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Designs, Volume 3, Issue 2 (June 2019)

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Cover Story (view full-size image) Modern homecare systems can be the key factor to ageing in place, ensuring seniors’ well-being and [...] Read more.
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Open AccessArticle
Grid Generation for CFD Analysis and Design of a Variety of Twin Screw Machines
Received: 28 May 2019 / Revised: 13 June 2019 / Accepted: 15 June 2019 / Published: 25 June 2019
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Abstract
A detailed study of the fluid flow and thermodynamic processes in positive displacement machines requires 3D CFD modeling in order to capture their real geometry, including leakage gaps. However, limitations in the conventional computational grids, used in commercial software packages, exclude their use [...] Read more.
A detailed study of the fluid flow and thermodynamic processes in positive displacement machines requires 3D CFD modeling in order to capture their real geometry, including leakage gaps. However, limitations in the conventional computational grids, used in commercial software packages, exclude their use for classical twin screw machines. The screw compressor rotor grid generator (SCORG) is a customized grid generation tool developed to overcome these limitations. This paper shows how it can be further extended to include non-conventional rotor designs, such as those with variable lead or profile variation and even internally geared machines with conical rotors. Other arrangements possible with this improvement include multiple gate rotors to increase volumetric displacement or dual lead, high wrap angle rotors for very high-pressure differences and vacuum applications. A case study of a water-injected twin screw compressor is included to demonstrate its use for both detailed flow analysis and design. Full article
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Open AccessArticle
Harmonics Mitigation Based on the Minimization of Non-Linearity Current in a Power System
Received: 16 May 2019 / Revised: 7 June 2019 / Accepted: 11 June 2019 / Published: 14 June 2019
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Abstract
Harmonic issues in power systems are becoming an important topic for industrial customers and power suppliers alike due to their adverse effects in both consumer appliances as well as for utility suppliers. Consumers should seek to reduce harmonic pollution, regardless of voltage or [...] Read more.
Harmonic issues in power systems are becoming an important topic for industrial customers and power suppliers alike due to their adverse effects in both consumer appliances as well as for utility suppliers. Consumers should seek to reduce harmonic pollution, regardless of voltage or current distortion already present in the network. This article suggests a new method for suppressing distortions by using the non-linearity current index (NLCI) to determine the shunt single-tuned passive filter (STPF) compensator value in non-sinusoidal power systems, with the objective of maintaining the power factor within desired limits. The objective of the proposed method is to minimize the nonlinear current of customer’s loads in the power system at the point of common coupling (PCC). Moreover, the proposed design takes into consideration other practical constraints for the total voltage and individual harmonic distortion limits, ensuring compliance with (Institute of Electrical and Electronics Engineers) IEEE 519-2014 guidelines, maintaining distortions at an acceptable level while also abiding by the capacitor loading constraints established in IEEE 18-2012. The performance of the optimally designed compensator is assessed using well documented IEEE standards based on numerical examples of nonlinear loads taken from previous publications. Full article
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Open AccessArticle
3D Printed Radar Lenses with Anti-Reflective Structures
Received: 1 May 2019 / Revised: 3 June 2019 / Accepted: 5 June 2019 / Published: 11 June 2019
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Abstract
Background: The purpose of this study was to determine if 3D printed lenses with wavelength specific anti-reflective (AR) surface structures would improve beam intensity and thus radar efficiency for a Printed Circuit Board (PCB)-based 60 GHz radar. This would have potential for improved [...] Read more.
Background: The purpose of this study was to determine if 3D printed lenses with wavelength specific anti-reflective (AR) surface structures would improve beam intensity and thus radar efficiency for a Printed Circuit Board (PCB)-based 60 GHz radar. This would have potential for improved low-cost radar lenses for the consumer product market. Methods: A hyperbolic lens was designed in 3D Computer Aided Design (CAD) software and was then modified with a wavelength specified AR structure. Electromagnetic computer simulation was performed on both the ‘smooth’ and ‘AR structure’ lenses and compared to actual 60 GHz radar measurements of 3D printed polylactic acid (PLA) lenses. Results: The simulation results showed an increase of 10% in signal intensity of the AR structure lens over the smooth lens. Actual measurement showed an 8% increase in signal of the AR structure lens over the smooth lens. Conclusions: Low cost and readily available Fused Filament Fabrication (FFF) 3D printing has been shown to be capable of printing an AR structure coated hyperbolic lens for millimeter wavelength radar applications. These 3D Printed AR structure lenses are effective in improving radar measurements over non-AR structure lenses. Full article
(This article belongs to the Special Issue 3D-Printed RF Devices and Antennas)
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Open AccessCommunication
Development of Graphical Interface Simulator of Advanced Wastewater Treatment Design Process for Teaching, Learning, and Assessment
Received: 27 March 2019 / Revised: 21 May 2019 / Accepted: 22 May 2019 / Published: 4 June 2019
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Abstract
This paper presents the concept of check and balance approach in teachıng, learning and assessment processes with the development of a graphical interface tool to solve an advanced wastewater treatment design problem. The developed graphical interface improves the quality of teaching, learning, and [...] Read more.
This paper presents the concept of check and balance approach in teachıng, learning and assessment processes with the development of a graphical interface tool to solve an advanced wastewater treatment design problem. The developed graphical interface improves the quality of teaching, learning, and the assessment of both, understanding the calculation approaches, as well as understanding the concepts. The tool acts as a calculator or a simulator of a unit converter, population equivalent, designing sewerage systems and selected unit processes of advanced wastewater treatment. A close-ended survey assessment was conducted with a total of 49 respondents who were the registered students for the subject of advanced wastewater treatment. About 79% of respondents agreed that it was hard to score a high mark in the advanced wastewater treatment exam. However, 100% of respondents agreed that the tool could help them to accelerate their understanding of the subject topic. All things considered, the findings of this study show that the developed tool is a potential tool that can aid in the teaching, learning, and assessment processes of any difficult subject that is taught in higher-learning institutions. Full article
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Open AccessArticle
Design of PI Fuzzy Logic Gain Scheduling Load Frequency Control in Two-Area Power Systems
Received: 19 February 2019 / Revised: 23 March 2019 / Accepted: 29 May 2019 / Published: 1 June 2019
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Abstract
In this paper the use of the proportional integral (PI) algorithm incorporated with the fuzzy logic technique has been proposed as advanced gain scheduling load frequency control (GLFC) in two-area power systems. The proposed controller comprises two-level control systems, such that it consists [...] Read more.
In this paper the use of the proportional integral (PI) algorithm incorporated with the fuzzy logic technique has been proposed as advanced gain scheduling load frequency control (GLFC) in two-area power systems. The proposed controller comprises two-level control systems, such that it consists of a pure integral compensator which is connected in parallel with a PI controller. However, and based on load demand, the PI parameters are updated online by means of fuzzy logic rules. With this control technique it becomes possible to eliminate steady state errors as well as to maintain good transient responses. The task of keeping a stable and overall satisfactory mode of operation in interconnected electric power systems is the main goal of any control strategy. This should be guaranteed over a wide range of operating conditions and particularly in sudden and drastic load changes. Therefore, the suggested approach has been examined following abnormal changes in loading conditions to clarify its reliability. The report also investigates the performance of the pure integral (I) controller and GLFC in individual configurations to highlight the advantages of the offered algorithm over the standard ones. The criterion of integral square error (ISE) has been exploited in the performance assessment for the designed controllers. Several simulation scenarios have been conducted, using the MATLAB–Simulink package, to illustrate the proficiency of the developed technique. Full article
(This article belongs to the Special Issue Artificial Intelligence Supported Design and Innovation)
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Open AccessArticle
Design of a Pixelated Imaging System for Fast Neutron Sources
Received: 18 April 2019 / Revised: 20 May 2019 / Accepted: 21 May 2019 / Published: 23 May 2019
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Abstract
Imaging detectors that use X-ray radiation and pulsed neutron sources have increased in sophistication in recent years due to the use of solid-state detectors. A key method for neutron detection is the nuclear activation of materials by neutrons. Neutron activation can generate radionuclides [...] Read more.
Imaging detectors that use X-ray radiation and pulsed neutron sources have increased in sophistication in recent years due to the use of solid-state detectors. A key method for neutron detection is the nuclear activation of materials by neutrons. Neutron activation can generate radionuclides whose decay produces secondary particle emission that can be detected without interference from the X-rays and other prompt radiation sources and offers advantages over neutrons detection using scintillators. In this paper, we present the design of an imaging system for fast neutron sources. The imaging system utilizes a microcontroller network that communicates using a modified SPI protocol. This network communicates with an interface unit and passes an image to a personal computer. A computer program has been developed to reconstruct the image. Full article
(This article belongs to the Special Issue Artificial Intelligence Supported Design and Innovation)
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Open AccessArticle
Social Media Monitoring: An Innovative Intelligent Approach
Received: 15 April 2019 / Revised: 15 May 2019 / Accepted: 16 May 2019 / Published: 20 May 2019
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Abstract
Digital marketers have a range of tools at their disposal for understanding customers and prospects on social media. These tools allow for better social media monitoring and analysis through the provision of vital insights. The use of artificial intelligence (AI) to such analysis [...] Read more.
Digital marketers have a range of tools at their disposal for understanding customers and prospects on social media. These tools allow for better social media monitoring and analysis through the provision of vital insights. The use of artificial intelligence (AI) to such analysis enables for marketing tasks automation, accuracy improvement and human efforts reduction. In this respect, this paper proposes an AI-powered social media monitoring platform, which has been designed with an innovative approach, towards enabling digital marketers to better understand customers with intelligent insights in a manner like never before. The proposed platform helps by analyzing insights for effective online reputation management and competitors monitoring. In addition, this paper elaborates on contributions in respect to social media monitoring issues, mentions analysis uncovering knowledge, smarter insights and personalized advice to help in improving brands web and social presence, negative and positive conversations, competitors analysis ensuring brands are on top of the marketing game and social media strategy improvement. Full article
(This article belongs to the Special Issue Artificial Intelligence Supported Design and Innovation)
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Open AccessArticle
Increasing Usability of Homecare Applications for Older Adults: A Case Study
Received: 26 March 2019 / Revised: 3 May 2019 / Accepted: 7 May 2019 / Published: 9 May 2019
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Abstract
As the world’s population is ageing, the field dealing with technology adoption by seniors has made headway in the scientific community. Recent technological advances have enabled the development of intelligent homecare systems that support seniors’ independent living and allow monitoring of their health [...] Read more.
As the world’s population is ageing, the field dealing with technology adoption by seniors has made headway in the scientific community. Recent technological advances have enabled the development of intelligent homecare systems that support seniors’ independent living and allow monitoring of their health status. However, despite the amount of research to understand the requirements of systems designed for the elderly, there are still unresolved usability issues that often prevent seniors from enjoying the benefits that modern ICT technologies may offer. This work presents a usability assessment of “HeartAround”, an integrated homecare solution incorporating communication functionalities, as well as health monitoring and emergency response features. An assessment with the system usability scale (SUS) method, along with in-depth interviews and qualitative analysis, has provided valuable insights for designing homecare systems for seniors, and validated some effective practical guidelines. Full article
(This article belongs to the Special Issue Artificial Intelligence Supported Design and Innovation)
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Open AccessReview
The Design of a Thermoelectric Generator and Its Medical Applications
Received: 21 March 2019 / Revised: 23 April 2019 / Accepted: 23 April 2019 / Published: 26 April 2019
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Abstract
Growing energy demands are driving people to generate power in every possible way. New energy sources are needed to plug the energy gap. There is a growing interest in distributed energy generation due to its remarkable advantages such as flexibility, reliability, adaptability and [...] Read more.
Growing energy demands are driving people to generate power in every possible way. New energy sources are needed to plug the energy gap. There is a growing interest in distributed energy generation due to its remarkable advantages such as flexibility, reliability, adaptability and minimal transmission losses. Thermoelectric generators (TEGs) are one such distributed power source that relies on thermal energy for electricity generation. The current review focusses on the design and optimization of TEGs to maximize the power output from the available thermal sources. The basic principle of thermoelectricity generation and suitable architecture for specific applications are explained with an overview of materials and manufacturing processes. Various cooling techniques to dissipate heat from the cold side and their influence on overall efficiency are reviewed in this work. Applications of TEGs for powering biomedical sensors have been discussed in detail. Recent advancements in TEGs for various implantable devices and their power requirements are evaluated. The exploitation of TEGs to generate power for wearable sensors has been presented, along with published experimental data. It is envisioned that this study will provide profound knowledge on TEG design for specific applications, which will be helpful for future endeavours. Full article
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Open AccessArticle
Establishing Flow Stress and Elongation Relationships as a Function of Microstructural Features of Ti6Al4V Alloy Processed using SLM
Received: 14 February 2019 / Revised: 10 April 2019 / Accepted: 11 April 2019 / Published: 13 April 2019
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Abstract
Selective laser melting (SLM) is an attractive technology for fabricating complex metal parts with reduced number of processing steps compared to traditional manufacturing technologies. The main challenge in its adoption is the variability in mechanical property produced through this process. Control and understanding [...] Read more.
Selective laser melting (SLM) is an attractive technology for fabricating complex metal parts with reduced number of processing steps compared to traditional manufacturing technologies. The main challenge in its adoption is the variability in mechanical property produced through this process. Control and understanding of microstructural features affected by the SLM process is the key for achieving desirable mechanical properties. Numerous studies have been published related to microstructure and mechanical properties of SLM printed parts; however, few of those reported end-to-end process–structure–property relationship. Therefore, the current study aims to comprehensively present the widespread microstructure information available on SLM processed Ti6Al4V alloy. Furthermore, its effects on the magnitude and anisotropy of the resultant mechanical properties, such as the yield strength and elongation, has been established. A Hall–Petch relationship is established between α lath size and yield strength magnitude for the as-built, heat-treated, transverse, and longitudinal built samples. The anisotropy in flow stress is established using the α lath size and prior β grain orientation. Percentage elongation was identified to be affected by both α lath size and powder layer thickness, due to its correlation with the prior β columnar grain size. A linear relationship was established between percentage elongation and combined size of α lath and powder layer thickness using the rule of mixtures. Full article
(This article belongs to the Special Issue Design and Applications of Additive Manufacturing and 3D Printing)
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Open AccessTechnical Note
Study on Protective Coal Pillar Size Design for Ultra High Voltage Line Tower Mining in Mountain Areas
Received: 13 March 2019 / Revised: 2 April 2019 / Accepted: 2 April 2019 / Published: 4 April 2019
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Abstract
High voltage line towers in mining areas are sensitive to surface deformation caused by mining. Protective coal pillar design for high voltage towers is one of the commonly-used technical measures. Aiming to solve the coal mining safety problem under the Ultra High Voltage [...] Read more.
High voltage line towers in mining areas are sensitive to surface deformation caused by mining. Protective coal pillar design for high voltage towers is one of the commonly-used technical measures. Aiming to solve the coal mining safety problem under the Ultra High Voltage transmission line in Sihe Coal Mine of Shanxi Province, the angle and size of protective coal pillars with the vertical line method were analyzed in this paper. The effect of additional displacement caused by landslide or slippage mining in mountain areas and repeated mining was considered. Based on the principle of the vertical line method, the protective coal pillar range and size were calculated. The amount of coal deposited in coal pillars for high voltage line towers was compared and analyzed between the vertical line method and the linear structure method. The results showed that the angle of critical deformation decreased by 2~10° caused by slippage due to mining in a mountainous area, and the angle in the uphill direction of building decreased more than that in the downhill direction; when multi-seams were mined repeatedly, the angle of critical deformation in the lower seam coal mining was reduced by 5~10° compared with that of the upper seam. The protective coal pillar design with the vertical line method can protect the high voltage line towers more effectively, and the amount of protective coal pillars with the vertical line method was 5.8 million tons less, which avoided the waste of coal resources. Full article
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