bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling process and optimization of EMC filters for power electronics applications
Authors: Gerbaud Laurent , Touré Baidy , Schanen Jean‐Luc , Carayon Jean‐Pierre 
Published: May 2012

PurposeThe frequency simulation and optimisation of electromagnetic compatibility (EMC) filter is often computation time consuming. The purpose of this paper is to propose an approach for easy and fast modelling and optimization of power electronics structures.Design/methodology/approachThe paper proposes an approach for easy and fast modelling and optimization of power electronics structures. It focuses on the EMC filter design. To achieve this task time simulation, FFT and automatic frequency modelling are combined.FindingsAn automatic frequency modelling is proposed and also gives automatically the model gradients. Therefore, the model can be used to optimize the EMC filter, but also can help in choosing its topology. Several optimization algorithms are used and compared.Research limitations/implicationsThe power electronics load is supposed to be a set of predefined harmonic sources, obtained by time simulation + FFT before the optimisation process.Practical implicationsThe frequency model allows for the rapid designing and comparing of several structures or modelling hypothesis with regard to the parasitic elements and circuit imperfections.Originality/valueThe frequency model is automatically generated, and sizing criteria on the component (e.g. inductors, capacitor) can be added in an analytical form, for example, to deal with volume or mass criteria.
TEAM problem 22 approached by a hybrid artificial life method
Authors: Coco Salvatore , Laudani Antonino , Riganti Fulginei Francesco , Salvini Alessandro 
Published: May 2012

PurposeThe purpose of this paper is to apply a hybrid algorithm based on the combination of two heuristics inspired by artificial life to the solution of optimization problems.Design/methodology/approachThe flock‐of‐starlings optimization (FSO) and the bacterial chemotaxis algorithm (BCA) were adapted to implement a hybrid and parallel algorithm: the FSO has been powerfully employed for exploring the whole space of solutions, whereas the BCA has been used to refine the FSO‐found solutions, thanks to its better performances in local search.FindingsA good solution of the 8‐th parameters version of the TEAM problem 22 is obtained by using a maximum 200 FSO steps combined with 20 BCA steps. Tests on an analytical function are presented in order to compare FSO, PSO and FSO+BCA algorithms.Practical implicationsThe development of an efficient method for the solution of optimization problems, exploiting the different characteristic of the two heuristic approaches.Originality/valueThe paper shows the combination and the interaction of stochastic methods having different exploration properties, which allows new algorithms able to produce effective solutions of multimodal optimization problems, with an acceptable computational cost, to be defined.
Application of progressive quadratic response surface method for an oscillation problem optimization
Authors: Xuan Hoa N. , Coulomb Jean‐Louis , Gerbaud Laurent , Crebier Jean‐Christophe , Rouger Nicolas 
Published: May 2012

PurposeThe purpose of this paper is to present an effective optimization strategy applied in a physical structure optimization of a semiconductor power metal oxide semiconductor field‐effect transistor (MOSFET), with an expensive integration constraint computation.Design/methodology/approachIn order to deal with inaccuracy due to inevitable numerical errors in the objective function calculation (the power losses of the power MOSFET) and in the constraint computation, the paper proposes to use the progressive quadratic response surface method (PQRSM).FindingsThe paper focuses on four aspects: the inevitable numerical errors in the power loss and the integration constraint computation; the response surface approximation (RSA) method; the PQRSM principle; and finally the comparisons of several optimization methods applied on this application problem.Originality/valueAn original optimization method, PQRSM, is proposed for reducing the oscillation problem of a semi‐analytical model. The optimization results of PQRSM have been compared with the evolution strategy (ES) algorithm, with similar results but faster computation.
ECT sensor optimization based on RSM and GA
Authors: Brandisky Kostadin , Sankowski Dominik , Banasiak Robert , Dolapchiev Ivaylo 
Published: May 2012

PurposeThe purpose of this paper is to consider the optimization of an 8‐electrode cylindrical electrical capacitance tomography (ECT) sensor. The aim is to obtain maximum uniformity and value of the sensitivity distribution of the sensor, while keeping the mutual capacitances between the electrodes above a predefined level.Design/methodology/approachThe optimization methods that have been used are response surface methodology, genetic algorithm and a combination of both.FindingsAs results, optimum dimensions for the gap, mounting pipe, shield and insulation are determined, which ensure more uniform distribution of sensitivity in the sensing area.Originality/valueThe optimization strategies used – RSM and the combined RSM+GA – make the optimization of ECT sensors feasible. The results show the effectiveness of the RSM+GA strategy which could also be used for optimization of 3D multilayer ECT sensors.
Adjoint sensitivity in PDE constrained least squares problems as a multiphysics problem
Authors: Lahaye Domenico , Mulckhuyse Wouter 
Published: May 2012

PurposeThe purpose of this paper is to provide a framework for the implementation of an adjoint sensitivity formulation for least‐squares partial differential equations constrained optimization problems exploiting a multiphysics finite elements package. The estimation of the diffusion coefficient in a Poisson‐type diffusion equation is used as an example.Design/methodology/approachThe authors derive the adjoint formulation in a continuous setting allowing to attribute to the direct and adjoint states the role of different fields to be solved for. They are one‐way coupled through the mismatch between measured and direct states acting as a source term in the adjoint equation. Having solved for the direct and adjoint state, the sensitivity of the cost function with respect to the design variables can then be obtained by a suitable post‐processing procedure. This sensitivity can then be used to efficiently solve the least‐squares problem.FindingsThe authors derived the adjoint formulation in a continuous setting allowing the direct and adjoint states to be attributed the role of different fields to be solved. They are one‐way coupled through the mismatch between measured and direct states acting as a source term in the adjoint equation. It is found that, having solved for the direct and adjoint state, the sensitivity of the cost function with respect to the design variables can then be obtained by a suitable post‐processing procedure.Research limitations/implicationsThis paper implies that modern multiphysics finite elements packages provide a flexible and extendable software environment for the experimentation with different adjoint formulations. Such tools are therefore expected to become increasingly important in solving notoriously difficult partial differential equation (PDE)‐constrained least‐squares problems. The framework also provides the possibility of experimentation with different regularization techniques (total variation and multiscale techniques for instance) to handle the ill‐posedness of the problem.Originality/valueIn this paper the adjoint sensitivity computation is casted as a multiphysics problem allowing for a flexible and extendable implementation.
Multidisciplinary optimization formulations benefits on space mapping techniques
Authors: Ben Ayed Ramzi , Brisset Stéphane 
Published: May 2012

PurposeThe purpose of this paper is to investigate the use of multidisciplinary optimization (MDO) formulations within space‐mapping techniques in order to reduce their computing time.Design/methodology/approachThe aim of this work is to quantify the interest of using MDO formulations within space mapping techniques. A comparison of three MDO formulations is carried out in a short time by using an analytical model of a safety transformer. This comparison reveals the advantage of two formulations in terms of robustness and computing time among the three MDO formulations. Then, the best formulations are investigated within output space mapping, using both analytical and FE models of the transformer.FindingsA major computing time gain equal to 5.5 is achieved using the Individual Disciplinary Feasibility formulation within the output space‐mapping technique in the case of the safety transformer.Originality/valueThe MultiDisciplinary Feasibility formulation is the common formulation used within space‐mapping technique because it is the most conventional way to perform MDO. The originality of this paper is to investigate the Individual Disciplinary Feasibility formulation within output space‐mapping technique in order to allow the parallelization of calculation and to achieve a major reduction of computing time.
Three dimensional optimal current patterns for radiofrequency ablation treatments
Authors: Vincenza Caminiti Ida Maria , Ferraioli Fabrizio , Formisano Alessandro , Martone Raffaele 
Published: May 2012

PurposeThe purpose of this paper is to propose a planning strategy for the radio frequency ablation (RFA) treatment of hepatic tumors. The goal is to give to the surgeon the opportunity of controlling the shape and the size of the treated volume and preserving the healthy tissues.Design/methodology/approachA FEM model of the human torso is built from radiographic and MRI scans of the patients, and then the RFA treatment “dynamically optimized” by controlling currents in multiple external electrodes, in such a way to drive currents in the desired regions, burning the tumor while trying to preserve healthy regions. A suitable cellular death model is considered in order to achieve an effective description of the biological modifications in the tumor volume.FindingsA numerical method to plan the RFA treatment of hepatic tumors has been defined, aiming to preserve as much as possible healthy tissues.Research limitations/implicationsThe method depends on the knowledge of inner structure and properties of the patient's torso; while the structure of tissues can be determined by TAC or MRI scans, the physiological properties are much more uncertain.Practical implicationsThe proposed approach allows optimized RFA treatments to be designed, allowing reduction of damage to healthy tissues deriving from application of the treatment.Originality/valueThe problem of optimal design of RFA treatments has been previously tackled in literature, but in this paper, dynamical optimization techniques and a cell death rate model have been included.
Preparation and characterisation of aluminium pigments encapsulated by composite layer containing organic silane acrylate resin and SiO2
Authors: Gao A.H. , Pi P.H. , Wen X.F. , Zheng D.F. , Cai Z.Q. , Cheng J. , Yang Z.R. 
Published: May 2012

PurposeThe purpose of this paper is to enhance the anticorrosion property of aluminium pigments and to improve their compatibility with polymers in coating.Design/methodology/approachAluminium pigments encapsulated by organic‐inorganic layer were prepared by hydrolysis and condensation of organic silane acrylate resin and tetraethoxy silane (TEOS) on the surface of pigments via sol‐gel method. TEOS and poly (methyl methacryalte‐n‐butyl acrylate‐vinyl triethoxysilane) (PMBV) formed in advance by co‐polymerisation of methyl methacrylate (MMA), n‐butyl acrylate (BA) and vinyl triethoxysilane (VTES) were used as precursors. The adhesion property of the aluminium pigments was measured by peel test, and the loss of silvery appearance after encapsulation and acid soaking were both evaluated by colour lightness difference (ΔL) measurement. The encapsulated aluminium pigments were further characterised by means of FTIR, SEM, TG and XPS.FindingsIt was found that PMBV‐SiO2 thin films could be formed on the surface of aluminium pigments smoothly and uniformly, and the adhesion and anticorrosion performances of encapsulated aluminium pigments were improved significantly.Research limitations/implicationsThe organic silane acrylate resin used as a precursor in the sol‐gel process could be synthesised from other aclyate monomers. In addition, the hydrolysis and condensation mechanism of organic silane acrylate resin on the surface of aluminium pigments need further studies.Practical implicationsThe method developed provided a good solution to the two problems of aluminium pigments and increased their application values.Originality/valueThe method of improving adhesion and anticorrosion properties of aluminium pigments was novel and could find numerous applications in surface coatings and adhesives.
Lignosulphonate modified ketonic resins
Authors: Kızılcan Nilgün 
Published: May 2012

PurposeThe purpose of this paper is to describe how lignosulphonate modified ketone formaldehyde resins containing functional groups such as hydroxyl, carbonyl, phenol, were produced via in situ modification of ketone/formaldehyde resins. Cyclohexanone‐formaldehyde (CF‐R), acetophenone‐formaldehyde (AF‐R) and methyl ethyl ketone‐formaldehyde (MEKFR) resins were in situ modified with lignosulphonate in the presence of sodium hydroxide. The paper reports the synthesis of lignosulphonate‐modified resins with a one step method of in situ modification of ketonic resin. The roles of the types of the ketone, lignosulphonate concentration, the solubility, molecular weight and thermal properties of the product were investigated.Design/methodology/approachKetone, formalin (37 per cent aqueous solution), lignosulphonate were mixed and 20 per cent aqueous NaOH solution was added to produce the resin.FindingsThere was improvement of the properties of the lignosulphonate modified ketonic resins produced from waste black liquor. The lignosulphonate modified ketone‐formaldehyde resins were soluble in common organic solvents.Research limitations/implicationsThe reaction mixture must be stirred continuously. Subsequently, 37 per cent formalin was added dropwise in total while refluxing. The amount of aqueous NaOH solution is limited since the formed resin may become insoluble in common organic solvents. The water was removed from MEKFR, successively by evaporating with rotary evaporator.Practical implicationsThis study provides the application of ketonic resins. The modified ketonic resins containing lignosulphonate groups may also promote the adhesive strength of a coating. The cell walls of various cell types of plants, for example, wood fibres, vessels, and tracheid, have lignin as an important constituent. It constitutes 20‐30 per cent of the weight of wood.Originality/valueLignosulphonate modified ketonic resins have been synthesized in the presence of a base catalyst. These resins have higher Tg or Tm values and molecular weight than CFR and AFR alone and also have thermoset property. Environmental and ecological concerns have increased the attention paid by the chemical industry to renewable raw materials.
Effects of preparation parameters on the morphology of chitosan‐silica hybrid hollow nanospheres
Authors: Yan E. , Wang Y. , Jing T. , Zhang D. , Wang C. , Zhang J. 
Published: May 2012

PurposeThe purpose of this paper is to investigate the effects of preparation process and amounts of starting materials on the morphology of chitosan‐silica (CS‐silica) hybrid hollow nanospheres.Design/methodology/approachA simple method coupling sol‐gel process and in situ self‐assembly was used to prepare CS‐silica nanospheres from the solution containing chitosan‐poly (acrylic acid) (CS‐PAA) nanoparticles, tetraethoxyorthosilicate (TEOS) and polyvinylpyrrolidone (PVP). The morphology of CS‐silica hybrid hollow nanospheres was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The chemical structures of CS‐PAA nanoparticles and CS‐silica nanospheres were characterised by FT‐IR spectra.FindingsThe size and morphology of CS‐silica nanospheres was largely dependent on the starting amounts of TEOS, PVP and ammonia. Moreover, the reaction time can also affect the structures of the hybrid nanospheres.Research limitations/implicationsThe dispersibility of CS‐silica nanospheres was not good enough and the conglutination was inevitable to some extent.Practical implicationsThe coupling of sol‐gel technology and in situ self‐assembly opened a new gateway for preparing other organic/inorganic composite nanoparticles. This kind of material could be used as a slow release agent for biocides in coatings/paints.Originality/valueThe hybrid CS‐silica nanospheres showed obvious hollow structures. The morphology of nanospheres can be efficaciously controlled via adjusting the starting amounts of PVP, TEOS and ammonia, and the stirring time. The obtained CS‐silica hybrid nanospheres will have potential applications in such as drug delivery and controlled release.
Electrocopolymerization of pyrrole with bis(4‐aminobutyl)polydimethylsiloxane
Authors: Ustamehmetoğlu Belkıs , Kızılcan Nilgün , Demir Ömer 
Published: May 2012

PurposeThe purpose of this paper is to synthesise the block copolymer of pyrrole (Py) with bis(4‐inobutyl)polydimethylsiloxane (DA.PDMS) by electrochemical method. The characterisation of the insoluble block copolymers, P(Py‐b‐DA.PDMS), was performed by cyclovoltammetric measurements, solid‐state conductivity and DSC measurements. The surface morphology of the copolymers was examined with scanning electron microscope (SEM).Design/methodology/approachElectropolymerisation process was performed potentiostatically and potentiodynamically. Redox behaviour of the resulting copolymer films was investigated. In‐situ spectroelectrochemical measurement was carried out on indium thin oxide (ITO) electrodes.FindingsThe ionisation potentials (Ip), electron affinity (Ea), optical band gap (Eg), peak potentials (Ep), and doping degree (y) of copolymers were calculated by using in‐situ spectroelectrochemical measurement results. The copolymers have slightly lower doping degree, band gap, Ip and Ea values than homopolymer. Copolymers had the conductivities of 10‐5 S/cm and had Tg values.Research limitations/implicationsThis study can also be focused on obtaining conductive copolymer with insulator DA.PDMS blocks on the PPy chain by one‐step polymerisation.Practical implicationsThis work provides technical information for the synthesis and characterisation of conducting block copolymer by electrochemical method.Originality/valueChange in optical and electrical properties of the P(Py‐b‐DA.PDMS) shows the role of the individual properties of the copolymer blocks. While the DSC scan of PPy showed no transition temperature, which is a characteristic property of conducting copolymers, P(Py‐b‐DA.PDMS) had Tg values. This might be due to the inclusion of the DA.PDMS blocks on the PPy chains.
Leveraging quantitative data to improve a device‐lending program
Authors: Chapman Joyce , Woodbury David 
Published: May 2012

PurposeThe purpose of this paper is to encourage administrators of device‐lending programs to leverage existing quantitative data for management purposes by integrating analysis of quantitative data into the day‐to‐day workflow.Design/methodology/approachThis is a case study of NCSU Libraries' efforts to analyze and visualize transactional data to aid in the on‐going management of a device‐lending program.FindingsAnalysis and visualization of qualitative data related to technology lending revealed patterns in lending over the course of the semester, day, and week that had previously gone unrecognized. With more concrete data about trends in wait times, capacity lending, and circulation volume, staff are now able to make more informed purchasing decisions, modify systems and workflows to better meet user needs, and begin to explore new ideas for services and staffing models.Practical implicationsThe concepts and processes described here can be replicated by other libraries that wish to leverage transactional data analysis and data visualization to aid in management of a device‐lending program.Originality/valueAlthough much literature exists on the implementation and qualitative evaluation of device‐lending programs, this paper is the first to provide librarians with ideas for leveraging analysis of transactional data to improve management of a device‐lending program.
Supporting virtual communities through disciplinary repository development
Authors: Reznik‐Zellen Rebecca , Adamick Jessica 
Published: May 2012

PurposeThis article aims to discuss the implementation of social networking tools onto existing disciplinary repository platforms – both commercial and open source – with the purpose of building enhanced disciplinary repository‐based virtual communities.Design/methodology/approachThis article is a case study. The University of Massachusetts Amherst has served as a test‐bed for two disciplinary repository‐based virtual communities, InterNano and ESENCe, both of which serve as examples for the development of features that facilitate social connections in emerging multi‐disciplinary fields. Two different approaches to the technical implementation of social networking tools onto standard disciplinary repository software platforms are described, as well as the challenges faced by each project.FindingsAlthough disciplinary repositories are not typically conceived as social spaces, disciplinary repositories can integrate social networking components to act as “knowledge brokers” for emerging disciplines of practice. The challenges of developing disciplinary repositories as virtual communities include software limitations, community integration and trust building, and identification and acquisition of relevant content in emerging and dynamic fields.Originality/valueInterNano and ESENCe represent the growing long‐tail of disciplinary repositories, about which little literature exists. This case study demonstrates the activities and challenges of developing small‐scale multi‐disciplinary disciplinary repositories into active virtual communities.
Digital image description: a review of best practices in cultural institutions
Authors: Ménard Elaine , Smithglass Margaret 
Published: May 2012

PurposeThis paper aims to present the results of the first phase of a research project aiming to develop a bilingual taxonomy for the description of digital images. The objectives of this extensive exploration were to acquire knowledge from the existing standards for image description and to assess how they can be integrated in the development of the new taxonomy.Design/methodology/approachAn evaluation of 150 resources for organizing and describing images was carried out. In the first phase, the authors examined the use of controlled vocabularies and prescribed metadata in 70 image collections held by four types of organizations (libraries, museums, image search engines and commercial web sites). The second phase focused on user‐generated tagging in 80 image‐sharing resources, including both free and fee‐based services.FindingsThe first part of the evaluation showed that each resource presented comparable information for the images or items being described. Best practices and implementation proved to be largely consistent within each of the four categories of organizations. The second part revealed two trends: in image‐upload systems, there was a virtual absence of mandated structure beyond user name and tags; and in stock photography resources, the authors encountered a hybrid of taxonomies working in combination with user tags.Originality/valueThe analysis of best practices for the organization of digital images used by indexing specialists and non‐specialists alike has been a crucial step, since it provides the basic guidelines and standards for the categories and formats of terms, and relationships to be included in the new bilingual taxonomy, which will be developed in the next phase of the research project.