Adjoint-based topology optimization to reduce the energy consumption of a Hall effect thruster

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rtimi Youness ◽  
Frederic Messine
Keyword(s):  
Topology Optimization ◽  
Energy Consumption ◽  
Hall Effect ◽  
Design Problem ◽  
Design Methodology ◽  
Large Scale ◽  
Material Distribution ◽  
Original Design ◽  
Content Type ◽  
Hall Effect Thruster

Purpose The presented study aims to minimize the energy consumed by a Hall effect thruster (HET) under a constraint which makes it possible to generate a specified magnetic field in a target region of the thruster. Design/methodology/approach Herein topology optimization (TO) is used to reduce the energy consumption of an HET while keeping its performance unchanged. The design variables are the current densities in the coils and the distribution of materials in the polar pieces of the thruster. Intermediate values of material distribution are penalized using the solid isotropic material with penalization method to favor binary solutions. By means of the adjoint method, this paper provides the derivatives of the objective and constraint functions with respect to material distribution and current density variables. Findings The TO-based design methodology is developed and validated on a design example involving 2,051 variables. The approach shows its interest and its effectiveness of on a large scale two-criteria problem. Research limitations/implications In this paper, TO is presented as a tool that has allowed to explore new and innovative designs. However, although the design presented is original, its fabrication is not feasible. Despite this, the designs found give a good idea of the starting points for shape and parametric optimization tools. Practical implications Through the HET design problem, TO shows the ability to explore more original design possibilities of a complex magnetostatic design problem and to discover designs that make a HET more efficient with respect to several criteria at the same time. Originality/value A new way to reduce the energy consumption of a HET is presented. To achieve this, an adjoint-based TO method is developed and then implemented in a simple way. This approach shows that, for efficiency purposes, TO is a key tool for extending the state of the art of HET designs.

An implementation of adjoint-based topology optimization in magnetostatics

2019 ◽  
Vol 38 (3) ◽  
pp. 1023-1035 ◽  
Author(s):  
Rtimi Youness ◽  
Frederic Messine
Keyword(s):  
Topology Optimization ◽  
Finite Difference ◽  
Finite Difference Method ◽  
Difference Method ◽  
Design Problem ◽  
Large Scale ◽  
Adjoint Method ◽  
Processing Unit ◽  
Original Design ◽  
Content Type

Purpose In magnetostatics, topology optimization (TO) addresses the problem of finding the distributions of both current densities and ferromagnetic materials to comply with fixed magnetic specifications. The purpose of this paper is to develop TO in order to design Hall-effect Thrusters (HETs). Design/methodology/approach In fact, TO problems are known to be large-scale optimization problems. The authors therefore adopt the adjoint method to reduce the computation time required to obtain the gradient information. In this paper, they illustrate the continuous variant of the adjoint method in the context of magnetostatics TO. Herein, the authors propose an implementation of the adjoint method then use it within a gradient-based optimization solver fmincon-MATLAB to solve a HET TO design problem. Findings By comparison with finite difference method, the authors validate the accuracy of the suggested implementation of the adjoint method. Then, they solve a large-scale HET TO design problem. The resultant design of TO is distinctly original and not intuitive. Research limitations/implications In this paper, the authors introduce TO as a tool that has allowed them to explore new and innovative design of a HET. However, although the design presented is original, its manufacture is not feasible. Thus, a discussion section has been included at the end of paper to suggest a possible way to concretize topological solutions. Practical implications TO helps to explore more original design possibilities. In this paper, the authors present an implementation of the adjoint method that makes it possible to solve efficiently and in less central processing unit time large-scale TO design problem. Originality/value An easy implementation of the adjoint method is presented in magnetostatics TO. This implementation was first validated by comparison with the finite difference method and then used to solve a large-scale design problem. The result of the TO design problem is distinctly original and non-intuitive.

How “The Three Rules” guide strategy and investment decisions at Deloitte Consulting LLP

2015 ◽  
Vol 43 (3) ◽  
pp. 7-14 ◽  
Author(s):  
Jim Moffatt
Keyword(s):  
Design Methodology ◽  
Large Scale ◽  
Investment Decisions ◽  
Decision Makers ◽  
Research Project ◽  
Content Type ◽  
First Case ◽  
Practical Implications ◽  
Thought Leadership

Purpose – This case example looks at how Deloitte Consulting applies the Three Rules synthesized by Michael Raynor and Mumtaz Ahmed based on their large-scale research project that identified patterns in the way exceptional companies think. Design/methodology/approach – The Three Rules concept is a key piece of Deloitte Consulting’s thought leadership program. So how are the three rules helping the organization perform? Now that research has shown how exceptional companies think, CEO Jim Moffatt could address the question, “Does Deloitte think like an exceptional company?” Findings – Deloitte has had success with an approach that promotes a bias towards non-price value over price and revenue over costs. Practical implications – It’s critical that all decision makers in an organization understand how decisions that are consistent with the three rules have contributed to past success as well as how they can apply the rules to difficult challenges they face today. Originality/value – This is the first case study written from a CEO’s perspective that looks at how the Three Rules approach of Michael Raynor and Mumtaz Ahmed can foster a firm’s growth and exceptional performance.

Generative design and analysis of a double-wishbone suspension assembly: a methodology for developing constraint oriented solutions for optimum material distribution

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Aayush Bhat ◽  
Vyom Gupta ◽  
Savitoj Singh Aulakh ◽  
Renold S. Elsen
Keyword(s):  
Design Methodology ◽  
Manufacturing Industry ◽  
Optimization Technique ◽  
Design Solution ◽  
Material Distribution ◽  
Generative Design ◽  
Trade Off ◽  
Content Type ◽  
Life Study ◽  
Optimal Material

Purpose The purpose of this paper is to implement the generative design as an optimization technique to achieve a reasonable trade-off between weight and reliability for the control arm plate of a double-wishbone suspension assembly of a Formula Student race car. Design/methodology/approach The generative design methodology is applied to develop a low-weight design alternative to a standard control arm plate design. A static stress simulation and a fatigue life study are developed to assess the response of the plate against the loading criteria and to ensure that the plate sustains the theoretically determined number of loading cycles. Findings The approach implemented provides a justifiable outcome for a weight-factor of safety trade-off. In addition to optimal material distribution, the generative design methodology provides several design outcomes, for different materials and fabrication techniques. This enables the selection of the best possible outcome for several structural requirements. Research limitations/implications This technique can be used for applications with pre-defined constraints, such as packaging and loading, usually observed in load-bearing components developed in the automotive and aerospace sectors of the manufacturing industry. Practical implications Using this technique can provide an alternative design solution to long periods spent in the design phase, because of its ability to generate several possible outcomes in just a fraction of time. Originality/value The proposed research provides a means of developing optimized designs and provides techniques in which the design developed and chosen can be structurally analyzed.

Design and optimization of heating, cooling and lightening systems for a residential villa at Saman city, Iran

2019 ◽  
Vol 17 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Javad Riahi Zaniani ◽  
Shahab Taghipour Ghahfarokhi ◽  
Mehdi Jahangiri ◽  
Akbar Alidadi Shamsabadi
Keyword(s):  
Energy Consumption ◽  
Light Intensity ◽  
Design Methodology ◽  
Climatic Conditions ◽  
Content Type ◽  
Design And Optimization ◽  
Simulation Results ◽  
Annual Reduction ◽  
Reduction Of Energy Consumption ◽  
Heating Loads

Purpose This paper, using energy softwares, designed of Iran and optimized a residential villa in Saman city located in Chaharmahal and Bakhtiari Province. Design/methodology/approach Having used the ideas of Climate Consultant software, the basic designing was conducted by Design Builder Software, and the cooling and heating loads and lighting tools and equipment were calculated. Then, the amount of consuming of heating, cooling and lighting load of the building was optimized through insulation of walls and ceiling, using green roof, double glazing UPVC windows, light intensity sensor and variable refrigerant flow (VRF) system. Findings Simulation results for the stated scenarios showed an annual reduction in energy consumption of 21.1, 7.9, 26.41, 27.3 and 72.3 per cent, respectively. Also, by combining all the five scenarios, an optimal state was achieved which, from the results, brought about an annual reduction of 86.9 per cent in the energy consumption. Originality/value The authors hope that the results of the current paper could be helpful for designers and engineers in reduction of energy consumption for designing a building in similar climatic conditions.

Demystifying performance difference between local and foreign contractors through organisational culture

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chipozya Kosta Tembo ◽  
Franco Muleya ◽  
Emmanuellie Phiri
Keyword(s):  
Construction Industry ◽  
Construction Projects ◽  
Design Methodology ◽  
Large Scale ◽  
Overall Response Rate ◽  
Organisational Culture ◽  
Management Style ◽  
Content Type ◽  
Public Projects ◽  
Grade One

PurposeThis research aimed to investigate the extent to which organisational culture is practised in local and foreign contractors in grade one and two categories and how it affects their performance.Design/methodology/approachThe approach for this research was positivist in nature adopting a mono-method of data collection through a survey using self-administered questionnaires. A total of 138 questionnaires were distributed among public clients and large-scale contractors registered in the stated grades, and 112 questionnaires were returned for analysis representing an overall response rate of 81% for contractors and clients.FindingsFindings revealed that in organisational culture, significant differences were found for management style and dominant characteristics of the organisation between local and foreign contractors. Differences were not found for leadership styles, measures of success and organisational glue. Results suggest that for local contractors to perform better, significant changes are needed to their management style and dominant characteristics of their organisations.Originality/valueForeign contractors in the Zambian construction industry are reportedly outperforming local contractors making them preferred contractors on larger public projects accounting for 85% of construction projects by value of works. This study presents the differences in organisational culture between foreign and local firms. It further demonstrates that organisational culture plays a key role in determining performance of a contracting firm. The study presents areas that local contractors can improve in organisational culture in order to remain competitive.

Effects of the actively morphing root chord and taper on helicopter energy

2019 ◽  
Vol 92 (2) ◽  
pp. 264-270
Author(s):  
Firat Sal
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Flight Control ◽  
Design Methodology ◽  
Chord Length ◽  
Flight Control System ◽  
Content Type ◽  
Helicopter Blade ◽  
Blade Root ◽  
Practical Implications

Purpose The purpose of this paper presents the effects of actively morphing root chord and taper on the energy of the flight control system (i.e. FCS). Design/methodology/approach Via regarding previously mentioned purposes, sophisticated and realistic helicopter models are benefitted to examine the energy of the FCS. Findings Helicopters having actively morphing blade root chord length and blade taper consume less control energy than the ones having one of or any of passively morphing blade root chord length and blade taper. Practical implications Actively morphing blade root chord length and blade taper can be used for cheaper helicopter operations. Originality/value The main originality of this paper is applying active morphing strategy on helicopter blade root chord and blade taper. In this paper, it is also found that using active morphing strategy on helicopter blade root chord and blade taper reasons less energy consumption than using either passively morphing blade root chord length plus blade taper or not any. This causes also less fuel consumption and green environment.

Resource misallocation of SMEs in Vietnamese manufacturing sector

2019 ◽  
Vol 26 (3) ◽  
pp. 290-303
Author(s):  
Phuong Thi Nguyen ◽  
Minh Khac Nguyen
Keyword(s):  
Developing Countries ◽  
Total Factor Productivity ◽  
Design Methodology ◽  
Large Scale ◽  
Manufacturing Sector ◽  
Factor Productivity ◽  
Content Type ◽  
Resource Misallocation ◽  
Productivity Decomposition ◽  
Enterprise Survey

Purpose The purpose of this paper is to examine resource misallocation among Vietnam’s small- and medium-sized enterprises (SMEs) in the manufacturing sector. The paper also aims to consider selective factors on reducing the level of resource misallocation in SMEs. Design/methodology/approach Resource misallocation and efficiency gains in total factor productivity (TFP) are assessed using Vietnam’s annual enterprise survey data for the period 2000–2015 and an appropriate productivity decomposition framework. Findings Resource misallocation is found to be higher among SMEs than large scale enterprises. TFP is found to 116.3 per cent greater if there is no resource misallocation among SMEs. Smaller scale, lower market concentration, trade liberalisation and corruption control are found to be associated with lower level of resource misallocation in SMEs. Research limitations/implications The major limitation of this study is that it has only decomposed misallocation of resources arising from output and capital distortions and that it focusses on selective factors contribution to reducing misallocation level in SMEs. Originality/value Resource misallocation is attracting attention in both developed and developing countries. However, knowledge about resource misallocation among SMEs is limited, particularly in the context of developing countries. This paper assesses the level of resource misallocation among SMEs in Vietnamese manufacturing sector.

scholarly journals Narratives of everyday resilience: lessons from an urban kampung community in Surabaya, Indonesia

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shirleyana ◽  
Scott Hawken ◽  
Riza Yosia Sunindijo ◽  
David Sanderson
Keyword(s):  
Inner City ◽  
Design Methodology ◽  
Large Scale ◽  
Small Scale ◽  
Content Type ◽  
Disadvantaged Communities ◽  
Political Network ◽  
Starting Point ◽  
Resilience Factors ◽  
Depth Interviews

Purpose This paper aims to discuss what people perceive as risks and resilience factors, and how they build everyday resilience. Design/methodology/approach The study focuses on Kampung (literally “village”) Plampitan, a neighbourhood in the inner-city part of Surabaya. The research used field observation, in-depth interviews and workshops during community meetings to collect data. Findings The results show how people respond to daily risks and find the support necessary to survive. The problems and risks revealed in the study include crime and economic difficulties, such as unemployment and insufficient income. Coping strategies identified are classified into place-based adaption, people-based network and political network. These strategies can serve as a starting point for local communities to assess their resilience and assist them in enhancing “everyday” resilience. Originality/value The paper argues that the concept of resilience must go beyond top-down approaches to disaster risk management and integrate bottom-up understanding from the perspective of local people, especially among marginal and disadvantaged communities. The paper develops the emerging and overlooked concept of “everyday resilience” and suggests that it is essential in surviving both “everyday” or small-scale chronic risks and large-scale disasters.

scholarly journals Out to explore the cybersecurity planet

2020 ◽  
Vol 21 (2) ◽  
pp. 291-307
Author(s):  
Giampaolo Bella
Keyword(s):  
Design Methodology ◽  
Large Scale ◽  
Human Factor ◽  
Human Behaviour ◽  
Current Understanding ◽  
Content Type ◽  
Technical Systems ◽  
Security Ceremonies ◽  
Beautiful City

PurposeSecurity ceremonies still fail despite decades of efforts by researchers and practitioners. Attacks are often a cunning amalgam of exploits for technical systems and of forms of human behaviour. For example, this is the case with the recent news headline of a large-scale attack against Electrum Bitcoin wallets, which manages to spread a malicious update of the wallet app. The author therefore sets out to look at things through a different lens.Design/methodology/approachThe author makes the (metaphorical) hypothesis that humans arrived on Earth along with security ceremonies from a very far planet, the Cybersecurity planet. The author’s hypothesis continues, in that studying (by huge telescopes) the surface of Cybersecurity in combination with the logical projection on that surface of what happens on Earth is beneficial for us earthlings.FindingsThe author has spotted four cities so far on the remote planet. Democratic City features security ceremonies that allow humans to follow personal paths of practice and, for example, make errors or be driven by emotions. By contrast, security ceremonies in Dictatorial City compel to comply, hence humans here behave like programmed automata. Security ceremonies in Beautiful City are so beautiful that humans just love to follow them precisely. Invisible City has security ceremonies that are not perceivable, hence humans feel like they never encounter any. Incidentally, the words “democratic” and “dictatorial” are used without any political connotation.Originality/valueA key argument the author shall develop is that all cities but Democratic City address the human factor, albeit in different ways. In the light of these findings, the author will also discuss security ceremonies of our planet, such as WhatsApp Web login and flight boarding, and explore room for improving them based upon the current understanding of Cybersecurity.

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