Cracking suppressing

Cracking suppressed by carbonaceous deposits and aromatics became predominant. This trend was enhanced by Sn and Pb. Small amounts of Q species can act as inert additives like Sn, but at higher concentrations can form coke.84 ... 

Jitcharoen, N. P. Padture, A. E. Giannakopoulos and S. Suresh, Heitzian-Crack Suppression in Ceramics with Elastic-Modulus-Graded Surfaces, 7. Am. Ceram. Soc. 81, 2301-2308 (1998). 

From a qualitative viewpoint, the decay behavior of sulfated zirconia, and in general of sulfated transition metal oxides, is quite similar to that previously described for zeolites and other solid acids. During the initial decline in olefin conversion, a sharp increase in the concentration of Cg products occurs as a consequence of cracking suppression, followed by a rapid decrease in TMP within the Cg fraction and the concomitant increase in octenes. This trend indicates that the acid sites responsible for cracking are the first to be poisoned, followed by... 

Fillers and additives are specifically added to enhance the specific performance, reduce cost, change viscosity or improve processibility of resin systems (Owens Coming, 2003). Dry fillers usually make up the largest proportion (up to 50 wt%) of a resin formulation. Commonly used fillers in pul-trusion include calcium carbonate as a volume extender, alumina silicate or clay to build corrosion resistance and electrical insulation, and alumina trihydrate for better fiame or smoke retardation and electrical arc resistance. Additives are meant to tailor specific performance or properties. These typically include initiators to influence resin curing, mould release compounds such as metallic stearates or organic phosphate ester, antimony oxide for flame retardance, pigments for coloration and agents for surface smoothness and crack suppression. 

Hertzian crack suppression in ceramics with elastic-modulus-graded surfaces, Journal of the American Ceramic Society 81, 2301-2308. 

As discussed in the section on the influence of the polymer matrix, it is the semi-brittle failure of HDPE which is believed to be responsible for its greater intolerance to the large, poorly bonded GRT particles. The increase in the ductility of the HDPE matrix on addition of the thermoplastic elastomers, then, results in significant impact improvement through crack suppression, thus rendering the matrix more tolerant of the large GRT particles. The small increase on going from non-reactive to reactive SEES may be an indication that... 

Crack suppression this is the increase in stress, because of the presence of the fibres, required for crack initiation (i.e. the increase in the first cracking stress). 

Particular attention was given to the enhancement in the first crack stress due to the glass fibre addition (Figures 8.12 and 8.18). This could be predicted on the basis of the crack suppression equation (Eq. 4.49) developed by Aveston et al. [66] by using bond strength values in the range of 1-3 MPa [46,55], the perimeter of the strand in direct contact with the matrix, and an efficiency coefficient in the range of 1/2-3/8. 

For an industrial application it is necessary to separate the response of a real crack from artifacts, and to derive information about the geometry and the location of the crack. For this purpose we have developed a filter which is sensitive to the characteristic features of a signal caused by a crack and amplifies it, whereas signals without these typical features are suppressed. In Fig. 5.1 first results obtained with such an iterative filter algorithm are shown. 

By choosing the proper correlation algorithm, it is possible to realise sensitive filters for other types of defects (e.g. corrosion). Fig. 5.2 shows an example for the suppression of signals which do not exhibit the expected defect stmcture (Two parallel white lines near upper central rim portion of Fig. 5.2). The largest improvement in SNR is obtained here by using the expression (ai ai+x /ai+yj), since for a gradiometric excitation, one expects the crack response to show two maxima (a, aj+x) with a minimum (a m) in the centre (see Fig. 5.3). 

This enables to locate both small surface cracks from 0.1 mm deep and undersurface defects with one and the same eddy-current converter. This also allows to reveal corrosion between sheets while suppressing the influence of variation of clearance between them. 

Thermal drying has been studied in conjunction with a rail shipment of ca 1200 km from North Dakota to Illinois. Oil was appHed at 6-8 L/t to suppress dust loss, and cracks around the doors in the base of the cat were sealed to prevent ignition. Stable shipment and stockpiling were then possible (31). Thermal drying may be carried out to further reduce the moisture content as requited for briquetting or for mote efficient pulverizing and combustion. 

Thermal cracking tends to deposit carbon on the catalyst surface which can be removed by steaming. Carbon deposition by this mechanism tends to occur near the entrance of the catalyst tubes before sufficient hydrogen has been produced by the reforming reactions to suppress the right hand side of the reaction. Promoters, such as potash, are used to help suppress cracking in natural gas feedstocks containing heavier hydrocarbons. Carbon may also be formed by both the disproportionation and the reduction of carbon monoxide... 

In addition to carbonates and/or phosphates, a variety of substances have also been used to act as sludge conditioners —e.g. starches, lignins, polyacrylates etc. Other substances, such as nitrites and sulphates are claimed to have some value in the suppression of caustic cracking (see Section 5.1). 

---