Effect of Multi Walled Carbon Nanotubes Incorporated on Refractory Castables

2016 ◽  
Vol 881 ◽  
pp. 475-480
Author(s):  
Norval Rodrigues de Oliveira Jr. ◽  
Fabíola A.S. Ribeiro ◽  
Gustavo C. Salles ◽  
Clascídia A. Furtado ◽  
Modestino A. Brito ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Modulus Of Rupture ◽  
Outer Diameter ◽  
Water Addition ◽  
Refractory Castables ◽  
Mwcnt Concentration ◽  
Different Types ◽  
Negative Effect ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Two different types of multi walled carbon nanotubes (MWCNT) were introduced in a calcium aluminate refractory castable used in steelmaking process. The first MWCNT was purchased from Cheap Tubes (USA), a hydroxyl (-OH) functionalized, outer diameter of 50-80 nm, length of 10-20 μm, and, the second one was supplied by Nanocyl (Belgium), not functionalized, outer diameter of 9.5 nm, and length of 1.5 μm. Both types of MWCNT were incorporated into the dry castable mixture before water addition. The workability and properties of the final product, such as apparent density, apparent porosity and hot modulus of rupture were evaluated. The nanocarbons were characterized by SEM, TEM, TGA and Raman spectroscopy. In both cases, the incorporation of MWCNT had a negative effect on the rheology of wet castables, decreasing their workability. No significant improvements on mechanical properties of the castables were observed with the incorporation until MWCNT concentration reached 0.15 % (m/m), except for the increase of hot modulus of rupture observed for Cheap Tubes MWCNT introduction.

scholarly journals Multi-walled carbon nanotube doped PVA membrane for desalination

2018 ◽  
Vol 19 (4) ◽  
pp. 1229-1237 ◽  
Author(s):  
B. Yilman ◽  
F. U. Nigiz ◽  
A. Aytaç ◽  
N. D. Hilmioglu
Keyword(s):  
Carbon Nanotubes ◽  
Sem Analysis ◽  
Multi Walled Carbon Nanotube ◽  
Mwcnt Concentration ◽  
Degree Of Swelling ◽  
Excess Amount ◽  
Different Types ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Scanning Electron

Abstract In this study, multi-walled carbon nanotubes (MWCNT) loaded polyvinyl alcohol (PVA) membranes were synthesized and applied for desalination by means of pervaporation technique. Membranes were characterized using scanning electron microscope (SEM). Sorption studies were carried out to determine the degree of swelling of the MWCNT/PVA membranes into different types of salt solution. Pervaporation experiments were carried using the pristine and MWCNT loaded membranes. The effect of MWCNT concentration and salt concentration on the swelling, flux and salt rejection were investigated at the constant temperature of 40 °C. As a result, greater than 92% of rejections were obtained using all membrane. The highest flux was obtained using 0.3 wt% MWCNT loaded membrane with the highest rejection of 98.8%. SEM analysis confirmed that the excess amount of particles caused agglomeration and negatively affected the desalination performance.

scholarly journals STUDY OF MUTAGENIC ACTIVITY NANO- AND MICROPARTICLES IN THE AMES TEST (SALMONELLA / MICROSOME)

2019 ◽  
Vol 98 (4) ◽  
pp. 455-460
Author(s):  
Lyudmila V. Akhaltseva ◽  
V. S. Zhurkov ◽  
L. P. Sycheva ◽  
O. N. Savostikova ◽  
A. V. Alekseeva
Keyword(s):  
Carbon Nanotubes ◽  
Ames Test ◽  
Mutagenic Activity ◽  
Dose Range ◽  
Gene Mutations ◽  
Outer Diameter ◽  
Multi Walled Carbon Nanotubes ◽  
Inner Diameter ◽  
Substitution Mutations ◽  
Walled Carbon Nanotubes

Introduction. One of the important steps in assessing the nanoparticles (NP) safety is the analysis of mutagenic activity, including the evaluation of gene, chromosomal, and genomic mutations. Material and methods. The purpose of this investigation is to study the ability of different NP aqueus suspensions and the same compounds in microforms to unduce gene mutations in Salmonella/microsome test (Ames test). Anatase titanium dioxide NP coated with simethicone (33.16 ± 16.7 nm, 5-50000 μg/ml), magnetite NP coated with silicate (10 nm, 0.92-575 μg/ml), silver NP coated with аrabian gum (14 ± 0.2 nm, 5-50000 μg/ml), aluminum hydroxide nanofibres (50-70 nm, 24-3000 μg/ml) and multi-walled carbon nanotubes (Taunit MWСNTs, outer diameter 15-40 nm, inner diameter 3-8 nm, length 2 and more microns, 5-50000 μg/ml). In parallel, the mutagenic activity of equivalent microparticles was evaluated in experiments. Ames test (Salmonella/microsomes) registers gene mutations induced by a different mechanism of action, in the variant with preincubation. A set of Salmonella typhimurium indicator strains: TA 100 (base pair substitution mutations), TA 98 and TA 97 (mutations of the frameshift type of the genetic code) were used. Using addition the S9 microsomal activating mixture during the experiment makes it is possible to determine the effect not only of the substances themselves, but also of their metabolites. Conclusion. The investigated nanomaterials as well as their micro analogs in the studied dose range did not induce gene mutations in the Ames test both in presence and absence microsomal activating mixture.

Characterization of Carbon Nanotube Growth via CVD Synthesis from a Liquid Precursor

2014 ◽  
Vol 23 (01n02) ◽  
pp. 1420001 ◽  
Author(s):  
Carol Jenkins ◽  
Melissa Cruz ◽  
Jen Depalma ◽  
Michael Conroy ◽  
Barbara Benardo ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Conditions ◽  
Outer Diameter ◽  
Carrier Gas ◽  
Phase Precursor ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Nanotube Growth ◽  
Nanotube Growth ◽  
Walled Carbon Nanotubes

As novel theories and uses of carbon nanotubes (CNT) advance, it becomes increasingly important to characterize the methods of production. One such method of CNT production uses a liquid phase precursor (hydrocarbon with nanoparticle catalyst mix) that is injected into a tube furnace with a flowing carrier gas. The CNTs are grown in high purity and are collected on the surface of the quartz tube. The system allows for a number of variables to be tested such as growth temperatures, flow rate of the carrier gas, precursor injection rates and variations of precursor mix however, here only thermal effects are considered. Under thermal conditions ranging from 500 to 850°C, multi-walled carbon nanotubes (MWCNTs) are synthesized and characterized to determine inner and outer diameter as well as tube thickness.

Fabrication and Properties of Multi-Walled Carbon Nanotubes Buckypaper

2015 ◽  
Vol 1108 ◽  
pp. 33-38 ◽  
Author(s):  
W.A.D. Wan Dalina ◽  
M. Mariatti ◽  
Soon Huat Tan ◽  
Z.A. Mohd Ishak ◽  
Abdul Rahman Mohamed
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
High Performance ◽  
Free Standing ◽  
Filtration Process ◽  
Different Types ◽  
Multi Walled Carbon Nanotubes ◽  
Triton X ◽  
Walled Carbon Nanotubes

Free-standing carbon nanotubes (CNTs) film known as buckypaper is a method used to address dispersion problems of CNTs. Unique properties of CNTs made the CNTs buckypaper to be considered as promising reinforcement materials in development of high-performance of nanocomposites. Buckypaper was fabricated by dispersing multi-walled carbon nanotubes (MWCNTs) in two different types of solution namely Triton X-100 and ethanol then followed by filtration process. In this study, MWCNTs loading and pressure used during filtration process were manipulated. The morphology, thermal and electrical conductivity of the buckypaper produced was studied.

scholarly journals Optimization of growth temperature of multi-walled carbon nanotubes fabricated by chemical vapour deposition and their application for arsenic removal

2014 ◽  
Vol 32 (4) ◽  
pp. 709-718 ◽  
Author(s):  
S. Mageswari ◽  
S. Kalaiselvan ◽  
P. Syed Shabudeen ◽  
N. Sivakumar ◽  
S. Karthikeyan
Keyword(s):  
Carbon Nanotubes ◽  
Electron Microscope ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Spectral Studies ◽  
Outer Diameter ◽  
Chemical Vapour Deposition Technique ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

AbstractMulti-walled carbon nanotubes have been synthesized at different temperatures ranging from 550 °C to 750 °C on silica supported Fe-Mo catalyst by chemical vapour deposition technique using Cymbopogen flexuous oil under nitrogen atmosphere. The as-grown MWNTs were characterized by scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM), X-ray diffraction analysis (XRD) and Raman spectral studies. The HRTEM and Raman spectroscopic studies confirmed the evolution of MWNTs with the outer diameter between 20 and 40 nm. The possibility of using as-grown MWNTs as an adsorbent for removal of As (V) ions from drinking water was studied. Adsorption isotherm data were interpreted by the Langmuir and Freundlich equations. Kinetic data were studied using Elovich, pseudo-first order and pseudo-second order equations in order to elucidate the reaction mechanism.

Investigation on Friction, Anti-wear, and Extreme Pressure Properties of Different Grades of Polyalphaolefins With Functionalized Multi-walled Carbon Nanotubes as an Additive

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Homender Kumar ◽  
A. P. Harsha
Keyword(s):  
Carbon Nanotubes ◽  
Friction And Wear ◽  
Outer Diameter ◽  
Test Results ◽  
Extreme Pressure ◽  
Wear Properties ◽  
Multi Walled Carbon Nanotubes ◽  
Friction And Wear Properties ◽  
Analytical Tools ◽  
Walled Carbon Nanotubes

Abstract In the present investigation, the COOH-functionalized multi-walled carbon nanotubes (MWCNTs) having an outer diameter of 20–30 nm and length 1−2 μm were dispersed in four different grades of polyalphaolefins (PAOs; i.e., PAO 4, PAO 6, PAO 40, and PAO 100) at various concentrations (0.025, 0.05, 0.075, 0.10, and 0.15 wt%) to evaluate friction, anti-wear, and extreme pressure properties. The tribological test was conducted as per ASTM standard using four-ball tester. The test results showed that with the addition of MWCNTs, the friction and wear properties of PAOs had been improved significantly as compared to the base oils. It was also observed that MWCNTs exhibited excellent anti-wear properties than friction properties. The possible reasons for the improvement in friction and wear properties are discussed with the aid of various analytical tools.

The kinetic and thermodynamic analysis of Li+ in multi-walled carbon nanotubes

2004 ◽  
Vol 835 ◽  
Author(s):  
Kezhi Lin ◽  
Yanhui Xu ◽  
Xiaolin Wang
Keyword(s):  
Carbon Nanotubes ◽  
Diffusion Coefficient ◽  
Carbon Materials ◽  
Reversible Capacity ◽  
Electrochemical Intercalation ◽  
Different Types ◽  
Multi Walled Carbon Nanotubes ◽  
Kinetic And Thermodynamic Analysis ◽  
Walled Carbon Nanotubes ◽  
Electrochemical Intercalation Reaction

AbstractThe multi-walled carbon nanotubes (MWNTs) prepared by CVD were used in electrochemical intercalation reaction with Li+. The results of the first several charge-discharge cycles showed that the reversible capacity of the MWNTs was larger than the theoretical capacity of graphitized carbon. The equivalent circuit of the Li+ intercalated into the MWNTs was simulated The diffusion coefficient calculated based on the results of the impedance was in the range between 1 ∼ 4×10−10 cm2s−1. The diffusion coefficient calculated based on the technique of the chronoamperometery was 3.5×10−10 cm2s−1. The diffusion coefficients of the Li+ reacted with MWNTs was in the range of that of the most carbon materials. Using EMF method the partial molar entropy (ΔSx) and partial molar enthalpy (ΔHx) of the Li+ intercalated into the MWNTs were calculated as a function of × in Lix C6 at different temperatures. The values of ΔSx were in the range of 150 ∼ 550 J mol-1K-1. The values of ΔHx at 35 °C were in the range of 40∼110 kJ mol−1. Both of the ΔSx and ΔHx were lower and the changes were smaller than the values of some other carbonaceous materials. By analyzing the results conclusion is obtained that Li+ exist in MWNTs with different types which include adsorption and intercalation types.

INFLUENCE OF CURVATURE OF GRAPHENE LAYERS OF MULTI-WALLED CARBON NANOTUBES ON ELECTRICAL PROPERTIES

2009 ◽  
Vol 08 (01n02) ◽  
pp. 1-4 ◽  
Author(s):  
A. I. ROMANENKO ◽  
O. B. ANIKEEVA ◽  
T. I. BURYAKOV ◽  
E. N. TKACHEV ◽  
K. R. ZHDANOV ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Carbon Nanotubes ◽  
Electrical Properties ◽  
Quantum Corrections ◽  
Electron Interaction ◽  
Outer Diameter ◽  
Graphene Layers ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

We investigated temperature and magnetic field dependences of conductivity of multi-walled carbon nanotubes (MWNTs) with different average outer diameter. We separated out the quantum corrections to magnetoconductivity for interaction electrons and determined the dependence of constant of electron–electron interaction λ versus curvature of graphene layers in MWNTs.

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