WorldWideScience

Sample records for bearing element couples

  1. Selection of contact bearing couple materials for hip prosthesis using finite element analysis under static conditions

    Science.gov (United States)

    Arirajan, K. A.; Chockalingam, K.; Vignesh, C.

    2018-04-01

    Implants are the artificial parts to replace the missing bones or joints in human anatomy to give mechanical support. Hip joint replacement is an important issue in orthopaedic surgery. The main concern limiting the long-run success of the total hip replacement is the limited service life. Hip replacement technique is widely used in replacing the femur head and acetabular cup by materials that are highly biocompatible. The success of the artificial hip replacement depends upon proper material selection, structure, and shape of the hip prosthesis. Many orthopaedic analyses have been tried with different materials, but ended with partial success on the application side. It is a critical task for selecting the best material pair in the hip prosthesis design. This work develops the finite element analysis of an artificial hip implant to study highest von Mises stress, contact pressure and elastic strain occurs for the dissimilar material combination. The different bearing couple considered for the analysis are Metal on Metal, Metal on Plastic, Metal on Ceramic, Ceramic on Plastic, Ceramic on Ceramic combinations. The analysis is carried out at different static positions of a human (i.e) standing, sitting. The results reveals that the combination with metal in contact with plastic (i.e) Titanium femoral head paired with Ultra High Molecular Weight Poly Ethylene acetabular cup reduces maximum von Mises stress and also it gives lowest contact pressure than other combination of bearing couples.

  2. Solid Lubricated Rolling Element Bearings

    Science.gov (United States)

    1979-02-15

    lubricant into uneven patches of varnish . This varnish , along with the file-like action of the exposed ball carbides on the relatively softer races, can...its structure. Fluorine , one of the most reactive elements, reacts with graphite without combustion from about 790’F to 1022°F, forming a grey-colored...to allow for molding and machining after molding. 0 Method 2 (Hughes) Impregnating these dense weaves with a Thermid 600 polyimide varnish

  3. Wear of rolling element bearings in sodium

    International Nuclear Information System (INIS)

    Campbell, C.S.

    1976-01-01

    Rolling element bearings and related mechanisms are attractive for service in liquid sodium but it is not clear what minimum wear rate can be anticipated. For axially loaded angular contact bearings rotation is incompatible with pure rolling on both races and wear arises from the resulting ball spin. The initial pressure distributions and sizes of the contact ellipses can be calculated but will change with bearing wear. However, the most effective distribution for producing wear would be for the full loads to be borne on the tips of the contact areas, whose maximum length is given by examination of the race wear tracks. A calculation on such a basis should set a lower limit for the wear coefficient. Both the torque and instantaneous wear rate of a bearing will be similar functions of the integral over the contact areas of the product of contact pressure and radius from the ball spin axis. A better estimate of wear coefficient should be obtained by relating the average torque, the average wear, the initial torque and the initial wear where the conditions are known. Analysis of tests in sodium at 400 0 C of high speed steel and Stellite bearings by these methods indicates specific wear rates of the order of 10 -15 m 3 /N-m, not unduly out of line with the range of values found in conventional sliding tests

  4. Research of Two Different Impulsive Faults of Rolling Element Bearing

    International Nuclear Information System (INIS)

    Jiang Zhinong; Xing Chenghong; Feng Kun; Gao Jinji

    2012-01-01

    Fans and pumps are key machines in process industries such as petrochemical and petroleum industries. Their faults can be catastrophic and result in costly downtime. Bearing fault is almost the most common fault of fans and pumps as rolling element bearings are widely used in these machines. Hence, condition monitoring and diagnosis of bearings are important. Two different impulsive faults of bearings have been observed and studied in previous research. The first fault presents very clear impulsive symptom in envelope spectrum, but the bearing can work for a long time. The other fault shows relatively indistinct symptom, but the bearing will break down in a short time. To overcome the problems of inaccurate diagnosis, a combinational approach based on an impulsive energy indicator and traditional enveloping analysis is proposed in this paper. This approach discriminate these two faults well and can support the maintenance decision for the machines with rolling element bearings.

  5. Grafting of cellulose by fluorine-bearing silane coupling agents

    International Nuclear Information System (INIS)

    Ly, B.; Belgacem, M.N.; Bras, J.; Brochier Salon, M.C.

    2010-01-01

    The surface of model cellulose fibres, Avicell (AV), as well as that of Whatman paper (WP) was chemically modified with two fluorine-bearing alkoxysilane coupling agents, namely: 3,3,3-trifluoropropyl trimethoxysilane (TFPS) and 1H,1H,2H,2H,perfluorooctyl trimethoxysilane (PFOS). The occurrence of the grafting of soxhlet extracted modified cellulose was confirmed by the presence of silicon and fluorine atoms detected by elemental analysis, X-ray photoelectron spectroscopy and Electron Dispersion Energy/Scanning Electron Microscopy (EDS/SEM). The contact angle measurements showed that, after grafting, the surface of AV and WP samples became totally highly hydrophobic with a contact angle of 140 deg. Thus, the polar contribution to the surface energy of the modified substrates was found to be close to zero. These modified substrate could be interesting for application such as self-cleaning surface, wipes paper, grease barrier paper or for biocomposite with a polar matrix.

  6. Integral finite element analysis of turntable bearing with flexible rings

    Science.gov (United States)

    Deng, Biao; Liu, Yunfei; Guo, Yuan; Tang, Shengjin; Su, Wenbin; Lei, Zhufeng; Wang, Pengcheng

    2018-03-01

    This paper suggests a method to calculate the internal load distribution and contact stress of the thrust angular contact ball turntable bearing by FEA. The influence of the stiffness of the bearing structure and the plastic deformation of contact area on the internal load distribution and contact stress of the bearing is considered. In this method, the load-deformation relationship of the rolling elements is determined by the finite element contact analysis of a single rolling element and the raceway. Based on this, the nonlinear contact between the rolling elements and the inner and outer ring raceways is same as a nonlinear compression spring and bearing integral finite element analysis model including support structure was established. The effects of structural deformation and plastic deformation on the built-in stress distribution of slewing bearing are investigated on basis of comparing the consequences of load distribution, inner and outer ring stress, contact stress and other finite element analysis results with the traditional bearing theory, which has guiding function for improving the design of slewing bearing.

  7. Performance of Infinitely Wide Parabolic and Inclined Slider Bearings Lubricated with Couple Stress or Magnetic Fluids

    Science.gov (United States)

    Oladeinde, Mobolaji Humphrey; Akpobi, John Ajokpaoghene

    2011-10-01

    The hydrodynamic and magnetohydrodynamic (MHD) lubrication problem of infinitely wide inclined and parabolic slider bearings is solved numerically using the finite element method. The bearing configurations are discretized into three-node isoparametric quadratic elements. Stiffness integrals obtained from the weak form of the governing equations are solved using Gauss quadrature to obtain a finite number of stiffness matrices. The global system of equations obtained from enforcing nodal continuity of pressure for the bearings are solved using the Gauss-Seidel iterative scheme with a convergence criterion of 10-10. Numerical computations reveal that, when compared for similar profile and couple stress parameters, greater pressure builds up in a parabolic slider compared to an inclined slider, indicating a greater wedge effect in the parabolic slider. The parabolic slider bearing is also shown to develop a greater load capacity when lubricated with magnetic fluids. The superior performance of parabolic slider bearing is more pronounced at greater Hartmann numbers for identical bearing structural parameters. It is also shown that when load carrying capacity is the yardstick for comparison, the parabolic slider bearings are superior to the inclined bearings when lubricated with couple stress or magnetic lubricants.

  8. Vibration model of rolling element bearings in a rotor-bearing system for fault diagnosis

    Science.gov (United States)

    Cong, Feiyun; Chen, Jin; Dong, Guangming; Pecht, Michael

    2013-04-01

    Rolling element bearing faults are among the main causes of breakdown in rotating machines. In this paper, a rolling bearing fault model is proposed based on the dynamic load analysis of a rotor-bearing system. The rotor impact factor is taken into consideration in the rolling bearing fault signal model. The defect load on the surface of the bearing is divided into two parts, the alternate load and the determinate load. The vibration response of the proposed fault signal model is investigated and the fault signal calculating equation is derived through dynamic and kinematic analysis. Outer race and inner race fault simulations are realized in the paper. The simulation process includes consideration of several parameters, such as the gravity of the rotor-bearing system, the imbalance of the rotor, and the location of the defect on the surface. The simulation results show that different amplitude contributions of the alternate load and determinate load will cause different envelope spectrum expressions. The rotating frequency sidebands will occur in the envelope spectrum in addition to the fault characteristic frequency. This appearance of sidebands will increase the difficulty of fault recognition in intelligent fault diagnosis. The experiments given in the paper have successfully verified the proposed signal model simulation results. The test rig design of the rotor bearing system simulated several operating conditions: (1) rotor bearing only; (2) rotor bearing with loader added; (3) rotor bearing with loader and rotor disk; and (4) bearing fault simulation without rotor influence. The results of the experiments have verified that the proposed rolling bearing signal model is important to the rolling bearing fault diagnosis of rotor-bearing systems.

  9. Active magnetic bearings used as exciters for rolling element bearing outer race defect diagnosis.

    Science.gov (United States)

    Xu, Yuanping; Di, Long; Zhou, Jin; Jin, Chaowu; Guo, Qintao

    2016-03-01

    The active health monitoring of rotordynamic systems in the presence of bearing outer race defect is considered in this paper. The shaft is assumed to be supported by conventional mechanical bearings and an active magnetic bearing (AMB) is used in the mid of the shaft location as an exciter to apply electromagnetic force to the system. We investigate a nonlinear bearing-pedestal system model with the outer race defect under the electromagnetic force. The nonlinear differential equations are integrated using the fourth-order Runge-Kutta algorithm. The simulation and experimental results show that the characteristic signal of outer race incipient defect is significantly amplified under the electromagnetic force through the AMBs, which is helpful to improve the diagnosis accuracy of rolling element bearing׳s incipient outer race defect. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  10. A finite element thermohydrodynamic analyis of profile bore bearing

    International Nuclear Information System (INIS)

    Shah Nor bin Basri

    1994-01-01

    A finite element-based method is presented for analysing the thermohydrodynamic (THD) behaviour of profile bore bearing. A variational statement for the governing equation is derived and used to formulate a non-linear quadrilateral finite element of serendipity family. The predicted behaviour is compared with experimental evidence where possible and favorable correlation is obtained

  11. Predicting the Remaining Useful Life of Rolling Element Bearings

    DEFF Research Database (Denmark)

    Hooghoudt, Jan Otto; Jantunen, E; Yi, Yang

    2018-01-01

    Condition monitoring of rolling element bearings is of vital importance in order to keep the industrial wheels running. In wind industry this is especially important due to the challenges in practical maintenance. The paper presents an attempt to improve the capability of prediction of remaining...

  12. Fluid-film bearings: a finite element method of analysis

    International Nuclear Information System (INIS)

    Pururav, T.; Soni, R.S.; Kushwaha, H.S.; Mahajan, S.C.

    1995-01-01

    Finite element method (FEM) has become a very popular technique for the analysis of fluid-film bearings in the last few years. These bearings are extensively used in nuclear industry applications such as in moderator pumps and main coolant pumps. This report gives the methodology for the solution of Reynold's equation using FEM and its implementation in FE software LUBAN developed in house. It also deals with the mathematical basis and algorithm to account for the cavitation phenomena which makes these problems non-linear in nature. The dynamic coefficients of bearings are evaluated by one-step approach using variational principles. These coefficients are useful for the dynamic characterisation of fluid-film bearings. Several problems have been solved using this code including two real life problems, a circumferentially grooved journal bearing for which experimental results are available and the bearing of moderator pump of 500 MWe PHWR, have been solved. The results obtained for sample problems are in good agreement with the published literature. (author). 9 refs., 14 figs., 5 tabs., 2 ills

  13. LOAD BEARING CAPACITY OF THE GLASS RAILING ELEMENT

    Directory of Open Access Journals (Sweden)

    Elizabeta Šamec

    2016-02-01

    Full Text Available In this paper some basic physical and mechanical properties of glass as structural material are presented. This research is about specifically manufactured glass railing element that will be a part of a pedestrian bridge construction in Zagreb, Croatia. Load bearing capacity test of the glass railing element is conducted within the Faculty of Civil Engineering in Zagreb and obtained experimental results are discussed and compared to the ones provided by the numerical model. Taking into account the behaviour of laminated glass and results of experimental and numerical testing, glass railing element can be regarded as safe.

  14. Nonlinear effects caused by coupling misalignment in rotors equipped with journal bearings

    Science.gov (United States)

    Pennacchi, Paolo; Vania, Andrea; Chatterton, Steven

    2012-07-01

    Misalignment is one of the most common sources of trouble of rotating machinery when rigid couplings connect the shafts. Ideal alignment of the shafts is difficult to be obtained and rotors may present angular and/or parallel misalignment (defined also as radial misalignment or offset). During a complete shaft revolution, a periodical change of the bearings load occurs in hyperstatic shaft-lines, if coupling misalignment between the shafts is excessive. If the rotating machine is equipped with fluid-film journal bearings, the change of the loads on the bearing causes also the variation of their instantaneous dynamic characteristics, i.e. damping and stiffness, and the complete system cannot be considered any longer as linear. Despite misalignment is often observed in the practice, there are relatively few studies about this phenomenon in literature and their results are sometimes conflicting. The authors aim at modeling accurately this phenomenon, for the first time in this paper, and giving pertinent diagnostic information. The proposed method is suitable for every type of shaft-line supported by journal bearings. A finite element model is used for the hyperstatic shaft-line, while bearing characteristics are calculated by integrating Reynolds equation as a function of the instantaneous load acting on the bearings, caused also by the coupling misalignment. The results obtained by applying the proposed method are shown by means of the simulation, in the time domain, of the dynamical response of a hyperstatic shaft-line. Nonlinear effects are highlighted and the spectral components of the system response are analyzed, in order to give diagnostic information about the signature of this type of fault.

  15. [Determination of a Friction Coefficient for THA Bearing Couples].

    Science.gov (United States)

    Vrbka, M; Nečas, D; Bartošík, J; Hartl, M; Křupka, I; Galandáková, A; Gallo, J

    2015-01-01

    The wear of articular surfaces is considered one of the most important factors limiting the life of total hip arthroplasty (THA). It is assumed that the particles released from the surface of a softer material induce a complex inflammatory response, which will eventually result in osteolysis and aseptic loosening. Implant wear is related to a friction coefficient which depends on combination of the materials used, roughness of the articulating surfaces, internal clearance, and dimensions of the prosthesis. The selected parameters of the bearing couples tested were studied using an experimental device based on the principle of a pendulum. Bovine serum was used as a lubricant and the load corresponded to a human body mass of 75 kg. The friction coefficient was derived from a curve of slowdown of pendulum oscillations. Roughness was measured with a device working on the principle of interferometry. Clearance was assessed by measuring diameters of the acetabular and femoral heads with a 3D optical scanner. The specimens tested included unused metal-on-highly cross-linked polyethylene, ceramic-on-highly cross-linked polyethylene and ceramic-on-ceramic bearing couples with the diameters of 28 mm and 36 mm. For each measured parameter, an arithmetic mean was calculated from 10 measurements. 1) The roughness of polyethylene surfaces was higher by about one order of magnitude than the roughness of metal and ceramic components. The Protasul metal head had the least rough surface (0.003 μm). 2) The ceramic-on-ceramic couples had the lowest clearance. Bearing couples with polyethylene acetabular liners had markedly higher clearances ranging from 150 μm to 545 μm. A clearance increased with large femoral heads (up to 4-fold in one of the couple tested). 3) The friction coefficient was related to the combination of materials; it was lowest in ceramic-on-ceramic surfaces (0.11 to 0.12) and then in ceramic-on-polyethylene implants (0.13 to 0.14). The friction coefficient is

  16. The effect of external dynamic loads on the lifetime of rolling element bearings: accurate measurement of the bearing behaviour

    International Nuclear Information System (INIS)

    Jacobs, W; Boonen, R; Sas, P; Moens, D

    2012-01-01

    Accurate prediction of the lifetime of rolling element bearings is a crucial step towards a reliable design of many rotating machines. Recent research emphasizes an important influence of external dynamic loads on the lifetime of bearings. However, most lifetime calculations of bearings are based on the classical ISO 281 standard, neglecting this influence. For bearings subjected to highly varying loads, this leads to inaccurate estimations of the lifetime, and therefore excessive safety factors during the design and unexpected failures during operation. This paper presents a novel test rig, developed to analyse the behaviour of rolling element bearings subjected to highly varying loads. Since bearings are very precise machine components, their motion can only be measured in an accurately controlled environment. Otherwise, noise from other components and external influences such as temperature variations will dominate the measurements. The test rig is optimised to perform accurate measurements of the bearing behaviour. Also, the test bearing is fitted in a modular structure, which guarantees precise mounting and allows testing different types and sizes of bearings. Finally, a fully controlled multi-axial static and dynamic load is imposed on the bearing, while its behaviour is monitored with capacitive proximity probes.

  17. Effect of Magnetohydrodynamic Couple Stresses on Dynamic Characteristics of Exponential Slider Bearing

    Directory of Open Access Journals (Sweden)

    N.B. Naduvinamani

    2017-05-01

    Full Text Available The effect of couple stresses on static and dynamic characteristics of exponential slider bearing in the presence of magnetic field considering squeeze action is theoretically analyzed in this paper. The modified magnetohydrodynamic couple stress Reynolds type equation is derived on the basis of Stokes couple stress model and closed form expressions are obtained for static and dynamic character coefficients. Comparing with bearing lubricated with non-conducting Newtonian lubricants, the magnetohydrodynamic couple stress lubrication provides the higher steady load carrying capacity, dynamic stiffness and damping coefficient. The exponential bearing shows higher efficiency for small film thickness at higher value of couple stress parameter and Hartmann number.

  18. Diagnosis of faults in rolling element bearings by using directional spectra of vibration signals

    International Nuclear Information System (INIS)

    Park, Jong Po; Lee, Chong Won

    1999-01-01

    Backward and forward defect frequencies of rolling element bearing are experimentally investigated utilizing the two-sided directional spectra of the complex-valued vibration signals measured from the outer ring of defective bearings. The experimental results show that the directional zoom spectrum is superior to the conventional spectrum in identification of bearing defect frequencies, in particular the inner race defect frequencies

  19. Intermediate coupling collision strengths from LS coupled R-matrix elements

    International Nuclear Information System (INIS)

    Clark, R.E.H.

    1978-01-01

    Fine structure collision strength for transitions between two groups of states in intermediate coupling and with inclusion of configuration mixing are obtained from LS coupled reactance matrix elements (R-matrix elements) and a set of mixing coefficients. The LS coupled R-matrix elements are transformed to pair coupling using Wigner 6-j coefficients. From these pair coupled R-matrix elements together with a set of mixing coefficients, R-matrix elements are obtained which include the intermediate coupling and configuration mixing effects. Finally, from the latter R-matrix elements, collision strengths for fine structure transitions are computed (with inclusion of both intermediate coupling and configuration mixing). (Auth.)

  20. Coupled numerical modeling of gas hydrates bearing sediments from laboratory to field-scale conditions

    Science.gov (United States)

    Sanchez, M. J.; Santamarina, C.; Gai, X., Sr.; Teymouri, M., Sr.

    2017-12-01

    Stability and behavior of Hydrate Bearing Sediments (HBS) are characterized by the metastable character of the gas hydrate structure which strongly depends on thermo-hydro-chemo-mechanical (THCM) actions. Hydrate formation, dissociation and methane production from hydrate bearing sediments are coupled THCM processes that involve, amongst other, exothermic formation and endothermic dissociation of hydrate and ice phases, mixed fluid flow and large changes in fluid pressure. The analysis of available data from past field and laboratory experiments, and the optimization of future field production studies require a formal and robust numerical framework able to capture the very complex behavior of this type of soil. A comprehensive fully coupled THCM formulation has been developed and implemented into a finite element code to tackle problems involving gas hydrates sediments. Special attention is paid to the geomechanical behavior of HBS, and particularly to their response upon hydrate dissociation under loading. The numerical framework has been validated against recent experiments conducted under controlled conditions in the laboratory that challenge the proposed approach and highlight the complex interaction among THCM processes in HBS. The performance of the models in these case studies is highly satisfactory. Finally, the numerical code is applied to analyze the behavior of gas hydrate soils under field-scale conditions exploring different features of material behavior under possible reservoir conditions.

  1. Fault diagnosis of rolling element bearing using a new optimal scale morphology analysis method.

    Science.gov (United States)

    Yan, Xiaoan; Jia, Minping; Zhang, Wan; Zhu, Lin

    2018-02-01

    Periodic transient impulses are key indicators of rolling element bearing defects. Efficient acquisition of impact impulses concerned with the defects is of much concern to the precise detection of bearing defects. However, transient features of rolling element bearing are generally immersed in stochastic noise and harmonic interference. Therefore, in this paper, a new optimal scale morphology analysis method, named adaptive multiscale combination morphological filter-hat transform (AMCMFH), is proposed for rolling element bearing fault diagnosis, which can both reduce stochastic noise and reserve signal details. In this method, firstly, an adaptive selection strategy based on the feature energy factor (FEF) is introduced to determine the optimal structuring element (SE) scale of multiscale combination morphological filter-hat transform (MCMFH). Subsequently, MCMFH containing the optimal SE scale is applied to obtain the impulse components from the bearing vibration signal. Finally, fault types of bearing are confirmed by extracting the defective frequency from envelope spectrum of the impulse components. The validity of the proposed method is verified through the simulated analysis and bearing vibration data derived from the laboratory bench. Results indicate that the proposed method has a good capability to recognize localized faults appeared on rolling element bearing from vibration signal. The study supplies a novel technique for the detection of faulty bearing. Copyright © 2018. Published by Elsevier Ltd.

  2. Investigation on laser welding characteristics for appendage of bearing pads of nuclear fuel element

    International Nuclear Information System (INIS)

    Kim, S. S.; Kim, W. K.; Park, C. H.; Ko, J. H.; Lee, J. W.; Yang, M. S.

    2001-01-01

    In CANDU nuclear fuel manufacturing the brazing technology has been adopted conventionally to attach the bearing pads of nuclear fuel elements. However, in order to meet good performance of nuclear fuel and improved working efficiency, we started developing the laser welding technology for attachments of the bearing pads. Since the YAG laser can be suitable for small parts and transmit the beam through the optical fiber, the process is corresponding to mass-production with working shops. Making the most of this feature, we have developed the laser welding for appendage of the bearing pads of nuclear fuel elements, and has studied on the laser welding characterisitcs of appendages for nuclear fuel element

  3. A Rolling Element Bearing Fault Diagnosis Approach Based on Multifractal Theory and Gray Relation Theory.

    Science.gov (United States)

    Li, Jingchao; Cao, Yunpeng; Ying, Yulong; Li, Shuying

    2016-01-01

    Bearing failure is one of the dominant causes of failure and breakdowns in rotating machinery, leading to huge economic loss. Aiming at the nonstationary and nonlinear characteristics of bearing vibration signals as well as the complexity of condition-indicating information distribution in the signals, a novel rolling element bearing fault diagnosis method based on multifractal theory and gray relation theory was proposed in the paper. Firstly, a generalized multifractal dimension algorithm was developed to extract the characteristic vectors of fault features from the bearing vibration signals, which can offer more meaningful and distinguishing information reflecting different bearing health status in comparison with conventional single fractal dimension. After feature extraction by multifractal dimensions, an adaptive gray relation algorithm was applied to implement an automated bearing fault pattern recognition. The experimental results show that the proposed method can identify various bearing fault types as well as severities effectively and accurately.

  4. Coupled vibrations in horizontal and vertical rotor-bearing systems

    OpenAIRE

    Luneno, Jean-Claude

    2011-01-01

    For dynamical systems having several degrees of freedom, motion in one direction can induce motion in the other. This means that there is a certain coupling between these two motions. Coupling can in some cases be a source of instability that causes self-excited vibrations in rotating machinery. In classical modeling of rotor systems, couplings other than those that are the result of gyroscopic effect are normally not considered. This is due to thecomplexity of the reasons for coupling which ...

  5. Dynamics Modeling and Analysis of Local Fault of Rolling Element Bearing

    Directory of Open Access Journals (Sweden)

    Lingli Cui

    2015-01-01

    Full Text Available This paper presents a nonlinear vibration model of rolling element bearings with 5 degrees of freedom based on Hertz contact theory and relevant bearing knowledge of kinematics and dynamics. The slipping of ball, oil film stiffness, and the nonlinear time-varying stiffness of the bearing are taken into consideration in the model proposed here. The single-point local fault model of rolling element bearing is introduced into the nonlinear model with 5 degrees of freedom according to the loss of the contact deformation of ball when it rolls into and out of the local fault location. The functions of spall depth corresponding to defects of different shapes are discussed separately in this paper. Then the ode solver in Matlab is adopted to perform a numerical solution on the nonlinear vibration model to simulate the vibration response of the rolling elements bearings with local fault. The simulation signals analysis results show a similar behavior and pattern to that observed in the processed experimental signals of rolling element bearings in both time domain and frequency domain which validated the nonlinear vibration model proposed here to generate typical rolling element bearings local fault signals for possible and effective fault diagnostic algorithms research.

  6. Coupled vibrations in horizontal and vertical rotor-bearings systems

    OpenAIRE

    Luneno, Jean-Claude

    2010-01-01

    For dynamical systems having several degrees of freedom, motion in one direction can induce motion in the other and/or vice versa. This means that there is a certain coupling between these two motions. Coupling can in some cases be a source of instability that causes self-excited vibrations in rotating machinery. In modeling hydropower rotors, couplings other than those that are the result of gyroscopic effect are normally not considered. This is due to the complexity of the reasons for coupl...

  7. Sparsity guided empirical wavelet transform for fault diagnosis of rolling element bearings

    Science.gov (United States)

    Wang, Dong; Zhao, Yang; Yi, Cai; Tsui, Kwok-Leung; Lin, Jianhui

    2018-02-01

    Rolling element bearings are widely used in various industrial machines, such as electric motors, generators, pumps, gearboxes, railway axles, turbines, and helicopter transmissions. Fault diagnosis of rolling element bearings is beneficial to preventing any unexpected accident and reducing economic loss. In the past years, many bearing fault detection methods have been developed. Recently, a new adaptive signal processing method called empirical wavelet transform attracts much attention from readers and engineers and its applications to bearing fault diagnosis have been reported. The main problem of empirical wavelet transform is that Fourier segments required in empirical wavelet transform are strongly dependent on the local maxima of the amplitudes of the Fourier spectrum of a signal, which connotes that Fourier segments are not always reliable and effective if the Fourier spectrum of the signal is complicated and overwhelmed by heavy noises and other strong vibration components. In this paper, sparsity guided empirical wavelet transform is proposed to automatically establish Fourier segments required in empirical wavelet transform for fault diagnosis of rolling element bearings. Industrial bearing fault signals caused by single and multiple railway axle bearing defects are used to verify the effectiveness of the proposed sparsity guided empirical wavelet transform. Results show that the proposed method can automatically discover Fourier segments required in empirical wavelet transform and reveal single and multiple railway axle bearing defects. Besides, some comparisons with three popular signal processing methods including ensemble empirical mode decomposition, the fast kurtogram and the fast spectral correlation are conducted to highlight the superiority of the proposed method.

  8. Analysis of Nanoparticle Additive Couple Stress Fluids in Three-layered Journal Bearing

    International Nuclear Information System (INIS)

    Rao, T V V L N; Sufian, S; Mohamed, N M

    2013-01-01

    The present theoretical study investigates the load capacity and friction coefficient in a three-layered journal bearing lubricated with nanoparticle additive couple stress fluids. The couple stresses effects are analyzed based on Stokes micro-continuum theory. The nondimensional pressure and shear stress expressions are derived using modified Reynolds equation. The nondimensional load capacity increases and the coefficient of friction decreases using nanoparticle additive lubricants with couple stress effects. The three-layered journal bearing performance characteristics are improved with increase in both (i) surface adsorbent fluid film layer thickness and (ii) dynamic viscosity ratio of surface to core layer.

  9. Bearing Performance Degradation Assessment Using Linear Discriminant Analysis and Coupled HMM

    International Nuclear Information System (INIS)

    Liu, T; Chen, J; Zhou, X N; Xiao, W B

    2012-01-01

    Bearing is one of the most important units in rotary machinery, its performance may vary significantly under different working stages. Thus it is critical to choose the most effective features for bearing performance degradation prediction. Linear Discriminant Analysis (LDA) is a useful method in finding few feature's dimensions that best discriminate a set of features extracted from original vibration signals. Another challenge in bearing performance degradation is how to build a model to recognize the different conditions with the data coming from different monitoring channels. In this paper, coupled hidden Markov models (CHMM) is presented to model interacting processes which can overcome the defections of the HMM. Because the input data in CHMM are collected by several sensors, and the interacting information can be fused by coupled modalities, it is more effective than HMM which used only one state chain. The model can be used in estimating the bearing performance degradation states according to several observation data. When becoming degradation pattern recognition, the new observation features should be input into the pre-trained CHMM and calculate the performance index (PI) of the outputs, the changing of PI could be used to describe the different degradation level of the bearings. The results show that PI will decline with the increase of the bearing degradation. Assessment results of the whole life time experimental bearing signals validate the feasibility and effectiveness of this method.

  10. Evaluation of Strip Footing Bearing Capacity Built on the Anthropogenic Embankment by Random Finite Element Method

    Science.gov (United States)

    Pieczynska-Kozlowska, Joanna

    2014-05-01

    One of a geotechnical problem in the area of Wroclaw is an anthropogenic embankment layer delaying to the depth of 4-5m, arising as a result of historical incidents. In such a case an assumption of bearing capacity of strip footing might be difficult. The standard solution is to use a deep foundation or foundation soil replacement. However both methods generate significant costs. In the present paper the authors focused their attention on the influence of anthropogenic embankment variability on bearing capacity. Soil parameters were defined on the basis of CPT test and modeled as 2D anisotropic random fields and the assumption of bearing capacity were made according deterministic finite element methods. Many repeated of the different realizations of random fields lead to stable expected value of bearing capacity. The algorithm used to estimate the bearing capacity of strip footing was the random finite element method (e.g. [1]). In traditional approach of bearing capacity the formula proposed by [2] is taken into account. qf = c'Nc + qNq + 0.5γBN- γ (1) where: qf is the ultimate bearing stress, cis the cohesion, qis the overburden load due to foundation embedment, γ is the soil unit weight, Bis the footing width, and Nc, Nq and Nγ are the bearing capacity factors. The method of evaluation the bearing capacity of strip footing based on finite element method incorporate five parameters: Young's modulus (E), Poisson's ratio (ν), dilation angle (ψ), cohesion (c), and friction angle (φ). In the present study E, ν and ψ are held constant while c and φ are randomized. Although the Young's modulus does not affect the bearing capacity it governs the initial elastic response of the soil. Plastic stress redistribution is accomplished using a viscoplastic algorithm merge with an elastic perfectly plastic (Mohr - Coulomb) failure criterion. In this paper a typical finite element mesh was assumed with 8-node elements consist in 50 columns and 20 rows. Footings width B

  11. Application of powder metallurgy techniques to produce improved bearing elements for liquid rocket engines

    Science.gov (United States)

    Moracz, D. J.; Shipley, R. J.; Moxson, V. S.; Killman, R. J.; Munson, H. E.

    1992-01-01

    The objective was to apply powder metallurgy techniques for the production of improved bearing elements, specifically balls and races, for advanced cryogenic turbopump bearings. The materials and fabrication techniques evaluated were judged on the basis of their ability to improve fatigue life, wear resistance, and corrosion resistance of Space Shuttle Main Engine (SSME) propellant bearings over the currently used 440C. An extensive list of candidate bearing alloys in five different categories was considered: tool/die steels, through hardened stainless steels, cobalt-base alloys, and gear steels. Testing of alloys for final consideration included hardness, rolling contact fatigue, cross cylinder wear, elevated temperature wear, room and cryogenic fracture toughness, stress corrosion cracking, and five-ball (rolling-sliding element) testing. Results of the program indicated two alloys that showed promise for improved bearing elements. These alloys were MRC-2001 and X-405. 57mm bearings were fabricated from the MRC-2001 alloy for further actual hardware rig testing by NASA-MSFC.

  12. Nonlinear dynamics of a flexible rotor supported by turbulent journal bearings with couple stress fluid

    International Nuclear Information System (INIS)

    Lo, C.-Y.; Chang-Jian, C.-W.

    2008-01-01

    This study presents a dynamic analysis of a rotor supported by two turbulent flow model journal bearings and lubricated with couple stress fluid under nonlinear suspension. The dynamics of the rotor center and bearing center is studied. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The results show that the values of dimensionless parameters l* strongly influence dynamic motions of bearing and rotor centre. It is found that couple stress fluid improve the stability of the system when l* > 0.4 even if the flow of this system is turbulent. We also demonstrated that the dimensionless rotational speed ratios s and the dimensionless unbalance parameter β are also significant system parameters. The modeling results thus obtained by using the method proposed in this paper can be employed to predict the stability of the rotor-bearing system and the undesirable behavior of the rotor and bearing center can be avoided

  13. A Signal Based Triangular Structuring Element for Mathematical Morphological Analysis and Its Application in Rolling Element Bearing Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Zhaowen Chen

    2014-01-01

    Full Text Available Mathematical morphology (MM is an efficient nonlinear signal processing tool. It can be adopted to extract fault information from bearing signal according to a structuring element (SE. Since the bearing signal features differ for every unique cause of failure, the SEs should be well tailored to extract the fault feature from a particular signal. In the following, a signal based triangular SE according to the statistics of the magnitude of a vibration signal is proposed, together with associated methodology, which processes the bearing signal by MM analysis based on proposed SE to get the morphology spectrum of a signal. A correlation analysis on morphology spectrum is then employed to obtain the final classification of bearing faults. The classification performance of the proposed method is evaluated by a set of bearing vibration signals with inner race, ball, and outer race faults, respectively. Results show that all faults can be detected clearly and correctly. Compared with a commonly used flat SE, the correlation analysis on morphology spectrum with proposed SE gives better performance at fault diagnosis of bearing, especially the identification of the location of outer race fault and the level of fault severity.

  14. A fully coupled air foil bearing model considering friction – Theory & experiment

    DEFF Research Database (Denmark)

    von Osmanski, Alexander Sebastian; Larsen, Jon Steffen; Santos, Ilmar

    2017-01-01

    The dynamics of air foil bearings (AFBs) are not yet fully captured by any model. The recent years have, however, seen promising results from nonlinear time domain models, and simultaneously coupled formulations are now available, avoiding the previous requirements for undesirably small time steps...

  15. A hybrid feature selection and health indicator construction scheme for delay-time-based degradation modelling of rolling element bearings

    Science.gov (United States)

    Zhang, Bin; Deng, Congying; Zhang, Yi

    2018-03-01

    Rolling element bearings are mechanical components used frequently in most rotating machinery and they are also vulnerable links representing the main source of failures in such systems. Thus, health condition monitoring and fault diagnosis of rolling element bearings have long been studied to improve operational reliability and maintenance efficiency of rotatory machines. Over the past decade, prognosis that enables forewarning of failure and estimation of residual life attracted increasing attention. To accurately and efficiently predict failure of the rolling element bearing, the degradation requires to be well represented and modelled. For this purpose, degradation of the rolling element bearing is analysed with the delay-time-based model in this paper. Also, a hybrid feature selection and health indicator construction scheme is proposed for extraction of the bearing health relevant information from condition monitoring sensor data. Effectiveness of the presented approach is validated through case studies on rolling element bearing run-to-failure experiments.

  16. Curvilinear steel elements in load-bearing structures of high-rise building spatial frames

    Directory of Open Access Journals (Sweden)

    Ibragimov Alexander

    2018-01-01

    Full Text Available The application of curvilinear elements in load-bearing metal structures of high-rise buildings supposes ensuring of their bearing capacity and serviceability. There may exist a great variety of shapes and orientations of such structural elements. In particular, it may be various flat curves of an open or closed oval profile such as circular or parabolic arch or ellipse. The considered approach implies creating vast internal volumes without loss in the load-bearing capacity of the frame. The basic concept makes possible a wide variety of layout and design solutions. The presence of free internal spaces of large volume in "skyscraper" type buildings contributes to resolving a great number of problems, including those of communicative nature. The calculation results confirm the basic assumptions.

  17. Curvilinear steel elements in load-bearing structures of high-rise building spatial frames

    Science.gov (United States)

    Ibragimov, Alexander; Danilov, Alexander

    2018-03-01

    The application of curvilinear elements in load-bearing metal structures of high-rise buildings supposes ensuring of their bearing capacity and serviceability. There may exist a great variety of shapes and orientations of such structural elements. In particular, it may be various flat curves of an open or closed oval profile such as circular or parabolic arch or ellipse. The considered approach implies creating vast internal volumes without loss in the load-bearing capacity of the frame. The basic concept makes possible a wide variety of layout and design solutions. The presence of free internal spaces of large volume in "skyscraper" type buildings contributes to resolving a great number of problems, including those of communicative nature. The calculation results confirm the basic assumptions.

  18. Coupled lateral-torsional-axial vibrations of a helical gear-rotor-bearing system

    Science.gov (United States)

    Li, Chao-Feng; Zhou, Shi-Hua; Liu, Jie; Wen, Bang-Chun

    2014-10-01

    Considering the axial and radial loads, a mathematical model of angular contact ball bearing is deduced with Hertz contact theory. With the coupling effects of lateral, torsional and axial vibrations taken into account, a lumped-parameter nonlinear dynamic model of helical gearrotor-bearing system (HGRBS) is established to obtain the transmission system dynamic response to the changes of different parameters. The vibration differential equations of the drive system are derived through the Lagrange equation, which considers the kinetic and potential energies, the dissipative function and the internal/external excitation. Based on the Runge-Kutta numerical method, the dynamics of the HGRBS is investigated, which describes vibration properties of HGRBS more comprehensively. The results show that the vibration amplitudes have obvious fluctuation, and the frequency multiplication and random frequency components become increasingly obvious with changing rotational speed and eccentricity at gear and bearing positions. Axial vibration of the HGRBS also has some fluctuations. The bearing has self-variable stiffness frequency, which should be avoided in engineering design. In addition, the bearing clearance needs little attention due to its slightly discernible effect on vibration response. It is suggested that a careful examination should be made in modelling the nonlinear dynamic behavior of a helical gear-rotor-bearing system.

  19. Study on Nonlinear Vibration and Crack Fault of Rotor-bearing-seal Coupling System

    Directory of Open Access Journals (Sweden)

    Yuegang LUO

    2014-02-01

    Full Text Available The nonlinear dynamic model of rotor-bearing-seal system with crack in shaft is set up based on the coupling model of nonlinear oil-film force and Muszyska’s nonlinear seal fluid force. The dynamic vibration characteristics of the rotor-bearing-seal system and the effects of physical and structural parameters of labyrinth seal and crack fault on movement character of the rotor were analyzed. The increases of seal length, seal pressure differential, seal radius and axial velocity are in favor of the stability of the system, and it of seal gap and crack depth are not in favor of the stability of the system.

  20. Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions

    Directory of Open Access Journals (Sweden)

    Lang Xue

    2017-06-01

    Full Text Available Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

  1. Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions.

    Science.gov (United States)

    Xue, Lang; Li, Naipeng; Lei, Yaguo; Li, Ningbo

    2017-06-20

    Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR) features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP) is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

  2. Coupling of smooth particle hydrodynamics with the finite element method

    International Nuclear Information System (INIS)

    Attaway, S.W.; Heinstein, M.W.; Swegle, J.W.

    1994-01-01

    A gridless technique called smooth particle hydrodynamics (SPH) has been coupled with the transient dynamics finite element code ppercase[pronto]. In this paper, a new weighted residual derivation for the SPH method will be presented, and the methods used to embed SPH within ppercase[pronto] will be outlined. Example SPH ppercase[pronto] calculations will also be presented. One major difficulty associated with the Lagrangian finite element method is modeling materials with no shear strength; for example, gases, fluids and explosive biproducts. Typically, these materials can be modeled for only a short time with a Lagrangian finite element code. Large distortions cause tangling of the mesh, which will eventually lead to numerical difficulties, such as negative element area or ''bow tie'' elements. Remeshing will allow the problem to continue for a short while, but the large distortions can prevent a complete analysis. SPH is a gridless Lagrangian technique. Requiring no mesh, SPH has the potential to model material fracture, large shear flows and penetration. SPH computes the strain rate and the stress divergence based on the nearest neighbors of a particle, which are determined using an efficient particle-sorting technique. Embedding the SPH method within ppercase[pronto] allows part of the problem to be modeled with quadrilateral finite elements, while other parts are modeled with the gridless SPH method. SPH elements are coupled to the quadrilateral elements through a contact-like algorithm. ((orig.))

  3. Bearing system

    Science.gov (United States)

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  4. Rolling element bearings diagnostics using the Symbolic Aggregate approXimation

    Science.gov (United States)

    Georgoulas, George; Karvelis, Petros; Loutas, Theodoros; Stylios, Chrysostomos D.

    2015-08-01

    Rolling element bearings are a very critical component in various engineering assets. Therefore it is of paramount importance the detection of possible faults, especially at an early stage, that may lead to unexpected interruptions of the production or worse, to severe accidents. This research work introduces a novel, in the field of bearing fault detection, method for the extraction of diagnostic representations of vibration recordings using the Symbolic Aggregate approXimation (SAX) framework and the related intelligent icons representation. SAX essentially transforms the original real valued time-series into a discrete one, which is then represented by a simple histogram form summarizing the occurrence of the chosen symbols/words. Vibration signals from healthy bearings and bearings with three different fault locations and with three different severity levels, as well as loading conditions, are analyzed. Considering the diagnostic problem as a classification one, the analyzed vibration signals and the resulting feature vectors feed simple classifiers achieving remarkably high classification accuracies. Moreover a sliding window scheme combined with a simple majority voting filter further increases the reliability and robustness of the diagnostic method. The results encourage the potential use of the proposed methodology for the diagnosis of bearing faults.

  5. A 3D finite element-based model order reduction method for parametric resonance and whirling analysis of anisotropic rotor-bearing systems

    Science.gov (United States)

    Wang, Shuai; Wang, Yu; Zi, Yanyang; He, Zhengjia

    2015-12-01

    A generalized and efficient model for rotating anisotropic rotor-bearing systems is presented in this paper with full considerations of the system's anisotropy in stiffness, inertia and damping. Based on the 3D finite element model and the model order reduction method, the effects of anisotropy in shaft and bearings on the forced response and whirling of anisotropic rotor-bearing systems are systematically investigated. First, the coefficients of journal bearings are transformed from the fixed frame to the rotating one. Due to the anisotropy in shaft and bearings, the motion is governed by differential equations with periodically time-variant coefficients. Then, a free-interface complex component mode synthesis (CMS) method is employed to generate efficient reduced-order models (ROM) for the periodically time-variant systems. In order to solve the obtained equations, a variant of Hill's method for systems with multiple harmonic excitations is developed. Four dimensionless parameters are defined to quantify the types and levels of anisotropy of bearings. Finally, the effects of the four types of anisotropy on the forced response and whirl orbits are studied. Numerical results show that the anisotropy of bearings in stiffness splits the sole resonant peak into two isolated ones, but the anisotropy of bearings in damping coefficients mainly affect the response amplitudes. Moreover, the whirl orbits become much more complex when the shaft and bearings are both anisotropic. In addition, the cross-coupling stiffness coefficients of bearings significantly affect the dynamic behaviors of the systems and cannot be neglected, though they are often much smaller than the principle stiffness terms.

  6. Sequential dynamics in the motif of excitatory coupled elements

    Science.gov (United States)

    Korotkov, Alexander G.; Kazakov, Alexey O.; Osipov, Grigory V.

    2015-11-01

    In this article a new model of motif (small ensemble) of neuron-like elements is proposed. It is built with the use of the generalized Lotka-Volterra model with excitatory couplings. The main motivation for this work comes from the problems of neuroscience where excitatory couplings are proved to be the predominant type of interaction between neurons of the brain. In this paper it is shown that there are two modes depending on the type of coupling between the elements: the mode with a stable heteroclinic cycle and the mode with a stable limit cycle. Our second goal is to examine the chaotic dynamics of the generalized three-dimensional Lotka-Volterra model.

  7. Failure Diagnosis and Prognosis of Rolling - Element Bearings using Artificial Neural Networks: A Critical Overview

    Science.gov (United States)

    Rao, B. K. N.; Srinivasa Pai, P.; Nagabhushana, T. N.

    2012-05-01

    Rolling - Element Bearings are extensively used in almost all global industries. Any critical failures in these vitally important components would not only affect the overall systems performance but also its reliability, safety, availability and cost-effectiveness. Proactive strategies do exist to minimise impending failures in real time and at a minimum cost. Continuous innovative developments are taking place in the field of Artificial Neural Networks (ANNs) technology. Significant research and development are taking place in many universities, private and public organizations and a wealth of published literature is available highlighting the potential benefits of employing ANNs in intelligently monitoring, diagnosing, prognosing and managing rolling-element bearing failures. This paper attempts to critically review the recent trends in this topical area of interest.

  8. Failure Diagnosis and Prognosis of Rolling - Element Bearings using Artificial Neural Networks: A Critical Overview

    International Nuclear Information System (INIS)

    Rao, B K N; Pai, P Srinivasa; Nagabhushana, T N

    2012-01-01

    Rolling - Element Bearings are extensively used in almost all global industries. Any critical failures in these vitally important components would not only affect the overall systems performance but also its reliability, safety, availability and cost-effectiveness. Proactive strategies do exist to minimise impending failures in real time and at a minimum cost. Continuous innovative developments are taking place in the field of Artificial Neural Networks (ANNs) technology. Significant research and development are taking place in many universities, private and public organizations and a wealth of published literature is available highlighting the potential benefits of employing ANNs in intelligently monitoring, diagnosing, prognosing and managing rolling-element bearing failures. This paper attempts to critically review the recent trends in this topical area of interest.

  9. Vibration Propagation of Gear Dynamics in a Gear-Bearing-Housing System Using Mathematical Modeling and Finite Element Analysis

    Science.gov (United States)

    Parker, Robert G.; Guo, Yi; Eritenel, Tugan; Ericson, Tristan M.

    2012-01-01

    Vibration and noise caused by gear dynamics at the meshing teeth propagate through power transmission components to the surrounding environment. This study is devoted to developing computational tools to investigate the vibro-acoustic propagation of gear dynamics through a gearbox using different bearings. Detailed finite element/contact mechanics and boundary element models of the gear/bearing/housing system are established to compute the system vibration and noise propagation. Both vibration and acoustic models are validated by experiments including the vibration modal testing and sound field measurements. The effectiveness of each bearing type to disrupt vibration propagation is speed-dependent. Housing plays an important role in noise radiation .It, however, has limited effects on gear dynamics. Bearings are critical components in drivetrains. Accurate modeling of rolling element bearings is essential to assess vibration and noise of drivetrain systems. This study also seeks to fully describe the vibro-acoustic propagation of gear dynamics through a power-transmission system using rolling element and fluid film wave bearings. Fluid film wave bearings, which have higher damping than rolling element bearings, could offer an energy dissipation mechanism that reduces the gearbox noise. The effectiveness of each bearing type to disrupt vibration propagation in explored using multi-body computational models. These models include gears, shafts, rolling element and fluid film wave bearings, and the housing. Radiated noise is mapped from the gearbox surface to surrounding environment. The effectiveness of rolling element and fluid film wave bearings in breaking the vibro-acoustic propagation path from the gear to the housing is investigated.

  10. ELEMENT DESIGN FOR AN INKJET SYSTEM OF HYDROSTATIC GAS BEARING CONTROL

    Directory of Open Access Journals (Sweden)

    T. E. Il'ina

    2015-09-01

    Full Text Available Subject of Study. The paper discusses the concept of inkjet systems application, also known as pneumonics, for automatic hydrostatic gas bearing control. Inkjet systems have the advantages over traditional control systems in those problems where the speed of traditional mechanical, electrical or hydraulic servomotors is not enough. Control of the shaft position in gas bearing with forced gas supply into the gap between the shaft and the bearing is typical for this class of problems. In this case, control means the pressure changing or flow rate of gas supplied to the gap by at least one of three axes at a frequency higher than the nominal speed of the shaft. Thus, high speed of response is required from the system. The objective of this work is to design a discrete jet element, testing of its geometry and switching characteristics. Main Results. The discrete inkjet element for oil-free non-contact transmission working on the refrigerant was designed. Relay transition process was modeled in the inkjet element with the use of numerical methods. The switching time has reached 0.2-0.3 ms; this is one order less than the requirements of aircraft control systems, which typically operate at a frequency of about 200 Hz. It is shown that periodic oscillations with high frequency occur when the control signal is injected with insufficient level of pressure. Therefore, a separate design task is to determine the minimum pressure allowable in the control channel.

  11. Evaluation of Bearing Capacity of Strip Foundation Subjected to Eccentric Inclined Loads Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Ahmed Majeed Ali

    2016-08-01

    Full Text Available In real conditions of structures, foundations like retaining walls, industrial machines and platforms in offshore areas are commonly subjected to eccentrically inclined loads. This type of loading significantly affects the overall stability of shallow foundations due to exposing the foundation into two components of loads (horizontal and vertical and consequently reduces the bearing capacity Based on a numerical analysis performed using finite element software (Plaxis 3D Foundation, the behavior of model strip foundation rested on dry sand under the effect of eccentric inclined loads with different embedment ratios (D/B ranging from (0-1 has been explored. The results display that, the bearing capacity of strip foundation is noticeably decreased with the increase of inclination angle (α and eccentricity ratio (e/B. As well as, a reduction factor (RF expression was appointed to measure the degree of decreasing in the bearing capacity when the model footing is subjected to eccentric inclined load. It was observed that, the (RF decreases as the embedment ratio increases. Moreover, the test results also exhibit that, the model footing bearing capacity is reduced by about (69% when the load inclination is varied from (0° to 20° and the model footing is on the surface. While, the rate of decreasing in the bearing capacity was found to be (58%, for both cases of footing when they are at embedment ratios of (0.5 and 1.0. Also, a comparative study was carried out between the present results and previous experimental test results under the same conditions (soil properties and boundary condition. A good agreement was obtained between the predicted bearing capacities for the two related studies.

  12. Application of an improved maximum correlated kurtosis deconvolution method for fault diagnosis of rolling element bearings

    Science.gov (United States)

    Miao, Yonghao; Zhao, Ming; Lin, Jing; Lei, Yaguo

    2017-08-01

    The extraction of periodic impulses, which are the important indicators of rolling bearing faults, from vibration signals is considerably significance for fault diagnosis. Maximum correlated kurtosis deconvolution (MCKD) developed from minimum entropy deconvolution (MED) has been proven as an efficient tool for enhancing the periodic impulses in the diagnosis of rolling element bearings and gearboxes. However, challenges still exist when MCKD is applied to the bearings operating under harsh working conditions. The difficulties mainly come from the rigorous requires for the multi-input parameters and the complicated resampling process. To overcome these limitations, an improved MCKD (IMCKD) is presented in this paper. The new method estimates the iterative period by calculating the autocorrelation of the envelope signal rather than relies on the provided prior period. Moreover, the iterative period will gradually approach to the true fault period through updating the iterative period after every iterative step. Since IMCKD is unaffected by the impulse signals with the high kurtosis value, the new method selects the maximum kurtosis filtered signal as the final choice from all candidates in the assigned iterative counts. Compared with MCKD, IMCKD has three advantages. First, without considering prior period and the choice of the order of shift, IMCKD is more efficient and has higher robustness. Second, the resampling process is not necessary for IMCKD, which is greatly convenient for the subsequent frequency spectrum analysis and envelope spectrum analysis without resetting the sampling rate. Third, IMCKD has a significant performance advantage in diagnosing the bearing compound-fault which expands the application range. Finally, the effectiveness and superiority of IMCKD are validated by a number of simulated bearing fault signals and applying to compound faults and single fault diagnosis of a locomotive bearing.

  13. Geometric coupling effects on the bifurcations of a flexible rotor response in active magnetic bearings

    International Nuclear Information System (INIS)

    Inayat-Hussain, Jawaid I.

    2009-01-01

    This work reports on a numerical investigation on the bifurcations of a flexible rotor response in active magnetic bearings taking into account the nonlinearity due to the geometric coupling of the magnetic actuators as well as that arising from the actuator forces that are nonlinear function of the coil current and the air gap. For the values of design and operating parameters of the rotor-bearing system investigated in this work, numerical results showed that the response of the rotor was always synchronous when the values of the geometric coupling parameter α were small. For relatively larger values of α, however, the response of the rotor displayed a rich variety of nonlinear dynamical phenomena including sub-synchronous vibrations of periods-2, -3, -6, -9, and -17, quasi-periodicity and chaos. Numerical results further revealed the co-existence of multiple attractors within certain ranges of the speed parameter Ω. In practical rotating machinery supported by active magnetic bearings, the possibility of synchronous rotor response to become non-synchronous or even chaotic cannot be ignored as preloads, fluid forces or other external excitation forces may cause the rotor's initial conditions to move from one basin of attraction to another. Non-synchronous and chaotic vibrations should be avoided as they induce fluctuating stresses that may lead to premature failure of the machinery's main components.

  14. Compression and shear properties of elastomeric bearing using finite element analysis

    Directory of Open Access Journals (Sweden)

    2Faculty of Science and Technology, Chiang Mai Rajabhat University, Muang, Chiang Mai, 50300 Thailand.

    2006-09-01

    Full Text Available Standard size samples of four natural rubber compounds, varying the amount of carbon black from 10 to 70 phr, were characterised under uniaxial compression and simple shear tests in order to obtain the strain energy function constants. These constants were then used as hyperelastic material constants for the Windows-based finite element package (COSMOS/M version 1.75. The investigated bearings, made with those NR compounds, had the approximate area and thickness of 50x106 mm2 and 50 mm respectively. Each compound of bearing consisted of four different values of shape factor ranging from about 0.33 to 1.70, according to the number of reinforcing plates in the bearing. Three deformation modes of compression, shear and compression-shear were predicted. Good agreement was found between twelve compression model predictions and the corresponding experimental values of bearings, containing 10, 20 and 40 phr of carbon black and each of which consisted of four different layers of reinforcing metal plates (0, 1, 2 and 3 layers. On the other hand, deviation from the predicted valve was clearly seen in the 70 phr black bearing case. The percentage difference increased with respect to the increasing number of reinforcing plates or the rising shape factor. Therefore, the improved FEA model was supplemented with an imaginary elastic glue layer between the rubber block and metal plate as glue failure compensation. The optimum value of the elastic layers modulus is 8 MPa while the thickness of the layer depends on the total thickness or total volume of rubber block. This model can predict the 70 phr carbon black bearings, having shape factor ranging from 0.5 to 2.35 for 11 cases. The FEA prediction of shear behaviour agrees well with the experimental data for all four bearing compounds and there is no effect of shape factor on shear stress. Moreover, shear stress does not depend on the compressive force applied to like bearing before shear and the FEA results

  15. Fuel-element vibration and bearing pad to pressure tube fretting

    International Nuclear Information System (INIS)

    Fisher, N.J.; Taylor, C.E.; Pettigrew, M.J.

    1990-08-01

    Fuel channel operation under boiling condition results in increased flow velocities, which may lead to unacceptable fuel-element vibration and bearing pad to pressure tube fretting. The existing endurance test database does not fully cover the range of future channel operating conditions. In particular, after refuelling, some channels for future designs may operate with two-phase flow conditions outside the range of endurance test conditions. Full-scale endurance testing at realistic steam-water conditions involves substantial energy costs. Therefore, fundamental laboratory investigations were conducted to define and endurance test matrix which adequately envelops the future range of operating conditions while minimizing both the number of tests and the energy requirement of individual tests. The main focus of the laboratory investigations was to establish the relationships between: fuel channel flow conditions and fuel-element vibration; and fuel-element vibration and bearing pad to pressure tube fretting. The vibration response of a single fuel element was measured over a wide range of operating conditions covering realistic fuel channel conditions and simulated endurance testing conditions. For higher void fractions, the vibration amplitudes measured in air/water were much higher than in steam/water, while for low void fractions, the amplitudes were similar. The measured amplitudes in steam/water varied very little over the range of temperature and pressure investigated. The effects of temperature, pressure tube oxide thickness, vibration amplitude and bearing pad manufacturer on pressure tube fretting were investigated. The fretting rate is extremely temperature dependent. For vibration amplitudes about three or four times greater than expected in-reactor conditions, peak fretting rates were observed in the 225 to 286 degrees C temperature range. Fretting rates were seven times less at the higher temperatures of 300 and 315 degrees C, and the lower temperatures

  16. Multilayer Finite-Element Model Application to Define the Bearing Structure Element Stress State of Launch Complexes

    Directory of Open Access Journals (Sweden)

    V. A. Zverev

    2016-01-01

    Full Text Available The article objective is to justify the rationale for selecting the multilayer finite element model parameters of the bearing structure of a general-purpose launch complex unit.A typical design element of the launch complex unit, i.e. a mount of the hydraulic or pneumatic cylinder, block, etc. is under consideration. The mount represents a set of the cantilevered axis and external structural cage. The most loaded element of the cage is disk to which a moment is transferred from the cantilevered axis due to actuator effort acting on it.To calculate the stress-strain state of disk was used a finite element method. Five models of disk mount were created. The only difference in models was the number of layers of the finite elements through the thickness of disk. There were models, which had one, three, five, eight, and fourteen layers of finite elements through the thickness of disk. For each model, we calculated the equivalent stresses arising from the action of the test load. Disk models were formed and calculated using the MSC Nastran complex software.The article presents results in the table to show data of equivalent stresses in each of the multi-layered models and graphically to illustrate the changing equivalent stresses through the thickness of disk.Based on these results we have given advice on selecting the proper number of layers in the model allowing a desirable accuracy of results with the lowest run time. In addition, it is concluded that there is a need to use the multi-layer models in assessing the performance of structural elements in case the stress exceeds the allowable one in their surface layers.

  17. Bearing support for receiving used fuel elements of nuclear power stations

    International Nuclear Information System (INIS)

    Krieger, F.

    1979-01-01

    A bearing support for receiving used fuel elements of nuclear power stations includes a plurality of chambers which have square cross-sections and each include inner and outer spaced apart walls with screening plates therebetween for screening the radiating fuel elements. Each chamber is detachably secured at its underside to a common foot plate and is held in position at its upper side by spacer elements. The outer wall comprises two equal-sided angle sheets and the inner wall comprises a closed square tube. The thickness of the outer wall is smaller than that of the inner wall and the outer walls are held in spaced relationship to each other at their upper sides by detachable bar grates

  18. The excretion of biotrace elements using the multitracer technique in tumour-bearing mice.

    Science.gov (United States)

    Wang, X; Tian, J; Yin, X M; Zhang, X; Wang, Q Z

    2000-12-01

    A radioactive multitracer solution obtained from the nuclear reaction of selenium with 25 MeV/nucleon 40Ar ions was used for investigation of trace element excretion into the faeces and urine of cancerous mice. The excretion rates of 22 elements (Na, K, Rb, Mg, Ca, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Y, Zr, Mo, Nb, Tc, Ru, Ag and In) were simultaneously measured under strictly identical experimental conditions, in order to clarify the excretion behavior of these elements in cancerous mice. The faecal and urinary excretion rates of Mg, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Y, Zr, Nb, Ru and Mo in cancerous mice, showed the in highest value at 0-8 hours. The accumulative excretion of Ca, Mo, Y and Zr was decreased and Na, Fe, Mn and Co increased in tumour-bearing mice, when compared to normal mice.

  19. The excretion of biotrace elements using the multitracer technique in tumour-bearing mice

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Tian, J. E-mail: tianjun@public.lz.gs.cn; Yin, X.M.; Zhang, X.; Wang, Q.Z

    2000-12-15

    A radioactive multitracer solution obtained from the nuclear reaction of selenium with 25 MeV/nucleon {sup 40}Ar ions was used for investigation of trace element excretion into the faeces and urine of cancerous mice. The excretion rates of 22 elements (Na, K, Rb, Mg, Ca, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Y, Zr, Mo, Nb, Tc, Ru, Ag and In) were simultaneously measured under strictly identical experimental conditions, in order to clarify the excretion behavior of these elements in cancerous mice. The faecal and urinary excretion rates of Mg, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Y, Zr, Nb, Ru and Mo in cancerous mice, showed the in highest value at 0-8 hours. The accumulative excretion of Ca, Mo, Y and Zr was decreased and Na, Fe, Mn and Co increased in tumour-bearing mice, when compared to normal mice.

  20. The excretion of biotrace elements using the multitracer technique in tumour-bearing mice

    International Nuclear Information System (INIS)

    Wang, X.; Tian, J.; Yin, X.M.; Zhang, X.; Wang, Q.Z.

    2000-01-01

    A radioactive multitracer solution obtained from the nuclear reaction of selenium with 25 MeV/nucleon 40 Ar ions was used for investigation of trace element excretion into the faeces and urine of cancerous mice. The excretion rates of 22 elements (Na, K, Rb, Mg, Ca, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Y, Zr, Mo, Nb, Tc, Ru, Ag and In) were simultaneously measured under strictly identical experimental conditions, in order to clarify the excretion behavior of these elements in cancerous mice. The faecal and urinary excretion rates of Mg, Sr, Ga, As, Sc, V, Cr, Mn, Co, Fe, Y, Zr, Nb, Ru and Mo in cancerous mice, showed the in highest value at 0-8 hours. The accumulative excretion of Ca, Mo, Y and Zr was decreased and Na, Fe, Mn and Co increased in tumour-bearing mice, when compared to normal mice

  1. X-ray fluorescence spectroscopy for the elemental analysis of plutonium-bearing materials for the materials disposition program

    International Nuclear Information System (INIS)

    Voit, S.L.; Boerigter, S.T.; Rising, T.L.

    1997-01-01

    The US Fissile Materials Disposition (MD) program will disposition about 50 MT of plutonium in the next century. Both of the alternative technologies for disposition, MOX Fuel and Immobilization require knowledge of the incoming composition to 1--5 wt%. Wavelength Dispersive X-Ray Fluorescence (WDXRF) systems, a common elemental analysis technology with a variety of industrial applications and commercial vendors, can readily achieve this level of characterization. Since much of the excess plutonium will be packaged in a long-term storage container as part of the DOE Environmental Management (DOE-EM) program to stabilize plutonium-bearing materials, the characterization system must be implemented during the packaging process. The authors describe a preliminary design for the integration of the WDXRF system into the packaging system to be used at the Rocky Flats site. The Plutonium Stabilization and Packaging System (PuSPS), coupled with the WDXRF characterization system will provide MD with stabilized plutonium-bearing excess material that can be more readily fed to an immobilization facility. The overall added expense to the MD program of obtaining analytical information after materials have been packaged in long-term storage containers could far exceed the expense of implementing XRF analysis during the packaging process

  2. The Autogram: An effective approach for selecting the optimal demodulation band in rolling element bearings diagnosis

    Science.gov (United States)

    Moshrefzadeh, Ali; Fasana, Alessandro

    2018-05-01

    Envelope analysis is one of the most advantageous methods for rolling element bearing diagnostics but finding a suitable frequency band for demodulation has been a substantial challenge for a long time. Introduction of the Spectral Kurtosis (SK) and Kurtogram mostly solved this problem but in situations where signal to noise ratio is very low or in presence of non-Gaussian noise these methods will fail. This major drawback may noticeably decrease their effectiveness and goal of this paper is to overcome this problem. Vibration signals from rolling element bearings exhibit high levels of second-order cyclostationarity, especially in the presence of localized faults. The autocovariance function of a 2nd order cyclostationary signal is periodic and the proposed method, named Autogram, takes advantage of this property to enhance the conventional Kurtogram. The method computes the kurtosis of the unbiased Autocorrelation (AC) of the squared envelope of the demodulated signal, rather than the kurtosis of the filtered time signal. Moreover, to take advantage of unique features of the lower and upper portions of the AC, two modified forms of kurtosis are introduced and the resulting colormaps are called Upper and Lower Autogram. In addition, a thresholding method is also proposed to enhance the quality of the frequency spectrum analysis. A new indicator, Combined Squared Envelope Spectrum, is employed to consider all the frequency bands with valuable diagnostic information and to improve the fault detectability of the Autogram. The proposed method is tested on experimental data and compared with literature results so to assess its performances in rolling element bearing diagnostics.

  3. Coupling nonlinear Stokes and Darcy flow using mortar finite elements

    KAUST Repository

    Ervin, Vincent J.

    2011-11-01

    We study a system composed of a nonlinear Stokes flow in one subdomain coupled with a nonlinear porous medium flow in another subdomain. Special attention is paid to the mathematical consequence of the shear-dependent fluid viscosity for the Stokes flow and the velocity-dependent effective viscosity for the Darcy flow. Motivated by the physical setting, we consider the case where only flow rates are specified on the inflow and outflow boundaries in both subdomains. We recast the coupled Stokes-Darcy system as a reduced matching problem on the interface using a mortar space approach. We prove a number of properties of the nonlinear interface operator associated with the reduced problem, which directly yield the existence, uniqueness and regularity of a variational solution to the system. We further propose and analyze a numerical algorithm based on mortar finite elements for the interface problem and conforming finite elements for the subdomain problems. Optimal a priori error estimates are established for the interface and subdomain problems, and a number of compatibility conditions for the finite element spaces used are discussed. Numerical simulations are presented to illustrate the algorithm and to compare two treatments of the defective boundary conditions. © 2010 Published by Elsevier B.V. on behalf of IMACS.

  4. Analysis of bearing stiffness variations, contact forces and vibrations in radially loaded double row rolling element bearings with raceway defects

    Science.gov (United States)

    Petersen, Dick; Howard, Carl; Sawalhi, Nader; Moazen Ahmadi, Alireza; Singh, Sarabjeet

    2015-01-01

    A method is presented for calculating and analyzing the quasi-static load distribution and varying stiffness of a radially loaded double row bearing with a raceway defect of varying depth, length, and surface roughness. The method is applied to ball bearings on gearbox and fan test rigs seeded with line or extended outer raceway defects. When balls pass through the defect and lose all or part of their load carrying capacity, the load is redistributed between the loaded balls. This includes balls positioned outside the defect such that good raceway sections are subjected to increased loading when a defect is present. The defective bearing stiffness varies periodically at the ball spacing, and only differs from the good bearing case when balls are positioned in the defect. In this instance, the stiffness decreases in the loaded direction and increases in the unloaded direction. For an extended spall, which always has one or more balls positioned in the defect, this results in an average stiffness over the ball spacing period that is lower in the loaded direction in comparison to both the line spall and good bearing cases. The variation in bearing stiffness due to the defect produces parametric excitations of the bearing assembly. The qualitative character of the vibration response correlates to the character of the stiffness variations. Rapid stiffness changes at a defect exit produce impulses. Slower stiffness variations due to large wavelength waviness features in an extended spall produce low frequency excitation which results in defect components in the velocity spectra. The contact forces fluctuate around the quasi-static loads on the balls, with rapid stiffness changes producing high magnitude impulsive force fluctuations. Furthermore, it is shown that analyzing the properties of the dynamic model linearized at the quasi-static solutions provides greater insight into the time-frequency characteristics of the vibration response. This is demonstrated by relating

  5. Zircaloy-sheathed element rods fitted with thermo-couples

    International Nuclear Information System (INIS)

    Bernardy de Sigoyer, B.; Jacques, F.; Thome, P.

    1963-01-01

    In order to carry out thermal conductivity measurements on UO 2 in conditions similar to those under which fuel rods are used, it was necessary to measure the temperature at the interior of a fuel element sheathed in zircaloy. The temperatures are taken with Thermocoax type thermocouples, that is to say fitted with a very thin sheath of stainless steel or Inconel. It is known also that fusion welding of zircaloy onto stainless steel is impossible and that high temperature welded joints are very difficult because of their aggressiveness. The technique used consists in brazing the thermocouples to relatively large stainless steel parts and then joining these plugs by electron bombardment welding to diffused stainless steel-zircaloy couplings. The properties of these diffused couplings and of the brazed joints were studied; the various stages in the fabrication of the containers are also described. (authors) [fr

  6. The possibility of modifying the elements of the bearing assembly with nanoparticles in order to reduce the friction coefficient

    Science.gov (United States)

    Stankevich, P.; Mironovs, V.; Vasilyeva, E.; Breki, A.; Tolochko, O.

    2017-10-01

    Recent study considers the tribological characteristics of the sintered bushings used in the connecting nodes brake lever system of railway cars. Particular attention is paid sleeves low content of alloying elements. Bushings had been prepared by powder metallurgy route by using low alloyed powders of Fe-Cu-C system. Porosity after sintering was about 20%. Generally, before using material was impregnated by industrial mineral oil in order to improve friction condition. In the recent study we use new lubricating compositions for impregnating in sintered bodies. Such compositions consist of basic mineral oil with addition of 4 wt.% of layered tungsten dichalcogenides (WS2 and WSe2) nanoparticles, which were ultrasonically dispersed. Tungsten disulphide nanoparticles have spherical shape with the diameter of 30-50 nm, and diselenide nanoparticles have a flat shape with the mean dimensions of 5x70 nm. Tribological testing of the product was provided. Sintered bushings impregnated with commercial oil and suspension of nanoparticles were tested in the spinning friction conditions in the couple with bearing steel at the load of 210 N and spinning rate of 200 rpm. The friction test in couple with steel exhibited the value of friction moment to be about 2 times less as compared with commercial oil. The additions of tungsten disulphide nanoparticles also significantly decrease oscillations the friction torque.

  7. Use of the iterative solution method for coupled finite element and boundary element modeling

    International Nuclear Information System (INIS)

    Koteras, J.R.

    1993-07-01

    Tunnels buried deep within the earth constitute an important class geomechanics problems. Two numerical techniques used for the analysis of geomechanics problems, the finite element method and the boundary element method, have complementary characteristics for applications to problems of this type. The usefulness of combining these two methods for use as a geomechanics analysis tool has been recognized for some time, and a number of coupling techniques have been proposed. However, not all of them lend themselves to efficient computational implementations for large-scale problems. This report examines a coupling technique that can form the basis for an efficient analysis tool for large scale geomechanics problems through the use of an iterative equation solver

  8. Pump Coupling & Motor bearing damage detection using Condition Monitoring at DTPS

    Science.gov (United States)

    Bari, H. M.; Deshpande, A. A.; Jalkote, P. S.; Patil, S. S.

    2012-05-01

    This paper shares a success story out of the implementation of Co-ordinated Condition Monitoring techniques at DTPS, wherein imminent Mis-alignment of HT auxiliary BFP - 1B and Motor bearing failure of ID FAN - 1B was diagnosed. On 30/12/2010, Booster Pump DE horizontal reading increased from 4.8 to 5.1 and then upto 5.9 mm/sec. It was suspected that Booster pump was mis-aligned with Motor. To confirm misalignment, Phase Analysis was also done which showed that Coupling phase difference was 180 Degrees. Vibration & Phase Analysis helped in diagnosing the exact root cause of abnormity in advance, saving plant from huge losses which could have caused total cost of £ 104,071. On 06/01/2011, ID fan 1B Motor NDE & DE horizontal vibration readings deviated from 0.5 to 0.8 and 0.6 to 0.8 mm/sec (RMS) respectively. Noise level increased from 99.1 to 101.9 db. It was suspected that Motor bearings had loosened over the shaft. Meanwhile, after opening of Motor, Inner race of NDE side was found cracked and loosened over the shaft. Vibration Analysis & Noise Monitoring helped in diagnosing the exact root cause of abnormity in advance, saving plant from huge losses which could have caused total cost of £ 308,857.

  9. Micro-focus x-ray inspection of the bearing pad welded by laser for CANDU fuel element

    International Nuclear Information System (INIS)

    Kim, W. K.; Kim, S. S.; Lee, J. W.; Yang, M. S.

    2001-01-01

    To attach the bearing pads on the surface of CANDU fuel element, laser welding technique has been reviewed to replace brazing technology which is complicate process and makes use of the toxic beryllium. In this study, to evaluate the soundness of the weld of the bearing pad of CANDU fuel element, a precise X-ray inspection system was developed using a micro-focus X-ray generator with an image intensifier and a real time camera system. The weld of the bearing pad welded by Nd:YAG laser has been inspected by the developed inspection system. Image processing technique has been applied to reduce random noise and to enhance the contrast of the X-ray image. A few defects on the weld of the bearing pads have been detected by the X-ray inspection process

  10. Finite Element Analysis of the Effect on Edge Distance of the Tensile Bearing Capacity of Embedded Hanging Parts

    Directory of Open Access Journals (Sweden)

    Meng Xian Hong

    2016-01-01

    Full Text Available In order to explore the trend of tensile bearing capacity of embedded hanging parts when change the edge distance. Based on the finite element analysis software ABAQUS, the four simulation model was established. The buried depth and strength of concrete remain unchanged, but the edge distance was gradient change. By the load - displacement curve of every model known, the greater the edge distance, the greater the bearing capacity. When the edge distance reaches 1.5 times buried depth, the effect of increasing edge distance for improving the bearing capacity will be impaired.

  11. Influence of carbon and lipid sources on variation of mercury and other trace elements in polar bears (Ursus maritimus).

    Science.gov (United States)

    Routti, Heli; Letcher, Robert J; Born, Erik W; Branigan, Marsha; Dietz, Rune; Evans, Thomas J; McKinney, Melissa A; Peacock, Elizabeth; Sonne, Christian

    2012-12-01

    In the present study, the authors investigated the influence of carbon and lipid sources on regional differences in liver trace element (As, Cd, Cu, total Hg, Mn, Pb, Rb, Se, and Zn) concentrations measured in polar bears (Ursus maritimus) (n = 121) from 10 Alaskan, Canadian Arctic, and East Greenland subpopulations. Carbon and lipid sources were assessed using δ(13) C in muscle tissue and fatty acid (FA) profiles in subcutaneous adipose tissue as chemical tracers. A negative relationship between total Hg and δ(13) C suggested that polar bears feeding in areas with higher riverine inputs of terrestrial carbon accumulate more Hg than bears feeding in areas with lower freshwater input. Mercury concentrations were also positively related to the FA 20:1n-9, which is biosynthesized in large amounts in Calanus copepods. This result raises the hypothesis that Calanus glacialis are an important link in the uptake of Hg in the marine food web and ultimately in polar bears. Unadjusted total Hg, Se, and As concentrations showed greater geographical variation among polar bear subpopulations compared with concentrations adjusted for carbon and lipid sources. The Hg concentrations adjusted for carbon and lipid sources in Bering-Chukchi Sea polar bear liver tissue remained the lowest among subpopulations. Based on these findings, the authors suggest that carbon and lipid sources for polar bears should be taken into account when one is assessing spatial and temporal trends of long-range transported trace elements. Copyright © 2012 SETAC.

  12. A new methodology for fault detection in rolling element bearings using singular spectrum analysis

    Directory of Open Access Journals (Sweden)

    Bugharbee Hussein Al

    2018-01-01

    Full Text Available This paper proposes a vibration-based methodology for fault detection in rolling element bearings, which is based on pure data analysis via singular spectrum method. The method suggests building a baseline space from feature vectors made of the signals measured in the healthy/baseline bearing condition. The feature vectors are made using the Euclidean norms of the first three PC’s found for the signals measured. Then, the lagged version of any new signal corresponding to a new (possibly faulty condition is projected onto this baseline feature space in order to assess its similarity to the baseline condition. The category of a new signal vector is determined based on the Mahalanobis distance (MD of its feature vector to the baseline space. A validation of the methodology is suggested based on the results from an experimental test rig. The results obtained confirm the effective performance of the suggested methodology. It is made of simple steps and is easy to apply with a perspective to make it automatic and suitable for commercial applications.

  13. Approximate solution of oil film load-carrying capacity of turbulent journal bearing with couple stress flow

    Science.gov (United States)

    Zhang, Yongfang; Wu, Peng; Guo, Bo; Lü, Yanjun; Liu, Fuxi; Yu, Yingtian

    2015-01-01

    The instability of the rotor dynamic system supported by oil journal bearing is encountered frequently, such as the half-speed whirl of the rotor, which is caused by oil film lubricant with nonlinearity. Currently, more attention is paid to the physical characteristics of oil film due to an oil-lubricated journal bearing being the important supporting component of the bearing-rotor systems and its nonlinear nature. In order to analyze the lubrication characteristics of journal bearings efficiently and save computational efforts, an approximate solution of nonlinear oil film forces of a finite length turbulent journal bearing with couple stress flow is proposed based on Sommerfeld and Ocvirk numbers. Reynolds equation in lubrication of a finite length turbulent journal bearing is solved based on multi-parametric principle. Load-carrying capacity of nonlinear oil film is obtained, and the results obtained by different methods are compared. The validation of the proposed method is verified, meanwhile, the relationships of load-carrying capacity versus eccentricity ratio and width-to-diameter ratio under turbulent and couple stress working conditions are analyzed. The numerical results show that both couple stress flow and eccentricity ratio have obvious influence on oil film pressure distribution, and the proposed method approximates the load-carrying capacity of turbulent journal bearings efficiently with various width-to-diameter ratios. This research proposes an approximate solution of oil film load-carrying capacity of turbulent journal bearings with different width-to-diameter ratios, which are suitable for high eccentricity ratios and heavy loads.

  14. A Comparative Experimental Study on Identification of Defect Severity in Rolling Element Bearings using Acoustic Emission and Vibration Analysis

    Directory of Open Access Journals (Sweden)

    V.V. Rao

    2015-06-01

    Full Text Available This paper describes the comparison between Vibration Analysis (VA and Acoustic Emission (AE method to predict the defect severity in rolling element bearings with respect to the gradual increase of defect size. In bearing fault diagnosis vibration based methods are very popular, but the signals acquired by its transducers from the bearings are distorted by other faults and mechanical noise from the equipment. Vibration based methods are effective when the defect in the bearings has already become severe. AE is a non destructive testing (NDT technique used in structural health monitoring and its application for bearing defect diagnosis is gaining momentum as an alternate diagnostic tool because of its inherent high signal-to-noise-ratio (SNR. A bearing test rig was designed and set up to study the various defects in rolling element bearings in real environment. In earlier cases, though the researchers studied on different types of seeded defects with random sizes, they could not ascertain the correlation between their defect sizes and the vibration amplitude. The experimental investigation reported in this paper is centered on seeded defect of same type with gradual increase of its size on outer race of radially loaded cylindrical roller bearings and running the defective bearing at different speeds and loads. Data acquired through AE & vibration probes simultaneously for better diagnosis. Comparisons between AE and VA over a range of speed and load conditions at gradual increase of defect size are presented and from them it is concluded that AE method is superior to identify the severity of defect.

  15. Finite-element simulations of coupling capacitances in capacitively coupled pixel detectors

    CERN Document Server

    AUTHOR|(SzGeCERN)755510

    2017-01-01

    Capacitively coupled hybrid silicon pixel-detector assemblies are under study for the vertex detector at the proposed future CLIC linear electron-positron collider. The assemblies consist of active CCPDv3 sensors, with 25 μm pixel pitch implemented in a 180 nm High- Voltage CMOS process, which are glued to the CLICpix readout ASIC, with the same pixel pitch and processed in a commercial 65 nm CMOS technology. The signal created in the silicon bulk of the active sensors passes a two-stage amplifier, in each pixel, and gets transferred as a voltage pulse to metal pads facing the readout chip (ROC). The coupling of the signal to the metal pads on the ROC side proceeds through the capacitors formed between the two chips by a thin layer of epoxy glue. The coupling strength and the amount of unwanted cross coupling to neighbouring pixels depends critically on the uniformity of the glue layer, its thickness and on the alignment precision during the flip-chip assembly process. Finite-element calculations of the coup...

  16. Investigating the use of multi-point coupling for single-sensor bearing estimation in one direction

    Science.gov (United States)

    Woolard, Americo G.; Phoenix, Austin A.; Tarazaga, Pablo A.

    2018-04-01

    Bearing estimation of radially propagating symmetric waves in solid structures typically requires a minimum of two sensors. As a test specimen, this research investigates the use of multi-point coupling to provide directional inference using a single-sensor. By this provision, the number of sensors required for localization can be reduced. A finite-element model of a beam is constructed with a symmetrically placed bipod that has asymmetric joint-stiffness properties. Impulse loading is applied at different points along the beam, and measurements are taken from the apex of the bipod. A technique is developed to determine the direction-of-arrival of the propagating wave. The accuracy when using the bipod with the developed technique is compared against results gathered without the bipod and measuring from an asymmetric location along the beam. The results show 92% accuracy when the bipod is used, compared to 75% when measuring without the bipod from an asymmetric location. A geometry investigation finds the best accuracy results when one leg of the bipod has a low stiffness and a large diameter relative to the other leg.

  17. On diversity performance of two-element coupling element based antenna structure for mobile terminal

    DEFF Research Database (Denmark)

    Al-Hadi, Azremi Abdullah; Toivanen, Juha; Laitinen, Tommi

    2010-01-01

    .1 and the diversity gain is equal to 10.2 dB at 99% reliability level using selection combining technique across simulation and both measurement methods. The measurement techniques are compared to show how accurately the diversity performance of a mobile terminal antenna can be estimated.......In wireless communication systems, multipath interference has a significant impact on system design and performance. Fast fading is caused by the coherent summation of one or more echoes from many reflection points reaching the receive antenna. Antenna diversity can be used to mitigate multipath...... fading. The main challenge of antenna diversity in practical application is the integration of multiple antennas on a small ground plane. Two-element antenna structure based on coupling element antenna concept for diversity application has been studied in previous work and it has shown to be feasible...

  18. Geographic distribution of selected elements in the livers of polar bears from Greenland, Canada and the United States

    International Nuclear Information System (INIS)

    Rush, Scott A.; Borga, Katrine; Dietz, Rune; Born, Erik W.; Sonne, Christian; Evans, Thomas; Muir, Derek C.G.; Letcher, Robert J.; Norstrom, Ross J.; Fisk, Aaron T.

    2008-01-01

    To assess geographic distributions of elements in the Arctic we compared essential and non-essential elements in the livers of polar bears (Ursus maritimus) collected from five regions within Canada in 2002, in Alaska between 1994 and 1999 and from the northwest and east coasts of Greenland between 1988 and 2000. As, Hg, Pb and Se varied with age, and Co and Zn with gender, which limited spatial comparisons across all populations to Cd, which was highest in Greenland bears. Collectively, geographic relationships appeared similar to past studies with little change in concentration over time in Canada and Greenland for most elements; Hg and Se were higher in some Canadian populations in 2002 as compared to 1982 and 1984. Concentrations of most elements in the polar bears did not exceed toxicity thresholds, although Cd and Hg exceeded levels correlated with the formation of hepatic lesions in laboratory animals. - Geographical trends were observed for a number of elements in livers, including mercury, of polar bears collected across Alaska, Canada and Greenland and were similar to those observed in the early 1980s

  19. Compensation of Cross-Coupling Stiffness and Increase of Direct Damping in Multirecess Journal Bearings using Active Hybrid Lubrication

    DEFF Research Database (Denmark)

    Santos, Ilmar; Watanabe, F.Y.

    2004-01-01

    journal bearings (HJB). When part of hydrostatic pressure is also dynamically modified by means of hydraulic control systems, one refers to the active lubrication. The main contribution of the present theoretical work is to show that it is possible to reduce cross-coupling stiffness and increase...

  20. Finite element analysis on the electromagnetic fields of active magnetic bearing

    Energy Technology Data Exchange (ETDEWEB)

    Ren, S; Liu, J [School of Mechanical Engineering, Shenyang Ligong University, Shenyang, 110168 (China); Bian, C [Institute of Information Science and Engineering, Northeastern University, Shenyang, 110004 (China)], E-mail: renshy@sina.com

    2008-02-15

    To increase the carrying capacity and reduce the weight and size of AMBs, it is necessary to use a ferromagnetic material with high magnetic flux density, which can make AMBs run in the nonlinear region. The simple linear model before is not gratifying, so some more precise analysis methods are demanded, the finite element method(shorted as FEM) is one of such methods. In this paper, the mathematic model and the simplified calculation of AMB rotor are introduced, and the finite elemental model and its boundary condition are produced. Then, the coupling phenomena of the magnetic fields and the effects of different parameters on the magnetic fields of AMB with a non-homocentric rotor are simulated using the FEM analysis software of ANSYS. The distributions of 2D magnetic lines of force and the flux density in rotor and stator are given. The conclusions are of instructed meaning for the design of AMBs.

  1. Finite element analysis on the electromagnetic fields of active magnetic bearing

    International Nuclear Information System (INIS)

    Ren, S; Liu, J; Bian, C

    2008-01-01

    To increase the carrying capacity and reduce the weight and size of AMBs, it is necessary to use a ferromagnetic material with high magnetic flux density, which can make AMBs run in the nonlinear region. The simple linear model before is not gratifying, so some more precise analysis methods are demanded, the finite element method(shorted as FEM) is one of such methods. In this paper, the mathematic model and the simplified calculation of AMB rotor are introduced, and the finite elemental model and its boundary condition are produced. Then, the coupling phenomena of the magnetic fields and the effects of different parameters on the magnetic fields of AMB with a non-homocentric rotor are simulated using the FEM analysis software of ANSYS. The distributions of 2D magnetic lines of force and the flux density in rotor and stator are given. The conclusions are of instructed meaning for the design of AMBs

  2. Resilient and Corrosion-Proof Rolling Element Bearings Made from Superelastic Ni-Ti Alloys for Aerospace

    Science.gov (United States)

    Dellacorte, Christopher

    2014-01-01

    Mechanical components (bearings, gears, mechanisms) typically utilize hardened construction materials to minimize wear and attain long life. In such components, loaded contact points (e.g., meshing gear teeth, bearing balls-raceway contacts) experience high contact stresses. The combination of high hardness and high elastic modulus often leads to damaging contact stress and denting, particularly during transient overload events such as shock impacts that occur during the launching of space vehicles or the landing of aircraft. In this webinar, Dr. DellaCorte will introduce the results of a research project that employs a superelastic alloy, Ni-Ti for rolling element bearing applications. Bearings and components made from such alloys can alleviate many problems encountered in advanced aerospace applications and may solve many terrestrial applications as well

  3. Numerical Simulation and Experimental Study on the Gas-Solid Coupling of the Aerostatic Thrust Bearing with Elastic Equalizing Pressure Groove

    Directory of Open Access Journals (Sweden)

    Zhao Xiao-long

    2017-01-01

    Full Text Available Aiming at the problem of low stiffness of aerostatic bearing, according to the principle of gas-solid coupling, this paper designs a kind of aerostatic thrust bearing with elastic equalizing pressure groove (EEPG and investigates the effect of elastic equalizing pressure groove (EEPG on the stiffness of aerostatic bearing. According to the physical model of the bearing, one deduces the deformation control equation of the elastic equalizing pressure groove and the control equation of gas lubrication, using finite difference method to derive the control equations and coupling calculation. The bearing capacity and stiffness of aerostatic bearing with EEPG in different gas film clearance are obtained. The calculation results show that the stiffness increased by 59%. The results of numerical calculation and experimental results have good consistency, proving the gas-solid coupling method can improve the bearing stiffness.

  4. Redistribution of elements between wastes and organic-bearing material in the dispersion train of gold-bearing sulfide tailings: Part I. Geochemistry and mineralogy.

    Science.gov (United States)

    Saryg-Ool, B Yu; Myagkaya, I N; Kirichenko, I S; Gustaytis, M A; Shuvaeva, O V; Zhmodik, S M; Lazareva, E V

    2017-03-01

    Migration and redistribution of elements during prolonged interaction of cyanide wastes with the underlying natural organic-bearing material have been studied in two ~40cm deep cores that sample primary ores and their weathering profile (wastes I and II, respectively) in the dispersion train of gold-bearing sulfide tailings in Siberia. Analytical results of SR-XRF, whole-rock XRF, AAS, CHNS, and SEM measurements of core samples show high K, Sr, Ti, and Fe enrichments and correlation of P 2 O 5 and Mn with LOI and C org . Organic material interlayered or mixed with the wastes accumulates Cu, Zn, Se, Cd, Ag, Au, and Hg. The peat that contacts wastes II bears up to 3wt.% Zn, 1000g/t Se, 100g/t Cd, and 8000g/t Hg. New phases of Zn and Hg sulfides and Hg selenides occur as abundant sheaths over bacterial cells suggesting microbial mediation in sorption of elements. Organic-bearing material in the cores contains 10-30g/t Au in 2-5cm thick intervals, both within and outside the intervals rich in sulfides and selenides. Most of gold is invisible but reaches 345g/t and forms 50nm to 1.5μm Au 0 particles in a thin 2-3cm interval of organic remnants mixed with wastes I. Vertical and lateral infiltration of AMD waters in peat and oxidative dissolution of wastes within the dispersion train of the Ursk tailings lead to redistribution of elements and their accumulation by combined physical (material's permeability, direction AMD), chemical (complexing, sorption by organic matter and Fe(III) hydroxides) and biochemical (metabolism of sulfate-reducing bacteria) processes. The accumulated elements form secondary sulfates, and Hg and Zn selenides. The results provide insights into accumulation of elements in the early history of coal and black shale deposits and have implications for remediation of polluted areas and for secondary enrichment technologies. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Nonlinear dynamic behaviour of a rotor-foundation system coupled through passive magnetic bearings with magnetic anisotropy - Theory and experiment

    DEFF Research Database (Denmark)

    Enemark, Søren; Santos, Ilmar F.

    2016-01-01

    In this work, the nonlinear dynamic behaviour of a vertical rigid rotor interacting with a flexible foundation by means of two passive magnetic bearings is quantified and evaluated. The quantification is based on theoretical and experimental investigation of the non-uniformity (anisotropy......) of the magnetic field and the weak nonlinearity of the magnetic forces. Through mathematical modelling the nonlinear equations of motion are established for describing the shaft and bearing housing lateral dynamics coupled via the nonlinear and non-uniform magnetic forces. The equations of motion are solved...

  6. Using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to characterize copper, zinc and mercury along grizzly bear hair providing estimate of diet

    Energy Technology Data Exchange (ETDEWEB)

    Noël, Marie, E-mail: marie.noel@stantec.com [Stantec Consulting Ltd. 2042 Mills Road, Unit 11, Sidney BC V8L 4X2 (Canada); Christensen, Jennie R., E-mail: jennie.christensen@stantec.com [Stantec Consulting Ltd. 2042 Mills Road, Unit 11, Sidney BC V8L 4X2 (Canada); Spence, Jody, E-mail: jodys@uvic.ca [School of Earth and Ocean Sciences, Bob Wright Centre A405, University of Victoria, PO BOX 3065 STN CSC, Victoria, BC V8W 3V6 (Canada); Robbins, Charles T., E-mail: ctrobbins@wsu.edu [School of the Environment and School of Biological Sciences, Washington State University, Pullman, WA 99164-4236 (United States)

    2015-10-01

    We enhanced an existing technique, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), to function as a non-lethal tool in the temporal characterization of trace element exposure in wild mammals. Mercury (Hg), copper (Cu), cadmium (Cd), lead (Pb), iron (Fe) and zinc (Zn) were analyzed along the hair of captive and wild grizzly bears (Ursus arctos horribilis). Laser parameters were optimized (consecutive 2000 μm line scans along the middle line of the hair at a speed of 50 μm/s; spot size = 30 μm) for consistent ablation of the hair. A pressed pellet of reference material DOLT-2 and sulfur were used as external and internal standards, respectively. Our newly adapted method passed the quality control tests with strong correlations between trace element concentrations obtained using LA-ICP-MS and those obtained with regular solution-ICP-MS (r{sup 2} = 0.92, 0.98, 0.63, 0.57, 0.99 and 0.90 for Hg, Fe, Cu, Zn, Cd and Pb, respectively). Cross-correlation analyses revealed good reproducibility between trace element patterns obtained from hair collected from the same bear. One exception was Cd for which external contamination was observed resulting in poor reproducibility. In order to validate the method, we used LA-ICP-MS on the hair of five captive grizzly bears fed known and varying amounts of cutthroat trout over a period of 33 days. Trace element patterns along the hair revealed strong Hg, Cu and Zn signals coinciding with fish consumption. Accordingly, significant correlations between Hg, Cu, and Zn in the hair and Hg, Cu, and Zn intake were evident and we were able to develop accumulation models for each of these elements. While the use of LA-ICP-MS for the monitoring of trace elements in wildlife is in its infancy, this study highlights the robustness and applicability of this newly adapted method. - Highlights: • LA-ICP-MS provides temporal trace metal exposure information for wild grizzly bears. • Cu and Zn temporal exposures provide

  7. Using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to characterize copper, zinc and mercury along grizzly bear hair providing estimate of diet

    International Nuclear Information System (INIS)

    Noël, Marie; Christensen, Jennie R.; Spence, Jody; Robbins, Charles T.

    2015-01-01

    We enhanced an existing technique, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), to function as a non-lethal tool in the temporal characterization of trace element exposure in wild mammals. Mercury (Hg), copper (Cu), cadmium (Cd), lead (Pb), iron (Fe) and zinc (Zn) were analyzed along the hair of captive and wild grizzly bears (Ursus arctos horribilis). Laser parameters were optimized (consecutive 2000 μm line scans along the middle line of the hair at a speed of 50 μm/s; spot size = 30 μm) for consistent ablation of the hair. A pressed pellet of reference material DOLT-2 and sulfur were used as external and internal standards, respectively. Our newly adapted method passed the quality control tests with strong correlations between trace element concentrations obtained using LA-ICP-MS and those obtained with regular solution-ICP-MS (r 2 = 0.92, 0.98, 0.63, 0.57, 0.99 and 0.90 for Hg, Fe, Cu, Zn, Cd and Pb, respectively). Cross-correlation analyses revealed good reproducibility between trace element patterns obtained from hair collected from the same bear. One exception was Cd for which external contamination was observed resulting in poor reproducibility. In order to validate the method, we used LA-ICP-MS on the hair of five captive grizzly bears fed known and varying amounts of cutthroat trout over a period of 33 days. Trace element patterns along the hair revealed strong Hg, Cu and Zn signals coinciding with fish consumption. Accordingly, significant correlations between Hg, Cu, and Zn in the hair and Hg, Cu, and Zn intake were evident and we were able to develop accumulation models for each of these elements. While the use of LA-ICP-MS for the monitoring of trace elements in wildlife is in its infancy, this study highlights the robustness and applicability of this newly adapted method. - Highlights: • LA-ICP-MS provides temporal trace metal exposure information for wild grizzly bears. • Cu and Zn temporal exposures provide

  8. Use of high frequency analysis of acoustic emission signals to determine rolling element bearing condition

    International Nuclear Information System (INIS)

    Cockerill, A; Holford, K M; Pullin, R; Clarke, A; Bradshaw, T; Cole, P

    2015-01-01

    Acoustic Emission (AE) sensors were used to detect signals arising from a cylindrical roller bearing with artificial defects seeded onto the outer raceway. An SKF N204ECP roller bearing was placed between two double row spherical roller bearings, type SKF 22202E, and loaded between 0.29 and 1.79kN. Speed was constant at 5780rpm. High frequency analysis allowed insight into the condition of the bearings through the determination of an increase in the structural resonances of the system as the size of an artificial defect was increased. As higher loads were applied, frequencies around 100kHz were excited, indicating the release of AE possibly attributed to friction and the plastic deformation as peaks, induced through engraving of the raceway, were flattened and worn down. Sensitivity of AE to this level in bearings indicates the potential of the technique to detect the early stages of bearing failure during life tests. (paper)

  9. Stable isotope and trace element studies of black bear hair, Big Bend ecosystem, Texas and Mexico

    Science.gov (United States)

    Shanks, W.C. Pat; Hellgren, Eric C.; Stricker, Craig A.; Gemery-Hill, Pamela A.; Onorato, David P.

    2008-01-01

    Hair from black bears (Ursus americanus), collected from four areas in the Big Bend ecosystem, has been analyzed for stable isotopes of carbon, nitrogen, and sulfur to determine major food sources and for trace metals to infer possible effects of environmental contaminants. Results indicate that black bears are largely vegetarian, feeding on desert plants, nuts, and berries. Mercury concentrations in bear hair are below safe level standards (

  10. Co-simulation coupling spectral/finite elements for 3D soil/structure interaction problems

    Science.gov (United States)

    Zuchowski, Loïc; Brun, Michael; De Martin, Florent

    2018-05-01

    The coupling between an implicit finite elements (FE) code and an explicit spectral elements (SE) code has been explored for solving the elastic wave propagation in the case of soil/structure interaction problem. The coupling approach is based on domain decomposition methods in transient dynamics. The spatial coupling at the interface is managed by a standard coupling mortar approach, whereas the time integration is dealt with an hybrid asynchronous time integrator. An external coupling software, handling the interface problem, has been set up in order to couple the FE software Code_Aster with the SE software EFISPEC3D.

  11. Predicting the response of high damping rubber bearings using simplified models and finite element analysis

    International Nuclear Information System (INIS)

    Fuller, K.N.G.; Gough, J.; Ahmadi, H.R.

    1993-01-01

    The International Atomic Energy Agency has initiated a co-ordinated research programme on implementation of base-isolation for nuclear structures. This paper discusses two areas relevant to modelling elastomeric base-isolators. These are the use of simplified models to predict the response of isolated structures to earthquake inputs and finite element analysis for calculating the stress distributions within the isolators. In the former, a curvilinear hysteretic model of the high damping natural rubber able to accommodate the stiffening of the rubber at large shear deflections is presented. Its predictions of structural accelerations and bearing displacement produced by design earthquakes and those above the design level are compared with those using a linear spring and dashpot model. A comparison has been made between two finite element analyses using MARC and ABAQUS of the force-deformation behaviour of a single disc of rubber bonded on both sides. The disc was loaded both in compression and shear. Two forms of strain energy functions were used namely Mooney-RivIin and Ogden. The agreement between MARC and ABAQUS for the Mooney-Rivlin model for the material was very good. This was not however the case for the Ogden model and a difference of 25% in the maximum vertical deflection of the disc under 200kN load was observed. The need for a 'benchmark' problem is identified. This could be used to establish the accuracy of the finite element solvers. A problem based on the work of Rivlin on the force-deformation behaviour of cylinder of rubber under torsion is nominated. An appraisal of strain energy functions based on Mooney-RivIin formulations is carried out. It is shown that even for a five term series the strain energy function is incapable of catering for the rapid change of modulus at small strains both for simple and pure shear modes of deformation. This function models tension/compression data much better. The work identifies the need for evaluating other forms

  12. Contact stresses, pressure and area in a fixed-bearing total ankle replacement: a finite element analysis.

    Science.gov (United States)

    Martinelli, Nicolo; Baretta, Silvia; Pagano, Jenny; Bianchi, Alberto; Villa, Tomaso; Casaroli, Gloria; Galbusera, Fabio

    2017-11-25

    Mobile-bearing ankle implants with good clinical results continued to increase the popularity of total ankle arthroplasty to address endstage ankle osteoarthritis preserving joint movement. Alternative solutions used fixed-bearing designs, which increase stability and reduce the risk of bearing dislocation, but with a theoretical increase of contact stresses leading to a higher polyethylene wear. The purpose of this study was to investigate the contact stresses, pressure and area in the polyethylene component of a new total ankle replacement with a fixed-bearing design, using 3D finite element analysis. A three-dimensional finite element model of the Zimmer Trabecular Metal Total Ankle was developed and assembled based on computed tomography images. Three different sizes of the polyethylene insert were modeled, and a finite element analysis was conducted to investigate the contact pressure, the von Mises stresses and the contact area of the polyethylene component during the stance phase of the gait cycle. The peak value of pressure was found in the anterior region of the articulating surface, where it reached 19.8 MPa at 40% of the gait cycle. The average contact pressure during the stance phase was 6.9 MPa. The maximum von Mises stress of 14.1 MPa was reached at 40% of the gait cycle in the anterior section. In the central section, the maximum von Mises stress of 10.8 MPa was reached at 37% of the gait cycle, whereas in the posterior section the maximum stress of 5.4 MPa was reached at the end of the stance phase. The new fixed-bearing total ankle replacement showed a safe mechanical behavior and many clinical advantages. However, advanced models to quantitatively estimate the wear are need. To the light of the clinical advantages, we conclude that the presented prosthesis is a good alternative to the other products present in the market.

  13. Resilient and Corrosion-Proof Rolling Element Bearings Made from Superelastic Ni-Ti Alloys for Aerospace Mechanism Applications

    Science.gov (United States)

    DellaCorte, Christopher; Noebe, Ronald D.; Stanford, Malcolm; Padula, Santo A.

    2011-01-01

    Mechanical components (bearings, gears, mechanisms) typically utilize hard materials to minimize wear and attain long life. In such components, heavily loaded contact points (e.g., meshing gear teeth, bearing ball-raceway contacts) experience high contact stresses. The combination of high hardness, heavy loads and high elastic modulus often leads to damaging contact stress. In addition, mechanical component materials, such as tool steel or silicon nitride exhibit limited recoverable strain (typically less than 1 percent). These material attributes can lead to Brinell damage (e.g., denting) particularly during transient overload events such as shock impacts that occur during the launching of space vehicles or the landing of aircraft. In this paper, a superelastic alloy, 60NiTi, is considered for rolling element bearing applications. A series of Rockwell and Brinell hardness, compressive strength, fatigue and tribology tests are conducted and reported. The combination of high hardness, moderate elastic modulus, large recoverable strain, low density, and intrinsic corrosion immunity provide a path to bearings largely impervious to shock load damage. It is anticipated that bearings and components made from alloys with such attributes can alleviate many problems encountered in advanced aerospace applications.

  14. A fully coupled finite element framework for thermal fracturing simulation in subsurface cold CO2 injection

    Directory of Open Access Journals (Sweden)

    Shunde Yin

    2018-03-01

    Simulation of thermal fracturing during cold CO2 injection involves the coupled processes of heat transfer, mass transport, rock deforming as well as fracture propagation. To model such a complex coupled system, a fully coupled finite element framework for thermal fracturing simulation is presented. This framework is based on the theory of non-isothermal multiphase flow in fracturing porous media. It takes advantage of recent advances in stabilized finite element and extended finite element methods. The stabilized finite element method overcomes the numerical instability encountered when the traditional finite element method is used to solve the convection dominated heat transfer equation, while the extended finite element method overcomes the limitation with traditional finite element method that a model has to be remeshed when a fracture is initiated or propagating and fracturing paths have to be aligned with element boundaries.

  15. Automatic Condition Monitoring of Industrial Rolling-Element Bearings Using Motor’s Vibration and Current Analysis

    DEFF Research Database (Denmark)

    Yang, Zhenyu

    2015-01-01

    An automatic condition monitoring for a class of industrial rolling-element bearings is developed based on the vibration as well as stator current analysis. The considered fault scenarios include a single-point defect, multiple-point defects, and a type of distributed defect. Motivated by the pot...... characteristic frequencies, sideband effects, time-average of spectra, and selection of fault index and thresholds, are also discussed. The experimental work shows a huge potential to use some simple methods for successful diagnosis of industrial bearing systems.......An automatic condition monitoring for a class of industrial rolling-element bearings is developed based on the vibration as well as stator current analysis. The considered fault scenarios include a single-point defect, multiple-point defects, and a type of distributed defect. Motivated...... is extensively studied under diverse operating conditions: different sensor locations, motor speeds, loading conditions, and data samples from different time segments. The experimental results showed the powerful capability of vibration analysis in the bearing point defect fault diagnosis. The current analysis...

  16. Performance of two-lobe hole-entry hybrid journal bearing system under the combined influence of textured surface and couple stress lubricant

    Science.gov (United States)

    Khatri, Chandra B.; Sharma, Satish C.

    2018-02-01

    Textured surface in journal bearings is becoming an important area of investigation during the last few years. Surface textures have the shapes of micro-dimple with a small diameter and depth having order of magnitude of bearing clearance. This paper presents the influence of couple stress lubricant on the circular and non-circular hole-entry hybrid journal bearing system and reports the comparative study between the textured and non-textured circular/non-circular hybrid journal bearing system. The governing Reynolds equation has been modified for the couple stress lubricant flow in the clearance of bearing and journal. The FEM technique has been applied to solve the modified Reynolds equation together with restrictor flow equation. The numerically simulated results indicate that the influence of couple stress lubricant is significantly more in textured journal bearing than that of non-textured journal bearing. Further, it has been observed that the textured two-lobe (δ = 1.1) hybrid journal bearing lubricated with couple stress lubricant provides larger values of fluid film stiffness coefficients and stability threshold speed against other bearings studied in the present paper.

  17. Phase reduction and synchronization of a network of coupled dynamical elements exhibiting collective oscillations

    Science.gov (United States)

    Nakao, Hiroya; Yasui, Sho; Ota, Masashi; Arai, Kensuke; Kawamura, Yoji

    2018-04-01

    A general phase reduction method for a network of coupled dynamical elements exhibiting collective oscillations, which is applicable to arbitrary networks of heterogeneous dynamical elements, is developed. A set of coupled adjoint equations for phase sensitivity functions, which characterize the phase response of the collective oscillation to small perturbations applied to individual elements, is derived. Using the phase sensitivity functions, collective oscillation of the network under weak perturbation can be described approximately by a one-dimensional phase equation. As an example, mutual synchronization between a pair of collectively oscillating networks of excitable and oscillatory FitzHugh-Nagumo elements with random coupling is studied.

  18. Finite element procedures for coupled linear analysis of heat transfer, fluid and solid mechanics

    Science.gov (United States)

    Sutjahjo, Edhi; Chamis, Christos C.

    1993-01-01

    Coupled finite element formulations for fluid mechanics, heat transfer, and solid mechanics are derived from the conservation laws for energy, mass, and momentum. To model the physics of interactions among the participating disciplines, the linearized equations are coupled by combining domain and boundary coupling procedures. Iterative numerical solution strategy is presented to solve the equations, with the partitioning of temporal discretization implemented.

  19. Coupled distinct element-finite element numerical modelling of fluid circulation in deforming sedimentary basins.

    Science.gov (United States)

    Hindle, D.; Malz, A.; Donndorf, S.; Kley, J.; Kopp, H.

    2012-04-01

    We develop a coupled numerical model for fluid flow in deforming sedimentary basins. We combine a distinct element method for large deformations of crustal materials, with a finite element method for fluid flow according to a diffusion type equation. The key question in such a model is how to simulate evolving permeabilities due to upper and possibly middle crustal deformation, and the coupled issue of how localisation of deformation in faults and shear zones is itself influenced by fluid flow and fluid pressure and vice versa. Currently our knowledge of these issues is restricted, even sketchy. There are a number of hypotheses, based partly on geological and isotope geochemical observations, such as "seismic pumping" models, and fluid induced weak décollement models for thrust sheet transport which have gained quite wide acceptance. Observations around thrusts at the present day have also often been interpreted as showing deformation induced permeability. However, combining all the physics of these processes into a numerical simulation is a complicated task given the ranges of, in particular time scales of the processes we infer to be operating based on our various observations. We start this task by using an elastic fracture relationship between normal stresses across distinct element contacts (which we consider to be the equivalent of discrete, sliding fractures) and their openness and hence their transmissivity. This relates the mechanical state of the distinct element system to a discrete permeability field. Further than that, the geometry of the mechanical system is used to provide boundary conditions for fluid flow in a diffusion equation which also incorporates the permeability field. The next question we address is how to achieve a feedback between fluid pressures and deformation. We try two approaches: one treats pore space in the DEM as real, and calculates the force exerted locally by fluids and adds this to the force balance of the model; another

  20. Application of support vector machine based on pattern spectrum entropy in fault diagnostics of rolling element bearings

    International Nuclear Information System (INIS)

    Hao, Rujiang; Chu, Fulei; Peng, Zhike; Feng, Zhipeng

    2011-01-01

    This paper presents a novel pattern classification approach for the fault diagnostics of rolling element bearings, which combines the morphological multi-scale analysis and the 'one to others' support vector machine (SVM) classifiers. The morphological pattern spectrum describes the shape characteristics of the inspected signal based on the morphological opening operation with multi-scale structuring elements. The pattern spectrum entropy and the barycenter scale location of the spectrum curve are extracted as the feature vectors presenting different faults of the bearing, which are more effective and representative than the kurtosis and the enveloping demodulation spectrum. The 'one to others' SVM algorithm is adopted to distinguish six kinds of fault signals which were measured in the experimental test rig under eight different working conditions. The recognition results of the SVM are ideal and more precise than those of the artificial neural network even though the training samples are few. The combination of the morphological pattern spectrum parameters and the 'one to others' multi-class SVM algorithm is suitable for the on-line automated fault diagnosis of the rolling element bearings. This application is promising and worth well exploiting

  1. Estimating black bear density in New Mexico using noninvasive genetic sampling coupled with spatially explicit capture-recapture methods

    Science.gov (United States)

    Gould, Matthew J.; Cain, James W.; Roemer, Gary W.; Gould, William R.

    2016-01-01

    During the 2004–2005 to 2015–2016 hunting seasons, the New Mexico Department of Game and Fish (NMDGF) estimated black bear abundance (Ursus americanus) across the state by coupling density estimates with the distribution of primary habitat generated by Costello et al. (2001). These estimates have been used to set harvest limits. For example, a density of 17 bears/100 km2 for the Sangre de Cristo and Sacramento Mountains and 13.2 bears/100 km2 for the Sandia Mountains were used to set harvest levels. The advancement and widespread acceptance of non-invasive sampling and mark-recapture methods, prompted the NMDGF to collaborate with the New Mexico Cooperative Fish and Wildlife Research Unit and New Mexico State University to update their density estimates for black bear populations in select mountain ranges across the state.We established 5 study areas in 3 mountain ranges: the northern (NSC; sampled in 2012) and southern Sangre de Cristo Mountains (SSC; sampled in 2013), the Sandia Mountains (Sandias; sampled in 2014), and the northern (NSacs) and southern Sacramento Mountains (SSacs; both sampled in 2014). We collected hair samples from black bears using two concurrent non-invasive sampling methods, hair traps and bear rubs. We used a gender marker and a suite of microsatellite loci to determine the individual identification of hair samples that were suitable for genetic analysis. We used these data to generate mark-recapture encounter histories for each bear and estimated density in a spatially explicit capture-recapture framework (SECR). We constructed a suite of SECR candidate models using sex, elevation, land cover type, and time to model heterogeneity in detection probability and the spatial scale over which detection probability declines. We used Akaike’s Information Criterion corrected for small sample size (AICc) to rank and select the most supported model from which we estimated density.We set 554 hair traps, 117 bear rubs and collected 4,083 hair

  2. Determination of metallo-organic and particulate wear metals in lubricating oils associated with hybrid ceramic bearings by inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Russell, Robin Ann

    It is possible to increase both the performance and operating environment of jet engines by using hybrid ceramic bearings. Our laboratory is concerned with investigating lubricating fluids for wear metals associated with silicon nitride ball bearings and steel raceways. Silicon nitride is characterized by low weight, low thermal expansion, high strength, and corrosion resistance. These attributes result in longer engine lifetimes than when metallic ball bearings are used. Before the routine use of ceramic ball bearings can be realized, the wear mechanisms of the materials should be thoroughly understood. One important variable in determining wear degradation is the concentration of metal present in the lubricating oils used with the bearings. A complete method for analyzing used lubricating oils for wear metal content must accurately determine all metal forms present. Oil samples pose problems for routine analysis due to complex organic matrices. Nebulizing these types of samples into an Inductively Coupled Plasma - Mass Spectrometer introduces many problems including clogging of the sample cone with carbon and increasing interferences. In addition, other techniques such as Atomic Absorption Spectrometry and Atomic Emission Spectrometry are particle size dependent. They are unable to analyze particles greater than 10 mum in size. This dissertation describes a method of analyzing lubricating oils for both metallo-organic and particulate species by ICP-MS. Microwave digestion of the oil samples eliminates the need for elaborate sample introduction schemes as well as the use of a modified carrier gas. Al, Cr, Fe, Mg, Mo, Ni, Ti, and Y have been determined in both aqueous and organic media. Metallo-organic solutions of these metals were successfully digested, nebulized into the ICP, and the singly charged ions measured by mass spectrometry. Metal particulates in oil matrices have also been quantitatively determined by the above method. Linear analytical curves were

  3. Generalized multiscale finite element method. Symmetric interior penalty coupling

    KAUST Repository

    Efendiev, Yalchin R.; Galvis, Juan; Lazarov, Raytcho D.; Moon, M.; Sarkis, Marcus V.

    2013-01-01

    Motivated by applications to numerical simulations of flows in highly heterogeneous porous media, we develop multiscale finite element methods for second order elliptic equations. We discuss a multiscale model reduction technique in the framework of the discontinuous Galerkin finite element method. We propose two different finite element spaces on the coarse mesh. The first space is based on a local eigenvalue problem that uses an interior weighted L2-norm and a boundary weighted L2-norm for computing the "mass" matrix. The second choice is based on generation of a snapshot space and subsequent selection of a subspace of a reduced dimension. The approximation with these multiscale spaces is based on the discontinuous Galerkin finite element method framework. We investigate the stability and derive error estimates for the methods and further experimentally study their performance on a representative number of numerical examples. © 2013 Elsevier Inc.

  4. Generalized multiscale finite element method. Symmetric interior penalty coupling

    KAUST Repository

    Efendiev, Yalchin R.

    2013-12-01

    Motivated by applications to numerical simulations of flows in highly heterogeneous porous media, we develop multiscale finite element methods for second order elliptic equations. We discuss a multiscale model reduction technique in the framework of the discontinuous Galerkin finite element method. We propose two different finite element spaces on the coarse mesh. The first space is based on a local eigenvalue problem that uses an interior weighted L2-norm and a boundary weighted L2-norm for computing the "mass" matrix. The second choice is based on generation of a snapshot space and subsequent selection of a subspace of a reduced dimension. The approximation with these multiscale spaces is based on the discontinuous Galerkin finite element method framework. We investigate the stability and derive error estimates for the methods and further experimentally study their performance on a representative number of numerical examples. © 2013 Elsevier Inc.

  5. Journal bearing

    Science.gov (United States)

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

    1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

  6. Energy Harvesting with Piezoelectric Element Using Vibroacoustic Coupling Phenomenon

    Directory of Open Access Journals (Sweden)

    Hiroyuki Moriyama

    2013-01-01

    Full Text Available This paper describes the vibroacoustic coupling between the structural vibrations and internal sound fields of thin structures. In this study, a cylindrical structure with thin end plates is subjected to the harmonic point force at one end plate or both end plates, and a natural frequency of the end plates is selected as the forcing frequency. The resulting vibroacoustic coupling is then analyzed theoretically and experimentally by considering the dynamic behavior of the plates and the acoustic characteristics of the internal sound field as a function of the cylinder length. The length and phase difference between the plate vibrations, which maximize the sound pressure level inside the cavity, are clarified theoretically. The theoretical results are validated experimentally through an excitation experiment using an experimental apparatus that emulates the analytical model. Moreover, the electricity generation experiment verifies that sufficient vibroacoustic coupling can be created for the adopted electricity generating system to be effective as an electric energy-harvesting device.

  7. DESIGN OF STRUCTURAL ELEMENTS IN THE EVENT OF THE PRE-SET RELIABILITY, REGULAR LOAD AND BEARING CAPACITY DISTRIBUTION

    Directory of Open Access Journals (Sweden)

    Tamrazyan Ashot Georgievich

    2012-10-01

    Full Text Available Accurate and adequate description of external influences and of the bearing capacity of the structural material requires the employment of the probability theory methods. In this regard, the characteristic that describes the probability of failure-free operation is required. The characteristic of reliability means that the maximum stress caused by the action of the load will not exceed the bearing capacity. In this paper, the author presents a solution to the problem of calculation of structures, namely, the identification of reliability of pre-set design parameters, in particular, cross-sectional dimensions. If the load distribution pattern is available, employment of the regularities of distributed functions make it possible to find the pattern of distribution of maximum stresses over the structure. Similarly, we can proceed to the design of structures of pre-set rigidity, reliability and stability in the case of regular load distribution. We consider the element of design (a monolithic concrete slab, maximum stress S which depends linearly on load q. Within a pre-set period of time, the probability will not exceed the values according to the Poisson law. The analysis demonstrates that the variability of the bearing capacity produces a stronger effect on relative sizes of cross sections of a slab than the variability of loads. It is therefore particularly important to reduce the coefficient of variation of the load capacity. One of the methods contemplates the truncation of the bearing capacity distribution by pre-culling the construction material.

  8. Nano-level instrumentation for analyzing the dynamic accuracy of a rolling element bearing

    International Nuclear Information System (INIS)

    Yang, Z.; Hong, J.; Zhang, J.; Wang, M. Y.; Zhu, Y.

    2013-01-01

    The rotational performance of high-precision rolling bearings is fundamental to the overall accuracy of complex mechanical systems. A nano-level instrument to analyze rotational accuracy of high-precision bearings of machine tools under working conditions was developed. In this instrument, a high-precision (error motion < 0.15 μm) and high-stiffness (2600 N axial loading capacity) aerostatic spindle was applied to spin the test bearing. Operating conditions could be simulated effectively because of the large axial loading capacity. An air-cylinder, controlled by a proportional pressure regulator, was applied to drive an air-bearing subjected to non-contact and precise loaded axial forces. The measurement results on axial loading and rotation constraint with five remaining degrees of freedom were completely unconstrained and uninfluenced by the instrument's structure. Dual capacity displacement sensors with 10 nm resolution were applied to measure the error motion of the spindle using a double-probe error separation method. This enabled the separation of the spindle's error motion from the measurement results of the test bearing which were measured using two orthogonal laser displacement sensors with 5 nm resolution. Finally, a Lissajous figure was used to evaluate the non-repetitive run-out (NRRO) of the bearing at different axial forces and speeds. The measurement results at various axial loadings and speeds showed the standard deviations of the measurements’ repeatability and accuracy were less than 1% and 2%. Future studies will analyze the relationship between geometrical errors and NRRO, such as the ball diameter differences of and the geometrical errors in the grooves of rings

  9. Coupling nonlinear Stokes and Darcy flow using mortar finite elements

    KAUST Repository

    Ervin, Vincent J.; Jenkins, Eleanor W.; Sun, Shuyu

    2011-01-01

    We study a system composed of a nonlinear Stokes flow in one subdomain coupled with a nonlinear porous medium flow in another subdomain. Special attention is paid to the mathematical consequence of the shear-dependent fluid viscosity for the Stokes

  10. A DWT and SVM based method for rolling element bearing fault diagnosis and its comparison with Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Sunil Tyagi

    2017-04-01

    Full Text Available A classification technique using Support Vector Machine (SVM classifier for detection of rolling element bearing fault is presented here.  The SVM was fed from features that were extracted from of vibration signals obtained from experimental setup consisting of rotating driveline that was mounted on rolling element bearings which were run in normal and with artificially faults induced conditions. The time-domain vibration signals were divided into 40 segments and simple features such as peaks in time domain and spectrum along with statistical features such as standard deviation, skewness, kurtosis etc. were extracted. Effectiveness of SVM classifier was compared with the performance of Artificial Neural Network (ANN classifier and it was found that the performance of SVM classifier is superior to that of ANN. The effect of pre-processing of the vibration signal by Discreet Wavelet Transform (DWT prior to feature extraction is also studied and it is shown that pre-processing of vibration signal with DWT enhances the effectiveness of both ANN and SVM classifiers. It has been demonstrated from experiment results that performance of SVM classifier is better than ANN in detection of bearing condition and pre-processing the vibration signal with DWT improves the performance of SVM classifier.

  11. THCM Coupled Model for Hydrate-Bearing Sediments: Data Analysis and Design of New Field Experiments (Marine and Permafrost Settings)

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Marcelo J. [Texas A & M Univ., College Station, TX (United States); Santamarina, J. Carlos [King Abdullah Univ. of Science and Technology (Saudi Arabia)

    2017-02-14

    Gas hydrates are solid compounds made of water molecules clustered around low molecular weight gas molecules such as methane, hydrogen, and carbon dioxide. Methane hydrates form under pressure (P) and temperature (T) conditions that are common in sub-permafrost layers and in deep marine sediments. Stability conditions constrain the occurrence of gas hydrates to submarine sediments and permafrost regions. The amount of technically recoverable methane trapped in gas hydrate may exceed 104tcf. Gas hydrates are a potential energy resource, can contribute to climate change, and can cause large-scale seafloor instabilities. In addition, hydrate formation can be used for CO2 sequestration (also through CO2-CH4 replacement), and efficient geological storage seals. The experimental study of hydrate bearing sediments has been hindered by the very low solubility of methane in water (lab testing), and inherent sampling difficulties associated with depressurization and thermal changes during core extraction. This situation has prompted more decisive developments in numerical modeling in order to advance the current understanding of hydrate bearing sediments, and to investigate/optimize production strategies and implications. The goals of this research has been to addresses the complex thermo-hydro-chemo-mechanical THCM coupled phenomena in hydrate-bearing sediments, using a truly coupled numerical model that incorporates sound and proven constitutive relations, satisfies fundamental conservation principles. Analytical solutions aimed at verifying the proposed code have been proposed as well. These tools will allow to better analyze available data and to further enhance the current understanding of hydrate bearing sediments in view of future field experiments and the development of production technology.

  12. Development and validation of a new kind of coupling element for wheel-hub motors

    Science.gov (United States)

    Perekopskiy, Sergey; Kasper, Roland

    2018-05-01

    For the automotive industry, electric powered vehicles are becoming an increasingly relevant factor in the competition against climate change. Application of one special example - a wheel-hub motor, for electric powered vehicle can support this challenge. Patented slotless air gap winding invented at the chair of mechatronics of the Otto von Guericke University Magdeburg has great application potential in constantly growing e-mobility field, especially for wheel-hub motors based on this technology due to its advantages, such as a high gravimetric power density and high efficiency. However, advantages of this technology are decreased by its sensibility to the loads out of driving maneuvers by dimensional variations of air gap consistency. This article describes the development and validation of a coupling element for the designed wheel-hub motor. To find a suitable coupling concept first the assembly structure of the motor was analyzed and developed design of the coupling element was checked. Based on the geometry of the motor and wheel a detailed design of the coupling element was generated. The analytical approach for coupling element describes a potential of the possible loads on the coupling element. The FEM simulation of critical load cases for the coupling element validated results of the analytical approach.

  13. Application of powder metallurgy technique to produce improved bearing elements for cryogenic aerospace engine turbopumps

    Science.gov (United States)

    Moxson, V. S.; Moracz, D. J.; Bhat, B. N.; Dolan, F. J.; Thom, R.

    1987-01-01

    Traditionally, vacuum melted 440C stainless steel is used for high performance bearings for aerospace cryogenic systems where corrosion due to condensation is a major concern. For the Space Shuttle Main Engine (SSME), however, 440C performance in the high-pressure turbopumps has been marginal. A basic assumption of this study was that powder metallurgy, rather than cast/wrought, processing would provide the finest, most homogeneous bearing alloy structure. Preliminary testing of P/M alloys (hardness, corrosion resistance, wear resistance, fatigue resistance, and fracture toughness) was used to 'de-select' alloys which did perform as well as baseline 440C. Five out of eleven candidate materials (14-4/6V, X-405, MRC-2001, T-440V, and D-5) based on preliminary screening were selected for the actual rolling-sliding five-ball testing. The results of this test were compared with high-performance vacuum-melted M50 bearing steel. The results of the testing indicated outstanding performance of two P/M alloys, X-405 and MRC-2001, which eventually will be further evaluated by full-scale bearing testing.

  14. A strongly conservative finite element method for the coupling of Stokes and Darcy flow

    KAUST Repository

    Kanschat, G.; Riviè re, B.

    2010-01-01

    We consider a model of coupled free and porous media flow governed by Stokes and Darcy equations with the Beavers-Joseph-Saffman interface condition. This model is discretized using divergence-conforming finite elements for the velocities

  15. Elements of a compatible optimization theory for coupled systems

    International Nuclear Information System (INIS)

    Bonnemay, A.

    1969-01-01

    The first theory deals with the compatible optimization in coupled systems. A game theory for two players and with a non-zero sum is first developed. The conclusions are then extended to the case of a game with any finite number of players. After this essentially static study, the dynamic aspect of the problem is applied to the case of games which evolve. By applying PONTRYAGIN maximum principle it is possible to derive a compatible optimisation theorem which constitutes a necessary condition. (author) [fr

  16. Smoothness of running of large turbosets with particular regard to the coupling of rotor and foundation via slide bearings. Laufstabilitaet von grossen Turbosaetzen unter besonderer Beruecksichtigung der Kopplung von Rotor und Fundament ueber die Gleitlager

    Energy Technology Data Exchange (ETDEWEB)

    Bosin, D.

    1989-01-01

    Turboset operation is still faced with the unresolved problem of self-induced vibrations resulting from the hydrodynamic forces in the sliding bearings. In addition, more elastic supporting structures will result in a coupling of the vibration patterns of the rotor and foundations. These coupling mechanisms are investigated by the author. The stability calculation is carried out as follows: The equations of motion of the coupled overall system are established by a finite element method; the large number of degrees of freedom is condensed modally, and the specific eigenvalue problem is solved using the HQR algorithm. An iterative procedure, which is made necessary by the formulation of structural damping as viscous damping, determines the stability limit as the first 'zero run' of the real part of a complex eigenvalue. Eigenvalue tracking is possible if necessary. The application of the method to a medium-sized turboset and some parameter variations show that the stability limit will be changed significantly if the foundation is considered, depending on the degree of damping and the type of slide bearing. A realistic stability calculation should therefore be based on the coupled rotor/slide bearing/foundation model. (orig.) With 53 figs., 7 tabs.

  17. Application of blind deconvolution with crest factor for recovery of original rolling element bearing defect signals

    International Nuclear Information System (INIS)

    Son, J. D.; Yang, B. S.; Tan, A. C. C.; Mathew, J.

    2004-01-01

    Many machine failures are not detected well in advance due to the masking of background noise and attenuation of the source signal through the transmission mediums. Advanced signal processing techniques using adaptive filters and higher order statistics have been attempted to extract the source signal from the measured data at the machine surface. In this paper, blind deconvolution using the Eigenvector Algorithm (EVA) technique is used to recover a damaged bearing signal using only the measured signal at the machine surface. A damaged bearing signal corrupted by noise with varying signal-to-noise (s/n) was used to determine the effectiveness of the technique in detecting an incipient signal and the optimum choice of filter length. The results show that the technique is effective in detecting the source signal with an s/n ratio as low as 0.21, but requires a relatively large filter length

  18. Reevaluation of the stress-life relation in rolling-element bearings

    Science.gov (United States)

    Parker, R. J.; Zaretsky, E. V.

    1972-01-01

    Four groups of 12.7 millimeter diameter vacuum-degassed AISI 52100 balls were tested, each at a maximum Hertz stress in the range of 4.5 times 10 to 9th power to 6.0 times 10 to 9th power N/m2. Tests were run in the five-ball fatigue tester at a contact angle of 30 deg and a shaft speed of 10,000 rpm. The 10 percent fatigue lives at the four stress levels indicated that fatigue life is inversely proportional to maximum Hertz stress raised to the power of 12. This result agrees with a survey of the literature which suggests that a stress-life exponent of approximately 12 is typical of vacuum-processed bearing steels rather than the exponent of 9 which has been generally accepted by the bearing industry.

  19. Contribution of Italy to the activities on intercomparison of analysis methods for seismically isolated nuclear structures: Finite element analysis of lead rubber bearings

    International Nuclear Information System (INIS)

    Dusi, A.; Forni, M.; Martelli, A.

    1998-01-01

    This paper presents a summary of the results of nonlinear Finite Element (FE) analyses carried out by ENEL-Ricerca, Hydraulic and Structural Centre and ENEA-ERG-SIEC-SISM, on Lead Rubber Bearings (LRBs). Activities were carried out in the framework of the four years' Coordinated Research Programme (CRP) of the International Atomic Energy Agency (IAEA) on I ntercomparison of Analysis Methods for Seismically Isolated Nuclear Structures . The bearing Finite Element Models (FEMs) are validated through comparisons of the numerical results with experimental test data. The reliability of FEMs for simulating the behaviour of rubber bearings is presented and discussed. (author)

  20. Determination of rare earth elements in aluminum by inductively coupled plasma-atomic emission spectroscopy

    International Nuclear Information System (INIS)

    Mahanti, H.S.; Barnes, R.M.

    1983-01-01

    Inductively coupled plasma-atomic emission spectroscopy is evaluated for the determination of 14 rare earth elements in aluminum. Spectral line interference, limit of detection, and background equivalent concentration values are evaluated, and quantitative recovery is obtained from aluminum samples spiked with rare earth elements. The procedure is simple and suitable for routine process control analysis. 20 references, 5 tables

  1. Automatic Condition Monitoring of Industrial Rolling-Element Bearings Using Motor’s Vibration and Current Analysis

    Directory of Open Access Journals (Sweden)

    Zhenyu Yang

    2015-01-01

    Full Text Available An automatic condition monitoring for a class of industrial rolling-element bearings is developed based on the vibration as well as stator current analysis. The considered fault scenarios include a single-point defect, multiple-point defects, and a type of distributed defect. Motivated by the potential commercialization, the developed system is promoted mainly using off-the-shelf techniques, that is, the high-frequency resonance technique with envelope detection and the average of short-time Fourier transform. In order to test the flexibility and robustness, the monitoring performance is extensively studied under diverse operating conditions: different sensor locations, motor speeds, loading conditions, and data samples from different time segments. The experimental results showed the powerful capability of vibration analysis in the bearing point defect fault diagnosis. The current analysis also showed a moderate capability in diagnosis of point defect faults depending on the type of fault, severity of the fault, and the operational condition. The temporal feature indicated a feasibility to detect generalized roughness fault. The practical issues, such as deviations of predicted characteristic frequencies, sideband effects, time-average of spectra, and selection of fault index and thresholds, are also discussed. The experimental work shows a huge potential to use some simple methods for successful diagnosis of industrial bearing systems.

  2. The simulation of electrostatic coupling intra-body communication based on the finite-element method

    Institute of Scientific and Technical Information of China (English)

    Song Yong; Zhang Kai; Yang Guang; Zhu Kang; Hao Qun

    2011-01-01

    In this paper, investigation has been done in the computer simulation of the electrostatic coupling IBC by using the developed finite-element models, in which a. the incidence and reflection of electronic signal in the upper arm model were analyzed by using the theory of electromagnetic wave; b. the finite-element models of electrostatic coupling IBC were developed by using the electromagnetic analysis package of ANSYS software; c. the signal attenuation of electrostatic coupling IBC were simulated under the conditions of different signal frequencies, electrodes directions, electrodes sizes and transmission distances. Finally, some important conclusions are deduced on the basis of simulation results.

  3. Multi-elemental determination of trace elements in deep seawater by inductively coupled plasma mass spectrometry with resin preconcentration

    International Nuclear Information System (INIS)

    Sumida, Takashi; Nakazato, Tetsuya; Tao, Hiroaki

    2003-01-01

    A miniaturized column (ca. 3 mm i.d., 40 mm length), packed with a chelating resin (0.2 g) with iminodiacetic acid groups (Muromac A-1), was tested for the preconcentration of trace elements in seawater. After preconcentration, the column was washed with ammonium acetate buffer (pH 5.5) and water to remove the major elements, such as Ca and Mg, and was then eluted with 4 ml of 2 mol l -1 nitric acid. Twenty-six trace elements were determined by inductively coupled plasma mass spectrometry and inductively coupled plasma emission spectrometry. The necessary volume of the seawater sample was only 200 ml. The recoveries for most of the elements tested were over 90%, although those for Al, V and Th were around 70%. The trueness and precision were evaluated by analyzing a standard reference material of seawater (NASS-4, NRC Canada). The observed values obtained with the present method showed good agreement with the certified values. The present method was also applied to deep seawater samples collected at Muroto, Japan. A difference in the rare earth element pattern, especially the Ce anomaly, between the deep seawater sample and the surface seawater sample was observed, as well as the differences of the concentrations of many trace elements. (author)

  4. ACGT-containing abscisic acid response element (ABRE) and coupling element 3 (CE3) are functionally equivalent.

    Science.gov (United States)

    Hobo, T; Asada, M; Kowyama, Y; Hattori, T

    1999-09-01

    ACGT-containing ABA response elements (ABREs) have been functionally identified in the promoters of various genes. In addition, single copies of ABRE have been found to require a cis-acting, coupling element to achieve ABA induction. A coupling element 3 (CE3) sequence, originally identified as such in the barley HVA1 promoter, is found approximately 30 bp downstream of motif A (ACGT-containing ABRE) in the promoter of the Osem gene. The relationship between these two elements was further defined by linker-scan analyses of a 55 bp fragment of the Osem promoter, which is sufficient for ABA-responsiveness and VP1 activation. The analyses revealed that both motif A and CE3 sequence were required not only for ABA-responsiveness but also for VP1 activation. Since the sequences of motif A and CE3 were found to be similar, motif-exchange experiments were carried out. The experiments demonstrated that motif A and CE3 were interchangeable by each other with respect to both ABA and VP1 regulation. In addition, both sequences were shown to be recognized by a VP1-interacting, ABA-responsive bZIP factor TRAB1. These results indicate that ACGT-containing ABREs and CE3 are functionally equivalent cis-acting elements. Furthermore, TRAB1 was shown to bind two other non-ACGT ABREs. Based on these results, all these ABREs including CE3 are proposed to be categorized into a single class of cis-acting elements.

  5. Phylogenetic Conflict in Bears Identified by Automated Discovery of Transposable Element Insertions in Low-Coverage Genomes

    Science.gov (United States)

    Gallus, Susanne; Janke, Axel

    2017-01-01

    Abstract Phylogenetic reconstruction from transposable elements (TEs) offers an additional perspective to study evolutionary processes. However, detecting phylogenetically informative TE insertions requires tedious experimental work, limiting the power of phylogenetic inference. Here, we analyzed the genomes of seven bear species using high-throughput sequencing data to detect thousands of TE insertions. The newly developed pipeline for TE detection called TeddyPi (TE detection and discovery for Phylogenetic Inference) identified 150,513 high-quality TE insertions in the genomes of ursine and tremarctine bears. By integrating different TE insertion callers and using a stringent filtering approach, the TeddyPi pipeline produced highly reliable TE insertion calls, which were confirmed by extensive in vitro validation experiments. Analysis of single nucleotide substitutions in the flanking regions of the TEs shows that these substitutions correlate with the phylogenetic signal from the TE insertions. Our phylogenomic analyses show that TEs are a major driver of genomic variation in bears and enabled phylogenetic reconstruction of a well-resolved species tree, despite strong signals for incomplete lineage sorting and introgression. The analyses show that the Asiatic black, sun, and sloth bear form a monophyletic clade, in which phylogenetic incongruence originates from incomplete lineage sorting. TeddyPi is open source and can be adapted to various TE and structural variation callers. The pipeline makes it possible to confidently extract thousands of TE insertions even from low-coverage genomes (∼10×) of nonmodel organisms. This opens new possibilities for biologists to study phylogenies and evolutionary processes as well as rates and patterns of (retro-)transposition and structural variation. PMID:28985298

  6. Phylogenetic Conflict in Bears Identified by Automated Discovery of Transposable Element Insertions in Low-Coverage Genomes.

    Science.gov (United States)

    Lammers, Fritjof; Gallus, Susanne; Janke, Axel; Nilsson, Maria A

    2017-10-01

    Phylogenetic reconstruction from transposable elements (TEs) offers an additional perspective to study evolutionary processes. However, detecting phylogenetically informative TE insertions requires tedious experimental work, limiting the power of phylogenetic inference. Here, we analyzed the genomes of seven bear species using high-throughput sequencing data to detect thousands of TE insertions. The newly developed pipeline for TE detection called TeddyPi (TE detection and discovery for Phylogenetic Inference) identified 150,513 high-quality TE insertions in the genomes of ursine and tremarctine bears. By integrating different TE insertion callers and using a stringent filtering approach, the TeddyPi pipeline produced highly reliable TE insertion calls, which were confirmed by extensive in vitro validation experiments. Analysis of single nucleotide substitutions in the flanking regions of the TEs shows that these substitutions correlate with the phylogenetic signal from the TE insertions. Our phylogenomic analyses show that TEs are a major driver of genomic variation in bears and enabled phylogenetic reconstruction of a well-resolved species tree, despite strong signals for incomplete lineage sorting and introgression. The analyses show that the Asiatic black, sun, and sloth bear form a monophyletic clade, in which phylogenetic incongruence originates from incomplete lineage sorting. TeddyPi is open source and can be adapted to various TE and structural variation callers. The pipeline makes it possible to confidently extract thousands of TE insertions even from low-coverage genomes (∼10×) of nonmodel organisms. This opens new possibilities for biologists to study phylogenies and evolutionary processes as well as rates and patterns of (retro-)transposition and structural variation. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  7. Finite-element analysis of elastic sound-proof coupling thermal state

    Science.gov (United States)

    Tsyss, V. G.; Strokov, I. M.; Sergaeva, M. Yu

    2018-01-01

    The aim is in calculated determining of the elastic rubber-metal element thermal state of soundproof coupling ship shafting under variable influence during loads in time. Thermal coupling calculation is performed with finite element method using NX Simens software with Nastran solver. As a result of studies, the following results were obtained: - a volumetric picture of the temperature distribution over the array of the deformed coupling body is obtained; - time to reach steady-state thermal coupling mode has been determined; - dependences of maximum temperature and time to reach state on the established operation mode on rotation frequency and ambient temperature are determined. The findings prove the conclusion that usage of finite element analysis modern software can significantly speed up problem solving.

  8. Design and development of LH2 cooled rolling element radial bearings for the NERVA engine turbopump. Volume 3: Phase 2: Tests on build-ups 16, 17, and 18 at NRDS, Jackass Flats, Nevada, December 1971 - March 1972

    Science.gov (United States)

    Accinelli, J. B.; Koch, D. A.; Reuter, F.

    1972-01-01

    The use of liquid hydrogen to cool the rolling element radial bearings in the nuclear engine for rocket vehicles is discussed. The fifteen hour service life goal was obtained during the tests. The increase in bearing life was also considered to be produced by: (1) improvements in bearing material, (2) bearing retainer configuration and manufacturing changes, and (3) better control of operating parameters.

  9. Determination of rare earth elements in uranium bearing samples using Inductively Coupled Plasma Mass Spectrometry (ICPMS)

    International Nuclear Information System (INIS)

    Mishra, S.; Chaudhury, P.; Pradeepkumar, K.S.; Sahoo, S.K.

    2017-01-01

    In the present study a methodology has been described for determination of REEs without involving separation and the method is successfully applied for determination of REE concentration in uranium ore as well as in soil samples from a uranium mining site

  10. A Sparse Modulation Signal Bispectrum Analysis Method for Rolling Element Bearing Diagnosis

    Directory of Open Access Journals (Sweden)

    Guangbin Wang

    2018-01-01

    Full Text Available Modulation signal bispectrum (MSB analysis is an effective method to obtain the fault frequency for rolling bearing, but harmonics make fault frequency dense and even frequency aliasing. Carrier frequency of bearing is generally determined by its structure and inherent characteristics and changes with the increase of the damage degree, so it is hard to be accurately found. To solve these problems, this paper proposes a sparse modulation signal bispectrum analysis method. Firstly the vibration signal is demodulated by MSB analysis and its bispectrum is obtained. After the frequency domain filtering, the carrier frequency is computed based on the characteristics of energy concentration at the carrier frequency on MSB. By shift-frequency MSB (SF-MSB, the carrier frequency is moved to the coordinate origin, the entire MSB is shifted for the same distance, and SF-MSB is obtained. At last, the bispectrum is shifted to the frequency zero point and diagonal slices are performed to obtain a sparse representation of MSB. Experimental results show that sparse MSB (S-MSB method can not only eliminate the interference of harmonic frequency, but also make the extracted characteristic frequency of fault more obvious.

  11. Using Finite Element Method to Estimate the Material Properties of a Bearing Cage

    Science.gov (United States)

    2018-02-01

    result, a novel approach was developed to empirically test the phenolic cage and to determine the respective elastic and failure material properties...was available. As a result, a novel approach was developed to empirically test the phenolic cage and to determine the respective elastic and...was defeatured to decrease computing time, and the tooling was made rigid. The elements employed were 8-node brick elements with reduced integrations

  12. Computing Analysis of Bearing Elements of Launch Complex Aggregates for Space Rocket "Soyuz-2.1v"

    Directory of Open Access Journals (Sweden)

    V. A. Zverev

    2014-01-01

    Full Text Available The research is devoted to the computational analysis of bearing structures of launch system aggregates, which are designed for the prelaunch preparation and launch security of space rocket (SR "SOYUZ-2" of 1B stage. The bearing structures taken under consideration are the following: supporting trusses (ST, bearing arms (BA, the upper cable girder (UCG, the umbilical mast (UM. The SR “SOYUZ-2" of 1B stage has the characteristics of the propulsion unit (PU thrust, different from those of the "Soyuz" family space rockets exploited before.The paper presents basic modeling principles to calculate units and their operating loadings. The body self-weight and the influence of a gas-dynamic jet of "SOYUZ-2.1B" propulsion unit have been considered as a load of units. Parameters of this influence are determined on the basis of impulse stream fields and of deceleration temperatures calculated for various SR positions according to the specified path of its ascent and demolition.Physical models of the aggregates and calculations are based on the finite elements method and super-elements method using “SADAS” software package developed at the chair SM8 of Bauman Moscow State Technical University.Fields of nodal temperatures distribution in the ST, BA, UCG, UM models, and fields of tension in finite elements as well represent the calculation results.Obtained results revealed the most vulnerable of considered starting system aggregates, namely UM, which was taken for local durability calculation. As an example, this research considers calculation of local durability in the truss branches junction of UM rotary part, for which the constructive strengthening has been offered. For this node a detailed finite-element model built in the model of UM rotary part has been created. Calculation results of local durability testify that the strengthened node meets durability conditions.SR developers used calculation results of launch system aggregates for the space

  13. Finite element analysis of misaligned rotors on oil-film bearings

    Indian Academy of Sciences (India)

    (cylindrical, pocket, symmetrical three-lobed, unsymmetrical three-lobed). As a first step, the ... Yu & Adams (1989) discussed .... From the static load-deflection curve for a value of Sommerfeld number one finds out the ..... Sekhar A S, Prabhu B S 1995 Effects of coupling misalignment on vibrations of rotating machinery.

  14. Development and validation of a weight-bearing finite element model for total knee replacement.

    Science.gov (United States)

    Woiczinski, M; Steinbrück, A; Weber, P; Müller, P E; Jansson, V; Schröder, Ch

    2016-01-01

    Total knee arthroplasty (TKA) is a successful procedure for osteoarthritis. However, some patients (19%) do have pain after surgery. A finite element model was developed based on boundary conditions of a knee rig. A 3D-model of an anatomical full leg was generated from magnetic resonance image data and a total knee prosthesis was implanted without patella resurfacing. In the finite element model, a restarting procedure was programmed in order to hold the ground reaction force constant with an adapted quadriceps muscle force during a squat from 20° to 105° of flexion. Knee rig experimental data were used to validate the numerical model in the patellofemoral and femorotibial joint. Furthermore, sensitivity analyses of Young's modulus of the patella cartilage, posterior cruciate ligament (PCL) stiffness, and patella tendon origin were performed. Pearson's correlations for retropatellar contact area, pressure, patella flexion, and femorotibial ap-movement were near to 1. Lowest root mean square error for retropatellar pressure, patella flexion, and femorotibial ap-movement were found for the baseline model setup with Young's modulus of 5 MPa for patella cartilage, a downscaled PCL stiffness of 25% compared to the literature given value and an anatomical origin of the patella tendon. The results of the conducted finite element model are comparable with the experimental results. Therefore, the finite element model developed in this study can be used for further clinical investigations and will help to better understand the clinical aspects after TKA with an unresurfaced patella.

  15. Collective strong coupling with homogeneous Rabi frequencies using a 3D lumped element microwave resonator

    International Nuclear Information System (INIS)

    Angerer, Andreas; Astner, Thomas; Wirtitsch, Daniel; Majer, Johannes; Sumiya, Hitoshi; Onoda, Shinobu; Isoya, Junichi; Putz, Stefan

    2016-01-01

    We design and implement 3D-lumped element microwave cavities that spatially focus magnetic fields to a small mode volume. They allow coherent and uniform coupling to electron spins hosted by nitrogen vacancy centers in diamond. We achieve large homogeneous single spin coupling rates, with an enhancement of more than one order of magnitude compared to standard 3D cavities with a fundamental resonance at 3 GHz. Finite element simulations confirm that the magnetic field distribution is homogeneous throughout the entire sample volume, with a root mean square deviation of 1.54%. With a sample containing 10"1"7 nitrogen vacancy electron spins, we achieve a collective coupling strength of Ω = 12 MHz, a cooperativity factor C = 27, and clearly enter the strong coupling regime. This allows to interface a macroscopic spin ensemble with microwave circuits, and the homogeneous Rabi frequency paves the way to manipulate the full ensemble population in a coherent way.

  16. Coupled Analytical-Finite Element Methods for Linear Electromagnetic Actuator Analysis

    Directory of Open Access Journals (Sweden)

    K. Srairi

    2005-09-01

    Full Text Available In this paper, a linear electromagnetic actuator with moving parts is analyzed. The movement is considered through the modification of boundary conditions only using coupled analytical and finite element analysis. In order to evaluate the dynamic performance of the device, the coupling between electric, magnetic and mechanical phenomena is established. The displacement of the moving parts and the inductor current are determined when the device is supplied by capacitor discharge voltage.

  17. A multiscale finite element method for modeling fully coupled thermomechanical problems in solids

    KAUST Repository

    Sengupta, Arkaprabha; Papadopoulos, Panayiotis; Taylor, Robert L.

    2012-01-01

    This article proposes a two-scale formulation of fully coupled continuum thermomechanics using the finite element method at both scales. A monolithic approach is adopted in the solution of the momentum and energy equations. An efficient implementation of the resulting algorithm is derived that is suitable for multicore processing. The proposed method is applied with success to a strongly coupled problem involving shape-memory alloys. © 2012 John Wiley & Sons, Ltd.

  18. A multiscale finite element method for modeling fully coupled thermomechanical problems in solids

    KAUST Repository

    Sengupta, Arkaprabha

    2012-05-18

    This article proposes a two-scale formulation of fully coupled continuum thermomechanics using the finite element method at both scales. A monolithic approach is adopted in the solution of the momentum and energy equations. An efficient implementation of the resulting algorithm is derived that is suitable for multicore processing. The proposed method is applied with success to a strongly coupled problem involving shape-memory alloys. © 2012 John Wiley & Sons, Ltd.

  19. Coupling reduction between dipole antenna elements by using a planar meta-surface

    DEFF Research Database (Denmark)

    Saenz, Elena; Ederra, Inigo; Gonzalo, Ramon

    2009-01-01

    The mutual coupling between dipole antenna array elements using a planar meta-surface as superstrate is experimentally investigated. The meta-surface is based on grids of short metal strips and continuous wires. A comparison between the mutual coupling when the dipoles are radiating in free space...... driven dipole is fed and the others are matched with 50 Omega loads. The back-projected field on the aperture and on the E-plane is shown....

  20. Numerical modeling of the dynamic behavior of structures under impact with a discrete elements / finite elements coupling

    International Nuclear Information System (INIS)

    Rousseau, J.

    2009-07-01

    That study focuses on concrete structures submitted to impact loading and is aimed at predicting local damage in the vicinity of an impact zone as well as the global response of the structure. The Discrete Element Method (DEM) seems particularly well suited in this context for modeling fractures. An identification process of DEM material parameters from macroscopic data (Young's modulus, compressive and tensile strength, fracture energy, etc.) will first be presented for the purpose of enhancing reproducibility and reliability of the simulation results with DE samples of various sizes. Then, a particular interaction, between concrete and steel elements, was developed for the simulation of reinforced concrete. The discrete elements method was validated on quasi-static and dynamic tests carried out on small samples of concrete and reinforced concrete. Finally, discrete elements were used to simulate impacts on reinforced concrete slabs in order to confront the results with experimental tests. The modeling of a large structure by means of DEM may lead to prohibitive computation times. A refined discretization becomes required in the vicinity of the impact, while the structure may be modeled using a coarse FE mesh further from the impact area, where the material behaves elastically. A coupled discrete-finite element approach is thus proposed: the impact zone is modeled by means of DE and elastic FE are used on the rest of the structure. An existing method for 3D finite elements was extended to shells. This new method was then validated on many quasi-static and dynamic tests. The proposed approach is then applied to an impact on a concrete structure in order to validate the coupled method and compare computation times. (author)

  1. Analysis of transmission lines loaded with pairs of coupled resonant elements and application to sensors

    International Nuclear Information System (INIS)

    Naqui, J.; Su, L.; Mata, J.; Martín, F.

    2015-01-01

    This paper is focused on the analysis of transmission lines loaded with pairs of magnetically coupled resonators. We have considered two different structures: (i) a microstrip line loaded with pairs of stepped impedance resonators (SIRs), and (ii) a coplanar waveguide (CPW) transmission line loaded with pairs of split ring resonators (SRRs). In both cases, the line exhibits a single resonance frequency (transmission zero) if the resonators are identical (symmetric structure with regard to the line axis), and this resonance is different to the one of the line loaded with a single resonator due to inter-resonator coupling. If the structures are asymmetric, inter-resonator coupling enhances the distance between the two split resonance frequencies that arise. In spite that the considered lines and loading resonators are very different and are described by different lumped element equivalent circuit models, the phenomenology associated to the effects of coupling is exactly the same, and the resonance frequencies are given by identical expressions. The reported lumped element circuit models of both structures are validated by comparing the circuit simulations with extracted parameters with both electromagnetic simulations and experimental data. These structures can be useful for the implementation of microwave sensors based on symmetry properties. - Highlights: • Magnetic-coupling between resonant elements affects transmission properties. • Inter-resonant coupling enhances the distance of two resonant frequencies. • The structures are useful for sensors and comparators, etc

  2. Air-Coupled Ultrasonic Receivers with High Electromechanical Coupling PMN-32%PT Strip-Like Piezoelectric Elements

    Directory of Open Access Journals (Sweden)

    Rymantas J. Kazys

    2017-10-01

    Full Text Available For improvement of the efficiency of air-coupled ultrasonic transducers PMN-32%PT piezoelectric crystals which possess very high piezoelectric properties may be used. The electromechanical coupling factor of such crystals for all main vibration modes such as the thickness extension and transverse extension modes is more than 0.9. Operation of ultrasonic transducers with such piezoelectric elements in transmitting and receiving modes is rather different. Therefore, for transmission and reception of ultrasonic signals, separate piezoelectric elements with different dimensions must be used. The objective of this research was development of novel air-coupled ultrasonic receivers with PMN-32%PT strip-like piezoelectric elements vibrating in a transverse-extension mode with electromechanically controlled operation and suitable for applications in ultrasonic arrays. Performance of piezoelectric receivers made of the PMN-32%PT strip-like elements vibrating in this mode may be efficiently controlled by selecting geometry of the electrodes covering side surfaces of the piezoelectric element. It is equivalent to introduction of electromechanical damping which does not require any additional backing element. For this purpose; we have proposed the continuous electrodes to divide into two pairs of electrodes. The one pair is used to pick up the electric signal; another one is exploited for electromechanical damping. Two types of electrodes may be used—rectangular or non-rectangular—with a gap between them directed at some angle, usually 45°. The frequency bandwidth is wider (up to 9 kHz in the case of non-rectangular electrodes. The strip-like acoustic matching element bonded to the tip of the PMN-32%PT crystal may significantly enhance the performance of the ultrasonic receiver. It was proposed to use for this purpose AIREX T10.110 rigid polymer foam, the acoustic impedance of which is close to the optimal value necessary for matching with air. It was

  3. An efficient coupled polynomial interpolation scheme for shear mode sandwich beam finite element

    Directory of Open Access Journals (Sweden)

    Litesh N. Sulbhewar

    Full Text Available An efficient piezoelectric sandwich beam finite element is presented here. It employs the coupled polynomial field interpolation scheme for field variables which incorporates electromechanical coupling at interpolation level itself; unlike conventional sandwich beam theory (SBT based formulations available in the literature. A variational formulation is used to derive the governing equations, which are used to establish the relationships between field variables. These relations lead to the coupled polynomial field descriptions of variables, unlike conventional SBT formulations which use assumed independent polynomials. The relative axial displacement is expressed only by coupled terms containing contributions from other mechanical and electrical variables, thus eliminating use of the transverse displacement derivative as a degree of freedom. A set of coupled shape function based on these polynomials has shown the improvement in the convergence characteristics of the SBT based formulation. This improvement in the performance is achieved with one nodal degree of freedom lesser than the conventional SBT formulations.

  4. Determination of the contact stresses in double-row tapered roller bearings using the finite element method, experimental analysis and analytical models

    Energy Technology Data Exchange (ETDEWEB)

    Lostado, Ruben [University of La Rioja, Logroño (Spain); Martinez, Roberto Fernandez [University of Basque Country UPV/EHU, Bilbao (Spain); MacDonald, Bryan J. [Dublin City University, Dublin (Ireland)

    2015-11-15

    Double-row Tapered roller bearings (TRBs) are mechanical devices that are designed to support high axial, radial and torque loads. This combination of loads produces high contact stresses on the bearing raceways that are difficult to predict and validate experimentally, and can cause defects like pitting and fatigue spalling. In response, theoretical models have been proposed by many researchers to calculate the approximate distribution of contact stresses over the bearing raceways. More recently, numerical methods that are based on the Finite element method (FEM) have been used to obtain the contact stresses, although this method requires that the mesh size first be adjusted. This paper shows a process for adjusting a double-row TRB Finite element (FE) model. It is based on generating successive nonlinear FE submodels to calculate the distribution of contact stresses. A theoretical model and contact pressure sensors were used to adjust and validate the Finite element (FE) model.

  5. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  6. LIGHT-WEIGHT LOAD-BEARING STRUCTURES REINFORCED BY CORE ELEMENTS MADE OF SEGMENTS AND A METHOD OF CASTING SUCH STRUCTURES

    DEFF Research Database (Denmark)

    2009-01-01

    The invention relates to a light-weight load-bearing structure, reinforced by core elements (2) of a strong material constituting one or more compression or tension zones in the structure to be cast, which core (2) is surrounded by or adjacent to a material of less strength compared to the core (2......), where the core (2) is constructed from segments (1) of core elements (2) assembled by means of one or more prestressing elements (4). The invention further relates to a method of casting of light-weight load-bearing structures, reinforced by core elements (2) of a strong material constituting one...... or more compression or tension zones in the structure to be cast, which core (2) is surrounded by or adjacent to a material of less strength compared to the core (2), where the core (2) is constructed from segments (1) of core elements (2) assembled and hold together by means of one or more prestressing...

  7. Redox control of rotary motions in ferrocene-based elemental ball bearings.

    Science.gov (United States)

    Iordache, Adriana; Oltean, Mircea; Milet, Anne; Thomas, Fabrice; Baptiste, Benoît; Saint-Aman, Eric; Bucher, Christophe

    2012-02-08

    Rotational motions of ferrocene-based carousels have been achieved by electron transfer centered on π-dimerizable 4,4'-bipyridinium substituents introduced on both cyclopentadienyl rings through covalent linkers of different size, geometry, and flexibility. Detailed spectroscopic, electrochemical, and theoretical analyses demonstrate that rigid and fully conjugated linkers allow the quantitative formation of intramolecular π-dimers resulting from optimized orbital overlaps within the HOMO of the electrochemically generated bis-radical species. The tetra-cationic "charge-repelled" conformers, the self-assembled π-dimers, and their electron triggered interconversions have been investigated by UV-vis, NMR, and ESR spectroscopy, electrochemistry, X-ray diffraction analysis, and theoretical calculations. These studies support the conclusion that the rotation of both cyclopentadienyl rings in ferrocene can be controlled electrochemically using noncovalent reversible interactions arising from π-radical coupling processes.

  8. Trace and macro elements in the femoral bone as indicators of long-term environmental exposure to toxic metals in European brown bear (Ursus arctos) from Croatia.

    Science.gov (United States)

    Lazarus, Maja; Orct, Tatjana; Reljić, Slaven; Sedak, Marija; Bilandžić, Nina; Jurasović, Jasna; Huber, Đuro

    2018-05-21

    We explored the long-term accumulation of aluminium, strontium, cadmium and lead in the compact and trabecular bone of the femoral epiphysis, metaphysis and diaphysis in 41 brown bears (Ursus arctos) from Croatia. Also, we assessed their influence on macro and trace elements (sodium, magnesium, phosphorus, potassium, calcium, manganese, iron, cobalt, copper, zinc and barium) in bears' bone. There were no sex differences in element levels in general, while age was associated with bone length and levels of all elements, except for cadmium. Elements had different levels depending on the part of the bone sampled. More pronounced differences were observed between the compact and trabecular regions, with higher levels of majority of elements found in compact bone. Moderate to high associations (Spearman coefficient, r S  = 0.59-0.97) were confirmed between calcium and potassium, magnesium, phosphorus, manganese, cobalt, zinc, strontium and lead. Lead levels in the bone were below those known to cause adverse health effects, but in 4 of 41 animals they exceeded baseline levels for domestic animals. The femoral bone of the brown bear reflected the accumulative nature of lead and strontium well, as it did the impairment of bone-forming essential element levels associated with these two elements. However, the distribution pattern of elements along the bone was not uniform, so additional care should be taken when choosing on the part of the bone sampled.

  9. Improving torque per kilogram magnet of permanent magnet couplings using finite element analysis

    DEFF Research Database (Denmark)

    Högberg, Stig; Jensen, Bogi Bech; Bendixen, Flemming Buus

    2013-01-01

    This paper presents the methodology and subsequent findings of a performance-improvement routine that employs automated finite element (FE) analysis to increase the torque-per-kilogram-magnet (TPKM) of a permanent magnet coupling (PMC). The routine is applied to a commercially available cylindrical...

  10. Computer finite element analysis of stress derived from particular units of torsionally flexible metal coupling

    Directory of Open Access Journals (Sweden)

    Mariusz KUCZAJ

    2010-01-01

    Full Text Available In this article the results of Finite Element Analysis (FEA results of stresses derived from chosen units of torsionally flexible metal coupling are presented. As model and simulation tool for particular component loads is used the Autodesk Inventor Professional 2009 program.

  11. Multi-elemental analysis of aqueous geological samples by inductively coupled plasma-optical emission spectrometry

    Science.gov (United States)

    Todorov, Todor I.; Wolf, Ruth E.; Adams, Monique

    2014-01-01

    Typically, 27 major, minor, and trace elements are determined in natural waters, acid mine drainage, extraction fluids, and leachates of geological and environmental samples by inductively coupled plasma-optical emission spectrometry (ICP-OES). At the discretion of the analyst, additional elements may be determined after suitable method modifications and performance data are established. Samples are preserved in 1–2 percent nitric acid (HNO3) at sample collection or as soon as possible after collection. The aqueous samples are aspirated into the ICP-OES discharge, where the elemental emission signals are measured simultaneously for 27 elements. Calibration is performed with a series of matrix-matched, multi-element solution standards.

  12. Determination of rare earth elements by liquid chromatography/inductively coupled plasma atomic emission spectrometry

    International Nuclear Information System (INIS)

    Yoshida, K.; Haraguchi, H.

    1984-01-01

    Inductively coupled plasma atomic emission spectrometry (ICP-AES) interfaced with high-performance liquid chromatography (HPLC) has been applied to the determination of rare earth elements. ICP-AES was used as an element-selective detector for HPLC. The separation of rare earth elements with HPLC helped to avoid erroneous analytical results due to spectral interferences. Fifteen rare earth elements (Y and 14 lanthanides) were determined selectively with the HPLC/ICP-AES system using a concentration gradient method. The detection limits with the present HPLC/ICP-AES system were about 0.001-0.3 μg/mL with a 100-μL sample injection. The calibration curves obtained by the peak height measurements showed linear relationships in the concentration range below 500 μg/mL for all rare earth elements. A USGS rock standard sample, rare earth ores, and high-purity lanthanide reagents (>99.9%) were successfully analyzed without spectral interferences

  13. Chaos and bifurcation of a flexible rotor supported by porous squeeze couple stress fluid film journal bearings with non-linear suspension

    International Nuclear Information System (INIS)

    Chang-Jian, C.-W.; Chen, C.-K.

    2008-01-01

    This study presents a dynamic analysis of a flexible rotor supported by two porous squeeze couple stress fluid film journal bearings with non-linear suspension. The dynamics of the rotor center and bearing center are studied. The analysis of the rotor-bearing system is investigated under the assumptions of non-Newtonian fluid and a short bearing approximation. The spatial displacements in the horizontal and vertical directions are considered for various non-dimensional speed ratios. The dynamic equations are solved using the Runge-Kutta method. The analysis methods employed in this study is inclusive of the dynamic trajectories of the rotor center and bearing center, power spectra, Poincare maps and bifurcation diagrams. The maximum Lyapunov exponent analysis is also used to identify the onset of chaotic motion. The numerical results show that the stability of the system varies with the non-dimensional speed ratios, the non-dimensional parameter l* and the permeability. The modeling results thus obtained by using the method proposed in this paper can be employed to predict the stability of the rotor-bearing system and the undesirable behavior of the rotor and bearing center can be avoided

  14. Calculation of load-bearing capacity of prestressed reinforced concrete trusses by the finite element method

    Science.gov (United States)

    Agapov, Vladimir; Golovanov, Roman; Aidemirov, Kurban

    2017-10-01

    The technique of calculation of prestressed reinforced concrete trusses with taking into account geometrical and physical nonlinearity is considered. As a tool for solving the problem, the finite element method has been chosen. Basic design equations and methods for their solution are given. It is assumed that there are both a prestressed and nonprestressed reinforcement in the bars of the trusses. The prestress is modeled by setting the temperature effect on the reinforcement. The ways of taking into account the physical and geometrical nonlinearity for bars of reinforced concrete trusses are considered. An example of the analysis of a flat truss is given and the behavior of the truss on various stages of its loading up to destruction is analyzed. A program for the analysis of flat and spatial concrete trusses taking into account the nonlinear deformation is developed. The program is adapted to the computational complex PRINS. As a part of this complex it is available to a wide range of engineering, scientific and technical workers

  15. Analysis of a discrete element method and coupling with a compressible fluid flow method

    International Nuclear Information System (INIS)

    Monasse, L.

    2011-01-01

    This work aims at the numerical simulation of compressible fluid/deformable structure interactions. In particular, we have developed a partitioned coupling algorithm between a Finite Volume method for the compressible fluid and a Discrete Element method capable of taking into account fractures in the solid. A survey of existing fictitious domain methods and partitioned algorithms has led to choose an Embedded Boundary method and an explicit coupling scheme. We first showed that the Discrete Element method used for the solid yielded the correct macroscopic behaviour and that the symplectic time-integration scheme ensured the preservation of energy. We then developed an explicit coupling algorithm between a compressible inviscid fluid and an un-deformable solid. Mass, momentum and energy conservation and consistency properties were proved for the coupling scheme. The algorithm was then extended to the coupling with a deformable solid, in the form of a semi implicit scheme. Finally, we applied this method to unsteady inviscid flows around moving structures: comparisons with existing numerical and experimental results demonstrate the excellent accuracy of our method. (author) [fr

  16. [Study on the determination of 14 inorganic elements in coffee by inductively coupled plasma mass spectrometry].

    Science.gov (United States)

    Nie, Xi-Du; Fu, Liang

    2013-07-01

    Samples of coffee were digested by microwave digestion, and inorganic elements amounts of Na, Mg, P, Ca, Cr, Mn, Fe, Co, Cu, Zn, As, Se, Mo and Pb in sample solutions were determined by inductively coupled plasma mass spectrometry (ICP-MS). HNO3 + H2O2 was used to achieve the complete decomposition of the organic matrix in a closed-vessel microwave oven. The working parameters of the instrument were optimized. The results showed that the relative standard deviation (RSD) was less than 3.84% for all the elements, and the recovery was found to be 92.00% -106.52% by adding standard recovery experiment. This method was simple, sensitive and precise and can perform simultaneous multi-elements determination of coffee, which could satisfy the sample examination request and provide scientific rationale for determining inorganic elements of coffee.

  17. Multiscale Modeling of Blood Flow: Coupling Finite Elements with Smoothed Dissipative Particle Dynamics

    KAUST Repository

    Moreno Chaparro, Nicolas; Vignal, Philippe; Li, Jun; Calo, Victor M.

    2013-01-01

    A variational multi scale approach to model blood flow through arteries is proposed. A finite element discretization to represent the coarse scales (macro size), is coupled to smoothed dissipative particle dynamics that captures the fine scale features (micro scale). Blood is assumed to be incompressible, and flow is described through the Navier Stokes equation. The proposed cou- pling is tested with two benchmark problems, in fully coupled systems. Further refinements of the model can be incorporated in order to explicitly include blood constituents and non-Newtonian behavior. The suggested algorithm can be used with any particle-based method able to solve the Navier-Stokes equation.

  18. Parametric Design Optimization Of A Novel Permanent Magnet Coupling Using Finite Element Analysis

    DEFF Research Database (Denmark)

    Högberg, Stig; Mijatovic, Nenad; Holbøll, Joachim

    2014-01-01

    A parametric design optimization routine has been applied to a novel magnetic coupling with improved recyclability. Coupling designs are modeled in a 3-D finite element environ- ment, and evaluated by three design objectives: pull-out torque, torque density by magnet mass, and torque density...... by total mass. Magnet and outer core thicknesses are varied discretely, whereas outer dimensions and air-gap length are kept constant. Comparative trends as a function of pole number and dimensions are depicted. A compromise exist between the design objectives, in which favoring one might reduce the other...

  19. Multiscale Modeling of Blood Flow: Coupling Finite Elements with Smoothed Dissipative Particle Dynamics

    KAUST Repository

    Moreno Chaparro, Nicolas

    2013-06-01

    A variational multi scale approach to model blood flow through arteries is proposed. A finite element discretization to represent the coarse scales (macro size), is coupled to smoothed dissipative particle dynamics that captures the fine scale features (micro scale). Blood is assumed to be incompressible, and flow is described through the Navier Stokes equation. The proposed cou- pling is tested with two benchmark problems, in fully coupled systems. Further refinements of the model can be incorporated in order to explicitly include blood constituents and non-Newtonian behavior. The suggested algorithm can be used with any particle-based method able to solve the Navier-Stokes equation.

  20. Coupled porohyperelastic mass transport (PHEXPT) finite element models for soft tissues using ABAQUS.

    Science.gov (United States)

    Vande Geest, Jonathan P; Simon, B R; Rigby, Paul H; Newberg, Tyler P

    2011-04-01

    Finite element models (FEMs) including characteristic large deformations in highly nonlinear materials (hyperelasticity and coupled diffusive/convective transport of neutral mobile species) will allow quantitative study of in vivo tissues. Such FEMs will provide basic understanding of normal and pathological tissue responses and lead to optimization of local drug delivery strategies. We present a coupled porohyperelastic mass transport (PHEXPT) finite element approach developed using a commercially available ABAQUS finite element software. The PHEXPT transient simulations are based on sequential solution of the porohyperelastic (PHE) and mass transport (XPT) problems where an Eulerian PHE FEM is coupled to a Lagrangian XPT FEM using a custom-written FORTRAN program. The PHEXPT theoretical background is derived in the context of porous media transport theory and extended to ABAQUS finite element formulations. The essential assumptions needed in order to use ABAQUS are clearly identified in the derivation. Representative benchmark finite element simulations are provided along with analytical solutions (when appropriate). These simulations demonstrate the differences in transient and steady state responses including finite deformations, total stress, fluid pressure, relative fluid, and mobile species flux. A detailed description of important model considerations (e.g., material property functions and jump discontinuities at material interfaces) is also presented in the context of finite deformations. The ABAQUS-based PHEXPT approach enables the use of the available ABAQUS capabilities (interactive FEM mesh generation, finite element libraries, nonlinear material laws, pre- and postprocessing, etc.). PHEXPT FEMs can be used to simulate the transport of a relatively large neutral species (negligible osmotic fluid flux) in highly deformable hydrated soft tissues and tissue-engineered materials.

  1. Coupled Boundary and Finite Element Analysis of Vibration from Railway Tunnels

    DEFF Research Database (Denmark)

    Andersen, Lars; Jones, C.J.C.

    2006-01-01

    The analysis of vibration from railway tunnels is of growing interest as new and higher-speed railways are built under the ground to address the transport problems of growing modern urban areas around cities. Such analysis can be carried out using numerical methods but models and therefore comput...... body vibration (about 4 to 80 Hz). A coupled finite element and boundary element scheme is applied in both two and three dimensions. Two tunnel designs are considered: a cut-and-cover tunnel for a double track and a single-track tunnel dug with the New Austrian Tunnelling Method (NATM)....

  2. An Element Free Galerkin method for an elastoplastic coupled to damage analysis

    Directory of Open Access Journals (Sweden)

    Sendi Zohra

    2016-01-01

    Full Text Available In this work, a Meshless approach for nonlinear solid mechanics is developed based on the Element Free Galerkin method. Furthermore, Meshless is combined with an elastoplastic model coupled to ductile damage. The efficiency of the proposed methodology is evaluated through various numerical examples. Besides these, two-dimensional tensile tests under several boundary conditions were studied and solved by a Dynamic-Explicit resolution scheme. Finally, the results obtained from the numerical simulations are analyzed and critically compared with Finite Element Method results.

  3. Rolling Element Bearing Performance Degradation Assessment Using Variational Mode Decomposition and Gath-Geva Clustering Time Series Segmentation

    Directory of Open Access Journals (Sweden)

    Yaolong Li

    2017-01-01

    Full Text Available By focusing on the issue of rolling element bearing (REB performance degradation assessment (PDA, a solution based on variational mode decomposition (VMD and Gath-Geva clustering time series segmentation (GGCTSS has been proposed. VMD is a new decomposition method. Since it is different from the recursive decomposition method, for example, empirical mode decomposition (EMD, local mean decomposition (LMD, and local characteristic-scale decomposition (LCD, VMD needs a priori parameters. In this paper, we will propose a method to optimize the parameters in VMD, namely, the number of decomposition modes and moderate bandwidth constraint, based on genetic algorithm. Executing VMD with the acquired parameters, the BLIMFs are obtained. By taking the envelope of the BLIMFs, the sensitive BLIMFs are selected. And then we take the amplitude of the defect frequency (ADF as a degradative feature. To get the performance degradation assessment, we are going to use the method called Gath-Geva clustering time series segmentation. Afterwards, the method is carried out by two pieces of run-to-failure data. The results indicate that the extracted feature could depict the process of degradation precisely.

  4. Controlled Dissolution of Surface Layers for Elemental Analysis by Inductively Coupled Plasma-Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lorge, Susan Elizabeth [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Determining the composition of thin layers is increasingly important for a variety of industrial materials such as adhesives, coatings and microelectronics. Secondary ion mass spectrometry (SIMS), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES), glow discharge mass spectrometry (GDMS), and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) are some of the techniques that are currently employed for the direct analysis of the sample surface. Although these techniques do not suffer from the contamination problems that often plague sample dissolution studies, they do require matrix matched standards for quantification. Often, these standards are not readily available. Despite the costs of clean hoods, Teflon pipette tips and bottles, and pure acids, partial sample dissolution is the primary method used in the semiconductor industry to quantify surface impurities. Specifically, vapor phase decomposition (VPD) coupled to ICP-MS or total reflection x-ray fluorescence (TXRF) provides elemental information from the top most surface layers at detection sensitivities in the 107-1010atoms/cm2 range. The ability to quantify with standard solutions is a main advantage of these techniques. Li and Houk applied a VPD-like technique to steel. The signal ratio of trace element to matrix element was used for quantification. Although controlled dissolution concentrations determined for some of the dissolved elements agreed with the certified values, concentrations determined for refractory elements (Ti, Nb and Ta) were too low. LA-ICP-MS and scanning electron microscopy (SEM) measurements indicated that carbide grains distributed throughout the matrix were high in these refractory elements. These elements dissolved at a slower rate than the matrix element, Fe. If the analyte element is not removed at a rate similar to the matrix element a true

  5. Electricity Generation Characteristics of Energy-Harvesting System with Piezoelectric Element Using Mechanical-Acoustic Coupling

    Directory of Open Access Journals (Sweden)

    Hirotarou Tsuchiya

    2016-01-01

    Full Text Available This paper describes the electricity generation characteristics of a new energy-harvesting system with piezoelectric elements. The proposed system is composed of a rigid cylinder and thin plates at both ends. The piezoelectric elements are installed at the centers of both plates, and one side of each plate is subjected to a harmonic point force. In this system, vibration energy is converted into electrical energy via electromechanical coupling between the plate vibration and piezoelectric effect. In addition, the plate vibration excited by the point force induces a self-sustained vibration at the other plate via mechanical-acoustic coupling between the plate vibrations and an internal sound field into the cylindrical enclosure. Therefore, the electricity generation characteristics should be considered as an electromechanical-acoustic coupling problem. The characteristics are estimated theoretically and experimentally from the electric power in the electricity generation, the mechanical power supplied to the plate, and the electricity generation efficiency that is derived from the ratio of both power. In particular, the electricity generation efficiency is one of the most appropriate factors to evaluate a performance of electricity generation systems. Thus, the effect of mechanical-acoustic coupling is principally evaluated by examining the electricity generation efficiency.

  6. Sensitivity of Particle Size in Discrete Element Method to Particle Gas Method (DEM_PGM) Coupling in Underbody Blast Simulations

    Science.gov (United States)

    2016-06-12

    Particle Size in Discrete Element Method to Particle Gas Method (DEM_PGM) Coupling in Underbody Blast Simulations Venkatesh Babu, Kumar Kulkarni, Sanjay...buried in soil viz., (1) coupled discrete element & particle gas methods (DEM-PGM) and (2) Arbitrary Lagrangian-Eulerian (ALE), are investigated. The...DEM_PGM and identify the limitations/strengths compared to the ALE method. Discrete Element Method (DEM) can model individual particle directly, and

  7. Influence of Installation Effects on Pile Bearing Capacity in Cohesive Soils - Large Deformation Analysis Via Finite Element Method

    Science.gov (United States)

    Konkol, Jakub; Bałachowski, Lech

    2017-03-01

    In this paper, the whole process of pile construction and performance during loading is modelled via large deformation finite element methods such as Coupled Eulerian Lagrangian (CEL) and Updated Lagrangian (UL). Numerical study consists of installation process, consolidation phase and following pile static load test (SLT). The Poznań site is chosen as the reference location for the numerical analysis, where series of pile SLTs have been performed in highly overconsolidated clay (OCR ≈ 12). The results of numerical analysis are compared with corresponding field tests and with so-called "wish-in-place" numerical model of pile, where no installation effects are taken into account. The advantages of using large deformation numerical analysis are presented and its application to the pile designing is shown.

  8. Influence of Installation Effects on Pile Bearing Capacity in Cohesive Soils – Large Deformation Analysis Via Finite Element Method

    Directory of Open Access Journals (Sweden)

    Konkol Jakub

    2017-03-01

    Full Text Available In this paper, the whole process of pile construction and performance during loading is modelled via large deformation finite element methods such as Coupled Eulerian Lagrangian (CEL and Updated Lagrangian (UL. Numerical study consists of installation process, consolidation phase and following pile static load test (SLT. The Poznań site is chosen as the reference location for the numerical analysis, where series of pile SLTs have been performed in highly overconsolidated clay (OCR ≈ 12. The results of numerical analysis are compared with corresponding field tests and with so-called “wish-in-place” numerical model of pile, where no installation effects are taken into account. The advantages of using large deformation numerical analysis are presented and its application to the pile designing is shown.

  9. Spatial and temporal trends of selected trace elements in liver tissue from polar bears (Ursus maritimus) from Alaska, Canada and Greenland

    Science.gov (United States)

    Routti, H.; Letcher, R.J.; Born, E.W.; Branigan, M.; Dietz, R.; Evans, T.J.; Fisk, A.T.; Peacock, E.; Sonne, C.

    2011-01-01

    Spatial trends and comparative changes in time of selected trace elements were studied in liver tissue from polar bears from ten different subpopulation locations in Alaska, Canadian Arctic and East Greenland. For nine of the trace elements (As, Cd, Cu, Hg, Mn, Pb, Rb, Se and Zn) spatial trends were investigated in 136 specimens sampled during 2005-2008 from bears from these ten subpopulations. Concentrations of Hg, Se and As were highest in the (northern and southern) Beaufort Sea area and lowest in (western and southern) Hudson Bay area and Chukchi/Bering Sea. In contrast, concentrations of Cd showed an increasing trend from east to west. Minor or no spatial trends were observed for Cu, Mn, Rb and Zn. Spatial trends were in agreement with previous studies, possibly explained by natural phenomena. To assess temporal changes of Cd, Hg, Se and Zn concentrations during the last decades, we compared our results to previously published data. These time comparisons suggested recent Hg increase in East Greenland polar bears. This may be related to Hg emissions and/or climate-induced changes in Hg cycles or changes in the polar bear food web related to global warming. Also, Hg:Se molar ratio has increased in East Greenland polar bears, which suggests there may be an increased risk for Hg 2+-mediated toxicity. Since the underlying reasons for spatial trends or changes in time of trace elements in the Arctic are still largely unknown, future studies should focus on the role of changing climate and trace metal emissions on geographical and temporal trends of trace elements. ?? 2011 The Royal Society of Chemistry.

  10. Spatial and temporal trends of selected trace elements in liver tissue from polar bears (Ursus maritimus) from Alaska, Canada and Greenland.

    Science.gov (United States)

    Routti, Heli; Letcher, Robert J; Born, Erik W; Branigan, Marsha; Dietz, Rune; Evans, Thomas J; Fisk, Aaron T; Peacock, Elizabeth; Sonne, Christian

    2011-08-01

    Spatial trends and comparative changes in time of selected trace elements were studied in liver tissue from polar bears from ten different subpopulation locations in Alaska, Canadian Arctic and East Greenland. For nine of the trace elements (As, Cd, Cu, Hg, Mn, Pb, Rb, Se and Zn) spatial trends were investigated in 136 specimens sampled during 2005-2008 from bears from these ten subpopulations. Concentrations of Hg, Se and As were highest in the (northern and southern) Beaufort Sea area and lowest in (western and southern) Hudson Bay area and Chukchi/Bering Sea. In contrast, concentrations of Cd showed an increasing trend from east to west. Minor or no spatial trends were observed for Cu, Mn, Rb and Zn. Spatial trends were in agreement with previous studies, possibly explained by natural phenomena. To assess temporal changes of Cd, Hg, Se and Zn concentrations during the last decades, we compared our results to previously published data. These time comparisons suggested recent Hg increase in East Greenland polar bears. This may be related to Hg emissions and/or climate-induced changes in Hg cycles or changes in the polar bear food web related to global warming. Also, Hg:Se molar ratio has increased in East Greenland polar bears, which suggests there may be an increased risk for Hg(2+)-mediated toxicity. Since the underlying reasons for spatial trends or changes in time of trace elements in the Arctic are still largely unknown, future studies should focus on the role of changing climate and trace metal emissions on geographical and temporal trends of trace elements.

  11. Levels of Essential Elements in Different Medicinal Plants Determined by Using Inductively Coupled Plasma Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Eid I. Brima

    2018-01-01

    Full Text Available The objective of this study was to investigate the content of essential elements in medicinal plants in the Kingdom of Saudi Arabia (KSA. Five different medical plants (mahareeb (Cymbopogon schoenanthus, sheeh (Artemisia vulgaris, harjal (Cynanchum argel delile, nabipoot (Equisetum arvense, and cafmariam (Vitex agnus-castus were collected from Madina city in the KSA. Five elements Fe, Mn, Zn, Cu, and Se were determined by using inductively coupled plasma mass spectrometry (ICP-MS. Fe levels were the highest and Se levels were the lowest in all plants. The range levels of all elements in all plants were as follows: Fe 193.4–1757.9, Mn 23.6–143.7, Zn 15.4–32.7, Se 0.13–0.92, and Cu 11.3–21.8 µg/g. Intakes of essential elements from the medical plants in infusion were calculated: Fe 4.6–13.4, Mn 6.7–123.2, Zn 7.0–42.7, Se 0.14–1.5, and Cu 1.5–5.0 µg/dose. The calculated intakes of essential elements for all plants did not exceed the daily intake set by the World Health Organization (WHO and European Food Safety Authority (EFSA. These medicinal plants may be useful sources of essential elements, which are vital for health.

  12. Coupled thermomechanical behavior of graphene using the spring-based finite element approach

    Energy Technology Data Exchange (ETDEWEB)

    Georgantzinos, S. K., E-mail: sgeor@mech.upatras.gr; Anifantis, N. K., E-mail: nanif@mech.upatras.gr [Machine Design Laboratory, Department of Mechanical Engineering and Aeronautics, University of Patras, Rio, 26500 Patras (Greece); Giannopoulos, G. I., E-mail: ggiannopoulos@teiwest.gr [Materials Science Laboratory, Department of Mechanical Engineering, Technological Educational Institute of Western Greece, 1 Megalou Alexandrou Street, 26334 Patras (Greece)

    2016-07-07

    The prediction of the thermomechanical behavior of graphene using a new coupled thermomechanical spring-based finite element approach is the aim of this work. Graphene sheets are modeled in nanoscale according to their atomistic structure. Based on molecular theory, the potential energy is defined as a function of temperature, describing the interatomic interactions in different temperature environments. The force field is approached by suitable straight spring finite elements. Springs simulate the interatomic interactions and interconnect nodes located at the atomic positions. Their stiffness matrix is expressed as a function of temperature. By using appropriate boundary conditions, various different graphene configurations are analyzed and their thermo-mechanical response is approached using conventional finite element procedures. A complete parametric study with respect to the geometric characteristics of graphene is performed, and the temperature dependency of the elastic material properties is finally predicted. Comparisons with available published works found in the literature demonstrate the accuracy of the proposed method.

  13. Multiscale Simulations for Coupled Flow and Transport Using the Generalized Multiscale Finite Element Method

    KAUST Repository

    Chung, Eric

    2015-12-11

    In this paper, we develop a mass conservative multiscale method for coupled flow and transport in heterogeneous porous media. We consider a coupled system consisting of a convection-dominated transport equation and a flow equation. We construct a coarse grid solver based on the Generalized Multiscale Finite Element Method (GMsFEM) for a coupled system. In particular, multiscale basis functions are constructed based on some snapshot spaces for the pressure and the concentration equations and some local spectral decompositions in the snapshot spaces. The resulting approach uses a few multiscale basis functions in each coarse block (for both the pressure and the concentration) to solve the coupled system. We use the mixed framework, which allows mass conservation. Our main contributions are: (1) the development of a mass conservative GMsFEM for the coupled flow and transport; (2) the development of a robust multiscale method for convection-dominated transport problems by choosing appropriate test and trial spaces within Petrov-Galerkin mixed formulation. We present numerical results and consider several heterogeneous permeability fields. Our numerical results show that with only a few basis functions per coarse block, we can achieve a good approximation.

  14. Multiscale Simulations for Coupled Flow and Transport Using the Generalized Multiscale Finite Element Method

    KAUST Repository

    Chung, Eric; Efendiev, Yalchin R.; Leung, Wing; Ren, Jun

    2015-01-01

    In this paper, we develop a mass conservative multiscale method for coupled flow and transport in heterogeneous porous media. We consider a coupled system consisting of a convection-dominated transport equation and a flow equation. We construct a coarse grid solver based on the Generalized Multiscale Finite Element Method (GMsFEM) for a coupled system. In particular, multiscale basis functions are constructed based on some snapshot spaces for the pressure and the concentration equations and some local spectral decompositions in the snapshot spaces. The resulting approach uses a few multiscale basis functions in each coarse block (for both the pressure and the concentration) to solve the coupled system. We use the mixed framework, which allows mass conservation. Our main contributions are: (1) the development of a mass conservative GMsFEM for the coupled flow and transport; (2) the development of a robust multiscale method for convection-dominated transport problems by choosing appropriate test and trial spaces within Petrov-Galerkin mixed formulation. We present numerical results and consider several heterogeneous permeability fields. Our numerical results show that with only a few basis functions per coarse block, we can achieve a good approximation.

  15. Cavitation Estimates by Orbit Prediction of a Journal Bearing - Finite Element Modelling and Experimental Studies Cavitation Estimates by Orbit Prediction of a Journal Bearing - Finite Element Modelling and Experimental Studies

    DEFF Research Database (Denmark)

    Christiansen, Christian Kim; Klit, Peder; Walther, Jens Honore

    2015-01-01

    The paper presents a two-sided approach to establish understanding of the cavitation phenomenon in dynamically loaded journal bearings, more specifically the engine bearings of large two-stroke marine diesel engines. One disadvantage of the journal bearing is the converging-diverging geometry....... Validation of the results is done against the Ruston and Hornsby 6VEB-X Mk III engine. Besides the numerical investigations a cavitation test rig has been developed. With this rig it is possible to generate cavitation under controlled conditions in terms ofload/eccentricity and rotational speed...

  16. Analysis of Trace Elements in Rat Bronchoalveolar Lavage Fluid by Inductively Coupled Plasma Mass Spectrometry.

    Science.gov (United States)

    Qamar, Wajhul; Al-Ghadeer, Abdul Rahman; Ali, Raisuddin; Abuelizz, Hatem A

    2017-08-01

    The main objective was to determine the elemental profile of the lung lining fluid of rats which are used as model animals in various experiments. Lung lining fluid elemental constitution obtained after bronchoalveolar lavage fluid (BALF) was analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to determine the biological trace elements along with calcium and magnesium. BALF was collected from healthy rats using a tracheal cannula. However, cells in BALF were counted to monitor any underlying inflammatory lung condition. Cell free BALF samples were processed and analyzed for the elements including magnesium (Mg), calcium (Ca), chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu), zinc (Zn), selenium (Se), bromine (Br), and iodine (I). In view of this, calcium concentration was the highest (6318.08 ± 3094.3 μg/L) and copper concentration was the lowest (0.89 ± 0.21 μg/L). The detected elements, from high to low concentration, include Ca > Mg > Fe > Br > I > Cr > Ni > Zn > Mn > Se > Cu. Pearson's correlation analysis revealed no significant correlation between cell count and concentration of any of the element detected in BALF. Correlation analysis also revealed significant positive correlation among Fe, I, Cr, Ni, and Mn. Ca was found to be correlated negatively with Cu and positively with Se. Br and Mg found to be positively correlated with each other. Zn remained the only element that was not found to be correlated with any of the elements in the rat BALF.

  17. Discrete element analysis of the mechanical properties of deep-sea methane hydrate-bearing soils considering interparticle bond thickness

    Science.gov (United States)

    Jiang, Mingjing; He, Jie; Wang, Jianfeng; Zhou, Yaping; Zhu, Fangyuan

    2017-12-01

    Due to increasing global energy demands, research is being conducted on the mechanical properties of methane hydrate-bearing soils (MHBSs), from which methane hydrate (MH) will be explored. This paper presents a numerical approach to study the mechanical properties of MHBSs. The relationship between the level of MH saturation and the interparticle bond thickness is first obtained by analyzing the scanning electron microscope images of MHBS samples, in which is the bridge connecting the micromechanical behavior captured by the DEM with the macroscopic properties of MHBSs. A simplified thermal-hydromechanical (THM) bond model that considers the different bond thicknesses is then proposed to describe the contact behavior between the soil particles and those incorporated into the discrete element method (DEM). Finally, a series of biaxial compression tests are carried out with different MH saturations under different effective confining pressures to analyze the mechanical properties of deep-sea MHBSs. The results of the DEM numerical simulation are also compared with the findings from triaxial compression tests. The results show that the macromechanical properties of deep-sea MHBSs can be qualitatively captured by the proposed DEM. The shear strength, cohesion, and volumetric contraction of deep-sea MHBSs increase with increasing MH saturation, although its influence on the internal friction angle is obscure. The shear strength and volumetric contraction increase with increasing effective confining pressure. The peak shear strength and the dilation of MHBSs increase as the critical bond thickness increases, while the residual deviator stress largely remains the same at a larger axial strain. With increasing the axial strain, the percentage of broken bonds increases, along with the expansion of the shear band.

  18. Enhanced efficacy of radiation-induced gene therapy in mice bearing lung adenocarcinoma xenografts using hypoxia responsive elements

    International Nuclear Information System (INIS)

    Wang Wei-dong; Chen Zheng-tang; Li De-zhi; Duan Yu-zhong; Cao Zheng-huai; Li Rong

    2005-01-01

    The aim of the present study was to investigate whether the hypoxia responsive element (HRE) could be used to enhance suicide gene (HSV-tk) expression and tumoricidal activity in radiation-controlled gene therapy of human lung adenocarcinoma xenografts. A chimeric promoter, HRE-Egr, was generated by directly linking a 0.3-kb fragment of HRE to a 0.6-kb human Egr-1 promoter. Retroviral vectors containing luciferase or the HSV-tk gene driven by Egr-1 or HRE-Egr were constructed. A human adenocarcinoma cell line (A549) was stably transfected with the above vectors using the lipofectamine method. The sensitivity of transfected cells to prodrug ganciclovir (GCV) and cell survival rates were analyzed after exposure to a dose of 2 Gy radiation and hypoxia (1%). In vivo, tumor xenografts in BALB/c mice were transfected with the constructed retroviruses and irradiated to a total dose of 6 Gy, followed by GCV treatment (20 mg/kg for 14 days). When the HSV-tk gene controlled by the HRE-Egr promoter was introduced into A549 cells by a retroviral vector, the exposure to 1% O 2 and 2 Gy radiation induced significant enhancement of GCV cytotoxicity to the cells. Moreover, in nude mice bearing solid tumor xenografts, only the tumors infected with the hybrid promoter-containing virus gradually disappeared after GCV administration and radiation. These results indicate that HRE can enhance transgene expression and tumoricidal activity in HSV-tk gene therapy controlled by ionizing radiation in hypoxic human lung adenocarcinoma. (author)

  19. Coupling finite elements and reliability methods - application to safety evaluation of pressurized water reactor vessels

    International Nuclear Information System (INIS)

    Pitner, P.; Venturini, V.

    1995-02-01

    When reliability studies are extended form deterministic calculations in mechanics, it is necessary to take into account input parameters variabilities which are linked to the different sources of uncertainty. Integrals must then be calculated to evaluate the failure risk. This can be performed either by simulation methods, or by approximations ones (FORM/SORM). Model in mechanics often require to perform calculation codes. These ones must then be coupled with the reliability calculations. Theses codes can involve large calculation times when they are invoked numerous times during simulations sequences or in complex iterative procedures. Response surface method gives an approximation of the real response from a reduced number of points for which the finite element code is run. Thus, when it is combined with FORM/SORM methods, a coupling can be carried out which gives results in a reasonable calculation time. An application of response surface method to mechanics reliability coupling for a mechanical model which calls for a finite element code is presented. It corresponds to a probabilistic fracture mechanics study of a pressurized water reactor vessel. (authors). 5 refs., 3 figs

  20. Finite Element Analysis of Mechanical Characteristics of Dropped Eggs Based on Fluid-Solid Coupling Theory

    Directory of Open Access Journals (Sweden)

    Song Haiyan

    2017-01-01

    Full Text Available It is important to study the properties and mechanics of egg drop impacts in order to reduce egg loss during processing and logistics and to provide a basis for the protective packaging of egg products. In this paper, we present the results of our study of the effects of the structural parameters on the mechanical properties of an egg using a finite element model of the egg. Based on Fluid-Solid coupling theory, a finite element model of an egg was constructed using ADINA, a finite element calculation and analysis software package. To simplify the model, the internal fluid of the egg was considered to be a homogeneous substance. The egg drop impact was simulated by the coupling solution, and the feasibility of the model was verified by comparison with the experimental results of a drop test. In summary, the modeling scheme was shown to be feasible and the simulation results provide a theoretical basis for the optimum design of egg packaging and egg processing equipment.

  1. Dynamic analysis of centrifugal machines rotors supported on ball bearings by combined application of 3D and beam finite element models

    Science.gov (United States)

    Pavlenko, I. V.; Simonovskiy, V. I.; Demianenko, M. M.

    2017-08-01

    This research paper is aimed to investigating rotor dynamics of multistage centrifugal machines with ball bearings by using the computer programs “Critical frequencies of the rotor” and “Forced oscillations of the rotor,” which are implemented the mathematical model based on the use of beam finite elements. Free and forces oscillations of the rotor for the multistage centrifugal oil pump NPS 200-700 are observed by taking into account the analytical dependence of bearing stiffness on rotor speed, which is previously defined on the basis of results’ approximation for the numerical simulation in ANSYS by applying 3D finite elements. The calculations found that characteristic and constrained oscillations of rotor and corresponded to them forms of vibrations, as well as the form of constrained oscillation on the actual frequency for acceptable residual unbalance are determined.

  2. Solution of problems with material nonlinearities with a coupled finite element/boundary element scheme using an iterative solver. Yucca Mountain Site Characterization Project

    International Nuclear Information System (INIS)

    Koteras, J.R.

    1996-01-01

    The prediction of stresses and displacements around tunnels buried deep within the earth is an important class of geomechanics problems. The material behavior immediately surrounding the tunnel is typically nonlinear. The surrounding mass, even if it is nonlinear, can usually be characterized by a simple linear elastic model. The finite element method is best suited for modeling nonlinear materials of limited volume, while the boundary element method is well suited for modeling large volumes of linear elastic material. A computational scheme that couples the finite element and boundary element methods would seem particularly useful for geomechanics problems. A variety of coupling schemes have been proposed, but they rely on direct solution methods. Direct solution techniques have large storage requirements that become cumbersome for large-scale three-dimensional problems. An alternative to direct solution methods is iterative solution techniques. A scheme has been developed for coupling the finite element and boundary element methods that uses an iterative solution method. This report shows that this coupling scheme is valid for problems where nonlinear material behavior occurs in the finite element region

  3. Coupled electromagnetic and structural finite element analysis of a superconducting dipole model

    International Nuclear Information System (INIS)

    Hirtenfelder, F.

    1996-01-01

    Many devices contain parts that undergo motion due to electromagnetic forces. The motion causes the electromagnetic fields to change. Thus the electromagnetic fields must be computed along with the structural motion. In many cases the motion produced by electromagnetic forces is desired motion. However, in many devices, some undesired motion can occur due to electromagnetic forces. The motion creases motion-induced eddy currents which in turn affect the electromagnetic fields and forces. A finite element technique is described that fully couples structural and electromagnetic analysis in the time domain. The code is applied to a superconducting dipole model in order to study deformations and stresses during ramp and quench. The results of this coupled analysis enables the designer to visualize deformations, vibrations, displacements and all electromagnetic field quantities of the device and to try different solutions to enhance its performance

  4. Galvanic coupling effects for module-mounting elements of ground-mounted photovoltaic power station

    Directory of Open Access Journals (Sweden)

    Pierozynski Boguslaw

    2017-12-01

    Full Text Available This communication reports on the concerns associated with possible generation of galvanic coupling effects for construction materials that are used to manufacture mounting assemblies for ground-mounted photovoltaic (PV power stations. For this purpose, six macro-corrosion galvanic cells were assembled, including: hot-dip Zn/Magnelis®-coated steel/Al and stainless steel (SS/Al cells. Corrosion experiments involved continuous, ca. three-month exposure of these couplings in 3 wt.% NaCl solution, conducted at room temperature for a stable pH value of around 8. All corrosion cells were subjected to regular assessment of galvanic current-density and potential parameters, where special consideration was given to compare the corrosion behaviour of Zn-coated steel samples with that of Magnelis®-coated electrodes. Characterization of surface condition and elemental composition for examined materials was carried-out by means of SEM and EDX spectroscopy techniques.

  5. Finite Element Analysis of Biot’s Consolidation with a Coupled Nonlinear Flow Model

    Directory of Open Access Journals (Sweden)

    Yue-bao Deng

    2016-01-01

    Full Text Available A nonlinear flow relationship, which assumes that the fluid flow in the soil skeleton obeys the Hansbo non-Darcian flow and that the coefficient of permeability changes with void ratio, was incorporated into Biot’s general consolidation theory for a consolidation simulation of normally consolidated soft ground with or without vertical drains. The governing equations with the coupled nonlinear flow model were presented first for the force equilibrium condition and then for the continuity condition. Based on the weighted residual method, the finite element (FE formulations were then derived, and an existing FE program was modified accordingly to take the nonlinear flow model into consideration. Comparative analyses using established theoretical solutions and numerical solutions were completed, and the results were satisfactory. On this basis, we investigated the effect of the coupled nonlinear flow on consolidation development.

  6. Determination of rare earth elements in tomato plants by inductively coupled plasma mass spectrometry techniques.

    Science.gov (United States)

    Spalla, S; Baffi, C; Barbante, C; Turetta, C; Turretta, C; Cozzi, G; Beone, G M; Bettinelli, M

    2009-10-30

    In recent years identification of the geographical origin of food has grown more important as consumers have become interested in knowing the provenance of the food that they purchase and eat. Certification schemes and labels have thus been developed to protect consumers and genuine producers from the improper use of popular brand names or renowned geographical origins. As the tomato is one of the major components of what is considered to be the healthy Mediterranean diet, it is important to be able to determine the geographical origin of tomatoes and tomato-based products such as tomato sauce. The aim of this work is to develop an analytical method to determine rare earth elements (RRE) for the control of the geographic origin of tomatoes. The content of REE in tomato plant samples collected from an agricultural area in Piacenza, Italy, was determined, using four different digestion procedures with and without HF. Microwave dissolution with HNO3 + H2O2 proved to be the most suitable digestion procedure. Inductively coupled plasma quadrupole mass spectrometry (ICPQMS) and inductively coupled plasma sector field plasma mass spectrometry (ICPSFMS) instruments, both coupled with a desolvation system, were used to determine the REE in tomato plants in two different laboratories. A matched calibration curve method was used for the quantification of the analytes. The detection limits (MDLs) of the method ranged from 0.03 ng g(-1) for Ho, Tm, and Lu to 2 ng g(-1) for La and Ce. The precision, in terms of relative standard deviation on six replicates, was good, with values ranging, on average, from 6.0% for LREE (light rare earth elements) to 16.5% for HREE (heavy rare earth elements). These detection limits allowed the determination of the very low concentrations of REE present in tomato berries. For the concentrations of REE in tomato plants, the following trend was observed: roots > leaves > stems > berries. Copyright 2009 John Wiley & Sons, Ltd.

  7. NAMMU: finite element program for coupled heat and groundwater flow problems

    International Nuclear Information System (INIS)

    Rae, J.; Robinson, P.C.

    1979-11-01

    NAMMU is a computer program which will calculate the evolution in time of coupled water and heat flow in a porous medium. It is intended to be used primarily for modelling studies of underground nuclear waste repositories. NAMMU is based on the Galerkin-Finite-element method and has self-adjusting time stepping. The present version is written for 2-dimensional cartesian or cylindrical coordinate systems. It has been checked against two calculations from the KBS study and an exact solution by Hodgkinson for a very idealised repository design. (author)

  8. A strongly conservative finite element method for the coupling of Stokes and Darcy flow

    KAUST Repository

    Kanschat, G.

    2010-08-01

    We consider a model of coupled free and porous media flow governed by Stokes and Darcy equations with the Beavers-Joseph-Saffman interface condition. This model is discretized using divergence-conforming finite elements for the velocities in the whole domain. Discontinuous Galerkin techniques and mixed methods are used in the Stokes and Darcy subdomains, respectively. This discretization is strongly conservative in Hdiv(Ω) and we show convergence. Numerical results validate our findings and indicate optimal convergence orders. © 2010 Elsevier Inc.

  9. Determination of Rare Earth Elements in Thai Monazite by Inductively Coupled Plasma and Nuclear Analytical techniques

    International Nuclear Information System (INIS)

    Busamongkol, Arporn; Ratanapra, Dusadee; Sukharn, Sumalee; Laoharojanaphand, Sirinart

    2003-10-01

    The inductively coupled plasma atomic emission spectroscopy (ICP-AES) for the determination of individual rare-earth elements (REE) was evaluated by comparison with instrumental neutron activation analysis (INAA) and x-ray fluorescence spectrometry (XRF). The accuracy and precision of INAA and ICP-AES were evaluated by using standard reference material IGS-36, a monazite concentrate. For INAA, the results were close to the certified value while ICP-AES were in good agreement except for some low concentration rare earth. The techniques were applied for the analysis of some rare earth elements in two Thai monazite samples preparing as the in-house reference material for the Rare Earth Research and Development Center, Chemistry Division, Office of Atoms for Peace. The analytical results obtained by these techniques were in good agreement with each other

  10. Mechanical strength calculation of the disk type windings with elastic couplings by the finite element method

    International Nuclear Information System (INIS)

    Sivkova, G.N.; Spirchenko, Yu.V.; Chvartatskij, P.V.

    1981-01-01

    Stressed-deformed state of toroidal field coils of the disc type with elastic couplings of the tokamaks has been investigated with provision for the effect of the central core pliability by means of the two-dimensional version of the finite element method. Numerical solution of the finite element method is performed by means of the ES 1040 computer according to the computer code permitting taking account of boundary conditions of elastic support. The calculation has been performed using as the example the project of T-20 facility coil of the disc type. Consideration of pliability of the central core of the facility inductor is accomplished by the introduction of additional rigidities to the complete matrix of rigidity. Scheme of the structure distretization includes 141 units, 211 elements. The accuracy of solution depends on the reduction accuracy of the volume load to unit forces and on the number of finite elements. Analysis of the solution convergence is performed by the comparison of solutions obtained for three different schemes of the disk discretization without regard for the inductor pliability. The comparative analysis of the results shows that transfer epures for all the three discretization versions practically coincide and stresses differ not more than by 10%. On the whole the above investigation has demonstrated good convergence of the problem solution [ru

  11. Study of gap conductance model for thermo mechanical fully coupled finite element model

    International Nuclear Information System (INIS)

    Kim, Hyo Cha; Yang, Yong Sik; Kim, Dae Ho; Bang, Je Geon; Kim, Sun Ki; Koo, Yang Hyun

    2012-01-01

    A light water reactor (LWR) fuel rod consists of zirconium alloy cladding and uranium dioxide pellets, with a slight gap between them. Therefore, the mechanical integrity of zirconium alloy cladding is the most critical issue, as it is an important barrier for fission products released into the environment. To evaluate the stress and strain of the cladding during operation, fuel performance codes with a one-dimensional (1D) approach have been reported since the 1970s. However, it is difficult for a 1D model to simulate the stress and strain of the cladding accurately owing to a lack of degree of freedom. A LWR fuel performance code should include thermo-mechanical coupled model owing to the existence of the fuel-cladding gap. Generally, the gap that is filled with helium gas results in temperature drop along radius direction. The gap conductance that determines temperature gradient within the gap is very sensitive to gap thickness. For instance, once the gap size increases up to several microns in certain region, difference of surface temperatures increases up to 100 Kelvin. Therefore, iterative thermo-mechanical coupled analysis is required to solve temperature distribution throughout pellet and cladding. Consequently, the Finite Element (FE) module, which can simulate a higher degree of freedom numerically, is an indispensable requirement to understand the thermomechanical behavior of cladding. FRAPCON-3, which is reliable performance code, has iterative loop for thermo-mechanical coupled calculation to solve 1D gap conductance model. In FEMAXI-III, 1D thermal analysis module and FE module for stress-strain analysis were separated. 1D thermal module includes iterative analysis between them. DIONISIO code focused on thermal contact model as function of surface roughness and contact pressure when the gap is closed. In previous works, gap conductance model has been developed only for 1D model or hybrid model (1D and FE). To simulate temperature, stress and strain

  12. Multielement determination of rare earth elements in rock sample by liquid chromatography / inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Hamanaka, Tadashi; Itoh, Akihide; Itoh, Shinya; Sawatari, Hideyuki; Haraguchi, Hiroki.

    1995-01-01

    Rare earth elements in geological standard rock sample JG-1 (granodiolite)issued from the Geological Survey of Japan have been determined by a combined system of liquid chromatography and inductively coupled plasma mass spectrometry. (author)

  13. An electromechanically coupled micro-sphere framework: application to the finite element analysis of electrostrictive polymers

    International Nuclear Information System (INIS)

    Thylander, Sara; Menzel, Andreas; Ristinmaa, Matti

    2012-01-01

    The number of industrial applications of electroactive polymers (EAPs) is increasing and, consequently, the need for reliable modelling frameworks for such materials as well as related robust simulation techniques continuously increases. In this context, we combine the modelling of non-linear electroelasticity with a computational micro-sphere formulation in order to simulate the behaviour of EAPs. The micro-sphere approach in general enables the use of physics-based constitutive models like, for instance, the so-called worm-like chain model. By means of the micro-sphere formulation, scalar-valued micromechanical constitutive relations can conveniently be extended to a three-dimensional continuum setting. We discuss several electromechanically coupled numerical examples and make use of the finite element method to solve inhomogeneous boundary value problems. The incorporated material parameters are referred to experimental data for an electrostrictive polymer. The numerical examples show that the coupled micro-sphere formulation combined with the finite element method results in physically sound simulations that mimic the behaviour of an electrostrictive polymer. (paper)

  14. Coupled Finite Volume and Finite Element Method Analysis of a Complex Large-Span Roof Structure

    Science.gov (United States)

    Szafran, J.; Juszczyk, K.; Kamiński, M.

    2017-12-01

    The main goal of this paper is to present coupled Computational Fluid Dynamics and structural analysis for the precise determination of wind impact on internal forces and deformations of structural elements of a longspan roof structure. The Finite Volume Method (FVM) serves for a solution of the fluid flow problem to model the air flow around the structure, whose results are applied in turn as the boundary tractions in the Finite Element Method problem structural solution for the linear elastostatics with small deformations. The first part is carried out with the use of ANSYS 15.0 computer system, whereas the FEM system Robot supports stress analysis in particular roof members. A comparison of the wind pressure distribution throughout the roof surface shows some differences with respect to that available in the engineering designing codes like Eurocode, which deserves separate further numerical studies. Coupling of these two separate numerical techniques appears to be promising in view of future computational models of stochastic nature in large scale structural systems due to the stochastic perturbation method.

  15. Identification of organically associated trace elements in wood and coal by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Richaud, R; Lazaro, M J; Lachas, H; Miller, B B; Herod, A A; Dugwell, D R; Kandiyoti, R

    2000-01-01

    1-Methyl-2-pyrrolidinone (NMP) was used to extract samples of wood (forest residue) and coal; the extracts were analysed by inductively coupled plasma mass spectrometry (ICP-MS) using two different sample preparation methods, in order to identify trace elements associated with the organic part of the samples. A sample of fly ash was similarly extracted and analysed in order to assess the behaviour of the mineral matter contained within the wood and coal samples. 32% of the biomass was extracted at the higher temperature and 12% at room temperature while only 12% of the coal was extracted at the higher temperature and 3% at room temperature. Less than 2% of the ash dissolved at the higher temperature. Size exclusion chromatograms of the extracts indicated the presence of significant amounts of large molecular mass materials (>1000 mu) in the biomass and coal extracts but not in the ash extract. Trace element analyses were carried out using ICP-MS on the acid digests prepared by 'wet ashing' and microwave extraction. Sixteen elements (As, Ba, Be, Cd, Co, Cr, Cu, Ga, Mn, Mo, Ni, Pb, Sb, Se, V and Zn) were quantified, in the samples before extraction, in the extracts and in the residues. Concentrations of trace elements in the original biomass sample were lower than in the coal sample while the concentrations in the ash sample were the highest. The major trace elements in the NMP extracts were Ba, Cu, Mn and Zn from the forest residue; Ba, Cu, Mn, Pb and Zn from the coal; Cu and Zn from the ash. These elements are believed to be associated with the organic extracts from the forest residue and coal, and also from the ash. Be and Sb were not quantified in the extracts because they were present at too low concentrations; up to 40% of Mn was extracted from the biomass sample at 202 degrees C, while Se was totally extracted from the ash sample. For the forest residue, approximately 7% (at room temperature) and 45% (at 202 degrees C) of the total trace elements studied were

  16. Finite element modeling of the electromechanical coupling in ionic polymer transducers

    Science.gov (United States)

    Akle, Barbar; Habchi, Wassim; Wallmersperger, Thomas; Leo, Donald

    2010-04-01

    Several researchers are actively studying Ionomeric polymer transducers (IPT) as a large strain low voltage Electro- Active Polymer (EAP) actuator. EAPs are devices that do not contain any moving parts leading to a potential large life time. Furthermore, they are light weight and flexible. An IPT is made of an ion saturated polymer usually Nafion, sandwiched between two electrodes made of a mixture of Nafion and electrically conductive particles usually RuO2 or platinum. Nafion is an acid membrane in which the cations are mobile while the anions are covalently fixed to the polymer structure. Upon the application of an electric potential on the order of 2V at the electrodes the mobile positive ions migrate towards the cathode leading to bending strains in the order of 5%. Our earlier studies demonstrate that the cations develop thin boundary layers around the electrode. Later developments in this finite element model captured the importance of adding particles in the electrode. This study presents the electromechanical coupling in ionic polymer transducers. Since all our earlier models were restricted to the electro-chemical part, here we will introduce the chemomechanical coupling. This coupling is performed based on previous studies (Akle and Leo) in which the authors experimentally showed that the mechanical strain in IPTs is proportional to a linear term and a quadratic term of the charge accumulated at the electrode. The values of the linear and quadratic terms are extracted from experimental data.

  17. Finite element modeling of a 3D coupled foot-boot model.

    Science.gov (United States)

    Qiu, Tian-Xia; Teo, Ee-Chon; Yan, Ya-Bo; Lei, Wei

    2011-12-01

    Increasingly, musculoskeletal models of the human body are used as powerful tools to study biological structures. The lower limb, and in particular the foot, is of interest because it is the primary physical interaction between the body and the environment during locomotion. The goal of this paper is to adopt the finite element (FE) modeling and analysis approaches to create a state-of-the-art 3D coupled foot-boot model for future studies on biomechanical investigation of stress injury mechanism, foot wear design and parachute landing fall simulation. In the modeling process, the foot-ankle model with lower leg was developed based on Computed Tomography (CT) images using ScanIP, Surfacer and ANSYS. Then, the boot was represented by assembling the FE models of upper, insole, midsole and outsole built based on the FE model of the foot-ankle, and finally the coupled foot-boot model was generated by putting together the models of the lower limb and boot. In this study, the FE model of foot and ankle was validated during balance standing. There was a good agreement in the overall patterns of predicted and measured plantar pressure distribution published in literature. The coupled foot-boot model will be fully validated in the subsequent works under both static and dynamic loading conditions for further studies on injuries investigation in military and sports, foot wear design and characteristics of parachute landing impact in military. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

  18. Coupling between a geochemical model and a transport model of dissolved elements

    International Nuclear Information System (INIS)

    Jacquier, P.

    1988-10-01

    In order to assess the safety analysis of an underground repository, the transport of radioelements in groundwater and their interactions with the geological medium are modelled. The objective of this work is the setting up and experimental validation of the coupling of a geochemical model with a transport model of dissolved elements. A laboratory experiment was developed at the CEA center of Cadarache. Flow-through experiments were carried out on columns filled with crushed limestone, where several inflow conditions were taken into account as the temperature, the presence of a pollutant (strontium chloride) at different concentrations. The results consist of the evolution of the chemical composition of the water at the outlet of the column. The final aim of the study is to explain these results with a coupled model where geochemical and transport phenomena are modelled in a two-step procedure. This code, called STELE, was built by introducing a geochemical code, CHIMERE, into an existing transport code, METIS. At this stage, the code CHIMERE can take into account: any chemical reaction in aqueous phase (complexation, acid-base reaction, redox equilibrium), dissolution-precipitation of minerals and solid phases, dissolution-degassing of gas. The paper intends to describe the whole process leading to the coupling which can be forecasted over the next years between geochemical and transport models

  19. Novel Approaches for Mutual Coupling Reduction among Vertical and Planar Monopole Elements

    Science.gov (United States)

    Isaac, Ayman A.

    Modern wireless systems such as 4G LTE-A, RFID, Wi-Fi, WiMAX, and GPS utilize miniaturized antenna array elements to improve performance and reliability through diversity and increase throughput using spatial multiplexing schemes of MIMO systems. One original contribution in this thesis is to significantly reduce the complexity of traditional design approaches targeting mutual coupling reductions such as metamaterials, defected ground plane structures, soft electromagnetic surfaces using novel design alternatives. A decoupling network is proposed, which consists of a rectangular metallic ring along with two tuning strips printed on a dielectric substrate, surrounding a two-element monopole antenna array fed by a coplanar waveguide or microstrip structure. The array design offers a reduction in mutual coupling level by around 20 dB at 2.4 GHz as compared to the same array in which the two monopoles share the same ground plane but without the decoupling network. The array achieves a -10 dB S11 bandwidth of 0.63 GHz, (2.12 GHz - 2.75 GHz), a 0.24 GHz (2.33 GHz - 2.57 GHz) bandwidth in which S21 is less than -20 dB, respectively. A total realized gain of 1.6 to 1.69 dB in the frequency range over which S11 and S21 is less than -10 dB and -20 dB respectively. The boresight of the radiation patterns of two vertical monopole wire antennas operating at 2.4 GHz and separated by 8 mm are shown to be orthogonal and inclined by 45° with respect to the horizon while maintaining the shape of the isolated single antenna element. Hence, we denote this design as the descattered and decoupled orthogonal MIMO antenna array, which is reported for the first time in this dissertation, providing the ideal far-field radiation characteristics as theoretically deemed for handheld MIMO devices. Moreover, two new approaches for the reduction of mutual coupling between two rectangular planar monopole antennas printed on a dielectric substrate with a partial ground plane are presented in this

  20. A robust detector for rolling element bearing condition monitoring based on the modulation signal bispectrum and its performance evaluation against the Kurtogram

    Science.gov (United States)

    Tian, Xiange; Xi Gu, James; Rehab, Ibrahim; Abdalla, Gaballa M.; Gu, Fengshou; Ball, A. D.

    2018-02-01

    Envelope analysis is a widely used method for rolling element bearing fault detection. To obtain high detection accuracy, it is critical to determine an optimal frequency narrowband for the envelope demodulation. However, many of the schemes which are used for the narrowband selection, such as the Kurtogram, can produce poor detection results because they are sensitive to random noise and aperiodic impulses which normally occur in practical applications. To achieve the purposes of denoising and frequency band optimisation, this paper proposes a novel modulation signal bispectrum (MSB) based robust detector for bearing fault detection. Because of its inherent noise suppression capability, the MSB allows effective suppression of both stationary random noise and discrete aperiodic noise. The high magnitude features that result from the use of the MSB also enhance the modulation effects of a bearing fault and can be used to provide optimal frequency bands for fault detection. The Kurtogram is generally accepted as a powerful means of selecting the most appropriate frequency band for envelope analysis, and as such it has been used as the benchmark comparator for performance evaluation in this paper. Both simulated and experimental data analysis results show that the proposed method produces more accurate and robust detection results than Kurtogram based approaches for common bearing faults under a range of representative scenarios.

  1. On- and off-resonance radiation-atom-coupling matrix elements involving extended atomic wave functions

    Science.gov (United States)

    Komninos, Yannis; Mercouris, Theodoros; Nicolaides, Cleanthes A.

    2014-01-01

    In continuation of our earlier works, we present results concerning the computation of matrix elements of the multipolar Hamiltonian (MPH) between extended wave functions that are obtained numerically. The choice of the MPH is discussed in connection with the broader issue of the form of radiation-atom (or -molecule) interaction that is appropriate for the systematic solution of various problems of matter-radiation interaction. We derive analytic formulas, in terms of the sine-integral function and spherical Bessel functions of various orders, for the cumulative radial integrals that were obtained and calculated by Komninos, Mercouris, and Nicolaides [Phys. Rev. A 71, 023410 (2005), 10.1103/PhysRevA.71.023410]. This development allows the much faster and more accurate computation of such matrix elements, a fact that enhances the efficiency with which the time-dependent Schrödinger equation is solved nonperturbatively, in the framework of the state-specific expansion approach. The formulas are applicable to the general case where a pair of orbitals with angular parts |ℓ1,m1> and |ℓ2,m2> are coupled radiatively. As a test case, we calculate the matrix elements of the electric field and of the paramagnetic operators for on- and off-resonance transitions, between hydrogenic circular states of high angular momentum, whose quantum numbers are chosen so as to satisfy electric dipole and electric quadrupole selection rules. Because of the nature of their wave function (they are nodeless and the large centrifugal barrier keeps their overwhelming part at large distances from the nucleus), the validity of the electric dipole approximation in various applications where the off-resonance couplings must be considered becomes precarious. For example, for the transition from the circular state with n = 20 to that with n = 21, for which ≈400 a.u., the dipole approximation starts to fail already at XUV wavelengths (λ <125nm).

  2. Limitations of the electromagnetic isolation for multi-antenna systems on small terminals with capacitive coupling elements

    DEFF Research Database (Denmark)

    Pelosi, Mauro; Alrabadi, Osama; Franek, Ondrej

    2012-01-01

    Recently, there has been a growing interest for evaluating the performance potential of multiple antenna systems on small terminals. This work focuses on Capacitive Coupling Elements (CCEs), which are expected to perform differently with respect to self-resonating elements. Several CCEs...

  3. Influence of processing medium on frictional wear properties of ball bearing steel prepared by laser surface melting coupled with bionic principles

    International Nuclear Information System (INIS)

    Zhou Hong; Wang Chengtao; Guo Qingchun; Yu Jiaxiang; Wang Mingxing; Liao Xunlong; Zhao Yu; Ren Luquan

    2010-01-01

    Coupling with bionic principles, an attempt to improve the wear resistance of ball bearing steel (GCr15) with biomimetic units on the surface was made using a pulsed Nd: YAG laser. Air and water film was employed as processing medium, respectively. The microstructures of biomimeitc units were examined by scanning electron microscope and X-ray diffraction was used to describe the microstructure and identify the phases as functions of different mediums as well as water film with different thicknesses. The results indicated that the microstructure zones in the biomimetic specimens processed with water film were more refined and had better wear resistance increased by 55.8% in comparison with that processed in air; a significant improvement in microhardness was achieved by laser surface melting. The application of water film provided considerable microstructural changes and much more regular grain shape in biomimetic units, which played a key role in improving the wear resistance of ball bearing steel.

  4. Analysis of anisotropic crack problems using coupled meshless and fractal finite element method

    International Nuclear Information System (INIS)

    Rao, B N; Rajesh, K N

    2010-01-01

    This paper presents a coupling technique for integrating the element-free Galerkin method (EFGM) with fractal the finite element method (FFEM) for analyzing homogeneous, anisotropic, and two dimensional linear-elastic cracked structures subjected to mixed-mode (modes I and II) loading conditions. FFEM is adopted for discretization of domain close to the crack tip and EFGM is adopted in the rest of the domain. In the transition region interface elements are employed. The proposed method combines the best features of EFGM and FFEM, in the sense that no structured mesh or special enriched basis functions are necessary and no post-processing (employing any path independent integrals) is needed to determine fracture parameters such as stress intensity factors (SIFs) and T-stress. The numerical results based on all four orthotropic cases show that SIFs and T-stress obtained using the proposed method are in excellent agreement with the reference solutions for the structural and crack geometries considered in the present study.

  5. Inductively coupled plasma--atomic emission spectrometry: trace elements in oil matrices

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, Charlie Albert [Iowa State Univ., Ames, IA (United States)

    1977-12-01

    The simultaneous determination of up to 20 trace elements in various oil matrices by inductively coupled plasma-atomic emission spectrometry is reported. The oil matrices investigated were lubricating oils (for wear metals), fuel oil, centrifuged coal liquefaction product, crude soybean oil, and commercial edible oils. The samples were diluted with appropriate organic solvents and injected into the plasma as an aerosol generated by a pneumatic nebulization technique. Detection limits of the 28 elements studied ranged from 0.0006 to 9 μg/g with the majority falling in the 0.01 to 0.1 μg/g range. Analytical calibration curves were linear over at least two orders of magnitude and for some elements this linearity extended over 4.5 orders of magnitude. Relevant data on precision and accuracy are included. Because metals often occur as particles in lubricating oil and coal liquefaction products, the effect of particles on the analytical results was examined. Wear metal particles in used oil did not appear to affect the analytical results. However, incomplete recovery relative to organometallic reference solutions was obtained for iron particles with a nominal mean diameter of 3.0 μm suspended in oil. It was shown that the following factors contributed to incomplete recovery for the particles: settling of the suspended particles in the flask, a difference in nebulization efficiency between particle suspensions and organometallic solutions, and indications of incomplete vaporization of the larger particles in the plasma.

  6. Different Modelling Approaches to Coupling Wall and Floor Panels within a Dynamic Finite Element Model of a Lightweight Building

    DEFF Research Database (Denmark)

    Kiel, Nikolaj; Andersen, Lars Vabbersgaard; Niu, Bin

    2012-01-01

    . With the number of modules in the three axial directions defined, wall and floor panels are constructed, placed and coupled in the global model. The core of this modular finite element model consists of connecting the different panels to each other in a rational manner, where the accuracy is as high as possible......, with as many applications as possible, for the least possible computational cost. The coupling method of the structural panels in the above mentioned modular finite element model is in this paper discussed and evaluated. The coupling of the panels are performed using the commercial finite element program....... In this way a well-defined master geometry is present onto which all panels can be tied. But as the skeleton is an element itself, it will have a physical mass and a corresponding stiffness to be included in the linear system of equations. This means that the skeleton will influence the structure...

  7. On the Incorporation of Friction Into a Simultaneously Coupled Time Domain Model of a Rigid Rotor Supported by Air Foil Bearings

    DEFF Research Database (Denmark)

    von Osmanski, Alexander Sebastian; Larsen, Jon Steffen; Santos, Ilmar

    2017-01-01

    Despite decades of research, the dynamics of air foil bearings (AFBs) are not yet fully captured by any model,suggesting that the fundamental mechanisms of the AFB and their relative merits are not yet fully understood. The recent years have seen promising results from nonlinear time domain models......, allowing the dynamic pressure–compliance interaction and the unsteady terms of the compressible Reynolds equation to be considered. By including the simple elastic foundation model (SEFM) in a fully coupled simultaneous time integration, the dynamics of a rotor supported by industrial AFBs have previously...

  8. Application of Chan-Lam cross coupling for the synthesis of N-heterocyclic carbene precursors bearing strong electron donating or withdrawing groups

    Science.gov (United States)

    Huang, Liliang; He, Chengxiang; Sun, Zhihua

    2015-07-01

    Chan-Lam cross coupling allowed efficient synthesis of N,N’-disubstituted ortho-phenylene diamines bearing strong electron donating or withdrawing groups, such as nitro or methoxy groups, with moderate to high yields. These diamines can then be turned into N-heterocyclic carbene precursors after condensation with trimethyl orthoformate. The same strategy can also be utilized for the synthesis of N-monosubstituted aniline derivatives containing a functionalized ortho-aminomethyl group as intermediates for chiral 6-membered ring carbene precursors.

  9. Determination of rare earth elements by liquid chromatographic separation using inductively coupled plasma mass spectrometric detection

    International Nuclear Information System (INIS)

    Braverman, D.S.

    1992-01-01

    High-performance liquid chromatography (HPLC) is used to separate the rare earth elements (REEs) prior to detection by inductively coupled plasma mass spectrometry (ICP-MS). The use of HPLC-ICP-MS in series combines the separation power and speed of HPLC with the sensitivity, isotopic selectivity and speed of ICP-MS. The detection limits for the REEs are in the sub-ng ml -1 range and the response is linear over four orders of magnitude. A preliminary comparison of isotope dilution and external standard results for the determination of REEs in National Institute of Standards and Technology (NIST) Standard Reference Material (SRM 1633a) Fly Ash is presented. (author)

  10. Multielement determination of rare earth elements by liquid chromatography/inductively coupled plasma atomic emission spectrometry

    International Nuclear Information System (INIS)

    Sawatari, Hideyuki; Asano, Takaaki; Hu, Xincheng; Saizuka, Tomoo; Itoh, Akihide; Hirose, Akio; Haraguchi, Hiroki

    1995-01-01

    The rapid determination of rare earth elements (REEs) has been investigated by an on-line system of high performance liquid chromatography/multichannel inductively coupled plasma atomic emission spectrometry. In the present system, all REEs could be detected simultaneously in a single chromatographic measurement without spectral interferences. Utilizing a cation exchange column and 2-hydroxy-2-methylpropanoic acid aqueous solution as the mobile phase, the detection limits of 0.4-30 ng ml -1 for all REEs were obtained. The system was applied to the determination of REEs in geological standard rock samples and rare earth impurities in high purity rare earth oxides. The REEs in standard rocks could be determined by the present HPLC/ICP-AES system without pretreatment after acid digestion, although the detection limits were not sufficient for the analysis of rare earth oxides. (author)

  11. Computational Finite Element Software Assisted Development of a 3D Inductively Coupled Power Transfer System

    Directory of Open Access Journals (Sweden)

    P. Raval

    2014-02-01

    Full Text Available To date inductively coupled power transfer (ICPT systems have already found many practical applications including battery charging pads. In fact, current charging platforms tend to largely support only one- or two-dimensional planar movement in load. This paper proposes a new concept of extending the aspect ratios of the operating power transfer volume of ICPT systems to support arbitrary three dimensional load movements with respect to the primary coils. This is done by use of modern finite element method analysis software to propose the primary and secondary magnetic structures of such an ICPT system. Firstly, two primary magnetic structures are proposed based on contrasting modes of operation and different field directions. This includes a single-phase and multi-phase current model. Next, a secondary magnetic structure is customized to be compatible with both primary structures. The resulting system is shown to produce a 3D power transfer volume for battery cell charging applications.

  12. Ultrasonic wave propagation in viscoelastic cortical bone plate coupled with fluids: a spectral finite element study.

    Science.gov (United States)

    Nguyen, Vu-Hieu; Naili, Salah

    2013-01-01

    This work deals with the ultrasonic wave propagation in the cortical layer of long bones which is known as being a functionally graded anisotropic material coupled with fluids. The viscous effects are taken into account. The geometrical configuration mimics the one of axial transmission technique used for evaluating the bone quality. We present a numerical procedure adapted for this purpose which is based on the spectral finite element method (FEM). By using a combined Laplace-Fourier transform, the vibroacoustic problem may be transformed into the frequency-wavenumber domain in which, as radiation conditions may be exactly introduced in the infinite fluid halfspaces, only the heterogeneous solid layer needs to be analysed using FEM. Several numerical tests are presented showing very good performance of the proposed approach. We present some results to study the influence of the frequency on the first arriving signal velocity in (visco)elastic bone plate.

  13. Street-level classification of illicit heroin using inorganic elements coupled with pattern monitoring

    Directory of Open Access Journals (Sweden)

    Kar-Weng Chan

    2016-09-01

    Full Text Available A total of 96 illicit heroin samples seized in 2013–2014 were analyzed by inductively coupled plasma-mass spectrometry (ICP-MS to determine 16 inorganic elements at parts-per-billion (ppb level. Of eleven submissions, two or three samples with similar appearance were taken from the same seizure to form related samples. These samples were used to monitor the clustering outcome suggested by principal component analysis (PCA. They provided hints regarding the acceptance of within-seizure variability in-situ. The previously established data pretreatment method (N+4R did not function well with the present data probably due to the higher concentrations reported for the current samples. With the aid of the above-cited related samples for pattern monitoring, a better outcome was achieved when the pretreatment method was modified to employ solely standardization (S to optimize the necessary variability for sample classification.

  14. Thermo-mechanically coupled fracture analysis of shape memory alloys using the extended finite element method

    Science.gov (United States)

    Hatefi Ardakani, S.; Ahmadian, H.; Mohammadi, S.

    2015-04-01

    In this paper, the extended finite element method is used for fracture analysis of shape memory alloys for both cases of super elastic and shape memory effects. Heat generation during the forward and reverse phase transformations can lead to temperature variation in the material because of strong thermo-mechanical coupling, which significantly influences the SMA mechanical behavior. First, the stationary crack mode is studied and the effects of loading rate on material behavior in the crack tip are examined. Then, the crack propagation analysis is performed in the presence of an initial crack by adopting a weighted averaging criterion, where the direction of crack propagation is determined by weighted averaging of effective stresses at all the integration points in the vicinity of the crack tip. Finally, several numerical examples are analyzed and the obtained results are compared with the available reference results.

  15. A fully coupled finite element model for stress distribution in buried gas pipeline

    International Nuclear Information System (INIS)

    Yahya Sukirman; Zainal Zakaria; Woong Soon Yue

    2001-01-01

    The study of stress-strain relationship is very important in many designs of buried structures over the years. The behavior and mechanism between the interaction of soil and buried structures such as a natural pipeline will mostly contributes to the integrity of the pipeline. This paper presents a fully coupled finite element of consolidation analysis model to study the stress-strain distribution along a buried pipeline before it excess its maximum deformation limit. The behavior of the soil-pipeline system can be modelled by a non-linear elasto-plastic based on Mohr-Coulomb and critical state yield surfaces. The deformation and deflection of the pipeline due to drained and external loading condition will be considered here. Finally the stress-strain distribution of the buried pipeline will be utilised to obtain the maximum deformation limit and the deflection of the buried pipeline. (Author)

  16. A finite-element visualization of quantum reactive scattering. II. Nonadiabaticity on coupled potential energy surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Warehime, Mick [Chemical Physics Program, University of Maryland, College Park, Maryland 20742-2021 (United States); Kłos, Jacek; Alexander, Millard H., E-mail: mha@umd.edu [Department of Chemistry and Biochemistry and Institute of Physical Science and Technology, University of Maryland, College Park, Maryland 20742-2021 (United States)

    2015-01-21

    This is the second in a series of papers detailing a MATLAB based implementation of the finite element method applied to collinear triatomic reactions. Here, we extend our previous work to reactions on coupled potential energy surfaces. The divergence of the probability current density field associated with the two electronically adiabatic states allows us to visualize in a novel way where and how nonadiabaticity occurs. A two-dimensional investigation gives additional insight into nonadiabaticity beyond standard one-dimensional models. We study the F({sup 2}P) + HCl and F({sup 2}P) + H{sub 2} reactions as model applications. Our publicly available code (http://www2.chem.umd.edu/groups/alexander/FEM) is general and easy to use.

  17. Particle Swarm Optimization Algorithm Coupled with Finite Element Limit Equilibrium Method for Geotechnical Practices

    Directory of Open Access Journals (Sweden)

    Hongjun Li

    2012-01-01

    Full Text Available This paper proposes a modified particle swarm optimization algorithm coupled with the finite element limit equilibrium method (FELEM for the minimum factor of safety and the location of associated noncircular critical failure surfaces for various geotechnical practices. During the search process, the stress compatibility constraints coupled with the geometrical and kinematical compatibility constraints are firstly established based on the features of slope geometry and stress distribution to guarantee realistic slip surfaces from being unreasonable. Furthermore, in the FELEM, based on rigorous theoretical analyses and derivation, it is noted that the physical meaning of the factor of safety can be formulated on the basis of strength reserving theory rather than the overloading theory. Consequently, compared with the limit equilibrium method (LEM and the shear strength reduction method (SSRM through several numerical examples, the FELEM in conjunction with the improved search strategy is proved to be an effective and efficient approach to routine analysis and design in geotechnical practices with a high level of confidence.

  18. Optimization of on-line hydrogen stable isotope ratio measurements of halogen- and sulfur-bearing organic compounds using elemental analyzer–chromium/high-temperature conversion isotope ratio mass spectrometry (EA-Cr/HTC-IRMS)

    Science.gov (United States)

    Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B.; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A.; Schimmelmann, Arndt

    2017-01-01

    Rationale: Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H2) is responsible for non-quantitative H2 yields and possible hydrogen isotopic fractionation. Our previously introduced, new chromium-based EA-Cr/HTC-IRMS (Elemental Analyzer–Chromium/High-Temperature Conversion Isotope Ratio Mass Spectrometry) technique focused primarily on nitrogen-bearing compounds. Several technical and analytical issues concerning halogen- and sulfur-bearing samples, however, remained unresolved and required further refinement of the reactor systems.

  19. An efficient coupled polynomial interpolation scheme to eliminate material-locking in the Euler-Bernoulli piezoelectric beam finite element

    Directory of Open Access Journals (Sweden)

    Litesh N. Sulbhewar

    Full Text Available The convergence characteristic of the conventional two-noded Euler-Bernoulli piezoelectric beam finite element depends on the configuration of the beam cross-section. The element shows slower convergence for the asymmetric material distribution in the beam cross-section due to 'material-locking' caused by extension-bending coupling. Hence, the use of conventional Euler-Bernoulli beam finite element to analyze piezoelectric beams which are generally made of the host layer with asymmetrically surface bonded piezoelectric layers/patches, leads to increased computational effort to yield converged results. Here, an efficient coupled polynomial interpolation scheme is proposed to improve the convergence of the Euler-Bernoulli piezoelectric beam finite elements, by eliminating ill-effects of material-locking. The equilibrium equations, derived using a variational formulation, are used to establish relationships between field variables. These relations are used to find a coupled quadratic polynomial for axial displacement, having contributions from an assumed cubic polynomial for transverse displacement and assumed linear polynomials for layerwise electric potentials. A set of coupled shape functions derived using these polynomials efficiently handles extension-bending and electromechanical couplings at the field interpolation level itself in a variationally consistent manner, without increasing the number of nodal degrees of freedom. The comparison of results obtained from numerical simulation of test problems shows that the convergence characteristic of the proposed element is insensitive to the material configuration of the beam cross-section.

  20. A new program for calculating matrix elements of one-particle operators in jj-coupling

    International Nuclear Information System (INIS)

    Pyper, N.C.; Grant, I.P.; Beatham, N.

    1978-01-01

    The aim of this paper is to calculate the matrix elements of one-particle tensor operators occurring in atomic and nuclear theory between configuration state functions representing states containing any number of open shells in jj-coupling. The program calculates the angular part of these matrix elements. The program is essentially a new version of RDMEJJ, written by J.J. Chang. The aims of this version are to eliminate inconsistencies from RDMEJJ, to modify its input requirements for consistency with MCP75, and to modify its output so that it can be stored in a discfile for access by other compatible programs. The program assumes that the configurational states are built from a common orthonormal set of basis orbitals. The number of electrons in a shell having j>=9/2 is restricted to be not greater than 2 by the available CFP routines . The present version allows up to 40 orbitals and 50 configurational states with <=10 open shells; these numbers can be changed by recompiling with modified COMMON/DIMENSION statements. The user should ensure that the CPC library subprograms AAGD, ACRI incorporate all current updates and have been converted to use double precision floating point arithmetic. (Auth.)

  1. In situ 3D nanoprinting of free-form coupling elements for hybrid photonic integration

    Science.gov (United States)

    Dietrich, P.-I.; Blaicher, M.; Reuter, I.; Billah, M.; Hoose, T.; Hofmann, A.; Caer, C.; Dangel, R.; Offrein, B.; Troppenz, U.; Moehrle, M.; Freude, W.; Koos, C.

    2018-04-01

    Hybrid photonic integration combines complementary advantages of different material platforms, offering superior performance and flexibility compared with monolithic approaches. This applies in particular to multi-chip concepts, where components can be individually optimized and tested. The assembly of such systems, however, requires expensive high-precision alignment and adaptation of optical mode profiles. We show that these challenges can be overcome by in situ printing of facet-attached beam-shaping elements. Our approach allows precise adaptation of vastly dissimilar mode profiles and permits alignment tolerances compatible with cost-efficient passive assembly techniques. We demonstrate a selection of beam-shaping elements at chip and fibre facets, achieving coupling efficiencies of up to 88% between edge-emitting lasers and single-mode fibres. We also realize printed free-form mirrors that simultaneously adapt beam shape and propagation direction, and we explore multi-lens systems for beam expansion. The concept paves the way to automated assembly of photonic multi-chip systems with unprecedented performance and versatility.

  2. [Determination of Heavy Metal Elements in Diatomite Filter Aid by Inductively Coupled Plasma Mass Spectrometry].

    Science.gov (United States)

    Nie, Xi-du; Fu, Liang

    2015-11-01

    This study established a method for determining Be, Cr, Ni, As, Cd, Sb, Sn, Tl, Hg and Pb, total 10 heavy metals in diatomite filter aid. The diatomite filter aid was digested by using the mixture acid of HNO₃ + HF+ H₃PO₄ in microwave system, 10 heavy metals elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). The interferences of mass spectrometry caused by the high silicon substrate were optimized, first the equipment parameters and isotopes of test metals were selected to eliminate these interferences, the methane was selected as reactant gas, and the mass spectral interferences were eliminated by dynamic reaction cell (DRC). Li, Sc, Y, In and Bi were selected as the internal standard elements to correct the interferences caused by matrix and the drift of sensitivity. The results show that the detection limits for analyte is in the range of 3.29-15.68 ng · L⁻¹, relative standard deviations (RSD) is less than 4.62%, and the recovery is in the range of 90.71%-107.22%. The current method has some advantages such as, high sensitivity, accurate, and precision, which can be used in diatomite filter aid quality control and safety estimations.

  3. Sample diagnosis using indicator elements and non-analyte signals for inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Antler, Margaret; Ying Hai; Burns, David H.; Salin, Eric D.

    2003-01-01

    A sample diagnosis procedure that uses both non-analyte and analyte signals to estimate matrix effects in inductively coupled plasma-mass spectrometry is presented. Non-analyte signals are those of background species in the plasma (e.g. N + , ArO + ), and changes in these signals can indicate changes in plasma conditions. Matrix effects of Al, Ba, Cs, K and Na on 19 non-analyte signals and 15 element signals were monitored. Multiple linear regression was used to build the prediction models, using a genetic algorithm for objective feature selection. Non-analyte elemental signals and non-analyte signals were compared for diagnosing matrix effects, and both were found to be suitable for estimating matrix effects. Individual analyte matrix effect estimation was compared with the overall matrix effect prediction, and models used to diagnose overall matrix effects were more accurate than individual analyte models. In previous work [Spectrochim. Acta Part B 57 (2002) 277], we tested models for analytical decision making. The current models were tested in the same way, and were able to successfully diagnose matrix effects with at least an 80% success rate

  4. Rolling element bearing fault diagnosis based on Over-Complete rational dilation wavelet transform and auto-correlation of analytic energy operator

    Science.gov (United States)

    Singh, Jaskaran; Darpe, A. K.; Singh, S. P.

    2018-02-01

    Local damage in rolling element bearings usually generates periodic impulses in vibration signals. The severity, repetition frequency and the fault excited resonance zone by these impulses are the key indicators for diagnosing bearing faults. In this paper, a methodology based on over complete rational dilation wavelet transform (ORDWT) is proposed, as it enjoys a good shift invariance. ORDWT offers flexibility in partitioning the frequency spectrum to generate a number of subbands (filters) with diverse bandwidths. The selection of the optimal filter that perfectly overlaps with the bearing fault excited resonance zone is based on the maximization of a proposed impulse detection measure "Temporal energy operated auto correlated kurtosis". The proposed indicator is robust and consistent in evaluating the impulsiveness of fault signals in presence of interfering vibration such as heavy background noise or sporadic shocks unrelated to the fault or normal operation. The structure of the proposed indicator enables it to be sensitive to fault severity. For enhanced fault classification, an autocorrelation of the energy time series of the signal filtered through the optimal subband is proposed. The application of the proposed methodology is validated on simulated and experimental data. The study shows that the performance of the proposed technique is more robust and consistent in comparison to the original fast kurtogram and wavelet kurtogram.

  5. Rotor dynamic behaviour of a high-speed oil-free motor compressor with a rigid coupling supported on four radial magnetic bearings

    Science.gov (United States)

    Schmied, J.; Pradetto, J. C.

    1994-01-01

    The combination of a high-speed motor, dry gas seals, and magnetic bearings realized in this unit facilitates the elimination of oil. The motor is coupled with a quill shaft to the compressor. This yields higher natural frequencies of the rotor than with the use of a diaphragm coupling and helps to maintain a sufficient margin of the maximum speed to the frequency of the second compressor bending mode. However, the controller of each bearing then has to take the combined modes of both machines into account. The requirements for the controller to ensure stability and sufficient damping of all critical speeds are designed and compared with the implemented controller. The calculated closed loop behavior was confirmed experimentally, except the stability of some higher modes due to slight frequency deviations of the rotor model to the actual rotor. The influence of a mechanical damper as a device to provide additional damping to high models is demonstrated theoretically. After all, it was not necessary to install the damper, since all modes cold be stabilized by the controller.

  6. A finite-element simulation of galvanic coupling intra-body communication based on the whole human body.

    Science.gov (United States)

    Song, Yong; Zhang, Kai; Hao, Qun; Hu, Lanxin; Wang, Jingwen; Shang, Fuzhou

    2012-10-09

    Simulation based on the finite-element (FE) method plays an important role in the investigation of intra-body communication (IBC). In this paper, a finite-element model of the whole body model used for the IBC simulation is proposed and verified, while the FE simulation of the galvanic coupling IBC with different signal transmission paths has been achieved. Firstly, a novel finite-element method for modeling the whole human body is proposed, and a FE model of the whole human body used for IBC simulation was developed. Secondly, the simulations of the galvanic coupling IBC with the different signal transmission paths were implemented. Finally, the feasibility of the proposed method was verified by using in vivo measurements within the frequency range of 10 kHz-5 MHz, whereby some important conclusions were deduced. Our results indicate that the proposed method will offer significant advantages in the investigation of the galvanic coupling intra-body communication.

  7. System-Level Coupled Modeling of Piezoelectric Vibration Energy Harvesting Systems by Joint Finite Element and Circuit Analysis

    Directory of Open Access Journals (Sweden)

    Congcong Cheng

    2016-01-01

    Full Text Available A practical piezoelectric vibration energy harvesting (PVEH system is usually composed of two coupled parts: a harvesting structure and an interface circuit. Thus, it is much necessary to build system-level coupled models for analyzing PVEH systems, so that the whole PVEH system can be optimized to obtain a high overall efficiency. In this paper, two classes of coupled models are proposed by joint finite element and circuit analysis. The first one is to integrate the equivalent circuit model of the harvesting structure with the interface circuit and the second one is to integrate the equivalent electrical impedance of the interface circuit into the finite element model of the harvesting structure. Then equivalent circuit model parameters of the harvesting structure are estimated by finite element analysis and the equivalent electrical impedance of the interface circuit is derived by circuit analysis. In the end, simulations are done to validate and compare the proposed two classes of system-level coupled models. The results demonstrate that harvested powers from the two classes of coupled models approximate to theoretic values. Thus, the proposed coupled models can be used for system-level optimizations in engineering applications.

  8. Determination of trace and ultra-trace elements in Dergaon meteorite by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Balaram, V.; Gnaneswara Rao, T.; Anjaiah, K.V.; Phukon, N.; Majumdar, A.C.

    2003-01-01

    In this paper, a detailed methodology for high precision measurement of several trace and ultra-trace elements including REE and PGE have been presented using effective sample preparation techniques and inductively coupled plasma mass spectrometry. Discussion is focussed on aspects, such as total dissolution and recovery of all elements, minimization of oxide and doubly-charged and other polyatomic ion interferences, calibration by matrix matching standards, accuracy and precision

  9. Development of a diffuse element matrix in 'planar' technology. A particular application: logical gate with coupled emitter

    International Nuclear Information System (INIS)

    Rousseau, P.

    1968-01-01

    In a first part, after a brief recall concerning 'planar' technology we discuss the various parasitic elements associated with integrated circuits components. Mathematical formulae of these elements are derived. In a second part, we present a matrix of 22 transistors and 12 resistors which has been realized. This matrix enables the integration of the major part of nuclear circuits. Some of the obtained circuits are shown, particularly an emitter coupled logic gate which presents good electrical behaviour. (author) [fr

  10. Implementation of fully coupled heat and mass transport model to determine the behaviour of timber elements in fire

    DEFF Research Database (Denmark)

    Pečenko, Robert; Huč, Sabina; Turk, Goran

    2014-01-01

    In this paper we present results of numerical analysis of timber beam exposed to fire. The numerical procedure is divided into two physically separated but closely related phases. In the first phase coupled problem of moisture and heat transfer over the timber beam is numerically solved using...... the enhanced finite element method. The results of the first computational stage were used as the input data for the numerical analysis of mechanical response of timber element....

  11. A discontinuous finite element approach to cracking in coupled poro-elastic fluid flow models

    Science.gov (United States)

    Wilson, C. R.; Spiegelman, M. W.; Evans, O.; Ulven, O. I.; Sun, W.

    2016-12-01

    Reaction-driven cracking is a coupled process whereby fluid-induced reactions drive large volume changes in the host rock which produce stresses leading to crack propagation and failure. This in turn generates new surface area and fluid-flow pathways for subsequent reaction in a potentially self-sustaining system. This mechanism has has been proposed for the pervasive serpentinization and carbonation of peridotite, as well as applications to mineral carbon sequestration and hydrocarbon extraction. The key computational issue in this problem is implementing algorithms that adequately model the formation of discrete fractures. Here we present models using a discontinuous finite element method for modeling fracture formation (Radovitsky et al., 2011). Cracks are introduced along facets of the mesh by the relaxation of penalty parameters once a failure criterion is met. It is fully described in the weak form of the equations, requiring no modification of the underlying mesh structure and allowing fluid properties to be easily adjusted along cracked facets. To develop and test the method, we start by implementing the algorithm for the simplified Biot equations for poro-elasticity using the finite element model assembler TerraFERMA. We consider hydro-fracking around a borehole (Grassl et al., 2015), where elevated fluid pressure in the poro-elastic solid causes it to fail radially in tension. We investigate the effects of varying the Biot coefficient and adjusting the fluid transport properties in the vicinity of the crack and compare our results to related dual-graph models (Ulven & Sun, submitted). We discuss issues arising from this method, including the formation of null spaces and appropriate preconditioning and solution strategies. Initial results suggest that this method provides a promising way to incorporate cracking into our reactive fluid flow models and future work aims to integrate the mechanical and chemical aspects of this process.

  12. Laser ablation inductively coupled plasma mass spectrometry for the determination of trace elements in soil

    International Nuclear Information System (INIS)

    Lee Yiling; Chang Chaochiang; Jiang Shiuhjen

    2003-01-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been applied to the determination of Cr, Cu, Zn, Cd and Pb in soil samples. The dried soil powder was pressed into a pellet for LA-ICP-MS analysis. Triton X-100 was added to work as the modifier to enhance the ion signals. The influences of instrument operating conditions (LA and ICP-MS) and pellet preparation on the ion signals were reported. For Cr determination, the ICP-MS was operated under the dynamic reaction cell mode which alleviated the mass overlap interference. Standard addition method and isotope dilution method were used for the quantitation work. The powder sample was spiked with suitable amounts of element standards and/or enriched isotopes, well-mixed, dried and then pressed into a pellet for LA-ICP-MS analysis. This method has been applied to determine Cr, Cu, Zn, Cd and Pb in NIST SRM 2711 Montana soil and NIST SRM 2709 San Joaquin soil reference materials. The analysis results were in agreement with the certified values. The precision between sample replicates was better than 5% with LA-ICP-MS method. Detection limits estimated from standard addition curves were approximately 0.9, 2, 9, 0.7 and 0.3 ng g -1 for Cr, Cu, Zn, Cd and Pb, respectively

  13. Fundamental and methodological investigations for the improvement of elemental analysis by inductively coupled plasma mass soectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, Christopher Hysjulien [Ames Lab., Ames, IA (United States)

    2012-01-01

    This dissertation describes a variety of studies meant to improve the analytical performance of inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation (LA) ICP-MS. The emission behavior of individual droplets and LA generated particles in an ICP is studied using a high-speed, high frame rate digital camera. Phenomena are observed during the ablation of silicate glass that would cause elemental fractionation during analysis by ICP-MS. Preliminary work for ICP torch developments specifically tailored for the improvement of LA sample introduction are presented. An abnormal scarcity of metal-argon polyatomic ions (MAr{sup +}) is observed during ICP-MS analysis. Evidence shows that MAr{sup +} ions are dissociated by collisions with background gas in a shockwave near the tip of the skimmer cone. Method development towards the improvement of LA-ICP-MS for environmental monitoring is described. A method is developed to trap small particles in a collodion matrix and analyze each particle individually by LA-ICP-MS.

  14. Mechanical behavior and coupling between mechanical and oxidation in alloy 718: effect of solide solution elements

    International Nuclear Information System (INIS)

    Max, Bertrand

    2014-01-01

    Alloy 718 is the superalloy the most widely used in industry due to its excellent mechanical properties, as well as oxidation and corrosion resistance in wide range of temperatures and solicitation modes. Nevertheless, it is a well-known fact that this alloy is sensitive to stress corrosion cracking and oxidation assisted cracking under loading in the range of temperatures met in service. Mechanisms explaining this phenomenon are not well understood: nevertheless, it is well established that a relation exists between a change in fracture mode and the apparition of plastic instabilities phenomenon. During this study, the instability phenomenon, Portevin-Le Chatelier effect, in alloy 718 was studied by tensile tests in wide ranges of temperatures and strain rates. Different domains of plastic instabilities have been evidenced. Their characteristics suggest the existence of interactions between dislocations and different types of solute elements: interstitials for lower temperatures and substitutionals for higher testing temperatures. Mechanical spectroscopy tests have been performed on alloy 718 and various alloys which composition is comparable to that of alloy 718. These tests prove the mobility of molybdenum atoms in the alloy in the studied temperature range. Specific tests have been performed to study interaction phenomenon between plasticity and oxidation. These results highlight the strong effect of plastic strain rate on both mechanical behavior and intergranular cracking in alloy 718. The subsequent discussion leads to propose hypothesis on coupling effects between deformation mechanisms and oxidation assisted embrittlement in the observed cracking processes. (author)

  15. PIXE micro-mapping of minor elements in Hypatia, a diamond bearing carbonaceous stone from the Libyan Desert Glass area, Egypt: Inheritance from a cold molecular cloud?

    Energy Technology Data Exchange (ETDEWEB)

    Andreoli, M.A.G., E-mail: marco.andreoli@wits.ac.za [School of Geosciences, University of the Witwatersrand, P.O. Box 3, Wits 2050 (South Africa); Przybylowicz, W.J. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); AGH University of Science and Technology, Faculty of Physics & Applied Computer Science, al. A. Mickiewicza 30, 30-059 Kraków (Poland); Kramers, J.; Belyanin, G. [Department of Geology, University of Johannesburg, Auckland Park 2006 (South Africa); Westraadt, J. [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Bamford, M. [Evolutionary Studies Institute, University of the Witwatersrand, P.O. Box 3, Wits 2050 (South Africa); Mesjasz-Przybylowicz, J. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West 7129 (South Africa); Venter, A. [South African Nuclear Energy Corporation, P.O. Box 582, Pretoria 0001 (South Africa)

    2015-11-15

    Matter originating from space, particularly if it represents rare meteorite samples, is ideally suited to be studied by Particle Induced X-ray Emission (PIXE) as this analytical technique covers a broad range of trace elements and is per se non-destructive. We describe and interpret a set of micro-PIXE elemental maps obtained on two minute (weighing about 25 and 150 mg), highly polished fragments taken from Hypatia, a controversial, diamond-bearing carbonaceous pebble from the SW Egyptian desert. PIXE data show that Hypatia is chemically heterogeneous, with significant amounts of primordial S, Cl, P and at least 10 elements with Z > 21 (Ti, V, Cr, Mn, Fe, Ni, Os, Ir) locally attaining concentrations above 500 ppm. Si, Al, Ca, K, O also occur, but are predominantly confined to cracks and likely represent contamination from the desert environment. Unusual in the stone is poor correlation between elements within the chalcophile (S vs. Cu, Zn) and siderophile (i.e.: Fe vs. Ni, Ir, Os) groups, whereas other siderophiles (Mn, Mo and the Platinum group elements (PGEs)) mimic the distribution of lithophile elements such as Cr and V. Worthy of mention is also the presence of a globular domain (Ø ∼ 120 μm) that is C and metals-depleted, yet Cl (P)-enriched (>3 wt.% and 0.15 wt.% respectively). While the host of the Cl remains undetermined, this chemical unit is enclosed within a broader domain that is similarly C-poor, yet Cr–Ir rich (up to 1.2 and 0.3 wt.% respectively). Our data suggest that the pebble consists of shock-compacted, primitive carbonaceous material enriched in cold, pre-solar dust.

  16. PIXE micro-mapping of minor elements in Hypatia, a diamond bearing carbonaceous stone from the Libyan Desert Glass area, Egypt: Inheritance from a cold molecular cloud?

    International Nuclear Information System (INIS)

    Andreoli, M.A.G.; Przybylowicz, W.J.; Kramers, J.; Belyanin, G.; Westraadt, J.; Bamford, M.; Mesjasz-Przybylowicz, J.; Venter, A.

    2015-01-01

    Matter originating from space, particularly if it represents rare meteorite samples, is ideally suited to be studied by Particle Induced X-ray Emission (PIXE) as this analytical technique covers a broad range of trace elements and is per se non-destructive. We describe and interpret a set of micro-PIXE elemental maps obtained on two minute (weighing about 25 and 150 mg), highly polished fragments taken from Hypatia, a controversial, diamond-bearing carbonaceous pebble from the SW Egyptian desert. PIXE data show that Hypatia is chemically heterogeneous, with significant amounts of primordial S, Cl, P and at least 10 elements with Z > 21 (Ti, V, Cr, Mn, Fe, Ni, Os, Ir) locally attaining concentrations above 500 ppm. Si, Al, Ca, K, O also occur, but are predominantly confined to cracks and likely represent contamination from the desert environment. Unusual in the stone is poor correlation between elements within the chalcophile (S vs. Cu, Zn) and siderophile (i.e.: Fe vs. Ni, Ir, Os) groups, whereas other siderophiles (Mn, Mo and the Platinum group elements (PGEs)) mimic the distribution of lithophile elements such as Cr and V. Worthy of mention is also the presence of a globular domain (Ø ∼ 120 μm) that is C and metals-depleted, yet Cl (P)-enriched (>3 wt.% and 0.15 wt.% respectively). While the host of the Cl remains undetermined, this chemical unit is enclosed within a broader domain that is similarly C-poor, yet Cr–Ir rich (up to 1.2 and 0.3 wt.% respectively). Our data suggest that the pebble consists of shock-compacted, primitive carbonaceous material enriched in cold, pre-solar dust.

  17. The determination of low level trace elements in coals by laser ablation-inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Booth, C.A.; Spears, D.A.; Krause, P.; Cox, A.G. [University of Sheffield, Sheffield (United Kingdom). Dept. of Earth Sciences

    1999-11-01

    The rapid determination of elements present in low level concentrations in bituminous coals is possible using laser abalation-inductively coupled plasma-mass spectrometry (l.a.-i.c.p.-m.s.). A wide range of trace elements can routinely be determined using this technique but it is for environmentally sensitive elements, such as As, Cd, Mo, Sb, Se and Hg, that it is of most use due to the low levels of detection. Calibration of the i.c.p.-m.s. was achieved using a series of uncertified coals and the method evaluated using the South African certified coals, Sarm 18, 19 and 20. A critical evaluation of the data obtained shows that for many of the elements studied the results obtained are both accurate and precise, even at very low concentrations, with the limits of detection for all of the elements being in the {mu}g/kg (parts per billion) range. 6 refs., 3 figs., 9 tabs.

  18. Comparison of composite rotor blade models: A coupled-beam analysis and an MSC/NASTRAN finite-element model

    Science.gov (United States)

    Hodges, Robert V.; Nixon, Mark W.; Rehfield, Lawrence W.

    1987-01-01

    A methodology was developed for the structural analysis of composite rotor blades. This coupled-beam analysis is relatively simple to use compared with alternative analysis techniques. The beam analysis was developed for thin-wall single-cell rotor structures and includes the effects of elastic coupling. This paper demonstrates the effectiveness of the new composite-beam analysis method through comparison of its results with those of an established baseline analysis technique. The baseline analysis is an MSC/NASTRAN finite-element model built up from anisotropic shell elements. Deformations are compared for three linear static load cases of centrifugal force at design rotor speed, applied torque, and lift for an ideal rotor in hover. A D-spar designed to twist under axial loading is the subject of the analysis. Results indicate the coupled-beam analysis is well within engineering accuracy.

  19. A novel efficient coupled polynomial field interpolation scheme for higher order piezoelectric extension mode beam finite elements

    International Nuclear Information System (INIS)

    Sulbhewar, Litesh N; Raveendranath, P

    2014-01-01

    An efficient piezoelectric smart beam finite element based on Reddy’s third-order displacement field and layerwise linear potential is presented here. The present formulation is based on the coupled polynomial field interpolation of variables, unlike conventional piezoelectric beam formulations that use independent polynomials. Governing equations derived using a variational formulation are used to establish the relationship between field variables. The resulting expressions are used to formulate coupled shape functions. Starting with an assumed cubic polynomial for transverse displacement (w) and a linear polynomial for electric potential (φ), coupled polynomials for axial displacement (u) and section rotation (θ) are found. This leads to a coupled quadratic polynomial representation for axial displacement (u) and section rotation (θ). The formulation allows accommodation of extension–bending, shear–bending and electromechanical couplings at the interpolation level itself, in a variationally consistent manner. The proposed interpolation scheme is shown to eliminate the locking effects exhibited by conventional independent polynomial field interpolations and improve the convergence characteristics of HSDT based piezoelectric beam elements. Also, the present coupled formulation uses only three mechanical degrees of freedom per node, one less than the conventional formulations. Results from numerical test problems prove the accuracy and efficiency of the present formulation. (paper)

  20. Schemes for applying active lubrication to main engine bearings

    DEFF Research Database (Denmark)

    Estupinan, Edgar Alberto; Santos, Ilmar

    2009-01-01

    -difference method. The computed bearing fluid film forces are coupled to the set of nonlinear equations that describes the dynamics of the reciprocating engine, obtained with the help of multibody dynamics (rigid components) and finite elements method (flexible components). The main equations that govern...

  1. A Parameter Study of Coupling Properties in Finite Element Models of Single-Stud Double-Plate Panels

    DEFF Research Database (Denmark)

    Dickow, Kristoffer Ahrens; Domadiya, Parthkumar Gandalal; Andersen, Lars Vabbersgaard

    2011-01-01

    Lightweight building techniques are currently progressing fast and using such structures for multi-storey multi-family dwellings is becoming part of the industry standard. Partitions in lightweight buildings are often constructed as plates on frame structures made of either wood or steel. In any...... case the low frequency sound transmission is often an issue that needs attention. The present paper utilizes a finite element model of a single-stud double-plate panel structure to investigate how different couplings between the plates and the frame structure affect the direct sound transmission. Four...... different coupling configurations are considered: 1) All structural contact points are completely tied; 2) only nodes on the centre lines of the structure are tied; 3) a narrow strip of tied elements connect the frame to the plates; 4) evenly spaced discrete elements are tied. In all cases the interaction...

  2. Geochemical study for primary dispersion of trace elements in uranium bearing black slates of the Ogcheon Group, Korea

    International Nuclear Information System (INIS)

    Kim, O.B.

    1980-01-01

    Total 145 boring core samples of Deogpyongri, Geosan and Mogsori, Geumsan in Ogcheon Group have been collected and analyzed for uranium and trace elements such as lead, zinc, copper, chromium, cadmium, vanadium and mloybdenium. All the data of the elments analyzed have been processed statistically by computer in order to estimate the correlation co-efficient between elements. The vertical distribution pattern of trace elements has been discussed. The results obtained are summarized as follows: Uranium has high correlation co-efficients with vanadium and molybdenium. And the last two can be used as indicator elements for the geochemical prospecting of uranium. The occurrence of uranium is closely related with the carbonaceous material in boring core of Ogcheon Group. Considering the vertical distribution pattern of uranium, it can't be said that the epigenetic uranium absorption to the carbonaceous material is in progress. The uranium minerals in the carbonanceous material must be correctly defined to resolve the genetic problems of uranium deposit in Ogcheon Group. (Author)

  3. Maxwell's equations in axisymmetrical geometry: coupling H(curl) finite element in volume and H(div) finite element in surface. The numerical code FuMel

    International Nuclear Information System (INIS)

    Cambon, S.; Lacoste, P.

    2011-01-01

    We propose a finite element method to solve the axisymmetric scattering problem posed on a regular bounded domain. Here we shall show how to reduce the initial 3D problem into a truncated sum of 2D independent problems posed into a meridian plane of the object. Each of these problem results in the coupling of a partial differential equation into the interior domain and an integral equation on the surface simulating the free space. Then variational volume and boundary integral formulations of Maxwell's equation on regular surfaces are derived. We introduce some general finite element adapted to cylindrical coordinates and constructed from nodal and mixed finite element both for the interior (volume) and for the integral equation (surface). (authors)

  4. Elements of a compatible optimization theory for coupled systems; Elements d'une theorie de l'optimisation compatible de systemes couples

    Energy Technology Data Exchange (ETDEWEB)

    Bonnemay, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    The first theory deals with the compatible optimization in coupled systems. A game theory for two players and with a non-zero sum is first developed. The conclusions are then extended to the case of a game with any finite number of players. After this essentially static study, the dynamic aspect of the problem is applied to the case of games which evolve. By applying PONTRYAGIN maximum principle it is possible to derive a compatible optimisation theorem which constitutes a necessary condition. (author) [French] La premiere these traite de l'optimalisation compatible des systemes couples. Une theorie du jeu a deux joueurs et a somme non nulle est d'abord developpee. Ses conclusions sont etendues ensuite au jeu a un nombre fini quelconque de joueurs. Apres cette etude essentiellement statique, l'aspect dynamique du probleme est introduit dans les jeux evolutifs. L'application du principe du maximum de PONTRYAGIN permet d'enoncer un theoreme d'optimalite compatible qui constitue une condition necessaire. (auteur)

  5. Elements of a compatible optimization theory for coupled systems; Elements d'une theorie de l'optimisation compatible de systemes couples

    Energy Technology Data Exchange (ETDEWEB)

    Bonnemay, A. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1969-07-01

    The first theory deals with the compatible optimization in coupled systems. A game theory for two players and with a non-zero sum is first developed. The conclusions are then extended to the case of a game with any finite number of players. After this essentially static study, the dynamic aspect of the problem is applied to the case of games which evolve. By applying PONTRYAGIN maximum principle it is possible to derive a compatible optimisation theorem which constitutes a necessary condition. (author) [French] La premiere these traite de l'optimalisation compatible des systemes couples. Une theorie du jeu a deux joueurs et a somme non nulle est d'abord developpee. Ses conclusions sont etendues ensuite au jeu a un nombre fini quelconque de joueurs. Apres cette etude essentiellement statique, l'aspect dynamique du probleme est introduit dans les jeux evolutifs. L'application du principe du maximum de PONTRYAGIN permet d'enoncer un theoreme d'optimalite compatible qui constitue une condition necessaire. (auteur)

  6. Hydro-mechanical coupled simulation of hydraulic fracturing using the eXtended Finite Element Method (XFEM)

    Science.gov (United States)

    Youn, Dong Joon

    This thesis presents the development and validation of an advanced hydro-mechanical coupled finite element program analyzing hydraulic fracture propagation within unconventional hydrocarbon formations under various conditions. The realistic modeling of hydraulic fracturing is necessarily required to improve the understanding and efficiency of the stimulation technique. Such modeling remains highly challenging, however, due to factors including the complexity of fracture propagation mechanisms, the coupled behavior of fracture displacement and fluid pressure, the interactions between pre-existing natural and initiated hydraulic fractures and the formation heterogeneity of the target reservoir. In this research, an eXtended Finite Element Method (XFEM) scheme is developed allowing for representation of single or multiple fracture propagations without any need for re-meshing. Also, the coupled flows through the fracture are considered in the program to account for their influence on stresses and deformations along the hydraulic fracture. In this research, a sequential coupling scheme is applied to estimate fracture aperture and fluid pressure with the XFEM. Later, the coupled XFEM program is used to estimate wellbore bottomhole pressure during fracture propagation, and the pressure variations are analyzed to determine the geometry and performance of the hydraulic fracturing as pressure leak-off test. Finally, material heterogeneity is included into the XFEM program to check the effect of random formation property distributions to the hydraulic fracture geometry. Random field theory is used to create the random realization of the material heterogeneity with the consideration of mean, standard deviation, and property correlation length. These analyses lead to probabilistic information on the response of unconventional reservoirs and offer a more scientific approach regarding risk management for the unconventional reservoir stimulation. The new stochastic approach

  7. Bearing restoration by grinding

    Science.gov (United States)

    Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

    1976-01-01

    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

  8. Partitioning and Leaching Behavior of Actinides and Rare Earth Elements in a Zirconolite- Bearing Hydrothermal Vein System

    International Nuclear Information System (INIS)

    Payne, Timothy E.; Hart, Kaye P.; Lumpkin, Gregory R.; McGlinn, Peter J.; Giere, Reto

    2007-01-01

    Chemical extraction techniques and scanning electron microscopy were used to study the distribution and behavior of actinides and rare earth elements (REE) in hydrothermal veins at Adamello (Italy). The six samples discussed in this paper were from the phlogopite zone, which is one of the major vein zones. The samples were similar in their bulk chemical composition, mineralogy, and leaching behavior of major elements (determined by extraction with 9 M HCl). However, there were major differences in the extractability of REE and actinides. The most significant influence on the leaching characteristics appears to be the amounts of U, Th and REE incorporated in resistant host phases (zirconolite and titanite) rather than readily leached phases (such as apatite). Uranium and Th are very highly enriched in zirconolite grains. Actinides were more readily leached from samples with a higher content of U and Th, relative to the amount of zirconium. The results show that REE and actinides present in chemically resistant host minerals can be retained under aggressive leaching conditions. (authors)

  9. Elemental labelling combined with liquid chromatography inductively coupled plasma mass spectrometry for quantification of biomolecules: A review

    International Nuclear Information System (INIS)

    Kretschy, Daniela; Koellensperger, Gunda; Hann, Stephan

    2012-01-01

    Highlights: ► Survey of bio-analytical approaches utilizing biomolecule labelling. ► Detailed discussion of methodology and chemistry of elemental labelling. ► Biomedical and bio-analytical applications of elemental labelling. ► FI-ICP-MS and LC–ICP-MS for quantification of elemental labelled biomolecules. ► Review of selected applications. - Abstract: This article reviews novel quantification concepts where elemental labelling is combined with flow injection inductively coupled plasma mass spectrometry (FI-ICP-MS) or liquid chromatography inductively coupled plasma mass spectrometry (LC–ICP-MS), and employed for quantification of biomolecules such as proteins, peptides and related molecules in challenging sample matrices. In the first sections an overview on general aspects of biomolecule quantification, as well as of labelling will be presented emphasizing the potential, which lies in such methodological approaches. In this context, ICP-MS as detector provides high sensitivity, selectivity and robustness in biological samples and offers the capability for multiplexing and isotope dilution mass spectrometry (IDMS). Fundamental methodology of elemental labelling will be highlighted and analytical, as well as biomedical applications will be presented. A special focus will lie on established applications underlining benefits and bottlenecks of such approaches for the implementation in real life analysis. Key research made in this field will be summarized and a perspective for future developments including sophisticated and innovative applications will given.

  10. 1ST-ORDER NONADIABATIC COUPLING MATRIX-ELEMENTS FROM MULTICONFIGURATIONAL SELF-CONSISTENT-FIELD RESPONSE THEORY

    DEFF Research Database (Denmark)

    Bak, Keld L.; Jørgensen, Poul; Jensen, H.J.A.

    1992-01-01

    A new scheme for obtaining first-order nonadiabatic coupling matrix elements (FO-NACME) for multiconfigurational self-consistent-field (MCSCF) wave functions is presented. The FO-NACME are evaluated from residues of linear response functions. The residues involve the geometrical response of a ref......A new scheme for obtaining first-order nonadiabatic coupling matrix elements (FO-NACME) for multiconfigurational self-consistent-field (MCSCF) wave functions is presented. The FO-NACME are evaluated from residues of linear response functions. The residues involve the geometrical response...... to the full configuration interaction limit. Comparisons are made with state-averaged MCSCF results for MgH2 and finite-difference configuration interaction by perturbation with multiconfigurational zeroth-order wave function reflected by interactive process (CIPSI) results for BH....

  11. Development of a diffuse element matrix in 'planar' technology. A particular application: logical gate with coupled emitter; Etude et realisation d'une matrice d'elements diffuses selon la technologie 'planar'. Application particuliere: porte logique a emetteurs couples

    Energy Technology Data Exchange (ETDEWEB)

    Rousseau, P [Commissariat a l' Energie Atomique, 38 - Grenoble (France). Centre d' Etudes Nucleaires

    1967-06-01

    In a first part, after a brief recall concerning 'planar' technology we discuss the various parasitic elements associated with integrated circuits components. Mathematical formulae of these elements are derived. In a second part, we present a matrix of 22 transistors and 12 resistors which has been realized. This matrix enables the integration of the major part of nuclear circuits. Some of the obtained circuits are shown, particularly an emitter coupled logic gate which presents good electrical behaviour. (author) [French] Dans uns premiere partie, apres un bref rappel de la technologie 'planar' nous etudions les divers elements parasites associes a tout composant d'un circuit integre. Un developpement sommaire des expressions mathematiques de ces elements est propose. Dans une seconde partie nous presentons la matrice de 22 transistors et 12 resistances que nous avons realisee. Cette matrice repond aux principaux besoins de l'electronique nucleaire. Nous proposons ensuite quelques exemples de circuits realises a partir de cette matrice dont notamment une porte logique a emetteurs couples de performances tres interessantes. (auteur)

  12. From Hybrid to Actively-Controlled Gas Lubricated Bearings – Theory and Experiment

    DEFF Research Database (Denmark)

    Morosi, Stefano

    bearings, tilting pad and flexure pivot gas bearings. These solutions proved to be effective in improving static and dynamic properties of the bearings, however issues related to the manufacturing and accuracy of predictions has so far limited their applications. Another drawback is that passive bearings......-rig are backed by a comprehensive mathematical model that couples a finite element model of a flexible rotor, a thermohydrodynamic model based on a modified form of the Reynold’s equation for hybrid aerostatic-aerodynamic lubrication of compressible fluid, a piezoelectric injection system and a proportional...

  13. Qualitative analysis of the rare earth element by simulation of inductively coupled plasma emission spectra

    International Nuclear Information System (INIS)

    Hashimoto, M.S.; Tobishima, Taeko; Kamitake, Seigo; Yasuda, Kazuo.

    1985-01-01

    The emission lines for qualitative analysis of rare earth elements by a simulation technique of ICP spectra were proposed. The spectra were simulated by employing a Gaussian (or a Lorentzian at high concentrations) profile. The simulated spectra corresponded quite well with the observed ones. The emission lines were selected so that the interference was as small as possible. The present qualitative analysis is based on a pattern recognition method where observed intensity ratios of the emission lines in each element are compared with those of a single analyte element. The qualitative analysis was performed for twelve standard solutions containing a single rare earth element and for eight standard solutions containing an element other than rare earth elements. The selection of the emission lines and the algorithm of the present qualitative analysis were justified. (author)

  14. Elemental analysis using instrumental neutron activation analysis and inductively coupled plasma atomic emission spectrometry: a comparative study

    International Nuclear Information System (INIS)

    Chung, Yong Sam; Choi, Kwang Soon; Moon, Jong Hwa; Kim, Sun Ha; Lim, Jong Myoung; Kim, Young Jin; Quraishi, Shamshad Begum

    2003-05-01

    Elemental analyses for certified reference materials were carried out using instrumental neutron activation analysis and inductively coupled plasma-atomic emission spectrometry. Five Certified Reference Materials (CRM) were selected for the study on comparative analysis of environmental samples. The CRM are Soil (NIST SRM 2709), Coal fly ash (NIST SRM 1633a), urban dust (NIST SRM 1649a) and air particulate on filter media (NIST SRM 2783 and human hair (GBW 09101)

  15. Processing of spent Ni-MH batteries for the recovery of cobalt, nickel and rare earth elements bearing materials by means of a chemical and electrochemical sequential process

    Science.gov (United States)

    Delvasto, P.; Orta Rodríguez, R.; Blanco, S.

    2016-02-01

    Rechargeable Ni-MH batteries contain strategic metal values which are worth to be recovered. In the present work, a preliminary sequential chemical and electrochemical procedure is proposed, in order to reclaim materials bearing Ni, Co and rare earth elements (REE) from Ni-MH spent batteries. Initially, spent batteries are disassembled to separate the electrode materials (anode and cathode), which are then leached with an aqueous solution of 5w% sulphuric acid. The metal content of this solution is checked by atomic absorption spectrometry techniques. The obtained solution is pH-adjusted (with NaOH), until pH is between 4.0 and 4.3; then, it is heated up to 70°C to precipitate a rare earth elements sulphate (Nd, La, Pr, Ce), as determined by means of x-ray fluorescence techniques. The solids-free solution is then electrolyzed, in order to recover a Ni-Co alloy. The electrolysis conditions were established through a cyclic voltammetry technique.

  16. Comparison of Different Assembling Techniques Regarding Cost, Durability, and Ecology - A Survey of Multi-layer Wooden Panel Assembly Load-Bearing Construction Elements

    Directory of Open Access Journals (Sweden)

    Dietrich Buck

    2015-10-01

    Full Text Available Wood is a pure, sustainable, renewable material. The increasing use of wood for construction can improve its sustainability. There are various techniques to assemble multi-layer wooden panels into prefabricated, load-bearing construction elements. However, comparative market and economy studies are still scarce. In this study, the following assembling techniques were compared: laminating, nailing, stapling, screwing, stress laminating, doweling, dovetailing, and wood welding. The production costs, durability, and ecological considerations were presented. This study was based on reviews of published works and information gathered from 27 leading wood product manufacturing companies in six European countries. The study shows that the various techniques of assembling multi-layer wooden construction panel elements are very different. Cross laminated timber (CLT exhibited the best results in terms of cost and durability. With regard to ecological concerns, dovetailing is the best. Taking into account both durability and ecological considerations, wooden screw-doweling is the best. These alternatives give manufacturers some freedom of choice regarding the visibility of surfaces and the efficient use of lower-quality timber. CLT is the most cost-effective, is not patented, and is a well-established option on the market today.

  17. Coupling characteristics of the spun optical fiber with triple stress elements

    Science.gov (United States)

    Ji, Minning; Shang, Fengtao; Chen, Dandan

    2018-06-01

    An empirical formula related to the stress field distribution in the optical fiber with triple stress elements is proposed and proved. The possible intercoupling between the fundamental modes and the higher order modes is demonstrated. The transmission property of the spun optical fiber with triple stress elements is analyzed. The experimental data from a sample of the spun optical fiber with triple stress elements confirm the theoretical results very well.

  18. Load responsive hydrodynamic bearing

    Science.gov (United States)

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  19. Development of a finite element code to solve thermo-hydro-mechanical coupling and simulate induced seismicity.

    Science.gov (United States)

    María Gómez Castro, Berta; De Simone, Silvia; Rossi, Riccardo; Larese De Tetto, Antonia; Carrera Ramírez, Jesús

    2015-04-01

    Coupled thermo-hydro-mechanical modeling is essential for CO2 storage because of (1) large amounts of CO2 will be injected, which will cause large pressure buildups and might compromise the mechanical stability of the caprock seal, (2) the most efficient technique to inject CO2 is the cold injection, which induces thermal stress changes in the reservoir and seal. These stress variations can cause mechanical failure in the caprock and can also trigger induced earthquakes. To properly assess these effects, numerical models that take into account the short and long-term thermo-hydro-mechanical coupling are an important tool. For this purpose, there is a growing need of codes that couple these processes efficiently and accurately. This work involves the development of an open-source, finite element code written in C ++ for correctly modeling the effects of thermo-hydro-mechanical coupling in the field of CO2 storage and in others fields related to these processes (geothermal energy systems, fracking, nuclear waste disposal, etc.), and capable to simulate induced seismicity. In order to be able to simulate earthquakes, a new lower dimensional interface element will be implemented in the code to represent preexisting fractures, where pressure continuity will be imposed across the fractures.

  20. Timing and thermochemical constraints on multi-element mineralisation at the Nori/RA Cu-Mo-U prospect, Great Bear magmatic zone, Northwest Territories, Canada

    Science.gov (United States)

    Ootes, Luke; Goff, Steve; Jackson, Valerie A.; Gleeson, Sarah A.; Creaser, Robert A.; Samson, Iain M.; Evensen, Norman; Corriveau, Louise; Mumin, A. Hamid

    2010-08-01

    The timing of Cu-Mo-U mineralisation at the Nori/RA prospect in the Paleoproterozoic Great Bear magmatic zone has been investigated using Re-Os molybdenite and 40Ar-39Ar biotite geochronology. The Re-Os molybdenite ages presented are the first robust sulphide mineralisation ages derived from the Great Bear magmatic zone. Cu-Mo-U mineralisation is hosted in early to syn-deformational hydrothermal veins consisting of quartz and K-feldspar or more commonly tourmaline-biotite-quartz-K-feldspar, with associated wall-rock alteration assemblages being predominantly biotite. Sulphide and oxide minerals consist of chalcopyrite, molybdenite and uraninite with lesser pyrite and magnetite. Elevated light rare earth elements and tungsten concentrations associated with the Cu-Mo-U mineralisation have also been reported at the prospect by previous workers. Molybdenite and uraninite occur intimately in dravitic tourmaline growth zones and at grain margins, attesting to their syngenetic nature (with respect to hydrothermal veining). Two molybdenite separates yield Re-Os model ages of 1,874.4 ± 8.7 (2 σ) and 1,872.4 ± 8.8 Ma (2 σ) with a weighted average model age of 1,873.4 ± 6.1 Ma (2 σ). Laser step heating of biotite from the marginal alteration of the wall-rock adjacent to the veins yields a 40Ar-39Ar maximum cooling age of 1,875 ± 8 Ma (MSWD = 3.8; 2 σ), indistinguishable from the Re-Os molybdenite model age and a previously dated ‘syn-tectonic’ aplitic dyke in the region. Dravitic tourmaline hosts abundant primary liquid-vapour-solid-bearing fluid inclusions. Analytical results indicate liquid-vapour homogenisation at >260°C constraining the minimum temperature of mineralisation. The solids, which are possibly trapped, did not homogenise with the liquid-vapour by 400°C. Salinities in the inclusions are variable. Raman spectra identify that at least some of the solids are calcite and anhydrite. Raman spectra also confirm the vapour phases contain some CO2; whereas

  1. A coupled boundary element-finite difference solution of the elliptic modified mild slope equation

    DEFF Research Database (Denmark)

    Naserizadeh, R.; Bingham, Harry B.; Noorzad, A.

    2011-01-01

    The modified mild slope equation of [5] is solved using a combination of the boundary element method (BEM) and the finite difference method (FDM). The exterior domain of constant depth and infinite horizontal extent is solved by a BEM using linear or quadratic elements. The interior domain...

  2. A Coupled Helicopter Rotor/Fuselage Dynamics Model Using Finite Element Multi-body

    Directory of Open Access Journals (Sweden)

    Cheng Qi-you

    2016-01-01

    Full Text Available To develop a coupled rotor/flexible fuselage model for vibration reduction studies, the equation of coupled rotor-fuselage is set up based on the theory of multi-body dynamics, and the dynamic analysis model is established with the software MSC.ADMAS and MSC.NASTRAN. The frequencies and vibration acceleration responses of the system are calculated with the model of coupled rotor-fuselage, and the results are compared with those of uncoupled modeling method. Analysis results showed that compared with uncoupled model, the dynamic characteristic obtained by the model of coupled rotor-fuselage are some different. The intrinsic frequency of rotor is increased with the increase of rotational velocities. The results also show that the flying speed has obvious influence on the vibration acceleration responses of the fuselage. The vibration acceleration response in the vertical direction is much higher at the low speed and high speed flight conditions.

  3. Tilting-Pad Journal Bearings with Active Lubrication Applied as Calibrated Shakers: Theory and Experiment

    DEFF Research Database (Denmark)

    Cerda Varela, Alejandro Javier; Santos, Ilmar

    2014-01-01

    In recent years, a continuous research effort has transformed the conventional tilting-pad journal bearing into a mechatronic machine element. The addition of electromechanical elements provides the possibility of generating controllable forces over the rotor as a function of a suitable control...... directly into the bearing clearance. The injected flow is controlled by means of a servovalve. The theoretical model includes the dynamics of servovalves and pipelines using a lumped parameter approach, whereas the coupling between the hydraulic system and the bearing oil film is modeled using a modified...

  4. Investigations on the direct introduction of cigarette smoke for trace elements analysis by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Chang, Michael J.; Naworal, John D.; Walker, Kathleen; Connell, Chris T.

    2003-01-01

    Direct introduction of mainstream cigarette smoke into an inductively coupled plasma mass spectrometry (ICP-MS) has been investigated with respect to its feasibility for on-line analysis of trace elements. An automated apparatus was designed and built interfacing a smoking machine with an ICP-MS for smoke generation, collection, injection and analysis. Major and minor elements present in the particulate phase and the gas phase of mainstream cigarette smoke of 2R4F reference cigarettes have been qualitatively identified by examination of their full mass spectra. This method provides a rapid-screening analysis of the transfer of trace elements into mainstream smoke during cigarette combustion. A full suite of elements present in the whole cigarette smoke has been identified, including As, B, Ba, Br, Cd, Cl, Cs, Cu, Hg, I, K, Li, Mn, Na, Pb, Rb, Sb, Sn, Tl and Zn. Of these elements, the major portions of B, Ba, Cs, Cu, K, Li, Mn, Na, Pb, Rb, Sn, Tl and Zn are present in the particulate phase, whereas the major portion of Hg is present in the gas phase. As, Br, Cd, Cl, I and Sb exist in a distribution between the gas phase and the particulate phase. Depending on the element, the precision of measurement ranges from 5 to 25% in terms of relative standard deviation of peak height and peak area, based on the fourth puff of 2R4F mainstream cigarette smoke analyzed in five smoking replicates

  5. Determination of daily intake of elements from Philippine total diet samples using inductively coupled plasma-atomic emission spectrometry

    International Nuclear Information System (INIS)

    Leon, G.C. de; Shiraishi, K.; Kawamura, H.; Igaraishi, Y.; Palattao, M.V.; Azanon, E.M.

    1990-10-01

    Total diet samples were analyzed for major elements (Na, K, Ca, Mg, P) and some minor trace elements (Fe, Zn, Mn, Al, Sr, Cu, Ba, Yt) using inductively coupled plasma-atomic emission spectrometry (ICP-AES). Samples analyzed were classified into sex and age groups. Results for some elements (Na, K, Mg, Zn, Cu, Mn) were compared with values from Bataan dietary survey calculated using the Philippine composition table. Exceot for Na, analytical results were similar to calculated values. Analytical results for Ca and Fe were also compared with the values from Food and Nutrition Research Institute. In general, values obtained in the study were lower than the FNRI values. Comparison of the analytical and calculated results with the Japanese and ICRP data showed that Philippine values were lower than foreign values. (Auth.). 22 refs., 9 tabs

  6. Total and species-specific quantitative analyses of trace elements in sediment by isotope dilution inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Inagaki, Kazumi; Takatsu, Akiko; Yarita, Takashi; Okamoto, Kensaku; Chiba, Koichi

    2009-01-01

    Isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) is one of the reliable methods for total and species-specific quantitative analysis of trace elements. However, several technical problems (e.g. spectral interference caused from sample constituents) should be overcome to obtain reliable analytical results when environmental samples are analyzed by ID-ICP-MS. In our laboratory, various methods based on ID-ICP-MS have been investigated for reliable quantitative analyses of trace elements in environmental samples. In this paper, coprecipitate separation/ID-ICP-MS for the determination of trace elements in sediment, cation exchange disk filtration/ID-ICP-MS for the determination of selenium in sediment, species-specific ID-ICP-MS using 118 Sn/labeled organotin compounds for the determination of butyltins and phenyltins, and the application of the ID-ICP-MS methods to the certification of sediment reference materials are described. (author)

  7. Space-time coupled spectral/hp least-squares finite element formulation for the incompressible Navier-Stokes equations

    International Nuclear Information System (INIS)

    Pontaza, J.P.; Reddy, J.N.

    2004-01-01

    We consider least-squares finite element models for the numerical solution of the non-stationary Navier-Stokes equations governing viscous incompressible fluid flows. The paper presents a formulation where the effects of space and time are coupled, resulting in a true space-time least-squares minimization procedure, as opposed to a space-time decoupled formulation where a least-squares minimization procedure is performed in space at each time step. The formulation is first presented for the linear advection-diffusion equation and then extended to the Navier-Stokes equations. The formulation has no time step stability restrictions and is spectrally accurate in both space and time. To allow the use of practical C 0 element expansions in the resulting finite element model, the Navier-Stokes equations are expressed as an equivalent set of first-order equations by introducing vorticity as an additional independent variable and the least-squares method is used to develop the finite element model of the governing equations. High-order element expansions are used to construct the discrete model. The discrete model thus obtained is linearized by Newton's method, resulting in a linear system of equations with a symmetric positive definite coefficient matrix that is solved in a fully coupled manner by a preconditioned conjugate gradient method in matrix-free form. Spectral convergence of the L 2 least-squares functional and L 2 error norms in space-time is verified using a smooth solution to the two-dimensional non-stationary incompressible Navier-Stokes equations. Numerical results are presented for impulsively started lid-driven cavity flow, oscillatory lid-driven cavity flow, transient flow over a backward-facing step, and flow around a circular cylinder; the results demonstrate the predictive capability and robustness of the proposed formulation. Even though the space-time coupled formulation is emphasized, we also present the formulation and numerical results for least

  8. Development of finite element code for the analysis of coupled thermo-hydro-mechanical behaviors of saturated-unsaturated medium

    International Nuclear Information System (INIS)

    Ohnishi, Y.; Shibata, H.; Kobayashi, A.

    1985-01-01

    A model is presented which describes fully coupled thermo-hydro-mechanical behavior of porous geologic medium. The mathematical formulation for the model utilizes the Biot theory for the consolidation and the energy balance equation. The medium is in the condition of saturated-unsaturated flow, then the free surfaces are taken into consideration in the model. The model, incorporated in a finite element numerical procedure, was implemented in a two-dimensional computer code. The code was developed under the assumptions that the medium is poro-elastic and in plane strain condition; water in the ground does not change its phase; heat is transferred by conductive and convective flow. Analytical solutions pertaining to consolidation theory for soils and rocks, thermoelasticity for solids and hydrothermal convection theory provided verification of stress and fluid flow couplings, respectively in the coupled model. Several types of problems are analyzed. The one is a study of some of the effects of completely coupled thermo-hydro-mechanical behavior on the response of a saturated-unsaturated porous rock containing a buried heat source. Excavation of an underground opening which has radioactive wastes at elevated temperatures is modeled and analyzed. The results shows that the coupling phenomena can be estimated at some degree by the numerical procedure. The computer code has a powerful ability to analyze of the repository the complex nature of the repository

  9. Coupling multipoint flux mixed finite element methodswith continuous Galerkin methods for poroelasticity

    KAUST Repository

    Wheeler, Mary; Xue, Guangri; Yotov, Ivan

    2013-01-01

    We study the numerical approximation on irregular domains with general grids of the system of poroelasticity, which describes fluid flow in deformable porous media. The flow equation is discretized by a multipoint flux mixed finite element method

  10. Simulation of fluid-structure interaction in micropumps by coupling of two commercial finite element programs

    Science.gov (United States)

    Klein, Andreas; Gerlach, Gerald

    1998-09-01

    This paper deals with the simulation of the fluid-structure interaction phenomena in micropumps. The proposed solution approach is based on external coupling of two different solvers, which are considered here as `black boxes'. Therefore, no specific intervention is necessary into the program code, and solvers can be exchanged arbitrarily. For the realization of the external iteration loop, two algorithms are considered: the relaxation-based Gauss-Seidel method and the computationally more extensive Newton method. It is demonstrated in terms of a simplified test case, that for rather weak coupling, the Gauss-Seidel method is sufficient. However, by simply changing the considered fluid from air to water, the two physical domains become strongly coupled, and the Gauss-Seidel method fails to converge in this case. The Newton iteration scheme must be used instead.

  11. A study on high speed coupling design for wind turbine using a finite element analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyoung Woo; Kang, Jong Hun [Dept. of Mechatronics Engineering, Jungwon University, Geosan (Korea, Republic of); Han, Jeong Young [Pusan Educational Center for Computer Aided Machine Design, Pusan University, Busan (Korea, Republic of)

    2016-08-15

    The purpose of this study is to design a high speed coupling for 3 MW wind turbines and evaluate its structural stability. A basic analysis was performed to assess the structural stability of two materials, SPS6 steel plate and a composite material (Glass7628, Glass/Epoxy), in relation to misalignment in the axial and radial directions. The entire model was analyzed for a high speed coupling based on the SPS6 steel plate, which was found to have higher stability among the two materials, and safety factors were estimated for various levels of power delivery. To test the proposed high speed coupling design, a performance test was carried out to verify the stability of the final product.

  12. A study on high speed coupling design for wind turbine using a finite element analysis

    International Nuclear Information System (INIS)

    Lee, Hyoung Woo; Kang, Jong Hun; Han, Jeong Young

    2016-01-01

    The purpose of this study is to design a high speed coupling for 3 MW wind turbines and evaluate its structural stability. A basic analysis was performed to assess the structural stability of two materials, SPS6 steel plate and a composite material (Glass7628, Glass/Epoxy), in relation to misalignment in the axial and radial directions. The entire model was analyzed for a high speed coupling based on the SPS6 steel plate, which was found to have higher stability among the two materials, and safety factors were estimated for various levels of power delivery. To test the proposed high speed coupling design, a performance test was carried out to verify the stability of the final product

  13. Determination of the elemental composition of ferromanganese formations certified reference materials by mass-spectrometry with inductively coupled plasma

    Directory of Open Access Journals (Sweden)

    N. V. Zarubina

    2014-01-01

    Full Text Available Contents of 41 elements in the Russian standard samples of ferromanganese nodules OOPE 601, OOPE 602, OOPE 603 and ore crust OOPE 604 were identified by mass-spectrometry with inductively-coupled plasma. Content of W was firstly presented in the sample OOPE-603. Relative standard deviation for most elements was in the range of 3-10%. A description of ICP-MS technique including sample preparation procedure and other instrumental parameters were given as well as analysis of ferromanganese nodules standard samples NOD-A-1 and NOD-P-1 of U.S. Geological Survey was demonstrated for validation. Normalized to chondrite distribution curves of REE in the studied samples were shown as an indicator of the internal consistency offound concentrations. The available literature data on the content of a wide range of elements and its comparison with the matter obtained by us was produced. Measured contents of elements in the established CRM may be useful in the analytical practice to evaluate precision of results. There is a lack of relevant information on a variety of geochemically important elements in the Russian standard samples of OOPE series and the new data can be taken into account in their certification.

  14. Application of slurry nebulization to trace elemental analysis of some biological samples by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Mochizuki, T.; Sakashita, A.; Iwata, H.; Ishibashi, Y.; Gunji, N.

    1991-01-01

    The application of slurry nebulization/inductively coupled plasma mass spectrometry (ICP-MS) to trace elemental analysis of biological samples has been investigated. Three standard samples of the National Institute of Standards and Technology (NIST) were dispersed in 1% aqueous Triton X-100 solution by grinding with a planetary micronizing mill. The resulting slurries were nebulized into an ICP without any additional treatments. The 1% (m/v) slurry of the NIST bovine liver showed no significant influence on cone blockage and signal suppression/enhancement. Detection limit, precision and accuracy were discussed for the determination of 24 elements of interest in bovine liver, rice flour and pine needles. Detection limits ranged from 0.0001 μg g -1 for U to 0.52 μg g -1 for Zn at the effective integrating time of 10 s. For high mass elements, low blank values were obtained, yielding excellent limits ( -1 ). Acceptable accuracy and precision were obtained for most of the elements in the NIST bovine liver and rice flour, even for the volatile elements, such as As, Se and Br. However, relatively poor accuracy was obtained for the analysis of pine needles. (orig.)

  15. Couplings

    Science.gov (United States)

    Stošić, Dušan; Auroux, Aline

    Basic principles of calorimetry coupled with other techniques are introduced. These methods are used in heterogeneous catalysis for characterization of acidic, basic and red-ox properties of solid catalysts. Estimation of these features is achieved by monitoring the interaction of various probe molecules with the surface of such materials. Overview of gas phase, as well as liquid phase techniques is given. Special attention is devoted to coupled calorimetry-volumetry method. Furthermore, the influence of different experimental parameters on the results of these techniques is discussed, since it is known that they can significantly influence the evaluation of catalytic properties of investigated materials.

  16. Determination of refractive and volatile elements in sediment using laser ablation inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Duodu, Godfred Odame [School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), 2 George St, 4001, QLD (Australia); Goonetilleke, Ashantha [School of Civil Engineering and Built Environment, Science and Engineering Faculty, Queensland University of Technology (QUT), 2 George St, 4001, QLD (Australia); Allen, Charlotte [Institute for Future Environments, Queensland University of Technology (QUT), 2 George St, 4001, QLD (Australia); Ayoko, Godwin A., E-mail: g.ayoko@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology (QUT), 2 George St, 4001, QLD (Australia)

    2015-10-22

    Wet-milling protocol was employed to produce pressed powder tablets with excellent cohesion and homogeneity suitable for laser ablation (LA) analysis of volatile and refractive elements in sediment. The influence of sample preparation on analytical performance was also investigated, including sample homogeneity, accuracy and limit of detection. Milling in volatile solvent for 40 min ensured sample is well mixed and could reasonably recover both volatile (Hg) and refractive (Zr) elements. With the exception of Cr (−52%) and Nb (+26%) major, minor and trace elements in STSD-1 and MESS-3 could be analysed within ±20% of the certified values. Comparison of the method with total digestion method using HF was tested by analysing 10 different sediment samples. The laser method recovers significantly higher amounts of analytes such as Ag, Cd, Sn and Sn than the total digestion method making it a more robust method for elements across the periodic table. LA-ICP-MS also eliminates the interferences from chemical reagents as well as the health and safety risks associated with digestion processes. Therefore, it can be considered as an enhanced method for the analysis of heterogeneous matrices such as river sediments. - Highlights: • Wet milling was used to produce pressed tablet sediment for LA-ICP-MS analysis. • Milling was effective for refractive elements with narrow range of particle size. • This is the first use of LA-ICP-MS for Hg analysis in sediment samples. • Acceptable accuracy and precision were obtained for most of the elements studied. • Detection limits down to parts per trillion were observed for some elements.

  17. Multi-elemental analysis of aqueous geochemical samples by quadrupole inductively coupled plasma-mass spectrometry (ICP-MS)

    Science.gov (United States)

    Wolf, Ruth E.; Adams, Monique

    2015-01-01

    Typically, quadrupole inductively coupled plasma-mass spectrometry (ICP-MS) is used to determine as many as 57 major, minor, and trace elements in aqueous geochemical samples, including natural surface water and groundwater, acid mine drainage water, and extracts or leachates from geological samples. The sample solution is aspirated into the inductively coupled plasma (ICP) which is an electrodeless discharge of ionized argon gas at a temperature of approximately 6,000 degrees Celsius. The elements in the sample solution are subsequently volatilized, atomized, and ionized by the ICP. The ions generated are then focused and introduced into a quadrupole mass filter which only allows one mass to reach the detector at a given moment in time. As the settings of the mass analyzer change, subsequent masses are allowed to impact the detector. Although the typical quadrupole ICP-MS system is a sequential scanning instrument (determining each mass separately), the scan speed of modern instruments is on the order of several thousand masses per second. Consequently, typical total sample analysis times of 2–3 minutes are readily achievable for up to 57 elements.

  18. Ion-microprobe measurements of Mg, Ca, Ti and Fe isotopic ratios and trace element abundance in hibonite-bearing inclusions in primitive meteorites

    International Nuclear Information System (INIS)

    Fahey, A.J.

    1988-01-01

    This thesis reports the isotopic abundances of Mg, Ca, and Ti and rare earth element (REE) abundances in 19 hibonite-bearing inclusions from primative meteorites. The isotopic ratios of Fe were measured in one of the samples, Lance HH-1. These measurements were made by means of secondary ion mass spectrometry (CAMECA IMS-3f). The novel hardware and software developments that made this work possible are described in detail. The samples were studied in thin section in order to investigate the relationship between the inclusions and their mineralogical environments. Inclusions from a number of different meteorites, specifically, Mighei, Murray, Murchison, Lance, Efremovka, Vigarano, Qingzhen, Dhajala, and Semarkona, were studied. The isotopes of Ca and Ti show large and correlated abundance anomalies in their most neutron-rich isotopes, 48 Ca and 50 Ti. The largest anomalies among the samples studied here are in the Murray inclusion MY-F6, with a 4.6% deficit in 48 Ca and a 5.2% deficit in 50 Ti, and Lance HH-1, with 3.3% and 6.0% deficits in 48 Ca and 50 Ti respectively. Correlated excesses of 48 Ca and 50 Ti, up to 2.4% and 1.4% respectively, are found in some other samples studied here. The fact that there is a correlation of isotopic anomalies in two different elements is clear evidence for a nucleosynthetic origin of these effects. Various possibilities for the origin of these isotopic anomalies are discussed and it is shown that a Cosmic Chemical Memory-like model of the incomplete mixing of dust grains from one or several supernovae is sufficient to explain the data. Magnesium isotopes show excesses of 26 Mg, attributable to the in-situ decay of 26 Al, in 7 of these inclusions

  19. Towards better monitoring of technology critical elements in Europe: Coupling of natural and anthropogenic cycles.

    Science.gov (United States)

    Nuss, Philip; Blengini, Gian Andrea

    2018-02-01

    The characterization of elemental cycles has a rich history in biogeochemistry. Well known examples include the global carbon cycle, or the cycles of the 'grand nutrients' nitrogen, phosphorus, and sulfur. More recently, efforts have increased to better understand the natural cycling of technology critical elements (TCEs), i.e. elements with a high supply risk and economic importance in the EU. On the other hand, tools such as material-flow analysis (MFA) can help to understand how substances and goods are transported and accumulated in man-made technological systems ('anthroposphere'). However, to date both biogeochemical cycles and MFA studies suffer from narrow system boundaries, failing to fully illustrate relative anthropogenic and natural flow magnitude and the degree to which human activity has perturbed the natural cycling of elements. We discuss important interconnections between natural and anthropogenic cycles and relevant EU raw material dossiers. Increased integration of both cycles could help to better capture the transport and fate of elements in nature including their environmental/human health impacts, highlight potential future material stocks in the anthroposphere (in-use stocks) and in nature (e.g., in soils, tailings, or mining wastes), and estimate anticipated emissions of TCEs to nature in the future (based on dynamic stock modeling). A preliminary assessment of natural versus anthropogenic element fluxes indicates that anthropogenic fluxes induced by the EU-28 of palladium, platinum, and antimony (as a result of materials uses) might be greater than the respective global natural fluxes. Increased combination of MFA and natural cycle data at EU level could help to derive more complete material cycles and initiate a discussion between the research communities of biogeochemists and material flow analysts to more holistically address the issues of sustainable resource management. Copyright © 2017 The Authors. Published by Elsevier B.V. All

  20. Coupling multipoint flux mixed finite element methodswith continuous Galerkin methods for poroelasticity

    KAUST Repository

    Wheeler, Mary

    2013-11-16

    We study the numerical approximation on irregular domains with general grids of the system of poroelasticity, which describes fluid flow in deformable porous media. The flow equation is discretized by a multipoint flux mixed finite element method and the displacements are approximated by a continuous Galerkin finite element method. First-order convergence in space and time is established in appropriate norms for the pressure, velocity, and displacement. Numerical results are presented that illustrate the behavior of the method. © Springer Science+Business Media Dordrecht 2013.

  1. Quantification of plasmodesmatal endoplasmic reticulum coupling between sieve elements and companion cells using fluorescence redistribution after photobleaching

    DEFF Research Database (Denmark)

    Martens, Helle; Roberts, Alison G.; Oparka, Karl J.

    2006-01-01

    retrieval along the pathway is an integral component of phloem function. GFP fluorescence was limited to CCs where it was visualized as a well-developed ER network in close proximity to the plasma membrane. ER coupling between CC and SEs was tested in wild-type tobacco using an ER-specific fluorochrome......Transgenic tobacco (Nicotiana tabacum) was studied to localize the activity of phloem loading during development and to establish whether the endoplasmic reticulum (ER) of the companion cell (CC) and the sieve element (SE) reticulum is continuous by using a SUC2 promoter-green fluorescent protein...... and fluorescence redistribution after photobleaching (FRAP), and showed that the ER is continuous via pore-plasmodesma units. ER coupling between CC and SE was quantified by determining the mobile fraction and half-life of fluorescence redistribution and compared with that of other cell types. In all tissues...

  2. Third-Order Spectral Techniques for the Diagnosis of Motor Bearing Condition Using Artificial Neural Networks

    Science.gov (United States)

    Yang, D.-M.; Stronach, A. F.; MacConnell, P.; Penman, J.

    2002-03-01

    This paper addresses the development of a novel condition monitoring procedure for rolling element bearings which involves a combination of signal processing, signal analysis and artificial intelligence methods. Seven approaches based on power spectrum, bispectral and bicoherence vibration analyses are investigated as signal pre-processing techniques for application in the diagnosis of a number of induction motor rolling element bearing conditions. The bearing conditions considered are a normal bearing and bearings with cage and inner and outer race faults. The vibration analysis methods investigated are based on the power spectrum, the bispectrum, the bicoherence, the bispectrum diagonal slice, the bicoherence diagonal slice, the summed bispectrum and the summed bicoherence. Selected features are extracted from the vibration signatures so obtained and these are used as inputs to an artificial neural network trained to identify the bearing conditions. Quadratic phase coupling (QPC), examined using the magnitude of bispectrum and bicoherence and biphase, is shown to be absent from the bearing system and it is therefore concluded that the structure of the bearing vibration signatures results from inter-modulation effects. In order to test the proposed procedure, experimental data from a bearing test rig are used to develop an example diagnostic system. Results show that the bearing conditions examined can be diagnosed with a high success rate, particularly when using the summed bispectrum signatures.

  3. Coupled convective and conductive heat transfer by up-wind finite element method

    International Nuclear Information System (INIS)

    Kushwaha, H.S.

    1981-01-01

    Some of concepts relating to finite element formulation of the Navier-Stoke's equations using mixed formulation and Penality formulation have been discussed. The two different approaches for solution of nonlinear differential equations for two different types of formulation have been described. Incremental Newton Raphson method can also be applied to mixed formulation. (author)

  4. Determination of refractive and volatile elements in sediment using laser ablation inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Duodu, Godfred Odame; Goonetilleke, Ashantha; Allen, Charlotte; Ayoko, Godwin A

    2015-10-22

    Wet-milling protocol was employed to produce pressed powder tablets with excellent cohesion and homogeneity suitable for laser ablation (LA) analysis of volatile and refractive elements in sediment. The influence of sample preparation on analytical performance was also investigated, including sample homogeneity, accuracy and limit of detection. Milling in volatile solvent for 40 min ensured sample is well mixed and could reasonably recover both volatile (Hg) and refractive (Zr) elements. With the exception of Cr (-52%) and Nb (+26%) major, minor and trace elements in STSD-1 and MESS-3 could be analysed within ±20% of the certified values. Comparison of the method with total digestion method using HF was tested by analysing 10 different sediment samples. The laser method recovers significantly higher amounts of analytes such as Ag, Cd, Sn and Sn than the total digestion method making it a more robust method for elements across the periodic table. LA-ICP-MS also eliminates the interferences from chemical reagents as well as the health and safety risks associated with digestion processes. Therefore, it can be considered as an enhanced method for the analysis of heterogeneous matrices such as river sediments. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Bacterial disproportionation of elemental sulfur coupled to chemical reduction of iron or manganese

    DEFF Research Database (Denmark)

    Thamdrup, Bo; Finster, Kai; Hansen, Jens Würgler

    1993-01-01

    A new chemolithotrophic bacterial metabolism was discovered in anaerobic marine enrichment cultures. Cultures in defined medium with elemental sulfur (S) and amorphous ferric hydroxide (FeOOH) as sole substrates showed intense formation of sulfate. Furthermore, precipitation of ferrous sulfide an...

  6. Leaching Process of Rare Earth Elements, Gallium and Niobium in a Coal-Bearing Strata-Hosted Rare Metal Deposit—A Case Study from the Late Permian Tuff in the Zhongliangshan Mine, Chongqing

    OpenAIRE

    Jianhua Zou; Heming Tian; Zhen Wang

    2017-01-01

    The tuff, a part of coal-bearing strata, in the Zhongliangshan coal mine, Chongqing, southwestern China, hosts a rare metal deposit enriched in rare earth elements (REE), Ga and Nb. However, the extraction techniques directly related to the recovery of rare metals in coal-bearing strata have been little-studied in the literature. The purpose of this paper is to investigate the extractability of REE, Ga and Nb in the tuff in the Zhongliangshan mine using the alkaline sintering-water immersion-...

  7. Measuring the Higgs Boson Self Coupling at the LHC and Finite Top Mass Matrix Elements

    CERN Document Server

    Baur, Ulrich; Rainwater, D L; Baur, Uli; Plehn, Tilman; Rainwater, David

    2002-01-01

    Inclusive Standard Model Higgs boson pair production and subsequent decay to same-sign dileptons via weak gauge W bosons at the CERN Large Hadron Collider has the capability to determine the Higgs boson self-coupling, lambda. The large top quark mass limit is found not to be a good approximation for the signal if one wishes to utilize differential distributions in the analysis. We find that it should be possible at the LHC with design luminosity to establish that the Standard Model Higgs boson has a non-zero self-coupling and that lambda/lambda(SM) can be restricted to a range of 0--3.7 at 95% confidence level if its mass is between 150 and 200 GeV.

  8. Accuracy and Precision in Elemental Analysis of Environmental Samples using Inductively Coupled Plasma-Atomic Emission Spectrometry

    International Nuclear Information System (INIS)

    Quraishi, Shamsad Begum; Chung, Yong-Sam; Choi, Kwang Soon

    2005-01-01

    Inductively Coupled Plasma-Atomic Emission Spectrometry followed by micro-wave digestion have been performed on different environmental Certified Reference Materials (CRMs). Analytical results show that accuracy and precision in ICP-AES analysis were acceptable and satisfactory in case of soil and hair CRM samples. The relative error of most of the elements in these two CRMs is within 10% with few exceptions and coefficient of variation is also less than 10%. Z-score as an analytical performance was also within the acceptable range (±2). ICP-AES was found as an inadequate method for Air Filter CRM due to incomplete dissolution, low concentration of elements and very low mass of the sample. However, real air filter sample could have been analyzed with high accuracy and precision by increasing sample mass during collection. (author)

  9. Standard test method for determining elements in waste streams by inductively coupled plasma-atomic emission spectroscopy

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    This test method covers the determination of trace, minor, and major elements in waste streams by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) following an acid digestion of the specimen. Waste streams from manufacturing processes of nuclear and nonnuclear materials can be analyzed. This test method is applicable to the determination of total metals. Results from this test method can be used to characterize waste received by treatment facilities and to formulate appropriate treatment recipes. The results are also usable to process control within waste treatment facilities. This test method is applicable only to waste streams that contain radioactivity levels which do not require special personnel or environmental protection. A list of the elements determined in waste streams and the corresponding lower reporting limit is included

  10. Determination of trace elements in petroleum products by inductively coupled plasma techniques: A critical review

    International Nuclear Information System (INIS)

    Sánchez, Raquel; Todolí, José Luis; Lienemann, Charles-Philippe; Mermet, Jean-Michel

    2013-01-01

    The fundamentals, applications and latter developments of petroleum products analysis through inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) are revisited in the present bibliographic survey. Sample preparation procedures for the direct analysis of fuels by using liquid sample introduction systems are critically reviewed and compared. The most employed methods are sample dilution, emulsion or micro-emulsion preparation and sample decomposition. The first one is the most widely employed due to its simplicity. Once the sample has been prepared, an organic matrix is usually present. The performance of the sample introduction system (i.e., nebulizer and spray chamber) depends strongly upon the nature and properties of the solution finally obtained. Many different devices have been assayed and the obtained results are shown. Additionally, samples can be introduced into the plasma by using an electrothermal vaporization (ETV) device or a laser ablation system (LA). The recent results published in the literature showing the feasibility, advantages and drawbacks of latter alternatives are also described. Therefore, the main goal of the review is the discussion of the different approaches developed for the analysis of crude oil and its derivates by inductively coupled plasma (ICP) techniques. - Highlights: • Analysis of petroleum products by inductively coupled plasma techniques is revisited. • Fundamental studies are included together with reports dealing with applications. • Conventional and non-conventional sample introduction methods are considered. • Sample preparation methods are critically compared and described

  11. Modeling guided wave excitation in plates with surface mounted piezoelectric elements: coupled physics and normal mode expansion

    Science.gov (United States)

    Ren, Baiyang; Lissenden, Cliff J.

    2018-04-01

    Guided waves have been extensively studied and widely used for structural health monitoring because of their large volumetric coverage and good sensitivity to defects. Effectively and preferentially exciting a desired wave mode having good sensitivity to a certain defect is of great practical importance. Piezoelectric discs and plates are the most common types of surface-mounted transducers for guided wave excitation and reception. Their geometry strongly influences the proportioning between excited modes as well as the total power of the excited modes. It is highly desirable to predominantly excite the selected mode while the total transduction power is maximized. In this work, a fully coupled multi-physics finite element analysis, which incorporates the driving circuit, the piezoelectric element and the wave guide, is combined with the normal mode expansion method to study both the mode tuning and total wave power. The excitation of circular crested waves in an aluminum plate with circular piezoelectric discs is numerically studied for different disc and adhesive thicknesses. Additionally, the excitation of plane waves in an aluminum plate, using a stripe piezoelectric element is studied both numerically and experimentally. It is difficult to achieve predominant single mode excitation as well as maximum power transmission simultaneously, especially for higher order modes. However, guidelines for designing the geometry of piezoelectric elements for optimal mode excitation are recommended.

  12. Visualizing fossilization using laser ablation-inductively coupled plasma-mass spectrometry maps of trace elements in Late Cretaceous bones

    Science.gov (United States)

    Koenig, A.E.; Rogers, R.R.; Trueman, C.N.

    2009-01-01

    Elemental maps generated by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) provide a previously unavailable high-resolution visualization of the complex physicochemical conditions operating within individual bones during the early stages of diagenesis and fossilization. A selection of LA-ICP-MS maps of bones collected from the Late Cretaceous of Montana (United States) and Madagascar graphically illustrate diverse paths to recrystallization, and reveal unique insights into geochemical aspects of taphonomic history. Some bones show distinct gradients in concentrations of rare earth elements and uranium, with highest concentrations at external bone margins. Others exhibit more intricate patterns of trace element uptake related to bone histology and its control on the flow paths of pore waters. Patterns of element uptake as revealed by LA-ICP-MS maps can be used to guide sampling strategies, and call into question previous studies that hinge upon localized bulk samples of fossilized bone tissue. LA-ICP-MS maps also allow for comparison of recrystallization rates among fossil bones, and afford a novel approach to identifying bones or regions of bones potentially suitable for extracting intact biogeochemical signals. ?? 2009 Geological Society of America.

  13. Microwave assisted digestion of atmospheric aerosol samples followed by inductively coupled plasma mass spectrometry determination of trace elements

    Energy Technology Data Exchange (ETDEWEB)

    Swami, K.; Judd, C.D.; Orsini, J.; Yang, K.X. [New York State Dept. of Health, Albany, NY (United States). Wadsworth Center for Labs. and Research; Husain, L. [New York State Dept. of Health, Albany, NY (United States). Wadsworth Center for Labs. and Research; Dept. of Environmental Health and Toxicology, State Univ. of New York, Albany (United States)

    2001-01-01

    A microwave digestion method in a closed vessel was developed for the determination of trace metals in atmospheric aerosols using inductively coupled plasma mass spectrometry (ICP-MS). A recovery study for the elements V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Cd, Sb, and Pb was conducted using multi-elemental standard solutions, NIST 1633b Trace Elements in Coal Fly Ash, and NIST 1648 Urban Particulate Matter. A simple digestion method using only HNO{sub 3}/H{sub 2}O{sub 2}gave good recoveries (90%-108%) for all elements except Cr in SRM 1648, but yielded low recoveries for SRM 1633b. A more robust method using HNO {sub 3}/H {sub 2}O {sub 2}/HF/H {sub 3}BO {sub 3} yielded higher recoveries (82%-103%) for the lighter elements (V - Zn) in SRM 1633b, and improved the Cr recovery in SRM 1648, but decreased the Se recovery in both SRMs. A comparative analysis of aerosol samples obtained at a remote mountain location Nathiagali, Pakistan (2.5 km above mean sea level), and Mayville, New York, downwind from the highly industrialized Midwestern United States, was carried out using Instrumental Neutron Activation Analysis (INAA) for the elements Cr, Mn, Fe, Co, Zn, As, Se, and Sb. The simple digestion method yielded excellent agreement for Cr, Fe, Zn, As, Se, and Sb, with slopes of the ICP-MS vs. INAA regressions of 0.90-1.00 and R {sup 2} values of 0.96-1.00. The regressions for Mn and Co had slopes of 0.82 and 0.84 with R {sup 2} values of 0.83 and 0.82, respectively. Addition of HF/H {sub 3}BO {sub 3} did not improve the correlation for any of the elements and degraded the precision somewhat. The technique provides sensitivity and accuracy for trace elements in relatively small aerosol samples used in atmospheric chemistry studies related to SO {sub 2} oxidation in cloud droplets. The ability to determine concentrations of a very large number of elements from a single analysis will permit source apportionment of various trace pollutants and hence strategies to control the

  14. Advantages and disadvantages of application of inductively coupled plasma mass spectrometry for analysis of trace elements

    International Nuclear Information System (INIS)

    Kovacs, Bela; Borbely, Maria

    2011-01-01

    In this paper the advantages and disadvantages are detailed, moreover special interference effects of the examined elements are evaluated. The detection limits of different ICP-MS instruments are compared. As a result of our research work various solutions are proposed for multielement analysis (e.g. Se, I, Co, As, Te, Cd, Pb and Cr) of the above various samples to reach more accurate and more precise results using ICP-MS instrument

  15. Development of a coupled lattice Boltzmann and finite element method for fluid-structure interaction problems

    International Nuclear Information System (INIS)

    Jo, Jong Chull; Roh, Kyung Wan; Jhung, Myung Jo

    2006-12-01

    During this work period, a preliminary research has been conducted in the three different and related areas as stated in the proposal: literature survey, preliminary feasibility study of LBM and FEM coupling for FSI problems, and benchmark problems. As far as the literature review was concerned, approximately one hundred articles were found for the LBM techniques and critical review has been performed. The reviewed articles were classified into several topics that are useful for a subsequent development of the proposed computer program. Those topics included immiscible multicomponent flows, flow with energy transport, coupled multi-physics applications, application of the boundary conditions, irregular lattices, and turbulence. Furthermore, some fundamental review of the LBM was also included in this report. Secondly, a description of the LBM and FEM coupling program, which has been developed so far, was described here along with some demonstration examples. The preliminary study showed a great potential of the proposed technique for FSI application. A sample computer program list is also attached as Appendix A. As a future benchmark study, a set of test cases were proposed so that experimental data would be obtained in the next phase of the study. These data would be beneficial to understand the fundamental physics of the FSI nature under different basic conditions, and also provide benchmark results against which the developed program at a later stage could be validated. Finally, the future research direction as the extension of the present work is provided with emphasis on its goal, as well as merits and benefits resulting from the proposed research for the regulatory evaluation activities of KINS and the associated technical activities of industries such as design, manufacturing, fabrication, operation and maintenance

  16. Polar bears at risk

    Energy Technology Data Exchange (ETDEWEB)

    Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

    2002-05-01

    Polar bears, the world's largest terrestrial carnivore, spend much of their lives on the arctic sea ice. This is where they hunt and move between feeding, denning, and resting areas. The world population, estimated at 22,000 bears, is made up of 20 relatively distinct populations varying in size from a few hundred to a few thousand animals. About 60 per cent of all polar bears are found in Canada. In general, the status of this species is stable, although there are pronounced differences between populations. Reductions in the extent and thickness of sea ice has lead the IUCN Polar Bear Specialist Group to describe climate change as one of the major threats facing polar bears today. Though the long-term effects of climate change will vary in different areas of the Arctic, impacts on the condition and reproductive success of polar bears and their prey are likely to be negative. Longer ice-free periods resulting from earlier break-up of sea ice in the spring and later formation in the fall is already impacting polar bears in the southern portions of their range. In Canada's Hudson Bay, for example, bears hunt on the ice through the winter and into early summer, after which the ice melts completely, forcing bears ashore to fast on stored fat until freeze-up in the fall. The time bears have on the ice to hunt and build up their body condition is cut short when the ice melts early. Studies from Hudson Bay show that for every week earlier that ice break-up occurs, bears will come ashore 10 kg lighter and in poorer condition. It is likely that populations of polar bears dividing their time between land and sea will be severely reduced and local extinctions may occur as greenhouse gas emissions continue to rise and sea ice melts. Expected changes in regional weather patterns will also impact polar bears. Rain in the late winter can cause maternity dens to collapse before females and cubs have departed, thus exposing occupants to the elements and to predators. Such

  17. MIMO channel capacity versus mutual coupling in multi antenna element system

    DEFF Research Database (Denmark)

    Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2004-01-01

    In this paper the influence of mutual coupling on the capacity of a multiple-input multiple-output (MIMO) antenna system is demonstrated. No direct relation between the envelope correlation and the actual location and orientation of the antennas is found. Even though being essential for high MIMO...... capacity, configurations with the lowest envelope correlations are not necessarily the most suitable for a MIMO system. A certain bandwidth is required as well. Three planar inverted F-antennas (PIFA) located on the same 40 mm x 100 mm ground plane. The antennas that haves a resonant frequency of 1.8 GHz...

  18. A multiscale coupled finite-element and phase-field framework to modeling stressed grain growth in polycrystalline thin films

    Energy Technology Data Exchange (ETDEWEB)

    Jamshidian, M., E-mail: jamshidian@cc.iut.ac.ir [Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Institute of Structural Mechanics, Bauhaus-University Weimar, Marienstrasse 15, 99423 Weimar (Germany); Thamburaja, P., E-mail: prakash.thamburaja@gmail.com [Department of Mechanical & Materials Engineering, Universiti Kebangsaan Malaysia (UKM), Bangi 43600 (Malaysia); Rabczuk, T., E-mail: timon.rabczuk@tdt.edu.vn [Division of Computational Mechanics, Ton Duc Thang University, Ho Chi Minh City (Viet Nam); Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City (Viet Nam)

    2016-12-15

    A previously-developed finite-deformation- and crystal-elasticity-based constitutive theory for stressed grain growth in cubic polycrystalline bodies has been augmented to include a description of excess surface energy and grain-growth stagnation mechanisms through the use of surface effect state variables in a thermodynamically-consistent manner. The constitutive theory was also implemented into a multiscale coupled finite-element and phase-field computational framework. With the material parameters in the constitutive theory suitably calibrated, our three-dimensional numerical simulations show that the constitutive model is able to accurately predict the experimentally-determined evolution of crystallographic texture and grain size statistics in polycrystalline copper thin films deposited on polyimide substrate and annealed at high-homologous temperatures. In particular, our numerical analyses show that the broad texture transition observed in the annealing experiments of polycrystalline thin films is caused by grain growth stagnation mechanisms. - Graphical abstract: - Highlights: • Developing a theory for stressed grain growth in polycrystalline thin films. • Implementation into a multiscale coupled finite-element and phase-field framework. • Quantitative reproduction of the experimental grain growth data by simulations. • Revealing the cause of texture transition to be due to the stagnation mechanisms.

  19. Elemental labelling combined with liquid chromatography inductively coupled plasma mass spectrometry for quantification of biomolecules: A review

    Science.gov (United States)

    Kretschy, Daniela; Koellensperger, Gunda; Hann, Stephan

    2012-01-01

    This article reviews novel quantification concepts where elemental labelling is combined with flow injection inductively coupled plasma mass spectrometry (FI-ICP-MS) or liquid chromatography inductively coupled plasma mass spectrometry (LC–ICP-MS), and employed for quantification of biomolecules such as proteins, peptides and related molecules in challenging sample matrices. In the first sections an overview on general aspects of biomolecule quantification, as well as of labelling will be presented emphasizing the potential, which lies in such methodological approaches. In this context, ICP-MS as detector provides high sensitivity, selectivity and robustness in biological samples and offers the capability for multiplexing and isotope dilution mass spectrometry (IDMS). Fundamental methodology of elemental labelling will be highlighted and analytical, as well as biomedical applications will be presented. A special focus will lie on established applications underlining benefits and bottlenecks of such approaches for the implementation in real life analysis. Key research made in this field will be summarized and a perspective for future developments including sophisticated and innovative applications will given. PMID:23062431

  20. Trace element determination using static high-sensitivity inductively coupled plasma optical emission spectrometry (SHIP-OES).

    Science.gov (United States)

    Engelhard, Carsten; Scheffer, Andy; Nowak, Sascha; Vielhaber, Torsten; Buscher, Wolfgang

    2007-02-05

    A low-flow air-cooled inductively coupled plasma (ICP) design for optical emission spectrometry (OES) with axial plasma viewing is described and an evaluation of its analytical capabilities in trace element determinations is presented. Main advantage is a total argon consumption of 0.6 L min(-1) in contrast to 15 L min(-1) using conventional ICP sources. The torch was evaluated in trace element determinations and studied in direct comparison with a conventional torch under the same conditions with the same OES system, ultrasonic nebulization (USN) and single-element optimization. A variety of parameters (x-y-position of the torch, rf power, external air cooling, gas flow rates and USN operation parameters) was optimized to achieve limits of detection (LOD) which are competitive to those of a conventional plasma source. Ionic to atomic line intensity ratios for magnesium were studied at different radio frequency (rf) power conditions and different sample carrier gas flows to characterize the robustness of the excitation source. A linear dynamic range of three to five orders of magnitude was determined under compromise conditions in multi-element mode. The accuracy of the system was investigated by the determination of Co, Cr, Mn, Zn in two certified reference materials (CRM): CRM 075c (Copper with added impurities), and CRM 281 (Trace elements in rye grass). With standard addition values of 2.44+/-0.04 and 3.19+/-0.21 microg g(-1) for Co and Mn in the CRM 075c and 2.32+/-0.09, 81.8+/-0.4, 32.2+/-3.9 for Cr, Mn and Zn, respectively, were determined in the samples and found to be in good agreement with the reported values; recovery rates in the 98-108% range were obtained. No influence on the analysis by the matrix load in the sample was observed.

  1. Food authenticity studies via multi-elemental and isotopic pattern using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Katona, R.; Brunner, M.; Abranko, L.; Prohaska, T.; Stefanka, Z.

    2009-01-01

    Full text: The aim of our study has been the development of an analytical method based on Sr isotope and elemental fingerprint analysis for discriminating food samples from different geographical origin. Several types of foods were involved in the investigation representing different stages of food processing such as pulverized spicy paprika (sparsely processed food product) and wine samples (processed product). Independent inorganic mass spectrometric techniques like ICP-SFMS, ICP-CCMS, and MC-ICPMS were used for method validation and investigation of the geographical origin. The advantage and limitations of the developed methods are discussed critically. (author)

  2. Simulation and control element design for a coupled aerodynamic/magnetic system

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, E

    1982-11-01

    Aerodynamic effects are among the many problems raised by the Maglev technique and its industrial application, but until recently they were only regarded as disturbances. Theoretical studies as well as model experiments in wind and water tunnels were only interested in optimizing the shape of the vehicle cell. The most important goals of development were low sensitivity to side-wind and a neutral aerodynamic design of the vehicle nose. The present paper investigates the aerodynamic effects by means of extended models. Aerodynamic effects on the elevation control system are considered by a suitable control element structure.

  3. Elemental fractionation in 785 nm picosecond and femtosecond laser ablation inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Shaheen, M.E., E-mail: mshaheen73@science.tanta.edu.eg [Department of Physics, Faculty of Sciences, Tanta University, Tanta (Egypt); Gagnon, J.E.; Fryer, B.J. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

    2015-05-01

    Elemental fractionation and ICP-MS signal response were investigated for two different pulse width laser beams originating from the same laser system. Femtosecond and picosecond laser beams at pulse widths of 130 fs and 110 ps, respectively, and wavelength of 785 nm were used to ablate NIST 610 synthetic glass and SRM 1107 Naval Brass B at the same spot for 800 to 1000 laser pulses at different repetition rates (5 to 50 Hz). Elemental fractionation was found to depend on repetition rate and showed a trend with femtosecond laser ablation that is opposite to that observed in picosecond laser ablation for most measured isotopes. ICP-MS signal intensity was higher in femtosecond than picosecond LA-ICP-MS in both NIST 610 and naval brass when ablation was conducted under the same fluence and repetition rate. The differences in signal intensity were partly related to differences in particle size distribution between particles generated by femtosecond and picosecond laser pulses and the consequent differences in transport and ionization efficiencies. The main reason for the higher signal intensity resulting from femtosecond laser pulses was related to the larger crater sizes compared to those created during picosecond laser ablation. Elemental ratios measured using {sup 66}Zn/{sup 63}Cu, {sup 208}Pb/{sup 238}U, {sup 232}Th/{sup 238}U, {sup 66}Zn/{sup 232}Th and {sup 66}Zn/{sup 208}Pb were found to change with the number of laser pulses with data points being more scattered in picosecond than femtosecond laser pulses. Reproducibility of replicate measurements of signal intensities, fractionation and elemental ratios was better for fs-LA-ICP-MS (RSD ~ 3 to 6%) than ps-LA-ICP-MS (RSD ~ 7 to 11%). - Highlights: • Fractionation and ICP-MS signal response were investigated for two different pulse widths using NIST 610 and Naval Brass. • Dependence of fractionation indices on repetition rate and pulse width. • Higher ablation rate was observed in picosecond compared to

  4. Elemental fractionation in 785 nm picosecond and femtosecond laser ablation inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Shaheen, M.E.; Gagnon, J.E.; Fryer, B.J.

    2015-01-01

    Elemental fractionation and ICP-MS signal response were investigated for two different pulse width laser beams originating from the same laser system. Femtosecond and picosecond laser beams at pulse widths of 130 fs and 110 ps, respectively, and wavelength of 785 nm were used to ablate NIST 610 synthetic glass and SRM 1107 Naval Brass B at the same spot for 800 to 1000 laser pulses at different repetition rates (5 to 50 Hz). Elemental fractionation was found to depend on repetition rate and showed a trend with femtosecond laser ablation that is opposite to that observed in picosecond laser ablation for most measured isotopes. ICP-MS signal intensity was higher in femtosecond than picosecond LA-ICP-MS in both NIST 610 and naval brass when ablation was conducted under the same fluence and repetition rate. The differences in signal intensity were partly related to differences in particle size distribution between particles generated by femtosecond and picosecond laser pulses and the consequent differences in transport and ionization efficiencies. The main reason for the higher signal intensity resulting from femtosecond laser pulses was related to the larger crater sizes compared to those created during picosecond laser ablation. Elemental ratios measured using 66 Zn/ 63 Cu, 208 Pb/ 238 U, 232 Th/ 238 U, 66 Zn/ 232 Th and 66 Zn/ 208 Pb were found to change with the number of laser pulses with data points being more scattered in picosecond than femtosecond laser pulses. Reproducibility of replicate measurements of signal intensities, fractionation and elemental ratios was better for fs-LA-ICP-MS (RSD ~ 3 to 6%) than ps-LA-ICP-MS (RSD ~ 7 to 11%). - Highlights: • Fractionation and ICP-MS signal response were investigated for two different pulse widths using NIST 610 and Naval Brass. • Dependence of fractionation indices on repetition rate and pulse width. • Higher ablation rate was observed in picosecond compared to femtosecond laser ablation of NIST 610 and Brass

  5. Simulated evolution of fractures and fracture networks subject to thermal cooling: A coupled discrete element and heat conduction model

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hai; Plummer, Mitchell; Podgorney, Robert

    2013-02-01

    Advancement of EGS requires improved prediction of fracture development and growth during reservoir stimulation and long-term operation. This, in turn, requires better understanding of the dynamics of the strongly coupled thermo-hydro-mechanical (THM) processes within fractured rocks. We have developed a physically based rock deformation and fracture propagation simulator by using a quasi-static discrete element model (DEM) to model mechanical rock deformation and fracture propagation induced by thermal stress and fluid pressure changes. We also developed a network model to simulate fluid flow and heat transport in both fractures and porous rock. In this paper, we describe results of simulations in which the DEM model and network flow & heat transport model are coupled together to provide realistic simulation of the changes of apertures and permeability of fractures and fracture networks induced by thermal cooling and fluid pressure changes within fractures. Various processes, such as Stokes flow in low velocity pores, convection-dominated heat transport in fractures, heat exchange between fluid-filled fractures and solid rock, heat conduction through low-permeability matrices and associated mechanical deformations are all incorporated into the coupled model. The effects of confining stresses, developing thermal stress and injection pressure on the permeability evolution of fracture and fracture networks are systematically investigated. Results are summarized in terms of implications for the development and evolution of fracture distribution during hydrofracturing and thermal stimulation for EGS.

  6. Simultaneous determination of macronutrients, micronutrients and trace elements in mineral fertilizers by inductively coupled plasma optical emission spectrometry

    International Nuclear Information System (INIS)

    Oliveira Souza, Sidnei de; Silvério Lopes da Costa, Silvânio; Santos, Dayane Melo; Santos Pinto, Jéssica dos; Garcia, Carlos Alexandre Borges

    2014-01-01

    An analytical method for simultaneous determination of macronutrients (Ca, Mg, Na and P), micronutrients (Cu, Fe, Mn and Zn) and trace elements (Al, As, Cd, Pb and V) in mineral fertilizers was optimized. Two-level full factorial design was applied to evaluate the optimal proportions of reagents used in the sample digestion on hot plate. A Doehlert design for two variables was used to evaluate the operating conditions of the inductively coupled plasma optical emission spectrometer in order to accomplish the simultaneous determination of the analyte concentrations. The limits of quantification (LOQs) ranged from 2.0 mg kg −1 for Mn to 77.3 mg kg −1 for P. The accuracy and precision of the proposed method were evaluated by analysis of standard reference materials (SRMs) of Western phosphate rock (NIST 694), Florida phosphate rock (NIST 120C) and Trace elements in multi-nutrient fertilizer (NIST 695), considered to be adequate for simultaneous determination. Twenty-one samples of mineral fertilizers collected in Sergipe State, Brazil, were analyzed. For all samples, the As, Ca, Cd and Pb concentrations were below the LOQ values of the analytical method. For As, Cd and Pb the obtained LOQ values were below the maximum limit allowed by the Brazilian Ministry of Agriculture, Livestock and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento — MAPA). The optimized method presented good accuracy and was effectively applied to quantitative simultaneous determination of the analytes in mineral fertilizers by inductively coupled plasma optical emission spectrometry (ICP OES). - Highlights: • Determination of inorganic constituents in mineral fertilizers was proposed. • Experimental design methodology was used to optimize analytical method. • The sample preparation procedure using diluted reagents (HNO 3 and H 2 O 2 ) was employed. • The analytical method was satisfactorily to the determination of thirteen elements. • The ICP OES technique can be

  7. Determination of rare earth elements in seawater by inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Moeller, P.; Dulski, P.; Luck, J.

    1992-01-01

    Shortly after sampling, rare earth elements (REEs) from 11.5 l of seawater were concentrated in 35 ml solutions by ion exchange chromatography on board the German research vessel ''Sonne'' using Chelex 100 chelating resin for preconcentration. Two millilitres of a 0.2 μg g -1 Lu spike was added to the seawater samples (i) for monitoring the chemical yield which was always found to vary between 85 and 112% (mean: 100±6) and (ii) as an internal standard. Rare earth elements have been determined by ICP-MS, with REE concentrations ranging from 100 (La) to 1 (Eu) pmol kg -1 . La in blanks can be as high as 30 pmol kg -1 , but blank concentrations for other REEs range between 0.5 and 0.01 pmol kg -1 . The trend of the precision of relative response factors varies between 12% (La) and 4% (Yb). The accuracy is estimated to be about 10% with the exception of La and Ce. Methodology improvements are suggested. (author)

  8. Conjugation of fiber-coupled wide-band light sources and acousto-optical spectral elements

    Science.gov (United States)

    Machikhin, Alexander; Batshev, Vladislav; Polschikova, Olga; Khokhlov, Demid; Pozhar, Vitold; Gorevoy, Alexey

    2017-12-01

    Endoscopic instrumentation is widely used for diagnostics and surgery. The imaging systems, which provide the hyperspectral information of the tissues accessible by endoscopes, are particularly interesting and promising for in vivo photoluminescence diagnostics and therapy of tumour and inflammatory diseases. To add the spectral imaging feature to standard video endoscopes, we propose to implement acousto-optical (AO) filtration of wide-band illumination of incandescent-lamp-based light sources. To collect maximum light and direct it to the fiber-optic light guide inside the endoscopic probe, we have developed and tested the optical system for coupling the light source, the acousto-optical tunable filter (AOTF) and the light guide. The system is compact and compatible with the standard endoscopic components.

  9. FLOW INJECTION ANALYSIS SYSTEM COUPLED WITH ICP-EOS FOR DETERMINATION OF SOME METALLIC ELEMENTS IN DRINKING WATER

    Directory of Open Access Journals (Sweden)

    Cristina Dinu

    2009-06-01

    Full Text Available The European Drinking Water Directive (98/83/EC, transposed in Romanian Legislation as Low 458/2002, amended by Low 311/2004, imposes the limit of concentration for metallic elements in water intended for human consumption. The toxic metals arsenic and selenium are among these elements and the limit value is 10 μg/L. In the paper there are presented the working conditions for determination of As and Se from drinking water using modern techniques based on the fl ow injection-hydride generation with the inductively coupled plasma atomic emission spectrometry (FIAS-ICP-EOS. The analyses were performed on Optima 5300 DV Perkin Elmer equipment with FIAS 400 Flow Injection System, Perkin Elmer type. For the hydride generation two types of solution were used: 10% (v/v HCl as a carrier solution and 0.2 % NaBH4 in 0.05%NaOH solution as a reducing agent [1]. The treatment step of the samples and standard solutions consisted in reducing with mixed solutions of KI and ascorbic acid in acidic condition (HCl for As and only with HCl and high temperature for Se [2,3]. The paper contains the characteristic parameters of the methods, such as: low detection limit, quantifi cation limit, repeatability, precision, recovery, which were evaluated using Certifi ed Reference Materials for each element.

  10. A provenance study of iron archaeological artefacts by Inductively Coupled Plasma-Mass Spectrometry multi-elemental analysis

    International Nuclear Information System (INIS)

    Desaulty, Anne-Marie; Mariet, Clarisse; Dillmann, Philippe; Joron, Jean Louis; Fluzin, Philippe

    2008-01-01

    Raw materials and wastes (i.e. ore, slag and laitier) from ironmaking archaeological sites have been analyzed in order to understand the behavior of the trace elements in the ancient ironmaking processes and to find the significant-most elements to characterize an iron making region. The ICP-MS (Inductively Coupled Plasma Mass Spectrometry) appears to be an excellent technique for this type of studies. The comparison between the ICP-MS results obtained with the Standard Addition method and the INAA (Instrumental Neutron Activation Analyses) results proved that Sc, Co, (Ni), Rb, Cs, Ba, La, Ce, Sm, Eu, Yb, Hf, Th, U contents in the ores, slag and laitiers, and Co and Ni contents in the cast iron can be successfully determined by ICP-MS after wet acid digestion (low detection limits, good sensitivity and precision). By using significant trace element pairs (Yb/Ce, Ce/Th, La/Sc, U/Th, Nb/Y) present in the ores, laitiers and slag, it is possible to discriminate different French ironmaking regions as the Pays de Bray, Lorraine and Pays d'Ouche. These results open the way to further studies on the provenance of iron objects. The comparison between the ICP-MS results obtained with the Standard Calibration Curves method and the INAA results shows that matrices rich in iron, affect the ICP-MS analyses by suppressing the analytes signal. Further studies are necessary to improve understanding matrix effects

  11. A fully-coupled discontinuous Galerkin spectral element method for two-phase flow in petroleum reservoirs

    Science.gov (United States)

    Taneja, Ankur; Higdon, Jonathan

    2018-01-01

    A high-order spectral element discontinuous Galerkin method is presented for simulating immiscible two-phase flow in petroleum reservoirs. The governing equations involve a coupled system of strongly nonlinear partial differential equations for the pressure and fluid saturation in the reservoir. A fully implicit method is used with a high-order accurate time integration using an implicit Rosenbrock method. Numerical tests give the first demonstration of high order hp spatial convergence results for multiphase flow in petroleum reservoirs with industry standard relative permeability models. High order convergence is shown formally for spectral elements with up to 8th order polynomials for both homogeneous and heterogeneous permeability fields. Numerical results are presented for multiphase fluid flow in heterogeneous reservoirs with complex geometric or geologic features using up to 11th order polynomials. Robust, stable simulations are presented for heterogeneous geologic features, including globally heterogeneous permeability fields, anisotropic permeability tensors, broad regions of low-permeability, high-permeability channels, thin shale barriers and thin high-permeability fractures. A major result of this paper is the demonstration that the resolution of the high order spectral element method may be exploited to achieve accurate results utilizing a simple cartesian mesh for non-conforming geological features. Eliminating the need to mesh to the boundaries of geological features greatly simplifies the workflow for petroleum engineers testing multiple scenarios in the face of uncertainty in the subsurface geology.

  12. Towards an integrated numerical simulator for crack-seal vein microstructure: Coupling phase-field with the Discrete Element Method

    Science.gov (United States)

    Virgo, Simon; Ankit, Kumar; Nestler, Britta; Urai, Janos L.

    2016-04-01

    Crack-seal veins form in a complex interplay of coupled thermal, hydraulic, mechanical and chemical processes. Their formation and cyclic growth involves brittle fracturing and dilatancy, phases of increased fluid flow and the growth of crystals that fill the voids and reestablish the mechanical strength. Existing numerical models of vein formation focus on selected aspects of the coupled process. Until today, no model exists that is able to use a realistic representation of the fracturing AND sealing processes, simultaneously. To address this challenge, we propose the bidirectional coupling of two numerical methods that have proven themselves as very powerful to model the fundamental processes acting in crack-seal systems: Phase-field and the Discrete Element Method (DEM). The phase-field Method was recently successfully extended to model the precipitation of quartz crystals from an aqueous solution and applied to model the sealing of a vein over multiple opening events (Ankit et al., 2013; Ankit et al., 2015a; Ankit et al., 2015b). The advantage over former, purely kinematic approaches is that in phase-field, the crystal growth is modeled based on thermodynamic and kinetic principles. Different driving forces for microstructure evolution, such as chemical bulk free energy, interfacial energy, elastic strain energy and different transport processes, such as mass diffusion and advection, can be coupled and the effect on the evolution process can be studied in 3D. The Discrete Element Method was already used in several studies to model the fracturing of rocks and the incremental growth of veins by repeated fracturing (Virgo et al., 2013; Virgo et al., 2014). Materials in DEM are represented by volumes of packed spherical particles and the response to the material to stress is modeled by interaction of the particles with their nearest neighbours. For rocks, in 3D, the method provides a realistic brittle failure behaviour. Exchange Routines are being developed that

  13. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  14. Grizzly bear

    Science.gov (United States)

    Schwartz, C.C.; Miller, S.D.; Haroldson, M.A.; Feldhamer, G.; Thompson, B.; Chapman, J.

    2003-01-01

    The grizzly bear inspires fear, awe, and respect in humans to a degree unmatched by any other North American wild mammal. Like other bear species, it can inflict serious injury and death on humans and sometimes does. Unlike the polar bear (Ursus maritimus) of the sparsely inhabited northern arctic, however, grizzly bears still live in areas visited by crowds of people, where presence of the grizzly remains physically real and emotionally dominant. A hike in the wilderness that includes grizzly bears is different from a stroll in a forest from which grizzly bears have been purged; nighttime conversations around the campfire and dreams in the tent reflect the presence of the great bear. Contributing to the aura of the grizzly bear is the mixture of myth and reality about its ferocity. unpredictable disposition, large size, strength, huge canines, long claws, keen senses, swiftness, and playfulness. They share characteristics with humans such as generalist life history strategies. extended periods of maternal care, and omnivorous diets. These factors capture the human imagination in ways distinct from other North American mammals. Precontact Native American legends reflected the same fascination with the grizzly bear as modern stories and legends (Rockwell 1991).

  15. An Assessment of Gas Foil Bearing Scalability and the Potential Benefits to Civilian Turbofan Engines

    Science.gov (United States)

    Bruckner, Robert J.

    2010-01-01

    Over the past several years the term oil-free turbomachinery has been used to describe a rotor support system for high speed turbomachinery that does not require oil for lubrication, damping, or cooling. The foundation technology for oil-free turbomachinery is the compliant foil bearing. This technology can replace the conventional rolling element bearings found in current engines. Two major benefits are realized with this technology. The primary benefit is the elimination of the oil lubrication system, accessory gearbox, tower shaft, and one turbine frame. These components account for 8 to 13 percent of the turbofan engine weight. The second benefit that compliant foil bearings offer to turbofan engines is the capability to operate at higher rotational speeds and shaft diameters. While traditional rolling element bearings have diminished life, reliability, and load capacity with increasing speeds, the foil bearing has a load capacity proportional to speed. The traditional applications for foil bearings have been in small, lightweight machines. However, recent advancements in the design and manufacturing of foil bearings have increased their potential size. An analysis, grounded in experimentally proven operation, is performed to assess the scalability of the modern foil bearing. This analysis was coupled to the requirements of civilian turbofan engines. The application of the foil bearing to larger, high bypass ratio engines nominally at the 120 kN (approx.25000 lb) thrust class has been examined. The application of this advanced technology to this system was found to reduce mission fuel burn by 3.05 percent.

  16. Roller bearing geometry design

    Science.gov (United States)

    Savage, M.; Pinkston, B. H. W.

    1976-01-01

    A theory of kinematic stabilization of rolling cylinders is extended and applied to the design of cylindrical roller bearings. The kinematic stabilization mechanism puts a reverse skew into the rolling elements by changing the roller taper. Twelve basic bearing modification designs are identified amd modeled. Four have single transverse convex curvature in their rollers while eight have rollers which have compound transverse curvature made up of a central cylindrical band surrounded by symmetric bands with slope and transverse curvature. The bearing designs are modeled for restoring torque per unit axial displacement, contact stress capacity, and contact area including dynamic loading, misalignment sensitivity and roller proportion. Design programs are available which size the single transverse curvature roller designs for a series of roller slopes and load separations and which design the compound roller bearings for a series of slopes and transverse radii of curvature. The compound rollers are proportioned to have equal contact stresses and minimum size. Design examples are also given.

  17. Application of inductively coupled plasma mass spectrometry (ICP/MS) to detection of trace elements, heavy metals and radioisotopes in scalp hair

    International Nuclear Information System (INIS)

    Ozturk, Yildirim; Benderli, Cihan

    2010-01-01

    Trace element analysis of human hair has the potential to reveal retrospective information about an individual's nutritional status and exposure. As trace elements are incorporated into the hair during the growth process, longitudinal segments of the hair may reflect the body burden during the growth period. it was evaluated the potential of human hair to indicate exposure or nutritional status over time by analysing trace element profiles in single strands of human hair. By using inductively coupled plasma mass spectrometry (ICP-MS), it was achieved profiles of 43 elements in single strands of human hair. It was shown that trace element analysis along single strands of human hair can yield information about essential and toxic elements and for some elements, can be correlated with seasonal changes in diet and exposure. The information obtained from the trace element profiles of human hair in this study substantiates the potential of hair as a biomarker

  18. Application of a particle separation device to reduce inductively coupled plasma-enhanced elemental fractionation in laser ablation-inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Guillong, Marcel; Kuhn, Hans-Rudolf; Guenther, Detlef

    2003-01-01

    The particle size distribution of laser ablation aerosols are a function of the wavelength, the energy density and the pulse duration of the laser, as well as the sample matrix and the gas environment. Further the size of the particles affects the vaporization and ionization efficiency in the inductively coupled plasma (ICP). Some matrices produce large particles, which are not completely vaporized and ionized in the ICP. The previous work has shown that analytical results such as matrix-independent calibration, accuracy and precision can be significantly influenced by the particle sizes of the particles. To minimize the particle size related incomplete conversion of the sample to ions in the ICP a particle separation device was developed, which allows effective particle separation using centrifugal forces in a thin coiled tube. In this device, the particle cut-off size is varied by changing the number of turns in the coil, as well as by changing the gas flow and the tube diameter. The interaction of the laser with the different samples leads to varying particle size distributions. When carrying out quantitative analysis with non-matrix matched calibration reference materials, it was shown that different particle cut-off sizes were required depending on the ICP conditions and the instrument used for analysis. Various sample materials were investigated in this study to demonstrate the applicability of the device. For silicate matrices, the capability of the ICP to produce ions was significantly reduced for particles larger than 0.5 μm, and was dependent on the element monitored. To reduce memory effects caused by the separated particles, a washout procedure was developed, which additionally allowed the analysis of the trapped particles. These results clearly demonstrate the very important particle size dependent ICP-MS signal response and the potential of the described particle size based separator for the reduction of ICP induced elemental fractionation

  19. Use of magnesium as a test element for inductively coupled plasma atomic emission spectrometry diagnosis

    International Nuclear Information System (INIS)

    Mermet, J.M.

    1991-01-01

    To optimize atomization and ionization processes in an inductively coupled plasma used as a source in atomic emission spectrometry, the Mg II 280.270-nm/Mg I 285-213-nm line intensity ratio is used. A theoretic ratio is calculated assuming a local thermodynamic equilibrium.A review of previously published experimental values of the ratio is given as a function of the parameters influencing the energy transfer between the plasma and injected species. In particular, the effects of the power, the carrier gas flow-rate, the i.d. of the torch injector, the use of a sheathing gas and the presence of hydrogen are described. Values of the ratio close to the theoretical values are obtained with a high power (>1.4 kW), a lower carrier gas flow-rate ( -1 ) and a large i.d. of the injector (>2 mm). This optimization can also be applied to the minimization of interference effects due to the presence of sodium. (author). 64 refs.; 9 figs.; 1 tab

  20. Model of the saltation transport by Discrete Element Method coupled with wind interaction

    Directory of Open Access Journals (Sweden)

    Oger Luc

    2017-01-01

    Full Text Available We study the Aeolian saltation transport problem by analysing the collision of incident energetic beads with granular packing. We investigate the collision process for the case where the incident bead and those from the packing have identical mechanical properties. We analyse the features of the consecutive collision process. We used a molecular dynamics method known as DEM (soft Discrete Element Method with 20000 particles (2D. The grains were displayed randomly in a box (250X60. A few incident disks are launched with a constant velocity and angle with high random position to initiate the flow. A wind velocity profile is applied on the flowing zone of the saltation. The velocity profile is obtained by the calculi of the counter-flow due to the local packing fraction induced by the granular flow. We analyse the evolution of the upper surface of the disk packing. In the beginning, the saltation process can be seen as the classical “splash function” in which one bead hits a fully static dense packing. Then, the quasi-fluidized upper layer of the packing creates a completely different behaviour of the “animated splash function”. The dilation of the upper surface due to the previous collisions is responsible for a need of less input energy for launching new ejected disks. This phenomenon permits to maintain a constant granular flow with a “small” wind velocity on the surface of the disk bed.

  1. Laser ablation inductively coupled plasma dynamic reaction cell mass spectrometry for the multi-element analysis of polymers

    Science.gov (United States)

    Resano, M.; García-Ruiz, E.; Vanhaecke, F.

    2005-11-01

    In this work, the potential of laser ablation-inductively coupled plasma-mass spectrometry for the fast analysis of polymers has been explored. Different real-life samples (polyethylene shopping bags, an acrylonitrile butadiene styrene material and various plastic bricks) as well as several reference materials (VDA 001 to 004, Cd in polyethylene) have been selected for the study. Two polyethylene reference materials (ERM-EC 680 and 681), for which a reference or indicative value for the most relevant metals is available, have proved their suitability as standards for calibration. Special attention has been paid to the difficulties expected for the determination of Cr at the μg g - 1 level in this kind of materials, due to the interference of ArC + ions on the most abundant isotopes of Cr. The use of ammonia as a reaction gas in a dynamic reaction cell is shown to alleviate this problem, resulting in a limit of detection of 0.15 μg g - 1 for this element, while limiting only modestly the possibilities of the technique for simultaneous multi-element analysis. In this regard, As is the analyte most seriously affected by the use of ammonia, and its determination has to be carried out in vented mode, at the expense of measuring time. In all cases studied, accurate results could be obtained for elements ranging in content from the sub-μg g - 1 level to tens of thousands of μg g - 1 . However, the use of an element of known concentration as internal standard may be needed for materials with a matrix significantly different from that of the standard (polyethylene in this work). Precision ranged between 5% and 10% RSD for elements found at the 10 μg g - 1 level or higher, while this value could deteriorate to 20% for analytes found at the sub-μg g - 1 level. Overall, the technique evaluated presents many advantages for the fast and accurate multi-element analysis of these materials, avoiding laborious digestion procedures and minimizing the risk of analyte losses due

  2. Mobility of major and trace elements in a coupled groundwater-surface water system: Merced River, CA

    Science.gov (United States)

    Wildman, R. A.; Domagalski, J. L.; Hering, J. G.

    2004-12-01

    Trace element transport in coupled surface water/groundwater systems is controlled not only by advective flow, but also by redox reactions that affect the partitioning of various elements between mobile and immobile phases. These processes have been examined in the context of a field project conducted by the U.S. Geological Survey (USGS) as part of the National Water-Quality Assessment (NAWQA) program. The Merced River flows out of Yosemite National Park and the Sierra Nevada foothills and into California's Central Valley, where it joins the San Joaquin River. Our field site is approximately twenty river kilometers from the confluence with the San Joaquin River. This deep alluvial plain has minimal topography. Agricultural development characterizes the land surrounding this reach of river; consequently, the hydrology is heavily influenced by irrigation. Riverbed groundwater samples were collected from ten wells aligned in two transects across the river located approximately 100 m apart. The wells were sampled from depths of 0.5 m, 1 m, and 3 m below the sediment-water interface. Groundwater flowpath samples were taken from wells positioned on a path perpendicular to the river and located 100 m, 500 m, and 1000 m from the river. The saturated groundwater system exists from 7 to 40 m below the surface and is confined below by a clay layer. Each well location samples from 3-5 depths in this surface aquifer. Samples were collected in December 2003, March-April, June-July, and October 2004. This served to provide an evenly-spaced sampling frequency over the course of a year, and also to allow observation of trends coinciding with the onset of winter, the spring runoff, and early and late summer irrigation. An initial survey of the elements in the riverbed samples was conducted using Inductively-Coupled Plasma Mass Spectrometry (ICP-MS). Elements for further study were selected based on variability in this survey, either with respect to depth or location, as well as to

  3. Bacterial Disproportionation of Elemental Sulfur Coupled to Chemical Reduction of Iron or Manganese

    Science.gov (United States)

    Thamdrup, Bo; Finster, Kai; Hansen, Jens Würgler; Bak, Friedhelm

    1993-01-01

    A new chemolithotrophic bacterial metabolism was discovered in anaerobic marine enrichment cultures. Cultures in defined medium with elemental sulfur (S0) and amorphous ferric hydroxide (FeOOH) as sole substrates showed intense formation of sulfate. Furthermore, precipitation of ferrous sulfide and pyrite was observed. The transformations were accompanied by growth of slightly curved, rod-shaped bacteria. The quantification of the products revealed that S0 was microbially disproportionated to sulfate and sulfide, as follows: 4S0 + 4H2O → SO42- + 3H2S + 2H+. Subsequent chemical reactions between the formed sulfide and the added FeOOH led to the observed precipitation of iron sulfides. Sulfate and iron sulfides were also produced when FeOOH was replaced by FeCO3. Further enrichment with manganese oxide, MnO2, instead of FeOOH yielded stable cultures which formed sulfate during concomitant reduction of MnO2 to Mn2+. Growth of small rod-shaped bacteria was observed. When incubated without MnO2, the culture did not grow but produced small amounts of SO42- and H2S at a ratio of 1:3, indicating again a disproportionation of S0. The observed microbial disproportionation of S0 only proceeds significantly in the presence of sulfide-scavenging agents such as iron and manganese compounds. The population density of bacteria capable of S0 disproportionation in the presence of FeOOH or MnO2 was high, > 104 cm-3 in coastal sediments. The metabolism offers an explanation for recent observations of anaerobic sulfide oxidation to sulfate in anoxic sediments. PMID:16348835

  4. Elemental analysis of forensic glasses by inductively coupled plasma mass spectrometry

    Science.gov (United States)

    Almirall, Jose R.; Duckworth, Douglas C.; Bayne, Charles K.; Morton, Sherman A.; Smith, David H.; Koons, Robert D.; Furton, Kenneth G.

    1999-02-01

    Flat glass is a common type of evidence collected from the scenes of crimes such as burglaries, vandalism, and hit-and- run accidents. The usefulness of such evidence lies in the ability to associate the glass from the scene (or a suspect) to the original source. Physical and chemical analysis of the glass can be used for discrimination between the possible sources of glass. If the sample is large enough, physical attributes such as fracture matches, density, color, and thickness can be employed for comparison between a recovered fragment(s) to the suspect source. More commonly, refractive index (RI) comparisons are employed. Due to the improved control over glass manufacturing processes, RI values often cannot differentiate glasses where approximately 6 - 9% of casework samples are not expected to be distinguished by RI alone even if they originated from different sources. Employing methods such as NAA, XRF, ICP-AES, and ICP-MS for the comparison of trace elemental compositions has been shown to be more discriminating than RI comparisons. The multielement capability and the sensitivity of ICP-AES and ICP-MS provide for excellent discrimination power. In this work, the sources of variability in ICP-MS of glass analysis are investigated to determine possible sources of variation. The sources of variation examined include errors due to sample preparation, instrument accuracy and precision, and interlaboratory reproducibility. Other sources of variation include inhomogeneity across a sheet of glass from the same source. Analysis of variance has been applied to our ICP-MS analysis of NIST standards and to the interlaboratory comparisons of float glass samples collected across a sheet in a production facility. The results of these experiments allows for a more accurate interpretation of forensic glass data and a better understanding of the discriminating power (absolute and practical) of ICP-MS.

  5. Zircaloy-sheathed element rods fitted with thermo-couples; Barre combustible a thermocouple gainee de zircaloy

    Energy Technology Data Exchange (ETDEWEB)

    Bernardy de Sigoyer, B; Jacques, F; Thome, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    In order to carry out thermal conductivity measurements on UO{sub 2} in conditions similar to those under which fuel rods are used, it was necessary to measure the temperature at the interior of a fuel element sheathed in zircaloy. The temperatures are taken with Thermocoax type thermocouples, that is to say fitted with a very thin sheath of stainless steel or Inconel. It is known also that fusion welding of zircaloy onto stainless steel is impossible and that high temperature welded joints are very difficult because of their aggressiveness. The technique used consists in brazing the thermocouples to relatively large stainless steel parts and then joining these plugs by electron bombardment welding to diffused stainless steel-zircaloy couplings. The properties of these diffused couplings and of the brazed joints were studied; the various stages in the fabrication of the containers are also described. (authors) [French] Pour des mesures de conductivite thermique de l'UO{sub 2} dans des conditions voisines du fonctionnement des barres combustibles, il s'agissait de mesurer la temperature a l'interieur d'un element combustible gaine de zircaloy. Les prises de temperature sont faites par thermocouples du type Thermocoax, c'est-a-dire pourvu d'une gaine tres mince en inox ou inconel. Par ailleurs on sait que le soudage par fusion du zircaloy sur l'inox est impossible et que les brasures a haute temperature sont difficiles car tres agressives. La technique utilisee consiste a braser les thermocouples sur des pieces en inox relativement massives et de rapporter par soudage au bombardement electronique ces bouchons sur des raccords diffuses zircaloy-inox. Les proprietes de ces raccords diffuses et celles de joints brases ont ete etudiees; on expose egalement les diverses etapes de fabrication des containers. (auteurs)

  6. Simultaneous determination of macronutrients, micronutrients and trace elements in mineral fertilizers by inductively coupled plasma optical emission spectrometry

    Science.gov (United States)

    de Oliveira Souza, Sidnei; da Costa, Silvânio Silvério Lopes; Santos, Dayane Melo; dos Santos Pinto, Jéssica; Garcia, Carlos Alexandre Borges; Alves, José do Patrocínio Hora; Araujo, Rennan Geovanny Oliveira

    2014-06-01

    An analytical method for simultaneous determination of macronutrients (Ca, Mg, Na and P), micronutrients (Cu, Fe, Mn and Zn) and trace elements (Al, As, Cd, Pb and V) in mineral fertilizers was optimized. Two-level full factorial design was applied to evaluate the optimal proportions of reagents used in the sample digestion on hot plate. A Doehlert design for two variables was used to evaluate the operating conditions of the inductively coupled plasma optical emission spectrometer in order to accomplish the simultaneous determination of the analyte concentrations. The limits of quantification (LOQs) ranged from 2.0 mg kg- 1 for Mn to 77.3 mg kg- 1 for P. The accuracy and precision of the proposed method were evaluated by analysis of standard reference materials (SRMs) of Western phosphate rock (NIST 694), Florida phosphate rock (NIST 120C) and Trace elements in multi-nutrient fertilizer (NIST 695), considered to be adequate for simultaneous determination. Twenty-one samples of mineral fertilizers collected in Sergipe State, Brazil, were analyzed. For all samples, the As, Ca, Cd and Pb concentrations were below the LOQ values of the analytical method. For As, Cd and Pb the obtained LOQ values were below the maximum limit allowed by the Brazilian Ministry of Agriculture, Livestock and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento - MAPA). The optimized method presented good accuracy and was effectively applied to quantitative simultaneous determination of the analytes in mineral fertilizers by inductively coupled plasma optical emission spectrometry (ICP OES).

  7. Wave-induced stress and breaking of sea ice in a coupled hydrodynamic discrete-element wave-ice model

    Science.gov (United States)

    Herman, Agnieszka

    2017-11-01

    In this paper, a coupled sea ice-wave model is developed and used to analyze wave-induced stress and breaking in sea ice for a range of wave and ice conditions. The sea ice module is a discrete-element bonded-particle model, in which ice is represented as cuboid grains floating on the water surface that can be connected to their neighbors by elastic joints. The joints may break if instantaneous stresses acting on them exceed their strength. The wave module is based on an open-source version of the Non-Hydrostatic WAVE model (NHWAVE). The two modules are coupled with proper boundary conditions for pressure and velocity, exchanged at every wave model time step. In the present version, the model operates in two dimensions (one vertical and one horizontal) and is suitable for simulating compact ice in which heave and pitch motion dominates over surge. In a series of simulations with varying sea ice properties and incoming wavelength it is shown that wave-induced stress reaches maximum values at a certain distance from the ice edge. The value of maximum stress depends on both ice properties and characteristics of incoming waves, but, crucially for ice breaking, the location at which the maximum occurs does not change with the incoming wavelength. Consequently, both regular and random (Jonswap spectrum) waves break the ice into floes with almost identical sizes. The width of the zone of broken ice depends on ice strength and wave attenuation rates in the ice.

  8. Finite Element Modeling and Analysis of Nonlinear Impact and Frictional Motion Responses Including Fluid—Structure Coupling Effects

    Directory of Open Access Journals (Sweden)

    Yong Zhao

    1997-01-01

    Full Text Available A nonlinear three dimensional (3D single rack model and a nonlinear 3D whole pool multi-rack model are developed for the spent fuel storage racks of a nuclear power plant (NPP to determine impacts and frictional motion responses when subjected to 3D excitations from the supporting building floor. The submerged free standing rack system and surrounding water are coupled due to hydrodynamic fluid-structure interaction (FSI using potential theory. The models developed have features that allow consideration of geometric and material nonlinearities including (1 the impacts of fuel assemblies to rack cells, a rack to adjacent racks or pool walls, and rack support legs to the pool floor; (2 the hydrodynamic coupling of fuel assemblies with their storing racks, and of a rack with adjacent racks, pool walls, and the pool floor; and (3 the dynamic motion behavior of rocking, twisting, and frictional sliding of rack modules. Using these models 3D nonlinear time history dynamic analyses are performed per the U.S. Nuclear Regulatory Commission (USNRC criteria. Since few such modeling, analyses, and results using both the 3D single and whole pool multiple rack models are available in the literature, this paper emphasizes description of modeling and analysis techniques using the SOLVIA general purpose nonlinear finite element code. Typical response results with different Coulomb friction coefficients are presented and discussed.

  9. Circuit-field coupled finite element analysis method for an electromagnetic acoustic transducer under pulsed voltage excitation

    International Nuclear Information System (INIS)

    Hao Kuan-Sheng; Huang Song-Ling; Zhao Wei; Wang Shen

    2011-01-01

    This paper presents an analytical method for electromagnetic acoustic transducers (EMATs) under voltage excitation and considers the non-uniform distribution of the biased magnetic field. A complete model of EMATs including the non-uniform biased magnetic field, a pulsed eddy current field and the acoustic field is built up. The pulsed voltage excitation is transformed to the frequency domain by fast Fourier transformation (FFT). In terms of the time harmonic field equations of the EMAT system, the impedances of the coils under different frequencies are calculated according to the circuit-field coupling method and Poynting's theorem. Then the currents under different frequencies are calculated according to Ohm's law and the pulsed current excitation is obtained by inverse fast Fourier transformation (IFFT). Lastly, the sequentially coupled finite element method (FEM) is used to calculate the Lorentz force in the EMATs under the current excitation. An actual EMAT with a two-layer two-bundle printed circuit board (PCB) coil, a rectangular permanent magnet and an aluminium specimen is analysed. The coil impedances and the pulsed current are calculated and compared with the experimental results. Their agreement verified the validity of the proposed method. Furthermore, the influences of lift-off distances and the non-uniform static magnetic field on the Lorentz force under pulsed voltage excitation are studied. (interdisciplinary physics and related areas of science and technology)

  10. EFFECT OF BEARING MACROGEOMETRY ON BEARING PERFORMANCE IN ELASTOHYDRODYNAMIC LUBRICATION

    Directory of Open Access Journals (Sweden)

    Emin GÜLLÜ

    2000-01-01

    Full Text Available During manufacturing, ideal dimension and mutual positioning of machine elements proposed in project desing can be achieved only within certain range of tolerances. These tolerances, being classified in two groups, related to micro and macro geometry of machine elements, don't have to effect the functioning of these elements. So, as for all machine elements, investigation of the effects of macro and micro tolerances for journal bearings is important. In this study, we have investigated the effect of macro geometric irregularities of journal bearings on performance characteristics. In this regard, we have studied the change of bearing performance in respect to deviation from ideal circle for an elliptic shaft with small ovality rolling in circular journal bearing.

  11. Coupled large eddy simulation and discrete element model of bedload motion

    Science.gov (United States)

    Furbish, D.; Schmeeckle, M. W.

    2011-12-01

    We combine a three-dimensional large eddy simulation of turbulence to a three-dimensional discrete element model of turbulence. The large eddy simulation of the turbulent fluid is extended into the bed composed of non-moving particles by adding resistance terms to the Navier-Stokes equations in accordance with the Darcy-Forchheimer law. This allows the turbulent velocity and pressure fluctuations to penetrate the bed of discrete particles, and this addition of a porous zone results in turbulence structures above the bed that are similar to previous experimental and numerical results for hydraulically-rough beds. For example, we reproduce low-speed streaks that are less coherent than those over smooth-beds due to the episodic outflow of fluid from the bed. Local resistance terms are also added to the Navier-Stokes equations to account for the drag of individual moving particles. The interaction of the spherical particles utilizes a standard DEM soft-sphere Hertz model. We use only a simple drag model to calculate the fluid forces on the particles. The model reproduces an exponential distribution of bedload particle velocities that we have found experimentally using high-speed video of a flat bed of moving sand in a recirculating water flume. The exponential distribution of velocity results from the motion of many particles that are nearly constantly in contact with other bed particles and come to rest after short distances, in combination with a relatively few particles that are entrained further above the bed and have velocities approaching that of the fluid. Entrainment and motion "hot spots" are evident that are not perfectly correlated with the local, instantaneous fluid velocity. Zones of the bed that have recently experienced motion are more susceptible to motion because of the local configuration of particle contacts. The paradigm of a characteristic saltation hop length in riverine bedload transport has infused many aspects of geomorphic thought, including

  12. Standard test method for determining elements in waste Streams by inductively coupled plasma-atomic emission spectroscopy

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of trace, minor, and major elements in waste streams by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) following an acid digestion of the sample. Waste streams from manufacturing processes of nuclear and non-nuclear materials can be analyzed. This test method is applicable to the determination of total metals. Results from this test method can be used to characterize waste received by treatment facilities and to formulate appropriate treatment recipes. The results are also usable in process control within waste treatment facilities. 1.2 This test method is applicable only to waste streams that contain radioactivity levels that do not require special personnel or environmental protection. 1.3 A list of the elements determined in waste streams and the corresponding lower reporting limit is found in Table 1. 1.4 This test method has been used successfully for treatment of a large variety of waste solutions and industrial process liquids. The com...

  13. A fast linearized conservative finite element method for the strongly coupled nonlinear fractional Schrödinger equations

    Science.gov (United States)

    Li, Meng; Gu, Xian-Ming; Huang, Chengming; Fei, Mingfa; Zhang, Guoyu

    2018-04-01

    In this paper, a fast linearized conservative finite element method is studied for solving the strongly coupled nonlinear fractional Schrödinger equations. We prove that the scheme preserves both the mass and energy, which are defined by virtue of some recursion relationships. Using the Sobolev inequalities and then employing the mathematical induction, the discrete scheme is proved to be unconditionally convergent in the sense of L2-norm and H α / 2-norm, which means that there are no any constraints on the grid ratios. Then, the prior bound of the discrete solution in L2-norm and L∞-norm are also obtained. Moreover, we propose an iterative algorithm, by which the coefficient matrix is independent of the time level, and thus it leads to Toeplitz-like linear systems that can be efficiently solved by Krylov subspace solvers with circulant preconditioners. This method can reduce the memory requirement of the proposed linearized finite element scheme from O (M2) to O (M) and the computational complexity from O (M3) to O (Mlog ⁡ M) in each iterative step, where M is the number of grid nodes. Finally, numerical results are carried out to verify the correction of the theoretical analysis, simulate the collision of two solitary waves, and show the utility of the fast numerical solution techniques.

  14. Possibilities of High Resolution Inductively Coupled Plasma Optical Emission Spectrometry in the Determination of Trace Elements in Environmental Materials

    Directory of Open Access Journals (Sweden)

    Nikolaya Velitchkova

    2013-01-01

    Full Text Available This paper presents new quantitative data for the spectral interferences obtained by high resolution 40.68 MHz radial viewing inductively coupled plasma optical emission spectrometry (HR-ICP-OES in the determination of Zn, Cd, Sb, Cu, Mn, Pb, Sn, Cr, U, and Ba in environmental materials in the presence of a complex matrix, containing Al, Ca, Fe, Mg, and Ti. The -concept for quantification of spectral interferences was used. The optimum line selection for trace analysis of a variety of multicomponent matrices requires the choice of prominent lines, which are free or negligibly influenced by line interference problems. The versatility of -concept as basic methodology was experimentally demonstrated in the determination of trace of elements in soil and drinking water. The detection limits are lower in comparison with corresponding threshold concentration levels for soil and drinking water in accordance with environmental regulations. This paper shows the possibilities of present day ICP-OES equipment in the direct determination of trace elements (without preconcentration of impurities in environmental samples.

  15. [Inductively coupled plasma mass spectrometry for the simultaneous determination of thirty metals and metalloids elements in blood samples].

    Science.gov (United States)

    Ding, Chun-guang; Zhu, Chun; Liu, De-ye; Dong, Ming; Zhang, Ai-hua; Pan, Ya-juan; Yan, Hui-fang

    2012-08-01

    To establish an inductively coupled plasma mass spectrometry(ICP-MS) method for determination of 30 trace elements including As, Ba, Be, Bi, Ni, Cd, Co, Cr, Cs, Cu, Ga, Mn, Pb, Sr, Tl, V, Ge, Mo, Nb, Ti, W, Te, Se, Zr, In, Sb, Hg, Ce, La, and Sm in human blood. The blood samples were analyzed by ICP-MS after diluted 1/10 with 0.01% Triton-X-100 and 0.5% nitric acid solution. Y, Rh and Lu were selected as internal standard in order to correct the matrix interference of Cr, As, Se, and Hg by a hex pole-based collision-reaction cell. Other elements were determined with standard method. The limits of detection, precision and accuracy of the method were evaluated. The accuracy was validated by the determination of the whole blood reference material. All the 30 trace elements have good linearity in their determination range, with the correlation coefficient > 0.9999. The limits of detection of the 30 trace elements were in the range of 1.19 - 2.15 µg/L and the intra-precision and inter-precision (relative standard deviation, RSD) were less than 14.3% (except Hg RSD < 21.2%, and Ni RSD < 15.4%). The spiked recovery for all elements fell within 59.3% - 119.2%. Among the 13 whole blood reference materials, V, Cr, Mn, Co, Ni, Cu, As, Se, Cd, Te, and Pb (1.45, 1.19, 18.40, 0.18, 1.57, 591.00, 2.97, 61.00, 0.35, 1.86, and 9.70 µg/L respectively) fell within the acceptable range and the detection results of Hg (0.59 µg/L) and Mo (1.59 µg/L) were slightly beyond the range. This method was simple, fast and effective. It can be used to monitor the multi-elementary concentration in human blood.

  16. Determination of nutrients and potentially toxic elements in Jatropha curcas seeds, oil and biodiesel using inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Maciel, P.B.; Barros de, L.L.S.; Duarte, E.C.M.; Harder, M.N.C.; Abreu, Jr.C.H.; Villanueva, F.C.A.

    2013-01-01

    Biodiesel is a renewable and biodegradable fuel that can be used in diesel engines as a replacement for fossil diesel. A suitable alternative is to produce it from Jatropha curcas, which has high quality oil concentration. Nevertheless, the presence of particular chemical elements above certain limits can affect the product quality, leading to vehicle engine problems and acting as air pollution source. The objective of this work is to develop a method for the simultaneous determination of B, Na, Mg, P, S, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Ba, and Pb in J. curcas seeds, oil and biodiesel using the inductively coupled plasma mass spectrometry (ICP-MS) technique. This material was evaluated because has been successfully employed in India for biodiesel production as well as in other places where there is an incentive to family farming, without affect the food chain. The oil was obtained from seeds via mechanical extraction and the biodiesel was achieved by oil transesterification. After optimization of the microwave digestion method for the different sample types, the samples were analyzed by ICP-MS. The certified reference material NIST SRM 1515 (apple leaves) and the recovery tests were carried out to ensure the accuracy of the proposed method, which made possible the quantification of several nutrients and potentially toxic elements in J. curcas seeds, oil and biodiesel, especially Na, K, Ca, Mg, P and S in biodiesel which are mandatory analyzed by Petroleum, Natural Gas and Biofuel National Agency (ANP). This work highlights the findings of the first study of potentially toxic and nutrient elements in the production chain steps seed-oil-biodiesel from J. curcas. (author)

  17. Damped gyroscopic effects and axial-flexural-torsional coupling using spinning finite elements for wind-turbine blades characterization

    Science.gov (United States)

    Velazquez, Antonio; Swartz, R. Andrew

    2013-04-01

    Renewable energy sources like wind are important technologies, useful to alleviate for the current fossil-fuel crisis. Capturing wind energy in a more efficient way has resulted in the emergence of more sophisticated designs of wind turbines, particularly Horizontal-Axis Wind Turbines (HAWTs). To promote efficiency, traditional finite element methods have been widely used to characterize the aerodynamics of these types of multi-body systems and improve their design. Given their aeroelastic behavior, tapered-swept blades offer the potential to optimize energy capture and decrease fatigue loads. Nevertheless, modeling special complex geometries requires huge computational efforts necessitating tradeoffs between faster computation times at lower cost, and reliability and numerical accuracy. Indeed, the computational cost and the numerical effort invested, using traditional FE methods, to reproduce dependable aerodynamics of these complex-shape beams are sometimes prohibitive. A condensed Spinning Finite Element (SFE) method scheme is presented in this study aimed to alleviate this issue by means of modeling wind-turbine rotor blades properly with tapered-swept cross-section variations of arbitrary order via Lagrangian equations. Axial-flexural-torsional coupling is carried out on axial deformation, torsion, in-plane bending and out-of-plane bending using super-convergent elements. In this study, special attention is paid for the case of damped yaw effects, expressed within the described skew-symmetric damped gyroscopic matrix. Dynamics of the model are analyzed by achieving modal analysis with complex-number eigen-frequencies. By means of mass, damped gyroscopic, and stiffness (axial-flexural-torsional coupling) matrix condensation (order reduction), numerical analysis is carried out for several prototypes with different tapered, swept, and curved variation intensities, and for a practical range of spinning velocities at different rotation angles. A convergence study

  18. Simultaneous determination of macronutrients, micronutrients and trace elements in mineral fertilizers by inductively coupled plasma optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Souza, Sidnei de [Laboratório de Química Analítica Ambiental (LQA), Departamento de Química, Centro de Ciências Exatas e Tecnologia, Universidade Federal de Sergipe (UFS), 49100-000, São Cristovão, SE (Brazil); Silvério Lopes da Costa, Silvânio [Laboratório de Química Analítica Ambiental (LQA), Departamento de Química, Centro de Ciências Exatas e Tecnologia, Universidade Federal de Sergipe (UFS), 49100-000, São Cristovão, SE (Brazil); Coordenação de Química, Universidade Federal de Alagoas (UFAL), Campus Arapiraca, 57309-005, Arapiraca, AL (Brazil); Santos, Dayane Melo; Santos Pinto, Jéssica dos; Garcia, Carlos Alexandre Borges [Laboratório de Química Analítica Ambiental (LQA), Departamento de Química, Centro de Ciências Exatas e Tecnologia, Universidade Federal de Sergipe (UFS), 49100-000, São Cristovão, SE (Brazil); and others

    2014-06-01

    An analytical method for simultaneous determination of macronutrients (Ca, Mg, Na and P), micronutrients (Cu, Fe, Mn and Zn) and trace elements (Al, As, Cd, Pb and V) in mineral fertilizers was optimized. Two-level full factorial design was applied to evaluate the optimal proportions of reagents used in the sample digestion on hot plate. A Doehlert design for two variables was used to evaluate the operating conditions of the inductively coupled plasma optical emission spectrometer in order to accomplish the simultaneous determination of the analyte concentrations. The limits of quantification (LOQs) ranged from 2.0 mg kg{sup −1} for Mn to 77.3 mg kg{sup −1} for P. The accuracy and precision of the proposed method were evaluated by analysis of standard reference materials (SRMs) of Western phosphate rock (NIST 694), Florida phosphate rock (NIST 120C) and Trace elements in multi-nutrient fertilizer (NIST 695), considered to be adequate for simultaneous determination. Twenty-one samples of mineral fertilizers collected in Sergipe State, Brazil, were analyzed. For all samples, the As, Ca, Cd and Pb concentrations were below the LOQ values of the analytical method. For As, Cd and Pb the obtained LOQ values were below the maximum limit allowed by the Brazilian Ministry of Agriculture, Livestock and Food Supply (Ministério da Agricultura, Pecuária e Abastecimento — MAPA). The optimized method presented good accuracy and was effectively applied to quantitative simultaneous determination of the analytes in mineral fertilizers by inductively coupled plasma optical emission spectrometry (ICP OES). - Highlights: • Determination of inorganic constituents in mineral fertilizers was proposed. • Experimental design methodology was used to optimize analytical method. • The sample preparation procedure using diluted reagents (HNO{sub 3} and H{sub 2}O{sub 2}) was employed. • The analytical method was satisfactorily to the determination of thirteen elements. • The

  19. Optimization of on-line hydrogen stable isotope ratio measurements of halogen- and sulfur-bearing organic compounds using elemental analyzer-chromium/high-temperature conversion isotope ratio mass spectrometry (EA-Cr/HTC-IRMS).

    Science.gov (United States)

    Gehre, Matthias; Renpenning, Julian; Geilmann, Heike; Qi, Haiping; Coplen, Tyler B; Kümmel, Steffen; Ivdra, Natalija; Brand, Willi A; Schimmelmann, Arndt

    2017-03-30

    Accurate hydrogen isotopic analysis of halogen- and sulfur-bearing organics has not been possible with traditional high-temperature conversion (HTC) because the formation of hydrogen-bearing reaction products other than molecular hydrogen (H 2 ) is responsible for non-quantitative H 2 yields and possible hydrogen isotopic fractionation. Our previously introduced, new chromium-based EA-Cr/HTC-IRMS (Elemental Analyzer-Chromium/High-Temperature Conversion Isotope Ratio Mass Spectrometry) technique focused primarily on nitrogen-bearing compounds. Several technical and analytical issues concerning halogen- and sulfur-bearing samples, however, remained unresolved and required further refinement of the reactor systems. The EA-Cr/HTC reactor was substantially modified for the conversion of halogen- and sulfur-bearing samples. The performance of the novel conversion setup for solid and liquid samples was monitored and optimized using a simultaneously operating dual-detection system of IRMS and ion trap MS. The method with several variants in the reactor, including the addition of manganese metal chips, was evaluated in three laboratories using EA-Cr/HTC-IRMS (on-line method) and compared with traditional uranium-reduction-based conversion combined with manual dual-inlet IRMS analysis (off-line method) in one laboratory. The modified EA-Cr/HTC reactor setup showed an overall H 2 -recovery of more than 96% for all halogen- and sulfur-bearing organic compounds. All results were successfully normalized via two-point calibration with VSMOW-SLAP reference waters. Precise and accurate hydrogen isotopic analysis was achieved for a variety of organics containing F-, Cl-, Br-, I-, and S-bearing heteroelements. The robust nature of the on-line EA-Cr/HTC technique was demonstrated by a series of 196 consecutive measurements with a single reactor filling. The optimized EA-Cr/HTC reactor design can be implemented in existing analytical equipment using commercially available material and

  20. Coupling of modal and finite elements methods for the diffraction of guided elastics waves: application to non destructive testing

    International Nuclear Information System (INIS)

    Baronian, V.

    2009-11-01

    A typical nondestructive examination based on guided elastic waves can be simulated by considering an elastic 2D (a plate) or 3D (a rod) guide that contains a defect (a crack, a local heterogeneity due to a weld etc.). Our aim is to solve numerically the problem of the scattering by a defect of a mode propagating in a guide. This has been achieved by developing a method that couples i) finite elements in the smallest possible region of the guide that contains the defect, with ii) the modal decomposition of waves outside this region. The main challenge consists in finding the right linking condition of both representations. A decisive tool is the obtaining of an orthogonality relation which makes it possible to project the finite element solution onto guided modes. For this, the problem is formulated in terms of hybrid vectors (displacement/stress) for which a bi-orthogonality relation exists, namely, the Fraser's relation. It is then possible to derive an exact (transparent) condition on the artificial boundaries of the finite element domain; the modal series taken into account being necessarily truncated, transparency is achieved only approximately. Eventually, this boundary condition is integrated in a variational approach (in terms of displacement) in order to develop a finite element method. The transparent boundary condition being expressed in terms of the hybrid vectors, the stress normal to the artificial boundary is introduced as a supplementary unknown, together with a mixed formulation. Both 2D and 3D isotropic guides with free boundary conditions have been considered numerically. Guided modes are computed thanks to an original modeling approach also based on the hybrid (displacement/stress) vectors; interestingly, bi-orthogonality relation expressed in a discrete form is preserved. The code implementing these methods leads to fast computations of the scattering matrix of a defect; once this matrix has been computed at various frequencies, the defect

  1. Coupled Vortex-Lattice Flight Dynamic Model with Aeroelastic Finite-Element Model of Flexible Wing Transport Aircraft with Variable Camber Continuous Trailing Edge Flap for Drag Reduction

    Science.gov (United States)

    Nguyen, Nhan; Ting, Eric; Nguyen, Daniel; Dao, Tung; Trinh, Khanh

    2013-01-01

    This paper presents a coupled vortex-lattice flight dynamic model with an aeroelastic finite-element model to predict dynamic characteristics of a flexible wing transport aircraft. The aircraft model is based on NASA Generic Transport Model (GTM) with representative mass and stiffness properties to achieve a wing tip deflection about twice that of a conventional transport aircraft (10% versus 5%). This flexible wing transport aircraft is referred to as an Elastically Shaped Aircraft Concept (ESAC) which is equipped with a Variable Camber Continuous Trailing Edge Flap (VCCTEF) system for active wing shaping control for drag reduction. A vortex-lattice aerodynamic model of the ESAC is developed and is coupled with an aeroelastic finite-element model via an automated geometry modeler. This coupled model is used to compute static and dynamic aeroelastic solutions. The deflection information from the finite-element model and the vortex-lattice model is used to compute unsteady contributions to the aerodynamic force and moment coefficients. A coupled aeroelastic-longitudinal flight dynamic model is developed by coupling the finite-element model with the rigid-body flight dynamic model of the GTM.

  2. Determination of the mineral compositions of some selected oil-bearing seeds and kernels using Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES

    Directory of Open Access Journals (Sweden)

    Musa Özcan, M.

    2006-06-01

    Full Text Available The aim of this paper was to establish the mineral contents of oil-bearing seeds and kernels such as peanut, turpentine, walnut, hazelnut, sesame, corn, poppy, almond, sunflower etc., using Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES. Significant differences in mineral composition were observed among crops. All seeds and kernels contained high amounts of Al, Ca, Fe, K, Mg, Na, P and Zn. B, Cr, Cu, Li, Ni, Sr, Ti while V contents of the crops were found to be very low. The levels of K and P of all crops in this study were found to be higher than those of other seeds and kernels. The results obtained from analyses of the crops showed that the mean levels of potassiumcontent ranged from 1701.08 mg/kg (corn to 20895.8 mg/kg (soybean, the average content of phosphorus ranged from 3076.9 mg/kg (turpentine to 12006,5 mg/kg to 2617.4 mg/kg (cotton seed, and Ca from 68.4 mg/kg (corn to 13195.7 mg/kg (poppy seed. The results show that these values may  be useful for the evaluation of dietary information. Particularly the obtained results provide evidence that soybean, pinestone and poppy seed are a good source of K, P and Ca, respectively. Whereas pinestone is a good source of zinc.La finalidad del trabajo es establecer el contenido en elementos minerales de semillas oleaginosas tales como cacahuetes, trementina, avellana, sesamo, maiz, almendras, girasol, utilizando ICP-AES. Se han observado diferencias significativas en la composición de minerales entre cosechas. Todas las semillas contienen cantidades elevadas de Al, Ca, Fe, K, Mg, Na, P y Zn. Los contenidos de B, Cr, Cu, Li, Ni, Sr, Ti y V, sin embargo, fueron bajos. Los contenidos de K y P en todas las semillas estudiadas fueron superiores a las de otras semillas. El contenido medio de K osciló entre 1.701,1 mg/kg (maiz a 20.895,8 mg/kg (soja, el P entre 3.076.9 mg/kg (trementina a 12.006.5 mg/kg o 2.617,4 mg/kg (semilla de algodón, y Ca de 68,4 mg/kg (maiz a 13.195,7 mg

  3. 2D elemental mapping of sections of human kidney stones using laser ablation inductively-coupled plasma-mass spectrometry: Possibilities and limitations

    Energy Technology Data Exchange (ETDEWEB)

    Vašinová Galiová, Michaela [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, 625 00 Brno (Czech Republic); Čopjaková, Renata; Škoda, Radek [Department of Geological Sciences, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Štěpánková, Kateřina; Vaňková, Michaela [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Kuta, Jan [Research Centre for Toxic Compounds in the Environment (RECETOX), Masaryk University, Kamenice 126/3, 625 00 Brno (Czech Republic); Prokeš, Lubomír [Department of Chemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno (Czech Republic); Kynický, Jindřich [Department of Pedology and Geology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno (Czech Republic); and others

    2014-10-01

    A 213 nm Nd:YAG-based laser ablation (LA) system coupled to quadrupole-based inductively coupled plasma-mass spectrometer and an ArF* excimer-based LA-system coupled to a double-focusing sector field inductively coupled plasma-mass spectrometer were employed to study the spatial distribution of various elements in kidney stones (uroliths). Sections of the surfaces of uroliths were ablated according to line patterns to investigate the elemental profiles for the different urolith growth zones. This exploratory study was mainly focused on the distinguishing of the main constituents of urinary calculus fragments by means of LA-ICP-mass spectrometry. Changes in the ablation rate for oxalate and phosphate phases related to matrix density and hardness are discussed. Elemental association was investigated on the basis of 2D mapping. The possibility of using NIST SRM 1486 Bone Meal as an external standard for calibration was tested. It is shown that LA-ICP-MS is helpful for determination of the mineralogical composition and size of all phases within the analyzed surface area, for tracing down elemental associations and for documenting the elemental content of urinary stones. LA-ICP-MS results (elemental contents and maps) are compared to those obtained with electron microprobe analysis and solution analysis ICP-MS. - Highlights: • Elements in phosphate and oxalate urolith phases were quantified by LA-ICP-MS. • SRM NIST 1486 Bone Meal was proved suitable for quantification in uroliths. • Different ablation rates in particular phases were included at quantification. • Oxalate and apatite phases show opposite hardness order to natural minerals. • Uroliths were classified according to elemental association to phases.

  4. Coupling of a continuum ice sheet model and a discrete element calving model using a scientific workflow system

    Science.gov (United States)

    Memon, Shahbaz; Vallot, Dorothée; Zwinger, Thomas; Neukirchen, Helmut

    2017-04-01

    Scientific communities generate complex simulations through orchestration of semi-structured analysis pipelines which involves execution of large workflows on multiple, distributed and heterogeneous computing and data resources. Modeling ice dynamics of glaciers requires workflows consisting of many non-trivial, computationally expensive processing tasks which are coupled to each other. From this domain, we present an e-Science use case, a workflow, which requires the execution of a continuum ice flow model and a discrete element based calving model in an iterative manner. Apart from the execution, this workflow also contains data format conversion tasks that support the execution of ice flow and calving by means of transition through sequential, nested and iterative steps. Thus, the management and monitoring of all the processing tasks including data management and transfer of the workflow model becomes more complex. From the implementation perspective, this workflow model was initially developed on a set of scripts using static data input and output references. In the course of application usage when more scripts or modifications introduced as per user requirements, the debugging and validation of results were more cumbersome to achieve. To address these problems, we identified a need to have a high-level scientific workflow tool through which all the above mentioned processes can be achieved in an efficient and usable manner. We decided to make use of the e-Science middleware UNICORE (Uniform Interface to Computing Resources) that allows seamless and automated access to different heterogenous and distributed resources which is supported by a scientific workflow engine. Based on this, we developed a high-level scientific workflow model for coupling of massively parallel High-Performance Computing (HPC) jobs: a continuum ice sheet model (Elmer/Ice) and a discrete element calving and crevassing model (HiDEM). In our talk we present how the use of a high

  5. Determination of rare earth elements in environmental matrices by sector-field inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Riondato, J; Vanhaecke, F; Moens, L; Dams, R

    2001-07-01

    In the framework of an international certification campaign, sector-field inductively coupled plasma mass spectrometry (sector-field ICP-MS) was used for the accurate determination of the rare earth elements in five candidate reference materials: aquatic plant, calcareous soil, mussel tissue, river sediment, and tuna muscle. All samples were taken into solution by use of microwave-assisted or mixed microwave-assisted / open beaker acid digestion. Subsequently, the samples were appropriately diluted and subjected to ICP-MS analysis. Except for Sc, all the elements involved were determined at low mass resolution (R = 300). For Sc, application of a higher resolution setting (R = 3,000) was required to separate the analyte signal from those of several molecular ions which gave rise to spectral overlap at low mass resolution. Some of the heavier REE can also suffer from spectral overlap attributed to the occurrence of oxide ions (MO+) of the lighter REE and Ba. This spectral overlap could be successfully overcome by mathematical correction. Matrix effects were overcome by use of two carefully selected internal standards, such that external calibration could be used. On each occasion, a geological reference material was analyzed as a quality-control sample and the reliability of all results obtained was additionally checked by means of chondrite normalization. For tuna muscle the content of all REE was below the limit of detection. For calcareous soil and river sediment, low to sub microg g(-1) values were observed, whereas the REE content of aquatic plant and mussel tissue was considerably lower (low to sub ng g(-1)). Overall, the results obtained were in excellent agreement with the average values, calculated on the basis of all "accepted" values, obtained in different laboratories using different techniques.

  6. Feasibility of Applying Controllable Lubrication to Dynamically Loaded Journal Bearings

    DEFF Research Database (Denmark)

    Estupinan, Edgar Alberto; Santos, Ilmar

    2009-01-01

    A multibody dynamic model of the main mechanical components of a hermetic reciprocating compressor is presented in this work. Considering that some of the mechanical elements are interconnected via thin fluid films, the multibody dynamic model is coupled to the equations from the dynamics...... of the fluid films, based on fluid film theory. For a dynamically loaded journal bearing, the fluid film pressure distribution can be computed by numerically solving the Reynolds equation, by means of finite-difference method. Particularly, in this study the main focus is on the lubrication behavior...... and reaction forces in a reciprocating compressor have a cyclic behavior, periodic oil pressure injection rules based on the instantaneous crank angle and load bearing condition can be established. In this paper, several bearing configurations working under different oil pressure injection rules conditions...

  7. Cool Polar Bears: Dabbing on the Texture

    Science.gov (United States)

    O'Connell, Jean

    2011-01-01

    In this article, the author describes how her second-graders created their cool polar bears. The students used the elements of shape and texture to create the bears. They used Monet's technique of dabbing paint so as to give the bear some texture on his fur.

  8. Finite Element Modeling of Dieless Tube Drawing of Strain Rate Sensitive Material with Coupled Thermo-Mechanical Analysis

    Science.gov (United States)

    Furushima, Tsuyoshi; Sakai, Takashi; Manabe, Ken-ichi

    2004-06-01

    Dieless drawing is a unique deformation process without conventional dies, which can achieve a great reduction of wire and tube metals in single pass by means of local heating and cooling approach. In this study, for microtube forming, the dieless drawing process applying superplastic behavior was analyzed by finite element method (FEM) in order to clarify the effect of dieless tube drawing conditions such as tensile speed, moving speed of heating and cooling system, and material properties on deformation behavior of the tube. In the calculation, the material properties were dealt in a special subroutine, whose constitutive equation was defined as σ = Kɛnɛ˙m, and was linked to the solver. A coupled thermo-mechanical analysis was performed for the dieless tube drawing using the FEM. In the thermal analysis of dieless tube drawing, heat transfer was introduced to calculate the heat flux between heating coil and tube surface, and heat conduction in a tube. The influence of dieless tube drawing conditions on deformation behavior was clarified. As a result, for the strain rate sensitive material, the maximum reduction of area and the minimum outer diameter in single pass attain to 90.9% and 2.56mm, respectively. From the result, it is concluded that the dieless tube drawing is essential to produce an extrafine microtube by reason of keeping cylindrical tube diameter ratio constant with extremely high reduction.

  9. Static Aeroelastic and Longitudinal Trim Model of Flexible Wing Aircraft Using Finite-Element Vortex-Lattice Coupled Solution

    Science.gov (United States)

    Ting, Eric; Nguyen, Nhan; Trinh, Khanh

    2014-01-01

    This paper presents a static aeroelastic model and longitudinal trim model for the analysis of a flexible wing transport aircraft. The static aeroelastic model is built using a structural model based on finite-element modeling and coupled to an aerodynamic model that uses vortex-lattice solution. An automatic geometry generation tool is used to close the loop between the structural and aerodynamic models. The aeroelastic model is extended for the development of a three degree-of-freedom longitudinal trim model for an aircraft with flexible wings. The resulting flexible aircraft longitudinal trim model is used to simultaneously compute the static aeroelastic shape for the aircraft model and the longitudinal state inputs to maintain an aircraft trim state. The framework is applied to an aircraft model based on the NASA Generic Transport Model (GTM) with wing structures allowed to flexibly deformed referred to as the Elastically Shaped Aircraft Concept (ESAC). The ESAC wing mass and stiffness properties are based on a baseline "stiff" values representative of current generation transport aircraft.

  10. A cut-cell finite volume - finite element coupling approach for fluid-structure interaction in compressible flow

    Science.gov (United States)

    Pasquariello, Vito; Hammerl, Georg; Örley, Felix; Hickel, Stefan; Danowski, Caroline; Popp, Alexander; Wall, Wolfgang A.; Adams, Nikolaus A.

    2016-02-01

    We present a loosely coupled approach for the solution of fluid-structure interaction problems between a compressible flow and a deformable structure. The method is based on staggered Dirichlet-Neumann partitioning. The interface motion in the Eulerian frame is accounted for by a conservative cut-cell Immersed Boundary method. The present approach enables sub-cell resolution by considering individual cut-elements within a single fluid cell, which guarantees an accurate representation of the time-varying solid interface. The cut-cell procedure inevitably leads to non-matching interfaces, demanding for a special treatment. A Mortar method is chosen in order to obtain a conservative and consistent load transfer. We validate our method by investigating two-dimensional test cases comprising a shock-loaded rigid cylinder and a deformable panel. Moreover, the aeroelastic instability of a thin plate structure is studied with a focus on the prediction of flutter onset. Finally, we propose a three-dimensional fluid-structure interaction test case of a flexible inflated thin shell interacting with a shock wave involving large and complex structural deformations.

  11. A cut-cell finite volume – finite element coupling approach for fluid–structure interaction in compressible flow

    International Nuclear Information System (INIS)

    Pasquariello, Vito; Hammerl, Georg; Örley, Felix; Hickel, Stefan; Danowski, Caroline; Popp, Alexander; Wall, Wolfgang A.; Adams, Nikolaus A.

    2016-01-01

    We present a loosely coupled approach for the solution of fluid–structure interaction problems between a compressible flow and a deformable structure. The method is based on staggered Dirichlet–Neumann partitioning. The interface motion in the Eulerian frame is accounted for by a conservative cut-cell Immersed Boundary method. The present approach enables sub-cell resolution by considering individual cut-elements within a single fluid cell, which guarantees an accurate representation of the time-varying solid interface. The cut-cell procedure inevitably leads to non-matching interfaces, demanding for a special treatment. A Mortar method is chosen in order to obtain a conservative and consistent load transfer. We validate our method by investigating two-dimensional test cases comprising a shock-loaded rigid cylinder and a deformable panel. Moreover, the aeroelastic instability of a thin plate structure is studied with a focus on the prediction of flutter onset. Finally, we propose a three-dimensional fluid–structure interaction test case of a flexible inflated thin shell interacting with a shock wave involving large and complex structural deformations.

  12. Coupled finite difference and boundary element methods for fluid flow through a vessel with multibranches in tumours.

    Science.gov (United States)

    Sun, Qiang; Wu, Guo Xiong

    2013-03-01

    A mathematical model and a numerical solution procedure are developed to simulate flow field through a 3D permeable vessel with multibranches embedded in a solid tumour. The model is based on Poisseuille's law for the description of the flow through the vessels, Darcy's law for the fluid field inside the tumour interstitium, and Starling's law for the flux transmitted across the vascular walls. The solution procedure is based on a coupled method, in which the finite difference method is used for the flow in the vessels and the boundary element method is used for the flow in the tumour. When vessels meet each other at a junction, the pressure continuity and mass conservation are imposed at the junction. Three typical representative structures within the tumour vasculature, symmetrical dichotomous branching, asymmetrical bifurcation with uneven radius of daughter vessels and trifurcation, are investigated in detail as case studies. These results have demonstrated the features of tumour flow environment by the pressure distributions and flow velocity field. Copyright © 2012 John Wiley & Sons, Ltd.

  13. Stress analysis on the valve of the rotating shield, coupled with fuel element loading-unloading machine in a PWR pressure vessel

    International Nuclear Information System (INIS)

    Albuquerque, L.B. de; Jesus Miranda, C.A. de.

    1992-01-01

    A finite element static analysis was performed with the valve of the Rotating Shield (RS) which is coupled with the Fuel. Element Loading-Unloading Machine under OBE earthquake. The applied leads were obtained from a previous seismic analysis with the response spectrum method of the MTC under OBE load. A 3-D model with shell elements was developed for the valve body and for a part of the RS. The ANSYS program, version 4.4 A, was used. The two main scopes of this work were to verify the valve stresses and the functionality of its moving parts during the earthquake. (author)

  14. Mass separation of rare-earth elements by a high-temperature thermal ion source coupled with a He-jet system

    International Nuclear Information System (INIS)

    Kawase, Y.; Okano, K.; Aoki, K.

    1987-01-01

    By using a high-temperature thermal ion source coupled to a He-jet system, neutron-rich isotopes of rare-earth elements such as cerium, praseodymium, neodymium and promethium produced by the thermal-neutron fission of /sup 235/U were ionized and successfully separated. The temperature dependence of the ionization efficiency has been measured and found to be explained qualitatively by the vapour pressure of the relevant elements. The characteristic temperature dependence of the ionization efficiency has been utilized for Z-identification of several isobars of rare-earth elements. The heaviest isotopes of neodymium and promethium, /sup 155/Nd and /sup 156/Pm, have recently been identified

  15. Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Menendez-Miranda, Mario; Fernandez-Arguelles, Maria T.; Costa-Fernandez, Jose M.; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo

    2014-01-01

    Highlights: • The hyphenated system allows unequivocal identification of nanoparticle populations. • AF4 separation permitted detection of unexpected nanosized species in a sample. • ICP-QQQ provides elemental ratios with adequate accuracy in every nanoparticle. • Purity and chemical composition of different quantum dot samples were assessed. - Abstract: Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches

  16. Gaseous byproducts from high-temperature thermal conversion elemental analysis of nitrogen- and sulfur-bearing compounds with considerations for δ2H and δ18O analyses.

    Science.gov (United States)

    Hunsinger, Glendon B; Tipple, Christopher A; Stern, Libby A

    2013-07-30

    High-temperature, conversion-reduction (HTC) systems convert hydrogen and oxygen in materials into H2 and CO for δ(2)H and δ(18)O measurements by isotope ratio mass spectrometry. HTC of nitrogen- and sulfur-bearing materials produces unintended byproduct gases that could affect isotope analyses by: (1) allowing isotope exchange reactions downstream of the HTC reactor, (2) creating isobaric or co-elution interferences, and (3) causing deterioration of the chromatography. This study characterizes these HTC byproducts. A HTC system (ThermoFinnigan TC/EA) was directly connected to a gas chromatograph/quadrupole mass spectrometer in scan mode (m/z 8 to 88) to identify the volatile products generated by HTC at conversion temperatures of 1350 °C and 1450 °C for a range of nitrogen- and sulfur-bearing solids [keratin powder, horse hair, caffeine, ammonium nitrate, potassium nitrate, ammonium sulfate, urea, and three nitrated organic explosives (PETN, RDX, and TNT)]. The prominent HTC byproduct gases include carbon dioxide, hydrogen cyanide, methane, acetylene, and water for all nitrogen-bearing compounds, as well as carbon disulfide, carbonyl sulfide, and hydrogen sulfide for sulfur-bearing compounds. The 1450 °C reactor temperature reduced the abundance of most byproduct gases, but increased the significant byproduct, hydrogen cyanide. Inclusion of a post-reactor chemical trap containing Ascarite II and Sicapent, in series, eliminated the majority of byproducts. This study identified numerous gaseous HTC byproducts. The potential adverse effects of these gases on isotope ratio analyses are unknown but may be mitigated by higher HTC reactor temperatures and purifying the products with a purge-and-trap system or with chemical traps. Published in 2013. This article is a U.S. Government work and is in the public domain in the USA.

  17. TOOL ASSEMBLY WITH BI-DIRECTIONAL BEARING

    Science.gov (United States)

    Longhurst, G.E.

    1961-07-11

    A two-direction motion bearing which is incorporated in a refueling nuclear fuel element trsnsfer tool assembly is described. A plurality of bi- directional bearing assembliesare fixed equi-distantly about the circumference of the transfer tool assembly to provide the tool assembly with a bearing surface- for both axial and rotational motion. Each bi-directional bearing assembly contains a plurality of circumferentially bulged rollers mounted in a unique arrangement which will provide a bearing surface for rotational movement of the tool assembly within a bore. The bi-direc tional bearing assembly itself is capable of rational motion and thus provides for longitudinal movement of the tool assembly.

  18. Free Vibration Analysis of a Spinning Flexible DISK-SPINDLE System Supported by Ball Bearing and Flexible Shaft Using the Finite Element Method and Substructure Synthesis

    Science.gov (United States)

    JANG, G. H.; LEE, S. H.; JUNG, M. S.

    2002-03-01

    Free vibration of a spinning flexible disk-spindle system supported by ball bearing and flexible shaft is analyzed by using Hamilton's principle, FEM and substructure synthesis. The spinning disk is described by using the Kirchhoff plate theory and von Karman non-linear strain. The rotating spindle and stationary shaft are modelled by Rayleigh beam and Euler beam respectively. Using Hamilton's principle and including the rigid body translation and tilting motion, partial differential equations of motion of the spinning flexible disk and spindle are derived consistently to satisfy the geometric compatibility in the internal boundary between substructures. FEM is used to discretize the derived governing equations, and substructure synthesis is introduced to assemble each component of the disk-spindle-bearing-shaft system. The developed method is applied to the spindle system of a computer hard disk drive with three disks, and modal testing is performed to verify the simulation results. The simulation result agrees very well with the experimental one. This research investigates critical design parameters in an HDD spindle system, i.e., the non-linearity of a spinning disk and the flexibility and boundary condition of a stationary shaft, to predict the free vibration characteristics accurately. The proposed method may be effectively applied to predict the vibration characteristics of a spinning flexible disk-spindle system supported by ball bearing and flexible shaft in the various forms of computer storage device, i.e., FDD, CD, HDD and DVD.

  19. The use of inductively coupled plasma mass spectrometry (ICP-MS) for the determination of toxic and essential elements in different types of food samples

    Science.gov (United States)

    Voica, C.; Dehelean, A.; Kovacs, M. H.

    2012-02-01

    Food is the primary source of essential elements for humans and it is an important source of exposure to toxic elements. In this context, levels of essential and toxic elements must be determined routinely in consumed food products. The content of trace elements (As, Pb, Cu, Cd, Zn, Sn, Hg) in different types of food samples (e.g. rice, bread, sugar, cheese, milk, butter, wheat, coffee, chocolate, biscuits pasta, etc.) was determined, using inductively coupled plasma mass spectrometry (ICP-MS). Trace element contents in some foods were higher than maximum permissible levels of toxic metals in human food (Cd in bread, Zn in cheese, Cu in coffee, Hg in carrots and peppers).

  20. Modeling of a fluid-loaded smart shell structure for active noise and vibration control using a coupled finite element–boundary element approach

    International Nuclear Information System (INIS)

    Ringwelski, S; Gabbert, U

    2010-01-01

    A recently developed approach for the simulation and design of a fluid-loaded lightweight structure with surface-mounted piezoelectric actuators and sensors capable of actively reducing the sound radiation and the vibration is presented. The objective of this paper is to describe the theoretical background of the approach in which the FEM is applied to model the actively controlled shell structure. The FEM is also employed to model finite fluid domains around the shell structure as well as fluid domains that are partially or totally bounded by the structure. Boundary elements are used to characterize the unbounded acoustic pressure fields. The approach presented is based on the coupling of piezoelectric and acoustic finite elements with boundary elements. A coupled finite element–boundary element model is derived by introducing coupling conditions at the fluid–fluid and fluid–structure interfaces. Because of the possibility of using piezoelectric patches as actuators and sensors, feedback control algorithms can be implemented directly into the multi-coupled structural–acoustic approach to provide a closed-loop model for the design of active noise and vibration control. In order to demonstrate the applicability of the approach developed, a number of test simulations are carried out and the results are compared with experimental data. As a test case, a box-shaped shell structure with surface-mounted piezoelectric actuators and four sensors and an open rearward end is considered. A comparison between the measured values and those predicted by the coupled finite element–boundary element model shows a good agreement

  1. Transient Vibration Prediction for Rotors on Ball Bearings Using Load-dependent Non-linear Bearing Stiffness

    Science.gov (United States)

    Fleming, David P.; Poplawski, J. V.

    2002-01-01

    Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus an accurate rotordynamic transient analysis requires bearing forces to be determined at each step of the transient solution. Analyses have been carried out to show the effect of accurate bearing transient forces (accounting for non-linear speed and load dependent bearing stiffness) as compared to conventional use of average rolling-element bearing stiffness. Bearing forces were calculated by COBRA-AHS (Computer Optimized Ball and Roller Bearing Analysis - Advanced High Speed) and supplied to the rotordynamics code ARDS (Analysis of Rotor Dynamic Systems) for accurate simulation of rotor transient behavior. COBRA-AHS is a fast-running 5 degree-of-freedom computer code able to calculate high speed rolling-element bearing load-displacement data for radial and angular contact ball bearings and also for cylindrical and tapered roller beatings. Results show that use of nonlinear bearing characteristics is essential for accurate prediction of rotordynamic behavior.

  2. Macro- and micro-element analysis in milk samples by inductively coupled plasma-optical emission spectrometry

    Directory of Open Access Journals (Sweden)

    Petrović Sanja M.

    2016-01-01

    Full Text Available The paper describes the determination of Ag, Al, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, In, K, Li, Mg, Mn, Na, Ni, Pb, Sr, Tl and Zn, as well as total fat content of milk samples, originated from different sources. The analyzed milk samples were: human milk, fresh cow milk, pasteurized cow milk from a local market, and reconstituted powder milk. The milk samples were obtained from Jablanica District (Serbia territory. Preparation of samples for macro- and micro-analyses was done by wet digestion. Concentrations of the elements after digestion were determined by inductively coupled plasma optical emission spectrometry (ICP-OES. Total fat content of milk samples was determinate by the Weibull and Stoldt method. The results showed that potassium and calcium concentrations were the highest in all samples: 1840.64 - 2993.26 mg/L and 456.05 - 1318.08 mg/L, respectively. Of all heavy metals from the examined milk samples (copper, zinc, manganese, nickel, cadmium, and lead, the most common were zinc and copper, with approximately similar content in the range of 5 - 12 mg/l, while cadmium nickel and manganese were not detected at all. Samples of fresh cow milk and human milk showed the highest fat content of 3.6 and 4.2 %, respectively. Results for total fat and macro- and micro-analyses showed that fresh cow milk has the highest contents of fat and calcium, making it the most nutritious. [Projekat Ministarstva nauke Republike Srbije, br. TR 34012

  3. Investigation of multi-stage cold forward extrusion process using coupled thermo-mechanical finite element analysis

    Science.gov (United States)

    Görtan, Mehmet Okan

    2018-05-01

    Cold extrusion processes are distinguished by their low material usage as well as great efficiency in the production of mid-range and large component series. Although majority of the cold extruded parts are produced using die systems containing multiple forming stages, this subject has rarely been investigated so far. Therefore, the characteristics of multi-stage cold forward rod extrusion is studied in the current work using thermo-mechanically coupled finite element (FE) analysis. A case hardening steel, 16MnCr5 (1.7131) was used as experimental material. Its strain, strain rate and temperature dependent mechanical characteristics were determined using compression testing and modeled in FE simulations via a Johnson-Cook material model. Friction coefficients for the same material while in contact with a tool steel (1.2379) were determined dependent on temperature and contact pressure using sliding compression test (SCT) and modeled by an adaptive friction model developed by the author. In the first set of simulations, rod material with a diameter of 14.9 mm was extruded down to a diameter of 9.6 mm in a single step using three different die opening angles (2α); 20°, 40° and 60°. In the second set of investigations, the same rod was reduced first to 12 mm and then to 9.6 mm in two steps within the same forming die. Press forces, contact normal stresses between extruded material and forming die, material temperature and axial stresses are compared in these two set of simulations and the differences are discussed.

  4. Environmental application of elemental speciation analysis based on liquid or gas chromatography hyphenated to inductively coupled plasma mass spectrometry-A review

    International Nuclear Information System (INIS)

    Popp, Maximilian; Hann, Stephan; Koellensperger, Gunda

    2010-01-01

    In recent years the number of environmental applications of elemental speciation analysis using inductively coupled plasma mass spectrometry (ICP-MS) as detector has increased significantly. The analytical characteristics, such as extremely low detection limits (LOD) for almost all elements, the wide linear range, the possibility for multi-elemental analysis and the possibility to apply isotope dilution mass spectrometry (IDMS) make ICP-MS an attractive tool for elemental speciation analysis. Two methodological approaches, i.e. the combination of ICP-MS with high performance liquid chromatography (HPLC) and gas chromatography (GC), dominate the field. Besides the investigation of metals and metalloids and their species (e.g. Sn, Hg, As), representing 'classic' elements in environmental science, more recently other elements (e.g. P, S, Br, I) amenable to ICP-MS determination were addressed. In addition, the introduction of isotope dilution analysis and the development of isotopically labeled species-specific standards have contributed to the success of ICP-MS in the field. The aim of this review is to summarize these developments and to highlight recent trends in the environmental application of ICP-MS coupled to GC and HPLC.

  5. Trace element determination in seawater by ICP-SFMS coupled with a microflow nebulization/desolvation system

    International Nuclear Information System (INIS)

    Turetta, Clara; Cozzi, Giulio; Barbante, Carlo; Capodaglio, Gabriele; Cescon, Paolo

    2004-01-01

    Direct and simultaneous determination of Al, Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Pb, Sb, U, V and Zn in diluted (1:10 v:v) seawater from the Antarctic Ocean and the Venice Lagoon at the ng mL -1 and pg mL -1 level has been performed by using an inductively coupled plasma sector field mass spectrometer (ICP-SFMS). Samples were analysed by using a PFA microflow nebulizer coupled with a desolvation system or a PFA microflow nebulizer coupled with a Teflon spray chamber, respectively. Measurements were carried out at low (LR, m/Δm=300), medium (MR, m/Δm=3,000) and high (HR, m/Δm=7,500) resolutions depending on the studied isotope. To avoid contamination, sample pre-treatment was carried out in a clean laboratory equipped with a Class 100 vertical laminar flow hood. Concentration ranges (minimum-maximum in ng mL -1 ) found in the Antarctic seawater samples (in depth profiles) were: Ag 0.0004-0.0018, As 0.69-1.32, Cd 0.031-0.096, Co 0.018-0.065, Cr 0.18-0.46, Cu 0.04-1.58, Fe 0.13-1.63, Mn 0.02-0.12, Mo 5.97-12.46, Pb 0.007-0.074, Sb 0.033-0.088, U 0.5-1.9, V 0.6-2.5 and Zn 0.16-0.80. Concentration ranges (min-max in ng mL -1 ) found in the Venice Lagoon water samples (temporal profile from a benthic chamber experiment) were: Al 0.24-0.61, Ag 0.007-0.031, As 1.42-2.27, Cd 0.050-0.182, Co 0.440-1.461, Cr 0.15-0.34, Cu 0.81-2.46, Fe 0.25-1.66, Mn 11.6-31.7, Mo 6.50-10.6, Pb 0.047-0.225, Sb 0.240-0.492, U 1.7-3.3, V 1.3-2.8 and Zn 5.20-21.5. The detection limits range between 0.06 pg mL -1 for Ag and U to 15 pg mL -1 for Fe. In order to check the accuracy of the analytical procedure, measurements of the trace elements in a certified reference material (coastal Atlantic seawater, CASS-4-NRCC) were compared with the certified values. In addition, the results from the Antarctic and Venice Lagoon samples were compared with those obtained by using different analytical techniques. (orig.)

  6. Elemental ratios for characterization of quantum-dots populations in complex mixtures by asymmetrical flow field-flow fractionation on-line coupled to fluorescence and inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Menendez-Miranda, Mario; Fernandez-Arguelles, Maria T; Costa-Fernandez, Jose M; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo

    2014-08-11

    Separation and identification of nanoparticles of different composition, with similar particle diameter, coexisting in heterogeneous suspensions of polymer-coated CdSe/ZnS quantum dots (QDs) have been thoroughly assessed by asymmetric flow field-flow fractionation (AF4) coupled on-line to fluorescence and inductively coupled plasma mass spectrometry (ICPMS) detectors. Chemical characterization of any previously on-line separated nanosized species was achieved by the measurement of the elemental molar ratios of every element involved in the synthesis of the QDs, using inorganic standards and external calibration by flow injection analysis (FIA). Such elemental molar ratios, strongly limited so far to pure single nanoparticles suspensions, have been achieved with adequate accuracy by coupling for the first time an ICP-QQQ instrument to an AF4 system. This hyphenation turned out to be instrumental to assess the chemical composition of the different populations of nanoparticles coexisting in the relatively complex mixtures, due to its capabilities to detect the hardly detectable elements involved in the synthesis. Interestingly such information, complementary to that obtained by fluorescence, was very valuable to detect and identify unexpected nanosized species, present at significant level, produced during QDs synthesis and hardly detectable by standard approaches. Copyright © 2014. Published by Elsevier B.V.

  7. Trace Element Analysis of Minerals in Magmatic-Hydrothermal Ores by Laser Ablation Inductively-Coupled Plasma Mass Spectrometry: Approaches and Opportunities

    Directory of Open Access Journals (Sweden)

    Nigel Cook

    2016-10-01

    Full Text Available Laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS has rapidly established itself as the method of choice for generation of multi-element datasets for specific minerals, with broad applications in Earth science. Variation in absolute concentrations of different trace elements within common, widely distributed phases, such as pyrite, iron-oxides (magnetite and hematite, and key accessory minerals, such as apatite and titanite, can be particularly valuable for understanding processes of ore formation, and when trace element distributions vary systematically within a mineral system, for a vector approach in mineral exploration. LA-ICP-MS trace element data can assist in element deportment and geometallurgical studies, providing proof of which minerals host key elements of economic relevance, or elements that are deleterious to various metallurgical processes. This contribution reviews recent advances in LA-ICP-MS methodology, reference standards, the application of the method to new mineral matrices, outstanding analytical uncertainties that impact on the quality and usefulness of trace element data, and future applications of the technique. We illustrate how data interpretation is highly dependent on an adequate understanding of prevailing mineral textures, geological history, and in some cases, crystal structure.

  8. Quantitative real-time monitoring of multi-elements in airborne particulates by direct introduction into an inductively coupled plasma mass spectrometer

    International Nuclear Information System (INIS)

    Suzuki, Yoshinari; Sato, Hikaru; Hiyoshi, Katsuhiro; Furuta, Naoki

    2012-01-01

    A new calibration system for real-time determination of trace elements in airborne particulates was developed. Airborne particulates were directly introduced into an inductively coupled plasma mass spectrometer, and the concentrations of 15 trace elements were determined by means of an external calibration method. External standard solutions were nebulized by an ultrasonic nebulizer (USN) coupled with a desolvation system, and the resulting aerosol was introduced into the plasma. The efficiency of sample introduction via the USN was calculated by two methods: (1) the introduction of a Cr standard solution via the USN was compared with introduction of a Cr(CO) 6 standard gas via a standard gas generator and (2) the aerosol generated by the USN was trapped on filters and then analyzed. The Cr introduction efficiencies obtained by the two methods were the same, and the introduction efficiencies of the other elements were equal to the introduction efficiency of Cr. Our results indicated that our calibration method for introduction efficiency worked well for the 15 elements (Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Mo, Sn, Sb, Ba, Tl and Pb). The real-time data and the filter-collection data agreed well for elements with low-melting oxides (V, Co, As, Mo, Sb, Tl, and Pb). In contrast, the real-time data were smaller than the filter-collection data for elements with high-melting oxides (Ti, Cr, Mn, Ni, Cu, Zn, Sn, and Ba). This result implies that the oxides of these 8 elements were not completely fused, vaporized, atomized, and ionized in the initial radiation zone of the inductively coupled plasma. However, quantitative real-time monitoring can be realized after correction for the element recoveries which can be calculated from the ratio of real-time data/filter-collection data. - Highlights: ► APs were directly introduced into ICP-MS and real-time analysis was performed. ► The real-time data were calibrated by a multi-element standard solution from USN. ► During real

  9. Space Station alpha joint bearing

    Science.gov (United States)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  10. Application of neutron activation analysis and inductively coupled plasma mass spectrometry to the determination of toxic and essential elements in Australian foods

    International Nuclear Information System (INIS)

    Fardy, J.J.; McOrist, G.D.; Bowles, C.J.; Farrar, Y.J.; Warner, I.M.

    1990-01-01

    Current Australian legislation specifies the maximum permitted levels of nine toxic elements in foods while the National Health and Medical Research Council (NH and NRC) has listed recommended daily intake figures for seven essential elements. This investigation examined the compliance of Australian foods with both these requirements. Australia-wide samples of representative foods from the diets of Australians were used in this study after the NH and NRC kindly permitted us to join their Market Basket (Noxious Substance) Survey. Both toxic and essential element concentrations in these foods were determined using the advanced analytical techniques of instrumental and radiochemical neutron activation analysis and inductively coupled plasma mass spectrometry. With very few exceptions foods do not exceed the maximum, permitted levels for toxic substances. Daily intake figures for essential elements generally lie close to the maximum recommended values listed by NH and NRC. (author). 11 refs, 22 figs, 17 tabs

  11. Bearing assemblies, apparatuses, and motor assemblies using the same

    Science.gov (United States)

    Sexton, Timothy N.; Cooley, Craig H.; Knuteson, Cody W.

    2015-12-29

    Various embodiments of the invention relate to bearing assemblies, apparatuses and motor assemblies that include geometric features configured to impart a selected amount of heat transfer and/or hydrodynamic film formation. In an embodiment, a bearing assembly may include a plurality of superhard bearing pads distributed circumferentially about an axis. At least some of the plurality of superhard bearing pads may include a plurality of sub-superhard bearing elements defining a bearing surface. At least some of the plurality of sub-superhard bearing elements may be spaced from one another by one or more voids to impart a selected amount of heat transfer and hydrodynamic film formation thereon during operation. The bearing assembly may also include a support ring that carries the plurality of superhard bearing pads. In addition, at least a portion of the sub-superhard bearing elements may extend beyond the support ring.

  12. Bearing structures

    International Nuclear Information System (INIS)

    Lee, A.S.; Preece, G.E.

    1988-01-01

    A hydrostatic bearing for the lower end of the vertical shaft of a sodium pump comprises a support shell encircling the shaft and a bush located between the shell and shaft. Liquid sodium is fed from the pump outlet to the bush/shaft and bush/shell interfaces to provide hydrostatic support. The bush outer surface and the shell inner surface are of complementary part-spherical shape and the bush floats relative to the shaft so that the bush can align itself with the shaft axis. Monitoring of the relative rotational speed of the bush with respect to the shaft (such rotation being induced by the viscous drag forces present) is also performed for the purposes of detecting abnormal operation of the bearing or partial seizure, at least one magnet is rotatable with the bush, and a magnetic sensor provides an output having a frequency related to the speed of the bush. (author)

  13. Journal Bearings

    Directory of Open Access Journals (Sweden)

    Renato Brancati

    1999-01-01

    determined after acquiring and analysing the orbits described by the journal axis for assigned unbalance values in different operating conditions. Analysis of the results shows some particular operating features that were not entirely predicted by the theoretical model and which may give rise to malfunctions in the rotor-tilting pad bearings system. The tests were carried out in the rotor dynamics laboratory of the Dipartimento di Ingegneria Meccanica per l'Energetica at the University of Naples.

  14. Camshaft bearing arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Aoi, K.; Ozawa, T.

    1986-06-10

    A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

  15. Quantification of trace amounts of rare earth elements in high purity gadolinium oxide by sector field inductively coupled plasma mass spectrometry (ICP-MS)

    International Nuclear Information System (INIS)

    Pedreira, W.R.; Silva Queiroz, C.A. da; Abrao, A.; Pimentel, M.M.

    2004-01-01

    In recent years, rare earth elements (REEs) have received much attention in the fields of geochemistry and industry. Gadolinium oxide is used for many different high technology applications such as infrared absorbing automotive glass, petroleum cracking catalyst, gadolinium-yttrium garnets, microwave applications, and color TV tube phosphors. It can also be used in optical glass manufacturing and in the electronic industry. Rapid and accurate determinations of the rare earth elements are increasingly required as industrial demands expand. In general, the inductively coupled plasma mass spectrometry (ICP-MS) presents some advantages for trace element analysis, due to high sensitivity and resolution, when compared with other analytical techniques. In this work, sector field inductively coupled plasma mass spectrometry was used. Sixteen elements (Sc, Y, and 14 lanthanides) were determined selectively with the ICP-MS system using a concentration gradient method. The detection limits with the ICP-MS system were about 0.2-8 pg ml -1 . The recovery percentage ranged from 95 to 100% for different rare earth elements. The %R.S.D. of the methods varying between 1.5 and 2.5% for a set of five (n=5) replicates was found for the IPEN's material and for the certificate reference sample. Determination of trace REEs in two high pure gadolinium oxides samples (IPEN and JMC) was performed. IPEN's material is highly pure (>99.99%) and was successfully analyzed without spectral interference

  16. Direct determination of trace rare earth elements in ancient porcelain samples with slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Xiang Guoqiang; Jiang Zucheng; He Man; Hu Bin

    2005-01-01

    A method for the direct determination of trace rare earth elements in ancient porcelain samples by slurry sampling fluorinating electrothermal vaporization inductively coupled plasma mass spectrometry was developed with the use of polytetrafluoroethylene as fluorinating reagent. It was found that Si, as a main matrix element in ancient porcelain sample, could be mostly removed at the ashing temperature of 1200 deg. C without considerable losses of the analytes. However, the chemical composition of ancient porcelain sample is very complicated, which makes the influences resulting from other matrix elements not be ignored. Therefore, the matrix effect of ancient porcelain sample was also investigated, and it was found that the matrix effect is obvious when the matrix concentration was larger than 0.8 g l -1 . The study results of particle size effect indicated that when the sample particle size was less than 0.057 mm, the particle size effect is negligible. Under the optimized operation conditions, the detection limits for rare earth elements by fluorinating electrothermal vaporization inductively coupled plasma mass spectrometry were 0.7 ng g -1 (Eu)-33.3 ng g -1 (Nd) with the precisions of 4.1% (Yb)-10% (La) (c = 1 μg l -1 , n = 9). The proposed method was used to directly determine the trace rare earth elements in ancient porcelain samples produced in different dynasty (Sui, Ming and Qing), and the analytical results are satisfactory

  17. Determination of rare-earth elements, yttrium and scandium in manganese nodules by inductively-coupled argon-plastma emission spectrometry

    Science.gov (United States)

    Fries, T.; Lamothe, P.J.; Pesek, J.J.

    1984-01-01

    A sequential-scanning, inductively-coupled argon plasma emission spectrometer is used for the determination of the rare-earth elements, plus yttrium and scandium, in manganese nodules. Wavelength selection is optimized to minimize spectral interferences from manganese nodule components. Samples are decomposed with mixed acids in a sealed polycarbonate vessel, and elements are quantified without further treatment. Results for U.S. Geological Survey manganese nodule standards A-1 and P-1 had average relative standard deviations of 6.8% and 8.1%, respectively, and results were in good agreement with those obtained by other methods. ?? 1984.

  18. Analysis of Rare Earth Elements in Geologic Samples using Inductively Coupled Plasma Mass Spectrometry; US DOE Topical Report - DOE/NETL-2016/1794

    Energy Technology Data Exchange (ETDEWEB)

    Bank, Tracy L. [AECOM, Pittsburgh, PA (United States); Roth, Elliot A. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Tinker, Phillip [AECOM, Pittsburgh, PA (United States); Granite, Evan [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2016-04-17

    Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is used to measure the concentrations of rare earth elements (REE) in certified standard reference materials including shale and coal. The instrument used in this study is a Perkin Elmer Nexion 300D ICP-MS. The goal of the study is to identify sample preparation and operating conditions that optimized recovery of each element of concern. Additionally, the precision and accuracy of the technique are summarized and the drawbacks and limitations of the method are outlined.

  19. Resilient and Corrosion-proof Rolling Element Bearings Made from Ni-ti Alloys for Aerospace Mechanism Applications and the Ultimate Space Technology Development Platform

    Science.gov (United States)

    Dellacorte, Christopher

    2014-01-01

    The International Space Station provides a unique microgravity laboratory environment for research. The ISS also serves as an effective platform for the development of technologies and engineered solutions related to living and working in space. The space environment also challenges our capabilities related to lubrication and tribology. In this seminar, Dr. DellaCorte will review the basics of space mechanism tribology and the challenges of providing good lubrication and long-life in the harsh space environment. He will also discuss recent tribological challenges associated with the Solar Alpha Rotary Joint (SARJ) bearings and life support hardware that must operate under severe conditions that are literally out of this world. Each tribology challenge is unique and their solutions often result in new technologies that benefit the tribology community everywhere, even back on Earth

  20. Development of the dorsal circumorbital bones in the leopard gecko (Eublepharis macularius) and its bearing on the homology of these elements in the gekkota.

    Science.gov (United States)

    Wise, Patrick Arthur David; Russell, Anthony Patrick

    2010-12-01

    Five nominal elements comprise the circumorbital series of bones in gekkotans: prefrontal, postfrontal, postorbital, jugal, and lacrimal. Determination of the homology of two of these, the postfrontal and postorbital, has been particularly problematic. Two conflicting hypothesis exist relating to these: either the postorbital is lost and the postfrontal remains or they fuse during development to form a combined element, the postorbitofrontal. Such a combined element apparently occurs in at least some members of all lizard clades. There is, however, no direct developmental evidence that supports either theory. To overcome that, we investigate the sequence and pattern of ossification in the circumorbital region in a developmental series of the Leopard gecko. We posit that both the postfrontal and postorbital appear during development. Contrary to previous predictions they neither fuses to each other, nor do either degenerate. Instead, the postfrontal shifts anteriorly and fuses with the frontal to become indistinguishable from it by the time of hatching, and the postorbital persists as a robust independent element bounding the frontoparietal suture. These observations accord, in part, with both hypotheses of homology of these elements and result in the recognition of a new pattern, placing in doubt the existence of the composite postorbitofrontal. The phylogenetic implications of these findings may prove to be far reaching if similar and conserved patterns of development are encountered in other clades.

  1. Synthesis of 2'-deoxyadenosine nucleosides bearing bipyridine-type ligands and their Ru-complexes in position 8 through cross-coupling reactions

    Czech Academy of Sciences Publication Activity Database

    Vrábel, Milan; Pohl, Radek; Klepetářová, Blanka; Votruba, Ivan; Hocek, Michal

    2007-01-01

    Roč. 5, č. 17 (2007), s. 2849-2857 ISSN 1477-0520 R&D Projects: GA MŠk LC512; GA ČR GA203/05/0043 Institutional research plan: CEZ:AV0Z40550506 Keywords : nucleosides * purines * cross-coupling * ruthenium Subject RIV: CC - Organic Chemistry Impact factor: 3.167, year: 2007

  2. Modeling of fluid injection and withdrawal induced fault activation using discrete element based hydro-mechanical and dynamic coupled simulator

    Science.gov (United States)

    Yoon, Jeoung Seok; Zang, Arno; Zimmermann, Günter; Stephansson, Ove

    2016-04-01

    Operation of fluid injection into and withdrawal from the subsurface for various purposes has been known to induce earthquakes. Such operations include hydraulic fracturing for shale gas extraction, hydraulic stimulation for Enhanced Geothermal System development and waste water disposal. Among these, several damaging earthquakes have been reported in the USA in particular in the areas of high-rate massive amount of wastewater injection [1] mostly with natural fault systems. Oil and gas production have been known to induce earthquake where pore fluid pressure decreases in some cases by several tens of Mega Pascal. One recent seismic event occurred in November 2013 near Azle, Texas where a series of earthquakes began along a mapped ancient fault system [2]. It was studied that a combination of brine production and waste water injection near the fault generated subsurface pressures sufficient to induced earthquakes on near-critically stressed faults. This numerical study aims at investigating the occurrence mechanisms of such earthquakes induced by fluid injection [3] and withdrawal by using hydro-geomechanical coupled dynamic simulator (Itasca's Particle Flow Code 2D). Generic models are setup to investigate the sensitivity of several parameters which include fault orientation, frictional properties, distance from the injection well to the fault, amount of fluid withdrawal around the injection well, to the response of the fault systems and the activation magnitude. Fault slip movement over time in relation to the diffusion of pore pressure is analyzed in detail. Moreover, correlations between the spatial distribution of pore pressure change and the locations of induced seismic events and fault slip rate are investigated. References [1] Keranen KM, Weingarten M, Albers GA, Bekins BA, Ge S, 2014. Sharp increase in central Oklahoma seismicity since 2008 induced by massive wastewater injection, Science 345, 448, DOI: 10.1126/science.1255802. [2] Hornbach MJ, DeShon HR

  3. Geochemical correlations between uranium and other components in U-bearing formations of Ogcheon belt

    International Nuclear Information System (INIS)

    Lee, M.S.; Chon, H.T.

    1980-01-01

    Some components in uranium-bearing formations which consist mainly of black shale, slate and low grade coal-bearing formation of Ogcheon Belt were processed statistically in order to find out the geochemical correlations with uranium. Geochemical enrichment of uranium, vanadium and molybdenum in low grade coal-bearing formations and surrounding rocks is remarkable in the studied area. Geochemical correlation coefficient of uranium and molybdenum in the rocks displays about 0.6 and that of uranium and fixed carbon about 0.4. Uranium and vanadium in uranium-bearing low grade coals denote very high correlation with fixed carbon, which is considered to be responsible for enrichment of metallic elements, especially molybdenum. Close geochemical correlation of uranium-molybdenum couple in the rocks can be applied as a competent exploration guide to low grade uranium deposits of this area. (author)

  4. Laser ablation ICPMS study of trace element chemistry in molybdenite coupled with scanning electron microscopy (SEM) - An important tool for identification of different types of mineralization

    Czech Academy of Sciences Publication Activity Database

    Pašava, J.; Svojtka, Martin; Veselovský, F.; Ďurišová, Jana; Ackerman, Lukáš; Pour, O.; Drábek, M.; Halodová, P.; Haluzová, Eva

    2016-01-01

    Roč. 72, č. 1 (2016), s. 874-895 ISSN 0169-1368 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : molybdenite * trace-element geochemistry * Laser Ablation Inductively Coupled Mass * spectrometry * scanning electron microscopy * nano- to micro-inclusions * Bohemian Massif * Uzbekistan Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.095, year: 2016

  5. Application of neutron activation analysis and inductively coupled plasma mass spectrometry to the determination of toxic and essential elements in Australian foods

    International Nuclear Information System (INIS)

    Fardy, J.J.; McOrist, G.D.; Farrar, Y.J.; Bowles, C.J.; Warner, I.M.; Tan Mingguang

    1994-01-01

    Current Australian Legislation specifies the maximum permitted levels of nine toxic elements in food while the National Health and Medical Research Council (NH and MRC) has listed recommended daily intake figures for seven essential elements. This investigation examined the compliance of Australian foods with both these requirements. Australia-wide samples of representative foods from the diets of Australians were used in this study after the NH and MRC kindly permitted us to join their Market Basket (Noxious Substance) Survey. Both toxic and essential element concentrations in these foods were determined using the advanced analytical techniques of instrumental (INAA) and radiochemical neutron activation analysis (RNAA) and inductively coupled plasma mass spectrometry (ICP-MS). With very few exceptions, foods do not exceed the maximum permitted levels for toxic substances. Daily intake figures for essential elements generally lie close to the maximum recommended values listed by NH and MRC. Since another source of toxic element intake is drinking water, samples from different locations were analyzed by NAA and inductively coupled plasma atomic emission spectroscopy (ICP-AES). They were extremely low in trace elements with the exception of copper, iron, zinc and lead which approached the maximum permitted concentrations. The performance of NAA and ICP-MS for analyzing biological materials were compared. NAA cannot match the superior sensitivity for a wider range of elements obtained by ICP-MS. This has been verified for a wide range of food materials. While NAA is an inconvenient and time-consuming technique for many applications, it does not suffer from blank problems after irradiation of the sample and becomes the preferred technique where low limits of detection are required for trace concentrations in solid samples. (author). 22 refs, 27 figs, 21 tabs

  6. Enhanced susceptibility of a transposable-element-bearing strain of Drosophila melanogaster to somatic eye-color mutations by ethyl nitrosourea, methyl nitrosourea, and X-rays

    International Nuclear Information System (INIS)

    Ryo, H.; Kondo, S.; Rasmuson, B.

    1983-01-01

    A strain of Drosophila with the genes z and w + plus a transposable element (TE) is about 3 times more sensitive than a strain without TE toward somatic eye-color mutations after larval exposure to ethyl nitrosourea, methyl nitrosourea and X-rays. The assay system with TE is simple, reliable, and sensitive for detecting somatic mutations induced in vivo by mutagens. (orig.)

  7. Development of finite element code for the analysis of coupled thermo-hydro-mechanical behaviors of a saturated-unsaturated medium

    International Nuclear Information System (INIS)

    Ohnishi, Y.; Shibata, H.; Kobsayashi, A.

    1987-01-01

    A model is presented which describes fully coupled thermo-hydro-mechanical behavior of a porous geologic medium. The mathematical formulation for the model utilizes the Biot theory for the consolidation and the energy balance equation. If the medium is in the condition of saturated-unsaturated flow, then the free surfaces are taken into consideration in the model. The model, incorporated in a finite element numerical procedure, was implemented in a two-dimensional computer code. The code was developed under the assumptions that the medium is poro-elastic and in the plane strain condition; that water in the ground does not change its phase; and that heat is transferred by conductive and convective flow. Analytical solutions pertaining to consolidation theory for soils and rocks, thermoelasticity for solids and hydrothermal convection theory provided verification of stress and fluid flow couplings, respectively, in the coupled model. Several types of problems are analyzed

  8. The use of cation exchange matrix separation coupled with ICP-MS to directly determine platinum group element (PGE) and other trace element emissions from passenger cars equipped with diesel particulate filters (DPF)

    Energy Technology Data Exchange (ETDEWEB)

    Cairns, Warren R.L.; Cozzi, Giulio [Institute for the Dynamics of Environmental Processes-CNR, Venice (Italy); De Boni, Antonella; Gabrieli, Jacopo [University of Venice, Department of Environmental Science, Venice (Italy); Asti, Massimo; Merlone Borla, Edoardo; Parussa, Flavio [Centro Ricerche Fiat, Orbassano (Italy); Moretto, Ezio [FIAT Powertrain Technologies S.p.A, Turin (Italy); Cescon, Paolo; Barbante, Carlo [University of Venice, Department of Environmental Science, Venice (Italy); Institute for the Dynamics of Environmental Processes-CNR, Venice (Italy); Boutron, Claude [Laboratoire de Glaciologie et Geophysique de l' Environnement, UMR CNRS 5183, B.P. 96, Saint Martin d' Heres Cedex (France)

    2011-03-15

    Inductively coupled plasma-mass spectrometry coupled with cation exchange matrix separation has been optimised for the direct determination of platinum group element (PGE) and trace element emissions from a diesel engine car. After matrix separation method detection limits of 1.6 ng g{sup -1} for Pd, 0.4 ng g{sup -1} for Rh and 4.3 ng g{sup -1} for Pt were achieved, the method was validated against the certified reference material BCR 723, urban road dust. The test vehicle was fitted with new and aged catalytic converters with and without diesel particulate filters (DPF). Samples were collected after three consecutive New European Driving Cycle (NEDC) of the particulate and ''soluble'' phases using a home-made sampler optimised for trace element analysis. Emission factors for the PGEs ranged from 0.021 ng km{sup -1} for Rh to 70.5 ng km{sup -1} for Pt; when a DPF was fitted, the emission factors for the PGEs actually used in the catalysts dropped by up to 97% (for Pt). Trace element emission factors were found to drop by a maximum of 92% for Ni to a minimum of 18% for Y when a DPF was fitted; a new DPF was also found to cause a reduction of up to 86% in the emission of particulate matter. (orig.)

  9. Micromagnetic finite element study for magnetic properties of nanocomposite exchange coupled Nd{sub 2}Fe{sub 14}B/α-Fe multilayer systems

    Energy Technology Data Exchange (ETDEWEB)

    Ryo, Hyok-Su [School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Faculty of Physics, Kim Il Sung University, Pyongyang 999093, Democratic People’s Republic of Korea (Korea, Republic of); Hu, Lian-Xi [School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Kim, Jin-Guk [School of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Faculty of Physics, Kim Il Sung University, Pyongyang 999093, Democratic People’s Republic of Korea (Korea, Republic of); Yang, Yu-Lin [School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2017-03-15

    In this study, magnetic properties of exchange coupled nanocomposite multilayer thin films constructed alternately with magnetic hard Nd{sub 2}Fe{sub 14}B layers and soft α-Fe layers have been studied by micromagnetic finite element method (FEM). According to the results, effects of the thicknesses of layers and the magneto-crystalline anisotropy on the magnetic properties of the Nd{sub 2}Fe{sub 14}B/α-Fe multilayer systems have been estimated. On the other hand, the results have been analyzed by means of efficiency of interphase exchange coupling, which can be estimated by volume ratios of exchange coupled areas between magnetically hard Nd{sub 2}Fe{sub 14}B and soft α-Fe phase layers. The results show that the magnetic properties of exchange coupled Nd{sub 2}Fe{sub 14}B/α-Fe multilayer systems can be enhanced by efficient interphase exchange coupling between magnetically hard Nd{sub 2}Fe{sub 14}B layers and soft α-Fe layers. - Highlights: • Phase layer thicknesses dependence of magnetic properties of Nd{sub 2}Fe{sub 14}B/α-Fe multilayers. • Analyzation of the effectiveness of exchange coupling between the Nd{sub 2}Fe{sub 14}B and α-Fe layers. • Dependence of the magnetic properties on direction of external field of exchange coupled Nd{sub 2}Fe{sub 14}B/α-Fe multilayers. • Dependence of the magnetic properties on magneto-crystalline anisotropy of exchange coupled Nd{sub 2}Fe{sub 14}B/α-Fe multilayers.

  10. Journal and Wave Bearing Impedance Calculation Software

    Science.gov (United States)

    Hanford, Amanda; Campbell, Robert

    2012-01-01

    The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

  11. Improving the performance of finite element simulations on the wheel–rail interaction by using a coupling strategy

    NARCIS (Netherlands)

    Ma, Y.; Markine, V.L.; Ahad Mashal, Abdul; Ren, Mingfa

    2018-01-01

    Over the past few years, a number of implicit/explicit finite element models have been introduced for the purpose of tackling the problems of wheel–rail interaction. Yet, most of those finite element models encounter common numerical difficulties. For instance, initial gaps/penetrations between two

  12. Leaching Process of Rare Earth Elements, Gallium and Niobium in a Coal-Bearing Strata-Hosted Rare Metal Deposit—A Case Study from the Late Permian Tuff in the Zhongliangshan Mine, Chongqing

    Directory of Open Access Journals (Sweden)

    Jianhua Zou

    2017-05-01

    Full Text Available The tuff, a part of coal-bearing strata, in the Zhongliangshan coal mine, Chongqing, southwestern China, hosts a rare metal deposit enriched in rare earth elements (REE, Ga and Nb. However, the extraction techniques directly related to the recovery of rare metals in coal-bearing strata have been little-studied in the literature. The purpose of this paper is to investigate the extractability of REE, Ga and Nb in the tuff in the Zhongliangshan mine using the alkaline sintering-water immersion-acid leaching (ASWIAL method. The results show that ASWIAL can separate and extract REE, Ga and Nb effectively under the optimized conditions of calcining at 860 °C for 0.5 h with a sample to sintering agent ratio of 1:1.5, immersing at 90 °C for 2 h with 150 mL hot water dosage, and leaching using 4 mol/L HCl at 40 °C for 2 h with a liquid-solid ratio of 20:1 (mL:g. The final leaching efficiencies of REE and Ga are up to 85.81% and 93.37%, respectively, whereas the leaching efficiency of Nb is less than 1%, suggesting the high concentration of Nb in the leaching residue, which needs further extraction.

  13. Imaging of elements in leaves of tobacco by solid sampling–electrothermal vaporization–inductively coupled plasma-optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Masson, Pierre, E-mail: masson@bordeaux.inra.fr

    2014-12-01

    Plants take up and store elements according to the environment in which they are growing. Because plants are at the base of the food chain, the determination of essential elements or toxic elements in plant materials is of importance. However, it is assumed that the element content determined on selected tissues may provide more specific information than that derived from the whole plant analysis. In this work, we assessed the feasibility of solid sampling–electrothermal vaporization–inductively coupled plasma-optical emission spectrometry analyses for quantitative imaging of Cd and Mg in plant leaves. Leaves of tobacco (Nicotiana tabacum) were selected to be used as samples. To produce a two dimensional image, sections cut from leaf samples were analyzed. Cellulose doped with multi-element solution standards was used as calibration samples. Two certified reference materials (NIST SRM 1547 Peach Leaves and NIST SRM 1573a Tomato leaves) were used to verify the accuracy of measurements with good agreement between the measured concentrations and the certified values. Quantitative imaging revealed the inhomogeneous distribution of the selected elements. Excess of Cd and Mg tended to be focused on peripheral regions and the tip of the leaf.

  14. The matrix effect of biological concomitant element on the signal intensity of Ge, As, and Se in inductively coupled plasma/mass spectrometry

    International Nuclear Information System (INIS)

    Park, Kyung Su; Kim, Sun Tae; Kim, Young Man; Kim, Yun Je; Lee, Won

    2002-01-01

    The non-spectroscopic interference effects that occurred in inductively coupled plasma/mass spectrometry were studied for Ge, As and Se in human urine and serum. Many biological samples contain Na, K, Cl and organic compounds, which may cause the enhancement and depression on the analyte signal. The effect of 1% concomitant elements such as N, Cl, S, P, C, Na, and K on a 100 μg/L germanium, arsenic and selenium signal has been investigated by ICP/MS. The interference effects were not in the same direction. It appeared that concomitant elements such as Cl, S and C induce an enhancement effect, whereas N and P did not show any significant effect. And, Na and K caused a depression . We have found a link between the abundance of analytes and the ionization potential of concomitant elements (eV), except carbon and nitrogen

  15. A finite element method for the numerical solution of the coupled Cahn-Hilliard and Navier-Stokes system for moving contact line problems

    KAUST Repository

    Bao, Kai

    2012-10-01

    In this paper, a semi-implicit finite element method is presented for the coupled Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition for the moving contact line problems. In our method, the system is solved in a decoupled way. For the Cahn-Hilliard equations, a convex splitting scheme is used along with a P1-P1 finite element discretization. The scheme is unconditionally stable. A linearized semi-implicit P2-P0 mixed finite element method is employed to solve the Navier-Stokes equations. With our method, the generalized Navier boundary condition is extended to handle the moving contact line problems with complex boundary in a very natural way. The efficiency and capacity of the present method are well demonstrated with several numerical examples. © 2012 Elsevier Inc..

  16. Inductively coupled plasma-mass spectrometry for elemental analysis and isotope ratio determinations in individual organic compounds separated by gas chromatography

    International Nuclear Information System (INIS)

    Chong, N.S.; Houk, R.S.

    1987-01-01

    A gas chromatograph (GC) with a packed column was interfaced to an inductively coupled plasma-mass spectrometer (ICP-MS) to yield atomic mass spectra from volatile organic compounds. Atomization of injected compounds was nearly complete and independent of molecular structure, so that elemental ratios could be determined. Detection limits were in the range 0.001 to 400 ng s -1 , depending on the ionization energy of the element and its abundance in the background spectrum. The relative standard deviation of measured isotope ratios varied from 0.4% for Br (i.e., a ratio close to unity) to 18% for N (a very large ratio). Thus, GC-ICP-MS provides elemental and isotope ratio information that is complementary to the molecular information derived from GC-MS with conventional ionization methods

  17. A finite element method for the numerical solution of the coupled Cahn-Hilliard and Navier-Stokes system for moving contact line problems

    KAUST Repository

    Bao, Kai; Shi, Yi; Sun, Shuyu; Wang, Xiaoping

    2012-01-01

    In this paper, a semi-implicit finite element method is presented for the coupled Cahn-Hilliard and Navier-Stokes equations with the generalized Navier boundary condition for the moving contact line problems. In our method, the system is solved in a decoupled way. For the Cahn-Hilliard equations, a convex splitting scheme is used along with a P1-P1 finite element discretization. The scheme is unconditionally stable. A linearized semi-implicit P2-P0 mixed finite element method is employed to solve the Navier-Stokes equations. With our method, the generalized Navier boundary condition is extended to handle the moving contact line problems with complex boundary in a very natural way. The efficiency and capacity of the present method are well demonstrated with several numerical examples. © 2012 Elsevier Inc..

  18. Are PEEK-on-Ceramic Bearings an Option for Total Disc Arthroplasty? An In Vitro Tribology Study.

    Science.gov (United States)

    Siskey, Ryan; Ciccarelli, Lauren; Lui, Melissa K C; Kurtz, Steven M

    2016-11-01

    Most contemporary total disc replacements (TDRs) use conventional orthopaedic bearing couples such as ultrahigh-molecular-weight polyethylene (polyethylene) and cobalt-chromium (CoCr). Cervical total disc replacements incorporating polyetheretherketone (PEEK) bearings (specifically PEEK-on-PEEK bearings) have been previously investigated, but little is known about PEEK-on-ceramic bearings for TDR. (1) What is the tribologic behavior of a PEEK-on-ceramic bearing for cervical TDR under idealized, clean wear test conditions? (2) How does the PEEK-on-ceramic design perform under impingement conditions? (3) How is the PEEK-on-ceramic bearing affected by abrasive wear? (4) Is the particle morphology from PEEK-on-ceramic bearings for TDRs affected by adverse wear scenarios? PEEK-on-ceramic cervical TDR bearings were subjected to a 10 million cycle ideal wear test based on ASTM F2423 and ISO 181912-1 using a six-station spine wear simulator (MTS, Eden Prairie, MN, USA) with 5 g/L bovine serum concentration at 23° ± 2° C (ambient temperature). Validated 1 million cycle impingement and 5 million cycle abrasive tests were conducted on the PEEK-on-ceramic bearings based, in part, on retrieval analysis of a comparable bearing design as well as finite element analyses. The ceramic-on-PEEK couple was characterized for damage modes, mass and volume loss, and penetration and the lubricant was subjected to particle analysis. The resulting mass wear rate, volumetric wear rate, based on material density, and particle analysis were compared with clinically available cervical disc bearing couples. The three modes of wear (idealized, impingement, and abrasive) resulted in mean mass wear rates of 0.9 ± 0.2 mg/MC, 1.9 ± 0.5 mg/MC, and 2.8 ± 0.6 mg/MC, respectively. The mass wear rates were converted to volumetric wear rates using density and found to be 0.7 ± 0.1 mm 3 /MC, 1.5 ± 0.4 mm 3 /MC, and 2.1 ± 0.5 mm 3 /MC, respectively. During each test, the PEEK

  19. Bk and Cf chromatographic separation and 249Bk/248Cm and 249Cf/248Cm elemental ratios determination by inductively coupled plasma quadrupole mass spectrometry

    International Nuclear Information System (INIS)

    Gourgiotis, A.; Isnard, H.; Nonell, A.; Aubert, M.; Stadelmann, G.; Dupont, E.; AlMahamid, I.; Tiang, G.; Rao, L.; Lukens, W.; Cassette, P.; Panebianco, S.; Letourneau, A.; Chartier, F.

    2013-01-01

    The French Atomic Energy Commission has carried out several experiments for the study of minor-actinide transmutation processes in high intensity thermal neutron flux. In this context a Cm sample enriched in 248 Cm (97%) was irradiated in a thermal neutron flux at the High Flux Reactor (HFR) of the Laue-Langevin Institute (ILL). The precise and accurate determination of Cf isotope ratios and of 249 Bk/ 248 Cm and 249 Cf/ 248 Cm elemental ratios in the 248 Cm irradiated sample is crucial for the calculation of actinide neutron capture cross-sections.This work describes an analytical procedure for the separation and the isotope ratio measurement of Bk and Cf in the irradiated sample.The Bk and Cf separation is based on a lanthanides separation protocol previously developed by the laboratory. Well-defined retention times for Bk and Cf were obtained by coupling the Ionic Chromatography (IC) with an ICP-QMS. All conditions of element separation by IC and the different steps of the analytical protocol in order to obtain the isotopic and elemental ratios are presented. Relative uncertainties of Cf isotopic ratios range from 0.3% to 0.5% and the uncertainty of the 249 Bk/ 248 Cm and 249 Cf/ 248 Cm elemental ratios are respectively 6.1% and 3.2%.This level of uncertainty for both isotopic and elemental ratios is in perfect agreement with the requirement for transmutation studies. (authors)

  20. Carbon-Phenolic Cages for High-Speed Bearings. Part III - Development of Numerical Models for Heat Generation and Temperature Prediction in Lightly Lubricated Bearings

    National Research Council Canada - National Science Library

    Brown, Jeffrey

    2003-01-01

    .... This portion describes the bearing and thermal analysis models. A process has been developed to numerically investigate operating temperatures of a rolling element bearing which combines capabilities of the Advanced Dynamics of Rolling Elements (ADORE...

  1. Identification of Bearing Failure Using Signal Vibrations

    Science.gov (United States)

    Yani, Irsyadi; Resti, Yulia; Burlian, Firmansyah

    2018-04-01

    Vibration analysis can be used to identify damage to mechanical systems such as journal bearings. Identification of failure can be done by observing the resulting vibration spectrum by measuring the vibration signal occurring in a mechanical system Bearing is one of the engine elements commonly used in mechanical systems. The main purpose of this research is to monitor the bearing condition and to identify bearing failure on a mechanical system by observing the resulting vibration. Data collection techniques based on recordings of sound caused by the vibration of the mechanical system were used in this study, then created a database system based bearing failure due to vibration signal recording sounds on a mechanical system The next step is to group the bearing damage by type based on the databases obtained. The results show the percentage of success in identifying bearing damage is 98 %.

  2. Investigation of Drag Force on Fibres of Bonded Spherical Elements using a Coupled CFD-DEM Approach

    DEFF Research Database (Denmark)

    Jensen, Anna Lyhne; Sørensen, Henrik; Rosendahl, Lasse Aistrup

    2016-01-01

    Clogging in wastewater pumps is often caused by flexible, stringy objects. Therefore, simulation of clogging effects in wastewater pumps entails simulation of such flexible objects and the interaction between these objects and fluid in the pump. Using a coupled CFD-DEM approach, the flexible obje...

  3. Sampling strategy and analysis of trace element concentrations by inductively coupled plasma mass spectrometry on medieval human bones--the concept of chemical life history.

    Science.gov (United States)

    Skytte, Lilian; Rasmussen, Kaare Lund

    2013-07-30

    Medieval human bones have the potential to reveal diet, mobility and treatment of diseases in the past. During the last two decades trace element chemistry has been used extensively in archaeometric investigations revealing such data. Many studies have reported the trace element inventory in only one sample from each skeleton - usually from the femur or a tooth. It cannot a priori be assumed that all bones or teeth in a skeleton will have the same trace element concentrations. Six different bone and teeth samples from each individual were carefully decontaminated by mechanical means. Following dissolution of ca. 20 mg sample in nitric acid and hydrogen peroxide the assays were performed using inductively coupled plasma mass spectrometry (ICPMS) with quadropole detection. We describe the precise sampling technique as well as the analytical methods and parameters used for the ICPMS analysis. The places of sampling in the human skeleton did exhibit varying trace element concentrations. Although the samples are contaminated by Fe, Mn and Al from the surrounding soil where the bones have been residing for more than 500 years, other trace elements are intact within the bones. It is shown that the elemental ratios Sr/Ca and Ba/Ca can be used as indicators of provenance. The differences in trace element concentrations can be interpreted as indications of varying diet and provenance as a function of time in the life of the individual - a concept which can be termed chemical life history. A few examples of the results of such analyses are shown, which contains information about provenance and diagenesis. Copyright © 2013 John Wiley & Sons, Ltd.

  4. Application of a microwave-based desolvation system for multi-elemental analysis of wine by inductively coupled plasma based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Grindlay, Guillermo [Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, P.O. Box 99, 03080 Alicante (Spain)], E-mail: guillermo.grindlay@ua.es; Mora, Juan; Maestre, Salvador; Gras, Luis [Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, P.O. Box 99, 03080 Alicante (Spain)

    2008-11-23

    Elemental wine analysis is often required from a nutritional, toxicological, origin and authenticity point of view. Inductively coupled plasma based techniques are usually employed for this analysis because of their multi-elemental capabilities and good limits of detection. However, the accurate analysis of wine samples strongly depends on their matrix composition (i.e. salts, ethanol, organic acids) since they lead to both spectral and non-spectral interferences. To mitigate ethanol (up to 10% w/w) related matrix effects in inductively coupled plasma atomic emission spectrometry (ICP-AES), a microwave-based desolvation system (MWDS) can be successfully employed. This finding suggests that the MWDS could be employed for elemental wine analysis. The goal of this work is to evaluate the applicability of the MWDS for elemental wine analysis in ICP-AES and inductively coupled plasma mass spectrometry (ICP-MS). For the sake of comparison a conventional sample introduction system (i.e. pneumatic nebulizer attached to a spray chamber) was employed. Matrix effects, precision, accuracy and analysis throughput have been selected as comparison criteria. For ICP-AES measurements, wine samples can be directly analyzed without any sample treatment (i.e. sample dilution or digestion) using pure aqueous standards although internal standardization (IS) (i.e. Sc) is required. The behaviour of the MWDS operating with organic solutions in ICP-MS has been characterized for the first time. In this technique the MWDS has shown its efficiency to mitigate ethanol related matrix effects up to concentrations of 1% (w/w). Therefore, wine samples must be diluted to reduce the ethanol concentration up to this value. The results obtained have shown that the MWDS is a powerful device for the elemental analysis of wine samples in both ICP-AES and ICP-MS. In general, the MWDS has some attractive advantages for elemental wine analysis when compared to a conventional sample introduction system such

  5. Application of a microwave-based desolvation system for multi-elemental analysis of wine by inductively coupled plasma based techniques

    International Nuclear Information System (INIS)

    Grindlay, Guillermo; Mora, Juan; Maestre, Salvador; Gras, Luis

    2008-01-01

    Elemental wine analysis is often required from a nutritional, toxicological, origin and authenticity point of view. Inductively coupled plasma based techniques are usually employed for this analysis because of their multi-elemental capabilities and good limits of detection. However, the accurate analysis of wine samples strongly depends on their matrix composition (i.e. salts, ethanol, organic acids) since they lead to both spectral and non-spectral interferences. To mitigate ethanol (up to 10% w/w) related matrix effects in inductively coupled plasma atomic emission spectrometry (ICP-AES), a microwave-based desolvation system (MWDS) can be successfully employed. This finding suggests that the MWDS could be employed for elemental wine analysis. The goal of this work is to evaluate the applicability of the MWDS for elemental wine analysis in ICP-AES and inductively coupled plasma mass spectrometry (ICP-MS). For the sake of comparison a conventional sample introduction system (i.e. pneumatic nebulizer attached to a spray chamber) was employed. Matrix effects, precision, accuracy and analysis throughput have been selected as comparison criteria. For ICP-AES measurements, wine samples can be directly analyzed without any sample treatment (i.e. sample dilution or digestion) using pure aqueous standards although internal standardization (IS) (i.e. Sc) is required. The behaviour of the MWDS operating with organic solutions in ICP-MS has been characterized for the first time. In this technique the MWDS has shown its efficiency to mitigate ethanol related matrix effects up to concentrations of 1% (w/w). Therefore, wine samples must be diluted to reduce the ethanol concentration up to this value. The results obtained have shown that the MWDS is a powerful device for the elemental analysis of wine samples in both ICP-AES and ICP-MS. In general, the MWDS has some attractive advantages for elemental wine analysis when compared to a conventional sample introduction system such

  6. Recent results from a continuous wave stepped frequency GPR system using a new ground-coupled multi-element antenna array

    Science.gov (United States)

    Linford, Neil; Linford, Paul; Payne, Andy

    2016-04-01

    The recent availability of multi-channel GPR instrumentation has allowed high-speed acquisition of densely sampled data sets over unprecedented areas of coverage. Such instrumentation has been of particular interest for the mapping of near-surface archaeological remains where the ability to collect GPR data at very close sample spacings (<0.1m) can provide a unique insight to both image and assess the survival of historic assets at a landscape scale. This paper reviews initial results obtained with a 3d-Radar GeoScope MkIV continuous wave stepped frequency (CWSF) GPR system utilising both initial prototypes and production versions of a newly introduced ground coupled antenna array. Whilst this system originally utilised an air-coupled antenna array there remained some debate over the suitability of an air-coupled antenna for all site conditions, particularly where a conductive surface layer, typical of many archaeological sites in the UK, may impede the transfer of energy into the ground. Encouraging results obtained from an initial prototype ground-coupled antenna array led to the introduction of a full width 22 channel G1922 version in March 2014 for use with the MkIV GeoScope console, offering faster acquisition across a wider frequency bandwidth (60MHz to 3GHz) with a cross-line 0.075m spacing between the individual elements in the array. Field tests over the Roman remains at Silchester corroborated the results from the earlier prototype, demonstrating an increased depth of penetration at the site compared to the previous air-coupled array. Further field tests were conducted with the G1922 over a range of sites, including Roman villa sites, formal post-medieval garden remains and a medieval farmstead to assess the response of the ground-coupled antenna to more challenging site conditions, particularly through water saturated soils. A full production DXG1820 version of the antenna became available for field work in 2015 offering optimisation of the individual

  7. Multi-element Analysis of variable sample matrices using collision/reaction cell inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Zahran, N.F.; Helal, A.I.; Amr, M.A.; Amr, M.A.; Al-saad, K.A.

    2008-01-01

    An ICP-MS with an octopole reaction/collision cell is used for the multielement determination of trace elements in water, plants, and soil samples. The use of a reaction or collision gas reduces serious spectral interferences from matrix elements such as Ar Cl or Ar Na. The background equivalent concentration (BEC) is reduced one order of magnitude at helium flow rate of 1 mL/min. Certified reference material namely , NIST Water-1643d, Tomato leaves 1573a, and Montana soil 2711 are used. The trace elements Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd and Pb are determined in the different matrices with a accuracy better than 8% to the certified values

  8. Forensic Discrimination of Concrete Pieces by Elemental Analysis of Acid-soluble Component with Inductively Coupled Plasma-Mass Spectrometry.

    Science.gov (United States)

    Kasamatsu, Masaaki; Igawa, Takao; Suzuki, Shinichi; Suzuki, Yasuhiro

    2018-01-01

    Since fragments of concrete can be evidence of crime, a determination of whether or not they come from the same origin is required. The authors focused on nitric acid-soluble components in the fragments of concrete. As a result of qualitative analysis with ICP-MS, it was confirmed that elements such as Cu, Zn, Rb, Sr, Zr, Ba, La, Ce, Nd, and Pb were contained in the fragments. After the nitric acid-soluble components in the fragments of concrete were separated by dissolving them in nitric acid, the concentrations of these elements in the dissolved solution were quantitatively determined by ICP-MS. The concentration ratios of nine elements compared to La were used as indicators. By comparing these indicators, it was possible to discriminate between the fragments of concrete.

  9. Unbalance Response Prediction for Rotors on Ball Bearings Using Speed and Load Dependent Nonlinear Bearing Stiffness

    Science.gov (United States)

    Fleming, David P.; Poplawski, J. V.

    2003-01-01

    Rolling-element bearing forces vary nonlinearly with bearing deflection. Thus an accurate rotordynamic analysis requires that bearing forces corresponding to the actual bearing deflection be utilized. For this work bearing forces were calculated by COBRA-AHS, a recently developed rolling-element bearing analysis code. Bearing stiffness was found to be a strong function of bearing deflection, with higher deflection producing markedly higher stiffness. Curves fitted to the bearing data for a range of speeds and loads were supplied to a flexible rotor unbalance response analysis. The rotordynamic analysis showed that vibration response varied nonlinearly with the amount of rotor imbalance. Moreover, the increase in stiffness as critical speeds were approached caused a large increase in rotor and bearing vibration amplitude over part of the speed range compared to the case of constant bearing stiffness. Regions of bistable operation were possible, in which the amplitude at a given speed was much larger during rotor acceleration than during deceleration. A moderate amount of damping will eliminate the bistable region, but this damping is not inherent in ball bearings.

  10. Atypical McMurry Cross-Coupling Reactions Leading to a New Series of Potent Antiproliferative Compounds Bearing the Key [Ferrocenyl-Ene-Phenol] Motif

    Directory of Open Access Journals (Sweden)

    Pascal Pigeon

    2014-07-01

    Full Text Available In the course of the preparation of a series of ferrocenyl derivatives of diethylstilbestrol (DES, in which one of the 4-hydroxyphenyl moieties was replaced by a ferrocenyl group, the McMurry reaction of chloropropionylferrocene with a number of mono-aryl ketones unexpectedly yielded the hydroxylated ferrocenyl DES derivatives, 5a–c, in poor yields (10%–16%. These compounds showed high activity on the hormone-independent breast cancer cell line MDA-MB-231 with IC50 values ranging from 0.14 to 0.36 µM. Surprisingly, non-hydroxylated ferrocenyl DES, 4, showed only an IC50 value of 1.14 µM, illustrating the importance of the hydroxyethyl function in this promising new series. For comparison, McMurry reactions of the shorter chain analogue chloroacetylferrocene were carried out to see the difference in behaviour with mono-aryl ketones versus a diaryl ketone. The effect of changing the length of the alkyl chain adjacent to the phenolic substituent of the hydroxylated ferrocenyl DES was studied, a mechanistic rationale to account for the unexpected products is proposed, and the antiproliferative activities of all of these compounds on MDA-MB-231 cells lines were measured and compared. X-ray crystal structures of cross-coupled products and of pinacol-pinacolone rearrangements are reported.

  11. Stabilizing gas bearing in free piston machines

    Science.gov (United States)

    Dhar, Manmohan (Inventor)

    1992-01-01

    In a free piston engine, to reduce dynamic loads on the reciprocating elements caused by a time varying pressure gradient across the gas bearing and close clearance seals provided therein, drain galleries are incorporated at the ends of the gas bearings to isolate the same, and circumferentially spaced grooves are incorporated in the close clearance seal region.

  12. Simultaneous determination of hydride and non-hydride forming elements by inductively coupled plasma optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Benzo, Z. [Instituto Venezolano de Investigaciones Cientificas, IVIC, Altos de Pipe, Caracas (Venezuela, Bolivarian Republic of); Matos-Reyes, M.N.; Cervera, M.L.; Guardia, M. de la, E-mail: m.luisa.cervera@uv.es [Department of Analytical Chemistry, University of Valencia, Valencia (Spain)

    2011-09-15

    The operating characteristics of a dual nebulization system were studied including instrumental and chemical conditions for the hydride generation and analytical figures of merit for both, hydride and non hydride forming elements. Analytical performance of the nebulization system was characterized by detection limits from 0.002 to 0.0026 {mu}g mL{sup -1} for the hydride forming elements and between 0.0034 and 0.0121 {mu}g mL{sup -1} for the non-hydride forming elements, relative standard deviation for 10 replicate measurements at 0.25 mg L{sup -1} level and recovery percentages between 97 and 103%. The feasibility of the system was demonstrated in the simultaneous determination of Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Zn, As, Bi, Sb, Se, and Te in the NIST 1549 (non-fat milk powder), NIST 1570a (spinach leaves), DORM-2 (dogfish muscle) and TORT-2 (lobster hepatopancreas) certified samples for trace elements. Results found were in good agreement with the certified ones. (author)

  13. Development of a partitioned finite volume-finite element fluid-structure interaction scheme for strongly-coupled problems

    CSIR Research Space (South Africa)

    Suliman, Ridhwaan

    2012-07-01

    Full Text Available -linear deformations are accounted for. As will be demonstrated, the finite volume approach exhibits similar disad- vantages to the linear Q4 finite element formulation when undergoing bending. An enhanced finite volume approach is discussed and compared with finite...

  14. Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Perdian, David C. [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser desorption/ionization mass spectrometric methods for the molecular analysis of biological tissues at atmospheric pressure and at high spatial resolution is also described. A spatial resolution is achieved that is able to analyze samples at the single cell level.

  15. Multi-element analysis of urine using dynamic reaction cell inductively coupled plasma mass spectrometry (ICP-DRC-MS — A practical application

    Directory of Open Access Journals (Sweden)

    Renata Brodzka

    2013-04-01

    Full Text Available Objectives: The method for the determination of As, Al, Cd, Ni, Pb (toxic elements and Cr, Co, Cu, Fe, Mn, Zn (essential elements in human urine by the use of Inductively Coupled Plasma Mass Spectrometry (quadrupole ICP-MS DRCe Elan, Perkin Elmer with the dynamic reaction cell (DRC was developed. Materials and Methods: The method has been applied for multi-element analysis of the urine of 16 non-exposed healthy volunteers and 27 workers employed in a copper smelter. The analysis was conducted after initial 10-fold dilution of the urine samples with 0,1% nitric acid. Rhodium was used as an internal standard. The method validation parameters such as detection limit, sensitivity, precision were described for all elements. Accuracy of the method was checked by the regular use of certified reference materials ClinCheck®-Control Urine (Recipe as well as by participation of the laboratory in the German External Quality Assessment Scheme (G-EQUAS. Results: The detection limits (DL 3s of the applied method were 0.025, 0.007, 0.002, 0.004, 0.004, 0.086, 0.037, 0.009, 0.016, 0.008, 0.064 (μg/l for Al, As, Cd, Cr, Co, Cu, Fe, Mn, Ni, Pb, Zn in urine, respectively. For each element linearity with correlation coefficient of at least 0.999 was determined. Spectral interferences from some of the ions were removed using DRC-e with addition of alternative gas: methane for cobalt, copper, cadmium, chromium, iron, manganese, nickel and rhodium, and oxygen for arsenic. Conclusions: The developed method allows to determine simultaneously eleven elements in the urine with low detection limits, high sensitivity and good accuracy. Moreover, the method is appropriate for the assessment of both environmental and occupational exposure.

  16. Determination of minor and trace elements in aromatic spices by micro-wave assisted digestion and inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Khan, Naeem; Choi, Ji Yeon; Nho, Eun Yeong; Jamila, Nargis; Habte, Girum; Hong, Joon Ho; Hwang, In Min; Kim, Kyong Su

    2014-09-01

    This study aimed at analyzing the concentrations of 23 minor and trace elements in aromatic spices by inductively coupled plasma-mass spectrometry (ICP-MS), after wet digestion by microwave system. The analytical method was validated by linearity, detection limits, precision, accuracy and recovery experiments, obtaining satisfactory values in all cases. Results indicated the presence of variable amounts of both minor and trace elements in the selected aromatic spices. Manganese was high in cinnamon (879.8 μg/g) followed by cardamom (758.1 μg/g) and clove (649.9 μg/g), strontium and zinc were high in ajwain (489.9 μg/g and 84.95 μg/g, respectively), while copper was high in mango powder (77.68 μg/g). On the whole some of the minor and essential trace elements were found to have good nutritional contribution in accordance to RDA. The levels of toxic trace elements, including As, Cd, and Pb were very low and did not found to pose any threat to consumers. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Comparative study of injection into a pneumatic nebuliser and tungsten coil electrothermal vaporisation for the determination of rare earth elements by inductively coupled plasma optical emission spectrometry

    International Nuclear Information System (INIS)

    Dittrich, K.

    1988-01-01

    Injection into a pneumatic nebuliser and vaporisation using a tungsten coil electrothermal vaporisation system, with a 3-kW argon-nitrogen inductively coupled plasma (ICP), are compared for the determination of the rare earth elements. The sampling efficiency and thus also the absolute power of detection of the tungsten coil ICP optical emission spectrometric (ICP-OES) technique are better by two orders of magnitude, than the injection technique. The absolute detection limits for the rare earth elements are at the pg level; for the refractory rare earth elements (Er, La, Lu and Y), they are lower than those obtained by graphite furnace atomic absorption spectrometry, whereas for the other rare earth elements (Eu, Sc, Tm and Yb), the detection limits are comparable. With injection of samples into a pneumatic nebuliser and ICP-OES, matrix effects are low and absolute amounts of the order of mg of the rare earth matrix can be tolerated, giving relative detection limits down to 1 μg g -1 . The amount of rare earth matrix that can be tolerated with the tungsten-coil atomiser is two orders of magnitude lower. Thus the relatively detection limits of the two methods are of the same order, although the matrix effects are considerably higher with the tungsten coil. (author)

  18. Comparative measurements of mineral elements in milk powders with laser-induced breakdown spectroscopy and inductively coupled plasma atomic emission spectroscopy.

    Science.gov (United States)

    Lei, W Q; El Haddad, J; Motto-Ros, V; Gilon-Delepine, N; Stankova, A; Ma, Q L; Bai, X S; Zheng, L J; Zeng, H P; Yu, J

    2011-07-01

    Mineral elements contained in commercially available milk powders, including seven infant formulae and one adult milk, were analyzed with inductively coupled plasma atomic emission spectrometry (ICP-AES) and laser-induced breakdown spectroscopy (LIBS). The purpose of this work was, through a direct comparison of the analytical results, to provide an assessment of the performance of LIBS, and especially of the procedure of calibration-free LIBS (CF-LIBS), to deal with organic compounds such as milk powders. In our experiments, the matrix effect was clearly observed affecting the analytical results each time laser ablation was employed for sampling. Such effect was in addition directly observed by determining the physical parameters of the plasmas induced on the different samples. The CF-LIBS procedure was implemented to deduce the concentrations of Mg and K with Ca as the internal reference element. Quantitative analytical results with CF-LIBS were validated with ICP-AES measurements and nominal concentrations specified for commercial milks. The obtained good results with the CF-LIBS procedure demonstrate its capacity to take into account the difference in physical parameters of the plasma in the calculation of the concentrations of mineral elements, which allows a significant reduction of the matrix effect related to laser ablation. We finally discuss the way to optimize the implementation of the CF-LIBS procedure for the analysis of mineral elements in organic materials.

  19. Mathematical simulation of bearing ring grinding process

    Science.gov (United States)

    Koltunov, I. I.; Gorbunova, T. N.; Tumanova, M. B.

    2018-03-01

    The paper suggests the method of forming a solid finite element model of the bearing ring. Implementation of the model allowed one to evaluate the influence of the inner cylindrical surface grinding scheme on the ring shape error.

  20. Modeling of dynamically loaded hydrodynamic bearings at low Sommerfeld numbers

    DEFF Research Database (Denmark)

    Thomsen, Kim

    Current state of the art within the wind industry dictates the use of conventional rolling element bearings for main bearings. As wind turbine generators increase in size and output, so does the size of the main bearings and accordingly also the cost and potential risk of failure modes. The cost...... and failure risk of rolling element bearings do, however, grow exponentially with the size. Therefore hydrodynamic bearings can prove to be a competitive alternative to the current practice of rolling element bearings and ultimately help reducing the cost and carbon footprint of renewable energy generation....... The challenging main bearing operation conditions in a wind turbine pose a demanding development task for the design of a hydrodynamic bearing. In general these conditions include operation at low Reynolds numbers with frequent start and stop at high loads as well as difficult operating conditions dictated...

  1. Speciation of trace elements in biological samples by nuclear analytical and related techniques coupled with chemical and biochemical separation

    International Nuclear Information System (INIS)

    Chen, C.Y.; Gao, Y.X.; Li, B.; Yu, H.W.; Li, Y.F.; Sun, J.; Chai, Z.F.

    2005-01-01

    In the past, most analytical problems relating to biological systems were addressed by measuring the total concentrations of elements. Now there is increasing interest of the importance of their chemical forms, in which an element is present in biological systems, e.g., the oxidation state, the binding state with macromolecules, or even the molecular structure. The biological effects of chromium, which is classified as an essential nutrient, are dependent upon its oxidation. state. In general, trivalent chromium is biochemically active, whereas hexavalent chromium is considered to be toxic. Mercury is one of serious environmental persistent pollutants. However, organic forms of mercury are known to possess much higher toxicity than inorganic mercury. Therefore, information on speciation is critically required in order to better understanding of their bioavailability, metabolism, transformation, and toxicity in vivo. Recently, chemical speciation of selenium, mercury, copper, zinc, iron, and so on, has been investigated by INAA, ICP-MS, XRF, EXAFS and related techniques combined with chemical and biochemical separation (extraction, chromatography, gel electrophoresis, etc.). INAA, XRF, and ICP-MS have superior advantages in aspect of multielemental analysis with high accuracy and sensitivity, which render the possibility of analyzing various elements of interest simultaneously. These offline or online techniques have been flexibly applied to different biological matrixes, such as human hair, serum, urine, various tissues and organs in our researches. In addition, EXAFS provides structural information about the moiety of metal centers up to a distance of approximately 4-5 Anstrom. For instance, hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Imbalance of elements, such as Se, Zn, Fe, Cu, Cd, Ca, etc., has been found in the whole blood or serum of patients with HCC. We found that the profiles of Se, Cd, Fe, Zn and Cu-containing proteins

  2. Multi-element quantification of ancient/historic glasses by laser ablation inductively coupled plasma mass spectrometry using sum normalization calibration

    International Nuclear Information System (INIS)

    Elteren, Johannes T. van; Tennent, Norman H.; Selih, Vid S.

    2009-01-01

    Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for quantitative analysis of ancient/historic glasses is subject to calibration issues which have been addressed in this work. Since ancient/historic glasses have widely ranging matrix compositions, a complementary analysis by an alternative method is generally employed to determine at least one major element which can be used as an internal standard. We demonstrate that such a complementary analysis is unnecessary using a so-called sum normalization calibration technique (mathematically formulated) by simultaneous measurement of 54 elements and normalizing them to 100% [w/w] based on their corresponding oxide concentrations. The crux of this approach is that by assuming a random internal standard concentration of a particular major oxide, e.g. SiO 2 , the normalization algorithm varies the internal standard concentration until the cumulated concentrations of all 54 elemental oxides reach 100% [w/w]. The fact that 54 elements are measured simultaneously predetermines the laser ablation mode to rastering. Nine glass standards, some replicating historic compositions, were used for calibration. The linearity of the calibration graphs (forced through the origin) represented by the relative standard deviations in the slope were between 0.1 and 6.6% using SiO 2 as an internal standard. This allows high-accuracy determination of elemental oxides as confirmed by good agreement between found and reported values for major and minor elemental oxides in some synthetic glasses with typical medieval composition (European Science Foundation 151 and 158). Also for trace elemental concentrations of lanthanides in a reference glass (P and H Developments Ltd. DLH7, a base glass composition with nominally 75 μg g -1 elements added) accurate data were obtained. Interferences from polyatomic species and doubly charged species on the masses of trace elements are possible, depending on the base composition of the

  3. Determination of 20 trace elements and arsenic species for a realgar-containing traditional Chinese medicine Niuhuang Jiedu tablets by direct inductively coupled plasma-mass spectrometry and high performance liquid chromatography-inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Jin, Pengfei; Liang, Xiaoli; Xia, Lufeng; Jahouh, Farid; Wang, Rong; Kuang, Yongmei; Hu, Xin

    2016-01-01

    Niuhuang Jiedu tablet (NHJDT) is a realgar-containing traditional Chinese medicine. A direct inductively coupled plasma-mass spectrometry (ICP-MS) method for the simultaneous determination of 20 trace elements (Mg, K, Ca, Na, Fe, As, Zn, Sr, Ba, Cu, Mn, Ni, Pb, V, Cr, Se, Co, Mo, Cd, Hg) in NHJDT, as well as in water, gastric fluid and intestinal fluid was established. Meanwhile, a high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) method was developed for the determination of arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and for the identification of arsenobetaine (AsB) and arsenocholine (AsC) in these extracts. Both methods were fully validated in the respect of linearity, sensitivity, precision, stability and accuracy. The reliability of the ICP-MS method was further evaluated using a certified standard reference material prepared from dried tomato leaves (NIST, SRM 1572a). The analysis showed that some manufacturers formulated lower amount of realgar than required in the Chinese Pharmacopoeia (ChP) in their preparations. In addition, almost same extraction profiles for total As and inorganic As were found in water and in gastrointestinal fluids, while higher extraction rates for other 19 elements were observed in gastrointestinal fluids. Our findings show that the toxicities of Hg, Cu, Cd and Pb in NHJDP are low, while the real As toxicity in NHJDT should be deeply investigated. Copyright © 2015 Elsevier GmbH. All rights reserved.

  4. A 3D mixed frame element with multi-axial coupling for thin-walled structures with damage

    Directory of Open Access Journals (Sweden)

    D. Addessi

    2014-07-01

    Full Text Available A 3D mixed beam finite element is presented, modeling the warping of the cross-sections as an independent kinematic field. The beam formulation is derived on the basis of the Hu-Washizu variational principle, expressed as function of four independent fields: the standard displacements, strains and stresses and the additional warping displacement. This is interpolated along the beam axis and on the cross-section, by placing on it a regular grid of interpolation points and adopting Lagrange polynomials. The warping degrees of freedom defined at the cross-section interpolation points are condensed, thus preserving the element matrix and vector sizes. A fiber discretization of the cross-sections is adopted. The constitutive relationship at the midpoint of each fiber is based on an isotropic damage model for brittle-like materials, distinguishing between the damage variables in tension and in compression to properly describe the unilateral effect. An efficient algorithm is formulated for the element state determination, based on a consistent linearization of the governing equations. A simple numerical application on a cantilever beam with torsion in the linear elastic range is presented and two torsion tests on plain concrete beams are performed, by comparing the numerical results with the experimental outcomes.

  5. An immunity-triggering effector from the Barley smut fungus Ustilago hordei resides in an Ustilaginaceae-specific cluster bearing signs of transposable element-assisted evolution.

    Directory of Open Access Journals (Sweden)

    Shawkat Ali

    2014-07-01

    Full Text Available The basidiomycete smut fungus Ustilago hordei was previously shown to comprise isolates that are avirulent on various barley host cultivars. Through genetic crosses we had revealed that a dominant avirulence locus UhAvr1 which triggers immunity in barley cultivar Hannchen harboring resistance gene Ruh1, resided within an 80-kb region. DNA sequence analysis of this genetically delimited region uncovered the presence of 7 candidate secreted effector proteins. Sequence comparison of their coding sequences among virulent and avirulent parental and field isolates could not distinguish UhAvr1 candidates. Systematic deletion and complementation analyses revealed that UhAvr1 is UHOR_10022 which codes for a small effector protein of 171 amino acids with a predicted 19 amino acid signal peptide. Virulence in the parental isolate is caused by the insertion of a fragment of 5.5 kb with similarity to a common U. hordei transposable element (TE, interrupting the promoter of UhAvr1 and thereby changing expression and hence recognition of UhAVR1p. This rearrangement is likely caused by activities of TEs and variation is seen among isolates. Using GFP-chimeric constructs we show that UhAvr1 is induced only in mated dikaryotic hyphae upon sensing and infecting barley coleoptile cells. When infecting Hannchen, UhAVR1p causes local callose deposition and the production of reactive oxygen species and necrosis indicative of the immune response. UhAvr1 does not contribute significantly to overall virulence. UhAvr1 is located in a cluster of ten effectors with several paralogs and over 50% of TEs. This cluster is syntenous with clusters in closely-related U. maydis and Sporisorium reilianum. In these corn-infecting species, these clusters harbor however more and further diversified homologous effector families but very few TEs. This increased variability may have resulted from past selection pressure by resistance genes since U. maydis is not known to trigger immunity

  6. An Immunity-Triggering Effector from the Barley Smut Fungus Ustilago hordei Resides in an Ustilaginaceae-Specific Cluster Bearing Signs of Transposable Element-Assisted Evolution

    KAUST Repository

    Ali, Shawkat

    2014-07-03

    The basidiomycete smut fungus Ustilago hordei was previously shown to comprise isolates that are avirulent on various barley host cultivars. Through genetic crosses we had revealed that a dominant avirulence locus UhAvr1 which triggers immunity in barley cultivar Hannchen harboring resistance gene Ruh1, resided within an 80-kb region. DNA sequence analysis of this genetically delimited region uncovered the presence of 7 candidate secreted effector proteins. Sequence comparison of their coding sequences among virulent and avirulent parental and field isolates could not distinguish UhAvr1 candidates. Systematic deletion and complementation analyses revealed that UhAvr1 is UHOR_10022 which codes for a small effector protein of 171 amino acids with a predicted 19 amino acid signal peptide. Virulence in the parental isolate is caused by the insertion of a fragment of 5.5 kb with similarity to a common U. hordei transposable element (TE), interrupting the promoter of UhAvr1 and thereby changing expression and hence recognition of UhAVR1p. This rearrangement is likely caused by activities of TEs and variation is seen among isolates. Using GFP-chimeric constructs we show that UhAvr1 is induced only in mated dikaryotic hyphae upon sensing and infecting barley coleoptile cells. When infecting Hannchen, UhAVR1p causes local callose deposition and the production of reactive oxygen species and necrosis indicative of the immune response. UhAvr1 does not contribute significantly to overall virulence. UhAvr1 is located in a cluster of ten effectors with several paralogs and over 50% of TEs. This cluster is syntenous with clusters in closely-related U. maydis and Sporisorium reilianum. In these corn-infecting species, these clusters harbor however more and further diversified homologous effector families but very few TEs. This increased variability may have resulted from past selection pressure by resistance genes since U. maydis is not known to trigger immunity in its corn host.

  7. An Immunity-Triggering Effector from the Barley Smut Fungus Ustilago hordei Resides in an Ustilaginaceae-Specific Cluster Bearing Signs of Transposable Element-Assisted Evolution

    KAUST Repository

    Ali, Shawkat; Laurie, John D.; Linning, Rob; Cervantes-Chá vez, José Antonio; Gaudet, Denis; Bakkeren, Guus

    2014-01-01

    The basidiomycete smut fungus Ustilago hordei was previously shown to comprise isolates that are avirulent on various barley host cultivars. Through genetic crosses we had revealed that a dominant avirulence locus UhAvr1 which triggers immunity in barley cultivar Hannchen harboring resistance gene Ruh1, resided within an 80-kb region. DNA sequence analysis of this genetically delimited region uncovered the presence of 7 candidate secreted effector proteins. Sequence comparison of their coding sequences among virulent and avirulent parental and field isolates could not distinguish UhAvr1 candidates. Systematic deletion and complementation analyses revealed that UhAvr1 is UHOR_10022 which codes for a small effector protein of 171 amino acids with a predicted 19 amino acid signal peptide. Virulence in the parental isolate is caused by the insertion of a fragment of 5.5 kb with similarity to a common U. hordei transposable element (TE), interrupting the promoter of UhAvr1 and thereby changing expression and hence recognition of UhAVR1p. This rearrangement is likely caused by activities of TEs and variation is seen among isolates. Using GFP-chimeric constructs we show that UhAvr1 is induced only in mated dikaryotic hyphae upon sensing and infecting barley coleoptile cells. When infecting Hannchen, UhAVR1p causes local callose deposition and the production of reactive oxygen species and necrosis indicative of the immune response. UhAvr1 does not contribute significantly to overall virulence. UhAvr1 is located in a cluster of ten effectors with several paralogs and over 50% of TEs. This cluster is syntenous with clusters in closely-related U. maydis and Sporisorium reilianum. In these corn-infecting species, these clusters harbor however more and further diversified homologous effector families but very few TEs. This increased variability may have resulted from past selection pressure by resistance genes since U. maydis is not known to trigger immunity in its corn host.

  8. A Novel Integral 5-DOFs Hybrid Magnetic Bearing with One Permanent Magnet Ring Used for Turboexpander

    Directory of Open Access Journals (Sweden)

    Bangcheng Han

    2014-01-01

    Full Text Available We propose a novel combined five-degrees-of-freedom (5-DOFs hybrid magnetic bearing (HMB with only one permanent magnet ring (PMR used for turboexpanders. It has two radial magnetic bearing (RMB units; each has four poles and one thrust magnetic bearing (TMB to control 5-DOFs. Based on one PMR, the bias flux of the two radial magnetic bearing units and the one thrust magnetic bearing unit is constructed. As a result, ultra-high-speed, lower power loss, small size, and low cost can be achieved. Furthermore, the equivalent magnetic circuit method and 3D finite element method (FEM are used to model and analyze the combined 5-DOFs HMB. The force-current, force-position, torque-coil currents, the torque-angle position, and the stiffness models of the combined 5-DOFs HMB are given. Moreover, its coupling problems between the RMB units and the AMB unit are also proposed in this paper. An example is given to clarify the mathematical models and the coupling problems, and the linearized models are proposed for the follow-up controller design.

  9. An evaluation of microwave-assisted fusion and microwave-assisted acid digestion methods for determining elemental impurities in carbon nanostructures using inductively coupled plasma optical emission spectrometry

    KAUST Repository

    Patole, Shashikant P.

    2015-10-21

    It is common for as-prepared carbon nanotube (CNT) and graphene samples to contain remnants of the transition metals used to catalyze their growth; contamination may also leave other trace elemental impurities in the samples. Although a full quantification of impurities in as-prepared samples of carbon nanostructures is difficult, particularly when trace elements are intercalated or encapsulated within a protective layer of graphitic carbon, reliable information is essential for reasons such as quantifying the adulteration of physico-chemical properties of the materials and for evaluating environmental issues. Here, we introduce a microwave-based fusion method to degrade single- and double-walled CNTs and graphene nanoplatelets into a fusion flux thereby thoroughly leaching all metallic impurities. Subsequent dissolution of the fusion product in diluted hydrochloric and nitric acid allowed us to identify their trace elemental impurities using inductively coupled plasma optical emission spectrometry. Comparisons of the results from the proposed microwave-assisted fusion method against those of a more classical microwave-assisted acid digestion approach suggest complementarity between the two that ultimately could lead to a more reliable and less costly determination of trace elemental impurities in carbon nanostructured materials. Graphical abstract A method for the complete digestion of carbon nanostructures has been demonstrated. Photographs (on the left side) show zirconium crucibles containing SWCNTs with flux of Na2CO3 and K2CO3, before and after microwave fusion; (on the right side) the appearance of the final solutions containing dissolved samples, from microwave-assisted fusion and microwave-assisted acid digestion. These solutions were used for determining the trace elemental impurities by ICP‒OES.

  10. An assumed mode method and finite element method investigation of the coupled vibration in a flexible-disk rotor system with lacing wires

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Shui-Ting; Huang, Hong-Wu [Hunan University, Changsha (China); Chiu, Yi-Jui; Yu, Guo-Fei [Xiamen University of Technology, Xiamen (China); Yang, Chia-Hao [Taipei Chengshih University of Science and Technology, Taipei (China); Jian, Sheng-Rui [I-Shou University, Kaohsiung (China)

    2017-02-15

    The Assumed mode method (AMM) and Finite element method (FEM) were used. Their results were compared to investigate the coupled shaft-torsion, disk-transverse, and blade-bending vibrations in a flexible-disk rotor system. The blades were grouped with a spring. The flexible-disk rotor system was divided into three modes of coupled vibrations: Shaft-disk-blade, disk-blade, and blade-blade. Two new modes of coupled vibrations were introduced, namely, lacing wires-blade and lacing wires-disk-blade. The patterns of change of the natural frequencies and mode shapes of the system were discussed. The results showed the following: first, mode shapes and natural frequencies varied, and the results of the AMM and FEM differed; second, numerical calculation results showed three influencing factors on natural frequencies, namely, the lacing wire constant, the lacing wire location, and the flexible disk; lastly, the flexible disk could affect the stability of the system as reflected in the effect of the rotational speed.

  11. Classification of Antarctic algae by applying Kohonen neural network with 14 elements determined by inductively coupled plasma optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Balbinot, L. [Departamento de Quimica Analitica-Instituto de Quimica-Unicamp, PO Box 6154, CEP: 13083-971, Campinas, SP (Brazil); Smichowski, P. [Comision Nacional de Energia Atomica, Unidad de Actividad Quimica, Centro Atomico Constituyentes, Av. Gral Paz 1499, B1650KNA, San Martin, Provincia de Buenos Aires (Argentina); Farias, S. [Comision Nacional de Energia Atomica, Unidad de Actividad Quimica, Centro Atomico Constituyentes, Av. Gral Paz 1499, B1650KNA, San Martin, Provincia de Buenos Aires (Argentina); Arruda, M.A.Z. [Departamento de Quimica Analitica-Instituto de Quimica-Unicamp, PO Box 6154, CEP: 13083-971, Campinas, SP (Brazil); Vodopivez, C. [Instituto Antartico Argentino, Cerrito 1010, C1248AAZ, Buenos Aires (Argentina); Poppi, R.J. [Departamento de Quimica Analitica-Instituto de Quimica-Unicamp, PO Box 6154, CEP: 13083-971, Campinas, SP (Brazil)]. E-mail: ronei@iqm.unicamp.br

    2005-06-30

    Optical emission spectrometers can generate results, which sometimes are not easy to interpret, mainly when the analyses involve classifications. To make simultaneous data interpretation possible, the Kohonen neural network is used to classify different Antarctic algae according to their taxonomic groups from the determination of 14 analytes. The Kohonen neural network architecture used was 5x5 neurons, thus reducing 14-dimension input data to two-dimensional space. The input data were 14 analytes (As, Co, Cu, Fe, Mn, Sr, Zn, Cd, Cr, Mo, Ni, Pb, Se, V) with their concentrations, determined by inductively coupled plasma optical emission spectrometry in 11 different species of algae. Three taxonomic groups (Rhodophyta, Phaeophyta and Cholorophyta) can be differentiated and classified through only their Cu content.

  12. Classification of Antarctic algae by applying Kohonen neural network with 14 elements determined by inductively coupled plasma optical emission spectrometry

    International Nuclear Information System (INIS)

    Balbinot, L.; Smichowski, P.; Farias, S.; Arruda, M.A.Z.; Vodopivez, C.; Poppi, R.J.

    2005-01-01

    Optical emission spectrometers can generate results, which sometimes are not easy to interpret, mainly when the analyses involve classifications. To make simultaneous data interpretation possible, the Kohonen neural network is used to classify different Antarctic algae according to their taxonomic groups from the determination of 14 analytes. The Kohonen neural network architecture used was 5x5 neurons, thus reducing 14-dimension input data to two-dimensional space. The input data were 14 analytes (As, Co, Cu, Fe, Mn, Sr, Zn, Cd, Cr, Mo, Ni, Pb, Se, V) with their concentrations, determined by inductively coupled plasma optical emission spectrometry in 11 different species of algae. Three taxonomic groups (Rhodophyta, Phaeophyta and Cholorophyta) can be differentiated and classified through only their Cu content

  13. Improving plasmonic waveguides coupling efficiency using nanoantennas

    DEFF Research Database (Denmark)

    Andryieuski, Andrei; Malureanu, Radu; Bouillard, Jean-Sebastien

    2012-01-01

    . The classical dipole antenna scheme can be improved by changing the nanoantenna geometry, adding constructive elements such as reflecting bars and mirrors and using arrays of antennas. The modelling designates that the coupling efficiency from a vertical fiber to a plasmonic waveguide can be improved more than......Plasmonic waveguides bear a lot of potential for photonic applications. However, one of the challenges for implementing them in devices is the low coupling efficiency to and from optical fibers. We report on our approach to facilitate the coupling efficiency with the use of metallic nanoantennas...... in 180 times in comparison with a direct fiber-waveguide coupling. Pros and cons of each configuration are discussed. Fabrication and characterisation results are reported....

  14. Ultra-sensitive quantification of lysozyme based on element chelate labeling and capillary electrophoresis–inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Yang, MingWei; Wu, WeiHua; Ruan, YaJuan; Huang, LiMei; Wu, Zujian; Cai, Yong; Fu, FengFu

    2014-01-01

    Graphical abstract: An ultra-sensitive method for the determination of lysozyme was developed based on the Gd 3+ chelate labeling and CE–ICP–MS. The proposed method has an extremely low detection limit of 3.89 attomole and has been successfully used to detect lysozyme in saliva sample, showing excellent reliability. The success of the present method provides a new possibility for biological assays and clinical diagnoses. -- Highlights: •An ultra-sensitive method for detecting lysozyme based on CE–ICP–MS was described. •The proposed method has an extremely low detection limit of 3.89 attomole. •It can be used to detect trace lysozyme in saliva sample with a satisfied recovery. •The method provides a new potential for sensitive detection of low-abundant proteins. -- Abstract: In this study, an ultra-sensitive method for the quantification of lysozyme based on the Gd 3+ diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid labeling and capillary electrophoresis–inductively coupled plasma mass spectrometry (CE–ICP–MS) was described. The Gd 3+ -tagged lysozyme was effectively separated by capillary electrophoresis (CE) and sensitively determined by inductively coupled plasma mass spectrometry (ICP–MS). Based on the gadolinium-tagging and CE–ICP–MS, the lysozyme was determined within 12 min with an extremely low detection limit of 3.89 attomole (3.89 × 10 −11 mol L −1 for 100 nL of sample injection) and a RSD < 6% (n = 5). The proposed method has been successfully used to detect lysozyme in saliva samples with a recovery of 91–106%, suggesting that our method is sensitive and reliable. The success of the present method provides a new potential for the biological assays and sensitive detection of low-abundant proteins

  15. Molecular phylogeny and SNP variation of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) derived from genome sequences.

    Science.gov (United States)

    Cronin, Matthew A; Rincon, Gonzalo; Meredith, Robert W; MacNeil, Michael D; Islas-Trejo, Alma; Cánovas, Angela; Medrano, Juan F

    2014-01-01

    We assessed the relationships of polar bears (Ursus maritimus), brown bears (U. arctos), and black bears (U. americanus) with high throughput genomic sequencing data with an average coverage of 25× for each species. A total of 1.4 billion 100-bp paired-end reads were assembled using the polar bear and annotated giant panda (Ailuropoda melanoleuca) genome sequences as references. We identified 13.8 million single nucleotide polymorphisms (SNP) in the 3 species aligned to the polar bear genome. These data indicate that polar bears and brown bears share more SNP with each other than either does with black bears. Concatenation and coalescence-based analysis of consensus sequences of approximately 1 million base pairs of ultraconserved elements in the nuclear genome resulted in a phylogeny with black bears as the sister group to brown and polar bears, and all brown bears are in a separate clade from polar bears. Genotypes for 162 SNP loci of 336 bears from Alaska and Montana showed that the species are genetically differentiated and there is geographic population structure of brown and black bears but not polar bears.

  16. Sequential determination of environmental levels of isotopic thorium, uranium and the light rare earth elements within the terrestrial food chain by induced coupled plasma (ICP) and alpha spectrometry

    International Nuclear Information System (INIS)

    Linsalata, P.; Morse, R.; Ford, H.

    1986-01-01

    A radioecological study designed to measure soil to plant and soil to animal (livestock) transfer of Th, U, Ra and the light rare earth elements (REE) in typical and naturally-enhanced radiation environments required the development of radiochemical methods suitable for low-level determinations in a broad suite of environmental matrices including soil, edible vegetables and vegetation, and the major organs and tissues of various livestock. Earlier work has demonstrate the reliability of the methods summarized here for measuring the isotopic thorium and REE content of human feces, and that in the edible portions of various vegetables grown under field conditions. The very high degree of biological discrimination against Th and REE uptake in plants as well as in animal soft tissues necessitated the analysis of typical sample masses of 1-4 kg (fresh weight) to insure reasonably precise (eg., 10-20%) concentration estimates for most of the elements and isotopes of interest. As a result of the ''bone-seeking'' nature and relatively long retention times for these elements in skeletal tissue, typical analytical masses required for analysis of bone range from 40 to 70 g (fresh weight) except for the REE's in which a larger aliquot is recommended when determination is by induced coupled plasma spectrometry

  17. Rare earth elements determined in Antarctic ice by inductively coupled plasma-Time of flight, quadrupole and sector field-mass spectrometry: An inter-comparison study

    International Nuclear Information System (INIS)

    Dick, D.; Wegner, A.; Gabrielli, P.; Ruth, U.; Barbante, C.; Kriews, M.

    2008-01-01

    Inductively coupled plasma mass spectrometry (ICP-MS) is a suitable tool for multi-element analysis at low concentration levels. Rare earth element (REE) determinations in standard reference materials and small volumes of molten ice core samples from Antarctica have been performed with an ICP-time of flight-MS (ICP-TOF-MS) system. Recovery rates for REE in e.g. SPS-SW1 amounted to ∼103%, and the relative standard deviations were 3.4% for replicate analysis at REE concentrations in the lower ng L -1 range. Analyses of REE concentrations in Antarctic ice core samples showed that the ICP-TOF-MS technique meets the demands of restricted sample mass. The data obtained are in good agreement with ICP-Quadrupole-MS (ICP-Q-MS) and ICP-Sector Field-MS (ICP-SF-MS) results. The ICP-TOF-MS system determines accurately and precisely REE concentrations exceeding 5 ng L -1 while between 0.5 and 5 ng L -1 accuracy and precision are element dependent

  18. Rolling Bearing Life Prediction, Theory, and Application

    Science.gov (United States)

    Zaretsky, Erwin V.

    2016-01-01

    A tutorial is presented outlining the evolution, theory, and application of rolling-element bearing life prediction from that of A. Palmgren, 1924; W. Weibull, 1939; G. Lundberg and A. Palmgren, 1947 and 1952; E. Ioannides and T. Harris, 1985; and E. Zaretsky, 1987. Comparisons are made between these life models. The Ioannides-Harris model without a fatigue limit is identical to the Lundberg-Palmgren model. The Weibull model is similar to that of Zaretsky if the exponents are chosen to be identical. Both the load-life and Hertz stress-life relations of Weibull, Lundberg and Palmgren, and Ioannides and Harris reflect a strong dependence on the Weibull slope. The Zaretsky model decouples the dependence of the critical shear stress-life relation from the Weibull slope. This results in a nominal variation of the Hertz stress-life exponent. For 9th- and 8th-power Hertz stress-life exponents for ball and roller bearings, respectively, the Lundberg-Palmgren model best predicts life. However, for 12th- and 10th-power relations reflected by modern bearing steels, the Zaretsky model based on the Weibull equation is superior. Under the range of stresses examined, the use of a fatigue limit would suggest that (for most operating conditions under which a rolling-element bearing will operate) the bearing will not fail from classical rolling-element fatigue. Realistically, this is not the case. The use of a fatigue limit will significantly overpredict life over a range of normal operating Hertz stresses. (The use of ISO 281:2007 with a fatigue limit in these calculations would result in a bearing life approaching infinity.) Since the predicted lives of rolling-element bearings are high, the problem can become one of undersizing a bearing for a particular application. Rules had been developed to distinguish and compare predicted lives with those actually obtained. Based upon field and test results of 51 ball and roller bearing sets, 98 percent of these bearing sets had acceptable

  19. Quantitative analysis of major and trace elements in NH4HF2-modified silicate rock powders by laser ablation - inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Zhang, Wen; Hu, Zhaochu; Liu, Yongsheng; Yang, Wenwu; Chen, Haihong; Hu, Shenghong; Xiao, Hongyan

    2017-08-29

    In this paper, we described a NH 4 HF 2 digestion method as sample preparation for the rapid determination of major and trace elements in silicate rocks using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). Sample powders digested by NH 4 HF 2 at 230 °C for 3 h form ultrafine powders with a typical grain size d 80  rocks have a consistent grain morphology and size, allowing us to produce pressed powder pellets that have excellent cohesion and homogeneity suitable for laser ablation micro-analysis without the addition of binder. The influences of the digestion parameters were investigated and optimized, including the evaporation stage of removing residual NH 4 HF 2 , sample homogenization, selection of the digestion vessel and calibration strategy of quantitative analysis. The optimized NH 4 HF 2 digestion method was applied to dissolve six silicate rock reference materials (BCR-2, BHVO-2, AGV-2, RGM-2, GSP-2, GSR-1) covering a wide range of rock types. Ten major elements and thirty-five trace elements were simultaneously analyzed by LA-ICP-MS. The analytical results of the six reference materials generally agreed with the recommended values, with discrepancies of less than 10% for most elements. The analytical precision is within 5% for most major elements and within 10% for most trace elements. Compared with previous methods of LA-ICP-MS bulk analysis, our method enables the complete dissolution of refractory minerals, such as zircon, in intermediate-acidic intrusive rocks and limits contamination as well as the loss of volatile elements. Moreover, there are many advantages for the new technique, including reducing matrix effects between reference materials and samples, spiking the internal standard simply and feasibly and sample batch processing. The applicability filed of the new technique in this study was focused on the whole-rock analysis of igneous rock samples, which are from basic rocks to acid rocks (45% rock analysis

  20. On-line coupling of the MAT 251 with a Carlo Erba elemental analyzer for carbon isotope ratio measurements

    International Nuclear Information System (INIS)

    Pichlmayer, F.

    1986-06-01

    For carbon isotope investigations with a moderate precision demand of about 0.2 per mil in the isotope ratio fast and reliable results are attained by on line combination of the ANA 1500 Elemental Analyzer and the MAT 251 Isotope Mass Spectrometer. The crucial point hereof is the gas splitting device. By proper design and adjustment of the analytical parameters, good sample efficiency and a sharp CO 2 bulk within the He stream is reached. The main characteristics of this combined equipment are described and some isotopic results of organic and anorganic carbon in lake sediment-samples are given as well as deltasup1 3 C-analyses of spiritous liquors. (Author)

  1. Coupled 3D neutronic and thermohydraulic calculations for a compact fuel element with disperse UMo fuel at FRM II

    International Nuclear Information System (INIS)

    Breitkreutz, H.; Roehrmoser, A.; Petry, W.

    2010-01-01

    The newly developed X 2 program system is intended to be used for high-detail 3D calculations on compact research reactor cores. Using this system, the efforts to calculate scenarios for a new fuel element for FRM II using disperse UMo (8wt% Mo, 50% enrichment) are continued. By now, a radial symmetric core model with averaged built-in components for the D 2 O tank is used. Two different scenarios are compared: The minimum fuel density of 7.5 g U/cm 3 and 8.0 g U/cm 3 with 60 days cycle length. In addition, two 'flux loss compensating' scenarios based on 8.0 g U/cm 3 with 10% higher power/longer reactor cycles are regarded. (author)

  2. Discrimination of Inrush from Fault Currents in Power Transformers Based on Equivalent Instantaneous Inductance Technique Coupled with Finite Element Method

    Directory of Open Access Journals (Sweden)

    M. Jamali

    2011-09-01

    Full Text Available The phenomenon of magnetizing inrush is a transient condition, which occurs primarily when a transformer is energized. The magnitude of inrush current may be as high as ten times or more times of transformer rated current that causes malfunction of protection system. So, for safe running of a transformer, it is necessary to distinguish inrush current from fault currents. In this paper, an equivalent instantaneous inductance (EII technique is used to discriminate inrush current from fault currents. For this purpose, a three-phase power transformer has been simulated in Maxwell software that is based on finite elements. This three-phase power transformer has been used to simulate different conditions. Then, the results have been used as inputs in MATLAB program to implement the equivalent instantaneous inductance technique. The results show that in the case of inrush current, the equivalent instantaneous inductance has a drastic variation, while it is almost constant in the cases of fault conditions.

  3. Elemental quantification of airborne particulate matter by instrumental neutron activation analysis and induced coupled plasma mass spectrometry analysis

    International Nuclear Information System (INIS)

    Hidayat, Achmad; Djojosubroto, Harjoto; Rukihati; Sutisna

    1999-01-01

    Airborne particulate were collected using Gent sampler for PM 10 and using high volume sampler for total suspended particulate (TSP). PM 10 sampling was carried out in Bandung during period of January to December 1997. Whereas TSP samples were collected at Serpong (rural area) and Jakarta (urban area) during period of May and July 1995. The concentration of the PM 10 in the air is independent to the level of the rainfall. The levels of the PM 10 and the PM 2.5 are lower than the maximum permissible levels set by the US Environmental Protection Agency in July 1997. The element detected using short lived radioactivity measurement in PM 10 and PM 2.5 were Al, Na, V, Mn, Br and Cl. Bromine concentration in both coarse and fine fractions was high, and the enrichment factor for bromine in these fraction was found between 2,000 - 10,000. The elemental concentrations of particulate matter obtained by ICP-MS was found that the Ag, Al, As, Ba, Cd, Co, Cr, Cs, Cu, Fe, In, K, Mg, Mn, Na, Ni, Pb, Rb, V and Zn in samples from Serpong area, were lower than those in samples taken from Jakarta area. The level of Pb concentrations in TSP samples from Serpong and Jakarta area were lower than Pb concentration proposed Indonesian standard of 2 μg/m 3 . The data obtained by INAA no significant different to those obtained by ICP-MS. Therefore comparative data can be obtained by these techniques. (author)

  4. Passive magnetic bearing configurations

    Science.gov (United States)

    Post, Richard F [Walnut Creek, CA

    2011-01-25

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

  5. Biomechanics of coupled motion in the cervical spine during simulated whiplash in patients with pre-existing cervical or lumbar spinal fusion: A Finite Element Study.

    Science.gov (United States)

    Huang, H; Nightingale, R W; Dang, A B C

    2018-01-01

    Loss of motion following spine segment fusion results in increased strain in the adjacent motion segments. However, to date, studies on the biomechanics of the cervical spine have not assessed the role of coupled motions in the lumbar spine. Accordingly, we investigated the biomechanics of the cervical spine following cervical fusion and lumbar fusion during simulated whiplash using a whole-human finite element (FE) model to simulate coupled motions of the spine. A previously validated FE model of the human body in the driver-occupant position was used to investigate cervical hyperextension injury. The cervical spine was subjected to simulated whiplash exposure in accordance with Euro NCAP (the European New Car Assessment Programme) testing using the whole human FE model. The coupled motions between the cervical spine and lumbar spine were assessed by evaluating the biomechanical effects of simulated cervical fusion and lumbar fusion. Peak anterior longitudinal ligament (ALL) strain ranged from 0.106 to 0.382 in a normal spine, and from 0.116 to 0.399 in a fused cervical spine. Strain increased from cranial to caudal levels. The mean strain increase in the motion segment immediately adjacent to the site of fusion from C2-C3 through C5-C6 was 26.1% and 50.8% following single- and two-level cervical fusion, respectively (p = 0.03, unpaired two-way t -test). Peak cervical strains following various lumbar-fusion procedures were 1.0% less than those seen in a healthy spine (p = 0.61, two-way ANOVA). Cervical arthrodesis increases peak ALL strain in the adjacent motion segments. C3-4 experiences greater changes in strain than C6-7. Lumbar fusion did not have a significant effect on cervical spine strain. Cite this article : H. Huang, R. W. Nightingale, A. B. C. Dang. Biomechanics of coupled motion in the cervical spine during simulated whiplash in patients with pre-existing cervical or lumbar spinal fusion: A Finite Element Study. Bone Joint Res 2018;7:28-35. DOI: 10

  6. Modeling of Hybrid Permanent Magnetic-Gas Bearings

    DEFF Research Database (Denmark)

    Morosi, Stefano; Santos, Ilmar

    2009-01-01

    Modern turbomachinery applications require nowadays ever-growing rotational speeds and high degree of reliability. It then becomes natural to focus the attention of the research to contact-free bearings elements. The present alternatives focus on gas lubricated journal bearings or magnetic bearings....... In the present paper, a detailed mathematical modeling of the gas bearing based on the compressible form of the Reynolds equation is presented. Perturbation theory is applied in order to identify the dynamic characteristic of the bearing. Due to the simple design of the magnetic bearings elements - being...... the rotor equilibrium position can be made independent on the rotational speed and applied load; it becomes function of the passive magnetic bearing offset. By adjusting the offset it is possible to significantly influence the dynamic coefficients of the hybrid bearing....

  7. Evaluation of ball and roller bearings restored by grinding

    Science.gov (United States)

    Parker, R. J.; Zaretsky, E. V.; Chen, S. M.

    1976-01-01

    A joint program was undertaken to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. Groups of each of these bearings were visually and dimensionally inspected for suitability for restoration. A total of 250 bearings were restored by grinding. Of this number, 30 bearings from each type were endurance tested to a TBO of 1600 hours. No bearing failures occurred related to the restoration by grinding process. The two bearing failures which occurred were due to defective rolling elements and were typical of those which may occur in new bearings. The restorable component yield to the three groups was in excess of 90 percent.

  8. A three-dimensional cellular automata model coupled with finite element method and thermodynamic database for alloy solidification

    Science.gov (United States)

    Zhao, Y.; Qin, R. S.; Chen, D. F.

    2013-08-01

    A three-dimensional (3D) cellular automata (CA) model has been developed for the simulation of microstructure evolution in alloy solidification. The governing rule for the CA model is associated with the phase transition driving force which is obtained via a thermodynamic database. This determines the migration rate of the non-equilibrium solid-liquid (SL) interface and is calculated according to the local temperature and chemical composition. The curvature of the interface and the anisotropic property of the surface energy are taken into consideration. A 3D finite element (FE) method is applied for the calculation of transient heat and mass transfer. Numerical calculations for the solidification of Fe-1.5 wt% C alloy have been performed. The morphological evolution of dendrites, carbon segregation and temperature distribution in both isothermal and non-isothermal conditions are studied. The parameters affecting the growth of equiaxed and columnar dendrites are discussed. The calculated results are verified using the analytical model and previous experiments. The method provides a sophisticated approach to the solidification of multi-phase and multi-component systems.

  9. Laser ablation-inductively coupled plasma-dynamic reaction cell-mass spectrometry for the multi-element analysis of polymers

    International Nuclear Information System (INIS)

    Resano, M.; Garcia-Ruiz, E.; Vanhaecke, F.

    2005-01-01

    In this work, the potential of laser ablation-inductively coupled plasma-mass spectrometry for the fast analysis of polymers has been explored. Different real-life samples (polyethylene shopping bags, an acrylonitrile butadiene styrene material and various plastic bricks) as well as several reference materials (VDA 001 to 004, Cd in polyethylene) have been selected for the study. Two polyethylene reference materials (ERM-EC 680 and 681), for which a reference or indicative value for the most relevant metals is available, have proved their suitability as standards for calibration. Special attention has been paid to the difficulties expected for the determination of Cr at the μg g -1 level in this kind of materials, due to the interference of ArC + ions on the most abundant isotopes of Cr. The use of ammonia as a reaction gas in a dynamic reaction cell is shown to alleviate this problem, resulting in a limit of detection of 0.15 μg g -1 for this element, while limiting only modestly the possibilities of the technique for simultaneous multi-element analysis. In this regard, As is the analyte most seriously affected by the use of ammonia, and its determination has to be carried out in vented mode, at the expense of measuring time. In all cases studied, accurate results could be obtained for elements ranging in content from the sub-μg g -1 level to tens of thousands of μg g -1 . However, the use of an element of known concentration as internal standard may be needed for materials with a matrix significantly different from that of the standard (polyethylene in this work). Precision ranged between 5% and 10% RSD for elements found at the 10 μg g -1 level or higher, while this value could deteriorate to 20% for analytes found at the sub-μg g -1 level. Overall, the technique evaluated presents many advantages for the fast and accurate multi-element analysis of these materials, avoiding laborious digestion procedures and minimizing the risk of analyte losses due to the

  10. Contact fatigue in rolling-element bearings

    CSIR Research Space (South Africa)

    Fernandes, PJL

    1997-06-01

    Full Text Available to the "cyclone pitting effect" also observed in gear teeth \\[1\\]. The initiation of surface cracks under rollin~sliding contact can be significantly accelerated by the presence of stress concentration sites on the contact surf... formed by rolling and rollin~sliding contact fatigue may progress to form a more severe form of damage known as flaking \\[3\\]. This results in the formation of large, irregular pits which cause rapid deterioration...

  11. Comparison of inductively coupled plasma mass spectrometry with inductively coupled plasma atomic emission spectrometry and instrumental neutron activation analysis for the determination of rare earth elements in Greek bauxites

    International Nuclear Information System (INIS)

    Ochsenkuehn-Petropoulou, Maria; Luck, Joachim

    1991-01-01

    Fore the determination of rare earth elements (REE) in bauxitic materials the techniques of inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES) and instrumental neutron activation analysis (INAA) were compared. In the NIST (National Institute of Standards and Technology) bauxites SRM 697 Dominican, and SRM 69 b Arkansas, the concentration of some REEs were determined. With the reference bauxite BX-N of the ARNT (Association Nationale de la Recherche Technique) the precision and accuracy of ICP-AES for the determination of REEs in bauxites was tested. Furthermore, Greek bauxites of the Parnassos-Giona area were investigated. In a comparison of the three methods it was possible to calculate from the data series the precision of each method, which showed that the tendency found in the deviations for the different REEs is in accordance with published values. Also the limits of detection for REEs in bauxites were calculated and found to be in the same range as those in the literature. (author)

  12. Critical comparison of performances of inductively coupled plasma atomic emission spectrometry and neutron activation analysis for the determination of elements in human lungs

    International Nuclear Information System (INIS)

    Alimonti, A.; Coni, E.; Caroli, S.; Sabbioni, E.; Nicolaou, G.E.; Pietra, R.

    1989-01-01

    A study was carried out to assess the performance of inductively coupled plasma atomic emission spectrometry (ICP-AES) and neutron activation analysis (NAA) techniques for determining reference values for Al, Cd, Cr, Cu, Mg, Mn, V and Zn in human lungs of urban non-smoking subjects. Experimental data were subjected to the usual basic statistical tests to evaluate the respective merits of the two basically different analytical techniques. Both approaches, if used under carefully optimised experimental conditions, can yield reliable results affected only minimally by systematic and random errors. On the other hand, on a more routine basis, particular attention should be paid to elements such as Al, Cd and V which may pose some problems with both techniques. (author)

  13. Curve resolution and figures of merit estimation for determination of trace elements in geological materials by inductively coupled plasma atomic emission spectrometry

    International Nuclear Information System (INIS)

    Lorber, A.; Harel, A.; Goldbart, Z.; Brenner, I.B.

    1987-01-01

    In geochemical analysis using inductively coupled plasma atomic emission spectrometry (ICP-AES), spectral interferences and background enhancement in response to sample concomitants are the main cause of deterioration of the limit of detection (LOD) and inaccuracy of the determination at the trace and minor element levels. In this account, the authors describe the chemometric procedure of curve resolution for compensating for these sources of error. A newly developed method for calculating figures of merit is used to evaluate the correction procedure, test the statistical significance of the determined concentration, and determine LODs for each sample. The technique involves scanning the vicinity of the spectral line of the analyte. With prior knowledge of potential spectral interferences, deconvolution of the overlapped response is possible. Analytical data for a wide range of geological standard reference materials demonstrate the effectiveness of the chemometric techniques. Separation of 0.002 nm spectral coincidence, employing a 0.02 nm resolution spectrometer, is demonstrated

  14. On-line digestion in a focused microwave-assisted oven for elements determination in orange juice by inductively coupled plasma optical emission spectrometry

    Directory of Open Access Journals (Sweden)

    Fili Sabrina P.

    2003-01-01

    Full Text Available A flow injection system coupled to focused microwave-assisted oven was used for on-line orange juice sample digestion for determination of Ca, Cu, Fe, K, Mg, Mn, Na, P, and Zn by inductively coupled plasma optical emission spectrometry. The reactor coil was a PTFE tube (4.0 m long and 1.6 mm i.d. positioned into the commercial glass tube of the focused microwave oven. Aliquots of 500 muL of sample and 1000 muL of reagent (80% v/v HNO3 were mixed in a confluence and carried out to the reactor coil by air carrier. The relative standard deviation for five replicates of sample was lower than 5.0%. Good recoveries varying from 91 to 111% were obtained for added concentrations of the interest elements. The results obtained using the proposed digestion system are in agreement with those obtained for total digestion at the 95% confidence level. With this on-line digestion system was possible to carry out 12 samples h-1, minimizing contamination, saving consumption of samples and reagent and low residue generation.

  15. Coupled Electro-Magneto-Mechanical-Acoustic Analysis Method Developed by Using 2D Finite Element Method for Flat Panel Speaker Driven by Magnetostrictive-Material-Based Actuator

    Science.gov (United States)

    Yoo, Byungjin; Hirata, Katsuhiro; Oonishi, Atsurou

    In this study, a coupled analysis method for flat panel speakers driven by giant magnetostrictive material (GMM) based actuator was developed. The sound field produced by a flat panel speaker that is driven by a GMM actuator depends on the vibration of the flat panel, this vibration is a result of magnetostriction property of the GMM. In this case, to predict the sound pressure level (SPL) in the audio-frequency range, it is necessary to take into account not only the magnetostriction property of the GMM but also the effect of eddy current and the vibration characteristics of the actuator and the flat panel. In this paper, a coupled electromagnetic-structural-acoustic analysis method is presented; this method was developed by using the finite element method (FEM). This analysis method is used to predict the performance of a flat panel speaker in the audio-frequency range. The validity of the analysis method is verified by comparing with the measurement results of a prototype speaker.

  16. Development of a method for fast and automatic radiocarbon measurement of aerosol samples by online coupling of an elemental analyzer with a MICADAS AMS

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, G., E-mail: gary.salazar@dcb.unibe.ch [Department of Chemistry and Biochemistry & Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern (Switzerland); Zhang, Y.L.; Agrios, K. [Department of Chemistry and Biochemistry & Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern (Switzerland); Paul Scherrer Institut (PSI), 5232 Villigen (Switzerland); Szidat, S. [Department of Chemistry and Biochemistry & Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern (Switzerland)

    2015-10-15

    A fast and automatic method for radiocarbon analysis of aerosol samples is presented. This type of analysis requires high number of sample measurements of low carbon masses, but accepts precisions lower than for carbon dating analysis. The method is based on online Trapping CO{sub 2} and coupling an elemental analyzer with a MICADAS AMS by means of a gas interface. It gives similar results to a previously validated reference method for the same set of samples. This method is fast and automatic and typically provides uncertainties of 1.5–5% for representative aerosol samples. It proves to be robust and reliable and allows for overnight and unattended measurements. A constant and cross contamination correction is included, which indicates a constant contamination of 1.4 ± 0.2 μg C with 70 ± 7 pMC and a cross contamination of (0.2 ± 0.1)% from the previous sample. A Real-time online coupling version of the method was also investigated. It shows promising results for standard materials with slightly higher uncertainties than the Trapping online approach.

  17. Simultaneous determination of platinum group elements and rhenium in rock samples using isotope dilution inductively coupled plasma mass spectrometry after cation exchange separation followed by solvent extraction

    International Nuclear Information System (INIS)

    Shinotsuka, Kazunori; Suzuki, Katsuhiko

    2007-01-01

    A simple and precise determination method for platinum group elements (PGEs) and Re in rock samples was developed using isotope dilution coupled with inductively coupled plasma mass spectrometry (ID-ICP-MS). Cation exchange separation was employed for simplicity, because it is applicable to group separation and simultaneous isotopic measurement in contrast with the widely used anion exchange separation which entails separate elution. However, its application to ID-ICP-MS has been limited due to spectral interferences from impurities retained in the PGE fraction even after ion chromatography. To overcome this limitation, solvent extraction using N-benzoyl-N-phenylhydroxylamine (BPHA) in chloroform was successfully applied for further purification. After the examination of optimum experimental parameters in cation exchange separation and solvent extraction using synthetic PGE solution, the established procedure was applied to the determination of PGEs and Re in some geochemical reference materials. The obtained results agreed well with the literature data determined using the different digestion methods (NiS fire assay and the use of a high-pressure asher) within the analytical uncertainties of each other. Significant difference in reproducibility between Ru, Ir, Pt and Os group, and Pd and Re group was observed in the results for BHVO-2 and JA-2. By considering the error factors affecting analytical reproducibility, we concluded that the difference is ascribed to the sample heterogeneity of minor minerals enriched in Ru, Ir, Pt and Os

  18. Analysis of rare earth elements in coal fly ash using laser ablation inductively coupled plasma mass spectrometry and scanning electron microscopy

    Science.gov (United States)

    Thompson, Robert L.; Bank, Tracy; Montross, Scott; Roth, Elliot; Howard, Bret; Verba, Circe; Granite, Evan

    2018-05-01

    Reference standard NIST SRM 1633b and FA 345, a fly ash sample from an eastern U.S. coal power plant, were analyzed to determine and quantify the mineralogical association of rare earth elements (REE). These analyses were completed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and a scanning electron microscope, equipped with an energy-dispersive X-ray spectrometer (SEM-EDS). Internal standardization was avoided by quantifying elemental concentrations by normalizing to 100% oxides. Mineral grains containing elevated REE concentrations were found in diverse chemical environments, but were most commonly found in regions where Al and Si were predominant. Dividing the spot analyses into time segments yielded plots that showed the REE content changing over time as individual mineral grains were being ablated. SEM-EDS images of FA 345 confirmed the trends that were found in the LA-ICP-MS results. Small grains of apatite, monazite, or zircon were frequently observed as free mineral grains or embedded in amorphous aluminosilicate glass and were not associated with ferrous particles. This finding is consistent with previous reports that magnetic enrichment may be an effective way of concentrating non-magnetic REE phases. Furthermore, aggressive mechanical and chemical-based separation schemes will be required to separate and recover REE from aluminosilicate glass.

  19. Upconversion nanoparticle as elemental tag for the determination of alpha-fetoprotein in human serum by inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Liu, Zhengru; Yang, Bin; Chen, Beibei; He, Man; Hu, Bin

    2016-12-19

    Upconversion nanoparticles (UCNPs) have received increasing attention due to their unique optical properties. Recognizing that UCNPs are lanthanide-doped nanoparticles, we incorporated UCNPs into an immunoassay with inductively coupled plasma mass spectrometry (ICP-MS) detection for the determination of specific proteins, e.g., alpha-fetoprotein (AFP). The sensitivity of the assay was enhanced because of the ICP-MS detection of UCNPs that contained large numbers of lanthanide elemental tags. Conjugates of UCNPs and antibodies were prepared and the morphology of the conjugates was characterized by transmission electron microscopy. After a sandwich immunoreaction, the AFP was determined by the ICP-MS analysis of UCNPs. Under the optimized conditions, a limit of detection (3σ) of 0.31 ng mL -1 based on 89 Y signal and 0.22 ng mL -1 based on 174 Yb signal was obtained for AFP, with a dynamic range of 0.5-35 ng mL -1 and a relative standard deviation of 4.8% (c = 5 ng mL -1 , n = 9). The developed method was applied to the determination of AFP in human serum and the recovery for the spiked sample was in the range of 98.6-123%. The proposed method is simple, rapid, selective and sensitive, and has a good tolerance for the complex biological matrix, indicating great potential for the application of UCNP in biological research as an elemental tag.

  20. Spatially and time-resolved element-specific in situ corrosion investigations with an online hyphenated microcapillary flow injection inductively coupled plasma mass spectrometry set-up

    International Nuclear Information System (INIS)

    Homazava, N.; Ulrich, A.; Kraehenbuehl, U.

    2008-01-01

    A novel technique for in situ spatial, time-resolved element-specific investigations of corrosion processes is developed. The technique is based on an online hyphenation of a specially designed microflow-capillary set-up to inductively coupled plasma mass spectrometry (ICP-MS) using flow injection sample introduction. Detailed aspects of the method development, optimization of the sample microflow introduction and flow injection characteristics for the localized corrosion analysis are described. Moreover, specific challenges of the ICP-MS analysis as applied to the analysis of corrosion sample probes, e.g. high matrix load and limited sample volume, are discussed. The efficiency of the developed technique is proved by corrosion susceptibility analysis of a commercial Al alloy. Results of the corrosion experiments of the aluminum alloy AA 6111 are presented to demonstrate the influence of various factors such as exposure time and pH value of the corrosive medium on the element-specific dissolution rates of the alloy. This novel technique provides new aspects in corrosion science and sheds new light on corrosion mechanisms

  1. Direct trace-elemental analysis of urine samples by laser ablation-inductively coupled plasma mass spectrometry after sample deposition on clinical filter papers.

    Science.gov (United States)

    Aramendía, Maite; Rello, Luis; Vanhaecke, Frank; Resano, Martín

    2012-10-16

    Collection of biological fluids on clinical filter papers shows important advantages from a logistic point of view, although analysis of these specimens is far from straightforward. Concerning urine analysis, and particularly when direct trace elemental analysis by laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) is aimed at, several problems arise, such as lack of sensitivity or different distribution of the analytes on the filter paper, rendering obtaining reliable quantitative results quite difficult. In this paper, a novel approach for urine collection is proposed, which circumvents many of these problems. This methodology consists on the use of precut filter paper discs where large amounts of sample can be retained upon a single deposition. This provides higher amounts of the target analytes and, thus, sufficient sensitivity, and allows addition of an adequate internal standard at the clinical lab prior to analysis, therefore making it suitable for a strategy based on unsupervised sample collection and ulterior analysis at referral centers. On the basis of this sampling methodology, an analytical method was developed for the direct determination of several elements in urine (Be, Bi, Cd, Co, Cu, Ni, Sb, Sn, Tl, Pb, and V) at the low μg L(-1) level by means of LA-ICPMS. The method developed provides good results in terms of accuracy and LODs (≤1 μg L(-1) for most of the analytes tested), with a precision in the range of 15%, fit-for-purpose for clinical control analysis.

  2. Elemental bioimaging of nanosilver-coated prostheses using X-ray fluorescence spectroscopy and laser ablation-inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Blaske, Franziska; Reifschneider, Olga; Gosheger, Georg; Wehe, Christoph A; Sperling, Michael; Karst, Uwe; Hauschild, Gregor; Höll, Steffen

    2014-01-07

    The distribution of different chemical elements from a nanosilver-coated bone implant was visualized, combining the benefits of two complementary methods for elemental bioimaging, the nondestructive micro X-ray fluorescence (μ-XRF), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Challenges caused by the physically inhomogeneous materials including bone and soft tissues were addressed by polymer embedding. With the use of μ-XRF, fast sample mapping was achieved obtaining titanium and vanadium signals from the metal implant as well as phosphorus and calcium signals representing hard bone tissue and sulfur distribution representing soft tissues. Only by the use of LA-ICP-MS, the required high sensitivity and low detection limits for the determination of silver were obtained. Metal distribution within the part of cancellous bone was revealed for silver as well as for the implant constituents titanium, vanadium, and aluminum. Furthermore, the detection of coinciding high local zirconium and aluminum signals at the implant surface indicates remaining blasting abrasive from preoperative surface treatment of the nanosilver-coated device.

  3. Determination of major, minor and trace elements in rock samples by laser ablation inductively coupled plasma mass spectrometry: Progress in the utilization of borate glasses as targets

    International Nuclear Information System (INIS)

    Leite, Tacito Dantas F.; Escalfoni, Rainerio; Fonseca, Teresa Cristina O. da; Miekeley, Norbert

    2011-01-01

    The present work is a continuation of a research study performed at our laboratory aiming at the multielement analysis of rock samples (basalts and shale) by inductively coupled plasma mass spectrometry in combination with laser ablation using borate glasses as analytical targets. Argon, nitrogen-argon mixtures and helium were evaluated as cell gases, the latter confirming its better performance. Different operational parameters of the laser, such as gas flow, energy, focus, scanning speed and sampling frequency were optimized. External calibration was made with standards prepared by fusion of geological reference materials (basalts 688 and BCR-2, obsidian SRM 278, and shale SGR-1) of different mass fractions in the meta-tetra borate matrix. Coefficients of determination (R 2 ) were > 0.99 for 30 elements from o total of 40 determined. Method validation was then performed using additional certified reference materials (BHVO-2, BIR-1, SCo-1) produced as borate targets in a similar way. Accuracies were better than 10% for most of the elements studied and analytical precisions, calculated from the residual standard deviations of calibration curves were, typically, between 6% and 10%. Additionally, the semiquantitative TotalQuant (registered) technique was applied, which gave, within the expected uncertainty for this calibration technique, concordant results when compared to the quantitative external calibration procedure. Both methods were then used for the analysis of marine shale samples, which are of great geological interest in petroleum prospecting.

  4. Impact of thermal conductivity models on the coupling of heat transport, oxygen diffusion, and deformation in (U, Pu)O nuclear fuel elements

    Science.gov (United States)

    Mihaila, Bogdan; Stan, Marius; Crapps, Justin; Yun, Di

    2013-02-01

    We study the coupled thermal transport, oxygen diffusion, and thermal expansion in a generic nuclear fuel rod consisting of a (U) fuel pellet separated by a helium gap from zircaloy cladding. Steady-state and time-dependent finite-element simulations with a variety of initial- and boundary-value conditions are used to study the effect of the Pu content, y, and deviation from stoichiometry, x, on the temperature and deformation profiles in this fuel element. We find that the equilibrium radial temperature and deformation profiles are most sensitive to x at small values of y. For larger values of y, the effects of oxygen and Pu content are equally important. Following a change in the heat-generation rate, the centerline temperature, the radial deformation of the fuel pellet, and the centerline deviation from stoichiometry track each other closely in (U,Pu)O, as the characteristic time scales of the heat transport and oxygen diffusion are similar. This result is different from the situation observed in the case of UO fuels.

  5. The influence of precipitation kinetics on trace element partitioning between solid and liquid solutions: A coupled fluid dynamics/thermodynamics framework to predict distribution coefficients

    Science.gov (United States)

    Kavner, A.

    2017-12-01

    In a multicomponent multiphase geochemical system undergoing a chemical reaction such as precipitation and/or dissolution, the partitioning of species between phases is determined by a combination of thermodynamic properties and transport processes. The interpretation of the observed distribution of trace elements requires models integrating coupled chemistry and mechanical transport. Here, a framework is presented that predicts the kinetic effects on the distribution of species between two reacting phases. Based on a perturbation theory combining Navier-Stokes fluid flow and chemical reactivity, the framework predicts rate-dependent partition coefficients in a variety of different systems. We present the theoretical framework, with applications to two systems: 1. species- and isotope-dependent Soret diffusion of species in a multicomponent silicate melt subjected to a temperature gradient, and 2. Elemental partitioning and isotope fractionation during precipitation of a multicomponent solid from a multicomponent liquid phase. Predictions will be compared with results from experimental studies. The approach has applications for understanding chemical exchange in at boundary layers such as the Earth's surface magmatic systems and at the core/mantle boundary.

  6. Microwave dissolution of plant tissue and the subsequent determination of trace lanthanide and actinide elements by inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Alvarado, J.S.; Neal, T.J.; Smith, L.L.; Erickson, M.D.

    1997-01-01

    Recently there has been much concern with the ability of plants to uptake heavy metals from their surroundings. With the development of instrumental techniques with low detection limits such as inductively coupled plasma-mass spectrometry (ICP-MS), attention is shifting toward achieving faster and more elegant ways of oxidizing the organic material inherent in environmental samples. Closed-vessel microwave dissolution was compared with conventional methods for the determination of concentrations of cerium, samarium, europium, terbium, uranium and thorium in a series of samples from the National Institute of Standards and Technology and from fields in Idaho. The ICP-MS technique exhibited detection limits in parts-per-trillion and linear calibration plots over three orders of magnitude for the elements under study. The results obtained by using nitric acid and hydrogen peroxide in a microwave digestion system for the analysis of reference materials showed close agreement with the accepted values. These values were compared with results obtained from dry- and wet-ashing procedures. The findings from an experiment comparing radiometric techniques for the determination of actinide elements to ICP-MS are reported

  7. Modeling of Hydraulic Fracture Propagation at the kISMET Site Using a Fully Coupled 3D Network-Flow and Quasi- Static Discrete Element Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jing [Idaho National Lab. (INL), Idaho Falls, ID (United States); Huang, Hai [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mattson, Earl [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wang, Herb F. [Univ. of Wisconsin, Madison, WI (United States); Haimson, Bezalel C. [Univ. of Wisconsin, Madison, WI (United States); Doe, Thomas W. [Golder Associates Inc., Redmond, VA (United States); Oldenburg, Curtis M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dobson, Patrick F. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-02-01

    Aimed at supporting the design of hydraulic fracturing experiments at the kISMET site, ~1500 m below ground in a deep mine, we performed pre-experimental hydraulic fracturing simulations in order to estimate the breakdown pressure, propagation pressure, fracture geometry, and the magnitude of induced seismicity using a newly developed fully coupled three-dimensional (3D) network flow and quasi-static discrete element model (DEM). The quasi-static DEM model, which is constructed by Delaunay tessellation of the rock volume, considers rock fabric heterogeneities by using the “disordered” DEM mesh and adding random perturbations to the stiffness and tensile/shear strengths of individual DEM elements and the elastic beams between them. A conjugate 3D flow network based on the DEM lattice is constructed to calculate the fluid flow in both the fracture and porous matrix. One distinctive advantage of the model is that fracturing is naturally described by the breakage of elastic beams between DEM elements. It is also extremely convenient to introduce mechanical anisotropy into the model by simply assigning orientation-dependent tensile/shear strengths to the elastic beams. In this paper, the 3D hydraulic fracturing model was verified against the analytic solution for a penny-shaped crack model. We applied the model to simulate fracture propagation from a vertical open borehole based on initial estimates of rock mechanical properties and in-situ stress conditions. The breakdown pressure and propagation pressure are directly obtained from the simulation. In addition, the released elastic strain energies of individual fracturing events were calculated and used as a conservative estimate for the magnitudes of the potential induced seismic activities associated with fracturing. The comparisons between model predictions and experimental results are still ongoing.

  8. Efficient solution of the non-linear Reynolds equation for compressible fluid using the finite element method

    DEFF Research Database (Denmark)

    Larsen, Jon Steffen; Santos, Ilmar

    2015-01-01

    An efficient finite element scheme for solving the non-linear Reynolds equation for compressible fluid coupled to compliant structures is presented. The method is general and fast and can be used in the analysis of airfoil bearings with simplified or complex foil structure models. To illustrate...

  9. A semi-analytical bearing model considering outer race flexibility for model based bearing load monitoring

    Science.gov (United States)

    Kerst, Stijn; Shyrokau, Barys; Holweg, Edward

    2018-05-01

    This paper proposes a novel semi-analytical bearing model addressing flexibility of the bearing outer race structure. It furthermore presents the application of this model in a bearing load condition monitoring approach. The bearing model is developed as current computational low cost bearing models fail to provide an accurate description of the more and more common flexible size and weight optimized bearing designs due to their assumptions of rigidity. In the proposed bearing model raceway flexibility is described by the use of static deformation shapes. The excitation of the deformation shapes is calculated based on the modelled rolling element loads and a Fourier series based compliance approximation. The resulting model is computational low cost and provides an accurate description of the rolling element loads for flexible outer raceway structures. The latter is validated by a simulation-based comparison study with a well-established bearing simulation software tool. An experimental study finally shows the potential of the proposed model in a bearing load monitoring approach.

  10. Teddy Bear Stories

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Caldas-Coulthardt, Carmen

    2014-01-01

    This paper presents a semiotic analysis of a key cultural artefact, the teddy bear. After introducing the iconography of the teddy bear, it analyses different kinds of stories to show how teddy bears are endowed with meaning in everyday life: stories from children's books, reminiscenses by adults...... bears have traditionally centred on interpersonal relations within the nuclear family, but have recently been institutionalized and commercialized....

  11. Multielement analytical procedure coupling INAA, ICP-MS and ICP-AES: Application to the determination of major and trace elements in sediment samples of the Bouregreg river (Morocco)

    International Nuclear Information System (INIS)

    Bounouira, H.; CEA - CNRS/UMR, Centre de Saclay, 91 - Gif sur Yvette; Choukri, A.; Hakam, O.K.; Cherkaoui, R.; Gaudry, A.; Delmas, R.; Mariet, C.; Chakiri, S.

    2008-01-01

    Instrumental neutron activation analysis (INAA), inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were used for the determination of major and trace elements in sediment samples of the Bouregreg river (Morocco). The reliability of the results was checked, by using IAEA Soil-7 certified reference material. Results obtained by the three techniques were compared to control digestions efficiencies. A general good agreement was found between INAA and both ICP-MS and ICP-AES after alkaline fusion (ICPf). The ICP-MS technique used after acid attack (ICPa) was satisfactory for a few elements. A principal component analysis (PCA) has been used for analyzing the variability of concentrations, and defining the most influential sites with respect to the general variation trends. Three groups of elements could be distinguished. For these groups a normalization of concentrations to the central element concentration (that means Mn, Si or Al) is proposed. (author)

  12. Exploiting dynamic reaction cell inductively coupled plasma mass spectrometry (DRC-ICP-MS) for sequential determination of trace elements in blood using a dilute-and-shoot procedure

    International Nuclear Information System (INIS)

    Lemos Batista, Bruno; Lisboa Rodrigues, Jairo; Andrade Nunes, Juliana; Oliveira Souza, Vanessa Cristina de; Barbosa, Fernando

    2009-01-01

    Inductively coupled plasma mass spectrometry with quadrupole (q-ICP-MS) and dynamic reaction cell (DRC-ICP-MS) were evaluated for sequential determination of As, Cd, Co, Cr, Cu, Mn, Pb, Se, Tl, V and Zn in blood. The method requires as little as 100 μL of blood. Prior to analysis, samples (100 μL) were diluted 1:50 in a solution containing 0.01% (v/v) Triton X-100 and 0.5% (v/v) nitric acid. The use of the DRC was only mandatory for Cr, Cu, V and Zn. For the other elements the equipment may be operated in a standard mode (q-ICP-MS). Ammonia was used as reaction gas. Selection of best flow rate of ammonium gas and optimization of the quadrupole dynamic band-pass tuning parameter (RPq) were carried out, using a ovine base blood for Cr and V and a synthetic matrix solution (SMS) for Zn and Cu diluted 1:50 and spiked to contain 1 μg L -1 of each element. Method detection limits (3 s) for 75 As, 114 Cd, 59 Co, 51 Cr, 63 Cu 55 Mn, 208 Pb, 82 Se, 205 Tl, 51 V, and 64 Zn were 14.0, 3.0, 11.0, 7.0, 280, 9.0, 3.0, 264, 0.7, 6.0 and 800 ng L -1 , respectively. Method validation was accomplished by the analysis of blood Reference Materials produced by the L'Institut National de Sante Publique du Quebec (Canada).

  13. Method validation for high resolution sector field inductively coupled plasma mass spectrometry determination of the emerging contaminants in the open ocean: Rare earth elements as a case study

    Science.gov (United States)

    Wysocka, Irena; Vassileva, Emilia

    2017-02-01

    Analytical procedure for the determination of fourteen rare earth elements (REEs) in the seawater samples has been developed and validated. The elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) at ultra-trace level were measured by high resolution sector field inductively coupled plasma mass spectrometry (HR ICP-SFMS) after off-line analytes pre-concentration and matrix separation. The sample pre-treatment was carried out by commercially available automated system seaFAST-pico™, which is a low-pressure ion chromatography technique, based on solid phase extraction principles. Efficient elimination of seawater matrix and up to 50-fold pre-concentration of REEs enabled their accurate and precise quantification at ng L- 1 level. A validation approach in line with the requirements of ISO/IEC 17025 standard and Eurachem guidelines were followed. With this in mind, selectivity, working range, linearity, recovery (from 92% to 102%), repeatability (1%-4%), intermediate precision (2%-6%), limits of detection (0.001-0.08 ng L- 1) were systematically assessed. The total uncertainty associated to each result was estimated and the main sources of uncertainty sorted out. All major contributions to the combined uncertainty of the obtained results were identified and propagated together, following the ISO/GUM guidelines. The relative expanded uncertainty was estimated at range from 10.4% to 11.6% (k = 2). Demonstration of traceability of measurement results was also presented. Due to the low limits of detection, this method enables the determination of ultra-low levels of REEs in the open seawater as well as small variations in their concentrations. The potential of the proposed analytical procedure, based on combination of seaFAST-pico™ for sample preparation and HR ICP-SFMS, was demonstrated by direct analysis of seawater form different regions of the world.

  14. Monitoring of lubrication conditions in journal bearing by acoustic emission

    International Nuclear Information System (INIS)

    Yoon, Dong Jin; Kwon, Oh Yang; Jung, Min Hwa

    1993-01-01

    Systems with journal bearings generally operate in large scale and under severe loading conditions such as steam generator turbines and internal combustion engines, in contrast to the machinery using rolling element bearings. Failure of the bearings in these machinery can result in the system breakdown. To avoid the time consuming repair and considerable economic loss, the detection of incipient failure in journal bearings becomes very important. In this experimental approach, acoustic emission monitoring is employed to the detection of incipient failure caused by intervention of foreign particles most probable in the journal bearing systems. It has been known that the intervention of foreign materials, insufficient lubrication and misassembly etc. are principal factors to cause bearing failure and distress. The experiment was conducted under such designed conditions as inserting alumina particles to the lubrication layer in the simulated journal bearing system. The results showed that acoustic emission could be an effective tool to detect the incipient failure in journal bearings.

  15. Ultra-Sensitive Elemental Analysis Using Plasmas 4.Application of Inductively Coupled Plasma Mass Spectrometry to the Study of Environmental Radioactivity

    Science.gov (United States)

    Yoshida, Satoshi

    Applications of inductively coupled plasma mass spectrometry (ICP-MS) to the determination of long-lived radionuclides in environmental samples were summarized. In order to predict the long-term behavior of the radionuclides, related stable elements were also determined. Compared with radioactivity measurements, the ICP-MS method has advantages in terms of its simple analytical procedures, prompt measurement time, and capability of determining the isotope ratio such as240Pu/239Pu, which can not be separated by radiation. Concentration of U and Th in Japanese surface soils were determined in order to determine the background level of the natural radionuclides. The 235U/238U ratio was successfully used to detect the release of enriched U from reconversion facilities to the environment and to understand the source term. The 240Pu/239Pu ratios in environmental samples varied widely depending on the Pu sources. Applications of ICP-MS to the measurement of I and Tc isotopes were also described. The ratio between radiocesium and stable Cs is useful for judging the equilibrium of deposited radiocesium in a forest ecosystem.

  16. Evaluation of pyrolysis curves for volatile elements in aqueous standards and carbon-containing matrices in electrothermal vaporization inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Silva, A.F. [Delft University of Technology, Faculty of Applied Sciences, DelftChemTech, Julianalaan 136, 2628 BL Delft (Netherlands); Universidade Federal de Santa Catarina, Departamento de Quimica, 88040-900 Florianopolis, SC (Brazil); Welz, B. [Universidade Federal de Santa Catarina, Departamento de Quimica, 88040-900 Florianopolis, SC (Brazil); Loos-Vollebregt, M.T.C. de [Delft University of Technology, Faculty of Applied Sciences, DelftChemTech, Julianalaan 136, 2628 BL Delft (Netherlands)], E-mail: m.t.c.deloos-vollebregt@tudelft.nl

    2008-07-15

    Pyrolysis curves in electrothermal atomic absorption spectrometry (ET AAS) and electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) have been compared for As, Se and Pb in lobster hepatopancreas certified reference material using Pd/Mg as the modifier. The ET AAS pyrolysis curves confirm that the analytes are not lost from the graphite furnace up to a pyrolysis temperature of 800 deg. C. Nevertheless, a downward slope of the pyrolysis curve was observed for these elements in the biological material using ETV-ICP-MS. This could be related to a gain of sensitivity at low pyrolysis temperatures due to the matrix, which can act as carrier and/or promote changes in the plasma ionization equilibrium. Experiments with the addition of ascorbic acid to the aqueous standards confirmed that the higher intensities obtained in ETV-ICP-MS are related to the presence of organic compounds in the slurry. Pyrolysis curves for As, Se and Pb in coal and coal fly ash were also investigated using the same Pd/Mg modifier. Carbon intensities were measured in all samples using different pyrolysis temperatures. It was observed that pyrolysis curves for the three analytes in all slurry samples were similar to the corresponding graphs that show the carbon intensity for the same slurries for pyrolysis temperatures from 200 deg. C up to 1000 deg. C.

  17. Coupling in-situ X-ray micro- and nano-tomography and discrete element method for investigating high temperature sintering of metal and ceramic powders

    Directory of Open Access Journals (Sweden)

    Yan Zilin

    2017-01-01

    Full Text Available The behaviour of various powder systems during high temperature sintering has been investigated by coupling X-ray microtomography and discrete element method (DEM. Both methods are particularly relevant to analyse particle interactions and porosity changes occurring during sintering. Two examples are presented. The first one deals with a copper powder including artificially created pores which sintering has been observed in situ at the European synchrotron and simulated by DEM. 3D images with a resolution of 1.5 μm have been taken at various times of the sintering cycle. The comparison of the real displacement of particle centers with the displacement derived from the mean field assumption demonstrates significant particle rearrangement in some regions of the sample. Although DEM simulation showed less rearrangement, it has been able to accurately predict the densification kinetics. The second example concerns multilayer ceramic capacitors (MLCCs composed of hundreds of alternated metal electrode and ceramic dielectric layers. The observation of Ni-based MLCCs by synchrotron nanotomography at Argon National Laboratory with a spatial resolution between 10 and 50 nm allowed understanding the origin of heterogeneities formed in Ni layers during sintering. DEM simulations confirmed this analysis and provided clues for reducing these defects.

  18. Elemental speciation via high-performance liquid chromatography combined with inductively coupled plasma atomic emission spectroscopic detection: application of a direct injection nebulizer

    International Nuclear Information System (INIS)

    LaFreniere, K.E; Fassel, V.A.; Eckels, D.E.

    1987-01-01

    An evaluation is presented of a direct injection nebulizer (DIN) interfaced to a high-performance liquid chromatograph (HPLC) with inductively coupled plasma atomic emission spectroscopic (ICP-AES) detection for simultaneous multielement speciation. The limits of detection (LODs) obtained with the DIN interface in the HPLC mode were found to be comparable to those obtained by continuous-flow sample introduction into the ICP, or inferior by up to only a factor of 4. In addition, the DIN allowed for the direct injection into the ICP of a variety of common HPLC solvents (up to 100% methanol, acetonitrile, methyl isobutyl ketone, pyridine, and water). The HPLC-DIN-ICP-AES system was compared to other HPLC-atomic spectroscopic detection techniques and was found to offer substantial improvement over the alternative on-line, detection methods in terms of LODs. Representative applications of the HPLC-DIN-ICP-AES system to the elemental speciation of coal process streams, shale oil, solvent refined coal, and crude oil are presented

  19. Microwave-assisted Extraction of Rare Earth Elements from Petroleum Refining Catalysts and Ambient Fine Aerosols Prior to Inductively Coupled Plasma - Mass Spectrometry

    Science.gov (United States)

    Mittlefehldt, David W.; Kulkarni, Pranav; Chellam, Shankar

    2006-01-01

    In the absence of a certified reference material, a robust microwave-assisted acid digestion procedure followed by inductively coupled plasma - mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM2.5). High temperature (200 C), high pressure (200 psig), acid digestion (HNO3, HF, and H3BO3) with 20 minute dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst, and PM2.5. This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb, and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy, and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using 115In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu, and Dy in ambient PM2.5 in an industrial area of Houston, TX.

  20. Microwave-assisted extraction of rare earth elements from petroleum refining catalysts and ambient fine aerosols prior to inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Kulkarni, Pranav; Chellam, Shankararaman; Mittlefehldt, David W.

    2007-01-01

    A robust microwave-assisted acid digestion procedure followed by inductively coupled plasma-mass spectrometry (ICP-MS) was developed to quantify rare earth elements (REEs) in fluidized-bed catalytic cracking (FCC) catalysts and atmospheric fine particulate matter (PM 2.5 ). High temperature (200 deg. C), high pressure (200 psig), acid digestion (HNO 3 , HF and H 3 BO 3 ) with 20 min dwell time effectively solubilized REEs from six fresh catalysts, a spent catalyst and PM 2.5 . This method was also employed to measure 27 non-REEs including Na, Mg, Al, Si, K, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Zr, Mo, Cd, Cs, Ba, Pb and U. Complete extraction of several REEs (Y, La, Ce, Pr, Nd, Tb, Dy and Er) required HF indicating that they were closely associated with the aluminosilicate structure of the zeolite FCC catalysts. Internal standardization using 115 In quantitatively corrected non-spectral interferences in the catalyst digestate matrix. Inter-laboratory comparison using ICP-optical emission spectroscopy (ICP-OES) and instrumental neutron activation analysis (INAA) demonstrated the applicability of the newly developed analytical method for accurate analysis of REEs in FCC catalysts. The method developed for FCC catalysts was also successfully implemented to measure trace to ultra-trace concentrations of La, Ce, Pr, Nd, Sm, Gd, Eu and Dy in ambient PM 2.5 in an industrial area of Houston, TX

  1. Moisture Absorption/Desorption Effects on Flexural Property of Glass-Fiber-Reinforced Polyester Laminates: Three-Point Bending Test and Coupled Hygro-Mechanical Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    Xu Jiang

    2016-08-01

    Full Text Available Influence of moisture absorption/desorption on the flexural properties of Glass-fibre-reinforced polymer (GFRP laminates was experimentally investigated under hot/wet aging environments. To characterize mechanical degradation, three-point bending tests were performed following the ASTM test standard (ASTM D790-10A. The flexural properties of dry (0% Mt/M∞, moisture unsaturated (30% Mt/M∞ and 50% Mt/M∞ and moisture saturated (100% Mt/M∞ specimens at both 20 and 40 °C test temperatures were compared. One cycle of moisture absorption-desorption process was considered in this study to investigate the mechanical degradation scale and the permanent damage of GFRP laminates induced by moisture diffusion. Experimental results confirm that the combination of moisture and temperature effects sincerely deteriorates the flexural properties of GFRP laminates, on both strength and stiffness. Furthermore, the reducing percentage of flexural strength is found much larger than that of E-modulus. Unrecoverable losses of E-modulus (15.0% and flexural strength (16.4% for the GFRP laminates experiencing one cycle of moisture absorption/desorption process are evident at the test temperature of 40 °C, but not for the case of 20 °C test temperature. Moreover, a coupled hygro-mechanical Finite Element (FE model was developed to characterize the mechanical behaviors of GFRP laminates at different moisture absorption/desorption stages, and the modeling method was subsequently validated with flexural test results.

  2. An ultrasound-assisted digestion method for the determination of toxic element concentrations in ash samples by inductively coupled plasma optical emission spectrometry

    International Nuclear Information System (INIS)

    Ilander, Aki; Vaeisaenen, Ari

    2007-01-01

    A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of toxic element concentrations (arsenic, barium, cobalt, copper, lead, nickel, strontium, vanadium and zinc) in ash samples was developed. All the measurements were performed in robust plasma conditions which were tested by measuring the Mg(II) 280.270 nm/Mg(I) 285.213 nm line intensity ratios. The highest line intensity ratios were observed when a nebulizer gas flow of 0.6 L min -1 , auxiliary gas flow of 0.2 L min -1 and plasma power of 1400 W were used for radially viewed plasma. The analysis of SRM 1633b showed that the ultrasound-assisted method developed is highly comparable with the microwave digestion method standardized by the United States Environmental Protection Agency (EPA-3052). The ultrasound-assisted digestion with a digestion solution of aqua regia and hydrofluoric acid (HF) resulted in recovery rates of over 81%. One exception is arsenic which resulted in recoveries of about 60% only; however, it could be digested with good recovery (>90%) using a digestion solution of 5 mL of water and 5 mL of aqua regia. The major advantage of the ultrasound-assisted digestion over microwave digestion is the high treatment rate (30 samples simultaneously with a sonication time of 18 min)

  3. Discussion of the Method to Determine the Ultimate Bearing Capacity of Soil Foundation

    Science.gov (United States)

    Du, Peng; Liu, Xiaoling; Zhang, Yangfu

    2017-12-01

    Combining literature examples, this paper has carried out Contrastive analysis of the theoretical formula method and finite element method about the ultimate bearing capacity of foundation, To verify rationality and superiority of the incremental load method in finite element ABAQUS in solving the bearing capacity of foundation soil. The study can provide certain reference for practical engineering calculation and analysis of foundation bearing capacity.

  4. Berkeley new element program

    International Nuclear Information System (INIS)

    Ghiorso, A.

    1975-09-01

    The work done with element 106 is reviewed, and a new experiment which bears on the properties of the isotope of mass 260 with atomic number 104 is discussed. It is noted that in the case of element 106 a link is demonstrated to the granddaughter as well as the daughter

  5. Nonlinear Dynamical Analysis for a Plain Bearing

    Directory of Open Access Journals (Sweden)

    Ali Belhamra

    2014-03-01

    Full Text Available This paper investigates the nonlinear dynamic behavior for a plain classic bearing (fluid bearing lubricated by a non-Newtonian fluid of a turbo machine rotating with high speed; this type of fluid contains additives viscosity (couple-stress fluid film. The solution of the nonlinear dynamic problem of this type of bearing is determined with a spatial discretisation of the modified Reynolds' equation written in dynamic mode by using the optimized short bearing theory and a temporal discretisation for equations of rotor motion by the help of Euler's explicit diagram. This study analyzes the dynamic behavior of a rotor supported by two couple-stress fluid film journal lubricant enhances the dynamic stability of the rotor-bearing system considerably compared to that obtained when using a traditional Newtonian lubricant. The analysis shows that the dynamic behavior of a shaft which turns with high velocities is strongly nonlinear even for poor eccentricities of unbalance; the presence of parameters of couple stress allows strongly attenuating the will synchrony (unbalance and asynchrony (whipping amplitudes of vibrations of the shaft which supports more severe conditions (large unbalances.

  6. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  7. Permanent magnet design for high-speed superconducting bearings

    Science.gov (United States)

    Hull, John R.; Uherka, Kenneth L.; Abdoud, Robert G.

    1996-01-01

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing.

  8. Permanent magnet design for high-speed superconducting bearings

    International Nuclear Information System (INIS)

    Hull, J.R.; Uherka, K.L.; Abdoud, R.G.

    1996-01-01

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure is disclosed. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing. 9 figs

  9. EcoBears

    DEFF Research Database (Denmark)

    Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

    2015-01-01

    In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

  10. Analytical evaluation of nebulizers for the introduction of acetic acid extracts aiming at the determination of trace elements by inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Gois, Jefferson S. de; Maranhao, Tatiane de A. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-970, Florianopolis, SC (Brazil); Oliveira, Fernando J.S. [Petroleo Brasileiro S.A., Gerencia de Meio Ambiente, Rio de Janeiro, RJ (Brazil); Frescura, Vera L.A.; Curtius, Adilson J. [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-970, Florianopolis, SC (Brazil); Borges, Daniel L.G., E-mail: daniel.borges@ufsc.br [Departamento de Quimica, Universidade Federal de Santa Catarina, 88040-970, Florianopolis, SC (Brazil)

    2012-11-15

    Most of the official procedures aiming at classification of solid waste toxicity take into account metal solubility and bioavailability by means of extraction experiments using acetic acid solutions. Hence, the aim of this work was to investigate and optimize conditions to suppress the effect of acetic acid on the determination of trace elements using inductively coupled plasma mass spectrometry. The performance of four nebulizers (cross-flow (CFN), ultrasonic (USN), Meinhard (MN) and MicroMist (MMN)) were compared as to their efficiency in minimizing spectral and non-spectral effects on the determination of Ag, As, Ba, Cd, Cr, Hg, Pb and Se, with the ultimate goal to analyze acetic acid extracts obtained from solid waste residues. Operating conditions (desolvation temperatures for USN, RF power and nebulizer gas flow rates) were optimized individually for each nebulizer and for all analytes maintained in 0.14 mol L{sup -1} HNO{sub 3} solutions and in solutions prepared with acetic acid and acetic acid + NaOH, adjusted to pH 2.88 and 4.93, respectively. Pronounced non-spectral interferences for {sup 75}As and {sup 82}Se were observed in the presence of acetic acid for CF and MN, although to a less extent also for MMN and USN. Signal increase for blank solutions measured at m/z 208 ({sup 208}Pb) for CFN and MN, 107 ({sup 107}Ag) for USN and MN <