scholarly journals Durability Characterisation of Portland Cement–Carbon Nanotube Nanocomposites

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4097
Author(s):  
Alastair J. N. MacLeod ◽  
Will P. Gates ◽  
Frank Collins
Keyword(s):  
Portland Cement ◽  
Water Pressure ◽  
High Water ◽  
Chloride Diffusion ◽  
Cement Composites ◽  
Multiwalled Carbon ◽  
Pore Networks ◽  
Chloride Uptake ◽  
Computed Microtomography ◽  
X Ray Computed

Multiwalled carbon nanotubes have outstanding mechanical properties that, when combined with Portland cement, can provide cementitious composites that could lead to the innovative construction of stronger, lighter, and thinner built infrastructure. This paper addresses a knowledge gap that relates to the durability of CNT–cement composites. The durability to corrosive chloride, uptake of water by sorption, and flow of the permeability of water acting under high water pressure are addressed. Flow simulations were undertaken through segmented 3D pore networks, based on X-ray computed microtomography measurements, the creation of a virtual microstructure, and fluid simulations that were compared with larger-scale samples. The investigation showed decreased water sorptivity of CNT–cement mixtures, indicating improved durability for the cover zone of concrete that is prone to the uptake of water and water-borne corrosives. Chloride diffusion of CNT–cement composites provided up to 63% improvement compared with control samples. The favourable durability bodes well for the construction of long-life CNT-reinforced concrete infrastructure.

Multiwalled Carbon Nanotubes Reinforced Portland Cement Composites for Smoke Detection

2012 ◽  
Vol 185 ◽  
pp. 21-24 ◽  
Author(s):  
Prashant Shukla ◽  
Vasuda Bhatia ◽  
Vikesh Gaur ◽  
Rupesh Kumar Basniwal ◽  
Budhendra Kumar Singh ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Ionic Conductivity ◽  
Portland Cement ◽  
Multiwalled Carbon Nanotubes ◽  
Carbon Fibers ◽  
Room Temperature ◽  
Porous Matrix ◽  
Cement Composites ◽  
Smoke Detection ◽  
Multiwalled Carbon

Smoke detection with multiwalled carbon nanotubes (MWCNTs)/cement composites have been studied. Pellets of MWCNTs reinforced Portland cement have been casted with varying MWCNTs %. The DC transient studies depicted an increase in conductivity when exposed to smoke. Responsivity in the range 26-46% has been obtained under smoky environment based on MWCNTs % in the composites. Ionic conductivity increased with frequency at room temperature under ambient and smoky environments. In this paper, we also report fabrication technique of the pellets and the sensing mechanism is explained on the basis of ionic conductivity of the cementitious material in combination with the conductive carbon fibers present in the porous matrix of the cement.

Determination of reservoir rock residual water using X-ray computed microtomography

2018 ◽  
pp. 38-42 ◽  
Author(s):  
I.V. Yazynina ◽  
◽  
E.V. Shelyago ◽  
A.A. Abrosimov ◽  
N.E. Grachev ◽  
...  
Keyword(s):  
Reservoir Rock ◽  
Residual Water ◽  
X Ray ◽  
Computed Microtomography ◽  
X Ray Computed

Acoustic emission and X-ray computed microtomography characterization of damage accumulation in a woven Cf/SiC composite

2019 ◽  
Vol 155 ◽  
pp. 109748
Author(s):  
Yudong Xue ◽  
Qinglei Wang ◽  
Jianbao Hu ◽  
Haijun Zhou ◽  
Qingliang Shan ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Damage Accumulation ◽  
X Ray ◽  
Computed Microtomography ◽  
X Ray Computed

scholarly journals Short-term Variations in Strain and Surface Tilt on Storglaciären, Kebnekaise, Northern Sweden

1989 ◽  
Vol 35 (120) ◽  
pp. 201-208 ◽  
Author(s):  
Peter Jansson ◽  
Roger LeB. Hooke
Keyword(s):  
Water Pressure ◽  
High Water ◽  
Ice Thickness ◽  
Gradual Change ◽  
Short Term ◽  
Glacier Surface ◽  
Vertical Movements ◽  
Bed Topography ◽  
The Waves ◽  
Local Uplift

AbstractTiltmeters that can detect changes in slope of a glacier surface as small as 0.1 μ rad have been used on Storglaciären. The records obtained to date have been from the upper part of the ablation area, where the bed of the glacier is overdeepened. A total of 82 d of records has been obtained for various time periods between early June and early September.There is generally a gradual change in inclination of the glacier surface over periods of several days, but these changes do not appear to be systematic. In particular, they are not consistent with vertical movements of stakes located 2–3 ice thicknesses away from the tiltmeters. This suggests that the tiltmeters are sensing disturbances over areas with diameters comparable to the local ice thickness.Superimposed on these trends are diurnal signals suggesting rises and falls of the surface just up-glacier from the riegel that bounds the overdeepening on its down-glacier end. These may be due to waves of high water pressure originating in a crevassed area near the equilibrium line. If this interpretation is correct, the waves apparently move down-glacier at speeds of 20–60 m h−1and become sufficiently focused, either by the bed topography or by conduit constrictions, to result in local uplift of the surface. Also observed are abrupt tilts towards the glacier center line shortly after the beginning of heavy rainstorms. These appear to be due to longitudinal stretching as the part of the glacier below the riegel accelerates faster than that above. Water entering the glacier by way of a series of crevasses over the riegel is believed to be responsible for this differential acceleration. In June 1987, a dramatic event was registered, probably reflecting the initial summer acceleration of the glacier.

scholarly journals Author Correction: A quantitative analysis of 3D-cell distribution in regenerative muscle-skeletal system with synchrotron X-ray computed microtomography

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Markéta Tesařová ◽  
Lucia Mancini ◽  
Andras Simon ◽  
Igor Adameyko ◽  
Markéta Kaucká ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Cell Distribution ◽  
Skeletal System ◽  
X Ray ◽  
Computed Microtomography ◽  
X Ray Computed

X-ray computed microtomography for the structural analysis of jewelry from the Museum “Royal Tombs of Sipán”

2020 ◽  
Vol 35 (S1) ◽  
pp. S38-S42
Author(s):  
Soraia Rodrigues de Azeredo ◽  
Roberto Cesareo ◽  
Angel Guillermo Bustamante Dominguez ◽  
Ricardo Tadeu Lopes
Keyword(s):  
Structural Analysis ◽  
High Resolution ◽  
Copper Alloys ◽  
North Coast ◽  
Flat Panel ◽  
X Ray ◽  
The North ◽  
Gold Silver ◽  
Computed Microtomography ◽  
X Ray Computed

Precious ornaments from the Museum Royal Tombs of Sipán were analyzed by X-ray computed microtomography (microCT). The ornaments analyzed were golden earrings produced by the Moche culture that flourished along the north coast of present-day Peru between approximately 100 and 600 AD. Sipán, also known as Huava Rajada, is a mochica archaeological complex in the north of Peru. In particular, the spectacular jewelry, mainly composed of gold, silver, and copper alloys, gilded copper, and tumbaga, from the Museum “Royal Tombs of Sipán,” in Lambayeque, north of Peru, are some of the most sophisticated metalworking ever produced of pre-Columbian America. A portable microCT system consisting of a high-resolution flat panel detector and a mini X-ray tube were used for the structural analysis of these ornaments. The microCT images show parts of the internal structure, highlighting the manufacturing technique and gold sheets joining techniques of the Moche artisans. Furthermore, the advantage of using the portable microCT system for nondestructive testing is clear when the sample cannot be taken to the laboratory.

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