Modified robust optimal adaptive control for flight environment simulation system with heat transfer uncertainty

To solve the rapid transient control problem of Flight Environment Simulation System(FESS) of Altitude Ground Test Facilities(AGTF) with large heat transfer uncertainty and disturbance, a new adaptive control structure of modified robust optimal adaptive control is presented.The mathematic modeling of FESS is given and the influence of heat transfer is analyzed through energy view. To consider the influence of heat transfer in controller design, we introduce a matched uncertainty that represents heat transfer influence in the linearized system of FESS. Based on this linear system, we deduce the design of modified robust optimal adaptive control law in a general way. Meanwhile, the robust stability of the modified robust optimal adaptive control law is proved through using Lyapunov stability theory. Then, a typical aero-engine test condition with Mach Dash and Zoom-Climb is used to verify the effectiveness of the devised adaptive controller. The simulation results show that the designed controller has servo tracking and disturbance rejection performance under heat transfer uncertainty and disturbance;the relative steady-state and dynamic errors of pressure and temperature are both smaller than 1% and 0.2% respectively. Furthermore,the influence of the modification parameter c is analyzed through simulation. Finally, comparing with the standard ideal model reference adaptive controller, the modified robust optimal adaptive controller obviously provides better control performance than the ideal model reference adaptive controller does.

Energy and long-term hygrothermal performance of building enclosures based on dynamic environmental simulation test

Dynamic environmental testing is an effective means to study the energy and long-term hygrothermal performance of building enclosures. Southeast University is designing and building a large-scale dynamic environment simulation testing facility. It can simuhaneously and dynamically simulate temperature, relative humidity, infrared solar radiation, UV radiation, and precipitation. A transformation is needed to predict the energy and long-term hygrothermal performance of building enclosures under real service conditions using data obtained from accelerated tests.

Environmental simulation platform and its application to geodesic instruments for a performance study

In this study,an environmental simulation platform(ETS-02)was constructed for high-precision geodesic instruments(e.g.,absolute/relative gravimeters and inclinometers),to test the disturbances caused by environmental fl uctuations.The outer layer of the platform was constructed with two sets of rectangular electromagnetic coils,which generated the required magnetic fi eld when current was applied.The inner layer was a closed cabin in which radiators were distributed such that the temperature of the experimental space inside the cabin could be controlled,by energy exchange between the radiators and a thermal controller through the fl owing liquid.A high-precision hexapod was used to simulate the tilt-related eff ect.The platform was capable of adjusting temperatures within a dynamic range of 0℃-70℃ at a resolution of 0.01℃.The noise of the power-spectrum density when the cabin was set to room temperature was measured as 0.03℃/Hz^(1/2) at 1 mHz.The magnetic field simulation had a dynamic range of±300μT and stability of 20 nT.The resolution of the ground-tilt simulation was 1 arc s.The inner space of the platform had a volume of approximately 5 m^(3),which is sufficient for most types of instruments to be tested for a general environmental coupling effect.To illustrate the application of the platform,a dual-axis inclinometer was built and tested carefully with the platform,and the accuracy of the calibration factors was found to be signifi cantly improved.

Simulation Environments: Challenges for Advancement

A brief review of the basic terminology on simulation, simulation life-cycle activities such as model-based activities, behavior-oriented activities, and quality assurance activities is given. Then, the challenges and opportunities for the advancement of the state-of-the-art in simulation environments are discussed under the following headings: modelling environments, simulation environments, mixed simulation environments, and comprehensive simulation environments.

A Simulation Environment for Intrusion Detection System in IEC 61850 Based Substation Automation System

Greater complexity and interconnectivity across systems embracing electrical power technologies has meant that cyber-security issues have attracted significant attention. In this paper a simulation environment for intrusion detection system in IEC 61850 standard-based substation automation system is provided to test simulated attacks on IEDs （intelligent electronic devices）. Intrusion detection is the process of detecting malicious attacker, so it is an effective and mature security mechanism to protect electrical facility. However, it is not harnessed when securing IEC 61850 automated substation. To prove the detection capability of the system testing environment was developed to analyze and test attacks simulated with different test cases. It shows that the simulation environment works accordingly to various network traffic scenarios and eventually proves the functionality of intrusion detection system to be later deployed in the real IEC 61850 based substation automation system site.

The Design of a Graphical User Environment for Numerical Simulation of Powder Forming Processes

As computer simulation increasingly supports engine er ing design and manufacture, the requirement for a computer software environment providing an integration platform for computational engineering software increas es. A key component of an integrated environment is the use of computational eng ineering to assist and support solutions for complex design. Computer methods fo r structural, flow and thermal analysis are well developed and have been used in design for many years. Many software packages are now available which provi de an advanced capability. However, they are not designed for modelling of powde r forming processes. This paper describes the powder compaction software (PCS_SU T), which is designed for pre- and post-processing for computational simulatio n of the process compaction of powder. In the PCS_SUT software, the adaptive analysis of transient metal powder forming process is simulated by the finite element method based on deformation theories . The error estimates and adaptive remeshing schemes are applied for updated co -ordinate analysis. A generalized Newmark scheme is used for the time domain di scretization and the final nonlinear equations are solved by a Newton-Raphson p rocedure. An incremental elasto-plastic material model is used to simulate the compaction process. To describe the constitutive model of nonlinear behaviour of powder materials, a combination of Mohr-Coulomb and elliptical yield cap model is applied. This model reflects the yielding, frictional and densification char acteristics of powder along with strain and geometrical hardening which occurs d uring the compaction process. A hardening rule is used to define the dependence of the yield surface on the degree of plastic straining. A plasticity theory for friction is employed in the treatment of the powder-tooling interface. The inv olvement of two different materials, which have contact and relative movement in relation to each other, must be considered. A special formulation for friction modelling is coupled with a material formulation. The interface behaviour betwee n the die and the powder is modelled by using an interface element mesh. In the present paper, we have demonstrated pre- and post-processor finite elem ent software, written in Visual Basic, to generate the graphical model and visua lly display the computed results. The software consist of three main part: · Pre-processor: It is used to create the model, generate an app ropriate finite element grid, apply the appropriate boundary conditions, and vie w the total model. The geometric model can be used to associate the mesh with th e physical attributes such as element properties, material properties, or loads and boundary conditions. · Analysis: It can deal with two-dimensional and axi-symmetric applications for linear and non-linear behaviour of material in static and dyna mic analyses. Both triangular and quadrilateral elements are available in the e lement library, including 3-noded, 6-noded and 7-noded (T6B1) triangles and 4 -noded, 8-noded and 9-noded quadrilaterals. The direct implicit algorithm bas ed on the generalized Newmark scheme is used for the time integration and an aut omatic time step control facility is provided. For non-linear iteration, choice s among fully or modified Newton-Raphson method and quasi-Newton method, using the initial stiffness method, Davidon inverse method or BFGS inverse method, ar e possible. · Post-processor: It provides visualization of the computed resu lts, when the finite element model and analysis have been completed. Post-proce ssing is vital to allow the appropriate interpretation of the completed results of the finite element analysis. It provides the visual means to interpret the va st amounts of computed results generated. Finally, the powder behaviour during the compaction of a multi-level component is numerically simulated by the PCS_SUT software, as shown in Fig.1. The predict ive compaction forces at different displacements are computed and compared with the available experimental

Nano-Electronic Simulation Software (NESS): A Novel Open-Source TCAD Simulation Environment

This paper presents the latest status of the open source advanced TCAD simulator called Nano-Electronic Simulation Software(NESS)which is currently under development at the Device Modeling Group of the University of Glasgow.NESS is designed with the main aim to provide an open,flexible,and easy to use simulation environment where users are able not only to perform numerical simulations but also to develop and implement new simulation methods and models.Currently,NESS is organized into two main components:the structure generator and a collection of different numerical solvers;which are linked to supporting components such as an effective mass extractor and materials database.This paper gives a brief overview of each of the components by describing their main capabilities,structure,and theory behind each one of them.Moreover,to illustrate the capabilities of each component,here we have given examples considering various device structures,architectures,materials,etc.at multiple simulation conditions.We expect that NESS will prove to be a great tool for both conventional as well as exploratory device research programs and projects.

The Application of Computer Simulation Technology in Building Design

From the simulation software selection, meteorological data collection, model, boundary conditions, calculation setting and evaluation indicators, the paper summarize simulation method of wind, light and sound, summarize three kinds of environmental. The paper study on optimization analysis method of green building from four aspects of building orientation, architectural form, architectural layout and indoor environment, and puts forward the optimization scheme of the typical simulation analysis of simple questions; provide guidance for optimizing the design of green building. Finally, ECOTECT can adapt to the current domestic engineering design and consulting on green building simulation and design requirements, and has a broad application prospect.

Optimal design of vegetation in residential district with numerical simulation and field experiment

Vegetation plays a key role in improving wind environment of residential districts,and is helpful for creating a comfortable and beautiful living environment.The optimal design of vegetation for wind environment improvement in winter was investigated by carrying out field experiments in Heqingyuan residential area in Beijing,and after that,numerical simulation with SPOTE(simulation platform for outdoor thermal environment) experiments for outdoor thermal environment of vegetation was adopted for comparison.The conclusions were summarized as follows:1) By comparing the experimental data with simulation results,it could be concluded that the wind field simulated was consistent with the actual wind field,and the flow distribution impacted by vegetation could be accurately reflected;2) The wind velocity with vegetation was lower than that without vegetation,and the wind velocity was reduced by 46%;3) By adjusting arrangement and types of vegetation in the regions with excessively large wind velocity,the pedestrian-level wind velocity could be obviously improved through the simulation and comparison.

Role of simulation in training the next generation of endoscopists

The use of simulation based training in endoscopy hasbeen increasingly described,simulation has the potential reduce the harm caused to patients by novicesperforming procedures,increase efficiency by reducingthe time needed to train in the clinical environment andincrease the opportunity to repeatedly practice rareprocedures as well as allowing the assessment of performance.Simulators can consist of mechanical devices,employ cadaveric animal tissue or use virtual realitytechnology.Simulators have been used to teach upperand lower gastrointestinal endoscopy as well as interventional procedures.This review reviews the currentlyavailable endoscopic simulators,and the evidence fortheir efficacy,demonstrating that the ability of simulators to differentiate between novice and expert endoscopists is well established.There is limited evidencefor improved patient outcome as a result of simulationtraining.We also consider how the environment withinwhich a simulation is placed can be manipulated toalter the learning achieved,broadening the scope ofsimulation to develop communication as well as technical skills.Finally the implications for future practice areconsidered; technology is likely improve the fidelity of simulators,increasing the potential for simulation to improve patient outcomes.The impact of the simulation environment,and the correct place of simulation within the training curriculum are both issues which need addressing.

Classifying the sedimentary environments of the Xincun Lagoon,Hainan Island,by system cluster and principal component analyses

An understanding of the sedimentary environment in relation to its controlling factors is of great importance in coastal geomorphology,ecology,tourism and aquaculture studies.We attempt to deal with this issue,using a case study from the Xincun Lagoon,Hainan Island in southern China.For the study,surficial sediment samples were collected,together with hydrodynamic and bathymetric surveys,during August 2013.Numerical simulation was carried out to obtain high-spatial resolution tidal current data.The sediment samples were analyzed to derive mean grain size,sorting coefficient,skewness and kurtosis,together with the sand,silt and clay contents.The modern sedimentary environments were classified using system cluster and principal component analyses.Grain size analysis reveals that the sediments are characterized by extremely slightly sandy silty mud（ESSSM） and slightly silty sand（SSS）,which are distributed in the central lagoon and near-shore shallow water areas,respectively.Mean grain size varies from 0 to 8.0Ф,with an average of 4.6Ф.The silt content is the highest,i.e.,52% on average,with the average contents of sand and clay being 43% and 5%,respectively.There exists a significant correlation between mean size and water depth,suggesting that the surficial sediments become finer with increasing water depth.Cluster analyses reveals two groups of samples.The first group is characterized by mean grain size of more than 5.5Ф,whilst the second group has mean grain size of below 3.5Ф.Further,these groups also have different correlations between mean grain size and the other grain size parameters.In terms of the tidal current,the average values of the root mean square velocity（RMSV） are 7.5 cm/s and 6.9 cm/s on springs and neaps,respectively.For the RMSVs that are higher than 4 cm/s,a significant positive correlation is found between the content of the 63–125 μm fraction and the RMSV,suggesting that the RMSV determines the variability of the very fine sand fraction.Based on system cluster and principal component analyses（PCA）,the modern sedimentary environments are classified into three types according to the grain size parameters,RMSVs and water depth data.The results suggest the importance of grain size parameters and high-spatial resolution hydrodynamic data in differentiating the coastal sedimentary environments.

Corrosion Behavior of Ultra-high Strength Steel 300M in Different Simulated Marine Environments

Corrosion behavior of 300M in neutralcorrosion environments containing Na Clsimulated by totalimmersion（TI）,salt spraying（SS）and periodic immersion（PI）,was investigated by surface analysis techniques,corrosion weight-loss method,and electrochemicalmeasurements.In totalimmersion environment,rust on the steelconsisted of a porous outer rust layer with main constituent of γ-Fe OOH,and an inner rust layer of dense Fe_3O_4 film with network broad cracks.In salt spraying environment,outer rust with main composition of γ-Fe OOH/α-Fe OOH/Fe_3O_4 was compact,and inner rust showed dense Fe_3O_4 film.Rust formed by periodic immersion exhibited a compact outer rust layer with constituent of α-Fe OOH/γ-Fe OOH/Fe_3O_4 and an inner rust layer with composition of α-Fe OOH/α-Fe_2O_3;inner rust showed a ultra-dense film adherent to the steel.The corrosion rate showed a rule of vss（salt spraying）〉vti（totalimmersion）〉〉vpi（periodic immersion）in 0-240 h,and vss≈vti？vpiin 240-720 h.The rust formed by periodic immersion was dense and compact,with stable electrochemicalproperties,and had excellent protection on the steel.Humidity and oxygen concentration in allthe environments played major roles in rust formation.

Online Monitoring Volume Deformation of Cement-based Materials in Multiple Environments

Comparing and analyzing some volume deformation measuring means for cement-based materials at home and abroad, a continuous online monitor of cement-based material volume deformation in multiple environments is developed. The device is designed based on the environmental simulation technology, micro-distance measuring technology of laser and eddy current, and transmission agent online monitoring the deformation of multi-group samples. This device can be used widely, such as glass, ceramics, walling material, and so on, with high precision, low testing cost, and intellectualization.

A Mirror-like ECR Plasma Source for Ionosphere Environment Simulator

A compact mirror-like ECR (electron cyclotron resonance) Plasma source for the ionosphere environment simulator was described for the fort time in China. The Overall sources system was composed of a 200 W 2.45 GHz microwave source, a coastal 3A./4 TEM-mode microwave resonance applicator, column and cylindrical Nd-Fe-P magnets, a quartz bell-shaped discharge chamber, a gas inlet system and a plasma-diffusing bore. The preliminary experiment demonstrated that ambi-polar diffusion plasma stream into the simulator (-500 mm long) formed an environment with following parameters: a plasma density ne of 104 cm-3 - 106 cm-3, an electron temperature Te < 5 eV at a pressure P of 10-1 Pa-10-3 Pa, a Plasma uniformity of > 80% over the experimental target with a 160-mm-in-diameter, satisfying primarily the requirement of simulating in a severe ionosphere environment.

Simulation Operating System and Integrated Simulation Software

In this paper, a new concept of simulation operating system (SIMOS) is described. A detailed definition of SIMOS is given, and two integrated simulation software (IPSOS and IMSS) are introduced based on SIMOS.

China Exported Space Environment Simulator to Russia

In the mid July, 2011, the GVU-600 space environment simulator developed by Bei-jing Institute of Spacecraft Environment Engineering of China Academy of Space Technology (CAST) under China

Effects of Environmental Factors on Corrosion Behavior of E690 Steel in Simulated Marine Environment

The effects of hydrostatic pressure, dissolved oxygen, temperature and flow velocity, and their interaction on the corrosion rates of E690 high-strength steel (HSS) in simulated marine environments were studied using response surface methodology. The results show that the flow velocity exerts the most significant influence on the corrosion rate of E690 HSS. Consequently, the corrosion behavior of E690 HSS under varying flow velocities were analyzed profoundly from initial pitting corrosion to long-term corrosion properties. The results indicate that the flow state facilitates the mass transfer and enhances the adsorption tendency of Cl− by enhancing the electrochemical activity of the steel surface. These factors accelerate the electrochemical reactions, resulting in increased pitting density, depth and the long-term corrosion rates in dynamic seawater environments.

The Erosion Effect of Kapton Film in a Ground-based Atomic Oxygen Irradiation Simulator

In order to investigate the effect of space environmental factors on spacecraft materials, a ground-based simulation facility for space atomic oxygen（AO） irradiation was developed in our laboratory. Some Kapton film samples were subjected to AO beam generated by this facility. The Kapton films before and after AO exposure were analyzed comparatively using optical microscopy, scanning electronic microscopy, atomic force microscopy, high-precision microbalance, and X-ray photoelectron spectroscopy. The experimental results indicate that the transmittance of Kapton film will be reduced by AO irradiation notably, and its color deepens from pale yellow to brown. Surface roughness of the AO-treated sample is already increased obviously after AO irradiation for 5 hours, and exhibits a flannel-like appearance after 15 hours’ exposure in AO beam. The imide rings and benzene rings in kapton molecule are partially decomposed, and some new bonds form during AO irradiation. The mass loss of kapton film increases linearly with the increase of AO fluence, which is resulted from the formation of volatile products, such as CO, CO2 and NOx. The breakage in structure and degradation in properties of AO-treated Kapton film can be attributed to the integrated effect ofimpaction and oxidization of AO beam. The test results agree well with the space flight experimental data.

Development of an Accurate Urban Modeling System Using CAD/GIS Data for Atmosphere Environmental Simulation

This paper presents an urban modeling system using CAD/GIS data for atmosphere environmental simulation, such as wind flow and contaminant spread in urban area. The CAD data is used for the shape modeling for the high-storied buildings and civil structures with complicated shape since the data for that is not included in the 3D-GIS data accurately. The unstructured mesh based on the tetrahedron element is employed in order to express the urban structures with complicated shape accurately. It is difficult to understand the quality of shape model and mesh by the conventional visualization technique. In this paper, the stereoscopic visualization using virtual reality (VR) technology is employed for the verification of the quality of shape model and mesh. The present system is applied to the atmosphere environmental simulation in urban area and is shown to be an useful planning and design tool to investigate the atmosphere environmental problem.

Construction of a macromolecular structural model of Chinese lignite and analysis of its low-temperature oxidation behavior

The aim of this paper is to analyze the change in the active structure of lignite during the process of lowtemperature oxidation by constructing a molecular structure model for lignite. Using quantum computation combined with experimental results of proximate analysis, ultimate analysis, Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS), a structural model for the large molecular structure was constructed. By analyzing the bond lengths in the model molecule, the evolution law for the active structure of lignite was predicted for the process of low-temperature oxidation. In low-temperature oxidation,alkanes and hydroxyls are the primary active structures observed in lignite, though ether may also react. These active functional groups react with oxygen to release heat, thereby speeding up the reaction between coal and oxygen. Finally, the content of various functional groups in the process of lignite low-temperature oxidation was analyzed by infrared analysis, and the accuracy of the model was verified.