Simulation of volute tongue of small-size centrifugal compressor

A high speed and small mass-flow-rate centrifugal compressor with original and modified volute tongue shape was simulated by 3D viscous Navier-Stokes equations.A sharp and a round tongue of volute were modeled to compare their pressure ratios and efficiency characteristics.The flow fields around volute tongues were investigated;the velocity and pressure distributions of volute inlet were studied by unsteady simulation.Static pressure fluctuation near volute tongue was monitored and transformed into amplitude spectrum to identify blade passing frequency influence.The results show that the tongue simplification can cause certain difference on pressure ratio and efficiency.The pressure and velocity distribution of volute inlet indicate obvious circumferential distortion due to volute tongue especially at low mass flow rate.In addition,the static pressure pulsation of volute inlet and the noise level in diffuser and volute increase significantly under low mass flow operating condition.

Two Monte Carlo-based simulators for imaging-system modeling and projection simulation of flat-panel X-ray source

The advantages of a flat-panel X-ray source(FPXS)make it a promising candidate for imaging applications.Accurate imaging-system modeling and projection simulation are critical for analyzing imaging performance and resolving overlapping projection issues in FPXS.The conventional analytical ray-tracing approach is limited by the number of patterns and is not applicable to FPXS-projection calculations.However,the computation time of Monte Carlo(MC)simulation is independent of the size of the patterned arrays in FPXS.This study proposes two high-efficiency MC projection simulators for FPXS:a graphics processing unit(GPU)-based phase-space sampling MC(gPSMC)simulator and GPU-based fluence sampling MC(gFSMC)simulator.The two simulators comprise three components:imaging-system modeling,photon initialization,and physical-interaction simulations in the phantom.Imaging-system modeling was performed by modeling the FPXS,imaging geometry,and detector.The gPSMC simulator samples the initial photons from the phase space,whereas the gFSMC simulator performs photon initialization from the calculated energy spectrum and fluence map.The entire process of photon interaction with the geometry and arrival at the detector was simulated in parallel using multiple GPU kernels,and projections based on the two simulators were calculated.The accuracies of the two simulators were evaluated by comparing them with the conventional analytical ray-tracing approach and acquired projections,and the efficiencies were evaluated by comparing the computation time.The results of simulated and realistic experiments illustrate the accuracy and efficiency of the proposed gPSMC and gFSMC simulators in the projection calculation of various phantoms.

Application of Patient Simulators Combined with Internet plus Scenario Simulation Teaching Models on Intravenous Infusion Nursing Education in China

Objective: To explore the effectiveness of applying patient simulators combined with Internet Plus scenario simulation teaching models on intravenous (IV) infusion nursing education, and to provide scientific evidence for the implementation of advanced teaching models in future nursing education. Methods: Enrolled 60 nurses who took the IV infusion therapy training program in our hospital from January 2022 to December 2023 for research. 30 nurses who were trained in traditional teaching models from January to December 2022 were selected as the control group, and 30 nurses who were trained with simulation-based teaching models with methods including simulated patients, internet, online meetings which can be replayed and scenario simulation, etc. from January to December 2023 were selected as the experimental group. Evaluated the learning outcomes based on the Competency Inventory for Nursing Students (CINS), Problem-Solving Inventory (PSI), comprehensive learning ability, scientific research ability, and proficiency in the theoretical knowledge and practical skills of IV infusion therapy. Nursing quality, the incidence of IV infusion therapy complications and nurse satisfaction with different teaching models were also measured. Results: The scientific research ability, PSI scores, CINS scores, and comprehensive learning ability of the experimental group were better than those of the control group (P 0.05), and their assessment results of practical skills, nursing quality of IV infusion therapy during training, and satisfaction with teaching models were all better than those of the control group with statistical significance (P < 0.05). The incidence of IV infusion therapy complications in the experimental group was lower than that in the control group, indicating statistical significance (P < 0.05). Conclusions: Teaching models based on patient simulators combined with Internet Plus scenario simulation enable nursing students to learn more directly and practice at any time and in any place, and can improve their proficiency in IV infusion theoretical knowledge and skills (e.g. PICC catheterization), core competencies, problem-solving ability, comprehensive learning ability, scientific research ability and the ability to deal with complicated cases. Also, it helps provide high-quality nursing education, improve the nursing quality of IV therapy, reduce the incidence of related complications, and ensure the safety of patients with IV therapy.

Transurethral resection of bladder tumor: A systematic review of simulator-based training courses and curricula

Objective:Transurethral resection of bladder tumor is one of the most common everyday urological procedures.This kind of surgery demands a set of skills that need training and experience.In this review,we aimed to investigate the current literature to find out if simulators,phantoms,and other training models could be used as a tool for teaching urologists.Methods:A systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses statement and the recommendations of the European Association of Urology guidelines for conducting systematic reviews.Fifteen out of 932 studies met our inclusion criteria and are presented in the current review.Results:The UroTrainer(Karl Storz GmbH,Tuttlingen,Germany),a virtual reality training simulator,achieved positive feedback and an excellent face and construct validity by the participants.The inspection of bladder mucosa,blood loss,tumor resection,and procedural time was improved after the training,especially for inexperienced urologists and medical students.The construct validity of UroSim®(VirtaMed,Zurich,Switzerland)was established.SIMBLA simulator(Samed GmbH,Dresden,Germany)was found to be a realistic and useful tool by experts and urologists with intermediate experience.The test objective competency model based on SIMBLA simulator could be used for evaluating urologists.The porcine model of the Asian Urological Surgery Training and Education Group also received positive feedback by the participants that tried it.The Simulation and Technology Enhanced Learning Initiative Project had an extraordinary face and content validity,and 60%of participants would like to use the simulators in the future.The 5-day multimodal training curriculum“Boot Camp”in the United Kingdom achieved an increase of the level of confidence of the participants that lasted months after the project.Conclusion:Simulators and courses or curricula based on a simulator training could be a valuable learning tool for any surgeon,and there is no doubt that they should be a part of every urologist's technical education.

NeTrainSim:a network-level simulator for modeling freight train longitudinal motion and energy consumption

Although train modeling research is vast, most available simulation tools are confined to city-or trip-scale analysis, primarily offering micro-level simulations of network segments. This paper addresses this void by developing the Ne Train Sim simulator for heavy long-haul freight trains on a network of multiple intersecting tracks. The main objective of this simulator is to enable a comprehensive analysis of energy consumption and the associated carbon footprint for the entire train system. Four case studies were conducted to demonstrate the simulator's performance. The first case study validates the model by comparing Ne Train Sim output to empirical trajectory data. The results demonstrate that the simulated trajectory is precise enough to estimate the train energy consumption and carbon dioxide emissions. The second application demonstrates the train-following model considering six trains following each other. The results showcase the model ability to maintain safefollowing distances between successive trains. The next study highlights the simulator's ability to resolve train conflicts for different scenarios. Finally, the suitability of the Ne Train Sim for modeling realistic railroad networks is verified through the modeling of the entire US network and comparing alternative powertrains on the fleet energy consumption.

Blast waveform tailoring using controlled venting in blast simulators and shock tubes

A critical challenge of any blast simulation facility is in producing the widest possible pressure-impulse range for matching against equivalent high-explosive events.Shock tubes and blast simulators are often constrained with the lack of effective ways to control blast wave profiles and as a result have a limited performance range.Some wave shaping techniques employed in some facilities are reviewed but often necessitate extensive geometric modifications,inadvertently cause flow anomalies,and/or are only applicable under very specific configurations.This paper investigates controlled venting as an expedient way for waveforms to be tuned without requiring extensive modifications to the driver or existing geometry and could be widely applied by existing and future blast simulation and shock tube facilities.The use of controlled venting is demonstrated experimentally using the Advanced Blast Simulator(shock tube)at the Australian National Facility of Physical Blast Simulation and via numerical flow simulations with Computational Fluid Dynamics.Controlled venting is determined as an effective method for mitigating the impact of re-reflected waves within the blast simulator.This control method also allows for the adjustment of parameters such as tuning the peak overpressure,the positive phase duration,and modifying the magnitude of the negative phase and the secondary shock of the blast waves.This paper is concluded with an illustration of the potential expanded performance range of the Australian blast simulation facility when controlled venting for blast waveform tailoring as presented in this paper is applied.

Molecular simulation study of the microstructures and properties of pyridinium ionic liquid[HPy][BF_(4)]mixed with acetonitrile

The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this work.The following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution function.The results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient decreases.Additionally,the excess molar volume initially decreases,reaches a minimum,and then increases.The rules of radial distribution functions(RDFs)of characteristic atoms are different.With increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then decreases.This indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.

Müller cells are activated in response to retinal outer nuclear layer degeneration in rats subjected to simulated weightlessness conditions

A microgravity environment has been shown to cause ocular damage and affect visual acuity,but the underlying mechanisms remain unclear.Therefore,we established an animal model of weightlessness via tail suspension to examine the pathological changes and molecular mechanisms of retinal damage under microgravity.After 4 weeks of tail suspension,there were no notable alterations in retinal function and morphology,while after 8 weeks of tail suspension,significant reductions in retinal function were observed,and the outer nuclear layer was thinner,with abundant apoptotic cells.To investigate the mechanism underlying the degenerative changes that occurred in the outer nuclear layer of the retina,proteomics was used to analyze differentially expressed proteins in rat retinas after 8 weeks of tail suspension.The results showed that the expression levels of fibroblast growth factor 2(also known as basic fibroblast growth factor)and glial fibrillary acidic protein,which are closely related to Müller cell activation,were significantly upregulated.In addition,Müller cell regeneration and Müller cell gliosis were observed after 4 and 8 weeks,respectively,of simulated weightlessness.These findings indicate that Müller cells play an important regulatory role in retinal outer nuclear layer degeneration during weightlessness.

基于simulator+技术的动态驾驶安全教育系统

交通事故频发已经严重影响到了人们的生活,并对社会经济造成了巨大的损失。提升驾驶员的驾驶能力能有效减少驾驶事故发生。聚焦典型违法驾驶行为,基于simulator实验平台开发的沉浸体验式教育系统(DSIES),通过系统教育纠正驾驶行为进而减少事故。通过典型违法驾驶行为致因分析,基于计划行为理论提出"知-教-行"动态教育系统。为验证系统有效性,选取具有代表性的4项违法驾驶行为作为实验对象,42名被试者被随机均分为2组进行传统教育及新型教育。采用描述性统计、显著性方差分析及灰度关联分析方法验证不同教育方式的效果。实验结果表明,新型教育系统能有效提升驾驶员驾驶能力;但随着时间的流逝,教育效果均有所降低。另一方面,该教育系统从短时教育及长时教育效果方面均优于传统教育,通过动态教育系统能有效提高驾驶员危险预测能力、降低交通违法行为。

基于OPNET Simulator的低压电力线载波通信路由算法仿真

为了提高低压电力线载波通信的可靠性,以基于传输矩阵的动态路由算法为例,探讨基于OPNET Simulator的低压电力线载波通信路由算法。探讨数据帧设计、进程建模、节点建模和网络结构建模的方法,由仿真结果可以分别确定创建传输矩阵所需时间与传输速率和节点数量之间的关系。

可视化软件包Power World Simulator在电力系统教学中的应用

介绍一种先进的电力系统仿真软件Power World Simulator,其以潮流分析为核心,采用动画式多色彩的单线图可视化技术,模拟电力系统在给定时间段内的运行状况,从而直观、生动地阐述电力系统的基本概念,是辅助教学的有力工具。

仿真软件POWER WORLD SIMULATOR在电力系统分析课程中的应用

电力系统分析课程中有些概念抽象,不容易通过实际演示来完成,使得本门课程教与学都变得困难起来。采用具有可视化图形用户界面的Power World Simulator软件,可以很好地解决这些问题。文章介绍了这款全英文免费的软件,根据一个14节点电力系统原型,建立了可视化的模型,使用该软件演示了潮流计算和短路计算等难点问题,显示了该软件给电力系统分析课程教与学带来的好处。

基于Forest Simulator BWINPro的云南松林经营模拟分析

以云南省一平浪林场为研究对象,以Forest Simulator BWINPro为工作平台,通过建立云南松等主要造林树种的生长模型数据库,实现20年生云南松林动态生长经营模拟。结果表明:该模拟系统可以无缝衔接多树种的林分生长和收获模型,对云南松林生长经营从单木和林分两个层面进行可视化展示。应用森林经营模拟技术,可实现林分生长以及未来状态的可视化模拟,实现林分动态监测,为不同时期云南松林经营管理提供参考。

The System Design of Semiconductor Device Simulator

This paper studies the numerical simulation for semiconductor devices and discusses the software design of the simulation system. Our focus is on the deep submicron device simulation for BJT, MOSFET, heterojunction bipolar transistors (HBT), etc. So the object oriented technology for software design and its realization is used to make the system easy to implement, maintain and extend. Besides the discussion of simulation and software system design, this paper introduces a device simulator SMDS and its parallel extension under local network environment using CORBA technology.

Visual System Simulator平台下锁相环综合分析与仿真

给出了基于VSS平台的锁相环仿真过程,并将其引入课堂教学和实验。同时给出了锁相环的仿真模型,构建了完整的锁相环系统,并给出了仿真波形与环路滤波器设计方法。实践证明,采用这种方式可以帮助学生对相关内容的理解,并为今后进行系统设计工作打下良好的基础。

PowerWorld Simulator电力系统仿真可视化软件包的功能及应用

美国伊利诺伊大学电气及计算机工程学院开发的PowerWorld Simulator电力系统仿真可视化软件可直观形象地显示电力系统的运行情况.用户可以建立、更改各种电力系统模型及参数,在仿真器中进行各种操作,从而对模型进行潮流分析、故障分析及经济运行分析等.阐述仿真器强大的功能和操作简易的特点,并与其他仿真软件进行比较,通过在PowerWorld Simulator中实现仿真算例,分析比较仿真结果,证明了PowerWorld Simulator的准确性,以及在电力系统行业的应用前景.

Optimum Design of Impedance Simulator for Phased Array Antnnas

The impedance of a solid state active phased array antenna varing with frequency and beam scanning scanning angle be matched with the solid state active matching network (SSAMN). In order to adjust and measure the radar conveniently and Securely, it is necessary for the impedance of the simulator of the phased array antennas to be optimized.Having selected the PIN dilde controlling circuits and the circuit parameters optimized,the simulator circuit is determined through numerical computation The experiment is given in support of the simulation.

TMS320C54x Simulator文件格式及其应用

详细介绍了TMS320C54x Simulator环境的文件格式及其文件加载步骤,以及如何将BMP或JPEG格式灰度图像转换为能够使TMS320C54x Simulator识别的格式文件。实例应用表明此方法能够将图像信息加载到TMS320C54x Simulator环境中,进行相应的图像处理。

P2PSimulator:一个通用P2P协议模拟器

点对点(Peer-to-Peer,P2P)技术作为分布式系统领域的一个新的热门技术,已经取得众多的研究成果。但是预想中的标准性基础构架系统并没有出现,研究者们设计了多种不同的协议,在不同的环境下进行试验,使得各个协议之间难以进行公平的对比评价。该文从自身的需要出发,设计并实现了一个通用的P2P协议模拟器P2PSimulator,一个跨平台、高效、支持蒙特卡罗方法、支持多种协议、高度可配置的通用模拟器框架,希望能够改变这种状况。

Graphical Simulator for Chinese Ink-Wash Drawing

Simulating the traditional painting art by computer graphics is a challenging and attractive subject. Basing on the experience in the ink wash drawing, in this paper, we expound the artistic characters of ink wash painting and particularly analyze the characteristics of the materials used in the ink wash drawing and the relationships between them. A simulation model is presented and some typical visual effects of the ink wash painting are realized.