Rheological behavior of fresh cement pastes with a graphene oxide additive
Publication date: December 2016 Source:New Carbon Materials, Volume 31, Issue 6 Author(s): Qin Wang, Jian Wang, Chun-xiang Lv, Xi-you Cui, Shi-yu Li, Xi Wang The rheological properties and morphology of fresh cement pastes with different contents of graphene oxide (GO) were investigated by a rheometer and a laser confocal scanning microscope, respectively. The rheological data were fitted by the Modified-Bingham (M-B) model and Herschel-Bulkley (H-B) model. A mechanism for the effect of GO on the rheological properties is proposed. Results show that the cement particles are re-agglomerated and new flocculation stru...
Source: New Carbon Materials - January 23, 2017 Category: Chemistry Source Type: research
Large-scale synthesis of novel vertically-aligned helical carbon nanotube arrays
Publication date: December 2016 Source:New Carbon Materials, Volume 31, Issue 6 Author(s): Ji-cheng Zhang, Yong-jian Tang, Yong Yi, Kang-fu Ma, Min-jie Zhou, Wei-dong Wu, Chao-yang Wang The large-scale synthesis of vertically-aligned carbon nanotube arrays with different helical pitches and diameters was achieved using the floating catalyst method. Results indicate that they are aligned perpendicular to the substrate surface and have a well-graphitized structure and their growth is accompanied by the production of pentagonal, heptagonal and hexagonal carbon rings. The hexagonal carbon ring is the basic structure u...
Source: New Carbon Materials - January 23, 2017 Category: Chemistry Source Type: research
The densification mechanism of polyacrylonitrile carbon fibers during carbonization
Publication date: October 2016 Source:New Carbon Materials, Volume 31, Issue 5 Author(s): Quan-sheng Ma, Ai-jun Gao, Yuan-jian Tong, Zuo-guang Zhang The densification mechanism of polyacrylonitrile carbon fibers during carbonization from 900 to 1 400 °C was investigated. The density, elemental composition, microstructure and weight loss of the fibers, as well as the gases released during the process were analyzed to reveal the mechanism. Results indicated that the density of the fibers was strongly dependent on the carbonization temperature and reactions involved indifferent temperature regimes. Condensation, pyroly...
Source: New Carbon Materials - November 11, 2016 Category: Chemistry Source Type: research
Changing the chirality of single-wall carbon nanotubes during epitaxial growth : A density functional theory study
Publication date: October 2016 Source:New Carbon Materials, Volume 31, Issue 5 Author(s): Wei Shen, Feng Li, Chang Liu, Li-chang Yin The energetic of the change in the chirality of single-wall carbon nanotubes (SWCNTs)during epitaxial growth from (n, m) to (n±Δ, mΔ)(Δ=1, 2) was investigated by density functional theory calculations. The calculated energies for changing the chirality of different SWCNTs show a nearly linear decrease with decreasing tube diameter. In the case ofΔ=1, more energy input is needed for near armchair (nAC) SWCNTs to change their chiralities than those for near zigzag (nZZ) SWCNTs with c...
Source: New Carbon Materials - November 11, 2016 Category: Chemistry Source Type: research
Preparation of nano-diamond films on GaN with a Si buffer layer
Publication date: October 2016 Source:New Carbon Materials, Volume 31, Issue 5 Author(s): Jin-long Liu, Han-mei Tian, Liang-xian Chen, Jun-jun Wei, Li-fu Hei, Cheng-ming Li Gallium nitride (GaN) has been widely used in electronic and optoelectronic devices because of its unique electrical properties. However, its low thermal conductivity and the high thermal boundary resistance at the interface between GaN and substrates such as Si and Al2O3preventefficient heat dissipation from the heated regions, which limits the further development of GaN-based high power devices. Diamond, with the highest thermal conductivity, ...
Source: New Carbon Materials - November 11, 2016 Category: Chemistry Source Type: research
Removal of Cr(VI) from aqueous solution by pyrolytic charcoals
Publication date: October 2016 Source:New Carbon Materials, Volume 31, Issue 5 Author(s): Türkan Altun, Yakup Kar Bio-chars produced by the pyrolysis of walnut shells at 450 °C (BC450)and theco-pyrolysis of walnut shells and 20 wt% tar sand (BCTS20)at the same temperature, were investigated as potential adsorbents for the removal of Cr(VI) ions from aqueous solutions using batch experiments. The BCTS20 has more abundant surface functional groups than BC450. The Cr(VI) removal percentages under optimal conditions were 80.47 and 95.69%for BC450 and BCTS20, respectively. Langmuir, Freundlich and D-R models were used to ...
Source: New Carbon Materials - November 11, 2016 Category: Chemistry Source Type: research
Optimizing the preparation conditions of activated carbons from olive cake using KOH activation
Publication date: October 2016 Source:New Carbon Materials, Volume 31, Issue 5 Author(s): Nour T. Abdel-Ghani, Ghadir A. El-Chaghaby, Mohamed H. ElGammal, El-Shaimaa A. Rawash Activated carbons were prepared from olive cake waste by KOH activation. A full factorial 23 experimental design was used to optimize their preparation conditions. The factors and levels included are activation temperature (600 and 900 °C), activation time (1 and 3 h) and impregnation ratio (1:2 and 1:4). The surface area of the activated carbons was chosen as a measure of the optimization. The surface and pore properties of the activated carb...
Source: New Carbon Materials - November 11, 2016 Category: Chemistry Source Type: research
Porous carbons produced by the pyrolysisof green onion leaves and their capacitive behavior
Publication date: October 2016 Source:New Carbon Materials, Volume 31, Issue 5 Author(s): Jing Yu, Li-zhen Gao, Xue-lian Li, Chao Wu, Li-li Gao, Chang-ming Li Porous carbons were prepared by the simple carbonization of green onion leaves at temperatures from 600 to 800 °C and used as the electrode materials of supercapacitors. SEM, FESEM, EDX, AAS, XRD, TGA and nitrogen adsorption were used to characterize their morphology, pore structure and surface elemental composition. Cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge were carried out to evaluate their specific capac...
Source: New Carbon Materials - November 11, 2016 Category: Chemistry Source Type: research
Preparation of carbon nanospheres by non-catalytic chemical vapor deposition and their formation mechanism
Publication date: October 2016 Source:New Carbon Materials, Volume 31, Issue 5 Author(s): You Zhang, Wei Yang, Rui-ying Luo, Hai-dong Shang Carbon spheres with different sizes were prepared by non-catalytic chemical vapor deposition fromgas mixtures of CH4 and H2. The influence of the deposition temperature, pressure, and gas ratio on the formation and growth mechanism of the spheres was investigated. The carbon spheres obtained were characterized by XRD, SEM and TEM. Results indicated that carbon nanospheres (50–100 nm) could be obtained at 1150°C and 5 kPa from a gas mixture with a CH4/H2 volume ratio of 0.25. T...
Source: New Carbon Materials - November 11, 2016 Category: Chemistry Source Type: research
Influence of ZrC on the microstructure of its surrounding resin-based carbon at high temperature
Publication date: August 2016 Source:New Carbon Materials, Volume 31, Issue 4 Author(s): Zhong-wei Zhang, Min Mei, Liang Li, Ce-wen Nan, Jun-shan Wang, Zheng-hui Xu The microstructures of a refractory ZrC particle and its surrounding resin-based carbon treated above 2500 °C were investigated by SEM, TEM, HRTEM and selected area electron diffraction. Results show that the ZrC particle is enclosed by a transition carbon layer that has a d 002 of 0.3375 nm, close to that of ideal graphite, indicating the formation of a well graphitized structure. The carbon far away from the ZrC particle remains isotropic and amorpho...
Source: New Carbon Materials - September 17, 2016 Category: Chemistry Source Type: research
Bend properties and failure mechanism of a carbon/carbon composite with a 3D needle-punched preform at room and high temperatures
Publication date: August 2016 Source:New Carbon Materials, Volume 31, Issue 4 Author(s): Dian-sen Li, Qian-qian Yao, Nan Jiang, Lei Jiang A 3D needle-punched C/C composite with a high density was fabricated and its bend properties were investigated at room and high temperatures. Macro-fracture and SEM micrographs were examined to understand the deformation and failure mechanism. Results show that the load-deflection curves below 400 °C exhibit a linear elastic and brittle fracture failure, while the curves at temperatures above 500 °C show an obvious tough and plastic failure. The bend strength and modulus decrease...
Source: New Carbon Materials - September 17, 2016 Category: Chemistry Source Type: research
Modification of asphalt by dispersing waste polyethylene and carbon fibers in it
Publication date: August 2016 Source:New Carbon Materials, Volume 31, Issue 4 Author(s): Mao-rong Zhang, Chang-qing Fang, Shi-sheng Zhou, You-liang Cheng, Jing-bo Hu Recycled waste packaging polyethylene (WPE) and chopped polyacrylonitrile-based carbon fibers (PAN-CFs) were dispersed in molten asphalt at 170 °C with a shearing machine at 3 800 r/min for 60 min to modify its properties to meet the demands of motorway paving. WPE and PAN-CFs were mixed by three methods before the dispersion: (a) simple blending, (b) first dissolving WPE in xylene, then mixing and evaporating and (c) blending and extrusion to rods of ...
Source: New Carbon Materials - September 17, 2016 Category: Chemistry Source Type: research
The use of carbon nanotube yarn as a filter medium to treat nitroaromatic-contaminated water
This study demonstrates the ability of CNTY to remove organic contaminants from water. (Source: New Carbon Materials)
Source: New Carbon Materials - September 17, 2016 Category: Chemistry Source Type: research
An asymmetrical activated carbon electrode configuration for increased pore utilization in a membrane-assisted capacitive deionization system
Publication date: August 2016 Source:New Carbon Materials, Volume 31, Issue 4 Author(s): Jiyoung Kim, Dong-Hyun Peck, Byungrok Lee, Seong-Ho Yoon, Doo-Hwan Jung A membrane-assisted capacitive deionization (CDI) system was developed for the purification of water containing sodium chloride using activated carbon fibers (ACFs) as capacitor electrode materials. The ACFs have different degrees of activation with different surface areas and pore size distributions. Their desalination performance for sodium or chloride ions was investigated. Results indicate that the salt removal efficiency and surface area-normalized elec...
Source: New Carbon Materials - September 17, 2016 Category: Chemistry Source Type: research
Hydrothermal synthesis of porous phosphorus-doped carbon nanotubes and their use in the oxygen reduction reaction and lithium-sulfur batteries
Publication date: June 2016 Source:New Carbon Materials, Volume 31, Issue 3 Author(s): Meng-qing Guo, Jia-qi Huang, Xiang-yi Kong, Hong-jie Peng, Han Shui, Fang-yuan Qian, Lin Zhu, Wan-cheng Zhu, Qiang Zhang The many uses of carbon nanotubes (CNTs) depend not only on their intrinsic physical properties, but also on their tunable chemical components. Exploring a low-temperature method for the incorporation of phosphorus atoms in the carbon framework is expected to change the chemical properties of CNTs. Here, phosphorus-functionalized CNTs (PCNTs) were prepared by the direct hydrothermal treatment of a CNT-H3PO4 ...
Source: New Carbon Materials - August 11, 2016 Category: Chemistry Source Type: research
