Seismic Deformation of Bar Mat Mechanically Stabilized Earth Walls. II: A Multiblock Model

A relatively simple rigid plastic multiblock computational model has been developed to predict the permanent seismic displacement of mechanically stabilized earth (MSE) walls. The model formulation was based on many observations made from a series of centrifuge tests carried out on many different configurations of MSE walls. The proposed model is similar to the sliding block method of Newmark. The approach accounted for the variation in acceleration within the backfill and the nonuniform nature of the permanent wall face deformation. The predictive capability of the proposed model has been verified using centrifuge test results obtained for four MSE walls each subjected to three earthquake excitations with strength varying between 0.48 and 0.9g. The analytical model captures many aspects of the characteristic deformation behavior of MSE walls observed in the centrifuge tests. In each of the eleven wall displacement cases studied, the backfill friction angle that yielded a good match between the computed and measured maximum wall displacement was consistent with the corresponding laboratory measured values.     

A multi-variate heart disease optimization and recognition framework

Neural Computing and Applications - Cardiovascular diseases (CVD) are the most widely spread diseases all over the world among the common chronic diseases. CVD represents one of the main causes of...     

Polyester condensation adducts as novel photo stabilizers for polystyrene

Polycondensation adducts formed by the reaction of maleic anhydride with some Polyalcohols, namely, phloroglucinol, glycerol, and ethylene glycol, were prepared, characterized, and investigated as photostabilizers for polystyrene. Their Photostabilizing effectiveness was evaluated by measuring the extent of weight loss (%), the amount of gel formed as well as the viscosity average molecular weight of the soluble fractions of the degraded polymer. The results indicated better stabilizing effects of these stabilizers compared with that of the UV absorber, phenyl salicylate. A synergistic effect was achieved when the investigated photostabilizers were mixed with phenyl salicylate in a weight ratio of 1 : 1, and a radical mechanism is proposed to account for the action of the polycondensation adducts as photostabilizers. J. VINYL ADDIT. TECHNOL., 19:293–301, 2013. © 2013 Society of Plastics Engineers     

GENERATION OF GENERALIZED MAGNETOTHERMOELASTIC WAVES BY THERMAL SHOCK IN A PERFECTLY CONDUCTING HALF-SPACE

The problem of distribution of thermal stresses and temperature is considered in a perfectly conducting half-space, in contact with a vacuum, permeated by an initial magnetic field when the bounding plane is suddenly heated to a constant temperature. The problem is in the context of generalized magnetothermoelasticity with one relaxation time. The solution is obtained using the method of potentials. Laplace transform techniques are used to derive the solution in the Laplace transform domain. The inversion process is carried out using asymptotic expansions valid for small values of time. Numerical computations for the temperature and stress distributions are carried out and represented graphically. A comparison is made with the results obtained in the absence of a magnetic field.     

Exact prediction intervals for future exponential lifetime based on random generalized order statistics

In this paper we develop two pivotal quantities to construct exact predication intervals for future exponential lifetime based on a random number of lower generalized order statistics. The distribution functions of the two pivotal quantities, when the sample size is assumed to be integer-valued random variable, are derived. Three important special cases for the random sample size are presented. A simulation study is conducted for illustrative purposes.     

Photo- and bio-degradation of poly(ester-urethane)s films based on poly[(R)-3-Hydroxybutyrate] and poly(ε-Caprolactone) blocks

Biodegradable segmented poly(ester-urethane)s derived from telechelic dihydroxy-poly[(R)-3-hydroxybutyrate], acting as hard segments, and poly(ε-caprolactone)-diols, acting as soft segments, using 1,6-hexamethylene diisocyanate, as non toxic connecting agent, were synthesized. The copolymers were characterized with regard to their molecular weight by GPC and their main thermal transitions by DSC. These copolymers as well as PHB were exposed to UV-irradiation for different time intervals and the changes in the chemical structure were analyzed by FTIR spectroscopy. Under our experimental conditions, it was found that the increase of irradiation time was accompanied by increase of the proportion of the gel fraction and the decrease of the intrinsic viscosity of the soluble fraction of the investigated copolymers. The biodegradability of PHB and poly(ester-urethane) sample containing ~40 wt% PHB before and after UV-irradiation was investigated under soil burial. The results showed that the photolysis in air prior to biodegradation increased the rate of degradation.     

On the boundary integral formulation of thermo-viscoelasticity theory

A formulation of the boundary integral equation method for generalized thermo-viscoelasticity is given. Fundamental solutions of the corresponding differential equations are obtained. An outline of the implementation of the boundary element method is discussed for the solution of the above boundary equations. Special emphasis is given to the representation of the primary fields, namely, temperature and displacement.