Detailed Design Process Research Articles

Supporting activities in public infrastructure projects that benefit most from ECI: Focus on the design sub-phase

Complex infrastructure projects have an increasing need to engage contractors in the pre-construction phase. Recent studies show that the early involvement of the contractor has a positive impact on the quality of the design, safety, cost, and time.The purpose of this study is to examine the main supporting design activities in the design-subphase in the pre-construction phase and examine which of these can benefit most from ECI. Semi-structured interviews were conducted, along with 3 workshops, literature studies, and document studies. 16 design activities were identified, and it was concluded that the top three activities that could benefit most from ECI are Constructability Reviews, Operability Reviews, and Design Reviews.Results showed an overall agreement that it would be beneficial to involve contractor competence during the late design-sub phase, more precisely during the transition from late schematic to detailed design process. Results from interviews are in contrast with the literature findings, which indicate that the early conceptual phase is most beneficial as the contractor impact is highest.

ОБЕСПЕЧЕНИЕ КАЧЕСТВА ПРОЕКТИРОВАНИЯ РЕЗИСТИВНОГО НАГРЕВАТЕЛЬНОГО КАБЕЛЯ НА ОСНОВЕ РАЗРАБОТКИ МЕТОДИКИ МАТЕМАТИЧЕСКОГО РАСЧЕТА

The article is devoted to developing a mathematical model for calculating the electrical and design parameters of a resistive heating cable. The aim of the work is to consider the main stages of designing a heating cable and to develop a methodology for calculating its main parameters and design, which will ensure the quality and performance characteristics of the future product that meets all modern technical, technological and economic requirements. The main stages of the heating cable design process are described and recommendations are given on selecting materials, calculating the electrical and design parameters, namely: rated power, electrical resistance, diameters and mass of conductors, insulation, shield and shell. Based on the electrically conductive shield design the paper examines in detail methods for calculating the weight and size parameters of shields in the form of a copper grounding conductor with foil, as well as in the form of a screening braid made of copper wires. The proposed methodology for calculating a resistive heating cable allows considering the design process in more detail. It is at this stage that the future product quality is determined, while ensuring the required characteristics and parameters, as well as reliability and consistency of the performance throughout the product entire life cycle.

Synthesis of green light olefins from direct hydrogenation of CO2. Part II: detailed process design and optimization

BackgroundIn Part II, our objective is to investigate the optimal configuration and operating conditions for each process section of the CO2-based light olefin production process described in Part I. MethodThe main sections (reaction, CO2 capture, and olefin recovery) in the entire process are rigorously designed and optimized. Six alternative reactor configurations were proposed, and optimized by maximizing the productivity. The Trade-offs between cost, indirect CO2 emission, and CO2 capture ratio were analyzed for the CO2 capture section through multi-objective optimization. Three scenarios for olefin recovery were proposed and optimized by minimizing costs. Significant findingsFor the reaction section, the configuration employing two fixed-bed reactors with co-current heat exchange (Scheme R6) results in the highest conversion (75.45 %) and selectivity towards light olefins (82.49 %). Both are significantly higher than the available data in the literature. For the CO2 capture section, the optimal configuration has a 90 % CO2 capture ratio and requires a specific energy of 3.63 GJ/Ton-CO2. For the olefin recovery section, over 50 % of the costs can be reduced if hydrogen is removed before entering the cryogenic distillation process (Scheme O1). These findings support that the entire process presented in Part I of this study is in economical and environmentally-friendly conditions.

Fundamental ray tracing project based on OpenGL with acceleration

In 3D computer graphics, ray tracing is an essential technique for modeling light transport for use in a wide variety of rendering algorithms for generating digital images. And it is also an important subject for computer science students who want to discover more in Computer Graphics and image rendering. In this project the author implemented a fundamental light tracing system based on C++ in visual studio. It is able to render a delicate image with an input of a nnf model file, and output a ppm file, as a final assignment of a student computer graphics research program. This paper is divided into two chapters. The first chapter is about some fundamental theories that are critical to light tracing. The second chapter is about detailed design and implementation process of the program. And the final chapter is about some actual problems and effective solutions.

Combining finite element and reinforcement learning methods to design superconducting coils of saturated iron-core superconducting fault current limiter in the DC power system.

A saturated iron-core type superconducting fault current limiter (SI-SFCL) can effectively restrict the magnitude of the fault current and alleviate the strain on circuit breakers in DC power systems. Design of a superconducting coil (SC), which is one of the key tasks in the SI-SFCL design, requires guaranteeing a sufficient magnetic field, ensuring optimization of the shape and size, minimizing the wire cost, and satisfying the safety and stability of operation. Generally, finite element method (FEM) is used to calculate and evaluate the operating characteristics of SCs, from which it is possible to determine their optimal design parameters. When the coil is complex and large, the simulation time may range from hours to days, and if input parameters change even slightly, the simulations have to be redone from scratch. Recent advances in deep learning represent the ability to be effective for modeling and optimizing complex problems from training data or in real-time. In this paper, we presented a combination of the FEM simulation and deep Q-network (DQN) algorithm to optimize the SC design of a lab-scale SI-SFCL for a DC power system. The detailed design process and options for the SC of SI-SFCL were proposed. In order to analyze the characteristics related to the electromagnetic properties and operational features of the SC, a 3D FEM model was developed. Then, a DQN model was constructed and integrated with the FEM simulation for training and optimizing the design parameters of the SC in real-time. The obtained results of this study have the potential to effectively optimize the design parameters of large-scale SI-SFCL development for high-voltage DC power systems.

Non-mechanical axial focus tuning by coherent beam combining technique

High-speed variable-focus optics brings new opportunity to the applications of fiber laser in the fields of advanced laser processing, laser three-dimensional (3D) printing, imaging and so on. As an emerging field, variable-z-focus optical elements have been developed rapidly. There are many approaches to achieve high-speed variable focus such as ferroelectric liquid crystal lens, acoustically driven fluid lenses and enhanced adaptive optical technologies. In this paper, a method of non-mechanical axial focus tuning by coherent beam combining (CBC) technique is investigated. The method does not depend on any made-to-order element to achieve the high-speed variable focus. We provide detailed design processes and theoretical basis of how to achieve focus tuning by CBC technique. Then, the influencing factors of the tunable range of focus are analyzed. We also propose a tilt modulation assisted method in this paper to extend the tuning range furtherly. Finally, a visual demonstration is carried out by spatial light modulators to verify the method and achieving 10 cm tuning range of focus point.

Detailing the idea of the design process of hydraulic automation objects

The work is touched to the design methods of the complex technical objects. The reason of the objects complication is the requirement of the dynamical processes coordination because the planed characteristics are needed. The main design stages idea – circuit diagram – simulation – structure are considered. The means of the design stages information representing of traditional approach are the relatively commonly and not consistent. It leads to design time increasing. In this work to structure the design information, coordinate the means of the different stage information representation with each others and detail design process are proposed. To do it the common information space of knowledge of the subject aria are separated on the streams. The streams represent information about the content, uniting, activities and requirements. The design process is represented as the transactions chain. Each transaction is based on the named streams and successively forms the state of the resulting functional stream. These states reflect the readiness levels of the designed object. Due to this way of means representation and detailing of information the coordination between different stages was provided. There are the possibilities to check the stage correctness executing also. As result the iteration reducing and time consumption of the design process are reached. The design process is illustrated by the example.

Thermal Loss Analysis, Design, and Test of a Novel HTS Magnet System for the Double-Stator Field-Modulation HTS Electrical Machine

A novel double-stator field-modulation high temperature superconducting electrical machine (DSFM-HTSM) has been proposed, in which the armature windings and the HTS magnets are mounted on the outer and inner stator respectively, realizing stationary seal of the coolant and brushless transfer of the excitation current. The HTS magnet system is the core component of the DSFM-HTSM, consisting of the HTS magnets and the cryogenic refrigeration system, the design and safe operation of which are a key issue. Therefore, this paper focuses on the thermal loss analysis, design and test methods of the new HTS magnet system for the DSFM-HTSM. An atypical HTS magnet with small dimensions is proposed to suit the topology of the DSFM-HTSM. The different thermal loss sources are carefully analyzed and theoretically calculated, considering the characteristics of each source. The detailed design process of the HTS magnet system is presented. Moreover, an experimental platform is built and tested to verify the validity of the thermal loss analysis and design method. The corresponding research results can lay the foundation for the development and application of the large scale DSFM-HTSM, and can provide some reference for the analysis and design of similar HTS magnet systems.

Numerical comparative study on seismic response of half-span and full-span scaled models of a floating type cable-stayed bridge

This study compares the results of numerical simulations of half-span and full-span cable-stayed bridge models based on the seismic response of the pylons and main girders subjected to earthquake loads. The half-span model represents the most critical condition of the bridge during the construction phase, while the full-span model represents the bridge in operational phase. The three-dimensional finite-element modeling of the two bridge models uses data from the longest existing cable-stayed bridge in Indonesia which was scaled down geometrically to 1/160, using Midas CIVIL software. The Kobe earthquake record from the PEER Strong Motion Database was used in this study by applying the spectral matching method to modify its acceleration according to the location of the existing bridge being analyzed. This study also examines the influence of the directional effects of earthquake load relative to the longitudinal axis of the bridge, namely 0, 45, and 90 degrees. The results of the analysis show that for the half-span bridge model, the maximum acceleration occurs at the top of the pylon due to earthquake excitation at 90 degrees direction, with an amplification factor of 4.658, while the amplification factor in full-span bridge conditions is only 2.44. In addition, in both the half-span and full-span bridge models, the largest acceleration amplification factor occurs in the main girder that is caused by earthquake excitation at 90 degrees direction. The largest transverse displacement occurs at the free ends of the main girder, but not in the full-span model. The results of the study indicate that during the detailed design process the designer has to consider the effect of earthquake on the strength and stability of the bridge during construction especially if the balanced cantilever method applies.

Experimental and numerical studies of a novel three-dimensional isolation device incorporating disc springs with U-shaped dampers

To improve the asymmetric hysteretic capacity, enhance the insufficient energy consumption capacity, and release the horizontal constraint of disc springs, this study proposes a novel three-dimensional isolation device, which is mainly composed of disc springs, U-shaped dampers, and a sliding layer. The novel device is to bear the dead weight of superstructures by the disc springs and dissipate the major seismic energy by the U-shaped dampers. A quasi-static test is conducted to verify the proposed working mechanism. Furthermore, the finite element model of the novel device built by Abaqus software is validated based on the test results. Parameter analysis indicates that the length of straight parts and the thickness of U-shaped dampers significantly affect the horizontal mechanical behavior of the novel device. Moreover, the outer diameter of disc springs, and the length of straight parts, and the thickness of U-shaped dampers play essential roles to enhance the vertical mechanical behavior of the novel device. Detailed design processes of the novel device are conducted based on the numerical results.

Fractional-Order Linear Active Disturbance Rejection Control Strategy for Grid-Side Current of PWM Rectifiers

To further improve the performance of linear extended state observer (LESO), a novel fractional-order linear extended state observer (FOLESO) is proposed in this paper. By incorporating a fractional-order term into the framework of traditional LESO, the design of FOLESO is more flexible and thereby the disturbance estimation error can be further reduced. Based on the proposed FOLESO, a fractional-order linear active disturbance rejection control (FOLADRC) strategy has been designed for grid-side current control of three-phase voltage-type pulse width modulation (PWM) rectifiers. In this way, the harmonic suppression property can be enhanced without sacrificing the tracking performance, and the ideal grid-side current can be achieved. Furthermore, the detailed design process, implementation mode and parameter tuning of FOLADRC are also given in this paper. The theoretical analysis and experimental results show that the proposed method is effective and superior to the traditional PI control or linear active disturbance rejection control (LADRC) strategy.

Capturing mental models: An analysis of designers actions, ideas, and intentions

What do designers actually do while they are designing? How about their ideas and intentions toward a specific design activity? These issues are still urgently in need of resolution since designers play such a crucial role in the design process. However, existing research primarily concentrates on the explicit knowledge representation of designers' activities, but ignores tacit information that is underlying the motivation behind those activities. Fortunately, as a psychology-based inner cognitive representation of external reality, mental models take us a glimpse into explaining and driving designer activities. Based on the above, this paper proposed a novel framework with Latent Dirichlet Allocation and Word2Vec integrated harmoniously to capture the designer' activities. Additionally, both the know-how and know-why knowledge were represented by eliciting knowledge structure and belief structure of mental models respectively. Based on the distribution values of these two structures, the using opportunities of designer’s ideas are further explored to reveal their potential for being adopted, improved, explored, or discarded during the design process. Then the detailed design process is characterized by mental models to express the designers actions, ideas, and intentions for the artifact that they are designing. Finally, the experimental results performed a practical design case demonstrating that our proposed framework is applicable and helpful for designing.

Weighted topology optimization of back-up supporting structures of antennas

In a working environment, the supporting structure usually suffers from asymmetric exterior loads with some finite elevation angles, leading to an asymmetric and irregular structure when applying traditional topology methods. To solve this problem, in this article, a weighted topology optimization method based on a shape feature function is presented, with an innovative concept of shape feature control function, which is employed to reshape the stiffness distribution and make the optimized structure symmetric for the manufacturing process. Topology optimization is also performed under fixed connection constraints. By introducing both the shape control and electromagnetic characteristics functions into the topological design domain, a relatively symmetric and regular topology structure is obtained through the weighted topology optimization method under the asymmetric exterior loads, which benefits the following detailed design and manufacturing process for reflector antennas. Numerical simulation demonstrates the effectiveness and advantages of the proposed method.

Wideband Linear-to-Multi-Polarization Converter Based on Active Metasurface

This paper proposes a transmission-type linear-to-multi-polarization converter based on cascading four-layer metasurface integrated with PIN diodes. By controlling the states of the PIN diodes, the polarization maintaining (PM) which means transmission without conversion, linear to linear (LTL), linear to right-hand circular polarization (LTRCP), linear to left-hand circular polarization (LTLCP) conversions can be realized. When the PM is realized, the incident wave will pass through the polarizer with low loss over wideband, the isolation is higher than 30 dB. When the linear-to-circular polarization conversion is realized, the incident linearly polarized (LP) wave can be converted to left-hand circularly polarized (LCP) or right-hand circularly polarized (RCP) wave with a relative bandwidth over 40%. When the LTL polarization conversion is realized, the polarization conversion ratio (PCR) is greater than 0.9 from 2.58 to 3.89 GHz. The overlapping bandwidth of the four operating states is 36%. The detailed design process and equivalent circuit of the proposed polarizer are analyzed in this paper. A sample consisting of 10 × 10 elements is fabricated. The measured and simulated results are in good agreement. To the authors’ best knowledge, this is the first reported reconfigurable polarizer capable of PM, LTLCP, LTRCP, and LTL polarization conversions within wideband. The proposed device can play an important role in polarization diversity and RF-integrated aperture of wideband channel multiplexing technology.

Time-Domain Analysis and Optimal Design of LLC-DC Transformers (LLC-DCXs) Considering Discontinuous Conduction Modes

<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> -DC transformers ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> -DCXs) operate under fixed-frequency and open-loop conditions to achieve high efficiency and are promising converters that can be used in the auxiliary power units (APUs) of electric locomotives. An optimal design method of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> -DCXs is proposed in this paper. First, the time-domain expressions of the symmetric half-bridge <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> resonant converter with split resonant capacitors are derived. A current increment method is proposed to determine the expressions. Second, the discontinuous conduction mode (DCM) and voltage gain limiting conditions are used to obtain the magnetizing inductance ranges. The converter losses and zero-voltage-switching (ZVS) ranges are considered to determine the final magnetizing inductance. A 10 kW prototype is used as an example, and a detailed parameter design process is implemented. Compared with conventional design methods for the magnetizing inductance, the proposed method can effectively determine the maximum magnetizing inductance for the DCM operation of the converter. The effectiveness of the proposed method is proven by the simulations and experimental results obtained for the 10 kW <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LLC</i> -DCX prototype. The maximum efficiency of the designed converter is 98.12% under the full load.

Design of the process of CO2 removal in NGCC by potassium taurate solvent

One of the most mature technologies for removal of carbon dioxide from gaseous streams is chemical absorption and aqueous solutions of alkanolamines are employed, with Monoethanolamine (MEA) considered the benchmark solvent. However, its volatility and toxicity and the need for a lot of energy for regeneration made research focus on possible solvents that can perform the desired treatment of gaseous streams while reducing production and operating costs and the environmental impact, to be considered as substitutes. The process based on amino acid aqueous solutions, one type of these new solvents, has the advantage of an improved sustainability and, as the one employing aqueous solutions of potassium taurate, can also benefit of the enhancement due to the reaction of precipitation. In this work a rigorous rate-based model, built in the commercial process simulator ASPEN Plus®, properly customized for the representation of the system, is used to carry out a detailed process design for the CO2 removal section of a NGCC plant by an aqueous solutions of potassium taurate, for which no previous papers on the topics have been found in the literature. The scheme is optimized and the performances of the process are evaluated for different targets of CO2 removal.

Selection of foundation type of hospital building using analytical hierarchy process

In order to develop the Ministry of Defense Hospital dr. Suyoto in Bintaro, South Jakarta, a new 27-storey building will be built on the south side of the hospital complex. This study aims to select the type of foundation that is able to support the building above it, but with minimal disturbance due to vibration, noise, mud, and excavation, because the hospital must continue to operate, and relates to aspects of cost, time, and scope. The method used is the Analytical Hierarchy Process (AHP) involving five respondents who are considered construction experts from the Construction Center (Puskon) officers, planning consultants, supervisory consultants, and contractors. The results of the study found that concrete pile foundations with Hydraulic Static Pile Drivers (HSPD) were the most suitable for new building foundations from the five criteria and four alternative choices of foundations. In the detailed design process by the planning consultant, several pile caps were found that coincide with each other so it was decided to combine them into a large pile cap which also functions as a raft foundation. So that in its implementation, a combination of concrete piles with HSPD and raft foundations is used.

Designing a Mobile-Messaging App-Based Teachers’ Community of Practice in India

A mobile-based messaging app (MMA) was implemented as a teachers’ community of practice in the Indian context through a large-scale educational initiative. The development process adopted a Design-based Research approach to test underlying theories in real-world settings. The researchers theorised the pedagogical affordances of the MMA Telegram using Davis and Chouinard's theoretical framework of affordances, defined as a relational process among users, designers, the environment, and the artefact. This paper discusses the iterative design process in detail. The findings showed that the MMA encourages accessibility and for teachers to showcase their practice in the online community of practice and refuses (does not allow) the development of the online community of practice as an epistemic community.

High-Performance Control Simulation of PFC Converter for Electric Vehicle Charger

In order to solve the problems of low power factor and large harmonic pollution of some electrical equipment connected to the power grid, such as electric vehicle charger system, the author proposes a high-performance control simulation study of a PFC converter for electric vehicle charger. Using the staggered parallel boost power factor correction circuit topology of electric vehicle chargers as the front stage, its high power factor and low harmonic current characteristics can reduce the pollution to the power grid, and the detailed design process and loss analysis of the circuit are given. Through the digital control method and hardware optimization design, the loss is reduced, and the conversion efficiency of the power factor correction converter in the full power range is high, which meets the efficiency requirements of the platinum version and achieves the goal of energy saving and environmental protection. The test results show that the actual efficiency of the experimental prototype is 97.43%, 97.55%, and 97.36%, which are far higher than the efficiency requirements of the platinum version. Conclusion. The high-performance control of the PFC converter of the electric vehicle charger has certain guiding significance for the application in the electric vehicle.

Universal Virtual Synchronous Generator Based on Extended Virtual Inertia to Enhance Power and Frequency Response

Virtual synchronous generators (VSG) are considered a new generation of grid-friendly inverters with the same inertial support characteristics as synchronous generators (SG). However, the inertia support comes with the side effects of power and frequency response deterioration. The existing VSG power oscillation suppression methods have limitations such as complex controller parameter tuning, altering the frequency support characteristics, and power quality degradation. To address these issues, this paper proposes a universal VSG control strategy based on extended virtual inertia (VSG-EVI). Herein, the virtual inertia is no longer a constant or varying number; it is endowed with frequency domain characteristics to improve the VSG transient responses. Moreover, a detailed parameter design process is given in detail. Compared with the conventional VSG (CVSG), VSG-EVI significantly suppress the power and frequency oscillations. Compared with the existing VSG oscillation suppression methods, VSG-EVI addresses the issues of the reduction of frequency support capability, whereas the controller parametric design process is simplified with the proposed intuitive extended virtual inertia. Finally, the proposed VSG-EVI method is thoroughly validated by experiments under both grid-connected and stand-alone modes.