly ash. The results showed that ultrasonic energy is decisive in very fast faujasite and A-type zeolite transformation into more stable sodalite phase. The data display the main presence of sodalite together with a low amount of faujasite and zeolite A after the first 3 h of sonication. The full transformation of the latter two phases into sodalite takes place after 1 h more of treatment. The samples incubated by hydrothermal process for 3 h, instead, are characterized by the main presence of faujasite and A-type zeolites. The progressive synthesis of sodalite at the expense of the other two phases begins only after 4 h of treatment. The conclusion is that the crystallization of zeolites by ultrasonic and hydrothermal method proceeds via two different mechanisms. The data also show that the two approaches affect the stability of the synthetic products in a different way over the years. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. An integrated approach for facilities planning by ELECTRE method

    Science.gov (United States)

    Elbishari, E. M. Y.; Hazza, M. H. F. Al; Adesta, E. Y. T.; Rahman, Nur Salihah Binti Abdul

    2018-01-01

    Facility planning is concerned with the design, layout, and accommodation of people, machines and activities of a system. Most of the researchers try to investigate the production area layout and the related facilities. However, few of them try to investigate the relationship between the production space and its relationship with service departments. The aim of this research to is to integrate different approaches in order to evaluate, analyse and select the best facilities planning method that able to explain the relationship between the production area and other supporting departments and its effect on human efforts. To achieve the objective of this research two different approaches have been integrated: Apple’s layout procedure as one of the effective tools in planning factories, ELECTRE method as one of the Multi Criteria Decision Making methods (MCDM) to minimize the risk of getting poor facilities planning. Dalia industries have been selected as a case study to implement our integration the factory have been divided two main different area: the whole facility (layout A), and the manufacturing area (layout B). This article will be concerned with the manufacturing area layout (Layout B). After analysing the data gathered, the manufacturing area was divided into 10 activities. There are five factors that the alternative were compared upon which are: Inter department satisfactory level, total distance travelled for workers, total distance travelled for the product, total time travelled for the workers, and total time travelled for the product. Three different layout alternatives have been developed in addition to the original layouts. Apple’s layout procedure was used to study and evaluate the different alternatives layouts, the study and evaluation of the layouts was done by calculating scores for each of the factors. After obtaining the scores from evaluating the layouts, ELECTRE method was used to compare the proposed alternatives with each other and with

  10. Hydrothermal Treatment (HTT) of Microalgae: Evaluation of the Process As Conversion Method in an Algae Biorefinery Concept

    NARCIS (Netherlands)

    Garcia Alba, Laura; Torri, C.; Samori, C.; van der Spek, J.J.; Fabbri, D.; Kersten, Sascha R.A.; Brilman, Derk Willem Frederik

    2012-01-01

    The hydrothermal treatment (HTT) technology is evaluated for its potential as a process to convert algae and algal debris into a liquid fuel, within a sustainable algae biorefinery concept in which, next to fuels (gaseous and liquid), high value products are coproduced, nutrients and water are

  11. A proactive method for safety management in nuclear facilities

    International Nuclear Information System (INIS)

    Grecco, Claudio Henrique dos Santos; Carvalho, Paulo Victor Rodrigues de; Santos, Isaac Antonio Luquetti dos

    2014-01-01

    Due to the modern approach to address the safety of nuclear facilities which highlights that these organizations must be able to assess and proactively manage their activities becomes increasingly important the need for instruments to evaluate working conditions. In this context, this work presents a proactive method of managing organizational safety, which has three innovative features: 1) the use of predictive indicators that provide current information on the performance of activities, allowing preventive actions and not just reactive in safety management, different from safety indicators traditionally used (reactive indicators) that are obtained after the occurrence of undesired events; 2) the adoption of resilience engineering approach in the development of indicators - indicators are based on six principles of resilience engineering: top management commitment, learning, flexibility, awareness, culture of justice and preparation for the problems; 3) the adoption of the concepts and properties of fuzzy set theory to deal with subjectivity and consistency of human trials in the evaluation of the indicators. The fuzzy theory is used primarily to map qualitative models of decision-making, and inaccurate representation methods. The results of this study aim an improvement in performance and safety in organizations. The method was applied in a radiopharmaceutical shipping sector of a nuclear facility. The results showed that the method is a good monitoring tool objectively and proactively of the working conditions of an organizational domain

  12. Argentine hydrothermal panorama

    Energy Technology Data Exchange (ETDEWEB)

    1976-12-01

    An attempt is made to give a realistic review of Argentine thermal waters. The topics discussed are the characteristics of the hydrothermal resources, classification according to their mineral content, hydrothermal flora and fauna, uses of hydrothermal resources, hydrothermal regions of Argentina, and meteorology and climate. A tabulation is presented of the principal thermal waters. (JSR)

  13. Microstructure and magnetic properties of MFe{sub 2}O{sub 4} (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei, E-mail: wangwei@mail.buct.edu.cn; Ding, Zui; Zhao, Xiruo [State Key Laboratory of Chemical Resource Engineering and School of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Beijing Key Laboratory of Environmentally Harmful Chemical Analysis, Beijing University of Chemical Technology, Beijing 100029 (China); Wu, Sizhu [State Key Laboratory of Organic–Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Li, Feng [State Key Laboratory of Chemical Resource Engineering and School of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Yue, Ming [College of Materials Science and Engineering, Beijing University of Technology, Beijing 100022 (China); Liu, J. Ping [Department of Physics, University of Texas at Arlington, Arlington, Texas 76019 (United States)

    2015-05-07

    Three kinds of spinel ferrite nanocrystals, MFe{sub 2}O{sub 4} (M = Co, Ni, and Mn), are synthesized using colloid mill and hydrothermal method. During the synthesis process, a rapid mixing and reduction of cations with sodium borohydride (NaBH{sub 4}) take place in a colloid mill then through a hydrothermal reaction, a slow oxidation and structural transformation of the spinel ferrite nanocrystals occur. The phase purity and crystal lattice parameters are estimated by X-ray diffraction studies. Scanning electron microscopy and transmission electron microscopy images show the morphology and particle size of the as-synthesized ferrite nanocrystals. Raman spectrum reveals active phonon modes at room temperature, and a shifting of the modes implies cation redistribution in the tetrahedral and octahedral sites. Magnetic measurements show that all the obtained samples exhibit higher saturation magnetization (M{sub s}). Meanwhile, experiments demonstrate that the hydrothermal reaction time has significant effects on microstructure, morphologies, and magnetic properties of the as-synthesized ferrite nanocrystals.

  14. The Scottish Structural Proteomics Facility: targets, methods and outputs

    DEFF Research Database (Denmark)

    Oke, Muse; Carter, Lester G; Johnson, Kenneth A

    2010-01-01

    The Scottish Structural Proteomics Facility was funded to develop a laboratory scale approach to high throughput structure determination. The effort was successful in that over 40 structures were determined. These structures and the methods harnessed to obtain them are reported here. This report...... reflects on the value of automation but also on the continued requirement for a high degree of scientific and technical expertise. The efficiency of the process poses challenges to the current paradigm of structural analysis and publication. In the 5 year period we published ten peer-reviewed papers...

  15. Optical and Morphological Properties of ZnO- and TiO2-Derived Nanostructures Synthesized via a Microwave-Assisted Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Nosipho Moloto

    2012-01-01

    Full Text Available A microwave-assisted hydrothermal method was used to synthesize ZnO and TiO2 nanostructures. The experimental results show that the method resulted in crystalline monodispersed ZnO nanorods that have pointed tips with hexagonal crystal phase. TiO2 nanotubes were also formed with minimum bundles. The mechanism for the formation of the tubes was validated by HRTEM results. The optical properties of both ZnO and TiO2 nanostructures showed characteristics of strong quantum confinement regime. The photoluminescence spectrum of TiO2 nanotubes shows good improvement from previously reported data.

  16. Synthesis and in-depth analysis of highly ordered yttrium doped hydroxyapatite nanorods prepared by hydrothermal method and its mechanical analysis

    International Nuclear Information System (INIS)

    Nathanael, A. Joseph; Mangalaraj, D.; Hong, S.I.; Masuda, Y.

    2011-01-01

    In this study, undoped and yttrium (Y) doped nanocrystalline hydroxyapatite crystals were synthesized by the hydrothermal method at 180 °C for 24 h. Highly ordered and oriented hydroxyapatite (HAp) nanorods were prepared by yttrium doping and their nanostructure and physical properties were compared with those of undoped HAp rods. FESEM images showed that the doping with Y ions reduced the diameter (from 25 nm to 15 nm) and increased the length (from 95 nm to 115 nm) of the synthesized rods. The aspect ratio of the undoped and Y-doped nanorods were calculated to be 4.303 (SD = 0.0959) and 7.61 (SD = 0.0355), respectively. Specific surface area (SSA) analysis showed that SSA also increased from 66.74 m 2 /g to 68.57 m 2 /g with the addition of yttrium. Y-doped HAp nanorod reinforced HMWPE composites displayed the better mechanical performance than those reinforced with pure HAp nanorods. The possible strengthening of nanorods and the increase of SSA due to the reduction in the size of nanorods in the presence of yttrium may have contributed to the strengthening of Y-doped HAp/HMWPE composites. - Graphical Abstract: Highly ordered and oriented yttrium doped hydroxyapatite (HAp) nanorods were prepared by hydrothermal method. For undoped HAp the average length of the nanorod is 95 nm with mean diameter of 24 nm and for a Y doped nanorod the average length is ∼ 115 nm and the mean diameter is 15 nm. Mechanical analysis was carried out by polymer/nanoparticle composite method. Highlights: ► Yttrium doped hydroxyapatite nanorods were prepared by hydrothermal method. ► The nanorods have highly uniform size distribution. ► Yttrium substitution and nanostructure formation was confirmed by careful analysis. ► Mechanical strength was analyzed by polymer nanoparticle reinforcement method.

  17. Preparation of flower-like CdS with SDBS as surfactant by hydrothermal method and its optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yongqian, E-mail: cugwyq@126.com [Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Yang, Xiande; Ma, Qun; Kong, Junhan; Jia, Hanxiang; Wang, Zhengshu [Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Yu, Meihua [School of Materials Science and Engineering, Guangxi University, Nanning 530004 (China)

    2015-06-15

    Graphical abstract: FESEM image of the CdS obtained by 0.01 mol Cd(NO{sub 3}){sub 2}·4H{sub 2}O, 0.03 mol thiourea and 0.5 g SDBS at 160 °C for 24 h. - Highlights: • The role of SDBS is to assemble CdS crystals together to form flower-like structures. • Both reaction time and temperature affect the morphology of flower-like structures. • The growth mechanism of flower-like structures is reasonable, clear and concise. • Its optical energy band gap is 2.50 eV, and it has absorption in visible region. • PL result of flower-like structures shows the max emission wavelength is 508.6 nm. - Abstract: In this article, the flower-like CdS have been prepared by hydrothermal method with thiourea as sulfur source and SDBS as surfactant. The effects of different experimental conditions on the morphology of CdS have been investigated. The performances of CdS have been analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), room temperature photoluminescence (PL) and UV–vis. The result of XRD indicates that CdS we prepared are highly crystallized, which are of hexagonal phase. The FE-SEM results indicate that the main role of SDBS is to make the CdS crystals assemble together to form the flower-like structures, and the reaction time affects the morphology of CdS, and the suitable reaction temperature is 160 °C. Its optical energy band gap is observed at 2.50 eV. The fluorescence spectrum shows that the flower-like CdS have a broad absorption peak and the max emission wavelength is 508.6 nm. The growth mechanism for the formation of CdS with flower-like structures is also described.

  18. Analytical methods and laboratory facility for the Defense Waste Processing Facility

    International Nuclear Information System (INIS)

    Coleman, C.J.; Dewberry, R.A.; Lethco, A.J.; Denard, C.D.

    1985-01-01

    This paper describes the analytical methods, instruments, and laboratory that will support vitrification of defense waste. The Defense Waste Processing Facility (DWPF) is now being constructed at Savannah River Plant (SRP). Beginning in 1989, SRP high-level defense waste will be immobilized in borosilicate glass for disposal in a federal repository. The DWPF will contain an analytical laboratory for performing process control analyses. Additional analyses will be performed for process history and process diagnostics. The DWPF analytical facility will consist of a large shielded sampling cell, three shielded analytical cells, a laboratory for instrumental analysis and chemical separations, and a counting room. Special instrumentation is being designed for use in the analytical cells, including microwave drying/dissolution apparatus, and remote pipetting devices. The instrumentation laboratory will contain inductively coupled plasma, atomic absorption, Moessbauer spectrometers, a carbon analyzer, and ion chromatography equipment. Counting equipment will include intrinsic germanium detectors, scintillation counters, Phoswich alpha, beta, gamma detectors, and a low-energy photon detector

  19. Hydrothermal processing of actinide contaminated organic wastes

    International Nuclear Information System (INIS)

    Worl, A.; Buelow, S.J.; Le, L.A.; Padilla, D.D.; Roberts, J.H.

    1997-01-01

    Hydrothermal oxidation is an innovative process for the destruction of organic wastes, that occurs above the critical temperature and pressure of water. The process provides high destruction and removal efficiencies for a wide variety of organic and hazardous substances. For aqueous/organic mixtures, organic materials, and pure organic liquids hydrothermal processing removes most of the organic and nitrate components (>99.999%) and facilitates the collection and separation of the actinides. We have designed, built and tested a hydrothermal processing unit for the removal of the organic and hazardous substances from actinide contaminated liquids and solids. Here we present results for the organic generated at the Los Alamos National Laboratory Plutonium Facility

  20. Optical and morphological properties of ZnO- and TiO2-derived nanostructures synthesized via a microwave-assisted hydrothermal method

    CSIR Research Space (South Africa)

    Moloto, N

    2012-01-01

    Full Text Available Corporation International Journal of Photoenergy Volume 2012, Article ID 189069, 6 pages doi:10.1155/2012/189069 Research Article Optical and Morphological Properties of ZnO- and TiO2-Derived Nanostructures Synthesized via a Microwave... International Journal of Photoenergy the sol-gel, hydrothermal process, and pulse laser deposition [22?24]. Although the sol-gel method is widely accepted for the preparation of both ZnO and TiO2 nanostructures, the calcinations process is essential and can...

  1. Method of preventing contaminations in radioactive material handling facilities

    International Nuclear Information System (INIS)

    Inoue, Shunji.

    1986-01-01

    Purpose: To prevent the contamination on the floor surface of working places by laying polyvinyl butyral sheets over the floor surface, replacing when the sheets are contaminated, followed by burning. Method: Polyvinyl butyral sheets comprising 50 - 70 mol% of butyral component are laid in a radioactive material handling facility, radioactive materials are handled on the polyvinyl butyral sheets and the sheets are replaced when contaminated. The polyvinyl butyral sheets used contain 62 - 68 mol% of butyral component and has 0.03 - 0.2 mm thickness. The contaminated sheets are subjected to burning processing. This can surely collect radioactive materials and the sheets have favorable burnability, releasing no corrosive or deleterious gases. In addition, they are inexpensive and give no hindrance to the workers walking. (Takahashi, M.)

  2. A facile method to fabricate superhydrophobic cotton fabrics

    Science.gov (United States)

    Zhang, Ming; Wang, Shuliang; Wang, Chengyu; Li, Jian

    2012-11-01

    A facile and novel method for fabricating superhydrophobic cotton fabrics is described in the present work. The superhydrophobic surface has been prepared by utilizing cationic poly (dimethyldiallylammonium chloride) and silica particles together with subsequent modification of (heptadecafluoro-1,1,2,2-tetradecyl) trimethoxysilane. The size distribution of silica particles was measured by Particle Size Analyzer. The cotton textiles before and after treatment were characterized by using scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The wetting behavior of cotton samples was investigated by water contact angle measurement. Moreover, the superhydrophobic durability of coated cotton textiles has been evaluated by exposure, immersion and washing tests. The results show that the treated cotton fabrics exhibited excellent chemical stability and outstanding non-wettability with the WCA of 155 ± 2°, which offers an opportunity to accelerate the large-scale production of superhydrophobic textiles materials for new industrial applications.

  3. A Comparative Characterization of the HPA-MCM-48 Type Catalysts Produced by the Direct Hydrothermal and Room Temperature Synthesis Methods

    International Nuclear Information System (INIS)

    Gucbilmez, Y.; Calis, I.; Yargic, A. S.

    2012-01-01

    MCM-48 type support materials synthesized by the direct hydrothermal synthesis (HTS) and room temperature synthesis (RTS) methods were incorporated with tungstophosphoric acid (TPA) in the range of 10-40 wt% by using a wet impregnation technique in methanol solutions. Resulting HPA-MCM-48 catalysts were characterized by the XRD, Nitrogen Physisorption, SEM, TEM, EDS, and FT-IR methods in order to determine the effects of different initial synthesis conditions on the catalyst properties. RTS samples were found to have better crystalline structures, higher BET surface areas, and higher BJH pore volumes than HTS samples. They also had slightly higher TPA incorporation, except for the 40 wt% samples, as evidenced by the EDS results. Keggin ion structure was preserved, for both methods, even at the highest acid loading of 40 wt%. It was concluded that the simpler and more economical RTS method was more successful than the HTS method for hetero poly acid incorporation into MCM-48 type materials

  4. Methods for expanding the capacity of spent fuel storage facilities

    International Nuclear Information System (INIS)

    1990-06-01

    At the beginning of 1989 more than 55,000 metric tonnes of heavy metal (MTHM) of spent Light Water Reactor (LWR) and Heavy Water Reactor (HWR) fuel had been discharged worldwide from nuclear power plants. Only a small fraction of this fuel has been reprocessed. The majority of the spent fuel assemblies are currently held at-reactor (AR) or away-from-reactor (AFR) in storage awaiting either chemical processing or final disposal depending on the fuel concept chosen by individual countries. Studies made by NEA and IAEA have projected that annual spent fuel arising will reach about 10,000 t HM in the year 2000 and cumulative arising will be more than 200,000 t HM. Taking into account the large quantity of spent fuel discharged from NPP and that the first demonstrations of the direct disposal of spent fuel or HLW are expected only after the year 2020, long-term storage will be the primary option for management of spent fuel until well into the next century. There are several options to expand storage capacity: (1) to construct new away-from-reactor storage facilities, (2) to transport spent fuel from a full at-reactor pool to another site for storage in a pool that has sufficient space to accommodate it, (3) to expand the capacity of existing AR pools by using compact racks, double-tierce, rod consolidation and by increasing the dimensions of existing pools. The purpose of the meeting was: to exchange new information on the international level on the subject connected with the expansion of storage capacities for spent fuel; to elaborate the state-of-the-art of this problem; to define the most important areas for future activity; on the basis of the above information to give recommendations to potential users for selection and application of the most suitable methods for expanding spent fuel facilities taking into account the relevant country's conditions. Refs, figs and tabs

  5. Non-enzymatic hydrogen peroxide biosensor based on rose-shaped FeMoO4 nanostructures produced by convenient microwave-hydrothermal method

    International Nuclear Information System (INIS)

    Liu, Hongying; Gu, Chunchuan; Li, Dujuan; Zhang, Mingzhen

    2015-01-01

    Graphical abstract: A non-enzymatic H 2 O 2 sensor with high selectivity and sensitivity based on rose-shaped FeMoO 4 synthesized by the convenient microwave-assisted hydrothermal method, was fabricated. - Highlights: • Rose-shaped FeMoO 4 is synthesized within 10 min via microwave-assisted hydrothermal approach. • Non-enzymatic hydrogen peroxide biosensor based on FeMoO 4 nanomaterials is fabricated. • The biosensor exhibits good performance. - Abstract: In this work, we demonstrated a simple, rapid and reliable microwave-assisted hydrothermal approach to synthesize the uniform rose-shaped FeMoO 4 within 10 min. The morphologies of the synthesized materials were characterized by X-ray powder diffraction and scanning electron microscopy. Moreover, a non-enzymatic amperometric sensor for the detection of hydrogen peroxide (H 2 O 2 ) was fabricated on the basis of the FeMoO 4 as electrocatalysis. The resulting FeMoO 4 exhibited high sensitivity and good stability for the detection of H 2 O 2 , which may be attributed to the rose-shaped structure of the material and the catalytic property of FeMoO 4 . Amperometric response showed that the modified electrode had a good response for H 2 O 2 with a linear range from 1 μM to 1.6 mM, a detection limit of 0.5 μM (S/N = 3), high selectivity and short response time. Additionally, good recoveries of analytes in real milk samples confirm the reliability of the prepared sensor in practical applications

  6. Non-enzymatic hydrogen peroxide biosensor based on rose-shaped FeMoO{sub 4} nanostructures produced by convenient microwave-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongying, E-mail: liuhongying@hdu.edu.cn [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Zhejiang, Hangzhou 310018 (China); Gu, Chunchuan [Department of Clinical Laboratory, Hangzhou Cancer Hospital, Zhejiang, Hangzhou 310002 (China); Li, Dujuan; Zhang, Mingzhen [College of Life Information Science & Instrument Engineering, Hangzhou Dianzi University, Zhejiang, Hangzhou 310018 (China)

    2015-04-15

    Graphical abstract: A non-enzymatic H{sub 2}O{sub 2} sensor with high selectivity and sensitivity based on rose-shaped FeMoO{sub 4} synthesized by the convenient microwave-assisted hydrothermal method, was fabricated. - Highlights: • Rose-shaped FeMoO{sub 4} is synthesized within 10 min via microwave-assisted hydrothermal approach. • Non-enzymatic hydrogen peroxide biosensor based on FeMoO{sub 4} nanomaterials is fabricated. • The biosensor exhibits good performance. - Abstract: In this work, we demonstrated a simple, rapid and reliable microwave-assisted hydrothermal approach to synthesize the uniform rose-shaped FeMoO{sub 4} within 10 min. The morphologies of the synthesized materials were characterized by X-ray powder diffraction and scanning electron microscopy. Moreover, a non-enzymatic amperometric sensor for the detection of hydrogen peroxide (H{sub 2}O{sub 2}) was fabricated on the basis of the FeMoO{sub 4} as electrocatalysis. The resulting FeMoO{sub 4} exhibited high sensitivity and good stability for the detection of H{sub 2}O{sub 2}, which may be attributed to the rose-shaped structure of the material and the catalytic property of FeMoO{sub 4}. Amperometric response showed that the modified electrode had a good response for H{sub 2}O{sub 2} with a linear range from 1 μM to 1.6 mM, a detection limit of 0.5 μM (S/N = 3), high selectivity and short response time. Additionally, good recoveries of analytes in real milk samples confirm the reliability of the prepared sensor in practical applications.

  7. Synthesis of metal-doped Mn-Zn ferrite from the leaching solutions of vanadium slag using hydrothermal method

    Science.gov (United States)

    Liu, Shiyuan; Wang, Lijun; Chou, Kuochih

    2018-03-01

    Using vanadium slag as raw material, Metal-doped Mn-Zn ferrites were synthesized by multi-step processes including chlorination of iron and manganese by NH4Cl, selective oxidation of Fe cation, and hydrothermal synthesis. The phase composition and magnetic properties of synthesized metal-doped Mn-Zn ferrite were characterized by X-ray powder diffraction, Raman spectroscopy, transmission electron microscopy (TEM), X-ray photon spectra (XPS) and physical property measurement. It was found that Mn/Zn mole ratio significantly affected the magnetic properties and ZnCl2 content significantly influenced the purity of the phase of ferrite. Synthesized metal-doped Mn-Zn ferrite, exhibiting a larger saturation magnetization (Ms = 60.01 emu/g) and lower coercivity (Hc = 8.9 Oe), was obtained when the hydrothermal temperature was controlled at 200 °C for 12 h with a Mn/Zn mole ratio of 4. The effect of ZnCl2 content, Mn/Zn mole ratio and temperature on magnetic properties of the synthesized metal-doped Mn-Zn ferrite were systemically investigated. This process provided a new insight to utilize resources in the aim of obtaining functional materials.

  8. Hydrothermal treatment and enzymatic hydrolysis of Tamarix ramosissima: evaluation of the process as a conversion method in a biorefinery concept.

    Science.gov (United States)

    Xiao, Ling-Ping; Shi, Zheng-Jun; Xu, Feng; Sun, Run-Cang

    2013-05-01

    The present work investigated the effects of hydrothermal treatment (HTT) of Tamarix ramosissima by determination of sugar and inhibitor formation in the liquid fraction, and chemical and morphological changes of the pretreated solid material coupled with an evaluation of enzymatic hydrolysis. HTT was carried out in a batch reactor system at a maximal temperature (TMAX 180-240 °C) and evaluated for severities logRo ranging from 2.40 to 4.17. The liquid fractions were analyzed by HPLC, GPC, and GC-MS. The morphology and composition of the solid residues were characterized using an array of techniques, such as SEM, XRD, BET surface area, and CP/MAS (13)C NMR. Using a variety of tools, we have developed a better understanding of how HTT process affects biomass structure and cellulose properties that impact on its digestibility. These results provided new insights into the factors limiting enzymatic digestibility and mechanism of biomass deconstruction during hydrothermal process. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  9. Polarization reversal in BaTiO{sub 3} nanostructures synthesized by microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Velasco-Davalos, Ivan; Ambriz-Vargas, Fabian [Centre Énergie, Matériaux et Télécommunications, INRS, 1650 Lionel-Boulet, Varennes, Québec J3X1S2 (Canada); Gómez-Yáñez, Carlos [Departamento de Ingeniería en Metalurgia y Materiales, ESIQIE, Instituto Politécnico Nacional, UPALM, Zacatenco, CP 07738 DF, México (Mexico); Thomas, Reji, E-mail: reji.thomas@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650 Lionel-Boulet, Varennes, Québec J3X1S2 (Canada); Ruediger, Andreas, E-mail: ruediger@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650 Lionel-Boulet, Varennes, Québec J3X1S2 (Canada)

    2016-05-15

    Ferroelectric BaTiO{sub 3} nanostructures and thin films were deposited by a microwave assisted hydrothermal process at low temperatures (<250 °C) on metallic Pt/Al{sub 2}O{sub 3}/SiO{sub 2}/Si and Nb:SrTiO{sub 3} (100) substrates. TiO{sub 2} nanoparticles dispersed in the Ba(OH){sub 2} alkaline solution are used as the precursors without any mineralizers. The incorporation of H{sub 2}O{sub 2} into precursor solution served as a strong oxidant and catalyst for the uniform nucleation of BaTiO{sub 3} on the substrate surface. The polycrystalline and epitaxial nature of the films were confirmed by atomic force microscopy and x-ray diffraction studies. We report the ferroelectric behavior of BaTiO{sub 3} films on Nb:SrTiO{sub 3} (100) substrates by piezoresponse force microscopy. - Highlights: • Microwave assisted hydrothermal deposition of highly ordered BaTiO{sub 3} thin films on single crystal substrates. • Fast growth without the needof any mineralizers. • Moderate addition of H{sub 2}O{sub 2} significantly improves the surface coverage. • H{sub 2}O{sub 2} substantially reduces hydrogen incorporation into the film and the associated leakage current. • Out-of-plane polarization reversal demonstrated locally.

  10. MoS{sub 2}–GO nanocomposites synthesized via a hydrothermal hydrogel method for solar light photocatalytic degradation of methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yong; Zhou, Yifeng, E-mail: yifengzhou@126.com; Nie, Wangyan; Chen, Pengpeng, E-mail: chenpp@ahu.edu.cn

    2015-12-01

    Graphical abstract: - Highlights: • The molybdenum disulfide–graphene oxide (MoS{sub 2}–GO) nanocomposite was synthesized via a one-step hydrothermal hydrogel method. • MoS{sub 2} and GO were composited fairly well in the obtained nanocomposites. • The electrons–hole pair recombination rate of MoS{sub 2} was greatly reduced via compositing with graphene. • The MoS{sub 2}–GO nanocomposite exhibited excellent photocatalytic performance for the degradation of methylene blue under solar light irradiation. - Abstract: In this work, molybdenum disulfide–graphene oxide (MoS{sub 2}–GO) composite hydrogel was prepared via a one-step hydrothermal method. The morphology and structure of the as-prepared hydrogels with different proportions of MoS{sub 2} and GO were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, electrochemical impedance spectra and UV–vis absorption spectroscopy. The photocatalytic performance of MoS{sub 2}–GO nanocomposites was studied toward the degradation of methylene blue (MB). Results showed that the MoS{sub 2}–GO nanocomposites exhibited improved photocatalytic activities in the degradation of MB with a maximum degradation rate of 99% under solar lights irradiation within 60 min. The synthesized MoS{sub 2}–GO composite hydrogel possesses great potential toward the development of newly synthesizable catalysts in the field of organic degradation in water.

  11. Influence of aluminum addition in the framework of MCM-41 mesoporous molecular sieve synthesized by non-hydrothermal method in an alkali-free system

    Energy Technology Data Exchange (ETDEWEB)

    La-Salvia, Nathália; Lovón-Quintana, Juan José; Lovón, Adriana Siviero Pagani; Valença, Gustavo Paim, E-mail: nathalialasalvia@gmail.com [Laboratório para o Estudo de Processos de Adsorção e Catálise - LEPAC, Faculdade de Engenharia Química, Universidade Estadual de Campinas - UNICAMP, Campinas, SP (Brazil)

    2017-11-15

    Purely siliceous MCM-41 and Al-containing MCM-41 (Al-MCM-41) mesoporous materials were synthesized by non-hydrothermal method in alkali-free ions medium at room temperature and short reaction times. Under these synthesis conditions, it was also investigated the influence of Al incorporation in the crystal structure of MCM-41. The solids were characterized by ICP-OES, AAS, N{sub 2} adsorption at 77 K, XRD, TEM, NH3 -TPD, {sup 27}Al and {sup 29}Si-MAS-NMR, FT-IR and TGA. The resulting mesoporous materials showed a well-defined hexagonally ordered pore geometry maintaining a uniform and unimodal pore size distribution with high specific surface areas (1000-1400 m{sup 2} g{sup -1}). The Al{sup +3} ions were introduced successfully in the structure of the purely siliceous MCM-41 expanding the unit cell parameter and forming four-coordinated Al species, and in a less extent, forming six-coordinated Al species. In addition, the surface acidity of the MCM-41 increased with Al loading. Contrary, the presence of Al in the MCM-41 mesoporous structure resulted in a decrease of the crystallinity and specific surface area possibly due to the presence of Al species in highly distorted tetrahedral structures and Al extra-framework or amorphous alumina occluded in the pores. The MCM-41 type mesoporous materials obtained in this work show similar characteristics of those synthesized by conventional hydrothermal methods. (author)

  12. Influence of aluminum addition in the framework of MCM-41 mesoporous molecular sieve synthesized by non-hydrothermal method in an alkali-free system

    International Nuclear Information System (INIS)

    La-Salvia, Nathália; Lovón-Quintana, Juan José; Lovón, Adriana Siviero Pagani; Valença, Gustavo Paim

    2017-01-01

    Purely siliceous MCM-41 and Al-containing MCM-41 (Al-MCM-41) mesoporous materials were synthesized by non-hydrothermal method in alkali-free ions medium at room temperature and short reaction times. Under these synthesis conditions, it was also investigated the influence of Al incorporation in the crystal structure of MCM-41. The solids were characterized by ICP-OES, AAS, N 2 adsorption at 77 K, XRD, TEM, NH3 -TPD, 27 Al and 29 Si-MAS-NMR, FT-IR and TGA. The resulting mesoporous materials showed a well-defined hexagonally ordered pore geometry maintaining a uniform and unimodal pore size distribution with high specific surface areas (1000-1400 m 2 g -1 ). The Al +3 ions were introduced successfully in the structure of the purely siliceous MCM-41 expanding the unit cell parameter and forming four-coordinated Al species, and in a less extent, forming six-coordinated Al species. In addition, the surface acidity of the MCM-41 increased with Al loading. Contrary, the presence of Al in the MCM-41 mesoporous structure resulted in a decrease of the crystallinity and specific surface area possibly due to the presence of Al species in highly distorted tetrahedral structures and Al extra-framework or amorphous alumina occluded in the pores. The MCM-41 type mesoporous materials obtained in this work show similar characteristics of those synthesized by conventional hydrothermal methods. (author)

  13. One-pot fabrication of Co{sub 3}O{sub 4} microspheres via hydrothermal method at low temperature for high capacity supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Chao; Zhang, Jinfeng [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Deng, Yida, E-mail: yida.deng@tju.edu.cn [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Zhong, Cheng [School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China); Liu, Lei [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); Hu, Wenbin [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240 (China); School of Material Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2015-09-15

    Highlights: • Take full advantage of the easily oxidized feature of cobalt (II) complexes ammonia. • Low temperature method was applied with absence of subsequent calcination process. • The Co{sub 3}O{sub 4} microspheres possess extraordinary electrochemical properties. - Abstract: Co{sub 3}O{sub 4} microspheres were successfully produced with one-step low temperature hydrothermal method and their electrochemical properties have been investigated. By means of utilizing easily oxidized characteristic of cobalt complexes ammonia, the Co{sub 3}O{sub 4} microspheres were synthesized for the first time with an extremely low hydrothermal temperature (100 °C). In the absent case of surfactant, these Co{sub 3}O{sub 4} microspheres with a diameter of ca. 500 nm and smooth surface were prepared with the assistance of nitrate. Influences concerning about temperature and concentration of nitrate on morphology and size distribution were thoroughly discussed. Electrochemical characterization indicated that the Co{sub 3}O{sub 4} microspheres exhibited high specific capacitance of 850, 780, 700, 630 F/g at current densities of 1, 2, 4, 8 A/g, respectively. And after 1000 cycles, the devices with Co{sub 3}O{sub 4} microspheres showed high charge/discharge reversibility with an efficiency of 90.8% at a current density of 2 A/g.

  14. Synthesis and oxygen vacancy related NO{sub 2} gas sensing properties of ZnO:Co nanorods arrays gown by a hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Changwei, E-mail: qingyihaiyanas@163.com; Liang, Feng; Xue, Shuwen

    2015-10-30

    Highlights: • Co doped ZnO:Co nanorods were grown by hydrothermal method. • The NO{sub 2} response reaches a maximum value of 88 at 210 °C. • The stability of NO{sub 2} on ZnO is enhanced with the presence of V{sub O}. - Abstract: Highly ordered Co doped ZnO:Co nanorods arrays with Co concentrations of 1.6, 1.9 and 3.1 at% were uniformly grown on FTO glass substrate by hydrothermal method. The X-ray diffraction patterns of the undoped and Co doped ZnO nanorods revealed characteristic peaks of (1 0 0), (0 0 2), (1 0 1), (1 0 3) and (1 1 2), corresponding to the hexagonal wurtzite phase of ZnO. For ZnO:Co nanorods with Co concentrations of 3.1 at%, the NO{sub 2} response reached a maximum value of 88 at temperature of 210 °C. However, the response of ZnO:Co nanorods with Co concentrations of 3.1 at% decreased from 82 to 29 with the increasing of O{sub 2} annealing temperature from 0 to 700 °C. As confirmed by the XPS, PL, Raman and I–V results, the oxygen vacancies and electron concentrations were the dominating effects and an oxygen vacancy mediated NO{sub 2} sensing mechanism was presented and discussed.

  15. Photocatalytic properties of h-WO{sub 3} nanoparticles obtained by annealing and h-WO{sub 3} nanorods prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Boyadjiev, Stefan I., E-mail: boiajiev@gmail.com [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Nagy-Kovács, Teodóra [Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Lukács, István [Hungarian Academy of Sciences, Research Centre for Energy, Institute of Technical Physics and Materials Science, H-1121 Budapest, Konkoly Thege M. út 29-33 (Hungary); Szilágyi, Imre M., E-mail: imre.szilagyi@mail.bme.hu [MTA-BME Technical Analytical Chemistry Research Group, Szent Gellért tér 4, Budapest, H-1111 (Hungary); Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, Szent Gellért tér 4, Budapest, H-1111 (Hungary)

    2016-03-25

    In the present study, two different methods for preparing hexagonal WO{sub 3} (h-WO{sub 3}) photocatalysts were used - controlled thermal decomposition and hydrothermal synthesis. WO{sub 3} nanoparticles with hexagonal structure were obtained by annealing (NH{sub 4}){sub x}WO{sub 3-y} at 500 °C in air. WO{sub 3} nanorods were prepared by a hydrothermal method using sodium tungstate Na{sub 2}WO{sub 4}, HCl, (COOH){sub 2} and NaSO{sub 4} precursors at 200 °C. The formation, morphology, structure and composition of the as-prepared nanoparticles and nanorods were studied by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM-EDX). The photocatalytic activity of the h-WO{sub 3} nanoparticles and nanorods was studied by decomposing methyl orange in aqueous solution under UV light irradiation.

  16. Zn(II)-PEG 300 globules as soft template for the synthesis of hexagonal ZnO micronuts by the hydrothermal reaction method.

    Science.gov (United States)

    Shi, Xixi; Pan, Lingling; Chen, Shuoping; Xiao, Yong; Liu, Qiaoyun; Yuan, Liangjie; Sun, Jutang; Cai, Lintao

    2009-05-19

    Hexagonal ZnO micronuts (HZMNs) have been successfully synthesized with the assistance of poly(ethylene glycol) (PEG) 300 via a hydrothermal method. The structure and morphology of the HZMNs were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). An individual ZnO micronut is revealed as twinned crystals. Time-dependent investigation shows that the growth of HZMNs involves a dissolution-recrystallization process followed by Ostwald ripening, in which is the first formed solid ZnO particles dissolve and transform to HZMNs with hollow structure. PEG 300 has been found to play a crucial role in the growth of this unique hollow structure. TEM observations show that the PEG chains aggregate to globules in water, which then have interaction with the dissolved zinc species to form the globules in a coiled state under hydrothermal conditions. These Zn(II)-PEG 300 globules act as soft template for the growth of HZMNs, and the possible growth mechanism is proposed. The room-temperature photoluminescence (PL) spectrum shows red emission around 612 nm with a full width at half-maximum (fwhm) only about 13 nm.

  17. Synthesis of BiFeO3 thin films on single-terminated Nb : SrTiO3 (111 substrates by intermittent microwave assisted hydrothermal method

    Directory of Open Access Journals (Sweden)

    Ivan Velasco-Davalos

    2016-06-01

    Full Text Available We report on a simple and fast procedure to create arrays of atomically flat terraces on single crystal SrTiO3 (111 substrates and the deposition of ferroelectric BiFeO3 thin films on such single-terminated surfaces. A microwave-assisted hydrothermal method in deionized water and ammonia solution selectively removes either (SrO34− or Ti4+ layers to ensure the same chemical termination on all terraces. Measured step heights of 0.225 nm (d111 and uniform contrast in the phase image of the terraces confirm the single termination in pure and Nb doped SrTiO3 single crystal substrates. Multiferroic BiFeO3 thin films were then deposited by the same microwave assisted hydrothermal process on Nb : SrTiO3 (111 substrates. Bi(NO33 and Fe(NO33 along with KOH served as the precursors solution. Ferroelectric behavior of the BiFeO3 films on Nb : SrTiO3 (100 substrates was verified by piezoresponse force microscopy.

  18. Pt. 1: Decommissioning of nuclear facilities. Pt. 2: Methods of decommissioning of nuclear facilities

    International Nuclear Information System (INIS)

    Steinkilberg, W.

    1982-01-01

    In the present paper the different steps of dismantlement of nuclear facilities are dealt with. First the planning principles for decomminconing are discussed and then the planning of the reactorblock dismantlement in the FR2 research reactor is described. (RW)

  19. In-situ deposition of hematite (α-Fe2O3) microcubes on cotton cellulose via hydrothermal method

    Science.gov (United States)

    Gili, M.; Latag, G.; Balela, M.

    2018-03-01

    Hematite microcubes with truncated edges have been successfully deposited on cotton cellulose via one-step hydrothermal process using anhydrous FeCl3 and glycine as Fe(III) precursor and chelating agent, respectively. The amount of glycine significantly affects the morphology and yield of hematite. The addition of 0.495 g of glycine to 50 ml of 0.1 M FeCl3 solution with 0.400 g of cotton resulted to hematite-deposited cellulose having ∼15% hematite content. The reduction of glycine to 0.247 g increased the amount of hematite on the surface of the cotton cellulose to ∼20% by weight. However, the hematite microcubes have a wide size distribution, with particle size in the range of 0.684 μm to 1.520 μm. Without glycine, hematite cannot be formed in the solution.

  20. Hydrothermal synthetic strategies of inorganic semiconducting nanostructures.

    Science.gov (United States)

    Shi, Weidong; Song, Shuyan; Zhang, Hongjie

    2013-07-07

    Because of their unique chemical and physical properties, inorganic semiconducting nanostructures have gradually played a pivotal role in a variety of research fields, including electronics, chemical reactivity, energy conversion, and optics. A major feature of these nanostructures is the quantum confinement effect, which strongly depends on their size, shape, crystal structure and polydispersity. Among all developed synthetic methods, the hydrothermal method based on a water system has attracted more and more attention because of its outstanding advantages, such as high yield, simple manipulation, easy control, uniform products, lower air pollution, low energy consumption and so on. Precise control over the hydrothermal synthetic conditions is a key to the success of the preparation of high-quality inorganic semiconducting nanostructures. In this review, only the representative hydrothermal synthetic strategies of inorganic semiconducting nanostructures are selected and discussed. We will introduce the four types of strategies based on exterior reaction system adjustment, namely organic additive- and template-free hydrothermal synthesis, organic additive-assisted hydrothermal synthesis, template-assisted hydrothermal synthesis and substrate-assisted hydrothermal synthesis. In addition, the two strategies based on exterior reaction environment adjustment, including microwave-assisted and magnetic field-assisted hydrothermal synthesis, will be also described. Finally, we conclude and give the future prospects of this research area.

  1. Structure, chemical bonding states, and optical properties of the hetero-structured ZnO/CuO prepared by using the hydrothermal and the electrospinning methods

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Kyong-Soo; Kim, Jong Wook; Bae, Jong-Seong; Hong, Tae Eun; Jeong, Euh Duck; Jin, Jong Sung; Ha, Myoung Gyu; Kim, Jong-Pil, E-mail: jpkim@kbsi.re.kr

    2017-01-01

    ZnO-branched nanostructures have recently attracted considerable attention due to their rich architectures and promising applications in the field of optoelectronics. Contrary to n-type semiconducting metal oxides, cupric oxide is a p-type semiconductor which can be applied to high-critical-temperature superconductors, photovoltaic materials, field emission, and catalysis. We report the synthesis of the ZnO nanorods on the CuO nanofibers prepared by using the electrospinning method along with the hydrothermal method. As the growing time increases, emission spectra of the hetero-structured ZnO/CuO show that the observed band in the UV region is slightly increased, while the intensity of the green emission is highly enhanced. The hetero-structured ZnO/CuO is found to be a promising candidate for developing renewable devices with photoluminescent behavior and the increased surface to volume ratio.

  2. Hydrothermal precipitation of artificial violarite

    DEFF Research Database (Denmark)

    Jørgensen, W. H.; Toftlund, H.; Warner, T. E.

    2012-01-01

    The nonstoichiometric nickel-ore mineral, violarite, (Ni,Fe)3S4 was prepared as a phase-pure fine powder by a comparatively quick hydrothermal method from an aqueous solution of iron(II) acetate, nickel(II) acetate and DL-penicillamine in an autoclave at 130 °C for 45 h. Powder-XRD showed that th...

  3. Effect of oxygen vacancy induced by pulsed magnetic field on the room-temperature ferromagnetic Ni-doped ZnO synthesized by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Min [Shanghai University, Laboratory for Microstructures, School of Materials Science and Engineering, 149 Yanchang Road, 200072 Shanghai (China); Li, Ying, E-mail: liying62@shu.edu.cn [Shanghai University, Laboratory for Microstructures, School of Materials Science and Engineering, 149 Yanchang Road, 200072 Shanghai (China); Tariq, Muhammad; Hu, Yemin; Li, Wenxian; Zhu, Mingyuan; Jin, Hongmin [Shanghai University, Laboratory for Microstructures, School of Materials Science and Engineering, 149 Yanchang Road, 200072 Shanghai (China); Li, Yibing [School of Chemistry, The University of New South Wales, Sydney, NSW, 2052 (Australia)

    2016-08-05

    Room temperature ferromagnetic 2% Ni doped ZnO rods were synthesized by high pulsed magnetic field-assisted hydrothermal method. A detailed study on the effect of high pulsed magnetic field on morphology, structural and magnetic properties of the ZnO rods has been carried out systematically by varying the intensity of field from 0 to 4 T. X-ray diffraction, Energy-dispersive spectroscopy measurements, and Raman spectra analysis suggest that all the samples have hexagonal wurtzite structure without detectable impurity. Field emission scanning electron microscopy images indicate that the particle size of samples decrease with increasing intensity of field. High resolution transmission electron microscopy observation ensures that the Ni ions addition do not change the wurtzite host matrix. X-ray photoelectron spectroscopy confirms the incorporation of Ni elements as divalent state and the dominant presence of oxygen vacancies in samples fabricated under 4 T pulsed magnetic field. Hysteresis loops demonstrate that the saturation magnetization increased regularly with the mounting magnetic field. On the framework of bound magnetic polaron model, the rising content of oxygen vacancies, as donor defect, lead to the stronger ferromagnetism in samples with pulsed magnetic field. Our findings provide a new insight for tuning the defect density by precisely controlling the intensity of field in order to get the desired magnetic behavior at room temperature. - Graphical abstract: This figure shows the magnetization versus magnetic field curves for 2%Ni doped ZnO as prepared with 0, 1, 2, 3 and 4 T pulsed magnetic field at 290 K. For 0 T sample, no ferromagnetic response is observed. But all the samples synthesized with field were well-defined hysteresis loops. The saturation magnetization estimated from the hysteresis loop come out to be ∼0.0024, 0.0023, 0.0036 and 0.0061 emu/g for 1 T, 2 T, 3 T and 4 T samples, respectively. As shown in the curves, the room

  4. Enhanced visible-light-responsive photodegradation of bisphenol A by Cu, N-codoped titanate nanotubes prepared by microwave-assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Doong, Ruey-an, E-mail: radoong@nctu.edu.tw [Institute of Environmental Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan (China); Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Liao, Chun-Yi [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2017-01-15

    Highlights: • The Cu, N-codoped TNTs were prepared by microwave assisted hydrothermal method. • The Cu(0) in codoped TNTs can serve as electron donors as well as electron meditors. • The surface normalized rate constants for BPA removal by Cu, N-TNT were 1.5–4.3 times higher than that of P25 TiO{sub 2}. • The Cu, N-codoped TNTs prolonged the generation of radicals for at least 5 min. - Abstract: In this study, a rapid and effective microwave-assisted hydrothermal method was developed for the synthesis of Cu, N-codoped titanate nanotubes (Cu, N-TNTs) to enhance the photocatalytic degradation efficiency and rate of bisphenol A (BPA) under UV and visible light irradiations. The TNTs were first synthesized at 150 °C for 3 h under microwave heating conditions followed by the calcination at 450 °C in the presence of 6 wt% Cu ions and N{sub 2}/NH{sub 3} to fabricate Cu, N-TNTs composites. The Cu, N-TNTs exhibited excellent photocatalytic activity toward BPA degradation under UV and visible light irradiations. The X-ray photoelectron spectra indicated that Cu species in Cu, N-TNTs were mainly in zerovalent form and could serve as the electron donors as well as shuttling species to accelerate the photodegradation of BPA. In addition, the nitrogen atoms were incorporated into the anatase lattices to increase the visible-light-responsive capability. The surface normalized reaction rate constants for BPA degradation were 4.3 and 1.5 times higher than those of Degussa P25 TiO{sub 2} under UV and visible light irradiations, respectively. The electron spin resonance spectra showed that Cu, N-codoped TNTs prolonged the generation of oxygen-containing radicals for at least 5 min, resulting in the significant enhancement of photodegradation efficiency and rate of BPA. Results obtained in this study open a new avenue by using simple and effective microwave-assisted hydrothermal method to fabricate low dimensional codoped TNTs which can be potentially applied in a wide

  5. Enhanced visible-light-responsive photodegradation of bisphenol A by Cu, N-codoped titanate nanotubes prepared by microwave-assisted hydrothermal method

    International Nuclear Information System (INIS)

    Doong, Ruey-an; Liao, Chun-Yi

    2017-01-01

    Highlights: • The Cu, N-codoped TNTs were prepared by microwave assisted hydrothermal method. • The Cu(0) in codoped TNTs can serve as electron donors as well as electron meditors. • The surface normalized rate constants for BPA removal by Cu, N-TNT were 1.5–4.3 times higher than that of P25 TiO_2. • The Cu, N-codoped TNTs prolonged the generation of radicals for at least 5 min. - Abstract: In this study, a rapid and effective microwave-assisted hydrothermal method was developed for the synthesis of Cu, N-codoped titanate nanotubes (Cu, N-TNTs) to enhance the photocatalytic degradation efficiency and rate of bisphenol A (BPA) under UV and visible light irradiations. The TNTs were first synthesized at 150 °C for 3 h under microwave heating conditions followed by the calcination at 450 °C in the presence of 6 wt% Cu ions and N_2/NH_3 to fabricate Cu, N-TNTs composites. The Cu, N-TNTs exhibited excellent photocatalytic activity toward BPA degradation under UV and visible light irradiations. The X-ray photoelectron spectra indicated that Cu species in Cu, N-TNTs were mainly in zerovalent form and could serve as the electron donors as well as shuttling species to accelerate the photodegradation of BPA. In addition, the nitrogen atoms were incorporated into the anatase lattices to increase the visible-light-responsive capability. The surface normalized reaction rate constants for BPA degradation were 4.3 and 1.5 times higher than those of Degussa P25 TiO_2 under UV and visible light irradiations, respectively. The electron spin resonance spectra showed that Cu, N-codoped TNTs prolonged the generation of oxygen-containing radicals for at least 5 min, resulting in the significant enhancement of photodegradation efficiency and rate of BPA. Results obtained in this study open a new avenue by using simple and effective microwave-assisted hydrothermal method to fabricate low dimensional codoped TNTs which can be potentially applied in a wide variety of fields of

  6. User's guide for evaluating physical security capabilities of nuclear facilities by the EASI method

    International Nuclear Information System (INIS)

    Bennett, H.A.

    1977-06-01

    This handbook is a guide for evaluating physical security of nuclear facilities using the ''Estimate of Adversary Sequence Interruption (EASI)'' method and a hand-held programmable calculator. The handbook is intended for use by personnel at facilities where special nuclear materials are used, processed, or stored. It may also be used as a design aid for such facilities by potential licensees

  7. Reactor auxiliary cooling facility and coolant supplying method therefor

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Koji; Kinoshita, Shoichiro

    1996-06-07

    A reactor auxiliary cooling facility of the present invention comprises a coolant recycling line for recycling coolants by way of a reactor auxiliary coolant pump and a cooling load, a gravitational surge tank for supplying coolants to the coolant recycling line and a supplemental water supplying line for supplying a supply the supplemental water to the tank. Then, a pressurization-type supply water surge tank is disposed for operating the coolant recycling line upon performing an initial system performance test in parallel with the gravitational surge tank. With such a constitution, the period of time required from the start of the installation of reactor auxiliary cooling facilities to the completion of the system performance test can be shortened at a reduced cost without enlarging the scale of the facility. (T.M.)

  8. Reactor auxiliary cooling facility and coolant supplying method therefor

    International Nuclear Information System (INIS)

    Ando, Koji; Kinoshita, Shoichiro.

    1996-01-01

    A reactor auxiliary cooling facility of the present invention comprises a coolant recycling line for recycling coolants by way of a reactor auxiliary coolant pump and a cooling load, a gravitational surge tank for supplying coolants to the coolant recycling line and a supplemental water supplying line for supplying a supply the supplemental water to the tank. Then, a pressurization-type supply water surge tank is disposed for operating the coolant recycling line upon performing an initial system performance test in parallel with the gravitational surge tank. With such a constitution, the period of time required from the start of the installation of reactor auxiliary cooling facilities to the completion of the system performance test can be shortened at a reduced cost without enlarging the scale of the facility. (T.M.)

  9. Optical and structural properties of ZnO nanorods grown on graphene oxide and reduced graphene oxide film by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Alver, U., E-mail: alver@ksu.edu.tr [Department of Physics, Kahramanmaras Sutcu Imam University, K. Maras 46100 (Turkey); Zhou, W.; Belay, A.B. [Nanoscience and Technology Center, University of Central Florida, Orlando, FL 32816 (United States); Florida Solar Energy Center, Cocoa, FL 32922 (United States); Krueger, R. [Nanoscience and Technology Center, University of Central Florida, Orlando, FL 32816 (United States); Davis, K.O.; Hickman, N.S. [Nanoscience and Technology Center, University of Central Florida, Orlando, FL 32816 (United States); Florida Solar Energy Center, Cocoa, FL 32922 (United States)

    2012-01-15

    ZnO nanorods were grown on graphene oxide (GO) and reduced graphene oxide (RGO) films with seed layers by using simple hydrothermal method. The GO films were deposited by spray coating and then annealed at 400 Degree-Sign C in argon atmosphere to obtain RGO films. The optical and structural properties of the ZnO nanorods were systematically studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and ultraviolet-visible spectroscopy. The XRD patterns and SEM images show that without a seed layer, no ZnO nanorod deposition occurs on GO or RGO films. Transmittance of ZnO nanorods grown on RGO films was measured to be approximately 83% at 550 nm. Furthermore, while transmittance of RGO films increases with ZnO nanorod deposition, transmittance of GO decreases.

  10. The gas-sensing properties of thick film sensors based on nano-ZnFe2O4 prepared by hydrothermal method

    International Nuclear Information System (INIS)

    Chu Xiangfeng; Jiang Dongli; Zheng Chenmou

    2006-01-01

    ZnFe 2 O 4 sensors were fabricated from nano-ZnFe 2 O 4 powders prepared by hydrothermal method and their gas-sensing properties were investigated. It was found that the phase composition of the product and the gas-sensing properties greatly depend on the reaction pH value and the reaction temperature. Nano-ZnFe 2 O 4 powders could be obtained at a pH of 8-10 and the sensor based on the nano-ZnFe 2 O 4 powder prepared at 220 deg. C exhibited the best performance, characterized by high sensitivity to low concentrations of C 2 H 5 OH at 180 deg. C, especially, the sensitivity to 100 ppm C 2 H 5 OH was as high as 76

  11. The Effect of Sodium Dodecyl Sulfate (SDS and Cetyltrimethylammonium Bromide (CTAB on the Properties of ZnO Synthesized by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Yun Hin Taufiq-Yap

    2012-10-01

    Full Text Available ZnO nanostructures were synthesized by hydrothermal method using different molar ratios of cetyltrimethylammonium bromide (CTAB and Sodium dodecyl sulfate (SDS as structure directing agents. The effect of surfactants on the morphology of the ZnO crystals was investigated by field emission scanning electron microscopy (FESEM and transmission electron microscopy (TEM techniques. The results indicate that the mixture of cationic-anionic surfactants can significantly modify the shape and size of ZnO particles. Various structures such as flakes, sheets, rods, spheres, flowers and triangular-like particles sized from micro to nano were obtained. In order to examine the possible changes in other properties of ZnO, characterizations like powder X-ray diffraction (PXRD, thermogravimetric and differential thermogravimetric analysis (TGA-DTG, FTIR, surface area and porosity and UV-visible spectroscopy analysis were also studied and discussed.

  12. A prototype Ultraviolet Light Sensor based on ZnO Nanoparticles/Graphene Oxide Nanocomposite Using Low Temperature Hydrothermal Method

    International Nuclear Information System (INIS)

    Al-Fandi, M; Oweis, R; Khwailah, H; Al-Hattami, S; Al-Shawwa, E; Albiss, B A; Al-Akhras, M-Ali; Qutaish, H; AlZoubi, T

    2015-01-01

    A new prototype UV nanosensor using ZnO nanoparticles (NPs)/graphene oxide (GO) nanocomposite (ZnO-NP/GO) on silicon substrate is reported in this paper. The hybrid nanocomposite structure has been developed by an optimized hydrothermal process at low growth temperature (∼50 °C). In this hybrid nanosensor, the ZnO nanoparticles act as UV- absorbing and charge carrier generating material, while graphene with its superior electrical conductivity has been used as a charge transporting material. Various nanostructure characterization techniques were intensively utilized including SEM, EDX, XRD, FTIR and UV-VIS. Also, the I-V measurement was employed to evaluate the prototype sensor. The morphological SEM analysis showed that the ZnO-NPs (average diameter of 20 nm) were dispersed evenly on the GO sheets. As well, the EDX spectra confirmed the exact chemical composition of the intended structure. The room temperature UV-VIS measurement revealed an enhanced optical absorption of UV-light at an absorption band centered on 375 nm. The improved optical and electrical properties were observed at an optimum relative concentration of 1:10. Under UV light illumination, the measured I-V characteristic of the prototype detector exhibited a considerable photocurrent increase of the ZnO-NP/GO nanocomposite compared to pristine ZnO nanostructure. These results can be promising for future enhanced UV- sensing applications. (paper)

  13. Influence of mineralizer agents on the growth of crystalline CeO2 nanospheres by the microwave-hydrothermal method

    International Nuclear Information System (INIS)

    Deus, R.C.; Cilense, M.; Foschini, C.R.; Ramirez, M.A.; Longo, E.; Simões, A.Z.

    2013-01-01

    Cystalline ceria (CeO 2 ) nanoparticles have been synthesized by a simple and fast microwave-assisted hydrothermal (MAH) under NaOH, KOH, and NH 4 OH mineralizers added to a cerium ammonium nitrate aqueous solution. The products were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transformed-IR and Raman spectroscopies. Rietveld refinement reveals a cubic structure with a space group Fm3m while infrared data showed few traces of nitrates. Field emission scanning microcopy (FEG-SEM) revealed a homogeneous size distribution of nanometric CeO 2 nanoparticles. The MAH process in KOH and NaOH showed most effective to dehydrate the adsorbed water and decrease the hydrogen bonding effect leaving a weakly agglomerated powder of hydrated ceria. TEM micrographs of CeO 2 synthesized under MAH conditions reveal particles well-dispersed and homogeneously distributed. The MAH enabled cerium oxide to be synthesized at 100 °C for 8 min.

  14. A review of the facile (FN) method in particle transport theory

    International Nuclear Information System (INIS)

    Garcia, R.D.M.

    1986-02-01

    The facile F N method for solving particle transport problems is reviewed. The fundamentals of the method are summarized, recent developments are discussed and several applications of the method are described in detail. (author) [pt

  15. ß-Ga2O3 nanorod synthesis with a one-step microwave irradiation hydrothermal method and its efficient photocatalytic degradation for perfluorooctanoic acid.

    Science.gov (United States)

    Zhao, Baoxiu; Li, Xiang; Yang, Long; Wang, Fen; Li, Jincheng; Xia, Wenxiang; Li, Weijiang; Zhou, Li; Zhao, Colin

    2015-01-01

    ß-Ga2O3 nanorod was first directly prepared by the microwave irradiation hydrothermal way without any subsequent heat treatments, and its characterizations were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), UV-Vis diffuse reflection spectroscopy techniques, and also its photocatalytic degradation for perfluorooctanoic acid (PFOA) was investigated. XRD patterns revealed that ß-Ga2O3 crystallization increased with the enhancement of microwave power and the adding of active carbon (AC). PFOA, as an environmental and persistent pollutant, is hard decomposed by hydroxyl radicals (HO·); however, it is facilely destroyed by ß-Ga2O3 photocatalytic reaction in an anaerobic atmosphere. The important factors such as pH, ß-Ga2O3 dosage and bubbling atmosphere were researched, and the degradation and defluorination was 98.8% and 56.2%, respectively. Reductive atmosphere reveals that photoinduced electron may be the major reactant for PFOA. Furthermore, the degradation kinetics for PFOA was simulated and constant and half-life was calculated, respectively. © 2014 The American Society of Photobiology.

  16. Facile hydrothermal synthesis and characterization of cesium-doped PbI2 nanostructures for optoelectronic, radiation detection and photocatalytic applications

    Science.gov (United States)

    Shkir, Mohd; AlFaify, S.; Yahia, I. S.; Hamdy, Mohamed S.; Ganesh, V.; Algarni, H.

    2017-10-01

    Low-temperature hydrothermal-assisted synthesis of pure and cesium (Cs) (1, 3, 5, 7 and 10 wt%) doped lead iodide (PbI2) nanorods and nanosheets have been achieved successfully for the first time. The structural and vibrational studies confirm the formation of a 2H-polytypic PbI2 predominantly. Scanning electron microscope analysis confirms the formation of well-aligned nanorods of average size 100 nm at low concentration and nanosheets of average thicknesses in the range of 20-40 nm at higher concentrations of Cs doping. The presence of Cs doping was confirmed by energy dispersive X-ray study. Ultra-violet-visible absorbance spectra were recorded, and energy gap was calculated in the range of 3.33 to 3.45 eV for pure and Cs-doped PbI2 nanostructures which is higher than the bulk value (i.e., 2.27 eV) due to quantum confinement effect. Dielectric constant, loss, and AC conductivity studies have been done. Enhancement in Gamma linear absorption coefficient due to Cs doping confirms the suitability of prepared nanostructures for radiation detection applications. Furthermore, the photocatalytic performance of the synthesized nanostructures was evaluated in the decolorization of methyl green (MG) and methyl orange (MO) under the illumination of visible light (λ > 420 nm). The observed photocatalytic activity for 5 and 7 wt% Cs-doped PbI2 was observed to be more than pure PbI2 and also > 10 times higher than the commercially available photocatalysts. The results suggest that the prepared nanostructures are highly applicable in optoelectronic, radiation detection and many other applications. [Figure not available: see fulltext.

  17. Morphologically tuned 3D/1D rutile TiO{sub 2} hierarchical hybrid microarchitectures engineered by one-step surfactant free hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Maria John, Maria Angelin Sinthiya [Crystal Growth and Thin Film Laboratory, Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM University, Kattankulathur 603203, Tamil Nadu (India); Ramamurthi, K., E-mail: ramamurthi.k@ktr.srmuniv.ac.in [Crystal Growth and Thin Film Laboratory, Department of Physics and Nanotechnology, Faculty of Engineering and Technology, SRM University, Kattankulathur 603203, Tamil Nadu (India); Sethuraman, K. [School of Physics, Madurai Kamaraj University, Madurai 625021, Tamil Nadu (India); Ramesh Babu, R. [Crystal Growth and Thin Film Laboratory, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India)

    2017-05-31

    Highlights: • TiO{sub 2} 1D-NRs are tuned to 3D/1D-HHMs by increasing growth temperature-first report. • TiO{sub 2} seeded glass substrates are used to reduce the lattice mismatch of TiO{sub 2} HHMs. • Growth temperature influences the structural, morphological and optical properties. • Possible growth mechanism is proposed for morphological changes. - Abstract: Present investigation reports on the surfactant free hydrothermal synthesize of the morphologically tuned hierarchical hybrid rutile titanium oxide (TiO{sub 2}) microarchitectures showing three dimensional microflower structures and cook pine tree like structures on the one dimensional nanorods formed over TiO{sub 2} seed layer coated glass substrates by tuning growth temperature. TiO{sub 2} seed layer of ∼100 nm thick was coated on the glass substrates employing sol–gel spin coating method and then rutile TiO{sub 2} microarchitectures were synthesized on the TiO{sub 2} seed layer by one-step surfactant free hydrothermal method. Deposited samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, UV–vis spectroscopy and photoluminescence spectroscopy techniques. Influence of the growth temperature on the crystallinity, morphology and optical properties along with the growth mechanism to achieve hierarchical microarchitectures was investigated. Present work revealed that the structural, morphological and optical properties of the TiO{sub 2} hierarchical microarchitectures strongly depend on the growth temperature. Further we proposed a model for the cause to effect possible morphological changes of rutile TiO{sub 2} microarchitectures as a function of growth temperatures on the TiO{sub 2} seeded glass substrates.

  18. Preparation and photoluminescence characteristics of In(OH){sub 3}:xTb{sup 3+} obtained by Microwave-Assisted Hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Motta, F.V., E-mail: fabiana@ct.ufrn.br [DEMAT, CT, UFRN, Av. Sen. Salgado Filho 3000, CEP 59072-970 Natal, RN (Brazil); Marques, A.P.A. [UNIFESP, Rua Prof. Artur Riedel 275, CEP 09972-270 Diadema, SP (Brazil); Li, M.S. [IFSC, USP, Av. Trabalhador São Carlense 400, CEP 13566-590 São Carlos, SP (Brazil); Abreu, M.F.C. [LIEC, DQ, UFSCar, Via Washington Luiz, km 235, CEP 13565-905 São Carlos, SP (Brazil); Paskocimas, C.A.; Bomio, M.R.D. [DEMAT, CT, UFRN, Av. Sen. Salgado Filho 3000, CEP 59072-970 Natal, RN (Brazil); Souza, R.P. [DEP, CT, UFRN, Av. Sen. Salgado Filho 3000, CEP 59072-970 Natal, RN (Brazil); Varela, J.A. [LIEC, IQ, UNESP, Rua Francisco Degni s/n, CEP 14801-907 Araraquara, SP (Brazil); Longo, E. [LIEC, DQ, UFSCar, Via Washington Luiz, km 235, CEP 13565-905 São Carlos, SP (Brazil)

    2013-03-15

    Highlights: ► We report the preparation by Microwave-Hydrothermal method of In(OH){sub 3}:xTb{sup 3+}. ► Nanostructures were obtained at a low temperature. ► The crystallite size decreased with terbium doping level. ► The nucleation–dissolution–recrystallization mechanism is promoted by processing. ► This material is a highly promising candidate for photoluminescent applications. -- Abstract: Crystalline terbium-doped indium hydroxide structures were prepared by a rapid and efficient Microwave-Assisted Hydrothermal (MAH) method. Nanostructures were obtained at a low temperature. FE-SEM images confirm that these samples are composed of 3D nanostructures. XRD, optical diffuse reflectance and photoluminescence (PL) measurements were used to characterize the products. Emission spectra of terbium-doped indium hydroxide (In(OH){sub 3}:xTb{sup 3+}) samples under excitation (350.7 nm) presented broad band emission referent to the indium hydroxide matrix and {sup 5}D{sub 4} → {sup 7}F{sub 6}, {sup 5}D{sub 4} → {sup 7}F{sub 5}, {sup 5}D{sub 4} → {sup 7}F{sub 4}, and {sup 5}D{sub 4} → {sup 7}F{sub 3} terbium transitions at 495, 550, 590 and 627 nm, respectively. Relative intensities of the Tb{sup 3+} emissions increased as the concentration of this ion increased from 0, 1, 2, 4 and 8 mol%, of Tb{sup 3+}, but the luminescence is drastically quenched for the In(OH){sub 3} matrix.

  19. In situ deposition of graphene nanosheets on wood surface by one-pot hydrothermal method for enhanced UV-resistant ability

    International Nuclear Information System (INIS)

    Wan, Caichao; Jiao, Yue; Li, Jian

    2015-01-01

    Graphical abstract: - Highlights: • The graphene/wood nanocomposites were fabricated via a mild fast one-pot hydrothermal method. • Graphene nanosheets were in situ deposited on the surface of the wood matrix. • The incorporation of graphene nanosheets results in the improvement in the thermal stability of the graphene/wood. • The graphene/wood exhibits superior UV resistance performance. - Abstract: Graphene nanosheets were successfully in situ deposited on the surface of the wood matrix via a mild fast one-pot hydrothermal method, and the resulting hybrid graphene/wood (GW) were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman spectroscopy, and thermogravimetric analysis (TGA). According to the results, the wood matrix was evenly coated by dense uninterrupted multilayer graphene membrane structure, which was formed by layer-by-layer self-assembly of graphene nanosheets. Meanwhile, the graphene coating also induced significant improvement in the thermal stability of GW in comparison with that of the original wood (OW). Accelerated weathering tests were employed to measure and determine the UV-resistant ability of OW and GW. After about six hundred hours of experiments, the surface color change of GW was much less than that of OW; besides, the Fourier transform infrared spectroscopy (FTIR) analysis also proved the less significant changes in surface chemical compositions of GW. The results both indicated that the graphene coating effectively protected wood surface from UV damage. Therefore, this class of GW composite might be expected to be served as high-performance wooden building material for outdoor or some particular harsh environments like strong UV radiation regions use

  20. LiFePO4 Nanostructures Fabricated from Iron(III) Phosphate (FePO4 x 2H2O) by Hydrothermal Method.

    Science.gov (United States)

    Saji, Viswanathan S; Song, Hyun-Kon

    2015-01-01

    Electrode materials having nanometer scale dimensions are expected to have property enhancements due to enhanced surface area and mass/charge transport kinetics. This is particularly relevant to intrinsically low electronically conductive materials such as lithium iron phosphate (LiFePO4), which is of recent research interest as a high performance intercalation electrode material for Li-ion batteries. Many of the reported works on LiFePO4 synthesis are unattractive either due to the high cost of raw materials or due to the complex synthesis technique. In this direction, synthesis of LiFePO4 directly from inexpensive FePO4 shows promise.The present study reports LiFePO4 nanostructures prepared from iron (III) phosphate (FePO4 x 2H2O) by precipitation-hydrothermal method. The sintered powder was characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Inductive coupled plasma-optical emission spectroscopy (ICP-OES), and Electron microscopy (SEM and TEM). Two synthesis methods, viz. bulk synthesis and anodized aluminum oxide (AAO) template-assisted synthesis are reported. By bulk synthesis, micro-sized particles having peculiar surface nanostructuring were formed at precipitation pH of 6.0 to 7.5 whereas typical nanosized LiFePO4 resulted at pH ≥ 8.0. An in-situ precipitation strategy inside the pores of AAO utilizing the spin coating was utilized for the AAO-template-assisted synthesis. The template with pores filled with the precipitate was subsequently subjected to hydrothermal process and high temperature sintering to fabricate compact rod-like structures.

  1. Control of the microstructure and surface chemistry of graphene aerogels via pH and time manipulation by a hydrothermal method.

    Science.gov (United States)

    García-Bordejé, E; Víctor-Román, S; Sanahuja-Parejo, O; Benito, A M; Maser, W K

    2018-02-15

    Three-dimensional graphene aerogels of controlled pore size have emerged as an important platform for several applications such as energy storage or oil-water separation. The aerogels of reduced graphene oxide are mouldable and light weight, with a porosity up to 99.9%, consisting mainly of macropores. Graphene aerogel preparation by self-assembly in the liquid phase is a promising strategy due to its tunability and sustainability. For graphene aerogels prepared by a hydrothermal method, it is known that the pH value has an impact on their properties but it is unclear how pH affects the auto-assembly process leading to the final properties. We have monitored the time evolution of the chemical and morphological properties of aerogels as a function of the initial pH value. In the hydrothermal treatment process, the hydrogel is precipitated earlier and with lower oxygen content for basic pH values (∼13 wt% O) than for acidic pH values (∼20 wt% O). Moreover, ∼7 wt% of nitrogen is incorporated on the graphene nanosheets at basic pH generated by NH 3 addition. To our knowledge, there is no precedent showing that the pH value affects the microstructure of graphene nanosheets, which become more twisted and bent for the more intensive deoxygenation occurring at basic pH. The bent nanosheets attained at pH = 11 reduce the stacking by the basal planes and they connect via the borders, hence leading eventually to higher pore volumes. In contrast, the flatter graphene nanosheets attained under acidic pH entail more stacking and higher oxygen content after a long hydrothermal treatment. The gravimetric absorption capacity of non-polar solvents scales directly with the pore volume. The aerogels have proved to be highly selective, recyclable and robust for the absorption of nonpolar solvents in water. The control of the porous structure and surface chemistry by manipulation of pH and time will also pave the way for other applications such as supercapacitors or batteries.

  2. Facile hydrothermal synthesis of polyhedral Fe{sub 3}O{sub 4} nanocrystals, influencing factors and application in the electrochemical detection of H{sub 2}O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Kefeng [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China); Ni Yonghong, E-mail: niyh@mail.ahnu.edu.cn [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China); Zhang Li [College of Chemistry and Materials Science, Anhui Key Laboratory of Functional Molecular Solids, Anhui Normal University, Wuhu 241000 (China)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Fe{sub 3}O{sub 4} polyhedra had been successfully synthesized by a facile hydrothermal technology. Black-Right-Pointing-Pointer The as-obtained product exhibited the room-temperature ferrimagnetic property. Black-Right-Pointing-Pointer The final product could be prepared into an electrochemical sensor for the detection of H{sub 2}O{sub 2}. - Abstract: Polyhedral Fe{sub 3}O{sub 4} nanocrystals have been successfully synthesized by a facile hydrothermal technique, employing FeSO{sub 4}{center_dot}7H{sub 2}O, N{sub 2}H{sub 4} and NH{sub 3}{center_dot}H{sub 2}O as the reactants without the assistance of any surfactant. The phase of the as-obtained Fe{sub 3}O{sub 4} was characterized by X-ray powder diffraction (XRD) and further proved by Rietveld refinement of XRD data. Energy dispersive spectrometry (EDS) and scanning electron microscopy (SEM) were used for the composition and morphology analyses of the final product. Some factors influencing the formation of polyhedral Fe{sub 3}O{sub 4} nanocrystals were systematically investigated, including the reaction temperature and time, and the original volume ratio of NH{sub 3}{center_dot}H{sub 2}O/N{sub 2}H{sub 4}{center_dot}H{sub 2}O. It was found that the as-prepared Fe{sub 3}O{sub 4} polyhedra exhibited a good electrochemical property in 0.1 M phosphate buffer solution (PBS) with pH 7.0 and could be prepared into an electrochemical sensor for the detection of H{sub 2}O{sub 2}. The linear response range of the sensor was 10.0 Multiplication-Sign 10{sup -6} to 140.0 Multiplication-Sign 10{sup -6} M and a sensitivity was 11.05 {mu}A/mM. Furthermore, the room-temperature magnetic property of the product was also investigated.

  3. Inspection methods for safeguards systems at nuclear facilities

    International Nuclear Information System (INIS)

    Minichino, C.; Richard, E.W.

    1981-01-01

    A project team at Lawrence Livermore National Laboratory has been developing inspection procedures and training materials for the NRC inspectors of safeguards systems at licensed nuclear facilities. This paper describes (1) procedures developed for inspecting for compliance with the Code of Federal Regulations, (2) training materials for safeguards inspectors on technical topics related to safeguards systems, such as computer surety, alarm systems, sampling techniques, and power supplies, and (3) an inspector-oriented methodology for evaluating the overall effectiveness of safeguards systems

  4. Thermochemical parameters of minerals from oxygen-buffered hydrothermal equilibrium data: Method, application to annite and almandine

    Science.gov (United States)

    Zen, E.-A.

    1973-01-01

    Reversed univariant hydrothermal phase-equilibrium reactions, in which a redox reaction occurs and is controlled by oxygen buffers, can be used to extract thermochemical data on minerals. The dominant gaseous species present, even for relatively oxidizing buffers such as the QFM buffer, are H2O and H2; the main problem is to calculate the chemical potentials of these components in a binary mixture. The mixing of these two species in the gas phase was assumed by Eugster and Wones (1962) to be ideal; this assumption allows calculation of the chemical potentials of the two components in a binary gas mixture, using data in the literature. A simple-mixture model of nonideal mixing, such as that proposed by Shaw (1967), can also be combined with the equations of state for oxygen buffers to permit derivation of the chemical potentials of the two components. The two mixing models yield closely comparable results for the more oxidizing buffers such as the QFM buffer. For reducing buffers such as IQF, the nonideal-mixing correction can be significant and the Shaw model is better. The procedure of calculation of mineralogical thermochemical data, in reactions where hydrogen and H2O simultaneously appear, is applied to the experimental data on annite, given by Wones et al. (1971), and on almandine, given by Hsu (1968). For annite the results are: Standard entropy of formation from the elements, Sf0 (298, 1)=-283.35??2.2 gb/gf, S0 (298, 1) =+92.5 gb/gf. Gf0 (298, 1)=-1148.2??6 kcal, and Hf0 (298, 1)=-1232.7??7 kcal. For almandine, the calculation takes into account the mutual solution of FeAl2O4 (Hc) in magnetite and of Fe3O4 (Mt) in hercynite and the temperature dependence of this solid solution, as given by Turnock and Eugster (1962); the calculations assume a regular-solution model for this binary spinel system. The standard entropy of formation of almandine, Sf,A0 (298, 1) is -272.33??3 gb/gf. The third law entropy, S0 (298, 1) is +68.3??3 gb/gf, a value much less than the

  5. Zinc stannate nanostructures: hydrothermal synthesis

    International Nuclear Information System (INIS)

    Baruah, Sunandan; Dutta, Joydeep

    2011-01-01

    Nanostructured binary semiconducting metal oxides have received much attention in the last decade owing to their unique properties rendering them suitable for a wide range of applications. In the quest to further improve the physical and chemical properties, an interest in ternary complex oxides has become noticeable in recent times. Zinc stannate or zinc tin oxide (ZTO) is a class of ternary oxides that are known for their stable properties under extreme conditions, higher electron mobility compared to its binary counterparts and other interesting optical properties. The material is thus ideal for applications from solar cells and sensors to photocatalysts. Among the different methods of synthesizing ZTO nanostructures, the hydrothermal method is an attractive green process that is carried out at low temperatures. In this review, we summarize the conditions leading to the growth of different ZTO nanostructures using the hydrothermal method and delve into a few of its applications reported in the literature. (topical review)

  6. Methods and techniques for decontamination design and construction of facilities

    International Nuclear Information System (INIS)

    Augustin, X.; Cohen, S.

    1986-01-01

    TECHNICATOME and STMI have jointly solved a wide range of problems specific to decontamination from the very design studies up to operation. TECHNICATOME has brought its expertise in the design and construction of nuclear facilities concerned in particular with decontamination and radwaste management. STMI is an experienced operator with expertise in designing tools and developing advanced techniques in the same fields. The expertise of both companies in this field cumulated for many years has resulted in developing techniques and tools adapted to most of the decontamination problems including specific cases [fr

  7. Early test facilities and analytic methods for radiation shielding: Proceedings

    International Nuclear Information System (INIS)

    Ingersoll, D.T.; Ingersoll, J.K.

    1992-11-01

    This report represents a compilation of eight papers presented at the 1992 American Nuclear Society/European Nuclear Society International Meeting. The meeting is of special significance since it commemorates the fiftieth anniversary of the first controlled nuclear chain reaction. The papers contained in this report were presented in a special session organized by the Radiation Protection and Shielding Division in keeping with the historical theme of the meeting. The paper titles are good indicators of their content and are: (1) The origin of radiation shielding research: The Oak Ridge experience, (2) Shielding research at the hanford site, (3) Aircraft shielding experiments at General Dynamics Fort Worth, 1950-1962, (4) Where have the neutrons gone?, a history of the tower shielding facility, (5) History and evolution of buildup factors, (6) Early shielding research at Bettis atomic power laboratory, (7) UK reactor shielding: then and now, (8) A very personal view of the development of radiation shielding theory

  8. Classification and methodical features of fitness and wellness facilities

    Directory of Open Access Journals (Sweden)

    Yu. I. Beliak

    2014-11-01

    Full Text Available Purpose : health and fitness use a large arsenal of different sports and physical activity. Development of fitness industry promotes its expansion and requires classification and methodological features that lead to the use of appropriate fitness programs. Material : more than 60 literature and video of 42 prestigious international fitness - conventions lessons were analyzed. Results : the evolution of species fitness and wellness, as well as the character used in those funds. Conclusions : as a means of improving classification attribute fitness appropriate to use their orientation, according to which they are divided into aerobic, strength exercises that promote flexibility and psychomotor coordination. The main methodological features fitness facilities are highlighted: the variety and interchangeability, clear regulation, the ability to transform, to exercise a selective effect on the body, the ability to solve a wide range of tasks, innovation.

  9. Fault diagnosis method for area gamma monitors in Nuclear Facilities

    International Nuclear Information System (INIS)

    Srinivas Reddy, P.; Amudhu Ramesh Kumar, R.; Geo Mathews, M.; Amarendra, G.

    2016-01-01

    Area Gamma Monitors (AGM) using Geiger-Muller (GM) counter are deployed in nuclear facilities for detection of gamma radiation. The AGMs display the dose rate locally and in Data Acquisition System (DAS) at central monitoring station. It also provides local visual and audio alarms in case of dose rate exceeding alarm set point. Regular surveillance checking, testing and calibration of AGMs are mandatory as per safety guidelines. This paper describes quick testing the AGMs without using radioactive source. The four point High Voltages (HV) and Discriminator Bias (DB) voltage characteristics are used to diagnose the state of health of GM counter. The profiles of HV and DB voltage are applied during testing of the AGMs

  10. Synthesis of BaTiO{sub 3} and SrTiO{sub 3} by microwave assisted hydrothermal method (MAH) using anatase as titanium precursor

    Energy Technology Data Exchange (ETDEWEB)

    Magalhães, Renata da Silva; Macedo Junior, Wagner Dias; Souza, Agda Eunice de; Teixeira, Silvio Rainho, E-mail: R.S.Magalhaes@hotmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (FCT/UNESP), Presidente Prudente, SP (Brazil); Li, Maximo Siu [Universidade de Sao Paulo (USP), São Carlos, SP (Brazil). Instituto de Física; Longo, Elson [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Instituto de Química

    2016-07-01

    Full text: Strontium and barium titanates (SrTiO{sub 3} (ST) and BaTiO{sub 3} (BT)) in their crystalline form belong to the perovskite (ABO{sub 3}) class. Both display a semiconductor behavior with many interesting properties. The method of synthesis employed and different precursors may influence the morphology and properties of ceramic materials [1,2]. Barium (BT) and strontium (St) titanates were produced using the Microwave Assisted Hydrothermal Method (MAH), different concentrations (1,3 and 6 molL{sup -1}) of mineralizer (KOH) and a different titanium precursor: a complex anatase-hydrogen peroxide. Barium and strontium chloride were used as the other metal precursors. The resulting material were characterized by different techniques such as: X-ray diffraction (XRD), Micro-Raman Spectroscopy (MR), UV-Vis, Scanning Electron microscopy (SEM) and finally their photoluminescent emissions (FL) were recorded at room temperature. The results show that there were differences in crystallinity, morphology, number of formed phases and photoluminescent emission, among the titanate produced with different concentrations of mineralizer. References: [1] A.E. Souza et al., Order–disorder degree of self-assembled clusters: Influence on photoluminescence emission and morphology of Ba{sub x}Sr{sub 1-x}TiO{sub 3} nanocrystals, Chemical Physics Letters 514 (2011) 301–306. [2] T. M. Mazzo et al., Influence of titanium precursor on photoluminescent emission of micro-cube-shaped CaTiO{sub 3}, Journal of Luminescence 165 (2015). (author)

  11. Synthesis of BaTiO3 and SrTiO3 by microwave assisted hydrothermal method (MAH) using anatase as titanium precursor

    International Nuclear Information System (INIS)

    Magalhães, Renata da Silva; Macedo Junior, Wagner Dias; Souza, Agda Eunice de; Teixeira, Silvio Rainho; Li, Maximo Siu; Longo, Elson

    2016-01-01

    Full text: Strontium and barium titanates (SrTiO 3 (ST) and BaTiO 3 (BT)) in their crystalline form belong to the perovskite (ABO 3 ) class. Both display a semiconductor behavior with many interesting properties. The method of synthesis employed and different precursors may influence the morphology and properties of ceramic materials [1,2]. Barium (BT) and strontium (St) titanates were produced using the Microwave Assisted Hydrothermal Method (MAH), different concentrations (1,3 and 6 molL -1 ) of mineralizer (KOH) and a different titanium precursor: a complex anatase-hydrogen peroxide. Barium and strontium chloride were used as the other metal precursors. The resulting material were characterized by different techniques such as: X-ray diffraction (XRD), Micro-Raman Spectroscopy (MR), UV-Vis, Scanning Electron microscopy (SEM) and finally their photoluminescent emissions (FL) were recorded at room temperature. The results show that there were differences in crystallinity, morphology, number of formed phases and photoluminescent emission, among the titanate produced with different concentrations of mineralizer. References: [1] A.E. Souza et al., Order–disorder degree of self-assembled clusters: Influence on photoluminescence emission and morphology of Ba x Sr 1-x TiO 3 nanocrystals, Chemical Physics Letters 514 (2011) 301–306. [2] T. M. Mazzo et al., Influence of titanium precursor on photoluminescent emission of micro-cube-shaped CaTiO 3 , Journal of Luminescence 165 (2015). (author)

  12. Enhanced photochemical catalysis of TiO2 inverse opals by modification with ZnO or Fe2O3 using ALD and the hydrothermal method

    Science.gov (United States)

    Liu, Jiatong; Sun, Cuifeng; Fu, Ming; Long, Jie; He, Dawei; Wang, Yongsheng

    2018-02-01

    The development of porous materials exhibiting photon regulation abilities for improved photoelectrochemical catalysis performance is always one of the important goals of solar energy harvesting. In this study, methods to improve the photocatalytic activity of TiO2 inverse opals were discussed. TiO2 inverse opals were prepared by atomic layer deposition (ALD) using colloidal crystal templates. In addition, TiO2 inverse opal heterostructures were fabricated using colloidal heterocrystals by repeated vertical deposition using different colloidal spheres. The hydrothermal method and ALD were used to prepare ZnO- or Fe2O3-modified TiO2 inverse opals on the internal surfaces of the TiO2 porous structures. Although the photonic reflection band was not significantly varied by oxide modification, the presence of Fe2O3 in the TiO2 inverse opals enhanced their visible absorption. The conformally modified oxides on the TiO2 inverse opals could also form energy barriers and avoid the recombination of electrons and holes. The fabrication of the TiO2 photonic crystal heterostructures and modification with ZnO or Fe2O3 can enhance the photocatalytic activity of TiO2 inverse opals.

  13. Production of Ethylene through Ethanol Dehydration on SBA-15 Catalysts Synthesized by Sol-gel and One-step Hydrothermal Methods.

    Science.gov (United States)

    Autthanit, Chaowat; Jongsomjit, Bunjerd

    2018-02-01

    The present work deals with the catalytic performance of SBA-15 supported catalysts in the gas phase catalytic dehydration of ethanol in the temperature range of 200 to 400°C. The SBA-15 support was incorporated on a zirconium (Zr) and bimetal of zirconium and lanthanum (Zr-La) prepared by sol-gel (SG) and hydrothermal (HT) methods. The catalysts were characterized by means of N 2 physisorption, SEM/EDX, and NH 3 -TPD. The experimental results demonstrated that the Zr-La/SBA-15-HT exhibited the highest catalytic activity. Ethanol conversion and ethylene selectivity were found to increase with increased reaction temperature. The best catalytic results were achieved for Zr-La/SBA-15-HT indicating values of ethanol conversion and ethylene yield of ca. 84% and 80%, respectively at 400°C. The most important parameter influencing their catalytic properties appears to be the interaction between metal and support depending on different methods. The metal dispersion inside the siliceous matrix of SBA-15 has a direct influence on their surface acidity. Meanwhile, the performance of these SBA-15 supported catalysts in ethanol dehydration is also related with the alteration of surface acidity caused by the introduction of Zr and Zr-La.

  14. Evaluate of environment quality for γ irradiation facilities using fuzzy comprehensive judgment method

    International Nuclear Information System (INIS)

    Ha Yiming

    2002-01-01

    The environment quality of Jining Irradiation Centre new γ radiation facility was evaluated by fuzzy comprehensive judgment method. The result showed that the place of γ radiation facility was well and the measures of radiate shelter and environment protect were effective. The environment quality of its area was not obvious change and the result of environment evaluation was first-rate

  15. Analytical throughput-estimating methods for the Hot Fuel Examination Facility

    International Nuclear Information System (INIS)

    Keyes, R.W.; Phipps, R.D.

    1983-01-01

    The Hot Fuel Examination Facility (HFEF) supports the operation and experimental programs of the major Liquid Metal Fast Breeder Reactor (LMFBR) test facilities; specifically, the Fast Flux Test Facility (FFTF), the Experimental Breeder Reactor II (EBR-II), and the Transient Reactor Test (TREAT) Facility. Successful management of HFEF and of LMFBR safety and fuels and materials programs, therefore, requires reliable information regarding HFEF's capability to handle expected or proposed program work loads. This paper describes the 10-step method that has been developed to consider all variables which significantly affect the HFEF examination throughput and quickly provide the necessary planning information

  16. Controlled synthesis of La{sub 1−x}Sr{sub x}CrO{sub 3} nanoparticles by hydrothermal method with nonionic surfactant and their ORR activity in alkaline medium

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Bo Hyun; Park, Shin-Ae [Energy System Major, School of Mechanical Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Park, Bong Kyu [GIFT Center, Pusan National University, Busan, 609-735 (Korea, Republic of); Chun, Ho Hwan, E-mail: chunahh@pusan.ac.kr [Global Core Research Center for Ships and Offshore Plants(GCRC-SOP), Pusan National University, Busan, 609-735 (Korea, Republic of); Kim, Yong-Tae, E-mail: yongtae@pusan.ac.kr [Energy System Major, School of Mechanical Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

    2013-10-15

    Graphical abstract: We demonstrate that Sr-doped LaCrO{sub 3} nanoparticles were successfully prepared by the hydrothermal synthesis method using the nonionic surfactant Triton X-100 and the applicability of La{sub 1−x}Sr{sub x}CrO{sub 3} to oxygen reduction reaction (ORR) electrocatalysis in an alkaline medium. Compared with the nanoparticles synthesized by the coprecipitation method, they showed enhanced ORR activity. - Highlights: • Sr-doped LaCrO{sub 3} nanoparticles were successfully prepared by the hydrothermal method using the nonionic surfactant. • Homogeneously shaped and sized Sr-doped LaCrO{sub 3} nanoparticles were readily obtained. • Compared with the nanoparticles synthesized by the coprecipitation method, they showed an enhanced ORR activity. • The main origin was revealed to be the decreased particle size due to the nonionic surfactant. - Abstract: Sr-doped LaCrO{sub 3} nanoparticles were prepared by the hydrothermal method with the nonionic surfactant Triton X-100 followed by heat treatment at 1000 °C for 10 h. The obtained perovskite nanoparticles had smaller particle size (about 100 nm) and more uniform size distribution than those synthesized by the conventional coprecipitation method. On the other hand, it was identified with the material simulation that the electronic structure change by Sr doping was negligible, because the initially unfilled e{sub g}-band was not affected by the p-type doping. Finally, the perovskite nanoparticles synthesized by hydrothermal method showed much higher ORR activity by over 200% at 0.8 V vs. RHE than those by coprecipitation method.

  17. Combustible gas concentration control facility and operation method therefor

    International Nuclear Information System (INIS)

    Yoshikawa, Kazuhiro; Ando, Koji; Kinoshita, Shoichiro; Yamanari, Shozo; Moriya, Kimiaki; Karasawa, Hidetoshi

    1998-01-01

    The present invention provides a hydrogen gas-control facility by using a fuel battery-type combustible gas concentration reducing device as a countermeasure for controlling a hydrogen gas in a reactor container. Namely, a hydrogen electrode adsorb hydrogen by using an ion exchange membrane comprising hydrogen ions as a charge carrier. An air electrode adsorb oxygen in the air. A fuel battery converts recombining energy of hydrogen and oxygen to electric energy. Hydrogen in this case is supplied from an atmosphere in the container. Oxygen in this case is supplied from the air outside of the container. If hydrogen gas should be generated in the reactor, power generation of is performed by the fuel battery by using hydrogen gas, as a fuel, on the side of the hydrogen electrode of the fuel battery and using oxygen, as a fuel, in the air outside of the container on the side of the air electrode. Then, the hydrogen gas is consumed thereby controlling the hydrogen gas concentration in the container. Electric current generated in the fuel battery is used as an emergency power source for the countermeasure for a severe accident. (I.S.)

  18. Combustible gas concentration control facility and operation method therefor

    Energy Technology Data Exchange (ETDEWEB)

    Yoshikawa, Kazuhiro; Ando, Koji; Kinoshita, Shoichiro; Yamanari, Shozo; Moriya, Kimiaki; Karasawa, Hidetoshi

    1998-09-25

    The present invention provides a hydrogen gas-control facility by using a fuel battery-type combustible gas concentration reducing device as a countermeasure for controlling a hydrogen gas in a reactor container. Namely, a hydrogen electrode adsorb hydrogen by using an ion exchange membrane comprising hydrogen ions as a charge carrier. An air electrode adsorb oxygen in the air. A fuel battery converts recombining energy of hydrogen and oxygen to electric energy. Hydrogen in this case is supplied from an atmosphere in the container. Oxygen in this case is supplied from the air outside of the container. If hydrogen gas should be generated in the reactor, power generation of is performed by the fuel battery by using hydrogen gas, as a fuel, on the side of the hydrogen electrode of the fuel battery and using oxygen, as a fuel, in the air outside of the container on the side of the air electrode. Then, the hydrogen gas is consumed thereby controlling the hydrogen gas concentration in the container. Electric current generated in the fuel battery is used as an emergency power source for the countermeasure for a severe accident. (I.S.)

  19. Applications versus properties of Mg–Al layered double hydroxides provided by their syntheses methods: Alkoxide and alkoxide-free sol–gel syntheses and hydrothermal precipitation

    KAUST Repository

    Chubar, Natalia

    2013-12-01

    A tremendous number of studies have examined layered double hydroxides (LDH) for their technological applications in the ion exchange removal of toxic ions, recovery of valuable substances, catalysis, CO2 capture, as a layered host for storage/delivery of biologically active molecules, additives to plastics and building materials, and other functions. Numerous publications always conclude that the materials (prepared, as a rule, using the oldest synthesis method) are very promising for each investigated application; however, the main chemical industries producing these materials advertise them mainly (or only) as plastic additives. The authors performed extensive research using many of the appropriate methods to compare the structure, surface and adsorptive properties of three Mg-Al LHDs produced by advanced synthesis methods. One industrial sample (by Sasol, Germany) prepared by the alkoxide sol-gel method and two novel Mg-Al LDHs synthesised in-house by alkoxide-free sol-gel and hydrothermal precipitation approaches were investigated. Reasons for the very different adsorptive selectivity of the three LDHs towards arsenate, selenate, phosphate, arsenite and selenite have been provided, highlighting the role of speciation of the interlayer carbonate, aluminium, magnesium, interlayer hydration and moisture content in the adsorptive selectivity towards each toxic anion. This work is the first report presenting the regularities of the LDHs structure, surface and anion exchange properties as a function of their syntheses method. It establishes the links to potential technological applications of each investigated LDH and explains the necessary properties required to make the technological application cost-effective and efficient. The paper might accelerate industrial applications of these advanced materials. © 2013 Elsevier B.V.

  20. Evolution of ZnO architecture on a nanoporous TiO{sub 2} film by a hydrothermal method and the photoelectrochemical performance

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Yinhua; Wu Xiaoli; Zhang Wenli; Ni Liang [School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013 (China); Sun Yueming, E-mail: yms418@126.com [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China)

    2011-03-15

    The synthesis of ZnO architecture on a fluorine-doped SnO{sub 2} (FTO) conducting glass pre-coated with nanoporous TiO{sub 2} film has been achieved by a one-step hydrothermal method at a temperature of 70 deg. C. The effect of the reaction time on the morphology of the ZnO architecture has been investigated, and a possible growth mechanism for the formation of the ZnO architecture is discussed in detail. The morphology and phase structures of the as-obtained composite films have been investigated by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The results show that the growth time greatly affects the morphology of the obtained ZnO architecture. The photoelectrochemical performances of as-prepared composite films are measured by assembling them into dye sensitized solar cells (DSSCs). The DSSC based on the as-prepared composite film (2 h) has obtained the best power conversion efficiency of 1.845%. (semiconductor materials)

  1. Synthesis of LaVO4/TiO2 heterojunction nanotubes by sol-gel coupled with hydrothermal method for photocatalytic air purification.

    Science.gov (United States)

    Zou, Xuejun; Li, Xinyong; Zhao, Qidong; Liu, Shaomin

    2012-10-01

    With the aim of improving the effective utilization of visible light, the LaVO(4)/TiO(2) heterojunction nanotubes were fabricated by sol-gel coupled with hydrothermal method. The photocatalytic ability was demonstrated through catalytic removal of gaseous toluene species. The nanotube samples were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), surface photovoltage (SPV), Raman spectra and N(2) adsorption-desorption measurements. The characterization results showed that the samples with high specific surface areas were of typical nanotubular morphology, which would lead to the high separation and transfer efficiency of photo induced electron-hole pairs. The as-prepared nanotubes exhibited high photocatalytic activity in decomposing toluene species under visible light irradiation with fine photochemical stability. The enhanced photocatalytic performance of LaVO(4)/TiO(2) nanotubes might be attributed to the matching band potentials, the interconnected heterojunction of LaVO(4) versus TiO(2), and the large specific surface areas of nanotubes. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Enhanced Water Oxidation Photoactivity of Nano-Architectured α-Fe2O3-WO3 Composite Synthesized by Single-Step Hydrothermal Method

    Science.gov (United States)

    Rahman, Gul; Joo, Oh-Shim; Chae, Sang Youn; Shah, Anwar-ul-Haq Ali; Mian, Shabeer Ahmad

    2018-04-01

    This study reports the one-step in situ synthesis of a hematite-tungsten oxide (α-Fe2O3-WO3) composite on fluorine-doped tin oxide substrate via a simple hydrothermal method. Scanning electron microscopy images indicated that the addition of tungsten (W) precursor into the reaction mixture altered the surface morphology from nanorods to nanospindles. Energy-dispersive x-ray spectroscopy analysis confirmed the presence of W content in the composite. From the ultraviolet-visible spectrum of α-Fe2O3-WO3, it was observed that absorption began at ˜ 600 nm which corresponded to the bandgap energy of ˜ 2.01 eV. The α-Fe2O3-WO3 electrode demonstrated superior performance, with water oxidation photocurrent density of 0.80 mA/cm2 (at 1.6 V vs. reversible hydrogen electrode under standard illumination conditions; AM 1.5G, 100 mW/cm2) which is 2.4 times higher than α-Fe2O3 (0.34 mA/cm2). This enhanced water oxidation performance can be attributed to the better charge separation properties in addition to the large interfacial area of small-sized particles present in the α-Fe2O3-WO3 nanocomposite film.

  3. Synthesis of barium titanate crystalline nanoparticles using hydrothermal microwave method; Obtencao de nanoparticulas cristalinas de titanato de bario usando metodo hidrotermal assistido por microondas

    Energy Technology Data Exchange (ETDEWEB)

    Souza, A.E.; Silva, R.A.; Teixeira, S.R. [Universidade Estadual Paulista (DFQB/FCT/UNESP), Presidente Prudente, SP (Brazil). Dept. de Fisica, Quimica e Biologia. Lab. de Compositos e Ceramicas Funcionais; Moreira, M.L. [Universidade Federal de Sao Carlos (LiEC/UFSCAR), SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica; Volanti, D.P.; Longo, E. [Universidade Estadual Paulista (LiEC/UNESP), Araraquara, SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica

    2009-07-01

    The hydrothermal microwave method (HTMW) was used in the synthesis of barium titanate (BaTiO{sub 3}) nanoparticles. The solution was prepared in deionized water by using titanium (IV) isopropoxide (C{sub 12}H{sub 28}O{sub 4}Ti), barium chloride (BaCl{sub 2}.2H{sub 2}O) and potassium hydroxide (KOH). Afterwards it was heated in an adapted conventional microwave oven. The system is composed of a temperature controller with thermocouple, a hermetic camera of reaction made of teflon, a manometer and a safety valve. The solution was heated to 140 deg C, at a 140 deg C/min heating rate, and maintained at this temperature for 40 minutes. The obtained ceramic powder was characterized by using X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The XRD data confirms the formation of a high crystalline ceramic material with perovskite structure. The FE-SEM images reveal morphologies with dimensions varying from 27 to 54 nm. (author)

  4. Nanowire Na0.35MnO2 from a hydrothermal method as a cathode material for aqueous asymmetric supercapacitors

    Science.gov (United States)

    Zhang, B. H.; Liu, Y.; Chang, Z.; Yang, Y. Q.; Wen, Z. B.; Wu, Y. P.; Holze, R.

    2014-05-01

    Nanowire Na0.35MnO2 was prepared by a simple and low energy consumption hydrothermal method; its electrochemical performance as a cathode material for aqueous asymmetric supercapacitors in Na2SO4 solution was investigated. Due to the nanowire structure its capacitance (157 F g-1) is much higher than that of the rod-like Na0.95MnO2 (92 F g-1) from solid phase reaction although its sodium content is lower. When it is assembled into an asymmetric aqueous supercapacitor using activated carbon as the counter electrode and aqueous 0.5 mol L-1 Na2SO4 electrolyte solution, the nanowire Na0.35MnO2 shows an energy density of 42.6 Wh kg-1 at a power density of 129.8 W kg-1 based on the total weight of the two electrode material, higher than those for the rod-like Na0.95MnO2, with an energy density of 27.3 Wh kg-1 at a power density of 74.8 W kg-1, and that of LiMn2O4. The new material presents excellent cycling behavior even when dissolved oxygen is not removed from the electrolyte solution. The results hold great promise for practical applications of this cathode material since sodium is much cheaper than lithium and its natural resources are rich.

  5. One-pot synthesis and photoluminescence properties of core/porous-shell olive-like BaWO4 microstructure by a template-assisted hydrothermal method

    Science.gov (United States)

    Zhang, Suyue; Wang, Yunlong; Wang, Cuiping; Zhang, Hui; Shen, Yuhua; Xie, Anjian

    2016-02-01

    Core/porous-shell olive-like crystalline BaWO4 is synthesized by a combined simple hydrothermal method and soft template approach. The prepared product shows an olive-like shape with diameter of ˜2 μm, length of ˜4 μm, and the thickness of the shell of about 65 nm, which are orderly assembled by many nanoparticles. A possible formation mechanism of olive-like BaWO4 microstructure involving interfacial recognization of ions, nucleation, aggregation, in situ growth and Ostwald ripening process is proposed. Polyacrylic acid sodium (PAAS) as a template plays an important role in inducing the nucleation and growth of olive-like BaWO4 microcrystalline. Other shapes of BaWO4 microcrystalline are also fabricated by varying the concentration of PAAS and Ba2+. The olive-like product with a core-shell structure which exists a large number of pores on crystal surface shows excellent photoluminescence property, which have potentially applied prospects in fields such as light display systems etc.

  6. Ag doped TiO2 nanoparticles prepared by hydrothermal method and coating of the nanoparticles on the ceramic pellets for photocatalytic study: Surface properties and photoactivity

    Directory of Open Access Journals (Sweden)

    Oguzhan Avciata

    2018-02-01

    Full Text Available In this work, Ag doped nano TiO2 photocatalysts were synthesized in powder form by hydrothermal method at 180 ºC in 120 min using different reduction agents. The synthesized powders were characterized by powder X-ray diffraction (XRD, Energydispersive X-ray spectroscopy (EDS, Surface area measurements (BET, Transmission electron microscopy (TEM and scanning electron microscopy (SEM analyses. The effect of reduction agents on the morphological properties of Ag doped nano TiO2 has been studied. We have been observed that the use of different reduction agents affects the particle size and surface area. Ag doped nano TiO2 photocatalysts were coated to the ceramic pellets by dip coating technique for photocatalytic study. Photocatalytic properties of the synthesized powder were examined in a circulating aquarium filled with indigo blue (IB solution under UV irradiation. Periodical UV spectrophotometric analysis showed that indigo blue (IB has been degraded and its concentration has decreased under UV irradiation by time.

  7. Photoemission properties of Eu-doped Zr1- x Ce x O2 (x = 0-0.2) nanoparticles prepared by hydrothermal method

    Science.gov (United States)

    Ozawa, Masakuni; Matsumoto, Masashi; Hattori, Masatomo

    2018-01-01

    Photoluminescent Eu-doped ZrO2 and Zr1- x Ce x O2 (x = 0-0.2) nanoparticles were prepared by a hydrothermal method. X-ray diffraction and Raman spectra indicated the formation of tetragonal crystals of ZrO2 and its solid solutions with a grain size of less than 10 nm diameter after heat treatment at 400 °C. The photoemission spectra of Zr1- x Ce x O2:Eu3+ nanocrystalline samples showed the typical emission of Eu3+ ions assigned to 5D0 → 7F1 (590 nm) and 5D0 → 7F2 (610 nm) transitions and additional emissions of 5D0 → 7F J with higher J of 3-5. Increasing the CeO2 concentration reduced the emission intensity, and the emission peak shift was affected by a local lattice distortion, i.e., CeO2 concentration. The present study provided fundamental knowledge that is expected to enable the fabrication of ZrO2-based nanocrystal phosphor materials and a measure for controlling the emission peak shift and intensity in oxide fluorite-based phosphor.

  8. Photocatalytic Degradation of Rhodamine B Dye over Novel Porous TiO2-SnO2 Nanocomposites Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2014-01-01

    Full Text Available The photocatalytic degradation of Rhodamine B dye was successfully carried out under UV irradiation over porous TiO2-SnO2 nanocomposites with various molar ratios of Ti/Sn (4–12 synthesized by hydrothermal method using polystyrene microspheres as template. The combination of TiO2 with SnO2 can obtain high quantum yield of TiO2, and then achieve the high photocatalytic activity. And its porous structure can provide large surface area, leading to more adsorption and fast transfer of dye pollutant. Structural and textural features of the samples were investigated by X-ray diffraction (XRD, transmission electron microscopy (TEM, and N2 sorption techniques. Both adsorption and UV irradiation contribute to decolorization of about 100% of Rhodamine B dye over the sample TiSn10 after 30 min of the photocatalytic reaction, while the decomposition of Rhodamine B dye is only 62% over pure titania (Degussa P25.

  9. One-step rapid synthesis of ultrafine γ-Ga2O3 nanocrystals by microwave hydrothermal method in ammonium hydroxide medium

    Science.gov (United States)

    Cui, Lu; Wang, Hong; Xin, Baifu; Mao, Guijie

    2017-10-01

    Ultrafine nanocrystals of γ-gallium oxide (γ-Ga2O3) were rapidly synthesized via microwave hydrothermal method at 140 °C, in which Ga(NO3)3 was used as the gallium source and urea was the precipitant. The samples were characterized by X-ray diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV-Vis), transmission electron microscopy (TEM), nitrogen physisorption and photoluminescence spectroscopy (PL). The crystallite size of ultrafine spinel γ-Ga2O3 was in the range from 4 to 5 nm and the optical bandgap was 4.61 eV. To improve the crystallinity, the ultrafine γ-Ga2O3 nanocrystals were calcined at 300-700 °C further. The ultrafine γ-Ga2O3 calcined at 500 °C (calcined-γ-Ga2O3) still remained the metastable γ-phase with relatively high crystallinity and the crystallite size around 5-7 nm. Photocatalytic performances of the synthesized samples were also evaluated by the degradation of rhodamine B (RhB). Results revealed that the ultrafine γ-Ga2O3 and the calcined-γ-Ga2O3 samples exhibited high photocatalytic efficiencies of 68.2 and 90.7%, respectively.

  10. EXAFS analysis of cations distribution in structure of Co1-xNixFe2O4 nanoparticles obtained by hydrothermal method in aloe vera extract solution

    Science.gov (United States)

    Wongpratat, Unchista; Maensiri, Santi; Swatsitang, Ekaphan

    2016-09-01

    Effect of cations distribution upon EXAFS analysis on magnetic properties of Co1-xNixFe2O4 (x = 0, 0.25, 0.50, 0.75 and 1.0) nanoparticles prepared by the hydrothermal method in aloe vera extract solution were studied. XRD analysis confirmed a pure phase of cubic spinel ferrite of all samples. Changes in lattice parameter and particle size depended on the Ni content with partial substitution and site distributions of Co2+, Ni2+ ions of different ionic radii at both tetrahedral and octahedral sites in the crystal structure. Particle sizes of samples estimated by TEM images were found to be in the range of 10.87-62.50 nm. The VSM results at room temperature indicated the ferrimagnetic behavior of all samples. Superparamagnetic behavior was observed in NiFe2O4 sample. The coercivity (Hc) and remanance (Mr) values were related to the particle sizes of samples. The saturation magnetization (Ms) was increased by a factor of 1.4 to a value of 57.57 emu/g, whereas the coercivity (Hc) was decreased by a factor of 20 to a value of 63.15 Oe for a sample with x = 0.75. In addition to the cations distribution, the increase of aspect ratio (surface to volume ratio) due to the decrease of particle size could significantly affect the magnetic properties of the materials.

  11. Effects of ZnO Seed Layers Prepared with Various Precursor Concentrations on Structural and Defect Emission Properties of ZnO Nanorods Grown by Hydrothermal Method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Soaram; Nam, Giwoong; Leem, Jae-Young; Kim, Yangsoo [Inje University, Gimhae (Korea, Republic of); Kim, Ghun Sik; Yoon, Sung Pil [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

    2013-07-15

    ZnO nanorods were grown by a hydrothermal method on ZnO seed layers that had previously been prepared from solutions containing various precursor concentrations. The effects of the ZnO seed layers prepared with various precursor concentrations on the structural and defect emissions of the ZnO nanorods were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) spectroscopy. The surface morphology of the ZnO seed layers changed with an increasing precursor concentration, and the diameters and densities of the ZnO nanorods depended on the morphologies of the ZnO seed layers. The ZnO seed layers prepared with various precursor concentrations affected the residual stress in the nanorods grown on the seed layers, the intensity and full widths at half maximum of the 2-theta angle in the XRD spectra for the nanorods, and the intensity and position of the defect emission peak in deep-level emission (DLE) PL spectra for the ZnO nanorods.

  12. Phase transformation and spectroscopic adjustment of Gd{sub 2}O{sub 3}:Eu{sup 3+} synthesized by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zijun; Wang, Pei; Zhong, Jiuping, E-mail: zhongjp@mail.sysu.edu.cn; Liang, Hongbin; Wang, Jing

    2014-08-01

    The microcrystalline Gd{sub 2}O{sub 3}:Eu{sup 3+} phosphors were synthesized by the hydrothermal method with post annealing treatment. The powder X-ray diffraction (XRD) indicated the phase transformation from cubic to monoclinic occurred at about 1673 K. The morphologies and sizes were characterized by scanning electron microscopy (SEM). It was found that the morphology of Gd{sub 2}O{sub 3}:Eu{sup 3+} was altered from nanorod to microparticle as the phase changed from cubic to monoclinic. In order to evaluate the effects of sites and phases on luminescence behaviors, the photoluminescence (PL) properties of both phases were investigated. Dominant red emission was observed due to an efficient energy transfer among the sites as well as the strong excitation of O{sup 2−}–Eu{sup 3+} charge transfer band. It was calculated that the monoclinic structure has a higher degree of distortion. More importantly, the phase transformation resulted in the red shift of the strongest emission peak of Eu{sup 3+} from 610.5 to 622.5 nm, closer to the optical transmission window for bioimaging. - Highlights: • Raising annealing temperature induces phase transformation from cubic to monoclinic. • Different phases and sites lead to distinct photoluminescence properties. • Monoclinic structure has higher degree of distortion and it is calculated. • Monoclinic phase emitting at longer wavelength is proposed for bioimaging.

  13. Synthesis of LiFePO4/Li2SiO3/reduced Graphene Oxide (rGO) Composite via Hydrothermal Method

    Science.gov (United States)

    Arifin, M.; Iskandar, F.; Aimon, A. H.; Munir, M. M.; Nuryadin, B. W.

    2016-08-01

    LiFePO4 is a type of cathode active material used for lithium ion batteries. It has a high electrochemical performance. However, it suffers from certain disadvantages such as a very low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to increase the conductivity of LiFePO4. We have investigated the addition of Li2SiO3 and reduced graphene oxide (rGO) to LiFePO4. The objective of this research was to synthesize LiFePO4/Li2SiO3/rGO via hydrothermal method. Fourier transform infrared spectroscopy (FTIR) measurement showed that the peaks corresponded to the vibration of LiFePO4/Li2SiO3. Further, X-ray diffraction (XRD) measurement confirmed a single phase of LiFePO4. Finally, scanning electron microscopy (SEM) images showed that rGO was distributed on the LiFePO4/Li2SiO3 structure.

  14. Synthesis of LiFePO4/Li2SiO3/reduced Graphene Oxide (rGO) Composite via Hydrothermal Method

    International Nuclear Information System (INIS)

    Arifin, M; Iskandar, F; Aimon, A H; Munir, M M; Nuryadin, B W

    2016-01-01

    LiFePO 4 is a type of cathode active material used for lithium ion batteries. It has a high electrochemical performance. However, it suffers from certain disadvantages such as a very low intrinsic electronic conductivity and low ionic diffusion. This study was conducted to increase the conductivity of LiFePO4. We have investigated the addition of Li2SiO3 and reduced graphene oxide (rGO) to LiFePO4. The objective of this research was to synthesize LiFePO 4 /Li 2 SiO 3 /rGO via hydrothermal method. Fourier transform infrared spectroscopy (FTIR) measurement showed that the peaks corresponded to the vibration of LiFePO 4 /Li 2 SiO 3 . Further, X-ray diffraction (XRD) measurement confirmed a single phase of LiFePO4. Finally, scanning electron microscopy (SEM) images showed that rGO was distributed on the LiFePO 4 /Li 2 SiO 3 structure. (paper)

  15. Large-scale synthesis of double cauliflower-like Sb{sub 2}S{sub 3} microcrystallines by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lei [Key Laboratory for Soft Chemistry and Functional Materials, Ministry of Education (China); Xu, Hanyue [School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Han, Qiaofeng, E-mail: hanqiaofeng@njust.edu.cn [Key Laboratory for Soft Chemistry and Functional Materials, Ministry of Education (China); Wang, Xin [Key Laboratory for Soft Chemistry and Functional Materials, Ministry of Education (China)

    2013-09-25

    Highlights: •Highly uniform double cauliflower-like Sb{sub 2}S{sub 3} particles were synthesized via hydrothermal method. •Influence of reaction conditions on the morphology of the products was discussed. •Double cauliflower-like Sb{sub 2}S{sub 3} superstructures revealed broad spectrum response. -- Abstract: The double cauliflower-like Sb{sub 2}S{sub 3} superstructures assembled by nanorods were prepared using SbCl{sub 3} and Na{sub 2}S⋅9H{sub 2}O as raw materials, dodecyltrimethylammonium bromide (DTAB, C{sub 15}H{sub 31}BrN) as surfactant under acidic condition at 180 °C for 30 h. The structure, morphology and composition of the product were characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and energy diffraction spectroscopy (EDS). The effect of reaction conditions including temperature, reaction time and surfactants on the sample morphology was discussed and a possible mechanism for the formation of cauliflower-like Sb{sub 2}S{sub 3} was proposed. The cauliflower-like Sb{sub 2}S{sub 3} microcrystallines revealed broad spectrum response, which may have a good application prospect in solar energy utilization and photoelectric conversion fields.

  16. Hydrothermal liquefaction of biomass

    DEFF Research Database (Denmark)

    Toor, Saqib; Rosendahl, Lasse; Rudolf, Andreas

    2011-01-01

    This article reviews the hydrothermal liquefaction of biomass with the aim of describing the current status of the technology. Hydrothermal liquefaction is a medium-temperature, high-pressure thermochemical process, which produces a liquid product, often called bio-oil or bi-crude. During...... the hydrothermal liquefaction process, the macromolecules of the biomass are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive and can recombine into larger ones. During this process, a substantial part of the oxygen in the biomass is removed...... by dehydration or decarboxylation. The chemical properties of bio-oil are highly dependent of the biomass substrate composition. Biomass constitutes of various components such as protein; carbohydrates, lignin and fat, and each of them produce distinct spectra of compounds during hydrothermal liquefaction...

  17. Practical methods for exposure control/management at nuclear facilities

    International Nuclear Information System (INIS)

    Twiggs, J.A.

    1991-01-01

    Exposure management/reduction is very important to Duke Power Company. Practical exposure control/reduction techniques applied to their reactor vessel head disassembly outage activity have consistently reduced personnel exposure for this task. The following exposure control methods have worked for use and will be the industry's direction for the 1990's. A summary of these methods includes: (a) move the responsibility of exposure management from the Radiation Protection group to the Maintenance group; (b) reduce area source term by removal of source; (c) improve working environments in radiation areas by minimizing protective clothing usage; and (d) maximize the use of electronic instruments to allow remote monitoring

  18. Learning Method, Facilities And Infrastructure, And Learning Resources In Basic Networking For Vocational School

    OpenAIRE

    Pamungkas, Bian Dwi

    2017-01-01

    This study aims to examine the contribution of learning methods on learning output, the contribution of facilities and infrastructure on output learning, the contribution of learning resources on learning output, and the contribution of learning methods, the facilities and infrastructure, and learning resources on learning output. The research design is descriptive causative, using a goal-oriented assessment approach in which the assessment focuses on assessing the achievement of a goal. The ...

  19. Economies of using seismic experience data qualification methods at Department of Energy facilities

    International Nuclear Information System (INIS)

    Loceff, F.; Antaki, G.; Goen, L.

    1995-01-01

    This paper summarizes the implementation of the seismic qualification of existing equipment using experience data techniques. The emphasis is on the economies of this approach compared with standard qualification methods of analysis and testing or replacement with qualified equipment. Seismic qualification of existing equipment using experience data is a technical necessity and is the most economically attractive of the options. Representative costs for seismic qualification at two facilities show costs are substantially lower than the costs for qualification using conventional methods. Because of the experience to date, the authors recommend that the Department of Energy continue to sponsor the Existing Facilities Program for applying qualification using experience data techniques at DOE facilities

  20. Pretreatment methods to obtain pumpable high solid loading wood–water slurries for continuous hydrothermal liquefaction systems

    DEFF Research Database (Denmark)

    Dãrãbana, Iulia-Maria; Rosendahl, Lasse Aistrup; Pedersen, Thomas Helmer

    2015-01-01

    Feedstock pretreatment is a prerequisite step for continuous processing of lignocellulosic biomass through HTL, in order to facilitate the pumpability of biomass aqueous slurries. Until now, HTL feedstock pumpability could only be achieved at solid mass content below 15%. In this work, two...... pretreatment methods to obtain wood-based slurries with more than 20% solid mass content, for continuous processing in HTL systems, are proposed. The effect of biomass particle size and pretreatment method on the feedstock pumpability is analyzed. The experimental results show that pumpable wood-based slurries...

  1. Synthetic methods for beam to beam power balancing capability of large laser facilities

    International Nuclear Information System (INIS)

    Chen Guangyu; Zhang Xiaomin; Zhao Runchang; Zheng Wanguo; Yang Xiaoyu; You Yong; Wang Chengcheng; Shao Yunfei

    2011-01-01

    To account for output power balancing capability of large laser facilities, a synthetic method with beam to beam root-mean-square is presented. Firstly, a conversion process for the facilities from original data of beam powers to regular data is given. The regular data contribute to the normal distribution approximately, and then a corresponding simple method of root-mean-square for beam to beam power balancing capability is given.Secondly, based on theory of total control charts and cause-selecting control charts, control charts with root-mean-square are established which show short-term variety of power balancing capability of the facilities. Mean rate of failure occurrence is also defined and used to describe long-term trend of global balancing capabilities of the facilities. Finally, advantages of the intuitive and efficient diagnosis for synthetic methods are illustrated by analysis of experimental data. (authors)

  2. Methods for reducing occupational exposures during the decommissioning of nuclear facilities

    International Nuclear Information System (INIS)

    1987-01-01

    The decommissioning and decontamination of nuclear facilities is a topic of great interest to many Member States of the International Atomic Energy Agency (IAEA) because of the large number of older facilities which have been or soon will be retired from service. This report is a review of the current state of knowledge concerning methods for reducing occupational exposures during the decommissioning of nuclear facilities. This report focuses on water cooled nuclear power plants but, in addition, other major nuclear facilities are briefly discussed to determine how they differ from nuclear power plants in this regard. The information presented should be useful to those responsible for or interested in designing or constructing nuclear facilities or in the planning or implementing of the decommissioning of such installations. 59 refs, 1 tab

  3. Iron insertion and hematite segregation on Fe-doped TiO2 nanoparticles obtained from sol-gel and hydrothermal methods.

    Science.gov (United States)

    Santos, Reginaldo da S; Faria, Guilherme A; Giles, Carlos; Leite, Carlos A P; Barbosa, Herbert de S; Arruda, Marco A Z; Longo, Claudia

    2012-10-24

    Iron-doped TiO(2) (Fe:TiO(2)) nanoparticles were synthesized by the sol-gel method (with Fe/Ti molar ratio corresponding to 1, 3, and 5%), followed by hydrothermal treatment, drying, and annealing. A similar methodology was used to synthesize TiO(2) and α-Fe(2)O(3) nanoparticles. For comparison, a mixture hematite/titania, with Fe/Ti = 4% was also investigated. Characterization of the samples using Rietveld refinement of X-ray diffraction data revealed that TiO(2) consisted of 82% anatase and 18% brookite; for Fe:TiO(2), brookite increased to 30% and hematite was also identified (0.5, 1.0, and 1.2 wt % for samples prepared with 1, 3, and 5% of Fe/Ti). For hematite/titania mixture, Fe/Ti was estimated as 4.4%, indicating the Rietveld method reliability for estimation of phase composition. Because the band gap energy, estimated as 3.2 eV for TiO(2), gradually ranged from 3.0 to 2.7 eV with increasing Fe content at Fe:TiO(2), it can be assumed that a Fe fraction was also inserted as dopant in the TiO(2) lattice. Extended X-ray absorption fine structure spectra obtained for the Ti K-edge and Fe K-edge indicated that absorbing Fe occupied a Ti site in the TiO(2) lattice, but hematite features were not observed. Hematite particles also could not be identified in the images obtained by transmission electron microscopy, in spite of iron identification by elemental mapping, suggesting that hematite can be segregated at the grain boundaries of Fe:TiO(2).

  4. Microwave-assisted Facile and Ultrafast Growth of ZnO Nanostructures and Proposition of Alternative Microwave-assisted Methods to Address Growth Stoppage

    Science.gov (United States)

    Rana, Abu Ul Hassan Sarwar; Kang, Mingi; Kim, Hyun-Seok

    2016-04-01

    The time constraint in the growth of ZnO nanostructures when using a hydrothermal method is of paramount importance in contemporary research, where a long fabrication time rots the very essence of the research on ZnO nanostructures. In this study, we present the facile and ultrafast growth of ZnO nanostructures in a domestic microwave oven within a pressurized environment in just a few minutes. This method is preferred for the conventional solution-based method because of the ultrafast supersaturation of zinc salts and the fabrication of high-quality nanostructures. The study of the effect of seed layer density, growth time, and the solution’s molar concentration on the morphology, alignment, density, and aspect ratio of ZnO nanorods (ZNRs) is explored. It is found in a microwave-assisted direct growth method that ~5 mins is the optimum time beyond which homogeneous nucleation supersedes heterogeneous nucleation, which results in the growth stoppage of ZNRs. To deal with this issue, we propound different methods such as microwave-assisted solution-replacement, preheating, and PEI-based growth methods, where growth stoppage is addressed and ZNRs with a high aspect ratio can be grown. Furthermore, high-quality ZnO nanoflowers and ZnO nanowalls are fabricated via ammonium hydroxide treatment in a very short time.

  5. Facile Method for Fabricating Superhydrophobic Surface on Magnesium

    Energy Technology Data Exchange (ETDEWEB)

    Han, Mun Hee; Park, Yeon Hwa; Hyun, June Won; Ahn, Yong Hyun [Dankook Univ., Yongin (Korea, Republic of)

    2010-04-15

    In conclusion, we have developed a simple and inexpensive method for fabricating a superhydrophobic surface of magnesium by metal deposition and stearic acid coating. We fabricated a superhydrophobic surface on magnesium by nickel deposition and surface coating of stearic acid. The fabricated surfaces were stable against acidic and basic solutions. In recent times, technologies based on the imitation of nature have attracted considerable attention. Lotus leaves are known for their self-cleaning effect. The micrometer-scale papillae structure and the epicuticular wax on the lotus leaf contribute to this effect. In a manner similar to the self-cleaning property of lotus leaves, the wettability of solid surfaces is of great interest in daily life and industry.1-4 Wettability is controlled by both the geometrical structure of a surface and a low surface energy material coating. A superhydrophobic surface is satisfied with a water contact angle of more than 150 .deg. and a sliding angle of less than 10 .deg. On such a surface, a water drop has a perfectly spherical shape and it easily rolls off and removes deposited contaminants. A superhydrophobic surface thus protects a material from contamination, fogging, and snow deposition.

  6. Groundwater flow analysis using mixed hybrid finite element method for radioactive waste disposal facilities

    International Nuclear Information System (INIS)

    Aoki, Hiroomi; Shimomura, Masanori; Kawakami, Hiroto; Suzuki, Shunichi

    2011-01-01

    In safety assessments of radioactive waste disposal facilities, ground water flow analysis are used for calculating the radionuclide transport pathway and the infiltration flow rate of groundwater into the disposal facilities. For this type of calculations, the mixed hybrid finite element method has been used and discussed about the accuracy of ones in Europe. This paper puts great emphasis on the infiltration flow rate of groundwater into the disposal facilities, and describes the accuracy of results obtained from mixed hybrid finite element method by comparing of local water mass conservation and the reliability of the element breakdown numbers among the mixed hybrid finite element method, finite volume method and nondegenerated finite element method. (author)

  7. The IAEA review of methods of reducing occupational exposures during decommissioning of nuclear facilities

    International Nuclear Information System (INIS)

    Alejnikov, V.E.

    1986-01-01

    International interest in decommissioning has increased rapidly in the last few years because of the large number of older facilities which are or soon will be retired from service and because of the many hundreds of new facilities which have been built or planned and will eventually require decommissioning. A state-of-the-art review of methods of reducing occupational exposures during decommissioning of nuclear facilities has been prepared recently by the International Atomic Energy Agency. The report concludes that decommissioning can be carried out without unacceptable impact on man or his environment. However, additional development is required to reduce occupational exposures during decommissioning. (author)

  8. Hydrothermal Synthesized of CoMoO4 Microspheres as Excellent Electrode Material for Supercapacitor

    Science.gov (United States)

    Li, Weixia; Wang, Xianwei; Hu, Yanchun; Sun, Lingyun; Gao, Chang; Zhang, Cuicui; Liu, Han; Duan, Meng

    2018-04-01

    The single-phase CoMoO4 was prepared via a facile hydrothermal method coupled with calcination treatment at 400 °C. The structures, morphologies, and electrochemical properties of samples with different hydrothermal reaction times were investigated. The microsphere structure, which consisted of nanoflakes, was observed in samples. The specific capacitances at 1 A g-1 are 151, 182, 243, 384, and 186 F g-1 for samples with the hydrothermal times of 1, 4, 8, 12, and 24 h, respectively. In addition, the sample with the hydrothermal time of 12 h shows a good rate capability, and there is 45% retention of initial capacitance when the current density increases from 1 to 8 A g-1. The high retain capacitances of samples show the fine long-cycle stability after 1000 charge-discharge cycles at current density of 8 A g-1. The results indicate that CoMoO4 samples could be a choice of excellent electrode materials for supercapacitor.

  9. Electrical and photocatalytic properties of boron-doped ZnO nanostructure grown on PET-ITO flexible substrates by hydrothermal method

    Science.gov (United States)

    Wang, Wei; Ai, Taotao; Yu, Qi

    2017-02-01

    Boron-doped zinc oxide sheet-spheres were synthesized on PET-ITO flexible substrates using a hydrothermal method at 90 °C for 5 h. The results of X-ray diffraction and X-ray photoelectron spectroscopy indicated that the B atoms were successfully doped into the ZnO lattice, the incorporation of B led to an increase in the lattice constant of ZnO and a change in its internal stress. The growth mechanism of pure ZnO nanorods and B-doped ZnO sheet-spheres was specifically investigated. The as-prepared BZO/PET-ITO heterojunction possessed obvious rectification properties and its positive turn-on voltage was 0.4 V. The carrier transport mechanisms involved three models such as hot carrier tunneling theory, tunneling recombination, and series-resistance effect were explored. The BZO/PET-ITO nanostructures were more effective than pure ZnO to degrade the RY 15, and the degradation rate reached 41.45%. The decomposition process with BZO nanostructure followed first-order reaction kinetics. The photocurrent and electrochemical impedance spectroscopy revealed that the B-doping could promote the separation of photo-generated electron-hole pairs, which was beneficial to enhance the photocatalytic activity. The photocurrent density of B-doped and pure ZnO/PET-ITO were 0.055 mA/cm2 and 0.016 mA/cm2, respectively. The photocatalytic mechanism of the sample was analyzed by the energy band theory.

  10. Characterization and magnetic properties of SrTi{sub 1−x}Ni{sub x}O{sub 3} nanoparticles prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Karaphun, Attaphol [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Hunpratub, Sitchai; Phokha, Sumalin [Department of Physics, Faculty of Science, Rajabhat Udon Thani University, Udon Thani 41000 (Thailand); Putjuso, Thanin [Rajamangala University of Technology Rattanakosin Wang Klai Kangwon Campus, Prachuap Khiri Khan 77110 (Thailand); Swatsitang, Ekaphan, E-mail: ekaphan@kku.ac.th [Integrated Nanotechnology Research Center, Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Nanotec-KKU Center of Excellence on Advanced Nanomaterials for Energy Production and Storage, Khon Kaen 40002 (Thailand)

    2017-01-01

    SrTi{sub 1−x}Ni{sub x}O{sub 3} (x=0, 0.05, 0.10 and 0.15) nanoparticles were prepared by the hydrothermal method. All as-prepared samples were annealed at 800 °C for 3 h in argon to study the annealing effect on their magnetic properties. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray absorption near edge spectroscopy (XANES), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM) were used to study the crystalline structure, morphology, oxidation state and magnetic properties of samples. XRD results indicate a cubic perovskite structure of all samples with the impurity phase of SrCO{sub 3} in all as-prepared samples and Ni metal in annealed samples of x=0.10 and 0.15. SEM and TEM images confirmed a cubic shape for all samples with decreasing average particle sizes from 136.8±4.7 to 126.2±6.9 nm for annealed samples upon Ni doping. XANES results revealed the existence of Ni metal in sample of x=0.05 with the oxidation state of +2 for Ni ion in a SrTi{sub 0.95}Ni{sub 0.05}O{sub 3} sample. XPS results indicated the promotion of oxygen vacancies. VSM results revealed a paramagnetic behavior at room temperature of all as-prepared samples. Ni-doped samples exhibited ferromagnetic behavior after annealing in argon with the Curie temperature (T{sub C}) above 380 K for a sample with x=0.05 as shown by field cooling (FC) and zero-field cooling (ZFC) measurements. The room temperature ferromagnetism (RT-FM) of ferromagnetic samples was suggested to be originated from Ni metal and F-center exchange (FCE) mechanism due to the promotion of oxygen vacancies in the perovskite structure.

  11. Fabrication of mesoporous iron (Fe) doped copper sulfide (CuS) nanocomposite in the presence of a cationic surfactant via mild hydrothermal method for supercapacitors

    Science.gov (United States)

    Brown, J. William; Ramesh, P. S.; Geetha, D.

    2018-02-01

    We report fabrication of mesoporous Fe doped CuS nanocomposites with uniform mesoporous spherical structures via a mild hydrothermal method employing copper nitrate trihydrate (Cu (NO3).3H2O), Thiourea (Tu,Sc(NH2)2 and Iron tri nitrate (Fe(No3)3) as initial materials with cationic surfactant cetyltrimethylamoniame bromide (CTAB) as stabilizer/size controller and Ethylene glycol as solvent at 130 °C temperature. The products were characterized by XRD, SEM/EDX, TEM, FTIR and UV analysis. X-ray diffraction (XRD) spectra confirmed the Fe doped CuS nanocomposites which are crystalline in nature. EDX and XRD pattern confirmed that the product is hexagonal CuS phase. Fe doped spherical structure of CuS with grain size of 21 nm was confirmed by XRD pattern. Fe doping was identified by energy dispersive spectrometry (EDS). The Fourier-transform infrared (FTIR) spectroscopy results revealed the occurrence of active functional groups required for the reduction of copper ions. Studies showed that after a definite time relining on the chosen copper source, the obtained Fe-CuS nanocomposite shows a tendency towards self-assembly and creating mesoporous like nano and submicro structures by TEM/SAED. The achievable mechanism of producing this nanocomposite was primarily discussed. The electrochemical study confirms the pseudocapacitive nature of the CuS and Fe-CuS electrodes. The CuS and Fe-CuS electrode shows a specific capacitance of about 328.26 and 516.39 Fg-1 at a scan rate of 5 mVs-1. As the electrode in a supercapacitor, the mesoporous nanostructured Fe-CuS shows excellent capacitance characteristics.

  12. Geophysical and geochemical methods applied to investigate fissure-related hydrothermal systems on the summit area of Mt. Etna volcano (Italy)

    Science.gov (United States)

    Maucourant, Samuel; Giammanco, Salvatore; Greco, Filippo; Dorizon, Sophie; Del Negro, Ciro

    2014-06-01

    A multidisciplinary approach integrating self-potential, soil temperature, heat flux, CO2 efflux and gravity gradiometry signals was used to investigate a relatively small fissure-related hydrothermal system near the summit of Mt. Etna volcano (Italy). Measurements were performed through two different surveys carried out at the beginning and at the end of July 2009, right after the end of the long-lived 2008-2009 flank eruption and in coincidence with an increase in diffuse flank degassing related to a reactivation of the volcano, leading to the opening of a new summit vent (NSEC). The main goal was to use a multidisciplinary approach to the detection of hidden fractures in an area of evident near-surface hydrothermal activity. Despite the different methodologies used and the different geometry of the sampling grid between the surveys, all parameters concurred in confirming that the study area is crossed by faults related with the main fracture systems of the south flank of the volcano, where a continuous hydrothermal circulation is established. Results also highlighted that hydrothermal activity in this area changed both in space and in time. These changes were a clear response to variations in the magmatic system, notably to migration of magma at various depth within the main feeder system of the volcano. The results suggest that this specific area, initially chosen as the optimal test-site for the proposed approach, can be useful in order to get information on the potential reactivation of the summit craters of Mt. Etna.

  13. Facile and green synthesis of (La0.95Eu0.052O2S red phosphors with sulfate-ion pillared layered hydroxides as a new type of precursor: controlled hydrothermal processing, phase evolution and photoluminescence

    Directory of Open Access Journals (Sweden)

    Xuejiao Wang

    2014-01-01

    Full Text Available This study presents a facile and green route for the synthesis of (La0.95Eu0.052O2S red phosphors of controllable morphologies, with the sulfate-type layered hydroxides of Ln2(OH4SO4centerdot2H2O (Ln = La and Eu as a new type of precursor. The technique takes advantage of the fact that the precursor has had the exact Ln:S molar ratio of the targeted phosphor, thus saving the hazardous sulfurization reagents indispensable to traditional synthesis. Controlled hydrothermal processing at 120 °C yielded phase-pure Ln2(OH4SO4centerdot2H2O crystallites in the form of either nanoplates or microprisms, which can both be converted into Ln2O2S phosphor via a Ln2O2SO4 intermediate upon annealing in flowing H2 at a minimum temperature of ~ 700 °C. The nanoplates collapse into relatively rounded Ln2O2S particles while the microprisms retain well their initial morphologies at 1 200 °C, thus yielding two types of red phosphors. Photoluminescence excitation (PLE studies found two distinct charge transfer (CT excitation bands of O2− → Eu3+ at ~ 270 nm and S2− → Eu3+ at ~ 340 nm for the Ln2O2S phosphors, with the latter being stronger and both significantly stronger than the intrinsic intra-f transitions of Eu3+. The two types of phosphors share high similarities in the positions of PLE/PL (photoluminescence bands and both show the strongest red emission at 627 nm (5D0 → 7F2 transition of Eu3+ under S2− → Eu3+ CT excitation at 340 nm. The PLE/PL intensities show clear dependence on particle morphology and calcination temperature, which were investigated in detail. Fluorescence decay analysis reveals that the 627 nm red emission has a lifetime of ~ 0.5 ms for both types of the phosphors.

  14. Simplified static method for determining seismic loads on equipment in moderate and high hazard facilities

    International Nuclear Information System (INIS)

    Scott, M.A.; Holmes, P.A.

    1991-01-01

    A simplified static analysis methodology is presented for qualifying equipment in moderate and high-hazard facility-use category structures, where the facility use is defined in Design and Evaluation Guidelines for Department of Energy Facilities Subjected to Natural Phenomena Hazards, UCRL-15910. Currently there are no equivalent simplified static methods for determining seismic loads on equipment in these facility use categories without completing dynamic analysis of the facility to obtain local floor accelerations or spectra. The requirements of UCRL-15910 specify the use of open-quotes dynamicclose quotes analysis methods, consistent with Seismic Design Guidelines for Essential Buildings, Chapter 6, open-quotes Nonstructural Elements,close quotes TM5-809-10-1, be used for determining seismic loads on mechanical equipment and components. Chapter 6 assumes that the dynamic analysis of the facility has generated either floor response spectra or model floor accelerations. These in turn are utilized with the dynamic modification factor and the actual demand and capacity ratios to determine equipment loading. This complex methodology may be necessary to determine more exacting loads for hard to qualify equipment but does not provide a simple conservative loading methodology for equipment with ample structural capacity

  15. Stabilization of uranium hexafluoride by hydrolysis method for decommissioning of safeguard laboratory facility

    Energy Technology Data Exchange (ETDEWEB)

    Inagawa, Jun; Hotoku, Shinobu; Oda, Tetsuzo; Aoyagi, Noboru; Magara, Masaaki [Japan Atomic Energy Agency, Nuclear Science and Engineering Directorate, Tokai, Ibaraki (Japan)

    2014-03-15

    In safeguard laboratory (SGL) facility of Nuclear Science Research Institute of JAEA , uranium hexafluoride (UF{sub 6}) of enriched uranium of various enrichment was used for research and development of a spectrometric method for the determination of the enrichment of uranium in April 1983 through March 1993. After completion of this R and D, the UF{sub 6} has been stored in SGL facility. It was decided that the UF{sub 6} is carried to out of the facility, because the SGL facility will be decommissioning until March 2015. To transport and store in safety after transportation, it is necessary that the UF{sub 6} should be converted to stable chemical form. Hydrolysis of UF{sub 6} to uranyl fluoride (UO{sub 2}F{sub 2}) and evaporation to solid state were selected for the stabilization method. The equipment for hydrolysis and evaporation was installed in the SGL facility. Stabilization was operated in this equipment, and all of the UF{sub 6} in the SGL facility was converted to UO{sub 2}F{sub 2} solid state in October 2012 through August 2013. In this report, results of examination and operation for stabilization of UF{sub 6} were reported. (author)

  16. Complexing and hydrothermal ore deposition

    CERN Document Server

    Helgeson, Harold C

    1964-01-01

    Complexing and Hydrothermal Ore Deposition provides a synthesis of fact, theory, and interpretative speculation on hydrothermal ore-forming solutions. This book summarizes information and theory of the internal chemistry of aqueous electrolyte solutions accumulated in previous years. The scope of the discussion is limited to those aspects of particular interest to the geologist working on the problem of hydrothermal ore genesis. Wherever feasible, fundamental principles are reviewed. Portions of this text are devoted to calculations of specific hydrothermal equilibriums in multicompone

  17. Minimum dose method for walking-path planning of nuclear facilities

    International Nuclear Information System (INIS)

    Liu, Yong-kuo; Li, Meng-kun; Xie, Chun-li; Peng, Min-jun; Wang, Shuang-yu; Chao, Nan; Liu, Zhong-kun

    2015-01-01

    Highlights: • For radiation environment, the environment model is proposed. • For the least dose walking path problem, a path-planning method is designed. • The path-planning virtual–real mixed simulation program is developed. • The program can plan walking path and simulate. - Abstract: A minimum dose method based on staff walking road network model was proposed for the walking-path planning in nuclear facilities. A virtual–reality simulation program was developed using C# programming language and Direct X engine. The simulation program was used in simulations dealing with virtual nuclear facilities. Simulation results indicated that the walking-path planning method was effective in providing safety for people walking in nuclear facilities

  18. Methods of sampling airborne fungi in working environments of waste treatment facilities.

    Science.gov (United States)

    Černá, Kristýna; Wittlingerová, Zdeňka; Zimová, Magdaléna; Janovský, Zdeněk

    2016-01-01

    The objective of the present study was to evaluate and compare the efficiency of a filter based sampling method and a high volume sampling method for sampling airborne culturable fungi present in waste sorting facilities. Membrane filters method was compared with surface air system method. The selected sampling methods were modified and tested in 2 plastic waste sorting facilities. The total number of colony-forming units (CFU)/m3 of airborne fungi was dependent on the type of sampling device, on the time of sampling, which was carried out every hour from the beginning of the work shift, and on the type of cultivation medium (p airborne fungi ranged 2×102-1.7×106 CFU/m3 when using the membrane filters (MF) method, and 3×102-6.4×104 CFU/m3 when using the surface air system (SAS) method. Both methods showed comparable sensitivity to the fluctuations of the concentrations of airborne fungi during the work shifts. The SAS method is adequate for a fast indicative determination of concentration of airborne fungi. The MF method is suitable for thorough assessment of working environment contamination by airborne fungi. Therefore we recommend the MF method for the implementation of a uniform standard methodology of airborne fungi sampling in working environments of waste treatment facilities. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  19. Use of the event tree method for evaluate the safety of radioactive facilities

    International Nuclear Information System (INIS)

    Hernandez S, A.; Cornejo D, N.; Callis F, E.

    2006-01-01

    The work shows the validity of the use of Trees of Events like a quantitative method appropriate to carry out evaluations of radiological safety. Its were took like base the evaluations of safety of five Radiotherapy Departments, carried out in the mark of the process of authorization of these facilities. The risk values were obtained by means of the combination of the probabilities of occurrence of the events with its consequences. The use of the method allowed to suggest improvements to the existent safety systems, as well as to confirm that the current regulator requirements for this type of facilities to lead to practices with acceptable risk levels. (Author)

  20. Development of partitioning method : cold experiment with partitioning test facility in NUCEF (I)

    International Nuclear Information System (INIS)

    Yamaguchi, Isoo; Morita, Yasuji; Kondo, Yasuo

    1996-03-01

    A test facility in which about 1.85 x 10 14 Bq of high-level liquid waste can be treated has been completed in 1994 at Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF) for research and development of Partitioning Method. The outline of the partitioning test facility and support equipments for it which were design terms, constructions, arrangements, functions and inspections were given in JAERI-Tech 94-030. The present report describes the results of the water transfer test and partitioning tests, which are methods of precipitation by denitration, oxalate precipitation, solvent extraction, and adsorption with inorganic ion exchanger, using nitric acid to master operation method of the test facility. As often as issues related to equipments occurred during the tests, they were improved. As to issues related to processes such as being stopped up of columns, their measures of solution were found by testing in laboratories. They were reflected in operation of the Partitioning Test Facility. Their particulars and improving points were described in this report. (author)

  1. Hydrothermal conversion of biomass

    NARCIS (Netherlands)

    Knezevic, D.

    2009-01-01

    This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of

  2. Comparison and discussion of two types of threat (Hazard) categorization method for nuclear facilities

    International Nuclear Information System (INIS)

    Tang, Rongyao; Xu, Xiaoxiao; Zhang, Jiangang; Zhao, Bin

    2008-01-01

    The emergency threat categorization method suggested by international atomic energy agency (IAEA) and hazard categorization standard by the Department of Energy of United States (USDOE) for nuclear facilities are compared and discussed in this paper. The research shows the two types of categorization method for nuclear facility are similar, though each has its own speciality. The categorization method suggested by IAEA is quite completed and sound in scientific basis. The thresholds of radioactive material are connected with the quantity of dangerous source, and the latest radiobiological effect research results are taken in setting the thresholds. While the main purpose is put on emergency management, some of the categorization criteria do not fit for safety surveillance of nuclear facilities. The categorization method of DOE is advanced in its operability, and it fits for safety surveillance. The disadvantage is that the thresholds of radioactive material need to be updated because the parameters used in calculation is outdated, and also the threshold of category 3 is somewhat disputable for many reasons. We should take advantage of both methods and adjust the standards according to the application purpose while establishing the categorization standard of nuclear facilities in China. (author)

  3. Validation of cleaning method for various parts fabricated at a Beryllium facility

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Cynthia M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-15

    This study evaluated and documented a cleaning process that is used to clean parts that are fabricated at a beryllium facility at Los Alamos National Laboratory. The purpose of evaluating this cleaning process was to validate and approve it for future use to assure beryllium surface levels are below the Department of Energy’s release limits without the need to sample all parts leaving the facility. Inhaling or coming in contact with beryllium can cause an immune response that can result in an individual becoming sensitized to beryllium, which can then lead to a disease of the lungs called chronic beryllium disease, and possibly lung cancer. Thirty aluminum and thirty stainless steel parts were fabricated on a lathe in the beryllium facility, as well as thirty-two beryllium parts, for the purpose of testing a parts cleaning method that involved the use of ultrasonic cleaners. A cleaning method was created, documented, validated, and approved, to reduce beryllium contamination.

  4. Synthesis RMn{sub 2}O{sub 5} (R = Gd and Sm) nano- and microstructures by a simple hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Gangqiang, E-mail: zgq2006@snnu.edu.cn [School of Physics and Information Technology, Shaanxi Normal University, Xi' an 710062 (China); Liu Peng [School of Physics and Information Technology, Shaanxi Normal University, Xi' an 710062 (China); Hojamberdiev, Mirabbos [Shaanxi Key Laboratory of Nano-materials and Technology, Xi' an University of Architecture and Technology, Xi' an 710055 (China); Ge Bao [School of Physics and Information Technology, Shaanxi Normal University, Xi' an 710062 (China); Liu Yun; Miao Hongyan; Tan Guoqiang [College of Materials Science and Engineering, Shaanxi University of Science and Technology, Xi' an 710021 (China)

    2009-12-15

    Single-phase RMn{sub 2}O{sub 5} (R = Gd and Sm) nano- and microstructures have been successfully synthesized via a simple hydrothermal process at 250 deg. C for 24 h using NaOH as mineralizer. X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and selective area electron diffraction patterns (SAED) were used to characterize the as-synthesized GdMn{sub 2}O{sub 5} and SmMn{sub 2}O{sub 5} samples. The effect of NaOH concentration and the molar ratio of Mn{sup 2+}/Mn{sup 7+} on the morphology and size of the final products was studied, and a possible formation mechanism of RMn{sub 2}O{sub 5} (R = Gd and Sm) nanoplates and nanorods under hydrothermal conditions was proposed.

  5. Systematic analysis method for radioactive wastes generated from nuclear research facilities

    International Nuclear Information System (INIS)

    Kameo, Yutaka; Ishimori, Ken-ichiro; Haraga, Tomoko; Shimada, Asako; Katayama, Atsushi; Nakashima, Mikio; Takahashi, Kuniaki

    2011-01-01

    Analytical methods have been developed for the simple and rapid determination of radioactive nuclides, which are selected as important nuclides for the safety assessment of the disposal of wastes generated from research facilities. We advanced the development of a high-efficiency nondestructive measurement technique for γ-ray-emitting nuclides, simple and rapid methods for the pretreatment of hard-to-dissolve samples and subsequent radiochemical separation, and rapid determination methods for long-lived nuclides. In order to establish a system to analyze the important nuclides in various kinds of sample, actual radioactive wastes such as concentrated liquid waste, activated concrete, and metal pipes were analyzed by the present method. The results showed that the present method was well suited for a rapid and simple determination of low-level radioactive wastes generated from research facilities. (author)

  6. Robust Mesoporous CoMo/γ-Al2O3 Catalysts from Cyclodextrin-Based Supramolecular Assemblies for Hydrothermal Processing of Microalgae: Effect of the Preparation Method.

    Science.gov (United States)

    Bleta, Rudina; Schiavo, Benedetto; Corsaro, Natale; Costa, Paula; Giaconia, Alberto; Interrante, Leonardo; Monflier, Eric; Pipitone, Giuseppe; Ponchel, Anne; Sau, Salvatore; Scialdone, Onofrio; Tilloy, Sébastien; Galia, Alessandro

    2018-04-18

    Hydrothermal liquefaction (HTL) is a promising technology for the production of biocrude oil from microalgae. Although this catalyst-free technology is efficient under high-temperature and high-pressure conditions, the biocrude yield and quality can be further improved by using heterogeneous catalysts. The design of robust catalysts that preserve their performance under hydrothermal conditions will be therefore very important in the development of biorefinery technologies. In this work, we describe two different synthetic routes (i.e., impregnation and cyclodextrin-assisted one-pot colloidal approach), for the preparation in aqueous phase of six high surface area CoMo/γ-Al 2 O 3 catalysts. Catalytic tests performed on the HTL of Nannochloropsis gaditana microalga indicate that solids prepared by the one-pot colloidal approach show higher hydrothermal stability and enhanced biocrude yield with respect to the catalyst-free test. The positive effect of the substitution of the block copolymer Tetronic T90R4 for Pluronic F127 in the preparation procedure was evidenced by diffuse reflectance UV-visible spectroscopy, X-ray diffraction, N 2 -adsorption-desorption, and H 2 -temperature-programmed reduction measurements and confirmed by the higher quality of the obtained biocrude, which exhibited lower oxygen content and higher-energy recovery equal to 62.5% of the initial biomass.

  7. Methods for nondestructive assay holdup measurements in shutdown uranium enrichment facilities

    International Nuclear Information System (INIS)

    Hagenauer, R.C.; Mayer, R.L. II.

    1991-09-01

    Measurement surveys of uranium holdup using nondestructive assay (NDA) techniques are being conducted for shutdown gaseous diffusion facilities at the Oak Ridge K-25 Site (formerly the Oak Ridge Gaseous Diffusion Plant). When in operation, these facilities processed UF 6 with enrichments ranging from 0.2 to 93 wt % 235 U. Following final shutdown of all process facilities, NDA surveys were initiated to provide process holdup data for the planning and implementation of decontamination and decommissioning activities. A three-step process is used to locate and quantify deposits: (1) high-resolution gamma-ray measurements are performed to generally define the relative abundances of radioisotopes present, (2) sizable deposits are identified using gamma-ray scanning methods, and (3) the deposits are quantified using neutron measurement methods. Following initial quantitative measurements, deposit sizes are calculated; high-resolution gamma-ray measurements are then performed on the items containing large deposits. The quantitative estimates for the large deposits are refined on the basis of these measurements. Facility management is using the results of the survey to support a variety of activities including isolation and removal of large deposits; performing health, safety, and environmental analyses; and improving facility nuclear material control and accountability records. 3 refs., 1 tab

  8. Novel S-35 Intrinsic Tracer Method for Determining Groundwater Travel Time near Managed Aquifer Recharge Facilities

    Science.gov (United States)

    Urióstegui, S. H.; Bibby, R. K.; Esser, B. K.; Clark, J. F.

    2013-12-01

    Identifying groundwater travel times near managed aquifer recharge (MAR) facilities is a high priority for protecting public and environmental health. For MAR facilities in California that incorporate tertiary wastewater into their surface-spreading recharge practices, the target subsurface residence time is >9 months to allow for the natural inactivation and degradation of potential contaminants (less time is needed for full advanced treated water). Established intrinsic groundwater tracer techniques such as tritium/helium-3 dating are unable to resolve timescales of method using a naturally occurring radioisotope of sulfur, sulfur-35 (S-35). After its production in the atmosphere by cosmic ray interaction with argon, S-35 enters the hydrologic cycle as dissolved sulfate through precipitation The short half-life of S-35 (3 months) is ideal for investigating recharge and transport of MAR groundwater on the method, however, has not been applied to MAR operations because of the difficulty in measuring S-35 with sufficient sensitivity in high-sulfate waters. We have developed a new method and have applied it at two southern California MAR facilities where groundwater travel times have previously been characterized using deliberate tracers: 1) Rio Hondo Spreading Grounds in Los Angeles County, and 2) Orange County Groundwater Recharge Facilities in Orange County. Reasonable S-35 travel times of method also identified seasonal patterns in subsurface travel times, which may not be revealed by a deliberate tracer study that is dependent on the hydrologic conditions during the tracer injection period.

  9. Automatic methods for processing track-detector data at the PAVICOM facility

    International Nuclear Information System (INIS)

    Aleksandrov, A.B.; Goncharova, L.A.; Polukhina, N.G.; Fejnberg, E.L.; Davydov, D.A.; Publichenko, P.A.; Roganova, T.M.

    2007-01-01

    New automatic methods essentially simplify and hasten the data treatment of tracking detectors. It allows handling big data files and appreciably improves their statistics; this fact predetermines an elaboration of new experiments, which suppose to use large volume targets, emulsive and solid-state large square tracking detectors. Thereupon the problem of training competent physicists able to work on modern automatic equipment is very relevant. About ten Moscow students working in LPI at PAVICOM facility master new methods every year. Most of the students working in high-energy physics take the print only about archaic hand methods of data handling from tracking detectors. In 2005 on the base of the PAVICOM facility and physics training of the MSU a new educational work for determination of the energy of neutrons passing through nuclear emulsion, which lets students acquire a base habit of data handling from tracking detectors using an automatic facility, was prepared; it can be included in the training process for students of any physical faculty. Specialists mastering methods of an automatic handling by the simple and obvious example of tracking detectors will be able to use their knowledge in various areas of science and techniques. The organization of upper division courses is a new additional aspect of using the PAVICOM facility described in an earlier paper [4

  10. The use of music in aged care facilities: A mixed-methods study.

    Science.gov (United States)

    Garrido, Sandra; Dunne, Laura; Perz, Janette; Chang, Esther; Stevens, Catherine J

    2018-02-01

    Music is frequently used in aged care, being easily accessible and cost-effective. Research indicates that certain types of musical engagement hold greater benefits than others. However, it is not clear how effectively music is utilized in aged care facilities and what the barriers are to its further use. This study used a mixed-methods paradigm, surveying 46 aged care workers and conducting in-depth interviews with 5, to explore how music is used in aged care facilities in Australia, staff perceptions of the impact of music on residents, and the barriers to more effective implementation of music in aged care settings.

  11. Facile method for CLSM imaging unfunctionalized Au nanoparticles through fluorescent channels

    International Nuclear Information System (INIS)

    Yuan Lan; Wei Wei; Li Juan; Sun, Zhiwei; Wang Hongfang; Zhang Xiuzhi; Chen Yueyue

    2009-01-01

    The microscopic visualization of metal nanoparticles has become a useful tool for the investigation of their applications in cell labeling and the study of their bio-effects. In the current study, we have developed a facile method with confocal laser scanning microscope (CLSM) to observe unfunctionalized Au nanoparticles through fluorescent channels. The sharp reflected signal and photostable property of the metal nanoparticles makes the present method very ideal for fluorescent co-localization, real-time imaging, and further quantitative analysis.

  12. Field and laboratory test methods for geomembranes during waste management facility construction

    International Nuclear Information System (INIS)

    Allen, S.R.; McCutchan, J.B.

    1991-01-01

    Hazardous waste management facilities are required to use approved lining and leak detection systems to prevent the migration of waste into the environment. Synthetic flexible membrane liners (FMLs) have effectively served as the critical barrier for waste containment and fluid migration. The U.S. EPA has established minimum technology requirements for the construction of lined facilities that include detailed and documented Construction Quality Assurance (CQA) plans. The U.S. EPA (EPA) recognizes that CQA during field construction is imperative for successful completion of project work and long-term facility operation. This paper discusses the importance of CQA during FML installation and the practical aspects of implementing a successful CQA program. Standard methods used for FML evaluation, in both the field and laboratory, are discussed and specific aspects of seam testing and data evaluation are addressed. The general importance of comprehensive definition of geomembrane seam field failures is strongly emphasized so that an appropriate response to test failures can be recommended

  13. Preventing Airborne Disease Transmission: Review of Methods for Ventilation Design in Health Care Facilities

    Science.gov (United States)

    Aliabadi, Amir A.; Rogak, Steven N.; Bartlett, Karen H.; Green, Sheldon I.

    2011-01-01

    Health care facility ventilation design greatly affects disease transmission by aerosols. The desire to control infection in hospitals and at the same time to reduce their carbon footprint motivates the use of unconventional solutions for building design and associated control measures. This paper considers indoor sources and types of infectious aerosols, and pathogen viability and infectivity behaviors in response to environmental conditions. Aerosol dispersion, heat and mass transfer, deposition in the respiratory tract, and infection mechanisms are discussed, with an emphasis on experimental and modeling approaches. Key building design parameters are described that include types of ventilation systems (mixing, displacement, natural and hybrid), air exchange rate, temperature and relative humidity, air flow distribution structure, occupancy, engineered disinfection of air (filtration and UV radiation), and architectural programming (source and activity management) for health care facilities. The paper describes major findings and suggests future research needs in methods for ventilation design of health care facilities to prevent airborne infection risk. PMID:22162813

  14. Cutting Method of the CAD model of the Nuclear facility for Dismantling Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ikjune; Choi, ByungSeon; Hyun, Dongjun; Jeong, KwanSeong; Kim, GeunHo; Lee, Jonghwan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Current methods for process simulation cannot simulate the cutting operation flexibly. As is, to simulate a cutting operation, user needs to prepare the result models of cutting operation based on pre-define cutting path, depth and thickness with respect to a dismantle scenario in advance. And those preparations should be built again as scenario changes. To be, user can change parameters and scenarios dynamically within a simulation configuration process so that the user saves time and efforts to simulate cutting operations. This study presents the methodology of cutting operation which can be applied to all the procedure in the simulation of dismantling of nuclear facilities. We developed the cutting simulation module for cutting operation in the dismantling of the nuclear facilities based on proposed cutting methodology. We defined the requirement of model cutting methodology based on the requirement of the dismantling of nuclear facilities. And we implemented cutting simulation module based on API of the commercial CAD system.

  15. Quantification of porosity evolution from unaltered to propylitic-altered granites: the 14C-PMMA method applied on the hydrothermal system of Lavras do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Everton M. Bongiolo

    2007-09-01

    Full Text Available This work is an application of the 14C-Polymethylmethacrylate method to compare the porosity evolution between unaltered and propylitic-altered granites, using samples from Lavras do Sul region, Brazil. This method, when coupled with optical and electronic petrography has the advantage over other methods to provide the quantification and identification of total and local porosity of rocks. From petrographic observations, different kinds of porous zones were identified and quantified (microfractures, grain boundaries, alteration of minerals, etc. Results show that unaltered granites have 0.5 to 0.6% porosity and propylitic-altered ones have 1.7 to 1.8% porosity, even between samples with different textures. Porosity of altered rocks increases mainly due to higher porosity of neoformed chlorite, calcite, sericite and microfractures. Field observations show that later phyllic alteration halos are wider in equigranular than in porphyritic granites, which could not be explained by different original porosity between those rocks. The observed differences of phyllic halos diffusion were controlled by structural and fluid/rock ratio variations between the equigranular and porphyritic granitic facies during the later hydrothermal stage.Este trabalho é uma aplicação do método 14C-polimetilmetacrilato na comparação da evolução da porosidade entre granitos não alterados e propilitizados, utilizando amostras da região de Lavras do Sul, Brasil. Este método, quando associado a análises por petrografia ótica, eletrônica e processamento digital de imagens tem a vantagem de fornecer, além da porosidade total, a quantificação e identificação da porosidade em locais específicos das rochas. A partir da petrografia foi possível identificar e quantificar os diferentes tipos de poros presentes nas rochas (microfraturas, limites de grãos, alteração de minerais, etc. Os resultados mostram que granitos não alterados têm porosidade de 0,5 a 0,6% e

  16. Photoelectrochemical and structural properties of TiO.sub.2./sub. nanotubes and nanorods grown on FTO substrate: Comparative study between electrochemical anodization and hydrothermal method used for the nanostructures fabrication

    Czech Academy of Sciences Publication Activity Database

    Kmentová, H.; Kment, Š.; Wang, L.; Paušová, Š.; Václavů, Tereza; Kužel, R.; Han, H.; Hubička, Z.; Zlámal, M.; Olejníček, J.; Čada, M.; Krysa, J.; Zbořil, R.

    2016-01-01

    Roč. 287, Jun (2016), s. 130-136 ISSN 0920-5861 R&D Projects: GA MŠk LO1603; GA ČR(CZ) GA14-03276S EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : 1D nanostructures * nanorods * nanotubes * hydrothermal method * self-organized anodization * photoelectrochemical water splitting * photocurrents * electron lifetime Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 4.636, year: 2016

  17. Evaluation of methods for seismic analysis of nuclear fuel reprocessing and fabrication facilities

    International Nuclear Information System (INIS)

    Arthur, D.F.; Dong, R.G.; Murray, R.C.; Nelson, T.A.; Smith, P.D.; Wight, L.H.

    1978-01-01

    Methods of seismic analysis for critical structures and equipment in nuclear fuel reprocessing plants (NFRPs) and mixed oxide fuel fabrication plants (MOFFPs) are evaluated. The purpose of this series of reports is to provide the NRC with a technical basis for assessing seismic analysis methods and for writing regulatory guides in which methods ensuring the safe design of nuclear fuel cycle facilities are recommended. The present report evaluates methods of analyzing buried pipes and wells, sloshing effects in large pools, earth dams, multiply supported equipment, pile foundations, and soil-structure interactions

  18. High activity of Ag-doped Cd0.1Zn0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

    Directory of Open Access Journals (Sweden)

    Leny Yuliati

    2014-05-01

    Full Text Available Background: The hydrothermal method was used as a new approach to prepare a series of Ag-doped Cd0.1Zn0.9S photocatalysts. The effect of Ag doping on the properties and photocatalytic activity of Cd0.1Zn0.9S was studied for the hydrogen production from water reduction under visible light irradiation.Results: Compared to the series prepared by the co-precipitation method, samples prepared by the hydrothermal method performed with a better photocatalytic activity. The sample with the optimum amount of Ag doping showed the highest hydrogen production rate of 3.91 mmol/h, which was 1.7 times higher than that of undoped Cd0.1Zn0.9S. With the Ag doping, a red shift in the optical response was observed, leading to a larger portion of the visible light absorption than that of without doping. In addition to the larger absorption in the visible-light region, the increase in photocatalytic activity of samples with Ag doping may also come from the Ag species facilitating electron–hole separation.Conclusion: This study demonstrated that Ag doping is a promising way to enhance the activity of Cd0.1Zn0.9S photocatalyst.

  19. Hydrothermal Synthesis and Electrochemical Performance of Manganese Oxide (Na-OMS-2) Nanorods.

    Science.gov (United States)

    Zhang, Qing; Xu, Shan; Zheng, Hao; Luo, Zhaohui; Liu, Kang; Wang, Wei; Li, Guohua; Wang, Shiquan; Liu, Jianwen; Feng, Chuanqi

    2017-02-01

    Sodium octahedral molecular sieve nanorods (Na-OMS-2) were prepared through a facile hydrothermal method. The effects of reaction temperature and duration on particle sizes of the products were investigated. The electrochemical performance of samples was studied by constant current charge–discharge tests as cathode material for Li-ion batteries (LIBs). The initial discharge capacity of Na-OMS-2 is 123.4 mAh g−1 and the capacity retention was 123.9 mAh g−1 after 100 cycles. The result demonstrates that Na-OMS-2 cathode material behaves a good cycling stability.

  20. Hydrothermal Cold Sintering

    Science.gov (United States)

    Kang, Xiaoyu

    Solid state sintering transforms particle compact to a physically robust and dense polycrystalline monolith driven by reduction of surface energy and curvature. Since bulk diffusion is required for neck formation and pore elimination, sintering temperature about 2/3 of melting point is needed. It thus places limitations for materials synthesis and integration, and contributes to significant energy consumption in ceramic processing. Furthermore, since surface transport requires lower temperature than bulk processes, grain growth is often rapid and can be undesired for physical properties. For these reasons, several techniques have been developed including Liquid Phase Sintering (LPS), Hot Pressing (HP) and Field Assisted Sintering Technique (FAST), which introduce either viscous melt, external pressure or electric field to speed up densification rates at lower temperature. However, because of their inherent reliability on bulk diffusion, temperatures required are often too high for integrating polymers and non-noble metals. Reduction of sintering temperature below 400 °C would require a different densification mechanism that is based on surface transport with external forces to drive volume shrinkage. Densification method combining uniaxial pressure and solution under hydrothermal condition was first demonstrated by Kanahara's group at Kochi University in 1986 and was brought to our attention by the work of Kahari, etc, from University of Oulu on densification of Li2MoO 4 in 2015. This relatively new process showed promising ultra-low densification temperature below 300 °C, however little was known about its fundamental mechanism and scope of applications, which became the main focus of this dissertation. In this work, a uniaxial hydraulic press, a standard stainless steel 1/2 inch diameter die with heating band were utilized in densifying metal oxides. Applied pressure and sintering temperature were between 100 MPa and 700 MPa and from room temperature to 300

  1. Hydrothermal synthesis of highly nitrogen-doped few-layer graphene via solid–gas reaction

    International Nuclear Information System (INIS)

    Liang, Xianqing; Zhong, Jun; Shi, Yalin; Guo, Jin; Huang, Guolong; Hong, Caihao; Zhao, Yidong

    2015-01-01

    Highlights: • A novel approach to synthesis of N-doped few-layer graphene has been developed. • The high doping levels of N in products are achieved. • XPS and XANES results reveal a thermal transformation of N bonding configurations. • The developed method is cost-effective and eco-friendly. - Abstract: Nitrogen-doped (N-doped) graphene sheets with high doping concentration were facilely synthesized through solid–gas reaction of graphene oxide (GO) with ammonia vapor in a self-designed hydrothermal system. The morphology, surface chemistry and electronic structure of N-doped graphene sheets were investigated by TEM, AFM, XRD, XPS, XANES and Raman characterizations. Upon hydrothermal treatment, up to 13.22 at% of nitrogen could be introduced into the crumpled few-layer graphene sheets. Both XPS and XANES analysis reveal that the reaction between oxygen functional groups in GO and ammonia vapor produces amide and amine species in hydrothermally treated GO (HTGO). Subsequent thermal annealing of the resultant HTGO introduces a gradual transformation of nitrogen bonding configurations in graphene sheets from amine N to pyridinic and graphitic N with the increase of annealing temperature. This study provides a simple but cost-effective and eco-friendly method to prepare N-doped graphene materials in large-scale for potential applications

  2. Numerical studies of the flux-to-current ratio method in the KIPT neutron source facility

    International Nuclear Information System (INIS)

    Cao, Y.; Gohar, Y.; Zhong, Z.

    2013-01-01

    The reactivity of a subcritical assembly has to be monitored continuously in order to assure its safe operation. In this paper, the flux-to-current ratio method has been studied as an approach to provide the on-line reactivity measurement of the subcritical system. Monte Carlo numerical simulations have been performed using the KIPT neutron source facility model. It is found that the reactivity obtained from the flux-to-current ratio method is sensitive to the detector position in the subcritical assembly. However, if multiple detectors are located about 12 cm above the graphite reflector and 54 cm radially, the technique is shown to be very accurate in determining the k eff this facility in the range of 0.75 to 0.975. (authors)

  3. National Nanotechnology Laboratory (LNNano) open facilities for scientific community: new methods for polymeric materials characterization

    International Nuclear Information System (INIS)

    Silva, Cristiane A.; Santos, Ramon H.Z. dos; Bernardes, Juliana S.; Gouveia, Rubia F.

    2015-01-01

    National Nanotechnology Laboratory (LNNano) at the National Center for Energy and Materials (CNPEM) presents open facilities for scientific public in some areas. In this work will be discussed the facilities for mainly the polymeric community, as well as new methods for the characterization. Low density polyethylene (LDPE) surfaces were characterized by X-ray microtomography and X-ray photoelectron spectroscopy (XPS). The results obtained by microtomography have shown that these surfaces present different contrasts when compared with the bulk. These differences are correlated with the formation of an oxidized layer at the polymer surface, which consequently have a greater X-ray attenuation. This hypothesis is confirmed by XPS, which shows LDPE surface layers are richer in carbonyl, carboxyl and vinyl groups than the bulk. This work presents that microtomography can be used as a new method for detection and characterization of polymer surface oxidation. (author)

  4. A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles

    OpenAIRE

    Cheng,Kuo-Wei; Hsu,Shan-hui

    2017-01-01

    Kuo-Wei Cheng, Shan-hui Hsu Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, Taipei, Taiwan, Republic of China Abstract: Superparamagnetic iron oxide nanoparticles (SPIO NPs) have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encaps...

  5. A Facile Method for the Preparation of Unsymmetrical Ureas Utilizing Zirconium(IV) Chloride

    International Nuclear Information System (INIS)

    Lee, Anna; Kim, Hee-Kwon; Thompson, David H.

    2016-01-01

    A facile synthetic method for the preparation of unsymmetrical ureas from amines is described.Carbamoyl imidazole compounds were prepared by the reaction of 1,1-carbonyldiimidazole with primary or secondary amines, and further activation by treatment with zirconium(IV) chloride to generate the desired urea. This reaction protocol was applied to the synthesis of tri and tetrasubstituted ureas with high yields. This study provides an alternative guideline for the practical preparation of various unsymmetrical ureas.

  6. Development of likelihood estimation method for criticality accidents of mixed oxide fuel fabrication facilities

    International Nuclear Information System (INIS)

    Tamaki, Hitoshi; Yoshida, Kazuo; Kimoto, Tatsuya; Hamaguchi, Yoshikane

    2010-01-01

    A criticality accident in a MOX fuel fabrication facility may occur depending on several parameters, such as mass inventory and plutonium enrichment. MOX handling units in the facility are designed and operated based on the double contingency principle to prevent criticality accidents. Control failures of at least two parameters are needed for the occurrence of criticality accident. To evaluate the probability of such control failures, the criticality conditions of each parameter for a specific handling unit are necessary for accident scenario analysis to be clarified quantitatively with a criticality analysis computer code. In addition to this issue, a computer-based control system for mass inventory is planned to be installed into MOX handling equipment in a commercial MOX fuel fabrication plant. The reliability analysis is another important issue in evaluating the likelihood of control failure caused by software malfunction. A likelihood estimation method for criticality accident has been developed with these issues been taken into consideration. In this paper, an example of analysis with the proposed method and the applicability of the method are also shown through a trial application to a model MOX fabrication facility. (author)

  7. Hydrothermal-synthesized NiO nanowall array for lithium ion batteries

    International Nuclear Information System (INIS)

    Yan, Xiaoyan; Tong, Xili; Wang, Jian; Gong, Changwei; Zhang, Mingang; Liang, Liping

    2013-01-01

    Graphical abstract: Freestanding NiO nanowall array is prepared via a hydrothermal synthesis method and shows noticeable Li battery performance with good cycle life and high capacity. Highlights: ► NiO nanowall array is prepared by a hydrothermal synthesis method. ► NiO nanowall array with high capacity as anode material for Li ion battery. ► Nanowall array structure is favorable for fast ion/electron transfer. -- Abstract: We report a self-supported NiO nanowall array prepared by a facile hydrothermal synthesis method. The microstructure and morphology of the sample are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The hydrothermal-synthesized NiO nanowalls with thicknesses of ∼20 nm arrange vertically to the substrate forming a net-like nanowall array structure. As anode material for lithium ion batteries, the NiO nanowall array exhibits better electrochemical performances with higher coulombic efficiency and better cycling performance as compared to the dense NiO film. The NiO nanowall array shows an initial coulombic efficiency of 76%, as well as good cycling stability with a capacity of 567 mAh g −1 at 0.3 A g −1 after 50 cycles, higher than those of the dense polycrystalline NiO film (361 mAh g −1 ). The superior electrochemical performance is mainly due to the unique nanowall array structure with shorter diffusion length for mass and charge transport

  8. Hydrothermal Liquefaction of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.

    2010-12-10

    Hydrothermal liquefaction technology is describes in its relationship to fast pyrolysis of biomass. The scope of work at PNNL is discussed and some intial results are presented. HydroThermal Liquefaction (HTL), called high-pressure liquefaction in earlier years, is an alternative process for conversion of biomass into liquid products. Some experts consider it to be pyrolysis in solvent phase. It is typically performed at about 350 C and 200 atm pressure such that the water carrier for biomass slurry is maintained in a liquid phase, i.e. below super-critical conditions. In some applications catalysts and/or reducing gases have been added to the system with the expectation of producing higher yields of higher quality products. Slurry agents ('carriers') evaluated have included water, various hydrocarbon oils and recycled bio-oil. High-pressure pumping of biomass slurry has been a major limitation in the process development. Process research in this field faded away in the 1990s except for the HydroThermal Upgrading (HTU) effort in the Netherlands, but has new resurgence with other renewable fuels in light of the increased oil prices and climate change concerns. Research restarted at Pacific Northwest National Laboratory (PNNL) in 2007 with a project, 'HydroThermal Liquefaction of Agricultural and Biorefinery Residues' with partners Archer-Daniels-Midland Company and ConocoPhillips. Through bench-scale experimentation in a continuous-flow system this project investigated the bio-oil yield and quality that could be achieved from a range of biomass feedstocks and derivatives. The project was completed earlier this year with the issuance of the final report. HydroThermal Liquefaction research continues within the National Advanced Biofuels Consortium with the effort focused at PNNL. The bench-scale reactor is being used for conversion of lignocellulosic biomass including pine forest residue and corn stover. A complementary project is an international

  9. Studies of neutron methods for process control and criticality surveillance of fissile material processing facilities

    International Nuclear Information System (INIS)

    Zoltowski, T.

    1988-01-01

    The development of radiochemical processes for fissile material processing and spent fuel handling need new control procedures enabling an improvement of plant throughput. This is strictly related to the implementation of continuous criticality control policy and developing reliable methods for monitoring the reactivity of radiochemical plant operations in presence of the process perturbations. Neutron methods seem to be applicable for fissile material control in some technological facilities. The measurement of epithermal neutron source multiplication with heuristic evaluation of measured data enables surveillance of anomalous reactivity enhancement leading to unsafe states. 80 refs., 47 figs., 33 tabs. (author)

  10. Reliability Analysis Of Fire System On The Industry Facility By Use Fameca Method

    International Nuclear Information System (INIS)

    Sony T, D.T.; Situmorang, Johnny; Ismu W, Puradwi; Demon H; Mulyanto, Dwijo; Kusmono, Slamet; Santa, Sigit Asmara

    2000-01-01

    FAMECA is one of the analysis method to determine system reliability on the industry facility. Analysis is done by some procedure that is identification of component function, determination of failure mode, severity level and effect of their failure. Reliability value is determined by three combinations that is severity level, component failure value and critical component. Reliability of analysis has been done for fire system on the industry by FAMECA method. Critical component which identified is pump, air release valve, check valve, manual test valve, isolation valve, control system etc

  11. Facile Synthesis of Long, Straight and Uniform Copper Nanowires via a Solvothermal Method

    Institute of Scientific and Technical Information of China (English)

    Chunfu Lin; Hong Lin; Ning Wang; Xing Zhang; Jun Yang; Jianbo Li; Xiaozhan Yang

    2006-01-01

    Copper nanowires were facilely prepared via a solvothermal method. In this method, cetyltrimethylammonium bromide (CTAB) was used as a soft template, copper nitrate was an inorganic precursor, and absolute ethanol served as a reducing agent as well as a solvent. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the as-prepared copper nanowires. The as-prepared copper nanowires are fairly uniform and long. The majority of them are longer than 100 μm and some even longer than 200 μm. Furthermore, most nanowires are quite straight. In addition,The mechanism of the growth process of copper nanowires was discussed.

  12. The arrangement of the seismic design method of the underground facility

    International Nuclear Information System (INIS)

    Tanai, Kenji; Horita, Masakuni; Dewa, Katsuyuki; Gouke, Mitsuo

    2002-03-01

    Earthquake resistance for the underground structure is higher than the ground structure. Therefore, the case of examining the earthquake resistance of underground structure was little. However, it carries out the research on the aseismic designing method of underground structure, since the tunnel was struck by Hyogo-ken Nanbu Earthquake, and it has obtained a much knowledge. However, an object of the most study was behavior at earthquake of the comparatively shallow underground structure in the alluvial plain board, and it not carry out the examination on behavior at earthquake of underground structure in the deep rock mass. In the meantime, underground disposal facility of the high level radioactive waste constructs in the deep underground, and it carries out the operation in these tunnels. In addition, it has made almost the general process of including from the construction start to the backfilling to be about 60 years (Japan Nuclear Fuel Cycle Development Institute, 1999). During these periods, it is necessary to also consider the earthquake resistance as underground structure from the viewpoint of the safety of facilities. Then, it extracted future problem as one of the improvement of the basis information for the decision of the safety standard and guideline of the country on earthquake-resistant design of the underground disposal facility, while it carried out investigation and arrangement of earthquake-resistant design cases, guidelines and analysis method on existing underground structure, etc. And, the research items for the earthquake resistance assessment of underground structure as case study of the underground research laboratory. (author)

  13. Use of risk assessment methods for security design and analysis of nuclear and radioactive facilities

    International Nuclear Information System (INIS)

    Vasconcelos, Vanderley de; Andrade, Marcos C.; Jordao, Elizabete

    2011-01-01

    The objective of this work is to evaluate the applicability of risk assessment methods for analyzing the physical protection of nuclear and radioactive facilities. One of the important processes for physical protection in nuclear and radioactive facilities is the identifying of areas containing nuclear materials, structures, systems or components to be protected from sabotage, which could directly or indirectly lead to unacceptable radiological consequences. A survey of the international guidelines and recommendations about vital area identification, design basis threat (DBT), and the security of nuclear and radioactive facilities was carried out. The traditional methods used for quantitative risk assessment, like FMEA (Failure Mode and Effect Analysis), Event and Decision Trees, Fault and Success Trees, Vulnerability Assessment, Monte Carlo Simulation, Probabilistic Safety Assessment, Scenario Analysis, and Game Theory, among others, are highlighted. The applicability of such techniques to security issues, their pros and cons, the general resources needed to implement them, as data or support software, are analyzed. Finally, an approach to security design and analysis, beginning with a qualitative and preliminary examination to determine the range of possible scenarios, outcomes, and the systems to be included in the analyses, and proceeding to a progressively use of more quantitative techniques is presented. (author)

  14. Synthesis of BiFeO{sub 3} thin films on single-terminated Nb : SrTiO{sub 3} (111) substrates by intermittent microwave assisted hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Velasco-Davalos, Ivan; Ambriz-Vargas, Fabian; Kolhatkar, Gitanjali; Thomas, Reji, E-mail: ruediger@emt.inrs.ca, E-mail: reji.thomas@emt.inrs.ca; Ruediger, Andreas, E-mail: ruediger@emt.inrs.ca, E-mail: reji.thomas@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650 Lionel-Boulet, Varennes, Québec, J3X1S2 (Canada)

    2016-06-15

    We report on a simple and fast procedure to create arrays of atomically flat terraces on single crystal SrTiO{sub 3} (111) substrates and the deposition of ferroelectric BiFeO{sub 3} thin films on such single-terminated surfaces. A microwave-assisted hydrothermal method in deionized water and ammonia solution selectively removes either (SrO{sub 3}){sup 4−} or Ti{sup 4+} layers to ensure the same chemical termination on all terraces. Measured step heights of 0.225 nm (d{sub 111}) and uniform contrast in the phase image of the terraces confirm the single termination in pure and Nb doped SrTiO{sub 3} single crystal substrates. Multiferroic BiFeO{sub 3} thin films were then deposited by the same microwave assisted hydrothermal process on Nb : SrTiO{sub 3} (111) substrates. Bi(NO{sub 3}){sub 3} and Fe(NO{sub 3}){sub 3} along with KOH served as the precursors solution. Ferroelectric behavior of the BiFeO{sub 3} films on Nb : SrTiO{sub 3} (100) substrates was verified by piezoresponse force microscopy.

  15. Calibration and intercomparison methods of dose calibrators used in nuclear medicine facilities

    International Nuclear Information System (INIS)

    Costa, Alessandro Martins da

    1999-01-01

    Dose calibrators are used in most of the nuclear medicine facilities to determine the amount of radioactivity administered to a patient in a particular investigation or therapeutic procedure. It is therefore of vital importance that the equipment used presents good performance and is regular;y calibrated at a authorized laboratory. This occurs of adequate quality assurance procedures are carried out. Such quality control tests should be performed daily, other biannually or yearly, testing, for example, its accuracy and precision, the reproducibility and response linearity. In this work a commercial dose calibrator was calibrated with solution of radionuclides used in nuclear medicine. Simple instrument tests, such as response linearity and the response variation of the source volume increase at a constant source activity concentration, were performed. This instrument can now be used as a working standard for calibration of other dose calibrators/ An intercomparison procedure was proposed as a method of quality control of dose calibrators used in nuclear medicine facilities. (author)

  16. Design of environmental monitoring system of nuclear facility based on a method of pattern recognition

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, N; Kiyose, R; Yamamoto, Y [Tokyo Univ. (Japan). Faculty of Engineering

    1977-10-01

    The problem to optimize the number and locations of environmental radiation monitoring detectors is formulated by taking the specifically defined distance measures as a performance index and solved numerically using heuristic programming such as branch and bound method. An ideal numerical example neglecting noises due to background radiation, shows that the desirable number and locations of detectors are determined mainly by the atmospheric conditions and are not significantly influenced by the variation of the rate and pattern of activity release from the nuclear facility. It is shown also that the appropriate and sufficient number of monitoring detectors to be located around the facility will be from three to six at most, if considered from the viewpoint of pattern recognition.

  17. Decoration of ZnO Nanorods with Coral Reefs like NiO Nanostructures by the Hydrothermal Growth Method and Their Luminescence Study

    Directory of Open Access Journals (Sweden)

    Mazhar Ali Abbasi

    2014-01-01

    Full Text Available Composite nanostructures of coral reefs like p-type NiO/n-type ZnO were synthesized on fluorine-doped tin oxide glass substrates by hydrothermal growth. Structural characterization was performed by field emission scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction techniques. This investigation shows that the adopted synthesis leads to high crystalline quality nanostructures. The morphological study shows that the coral reefs like nanostructures are densely packed on the ZnO nanorods. Cathodoluminescence (CL spectra for the synthesized composite nanostructures are dominated mainly by a broad interstitial defect related luminescence centered at ~630 nm. Spatially resolved CL images reveal that the luminescence of the decorated ZnO nanostructures is enhanced by the presence of the NiO.

  18. Synthesis and characterization of high-quality water-soluble CdMnTe quantum dots capped by N-acetyl-L-cysteine through hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Fang; Li, Jiaotian; Wang, Fengxue; Yang, Tanming; Zhao, Dan, E-mail: wqzhdpai@163.com

    2015-03-15

    High-quality water-soluble Mn{sup 2+} doped CdTe quantum dots (QDs) with N-acetyl-L-cysteine (NAC) as capping reagent have been synthesized through hydrothermal route, allowing a rapid preparation time (<1 h), tunable emitting peaks (from 530 to 646 nm) and excellent quantum yields (approximately 50%). The influences of various experimental variables, including Mn-to-Cd ratio, Te-to-Cd ratio, pH value, and reaction time on the growth rate and luminescent properties of the obtained QDs have been systematically investigated. And the optimum reaction conditions (Cd:Mn:NAC:Te=1.0:1.0:2.4:0.2, pH=9.5, 35 min, 200 °C) are found out. The optical features and structure of the obtained CdMnTe QDs have been characterized through fluorescence spectroscopy, UV absorption spectroscopy and TEM. In particular, we realized qualitative, semi-quantitative and quantitative studies on the doping of Mn to CdTe QDs through XPS, EDS, and AAS. The actual molar ratio of Mn to Cd in CdMnTe QDs (551 nm) is 1.166:1.00, very close to the feed ratios (1:1). - Highlights: • Mn doped CdTe QDs have been synthesized through one-pot hydrothermal route. • The prepared QDs possess excellent quantum yields as high as 63.1% and tunable emitting peaks from 530 to 646 nm. • We found out that the enhancement of Mn:Cd will decrease the QY of the prepared QDs and lead to the blueshift of emission peaks. • The QDs have been characterized through TEM, EDS, XPS, and AAS.

  19. Direct formation of new, phase-stable, and photoactive anatase-type Ti1-2XNbXScXO2 solid solution nanoparticles by hydrothermal method

    International Nuclear Information System (INIS)

    Hirano, Masanori; Ito, Takaharu

    2008-01-01

    A new anatase phase of photoactive Ti 1-2X Nb X Sc X O 2 (X = 0-0.2) solid solutions was directly formed as nanoparticles from precursor solutions of TiOSO 4 , NbCl 5 , and Sc(NO 3 ) 3 under mild hydrothermal conditions at 180 deg. C for 5 h using the hydrolysis of urea. With the increase of the content of niobium and scandium from X = 0 to 0.2, the lattice parameters a 0 and c 0 , the crystallite size, and the optical band gap of anatase gradually increased. Their photocatalytic activity and adsorptivity were evaluated separately by the measurement of the concentration of methylene blue (MB) remained in the solution in the dark or under UV-light irradiation. The anatase-type Ti 1-2X Nb X Sc X O 2 (X = 0.05) showed approximately two times and three times as high photocatalytic activity as those of the hydrothermal anatase-type pure TiO 2 and commercially available reference pure TiO 2 (ST-01), respectively. The anatase phase of Ti 1-2X Nb X Sc X O 2 (X = 0-0.2) existed stably up to 900 deg. C during heat treatment in air. New rutile-type Ti 1-2X Nb X Sc X O 2 solid solutions are formed through the phase transformation. The starting temperature of anatase-to-rutile phase transformation for Ti 1-2X Nb X Sc X O 2 (X = 0-0.2) solid solutions was delayed but its completing temperature was accelerated

  20. Hydrothermally grown zeolite crystals

    International Nuclear Information System (INIS)

    Durrani, S.K.; Qureshi, A.H.; Hussain, M.A.; Qazi, N.K.

    2009-01-01

    The aluminium-deficient and ferrosilicate zeolite-type materials were synthesized by hydrothermal process at 150-170 degree C for various periods of time from the mixtures containing colloidal reactive silica, sodium aluminate, sodium hydroxide, iron nitrate and organic templates. Organic polycation templates were used as zeolite crystal shape modifiers to enhance relative growth rates. The template was almost completely removed from the zeolite specimens by calcination at 550 degree C for 8h in air. Simultaneous thermogravimetric (TG) and differential thermal analysis (DTA) was performed to study the removal of water molecules and the amount of organic template cations occluded inside the crystal pore of zeolite framework. The 12-13% weight loss in the range of (140-560 degree C) was associated with removal of the (C/sub 3/H/sub 7/)/sub 4/ N+ cation and water molecules. X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) techniques were employed to study the structure, morphology and surface features of hydrothermally grown aluminium-deficient and ferrosilicate zeolite-type crystals. In order to elucidate the mode of zeolite crystallization the crystallinity and unit cell parameters of the materials were determined by XRD, which are the function of Al and Fe contents of zeolites. (author)

  1. Hydrothermal effects on montmorillonite

    International Nuclear Information System (INIS)

    Pusch, R.; Karnland, O.

    1988-06-01

    Hydrothermal effects on montmorillonite clay are usually taken to have the form of conversion of this clay mineral to other species, such as illite, disregarding microstructural alteration and cementation caused by precipitation of silica and other compounds. The report is focussed on identification of the primary processes that are involved in such alteration, the release of silica and the microstructural changes associated with heating being of major interest. In the first test phase, Na montmorillonite in distilled water was investigated by XRD, rheology tests and electron microscopy after heating to 60-225 0 C for 0.01 to 1 year. The preliminary conclusions are that heating produces contraction of the particle network to form dense 'branches', the effect being most obvious at the highest temperature but of significance even at 60-100 0 C. Release of substantial amounts of silica gas been documented for temperatures exceeding 150 0 and precipitation of silica was observed on cooling after the hydrothermal testing under the closed conditions that prevailed throughout the tests. The precipitates, which appeared to be amorphous and probably consisted of hydrous silica gels, were concluded to have increased the mechanical strength and caused some brittleness, particularly of the dense clays. The nature of the silica release, which is assumed to be associated with beidellitization, may be closely related to an unstable state of a certain fraction of tetrahedral silica at heat-inducted transfer between two different crystal modes of montmorillonite. (orig.)

  2. Testing of the Defense Waste Processing Facility Cold Chemical Dissolution Method in Sludge Batch 9 Qualification

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Pareizs, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coleman, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Young, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brown, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-10

    For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) tests the applicability of the digestion methods used by the DWPF Laboratory for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) Receipt samples and SRAT Product process control samples. DWPF SRAT samples are typically dissolved using a method referred to as the DWPF Cold Chemical or Cold Chem Method (CC), (see DWPF Procedure SW4- 15.201). Testing indicates that the CC method produced mixed results. The CC method did not result in complete dissolution of either the SRAT Receipt or SRAT Product with some fine, dark solids remaining. However, elemental analyses did not reveal extreme biases for the major elements in the sludge when compared with analyses obtained following dissolution by hot aqua regia (AR) or sodium peroxide fusion (PF) methods. The CC elemental analyses agreed with the AR and PF methods well enough that it should be adequate for routine process control analyses in the DWPF after much more extensive side-by-side tests of the CC method and the PF method are performed on the first 10 SRAT cycles of the Sludge Batch 9 (SB9) campaign. The DWPF Laboratory should continue with their plans for further tests of the CC method during these 10 SRAT cycles.

  3. VISA: a method for evaluating the performance of integrated safeguards systems at nuclear facilities

    International Nuclear Information System (INIS)

    Donnelly, H.; Fullwood, R.; Glancy, J.

    1977-06-01

    This is the second volume of a two volume report on the VISA method for evaluating safeguards at fixed-site facilities. This volume contains appendices that support the description of the VISA concept and the initial working version of the method, VISA-1, presented in Volume I. The information is separated into four appendices, each describing details of one of the four analysis modules that comprise the analysis sections of the method. The first appendix discusses Path Analysis methodology, applies it to a Model Fuel Facility, and describes the computer codes that are being used. Introductory material on Path Analysis given in Chapter 3.2.1 and Chapter 4.2.1 of Volume I. The second appendix deals with Detection Analysis, specifically the schemes used in VISA-1 for classifying adversaries and the methods proposed for evaluating individual detection mechanisms in order to build the data base required for detection analysis. Examples of evaluations on identity-access systems, SNM portal monitors, and intrusion devices are provided. The third appendix describes the Containment Analysis overt-segment path ranking, the Monte Carlo engagement model, the network simulation code, the delay mechanism data base, and the results of a sensitivity analysis. The last appendix presents general equations used in Interruption Analysis for combining covert-overt segments and compares them with equations given in Volume I, Chapter 3

  4. Reliability Verification of DBE Environment Simulation Test Facility by using Statistics Method

    International Nuclear Information System (INIS)

    Jang, Kyung Nam; Kim, Jong Soeg; Jeong, Sun Chul; Kyung Heum

    2011-01-01

    In the nuclear power plant, all the safety-related equipment including cables under the harsh environment should perform the equipment qualification (EQ) according to the IEEE std 323. There are three types of qualification methods including type testing, operating experience and analysis. In order to environmentally qualify the safety-related equipment using type testing method, not analysis or operation experience method, the representative sample of equipment, including interfaces, should be subjected to a series of tests. Among these tests, Design Basis Events (DBE) environment simulating test is the most important test. DBE simulation test is performed in DBE simulation test chamber according to the postulated DBE conditions including specified high-energy line break (HELB), loss of coolant accident (LOCA), main steam line break (MSLB) and etc, after thermal and radiation aging. Because most DBE conditions have 100% humidity condition, in order to trace temperature and pressure of DBE condition, high temperature steam should be used. During DBE simulation test, if high temperature steam under high pressure inject to the DBE test chamber, the temperature and pressure in test chamber rapidly increase over the target temperature. Therefore, the temperature and pressure in test chamber continue fluctuating during the DBE simulation test to meet target temperature and pressure. We should ensure fairness and accuracy of test result by confirming the performance of DBE environment simulation test facility. In this paper, in order to verify reliability of DBE environment simulation test facility, statistics method is used

  5. Enhanced electrochemical performance of different morphological C/LiMnPO4 nanoparticles from hollow-sphere Li3PO4 precursor via a delicate polyol-assisted hydrothermal method

    Science.gov (United States)

    Cui, Yu-Ting; Xu, Ning; Kou, Li-Qin; Wu, Meng-Tao; Chen, Li

    2014-03-01

    With the hollow-sphere Li3PO4 as precursor, a delicate polyol-assisted hydrothermal method is devised to synthesize high-performance LiMnPO4. Orthorhombic shaped, irregular flaky shaped and sphere-like LiMnPO4 are sequentially prepared by decreasing the water-diethylene glycol (DEG) ratio. The capacity, cycling stability and rate performance of all samples prepared by the new synthesis method are improved significantly. And the C/LiMnPO4 with irregular flaky shape exhibits a capacity of 154.1 mA h g-1 at C/20, 147.4 mA h g-1 at C/10 and 102.5 mA h g-1 at 2 C, which is the best performance ever reported for LiMnPO4 active material with similar carbon additives.

  6. Structural, optical and magnetic studies of CuFe2O4, MgFe2O4 and ZnFe2O4 nanoparticles prepared by hydrothermal/solvothermal method

    Science.gov (United States)

    Kurian, Jessyamma; Mathew, M. Jacob

    2018-04-01

    In this paper we report the structural, optical and magnetic studies of three spinel ferrites namely CuFe2O4, MgFe2O4 and ZnFe2O4 prepared in an autoclave under the same physical conditions but with two different liquid medium and different surfactant. We use water as the medium and trisodium citrate as the surfactant for one method (Hydrothermal method) and ethylene glycol as the medium and poly ethylene glycol as the surfactant for the second method (solvothermal method). The phase identification and structural characterization are done using XRD and morphological studies are carried out by TEM. Cubical and porous spherical morphologies are obtained for hydrothermal and solvothermal process respectively without any impurity phase. The optical studies are carried out using FTIR and UV-Vis reflectance spectra. In order to elucidate the nonlinear optical behaviour of the prepared nanomaterial, open aperture z-scan technique is used. From the fitted z-scan curves nonlinear absorption coefficient and the saturation intensity are determined. The magnetic characterization of the samples is performed at room temperature using vibrating sample magnetometer measurements. The M-H curves obtained are fitted using theoretical equation and the different components of magnetization are determined. Nanoparticles with high saturation magnetization are obtained for MgFe2O4 and ZnFe2O4 prepared under solvothermal reaction. The magnetic hyperfine parameters and the cation distribution of the prepared materials are determined using room temperature Mössbauer spectroscopy. The fitted spectra reveal the difference in the magnetic hyperfine parameters owing to the change in size and morphology.

  7. Classification of Reactor Facility Operational State Using SPRT Methods with Radiation Sensor Networks

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez Aviles, Camila A. [ORNL; Rao, Nageswara S. [ORNL

    2018-01-01

    We consider the problem of inferring the operational state of a reactor facility by using measurements from a radiation sensor network, which is deployed around the facility’s ventilation stack. The radiation emissions from the stack decay with distance, and the corresponding measurements are inherently random with parameters determined by radiation intensity levels at the sensor locations. We fuse measurements from network sensors to estimate the intensity at the stack, and use this estimate in a one-sided Sequential Probability Ratio Test (SPRT) to infer the on/off state of the reactor facility. We demonstrate the superior performance of this method over conventional majority vote fusers and individual sensors using (i) test measurements from a network of NaI sensors, and (ii) emulated measurements using radioactive effluents collected at a reactor facility stack. We analytically quantify the performance improvements of individual sensors and their networks with adaptive thresholds over those with fixed ones, by using the packing number of the radiation intensity space.

  8. Development of a vacuum leak test method for large-scale superconducting magnet test facilities

    International Nuclear Information System (INIS)

    Kawano, Katsumi; Hamada, Kazuya; Okuno, Kiyoshi; Kato, Takashi

    2006-01-01

    Japan Atomic Energy Agency (JAEA) has developed leak detection technology for liquid helium temperature experiments in large-scale superconducting magnet test facilities. In JAEA, a cryosorption pump that uses an absorbent cooled by liquid nitrogen with a conventional helium leak detector, is used to detect helium gas that is leaking from pressurized welded joints of pipes and valves in a vacuum chamber. The cryosorption pump plays the role of decreasing aerial components, such as water, nitrogen and oxygen, to increase the sensitivity of helium leak detection. The established detection sensitivity for helium leak testing is 10 -10 to 10 -9 Pam 3 /s. A total of 850 welded and mechanical joints inside the cryogenic test facility for the ITER Central Solenoid Model Coil (CSMC) experiments have been tested. In the test facility, 73 units of glass fiber-reinforced plastic (GFRP) insulation break are used. The amount of helium permeation through the GFRP was recorded during helium leak testing. To distinguish helium leaks from insulation-break permeation, the helium permeation characteristic of the GFRP part was measured as a function of the time of helium charging. Helium permeation was absorbed at 6 h after helium charging, and the detected permeation is around 10 -7 Pam 3 /s. Using the helium leak test method developed, CSMC experiments have been successfully completed. (author)

  9. The unit cost factors and calculation methods for decommissioning - Cost estimation of nuclear research facilities

    International Nuclear Information System (INIS)

    Kwan-Seong Jeong; Dong-Gyu Lee; Chong-Hun Jung; Kune-Woo Lee

    2007-01-01

    Available in abstract form only. Full text of publication follows: The uncertainties of decommissioning costs increase high due to several conditions. Decommissioning cost estimation depends on the complexity of nuclear installations, its site-specific physical and radiological inventories. Therefore, the decommissioning costs of nuclear research facilities must be estimated in accordance with the detailed sub-tasks and resources by the tasks of decommissioning activities. By selecting the classified activities and resources, costs are calculated by the items and then the total costs of all decommissioning activities are reshuffled to match with its usage and objectives. And the decommissioning cost of nuclear research facilities is calculated by applying a unit cost factor method on which classification of decommissioning works fitted with the features and specifications of decommissioning objects and establishment of composition factors are based. Decommissioning costs of nuclear research facilities are composed of labor cost, equipment and materials cost. Of these three categorical costs, the calculation of labor costs are very important because decommissioning activities mainly depend on labor force. Labor costs in decommissioning activities are calculated on the basis of working time consumed in decommissioning objects and works. The working times are figured out of unit cost factors and work difficulty factors. Finally, labor costs are figured out by using these factors as parameters of calculation. The accuracy of decommissioning cost estimation results is much higher compared to the real decommissioning works. (authors)

  10. Additional Energy Losses from Asymmetric and Non-Sinusoidal Current in an Electrical Facility and Methods of their Reduction

    OpenAIRE

    Tarasov, Evgeny Vladimirovich; Bulyga, Leonid Leonidovich; Ushakov, Vasily Yakovlevich; Kharlov, Nikolay Nikolaevich

    2015-01-01

    Influence of the asymmetry and higher harmonics of current on the operation of an electrical facility is analyzed. The level of additional losses from the asymmetric and non-sinusoidal currents is evaluated for a 110 kV electrical network in the Siberian Region of the Russian Federation. Methods for reducing the additional energy losses in the electrical facility are suggested.

  11. Nanogeochemistry of hydrothermal magnetite

    Science.gov (United States)

    Deditius, Artur P.; Reich, Martin; Simon, Adam C.; Suvorova, Alexandra; Knipping, Jaayke; Roberts, Malcolm P.; Rubanov, Sergey; Dodd, Aaron; Saunders, Martin

    2018-06-01

    Magnetite from hydrothermal ore deposits can contain up to tens of thousands of parts per million (ppm) of elements such as Ti, Si, V, Al, Ca, Mg, Na, which tend to either structurally incorporate into growth and sector zones or form mineral micro- to nano-sized particles. Here, we report micro- to nano-structural and chemical data of hydrothermal magnetite from the Los Colorados iron oxide-apatite deposit in Chile, where magnetite displays both types of trace element incorporation. Three generations of magnetites (X-Z) were identified with concentrations of minor and trace elements that vary significantly: SiO2, from below detection limit (bdl) to 3.1 wt%; Al2O3, 0.3-2.3 wt%; CaO, bdl-0.9 wt%; MgO, 0.02-2.5 wt%; TiO2, 0.1-0.4 wt%; MnO, 0.04-0.2 wt%; Na2O, bdl-0.4 wt%; and K2O, bdl-0.4 wt%. An exception is V2O3, which is remarkably constant, ranging from 0.3 to 0.4 wt%. Six types of crystalline nanoparticles (NPs) were identified by means of transmission electron microscopy in the trace element-rich zones, which are each a few micrometres wide: (1) diopside, (2) clinoenstatite; (3) amphibole, (4) mica, (5) ulvöspinel, and (6) Ti-rich magnetite. In addition, Al-rich nanodomains, which contain 2-3 wt% of Al, occur within a single crystal of magnetite. The accumulation of NPs in the trace element-rich zones suggest that they form owing to supersaturation from a hydrothermal fluid, followed by entrapment during continuous growth of the magnetite surface. It is also concluded that mineral NPs promote exsolution of new phases from the mineral host, otherwise preserved as structurally bound trace elements. The presence of abundant mineral NPs in magnetite points to a complex incorporation of trace elements during growth, and provides a cautionary note on the interpretation of micron-scale chemical data of magnetite.

  12. Vapor-phase hydrothermal transformation of HTiOF3 intermediates into {001} faceted anatase single-crystalline nanosheets.

    Science.gov (United States)

    Liu, Porun; Wang, Yun; Zhang, Haimin; An, Taicheng; Yang, Huagui; Tang, Zhiyong; Cai, Weiping; Zhao, Huijun

    2012-12-07

    For the first time, a facile, one-pot hydrofluoric acid vapor-phase hydrothermal (HF-VPH) method is demonstrated to directly grow single-crystalline anatase TiO(2) nanosheets with 98.2% of exposed {001} faceted surfaces on the Ti substrate via a distinctive two-stage formation mechanism. The first stage produces a new intermediate crystal (orthorhombic HTiOF(3) ) that is transformed into anatase TiO(2) nanosheets during the second stage. The findings reveal that the HF-VPH reaction environment is unique and differs remarkably from that of liquid-phase hydrothermal processes. The uniqueness of the HF-VPH conditions can be readily used to effectively control the nanostructure growth. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Improvement of numerical simulation methods on safety assessment of the spent fuel storage facility

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    Improvement of numerical simulation methods on safety assessment of the spent fuel storage facility is one of main objectives of JNES activities. For the thermal and structural analyses, the radiative heat transfer analysis code S-FOKS has been developed to reduce computing time and to avoid using large memory area. In order to simulate the specular reflection, a new model (called 'model-2') is planned to install to S-FOKS code. The theoretical values with the specular reflection in simple geometry were lead to verify S-FOKS model-2. (author)

  14. Mathematical programming models for solving in equal-sized facilities layout problems. A genetic search method

    International Nuclear Information System (INIS)

    Tavakkoli-Moghaddam, R.

    1999-01-01

    This paper present unequal-sized facilities layout solutions generated by a genetic search program. named Layout Design using a Genetic Algorithm) 9. The generalized quadratic assignment problem requiring pre-determined distance and material flow matrices as the input data and the continuous plane model employing a dynamic distance measure and a material flow matrix are discussed. Computational results on test problems are reported as compared with layout solutions generated by the branch - and bound algorithm a hybrid method merging simulated annealing and local search techniques, and an optimization process of an enveloped block

  15. Examination of methods of proliferation control for application to nuclear fuel reprocessing facilities

    International Nuclear Information System (INIS)

    O'Hara, F.A.

    1980-01-01

    Potential methods are examined that could be applied to the nuclear fuel reprocessing facility as a means of more effectively controlling the proliferation threat and, at the same time, permitting the further development of nuclear power as an energy source. The proposed remedies for this problem are basically technical or economic and political in nature and include: ''technical fixes'', institutional arrangements, and international political solutions. Each of these approaches to the problem is examined, along with a consideration of their interaction and an estimation of their effectiveness, either individually or in combination. 22 refs

  16. A method for assessing the structural shielding in diagnostic x-ray facilities

    International Nuclear Information System (INIS)

    Almeida, F.; Martinez de la Fuente, O.; Perez, C.

    1992-01-01

    The design of each X-Ray medical facility involves, in order to guarantee the optimun levels of Radiologic safety for everybody who could be exposed during the performance of the examinations the need of assessing the required shieldings for the room which contains the emiter tubes. In such sense, this paper gives a number of criteria to calculate the structural requirements for the diverse configurations which exist in Health Centres using the method proposed by NCRP in its Report 49 as a reference. (author)

  17. An improved method for lifting and transporting anesthetized pigs within an animal facility

    DEFF Research Database (Denmark)

    Schumacher-Petersen, Camilla; Hammelev, Karsten Pharao; Flescher, Jens Erik

    2014-01-01

    Transporting anesthetized pigs in a laboratory setting often requires strenuous manual lifting, posing a hazard to the safety of animal care personnel and to the welfare of the pigs. The authors developed an improved approach to lifting and transporting anesthetized pigs weighing up to 350 kg using...... mechanical lifts. Different equipment was used to accommodate pigs of different sizes as well as the building designs of three animal facilities. Using the lifts, anesthetized pigs are carried on sheets to maintain their comfort while being transported. The approach refines previous methods for handling...

  18. A systematic method for identifying vital areas at complex nuclear facilities.

    Energy Technology Data Exchange (ETDEWEB)

    Beck, David Franklin; Hockert, John

    2005-05-01

    Identifying the areas to be protected is an important part of the development of measures for physical protection against sabotage at complex nuclear facilities. In June 1999, the International Atomic Energy Agency published INFCIRC/225/Rev.4, 'The Physical Protection of Nuclear Material and Nuclear Facilities.' This guidance recommends that 'Safety specialists, in close cooperation with physical protection specialists, should evaluate the consequences of malevolent acts, considered in the context of the State's design basis threat, to identify nuclear material, or the minimum complement of equipment, systems or devices to be protected against sabotage.' This report presents a structured, transparent approach for identifying the areas that contain this minimum complement of equipment, systems, and devices to be protected against sabotage that is applicable to complex nuclear facilities. The method builds upon safety analyses to develop sabotage fault trees that reflect sabotage scenarios that could cause unacceptable radiological consequences. The sabotage actions represented in the fault trees are linked to the areas from which they can be accomplished. The fault tree is then transformed (by negation) into its dual, the protection location tree, which reflects the sabotage actions that must be prevented in order to prevent unacceptable radiological consequences. The minimum path sets of this fault tree dual yield, through the area linkage, sets of areas, each of which contains nuclear material, or a minimum complement of equipment, systems or devices that, if protected, will prevent sabotage. This method also provides guidance for the selection of the minimum path set that permits optimization of the trade-offs among physical protection effectiveness, safety impact, cost and operational impact.

  19. Engineering for a disposal facility using the in-room emplacement method

    Energy Technology Data Exchange (ETDEWEB)

    Baumgartner, P; Bilinsky, D M; Ates, Y; Read, R S; Crosthwaite, J L; Dixon, D A

    1996-06-01

    This report describes three nuclear fuel waste disposal vaults using the in-room emplacement method. First, a generic disposal vault design is provided which is suitable for a depth range of 500 m to 1000 m in highly stressed, sparsely fractured rock. The design process is described for all components of the system. The generic design is then applied to two different disposal vaults, one at a depth of 750 m in a low hydraulically conductive, sparsely fractured rock mass and another at a depth of 500 m in a higher conductivity, moderately fractured rock mass. In the in-room emplacement method, the disposal containers with used-fuel bundles are emplaced within the confines of the excavated rooms of a disposal vault. The discussion of the disposal-facility design process begins with a detailed description of a copper-shell, packed-particulate disposal container and the factors that influenced its design. The disposal-room generic design is presented including the detailed specifications, the scoping and numerical thermal and thermal mechanical analyses, the backfilling and sealing materials, and the operational processes. One room design is provided that meets all the requirements for a vault depth range of 500 to 1000 m. A disposal-vault layout and the factors that influenced its design are also presented, including materials handling, general logistics, and separation of radiological and nonradiological operations. Modifications to the used-fuel packaging plant for the filling and sealing of the copper-shell, packed-particulate disposal containers and a brief description of the common surface facilities needed by the disposal vault and the packaging plant are provided. The implementation of the disposal facility is outlined, describing the project stages and activities and itemizing a specific plan for each of the project stages: siting, construction, operation; decommissioning; and closure. (author). 72 refs., 15 tabs., 63 figs.

  20. Engineering for a disposal facility using the in-room emplacement method

    International Nuclear Information System (INIS)

    Baumgartner, P.; Bilinsky, D.M.; Ates, Y.; Read, R.S.; Crosthwaite, J.L.; Dixon, D.A.

    1996-06-01

    This report describes three nuclear fuel waste disposal vaults using the in-room emplacement method. First, a generic disposal vault design is provided which is suitable for a depth range of 500 m to 1000 m in highly stressed, sparsely fractured rock. The design process is described for all components of the system. The generic design is then applied to two different disposal vaults, one at a depth of 750 m in a low hydraulically conductive, sparsely fractured rock mass and another at a depth of 500 m in a higher conductivity, moderately fractured rock mass. In the in-room emplacement method, the disposal containers with used-fuel bundles are emplaced within the confines of the excavated rooms of a disposal vault. The discussion of the disposal-facility design process begins with a detailed description of a copper-shell, packed-particulate disposal container and the factors that influenced its design. The disposal-room generic design is presented including the detailed specifications, the scoping and numerical thermal and thermal mechanical analyses, the backfilling and sealing materials, and the operational processes. One room design is provided that meets all the requirements for a vault depth range of 500 to 1000 m. A disposal-vault layout and the factors that influenced its design are also presented, including materials handling, general logistics, and separation of radiological and nonradiological operations. Modifications to the used-fuel packaging plant for the filling and sealing of the copper-shell, packed-particulate disposal containers and a brief description of the common surface facilities needed by the disposal vault and the packaging plant are provided. The implementation of the disposal facility is outlined, describing the project stages and activities and itemizing a specific plan for each of the project stages: siting, construction, operation; decommissioning; and closure. (author)

  1. Controlled synthesis of various ZnO nanostructured materials by capping agents-assisted hydrothermal method for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Akhtar, M. Shaheer; Khan, M. Alam; Yang, O-Bong [School of Semiconductor and Chemical Engineering, Center for Advanced Radiation Technology, Jeon-Ju (Korea); New and Renewable Energy Center, Chonbuk National University, Jeon-Ju (Korea); Jeon, Myung Seok [Photocatalysis and Photoelectrochemistry Research Center, Korea Institute of Energy Research (KIER), Daejon 305-343 (Korea)

    2008-11-15

    In this work, the morphology of ZnO materials could be controlled by changing the capping agent at constant alkali solution in hydrothermal process. ZnO nanomaterials with the structure of flowers, sheet-spheres and plates were obtained with the capping agent of ammonia, citric acid and oxalic acid, respectively. Thus prepared ZnO nanomaterials were characterized and applied as the photo-anode materials for dye-sensitized solar cell. All synthesized ZnO nanomaterials possessed high crystalline wurtzite structures grown in the (001) direction with the size of 2-4{mu}m, which consist of ZnO units around 20-400 nm. Among them, Sheet-sphere ZnO showed the highest crystallinity, surface area and uniform film morphology, resulting in the significantly improved PV performance with the overall conversion efficiency of 2.61% in dye-sensitized solar cell (DSSC) fabricated with sheet-sphere ZnO. It is notable that the ZnO materials with sphere structure may be the optimal photo-anode material among various ZnO nanomaterials for DSSC. (author)

  2. Nitrogen Dioxide-Sensing Properties at Room Temperature of Metal Oxide-Modified Graphene Composite via One-Step Hydrothermal Method

    Science.gov (United States)

    Zhang, Dongzhi; Liu, Jingjing; Xia, Bokai

    2016-08-01

    A metal oxide/graphene composite film-based sensor toward room-temperature detection of ppm-level nitrogen dioxide (NO2) gas has been demonstrated. The sensor prototype was constructed on a PCB substrate with microelectrodes, and a tin oxide-reduced graphene oxide (SnO2-rGO) composite as sensing film was prepared by one-step hydrothermal synthesis of tin tetrachloride pentahydrate solution in the presence of graphene oxide (GO). The SnO2-rGO hybrid composite was examined by scanning electron microscope and x-ray diffraction (XRD). The gas sensing properties of the SnO2-rGO composite were investigated at room temperature by exposing it to a wide concentration ranging from 1 ppm to 2000 ppm toward NO2 gas. The experiment results showed that the sensor exhibited a high response, superior selectivity, good repeatability, rapid response/recovery characteristics and low detection limit of 1 ppm, which exceeded that of a pure rGO sensor. The gas sensing mechanisms of the proposed sensor toward NO2 were possibly attributed to the nano-hybrid structures and n- p heterojunctions created at the interface of the SnO2 nanocrystals and rGO nanosheets.

  3. Influence of mineralizer agents on the growth of crystalline CeO{sub 2} nanospheres by the microwave-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Deus, R.C. [Universidade Estadual Paulista-Unesp - Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333 Bairro Portal das Colinas, CEP 12516-410 Guaratingueta-SP (Brazil); Cilense, M.; Foschini, C.R. [Universidade Estadual Paulista-Unesp - Instituto de Quimica - Laboratorio Interdisciplinar em Ceramica (LIEC), Rua Professor Francisco Degni s/n, CEP 14800-90 Araraquara, SP (Brazil); Ramirez, M.A. [Universidade Estadual Paulista-Unesp - Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333 Bairro Portal das Colinas, CEP 12516-410 Guaratingueta-SP (Brazil); Longo, E. [Universidade Estadual Paulista-Unesp - Instituto de Quimica - Laboratorio Interdisciplinar em Ceramica (LIEC), Rua Professor Francisco Degni s/n, CEP 14800-90 Araraquara, SP (Brazil); Simoes, A.Z., E-mail: alezipo@yahoo.com [Universidade Estadual Paulista-Unesp - Faculdade de Engenharia de Guaratingueta, Av. Dr. Ariberto Pereira da Cunha, 333 Bairro Portal das Colinas, CEP 12516-410 Guaratingueta-SP (Brazil); Universidade Federal de Itajuba-Unifei - Campus Itabira, Rua Sao Paulo, 377 Bairro Amazonas, CEP 35900-37 Itabira, MG (Brazil)

    2013-02-15

    Cystalline ceria (CeO{sub 2}) nanoparticles have been synthesized by a simple and fast microwave-assisted hydrothermal (MAH) under NaOH, KOH, and NH{sub 4}OH mineralizers added to a cerium ammonium nitrate aqueous solution. The products were characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transformed-IR and Raman spectroscopies. Rietveld refinement reveals a cubic structure with a space group Fm3m while infrared data showed few traces of nitrates. Field emission scanning microcopy (FEG-SEM) revealed a homogeneous size distribution of nanometric CeO{sub 2} nanoparticles. The MAH process in KOH and NaOH showed most effective to dehydrate the adsorbed water and decrease the hydrogen bonding effect leaving a weakly agglomerated powder of hydrated ceria. TEM micrographs of CeO{sub 2} synthesized under MAH conditions reveal particles well-dispersed and homogeneously distributed. The MAH enabled cerium oxide to be synthesized at 100 Degree-Sign C for 8 min.

  4. Syntheses of optically efficient (La{sub 1-x-y}Ce{sub x}Tb{sub y})F{sub 3} nanocrystals via a hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qiang [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); You Yumin; Ludescher, Richard D. [Department of Food Science, Rutgers University, New Brunswick, NJ 08901 (United States); Ju Yiguang, E-mail: yju@princeton.ed [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2010-06-15

    Optically efficient cerium and terbium doped lanthanide fluoride (La{sub 1-x-y}Ce{sub x}Tb{sub y})F{sub 3} nanocrystals with different doping concentrations have been synthesized by a hydrothermal route in the presence of ethylenediamine tetraacetic acid disodium salt (EDTA). The results showed that the formation of nanocrystals with different morphologies depends on terbium ion Tb{sup 3+} doping concentration, but independent of cerium ion Ce{sup 3+} doping concentration. With increase in Tb{sup 3+} doping concentration, the morphologies of nanocrystals evolved from a spherical shape to a plated-like one. In addition, both the photoluminescence quantum yield (PL QY) and the fluorescence lifetime of nanocrystals increased with the increase in Ce{sup 3+} doping concentration in cerium and terbium co-doped system. The PL QY reached up to 55%, and the lifetime up to 7.3 ms. Transmission electron microscopy (TEM), X-ray diffraction (XRD), selected area electron diffraction (SAED), X-ray fluorescence (XRF), energy dispersive spectroscopy (EDS), ultraviolet-visible (UV-vis) absorption, photoluminescence (PL) and infrared (IR) spectroscopies were employed to characterize the properties of nanocrystals. The growth mechanism of nanocrystals with different morphologies and optical properties of nanocrystals with different doping concentrations were investigated.

  5. Facile synthesis of antimony-doped tin oxide nanoparticles by a polymer-pyrolysis method

    International Nuclear Information System (INIS)

    Li, Yuan-Qing; Wang, Jian-Lei; Fu, Shao-Yun; Mei, Shi-Gang; Zhang, Jian-Min; Yong, Kang

    2010-01-01

    In this article, antimony-doped tin oxide (ATO) nanoparticles was synthesized by a facile polymer-pyrolysis method. The pyrolysis behaviors of the polymer precursors prepared via in situ polymerization of metal salts and acrylic acid were analyzed by simultaneous thermogravimetric and differential scanning calorimetry (TG-DSC). The structural and morphological characteristics of the products were studied by powder X-ray diffraction (XRD) and transmission electron microscope (TEM). The results reveal that the ATO nanoparticles calcined at 600 o C show good crystallinity with the cassiterite structure and cubic-spherical like morphology. The average particle size of ATO decreases from 200 to 15 nm as the Sb doping content increases from 5 mol% to 15 mol%. Electrical resistivity measurement shows that the resistivity for the 10-13 mol% Sb-doped SnO 2 nanoparticles is reduced by more than three orders compared with the pure SnO 2 nanoparticles. In addition, due to its versatility this polymer-pyrolysis method can be extended to facile synthesis of other doped n-type semiconductor, such as In, Ga, Al doped ZnO, Sn doped In 2 O 3 .

  6. Conservative method for determination of material thickness used in shielding of veterinary facilities

    International Nuclear Information System (INIS)

    Lava, Deise D.; Borges, Diogo da S.; Affonso, Renato R.W.; Moreira, Maria de L.; Guimaraes, Antonio C.F.

    2014-01-01

    For determination of an effective method for shielding of veterinary rooms, was provided shielding methods generally used in rooms which works with X-ray production and radiotherapy. Every calculation procedure is based in traditional variables used to transmission calculation. The thickness of the materials used for primary and secondary shieldings are obtained to respect the limits set by the Brazilian National Nuclear Energy Commission (CNEN). This work presents the development of a computer code in order to serve as a practical tool for determining rapid and effective materials and their thicknesses to shield veterinary facilities. The code determines transmission values of the shieldings and compares them with data from transmission 'maps' provided by NCRP-148 report. These 'maps' were added to the algorithm through interpolation techniques of curves of materials used for shielding. Each interpolation generates about 1,000,000 points that are used to generate a new curve. The new curve is subjected to regression techniques, which makes possible to obtain nine degree polynomial, and exponential equations. These equations whose variables consist of transmission of values, enable trace all the points of this curve with high precision. The data obtained from the algorithm were satisfactory with official data presented by the National Council of Radiation Protection and Measurements (NCRP) and can contribute as a practical tool for verification of shielding of veterinary facilities that require using Radiotherapy techniques and X-ray production

  7. Structural and magnetic properties of CoFe{sub 2}O{sub 4}/NiFe{sub 2}O{sub 4} core/shell nanocomposite prepared by the hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Sattar, A.A. [Department of Physics, Faculty of Science, Ain Shams University, 11566 Abbasia, Cairo (Egypt); EL-Sayed, H.M., E-mail: h_m_elsaid@hotmail.com [Department of Physics, Faculty of Science, Ain Shams University, 11566 Abbasia, Cairo (Egypt); ALsuqia, Ibrahim [Department of Physics, Faculty of Education and Applied Science, Hajjah University, Alshahli, Hajjah (Yemen)

    2015-12-01

    CoFe{sub 2}O{sub 4}/NiFe{sub 2}O{sub 4} core/shell magnetic nanocomposite was synthesized by using hydrothermal method.The analysis of XRD indicated the coexistence of CoFe{sub 2}O{sub 4}, NiFe{sub 2}O{sub 4}as core/shell composite. The core/shell structure of the composite sample has been confirmed by HR-TEM images, EDX and FT-IR measurements. The size of obtained core/shell nanoparticles was 17 nm in core diameter and about 3 nm in shell thickness. The magnetization measurements showed that both the coercive field and the saturation magnetization of the resulting core/shell nanocomposite were slightly decreased compared to those of the CoFe{sub 2}O{sub 4} core but the thermal stability is of the magnetization parameter was enhanced. Furthermore, superparamagnetic phase is established at temperatures higher than the room temperature. The results were discussed in terms of the surface pinning and the magnetic interaction at the interface between the core and shell. - Highlights: • CoFe{sub 2}O{sub 4}/NiFe{sub 2}O{sub 4} core/shell could be prepared by hydrothermal method. • The structural analysis proved the formation of NiFe{sub 2}O{sub 4} shell with thickness 3 nm. • The thermal stability of M{sub s} and H{sub c} is enhanced due to the presence of NiFe{sub 2}O{sub 4} as a shell. • Super paramagnetic transition is confirmed and the effective magnetic anisotropy was calculated.

  8. Analysis Methods for Extracting Knowledge from Large-Scale WiFi Monitoring to Inform Building Facility Planning

    DEFF Research Database (Denmark)

    Ruiz-Ruiz, Antonio; Blunck, Henrik; Prentow, Thor Siiger

    2014-01-01

    realistic data to inform facility planning. In this paper, we propose analysis methods to extract knowledge from large sets of network collected WiFi traces to better inform facility management and planning in large building complexes. The analysis methods, which build on a rich set of temporal and spatial......The optimization of logistics in large building com- plexes with many resources, such as hospitals, require realistic facility management and planning. Current planning practices rely foremost on manual observations or coarse unverified as- sumptions and therefore do not properly scale or provide....... Spatio-temporal visualization tools built on top of these methods enable planners to inspect and explore extracted information to inform facility-planning activities. To evaluate the methods, we present results for a large hospital complex covering more than 10 hectares. The evaluation is based on Wi...

  9. Facile and template-free method toward chemical synthesis of polyaniline film/nanotube structures

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Pei [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261; Zhu, Yisi [Materials Science Division, Argonne National Lab, Lemont Illinois 60439; Torres, Jorge [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261; Lee, Seung Hee [Department of BIN Fusion Technology, Chonbuk National University, Jeonju 561-786 Korea; Yun, Minhee [Department of Electrical and Computer Engineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh Pennsylvania 15261

    2017-09-05

    A facile and template-free method is reported to synthesize a new thin film structure: polyaniline (PANI) film/nanotubes (F/N) structure. The PANI F/N is a 100-nm thick PANI film embedded with PANI nanotubes. This well-controlled method requires no surfactant or organic acid as well as relatively low concentration of reagents. Synthesis condition studies reveal that aniline oligomers with certain structures are responsible for guiding the growth of the nanotubes. Electrical characterization also indicates that the PANI F/N possesses similar field-effect transistor characteristics to bare PANI film. With its 20% increased surface-area-to-volume (S/V) ratio contributed by surface embedded nanotubes and the excellent p-type semiconducting characteristic, PANI F/N shows clear superiority compared with bare PANI film. Such advantages guarantee the PANI F/N a promising future toward the development of ultra-high sensitivity and low-cost biosensors.

  10. Study of measurement method of tritium induced in concrete of high-energy proton accelerator facilities

    International Nuclear Information System (INIS)

    Ohtsuka, N.; Ishihama, S.; Kunifuda, T.; Hayasaka, N.; Miura, T.

    2001-01-01

    Various long-loved radionuclides, 3 H, 7 Be, 22 Na, 51 Cr, 54 Mn, 56 Co, 57 Co, 60 Co, 134 Cs, 152 Eu and 154 Eu, have been produced in the shielding concrete of high energy proton accelerator facility through both nuclear spallation reactions and thermal neutron capture reactions of concrete elements, during machine operation. Tritium is the most important nuclide from the radiation protection. There were, however, few measurements of tritium concentration induced in the shielding concrete. In this study, the conditions of measurement method of tritium concentration induced in shielding concrete have been investigated using the activated shielding concrete of the 12 GeV proton beam-line tunnel at KEK and the standard rock (JG-1) irradiated of thermal neutron at the reactor. And the depth profiles of tritium induced in the shielding concrete of slow extracted proton beam line at KEK were determined using this method. (author)

  11. A facile method to fabricate close-packed concave microlens array on cylindrical glass

    International Nuclear Information System (INIS)

    Deng, Zefang; Chen, Feng; Yang, Qing; Liu, Hewei; Bian, Hao; Du, Guangqing; Hu, Yang; Si, Jinhai; Meng, Xiangwei; Hou, Xun

    2012-01-01

    This work presents a facile method to fabricate concave microlens arrays (MLAs) with controllable shape and high fill factor on cylindrical silica glass by a femtosecond laser-enhanced chemical wet etching process. The hexagonal and rectangular MLAs are flexibly fabricated on the silica glass cylinder with a diameter of 3 mm. The morphological characteristics of MLAs are measured by a scanning electron microscope and a laser scanning confocal microscope. The measurements show that the good uniformity and high packing density MLA structures are generated. It has also been demonstrated that the shape and size of the concave structures could be easily tuned by changing laser power and the arrangement of laser exposure spots. The convex MLAs replicated by the polymer casting method experience excellent image quality. (paper)

  12. A facile method to prepare superhydrophobic fluorinated polysiloxane/ZnO nanocomposite coatings with corrosion resistance

    Science.gov (United States)

    Qing, Yongquan; Yang, Chuanning; Hu, Chuanbo; Zheng, Yansheng; Liu, Changsheng

    2015-01-01

    In this paper, we report a simple and inexpensive method for fabricating fluorinated polysiloxane/ZnO nanocomposite coatings on the steel substrates. The surface wettability and topology of coating were characterized by contact angle measurement, scanning electron microscope and Fourier transform infrared spectrometry. The results showed that the hydrophobic sbnd CH3 and sbnd CH2sbnd groups were introduced into ZnO particles via modification, the ZnO nanoparticles were modified from hydrophilic to hydrophobic. When the weight ratio of modified-ZnO to fluorinated polysiloxane was 13:7, the contact angle of nanocomposite coating was 166°, and a sliding angle of 4°, coating surface with hierarchical micro/nano-structures. In addition, the as-prepared superhydrophobic surface has excellent durability and corrosion resistance. It is believed that the facile and low-cost method offer an effective strategy and promising industrial applications for fabricating superhydrophobic surfaces on steel materials.

  13. Advanced methods comparisons of reaction rates in the Purdue Fast Breeder Blanket Facility

    International Nuclear Information System (INIS)

    Hill, R.N.; Ott, K.O.

    1988-01-01

    A review of worldwide results revealed that reaction rates in the blanket region are generally underpredicted with the discrepancy increasing with penetration; however, these results vary widely. Experiments in the large uniform Purdue Fast Breeder Blanket Facility (FBBF) blanket yield an accurate quantification of this discrepancy. Using standard production code methods (diffusion theory with 50 group cross sections), a consistent Calculated/Experimental (C/E) drop-off was observed for various reaction rates. A 50% increase in the calculated results at the outer edge of the blanket is necessary for agreement with experiments. The usefulness of refined group constant generation utilizing specialized weighting spectra and transport theory methods in correcting this discrepancy was analyzed. Refined group constants reduce the discrepancy to half that observed using the standard method. The surprising result was that transport methods had no effect on the blanket deviations; thus, transport theory considerations do not constitute or even contribute to an explanation of the blanket discrepancies. The residual blanket C/E drop-off (about half the standard drop-off) using advanced methods must be caused by some approximations which are applied in all current methods. 27 refs., 3 figs., 1 tab

  14. Novel Biocontrol Methods for Listeria monocytogenes Biofilms in Food Production Facilities

    Directory of Open Access Journals (Sweden)

    Jessica A. Gray

    2018-04-01

    Full Text Available High mortality and hospitalization rates have seen Listeria monocytogenes as a foodborne pathogen of public health importance for many years and of particular concern for high-risk population groups. Food manufactures face an ongoing challenge in preventing the entry of L. monocytogenes into food production environments (FPEs due to its ubiquitous nature. In addition to this, the capacity of L. monocytogenes strains to colonize FPEs can lead to repeated identification of L. monocytogenes in FPE surveillance. The contamination of food products requiring product recall presents large economic burden to industry and is further exacerbated by damage to the brand. Poor equipment design, facility layout, and worn or damaged equipment can result in Listeria hotspots and biofilms where traditional cleaning and disinfecting procedures may be inadequate. Novel biocontrol methods may offer FPEs effective means to help improve control of L. monocytogenes and decrease cross contamination of food. Bacteriophages have been used as a medical treatment for many years for their ability to infect and lyse specific bacteria. Endolysins, the hydrolytic enzymes of bacteriophages responsible for breaking the cell wall of Gram-positive bacteria, are being explored as a biocontrol method for food preservation and in nanotechnology and medical applications. Antibacterial proteins known as bacteriocins have been used as alternatives to antibiotics for biopreservation and food product shelf life extension. Essential oils are natural antimicrobials formed by plants and have been used as food additives and preservatives for many years and more recently as a method to prevent food spoilage by microorganisms. Competitive exclusion occurs naturally among bacteria in the environment. However, intentionally selecting and applying bacteria to effect competitive exclusion of food borne pathogens has potential as a biocontrol application. This review discusses these novel biocontrol

  15. Novel Biocontrol Methods for Listeria monocytogenes Biofilms in Food Production Facilities.

    Science.gov (United States)

    Gray, Jessica A; Chandry, P Scott; Kaur, Mandeep; Kocharunchitt, Chawalit; Bowman, John P; Fox, Edward M

    2018-01-01

    High mortality and hospitalization rates have seen Listeria monocytogenes as a foodborne pathogen of public health importance for many years and of particular concern for high-risk population groups. Food manufactures face an ongoing challenge in preventing the entry of L. monocytogenes into food production environments (FPEs) due to its ubiquitous nature. In addition to this, the capacity of L. monocytogenes strains to colonize FPEs can lead to repeated identification of L. monocytogenes in FPE surveillance. The contamination of food products requiring product recall presents large economic burden to industry and is further exacerbated by damage to the brand. Poor equipment design, facility layout, and worn or damaged equipment can result in Listeria hotspots and biofilms where traditional cleaning and disinfecting procedures may be inadequate. Novel biocontrol methods may offer FPEs effective means to help improve control of L. monocytogenes and decrease cross contamination of food. Bacteriophages have been used as a medical treatment for many years for their ability to infect and lyse specific bacteria. Endolysins, the hydrolytic enzymes of bacteriophages responsible for breaking the cell wall of Gram-positive bacteria, are being explored as a biocontrol method for food preservation and in nanotechnology and medical applications. Antibacterial proteins known as bacteriocins have been used as alternatives to antibiotics for biopreservation and food product shelf life extension. Essential oils are natural antimicrobials formed by plants and have been used as food additives and preservatives for many years and more recently as a method to prevent food spoilage by microorganisms. Competitive exclusion occurs naturally among bacteria in the environment. However, intentionally selecting and applying bacteria to effect competitive exclusion of food borne pathogens has potential as a biocontrol application. This review discusses these novel biocontrol methods and their

  16. Novel Biocontrol Methods for Listeria monocytogenes Biofilms in Food Production Facilities

    Science.gov (United States)

    Gray, Jessica A.; Chandry, P. Scott; Kaur, Mandeep; Kocharunchitt, Chawalit; Bowman, John P.; Fox, Edward M.

    2018-01-01

    High mortality and hospitalization rates have seen Listeria monocytogenes as a foodborne pathogen of public health importance for many years and of particular concern for high-risk population groups. Food manufactures face an ongoing challenge in preventing the entry of L. monocytogenes into food production environments (FPEs) due to its ubiquitous nature. In addition to this, the capacity of L. monocytogenes strains to colonize FPEs can lead to repeated identification of L. monocytogenes in FPE surveillance. The contamination of food products requiring product recall presents large economic burden to industry and is further exacerbated by damage to the brand. Poor equipment design, facility layout, and worn or damaged equipment can result in Listeria hotspots and biofilms where traditional cleaning and disinfecting procedures may be inadequate. Novel biocontrol methods may offer FPEs effective means to help improve control of L. monocytogenes and decrease cross contamination of food. Bacteriophages have been used as a medical treatment for many years for their ability to infect and lyse specific bacteria. Endolysins, the hydrolytic enzymes of bacteriophages responsible for breaking the cell wall of Gram-positive bacteria, are being explored as a biocontrol method for food preservation and in nanotechnology and medical applications. Antibacterial proteins known as bacteriocins have been used as alternatives to antibiotics for biopreservation and food product shelf life extension. Essential oils are natural antimicrobials formed by plants and have been used as food additives and preservatives for many years and more recently as a method to prevent food spoilage by microorganisms. Competitive exclusion occurs naturally among bacteria in the environment. However, intentionally selecting and applying bacteria to effect competitive exclusion of food borne pathogens has potential as a biocontrol application. This review discusses these novel biocontrol methods and their

  17. METHODS FOR DETERMINING AGITATOR MIXING REQUIREMENTS FOR A MIXING and SAMPLING FACILITY TO FEED WTP (WASTE TREATMENT PLANT)

    International Nuclear Information System (INIS)

    Griffin, P.W.

    2009-01-01

    The following report is a summary of work conducted to evaluate the ability of existing correlative techniques and alternative methods to accurately estimate impeller speed and power requirements for mechanical mixers proposed for use in a mixing and sampling facility (MSF). The proposed facility would accept high level waste sludges from Hanford double-shell tanks and feed uniformly mixed high level waste to the Waste Treatment Plant. Numerous methods are evaluated and discussed, and resulting recommendations provided.

  18. METHODS FOR DETERMINING AGITATOR MIXING REQUIREMENTS FOR A MIXING & SAMPLING FACILITY TO FEED WTP (WASTE TREATMENT PLANT)

    Energy Technology Data Exchange (ETDEWEB)

    GRIFFIN PW

    2009-08-27

    The following report is a summary of work conducted to evaluate the ability of existing correlative techniques and alternative methods to accurately estimate impeller speed and power requirements for mechanical mixers proposed for use in a mixing and sampling facility (MSF). The proposed facility would accept high level waste sludges from Hanford double-shell tanks and feed uniformly mixed high level waste to the Waste Treatment Plant. Numerous methods are evaluated and discussed, and resulting recommendations provided.

  19. A fuzzy logic based method to monitor organizational resilience: application in a brazilian radioactive facility

    International Nuclear Information System (INIS)

    Grecco, Claudio H.S.; Santos, Isaac J.A.L.; Carvalho, Paulo V.R.; Vidal, Mario C.R.; Cosenza, Carlos A.N.

    2013-01-01

    Resilience is the intrinsic ability of a system to adjust its functioning prior to, during, or following changes and disturbances, so that it can sustain required operations under expected and unexpected conditions. This definition focuses on the ability to function, rather than on being impervious to failure, and thereby overcomes the traditional conflict between productivity and safety. Resilience engineering (RE) has fast become recognized as a valuable complement to the established approaches to safety of complex socio-technical systems and methods to monitor organizational resilience are needed. However, few, if any, comprehensive and systematic research studies focus on developing an objective, reliable and practical assessment model for monitoring organizational resilience. Most methods cannot fully solve the subjectivity of resilience evaluation. In order to remedy this deficiency, the aim of this research is to adopt a Fuzzy Set Theory (FST) approach to establish a method for resilience assessment in organizations based on leading safety performance indicators, defined according to the resilience engineering principles. The method uses FST concepts and properties to model the indicators and to assess the results of their application. To exemplify the method we performed an exploratory case study at the process of radiopharmaceuticals dispatch package of a Brazilian radioactive facility. (author)

  20. Virtual reality based adaptive dose assessment method for arbitrary geometries in nuclear facility decommissioning.

    Science.gov (United States)

    Liu, Yong-Kuo; Chao, Nan; Xia, Hong; Peng, Min-Jun; Ayodeji, Abiodun

    2018-05-17

    This paper presents an improved and efficient virtual reality-based adaptive dose assessment method (VRBAM) applicable to the cutting and dismantling tasks in nuclear facility decommissioning. The method combines the modeling strength of virtual reality with the flexibility of adaptive technology. The initial geometry is designed with the three-dimensional computer-aided design tools, and a hybrid model composed of cuboids and a point-cloud is generated automatically according to the virtual model of the object. In order to improve the efficiency of dose calculation while retaining accuracy, the hybrid model is converted to a weighted point-cloud model, and the point kernels are generated by adaptively simplifying the weighted point-cloud model according to the detector position, an approach that is suitable for arbitrary geometries. The dose rates are calculated with the Point-Kernel method. To account for radiation scattering effects, buildup factors are calculated with the Geometric-Progression formula in the fitting function. The geometric modeling capability of VRBAM was verified by simulating basic geometries, which included a convex surface, a concave surface, a flat surface and their combination. The simulation results show that the VRBAM is more flexible and superior to other approaches in modeling complex geometries. In this paper, the computation time and dose rate results obtained from the proposed method were also compared with those obtained using the MCNP code and an earlier virtual reality-based method (VRBM) developed by the same authors. © 2018 IOP Publishing Ltd.

  1. A fuzzy logic based method to monitor organizational resilience: application in a brazilian radioactive facility

    Energy Technology Data Exchange (ETDEWEB)

    Grecco, Claudio H.S.; Santos, Isaac J.A.L.; Carvalho, Paulo V.R., E-mail: grecco@ien.gov.br, E-mail: luquetti@ien.gov.br, E-mail: paulov@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Divisao de Instrumentacao e Confiabilidade Humana; Vidal, Mario C.R.; Cosenza, Carlos A.N., E-mail: mvidal@ergonomia.ufrj.br, E-mail: cosenza@pep.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEP/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia de Producao

    2013-07-01

    Resilience is the intrinsic ability of a system to adjust its functioning prior to, during, or following changes and disturbances, so that it can sustain required operations under expected and unexpected conditions. This definition focuses on the ability to function, rather than on being impervious to failure, and thereby overcomes the traditional conflict between productivity and safety. Resilience engineering (RE) has fast become recognized as a valuable complement to the established approaches to safety of complex socio-technical systems and methods to monitor organizational resilience are needed. However, few, if any, comprehensive and systematic research studies focus on developing an objective, reliable and practical assessment model for monitoring organizational resilience. Most methods cannot fully solve the subjectivity of resilience evaluation. In order to remedy this deficiency, the aim of this research is to adopt a Fuzzy Set Theory (FST) approach to establish a method for resilience assessment in organizations based on leading safety performance indicators, defined according to the resilience engineering principles. The method uses FST concepts and properties to model the indicators and to assess the results of their application. To exemplify the method we performed an exploratory case study at the process of radiopharmaceuticals dispatch package of a Brazilian radioactive facility. (author)

  2. Effect of hydrothermal process for inorganic alumina sol on crystal structure of alumina gel

    Directory of Open Access Journals (Sweden)

    K. Yamamura

    2016-09-01

    Full Text Available This paper reports the effect of a hydrothermal process for alumina sol on the crystal structure of alumina gel derived from hydrothermally treated alumina sol to help push forward the development of low temperature synthesis of α-Al2O3. White precipitate of aluminum hydroxide was prepared with a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution. The obtained aluminum hydroxide precipitate was peptized by using acetic acid at room temperature, which resulted in the production of a transparent alumina sol. The alumina sol was treated with a hydrothermal process and transformed into an alumina gel film by drying at room temperature. Crystallization of the alumina gel to α-Al2O3 with 900 °C annealing was dominant for a hydrothermal temperature of 100 °C and a hydrothermal time of 60 min, as production of diaspore-like species was promoted with the hydrothermal temperature and time. Excess treatments with hydrothermal processes at higher hydrothermal temperature for longer hydrothermal time prevented the alumina gel from being crystallized to α-Al2O3 because the excess hydrothermal treatments promoted production of boehmite.

  3. A facile method for electrospinning of Ag nanoparticles/poly (vinyl alcohol)/carboxymethyl-chitosan nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yinghui; Zhou, Ying [Beijing Key Laboratory for Solid Waste Utilization and Management, College of Engineering, Peking University, Beijing 100871 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Wu, Xiaomian [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Department of Orthodontics College of Stomatology, Chongqing Medical University, Chongqing 401147 (China); Wang, Lu [Beijing Key Laboratory for Solid Waste Utilization and Management, College of Engineering, Peking University, Beijing 100871 (China); Xu, Ling, E-mail: lingxu@pku.edu.cn [Beijing Key Laboratory for Solid Waste Utilization and Management, College of Engineering, Peking University, Beijing 100871 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); PKU-HKUST ShenZhen-HongKong Institution, Shenzhen 518057 (China); Wei, Shicheng, E-mail: sc-wei@pku.edu.cn [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, Peking University, Beijing 100081 (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer AgNPs/PVA/CM-chitosan nanofibers were prepared via electrospinning method. Black-Right-Pointing-Pointer AgNPs were in situ synthesized in electrospinning solution via a facile method. Black-Right-Pointing-Pointer AgNPs distributed homogeneously on the surface of nanofibers. Black-Right-Pointing-Pointer The prepared nanofibers possessed certain antibacterial ability against Escherichia coli. Black-Right-Pointing-Pointer The AgNPs containing nanofibers had potential as antibacterial biomaterial. - Abstract: A facile method to prepare silver nanoparticles (AgNPs) containing nanofibers via electrospinning has been demonstrated. AgNPs were in situ synthesized in poly (vinyl alcohol) (PVA)/carboxymethyl-chitosan (CM-chitosan) blend aqueous solution before electrospinning. UV-vis spectra, viscosity and conductivity of the electrospinning solution were measured to investigate their effects on the electrospinning procedure. The morphology of AgNPs/PVA/CM-chitosan nanofibers was observed by Field Emission Scanning Electron Microscopy. The formation and morphology of AgNPs were investigated by Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. The resulted nanofibers have smooth surface and uniform diameters ranging from 295 to 343 nm. The diameters of AgNPs mainly distributed in the range of 4-14 nm, and the electrostatic interaction between AgNPs and fibers was observed. Finally, in vitro Ag release from the nanofibers was measured and the antibacterial behavior of the nanofibers against Escherichia coli was studied by bacterial growth inhibition halos and bactericidal kinetic testing. The AgNPs/PVA/CM-chitosan nanofibers possessed certain antibacterial ability, which makes them capable for antibacterial biomaterials.

  4. A facile method for electrospinning of Ag nanoparticles/poly (vinyl alcohol)/carboxymethyl-chitosan nanofibers

    International Nuclear Information System (INIS)

    Zhao, Yinghui; Zhou, Ying; Wu, Xiaomian; Wang, Lu; Xu, Ling; Wei, Shicheng

    2012-01-01

    Highlights: ► AgNPs/PVA/CM-chitosan nanofibers were prepared via electrospinning method. ► AgNPs were in situ synthesized in electrospinning solution via a facile method. ► AgNPs distributed homogeneously on the surface of nanofibers. ► The prepared nanofibers possessed certain antibacterial ability against Escherichia coli. ► The AgNPs containing nanofibers had potential as antibacterial biomaterial. - Abstract: A facile method to prepare silver nanoparticles (AgNPs) containing nanofibers via electrospinning has been demonstrated. AgNPs were in situ synthesized in poly (vinyl alcohol) (PVA)/carboxymethyl-chitosan (CM-chitosan) blend aqueous solution before electrospinning. UV–vis spectra, viscosity and conductivity of the electrospinning solution were measured to investigate their effects on the electrospinning procedure. The morphology of AgNPs/PVA/CM-chitosan nanofibers was observed by Field Emission Scanning Electron Microscopy. The formation and morphology of AgNPs were investigated by Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. The resulted nanofibers have smooth surface and uniform diameters ranging from 295 to 343 nm. The diameters of AgNPs mainly distributed in the range of 4–14 nm, and the electrostatic interaction between AgNPs and fibers was observed. Finally, in vitro Ag release from the nanofibers was measured and the antibacterial behavior of the nanofibers against Escherichia coli was studied by bacterial growth inhibition halos and bactericidal kinetic testing. The AgNPs/PVA/CM-chitosan nanofibers possessed certain antibacterial ability, which makes them capable for antibacterial biomaterials.

  5. Modular head assembly and method of retrofitting existing nuclear reactor facilities

    International Nuclear Information System (INIS)

    Malandra, L.J.; Ledue, R.J.; Hankinson, M.F.; Kowalski, E.F.

    1987-01-01

    A method is described of retrofitting existing nuclear reactor facilities so as to form a modular closure head assembly for a nuclear reactor pressure vessel, where the existing nuclear reactor facilities comprise control rod drive mechanism cooling systems which include vertically extending elbow air ducts inter-connecting vertically spaced upper and lower air manifolds. The elbow air ducts extend radially beyond the peripheral envelope of the closure head, comprising the steps of: removing the upper air manifold; removing the vertically extending elbow air ducts; capping the air ports of the lower air manifold which ports were previously fluidically connecting the lower air manifold to the vertically extending elbow air ducts; disposing vertically upwardly extending air exhaust ducts above the lower air manifold in such an manner that the air exhaust ducts are disposed within the peripheral envelope of the closure head; fluidically connecting exhaust fans to the upper regions of the air exhaust ducts; fluidically connecting the lower regions of the air exhaust ducts the lower air manifold; permanently securing lift rods to the closure head at positions disposed radially outwardly of the lower air manifold; attaching a seismic support platform to the lift rods; proving fluidic passage of the vertically extending air exhaust ducts through the seismic support platform; attaching a missile shield plate to the lift rods; and proving fluidic passage of the vertically extending air exhaust ducts through the missile shield plate

  6. Scenarios and analytical methods for UF6 releases at NRC-licensed fuel cycle facilities

    International Nuclear Information System (INIS)

    Siman-Tov, M.; Dykstra, J.; Holt, D.D.; Huxtable, W.P.; Just, R.A.; Williams, W.R.

    1984-06-01

    This report identifies and discusses potential scenarios for the accidental release of UF 6 at NRC-licensed UF 6 production and fuel fabrication facilities based on a literature review, site visits, and DOE enrichment plant experience. Analytical tools needed for evaluating source terms for such releases are discussed, and the applicability of existing methods is reviewed. Accident scenarios are discussed under the broad headings of cylinder failures, UF 6 process system failures, nuclear criticality events, and operator errors and are categorized by location, release source, phase of UF 6 prior to release, release flow characteristics, release causes, initiating events, and UF 6 inventory at risk. At least three types of releases are identified for further examination: (1) a release from a liquid-filled cylinder outdoors, (2) a release from a pigtail or cylinder in a steam chest, (3) an indoor release from either (a) a pigtail or liquid-filled cylinder or (b) other indoor source depending on facility design and operating procedures. Indoor release phenomena may be analyzed to determine input terms for a ventilation model by using a time-dependent homogeneous compartment model or a more complex hydrodynamic model if time-dependent, spatial variations in concentrations, temperature, and pressure are important. Analytical tools for modeling directed jets and explosive releases are discussed as well as some of the complex phenomena to be considered in analyzing UF 6 releases both indoors and outdoors

  7. Hydrothermal Growth of Polyscale Crystals

    Science.gov (United States)

    Byrappa, Kullaiah

    In this chapter, the importance of the hydrothermal technique for growth of polyscale crystals is discussed with reference to its efficiency in synthesizing high-quality crystals of various sizes for modern technological applications. The historical development of the hydrothermal technique is briefly discussed, to show its evolution over time. Also some of the important types of apparatus used in routine hydrothermal research, including the continuous production of nanosize crystals, are discussed. The latest trends in the hydrothermal growth of crystals, such as thermodynamic modeling and understanding of the solution chemistry, are elucidated with appropriate examples. The growth of some selected bulk, fine, and nanosized crystals of current technological significance, such as quartz, aluminum and gallium berlinites, calcite, gemstones, rare-earth vanadates, electroceramic titanates, and carbon polymorphs, is discussed in detail. Future trends in the hydrothermal technique, required to meet the challenges of fast-growing demand for materials in various technological fields, are described. At the end of this chapter, an Appendix 18.A containing a more or less complete list of the characteristic families of crystals synthesized by the hydrothermal technique is given with the solvent and pressure-temperature (PT) conditions used in their synthesis.

  8. Study of applicable methods on safety verification of disposal facilities and waste packages

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    Three subjects about safety verification on the disposal of low level radioactive waste were investigated in FY. 2012. For radioactive waste disposal facilities, specs and construction techniques of covering with soil to prevent possible destruction caused by natural events (e.g. earthquake) were studied to consider verification methods for those specs. For waste packages subject to near surface pit disposal, settings of scaling factor and average radioactivity concentration (hereafter referred to as ''SF'') on container-filled and solidified waste packages generated from Kashiwazaki Kariwa Nuclear Power Station Unit 1-5, setting of cesium residual ratio of molten solidified waste generated from Tokai and Tokai No.2 Power Stations, etc. were studied. Those results were finalized in consideration of the opinion from advisory panel, and publicly opened as JNES-EV reports. In FY 2012, five JNES reports were published and these have been used as standards of safety verification on waste packages. The verification method of radioactive wastes subject to near-surface trench disposal and intermediate depth disposal were also studied. For radioactive wastes which will be returned from overseas, determination methods of radioactive concentration, heat rate and hydrogen generation rate of CSD-C were established. Determination methods of radioactive concentration and heat rate of CSD-B were also established. These results will be referred to verification manuals. (author)

  9. A dose assessment method for arbitrary geometries with virtual reality in the nuclear facilities decommissioning

    Science.gov (United States)

    Chao, Nan; Liu, Yong-kuo; Xia, Hong; Ayodeji, Abiodun; Bai, Lu

    2018-03-01

    During the decommissioning of nuclear facilities, a large number of cutting and demolition activities are performed, which results in a frequent change in the structure and produce many irregular objects. In order to assess dose rates during the cutting and demolition process, a flexible dose assessment method for arbitrary geometries and radiation sources was proposed based on virtual reality technology and Point-Kernel method. The initial geometry is designed with the three-dimensional computer-aided design tools. An approximate model is built automatically in the process of geometric modeling via three procedures namely: space division, rough modeling of the body and fine modeling of the surface, all in combination with collision detection of virtual reality technology. Then point kernels are generated by sampling within the approximate model, and when the material and radiometric attributes are inputted, dose rates can be calculated with the Point-Kernel method. To account for radiation scattering effects, buildup factors are calculated with the Geometric-Progression formula in the fitting function. The effectiveness and accuracy of the proposed method was verified by means of simulations using different geometries and the dose rate results were compared with that derived from CIDEC code, MCNP code and experimental measurements.

  10. Progress in the study of PCHE performance with various stacking methods; PCHEs and test facility

    International Nuclear Information System (INIS)

    Kim, Ji Eun; Kim, Eun Ho; Yoon, Sung Ho; Kim, Moo Hwan; Park, Gun Yeop

    2012-01-01

    Printed Circuit Heat Exchanger (PCHE) is famous with its superior compactness and relatively higher resistance to pressure which came from its manufacturing process. PCHE is made by diffusion bonding of thin metal plates having various flow channel shapes on them. Diffusion bonding makes stack of plates become a monolithic block by grain growth between the surfaces of each plates near the melting temperature of material. With these characteristics, it has become a promising heat exchanger type in oil and gas industry, power plant and chemical reactors fields, despite of its relatively short history than others. From many researches, it is known that the flow channel and the stacking method of plates are the major design factors of PCHE. Flow channels have been studied by relatively many researchers, and there are several well known channel types like zigzag channel, S shape fin, and airfoil fin shape. On the other hands, there is little research about stacking method so called 'bank type'. By Kim et al., it was showed that stacking method of PCHE influences the heat transfer rate and pressure drop, but the comparison of the different stacking method was not conducted. In this research, heat transfer and pressure drop characteristics of PCHEs with various bank types will be studied. And this article will introduce three kinds of PCHEs fabricated by different bank types, and the test facility for performance test of these heat exchangers

  11. Use of risk-matrix methods in the radiation safety analysis of PET/CT facilities

    International Nuclear Information System (INIS)

    Calderón Marín, Carlos F.; González González, Joaquín J.; Quesada Cepero, Waldo; Sinconegui Gómez, Belkys; Solá Rodríguez, Yeline; Duménigo Ámbar, Cruz; Guerrero Cancio, Mayka

    2016-01-01

    Introduction. Radiological safety is essential during clinical applications of ionizing radiations. Cuban legislation considers it mandatory to carry out risk analysis during safety assessments of facilities where Nuclear Medicine practices are performed. The Risk Matrix (R-M) method has been used in risk assessments in Radiotherapy and some experiences in Nuclear Medicine have been reported. In the present work the results of the safety evaluation, using the M-R method, of the first PET / CT center constructed at the Institute of Oncology and Radiobiology in Havana, are shown. The facilities will work as a satellite center and the production of radioactive drugs of 68 Ga will be conceived. The images will be acquired with a Philips Gemini TF64 scanner. Several stages and sub-stages were considered, including the design of the facility, quality control programs, review of the relevance of study requests, radiopharmaceutical reception and fractionation, 68 Ga radiopharmaceuticals production, management of Patient during the administration of radiopharmaceuticals and patient positioning. Initiating events (IEs), available barriers, as well as measures for the reduction of frequency (RFMs) of IEs and consequences (RCMs) were identified. In addition, IEs sequences are considered for CT scans. The incidence of risk reduction was assessed by the ratio of the number of times they were used and the total number of IEs. The calculation of the R-M was made by modeling the practice with the SEVRRA code R iskAssessmentSystem . Results. As a result, 76 IEs were identified with a distribution of 72% affecting patients, 7.9% in the Public and 19.7% on Occupationally Exposed Workers (TOEs). 89.5% of IEs are caused by human errors. Barriers and consequences and frequency reducers produced a risk distribution of 2.6% of high risk IEs, 64.5% medium risk and 32.9% low risk. The high-risk IEs are related to errors in the calculation of the shielding requirements of the facility that

  12. Hydrothermal treatment of coprecipitated YSZ powders

    International Nuclear Information System (INIS)

    Arakaki, Alexander Rodrigo; Yoshito, Walter Kenji; Ussui, Valter; Lazar, Dolores Ribeiro Ricci

    2009-01-01

    Zirconia stabilized with 8.5 mol% yttria (YSZ) were synthesized by coprecipitation and resulting gels were hydrothermally treated at 200°C and 220 PSI for 4, 8 and 16 hours. Products were oven dried at 70°C for 24 hours, uniaxially pressed as pellets and sintered at 1500 °C for 1 hour. Powders were characterized for surface area with N 2 gas adsorption, X-ray diffraction, laser diffraction granulometric analysis and scanning and transmission electronic microscopy. Density of ceramics was measured by an immersion method based on the Archimedes principle. Results showed that powders dried at 70°C are amorphous and after treatment has tetragonal/cubic symmetry. Surface area of powders presented a significant reduction after hydrothermal treatment. Ceramics prepared from hydrothermally treated powders have higher green density but sintered pellets are less dense when compared to that made with powders calcined at 800°C for 1 hour due to the agglomerate state of powders. Solvothermal treatment is a promising procedure to enhance density. (author)

  13. A method for predicting the impact velocity of a projectile fired from a compressed air gun facility

    International Nuclear Information System (INIS)

    Attwood, G.J.

    1988-03-01

    This report describes the development and use of a method for calculating the velocity at impact of a projectile fired from a compressed air gun. The method is based on a simple but effective approach which has been incorporated into a computer program. The method was developed principally for use with the Horizontal Impact Facility at AEE Winfrith but has been adapted so that it can be applied to any compressed air gun of a similar design. The method has been verified by comparison of predicted velocities with test data and the program is currently being used in a predictive manner to specify test conditions for the Horizontal Impact Facility at Winfrith. (author)

  14. Tsunami risk assessment for facility group over a wide area using inundation assessment method considering energy conservation law

    International Nuclear Information System (INIS)

    Fukutani, Yo; Imamura, Fumihiko; Tokunaga, Takeshi; Sato, Ichiro

    2015-01-01

    We propose a quantitative evaluation method of overall tsunami risk that the entire facility group over a wide area holds. We considerably reduced the calculation cost for tsunami inundation depth by adopting the evaluation method using energy conservation law as compared with the evaluation method using non-linear long wave equation. For financial institutions such as banks and insurance companies with contractors over a wide area and business companies with multiple their assets and facilities in various places, the proposed evaluation method in this study could be a useful approach to implement their risk-based management decisions for tsunami risk. (author)

  15. A facile method to align carbon nanotubes on polymeric membrane substrate

    Science.gov (United States)

    Zhao, Haiyang; Zhou, Zhijun; Dong, Hang; Zhang, Lin; Chen, Huanlin; Hou, Lian

    2013-01-01

    The alignment of carbon nanotubes (CNT) is the fundamental requirement to ensure their excellent functions but seems to be desolated in recent years. A facile method, hot-press combined with peel-off (HPPO), is introduced here, through which CNT can be successfully vertically aligned on the polymeric membrane substrate. Shear force and mechanical stretch are proposed to be the main forces to align the tubes perpendicular to the substrate surface during the peel-off process. The alignment of CNT keeps its orientation in a thin hybrid membrane by dip-coating cellulose acetate dope solution. It is expected that the stable alignment of CNT by HPPO would contribute to the realization of its potential applications. PMID:24326297

  16. Radon and radon daughter measurements and methods utilized by EPA's Eastern Environmental Radiation Facility

    International Nuclear Information System (INIS)

    Phillips, C.R.

    1977-01-01

    The Eastern Environmental Radiation Facility (EERF), Office of Radiation Programs, has the responsibility for conducting the Environmental Protection Agency's study of the radiological impact of the phosphate industry. Numerous measurements in structures constructed on land reclaimed from phosphate mining showed that working levels in these structures range from 0.001 to 0.9 WL. Sampling is performed by drawing air through a 0.8 micrometer pore size, 25 mm diameter filter at a flow rate of 10 to 15 liters/minute for from 5 to 20 minutes, depending on the daughter levels anticipated. The detection system consists of a ruggedized silicon surface barrier detector (450 mm 2 -100 micrometer depletion) connected through an appropriate pre-amplifier-amplifier to a 1024-channel multichannel analyzer. Other measurement methods are also discussed

  17. Facile method for liquid-exfoliated graphene size prediction by UV-visible spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Zulhelmi, E-mail: helmie83@hotmail.com [Faculty of Manufacturing Engineering, Universiti Malaysia Pahang, 26600 Pekan, Pahang (Malaysia); Yusoh, Kamal, E-mail: kamal@ump.edu.my [Faculty of Chemical Engineering and Natural Resources, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Kuantan, Pahang (Malaysia)

    2016-07-19

    In this work, an application of UV spectroscopy for facile prediction of liquid –exfoliated graphene size is discussed. Dynamic light scattering method was used to estimate the graphene flake size ( whilst UV spectroscopy measurement was carried out for extinction coefficient value (ε) determination. It was found that the value of (ε) decreased gradually as the graphene size was further reduced after intense sonication time (7h). This observation showed the influence of sonication time on electronic structure of graphene. A mathematical equation was derived from log-log graph for correlation between () and (ε) value. Both values can be expressed in a single equation as ( = (3.4 × 10{sup −2}) ε{sup 1.2}).

  18. A novel, efficient and facile method for the template removal from mesoporous materials

    KAUST Repository

    Chen, Lu

    2014-11-12

    © 2014, Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH. A new catalytic-oxidation method was adopted to remove the templates from SBA-15 and MCM-41 mesoporous materials via Fenton-like techniques under microwave irradiation. The mesoporous silica materials were treated with different Fenton agents based on the template’s property and textural property. The samples were characterized by powder X-ray diffraction(XRD) measurement, N2 adsorption-desorption isotherms, infrared spectroscopy, 29Si MAS NMR and thermo gravimetric analysis(TGA). The results reveal that this is an efficient and facile approach to the thorough template-removal from mesoporous silica materials, as well as to offering products with more stable structures, higher BET surface areas, larger pore volumes and larger quantity of silanol groups.

  19. Facile method to fabricate raspberry-like particulate films for superhydrophobic surfaces.

    Science.gov (United States)

    Tsai, Hui-Jung; Lee, Yuh-Lang

    2007-12-04

    A facile method using layer-by-layer assembly of silica particles is proposed to prepare raspberry-like particulate films for the fabrication of superhydrophobic surfaces. Silica particles 0.5 microm in diameter were used to prepare a surface with a microscale roughness. Nanosized silica particles were then assembled on the particulate film to construct a finer structure on top of the coarse one. After surface modification with dodecyltrichlorosilane, the advancing and receding contact angles of water on the dual-sized structured surface were 169 and 165 degrees , respectively. The scale ratio of the micro/nano surface structure and the regularity of the particulate films on the superhydrophobic surface performance are discussed.

  20. Development of thermal mixing enhancement method for lower plenum of the High Temperature Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    Gradecka, Malwina Joanna, E-mail: malgrad@gmail.com; Woods, Brian G., E-mail: brian.woods@oregonstate.edu

    2016-08-15

    Highlights: • Coolant mixing in lower plenum might be insufficient and pose operational issues. • Two mixing methods were developed to lower the coolant temperature variation. • The methods resulted with reduction of the temperature variation by 60% and 71%. - Abstract: The High Temperature Gas-cooled Reactor (HTGR) is one of the most mature Gen IV reactor concepts under development today. The High Temperature Test Facility (HTTF) at Oregon State University is a test facility that supports the R&D needs for HTGRs. This study focuses on the issue of helium mixing after the core section in the HTTF, the results of which are generally applicable in HTGRs. In the HTTF, hot helium jets at different temperatures are supposed to uniformly mix in the lower plenum (LP) chamber. However, the level of mixing is not sufficient to reduce the peak helium temperature before the hot jet impinges the LP structure, which can cause issues with structural materials and operational issues in the heat exchanger downstream. The maximum allowable temperature variation in the outlet duct connected to the lower plenum is defined as 40 K (±20 K from the average temperature), while the CFD simulations of this study indicate that the reference design suffers temperature variations in the duct as high as 100 K. To solve this issue, the installation of mixing-enhancing structures within the outlet duct were proposed and analyzed using CFD modeling. We show that using either an optimized “Kwiat” structure (developed in this study) or a motionless mixer installed in the outlet duct, the temperature variations can be brought dramatically, with acceptable increases in pressure drop. The optimal solution appears to be to install double motionless mixers with long blades in the outlet duct, which brings the temperature variation into the acceptable range (from 100 K down to 18 K), with a resulting pressure drop increase in the HTTF loop of 0.73 kPa (6% of total pressure drop).

  1. Development of thermal mixing enhancement method for lower plenum of the High Temperature Test Facility

    International Nuclear Information System (INIS)

    Gradecka, Malwina Joanna; Woods, Brian G.

    2016-01-01

    Highlights: • Coolant mixing in lower plenum might be insufficient and pose operational issues. • Two mixing methods were developed to lower the coolant temperature variation. • The methods resulted with reduction of the temperature variation by 60% and 71%. - Abstract: The High Temperature Gas-cooled Reactor (HTGR) is one of the most mature Gen IV reactor concepts under development today. The High Temperature Test Facility (HTTF) at Oregon State University is a test facility that supports the R&D needs for HTGRs. This study focuses on the issue of helium mixing after the core section in the HTTF, the results of which are generally applicable in HTGRs. In the HTTF, hot helium jets at different temperatures are supposed to uniformly mix in the lower plenum (LP) chamber. However, the level of mixing is not sufficient to reduce the peak helium temperature before the hot jet impinges the LP structure, which can cause issues with structural materials and operational issues in the heat exchanger downstream. The maximum allowable temperature variation in the outlet duct connected to the lower plenum is defined as 40 K (±20 K from the average temperature), while the CFD simulations of this study indicate that the reference design suffers temperature variations in the duct as high as 100 K. To solve this issue, the installation of mixing-enhancing structures within the outlet duct were proposed and analyzed using CFD modeling. We show that using either an optimized “Kwiat” structure (developed in this study) or a motionless mixer installed in the outlet duct, the temperature variations can be brought dramatically, with acceptable increases in pressure drop. The optimal solution appears to be to install double motionless mixers with long blades in the outlet duct, which brings the temperature variation into the acceptable range (from 100 K down to 18 K), with a resulting pressure drop increase in the HTTF loop of 0.73 kPa (6% of total pressure drop).

  2. Application of cultural algorithm to generation scheduling of hydrothermal systems

    International Nuclear Information System (INIS)

    Yuan Xiaohui; Yuan Yanbin

    2006-01-01

    The daily generation scheduling of hydrothermal power systems plays an important role in the operation of electric power systems for economics and security, which is a large scale dynamic non-linear constrained optimization problem. It is difficult to solve using traditional optimization methods. This paper proposes a new cultural algorithm to solve the optimal daily generation scheduling of hydrothermal power systems. The approach takes the water transport delay time between connected reservoirs into consideration and can conveniently deal with the complicated hydraulic coupling simultaneously. An example is used to verify the correctness and effectiveness of the proposed cultural algorithm, comparing with both the Lagrange method and the genetic algorithm method. The simulation results demonstrate that the proposed algorithm has rapid convergence speed and higher solution precision. Thus, an effective method is provided to solve the optimal daily generation scheduling of hydrothermal systems

  3. Remarkable catalytic activity of Bi{sub 2}O{sub 3}/TiO{sub 2} nanocomposites prepared by hydrothermal method for the degradation of methyl orange

    Energy Technology Data Exchange (ETDEWEB)

    Malligavathy, M. [Manonmaniam Sundaranar University, Department of Physics (India); Iyyapushpam, S. [Thanthai Hans Roever Arts and Science College, PG and Research Department of Physics (India); Nishanthi, S. T. [Central Electro Chemical Research Institute, Electrochemical Materials Division (India); Pathinettam Padiyan, D., E-mail: dppadiyan@msuniv.ac.in [Manonmaniam Sundaranar University, Department of Physics (India)

    2017-04-15

    Visible light Bi{sub 2}O{sub 3}/TiO{sub 2} nanocomposites are successfully prepared with different dosages of Bi{sub 2}O{sub 3} by hydrothermal process. All the as-prepared samples are characterized by X-ray diffraction (XRD), scanning and transmission electron microscopes (SEM and TEM), Brunauer-Emmett-Teller analysis (BET), N{sub 2} adsorption-desorption measurement, and UV-Vis diffuse reflectance spectra (DRS). XRD and Raman spectra reveal the anatase phase of both TiO{sub 2} and Bi{sub 2}O{sub 3}/TiO{sub 2} nanocomposites. X-ray diffraction patterns demonstrate that the bismuth ions did not enter into the lattice of TiO{sub 2}, and Bi{sub 2}O{sub 3} is extremely dispersive on the surface of TiO{sub 2} nanoparticles. The incorporation of Bi{sub 2}O{sub 3} in TiO{sub 2} leads to the spectral response of TiO{sub 2} in the visible light region and efficient separation of charge carriers. The enhanced visible light activity is tested by the photocatalytic degradation of methyl orange under light illumination, and the performance of Bi{sub 2}O{sub 3}/TiO{sub 2} nanocomposites are superior than that of pure TiO{sub 2} which is ascribed to the efficient charge separation and transfer across the Bi{sub 2}O{sub 3}/TiO{sub 2} junction. Bi{sub 2}O{sub 3}/TiO{sub 2} nanocomposite (20 mg) loaded with 0.25 of Bi{sub 2}O{sub 3} dispersed in 50 ml of 5 ppm methyl orange solution exhibited the highest photocatalytic activity of 98.86% within 240 min of irradiation, which is attributed to the low band gap, high surface area, and the strong interaction between Bi{sub 2}O{sub 3} and TiO{sub 2}.

  4. Effect of pH value on particle morphology and electrochemical properties of LiFePO4 by hydrothermal method

    International Nuclear Information System (INIS)

    Song, Qingzhu; Ou, Xiuqin; Wang, Li; Liang, Guangchuan; Wang, Zuorui

    2011-01-01

    Graphical abstract: The pH value of system is adjusted in the range of 2.5-8.8 by using dilute sulfuric acid and ammonia water. The results indicated that the particle exhibits acute angle diamond flake-like morphology at pH = 2.5. With increase of pH value, the particle gradually becomes to round flake-like and irregular flake-like morphology. The optimal sample synthesized at pH = 6.4 exhibits discharge capacities of 151.8 mAh g -1 at 0.2 C rate and 129.3 mAh g -1 at 3 C rate. Highlights: → The pH value of solution affects greatly on particle morphology. → The solubility product determined the transition of interphases. → The disorder of atoms in crystal is affected by pH value. → LiFePO 4 with high capacity could be synthesized at slight acid or neutral conditions. -- Abstract: Lithium iron phosphate was prepared by hydrothermal synthesis using LiOH.H 2 O, FeSO 4 .7H 2 O and H 3 PO 4 as raw materials. The effects of pH value of reaction solution on particle morphology and electrochemical property were investigated. The pH value of the reaction solution was adjusted in the range of 2.5-8.8 by dilute sulfuric acid and ammonia water. The samples were characterized by field-emission scanning electronic microscope (FE-SEM), X-ray powder diffraction (XRD), constant-current charge/discharge cycling tests and chemical analysis. The results indicated that the particles exhibited acute angle diamond flake-like morphology at pH = 2.5, and as the pH value increased, the particle became hexagon flake-like, round flake-like and irregular flake-like morphology gradually. The optimal sample synthesized at pH = 6.4 exhibited discharge capacities of 151.8 mAh g -1 at 0.2 C rate and 129.3 mAh g -1 at 3 C rate. It was found that pH value affected the morphologies and properties of the product by means of different crystal growth rates.

  5. Template-less surfactant-free hydrothermal synthesis NiO nanoflowers and their photoelectrochemical hydrogen production

    KAUST Repository

    Qurashi, Ahsanulhaq

    2015-12-01

    A facile direct surfactant-free template-less hydrothermal method is employed for the growth of high surface-area NiO nanoflowers made up of complex and assembled nanosheets network.Field emission scanning electron microscopy revealed that each nanosheet is about 50-60nm thick. Detailed structural analysis reveals single-crystalline nature of NiO nanoflowers with cubic crystal structure. The optical absorption bands in the wavelength range of 350-800nm illustrated in terms of ligand field theory. The photoelectrochemical (PEC), water splitting performance on the NiO nanoflowers were also investigated. © 2015 Hydrogen Energy Publications, LLC.

  6. Template-less surfactant-free hydrothermal synthesis NiO nanoflowers and their photoelectrochemical hydrogen production

    KAUST Repository

    Qurashi, Ahsanulhaq; Zhang, Zhongai; Asif, M.; Yamazaki, Toshinari

    2015-01-01

    A facile direct surfactant-free template-less hydrothermal method is employed for the growth of high surface-area NiO nanoflowers made up of complex and assembled nanosheets network.Field emission scanning electron microscopy revealed that each nanosheet is about 50-60nm thick. Detailed structural analysis reveals single-crystalline nature of NiO nanoflowers with cubic crystal structure. The optical absorption bands in the wavelength range of 350-800nm illustrated in terms of ligand field theory. The photoelectrochemical (PEC), water splitting performance on the NiO nanoflowers were also investigated. © 2015 Hydrogen Energy Publications, LLC.

  7. Hydrothermal synthesis of cathode materials

    Science.gov (United States)

    Chen, Jiajun; Wang, Shijun; Whittingham, M. Stanley

    A number of cathodes are being considered for the next generation of lithium ion batteries to replace the expensive LiCoO 2 presently used. Besides the layered oxides, such as LiNi yMn yCo 1-2 yO 2, a leading candidate is lithium iron phosphate with the olivine structure. Although this material is inherently low cost, a manufacturing process that produces electrochemically active LiFePO 4 at a low cost is also required. Hydrothermal reactions are one such possibility. A number of pure phosphates have been prepared using this technique, including LiFePO 4, LiMnPO 4 and LiCoPO 4; this method has also successfully produced mixed metal phosphates, such as LiFe 0.33Mn 0.33Co 0.33PO 4. Ascorbic acid was found to be better than hydrazine or sugar at preventing the formation of ferric ions in aqueous media. When conductive carbons are added to the reaction medium excellent electrochemical behavior is observed.

  8. A Facile Method to Fabricate Anisotropic Hydrogels with Perfectly Aligned Hierarchical Fibrous Structures.

    Science.gov (United States)

    Mredha, Md Tariful Islam; Guo, Yun Zhou; Nonoyama, Takayuki; Nakajima, Tasuku; Kurokawa, Takayuki; Gong, Jian Ping

    2018-03-01

    Natural structural materials (such as tendons and ligaments) are comprised of multiscale hierarchical architectures, with dimensions ranging from nano- to macroscale, which are difficult to mimic synthetically. Here a bioinspired, facile method to fabricate anisotropic hydrogels with perfectly aligned multiscale hierarchical fibrous structures similar to those of tendons and ligaments is reported. The method includes drying a diluted physical hydrogel in air by confining its length direction. During this process, sufficiently high tensile stress is built along the length direction to align the polymer chains and multiscale fibrous structures (from nano- to submicro- to microscale) are spontaneously formed in the bulk material, which are well-retained in the reswollen gel. The method is useful for relatively rigid polymers (such as alginate and cellulose), which are susceptible to mechanical signal. By controlling the drying with or without prestretching, the degree of alignment, size of superstructures, and the strength of supramolecular interactions can be tuned, which sensitively influence the strength and toughness of the hydrogels. The mechanical properties are comparable with those of natural ligaments. This study provides a general strategy for designing hydrogels with highly ordered hierarchical structures, which opens routes for the development of many functional biomimetic materials for biomedical applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Validation of the cleaning and sanitization method for radiopharmaceutical production facilities

    International Nuclear Information System (INIS)

    Robles, Anita; Morote, Mario; Moore, Mariel; Castro, Delcy; Paragulla, Wilson; Novoa, Carlos; Otero, Manuel; Miranda, Jesus; Herrera, Jorge; Gonzales, Luis

    2014-01-01

    A protocol for the cleaning and sanitization method for radiopharmaceutical production facilities has been designed and developed for the inner surface of the hot cells for the production of Sodium Pertechnetate Tc-99m and Sm-153 EDTMP, considering an extreme situation for each hot cell. Cleaning is performed with double-distilled water and sanitation with two disinfectant solutions, 70 % isopropyl alcohol and 3 % hydrogen peroxide in alternate weeks. Microbiological analysis of sanitized surfaces were made after 20 minutes and 48 hours for the hot cell of Tc-99m and 72 hours for the hot cell of EDTMP Sm-153 in 3 consecutive tests by the method of direct contact with plates containing culture medium, made for each sampling point (6 in the first and five in the second). The results showed that the microbial load on surfaces sanitized was below acceptable limits and that the lifetime of cleaning and sanitization is 48 hours for the hot cell of Tc-99m and 72 hours for the one of EDTMP-Sm-153. As a conclusion, the method of cleaning and sanitization is effective to reduce or eliminate microbial contamination therefore, the process is validated. (authors).

  10. Additional Energy Losses from Asymmetric and Non-Sinusoidal Current in an Electrical Facility and Methods of their Reduction

    Directory of Open Access Journals (Sweden)

    Tarasov Evgeniy V.

    2015-01-01

    Full Text Available Influence of the asymmetry and higher harmonics of current on the operation of an electrical facility is analyzed. The level of additional losses from the asymmetric and non-sinusoidal currents is evaluated for a 110 kV electrical network in the Siberian Region of the Russian Federation. Methods for reducing the additional energy losses in the electrical facility are suggested.

  11. Hydrothermal pretreatment of coal

    Energy Technology Data Exchange (ETDEWEB)

    Ross, D.S.

    1989-12-21

    We have examined changes in Argonne Premium samples of Wyodak coal following 30 min treatment in liquid water at autogenous pressures at 150{degrees}, 250{degrees}, and 350{degrees}C. In most runs the coal was initially dried at 60{degrees}C/1 torr/20 hr. The changes were monitored by pyrolysis field ionization mass spectrometry (py-FIMS) operating at 2.5{degrees}C/min from ambient to 500{degrees}C. We recorded the volatility patterns of the coal tars evolved over that temperature range, and in all cases the tar yields were 25%--30% of the starting coal on mass basis. There was essentially no change after the 150{degrees}C treatment. Small increases in volatility were seen following the 250{degrees}C treatment, but major effects were seen in the 350{degrees} work. The tar quantity remained unchanged; however, the volatility increased so the temperature of half volatility for the as-received coal of 400{degrees}C was reduced to 340{degrees}C. Control runs with no water showed some thermal effect, but the net effect from the presence of liquid water was clearly evident. The composition was unchanged after the 150{degrees} and 250{degrees}C treatments, but the 350{degrees} treatment brought about a 30% loss of oxygen. The change corresponded to loss of the elements of water, although loss of OH'' seemed to fit the analysis data somewhat better. The water loss takes place both in the presence and in the absence of added water, but it is noteworthy that the loss in the hydrothermal runs occurs at p(H{sub 2}O) = 160 atm. We conclude that the process must involve the dehydration solely of chemically bound elements of water, the dehydration of catechol is a specific, likely candidate.

  12. Hydrothermal synthesis of silico-manganese nanohybrid for Cu(II) adsorption from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Qiufeng, E-mail: zhuqiufeng@th.btbu.edu.cn; Wang, Liting; An, Zehuan; Ye, Hong; Feng, Xudong

    2016-05-15

    Highlights: • A novel silico-manganese nanohybrid adsorbent (SMNA) was synthesized by a hydrothermal method. • The adsorption capacities of the SMNA for Cu(II) are lower pH dependency. • As-adsorbents are very efficient at low metal concentration and substantial amounts of Cu(II) can be removed from aqueous solution. - Abstract: A novel silico-manganese nanohybrid adsorbent (SMNA) was synthesized by a facile hydrothermal method, and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption, Fourier transform infrared spectroscopy (FT-IR) and zeta potential measurement. The adsorption of Cu(II) ions from aqueous solution on the SMNA was investigated with variations in contact time, pH and initial Cu(II) concentration. The results showed that hydrothermal method would generate nanowire/nanorod incomplete crystallite (δ-MnO{sub 2}) adsorbent. The adsorption of Cu(II) onto SMNA increased sharply within 25 min and reached equilibrium gradually. The maximum adsorption capacities of SMNA for Cu(II) were ∼40–88 mg g{sup −1}, which was lower than δ-MnO{sub 2} (92.42 mg g{sup −1}) but had a lower pH dependency. As compared with δ-MnO{sub 2}, higher adsorption capacities of SMNA (7.5–15 wt% of silica doping amount) for Cu(II) could be observed when pH of the aqueous solution was low (<4). The pseudo-second-order model was the best choice to describe the adsorption behavior of Cu(II) onto SMNA, suggesting that the removal of Cu(II) by the as-prepared adsorbents was dominated by migration of Cu(II). The possibility of Cu(II) recovery was also investigated and it revealed that SMNA was a promising recyclable adsorbent for removal of heavy metal ions in water and wastewater treatment.

  13. Future carbon beams at SPIRAL1 facility: Which method is the most efficient?

    Science.gov (United States)

    Maunoury, L.; Delahaye, P.; Angot, J.; Dubois, M.; Dupuis, M.; Frigot, R.; Grinyer, J.; Jardin, P.; Leboucher, C.; Lamy, T.

    2014-02-01

    Compared to in-flight facilities, Isotope Separator On-Line ones can in principle produce significantly higher radioactive ion beam intensities. On the other hand, they have to cope with delays for the release and ionization which make the production of short-lived isotopes ion beams of reactive and refractory elements particularly difficult. Many efforts are focused on extending the capabilities of ISOL facilities to those challenging beams. In this context, the development of carbon beams is triggering interest [H. Frånberg, M. Ammann, H. W. Gäggeler, and U. Köster, Rev. Sci. Instrum. 77, 03A708 (2006); M. Kronberger, A. Gottberg, T. M. Mendonca, J. P. Ramos, C. Seiffert, P. Suominen, and T. Stora, in Proceedings of the EMIS 2012 [Nucl. Instrum. Methods Phys. Res. B Production of molecular sideband radioisotope beams at CERN-ISOLDE using a Helicon-type plasma ion source (to be published)]: despite its refractory nature, radioactive carbon beams can be produced from molecules (CO or CO2), which can subsequently be broken up and multi-ionized to the required charge state in charge breeders or ECR sources. This contribution will present results of experiments conducted at LPSC with the Phoenix charge breeder and at GANIL with the Nanogan ECR ion source for the ionization of carbon beams in the frame of the ENSAR and EMILIE projects. Carbon is to date the lightest condensable element charge bred with an ECR ion source. Charge breeding efficiencies will be compared with those obtained using Nanogan ECRIS and charge breeding times will be presented as well.

  14. Application of Hydrothermal and Non-Hydrothermal TiO2 Nanoporous Materials as New Adsorbents for Removal of Heavy Metal Ions from Aqueous System

    Directory of Open Access Journals (Sweden)

    Mansoor Anbia

    2016-06-01

    Full Text Available Hydrothermal and non-hydrothermal spherical TiO2 nanoporous with crystalline framework were prepared by sol-gel method. The Crystalline structures, morphologies and surface texturing of materials were determined by X-ray diffraction (XRD, scanning electron microscopy (SEM and N2 adsorption-desorption isotherms. The Hydrothermal spherical TiO2 nanoporous was found to have a narrow and strong pore size distribution peaks with average of 37.8 Å and pore volume of 0.41 cm3/g and the (Brunauer–Emmett–TellerBET specific surface area of 365 m2/g. Hydrothermal and non-hydrothermal spherical TiO2 nanoporous have been used as adsorbent to study of the adsorption behavior of Pb(II, Co(II and Ni(II ions from aqueous system in a batch system. Effect of equilibrium time on adsorption Pb(II, Co(II and Ni(II ions on these adsorbent was studied The results show that the shaking time 0.5 to 10h has no serious effect on the percentage of ions removal, and the adsorption is fast in all cases. The maximum uptake capacities of Hydrothermal and non-hydrothermal spherical TiO2 nanoporous was calculated. Both hydrothermal and non-hydrothermal TiO2 nanoporous materials were found to have very good potential as new adsorbents in removal of these ions. In batch systems the maximum uptake capacities of Pb(II, Ni(II and Co(II on the hydrothermal and non-hydrothermal TiO2 nanoporous materials was Co(II > Pb(II > Ni(II and Co(II > Ni(II > Pb(II, respectively.

  15. Synthesis of Nanoscale CaO-Al2O3-SiO2-H2O and Na2O-Al2O3-SiO2-H2O Using the Hydrothermal Method and Their Characterization

    Directory of Open Access Journals (Sweden)

    Jingbin Yang

    2017-06-01

    Full Text Available C-A-S-H (CaO-Al2O3-SiO2-H2O and N-A-S-H (Na2O-Al2O3-SiO2-H2O have a wide range of chemical compositions and structures and are difficult to separate from alkali-activated materials. Therefore, it is difficult to analyze their microscopic properties directly. This paper reports research on the synthesis of C-A-S-H and N-A-S-H particles with an average particle size smaller than 300 nm by applying the hydrothermal method. The composition and microstructure of the products with different CaO(Na2O/SiO2 ratios and curing conditions were characterized using XRD, the RIR method, FTIR, SEM, TEM, and laser particle size analysis. The results showed that the C-A-S-H system products with a low CaO/SiO2 ratio were mainly amorphous C-A-S-H gels. With an increase in the CaO/SiO2 ratio, an excess of Ca(OH2 was observed at room temperature, while in a high-temperature reaction system, katoite, C4AcH11, and other crystallized products were observed. The katoite content was related to the curing temperature and the content of Ca(OH2 and it tended to form at a high-temperature and high-calcium environment, and an increase in the temperature renders the C-A-S-H gels more compact. The main products of the N-A-S-H system at room temperature were amorphous N-A-S-H gels and a small amount of sodalite. An increase in the curing temperature promoted the formation of the crystalline products faujasite and zeolite-P. The crystallization products consisted of only zeolite-P in the high-temperature N-A-S-H system and its content were stable above 70%. An increase in the Na2O/SiO2 ratio resulted in more non-bridging oxygen and the TO4 was more isolated in the N-A-S-H structure. The composition and microstructure of the C-A-S-H and N-A-S-H system products synthesized by the hydrothermal method were closely related to the ratio of the raw materials and the curing conditions. The results of this study increase our understanding of the hydration products of alkali

  16. On a new method to compute photon skyshine doses around radiotherapy facilities

    Energy Technology Data Exchange (ETDEWEB)

    Falcao, R.; Facure, A. [Comissao Nacional de Eenrgia Nuclear, Rio de Janeiro (Brazil); Xavier, A. [PEN/Coppe -UFRJ, Rio de Janeiro (Brazil)

    2006-07-01

    Full text of publication follows: Nowadays, in a great number of situations constructions are raised around radiotherapy facilities. In cases where the constructions would not be in the primary x-ray beam, 'skyshine' radiation is normally accounted for. The skyshine method is commonly used to to calculate the dose contribution from scattered radiation in such circumstances, when the roof shielding is projected considering there will be no occupancy upstairs. In these cases, there will be no need to have the usual 1,5-2,0 m thick ceiling, and the construction costs can be considerably reduced. The existing expression to compute these doses do not accomplish to explain mathematically the existence of a shadow area just around the outer room walls, and its growth, as we get away from these walls. In this paper we propose a new method to compute photon skyshine doses, using geometrical considerations to find the maximum dose point. An empirical equation is derived, and its validity is tested using M.C.N.P. 5 Monte Carlo calculation to simulate radiotherapy rooms configurations. (authors)

  17. A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles

    Directory of Open Access Journals (Sweden)

    Cheng K

    2017-03-01

    Full Text Available Kuo-Wei Cheng, Shan-hui Hsu Institute of Polymer Science and Engineering, College of Engineering, National Taiwan University, Taipei, Taiwan, Republic of China Abstract: Superparamagnetic iron oxide nanoparticles (SPIO NPs have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encapsulate SPIO NPs in amphiphilic biodegradable polymer. Anionic biodegradable polyurethane nanoparticles (PU NPs with ~35 nm size and different chemistry were prepared by waterborne processes. SPIO NPs were synthesized by chemical co-precipitation. SPIO NPs were then added to the aqueous dispersion of PU NPs, followed by application of high-frequency (~20 kHz ultrasonic vibration for 3 min. This method rendered SPIO-PU hybrid NPs (size ~110 nm suspended in water. SPIO-PU hybrid NPs contained ~50–60 wt% SPIO and retained the superparamagnetic property (evaluated by a magnetometer as well as high contrast in magnetic resonance imaging. SPIO-PU NPs also showed the ability to provide cell hyperthermic treatment. Using the same ultrasonic method, hydrophobic drug (Vitamin K3 [VK3] or (9-(methylaminomethylanthracene [MAMA] could also be encapsulated in PU NPs. The VK3-PU or MAMA-PU hybrid NPs had ~35 nm size and different release profiles for PUs with different chemistry. The encapsulation efficiency for VK3 and MAMA was high (~95% without burst release. The encapsulation mechanism may be attributed to the low glass transition temperature (Tg and good mechanical compliance of PU NPs. The new encapsulation method involving waterborne biodegradable PU NPs is simple, rapid, and effective to produce multimodular NP carriers. Keywords: superparamagnetic iron oxide, polyurethane, drug release, hybrid nanoparticles

  18. Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study

    Science.gov (United States)

    Montagna, Maria Teresa; De Giglio, Osvalda; Cristina, Maria Luisa; Napoli, Christian; Pacifico, Claudia; Agodi, Antonella; Baldovin, Tatjana; Casini, Beatrice; Coniglio, Maria Anna; D’Errico, Marcello Mario; Delia, Santi Antonino; Deriu, Maria Grazia; Guida, Marco; Laganà, Pasqualina; Liguori, Giorgio; Moro, Matteo; Mura, Ida; Pennino, Francesca; Privitera, Gaetano; Romano Spica, Vincenzo; Sembeni, Silvia; Spagnolo, Anna Maria; Tardivo, Stefano; Torre, Ida; Valeriani, Federica; Albertini, Roberto; Pasquarella, Cesira

    2017-01-01

    Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis®μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis®μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis®μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis®μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations. PMID:28640202

  19. Evaluation of Legionella Air Contamination in Healthcare Facilities by Different Sampling Methods: An Italian Multicenter Study.

    Science.gov (United States)

    Montagna, Maria Teresa; De Giglio, Osvalda; Cristina, Maria Luisa; Napoli, Christian; Pacifico, Claudia; Agodi, Antonella; Baldovin, Tatjana; Casini, Beatrice; Coniglio, Maria Anna; D'Errico, Marcello Mario; Delia, Santi Antonino; Deriu, Maria Grazia; Guida, Marco; Laganà, Pasqualina; Liguori, Giorgio; Moro, Matteo; Mura, Ida; Pennino, Francesca; Privitera, Gaetano; Romano Spica, Vincenzo; Sembeni, Silvia; Spagnolo, Anna Maria; Tardivo, Stefano; Torre, Ida; Valeriani, Federica; Albertini, Roberto; Pasquarella, Cesira

    2017-06-22

    Healthcare facilities (HF) represent an at-risk environment for legionellosis transmission occurring after inhalation of contaminated aerosols. In general, the control of water is preferred to that of air because, to date, there are no standardized sampling protocols. Legionella air contamination was investigated in the bathrooms of 11 HF by active sampling (Surface Air System and Coriolis ® μ) and passive sampling using settling plates. During the 8-hour sampling, hot tap water was sampled three times. All air samples were evaluated using culture-based methods, whereas liquid samples collected using the Coriolis ® μ were also analyzed by real-time PCR. Legionella presence in the air and water was then compared by sequence-based typing (SBT) methods. Air contamination was found in four HF (36.4%) by at least one of the culturable methods. The culturable investigation by Coriolis ® μ did not yield Legionella in any enrolled HF. However, molecular investigation using Coriolis ® μ resulted in eight HF testing positive for Legionella in the air. Comparison of Legionella air and water contamination indicated that Legionella water concentration could be predictive of its presence in the air. Furthermore, a molecular study of 12 L. pneumophila strains confirmed a match between the Legionella strains from air and water samples by SBT for three out of four HF that tested positive for Legionella by at least one of the culturable methods. Overall, our study shows that Legionella air detection cannot replace water sampling because the absence of microorganisms from the air does not necessarily represent their absence from water; nevertheless, air sampling may provide useful information for risk assessment. The liquid impingement technique appears to have the greatest capacity for collecting airborne Legionella if combined with molecular investigations.

  20. A facile method to prepare superparamagnetic iron oxide and hydrophobic drug-encapsulated biodegradable polyurethane nanoparticles.

    Science.gov (United States)

    Cheng, Kuo-Wei; Hsu, Shan-Hui

    2017-01-01

    Superparamagnetic iron oxide nanoparticles (SPIO NPs) have a wide range of biomedical applications such as in magnetic resonance imaging, targeting, and hyperthermia therapy. Aggregation of SPIO NPs can occur because of the hydrophobic surface and high surface energy of SPIO NPs. Here, we developed a facile method to encapsulate SPIO NPs in amphiphilic biodegradable polymer. Anionic biodegradable polyurethane nanoparticles (PU NPs) with ~35 nm size and different chemistry were prepared by waterborne processes. SPIO NPs were synthesized by chemical co-precipitation. SPIO NPs were then added to the aqueous dispersion of PU NPs, followed by application of high-frequency (~20 kHz) ultrasonic vibration for 3 min. This method rendered SPIO-PU hybrid NPs (size ~110 nm) suspended in water. SPIO-PU hybrid NPs contained ~50-60 wt% SPIO and retained the superparamagnetic property (evaluated by a magnetometer) as well as high contrast in magnetic resonance imaging. SPIO-PU NPs also showed the ability to provide cell hyperthermic treatment. Using the same ultrasonic method, hydrophobic drug (Vitamin K3 [VK3]) or (9-(methylaminomethyl) anthracene [MAMA]) could also be encapsulated in PU NPs. The VK3-PU or MAMA-PU hybrid NPs had ~35 nm size and different release profiles for PUs with different chemistry. The encapsulation efficiency for VK3 and MAMA was high (~95%) without burst release. The encapsulation mechanism may be attributed to the low glass transition temperature (Tg) and good mechanical compliance of PU NPs. The new encapsulation method involving waterborne biodegradable PU NPs is simple, rapid, and effective to produce multimodular NP carriers.

  1. Methods for detecting and locating leaks in containment facilities using electrical potential data and electrical resistance tomographic imaging techniques

    Science.gov (United States)

    Daily, William D.; Laine, Daren L.; Laine, Edwin F.

    1997-01-01

    Methods are provided for detecting and locating leaks in liners used as barriers in the construction of landfills, surface impoundments, water reservoirs, tanks, and the like. Electrodes are placed in the ground around the periphery of the facility, in the leak detection zone located between two liners if present, and/or within the containment facility. Electrical resistivity data is collected using these electrodes. This data is used to map the electrical resistivity distribution beneath the containment liner between two liners in a double-lined facility. In an alternative embodiment, an electrode placed within the lined facility is driven to an electrical potential with respect to another electrode placed at a distance from the lined facility (mise-a-la-masse). Voltage differences are then measured between various combinations of additional electrodes placed in the soil on the periphery of the facility, the leak detection zone, or within the facility. A leak of liquid though the liner material will result in an electrical potential distribution that can be measured at the electrodes. The leak position is located by determining the coordinates of an electrical current source pole that best fits the measured potentials with the constraints of the known or assumed resistivity distribution.

  2. Quantification of methane and nitrous oxide emissions from various waste treatment facilities by tracer dilution method

    Science.gov (United States)

    Mønster, Jacob; Rella, Chris; Jacobson, Gloria; Kjeldsen, Peter; Scheutz, Charlotte

    2013-04-01

    tracer gas concentrations while another measured the nitrous oxide concentration. We present the performance of these instruments at different waste treatment facilities (waste water treatment plants, composting facilities, sludge mineralization beds, anaerobic digesters and landfills) in Denmark, and discuss the strengths and limitations of the method of the method for quantifying methane and nitrous oxide emissions from the different sources. Furthermore, we have measured the methane emissions from 10 landfills with emission rates ranging from 5 to 135 kg/h depending on the age, state, content and aftercare of the landfill. In addition, we have studied 3 waste water treatment plants, and found nitrous oxide emission of 200 to 700 g/h from the aeration tanks and a total methane emission ranging from 2 to 15 kg/h, with the primary emission coming from the sludge treatment. References Galle, B., Samuelsson, J., Svensson, B.H., and Börjesson, G. (2001). Measurements of methane emissions from landfills using a time correlation tracer method based on FTIR absorption spectroscopy. Environmental Science & Technology 35 (1), 21-25 Scheutz, C., Samuelsson, J., Fredenslund, A. M., and Kjeldsen, P. (2011). Quantification of multiple methane emission sources at landfills using a double tracer technique. Waste Management, 31(5), 1009-17 Solomon, S., D. Qin, M. Manning, R.B. Alley, T. Berntsen, N.L. Bindoff, Z. Chen, A. Chidthaisong, J.M. Gregory, G.C. Hegerl, M. Heimann, B. Hewitson, B.J. Hoskins, F. Joos, J. Jouzel, V. Kattsov, U. Lohmann, T.Matsuno, M. Molina, N. Nicholls, J.Overpeck, G. Raga, V. Ramaswamy, J. Ren, M. Rusticucci, R. Somerville, T.F. Stocker, P. Whetton, R.A.Wood and D. Wratt, 2007: Technical Summary. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

  3. Hydrothermal systems and volcano geochemistry

    Science.gov (United States)

    Fournier, R.O.

    2007-01-01

    The upward intrusion of magma from deeper to shallower levels beneath volcanoes obviously plays an important role in their surface deformation. This chapter will examine less obvious roles that hydrothermal processes might play in volcanic deformation. Emphasis will be placed on the effect that the transition from brittle to plastic behavior of rocks is likely to have on magma degassing and hydrothermal processes, and on the likely chemical variations in brine and gas compositions that occur as a result of movement of aqueous-rich fluids from plastic into brittle rock at different depths. To a great extent, the model of hydrothermal processes in sub-volcanic systems that is presented here is inferential, based in part on information obtained from deep drilling for geothermal resources, and in part on the study of ore deposits that are thought to have formed in volcanic and shallow plutonic environments.

  4. Seismic technology of nuclear fuel cycle facilities: A view of BNFL's approach and methods

    International Nuclear Information System (INIS)

    Morris, I.R.

    2001-01-01

    The approach BNFL employs in the seismic qualification of its nuclear fuel cycle facilities is described in this paper. The overall seismic qualification process from design to installation and commissioning is considered. The approach for new facilities, such as the Sellafield Mixed Oxide Fuel Plant and Windscale Vitrification Plant Line 3 currently under construction, is examined. (author)

  5. Hydrothermal growth and characterizations of dandelion-like ZnO nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kale, Rohidas B., E-mail: rb_kale@yahoo.co.in [Department of Physics, The Institute of Science, Madam Cama Road, Mumbai 400 032, (M.S.) (India); Lu, Shih-Yuan, E-mail: sylu@nthu.edu.tw [Department of Chemical Engineering, National Tsing-Hua University, Hsinchu 30013, Taiwan, ROC (China)

    2013-12-05

    Highlights: •The simple, low cost, environmental benign hydrothermal method has been used to synthesize ZnO nanostructure. •The SEM images reveal the interesting 3D dandelion-like morphology of synthesized ZnO nanostructure. The SAED pattern and HRTEM study confirms that the ZnO nanorods are single crystalline. •Change in experimental conditions dramatically changes the morphologies of the synthesized ZnO. •The room temperature PL study reveals strong band edge emission along with much weaker defect related blue emission. •The reaction and growth mechanism of ZnO nanostructure is also discussed. -- Abstract: Three dimensional (3D) ZnO nanostructures have been synthesized by using a facile low-cost hydrothermal method under mild conditions. Aqueous alkaline ammonia solution of Zn(CH{sub 3}COO){sub 2} is used to grow 3D ZnO nanostructures. The X-ray diffraction (XRD) study reveals the well crystallized hexagonal structure of ZnO. SEM observations depict that the ZnO product grows in the form of nanorods united together to form 3D dandelion-like nanostructures. The elemental analysis using EDAX technique confirms the stoichiometry of the ZnO nanorods. The product exhibits special optical properties with red-shifts in optical absorption peak (376 nm) as compared with those of conventional ZnO nanorods. PL spectra show emission peak (396 nm) at the near band-edge and peak (464 nm) originated from defects states that are produced during the hydrothermal growth. TEM and SAED results reveal single crystalline structure of the synthesized product. The reaction and growth mechanisms on the morphological evolution of the ZnO nanostructures are discussed. The morphology of ZnO product is investigated by varying the reaction time, temperature, and type of complexing reagent.

  6. Hydrothermal synthesis of hexagonal magnesium hydroxide nanoflakes

    International Nuclear Information System (INIS)

    Wang, Qiang; Li, Chunhong; Guo, Ming; Sun, Lingna; Hu, Changwen

    2014-01-01

    Graphical abstract: Hexagonal Mg(OH) 2 nanoflakes were synthesized via hydrothermal method in the presence of PEG-20,000. Results show that PEG-20,000 plays an important role in the formation of this kind of nanostructure. The SAED patterns taken from the different positions on a single hexagonal Mg(OH) 2 nanoflake yielded different crystalline structures. The structure of the nanoflakes are polycrystalline and the probable formation mechanism of Mg(OH) 2 nanoflakes is discussed. - Highlights: • Hexagonal Mg(OH) 2 nanoflakes were synthesized via hydrothermal method. • PEG-20,000 plays an important role in the formation of hexagonal nanostructure. • Mg(OH) 2 nanoflakes show different crystalline structures at different positions. • The probable formation mechanism of hexagonal Mg(OH) 2 nanoflakes was reported. - Abstract: Hexagonal magnesium hydroxide (Mg(OH) 2 ) nanoflakes were successfully synthesized via hydrothermal method in the presence of the surfactant polyethylene glycol 20,000 (PEG-20,000). Results show that PEG-20,000 plays an important role in the formation of this kind of nanostructure. The composition, morphologies and structure of the Mg(OH) 2 nanoflakes were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The SAED patterns taken from the different positions on a single hexagonal Mg(OH) 2 nanoflake show different crystalline structures. The structure of the nanoflakes are polycrystalline and the probable formation mechanism of Mg(OH) 2 nanoflakes is discussed. Brunauer–Emmett–Teller (BET) analysis were performed to investigate the porous structure and surface area of the as-obtained nanoflakes

  7. Hydrothermal synthesis and characterization of Si and Sr co-substituted hydroxyapatite nanowires using strontium containing calcium silicate as precursors

    International Nuclear Information System (INIS)

    Zhang, Na; Zhai, Dong; Chen, Lei; Zou, Zhaoyong; Lin, Kaili; Chang, Jiang

    2014-01-01

    In the absence of any organic surfactants and solvents, the silicon (Si) and strontium (Sr) co-substituted hydroxyapatite [Ca 10 (PO 4 ) 6 (OH) 2 , Si/Sr-HAp] nanowires were synthesized via hydrothermal treatment of the Sr-containing calcium silicate (Sr-CS) powders as the precursors in trisodium phosphate (Na 3 PO 4 ) aqueous solution. The morphology, phase, chemical compositions, lattice constants and the degradability of the products were characterized. The Si/Sr-HAp nanowires with diameter of about 60 nm and up to 2 μm in length were obtained after hydrothermal treatment of the Sr-CS precursors. The Sr and Si substitution amount of the HAp nanowires could be well regulated by facile tailoring the Sr substitution level of the precursors and the reaction ratio of the precursor/solution, respectively. The SiO 4 tetrahedra and Sr 2+ ions occupied the crystal sites of the HAp, and the lattice constants increased apparently with the increase of the substitution amount. EDS mapping also suggested the uniform distribution of Si and Sr in the synthetic nanowires. Moreover, the Si/Sr-substitution apparently improved the degradability of the HAp materials. Our study suggested that the precursor transformation method provided a facile approach to synthesize the Si/Sr co-substituted HAp nanowires with controllable substitution amount, and the synthetic Si/Sr-HAp nanowires might be used as bioactive materials for hard tissue regeneration applications. - Highlights: • Si/Sr-HAp nanowires were hydrothermally transformed from Sr x -CaSiO 3 precursors. • The Si/Sr-substitution level could be facilely regulated. • The nanowire-like morphology and composition could be simultaneously regulated

  8. DEFENSE WASTE PROCESSING FACILITY ANALYTICAL METHOD VERIFICATION FOR THE SLUDGE BATCH 5 QUALIFICATION SAMPLE

    International Nuclear Information System (INIS)

    Click, D; Tommy Edwards, T; Henry Ajo, H

    2008-01-01

    For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) performs confirmation of the applicability of the digestion method to be used by the DWPF lab for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) receipt samples and SRAT product process control samples. DWPF SRAT samples are typically dissolved using a room temperature HF-HNO3 acid dissolution (i.e., DWPF Cold Chem Method, see Procedure SW4-15.201) and then analyzed by inductively coupled plasma - atomic emission spectroscopy (ICP-AES). This report contains the results and comparison of data generated from performing the Aqua Regia (AR), Sodium Peroxide/Hydroxide Fusion (PF) and DWPF Cold Chem (CC) method digestion of Sludge Batch 5 (SB5) SRAT Receipt and SB5 SRAT Product samples. The SB5 SRAT Receipt and SB5 SRAT Product samples were prepared in the SRNL Shielded Cells, and the SRAT Receipt material is representative of the sludge that constitutes the SB5 Batch composition. This is the sludge in Tank 51 that is to be transferred into Tank 40, which will contain the heel of Sludge Batch 4 (SB4), to form the SB5 Blend composition. The results for any one particular element should not be used in any way to identify the form or speciation of a particular element in the sludge or used to estimate ratios of compounds in the sludge. A statistical comparison of the data validates the use of the DWPF CC method for SB5 Batch composition. However, the difficulty that was encountered in using the CC method for SB4 brings into question the adequacy of CC for the SB5 Blend. Also, it should be noted that visible solids remained in the final diluted solutions of all samples digested by this method at SRNL (8 samples total), which is typical for the DWPF CC method but not seen in the other methods. Recommendations to the DWPF for application to SB5 based on studies to date: (1) A dissolution study should be performed on the WAPS

  9. A Facile Method for Preparing Transparent, Conductive, and Paper-Like Silver Nanowire Films

    Directory of Open Access Journals (Sweden)

    Yajie Wang

    2011-01-01

    Full Text Available Transparent, conductive, and flexible silver nanowire (AgNW films have been fabricated by a facile two-step method. Firstly, the well-dispersed AgNW suspension is vacuum filtered using mixed esters of cellulose (MCE membranes as filters. Then, the AgNW-MCE films are treated with acetone vapor. After the infiltration of acetone vapor, the white and porous MCE membranes change into transparent and pore-free, and AgNW-MCE films are obtained with extraordinary optical, conductive, and mechanical properties. An optimal result is obtained with transmittance of 85% at 550 nm and sheet resistance about 50 Ohm/sq. The flexibility of AgNW-MCE films is remarkable, which is comparable to that of the AgNW film on flexible polyethylene terephthalate (PET. More important, AgNW-MCE films show an excellent adhesion to the substrate, which causes a stable electrical conductivity even after scotch tape test and finger friction test. As a result of improved adhesion to the substrate, the sheet resistance of AgNW-MCE films is about 20% smaller than that of AgNW-PET films.

  10. Size-controlled fluorescent nanodiamonds: A facile method of fabrication and color-center counting

    KAUST Repository

    Mahfouz, Remi

    2013-01-01

    We present a facile method for the production of fluorescent diamond nanocrystals (DNCs) of different sizes and efficiently quantify the concentration of emitting defect color centers (DCCs) of each DNC size. We prepared the DNCs by ball-milling commercially available micrometer-sized synthetic (high pressure, high temperature (HPHT)) diamonds and then separated the as-produced DNCs by density gradient ultracentrifugation (DGU) into size-controlled fractions. A protocol to enhance the uniformity of the nitrogen-vacancy (NV) centers in the diamonds was devised by depositing the DNCs as a dense monolayer on amino-silanized silicon substrates and then subjecting the monolayer to He+ beam irradiation. Using a standard confocal setup, we analyzed the average number of NV centers per crystal, and obtained a quantitative relationship between the DNC particle size and the NV number per crystal. This relationship was in good agreement with results from previous studies that used more elaborate setups. Our findings suggest that nanocrystal size separation by DGU may be used to control the number of defects per nanocrystal. The efficient approaches described herein to control and quantify DCCs are valuable to researchers as they explore applications for color centers and new strategies to create them. © 2013 The Royal Society of Chemistry.

  11. Selection of facility location under environmental damage priority and using ELECTRE method.

    Science.gov (United States)

    Gundogdu, Ceren Erdin

    2011-03-01

    In the recent years, the environmental problems have reached to a vital extent, which is pushing the boundaries and far beyond daily evaluations. Industrial plants, the energy sources and uncontrolled release of pollutant gases (SO2, CO2 etc.) in the production stage have the greatest share in the occurrence of unfavorable environmental conditions. For this reason, the dimension of the problems that may arise in the production stage of industrial plants is directly related to the selection of facility location. In this study, geographical regions (a total of 7 regions) of our country have been analyzed in terms of environmental values based on their basins and the unfavorable environmental problems that are currently being experienced. Considered as such, with the directives of an expert group composed of nature scientists, the criteria and alternative areas are determined using the data gathered on ecosystem, basin characteristics, and land types. Since the primary goal is to keep the environmental damages at the minimum level, comprehensive definition of the problem is constructed by consultation of the expert group and the criteria are determined. Considering the fact that it will prevent the drawbacks generated by making decisions depending on certain stereotypes toa great extent, ELECTRE (Elimination and Choice Translating Reality English - Elimination Et Choix Traduisant la Realite) method is used to determine in which geographic region our country's industrial plants should be located.

  12. A facile method for preparation superhydrophobic paper with enhanced physical strength and moisture-proofing property.

    Science.gov (United States)

    Li, Hui; Yang, Jin; Li, Pan; Lan, Tianqing; Peng, Lincai

    2017-03-15

    We proposed a green and facile method to fabricate superhydrophobic paper in this study, which is layer-by-layer (LBL) deposition of TiO 2 nanoparticles/sodium alginate (ALG) multilayers on paper surface followed by an adsorption treatment of colloidal carnauba wax. The formation of TiO 2 /ALG multilayers on paper surface was characterized by X-ray photoelectron spectroscopy (XPS), zeta potential measurement, scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The wetting property of modified paper was investigated by water contact angle (WCA) measurement. Moreover, the modified paper tensile strength has been evaluated. The results showed that WCA of paper modified with a wax-treated (TiO 2 /ALG) 3.5 multilayer reached up to 151.5°, and this obtained superhydrophobic paper exhibited improved tensile strength (increased by 4.1% compared to the pristine paper), excellent moisture-proofing property and high strength stability under high relative humidity condition, which might has a great potential for use in the liquid paper packaging and moisture-proof paper packaging. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. A facile method to compare EFTEM maps obtained from materials changing composition over time

    KAUST Repository

    Casu, Alberto

    2015-10-31

    Energy Filtered Transmission Electron Microscopy (EFTEM) is an analytical tool that has been successfully and widely employed in the last two decades for obtaining fast elemental maps in TEM mode. Several studies and efforts have been addressed to investigate limitations and advantages of such technique, as well as to improve the spatial resolution of compositional maps. Usually, EFTEM maps undergo post-acquisition treatments by changing brightness and contrast levels, either via dedicated software or via human elaboration, in order to maximize their signal-to-noise ratio and render them as visible as possible. However, elemental maps forming a single set of EFTEM images are usually subjected to independent map-by-map image treatment. This post-acquisition step becomes crucial when analyzing materials that change composition over time as a consequence of an external stimulus, because the map-by-map approach doesn\\'t take into account how the chemical features of the imaged materials actually progress, in particular when the investigated elements exhibit very low signals. In this article, we present a facile procedure applicable to whole sets of EFTEM maps acquired on a sample that is evolving over time. The main aim is to find a common method to treat the images features, in order to make them as comparable as possible without affecting the information there contained. Microsc. Res. Tech. 78:1090–1097, 2015. © 2015 Wiley Periodicals, Inc.

  14. Analysis format and evaluation methods for effluent particle sampling systems in nuclear facilities

    International Nuclear Information System (INIS)

    Schwendiman, L.C.; Glissmeyer, J.A.

    1976-06-01

    Airborne effluent sampling systems for nuclear facilities are frequently designed, installed, and operated without a systematic approach which discloses and takes into account all the circumstances and conditions which would affect the validity and adequacy of the sample. Without a comprehensive check list or something similar, the designer of the system may not be given the important information needed to provide a good design. In like manner, an already operating system may be better appraised. Furthermore, the discipline of a more formal approach may compel the one who will use the system to make sure he knows what he wants and can thus give the designer the needed information. An important consideration is the criteria to be applied to the samples to be taken. This analysis format consists of a listing of questions and statements calling forth the necessary information required to analyze a sampling system. With this information developed, one can proceed with an evaluation, the methodology of which is also discussed in the paper. Errors in probe placement, failure to sample at the proper rate, delivery line losses, and others are evaluated using mathematical models and empirically derived relationships. Experimental methods are also described for demonstrating that quality sampling will be achieved. The experiments include using a temporary, simple, but optimal sample collection system to evaluate the more complex systems. The use of tracer particles injected in the stream is also discussed. The samples obtained with the existing system are compared with those obtained by the temporary, optimal system

  15. Fault detection and analysis in nuclear research facility using artificial intelligence methods

    Energy Technology Data Exchange (ETDEWEB)

    Ghazali, Abu Bakar, E-mail: Abakar@uniten.edu.my [Department of Electronics & Communication, College of Engineering, Universiti Tenaga Nasional, 43009 Kajang, Selangor (Malaysia); Ibrahim, Maslina Mohd [Instrumentation Program, Malaysian Nuclear Agency, Bangi (Malaysia)

    2016-01-22

    In this article, an online detection of transducer and actuator condition is discussed. A case study is on the reading of area radiation monitor (ARM) installed at the chimney of PUSPATI TRIGA nuclear reactor building, located at Bangi, Malaysia. There are at least five categories of abnormal ARM reading that could happen during the transducer failure, namely either the reading becomes very high, or very low/ zero, or with high fluctuation and noise. Moreover, the reading may be significantly higher or significantly lower as compared to the normal reading. An artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) are good methods for modeling this plant dynamics. The failure of equipment is based on ARM reading so it is then to compare with the estimated ARM data from ANN/ ANFIS function. The failure categories in either ‘yes’ or ‘no’ state are obtained from a comparison between the actual online data and the estimated output from ANN/ ANFIS function. It is found that this system design can correctly report the condition of ARM equipment in a simulated environment and later be implemented for online monitoring. This approach can also be extended to other transducers, such as the temperature profile of reactor core and also to include other critical actuator conditions such as the valves and pumps in the reactor facility provided that the failure symptoms are clearly defined.

  16. Degradation diagnosing method for low voltage electric wire and cable in nuclear facility

    International Nuclear Information System (INIS)

    Kamimura, Seiji; Seki, Ikuo; Yagyu, Hideki; Onishi, Takao; Kusama, Yasuo.

    1991-01-01

    A considerable skill is required for a visual inspection method which has been used most widely for determining the degradation of low voltage electric wires and cables used mostly in facilities such as nuclear power plants. It is extremely difficult to determine the degradation accurately and appropriately even for skilled inspectors because of individual difference. Then, a small amount of organic insulation materials is taken as a sample from insulators or sheath materials actually disposed. The pyrolytic temperature of the sample is measured by thermal gravimetric analysis to determine the extent of the degradation of the electric wire and cable based on the relationship between the degradation and the elongation. Since there is a close relationship between the temperature at which the measured weight of the sample is reduced by 5% and the degradation behavior of the mechanical property, analysis can be conducted effectively by an extremely small amount of the sample. Since the insulation degradation of relatively low voltage electric wires and cables can be determined in a non-destructive manner at high accuracy, the lifetime can be forecasted. (N.H.)

  17. 237 Np analytical method using 239 Np tracers and application to a contaminated nuclear disposal facility

    Energy Technology Data Exchange (ETDEWEB)

    Snow, Mathew S.; Morrison, Samuel S.; Clark, Sue B.; Olson, John E.; Watrous, Matthew G.

    2017-06-01

    Environmental 237Np analyses are challenged by low 237Np concentrations and lack of an available yield tracer; we report a rapid, inexpensive 237Np analytical approach employing the short lived 239Np (t1/2 = 2.3 days) as a chemical yield tracer followed by 237Np quantification using inductively coupled plasma-mass spectrometry. 239Np tracer is obtained via separation from a 243Am stock solution and standardized using gamma spectrometry immediately prior to sample processing. Rapid digestions using a commercial, 900 watt “Walmart” microwave and Parr microwave vessels result in 99.8 ± 0.1% digestion yields, while chromatographic separations enable Np/U separation factors on the order of 106 and total Np yields of 95 ± 4% (2σ). Application of this method to legacy soil samples surrounding a radioactive disposal facility (the Subsurface Disposal Area at Idaho National Laboratory) reveal the presence of low level 237Np contamination within 600 meters of this site, with maximum 237Np concentrations on the order of 103 times greater than nuclear weapons testing fallout levels.

  18. Preparing hydrophobic nanocellulose-silica film by a facile one-pot method.

    Science.gov (United States)

    Le, Duy; Kongparakul, Suwadee; Samart, Chanatip; Phanthong, Patchiya; Karnjanakom, Surachai; Abudula, Abuliti; Guan, Guoqing

    2016-11-20

    Hydrophobic nanocellulose-silica film was successfully prepared by a facile one-pot method using tetraethoxysilane (TEOS) and dodecyl triethoxylsilane (DTES). Morphological characterization of the hydrophobic nanocellulose-silica (NC-SiO2-DTES) film showed well self-assembled DTES modified silica spherical nanoparticles with the particle sizes in the range of 88-126nm over the nanocellulose film. The hydrophobicity of the NC-SiO2-DTES film was achieved owing to the improvement of roughness of the nanocellulose film by coating dodecyl- terminated silica nanoparticles. An increase in DTES loading amount and reaction time increased the hydrophobicity of the film, and the optimum condition for NC-SiO2-DTES film preparation was achieved at DTES/TEOS molar ratio of 2.0 for 8h reaction time. Besides, the NC-SiO2-DTES film performed superoleophilic property with octane and hexadecane contact angles of 0°. It also showed an excellent hydrophobic property over all pH values ranged from 1 to 14. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. TEMPERATURE PREDICTION IN 3013 CONTAINERS IN K AREA MATERIAL STORAGE (KAMS) FACILITY USING REGRESSION METHODS

    International Nuclear Information System (INIS)

    Gupta, N

    2008-01-01

    3013 containers are designed in accordance with the DOE-STD-3013-2004. These containers are qualified to store plutonium (Pu) bearing materials such as PuO2 for 50 years. DOT shipping packages such as the 9975 are used to store the 3013 containers in the K-Area Material Storage (KAMS) facility at Savannah River Site (SRS). DOE-STD-3013-2004 requires that a comprehensive surveillance program be set up to ensure that the 3013 container design parameters are not violated during the long term storage. To ensure structural integrity of the 3013 containers, thermal analyses using finite element models were performed to predict the contents and component temperatures for different but well defined parameters such as storage ambient temperature, PuO 2 density, fill heights, weights, and thermal loading. Interpolation is normally used to calculate