WorldWideScience

Sample records for aero thermal parameters

  1. On the precision of aero-thermal simulations for TMT

    Science.gov (United States)

    Vogiatzis, Konstantinos; Thompson, Hugh

    2016-08-01

    Environmental effects on the Image Quality (IQ) of the Thirty Meter Telescope (TMT) are estimated by aero-thermal numerical simulations. These simulations utilize Computational Fluid Dynamics (CFD) to estimate, among others, thermal (dome and mirror) seeing as well as wind jitter and blur. As the design matures, guidance obtained from these numerical experiments can influence significant cost-performance trade-offs and even component survivability. The stochastic nature of environmental conditions results in the generation of a large computational solution matrix in order to statistically predict Observatory Performance. Moreover, the relative contribution of selected key subcomponents to IQ increases the parameter space and thus computational cost, while dictating a reduced prediction error bar. The current study presents the strategy followed to minimize prediction time and computational resources, the subsequent physical and numerical limitations and finally the approach to mitigate the issues experienced. In particular, the paper describes a mesh-independence study, the effect of interpolation of CFD results on the TMT IQ metric, and an analysis of the sensitivity of IQ to certain important heat sources and geometric features.

  2. Aero-Thermal Calibration of the NASA Glenn Icing Research Tunnel (2012 Tests)

    Science.gov (United States)

    Pastor-Barsi, Christine; Allen, Arrington E.

    2013-01-01

    A full aero-thermal calibration of the NASA Glenn Icing Research Tunnel (IRT) was completed in 2012 following the major modifications to the facility that included replacement of the refrigeration plant and heat exchanger. The calibration test provided data used to fully document the aero-thermal flow quality in the IRT test section and to construct calibration curves for the operation of the IRT.

  3. High-Temperature Adhesives for Thermally Stable Aero-Assist Technologies

    Science.gov (United States)

    Eberts, Kenneth; Ou, Runqing

    2013-01-01

    Aero-assist technologies are used to control the velocity of exploration vehicles (EVs) when entering Earth or other planetary atmospheres. Since entry of EVs in planetary atmospheres results in significant heating, thermally stable aero-assist technologies are required to avoid the high heating rates while maintaining low mass. Polymer adhesives are used in aero-assist structures because of the need for high flexibility and good bonding between layers of polymer films or fabrics. However, current polymer adhesives cannot withstand temperatures above 400 C. This innovation utilizes nanotechnology capabilities to address this need, leading to the development of high-temperature adhesives that exhibit high thermal conductivity in addition to increased thermal decomposition temperature. Enhanced thermal conductivity will help to dissipate heat quickly and effectively to avoid temperature rising to harmful levels. This, together with increased thermal decomposition temperature, will enable the adhesives to sustain transient high-temperature conditions.

  4. Aero-thermal analysis of lifting body configurations in hypersonic flow

    Science.gov (United States)

    Kumar, Sachin; Mahulikar, Shripad P.

    2016-09-01

    The aero-thermal analysis of a hypersonic vehicle is of fundamental interest for designing its thermal protection system. The aero-thermal environment predictions over several critical regions of the hypothesized lifting body vehicle, including the stagnation region of the nose-cap, cylindrically swept leading edges, fuselage-upper, and fuselage-lower surfaces, are discussed. The drag (Λ=70°) and temperature (Λ=80°) minimized sweepback angles are considered in the configuration design of the two hypothesized lifting body shape hypersonic vehicles. The main aim of the present study is to analyze and compare the aero-thermal characteristics of these two lifting body configurations at same heat capacity. Accordingly, a Computational Fluid Dynamics simulation has been carried out at Mach number (M∞=7), H=35 km altitude with zero Angle of Attack. Finally, the material selection for thermal protection system based on these predictions and current methodology is described.

  5. The Chaotic Prediction for Aero-Engine Performance Parameters Based on Nonlinear PLS Regression

    Directory of Open Access Journals (Sweden)

    Chunxiao Zhang

    2012-01-01

    Full Text Available The prediction of the aero-engine performance parameters is very important for aero-engine condition monitoring and fault diagnosis. In this paper, the chaotic phase space of engine exhaust temperature (EGT time series which come from actual air-borne ACARS data is reconstructed through selecting some suitable nearby points. The partial least square (PLS based on the cubic spline function or the kernel function transformation is adopted to obtain chaotic predictive function of EGT series. The experiment results indicate that the proposed PLS chaotic prediction algorithm based on biweight kernel function transformation has significant advantage in overcoming multicollinearity of the independent variables and solve the stability of regression model. Our predictive NMSE is 16.5 percent less than that of the traditional linear least squares (OLS method and 10.38 percent less than that of the linear PLS approach. At the same time, the forecast error is less than that of nonlinear PLS algorithm through bootstrap test screening.

  6. Modeling simulation of the thermal radiation for high-speed flight vehicles' aero-optical windows

    Science.gov (United States)

    Chen, Lei; Zhang, Liqin; Guo, Mingjiang

    2015-10-01

    When high-speed flight vehicles fly in the atmosphere, they can generate serious aero-optical effect. The optical window temperature rises sharply because of aerodynamic heating. It will form radiation interference that can lead infrared detectors to producing non-uniform radiation backgrounds, decreasing system SNR and detection range. Besides, there exits temperature difference due to uneven heating. Under the thermo-optical and elastic-optical effects, optical windows change into inhomogeneous mediums which influence the ray propagation. In this paper, a model of thermal radiation effect was built by a finite element analysis method. Firstly, the optical window was divided into uniform grids. Then, radiation distribution on the focal planes at different angles of the window's normal line and optical axis was obtained by tracing light rays of each grid. Finally, simulation results indicate that radiation distribution reflects the two directions-the length and width-of temperature distribution, and the change of angle causes the center of radiation distribution to shift to one direction of the image surface under the same window temperature.

  7. Advanced High Temperature Adhesives for Thermally Stable Aero-assist Technologies Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aero-assist technologies are used to control the velocity of exploration vehicles (EV) when entering earth or other planetary atmospheres. Since entry of EVs in...

  8. Research on the aero-thermal effects by 3D analysis model of the optical window of the infrared imaging guidance

    Science.gov (United States)

    Xu, Bo; Li, Lin; Zhu, Ying

    2014-11-01

    Researches on hypersonic vehicles have been a hotspot in the field of aerospace because of the pursuits for higher speed by human being. Infrared imaging guidance is playing a very important role in modern warfare. When an Infrared Ray(IR) imaging guided missile is flying in the air at high speed, its optical dome suffers from serious aero-optic effects because of air flow. The turbulence around the dome and the thermal effects of the optical window would cause disturbance to the wavefront from the target. Therefore, detected images will be biased, dithered and blurred, and the capabilities of the seeker for detecting, tracking and recognizing are weakened. In this paper, methods for thermal and structural analysis with Heat Transfer and Elastic Mechanics are introduced. By studying the aero-thermal effects and aero-thermal radiation effects of the optical window, a 3D analysis model of the optical window is established by using finite element method. The direct coupling analysis is employed as a solving strategy. The variation regularity of the temperature field is obtained. For light with different incident angles, the influence on the ray propagation caused by window deformation is analyzed with theoretical calculation and optical/thermal/structural integrated analysis method respectively.

  9. LSST summit enclosure-facility design optimization using aero-thermal modeling

    Science.gov (United States)

    Sebag, J.; Vogiatzis, K.; Barr, J.; Neill, D.

    2012-09-01

    This paper describes Computational Fluid Dynamic (CFD) analyses combined with thermal analyses for modeling the effects of passive ventilation, enclosure-building configuration and topography on the optical performance of the Large Synoptic Survey Telescope (LSST). The primary purpose of the analyses was to evaluate the seeing contribution of the major enclosure-facility elements and to select the features to be adopted in the baseline design from among various configurations being explored by the LSST project and the contracted architectural design team. In addition, one of several simulations for different telescope orientations is presented including various wind-telescope relative azimuth angles. Using a post-processing analysis, the effects of turbulence and thermal variations within the airflow around the buildings and inside the telescope-enclosure configuration were determined, and the optical performance due to the thermal seeing along the optical path was calculated.

  10. Measurements of thermal parameters of solar modules

    Science.gov (United States)

    Górecki, K.; Krac, E.

    2016-04-01

    In the paper the methods of measuring thermal parameters of photovoltaic panels - transient thermal impedance and the absorption factor of light-radiation are presented. The manner of realising these methods is described and the results of measurements of the considered thermal parameters of selected photovoltaic panels are presented. The influence of such selected factors as a type of the investigated panel and its mounting manner on transient thermal impedance of the considered panels is also discussed.

  11. Least Squares Support Vector Machine Based Real-Time Fault Diagnosis Model for Gas Path Parameters of Aero Engines

    Institute of Scientific and Technical Information of China (English)

    WANG Xu-hui; HUANG Sheng-guo; WANG Ye; LIU Yong-jian; SHU Ping

    2009-01-01

    Least squares support vector machine (LS-SVM) is applied in gas path fault diagnosis for aero engines.Firstly,the deviation data of engine cruise are analyzed.Then,model selection is conducted using pattern search method.Finally,by decoding aircraft communication addressing and reporting system (ACARS) report,a real-time cruise data set is acquired,and the diagnosis model is adopted to process data.In contrast to the radial basis function (RBF) neutral network,LS-SVM is more suitable for real-time diagnosis of gas turbine engine.

  12. Nonlinear Parameter-Varying AeroServoElastic Reduced Order Model for Aerostructural Sensing and Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall goal of the project is to develop reliable reduced order modeling technologies to automatically generate nonlinear, parameter-varying (PV),...

  13. Parameter Uncertainty for Repository Thermal Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hardin, Ernest [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hadgu, Teklu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Greenberg, Harris [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Dupont, Mark [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-01

    This report is one follow-on to a study of reference geologic disposal design concepts (Hardin et al. 2011a). Based on an analysis of maximum temperatures, that study concluded that certain disposal concepts would require extended decay storage prior to emplacement, or the use of small waste packages, or both. The study used nominal values for thermal properties of host geologic media and engineered materials, demonstrating the need for uncertainty analysis to support the conclusions. This report is a first step that identifies the input parameters of the maximum temperature calculation, surveys published data on measured values, uses an analytical approach to determine which parameters are most important, and performs an example sensitivity analysis. Using results from this first step, temperature calculations planned for FY12 can focus on only the important parameters, and can use the uncertainty ranges reported here. The survey of published information on thermal properties of geologic media and engineered materials, is intended to be sufficient for use in generic calculations to evaluate the feasibility of reference disposal concepts. A full compendium of literature data is beyond the scope of this report. The term “uncertainty” is used here to represent both measurement uncertainty and spatial variability, or variability across host geologic units. For the most important parameters (e.g., buffer thermal conductivity) the extent of literature data surveyed samples these different forms of uncertainty and variability. Finally, this report is intended to be one chapter or section of a larger FY12 deliverable summarizing all the work on design concepts and thermal load management for geologic disposal (M3FT-12SN0804032, due 15Aug2012).

  14. Kinetic Parameters of Thermal Degradation of Polymers

    Institute of Scientific and Technical Information of China (English)

    朱新生; 程嘉祺

    2003-01-01

    The derivative expressions between activation energy (E) and the temperature at the maximum mass loss rate(Tmax) and between activation energy (E) and exponent (N) were deduced in the light of Arrhenius theory. It was found that the increase of activation energy results in the decrease of exponent and the increase of Tmax. The kinetic parameters were involved in the analysis of the thermal degradation of several polymers. The degradation kinetics of these polymers well complied with the prediction of the derivative expressions for the polymer degradation with single mechanism dominated.

  15. Quenching parameter in a holographic thermal QCD

    CERN Document Server

    Patra, Binoy Krishna

    2016-01-01

    We have calculated the quenching parameter, $\\hat{q}$ in a model-independent way using the gauge-gravity duality. In earlier calculations, the geometry in the gravity side at finite temperature was usually taken as the pure AdS blackhole metric for which the dual gauge theory becomes conformally invariant unlike QCD. Therefore we use a metric which incorporates the fundamental quarks by embedding the coincident D7 branes in the Klebanov-Tseytlin background and a finite temperature is switched on by inserting a black hole into the background, known as OKS-BH metric. Further inclusion of an additional UV cap to the metric prepares the dual gauge theory to run similar to thermal QCD. Moreover $\\hat{q}$ is usually defined in the literature from the Glauber-model perturbative QCD evaluation of the Wilson loop, which has no reasons to hold if the coupling is large and is thus against the main idea of gauge-gravity duality. Thus we use an appropriate definition of $\\hat{q}$: $\\hat{q} L^- = 1/L^2$, where $L$ is the s...

  16. Quenching parameter in a holographic thermal QCD

    Science.gov (United States)

    Patra, Binoy Krishna; Arya, Bhaskar

    2017-01-01

    We have calculated the quenching parameter, q ˆ in a model-independent way using the gauge-gravity duality. In earlier calculations, the geometry in the gravity side at finite temperature was usually taken as the pure AdS black hole metric for which the dual gauge theory becomes conformally invariant unlike QCD. Therefore we use a metric which incorporates the fundamental quarks by embedding the coincident D7 branes in the Klebanov-Tseytlin background and a finite temperature is switched on by inserting a black hole into the background, known as OKS-BH metric. Further inclusion of an additional UV cap to the metric prepares the dual gauge theory to run similar to thermal QCD. Moreover q ˆ is usually defined in the literature from the Glauber model perturbative QCD evaluation of the Wilson loop, which has no reasons to hold if the coupling is large and is thus against the main idea of gauge-gravity duality. Thus we use an appropriate definition of q ˆ : q ˆ L- = 1 /L2, where L is the separation for which the Wilson loop is equal to some specific value. The above two refinements cause q ˆ to vary with the temperature as T4 always and to depend linearly on the light-cone time L- with an additional (1 /L-) correction term in the short-distance limit whereas in the long-distance limit, q ˆ depends only linearly on L- with no correction term. These observations agree with other holographic calculations directly or indirectly.

  17. Uncertainty Analysis of Thermal Comfort Parameters

    Science.gov (United States)

    Ribeiro, A. Silva; Alves e Sousa, J.; Cox, Maurice G.; Forbes, Alistair B.; Matias, L. Cordeiro; Martins, L. Lages

    2015-08-01

    International Standard ISO 7730:2005 defines thermal comfort as that condition of mind that expresses the degree of satisfaction with the thermal environment. Although this definition is inevitably subjective, the Standard gives formulae for two thermal comfort indices, predicted mean vote ( PMV) and predicted percentage dissatisfied ( PPD). The PMV formula is based on principles of heat balance and experimental data collected in a controlled climate chamber under steady-state conditions. The PPD formula depends only on PMV. Although these formulae are widely recognized and adopted, little has been done to establish measurement uncertainties associated with their use, bearing in mind that the formulae depend on measured values and tabulated values given to limited numerical accuracy. Knowledge of these uncertainties are invaluable when values provided by the formulae are used in making decisions in various health and civil engineering situations. This paper examines these formulae, giving a general mechanism for evaluating the uncertainties associated with values of the quantities on which the formulae depend. Further, consideration is given to the propagation of these uncertainties through the formulae to provide uncertainties associated with the values obtained for the indices. Current international guidance on uncertainty evaluation is utilized.

  18. Numerical model for thermal parameters in optical materials

    Science.gov (United States)

    Sato, Yoichi; Taira, Takunori

    2016-04-01

    Thermal parameters of optical materials, such as thermal conductivity, thermal expansion, temperature coefficient of refractive index play a decisive role for the thermal design inside laser cavities. Therefore, numerical value of them with temperature dependence is quite important in order to develop the high intense laser oscillator in which optical materials generate excessive heat across mode volumes both of lasing output and optical pumping. We already proposed a novel model of thermal conductivity in various optical materials. Thermal conductivity is a product of isovolumic specific heat and thermal diffusivity, and independent modeling of these two figures should be required from the viewpoint of a clarification of physical meaning. Our numerical model for thermal conductivity requires one material parameter for specific heat and two parameters for thermal diffusivity in the calculation of each optical material. In this work we report thermal conductivities of various optical materials as Y3Al5O12 (YAG), YVO4 (YVO), GdVO4 (GVO), stoichiometric and congruent LiTaO3, synthetic quartz, YAG ceramics and Y2O3 ceramics. The dependence on Nd3+-doping in laser gain media in YAG, YVO and GVO is also studied. This dependence can be described by only additional three parameters. Temperature dependence of thermal expansion and temperature coefficient of refractive index for YAG, YVO, and GVO: these are also included in this work for convenience. We think our numerical model is quite useful for not only thermal analysis in laser cavities or optical waveguides but also the evaluation of physical properties in various transparent materials.

  19. Basic Thermal Parameters of Selected Foods and Food Raw Materials

    Directory of Open Access Journals (Sweden)

    Monika Božiková

    2017-01-01

    Full Text Available In general, processing and manipulation with foods and food raw materials have significant influence on their physical properties. The article is focused on thermophysical parameters measurement of selected foods and food raw materials. There were examined thermal conductivity and thermal diffusivity of selected materials. For detection of thermal parameters was used instrument Isomet 2104, which principle of measurement is based on transient methods. In text are presented summary results of thermal parameters measurement for various foods and food raw materials as: granular materials – corn flour and wheat flour; fruits, vegetables and fruit products – grated apple, dried apple and apple juice; liquid materials – milk, beer etc. Measurements were performed in two temperature ranges according to the character of examined material. From graphical relations of thermophysical parameter is evident, that thermal conductivity and diffusivity increases with temperature and moisture content linearly, only for granular materials were obtained non‑linear dependencies. Results shows, that foods and food raw materials have different thermal properties, which are influenced by their type, structure, chemical and physical properties. From presented results is evident, that basic thermal parameters are important for material quality detection in food industry.

  20. In-situ measurements of material thermal parameters for accurate LED lamp thermal modelling

    NARCIS (Netherlands)

    Vellvehi, M.; Perpina, X.; Jorda, X.; Werkhoven, R.J.; Kunen, J.M.G.; Jakovenko, J.; Bancken, P.; Bolt, P.J.

    2013-01-01

    This work deals with the extraction of key thermal parameters for accurate thermal modelling of LED lamps: air exchange coefficient around the lamp, emissivity and thermal conductivity of all lamp parts. As a case study, an 8W retrofit lamp is presented. To assess simulation results, temperature is

  1. In-situ measurements of material thermal parameters for accurate LED lamp thermal modelling

    NARCIS (Netherlands)

    Vellvehi, M.; Perpina, X.; Jorda, X.; Werkhoven, R.J.; Kunen, J.M.G.; Jakovenko, J.; Bancken, P.; Bolt, P.J.

    2013-01-01

    This work deals with the extraction of key thermal parameters for accurate thermal modelling of LED lamps: air exchange coefficient around the lamp, emissivity and thermal conductivity of all lamp parts. As a case study, an 8W retrofit lamp is presented. To assess simulation results, temperature is

  2. Thermal Diffusivity Identification of Distributed Parameter Systems to Sea Ice

    Directory of Open Access Journals (Sweden)

    Liqiong Shi

    2013-01-01

    Full Text Available A method of optimal control is presented as a numerical tool for solving the sea ice heat transfer problem governed by a parabolic partial differential equation. Taken the deviation between the calculated ice temperature and the measurements as the performance criterion, an optimal control model of distributed parameter systems with specific constraints of thermal properties of sea ice was proposed to determine the thermal diffusivity of sea ice. Based on sea ice physical processes, the parameterization of the thermal diffusivity was derived through field data. The simulation results illustrated that the identified parameterization of the thermal diffusivity is reasonably effective in sea ice thermodynamics. The direct relation between the thermal diffusivity of sea ice and ice porosity is physically significant and can considerably reduce the computational errors. The successful application of this method also explained that the optimal control model of distributed parameter systems in conjunction with the engineering background has great potential in dealing with practical problems.

  3. ESTIMATION OF THERMAL PARAMETERS OF POWER BIPOLAR TRANSISTORS BY THE METHOD OF THERMAL RELAXATION DIFFERENTIAL SPECTROMETRY

    Directory of Open Access Journals (Sweden)

    V. S. Niss

    2015-01-01

    Full Text Available Thermal performance of electronic devices determines the stability and reliability of the equipment. This leads to the need for a detailed thermal analysis of semiconductor devices. The goal of the work is evaluation of thermal parameters of high-power bipolar transistors in plastic packages TO-252 and TO-126 by a method of thermal relaxation differential spectrometry. Thermal constants of device elements and distribution structure of thermal resistance defined as discrete and continuous spectra using previously developed relaxation impedance spectrometer. Continuous spectrum, based on higher-order derivatives of the dynamic thermal impedance, follows the model of Foster, and discrete to model of Cauer. The structure of sample thermal resistance is presented in the form of siх-chain electro-thermal RC model. Analysis of the heat flow spreading in the studied structures is carried out on the basis of the concept of thermal diffusivity. For transistor structures the area and distribution of the heat flow cross-section are determined. On the basis of the measurements the thermal parameters of high-power bipolar transistors is evaluated, in particular, the structure of their thermal resistance. For all of the measured samples is obtained that the thermal resistance of the layer planting crystal makes a defining contribution to the internal thermal resistance of transistors. In the transition layer at the border of semiconductor-solder the thermal resistance increases due to changes in the mechanism of heat transfer. Defects in this area in the form of delamination of solder, voids and cracks lead to additional growth of thermal resistance caused by the reduction of the active square of the transition layer. Method of thermal relaxation differential spectrometry allows effectively control the distribution of heat flow in high-power semiconductor devices, which is important for improving the design, improve the quality of landing crystals of power

  4. Modeling, Analysis, and Control of a Hypersonic Vehicle with Significant Aero-Thermo-Elastic-Propulsion Interactions: Elastic, Thermal and Mass Uncertainty

    Science.gov (United States)

    Khatri, Jaidev

    This thesis examines themodeling, analysis, and control system design issues for scramjet powered hypersonic vehicles. A nonlinear three degrees of freedom longitudinal model which includes aero-propulsion-elasticity effects was used for all analyses. This model is based upon classical compressible flow and Euler-Bernouli structural concepts. Higher fidelity computational fluid dynamics and finite element methods are needed for more precise intermediate and final evaluations. The methods presented within this thesis were shown to be useful for guiding initial control relevant design. The model was used to examine the vehicle's static and dynamic characteristics over the vehicle's trimmable region. The vehicle has significant longitudinal coupling between the fuel equivalency ratio (FER) and the flight path angle (FPA). For control system design, a two-input two-output plant (FER - elevator to speed-FPA) with 11 states (including 3 flexible modes) was used. Velocity, FPA, and pitch were assumed to be available for feedback. Aerodynamic heat modeling and design for the assumed TPS was incorporated to original Bolender's model to study the change in static and dynamic properties. De-centralized control stability, feasibility and limitations issues were dealt with the change in TPS elasticity, mass and physical dimension. The impact of elasticity due to TPS mass, TPS physical dimension as well as prolonged heating was also analyzed to understand performance limitations of de-centralized control designed for nominal model.

  5. Structure and Thermal Parameters of Ni20Pd80 Alloy

    Institute of Scientific and Technical Information of China (English)

    S. Ahmad; A.B. Ziya; A. Aziz1; Z.I. Zafar

    2009-01-01

    The structure and thermal parameters of Ni20Pd80 alloy were studied by X-ray diffraction(XRD). The diffraction experiments performed in the temperature range of 308-1100 K revealed that the alloy formed a face centered cubic (fcc) Al-type structure. The temperature dependence of the lattice parameters was investigated by using the Bragg line displacement method showing that the lattice parameter increases with the increase of temperature. The mean linear thermal expansion (MLTE(%)), coefficient of thermal expansion (CTE, α), the characteristic Debye temperature (θD) and mean square amplitudes of vibration were determined from XRD data. The value of Debye temperature was found to be 253 K. It was found that temperature factor was independent of the static displacements.

  6. Important Parameter Groups in Thermal Protection of Polymers

    Directory of Open Access Journals (Sweden)

    John Staggs

    2015-07-01

    Full Text Available The problem of thermal protection is explored for two idiosyncratic reactive systems, namely a sacrificial heat-sink material and an intumescent system where a dynamically evolving insulation layer is produced from an initially thin coating. Relatively simple mathematical models of both systems are proposed that encompass the important physical characteristics of each situation and these models are analysed using a mixture of numerical and analytical techniques. Important dimensionless parameter groups are identified and domains of parameter space where thermal performance is particularly good- or particularly bad- are identified.

  7. Numerical Investigation of Aerodynamic and Aero-Thermal Effects for Hypersonic Vehicles%典型外形高超声速气动力/气动热数值计算研究

    Institute of Scientific and Technical Information of China (English)

    刘毅; 王刚; 叶正寅

    2014-01-01

    Hypersonic flow field has been numerically investigated for two different configurations, to study the aer-odynamic / aero-thermal effects. Simulations were performed using an in-house hybrid unstructured Reynolds-aver-aged Navier-Stokes solver ( HUNS3D) . Four different flux differencing schemes ( central scheme and three upwind schemes AUSM+, AUSM+up, Roe) were employed for spatial discretization. The accuracy of all the schemes was compared with each other and with the available experimental data. Different levels of meshes were generated to in-vestigate the effect of grid resolution. The pressure distribution was not much influenced by the mesh resolution;however the predicted heat flux was greatly affected by the change in the mesh resolution. The shock position has been accurately captured by the Central, AUSM+and AUSM+up schemes. The predicted pressure distribution was in good agreement with the experimental data but some difference was observed in the robustness of flux differencing schemes. The increase in the wall temperature gives rise to flow separation which eventually affects the aerodynamic/ aero-thermal heating. After the separation zone the flow reattachment enhances the surface heat transfer dramatic-ally.%通过数值模拟和理论分析的综合研究,比较了网格密度不同对计算的影响,研究了中心格式和3种迎风格式( AUSM+格式、AUSM+up格式、Roe格式)的计算性能,探讨了壁面温度变化对气动力/气动热计算的影响。结果表明:网格密度变化对气动力计算影响不大,但却在很大程度上影响热流的计算及流动分离的模拟;各空间格式都能准确地计算出流场压力分布,有较高的激波分辨率,但鲁棒性有所差异,其中AUSM+up格式在高超声速流场计算中鲁棒性较好;壁面温度升高会导致所得分离区增大,气动力/气动热分布也会相应发生变化;在分离区后的流动再附会很大程度上增大该区域的热流值。

  8. Experimental Determination Of Soft Wheat Flour Thermal Parameters

    Directory of Open Access Journals (Sweden)

    Božiková Monika

    2015-03-01

    Full Text Available This article focuses on temperature relations of selected thermophysical parameters for soft wheat flour. The main aim of experiment was to determine the thermal conductivity, thermal diffusivity and volume specific heat of soft wheat flour in Slovakia marked as Špeciál 00 Extra. Measurements were performed in laboratory settings. Thermal parameters were measured using the thermal analyser Isomet 2104 with two types of probes - a linear probe and plane probe. Measurement by the linear probe is based on a hot wire method, and measurement by the plane probe is based on a simplified plane source method. Both methods are described in the text. Two types of measurement method were used because of the non-homogenous structure of measured material. All thermophysical parameters were measured during the temperature stabilisation in the temperature interval 5-24 °C. Obtained graphical relations had linear increasing progresses with high values of determination coefficients in all cases. Measurement results showed that measurement method has no significant influence on thermophysical parameters values.

  9. Study on thermodynamic cycle parameter matching for intercooled recuperated aero-engine%间冷回热循环航空发动机参数匹配研究

    Institute of Scientific and Technical Information of China (English)

    龚昊; 王占学; 刘增文

    2012-01-01

    The intercooled and recuperated processes were incorporated into the conventional high bypass turbofan engine thermodynamic cycle. Consequently, the intercooled recuperated aero-engine (IRA) simulation model was built and an overall performance simulation program was developed. Then, analysis on choosing and matching the thermodynamic cycle parameters of IRA was conducted. The result indicates that there are some thermody- namic cycle parameters such as intercooler effectiveness, recuperator effectiveness, bypass intercooling split, pressure ratio assignment between booster and high pressure compressor, overall pressure ratio and bypass ratio, which have significant influence on IRA performance. The turbofan engine performance can be improved with the proper use of intercooling, recuperation and the optimized matching of the thermodynamic cycle parameters.%在常规大涵道比涡扇发动机热力循环基础上增加间冷过程和回热过程,发展了间冷回热循环航空发动机(IRA)的计算模型和相应的性能仿真程序.分析了采用间冷回热技术的分排大涵道比涡扇发动机的热力循环参数选择与匹配.结果表明:间冷度、回热度、外涵道间冷用气量、增压级和高压压气机压比分配、总增压比、涵道比等热力循环参数对IRA的性能有很大影响;合理应用间冷回热技术,并优化发动机热力循环参数匹配可以显著改善发动机的性能.

  10. Rock thermal conductivity as key parameter for geothermal numerical models

    Science.gov (United States)

    Di Sipio, Eloisa; Chiesa, Sergio; Destro, Elisa; Galgaro, Antonio; Giaretta, Aurelio; Gola, Gianluca; Manzella, Adele

    2013-04-01

    The geothermal energy applications are undergoing a rapid development. However, there are still several challenges in the successful exploitation of geothermal energy resources. In particular, a special effort is required to characterize the thermal properties of the ground along with the implementation of efficient thermal energy transfer technologies. This paper focuses on understanding the quantitative contribution that geosciences can receive from the characterization of rock thermal conductivity. The thermal conductivity of materials is one of the main input parameters in geothermal modeling since it directly controls the steady state temperature field. An evaluation of this thermal property is required in several fields, such as Thermo-Hydro-Mechanical multiphysics analysis of frozen soils, designing ground source heat pumps plant, modeling the deep geothermal reservoirs structure, assessing the geothermal potential of subsoil. Aim of this study is to provide original rock thermal conductivity values useful for the evaluation of both low and high enthalpy resources at regional or local scale. To overcome the existing lack of thermal conductivity data of sedimentary, igneous and metamorphic rocks, a series of laboratory measurements has been performed on several samples, collected in outcrop, representative of the main lithologies of the regions included in the VIGOR Project (southern Italy). Thermal properties tests were carried out both in dry and wet conditions, using a C-Therm TCi device, operating following the Modified Transient Plane Source method.Measurements were made at standard laboratory conditions on samples both water saturated and dehydrated with a fan-forced drying oven at 70 ° C for 24 hr, for preserving the mineral assemblage and preventing the change of effective porosity. Subsequently, the samples have been stored in an air-conditioned room while bulk density, solid volume and porosity were detected. The measured thermal conductivity

  11. 齿轮轴承结构参数优化设计%Optimization design for structure parameters of aero gear

    Institute of Scientific and Technical Information of China (English)

    杨振和; 苏振华; 杨卓

    2011-01-01

    研究具有不定参数的齿轮轴承结构振动系统动力特性的可靠性优化设计问题.运用Riccati传递矩阵法的基本理论,构建在单元质量和刚度为不定参数时,以齿轮轴承结构动力响应为目标函数,满足基频和系统结构特征约束的微小齿轮轴承结构优化设计模型,采用Matlab优化工具箱作为优化工具,对系统质量和刚度参数进行优化设计.%The problem is studied of dynamic optimization with the reliability constraint of the frequency for the uncertainty structure parameters of gear bearing. Based on the theory of the perturbation RICCATI transfer matrix method. the structure optimization design model of aviation gear-bearing is developed with considering the unit mass of structure and the stiffness of unit shafts as uncertainty parameters, in which the dynamic response of the structure of gearbearing is taken as objective function and the structure feature is taken as constraint in frequency domain. The optimization design of structure mass and stiffness parameters is based on the optimization Toolbox of Matlab.

  12. Extraphysical parameters of thermal comfort; Thermischer Komfort - die extraphysikalischen Aspekte

    Energy Technology Data Exchange (ETDEWEB)

    Bischof, Wolfgang; Brasche, Sabine [Arbeitsgruppe Raumklimatologie, Institut fuer Arbeits-, Sozial-, Umweltmedizin und -Hygiene, Klinikum der Friedrich-Schiller-Universitaet Jena (Germany); Hellwig, Runa Tabea [Fraunhofer-Institut fuer Bauphysik (IBP) Holzkirchen, Valley (Germany)

    2007-07-15

    Standards define thermal comfort as a function of physical and thermophysiological parameters. From investigations of building related symptoms it is well known that satisfaction with the indoor environment also interacts with extraphysical parameters. Thus, data of 1,497 office workers investigated in phase II of the ProKlimA study have been analysed by multiple logistic regression to find associations between thermal sensation or comfort and potential non-environmental variables. The results show diverse effects: While thermal sensation seems almost independent from non-environmental impacts, thermal comfort and satisfaction with the indoor temperature are significantly associated with building characteristics, demographic and job related variables. From these significant and partly strong interactions we conclude, in case of analyses and assessment of complaints about thermal discomfort relevant non environmental impact factors should be considered. (Abstract Copyright [2007], Wiley Periodicals, Inc.) [German] Der Grad der Zufriedenheit mit den thermischen Umgebungsbedingungen von Aufenthaltsraeumen wird im derzeitigen Normwerk als Funktion physikalischer und thermophysiologischer Parameter ermittelt. Aus Untersuchungen zur Befindlichkeit von Bueroarbeitern ist seit laengerem bekannt, dass die Zufriedenheit mit raumklimatischen Bedingungen auch durch extraphysikalische Variablen beeinflusst wird. Anhand von Daten aus der ProKlimA-Studie wurde untersucht, inwieweit extraphysikalische Variablen das Temperaturempfinden, die thermische Behaglichkeit, die Zufriedenheit mit und die Erwartungshaltung bezueglich der Raumtemperatur beeinflussen. Im Ergebnis multipler logistischer Regressionsanalysen zeigt sich, dass thermisches Empfinden weitgehend unabhaengig von extraphysikalischen Einfluessen ist. Thermische Behaglichkeit und Zufriedenheit jedoch stehen in deutlicher Wechselwirkung mit extraphysikalischen Variablen, zu denen neben demographischen Charakteristika auch

  13. Characteristics of the Thermal Ion Bulk Parameters in the Cleft

    Science.gov (United States)

    Coffey, V. N.; Chandler, M. O.; Moore, T. E.

    1997-01-01

    Bulk parameters for the thermal ions (0.3 to 25 eV) have been derived using data from the Scanning Thermal Ion Composition Spectrometer (STICS) on the Sounding of the Cleft Ion Fountain Energization Region (SCIFER) experiment. The SCIFER rocket was launched into the ionospheric cleft region at 1000 MLT with a maximum altitude of 1450 km. The heated cleft plasma was observed to be H(+) dominated, in sharp contrast with observations of the same region near solar maximum. Regions of particular interest include the sharp, heated equatorward wall of the cleft and highly structured patches of transversely-accelerated ions (TAI). Densities, temperatures and velocities are used to characterize and distinguish these regions and to compare to predicted bulk parameters from candidate heating mechanisms.

  14. A method for the assessment of operational severity for a high pressure turbine blade of an aero-engine

    Science.gov (United States)

    Haslam, Anthony; Abu, Abdullahi; Laskaridis, Panagiotis

    2015-12-01

    This paper provides a tool for the estimation of the operational severity of a high pressure turbine blade of an aero engine. A multidisciplinary approach using aircraft/ engine performance models which provide inputs to a thermo-mechanical fatigue damage model is presented. In the analysis, account is taken of blade size, blade metal temperature distribution, relevant heat transfer coefficients and mechanical and thermal stresses. The leading edge of the blade is selected as the critical part in the estimation of damage severity for different design and operational parameters. The study also suggests a method for production of operational severity data for the prediction of maintenance intervals.

  15. Analysis of the variation of range parameters of thermal cameras

    Science.gov (United States)

    Bareła, Jarosław; Kastek, Mariusz; Firmanty, Krzysztof; Krupiński, Michał

    2016-10-01

    Measured range characteristics may vary considerably (up to several dozen percent) between different samples of the same camera type. The question is whether the manufacturing process somehow lacks repeatability or the commonly used measurement procedures themselves need improvement. The presented paper attempts to deal with the aforementioned question. The measurement method has been thoroughly analyzed as well as the measurement test bed. Camera components (such as detector and optics) have also been analyzed and their key parameters have been measured, including noise figures of the entire system. Laboratory measurements are the most precise method used to determine range parameters of a thermal camera. However, in order to obtain reliable results several important conditions have to be fulfilled. One must have the test equipment capable of measurement accuracy (uncertainty) significantly better than the magnitudes of measured quantities. The measurements must be performed in a controlled environment thus excluding the influence of varying environmental conditions. The personnel must be well-trained, experienced in testing the thermal imaging devices and familiar with the applied measurement procedures. The measurement data recorded for several dozen of cooled thermal cameras (from one of leading camera manufacturers) have been the basis of the presented analysis. The measurements were conducted in the accredited research laboratory of Institute of Optoelectronics (Military University of Technology).

  16. Dependence of thermal conductivity on structural parameters in porous samples

    Science.gov (United States)

    Miettinen, L.; Kekäläinen, P.; Turpeinen, T.; Hyväluoma, J.; Merikoski, J.; Timonen, J.

    2012-03-01

    The in-plane thermal conductivity of porous sintered bronze plates was studied both experimentally and numerically. We developed and validated an experimental setup, where the sample was placed in vacuum and heated while its time-dependent temperature field was measured with an infrared camera. The porosity and detailed three-dimensional structure of the samples were determined by X-ray microtomography. Lattice-Boltzmann simulations of thermal conductivity in the tomographic reconstructions of the samples were used to correct the contact area between bronze particles as determined by image analysis from the tomographic reconstructions. Small openings in the apparent contacts could not be detected with the imaging resolution used, and they caused an apparent thermal contact resistance between particles. With this correction included, the behavior of the measured thermal conductivity was successfully explained by an analytical expression, originally derived for regular structures, which involves three structural parameters of the porous structures. There was no simple relationship between heat conductivity and porosity.

  17. Dependence of thermal conductivity on structural parameters in porous samples

    Directory of Open Access Journals (Sweden)

    L. Miettinen

    2012-03-01

    Full Text Available The in-plane thermal conductivity of porous sintered bronze plates was studied both experimentally and numerically. We developed and validated an experimental setup, where the sample was placed in vacuum and heated while its time-dependent temperature field was measured with an infrared camera. The porosity and detailed three-dimensional structure of the samples were determined by X-ray microtomography. Lattice-Boltzmann simulations of thermal conductivity in the tomographic reconstructions of the samples were used to correct the contact area between bronze particles as determined by image analysis from the tomographic reconstructions. Small openings in the apparent contacts could not be detected with the imaging resolution used, and they caused an apparent thermal contact resistance between particles. With this correction included, the behavior of the measured thermal conductivity was successfully explained by an analytical expression, originally derived for regular structures, which involves three structural parameters of the porous structures. There was no simple relationship between heat conductivity and porosity.

  18. Performance analysis of pin fins with temperature dependent thermal parameters using the variation of parameters method

    Directory of Open Access Journals (Sweden)

    Cihat Arslantürk

    2016-08-01

    Full Text Available The performance of pin fins transferring heat by convection and radiation and having variable thermal conductivity, variable emissivity and variable heat transfer coefficient was investigated in the present paper. Nondimensionalizing the fin equation, the problem parameters which affect the fin performance were obtained. Dimensionless nonlinear fin equation was solved with the variation of parameters method, which is quite new in the solution of nonlinear heat transfer problems. The solution of variation of parameters method was compared with known analytical solutions and some numerical solution. The comparisons showed that the solutions are seen to be perfectly compatible. The effects of problem parameters were investigated on the heat transfer rate and fin efficiency and results were presented graphically.

  19. Aero Fighter - 2D Gaming

    CERN Document Server

    Ahmed, Zeeshan

    2010-01-01

    Designing and developing quality based computer game is always a challenging task for developers. In this paper I briefly discuss aero fighting war game based on simple 2D gaming concepts and developed in C & C++ programming languages, using old bitmapping concepts. Going into the details of the game development, I discuss the designed strategies, flow of game and implemented prototype version of game, especially for beginners of game programming.

  20. Modeling Subducting Slabs: Structural Variations due to Thermal Models, Latent Heat Feedback, and Thermal Parameter

    Science.gov (United States)

    Marton, F. C.

    2001-12-01

    The thermal, mineralogical, and buoyancy structures of thermal-kinetic models of subducting slabs are highly dependent upon a number of parameters, especially if the metastable persistence of olivine in the transition zone is investigated. The choice of starting thermal model for the lithosphere, whether a cooling halfspace (HS) or plate model, can have a significant effect, resulting in metastable wedges of olivine that differ in size by up to two to three times for high values of the thermal parameter (ǎrphi). Moreover, as ǎrphi is the product of the age of the lithosphere at the trench, convergence rate, and dip angle, slabs with similar ǎrphis can show great variations in structures as these constituents change. This is especially true for old lithosphere, as the lithosphere continually cools and thickens with age for HS models, but plate models, with parameters from Parson and Sclater [1977] (PS) or Stein and Stein [1992] (GDH1), achieve a thermal steady-state and constant thickness in about 70 My. In addition, the latent heats (q) of the phase transformations of the Mg2SiO4 polymorphs can also have significant effects in the slabs. Including q feedback in models raises the temperature and reduces the extent of metastable olivine, causing the sizes of the metastable wedges to vary by factors of up to two times. The effects of the choice of thermal model, inclusion and non-inclusion of q feedback, and variations in the constituents of ǎrphi are investigated for several model slabs.

  1. THERMOPHORESIS AND ITS THERMAL PARAMETERS FOR AEROSOL COLLECTION

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.; Apte, M.; Gundel, L.

    2007-01-01

    The particle collection effi ciency of a prototype environmental tobacco smoke (ETS) sampler based on the use of thermophoresis is determined by optimizing the operational voltage that determines its thermal gradient. This sampler’s heating element was made of three sets of thermophoretic (TP) wires 25μm in diameter suspended across a channel cut in a printed circuit board and mounted with collection surfaces on both sides. The separation between the heating element and the room temperature collection surface was determined in a numerical simulation based on the Brock-Talbot model. Other thermal parameters of this TP ETS sampler were predicted by the Brock-Talbot model for TP deposition. From the normalized results the optimal collection ratio was expressed in terms of operational voltage and fi lter mass. Prior to the Brock-Talbot model simulation for this sampler, 1.0V was used arbitrarily. The operational voltage was raised to 3.0V, and the collection effi ciency was increased by a factor of fi ve for both theory and experiment.

  2. Thermophoresis and Its Thermal Parameters for Aerosol Collection

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.; Apte, Michael; Gundel, Lara

    2007-08-01

    The particle collection efficiency of a prototype environmental tobacco smoke (ETS) sampler based on the use of thermophoresis is determined by optimizing the operational voltage that determines its thermal gradient. This sampler's heating element was made of three sets of thermophoretic (TP) wires 25mu m in diameter suspended across a channel cut in a printed circuit board and mounted with collection surfaces on both sides. The separation between the heating element and the room temperature collection surface was determined in a numerical simulation based on the Brock-Talbot model. Other thermal parameters of this TP ETS sampler were predicted by the Brock-Talbot model for TP deposition. From the normalized results the optimal collection ratio was expressed in terms of operational voltage and fi lter mass. Prior to the Brock-Talbot model simulation for this sampler, 1.0V was used arbitrarily. The operational voltage was raised to 3.0V, and the collection effi ciency was increased by a factor of fi ve for both theory and experiment.

  3. Experimental and Numerical Correlation of Impact of Spherical Projectile for Damage Analysis of Aero Engine Component

    Directory of Open Access Journals (Sweden)

    Anuradha Nayak Majila

    2016-03-01

    Full Text Available Studies the impact response of flat Titanium alloy plate against spherical projectile for damage analysis of aero engine components using experimental and finite element techniques. Compressed gas gun has been used to impart speed to spherical projectile at various impact velocities for damage studies. Crater dimensions (diameter and depth obtained due to impact have been compared with finite element results using commercially available explicit finite element method code LS-DYNA. Strain hardening, high strain rate and thermal softening effect along with damage parameters have been considered using modified Johnson-Cook material model of LS-DYNA. Metallographic analysis has been performed on the indented specimen. This analysis is useful to study failure analysis of gas turbine engine components subjected to domestic object damage of gas turbine engine. Defence Science Journal, Vol. 66, No. 2, March 2016, pp. 193-199, DOI: http://dx.doi.org/10.14429/dsj.66.9130

  4. Maintenance Decision Based on Data Fusion of Aero Engines

    Directory of Open Access Journals (Sweden)

    Huawei Wang

    2013-01-01

    Full Text Available Maintenance has gained a great importance as a support function for ensuring aero engine reliability and availability. Cost-effectiveness and risk control are two basic criteria for accurate maintenance. Given that aero engines have much condition monitoring data, this paper presents a new condition-based maintenance decision system that employs data fusion for improving accuracy of reliability evaluation. Bayesian linear model has been applied, so that the performance degradation evaluation of aero engines could be realized. A reliability evaluation model has been presented based on gamma process, which achieves the accurate evaluation by information fusion. In reliability evaluation model, the shape parameter is estimated by the performance degradation evaluation result, and the scale parameter is estimated by failure, inspection, and repair information. What is more, with such reliability evaluation as input variables and by using particle swarm optimization (PSO, a stochastic optimization of maintenance decision for aircraft engines has been presented, in which the effectiveness and the accuracy are demonstrated by a numerical example.

  5. Quantifying non-contact tip-sample thermal exchange parameters for accurate scanning thermal microscopy with heated microprobes

    Science.gov (United States)

    Wilson, Adam A.; Borca-Tasciuc, Theodorian

    2017-07-01

    Simplified heat-transfer models are widely employed by heated probe scanning thermal microscopy techniques for determining thermal conductivity of test samples. These parameters have generally been assumed to be independent of sample properties; however, there has been little investigation of this assumption in non-contact mode, and the impact calibration procedures have on sample thermal conductivity results has not been explored. However, there has been little investigation of the commonly used assumption that thermal exchange parameters are sample independent in non-contact mode, or of the impact calibration procedures have on sample thermal conductivity results. This article establishes conditions under which quantitative, localized, non-contact measurements using scanning thermal microscopy with heated microprobes may be most accurately performed. The work employs a three-dimensional finite element (3DFE) model validated using experimental results and no fitting parameters, to determine the dependence of a heated microprobe thermal resistance as a function of sample thermal conductivity at several values of probe-to-sample clearance. The two unknown thermal exchange parameters were determined by fitting the 3DFE simulated probe thermal resistance with the predictions of a simplified probe heat transfer model, for two samples with different thermal conductivities. This calibration procedure known in experiments as the intersection method was simulated for sample thermal conductivities in the range of 0.1-50 W m-1 K-1 and clearance values in the 260-1010 nm range. For a typical Wollaston wire microprobe geometry as simulated here, both the thermal exchange radius and thermal contact resistance were found to increase with the sample thermal conductivity in the low thermal conductivity range while they remained approximately constant for thermal conductivities >1 W m-1 K-1, with similar trends reported for all clearance values investigated. It is shown that

  6. Parameter Identification Of Multilayer Thermal Insulation By Inverse Problems

    Science.gov (United States)

    Nenarokomov, Aleksey V.; Alifanov, Oleg M.; Gonzalez, Vivaldo M.

    2012-07-01

    The purpose of this paper is to introduce an iterative regularization method in the research of radiative and thermal properties of materials with further applications in the design of Thermal Control Systems (TCS) of spacecrafts. In this paper the radiative and thermal properties (heat capacity, emissivity and thermal conductance) of a multilayered thermal-insulating blanket (MLI), which is a screen-vacuum thermal insulation as a part of the (TCS) for perspective spacecrafts, are estimated. Properties of the materials under study are determined in the result of temperature and heat flux measurement data processing based on the solution of the Inverse Heat Transfer Problem (IHTP) technique. Given are physical and mathematical models of heat transfer processes in a specimen of the multilayered thermal-insulating blanket located in the experimental facility. A mathematical formulation of the IHTP, based on sensitivity function approach, is presented too. The practical testing was performed for specimen of the real MLI. This paper consists of recent researches, which developed the approach suggested at [1].

  7. Thermal Parameter Extraction of a Multilayered System by a Genetic Algorithm

    Science.gov (United States)

    Kuriakose, M.; Depriester, M.; Mascot, M.; Longuemart, S.; Fasquelle, D.; Carru, J. C.; Sahraoui, A. Hadj

    2013-09-01

    Submicron multilayer systems are nowadays used in many common applications such as electronic systems, fuel cells, etc. A knowledge of the layer’s thermal properties are of main interest for thermal management in such systems. Thus, the aim of this study is to investigate thermal parameters of a commercially available multilayered system (Pt-Ti-SiO-Si) using the photothermal radiometry technique. Here, a genetic algorithm is used for extracting thermal parameters of this typical four-layer wafer system. The obtained results can be used as a reference for thermal studies of thin layers coated on the top of such wafers, where they act as a deposition substrate.

  8. Dependence of thermal conductivity on structural parameters in porous samples

    OpenAIRE

    L. Miettinen; Kekäläinen, P; T. Turpeinen; Hyväluoma, J; Merikoski, J.; J. Timonen

    2012-01-01

    The in-plane thermal conductivity of porous sintered bronze plates was studied both experimentally and numerically. We developed and validated an experimental setup, where the sample was placed in vacuum and heated while its time-dependent temperature field was measured with an infrared camera. The porosity and detailed three-dimensional structure of the samples were determined by X-ray microtomography. Lattice-Boltzmann simulations of thermal conductivity in the tomographic reconstructions o...

  9. Inverse transient heat conduction problems and identification of thermal parameters

    Science.gov (United States)

    Atchonouglo, K.; Banna, M.; Vallée, C.; Dupré, J.-C.

    2008-04-01

    This work deals with the estimation of polymers properties. An inverse analysis based on finite element method is applied to identify simultaneously the constants thermal conductivity and heat capacity per unit volume. The inverse method algorithm constructed is validated from simulated transient temperature recording taken at several locations on the surface of the solid. Transient temperature measures taped with infrared camera on polymers were used for identifying the thermal properties. The results show an excellent agreement between manufacturer and identified values.

  10. Extraction of thermal parameters of microbolometer infrared detectors using electrical measurement

    Science.gov (United States)

    Karunasiri, R. P. G.; Xu, Gu; Chen, G. X.; Sridhar, U.

    1998-10-01

    The performance of microbolometer infrared sensors is typically characterized by its thermal time constant, heat capacitance, and thermal conductance. Therefore, the determination of these parameters accurately and efficiently is of considerable interest for the design and operation of microbolometer infrared sensors. Usually, the thermal time constant is obtained by measuring the frequency response of microbolometers under infrared excitation and the thermal conductance and capacity are extracted using electrical measurement. In this paper, a technique is described to extract all three parameters using a single electrical measurement. In the measurement, we have employed a Wheatstone Bridge consisting of a bolometer and three reference resistors. The resistance of the bolometer changes as a result of self-heating under an external bias which in turn generates an output voltage across the Bridge. The time dependence of the output voltage was used to extract thermal parameters of the bolometer. We believe this technique is useful in determining the thermal parameters of microbolometer based sensors.

  11. Experimental and Numerical Investigation of Design Parameters for Hydronic Embedded Thermally Active Surfaces

    DEFF Research Database (Denmark)

    Marcos-Meson, Victor; Pomianowski, Michal Zbigniew; E. Poulsen, Søren

    2015-01-01

    This paper evaluates the principal design parameters affecting the thermal performance of embedded hydronic Thermally Active Surfaces (TAS), combining the Response Surface Method (RSM) with the Finite Elements Method (FEM). The study ranks the combined effects of the parameters on the heat flux...

  12. Fully Coupled Aero-Thermochemical-Elastic Simulations of an Eroding Graphite Nozzle

    Science.gov (United States)

    Blades, E. L.; Reveles, N. D.; Nucci, M.; Maclean, M.

    2017-01-01

    A multiphysics simulation capability has been developed that incorporates mutual interactions between aerodynamics, structural response from aero/thermal loading, ablation/pyrolysis, heating, and surface-to-surface radiation to perform high-fidelity, fully coupled aerothermoelastic ablation simulations, which to date had been unattainable. The multiphysics framework couples CHAR (a 3-D implicit charring ablator solver), Loci/CHEM (a computational fluid dynamics solver for high-speed chemically reacting flows), and Abaqus (a nonlinear structural dynamics solver) to create a fully coupled aerothermoelastic charring ablative solver. The solvers are tightly coupled in a fully integrated fashion to resolve the effects of the ablation pyrolysis and charring process and chemistry products upon the flow field, the changes in surface geometry due to recession upon the flow field, and thermal-structural analysis of the body from the induced aerodynamic heating from the flow field. The multiphysics framework was successfully demonstrated on a solid rocket motor graphite nozzle erosion application. Comparisons were made with available experimental data that measured the throat erosion during the motor firing. The erosion data is well characterized, as the test rig was equipped with a windowed nozzle section for real-time X-ray radiography diagnostics of the instantaneous throat variations for deducing the instantaneous erosion rates. The nozzle initially undergoes a nozzle contraction due to thermal expansion before ablation effects are able to widen the throat. A series of parameters studies were conducted using the coupled simulation capability to determine the sensitivity of the nozzle erosion to different parameters. The parameter studies included the shape of the nozzle throat (flat versus rounded), the material properties, the effect of the choice of turbulence model, and the inclusion or exclusion of the mechanical thermal expansion. Overall, the predicted results match

  13. Spatial-temporal-covariance-based modeling, analysis, and simulation of aero-optics wavefront aberrations.

    Science.gov (United States)

    Vogel, Curtis R; Tyler, Glenn A; Wittich, Donald J

    2014-07-01

    We introduce a framework for modeling, analysis, and simulation of aero-optics wavefront aberrations that is based on spatial-temporal covariance matrices extracted from wavefront sensor measurements. Within this framework, we present a quasi-homogeneous structure function to analyze nonhomogeneous, mildly anisotropic spatial random processes, and we use this structure function to show that phase aberrations arising in aero-optics are, for an important range of operating parameters, locally Kolmogorov. This strongly suggests that the d5/3 power law for adaptive optics (AO) deformable mirror fitting error, where d denotes actuator separation, holds for certain important aero-optics scenarios. This framework also allows us to compute bounds on AO servo lag error and predictive control error. In addition, it provides us with the means to accurately simulate AO systems for the mitigation of aero-effects, and it may provide insight into underlying physical processes associated with turbulent flow. The techniques introduced here are demonstrated using data obtained from the Airborne Aero-Optics Laboratory.

  14. Experimental approach for thermal parameters estimation during glass forming process

    Science.gov (United States)

    Abdulhay, B.; Bourouga, B.; Alzetto, F.; Challita, C.

    2016-10-01

    In this paper, an experimental device designed and developedto estimate thermal conditions at the Glass / piston contact interface is presented. This deviceis made of two parts: the upper part contains the piston made of metal and a heating device to raise the temperature of the piston up to 500 °C. The lower part is composed of a lead crucible and a glass sample. The assembly is provided with a heating system, an induction furnace of 6 kW for heating the glass up to 950 °C.The developed experimental procedure has permitted in a previous published study to estimate the Thermal Contact ResistanceTCR using the inverse technique developed by Beck [1]. The semi-transparent character of the glass has been taken into account by an additional radiative heat flux and an equivalent thermal conductivity. After the set-up tests, reproducibility experiments for a specific contact pressure have been carried outwith a maximum dispersion that doesn't exceed 6%. Then, experiments under different conditions for a specific glass forming process regarding the application (Packaging, Buildings and Automobile) were carried out. The objective is to determine, experimentallyfor each application,the typical conditions capable to minimize the glass temperature loss during the glass forming process.

  15. Monitoring the Thermal Parameters of Different Edible Oils by Using Thermal Lens Spectrometry

    Science.gov (United States)

    Jiménez-Pérez, J. L.; Cruz-Orea, A.; Lomelí Mejia, P.; Gutierrez-Fuentes, R.

    2009-08-01

    Several vegetable edible oils (sunflower, canola, soya, and corn) were used to study the thermal diffusivity of edible oils. Thermal lens spectrometry (TLS) was applied to measure the thermal properties. The results showed that the obtained thermal diffusivities with this technique have good agreement when compared with literature values. In this technique an Ar+ laser and intensity stabilized He-Ne laser were used as the heating source and probe beam, respectively. These studies may contribute to a better understanding of the physical properties of edible oils and the quality of these important foodstuffs.

  16. Determination of optimum thermal debinding and sintering process parameters using Taguchi Method

    CSIR Research Space (South Africa)

    Seerane, M

    2015-07-01

    Full Text Available from a green body after injection moulding; failure to completely remove the binder components results in distortion, cracking, blisters and contamination at elevated temperatures. This study focuses on optimising thermal debinding process parameters...

  17. House thermal model parameter estimation method for Model Predictive Control applications

    NARCIS (Netherlands)

    van Leeuwen, Richard Pieter; de Wit, J.B.; Fink, J.; Smit, Gerardus Johannes Maria

    2015-01-01

    In this paper we investigate thermal network models with different model orders applied to various Dutch low-energy house types with high and low interior thermal mass and containing floor heating. Parameter estimations are performed by using data from TRNSYS simulations. The paper discusses results

  18. House thermal model parameter estimation method for Model Predictive Control applications

    NARCIS (Netherlands)

    van Leeuwen, Richard Pieter; de Wit, J.B.; Fink, J.; Smit, Gerardus Johannes Maria

    In this paper we investigate thermal network models with different model orders applied to various Dutch low-energy house types with high and low interior thermal mass and containing floor heating. Parameter estimations are performed by using data from TRNSYS simulations. The paper discusses results

  19. Statistical parameters of thermally driven turbulent anabatic flow

    Science.gov (United States)

    Hilel, Roni; Liberzon, Dan

    2016-11-01

    Field measurements of thermally driven turbulent anabatic flow over a moderate slope are reported. A collocated hot-films-sonic anemometer (Combo) obtained the finer scales of the flow by implementing a Neural Networks based in-situ calibration technique. Eight days of continuous measurements of the wind and temperature fluctuations reviled a diurnal pattern of unstable stratification that forced development of highly turbulent unidirectional up slope flow. Empirical fits of important turbulence statistics were obtained from velocity fluctuations' time series alongside fully resolved spectra of velocity field components and characteristic length scales. TKE and TI showed linear dependence on Re, while velocity derivative skewness and dissipation rates indicated the anisotropic nature of the flow. Empirical fits of normalized velocity fluctuations power density spectra were derived as spectral shapes exhibited high level of similarity. Bursting phenomenon was detected at 15% of the total time. Frequency of occurrence, spectral characteristics and possible generation mechanism are discussed. BSF Grant #2014075.

  20. Physiological parameters for thermal stress in dairy cattle

    Directory of Open Access Journals (Sweden)

    Vanessa Calderaro Dalcin

    Full Text Available ABSTRACT The objective of this study was to investigate changes in physiological parameters of dairy cows and understand which physiological parameters show greater reliability for verification of heat stress. Blood samples were collected for analysis and included hematocrit (Ht, erythrocyte count (ERY, and hemoglobin count (HEMO. In addition, physiological variables, including rectal temperature (RT, heart rate (HR, respiratory rate (RR, and panting score (PS were recorded in 38 lactating cows. These varied according to genetic group (1/2, 3/4, and pure bred Holstein (HO. Analysis of variance considering the effects of genetic group, days, and their interaction as well as linear and quadratic effect of the black globe humidity index (BGHI was performed, as well as broken-line regression. These values were higher in pure HO than in 3/4 and 1/2 groups. The average BGHI during the morning was 74, when 70, 43, and 13% of pure HO, 3/4, and 1/2, respectively, presented RR above reference value. The RR was the best indicator of heat stress and its critical value was 116 breaths/min for 1/2, 140 for 3/4, and 168 breaths/min for pure HO cows. In the HO group, physiological variables increased linearly with BGHI, without presenting inflection in the regression. The inflection point occurred at a higher BGHI for the 1/2 group compared with the other groups. Hematocrit and HEMO were different among genetic groups and did not vary with BGHI, showing that stress was not sufficient to alter these hematological parameters. The 1/2 HO group was capable of maintaining normal physiological parameters for at least 3 BGHI units above that of HO and 1 to 3 units higher than 3/4 HO for RR and RT, respectively. Respiratory rate is the physiological parameter that best predicts heat stress in dairy cattle, and the 1/2 Holstein group is the best adapted to heat stress.

  1. Optimization of Heat Exchangers for Intercooled Recuperated Aero Engines

    Directory of Open Access Journals (Sweden)

    Dimitrios Misirlis

    2017-03-01

    Full Text Available In the framework of the European research project LEMCOTEC, a section was devoted to the further optimization of the recuperation system of the Intercooled Recuperated Aero engine (IRA engine concept, of MTU Aero Engines AG. This concept is based on an advanced thermodynamic cycle combining both intercooling and recuperation. The present work is focused only on the recuperation process. This is carried out through a system of heat exchangers mounted inside the hot-gas exhaust nozzle, providing fuel economy and reduced pollutant emissions. The optimization of the recuperation system was performed using computational fluid dynamics (CFD computations, experimental measurements and thermodynamic cycle analysis for a wide range of engine operating conditions. A customized numerical tool was developed based on an advanced porosity model approach. The heat exchangers were modeled as porous media of predefined heat transfer and pressure loss behaviour and could also incorporate major and critical heat exchanger design decisions in the CFD computations. The optimization resulted in two completely new innovative heat exchanger concepts, named as CORN (COnical Recuperative Nozzle and STARTREC (STraight AnnulaR Thermal RECuperator, which provided significant benefits in terms of fuel consumption, pollutants emission and weight reduction compared to more conventional heat exchanger designs, thus proving that further optimization potential for this technology exists.

  2. Estimation of the Processing Parameters in Electron Beam Thermal Treatments

    Directory of Open Access Journals (Sweden)

    DULAU Mircea

    2014-05-01

    Full Text Available Electron beam have many special properties which make them particularly well suited for use in materials handling through melting, welding, surface treatment, etc., taking into account that this manufacturing is performed in vacuum. The use of electron beam for surface limited heat treatment of workpiece has brought about a noticeable extension of the beam technologies. Some theoretical aspects and simulation results are presented in this paper, considering a high power electron beam processing system and Matlab facilities. This paper can be used in power engineering and electro-technologies fields as a guideline, in order to simulate and analyse the process parameters.

  3. Evaluation of Perfusion and Thermal Parameters of Skin Tissue Using Cold Provocation and Thermographic Measurements

    Directory of Open Access Journals (Sweden)

    Strąkowska Maria

    2016-09-01

    Full Text Available Measurement of the perfusion coefficient and thermal parameters of skin tissue using dynamic thermography is presented in this paper. A novel approach based on cold provocation and thermal modelling of skin tissue is presented. The measurement was performed on a person’s forearm using a special cooling device equipped with the Peltier module. The proposed method first cools the skin, and then measures the changes of its temperature matching the measurement results with a heat transfer model to estimate the skin perfusion and other thermal parameters. In order to assess correctness of the proposed approach, the uncertainty analysis was performed.

  4. On Proper Selection of Multihop Relays for Future Enhancement of AeroMACS Networks

    Science.gov (United States)

    Kamali, Behnam; Kerczewski, Robert J.; Apaza, Rafael D.

    2015-01-01

    As the Aeronautical Mobile Airport Communications System (AeroMACS) has evolved from a technology concept to a deployed communications network over major US airports, it is now time to contemplate whether the existing capacity of AeroMACS is sufficient to meet the demands set forth by all fixed and mobile applications over the airport surface given the AeroMACS constraints regarding bandwidth and transmit power. The underlying idea in this article is to present IEEE 802.16j-based WiMAX as a technology that can address future capacity enhancements and therefore is most feasible for AeroMACS applications. The principal argument in favor IEEE 802.16j technology is the flexible and cost effective extension of radio coverage that is afforded by relay fortified networks, with virtually no increase in the power requirements and virtually no rise in interference levels to co-allocated applications. The IEEE 802.16j-based multihop relay systems are briefly described. The focus is on key features of this technology, frame structure, and its architecture. Next, AeroMACS is described as a WiMAX-based wireless network. The two major relay modes supported by IEEE 802.16j amendment, i.e., transparent and non-transparent are described. The benefits of employing multihop relays are listed. Some key challenges related to incorporating relays into AeroMACS networks are discussed. The selection of relay type in a broadband wireless network affects a number of network parameters such as latency, signal overhead, PHY (Scalable Physical Layer) and MAC (Media Access Layer) layer protocols, consequently it can alter key network quantities of throughput and QoS (Quality of Service).

  5. Effect of gasification parameter on coal gasification in thermal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Shen, S.; Pang, X.; Bao, W.; Lo, Y.; Zhu, S. [Taiyuan University of Technology, Taiyuan (China)

    2004-12-01

    The influence of several parameters such as the power input of plasma jet, vapor and air input etc on gas composition and carbon conversion from coal gasification in an air-steam plasma jet was studied. The main gaseous products are H{sub 2}, CO, CO{sub 2}, CH{sub 2}4 and tar was discovered. Results show that the concentration of H{sub 2}, CO and carbon conversion increases, and the concentration of CO{sub 2} significantly decreases, when the power input of plasma jet is raised. The concentration of H{sub 2} increases when the vapor flux is increased, but excessive steam can decrease carbon conversion. The carbon conversion is enhanced by decreasing feed rate. The air flux should be reduced to improve the quality of coal gas in a certain range. The carbon conversion of Datong coal can exceed 95% at appropriate condition. 18 refs., 4 figs., 2 tabs.

  6. Active control and parameter updating techniques for nonlinear thermal network models

    Science.gov (United States)

    Papalexandris, M. V.; Milman, M. H.

    The present article reports on active control and parameter updating techniques for thermal models based on the network approach. Emphasis is placed on applications where radiation plays a dominant role. Examples of such applications are the thermal design and modeling of spacecrafts and space-based science instruments. Active thermal control of a system aims to approximate a desired temperature distribution or to minimize a suitably defined temperature-dependent functional. Similarly, parameter updating aims to update the values of certain parameters of the thermal model so that the output approximates a distribution obtained through direct measurements. Both problems are formulated as nonlinear, least-square optimization problems. The proposed strategies for their solution are explained in detail and their efficiency is demonstrated through numerical tests. Finally, certain theoretical results pertaining to the characterization of solutions of the problems of interest are also presented.

  7. Life Prediction of Atmospheric Plasma-Sprayed Thermal Barrier Coatings Using Temperature-Dependent Model Parameters

    Science.gov (United States)

    Zhang, B.; Chen, Kuiying; Baddour, N.; Patnaik, P. C.

    2017-06-01

    The failure analysis and life prediction of atmospheric plasma-sprayed thermal barrier coatings (APS-TBCs) were carried out for a thermal cyclic process. A residual stress model for the top coat of APS-TBC was proposed and then applied to life prediction. This residual stress model shows an inversion characteristic versus thickness of thermally grown oxide. The capability of the life model was demonstrated using temperature-dependent model parameters. Using existing life data, a comparison of fitting approaches of life model parameters was performed. A larger discrepancy was found for the life predicted using linearized fitting parameters versus temperature compared to those using non-linear fitting parameters. A method for integrating the residual stress was proposed by using the critical time of stress inversion. The role of the residual stresses distributed at each individual coating layer was explored and their interplay on the coating's delamination was analyzed.

  8. Simultaneous measurement of aero-optical distortion and turbulent structure in a heated boundary layer

    Science.gov (United States)

    Saxton-Fox, Theresa; McKeon, Beverley; Smith, Adam; Gordeyev, Stanislav

    2014-11-01

    This study examines the relationship between turbulent structures and the aero-optical distortion of a laser beam passing through a turbulent boundary layer. Previous studies by Smith et al. (AIAA, 2014--2491) have found a bulk convection velocity of 0 . 8U∞ for aero-optical distortion in turbulent boundary layers, motivating a comparison of the distortion with the outer boundary layer. In this study, a turbulent boundary layer is developed over a flat plate with a moderately-heated section of length 25 δ . Density variation in the thermal boundary layer leads to aero-optical distortion, which is measured with a Malley probe (Smith et al., AIAA, 2013--3133). Simultaneously, 2D PIV measurements are recorded in a wall-normal, streamwise plane centered on the Malley probe location. Experiments are run at Reθ = 2100 and at a Mach number of 0.03, with the heated wall 10 to 20°C above the free stream temperature. Correlations and conditional averages are carried out between Malley probe distortion angles and flow features in the PIV vector fields. Aero-optical distortion in this study will be compared to distortion in higher Mach number flows studied by Gordeyev et al. (J. Fluid Mech., 2014), with the aim of extending conclusions into compressible flows. This research is made possible by the Department of Defense through the National Defense & Engineering Graduate Fellowship (NDSEG) Program and by the Air Force Office of Scientific Research Grant # FA9550-12-1-0060.

  9. Mechanism and Kinetic Parameters of Thermal Decomposition of Cobalt Dichloride Hexahydrate

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The thermal decomposition of the cobalt dichloride hexahydrate and its kinetics were studied by TG and DTG technique under the non-isothermal condition with nitrogen atnosphere.The non-isothermal kinetic data and kinetic parameters were evaluated by means of integral and differential methods.The most probable mechanism functions of the thermal decomposition reaction for the first stage are:f(α)=(1-α)2 and g(α)=(1-α)-1-1.

  10. Determination of heterogeneous thermal parameters using ultrasound induced heating and MR thermal mapping.

    Science.gov (United States)

    Huttunen, Janne M J; Huttunen, Tomi; Malinen, Matti; Kaipio, Jari P

    2006-02-21

    In this paper, a method for the determination of spatially varying thermal conductivity and perfusion coefficients of tissue is proposed. The temperature evolution in tissue is modelled with the Pennes bioheat equation. The main motivation here is a model-based optimal control for ultrasound surgery, in which the tissue properties are needed when the treatment is planned. The overview of the method is as follows. The same ultrasound transducers, which are eventually used for the treatment, are used to inflict small temperature changes in tissue. This temperature evolution is monitored using MR thermal imaging, and the tissue properties are then estimated on the basis of these measurements. Furthermore, an approach to choose transducer excitations for the determination procedure is also considered. The purpose of this paper is to introduce a method and therefore simulations are used to verify the method. Furthermore, computations are accomplished in a 2D spatial domain.

  11. Thermal kinetic and dielectric parameters of acenaphthene crystal grown by vertical Bridgman technique

    Science.gov (United States)

    Karuppusamy, S.; Dinesh Babu, K.; Nirmal Kumar, V.; Gopalakrishnan, R.

    2016-05-01

    The bulk acenaphthene crystal was grown in a single-wall ampoule by vertical Bridgman technique. X-ray diffraction analysis confirmed the orthorhombic crystal system of title compound with space group Pcm21. Thermal behavior of compound was studied using thermogravimetry—differential scanning calorimetry analysis. Thermal kinetic parameters like activation energy, frequency factor, Avrami exponent, reaction rate and degree of conversion were calculated using Kissingers and Ozawa methods under non-isothermal condition for acenaphthene crystal and reported for the first time. The calculated thermal kinetic parameters are presented. Dielectric studies were performed to calculate the dielectric parameters such as dielectric constant, dielectric loss, AC conductivity, and activation energy from Arrhenius plot.

  12. Thermal expansion of lattice parameter of (powder) silicon up to 1473 K

    Institute of Scientific and Technical Information of China (English)

    XING Xianran; CHEN Jun; DENG Jinxia; LIU Guirong

    2004-01-01

    The XRPD (X-ray powder diffractometry) patterns of silicon powder with a unit cell structure of diamond were determined from 298 to 1473 K. Lattice parameters of Si linearly increase with temperature. The thermal shifts of the positions of all reflection peaks are linearly correlated with the temperature. The coefficients of the intrinsic linear thermal expansion and volumetric thermal expansion were determined as 3.87×10-6/K and 1.16 × 10-5/K respectively. It indicates that Si is still a suitable standard in the XRPD method at high temperatures.

  13. The DAN-AERO MW Experiments

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Bak, Christian; Schmidt Paulsen, Uwe

    This report describes the DAN-AERO MW experiments carried out within a collaborative, three years research project between Risø DTU and the industrial partners LM Glasfiber, Siemens Wind Power, Vestas Wind Systems A/S and the utility company DONG Energy. The main objective of the project was to e......This report describes the DAN-AERO MW experiments carried out within a collaborative, three years research project between Risø DTU and the industrial partners LM Glasfiber, Siemens Wind Power, Vestas Wind Systems A/S and the utility company DONG Energy. The main objective of the project...... in a wind tunnel and the unsteady 3D flow conditions on a rotor. The different transition characteristics might explain some of the differences between the 2D and 3D airfoil data and the experiments have been set up to provide data on this subject. The overall experimental approach has been to carry out...

  14. Lattice variation and thermal parameters of gel grown KDP crystals added with some ammonium compounds

    Indian Academy of Sciences (India)

    T H Freeda; C Mahadevan

    2001-10-01

    Pure and impurity added (with NH4Cl, NH4NO3, NH4H2PO4, and (NH4)2SO4) KDP single crystals were grown by the gel method using silica gels. X-ray diffraction data were collected for powder samples and used for the estimation of lattice variation and thermal parameters like Debye–Waller factor, mean-square amplitude of vibration, Debye temperature and Debye frequency. The thermal parameters do not vary in a particular order with respect to impurity concentration. The results obtained are reported and discussed.

  15. Finite element model for aero-elastically tailored residential wind turbine blade design

    Science.gov (United States)

    Robinson, Eric Alan

    Advances in passive wind turbine control systems have allowed wind turbines to achieve higher efficiencies and operate in wider inflow conditions than ever before. Within recent years, the adoption of aero-elastically tailored (bend-twist coupled) composite blades have been a pursued strategy. Unfortunately, for this strategy to be applied, traditional means of modeling, designing and manufacturing are no longer adequate. New parameters regarding non-linearities in deflections, stiffness, and aerodynamic loadings must now be implemented. To aid in the development of passive wind turbine system design, a finite element based aero-elastic program capable of computationally predicting blade deflection and twist under loading was constructed. The program was built around the idea of iteratively solving a blade composite structure to reach a maximum aero-elastic twist configuration under elevated wind speeds. Adopting a pre-existing blade geometry, from a pitch controlled small scale (3.5kW) turbine design, the program was tested to discover the geometry bend-twist coupling potential. This research would be a contributing factor in designing a passive pitch control replacement system for the turbine. A study of various model loading configurations was first performed to insure model validity. Then, a final model was used to analyze composite layups for selected spar configurations. Results characterize the aero-elastic twist properties for the selected configurations.

  16. Dependence of AeroMACS Interference on Airport Radiation Pattern Characteristics

    Science.gov (United States)

    Wilson, Jeffrey D.

    2012-01-01

    AeroMACS (Aeronautical Mobile Airport Communications System), which is based upon the IEEE 802.16e mobile wireless standard, is expected to be implemented in the 5091 to 5150 MHz frequency band. As this band is also occupied by Mobile Satellite Service (MSS) feeder uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference are under analysis in order to enable the definition of standards that assure that such interference will be avoided. In this study, the cumulative interference power distribution at low earth orbit from AeroMACS transmitters at the 497 major airports in the contiguous United States was simulated with the Visualyse Professional software. The dependence of the interference power on the number of antenna beams per airport, gain patterns, and beam direction orientations was simulated. As a function of these parameters, the simulation results are presented in terms of the limitations on transmitter power required to maintain the cumulative interference power under the established threshold.

  17. Studies on dynamic characteristics of the joint in the aero-engine rotor system

    Science.gov (United States)

    Shuguo, Liu; Yanhong, Ma; Dayi, Zhang; Jie, Hong

    2012-05-01

    The joint as a major part of the aero-engine rotating shafts directly influences its rotordynamics and state stability. This paper studies the dynamic effects of structure parameters and the external load on the stiffness and contact state of the rotor joints with nonlinear finite-element method and experiments. And a sensitivity analysis of critical speeds and vibration modes with respect to typical parameters (stiffness of the spline joints) is performed with finite difference methods, through two approaches, i.e. relative sensitivity analysis and absolute sensitivity analysis. The study results show that the stiffness and contact state of joints vary with external loads and geometry structures, and affect the rotor system operating. It is advisable to consider the influence of the position, structural parameter and external load of the rotor joints on aero-engine structure dynamics design.

  18. AeroValve Experimental Test Data Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Noakes, Mark W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-09-01

    This report documents the collection of experimental test data and presents performance characteristics for the AeroValve brand prototype pneumatic bidirectional solenoid valves tested at the Oak Ridge National Laboratory (ORNL) in July/August 2014 as part of a validation of AeroValve energy efficiency claims. The test stand and control programs were provided by AeroValve. All raw data and processing are included in the report attachments.

  19. Nanoscale size dependence parameters on lattice thermal conductivity of Wurtzite GaN nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Mamand, S.M., E-mail: soran.mamand@univsul.net [Department of Physics, College of Science, University of Sulaimani, Sulaimanyah, Iraqi Kurdistan (Iraq); Omar, M.S. [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq); Muhammad, A.J. [Department of Physics, College of Science, University of Kirkuk, Kirkuk (Iraq)

    2012-05-15

    Graphical abstract: Temperature dependence of calculated lattice thermal conductivity of Wurtzite GaN nanowires. Highlights: Black-Right-Pointing-Pointer A modified Callaway model is used to calculate lattice thermal conductivity of Wurtzite GaN nanowires. Black-Right-Pointing-Pointer A direct method is used to calculate phonon group velocity for these nanowires. Black-Right-Pointing-Pointer 3-Gruneisen parameter, surface roughness, and dislocations are successfully investigated. Black-Right-Pointing-Pointer Dislocation densities are decreases with the decrease of wires diameter. -- Abstract: A detailed calculation of lattice thermal conductivity of freestanding Wurtzite GaN nanowires with diameter ranging from 97 to 160 nm in the temperature range 2-300 K, was performed using a modified Callaway model. Both longitudinal and transverse modes are taken into account explicitly in the model. A method is used to calculate the Debye and phonon group velocities for different nanowire diameters from their related melting points. Effect of Gruneisen parameter, surface roughness, and dislocations as structure dependent parameters are successfully used to correlate the calculated values of lattice thermal conductivity to that of the experimentally measured curves. It was observed that Gruneisen parameter will decrease with decreasing nanowire diameters. Scattering of phonons is assumed to be by nanowire boundaries, imperfections, dislocations, electrons, and other phonons via both normal and Umklapp processes. Phonon confinement and size effects as well as the role of dislocation in limiting thermal conductivity are investigated. At high temperatures and for dislocation densities greater than 10{sup 14} m{sup -2} the lattice thermal conductivity would be limited by dislocation density, but for dislocation densities less than 10{sup 14} m{sup -2}, lattice thermal conductivity would be independent of that.

  20. Dynamical mechanism in aero-engine gas path system using minimum spanning tree and detrended cross-correlation analysis

    Science.gov (United States)

    Dong, Keqiang; Zhang, Hong; Gao, You

    2017-01-01

    Identifying the mutual interaction in aero-engine gas path system is a crucial problem that facilitates the understanding of emerging structures in complex system. By employing the multiscale multifractal detrended cross-correlation analysis method to aero-engine gas path system, the cross-correlation characteristics between gas path system parameters are established. Further, we apply multiscale multifractal detrended cross-correlation distance matrix and minimum spanning tree to investigate the mutual interactions of gas path variables. The results can infer that the low-spool rotor speed (N1) and engine pressure ratio (EPR) are main gas path parameters. The application of proposed method contributes to promote our understanding of the internal mechanisms and structures of aero-engine dynamics.

  1. Urban thermal environment and its biophysical parameters derived from satellite remote sensing imagery

    Science.gov (United States)

    Zoran, Maria A.; Savastru, Roxana S.; Savastru, Dan M.; Tautan, Marina N.; Baschir, Laurentiu V.

    2013-10-01

    In frame of global warming, the field of urbanization and urban thermal environment are important issues among scientists all over the world. This paper investigated the influences of urbanization on urban thermal environment as well as the relationships of thermal characteristics to other biophysical variables in Bucharest metropolitan area of Romania based on satellite remote sensing imagery Landsat TM/ETM+, time series MODIS Terra/Aqua data and IKONOS acquired during 1990 - 2012 period. Vegetation abundances and percent impervious surfaces were derived by means of linear spectral mixture model, and a method for effectively enhancing impervious surface has been developed to accurately examine the urban growth. The land surface temperature (Ts), a key parameter for urban thermal characteristics analysis, was also retrieved from thermal infrared band of Landsat TM/ETM+, from MODIS Terra/Aqua datasets. Based on these parameters, the urban growth, urban heat island effect (UHI) and the relationships of Ts to other biophysical parameters have been analyzed. Results indicated that the metropolitan area ratio of impervious surface in Bucharest increased significantly during two decades investigated period, the intensity of urban heat island and heat wave events being most significant. The correlation analyses revealed that, at the pixel-scale, Ts possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional scale, respectively. This analysis provided an integrated research scheme and the findings can be very useful for urban ecosystem modeling.

  2. Theoretical analysis for the specific heat and thermal parameters of solid C60

    Science.gov (United States)

    Soto, J. R.; Calles, A.; Castro, J. J.

    1997-08-01

    We present the results of a theoretical analysis for the thermal parameters and phonon contribution to the specific heat in solid C60. The phonon contribution to the specific heat is calculated through the solution of the corresponding dynamical matrix, for different points in the Brillouin zone, and the construccion of the partial and generalized phonon density of states. The force constants are obtained from a first principle calculation, using a SCF Hartree-Fock wave function from the Gaussian 92 program. The thermal parameters reported are the effective temperatures and vibrational amplitudes as a function of temperature. Using this model we present a parametization scheme in order to reproduce the general behaviour of the experimental specific heat for these materials.

  3. Thermal Hydraulic design parameters study for severe accidents using neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Chang Hyun; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Chang, Keun Sun [Sunmoon University, Asan (Korea, Republic of)

    1997-12-31

    To provide the information on severe accident progression is very important for advanced or new type of nuclear power plant (NPP) design. A parametric study, therefore, was performed to investigate the effect of thermal hydraulic design parameters on severe accident progression of pressurized water reactors (PWRs). Nine parameters, which are considered important in NPP design or severe accident progression, were selected among the various thermal hydraulic design parameters. The backpropagation neural network (BPN) was used to determine parameters, which might more strongly affect the severe accident progression, among nine parameters. For training, different input patterns were generated by the latin hypercube sampling (LHS) technique and then different target patterns that contain core uncovery time and vessel failure time were obtained for Young Gwang Nuclear (YGN) Units 3 and 4 using modular accident analysis program (MAAP) 3.0B code. Three different severe accident scenarios, such as two loss of coolant accidents (LOCAs) and station blackout (SBO), were considered in this analysis. Results indicated that design parameters related to refueling water storage tank (RWST), accumulator and steam generator (S/G) have more dominant effects on the progression of severe accidents investigated, compared to the other six parameters. 9 refs., 5 tabs. (Author)

  4. Evaluation of thermal-hydraulic parameter uncertainties in a TRIGA research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mesquita, Amir Z.; Costa, Antonio C.L.; Ladeira, Luiz C.D.; Rezende, Hugo C., E-mail: amir@cdtn.br, E-mail: aclc@cdtn.br, E-mail: lcdl@cdtn.br, E-mail: hcr@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Palma, Daniel A.P., E-mail: dapalma@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Experimental studies had been performed in the TRIGA Research Nuclear Reactor of CDTN/CNEN to find out the its thermal hydraulic parameters. Fuel to coolant heat transfer patterns must be evaluated as function of the reactor power in order to assess the thermal hydraulic performance of the core. The heat generated by nuclear fission in the reactor core is transferred from fuel elements to the cooling system through the fuel-cladding (gap) and the cladding to coolant interfaces. As the reactor core power increases the heat transfer regime from the fuel cladding to the coolant changes from single-phase natural convection to subcooled nucleate boiling. This paper presents the uncertainty analysis in the results of the thermal hydraulics experiments performed. The methodology used to evaluate the propagation of uncertainty in the results was done based on the pioneering article of Kline and McClintock, with the propagation of uncertainties based on the specification of uncertainties in various primary measurements. The uncertainty analysis on thermal hydraulics parameters of the CDTN TRIGA fuel element is determined, basically, by the uncertainty of the reactor's thermal power. (author)

  5. The Effect of Thermal Stress on Asphalt Workers’ Function and Their Physiological Parameters

    OpenAIRE

    RAMAZAN MIRZAEI; ROOHALAH HAJIZADEH; KEYKAOUS AZRAH; MOHAMMADHOSEIN BEHESHTI

    2015-01-01

    Heat stress effects on physical and mental health of workers and decreases human function. Asphalt workers are both exposed to the heat of their working process and to the sun heat. This study aimed at evaluating thermal stress and its following function fall and the effect of asphalt work on the degree of heat stress and asphalt workers’ physiological parameters. The present study was done at the work location of 29 asphalt workers in Qum City,  central  Iran.  The  degree  of  thermal stres...

  6. Aero-acoustic modeling using large eddy simulation

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Sørensen, Jens Nørkær

    2007-01-01

    The splitting technique for aero-acoustic computations is extended to simulate three-dimensional flow and acoustic waves from airfoils. The aero-acoustic model is coupled to a sub-grid-scale turbulence model for Large-Eddy Simulations. In the first test case, the model is applied to compute laminar...

  7. Influence of Feedstock Materials and Spray Parameters on Thermal Conductivity of Wire-Arc-Sprayed Coatings

    Science.gov (United States)

    Yao, H. H.; Zhou, Z.; Wang, G. H.; He, D. Y.; Bobzin, K.; Zhao, L.; Öte, M.; Königstein, T.

    2017-03-01

    To manufacture a protective coating with high thermal conductivity on drying cylinders in paper production machines, a FeCrB-cored wire was developed, and the spraying parameters for wire-arc spraying were optimized in this study. The conventional engineering materials FeCrAl and FeCrMo coatings were produced as the reference coatings under the same experimental condition. It has been shown that the oxide content in coating influences the thermal conductivity of coating significantly. The FeCrB coating exhibits a relative higher thermal conductivity due to the lower oxide content in comparison with conventional FeCrAl and FeCrMo coatings. Moreover, the oxidation of in-flight particles can be reduced by decreasing the standoff distance contributing to the increase in the thermal conductivity of coating. Total energy consumption of a papermaking machine can be significantly reduced if the coatings applied to dryer section exhibit high thermal conductivity. Therefore, the FeCrB coating developed in this study is a highly promising coating system for drying cylinders regarding the improved thermal conductivity and low operation costs in paper production industry.

  8. Influence of Feedstock Materials and Spray Parameters on Thermal Conductivity of Wire-Arc-Sprayed Coatings

    Science.gov (United States)

    Yao, H. H.; Zhou, Z.; Wang, G. H.; He, D. Y.; Bobzin, K.; Zhao, L.; Öte, M.; Königstein, T.

    2017-02-01

    To manufacture a protective coating with high thermal conductivity on drying cylinders in paper production machines, a FeCrB-cored wire was developed, and the spraying parameters for wire-arc spraying were optimized in this study. The conventional engineering materials FeCrAl and FeCrMo coatings were produced as the reference coatings under the same experimental condition. It has been shown that the oxide content in coating influences the thermal conductivity of coating significantly. The FeCrB coating exhibits a relative higher thermal conductivity due to the lower oxide content in comparison with conventional FeCrAl and FeCrMo coatings. Moreover, the oxidation of in-flight particles can be reduced by decreasing the standoff distance contributing to the increase in the thermal conductivity of coating. Total energy consumption of a papermaking machine can be significantly reduced if the coatings applied to dryer section exhibit high thermal conductivity. Therefore, the FeCrB coating developed in this study is a highly promising coating system for drying cylinders regarding the improved thermal conductivity and low operation costs in paper production industry.

  9. National aero-space plane: Flight mechanics

    Science.gov (United States)

    Mciver, Duncan E.; Morrell, Frederick R.

    1990-01-01

    The current status and plans of the U.S. National Aero-Space Plane (NASP) program are reviewed. The goal of the program is to develop technology for single stage, hypersonic vehicles which use airbreathing propulsion to fly directly to orbit. The program features an X-30 flight research vehicle to explore altitude-speed regimes not amenable to ground testing. The decision to build the X-30 is now scheduled for 1993, with the first flight in the late 1990's. The flight mechanics, controls, flight management, and flight test considerations for the X-30 are discussed.

  10. AERO-BACTERIOLOGICAL STUDY OF VEGETABLES MARKET AT JABALPUR

    Directory of Open Access Journals (Sweden)

    A. K. Pathak ، K. S. Verma

    2009-07-01

    Full Text Available Urban and rural vegetable markets of India characterized by mass activity with a little sanitary measure are responsible for generation of higher quantity of aerosols containing biotic and abiotic components. The aerosols generated in due course of mechanical disturbance, contain many organic compounds enable to sensitize vital respiratory organs of local inhabitants. Inhalation of airborne microorganisms can expose workers to risks from infection, toxicosis and allergy. The presence of non-spore forming gram-negative bacteria in air due to the mechanical areosolization indicates higher rate of dissemination of pollutants in these occupation associated areas. The present aero-bacteriological investigation included enumeration, identification and numerical analysis of different types of culturable airborne bacteria with inhalable fraction of gram-negative bacteria in the vegetable market of the city of Jabalpur, in order to measure the degree of aerobiopollution for this environment. The aero-bacteriological sampling has been done fortnightly for a period of one year. Samples were cultured based on standard methods. The survey revealed that in this type of atmosphere, environmental factors were responsible for the persistence of airborne bacteria with variable effects. The major contributors for aerosol generation were other mechanical activities, since this site is classified under human activity-enriched and highly trafficked site. The bioload of this atmosphere was recorded as high as 2.9 x 103 bacterial carrying particles per cubic meter during winter, dominated by both inhalable and non inhalable fractions of gram-negative bacteria. In summer, soil-borne bacteria were reported dominant in the air. High humidity and low temperature were the major factors for dissemination and distribution of gram-negative bacilli. A regression model with upto 43% variance was prepared in order to predict the bioload for this atmosphere in relation to

  11. Correlated parameter fit of arrhenius model for thermal denaturation of proteins and cells.

    Science.gov (United States)

    Qin, Zhenpeng; Balasubramanian, Saravana Kumar; Wolkers, Willem F; Pearce, John A; Bischof, John C

    2014-12-01

    Thermal denaturation of proteins is critical to cell injury, food science and other biomaterial processing. For example protein denaturation correlates strongly with cell death by heating, and is increasingly of interest in focal thermal therapies of cancer and other diseases at temperatures which often exceed 50 °C. The Arrhenius model is a simple yet widely used model for both protein denaturation and cell injury. To establish the utility of the Arrhenius model for protein denaturation at 50 °C and above its sensitivities to the kinetic parameters (activation energy E a and frequency factor A) were carefully examined. We propose a simplified correlated parameter fit to the Arrhenius model by treating E a, as an independent fitting parameter and allowing A to follow dependently. The utility of the correlated parameter fit is demonstrated on thermal denaturation of proteins and cells from the literature as a validation, and new experimental measurements in our lab using FTIR spectroscopy to demonstrate broad applicability of this method. Finally, we demonstrate that the end-temperature within which the denaturation is measured is important and changes the kinetics. Specifically, higher E a and A parameters were found at low end-temperature (50 °C) and reduce as end-temperatures increase to 70 °C. This trend is consistent with Arrhenius parameters for cell injury in the literature that are significantly higher for clonogenics (45-50 °C) vs. membrane dye assays (60-70 °C). Future opportunities to monitor cell injury by spectroscopic measurement of protein denaturation are discussed.

  12. X-Ray and Neutron Diffraction Studies on Thermal Parameters of Thalous Bromide

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Thermal parameters of TIBr were determined using both X-ray and neutron diffraction techniques. The data was analysed by Rietveld profile refinement procedure. From the neutron diffraction data, due to weak odd-order reflections, it was not possible to determine the individual thermal parameters. The X-ray diffraction measurements yielded BT1=0.296(5) nm2 and BBr=0.162(5) nm2. The overall isotropic value, B was 0.252(7) nm2 which is in good agreement with B=0.230(8) nm2 obtained from present neutron diffraction measurements. The present values are also in good agreement with theoretical estimates obtained from the shell models.

  13. Parameter estimation of breast tumour using dynamic neural network from thermal pattern

    Directory of Open Access Journals (Sweden)

    Elham Saniei

    2016-11-01

    Full Text Available This article presents a new approach for estimating the depth, size, and metabolic heat generation rate of a tumour. For this purpose, the surface temperature distribution of a breast thermal image and the dynamic neural network was used. The research consisted of two steps: forward and inverse. For the forward section, a finite element model was created. The Pennes bio-heat equation was solved to find surface and depth temperature distributions. Data from the analysis, then, were used to train the dynamic neural network model (DNN. Results from the DNN training/testing confirmed those of the finite element model. For the inverse section, the trained neural network was applied to estimate the depth temperature distribution (tumour position from the surface temperature profile, extracted from the thermal image. Finally, tumour parameters were obtained from the depth temperature distribution. Experimental findings (20 patients were promising in terms of the model’s potential for retrieving tumour parameters.

  14. Multi-parameter building thermal analysis using the lattice method for global optimisation

    Energy Technology Data Exchange (ETDEWEB)

    Saporito, A. [Fire and Environmental Modelling Centre, Building Research Establishment, Watford (United Kingdom); Day, A.R.; Karayiannis, T.G. [School of Engineering Systems and Design, South Bank University, London (United Kingdom); Parand, F. [Centre for Construction IT, Building Research Establishment, Watford (United Kingdom)

    2000-07-01

    The energy performance in buildings is a complex function of the building form and structure, heating system, occupancy pattern, operating schedules, and external climatic conditions. Computer simulations can help understand the dynamic interactions of these parameters. However, to carry out a multi-parameter analysis for the optimisation of the building energy performance, it is necessary to reduce the large number of tests resulting from all possible parameter combinations. In this paper, the lattice method for global optimisation (LMGO) for reducing the number of tests was used. A multi-parameter study was performed to investigate the heating energy use in office buildings using the thermal simulation code APACHE (IES-FACET). From the results of the sensitivity analysis it was possible to estimate the relative importance of various energy saving features. (author)

  15. Parameter sensitivity analysis of a simplified electrochemical and thermal model for Li-ion batteries aging

    Science.gov (United States)

    Edouard, C.; Petit, M.; Forgez, C.; Bernard, J.; Revel, R.

    2016-09-01

    In this work, a simplified electrochemical and thermal model that can predict both physicochemical and aging behavior of Li-ion batteries is studied. A sensitivity analysis of all its physical parameters is performed in order to find out their influence on the model output based on simulations under various conditions. The results gave hints on whether a parameter needs particular attention when measured or identified and on the conditions (e.g. temperature, discharge rate) under which it is the most sensitive. A specific simulation profile is designed for parameters involved in aging equations in order to determine their sensitivity. Finally, a step-wise method is followed to limit the influence of parameter values when identifying some of them, according to their relative sensitivity from the study. This sensitivity analysis and the subsequent step-wise identification method show very good results, such as a better fitting of the simulated cell voltage with experimental data.

  16. Performance Testing of Suspension Plasma Sprayed Thermal Barrier Coatings Produced with Varied Suspension Parameters

    Directory of Open Access Journals (Sweden)

    Nicholas Curry

    2015-07-01

    Full Text Available Suspension plasma spraying has become an emerging technology for the production of thermal barrier coatings for the gas turbine industry. Presently, though commercial systems for coating production are available, coatings remain in the development stage. Suitable suspension parameters for coating production remain an outstanding question and the influence of suspension properties on the final coatings is not well known. For this study, a number of suspensions were produced with varied solid loadings, powder size distributions and solvents. Suspensions were sprayed onto superalloy substrates coated with high velocity air fuel (HVAF -sprayed bond coats. Plasma spray parameters were selected to generate columnar structures based on previous experiments and were maintained at constant to discover the influence of the suspension behavior on coating microstructures. Testing of the produced thermal barrier coating (TBC systems has included thermal cyclic fatigue testing and thermal conductivity analysis. Pore size distribution has been characterized by mercury infiltration porosimetry. Results show a strong influence of suspension viscosity and surface tension on the microstructure of the produced coatings.

  17. Soil thermal resistivity and thermal stability measuring instrument. Volume 2: Manual for operation and use of the thermal property analyzer and statistical weather analysis program to determine thermal design parameters

    Science.gov (United States)

    Boggs, S. A.; Radhakrishna, H. S.; Chu, F. Y.; Ford, G. L.; Griffin, J. D. A.; Steinmanis, J.

    1981-11-01

    Numerous considerations influence the thermal design of an underground power cable, including the soil thermal resistivity, thermal diffusivity and thermal stability. Each of these properties is a function of soil moisture which is in turn a function of past weather, soil composition, and biological burden. The Neher-McGrath formalism has been widely used for thermal cable design. However, this formalism assumes knowledge of soil thermal properties (resistivity and diffusivity). For design purposes, these parameters should be treated statistically, since weather varies greatly from year to year. As well, soil thermal property surveys are normally required along the route to assess the thermal quality of the native soil. This project is intended to fill the gap between the need to carry out thermal design and the use of the Neher-McGrath formalism which is normally employed. This goal has been addressed through: development of instrumentation and methods of measuring soil thermal properties in situ and in the laboratory; recommendation of methods for conducting soil surveys along a proposed cable route and of assessing the thermal quality of soils; and development of a computerized method to treat soil thermal design parameters on a statistical basis using computerized weather records as supplied by the US Environmental Data Service. The use of the methods and instrumentation developed as a result of this contract should permit less conservative thermal design thereby improving the economics of underground transmission. As well, these techniques and instrumentation facilitate weather-dependent prediction of cable ampacity for installed cables, monitoring of backfill thermal stability, and many other new practices.

  18. Influence of micro-structural parameters and thermal cycling on the properties of CARDIFRC

    Indian Academy of Sciences (India)

    B L Karihaloo

    2012-02-01

    This paper gives an overview of the influence of micro-structural parameters on the mechanical properties of CARDIFRC which is a high-performance fibre-reinforced cement-based material. Since its development in 2002, several investigations have been made with a view to examine how its properties vary when its micro-structure is altered and when it is subjected to thermal cycling.

  19. Aero and vibroacoustics of automotive turbochargers

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen-Schaefer, Hung [Bosch Mahle Turbo Systems GmbH, Stuttgart (Germany)

    2013-02-01

    First book about the aeroacoustics of automotive turbochargers. Author of the book ''Rotordynamics of Automotive Turbochargers'', Springer, 2012. Written by an R and D expert in the turbocharger industry. Aero and Vibroacoustics of Automotive Turbochargers is a topic involving aspects from the working fields of thermodynamics of turbomachinery, aerodynamics, rotordynamics, and noise propagation computation. In this broadly interdisciplinary subject, thermodynamics of turbomachinery is used to design the turbocharger and to determine its operating conditions. Aerodynamics is needed to study the compressor flow dynamics and flow instabilities of rotating stall and surge, which can produce growling and whining-type noises. Rotordynamics is necessary to study rotor unbalance and self-excited oil-whirl instabilities, which lead to whistling and constant tone-type noises in rotating floating oil-film type bearings. For the special case of turbochargers using ball bearings, some high-order harmonic and wear noises also manifest in the rotor operating range. Lastly, noise propagation computation, based on Lighthill's analogy, is required to investigate airborne noises produced by turbochargers in passenger vehicles. The content of this book is intended for advanced undergraduates, graduates in mechanical engineering, research scientists and practicing engineers who want to better understand the interactions between these working fields and the resulting impact on the interesting topic of Aero and Vibroacoustics of Automotive Turbochargers.

  20. The structure and thermal parameters of ordered Cu65Fe10Pd25 ternary alloy

    Science.gov (United States)

    Ahmad, N.; Ziya, A. B.; Ibrahim, A.; Atiq, S.; Ahmad, S.; Bashir, F.

    2015-03-01

    Structural and thermal parameters have been studied in Cu65Fe10Pd25 alloy during order-disorder (O-D) transformation using differential scanning calorimetry (DSC) and high temperature X-ray diffraction (HTXRD). The results reveal that the Cu65Fe10Pd25 alloy undergoes an O-D transformation at Tc=797 K. The alloy shows L12 type ordering below Tc and has disordered face centered cubic (fcc) structure above Tc. The lattice parameter shows a positive deviation from Vegard's rule which may be related to the weakening of interatomic forces by the addition of Fe. The integrated intensity data obtained from the diffraction experiments was utilized to determine the coefficient of thermal expansion (α(T)), mean square amplitude of vibration (u2 bar (T)) and Debye temperatures (ΘD) during the O-D transformation. The abrupt change in the value of lattice parameter and coefficient of thermal expansion at Tc shows that the nature of O-D transition is first order. These results have been discussed by comparing them to those for Cu3Pd alloy.

  1. A ductile fracture criterion with Zener-Hollomon parameter of pure molybdenum sheet in thermal forming

    Directory of Open Access Journals (Sweden)

    Wang Chu

    2015-01-01

    Full Text Available Formability of pure molybdenum in thermal forming process has been greatly improved, but it is still hard to avoid the generation of rupture and other quality defects. In this paper, a ductile fracture criterion of pure molybdenum sheet in thermal forming was established by considering the plastic deformation capacity of material and stress states, which can be used to describe fracture behaviour and critical rupture prediction of pure molybdenum sheet during hot forming process. Based on the isothermal uniaxial tensile tests which performed at 993 to 1143 K with strain rate range from 0.0005 to 0.2 s−1, the material parameters are calculated by the combination method of experiment with FEsimulation. Based on the observation, new fracture criteria can be expressed as a function of Zener-Hollomon parameter. The critical fracture value that calculated by Oyane-Sato criterion increases with increasing temperature and decreasing strain rate. The ductile fracture criterion with Zener-Hollomon parameter of pure molybdenum in thermal forming is proposed.

  2. Evaluation of Silicon Neutron Resonance Parameters in the Energy Range Thermal to 1800 keV

    Energy Technology Data Exchange (ETDEWEB)

    Derrien, H.

    2002-09-30

    The evaluation of the neutron cross sections of the three stable isotopes of silicon in the energy range thermal to 20 MeV was performed by Hetrick et al. for ENDF/B-VI (Evaluated Nuclear Data File). Resonance parameters were obtained in the energy range thermal to 1500 keV from a SAMMY analysis of the Oak Ridge National Laboratory experimental neutron transmission data. A new measurement of the capture cross section of natural silicon in the energy range 1 to 700 keV has recently been performed at the Oak Ridge Electron Linear Accelerator. Results of this measurement were used in a SAMMY reevaluation of the resonance parameters, allowing determination of the capture width of a large number of resonances. The experimental data base is described; properties of the resonance parameters are given. For the first time the direct neutron capture component has been taken into account from the calculation by Rauscher et al. in the energy range from thermal to 1 MeV. Results of benchmark calculations are also given. The new evaluation is available in the ENDF/B-VI format.

  3. Sensitivity analysis of hydraulic and thermal parameters inducing anomalous heat flow in the Lower Yarmouk Gorge

    Science.gov (United States)

    Goretzki, Nora; Inbar, Nimrod; Kühn, Michael; Möller, Peter; Rosenthal, Eliyahu; Schneider, Michael; Siebert, Christian; Magri, Fabien

    2016-04-01

    The Lower Yarmouk Gorge, at the border between Israel and Jordan, is characterized by an anomalous temperature gradient of 46 °C/km. Numerical simulations of thermally-driven flow show that ascending thermal waters are the result of mixed convection, i.e. the interaction between the regional flow from the surrounding heights and buoyant flow within permeable faults [1]. Those models were calibrated against available temperature logs by running several forward problems (FP), with a classic "trial and error" method. In the present study, inverse problems (IP) are applied to find alternative parameter distributions that also lead to the observed thermal anomalies. The investigated physical parameters are hydraulic conductivity and thermal conductivity. To solve the IP, the PEST® code [2] is applied via the graphical interface FEPEST® in FEFLOW® [3]. The results show that both hydraulic and thermal conductivity are consistent with the values determined with the trial and error calibrations, which precede this study. However, the IP indicates that the hydraulic conductivity of the Senonian Paleocene aquitard can be 8.54*10-3 m/d, which is three times lower than the originally estimated value in [1]. Moreover, the IP suggests that the hydraulic conductivity in the faults can increase locally up to 0.17 m/d. These highly permeable areas can be interpreted as local damage zones at the faults/units intersections. They can act as lateral pathways in the deep aquifers that allow deep outflow of thermal water. This presentation provides an example about the application of FP and IP to infer a wide range of parameter values that reproduce observed environmental issues. [1] Magri F, Inbar N, Siebert C, Rosenthal E, Guttman J, Möller P (2015) Transient simulations of large-scale hydrogeological processes causing temperature and salinity anomalies in the Tiberias Basin. Journal of Hydrology, 520, 342-355 [2] Doherty J (2010) PEST: Model-Independent Parameter Estimation. user

  4. Effects of operation temperature on thermal expansion and main parameters of radial ball bearings

    Directory of Open Access Journals (Sweden)

    Mitrović Radivoje M.

    2015-01-01

    Full Text Available The research of influence of operation temperature on the thermal expansion and main parameters of radial ball bearings is presented in this paper. The main bearing parameters are identified in accordance with the increasing requests concerning stability and load capacity. A series of Finite Element Analyses is performed for quasi-static analysis of all identified bearing parameters during contact period in referent temperature. Then, the dependence of bearing material characteristics on the operation temperature is discussed. Few series of Finite Element Analyses are performed for a particular radial ball bearing type, with characteristics in accordance with manufacturer specifications, for several operation temperatures. These two problems analyses include consideration of relation between the initial radial clearance, thermal expansion strains and contact deformations of the parts of the bearing assembly. The results for radial ball bearing parameters are monitored during a ball contact period for different temperatures and the appropriate discussion and conclusions are given. The conclusions about the contribution of developed procedure in defining the optimum operation temperature range are shown. [Projekat Ministarstva nauke Republike Srbije, br. TR 35029 i br. OI 174001

  5. Blackness coefficients, effective diffusion parameters, and control rod worths for thermal reactors - methods

    Energy Technology Data Exchange (ETDEWEB)

    Bretscher, M.M.

    1984-01-01

    Simple diffusion theory cannot be used to evaluate control rod worths in thermal neutron reactors because of the strongly absorbing character of the control material. However, reliable control rod worths can be obtained within the framework of diffusion theory if the control material is characterized by a set of mesh-dependent effective diffusion parameters. For thin slab absorbers the effective diffusion parameters can be expressed as functions of a suitably-defined pair of blackness coefficients. Methods for calculating these blackness coefficients in the P/sub 1/, P/sub 3/, and P/sub 5/ approximations, with and without scattering, are presented. For control elements whose geometry does not permit a thin slab treatment, other methods are needed for determining the effective diffusion parameters. One such method, based on reaction rate ratios, is discussed.

  6. External Thermal Insulation Composite Systems: Critical Parameters for Surface Hygrothermal Behaviour

    Directory of Open Access Journals (Sweden)

    Eva Barreira

    2014-01-01

    Full Text Available External Thermal Insulation Composite Systems (ETICS are often used in Europe. Despite its thermal advantages, low cost, and ease of application, this system has serious problems of biological growth causing the cladding defacement. Recent studies pointed that biological growth is due to high values of surface moisture content, which mostly results from the combined effect of exterior surface condensation, wind-driven rain, and drying process. Based on numerical simulation, this paper points the most critical parameters involved in hygrothermal behaviour of ETICS, considering the influence of thermal and hygric properties of the external rendering, the effect of the characteristics of the façade, and the consequences of the exterior and interior climate on exterior surface condensation, wind-driven rain, and drying process. The model used was previously validated by comparison with the results of an “in situ” campaign. The results of the sensitivity analyses show that relative humidity and temperature of the exterior air, atmospheric radiation, and emissivity of the exterior rendering are the parameters that most influence exterior surface condensation. Wind-driven rain depends mostly on horizontal rain, building’s height, wind velocity, and orientation. The drying capacity is influenced by short-wave absorbance, incident solar radiation, and orientation.

  7. Thermal manipulation during embryogenesis improves certain semen parameters in layer breeder chicken during hot climatic conditions.

    Science.gov (United States)

    Shanmugam, M; Vinoth, A; Rajaravindra, K S; Rajkumar, U

    2015-10-01

    Thermal manipulation during incubation has been shown to improve post hatch performance in poultry. The aim of the present experiment was to evaluate thermal manipulation on semen quality of roosters during hot climatic conditions. Eggs obtained after artificial insemination from Dahlem Red layer breeders were randomly divided into two groups control (C) and heat exposed (HE). C group eggs were incubated at 37.5°C throughout the incubation period while the HE group eggs were exposed to higher temperature 40.5°C from 15th to 17th day of incubation for 3h each day. The relative humidity was maintained at 65% in both the groups throughout incubation. The chicks hatched were reared separately under standard husbandry conditions. During high ambient temperature semen from roosters (45 weeks of age) was collected and evaluated for different gross parameters, sperm chromatin integrity and sperm HSP27 and HSP70 gene expression by real-time PCR. The seminal plasma was evaluated for lipid peroxidation, ferric ion reducing antioxidant power (FRAP), triiodothyronine (T3) and matrix metalloproteinase-2 (MMP-2) activity. The shed average Temperature Humidity Index (THI) during the experiment period was 78.55. The percent live sperm and FRAP level were significantly (Pcould be concluded that thermal manipulation during incubation improves certain semen parameters of roosters at high ambient temperature.

  8. Impact of indoor thermal comfort on physiological parameters of human body

    Institute of Scientific and Technical Information of China (English)

    郑洁; 张瑜; 姚润明

    2009-01-01

    With the living standards gradually improved,the buildings with safe,comfortable,healthy indoor thermal environment would be the ideal pursuit. But to create the preferable indoor thermal environment,it is necessary to research physiological influence of indoor thermal environment on human body. So a typical region of hot-humid climate in Chongqing,China,was considered as the object to study physiological indexes of human body. And the indoor thermal environment parameters and physiological indexes of human body were the main measurements. 20 volunteer students were organized to take part in the experiments in the laboratory during this summer. And two methods,physical measuring and questionnaire investigation,were used in the experiments. The results show that the increase in indoor air temperature reduces the uncomfortable feeling of air draft. Indoor air temperature has visible effects on MCS (motor nerve conduction speed),SCS (sensory nerve conduction speed),HR (heart rate),the ECG (electrocardiogram)-QT segment and SSEP (short somatosensory evoked potential)-latent period of N9. Therefore,a safe,comfortable and healthful indoor environment can be created by considering these factors.

  9. Aero and vibroacoustics of automotive turbochargers

    CERN Document Server

    Nguyen-Schäfer, Hung

    2013-01-01

    Aero and Vibroacoustics of Automotive Turbochargers is a topic involving aspects from the working fields of thermodynamics of turbomachinery, aerodynamics, rotordynamics, and noise propagation computation.   In this broadly interdisciplinary subject, thermodynamics of turbomachinery is used to design the turbocharger and to determine its operating conditions.  Aerodynamics is needed to study the compressor flow dynamics and flow instabilities of rotating stall and surge, which can produce growling and whining-type noises. Rotordynamics is necessary to study rotor unbalance and self-excited oil-whirl instabilities, which lead to whistling and constant tone-type noises in rotating floating oil-film type bearings. For the special case of turbochargers using ball bearings, some high-order harmonic and wear noises also manifest in the rotor operating range. Lastly, noise propagation computation, based on Lighthill’s analogy, is required to investigate airborne noises produced by turbochargers in passenger vehi...

  10. Thermal hydraulic simulations, error estimation and parameter sensitivity studies in Drekar::CFD

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Thomas Michael; Shadid, John N; Pawlowski, Roger P; Cyr, Eric C; Wildey, Timothy Michael

    2014-01-01

    This report describes work directed towards completion of the Thermal Hydraulics Methods (THM) CFD Level 3 Milestone THM.CFD.P7.05 for the Consortium for Advanced Simulation of Light Water Reactors (CASL) Nuclear Hub effort. The focus of this milestone was to demonstrate the thermal hydraulics and adjoint based error estimation and parameter sensitivity capabilities in the CFD code called Drekar::CFD. This milestone builds upon the capabilities demonstrated in three earlier milestones; THM.CFD.P4.02 [12], completed March, 31, 2012, THM.CFD.P5.01 [15] completed June 30, 2012 and THM.CFD.P5.01 [11] completed on October 31, 2012.

  11. Determination of dispersion parameters of thermally deposited CdTe thin film

    Science.gov (United States)

    Dhimmar, J. M.; Desai, H. N.; Modi, B. P.

    2016-05-01

    Cadmium Telluride (CdTe) thin film was deposited onto glass substrates under a vacuum of 5 × 10-6 torr by using thermal evaporation technique. The prepared film was characterized for dispersion analysis from reflectance spectra within the wavelength range of 300 nm - 1100 nm which was recorded by using UV-Visible spectrophotometer. The dispersion parameters (oscillator strength, oscillator wavelength, high frequency dielectric constant, long wavelength refractive index, lattice dielectric constant and plasma resonance frequency) of CdTe thin film were investigated using single sellimeir oscillator model.

  12. Effect of thermal history on Mossbauer signature and hyperfine interaction parameters of copper ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Modi, K. B., E-mail: kunalbmodi2003@yahoo.com; Raval, P. Y.; Dulera, S. V.; Kathad, C. R.; Shah, S. J.; Trivedi, U. N. [Department of Physics, Saurashtra University, Rajkot-360005 (India); Chandra, Usha [High pressure Physics Laboratory, Department of Physics, University of Rajasthan, Jaipur-302004 (India)

    2015-06-24

    Two specimens of copper ferrite, CuFe{sub 2}O{sub 4}, have been synthesized by double sintering ceramic technique with different thermal history i.e. slow cooled and quenched. X-ray diffractometry has confirmed single phase fcc spinel structure for slow cooled sample while tetragonal distortion is present in quenched sample. Mossbauer spectral analysis for slow-cooled copper ferrite reveals super position of two Zeeman split sextets along with paramagnetic singlet in the centre position corresponds to delafossite (CuFeO{sub 2}) phase that is completely absent in quenched sample. The hyperfine interaction parameters are highly influenced by heat treatment employed.

  13. Indoor thermal comfort studies based on physiological parameter measurement and questionnaire investigation

    Institute of Scientific and Technical Information of China (English)

    ZHENG Jie; CHEN Liang; LI Bai-zhan; CHEN Lu

    2006-01-01

    Physiological parameters of people and enact assessment standard of indoor thermal environment that are appropriate to our national conditions were explored from the perspective of physiology. From December 2005 to January 2006, nerve conduction velocities and skin temperatures of 20 healthy students were tested with questionnaire investigation. The results show that the nerve conduction velocities as well as skin temperatures present an obvious decline trend in a continuous draught, and that the nerve conduction velocities and skin temperatures have a definite linear relationship. Draught velocity is an important factor in winter that affects body comfort, and the subjects are sensitive to air velocity.

  14. Aeronautical Mobile Airport Communications System (AeroMACS)

    Science.gov (United States)

    Budinger, James M.; Hall, Edward

    2011-01-01

    To help increase the capacity and efficiency of the nation s airports, a secure wideband wireless communications system is proposed for use on the airport surface. This paper provides an overview of the research and development process for the Aeronautical Mobile Airport Communications System (AeroMACS). AeroMACS is based on a specific commercial profile of the Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard known as Wireless Worldwide Interoperability for Microwave Access or WiMAX (WiMax Forum). The paper includes background on the need for global interoperability in air/ground data communications, describes potential AeroMACS applications, addresses allocated frequency spectrum constraints, summarizes the international standardization process, and provides findings and recommendations from the world s first AeroMACS prototype implemented in Cleveland, Ohio, USA.

  15. MEMS and mil/aero: technology push and market pull

    Science.gov (United States)

    Clifford, Thomas H.

    2001-04-01

    MEMS offers attractive solutions to high-density fluidics, inertial, optical, switching and other demanding military/aerospace (mil/aero) challenges. However, full acceptance must confront the realities of production-scale producibility, verifiability, testability, survivability, as well as long-term reliability. Data on these `..ilities' are crucial, and are central in funding and deployment decisions. Similarly, mil/aero users must highlight specific missions, environmental exposures, and procurement issues, as well as the quirks of its designers. These issues are particularly challenging in MEMS, because of the laws of physics and business economics, as well as the risks of deploying leading-edge technology into no-fail applications. This paper highlights mil/aero requirements, and suggests reliability/qualification protocols, to guide development effort and to reassure mil/aero users that MEMS labs are mindful of the necessary realities.

  16. Recent trends in superalloys research for critical aero-engine components

    Energy Technology Data Exchange (ETDEWEB)

    Remy, Luc [Mine ParisTech, CNRS UMR 7633, 91 - Evry (France). Centre des Materiaux; Guedou, Jean-Yves [Snecma Safran Group, Moissy-Cramayel (France). Materials and Processes Dept.

    2010-07-01

    This paper is a brief survey of common research activity on superalloys for aero-engines between Snecma and Mines ParisTech Centre des Materiaux during recent years. First in disks applications, the development of new powder metallurgy superalloys is shown. Then grain boundary engineering is investigated in a wrought superalloy. Secondly, design oriented research on single crystals blades is shown: a damage model for low cycle fatigue is used for life prediction when cracks initiated at casting pores. The methodology developed for assessing coating life is illustrated for thermal barrier coating deposited on AMI single crystal superalloy. (orig.)

  17. Processing of thermal parameters for the assessment of geothermal potential of sedimentary basins

    Science.gov (United States)

    Pasquale, V.; Chiozzi, P.; Gola, G.; Verdoya, M.

    2009-04-01

    The growing interest on renewable energy sources is stimulating new efforts aimed at the assessment of geothermal potential in several countries, and new developments are expected in the near future. In this framework, a basic step forward is to focus geothermal investigations on geological environments which so far have been relatively neglected. Some intracontinental sedimentary basins could reveal important low enthalpy resources. The evaluation of the geothermal potential in such geological contexts involves the synergic use of geophysical and hydrogeological methodologies. In sedimentary basins a large amount of thermal and hydraulic data is generally available from petroleum wells. Unfortunately, borehole temperature data are often affected by a number of perturbations which make very difficult determination of the true geothermal gradient. In this paper we addressed the importance of the acquisition of thermal parameters (temperature, geothermal gradient, thermal properties of the rock) and the technical processing which is necessary to obtain reliable geothermal characterizations. In particular, techniques for corrections of bottom-hole temperature (BHT) data were reviewed. The objective was to create a working formula usable for computing the undisturbed formation temperature for specific sedimentary basins. As test areas, we analysed the sedimentary basins of northern Italy. Two classical techniques for processing temperature data from oil wells are customarily used: (i) the method by Horner, that requires two or more measurements of bottom-hole temperatures carried out at the same depth but at different shut-in times te and (ii) the technique by Cooper and Jones, in which several physical parameters of the mud and formation need to be known. We applied both methods to data from a number of petroleum explorative wells located in two areas of the Po Plain (Apenninic buried arc and South Piedmont Basin - Pedealpine homocline). From a set of about 40 wells

  18. MCNP5 study on kinetics parameters of coupled fast-thermal system HERBE

    Directory of Open Access Journals (Sweden)

    Pešić Milan P.

    2011-01-01

    Full Text Available New validation of the well-known Monte Carlo code MCNP5 against measured criticality and kinetics data for the coupled fast-thermal HERBE System at the Reactor B critical assembly is shown in this paper. Results of earlier calculations of these criticality and kinetics parameters, done by combination of transport and diffusion codes using two-dimension geometry model are compared to results of new calculations carried out by the MCNP5 code in three-dimension geometry. Satisfactory agreements in comparison of new results with experimental data, in spite complex heterogeneous composition of the HERBE core, are achieved confirming that MCNP5 code could apply successfully to study on HERBE kinetics parameters after uncertainties in impurities in material compositions and positions of fuel elements in fast zone were removed.

  19. Effects of nanoscale size dependent parameters on lattice thermal conductivity in Si nanowire

    Indian Academy of Sciences (India)

    M S Omar; H T Taha

    2010-04-01

    The effects of nanoscale size dependent parameters on lattice thermal conductivity are calculated using the Debye–Callaway model including transverse and longitudinal modes explicitly for Si nanowire with diameters of 115, 56, 37 and 22 nm. A direct method is used to calculate the group velocity for different size nanowire from their related calculated melting point. For all diameters considered, the effects of surface roughness, defects and transverse and longitudinal Gruneisen parameters are successfully used to correlate the calculated values of lattice thermal conductivity to that of the reported experimental curve. The obtained fitting value for mean Gruneisen parameter has a systematic dependence on all Si nanowire diameters changing from 0·791 for 115 nm diameter to 1·515 for the 22 nm nanowire diameter. The dependence also gave a suggested surface thickness of about 5–6 nm. The other two parameters were found to have partially systematic dependence for diameters 115, 56, and 37 nm for defects and 56, 37 and 22 nm for the roughness. When the diameters go down from 115 to 22 nm, the concentration of dislocation increased from 1·16 × 1019cm-3 to 5·20 × 1019cm-3 while the surface roughness found to increase from 0·475 to 0·130 and the rms height deviation from the surface changes by about 1·66 in this range of diameter. The diameter dependence also indicates a strong control of surface effect in surface to bulk ratio for the 22 nm wire diameter.

  20. Blood biochemical parameters of broilers fed differently thermal processed soybean meal

    Directory of Open Access Journals (Sweden)

    Mojgan Nahavandinejad

    2014-09-01

    Full Text Available Objective. A 42-days feeding trial was carried out to evaluate the influences of differently thermal processed soybean meal on the broilers blood biochemical parameters. Materials and methods. A total of 200 male birds of Ross strain were allocated into five different diets formulated using differently heat-treated soybean meals, with ten birds per treatment and per replicate. Diets contained: raw soybean (controls, autoclaved for a short (121°C, 20 min; Aut1 group or medium length period (121°C, 30 min; Aut2 group soybean meal, micro-waved soybean meal (46°C, 540 Watt, 7 min; McW group and browned soybean meal (120°C, 20 min; Brn group. Results. Blood serum metabolites showed that all treated diets presented lower lipid metabolism makers and higher protein metabolism markers. Broilers showed increased final body weight when fed heat-treated meals compared with control. Results suggested that thermal treatments altered the lipid metabolism in broilers that might originate a decrease in abdominal fat deposition. Conclusions. Comparison of the results for all the treated groups showed the Aut2 treatment is the most suitable method for soybean thermal treatment processing; in contrast, the Aut1 treatment had the closest results to the control group.

  1. Influences of fine pitch solder joint shape parameters on fatigue life under thermal cycle

    Institute of Scientific and Technical Information of China (English)

    HUANG Chun-yue; WU Zhao-hua; HUANG Hong-yan; ZHOU De-jian

    2005-01-01

    The solder joint reliability of a 0. 5 mm lead pitch, 240-pin quad flat package(QFP) was studied by nonlinear finite element analysis(FEA). The stress/strain distributions within the solder joints and the maximum plastic strain range of the solder joints were determined. Based on the calculated maximum plastic strain range the thermal fatigue life of the solder joints was calculated using Coffin-Manson equation. The influences of shape parameters including volume of solder joint, pad size and stand-off on the thermal fatigue life of the solder joints were also studied. The results show that the stress and strain distribution in the solder joint are not uniform; the interface between the lead and the solder joint is the high stress and strain region; the maximum stress and stain occur at the topmost point where the solder joint intersects with the inner side of the lead. The solder joint cracks should occur firstly at this point and propagate along the interface between the solder and the lead. The solder joint with the pad size of 1.25 mm× 0.35 mm, the stand-off of 0.02 mm and the solder volume of 0. 026 mm3 has longer fatigue life than that of any others. These optimal parameters have been applied in practice to assemble the 240-pin, 0.5 mm pitch QFP.

  2. Neutron-deuteron system and the photon polarization parameter at thermal neutron energies

    Science.gov (United States)

    Sadeghi, H.

    2007-04-01

    Effective field theory (EFT) is the unique, model independent and systematic low-energy version of QCD for processes involving momenta below the pion mass. A low-energy photonuclear observable in three-body systems, photon polarization parameter at thermal neutron energies is calculated by using pionless EFT up to next-to-next to leading order (NLO2). In order to make a comparative study of this model, we compared our results for photon polarization parameter with the realistic Argonne v18 two-nucleon and Urbana IX or Tucson-Melbourne three-nucleon interactions. Three-body currents give small but significant contributions to some of the observables in the neutron-deuteron radiative capture cross section at thermal neutron energies. In this formalism the three-nucleon forces are needed up to NLO2 for cut-off independent results. Our result converges order by order in low energy expansion and also cut-off independent at this order.

  3. Neutron-Deuteron System and Photon Polarization Parameter at Thermal Neutron Energies

    CERN Document Server

    Sadeghi, H

    2007-01-01

    Effective Field Theory(EFT) is, the unique, model independent and systematic low-energy version of QCD for processes involving momenta below the pion mass. A low-energy photo-nuclear observable in three-body systems, photon polarization parameter at thermal neutron energies is calculated by using pionless EFT up to next-to-next to leading order(N$^2$LO). In order to make a comparative study of this model, we compared our results for photon polarization parameter with the realistic Argonne $v_{18}$ two-nucleon and Urbana IX or Tucson-Melbourne three-nucleon interactions. Three-body currents give small but significant contributions to some of the observables in the neutron-deuteron radiative capture cross section at thermal neutron energies. In this formalism the three-nucleon forces are needed up to N$^2$LO for cut-off independent results. Our result converges order by order in low energy expansion and also cut-off independent at this order.

  4. Aero-optical effects of an optical seeker with a supersonic jet for hypersonic vehicles in near space.

    Science.gov (United States)

    Guo, Guangming; Liu, Hong; Zhang, Bin

    2016-06-10

    The aero-optical effects of an optical seeker with a supersonic jet for hypersonic vehicles in near space were investigated by three suites of cases, in which the altitude, angle of attack, and Mach number were varied in a large range. The direct simulation Monte Carlo based on the Boltzmann equation was used for flow computations and the ray-tracing method was used to simulate beam transmission through the nonuniform flow field over the optical window. Both imaging displacement and phase deviation were proposed as evaluation parameters, and along with Strehl ratio they were used to quantitatively evaluate aero-optical effects. The results show that aero-optical effects are quite weak when the altitude is greater than 30 km, the imaging displacement is related to the incident angle of a beam, and it is minimal when the incident angle is approximately 15°. For reducing the aero-optical effects, the optimal location of an aperture should be in the middle of the optical window.

  5. Genetic parameter estimation for juvenile growth and upper thermal tolerance in turbot (Scophthalmus maximus Linnaeus)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tianshi; KONG Jie; LIU Baosuo; WANG Qingyin; CAO Baoxiang; LUAN Sheng; WANG Weiji

    2014-01-01

    Twenty-six half-sib groups (53 full-sib families) of turbot,Scophthalmus maximus Linnaeus, were obtained by artificial insemination. We measured growth in the offspring (40-50 individuals/family) and subjected them to a thermal tolerance challenge over a period of 34 d. There was no significant difference in daily mor-tality (range: 0.580%-1.391%) between Days 1-13 during the thermal tolerance challenge. However, daily cumulative mortality increased rapidly between Days 14 and 29, especially on Days 15 and 16 (20.232% and 34.377%, respectively). Mortality was highest on Day 16 (14.145%). We estimated the genetic parameters using the average information restricted maximum likelihood method. We used a likelihood ratio test to evaluate the significance of effects in models with and without identity as an effect, and compared the final log-likelihoods (maximum log L). Lastly, we estimated phenotypic and genetic correlation between the up-per thermal tolerance limit (UTT) and body weight (BW). In this study, the positive phenotypic correlation was low between UTT and BW (0.093±0.029). The genetic correlation between UTT and BW was negative (-0.044±0.239). The heritability for upper thermal tolerance was low (0.087±0.032), which is of approximate-ly moderate heritability. The heritability for body weight was high (0.303±0.074). Our results suggest there is significant potential for improvement in the culture of turbot by selective breeding.

  6. Parameters measurement for the thermal neutron beam in the thermal column hole of Xi’an pulse reactor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The distribution of the neutron spectra in the thermal column hole of Xi’an pulse reactor was measured with the time-of-flight method.Compared with the thermal Maxwellian theory neutron spectra,the thermal neutron spectra measured is a little softer,and the average neutron energy of the experimental spectra is about 0.042±0.01 eV.The thermal neutron fluence rate at the front end of thermal column hole,measured with gold foil activation techniques,is about 1.18×105 cm-2 s-1.The standard uncertainty of the measured thermal neutron fluence is about 3%.The spectra-averaged cross section of 197Au(n,γ) determined by the experimental thermal neutron spectra is(92.8±0.93) ×10-24 cm2.

  7. Multidisciplinary Design Optimization on Conceptual Design of Aero-engine

    Science.gov (United States)

    Zhang, Xiao-bo; Wang, Zhan-xue; Zhou, Li; Liu, Zeng-wen

    2016-06-01

    In order to obtain better integrated performance of aero-engine during the conceptual design stage, multiple disciplines such as aerodynamics, structure, weight, and aircraft mission are required. Unfortunately, the couplings between these disciplines make it difficult to model or solve by conventional method. MDO (Multidisciplinary Design Optimization) methodology which can well deal with couplings of disciplines is considered to solve this coupled problem. Approximation method, optimization method, coordination method, and modeling method for MDO framework are deeply analyzed. For obtaining the more efficient MDO framework, an improved CSSO (Concurrent Subspace Optimization) strategy which is based on DOE (Design Of Experiment) and RSM (Response Surface Model) methods is proposed in this paper; and an improved DE (Differential Evolution) algorithm is recommended to solve the system-level and discipline-level optimization problems in MDO framework. The improved CSSO strategy and DE algorithm are evaluated by utilizing the numerical test problem. The result shows that the efficiency of improved methods proposed by this paper is significantly increased. The coupled problem of VCE (Variable Cycle Engine) conceptual design is solved by utilizing improved CSSO strategy, and the design parameter given by improved CSSO strategy is better than the original one. The integrated performance of VCE is significantly improved.

  8. Aero-sol-gel Reactor for Nano-powder Synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Beaucage, G.; Hyeon-Lee, J.; Kohls, D.J. [University of Cincinnati, Department of Materials Science and Engineering (United States); Pratsinis, S.E. [University of Cincinnati, Department of Chemical Engineering (United States)

    1999-09-15

    This paper discusses a new approach to the synthesis of nano-structured oxides where sol-gel reactions are carried out in aerosol droplets. This aero-sol-gel (ASG) reactor allows for manipulation of the structure, chemical composition and surface area of silica powders through variation of process parameters. ASG powders differ in nanostructure from other continuous process powders such as pyrolytic and solution-route powders. ASG powders contain mesopores (>2-nm) and micropores (<2-nm), the mesopores being responsible for high surface areas measured by nitrogen adsorption using BET theory. Primary particles of close to molecular scale are believed to lead to exceedingly large specific surface areas on the order of 600-m{sup 2}/g. These primary particles aggregate into nanometer scale mass-fractal aggregates that cluster in micron scale agglomerates. Under controlled reaction conditions the powder structure is reproducible as measured by small-angle X-ray scattering, SAXS, analysis. The ASG reactor displays transport effects similar to those previously seen in laminar flame reactors as evidenced by the effect of reactor geometry and reactant concentration on product structure.

  9. Aero-Assisted Spacecraft Missions Using Hypersonic Waverider Aeroshells

    Science.gov (United States)

    Knittel, Jeremy

    This work examines the use of high-lift, low drag vehicles which perform orbital transfers within a planet's atmosphere to reduce propulsive requirements. For the foreseeable future, spacecraft mission design will include the objective of limiting the mass of fuel required. One means of accomplishing this is using aerodynamics as a supplemental force, with what is termed an aero-assist maneuver. Further, the use of a lifting body enables a mission designer to explore candidate trajectory types wholly unavailable to non-lifting analogs. Examples include missions to outer planets by way of an aero-gravity assist, aero-assisted plane change, aero-capture, and steady atmospheric periapsis probing missions. Engineering level models are created in order to simulate both atmospheric and extra-atmospheric space flight. Each mission is parameterized using discrete variables which control multiple areas of design. This work combines the areas of hypersonic aerodynamics, re-entry aerothermodynamics, spacecraft orbital mechanics, and vehicle shape optimization. In particular, emphasis is given to the parametric design of vehicles known as "waveriders" which are inversely designed from known shock flowfields. An entirely novel means of generating a class of waveriders known as "starbodies" is presented. A complete analysis is performed of asymmetric starbody forms and compared to a better understood parameterization, "osculating cone" waveriders. This analysis includes characterization of stability behavior, a critical discipline within hypersonic flight. It is shown that asymmetric starbodies have significant stability improvement with only a 10% reduction in the lift-to-drag ratio. By combining the optimization of both the shape of the vehicle and the trajectory it flies, much is learned about the benefit that can be expected from lifting aero-assist missions. While previous studies have conceptually proven the viability, this work provides thorough quantification of the

  10. Studies on thermal analysis and optical parameters of Cu doped poly(vinyl acetate)/polyindole composites

    Science.gov (United States)

    Bhagat, D. J.; Dhokane, G. R.

    2015-05-01

    This article reports investigation on optical parameters and thermal analysis of Cu doped poly(vinyl acetate)/polyindole composites using cupric chloride as an oxidant. The study's complex optical parameters were determined through ultraviolet-visible (UV-vis) spectroscopy. Thermal analysis was done through thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). The optical band gap values were found in the range 3.4381-4.8646 eV that reflects that synthesized composites have the potential to have application in optical devices and solar cells. The optical conductivity of composites is calculated to be 1.608 × 107 S-1.

  11. Carrier concentration effect and other structure-related parameters on lattice thermal conductivity of Si nanowires

    Indian Academy of Sciences (India)

    IBRAHIM N QADER; M S OMAR

    2017-06-01

    Lattice thermal conductivity (LTC) of Si bulk and nanowires (NWs) with diameter 22, 37, 50, 56, 98 and 115 nm was investigated in the temperature range 3–300 K using a modified Callaway model that contains both longitudinal and transverse modes. Using proper equations, mean bond length, lattice parameter, unit cell volume, mass density, melting temperature, longitudinal and transverse Debye temperature and group velocity for all transverse and longitudinal modes were calculated for each NW diameter mentioned. Surface roughness, Gruneisen parameter and impurity were used as adjustable parameters to fit theoretical results with experimental curves. In addition, values of electron concentration and dislocation density were determined. There are some phonon scattering mechanisms assumed, which are Umklapp and normal processes, imperfections, phonon confinement, NW boundaries, electrons scattering and dislocation. Dislocationdensity less than 10$^{14}$ m$^{−2}$ for NWs and 10$^{12}$ m$^{−2}$ for bulk has no effect on LTC. Also, electron concentration less than 10$^{22}$ m$^{−3}$ for NWs and 10$^{16}$ m$^{−3}$ for the bulk has no effect. On increasing dislocation density and electron concentration, LTC comparably decreases.

  12. Aero-Thermo-Dynamic Mass Analysis

    Science.gov (United States)

    Shiba, Kota; Yoshikawa, Genki

    2016-07-01

    Each gas molecule has its own molecular weight, while such a microscopic characteristic is generally inaccessible, and thus, it is measured indirectly through e.g. ionization in conventional mass analysis. Here, we present a novel approach to the direct measurement of molecular weight through a nanoarchitectonic combination of aerodynamics, thermodynamics, and mechanics, transducing microscopic events into macroscopic phenomena. It is confirmed that this approach can provide molecular weight of virtually any gas or vaporizable liquid sample in real-time without ionization. Demonstrations through analytical calculations, numerical simulations, and experiments verify the validity and versatility of the novel mass analysis realized by a simple setup with a flexible object (e.g. with a bare cantilever and even with a business card) placed in a laminar jet. Owing to its unique and simple working principle, this aero-thermo-dynamic mass analysis (AMA) can be integrated into various analytical devices, production lines, and consumer mobile platforms, opening new chapters in aerodynamics, thermodynamics, mechanics, and mass analysis.

  13. Kinetic parameters of the thermal degradation of the PP and nondegraded and degraded HDPE blends

    Energy Technology Data Exchange (ETDEWEB)

    Albano, C.; Freitas, E. [Universidad Central de Venezuela, Caracas (Venezuela)

    1996-12-31

    We study the thermodegradative behavior of PP, of non-degraded and degraded HDPE and their blends, in order to analyze the thermal stability of such materials. Van-Krevelen (V-K), Coats-Redfern (C-R) and Horowitz-Metzger (H-M) integral methods as well as the Freeman-Carroll (F-C) differential one, were used to determine the kinetic parameters. The activation energy (E{sub a}) obtained for the PP mixed with non-degraded HDPE (5 to 50%) is lower than the E{sub a} correspondent to pure polymers and does not depend on the HDPE concentration. Blends of degraded materials, show an approximate value of E{sub a} of 200 kJ/mol for mixtures with concentrations by weight of HDPE up to 20%, but its value decreases drastically with higher concentrations. 11 refs., 2 tabs.

  14. Narrow size distributed Ag nanoparticles grown by spin coating and thermal reduction: effect of processing parameters

    Science.gov (United States)

    Ansari, A. A.; Sartale, S. D.

    2016-08-01

    A simple method to grow uniform sized Ag nanoparticles with narrow size distribution on flat support (glass and Si substrates) via spin coating of Ag+ ions (AgNO3) solution followed by thermal reduction in H2 is presented. These grown nanoparticles can be used as model catalytic system to study size dependent oxygen reduction reaction (ORR) activity. Ag nanoparticles formation was confirmed by local surface plasmon resonance and x-ray photoelectron spectroscopy measurements. Influences of process parameters (revolution per minute (rpm), ramp and salt concentration) on grown Ag nanoparticles size, density and size uniformity are studied. With increase in rpm and ramp the size decreases and the particle number density increases, whereas the size dispersion improves. The catalytic activity of the grown Ag particles for ORR is studied and it is found that the catalytic performance is dependent on the size as well as the number density of the grown Ag nanoparticles.

  15. Estimating Parameters of Delaminations in GRP Pipes Using Thermal NDE and ANN

    Science.gov (United States)

    Vijayaraghavan, G. K.; Majumder, M. C.; Ramachandran, K. P.; Muruganandam, A.; Govindarajan, L.

    2010-10-01

    Thermographic Non-Destructive Evaluation (TNDE) is one of the techniques that have been widely used over the decades to evaluate the integrity of structures. To meet the increased demand for robust and effective inspection in complex TNDE tasks, Artificial Neural Networks (ANNs) have been recently deployed in many problems. The aim of the paper is to adopt an inverse technique using ANNs in the field of TNDE to estimate various parameters of delamination in Glass Reinforced Polymer (GRP) pipes by supplying thermal contrast evolution data as input. A Radial Basis Network (RBN) is employed with 80 input and 3 output neurons. The estimation capability of the network was evaluated with the data obtained from numerical simulations. The overall absolute errors show that the estimation capability of ANN is good.

  16. Influence of process parameters on thermal-rate treatment of ZA42 alloy

    Institute of Scientific and Technical Information of China (English)

    李成栋; 田学雷; 赵梅; 耿浩然

    2002-01-01

    Sand casting process and directional solidification technique combining thermal-rate treatment(TRT) were used. The influence of process parameters on TRT was investigated according to the values of impact toughness. At the same time, the mechanism of TRT was discussed. The results showed that TRT can improve the impact toughness of this alloy, while the hardness is basically constant. The time of heat preservation should not be more than 5min. Different forms of cooling intensification additive have different effects among which the zinc ingot solidified in graphite mold is the best one that can improve impact toughness of samples by more than 80%. With increasing the cooling temperature, the value of α(Al) crystal lattice constant increases. The element Sb has negative effect on TRT.

  17. Selection of Weather Parameters for Air-Conditioning System Design for Buildings with Long Thermal Lag

    Institute of Scientific and Technical Information of China (English)

    GE Lian-feng; LEI Ming; CHEN You-ming

    2009-01-01

    Two building factors-a longer thermal lag of more than one hour for building envelops and a lag of indoor radiation to convert into cooling load-have impact on the instantaneous heat input and instantaneous cooling load.So the two factors should be taken into account when selecting the weather parameters for air-con-ditioning system design.This paper developed a new statistic method for the rational selection of coincident solar irradiance,dry-bulb and wet-bulb temperatures.The method was applied to historic weather records of 25 years in Hong Kong to generate coincident design weather data.And the results show that traditional design solar irra-diance,dry-bulb and wet-bulb temperatures may be significantly overestimated in many conditions,and the de-sign weather data for the three different constructions is not kept constant.

  18. DEVICE FOR MEASURING OF THERMAL LENS PARAMETERS IN LASER ACTIVE ELEMENTS WITH A PROBE BEAM METHOD

    Directory of Open Access Journals (Sweden)

    A. N. Zakharova

    2015-01-01

    Full Text Available We have developed a device for measuring of parameters of thermal lens (TL in laser active elements under longitudinal diode pumping. The measurements are based on the probe beam method. This device allows one to determine sign and optical power of the lens in the principal meridional planes, its sensitivity factor with respect to the absorbed pump power and astigmatism degree, fractional heat loading which make it possible to estimate integral impact of the photoelastic effect to the formation of TL in the laser element. The measurements are performed in a linearly polarized light at the wavelength of 532 nm. Pumping of the laser element is performed at 960 nm that makes it possible to study laser materials doped with Yb3+ and (Er3+, Yb3+ ions. The precision of measurements: for sensitivity factor of TL – 0,1 m-1/W, for astigmatism degree – 0,2 m-1/W, for fractional heat loading – 5 %, for the impact of the photoelastic effect – 0,5 × 10-6 K-1. This device is used for characterization of thermal lens in the laser active element from an yttrium vanadate crystal, Er3+,Yb3+:YVO .

  19. DAF optimization using Taguchi methods and the effect of thermal cycling parameters on DNA amplification.

    Science.gov (United States)

    Caetano-Anollés, G

    1998-09-01

    Taguchi methods, which are widely applied in industrial process design, were used to optimize DNA amplification finger-printing (DAF). Quadratic loss functions that penalize deviations from prediction values and L9 (3(4)) and L18 (3(8)) orthogonal arrays revealed effects and interactions of amplification reaction components and thermal cycling parameters. Analysis of variance (ANOVA) decomposed the contribution of individual factors to the experimental response (amplification yield and product number), while verification experiments established that optimum conditions were predictable, verifiable and reproducible. While several amplification components (primer, magnesium and enzyme) conditioned the amplification reaction, annealing temperature and time were the only important thermal cycling contributing factors. The Taguchi strategy defined a robust and transportable amplification protocol based on high annealing temperatures (typically 48 degrees C) and primer concentrations (typically 8 microM), which can be applied to the fingerprinting of a wide range of DNA templates of plant and fungal origin. The general strategy of robust experimental design holds potential as an optimization tool for other methods in molecular biology.

  20. Fundamental approaches for analysis thermal hydraulic parameter for Puspati Research Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, Zaredah, E-mail: zaredah@nm.gov.my; Lanyau, Tonny Anak, E-mail: tonny@nm.gov.my; Farid, Mohamad Fairus Abdul; Kassim, Mohammad Suhaimi [Reactor Technology Centre, Technical Support Division, Malaysia Nuclear Agency, Ministry of Science, Technology and Innovation, Bangi, 43000, Kajang, Selangor Darul Ehsan (Malaysia); Azhar, Noraishah Syahirah [Universiti Teknologi Malaysia, 80350, Johor Bahru, Johor Darul Takzim (Malaysia)

    2016-01-22

    The 1-MW PUSPATI Research Reactor (RTP) is the one and only nuclear pool type research reactor developed by General Atomic (GA) in Malaysia. It was installed at Malaysian Nuclear Agency and has reached the first criticality on 8 June 1982. Based on the initial core which comprised of 80 standard TRIGA fuel elements, the very fundamental thermal hydraulic model was investigated during steady state operation using the PARET-code. The main objective of this paper is to determine the variation of temperature profiles and Departure of Nucleate Boiling Ratio (DNBR) of RTP at full power operation. The second objective is to confirm that the values obtained from PARET-code are in agreement with Safety Analysis Report (SAR) for RTP. The code was employed for the hot and average channels in the core in order to calculate of fuel’s center and surface, cladding, coolant temperatures as well as DNBR’s values. In this study, it was found that the results obtained from the PARET-code showed that the thermal hydraulic parameters related to safety for initial core which was cooled by natural convection was in agreement with the designed values and safety limit in SAR.

  1. Combined Aero and Underhood Thermal Analysis for Heavy Duty Trucks

    Energy Technology Data Exchange (ETDEWEB)

    Vegendla, Prasad [Argonne National Lab. (ANL), Argonne, IL (United States); Sofu, Tanju [Argonne National Lab. (ANL), Argonne, IL (United States); Saha, Rohit [Cummins Inc., Columbus, IN (United States); Madurai Kumar, Mahesh [Cummins Inc., Columbus, IN (United States); Hwang, L. K [Cummins Inc., Columbus, IN (United States)

    2017-01-31

    Aerodynamic analysis of the medium-duty delivery truck was performed to achieve vehicle design optimization. Three dimensional CFD simulations were carried out for several improved designs, with a detailed external component analysis of wheel covers, side skirts, roof fairings, and rounded trailer corners. The overall averaged aerodynamics drag reduction through the design modifications were shown up to 22.3% through aerodynamic considerations alone, which is equivalent to 11.16% fuel savings. The main identified fuel efficiencies were based on second generation devices, including wheel covers, side skirts, roof fairings, and rounded trailer corners. The important findings of this work were; (i) the optimum curvature radius of the rounded trailer edges found to be 125 mm, with an arc length of 196.3 mm, (ii) aerodynamic drag reduction increases with dropping clearance of side skirts between wheels and ground, and (iii) aerodynamic drag reduction increases with an extension of front bumper towards the ground.

  2. Qualification of Indigenously Developed Special Coatings for Aero-Engine Components

    Directory of Open Access Journals (Sweden)

    V. Sambasiva Rao

    1999-10-01

    Full Text Available The demand for higher performance and reliability of aero-engiaes necessitates its components to worksatisfactorily under severe operating conditions. The durability of various components in these environmentis often enhanced by applying suitable coatings. The development of new materials/processing methods andalso various coatings to protect the components have been driven by the ever-increasing severity of theaero-engine internal environment. While the selection of a coating is dictated by the operating conditionsand the nature of the environment and also on the substrate, the durability of the coating depends uponthe mode of degradation of the coating and substrate in service.Though certification of an aero-engine after developmt obviously includes: validation of the componentsand its coatings, indigenous substitution of an already-qualified component system requires a re-orientationof the qualification methodology. This paper describes an approach for qualification of indigenously developedspecial coatings processes for application on aero-engine components. This approach has been adoptedsuccesshlly in validating several indigenous coatingslpmcesses, viz, aluminium-silicon diffusion coating appliedby pack cementation for oxidationhot comsion resistance, cobalt-chromium carbide coating by electrodepositionfor wear resistance, chromium carbide-nickel chromium coating applied by detonation gun and yttria-stabilisedzirconia thermal barrier coating applied by plasma spray.The approaih consists of a series of validation tests configured to assess the coating-substrate system.The rationale in evolving the qualification tests based on the type of coating, coating process, operating conditionsfor the components, probable failure modes and coating-base metal interaction, are described. In addition,comparison of the test results obtained on the test specimens coated with indigenously developed coatingsand imported coatings is also enumerated to show

  3. Reconstruction of the aero-mixture channels of the pulverized coal plant of the 100MW power plant unit

    Directory of Open Access Journals (Sweden)

    Ivanovic Vladan B.

    2011-01-01

    Full Text Available After the last revitalization of thermal power block of 100 MW in TPP “Kostolac A”, made in the year 2004, during the operation of the plant, pulverized coal deposition often occurred in horizontal sections of the aero-mixture channels. Deposition phenomenon manifested itself in places ahead of spherical compensators in the direction of flow of pulverized coal to the burners, due to unfavorable configuration of these channels. Coal dust deposited in the channels dried and spontaneously combusted, causing numerous damage to channels and its isolation as well as the frequent stoppage of the operation for necessary interventions. The paper presents the original solution of reconstruction of aero-mixture channels which prevented deposition of coal dust and its eventual ignition. In this way the reliability of the mill plant is maximized and higher availability of boiler and block as a whole is achieved.

  4. Experimental Technique of Titanium Fire in Aero-engine

    Directory of Open Access Journals (Sweden)

    MI Guangbao

    2016-06-01

    Full Text Available Titanium fire is the typical catastrophic fault in the aero-engine. Aiming at the urgent demand for experimental technique of titanium fire from advanced high thrust-weight ratio aero-engine, the combustion technology and theory of titanium alloy based on friction oxygen concentration method (FOC were systematically studied. The evaluation method of fireproof property and the friction ignition model were built, and the fireproof mechanism was illustrated. By generalizing recent progress in experimental technique of titanium fire from three levels, including evolutionary rule, mechanism and prevention and control technology, the ideas and directions of experimental technique associated with the application research of titanium fire in the future were proposed, namely overall evaluation of fireproof property close to air flow environment of the aero-engine, prediction model of fireproof property and experimental verification of fireproof technique under the air flow environment of aero-engine. It is necessary to establish the prevention system of titanium fire in aero-engine, which contributes to the realization of "full titanium" in compressor and to the increase of high thrust-weight ratio.

  5. Aero-Optic Evaluation Center (AOEC), Large Energy National Shock (LENS) Tunnels I & II

    Data.gov (United States)

    Federal Laboratory Consortium — The AOEC facility provides world class capability for aero-thermo-chemical, aerooptics and aero-propulsion testing in the Mach number range from 2.5 to 15 using the...

  6. Ground-based infrared surveys: imaging the thermal fields at volcanoes and revealing the controlling parameters.

    Science.gov (United States)

    Pantaleo, Michele; Walter, Thomas

    2013-04-01

    Temperature monitoring is a widespread procedure in the frame of volcano hazard monitoring. Indeed temperature changes are expected to reflect changes in volcanic activity. We propose a new approach, within the thermal monitoring, which is meant to shed light on the parameters controlling the fluid pathways and the fumarole sites by using infrared measurements. Ground-based infrared cameras allow one to remotely image the spatial distribution, geometric pattern and amplitude of fumarole fields on volcanoes at metre to centimetre resolution. Infrared mosaics and time series are generated and interpreted, by integrating geological field observations and modeling, to define the setting of the volcanic degassing system at shallow level. We present results for different volcano morphologies and show that lithology, structures and topography control the appearance of fumarole field by the creation of permeability contrasts. We also show that the relative importance of those parameters is site-dependent. Deciphering the setting of the degassing system is essential for hazard assessment studies because it would improve our understanding on how the system responds to endogenous or exogenous modification.

  7. Prediction of the effect of defect parameters on the thermal contrast evolution during flash thermography by finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Ziqiao; Yuan, Maodan; Wu, Hu; Zhang, Jianjai; Kim, Hak Joon; Song, Sung Jin [School of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

    2014-02-15

    A 3D model based on the finite element method (FEM) was built to simulate the infrared thermography (IRT) inspection process. Thermal contrast is an important parameter in IRT and was proven to be a function of defect parameters. Parametric studies were conducted on internal defects with different depths, thicknesses, and orientations. Thermal contrast evolution profiles with respect to the time of the defect and host material were obtained through numerical simulation. The thermal contrast decreased with defect depth and slightly increased with defect thickness. Different orientations of thin defects were detected with IRT, but doing so for thick defects was difficult. These thermal contrast variations with the defect depth, thickness, and orientation can help in optimizing the experimental process and interpretation of data from IRT.

  8. Experimental Determination of the Thermal Parameters of Carbon Fiber-Composite Materials Exposed to Fire by Infrared Imaging Pulse Thermography

    Science.gov (United States)

    Sánchez-Carballido, S.; Justo-María, C.; Meléndez, J.; Cortés, F.; López, F.; López del Cerro, F. J.

    2013-09-01

    A new procedure adapted from the classical one performed by Parker et al. has been developed to extend it to insulating plates (carbon fiber-reinforced composites). The measurement system consists of an infrared camera synchronized with a flash lamp. This method has been implemented to obtain the thermal parameters of the samples in different states of degradation by fire. The method is based on experimental-theory adjustment to obtain the intrinsic thermal parameters: thermal diffusivity, thermal conductivity, and volumetric heat capacity. In addition, the method has required development of a theoretical model accounting for the cooling losses significant for insulating plates. The results have been validated by comparison between the experimental data and those provided by a heat transfer model.

  9. SIERRA/Aero User Manual Version 4.44

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal/Fluid Team

    2017-04-01

    SIERRA/Aero is a compressible fluid dynamics program intended to solve a wide variety compressible fluid flows including transonic and hypersonic problems. This document describes the commands for assembling a fluid model for analysis with this module, henceforth referred to simply as Aero for brevity. Aero is an application developed using the SIERRA Toolkit (STK). The intent of STK is to provide a set of tools for handling common tasks that programmers encounter when developing a code for numerical simulation. For example, components of STK provide field allocation and management, and parallel input/output of field and mesh data. These services also allow the development of coupled mechanics analysis software for a massively parallel computing environment. In the definitions of the commands that follow, the term Real_Max denotes the largest floating point value that can be represented on a given computer. Int_Max is the largest such integer value.

  10. SIERRA/Aero Theory Manual Version 4.44

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal/Fluid Team

    2017-04-01

    SIERRA/Aero is a two and three dimensional, node-centered, edge-based finite volume code that approximates the compressible Navier-Stokes equations on unstructured meshes. It is applicable to inviscid and high Reynolds number laminar and turbulent flows. Currently, two classes of turbulence models are provided: Reynolds Averaged Navier-Stokes (RANS) and hybrid methods such as Detached Eddy Simulation (DES). Large Eddy Simulation (LES) models are currently under development. The gas may be modeled either as ideal, or as a non-equilibrium, chemically reacting mixture of ideal gases. This document describes the mathematical models contained in the code, as well as certain implementation details. First, the governing equations are presented, followed by a description of the spatial discretization. Next, the time discretization is described, and finally the boundary conditions. Throughout the document, SIERRA/ Aero is referred to simply as Aero for brevity.

  11. Vehicle Health Management Communications Requirements for AeroMACS

    Science.gov (United States)

    Kerczewski, Robert J.; Clements, Donna J.; Apaza, Rafael D.

    2012-01-01

    As the development of standards for the aeronautical mobile airport communications system (AeroMACS) progresses, the process of identifying and quantifying appropriate uses for the system is progressing. In addition to defining important elements of AeroMACS standards, indentifying the systems uses impacts AeroMACS bandwidth requirements. Although an initial 59 MHz spectrum allocation for AeroMACS was established in 2007, the allocation may be inadequate; studies have indicated that 100 MHz or more of spectrum may be required to support airport surface communications. Hence additional spectrum allocations have been proposed. Vehicle health management (VHM) systems, which can produce large volumes of vehicle health data, were not considered in the original bandwidth requirements analyses, and are therefore of interest in supporting proposals for additional AeroMACS spectrum. VHM systems are an emerging development in air vehicle safety, and preliminary estimates of the amount of data that will be produced and transmitted off an aircraft, both in flight and on the ground, have been prepared based on estimates of data produced by on-board vehicle health sensors and initial concepts of data processing approaches. This allowed an initial estimate of VHM data transmission requirements for the airport surface. More recently, vehicle-level systems designed to process and analyze VHM data and draw conclusions on the current state of vehicle health have been undergoing testing and evaluation. These systems make use of vehicle system data that is mostly different from VHM data considered previously for airport surface transmission, and produce processed system outputs that will be also need to be archived, thus generating additional data load for AeroMACS. This paper provides an analysis of airport surface data transmission requirements resulting from the vehicle level reasoning systems, within the context of overall VHM data requirements.

  12. Methodologies for predicting the part-load performance of aero-derivative gas turbines

    DEFF Research Database (Denmark)

    Haglind, Fredrik; Elmegaard, Brian

    2009-01-01

    on methodologies for predicting part-load performance of aero-derivative gas turbines. Two different design models – one simple and one more complex – are created. Subsequently, for each of these models, the part-load performance is predicted using component maps and turbine constants, respectively. Comparisons...... with manufacturer data are made. With respect to the design models, the simple model, featuring a compressor, combustor and turbines, results in equally good performance prediction in terms of thermal efficiency and exhaust temperature as does a more complex model. As for part-load predictions, the results suggest...... that the mass flow and pressure ratio characteristics can be well predicted with both methods. The thermal efficiency and exhaust temperature, however, are not well predicted below 60–70% load when using turbine constants and assuming constant efficiencies for turbomachinery....

  13. Characteristic diode parameters in thermally annealed Ni/p-InP contacts

    Science.gov (United States)

    Turut, A.; Ejderha, K.; Yildirim, N.; Abay, B.

    2016-04-01

    The Ni/p-InP Schottky diodes (SDs) have been prepared by DC magnetron sputtering deposition. After the diode fabrication, they have been thermally annealed at 700 °C for 1 min in N2 atmosphere. Then, the current-voltage characteristics of the annealed and non-annealed (as-deposited) SDs have been measured in the measurement temperature range of 60-400 K with steps of 20 K under dark conditions. After 700 °C annealing, an improvement in the ideality factor value has been observed from 60 to 200 K and the barrier height (BH) value approximately has remained unchanged in the measurement temperature range of 200-400 K. The BH of the annealed diode has decreased obeying the double-Gaussian distribution (GD) of the BHs with decreasing measurement temperature from 200 to 60 K. The BH for the as-deposited diode has decreased with decreasing temperature obeying the single-GD over the whole measurement temperature range. An effective Richardson constant value of 54.21 A/cm2K2 for the as-deposited SD has been obtained from the modified Richardson plot by the single-GD plot, which is in very close agreement with the value of 60 A/K2cm2 for p-type InP. The series resistance value of the annealed SD is lower than that of the non-annealed SD at each temperature and approximately has remained unchanged from 140 to 240 K. Thus, it can be said that an improvement in the diode parameters has been observed due to the thermal annealing at 700 °C for 1 min in N2 atmosphere.

  14. Modeling and Simulation of the Thermal Runaway Behavior of Cylindrical Li-Ion Cells—Computing of Critical Parameters

    Directory of Open Access Journals (Sweden)

    Andreas Melcher

    2016-04-01

    Full Text Available The thermal behavior of Li-ion cells is an important safety issue and has to be known under varying thermal conditions. The main objective of this work is to gain a better understanding of the temperature increase within the cell considering different heat sources under specified working conditions. With respect to the governing physical parameters, the major aim is to find out under which thermal conditions a so called Thermal Runaway occurs. Therefore, a mathematical electrochemical-thermal model based on the Newman model has been extended with a simple combustion model from reaction kinetics including various types of heat sources assumed to be based on an Arrhenius law. This model was realized in COMSOL Multiphysics modeling software. First simulations were performed for a cylindrical 18650 cell with a L i C o O 2 -cathode to calculate the temperature increase under two simple electric load profiles and to compute critical system parameters. It has been found that the critical cell temperature T crit , above which a thermal runaway may occur is approximately 400 K , which is near the starting temperature of the decomposition of the Solid-Electrolyte-Interface in the anode at 393 . 15 K . Furthermore, it has been found that a thermal runaway can be described in three main stages.

  15. Lattice variation and thermal parameters of NiMg1–SO4 7H2O single crystals

    Indian Academy of Sciences (India)

    M Theivanayagom; C Mahadevan

    2001-10-01

    NiMg1–SO4.7H2O single crystals were grown by the slow evaporation method from aqueous solutions. Density was measured by the floatation method. X-ray diffraction data were collected for powder samples and used for the estimation of lattice variation and thermal parameters like Debye–Waller factor, mean-square amplitude of vibration and Debye temperature. Lattice volumes approximately obey a relation similar to Retger’s rule. Values of thermal parameters do not follow any particular order with composition. The results obtained are reported.

  16. Study of the dependence the thermal conductivity of nanofluids on different parameters

    Science.gov (United States)

    Pryazhnikov, M. I.; Minakov, A. V.; Guzei, D. V.; Rudyak, V. Ya

    2016-10-01

    The paper presents the results of systematic measurements of the thermal conductivity coefficient of nanofluids at room temperature. It is shown that the thermal conductivity of all considered nanofluids depend on concentration, nanopartical size, as well as the base fluid properties. It was revealed that thermal conductivity coefficient of nanofluids increases with increasing concentration and size of nanoparticles.

  17. Aero-servo-viscoelasticity theory: Lifting surfaces, plates, velocity transients, flutter, and instability

    Science.gov (United States)

    Merrett, Craig G.

    indicates that the flutter condition should be taken when simple harmonic motion occurs and certain additional velocity derivatives are satisfied. 3. The viscoelastic material behavior imposes a flutter time indicating that the presence of flutter should be verified for the entire life time of a flight vehicle. 4. An expanded definition for instability of a lifting surface or panel. Traditionally, instability is treated as a static phenomenon. The static case is only a limiting case of dynamic instability for a viscoelastic structure. Instability occurs when a particular combination of flight velocity and time are reached leading to growing displacements of the structure. 5. The inclusion of flight velocity transients that occur during maneuvers. Two- and three-dimensional unsteady incompressible and compressible aerodynamics were reformulated for a time dependent velocity. The inclusion of flight velocity transients does affect the flutter and instability conditions for a lifting surface and a panel. The applications of aero-servo-viscoelasticity are to aircraft design, wind turbine blades, submarine's stealth coatings and hulls, and land transportation to name a few examples. One caveat regarding this field of research is that general predictions for an application are not always possible as the stability of a structure depends on the phase relations between the various parameters such as mass, stiffness, damping, and the aerodynamic loads. The viscoelastic material parameters in particular alter the system parameters in directions that are difficult to predict. The inclusion of servo controls permits an additional design factor and can improve the performance of a structure beyond the native performance; however over-control is possible so a maximum limit to useful control does exist. Lastly, the number of material and control parameters present in aero-servo-viscoelasticity are amenable to optimization protocols to produce the optimal structure for a given mission.

  18. Vortex-Based Aero- and Hydrodynamic Estimation

    Science.gov (United States)

    Hemati, Maziar Sam

    Flow control strategies often require knowledge of unmeasurable quantities, thus presenting a need to reconstruct flow states from measurable ones. In this thesis, the modeling, simulation, and estimator design aspects of flow reconstruction are considered. First, a vortex-based aero- and hydrodynamic estimation paradigm is developed to design a wake sensing algorithm for aircraft formation flight missions. The method assimilates wing distributed pressure measurements with a vortex-based wake model to better predict the state of the flow. The study compares Kalman-type algorithms with particle filtering algorithms, demonstrating that the vortex nonlinearities require particle filters to yield adequate performance. Furthermore, the observability structure of the wake is shown to have a negative impact on filter performance regardless of the algorithm applied. It is demonstrated that relative motions can alleviate the filter divergence issues associated with this observability structure. In addition to estimator development, the dissertation addresses the need for an efficient unsteady multi-body aerodynamics testbed for estimator and controller validation studies. A pure vortex particle implementation of a vortex panel-particle method is developed to satisfy this need. The numerical method is demonstrated on the impulsive startup of a flat plate as well as the impulsive startup of a multi-wing formation. It is clear, from these validation studies, that the method is able to accommodate the unsteady wake effects that arise in formation flight missions. Lastly, successful vortex-based estimation is highly dependent on the reliability of the low-order vortex model used in representing the flow of interest. The present treatise establishes a systematic framework for vortex model improvement, grounded in optimal control theory and the calculus of variations. By minimizing model predicted errors with respect to empirical data, the shortcomings of the baseline vortex model

  19. Anharmonic interatomic force constants and thermal conductivity from Grüneisen parameters: An application to graphene

    Science.gov (United States)

    Lee, Ching Hua; Gan, Chee Kwan

    2017-07-01

    Phonon-mediated thermal conductivity, which is of great technological relevance, arises due fundamentally to anharmonic scattering from interatomic potentials. Despite its prevalence, accurate first-principles calculations of thermal conductivity remain challenging, primarily due to the high computational cost of anharmonic interatomic force constant (IFC) calculations. Meanwhile, the related anharmonic phenomenon of thermal expansion is much more tractable, being computable from the Grüneisen parameters associated with phonon frequency shifts due to crystal deformations. In this work, we propose an approach for computing the largest cubic IFCs from the Grüneisen parameter data. This allows an approximate determination of the thermal conductivity via a much less expensive route. The key insight is that although the Grüneisen parameters cannot possibly contain all the information on the cubic IFCs, being derivable from spatially uniform deformations, they can still unambiguously and accurately determine the largest and most physically relevant ones. By fitting the anisotropic Grüneisen parameter data along judiciously designed deformations, we can deduce (i.e., reverse-engineer) the dominant cubic IFCs and estimate three-phonon scattering amplitudes. We illustrate our approach by explicitly computing the largest cubic IFCs and thermal conductivity of graphene, especially for its out-of-plane (flexural) modes that exhibit anomalously large anharmonic shifts and thermal conductivity contributions. Our calculations on graphene not only exhibit reasonable agreement with established density-functional theory results, but they also present a pedagogical opportunity for introducing an elegant analytic treatment of the Grüneisen parameters of generic two-band models. Our approach can be readily extended to more complicated crystalline materials with nontrivial anharmonic lattice effects.

  20. Reliability analysis of aero-engine blades considering nonlinear strength degeneration

    Institute of Scientific and Technical Information of China (English)

    Lin Jiewei; Zhang Junhong; Yang Shuo; Bi Fengrong

    2013-01-01

    To comprehensively consider the effects of strength degeneration and failure correlation,an improved stress-strength interference (SSI) model is proposed to analyze the reliability of aeroengine blades with the fatigue failure mode.Two types of TC4 alloy experiments are conducted for the study on the damage accumulation law.All the parameters in the nonlinear damage model are obtained by the tension-compression fatigue tests,and the accuracy of the nonlinear damage model is verified by the damage tests.The strength degeneration model is put forward on the basis of the Chaboche nonlinear damage theory and the Griffith fracture criterion,and determined by measuring the fatigue toughness during the tests.From the comparison of two kinds of degeneration models based on the Miner's linear law and the nonlinear damage model respectively,the nonlinear model has a significant advantage on prediction accuracy especially in the later period of life.A time-dependent SSI reliability model is established.By computing the stress distribution using the finite element (FE) technique,the reliability of a single blade during the whole service life is obtained.Considering the failure correlation of components,a modified reliability model of aero-engine blades with common cause failure (CCF) is presented.It shows a closer and more reasonable process with the actual working condition.The improved reliability model is illustrated to be applied to aero-engine blades well,and the approach purposed in this paper is suitable for any actual machinery component of aero-engine rotor systems.

  1. Influence of dimension parameters of the gravity heat pipe on the thermal performance

    Science.gov (United States)

    Kosa, Ľuboš; Nemec, Patrik; Jobb, Marián; Malcho, Milan

    2016-06-01

    Currently the problem with the increasing number of electronic devices is a problem with the outlet Joule heating. Joule heating, also known as ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor releases heat. Perfect dustproof cooling of electronic components ensures longer life of the equipment. One of more alternatives of heat transfer without the using of mechanical equipment is the use of the heat pipe. Heat pipes are easy to manufacture and maintenance of low input investment cost. The advantage of using the heat pipe is its use in hermetic closed electronic device which is separated exchange of air between the device and the environment. This experiment deals with the influence of changes in the working tube diameter and changing the working fluid on performance parameters. Changing the working fluid and the tube diameter changes the thermal performance of the heat pipe. The result of this paper is finding the optimal diameter with ideal working substance for the greatest heat transfer for 1cm2 sectional area tube.

  2. Blackness coefficients, effective diffusion parameters, and control rod worths for thermal reactors

    Energy Technology Data Exchange (ETDEWEB)

    Bretscher, M.M.

    1984-09-01

    Simple diffusion theory cannot be used to evaluate control rod worths in thermal reactors because of the strongly absorbing character of the control material. However, good results can be obtained from a diffusion calculation by representing the absorber slab by means of a suitable pair of internal boundary conditions, ..cap alpha.. and ..beta.., which are ratios of neutron flux to neutron current. Methods for calculating ..cap alpha.. and ..beta.. in the P/sub 1/, P/sub 3/, and P/sub 5/ approximations, with and without scattering, are presented. By appropriately weighting the fine-group blackness coefficients, broad group values, <..cap alpha..> and <..beta..>, are obtained. The technique is applied to the calculation of control rod worths of Cd, Ag-In-Cd, and Hf control elements. Results are found to compare very favorably with detailed Monte Carlo calculations. For control elements whose geometry does not permit a thin slab treatment, other methods are needed for determining the effective diffusion parameters. One such method is briefly discussed and applied to the calculation of control rod worths in the Ford Nuclear Reactor at the University of Michigan. Calculated and measured worths are found to be in good agreement.

  3. Image processing analysis of nuclear track parameters for CR-39 detector irradiated by thermal neutron

    Science.gov (United States)

    Al-Jobouri, Hussain A.; Rajab, Mustafa Y.

    2016-03-01

    CR-39 detector which covered with boric acid (H3Bo3) pellet was irradiated by thermal neutrons from (241Am - 9Be) source with activity 12Ci and neutron flux 105 n. cm-2. s-1. The irradiation times -TD for detector were 4h, 8h, 16h and 24h. Chemical etching solution for detector was sodium hydroxide NaOH, 6.25N with 45 min etching time and 60 C˚ temperature. Images of CR-39 detector after chemical etching were taken from digital camera which connected from optical microscope. MATLAB software version 7.0 was used to image processing. The outputs of image processing of MATLAB software were analyzed and found the following relationships: (a) The irradiation time -TD has behavior linear relationships with following nuclear track parameters: i) total track number - NT ii) maximum track number - MRD (relative to track diameter - DT) at response region range 2.5 µm to 4 µm iii) maximum track number - MD (without depending on track diameter - DT). (b) The irradiation time -TD has behavior logarithmic relationship with maximum track number - MA (without depending on track area - AT). The image processing technique principally track diameter - DT can be take into account to classification of α-particle emitters, In addition to the contribution of these technique in preparation of nano- filters and nano-membrane in nanotechnology fields.

  4. Coupling behavior between adhesive and abrasive wear mechanism of aero-hydraulic spool valves

    Institute of Scientific and Technical Information of China (English)

    Chen Yunxia; Gong Wenjun; Kang Rui

    2016-01-01

    Leakage due to wear is one of the main failure modes of aero-hydraulic spool valves. This paper established a practical coupling wear model for aero-hydraulic spool valves based on dynamic system modelling theory. Firstly, the experiment for wear mechanism verification proved that adhesive wear and abrasive wear did coexist during the working process of spool valves. Sec-ondly coupling behavior of each wear mechanism was characterized by analyzing actual time-variation of model parameters during wear evolution process. Meanwhile, Archard model and three-body abrasive wear model were utilized for adhesive wear and abrasive wear, respectively. Furthermore, their coupling wear model was established by calculating the actual wear volume. Finally, from the result of formal test, all the required parameters for our model were obtained. The relative error between model prediction and data of pre-test was also presented to verify the accuracy of model, which demonstrated that our model was useful for providing accurate prediction of spool valve’s wear life.

  5. An effect of heat insulation parameters on thermal losses of water-cooled roofs for secondary steelmaking electric arc furnaces

    Directory of Open Access Journals (Sweden)

    E. Mihailov

    2016-07-01

    Full Text Available The aim of this work is research in the insulation parameters effect on the thermal losses of watercooled roofs for secondary steelmaking electric arc furnaces. An analytical method has been used for the investigation in heat transfer conditions in the working area. The results of the research can be used to choose optimal cooling parameters and select a suitable kind of insulation for water-cooled surfaces.

  6. Stability and local bifurcation of parameter-excited vibration of pipes conveying pulsating fluid under thermal loading

    Institute of Scientific and Technical Information of China (English)

    Demin ZHAO; Jianlin LIU; C Q WU

    2015-01-01

    The parametric excited vibration of a pipe under thermal loading may occur because the fluid is often transported heatedly. The effects of thermal loading on the pipe stability and local bifurcations have rarely been studied. The stability and the local bifurcations of the lateral parametric resonance of the pipe induced by the pulsating fluid velocity and the thermal loading are studied. A mathematical model for a simply supported pipe is developed according to the Hamilton principle. Two partial differential equations describing the lateral and longitudinal vibration are obtained. The singularity theory is utilized to analyze the stability and the bifurcation of the system solutions. The transition sets and the bifurcation diagrams are obtained both in the unfolding parameter space and the physical parameter space, which can reveal the relationship between the thermal field parameter and the dynamic behaviors of the pipe. The frequency response and the relationship between the critical thermal rate and the pulsating fluid velocity are obtained. The numerical results demonstrate the accuracy of the single-mode expansion of the solution and the stability and local bifurcation analyses. It also confirms the existence of the chaos. The presented work can provide valuable information for the design of the pipeline and the controllers to prevent the structural instability.

  7. Thermal Regime and Meteorological Parameters Monitoring in Alpine Permafrost Rockwalls: the Aiguille du Midi

    Science.gov (United States)

    Morra di Cella, U.; Cremonese, E.; Deline, P.; Gruber, S.; Pogliotti, P.; Ravanel, L.

    2009-04-01

    During the last decades the alpine region has revealed to be extremely sensitive to ongoing increasing temperatures and permafrost has been identified as one of six cryospheric indicators of global climate change. In high-mountain regions the permafrost evidences are scarse and punctual, while its occurrence is wide and its distribution is mainly controlled by complex topography and ground cover condition. In such environment, steep bedrock slopes are abundant and contain a significant proportion of permafrost whose thermal response is very fast compared to permafrost in gentle morphology because of its less amount of ice content. Due to logistical problems like accessibility, costs, weather conditions, etc..., monitoring sites in such environments are few, while an increase of measurements of rockwall temperature and system energy balance is fundamental for the calibration and validation of both physical and statistical permafrost models. Started in the framework of the French-Italian project PERMAdataROC (www.fondazionemontagnasicura.org/multimedia/permadataroc/) and presently developped within the EU co-funded project PermaNET (www.permanet-alpinespace.eu), several monitoring sites have been equipped during the last years in the Western Alps from a collaboration of Swiss, French and Italian researchers, with the aim to cover the widest range of climatic, topographic, morphological and geological conditions. In such network, the Aiguille du Midì can be considered one of the most advanced site in high-mountain permafrost research thanks to the convergence of several instrumental approaches, but also a "cooperation laboratory" among different research groups. The site has been choosen because of its elevation, aspects variability, steep slopes and accessibility all over the year. In details, ARPA Valle d'Aosta in collaboration with University of Zurich started in 2006 the monitoring of rockwall thermal regimes and of some meteorological parameters on the different

  8. Global dust model intercomparison in AeroCom phase I

    NARCIS (Netherlands)

    Huneeus, N.; Schulz, M.; Balkanski, Y.; Griesfeller, J.; Krol, M.C.

    2011-01-01

    This study presents the results of a broad intercomparison of a total of 15 global aerosol models within the AeroCom project. Each model is compared to observations related to desert dust aerosols, their direct radiative effect, and their impact on the biogeochemical cycle, i.e., aerosol optical dep

  9. Generic methods for aero-engine exhaust emission prediction

    NARCIS (Netherlands)

    Shakariyants, S.A.

    2008-01-01

    In the thesis, generic methods have been developed for aero-engine combustor performance, combustion chemistry, as well as airplane aerodynamics, airplane and engine performance. These methods specifically aim to support diverse emission prediction studies coupled with airplane and engine simulation

  10. Simultaneous inversion of multiple land surface parameters from MODIS optical-thermal observations

    Science.gov (United States)

    Ma, Han; Liang, Shunlin; Xiao, Zhiqiang; Shi, Hanyu

    2017-06-01

    Land surface parameters from remote sensing observations are critical in monitoring and modeling of global climate change and biogeochemical cycles. Current methods for estimating land surface variables usually focus on individual parameters separately even from the same satellite observations, resulting in inconsistent products. Moreover, no efforts have been made to generate global products from integrated observations from the optical to Thermal InfraRed (TIR) spectrum. Particularly, Middle InfraRed (MIR) observations have received little attention due to the complexity of the radiometric signal, which contains both reflected and emitted radiation. In this paper, we propose a unified algorithm for simultaneously retrieving six land surface parameters - Leaf Area Index (LAI), Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), land surface albedo, Land Surface Emissivity (LSE), Land Surface Temperature (LST), and Upwelling Longwave radiation (LWUP) by exploiting MODIS visible-to-TIR observations. We incorporate a unified physical radiative transfer model into a data assimilation framework. The MODIS visible-to-TIR time series datasets include the daily surface reflectance product and MIR-to-TIR surface radiance, which are atmospherically corrected from the MODIS data using the Moderate Resolution Transmittance program (MODTRAN, ver. 5.0). LAI was first estimated using a data assimilation method that combines MODIS daily reflectance data and a LAI phenology model, and then the LAI was input to the unified radiative transfer model to simulate spectral surface reflectance and surface emissivity for calculating surface broadband albedo and emissivity, and FAPAR. LST was estimated from the MIR-TIR surface radiance data and the simulated emissivity, using an iterative optimization procedure. Lastly, LWUP was estimated using the LST and surface emissivity. The retrieved six parameters were extensively validated across six representative sites with

  11. Seasonal and Diurnal Thermal Performance of a Subtropical Extensive Green Roof: The Impacts of Background Weather Parameters

    Directory of Open Access Journals (Sweden)

    Lilliana L. H. Peng

    2015-08-01

    Full Text Available Most studies explored green-roof thermal effects on a few hot summer days based on short-term monitoring data. Few studies investigated the seasonal and diurnal patterns of thermal performance and associated weather effects. This research aims to address the following two questions: (1 how green-roof thermal performance varies with different season and time; and (2 to what extent can thermal performance be predicted by background weather parameters? A retrofitted extensive green roof was established on the top of a railway station in subtropical Hong Kong. Monitoring data covering a two-year period, one year before roof greening and one year after, were collected and analyzed. Results indicated notable seasonal and diurnal patterns of green-roof thermal performance. It exhibited cooling effects in spring, summer and fall, but warming effects in winter. The cooling effects were more pronounced in summer than spring and fall, on sunny days than rainy and cloudy days, and in nighttime than daytime. Air temperature, relative humidity, wind speed, solar radiation, and soil moisture could explain 83.6%–86% of the thermal effects’ variation. The multiple-regression models based on the five weather variables established in this study provide an uncomplicated and direct approach to predict the thermal performance of similar extensive green roofs in subtropical areas.

  12. Thermal and solvent effects on NMR spectroscopy parameters of a prototypical Chagas disease drug

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Full text. Hydrogen bonds in liquids can be of crucial importance for solvent effects in spectroscopy. We have herein computed the nuclear magnetic spin-spin coupling constants (SSCC) involving 15N and 1H nuclei motivated by the relevance of these couplings for the indirect detection of the 15N chemical shifts. Such nJ(N,H) couplings are now also taken as probes for obtaining structural information in proteins. In this work, we focus on the J-couplings; a complete analysis of the NMR spectral data for the compounds studied can be found in previous papers. Thermal and solvent effects on the SSCCs of metronidazole (1) were studied computationally with appropriate quantum-chemical methods. Metronidazole may serve as a model compound to investigate the influence of solvent molecules on the NMR spin-spin coupling constants in heterocyclic rings. We find a hydrogen bond between 1 and a solvent water molecule that is associated with a bond critical point between the imidazole N-3 atom and a water H atom. AIM analysis indicates this hydrogen bond to be mainly electrostatic in nature. Simple static SSCC calculations in vacuo underestimate the nJ(N-3,H) coupling constants because of the neglect of hydrogen bonding. PCM-based treatments perform reasonably well because of the electrostatic character of the hydrogen bond. For more reliable predictions, it is important to take into account the dynamics of the system and to include nearby solvent molecules explicitly. The reduction of the hyperconjugative interactions involving the sigma CH bond or the sigma {sup *}CH antibond (with the coupling nucleus H) that is found in solution appears to be correlated to the reduction of coupling pathways in the imidazole ring. Since nuclear spin orientation information is transferred electronically to the other nuclei in the molecule, experimentally determined J-couplings directly reflect the nature of the chemical bond involved.106,107 Unlike most other NMR properties, which can be

  13. Integrated evaluation of the geology, aero gamma spectrometry and aero magnetometry of the Sul-Riograndense Shield, southernmost Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, Leo A.; Savian, Jairo F., E-mail: leo.hartmann@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Instituto de Geociencias; Lopes, William R. [Servico Geologico do Brasil (CPRM), Porto Alegre, RS (Brazil). Gerencia de Geologia e Mineracao

    2016-03-15

    An integrated evaluation of geology, aero gamma spectrometry and aero magnetometry of the Sul-Riograndense Shield is permitted by the advanced stage of understanding of the geology and geochronology of the southern Brazilian Shield and a 2010 airborne geophysical survey. Gamma rays are registered from the rocks near the surface and thus describe the distribution of major units in the shield, such as the Pelotas batholith, the juvenile São Gabriel terrane, the granulite-amphibolite facies Taquarembo terrane and the numerous granite intrusions in the foreland. Major structures are also observed, e.g., the Dorsal de Cangucu shear. Magnetic signals register near surface crustal compositions (analytic signal) and total crust composition (total magnetic signal), so their variation as measured indicates either shallow or whole crustal structures. The Cacapava shear is outstanding on the images as is the magnetic low along the N-S central portion of the shield. These integrated observations lead to the deepening of the understanding of the largest and even detailed structures of the Sul-Riograndense Shield, some to be correlated to field geology in future studies. Most significant is the presence of different provinces and their limits depending on the method used for data acquisition - geology, aero gamma spectrometry or aero magnetometry. (author)

  14. Image processing analysis of nuclear track parameters for CR-39 detector irradiated by thermal neutron

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jobouri, Hussain A., E-mail: hahmed54@gmail.com; Rajab, Mustafa Y., E-mail: mostafaheete@gmail.com [Department of Physics, College of Science, AL-Nahrain University, Baghdad (Iraq)

    2016-03-25

    CR-39 detector which covered with boric acid (H{sub 3}Bo{sub 3}) pellet was irradiated by thermal neutrons from ({sup 241}Am - {sup 9}Be) source with activity 12Ci and neutron flux 10{sup 5} n. cm{sup −2}. s{sup −1}. The irradiation times -T{sub D} for detector were 4h, 8h, 16h and 24h. Chemical etching solution for detector was sodium hydroxide NaOH, 6.25N with 45 min etching time and 60 C° temperature. Images of CR-39 detector after chemical etching were taken from digital camera which connected from optical microscope. MATLAB software version 7.0 was used to image processing. The outputs of image processing of MATLAB software were analyzed and found the following relationships: (a) The irradiation time -T{sub D} has behavior linear relationships with following nuclear track parameters: i) total track number - N{sub T} ii) maximum track number - MRD (relative to track diameter - D{sub T}) at response region range 2.5 µm to 4 µm iii) maximum track number - M{sub D} (without depending on track diameter - D{sub T}). (b) The irradiation time -T{sub D} has behavior logarithmic relationship with maximum track number - M{sub A} (without depending on track area - A{sub T}). The image processing technique principally track diameter - D{sub T} can be take into account to classification of α-particle emitters, In addition to the contribution of these technique in preparation of nano- filters and nano-membrane in nanotechnology fields.

  15. Employment of single-diode model to elucidate the variations in photovoltaic parameters under different electrical and thermal conditions

    Science.gov (United States)

    Hameed, Shilan S.; Aziz, Fakhra; Sulaiman, Khaulah; Ahmad, Zubair

    2017-01-01

    In this research work, numerical simulations are performed to correlate the photovoltaic parameters with various internal and external factors influencing the performance of solar cells. Single-diode modeling approach is utilized for this purpose and theoretical investigations are compared with the reported experimental evidences for organic and inorganic solar cells at various electrical and thermal conditions. Electrical parameters include parasitic resistances (Rs and Rp) and ideality factor (n), while thermal parameters can be defined by the cells temperature (T). A comprehensive analysis concerning broad spectral variations in the short circuit current (Isc), open circuit voltage (Voc), fill factor (FF) and efficiency (η) is presented and discussed. It was generally concluded that there exists a good agreement between the simulated results and experimental findings. Nevertheless, the controversial consequence of temperature impact on the performance of organic solar cells necessitates the development of a complementary model which is capable of well simulating the temperature impact on these devices performance. PMID:28793325

  16. Parameter estimation of soil hydraulic and thermal property functions for unsaturated porous media using the HYDRUS-2D code

    Directory of Open Access Journals (Sweden)

    Nakhaei Mohammad

    2014-03-01

    Full Text Available Knowledge of soil hydraulic and thermal properties is essential for studies involving the combined effects of soil temperature and water input on water flow and redistribution processes under field conditions. The objective of this study was to estimate the parameters characterizing these properties from a transient water flow and heat transport field experiment. Real-time sensors built by the authors were used to monitor soil temperatures at depths of 40, 80, 120, and 160 cm during a 10-hour long ring infiltration experiment. Water temperatures and cumulative infiltration from a single infiltration ring were monitored simultaneously. The soil hydraulic parameters (the saturated water content θ s, empirical shape parameters α and n, and the saturated hydraulic conductivity Ks and soil thermal conductivity parameters (coefficients b1, b2, and b3 in the thermal conductivity function were estimated from cumulative infiltration and temperature measurements by inversely solving a two-dimensional water flow and heat transport using HYDRUS-2D. Three scenarios with a different, sequentially decreasing number of optimized parameters were considered. In scenario 1, seven parameters (θ s, Ks, α, n, b1, b2, and b3 were included in the inverse problem. The results indicated that this scenario does not provide a unique solution. In scenario 2, six parameters (Ks, α, n, b1, b2, and b3 were included in the inverse problem. The results showed that this scenario also results in a non-unique solution. Only scenario 3, in which five parameters (α, n, b1, b2, and b3 were included in the inverse problem, provided a unique solution. The simulated soil temperatures and cumulative infiltration during the ring infiltration experiment compared reasonably well with their corresponding observed values.

  17. A Co-modeling Method Based on Component Features for Mechatronic Devices in Aero-engines

    Science.gov (United States)

    Wang, Bin; Zhao, Haocen; Ye, Zhifeng

    2017-08-01

    Data-fused and user-friendly design of aero-engine accessories is required because of their structural complexity and stringent reliability. This paper gives an overview of a typical aero-engine control system and the development process of key mechatronic devices used. Several essential aspects of modeling and simulation in the process are investigated. Considering the limitations of a single theoretic model, feature-based co-modeling methodology is suggested to satisfy the design requirements and compensate for diversity of component sub-models for these devices. As an example, a stepper motor controlled Fuel Metering Unit (FMU) is modeled in view of the component physical features using two different software tools. An interface is suggested to integrate the single discipline models into the synthesized one. Performance simulation of this device using the co-model and parameter optimization for its key components are discussed. Comparison between delivery testing and the simulation shows that the co-model for the FMU has a high accuracy and the absolute superiority over a single model. Together with its compatible interface with the engine mathematical model, the feature-based co-modeling methodology is proven to be an effective technical measure in the development process of the device.

  18. COMPUTER-BASED ANALYSIS OF THERMAL TREATMENT PARAMETERS APPLICABLE TO MINERAL WOOL PRODUCTS

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2013-01-01

    Full Text Available Properties of mineral wool products are, to a significant extent, pre-set by conditions of their thermal treatment. The findings of analytical and experimental researches into patterns of thermal treatment of mineral wool carpets have been converted into dominant factors of influence used to compile a network of factor-to-factor dependencies and resulting characteristics. Dependencies derived in pursuance of the aforementioned pattern serve as the basis for the algorithm of software programmes integrated into a single software facility. The software facility is designated for the analysis of the value of hydraulic resistance of a mineral wool carpet exposed to thermal treatment using the method of heat carrier blowing through the mineral wool carpet layer spread over the punched surface of the transporter. The software facility may be used to identify the minimal length of the thermal treatment chamber and the thermal treatment exposure time.

  19. Benchmarking a new closed-form thermal analysis technique against a traditional lumped parameter, finite-difference method

    Energy Technology Data Exchange (ETDEWEB)

    Huff, K. D.; Bauer, T. H. (Nuclear Engineering Division)

    2012-08-20

    A benchmarking effort was conducted to determine the accuracy of a new analytic generic geology thermal repository model developed at LLNL relative to a more traditional, numerical, lumped parameter technique. The fast-running analytical thermal transport model assumes uniform thermal properties throughout a homogenous storage medium. Arrays of time-dependent heat sources are included geometrically as arrays of line segments and points. The solver uses a source-based linear superposition of closed form analytical functions from each contributing point or line to arrive at an estimate of the thermal evolution of a generic geologic repository. Temperature rise throughout the storage medium is computed as a linear superposition of temperature rises. It is modeled using the MathCAD mathematical engine and is parameterized to allow myriad gridded repository geometries and geologic characteristics [4]. It was anticipated that the accuracy and utility of the temperature field calculated with the LLNL analytical model would provide an accurate 'birds-eye' view in regions that are many tunnel radii away from actual storage units; i.e., at distances where tunnels and individual storage units could realistically be approximated as physical lines or points. However, geometrically explicit storage units, waste packages, tunnel walls and close-in rock are not included in the MathCAD model. The present benchmarking effort therefore focuses on the ability of the analytical model to accurately represent the close-in temperature field. Specifically, close-in temperatures computed with the LLNL MathCAD model were benchmarked against temperatures computed using geometrically-explicit lumped-parameter, repository thermal modeling technique developed over several years at ANL using the SINDAG thermal modeling code [5]. Application of this numerical modeling technique to underground storage of heat generating nuclear waste streams within the proposed YMR Site has been widely

  20. Influence of Annealing on the Optical Parameters of In2S3 Thin Films Produced by Thermal Evaporation

    Science.gov (United States)

    Izadneshan, H.; Gremenok, V. F.

    2014-05-01

    In2S3 thin fi lms are grown on glass substrates by vacuum thermal evaporation followed by annealing in vacuum between 330 and 400 °C for different time durations. We have investigated the infl uence of the annealing parameters on the characteristics of thin fi lms. It is shown that thermal treatment changed the crystal structure and optical energy band gap of In2S3 thin fi lms. Two energy band gaps were determined for all the fi lms, one indirect and the other direct.

  1. Design parameters of a non-air-conditioned cinema hall for thermal comfort under arid-zone climatic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Tiwari, G.N. (Indian Inst. of Tech., New Delhi (India). Centre for Energy Studies); Lugani, N. (Indian Inst. of Tech., New Delhi (India). Centre for Energy Studies); Singh, A.K. (Indian Inst. of Tech., New Delhi (India). Centre for Energy Studies)

    1993-01-01

    In this communication, a design of a cinema hall suitable for climatic conditions in an arid zone has been presented. The various cooling techniques, namely evaporative cooling, wind tower, ventilation/infiltration and natural cooling, have been incorporated in the design to achieve thermal comfort during the period of operation. The design parameters have been optimized on the basis of numerical computations after establishing an energy balance for each component of a cinema hall. It is observed that cooling treatment, i.e., a wind tower with a cooling pool on the roof provides reasonable thermal comfort inside the enclosure. (orig.)

  2. Exploring the relationship between structurally defined geometrical parameters of reinforced concrete beams and the thermal comfort on indoor environment

    DEFF Research Database (Denmark)

    Lee, Daniel Sang-Hoon; Naboni, Emanuele

    2017-01-01

    with light, sound and thermal conditions. It is considered that the characteristics of interferences would have close relationship with material and geometrical properties of the soffits; especially when the soffits are other than flat form. In the current investigation the relationship between the thermal......-sectioned beams. However, both flange and web are curved vertically for the required bending and shear capacity of the sections. At the same time, the web is also curved horizontally for increased shear capacities. In the research, both the vertical and horizontal geometrical parameters are varied to observe...

  3. Filtered Rayleigh scattering diagnostic for multi-parameter thermal-fluids measurements : LDRD final report.

    Energy Technology Data Exchange (ETDEWEB)

    Beresh, Steven Jay; Grasser, Thomas W.; Kearney, Sean Patrick; Schefer, Robert W.

    2004-01-01

    Simulation-based life-cycle-engineering and the ASCI program have resulted in models of unprecedented size and fidelity. The validation of these models requires high-resolution, multi-parameter diagnostics. Within the thermal-fluids disciplines, the need for detailed, high-fidelity measurements exceeds the limits of current engineering sciences capabilities and severely tests the state of the art. The focus of this LDRD is the development and application of filtered Rayleigh scattering (FRS) for high-resolution, nonintrusive measurement of gas-phase velocity and temperature. With FRS, the flow is laser-illuminated and Rayleigh scattering from naturally occurring sources is detected through a molecular filter. The filtered transmission may be interpreted to yield point or planar measurements of three-component velocities and/or thermodynamic state. Different experimental configurations may be employed to obtain compromises between spatial resolution, time resolution, and the quantity of simultaneously measured flow variables. In this report, we present the results of a three-year LDRD-funded effort to develop FRS combustion thermometry and Aerosciences velocity measurement systems. The working principles and details of our FRS opto-electronic system are presented in detail. For combustion thermometry we present 2-D, spatially correlated FRS results from nonsooting premixed and diffusion flames and from a sooting premixed flame. The FRS-measured temperatures are accurate to within {+-}50 K (3%) in a premixed CH4-air flame and within {+-}100 K for a vortex-strained diluted CH4-air diffusion flame where the FRS technique is severely tested by large variation in scattering cross section. In the diffusion flame work, FRS has been combined with Raman imaging of the CH4 fuel molecule to correct for the local light scattering properties of the combustion gases. To our knowledge, this is the first extension of FRS to nonpremixed combustion and the first use of joint FRS

  4. Determination of physiological parameters and thermal gradients of Anglo-nubian goatling in Brazilian semiarid

    Directory of Open Access Journals (Sweden)

    Alessandra de Sousa Alves

    2014-07-01

    Full Text Available The aim of this study was to evaluate the thermal gradients of Anglo nubian goatling fed artificially and maintained under the same environmental conditions in semiarid. Were used 22 goatling aged 90 days and in this experiment a completely randomized design was used. The rectal temperature, respiratory rate and the surface temperature of the animals were measured. The thermal characterization of the environment was realized, through the Black Globe Temperature Humidity Index. The thermal gradients were evaluated by the difference between the rectal temperature and surface temperature (TRTS and the difference between the surface temperature and the ambient temperature (TSTA. The values found for the Black Globe Temperature Humidity Index were 79.37 °C and for the thermal gradients were 3.6 °C and 5.3 °C for TRTS and TSTA respectively. The Anglo-nubian goatling showed good adaptability to semi-arid region.

  5. Coupling urbanization analyses for studying urban thermal environment and its interplay with biophysical parameters based on TM/ETM+ imagery

    Science.gov (United States)

    Ma, Ya; Kuang, Yaoqiu; Huang, Ningsheng

    2010-04-01

    Studies of urbanization and urban thermal environment are now attracting wide interests among scientists all over the world. This study investigated the influences of urbanization on urban thermal environment as well as the relationships of thermal characteristics to other biophysical variables in Guangzhou, China utilizing three dates of Landsat TM/ETM+ images acquired in 1990, 2000, and 2005, respectively. Vegetation abundances and percent impervious surfaces were derived by means of linear spectral mixture model, and a method for effectively enhancing impervious surface has been developed to accurately examine the urban enlargement. As a key parameter for studying urban thermal characteristics, the land surface temperature (LST) was also retrieved from thermal infrared band of each TM/ETM+ dataset. Based on these parameters, the urban expansion, urban heat island effect and the relationships of LSTs to other biophysical parameters were then analyzed. Results indicated that the area ratio of impervious surface in Guangzhou increased significantly, which grew from 20.56% in 1990, to 34.72% in 2000, and further to 41.12% in 2005, however, the intensity of urban heat island was not always enlarged in observed years. In addition, Geostatistical analyses showed that the mean-centre of the impervious surface was moving towards the northwest during 1990-2005. And correlation analyses revealed that, at the pixel-scale, the association of LSTs to other two variables (vegetation abundance and percent impervious surface) was not straightforward, while LSTs possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional-scale, respectively. This study provided an integrated research scheme and the findings can be very useful for urban ecosystem modeling.

  6. Measurements of some parameters of thermal sparks with respect to their ability to ignite aviation fuel/air mixtures

    Science.gov (United States)

    Haigh, S. J.; Hardwick, C. J.; Baldwin, R. E.

    1991-01-01

    A method used to generate thermal sparks for experimental purposes and methods by which parameters of the sparks, such as speed, size, and temperature, were measured are described. Values are given of the range of such parameters within these spark showers. Titanium sparks were used almost exclusively, since it is particles of this metal which are found to be ejected during simulation tests to carbon fiber composite (CFC) joints. Tests were then carried out in which titanium sparks and spark showers were injected into JP4/(AVTAG F40) mixtures with air. Single large sparks and dense showers of small sparks were found to be capable of causing ignition. Tests were then repeated using ethylene/air mixtures, which were found to be more easily ignited by thermal sparks than the JP4/ air mixtures.

  7. Global dust model intercomparison in AeroCom phase I

    Directory of Open Access Journals (Sweden)

    N. Huneeus

    2011-08-01

    Full Text Available This study presents the results of a broad intercomparison of a total of 15 global aerosol models within the AeroCom project. Each model is compared to observations related to desert dust aerosols, their direct radiative effect, and their impact on the biogeochemical cycle, i.e., aerosol optical depth (AOD and dust deposition. Additional comparisons to Angström exponent (AE, coarse mode AOD and dust surface concentrations are included to extend the assessment of model performance and to identify common biases present in models. These data comprise a benchmark dataset that is proposed for model inspection and future dust model development. There are large differences among the global models that simulate the dust cycle and its impact on climate. In general, models simulate the climatology of vertically integrated parameters (AOD and AE within a factor of two whereas the total deposition and surface concentration are reproduced within a factor of 10. In addition, smaller mean normalized bias and root mean square errors are obtained for the climatology of AOD and AE than for total deposition and surface concentration. Characteristics of the datasets used and their uncertainties may influence these differences. Large uncertainties still exist with respect to the deposition fluxes in the southern oceans. Further measurements and model studies are necessary to assess the general model performance to reproduce dust deposition in ocean regions sensible to iron contributions. Models overestimate the wet deposition in regions dominated by dry deposition. They generally simulate more realistic surface concentration at stations downwind of the main sources than at remote ones. Most models simulate the gradient in AOD and AE between the different dusty regions. However the seasonality and magnitude of both variables is better simulated at African stations than Middle East ones. The models simulate the offshore transport of West Africa throughout the year

  8. Estimation of the kinetic parameters for thermal decomposition of HNIW and its adiabatic time-to-explosion by Kooij formula

    Institute of Scientific and Technical Information of China (English)

    Hong-xu GAO; Feng-qi ZHAO; Rong-zu HU; Hong-an ZHAO; Hai ZHANG

    2014-01-01

    A differential/integral method to estimate the kinetic parameters (apparent activation energy Ea and pre-exponential factor A) for thermal decomposition reaction of energetic materials based on Kooij formula are applied to study the nonisothermal decomposition reaction kinetics of hexanitrohexaazaisowurtzitane (HNIW) by analyzing nonisothermal DSC curve data. The apparent activation energy (Ea) obtained by the in-tegral isoconversional non-isothermal method based on Kooij formula is used to check the constancy and validity of apparent activation energy by the differential/integral method based on Kooij formula. The most probable mechanism function of thermal decomposition reaction of HNIW is determined by a logical choice method. The equations for calculating the critical temperatures of thermal explosion (Tb) and adiabatic time-to-explosion (tTIad) based on Kooij formula are used to calculate the values of Tb and tTIad to evaluate the thermal safety and heat-resistant ability of HNIW. All the original data needed for analyzing the kinetic parameters are from nonisothermal DSC curves. The results show that the kinetic model function in differential form and the values of Ea and A of decomposition reaction of HNIW are 3(1 ? a)[?ln(1 ? a)]2/3, 152.73 kJ mol?1 and 1011.97 s?1, respectively, and the values of self-accelerating decomposition temperature (TSADT), Tb and tTIad are 486.55 K, 493.11 K and 52.01 s, respectively.

  9. Generalized Grüneisen parameters and low temperature limit of lattice thermal expansion of cadmium and zirconium

    Indian Academy of Sciences (India)

    S Sindhu; C S Menon

    2006-09-01

    The generalized Grüneisen parameters ($_{j}^{'}$) and ($_{j}^{''}$) for cadmium and zirconium were calculated from the second- and third-order elastic constants to determine the low temperature limit of the volume thermal expansion of these metals of hexagonal symmetry. The low temperature limit of cadmium and zirconium was calculated to be positive values indicating a positive volume expansion down to 0 K even though many Grüneisen gammas were found to be negative.

  10. MAINTENANCE LEVEL DECISION OF AERO-ENGINE BASED ON VPRS THEORY%基于VPRS理论的航空发动机送修等级决策

    Institute of Scientific and Technical Information of China (English)

    张海军; 左洪福; 梁剑

    2005-01-01

    An aero-engine is a typically repairable and complex system and its maintenance level has a close relationship with the maintenance cost. The inaccurate measurement for the maintenance level of an aero-engine can induce higher overhaul maintenance costs. Variable precision rough set (VPRS) theory is used to determine the maintenance level of an aero-engine. According to the relationship between condition information and performance parameters of aero-engine modules, decision rules are established for reflecting the real condition of an aeroengine when its maintenance level needs to be determined. Finally, the CF6 engine is used as an example to illustrate the method to be effective.%应用变精度粗糙集理论研究了发动机状态信息与单元体性能参数之间的关系,提出了一种基于信息熵属性约简的航空公司发动机维修等级决策方法,从而在维修决策时能够更加客观地反映发动机实际损伤程度.最后以CF6型发动机维修等级决策规则生成为例说明了该决策方法的有效性.

  11. APPLICATION OF ROUGH SET THEORY TO MAINTENANCE LEVEL DECISION-MAKING FOR AERO-ENGINE MODULES BASED ON INCREMENTAL KNOWLEDGE LEARNING

    Institute of Scientific and Technical Information of China (English)

    陆晓华; 左洪福; 蔡景

    2013-01-01

    The maintenance of an aero-engine usually includes three levels ,and the maintenance cost and period greatly differ depending on the different maintenance levels .To plan a reasonable maintenance budget program , airlines would like to predict the maintenance level of aero-engine before repairing in terms of performance parame-ters ,which can provide more economic benefits .The maintenance level decision rules are mined using the histori-cal maintenance data of a civil aero-engine based on the rough set theory ,and a variety of possible models of upda-ting rules produced by newly increased maintenance cases added to the historical maintenance case database are in-vestigated by the means of incremental machine learning .The continuously updated rules can provide reasonable guidance suggestions for engineers and decision support for planning a maintenance budget program before repai-ring .The results of an example show that the decision rules become more typical and robust ,and they are more accurate to predict the maintenance level of an aero-engine module as the maintenance data increase ,which illus-trates the feasibility of the represented method .

  12. XCOR AeroSpace: Providing Low Cost Access to Space

    Science.gov (United States)

    2009-02-01

    transport anywhere in world and fly (6-8000 ft of runway needed) • Fly unpredictable times, multiple times per day, cheaply! • Small Satellite Launch...programs • Avoiding ONE failure or substantial program slip pays for the whole Lynx program many -fold UPDATE - Progress In Last 30 Days 7 •Further...troops released from delivery system – TPS built in to suits or MOOSE -like solo system – Aero deceleration high in atmosphere, GPS-guided chutes

  13. Net-Shape Processing Applied to Aero-Engine Components

    Science.gov (United States)

    2006-05-01

    sustainable in the aero-engine business as the cost of key materials such as titanium and nickel alloys is escalating, fuelled by the seemingly...have deformed to consolidate the powder is removed by rough machining and/or pickling to reveal the net-shape component. The key to producing net...being relatively expensive in terms of cost and environmental impact, mainly due to the cost of machining the mild steel tooling and having to pickle

  14. Air Force Research in Aero Propulsion Technology (AFRAPT)

    Science.gov (United States)

    1990-09-27

    Aero Propulsion Technology (AFRAPT) 12. PERSONAL AUTHOR(S) Profs. J. Dugundji , A. Epstein, M. Giles, E. Greitzer, M. Martinez-Sanchez, flr r T~ri 13a...Professor of Aeronautics and Astronautics Director, Gas Turbine Laboratory John Dugundji Professor, Dept. of Aeronautics and Astronautics Alan H. Epstein...Professor J. Dugundji /Professor E.M. Greitzer Project: Compressor Stabilization Through Structural Feedback Trainee: Dana Lindquist Advisor: Professor M.B

  15. Thermal modeling environment for TMT

    OpenAIRE

    Vogiatzis, Konstantinos

    2010-01-01

    In a previous study we had presented a summary of the TMT Aero-Thermal modeling effort to support thermal seeing and dynamic loading estimates. In this paper a summary of the current status of Computational Fluid Dynamics (CFD) simulations for TMT is presented, with the focus shifted in particular towards the synergy between CFD and the TMT Finite Element Analysis (FEA) structural and optical models, so that the thermal and consequent optical deformations of the telescope can be calculated. T...

  16. Functional parameters of radio-electronic system stipulated by thermal processes in it

    Directory of Open Access Journals (Sweden)

    Yu. F. Zinkovskiy

    2014-09-01

    Full Text Available Statement of the problem. The features of thermal processes in the structural modules of radio-electronic apparatus -сells and microassemblies, elements of their electronic structure are reviewed. Internal thermal processes. The internal thermal processes in elements of electronic structure are considered. Efficiency factor of modules, energy efficiency indicators of resistors, capacitors, inductances based on models of equivalent two-terminalare analyzed. The basic structural elements of radioelectronic devices. The design feature of cells and mikroassemblies are considered. Thermal field of a cell and microassembly. The basic mathematical models to determine the temperatures of the elements of cells and microassemblies electronic structure are proposed. Thermal field of microassemblies is modeled, analytical equation for determin ing the temperature of all its elements is obtained. Account of temperatures of microassembly. The results of imitating modeling of temperatures microassemblies with various conditions of cooling are submitted. Software definition of temperatures for cells and microassemblies. The automated designing programs for the temperature modes account in cells and microassembly of the radio-electronic are described. Conclusions. The primary tasks performed in the work are listed.

  17. Experimental Study on Aero Conductivity of Porous Media

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    To study the variation pattern of aero conductivity of different porous media under low pressure conditions, three kinds of media are selected.These include sandy clay loam, fine sand, and medium sand, and air as fluid to conduct soil column ventilation tests.Pressure at both ends of the columns is measured under different ventilation flow rates during testing.The test results show that the aero conductivity, solved by Darcy's law, is not a constant.It is a variable, which increases first when air flow velocity is less than 0.258 7 cm/ s for sandy clay loam, 0.637 3 cm/s for fine sand and then decreases when air flow velocity is bigger than that with the increase of the ventilation flow rate when the medium is determined.By analyzing various factors that influence the flow resistance, the reasons for variation in aero conductivity are found as follows: first, the change of pore structure results in better ventilation; second, the relationship between pressure head loss and air flow velocity is nonlinear, and it is beyond the condition of the laminar flow domain to which Darcy's law can be applied, when the air flow rate increases to a certain value and the flow velocity is in the transition range to turbulent flow.

  18. Failure Analysis towards Reliable Performance of Aero-Engines

    Directory of Open Access Journals (Sweden)

    T. Jayakumar

    1999-10-01

    Full Text Available Aero-engines are critical components whose reliable performance decides the primary safety of anaircrafthelicopter. This is met by rigorous maintenance schedule with periodic inspection/nondestructive testingof various engine components. In spite of these measures, failure of areo-engines do occur rather frequentlyin comparison to failure of other components. Systematic failure analysis helps one to identify root causeof the failure, thus enabling remedial measures to prevent recurrence of such failures. Turbine blades madeof nickel or cobalt-based alloys are used in aero-engines. These blades are subjected to complex loadingconditions at elevated temperatures. The main causes of failure of blades are attributed to creep, thermalfatigue and hot corrosion. Premature failure of blades in the combustion zone was reported in one of theaero-engines. The engine had both the compressor and the free-turbine in a common shaft. Detailedfailure analysis revealed the presence of creep voids in the blades that failed. Failure of turbine bladeswas also detected in another aero-engine operating in a coastal environment. In this failure, the protectivecoating on the blades was cracked at many locations. Grain boundary spikes were observed on these locations.The primary cause of this failure was the hot corrosion followed by creep damage

  19. Improved methods for measuring thermal parameters of liquid samples using photothermal infrared radiometry

    Science.gov (United States)

    Kuriakose, Maju; Depriester, Michael; Dadarlat, Dorin; Sahraoui, Abdelhak Hadj

    2013-02-01

    High accuracy, non-contact measuring methods for finding thermal properties of liquid samples using photothermal infrared radiometry (PTR) are presented. The use of transparent windows to confine micro volume liquid samples and the implementation of front and/or back signal detection procedures helped the successful implementation of the PTR technique for measuring liquids with high proficiency. We present two configurations, the so-called back-front photothermal infrared radiometry and back photothermal infrared radiometry to find thermal diffusivity and thermal effusivity of liquid samples. Sensitivity studies and error analyses included prove the robustness of each method. As an illustration of the temperature and electric field varying studies, we have included the experimental results on a 5CB (4-cyano-4‧-pentylbiphenyl) liquid crystal.

  20. Increasing the Performance and Reliability of Power Boiler by Monitoring Thermal and Strength Parameters

    OpenAIRE

    Sobota Tomasz

    2017-01-01

    The paper presents a method for determination of thermo-flow parameters for steam boilers. This method allows to perform the calculations of the boiler furnace chamber and heat flow rates absorbed by superheater stages. These parameters are important for monitoring the performance of the power unit. Knowledge of these parameters allows determining the degree of the furnace chamber slagging. The calculation can be performed in online mode and use to monitoring of steam boiler. The presented me...

  1. The thermal properties of the subsurface – key parameters for geothermal energy utilization

    DEFF Research Database (Denmark)

    Norden, Ben; Bording, Thue Sylvester; Balling, N.

    Often the investigation of petrophysical properties is far behind the capabilities of sophisticated modelling techniques applied in basin and geothermal modelling and for which these data serve as an input. Therefore, more in-depth investigations especially of thermal properties are requested. We...

  2. Thermal hydrocracking of indan. Effects of the hydrogen pressure on the kinetics and Arrhenius parameters

    NARCIS (Netherlands)

    Boven, van M.; Roskam, G.J.; Penninger, J.M.L.

    1975-01-01

    The kinetics of the thermal hydrocracking of indan were investigatedin a high-pressure flow reactor at temperatures from 470 to 530°C, total pressures of up to 300 atm, and molar ratios from 3 to 40. The effect of the hydrogen pressure was reflected especially in a change of the experimental rate eq

  3. Thermal comfort in residential buildings: Sensitivity to building parameters and occupancy

    NARCIS (Netherlands)

    Ioannou, A.; Itard, L.C.M.

    2014-01-01

    Dynamic simulation is widely used for assessing thermal comfort in dwellings. Simulation tools, though, have shortcomings due to false assumptions made during the design phase of buildings, limited information on the building's envelope and installations and misunderstandings over the role of the oc

  4. The thermal properties of the subsurface – key parameters for geothermal energy utilization

    DEFF Research Database (Denmark)

    Norden, Ben; Bording, Thue Sylvester; Balling, N.

    Often the investigation of petrophysical properties is far behind the capabilities of sophisticated modelling techniques applied in basin and geothermal modelling and for which these data serve as an input. Therefore, more in-depth investigations especially of thermal properties are requested. We...

  5. A systematic approach to determine global thermal inactivation parameters for various food pathogens

    NARCIS (Netherlands)

    Asselt, van E.D.; Zwietering, M.H.

    2006-01-01

    Thermal inactivation of pathogens has been studied extensively, which has resulted in a wide range of D- and z-values. Estimating the inactivation rate for a specific condition based on these reported values is difficult, since one has to select representative conditions, and data obtained exactly a

  6. Influence of soil moisture content on surface albedo and soil thermal parameters at a tropical station

    Science.gov (United States)

    Sugathan, Neena; Biju, V.; Renuka, G.

    2014-06-01

    Half hourly data of soil moisture content, soil temperature, solar irradiance, and reflectance are measured during April 2010 to March 2011 at a tropical station, viz., Astronomical Observatory, Thiruvananthapuram, Kerala, India (76°59'E longitude and 8°29'N latitude). The monthly, seasonal and seasonal mean diurnal variation of soil moisture content is analyzed in detail and is correlated with the rainfall measured at the same site during the period of study. The large variability in the soil moisture content is attributed to the rainfall during all the seasons and also to the evaporation/movement of water to deeper layers. The relationship of surface albedo on soil moisture content on different time scales are studied and the influence of solar elevation angle and cloud cover are also investigated. Surface albedo is found to fall exponentially with increase in soil moisture content. Soil thermal diffusivity and soil thermal conductivity are also estimated from the subsoil temperature profile. Log normal dependence of thermal diffusivity and power law dependence of thermal conductivity on soil moisture content are confirmed.

  7. Influence of soil moisture content on surface albedo and soil thermal parameters at a tropical station

    Indian Academy of Sciences (India)

    Neena Sugathan; V Biju; G Renuka

    2014-07-01

    Half hourly data of soil moisture content, soil temperature, solar irradiance, and reflectance are measured during April 2010 to March 2011 at a tropical station, viz., Astronomical Observatory, Thiruvananthapuram, Kerala, India (76° 59’E longitude and 8°29’N latitude). The monthly, seasonal and seasonal mean diurnal variation of soil moisture content is analyzed in detail and is correlated with the rainfall measured at the same site during the period of study. The large variability in the soil moisture content is attributed to the rainfall during all the seasons and also to the evaporation/movement of water to deeper layers. The relationship of surface albedo on soil moisture content on different time scales are studied and the influence of solar elevation angle and cloud cover are also investigated. Surface albedo is found to fall exponentially with increase in soil moisture content. Soil thermal diffusivity and soil thermal conductivity are also estimated from the subsoil temperature profile. Log normal dependence of thermal diffusivity and power law dependence of thermal conductivity on soil moisture content are confirmed.

  8. Thermal hydrocracking of indan. Effects of the hydrogen pressure on the kinetics and Arrhenius parameters

    NARCIS (Netherlands)

    van Boven, M.; Roskam, G.J.; Penninger, J.M.L.

    1975-01-01

    The kinetics of the thermal hydrocracking of indan were investigatedin a high-pressure flow reactor at temperatures from 470 to 530°C, total pressures of up to 300 atm, and molar ratios from 3 to 40. The effect of the hydrogen pressure was reflected especially in a change of the experimental rate

  9. Thermal effect on magnetic parameters of high-coercivity cobalt ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Chagas, E. F., E-mail: efchagas@fisica.ufmt.br; Ponce, A. S.; Prado, R. J.; Silva, G. M. [Instituto de Física, Universidade Federal de Mato Grosso, 78060-900 Cuiabá-MT (Brazil); Bettini, J. [Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais, 13083-970 Campinas (Brazil); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150 Urca. Rio de Janeiro (Brazil)

    2014-07-21

    We prepared very high-coercivity cobalt ferrite nanoparticles synthesized by a combustion method and using short-time high-energy mechanical milling to increase strain and the structural defects density. The coercivity (H{sub C}) of the milled sample reached 3.75 kOe—a value almost five times higher than that obtained for the non-milled material (0.76 kOe). To investigate the effect of the temperature on the magnetic behavior of the milled sample, we performed a thermal treatment on the milled sample at 300, 400, and 600 °C for 30 and 180 min. We analyzed the changes in the magnetic behavior of the nanoparticles due to the thermal treatment using the hysteresis curves, Williamson-Hall analysis, and transmission electron microscopy. The thermal treatment at 600 °C causes decreases in the microstructural strain and density of structural defects resulting in a significant decrease in H{sub C}. Furthermore, this thermal treatment increases the size of the nanoparticles and, as a consequence, there is a substantial increase in the saturation magnetization (M{sub S}). The H{sub C} of the samples treated at 600 °C for 30 and 180 min were 2.24 and 1.93 kOe, respectively, and the M{sub S} of these same samples increased from 57 emu/g to 66 and 70 emu/g, respectively. The H{sub C} and the M{sub S} are less affected by the thermal treatment at 300 and 400 °C.

  10. Increasing the Performance and Reliability of Power Boiler by Monitoring Thermal and Strength Parameters

    Directory of Open Access Journals (Sweden)

    Sobota Tomasz

    2017-01-01

    Full Text Available The paper presents a method for determination of thermo-flow parameters for steam boilers. This method allows to perform the calculations of the boiler furnace chamber and heat flow rates absorbed by superheater stages. These parameters are important for monitoring the performance of the power unit. Knowledge of these parameters allows determining the degree of the furnace chamber slagging. The calculation can be performed in online mode and use to monitoring of steam boiler. The presented method allows to the operation of steam boiler with high efficiency.

  11. Thermophysical parameters of coconut oil and its potential application as the thermal energy storage system in Indonesia

    Science.gov (United States)

    Putri, Widya A.; Fahmi, Zulfikar; Sutjahja, I. M.; Kurnia, D.; Wonorahardjo, S.

    2016-08-01

    The high consumption of electric energy for room air conditioning (AC) system in Indonesia has driven the research of potential thermal energy storage system as a passive temperature controller. The application of coconut oil (CO) as the potential candidate for this purpose has been motivated since its working temperature just around the human thermal comfort zone in the tropical area as Indonesia. In this research we report the time-dependent temperature data of CO, which is adopting the T-history method. The analysis of the data revealed a set of thermophysical parameters, consist of the mean specific heats of the solid and liquid, as well as the latent heat of fusion for the phase change transition. The performance of CO to decrease the air temperature was measured in the thermal chamber. From the results it is shown that the latent phase of CO related to the solid-liquid phase transition show the highest capability in heat absorption, directly showing the potential application of CO as thermal energy storage system in Indonesia.

  12. Optimization of Indoor Thermal Comfort Parameters with the Adaptive Network-Based Fuzzy Inference System and Particle Swarm Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Jing Li

    2017-01-01

    Full Text Available The goal of this study is to improve thermal comfort and indoor air quality with the adaptive network-based fuzzy inference system (ANFIS model and improved particle swarm optimization (PSO algorithm. A method to optimize air conditioning parameters and installation distance is proposed. The methodology is demonstrated through a prototype case, which corresponds to a typical laboratory in colleges and universities. A laboratory model is established, and simulated flow field information is obtained with the CFD software. Subsequently, the ANFIS model is employed instead of the CFD model to predict indoor flow parameters, and the CFD database is utilized to train ANN input-output “metamodels” for the subsequent optimization. With the improved PSO algorithm and the stratified sequence method, the objective functions are optimized. The functions comprise PMV, PPD, and mean age of air. The optimal installation distance is determined with the hemisphere model. Results show that most of the staff obtain a satisfactory degree of thermal comfort and that the proposed method can significantly reduce the cost of building an experimental device. The proposed methodology can be used to determine appropriate air supply parameters and air conditioner installation position for a pleasant and healthy indoor environment.

  13. Estimation of the kinetic parameters for thermal decomposition of HNIW and its adiabatic time-to-explosion by Kooij formula

    Directory of Open Access Journals (Sweden)

    Hong-xu Gao

    2014-03-01

    Full Text Available A differential/integral method to estimate the kinetic parameters (apparent activation energy Ea and pre-exponential factor A for thermal decomposition reaction of energetic materials based on Kooij formula are applied to study the nonisothermal decomposition reaction kinetics of hexanitrohexaazaisowurtzitane (HNIW by analyzing nonisothermal DSC curve data. The apparent activation energy (Ea obtained by the integral isoconversional non-isothermal method based on Kooij formula is used to check the constancy and validity of apparent activation energy by the differential/integral method based on Kooij formula. The most probable mechanism function of thermal decomposition reaction of HNIW is determined by a logical choice method. The equations for calculating the critical temperatures of thermal explosion (Tb and adiabatic time-to-explosion (tTIad based on Kooij formula are used to calculate the values of Tb and tTIad to evaluate the thermal safety and heat-resistant ability of HNIW. All the original data needed for analyzing the kinetic parameters are from nonisothermal DSC curves. The results show that the kinetic model function in differential form and the values of Ea and A of decomposition reaction of HNIW are 3(1 − α[−ln(1 − α]2/3, 152.73 kJ mol−1 and 1011.97 s−1, respectively, and the values of self-accelerating decomposition temperature (TSADT, Tb and tTIad are 486.55 K, 493.11 K and 52.01 s, respectively.

  14. Research on optimal process parameters in thermally oxidation-assisted polishing of reaction-sintered silicon carbide

    Science.gov (United States)

    Shen, Xinmin; Yamamura, Kazuya; Zhang, Xiaonan; Zhang, Xiangpo; Wang, Dong; Peng, Kang

    2016-10-01

    Reaction-sintered silicon carbide (RS-SiC) has been widely used in space telescope systems for its excellent physical and mechanical properties. Thermally oxidation-assisted polishing is a practical machining method to obtain RS-SiC parts with high precision, and the research focus is optimization of process parameters, because there are bumpy structures on the oxidized RS-SiC. By atomic force microscopy (AFM) detection, the distributions of oxides on the oxidized RS-SiC sample are quantitative analyzed when the thermal oxidation time is 5min, 30min, and 60min, and the calculated average differences of oxide heights between the initial Si grains and SiC grains are 10.7nm, 25.1nm, and 35.2nm, respectively. Meanwhile, the volume expansion coefficient in oxidation of Si/SiC to SiO2 is 2.257 and 2.194, respectively. Through theoretical derivation based on the Deal-Grove model, the numerical relationship between differences of oxide heights and thermal oxidation time is obtained. Combining with the material removal rate of oxide by ceria slurry in the abrasive polishing, the obtained surface quality can be precisely forecasted and controlled. The oxidized RS-SiC sample, when the oxidation time is 30min, is polished with different times to verify the theoretical analysis results. When the polishing times are 20min, 30min, and 40min, the obtained differences of oxide heights by the AFM detection are consistent with theoretical calculated results. Research on the optimal process parameters in thermally oxidation-assisted polishing of RS-SiC can improve the process level of RS-SiC sample and promote the application of SiC parts.

  15. Estimation on the influence of uncertain parameters on stochastic thermal regime of embankment in permafrost regions

    Science.gov (United States)

    Wang, Tao; Zhou, Guoqing; Wang, Jianzhou; Zhao, Xiaodong; Chen, Xing

    2016-07-01

    For embankments in permafrost regions, the soil properties and the upper boundary conditions are stochastic because of complex geological processes and changeable atmospheric environment. These stochastic parameters lead to the fact that conventional deterministic temperature field of embankment become stochastic. In order to estimate the influence of stochastic parameters on random temperature field for embankment in permafrost regions, a series of simulated tests are conducted in this study. We consider the soil properties as random fields and the upper boundary conditions as stochastic processes. Taking the variability of each stochastic parameter into account individually or concurrently, the corresponding random temperature fields are investigated by Neumann stochastic finite element method. The results show that both of the standard deviation under the embankment and the boundary increase with time when considering the stochastic effect of soil properties and boundary conditions. Stochastic boundary conditions and soil properties play a different role in random temperature field of embankment at different times. Each stochastic parameter has a different effect on random temperature field. These results can improve our understanding of the influence of stochastic parameters on random temperature field for embankment in permafrost regions.

  16. Estimation on the influence of uncertain parameters on stochastic thermal regime of embankment in permafrost regions

    Science.gov (United States)

    Wang, Tao; Zhou, Guoqing; Wang, Jianzhou; Zhao, Xiaodong; Chen, Xing

    2017-03-01

    For embankments in permafrost regions, the soil properties and the upper boundary conditions are stochastic because of complex geological processes and changeable atmospheric environment. These stochastic parameters lead to the fact that conventional deterministic temperature field of embankment become stochastic. In order to estimate the influence of stochastic parameters on random temperature field for embankment in permafrost regions, a series of simulated tests are conducted in this study. We consider the soil properties as random fields and the upper boundary conditions as stochastic processes. Taking the variability of each stochastic parameter into account individually or concurrently, the corresponding random temperature fields are investigated by Neumann stochastic finite element method. The results show that both of the standard deviation under the embankment and the boundary increase with time when considering the stochastic effect of soil properties and boundary conditions. Stochastic boundary conditions and soil properties play a different role in random temperature field of embankment at different times. Each stochastic parameter has a different effect on random temperature field. These results can improve our understanding of the influence of stochastic parameters on random temperature field for embankment in permafrost regions.

  17. Effect of training level and blood flow restriction on thermal parameters: Preliminary study

    Science.gov (United States)

    Sampaio, Lucas; Bezerra, Ewertton; Paladino, Kayo; dos Santos, João Otacílio Libardoni; Priego Quesada, Jose I.; Rossato, Mateus

    2016-11-01

    Training with blood flow restriction could lead to an effect on skin temperature. Additionally, this effect could be higher in people with lower physical fitness level due to their lower capacity of heat loss. The aim of this preliminary study was therefore to evaluate the effects of training experience on the acute and chronic thermal skin responses after performing exercise with and without blood flow restriction. The study included ten men, of these, five were trained. All subjects performed tests and re-tests for maximum strength (1 repetition maximum) through unilateral leg extensions (right thigh at 45 ± 6.7 kg and left thigh at 45.5 ± 8.1 kg, p > 0.05). The protocol consisted of four sets to concentric failure, with one-minute rest intervals between sets at an intensity corresponding to 40% of 1 RM. There were 7-day intervals between experimental sessions (150 mmHg versus unrestricted flow restriction). The thermal images were made before the protocol (pre), immediately after the end of the series (post), and 24 h afterward (post 24 h). When comparing temperature variation (Δ exercise and Δ 24 h) between groups, it was observed that the trained participants showed a greater drop in temperature 24 h after exercise with 150 mmHg restriction (confidence interval: 95% of Δ 24 h [-0.2 to -0.9 °C]) compared to untrained subjects (p = 0.006 and ES > 1.5, confidence interval: 95% Δ 24 h [-0.1 to 0.6 °C].) In conclusion, this preliminary study showed that training experience interferes with the chronic cutaneous thermal temperature of the anterior thigh when strength training associated with blood flow restriction 150 mmHg was performed.

  18. Estimation of fracture parameters in foam core materials using thermal techniques

    DEFF Research Database (Denmark)

    Dulieu-Barton, J. M.; Berggreen, Christian; Boyenval Langlois, C.

    2010-01-01

    The paper presents some initial work on establishing the stress state at a crack tip in PVC foam material using a non-contact infra-red technique known as thermoelastic stress analysis (TSA). A parametric study of the factors that may affect the thermoelastic response of the foam material...... is described. A mode I simulated crack in the form of a machined notch is used to establish the feasibility of the TSA approach to derive stress intensity factors for the foam material. The overall goal is to demonstrate that thermal techniques have the ability to provide deeper insight into the behaviour...

  19. Distributed parameter modeling and thermal analysis of a spiral water wall in a supercritical boiler

    Directory of Open Access Journals (Sweden)

    Zheng Shu

    2013-01-01

    Full Text Available In this paper, a distributed parameter model for the evaporation system of a supercritical spiral water wall boiler is developed based on a 3-D temperature field. The mathematical method is formulated for predicting the heat flux and the metal-surface temperature. The results show that the influence of the heat flux distribution is more obvious than that of the heat transfer coefficient distribution in the spiral water wall tube, and the peak of the heat transfer coefficient decreases with an increment of supercritical pressure. This distributed parameter model can be used for a 600 MW supercritical-pressure power plant.

  20. CFD predictions of LBO limits for aero-engine combustors using fuel iterative approximation

    Institute of Scientific and Technical Information of China (English)

    Hu Bin; Huang Yong; Wang Fang; Xie Fa

    2013-01-01

    Lean blow-out (LBO) is critical to operational performance of combustion systems in propulsion and power generation.Current predictive tools for LBO limits are based on decadesold empirical correlations that have limited applicability for modern combustor designs.According to the Lefebvre's model for LBO and classical perfect stirred reactor (PSR) concept,a load parameter (LP) is proposed for LBO analysis of aero-engine combustors in this paper.The parameters contained in load parameter are all estimated from the non-reacting flow field of a combustor that is obtained by numerical simulation.Additionally,based on the load parameter,a method of fuel iterative approximation (FIA) is proposed to predict the LBO limit of the combustor.Compared with experimental data for 19 combustors,it is found that load parameter can represent the actual combustion load of the combustor near LBO and have good relativity with LBO fuel/air ratio (FAR).The LBO FAR obtained by FIA shows good agreement with experimental data,the maximum prediction uncertainty of FIA is about ± 17.5%.Because only the non-reacting flow is simulated,the time cost of the LBO limit prediction using FIA is relatively low (about 6 h for one combustor with computer equipment of CPU 2.66 GHz × 4 and 4 GB memory),showing that FIA is reliable and efficient to be used for practical applications.

  1. 78 FR 56589 - Airworthiness Directives; PIAGGIO AERO INDUSTRIES S.p.A Airplanes

    Science.gov (United States)

    2013-09-13

    .... Request To Change Compliance Time From Hours Time-in-Service (TIS) to Landings Carlo Cardu of PIAGGIO AERO... Change the Requirement To Replace the Main Landing Gear (MLG) Lever Hinge Fitting (LHF) Carlo Cardu of... Clarify Inspection Requirements for Newly Installed MLG Carlo Cardu of PIAGGIO AERO INDUSTRIES...

  2. Parameter optimization analysis to minimize the polarization error in a localized thermal tunable fiber ring resonator gyro.

    Science.gov (United States)

    Bobbili, Prasada Rao; Nayak, Jagannath; Pinnoji, Prerana Dabral; Rama Koti Reddy, D V

    2016-03-10

    The accuracy of the resonant frequency servo loop is a major concern for the high-performance operation of a resonant fiber optic gyro. For instance, a bias error as large as tens or even hundreds of degrees/hour has been observed at the demodulated output of the resonant frequency servo loop. The traditional frequency servo mechanism is not an efficient tool to address this problem. In our previous work, we proposed a novel method to minimize the laser frequency noise to the level of the shot noise by refractive index modulation by a thermally tunable resonator. In this paper, we performed the parameter optimization for the resonator coil, multifunction integrated-optics chip, and couplers by the transition matrix using the Jones matrix methodology to minimize the polarization error. With the optimized parameter values, we achieved the bias value of the resonator fiber optic gyro to 1.924°/h.

  3. A comparison of three adsorption equations and sensitivity study of parameter uncertainty effects on adsorption refrigeration thermal performance estimation

    Science.gov (United States)

    Zhao, Yongling; Hu, Eric; Blazewicz, Antoni

    2012-02-01

    This paper presents isosteric-based adsorption equilibrium tests of three activated carbon samples with methanol as an adsorbate. Experimental data was fitted into Langmuir equation, Freundlich equation and Dubinin-Astakov (D-A) equation, respectively. The fitted adsorption equations were compared in terms of agreement with experimental data. Moreover, equation format's impacts on calculation of the coefficient of performance (COP) and refrigeration capacity of an adsorption refrigeration system was analyzed. In addition, the sensitivity of each parameter in each adsorption equation format to the estimation of cycle's COP and refrigeration capacity was investigated. It was found that the D-A equation is the best form for presenting the adsorptive property of a carbon-methanol working pair. The D-A equation is recommended for estimating thermal performance of an adsorption refrigeration system because simulation results obtained using the D-A equation are less sensitive to errors of experimentally determined D-A equation's parameters.

  4. The Physics of Boundary-Layer Aero-Optic Effects

    Science.gov (United States)

    2012-09-01

    index-of refraction in turn depends on the media density, ρ, via a Gladstone -Dale relation, [1], ’)1( nKnK GDGD =−=ρ , where KGD is a Gladstone -Dale...6. References [1] Gladstone , J. H., Dale, T. P. 1863 “Researches on the Refraction, Dispersion, and Sensitiveness of Liquids”, Philosophical...AIAA J, 7 9 ( 1969 ), pp. 1737–1743. [9] R.J. Hugo and E.J. Jumper, ”Applicability of the Aero-Optic Linking Equation to a Highly Coherent

  5. Aero-acoustic noise of wind turbines. Noise prediction models

    Energy Technology Data Exchange (ETDEWEB)

    Maribo Pedersen, B. [ed.

    1997-12-31

    Semi-empirical and CAA (Computational AeroAcoustics) noise prediction techniques are the subject of this expert meeting. The meeting presents and discusses models and methods. The meeting may provide answers to the following questions: What Noise sources are the most important? How are the sources best modeled? What needs to be done to do better predictions? Does it boil down to correct prediction of the unsteady aerodynamics around the rotor? Or is the difficult part to convert the aerodynamics into acoustics? (LN)

  6. Interference Analysis Status and Plans for Aeronautical Mobile Airport Communications System (AeroMACS)

    Science.gov (United States)

    Kerczewski, Robert J.; Wilson, Jeffrey D.

    2010-01-01

    Interference issues related to the operation of an aeronautical mobile airport communications system (AeroMACS) in the C-Band (specifically 5091-5150 MHz) is being investigated. The issue of primary interest is co-channel interference from AeroMACS into mobile-satellite system (MSS) feeder uplinks. The effort is focusing on establishing practical limits on AeroMACS transmissions from airports so that the threshold of interference into MSS is not exceeded. The analyses are being performed with the software package Visualyse Professional, developed by Transfinite Systems Limited. Results with omni-directional antennas and plans to extend the models to represent AeroMACS more accurately will be presented. These models should enable realistic analyses of emerging AeroMACS designs to be developed from NASA Test Bed, RTCA 223, and European results.

  7. An experimental study of aero-optical aberration and dithering of supersonic mixing layer via BOS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The optical performance of supersonic mixing layer is heavily deteriorated by the aero-optical aberration and dithering of coherent structures, but current measuring methods limit the spatiotemporal resolution in relevant studies. A high resolution whole-field aero-optical aberration and dithering measuring method based on the Background Orient Schlieren (BOS) technique was studied. The systematic structure, sensitivity and resolution of BOS are analyzed in this paper. The aero-optical aberration and dithering of streamwise structures in supersonic mixing layers were quantificationally studied with BOS. The aberration field of spanwise structures revealed the ribbon-like aberration structures, which heavily restrict the optical performance of a mixing layer. The quantifications of aero-optical aberration and dithering are very important in studying aero-optical performance of supersonic mixing layer.

  8. Global dust model intercomparison in AeroCom phase I

    Directory of Open Access Journals (Sweden)

    N. Huneeus

    2010-10-01

    Full Text Available Desert dust plays an important role in the climate system through its impact on Earth's radiative budget and its role in the biogeochemical cycle as a source of iron in high-nutrient-low-chlorophyll regions. A large degree of diversity exists between the many global models that simulate the dust cycle to estimate its impact on climate. We present the results of a broad intercomparison of a total of 15 global aerosol models within the AeroCom project. Each model is compared to observations focusing on variables responsible for the uncertainties in estimating the direct radiative effect and the dust impact on the biogeochemical cycle, i.e., aerosol optical depth (AOD and dust deposition. Additional comparisons to Angström Exponent (AE, coarse mode AOD and dust surface concentration are included to extend the assessment of model performance. These datasets form a benchmark data set which is proposed for model inspection and future dust model developments. In general, models perform better in simulating climatology of vertically averaged integrated parameters (AOD and AE in dusty sites than they do with total deposition and surface concentration. Almost all models overestimate deposition fluxes over Europe, the Indian Ocean, the Atlantic Ocean and ice core data. Differences among the models arise when simulating deposition at remote sites with low fluxes over the Pacific and the Southern Atlantic Ocean. This study also highlights important differences in models ability to reproduce the deposition flux over Antarctica. The cause of this discrepancy could not be identified but different dust regimes at each site and issues with data quality should be considered. Models generally simulate better surface concentration at stations downwind of the main sources than at remote ones. Likewise, they simulate better surface concentration at stations affected by Saharan dust than at stations affected by Asian dust. Most models simulate the gradient in AOD and

  9. Understanding Aero-Fractures using optics and acoustics

    Science.gov (United States)

    Turkaya, Semih; Toussaint, Renaud; Kvalheim Eriksen, Fredrik; Zecevic, Megan; Daniel, Guillaume; Grude Flekkøy, Eirik; Jørgen Måløy, Knut

    2016-04-01

    exponent p value around 0.5. An analytical model of overpressure diffusion predicting p = 0.5 and two other free parameters of the Omori Law (prefactor and origin time) is developed. The spatial density of the seismic events, and the time of end of formation of the channels can also be predicted using this developed model. Using direct simulations of acoustic emissions due to the air vibration in opening fractal cavities, the evolution in the power spectrum is investigated. 1. Turkaya S, Toussaint R, Eriksen FK, Zecevic M, Daniel G, Flekkøy EG, Måløy KJ. "Bridging aero-fracture evolution with the characteristics of the acoustic emissions in a porous medium." Front. Phys.3:70. 2015 doi: 10.3389/fphy.2015.00070

  10. Evaluation of the Effect of Operating Parameters on Thermal Performance of an Integrated Starter Generator in Hybrid Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Moo-Yeon Lee

    2015-08-01

    Full Text Available The belt-driven-type integrated starter generator motor in a hybrid electric vehicle is vulnerable to thermal problems owing to its high output power and proximity to the engine. These problems may cause demagnetization and insulation breakdown, reducing the performance and durability of the motor. Hence, it is necessary to evaluate the thermal performance and enhance the cooling capacity of the belt-driven type Integrated Starter Generator. In this study, the internal temperature variations of the motor were investigated with respect to the operating parameters, particularly the rotation speed and environment temperature. At a maximum ambient temperature of 105 °C and rotation speed (motor design point of 4500 rpm, the coil of the motor was heated to approximately 189 °C in generating mode. The harsh conditions of the starting mode were analyzed by assuming that the motor operates during the start-up time at a maximum ambient temperature of 105 °C and rotation speed (motor design point of 800 rpm; the coil was heated to approximately 200 °C, which is close to the insulation temperature limit. The model for analyzing the thermal performance of the ISG was verified by comparing its results with those obtained through a generating-mode-based experiment

  11. Physics parameter calculations for a Tandem Mirror Reactor with thermal barriers

    Energy Technology Data Exchange (ETDEWEB)

    Boghosian, B.M.; Lappa, D.A.; Logan, B.G.

    1979-11-06

    Thermal barriers are localized reductions in potential between the plugs and the central cell, which effectively insulate trapped plug electrons from the central cell electrons. By then applying electron heating in the plug, it is possible to obtain trapped electron temperatures that are much greater than those of the central cell electrons. This, in turn, effects an increase in the plug potential and central cell confinement with a concomitant decrease in plug density and injection power. Ions trapped in the barrier by collisions are removed by the injection of neutral beams directed inside the barrier cell loss cone; these beam neutrals convert trapped barrier ions to neutrals by charge exchange permitting their escape. We describe a zero-dimensional physics model for this type of reactor, and present some preliminary results for Q.

  12. Influence of Fuzzy Parameters on the Modeling Quality of XLPE Insulation Properties under Thermal Aging

    Directory of Open Access Journals (Sweden)

    Lakhdar Bessissa

    2016-03-01

    Full Text Available In this work, we have used the fuzzy logic approach to predict mechanical properties (hot set test of cross-linked polyethylene (XLPE used as insulation in high voltage cables. The studied property presents non linear variations according to the aging time under high temperatures. So it is very difficult to find a theoretical or experimental model of the properties evolution under thermal aging. For that reason, several factors have been considered such as aging time and applied temperature. The obtained results are very encouraging and pointed out that the fuzzy logic is a powerful tool to predict the insulation proprieties. In other words, the obtained results are in good accordance with the experimental results with an acceptable error margin.

  13. Overview of additive manufacturing activities at MTU aero engines

    Science.gov (United States)

    Bamberg, Joachim; Dusel, Karl-Heinz; Satzger, Wilhelm

    2015-03-01

    Additive Manufacturing (AM) is a promising technology to produce parts easily and effectively, just by using metallic powder or wire as starting material and a sophisticated melting process. In contrast to milling or turning technologies complex shaped and hollow parts can be built up in one step. That reduces the production costs and allows the implementation of complete new 3D designs. Therefore AM is also of great interest for aerospace and aero engine industry. MTU Aero Engines has focused its AM activities to the selective laser melting technique (SLM). This technique uses metallic powder and a laser for melting and building up the part layer by layer. It is shown which lead part was selected for AM and how the first production line was established. A special focus is set on the quality assurance of the selective laser melting process. In addition to standard non-destructive inspection techniques a new online monitoring tool was developed and integrated into the SLM machines. The basics of this technique is presented.

  14. Fuzzy Computing for Control of Aero Gas Turbine Engines .

    Directory of Open Access Journals (Sweden)

    S. R. Balakrishnan

    1994-10-01

    Full Text Available Many methods, techniques and procedures available for designing the control system of plants and processes, are applied only after knowing accurately the plant or process to be controlled. However, in some complex situations where plants/processes cannot be accurately modelled, and especially where their control has human interaction, controller design may not be completely satisfactory. In such cases, it has been found that control decisions can be made on the basis of heuristic/linguistic measures or fuzzy algorithms. Fuzzy set principles have been used in controlling various plants/processes ranging from a laboratory steam engine to an autopilot, including an aero gas turbine engine engine for which the response of the engine speed for a fuzzy input of fuel flow has been studied. In this paper, certain stipulations and logic are suggested for the control of the total gas turbine engine. A case study of a single spool aero gas turbine engine with one of its state variables varied by heuristic logic is presented.

  15. Direct observation of magnetocaloric effect by differential thermal analysis: Influence of experimental parameters

    Energy Technology Data Exchange (ETDEWEB)

    Rotstein Habarnau, Yamila; Bergamasco, Pablo [Departamento Materia Condensada, CAC, CNEA, Av. Gral Paz 1429, San Martin 1650 (Argentina); Departamento de Fisica, FCEN, Universidad de Buenos Aires, Ciudad Universitaria Pab. I, Buenos Aires 1428 (Argentina); Sacanell, Joaquin [Departamento Materia Condensada, CAC, CNEA, Av. Gral Paz 1429, San Martin 1650 (Argentina); Leyva, Gabriela [Departamento Materia Condensada, CAC, CNEA, Av. Gral Paz 1429, San Martin 1650 (Argentina); Escuela de Ciencia y Tecnologia, UNSAM, San Martin, Buenos Aires 1650 (Argentina); Albornoz, Cecilia [Departamento Materia Condensada, CAC, CNEA, Av. Gral Paz 1429, San Martin 1650 (Argentina); Quintero, Mariano, E-mail: mquinter@cnea.gov.ar [Departamento Materia Condensada, CAC, CNEA, Av. Gral Paz 1429, San Martin 1650 (Argentina); Escuela de Ciencia y Tecnologia, UNSAM, San Martin, Buenos Aires 1650 (Argentina)

    2012-08-15

    The magnetocaloric effect is the isothermal change of magnetic entropy and the adiabatic temperature change induced in a magnetic material when an external magnetic field is applied. In this work, we present an experimental setup to study this effect in metamagnetic transitions, using the differential thermal analysis technique, which consists in measuring simultaneously the temperatures of the sample of interest and a reference one while an external magnetic field ramp is applied. We have tested our system to measure the magnetocaloric effect in La{sub 0.305}Pr{sub 0.32}Ca{sub 0.375}MnO{sub 3}, which presents phase separation effects at low temperatures (T<200 K). We obtain {Delta}T vs H curves, and analyze how the effect varies by changing the rate of the magnetic field ramp. Our results show that the intensity of the effect increases with the magnetic field change rate. We also have obtained the effective heat capacity of the system without the sample by performing calorimetric measurements using a pulse heat method, fitting the temperature change with a two tau description. With this analysis, we are able to describe the influence of the environment and subtract it to calculate the adiabatic temperature change of the sample.

  16. A Numerical Procedure to Obtain the Creep Parameters of the Thermal Barrier Coating

    Directory of Open Access Journals (Sweden)

    Shifeng Wen

    2014-05-01

    Full Text Available Three-point bending creep test was used to understand the creep behavior of typical thin film/substrate systems—thermal barrier coating (TBC systems. Firstly, a simplified model, which does not consider the local effect, has been set up to get an analytical relationship. The important result is that creep stress exponent of materials is equal to the creep load exponent of the steady-state deflection rate of BC specimens. Secondly, in order to consider the local effect of bending, the finite element method (FEM has been carried out. FEM calculation shows that there is a steady stage of the creep deflection under a constant applied load. And the exponent of the steady-state creep deflection rate to the applied load is found to be equal to the creep stress exponent of materials. The creep constant of the materials can be obtained by a set of trials with assumed creep constants of materials and can be finally determined by the best fit method. Finally, the finite element results show that the influences of the friction, the thickness of TBCs, and the modulus ratio of TBC to the substrate on stress distribution are important.

  17. Parameter-free numerical method for modeling thermal convection in square cavities in a wide range of Rayleigh numbers

    Science.gov (United States)

    Goloviznin, V. M.; Korotkin, I. A.; Finogenov, S. A.

    2016-12-01

    Some numerical results for the two- and three-dimensional de Vahl Davis benchmark are presented. This benchmark describes thermal convection in a square (cubic) cavity with vertical heated walls in a wide range of Rayleigh numbers (104 to 1014), which covers both laminar and highly turbulent f lows. Turbulent f lows are usually described using a turbulence model with parameters that depend on the Rayleigh number and require adjustment. An alternative is Direct Numerical Simulation (DNS) methods, but they demand extremely large computational grids. Recently, there has been an increasing interest in DNS methods with an incomplete resolution, which, in some cases, are able to provide acceptable results without resolving Kolmogorov scales. On the basis of this approach, the so-called parameter-free computational techniques have been developed. These methods cover a wide range of Rayleigh numbers and allow computing various integral properties of heat transport on relatively coarse computational grids. In this paper, a new numerical method based on the CABARET scheme is proposed for solving the Navier-Stokes equations in the Boussinesq approximation. This technique does not involve a turbulence model or any tuning parameters and has a second-order approximation scheme in time and space on uniform and nonuniform grids with a minimal computational stencil. Testing the technique on the de Vahl Davis benchmark and a sequence of refined grids shows that the method yields integral heat f luxes with a high degree of accuracy for both laminar and highly turbulent f lows. For Rayleigh numbers up to 1014, a several percent accuracy is achieved on an extremely coarse grid consisting of 20 × 20 cells refined toward the boundary. No definite or comprehensive explanation of this computational phenomenon has been given. Cautious optimism is expressed regarding the perspectives of using the new method for thermal convection computations at low Prandtl numbers typical of liquid metals.

  18. Thermally induced changes of optical and vital parameters in human cancer cells

    Science.gov (United States)

    Dressler, C.; Schwandt, D.; Beuthan, J.; Mildaziene, V.; Zabarylo, U.; Minet, O.

    2010-11-01

    Minimally invasive laser-induced thermotherapy (LITT) presents an alternative method to conventional tumor therapeutically interventions, such as surgery, chemotherapy, radiotherapy or nuclear medicine. Optical tissue characteristics of tumor cells and their heat-induced changes are essential issues for controlling LITT progressions. Therefore, it is indispensable to exactly know the absorption coefficient μa, the scattering coefficient μs and the anisotropy factor g as well as their changes under rising temperatures in order to simulate the treatment parameters successfully. Optical parameters of two different cancer model tissues - breast cancer cells species MX1 and colon cancer cells species CX1 - were measured in the spectral range 400 - 1100 nm as well as in the temperature range 37 - 60°C. The absorption coefficient of both cell species was low throughout the spectral range analyzed, while μs of both species rose with increasing temperatures. The anisotropy factor g however dropped for both tissues with increasing temperatures. Light scatterings inside tissues proceeded continuously forward for all species tested. It was demonstrated that optical tissue properties undergo significant changes along with the vital status of the cells when the temperature increases.

  19. Influence of high rotational speeds on heat transfer and oil film thickness in aero-engine bearing chambers

    Science.gov (United States)

    Wittig, S.; Glahn, A.; Himmelsbach, J.

    1994-04-01

    Increasing the thermal loading of bearing chambers in modern aero-engines requires advanced techniques for the determination of heat transfer characteristics. In the present study, film thickness and heat transfer measurements have been carried out for the complex two-phase oil/air flow in bearing chambers. In order to ensure real engine conditions, a new test facility has been built up, designed for rotational speeds up to n = 16,000 rpm and maximum flow temperatures of T(sub max) = 473 K. Sealing air and lubrication oil flow can be varied nearly in the whole range of aero-engine applications. Special interest is directed toward the development of an ultrasonic oil film thickness measuring technique, which can be used without any reaction on the flow inside the chamber. The determination of local heat transfer at the bearing chamber housing is based on a well-known temperature gradient method using surface temperature measurements and a finite element code to determine temperature distributions within the bearing chamber housing. The influence of high rotational speed on the local heat transfer and the oil film thickness is discussed.

  20. Parameter Survey of Thermally Highly Loaded, Porous and Cooled Multi-Layer Systems for Turbine Blades

    Institute of Scientific and Technical Information of China (English)

    Peng Shan; Dieter Bohn; Jing Ren; N.Surken

    2007-01-01

    This study is an advanced investigation for the cooling of high temperature turbine vanes and blades. The efficient heat exchanging near the surface of a blade may be achieved by forcing a cooling air flow emitting out of a thin layer of the porous metal which is pasted on the structural high strength metal. The contents include the consideration on the computational model of heat transfer through a layer of porous material, the concrete modeling and the analysis of the model, the numerical survey of key parameters for both the two-layer porous materials and the heat transfer fluid flow passing through the model channels. The results revealed that the constructed system is reasonable. Proposed an evaluation formula for the porous material heat transfer efficiency.

  1. Evaluation of the Molecular Structural Parameters of Normal Rice Starch and Their Relationships with Its Thermal and Digestion Properties

    Directory of Open Access Journals (Sweden)

    Lingshang Lin

    2017-09-01

    Full Text Available The molecular structural parameters of six normal rice starches with different amylose contents were investigated through their iodine absorption spectra and gel permeation chromatography of fully branched and debranched starches. The thermal and digestion properties of starches were also determined and their relationships with molecular structural parameters were analyzed. Results showed that the molecular structural parameters of maximum absorption wavelength, blue value (BV, optical density 620 nm/550 nm (OD 620/550, amylose, intermediate component, and amylopectin, including its short branch-chains, long branch-chains, and branching degree, had high correlation in different determining methods. The intermediate component of starch was significantly positively related to amylose and negatively related to amylopectin, and the amylopectin branching degree was significantly positively related to amylopectin content and negatively related to amylose content. The gelatinization temperatures and enthalpy of native starch were significantly positively related to BV, OD 620/550, and amylose content and negatively related to amylopectin short branch-chains. The gelatinization temperatures and enthalpy of retrograded starch were significantly negatively related to amylopectin branching degree. The digestions of gelatinized and retrograded starches were significantly negatively related to the BV, OD 620/550, amylose, and intermediate component and positively related to amylopectin and its short branch-chains and branching degree.

  2. Higher Order Elastic Constants, Gruneisen Parameters and Lattice Thermal Expansion of Lithium Niobate

    Directory of Open Access Journals (Sweden)

    Thresiamma Philip

    2006-01-01

    Full Text Available The second and third-order elastic constants and pressure derivatives of second- order elastic constants of trigonal LiNbO3 (lithium niobate have been obtained using the deformation theory. The strain energy density estimated using finite strain elasticity is compared with the strain dependent lattice energy density obtained from the elastic continuum model approximation. The second-order elastic constants and the non-vanishing third-order elastic constants along with the pressure derivatives of trigonal LiNbO3 are obtained in the present work. The second and third-order elastic constants are compared with available experimental values. The second-order elastic constant C11 which corresponds to the elastic stiffness along the basal plane of the crystal is less than C33 which corresponds to the elastic stiffness tensor component along the c-axis of the crystal. The pressure derivatives, dC'ij/dp obtained in the present work, indicate that trigonal LiNbO3 is compressible. The higher order elastic constants are used to find the generalized Gruneisen parameters of the elastic waves propagating in different directions in LiNbO3. The Brugger gammas are evaluated and the low temperature limit of the Gruneisen gamma is obtained. The results are compared with available reported values.

  3. Determination of reliability parameters of radioelectronic devices determined by thermal modes

    Directory of Open Access Journals (Sweden)

    A. V. Nikitchuk

    2014-06-01

    Full Text Available Statement of the problem. The reliability is important (and sometimes crucial functional characteristic for RED. So it is necessary to analyze the impact on them of destabilizing external factors - mechanical, temperature, humidity, ionizing radiation. Structural-design elements RED. SCM are the main objects for which you first need to determine the temperature of the ЕЕS and performance reliability. Determination of the temperature of the EES cells and microassemblies. The basic mathematical models are presented to determine the temperatures of the electronic structure elements of cells and microassemblies. Indicators of HEE reliability as a function of their temperature. The value of the operational failure rate of most groups RED calculated by mathematical models. These indicators include: basic failure rate, the rate regime, the coefficients that take into account changes in operational failure rate depending on various factors. Software definition of reliability parameters. The software product allows you to switch from "manual" calculation reliability REDs to a fully automated modeling components. The program is applicable for calculating the reliability and to find a more "sustainable" elements to increase the probability of failure-free operation. Conclusions. Primary tasks performed in the work are listed

  4. Higher Order Elastic Constants, Gruneisen Parameters and Lattice Thermal Expansion of Trigonal Calcite

    Directory of Open Access Journals (Sweden)

    Thresiamma Phlip

    2005-01-01

    Full Text Available The second- and third-order elastic constants of trigonal calcite have been obtained using the deformation theory. The strain energy density derived using the deformation theory is compared with the strain dependent lattice energy obtained from the elastic continuum model approximation to get the expressions for the second- and third-order elastic constants. Higher order elastic constants are a measure of the anharmonicity of a crystal lattice. The seven second-order elastic constants and the fourteen non-vanishing third-order elastic constants of trigonal calcite are obtained. The second-order elastic constants C11, which corresponds to the elastic stiffness along the basal plane of the crystal is greater than C33, which corresponds to the elastic stiffness tensor component along the c-axis of the crystal. First order pressure derivatives of the second-order elastic constants of calcite are evaluated. The higher order elastic constants are used to find the generalized Gruneisen parameters of the elastic waves propagating in different directions in calcite. The Brugger gammas are evaluated and the low temperature limit of the Gruneisen gamma is obtained. The results are compared with available reported values.

  5. Magnetic field-induced changes of lattice parameters and thermal expansion behavior of the CoMnSi compound

    Energy Technology Data Exchange (ETDEWEB)

    Kou, R. H.; Gao, J.; Wang, G.; Liu, Y. D.; Wang, Y. D.; Ren, Y.; Brown, D. E.

    2016-02-01

    The crystal structure of the CoMnSi compound during zero-field cooling and field cooling from room temperature down to 200 K was studied using the synchrotron radiation X-ray diffraction technique. The results show that the lattice parameters and thermal expansion behavior of the sample are changed by the applied magnetic fields. The lattice contracts along the a axis, but expands along the b and c axes. Due to enlarged and anisotropic changes under a magnetic field of 6 T, the lattice shows an invar-like behavior along all three axes. Critical interatomic distances and bond angles also show large changes under the influence of such a high magnetic field. These magnetic field-induced changes of the lattice are discussed with respect to their contributions to the large magnetocaloric effect of the CoMnSi compound.

  6. Strong thermal Leptogenesis: an exploded view of the low energy neutrino parameters in the SO(10)-inspired model

    CERN Document Server

    Marzola, Luca

    2014-01-01

    Leptogenesis is an attractive scenario in which neutrino masses and baryon asymmetry of the Universe are explained together under a minimal set of assumptions. After formulating the problem of initial conditions and introducing the strong thermal leptogenesis conditions as solution, we show that, within the framework provided by the \\soten~model of leptogenesis, the latter lead to a set of testable predictions on the same neutrino parameters currently under experimental investigations. The emerging scenario selects the normal ordering of the neutrino mass pattern, a large value for the reactor mixing angle, $2\\deg \\lesssim \\theta_{13} \\lesssim 20\\deg$, as well as a non maximal atmospheric mixing angle, $16\\deg \\lesssim \\theta_{23} \\lesssim 41\\deg$, and favours negative values for the Dirac phase \\delta. The signature of the proposed strong thermal \\soten~solutions is in the relation obtained between the effective Majorana mass and the lightest neutrino mass: $m_{ee} \\approx 0.8 \\, m_1 \\approx 15 $ meV.

  7. Spectral, mechanical, thermal, optical and solid state parameters, of metal-organic bis(hydrogenmaleate)-CO(II) tetrahydrate crystal

    Energy Technology Data Exchange (ETDEWEB)

    Chandran, Senthilkumar [Centre for Crystal Growth, Department of Physics, SSN College of Engineering, Kalavakkam 603110 (India); Jagan, R. [Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036 (India); Paulraj, Rajesh, E-mail: rajeshp@ssn.edu.in [Centre for Crystal Growth, Department of Physics, SSN College of Engineering, Kalavakkam 603110 (India); Ramasamy, P. [Centre for Crystal Growth, Department of Physics, SSN College of Engineering, Kalavakkam 603110 (India)

    2015-10-15

    Metal-organic bis(hydrogenmaleate)-Co(II) tetrahydrate single crystals have been grown by slow evaporation solution growth technique at room temperature. The crystal structure and the unit cell parameters were analyzed from the X-ray diffraction studies. Single-crystal X-ray diffraction analyses reveal that the grown crystal belongs to triclinic system with the space group P-1. Functional groups in bis(hydrogenmaleate)-Co(II) tetrahydrate were identified by Fourier transform infrared spectral analysis. The peak observed at 663 cm{sup −1} is assigned to the (Co–O) stretching vibrations. The optical transmission of the crystal was studied by UV–vis–NIR spectral analysis. The photoluminescence emission studies were carried out for the title compound in a wide wavelength range between 350 nm and 550 nm at 303 K. Mechanical strength was tested by Vickers microhardness test. The laser damage threshold value has been determined using Nd:YAG laser operating at 1064 nm. At various frequencies and temperatures the dielectric behavior of the material was investigated. Solid state parameters such as plasma energy, Penn gap, Fermi energy and electronic polarizability were evaluated. Photoconductivity measurements were carried out for the grown crystal in the presence of DC electric field at room temperature. Thermal stability and decomposition of the crystal were studied by TG–DTA. The weight loss of the title compound occurs in different steps. - Graphical abstract: Molecular structure of the bis(hydrogenmaleate)-Co(II) tetrahydrate drawn at 40% ellipsoid probability level. - Highlights: • Bis(hydrogenmaleate)-Co(II) tetrahydrate single crystal is grown by slow evaporation method. • Structural and optical properties were discussed. • The title complex crystal is thermally stable up to 91 °C. • Plasma energy, Fermi energy and electronic polarizability are evaluated. • It exhibits positive photoconductivity.

  8. Selection of excipients for melt extrusion with two poorly water-soluble drugs by solubility parameter calculation and thermal analysis.

    Science.gov (United States)

    Forster, A; Hempenstall, J; Tucker, I; Rades, T

    2001-09-11

    The aim of this study was to determine the miscibility of drug and excipient to predict if glass solutions are likely to form when drug and excipient are melt extruded. Two poorly water-soluble drugs, indomethacin and lacidipine, were selected along with 11 excipients (polymeric and non-polymeric). Estimation of drug/excipient miscibility was performed using a combination of the Hoy and Hoftzyer/Van Krevelen methods for Hansen solubility parameter calculation. Miscibility was experimentally investigated with differential scanning calorimetry (DSC) and hot stage microscopy (HSM). Studies were performed at drug/excipient ratios, 1:4, 1:1 and 4:1. Analysis of the glass transition temperature (T(g)) was performed by quench cooling drug/excipient melts in the DSC. Differences in the drug/excipient solubility parameters of 10 MPa(1/2) were expected to indicate a lack of miscibility and not form glass solutions when melt extruded. Experimentally, miscibility was shown by changes in drug/excipient melting endotherms and confirmed by HSM investigations. Experimental results were in agreement with solubility parameter predictions. In addition, drug/excipient combinations predicted to be largely immiscible often exhibited more than one T(g) upon reheating in the DSC. Melt extrusion of miscible components resulted in amorphous solid solution formation, whereas extrusion of an "immiscible" component led to amorphous drug dispersed in crystalline excipient. In conclusion, combining calculation of Hansen solubility parameters with thermal analysis of drug/excipient miscibility can be successfully applied to predict formation of glass solutions with melt extrusion.

  9. Predicting Cavitation on Marine and Hydrokinetic Turbine Blades with AeroDyn V15.04

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Robynne [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-14

    Cavitation is an important consideration in the design of marine and hydrokinetic (MHK) turbines. The National Renewable Energy Laboratory's AeroDyn performance code was originally developed for horizontal-axis wind turbines and did not have the capability to predict cavitation inception. Therefore, AeroDyn has been updated to include the ability to predict cavitation on MHK turbines based on user-specified vapor pressure and submerged depth. This report outlines a verification of the AeroDyn V15.04 performance code for MHK turbines through a comparison to publicly available performance data.

  10. GPS radio occultation with CHAMP and SAC-C: global monitoring of thermal tropopause parameters

    Directory of Open Access Journals (Sweden)

    T. Schmidt

    2005-01-01

    Full Text Available In this study the global lapse-rate tropopause (LRT pressure, temperature, potential temperature, and sharpness are discussed based on Global Positioning System (GPS radio occultations (RO from the German CHAMP (CHAllenging Minisatellite Payload and the U.S.-Argentinian SAC-C (Satelite de Aplicaciones Cientificas-C satellite missions. Results with respect to seasonal variations are compared with operational radiosonde data and ECMWF (European Centre for Medium-Range Weather Forecast operational analyses. Results on the tropical quasi-biennial oscillation (QBO are updated from an earlier study. CHAMP RO data are available continuously since May 2001 with on average 150 high resolution temperature profiles per day. SAC-C data are available for several periods in 2001 and 2002. In this study temperature data from CHAMP for the period May 2001-December 2004 and SAC-C data from August 2001-October 2001 and March 2002-November 2002 were used, respectively. The bias between GPS RO temperature profiles and radiosonde data was found to be less than 1.5K between 300 and 10hPa with a standard deviation of 2-3K. Between 200-20hPa the bias is even less than 0.5K (2K standard deviation. The mean deviations based on 167699 comparisons between CHAMP/SAC-C and ECMWF LRT parameters are (-2.1±37.1hPa for pressure and (0.1±4.2K for temperature. Comparisons of LRT pressure and temperature between CHAMP and nearby radiosondes (13230 resulted in (5.8±19.8hPa and (-0.1±3.3K, respectively. The comparisons between CHAMP/SAC-C and ECMWF show on average the largest differences in the vicinity of the jet streams with up to 700m in LRT altitude and 3K in LRT temperature, respectively. The CHAMP mission generates the first long-term RO data set. Other satellite missions will follow (GRACE, COSMIC, MetOp, TerraSAR-X, EQUARS generating together some thousand temperature profiles daily.

  11. Aero-Acoustic Moldeling using Large Eddy Simulation

    DEFF Research Database (Denmark)

    Shen, Wen Zhong; Sørensen, Jens Nørkær

    2008-01-01

    The flow-acoustic splitting technique for aero-acoustic computations is extended to simulate the propagation of acoustic waves generated by three-dimensional turbulent flows. In the flow part, a sub-grid-scale turbulence model (the mixed model) is employed for Large-Eddy Simulations. The obtained...... instantaneous flow solution is employed as input for the acoustic part. At low Mach numbers the differences in scales and propagation speed between the flow and the acoustic field are quite large, hence different meshes and time-steps can be utilized for the two parts. The model is applied to compute flows past...... characteristics for angles of attack up to stall. For the acoustic solutions, predicted noise spectra are validated quantitatively against the experimental data of Brook et al. A parametrical study of the noise pattern for flows at angles of attack between 4 deg and 12 deg shows that the noise level is small...

  12. Prediction of Flow Regimes and Thermal Hydraulic Parameters in Two-Phase Natural Circulation by RELAP5 and TRACE Codes

    Directory of Open Access Journals (Sweden)

    Viet-Anh Phung

    2015-01-01

    Full Text Available In earlier study we have demonstrated that RELAP5 can predict flow instability parameters (flow rate, oscillation period, temperature, and pressure in single channel tests in CIRCUS-IV facility. The main goals of this work are to (i validate RELAP5 and TRACE capabilities in prediction of two-phase flow instability and flow regimes and (ii assess the effect of improvement in flow regime identification on code predictions. Most of the results of RELAP5 and TRACE calculation are in reasonable agreement with experimental data from CIRCUS-IV. However, both codes misidentified instantaneous flow regimes which were observed in the test with high speed camera. One of the reasons for the incorrect identification of the flow regimes is the small tube flow regime transition model in RELAP5 and the combined bubbly-slug flow regime in TRACE. We found that calculation results are sensitive to flow regime boundaries of RELAP5 which were modified in order to match the experimental data on flow regimes. Although the flow regime became closer to the experimental one, other predicted thermal hydraulic parameters showed larger discrepancy with the experimental data than with the base case calculations where flow regimes were misidentified.

  13. Spectral, mechanical, thermal, optical and solid state parameters, of metal-organic bis(hydrogenmaleate)-CO(II) tetrahydrate crystal

    Science.gov (United States)

    Chandran, Senthilkumar; Jagan, R.; Paulraj, Rajesh; Ramasamy, P.

    2015-10-01

    Metal-organic bis(hydrogenmaleate)-Co(II) tetrahydrate single crystals have been grown by slow evaporation solution growth technique at room temperature. The crystal structure and the unit cell parameters were analyzed from the X-ray diffraction studies. Single-crystal X-ray diffraction analyses reveal that the grown crystal belongs to triclinic system with the space group P-1. Functional groups in bis(hydrogenmaleate)-Co(II) tetrahydrate were identified by Fourier transform infrared spectral analysis. The peak observed at 663 cm-1 is assigned to the (Co-O) stretching vibrations. The optical transmission of the crystal was studied by UV-vis-NIR spectral analysis. The photoluminescence emission studies were carried out for the title compound in a wide wavelength range between 350 nm and 550 nm at 303 K. Mechanical strength was tested by Vickers microhardness test. The laser damage threshold value has been determined using Nd:YAG laser operating at 1064 nm. At various frequencies and temperatures the dielectric behavior of the material was investigated. Solid state parameters such as plasma energy, Penn gap, Fermi energy and electronic polarizability were evaluated. Photoconductivity measurements were carried out for the grown crystal in the presence of DC electric field at room temperature. Thermal stability and decomposition of the crystal were studied by TG-DTA. The weight loss of the title compound occurs in different steps.

  14. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Directory of Open Access Journals (Sweden)

    Li Xun

    2015-10-01

    Full Text Available GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within ±0.01 mm, the roughness is less than 0.4 μm, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  15. Surface integrity of GH4169 affected by cantilever finish grinding and the application in aero-engine blades

    Institute of Scientific and Technical Information of China (English)

    Li Xun; Ma Shuang; Meng Fanjun

    2015-01-01

    GH4169 is the main material for aero-engine blades and integrated blisks. Because GH4169 has a poor milling performance, the profile precision and surface integrity of blades and integrated blisks are difficult to be met by utilizing the conventional milling process, which directly influence the global performance and reliability of aero-engines. Through grinding experiments on parameters and surface integrity optimization, the helical cantilever grinding process utilizing a 300# CBN RB wheel is presented and applied in finish machining of GH4169 blades. The profile errors of the blade surface are within ±0.01 mm, the roughness is less than 0.4 lm, the residual compressive stresses and the hardening rate are appropriate, there are no phenomena of burr and smearing with the grinding chips, and the leading/trailing edge can be smoothly connected with the suction/pressure surface. All the experimental results indicate that this grinding process is greatly suitable for the profile finish machining of GH4169 blades.

  16. Uncertainty of measurement for large product verification: evaluation of large aero gas turbine engine datums

    Science.gov (United States)

    Muelaner, J. E.; Wang, Z.; Keogh, P. S.; Brownell, J.; Fisher, D.

    2016-11-01

    Understanding the uncertainty of dimensional measurements for large products such as aircraft, spacecraft and wind turbines is fundamental to improving efficiency in these products. Much work has been done to ascertain the uncertainty associated with the main types of instruments used, based on laser tracking and photogrammetry, and the propagation of this uncertainty through networked measurements. Unfortunately this is not sufficient to understand the combined uncertainty of industrial measurements, which include secondary tooling and datum structures used to locate the coordinate frame. This paper presents for the first time a complete evaluation of the uncertainty of large scale industrial measurement processes. Generic analysis and design rules are proven through uncertainty evaluation and optimization for the measurement of a large aero gas turbine engine. This shows how the instrument uncertainty can be considered to be negligible. Before optimization the dominant source of uncertainty was the tooling design, after optimization the dominant source was thermal expansion of the engine; meaning that no further improvement can be made without measurement in a temperature controlled environment. These results will have a significant impact on the ability of aircraft and wind turbines to improve efficiency and therefore reduce carbon emissions, as well as the improved reliability of these products.

  17. Petrographic maturity parameters of a Devonian shale maturation series, Appalachian Basin, USA. ICCP Thermal Indices Working Group interlaboratory exercise

    Science.gov (United States)

    Araujo, Carla Viviane; Borrego, Angeles G.; Cardott, Brian; das Chagas, Renata Brenand A.; Flores, Deolinda; Goncalves, Paula; Hackley, Paul C.; Hower, James C.; Kern, Marcio Luciano; Kus, Jolanta; Mastalerz, Maria; Filho, João Graciano Mendonça; de Oliveira Mendonça, Joalice; Rego Menezes, Taissa; Newman, Jane; Suarez-Ruiz, Isabel; Sobrinho da Silva, Frederico; Viegas de Souza, Igor

    2014-01-01

    This paper presents results of an interlaboratory exercise on organic matter optical maturity parameters using a natural maturation series comprised by three Devonian shale samples (Huron Member, Ohio Shale) from the Appalachian Basin, USA. This work was conducted by the Thermal Indices Working Group of the International Committee for Coal and Organic Petrology (ICCP) Commission II (Geological Applications of Organic Petrology). This study aimed to compare: 1. maturation predicted by different types of petrographic parameters (vitrinite reflectance and spectral fluorescence of telalginite), 2. reproducibility of the results for these maturation parameters obtained by different laboratories, and 3. improvements in the spectral fluorescence measurement obtained using modern detection systems in comparison with the results from historical round robin exercises.Mean random vitrinite reflectance measurements presented the highest level of reproducibility (group standard deviation 0.05) for low maturity and reproducibility diminished with increasing maturation (group standard deviation 0.12).Corrected fluorescence spectra, provided by 14 participants, showed a fair to good correspondence. Standard deviation of the mean values for spectral parameters was lowest for the low maturity sample but was also fairly low for higher maturity samples.A significant improvement in the reproducibility of corrected spectral fluorescence curves was obtained in the current exercise compared to a previous investigation of Toarcian organic matter spectra in a maturation series from the Paris Basin. This improvement is demonstrated by lower values of standard deviation and is interpreted to reflect better performance of newer photo-optical measuring systems.Fluorescence parameters measured here are in good agreement with vitrinite reflectance values for the least mature shale but indicate higher maturity than shown by vitrinite reflectance for the two more mature shales. This red shift in

  18. Simulating Global AeroMACS Airport Ground Station Antenna Power Transmission Limits to Avoid Interference With Mobile Satellite Service Feeder Uplinks

    Science.gov (United States)

    Wilson, Jeffrey D.

    2013-01-01

    The Aeronautical Mobile Airport Communications System (AeroMACS), which is based upon the IEEE 802.16e mobile wireless standard, is expected to be implemented in the 5091 to 5150 MHz frequency band. As this band is also occupied by Mobile Satellite Service feeder uplinks, AeroMACS must be designed to avoid interference with this incumbent service. The aspects of AeroMACS operation that present potential interference are under analysis in order to enable the definition of standards that assure that such interference will be avoided. In this study, the cumulative interference power distribution at low Earth orbit from transmitters at global airports was simulated with the Visualyse Professional software. The dependence of the interference power on antenna distribution, gain patterns, duty cycle, and antenna tilt was simulated. As a function of these parameters, the simulation results are presented in terms of the limitations on transmitter power from global airports required to maintain the cumulative interference power under the established threshold.

  19. Junction temperature measurements via thermo-sensitive electrical parameters and their application to condition monitoring and active thermal control of power converters

    DEFF Research Database (Denmark)

    Baker, Nick; Liserre, Marco; Dupont, L.

    2013-01-01

    implementation of active thermal control to reduce losses and increase lifetime can be performed given an accurate knowledge of temperature. Temperature measurements via thermo-sensitive electrical parameters (TSEP) are one way to carry out immediate temperature readings on fully packaged devices. However...... scale implementation of these methods are discussed. Their potential use in the aforementioned goals in condition monitoring and active thermal control is also described....

  20. [Flight nurses' comprehension about their role in the multiprofesional team of aero-medical transport].

    Science.gov (United States)

    Scuissiato, Dayane Reinhardt; Boffi, Letícia Valois; da Rocha, Roseline da Rocha; Montezeli, Juliana Helena; Bordin, Michelle Taverna; Peres, Aida Maris

    2012-01-01

    This is a descriptive qualitative research which aimed at identifying the flight nurses' comprehension by about their role in the aero-medical multiprofesional team. A semi-structured interview was carried out with eight flight nurses from Curitiba-PR, from June to August 2009. The speeches were analyzed by the content analysis, from which three categories emerged. The first describes the responsibilities of the flight nurses as managers of the aero-medical mission, planning for before, during and after the transport, what includes the aircraft check-list and knowledge of the patient's case. The second category deals with aspects of these professionals as care providers to the aero-transferred patient. The third describes communication and team-work as fundamental requirements for flight nurses. It was concluded that the nurse in aero-medical team mixes management and caring in his/her professional practice by the use of specific competences.

  1. Aero-Engine Fault Diagnosis Using Improved Local Discriminant Bases and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Jianwei Cui

    2014-01-01

    Full Text Available This paper presents an effective approach for aero-engine fault diagnosis with focus on rub-impact, through combination of improved local discriminant bases (LDB with support vector machine (SVM. The improved LDB algorithm, using both the normalized energy difference and the relative entropy as quantification measures, is applied to choose the optimal set of orthogonal subspaces for wavelet packet transform- (WPT- based signal decomposition. Then two optimal sets of orthogonal subspaces have been obtained and the energy features extracted from those subspaces appearing in both sets will be selected as input to a SVM classifier to diagnose aero-engine faults. Experiment studies conducted on an aero-engine rub-impact test system have verified the effectiveness of the proposed approach for classifying working conditions of aero-engines.

  2. Integrated Reconfigurable Aero and Propulsion Control for Improved Flight Safety of Commercial Aircraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The main objective of this project is to develop and test a novel innovative Integrated Reconfigurable Aero & Propulsion Control (IRAP) system that achieves...

  3. Effects of deposition parameters on microstructure and thermal conductivity of diamond films deposited by DC arc plasma jet chemical vapor deposition

    Institute of Scientific and Technical Information of China (English)

    QU Quan-yan; QIU Wan-qi; ZENG De-chang; LIU Zhong-wu; DAI Ming-jiang; ZHOU Ke-song

    2009-01-01

    The uniform diamond films with 60 mm in diameter were deposited by improved DC arc plasma jet chemical vapor deposition technique. The structure of the film was characterized by scanning electronic microcopy(SEM) and laser Raman spectrometry. The thermal conductivity was measured by a photo thermal deflection technique. The effects of main deposition parameters on microstructure and thermal conductivity of the films were investigated. The results show that high thermal conductivity, 10.0 W/(K-cm), can be obtained at a CH4 concentration of 1.5% (volume fraction) and the substrate temperatures of 880-920 ℃ due to the high density and high purity of the film. A low pressure difference between nozzle and vacuum chamber is also beneficial to the high thermal conductivity.

  4. Sensitivity Analysis on Variation of Vane Natural Frequency of a Typical Aero Engine Impeller

    Directory of Open Access Journals (Sweden)

    Selwyn Anbarasan

    2015-08-01

    Full Text Available Centrifugal compressors are widely used in small and medium class turbo shaft and turbo prop aero engines. Inevitably the variation in the manufacturing process will lead to variation in natural frequency of blade vanes in an impeller which usually termed as Mistuning. The variation in natural frequency will increase the forced frequency response of the vanes than the tuned vanes. In-service deterioration of vanes dimension due to erosion, corrosion and FOD also adds to further variation in natural frequency. The amplification factor of the response will lead to reduced HCF life of the vanes than the tuned vanes. It is important for the designer to envisage the variation of natural frequency of the vanes to estimate the life of the impeller to avoid premature failure. This also helps in monitoring the health of the impeller during service. This paper deals with prediction of the effects of manufacturing/geometry variation and variation in material properties on impeller vane natural frequency of a turbo shaft engine. FEM model is created to accommodate the geometry variation of the impeller. The parameters influencing the natural frequency are varied and its corresponding variation in frequency is predicted. Several conditions are also simulated and sensitivity analysis is carried out with the above result to predict the order of influencing parameters. Influencing parameters are ranked and the most influencing parameter is found to be the Young’s Modulus of the material for this case of impeller. Maximum influencing parameter Young’s modulus contributes to 5.8% variation and the least contributing factor density to 0.6% variation in natural frequency. This result enables the designer to forecast the possible range of natural frequencies in the design phase, so that he can limit the analysis to predict the response due to mistuning to the estimated range of frequencies.

  5. A SERIES OF UNCOMMON FOREIGN BODIES PRESENTING IN THE AERO-DIGESTIVE TRACT

    Directory of Open Access Journals (Sweden)

    Jitendra Singh

    2016-02-01

    Full Text Available Foreign body impacted in the aero-digestive tract is one of the earliest reported problems. Coins, buttons, marbles, crayons, parts of toys etc. are the most commonly ingested foreign bodies in children. Fish, meat and chicken bones, dentures, nails etc.the most common foreign bodies ingested by adultsWe report a series of unusual foreign body ingestion in aero-digestive tract and their management by endoscopic retrieval.

  6. Corin/Dorin: A WDM-Enabled Platform for Aero-Engine Control Systems

    OpenAIRE

    Xia, Ming; Moslehi, Behzad; Mukherjee, Biswanath; Behbahani, Alireza; Millar, Richard

    2008-01-01

    The Full Authority Digital Electronic Control (FADEC) centralized architecture has become the norm in aero-engine control systems. With a centralized system, changes are costly and complex [1]. The goal of this work is to develop the architectural design concept for a distributed supporting network called Coarse WDM Optical Ring Network (CORIN) appropriate for aero-engine performance monitoring. A CORIN features high bandwidth, reliability, modularity, scalability, flexibility, an...

  7. Fault Diagnosis of Demountable Disk-Drum Aero-Engine Rotor Using Customized Multiwavelet Method

    OpenAIRE

    Jinglong Chen; Yu Wang; Zhengjia He; Xiaodong Wang

    2015-01-01

    The demountable disk-drum aero-engine rotor is an important piece of equipment that greatly impacts the safe operation of aircraft. However, assembly looseness or crack fault has led to several unscheduled breakdowns and serious accidents. Thus, condition monitoring and fault diagnosis technique are required for identifying abnormal conditions. Customized ensemble multiwavelet method for aero-engine rotor condition identification, using measured vibration data, is developed in this paper. Fir...

  8. Study on thermal decomposition kinetic parameters of GAP-TPE%GAP-TPE热分解动力学研究

    Institute of Scientific and Technical Information of China (English)

    左海丽; 肖乐勤; 周伟良; 徐复铭

    2011-01-01

    利用热量(TG)及微商热重(DTG),研究了GAP基含能热塑性弹性体(GAP-TPE)在氢气气氛、不同升温速率的热分解反应过程.根据GAP-TPE热解DTG曲线特点,把GAP-TPE热解过程分为3个阶段,用Kissinger法计算3个阶段的动力学参数,其活化能分别是223、235、57kJ/mol,lnA分别是52.73、49.39、8.28.用Ozawa法求得各阶段的平均活化能与Kinger法计算结果基本一致,并采用Coats-Redfen法求算了GAP-TPE热分解3个阶段可能遵循的动力学机理方程式分别为[ - ln(1 -α)]1/3、-ln(1-α)和-ln(1-α).%Based on the thermal analysis kinetics,thermogravimetric analysis(TG)and derivative thermogravimetry( DTG) were employed to evaluate the thermal decomposition behaviors of CAP-TPE in Ar atmosphere. A peak separation was performed to separate the thermal decomposition of CAP-TPE into three stages according to the characteristic of the experimental differential mass loss curve,and the kinetic parameters such as activation energy and pre-exponential were calculated and analyzed with Kissinger method. The activation energy of three stages were 223 kJ/mol ,233 kJ/mol and 57 kJ/mol, the hv4 were 52.73,49.39 and 8.28, respectively. The average activation energy was calculated with Ozawa methods in each decomposition stage is consistent with the result of Kissinger method. In addition,the mechanism functions of the three stage using the methods of Coats-Redfen were[ - ln( 1 -a) ]1/3, -ln(1-α) and - ln(1-α),respectively.

  9. Chemical reaction, thermal relaxation time and internal material parameter effects on MHD viscoelastic fluid with internal structure using the Cattaneo-Christov heat flux equation

    Science.gov (United States)

    Khan, Sabeel M.; Hammad, M.; Sunny, D. A.

    2017-08-01

    In this article, the influence of thermal relaxation time and chemical reaction is studied on the MHD upper-convected viscoelastic fluid with internal structure using the Cattaneo-Christov heat flux equation for the first time in the literature. The flow-governing equations are formulated and are converted into their respective ordinary differential equations (ODEs) with the application of similarity functions. The resulting system of coupled nonlinear ODEs is solved along with the prescribed conditions at boundary using a finite-difference code in MATLAB. Influence of chemical reaction, thermal relaxation time and internal material parameter on the macroscopic and micropolar velocities as well as on the temperature and concentration profiles is examined along with other physical parameters ( e.g., magnetic parameter, Eckert number, Prandtl number and fluid relaxation time). The accuracy of the obtained numerical solution is shown by comparing the physical parameters of interest with particular cases of existing results in the literature.

  10. Effect of high-pressure processing and thermal pasteurization on overall quality parameters of white grape juice.

    Science.gov (United States)

    Chang, Yin-Hsuan; Wu, Sz-Jie; Chen, Bang-Yuan; Huang, Hsiao-Wen; Wang, Chung-Yi

    2017-08-01

    The aim of this study was to investigate the microbial levels, physicochemical and antioxidant properties and polyphenol oxidase (PPO) and peroxidase (POD) activities as well as to conduct a sensory analysis of white grape juice treated with high-pressure processing (HPP) and thermal pasteurization (TP), over a period of 20 days of refrigerated storage. HPP treatment of 600 MPa and TP significantly reduced aerobic bacteria, coliform and yeast/mold counts. At day 20 of storage, HPP-600 juice displayed no significant differences compared with fresh juice in terms of physicochemical properties such as titratable acidity, pH and soluble solids, and retained less than 50% PPO and POD activities. Although significant differences were observed in the color, antioxidant contents and antioxidant capacity of HPP-treated juice, the extent of these differences was substantially lower than that in TP-treated juice, indicating that HPP treatment can better retain the quality of grape juice. Sensory testing showed no significant difference between HPP-treated juice and fresh juice, while TP reduced the acceptance of grape juice. This study shows that HPP treatment maintained the overall quality parameters of white grape juice, thus effectively extending the shelf life during refrigerated storage. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  11. Effect of substrate temperature on the optical parameters of thermally evaporated Ge-Se-Te thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Pankaj, E-mail: pks_phy@yahoo.co.i [Department of Physics, Jaypee University of Information Technology, Waknaghat, Solan, H.P. 173215 India (India); Katyal, S.C. [Department of Physics, Jaypee University of Information Technology, Waknaghat, Solan, H.P. 173215 India (India)

    2009-05-01

    Thin films of Ge{sub 10}Se{sub 90-x}Te{sub x} (x = 0, 10, 20, 30, 40, 50) glassy alloys were deposited at three substrate temperatures (303 K, 363 K and 423 K) using conventional thermal evaporation technique at base pressure of {approx} 10{sup -4} Pa. X-ray diffraction results show that films deposited at 303 K are of amorphous nature while films deposited at 363 K and 423 K are of polycrystalline nature. The optical parameters, refractive index and optical gap have been derived from the transmission spectra (using UV-Vis-NIR spectrophotometer) of the thin films in the spectral region 400-1500 nm. This has been observed that refractive index values remain almost constant while the optical gap is found to decrease considerably with the increase of substrate temperature. The decrease in optical gap is explained on the basis of change in nature of films, from amorphous to polycrystalline state, with the increase of substrate temperature. The optical gap has also been observed to decrease with the increase of Te content.

  12. Implicit Treatment of Technical Specification and Thermal Hydraulic Parameter Uncertainties in Gaussian Process Model to Estimate Safety Margin

    Directory of Open Access Journals (Sweden)

    Douglas A. Fynan

    2016-06-01

    Full Text Available The Gaussian process model (GPM is a flexible surrogate model that can be used for nonparametric regression for multivariate problems. A unique feature of the GPM is that a prediction variance is automatically provided with the regression function. In this paper, we estimate the safety margin of a nuclear power plant by performing regression on the output of best-estimate simulations of a large-break loss-of-coolant accident with sampling of safety system configuration, sequence timing, technical specifications, and thermal hydraulic parameter uncertainties. The key aspect of our approach is that the GPM regression is only performed on the dominant input variables, the safety injection flow rate and the delay time for AC powered pumps to start representing sequence timing uncertainty, providing a predictive model for the peak clad temperature during a reflood phase. Other uncertainties are interpreted as contributors to the measurement noise of the code output and are implicitly treated in the GPM in the noise variance term, providing local uncertainty bounds for the peak clad temperature. We discuss the applicability of the foregoing method to reduce the use of conservative assumptions in best estimate plus uncertainty (BEPU and Level 1 probabilistic safety assessment (PSA success criteria definitions while dealing with a large number of uncertainties.

  13. Influence of wood properties and technological parameters of processing on cutting power in milling of thermally modified beechwood

    Directory of Open Access Journals (Sweden)

    Mandić Marija

    2011-01-01

    Full Text Available The paper presents results of influence of thermal modification on cutting power required for milling wood processing. The experiment was conducted for the different treatment temperatures (170°C, 190°C and 210°C and different technological parameters of processing (feed and cutting depth. Cutting powers during milling were measured on four groups of beech wood samples, dimensions 35×16×400 mm, separately for heartwood and sapwood. The following mechanical and physical properties of the processed samples were tested: bending properties (modulus of rupture and modulus of elasticity, cross-sectional and tangential hardness, and air-dry density. The measuring device used for measuring, monitoring and displaying cutting power was developed at the Wood Machining Centre at the Faculty of Forestry in Belgrade. The results point out the differences in the powers required for processing heat-treated wood compared to untreated wood. The analysis shows that with the increase in treatment temperature, the required cutting powers decrease.

  14. Implicit treatment of technical specification and thermal hydraulic parameter uncertainties in Gaussian process model to estimate safety margin

    Energy Technology Data Exchange (ETDEWEB)

    Fynan, Douglas A.; Ahn, Kwang Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-06-15

    The Gaussian process model (GPM) is a flexible surrogate model that can be used for nonparametric regression for multivariate problems. A unique feature of the GPM is that a prediction variance is automatically provided with the regression function. In this paper, we estimate the safety margin of a nuclear power plant by performing regression on the output of best-estimate simulations of a large-break loss-of-coolant accident with sampling of safety system configuration, sequence timing, technical specifications, and thermal hydraulic parameter uncertainties. The key aspect of our approach is that the GPM regression is only performed on the dominant input variables, the safety injection flow rate and the delay time for AC powered pumps to start representing sequence timing uncertainty, providing a predictive model for the peak clad temperature during a reflood phase. Other uncertainties are interpreted as contributors to the measurement noise of the code output and are implicitly treated in the GPM in the noise variance term, providing local uncertainty bounds for the peak clad temperature. We discuss the applicability of the foregoing method to reduce the use of conservative assumptions in best estimate plus uncertainty (BEPU) and Level 1 probabilistic safety assessment (PSA) success criteria definitions while dealing with a large number of uncertainties.

  15. Comparison of the dynamism of the cardial rate by different kind of the Aerobic dynamic kickbox and Aero-kickboxing

    OpenAIRE

    Matoušková, Lucie

    2007-01-01

    Title: Comparison of heart rate dynamics In Aerobic Dynamic K.ickboxing and Aero-kickboxing Goal: Assessment of heart rate dynamics In Aerobic Dynamic K.ickboxing and Aero- K.ickboxing Method: For evaluation of relations connected to performance of cardiovascular system of respective individuals questionnaires were used. During selected classes of Aerobic Dynamic K.ickboxing and Aero-kickboxing I have measured heart rate using sport testers. Collected data were analysed and graphically evalua...

  16. Dynamic behavior of aero-engine rotor with fusing design suffering blade off

    Directory of Open Access Journals (Sweden)

    Cun WANG

    2017-06-01

    Full Text Available Fan blade off (FBO from a running turbofan rotor will introduce sudden unbalance into the dynamical system, which will lead to the rub-impact, the asymmetry of rotor and a series of interesting dynamic behavior. The paper first presents a theoretical study on the response excited by sudden unbalance. The results reveal that the reaction force of the bearing located near the fan could always reach a very high value which may lead to the crush of ball, journal sticking, high stress on the other components and some other failures to endanger the safety of engine in FBO event. Therefore, the dynamic influence of a safety design named “fusing” is investigated by mechanism analysis. Meantime, an explicit FBO model is established to simulate the FBO event, and evaluate the effectiveness and potential dynamic influence of fusing design. The results show that the fusing design could reduce the vibration amplitude of rotor, the reaction force on most bearings and loads on mounts, but the sudden change of support stiffness induced by fusing could produce an impact effect which will couple with the influence of sudden unbalance. Therefore, the implementation of the design should be considered carefully with optimized parameters in actual aero-engine.

  17. Nonlocal sparse model with adaptive structural clustering for feature extraction of aero-engine bearings

    Science.gov (United States)

    Zhang, Han; Chen, Xuefeng; Du, Zhaohui; Li, Xiang; Yan, Ruqiang

    2016-04-01

    Fault information of aero-engine bearings presents two particular phenomena, i.e., waveform distortion and impulsive feature frequency band dispersion, which leads to a challenging problem for current techniques of bearing fault diagnosis. Moreover, although many progresses of sparse representation theory have been made in feature extraction of fault information, the theory also confronts inevitable performance degradation due to the fact that relatively weak fault information has not sufficiently prominent and sparse representations. Therefore, a novel nonlocal sparse model (coined NLSM) and its algorithm framework has been proposed in this paper, which goes beyond simple sparsity by introducing more intrinsic structures of feature information. This work adequately exploits the underlying prior information that feature information exhibits nonlocal self-similarity through clustering similar signal fragments and stacking them together into groups. Within this framework, the prior information is transformed into a regularization term and a sparse optimization problem, which could be solved through block coordinate descent method (BCD), is formulated. Additionally, the adaptive structural clustering sparse dictionary learning technique, which utilizes k-Nearest-Neighbor (kNN) clustering and principal component analysis (PCA) learning, is adopted to further enable sufficient sparsity of feature information. Moreover, the selection rule of regularization parameter and computational complexity are described in detail. The performance of the proposed framework is evaluated through numerical experiment and its superiority with respect to the state-of-the-art method in the field is demonstrated through the vibration signals of experimental rig of aircraft engine bearings.

  18. The DAN-AERO MW experiments. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard Madsen, H.; Bak, C.; Schmidt Paulsen, U.; Gaunaa, M. (Risoe DTU, Roskilde (Denmark)); Fuglsang, P. (LM Glasfiber, Kolding (Denmark)); Romblad, J.; Olesen, N.A. (Vestas Wind Systems, Ringkoebing (Denmark)); Enevoldsen, P.; Laursen, J. (Siemens Wind Power, Ballerup (Denmark)); Jensen, Leo (DONG Energy, Fredericia (Denmark))

    2010-09-15

    This report describes the DAN-AERO MW experiments carried out within a collaborative, three years research project between Risoe DTU and the industrial partners LM Glasfiber, Siemens Wind Power, Vestas Wind Systems A/S and the utility company DONG Energy. The main objective of the project was to establish an experimental data base which can provide new insight into a number of fundamental aerodynamic and aero-acoustic issues, important for the design and operation of MW size turbines. The most important issue is the difference between airfoil characteristics measured under 2D, steady conditions in a wind tunnel and the unsteady 3D flow conditions on a rotor. The different transition characteristics might explain some of the differences between the 2D and 3D airfoil data and the experiments have been set up to provide data on this subject. The overall experimental approach has been to carry out a number of coordinated, innovative measurements on full scale MW size rotors as well as on airfoils for MW size turbines in wind tunnels. Shear and turbulence inflow characteristics were measured on a Siemens 3.6 MW turbine with a five hole pitot tube. Pressure and turbulent inflow characteristics were measured on a 2MW NM80 turbine with an 80 m rotor. One of the LM38.8 m blades on the rotor was replaced with a new LM38.8 m blade where instruments for surface pressure measurements at four radial sections were build into the blade during the blade production process. Additionally, the outmost section on the blade was further instrumented with around 50 microphones for high frequency surface pressure measurements. The surface pressure measurements have been correlated with inflow measurements from four five hole pitot tubes and two sensors for measuring the high frequency (50 Hz to10 kHz) contents of the inflow turbulence. In parallel, 2D wind tunnel measurements on common airfoils for wind turbine applications have been conducted in three different wind tunnels at Delft

  19. Thermal Orbital Environmental Parameter Study on the Propulsive Small Expendable Deployer System (ProSEDS) Using Earth Radiation Budget Experiment (ERBE) Data

    Science.gov (United States)

    Sharp, John R.; McConnaughey, Paul K. (Technical Monitor)

    2002-01-01

    The natural thermal environmental parameters used on the Space Station Program (SSP 30425) were generated by the Space Environmental Effects Branch at NASA's Marshall Space Flight Center (MSFC) utilizing extensive data from the Earth Radiation Budget Experiment (ERBE), a series of satellites which measured low earth orbit (LEO) albedo and outgoing long-wave radiation. Later, this temporal data was presented as a function of averaging times and orbital inclination for use by thermal engineers in NASA Technical Memorandum TM 4527. The data was not presented in a fashion readily usable by thermal engineering modeling tools and required knowledge of the thermal time constants and infrared versus solar spectrum sensitivity of the hardware being analyzed to be used properly. Another TM was recently issued as a guideline for utilizing these environments (NASA/TM-2001-211221) with more insight into the utilization by thermal analysts. This paper gives a top-level overview of the environmental parameters presented in the TM and a study of the effects of implementing these environments on an ongoing MSFC project, the Propulsive Small Expendable Deployer System (ProSEDS), compared to conventional orbital parameters that had been historically used.

  20. Calculation of the Thermal Parameters and Change in The Share of Emissions of Harmful Substances During Combustion of Water-Fuel Emulsion

    Science.gov (United States)

    Toropov, S. Y.; Berg, V. I.; Petryakov, V. A.; Mostovaya, N. A.

    2016-10-01

    The article investigates the possibility to improve efficiency and ecological compatibility of fuel oil with use water-fuel emulsion. The calculation of the thermal parameters and change in the share of emissions of harmful substances during combustion of water-fuel emulsion and optimal water content in water-fuel emulsion.

  1. Dynamic performance of an aero-assist spacecraft - AFE

    Science.gov (United States)

    Chang, Ho-Pen; French, Raymond A.

    1992-01-01

    Dynamic performance of the Aero-assist Flight Experiment (AFE) spacecraft was investigated using a high-fidelity 6-DOF simulation model. Baseline guidance logic, control logic, and a strapdown navigation system to be used on the AFE spacecraft are also modeled in the 6-DOF simulation. During the AFE mission, uncertainties in the environment and the spacecraft are described by an error space which includes both correlated and uncorrelated error sources. The principal error sources modeled in this study include navigation errors, initial state vector errors, atmospheric variations, aerodynamic uncertainties, center-of-gravity off-sets, and weight uncertainties. The impact of the perturbations on the spacecraft performance is investigated using Monte Carlo repetitive statistical techniques. During the Solid Rocket Motor (SRM) deorbit phase, a target flight path angle of -4.76 deg at entry interface (EI) offers very high probability of avoiding SRM casing skip-out from the atmosphere. Generally speaking, the baseline designs of the guidance, navigation, and control systems satisfy most of the science and mission requirements.

  2. Commercial Modular Aero-Propulsion System Simulation 40k

    Science.gov (United States)

    Guo, Ten-Huei; Lavelle, Thomas; Litt, Jonathan; Csank, Jeffrey; May, Ryan

    2011-01-01

    The Commercial Modular Aero-Propulsion System Simulation 40k (CMAPSS40k) software package is a nonlinear dynamic simulation of a 40,000-pound (approximately equals 178-kN) thrust class commercial turbofan engine, written in the MATLAB/Simulink environment. The model has been tuned to capture the behavior of flight test data, and is capable of running at any point in the flight envelope [up to 40,000 ft (approximately equals 12,200 m) and Mach 0.8]. In addition to the open-loop engine, the simulation includes a controller whose architecture is representative of that found in industry. C-MAPSS40k fills the need for an easy-to-use, realistic, transient simulation of a medium-size commercial turbofan engine with a representative controller. It is a detailed component level model (CLM) written in the industry-standard graphical MATLAB/Simulink environment to allow for easy modification and portability. At the time of this reporting, no other such model exists in the public domain.

  3. Interconnection of thermal parameters, microstructure and mechanical properties in directionally solidified Sn–Sb lead-free solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Marcelino; Costa, Thiago [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Rocha, Otávio [Federal Institute of Education, Science and Technology of Pará — IFPA, 66093-020 Belém, PA (Brazil); Spinelli, José E. [Department of Materials Engineering, Federal University of São Carlos — UFSCar, 13565-905 São Carlos, SP (Brazil); Cheung, Noé, E-mail: cheung@fem.unicamp.br [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil); Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas — UNICAMP, 13083-860 Campinas, SP (Brazil)

    2015-08-15

    Considerable effort is being made to develop lead-free solders for assembling in environmental-conscious electronics, due to the inherent toxicity of Pb. The search for substitute alloys of Pb–Sn solders has increased in order to comply with different soldering purposes. The solder must not only meet the expected levels of electrical performance but may also have appropriate mechanical strength, with the absence of cracks in the solder joints. The Sn–Sb alloy system has a range of compositions that can be potentially included in the class of high temperature solders. This study aims to establish interrelations of solidification thermal parameters, microstructure and mechanical properties of Sn–Sb alloys (2 wt.%Sb and 5.5 wt.%Sb) samples, which were directionally solidified under cooling rates similar to those of reflow procedures in industrial practice. A complete high-cooling rate cellular growth is shown to be associated with the Sn–2.0 wt.%Sb alloy and a reverse dendrite-to-cell transition is observed for the Sn–5.5 wt.%Sb alloy. Strength and ductility of the Sn–2.0 wt.%Sb alloy are shown not to be affected by the cellular spacing. On the other hand, a considerable variation in these properties is associated with the cellular region of the Sn–5.5 wt.%Sb alloy casting. - Graphical abstract: Display Omitted - Highlights: • The microstructure of the Sn–2 wt.%Sb alloy is characterized by high-cooling rates cells. • Reverse dendrite > cell transition occurs for Sn–5.5 wt.%Sb alloy: cells prevail for cooling rates > 1.2 K/s. • Sn–5.5 wt.%Sb alloy: the dendritic region occurs for cooling rates < 0.9 K/s. • Sn–5.5 wt.%Sb alloy: tensile properties are improved with decreasing cellular spacing.

  4. Estimation of lifespan and economy parameters of steam-turbine power units in thermal power plants using varying regimes

    Science.gov (United States)

    Aminov, R. Z.; Shkret, A. F.; Garievskii, M. V.

    2016-08-01

    The use of potent power units in thermal and nuclear power plants in order to regulate the loads results in intense wear of power generating equipment and reduction in cost efficiency of their operation. We review the methodology of a quantitative assessment of the lifespan and wear of steam-turbine power units and estimate the effect of various operation regimes upon their efficiency. To assess the power units' equipment wear, we suggest using the concept of a turbine's equivalent lifespan. We give calculation formulae and an example of calculation of the lifespan of a steam-turbine power unit for supercritical parameters of steam for different options of its loading. The equivalent lifespan exceeds the turbine's assigned lifespan only provided daily shutdown of the power unit during the night off-peak time. We obtained the engineering and economical indices of the power unit operation for different loading regulation options in daily and weekly diagrams. We proved the change in the prime cost of electric power depending on the operation regimes and annual daily number of unloading (non-use) of the power unit's installed capacity. According to the calculation results, the prime cost of electric power for the assumed initial data varies from 11.3 cents/(kW h) in the basic regime of power unit operation (with an equivalent operation time of 166700 hours) to 15.5 cents/(kW h) in the regime with night and holiday shutdowns. The reduction of using the installed capacity of power unit at varying regimes from 3.5 to 11.9 hours per day can increase the prime cost of energy from 4.2 to 37.4%. Furthermore, repair and maintenance costs grow by 4.5% and by 3 times, respectively, in comparison with the basic regime. These results indicate the need to create special maneuverable equipment for working in the varying section of the electric load diagram.

  5. Processing Parameter Effects and Thermal Properties of Y2Si2O7 Nanostructured Environmental Barrier Coatings Synthesized by Solution Precursor Induction Plasma Spraying

    Science.gov (United States)

    Darthout, Émilien; Laduye, Guillaume; Gitzhofer, François

    2016-09-01

    The solution precursor plasma spray process, in which a solution of metal salts is axially injected into an induction thermal plasma, is suitable for deposition of nanostructured environmental barrier coatings. The effects of main processing parameters, namely the solution precursor concentration, spraying distance, reactor pressure, and atomization gas flow rate, have been analyzed using D-optimal design of experiments regarding the deposition rate and coating porosity responses. Among these four parameters, the solution precursor concentration had the greatest influent on the coating structure, followed by the spraying distance and reactor pressure, and finally the atomization gas flow rate with a small contribution. It is pointed out that the species that impact on the substrate are agglomerates of nanoparticles. The equivalent thermal conductivity of selected coatings was computed from experimental temperature evolution curves obtained by laser flash thermal diffusivity analysis, using two methods: a multilayer finite-element model with optimization, and a multilayer thermal diffusion model. The results of the two models agree, with coatings exhibiting low thermal conductivity between 0.7 and 1 W/(m K) at 800 °C.

  6. Processing Parameter Effects and Thermal Properties of Y2Si2O7 Nanostructured Environmental Barrier Coatings Synthesized by Solution Precursor Induction Plasma Spraying

    Science.gov (United States)

    Darthout, Émilien; Laduye, Guillaume; Gitzhofer, François

    2016-10-01

    The solution precursor plasma spray process, in which a solution of metal salts is axially injected into an induction thermal plasma, is suitable for deposition of nanostructured environmental barrier coatings. The effects of main processing parameters, namely the solution precursor concentration, spraying distance, reactor pressure, and atomization gas flow rate, have been analyzed using D-optimal design of experiments regarding the deposition rate and coating porosity responses. Among these four parameters, the solution precursor concentration had the greatest influent on the coating structure, followed by the spraying distance and reactor pressure, and finally the atomization gas flow rate with a small contribution. It is pointed out that the species that impact on the substrate are agglomerates of nanoparticles. The equivalent thermal conductivity of selected coatings was computed from experimental temperature evolution curves obtained by laser flash thermal diffusivity analysis, using two methods: a multilayer finite-element model with optimization, and a multilayer thermal diffusion model. The results of the two models agree, with coatings exhibiting low thermal conductivity between 0.7 and 1 W/(m K) at 800 °C.

  7. Fault Diagnosis of Demountable Disk-Drum Aero-Engine Rotor Using Customized Multiwavelet Method

    Directory of Open Access Journals (Sweden)

    Jinglong Chen

    2015-10-01

    Full Text Available The demountable disk-drum aero-engine rotor is an important piece of equipment that greatly impacts the safe operation of aircraft. However, assembly looseness or crack fault has led to several unscheduled breakdowns and serious accidents. Thus, condition monitoring and fault diagnosis technique are required for identifying abnormal conditions. Customized ensemble multiwavelet method for aero-engine rotor condition identification, using measured vibration data, is developed in this paper. First, customized multiwavelet basis function with strong adaptivity is constructed via symmetric multiwavelet lifting scheme. Then vibration signal is processed by customized ensemble multiwavelet transform. Next, normalized information entropy of multiwavelet decomposition coefficients is computed to directly reflect and evaluate the condition. The proposed approach is first applied to fault detection of an experimental aero-engine rotor. Finally, the proposed approach is used in an engineering application, where it successfully identified the crack fault of a demountable disk-drum aero-engine rotor. The results show that the proposed method possesses excellent performance in fault detection of aero-engine rotor. Moreover, the robustness of the multiwavelet method against noise is also tested and verified by simulation and field experiments.

  8. Parameter variation effects on temperature elevation in a steady-state, one-dimensional thermal model for millimeter wave exposure of one- and three-layer human tissue

    Energy Technology Data Exchange (ETDEWEB)

    Kanezaki, Akio; Shirai, Hiroshi [Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551 (Japan); Hirata, Akimasa; Watanabe, Soichi, E-mail: ahirata@nitech.ac.j [National Institute of Information and Communications Technology, 4-2-1 Nukuikitamachi, Koganei-shi, Tokyo 184-8795 (Japan)

    2010-08-21

    The present study describes theoretical parametric analysis of the steady-state temperature elevation in one-dimensional three-layer (skin, fat and muscle) and one-layer (skin only) models due to millimeter-wave exposure. The motivation of this fundamental investigation is that some variability of warmth sensation in the human skin has been reported. An analytical solution for a bioheat equation was derived by using the Laplace transform for the one-dimensional human models. Approximate expressions were obtained to investigate the dependence of temperature elevation on different thermal and tissue thickness parameters. It was shown that the temperature elevation on the body surface decreases monotonically with the blood perfusion rate, heat conductivity and heat transfer from the body to air. Also revealed were the conditions where maximum and minimum surface temperature elevations were observed for different thermal and tissue thickness parameters. The surface temperature elevation in the three-layer model is 1.3-2.8 times greater than that in the one-layer model. The main reason for this difference is attributed to the adiabatic nature of the fat layer. By considering the variation range of thermal and tissue thickness parameters which causes the maximum and minimum temperature elevations, the dominant parameter influencing the surface temperature elevation was found to be the heat transfer coefficient between the body surface and air.

  9. Cross-Laboratory Comparative Study of the Impact of Experimental and Regression Methodologies on Salmonella Thermal Inactivation Parameters in Ground Beef.

    Science.gov (United States)

    Hildebrandt, Ian M; Marks, Bradley P; Juneja, Vijay K; Osoria, Marangeli; Hall, Nicole O; Ryser, Elliot T

    2016-07-01

    Isothermal inactivation studies are commonly used to quantify thermal inactivation kinetics of bacteria. Meta-analyses and comparisons utilizing results from multiple sources have revealed large variations in reported thermal resistance parameters for Salmonella, even when in similar food materials. Different laboratory or regression methodologies likely are the source of methodology-specific artifacts influencing the estimated parameters; however, such effects have not been quantified. The objective of this study was to evaluate the effects of laboratory and regression methodologies on thermal inactivation data generation, interpretation, modeling, and inherent error, based on data generated in two independent laboratories. The overall experimental design consisted of a cross-laboratory comparison using two independent laboratories (Michigan State University and U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center [ERRC] laboratories), both conducting isothermal Salmonella inactivation studies (55, 60, 62°C) in ground beef, and each using two methodologies reported in prior studies. Two primary models (log-linear and Weibull) with one secondary model (Bigelow) were fitted to the resultant data using three regression methodologies (two two-step regressions and a one-step regression). Results indicated that laboratory methodology impacted the estimated D60°C- and z-values (α = 0.05), with the ERRC methodology yielding parameter estimates ∼25% larger than the Michigan State University methodology, regardless of the laboratory. Regression methodology also impacted the model and parameter error estimates. Two-step regressions yielded root mean square error values on average 40% larger than the one-step regressions. The Akaike Information Criterion indicated the Weibull as the more correct model in most cases; however, caution should be used to confirm model robustness in application to real-world data. Overall, the

  10. 75 FR 904 - Airworthiness Directives; PIAGGIO AERO INDUSTRIES S.p.A Model PIAGGIO P-180 Airplanes

    Science.gov (United States)

    2010-01-07

    ... INDUSTRIES S.p.A Model PIAGGIO P-180 Airplanes AGENCY: Federal Aviation Administration (FAA), Department of... Directive (AD) 2009-21-08, which applies to PIAGGIO AERO INDUSTRIES S.p.A. (Piaggio) Model PIAGGIO P-180...: Service information title Page(s) Revision Date PIAGGIO AERO INDUSTRIES S.p.A. 1 through 9........ Rev....

  11. SFC Optimization for Aero Engine Based on Hybrid GA-SQP Method

    Science.gov (United States)

    Li, Jie; Fan, Ding; Sreeram, Victor

    2013-12-01

    This study focuses on on-line specific fuel consumption (SFC) optimization of aero engines. For solving this optimization problem, a nonlinear pneumatic and thermodynamics model of the aero engine is built and a hybrid optimization technique which is formed by combining the genetic algorithm (GA) and the sequential quadratic programming (SQP) is presented. The ability of standard GA and standard SQP in solving this type of problem is investigated. It has been found that, although the SQP is fast, very little SFC reductions can be obtained. The GA is able to solve the problem well but a lot of computational time is needed. The presented hybrid GA-SQP gives a good SFC optimization effect and saves 76.6% computational time when compared to the standard GA. It has been shown that the hybrid GA-SQP is a more effective and higher real-time method for SFC on-line optimization of the aero engine.

  12. Frequency-domain Model Matching PID Controller Design for Aero-engine

    Science.gov (United States)

    Liu, Nan; Huang, Jinquan; Lu, Feng

    2014-12-01

    The nonlinear model of aero-engine was linearized at multiple operation points by using frequency response method. The validation results indicate high accuracy of static and dynamic characteristics of the linear models. The improved PID tuning method of frequency-domain model matching was proposed with the system stability condition considered. The proposed method was applied to the design of PID controller of the high pressure rotor speed control in the flight envelope, and the control effects were evaluated by the nonlinear model. Simulation results show that the system had quick dynamic response with zero overshoot and zero steadystate error. Furthermore, a PID-fuzzy switching control scheme for aero-engine was designed, and the fuzzy switching system stability was proved. Simulations were studied to validate the applicability of the multiple PIDs fuzzy switching controller for aero-engine with wide range dynamics.

  13. Aero-MINE (Motionless INtegrated Energy) for Distributed Scalable Wind Power.

    Energy Technology Data Exchange (ETDEWEB)

    Houchens, Brent C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Blaylock, Myra L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-06-01

    The proposed Aero-MINE technology will extract energy from wind without any exterior moving parts. Aero-MINEs can be integrated into buildings or function stand-alone, and are scalable. This gives them advantages similar to solar panels, but with the added benefit of operation in cloudy or dark conditions. Furthermore, compared to solar panels, Aero-MINEs can be manufactured at lower cost and with less environmental impact. Power generation is isolated internally by the pneumatic transmission of air and the outlet air-jet nozzles amplify the effectiveness. Multiple units can be connected to one centrally located electric generator. Aero-MINEs are ideal for the built-environment, with numerous possible configurations ranging from architectural integration to modular bolt-on products. Traditional wind turbines suffer from many fundamental challenges. The fast-moving blades produce significant aero-acoustic noise, visual disturbances, light-induced flickering and impose wildlife mortality risks. The conversion of massive mechanical torque to electricity is a challenge for gears, generators and power conversion electronics. In addition, the installation, operation and maintenance of wind turbines is required at significant height. Furthermore, wind farms are often in remote locations far from dense regions of electricity customers. These technical and logistical challenges add significantly to the cost of the electricity produced by utility-scale wind farms. In contrast, distributed wind energy eliminates many of the logistical challenges. However, solutions such as micro-turbines produce relatively small amounts of energy due to the reduction in swept area and still suffer from the motion-related disadvantages of utility-scale turbines. Aero-MINEs combine the best features of distributed generation, while eliminating the disadvantages.

  14. Thermal expansion, heat capacity and Grüneisen parameter of iridium phosphide Ir2P from quasi-harmonic Debye model

    Science.gov (United States)

    Liu, Z. J.; Song, T.; Sun, X. W.; Ma, Q.; Wang, T.; Guo, Y.

    2017-03-01

    Thermal expansion coefficient, heat capacity, and Grüneisen parameter of iridium phosphide Ir2P are reported by means of quasi-harmonic Debye model for the first time in the current study. This model combines with first-principles calculations within generalized gradient approximation using pseudopotentials and a plane-wave basis in the framework of density functional theory, and it takes into account the phononic effects within the quasi-harmonic approximation. The Debye temperature as a function of volume, the Grüneisen parameter, thermal expansion coefficient, constant-volume and constant-pressure heat capacities, and entropy on the temperature T are also successfully obtained. All the thermodynamic properties of Ir2P in the whole pressure range from 0 to 100 GPa and temperature range from 0 to 3000 K are summarized and discussed in detail.

  15. Modeling of thermal lensing in a [1 1 1]-cut Nd:YAG rod with temperature-dependent parameters and different pumping profiles

    Science.gov (United States)

    Bričkus, D.; Dement'ev, A. S.

    2017-05-01

    Temperature dependences of the thermo-optical coefficients of YAG crystals are often neglected when thermal lensing in laser rods is investigated, though their influence is very significant. It is especially significant for transversally non-uniform thermal loading. An analytical solution of the heat transfer equation with only the radial heat flow is found in the integral form, which is very convenient for numerical simulations. Uniform, top-hat, parabolic, Gaussian, super-Gaussian and annular heat source distributions are used in the calculations. The generalization of the thermally-induced refractive index change for long enough [1 1 1]-cut YAG rods to the case of temperature-dependent YAG parameters is developed and applied to the calculation of the corresponding optical path differences. Different definitions of the optical power of the aberrated thermal lens (TL) are discussed in detail. It is shown that for each of the heat source distributions, the temperature dependences of the YAG parameters significantly increase (1.5-1.8 times) the paraxial optical power of the induced TL.

  16. EFFECT OF STRUCTURAL PARAMETERS ON THE THERMAL STRESS OF A NiFe2O4-BASED CERMET INERT ANODE IN ALUMINUM ELECTROLYSIS

    Institute of Scientific and Technical Information of China (English)

    J. Li; Z.G. Wang; Y. Q. Lai; Y.Y. Wu; S.L. Ye

    2007-01-01

    Inert anode has been a hot issue in the aluminum industry for many decades. With the help of FEA (finite element analysis) software ANSYS, a model was developed to simulate the thermal stress distribution working condition of an inert anode. To reduce its thermal stress,the effect of some parameters on the thermal stress distribution was investigated, including the anode height, the anode radius, the hole depth, the hole radius, and the radius of inner chamfer and outer chamfer. The results showed that in the actual working condition of an inert anode, there existed a large axial tensile stress near the tangent interface between the anode and bath, which was the major cause of anode breaking. Increasing the anode height and reducing the hole depth properly seemed to be beneficial for the stress distribution. With the increase of anode radius, the stress distribution became better first and then deteriorated,the reasonable value was between 0.045 to 0.06m. The hole radius had a significant effect on the stress and a smaller radius would reduce the thermal stress. The effect of the radius of the inner chamfer and the outer chamfer was less than other parameters.

  17. Finite element analysis of welding residual stress of aero engine blisk by controlling heat input

    Institute of Scientific and Technical Information of China (English)

    Zhang Xueqiu; Yang Jianguo; Chen Xuhui; Fang Hongyuan; Qu Shen; Wang Licheng

    2009-01-01

    In order to improve aero engine performance, it is necessary to reduce the welding residual stress of aero engine blisk. In this paper, finite element method was employed to simulate electron beam welding process of blisk, in accordance with the deducing formula (p = kh) , the heat input is changed with the weld depth to control welding residual stress of blisk. The calculation results show that welding residual stress of blisk can be controlled effectively by reducing the heat input on the conditions of meeting the demand of weld penetration and guaranteeing the welding quality, a new theoretical method and some numerical data are provided for controlling welding residual stress of blisk.

  18. Thermal comfort

    CSIR Research Space (South Africa)

    Osburn, L

    2010-01-01

    Full Text Available Thermal comfort is influenced by environmental parameters as well as other influences including asymmetric heating and cooling conditions. Additionally, some aspects of thermal comfort may be exploited so as to enable a building to operate within a...

  19. Environmental parameters of the Tennessee River in Alabama. 2: Physical, chemical, and biological parameters. [biological and chemical effects of thermal pollution from nuclear power plants on water quality

    Science.gov (United States)

    Rosing, L. M.

    1976-01-01

    Physical, chemical and biological water quality data from five sites in the Tennessee River, two in Guntersville Reservoir and three in Wheeler Reservoir were correlated with climatological data for three annual cycles. Two of the annual cycles are for the years prior to the Browns Ferry Nuclear Power Plant operations and one is for the first 14 months of Plant operations. A comparison of the results of the annual cycles indicates that two distinct physical conditions in the reservoirs occur, one during the warm months when the reservoirs are at capacity and one during the colder winter months when the reservoirs have been drawn-down for water storage during the rainy months and for weed control. The wide variations of physical and chemical parameters to which the biological organisms are subjected on an annual basis control the biological organisms and their population levels. A comparison of the parameters of the site below the Power plant indicates that the heated effluent from the plant operating with two of the three reactors has not had any effect on the organisms at this site. Recommendations given include the development of prediction mathematical models (statistical analysis) for the physical and chemical parameters under specific climatological conditions which affect biological organisms. Tabulated data of chemical analysis of water and organism populations studied is given.

  20. Effects of laser processing parameters on solidification microstructures of ternary Al_2O_3/YAG/ZrO_2 eutectic in situ composite and its thermal property

    Institute of Scientific and Technical Information of China (English)

    SU Hai-jun; ZHANG Jun; LIU Lin; FU Heng-zhi

    2009-01-01

    Rapid surface resolidification with a high powered CO_2-laser was performed in preparing directionally solidified Al_2O_3/YAG/ZrO_2 ternary eutectic ceramic in situ composite.The effects of laser processing parameters on the solidification microstructure characteristics and thermal properties were studied by scanning electron microscopy (SEM),energy dispersive spectroscopy (EDS),X-ray diffractometry (XRD) and synthetically thermal analysis (STA).Detailed investigations of the influence of laser power and scanning rate on the preparation and microstructural parameters of the ternary eutectic were presented.Moreover,the eutectic phase separation rule at high temperature was discussed.The results indicate that solidification microstructure of the ternary eutectic composite is greatly influenced by the laser processing parameters.The synthetically thermal analysis shows that the eutectic temperature of ternary Al_2O_3/YAG/ZrO_2 composite is 1 738 ℃,well matching the phase diagram of Al_2O_3-Y_2O_3-ZrO_2.

  1. Microscopic studies of the influence of main exposure time on parameters of flexographic printing plate produced by digital thermal method.

    Science.gov (United States)

    Harri, Liliya

    2009-10-01

    The digital thermal technology of producing flexographic printing plates from photopolymer plates is one of the newest technologies. This technology allows to develop flexographic plates without the use of any solvent. The process of producing flexographic printing plates by the digital thermal method consists of several main stages: back exposure, laser exposure, main exposure, thermal development, post exposure, and light finishing. The studies carried out with the use of optical stereoscopic microscopy allowed to determine the effect of time of main exposure to ultraviolet radiation on the dot area, diameter, and edge factor of halftone dots reproduced on flexographic printing plate produced by the digital thermal method, as well as on the quality of reproducing the surface and on the profiles of free-standing printing microelements. The results of the microscopic studies performed have allowed to define the criteria of establishing optimum time of main exposure of photopolymer plates used in the digital thermal technology of producing flexographic printing plates. A precise definition of the criteria for determining the optimum time of main exposure will enable to reduce the time-consuming control tests and to eliminate errors in both the process of manufacturing flexographic printing plates and in the printing process carried out with the use of such plates.

  2. System Aero-Accelator for the purification of biodegradable effluents; Sistema aero-accelator para la depuracion de efluentes biodegradables (I)

    Energy Technology Data Exchange (ETDEWEB)

    Bosque Hernandez, J. L. del; Martin Sanchez, J. L. [Universidad de Salamanca (Spain)

    2000-07-01

    The contamination of the waters is one of the factors that contributes to the deterioration of our environment and since it is a very limited one its treatment descontaminant it is one of the politic's main objectives and environmental administration at all the levels, being spread to the total purification of the generated residual effluents. To reach this objective, big technological efforts are required that allow next to the creation of new processes, the adaptation of the processes existent depuratives, increasing the effectiveness of the same ones. One of the techniques of purification of possible recovery is the Compact System of active mires Aero-Accelator. Presently work is designed and it builds a plant pilot with Aero-Accelator geometry to study its behavior in the treatment of effluents of urban type with different loads pollutants. (Author) 16 refs.

  3. General catalogue of products and services - geology. AERO data base; 2. ed; Catalogo geral de produtos e servicos - geologia. Base de dados AERO

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The catalogue in the second edition aims at presenting to the user a general idea on the aerogeophysical projects of Brazil database (AERO) which belongs to SIGA (Brazilian geological information system). The 151 documents (projects) are listed as follows: 52 projects performed by CPRM/DNPM - Departamento Nacional de Producao Mineral; 33 projects performed by CNEN - Commissao Nacional de Energia Nuclear and NUCLEBRAS; 7 projects executed by State government and private companies; and 59 projects executed for PETROBRAS 159 figs., 5 tabs.

  4. Fractionation and physicochemical characterization of lignin from waste jute bags: Effect of process parameters on yield and thermal degradation.

    Science.gov (United States)

    Ahuja, Dheeraj; Kaushik, Anupama; Chauhan, Ghanshyam S

    2017-04-01

    In this work lignin was extracted from waste jute bags using soda cooking method and effect of varying alkali concentration and pH on yield, purity, structure and thermal degradation of lignin were studied. The Lignin yield, chemical composition and purity were assessed using TAPPI method and UV-vis spectroscopy. Yield and purity of lignin ranged from 27 to 58% and 50-94%, respectively for all the samples and was maximum for 8% alkali concentration and at pH 2 giving higher thermal stability. Chemical structure, thermal stability and elementary analysis of lignin were studied using FTIR, (H)NMR, thermo gravimetric analysis (TGA) and Elemental analyzer. FTIR and (H)NMR results showed that core structure of lignin starts breaking beyond 10% alkali concentration. S/G ratio shows the dominance of Syringyl unit over guaiacyl unit. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Advanced Aero-Propulsive Mid-Lift-to-Drag Ratio Entry Vehicle for Future Exploration Missions

    Science.gov (United States)

    Campbell, C. H.; Stosaric, R. R; Cerimele, C. J.; Wong, K. A.; Valle, G. D.; Garcia, J. A.; Melton, J. E.; Munk, M. M.; Blades, E.; Kuruvila, G.; hide

    2012-01-01

    vehicle stage return, thus making ideas reality. These paradigm shifts include the technology maturation of advanced flexible thermal protection materials onto mid lift-to-drag ratio entry vehicles, the development of integrated supersonic aero-propulsive maneuvering, and the implementation of advanced asymmetric launch shrouds. These paradigms have significant overlap with launch vehicle stage return already being developed by the Air Force and several commercial space efforts. Completing the realization of these combined paradigms holds the key to a high-performing entry vehicle system capability that fully leverages multiple technology benefits to accomplish NASA's Exploration missions to atmospheric planetary destinations.

  6. Do Lumped-Parameter Models Provide the Correct Geometrical Damping?

    DEFF Research Database (Denmark)

    Andersen, Lars

    2007-01-01

    This paper concerns the formulation of lumped-parameter models for rigid footings on homogenous or stratified soil with focus on the horizontal sliding and rocking. Such models only contain a few degrees of freedom, which makes them ideal for inclusion in aero-elastic codes for wind turbines...

  7. Do Lumped-Parameter Models Provide the Correct Geometrical Damping?

    DEFF Research Database (Denmark)

    Andersen, Lars

    2007-01-01

    This paper concerns the formulation of lumped-parameter models for rigid footings on homogenous or stratified soil with focus on the horizontal sliding and rocking. Such models only contain a few degrees of freedom, which makes them ideal for inclusion in aero-elastic codes for wind turbines...

  8. X-ray diffraction study of thermal parameters of Pd, Pd-Ag and Pd-Ag-Cu alloys as hydrogen purification membrane materials

    Science.gov (United States)

    Pati, Subhasis; Jat, Ram Avtar; Mukerjee, S. K.; Parida, S. C.

    2016-03-01

    High temperature X-ray diffraction measurements were carried out for pure palladium and palladium-rich alloys of compositions Pd0.77Ag0.23 and Pd0.77Ag0.10Cu0.13 in the temperature range of 298-1023 K at an interval of 50 K. The lattice parameters, coefficient of thermal expansion and X-ray Debye temperature of these materials were calculated as a function of temperature from the XRD data. The lattice parameter of Pd0.77Ag0.23 alloy was found to be higher than that of palladium, whereas the lattice parameter of Pd0.77Ag0.10Cu0.13 was found to be lower than that of palladium in the temperature range of investigation. Further, the lattice parameters of both the palladium alloys show negative deviation from Vegard's law and the deviation was found to increase with increase in temperature. The average value of coefficient of linear thermal expansion was found to follow the trend: αT (Pd)>αT (Pd0.77Ag0.23)>αT (Pd0.77Ag0.10Cu0.13). The X-ray Debye temperatures of Pd0.77Ag0.23 and Pd0.77Ag0.10Cu0.13 alloys were calculated and found to be 225±10 and 165±10 K, respectively.

  9. Combined high-pressure and thermal treatments for processing of tomato puree : evaluation of microbial inactivation and quality parameters

    NARCIS (Netherlands)

    Krebbers, B.; Matser, A.M.; Hoogerwerf, S.W.; Moezelaar, R.; Tomassen, M.M.M.; Berg, van den R.W.

    2003-01-01

    The effects of combined high-pressure thermal treatments on consistency, viscosity, colour, lycopene content, enzyme activity and micro-organisms were determined, and compared to conventional pasteurisation and sterilisation processes of tomato puree. High-pressure processing at ambient temperature

  10. Biological parameters and thermal requirements of the parasitoid Praon volucre (Hymenoptera: Braconidae) with Macrosiphum euphorbiae (Hemiptera: Aphididae) as host

    NARCIS (Netherlands)

    Conti, De B.F.; Bueno, V.H.P.; Sampaio, M.V.; Lenteren, van J.C.

    2011-01-01

    The effect of temperature on the biology of Praon volucre (Haliday, 1833) (Hymenoptera: Braconidae) in Macrosiphum euphorbiae (Thomas, 1878) (Hemiptera: Aphididae) hosts was studied and the thermal requirements of the parasitoid were determined. Experiments were carried out at 16, 19, 22, 25, and 28

  11. Large-scale variation of electron parameters from Quasi-Thermal Noise during WIND perigees in the Earth's magnetosphere

    Science.gov (United States)

    Issautier, Karine; Ongala-Edoumou, Samuel; Moncuquet, Michel

    2016-04-01

    The quasi-thermal noise (QTN) method consists in measuring the electrostatic fluctuations produced by the thermal motion of the ambient particles. This noise is detected with a sensitive wave receiver and measured at the terminal of a passive electric antenna, which is immersed in a stable plasma. The analysis of the so-called QTN provides in situ measurements, mainly the total electron density, with a good accuracy, and thermal temperature in a large number of space media. We create a preliminary electron database to analyse the anti-correlation between electron density and temperature deduced from WIND perigees in the Earth's plasmasphere. We analyse the radio power spectra measured by the Thermal Noise Receiver (TNR), using the 100-m long dipole antenna, onboard WIND spacecraft. We develop a systematic routine to determine the electron density, core and halo temperature and the magnitude of the magnetic field based on QTN in Bernstein modes. Indeed, the spectra are weakly banded between gyroharmonics below the upper hybrid frequency, from which we derive the local electron density. From the gyrofrequency determination, we obtain an independent measure of the magnetic field magnitude, which is in close agreement with the onboard magnetometer.

  12. Ascent Heating Thermal Analysis on the Spacecraft Adaptor (SA) Fairings and the Interface with the Crew Launch Vehicle (CLV)

    Science.gov (United States)

    Wang, Xiao-Yen; Yuko, James; Motil, Brian

    2009-01-01

    When the crew exploration vehicle (CEV) is launched, the spacecraft adaptor (SA) fairings that cover the CEV service module (SM) are exposed to aero heating. Thermal analysis is performed to compute the fairing temperatures and to investigate whether the temperatures are within the material limits for nominal ascent aero heating case. Heating rates from Thermal Environment (TE) 3 aero heating analysis computed by engineers at Marshall Space Flight Center (MSFC) are used in the thermal analysis. Both MSC Patran 2007r1b/Pthermal and C&R Thermal Desktop 5.1/Sinda models are built to validate each other. The numerical results are also compared with those reported by Lockheed Martin (LM) and show a reasonably good agreement.

  13. Analysis and quantification of the diversities of aerosol life cycles within AeroCom

    Directory of Open Access Journals (Sweden)

    C. Textor

    2006-01-01

    Full Text Available Simulation results of global aerosol models have been assembled in the framework of the AeroCom intercomparison exercise. In this paper, we analyze the life cycles of dust, sea salt, sulfate, black carbon and particulate organic matter as simulated by sixteen global aerosol models. The differences among the results (model diversities for sources and sinks, burdens, particle sizes, water uptakes, and spatial dispersals have been established. These diversities have large consequences for the calculated radiative forcing and the aerosol concentrations at the surface. Processes and parameters are identified which deserve further research. The AeroCom all-models-average emissions are dominated by the mass of sea salt (SS, followed by dust (DU, sulfate (SO4, particulate organic matter (POM, and finally black carbon (BC. Interactive parameterizations of the emissions and contrasting particles sizes of SS and DU lead generally to higher diversities of these species, and for total aerosol. The lower diversity of the emissions of the fine aerosols, BC, POM, and SO4, is due to the use of similar emission inventories, and does therefore not necessarily indicate a better understanding of their sources. The diversity of SO4-sources is mainly caused by the disagreement on depositional loss of precursor gases and on chemical production. The diversities of the emissions are passed on to the burdens, but the latter are also strongly affected by the model-specific treatments of transport and aerosol processes. The burdens of dry masses decrease from largest to smallest: DU, SS, SO4, POM, and BC. The all-models-average residence time is shortest for SS with about half a day, followed by SO4 and DU with four days, and POM and BC with six and seven days, respectively. The wet deposition rate is controlled by the solubility and increases from DU, BC, POM to SO4 and SS. It is the dominant sink for SO4, BC, and POM, and contributes about one third to the total removal

  14. The effect of harmonized emissions on aerosol properties in global models - an AeroCom experiment

    NARCIS (Netherlands)

    Textor, C.; Schulz, M.; Krol, M.C.

    2007-01-01

    The effects of unified aerosol sources on global aerosol fields simulated by different models are examined in this paper. We compare results from two AeroCom experiments, one with different (ExpA) and one with unified emissions, injection heights, and particle sizes at the source (ExpB). Surprisingl

  15. Computational methods to compute wavefront error due to aero-optic effects

    Science.gov (United States)

    Genberg, Victor; Michels, Gregory; Doyle, Keith; Bury, Mark; Sebastian, Thomas

    2013-09-01

    Aero-optic effects can have deleterious effects on high performance airborne optical sensors that must view through turbulent flow fields created by the aerodynamic effects of windows and domes. Evaluating aero-optic effects early in the program during the design stages allows mitigation strategies and optical system design trades to be performed to optimize system performance. This necessitates a computationally efficient means to evaluate the impact of aero-optic effects such that the resulting dynamic pointing errors and wavefront distortions due to the spatially and temporally varying flow field can be minimized or corrected. To this end, an aero-optic analysis capability was developed within the commercial software SigFit that couples CFD results with optical design tools. SigFit reads the CFD generated density profile using the CGNS file format. OPD maps are then created by converting the three-dimensional density field into an index of refraction field and then integrating along specified paths to compute OPD errors across the optical field. The OPD maps may be evaluated directly against system requirements or imported into commercial optical design software including Zemax® and Code V® for a more detailed assessment of the impact on optical performance from which design trades may be performed.

  16. Application of Multihop Relay for Performance Enhancement of AeroMACS Networks

    Science.gov (United States)

    Kamali, Behnam; Wilson, Jeffrey D.; Kerczewski, Robert J.

    2012-01-01

    A new transmission technology, based on IEEE 802.16-2009 (WiMAX), is currently being developed for airport surface communications. A C-band spectrum allocation at 5091 to 5150 MHz has been created by International Telecommunications Union (ITU) to carry this application. The proposed technology, known as AeroMACS, will be used to support fixed and mobile ground to ground applications and services. This article proposes and demonstrates that IEEE 802.16j-amendment-based WiMAX is most feasible for AeroMACS applications. This amendment introduces multihop relay as an optional deployment that may be used to provide additional coverage and/or enhance the capacity of the network. Particular airport surface radio coverage situations for which IEEE 802.16-2009-WiMAX provides resolutions that are inefficient, costly, or excessively power consuming are discussed. In all these cases, it is argued that 16j technology offers a much better alternative. A major concern about deployment of AeroMACS is interference to co-allocated applications such as the Mobile Satellite Service (MSS) feeder link. Our initial simulation results suggest that no additional interference to MSS feeder link is caused by deployment of IEEE 802.16j-based AeroMACS.

  17. RESEARCH AND DEVELOPMENT OF HIGH TEMPERATURE STRUCTURAL MATERIALS FOR AERO-ENGINE APPLICATIONS

    Institute of Scientific and Technical Information of China (English)

    G.Q. Zhang

    2005-01-01

    The status of research, development of superalloys and materials processing & fabrication technologies for aero-engine applications in China Aviation Industry, with an emphasis on recent achievements at BIAM including directionally solidified and single crystal superalloys for blade and vane applications, wrought superalloys for aero-engine disks and rings, and powder metallurgy (PM) superalloys for high performance disk applications were described. It was also reviewed the development of new class of high temperature structural materials, such as structural intermetallics, and advanced material processing technologies including rapid solidification,spray forming and so on. The trends of research and development of the above mentioned superalloys and processing technologies are outlined. Cast, wrought and PM superalloys are the workhorse materials for the hot section of current aero-engines. New high temperature materials and advanced processing technologies have been and will be the subject of study. It is speculated that high performance, high purity and low cost superalloys and technologies will play key roles in aero-engines.

  18. Analysis and quantification of the diversities of aerosol life cycles within AeroCom

    NARCIS (Netherlands)

    Textor, C.; Schulz, M.; Guibert, S.; Kinne, S.; Balkanski, Y.; Bauer, S.; Berntsen, T.; Berglen, T.; Boucher, O.; Chin, M.; Dentener, F.; Diehl, T.; Easter, R.; Feichter, H.; Fillmore, D.; Ghan, S.; Ginoux, P.; Gong, S.; Grini, A.; Hendricks, J.; Horowitz, L.; Huang, P.; Isaksen, I.; Iversen, T.; Kloster, S.; Koch, D.; Kirkevåg, A.; Kristjansson, J.E.; Krol, M.C.; Lauer, A.; Lamarque, J.F.; Liu, X.; Montanaro, V.; Myhre, G.; Penner, J.; Pitari, G.; Reddy, S.; Seland, O.; Stier, P.; Takemura, T.; Tie, X.

    2006-01-01

    Simulation results of global aerosol models have been assembled in the framework of the AeroCom intercomparison exercise. In this paper, we analyze the life cycles of dust, sea salt, sulfate, black carbon and particulate organic matter as simulated by sixteen global aerosol models. The differences a

  19. Large Wind Turbine Rotor Design using an Aero-Elastic / Free-Wake Panel Coupling Code

    DEFF Research Database (Denmark)

    Sessarego, Matias; Ramos García, Néstor; Shen, Wen Zhong;

    2016-01-01

    Despite the advances in computing resources in the recent years, the majority of large wind-turbine rotor design problems still rely on aero-elastic codes that use blade element momentum (BEM) approaches to model the rotor aerodynamics. The present work describes an approach to wind-turbine rotor...

  20. 76 FR 27872 - Airworthiness Directives; PIAGGIO AERO INDUSTRIES S.p.A Model P-180 Airplanes

    Science.gov (United States)

    2011-05-13

    ... INDUSTRIES S.p.A Model P- 180 Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ] ACTION: Final... known U.S. owners and operators of PIAGGIO AERO INDUSTRIES S.p.A (Piaggio) Model PIAGGIO P-180 airplanes... fuselage on a number of Piaggio Model P.180 aeroplanes, which resulted in jamming of the flight...

  1. 77 FR 63712 - Airworthiness Directives; Piaggio Aero Industries S.p.A.

    Science.gov (United States)

    2012-10-17

    ... Industries S.p.A. AGENCY: Federal Aviation Administration (FAA), Department of Transportation (DOT). ACTION... Aero Industries S.p.A Model P-180 airplanes. That AD was prompted by mandatory continuing airworthiness... replaced for damage in the P.180 fleet since that occurrence. Based on the available information, this...

  2. 75 FR 5690 - Airworthiness Directives; PIAGGIO AERO INDUSTRIES S.p.A. Model P-180 Airplanes

    Science.gov (United States)

    2010-02-04

    ... INDUSTRIES S.p.A. Model P- 180 Airplanes AGENCY: Federal Aviation Administration (FAA), Department of... between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM...: 2010-03-04 PIAGGIO AERO INDUSTRIES S.p.A.: Amendment 39-16187; Docket No. FAA-2009-1081;...

  3. Recognition and practice on remanufacturing engineering management of military aero-engines

    Institute of Scientific and Technical Information of China (English)

    Xiang Qiao

    2014-01-01

    The technologies of design,manufacture and MRO (maintenance,repair and overhaul) for the mili-tary aero-engines,particularly for the fighters,are much more difficult to be mastered than those for any other aero-engines. They have been monopolized by only a few countries and the core technologies have never been transferred due to high risk,high investment,high barrier and high cost. Therefore,our country has long relied on mapping and copying the others’engines to satisfy the domestic demand due to not having our own indepen-dent technologies for the design and manufacture of military aero-engines. However,through over 20 years of unremitting effort,the independent MRO has been achieved for all the Chinese fighter engines,covering in-R&D (research and development) and in-service engines;and the MRO technologies,capabilities,quality, cost-efficiency have reached or exceeded those of original manufacturers. It has grown out of nothing,and then from weak to strong. In particular,dozens of projects concerning the R&D and engineering application of re-manufacturing have obtained the independent intellectual property rights and are playing an irreplaceable role in achieving leaping improvement of independent MRO for Chinese military aero-engines.

  4. Recognition and practice on remanufacturing engineering management of military aero-engines

    Institute of Scientific and Technical Information of China (English)

    Xiang Qiao

    2014-01-01

    The technologies of design, manufacture and MRO (maintenance, repair and overhaul) tor the mili- tary aero-engines, particularly for the fighters, are much more difficult to be mastered than those for any other aero-engines. They have been monopolized by only a few countries and the core technologies have never been transferred due to high risk, high investment, high barrier and high cost. Therefore, our country has long relied on mapping and copying the others' engines to satisfy the domestic demand due to not having our own indepen- dent technologies for the design and manufacture of military aero-engines. However, through over 20 years of unremitting effort, the independent MRO has been achieved for all the Chinese fighter engines, covering in- R&D (research and development) and in-service engines; and the MRO technologies, capabilities, quality, cost-efficiency have reached or exceeded those of original manufacturers. It has grown out of nothing, and then from weak to strong. In particular, dozens of projects concerning the R&D and engineering application of re- manufacturing have obtained the independent intellectual property rights and are playing an irreplaceable role in achieving leaping improvement of independent MRO for Chinese military aero-engines.

  5. The secondary structure and the thermal unfolding parameters of the S-layer protein from Lactobacillus salivarius.

    Science.gov (United States)

    Lighezan, Liliana; Georgieva, Ralitsa; Neagu, Adrian

    2016-09-01

    Surface layer (S-layer) proteins have been identified in the cell envelope of many organisms, such as bacteria and archaea. They self-assemble, forming monomolecular crystalline arrays. Isolated S-layer proteins are able to recrystallize into regular lattices, which proved useful in biotechnology. Here we investigate the structure and thermal unfolding of the S-layer protein isolated from Lactobacillus salivarius 16 strain of human origin. Using circular dichroism (CD) spectroscopy, and the software CDSSTR from DICHROWEB, CONTINLL from CDPro, as well as CDNN, we assess the fractions of the protein's secondary structural elements at temperatures ranging between 10 and 90 °C, and predict the tertiary class of the protein. To study the thermal unfolding of the protein, we analyze the temperature dependence of the CD signal in the far- and near-UV domains. Fitting the experimental data by two- and three-state models of thermal unfolding, we infer the midpoint temperatures, the temperature dependence of the changes in Gibbs free energy, enthalpy, and entropy of the unfolding transitions in standard conditions, and the temperature dependence of the equilibrium constant. We also estimate the changes in heat capacity at constant pressure in standard conditions. The results indicate that the thermal unfolding of the S-layer protein from L. salivarius is highly cooperative, since changes in the secondary and tertiary structures occur simultaneously. The thermodynamic analysis predicts a "cold" transition, at about -3 °C, of both the secondary and tertiary structures. Our findings may be important for the use of S-layer proteins in biotechnology and in biomedical applications.

  6. Xe distribution in amorphous SiO{sub 2} as a function of implantation and thermal annealing parameters

    Energy Technology Data Exchange (ETDEWEB)

    Naas, A., E-mail: abdelkrim_naas@yahoo.fr [Conditions Extrêmes et Matériaux: Haute Température et Irradiation (CEMHT) CNRS, 3A rue de la Férollerie, 45071 Orléans (France); Materials Science and Informatics Laboratory, University of Djelfa, 17000 (Algeria); Ntsoenzok, E.; De Sousa-Meneses, D.; Hakim, B. [Conditions Extrêmes et Matériaux: Haute Température et Irradiation (CEMHT) CNRS, 3A rue de la Férollerie, 45071 Orléans (France); Beya-Wakata, A. [Département Physique, Université de Yaoundé 1 (Cameroon)

    2014-11-15

    Highlights: • We studied the distribution of implanted Xe in amorphous SiO{sub 2}. • Various energies and fluencies as well as thermal annealing were considered. • RBS and TEM characterizations were undertaken. • We demonstrated that Xe can be located at vacancy peak or at ion projected range. • When a dense layer of bubbles is formed, Xe is shifted to stable bubbles region. - Abstract: We studied the distribution of implanted Xe in amorphous SiO{sub 2}. Our results clearly showed that Xe profile is energy and fluence dependent. By varying ion energy from 50 to 300 keV, we found that its thermal out-diffusion is very conventional for the first two energies and unexpected for the highest energy. In that last case Xe main peak increases with thermal annealing. Instead of out-diffusing, Xe seems to be driven toward the main peak. The effect of ion fluence is similar to energy one with a conventional out-diffusion for lower fluences (5 × 10{sup 15} and 1 × 10{sup 16} cm{sup −2}) while higher fluences (3.5 × 10{sup 16} and 5 × 10{sup 16} cm{sup −2}) display an increase of the main peak with annealing. Such a behavior can be linked to the formation (or not) of a high density of stable bubbles.

  7. Effect of Processing Parameters on Thermal Cycling Behavior of Al2O3-Al2O3 Brazed Joints

    Science.gov (United States)

    Dandapat, Nandadulal; Ghosh, Sumana; Guha, Bichitra Kumar; Datta, Someswar; Balla, Vamsi Krishna

    2016-10-01

    In the present study, alumina ceramics were active metal brazed at different temperatures ranging from 1163 K to 1183 K (890 °C to 910 °C) using TICUSIL (68.8Ag-26.7Cu-4.5Ti in wt pct) foil as filler alloy of different thicknesses. The brazed joints were subjected to thermal cycling for 100 cycles between 323 K and 873 K (50 °C and 600 °C). The microstructural and elemental composition analysis of the brazed joints were performed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) before and after thermal cycling. Helium (He) leak test and brazing strength measurement were also conducted after thermal cycling for 100 cycles. The joint could withstand up to 1 × 10-9 Torr pressure and brazing strength was higher than 20 MPa. The experimental results demonstrated that joints brazed at the higher temperature with thinner filler alloy produced strong Al2O3-Al2O3 joints.

  8. Effects of heavy metals/metalloids present in fly ash from coal fired thermal power plant on photosynthetic parameters of Mangifera indica

    Directory of Open Access Journals (Sweden)

    Neelima Meravi

    2014-12-01

    Full Text Available In the present work heavy metals/metalloids present in the fly ash emitted from a coal fired thermal power plant was estimated. The effects of heavy metals/metalloids present in the ash on various photosynthetic parameters (fluorescence, Fv/Fm, fluorescence quenching coefficients, relative electron transport rate, photosynthetic active radiation, ETR-Factor absorptance of photons by photosynthetic pigments etc. were estimated. Heavy metals/metalloids were estimated using atomic absorption spectrophotometer (AAS, 7000 Shimadzu for Fe, Zn, Pb, Cd, Mo, Cu, Cr, Co and Ni and the standard solution was prepared using standard metal solution of Inorganic Ventures. Various photosynthetic parameters were estimated using JUNIOR-PAM, Chlorophyll Fluorometer, Heinz Walz GmbH, Germany. It was clear from the observed value of Fv/Fm (0.717 that the heavy metals/metalloids present in the fly have negative effects on plants because for a healthy plant Fv/Fm should not be less than 0.75. Similarly other parameters were also adversely affected by the presence of heavy metals/metalloids present in the fly ash that were deposited on the plants leaves. Therefore, the issue of fly ash emitted from thermal power plants need to be addressed in a proper way.

  9. Laser thermal effect on silicon nitride ceramic based on thermo-chemical reaction with temperature-dependent thermo-physical parameters

    Science.gov (United States)

    Pan, A. F.; Wang, W. J.; Mei, X. S.; Wang, K. D.; Zhao, W. Q.; Li, T. Q.

    2016-07-01

    In this study, a two-dimensional thermo-chemical reaction model with temperature-dependent thermo-physical parameters on Si3N4 with 10 ns laser was developed to investigate the ablated size, volume and surface morphology after single pulse. For model parameters, thermal conductivity and heat capacity of β-Si3N4 were obtained from first-principles calculations. Thermal-chemical reaction rate was fitted by collision theory, and then, reaction element length was deduced using the relationship between reaction rate and temperature distribution. Furthermore, plasma absorption related to energy loss was approximated as a function of electron concentration in Si3N4. It turned out that theoretical ablated volume and radius increased and then remained constant with increasing laser energy, and the maximum ablated depth was not in the center of the ablated zone. Moreover, the surface maximum temperature of Si3N4 was verified to be above 3000 K within pulse duration, and it was much higher than its thermal decomposition temperature of 1800 K, which indicated that Si3N4 was not ablated directly above the thermal decomposition temperature. Meanwhile, the single pulse ablation of Si3N4 was performed at different powers using a TEM00 10 ns pulse Nd:YAG laser to validate the model. The model showed a satisfactory consistence between the experimental data and numerical predictions, presenting a new modeling technology that may significantly increase the accuracy of the predicated results for laser ablation of materials undergoing thermo-chemical reactions.

  10. Development of a CuNiCrAl Bond Coat for Thermal Barrier Coatings in Rocket Combustion Chambers

    Science.gov (United States)

    Fiedler, Torben; Rösler, Joachim; Bäker, Martin

    2015-12-01

    The lifetime of rocket combustion chambers can be increased by applying thermal barrier coatings. The standard coating systems usually used in gas turbines or aero engines will fail at the bond coat/substrate interface due to the chemical difference as well as the different thermal expansion between the copper liner and the applied NiCrAlY bond coat. A new bond coat alloy for rocket engine applications was designed previously with a chemical composition and coefficient of thermal expansion more similar to the copper substrate. Since a comparable material has not been applied by thermal spraying before, coating tests have to be carried out. In this work, the new Ni-30%Cu-6%Al-5%Cr bond coat alloy is applied via high velocity oxygen fuel spraying. In a first step, the influence of different coating parameters on, e.g., porosity, amount of unmolten particles, and coating roughness is investigated and a suitable parameter set for further studies is chosen. In a second step, copper substrates are coated with the chosen parameters to test the feasibility of the process. The high-temperature behavior and adhesion is tested with laser cycling experiments. The new coatings showed good adhesion even at temperatures beyond the maximum test temperatures of the NiCrAlY bond coat in previous studies.

  11. Validation of CENDL and JEFF evaluated nuclear data files for TRIGA calculations through the analysis of integral parameters of TRX and BAPL benchmark lattices of thermal reactors

    Energy Technology Data Exchange (ETDEWEB)

    Uddin, M.N. [Department of Physics, Jahangirnagar University, Dhaka (Bangladesh); Sarker, M.M. [Reactor Physics and Engineering Division, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Savar, GPO Box 3787, Dhaka 1000 (Bangladesh); Khan, M.J.H. [Reactor Physics and Engineering Division, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Savar, GPO Box 3787, Dhaka 1000 (Bangladesh)], E-mail: jahirulkhan@yahoo.com; Islam, S.M.A. [Department of Physics, Jahangirnagar University, Dhaka (Bangladesh)

    2009-10-15

    The aim of this paper is to present the validation of evaluated nuclear data files CENDL-2.2 and JEFF-3.1.1 through the analysis of the integral parameters of TRX and BAPL benchmark lattices of thermal reactors for neutronics analysis of TRIGA Mark-II Research Reactor at AERE, Bangladesh. In this process, the 69-group cross-section library for lattice code WIMS was generated using the basic evaluated nuclear data files CENDL-2.2 and JEFF-3.1.1 with the help of nuclear data processing code NJOY99.0. Integral measurements on the thermal reactor lattices TRX-1, TRX-2, BAPL-UO{sub 2}-1, BAPL-UO{sub 2}-2 and BAPL-UO{sub 2}-3 served as standard benchmarks for testing nuclear data files and have also been selected for this analysis. The integral parameters of the said lattices were calculated using the lattice transport code WIMSD-5B based on the generated 69-group cross-section library. The calculated integral parameters were compared to the measured values as well as the results of Monte Carlo Code MCNP. It was found that in most cases, the values of integral parameters show a good agreement with the experiment and MCNP results. Besides, the group constants in WIMS format for the isotopes U-235 and U-238 between two data files have been compared using WIMS library utility code WILLIE and it was found that the group constants are identical with very insignificant difference. Therefore, this analysis reflects the validation of evaluated nuclear data files CENDL-2.2 and JEFF-3.1.1 through benchmarking the integral parameters of TRX and BAPL lattices and can also be essential to implement further neutronic analysis of TRIGA Mark-II research reactor at AERE, Dhaka, Bangladesh.

  12. Spark Plasma Sintering constrained process parameters of sintered silver paste for connection in power electronic modules: Microstructure, mechanical and thermal properties

    Energy Technology Data Exchange (ETDEWEB)

    Alayli, N. [Université Paris 13, Sorbonne Paris Cité, Laboratoire des Sciences des Procédés et des Matériaux, Centre National de la Recherche Scientifique, Unité Propre de Recherche 3407, 99 avenue Jean Baptiste Clément, F-93430 Villetaneuse (France); Université de Versailles-Saint-Quentin-en-Yvelines, Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Centre National de la Recherche Scientifique/INSU, Laboratoire Atmosphères Milieux Observations Spatiales-IPSL, Quartier des Garennes, 11 Boulevard d' Alembert, F-78280 Guyancourt (France); Schoenstein, F., E-mail: frederic.schoenstein@univ-paris13.fr [Université Paris 13, Sorbonne Paris Cité, Laboratoire des Sciences des Procédés et des Matériaux, Centre National de la Recherche Scientifique, Unité Propre de Recherche 3407, 99 avenue Jean Baptiste Clément, F-93430 Villetaneuse (France); Girard, A. [Office National d' Étude et de Recherches Aérospatiales, Laboratoire d' Étude des Microstructures, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 104, 29 avenue de la Division Leclerc, F-92322 Châtillon (France); and others

    2014-11-14

    Processing parameters of Spark Plasma Sintering (SPS) technique were constrained to process nano sized silver particles bound in a paste for interconnection in power electronic devices. A novel strategy combining debinding step and consolidation processes (SPS) in order to elaborate nano-structured silver bulk material is investigated. Optimum parameters were sought for industrial power electronics packaging from the microstructural and morphological properties of the sintered material. The latter was studied by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) to determine the density and the grain size of crystallites. Two types of samples, termed S1 (bulk) and S2 (multilayer) were elaborated and characterized. They are homogeneous with a low degree of porosity and a good adhesion to the substrate and the process parameters are compatible with industrial constraints. As the experimental results show, the mean crystallite size is between 60 nm and 790 nm with a density between 50% and 92% resulting in mechanical and thermal properties that are better than that of lead free solder. The best SPS sintering parameters, the applied pressure, the temperature and the processing time were determined as being 3 MPa, 300 °C and 1 min respectively when the desizing time of the preprocessing step was kept below 5 min at 150 °C. Using these processing parameters, acceptable for automotive packaging industry, a semi-conductor power chip was successfully connected to a metalized substrate by sintered silver with thermal and electrical properties better than those of current solders and with thermomechanical properties allowing absorption of thermoplastic stresses. - Highlights: • The sintered silver joints have nanometric structure. • The grain growth was controlled by the SPS sintering parameters. • New connection material improve thermal and electrical properties of current solders. • Interconnection's plastic strain can absorb thermo

  13. Kinetic parameters, collision rates, energy exchanges and transport coefficients of non-thermal electrons in premixed flames at sub-breakdown electric field strengths

    Science.gov (United States)

    Bisetti, Fabrizio; El Morsli, Mbark

    2014-01-01

    The effects of an electric field on the collision rates, energy exchanges and transport properties of electrons in premixed flames are investigated via solutions to the Boltzmann kinetic equation. The case of high electric field strength, which results in high-energy, non-thermal electrons, is analysed in detail at sub-breakdown conditions. The rates of inelastic collisions and the energy exchange between electrons and neutrals in the reaction zone of the flame are characterised quantitatively. The analysis includes attachment, ionisation, impact dissociation, and vibrational and electronic excitation processes. Our results suggest that Townsend breakdown occurs for E/N = 140 Td. Vibrational excitation is the dominant process up to breakdown, despite important rates of electronic excitation of CO, CO2 and N2 as well as impact dissociation of O2 being apparent from 50 Td onwards. Ohmic heating in the reaction zone is found to be negligible (less than 2% of peak heat release rate) up to breakdown field strengths for realistic electron densities equal to 1010 cm-3. The observed trends are largely independent of equivalence ratio. In the non-thermal regime, electron transport coefficients are insensitive to mixture composition and approximately constant across the flame, but are highly dependent on the electric field strength. In the thermal limit, kinetic parameters and transport coefficients vary substantially across the flame due to the spatially inhomogeneous concentration of water vapour. A practical approach for identifying the plasma regime (thermal versus non-thermal) in studies of electric field effects on flames is proposed.

  14. Kinetic parameters, collision rates, energy exchanges and transport coefficients of non-thermal electrons in premixed flames at sub-breakdown electric field strengths

    KAUST Repository

    Bisetti, Fabrizio

    2014-01-02

    The effects of an electric field on the collision rates, energy exchanges and transport properties of electrons in premixed flames are investigated via solutions to the Boltzmann kinetic equation. The case of high electric field strength, which results in high-energy, non-thermal electrons, is analysed in detail at sub-breakdown conditions. The rates of inelastic collisions and the energy exchange between electrons and neutrals in the reaction zone of the flame are characterised quantitatively. The analysis includes attachment, ionisation, impact dissociation, and vibrational and electronic excitation processes. Our results suggest that Townsend breakdown occurs for E/N = 140 Td. Vibrational excitation is the dominant process up to breakdown, despite important rates of electronic excitation of CO, CO2 and N2 as well as impact dissociation of O2 being apparent from 50 Td onwards. Ohmic heating in the reaction zone is found to be negligible (less than 2% of peak heat release rate) up to breakdown field strengths for realistic electron densities equal to 1010 cm-3. The observed trends are largely independent of equivalence ratio. In the non-thermal regime, electron transport coefficients are insensitive to mixture composition and approximately constant across the flame, but are highly dependent on the electric field strength. In the thermal limit, kinetic parameters and transport coefficients vary substantially across the flame due to the spatially inhomogeneous concentration of water vapour. A practical approach for identifying the plasma regime (thermal versus non-thermal) in studies of electric field effects on flames is proposed. © 2014 Taylor & Francis.

  15. Dependence of Characteristic Diode Parameters in Ni/n-GaAs Contacts on Thermal Annealing and Sample Temperature

    Science.gov (United States)

    Yildirim, N.; Dogan, H.; Korkut, H.; Turut, A.

    We have prepared the sputtered Ni/n-GaAs Schottky diodes which consist of as-deposited, and diodes annealed at 200 and 400°C for 2 min. The effect of thermal annealing on the temperature-dependent current-voltage (I-V) characteristics of the diodes has been experimentally investigated. Their I-V characteristics have been measured in the temperature range of 60-320 K with steps of 20 K. It has been seen that the barrier height (BH) slightly increased from 0.84 (as-deposited sample) to 0.88 eV at 300 K when the contact has been annealed at 400°C. The SBH increased whereas the ideality factor decreased with increasing annealing temperature for each sample temperature. The I-V measurements showed a dependence of ideality factor n and BH on the measuring temperature that cannot be explained by the classical thermionic emission theory. The experimental data are consistent with the presence of an inhomogeneity of the SBHs. Therefore, the temperature dependent I-V characteristics of the diodes have been discussed in terms of the multi-Gaussian distribution model. The experimental data good have agree with the fitting curves over whole measurement temperature range indicating that the SBH inhomogeneity of our as-deposited and annealed Ni/n-GaAs SBDs can be well-described by a double-Gaussian distribution. The slope of the nT versus T plot for the samples has approached to unity with increasing annealing temperature and becomes parallel to that of the ideal Schottky contact behavior for the 400°C annealed diode. Thus, it has been concluded that the thermal annealing process translates the metal-semiconductor contacts into thermally stable Schottky contacts.

  16. The influence of precursor source and thermal parameters upon the formation of beta-phase molybdenum nitride

    Energy Technology Data Exchange (ETDEWEB)

    Cairns, A.G.; Gallagher, J.G. [WestCHEM, Department of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Hargreaves, J.S.J. [WestCHEM, Department of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ (United Kingdom)], E-mail: justinh@chem.gla.ac.uk; Mckay, D.; Morrison, E. [WestCHEM, Department of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Rico, J.L. [Laboratorio de Catalisis, Facultad de Ingenieria Quimica, Universidad Michoacana, Edificio E, CU, Morelia Mich, C.P. 58060 (Mexico)], E-mail: jlrico@umich.mx; Wilson, K. [WestCHEM, Department of Chemistry, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

    2009-06-24

    In the present paper the effect of the MoO{sub 3} precursor and procedure on the synthesis of beta-phase molybdenum nitride is reported. Two different sources of MoO{sub 3} were used, and treated under a flow of gas N{sub 2}/H{sub 2} at 700 or 750 deg. C employing various heating ramp rates. All samples were characterized by XRD, SEM and their textural properties were determined by application of the BET method. The results show that, depending on the precursor, markedly different morphologies were observed, whereas both the molybdenum source and the thermal treatment, strongly influence the incorporation of nitrogen.

  17. A multi-scale model for geared transmission aero-thermodynamics

    Science.gov (United States)

    McIntyre, Sean M.

    A multi-scale, multi-physics computational tool for the simulation of high-per- formance gearbox aero-thermodynamics was developed and applied to equilibrium and pathological loss-of-lubrication performance simulation. The physical processes at play in these systems include multiphase compressible ow of the air and lubricant within the gearbox, meshing kinematics and tribology, as well as heat transfer by conduction, and free and forced convection. These physics are coupled across their representative space and time scales in the computational framework developed in this dissertation. These scales span eight orders of magnitude, from the thermal response of the full gearbox O(100 m; 10 2 s), through effects at the tooth passage time scale O(10-2 m; 10-4 s), down to tribological effects on the meshing gear teeth O(10-6 m; 10-6 s). Direct numerical simulation of these coupled physics and scales is intractable. Accordingly, a scale-segregated simulation strategy was developed by partitioning and treating the contributing physical mechanisms as sub-problems, each with associated space and time scales, and appropriate coupling mechanisms. These are: (1) the long time scale thermal response of the system, (2) the multiphase (air, droplets, and film) aerodynamic flow and convective heat transfer within the gearbox, (3) the high-frequency, time-periodic thermal effects of gear tooth heating while in mesh and its subsequent cooling through the rest of rotation, (4) meshing effects including tribology and contact mechanics. The overarching goal of this dissertation was to develop software and analysis procedures for gearbox loss-of-lubrication performance. To accommodate these four physical effects and their coupling, each is treated in the CFD code as a sub problem. These physics modules are coupled algorithmically. Specifically, the high- frequency conduction analysis derives its local heat transfer coefficient and near-wall air temperature boundary conditions from a quasi

  18. Influence of Processing Parameters on Residual Stress of High Velocity Oxy-Fuel Thermally Sprayed WC-Co-Cr Coating

    Science.gov (United States)

    Gui, M.; Eybel, R.; Asselin, B.; Radhakrishnan, S.; Cerps, J.

    2012-10-01

    Residual stress in high velocity oxy-fuel (HVOF) thermally sprayed WC-10Co-4Cr coating was studied based on design of experiment (DOE) with five factors of oxygen flow, fuel gas hydrogen flow, powder feed rate, stand-off distance, and surface speed of substrate. In each DOE run, the velocity and temperature of in-flight particle in flame, and substrate temperature were measured. Almen-type N strips were coated, and their deflections after coating were used for evaluation of residual stress level in the coating. The residual stress in the coating obtained in all DOE runs is compressive. In the present case of HVOF thermally sprayed coating, the residual stress is determined by three types of stress: peening, quenching, and cooling stress generated during spraying or post spraying. The contribution of each type stress to the final compressive residual stress in the coating depends on material properties of coating and substrate, velocity and temperature of in-flight particle, and substrate temperature. It is found that stand-off distance is the most important factor to affect the final residual stress in the coating, following by two-factor interaction of oxygen flow and hydrogen flow. At low level of stand-off distance, higher velocity of in-flight particle in flame and higher substrate temperature post spraying generate more peening stress and cooling stress, resulting in higher compressive residual stress in the coating.

  19. R-MATRIX RESONANCE ANALYSIS AND STATISTICAL PROPERTIES OF THE RESONANCE PARAMETERS OF 233U IN THE NEUTRON ENERGY RANGE FROM THERMAL TO 600 eV

    Energy Technology Data Exchange (ETDEWEB)

    Leal, L.C.

    2001-02-27

    The R-matrix resonance analysis of experimental neutron transmission and cross sections of {sup 233}U, with the Reich-Moore Bayesian code SAMMY, was extended up to the neutron energy of 600 eV by taking advantage of new high resolution neutron transmission and fission cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA). The experimental data base is described. In addition to the microscopic data (time-of-flight measurements of transmission and cross sections), some experimental and evaluated integral quantities were included in the data base. Tabulated and graphical comparisons between the experimental data and the SAMMY calculated cross sections are given. The ability of the calculated cross sections to reproduce the effective multiplication factors k{sub eff} for various thermal, intermediate, and fast systems was tested. The statistical properties of the resonance parameters were examined and recommended values of the average s-wave resonance parameters are given.

  20. Fusing Simulation Results From Multifidelity Aero-servo-elastic Simulators - Application To Extreme Loads On Wind Turbine

    DEFF Research Database (Denmark)

    Abdallah, Imad; Sudret, Bruno; Lataniotis, Christos

    2015-01-01

    Fusing predictions from multiple simulators in the early stages of the conceptual design of a wind turbine results in reduction in model uncertainty and risk mitigation. Aero-servo-elastic is a term that refers to the coupling of wind inflow, aerodynamics, structural dynamics and controls. Fusing...... the response data from multiple aero-servo-elastic simulators could provide better predictive ability than using any single simulator. The co-Kriging approach to fuse information from multifidelity aero-servo-elastic simulators is presented. We illustrate the co-Kriging approach to fuse the extreme flapwise...... bending moment at the blade root of a large wind turbine as a function of wind speed, turbulence and shear exponent in the presence of model uncertainty and non-stationary noise in the output. The extreme responses are obtained by two widely accepted numerical aero-servo-elastic simulators, FAST...

  1. Dual-frequency Eddy Current Non-destructive Detection of Fatigue Cracks in Compressor Discs of Aero Engines

    National Research Council Canada - National Science Library

    B. Sasi; B.P.C. Rao; T. Jayakumar

    2004-01-01

    ... related aircraft components. This paper discusses a dual-frequency eddy current testing procedure developed for inspection of compressor discs of aero engines for detecting fatigue cracks with high sensitivity and reliability...

  2. Smart Rotor Modeling: Aero-Servo-Elastic Modeling of a Smart Rotor with Adaptive Trailing Edge Flaps

    DEFF Research Database (Denmark)

    Bergami, Leonardo

    This book presents the formulation of an aero-servo-elastic model for a wind turbine rotor equipped with Adaptive Trailing Edge Flaps (ATEF), a smart rotor configuration. As the name suggests, an aero-servo-elastic model consists of three main components: an aerodynamic model, a structural model......, and a control model. The book first presents an engineering type of aerodynamic model that accounts for the dynamic effects of flap deflection. The aerodynamic model is implemented in a Blade Element Momentum framework, and coupled with a multi-body structural model in the aero-servoelastic simulation code HAWC...... the trailing edge flap deflection to actively reduce the fatigue loads on the structure. The performance of the smart rotor configuration and its control algorithms are finally quantified by aero-servo-elastic simulations of the smart rotor turbine operating in a standard turbulent wind field....

  3. Thermal characterization and determination of recombination parameters in CdTe films on glass substrates by using open photoacoustic cell technique

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-T, M.A. [Depto. de C. Basicas, ESCOM-IPN, Av. Miguel Othon de Mendizabal S/N, Col. Lindavista, CP 07738, Mexico DF (Mexico)]. E-mail: mgonzalezt@ipn.mx; Cruz-Orea, A. [Depto. de Fisica, CINVESTAV-IPN, Av. IPN No.2508, Col. San Pedro Zacatenco, CP. 07360, Mexico DF (Mexico); Albor-A, M.L. de [Depto. de Fisica, ESFM-IPN, Edif. 9, U.P. ' Adolfo Lopez Mateos' , CP 07738, Mexico DF (Mexico); Castillo-A, F. de L [Depto. de Fisica, ESFM-IPN, Edif. 9, U.P. ' Adolfo Lopez Mateos' , CP 07738, Mexico DF (Mexico)

    2005-06-01

    CdTe is a semiconductor with a wide variety of applications and perspectives for electronic industry (high-efficiency photoelectric cells, infrared radiation detectors, etc.). In the present work, we used photoacoustic (PA) technique to study the thermal properties and the surface recombination velocity in CdTe/glass samples. Experimental PA phase signal as a function of modulation frequency in a heat transmission configuration was fitted to the theoretical expression for PA signal, which takes into account the heat sources resulting from the absorption of light in semiconductors and the nonradiative processes involved, which depend on their thermal, optical and electronic transport properties. By this procedure, it was possible to determine the thermal diffusivity and the surface recombination velocity in these samples. The studied samples were thin polycrystalline CdTe film deposited on glass slides. CdTe layers were deposited by a hot-wall closed-spaced vapor transport method, known as gradient recrystallization and growth. The values for the deposition parameters used in this study were the following: 700 deg. C for the source temperature and 450 and 550 deg. C for the substrate temperatures with three different deposition times from 5 to 20 min (then three different film thicknesses were obtained). A clear increment in the surface velocity and surface roughness is observed as the film thickness is increased.

  4. Effect of Tool and Milling Parameters on the Size Distribution of Splinters of Planed Native and Thermally Modified Beech Wood

    Directory of Open Access Journals (Sweden)

    Štefan Barcík

    2014-01-01

    Full Text Available This paper deals with splinter size analysis of beech wood, considering the angular tool of the cutter and also the physical and mechanical wood properties substantially influencing wood processing technology. Particle size analysis was conducted by sieving the samples using a set of laboratory sieves, with subsequent determination of the individual fraction shares. The results have been compared with respect to the possibility of wood waste separation and filtration, and its subsequent utilization, above all, in the production of agglomerated materials and production of wood briquettes and pellets. The most frequently occurring fractions in native beech samples range between 5 and 8 mm and between 2 and 5 mm, while powder fractions below 125 μm were found in less than 1% of investigated samples. The most frequently occurring fractions in thermally modified beech wood ranged from 0.5 to 1 mm, and the share of powder wood particles below 125 μm was less than 4%.

  5. Numerical simulation of polyester coextrusion: Influence of the thermal parameters and the die geometry on interfacial instabilities

    Science.gov (United States)

    Mahdaoui, O.; Agassant, J.-F.; Laure, P.; Valette, R.; Silva, L.

    2007-04-01

    The polymer coextrusion process is a new method of sheet metal lining. It allows to substitute lacquers for steel protection in food packaging industry. The coextrusion process may exhibit flow instabilities at the interface between the two polymer layers. The objective of this study is to check the influence of processing and rheology parameters on the instabilities. Finite elements numerical simulations of the coextrusion allow to investigate various stable and instable flow configurations.

  6. Shock Response and Dynamic Failure of Spatially Tailored Aero-Thermal Structures

    Science.gov (United States)

    2012-09-15

    and Nanolayered Titanium Aluminum Carbide (a MAX phase material) under varying rates of loading and at different temperatures. The Johnson - Cook ...Development of Johnson - Cook constitutive model for Hastelloy X at different temperatures and strain rates.  Analytical development of steady...which it showed a peak at 900°C before beginning to decrease again as the temperature was further increased. The Johnson - Cook model was used to predict

  7. Experimental Study of Helical Shape Memory Alloy Actuators: Effects of Design and Operating Parameters on Thermal Transients and Stroke

    Directory of Open Access Journals (Sweden)

    Shane J. Yates

    2013-02-01

    Full Text Available Shape memory alloy actuators’ strokes can be increased at the expense of recovery force via heat treatment to form compressed springs in their heat-activated, austenitic state. Although there are models to explain their behaviour, few investigations present experimental results for support or validation. The aim of the present paper is to determine via experimentation how certain parameters affect a helical shape memory alloy actuator’s outputs: its transformation times and stroke. These parameters include wire diameter, spring diameter, transition temperature, number of active turns, bias force and direct current magnitude. Six investigations were performed: one for each parameter manipulation. For repeatability and to observe thermo-mechanical training effects, the springs were cyclically activated. The resultant patterns were compared with results predicted from one-dimensional models to elucidate the findings. Generally, it was observed that the transformation times and strokes converged at changing stress levels; the convergence is likely the peak where the summation of elastic stroke and transformation stroke has reached its maximum. During cyclic loading, the actuators’ strokes decreased to a converged value, particularly at larger internal stresses; training should therefore be performed prior to the actuator’s implementation for continual use applications.

  8. The effects of post-thermal annealing on the optical parameters of indium-doped ZnO thin films

    Institute of Scientific and Technical Information of China (English)

    Peng Li-Ping; Fang Liang; Wu Wei-Dong; Wang Xue-Min; Li Li

    2012-01-01

    Indium-doped ZnO thin films are deposited on quartz glass slides by RF magnetron sputtering at ambient temperature.The as-deposited films are annealed at different temperatures from 400 ℃ to 800 ℃ in air for 1 h.Transmittance spectra are used to determine the optical parameters and the thicknesses of the films before and after annealing using a nonlinear programming method,and the effects of the annealing temperatures on the optical parameters and the thickness are investigated.The optical band gap is determined from the absorption coefficient.The calculated results show that the film thickness and optical parameters both increase first and then decrease with increasing annealing temperature from 400 ℃ to 800 ℃.The band gap of the as-deposited ZnO:In thin film is 3.28 eV,and it decreases to 3.17 eV after annealing at 400 ℃.Then the band gap increases from 3.17 eV to 3.23 eV with increasing annealing temperature from 400 ℃ to 800 ℃.

  9. Computational Aero-acoustics As a Tool For Turbo-machinery Noise Reduction

    Science.gov (United States)

    Dyson, Rodger W.

    2003-01-01

    This talk will provide an overview of the field of computational aero-acoustics and its use in fan noise prediction. After a brief history of computational fluid dynamics, some of the recent developments in computational aero-acoustics will be explored. Computational issues concerning sound wave production, propagation, and reflection in practical turbo-machinery applications will be discussed including: (a) High order/High Resolution Numerical Techniques. (b) High Resolution Boundary Conditions. [c] MIMD Parallel Computing. [d] Form of Governing Equations Useful for Simulations. In addition, the basic design of our Broadband Analysis Stator Simulator (BASS) code and its application to a 2 D rotor wake-stator interaction will be shown. An example of the noise produced by the wakes from a rotor impinging upon a stator cascade will be shown.

  10. Aero-allergens in canine atopic dermatitis in southeastern Australia based on 1000 intradermal skin tests.

    Science.gov (United States)

    Mueller, R S; Bettenay, S V; Tideman, L

    2000-06-01

    To determine the most relevant aero-allergens involved in canine atopic dermatitis in southeastern Australia and provide information about these aero-allergens to the general practitioner. Dogs presented to the Animal Skin & Allergy Clinic with history and clinical signs of atopic dermatitis were injected intradermally with 38 different allergens and negative and positive control. Intradermal skin tests in 1000 dogs were retrospectively evaluated. One third of all patients reacted to the house dust mite Dermatophagoides farinae. Allergens reacting in more than 15% of the patients were wheat (Triticum aestivum), sweet vernal (Anthoxanthum odoratum), English couch (Agropyron repens), yellow dock (Rumex crispus), Mexican tea (Chenopodium ambrosioides), plantain (Plantago lanceolata), melaleuca (Melaleuca quinquenervia) and peppercorn (Schimus spp). House dust mites are the most common allergens in canine atopic dermatitis in southeastern Australia and D farinae is involved most frequently. However, a number of grass, weed and tree pollens also are involved regularly.

  11. Large Wind Turbine Rotor Design using an Aero-Elastic / Free-Wake Panel Coupling Code

    Science.gov (United States)

    Sessarego, Matias; Ramos-García, Néstor; Shen, Wen Zhong; Nørkær Sørensen, Jens

    2016-09-01

    Despite the advances in computing resources in the recent years, the majority of large wind-turbine rotor design problems still rely on aero-elastic codes that use blade element momentum (BEM) approaches to model the rotor aerodynamics. The present work describes an approach to wind-turbine rotor design by incorporating a higher-fidelity free-wake panel aero-elastic coupling code called MIRAS-FLEX. The optimization procedure includes a series of design load cases and a simple structural design code. Due to the heavy MIRAS-FLEX computations, a surrogate-modeling approach is applied to mitigate the overall computational cost of the optimization. Improvements in cost of energy, annual energy production, maximum flap-wise root bending moment, and blade mass were obtained for the NREL 5MW baseline wind turbine.

  12. Aero-thermo-dynamic analysis of a low ballistic coefficient deployable capsule in Earth re-entry

    Science.gov (United States)

    Zuppardi, G.; Savino, R.; Mongelluzzo, G.

    2016-10-01

    The paper deals with a microsatellite and the related deployable recovery capsule. The aero-brake is folded at launch and deployed in space and is able to perform a de-orbiting controlled re-entry. This kind of capsule, with a flexible, high temperature resistant fabric, thanks to its lightness and modulating capability, can be an alternative to the current "conventional" recovery capsules. The present authors already analyzed the trajectory and the aerodynamic behavior of low ballistic coefficient capsules during Earth re-entry and Mars entry. In previous studies, aerodynamic longitudinal stability analysis and evaluation of thermal and aerodynamic loads for a possible suborbital re-entry demonstrator were carried out in both continuum and rarefied regimes. The present study is aimed at providing preliminary information about thermal and aerodynamic loads and longitudinal stability for a similar deployable capsule, as well as information about the electronic composition of the plasma sheet and its possible influence on radio communications at the altitudes where GPS black-out could occur. Since the computer tests were carried out at high altitudes, therefore in rarefied flow fields, use of Direct Simulation Monte Carlo codes was mandatory. The computations involved both global aerodynamic quantities (drag and longitudinal moment coefficients) and local aerodynamic quantities (heat flux and pressure distributions along the capsule surface). The results verified that the capsule at high altitude (150 km) is self-stabilizing; it is stable around the nominal attitude or at zero angle of attack and unstable around the reverse attitude or at 180° angle of attack. The analysis also pointed out the presence of extra statically stable equilibrium trim points.

  13. Influence of electrical parameters on H2O2 generation in DBD non-thermal reactor with water mist

    Science.gov (United States)

    Xu, Di; Xiao, Zehua; Hao, Chunjing; Qiu, Jian; Liu, Kefu

    2017-06-01

    A dielectric barrier discharge (DBD) reactor is introduced to generate H2O2 by non-thermal plasma with a mixture of oxygen and water mist produced by an ultrasonic atomizer. The results of our experiment show that the energy yield and concentration of the generated H2O2 in the pulsed discharge are much higher than that in AC discharge, due to its high energy efficiency and low heating effect. Micron-sized liquid droplets produced by an ultrasonic atomizer in water mist have large specific surface area, which greatly reduces mass transfer resistance between hydroxyl radicals and water liquids, leading to higher energy yield and H2O2 concentration than in our previous research. The influence of applied voltage, discharge frequency, and environmental temperature on the generated H2O2 is discussed in detail from the viewpoint of the DBD mechanism. The H2O2 concentration of 30 mg l-1, with the energy yield of 2 g kW-1h-1 is obtained by pulsed discharge in our research.

  14. Optical parameters of ternary Te15(Se100-xBix)85 thin films deposited by thermal evaporation

    Science.gov (United States)

    Kumar, Kameshwar; Sharma, Pankaj; Katyal, S. C.; Thakur, Nagesh

    2011-10-01

    Thin films of Te15(Se100-xBix)85 (x=0, 1, 2, 3, 4 and 5 at.%) glassy alloys were deposited by thermal evaporation (at 10-4 Pa) from bulk samples. Optical characterization of the films was done by analysing their transmission spectra taken in the spectral range 400-2300 nm. Swanepoel's method was used to calculate the refractive index (n) and extinction coefficient (k). It was found that the refractive index increases with an increase in Bi content. The Wemple-DiDomenico single-oscillator approach was used to calculate the average band gap energy (Eo), dispersion energy (Ed) and static refractive index (no). The absorption coefficient (α) and film thickness were calculated from the transmission spectra of the films. The optical band gap (Eg) was estimated using Tauc's extrapolation and was found to decrease from 1.37 to 1.21 eV with Bi addition from 0 to 5 at.% in glassy alloys. The decrease in optical band gap is explained on the basis of the decrease in cohesive energy of the samples and the difference of electronegativity of the atoms involved. The real (ɛr) and imaginary parts (ɛi) of the dielectric constant for the films were also calculated and reported.

  15. Pyrolysis of Pinus pinaster in a two-stage gasifier: Influence of processing parameters and thermal cracking of tar

    Energy Technology Data Exchange (ETDEWEB)

    Fassinou, Wanignon Ferdinand; Toure, Siaka [Laboratoire d' Energie Solaire-UFR-S.S.M.T. Universite de Cocody, 22BP582 Abidjan 22 (Ivory Coast); Van de Steene, Laurent; Volle, Ghislaine; Girard, Philippe [CIRAD-Foret, TA 10/16, 73, avenue J.-F. Breton, 34398 Montpellier, Cedex 5 (France)

    2009-01-15

    A new two-stage gasifier with fixed-bed has recently been installed on CIRAD facilities in Montpellier. The pyrolysis and the gasifier units are removable. In order to characterise the pyrolysis products before their gasification, experiments were carried out, for the first time only with the pyrolysis unit and this paper deals with the results obtained. The biomass used is Pinus pinaster. The parameters investigated are: temperature, residence time and biomass flow rate. It has been found that increasing temperature and residence time improve the cracking of tars, gas production and char quality (fixed carbon rate more than 90%, volatile matter rate less than 4%). The increase of biomass flow rate leads to a bad char quality. The efficiency of tar cracking, the quality and the heating value of the charcoal and the gases, indicate that: temperature between 650 C and 750 C, residence time of 30 min, biomass flow rate between 10 and 15 kg/h should be the most convenient experimental conditions to get better results from the experimental device and from the biomass pyrolysis process. The kinetic study of charcoal generation shows that the pyrolysis process, in experimental conditions, is a first-order reaction. The kinetic parameters calculated are comparable with those found by other researchers. (author)

  16. [Aerobic and aero-anaerobic bacterial flora of the nasal cavities of lambs].

    Science.gov (United States)

    Menoueri, N; Richard, Y; Brunet, J; Oudar, J

    1988-01-01

    On the basis of bacteriological examinations carried out on 415 intranasal swabs, aerobic and aero-anaerobic respiratory microbes were studied in lambs. A great diversity of bacteria has been found (in total 35 bacterial species and genus have been identified). This flora is characterised by the presence of gram positive cocci with a gram negative strain included in genus Moraxella and connected with Moraxella bovis species.

  17. Aero-elastic stability of airfoil flow using 2-D CFD

    Energy Technology Data Exchange (ETDEWEB)

    Johansen, J. [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    A three degrees-of-freedom structural dynamics model has been coupled to a two-dimensional incompressible CFD code. The numerical investigation considers aero-elastic stability for two different airfoils; the NACA0012 and the LM 2 18 % airfoils. Stable and unstable configurations and limit cycle oscillations are predicted in accordance with literature for the first airfoil. An attempt to predict stall induced edge-wise vibrations on a wind turbine airfoil fails using this two-dimensional approach. (au)

  18. Integrated Line-of-Sight Modeling of the Airborne Aero-Optics Laboratory

    Science.gov (United States)

    2013-09-01

    compensator. The PID coefficients were adjusted to match the measured behavior. The measured and tuned results are shown in Fig. 6. Measured Tuned ...strain energy in the bond between them. As with the measured data, this mode is destabilized in the tuned model as shown in Figure 6 with the PID ...uncertainty with model tuning based on available experimental measurements was examined for one flight condition. 2. INTRODUCTION The Airborne Aero

  19. Aero-/hydro-elastic stability of flexible panels: Prediction and control using localised spring support

    Science.gov (United States)

    Tan, B. H.; Lucey, A. D.; Howell, R. M.

    2013-12-01

    We study the effect of adding localised stiffness, via a spring support, on the stability of flexible panels subjected to axial uniform incompressible flow. Applications are considered that range from the hydro-elasticity of hull panels of high-speed ships to the aero-elasticity of glass panels in the curtain walls of high-rise buildings in very strong winds. A two-dimensional linear analysis is conducted using a hybrid of theoretical and computational methods that calculates the system eigen-states but can also be used to capture the transient behaviour that precedes these. We show that localised stiffening is a very effective means to increase the divergence-onset flow speed in both hydro- and aero-elastic applications. It is most effective when located at the mid-chord of the panel and there exists an optimum value of added stiffness beyond which further increases to the divergence-onset flow speed do not occur. For aero-elastic applications, localised stiffening can be used to replace the more destructive flutter instability that follows divergence at higher flow speeds by an extended range of divergence. The difference in eigen-solution morphology between aero- and hydro-elastic applications is highlighted, showing that for the former coalescence of two non-oscillatory divergence modes is the mechanism for flutter onset. This variation in solution morphology is mapped out in terms of a non-dimensional mass ratio. Finally, we present a short discussion of the applicability of the stabilisation strategy in a full three-dimensional system.

  20. Effect of manufacturing parameters on TBC systems cyclic oxidation lifetime

    OpenAIRE

    Chirivi, Laura

    2011-01-01

    Aero-gas turbine engines have to meet reliability, durability and fuel e ciency requirements. High turbine inlet temperatures may contribute to minimise fuel consumption and, in turn, environmental impact of the engine. Over the past few years, new designs and engine optimisation have allowed increase of such temperatures at a rate of 15 C per year, with maximum operating temperatures currently exceeding 1650 C. Ceramic coatings (also known as Thermal Barrier Coatings or TBCs) ...

  1. A comparison between different finite elements for elastic and aero-elastic analyses.

    Science.gov (United States)

    Mahran, Mohamed; ELsabbagh, Adel; Negm, Hani

    2017-11-01

    In the present paper, a comparison between five different shell finite elements, including the Linear Triangular Element, Linear Quadrilateral Element, Linear Quadrilateral Element based on deformation modes, 8-node Quadrilateral Element, and 9-Node Quadrilateral Element was presented. The shape functions and the element equations related to each element were presented through a detailed mathematical formulation. Additionally, the Jacobian matrix for the second order derivatives was simplified and used to derive each element's strain-displacement matrix in bending. The elements were compared using carefully selected elastic and aero-elastic bench mark problems, regarding the number of elements needed to reach convergence, the resulting accuracy, and the needed computation time. The best suitable element for elastic free vibration analysis was found to be the Linear Quadrilateral Element with deformation-based shape functions, whereas the most suitable element for stress analysis was the 8-Node Quadrilateral Element, and the most suitable element for aero-elastic analysis was the 9-Node Quadrilateral Element. Although the linear triangular element was the last choice for modal and stress analyses, it establishes more accurate results in aero-elastic analyses, however, with much longer computation time. Additionally, the nine-node quadrilateral element was found to be the best choice for laminated composite plates analysis.

  2. Mode shape description of an aero-engine casing structure using Zernike moment descriptors

    Institute of Scientific and Technical Information of China (English)

    LIU Ying-chao; ZANG Chao-ping

    2011-01-01

    Vibration mode shape description of an aero-engine casing structure using Zernike moment descriptor (ZMD) was introduced in this paper. The mode shapes of the aero-engine casing structure can be decomposed as a linear combination of a series of Zernike polynomials, with the feature of each Zernike polynomial reflecting a part of characteristic of mode shapes, based on Zernike moment transformation. Meanwhile, the reconstruction of mode shapes with ZMD was explored and its ability to filtering the noise contaminated in the mode shapes was studied. Simulation of the aero-engine casing structure indicated the advantage of this method to depict the mode shapes of a symmetric structure. Results demonstrate that the Zernike moment description of the mode shapes can effectively describe the double modes in the symmetric structure and also has the ability to remove or significantly reduce the influence of noise in the mode shapes. Such feature shows great practical value for further research on the correlation, model updating and model validation of the symmetric structure's finite element model.

  3. RANDOM-FUZZY SAFETY ANALYSIS FOR AN AERO ENGINE TURBINE DISK

    Institute of Scientific and Technical Information of China (English)

    Z.Z. Lü; C.L. Liu; Y.L. Xu; Z.F. Yue

    2004-01-01

    A numerical simulation method is presented for the random-fuzzy safety analysis of an aero engine disk. Based on the equivalent transformation from a fuzzy variable to a random variable, the equivalent random Probability Density Functions(PDFs)are got from their corresponding Fuzzy Possibility Distributions(FPDs) for the fuzzy variables. In that case the perfect numerical simulation method for the random uncertainty is employed to solve the fuzzy uncertainty. For the complex structure such as the aero engine disk with implicit relationship between the input basic variable and the response variable, the equivalent PDFs of the input basic variables are delivered simultaneously to the response variable by an empirical PDF, which is simulated by Finite Element Method(FEM). Then, in view of the fuzzy application requirement occurring in engineering usually, the reliability definition and calculation are discussed for the aero engine disk with multiple fuzzy failure modes. On the other hand, through the inverse transformation of the fuzzy variable to the random variable, the FPDs of the response variables can be calculated from their empirical PDFs as well.

  4. The evaluation of the influence of laser treatment parameters on the type of thermal effects in the surface layer microstructure of gray irons

    Science.gov (United States)

    Paczkowska, Marta

    2016-01-01

    The aim of the presented research was to create a laser heat treatment (LHT) diagram presenting singular modifications such as remelting, alloying, hardening from the solid state, tempering the surface layer of gray iron in individual ranges of laser beam parameters (power density and its interaction time). A synthesis of such different thermal phenomena taking place in gray irons surface layer resulting from LHT was the aim of this analysis. The performed research allowed specifying similar, previously created diagrams concerning different engineering materials in general. The created LHT diagram presents singular modifications in the surface layer of gray iron in individual ranges of laser beam parameters. This diagram allows distinguishing ranges of laser beam parameters that could be useful in selecting the LHT parameters or forecasting their effects in the gray iron surface layer. It has been observed that it is possible to achieve the modification of the surface layer of gray iron by applying values of laser beam power density lower than the values of density presented in previously created diagrams related to the influence of LHT parameters on their effects in the surface layer referring to different groups of engineering materials. The limit of the laser beam density was defined resulting in the modification of the surface layer for interaction time t0.2 s (hardening from the solid state). It is not possible to achieve melting or hardening of the surface layer in gray irons using a laser beam density of less than 10 W mm-2. Hardening is possible only with the interaction time longer than 0.2 s and the power beam density between 10 and 40 W mm-2. Tempering of the surface layer is possible with the density of nearly 10 W mm-2 but only with a relatively long interaction time (i.e. 4 s).

  5. The effect of harmonized emissions on aerosol properties in global models – an AeroCom experiment

    Directory of Open Access Journals (Sweden)

    C. Textor

    2007-08-01

    Full Text Available The effects of unified aerosol sources on global aerosol fields simulated by different models are examined in this paper. We compare results from two AeroCom experiments, one with different (ExpA and one with unified emissions, injection heights, and particle sizes at the source (ExpB. Surprisingly, harmonization of aerosol sources has only a small impact on the simulated inter-model diversity of the global aerosol burden, and consequently global optical properties, as the results are largely controlled by model-specific transport, removal, chemistry (leading to the formation of secondary aerosols and parameterizations of aerosol microphysics (e.g., the split between deposition pathways and to a lesser extent by the spatial and temporal distributions of the (precursor emissions.

    The burdens of black carbon and especially sea salt become more coherent in ExpB only, because the large ExpA diversities for these two species were caused by a few outliers. The experiment also showed that despite prescribing emission fluxes and size distributions, ambiguities in the implementation in individual models can lead to substantial differences.

    These results indicate the need for a better understanding of aerosol life cycles at process level (including spatial dispersal and interaction with meteorological parameters in order to obtain more reliable results from global aerosol simulations. This is particularly important as such model results are used to assess the consequences of specific air pollution abatement strategies.

  6. Physical model of granule adhesion to the belt-electrodes of a tribo-aero-electrostatic separator

    Science.gov (United States)

    Li, Jia; Dascalescu, Lucian; Miloudi, Mohamed; Bilici, Mihai; Xu, Zhenming

    2013-03-01

    Recent studies have demonstrated the effectiveness of tribo-aero-electrostatic separation technologies, which consist in the selective sorting of mixed granular insulating materials in a fluidized bed affected by an electric field orthogonally oriented to the direction of the fluidization air. The aim of the present paper is to put the theoretical bases for the optimization of this process, i. e. maximize the total mass of the granules collected at the two electrodes that generate the electric field. The various forces that drive a granule of given mass and electric charge through the electric field and make it stick to an electrode are expressed as functions of the several input variables and parameters of the process, such as the applied high-voltage or the surface roughness, the size and the position of the electrodes. The concepts of "critical electrostatic field" and "virtual climbing distance" are introduced. The prediction of the theoretical model are confirmed by the results of three sets of experiments, carried out on samples of a granular mixture consisting of 50% Acrylonitrile Butadiene Styrene (ABS) and 50% High Impact Polystyrene (HIPS), originating from the recycling of waste electric and electronic equipment. Higher separation efficiency was obtained when the electric field in the active zone was intensified by the use of an additional electrode connected to the ground and when the collecting electrodes were covered by a thin insulating layer.

  7. Concurrent identification of aero-acoustic scattering and noise sources at a flow duct singularity in low Mach number flow

    Science.gov (United States)

    Sovardi, Carlo; Jaensch, Stefan; Polifke, Wolfgang

    2016-09-01

    A numerical method to concurrently characterize both aeroacoustic scattering and noise sources at a duct singularity is presented. This approach combines Large Eddy Simulation (LES) with techniques of System Identification (SI): In a first step, a highly resolved LES with external broadband acoustic excitation is carried out. Subsequently, time series data extracted from the LES are post-processed by means of SI to model both acoustic propagation and noise generation. The present work studies the aero-acoustic characteristics of an orifice placed in a duct at low flow Mach numbers with the "LES-SI" method. Parametric SI based on the Box-Jenkins mathematical structure is employed, with a prediction error approach that utilizes correlation analysis of the output residuals to avoid overfitting. Uncertainties of model parameters due to the finite length of times series are quantified in terms of confidence intervals. Numerical results for acoustic scattering matrices and power spectral densities of broad-band noise are validated against experimental measurements over a wide range of frequencies below the cut-off frequency of the duct.

  8. Respiratory complaints and spirometric parameters of the villagers living around the Seyitomer coal-fired thermal power plant in Kutahya, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Karavus, M.; Aker, A.; Cebeci, D.; Tasdemir, M.; Bayram, N.; Cali, S. [University of Marmara, Istanbul (Turkey). School of Medicine, Dept. of Public Health

    2002-07-01

    The respiratory effects of the stack emissions of the Seyitomer coal-fired thermal power plant in the Kutahya Province of Turkey were investigated. Three villages within 5 km of the power plant were investigated as 'Villages around Power Plant.' Two similar villages more than 30 km away were investigated as 'Control Villages.' The study compared respiratory complaints and the spirometric parameters of the individuals living in the two groups of villages. It was carried out on individuals of 15 years of age and above living in these villages (277 of 302 individuals living in the Villages around Power Plant and 225 of 264 living in the Control Villages). Among the ones living in the Villages around Power Plant, 46.2% had complaints of chest tightness and 29.2% repeated coughing attacks present for more than one year, whereas these percentages were 28.0 and 20.4% in the Control Villages. The means of the spirometric parameters of FEV1 and FEF25-75% were found to be statistically significantly lower in the individuals of the Villages around Power Plant compared to the individuals of the Control Villages. The spirometric parameters revealed statistically significant adverse health effects of the Power Plant. This was particularly apparent for the nonsmokers. More specific tests to confirm the diagnosis of acute and chronic lung diseases could be carried out.

  9. Effect of Welding Parameters on Microstructure, Thermal, and Mechanical Properties of Friction-Stir Welded Joints of AA7075-T6 Aluminum Alloy

    Science.gov (United States)

    Lotfi, Amir Hossein; Nourouzi, Salman

    2014-06-01

    A high-strength Al-Zn-Mg-Cu alloy AA7075-T6 was friction-stir welded with various process parameter combinations incorporating the design of the experiment to investigate the effect of welding parameters on the microstructure and mechanical properties. A three-factors, five-level central composition design (CCD) has been used to minimize the number of experimental conditions. The friction-stir welding parameters have significant influence on the heat input and temperature profile, which in turn regulates the microstructural and mechanical properties of the joints. The weld thermal cycles and transverse distribution of microhardness of the weld joints were measured, and the tensile properties were tested. The fracture surfaces of tensile specimens were observed by a scanning electron microscope (SEM), and the formation of friction-stir processing zone has been analyzed macroscopically. Also, an equation was derived to predict the final microhardness and tensile properties of the joints, and statistical tools are used to develop the relationships. The results show that the peak temperature during welding of all the joints was up to 713 K (440 °C), which indicates the key role of the tool shoulder diameter in deciding the maximum temperature. From this investigation, it was found that the joint fabricated at a rotational speed of 1050 rpm, welding speed of 100 mm/min, and shoulder diameter of 14 mm exhibited higher mechanical properties compared to the other fabricated joints.

  10. Influence of Envelope Thermal Parameter on Indoor Thermal Load Calculations of Public Buildings%公共建筑围护结构热工参数取值对暖通负荷计算的影响分析

    Institute of Scientific and Technical Information of China (English)

    吴晓晨

    2014-01-01

    In the process of building design, indoor thermal load are calculated simultaneously with building envelope thermal parameters, which results in the absence of actual envelope thermal properties in the load calculation. The influence of referring limit value from related codes is evaluated in this scenario. The result shows that the difference between the actual thermal properties is minor in most of buildings in-vested. The error of indoor thermal load caused by using limit value basically does not impact the equip-ment selection. It is proved that the method of using limit value is feasible when actual properties are un-known at the moment.%设计过程中,暖通专业负荷计算与建筑专业围护结构节能计算通常是同时进行的,因此,负荷计算时普遍缺少围护结构热工参数。如果此时热工参数参照国家或地方标准中给定的规定性指标选取,则暖通专业负荷计算结果与实际负荷可能会存在一定偏差。采用案例分析法,判断了此类负荷计算偏差是否会影响采暖空调设备选型。结果发现,对于绝大多数建筑而言,其围护结构实际的热工参数都比较接近标准限值,而因此造成的暖通负荷计算偏差也较小。在缺乏实际围护结构热工参数的情况下,使用规定性限值计算冷热负荷的方法是可行的。并研究探讨了此类偏差与建筑类型、面积以及所在地区等关系,对设计过程中的负荷计算提出了相应的建议。

  11. Thermal X-Ray Emission from Shocked Ejecta in Type Ia Supernova Remnants II: Parameters Affecting the Spectrum

    CERN Document Server

    Badenes, C; Bravo, E

    2005-01-01

    The supernova remnants left behind by Type Ia supernovae provide an excellent opportunity for the study of these enigmatic objects. In a previous work, we showed that it is possible to use the X-ray spectra of young Type Ia supernova remnants to explore the physics of Type Ia supernovae and identify the relevant mechanism underlying these explosions. Our simulation technique is based on hydrodynamic and nonequilibrium ionization calculations of the interaction of a grid of Type Ia explosion models with the surrounding ambient medium, coupled to an X-ray spectral code. In this work we explore the influence of two key parameters on the shape of the X-ray spectrum of the ejecta: the density of the ambient medium around the supernova progenitor and the efficiency of collisionless electron heating at the reverse shock. We also discuss the performance of recent 3D simulations of Type Ia SN explosions in the context of the X-ray spectra of young SNRs. We find a better agreement with the observations for Type Ia supe...

  12. Modeling and Characteristic Parameters Analysis of a Trough Concentrating Photovoltaic/Thermal System with GaAs and Super Cell Arrays

    Directory of Open Access Journals (Sweden)

    Xu Ji

    2012-01-01

    Full Text Available The paper established the one-dimension steady models of a trough concentrating photovoltaic/thermal system with a super cell array and a GaAs cell array, respectively, and verified the models by experiments. The gaps between calculation results and experimental results were less than 5%. Utilizing the models, the paper analyzed the influences of the characteristic parameters on the performances of the TCPV/T system with a super cell array and a GaAs cell array, respectively. The reflectivity of the parabolic mirror in the TCPV/T system was an important factor to determine the utilizing efficiency of solar energy. The performances of the TCPV/T system can be optimized by improving the mirror reflectivity and the thermal solar radiation absorptivity of the lighting plate and pursuing a suitable focal line with uniform light intensity distribution. All these works will benefit to the utilization of the trough concentrating system and the combined heat/power supply.

  13. Do Lumped-Parameter Models Provide the Correct Geometrical Damping?

    DEFF Research Database (Denmark)

    Andersen, Lars

    This paper concerns the formulation of lumped-parameter models for rigid footings on homogenous or stratified soil. Such models only contain a few degrees of freedom, which makes them ideal for inclusion in aero-elastic codes for wind turbines and other models applied to fast evaluation of struct......This paper concerns the formulation of lumped-parameter models for rigid footings on homogenous or stratified soil. Such models only contain a few degrees of freedom, which makes them ideal for inclusion in aero-elastic codes for wind turbines and other models applied to fast evaluation...... response during excitation and the geometrical damping related to free vibrations of a hexagonal footing. The optimal order of a lumped-parameter model is determined for each degree of freedom, i.e. horizontal and vertical translation as well as torsion and rocking. In particular, the necessity of coupling...... between horizontal sliding and rocking is discussed....

  14. Solar Tower Experiments for Radiometric Calibration and Validation of Infrared Imaging Assets and Analysis Tools for Entry Aero-Heating Measurements

    Science.gov (United States)

    Splinter, Scott C.; Daryabeigi, Kamran; Horvath, Thomas J.; Mercer, David C.; Ghanbari, Cheryl M.; Ross, Martin N.; Tietjen, Alan; Schwartz, Richard J.

    2008-01-01

    The NASA Engineering and Safety Center sponsored Hypersonic Thermodynamic Infrared Measurements assessment team has a task to perform radiometric calibration and validation of land-based and airborne infrared imaging assets and tools for remote thermographic imaging. The IR assets and tools will be used for thermographic imaging of the Space Shuttle Orbiter during entry aero-heating to provide flight boundary layer transition thermography data that could be utilized for calibration and validation of empirical and theoretical aero-heating tools. A series of tests at the Sandia National Laboratories National Solar Thermal Test Facility were designed for this task where reflected solar radiation from a field of heliostats was used to heat a 4 foot by 4 foot test panel consisting of LI 900 ceramic tiles located on top of the 200 foot tall Solar Tower. The test panel provided an Orbiter-like entry temperature for the purposes of radiometric calibration and validation. The Solar Tower provided an ideal test bed for this series of radiometric calibration and validation tests because it had the potential to rapidly heat the large test panel to spatially uniform and non-uniform elevated temperatures. Also, the unsheltered-open-air environment of the Solar Tower was conducive to obtaining unobstructed radiometric data by land-based and airborne IR imaging assets. Various thermocouples installed on the test panel and an infrared imager located in close proximity to the test panel were used to obtain surface temperature measurements for evaluation and calibration of the radiometric data from the infrared imaging assets. The overall test environment, test article, test approach, and typical test results are discussed.

  15. The use of a directional solidification technique to investigate the interrelationship of thermal parameters, microstructure and microhardness of Bi–Ag solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Spinelli, José Eduardo, E-mail: spinelli@ufscar.br [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil); Silva, Bismarck Luiz [Department of Materials Engineering, Federal University of São Carlos, UFSCar, 13565-905 São Carlos, SP (Brazil); Cheung, Noé; Garcia, Amauri [Department of Manufacturing and Materials Engineering, University of Campinas, UNICAMP, PO Box 6122, 13083-970 Campinas, SP (Brazil)

    2014-10-15

    Bi–Ag alloys have been stressed as possible alternatives to replace Pb-based solder alloys. Although acceptable melting temperatures and suitable mechanical properties may characterize such alloys, as referenced in literature, there is a lack of comprehension regarding their microstructures (morphologies and sizes of the phases) considering a composition range from 1.5 to 4.0 wt.%Ag. In order to better comprehend such aspects and their correlations with solidification thermal parameters (growth rate, v and cooling rate, T-dot), directional solidification experiments were carried out under transient heat flow conditions. The effects of Ag content on both cooling rate and growth rate during solidification are examined. Microstructure parameters such as eutectic/dendritic spacing, interphase spacing and diameter of the Ag-rich phase were determined by optical microscopy and scanning electron microscopy. The competition between eutectic cells and dendrites in the range from 1.5 to 4.0 wt.%Ag is explained by the coupled zone concept. Microhardness was determined for different microstructures and alloy Ag contents with a view to permitting correlations with microstructure parameters to be established. Hardness is shown to be directly affected by both solute macrosegregation and morphologies of the phases forming the Bi–Ag alloys, with higher hardness being associated with the cellular morphology of the Bi-2.5 and 4.0 wt.%Ag alloys. - Highlights: • Asymmetric zone of coupled growth for Bi–Ag is demonstrated. • Faceted Bi-rich dendrites have been characterized for Bi–1.5 wt.%Ag alloy. • Eutectic cells were shown for the Bi-2.5 and 4.0 wt.%Ag solder alloys. • Interphase spacing relations with G × v are able to represent the experimental scatters. • Hall-Petch type equations are proposed relating microstructural spacings to hardness.

  16. Nonlinear and chaotic vibration and stability analysis of an aero-elastic piezoelectric FG plate under parametric and primary excitations

    Science.gov (United States)

    Rezaee, Mousa; Jahangiri, Reza

    2015-05-01

    In this study, in the presence of supersonic aerodynamic loading, the nonlinear and chaotic vibrations and stability of a simply supported Functionally Graded Piezoelectric (FGP) rectangular plate with bonded piezoelectric layer have been investigated. It is assumed that the plate is simultaneously exposed to the effects of harmonic uniaxial in-plane force and transverse piezoelectric excitations and aerodynamic loading. It is considered that the potential distribution varies linearly through the piezoelectric layer thickness, and the aerodynamic load is modeled by the first order piston theory. The von-Karman nonlinear strain-displacement relations are used to consider the geometrical nonlinearity. Based on the Classical Plate Theory (CPT) and applying the Hamilton's principle, the nonlinear coupled partial differential equations of motion are derived. The Galerkin's procedure is used to reduce the equations of motion to nonlinear ordinary differential Mathieu equations. The validity of the formulation for analyzing the Limit Cycle Oscillation (LCO), aero-elastic stability boundaries is accomplished by comparing the results with those of the literature, and the convergence study of the FGP plate is performed. By applying the Multiple Scales Method, the case of 1:2 internal resonance and primary parametric resonance are taken into account and the corresponding averaged equations are derived and analyzed numerically. The results are provided to investigate the effects of the forcing/piezoelectric detuning parameter, amplitude of forcing/piezoelectric excitation and dynamic pressure, on the nonlinear dynamics and chaotic behavior of the FGP plate. It is revealed that under the certain conditions, due to the existence of bi-stable region of non-trivial solutions, system shows the hysteretic behavior. Moreover, in absence of airflow, it is observed that variation of control parameters leads to the multi periodic and chaotic motions.

  17. A semi-quantitative risk assessment method for analyzing the level of risk associated with parameters in design of thermal heavy oil Steam Assisted Gravity Drainage (SAGD) pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Farrokhzad, M.A. [IMV Projects Inc., Alberta (Canada)

    2009-07-01

    During the design stage of a thermal heavy oil pipeline, the design engineer should include the consideration of more factors than what is normally used for the design of a conventional pipeline. In the Steam Assisted Gravity Drainage (SAGD) production, for the extraction of bitumen from oily soil, it is required that a stream of hot and pressurized steam (over 300 deg C) to be injected into the oil reservoir. The steam reaches the oily soil reservoir from a steam sour such as boilers by traveling through above-ground pipeline arrangements. As a result of the steam injection into the well site, bitumen oil is released from the oily soil. The produced bitumen also consists of high pressure and temperature (over 200 deg C) and requires a gathering pipeline arrangement for traveling to the processing plant. During the layout design, both steam injection and hot production lines are usually designed parallel with each other by using a series of anchor-loop-anchor supported by steel structures and pilings. The coexistence of two extremely hot pipelines (Injecting Steam and Production pipelines) on the aboveground pipe rack should be designed with extreme care. The higher than normal design temperature of these lines creates considerable lateral and longitudinal movements and heavy loads on the supporting structure and piling. In addition, since both lines contain high pressure mediums, the design engineer shall include a few more parameters than what is normally considered for conventional pipelines. These parameters include; sustain loads, slug forces, natural frequency, mechanical interactions, frictional forces on anchors and guides, and mechanical engagement of supporting components, as well as the effects of these loads on the steel structure-piling and their reaction with the surrounding soil. In addition the design engineer shall be aware of any potential failures associated with these physical and mechanical parameters, the impact and probability rationales and

  18. Aero Engine Fault Diagnosis Using an Optimized Extreme Learning Machine

    Directory of Open Access Journals (Sweden)

    Xinyi Yang

    2016-01-01

    Full Text Available A new extreme learning machine optimized by quantum-behaved particle swarm optimization (QPSO is developed in this paper. It uses QPSO to select optimal network parameters including the number of hidden layer neurons according to both the root mean square error on validation data set and the norm of output weights. The proposed Q-ELM was applied to real-world classification applications and a gas turbine fan engine diagnostic problem and was compared with two other optimized ELM methods and original ELM, SVM, and BP method. Results show that the proposed Q-ELM is a more reliable and suitable method than conventional neural network and other ELM methods for the defect diagnosis of the gas turbine engine.

  19. Real-time analysis of ambient organic aerosols using aerosol flowing atmospheric-pressure afterglow mass spectrometry (AeroFAPA-MS)

    Science.gov (United States)

    Brüggemann, Martin; Karu, Einar; Stelzer, Torsten; Hoffmann, Thorsten

    2015-04-01

    Organic aerosol accounts for a major fraction of atmospheric aerosols and has implications on the earth's climate and human health. However, due to the chemical complexity its measurement remains a major challenge for analytical instrumentation.1 Here, we present the development, characterization and application of a new soft ionization technique that allows mass spectrometric real-time detection of organic compounds in ambient aerosols. The aerosol flowing atmospheric-pressure afterglow (AeroFAPA) ion source utilizes a helium glow discharge plasma to produce excited helium species and primary reagent ions. Ionization of the analytes occurs in the afterglow region after thermal desorption and results mainly in intact molecular ions, facilitating the interpretation of the acquired mass spectra. In the past, similar approaches were used to detect pesticides, explosives or illicit drugs on a variety of surfaces.2,3 In contrast, the AeroFAPA source operates 'online' and allows the detection of organic compounds in aerosols without a prior precipitation or sampling step. To our knowledge, this is the first application of an atmospheric-pressure glow discharge ionization technique to ambient aerosol samples. We illustrate that changes in aerosol composition and concentration are detected on the time scale of seconds and in the ng-m-3 range. Additionally, the successful application of AeroFAPA-MS during a field study in a mixed forest region in Central Europe is presented. Several oxidation products of monoterpenes were clearly identified using the possibility to perform tandem MS experiments. The acquired data are in agreement with previous studies and demonstrate that AeroFAPA-MS is a suitable tool for organic aerosol analysis. Furthermore, these results reveal the potential of this technique to enable new insights into aerosol formation, growth and transformation in the atmosphere. References: 1) IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The

  20. AeroCom INSITU Project: Comparing modeled and measured aerosol optical properties

    Science.gov (United States)

    Andrews, Elisabeth; Schmeisser, Lauren; Schulz, Michael; Fiebig, Markus; Ogren, John; Bian, Huisheng; Chin, Mian; Easter, Richard; Ghan, Steve; Kokkola, Harri; Laakso, Anton; Myhre, Gunnar; Randles, Cynthia; da Silva, Arlindo; Stier, Phillip; Skeie, Ragnehild; Takemura, Toshihiko; van Noije, Twan; Zhang, Kai

    2016-04-01

    AeroCom, an open international collaboration of scientists seeking to improve global aerosol models, recently initiated a project comparing model output to in-situ, surface-based measurements of aerosol optical properties. The model/measurement comparison project, called INSITU, aims to evaluate the performance of a suite of AeroCom aerosol models with site-specific observational data in order to inform iterative improvements to model aerosol modules. Surface in-situ data has the unique property of being traceable to physical standards, which is an asset in accomplishing the overall goal of bettering the accuracy of aerosols processes and the predicative capability of global climate models. Here we compare dry, in-situ aerosol scattering and absorption data from ~75 surface, in-situ sites from various global aerosol networks (including NOAA, EUSAAR/ACTRIS and GAW) with a simulated optical properties from a suite of models participating in the AeroCom project. We report how well models reproduce aerosol climatologies for a variety of time scales, aerosol characteristics and behaviors (e.g., aerosol persistence and the systematic relationships between aerosol optical properties), and aerosol trends. Though INSITU is a multi-year endeavor, preliminary phases of the analysis suggest substantial model biases in absorption and scattering coefficients compared to surface measurements, though the sign and magnitude of the bias varies with location. Spatial patterns in the biases highlight model weaknesses, e.g., the inability of models to properly simulate aerosol characteristics at sites with complex topography. Additionally, differences in modeled and measured systematic variability of aerosol optical properties suggest that some models are not accurately capturing specific aerosol behaviors, for example, the tendency of in-situ single scattering albedo to decrease with decreasing aerosol extinction coefficient. The endgoal of the INSITU project is to identify specific

  1. Development and Validation of a New Blade Element Momentum Skewed-Wake Model within AeroDyn: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Ning, S. A.; Hayman, G.; Damiani, R.; Jonkman, J.

    2014-12-01

    Blade element momentum methods, though conceptually simple, are highly useful for analyzing wind turbines aerodynamics and are widely used in many design and analysis applications. A new version of AeroDyn is being developed to take advantage of new robust solution methodologies, conform to a new modularization framework for National Renewable Energy Laboratory's FAST, utilize advanced skewed-wake analysis methods, fix limitations with previous implementations, and to enable modeling of highly flexible and nonstraight blades. This paper reviews blade element momentum theory and several of the options available for analyzing skewed inflow. AeroDyn implementation details are described for the benefit of users and developers. These new options are compared to solutions from the previous version of AeroDyn and to experimental data. Finally, recommendations are given on how one might select from the various available solution approaches.

  2. Derivation of Aero-Induced Fluctuating Pressure Environments for Ares I-X

    Science.gov (United States)

    Yang, Michael Y.; Wilby, John F.

    2008-01-01

    A description is given of the external aero-inducted fluctuating pressure model which was fit and anchored to wind tunnel data from the past 40 years. This model is based upon the assumption that the flow around a vehicle can be divided into discrete flow zones with independent fluctuating pressure properties. The model is then used to derive fluctuating pressure environments during ascent for the Ares I-X test vehicle. A sensitivity study of the structural response to the spatial correlation of the fluctuating pressures is also performed.

  3. RELIABILITY ANALYSIS FOR AN AERO ENGINE TURBINE DISK UNDER LOW CYCLE FATIGUE CONDITION

    Institute of Scientific and Technical Information of China (English)

    C.L. Liu; Z.Z. Lü; Y.L. Xu

    2004-01-01

    Reliability analysis methods based on the linear damage accumulation law (LDAL) and load-life interference model are studied in this paper. According to the equal probability rule, the equivalent loads are derived, and the reliability analysis method based on load-life interference model and recurrence formula is constructed. In conjunction with finite element analysis (FEA) program, the reliability of an aero engine turbine disk under low cycle fatigue (LCF) condition has been analyzed. The results show the turbine disk is safety and the above reliability analysis methods are feasible.

  4. Large Wind Turbine Rotor Design using an Aero-Elastic / Free-Wake Panel Coupling Code

    DEFF Research Database (Denmark)

    Sessarego, Matias; Ramos García, Néstor; Shen, Wen Zhong;

    2016-01-01

    Despite the advances in computing resources in the recent years, the majority of large wind-turbine rotor design problems still rely on aero-elastic codes that use blade element momentum (BEM) approaches to model the rotor aerodynamics. The present work describes an approach to wind-turbine rotor...... the overall computational cost of the optimization. Improvements in cost of energy, annual energy production, maximum ap-wise root bending moment, and blade mass were obtained for the NREL 5MW baseline wind turbine....

  5. A novel full scale experimental characterization of wind turbine aero-acoustic noise sources - preliminary results

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Bertagnolio, Franck; Fischer, Andreas;

    2016-01-01

    The paper describes a novel full scale experiment on a 500 kW wind turbine with the main objective to characterize the aero-acoustic noise sources. The idea behind the instrumentation is to study the link and correlation between the surface pressure (SP) fluctuations in the boundary layer...... of the blade and the noise on the ground in a distance of about one rotor diameter. In total six surface microphones were used to measure the SP at the leading edge (LE) and trailing edge (TE) of the blade. In parallel noise was measured by eight microphones placed on plates on the ground around the turbine...

  6. Statistical learning methods for aero-optic wavefront prediction and adaptive-optic latency compensation

    Science.gov (United States)

    Burns, W. Robert

    Since the early 1970's research in airborne laser systems has been the subject of continued interest. Airborne laser applications depend on being able to propagate a near diffraction-limited laser beam from an airborne platform. Turbulent air flowing over the aircraft produces density fluctuations through which the beam must propagate. Because the index of refraction of the air is directly related to the density, the turbulent flow imposes aberrations on the beam passing through it. This problem is referred to as Aero-Optics. Aero-Optics is recognized as a major technical issue that needs to be solved before airborne optical systems can become routinely fielded. This dissertation research specifically addresses an approach to mitigating the deleterious effects imposed on an airborne optical system by aero-optics. A promising technology is adaptive optics: a feedback control method that measures optical aberrations and imprints the conjugate aberrations onto an outgoing beam. The challenge is that it is a computationally-difficult problem, since aero-optic disturbances are on the order of kilohertz for practical applications. High control loop frequencies and high disturbance frequencies mean that adaptive-optic systems are sensitive to latency in sensors, mirrors, amplifiers, and computation. These latencies build up to result in a dramatic reduction in the system's effective bandwidth. This work presents two variations of an algorithm that uses model reduction and data-driven predictors to estimate the evolution of measured wavefronts over a short temporal horizon and thus compensate for feedback latency. The efficacy of the two methods are compared in this research, and evaluated against similar algorithms that have been previously developed. The best version achieved over 75% disturbance rejection in simulation in the most optically active flow region in the wake of a turret, considerably outperforming conventional approaches. The algorithm is shown to be

  7. A Virtual Assembly System for Aero-engines Based on VR

    Institute of Scientific and Technical Information of China (English)

    GAO Ying; GUO Yun-peng; SHAO Ya-nan; XU Zhi-guo

    2008-01-01

    In this paper, a synthesized technique is explored through design of a virtual experiment system for main aeroengine based on VR, which attempts to integrate some VR techniques, such as 3D stereo simulation and modeling, 3D scene management and human-computer virtual assembly based on data glove and collision detection. The geometry modeling and instantiation technique, virtual hand modeling and data glove interaction technique are discussed chiefly. Finally, taking aim at assembling and dismantling experiment system of a certain aero-engine, interface technology is expounded also.

  8. Radiative forcing of the direct aerosol effect from AeroCom Phase II simulations

    Science.gov (United States)

    Myhre, G.; Samset, B. H.; Schulz, M.; Balkanski, Y.; Bauer, S.; Berntsen, T. K.; Bian, H.; Bellouin, N.; Chin, M.; Diehl, T.; Easter, R. C.; Feichter, J.; Ghan, S. J.; Hauglustaine, D.; Iversen, T.; Kinne, S.; Kirkevåg, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Lund, M. T.; Luo, G.; Ma, X.; van Noije, T.; Penner, J. E.; Rasch, P. J.; Ruiz, A.; Seland, Ø.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Wang, P.; Wang, Z.; Xu, L.; Yu, H.; Yu, F.; Yoon, J.-H.; Zhang, K.; Zhang, H.; Zhou, C.

    2013-02-01

    We report on the AeroCom Phase II direct aerosol effect (DAE) experiment where 16 detailed global aerosol models have been used to simulate the changes in the aerosol distribution over the industrial era. All 16 models have estimated the radiative forcing (RF) of the anthropogenic DAE, and have taken into account anthropogenic sulphate, black carbon (BC) and organic aerosols (OA) from fossil fuel, biofuel, and biomass burning emissions. In addition several models have simulated the DAE of anthropogenic nitrate and anthropogenic influenced secondary organic aerosols (SOA). The model simulated all-sky RF of the DAE from total anthropogenic aerosols has a range from -0.58 to -0.02 Wm-2, with a mean of -0.27 Wm-2 for the 16 models. Several models did not include nitrate or SOA and modifying the estimate by accounting for this with information from the other AeroCom models reduces the range and slightly strengthens the mean. Modifying the model estimates for missing aerosol components and for the time period 1750 to 2010 results in a mean RF for the DAE of -0.35 Wm-2. Compared to AeroCom Phase I (Schulz et al., 2006) we find very similar spreads in both total DAE and aerosol component RF. However, the RF of the total DAE is stronger negative and RF from BC from fossil fuel and biofuel emissions are stronger positive in the present study than in the previous AeroCom study. We find a tendency for models having a strong (positive) BC RF to also have strong (negative) sulphate or OA RF. This relationship leads to smaller uncertainty in the total RF of the DAE compared to the RF of the sum of the individual aerosol components. The spread in results for the individual aerosol components is substantial, and can be divided into diversities in burden, mass extinction coefficient (MEC), and normalized RF with respect to AOD. We find that these three factors give similar contributions to the spread in results.

  9. Atmospheric Turbulence Modeling for Aero Vehicles: Fractional Order Fits

    Science.gov (United States)

    Kopasakis, George

    2015-01-01

    Atmospheric turbulence models are necessary for the design of both inlet/engine and flight controls, as well as for studying coupling between the propulsion and the vehicle structural dynamics for supersonic vehicles. Models based on the Kolmogorov spectrum have been previously utilized to model atmospheric turbulence. In this paper, a more accurate model is developed in its representative fractional order form, typical of atmospheric disturbances. This is accomplished by first scaling the Kolmogorov spectral to convert them into finite energy von Karman forms and then by deriving an explicit fractional circuit-filter type analog for this model. This circuit model is utilized to develop a generalized formulation in frequency domain to approximate the fractional order with the products of first order transfer functions, which enables accurate time domain simulations. The objective of this work is as follows. Given the parameters describing the conditions of atmospheric disturbances, and utilizing the derived formulations, directly compute the transfer function poles and zeros describing these disturbances for acoustic velocity, temperature, pressure, and density. Time domain simulations of representative atmospheric turbulence can then be developed by utilizing these computed transfer functions together with the disturbance frequencies of interest.

  10. Fusing Simulation Results From Multifidelity Aero-servo-elastic Simulators - Application To Extreme Loads On Wind Turbine

    DEFF Research Database (Denmark)

    Abdallah, Imad; Sudret, Bruno; Lataniotis, Christos

    2015-01-01

    bending moment at the blade root of a large wind turbine as a function of wind speed, turbulence and shear exponent in the presence of model uncertainty and non-stationary noise in the output. The extreme responses are obtained by two widely accepted numerical aero-servo-elastic simulators, FAST......Fusing predictions from multiple simulators in the early stages of the conceptual design of a wind turbine results in reduction in model uncertainty and risk mitigation. Aero-servo-elastic is a term that refers to the coupling of wind inflow, aerodynamics, structural dynamics and controls. Fusing...

  11. Aerosciences, Aero-Propulsion and Flight Mechanics Technology Development for NASA's Next Generation Launch Technology Program

    Science.gov (United States)

    Cockrell, Charles E., Jr.

    2003-01-01

    The Next Generation Launch Technology (NGLT) program, Vehicle Systems Research and Technology (VSR&T) project is pursuing technology advancements in aerothermodynamics, aeropropulsion and flight mechanics to enable development of future reusable launch vehicle (RLV) systems. The current design trade space includes rocket-propelled, hypersonic airbreathing and hybrid systems in two-stage and single-stage configurations. Aerothermodynamics technologies include experimental and computational databases to evaluate stage separation of two-stage vehicles as well as computational and trajectory simulation tools for this problem. Additionally, advancements in high-fidelity computational tools and measurement techniques are being pursued along with the study of flow physics phenomena, such as boundary-layer transition. Aero-propulsion technology development includes scramjet flowpath development and integration, with a current emphasis on hypervelocity (Mach 10 and above) operation, as well as the study of aero-propulsive interactions and the impact on overall vehicle performance. Flight mechanics technology development is focused on advanced guidance, navigation and control (GN&C) algorithms and adaptive flight control systems for both rocket-propelled and airbreathing vehicles.

  12. Physics and Measurement of Aero-Optical Effects: Past and Present

    Science.gov (United States)

    Jumper, Eric J.; Gordeyev, Stanislav

    2017-01-01

    The field of aero-optics is devoted to the study of the effects of turbulent flow fields on laser beams projected from airborne laser systems. This article reviews the early and present periods of research in aero-optics. Both periods generated impressive amounts of research activity; however, the types and amount of data differ greatly in accuracy, quality, and type owing to the development of new types of instrumentation available to collect and analyze the aberrated wave fronts of otherwise collimated laser beams projected through turbulent compressible flow fields of the type that form over beam directors. This review traces the activities and developments associated with both periods but particularly focuses on the development of modern high-bandwidth wave-front sensors used in the present research period. We describe how these modern wave-front data are collected and analyzed and the fluid mechanic information that can be gleaned from them; the use of these data in the fundamental study of turbulence is emphasized.

  13. Digital holographic interferometry for characterizing deformable mirrors in aero-optics

    Science.gov (United States)

    Trolinger, James D.; Hess, Cecil F.; Razavi, Payam; Furlong, Cosme

    2016-08-01

    Measuring and understanding the transient behavior of a surface with high spatial and temporal resolution are required in many areas of science. This paper describes the development and application of a high-speed, high-dynamic range, digital holographic interferometer for high-speed surface contouring with fractional wavelength precision and high-spatial resolution. The specific application under investigation here is to characterize deformable mirrors (DM) employed in aero-optics. The developed instrument was shown capable of contouring a deformable mirror with extremely high-resolution at frequencies exceeding 40 kHz. We demonstrated two different procedures for characterizing the mechanical response of a surface to a wide variety of input forces, one that employs a high-speed digital camera and a second that employs a low-speed, low-cost digital camera. The latter is achieved by cycling the DM actuators with a step input, producing a transient that typically lasts up to a millisecond before reaching equilibrium. Recordings are made at increasing times after the DM initiation from zero to equilibrium to analyze the transient. Because the wave functions are stored and reconstructable, they can be compared with each other to produce contours including absolute, difference, and velocity. High-speed digital cameras recorded the wave functions during a single transient at rates exceeding 40 kHz. We concluded that either method is fully capable of characterizing a typical DM to the extent required by aero-optical engineers.

  14. Aero-engine fault diagnosis applying new fast support vector algorithm

    Institute of Scientific and Technical Information of China (English)

    XU Qi-hua; GENG Shuai; SHI Jun

    2012-01-01

    A new fast learning algorithm was presented to solve the large-scale support vector machine ( SVM ) training problem of aero-engine fault diagnosis.The relative boundary vectors ( RBVs ) instead of all the original training samples were used for the training of the binary SVM fault classifiers.This pruning strategy decreased the number of final training sample significantly and can keep classification accuracy almost invariable.Accordingly , the training time was shortened to 1 / 20compared with basic SVM classifier.Meanwhile , owing to the reduction of support vector number , the classification time was also reduced.When sample aliasing existed , the aliasing sample points which were not of the same class were eliminated before the relative boundary vectors were computed.Besides , the samples near the relative boundary vectors were selected for SVM training in order to prevent the loss of some key sample points resulted from aliasing.This can improve classification accuracy effectively.A simulation example to classify 5classes of combination fault of aero-engine gas path components was finished and the total fault classification accuracy reached 96.1%.Simulation results show that this fast learning algorithm is effective , reliable and easy to be implemented for engineering application.

  15. Aero-optic analysis of anisotropic turbulent boundary layer by direct integration

    Science.gov (United States)

    Taylor, S.; Price, J.; Chen, C. P.; Pond, John E.; Sutton, G. W.

    2013-09-01

    Aero-optic aberrations that effect optical sensor performance and laser beam propagation, can be caused by changes in the index-of-refraction field as the optical wave traverses a compressible non-uniform, turbulent flowfield. Mean flowfield non-uniformities cause bore sight error and blurring and, if the mean flowfield is unsteady, jitter. Turbulence causes blurring and high frequency jitter. Blurring also causes the signal-to-noise ratio to decrease and image distortion, and adversely affects centroid location for precision tracking. The objective of this study is to develop an unified approach for whole-field aero-optics prediction using hybrid LES/RANS (Large Eddy Simulation/Reynolds Average Navier-Stokes) turbulence modeling in combination with a newly formulated optical Modulation Transfer Function (MTF). The whole field turbulence includes the near-vehicle boundary layer mean and turbulence, as well as far-field atmospheric turbulence. A flat plate compressible boundary layer case is used to demonstrate the methodology. the abstract two lines below author names and addresses.

  16. Research and Development of Some Advanced High Temperature Titanium Alloys for Aero-engine

    Directory of Open Access Journals (Sweden)

    CAI Jian-ming

    2016-08-01

    Full Text Available Some advanced high temperature titanium alloys are usually selected to be manufactured into blade, disc, case, blisk and bling under high temperature environment in compressor and turbine system of a new generation high thrust-mass ratio aero-engine. The latest research progress of 600℃ high temperature titanium alloy, fireproof titanium alloy, TiAl alloy, continuous SiC fiber reinforced titanium matrix composite and their application technology in recent years in China were reviewed in this paper. The key technologies need to be broken through in design, processing and application of new material and component are put forward, including industrial ingot composition of high purified and homogeneous control technology, preparation technology of the large size bar and special forgings, machining technology of blisk and bling parts, material property evaluation and application design technique. The future with the continuous application of advanced high temperature titanium alloys, will be a strong impetus to the development of China's aero-engine technology.

  17. Implications of the homogeneous turbulence assumption on the aero-optic linking equation

    Science.gov (United States)

    Hugo, Ronald J.; Jumper, Eric J.

    1995-09-01

    This paper investigates the validity of applying the simplified (under the assumptions of isotropic and homogeneous turbulence) aero-optic linking equation to a flowfield that is known to consist of anisotropic and nonhomogeneous turbulence. The investigation is performed in the near nozzle-region of a heated two-dimensional jet, and the study makes use of a conditional sampling experiment to acquire a spatio-temporal temperature field data base for the heated jet flowfield. After compensating for the bandwidth limitations of constant-current-wire temperature measurements, the temperature field data base is applied to the computation of optical degradation through both direct methods and indirect methods relying on the aero-optic linking equation. The simplified version of the linking equation was found to provide very good agreement with direct calculations provided that the length scale of the density fluctuations was interpreted as being the integral scale, with the limits of the integration being the two first zero crossings of the covariance coefficient function.

  18. Applicability of the Aero-Optic Linking Equation to a Highly Coherent, Transitional Shear Layer

    Science.gov (United States)

    Hugo, Ronald J.; Jumper, Eric J.

    2000-08-01

    We investigate the validity of applying a simplified (under the assumptions of isotropic and homogeneous turbulence) aero-optic linking equation to a flow field that is known to consist of anisotropic and nonhomogeneous turbulence. The investigation is performed in the near-nozzle region of a heated two-dimensional jet, and the study makes use of a conditional-sampling experiment to acquire a spatiotemporal temperature field database for the heated-jet flow field. After compensating for the bandwidth limitations of constant-current wire temperature measurements, the temperature field database is applied to the computation of optical degradation through both direct and indirect methods, relying on the aero-optic linking equation. The simplified version of the linking equation was found to provide good agreement with direct calculations, provided that the length scale of the density fluctuations was interpreted as being the integral scale, with the limits of integration being the first two zero crossings of the covariance coefficient function.

  19. A Rapid Method to Achieve Aero-Engine Blade Form Detection

    Directory of Open Access Journals (Sweden)

    Bin Sun

    2015-06-01

    Full Text Available This paper proposes a rapid method to detect aero-engine blade form, according to the characteristics of an aero-engine blade surface. This method first deduces an inclination error model in free-form surface measurements based on the non-contact laser triangulation principle. Then a four-coordinate measuring system was independently developed, a special fixture was designed according to the blade shape features, and a fast measurement of the blade features path was planned. Finally, by using the inclination error model for correction of acquired data, the measurement error that was caused by tilt form is compensated. As a result the measurement accuracy of the Laser Displacement Sensor was less than 10 μm. After the experimental verification, this method makes full use of optical non-contact measurement fast speed, high precision and wide measuring range of features. Using a standard gauge block as a measurement reference, the coordinate system conversion data is simple and practical. It not only improves the measurement accuracy of the blade surface, but also its measurement efficiency. Therefore, this method increases the value of the measurement of complex surfaces.

  20. 小米淀粉热膨化条件的优化%Optimization of thermal expansion parameters of millet starch

    Institute of Scientific and Technical Information of China (English)

    梁万礼; 张建超; 朱丽丹; 马晓军

    2012-01-01

    通过单因素及正交实验以膨化率和脆度为指标确定了小米淀粉热膨化的最佳工艺条件。结果表明,对膨化效果的影响因素次序为水分含量〉膨化温度〉膨化时间,其中水分含量对膨化效果的影响高度显著(P〈0.01)。膨化的最佳条件为水分含量8%,膨化温度310℃,膨化时间50s。此条件下膨化制小米饼的膨化率和脆度分别为8.32及0.254kg·s,脆度优于市售的品牌雪饼(0.424kg·s),感官评价也得到了同样的结论。实验显示以小米为原料制作米雪饼切实可行。%The optimal condition of thermal expansion of millet starch was investigated by orthogonal array design based on single factor experiments using expansion ratio and crispness as indicators.Results showed that the primary and secondary sequence of influence factors were in the following order of moisture content 〉 expansion temperature 〉 expansion time and a significant effect of moisture content was observed ( P 〈 O.Oi ) .The optimal condition of thermal expansion was as follows.moisture content 8%, expansion temperature 310~C and expansion time 50s.A maximum expansion ratio of 8.32 and crispness of 0.254kg ~ s which was better than rice cakes on the market(0.424kg ~ s) were obtained under the optimal values of related parameters. Sensory evaluation also confirmed that the textural quality of sample was nicer than the latter.Experiments revealed that it was feasible to make rice cakes from millet.

  1. Lab determination of soil thermal Conductivity. Fundamentals, geothermal applications and relationship with other soil parameters; Medida de la conductividad termica del suelo en laboratorio. Fundamentos fisicos, aplicaciones geotermicas y relaciones con otros parametros del suelo

    Energy Technology Data Exchange (ETDEWEB)

    Nope Gomez, F. I.; Santiago, C. de

    2014-07-01

    Shallow geothermal energy application in buildings and civil engineering works (tunnels, diaphragm walls, bridge decks, roads, and train/metro stations) are spreading rapidly all around the world. the dual role of these energy geostructures makes their design challenging and more complex with respect to conventional projects. Besides the geotechnical parameters, thermal behavior parameters are needed in the design and dimensioning to warrantee the thermo-mechanical stability of the geothermal structural element. As for obtaining any soil thermal parameter, both in situ and laboratory methods can be used. The present study focuses on a lab test known the need ke method to measure the thermal conductivity of soils (λ). Through this research work, different variables inherent to the test procedure, as well as external factors that may have an impact on thermal conductivity measurements were studied. Samples extracted from the cores obtained from a geothermal drilling conducted on the campus of the Polytechnic University of Valencia, showing different mineralogical and nature composition (granular and clayey) were studied different (moisture and density) compacting conditions. 550 thermal conductivity measurements were performed, from which the influence of factors such as the degree of saturation-moisture, dry density and type of material was verified. Finally, a stratigraphic profile with thermal conductivities ranges of each geologic level was drawn, considering the degree of saturation ranges evaluated in lab tests, in order to be compared and related to thermal response test, currently in progress. Finally, a test protocol is set and proposed, for both remolded and undisturbed samples, under different saturation conditions. Together with this test protocol, a set of recommendations regarding the configuration of the measuring equipment, treatment of samples and other variables, are posed in order to reduce errors in the final results. (Author)

  2. Aero-acoustics in a tangential blower: validation of the CFD flow distribution using advanced PIV techniques

    Directory of Open Access Journals (Sweden)

    Jean-Yves Noël

    2007-12-01

    Full Text Available Noise reduction is of increasing importance in the community. Consequently, the development of aero-acoustics is gaining special focus within industry. Computational Aero-Acoustics (CAA, the coupling of Computational Fluid Dynamics (CFD and Computational Acoustics (CA, is being used in the design and assessment of a range of products from HVAC ducts to domestic appliances. The process for carrying out an Aero-Acoustic simulation begins with the solution of the transient flow dynamics in order to compute accurately the pressure fluctuations at a number of points in the computational domain. These fluctuations are passed to the acoustic code to propagate the acoustic waves through the system and determine its acoustic signature. To minimize errors in the acoustic propagation analysis it is thus essential that accurate predictions of the noise sources be obtained. This paper concentrates on the CFD part of the aero-acoustic simulation. The case considered has been taken from the European project DESTINY:3 and comprises a tangential blower located inside a complex duct system. Air is drawn into the fan through two inlets and exits through a single duct. The computational methodology and flow field predictions are presented and compared to experimental PIV data. The numerical predictions were found to be in good agreement with the experimental data, reproducing the asymmetries in the flow field.

  3. 76 FR 67243 - In the Matter of Accesspoint Corp., Aero Performance Products, Inc., Apex Resources Group, Inc...

    Science.gov (United States)

    2011-10-31

    ... COMMISSION In the Matter of Accesspoint Corp., Aero Performance Products, Inc., Apex Resources Group, Inc., Aradyme Corp., Bancroft Uranium, Inc., Fightersoft Multimedia Corp., Fortress Financial Group, Inc., and... Resources Group, Inc. because it has not filed any periodic reports since the period ended March 31,...

  4. 76 FR 72235 - Abviva, Inc., ACTIS Global Ventures, Inc., aeroTelesis, Inc., Amwest Insurance Group, Inc., and...

    Science.gov (United States)

    2011-11-22

    ... From the Federal Register Online via the Government Publishing Office SECURITIES AND EXCHANGE COMMISSION Abviva, Inc., ACTIS Global Ventures, Inc., aeroTelesis, Inc., Amwest Insurance Group, Inc., and... information concerning the securities of ACTIS Global Ventures, Inc. because it has not filed any...

  5. 75 FR 22512 - Airworthiness Directives; Piaggio Aero Industries S.p.A. Model PIAGGIO P-180 Airplanes

    Science.gov (United States)

    2010-04-29

    ... Industries S.p.A. Model PIAGGIO P-180 Airplanes AGENCY: Federal Aviation Administration (FAA), Department of....regulations.gov ; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through... 2. The FAA amends Sec. 39.13 by adding the following new AD: 2010-09-09 Piaggio Aero Industries...

  6. 76 FR 10224 - Airworthiness Directives; PIAGGIO AERO INDUSTRIES S.p.A Model PIAGGIO P-180 Airplanes

    Science.gov (United States)

    2011-02-24

    ... INDUSTRIES S.p.A Model PIAGGIO P-180 Airplanes AGENCY: Federal Aviation Administration (FAA), Department of... this AD, contact Piaggio Aero Industries S.p.A., Via Cibrario, 4-16154 Genoa, Italy; phone: +39 010... that the towing bar P/N 01-1227-0000 or similar ferromagnetic masses are prohibited to be carried...

  7. 75 FR 63058 - Airworthiness Directives; PIAGGIO AERO INDUSTRIES S.p.A Model PIAGGIO P-180 Airplanes

    Science.gov (United States)

    2010-10-14

    ... INDUSTRIES S.p.A Model PIAGGIO P-180 Airplanes AGENCY: Federal Aviation Administration (FAA), Department of....regulations.gov ; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through... 2. The FAA amends Sec. 39.13 by adding the following new AD: 2010-21-14 PIAGGIO AERO INDUSTRIES...

  8. 76 FR 7694 - Airworthiness Directives; PIAGGIO AERO INDUSTRIES S.p.A Model PIAGGIO P-180 Airplanes

    Science.gov (United States)

    2011-02-11

    ... INDUSTRIES S.p.A Model PIAGGIO P-180 Airplanes AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The..., etc. for PIAGGIO AERO INDUSTRIES S.p.A Model PIAGGIO P-180 airplanes. As published, the...

  9. 75 FR 68172 - Airworthiness Directives; Piaggio Aero Industries S.p.A. Model PIAGGIO P-180 Airplanes

    Science.gov (United States)

    2010-11-05

    ... Industries S.p.A. Model PIAGGIO P-180 Airplanes AGENCY: Federal Aviation Administration (FAA), Department of... identified in this AD, contact Piaggio Aero Industries S.p.a., Via Cibrario, 4-16154 Genoa, Italy; phone: +39... between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the...

  10. 75 FR 67639 - Airworthiness Directives; Piaggio Aero Industries S.p.A Model PIAGGIO P-180 Airplanes

    Science.gov (United States)

    2010-11-03

    ... Industries S.p.A Model PIAGGIO P-180 Airplanes AGENCY: Federal Aviation Administration (FAA), Department of... Airplane Flight Manual, stating that the towing bar P/N 01-1227-0000 or similar ferromagnetic masses are... maintenance requirements and/or airworthiness limitations developed by Piaggio Aero Industries S.p.A....

  11. Laser drilling of thermal barrier coated jet-engine components

    Science.gov (United States)

    Sezer, H. K.

    Aero engine hot end components are often covered with ceramic Thermal Barrier Coatings (TBCs). Laser drilling in the TBC coated components can be a source of service life TBC degradation and spallation. The present study aims to understand the mechanisms of TBC delamination and develop techniques to drill holes without damaging the TBC, Nimonic 263 workpieces coated with TBC are used in the experiments. Microwave non-destructive testing (NDT) is employed to monitor the integrity of the coating /substrate interfaces of the post-laser drilled materials. A numerical modelling technique is used to investigate the role of melt ejection on TBC delamination. The model accounts for the vapour and the assist gas flow effects in the process. Broadly, melt ejection induced mechanical stresses for the TBC coating / bond coating and thermal effects for the bond coating / substrate interfaces are found the key delamination mechanisms. Experiments are carried out to validate the findings from the model. Various techniques that enable laser drilling without damaging the TBC are demonstrated. Twin jet assisted acute angle laser drilling is one successful technique that has been analysed using the melt ejection simulation. Optimisation of the twin jet assisted acute angle laser drilling process parameters is carried out using Design of Experiments (DoE) and statistical modelling approaches. Finally, an industrial case study to develop a high speed, high quality laser drilling system for combustor cans is described. Holes are drilled by percussion and trepan drilling in TBC coated and uncoated Haynes 230 workpieces. The production rate of percussion drilling is significantly higher than the trepan drilling, however metallurgical hole quality and reproducibility is poor. A number of process parameters are investigated to improve these characteristics. Gas type and gas pressure effects on various characteristics of the inclined laser drilled holes are investigated through theoretical

  12. An extensive investigation on nucleation, growth parameters, crystalline perfection, spectroscopy, thermal, optical, microhardness, dielectric and SHG studies on potential NLO crystal - Ammonium Hydrogen L-tartarte

    Science.gov (United States)

    Hanumantharao, Redrothu; Kalainathan, S.; Bhagavannarayana, G.; Madhusoodanan, U.

    2013-02-01

    Ammonium Hydrogen L-tartarte (AMT), an organic nonlinear optical crystal was grown by slow evaporation method at ambient temperature. Solubility, metastable zone width and induction period of Ammonium Hydrogen L-tartarte in aqueous solution were determined. Good quality crystals were selected and characterized by Single crystal XRD, HR-XRD, FT-IR, 1H NMR, Mass, TGA-DTA, SEM, EDAX, optical and NLO studies. Single crystal XRD analysis revealed that the crystal system belongs to orthorhombic with cell parameters a = 7.65 Å, b = 7.85 Å and c = 11.07 Å. High-resolution-X-ray diffraction (HR-XRD) analysis was carried out to study the crystalline perfection of the grown crystal. 1H NMR and FTIR spectrum thus confirmed the presence of functional groups of the grown crystal. Molecular mass of AMT was measured accurately by mass spectroscopic analysis. Surface features of the grown crystal were analyzed by SEM, AFM, chemical etching and the presence of elements in the compound was identified by EDAX analysis. Thermal behavior of the grown crystal has been studied by TG/DTA analysis. The recorded UV-Vis-NIR spectrum shows excellent transmission in the region of 190-1100 nm. The Vickers and Knoop's microhardness studies have been carried out on AMT crystals over a range of 10-50 g. Hardness anisotropy has been observed in accordance with the orientation of the crystal. Fluorescence spectral studies were carried in the range of 280-500 nm for the grown crystal. The SHG conversion efficiency and laser damage threshold were measured using an Nd: YAG laser (1064 nm).

  13. Effects of laser processing parameters on thermal behavior and melting/solidification mechanism during selective laser melting of TiC/Inconel 718 composites

    Science.gov (United States)

    Shi, Qimin; Gu, Dongdong; Xia, Mujian; Cao, Sainan; Rong, Ting

    2016-10-01

    A three-dimensional finite element model is proposed to study the effects of laser power and scan speed on the thermal behavior and melting/solidification mechanism during selective laser melting (SLM) of TiC/Inconel 718 powder system. The cooling time during powder delivery is taken into account to simulate the actual production process well. It shows obviously the existence of heat accumulation effect in SLM process and, the tailored set of cooling time of 10 ms during powder delivery alleviates that effectively. The maximum temperature gradient in the molten pool slightly increases from 1.30×104 °C/mm to 2.60×104 °C/mm as the laser power is increased from 75 W to 150 W. However, it is negligibly sensitive to the variation of scan speed. There is a positive corresponding relationship between the maximum rate of temperature change and processing parameters. A low laser power (75 W) or a high scan speed (300 mm/s) is more energy efficient in Z-direction of the molten pool, giving rise to a deep-narrow cross section of the pool. Whereas, a high laser power (150 W) or a low scan speed (50 mm/s) causes a shallow-wide cross section of the molten pool, meaning it is more energy efficient in the Y-direction of the melt. The combination of a laser power of 125 W and a scan speed of 100 mm/s contributes to achieve a sound metallurgical bonding between the neighbor layers and tracks, due to the proper molten pool size (width: 109.3 μm; length: 120.7 μm; depth: 67.8 μm). The SLM experiments on TiC/Inconel 718 powder system are performed to verify the reliability and accuracy of the physical model and, simulation results are proved to be correct.

  14. Dendritic Growth, Solidification Thermal Parameters, and Mg Content Affecting the Tensile Properties of Al-Mg-1.5 Wt Pct Fe Alloys

    Science.gov (United States)

    Gomes, Leonardo F.; Silva, Bismarck L.; Garcia, Amauri; Spinelli, José E.

    2017-02-01

    Al-Mg-Fe alloys are appointed as favorable ones with respect to the costs and all the required properties for successful vessel service. However, the experimental inter-relations of solidification thermal parameters, microstructure, and mechanical strength are still undetermined. In the present research work, the dependences of tensile properties on the length scale of the dendritic morphology of ternary Al-1.2 wt pct Mg-1.5 wt pct Fe and Al-7 wt pct Mg-1.5 wt pct Fe alloys are examined. Transient heat flow conditions during solidification have been achieved by the use of a directional solidification system, thus permitting a comprehensive characterization of the dendritic microstructures to be performed. Thermo-Calc computations, X-ray diffraction, and scanning electron microscopy analyses are carried out to give support to the extensive microstructural evaluation performed with both ternary Al-Mg-Fe alloys. Experimental growth relations of primary, λ 1, and secondary, λ 2, dendrite arm spacings with cooling rate ( {dot T}_{{L}} ) and of tensile properties with λ 2 are proposed. For both alloys examined, Hall-Petch type formulas show that the tensile strength increases with the decrease in λ 2. The soundest strength-ductility balance is exhibited by the Al-7 wt pct Mg-1.5 wt pct Fe alloy specimen with refined microstructure. This is shown to be due to a more homogeneous distribution of intermetallic particles in connection with solid solution strengthening propitiated by Mg. Functional experimental inter-relations of tensile properties with growth (V L) and cooling rates ( {dot T}_{{L}} ) for both ternary Al-Mg-Fe alloys have also been derived.

  15. Performance Degradation of Thermal Parameters during Cycle Ageing of High Energy Density Ni-Mn-Co based Lithium-Ion Battery Cells

    DEFF Research Database (Denmark)

    Stanciu, Tiberiu; Stroe, Daniel Loan; Swierczynski, Maciej Jozef

    2016-01-01

    The accelerated demand for electrifying the transportation sector, coupled with the continuous improvement of rechargeable batteries’ characteristics, have made modern high-energy Lithium-ion (Li-ion) batteries the standard choice for hybrid and electric vehicles (EVs). Consequently, Li......-ion batteries’ electrochemical and thermal characteristics are very important topics, putting them at the forefront of the research. Along with the electrical performance of Li-ion battery cells, their thermal behavior needs to be accurately predicted during operation and over the lifespan of the application...... as well, since the thermal management of the battery is crucial for the safety of the EV driver. Moreover, the thermal management system can significantly lower the degradation rate of the battery pack and thus reduce costs. In this paper, the thermal characterization of a commercially available Nickel...

  16. The effect of filler parameters on the healing of thermal conductivity and mechanical properties of a thermal interface material based on a self-healable organic-inorganic polymer matrix

    Science.gov (United States)

    Zhong, Nan; Garcia, Santiago J.; van der Zwaag, Sybrand

    2016-08-01

    Thermal interface materials (TIMs) are widely used in all kinds of electronic devices to handle the heat dissipation and the mechanical anchoring of the heat producing component. The aging of TIMs may lead to delamination and internal crack formation causing a loss of heat transfer and mechanical integrity both leading to premature device failure. In the present work, a novel TIM system based on a self-healing organic-inorganic polymer matrix filled with spherical glass beads is presented which is capable of healing both the thermal conductivity and the mechanical properties upon thermal activation. The effect of particle volume concentration (PVC) and particle size on tensile strength and thermal conductivity healing behavior is investigated. The results show that a higher PVC increases the mechanical property but decreases mechanical healing. For the same PVC, bigger particles lead to lower mechanical properties but higher thermal conductivities and higher mechanical healing efficiencies.

  17. An AeroCom assessment of black carbon in Arctic snow and sea ice

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, C.; Flanner, M. G.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Berntsen, T. K.; Bian, H.; Carslaw, K. S.; Chin, M.; De Luca, N.; Diehl, T.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Koch, D.; Liu, X.; Mann, G. W.; Penner, J. E.; Pitari, G.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Steenrod, S. D.; Stier, P.; Takemura, T.; Tsigaridis, K.; van Noije, T.; Yun, Y.; Zhang, K.

    2014-01-01

    Though many global aerosols models prognose surface deposition, only a few models have been used to directly simulate the radiative effect from black carbon (BC) deposition to snow and sea ice. In this paper, we apply aerosol deposition fields from 25 models contributing to two phases of the Aerosol Comparisons between Observations and Models (AeroCom) project to simulate and evaluate within-snow BC concentrations and radiative effect in the Arctic. We accomplish this by driving the offline land and sea ice components of the Community Earth System Model with different deposition fields and meteorological conditions from 2004 to 2009, during which an extensive field campaign of BC measurements in Arctic snow occurred. We find that models generally underestimate BC concentrations in snow in northern Russia and Norway, while overestimating BC amounts elsewhere in the Arctic. Although simulated BC distributions in snow are poorly correlated with measurements, mean values are reasonable. The multi-model mean (range) bias in BC concentrations, sampled over the same grid cells, snow depths, and months of measurements, are -4.4 (-13.2 to +10.7) ng g-1 for an earlier phase of AeroCom models (phase I), and +4.1 (-13.0 to +21.4) ng g-1 for a more recent phase of AeroCom models (phase II), compared to the observational mean of 19.2 ng g-1. Factors determining model BC concentrations in Arctic snow include Arctic BC emissions, transport of extra-Arctic aerosols, precipitation, deposition efficiency of aerosols within the Arctic, and meltwater removal of particles in snow. Sensitivity studies show that the model–measurement evaluation is only weakly affected by meltwater scavenging efficiency because most measurements were conducted in non-melting snow. The Arctic (60–90° N) atmospheric residence time for BC in phase II models ranges from 3.7 to 23.2 days, implying large inter-model variation in local BC deposition efficiency. Combined with

  18. An AeroCom Assessment of Black Carbon in Arctic Snow and Sea Ice

    Science.gov (United States)

    Jiao, C.; Flanner, M. G.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Bernsten, T. K.; Bian, H.; Carslaw, K. S.; Chin, M.; DeLuca, N.; Diehl, T.; Ghan, S. J.; Iversen, T.; Kirkevag, A.; Koch, D.; Liu, X.; Mann, G. W.; Penner, J. E.; Pitari, G.; Schulz, M.; Seland, O; Skeie, R. B.; Steenrod, S. D.; Stier, P.; Tkemura, T.

    2014-01-01

    Though many global aerosols models prognose surface deposition, only a few models have been used to directly simulate the radiative effect from black carbon (BC) deposition to snow and sea ice. Here, we apply aerosol deposition fields from 25 models contributing to two phases of the Aerosol Comparisons between Observations and Models (AeroCom) project to simulate and evaluate within-snow BC concentrations and radiative effect in the Arctic. We accomplish this by driving the offline land and sea ice components of the Community Earth System Model with different deposition fields and meteorological conditions from 2004 to 2009, during which an extensive field campaign of BC measurements in Arctic snow occurred. We find that models generally underestimate BC concentrations in snow in northern Russia and Norway, while overestimating BC amounts elsewhere in the Arctic. Although simulated BC distributions in snow are poorly correlated with measurements, mean values are reasonable. The multi-model mean (range) bias in BC concentrations, sampled over the same grid cells, snow depths, and months of measurements, are -4.4 (-13.2 to +10.7) ng/g for an earlier phase of AeroCom models (phase I), and +4.1 (-13.0 to +21.4) ng/g for a more recent phase of AeroCom models (phase II), compared to the observational mean of 19.2 ng/g. Factors determining model BC concentrations in Arctic snow include Arctic BC emissions, transport of extra-Arctic aerosols, precipitation, deposition efficiency of aerosols within the Arctic, and meltwater removal of particles in snow. Sensitivity studies show that the model-measurement evaluation is only weakly affected by meltwater scavenging efficiency because most measurements were conducted in non-melting snow. The Arctic (60-90degN) atmospheric residence time for BC in phase II models ranges from 3.7 to 23.2 days, implying large inter-model variation in local BC deposition efficiency. Combined with the fact that most Arctic BC deposition originates

  19. An overview of aeroelasticity studies for the National Aero-Space Plane

    Science.gov (United States)

    Ricketts, Rodney H.; Noll, Thomas E.; Whitlow, Woodrow, Jr.; Huttsell, Lawrence J.

    1993-01-01

    The National Aero-Space Plane (NASP), or X-30, is a single-stage-to-orbit vehicle that is designed to takeoff and land on conventional runways. Research in aeroelasticity was conducted by the NASA and the Wright Laboratory to support the design of a flight vehicle by the national contractor team. This research includes the development of new computational codes for predicting unsteady aerodynamic pressures. In addition, studies were conducted to determine the aerodynamic heating effects on vehicle aeroelasticity and to determine the effects of fuselage flexibility on the stability of the control systems. It also includes the testing of scale models to better understand the aeroelastic behavior of the X-30 and to obtain data for code validation and correlation. This paper presents an overview of the aeroelastic research which has been conducted to support the airframe design.

  20. Evaluations on aero-optic effects of subsonic airborne electro-optical system

    Institute of Scientific and Technical Information of China (English)

    Kexin Yin; Huilin Jiang

    2006-01-01

    @@ A simple method based on CFD code and Matlab for aero-optic effects is presented. Density fluctuation from CFD code due to the changes of such factors as altitude, speed, equipment location, and wavelength is introduced as an input to Matlab. The overall calculations are in Matlab. The results show that the performance of electro-optical (EO) system can be improved when the altitude increasing, the speed is as slowly as possible, and the equipment location moves to the leading edge of the airborne platform as far as possible, for the wavelength there is an optimum one when the indexes of contrast and resolution of the system are both considered. All of these methods can minimize the optical aberrations. Several numerical simulations demonstrate the method.

  1. Emergency aero-photo survey after the 5.12 Wenchuan Earthquake, China

    Institute of Scientific and Technical Information of China (English)

    WANG ZhiHua; XU QiDe; XU Bin; ZHANG Wei

    2009-01-01

    After the 5.12 Wenchuan Earthquake which took place on May 12, 2000, aerial remote sensing has rapidly covered all the influence sites of the earthquake, emergency aero-photo interpretation has revealed the disaster distribution limitation, and captured the information of location, dimension of the destroyed houses, roads and other structures, blocked rivers, etc, which provided destroying conditions of the time for rescuing lives, rebuilding traffic lines and estimating disaster situation. The further interpretation and analysis indicate that large scale second growth geological disasters mainly distribute in the distance of 0-300 km and 45°-50° orientation from the epicenter. About 137 latent large-scale landslides and debris-flows will occur in this rain season and coming several years, so how to avoid current geological disasters as well as the latent large disasters should be considered in making rebuilding and developing plan.

  2. Verification of aero-elastic offshore wind turbine design codes under IEA Wind Task XXIII

    DEFF Research Database (Denmark)

    Vorpahl, Fabian; Strobel, Michael; Jonkman, Jason M.

    2014-01-01

    , a tripod and a floating spar buoy—the latest support structure developments in the offshore wind energy industry are covered, and an adaptation of the codes to those developments was initiated. The comparisons, in general, agreed quite well. Differences existed among the predictions were traced back......This work presents the results of a benchmark study on aero-servo-hydro-elastic codes for offshore wind turbine dynamic simulation. The codes verified herein account for the coupled dynamic systems including the wind inflow, aerodynamics, elasticity and controls of the turbine, along...... to differences in the model fidelity, aerodynamic implementation, hydrodynamic load discretization and numerical difficulties within the codes. The comparisons resulted in a more thorough understanding of the modeling techniques and better knowledge of when various approximations are not valid.More importantly...

  3. The neutral atmosphere temperature experiment. [for thermospheric nitrogen measurement on AEROS satellite

    Science.gov (United States)

    Spencer, N. W.; Pelz, D. T.; Niemann, H. B.; Carignan, G. R.; Caldwell, J. R.

    1974-01-01

    The AEROS Neutral Atmosphere Temperature Experiment (NATE) is designed to measure the kinetic temperature of molecular nitrogen in the thermosphere. A quadrupole mass spectrometer tuned to N2 measures the N2 density variation in a small spherical antechamber having a knife-edged orifice which is exposed to the atmosphere at the outer surface of the spacecraft. The changing density of N2 due to the spinning motion of the spacecraft permits determination of the velocity distribution of the N2 from which the temperature is calculated. An alternate mode of operation of the instrument allows measurement of the other gases in the atmosphere as well as N2 permitting determination of the neutral particle composition of the atmosphere.

  4. Unified Multi-speed analysis (UMA) for the condition monitoring of aero-engines

    Science.gov (United States)

    Nembhard, Adrian D.; Sinha, Jyoti K.

    2015-12-01

    For rotating machinery in which speeds and dynamics constantly change, performing vibration-based condition monitoring can be challenging. Thus, an effort is made here to develop a Unified Multi-speed fault diagnosis technique that can exploit useful vibration information available at various speeds from a rotating machine in a single analysis. Commonly applied indicators are computed from data collected from a rig at different speeds for a baseline case and different faults. Four separate analyses are performed: single speed at a single bearing, integrated features from multiple speeds at a single bearing, single speed for integrated features from multiple bearings and the proposed Unified Multi-speed analysis. The Unified Multi-speed approach produces the most conspicuous separation and isolation among the conditions tested. Observations made here suggest integration of more dynamic features available at different speeds improves the learning process of the tool which could prove useful for aero-engine condition monitoring.

  5. Propulsion System Dynamic Modeling of the NASA Supersonic Concept Vehicle for AeroPropulsoServoElasticity

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph W.; Seiel, Jonathan

    2016-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report

  6. Aero-Acoustics of Modern Transonic Fans—Fan Noise Reduction from Its Sources

    Institute of Scientific and Technical Information of China (English)

    L. Xu; J.D. Denton

    2003-01-01

    The noise of aerodynamics nature from modern transonic fan is examined from its sources with the perspective of noise reduction through aero-acoustics design using advanced Computational Fluid Dynamics (CFD) tools.In particular the problems associated with the forward propagating noise in the front is addressed. It is identified that the shock wave spillage from the leading edge near the fan tip is the main source of the tone noise. Two different approaches have been studied to reduce the forward arc tone noise and two state-of-art transonic fans are designed using the strategies developed. The following rig tests show that while the fans exhibit other noise problems,the primary goals of noise reduction have been achieved through both fans and the novel noise reduction concept vindicated.

  7. Emergency aero-photo survey after the 5.12 Wenchuan Earthquake, China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    After the 5.12 Wenchuan Earthquake which took place on May 12, 2008, aerial remote sensing has rapidly covered all the influence sites of the earthquake, emergency aero-photo interpretation has re- vealed the disaster distribution limitation, and captured the information of location, dimension of the destroyed houses, roads and other structures, blocked rivers, etc, which provided destroying condi- tions of the time for rescuing lives, rebuilding traffic lines and estimating disaster situation. The further interpretation and analysis indicate that large scale second growth geological disasters mainly dis- tribute in the distance of 0―300 km and 45°―50° orientation from the epicenter. About 137 latent large-scale landslides and debris-flows will occur in this rain season and coming several years, so how to avoid current geological disasters as well as the latent large disasters should be considered in making rebuilding and developing plan.

  8. Presentations from the Aeroelastic Workshop - latest results from AeroOpt

    Energy Technology Data Exchange (ETDEWEB)

    Hartvig Hansen, M. (ed.)

    2011-10-15

    This report contains the slides of the presentations at the Aeroelastic Workshop held at Risoe-DTU for the wind energy industry in Denmark on October 27, 2011. The scientific part of the agenda at this workshop was 1) Detailed and reduced models of dynamic mooring system (Anders M. Hansen). 2) Bend-twist coupling investigation in HAWC2 (Taeseong Kim). 3) Q3UIC - A new aerodynamic airfoil tool including rotational effects (Nestor R. Garcia). 4) Influence of up-scaling on loads, control and aerodynamic modeling (Helge Aa. Madsen). 5) Aerodynamic damping of lateral tower vibrations (Bjarne S. Kallesoee). 6) Open- and closed-loop aeroservoelastic analysis with HAWCStab2 (Morten H. Hansen). 7) Design and test of a thick, flatback, high-lift multielement airfoil (Frederik Zahle). The presented results are mainly obtained in the EUDP project ''Aeroelastic Optimization of MW Wind Turbines (AeroOpt)''. (Author)

  9. Performance Degradation of Thermal Parameters during Cycle Ageing of High Energy Density Ni-Mn-Co based Lithium-Ion Battery Cells

    DEFF Research Database (Denmark)

    Stanciu, Tiberiu; Stroe, Daniel Loan; Swierczynski, Maciej Jozef

    2016-01-01

    as well, since the thermal management of the battery is crucial for the safety of the EV driver. Moreover, the thermal management system can significantly lower the degradation rate of the battery pack and thus reduce costs. In this paper, the thermal characterization of a commercially available Nickel......-Manganese-Cobalt (NMC) based Li-ion battery cell was performed under different operating conditions: state-of-charge (SOC) levels, charge/discharge current rates and operating temperatures. Moreover, by carrying out accelerated cycle ageing tests on a total of nine NMC-based Li-ion battery cells, the effect of ageing...

  10. Forecasting olive crop yields based on long-term aero biological data series and bio climatic conditions for the southern Iberian Peninsula

    Energy Technology Data Exchange (ETDEWEB)

    Aguilera, F.; Ruiz-Valenzuela, L.

    2014-06-01

    In the present study, bio-meteorological models for predicting olive-crop production in the southern Iberian Peninsula were developed. These covered a 16-year period: 1994-2009. The forecasting models were constructed using the partial least-squares regression method, taking the annual olive yield as the dependent variable, and both aero biological and meteorological parameters as the independent variables. Two regression models were built for the prediction of crop production prior to the final harvest at two different times of the year: July and November. The percentage variance explained by the models was between 83% and 93%. Through these forecasting models, the main factors that influence olive-crop yield were identified. Pollen index and accumulated precipitation, especially as rain recorded during the pre-flowering months, were the most important parameters for providing an explanation of fluctuations in fruit production. The temperature recorded during the two months preceding budburst was another important variable, which showed positive effects on the final yield. The July model that provides accurate predictions of fruit production eight months prior to the final harvest is proposed as an optimal model to forecast fruit produced by olive trees in western Mediterranean areas. (Author)

  11. C-Band Airport Surface Communications System Standards Development. Phase II Final Report. Volume 1: Concepts of Use, Initial System Requirements, Architecture, and AeroMACS Design Considerations

    Science.gov (United States)

    Hall, Edward; Isaacs, James; Henriksen, Steve; Zelkin, Natalie

    2011-01-01

    This report is provided as part of ITT s NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: New ATM Requirements-Future Communications, C-Band and L-Band Communications Standard Development and was based on direction provided by FAA project-level agreements for New ATM Requirements-Future Communications. Task 7 included two subtasks. Subtask 7-1 addressed C-band (5091- to 5150-MHz) airport surface data communications standards development, systems engineering, test bed and prototype development, and tests and demonstrations to establish operational capability for the Aeronautical Mobile Airport Communications System (AeroMACS). Subtask 7-2 focused on systems engineering and development support of the L-band digital aeronautical communications system (L-DACS). Subtask 7-1 consisted of two phases. Phase I included development of AeroMACS concepts of use, requirements, architecture, and initial high-level safety risk assessment. Phase II builds on Phase I results and is presented in two volumes. Volume I (this document) is devoted to concepts of use, system requirements, and architecture, including AeroMACS design considerations. Volume II describes an AeroMACS prototype evaluation and presents final AeroMACS recommendations. This report also describes airport categorization and channelization methodologies. The purposes of the airport categorization task were (1) to facilitate initial AeroMACS architecture designs and enable budgetary projections by creating a set of airport categories based on common airport characteristics and design objectives, and (2) to offer high-level guidance to potential AeroMACS technology and policy development sponsors and service providers. A channelization plan methodology was developed because a common global methodology is needed to assure seamless interoperability among diverse AeroMACS services potentially supplied by multiple service providers.

  12. C-Band Airport Surface Communications System Standards Development. Phase II Final Report. Volume 2: Test Bed Performance Evaluation and Final AeroMACS Recommendations

    Science.gov (United States)

    Hall, Edward; Magner, James

    2011-01-01

    This report is provided as part of ITT s NASA Glenn Research Center Aerospace Communication Systems Technical Support (ACSTS) contract NNC05CA85C, Task 7: New ATM Requirements-Future Communications, C-Band and L-Band Communications Standard Development and was based on direction provided by FAA project-level agreements for New ATM Requirements-Future Communications. Task 7 included two subtasks. Subtask 7-1 addressed C-band (5091- to 5150-MHz) airport surface data communications standards development, systems engineering, test bed and prototype development, and tests and demonstrations to establish operational capability for the Aeronautical Mobile Airport Communications System (AeroMACS). Subtask 7-2 focused on systems engineering and development support of the L-band digital aeronautical communications system (L-DACS). Subtask 7-1 consisted of two phases. Phase I included development of AeroMACS concepts of use, requirements, architecture, and initial high-level safety risk assessment. Phase II builds on Phase I results and is presented in two volumes. Volume I is devoted to concepts of use, system requirements, and architecture, including AeroMACS design considerations. Volume II (this document) describes an AeroMACS prototype evaluation and presents final AeroMACS recommendations. This report also describes airport categorization and channelization methodologies. The purposes of the airport categorization task were (1) to facilitate initial AeroMACS architecture designs and enable budgetary projections by creating a set of airport categories based on common airport characteristics and design objectives, and (2) to offer high-level guidance to potential AeroMACS technology and policy development sponsors and service providers. A channelization plan methodology was developed because a common global methodology is needed to assure seamless interoperability among diverse AeroMACS services potentially supplied by multiple service providers.

  13. Thermal modeling environment for TMT

    Science.gov (United States)

    Vogiatzis, Konstantinos

    2010-07-01

    In a previous study we had presented a summary of the TMT Aero-Thermal modeling effort to support thermal seeing and dynamic loading estimates. In this paper a summary of the current status of Computational Fluid Dynamics (CFD) simulations for TMT is presented, with the focus shifted in particular towards the synergy between CFD and the TMT Finite Element Analysis (FEA) structural and optical models, so that the thermal and consequent optical deformations of the telescope can be calculated. To minimize thermal deformations and mirror seeing the TMT enclosure will be air conditioned during day-time to the expected night-time ambient temperature. Transient simulations with closed shutter were performed to investigate the optimum cooling configuration and power requirements for the standard telescope parking position. A complete model of the observatory on Mauna Kea was used to calculate night-time air temperature inside the enclosure (along with velocity and pressure) for a matrix of given telescope orientations and enclosure configurations. Generated records of temperature variations inside the air volume of the optical paths are also fed into the TMT thermal seeing model. The temperature and heat transfer coefficient outputs from both models are used as input surface boundary conditions in the telescope structure and optics FEA models. The results are parameterized so that sequential records several days long can be generated and used by the FEA model to estimate the observing spatial and temporal temperature range of the structure and optics.

  14. Simulation and Interpretation of the BIBI Ratio CB (.), as a Function of Thermal Parameters of the Low Inertia Polyethylene Wall of Greenhouses

    Science.gov (United States)

    Bendimerad, S.; Mahdjoub, T.; Bibi-Triki, N.; Bessenouci, M. Z.; Draoui, B.; Bechar, H.

    The conventional agricultural tunnel greenhouse is highly widespread in Mediterranean countries, despite the shortcomings it presents, specifically the overheating during the day and the intense cooling at night. This can sometimes lead to an internal thermal inversion. The chapel-shaped glass greenhouse is relatively more efficient, but its evolution remains slow because of its investment cost and amortization. The thermal behavior of a greenhouse has often been studied, mainly during the night. In order to contribute to a better climatic management of the greenhouse, we proposed to develop a thermal analysis model. In this work, a ratio called BIBI was developed to characterize the covering material. This thermal evolution state depends on the degree of air-tightness of this covering material and its physical characteristics. It has to be transparent to solar rays, and must as well absorb and reflect infrared rays emitted by the soil. This leads to trapped solar rays, called the "greenhouse effect". In this paper we propose the modeling and analysis of the thermal behavior of the polyethylene (PE) wall of the experimental tunnel greenhouse.

  15. Two cold-sensitive neurons within one sensillum code for different parameters of the thermal environment in the ant Camponotus rufipes.

    Science.gov (United States)

    Nagel, Manuel; Kleineidam, Christoph J

    2015-01-01

    Ants show high sensitivity when responding to minute temperature changes and are able to track preferred temperatures with amazing precision. As social insects, they have to detect and cope with thermal fluctuations not only for their individual benefit but also for the developmental benefit of the colony and its brood. In this study we investigate the sensory basis for the fine-tuned, temperature guided behaviors found in ants, specifically what information about their thermal environment they can assess. We describe the dose-response curves of two cold-sensitive neurons, associated with the sensillum coelocapitulum on the antenna of the carpenter ant Camponotus rufipes.One cold-sensitive neuron codes for temperature changes, thus functioning as a thermal flux-detector. Neurons of such type continuously provide the ant with information about temperature transients (TT-neuron). The TT-neurons are able to resolve a relative change of 37% in stimulus intensity (ΔT) and antennal scanning of the thermal environment may aid the ant's ability to use temperature differences for orientation.The second cold-sensitive neuron in the S. coelocapitulum responds to temperature only within a narrow temperature range. A temperature difference of 1.6°C can be resolved by this neuron type. Since the working range matches the preferred temperature range for brood care of Camponotus rufipes, we hypothesize that this temperature sensor can function as a thermal switch to trigger brood care behavior, based on absolute (steady state) temperature.

  16. CONSIDERATIONS ON ANATOMY AND PHYSIOLOGY OF LYMPH VESSELS OF UPPER AERO DIGESTIVE ORGANS AND CERVICAL SATELLITE LYMPH NODE GROUP.

    Science.gov (United States)

    Ciupilan, Corina; Stan, C I

    2016-01-01

    The almost constant local regional development of the cancers of upper aero digestive organs requires the same special attention to cervical lymph node metastases, as well as to the primary neoplastic burning point. The surgical therapy alone or associated has a mutilating, damaging character, resulting in loss of an organ and function, most of the times with social implications, involving physical distortions with aesthetic consequences, which make the reintegration of the individual into society questionable. The problem of cervical lymph node metastases is vast and complex, reason why we approached several anatomical and physiological aspects of lymph vessels of the aero digestive organs. Among the available elements during treatment, the headquarters of the tumour, its histologic degree, and its infiltrative nature, each of them significantly influences the possibility of developing metastases.

  17. Electrothermal impedance spectroscopy as a cost efficient method for determining thermal parameters of lithium ion batteries: Prospects, measurement methods and the state of knowledge

    DEFF Research Database (Denmark)

    Swierczynski, Maciej Jozef; Stroe, Daniel Loan; Stanciu, Tiberiu;

    2016-01-01

    for parametrization. Recent research initiated by Barsoukov et al. proposed electrothermal impedance spectroscopy as a novel and non-destructive method of characterizing the thermal properties of batteries by defining frequency dependent thermal impedance. Despite its usefulness, the electrothermal impedance...... spectroscopy method can be still improved in terms of e.g. accuracy and measurement time and it has a potential to be extended to new applications. Performed review indicates that the electrothermal impedance spectroscopy is a very promising, non-destructive, simple and especially cost-efficient method...... for thermal characterization of batteries. The scientific intention of this paper is to collect and systematize the state of knowledge about electrothermal impedance spectroscopy and present different measurement methods on the example of a high-power lithium battery cell and finally to discuss the prospect....

  18. Some Issues Relating to Design and Development of an All-Composite Aero Gas Turbine Engine Rotor

    Directory of Open Access Journals (Sweden)

    K. Gupta

    1998-01-01

    Full Text Available The paper addresses some of the issues involved in the development of an all-composite aero gasturbine engine rotor with a view to reducing the total engine weight and increasing the thrust-weightratio beyond 20: I. It identifies the materials to be used for different components, i.e. shafts, discs andblades in the high and iow temperature regions. The various problems anticipated in its developmentare discussed and solutions recommended, wherever possible.

  19. Fusing Simulation Results From Multifidelity Aero-servo-elastic Simulators - Application To Extreme Loads On Wind Turbine

    DEFF Research Database (Denmark)

    Abdallah, Imad; Sudret, Bruno; Lataniotis, Christos

    2015-01-01

    bending moment at the blade root of a large wind turbine as a function of wind speed, turbulence and shear exponent in the presence of model uncertainty and non-stationary noise in the output. The extreme responses are obtained by two widely accepted numerical aero-servo-elastic simulators, FAST...... and BLADED. With limited high-fidelity response samples, the co-Kriging model produced notably accurate prediction of validation data....

  20. Cost effective aero-photogrammetry toys at active volcanoes: On the use of drones, balloons and kites

    Science.gov (United States)

    Walter, Thomas R.

    2014-05-01

    The availability of aerial photographs allows spatial mapping of flows and fractures, generation of digital elevation models and other change detection. Therefore aerial photographs significantly improve our understanding of volcanic processes. The common problem is the lack of available data for most volcanoes, and the lack of systematic and chronologic repeat surveys. This work summarizes the current state of knowledge and technical implementations that currently revolutionize the field of aero-photogrammetry. By the use of unmanned vehicles, such as octocopters, helicopters and small airplanes, photo data can be acquired from almost any place at distances up to kilometres from the operator. Moreover, by the use of helium balloons, kites or their hybrid helikites, near field aero-photographs are obtained. In combination with modern stitching procedures and computer vision algorithms, the positioning of the camera and the digital elevation model of the ground can be extracted, and the active volcano and its eruption cloud be imaged from almost any perspective. This field is increasingly gaining flexibility, as lightweight cameras are available from visible, infrared and other spectral bands. Here example data are provided from volcanoes that are difficult to access by regular airplanes, showing the strengths and the limits of these new aero-photogrammetry toys.

  1. Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice: Part II: Impact on specific chemical and biochemical quality parameters

    NARCIS (Netherlands)

    Vervoort, L.; Plancken, van der I.; Grauwet, T.; Timmermans, R.A.H.; Mastwijk, H.C.; Matser, A.M.; Hendrickx, M.E.; Loey, van A.

    2011-01-01

    The impact of thermal, high pressure (HP) and pulsed electric field (PEF) processing for mild pasteurization of orange juice was compared on a fair basis, using processing conditions leading to an equivalent degree of microbial inactivation. Examining the effect on specific chemical and biochemical

  2. Adaptive-optic approach to mitigating aero-optic disturbances for a forced shear layer

    Science.gov (United States)

    Nightingale, Alice M.

    Non-uniform, variable-density fields, resulting from compressibility effects in turbulent flows, are the source of aero-optical distortions which cause significant reductions in optical system performance. As a laser beam transverses through an optically active medium, containing index-of-refraction variations, several optical phenomena occur including beam wander, image distortion, and beam defocus. When encountering a variation in the index field, light waves refract causing an otherwise planar wavefront of a laser beam to become aberrated, contributing to the adverse effects mentioned above. Adaptive-Optics (AO) is a technique used to correct for such spatially and temporally varying aberrations on an optical beam by applying a conjugate waveform correction prior to the beams transmission through the flow. Conventional AO systems are bandwidth limited by real-time processing issues and wavefront sensor limitations. Therefore, an alternative to the conventional AO approach has been proposed, developed and evaluated with the goal of overcoming such bandwidth limitations. The alternative AO system, presented throughout this document, consists of two main features; feed-forward flow control and a phase-locked-loop AO control strategy. Initially irregular, unpredictable large-scale structures within a shear layer are regularized using flow control. Subsequently, the resulting optical wavefront, and corresponding optical signal, emerging from the regularized flow becomes more periodic and predictable effectively reducing the bandwidth necessary to make real-time corrections. A phase-lock-loop controller is then used to perform real-time corrections. Wavefront corrections are estimated based upon the regularized flow, while two small aperture laser beams provide a non-intrusive means of acquiring amplitude and phase error measurements. The phase-lock-loop controller uses these signals as feedback to synchronize the deformable mirror's waveform to that of the shear

  3. INFLUENCE OF MAGNETIC AND ELECTRIC GRINDING PARAMETERS ON HARDNESS, WEAR-RESISTANCE AND CHEMICAL COMPOSITION OF PROTECTIVE GAS AND THERMAL COATINGS

    OpenAIRE

    N. V. Spiridonov; M. V. Neroda; I. O. Sokorov

    2010-01-01

    The paper investigates influence of magnetic and electric grinding parameters on formation of physical and mechanical properties of protective coatings. It has been established that it is possible to control chemical composition, properties and qualitative characteristics of hardening coatings while changing technological process parameters

  4. INFLUENCE OF MAGNETIC AND ELECTRIC GRINDING PARAMETERS ON HARDNESS, WEAR-RESISTANCE AND CHEMICAL COMPOSITION OF PROTECTIVE GAS AND THERMAL COATINGS

    Directory of Open Access Journals (Sweden)

    N. V. Spiridonov

    2010-01-01

    Full Text Available The paper investigates influence of magnetic and electric grinding parameters on formation of physical and mechanical properties of protective coatings. It has been established that it is possible to control chemical composition, properties and qualitative characteristics of hardening coatings while changing technological process parameters

  5. Effect of thermal stress on physiological parameters, feed intake and plasma thyroid hormones concentration in Alentejana, Mertolenga, Frisian and Limousine cattle breeds

    Science.gov (United States)

    Pereira, Alfredo M. F.; Baccari, Flávio; Titto, Evaldo A. L.; Almeida, J. A. Afonso

    2008-01-01

    The aim of the present study was to assess the heat tolerance of animals of two Portuguese (Alentejana and Mertolenga) and two exotic (Frisian and Limousine) cattle breeds, through the monitoring of physiological acclimatization reactions in different thermal situations characterized by alternate periods of thermoneutrality and heat stress simulated in climatic chambers. In the experiment, six heifers of the Alentejana, Frisian and Mertolenga breeds and four heifers of the Limousine breed were used. The increase in chamber temperatures had different consequences on the animals of each breed. When submitted to heat stress, the Frisian animals developed high thermal polypnea (more than 105 breath movements per minute), which did not prevent an increase in the rectal temperature (from 38.7°C to 40.0°C). However, only a slight depression in food intake and in blood thyroid hormone concentrations was observed under thermal stressful conditions. Under the thermal stressful conditions, Limousine animals decreased food intake by 11.4% and blood triiodothyronine (T3) hormone concentration decreased to 76% of the level observed in thermoneutral conditions. Alentejana animals had similar reactions. The Mertolenga cattle exhibited the highest capacity for maintaining homeothermy: under heat stressful conditions, the mean thermal polypnea increased twofold, but mean rectal temperature did not increase. Mean food intake decreased by only 2% and mean T3 blood concentration was lowered to 85,6% of the concentration observed under thermoneutral conditions. These results lead to the conclusion that the Frisian animals had more difficulty in tolerating high temperatures, the Limousine and Alentejana ones had an intermediate difficulty, and the Mertolenga animals were by far the most heat tolerant.

  6. Two cold-sensitive neurons within one sensillum code for different parameters of the thermal environment in the ant Camponotus rufipes

    Directory of Open Access Journals (Sweden)

    Manuel eNagel

    2015-09-01

    Full Text Available Ants show high sensitivity when responding to minute temperature changes and are able to track preferred temperatures with amazing precision. As social insects, they have to detect and cope with thermal fluctuations not only for their individual benefit but also for the developmental benefit of the colony and its brood. In this study we investigate the sensory basis for the fine-tuned, temperature guided behaviors found in ants, specifically what information about their thermal environment they can assess. We describe the dose-response curves of two cold-sensitive neurons, associated with the sensillum coelocapitulum on the antenna of the carpenter ant Camponotus rufipes.One cold-sensitive neuron codes for temperature changes, thus functioning as a thermal flux-detector. Neurons of such type continuously provide the ant with information about temperature transients (TT-neuron. The TT-neurons are able to resolve a relative change of 37% in stimulus intensity (ΔT and antennal scanning of the thermal environment may aid the ant’s ability to use temperature differences for orientation.The second cold-sensitive neuron in the S. coelocapitulum responds to temperature only within a narrow temperature range. A temperature difference of 1.6°C can be resolved by this neuron type. Since the working range matches the preferred temperature range for brood care of Camponotus rufipes, we hypothesize that this temperature sensor can function as a thermal switch to trigger brood care behavior, based on absolute (steady state temperature.

  7. Thermal-structural test facilities at NASA Dryden

    Science.gov (United States)

    Deangelis, V. Michael; Anderson, Karl F.

    1992-01-01

    The National Aero-Space Plane (NASP) has renewed interest in hypersonic flight and hot-structures technology development for both the airframe and engine. The NASA Dryden Thermostructures Research Facility is a unique national facility that was designed to conduct thermal-mechanical tests on aircraft and aircraft components by simulating the flight thermal environment in the laboratory. The layout of the facility is presented, which includes descriptions of the high-bay test area, the instrumentation laboratories, the mechanical loading systems, and the state-of-the-art closed-loop thermal control system. The hot-structures test capability of the facility is emphasized by the Mach-3 thermal simulation conducted on the YF-12 airplane. The Liquid-Hydrogen Structural Test Facility, which is presently in the design phase, will provide the capability of thermally testing structures containing hydrogen.

  8. Rotary-Wing Relevant Compressor Aero Research and Technology Development Activities at Glenn Research Center

    Science.gov (United States)

    Welch, Gerard E.; Hathaway, Michael D.; Skoch, Gary J.; Snyder, Christopher A.

    2012-01-01

    Technical challenges of compressors for future rotorcraft engines are driven by engine-level and component-level requirements. Cycle analyses are used to highlight the engine-level challenges for 3000, 7500, and 12000 SHP-class engines, which include retention of performance and stability margin at low corrected flows, and matching compressor type, axial-flow or centrifugal, to the low corrected flows and high temperatures in the aft stages. At the component level: power-to-weight and efficiency requirements impel designs with lower inherent aerodynamic stability margin; and, optimum engine overall pressure ratios lead to small blade heights and the associated challenges of scale, particularly increased clearance-to-span ratios. The technical challenges associated with the aerodynamics of low corrected flows and stability management impel the compressor aero research and development efforts reviewed herein. These activities include development of simple models for clearance sensitivities to improve cycle calculations, full-annulus, unsteady Navier-Stokes simulations used to elucidate stall, its inception, and the physics of stall control by discrete tip-injection, development of an actuator-duct-based model for rapid simulation of nonaxisymmetric flow fields (e.g., due inlet circumferential distortion), advanced centrifugal compressor stage development and experimentation, and application of stall control in a T700 engine.

  9. 3 D FEM analysis of welding residual stress and deformation of aero-engine blisk

    Institute of Scientific and Technical Information of China (English)

    杨建国; 周号; 雷靖; 方洪渊; 张学秋; 曲伸

    2014-01-01

    Aero-engine blisk welded by electron beam welding(EBW)method is a complicated structure.Fixtures were used to control the deformation ofblisk during its manufacturing process.Finite element method was utilized to study the evolution of the welding residual stress and deformation of this structure.In which an attenuation function was applied to the double ellipsoid heat source model based on the characteristic ofEBW,and the effects offixtures on the welding residual stresses and deforamtion were also reserached.The simulation results showed that the temperature contour ofweld cross section vertical to the weld centerline followed a “V”shape.Moreover,large welding residual stress and distortion were found in the interface between blisk and fixtures.The stress concentration was reduced sufficiently in starting and end part ofweldment as the fixtures were removed after welding process,while the removing operation had almost no effects on the welding residual stress in the middle section ofweld bead.

  10. Active generalized predictive control of turbine tip clearance for aero-engines

    Institute of Scientific and Technical Information of China (English)

    Peng Kai; Fan Ding; Yang Fan; Fu Qiang; Li Yong

    2013-01-01

    Active control of turbine blade tip clearance continues to be a concern in design and con-trol of gas turbines. Ever increasing demands for improved efficiency and higher operating temper-atures require more stringent tolerances on turbine tip clearance. In this paper, a turbine tip clearance control apparatus and a model of turbine tip clearance are proposed;an implicit active generalized predictive control (GPC), with auto-regressive (AR) error modification and fuzzy adjustment on control horizon, is presented, as well as a quantitative analysis method of robust per-turbation radius of the system. The active clearance control (ACC) of aero-engine turbine tip clear-ance is evaluated in a lapse-rate take-off transient, along with the comparative and quantitative analysis of the stability and robustness of the active tip clearance control system. The results show that the resultant active tip clearance control system with the improved GPC has favorable steady-state and dynamic performance and benefits of increased efficiency, reduced specific fuel consump-tion, and additional service life.

  11. An Aerodynamic Analysis of a Robustly Redesigned Modern Aero-Engine Fan

    CERN Document Server

    Seshadri, Pranay; Shahpar, Shahrokh

    2016-01-01

    This paper documents results from a recent computational study aimed at de-sensitizing fan stage aerodynamics---in a modern, high bypass ratio aero-engine---to the effects of rear-seal leakage flows. These flows are the result of seal erosion between a rotor and stator disk in an engine, and deterioration over the life of an engine. The density-matching technique for optimization under uncertainty was applied to this problem. This involved RANS and adjoint flow solves of a full fan stage carried out at two different leakage conditions. Here a detailed analysis of the fan stage aerodynamics is carried out to determine why exactly the new design is more insensitive to the effects of leakage flows. Specifically, it is shown that this insensitivity is attributed to three main factors: a slight rearward shift in loading, and thus a reduction in incidence; a reduction in the cross-passage pressure gradient; and a re-acceleration of the flow towards the trailing edge, which prevented any corner separation.

  12. New design of a compact aero-robotic drilling end effector: An experimental analysis

    Directory of Open Access Journals (Sweden)

    Shi Zhenyun

    2016-08-01

    Full Text Available This paper presents the development of a normal adjustment cell (NAC in aero-robotic drilling to improve the quality of vertical drilling, by using an intelligent double-eccentric disk normal adjustment mechanism (2-EDNA, a spherical plain bearing and a floating compress module with sensors. After the surface normal vector is calculated based on the laser sensors’ feedback, the 2-EDNA concept is conceived specifically to address the deviation of the spindle from the surface normal at the drilling point. Following the angle calculation, depending on the actual initial position, two precise eccentric disks (PEDs with an identical eccentric radius are used to rotate with the appropriate angles using two high-resolution DC servomotors. The two PEDs will carry the spindle to coincide with the surface normal, keeping the vertex of the drill bit still to avoid repeated adjustment and position compensation. A series of experiments was conducted on an aeronautical drilling robot platform with a precise NAC. The effect of normal adjustment on bore diameter, drilling force, burr size, drilling heat, and tool wear was analyzed. The results validate that using the NAC in robotic drilling results in greatly improved vertical drilling quality and is attainable in terms of intelligence and accuracy.

  13. New design of a compact aero-robotic drilling end effector:An experimental analysis

    Institute of Scientific and Technical Information of China (English)

    Shi Zhenyun; Yuan Peijiang; Wang Qishen; Chen Dongdong; Wang Tianmiao

    2016-01-01

    This paper presents the development of a normal adjustment cell (NAC) in aero-robotic drilling to improve the quality of vertical drilling, by using an intelligent double-eccentric disk nor-mal adjustment mechanism (2-EDNA), a spherical plain bearing and a floating compress module with sensors. After the surface normal vector is calculated based on the laser sensors’ feedback, the 2-EDNA concept is conceived specifically to address the deviation of the spindle from the sur-face normal at the drilling point. Following the angle calculation, depending on the actual initial position, two precise eccentric disks (PEDs) with an identical eccentric radius are used to rotate with the appropriate angles using two high-resolution DC servomotors. The two PEDs will carry the spindle to coincide with the surface normal, keeping the vertex of the drill bit still to avoid repeated adjustment and position compensation. A series of experiments was conducted on an aeronautical drilling robot platform with a precise NAC. The effect of normal adjustment on bore diameter, dril-ling force, burr size, drilling heat, and tool wear was analyzed. The results validate that using the NAC in robotic drilling results in greatly improved vertical drilling quality and is attainable in terms of intelligence and accuracy.

  14. Propulsion System Dynamic Modeling for the NASA Supersonic Concept Vehicle: AeroPropulsoServoElasticity

    Science.gov (United States)

    Kopasakis, George; Connolly, Joseph; Seidel, Jonathan

    2014-01-01

    A summary of the propulsion system modeling under NASA's High Speed Project (HSP) AeroPropulsoServoElasticity (APSE) task is provided with a focus on the propulsion system for the low-boom supersonic configuration developed by Lockheed Martin and referred to as the N+2 configuration. This summary includes details on the effort to date to develop computational models for the various propulsion system components. The objective of this paper is to summarize the model development effort in this task, while providing more detail in the modeling areas that have not been previously published. The purpose of the propulsion system modeling and the overall APSE effort is to develop an integrated dynamic vehicle model to conduct appropriate unsteady analysis of supersonic vehicle performance. This integrated APSE system model concept includes the propulsion system model, and the vehicle structural-aerodynamics model. The development to date of such a preliminary integrated model will also be summarized in this report.propulsion system dynamics, the structural dynamics, and aerodynamics.

  15. Aero-hydro-elastic simulation platform for wave energy systems and floating wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Kallesoee, B.S.

    2011-01-15

    This report present results from the PSO project 2008-1-10092 entitled Aero-Hydro-Elastic Simulation Platform for Wave Energy Systems and floating Wind Turbines that deals with measurements, modelling and simulations of the world's first combined wave and wind energy platform. The floating energy conversion platform, Poseidon, is owned and operated by Floating Power Plant A/S. The platform has been operating for two test periods; one period where it was operating as a wave energy conversion platform only and one period where the three turbines was mounted and the platform operated as a combined wind and wave energy platform. The PSO project has equipped the platform with comprehensive measurements equipment for measuring platform motion, wave and wind conditions and turbine loads. Data from the first test period has been used for determine if the turbine could be mounted on the platform. Preliminary analysis of data from the second test period indicates that the platform is suitable as wind turbine foundation and that the turbines reduce the platform motion. (Author)

  16. Towards an Aero-Propulso-Servo-Elasticity Analysis of a Commercial Supersonic Transport

    Science.gov (United States)

    Connolly, Joseph W.; Kopasakis, George; Chwalowski, Pawel; Sanetrik, Mark D.; Carlson, Jan-Renee; Silva, Walt A.; McNamara, Jack

    2016-01-01

    This paper covers the development of an aero-propulso-servo-elastic (APSE) model using computational fluid dynamics (CFD) and linear structural deformations. The APSE model provides the integration of the following two previously developed nonlinear dynamic simulations: a variable cycle turbofan engine and an elastic supersonic commercial transport vehicle. The primary focus of this study is to provide a means to include relevant dynamics of a turbomachinery propulsion system into the aeroelastic studies conducted during a vehicle design, which have historically neglected propulsion effects. A high fidelity CFD tool is used here for the integration platform. The elastic vehicle neglecting the propulsion system serves as a comparison of traditional approaches to the APSE results. An overview of the methodology is presented for integrating the propulsion system and elastic vehicle. Static aeroelastic analysis comparisons between the traditional and developed APSE models for a wing tip detection indicate that the propulsion system impact on the vehicle elastic response could increase the detection by approximately ten percent.

  17. Critical parameters for electron beam curing of cationic epoxies and property comparison of electron beam cured cationic epoxies versus thermal cured resins and composites

    Energy Technology Data Exchange (ETDEWEB)

    Janke, C.J.; Norris, R.E.; Yarborough, K. [Oak Ridge National Lab., TN (United States). Oak Ridge Centers for Manufacturing Technology; Havens, S.J. [Oak Ridge Inst. for Science and Education, TN (United States); Lopata, V.J. [Atomic Energy of Canada Ltd., Pinawa, Manitoba (Canada). Whiteshell Labs.

    1997-01-16

    Electron beam curing of composites is a nonthermal, nonautoclave curing process offering the following advantages compared to conventional thermal curing: substantially reduced manufacturing costs and curing times; improvements in part quality and performance; reduced environmental and health concerns; and improvements in material handling. In 1994 a Cooperative Research and Development Agreement (CRADA), sponsored by the Department of Energy Defense Programs and 10 industrial partners, was established to advance electron beam curing of composites. The CRADA has successfully developed hundreds of new toughened and untoughened resins, offering unlimited formulation and processing flexibility. Several patent applications have been filed for this work. Composites made from these easily processable, low shrinkage material match the performance of thermal cured composites and exhibit: low void contents comparable to autoclave cured composites (less than 1%); superb low water absorption values in the same range as cyanate esters (less than 1%); glass transition temperatures rivaling those of polyimides (greater than 390 C); mechanical properties comparable to high performance, autoclave cured composites; and excellent property retention after cryogenic and thermal cycling. These materials have been used to manufacture many composite parts using various fabrication processes including hand lay-up, tow placement, filament winding, resin transfer molding and vacuum assisted resin transfer molding.

  18. Demonstration of thermal control, microstructure control, defect mitigation and process parameter database generation for Ti-6Al-4V Direct Digital Manufacturing - Understanding defect mitigation and process parameter database generation for direct digital manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Dehoff, Ryan R [ORNL; Niyanth S, Niyanth [ORNL; Dinwiddie, Ralph Barton [ORNL; Robson, Alan [University of Tennessee (UT); Jordan, Brian H [ORNL; Chaudhary, Anil [Applied Optimization; Babu, Prof. Sudarsanam Suresh [University of Tennessee, Knoxville (UTK)

    2015-09-01

    Researchers from Manufacturing Demonstration Facility (MDF) at Oak Ridge National Laboratory (ORNL) worked with Applied Optimization (AO) to understand and evaluate the propensity for defect formation in builds manufactured using DM3D-POM laser direct metal deposition. The main aim of this collaboration was to understand the character of powder jet behavior as a function of the nozzle parameters such as cover gas, carrier gas, and shaping gas. In order to evaluate the sensitivities of the parameters used in model, various experiments were performed with in-situ monitoring of the powder stream characteristics using a high speed camera. A wide variety of conditions while keeping the hopper motor rpm constant, including laser power and travel speed were explored. The cross sections of the deposits were characterized using optical microscopy.

  19. Design of wearable data acquisition module for thermal comfort evaluation based on physiological parameters%生理参数热舒适评价中的穿戴式数据采集模块设计

    Institute of Scientific and Technical Information of China (English)

    江朝晖; 王春生; 张静

    2013-01-01

    基于生理参数的热舒适评价是热环境质量评估的新方法.为了提高该方法的实用性,设计了一种穿戴式、多生理参数采集模块.以Zig Bee技术为核心,采用聚偏氟乙烯(PVDF)薄膜传感器、半导体温度传感器和Ω/V变换原理分别检测脉搏、皮肤温度和皮肤电阻.实验结果表明:模块可靠采集腕部的皮肤温度和皮肤电阻,并从脉搏信号获取心搏间期序列,数据发送正常.该模块适合在自然状态下采集生理信号,有利于研究和应用多种生理参数综合评价热舒适性.%Thermal comfort evaluation based on physiological parameters is a new method for thermal environment quality assessment. In order to improve practicability of this method, a kind of wearable acquisition module of multi-physiological parameters is designed. Data acquisition and communication is based on Zig Bee technology, PVDF sensor, semiconductor temperature sensor and principle of Ω/V transform are adopted to respectively measure pulse,skin temperature and skin resistance. The experimental results show that skin temperature and skin resistance on wrist are measured reliably by module, RRI sequences are also extracted from the pulse signal, and data transmission is normal. This module collects physiological signals conveniently in the natural state of user is advantageous to the research and application of comprehensive evaluation for thermal comfort based on multiple physiological parameters

  20. Bimodal Nuclear Thermal Rocket Sizing and Trade Matrix for Lunar, Near Earth Asteroid and Mars Missions

    Science.gov (United States)

    McCurdy, David R.; Krivanek, Thomas M.; Roche, Joseph M.; Zinolabedini, Reza

    2006-01-01

    The concept of a human rated transport vehicle for various near earth missions is evaluated using a liquid hydrogen fueled Bimodal Nuclear Thermal Propulsion (BNTP) approach. In an effort to determine the preliminary sizing and optimal propulsion system configuration, as well as the key operating design points, an initial investigation into the main system level parameters was conducted. This assessment considered not only the performance variables but also the more subjective reliability, operability, and maintainability attributes. The SIZER preliminary sizing tool was used to facilitate rapid modeling of the trade studies, which included tank materials, propulsive versus an aero-capture trajectory, use of artificial gravity, reactor chamber operating pressure and temperature, fuel element scaling, engine thrust rating, engine thrust augmentation by adding oxygen to the flow in the nozzle for supersonic combustion, and the baseline turbopump configuration to address mission redundancy and safety requirements. A high level system perspective was maintained to avoid focusing solely on individual component optimization at the expense of system level performance, operability, and development cost.

  1. Thermal comfort

    DEFF Research Database (Denmark)

    d’Ambrosio Alfano, Francesca Romana; Olesen, Bjarne W.; Palella, Boris Igor;

    2014-01-01

    Thermal comfort is one of the most important aspects of the indoor environmental quality due to its effects on well-being, people's performance and building energy requirements. Its attainment is not an easy task requiring advanced design and operation of building and HVAC systems, taking...... into account all parameters involved. Even though thermal comfort fundamentals are consolidated topics for more than forty years, often designers seem to ignore or apply them in a wrong way. Design input values from standards are often considered as universal values rather than recommended values to be used...... under specific conditions. At operation level, only few variables are taken into account with unpredictable effects on the assessment of comfort indices. In this paper, the main criteria for the design and assessment of thermal comfort are discussed in order to help building and HVAC systems designers...

  2. Impact of Clocking on the Aero-Thermodynamics of a Second Stator tested in a One and a Half Stage HP Turbine

    Institute of Scientific and Technical Information of China (English)

    N. Billiard; G. Paniagua; R. Dénos

    2008-01-01

    This paper focuses on the experimental investigation of the time-averaged and time-accurate aero-thermodynamics of a second stator tested in a 1.5 stage high-pressure turbine. The effect of clocking on aerodynamic and heat transfer are investigated. Tests are performed under engine representative conditions in the VKI compression tube CT3. The test program includes four different clocking positions, i.e. relative pitch-wise positions between the first and the second stator. Probes located upstream and downstream of the second stator provide the thermodynamic conditions of the flow field. On the second stator airfoil, measurements are taken around the blade profile at 15, 50 and 85% span with pressure sensors and thin-film gauges. Both time-averaged and time-resolved aspects of the flow field are addressed. Regarding the time-averaged results, clocking effects are mainly observed within the leading edge region of the second stator, the largest effects being observed at 15% span. The surface static pressure distribution is changed locally, hence affecting the overall airfoil performance. For one clocking position,the thermal load of the airfoil is noticeably reduced. Pressure fluctuations are attributed to the passage of the upstream transonic rotor and its associated pressure gradients. The pattern of these fluctuations changes noticeably as a function of docking. The time-resolved variations of heat flux and static pressure are analyzed together showing that the major effect is due to a potential interaction. The time-resolved pressure distribution integrated along the second stator surface yields the unsteady forces on the vane. The magnitude of the unsteady force is very dependent on the clocking position.

  3. On observation of the downconversion mechanism in Er{sup 3+}/Yb{sup 3+} co-doped tellurite glass using thermal and optical parameters

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, M.S.; Santos, F.A. [Universidade Federal da Grande Dourados, Faculdade de Ciências Exatas e Tecnologias, Dourados, MS (Brazil); Yukimitu, K.; Moraes, J.C.S. [Universidade Estadual Paulista, UNESP, Departamento de Física e Química, Av. Brasil, 56, 15385-000 Ilha Solteira, SP (Brazil); Nunes, L.A.O. [Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, SP (Brazil); Andrade, L.H.C. [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul, Cidade Universitária de Dourados, CP 351, Dourados, MS (Brazil); Lima, S.M., E-mail: smlima@uems.br [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul, Cidade Universitária de Dourados, CP 351, Dourados, MS (Brazil)

    2015-01-15

    In this work we report the observed downconversion (DC) mechanism in Er{sup 3+}/Yb{sup 3+}-codoped tellurite glasses (in mol%, 80TeO{sub 2}–10Li{sub 2}O–10TiO{sub 2}). The samples were synthesized by the conventional melt-quenching method and then studied using optical spectroscopy and thermal lens spectroscopy (TLS). These characterizations enabled investigation of the radiative and nonradiative processes involved in energy transfer from erbium to ytterbium. The visible Er{sup 3+} fluorescence intensities decreased as a function of the Yb{sup 3+} concentration, and there was a corresponding increase in the ytterbium emission at around 980 nm. Simultaneously, there was a reduction in the heat-generated due nonradiative decays (∼21%) when ytterbium was added. This temperature change was measured by TLS measurements and the results corroborate with the indicated by spectroscopic interpretation. - Highlights: • Energy transfer from erbium to ytterbium in tellurite glass. • ∼56% of cross-relaxation efficiency from Er{sup 3+} to Yb{sup 3+}. • Downconversion effect in tellurite glasses. • Downconversion effect observation by thermal lens spectroscopy.

  4. An overview on novel thermal barrier coatings

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Thermal barrier coatings (TBCs) offer the potential to significantly improve efficiencies of aero engines as well as stationary gas turbines for power generation. On internally cooled turbine parts, temperature gradients of the order of 100-150℃ can be achieved. TBCs, typically consisting of an yttrium stabilized zirconia top coat and a metallic bond coat deposited onto a superalloy substrate, are mainly used to extend lifetime. Further efficiency improvements require TBCs being an integral part of the component which requires reliable and predictable TBC performance. TBCs produced by electron beam physical vapor deposition (EbPVD) or plasma spray (PS) deposition are favored for high performance applications. The paper highlights critical R&D needs for advanced TBC systems with a special focus on reduced thermal conductivity and life prediction needs. To further enhance the efficiency of gas turbines, higher temperature and a longer lifetime of the coating are needed for the next generation of TBCs. This paper presents the development of new materials, new deposition technologies, and new concept for application as novel TBCs. This paper summarizes the basic properties of conventional thermal barrier coatings. Based on our own investigation, we reviewed the progress on materials and technologies of novel thermal barrier coatings. Except yttria stabilized zirconia, other materials such as lanthanum zirconate and rare earth oxides are also promising materials for thermal barrier coatings. Nanostructure thermal barrier coating is presented as a new concept. This paper also summarizes the technologies for depositing the thermal barrier coatings.

  5. Calibration of aero-structural reduced order models using full-field experimental measurements

    Science.gov (United States)

    Perez, R.; Bartram, G.; Beberniss, T.; Wiebe, R.; Spottswood, S. M.

    2017-03-01

    The structural response of hypersonic aircraft panels is a multi-disciplinary problem, where the nonlinear structural dynamics, aerodynamics, and heat transfer models are coupled. A clear understanding of the impact of high-speed flow effects on the structural response, and the potential influence of the structure on the local environment, is needed in order to prevent the design of overly-conservative structures, a common problem in past hypersonic programs. The current work investigates these challenges from a structures perspective. To this end, the first part of this investigation looks at the modeling of the response of a rectangular panel to an external heating source (thermo-structural coupling) where the temperature effect on the structure is obtained from forward looking infrared (FLIR) measurements and the displacement via 3D-digital image correlation (DIC). The second part of the study uses data from a previous series of wind-tunnel experiments, performed to investigate the response of a compliant panel to the effects of high-speed flow, to train a pressure surrogate model. In this case, the panel aero-loading is obtained from fast-response pressure sensitive paint (PSP) measurements, both directly and from the pressure surrogate model. The result of this investigation is the use of full-field experimental measurements to update the structural model and train a computational efficient model of the loading environment. The use of reduced order models, informed by these full-field physical measurements, is a significant step toward the development of accurate simulation models of complex structures that are computationally tractable.

  6. 基于迭代估计的三轴加速度计温度模型参数外场标定方法%Field calibration for thermal parameters of triaxial accelerometers based on iterative estimation method

    Institute of Scientific and Technical Information of China (English)

    杨杰; 吴文启; 练军想; 刘伟

    2013-01-01

    为补偿加速度计标度因数和零偏的热漂移误差,设计了一种可估计内场恒温环境下参数变化量的加速度计温度参数模型,并提出了基于迭代估计的温度模型参数外场标定方法。该方法不依赖精密的惯性测量设备和温箱,仅在重力场内对加速度计进行连续多组位置观测,充分利用加速度计冷启动过程产生的热漂移误差进行模型参数辨识,解决了加速度计温度误差特性和启动温度点相关的问题。针对加速度计测量信号为高斯白噪声的特点,建立了关于温度模型参数矢量和多组位置倾斜矢量的非线性准则函数,提出了两步迭代估计方法实现两组参数矢量的分离估计。根据不同位置下三轴加速度计输出信号粗略提取倾斜矢量,解决了迭代估计算法的初值问题。重力场内通过优化分析加速度计温度模型参数对重力值的灵敏度,设计了6组位置观测编排。实验结果表明,温度误差补偿前的重力值测量最大误差为3.62×10-4g,而温度误差补偿后重力值测量误差小于1×10-5g;同时,温度误差补偿前系统3 h纯惯性导航最大定位误差为1186 m,而温度误差补偿后最大定位误差小于600 m,从而表明提出的外场标定方法的有效性。%In order to reduce the thermal drift errors of scale factors and biases, the thermal model of triaxial accelerometers is established whereby the alteration of internal-field constant-temperature parameters is also compensated. An iterative estimation based field calibration method is proposed to solve the thermal parameters. First, no precise inertial test facilities and incubators are utilized in the calibration procedure. Second, the sequential multi-position gravitational observation is implemented on the accelerometers in the after-power-on procedure. Thus, the thermal parameters dependent on the startup temperature is estimated by the above thermal

  7. LSE investigation of the thermal effect on band gap energy and thermodynamic parameters of BInGaAs/GaAs Single Quantum Well

    Science.gov (United States)

    Hidouri, T.; Saidi, F.; Maaref, H.; Rodriguez, Ph.; Auvray, L.

    2016-12-01

    In this paper, we report on the experimental and theoretical study of BInGaAs/GaAs Single Quantum Well elaborated by Metal Organic Chemical Vapor Deposition (MOCVD). We carried out the photoluminescence (PL) peak energy temperature-dependence over a temperature range of 10-300 K. It shows the S-shaped behavior as a result of a competition process between localized and delocalized states. We simulate the peak evolution by the empirical model and modified models. The first one is limited at high PL temperature. For the second one, a correction due to the thermal redistribution based on the Localized State Ensemble model (LSE). The new fit gives a good agreement between theoretical and experimental data in the entire temperature range. Furthermore, we have investigated an approximate analytical expressions and interpretation for the entropy and enthalpy of formation of electron-hole pairs in quaternary BInGaAs/GaAs SQW.

  8. Narrow band imaging and high definition television in the endoscopic evaluation of upper aero-digestive tract cancer.

    Science.gov (United States)

    Piazza, C; Cocco, D; Del Bon, F; Mangili, S; Nicolai, P; Peretti, G

    2011-04-01

    Narrow band imaging and high definition television are recent innovations in upper aero-digestive tract endoscopy. Aim of this prospective, non-randomized, unblinded study was to establish the diagnostic advantage of these procedures in the evaluation of squamous cell cancer arising from various upper aero-digestive tract sites. Between April 2007 and January 2010, 444 patients affected by upper aero-digestive tract squamous cell cancer, or previously treated for it, were evaluated by white light and narrow band imaging ± high definition television endoscopy, both in the pre-/intra-operative setting and during follow-up. Tumour resection was performed taking into account narrow band imaging and high definition television information to obtain histopathologic confirmation of their validity. Endoscopic and pathologic data were subsequently matched to obtain sensitivity, specificity, positive, negative predictive values, and accuracy. Overall, 110 (25%) patients showed adjunctive findings by narrow band imaging ± high definition television when compared to standard white light endoscopy. Of these patients, 98 (89%) received histopatological confirmation. The sensitivity, specificity, positive, negative predictive values, and accuracy for white light-high definition television were 41%, 92%, 87%, 82%, and 67%, for narrow band imaging alone 75%, 87%, 87%, 74%, and 80%, and for narrow band imaging-high definition television 97%, 84%, 88%, 96%, and 92%. The highest diagnostic gain was observed in the oral cavity and oropharynx (25%). Narrow band imaging and high definition television were of value in the definition of superficial tumour extension, and in the detection of synchronous lesions in the pre-/intra-operative settings. These technologies also played an important role during post-treatment surveillance for early detection of persistences, recurrences, and metachronous tumours.

  9. Spectrally resolved modulated infrared radiometry of photothermal, photocarrier, and photoluminescence response of CdSe crystals: Determination of optical, thermal, and electronic transport parameters

    Energy Technology Data Exchange (ETDEWEB)

    Pawlak, M., E-mail: mpawlak@fizyka.umk.pl [Institute of Physics, Nicolaus Copernicus University, Grudziadzka, 87-100 Torun (Poland); Chirtoc, M.; Horny, N. [Multiscale Thermophysics Lab. GRESPI, Université de Reims Champagne Ardenne URCA, Moulin de la Housse BP 1039, 51687 Reims (France); Pelzl, J. [Institut für Experimentalphysik VI, Ruhr-Universität Bochum, 44801 Bochum (Germany)

    2016-03-28

    Spectrally resolved modulated infrared radiometry (SR-MIRR) with super-band gap photoexcitation is introduced as a self-consistent method for semiconductor characterization (CdSe crystals grown under different conditions). Starting from a theoretical model combining the contributions of the photothermal (PT) and photocarrier (PC) signal components, an expression is derived for the thermal-to-plasma wave transition frequency f{sub tc} which is found to be wavelength-independent. The deviation of the PC component from the model at high frequency is quantitatively explained by a quasi-continuous distribution of carrier recombination lifetimes. The integral, broad frequency band (0.1 Hz–1 MHz) MIRR measurements simultaneously yielded the thermal diffusivity a, the effective IR optical absorption coefficient β{sub eff}, and the bulk carrier lifetime τ{sub c}. Spectrally resolved frequency scans were conducted with interchangeable IR bandpass filters (2.2–11.3 μm) in front of the detector. The perfect spectral match of the PT and PC components is the direct experimental evidence of the key assumption in MIRR that de-exciting carriers are equivalent to blackbody (Planck) radiators. The exploitation of the β spectrum measured by MIRR allowed determining the background (equilibrium) free carrier concentration n{sub 0}. At the shortest wavelength (3.3 μm), the photoluminescence (PL) component supersedes the PC one and has distinct features. The average sample temperature influences the PC component but not the PT one.

  10. Numerical Prediction of Flow and Heat Transfer on lubricant Supplying and Scavenging Flow Path of an Aero-Engine Lubrication System

    Science.gov (United States)

    Huang, S. Q.; Liu, Z. X.; Lv, Y. G.; Zhang, L. F.; Xu, T.

    This paper presents a numerical model of internal flows on lubricant supplying and scavenging flow path of an aero-engine lubrication system. The numerical model was built in the General Analysis Software of Aero-engine Lubrication System (GASLS), developed by Northwestern Polytechnical University. The lubricant flow flux, pressure and temperature distribution at steady state were calculated. GASLS is a general purpose computer program employed a ID steady state network algorithm for analyzing flowrates, pressures and temperatures in a complex flow network. All kinds of aero-engine lubrication systems can be divided into finite correlative typical elements and nodes from which the calculation network is developed in GASLS. Special emphasis is put on how to use combinational elements which is a type of typical elements to replace some complex components such as bearing compartments, accessory drive gearboxes or heat exchangers. This method can reduce network complexity and improve calculation efficiency. The computational results show good agreement with experimental data.

  11. PARAMETER KINETIKA INAKTIVASI TERMAL DAN ISOLASI Staphylococcus aureus PADA MINUMAN DARI GEL CINCAU HIJAU DAN ROSELA [Thermal Inactivation Kinetics Parameter and Isolation of Staphylococcus aureus on Drink from Green Grass Jelly and Roselle

    Directory of Open Access Journals (Sweden)

    Eko Hari Purnomo

    2015-07-01

    Full Text Available Information about heat resistance (D and z values of target bacteria is needed for the thermal process design on drink from Green Grass Jelly (Premna oblongifolia Merr. and Roselle (Hibiscus sabdariffa L., so it can guarantee quality and safety of the product. The objectives of this research were to isolate Staphylococcus aureus from commercial green grass jelly and to determine the D and z values of Staphylococcus aureus (from commercial product and standard clinical isolate ATCC 25923 on heating menstruum of green grass jelly and roselle. Isolation of S. aureus was done by inoculation in selective medium, D and z values of Staphylococcus aureus were assessed by heating at constant temperatures of 57, 53, 49, and 45°C during the time interval 2.5, 5, 10, and 15 minutes. The results showed that one isolate (Isolate A gave positive response of Staphylococcus aureus in isolation tests and had similar percentage with the reference culture of 41.8% using the API Staph Kit. Heat resistance of Staphylococcus aureus (represented as D value isolated from green grass jelly at constant heating temperature of D45, D49, D53 and D57 were 32.3, 17.9, 4.6, and 1.5 minutes. On the other hand, D value of isolates ATCC 25923 (standard clinical isolate at constant heating temperature of D45, D49, D53 and D57 were 18.5, 6.8, 2.9, and 1.4 minutes. The z value of isolates A and ATCC 25923 were 8.8°C and 10.8°C. Smaller z value of isolate A showed that pasteurization process can be accelerated and optimized with increasing the temperature slightly but has the same lethality effect.

  12. On improving Efficiency and Accuracy of Variable-Fidelity Surrogate Modeling in Aero-data for Loads Context

    DEFF Research Database (Denmark)

    Han, Zhonghua; Zimmermann, Ralf; Goertz, Stefan

    2009-01-01

    ) and a generalized hybrid bridge function, have been developed to improve the efficiency and accuracy of the existing Variable-Fidelity Modeling (VFM) approach. These new algorithms and features are demonstrated and evaluated for analytical functions and used to construct a global surrogate model for the aerodynamic......Variable-fidelity surrogate modeling offers an efficient way to generate aerodynamic data for aero-loads prediction based on a set of CFD methods with varying degree of fidelity and computational expense. In this paper, new algorithms, such as a Gradient-Enhanced Kriging method (direct GEK...

  13. Small wind turbine performance evaluation using field test data and a coupled aero-electro-mechanical model

    Science.gov (United States)

    Wallace, Brian D.

    A series of field tests and theoretical analyses were performed on various wind turbine rotor designs at two Penn State residential-scale wind-electric facilities. This work involved the prediction and experimental measurement of the electrical and aerodynamic performance of three wind turbines; a 3 kW rated Whisper 175, 2.4 kW rated Skystream 3.7, and the Penn State designed Carolus wind turbine. Both the Skystream and Whisper 175 wind turbines are OEM blades which were originally installed at the facilities. The Carolus rotor is a carbon-fiber composite 2-bladed machine, designed and assembled at Penn State, with the intent of replacing the Whisper 175 rotor at the off-grid system. Rotor aerodynamic performance is modeled using WT_Perf, a National Renewable Energy Laboratory developed Blade Element Momentum theory based performance prediction code. Steady-state power curves are predicted by coupling experimentally determined electrical characteristics with the aerodynamic performance of the rotor simulated with WT_Perf. A dynamometer test stand is used to establish the electromechanical efficiencies of the wind-electric system generator. Through the coupling of WT_Perf and dynamometer test results, an aero-electro-mechanical analysis procedure is developed and provides accurate predictions of wind system performance. The analysis of three different wind turbines gives a comprehensive assessment of the capability of the field test facilities and the accuracy of aero-electro-mechanical analysis procedures. Results from this study show that the Carolus and Whisper 175 rotors are running at higher tip-speed ratios than are optimum for power production. The aero-electro-mechanical analysis predicted the high operating tip-speed ratios of the rotors and was accurate at predicting output power for the systems. It is shown that the wind turbines operate at high tip-speeds because of a miss-match between the aerodynamic drive torque and the operating torque of the wind

  14. Dual-frequency Eddy Current Non-destructive Detection of Fatigue Cracks in Compressor Discs of Aero Engines

    Directory of Open Access Journals (Sweden)

    B. Sasi

    2004-10-01

    Full Text Available Eddy current non-destructive testing is used to inspect the critical aircraft components. The shortcomings of the inspection method identified, based on a few accidents, necessitatethe development of high sensitive and reliable testing procedures for inspecting the critical safety related aircraft components. This paper discusses a dual-frequency eddy current testingprocedure developed for inspection of compressor discs of aero engines for detecting fatigue cracks with high sensitivity and reliability. This procedure is capable of detecting fatigue crackssmaller than 2 mm in comparison to 4 mm cracks that can be detected with the currently practiced eddy current testing procedure.

  15. Smart rotor modeling aero-servo-elastic modeling of a smart rotor with adaptive trailing edge flaps

    CERN Document Server

    Bergami, Leonardo

    2014-01-01

    A smart rotor is a wind turbine rotor that, through a combination of sensors, control units and actuators actively reduces the variation of the aerodynamic loads it has to withstand. Smart rotors feature?promising load alleviation potential and might provide the technological breakthrough required by the next generation of large wind turbine rotors.The book presents the aero-servo-elastic model of a smart rotor with Adaptive Trailing Edge Flaps for active load alleviation and provides an insight on the rotor aerodynamic, structural and control modeling. A novel model for the unsteady aerodynam

  16. Smoking and the Risk of Upper Aero Digestive Tract Cancers for Men and Women in the Asia-Pacific Region

    Directory of Open Access Journals (Sweden)

    Mark Woodward

    2009-04-01

    Full Text Available Although smoking is an established causal factor for upper aero digestive tract cancer (UADTC, most of the evidence originates from the West. Thus, we analysed data from 455,409 subjects in the Asia Pacific Cohort Studies Collaboration. Over a median of around six years follow-up, 371 deaths from UADTC were observed. The hazard ratio (95% confidence interval for current smokers, compared with those who had never smoked, was 2.36 (1.76 – 3.16, adjusted for age and alcohol drinking. Tobacco control policies are urgently required in Asia to prevent millions of deaths from UADTC that smoking will otherwise cause.

  17. PREFACE: The 2nd International Conference on Geological, Geographical, Aerospace and Earth Sciences 2014 (AeroEarth 2014)

    Science.gov (United States)

    Lumban Gaol, Ford; Soewito, Benfano

    2015-01-01

    The 2nd International Conference on Geological, Geographical, Aerospace and Earth Sciences 2014 (AeroEarth 2014), was held at Discovery Kartika Plaza Hotel, Kuta, Bali, Indonesia during 11 - 12 October 2014. The AeroEarth 2014 conference aims to bring together researchers and engineers from around the world. Through research and development, earth scientists have the power to preserve the planet's different resource domains by providing expert opinion and information about the forces which make life possible on Earth. Earth provides resources and the exact conditions to make life possible. However, with the advent of technology and industrialization, the Earth's resources are being pushed to the brink of depletion. Non-sustainable industrial practices are not only endangering the supply of the Earth's natural resources, but are also putting burden on life itself by bringing about pollution and climate change. A major role of earth science scholars is to examine the delicate balance between the Earth's resources and the growing demands of industrialization. Through research and development, earth scientists have the power to preserve the planet's different resource domains by providing expert opinion and information about the forces which make life possible on Earth. We would like to express our sincere gratitude to all in the Technical Program Committee who have reviewed the papers and developed a very interesting Conference Program as well as the invited and plenary speakers. This year, we received 98 papers and after rigorous review, 17 papers were accepted. The participants come from eight countries. There are four Parallel Sessions and two invited Speakers. It is an honour to present this volume of IOP Conference Series: Earth and Environmental Science (EES) and we deeply thank the authors for their enthusiastic and high-grade contributions. Finally, we would like to thank the conference chairmen, the members of the steering committee, the organizing committee

  18. Optimal parameters for the FFA-Beddoes dynamic stall model

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerck, A.; Mert, M. [FFA, The Aeronautical Research Institute of Sweden, Bromma (Sweden); Madsen, H.A. [Risoe National Lab., Roskilde (Denmark)

    1999-03-01

    Unsteady aerodynamic effects, like dynamic stall, must be considered in calculation of dynamic forces for wind turbines. Models incorporated in aero-elastic programs are of semi-empirical nature. Resulting aerodynamic forces therefore depend on values used for the semi-empiricial parameters. In this paper a study of finding appropriate parameters to use with the Beddoes-Leishman model is discussed. Minimisation of the `tracking error` between results from 2D wind tunnel tests and simulation with the model is used to find optimum values for the parameters. The resulting optimum parameters show a large variation from case to case. Using these different sets of optimum parameters in the calculation of blade vibrations, give rise to quite different predictions of aerodynamic damping which is discussed. (au)

  19. SUPERALLOYS: AN INTRODUCTION WITH THERMAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    S. S. Raza

    2015-09-01

    Full Text Available Nickel based superalloys are commonly used materials in the aero industry and more specifically in the hot section of aero engines. These nickel and nickel iron based superalloys are precipitation strengthened alloys with a face centered cubic gamma matrix. Alloy 718, Allvac 718Plus and Waspaloy have been of great interest in the present study. Alloy 718 is a precipitation strengthened nickel-iron based alloy having gamma double prime phase (Ni3Nb as a main strengthening phase up to 650 °C. Waspaloy, another precipitation strengthened nickel base superalloy, has a very good strength at temperatures up to ~750 °C whereas Allvac 718Plus is a newly developed nickel based precipitation strengthened superalloy which retains good mechanical properties at up to ~700 °C. These three alloys were investigated in terms of how their respective solidification process reveals upon cooling.Latent heat of soloidification has been estimated for all three alloys. Differential thermal analyses (DTA have been used to approach the task. It was seen that Waspaloy has the smallest solidification range whereas Allvac 718Plus has the largest solidification interval in comparison. 

  20. Influence of Clothing Insulation on Indoor Thermal Comfort Parameters in Different Climate%基于气候的服装热阻对室内热舒适参数的影响

    Institute of Scientific and Technical Information of China (English)

    汤振宇; 葛凤华; 王剑; 陆翠银; 任奎

    2016-01-01

    For characteristic of people’s dress in different climatic regions, the relationship between the outdoor temperature and indoor clothing insulation is analyzed in heating conditions in winter. It is proposed that clothing insulation is an important factor affecting indoor thermal comfort parameters in thermal adaptation model. The influence between PMV and clothing insulation after entering room is expounded, as well as the significance of changing clothing insulation to save energy. The impact of clothing insulation on PMV is calculated under different conditions using P. O. Fanger’s thermal comfort equation, and the range of indoor temperature, air velocity and humidity are decided in different climatic regions. It presents the correction method of indoor design parameters, considering the impact of climate on outdoor clothing insulation.%针对不同气候地区人们的着装特点,分析了在冬季供暖条件下,室外温度与室内服装热阻的关系,提出在热适应模型中,服装热阻是影响室内热舒适参数的重要因素,分析进入室内后服装对PMV的影响,以及改变服装热阻对建筑节能的意义。利用P. O. Fanger的热舒适方程,计算不同条件下服装热阻对PMV的影响,得到不同气候地区室内热中性时的设计温度、平均辐射温度、空气流速和湿度的取值范围,并提出考虑室外气候对服装热阻有影响时室内设计参数的修正方法。

  1. Modeling C-Band Co-Channel Interference From AeroMACS Omni-Directional Antennas to Mobile Satellite Service Feeder Uplinks

    Science.gov (United States)

    Wilson, Jeffrey D.

    2011-01-01

    A new C-band (5091 to 5150 MHz) airport communications system designated as Aeronautical Mobile Airport Communications System (AeroMACS) is being planned under the Federal Aviation Administration s NextGen program. An interference analysis software program, Visualyse Professional (Transfinite Systems Ltd), is being utilized to provide guidelines on limitations for AeroMACS transmitters to avoid interference with other systems. A scenario consisting of a single omni-directional transmitting antenna at each of the major contiguous United States airports is modeled and the steps required to build the model are reported. The results are shown to agree very well with a previous study.

  2. Optical parameters of ternary Te{sub 15}(Se{sub 100-x}Bi{sub x}){sub 85} thin films deposited by thermal evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Kameshwar; Thakur, Nagesh [Department of Physics, HP University, Shimla 171005 (India); Sharma, Pankaj [Department of Physics, Jaypee University of Information Technology, Waknaghat, Solan, HP 173215 (India); Katyal, S C, E-mail: kameshwarkumar01@gmail.com, E-mail: pankaj.sharma@juit.ac.in, E-mail: ntb668@yahoo.co.in [Department of Physics, Jaypee Institute of Information Technology, Noida, UP (India)

    2011-10-15

    Thin films of Te{sub 15}(Se{sub 100-x}Bi{sub x}){sub 85} (x=0, 1, 2, 3, 4 and 5 at.%) glassy alloys were deposited by thermal evaporation (at 10{sup -4} Pa) from bulk samples. Optical characterization of the films was done by analysing their transmission spectra taken in the spectral range 400-2300 nm. Swanepoel's method was used to calculate the refractive index (n) and extinction coefficient (k). It was found that the refractive index increases with an increase in Bi content. The Wemple-DiDomenico single-oscillator approach was used to calculate the average band gap energy (E{sub o}), dispersion energy (E{sub d}) and static refractive index (n{sub o}). The absorption coefficient ({alpha}) and film thickness were calculated from the transmission spectra of the films. The optical band gap (E{sub g}) was estimated using Tauc's extrapolation and was found to decrease from 1.37 to 1.21 eV with Bi addition from 0 to 5 at.% in glassy alloys. The decrease in optical band gap is explained on the basis of the decrease in cohesive energy of the samples and the difference of electronegativity of the atoms involved. The real ({epsilon}{sub r}) and imaginary parts ({epsilon}{sub i}) of the dielectric constant for the films were also calculated and reported.

  3. Effects of the electrical excitation signal parameters on the geometry of an argon-based non-thermal atmospheric pressure plasma jet.

    Science.gov (United States)

    Benabbas, Mohamed Tahar; Sahli, Salah; Benhamouda, Abdallah; Rebiai, Saida

    2014-12-01

    A non-thermal atmospheric pressure argon plasma jet for medical applications has been generated using a high-voltage pulse generator and a homemade dielectric barrier discharge (DBD) reactor with a cylindrical configuration. A plasma jet of about 6 cm of length has been created in argon gas at atmospheric pressure with an applied peak to peak voltage and a frequency of 10 kV and 50 kHz, respectively. The length and the shape of the created plasma jet were found to be strongly dependent on the electrode setup and the applied voltage and the signal frequency values. The length of the plasma jet increases when the applied voltage and/or its frequency increase, while the diameter at its end is significantly reduced when the applied signal frequency increases. For an applied voltage of 10 kV, the plasma jet diameter decreases from near 5 mm for a frequency of 10 kHz to less than 1 mm at a frequency of 50 kHz. This obtained size of the plasma jet diameter is very useful when the medical treatment must be processed in a reduced space. PACS 2008: 52.50.Dg; 52.70.-m; 52.80.-s.

  4. Modeled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    Science.gov (United States)

    Samset, B. H.; Myhre, G.; Herber, A.; Kondo, Y.; Li, S.-M.; Moteki, N.; Koike, M.; Oshima, N.; Schwarz, J. P.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Berntsen, T. K.; Bian, H.; Chin, M.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2014-08-01

    Atmospheric black carbon (BC) absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF). However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparision. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modeled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  5. Modelled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    Science.gov (United States)

    Samset, B. H.; Myhre, G.; Herber, A.; Kondo, Y.; Li, S.-M.; Moteki, N.; Koike, M.; Oshima, N.; Schwarz, J. P.; Balkanski, Y.; Bauer, S. E.; Bellouin, N.; Berntsen, T. K.; Bian, H.; Chin, M.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kirkevåg, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Schulz, M.; Seland, Ø.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2014-11-01

    Atmospheric black carbon (BC) absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF). However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long-range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present-day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparison. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modelled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  6. Modeled black carbon radiative forcing and atmospheric lifetime in AeroCom Phase II constrained by aircraft observations

    Directory of Open Access Journals (Sweden)

    B. H. Samset

    2014-08-01

    Full Text Available Atmospheric black carbon (BC absorbs solar radiation, and exacerbates global warming through exerting positive radiative forcing (RF. However, the contribution of BC to ongoing changes in global climate is under debate. Anthropogenic BC emissions, and the resulting distribution of BC concentration, are highly uncertain. In particular, long range transport and processes affecting BC atmospheric lifetime are poorly understood. Here we discuss whether recent assessments may have overestimated present day BC radiative forcing in remote regions. We compare vertical profiles of BC concentration from four recent aircraft measurement campaigns to simulations by 13 aerosol models participating in the AeroCom Phase II intercomparision. An atmospheric lifetime of BC of less than 5 days is shown to be essential for reproducing observations in remote ocean regions, in line with other recent studies. Adjusting model results to measurements in remote regions, and at high altitudes, leads to a 25% reduction in AeroCom Phase II median direct BC forcing, from fossil fuel and biofuel burning, over the industrial era. The sensitivity of modeled forcing to BC vertical profile and lifetime highlights an urgent need for further flight campaigns, close to sources and in remote regions, to provide improved quantification of BC effects for use in climate policy.

  7. Effective L/D: A Theoretical Approach to the Measurement of Aero-Structural Efficiency in Aircraft Design

    Science.gov (United States)

    Guynn, Mark D.

    2015-01-01

    There are many trade-offs in aircraft design that ultimately impact the overall performance and characteristics of the final design. One well recognized and well understood trade-off is that of wing weight and aerodynamic efficiency. Higher aerodynamic efficiency can be obtained by increasing wing span, usually at the expense of higher wing weight. The proper balance of these two competing factors depends on the objectives of the design. For example, aerodynamic efficiency is preeminent for sailplanes and long slender wings result. Although the wing weight-drag trade is universally recognized, aerodynamic efficiency and structural efficiency are not usually considered in combination. This paper discusses the concept of "aero-structural efficiency," which combines weight and drag characteristics. A metric to quantify aero-structural efficiency, termed effective L/D, is then derived and tested with various scenarios. Effective L/D is found to be a practical and robust means to simultaneously characterize aerodynamic and structural efficiency in the context of aircraft design. The primary value of the effective L/D metric is as a means to better communicate the combined system level impacts of drag and structural weight.

  8. Ray tracing simulation of aero-optical effect using multiple gradient index layer

    Science.gov (United States)

    Yang, Seul Ki; Seong, Sehyun; Ryu, Dongok; Kim, Sug-Whan; Kwon, Hyeuknam; Jin, Sang-Hun; Jeong, Ho; Kong, Hyun Bae; Lim, Jae Wan; Choi, Jong Hwa

    2016-10-01

    We present a new ray tracing simulation of aero-optical effect through anisotropic inhomogeneous media as supersonic flow field surrounds a projectile. The new method uses multiple gradient-index (GRIN) layers for construction of the anisotropic inhomogeneous media and ray tracing simulation. The cone-shaped projectile studied has 19° semi-vertical angle; a sapphire window is parallel to the cone angle; and an optical system of the projectile was assumed via paraxial optics and infrared image detector. The condition for the steady-state solver conducted through computational fluid dynamics (CFD) included Mach numbers 4 and 6 in speed, 25 km altitude, and 0° angle of attack (AoA). The grid refractive index of the flow field via CFD analysis and Gladstone-Dale relation was discretized into equally spaced layers which are parallel with the projectile's window. Each layer was modeled as a form of 2D polynomial by fitting the refractive index distribution. The light source of ray set generated 3,228 rays for varying line of sight (LOS) from 10° to 40°. Ray tracing simulation adopted the Snell's law in 3D to compute the paths of skew rays in the GRIN layers. The results show that optical path difference (OPD) and boresight error (BSE) decreases exponentially as LOS increases. The variation of refractive index decreases, as the speed of flow field increases the OPD and its rate of decay at Mach number 6 in speed has somewhat larger value than at Mach number 4 in speed. Compared with the ray equation method, at Mach number 4 and 10° LOS, the new method shows good agreement, generated 0.33% of relative root-mean-square (RMS) OPD difference and 0.22% of relative BSE difference. Moreover, the simulation time of the new method was more than 20,000 times faster than the conventional ray equation method. The technical detail of the new method and simulation is presented with results and implication.

  9. 直升机气动噪声研究进展%Progress in aero-acoustic technology of helicopter

    Institute of Scientific and Technical Information of China (English)

    陈平剑; 仲唯贵; 段广战

    2015-01-01

    The status and progress in helicopter aero-acoustic technology is presented,inclu-ding test technology,analysis method and rotor noise control technology.The advanced test technologies such as unsteady pressure measurement,flow field visualization and noise source lo-calization,have been implemented in the acoustic wind tunnel test of rotor noise,which is the es-sential instrument for helicopter aero-acoustic research.Flight test of helicopter aero-acoustic measurements has become a necessary technique in the programs of helicopter noise certification and helicopter noise reduction investigation.With the development of helicopter aero-acoustic noise analysis method,many software tools for rotor noise prediction have been developed and applied in the helicopter design and noise reduction research,based on the solutions of the FW-H equation and Kirchhoff equation.Low noise blade tip is the primary and effective method for heli-copter noise control,and is used widely in helicopter design.Moreover,new technologies such as noise abatement operation and active rotor noise control have been validated by flight test,but have not been used in helicopter design get.Initiated by the demands to design environmentally compatible helicopter,both societies of industry and academia will devote more effort in helicop-ter aero-acoustic technology research.%对直升机气动噪声的研究进展进行了综述,内容包括试验技术、理论分析方法和噪声抑制技术。声学风洞试验是直升机气动噪声研究的基本手段,其中非定常载荷测试、流场显示和声源定位等先进测试技术已实现应用;飞行试验在直升机噪声适航标准完善和噪声控制技术研究等方面已成为必不可少的研究和验证手段。直升机气动噪声的理论体系不断完善,包括声类比法、Kirchhoff/CFD 混合法等旋翼气动噪声分析方法都已形成分析程序,成为直升机研发的有效工具。直升机气动噪声

  10. Thermophysical Parameters of Organic PCM Coconut Oil from T-History Method and Its Potential as Thermal Energy Storage in Indonesia

    Science.gov (United States)

    Silalahi, Alfriska O.; Sukmawati, Nissa; Sutjahja, I. M.; Kurnia, D.; Wonorahardjo, S.

    2017-07-01

    The thermophysical parameters of organic phase change material (PCM) of coconut oil (co_oil) have been studied by analyzing the temperature vs time data during liquid-solid phase transition (solidification process) based on T-history method, adopting the original version and its modified form to extract the values of mean specific heats of the solid and liquid co_oil and the heat of fusion related to phase transition of co_oil. We found that the liquid-solid phase transition occurs rather gradually, which might be due to the fact that co_oil consists of many kinds of fatty acids with the largest amount of lauric acid (about 50%), with relatively small supercooling degree. For this reason, the end of phase transition region become smeared out, although the inflection point in the temperature derivative is clearly observed signifying the drastic temperature variation between the phase transition and solid phase periods. The data have led to the values of mean specific heat of the solid and liquid co_oil that are comparable to the pure lauric acid, while the value for heat of fusion is resemble to those of the DSC result, both from references data. The advantage of co_oil as the potential sensible and latent TES for room-temperature conditioning application in Indonesia is discussed in terms of its rather broad working temperature range due to its mixture composition characteristic.

  11. Analysis on the effect of hypersonic vehicle's optical window on infrared thermal imaging system

    Science.gov (United States)

    Dong, Liquan; Han, Ying; Kong, Lingqin; Liu, Ming; Zhao, Yuejin; Zhang, Li; Li, Yanhong; Tian, Yi; Sa, Renna

    2015-08-01

    According to the aero-thermal effects and aero-thermal radiation effects of the optical window, the thermo-optic effect, the elasto-optical effect and the thermal deformation of the optical window are analyzed using finite element analysis method. Also, the peak value and its location of the point spread function, which is caused by the thermo-optic effect and the dome thermal deformation, are calculated with the variance of time. Furthermore, the temperature gradient influence to the transmission of optical window, the variation trend of transmission as well as optical window radiation with time are studied based on temperature distribution analysis. The simulations results show that: When the incident light is perpendicular to the optical window, image shift is mainly caused by its thermal deformation, and the value of image shift is very small. Image shift is determined only by the angle of the incident light. With a certain incident angle, image shift is not affected by the gradient refractive index change. The optical window transmission is mainly affected by temperature gradient and thus not neglectable to image quality. Therefore, the selection of window cooling methods, needs not only consider the window temperature but try to eliminate the temperature gradient. When calculating the thermal radiation, the optical window should be regarded as volume radiation source instead of surface radiator. The results provide the basis for the optical window design, material selection and the later image processing.

  12. Mitigation method of thermal transient stress by a total analysis of thermal hydraulic and structural phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Kasahara, Naoto [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Jinbo, Masakazu [Toshiba Co., Tokyo (Japan); Hosogai, Hiromi [Joyo Industry Co., Ltd., Tokai, Ibaraki (Japan)

    2002-09-01

    This study proposes a mitigation method of thermal transient loads in fast reactor components by utilizing relationships among plant system parameters and resulting thermal stresses. Conventional design procedure against thermal transient loads has two independent steps: thermal hydraulic analysis to determine conservative thermal transient conditions considering variation of the system parameters and structural analysis to check structural integrity under given conditions. On the other hand, a total analysis procedure of thermal hydraulic and structural phenomena can grasp the relationship among system parameters and thermal stresses. It enables the mitigation of thermal transient loads by adjusting system parameters. (author)

  13. Solid state parameters, structure elucidation, High Resolution X-Ray Diffraction (HRXRD), phase matching, thermal and impedance analysis on L-Proline trichloroacetate (L-PTCA) NLO single crystals.

    Science.gov (United States)

    Kalaiselvi, P; Raj, S Alfred Cecil; Jagannathan, K; Vijayan, N; Bhagavannarayana, G; Kalainathan, S

    2014-11-11

    Nonlinear optical single crystal of L-Proline trichloroacetate (L-PTCA) was successfully grown by Slow Evaporation Solution Technique (SEST). The grown crystals were subjected to single crystal X-ray diffraction analysis to confirm the structure. From the single crystal XRD data, solid state parameters were determined for the grown crystal. The crystalline perfection has been evaluated using high resolution X-ray diffractometer. The frequencies of various functional groups were identified from FTIR spectral analysis. The percentage of transmittance was obtained from UV Visible spectral analysis. TGA-DSC measurements indicate the thermal stability of the crystal. The dielectric constant, dielectric loss and ac conductivity were measured by the impedance analyzer. The DC conductivity was calculated by the cole-cole plot method.

  14. Influence of process parameters on the cavitation resistance of arc thermally sprayed cobalt stainless steel; Influencia dos parametros de processo na resistencia a cavitacao de uma liga inoxidavel com cobalto aspergido a arco

    Energy Technology Data Exchange (ETDEWEB)

    Pukasiewicz, A. [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Capra, A.R.; Chandelier, J. da L. [Instituto de Tecnologia para o Desenvolvimento (LACTEC), Curitiba, PR (Brazil)], e-mail: anderson.geraldo@lactec.org.br; Paredes, R.S.C. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Engenharia Mecanica

    2006-07-01

    In this work the influence of the arc thermal spraying process on the microstructure, oxide volumetric fraction, porosity and cavitation resistance was studied. The characterization was performed by optical and electrical microscopy, microhardness and ultrasonic cavitation test, ASTM G32-96 in AS895HY cobalt stainless steel. The increase in air pressure, 280 to 410 kPa, modified the oxide fraction from 17,2 +- 3,6% to 10,9 +-1,8%, in the samples without pre-heating treatment. With 120 deg C pre-heating treatment the oxide fraction increase from 24,1 +- 2,8% to 12,8 +- 1,9% when the air pressure was modified from 280 to 550 kPa. The mass loss in vibration-induced cavitation were 1,55 and 1,42 mg/h for 410 kPa AS895HY samples, with and without pre heating treatment, and 2,12 mg/h for 280 kPa samples without pre heating treatment. The results showed that the process parameters modified the microstructure and the cavitation resistance of the arc thermal spraying coatings. (author)

  15. Impact of thermal loading and other water quality parameters on the epizootiology of red-sore disease in centrarchids. Progress report, December 1, 1977--November 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Esch, G.W.; Hazen, T.C.

    1978-07-01

    The implications from these studies are varied, sometimes clear and sometimes less so, for many of the results have raised new and even more critical questions. Thus, our data clearly show that Aeromonas hydrophila is the etiological agent for red-sore disease. Furthermore, they suggest that the effects of temperature are twofold, first in increasing the density of the pathogen in the water column and then in affecting the physiology of the host organism to such an extent as to increase the probability of acquiring the pathogen. On the other hand, organic loading, suggested by other investigators as being important in red-sore disease, was not identified as being significant in the present study. However, if organic loading, or any of its consequences, can be shown to induce stress, then it may be as important in other systems as temperature is in Par Pond. Thus it is quite conceivable that it (organic loading), or some other water quality parameter, may create conditions conducive to increasing densities of A. hydrophila while simultaneously producing water quality characteristics which would lead to stress in fish, and then to increasing the probability of fish acquiring red-sore disease. An enigmatic observation (see Hazen, 1978, for details) is that A. hydrophila has been recovered from a variety of habitats throughout the U.S., yet red-sore disease is known to occur only in the southeast. This peculiar distribution pattern raises several important questions regarding the epizootiology of red-sore, not the least of which is the possibility of there existing differentially virulent strains of A. hydrophila and/or more or less susceptible populations of potential hosts in various parts of the country. Other significant questions are related to the variability in amplitude of red-sore disease from one year to the next among bass in Par Pond, the mode of entry of the pathogen into largemouth bass, and the basic, cellular mechanisms of stress in largemouth bass.

  16. Evaluation of the aero-optical properties of the SOFIA cavity by means of computional fluid dynamics and a super fast diagnostic camera

    Science.gov (United States)

    Engfer, Christian; Pfüller, Enrico; Wiedemann, Manuel; Wolf, Jürgen; Lutz, Thorsten; Krämer, Ewald; Röser, Hans-Peter

    2012-09-01

    The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a 2.5 m reflecting telescope housed in an open cavity on board of a Boeing 747SP. During observations, the cavity is exposed to transonic flow conditions. The oncoming boundary layer evolves into a free shear layer being responsible for optical aberrations and for aerodynamic and aeroacoustic disturbances within the cavity. While the aero-acoustical excitation of an airborne telescope can be minimized by using passive flow control devices, the aero-optical properties of the flow are difficult to improve. Hence it is important to know how much the image seen through the SOFIA telescope is perturbed by so called seeing effects. Prior to the SOFIA science fights Computational Fluid Dynamics (CFD) simulations using URANS and DES methods were carried out to determine the flow field within and above the cavity and hence in the optical path in order to provide an assessment of the aero-optical properties under baseline conditions. In addition and for validation purposes, out of focus images have been taken during flight with a Super Fast Diagnostic Camera (SFDC). Depending on the binning factor and the sub-array size, the SFDC is able to take and to read out images at very high frame rates. The paper explains the numerical approach based on CFD to evaluate the aero-optical properties of SOFIA. The CFD data is then compared to the high speed images taken by the SFDC during flight.

  17. Development of mathematical models for the aero derivative and heavy duty gas turbines; Desenvolvimento de modelos matematicos para as turbinas a gas aeroderivativas e heavy duty

    Energy Technology Data Exchange (ETDEWEB)

    Freire, Marcelo; Mendes, Pedro Paulo de C.; Ferreira, Claudio; Passaro, Mauricio Campos; Gomes, Leonardo Vinicius [Escola Federal de Engenharia de Itajuba, MG (Brazil). Dept. de Eletronica]. E-mails: freire_marcelo@hotmail.com; ppaulo@iee.efei.br; claudio@iee.efei.br; mcpassaro@uol.com.br; leonardo@iee.efei.br

    2002-07-01

    This paper develops, implements and simulates simplified mathematical models of multiple shafts, aero derivatives and heavy-duty gas turbines, aiming the subsides for studies of power systems dynamic behaviour. These components are fundamental to an approximated evaluation of the National Integrated System after the new thermoelectric plants are incorporated.

  18. Facility level thermal systems for the Advanced Technology Solar Telescope

    Science.gov (United States)

    Phelps, LeEllen; Murga, Gaizka; Fraser, Mark; Climent, Tània

    2012-09-01

    The management and control of the local aero-thermal environment is critical for success of the Advanced Technology Solar Telescope (ATST). In addition to minimizing disturbances to local seeing, the facility thermal systems must meet stringent energy efficiency requirements to minimize impact on the surrounding environment and meet federal requirements along with operational budgetary constraints. This paper describes the major facility thermal equipment and systems to be implemented along with associated energy management features. The systems presented include the central plant, the climate control systems for the computer room and coudé laboratory, the carousel cooling system which actively controls the surface temperature of the rotating telescope enclosure, and the systems used for active and passive ventilation of the telescope chamber.

  19. Assessment of organic compound exposures, thermal comfort parameters, and HVAC system-driven air exchange rates in public school portable classrooms in California

    Energy Technology Data Exchange (ETDEWEB)

    Shendell, Derek Garth [Univ. of California, Los Angeles, CA (United States)

    2003-01-01

    indoor air guideline ''target level'', and concentrations of most target VOCs were low. O and M questionnaire results suggested insufficient training and communication between custodians and SD offices concerning HVAC systems. Future studies should attempt larger sample sizes and cover larger geographical areas but continue to assess multiple IEQ parameters during occupied hours. Teachers, custodians, and SD staff must be educated on the importance of adequate ventilation with filtered outdoor air.

  20. Procedimiento para el cálculo de los parámetros de un modelo térmico simplificado del motor asincrónico Parameter estimation procedure for an asynchronous motor simplified thermal model

    Directory of Open Access Journals (Sweden)

    Julio R Gómez Sarduy

    2011-06-01

    Full Text Available En este trabajo se presenta un método para estimar las conductancias y capacitancias de un modelo térmico simplificado del motor asincrónico, utilizando una técnica de baja invasividad. El procedimiento permite predecir el incremento de temperatura del estator del motor asincrónico, tanto para régimen dinámico como en condiciones de estabilidad térmica. Se basa en la estimación paramétrica mediante un modelo de referencia, utilizando como optimizador un algoritmo genético (AG. Se logra en definitiva obtener los parámetros del modelo térmico con un ensayo más sencillo que lo requerido por otros métodos experimentales complejos o cálculos analíticos basados en datos de diseño. El procedimiento propuesto se puede llevar a cabo en condiciones propias de la industria y resulta atractivo su empleo en el análisis de calentamiento de estas máquinas. El método se valida a partir de un estudio de caso reportado en la literatura y se aplica a un caso real en la industria, lográndose una buena precisión.In this paper, an asynchronous motor simplified thermal model method for conductances and capacitances estimation is presented. A low invasive technique is used. The developed procedure allows the stator temperature rise prediction, not only for dynamic regimes, but also in case of thermal stability. A parametric estimation is done through a reference model, using a genetic algorithm (GA as optimizing method. The thermal model parameters are finally obtained with an easer experimental work, than the required by other complex experimental methods or by analytical calculations based on design data. The proposed procedure can be carry out in the particular conditions of industrial environment. Its application is specially useful for asynchronous machine thermal analysis. Using the data of a study case reported in literature, the method validation is done, and is applied in an industrial real case, with good precision resulted from it.