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Designs, Volume 2, Issue 2 (June 2018)

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Open AccessArticle On Surrogate-Based Optimization of Truly Reversible Blade Profiles for Axial Fans
Received: 15 May 2018 / Revised: 6 June 2018 / Accepted: 7 June 2018 / Published: 20 June 2018
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Abstract
Open literature offers a wide canvas of techniques for surrogate-based multi-objective optimization. The large majority of works focus on methodological and theoretical aspects and are applied to simple mathematical functions. The present work aims at defining and assessing surrogate-based techniques used in complex
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Open literature offers a wide canvas of techniques for surrogate-based multi-objective optimization. The large majority of works focus on methodological and theoretical aspects and are applied to simple mathematical functions. The present work aims at defining and assessing surrogate-based techniques used in complex optimization problems pertinent to the aerodynamics of reversible aerofoils. Specifically, it addresses the following questions: how meta-model techniques affect the results of the multi-objective optimization problem, and how these meta-models should be exploited in an optimization test-bed. The multi-objective optimization problem (MOOP) is solved using genetic optimization based on non-dominated sorting genetic algorithm (NSGA)-II. The paper explores the possibility to reduce the computational cost of multi-objective evolutionary algorithms (MOEA) using two different surrogate models (SM): a least square method (LSM), and an artificial neural network (ANN). SMs were tested in two optimization approaches with different levels of computational effort. In the end, the paper provides a critical analysis of the results obtained with the methodologies under scrutiny and the impact of SMs on MOEA. The results demonstrate how surrogate model incorporation into MOEAs influences the effectiveness of the optimization process itself, and establish a methodology for aerodynamic optimization tasks in the fan industry. Full article
(This article belongs to the Special Issue Challenges and Progress in Turbomachinery Design)
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Open AccessArticle An Underactuated Bio-Inspired Helical Swimming Microrobot Using Fuzzy-PI Controller with Novel Error Detection Method for 5-DOF Micromanipulation
Received: 8 April 2018 / Revised: 6 June 2018 / Accepted: 8 June 2018 / Published: 14 June 2018
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Abstract
The potential of microrobots to bring about revolutionary changes over micro-operation demands is increasing day to day. This paper presents a controller to provide 5 degrees of freedom for an underactuated bio-inspired helical swimming microrobot. The considered system is a helical swimming microrobot
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The potential of microrobots to bring about revolutionary changes over micro-operation demands is increasing day to day. This paper presents a controller to provide 5 degrees of freedom for an underactuated bio-inspired helical swimming microrobot. The considered system is a helical swimming microrobot with three flagella in a low Reynolds performance environment. Control of the considered system is performed to reach any desired location, roll angle and pitch angle. The proposed controlling error definition extracted from the system geometry is general for similar actuation configurations. An error detection method for multi-propulsion-unit systems is utilized for 5-DOF micromanipulation of an underactuated bio-inspired helical swimming microrobot by fuzzy-PI controller. A fuzzy-PI controller is proposed to use modified experimental data of PI controller debugging to maintain a suitable efficient control. The comparison of two other possible controllers and the proposed fuzzy-PI controller is discussed, and the performance of trajectory tracking is evaluated by simulations. Full article
(This article belongs to the Special Issue New Trends in Intelligent Control and Filter Design)
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Open AccessArticle Development of a Butterfly Wind Turbine with Mechanical Over-Speed Control System
Received: 21 May 2018 / Revised: 8 June 2018 / Accepted: 8 June 2018 / Published: 12 June 2018
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Abstract
Based on a concept of “cost reduction by large rotor and small generator”, a kind of small vertical axis wind turbine (VAWT) called a butterfly wind turbine (BWT) has been developed with rotor diameter of 7 m and five looped blades. One of
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Based on a concept of “cost reduction by large rotor and small generator”, a kind of small vertical axis wind turbine (VAWT) called a butterfly wind turbine (BWT) has been developed with rotor diameter of 7 m and five looped blades. One of the features is a mechanical system which can twist each blade of a VAWT by using the centrifugal force acting on the blades in order to prevent over-speeding of the rotor. An electric power generation system that combines the BWT utilizing the over-speed control system (OCS) with a coreless generator connected to a three-time increasing gear unit is constructed in this study. The performance of the BWT power-generation system is predicted by the blade element momentum (BEM) theory. The final goal of this research is to show the feasibility of the low-cost VAWT power generation system with the proposed OCS. From the results of a series of forcible rotation experiments of the BWT rotor that is driven by an induction motor in very low wind speed condition, it is shown that the twist movement of the blades is improved by the design of the OCS that considers the observed radial force deprived of the centrifugal force and the pre-compression of springs. In the generation experiments with the final design of the OCS, the expected twists of the blades are observed for the first time in strong natural wind speed over 18 m/s. Full article
(This article belongs to the Special Issue Challenges and Progress in Turbomachinery Design)
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Open AccessEditorial Announcing the 2018 Designs Travel Award
Received: 6 June 2018 / Accepted: 6 June 2018 / Published: 8 June 2018
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Abstract
The Designs Travel Award for 2018 has been granted to Mr. David Schmelzeisen, a PhD student from Institut für Textiltechnik (ITA), RWTH Aachen University, Aachen, Germany. [...] Full article
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Open AccessArticle Experimental Analysis of Inerter-Based Suspension Systems for Slender Structures
Received: 7 March 2018 / Revised: 29 May 2018 / Accepted: 30 May 2018 / Published: 5 June 2018
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Abstract
Earthquakes and ambient vibrations can cause serious problems for cultural heritage objects; consequently, preserving these objects against mentioned sources of vibration has received more attention in recent years. To address this problem, in this paper, inerter is used to overcome the deficiency of
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Earthquakes and ambient vibrations can cause serious problems for cultural heritage objects; consequently, preserving these objects against mentioned sources of vibration has received more attention in recent years. To address this problem, in this paper, inerter is used to overcome the deficiency of a vibration isolator in the lower frequency range and performance of this passive device is evaluated experimentally. Specifically, first, the scaled model of an actual isolator and statue is presented. This structure has been designed and manufactured based on the results of a performance test, which has been performed on a famous statue of Michelangelo Buonarroti: Pieta Rondanini. In order to improve the performance of the isolator, a ball-screw type inerter has been designed and manufactured in this research. This device is introduced to the scaled structure and its effect on the dynamic behavior of the isolator is checked using a sine sweep vibration test. The experimental tests were performed on a shaking table in the horizontal direction. Then, the effectiveness of inerters on the dynamic behavior of the isolation system is demonstrated. It is shown that the isolator equipped with the manufactured inerters has better performance in the lower frequency range. Full article
(This article belongs to the Special Issue Vibrational Systems: Control, Sensing and Energy Harvesting)
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Open AccessArticle Design and Optimization of Fuel Injection of a 50 kW Micro Turbogas
Received: 22 March 2018 / Revised: 1 May 2018 / Accepted: 16 May 2018 / Published: 18 May 2018
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Abstract
The present article deals with the design of a micro turbogas turbine suitable for on board applications, e.g., as a power generator on hybrid transit bus, characterized by a simple constructive approach. Deriving the machine layout from an existing KJ-66 aircraft model engine,
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The present article deals with the design of a micro turbogas turbine suitable for on board applications, e.g., as a power generator on hybrid transit bus, characterized by a simple constructive approach. Deriving the machine layout from an existing KJ-66 aircraft model engine, the authors propose a theoretical design of a compact, lightweight turbogas turbine, by investigating the technical possibility and limits of the proposed design. In particular, a different combustion chamber layout has been proposed, and fuel adduction channels for different swirler designs have been simulated via ANSYS Fluent in order to identify a satisfactory fuel spreading. As a result, the complete characterization of the design parameters and geometries has been performed, and a series of RANS simulations has been used in order to identify an optimal swirler configuration. Full article
(This article belongs to the Special Issue Challenges and Progress in Turbomachinery Design)
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Open AccessReview Machine Learning with Applications in Breast Cancer Diagnosis and Prognosis
Received: 2 February 2018 / Revised: 22 April 2018 / Accepted: 23 April 2018 / Published: 9 May 2018
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Abstract
Breast cancer (BC) is one of the most common cancers among women worldwide, representing the majority of new cancer cases and cancer-related deaths according to global statistics, making it a significant public health problem in today’s society. The early diagnosis of BC can
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Breast cancer (BC) is one of the most common cancers among women worldwide, representing the majority of new cancer cases and cancer-related deaths according to global statistics, making it a significant public health problem in today’s society. The early diagnosis of BC can improve the prognosis and chance of survival significantly, as it can promote timely clinical treatment to patients. Further accurate classification of benign tumours can prevent patients undergoing unnecessary treatments. Thus, the correct diagnosis of BC and classification of patients into malignant or benign groups is the subject of much research. Because of its unique advantages in critical features detection from complex BC datasets, machine learning (ML) is widely recognised as the methodology of choice in BC pattern classification and forecast modelling. In this paper, we aim to review ML techniques and their applications in BC diagnosis and prognosis. Firstly, we provide an overview of ML techniques including artificial neural networks (ANNs), support vector machines (SVMs), decision trees (DTs), and k-nearest neighbors (k-NNs). Then, we investigate their applications in BC. Our primary data is drawn from the Wisconsin breast cancer database (WBCD) which is the benchmark database for comparing the results through different algorithms. Finally, a healthcare system model of our recent work is also shown. Full article
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Open AccessArticle Parametric Study of the Behavior of Longitudinally and Transversally Prestressed Concrete under Pure Torsion
Received: 28 March 2018 / Revised: 19 April 2018 / Accepted: 20 April 2018 / Published: 24 April 2018
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Abstract
Among several analytical models to describe the behavior of reinforced concrete (RC) and longitudinally prestressed concrete (LPC) beams under torsion, the Modified Variable Angle Truss Model (MVATM) is particularly efficient to capture the behavioral states of the member until failure and agree well
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Among several analytical models to describe the behavior of reinforced concrete (RC) and longitudinally prestressed concrete (LPC) beams under torsion, the Modified Variable Angle Truss Model (MVATM) is particularly efficient to capture the behavioral states of the member until failure and agree well with experimental results. This article aims to extend the MVATM to cover transversally prestressed concrete (TPC) beams under torsion. The changes in the formulation and calculation procedure of the original VATM, in order to include the influence of transversal prestress, are presented. The extended MAVTM is then used to compute the global response of LPC and TPC beams under torsion with similar total prestress reinforcement ratios, namely the torque–twist curves. The obtained predictions are then compared and discussed. It is shown that for the ultimate loading, transversal prestress constitutes also an effective solution to improve the behavior of the beams under torsion. However, transversal prestress is less effective to delay the cracked state. Finally, it is also shown that when prestress is distributed in both longitudinal and transversal direction, the global response of the beams under torsion is further improved, namely the resistance torque and the torsional stiffness in the cracked state. Full article
(This article belongs to the Special Issue Integrated Sustainable Building Design, Construction and Operation)
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Open AccessArticle Design Optimization of Polymer Heat Exchanger for Automated Household-Scale Solar Water Pasteurizer
Received: 23 March 2018 / Revised: 16 April 2018 / Accepted: 18 April 2018 / Published: 21 April 2018
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Abstract
A promising approach to reducing the >870,000 deaths/year globally from unsafe water is flow-through solar water pasteurization systems (SWPs). Unfortunately, demonstrated systems have high capital costs, which limits access for the poor. The most expensive component of such systems is the heat exchanger
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A promising approach to reducing the >870,000 deaths/year globally from unsafe water is flow-through solar water pasteurization systems (SWPs). Unfortunately, demonstrated systems have high capital costs, which limits access for the poor. The most expensive component of such systems is the heat exchanger (HX). Thus, this study focuses on cost optimization of HX designs for flow-through SWPs using high-effectiveness polymer microchannel HXs. The theoretical foundation for the cost optimization of a polymer microchannel HX is provided, and outputs are plotted in order to provide guidelines for designers to perform HX optimizations. These plots are used in two case studies: (1) substitution of a coiled copper HX with polymer microchannel HX, and (2) design of a polymer microchannel HX for a 3-D printed collector that can fit in an arbitrary build volume. The results show that substitution of the polymer expanded HX reduced the overall expenditure for the system by a factor 50, which aids in making the system more economical. For the second case study, the results show how future system designers can optimize an HX for an arbitrary SWP geometry. The approach of distributed manufacturing using laser welding appears promising for HX for SWP. Full article
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