Mechanical comparison

Thermal Oxidative Stability. ABS undergoes autoxidation and the kinetic features of the oxygen consumption reaction are consistent with an autocatalytic free-radical chain mechanism. Comparisons of the rate of oxidation of ABS with that of polybutadiene and styrene—acrylonitrile copolymer indicate that the polybutadiene component is significantly more sensitive to oxidation than the thermoplastic component (31—33). Oxidation of polybutadiene under these conditions results in embrittlement of the mbber because of cross-linking such embrittlement of the elastomer in ABS results in the loss of impact resistance. Studies have also indicated that oxidation causes detachment of the grafted styrene—acrylonitrile copolymer from the elastomer which contributes to impact deterioration (34). 

Babiker A, Andersson O, Lund E, et al. Elimination of cholesterol in macrophages and endothelial cells by the sterol 27-hydroxylase mechanism. Comparison with high-density lipoprotein-mediated reverse cholesterol transport. J Biol Chem 1997 272 26253-26261. 

Ressler et al. (2002) XAS Mo02 Oxidation mechanism comparison to Mo03 + + + Propene oxidation... 

Photo-stimulated reactions of neopentyl iodide with several carhanionic nucleophiles have been studied in which inhihition experiments with the TEMPO radical trap suggest the reaction occurs via an SrnI mechanism. Comparison of 22 nucleophiles in their 5rn1 reactions with iodobenzene by Fe(II)- and photo-induction has revealed that both are enhanced by high electron-donation ability of the nucleophile. The radical anion Phl is a key intermediate. The SET reactions of perfluoroalkyl iodides have been reviewed. Flash photolysis of H2O2 was used to generate HO and 0 radicals which were reacted with a,a,a-trifluorotoluene (TFT) and 4-fluorotoluene (4FT) and the rate constants calculated. The diminished reactivity of TFT towards HO or O with respect to toluene or benzene was consistent with radical addition to the aromatic ring, whilst the reactivity of 4FT was of the same order as electron-deficient toluenes, which favour H abstraction fi-om the aliphatic side-chain. 

L. V. Lutsevich, V. I. Elokhin, A. V. Myshlyavtsev, A. G. Usov, and G. S. Yablonskii, Monte Carlo modeling of a simple catalytic reaction mechanism comparison with langmuir kinetics, J. Catal., 132 (1991) 302. 

HA competes with HX in both extraction mechanisms. Comparison of HCl extraction by ABC extractants comprising T(OD)A and ABL, DEHPA, or DNNSA [44] shows the effect of HA acidity (Fig. 9). HCl extraction through ion-pair formation at the substoichiometric region decreases with increasing acidity of HA T(OD)A + ABL > T(OD)A -I-DEHPA > T(OD)A -I- DNNSA. In the case of H bonding to the ion pair (above-stoichiometric extraction), however, weaker HAs compete better and the above-stoichiometric extraction shows the opposite sequence T(OD)A -f- DEHPA > T(OD)A - ABL. 

Chen, F., Larsen, M.B., Sanchez, C., and Wiborg, O. 2005. The 5-enantiomer of R,5-citalopram, increases inhibitor binding to the human serotonin transporter by an allosteric mechanism. Comparison with other serotonin transporter inhibitors. Eur. Neuropsychopharmacol. 15 193-198. 

D Greenwald, S Shumway, P Albear, L Gottlieb, Mechanical comparison of 10 suture materials before and a in vivo incubation , JSurgRes, 1994 56(4) 372-377. 

Table 2. Mechanical comparison between friction and Blair hoist...

Figure 1 Crude oil production by Recovery Mechanisms. Comparison Germany / USA... 

AS value fits with the expectation of an 5n1CB mechanism. Comparison of rrans-[Cr(teta)Cl2] with rrans-[Cr(cyclam)Cl2] shows steric acceleration by C-methyl substitution in line with an 5n1CB mechanism. Loss of the second CF ion from the teta complex occurs at a similar rate to loss of the first CF, and initial rates were used in the kinetic analysis of the first stage. 

Rheology is a branch of physics concerned with the time-dependent deformation of solids and the viscous flow of liquids. Rheological models can be used to illustrate the nonlinear viscoelastic response of rPET polymer concrete. These models are mechanical comparisons that demonstrate the interrelationship between the elastic and viscous response of polymers. Simple and complex models can be proposed to... 

Note The bell model To understand pulse excitation, it is helpful to consider a mechanical comparison - a bell, for exanple, does not require excitation at its resonance frequency. Instead, a short strike with a hammer (pulse excitation) is hilly sufficient. The bell takes up the energy with no specified frequency (all potential frequencies are contained) and automatically finds its own frequency plus its overtones to resonate and, thus, to sound. 

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