Average configuration-dependent physical properties have been evaluated for polymethylene chains bearing similarly charged ends. The polymethylene chain contains upward from 20 bonds, and the dielectric constant of the medium ranges upward from 3.5. Configuration-dependent properties evaluated were the persistence vector, average center-of-mass vector, mean-square end-to-end distance, mean-squa...

A quantum field described by the field operator ∆a = ∆+aδΣ involving a δ-like potential is considered. Mathematically, the treatment of the δ-potential is based on the theory of self-adjoint extension of the unperturbed operator ∆. We give the general expressions for the resolvent and the heat kernel of the perturbed operator ∆a. The main attention is payed to d = 2 δ-potential though d = 1 and...

providing wider variety of products often leads to higher complexity in the manufacturing and business system. finding appropriate methods and techniques to manage these difficulties is going to be an attractive topic for researchers in operations management. by adopting a qualitative approach we have investigated the product variety management in the apparel supply chain. the main contribution...

background: drugs play a strategic role as a health commodity. thus, the supply chain management of drugs is an important issue to reducing costs and thereby improving patient health. objective: this study evaluated the status of drug supply chain management and health reform in the pharmaceutical sector of teaching hospitals in ahvaz, iran. methods: this cross-sectional study was carried out i...

Rotational isomeric state theory has been used to calculate mean-square unperturbed dimensions (r2>0 and dipole moments (/~> of ethylene-vinyl chloride copolymers as a function of chemical composition, chemical sequence distribution, and stereochemical composition of the vinyl chloride sequences. As was previously found for several other copolymeric chains, (/z2> is much more sensitive to chemi...

The dynamical origin of large-scale flows in systems driven by concentrated Archimedean forces is considered. A two-dimensional model of plumes, such as those observed in thermal convection at large Rayleigh and Prandtl numbers, is introduced. From this model, we deduce the onset of mean flow as an instability of a convective state consisting of parallel vertical flow supported by buoyancy forc...