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Article
Publication date: 2 January 2018

Dmytro Svyetlichnyy, Michal Krzyzanowski, Robert Straka, Lukasz Lach and W. Mark Rainforth

The holistic numerical model based on cellular automata (CA) and lattice Boltzmann method (LBM) are being developed as part of an integrated modelling approach applied to…

Abstract

Purpose

The holistic numerical model based on cellular automata (CA) and lattice Boltzmann method (LBM) are being developed as part of an integrated modelling approach applied to study the interaction of different physical mechanisms in laser-assisted additive layer manufacturing (ALM) of orthopaedic implants. Several physical events occurring in sequence or simultaneously are considered in the holistic model. They include a powder bed deposition, laser energy absorption and heating of the powder bed by the moving laser beam, leading to powder melting or sintering, fluid flow in the melted pool and flow through partly or not melted material, and solidification. The purpose of this study is to develop a structure of the holistic numerical model based on CA and LBM applicable for studying the interaction of the different physical mechanisms in ALM of orthopaedic implants. The model supposed to be compatible with the earlier developed CA-based model for the generation of the powder bed.

Design/methodology/approach

The mentioned physical events are accompanied by heat transfer in solid and liquid phases including interface heat transfer at the boundaries. The sintering/melting model is being developed using LBM as an independent numerical method for hydrodynamic simulations originated from lattice gas cellular automata. It is going to be coupled with the CA-based model of powder bed generation.

Findings

The entire laser-assisted ALM process has been analysed and divided on several stages considering the relevant physical phenomena. The entire holistic model consisting of four interrelated submodels has currently been developed to a different extent. The submodels include the CA-based model of powder bed generation, the LBM-CA-based model of heat exchange and transfer, the thermal solid-liquid interface model and the mechanical solid-liquid interface model for continuous liquid flow.

Practical implications

The results obtained can be used to explain the interaction of the different physical mechanisms in ALM, which is an intensively developing field of advanced manufacturing of metal, non-metal and composite structural parts, for instance, in bio-engineering. The proposed holistic model is considered to be a part of the integrated modelling approach being developed as a numerical tool for investigation of the co-operative relationships between multiphysical phenomena occurring in sequence or simultaneously during heating of the powder bed by the moving high energy heat source, leading to selective powder sintering or melting, fluid flow in the melted pool and through partly (or not) melted material, as well as solidification. The model is compatible with the earlier developed CA-based model for the generation of the powder bed, allowing for decrease in the numerical noise.

Originality/value

The present results are original and new for the study of the complex relationships between multiphysical phenomena occurring during ALM process based on selective laser sintering or melting, including fluid flow and heat transfer, identified as crucial for obtaining the desirable properties.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 1
Type: Research Article
ISSN: 0961-5539

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Book part
Publication date: 4 February 2015

Jody Marie Bartz, Jennifer Kurth and Matthew Wangeman

Facilitating inclusive supports and services for learners with low-incidence disabilities involves collaborative teaming, understanding the benefits and challenges…

Abstract

Facilitating inclusive supports and services for learners with low-incidence disabilities involves collaborative teaming, understanding the benefits and challenges involved in delivering inclusive supports, and appreciating the diverse and unique needs of this population. In this chapter, we provide families, educators, researchers, academics, related service personnel, and other professionals with examples of models of service and support delivery. Emphasis will be on school-age learners with low-incidence disabilities. Additionally, an insider perspective of the opportunities for, as well as benefits and barriers to, successful implementation of supports and services for learners with low-incidence disabilities is presented. The chapter concludes with future directions for research.

Details

Including Learners with Low-Incidence Disabilities
Type: Book
ISBN: 978-1-78441-250-0

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Article
Publication date: 1 January 1918

The Milk (Amendment) Order, 1917, which came into force on December 31st, provides that milk shall be sold retail only by Imperial measure; that no colouring matter shall…

Abstract

The Milk (Amendment) Order, 1917, which came into force on December 31st, provides that milk shall be sold retail only by Imperial measure; that no colouring matter shall be added to milk or cream intended for sale; that no milk to which any water has been added shall knowingly be sold or offered for sale; that no person may use for the purpose of his trade any milk can or milk bottle which bears the name, trade name, trade mark, or trade device of some person other than himself or his employer, except with the consent of such person. The Order contains a new clause, in substitution for Clauses 4 and 6 of the Milk Order, 1917 (which are revoked), providing that where milk is sold wholesale by or on behalf of any person other than the producer the maximum prices chargeable shall, unless otherwise determined, pursuant to the Order, be as follows:—

Details

British Food Journal, vol. 20 no. 1
Type: Research Article
ISSN: 0007-070X

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Book part
Publication date: 5 June 2018

Jennifer Kurth, Alison Zagona, Amanda Miller and Michael Wehmeyer

This chapter provides “viewpoints” on the education of learners with extensive and pervasive support needs. That is, students who require the most support to learn, often…

Abstract

This chapter provides “viewpoints” on the education of learners with extensive and pervasive support needs. That is, students who require the most support to learn, often categorized as having intellectual disability, multiple disabilities, autism spectrum disorder, or related disabilities. The lenses through which we provide these viewpoints are historical and future-oriented; we begin with historic perspectives on the education of students with extensive and pervasive support needs, and then provide 21st century viewpoints for these learners. We interpret the notion of viewpoints in two ways: first, consistent with a viewpoint as indicating an examination of objects (in this case, practices and interventions) from a distance so as to be able to compare and judge; and, second, viewpoint as indicating our perspective on said interventions and practice.

Details

Viewpoints on Interventions for Learners with Disabilities
Type: Book
ISBN: 978-1-78743-089-1

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Book part
Publication date: 4 February 2015

Jeremy Erickson and Carol Ann Davis

In the United States, the mandate to provide access to general education curriculum standards for all learners is clear. This chapter provides an overview and a framework…

Abstract

In the United States, the mandate to provide access to general education curriculum standards for all learners is clear. This chapter provides an overview and a framework for making individualized and curriculum choices for learners with low-incidence disabilities and cognitive deficits. Topics covered include reconciling an ecological curriculum model with a standards-based framework and an expanded discussion on embedding individualized learning targets within the ongoing lessons, routines, and activities of inclusive classrooms. Carefully planned and implemented embedded instruction can provide a match between a student’s need for individualized instruction and the everyday practices of inclusive classrooms.

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Article
Publication date: 1 December 2003

B.H. Rudall

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Abstract

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Kybernetes, vol. 32 no. 9/10
Type: Research Article
ISSN: 0368-492X

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Article
Publication date: 8 July 2019

Łukasz Łach, Dmytro Svyetlichnyy and Robert Straka

A fundamental principle of materials engineering is that the microstructure of a material controls the properties. The phase transformation is an important phenomenon that…

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119

Abstract

Purpose

A fundamental principle of materials engineering is that the microstructure of a material controls the properties. The phase transformation is an important phenomenon that determines the final microstructure. Recently, many analytical and numerical methods were used for modeling of phase transformation, but some limitations can be seen in relation to the choice of the shape of growing grains, introduction of varying grain growth rate and modeling of diffusion phenomena. There are also only few comprehensive studies that combine the final microstructure with the actual conditions of its formation. Therefore, the objective of the work is a development of a new hybrid model based on lattice Boltzmann method (LBM) and cellular automata (CA) for modeling of the diffusional phase transformations. The model has a modular structure and simulates three basic phenomena: carbon diffusion, heat flow and phase transformation. The purpose of this study is to develop a model of heat flow with consideration of enthalpy of transformation as one of the most important parts of the proposed new hybrid model. This is one of the stages in the development of the complex model, and the obtained results will be used in a combined solution of heat flow and carbon diffusion during the modeling of diffusion phase transformations.

Design/methodology/approach

Different values of overheating/overcooling affect different values in the enthalpy of transformation and thus the rate of transformation. CA and LBM are used in the hybrid model in part related to heat flow. LBM is used for modeling of heat flow, while CA is used for modeling of the microstructure evolution during the phase transformation.

Findings

The use of LBM and CA in one numerical solution creates completely new possibilities for modeling of phase transformations. CA and LBM in comparison with commonly used approaches significantly simplify interface and interaction between different parts of the model, which operates in a common domain. The CA can be used practically for all possible processes that consist of nucleation and grains growth. The advantages of the LBM method can be well used for the simulation of heat flow during the transformation, which is confirmed by numerical results.

Practical implications

The developed heat flow model will be combined with the carbon diffusion model at the next stage of work, and the new complex hybrid model at the final stage will provide new solutions in numerical simulation of phase transformations and will allow comprehensive modeling of the diffusional phase transformations in many processes. Heating, annealing and cooling can be considered.

Originality/value

The paper presents the developed model of heat flow (temperature module), which is one of the main parts of the new hybrid model devoted to modeling of phase transformation. The model takes into account the enthalpy of transformation, and the connection with the model of microstructure evolution was obtained.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 1 June 1996

Harald S. Harung, Dennis P. Heaton, William W. Graff and Charles N. Alexander

Investigates higher stages of human development in some of the world’s most accomplished performers. Indicates that far more frequent experiences of a silent, expanded…

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1916

Abstract

Investigates higher stages of human development in some of the world’s most accomplished performers. Indicates that far more frequent experiences of a silent, expanded, restfully alert and non‐attached state of heightened awareness characterize those individuals who display outstanding skill and accomplishment in their action. Interprets these findings in the light of the Vedic Psychology of Maharishi Mahesh Yogi, which describes higher states of consciousness in which peak performances are all‐time phenomena rather than extraordinary happenings. There is widespread agreement that only very few individuals reach the highest stages of human development; as a consequence, there is a considerable latent human potential in organizations and society.

Details

Journal of Managerial Psychology, vol. 11 no. 4
Type: Research Article
ISSN: 0268-3946

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Article
Publication date: 27 November 2020

Fangfang Zhang, Fengyun Yan, Tijun Chen, Xiaohong Li and Zhen Wang

This paper aims to study the effect of load on the tribological behaviour of Cu-based composites, so as to obtain a suitable applied load on these composites.

Abstract

Purpose

This paper aims to study the effect of load on the tribological behaviour of Cu-based composites, so as to obtain a suitable applied load on these composites.

Design/methodology/approach

Cu-based composites were prepared by powder sintering with direct current electric current heating and tested by Universal Mechanical Test-3 with a ball-on-disk at room temperature.

Findings

The results showed that Cu-based composites are might suitable for working under low load. There is only mild damage on the surface under a load of 2 N. While it has microcracks and shows signs of cavitation at a certain depth at 20 N and 50 N. In addition, it is evident that there are three zones in the cross-section of the matrix, namely, a mechanical mixing layer, ceramic layer and substrate, respectively.

Originality/value

There are two wear mechanisms at different loads, and the evolution of worn surfaces with sliding time is also involved. Thus, the developed material can be used for light load sliding electrical contact material applications.

Details

Industrial Lubrication and Tribology, vol. 73 no. 2
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 27 March 2020

Łukasz Łach and Dmytro Svyetlichnyy

Some functional properties of engineering materials, i.e. physical, mechanical and thermal ones, depend directly on the microstructure, which is a result of processes…

Abstract

Purpose

Some functional properties of engineering materials, i.e. physical, mechanical and thermal ones, depend directly on the microstructure, which is a result of processes occurring in the material during the forming and thermomechanical processing. The proper microstructure can be obtained in many cases by the phase transformation. This phenomenon is one of the most important processes during hot forming and heat treatment. The purpose of this paper is to develop a new comprehensive hybrid model for modeling diffusion phase transformations. A problem has been divided into several tasks and is carried out on several stages. The purpose of this stage is a development of the structure of a hybrid model, development of an algorithm used in the diffusion module and one-dimensional heat flow and diffusion modeling. Generally, the processes of phase transformations are studied well enough but there are not many tools for their complex simulations. The problems of phase transformation simulation are related to the proper consideration of diffusion, movement of phase boundaries and kinetics of transformation. The proposed new model at the final stage of development will take into account the varying grain growth rate, different shape of growing grains and will allow for proper modeling of heat flow and carbon diffusion during the transformation in many processes, where heating, annealing and cooling can be considered (e.g. homogenizing and normalizing).

Design/methodology/approach

One of the most suitable methods for modeling of microstructure evolution during the phase transformation is cellular automata (CA), while lattice Boltzmann method (LBM) suits for modeling of diffusion and heat flow. Then, the proposed new hybrid model is based on CA and LBM methods and uses high performing parallel computations.

Findings

The first simulation results obtained for one-dimensional modeling confirm the correctness of interaction between LBM and CA in common numerical solution and the possibility of using these methods for modeling of phase transformations. The advantages of the LBM method can be used for the simulation of heat flow and diffusion during the transformation taking into account the results obtained from the simulations. LBM creates completely new possibilities for modeling of phase transformations in combination with CA.

Practical implications

The studies are focused on diffusion phase transformations in solid state in condition of low cooling rate (e.g. transformation of austenite into ferrite and pearlite) and during the heating and annealing (e.g. transformation of the ferrite-pearlite structure into austenite, the alignment of carbon concentration in austenite and growth of austenite grains) in carbon steels within a wide range of carbon content. The paper presents the comprehensive modeling system, which can operate with the technological processes with phase transformation during heating, annealing or cooling.

Originality/value

A brief review of the modeling of phase transformations and a description of the structure of a new CA and LBM hybrid model and its modules are presented in the paper. In the first stage of model implementation, the one-dimensional LBM model of diffusion and heat flow was developed. The examples of simulation results for several variants of modeling with different boundary conditions are shown.

Details

Engineering Computations, vol. 37 no. 8
Type: Research Article
ISSN: 0264-4401

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