实际应用推动辐射防护体系的不断完善

本文在简要回顾国际放射防护委员会（ＩＣＲＰ）历史的基础上，首先指出在伴随着核辐射和核能的应用不断发展的同时，由ＩＣＲＰ基本建议书推荐的辐射防护体系也在实际应用中不断完善和改进。接着简要介绍了目前倍受关心的两个实际问题及其有关初步建议。文中再次强调了ＩＣＲＰ的几个重要基本观点，以及与此相悖的“打擦边球”和“零危险”两种偏面看法。最后指出，我们应该在借鉴国际经验的同时，认真总结自己的经验，为全世界共同的辐射防护事业作出我们应有的贡献。     

Integrated tolerance optimisation with simulated annealing

Tolerance is one of the most important parameters in design and manufacturing. The allocation of design and machining tolerances has a significant impact on manufacturing cost and product quality. This article presents an analytical model for simultaneously allocating design and machining tolerances based on the least-manufacturing-cost criterion. In this study, tolerance allocation is formulated as a non-linear optimisation model based on the cost-tolerance relationship. A new global optimisation algorithm, simulated annealing, is employed to solve the non-linear programming problem. An example for illustrating the optimisation model and the solution procedure is provided.     

Efficiency and optimization of an annular fin with combined heat and mass transfer – An analytical solution

An analysis was carried out to study the efficiency of annular fin when subjected to simultaneous heat and mass transfer mechanisms. The temperature and humidity ratio differences are the driving forces for the heat and mass transfer, respectively. Analytical solutions are obtained for the temperature distribution over the fin surface when the fin is fully wet. The effect of the atmospheric pressure on the fin efficiency was also studied, in addition to fin optimum dimensions. It is demonstrated that the closed-form solutions for a dry-fin case presented in many text books are special cases for the solutions presented in this paper.     

Efficient combinator code

Some combinatory logics are examined as object code for functional programs. The worst-case performances of certain algorithms for abstracting variables from combinatory expressions are analysed. A lower bound on the performance of any abstraction algorithm for a finite set of combinators is given. Using the combinators S, K, I, B, C, S′, B′, C′ and Y, the problem of finding an optimal abstraction algorithm is shown to be NP-complete. Some methods of improving abstraction algorithms for those combinators are examined, including “balancing” (for asymptotic performance) and “peephole” optimisations (for smaller cases).     

CESAR-SIRE: advanced software for boiler efficiency and NOx optimisation

The present article describes the main aspects of the fundamental research carried out to evaluate and develop the most appropriate computer tools needed to help coal power plant operators to improve heat rates and limit NO_x emissions. Work has specially focused on: (i) Analysis and experimentation of new systems for characterising and monitoring the operation of boilers; (ii) Use of cutting-edge mathematical algorithms and development of new computer tools finally implemented into the optimisation system; (iii) Development of a brand new philosophy behind the modelling process.The system is currently installed at Compostilla Power Station, belonging to ENDESA. Thanks to the recommendations of this novel approach, heat rate has been reduced over 1% and NO_x emissions over 30%.     

Evaluation of the objective functions to improve production history matching performance based on fluid flow behaviour in reservoirs

This work deals with the problem of model performance evaluation, which is a challenge in many science branches, including subsurface fluid flow modelling (e.g. reservoir characterisation using history matching algorithms).The issue is posed as a problem of estimating the model performance by comparing the simulation results with observed data. This is accomplished by defining different statistical indicator objective functions (OF) to calculate the model efficiency, i.e. how model simulation fits observed data.Several deviation-based statistics used in literature as OF are analysed and applied to two synthetic case studies related to fluid flow in reservoir. Inaccuracies that arise from using the deviation-based statistics are discussed in a comparative way to propose an appropriate approach to boost the model accuracy when selecting the best realisation from multiple equally realisations generated during the history matching algorithm.The evaluations reveal that the suitable approach requires the adoption of an OF, that combines lag time with deviation-based statistic (SSR), to enhance the history matching process. The proposed approach has proven robust in the sense that it is able to provide an accurate and faster history matching algorithm for reservoir characterisation.     

Travel Time Reliability in Vehicle Routing and Scheduling with Time Windows

This paper presents calibration of the Vehicle Routing and scheduling Problems with Time Windows-Probabilistic (VRPTW-P) model which takes into account the uncertainty of travel times. Probe vehicle data of travel times were obtained from usual operation of pickup-delivery trucks in South Osaka area. The optimal solution of the VRPTW-P model resulted in reducing total cost, running times and CO₂, NOx and Particle Materials (PM) emissions compared with the usual operation. This is attributed to better routing of VRPTW-P to choose more reliable roads. Therefore, VRPTW-P can contribute to establish efficient and environmentally friendly delivery systems in urban area.     

Optimisation of a vehicle energy absorbing steel component with experimental validation

The paper deals with the optimisation of a tapered tubular steel component to be used as an energy-absorbing device in the front structure of a vehicle body. Aim of the optimisation problem is the minimisation of a load uniformity parameter evaluated as the ratio between the maximum and the average crushing loads. The optimisation problem takes into account two design variables describing a tapered geometrical configuration, the diameter of the component at one of its bounds and the tapering length. Two improved geometrical configurations have been found and have been experimentally tested to verify the numerical results with impact velocities up to 10 m/s.     

Use of a kaolinitic clay as a pozzolanic material for cements: Formulation of blended cement

Local kaolinitic clay (from the region of Tabarka, Tunisia) was tested as a pozzolanic material. Thermal treatments were performed as a means of activation of the minerals. The phase identification, before and after heat treatment, was studied by X-ray diffraction and differential thermal analysis/thermogravimetric analysis (DTA/TGA).

In order to check the effect of three variables (the calcination temperature, the specific surface of the calcined clay and the percentage of incorporation of the heat treated clay in the formula of the blended cement) on the compressive strength of blended cement mortar bars at 7, 28 and 91 days, a Box–Behnken design was set up. It was concluded that the mechanical properties of the blended cements were mainly governed by the percentage of incorporation and the fineness of the calcined clay. It was also demonstrated that increasing the fineness of the calcined clay allowed for increases in the level of cement substitution. Finally, a blended cement composition has been formulated, with optimal results at calcining temperature 700 °C, 30% of calcined clay ground at a Blaine fineness of 7700 cm²/g.     

An efficient evolutionary optimisation framework applied to turbine blade firtree root local profiles

In this paper, an efficient evolutionary optimisation of a turbine blade firtree root local profile is presented. The firtree geometry is designed using an intelligent rule-based computer-aided design system (ICAD) and analysed using an industrial-strength finite element code. A large number of geometric and mechanical constraints drawn from past experience are incorporated in the design of the model. The high computational cost associated with finding optimal designs using high-fidelity codes is addressed using a surrogate-assisted genetic algorithm. The initial surrogate model is first built based on points sampled with a design-of-experiment method. A database of designs analysed using the high-fidelity code is built and augmented while the genetic algorithm progresses. In the procedure for deciding whether the high-fidelity code should be run, a simple 3 principle is used instead of searching for the point with maximum expected improvement. This is combined with an appropriate ranking of the design points within the database. Some benchmark test problems are first used to illustrate the effectiveness and efficiency of the framework. When applied to the problem of local shape optimisation of a turbine blade firtree root, significant improvement is achieved using a limited computational budget.