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Abstract The increasing railway traffic and the environmental issue demand to find new solutions to provide energy to autonomous train (train with embedded energy sources such as diesel power supply). Using hybrid diesel train with embedded storage elements is an interesting technical solution but this kind of multisource system presents new scientific and methodology challenges. Thus, in the paper, the problematic focus on the design and the energy management of the different sources for this system. Moreover, these two fields are linked to each other. Indeed, there is a strong influence of the sizing on the energy management but the reverse is also true. The paper deals with a new optimization approach to perform the design of both the hybrid sources sizing and their energy management. The multi-sources system is represented by a power flow model and the energy management strategy is based on a frequency approach and on dynamic programming. This direct optimization problem is solved by the Sequential Quadratic Programming (SQP) algorithm. Thus, in the paper, this optimization approach is applied to a real railway study case. A comparison is made between two cases with different energy management methods. [ABSTRACT FROM AUTHOR]

In accordance with European and national guidelines for environmental efficiency in infrastructure building, the Public Works Agency of the Andalusia Regional Government has carried out several research projects in order to increase the use of recycled aggregates from construction and demolition waste in public works, whose utilization is yet under the legislation rates. As a result of these researches is has been drafted the Catalogue for pavement and construction units design, by using recycles aggregates from construction and demolition waste (CDW). This catalogue is intended to be a technical guideline for construction managers and designers in order to remove the technical barrier that still exists for the use of those products. The technical solutions that are presented in the catalogue are based in the experience or calculated considering the particular characteristics of the recycled materials. A physiochemical and mechanical characterization of those materials has been made in laboratory and its behavior has been evaluated full scale by the execution of experimental sections that have been assessed over time. [ABSTRACT FROM AUTHOR]

Purpose Static converters generate current harmonics in power grids. For numerous studies, analytical frequency modeling is preferred to carry out their harmonic modeling in the context of sizing by optimization. However, a design by optimization has to consider other constraints, e.g. modeling constraints and operating constraints. In this way, this paper aims to focus on applying an analytical frequency modeling on the sizing by optimization of an aircraft electrical power channel.Design/methodology/approach The paper aims to size a multiphysical system by optimization. In this way, the sizing of an aircraft electrical power channel by optimization has been carried out. The models of all the channel components are analytical. Specifically, the frequency model of the power electronics is based on Tran et al. (2016) and is made of equalities and inequalities. Due to this modeling choice, the optimization satisfies hundreds of constraints, such as modeling constraints and static converter operating constraints. Furthermore, transient constraints are only verified after optimization.Findings The difficulty is the modeling of the system by taking into account nonlinear implicit equations having several solutions. A solution is the addition of inequality constraints to the model to guide the implicit solving. Furthermore, this greatly helps the optimization algorithm to find the good operating mode of the static converter, at steady state. This aspect is indispensable to validate the sizing model.Research limitations/implications The number of the configurations per operating period of the static converters is defined a priori and limited.Originality/value The analytical model for the sizing is formulated as a constrained optimization problem. Its solving and the sizing by optimization are carried out by the same optimization algorithm. [ABSTRACT FROM AUTHOR]

When pavement fatigue is being calculated, a series o f assumptions are carried out which have their own degrees of uncertainty. The method for counting heavy traffic, the passing of said traffic onto equivalent axes, the fact that the fatigue law used represents the real behaviour of the pavements or whether the future evolution of traffic is going to be as predicted, are just some of the many unknowns that exist in the process. In many countries, particularly in America, where Spanish civil engineers are working more and more, we need to take reliability into account in the process, which is a sort of safety coefficient adopted in said process in order to be able to meet initial expectations. In this article the intention was to bring attention to this subject and its application. [ABSTRACT FROM AUTHOR]

This paper proposes a universal strategy for correcting limited-accuracy size estimates from a given ultrasonic technique, by using higheraccuracy size information from another technique. The more-accurate size information needed can be developed from destructive techniques, nondestructive techniques or mathematical modeling techniques. The correction can be quantitative or semi-quantitative. As examples of limited-accuracy ultrasonic sizing techniques, this paper uses echodynamic size estimates. For these example techniques, the paper illustrates correcting size estimates both in the general theoretical case and for a specific experimental case involving inclusion-stringer discontinuities. The proposed universal strategy corrections can improve results from a test beyond what would normally be physically possible. The proposed universal strategy corrections can also improve results comparisons when a single part is tested more than once using different ultrasonic setups; examples include round-robin tests as well as periodic piping, weld and vessel maintenance tests. [ABSTRACT FROM AUTHOR]

Purpose – The conventional starting point for the design of an electrical machine (or any low-frequency electromagnetic device) is known as "sizing". In this process, a simple magnetic circuit is used to estimate the main geometric parameters. This does not work for many devices, particularly where eddy currents and non-linearity dominate. The purpose of this paper is to investigate an approach using a neural network trained on a large database of existing designs as a general sizing system. Design/methodology/approach – The approach is based on a combination of a radial basis function neural network and a database of stored performances of electrical machines. The network is trained based on a set of typical performance requirements for a machines design problem. The resulting design is analyzed using finite elements to determine if the design performance is acceptable. Findings – The number of neurons in the network was varied to determine the approximation and generalization capabilities. The finite element analysis showed that the network produced initial design parameters which resulted in an appropriate performance. Research limitations/implications – The research has looked at only one class of machine. Further work is needed on a range of machines to determine how effective the approach can be. Practical implications – The approach can provide a good initial design and thus can reduce overall design time significantly. Originality/value – The paper proposes a novel, fast and effective generalized approach to sizing low frequency electromagnetic devices. [ABSTRACT FROM AUTHOR]

A methodology for the optimal parasitic-aware design of RF power amplifiers toward maximum power efficiency is presented. It is based on a template-driven simulation-based optimization approach, including the effect of all device parasitics (transistors, passives) during the sizing. The combination of expert knowledge (in the template) with a state-of-the-art evolutionary algorithm results in a highly flexible and optimal sizing methodology tailored to RF circuits. Parasitic information is obtained through interaction with device profilers. The methodology is implemented in a fully featured software tool called M-DESIGN and is applied to the optimal sizing of a two-stage Class E power amplifier for maximum efficiency. The complete sizing was obtained in less than one hour of CPU time. Moreover, the constraint templates that were used are presented and discussed. An amplifier manufactured in a commercial 0.35-μm SM2P CMOS process and sized using the proposed methodology shows a maximum value of 67% for the drain efficiency (DE) versus 66% simulated. Measurement results show that it works at 850 MHz and has a maximum output power of 30 dBm at 23 V. The power-added efficiency (PAE) is always greater than 60% for an output power above 160 mW and a maximum PAE of 66% is achieved. [ABSTRACT FROM AUTHOR]

The paper deals with the sizing of controlled converter applications, with possibly, closed control loops, by combining several tools. The approach proposes to use symbolic calculation to perform sizing times, but also numerical calculation when symbolic expressions do not exist. The sizing model is deduced from criteria on the components (control values, average values, losses, rms values, maximum values, durations, etc.). The approach is based on two development environments: Gentiane for the modelling and simulation and Eden for the optimisation. [ABSTRACT FROM AUTHOR]

The paper deals with the sizing of a flyback converter. The approach proposes to use symbolic calculation to perform sizing times, the accuracy and the number of parameters to size. So, it presents a symbolic model to size a flyback converter using optimisation techniques. Such an approach is preferred to a simulation approach thanks to the flexibility of symbolic models and their possibility to treat a great set of criteria in few seconds or minutes. The expressions of a great part of the criteria are made by an automatic symbolic process – model builders – and the others are carried out by the designer. Such a model is used in a gradient optimisation process well known for its convergence properties. From this model, a builder carries out automatically the building of a dedicated sizing tool, by automatically transforming it into an optimisation problem and by automatically giving the corresponding sizing tool with its GUI. [ABSTRACT FROM AUTHOR]

It basically costs a dollar to tell which one's right for you [ABSTRACT FROM PUBLISHER]