Tensometry of carbon fibres and elastomers at the diffractometer at BL20B of the Photon Factory

1998 ◽  
Vol 5 (3) ◽  
pp. 958-961
Author(s):  
D. C. Creagh ◽  
P. M. O'Neill ◽  
R. J. Mills ◽  
S. A. Holt
Keyword(s):  
Carbon Fibre ◽  
Duty Cycle ◽  
Simultaneous Recording ◽  
The Other ◽  
Imaging Plate ◽  
Relaxation Processes ◽  
Carbon Fibres ◽  
Fixed Rate ◽  
Photon Factory ◽  
System Use

Two systems have been developed for the simultaneous recording of the SAXS and the WAXS patterns from carbon fibre and elastomer samples which are placed under stress. The systems have been designed to fit inside the versatile vacuum diffractometer (BIGDIFF) at the Photon Factory. In one system, use is made of the ability to move the imaging-plate cassette. In the other, use has been made of an imaging-plate changer which can deliver up to 13 plates into position with a duty cycle of about 60 s. In this case each imaging plate can record SAXS/WAXS patterns in the range 0.5–20° due to the passage of the beam through the specimen which is mounted in a specially designed tensometer. Because BIGDIFF is a vacuum diffractometer and parasitic scattering is small, exposure times as short as 2 s can give acceptable SAXS/WAXS patterns. The systems have been used for the study of both the change of structure with strain, and the relaxation processes which occur as a result of the sample being strained at a fixed rate by a predetermined amount.

Non-Cottrell Behavior of the Dopamine Redox Reaction Observed on the Carbon Fibre Microelectrode by the Double-Step Voltcoulometry

2004 ◽  
Vol 69 (2) ◽  
pp. 419-425 ◽  
Author(s):  
Katarína Gmucová ◽  
Jozef Orlický ◽  
Juraj Pavlásek
Keyword(s):  
Carbon Fibre ◽  
Redox Reaction ◽  
Measured Data ◽  
The Other ◽  
Diffusion Current ◽  
Double Step ◽  
Dopamine Concentration ◽  
Living Body ◽  
Carbon Fibre Microelectrode ◽  
Experimental Errors

The redox reaction of the neurotransmitter dopamine at the carbon fibre microelectrode was studied by several electrochemical methods. It was found that under conditions usual in a living body, the diffusion current fullfils, within experimental errors, the behavior theoretically predicted by the Cottrell equation. Nevertheless, attention should be paid to the fact that unsupported or weakly supported conditions give rise to a non-Cottrell response of diffusion current. Moreover, similar changes were observed if the dopamine concentration was either lower such as several units of μmol l-1, or about 100 μmol l-1 or higher. The non-Cottrell behavior of diffusion current involves the nonlinearity of the dopamine calibration curve obtained by pulse techniques. The present work is aimed at pointing out that such behavior of the measured data could lead to misinterpretation of the obtained dopamine concentration. Similar features could be also achieved for the other catecholamines.

Electrocoating of carbon fibres: A route for interface control in carbon fibre reinforced poly methylmethacrylate?

2005 ◽  
Vol 65 (10) ◽  
pp. 1564-1573 ◽  
Author(s):  
Alexander Bismarck ◽  
Adam F. Lee ◽  
A. Sezai Saraç ◽  
Eckhard Schulz ◽  
Karen Wilson
Keyword(s):  
Carbon Fibre ◽  
Carbon Fibres ◽  
Interface Control

PROCESSING OF ULTRA-HIGH TEMPERATURE CERAMIC MATRIX COMPOSITES (UHTCMCS) THROUGH RF ENHANCED CHEMICAL VAPOUR INFILTRATION (RF-CVI)

2021 ◽  
Author(s):  
VINOTHINI VENKATACHALAM, ◽  
JON BINNER ◽  
THOMAS REIMER ◽  
BUCKARD ESSER ◽  
STEFANO MUNGIGUERRA ◽  
...  
Keyword(s):  
High Temperature ◽  
Carbon Fibre ◽  
Chemical Vapor Infiltration ◽  
Matrix Composites ◽  
Carbon Fibres ◽  
Temperature Oxidation ◽  
Ceramic Phase ◽  
Wide Range ◽  
The University ◽  
Ultra High Temperature

Carbon fibre (Cf) reinforced Ultra High Temperature Ceramic (UHTC) Matrix Composites (UHTCMCs) have proven to be excellent materials that can survive nearly 3000°C in highly oxidizing environments along with a good specific strength. Consequently, they have excellent potential for use in aerospace applications such as rocket nozzle throats and thermal protection systems (TPS). Due to the presence of the carbon fibres, UHTCMCs offer high strength and modulus combined with excellent thermal shock behaviour whilst the presence of the ultra-high temperature ceramic phase protects the carbon fibres at the application temperatures. High temperature oxidation, thermal ablation behaviour and mechanical properties of the UHTCMC’s relies heavily on the bonding between the carbon fibre and matrices especially the oxides formed to avoid any progressive failure and predict the life of the components. In the present investigation, a radio frequency assisted chemical vapor infiltration (RF-CVI) technique has been used to make the 2.5D Cf reinforced ZrB2, ZrB2/carbon matrices composites with various interphase materials. The advantage of RF heating is that it creates an inverse temperature profile in the sample, which means that the infiltration starts from inside and progresses outwards. This allows the time needed for processing to be reduced very significantly compared to the conventional CVI process. This presentation will report on the latest results from the research that has been undertaken at the University of Birmingham, including the results from a wide range of testing that has been undertaken at both DLR in Germany and the University of Naples in Italy.

Stochastic Theory of Human Slipping

2002 ◽  
Author(s):  
Ralph L. Barnett ◽  
Susanne A. Glowiak ◽  
Peter J. Poczynok
Keyword(s):  
Friction Coefficient ◽  
Duty Cycle ◽  
Stochastic Theory ◽  
The Other ◽  
Extreme Value Statistics ◽  
Conventional Theory ◽  
Low Friction ◽  
Friction Coefficients ◽  
Duty Cycles ◽  
New Concepts

The conventional approach to human slipping is essentially deterministic; it states that no slipping will occur when the average friction coefficient is greater than some critical friction criterion. Under this condition, pedestrians will not slip when they encounter the average friction coefficient. On the other hand, to successfully negotiate a walk of n-steps they must not slip when they encounter the smallest of the n friction coefficients. Consequently, a new slip theory has been formulated as a problem in extreme value statistics. An elegant relationship is obtained among the probability of slipping, the critical friction criterion, the number of steps taken by the walker, and the central measure, scatter, and asymmetry of the distribution of friction coefficients. The new theory reveals the structure of human slipping in a startling way that introduces completely new concepts: the go/no go nature of classical slip predictions is replaced by a probability of slipping; low friction floor/footwear couples may lead to fewer slips than high friction ones; slipping can occur in any case where conventional theory predicts “no slip”; and the number of slips depends on the distance traveled by a pedestrian. Finally, this paper develops the idea that the slipperiness of a real floor must be evaluated for a duty-cycle. Duty-cycles can be represented as frequency histograms when a floor is homogeneous and isotropic.

scholarly journals Effect of Carbon Nanotube Deposition Time to the Surface of Carbon Fibres on Flexural Strength of Resistance Welded Carbon Fibre Reinforced Thermoplastics Using Carbon Nanotube Grafted Carbon Fibre as Heating Element

2019 ◽  
Vol 3 (1) ◽  
pp. 9 ◽  
Author(s):  
Kazuto Tanaka ◽  
Takanobu Nishikawa ◽  
Kazuhiro Aoto ◽  
Tsutao Katayama
Keyword(s):  
Shear Strength ◽  
Carbon Nanotube ◽  
Flexural Strength ◽  
Carbon Fibre ◽  
Deposition Time ◽  
Heating Element ◽  
Resistance Heating ◽  
Carbon Fibres ◽  
Lap Shear ◽  
Reinforced Thermoplastics

In recent years, carbon fibre reinforced thermoplastics (CFRTP) are expected to be used as lightweight structural materials for mass-produced vehicles. CFRTP with thermoplastics as matrix allows us to weld them using melting of matrix by heating. We have been developing a direct resistance heating method, which uses carbon fibres as the resistance heating element. Carbon nanotube (CNT) is expected to be used as additive to FRP and we reported that the fibre/matrix interfacial shear strength was improved by grafting CNT on the surface of carbon fibres and tensile lap-shear strength was improved by using CNT grafted carbon fibre as the heating element for welding. For the practical use of CFRTP for structural parts, flexural strength is also necessary to be evaluated. In this study, flexural test was carried out to clarify the effect of CNT deposition time to the surface of carbon fibres on flexural strength of resistance welded CFRTP using CNT grafted carbon fibre as the heating element. The highest flexural strength was obtained when CNT10, for which CNT is grafted on the carbon fibres for deposition time of 10 min, was used for the heating element of resistance welding. In the case of CNT deposition time of 60 min, the lowest flexural strength was obtained because of the poor impregnation of the resin into the carbon fibre due to the excess CNT on the carbon fibres.

Features of the structure of carbon fibres used as filler for carbon-fibre-reinforced plastics

2010 ◽  
Vol 42 (3) ◽  
pp. 171-174
Author(s):  
E. G. Belyakova ◽  
B. S. Kogan ◽  
V. G. Pushin ◽  
N. V. Nikolaeva
Keyword(s):  
Carbon Fibre ◽  
Carbon Fibres ◽  
Reinforced Plastics ◽  
Carbon Fibre Reinforced Plastics
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