Simulation Design Research Articles

Effect of Physical Properties on Mechanical Behaviors of Sandstone under Uniaxial and Triaxial Compressions.

Mechanical properties of sandstone, such as compressive strength and young's modulus, are commonly used in the design of geotechnical structures and numerical simulation of underground reservoirs using models such as the digital groundwater, equivalent porous medium, and Discrete Fracture Network (DFN) models. A better understanding of the mechanical behaviors of sandstone under different loading conditions is imperative when assessing the stability of geotechnical structures. This paper highlights the effect of the physical properties (i.e., porosity, mean grain size) and environmental conditions (i.e., water content and confining stress) on uniaxial compressive strength, triaxial compressive strength, and young's modulus of sandstone. A series of uniaxial and triaxial compression experiments are conducted on sandstone formations from Wyoming. In addition, experimental data on sandstones from the literature are compiled and integrated into this study. Prediction equations for the compressive strengths and young's modulus of sandstone are established based on commonly available physical properties and known environmental conditions. The results show that the mean Uniaxial Compressive Strength (UCS) decreases as the porosity, water content, and mean grain size increase. Furthermore, a predictive empirical relationship for the triaxial compressive strength is established under different confinements and porosity. The relationship suggests that the mean peak compressive strength increases at a higher confinement and decreases at a higher porosity. The results and recommendations provide a useful framework for evaluating the strength and deformation of most sandstone.

Mechanical Friction Simulation and Optimization Design of Floating Bearing of Mechanical Tricone Bit

This paper aims to find out the most vulnerable position and the suitable clearance ratio of the floating sleeve between the inside and outside floating sleeve of the tricone bit. In this paper, the mechanical analysis model of the drill bit is established to get the simulated working condition of the tri-cone bit, and then the stress condition of the floating bearing is simulated. Finally, the multi-factor variable orthogonal test method is used to optimize the clearance ratio of the floating sleeve. The results show that the simulation results are consistent with the wear position of the floating sleeve: during the operation of the floating sleeve, the most vulnerable position is the edge position, the largest deformation is the opening position, the recommended internal clearance of the floating sleeve is 0.06–0.07 mm, the recommended external clearance is 0.02–0.04 mm, and the recommended internal clearance ratio is 2.0–2.4.

Research and Optimization of the Influence of Process Parameters on Ti Alloys Surface Roughness Using Femtosecond Laser Texturing Technology

One of the major disadvantages of Ti alloys is their poor wear resistance. To increase their wear resistance, before applying a wear-resistant layer, the surface of the substrate should be carefully prepared to ensure the required coating adhesion. Femtosecond laser (fs) texturing is a technology that can be used for surface texturing of Ti alloys because it enables a controlled heat input on a small surface area. The process of laser texturing is very sensitive to the choice of input parameters, such as the number of passes (P) and laser power (W), the choice of which may significantly influence the ultimate surface roughness values (Ra). It cannot be expected that by using the fs process a given default Ra value will be achieved, but it is assumed that the obtained roughness values will be within the given interval. As a result of this research with a significance level of 95% using a design of experiments (DOE) and Monte Carlo simulations, a general linear model of Ra = f (P, W) and optimal input parameter intervals (P and W) of laser texturing were obtained both for the given interval as well as for the default surface roughness value (Ra). Considering that an industrial process is involved here, a process performance capability index (Cpk) has been also defined, which shows that optimal process parameter intervals give roughness values for the given interval or given default roughness value.

Simulation of Weft Knitted Fabric Using Three-DimensionalYarn Loops and Grid and Spring Mass Models

The existing knitted fabric simulation methods cannot be effectively applied to three-dimensional (3D) modeling and simulation of weft knitted garments due to the lack of simple and convenient 3D dynamic simulation models for weft knitted fabrics. This paper presents a method of constructing a loop model by coupling the grid model with the spring mass model. The simulation of weft knitted fabric with real effects was achieved through the coupled model construction of the loop model combined with the yarn simulation generation algorithm and yarn collision response algorithm. The method presented in this paper can quickly and simply simulate the design of weft knitted clothing with loop structure. It provides a reference for the 3D simulation design of weft knitted fabric.

Numerical simulation and new controller design of steerable nano-mirror in ionic liquid electrolytes

This research aims to create a novel controller for micro/nano-systems (sensors and actuators) operating in ionic liquid media. To illustrate the capability of the proposed controller based on numerical simulation, the controller’s impacts on a nano-mirror immersed in ionic liquid media are analyzed. Based on the modified couple stress theory, a two-degree-of-freedom descriptive formulation is developed to more precisely investigate the size-dependent dynamic performance of nano-mirrors. Also, nano-mirror physics is extended by employing resistive fluid as a continuum substance ranging from light to dense. Utilizing the lattice Boltzmann method, the dynamic performance of the nano-mirror is studied. Considering numerical results, a new model-based self-adaptive controller is designed and added to the system. Furthermore, a classical controller is designed. Finally, the advantages of the proposed methodology are compared with the results of classical control methods employed in such systems, for which a numerical model of the system’s dynamic behavior is developed.

Disability Simulation Design and Implementation in Adapted Physical Activity Coursework – Reports from Faculty

ABSTRACT Despite wide use in adapted physical activity (APA) courses, disability simulations are heavily critiqued for not being culturally responsive and for perpetuating negative stigmas. The present study explored the extent to which critiques have been addressed. Specifically, we aimed to appraise the design of disability simulations. A convenience sample of 14 APA instructors were surveyed and 8 opted-in for follow-up, semi-structured interviews. Adopting a pragmatic, interpretivist lens, we critically evaluated course artifacts and instructors’ descriptions of their assignments. Four assignment types were identified: evaluating accessibility of facilities, experiencing adaptations for activities of daily living, participating in disability sport, and practicing effective teaching modifications. While instructors agreed on a general definition of disability simulations, they were often hesitant to identify their assignments as such, especially disability sport-types. As teacher-researchers, who ourselves employ disability simulations in our courses, we confronted this ambiguity to explore implications for our teaching practices.

A simulation study on the utility of the Structured Interview of Reported Symptoms-Second Edition (SIRS-2) in Taiwan Region adults

ABSTRACT The Structured Interview of Reported Symptoms (SIRS) and its revised edition (SIRS-2) are frequently used in forensic psychological evaluations for assessing response style. The present research investigated the utility of this instrument in Taiwan Region adults. In a simulation design, 143 nonclinical volunteers were randomly assigned to either simulating or honest-responding groups. Results indicated that the primary scales of the Chinese SIRS-2 possessed acceptable internal consistency and generated large to very large effect sizes (1.39–2.17) in differentiating simulators and genuine respondents. The convergent validity of the Chinese SIRS-2 was supported by the correlations of its scales with the Chinese MMPI-2 validity scales. Confirmatory factor analysis results showed a one-factor model. The decision models of both the SIRS and SIRS-2 resulted in few to no false positives, while the SIRS had greater sensitivity than the SIRS-2. The SIRS-2 total score generated discrimination rates comparable to the published manual in detecting feigning or honest responding. Results supported the use of the Chinese SIRS-2 in Taiwan Region adults. However, as the research methodology inflates both effect sizes and specificity estimates, further research is needed to examine the clinical utility of the Chinese SIRS-2.

A pattern catalog for augmenting Digital Twin models with behavior

Abstract Digital Twins are emerging as a solution to build and extend existing software systems to make better use of data produced by physical systems. For supporting the development of Digital Twins, several software vendors are offering dedicated tool support, often referred to as Digital Twin platforms. The modeling capabilities of these platforms are mostly concerned with structural viewpoints, i.e., providing an overview of available components including their current and historical sensor values. However, behavioral viewpoints did not yet receive much attention on these platforms. As behavioral models are often used during the design processes, e.g., for simulation and synthesis, it would be beneficial for having them included in Digital Twin platforms, e.g., for reasoning on the set of possible next actions or for checking the execution history to perform runtime validation. In this paper, we present a catalog of modeling patterns for augmenting Digital Twin models with behavioral models and their corresponding runtime information without requiring any extension of the code bases of Digital Twin platforms. We demonstrate the presented modeling patterns by applying them to the Digital Twin platform offered by Microsoft, in an additive manufacturing use case of a 3D printer in a production line.

Resonance Control System of a Vortex Wind Turbine for Energy Generation through Structural Redesign

The consumption of electrical energy is increasing due to problems related to the deficient energy supply in certain localities, which affects the basic needs in rural communities where, currently, the efforts to distribute electricity by the authorities, through common technologies, are not enough. On the other hand, there is also the problem of the overexploitation of non-renewable energies, which produce large amounts of C02. To reduce these problems, renewable energies that do not generate polluting waste are used, but the ability of engineers is needed to achieve prototypes that give good results. The purpose of this research is to carry out the design and simulation of a control system and redesign of a Vortex wind turbine mast to keep it in resonance and generate electrical energy. The study objectives are met by verifying the specific results through requirements analysis, simulation design, and system validation. As a result, the parameters to generate vortices and keep the system in resonance were identified. In addition, the redesign of the mast of the Vortex wind turbine was obtained.

Stop, collaborate, and listen: Encouraging interprofessional education through critical care simulations for pharmacy students

AbstractThe ability to work effectively on an interprofessional team is a key skill for pharmacy students, especially in the critical care setting. Successful interprofessional teamwork between pharmacists and the health care team has been shown to improve patient outcomes. Subsequently, early exposure to interprofessionalism in the critical care setting may benefit student pharmacist confidence and performance prior to advanced hospital rotations. Simulation training offers an ideal, low‐risk educational methodology for student pharmacists to practice key skills. To describe changes in student pharmacist confidence in pharmacotherapy interventions and interprofessional skills using team‐based critical care simulations. Teams of two student pharmacists and six student physicians executed two simulated cases of myocardial infarction and emergent hypertension under the auspices of a physician resident or senior student physician. After diagnosis by the student physicians, student pharmacists consulted on treatment decisions including drug selection, dose, and frequency. Confidence in clinical skills and interprofessionalism were assessed via an unvalidated, pre‐ and post‐simulation survey unique to each profession. Questions were a combination of free responses and a five‐point Likert scale. A total of 105 students participated in the simulations with 26 student pharmacists and 79 student physicians. After the simulations, student pharmacist confidence in their pharmacotherapy knowledge of emergent hypertension and myocardial infarctions (p < 0.02) improved; however, their confidence in effectively communicating with their physician counterparts did not increase significantly (p = 0.06). Student physician confidence in the pharmacist's role during codes increased (p < 0.001), which coincided with student pharmacists' feeling respected and included by the physician team. Interprofessional simulations can supplement critical care exposure and pharmacotherapy education for student pharmacists and student physicians. The simulation design discussed in this report can provide pharmacy educators with a model for implementing team‐based critical care scenarios within pharmacotherapy or foundational professional skills curricula.

A framework for the design of sustainable multi-input second-generation biorefineries through process simulation: A case study for the valorization of lignocellulosic and starchy waste from the plantain agro-industry

The plantain agro-industry generates different residues in the harvest and post-harvest stages. Therefore, new processes for its valorization are required. The aim of this research was to propose a general methodological framework for the design and analysis of multi-input biorefineries for the valorization of residues with a high content of lignocellulosic and starchy materials. This approach was based on the independent processing of the starchy and lignocellulosic materials in the first steps of the biorefinery and relies on process simulation and hierarchic process design procedures. A case study for the design of a multi-input biorefinery for the valorization of residues from the plantain agro-industry was performed by applying the framework proposed. The biorefinery was simulated using SuperPro Designer software. The results obtained suggest that the best alternative for the valorization of plantain residues under Colombian conditions corresponded to the following distribution of key residues: 100% leaf sheaths processed into the natural fiber production section, and 25% peels and 25% rachis processed into the starch extraction and liquefaction section; with this distribution, an NPV of $21,348,000 can be achieved. This work shows that waste from the plantain agro-industry exhibits high potential as a feedstock for the production of value-added products.

Harmonic injection of domestic nonlinear loads in Ghana's power distribution system: analysis and mitigation using a low-cost notch filter

Due to global efforts to save energy, digital light processing (DLP) and direct view televisions (DVTVs) are being replaced by energy-efficient liquid crystal display (LCD) and light emitting diode (LED) televisions. However, these energy-efficient appliances cause harmonics to be injected into the power distribution system, posing a threat to power quality. This study investigates the harmonics generated by common domestic appliances, particularly LCD and LED TVs used in homes in Ghana. Field harmonic measurements were taken using a C.A. 8335 Power Quality Analyzer at a selected facility and were then replicated in a simulation using MATLAB/SIMULINK to model the facility's area network capacity of 100-kVA, 11kV/433V. The study proposes a notch filter as a harmonic mitigation technique, which is integrated into the simulation design and found to be effective at reducing total harmonic distortion current to 0.05 % when applied in parallel to nonlinear loads. The study also compares the harmonic distortion generated by LED TVs and LCD TVs, finding that both types generate high levels of distortion.

Design of a Direct numerical Simulation of flow and heat transfer in a T-junction

Several investigations have been undertaken to study the velocity and temperature fields associated with the thermal mixing between fluids, and resulting thermal striping in a T-junction. However, the available experimental databases are not sufficient to describe the involved physics in adequate detail, and, due to experimental limitations, accurate data on velocity and temperature fluctuations in regions close to the wall are not available. Computational Fluid Dynamics (CFD) can play an important role in predicting such complex flow features. However, predicting complex thermal fatigue phenomena is a challenge for the available momentum and heat flux turbulence models. Furthermore, such models need to be extensively validated.The aim of the present work is to design a reference numerical experiment for Direct Numerical Simulation (DNS) of a thermal fatigue scenario using Reynolds-Averaged Navier-Stokes (RANS) simulations. First, the feasibility of scaling down the Reynolds number from experimental cases to a computationally-feasible range is investigated. The junction corner shape is also modified to a slightly rounded corner, ensuring that the underlying fundamental physical phenomena of turbulence and thermal mixing flow features are preserved. Finally, the pipe lengths of the model were calibrated to ensure there would be no interference of the upstream developing region and the outlet boundary conditions on the thermal mixing at the junction. A sample under-resolved DNS case, with unity and low-Prandtl number passive temperature scalars, with iso-temperature, iso-flux and mixed (Robin) wall boundary conditions, are presented. This proof-of-concept simulation contributes to the finalization of the set-up for fully-resolved DNS with respect to the computational grid size selection and transient characteristics.

A Practical Guide to Negotiation Simulation Writing

There are many good reasons for writing negotiation simulations, but designing and preparing simulations that generate desired pedagogical effects is a challenging process. Building on an earlier article in this journal that presented fundamental principles for the design of negotiation simulations, this article offers a practical guide that outlines in detail how negotiation simulations can be structured and what elements they should include. We offer blueprints for creating six types of simulations: short introductory, distributive, integrative, multi‐issue, multiparty, and multiparty multi‐issue. For each type of simulation, we suggest the pedagogical use, discuss the basics of the construction, and present the core elements schematically: parties, decision problem, interests, and options. Finally, we illustrate the different types of negotiation simulations with representative examples.

Numerical simulation and optimization design of the landmine blast protection package

The finite element model is established based on the bench test of the landmine blast protection package. The effect of the air gap between the landmine blast protection package and the base plate as well as the stiffness of the package on the deformation of the base plate are investigated. Aluminum sandwich landmine blast protection packages are designed and the effects on the deformation suppression of the base plate are studied using the finite element model. The results show that the air gap is not conducive to the deformation suppression of the base plate. Increasing the stiffness of the package is of benefit to the deformation suppression of the base plate, however, it is necessary to consider the influence of the corresponding increase in thickness of the package on the possible increase in the base plate deformation. The scheme, composed of one piece of 2024-T3 aluminum plate and two pieces of 7mm armored steel, is the best solution among the six aluminum sandwich schemes.

Performance Improvement of Helix Traveling- Wave Tubes Based on Multiobjective Optimization Technique

An optimization design tool for helix traveling-wave tubes (TWTs) is developed by combining the nondominated sorting genetic algorithm II (NSGA-II) and the beam–wave interaction simulator (BWIS), which can realize multiobjective optimization of various TWT figures of merit (FoMs). FoMs include the output power, gain, efficiency, and nonlinear distortion characteristics. This optimization design tool can automatically construct a Pareto-optimal solution set according to FoMs. Then, the final simulation design can be obtained by analyzing the output power variation over the operating band of the individuals in the optimized solution set. In order to ensure the comprehensiveness and accuracy of FoMs, a workflow is established in the optimization tool, which can simulate the physical process by transferring the data between different computing tasks automatically during the design of beam–wave interaction. Based on this design tool, the performance of an L-band helix TWT has been improved significantly. For the demonstrated interaction, the output power, phase distortion, interaction, and recovery efficiency are taken as objectives. After analyzing the output power variation over the operating band, the final parameter set is determined from the Pareto-optimal solution set.

Study on initiation of flyer driven by laser ignition

In order to study the initiation technology of laser ignition driven flyer, the initiation principle of laser ignition driven flyer is analyzed. The velocity simulation design of laser ignition driven flyer and the velocity simulation of different flyers driven by the same charge are carried out with Autodyn, and the initiation verification test of laser ignition driven flyer is carried out. The test results show that RDX can be initiated by impact, and the effect consistency is good, Therefore, using HMX to drive the flyer to impact and detonate RDX has high reliability.

Research on Transmission Efficiency Optimization of WPT System

In this paper, a Buck converter is designed to make the transmission of WPT stable and not susceptible to load changes. This converter ensures the stability of the load end by changing the duty cycle, so that the WPT always works efficiently. The hardware structure design and program design of the converter are discussed in this paper, and the correctness of the design is verified by the simulation design of PSIM.

Fake Happy = Happy? Residual Effect of Feigning and Positive Response Bias

Residual effect of feigning pertains to the findings that individuals, first instructed to feign symptoms, later endorse those symptoms despite being told to respond honestly. We explored whether the same effect would occur if participants were instructed to fabricate positive experiences, such as happiness, by employing a simulation design that included two groups and two testing sessions. The control group received instructions to respond honestly, and the “fake happy” had a task to identify with an exceptionally happy person depicted in a vignette. During Session 1, all participants received the Subjective Happiness Scale, the Satisfaction with Life Scale, and the Supernormality Scale-Revised. In Session 2, after eight days, all participants responded honestly to the Scale of Positive and Negative Experiences and the Flourishing Scale. Overall, fake happy participants, when compared to the control group, exhibited higher levels of supernormality (i.e., positive response bias) and well-being in Session 1. Hence, the instructions had an immediate effect on one’s self-presentation. Yet, the two groups did not differ in Session 2, indicating that the residual effect of feigning was not depicted, or was not strong enough to persist the 8-day period between the sessions. Looking within both groups, all participants significantly lowered their well-being scores overtime. Limitations and implications of this work are discussed.

Design of Broadband High-Efficiency DPA for 5G Micro Base Station

To meet the requirements of the 5G communication system, the Doherty power amplifier has become a research hotspot because of its peak-to-average ratio and high backoff efficiency. At the same time, with the continuous development of mobile communication technology, the traditional Doherty power amplifier has gradually been difficult to meet the needs due to its structural problems. On the one hand, due to the limitation of the 1/4 wavelength transmission line in the traditional Doherty power amplifier, it is difficult to achieve broadband. This paper uses the post-matching technology to remove the 1/4 wavelength transmission line to achieve broadband matching. On the other hand, in response to energy conservation and emission reduction, there is a growing demand to reduce power consumption in base stations. In this design, a harmonic suppression network is introduced at the output matching end to further improve the efficiency of the Doherty power amplifier. Finally, the asymmetric structure is introduced to further improve the efficiency of the power amplifier. Main and auxiliary power amplifier transistors select Cree CGH40010F and CGH40025 respectively. Based on the ADS simulation design and test, a broadband high-efficiency Doherty amplifier working in a 3.3~3.6 GHz band is designed for a 5G communication base station. The maximum saturated output power is 44.5 dBm and the drain efficiency is 67%~73%. When power fallback is 8 dB, the drain efficiency is 43%~51%.