Real Design Research Articles

Research of influence of operational factors on parameters fuel delivery accumulator system CR engines RT-FLEX

The results of a computational study of the influence of operational factors on the fuel supply process by the accumulator system CR of RT-flex engines are presented. In the model used in the study of fuel supply in the accumulator system processes that occur in all its essential elements are described. As an accumulator, a constant pressure source is considered. The most detailed analysis is the operation of the injection control unit that determines the processes in the high-pressure system. Carefully presented nozzles, the elements of which are fully consistent with the real design. A change in the basic characteristics of injection with variable values of the temperature of heating the fuel, its viscosity, pressure in the accumulator and the pressure of the nozzle needle lift is considered. The most significant effect is the viscosity and pressure in the accumulator. An increase in viscosity (lowering the heating temperature) leads to a significant decrease in the cyclic supply of fuel and a decrease in the stroke of the metering piston with constant fuel supply phases. The cycle delivery increases with temperature from 500 C to 90-1100 C from 0,013 to 0,022 kg – 1,69 times. Obviously, the determining factor in this dependence is the movement metering piston injection control unit. This indicator changes in a close way, increasing in the same range from 7.4 to 10.5-10.8 mm. Additional information about the movement of the QP is the speed of its movement. In the direct (working, injection) stroke, it increases with increasing temperature in the above range from 0,135 to 0,244 m / s. As for the fuel pressure in the nozzle, then the influence of temperature is small. It decreases from 610 to 600 bar − less than 2 % (in the ratio of 1,016). This pattern indicates the decisive influence of the hydraulic resistance of the elements of the high pressure path on the pressure in the nozzle. In a similar way, the injection parameters change with decreasing pressure in the accumulator. One of the operational parameters of the fuel supply system is the liftingpressure of the nozzle, which depends on the force from the spring. To assess the influence of the pressure of the nozzle lift, the injection process was simulated at various spring tightening pressures. The range of variation of was 300-450 bar with a nominal value of 375 bar. No noticeable effect was on injection characteristics. The change in the cyclic delivery does not go beyond 3,2 %; the difference in the path of the QP for the boundaries of the range is 2,2 %, and the velocity of the QP remains within 1,8 %. The pressure in the nozzle channel remains unchanged.

Оценка несущей способности контактного соединения полюсного вывода свинцовой аккумуляторной батареи

Introduction. The data given in the article show that the problem of increase of fire safety at operation of vehicles is actual. The main purpose of the article is to develop a scientifically based method of examination of contact connections of pole terminals of starter batteries, which have signs of high transient resistance or change in geometrical shape in order to find out the reason of damage in the course of fire-technical expertise. Materials and methods. The researches were carried out with the use of a scanning-electron microscope JSM-6390LV with an attachment for energy-dispersive microanalysis. The objects of research were pole terminals of a lead-acid storage battery of European type and their tips. Contact surfaces of the tips were analyzed without preliminary sample preparation. Theoretical background (theory and calculations). A physical and mathematical model of ultimate load-bearing capacity of lead battery terminal, which corresponds to real design, has been developed. On this basis, there is formulated a computational and practical algorithm for expert analysis of its mechanical and geometrical characteristics. The solution has been simplified to short calculating formulas, allowing to estimate the contact load-bearing capacity. The applicability of the developed mathematical model to carrying out fire-technical exami­nations is shown by a concrete example. Results and discussion. Examples are given of car fires, which were caused by loss of load-bearing capacity in the contact of battery terminals with wire-end terminals during in the process of operation. Pictures of the result of high transient resistance on the contact surface and its elemental composition are given. Experimental data confirmed that the transfer of the material of the pole leads to the tips of wires in the form of drops of lead and its layers is a significant forensic feature in determining the cause of the fire. Conclusions. The method of determination of load-bearing capacity of contact of a lead battery pole to the wire end, on the basis of which it is possible to draw a conclusion about participation of great transient resistance in the contact to the subsequent fire, is offered. The data given in the article may be used by specialists during an expert examination of lead battery terminals, seized from places of fires, in order to establish the mechanism of their damage and, finally, the cause of a fire.

Dielectric Cavity-Insulator-Metal (DCIM) Metamaterial Absorber in Visible Range.

For many years, metamaterial absorbers have received much attention in a wide range of application fields. There is an increasing need to search for new design approaches that fulfill more and more complex tasks. According to the specific application requirements, design strategy can vary from structure configurations to material selections. A new combination of a dielectric cavity array, dielectric spacer, and gold reflector as a metamaterial absorber is proposed and theoretically studied in this work. The complexity of the dielectric cavities leads to a more flexible optical response than traditional metamaterial absorbers. It gives a new dimension of freedom for a real three-dimensional metamaterial absorber design.

Adaptive Selection and Clustering of Partial Reconfiguration Modules for Modern FPGA Design Flow

Dynamic Partially Reconfiguration (DPR) on FPGA has attracted significant research interest in recent years since it provides benefits such as reduced area and flexible functionality. However, due to the lack of supporting synthesis tools in the current DPR design flow, leveraging benefits from DPR requires specific design expertise with laborious manual design effort. Considering the complicated concurrency relations among various functions, it is challenging to select appropriate Partial Reconfiguration Modules (PR Modules) and cluster them into proper groups with a proper reconfiguration schedule so that the hardware modules can be swapped in and out correctly during the run time. Furthermore, the design of PR Modules also impacts reconfiguration latency and resource utilization greatly. In this paper, we propose a Maximum-Weight Independent Set model to formulate the PR Module selection and clustering problem so that the original manual exploration can be solved efficiently and automatically. We also propose a step-wise adjustment configuration prefetching strategy incorporated in our model to generate optimized reconfiguration schedules. Our proposed approach not only supports various design constraints but also can consider multiple objectives such as area and reconfiguration delay. Experimental results show that our approach can optimize resource utilization and reduce reconfiguration delay with good scalability. Especially, the implementation of the real design case shows that our approach can be embedded in Xilinx's DPR design flow successfully.

A Study on Optimal Design Process of Dual Rotor Axial-Flux Permanent Magnet Synchronous Motors

The core design elements of the motor for the co-robot joint are miniaturization and high torque. In this paper, a dual rotor axial-flux permanent magnet (DRAFPM) motor is proposed to improve the performance of robot joints. DRAFPM motors have the advantage of reducing iron loss and minimizing volume because they can remove stator yoke. When designing a motor with the same volume, it can be designed to increase the height of the fixed ruler by the thickness of the yoke of the fixed ruler and increase the number of turns. In the case of existing axial-flux permanent magnet (AFPM) motors, the shape of the three-dimensional structure is limited by radial laminating of stator. Therefore, considering the production of 3D printing, the shape of stator shoe is designed. The optimal design problem of DRAFPM motor consists of real and integer design variables. In addition, due to the structural characteristics of DRAFPM motors, 3D finite element analysis (FEA) is required, so it takes a long time to interpret. Therefore, this paper proposes an efficient optimal design process to optimize the remaining real design variables after prioritizing the integer design variables. The proposed optimization process is applied to the DRAFPM motor for robot joints, and the optimal design plan satisfying the design function is derived from various design variables to prove the validity of the optimization process.

Semi-empirical synergetic analysis of the shear capacity of steel fibre reinforced concrete slender beams of rectangular-sections without stirrups

Although steel fibre reinforced concrete (SFRC) has been widely used in various engineering structures, there is a lack of a reliable and unified method for predicting the shear capacity of reinforced SFRC slender beams. After conducting an extensive review of previous studies on the slender beams of rectangular-section without stirrups and the SFRC with the cold-drawn hook-end steel fibre, a database was developed based on 280 reinforced SFRC slender beams that failed in shear accompanied by 37 reinforced SFRC slender beams failed in flexure and 71 reinforced conventional concrete beams failed in shear. The comparison between the experimental results and the results predicted using existing formulae revealed that a more accurate empirical model is required to evaluate the effects of multi-factors on the shear strength of the reinforced SFRC slender beams without stirrups. Based on the model of the critical shear crack, a semi-empirical synergetic equation is developed to predict the shear capacity of reinforced SFRC slender beams without stirrups. The enhanced shear resistance of SFRC in the shear-compression zone, the dowel action of longitudinal tensile steel bars, the aggregate interlock between sides of critical shear crack, and the shear resistance of steel fibres across the shear cracks as well as the size effect of sectional depth are considered. Good prediction results with small dispersion can be obtained using the proposed semi-empirical model. Conservative and simplified equations are also provided as the lower bound of the experimental shear strength of the reinforced SFRC slender beams without stirrups for easier implementation of the proposed model in real engineering design practice.

TEMGYM Advanced – NanoMi lens characterisation

A complete analysis including finite element method (FEM) calculation, focal length properties, and thirdorder geometric aberrations of the open-source electrostatic lens from the NanoMi project is presented. The analysis is carried out by the software TEMGYM Advanced, a free package developed to carry out ray-tracing and lens characterisation in Python. Previously TEMGYM Advanced has shown how to analyse the aberrations of analytical lens fields; this paper expands upon this work to demonstrate how to apply a suitable fitting method to discrete lens fields obtained via FEM methods so that the aberrations of real lens designs can be calculated. Each software platform used in this paper is freely available in the community and creates a free and viable alternative to commercial lens design packages.

Guided-blended collaborative learning in speaking class: Voices of non-native English teachers and students from eastern Indonesia

The purpose of this qualitative study is to explore and address two important questions from ten qualified non-native English teachers and five students who have been actively involved as research participants: (1) how non-native English teachers help students improve their English speaking performance through guided-blended collaborative learning, and (2) how non-native English teachers and students view guided-blended collaborative learning as a way of improving students’ English speaking performance. Based on an in-depth interview with five students and an analysis of documents, it is clear that when teachers gave their students both synchronous and asynchronous feedback, the students' speaking skills improved. The data that has been analyzed thematically showed that collaborative learning is successful and should be utilized to teach speaking English as a foreign language, they found, teachers should use the following strategies when teaching GBCL: 1) Mixing synchronous and asynchronous learning; 2) Being guided or controlled by the teachers; 3) Forming groups based on roles; 4) Peer tutoring and evaluation; and 5) Collaborative integrated tasks with technology. In addition, we would like future studies to use real experimental and control class designs to conduct guided blended collaborative learning.

Computational and experimental study of longitudinal stability of the thin-walled flat bar structure

The paper studies longitudinal stability of the centrally compressed flexible flat bars using computational and experimental methods. Calculations were carried out according to the dynamic analysis methodology in the LS-DYNA software package. This methodology is based on three determining factors, i. e. volume, technological deviations and real-time mode. When constructing a hinged bar model, 3D finite elements, elastic-plastic material model, asymmetrical cuts of small volumes simulating geometric technological deviations were used. Critical forces determined by the methodology were compared with the Euler forces and with the experimental data. The experiment was carried out on bars with pointed ends, which were abutted against the angular technological equipment and provided with free rotation of the bar ends. As a result of the computational and experimental study of the flexible bars stability, it was established that in real bar designs there appeared initial shape imperfections noticeably affecting the critical forces magnitude, and the more flexible the bar was, the stronger this effect was. Quantitative relationship was also found between the experimentally measured critical forces and those calculated by the methodology and by the Euler formula. The issues of the origin of initial form imperfections in real bars were touched upon. Three possible directions for searching for a solution to the problem of bar stability using the methodology of dynamic analysis are shown depending on the method of introducing technological deviations into the structure calculation scheme. Diagrams of the hinged flat bars deformation during compression tests are provided.

Multi-objective Topology Optimization of the Temperature Field Considering the Material Nonlinearities

This paper presents a multi-objective topology optimization method for the temperature field considering the material nonlinearities. Although a large number of papers have studied the topology optimizations of the heat transfer problems, none of them considered the influence of the material nonlinearity properties. In this paper, the material nonlinearity is considered. Based on the nonlinear assumption, the mathematical model of the corresponding topology optimization is presented first. Then, the sensitivities of the objectives and the constraints respect to the design variables are derived. And the optimization routines are discussed. After establishing the theories and solving scheme, a software is developed by MATLAB for the topology design of the nonlinear heat transfer. Several nonlinear numerical examples are presented. And the corresponding optimal results generated under the linear assuming are also collected for comparisons. Furthermore, this paper also simply discusses the preventing approaches of instabilities and the implementation methods of some other unusual engineering constraints. These true engineering considerations are very helpful for the real industry design experiences.

A Reliability System Evaluation Model of NoC Communication with Crosstalk Analysis from Backend to Frontend

Network on chip (NoC) is the main solution to the communication bandwidth of a multi-processor system on chip (MPSoC). NoC also brings more route requirements and is highly prone to errors caused by crosstalk. Crosstalk has become a major design problem in deep-submicron NoC communication design. Hence, a crosstalk error model and corresponding reliable system with error correction code (ECC) are required to make NoC communication reliable. In this paper, a reliability system evaluation model (RSE) of NoC communication with analysis from backend to frontend has been proposed. In the backend, a crosstalk error rate model (CER) is established with a three-wire RLC coupling model and timing constraints. The CER is used to establish functional relations between interconnect spacing, length and signal frequency, and test system reliability. In the frontend, a reliability system performance model (RSP) is established with a CER, reliability method cost and bandwidth. The RSE summarizes the frontend and backend model. In order to verify the RSE model, we propose a reliability system with a hybrid automatic repeat request technique (RSHARQ). Simulation demonstrates that the CER model is close to real circuit design. Through the CER and RSP model, the performance of RSHARQ could be simulated.

Usage of personas in the construction industry

Background: This study on the use of personas was carried out during a building trade related software development EU project. Participants were introduced to the personas tool and encouraged to use it in their work in technical development. Methods: A questionnaire was delivered three months after presentation and explanation of the remote tool, inquiring about benefits, drawbacks, intention of using personas in the future, and the role of usage related information as a whole in technical development. Results: Previous knowledge about the tool, perceptions of the tool and its actual use seemed to influence developers in their decision to use it or not. Conclusions: Almost half of the organizations in our study use real user-centric design methods in their technical development; this can ease the path for wider adoption of the methods when needed. One possible solution to strengthen the understanding and adoption of the user-centric methods is to spread information among technical developers, by identifying and using efficient communication channels, such as tailored training. User-centric methods seem to have gained followers in the technical development arena, indicating that this may be a feasible way for further adoption of user centricity in product development.

Enabling technology and core theory of synthetic biology.

Synthetic biology provides a new paradigm for life science research ("build to learn") and opens the future journey of biotechnology ("build to use"). Here, we discuss advances of various principles and technologies in the mainstream of the enabling technology of synthetic biology, including synthesis and assembly of a genome, DNA storage, gene editing, molecular evolution and de novo design of function proteins, cell and gene circuit engineering, cell-free synthetic biology, artificial intelligence (AI)-aided synthetic biology, as well as biofoundries. We also introduce the concept of quantitative synthetic biology, which is guiding synthetic biology towards increased accuracy and predictability or the real rational design. We conclude that synthetic biology will establish its disciplinary system with the iterative development of enabling technologies and the maturity of the core theory.

Oblique scattering from non-Hermitian optical waveguides

A judicious design of gain and loss leads to counterintuitive wave phenomena that are inaccessible by conservative systems. Notably, such designs can give rise to laser-absorber modes and anisotropic transmission resonances. Here, we analyze the emergence of these phenomena in an optical scatterer with sinusoid gain-loss modulation that is subjected to monochromatic oblique waves. We derive an analytical solution to the problem, with which we show how the scatterer parameters, and specifically the modulation phase and incident angle, constitute a real design space to access these phenomena.

Improvement of the design of the plow-subsoiler-fertilizer to increase soil fertility

The use of intensive technologies for the cultivation of agricultural crops provides for the application of fertilizers in the process of tillage. This reduces the compaction of the soil, increases its fertility and the quality of the crop. The purpose of these studies is to develop a universal working tool that allows you to combine several technological operations in one pass of the unit. The authors have developed an original design of a plow-subsoiler-fertilizer. This combined working body includes a reversible plow and a vibratory subsoiler with fertilizer ducts. This solution allows you to combine the application of fertilizers when plowing the field, loosening the subsoil layer and mixing the soil. As a result of the work, the dependences of the geometric dimensions of the structure on the traction resistance to movement in the soil were obtained. To implement the developed idea into a real design, the main parameters of the plow-subsoiler-fertilizer are determined. Particular attention is paid to the calculation of the spring mechanism that ensures the vibration of the subsoiler. The optimal number and location of belleville springs in the block and shock absorber were selected, at which the subsoiler will perform self-oscillations with a given amplitude.

Webtoon’s Effect on Students’ Reading Comprehension at School

This study investigated the effect that employing the Predicting Strategy with Webtoon would have on MTsS Awaliyah students' reading comprehension during the academic year 2021-2022. This study was conducted using a quantitative methodology and a real experimental pretest-posttest control group design. Eighth-grade enrollment was 60 pupils, who were equally distributed between two classes. The samples were comprised of the whole population and were chosen using a simple random selection technique. There were 30 pupils in both the experimental class (VIII-A) and the control class (VIII-B) (VIII-B). The pre-test and post-test each consisted of 20 multiple-choice questions, and they served as the data collection instruments. Using 58 degrees of freedom (df) and a significance threshold of 0.05, a t-test revealed that the value of to was 6,515, and that ttable was 1,673. This equation indicated that to is more than ttable (6,515 > 1,673). According to the study's findings, the alternative hypothesis (Ha) should be accepted, whereas the null hypothesis (Ho) should be rejected. It suggests that the experimental class scored differently than the control class after the therapy was administered. The Predicting Approach with Webtoons has a major impact on students' reading comprehension.

Multi-objective optimization of geosynthetic-reinforced and pile-supported embankments

The design of geosynthetic-reinforced and pile-supported (GRPS) embankments is traditionally optimized by searching for the most cost-effective solution among several workable candidates. The candidates are usually based on experiences of engineers, and the real optimal design could be therefore missed. This paper intends to address the above-mentioned issue by systematically optimizing the design of GRPS embankments considering simultaneously the cost and the safety in the entire design space. It is thus a multi-objective optimization (MOO) problem that differs from the studies only focusing on minimizing the construction cost. A practical MOO procedure is proposed in this paper, and it is applied to an illustrative GRPS embankment case. A set of nondominated optimal designs (Pareto front) are obtained at first, allowing an informed design decision. Then, four candidates located on the Pareto front are highlighted. Each of them represents an attractive design: the safest, the least-cost, the best trade-off (knee point) considering the two objectives, and the cheapest one for a target safety requirement. Finally, the optimal design can be selected from these four candidates depending on specific project purposes. For the case study, the knee point design leads to improvements in both the two defined objectives (i.e., decreased cost and increased safety) compared to the initial design, showing great benefits of performing a MOO analysis. By using the procedure, the optimal designs are also efficiently determined for the cases of different embankment heights.

New design for unconventional timing silent chain system of inline engine

More and more unconventional timing silent chain systems are used in the low-emission vehicles or hybrid vehicles, but engineering practices show that the classical design method cannot ensure the stability and the feasibility anymore. According to the angular velocity fluctuations of crankshaft, the maximum accumulation length is calculated to design the ideal path of the tension side chain. The tension rate is defined to determine the ideal chain path at the loose side. In order to match the ideal chain paths with the actual chain length, the pitch variation algorithm is proposed. Based on a specific inline engine, the unconventional timing silent chain system is designed by the classical design method and the new design method respectively. The design process proves that the new method is belonging to a real parametric design, and it can expediently and quickly obtain the results. With the dynamics simulation comparison, the results show that the operation performance of the unconventional timing system can be roundly and significantly improved by using the new design method. Furtherly, this new design method is not only suitable for the unconventional timing system, but also suitable for the other types of timing systems.

Visible imaging system optical design by continuous optimization of glasses

Choice of lenses materials in optical design is crucial to reduce aberrations down to an acceptable level. Commercial glasses do not cover a continuous range of refractive indices and must be selected in a discrete library making them discrete variables in any optimization design process to achieve the final optical design to be manufactured. This paper proposes an alternative method to avoid the complicated discrete variables optimization process thanks to a two-steps continuous optimization methodology starting with fictitious glasses models before jumping to the real glasses optimization design. The illustration of this process and achieved results are presented on an example of optical system which validates our proposed method.

A Novel Meta-Heuristic Algorithm for Numerical and Engineering Optimization Problems: Piranha Foraging Optimization Algorithm (PFOA)

This paper provides a novel meta-heuristic optimization algorithm for solving continuous optimization problems efficiently in the field of numerical and engineering optimization: Piranha Foraging Optimization Algorithm (PFOA). The algorithm is inspired by the flexible and mobile foraging behaviour of piranha swarm and divides their foraging behavior into three patterns: localized group attack, bloodthirsty cluster attack and scavenging foraging, simulates the above behaviors to construct two dynamic search processes for exploration and exploitation. PFOA uses three strategies of non-linear parameter control, population survival and reverse evasion search to enable populations to have better population diversity at different stages of the search and to help find better solutions. To gain insight into the performance of PFOA, visualization methods were used to assess the efficiency of PFOA optimization and to analyse the impact of the characteristics of the three foraging modes, the sensitivity of the parameters and the size of the piranha population on the algorithm. The algorithm performance was further tested with 27 CEC benchmark functions and four real engineering design optimization problems, and the results were compared with 13 well-known meta-heuristics. Test results based on statistical methods such as box-line plots, Wilcoxon rank sum test and Friedman test in multiple dimensions (30, 50, 100 and fixed dimensions) show significant differences compared to other algorithms and that the performance of the algorithm is stable and in significant improvement. The unique advantages of PFOA in terms of the equilibrium of convergence speed and exploration can avoid getting trapped in local optimum regions and effectively solve optimization problems in complex search spaces.