scholarly journals Synthesis of Zirconia Nanoparticles and Their Ameliorative Roles as Additives Concrete Structures

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Masoud Negahdary ◽  
Amir Habibi-Tamijani ◽  
Asadollah Asadi ◽  
Saeid Ayati

We investigated synthesis of zirconia nanoparticles (Nps) and their ameliorative roles as additives concrete structures. Synthesized Zirconia Nps were studied with X-ray diffraction (XRD), UV-visible spectrophotometer, and transmission electron microscope (TEM). We used standard Portland cement in related experiment Concrete Structures. The experimental or E series (E1–E4) mixtures were prepared with different amounts of ZrO2Nps with an average particle size of 20 nm. The experimental mixtures were prepared 0.125, 0.25, 0.5 and 2.0% ZrO2Nps/cement by weight. The modified cement with ZrO2nanoparticles was studied with split tensile strength, flexural strength and setting time methods. Final results showed that Zirconia Nps could be used for their Ameliorative roles as Additives Concrete Structures.

2014 ◽  
Vol 900 ◽  
pp. 187-190
Author(s):  
Zong Hu Xiao ◽  
Wei Zhong ◽  
Kang Ping Xu ◽  
Yong Huang ◽  
Shui Gen Li ◽  
...  

Terbium-doped zinc oxide (ZnO:Tb) nanocrystals were prepared by a direct reactive precipitation progress. Incorporation of terbium in ZnO nanocrystals had been proved by X-ray diffraction (XRD), transmission electron microscope (TEM) and fluorescence spectrophotometer. XRD investigations confirm that the samples of ZnO:Tb nanocrystals with a hexagonal wurtzite crystalline structure don’t exist the diffraction peaks of the compounds of terbium. The results of TEM analysis show that the as-prepared samples with an average particle size less than 20 nm were obtained. The photoluminescence (PL) spectra suggest that there is no luminescence peaks corresponding to the terbium compounds in ZnO:Tb samples; the green emission intensity gradually decreases with the increase of the Tb-doped concentration in ZnO matrix. A core-shell model of rare earth (RE) passivated ZnO is proposed, which the passivation layer existing on the ZnO surface, can generate a barrier to impede the formation of oxygen vacancy, corresponding to the green emission.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Malathi Sampath ◽  
Ramya Vijayan ◽  
Ezhilarasu Tamilarasu ◽  
Abiraman Tamilselvan ◽  
Balasubramanian Sengottuvelan

Novel jasmine bud-shaped copper nanoparticles were synthesized by a green chemical reduction method using polyvinylpyrrolidone (PVP) as a capping agent, L-ascorbic acid (AA) as a reducing agent as well as antioxidant agent, isonicotinic acid hydrazide (INH) as a reducing agent, and water as a solvent at 60–70°C (pH-7) in the presence of air. The UV-Vis absorption maximum obtained is 573 nm. The crystal lattice (fcc) structure of Cu Nps was confirmed by X-ray diffraction (XRD). The novel jasmine bud shape was visualized in a transmission electron microscope (TEM). The height of single copper nanobud was 6.41 nm as measured by atomic force microscope (AFM). The average particle size 6.95 nm is obtained by XRD results. Antibacterial activity of the Cu nanobuds was evaluated by testing against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria.


2000 ◽  
Vol 15 (11) ◽  
pp. 2273-2275 ◽  
Author(s):  
R. N. Das ◽  
J. C. Ray ◽  
P. Pramanik

Nanocrystalline (20 nm) lead magnesium niobate (PMN) powders were prepared via a chemical process. This process involved the addition of aqueous niobium tartrate, lead-ethylenediaminetetraacetic acid, and magnesium-polyvinyl alcohol complex to produce a homogeneous solution. After the complete evaporation of the resulting homogeneous solution, the complexes decomposed and produced a black, fluffy precursor material. The precursor material on calcination up to 850 °C/2 h produced nanocrystalline PMN powders with the corresponding average particle size 20 nm. PMN powders modified with lead iron niobate (PFN) (1 – x)PMN–xPFN (x = 0.1, 0.2, and 1) were also prepared using this route and investigated through x-ray diffraction studies.


2012 ◽  
Vol 02 (01) ◽  
pp. 1250007 ◽  
Author(s):  
LAXMAN SINGH ◽  
U. S. RAI ◽  
K. D. MANDAL ◽  
MADHU YASHPAL

Ultrafine powder of CaCu2.80Zn0.20Ti4O12 ceramic was prepared using a novel semi-wet method. DTA/TG analysis of dry powder gives pre-information about formation of final product around 800°C. The formation of single phase was confirmed by X-ray diffraction analysis. The average particle size of sintered powder of the ceramic obtained from XRD and Transmission electron microscopy was found 59 nm and 102 nm, respectively. Energy Dispersive X-ray studies confirm the stoichiometry of the synthesized ceramic. Dielectric constant of the ceramic was found to be 2617 at room temperature at 1 kHz.


2016 ◽  
Vol 30 (18) ◽  
pp. 1650247 ◽  
Author(s):  
Mahdi Ghasemifard ◽  
Misagh Ghamari ◽  
Meysam Iziy

TiO2-(Ti[Formula: see text]Si[Formula: see text]O2 nanopowders (TS-NPs) with average particle size around 90 nm were successfully synthesized by controlled auto-combustion method by using citric acid/nitric acid (AC:NA) and urea/metal cation (U:MC). The structure of powders was studied based on their X-ray diffraction (XRD) patterns. The XRD of TS-NPs shows that rutile and anatase are the main phases of TS-NPs for AC:NA and U:MC, respectively. Particle size and histogram of nanopowders were characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). Optical properties of TS-NPs were calculated by Fourier transform infrared spectroscopy (FTIR) and Kramers–Kroning (KK) relation. Plasma frequencies of TS-NPs obtained from energy loss functions depend on fuels as a result of changes in crystal structure, particle size distribution, and morphology.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Branka Babić-Stojić ◽  
Vukoman Jokanović ◽  
Dušan Milivojević ◽  
Zvonko Jagličić ◽  
Darko Makovec ◽  
...  

We present a study of magnetic and structural properties of CoFe2O4nanoparticles suspended in an organic liquid. Transmission electron microscopy shows that the nanoparticles have a narrow size distribution of average particle size 5.9 ± 1.0 nm. X-ray diffraction shows that the particles are of cubic spinel crystal structure. Dynamic light scattering measurements reveal the existence of an organic shell around the CoFe2O4nanoparticles with an average hydrodynamic diameter of 14.4 nm. Coercive magnetic field atT=5 K is found to be 11.8 kOe. Disappearance of the coercive field and remanent magnetization at about 170 K suggests that the CoFe2O4nanoparticles are superparamagnetic at higher temperatures which is confirmed by the room temperature Mössbauer spectrum analysis. Saturation magnetization of the nanoparticles of 80.8 emu/g(CoFe2O4) at 5 K reaches the value detected in the bulk material and remains very high also at room temperature. The cobalt ferrite nanoparticle system synthesized in this work exhibits magnetic properties which are very suitable for various biomedical applications.


2016 ◽  
Vol 17 (1) ◽  
pp. 1-3 ◽  
Author(s):  
Sujan Dhungana ◽  
Bhoj Raj Paudel ◽  
Surendra K. Gautam

In this work, we report the ZnTe semiconductor nanoparticles (NPs) prepared by aqueous chemical precipitation method using the tellurium precursor solution with different zinc compounds. Three batches of ZnTe NPs were synthesized to study the effect of dilution on the size and phase purity of ZnTe. The influence of source compounds and concentrations of the size and structure of NPs were studied. ZnTe NPs have great applications as field-effect transistors and photodetectors. The existing controversy regarding the crystalline structure of ZnTe NPs, whether it is cubic or hexagonal, has been resolved using X-ray Diffraction (XRD) data. The ZnTe NPs possess cubic structure, which is also confirmed by Electron Diffraction (ED) pattern. The average particle size determined from XRD data with the help of Debye-Scherrer equation is about 6 nm. The particle size can be further verified by Transmission Electron Microscopy (TEM) studies.  


2011 ◽  
Vol 228-229 ◽  
pp. 639-644 ◽  
Author(s):  
Jian Lin Xu ◽  
Shu Hua Yang ◽  
Li Hui Zhang ◽  
Zhao Kang ◽  
Qiang Guo

The nano-antimony particles with different shape, size and stability are prepared by electrochemical method under the dilute hydrochloric acid electrolyte including the surface dispersant OP-10 and different current densities. The influences of current density on the shape and size of nanometer antimony particles prepared by electrochemical method are analyzed by using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FT-IR). The results show that nano-antimony powder can be prepared by electrochemical method, and the antimony powder possesses the crystal structure with orthorhombic hexahedron. The current density has a significant impact on the agglomeration, shape and size of antimony powder. The size and shape of antimony powder are determined by the nucleation rate of nano-antimony and combination capacity of antimony ions and OP-10 surface dispersing agents affected by current density. When the current density is 25mA/cm2, the average particle size is 12nm or so, the shape is spherical, and the nano-antimony particles are well dispersed and no agglomeration.


2012 ◽  
Vol 584 ◽  
pp. 219-223
Author(s):  
S.G. Gaurkhede ◽  
M.M. Khandpekar ◽  
S.P. Pati ◽  
A.T. Singh

Hexagonal-phase LaF3: Ce3+, Pr3+, and Sm3+ doped (LCPS) nano-crystals have been synthesized by keeping same molarities of rare earth elements using aqueous route. The samples have been synthesized in conventional microwave on low power range in about an hour’s time. The phase formation has been verified by powder X-ray diffraction (XRD).Hexagonal geometry of the LCPS nano-crystals has been observed with an average particle size of 20 nm by TEM analysis. The JCPDS Card No. (32-0483) and selected area electron diffraction (SAED) pattern has been used for identification of crystal structure. The UV- VIS spectra indicated band gap of 5.00eV. The FTIR spectrums have been used for assignment of fundamental vibrations. Blue fluorescence observed with exciting wavelengths of 254 nm respectively. The presence of rare-earth elements in LCPS nano-crystals have been verified by the EDAX spectra.


2008 ◽  
Vol 8 (8) ◽  
pp. 4068-4072 ◽  
Author(s):  
P. B. Patil ◽  
S. Rout ◽  
A. R. B. Rao ◽  
M. Senthil Kumar

Structural and magnetotransport properties of metallic FexAgyAlz nanogranular thin films were studied. These films with several compositions were prepared by dc magnetron sputtering. X-ray diffraction (XRD) measurements carried out on the samples show only Ag(111) peaks. The d-spacings determined from the Ag(111) peaks are smaller than the standard value for bulk Ag indicating a partial substitution of Fe and Al atoms in Ag matrix. Transmission electron diffraction (TEM) patterns show a number of Ag rings. Both XRD and TEM studies did not reveal any diffraction peaks due to Fe or Al. The average particle size determined from the TEM micrograph is 5.9 nm. This value is in good agreement with the grain size determined from the XRD patterns for the Al substituted samples. The MR was found to increase for smaller Al concentration and it decreases with further increase in Al content. In the samples investigated magnetoresistance ratio reaches a maximum value of about 4.5% for the Fe27 Ag63Al10 film.


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