Software Simulation Research Articles

Microstructural and tribological characterisation of an 3D printed Ti-6Al-4V alloy under annealing treatment for prosthetic implantation

Annealing treatments was implemented on a laser powder bed fusion-processed (LPBF) Ti-6Al-4V (Ti Gr23) alloy to improve its tribological attributes. Wet reciprocating wear tests at 5 N normal load and sliding velocities (5 mm/sec) were utilised to evaluate their wear behavior. The test was performed using a SS304 spherical ball of diameter 5 mm and a stroke length of 5 mm in simulated body fluid (SBF) at body temperature. A set of optimal process parameters were used for the fabrication of porous less Ti64 sample using porosity parametric simulation in Additive ANSYS software. The microstructural and mechanical characterization were performed and corelated wear mechanism. The results indicate that the partial decomposition of α’→α + β occurred during the annealing treatments. A needle-like martensite α’ phase was noticed on the as-sintered sample. The worn morphologies and mechanisms depend significantly on the microstructural characteristics while microstructural characteristics depend significantly on annealing treatment. Scratches observed along the wear track of Ti64 alloy, accompanied by islands of microscopically smooth oxide layers detaching from the surface, suggest a mixed mode of wear characterized by both abrasive and adhesive mechanisms. Annealing treatment was improved the tribological behaviour of Ti64 alloy.

Performance of the chloride ions transport in recycled concrete via salt-freezing coupling

Salt-freezing coupling is one of the main factors affecting the durability of recycled concrete. Investigating the chloride ion transport performance in recycled concrete containing recycled aggregate is essential to clarify the resistance of recycled concrete to chloride ion erosion due to the use of recycled aggregate produced from waste concrete. The objective of this paper is to investigate the migration behaviors and binding characteristics of chloride ions in recycled concrete, which were exposed to the salt-freezing coupling environment. The microstructure of the recycled concrete was conducted through scanning electron microscope (SEM), while the process of chloride ions migration was simulated by COMSOL software. The results indicated that the degree of recycled concrete, prepared by recycled coarse aggregate [RCA]and different particle size fly ash [NF], frost damage was higher in a 3 % NaCl solution compared to water. The contents of free chloride ions in recycled concrete subjected to freezing-thawing [F-T] cycle in water was minimally influenced by the NF content or the replacement rate of RCA. Under F-T conditions in a 3 % NaCl solution, increasing the NF content at the same replacement rate of RCA results in a decreasing-then-increasing trend in both the free chloride ion content and the chloride ion binding capacity in the concrete. Recycled concrete containing 15 % NF had a superior salt frost resistance compared to recycled concrete without NF or with ultrafine fly ash [SF]. With the replacement rates of RCA increasing, the contents of free chloride ions rose, the salt resistance of recycled concrete decreased. Using Fick’s second law, the chloride ion diffusion coefficient was calculated using MATLAB, and COMSOL software simulation accurately portrayed the diffusion state of free chloride ions in the recycled concrete.

When is the supply chain resilient? Customer and operational perspectives

Disruptions can adversely impact supply chain resilience, and measurement of these impacts is a challenging problem in research and practice. Using a practical set of resilience indicators characterising preparedness, recovery, network, and process areas, we analyse how different indicators can support analysis and decision-making from customer and operational perspectives of resilience. Disruptions and performance impacts are modelled with the help of discrete-event simulation in anyLogistix supply chain analytics software. For simulation, we construct three distinct network designs and analyse their resilience using three indicators: on-time delivery (OTD), fill rate (FR), and time-to-recover (TTR). We derive some useful theoretical and practical insights. OTD is a suitable indicator of a customer resilience perspective. However, there may be delays in reporting disruptions in the supply chain using OTD. FR can immediately alert users about interruptions in material flows and so it is better suited to the operational resilience perspective. Moreover, we propose a new interpretation of the TTR indicator by considering it from the customer resilience perspective. We reveal the role of OTD and FR as disruption indicators when measuring TTR and provide associated managerial insights. Our study can be helpful for development of multi-stakeholder-oriented resilience performance assessment systems.

Lagrange‐dual‐based fully distributed economic dispatch in smart grids with transmission line losses

AbstractEconomic dispatch constitutes an important element within the hierarchical control framework of smart grids. Its effective implementation is imperative for cost reduction in generation, enhancement of operational efficiency, and power systems stability. This paper tackles the distributed economic dispatch problem in smart grids with transmission line losses. First, the economic dispatch problem is transformed into its Lagrange dual problem using convex optimization theory, accompanied by a description of the strategy for addressing inequality constraints. Then, a fully distributed optimization algorithm is developed under free initial state through the fusion of nonsmooth analysis and the primal–dual method. Furthermore, based on this algorithm, a modified algorithm with lower communication overhead is presented. Finally, software simulations and hardware‐in‐the‐loop tests are performed to verify the developed scheme.

Material selection and performance analysis of RF-MEMS switch for MM-WAVE applications

This paper presents the design, simulation, and investigation of a fundamental structure for capacitive MEMS switches in a shunt configuration. The main objective is to select materials that achieve low actuation voltage while maintaining RF and dynamic performance, especially for mm-wave applications. The proposed design consists of a Fixed-Fixed flexure beam with dimensions of 260 μm in length, 100 μm in width, and 0.5 μm in thickness. Considering the impact of squeeze film, 60 holes are integrated into the beam membrane, each measuring 64 μm² (8µm x 8µm), and a final gap of 1.9 μm is implemented. The suitability of materials for the beam membrane and dielectric layer in capacitive MEMS switches has been thoroughly examined through a combination of theoretical analysis and software simulations. Aluminum (Al) has emerged as the ideal choice for the beam membrane in mm-wave applications. This preference is defensible by its simulated results to offer a low pull-in voltage of 4V, a quality factor of 1.18, and a switching time of 67 microseconds. Similarly, Si3N4 has been identified as appropriate material, offering a upstate capacitance of 91fF and a downstate capacitance of 7.1pF.

Software implementation of an automatic control system for technological process with training elements

A relevant applied issue of technological process control quality improving with changing operating parameters — temperature and pressure is considered. To solve this issue, information and control system (ICS) is created, based on the principles of machine imitation. The main requirements for the ICS, its purpose, structure and capabilities are given. The results of the ICS operation are presented. Keywords automation, control system, computer simulator, imitation, software simulator, programming language

A Novel Design of a Quadratic Koch Fractal Nano Antenna for THz Application

The study, called A Novel Design of a Quadratic Koch Fractal Nanoantenna, aims to create and study a brand-new microstrip nanoantenna that works in the THz range, specifically between 100 and 130 THz, and can handle a wide range of optical communication frequencies. We examine two unique geometries, specifically the quadratic Koch fractal patch (QKF) and the complementary quadratic Koch fractal patch (CQKF), utilizing two different dielectric materials as substrates. We employ silicon (Si) dielectric material because of its high dielectric constant (11.9), while we use the silicon dioxide (SiO2) dielectric material because of its dielectric constant (4). The feeding method employed to stimulate these nanoantennas has been waveguide feed at a frequency of 50 Ω.We have employed a software simulator, available for purchase as CST STUDIO SUITE, to achieve the established objectives for assessing the performance of each proposed nanoantenna.

Design of Geothermal Groundwater Heating and Cooling Plant: A Trial Study in Eleme Fertilizer Company in Niger Delta Region

A geothermal groundwater heating and cooling plant consisting of a heat pump and heat exchanger has been designed. Geothermal heating and cooling systems play a crucial role in the decarbonization of the environment, helping to prevent global warming and promote energy savings due to the reduced energy required to power the plant, which in turn generates more geothermal energy for the heating and cooling needs of the fertilizer company. This study considered Eleme Fertilizer as a case study for the scaled-up and installation of the prototype designed of the geothermal groundwater heating and cooling plant. Both manual and software simulation designs were conducted based on material and energy balance principles. Error analysis and deviations were used to validate the design results. The results of the plant's unit design showed that the power drive, overall efficiency, and coefficient of performance for heating and cooling were 354.1 kW, 402%, and 2.82 & 1.05, respectively. For the heat exchanger, design type 10-E-01, the values for heat duty, overall heat transfer coefficient, exchanger area, and tube pressure drop were 309.5 kW, 0.2104 kW/m²°C, 60.32 m², and 390 MPa, respectively. Error analysis conducted on the design work showed negligible values of RMSE (0.02, 0.025, 20 and 0.656) and deviation (0.014, 0.05, 0.05, 0.002) for coefficient of performance of heating and cooling, heat pump efficiency and the drive power of the plant respectively. The values obtained from the design of the units in the geothermal plant were reasonable and are thus recommended for academic and industrial applications

Pre-design of bottom ash cooling using CFD simulation: a case study of the coal generator power plant in the PT. BEST Tanjung Enim of South Sumatera

The manual removal of bottom ash from the boiler is a hazardous activity due to the extremely high temperatures involved, ranging from 700 to 800°C. The objective of this research is to develop a cooling device to facilitate the bottom ash removal process for workers at PT. BEST Tanjung Enim and to measure the reduction in ash temperature achieved by cooling device. The design was created using computer aided design software and Computational Fluid Dynamics (CFD) simulations. Subsequently, a hypothesis is proposed, defining the bottom ash material as Silicon Dioxide (SiO₂) and equalizing the density of the bottom ash. To ascertain the temperature drop, variations in the screw conveyor’s rotation speed were tested at 40, 33, and 12 rpm, paired with cooling water velocities of 0.5, 0.75, and 1 m/s respectively. The findings of study indicated that a screw conveyor speed of 12 rpm combined with a cooling water velocity of 0.5 m/s yielded the lowest bottom ash temperature, reaching 402°C, thus significantly reducing the need for manual handling when the ash temperature remains at 800°C. Further study should explore the application of Discrete Element Method (DEM) simulations for modelling bulk material behaviour and the integration of additional cooling media to enhance system performance.

Design and Simulation of an Arduino-Based Password-Protected Door Locking System

In the contemporary world, where technology has advanced and with the incidents of thefts increasing, more traditional locking mechanisms such as a single lock and key are needed to offer better security. New reliable, intelligent, and smart door-locking mechanisms are necessary to improve the security and safety of residential or commercial properties. This paper aims to describe the design and implementation of an Arduino-based door lock system that includes an LCD for displaying the related information, a servo motor that controls the door's locking mechanism, and a keypad that will be used for user input. The suggested method is password protected since it asks the user for their password before accessing a door. When a user enters an erroneous password more than a predetermined number of times, the system also offers the option to reset the password and lock it out for a predetermined period. An additional feature of using the GSM module is to implement a function that notifies the owner of any unwanted access by sending a message to them when the door is locked after the number of erroneous passwords exceeds the set limit, thus alerting the owner of any unauthorized access. The suggested model's incorporation of these elements contributes to increased security. An online 3D design and simulation tool called Tinker cad is used to simulate the system initially. Thus, the suggested model of a password-enabled door-locking system improves security and offers a solution that is easily adjustable and user-friendly by integrating the hardware components and offering thorough simulation and testing through the software simulation using Tinkercad software.

Low-Cost Hardware Analog and Digital Real-Time Circuit Simulators for Developing Power Electronics Control Circuits

The paper describes low-cost hardware-based analog and digital real-time circuit simulators for the development of power electronics control circuits. During the process of designing and developing digital control circuits for power electronics systems, preliminary verification of control algorithms is required. For this purpose, software simulators such as Pspice, Psim, Matlab-Simulink, and many others are commonly used. Afterward, the developed control algorithm is implemented in the digital control system. For further verification of the implemented control algorithms, a hardware-based analog or digital simulator can be utilized. The paper presents the author’s proposed analog simulators. In the digital version of the simulator, TMS320F28388D microcontroller with 200 MHz clock was used. These simulators have demonstrated their usefulness in the development of power electronics systems.

Modelling and Analysis of Low and Medium-Temperature Pyrolysis of Plastics in a Fluidized Bed Reactor for Energy Recovery

With the growing demand for plastic production and the importance of plastic recycling, new approaches to plastic waste management are required. Most of the plastic waste is not biodegradable and requires remodeling treatment methods. Chemical recycling has great potential as a method of waste treatment. Plastic pyrolysis allows for the cracking of plastic polymers into monomers with heat in the absence of oxygen, allowing energy recovery from the waste. Fluidized bed reactors are commonly used in plastic pyrolysis; they have excellent heat and mass transfer. This study investigates the influence of low and medium process temperatures of pyrolysis on fluidized bed reactor parameters such as static pressure, fluidizing gas velocity, solid movement, and bubble formation. This set of parameters was analyzed using experimental methods and statistical analysis methods such as experimental correlations of changes in fluidized bed reactor velocities (minimal, terminal) due to temperature increases for different particle sizes; CFD software simulation of temperature impact was not found. In this study, computational fluid dynamics (CFD) analysis with Ansys Fluent was conducted for the fluidization regime with heat impact analysis in a fluidized bed reactor (FBR). FBR has excellent heat and mass transfer and can be used with a catalyst with low operating costs. A two-phase Eulerian–Eulerian model with transient analysis was conducted for a no-energy equation and at 100 °C, 500 °C, and 700 °C operating conditions. Fluidizing gas velocity increases the magnitude with an increase of the operating temperature. The point of fluidization could be determined at 1.1–1.2 s flow time at the maximum pressure drop point. With the increase of gas velocity (to 0.5 m/s from 0.25 m/s), fluidizing bed height expands but when the solid diameter is increased from 1.5 mm to 3 mm, the length of the fluidized region decreases. No pressure drop change was observed as the fluidized bed regime was maintained during all analyses. The fluidization regime depends on gas velocity and all the applied fluidization gas velocities were of a value in between the minimal fluidization velocity and the terminal velocity.

Thermal Behavior of a Historic Building Housing Books Across Past and Future Climate Scenarios

Climate change poses significant challenges for the renovation of historic buildings, requiring a careful balance between preservation and energy efficiency, particularly considering the forecasted rise in temperatures. This study focuses on a medieval building undergoing renovation, examining thermal behaviors based on future climate settings, with particular attention to the rooms housing a book collection. Books require controlled microclimatic conditions that must be ensured for their preservation; hence, the energy use for air conditioning control must be considered during the renovation planning phase. Through on-site monitoring of the thermophysical properties of the building envelope and indoor microclimate, along with energy model software simulations, both historic climate and global warming scenarios were evaluated for their potential impact on thermal behavior and consequently on energy consumption. This study aims at contributing to the long-term sustainability and resilience of historic buildings, as well as proposing best practices for planning interventions involving sensitive cultural heritage materials, considering the effects of climate change in the renovation process. The results show strategies to address the climatic changes through a methodology optimizing renovation interventions. The sizing of air conditioning systems coupled with a less stringent microclimate control mitigates energy requirements, in line with the sustainable management approach.

Intelligent Office Lighting Control Using Natural Light and a GA-BP Neural Network-Based System

Intelligent lighting control systems are essential for regulating office illumination. Both illuminance levels and uniformity are important factors influencing the comfort of the office lighting environment. Thus, designing automatic control systems to regulate lighting is essential. This study addresses the issue of natural glare by proposing a method that uses a genetic algorithm (GA) to optimize a backpropagation (BP) neural network model. The model predicts the angle of window slats, with the Sun altitude and azimuth angles as inputs, and the slat angle as the output. For artificial lighting control, a linear function is proposed to manage the relationship between work plane illuminance, natural light intensity, occupancy rates, adjacent luminaire illuminance, and the dimming factor (K). The optimal K value for each luminaire is determined using the least squares method in MATLAB. The intelligent lighting system transmits dimming factors via a ZigBee tree network structure to achieve target illuminance levels. The system’s effectiveness is validated through simulations in DIAlux software, demonstrating that the workplace illuminance in occupied areas reaches 500 lx, while, in unoccupied areas, it reaches 300 lx, with an illuminance uniformity greater than 0.7. This addresses the issue of low illuminance uniformity during daytime. Additionally, the lighting power densities (LPDs) of 1.53 W/m2 and 3.8 W/m2 are well below the specified threshold of 6 W/m2, indicating significant energy savings while maintaining compliance with office lighting standards.

Dielectric discharge of PI material irradiated by 40 MeV-protons

Deep dielectric charging and discharging by electrons has been known for years. However, deep space missions towards the Moon, Mars and Jupiter have developed these years. In these space environments, spacecrafts would expose in high fluxes of solar energetic protons which demands the understanding of charging and discharging mechanism by protons. In this paper, dielectric breakdown of polyimide(PI) material irradiated by 40 MeV-protons was studied. Discharge of PI materials with different thicknesses of 21.5mm, 15.5mm, 13.6mm and 8.2mm were investigated. For PI films with thickness of 21.5mm, 15.5mm, and 13.6mm, proton discharges were firstly triggered as the protons reached integral fluxes of 1.2×1012p/cm2,2.7×1012p/cm2 and 1.2×1012p/cm2, respectively. No discharge was achieved for PI film with 8.2mm thickness. Besides, discharge events originated by secondary electrons were also achieved during irradiation.On the other hand, the internal potential and electric field was also simulated using simulation of internal charging software for 3D (SIC3D). Simulation results indicate that discharge threshold caused by protons is decided by two factors: the internal electric field and the length of discharge path. After irradiated by protons, a thicker material might store more protons and produce stronger internal electric field, but might also has a longer discharge path. The integral proton flux required for discharging was 1012p/cm2 which is extremely high in real space conditions, and proton discharge may not happen immediately after irradiated by energetic protons in space. But the stored protons can produce a localized electric field and might be triggered during the next space radiation events like the solar energetic particle (SEP) events or the bursts of energetic electrons (BEE) events.

Model Order Reduction and Stability Enhancement Control for AC/DC Converters Through State Feedback Method

In the DC distribution networks, DC bus voltage is maintained by the grid-connected converter; the controllability and reliability of the grid-connected converter significantly affect the bus voltage characteristic. To address the problem of limited stability and frequent oscillations, this paper proposes a state feedback control method for the AC/DC converter. Conventional AC/DC converter adopts the voltage-current double-closed-loop control structure with the proportional-integral (PI) controllers, which is the equivalent of the typical type II control system, but the typical type II control system cannot fully settle the stability and immunity problems. In contrast, the state feedback control strategy not only achieves the control objectives of the traditional double-closed-loop control but also reduces the AC/DC converter system model to a typical Type I system, which improves stability and thus enhances the oscillation suppression capability of the bus voltage. By selecting multiple state variables and designing the converter pole configuration range, the proposed single-loop state feedback control method manages to optimize both the dynamic and steady-state performances of the grid-connected AC/DC converter. Finally, the effectiveness of the proposed single-loop state feedback control strategy is verified through MATLAB (2018b)/Simulink software simulation and experiments on a DC distribution network platform.

Broadband Subcarrier Signals Based on AWG-RoF Network: A Software Simulation

Radio-over-fiber is emerging as a progressively significant technology within the wireless in-building market. Identifying dynamic range requirements and determining the optimal laser option is crucial for this particular application. Hence, this study introduces a revolutionary architecture for the array waveguide grating multiplexer (AWG) that utilizes switched radio over fiber technology, offering significant system design, installation, and operation advantages. Prospective developments encompass applying AWG-RoF conveyance to facilitate expected pivotal technologies for future mobile systems, including millimeter-wave transmission and enormous MIMO. The output power ranged between (19.983dBm) and (12.431dBm), the average received noise power (dBm) was (17.117), and the average received power was (17.2425dBm). The simulation demonstrated favorable outcomes, including enhanced bandwidth and transmission range, while experiencing negligible losses.

Simulation of Bruising in Persimmon Under the Dynamic Impact by the Finite Element Method

ABSTRACTPersimmon is a soft fruit, which is why it is one of the horticultural products most prone to mechanical damage throughout the cold chain. Understanding the impact of this damage on the post‐harvest quality of these fruits is extremely important to reduce losses that occur throughout the supply chain. This study used the finite element method (FEM) to predict the damage to persimmon during impact loading. The tensile and puncture tests were used to find mechanical properties, and the pendulum tests for three levels of impact. During simulation, persimmon was modeled as an elastic–plastic, and the problem was considered a non‐linear explicit procedure. Two different force‐time and initial velocity methods were used for simulation in Abaqus software. Results of the maximum von Mises stress, maximum contact force, deformation, bruise volume, and internal energy indicated that increasing the impact level in both methods resulted in a rise of stress, deformation, bruise volume, and absorbed energy. The average error in contact force in the force‐time and initial velocity methods was 12% and 21%, respectively. Also, the average deformation error in the force‐time and initial velocity methods was 10% and 52%, respectively. According to these results, the force‐time method is more accurate, and the elastic–plastic model can properly represent the behavior of persimmon.

Investigating the feasibility of nano-grid infrastructure integration into street lighting systems based on energy production and economic evaluation

To enhance efficient and sustainable energy usage in street lighting systems, a nano-grid infrastructure comprising an energy harvesting, storage, and management system is integrated. This paper investigated the feasibility in terms of energy production and economic evaluation of using various energy harvesting for photovoltaic, piezoelectric, and wind energy in a nano-grid street lighting system. The photovoltaic system was evaluated based on the factors of annual actual solar radiation, power losses, and system performance using the PVsyst software. The piezoelectric energy production was studied and designed. Optimal piezoelectric installation for maximum power generation was analyzed in terms of deformation and stress using ANSYS software. For wind power generation, the wind turbine characteristics, along with its location, were designed to optimize power output using computational fluid dynamic simulations in ANSYS software. After that, economic evaluation for the proposed energy harvesting systems for nano-grid street lighting system are analyzed and compared in terms of DPP, NPV, IRR, and LCOE. In addition, the optimization of using PV, a wind system, a hybrid PV—wind system for nano-grid street lighting systems was conducted using HOMER Pro software. The results indicated that generating power through PV, piezoelectric, and wind energy was feasible. However, economic evaluation unveiled the infeasibility of employing piezoelectric and wind energy systems due to their elevated investment costs relative to their power generation capabilities. The dynamics of power generation from PV and wind systems, along with street lighting consumption, significantly impacted the dimensions of energy harvesting and storage systems, as well as their economic feasibility. The hybrid PV-wind system exhibited strong economic feasibility.

SIMULATION OF MULTITHREADED FURNACE OPERATION PROCESSES

The article discusses the theoretical foundations of simulation modeling, as well as paradigms that include analysis and subsequent selection of the optimal method for solving the problem of visualizing processes taking place in a convection-radiant furnace. The method of discrete-time modeling, its basic concepts and features were considered in more detail. The purpose, general design and principle of operation of a multithreaded furnace were given. A thorough analysis of the technological process was also carried out and the main elements of the system were highlighted, as well as key events that cause changes in the state of the furnace were identified, followed by software simulation of the processes of operation of a multithreaded furnace.