Interdiffusion and adhesion at the inteface of a polystyrene-poly(2,6-dimethyl-1,4-phenylene oxide) blend below the glass transition temperature

Experiments on adhesion between the film surfaces of a polystyrene (PS)-poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) blend were carried out below the glass transition temperature of the bulk (T _g ), at T=T _g −13 and T=T _g −23°C. The contact time varied from 2 to 1440 min. The strength at the interface was then measured at room temperature. The strength at the blend-blend interface was calculated using an additive diffusion model which takes into account the strength at homopolymer-homopolymer interfaces (PS-PS, PS-PPO, and PPO-PPO), surface concentration of components, and its variation with depth. A fair agreement between the calculated and measured strength was found. The results of the study support the concept of decreasing glass transition temperature near the surface of polymer glasses as compared with T _g of the bulk. Translated from Mekhanika Kompozitnykh Materialov, Vol. 35, No. 5, pp. 661–670, September–October, 1999.     

Deformational Properties of Irradiated Composite Materials Based on PET and PE

Considering the wide applicability of polymeric composite materials, heterogeneous blends of poly(ethylene terephtalate) (PET) and polyethylenes of high and low densities (HDPE and LDPE, respectively) were investigated. Rheological (the flow-behavior index), mechanical (the yield strength and the Charpy impact strength), and morphological (crystallinity and the melting temperature) properties were detected for individual blend components and different blend compositions. A radiation treatment (-rays) was applied to improve certain characteristics of the heterogeneous blends. The results of this investigation show that the radiation modification can be successfully used to improve some physical properties of the PET-based blends and to choose individual blend components, optimum irradiation conditions, and desirable blend compositions, which allows producing materials with a predictable set of mechanical properties.     

Strength and deformation characteristics of poly(ethylene terephtalate)/elastomer blends

Changes in the toughness of crystalline poly(ethylene terephtalate) upon addition of two elastomers — ethylene-propylene-diene terpolymer and ethylene-α-octene copolymer — are investigated. Blends with increasing elastomer content (up to 30 wt.%) were obtained and modified by γ-radiation up to a 300-kGy absorbed dose. The interrelation between the toughness and certain tensile characteristics (elastic modulus, yield stress, ultimate stress, elongation at break, and specific fracture energy) of the blends, with various structural features of components (crystallinity and the degree of cross-linking) and morphology of the blends, is discussed. __________ Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 4, pp. 521–534, July–August, 2008.     

On the topology of components of some Springer fibers and their relation to Kazhdan-Lusztig theory

We describe the irreducible components of Springer fibers for hook and two-row nilpotent elements of as iterated bundles of flag manifolds and Grassmannians. We then relate the topology (in particular, the intersection homology Poincaré polynomials) of the pairwise intersections of these components with the inner products of the Kazhdan-Lusztig basis elements of irreducible representations of the rational Iwahori-Hecke algebra of type A corresponding to the hook and two-row Young shapes.     

Elastic and Thermophysical Properties of Poly(Vinyl Chloride) and Chlorinated Polyethylene Blends

The results of experimental and theoretical investigations of elastic and thermophysical properties of poly(vinyl chloride) (PVC) and chlorinated polyethylene (CPE) blends are presented. Eight types of specimens with different ratios of weight contents of PVC and CPE (PVC/CPE = 100/0, 90/10, 80/20, 60/40, 40/60, 20/80, 10/90, and 0/100) were tested. The effect of blend composition on the elastic constants (tensile and shear modulus) is discussed. The data on the thermal conductivity, thermal diffusivity, and heat capacity of the blends investigated are also presented.     

Modified generalized projective synchronization of a new fractional-order hyperchaotic system and its application to secure communication

This paper presents a new fractional-order hyperchaotic system. The chaotic behaviors of this system in phase portraits are analyzed by the fractional calculus theory and computer simulations. Numerical results have revealed that hyperchaos does exist in the new fractional-order four-dimensional system with order less than 4 and the lowest order to have hyperchaos in this system is 3.664. The existence of two positive Lyapunov exponents further verifies our results. Furthermore, a novel modified generalized projective synchronization (MGPS) for the fractional-order chaotic systems is proposed based on the stability theory of the fractional-order system, where the states of the drive and response systems are asymptotically synchronized up to a desired scaling matrix. The unpredictability of the scaling factors in projective synchronization can additionally enhance the security of communication. Thus MGPS of the new fractional-order hyperchaotic system is applied to secure communication. Computer simulations are done to verify the proposed methods and the numerical results show that the obtained theoretic results are feasible and efficient.     

Fuzzy prioritized operators and their application to multiple attribute group decision making

In this paper, we investigate the triangular fuzzy multiple attribute group decision making (MAGDM) problem in which the attributes and experts are in different priority level. Motivated by the ideal of prioritized aggregation operators (R.R. Yager, Prioritized aggregation operators, International Journal of Approximate Reasoning 48 (2008) 263–274.), we develop some prioritized aggregation operators for aggregating triangular fuzzy information, and then apply them to develop some models for triangular fuzzy multiple attribute group decision making (MAGDM) problems in which the attributes and experts are in different priority level. Finally, a practical example about talent introduction is given to verify the developed approach and to demonstrate its practicality and effectiveness.     

Mechanical Properties of Polyethylene and Poly(Ethylene Terephthalate) Blends

The results of experimental investigation of mechanical properties in tension of polyethylene (PE) and poly(ethylene terephthalate) (PET) blends are reported. Seven types of specimens with PE/PET weight ratios of 100/0, 90/10, 70/30, 50/50, 30/70, 10/90, and 0/100 were examined. The data on the influence of blend composition on the yield stress, breaking stress, yield strain, and ultimate elongation are obtained. The features of the effect of PE/PET ratio on the elastic properties of the blends are discussed.     

Finite-time stability of hybrid systems with continuous and Boolean dynamics

The hybrid systems with continuous and discrete variables can be used to describe many real-world phenomena. In this paper, by generalizing the mathematical form of gene regulatory networks, a novel class of hybrid systems consisting of continuous and Boolean dynamics is investigated. Firstly, the new hybrid system is introduced in detail, and a concept of finite-time stability (FTS) for it is proposed. Next, the existence and uniqueness of solutions are proved by fixed point theory. Furthermore, based on Lyapunov functions and the semi-tensor product (STP), i.e., Cheng product, some sufficient conditions of FTS for the hybrid systems are presented. The main results are illustrated by two numerical examples.     

Ergodic and light traffic properties of a complex repairable system

A repairable system is composed of components ofI types. A component can be loaded, put on standby, queued or repaired. The repair facility is here assumed to be a queueing system of a rather general structure though interruption of repairs is not allowed. Typei components possess a lifetime distributionA _i (t) and repair time distributionB _t (t). The lifetime of componentj is exhausted with a state-dependent rate _j (t). A Markov process Z(t) with supplementary variables is built to investigate the system behaviour. An ergodic result, Theorem 1, is established under a set of conditions convenient for light traffic analysis. In Theorems 2 to 6, a light traffic limit is derived for the joint steady state distribution of supplementary variables. Applying these results, Theorems 7 to 10 derive light traffic properties of a busy period-measured random variable. Essentially, the concepts of light traffic equivalence due to Daley and Rolski (1992) and Asmussen (1992) are used. The asymptotic (light traffic) insensitivity of busy period and steady state parameters to the form ofA _i(t) [given their means and (in some cases) values of density functions for smallt], is observed under some analytic conditions.Some abbreviations & notations LHS, RHS lefthand side, righthand side - w.r.t. with respect to - (i.i.d.) r.v. (independent identically distributed) random variables - A ^c complement event - d.f., p.d.f. distribution function, probability density function - m.g.f. moment generating function - I _A indicator function of eventA - (t) =1–A(t)     

An approximation of the analytic solution of some nonlinear heat transfer in fin and 3D diffusion equations using HAM

In this article, the approximate solution of nonlinear heat diffusion and heat transfer equation are developed via homotopy analysis method (HAM). This method is a strong and easy‐to‐use analytic tool for investigating nonlinear problems, which does not need small parameters. HAM contains the auxiliary parameter ?, which provides us with a simple way to adjust and control the convergence region of solution series. By suitable choice of the auxiliary parameter ?, we can obtain reasonable solutions for large modulus. In this study, we compare HAM results, with those of homotopy perturbation method and the exact solutions. The first differential equation to be solved is a straight fin with a temperature‐dependent thermal conductivity and the second one is the two‐ and three‐dimensional unsteady diffusion problems. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010     

Robust exponential stability and stabilizability of linear parameter dependent systems with delays

The robust exponential stability and stabilizability problems are addressed in this paper for a class of linear parameter dependent systems with interval time-varying and constant delays. In this paper, restrictions on the derivative of the time-varying delay is not required which allows the time-delay to be a fast time-varying function. Based on the Lyapunov-Krasovskii theory, we derive delay-dependent exponential stability and stabilizability conditions in terms of linear matrix inequalities (LMIs) which can be solved by various available algorithms. Numerical examples are given to illustrate the effectiveness of our theoretical results.     

Semi-selfdecomposable distributions and a new class of limit theorems

Self-decomposable distributions are given as limits of normalized sums of independent random variables. We define semi-selfdecomposable distributions as limits of subsequences of normalized sums. More generally, we introduce a way of making a new class of limiting distributions derived from a class of distributions by taking the limits through subsequences of normalized sums, and define the class of semi-selfdecomposable distributions and a decreasing sequence of subclasses of it. We give two kinds of necessary and sufficient conditions for distributions belonging to those classes, one is in terms of the decomposability of random variables and another is in terms of Lévy measures. Received: 1 May 1997 / Revised version: 5 February 1998     

Smoothness equivalence properties of univariate subdivision schemes and their projection analogues

We study the following modification of a linear subdivision scheme S: let M be a surface embedded in Euclidean space, and P a smooth projection mapping onto M. Then the P-projection analogue of S is defined as T := P ◦ S. As it turns out, the smoothness of the scheme T is always at least as high as the smoothness of the underlying scheme S or the smoothness of P minus 1, whichever is lower. To prove this we use the method of proximity as introduced by Wallner et al. (Constr Approx 24(3):289–318, 2006; Comput Aided Geom Design 22(7):593–622, 2005). While smoothness equivalence results are already available for interpolatory schemes S, this is the first result that confirms smoothness equivalence properties of arbitrary order for general non-interpolatory schemes.     

Comparison of first aggregation and last aggregation in fuzzy group TOPSIS

The Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS), one of the major multi attribute decision making (MADM) techniques, ranks the alternatives according to their distances from the ideal and the negative ideal solution. In real evaluation and decision making problems, it is vital to involve several people and experts from different functional areas in decision making process. Also under many conditions, crisp data are inadequate to model real-life situations, since human judgments including preferences are often vague and cannot estimate his preference with an exact numerical value. Therefore aggregation of fuzzy concept, group decision making and TOPSIS methods that we denote “fuzzy group TOPSIS” is more practical than original TOPSIS.     

在空间W_0~(1，x)L~(P(x))(Q)及其共轭空间中的若干收敛性定理

本文证明了在空间W_0~(1,x)L~(p(x))(Q)及其共轭空间中三个收敛性定理.在附加较弱条件的情况下,给出了几乎处处收敛蕴含弱收敛,弱收敛蕴含强收敛.     

Multi-Agent Social and Organizational Modeling of Electric Power and Natural Gas Markets

Complex Adaptive Systems (CAS) can be applied to investigate large-scale socio-cognitive-technical systems. Viewing such systems from a multi-agent social and organizational perspective allows innovative computational policy analysis. Argonne National Laboratory (ANL) has taken such a perspective to produce an integrated model of the electric power and natural gas markets. This model focuses on the organizational interdependencies between these markets. These organizational interdependencies are being strained by fundamental market transformations.     

Analysis of laminated composite plates using higher-order shear deformation plate theory and node-based smoothed discrete shear gap method

This paper presents a novel finite element formulation for static, free vibration and buckling analyses of laminated composite plates. The idea relies on a combination of node-based smoothing discrete shear gap method with the higher-order shear deformation plate theory (HSDT) to give a so-called NS-DSG3 element. The higher-order shear deformation plate theory (HSDT) is introduced in the present method to remove the shear correction factors and improve the accuracy of transverse shear stresses. The formulation uses only linear approximations and its implementation into finite element programs is quite simple and efficient. The numerical examples demonstrated that the present element is free of shear locking and shows high reliability and accuracy compared to other published solutions in the literature.     

Asymptotics of Green functions and Martin boundaries for elliptic operators with periodic coefficients

We give the asymptotics at infinity of a Green function for an elliptic equation with periodic coefficients on R^d. Basic ingredients in establishing the asymptotics are an integral representation of the Green function and the saddle point method. We also completely determine the Martin compactification of R^d with respect to an elliptic equation with periodic coefficients by using the exact asymptotics at infinity of the Green function.