A modified elliptic model of anisotropy in nonlinear magnetic materials

2010 ◽  
Vol 29 (6) ◽  
pp. 1482-1492 ◽  
Author(s):  
Oszkár Bíró ◽  
Stefan Außerhofer ◽  
Kurt Preis ◽  
Yu Chen
Keyword(s):  
Design Methodology ◽  
Magnetic Field Intensity ◽  
Nonlinear Behaviour ◽  
Content Type ◽  
Steel Material ◽  
Elliptic Model ◽  
Typical Behaviour ◽  
Magnetisation Curve ◽  
Principal Directions ◽  
Good Agreement

PurposeGrain‐oriented steel has a distinctly anisotropic and nonlinear behaviour. Only in rare cases is the magnetisation curve known for directions other than the principal ones. The paper aims at providing a model to obtain these curves for any direction if those in the easy and hard directions are only given.Design/methodology/approachThe well‐known elliptic model is modified in order to correctly mimic the typical behaviour of grain‐oriented steel which is not described correctly by the original elliptic model. An additional condition is introduced to fix the angle between the flux density and magnetic field intensity.FindingsThe model is found to yield good agreement with measurements in case of a special material for which measured curves for intermediate angles are available.Research limitations/implicationsFurther research is necessary to establish whether the model is applicable to other materials.Originality/valueThe new model can be used in numerical analyses of devices comprising saturated grain‐oriented steel material if the magnetisation curves are given in the principal directions.

The main topics of research on disclosures of intangible assets: a critical review

2016 ◽  
Vol 29 (2) ◽  
pp. 323-356 ◽  
Author(s):  
Francisca Castilla-Polo ◽  
Dolores GALLARDO-VÁZQUEZ
Keyword(s):  
Intellectual Capital ◽  
Voluntary Disclosure ◽  
Design Methodology ◽  
Lessons Learned ◽  
Future Research ◽  
Intangible Asset ◽  
Content Type ◽  
Journal Citation Reports ◽  
Principal Directions ◽  
Practical Implications

Purpose – We must acknowledge the importance of intangibles in today’s economies and the controversy over the accounting and reporting of these assets. For this reason, the purpose of this paper is to synthesize the lessons learned from research to date and identify gaps in that research that would be useful to academics and practitioners. Design/methodology/approach – The literature review was conducted after an analysis of the most important academic databases in the period of 1990-2013: ABI Inform Complete, CSIS, EconLit, ISOC, Journal Citation Reports, Scopus, Emerald, Springer, and Google Scholar. Findings – The authors offer a summary of the main gaps in the literature on intellectual capital disclosures, among which the authors perceive a need for increased qualitative or explanatory research, which would allow further analysis of such decisions. Research limitations/implications – Specifically, the main problem encountered in the research on voluntary disclosure of intangibles appears to relate to the type of methodology used, which is usually quantitative or descriptive. Practical implications – Given that the principal limitations in the field of the disclosure of intangibles have been discussed, the authors conclude by indicating the principal directions for future research. Social implications – Qualitative analysis is absent in the literature the authors reviewed, and considered it fundamental to understanding this type of disclosure. In fact, the development of future lines of research could provide better-quality intangible asset reporting. Originality/value – Although there are previous studies on this topic, the authors believe that the main contribution of this study is to offer an integrated framework of existing findings concerning decisions by companies to disclose information on intangibles, a topic on which previous literature is sparse.

The estimation of the length constant of a long cooling fin by variational iteration method

2015 ◽  
Vol 25 (4) ◽  
pp. 887-891 ◽  
Author(s):  
Yan Zhang ◽  
Qiaoling Chen ◽  
Fujuan Liu ◽  
Ping Wang
Keyword(s):  
Nonlinear Equation ◽  
Nonlinear Equations ◽  
Iteration Method ◽  
Design Methodology ◽  
Variational Iteration Method ◽  
Engineering Problem ◽  
Content Type ◽  
Variational Iteration ◽  
Length Constant ◽  
Good Agreement

Purpose – The purpose of this paper is to validate the variational iteration method (VIM) is suitable for various nonlinear equations. Design/methodology/approach – The He’s VIM is applied to solve nonlinear equation which is derived from actual engineering problem. The result was compared with other method. Findings – The result obtained from VIM shows good agreement with Xu’s result which provide a solid evidence that VIM is convenient and effective for solving nonlinear equation in the engineering. Originality/value – The VIM can be extended to many academic and engineering fields for nonlinear equations solving.

Modelling dynamic characteristics of the IGBT with thermal phenomena taken into account

2017 ◽  
Vol 34 (3) ◽  
pp. 160-164 ◽  
Author(s):  
Krzysztof Górecki ◽  
Paweł Górecki
Keyword(s):  
Design Methodology ◽  
Thermal Characteristics ◽  
Thermal Inertia ◽  
Bipolar Transistors ◽  
Insulated Gate Bipolar Transistors ◽  
Switching Circuit ◽  
Content Type ◽  
Different Types ◽  
Thermal Phenomena ◽  
Good Agreement

Purpose This paper aims to propose the electrothermal dynamic model of the insulated gate bipolar transistors (IGBT) for SPICE. Design/methodology/approach The electrothermal model of this device (IGBT), which takes into account both electrical and thermal phenomena, is described. Particularly, the sub-threshold operation of this device is considered and electrical, and thermal inertia of this device is taken into account. Attention was focused on the influence of electrical and thermal inertia on waveforms of terminal voltages of the considered transistor operating in the switching circuit and on waveforms of the internal temperature of this device. Findings The correctness of the presented model is verified experimentally and a good agreement of the calculated and measured electrical and thermal characteristics of the considered device is obtained. Research limitations/implications The presented model can be used for different types of IGBT, but it is dedicated for SPICE software only. Originality/value The form of the worked out model is presented and the results of experimental verification of this model are shown.

A new effective viscosity model for nanofluids

2018 ◽  
Vol 28 (3) ◽  
pp. 571-583 ◽  
Author(s):  
Saleh Etaig ◽  
Reaz Hasan ◽  
Noel Perera
Keyword(s):  
Nusselt Number ◽  
Regression Analysis ◽  
Effective Viscosity ◽  
Design Methodology ◽  
Viscosity Model ◽  
Horizontal Pipe ◽  
Content Type ◽  
Proposed Model ◽  
Novel Model ◽  
Good Agreement

Purpose The purpose of this paper is to present a novel model for predicting the effective viscosity of nanofluids. At present, no unified model exists for the same. Design/methodology/approach The present effective viscosity model draws upon the regression analysis of carefully selected published papers covering experimental, numerical and theoretical findings. Findings Unlike some other models, this one is reliable and has a good level of accuracy. This model has been assessed in a numerical investigation using a 3D horizontal pipe, and the results are presented. Originality/value This is a new model for predicting the effective viscosity of nanofluids. The proposed model has been tested in a 3D horizontal pipe, and the predicted results for viscosity and Nusselt number show good agreement with the available data.

A semi-analytical analysis on beam-column ultimate strength with different initial deflections

2016 ◽  
Vol 13 (6) ◽  
pp. 487-493
Author(s):  
Zhongwei Li ◽  
Xiaochuan Yu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Ultimate Strength ◽  
Design Methodology ◽  
Computer Code ◽  
Element Analysis ◽  
Content Type ◽  
Beam Columns ◽  
Different Shapes ◽  
Good Agreement

Purpose A new beam-column ultimate strength calculation method has been developed and compared with nonlinear finite element analysis by ANSYS and ABAQUS. Design/methodology/approach A computer code ULTBEAM2 based on this method has been used for one and three span beam-columns with I-shaped cross-section under axial compression. Findings This paper studies the ultimate strength of beam-columns with various initial deflections of different shapes and magnitudes. Originality/value The comparison of ULTBEAM2 and finite element analysis shows good agreement for all cases with different initial deflections.

Improving the tie force method for progressive collapse design of RC frames

2018 ◽  
Vol 9 (4) ◽  
pp. 520-531 ◽  
Author(s):  
Arash Naji
Keyword(s):  
Design Methodology ◽  
Progressive Collapse ◽  
Limit State ◽  
Content Type ◽  
Catenary Action ◽  
Closed Form Solutions ◽  
Rc Frames ◽  
Orthogonal Beams ◽  
Similar Equation ◽  
Good Agreement

Purpose The purpose of this paper is to recover the deficiency of existing tie force (TF) methods by considering the decrease in section strength due to cracking and by selecting limit state of collapse according to section properties. Design/methodology/approach A substructure is selected by isolating the connected beams from the entire structure. For interior joints, the TFs in the orthogonal beams are obtained by catenary action. For corner joints, the TFs are assessed by beam action. For edge joints, however, the resistance is gained by greater of the resistance under catenary action for periphery beams and beam action for all the connecting beams in both directions. For catenary action, the TF capacities must satisfy Equation (20). On the other hand, for beam action, the TF must satisfy Equation (16), while R is calculated from Equation (17). In the case where the length of the connecting beams is similar, Equation (19) can be used. Findings Closed form solutions are available for TFs on both beam and catenary stages. Originality/value The proposed formulation makes designing more practical and convenient. However, the proposed formulation had good agreement with experimental results.

A three-layer mechanical model for the analysis of effects of pia matter on cortical folding

2019 ◽  
Vol 36 (8) ◽  
pp. 2634-2650
Author(s):  
Linlin Wang ◽  
Jianyao Yao ◽  
Huiming Ning ◽  
Liangke Wu ◽  
Dongyang Sun ◽  
...  
Keyword(s):  
White Matter ◽  
Gray Matter ◽  
Design Methodology ◽  
Volume Growth ◽  
Cortical Folding ◽  
Layer Model ◽  
Content Type ◽  
Two Layer Model ◽  
Simulation Results ◽  
Good Agreement

Purpose This paper aims to investigate the effects of the pia matter on cerebral cortical folding. Design/methodology/approach A three-layer buckling simulation model composited by the white matter, gray matter and the pia matter is adopted to analyze the effect of the pia matter on cortical folding. The volume growth of brain tissues is simulated using thermal expansion. The effects of the pia matter growth rate, thickness and stiffness on cortical folding is investigated. Findings The simulation results show that all of these three aforementioned factors of pia matter have obvious effects on cerebral cortical folding. Especially, the thickening of the pia matter may lead to cortical folding malformation such as polymicrogyria, which is in good agreement with the recent reported anatomical findings. Originality/value The three-layer model in this paper composited by the white matter, gray matter and the pia matter is different from the usually used two-layer model only composited by the white matter and gray matter. This three-layer model has successfully validated the effect of the pia matter on cerebral cortical folding. The simulation results can explain the anatomical findings very well.

LBM simulation of piezo fan in square enclosure

2019 ◽  
Vol 30 (1) ◽  
pp. 401-426 ◽  
Author(s):  
Mohammad Yaghoub Abdollahzadeh Jamalabadi
Keyword(s):  
Prandtl Number ◽  
Design Methodology ◽  
Heat Removal ◽  
Constant Wall Temperature ◽  
Content Type ◽  
Square Enclosure ◽  
Proposed Model ◽  
Prandtl Numbers ◽  
Boltzmann Method ◽  
Good Agreement

Purpose This paper aims to investigate the use of a piezo fan in an enclosure on wall heat transfer and thermal boundary layer profile in constant wall temperature situation. Design/methodology/approach The governing partial differential equations of mass, momentum and energy in addition to boundary conditions are solved by lattice Boltzmann method. The problem is solved numerically using D2Q9 population's model and Bhatnagar–Gross–Krook collision model with a code written in MATLAB. Findings The effects of Prandtl number (Pr) and the frequency of piezo fan vibrations are critically investigated on the hydrothermal characteristics of the square cavity. The mesh independency study and the validation of the proposed model are accomplished with numerical results of Ghia et al. (1982) and analytical solution of pure conduction very good agreement is found between present results and benchmark findings. Generally, with increasing beam frequency, the heat removal from heat source increased. It is found that, for all Prandtl numbers, wall Nusselt number will increase with the increase of the beam frequency. This enhancement is more intense in higher Prandtl number. Originality/value Based on these results, the use of piezo fan in an enclosure can be classified as standalone as well as heat sink integrated cooling solution.

Suitability of passive RC-network-based inductorless bridged-T as a bandpass NGD circuit

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sébastien Lalléchére ◽  
Jamel Nebhen ◽  
Yang Liu ◽  
George Chan ◽  
Glauco Fontgalland ◽  
...  
Keyword(s):  
Design Methodology ◽  
Group Delay ◽  
Center Frequency ◽  
Proof Of Concept ◽  
Content Type ◽  
Equivalent Impedance ◽  
Measurement Results ◽  
Passive Network ◽  
Modeling Theory ◽  
Good Agreement

Purpose The purpose of this paper is to study, a bridged-T topology with inductorless passive network used as a bandpass (BP) negative group delay (NGD) function. Design/methodology/approach The BP NGD topology under study is composed of an inductorless passive resistive capacitive network. The circuit analysis is elaborated from the equivalent impedance matrix. Then, the analytical model of the C-shunt bridged-T topology voltage transfer function is established. The BP NGD analysis of the considered topology is developed in function of the bridged-T parameters. The NGD properties and characterizations of the proposed topology are analytically expressed. Moreover, the relevance of the BP NGD theory is verified with the design and fabrication of surface mounted device components-based proof-of-concept (PoC). Findings From measurement results, the BP NGD network with −151 ns at the center frequency of 1 MHz over −6.6 dB attenuation is in very good agreement with the C-shunt bridged-T PoC. Originality/value This paper develops a mathematical modeling theory and measurement of a C-shunt bridged-T network circuit.

Thermohydraulics of the liquid films in rotating heat pipes

2019 ◽  
Vol 30 (6) ◽  
pp. 2861-2866 ◽  
Author(s):  
Kamel Hooman ◽  
Mohammad Reza Safaei ◽  
Hussein Togun ◽  
Mahidzal Dahari
Keyword(s):  
Film Thickness ◽  
Heat Pipe ◽  
Flow Rate ◽  
Design Methodology ◽  
Heat Pipes ◽  
Liquid Films ◽  
Practical Application ◽  
Content Type ◽  
Closed Form Solutions ◽  
Good Agreement

Purpose In this study, closed-form solutions are presented to investigate thermohydraulics of liquid films in a rotating heat pipe. The film thickness is expressed as a function of flow rate. Design/methodology/approach Further, sensitivity of both film thickness and flow rate to the length of the rotating heat pipe can now be investigated using the explicit expressions presented here. Findings To make it easier for practical application, an approximate solution is presented on top of the exact solution. Originality/value Both approximate and exact solutions are then applied to note that results are in good agreement when compared to those available in the literature.

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