Subject cyclic mechanism

Refractories in rotary kilns are subject to cyclic mechanical stresses as a result of flexing of the kiln shell as it rotates. They are also exposed to greater thermal shock when the kiln is shut down or re-lit. 

Cellular Mechanotransduction in Microfluidic Systems, Fig. 7 A novel microfabricated array that is capable of subjecting cyclic equibiaxial tensile strains of different magnitude, (a) Overview of a microarray mechanical stimulator, (b) Schematic cross-sectional... 

When subjected to cyclic mechanical stresses, most materials fail at a stress level that is considerably lower than that required to cause rupture in a single stress cycle. This phenomenon is called/flh gMe. Various modes of fatigue testing in common use... 

One case in which this analysis can be usefully applied is that of the elecfio-chemically assisted (stress corrosion) cracking of metals submerged in an electrolyte and subjected to a cyclic mechanical load or stress, corresponding to vibrational... 

The diaphragms (division plates or partitions) are subjected not only to wear, but also to considerable cyclic mechanical loads. These affect more particularly the supporting frames on which the liner plates or the slotted screen plates of the diaphragms are mounted. The inevitable differential movements between these frames and the mill shell, and also between them and the plates they carry, have to... 

B. Solvolysis of Phosphoric Acid Derivatives.—Interest continues in neighbouring-group participation in the solvolysis of phosphate esters. As a potential model compound for investigating the mechanism of ribo-nuclease action, the phenyl hydrogen phosphate ester of c/j-3,4-tetrahydro-furandiol (24) has been the subject of a detailed study. Above (and probably also below) pH 4 hydrolysis gives solely the cyclic phosphate (25)... 

The fifth paper in this chapter is by S. Kochetova and N. Tumanova of the National Academy of Sciences of Ukraine. It addresses subjects of electrolysis of molten carbamides. Authors report on interesting results of their study of the mechanisms of reactions occurring in the carbamide and carbamide-chloride melts using techniques of cyclic voltammetry in combination with gas chromatography and IR spectroscopy. 

Dynamic properties are taken to mean the results from mechanical tests in which the plastic is subjected to a deformation pattern from which the cyclic stress-strain behaviour is calculated. These do not include cyclic tests in which the main objective is to fatigue the material. 

The cationic ring-opening polymerization of cyclic ethers has been the subject of many recent investigations (1.. Nuclear magnetic resonance (NMR) methods, particularly carbon-13 techniques, have been found most useful in studying the mechanism of these polymerizations ( ). In the present review we would like to report some of our recent work in this field. 

Evidence for this mechanism includes (1) an experiment showing a 4.5% nOe between and of the triene in Eq. (14), validating the -stereochemistry of the exo-cyclic olefin and (2) preparation of a hexadeuterated allenyne that was subjected to the reaction conditions which gave complete transfer of a deuterium atom to the exocyclic double bond of the triene (Eq. 15). 

For the alkali metal cations, the stability (14) and permeability (43) sequences for dicyclohexyl-18-crown-6 have been found to be the same (K+ > Rb+ > Cs+ > Na+ > Li+). Thus, a direct relationship exists between the ability of a macrocyclic compound to complex a particular cation (as measured by the log K value for complex formation) and its influence on the biological transport of that cation. Furthermore, it would appear that the biological ion-transport mechanism may in part be due to the complexation properties of the macrocyclic carrier molecules. This subject with respect to cyclic antibiotics has been treated extensively by Si wow and co-workers (2). 

The reagent most commonly used for oxidation of ethers is RuO. The subject is well summarized in an early review by Gore [75], Primary methyl ethers RCHjOCHj are oxidised to esters RCOOCH, and secondary methyl ethers R R CjHjOCHj to ketones R COR while with benzyl ethers PhCH OR the esters PhCOOR are formed. For cyclic ethers, the carbon atoms adjacent to the O atom are oxidised, and if there are two secondary carbon atoms the main products are lactones, sometimes with partial hydrolysis to carboxylic acids [75], There is a short review on oxidation of ethers by RuO, principally on the mechanisms involved [76],... 

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