Effective capacity maximization of two-way full-duplex and half-duplex relays with finite block length packets transmission

Wireless Networks - In order to satisfy the delay requirements of telecommunication systems, in this paper, we present a cooperative network with the short packet transmission in the Rayleigh...     

Synthesis and characterization of novel diimide–dinaphthols and resulting poly(urethane–imide)s

Novel diols containing imide groups were prepared via condensation of aromatic dianhydrides with 5‐amino‐1‐naphthol. The diimide–dinaphthols prepared were characterized by conventional methods and used to synthesize new poly(urethane–imide)s (PUIs). All the polymers were characterized and their physical properties, such as solubility, solution viscosity, thermal stability, and thermal behaviour were studied. The polymers obtained showed more thermal stability than typical polyurethanes because of the presence of the imide groups. Copyright © 2003 Society of Chemical Industry     

基于不同爆轰产物的格尼速度估算新方法（英）

A new method for prediction of Gurney velocity of explosives is introduced in which energy output is correlated with the heat of detonation, the number of moles of gaseous products of detonation per gram of explosive and the average molecular weight of gaseous products. It is assumed that the CHNO explosive reacts to form products composed of N2 , CO, H2O, CO2, H2,O2 and C（s） as determined by the oxygen balance of the unreacted compound. Good agreement is obtained between measured and calculated values of Gurney velocity as compared to previous correlations which assumed the reaction products to consist of N2 , H2O, CO2 and either C（s） or O2.     

Quadratic approximate dynamic programming for input‐affine systems

We consider the use of quadratic approximate value functions for stochastic control problems with input‐affine dynamics and convex stage cost and constraints. Evaluating the approximate dynamic programming policy in such cases requires the solution of an explicit convex optimization problem, such as a quadratic program, which can be carried out efficiently. We describe a simple and general method for approximate value iteration that also relies on our ability to solve convex optimization problems, in this case, typically a semidefinite program. Although we have no theoretical guarantee on the performance attained using our method, we observe that very good performance can be obtained in practice.Copyright © 2012 John Wiley & Sons, Ltd.     

油性微乳液的循环气升式反应器的流体力学和传质性能研究简

This study reports an experimental investigation on hydrodynamics and mass transfer characteristics in a 15.6x10-3 m3 external loop airlift reactor for oil-in-water micro-emulsions with oil to water volume ratio （φ） rang- ing from 3% to 7% （by volume）. For comparative purposes, experiments were also carried out with water. Increase in φ of micro-emulsion systems results in an increment in the gas holdup and a decrease in the volumetric gas-liquid oxygen transfer coefficient and liquid circulation velocity, attributed to the escalation in the viscosity of mi- cro-emulsions. The gas holdup and volumetric mass transfer coefficient for micro-emulsion systems are signifi- cantly higher than that of water system. Two correlations are developed to predict the gas holdup and oxygen trans- fer coefficient     

The Parametric Form of Z‐Number and Its Application in Z‐Number Initial Value Problem

In this paper, the parametric form of Z‐numbers is introduced and it is followed by defining arithmetic operations on them. To suggest Z‐number initial value problem (ZIVP), definition of derivative of Z‐process is necessary. For this purpose, the generalized Hukuhara differentiation and generalized differentiation are defined in details. To solve the mentioned ZIVP, the characterization theorem is proved. Finally, for more illustrations of the subject, some examples are solved and expounded.     

Applying different optimization approaches to achieve optimal configuration of a dual pressure heat recovery steam generator

The optimal design for heat recovery steam generator (HRSG) should be chosen based on technical and economic considerations. Therefore, parameters that are related to thermodynamic and economic aspects should be considered in optimization approaches. It is worth mentioning that one of the significant issues in the HRSG design is the diversity of arrangements between various components (economizer, evaporator, and superheater), which absolutely affect the HRSG performance. According to these facts, in the present article, different arrangements of a dual pressure HRSG are analyzed, and the economizer at the high‐pressure level is divided into two parts; these arrangements are optimized by applying different optimization approaches to achieve the optimal configuration. These approaches include the reduction of gas pressure drop, the reduction of generated steam cost and the consideration of both approaches as the third approach. These three approaches are also considered to perform economic and thermodynamic optimization. With regard to the limitations of optimization such as the pinch and approach point, seven different configurations are considered. First, a comprehensive model is developed for calculating thermodynamic, heat transfer, and pressure loss. To perform a thorough optimization, both thermodynamic and geometric variables as well as diversity of various arrangements is considered using genetic algorithm. The results of the optimization study show that the best arrangement is not unique, and each arrangement has different characteristics. Hence, the best arrangement for the HRSG is chosen according to the importance of the objective functions. Copyright © 2012 John Wiley & Sons, Ltd.     

Piecewise affine modeling and control of a boiler–turbine unit

In this paper, a discrete-time piecewise affine (PWA) model has been proposed for a nonlinear model of boiler–turbine unit using plant operating points. PWA model is one of the main classes of hybrid systems being equivalent to some other hybrid modeling frameworks such as mixed logical dynamical (MLD) model. In order to control the system, a model predictive control (MPC) strategy in explicit form has been used which calculates the control law as an affine function of system states. In this method, the computation of MPC is moved off-line. The off-line control law is easier to implement reducing to a look-up table in comparison with the on-line approach. Finally, the explicit model predictive control performance has been compared with the linear controller obtained using H_∞ approach. The results are illustrated by simulations. They show that the explicit MPC method has suitably improved the system performance, especially the quantity of control efforts is smaller and without saturation compared with that of H_∞ control system.