INFLUENCE OF CALCINED NANOCLAY ON FRACTURE TOUGHNESS OF NAOH-TREATED HEMP FABRIC REINFORCED CEMENT NANOCOMPOSITES

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Hakamy ◽  
F. U. A. Shaikh ◽  
I. M. Low
Keyword(s):  
Fracture Toughness ◽  
Cost Benefit Analysis ◽  
Microstructural Analysis ◽  
Cost Benefit ◽  
Pozzolanic Reaction ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Reinforced Cement ◽  
Hemp Fabric

influence of calcined nanoclay (CNC) on the porosity and fracture toughness of treated hemp fabric-reinforced cement nanocomposites is presented in this paper. Characterisation of microstructure is investigated using Quantitative X-ray Diffraction Analysis (QXDA) and High Resolution Transmission Electron Microscopy (HRTEM). An optimum replacement of ordinary Portland cement with 1 wt% CNC is observed through reduced porosity and increased fracture toughness of treated hemp fabric-reinforced nanocomposite. The microstructural analysis indicates that the CNC affect not only as a filler to improve the microstructure, but also as the activator to support the pozzolanic reaction and thus improved the adhesion between the treated hemp fabric and the matrix. Cost-benefit analysis indicates the benefit of such cement eco-nanocomposites to develop new environmentally friendly nanomaterials and it can be used for various construction applications such as, ceilings and roofs.

Study on Microstructure and Fracture Toughness of TaC Ceramic Coating on HT300

2015 ◽  
Vol 1120-1121 ◽  
pp. 740-744
Author(s):  
Jie Fang Wang ◽  
Tian Tian Shao ◽  
Xiao Long Cai ◽  
Li Sheng Zhong ◽  
Na Na Zhao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Ceramic Coating ◽  
Tantalum Carbide ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Indentation Crack ◽  
The Matrix ◽  
Grey Cast ◽  
Nanoindentation Hardness ◽  
Crack Paths

Tantalum carbide (TaC) ceramic coating was produced on grey cast iron by the combined process of casting and heat treatment. The microstructure, micro-hardness, and fracture toughness of the TaC ceramic coating were investigated by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and indentation technique. The results show that TaC ceramic coating can be divided into two apparent regions, and the density of products gradually decrease from the surface to the matrix. The main phases of the ceramic coating are only TaC, α-Fe, and Fe3C. TEM examination revealed a nanostructure ceramic, in which 200~300 nm TaC grains are cemented by iron binder. The nanoindentation hardness of TaC ceramic coating vary in the range of 14~21 GPa. A close examination of the indentation crack paths of TaC samples revealed that the TaC ceramic coating have extensive crack deflection with a great amount of intergranular fracture.

Organoclay-reinforced polyethersulfone-modified epoxy-based hybrid nanocomposites

2011 ◽  
Vol 23 (7) ◽  
pp. 526-534 ◽  
Author(s):  
Yang Wang ◽  
Boming Zhang ◽  
Jinrui Ye
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Electron Microscope ◽  
Optical Microscope ◽  
Mechanical Analysis ◽  
Hybrid Nanocomposites ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Modified Epoxy ◽  
Scanning Electron

Hybrid nanocomposites were successfully prepared by the incorporation of polyethersulfone (PES) and organoclay into epoxy resin. They had higher fracture toughness than the prepared PES/epoxy blend and organoclay/epoxy nanocomposites. The microstructures of the hybrid nanocomposites were studied. They were comprised of homogeneous PES/epoxy semi-interpenetrating network (semi-IPN) matrices and organoclay micro-agglomerates made up of tactoid-like regions composed of ordered exfoliated organoclay with various orientations. The former was confirmed with dynamic mechanical analysis, scanning electron microscopy and transmission electron microscopy, while the latter was successfully observed with X-ray diffraction measurements, optical microscope, scanning electron microscope and transmission electron microscope. The improvement of their fracture toughness was due to the synergistic toughening effect of the PES and the organoclay and related to their microstructures.

Characterization of Layered Double Hydroxide Modified with Sodium Dodecyl Sulfate and its Dispersion in Polyethylene

2013 ◽  
Vol 591 ◽  
pp. 138-141
Author(s):  
Zhi Dong Han ◽  
Xin Ke Zhang ◽  
Yue Wang ◽  
Zheng Quan Jiang ◽  
Peng Wang
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Layered Double Hydroxide ◽  
Sodium Dodecyl ◽  
Melt Blending ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Dodecyl Sulfate ◽  
The Matrix ◽  
Mixing Method ◽  
Double Hydroxide

Mg-Al layered double hydroxide (LDH) was modified with sodium dodecyl sulfate (SDS) by regeneration method. The structure of modified LDH (SDS-LDH) was investigated by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The composites of SDS-LDH and polyethylene (PE) were prepared by melt blending and solution mixing method with maleated PE (PEgMA) as compatibilizer. The structure of the composites and the dispersion of SDS-LDH in the matrix were investigated by XRD and transmission electron microscopy (TEM), respectively. The results reveal that SDS was successfully intercalated into the interlayer space of LDH. SDS-LDH was hardly exfoliated in PE/PEgMA by melt blending. The nanocomposites of PE/(PEgMA/SDS-LDH) were successfully prepared by melt blending PE with SDS-LDH/PEgMA master-batch obtained by solution mixing. Homogeneous dispersion of SDS-LDH in the matrix was observed by TEM.

scholarly journals The sintering kinetics of shellfish porcelain reinforced by sepiolite nanofibres

2018 ◽  
Vol 5 (10) ◽  
pp. 180483 ◽  
Author(s):  
Li Tian ◽  
Lijuan Wang ◽  
Kailei Wang ◽  
Yuedan Zhang ◽  
Jinsheng Liang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Diffusion Mechanism ◽  
Linear Shrinkage ◽  
Liquid Phase Sintering ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Fibre Pullout ◽  
Sintering Behaviour

The work investigated the effect of sepiolite nanofibres on mechanical properties and sintering behaviour of shellfish porcelain. Samples of shellfish porcelain reinforced by sepiolite nanofibres were fired in an electric furnace at 1150, 1200 and 1250°C for a period of 80, 100, 120 and 140 min. Sintered samples were characterized by flexural strength, fracture toughness, scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results showed that 2 wt% sepiolite nanofibres could increase the flexural strength and fracture toughness of the porcelain bodies through the fibre pullout and the weak interface mechanisms. Sintering activation energies were determined according to the linear shrinkage results. It is found that the liquid-phase sintering mechanism of shellfish porcelain with sepiolite nanofibres is a diffusion mechanism. Porcelain without sepiolite is controlled by volume diffusion, and eventually, the grain boundary diffusion began to appear with the increase of sepiolite addition.

Sb-rich nanoinclusions in an AlGaAsSb metamaterial

MRS Advances ◽  
2019 ◽  
Vol 4 (5-6) ◽  
pp. 277-284
Author(s):  
Nikolay A. Bert ◽  
Vladimir V. Chaldyshev ◽  
Nikolay A. Cherkashin ◽  
Vladimir N. Nevedomskiy ◽  
Valery V. Preobrazhenskii ◽  
...  
Keyword(s):  
Molecular Beam ◽  
Filling Factor ◽  
Local Thermodynamic Equilibrium ◽  
Average Diameter ◽  
Formation Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Self Organized ◽  
Transmission Electron ◽  
The Matrix

ABSTRACTWe studied the microstructure of Al0.28Ga0.72As0.972Sb0.028 metamaterials containing a developed array of AsSb nanoinclusions. The AlGaAsSb films were grown by low-temperature molecular-beam epitaxy followed by high-temperature annealing at 750°C. The process resulted in an array of self-organized AsSb nanonclusions with an average diameter of 15 nm. The volume filling factor was about 0.003. Using transmission electron microscopy and x-ray diffraction we showed that the nanoinclusions have A7-type rhombohedral atomic structure with the following orientation in the matrix (0003)p || {111}m and [-2110]p || 〈220〉m, where p and m indices indicate the AsSb precipitate and AlGaAsSb matrix, correspondingly. The nanoinclusions appeared to be strongly enriched by antimony (more than 90 atomic %), whereas the Sb content in the AlGaAsSb matrix was 2.8 atomic %. The strong enrichment of the inclusion with Sb resulted from the local thermodynamic equilibrium between the solid AlGaAsSb matrix and AsSb inclusions which became liquid at a formation temperature of 750°C.

Temporal Evolution of Bimodal Distribution of γ’ Precipitates in Ni-Al-Mo Alloys under the Influence of Coherency Strains

1995 ◽  
Vol 398 ◽  
Author(s):  
A.D. Sequeira ◽  
H.A. Calderon ◽  
G. Kostorz
Keyword(s):  
Lattice Mismatch ◽  
Bimodal Distribution ◽  
X Ray Diffraction ◽  
Double Step ◽  
Bimodal Size Distribution ◽  
Elastic Fields ◽  
Transmission Electron ◽  
The Matrix ◽  
Kinetics Of ◽  
Coherency Strains

ABSTRACTThe influence of coherency strains produced by the γ-γ’ lattice mismatch, δ, on the decomposition process of Ni-Al-Mo alloys with a bimodal size distribution is presented. Samples with δ ranging from positive to negative, were investigated in a double-step aging procedure. The evolution of the microstructure and the kinetics of coarsening were studied using transmission electron microscopy (TEM). The lattice mismatch between the matrix and the different classes of precipitates was determined by high-resolution high-temperature x-ray diffraction. It is shown that the strain fields produced by the lattice mismatch can influence dramatically the decomposition of metallic alloys. It is suggested that the reduction of the coarsening rate of the large precipitates, the fast coarsening rate of the small precipitates and the distortions detected in the matrix are all direct consequences of the elastic fields produced by the γ-γ’ lattice mismatch.

Preparation and characterization emulsion of PANI-TiO2 nanocomposite and its application as anticorrosive coating

2015 ◽  
Vol 35 (6) ◽  
pp. 597-603 ◽  
Author(s):  
Mohsen Khademian ◽  
Hossein Eisazadeh
Keyword(s):  
Electron Microscopy ◽  
Colloidal Particles ◽  
Aqueous Media ◽  
Corrosion Current ◽  
Ammonium Persulfate ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
The Matrix ◽  
Definition Of

Abstract Emulsion nanoparticles of polyaniline (PANI) were synthesized in the aqueous media by using hydroxylpropylcellulose (HPC) as a stabilizer and ammonium persulfate as an oxidant in the presence of TiO2 with nanometer size. New poly(vinyl acetate) (PVAc) coating over carbon steel was prepared by addition of emulsion nanoparticles in different concentrations (1%, 2% and 1.5%) in PVAc as the major matrix. The Tafel plot records were used for the definition of potential and corrosion current (Icorr). Nanoparticles were characterized and compared by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By adding TiO2, the thermal stability of the nanocomposite increased. A small size of colloidal particles prevented the precipitation of conducting polymer particles and led to better dispersion of nanocomposites in the matrix of the PVAc binder; therefore, the paint was homogeneous and anticorrosion properties of the coating increased. According to the results, 1.5% of PANI-TiO2 nanocomposite in PVAc has a much lower Icorr in NaCl aqueous solution and 2% of PANI-TiO2 nanocomposite in PVAc has the best corrosion protection in HCl.

scholarly journals Analytical and Numerical Methods for a Preliminary Assessment of the Remediation Time of Pump and Treat Systems

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2850
Author(s):  
Matteo Antelmi ◽  
Francesca Renoldi ◽  
Luca Alberti
Keyword(s):  
Groundwater Remediation ◽  
Transport Model ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Matrix Diffusion ◽  
Preliminary Evaluation ◽  
Pump And Treat ◽  
Advection Dispersion ◽  
The Matrix ◽  
Analytical Approaches

Several remediation technologies are currently used to address groundwater pollution. “Pump and treat” (P&T) is probably one of the most widely applied, being a process where contaminated groundwater is extracted from the subsurface by pumping and then treated before it is discharged or reinjected into the aquifer. Despite being a very adaptable technology, groundwater remediation is often achieved in long and unsustainable times because of limitations due to the hydrogeological setting and contaminant properties. Therefore, the cost–benefit analysis over time results in an inefficient system and a preliminary evaluation of the clean-up time is crucial. The aim of the paper is to compare, in an integrated manner, the application of some models to estimate the time to compliance of a P&T system in relation to the specific hydrogeological condition. Analytical solutions are analyzed and applied to an industrial site and to a synthetic case. For both cases, batch flushing and the advection-dispersion-retardation (ADR) model underestimate remediation times comparing the results to real or simulated monitoring data, whereas the Square Root model provided more reliable remediation times. Finally, for the synthetic case, the reliability of analytical approaches and the effects of matrix diffusion are tested on the basis of a numerical groundwater transport model specifically implemented, which confirm the results of the analytical methods and the strong influence of the matrix diffusion on the results.

Upconversion Luminescence Properties of NaYF4 Nanocrystals Precipitated Nd3+/Yb3+/Ho3+ Tri-Doped Oxyfluoride Glass Ceramics

2016 ◽  
Vol 16 (4) ◽  
pp. 3744-3748 ◽  
Author(s):  
Yuan Gao ◽  
Yuebo Hu ◽  
Dacheng Zhou ◽  
Jianbei Qiu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Transfer Process ◽  
Upconversion Luminescence ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Oxyfluoride Glass ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix

Transparent oxyflouride glass ceramics composed of SiO2–Al2O3–Na2O–NaF–YF3 tri-coped with Nd3+/Yb3+/Ho3+ were prepared by thermal treatment. Segregation of NaYF4 nanocrystals in the matrix was confirmed from structural analysis by means of X-ray diffraction and transmission electron microscopy. Compared with glass samples, very strong green upconversion (UC) luminescence due to the Ho3+:(4F5, 5S2)→5I8 transition was observed in the glass ceramics under 808 nm excitation. It was found that upconversion intensity of Ho3+ strongly depends on the Nd3+ concentration, and the energy transfer process from Nd3+ to Ho3+ via Yb3+ was proposed.

Effect of Milling Condition on Properties and Microstructure of Copper Reinforced with 1% vol. NbC

2007 ◽  
Vol 539-543 ◽  
pp. 826-831
Author(s):  
Marta López ◽  
José A. Jiménez ◽  
R. Benavente
Keyword(s):  
Fine Particles ◽  
Pure Copper ◽  
Microstructural Analysis ◽  
High Strength ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Mechanical And Electrical Properties ◽  
Composites Materials ◽  
Transmission Electron ◽  
Fine Microstructure

Composites materials consisting of pure copper reinforced with 1 vol.% of NbC were prepared by the powder metallurgy route to determine the influence of the milling process on the mechanical and electrical properties. For comparative purpose different milling times at four different rotational speeds were used. The resulting powders were consolidated by hot uniaxial pressing under 90MPa for 2h at 923K to obtain materials with a fine microstructure without residual porosity. It was found that the microstructure and properties of composite materials could be principally related to the amount of Fe, Cr, C and O incorporated as impurities during the milling process. Therefore, the rotational speeds used for milling has an important influence on the properties of the final product. A lower energy-ball milling is accompanied by a smaller amount of impurities (Fe, C and O) incorporated during milling. Composites materials combine electrical conductivity above 40% IACS with high strength. A detailed microstructural analysis by scanning and transmission electron microscopy and X ray diffraction showed that these properties are related not only to NbC particles, but also to the presence of very fine particles of carbides and oxides.

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