Numerical study of combustion processes in afterburners

Mathematical models and numerical methods are presented for computer modeling of aeroengine afterburners. A computer code GEMCHIP is described briefly. The algorithms SIMPLER, for gas flow predictions, and DROPLET, for droplet flow calculations, are incorporated in this code. The block correction technique is adopted to facilitate convergence. The method of handling irregular shapes of combustors and flameholders is described. The predicted results for a low-bypass-ratio turbofan afterburner in the cases of gaseous combustion and multiphase spray combustion are provided and analyzed, and engineering guides for afterburner optimization are presented

Stakeholder orientation and organizational performance in an emerging market

There has been research that studies Chinese firms’ stakeholder orientation but fails to identify Chinese firms’ specific stakeholder groups. In addition, little research in this line has been conducted so far to reflect recent Chinese constitutional transition. This study seeks to fill these gaps. It extends previous studies assuming that a fixed set of stakeholders is suitable for firms in different countries context, and identifies Chinese firms’ key stakeholder groups by adopting the descriptive approach of stakeholder theory. Based on this identification, the authors further examine how these stakeholder orientations influence organizational performance and how they interact. Interviews with managers from 107 firms show that customer, employee, shareholder, supplier, and competitors are perceived as Chinese firms’ most important stakeholders; empirical studies using data collected from 307 Chinese firms reveal that orientations towards these stakeholders enhance organizational performance. Moreover, there are synergy effects existing among customer orientation, supplier orientation, and competitor orientation, and between customer orientation and competitor orientation, while shareholder orientation has significant hindering effects upon competitor orientation as a reflection of recent institutional changes taking place in China

Calculation of Lightning Transient Responses on Wind Turbine Towers

An efficient method is proposed in this paper for calculating lightning transient responses on wind turbine towers. In the proposed method, the actual tower body is simplified as a multiconductor grid in the shape of cylinder. A set of formulas are given for evaluating the circuit parameters of the branches in the multiconductor grid. On the basis of the circuit parameters, the multiconductor grid is further converted into an equivalent circuit. The circuit equation is built in frequency-domain to take into account the effect of the frequency-dependent characteristic of the resistances and inductances on lightning transients. The lightning transient responses can be obtained by using the discrete Fourier transform with exponential sampling to take the inverse transform of the frequency-domain solution of the circuit equation. A numerical example has been given for examining the applicability of the proposed method

Contracting for IT Outsourcing with Asymmetric Information

IT outsourcing allows a business to reduce the cost of IT service delivery and improve the quality of IT service by taking advantage of the service provider’s economics of scale and technical expertise. However, the successful outsourcing of IT service is hampered by lack of guidance on how to design incentive contracts to encourage performance of the service provider, especially in the presence of information asymmetry and incentive divergence. In this article, we identify and characterize two asymmetric information factors: asymmetric effort information and asymmetric capability information. Depending on whether the service provider’s effort information and capability information is symmetric or not, we consider three information scenarios and characterize optimal incentive contracts for each scenario. We also introduce the concept of information value to quantify the adverse effects of the two asymmetric information factors. The results provide theoretical support for designing incentive contracts that mitigate the adverse effects of asymmetric information, and recommend effective guidance for activities so as to reduce the degree of information asymmetry

Novel interface-selected waves and their influences on wave competitions

The topic of interface effects in wave propagation has attracted great attention due to their theoretical significance and practical importance. In this paper we study nonlinear oscillatory systems consisting of two media separated by an interface, and find a novel phenomenon: interface can select a type of waves (ISWs). Under certain well defined parameter condition, these waves propagate in two different media with same frequency and same wave number; the interface of two media is transparent to these waves. The frequency and wave number of these interface-selected waves (ISWs) are predicted explicitly. Varying parameters from this parameter set, the wave numbers of two domains become different, and the difference increases from zero continuously as the distance between the given parameters and this parameter set increases from zero. It is found that ISWs can play crucial roles in practical problems of wave competitions, e.g., ISWs can suppress spirals and antispirals