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An explicit expression of stress concentration factor (SCF) for a circular hole eccentrically located in a finite-width strip of orthotropic material subjected to remote tension is derived using an approximate and analytical method. The eccentricity of the hole and the ratio of the diameter to strip width are two governing geometric parameters, and their effect to the SCF is shown clearly in the expression. The formulation for the expression is consisted of two steps, first, the derivation is based on section method using balance of force and moment, respectively, second, improvement is done by empirical modification of the related coefficients based on asymptotic matching of good results obtained for some special cases. The accuracy of the final SCF expressions is adequate except the extreme case where the eccentricity of the circular hole is very large, i.e. when the hole is located very near to one side of the strip. On the other hand, when the eccentricity is taken as zero, i.e. for the simplified case of a central circular hole in a finite-width strip, the corresponding SCF expression has good accuracy. The present work is an extension of previous work for central circular hole of orthotropic material and an eccentric circular hole for isotropic material.

In this paper, the high value‐added (ultra‐low degree of polymerization [ULDP]) polyvinyl alcohol (PVA) product was successfully prepared by oxidative chain scission method with sodium hypochlorite as an oxidant. When the molar ratio of PVA to NaClO is not less than 1:1.8, the reaction is stirred for several hours (≥2 h) at a temperature not exceeding 50°C. After precipitation and washing in methanol, PVA with polymerization degree of 38–150 can be obtained after drying. The infrared spectrum (IR) and nuclear magnetic hydrogen spectrum (1H‐NMR) test proved that the product obtained by this method is indeed PVA. The results of 1H‐NMR also showed that the chain broken has no selectivity and the stereoregularity of hydroxyl group did not change significantly. Through radical quenching experiment and electron paramagnetic resonance (EPR) analysis, it is proved that OCl− is the main active oxide, ·Cl makes the oxidative chain scission process can be realized quickly, and ·OH is an indispensable factor for obtaining ULDP PVA. Under the combined action of these three, high value‐added PVA with ULDP was successfully prepared. Additionally, the sodium hypochlorite oxidized the ·OH captured by 5,5‐dimethyl‐1‐pyrroline‐n‐oxide (DMPO‐OH) to 2‐hydroxy‐5,s‐dimethyl‐1‐pyrroline‐N‐oxide (HDMPO‐OH) in an alkaline environment.

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