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Sample records for dynamical yield criterion

  1. A Generalized Yield Criterion

    Institute of Scientific and Technical Information of China (English)

    Shijian YUAN; Dazhi XIAO; Zhubin HE

    2004-01-01

    A generalized yield criterion is proposed based on the metal plastic deformation mechanics and the fundamental formula in theory of plasticity. Using the generalized yield criterion, the reason is explained that Mises yield criterion and Tresca yield criterion do not completely match with experimental data. It has been shown that the yield criteria of ductile metals depend not only on the quadratic invariant of the deviatoric stress tensor J2, but also on the cubic invariant of the deviatoric stress tensor J3 and the ratio of the yield stress in pure shear to the yield stress in uniaxial tension k/σs. The reason that Mises yield criterion and Tresca yield criterion are not in good agreement with the experimental data is that the effect of J3 and k/σs is neglected.

  2. A viscoelastic-plastic constitutive model with Mohr-Coulomb yielding criterion for sea ice dynamics

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new viscoelastic-plastic (VEP) constitutive model for sea ice dynamics was developed based on continuum mechanics. This model consists of four components: Kelvin-Vogit viscoelastic model, Mohr-Coulomb yielding criterion, associated normality flow rule for plastic rehololgy, and hydrostatic pressure. The numerical simulations for ice motion in an idealized rectangular basin were made using smoothed particle hydrodynamics (SPH) method, and compared with the analytical solution as well as those based on the modified viscous plastic(VP) model and static ice jam theory. These simulations show that the new VEP modelcan simulate ice dynamics accurately. The new constitutive model was further applied to simulate ice dynamics of the Bohai Sea and compared with the traditional VP, and modified VP models. The results of the VEP model are compared better with the satellite remote images, and the simulated ice conditions in the JZ20-2 oil platform area were more reasonable.

  3. A study of the energy yield criterion of geomaterials

    Institute of Scientific and Technical Information of China (English)

    Gao Hong; Zheng Yingren; Feng Xiating; Zeng Jing

    2010-01-01

    The study results of the internal friction character of geomaterials conclude that the internal friction exists in mechanical elements all the time having a direction opposite to the shear stress,and the deformation failure mechanism of geomaterials greatly differs from that of metals.For metals,the failure results from shear stresses make the crystal structure slip;whereas for geomaterials,owing to its attribute of granular structures,their deformation follows the friction law,it is the co-action of shear stresses and perpendicular stresses that makes grains overcome the frictions between them,thus leading to the final failure of relative sliding.Therefore,on the basis of the cognition above,a triple shear energy criterion is proposed.Its corresponding Drucker-Prager criterion for geomaterials is also given.The new criterion can be rewritten to the Mohr-Coulomb criterion by neglecting the effect of the intermediate principal stress,and to the Mises criterion by not taking the internal friction angle into consideration.Then the studies of yield criteria commonly used are conducted systematical]y from the points of stress,strain and energy of geomaterials.The results show that no matter which expression form of stress,strain or energy is used for the yield criterion,the essence is the same and the triple shear energy yield criterion is the unified criterion of materials.Finally,the experimental verification is conducted in connection with the practical application of the triple shear energy yield criterion in an engineering project,and the calculation result shows that the Mohr-Coulomb criterion which only takes the single shear surface into account is more conservative than the energy criterion that does consider the effect of triple shear surfaces.

  4. Derivation of Plastic Work Rate Done per Unit Volume for Mean Yield Criterion and Its Application

    Institute of Scientific and Technical Information of China (English)

    Dewen ZHAO; Yingjie XIE; Xiaowen WANG; Xianghua LIU

    2005-01-01

    In Haigh Westergaard stress space linear combination of twin shear stress and Tresca yield functions is called the mean yield (MY) criterion. The mathematical relationship of the criterion and its plastic work rate done per unit volume were derived. A generalized worked example of slab forging was analyzed by the criterion and its corresponding plastic work rate done per unit volume. Then, the precision of the solution was compared with those by Mises and Twin shear stress yield criterions, respectively. It turned out that the calculated results by MY criterion were in good agreement with those by Mises criterion.

  5. Equal perimeter yield criterion and its specific plastic work rate: Development, validation and application

    Institute of Scientific and Technical Information of China (English)

    章顺虎; 赵德文; 陈晓东

    2015-01-01

    In order to overcome the nonlinearity of Mises criterion, a new linear yield criterion with a dodecagon shape of the same perimeter as Mises criterion was derived by means of geometrical analysis. Its specific plastic work rate expressed as a linear function of the yield stress, the maximum and minimum strains was also deduced and compared with that of Mises criterion. The physical meaning of the proposed yield criterion is that yielding of materials begins when the shear yield stress τs reaches the magnitude of 0.594σs. By introducing the Lode parameter, validation of evolution expressions of the proposed yield criterion with those based on Tresca, Mises and TSS criteria as well as available classical yield experimental results of various metals shows that the present results intersect with Mises results and coincide well with experimental data. Moreover, further application to the limit analysis of circle plate as an example is performed to demonstrate the effectiveness of the proposed yield criterion, and the subsequent comparison of limit loads with the Tresca analytical solutions and Mises numerical results shows that the present results are higher than the Tresca analytical results, and are in good agreement with the Mises numerical results.

  6. A Gurson-type criterion for porous ductile solids containing arbitrary ellipsoidal voids—II: Determination of yield criterion parameters

    Science.gov (United States)

    Madou, Komlanvi; Leblond, Jean-Baptiste

    2012-05-01

    The aim of this paper is to fully determine the parameters of the approximate homogenized yield criterion for porous ductile solids containing arbitrary ellipsoidal cavities proposed in Part I. This is done through improvements of the limit-analysis of some representative hollow cell presented there. The improvements are of two kinds. For hydrostatic loadings, the limit-analysis is refined by performing micromechanical finite element computations in a number of significant cases, so as to replace Leblond and Gologanu (2008)'s trial velocity field representing the expansion of the void by the exact, numerically determined one. For deviatoric loadings, limit-analysis is dropped and direct use is made of some general rigorous results for nonlinear composites derived by Ponte-Castaneda (1991), Willis (1991) and Michel and Suquet (1992) using the earlier work of Willis (1977) and the concept of "linear comparison material". This hybrid approach is thought to lead to the best possible expressions of the yield criterion parameters. The criterion proposed reduces to (variants of) classical approximate criteria proposed by Gurson (1977) and Gologanu et al. (1993, 1994, 1997) in the specific cases of spherical or spheroidal, prolate or oblate cavities. An overview of the validation of this criterion through micromechanical finite element computations is finally presented.

  7. A yield criterion based on mean shear stress

    NARCIS (Netherlands)

    Emmens, W.C.; Boogaard, van den A.H.

    2014-01-01

    This work investigates the relation between shear stress and plastic yield considering that a crystal can only deform in a limited set of directions. The shear stress in arbitrary directions is mapped for some cases showing relevant differences. Yield loci based on mean shear stress are con- structe

  8. Suboptimal Criterion Learning in Static and Dynamic Environments.

    Science.gov (United States)

    Norton, Elyse H; Fleming, Stephen M; Daw, Nathaniel D; Landy, Michael S

    2017-01-01

    Humans often make decisions based on uncertain sensory information. Signal detection theory (SDT) describes detection and discrimination decisions as a comparison of stimulus "strength" to a fixed decision criterion. However, recent research suggests that current responses depend on the recent history of stimuli and previous responses, suggesting that the decision criterion is updated trial-by-trial. The mechanisms underpinning criterion setting remain unknown. Here, we examine how observers learn to set a decision criterion in an orientation-discrimination task under both static and dynamic conditions. To investigate mechanisms underlying trial-by-trial criterion placement, we introduce a novel task in which participants explicitly set the criterion, and compare it to a more traditional discrimination task, allowing us to model this explicit indication of criterion dynamics. In each task, stimuli were ellipses with principal orientations drawn from two categories: Gaussian distributions with different means and equal variance. In the covert-criterion task, observers categorized a displayed ellipse. In the overt-criterion task, observers adjusted the orientation of a line that served as the discrimination criterion for a subsequently presented ellipse. We compared performance to the ideal Bayesian learner and several suboptimal models that varied in both computational and memory demands. Under static and dynamic conditions, we found that, in both tasks, observers used suboptimal learning rules. In most conditions, a model in which the recent history of past samples determines a belief about category means fit the data best for most observers and on average. Our results reveal dynamic adjustment of discrimination criterion, even after prolonged training, and indicate how decision criteria are updated over time.

  9. Slope Safety Factor Calculations With Non-Linear Yield Criterion Using Finite Elements

    DEFF Research Database (Denmark)

    Clausen, Johan; Damkilde, Lars

    2006-01-01

    The factor of safety for a slope is calculated with the finite element method using a non-linear yield criterion of the Hoek-Brown type. The parameters of the Hoek-Brown criterion are found from triaxial test data. Parameters of the linear Mohr-Coulomb criterion are calibrated to the same triaxial...... are carried out at much higher stress levels than present in a slope failure, this leads to the conclusion that the use of the non-linear criterion leads to a safer slope design...

  10. Slope Safety Factor Calculations With Non-Linear Yield Criterion Using Finite Elements

    DEFF Research Database (Denmark)

    Clausen, Johan Christian; Damkilde, Lars

    2006-01-01

    The factor of safety for a slope is calculated with the finite element method using a non-linear yield criterion of the Hoek-Brown type. The parameters of the Hoek-Brown criterion are found from triaxial test data. Parameters of the linear Mohr-Coulomb criterion are calibrated to the same triaxial...... are carried out at much higher stress levels than present in a slope failure, this leads to the conclusion that the use of the non-linear criterion leads to a safer slope design....

  11. Slope Safety Factor Calculations With Non-Linear Yield Criterion Using Finite Elements

    DEFF Research Database (Denmark)

    Clausen, Johan Christian; Damkilde, Lars

    2006-01-01

    The factor of safety for a slope is calculated with the finite element method using a non-linear yield criterion of the Hoek-Brown type. The parameters of the Hoek-Brown criterion are found from triaxial test data. Parameters of the linear Mohr-Coulomb criterion are calibrated to the same triaxial...... are carried out at much higher stress levels than present in a slope failure, this leads to the conclusion that the use of the non-linear criterion leads to a safer slope design....

  12. Slope Safety Factor Calculations With Non-Linear Yield Criterion Using Finite Elements

    DEFF Research Database (Denmark)

    Clausen, Johan; Damkilde, Lars

    2006-01-01

    The factor of safety for a slope is calculated with the finite element method using a non-linear yield criterion of the Hoek-Brown type. The parameters of the Hoek-Brown criterion are found from triaxial test data. Parameters of the linear Mohr-Coulomb criterion are calibrated to the same triaxial...... are carried out at much higher stress levels than present in a slope failure, this leads to the conclusion that the use of the non-linear criterion leads to a safer slope design...

  13. A new elliptic-parabolic yield surface model revised by an adaptive criterion for granular soils

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    An adaptive criterion for shear yielding as well as shear failure of soils is proposed in this paper to address the fact that most criteria,including the Mohr-Coulomb criterion,the Lade criterion and the Matsuoka-Nakai criterion,cannot agree well with the experimental results when the value of the intermediate principal stress parameter is too big.The new criterion can adjust an adaptive parameter based on the experimental results in order to make the theoretical calculations fit the test results more accurately.The original elliptic-parabolic yield surface model can capture both soil contraction and dilation behaviors.However,it normally over-predicts the soil strength due to its application of the Extended Mises criterion.A new elliptic-parabolic yield surface mode is presented in this paper,which introduces the adaptive criterion in three-dimensional principal stress space.The new model can well model the stress-strain behavior of soils under general stress conditions.Compared to the original model which can only simulate soil behavior under triaxial compression conditions,the new model can simulate soil behaviors under both triaxial compression conditions and general stress conditions.

  14. Application of geometric midline yield criterion to analysis of three-dimensional forging

    Institute of Scientific and Technical Information of China (English)

    ZHAO De-wen; WANG Gen-ji; LIU Xiang-hua; WANG Guo-dong

    2008-01-01

    A kinematically admissible continuous velocity field was proposed for the analysis of three-dimensional forging. The linear yield criterion expressed by geometric midline of error triangle between Tresca and Twin shear stress yield loci on the π-plane, called GM yield criterion for short, was firstly applied to analysis of the velocity field for the forging. The analytical solution of the forging force with the effects of external zone and bulging parameter is obtained by strain rate inner product. Compression tests of pure lead are performed to compare the calculated results with the measured ones. The results show that the calculated total pressures are higher than the measured ones whilst the relative error is no more than 9.5%. It is implied that the velocity field is reasonable and the geometric midline yield criterion is available. The solution is still an upper-bound one.

  15. Deduction of plastic work rate per unit volume for unified yield criterion and its application

    Institute of Scientific and Technical Information of China (English)

    ZHAO De-wen; LI Jing; LIU Xiang-hua; WANG Guo-dong

    2009-01-01

    A unified linear expression of plastic work rate per unit volume is deduced from the unified linear yield criterion and the associated flow rule. The expression is suitable for various linear yield loci in the error triangle between Tresca's and twin shear stress yield loci on the π-plane. It exhibits generalization in which the different value of criterion parameter b corresponds to a specific linear formula of plastic work rate per unit volume. Finally, with the unified linear expression of plastic work rate and upper-bound parallel velocity field the strip forging without bulge is successfully analyzed and an analytical result is also obtained. The comparison with traditional solutions shows that when b=1/(1+(√3)) the result is the same as the upper bound result by Mises' yield criterion, and it also is identical to that by slab method with m=1, σ0=0.

  16. Three-Dimensional Analysis of Rolling by Twin Shear Stress Yield Criterion

    Institute of Scientific and Technical Information of China (English)

    ZHAO De-wen; XIE Ying-jie; LIU Xiang-hua; WANG Guo-dong

    2006-01-01

    Using the twin shear stress yield criterion, the surface integral of the co-line vectors, and the integration depending on upper limit, Kobayashi's three-dimensional velocity field of rolling was analyzed and an analytical expression of rolling torque and single force was obtained. Through redoing the same experiment of rolling pure lead as Sims, the calculated results by the above expression were compared with those of Kobayashi and Sims formulae. The results show that the twin shear stress yield criterion is available for rolling analysis and the calculated results by the new formula are a little higher than those by Kobayashi and Sims ones if the reduction ratio is less than 30%.

  17. Earing Prediction in Cup Drawing using the BBC2008 Yield Criterion

    Science.gov (United States)

    Vrh, Marko; Halilovič, Miroslav; Starman, Bojan; Štok, Boris; Comsa, Dan-Sorin; Banabic, Dorel

    2011-08-01

    The paper deals with constitutive modelling of highly anisotropic sheet metals. It presents FEM based earing predictions in cup drawing simulation of highly anisotropic aluminium alloys where more than four ears occur. For that purpose the BBC2008 yield criterion, which is a plane-stress yield criterion formulated in the form of a finite series, is used. Thus defined criterion can be expanded to retain more or less terms, depending on the amount of given experimental data. In order to use the model in sheet metal forming simulations we have implemented it in a general purpose finite element code ABAQUS/Explicit via VUMAT subroutine, considering alternatively eight or sixteen parameters (8p and 16p version). For the integration of the constitutive model the explicit NICE (Next Increment Corrects Error) integration scheme has been used. Due to the scheme effectiveness the CPU time consumption for a simulation is comparable to the time consumption of built-in constitutive models. Two aluminium alloys, namely AA5042-H2 and AA2090-T3, have been used for a validation of the model. For both alloys the parameters of the BBC2008 model have been identified with a developed numerical procedure, based on a minimization of the developed cost function. For both materials, the predictions of the BBC2008 model prove to be in very good agreement with the experimental results. The flexibility and the accuracy of the model together with the identification and integration procedure guarantee the applicability of the BBC2008 yield criterion in industrial applications.

  18. The quartic piecewise-linear criterion for the multiaxial yield behavior of human trabecular bone.

    Science.gov (United States)

    Sanyal, Arnav; Scheffelin, Joanna; Keaveny, Tony M

    2015-01-01

    Prior multiaxial strength studies on trabecular bone have either not addressed large variations in bone volume fraction and microarchitecture, or have not addressed the full range of multiaxial stress states. Addressing these limitations, we utilized micro-computed tomography (lCT) based nonlinear finite element analysis to investigate the complete 3D multiaxial failure behavior of ten specimens (5mm cube) of human trabecular bone, taken from three anatomic sites and spanning a wide range of bone volume fraction (0.09–0.36),mechanical anisotropy (range of E3/E1¼3.0–12.0), and microarchitecture. We found that most of the observed variation in multiaxial strength behavior could be accounted for by normalizing the multiaxial strength by specimen-specific values of uniaxial strength (tension,compression in the longitudinal and transverse directions). Scatter between specimens was reduced further when the normalized multiaxial strength was described in strain space.The resulting multiaxial failure envelope in this normalized-strain space had a rectangular boxlike shape for normal–normal loading and either a rhomboidal box like shape or a triangular shape for normal-shear loading, depending on the loading direction. The finite element data were well described by a single quartic yield criterion in the 6D normalized strain space combined with a piecewise linear yield criterion in two planes for normalshear loading (mean error SD: 4.660.8% for the finite element data versus the criterion).This multiaxial yield criterion in normalized-strain space can be used to describe the complete 3D multiaxial failure behavior of human trabecular bone across a wide range of bone volume fraction, mechanical anisotropy, and microarchitecture.

  19. A Dynamic Stability Criterion for Ice Shelves and Tidewater Glaciers

    Science.gov (United States)

    Bassis, J. N.; Fricker, H. A.; Minster, J.

    2006-12-01

    The collapse of the Antarctic ice shelves could have dramatic consequences for the mass balance of the Antarctic ice sheet and, as a result, sea level rise. It is therefore imperative to improve our knowledge of the mechanisms that lead to ice shelf retreat. The mechanism that has the potential to remove the largest amounts of mass rapidly is iceberg calving. However, the processes and mechanisms that lead to iceberg calving are still poorly understood. Motivated by the complexity of the short-time scale behavior of ice fracture we seek a dynamic stability criterion that predicts the onset of ice shelf retreat based on dimensional analysis. In our approach, rather than attempt to model the initiation and propagation of individual fractures, we look for a non-dimensional number that describes the overall ice shelf stability. We also make the assumption that the same criterion, valid for ice shelves, also applies to tidewater glaciers. This enables us to test our criterion against a larger set of ice shelves and calving glaciers. Our analysis predicts that retreat will occur when a non-dimensional number that we call the "terminus stability number", decreases below a critical value. We show that this criterion is valid for calving glaciers in Alaska, for several glaciers around Greenland as well as for three Antarctic ice shelves. This stability analysis has much in common with classic hydrodynamic stability theory, where the onset of instability is related to non-dimensional numbers that are largely independent of geometry or other situation specific variables.

  20. Neutron yield and Lawson criterion for plasma with inertial electrostatic confinement

    Science.gov (United States)

    Gus'kov, S. Yu; Kurilenkov, Yu K.

    2016-11-01

    The physics of plasma formation is discussed in the systems with inertial electrostatic confinement (IEC) during the convergent to the axis of cylindrical geometry of the ion flow accelerated periodically in the field of virtual cathode, which is formed by the injected electrons. The ranges of plasma parameters and the resulting neutron yield are determined for different modes of ion flux formation. The requirements are formulated to the technical parameters of the system with IEC to create both a powerful neutron source with a rate of generation exceeding 1010-1012 particles/s and to achieve a positive energy output (analogue of Lawson criterion).

  1. Sufficient Conditions for Dynamical Output Feedback Stabilization Via the Circle Criterion

    OpenAIRE

    2003-01-01

    This paper suggests sufficient conditions for asymptotically stable dynamical output feedback controller design based on the circle criterion. It is shown that a dynamic output feedback stabilization problem with impending problems of finite escape time, previously attacked by observer-based design, can be successfully solved using circle criterion design. Stability of the closed-loop system is global and robust to parameter uncertainty.

  2. Experimental and finite element analysis of fracture criterion in general yielding fracture mechanics

    Indian Academy of Sciences (India)

    D M Kulkarni; Ravi Prakash; A N Kumar

    2002-12-01

    Efforts made over the last three decades to understand the fracture behaviour of structural materials in elastic and elasto-plastic fracture mechanics are numerous, whereas investigations related to fracture behaviour of materials in thin sheets or general yielding fracture regimes are limited in number. Engineering simulative tests are being used to characterize formability and drawability of sheet metals. However, these tests do not assure consistency in quality of sheet metal products. The prevention of failure in stressed structural components currently requires fracture mechanics based design parameters like critical load, critical crack-tip opening displacement or fracture toughness. The present attempt would aim to fulfill this gap and generate more information thereby increased understanding on fracture behaviour of sheet metals. In the present investigation, using a recently developed technique for determining fracture criteria in sheet metals, results are generated on critical CTOD and fracture toughness. Finite element analysis was performed to support the results on various fracture parameters. The differences are within 1 to 4%. At the end it is concluded that magnitude of critical CTOD and/or critical load can be used as a fracture criterion for thin sheets.

  3. Chirikov criterion of resonance overlapping for the model of molecular dynamics

    CERN Document Server

    Guzev, M A

    2012-01-01

    The chaotic dynamics in a cell of particles' chain interacting by means of Lennard-Jones potential is considered. Chirikov criterion of resonance over- lapping is used as the condition of chaos. The asymptotic representation for this function at low and high energies is obtained for the function corresponding to the criterion.

  4. STUDY OF CARRYING CAPACITY OF A CORRUGATED METAL CONSTRUCTION BY CRITERION OF YIELD HINGE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Y. Y. Luchko

    2015-10-01

    Full Text Available Purpose. This research is aimed to: 1 calculation of equivalent forces caused by rolling stock in winter and summer seasons at different parameters of the irregularities of railway track; 2 research of bearing capacity of corrugated metal constructions (CMC in terms of development of plastic hinge in the top of the metal pipe due to irreversible residual deformation of the vertical and horizontal diameters of the pipe. Methodology. The calculation of equivalent forces is carried out according to the method of calculating the railway track on strength and stability. Further a mathematical algorithm was developed in the software environment of Mathcad 14, with which the calculations were made about the formation of a plastic hinge at the top of the pipe for different values of the irregularities of the railway track and the degree of compaction of soil backfill. In these studies, the calculations were carried out at the design value of the compaction degree of soil backfill and magnitude of dynamic loading on railway rolling stock. Findings. Analysis of multivariate calculations of testing the condition of occurrence of plastic hinge at the top of the pipe arch has revealed that the first plastic hinge, which occurs in the set of CMC is revealed only when there is a simultaneous unfavorable influence of two factors (causes. These are the factors: the assumption of the development of the track irregularities out of the allowable values without the implementation of measures to eliminate or limit the speed of trains (the first cause; reduction of compaction of soil backfill below the 90 % (the second cause. In case of absence of one of the causes the origin of the plastic hinge will not happen. Originality. It was the first time, when the bearing capacity of corrugated metal construction with large diameter (more than 6 m with account of factors complex: the degree of compaction of soil backfill, the magnitude of the dynamic loads from rolling stock

  5. Closed-form dynamic stability criterion for elastic-plastic structures under near-fault ground motions

    Directory of Open Access Journals (Sweden)

    Kotaro eKojima

    2016-03-01

    Full Text Available A dynamic stability criterion for elastic-plastic structures under near-fault ground motions is derived in closed-form. A negative post-yield stiffness is treated in order to consider the P-delta effect. The double impulse is used as a substitute of the fling-step near-fault ground motion. Since only the free-vibration appears under such double impulse, the energy approach plays a critical role in the derivation of the closed-form solution of a complicated elastic-plastic response of structures with the P-delta effect. It is remarkable that no iteration is needed in the derivation of the closed-form dynamic stability criterion on the critical elastic-plastic response. It is shown via the closed-form expression that several patterns of unstable behaviors exist depending on the ratio of the input level of the double impulse to the structural strength and on the ratio of the negative post-yield stiffness to the initial elastic stiffness. The validity of the proposed dynamic stability criterion is investigated by the numerical response analysis for structures under double impulses with stable or unstable parameters. Furthermore the reliability of the proposed theory is tested through the comparison with the response analysis to the corresponding one-cycle sinusoidal input as a representative of the fling-step near-fault ground motion. The applicability of the proposed theory to actual recorded pulse-type ground motions is also discussed.

  6. Synchronization criterion for Lur'e type complex dynamical networks with time-varying delay

    Energy Technology Data Exchange (ETDEWEB)

    Ji, D.H., E-mail: captainzone@gmail.co [Mobile Communication Division, Digital Media and Communications, Samsung Electronics, Co. Ltd., 461-2 Maetan-Dong, Suwon 443-803 (Korea, Republic of); Park, Ju H., E-mail: jessie@ynu.ac.k [Nonlinear Dynamics Group, Department of Electrical Engineering, Yeungnam University, 214-1 Dae-Dong, Kyongsan 712-749 (Korea, Republic of); Yoo, W.J.; Won, S.C. [Department of Electronic and Electrical Engineering, Pohang University of Science and Technology, San 31 Hyoja-Dong, Pohang 790-784 (Korea, Republic of); Lee, S.M. [School of Electronics Engineering, Daegu University, Kyongsan (Korea, Republic of)

    2010-02-22

    In this Letter, the synchronization problem for a class of complex dynamical networks in which every identical node is a Lur'e system with time-varying delay is considered. A delay-dependent synchronization criterion is derived for the synchronization of complex dynamical network that represented by Lur'e system with sector restricted nonlinearities. The derived criterion is a sufficient condition for absolute stability of error dynamics between the each nodes and the isolated node. Using a convex representation of the nonlinearity for error dynamics, the stability condition based on the discretized Lyapunov-Krasovskii functional is obtained via LMI formulation. The proposed delay-dependent synchronization criterion is less conservative than the existing ones. The effectiveness of our work is verified through numerical examples.

  7. Systemic risk in dynamical networks with stochastic failure criterion

    Science.gov (United States)

    Podobnik, B.; Horvatic, D.; Bertella, M. A.; Feng, L.; Huang, X.; Li, B.

    2014-06-01

    Complex non-linear interactions between banks and assets we model by two time-dependent Erdős-Renyi network models where each node, representing a bank, can invest either to a single asset (model I) or multiple assets (model II). We use a dynamical network approach to evaluate the collective financial failure —systemic risk— quantified by the fraction of active nodes. The systemic risk can be calculated over any future time period, divided into sub-periods, where within each sub-period banks may contiguously fail due to links to either i) assets or ii) other banks, controlled by two parameters, probability of internal failure p and threshold Th (“solvency” parameter). The systemic risk decreases with the average network degree faster when all assets are equally distributed across banks than if assets are randomly distributed. The more inactive banks each bank can sustain (smaller Th), the smaller the systemic risk —for some Th values in I we report a discontinuity in systemic risk. When contiguous spreading becomes stochastic ii) controlled by probability p2 —a condition for the bank to be solvent (active) is stochastic— the systemic risk decreases with decreasing p2. We analyse the asset allocation for the U.S. banks.

  8. Optimal Dynamic Portfolio with Mean-CVaR Criterion

    Directory of Open Access Journals (Sweden)

    Mingxin Xu

    2013-11-01

    Full Text Available Value-at-risk (VaR and conditional value-at-risk (CVaR are popular risk measures from academic, industrial and regulatory perspectives. The problem of minimizing CVaR is theoretically known to be of a Neyman–Pearson type binary solution. We add a constraint on expected return to investigate the mean-CVaR portfolio selection problem in a dynamic setting: the investor is faced with a Markowitz type of risk reward problem at the final horizon, where variance as a measure of risk is replaced by CVaR. Based on the complete market assumption, we give an analytical solution in general. The novelty of our solution is that it is no longer the Neyman–Pearson type, in which the final optimal portfolio takes only two values. Instead, in the case in which the portfolio value is required to be bounded from above, the optimal solution takes three values; while in the case in which there is no upper bound, the optimal investment portfolio does not exist, though a three-level portfolio still provides a sub-optimal solution.

  9. Temperature-dependent yield criterion for high strength steel sheets under warm-forming conditions

    Directory of Open Access Journals (Sweden)

    Cai Zhengyang

    2015-01-01

    Full Text Available In this paper, uniaxial and biaxial tensile tests with cruciform specimens were conducted to investigate the deformation behaviour of dual phase steel sheet with a tensile strength of 590 MPa (DP590 under evaluated warm-forming temperatures (20–190 ∘C. Detailed analyses were then carried out to obtain the corresponding experimental yield loci. For the purpose of describing the temperature-dependent yield behaviour of DP590 appropriately, the Yld2000–2d yield function with temperature-dependent exponent was proposed. The identification procedures of the introduced parameters were then proposed based on Levenberg-Marquardt optimization algorithm. Afterwards, the proposed model was implemented into ABAQUS as user subroutine VUMAT with NICE (Next Increment Corrects Error explicit integration scheme. The numerical simulations of biaxial tensile tests were then conducted to confirm the validity of the proposed model. It could be concluded that the flexibility and accuracy of the proposed model guarantee the applicability in warm-forming applications.

  10. Wheat yield dynamics: a structural econometric analysis.

    Science.gov (United States)

    Sahin, Afsin; Akdi, Yilmaz; Arslan, Fahrettin

    2007-10-15

    In this study we initially have tried to explore the wheat situation in Turkey, which has a small-open economy and in the member countries of European Union (EU). We have observed that increasing the wheat yield is fundamental to obtain comparative advantage among countries by depressing domestic prices. Also the changing structure of supporting schemes in Turkey makes it necessary to increase its wheat yield level. For this purpose, we have used available data to determine the dynamics of wheat yield by Ordinary Least Square Regression methods. In order to find out whether there is a linear relationship among these series we have checked each series whether they are integrated at the same order or not. Consequently, we have pointed out that fertilizer usage and precipitation level are substantial inputs for producing high wheat yield. Furthermore, in respect for our model, fertilizer usage affects wheat yield more than precipitation level.

  11. Dynamic Control of Response Criterion in Premotor Cortex during Perceptual Detection under Temporal Uncertainty.

    Science.gov (United States)

    Carnevale, Federico; de Lafuente, Victor; Romo, Ranulfo; Barak, Omri; Parga, Néstor

    2015-05-20

    Under uncertainty, the brain uses previous knowledge to transform sensory inputs into the percepts on which decisions are based. When the uncertainty lies in the timing of sensory evidence, however, the mechanism underlying the use of previously acquired temporal information remains unknown. We study this issue in monkeys performing a detection task with variable stimulation times. We use the neural correlates of false alarms to infer the subject's response criterion and find that it modulates over the course of a trial. Analysis of premotor cortex activity shows that this modulation is represented by the dynamics of population responses. A trained recurrent network model reproduces the experimental findings and demonstrates a neural mechanism to benefit from temporal expectations in perceptual detection. Previous knowledge about the probability of stimulation over time can be intrinsically encoded in the neural population dynamics, allowing a flexible control of the response criterion over time.

  12. Partial dynamical symmetry as a selection criterion for many-body interactions

    CERN Document Server

    Leviatan, A; Van Isacker, P

    2013-01-01

    We propose the use of partial dynamical symmetry (PDS) as a selection criterion for higher-order terms in situations when a prescribed symmetry is obeyed by some states and is strongly broken in others. The procedure is demonstrated in a first systematic classification of many-body interactions with SU(3) PDS that can improve the description of deformed nuclei. As an example, the triaxial features of the nucleus 156Gd are analyzed.

  13. Minimum description length criterion based decision tree dynamic pruning method in speech recognition

    Institute of Scientific and Technical Information of China (English)

    XU Xianghua; HE lin

    2006-01-01

    In phonetic decision tree based state tying, decision trees with varying leaf nodes denote models with different complexity. By studying the influence of model complexity on system performance and speaker adaptation, a decision tree dynamic pruning method based on Minimum Description Length (MDL) criterion is presented. In the method, a well-trained,large-sized phonetic decision tree is selected as an initial model set, and model complexity is computed by adding a penalty parameter which alters according to the amount of adaptation data. Largely attributed to the reasonable selection of initial models and the integration of stochastic and aptotic of MDL criterion, the proposed method gains high performance by combining with speaker adaptation.

  14. Dynamic analysis of fault rockburst based on gradient-dependent plasticity and energy criterion

    Institute of Scientific and Technical Information of China (English)

    Xuebin Wang; Xiaobin Yang; Zhihui Zhang; Yishan Pan

    2004-01-01

    Fault rockburst is treated as a strain localization problem under dynamic loading condition considering strain gradient and strain rate. As a kind of dynamic fracture phenomena, rockburst has characteristics of strain localization, which is considered as a one-dimensional shear problem subjected to normal compressive stress and tangential shear stress. The constitutive relation of rock material is bilinear (elastic and strain softening) and sensitive to shear strain rate. The solutions proposed based on gradientdependent plasticity show that intense plastic strain is concentrated in fault band and the thickness of the band depends on the characteristic length of rock material. The post-peak stiffness of the fault band was determined according to the constitutive parameters of rock material and shear strain rate. Fault band undergoing strain softening and elastic rock mass outside the band constitute a system and the instability criterion of the system was proposed based on energy theory. The criterion depends on the constitutive relation of rock material, the structural size and the strain rate. The static result regardless of the strain rate is the special case of the present analytical solution. High strain rate can lead to instability of the system.

  15. Generalized Griffith criterion for dynamic fracture and the stability of crack motion at high velocities

    Science.gov (United States)

    Adda-Bedia, M.; Arias, R.; Ben Amar, M.; Lund, F.

    1999-08-01

    We use Eshelby's energy momentum tensor of dynamic elasticity to compute the forces acting on a moving crack front in a three-dimensional elastic solid [Philos. Mag. 42, 1401 (1951)]. The crack front is allowed to be any curve in three dimensions, but its curvature is assumed small enough so that near the front the dynamics is locally governed by two-dimensional physics. In this case the component of the elastic force on the crack front that is tangent to the front vanishes. However, both the other components, parallel and perpendicular to the direction of motion, do not vanish. We propose that the dynamics of cracks that are allowed to deviate from straight line motion is governed by a vector equation that reflects a balance of elastic forces with dissipative forces at the crack tip, and a phenomenological model for those dissipative forces is advanced. Under certain assumptions for the parameters that characterize the model for the dissipative forces, we find a second order dynamic instability for the crack trajectory. This is signaled by the existence of a critical velocity Vc such that for velocities VVc it is governed by KII≠0. This result provides a qualitative explanation for some experimental results associated with dynamic fracture instabilities in thin brittle plates. When deviations from straight line motion are suppressed, the usual equation of straight line crack motion based on a Griffiths-like criterion is recovered.

  16. Failure criterion for graphene in biaxial loading—a molecular dynamics study

    Science.gov (United States)

    Yazdani, Hessam; Hatami, Kianoosh

    2015-09-01

    Molecular dynamics simulations are carried out in order to develop a failure criterion for infinite/bulk graphene in biaxial tension. Stresses along the principal edge configurations of graphene (i.e. armchair and zigzag directions) are normalized to the corresponding uniaxial ultimate strength values. The combinations of normalized stresses resulting in the failure of graphene are used to define failure envelopes (limiting stress ratio surfaces). Results indicate that a bilinear failure envelope can be used to represent the tensile strength of graphene in biaxial loading at different temperatures with reasonable accuracy. A circular failure envelope is also introduced for practical applications. Both failure envelopes define temperature-independent upper limits for the feasible combinations of normalized stresses for a graphene sheet in biaxial loading. Predicted failure modes of graphene under biaxial loading are also shown and discussed.

  17. Diagonal recurrent neural network based adaptive control of nonlinear dynamical systems using lyapunov stability criterion.

    Science.gov (United States)

    Kumar, Rajesh; Srivastava, Smriti; Gupta, J R P

    2017-03-01

    In this paper adaptive control of nonlinear dynamical systems using diagonal recurrent neural network (DRNN) is proposed. The structure of DRNN is a modification of fully connected recurrent neural network (FCRNN). Presence of self-recurrent neurons in the hidden layer of DRNN gives it an ability to capture the dynamic behaviour of the nonlinear plant under consideration (to be controlled). To ensure stability, update rules are developed using lyapunov stability criterion. These rules are then used for adjusting the various parameters of DRNN. The responses of plants obtained with DRNN are compared with those obtained when multi-layer feed forward neural network (MLFFNN) is used as a controller. Also, in example 4, FCRNN is also investigated and compared with DRNN and MLFFNN. Robustness of the proposed control scheme is also tested against parameter variations and disturbance signals. Four simulation examples including one-link robotic manipulator and inverted pendulum are considered on which the proposed controller is applied. The results so obtained show the superiority of DRNN over MLFFNN as a controller. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  18. Probability Criterion for a Dynamic Financial Model with Short-Selling Allowed

    Institute of Scientific and Technical Information of China (English)

    韩其恒; 唐万生; 李光泉

    2003-01-01

    Probability criterion has its practical significance, and its investment decision-making is determined by the expected discounted wealth. In a complete, standard financial market with short-selling allowed, this paper probes into the investment decision-making with probability criterion. The upper limit of criterion function is obtained. The corresponding discounted wealth process and hedging portfolio process are provided. Finally, an illustrative example of one-dimensional constant-coefficient financial market is given.

  19. Characterization of Multiaxial Stress-Strain Response of Tube Metal from Double-Sided Hydro-Bulging Test Based on Hosford's 1979 Yield Criterion

    Science.gov (United States)

    Cui, Xiao-Lei; Yang, Zhai-Ping; Wang, Xiao-Song

    2017-01-01

    To further explore the characterization of the multiaxial stress-strain responses of anisotropic tube metal from double-sided hydro-bulging tests, an analytical model for the equivalent stress and equivalent strain calculation was derived based on Hosford's 1979 yield criterion. Furthermore, thin-walled 5052-O aluminum alloy tubes were used to conduct the bulging experiment with an external pressure of 85 MPa. After the experimental data were substituted into the above analytical model, the Voce equation was used to fit the equivalent stress-strain relationship. It is concluded that the stress versus strain curves of the 5052-O tubes are strongly dependent on the loaded stress states, the adopted yield criteria, and the anisotropy coefficients. The external pressure of 85 MPa had little or no effect on the stress versus strain curves of the tubes, but the locations of the multiaxial stress versus strain curves were lower than that of the uniaxial stress versus strain curve. Moreover, the curve from Hosford's 1979 yield criterion not only had a higher saturation stress and material constant value than the curve from Mises and Hill's 1948 yield criteria but also had a dependence on the anisotropy coefficient.

  20. A universal criterion for plastic yielding of metallic glasses with a (T/Tg) 2/3 temperature dependence.

    Science.gov (United States)

    Johnson, W L; Samwer, K

    2005-11-04

    Room temperature (TR) elastic constants and compressive yield strengths of approximately 30 metallic glasses reveal an average shear limit gammaC=0.0267+/-0.0020, where tauY=gamma CG is the maximum resolved shear stress at yielding, and G the shear modulus. The gammaC values for individual glasses are correlated with t=TR/Tg , and gamma C for a single glass follows the same correlation (vs t=T/Tg). A cooperative shear model, inspired by Frenkel's analysis of the shear strength of solids, is proposed. Using a scaling analysis leads to a universal law tauCT/G=gammaC0-gammaC1(t)2/3 for the flow stress at finite T where gammaC0=(0.036+/-0.002) and gammaC1=(0.016+/-0.002).

  1. Yielding and post-yield behaviour of closed-cell cellular materials under multiaxial dynamic loading

    Science.gov (United States)

    Vesenjak, Matej; Ren, Zoran

    2016-05-01

    The paper focuses on characterisation of yielding and post-yield behaviour of metals with closed-cell cellular structure when subjected to multiaxial dynamic loading, considering the influence of the relative density, base material, strain rate and pore gas pressure. Research was conducted by extensive parametric fully-coupled computational simulations using the finite element code LS-DYNA. Results have shown that the macroscopic yield stress of cellular material rises with increase of the relative density, while its dependence on the hydrostatic stress decreases. The yield limit also rises with increase of the strain rate, while the hydrostatic stress influence remains more or less the same at different strain-rates. The macroscopic yield limit of the cellular material is also strongly influenced by the choice of base material since the base materials with higher yield limit contribute also to higher macroscopic yield limit of the cellular material. By increasing the pore gas filler pressure the dependence on hydrostatic stress increases while at the same time the yield surface shifts along the hydrostatic axis in the negative direction. This means that yielding at compression is delayed due to influence of the initial pore pressure and occurs at higher compressive loading, while the opposite is true for tensile loading.

  2. Mohr-Coulomb yield criterion in rock plastic mechanics%岩石塑性变形条件下的Mohr-Coulomb屈服准则

    Institute of Scientific and Technical Information of China (English)

    王红才; 赵卫华; 孙东生; 郭彬彬

    2012-01-01

    Conventional Mohr-Coulomb strength criterion only describing the relationship between normal stress and shear stress on the failure surface at the peak strength is used as a criterion to determine whether the rock has failed. This study expands the concept of the Mohr-Coulomb strength criterion by suggesting that the Mohr-Coulomb yield criterion can express the stress relationship of strain and stress of failure surface under various stress states after plastic deformation occurs. Based on the experimental study, an experiment approach which employs triaxial compression testing data to determine plastic parameters c and cp which vary with the internal variable k was established, and parameter expression used to assess the accuracy of isotropic modeling and some testing results were given. The Mohr-Coulomb yield criterion of isotropic hardening or softening, in which stress-strain curves of whole process is simplified into a four-line model using initial, peak and remnant parameters of rock, is more applicable than the trilinear model by Toshikazu. The result in this study provides theoretical and experimental basis for engineering and geological numerical simulation, thus being of instructive importance.%传统的Mohr-Coulomb强度准则仅描述了峰值强度状态下正应力和剪应力之间的关系,作为岩石破坏的判据.本文拓展概念,提出Mohr-Coulomb屈服准则表述岩石发生塑性变形后不同应力状态下屈服面的应力应变关系.在总结实验研究的基础上建立了使用三轴压缩试验数据确定塑性参数c和Φ随内变量κ变化的实验技术方法,给出了评价各向同性模型精度的参量表达以及某些测试结果.采用具有各向同性强(软)化规律的Mohr-Coulomb屈服准则,利用岩石的初始屈服、峰值屈服和残余屈服三组参数可以将全过程应力应变曲线简化表征为四直线模型,它比三线性模型有更广泛的适用性.本文的结果为工程地质数值模

  3. Constraining millennial scale dynamics of a Greenland tidewater glacier for the verification of a calving criterion based numerical model

    Science.gov (United States)

    Lea, J.; Mair, D.; Rea, B.; Nick, F.; Schofield, E.

    2012-04-01

    The ability to successfully model the behaviour of Greenland tidewater glaciers is pivotal to understanding the controls on their dynamics and potential impact on global sea level. However, to have confidence in the results of numerical models in this setting, the evidence required for robust verification must extend well beyond the existing instrumental record. Perhaps uniquely for a major Greenland outlet glacier, both the advance and retreat dynamics of Kangiata Nunata Sermia (KNS), Nuuk Fjord, SW Greenland over the last ~1000 years can be reasonably constrained through a combination of geomorphological, sedimentological and archaeological evidence. It is therefore an ideal location to test the ability of the latest generation of calving criterion based tidewater models to explain millennial scale dynamics. This poster presents geomorphological evidence recording the post-Little Ice Age maximum dynamics of KNS, derived from high-resolution satellite imagery. This includes evidence of annual retreat moraine complexes suggesting controlled rather than catastrophic retreat between pinning points, in addition to a series of ice dammed lake shorelines, allowing detailed interpretation of the dynamics of the glacier as it thinned and retreated. Pending ground truthing, this evidence will contribute towards the calibration of results obtained from a calving criterion numerical model (Nick et al, 2010), driven by an air temperature reconstruction for the KNS region determined from ice core data.

  4. Asymmetric correlation of sovereign bond yield dynamics in the Eurozone

    Directory of Open Access Journals (Sweden)

    Dajcman Silvo

    2013-01-01

    Full Text Available This paper examines the symmetry of correlation of sovereign bond yield dynamics between eight Eurozone countries (Austria, Belgium, France, Germany, Ireland, Italy, Portugal, and Spain in the period from January 3, 2000 to August 31, 2011. Asymmetry of correlation is investigated pair-wise by applying the test of Yongmiao Hong, Jun Tu, and Guofu Zhou (2007. Whereas the test of Hong, Tu, and Zhou (2007 is static, the present paper provides also a dynamic version of the test and identifies time periods when the correlation of Eurozone sovereign bond yield dynamics became asymmetric. We identified seven pairs of sovereign bond markets for which the null hypothesis of symmetry in correlation of sovereign bond yield dynamics can be rejected. Calculating rolling-window exceedance correlation, we found that the time-varying upper- (i.e. for positive yield changes and lower-tail correlations (i.e. for negative yield changes for pair-wise observed sovereign bond markets normally follow each other closely, yet during some time periods (for most pair-wise observed countries, these periods are around the September 11 attack on the New York City WTC and around the start of the Greek debt crisis the difference in correlation does increase. The results show that the upper- and lower-tail correlation was symmetric before the Eurozone debt crisis for most of the pair-wise observed sovereign bond markets but has become much less symmetric since then.

  5. Power-law decay exponents: A dynamical criterion for predicting thermalization

    Science.gov (United States)

    Távora, Marco; Torres-Herrera, E. J.; Santos, Lea F.

    2017-01-01

    From the analysis of the relaxation process of isolated lattice many-body quantum systems quenched far from equilibrium, we deduce a criterion for predicting when they are certain to thermalize. It is based on the algebraic behavior ∝t-γ of the survival probability at long times. We show that the value of the power-law exponent γ depends on the shape and filling of the weighted energy distribution of the initial state. Two scenarios are explored in detail: γ ≥2 and γ energy distribution of the initial state is ergodically filled and the eigenstates are uncorrelated, so thermalization is guaranteed to happen. In this case, the power-law behavior is caused by bounds in the energy spectrum. Decays with γ energy eigenstates are correlated and signal lack of ergodicity. They are typical of systems undergoing localization due to strong onsite disorder and are found also in clean integrable systems.

  6. Investigation of transient dynamics of capillary assisted particle assembly yield

    Science.gov (United States)

    Virganavičius, D.; Juodėnas, M.; Tamulevičius, T.; Schift, H.; Tamulevičius, S.

    2017-06-01

    In this paper, the transient behavior of the particle assembly yield dynamics when switching from low yield to high yield deposition at different velocity and thermal regimes is investigated. Capillary force assisted particle assembly (CAPA) using colloidal suspension of green fluorescent 270 nm diameter polystyrene beads was performed on patterned poly (dimethyl siloxane) substrates using a custom-built deposition setup. Two types of patterns with different trapping site densities were used to assess CAPA process dynamics and the influence of pattern density and geometry on the deposition yield transitions. Closely packed 300 nm diameter circular pits ordered in hexagonal arrangement with 300 nm pitch, and 2 × 2 mm2 square pits with 2 μm spacing were used. 2-D regular structures of the deposited particles were investigated by means of optical fluorescence and scanning electron microscopy. The fluorescence micrographs were analyzed using a custom algorithm enabling to identify particles and calculate efficiency of the deposition performed at different regimes. Relationship between the spatial distribution of particles in transition zone and ambient conditions was evaluated and quantified by approximation of the yield profile with a logistic function.

  7. Dynamic modelling of pectin extraction describing yield and functional characteristics

    DEFF Research Database (Denmark)

    Andersen, Nina Marianne; Cognet, T.; Santacoloma, P. A.

    2017-01-01

    A dynamic model of pectin extraction is proposed that describes pectin yield, degree of esterification and intrinsic viscosity. The dynamic model is one dimensional in the peel geometry and includes mass transport of pectin by diffusion and reaction kinetics of hydrolysis, degradation and de-esterification....... The model takes into account the effects of the process conditions such as temperature and acid concentration on extraction kinetics. It is shown that the model describes pectin bulk solution concentration, degree of esterification and intrinsic viscosity in pilot scale extractions from lime peel...

  8. Nutrient dynamics, primary production and fisheries yields of lagoons

    OpenAIRE

    Nixon, S W

    1982-01-01

    Differences appear to have a marked influence on the species composition of lagoon ecosystems around the world, but there are some remarkable similarities in nutrient dynamics, the standing crop of phytoplankton, annual primary production, and fisheries yields of many lagoons. For example, in many of the systems reviewed, the annual phosphate cycle was similar in timing and magnitude, primary production amounted to some 200-400 g C m super(-1) yr super(-1). There appears to be an empirical co...

  9. Bed Stability and Debris Flow Erosion: A Dynamic "Shields Criterion" Associated with Bed Structure

    Science.gov (United States)

    Longjas, A.; Hill, K. M.

    2015-12-01

    Debris flows are mass movements that play an important role in transporting sediment from steep uplands to rivers at lower slopes. As the debris flow moves downstream, it entrains materials such as loose boulders, gravel, sand and mud deposited locally by shorter flows such as slides and rockfalls. To capture the conditions under which debris flows entrain bed sediment, some models use something akin to the Shields' criterion and an excess shear stress of the flow. However, these models typically neglect granular-scale effects in the bed which can modify the conditions under which a debris flow is erosional or depositional. For example, it is well known that repeated shearing causes denser packing in loose dry soils, which undoubtedly changes their resistance to shear. Here, we present laboratory flume experiments showing that the conditions for entrainment by debris flows is significantly dependent on the aging of an erodible bed even for narrowly distributed spherical particles. We investigate this quantitatively using particle tracking measurements to quantify instantaneous erosion rates and the evolving bed structure or "fabric". With progressive experiments we find a signature that emerges in the bed fabric that is correlated with an increasing apparent "fragility" of the bed. Specifically, a system that is originally depositional may become erosional after repeated debris flow events, and an erodible bed becomes increasingly erodible with repeated flows. We hypothesize that related effects of bed aging at the field scale may be partly responsible for the increasing destructiveness of secondary flows of landslides and debris flows.

  10. Cause of Errors Associated with Application of Drucker-Prager Yield Criterion in MSC/NASTRAN Program%MSC/NASTRAN程序中Drucker-Prager屈服准则引起误差的原因探讨

    Institute of Scientific and Technical Information of China (English)

    王进军

    2000-01-01

    When the Drucker-Prager yield criterion is used, the MSC/NASTRAN program frequently predicts noticeable errors. The relevant part of NASTRAN Handbook was checked and some errors in the elasto-plastics theory used in NASTRAN were detected in this paper. The procurement to prove these errors was verified by numerical calculation.

  11. Functional dynamic factor models with application to yield curve forecasting

    KAUST Repository

    Hays, Spencer

    2012-09-01

    Accurate forecasting of zero coupon bond yields for a continuum of maturities is paramount to bond portfolio management and derivative security pricing. Yet a universal model for yield curve forecasting has been elusive, and prior attempts often resulted in a trade-off between goodness of fit and consistency with economic theory. To address this, herein we propose a novel formulation which connects the dynamic factor model (DFM) framework with concepts from functional data analysis: a DFM with functional factor loading curves. This results in a model capable of forecasting functional time series. Further, in the yield curve context we show that the model retains economic interpretation. Model estimation is achieved through an expectation- maximization algorithm, where the time series parameters and factor loading curves are simultaneously estimated in a single step. Efficient computing is implemented and a data-driven smoothing parameter is nicely incorporated. We show that our model performs very well on forecasting actual yield data compared with existing approaches, especially in regard to profit-based assessment for an innovative trading exercise. We further illustrate the viability of our model to applications outside of yield forecasting.

  12. ASYMPTOTIC REALIZATION OF THE CRITERION FOR QUANTUM INTEGRABILITY OF A BOSON SYSTEM WITH DYNAMIC SYMMETRY

    NARCIS (Netherlands)

    PAAR, [No Value; VORKAPIC, D; DIEPERINK, AEL

    1991-01-01

    We investigate the energy-level statistics in dependence on the boson number and the underlying classical motion for a system or collective states of zero angular momentum in gamma-soft nuclei described in the framework of the O(6) dynamical symmetry of the interacting boson model. This presents a r

  13. Analysis of faults stability with dynamic phenomena in the mine based on slide criterion and in-situ stress measurement

    Institute of Scientific and Technical Information of China (English)

    SONG Wei-hua; WANG Yu-feng; WANG Xin-hua

    2008-01-01

    For the study on the relationship between the dynamic phenomena in the mining such as mine earthquakes,outburst and faults slide,firstly,double shear friction experiments of sandstone were made,and its slide criterion was suggested considering the viewing of engineering.Secondly,in order to study the stability of underground rock and zone of tectonic stress field,based on the analysis on distribution characteristic of initial rock stress measurements,the geology structural model was built and tectonic stress field was made a back-analysis by applying finite element method.The calculating results fit with the analysis result of earthquakes mechanism and the distribution characteristic of the measurements.The high stress regional centers station locates discontinuous zone of I level faults and is corresponding to underground earthquakes scene.From then it is certain that tectonic stress is the major origin and necessary condition of mine earthquakes.The instability slide of the faults is the main manifest and the mining activity is the leading factor.Beipiao fault has a dominate effect on other sub faults and tectonic stress area and is dynamical fountain of dynamic phenomena in the Beipiao Mines.

  14. Analysis of faults stability with dynamic phenomena in the mine based on slide criterion and in-situ stress measurement

    Institute of Scientific and Technical Information of China (English)

    SONG Wei-hua; WANG Yu-feng; WANG Xin-hua

    2008-01-01

    For the study on the relationshfp between the dynamic phenomena in the min-ing such as mine earthquakes, outburst and faults slide, firstly, double shear friction ex-periments of sandstone were made, and its slide criterion was suggested considering the viewing of engineering. Secondly, in order to study the stability of underground rock and zone of tectonic stress field, based on the analysis on distribution characteristic of initial rock stress measurements, the geology structural model was built and tectonic stress field was made a back-analysis by applying finite element method. The calculating results fit with the analysis result of earthquakes mechanism and the distribution characteristic of the measurements. The high stress regional centers station locates discontinuous zone of I level faults and is corresponding to underground earthquakes scene. From then it is cer-tain that tectonic stress is the major origin and necessary condition of mine earthquakes. The instability slide of the faults is the main manifest and the mining activity is the leading factor. Beipiao fault has a dominate effect on other sub faults and tectonic stress area and is dynamical fountain of dynamic phenomena in the Beipiao Mines.

  15. Stability Criterion for Humanoid Running

    Institute of Scientific and Technical Information of China (English)

    LIZhao-Hui; HUANGQiang; LIKe-Jie

    2005-01-01

    A humanoid robot has high mobility but possibly risks of tipping over. Until now, one main topic on humanoid robots is to study the walking stability; the issue of the running stability has rarely been investigated. The running is different from the walking, and is more difficult to maintain its dynamic stability. The objective of this paper is to study the stability criterion for humanoid running based on the whole dynamics. First, the cycle and the dynamics of running are analyzed. Then, the stability criterion of humanoid running is presented. Finally, the effectiveness of the proposed stability criterion is illustrated by a dynamic simulation example using a dynamic analysis and design system (DADS).

  16. 基于综合结构势概念的结构性原状黄土屈服准则%Yield criterion of intact structural loess based on integrated structural potential concept

    Institute of Scientific and Technical Information of China (English)

    钟祖良; 王睢; 刘新荣

    2015-01-01

    To investigate the destruction characteristics of intact structural loess under loading conditions, triaxial shear tests are conducted on Q2 intact loess. Based on the experimental results, a structural variable parameter m of soil is defined, which can consider the spherical stress, deviatoric stress, matric suction and other factors. By means of method for calculating the structural parameter m based on the experiment, the relationships among shear strength parameters c, j and structural parameter m are found out, the curve equations of m with c, j are deduced, respectively. By introducing the curve equations into Drucker-Prager (D-P) criterion, a modified yield criterion applicable to Q2 intact loess is established. The modified yield criterion can consider the structural effect of intact Q2 loess and describe the structural characteristics of loess very well. Besides, the yield surface reflecting the impact of structural parameters is drawn. The rationality of the modified yield criterion is verified by comparing the results of the modified yield criterion with those obtained from the triaxial tests.%为了研究结构性原状黄土在加载条件下的破坏特性,采用试验的方法对 Q2原状黄土进行了非饱和土三轴剪切试验研究。基于试验成果,定义了可以考虑球应力、偏应力和基质吸力等因素的土的结构性变量参数m。利用通过试验提出的m的计算方法,找出抗剪强度参数 c、j值与 m 之间的关系,推导出 m 与 c、j值的曲线方程,分别将曲线方程代入到Drucker-Prager(D-P)准则方程中对其进行修正,建立了结构性Q2原状黄土的修正屈服准则,该准则可以考虑Q2原状黄土的结构性影响,符合黄土的结构性特性,绘制出可反应结构性参数影响的屈服面,并验证了其合理性。

  17. Applicability Analysis of Yield Criterion for Advanced High Strength Steels DP590 under Warm-forming Condition%高强钢板DP590温热环境下屈服准则适用性分析

    Institute of Scientific and Technical Information of China (English)

    程诚; 刁可山; 吴向东; 王文平; 万敏; 蔡正阳

    2016-01-01

    板料成形过程中温度的变化会影响其塑性流动行为。以先进高强钢板 DP590为研究对象,通过不同温度下单拉试验和不同温度不同加载比例双拉试验得到其在温热环境下的试验屈服轨迹,结果显示温度不仅会影响 DP590钢板屈服轨迹的大小,而且影响屈服轨迹的形状。将试验屈服轨迹和几种理论屈服轨迹进行对比分析,表明Yld2000-2D屈服准则与试验结果吻合较好,同时等效应力应变点分析也显示出Yld2000-2D屈服准则满足塑性力学的单一曲线假设规律。针对Yld2000-2D屈服准则,采用不同温度下的试验数据计算出不同温度下的各向异性参数,通过拟合获得各向异性参数与温度的四次多项式函数关系,建立温度相关Yld2000-2D屈服准则,并与常规Yld2000-2D屈服准则对比分析,结果显示温度相关Yld2000-2D屈服准则更加适合描述DP590钢板温热环境下的屈服行为。%In order to investigate the temperature effect on the yield behavior of the DP590 under warm forming condition, the yield loci are obtained by conducting biaxial and uniaxial tensile tests under different directions. The comparison of homogenized stresses of different tensile directions shows DP590 sheet obeys isotropic hardening law approximately and the shape and size of the yield loci are influenced by the temperature evidently. The yield criterion of Yld2000-2D proves to be a better choice for the accurate description of yield behavior under the warm-forming condition by comparing between the experimental and theoretical yield loci. Based on the equivalent stress and strain associated with the given yield criteria under different proportional loading paths, the applicability of Yld2000-2D yield criterion is verified. Furthermore, four polynomial function of temperature are used to fit the variation trend of the anisotropic parameters in Yld2000-2d yield function under different temperatures. The

  18. Study on Splitting Failure Criterion of Surrounding Rock under Point Yield%裂纹尖端屈服条件下的围岩劈裂破坏判据研究

    Institute of Scientific and Technical Information of China (English)

    刘宁; 张春生

    2011-01-01

    The new fracture criterion is set up because the elastic fracture mechanics is not applicable for the plastic zone. Considering the interaction among cracks, the sliding multi-cracks model is adopted to simulate the splitting failure of rock in axial pressure. The plastic radius is calculated by Mises yield criterion and the dissipation energy for plastic deformation in total volume is also computed. The splitting failure criterion is established with principle of energy balance. The criterion is applied to the excavation of Langyashan pumped storage power station. The distribution charts of splitting failure zone are obtained, which coincides with results obtained by Lajtai empirical formula. It shows that the method is effective and feasible, which provides prediction criterion for splitting failure of underground engineering excavation in high geostress.%针对裂纹尖端附近出现塑性区时线弹性断裂力学理论不适用的问题,采用滑移裂纹组模型模拟岩石在轴向压力下的劈裂破坏,根据Mises屈服准则求出塑性区半径和整个体积中塑性变形引起的耗散能,基于能量平衡原理得到小范围屈服条件下的劈裂判据,将该判据应用于琅琊山抽水蓄能水电站机组的开挖分析中,计算获得了劈裂破坏区范围分布图,并与Lajtai经验公式进行比较,结果较为一致,表明该方法可行、有效,为地下工程开挖引起的劈裂破坏提供了预测判据.

  19. Photosynthetic Quantum Yield Dynamics: From Photosystems to Leaves

    NARCIS (Netherlands)

    Hogewoning, S.W.; Wientjes, E.; Douwstra, P.; Trouwborst, G.; Ieperen, van W.; Croce, R.; Harbinson, J.

    2012-01-01

    The mechanisms underlying the wavelength dependence of the quantum yield for CO2 fixation (a) and its acclimation to the growth-light spectrum are quantitatively addressed, combining in vivo physiological and in vitro molecular methods. Cucumber (Cucumis sativus) was grown under an artificial

  20. Photosynthetic Quantum Yield Dynamics : From Photosystems to Leaves

    NARCIS (Netherlands)

    Hogewoning, Sander W.; Wientjes, Emilie; Douwstra, Peter; Trouwborst, Govert; van Ieperen, Wim; Croce, Roberta; Harbinson, Jeremy

    The mechanisms underlying the wavelength dependence of the quantum yield for CO2 fixation (alpha) and its acclimation to the growth-light spectrum are quantitatively addressed, combining in vivo physiological and in vitro molecular methods. Cucumber (Cucumis sativus) was grown under an artificial

  1. A dynamic tomato growth and yield model (TOMGRO).

    NARCIS (Netherlands)

    Jones, J.W.; Dayan, E.; Allen, L.H.; Keulen, van H.; Challa, H.

    1991-01-01

    Models of the greenhouse environment and of crops are needed to determine optimal strategies for environment control in regions where new greenhouse industries are developing. In this research, a physiological model of tomato crop development and yield was developed. A series of differential

  2. Soil phosphorus dynamics and availability and irrigated coffee yield

    Directory of Open Access Journals (Sweden)

    Thiago Henrique Pereira Reis

    2011-04-01

    Full Text Available Research data have demonstrated that the P demand of coffee (Coffea arabica L. is similar to that of short-cycle crops. In this context, the objective of this study was to evaluate the influence of annual P fertilization on the soil P status by the quantification of labile, moderately labile, low-labile, and total P fractions, associating them to coffee yield. The experiment was installed in a typical dystrophic Red Latosol (Oxisol cultivated with irrigated coffee annually fertilized with triple superphosphate at rates of 0, 50, 100, 200, and 400 kg ha-1 P2O5. Phosphorus fractions were determined in two soil layers: 0-10 and 10-20 cm. The P leaf contents and coffee yield in 2008 were also evaluated. The irrigated coffee responded to phosphate fertilization in the production phase with gains of up to 138 % in coffee yield by the application of 400 kg ha-1 P2O5. Coffee leaf P contents increased with P applications and stabilized around 1.98 g kg-1, at rates of 270 kg ha-1 P2O5 and higher. Soil P application caused, in general, an increase in bioavailable P fractions, which constitute the main soil P reservoir.

  3. The Prospects for High-Yield ICF with a Z-Pinch Driven Dynamic Hohlraum

    Energy Technology Data Exchange (ETDEWEB)

    CHANDLER, GORDON A.; CHRIEN, R.; COOPER, GARY WAYNE; DERZON, MARK S.; DOUGLAS, MELISSA R.; HEBRON, DAVID E.; LASH, JOEL S.; LEEPER, RAMON J.; MATZEN, M. KEITH; MEHLHORN, THOMAS A.; NASH, THOMAS J.; OLSON, RICHARD E.; PETERSON, D.L.; RUIZ, CARLOS L.; SANFORD, THOMAS W. L.; SLUTZ, STEPHEN A.

    1999-09-07

    Recent success with the Sandia Z machine has renewed interest in utilizing fast z-pinenes for ICF. One promising concept places the ICF capsule internal to the imploding z-pinch. At machine parameters relevant to achieving high yield, the imploding z-pinch mass has sufficient opacity to trap radiation giving rise to a dynamic hohlraum. The concept utilizes a 12 MJ, 54 MA z-pinch driver producing a capsule drive temperature exceeding 300 eV to realize a 550 MJ thermonuclear yield. They present the current high-yield design and its development that supports high-yield ICF with a z-pinch driven dynamic hohlraum.

  4. Carotenoid incorporation into microsomes: yields, stability and membrane dynamics

    Science.gov (United States)

    Socaciu, Carmen; Jessel, Robert; Diehl, Horst A.

    2000-12-01

    The carotenoids β-carotene (BC), lycopene (LYC), lutein (LUT), zeaxanthin (ZEA), canthaxanthin (CTX) and astaxanthin (ASTA) have been incorporated into pig liver microsomes. Effective incorporation concentrations in the range of about 1-6 nmol/mg microsomal protein were obtained. A stability test at room temperature revealed that after 3 h BC and LYC had decayed totally whereas, gradually, CTX (46%), LUT (21%), ASTA (17%) and ZEA (5%) decayed. Biophysical parameters of the microsomal membrane were changed hardly by the incorporation of carotenoids. A small rigidification may occur. Membrane anisotropy seems to offer only a small tolerance for incorporation of carotenoids and seems to limit the achievable incorporation concentrations of the carotenoids into microsomes. Microsomes instead of liposomes should be preferred as a membrane model to study mutual effects of carotenoids and membrane dynamics.

  5. Dynamic yield and tensile strengths of spark plasma sintered alumina

    Science.gov (United States)

    Girlitsky, I.; Zaretsky, E.; Kalabukhov, S.; Dariel, M.; Frage, N.

    2014-05-01

    Fully dense alumina samples with 0.6 μm grain size were produced from alumina powder using Spark Plasma Sintering and tested in two types of VISAR-instrumented planar impact tests. In the tests of the first type the samples of 0.28 to 6-mm thickness were loaded by 1-mm tungsten impactors accelerated up to a velocity of about 1 km/s. These tests were aimed to study the Hugoniot elastic limit (HEL) of the SPS-processed alumina and the decay of the elastic precursor wave with propagation distance. In the second type of test the samples of ~3-mm thickness were loaded by 1-mm copper impactors accelerated up to velocities 100-1000 m/s. These tests were aimed to study the dynamic tensile (spall) strength of the alumina. The data on tensile fracture of the alumina demonstrate a monotonic decline of the spall strength with the amplitude of the loading stress pulse. The data on the decay of the elastic precursor wave allows for determining the rates of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of shock-induced inelastic deformation and, thus, to derive some conclusions concerning the mechanisms responsible of the deformation.

  6. Extended use of ISO 15739 incremental signal-to-noise ratio as reliability criterion for multiple-slope wide dynamic range image capture

    Science.gov (United States)

    Hertel, Dirk

    2009-01-01

    In the emerging field of automotive vision, video capture is the critical front-end of driver assistance and active safety systems. Previous photospace measurements have shown that light levels in natural traffic scenes may contain an extremely wide intra-scene intensity range. This requires the camera to have a wide dynamic range (WDR) for it to adapt quickly to changing lighting conditions and to reliably capture all scene detail. Multiple-slope CMOS technology offers a cost-effective way of adaptively extending dynamic range by partially resetting (recharging) the CMOS pixel once or more often within each frame time. This avoids saturation and leads to a response curve with piecewise linear slopes of progressively increasing compression. It was observed that the image quality from multiple-slope image capture is strongly dependent on the control (height and time) of each reset barrier. As compression and thus dynamic range increase there is a trade-off against contrast and detail loss. Incremental signal-to-noise ratio (iSNR) is proposed in ISO 15739 for determining dynamic range. Measurements and computer simulations revealed that the observed trade-off between WDR extension and the loss of local detail could be explained by a drop in iSNR at each reset point. If a reset barrier is not optimally placed then iSNR may drop below the detection limit so that an 'iSNR hole' appears in the dynamic range. Thus ISO 15739 iSNR has gained extended utility: it not only measures the dynamic range limits but also defines dynamic range as the intensity range where detail detection is reliable. It has become a critical criterion when designing adaptive barrier control algorithms that maximize dynamic range while maintaining the minimum necessary level of detection reliability.

  7. [Effects of nitrogen fertilization on population dynamics and yield of high-yielding wheat and on alteration of soil nitrogen].

    Science.gov (United States)

    Ye, You-Liang; Wang, Gui-Liang; Zhu, Yun-Ji; Li, Huan-Huan; Huang, Yu-Fang

    2010-02-01

    Taking wheat varieties Yumai 49-198 (multi-spike phenotype) and Lankao Aizao 8 (large-spike phenotype) as test materials, field experiments were conducted at Wenxian and Lankao sites of Henan Province to study the effects of nitrogen fertilization on their population dynamics and yield and on the alteration of soil nitrogen. Five nitrogen application rates, i. e., 0, 90, 180, 270, and 360 N kg x hm(-2) were installed. The population amount of the two test varieties were all increased after emergence, reached the highest at jointing stage, and decreased afterwards. As for Yumai 49-198, its population amount had no significant differences at wintering and turning-green stages among the five nitrogen application rates and two experimental sites, but differed significantly after jointing stage with the nitrogen application rates. For Lankao Aizao 8, its population amount had no significant differences among the nitrogen application rates during whole growth period. The grain yield of the two varieties increased with the increase of nitrogen fertilization rate, but excessive nitrogen fertilization decreased the grain yield. Yumai 49-198 had the highest yield at 270 N kg x hm(-2), being 9523 and 9867 kg x hm(-2) at Wenxian and Lanako sites, respectively, while Lankao Aizao 8 had the highest yield at 180 N kg x hm(-2), being 9258 and 9832 kg x hm(-2) at Wenxian and Lanako sites, respectively. With the increase of nitrogen fertilization rate, soil nitrate N concentration and apparent nitrogen loss increased. At Wenxian and Lankao sites, the apparent soil nitrogen loss for Yumai 49-198 was 32.56% - 51.84% and - 16.7% - 42.6% of fertilized nitrogen, and that for Lankao Aizao 8 was 18.58% - 52.94% and - 11.5% - 45.8% of fertilized nitrogen, respectively. Considering the yield and environmental effect comprehensively, the nitrate N concentration in 0-90 cm soil layer in our case should not be exceeded 120 - 140 kg x hm(-2), and the maximal nitrogen application rate should not

  8. Yield and Failure Behavior Investigated for Cross-Linked Phenolic Resins Using Molecular Dynamics

    Science.gov (United States)

    Monk, Joshua D.; Lawson, John W.

    2016-01-01

    Molecular dynamics simulations were conducted to fundamentally evaluate the yield and failure behavior of cross-linked phenolic resins at temperatures below the glass transition. Yield stress was investigated at various temperatures, strain rates, and degrees of cross-linking. The onset of non-linear behavior in the cross-linked phenolic structures was caused by localized irreversible molecular rearrangements through the rotation of methylene linkers followed by the formation or annihilation of neighboring hydrogen bonds. The yield stress results, with respect to temperature and strain rate, could be fit by existing models used to describe yield behavior of amorphous glasses. The degree of cross-linking only indirectly influences the maximum yield stress through its influence on glass transition temperature (Tg), however there is a strong relationship between the degree of cross-linking and the failure mechanism. Low cross-linked samples were able to separate through void formation, whereas the highly cross-linked structures exhibited bond scission.

  9. Dynamic yield and tensile strength of aluminum single crystals at temperatures up to the melting point

    Energy Technology Data Exchange (ETDEWEB)

    Kanel, G. I.; Razorenov, S. V.; Baumung, K.; Singer, J.

    2001-07-01

    This article presents experimental results of the dynamic yield strength and dynamic tensile strength ({open_quotes}spall strength{close_quotes}) of aluminum single crystals at shock-wave loading as a function of temperature. The load duration was {similar_to}40 and {similar_to}200 ns. The temperature varied from 20 to 650{degree}C which is only by 10{degree}C below the melting temperature. A linear growth of the dynamic yield strength by more than a factor of 4 was observed within this temperature range. This is attributed to the phonon drag effect on the dislocation motion. High dynamic tensile strength was maintained over the whole temperature range, including the conditions at which melting should start in a material under tension. This could be an indication of the existence of superheated states in solid crystals. {copyright} 2001 American Institute of Physics.

  10. A spectral-spatial-dynamic hierarchical Bayesian (SSD-HB) model for estimating soybean yield

    Science.gov (United States)

    Kazama, Yoriko; Kujirai, Toshihiro

    2014-10-01

    A method called a "spectral-spatial-dynamic hierarchical-Bayesian (SSD-HB) model," which can deal with many parameters (such as spectral and weather information all together) by reducing the occurrence of multicollinearity, is proposed. Experiments conducted on soybean yields in Brazil fields with a RapidEye satellite image indicate that the proposed SSD-HB model can predict soybean yield with a higher degree of accuracy than other estimation methods commonly used in remote-sensing applications. In the case of the SSD-HB model, the mean absolute error between estimated yield of the target area and actual yield is 0.28 t/ha, compared to 0.34 t/ha when conventional PLS regression was applied, showing the potential effectiveness of the proposed model.

  11. On the Role of Diffusion Behaviors in Stability Criterion for p-Laplace Dynamical Equations with Infinite Delay and Partial Fuzzy Parameters under Dirichlet Boundary Value

    Directory of Open Access Journals (Sweden)

    Ruofeng Rao

    2013-01-01

    Full Text Available By the way of Lyapunov-Krasovskii functional approach and some variational methods in the Sobolev space W01,p(Ω, a global asymptotical stability criterion for p-Laplace partial differential equations with partial fuzzy parameters is derived under Dirichlet boundary condition, which gives a positive answer to an open problem proposed in some related literatures. Different from many previous related literatures, the nonlinear p-Laplace diffusion item plays its role in the new criterion though the nonlinear p-Laplace presents great difficulties. Moreover, numerical examples illustrate that our new stability criterion can judge what the previous criteria cannot do.

  12. Dynamic Relationship between Bonds Yields of Malaysia, Singapore, Thailand, India and Japan

    Directory of Open Access Journals (Sweden)

    Cheng Fan Fah

    2012-01-01

    Full Text Available In this paper, we study the dynamic relationship of bond yields of Malaysia, Singapore, Thailand, India, and Japan by using 43 observations for the period of 2007 to July 2010. This study analyzes the government bond returns and the yields curve for the five countries with different term to maturity of 5 years and 15 years. The results indicate that the yields on government bond for the five countries are all consistent with the term structure of interest rate theory where the yields to maturity increase as the term to maturity increase during the period of 2007 to 2010. There is also evidence supporting the yields to maturity for all five countries are significantly stationary at order one or I(1. Moreover, the findings also show that there are a few groups of countries were found co-integration with one vector. In long run, the results find that between the group of countries, Malaysia and India, Singapore and Thailand, and Singapore and India, the bond returns for the 5 and15 years term to maturity are co-integrated with at least one co-integrating vectors.

  13. An Empirical Kaiser Criterion.

    Science.gov (United States)

    Braeken, Johan; van Assen, Marcel A L M

    2016-03-31

    In exploratory factor analysis (EFA), most popular methods for dimensionality assessment such as the screeplot, the Kaiser criterion, or-the current gold standard-parallel analysis, are based on eigenvalues of the correlation matrix. To further understanding and development of factor retention methods, results on population and sample eigenvalue distributions are introduced based on random matrix theory and Monte Carlo simulations. These results are used to develop a new factor retention method, the Empirical Kaiser Criterion. The performance of the Empirical Kaiser Criterion and parallel analysis is examined in typical research settings, with multiple scales that are desired to be relatively short, but still reliable. Theoretical and simulation results illustrate that the new Empirical Kaiser Criterion performs as well as parallel analysis in typical research settings with uncorrelated scales, but much better when scales are both correlated and short. We conclude that the Empirical Kaiser Criterion is a powerful and promising factor retention method, because it is based on distribution theory of eigenvalues, shows good performance, is easily visualized and computed, and is useful for power analysis and sample size planning for EFA. (PsycINFO Database Record

  14. Spatio-temporal dynamics of maize yield water constraints under climate change in Spain.

    Science.gov (United States)

    Ferrero, Rosana; Lima, Mauricio; Gonzalez-Andujar, Jose Luis

    2014-01-01

    Many studies have analyzed the impact of climate change on crop productivity, but comparing the performance of water management systems has rarely been explored. Because water supply and crop demand in agro-systems may be affected by global climate change in shaping the spatial patterns of agricultural production, we should evaluate how and where irrigation practices are effective in mitigating climate change effects. Here we have constructed simple, general models, based on biological mechanisms and a theoretical framework, which could be useful in explaining and predicting crop productivity dynamics. We have studied maize in irrigated and rain-fed systems at a provincial scale, from 1996 to 2009 in Spain, one of the most prominent "hot-spots" in future climate change projections. Our new approach allowed us to: (1) evaluate new structural properties such as the stability of crop yield dynamics, (2) detect nonlinear responses to climate change (thresholds and discontinuities), challenging the usual linear way of thinking, and (3) examine spatial patterns of yield losses due to water constraints and identify clusters of provinces that have been negatively affected by warming. We have reduced the uncertainty associated with climate change impacts on maize productivity by improving the understanding of the relative contributions of individual factors and providing a better spatial comprehension of the key processes. We have identified water stress and water management systems as being key causes of the yield gap, and detected vulnerable regions where efforts in research and policy should be prioritized in order to increase maize productivity.

  15. Sediment yield in human-induced degraded catchments of the Northern Ethiopian Highlands: magnitude and dynamics

    Science.gov (United States)

    Vanmaercke, M.; Zenebe, A.; Poesen, J.; Nyssen, J.; Verstraeten, G.; Deckers, J.; Govers, G.

    2009-04-01

    The Northern Ethiopian Highlands are a fragile environment, characterised by steep slopes, intense rainfall and a sparse vegetation cover. The extreme poverty, stagnating technology and high population and livestock densities induce serious soil erosion problems. This not only leads to lower crop yields but also reduces the life expectancy of many dams and reservoirs (used for power generation or water supply in the dry season) as a result of massive sedimentation. Although these problems demand for a thorough solution, little is known about the magnitude and dynamics of sediment transport in the Northern Ethiopian Highlands. Therefore an intensive measuring campaign was conducted during the rainy season of 2006 in 10 subcatchments of the Geba (drainage area: 5180 km2), a tributary of the Tekeze (Atbara) river. These subcatchments range in size from 120 km2 to 4330 km2 and represent contrasting environments typical for the Northern Ethiopian Highlands. In this paper, the results of this measuring campaign are discussed. The sediment yield for the 10 subcatchments range between 400 and 2500 t km-2 a-1, with an average value of 1400 t km-2 a-1. The uncertainties on these sediment yields were assessed by Monte Carlo simulations. Important spatial and temporal variations in suspended sediment export were noted. A few flash floods were recorded in detail for which clear positive hysteresis effects in sediment concentration were found. The environmental factors, causing the large differences in sediment yield between the studied catchments were assessed by means of a semi-quantitative model.

  16. Dynamic visco-plastic memorial nested yield surface model of soil

    Institute of Scientific and Technical Information of China (English)

    Haiyang ZHUANG; Guoxing CHEN; Dinghua ZHU

    2008-01-01

    Under cyclic loadings, the plastic strain of soft soil will take place under very small shear strain. So the viscoplastic model is appropriate to be used to model the dynamic characteristics of soft soil. Based on the principles of geotechnical plastic mechanics, the incremental visco-plastic memorial nested yield surface model is developed by using the field theory of nonlinear isotropic materials and the theory of kinematical hardening modulus. At the end of anyone time increment, the inverted loading surface, the damaged surface and the initial loading surface which is tangent with the inside of inverted loading surface are memorized respectively. The kinematical behavior of yield surface is defined by using these three surfaces. The developed model in this paper is successfully implemented in ABAQUS using FORTRAN subroutine. The predicted stress-strain relationships of soft soil are compared with the test results given by dynamic triaxial tests. It is proved that the cyclic undrained stress-strain relation of soils can be fairly simulated by the model. At last, the nonlinear earthquake response of a representative soft site in Nanjing city is calculated with the dynamic behavior of soils modeled by the new developed model. The results are accordant to the earthquake response of soft site given by other scholars.

  17. A nonlinear dynamical system approach for the yielding behaviour of a viscoplastic material.

    Science.gov (United States)

    Burghelea, Teodor; Moyers-Gonzalez, Miguel; Sainudiin, Raazesh

    2017-02-15

    A nonlinear dynamical system model that approximates a microscopic Gibbs field model for the yielding of a viscoplastic material subjected to varying external stresses recently reported in R. Sainudiin, M. Moyers-Gonzalez and T. Burghelea, Soft Matter, 2015, 11(27), 5531-5545 is presented. The predictions of the model are in fair agreement with microscopic simulations and are in very good agreement with the micro-structural semi-empirical model reported in A. M. V. Putz and T. I. Burghelea, Rheol. Acta, 2009, 48, 673-689. With only two internal parameters, the nonlinear dynamical system model captures several key features of the solid-fluid transition observed in experiments: the effect of the interactions between microscopic constituents on the yield point, the abruptness of solid-fluid transition and the emergence of a hysteresis of the micro-structural states upon increasing/decreasing external forces. The scaling behaviour of the magnitude of the hysteresis with the degree of the steadiness of the flow is consistent with previous experimental observations. Finally, the practical usefulness of the approach is demonstrated by fitting a rheological data set measured with an elasto-viscoplastic material.

  18. Spatio-temporal dynamics of maize yield water constraints under climate change in Spain.

    Directory of Open Access Journals (Sweden)

    Rosana Ferrero

    Full Text Available Many studies have analyzed the impact of climate change on crop productivity, but comparing the performance of water management systems has rarely been explored. Because water supply and crop demand in agro-systems may be affected by global climate change in shaping the spatial patterns of agricultural production, we should evaluate how and where irrigation practices are effective in mitigating climate change effects. Here we have constructed simple, general models, based on biological mechanisms and a theoretical framework, which could be useful in explaining and predicting crop productivity dynamics. We have studied maize in irrigated and rain-fed systems at a provincial scale, from 1996 to 2009 in Spain, one of the most prominent "hot-spots" in future climate change projections. Our new approach allowed us to: (1 evaluate new structural properties such as the stability of crop yield dynamics, (2 detect nonlinear responses to climate change (thresholds and discontinuities, challenging the usual linear way of thinking, and (3 examine spatial patterns of yield losses due to water constraints and identify clusters of provinces that have been negatively affected by warming. We have reduced the uncertainty associated with climate change impacts on maize productivity by improving the understanding of the relative contributions of individual factors and providing a better spatial comprehension of the key processes. We have identified water stress and water management systems as being key causes of the yield gap, and detected vulnerable regions where efforts in research and policy should be prioritized in order to increase maize productivity.

  19. On the Role of Diffusion Behaviors in Stability Criterion for p-Laplace Dynamical Equations with Infinite Delay and Partial Fuzzy Parameters under Dirichlet Boundary Value

    OpenAIRE

    Ruofeng Rao; Zhilin Pu; Shouming Zhong; Jialin Huang

    2013-01-01

    By the way of Lyapunov-Krasovskii functional approach and some variational methods in the Sobolev space ${W}_{0}^{1,p}\\left(Ω\\right)$ , a global asymptotical stability criterion for p-Laplace partial differential equations with partial fuzzy parameters is derived under Dirichlet boundary condition, which gives a positive answer to an open problem proposed in some related literatures. Different from many previous related literatures, the nonlinear p-Laplace diffusion item plays its role in the...

  20. Quantifying the effect of heat stress on daily milk yield and monitoring dynamic changes using an adaptive dynamic model.

    Science.gov (United States)

    André, G; Engel, B; Berentsen, P B M; Vellinga, Th V; Lansink, A G J M Oude

    2011-09-01

    Automation and use of robots are increasingly being used within dairy farming and result in large amounts of real time data. This information provides a base for the new management concept of precision livestock farming. From 2003 to 2006, time series of herd mean daily milk yield were collected on 6 experimental research farms in the Netherlands. These time series were analyzed with an adaptive dynamic model following a Bayesian method to quantify the effect of heat stress. The effect of heat stress was quantified in terms of critical temperature above which heat stress occurred, duration of heat stress periods, and resulting loss in milk yield. In addition, dynamic changes in level and trend were monitored, including the estimation of a weekly pattern. Monitoring comprised detection of potential outliers and other deteriorations. The adaptive dynamic model fitted the data well; the root mean squared error of the forecasts ranged from 0.55 to 0.99 kg of milk/d. The percentages of potential outliers and signals for deteriorations ranged from 5.5 to 9.7%. The Bayesian procedure for time series analysis and monitoring provided a useful tool for process control. Online estimates (based on past and present only) and retrospective estimates (determined afterward from all data) of level and trend in daily milk yield showed an almost yearly cycle that was in agreement with the calving pattern: most cows calved in winter and early spring versus summer and autumn. Estimated weekly patterns in terms of weekday effects could be related to specific management actions, such as change of pasture during grazing. For the effect of heat stress, the mean estimated critical temperature above which heat stress was expected was 17.8±0.56°C. The estimated duration of the heat stress periods was 5.5±1.03 d, and the estimated loss was 31.4±12.2 kg of milk/cow per year. Farm-specific estimates are helpful to identify management factors like grazing, housing and feeding, that affect the

  1. Nanostructured surfaces yield earlier: Molecular dynamics study of nanoindentation into adatom islands

    Science.gov (United States)

    Ziegenhain, Gerolf; Urbassek, Herbert M.

    2010-04-01

    Using molecular-dynamics simulation we investigate nanoindentation into an fcc metal surface covered by an adatom island. Small islands are pushed into the solid and transported away by prismatic dislocation loops, and no defects remain under the indenter; thereafter indentation proceeds as for a flat surface. For large islands, the island boundaries do not influence indentation. Most interesting is the intermediate case, where the island size is comparable to the contact radius of the indenter at the onset of plasticity. Here plasticity starts immediately at the surface under the weakest step edges bounding the island. The dislocations are pinned to the step edges and dislocation activity remains localized under the island. For this intermediate case, the surface is weakest and yields earliest.

  2. Influence of microbially enriched vermicompost on yield, microbial dynamics and soil nutrients

    Directory of Open Access Journals (Sweden)

    Neeldurai Tensingh Baliah

    2016-12-01

    Full Text Available The present study has been conducted to explore the microbial enrichment of vermicompost with microbial inoculants such as Azospirillum brasilense, Bacillus megaterium and Pseudomonas fluorescens. The enrichment had a positive effect on the crop response, soil biological activity and soil nutrient status. The results indicated that the enriched vermicompost significantly increased crop response of Okra with reference to yield attributes. Further, the microbial enriched vermicompost significantly improved the soil microbial dynamics such as bacteria and fungi and nutrient status such as total N and available P in the amended soil. The enrichment with agronomically important microbes such as nitrogen fixer, phosphate solubilizer and plant growth promoting rhizobacteria had positive response but the response varied among the beneficial microorganisms.

  3. Photoisomerization dynamics of a rhodopsin-based molecule (potential molecular switch) with high quantum yields

    Science.gov (United States)

    Allen, Roland; Jiang, Chen-Wei; Zhang, Xiu-Xing; Fang, Ai-Ping; Li, Hong-Rong; Xie, Rui-Hua; Li, Fu-Li

    2015-03-01

    It is worthwhile to explore the detailed reaction dynamics of various candidates for molecular switches, in order to understand, e.g., the differences in quantum yields and switching times. Here we report density-functional-based simulations for the rhodopsin-based molecule 4-[4-Methylbenzylidene]-5-p-tolyl-3,4-dihydro-2H-pyrrole (MDP), synthesized by Sampedro et al. We find that the photoisomerization quantum yields are remarkably high: 82% for cis-to-trans, and 68% for trans-to-cis. The lifetimes of the S1 excited state in cis-MDP in our calculations are in the range of 900-1800 fs, with a mean value of 1270 fs, while the range of times required for full cis-to-trans isomerization are 1100-2000 fs, with a mean value of 1530 fs. In trans-MDP, the calculated S1 excited state lifetimes are 860-2140 fs, with a mean value of 1330 fs, and with the full trans-to-cis isomerization completed about 200 fs later. In both cases, the dominant reaction mechanism is rotation around the central C =C bond (connected to the pyrroline ring), and de-excitation occurs at an avoided crossing between the ground state and the lowest singlet state, near the midpoint of the rotational pathway. Research Fund for the Doctoral Program of Higher Education of China; Fundamental Research Funds for the Central Universities; Robert A. Welch Foundation; National Natural Science Foundation of China.

  4. Extended Jury criterion

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper,algebraic criteria are established to determine whether or not a real coefficient polynomial has one or two pairs of conjugate complex roots whose moduli are equal to 1 and the other roots have moduli less than 1 directly from its coefficients.The form and the function of the criteria are similar to those of the Jury criterion which can be used to determine whether or not all the moduli of the roots of a real coefficient polynomial are less than 1.

  5. A scale invariance criterion for LES parametrizations

    Directory of Open Access Journals (Sweden)

    Urs Schaefer-Rolffs

    2015-01-01

    Full Text Available Turbulent kinetic energy cascades in fluid dynamical systems are usually characterized by scale invariance. However, representations of subgrid scales in large eddy simulations do not necessarily fulfill this constraint. So far, scale invariance has been considered in the context of isotropic, incompressible, and three-dimensional turbulence. In the present paper, the theory is extended to compressible flows that obey the hydrostatic approximation, as well as to corresponding subgrid-scale parametrizations. A criterion is presented to check if the symmetries of the governing equations are correctly translated into the equations used in numerical models. By applying scaling transformations to the model equations, relations between the scaling factors are obtained by demanding that the mathematical structure of the equations does not change.The criterion is validated by recovering the breakdown of scale invariance in the classical Smagorinsky model and confirming scale invariance for the Dynamic Smagorinsky Model. The criterion also shows that the compressible continuity equation is intrinsically scale-invariant. The criterion also proves that a scale-invariant turbulent kinetic energy equation or a scale-invariant equation of motion for a passive tracer is obtained only with a dynamic mixing length. For large-scale atmospheric flows governed by the hydrostatic balance the energy cascade is due to horizontal advection and the vertical length scale exhibits a scaling behaviour that is different from that derived for horizontal length scales.

  6. Responses of Greenhouse Tomato and Pepper Yields and Nitrogen Dynamics to Applied Compound Fertilizers

    Institute of Scientific and Technical Information of China (English)

    ZHU Jian-Hua; LI Xiao-Lin; ZHANG Fu-Suo; LI Jun-Liang; P.CHRISTIE

    2004-01-01

    Yield and N uptake of tomato (Lycopersicum esculentum Mill.) and pepper (Capsicum annuum L.) crops in five successive rotations receiving two compound fertilizers (12-12-17 and 21-8-11 N-P2O5-K2O) were studied to determine 1)crop responses,2) dynamics of NO3-N and NH4-N in different soil layers,3) N balance and 4) system-level N efficiencies.Five treatments (2 fertilizers,2 fertilizer rates and a control),each with three replicates,were arranged in the study.The higher N fertilizer rate,300 kg N ha-1 (versus 150 kg N ha-i),returned higher vegetable fruit yields and total aboveground N uptake with the largest crop responses occurring for the low-N fertilizer (12-12-17) applied at 300 kg N ha-1 rather than with the high-N fertilizer (21-8-11). Ammonium-N in the top 90 cm of the soil profile declined during the experiment,while nitrate-N remained at a similar level throughout the experiment with the lower rate of fertilizer N.At the higher rate of N fertilizer there was a continuous NO3-N accumulation of over 800 kg N ha-1. About 200 kg N ha-1 was applied with irrigation to each crop using NO3-contaminated groundwater. In general,about 50% of the total N input was recovered from all treatments. Pepper,relative to tomato,used N more efficiently with smaller N losses,but the crops utilized less than 29% of the fertilizer N over the two and a half-year period. Local agricultural practices maintained high residual soil nutrient status. Thus,optimization of irrigation is required to minimize nitrate leaching and maximize crop N recovery.

  7. Vegetation dynamics using AVHRR/NDVI: Regional climate, carbon dioxide fertilization and crop yield relations

    Science.gov (United States)

    Lim, Chai Kyung

    Vegetation development is closely related to climate factors, and, therefore, it is important to understand how it responds to global climate changes. For the last two decades it has been possible to monitor vegetation development at continental or global scales utilizing remote sensing Normalized Difference Vegetation Index (NDVI) data. We have developed a frequency analysis method to investigate land's vegetation greenness change and its response to the El Nino Southern Oscillation (ENSO). We found an ENSO influence on a tropical forest, southern semi-deciduous forest and a northeastern mixed forest. Our analysis shows the annual trends in vegetation greenness respond more sensitively than averaging methods. Atmospheric CO2 increase is another concern for climate change, for which fertilization effect on land vegetation has been suggested. Atmospheric CO2 and NDVI have a seasonal pattern of negative correlation, which makes it difficult to discern any positive influence of CO2 on vegetation. We adopted the concept of the rate of change in atmospheric CO2 concentration and NDVI to overcome this set pattern, and to reveal undergoing fluctuations. We found evidence that suggests a CO2 fertilization effect in some arctic and sub arctic regions and northern and inland parts of the eastern humid temperate zones in North America. Although NDVI reveals the vegetation greenness only at a fixed time and location, we have transformed NDVI effectively to describe the vegetation growth dynamics in the form of a new index, Normalized Growth Index (NGI). Utilizing NGI, we found the vegetation growth during the growing season is highly negatively correlated with the initial minimum vegetation greenness. One needs to be careful when comparing Net Primary Production (NPP) using NDVI between different types of vegetation, because the same NDVI value can imply the existence of different biomass due to different Leaf Area Index (LAI). To overcome this difficulty we have developed

  8. The effect of Guinier-Preston zones on the dynamic yield stress of alloys under the shock-wave load

    Science.gov (United States)

    Malashenko, V. V.

    2017-05-01

    The movement of an ensemble of edge dislocations under shock-wave action on an alloy that contains the Guinier-Preston zones has been theoretically studied. The analytical expression for the contribution of the Guinier-Preston zones into the dynamic yield stress has been obtained and it has been shown that this contribution is affected by the density of mobile dislocations. The numerical estimates have shown that the formation of these zones lead to a substantial increase in the dynamic yield stress of alloys.

  9. Nitrogen uptake dynamics, yield and quality as influenced by nitrogen fertilization in Piel de sapo melon

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos, M. T.; Cabello, M. J.; Cartagena, M. C.; Tarquis, A. M.; Arce, A.; Ribas, F.

    2012-11-01

    The need to reduce nitrogen (N) fertilizer pollution strengthens the importance of improving the utilization efficiency of applied N to crops. This requires knowledge of crop N uptake characteristics and how fertilization management affects it. A three-year field experiment was conducted from May to September in central Spain to investigate the influence of different N rates, which ranged from 11 to 393 kg ha{sup -}1, applied through drip irrigation, on the dynamics of N uptake, nitrogen use efficiency (NUE), fruit yield and quality of a Piel de sapo melon crop (Cucumis melo L. cv. Sancho). Both N concentration and N content increased in different plant parts with the N rate. Leaves had the highest N concentration, which declined by 40-50% from 34-41 days after transplanting (DAT), while the highest N uptake rate was observed from 30-35 to 70-80 DAT, coinciding with fruit development. In each year, NUE declined with increasing N rate. With N fertilizer applications close to the optimum N rate of 90-100 kg ha -1, the fruits removed approximately 60 kg N ha -1, and the amount of N in the crop residue was about 80 kg N ha -1; this serves to replenish the organic nutrient pool in the soil and may be used by subsequent crops following mineralization. (Author) 36 refs.

  10. Theory of nonlinear elasticity, stress-induced relaxation, and dynamic yielding in dense fluids of hard nonspherical colloids.

    Science.gov (United States)

    Zhang, Rui; Schweizer, Kenneth S

    2012-04-21

    We generalize the microscopic naïve mode coupling and nonlinear Langevin equation theories of the coupled translation-rotation dynamics of dense suspensions of uniaxial colloids to treat the effect of applied stress on shear elasticity, cooperative cage escape, structural relaxation, and dynamic and static yielding. The key concept is a stress-dependent dynamic free energy surface that quantifies the center-of-mass force and torque on a moving colloid. The consequences of variable particle aspect ratio and volume fraction, and the role of plastic versus double glasses, are established in the context of dense, glass-forming suspensions of hard-core dicolloids. For low aspect ratios, the theory provides a microscopic basis for the recently observed phenomenon of double yielding as a consequence of stress-driven sequential unlocking of caging constraints via reduction of the distinct entropic barriers associated with the rotational and translational degrees of freedom. The existence, and breadth in volume fraction, of the double yielding phenomena is predicted to generally depend on both the degree of particle anisotropy and experimental probing frequency, and as a consequence typically occurs only over a window of (high) volume fractions where there is strong decoupling of rotational and translational activated relaxation. At high enough concentrations, a return to single yielding is predicted. For large aspect ratio dicolloids, rotation and translation are always strongly coupled in the activated barrier hopping event, and hence for all stresses only a single yielding process is predicted.

  11. A Less Conservative Circle Criterion

    OpenAIRE

    2008-01-01

    A weak form of the Circle Criterion for Lur'e systems is stated. The result allows prove global boundedness of all system solutions. Moreover such a result can be employed to enlarge the set of nonlinearities for which the standard Circle Criterion can guarantee absolute stability.

  12. Fly ash application in nutrient poor agriculture soils: impact on methanotrophs population dynamics and paddy yields.

    Science.gov (United States)

    Singh, Jay Shankar; Pandey, Vimal Chandra

    2013-03-01

    There are reports that the application of fly ash, compost and press mud or a combination thereof, improves plant growth, soil microbial communities etc. Also, fly ash in combination with farmyard manure or other organic amendments improves soil physico-chemical characteristics, rice yield and microbial processes in paddy fields. However, the knowledge about the impact of fly ash inputs alone or in combination with other organic amendments on soil methanotrophs number in paddy soils is almost lacking. We hypothesized that fly ash application at lower doses in paddy agriculture soil could be a potential amendment to elevate the paddy yields and methanotrophs number. Here we demonstrate the impact of fly ash and press mud inputs on number of methanotrophs, antioxidants, antioxidative enzymatic activities and paddy yields at agriculture farm. The impact of amendments was significant for methanotrophs number, heavy metal concentration, antioxidant contents, antioxidant enzymatic activities and paddy yields. A negative correlation was existed between higher doses of fly ash-treatments and methanotrophs number (R(2)=0.833). The content of antioxidants and enzymatic activities in leaves of higher doses fly ash-treated rice plants increased in response to stresses due to heavy metal toxicity, which was negatively correlated with rice grain yield (R(2)=0.944) and paddy straw yield (R(2)=0.934). A positive correlation was noted between heavy metals concentrations and different antioxidant and enzymatic activities across different fly ash treated plots.The data of this study indicate that heavy metal toxicity of fly ash may cause oxidative stress in the paddy crop and the antioxidants and related enzymes could play a defensive role against phytotoxic damages. We concluded that fly ash at lower doses with press mud seems to offer the potential amendments to improving soil methanotrophs population and paddy crop yields for the nutrient poor agriculture soils.

  13. Entropic criterion for model selection

    Science.gov (United States)

    Tseng, Chih-Yuan

    2006-10-01

    Model or variable selection is usually achieved through ranking models according to the increasing order of preference. One of methods is applying Kullback-Leibler distance or relative entropy as a selection criterion. Yet that will raise two questions, why use this criterion and are there any other criteria. Besides, conventional approaches require a reference prior, which is usually difficult to get. Following the logic of inductive inference proposed by Caticha [Relative entropy and inductive inference, in: G. Erickson, Y. Zhai (Eds.), Bayesian Inference and Maximum Entropy Methods in Science and Engineering, AIP Conference Proceedings, vol. 707, 2004 (available from arXiv.org/abs/physics/0311093)], we show relative entropy to be a unique criterion, which requires no prior information and can be applied to different fields. We examine this criterion by considering a physical problem, simple fluids, and results are promising.

  14. ADATOM, VACANCY AND SPUTTERING YIELDS OF ENERGETIC Pt ATOMS IMPACTING ON Pt(100) BY MOLECULAR DYNAMICS SIMULATION

    Institute of Scientific and Technical Information of China (English)

    YE ZI-YAN; ZHANG QING-YU

    2001-01-01

    We have studied the influence of incident atoms with low energy on the Pt(100) surface by molecular dynamics simulation. The interaction potential obtained by the embedded atom method (EAM) was used in the simulation. The incident energy changes from 0.leV to 200eV, and the target temperature ranges from 100 to 500 K. The target scales are 6×6×4 and 8×8×4 fcc cells for lower and higher incident energies, respectively. The adatom, sputtering, vacancy and backscattering yields are calculated. It was found that there is a sputtering threshold for the incident energy. When the incident energy is higher than the sputtering threshold, the sputtering yield increases with the increase of incident energy, and the sputtering shows a symmetrical pattern. We found that the adatom and vacancy yields increase as the incident energy increases. The vacancy yields are much higher than those obtained by Monte Carlo simulation. The dependence of the adatom and sputtering yields on the incident energy and the relative atomistic mechanisms are discussed.

  15. Enrichment desired quality chitosan fraction and advance yield by sequential static and static-dynamic supercritical CO2.

    Science.gov (United States)

    Hsieh, Yi-Yin; Chin, Hui Yen; Tsai, Min-Lang

    2015-11-20

    This study aimed to establish the sequential static and static-dynamic supercritical carbon dioxide (SDCO2) fractionation conditions to obtain a higher yield and desired chitosan with lower polydispersity index (PDI) and higher degree of deacetylation (DD). The yield increased with increasing DD of used chitosan and amount of cosolvent. The yield of acetic acid cosolvent was higher than those of malic and citric acid cosolvents. SDCO2, compared to static supercritical carbon dioxide, has higher yield. The yield of extracted chitosan was 5.82-14.70% by SDCO2/acetic acid, which increases with increasing pressure. The DD of fractionated chitosan increased from 66.1% to 70.81-85.33%, while the PDI decreased from 3.97 to 1.69-3.16. The molecular weight changed from 622kDa to 412-649kDa, which increased as density of supercritical carbon dioxide increases. Hence, higher DD and lower PDI extracted chitosan can be obtained through controlling the temperature and pressure of SDCO2.

  16. Size-Dependent Biexciton Quantum Yields and Carrier Dynamics of Quasi-Two-Dimensional Core/Shell Nanoplatelets.

    Science.gov (United States)

    Ma, Xuedan; Diroll, Benjamin T; Cho, Wooje; Fedin, Igor; Schaller, Richard D; Talapin, Dmitri V; Gray, Stephen K; Wiederrecht, Gary P; Gosztola, David J

    2017-09-05

    Quasi-two-dimensional nanoplatelets (NPLs) possess fundamentally different excitonic properties from zero-dimensional quantum dots. We study lateral size-dependent photon emission statistics and carrier dynamics of individual NPLs using second-order photon correlation (g((2))(τ)) spectroscopy and photoluminescence (PL) intensity-dependent lifetime analysis. Room-temperature radiative lifetimes of NPLs can be derived from maximum PL intensity periods in PL time traces. It first decreases with NPL lateral size and then stays constant, deviating from the electric dipole approximation. Analysis of the PL time traces further reveals that the single exciton quantum yield in NPLs decreases with NPL lateral size and increases with protecting shell thickness, indicating the importance of surface passivation on NPL emission quality. Second-order photon correlation (g((2))(τ)) studies of single NPLs show that the biexciton quantum yield is strongly dependent on the lateral size and single exciton quantum yield of the NPLs. In large NPLs with unity single exciton quantum yield, the corresponding biexciton quantum yield can reach unity. These findings reveal that by careful growth control and core-shell material engineering, NPLs can be of great potential for light amplification and integrated quantum photonic applications.

  17. The Bohm criterion and sheath formation

    Energy Technology Data Exchange (ETDEWEB)

    Riemann, K.U. (Bochum Univ. (Germany). Inst. fuer Theoretische Physik 1)

    1990-11-01

    In the limit of a small Debye length ({lambda}{sub D}{yields}0) the analysis of the plasma boundary layer leads to a two scale problem of a collision free sheath and of a quasineutral presheath. Bohm's criterion expresses a necessary condition for the formation of a stationary sheath in front of a negative absorbing wall. The basic features of the plasma-sheath transition and their relation to the Bohm criterion are discussed and illustrated from a simple cold-ion fluid model. A rigorous kinetic analysis of the vicinity of the sheath edge allows to generalize Bohm's criterion acounting not only for arbitrary ion- and electron distributions, but also for general boundary conditions at the wall. It is shown that the generalized sheath condition is (apart from special exceptions) fulfilled marginally and related to a sheath edge field singularity. Due to this singularity a smooth matching of the presheath and sheath solutions requires an additional transition layer. Previous investigations concerning special problems of the plasma-sheath transition are reviewed in the light of the general relations. (orig.).

  18. Quantifying the effect of heat stress on daily milk yield and monitoring dynamic changes using an adaptive dynamic model

    NARCIS (Netherlands)

    Andre, G.; Engel, B.; Berentsen, P.B.M.; Vellinga, T.V.; Oude Lansink, A.G.J.M.

    2011-01-01

    Automation and use of robots are increasingly being used within dairy farming and result in large amounts of real time data. This information provides a base for the new management concept of precision livestock farming. From 2003 to 2006, time series of herd mean daily milk yield were collected on

  19. 基于最小一乘准则的中国粮食产量与影响因素的相关性分析%Relative analysis of China’s grain yield and influence factors based on criterion of least absolute deviation

    Institute of Scientific and Technical Information of China (English)

    顾乐民

    2013-01-01

    , of which the consumption of chemical fertilizer is still playing a positive roll up to now, while the total agricultural machinery power is dynamically in a saturated state. Theoretically it should have a “negative”effect now, but in reality it does not. The total sown area was the most influencing“positive”factor. The national grain yield may still grow further without increasing the total sown area, but increasing the sown area can rapidly boost the China’s nation grain yield. The total area affected by natural disaster imposed “negative” effect on the growth;However, the trend of its influence is increasing in terms of absolute values, but is decreasing in terms of relative values. By the huge impact and lagged effects of the rapid growing of the total employed population of primary industry in China during 1983-1993 period, the reduction of the total employed population of primary industry to grain growth constituted “negative” impact. With the modernization of agriculture and urbanization development, this “negative” impact continued to reduce. These conclusions give the specific quantitative values. The paper predictes that the grain yield for year 2012 is 5.9133 10× t, the later result indicates the absolute error is 8 1.78 10× t, and the relative error is 0.3%. For year 2013, the prediction is 6 6.1148 10× t. In the last the paper gives 8 some discussion about the LAD method, the exponential production functions and so on, and is concluded that the exponential production function under the meaning of LAD criterion to describe the relationships between China's grain yield and the main effect factors, has a certain accuracy and guiding sense.

  20. On the hodological criterion for homology.

    Science.gov (United States)

    Faunes, Macarena; Francisco Botelho, João; Ahumada Galleguillos, Patricio; Mpodozis, Jorge

    2015-01-01

    Owen's pre-evolutionary definition of a homolog as "the same organ in different animals under every variety of form and function" and its redefinition after Darwin as "the same trait in different lineages due to common ancestry" entail the same heuristic problem: how to establish "sameness."Although different criteria for homology often conflict, there is currently a generalized acceptance of gene expression as the best criterion. This gene-centered view of homology results from a reductionist and preformationist concept of living beings. Here, we adopt an alternative organismic-epigenetic viewpoint, and conceive living beings as systems whose identity is given by the dynamic interactions between their components at their multiple levels of composition. We posit that there cannot be an absolute homology criterion, and instead, homology should be inferred from comparisons at the levels and developmental stages where the delimitation of the compared trait lies. In this line, we argue that neural connectivity, i.e., the hodological criterion, should prevail in the determination of homologies between brain supra-cellular structures, such as the vertebrate pallium.

  1. On the hodological criterion for homology

    Directory of Open Access Journals (Sweden)

    Macarena eFaunes

    2015-06-01

    Full Text Available Owen’s pre-evolutionary definition of a homologue as the same organ in different animals under every variety of form and function and its redefinition after Darwin as the same trait in different lineages due to common ancestry entail the same heuristic problem: how to establish sameness. Although different criteria for homology often conflict, there is currently a generalized acceptance of gene expression as the best criterion. This gene-centered view of homology results from a reductionist and preformationist concept of living beings. Here, we adopt an alternative organismic-epigenetic viewpoint, and conceive living beings as systems whose identity is given by the dynamic interactions between their components at their multiple levels of composition. We posit that there cannot be an absolute homology criterion, and instead, homology should be inferred from comparisons at the levels and developmental stages where the delimitation of the compared trait lies. In this line, we argue that neural connectivity, i.e., the hodological criterion, should prevail in the determination of homologies between brain supra-cellular structures, such as the vertebrate pallium.

  2. On the hodological criterion for homology

    Science.gov (United States)

    Faunes, Macarena; Francisco Botelho, João; Ahumada Galleguillos, Patricio; Mpodozis, Jorge

    2015-01-01

    Owen's pre-evolutionary definition of a homolog as “the same organ in different animals under every variety of form and function” and its redefinition after Darwin as “the same trait in different lineages due to common ancestry” entail the same heuristic problem: how to establish “sameness.”Although different criteria for homology often conflict, there is currently a generalized acceptance of gene expression as the best criterion. This gene-centered view of homology results from a reductionist and preformationist concept of living beings. Here, we adopt an alternative organismic-epigenetic viewpoint, and conceive living beings as systems whose identity is given by the dynamic interactions between their components at their multiple levels of composition. We posit that there cannot be an absolute homology criterion, and instead, homology should be inferred from comparisons at the levels and developmental stages where the delimitation of the compared trait lies. In this line, we argue that neural connectivity, i.e., the hodological criterion, should prevail in the determination of homologies between brain supra-cellular structures, such as the vertebrate pallium. PMID:26157357

  3. DRUCKER-PRAGER YIELD CRITERIA IN VISCOELASTIC-PLASTIC CONSTITUTIVE MODEL FOR THE STUDY OF SEA ICE DYNAMICS

    Institute of Scientific and Technical Information of China (English)

    WANG Gang; JI Shun-ying; LV He-xiang; YUE Qian-jin

    2006-01-01

    Based on the characteristics of sea ice drifting and ridging at meso-small scale, the Drucker-Prager (D-P) yield criteria was introduced into the Viscoelastic-Plastic (VEP) constitutive model for the study of sea ice dynamics. In this model, the Kelvin-Vogit viscoelastic model was adopted in the elastic stage, and the associated normal flow rule was used in the plastic stage. Using the VEP model, the sea ice ridging process was simulated in an idealized rectangular basin, and the simulation results show that the simulated ice ridge thickness is consistent with the analytical solution. Moreover, the VEP model with the D-P yield criteria was also applied for the sea ice simulation of Bohai Sea, and the ice thickness, concentration, velocity, and ice stress were obtained in 48 h. The simulated thickness distributions agree well with the satellite images. The singular problem in the Mohr-Coulomb (M-C) yield criteria was overcome by the D-P yield criteria, and the computational efficiency was also improved. In the numerical simulations described above, the smoothed particle hydrodynamics was applied.

  4. A Planarity Criterion for Graphs

    CERN Document Server

    Dosen, Kosta

    2012-01-01

    It is proven that a connected graph is planar if and only if all its cocycles with at least four edges are "grounded" in the graph. The notion of grounding of this planarity criterion, which is purely combinatorial, stems from the intuitive idea that with planarity there should be a linear ordering of the edges of a cocycle such that in the two subgraphs remaining after the removal of these edges there can be no crossing of disjoint paths that join the vertices of these edges. The proof given in the paper of the right-to-left direction of the equivalence is based on Kuratowski's Theorem for planarity involving $K_{3,3}$ and $K_5$, but the criterion itself does not mention $K_{3,3}$ and $K_5$. Some other variants of the criterion are also shown necessary and sufficient for planarity.

  5. Inferring earthquake statistics from soft-glass dynamics below yield stress

    Science.gov (United States)

    Kumar, Pinaki; Toschi, Federico; Benzi, Roberto; Trampert, Jeannot

    2016-11-01

    The current practice to generate synthetic earthquake catalogs employs purely statistical models, mechanical methods based on ad-hoc constitutive friction laws or a combination of the above. We adopt a new numerical approach based on the multi-component Lattice Boltzmann method to simulate yield stress materials. Below yield stress, under shear forcing, we find that the highly intermittent in time, irreversible T1 topological changes in the soft-glass (termed plastic events) bear a statistical resemblance to seismic events, radiating elastic perturbations through the system. Statistical analysis reveals scaling laws for magnitude similar to the Gutenberg-Richter law for quakes, a recurrence time scale with similar slope, a well-defined clustering of events into causal-aftershock sequences and Poisson events leading to the Omori law. Additionally space intermittency reveals a complex multi-fractal structure, like real quakes, and a characterization of the stick-slip behavior in terms of avalanche size and time distribution agrees with the de-pinning transition. The model system once properly tuned using real earthquake data, may help highlighting the origin of scaling in phenomenological seismic power laws. This research was partly funded by the Shell-NWO/FOM programme "Computational sciences for energy research" under Project Number 14CSER022.

  6. A Failure Criterion for Concrete

    DEFF Research Database (Denmark)

    Ottosen, N. S.

    1977-01-01

    A four-parameter failure criterion containing all the three stress invariants explicitly is proposed for short-time loading of concrete. It corresponds to a smooth convex failure surface with curved meridians, which open in the negative direction of the hydrostatic axis, and the trace in the devi......A four-parameter failure criterion containing all the three stress invariants explicitly is proposed for short-time loading of concrete. It corresponds to a smooth convex failure surface with curved meridians, which open in the negative direction of the hydrostatic axis, and the trace...

  7. A Failure Criterion for Concrete

    DEFF Research Database (Denmark)

    Ottosen, N. S.

    1977-01-01

    A four-parameter failure criterion containing all the three stress invariants explicitly is proposed for short-time loading of concrete. It corresponds to a smooth convex failure surface with curved meridians, which open in the negative direction of the hydrostatic axis, and the trace in the devi......A four-parameter failure criterion containing all the three stress invariants explicitly is proposed for short-time loading of concrete. It corresponds to a smooth convex failure surface with curved meridians, which open in the negative direction of the hydrostatic axis, and the trace...

  8. Quantum molecular dynamics approach to estimate spallation yield from + 208Pb reaction at 800 MeV

    Indian Academy of Sciences (India)

    P K Sarkar; Maitreyee Nandy

    2003-10-01

    The spallation yield of neutrons and other mass fragments produced in 800 MeV proton induced reaction on 208Pb have been calculated in the framework of quantum molecular dynamics (QMD) model. The energy spectra and angular distribution have been calculated. Also, multiplicity distributions of the emitted neutrons and kinetic energy carried away by them have been estimated and compared with the available experimental data. The agreement is satisfactory. A major contribution to the neutron emission comes from statistical decay of the fragments. For mass and charge distributions of spallation productsthe QMD process gives rise to target-like and projectile-like fragments only.

  9. Criterion Reading Instructional Project (CRIP).

    Science.gov (United States)

    Linden Board of Education, NJ.

    This booklet describes the Linden Title I Program between the years 1971-1974, with a focus on the Criterion Reading Instructional Project (CRIP). The program (in Linden, New Jersey) evolved from a supplemental reading and mathematics program to a structured developmental program of language arts designed to meet the needs of primary grade…

  10. Angular criterion for distinguishing between Fraunhofer and Fresnel diffraction

    CERN Document Server

    Medina, F F; García-Sucerquia, J; Matteucci, G

    2003-01-01

    The distinction between Fresnel and Fraunhofer diffraction is a crucial condition for the accurate analysis of diffracting structures. In this paper we propose a criterion based on the angle subtended by the first zero of the diffraction pattern from the center of the diffracting aperture. The determination of the zero of the diffraction pattern is the crucial point for assuring the precision of the criterion. It mainly depends on the dynamical range of the detector. Therefore, the applicability of adequate thresholds for different detector types is discussed. The criterion is also generalized by expressing it in terms of the number of Fresnel zones delimited by the aperture. Simulations are reported for illustrating the feasibility of the criterion.

  11. Dynamic and rate-dependent yielding behavior of Co0.9Ni0.1 microcluster based magnetorheological fluids

    Science.gov (United States)

    Arief, Injamamul; Mukhopadhyay, P. K.

    2016-01-01

    In this paper we performed steady shear and oscillatory magnetorheological (MR) studies in magnetic fluids containing CoNi sub-micron sized clusters of 450 nm in diameter. Such Co-rich nanoclusters were synthesized by conventional homogeneous nucleation without any external surfactant or reducing agent in liquid polyol at elevated temperature. The x-ray diffraction, energy dispersive x-ray analysis, scanning and transmission electron microscopy studies were done for analyzing the sample composition and morphology. Two variants of fluid samples were prepared by dispersing 15 vol% and 20 vol% of CoNi powders in castor oil. Room temperature steady magnetoshear studies indicate viscoplastic behavior with stronger dependence of static yield stress on magnetization than a dipolar coupling that was operational in the dynamic yield stress. Magnetosweep measurements at constant shear rate showed interesting viscous relaxation at high magnetic fields. We also explored dynamical elastic behavior through oscillatory magnetorheological studies under both strain sweep and frequency sweep modes, and showed glass transition like phenomenon occurring in them above critical shear amplitudes.

  12. Marker selection by Akaike information criterion and Bayesian information criterion.

    Science.gov (United States)

    Li, W; Nyholt, D R

    2001-01-01

    We carried out a discriminant analysis with identity by descent (IBD) at each marker as inputs, and the sib pair type (affected-affected versus affected-unaffected) as the output. Using simple logistic regression for this discriminant analysis, we illustrate the importance of comparing models with different number of parameters. Such model comparisons are best carried out using either the Akaike information criterion (AIC) or the Bayesian information criterion (BIC). When AIC (or BIC) stepwise variable selection was applied to the German Asthma data set, a group of markers were selected which provide the best fit to the data (assuming an additive effect). Interestingly, these 25-26 markers were not identical to those with the highest (in magnitude) single-locus lod scores.

  13. 基于水沙动力过程的泥石流阻塞大河模式及判据研究%Criterion and patterns of debris flow blocking big river based on water and sediment dynamic processes

    Institute of Scientific and Technical Information of China (English)

    刘翠容; 姚令侃; 陈春光; 杜翠

    2012-01-01

      According to the characters of the submerged disk and the density current,the runout equations of the debris flow in the water is obtained, and the equation of the head-water level is given by the broad-crested weir theory. Based on the dynamic equation of the debris flow at different slopes,water and sediment dynamic processes, and the interaction between barriers dam of debris flow and main river were considered,and a model of the runout distance of debris flow in big river was established. In view of the phenomenon that the material erosion is very serious when debris flowing into big river,the erosion coeffi⁃cient is obtaineding using the test dates of flume experiment. Based on the total amount equation of debris flow was blocking given by Bifan ZHOU, a modal of the total amount of the big river blocked by debris flow was considered in hight of the erosion coefficient. The criterion of debris flow blocking big river was presented in terms of dynamic process and total amount of debris flow.%  根据潜坝壅堵模式的特点,基于异重流理论,给出了泥石流龙头在清水中的运动方程,并提出了有坎宽顶模型的潜坝壅堵上游水位计算式。基于水沙动力过程,以泥石流在坡度变化沟道内的运动方程为基础,考虑堰塞坝和主河水流的相互作用,给出了泥石流在主河中运移距离的计算公式;鉴于泥石流堵塞大河过程中物质流失严重的现象,根据水槽实验数据确定了流失系数;以周必凡提出的泥石流堵断主河总量的计算公式为基础,提出了按流失系数加以修正的泥石流阻塞大河物质总量条件。从而建立了基于动力学方程、物质总量的泥石流阻塞大河综合判据。

  14. 仿人机器人跑步稳定性准则%Stability Criterion for Humanoid Running

    Institute of Scientific and Technical Information of China (English)

    李朝晖; 黄强; 李科杰

    2005-01-01

    A humanoid robot has high mobility but possibly risks of tipping over. Until now, one main topic on humanoid robots is to study the walking stability; the issue of the running stability has rarely been investigated. The running is different from the walking, and is more difficult to maintain its dynamic stability. The objective of this paper is to study the stability criterion for humanoid running based on the whole dynamics. First, the cycle and the dynamics of running are analyzed. Then, the stability criterion of humanoid running is presented. Finally, the effectiveness of the proposed stability criterion is illustrated by a dynamic simulation example using a dynamic analysis and design system (DADS).

  15. A Focused Bayesian Information Criterion

    Directory of Open Access Journals (Sweden)

    Georges Nguefack-Tsague

    2014-01-01

    Full Text Available Myriads of model selection criteria (Bayesian and frequentist have been proposed in the literature aiming at selecting a single model regardless of its intended use. An honorable exception in the frequentist perspective is the “focused information criterion” (FIC aiming at selecting a model based on the parameter of interest (focus. This paper takes the same view in the Bayesian context; that is, a model may be good for one estimand but bad for another. The proposed method exploits the Bayesian model averaging (BMA machinery to obtain a new criterion, the focused Bayesian model averaging (FoBMA, for which the best model is the one whose estimate is closest to the BMA estimate. In particular, for two models, this criterion reduces to the classical Bayesian model selection scheme of choosing the model with the highest posterior probability. The new method is applied in linear regression, logistic regression, and survival analysis. This criterion is specially important in epidemiological studies in which the objective is often to determine a risk factor (focus for a disease, adjusting for potential confounding factors.

  16. Paleomagnetism as a structural polarity criterion: application to Tunisian diapirs

    Science.gov (United States)

    Henry, Bernard; Rouvier, Henri; Le Goff, Maxime; Smati, Amor; Hatira, Nouri; Laatar, Essaied; Mansouri, Abdelbaki; Perthuisot, Vincent

    2000-03-01

    In the Upper Aptian-Albian units, close to Triassic displaced bodies of northwestern Tunisia, the primary magnetization acquired during the Cretaceous period of normal magnetic polarity yields an unquestionable structural polarity criterion. The use of this criterion confirms the diapiric origin of these Triassic bodies and aids understanding of the evolution of the diapirs. It also appears to be a useful tool for the analysis of the geometry of overturning. An Eocene halokinesis on the platform south of the Tunisian Channel is also indicated by analysis of magnetic overprint in the Jebel Slata.

  17. Molecular dynamics simulations and docking enable to explore the biophysical factors controlling the yields of engineered nanobodies

    Science.gov (United States)

    Soler, Miguel A.; de Marco, Ario; Fortuna, Sara

    2016-01-01

    Nanobodies (VHHs) have proved to be valuable substitutes of conventional antibodies for molecular recognition. Their small size represents a precious advantage for rational mutagenesis based on modelling. Here we address the problem of predicting how Camelidae nanobody sequences can tolerate mutations by developing a simulation protocol based on all-atom molecular dynamics and whole-molecule docking. The method was tested on two sets of nanobodies characterized experimentally for their biophysical features. One set contained point mutations introduced to humanize a wild type sequence, in the second the CDRs were swapped between single-domain frameworks with Camelidae and human hallmarks. The method resulted in accurate scoring approaches to predict experimental yields and enabled to identify the structural modifications induced by mutations. This work is a promising tool for the in silico development of single-domain antibodies and opens the opportunity to customize single functional domains of larger macromolecules. PMID:27721441

  18. Molecular dynamics simulations and docking enable to explore the biophysical factors controlling the yields of engineered nanobodies

    Science.gov (United States)

    Soler, Miguel A.; De Marco, Ario; Fortuna, Sara

    2016-10-01

    Nanobodies (VHHs) have proved to be valuable substitutes of conventional antibodies for molecular recognition. Their small size represents a precious advantage for rational mutagenesis based on modelling. Here we address the problem of predicting how Camelidae nanobody sequences can tolerate mutations by developing a simulation protocol based on all-atom molecular dynamics and whole-molecule docking. The method was tested on two sets of nanobodies characterized experimentally for their biophysical features. One set contained point mutations introduced to humanize a wild type sequence, in the second the CDRs were swapped between single-domain frameworks with Camelidae and human hallmarks. The method resulted in accurate scoring approaches to predict experimental yields and enabled to identify the structural modifications induced by mutations. This work is a promising tool for the in silico development of single-domain antibodies and opens the opportunity to customize single functional domains of larger macromolecules.

  19. Capacity of graphite's layered structure to suppress the sputtering yield: A molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Jiting [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Zheng, Tao, E-mail: tzheng@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Yang, Jiangyan; Kong, Shuyan; Xue, Jianming; Wang, Yugang [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Nordlund, Kai [Department of Physics, University of Helsinki, P.O. Box 43, Helsinki 00014 (Finland)

    2015-05-15

    Highlights: • We simulated 20–120 keV C{sub 60} impact on carbon materials using MD method. • We found that small yield on graphite is mainly induced by its layered structure. • It is the first time that structure effect on sputtering is detailedly discussed. • Our results are consistent with previous experiments and simulations. - Abstract: 20–120 keV C{sub 60} bombardment on graphite and 20 keV C{sub 60} impact on diamond are studied by classical molecular dynamics (MD) simulations. The number of atoms ejected from graphite after a 20 keV C{sub 60} impact is found to be much smaller than that from diamond. By analyzing the microscopic sputtering process, we find this difference is due to the combined effects of graphite's low number density and layered structure. These two features of graphite make the pressure waves during the spike stage much weaker and the crater rim much more stable, compared to the case of diamond. While the role of atomic density on sputtering has been discussed in previous studies, effect of layered structure has not gained much attention yet. To affirm this effect and exclude the influence of density, we have also simulated C{sub 60} impact on an amorphous carbon (a-C) target whose density is very close to that of graphite. The yield of a-C is higher than that of graphite, certifying the capacity of graphite's layered structure to suppress the sputtering yield.

  20. A unified criterion for the growth and coalescence of microvoids

    Science.gov (United States)

    Morin, Léo; Leblond, Jean-Baptiste; Benzerga, A. Amine; Kondo, Djimédo

    2016-12-01

    A yield criterion is developed which unifies void growth and void coalescence theories. Standard void growth theory assumes that plastic flow is diffuse, if not prevalent everywhere within the matrix of the elementary cell considered. On the other hand, void coalescence theory assumes states of post-localized plasticity whereby plastic flow is restricted to intervoid ligaments. The new theory accommodates both scenarios through some appropriate choice of microscopic velocity fields. An important implication for actual evolution problems is a seamless transition from void growth to void coalescence. This is in contrast with previous hybrid approaches whereby abrupt transitions are associated with the presence of unavoidable corners in the effective yield surface. More generally, the new criterion is applicable to describe yielding in porous metal plasticity for both low and high void volume fractions.

  1. Validation of Criterion-Referenced Standards for Tests of Arm and Shoulder Girdle Strength and Endurance.

    Science.gov (United States)

    Rutherford, William J.; Corbin, Charles B.

    1994-01-01

    This study established criterion-referenced standards for selected tests of arm and shoulder girdle strength and endurance in college females. Tests of trained and untrained students using the contrasting groups method yielded criterion cutoff scores that classified subjects as trained or untrained based on upper arm and shoulder girdle resistance…

  2. Seasonal Influences on Milk Yield and Composition Dynamics during a Normal Lactation in Dairy Cows: Milk Yield, Fat and Protein Precentage

    Directory of Open Access Journals (Sweden)

    Simona Baul

    2014-05-01

    Full Text Available Researches were made on 125 lactations from Romanian Black Spotted cows and aimed to study the evolution of the interval between calving on milk yield and quality. Data were recorded and statistically analyzed by means of ANOVA / MANOVA determining the average values and dispersion indices. Based on averages parameters of lactation curves were calculated using the mathematical model called the incomplete gamma function.Cows that calved in winter and spring had steeper lactation curves for milk yield. The lactation curve for butter-fat percentage was significantly different (p<0.05 between summer-winter and summer-autumn seasons. Evolution of the lactation curve for protein percentage was significantly different (p<0.05 between winter and spring, distinct significant (p<0.01 between summer-autumn, winter-autumn and very significant (p<0.001 between spring and autumn.

  3. A Criterion for Regular Sequences

    Indian Academy of Sciences (India)

    D P Patil; U Storch; J Stückrad

    2004-05-01

    Let be a commutative noetherian ring and $f_1,\\ldots,f_r \\in R$. In this article we give (cf. the Theorem in $\\mathcal{x}$2) a criterion for $f_1,\\ldots,f_r$ to be regular sequence for a finitely generated module over which strengthens and generalises a result in [2]. As an immediate consequence we deduce that if $V(g_1,\\ldots,g_r) \\subseteq V(f_1,\\ldots,f_r)$ in Spec and if $f_1,\\ldots,f_r$ is a regular sequence in , then $g_1,\\ldots,g_r$ is also a regular sequence in .

  4. Formation Criterion for Synthetic Jets

    Science.gov (United States)

    2005-10-01

    formation data for the axisymmetric case were published over 50 years ago by Ingard and Labate.10 More recent studies33,34 suggest that L0/d > 1 for...with the axisymmetric data from Ingard and Labate10 and Smith et al.33 are compared in Fig. 7. It is found that the available data are consis- tent with...the jet formation criterion with an empirically determined constant K equal to approximately 0.16. The deviation of Ingard and Labate’s data at their

  5. Uncertainty Relation and Inseparability Criterion

    Science.gov (United States)

    Goswami, Ashutosh K.; Panigrahi, Prasanta K.

    2016-11-01

    We investigate the Peres-Horodecki positive partial transpose criterion in the context of conserved quantities and derive a condition of inseparability for a composite bipartite system depending only on the dimensions of its subsystems, which leads to a bi-linear entanglement witness for the two qubit system. A separability inequality using generalized Schrodinger-Robertson uncertainty relation taking suitable operators, has been derived, which proves to be stronger than the bi-linear entanglement witness operator. In the case of mixed density matrices, it identically distinguishes the separable and non separable Werner states.

  6. On the Modified Barkhausen Criterion

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.

    2016-01-01

    Oscillators are normally designed according to the Modified Barkhausen Criterion i.e. the complex pole pair is moved out in RHP so that the linear circuit becomes unstable. By means of the Mancini Phaseshift Oscillator it is demonstrated that the distortion of the oscillator may be minimized by i...... by introducing a nonlinear ”Hewlett Resistor” so that the complex pole-pair is in the RHP for small signals and in the LHP for large signals i.e. the complex pole pair of the instant linearized small signal model is moving around the imaginary axis in the complex frequency plane....

  7. Extended equal areas criterion: foundations and applications

    Energy Technology Data Exchange (ETDEWEB)

    Yusheng, Xue [Nanjim Automation Research Institute, Nanjim (China)

    1994-12-31

    The extended equal area criterion (EEAC) provides analytical expressions for ultra fast transient stability assessment, flexible sensitivity analysis, and means to preventive and emergency controls. Its outstanding performances have been demonstrated by thousands upon thousands simulations on more than 50 real power systems and by on-line operation records in an EMS environment of Northeast China Power System since September 1992. However, the researchers have mainly based on heuristics and simulations. This paper lays a theoretical foundation of EEAC and brings to light the mechanism of transient stability. It proves true that the dynamic EEAC furnishes a necessary and sufficient condition for stability of multi machine systems with any detailed models, in the sense of the integration accuracy. This establishes a new platform for further advancing EEAC and better understanding of problems. An overview of EEAC applications in China is also given in this paper. (author) 30 refs.

  8. Focusing criterion in DHM image reconstruction

    Science.gov (United States)

    Mihailescu, M.; Mihale, N.; Popescu, R. C.; Acasandrei, A.; Paun, I. A.; Dinescu, M.; Scarlat, E.

    2015-02-01

    This study is presenting the theoretical approach and the practical results of a precise activity involved in the hologram reconstruction in order to find the optimally focused image of MG63 osteoblast-like cells cultivated on polymeric flat substrates. The morphology and dynamic of the cell is investigated by digital holographic microscopy (DHM) technique. The reconstruction is digitally performed using an algorithm based on the scalar theory of diffraction in the Fresnel approximation. The quality of the 3D images of the cells is crucially depending on the focusing capability of the reconstruction chain to fit the parameters of the optical recorder, particularly the focusing value. Our proposal to find the focused image is based on the images decomposition on gray levels and their histogram analysis. More precisely the focusing criterion is based on the evaluation of the form of this distribution.

  9. Generalized cost-criterion-based learning algorithm for diagonal recurrent neural networks

    Science.gov (United States)

    Wang, Yongji; Wang, Hong

    2000-05-01

    A new generalized cost criterion based learning algorithm for diagonal recurrent neural networks is presented, which is with form of recursive prediction error (RPE) and has second convergent order. A guideline for the choice of the optimal learning rate is derived from convergence analysis. The application of this method to dynamic modeling of typical chemical processes shows that the generalized cost criterion RPE (QRPE) has higher modeling precision than BP trained MLP and quadratic cost criterion trained RPE (QRPE).

  10. Non-Equilibrium Gibbs' Criterion for Completely Wetting Volatile Liquids

    CERN Document Server

    Tsoumpas, Yannis; Galvagno, Mariano; Rednikov, Alexey; Ottevaere, Heidi; Thiele, Uwe; Colinet, Pierre

    2014-01-01

    During the spreading of a liquid over a solid substrate, the contact line can stay pinned at sharp edges until the contact angle exceeds a critical value. At (or sufficiently near) equilibrium, this is known as Gibbs' criterion. Here, we show both experimentally and theoretically that for completely wetting volatile liquids there also exists a dynamically-produced critical angle for depinning, which increases with the evaporation rate. This suggests that one may introduce a simple modification of the Gibbs' criterion for (de)pinning, that accounts for the non-equilibrium effect of evaporation.

  11. Dynamic optimization of artificial lighting in greenhouses.

    NARCIS (Netherlands)

    Heuvelink, E.; Challa, H.

    1989-01-01

    A principle for dynamic optimization of artificial lighting in greenhouses is presented, where the optimization criterion is maximization of the term yield minus related costs>. To this purpose it is important to consider the break-even point for artificial lighting, which can be defined a

  12. Evaluation of Biomass Yield and Water Treatment in Two Aquaponic Systems Using the Dynamic Root Floating Technique (DRF

    Directory of Open Access Journals (Sweden)

    Laura Silva

    2015-11-01

    Full Text Available The experiment evaluates the food production and water treatment of TAN, NO2−–N, NO3−–N, and PO43− in two aquaponics systems using the dynamic root floating technique (DRF. A separate recirculation aquaculture system (RAS was used as a control. The fish cultured was Nile tilapia (Oreochromis niloticus. The hydroponic culture in one treatment (PAK was pak choy (Brassica chinensis, and in the other (COR coriander (Coriandrum sativum. Initial and final weights were determined for the fish culture. Final edible fresh weight was determined for the hydroponic plant culture. TAN, NO2−–N, NO3−–N, and PO43− were measured in fish culture and hydroponic culture once a week at two times, morning (9:00 a.m. and afternoon (3:00 p.m.. The fish biomass production was not different in any treatment (p > 0.05 and the total plant yield was greater (p < 0.05 in PAK than in COR. For the hydroponic culture in the a.m., the PO43− was lower (p < 0.05 in the PAK treatment than in COR, and in the p.m. NO3−–N and PO43− were lower (p < 0.05 in PAK than in COR. The PAK treatment demonstrated higher food production and water treatment efficiency than the other two treatments.

  13. Dynamic Predictions of Crop Yield and Irrigation in Sub-Saharan Africa Due to Climate Change Impacts

    Science.gov (United States)

    Foster-Wittig, T.

    2012-12-01

    The highest damages from climate change are predicted to be in the agricultural sector in sub-Saharan Africa. Agriculture is predicted to be especially vulnerable in this region because of its current state of high temperature and low precipitation and because it is usually rain-fed or relies on relatively basic technologies which therefore limit its ability to sustain in increased poor climatic conditions [1]. The goal of this research is to quantify the vulnerability of this ecosystem by projecting future changes in agriculture due to IPCC predicted climate change impacts on precipitation and temperature. This research will provide a better understanding of the relationship between precipitation and rain-fed agriculture in savannas. In order to quantify the effects of climate change on agriculture, the impacts of climate change are modeled through the use of a land surface vegetation dynamics model previously developed combined with a crop model [2,4]. In this project, it will be used to model yield for point cropland locations within sub-Saharan Africa between Kenya and Botswana with a range of annual rainfall. With this model, future projections are developed for what can be anticipated for the crop yield based on two precipitation climate change scenarios; (1) decreased depth and (2) decreased frequency as well as temperature change scenarios; (3) only temperature increased, (4) temperature increase dand decreased precipitation depth, and (5) temperature increased and decreased precipitation frequency. Therefore, this will allow conclusions to be drawn about how mean precipitation and a changing climate effect food security in sub-Saharan Africa. As an additional analysis, irrigation is added to the model as it is thought to be the solution to protect food security by maximizing on the potential of food production. In water-limited areas such as Sub-Saharan Africa, it is important to consider water efficient irrigation techniques such as demand-based micro

  14. Using an Active-Optical Sensor to Develop an Optimal NDVI Dynamic Model for High-Yield Rice Production (Yangtze, China).

    Science.gov (United States)

    Liu, Xiaojun; Ferguson, Richard B; Zheng, Hengbiao; Cao, Qiang; Tian, Yongchao; Cao, Weixing; Zhu, Yan

    2017-03-24

    The successful development of an optimal canopy vegetation index dynamic model for obtaining higher yield can offer a technical approach for real-time and nondestructive diagnosis of rice (Oryza sativa L) growth and nitrogen (N) nutrition status. In this study, multiple rice cultivars and N treatments of experimental plots were carried out to obtain: normalized difference vegetation index (NDVI), leaf area index (LAI), above-ground dry matter (DM), and grain yield (GY) data. The quantitative relationships between NDVI and these growth indices (e.g., LAI, DM and GY) were analyzed, showing positive correlations. Using the normalized modeling method, an appropriate NDVI simulation model of rice was established based on the normalized NDVI (RNDVI) and relative accumulative growing degree days (RAGDD). The NDVI dynamic model for high-yield production in rice can be expressed by a double logistic model: RNDVI = ( 1 + e - 15.2829 × ( R A G D D i - 0.1944 ) ) - 1 - ( 1 + e - 11.6517 × ( R A G D D i - 1.0267 ) ) - 1 (R2 = 0.8577**), which can be used to accurately predict canopy NDVI dynamic changes during the entire growth period. Considering variation among rice cultivars, we constructed two relative NDVI (RNDVI) dynamic models for Japonica and Indica rice types, with R2 reaching 0.8764** and 0.8874**, respectively. Furthermore, independent experimental data were used to validate the RNDVI dynamic models. The results showed that during the entire growth period, the accuracy (k), precision (R2), and standard deviation of RNDVI dynamic models for the Japonica and Indica cultivars were 0.9991, 1.0170; 0.9084**, 0.8030**; and 0.0232, 0.0170, respectively. These results indicated that RNDVI dynamic models could accurately reflect crop growth and predict dynamic changes in high-yield crop populations, providing a rapid approach for monitoring rice growth status.

  15. Yield Improvement in Steel Casting (Yield II)

    Energy Technology Data Exchange (ETDEWEB)

    Richard A. Hardin; Christoph Beckermann; Tim Hays

    2002-02-18

    This report presents work conducted on the following main projects tasks undertaken in the Yield Improvement in Steel Casting research program: Improvement of Conventional Feeding and Risering Methods, Use of Unconventional Yield Improvement Techniques, and Case Studies in Yield Improvement. Casting trials were conducted and then simulated using the precise casting conditions as recorded by the participating SFSA foundries. These results present a statistically meaningful set of experimental data on soundness versus feeding length. Comparisons between these casting trials and casting trials performed more than forty years ago by Pellini and the SFSA are quite good and appear reasonable. Comparisons between the current SFSA feeding rules and feeding rules based on the minimum Niyama criterion reveal that the Niyama-based rules are generally less conservative. The niyama-based rules also agree better with both the trials presented here, and the casting trails performed by Pellini an d the SFSA years ago. Furthermore, the use of the Niyama criterion to predict centerline shrinkage for horizontally fed plate sections has a theoretical basis according to the casting literature reviewed here. These results strongly support the use of improved feeding rules for horizontal plate sections based on the Niyama criterion, which can be tailored to the casting conditions for a given alloy and to a desired level of soundness. The reliability and repeatability of ASTM shrinkage x-ray ratings was investigated in a statistical study performed on 128 x-rays, each of which were rated seven different times. A manual ''Feeding and Risering Guidelines for Steel Castings' is given in this final report. Results of casting trials performed to test unconventional techniques for improving casting yield are presented. These use a stacked arrangement of castings and riser pressurization to increase the casting yield. Riser pressurization was demonstrated to feed a casting up to

  16. Remote sensing and modelling of vegetation dynamics for early estimation and spatial analysis of grain yields in semiarid context in central Tunisia

    Science.gov (United States)

    Chahbi, Aicha; Zribi, Mehrez; Lili-Chabaane, Zohra

    2016-04-01

    In arid and semi-arid areas, population growth, urbanization, food security and climate change have an impact on agriculture in general and particular on the cereal production. Therefore to improve food security in arid countries, crop canopy monitoring and yield forecasting cereals are needed. Many models, based on the use of remote sensing or agro-meteorological models, have been developed to estimate the biomass and grain yield of cereals. Through the use of a rich database, acquired over a period of two years for more than 80 test fields, and from optical satellite SPOT/HRV images, the aim of the present study is to evaluate the feasibility of two yield prediction approaches. The first approach is based on the application of the semi-empirical growth model SAFY, developed to simulate the dynamics of the LAI and the grain yield, at the field scale. The model is able to reproduce the time evolution of the leaf area index of all fields with acceptable error. However, an inter-comparison between ground yield measurements and SAFY model simulations reveals that the yields are under-estimated by this model. We can explain the limits of the semi-empirical model SAFY by its simplicity and also by various factors that were not considered (fertilization, irrigation,...). To improve the yield estimation, a new approach is proposed: the grain yield is estimated in function of the LAI in the growth period between 25 March and 5 April. The LAI of this period is estimated by SAFY model. A linear relationship is developed between the measured grain yield and the LAI area of the maximum growth period.This approach is robust, the measured and estimated grain yields are well correlated. Following the validation of this approach, yield estimations are proposed for the entire studied site using the SPOT/HRV images.

  17. Yield formation and tillering dynamics of direct-seeded rice in flooded and nonflooded soils in the Huai River Basin of China

    NARCIS (Netherlands)

    Yan, J.; Yu, J.; Tao, G.C.; Vos, J.; Bouman, B.A.M.; Xie, G.H.; Meinke, H.B.

    2010-01-01

    Water shortage in the Huai River Basin prompts farmers to adopt water-saving technologies such as direct-seeded nonflooded or aerobic rice. Different cultivation practices impact on tiller growth and development. Improved insight into tiller dynamics is needed to increase yield in these production s

  18. A modified Burzynski criterion for anisotropic pressure-dependent materials

    Indian Academy of Sciences (India)

    FARZAD MOAYYEDIAN; MEHRAN KADKHODAYAN

    2017-01-01

    In this paper the Burzynski criterion, which was introduced for isotropic pressure-dependent materials, is modified for anisotropic pressure-dependent materials in plane-stress condition. The modified criterion can be calibrated with 10 experimental data points such as tensile stress at 0°, 45° and 90°, compressive stress at 0° and 90° and R-values in tensile stress at 0°, 45° and 90° from rolling direction and also biaxial tensilestress and tensile R-value. To identify the anisotropic parameters an error function is set up through comparison of the predicted yield stresses and R-values with those from experiments. Then the Downhill simplex method is applied to solve 10 high-nonlinearity equations. Finally, considering Al 2008-T4 (BCC), Al 2090-T3 (FCC),AZ31 (HCP) and also Mg–0.5% Th alloy, Mg–4% Li alloy, pure textured magnesium, textured magnesium andTi–4Al–1/4O2, which are HCP materials with ep¼ 1%; 5%; 10% as case studies and comparing the results for the modified Burzynski criterion with experiments, it is shown that the Burzynski criterion is appropriate for pressure-dependent anisotropic materials with proper accuracy.

  19. The past and future of modeling forest dynamics: from growth and yield curves to forest landscape models

    Science.gov (United States)

    Stephen R. Shifley; Hong S. He; Heike Lischke; Wen J. Wang; Wenchi Jin; Eric J. Gustafson; Jonathan R. Thompson; Frank R. Thompson; William D. Dijak; Jian Yang

    2017-01-01

    Context. Quantitative models of forest dynamics have followed a progression toward methods with increased detail, complexity, and spatial extent. Objectives. We highlight milestones in the development of forest dynamics models and identify future research and application opportunities. Methods. We reviewed...

  20. Criterion Referenced Measures for Clinical Evaluations.

    Science.gov (United States)

    Pikulski, John J.

    This paper discusses criterion referenced tests' characteristics and their use in clinical evaluation. The distinction between diagnostic tests and criterion referenced measures is largely a matter of emphasis. Some authorities believe that in diagnostic testing the emphasis is upon an evaluation of an individual's strengths and weaknesses in…

  1. ON A GENERALIZED GAUSS CONVERGENCE CRITERION

    Directory of Open Access Journals (Sweden)

    ILEANA BUCUR

    2015-07-01

    Full Text Available In this paper we combine the well known Raabe-Duhamel, Kummer, Bertrand . . . criterions of convergence for series with positive terms and we obtain a new one which is more powerful than those cited before. Even the famous Gauss criterion,which was in fact our starting point, is a consequence of this new convergence test.

  2. A Difference Criterion for Dimensionality Reduction

    Science.gov (United States)

    Aved, A. J.; Blasch, E.; Peng, J.

    2015-12-01

    A dynamic data-driven geoscience application includes hyperspectral scene classification which has shown promising potential in many remote-sensing applications. A hyperspectral image of a scene spectral radiance is typically measured by hundreds of contiguous spectral bands or features, ranging from visible/near-infrared (VNIR) to shortwave infrared (SWIR). Spectral-reflectance measurements provide rich information for object detection and classification. On the other hand, they generate a large number of features, resulting in a high dimensional measurement space. However, a large number of features often poses challenges and can result in poor classification performance. This is due to the curse of dimensionality which requires model reduction, uncertainty quantification and optimization for real-world applications. In such situations, feature extraction or selection methods play an important role by significantly reducing the number of features for building classifiers. In this work, we focus on efficient feature extraction using the dynamic data-driven applications systems (DDDAS) paradigm. Many dimension reduction techniques have been proposed in the literature. A well-known technique is Fisher's linear discriminant analysis (LDA). LDA finds the projection matrix that simultaneously maximizes a within class scatter matrix and minimizes a between class scatter matrix. However, LDA requires matrix inverse which can be a major issue when the within matrix is singular. We propose a difference criterion for dimension reduction that does not require a matrix inverse for software implementation. We show how to solve the optimization problem with semi-definite programming. In addition, we establish an error bound for the proposed algorithm. We demonstrate the connection between relief feature selection and a two class formulation of multi-class problems, thereby providing a sound basis for observed benefits associated with this formulation. Finally, we provide

  3. A novel stability criterion for interval time-delay chaotic systems via the evolutionary programming approach

    Energy Technology Data Exchange (ETDEWEB)

    Yan, J.-J. [Department of Computer and Communication, Shu-Te University, Kaohsiung 824, Taiwan (China)]. E-mail: jjyan@mail.stu.edu.tw; Hung, M.-L. [Department of Electrical Engineering, Far-East College, No. 49, Jung-Haw Road, Hsin-Shih Town, Tainan 744, Taiwan (China)

    2006-09-15

    This paper investigates a novel stability criterion for interval time-delay chaotic systems via the evolutionary programming (EP) approach. First a delay-dependent criterion is derived for ensuring the stability of degenerate time-delay systems, and then by solving eigenvalue location optimization problems, which will be defined later, the robust stability of interval time-delay systems can be guaranteed. An example is given to verify our method that yields less conservative results than those appeared in the literature.

  4. An improved criterion for Kapitza's pendulum stability

    Energy Technology Data Exchange (ETDEWEB)

    Butikov, Eugene i, E-mail: eugene.butikov@gmail.com [St. Petersburg State University, St. Petersburg (Russian Federation)

    2011-07-22

    An enhanced and more exact criterion for dynamic stabilization of the parametrically driven inverted pendulum is obtained: the boundaries of stability are determined with greater precision and are valid in a wider region of the system parameters than previous results. The lower boundary of stability is associated with the phenomenon of subharmonic resonances in this system. The relationship of the upper limit of dynamic stabilization of the inverted pendulum with ordinary parametric resonance (i.e. with destabilization of the lower equilibrium position) is established. Computer simulation of the physical system aids the analytical investigation and proves the theoretical results.

  5. A Non-Termination Criterion for Binary Constraint Logic Programs

    CERN Document Server

    Payet, Etienne

    2008-01-01

    On the one hand, termination analysis of logic programs is now a fairly established research topic within the logic programming community. On the other hand, non-termination analysis seems to remain a much less attractive subject. If we divide this line of research into two kinds of approaches: dynamic versus static analysis, this paper belongs to the latter. It proposes a criterion for detecting non-terminating atomic queries with respect to binary CLP rules, which strictly generalizes our previous works on this subject. We give a generic operational definition and an implemented logical form of this criterion. Then we show that the logical form is correct and complete with respect to the operational definition.

  6. Yield loss in apple caused by Monilinia fructigena (Aderh. & Rhul.) Honey, and spatio-temporal dynamics of disease development

    NARCIS (Netherlands)

    Leeuwen, van G.C.M.; Stein, A.; Holb, I.; Jeger, M.J.

    2000-01-01

    Monilinia fructigena (Aderh. & Ruhl.) Honey causes considerable yield losses in pome fruit culture. During a field study in the Netherlands in 1997 and 1998, the increase in disease incidence in time was assessed and final pre- and post-harvest losses were recorded in the susceptible apple culti

  7. Sweet potato yields and nutrient dynamics after short-term fallows in the humid lowlands of Papua New Guinea

    NARCIS (Netherlands)

    Hartemink, A.E.

    2003-01-01

    Shifting cultivation is common in the humid lowlands of Papua New Guinea but little is known about the effect of different fallows on sweet potato (Ipomoea batatas) yield and nutrient flows and pools in these systems. An experiment was conducted in which two woody fallow species (Piper aduncum and

  8. The 2005 and 2012 major drought events in Iberia: monitoring vegetation dynamics and crop yields using satellite data.

    Science.gov (United States)

    Gouveia, Célia M.; Trigo, Ricardo M.

    2014-05-01

    The Iberian Peninsula is recurrently affected by drought episodes and therefore by the adverse effects associated that range from severe water shortages to economic losses and related social impacts. During the hydrological years of 2004/2005 and 2011/2012, Iberia was hit by two of the worst drought episodes ever recording in this semi-arid region (Garcia-Herrera at al., 2007; Trigo et al., 2013). These two drought episodes were extreme in both its magnitude and spatial extent. A tendency towards a drier Mediterranean for the period 1970-2010 in comparison with 1901-70 has been identified (Hoerling et al., 2012), reinforcing the need for a continuous monitoring of vegetation stress and reliable estimates of the drought impacts. The strong effect of water scarcity on vegetation dynamics is well documented in Mediterranean and other semi-arid regions. Despite the usual link established between the decrease of vegetation greenness and the lack of precipitation during a considerably long period, the impact on vegetation activity may be amplified by other climatic anomalies, such as high temperature, high wind, and low relative humidity. The recent availability of consistent satellite imagery covering large regions over long periods of time has progressively reinforced the role of remote sensing in environmental studies, in particular in those related to drought episodes (e.g. Gouveia et al., 2009). The aim of the present work is to assess and monitor the cumulative impact over time of drought conditions on vegetation over Iberian Peninsula. For this purpose we have used the regional fields of the Normalized Difference Vegetation Index (NDVI) as obtained from the VEGETATION-SPOT5 instrument, from 1999 to 2013. The entire 15-yr long period was analysed, but particular attention was devoted to the two extreme drought episodes of 2004-2005 and 2011-2012. During the hydrological years of 2004-2005 and 2011-2012 drought episodes negative anomalies of NDVI were observed over

  9. Effect of Water Regime and Nitrogen Fertilisation on Growth Dynamics, Water Status and Yield of Burley Tobacco (Nicotianatabacum L.

    Directory of Open Access Journals (Sweden)

    Ruggiero C

    2014-12-01

    Full Text Available The results of a two-year research project into burley tobacco are reported and discussed. Three irrigation levels (40, 80 and 120% restitution of evapotranspiration (ET were factorially combined with four levels of nitrogen fertilisation (0, 80, 160 and 240 kg ha. Leaf area, leaf and stem dry matter and root development were measured. We monitored the water status of the 0-90 cm soil layer, the plants and stomatal resistance. Relations were also studied between leaf turgor pressure and plant growth, between the irrigation regime and plant water status, and between root and shoot development. Finally, water use efficiency (WUE and quality and quantity of cured leaves yields were evaluated. Nitrogen fertilisation did not affect plant water status, although it promoted plant growth, both in terms of leaf area and leaf and stem dry matter, and induced a yield increase in quantity and quality. Our trial showed little interaction between nitrogen fertilization level and water regime. Under such agronomic condition, the margins for increasing plant growth with nitrogen fertilization are limited, which is why application of nitrogen rates in excess of 160 kg haappear inadvisable. The difference in irrigation volumes led to a different soil water content which affected plant water status, stomatal functioning, plant growth, both in the roots and shoots, yield and quality of the cured leaves. The latter did not vary with the increase in water volume, while yield increased. Water use efficiency increased as the irrigation volume decreased and varied during the cropping cycle, increasing until early bloom, then decreasing. Relations between leaf turgor pressure and plant growth highlighted the different response of plants subjected to water stress compared with non-stressed plants.

  10. Application of a modified distributed-dynamic erosion and sediment yield model in a typical watershed of a hilly and gully region, Chinese Loess Plateau

    Science.gov (United States)

    Wu, Lei; Liu, Xia; Ma, Xiaoyi

    2016-11-01

    Soil erosion not only results in the destruction of land resources and the decline of soil fertility, but also contributes to river channel sedimentation. In order to explore the spatiotemporal evolution of erosion and sediment yield before and after returning farmland in a typical watershed of the hilly and gully region (Chinese Loess Plateau), a distributed-dynamic model of sediment yield based on the Chinese Soil Loss Equation (CSLE) was established and modified to assess the effects of hydrological factors and human activities on erosion and sediment yield between 1995 and 2013. Results indicate that (1) the modified model has the characteristics of a simple algorithm, high accuracy, wide practicability and easy expansion, and can be applied to predict erosion and sediment yield in the study area, (2) soil erosion gradations are closely related to the spatial distribution of rainfall erosivity and land use patterns, and the current soil and water conservation measures are not efficient for high rainfall intensities, and (3) the average sediment yield rate before and after model modification in the most recent 5 years (in addition to 2013) is 4574.62 and 1696.1 Mg km-2, respectively, decreasing by about 35.4 and 78.2 % when compared to the early governance (1995-1998). However, in July 2013 the once-in-a-century storm is the most important reason for maximum sediment yield. Results may provide an effective and scientific basis for soil and water conservation planning and ecological construction of the hilly and gully region, Chinese Loess Plateau.

  11. Effect of source/sink ratios on yield components, growth dynamics and structural characteristics of oil palm (Elaeis guineensis) bunches.

    Science.gov (United States)

    Pallas, Benoît; Mialet-Serra, Isabelle; Rouan, Lauriane; Clément-Vidal, Anne; Caliman, Jean-Pierre; Dingkuhn, Michael

    2013-04-01

    Source/sink ratios are known to be one of the main determinants of oil palm growth and development. A long-term experiment (9 years) was conducted in Indonesia on mature oil palms subjected to continuous bunch ablation and partial defoliation treatments to artificially modify source/sink ratios. During the experiment, all harvested bunches were dissected and phenological measurements were carried out to analyse the effect of source/sink ratios on yield components explaining variations in bunch number, the number of fruits per bunch and oil dry weight per fruit. An integrative variable (supply/demand ratio) describing the ratio between the assimilate supply from sources and the growing organ demand for carbohydrate was computed for each plant on a daily basis from observations of the number of developing organs and their sink strength, and of climate variables. Defoliation and bunch ablation affected the bunch number and the fruit number per bunch. Variations in bunch number per month were mainly due to variations in the fraction of aborted inflorescence and in the ratio between female and male inflorescences. Under fluctuating trophic conditions, variations in fruit number per bunch resulted both from changes in fruit-set and in the number of branches (rachillae) per inflorescence. For defoliated plants, the decrease in the number of developing reproductive sinks appeared to be sufficient to maintain fruit weight and oil concentration at the control level, without any major decrease in the concentration of non-structural carbohydrate reserves. Computation of the supply/demand ratio revealed that each yield component had a specific phase of sensitivity to supply/demand ratios during inflorescence development. Establishing quantitative relationships between supply/demand ratios, competition and yield components is the first step towards a functional model for oil palm.

  12. Dynamic and rate-dependent yielding behavior of Co{sub 0.9}Ni{sub 0.1} microcluster based magnetorheological fluids

    Energy Technology Data Exchange (ETDEWEB)

    Arief, Injamamul; Mukhopadhyay, P.K., E-mail: pkm@bose.res.in

    2016-01-01

    In this paper we performed steady shear and oscillatory magnetorheological (MR) studies in magnetic fluids containing CoNi sub-micron sized clusters of 450 nm in diameter. Such Co-rich nanoclusters were synthesized by conventional homogeneous nucleation without any external surfactant or reducing agent in liquid polyol at elevated temperature. The x-ray diffraction, energy dispersive x-ray analysis, scanning and transmission electron microscopy studies were done for analyzing the sample composition and morphology. Two variants of fluid samples were prepared by dispersing 15 vol% and 20 vol% of CoNi powders in castor oil. Room temperature steady magnetoshear studies indicate viscoplastic behavior with stronger dependence of static yield stress on magnetization than a dipolar coupling that was operational in the dynamic yield stress. Magnetosweep measurements at constant shear rate showed interesting viscous relaxation at high magnetic fields. We also explored dynamical elastic behavior through oscillatory magnetorheological studies under both strain sweep and frequency sweep modes, and showed glass transition like phenomenon occurring in them above critical shear amplitudes. - Highlights: • A typical polymer/surfactant free polyol reduction method was used to synthesize large-scale Co{sub 0.9}Ni{sub 0.1} nanoclusters. • Room temperature rate-dependent magnetorheology of CoNi-nanoclusters based MR fluids revealed viscoplastic behavior. • Magnetic fields were replaced by powder particle magnetization (M) for better yield stress scaling. • In addition to previously reported M{sup 2}-dependence, higher order relations (~M{sup 3}) were also noted for static yield stress. • An interesting viscous relaxation phenomenon occurred at higher magnetic fields.

  13. Filamentary and hierarchical pictures - Kinetic energy criterion

    Science.gov (United States)

    Klypin, Anatoly A.; Melott, Adrian L.

    1992-01-01

    We present a new criterion for formation of second-generation filaments. The criterion called the kinetic energy ratio, KR, is based on comparison of peculiar velocities at different scales. We suggest that the clumpiness of the distribution in some cases might be less important than the 'coldness' or 'hotness' of the flow for formation of coherent structures. The kinetic energy ratio is analogous to the Mach number except for one essential difference. If at some scale KR is greater than 1, as estimated at the linear stage, then when fluctuations of this scale reach nonlinearity, the objects they produce must be anisotropic ('filamentary'). In the case of power-law initial spectra the kinetic ratio criterion suggests that the border line is the power-spectrum with the slope n = -1.

  14. Aesthetical criterion in art and science

    CERN Document Server

    Milovanović, Miloš

    2016-01-01

    In the paper, the authors elaborate some recently published research concerning the originality of artworks in terms of self-organization in the complex systems physics. It has been demonstrated that the originality issue such conceived leads to the criterion of a substantial aesthetics whose applicability is not restricted to the fine arts domain only covering also physics, biology, cosmology and other fields construed in the complex systems terms. Moreover, it is about a truth criterion related to the traditional personality conception revealing the ontological context transcendent to the gnoseological dualism of subjective and objective reality that is characteristic of modern science and humanities. Thus, it is considered to be an aesthetical criterion substantiating art and science as well as the other developments of the postmodern era. Its impact to psychology, education, ecology, culture and other humanities is briefly indicated.

  15. Force criterion of different electrolytes in microchannel

    Institute of Scientific and Technical Information of China (English)

    Ren Yu-Kun; Yan Hui; Jiang Hong-Yuan; Gu Jian-Zhong; Antonio Ramos

    2009-01-01

    The control and handling of fluids is central to many applications of the lab-on-chip. This paper analyzes the basic theory of manipulating different electrolytes and finds the two-dimensional model. Coulomb force and dielectric force belonging to the body force of different electrolytes in the microchannel were analyzed. The force criterion at the interface was concluded, and testified by the specific example. Three basic equations were analyzed and applied to simulate the phenomenon. The force criterion was proved to be correct based on the simulation results.

  16. Fracture Criterion for Fracture Mechanics of Magnets

    Institute of Scientific and Technical Information of China (English)

    潘灏; 杨文涛

    2003-01-01

    The applicability and limitation of some fracture criteria in the fracture mechanics of magnets are studied.It is shown that the magnetic field intensity factor can be used as a fracture criterion when the crack in a magnet is only affected by a magnetic field. For some magnetostrictive materials in which the components of magnetostriction strain do not satisfy the compatibility equation of deformation, the stress intensity factor can no longer be effectively applicable as a fracture criterion when the crack in a magnet is affected by a magnetic field and mechanical loads simultaneously.

  17. Optimization of a Dynamic Hot Water Pretreatment of Switchgrass using Catalysis by Carbonation to Maximize Carbochemical Yields

    Science.gov (United States)

    Dhamdere, Rohit Tanaji

    A bio-refinery is a facility that converts renewable bio-resources into value-added chemicals and products. In this context of a bio-refinery, the production of the carbochemicals such as HMF, furfural and organic acids illustrate that multiple products can be produced from a renewable source such as lignocellulosic biomass (switchgrass). Traditionally, carbochemicals such as furfural and HMF are produced using inorganic acids such as H 2SO4, HCL, and H3PO4. The use of such acids requires the application of high cost materials of construction such as Hastelloy-C, titanium etc. The objective of this study is to develop a semi-continuous process for the conversion of switchgrass to carbochemicals such as HMF, furfural and organic acids. Moreover, the application of water as a green reaction medium and the utilization of carbonated water as a "green catalyst" were studied in this research. For the purpose of this study, we constructed a semi-continuous flow apparatus using three high precision Isco syringe pumps and a constant temperature oven to allow carbonation of the water over a range of temperatures and pressure to reactively pretreat switchgrass. Carbochemicals (furan-based aldehydes) and acids that were formed were detected using a Waters HPLC employing a Bio-Rad Aminex HPX-87H column with a PDA (photo diode array) detector at wavelengths range of 210 and 280nm. Oligosaccharides were detected using Dionex HPLC employing Bio-Rad Aminex HPX-87P column using a Shodex RI-101 refractive index detector. The kinetics of the formation and degradation of HMF and furfural were studied using the solver function in Microsoft Excel. Carbonated water clearly showed catalytic activity by increasing the yields of the HMF and furfural at temperatures of 220, 250 and 280°C. The highest catalytic activity was observed for HMF formation in carbonated water with a nine-fold increase in yields over that using neat subcritical water.

  18. Evaluation of Biomass Yield and Water Treatment in Two Aquaponic Systems Using the Dynamic Root Floating Technique (DRF)

    OpenAIRE

    Laura Silva; Eucario Gasca-Leyva; Edgardo Escalante; Kevin M Fitzsimmons; David Valdés Lozano

    2015-01-01

    The experiment evaluates the food production and water treatment of TAN, NO2−–N, NO3−–N, and PO43− in two aquaponics systems using the dynamic root floating technique (DRF). A separate recirculation aquaculture system (RAS) was used as a control. The fish cultured was Nile tilapia (Oreochromis niloticus). The hydroponic culture in one treatment (PAK) was pak choy (Brassica chinensis,) and in the other (COR) coriander (Coriandrum sativum). Initial and final weights were determined for the fis...

  19. An aerodynamic load criterion for airships

    Science.gov (United States)

    Woodward, D. E.

    1975-01-01

    A simple aerodynamic bending moment envelope is derived for conventionally shaped airships. This criterion is intended to be used, much like the Naval Architect's standard wave, for preliminary estimates of longitudinal strength requirements. It should be useful in tradeoff studies between speed, fineness ratio, block coefficient, structure weight, and other such general parameters of airship design.

  20. Stability Criterion for Discrete-Time Systems

    Directory of Open Access Journals (Sweden)

    K. Ratchagit

    2010-01-01

    Full Text Available This paper is concerned with the problem of delay-dependent stability analysis for discrete-time systems with interval-like time-varying delays. The problem is solved by applying a novel Lyapunov functional, and an improved delay-dependent stability criterion is obtained in terms of a linear matrix inequality.

  1. A Criterion-Referenced Test for Archery.

    Science.gov (United States)

    Shifflett, Bethany; Schuman, Barbara J.

    1982-01-01

    A criterion-referenced test for a beginning archery class was developed and evaluated. Techniques for estimating test validity and reliability were applied to data. A method developed by R. A. Burk (1976) was used to establish a cutoff score that would distinguish between those mastering the class and nonmasters. (Authors/PP)

  2. Luoyang Dual Spatial Criterion Ecological City Construction

    Institute of Scientific and Technical Information of China (English)

    Wang Fazeng; Wang Shengnan

    2007-01-01

    The construction of an ecological city has two foundational platforms:the small platform,namely urban district or simply called as"city ecosystem";and the big platform,namely around city district in certain region scope or also referred to as"city-region ecosystem".The construction of an ecological city must be launched in the dual spatial criteria:in city(urban district)criterion-optimizing the city ecosystem;in city-region(city territory)criterion-optimizing the city-region ecosystem.Luoyang has the bright characteristic and the typical image within cities of China,and even in the world.The construction of anecological city in dual spatial criteria-the city and the city-region-has the vital significance to urbanization advancement and sustainable development in Luoyang.In city-region criterion,the primary mission of Luoyang's ecological city construction is to create a fine ecological environment platform in its city territory.In city criterion,the basic duty of Luoyang's ecologic city construction is to enhance the ecological capacity and benefit of the central city.

  3. A focused information criterion for graphical models

    NARCIS (Netherlands)

    Pircalabelu, E.; Claeskens, G.; Waldorp, L.

    2015-01-01

    A new method for model selection for Gaussian Bayesian networks and Markov networks, with extensions towards ancestral graphs, is constructed to have good mean squared error properties. The method is based on the focused information criterion, and offers the possibility of fitting individual-tailore

  4. A Criterion for the Generalized Riemann Hypothesis

    Institute of Scientific and Technical Information of China (English)

    Jin Hong LI

    2009-01-01

    In this paper, we study the automorphic L-functions attached to the classical automorphic forms on GL(2), i.e. holomorphic cusp form. And we also give a criterion for the Generalized Riemann Hypothesis (GRH) for the above L-functions.

  5. Identical Synchronous Criterion for a Coupling System

    Institute of Scientific and Technical Information of China (English)

    HUANGXiangao; ANOWei; LUOXinmin; ZHUFuchen

    2004-01-01

    A new identical synchronous criterion of a coupling system, which is the time average of the derivative of the Lyapunov function, is proposed to determine the synchronous occurrence of any coupling system. Three examples with linear or nonlinear feedback synchronous systems are introduced to test some synchronous parameters that are the conditional Lyapunov exponents, the time average of the derivative of the Lyapunov function,the mean square error of the synchronization. Having obtained the synchronous parameters with the change of the feedback gains, we discover that Pecora and Carroll's criterion and He and Vaidya's reduced criterion are only fit to determine the synchronization of the identical selfsynchronization system which is a special example in the coupling systems, and are not taken as the general identical synchronous criterion of any coupling system. However,no matter whether the largest conditional Lyapunov exponent or the derivative of the Lyapunov function is positive or negative, synchronization of the coupling systems will occur,as long as the average change ratio of the derivative of the Lyapunov function tends to zero.

  6. Using a dynamic vegetation model for future projections of crop yields: application to Belgium in the framework of the VOTES and MASC projects

    Science.gov (United States)

    Jacquemin, Ingrid; Henrot, Alexandra-Jane; Fontaine, Corentin M.; Dendoncker, Nicolas; Beckers, Veronique; Debusscher, Bos; Tychon, Bernard; Hambuckers, Alain; François, Louis

    2016-04-01

    Dynamic vegetation models (DVM) were initially designed to describe the dynamics of natural ecosystems as a function of climate and soil, to study the role of the vegetation in the carbon cycle. These models are now directly coupled with climate models in order to evaluate feedbacks between vegetation and climate. But DVM characteristics allow numerous other applications, leading to amelioration of some of their modules (e.g., evaluating sensitivity of the hydrological module to land surface changes) and developments (e.g., coupling with other models like agent-based models), to be used in ecosystem management and land use planning studies. It is in this dynamic context about DVMs that we have adapted the CARAIB (CARbon Assimilation In the Biosphere) model. One of the main improvements is the implementation of a crop module, allowing the assessment of climate change impacts on crop yields. We try to validate this module at different scales: - from the plot level, with the use of eddy-covariance data from agricultural sites in the FLUXNET network, such as Lonzée (Belgium) or other Western European sites (Grignon, Dijkgraaf,…), - to the country level, for which we compare the crop yield calculated by CARAIB to the crop yield statistics for Belgium and for different agricultural regions of the country. Another challenge for the CARAIB DVM was to deal with the landscape dynamics, which is not directly possible due to the lack of consideration of anthropogenic factors in the system. In the framework of the VOTES and the MASC projects, CARAIB is coupled with an agent-based model (ABM), representing the societal component of the system. This coupled module allows the use of climate and socio-economic scenarios, particularly interesting for studies which aim at ensuring a sustainable approach. This module has particularly been exploited in the VOTES project, where the objective was to provide a social, biophysical and economic assessment of the ecosystem services in

  7. 3D homogenised strength criterion for masonry: Application to drystone retaining walls

    Science.gov (United States)

    Le, Hong Hanh; Garnier, Denis; Colas, Anne-Sophie; Terrade, Benjamin; Morel, Jean-Claude

    2016-10-01

    A 3D strength criterion for masonry is constructed based on yield design theory. Yield design homogenisation provides a rigorous theoretical framework to determine the yield strength properties of a periodic medium, based on the properties of its constituent materials. First, theoretical basis of 2D homogenisation of periodic media, and more particularly its application in the framework of yield design, will be retrieved. Then, 2D principles are extended to exhibit a 3D domain of running-bond masonry. This criterion is finally used to assess the stability of a drystone retaining wall loaded by an axle load, and theoretical results are compared to experimental data. Perspectives on this work are given as a conclusion.

  8. Improved similarity criterion for seepage erosion using mesoscopic coupled PFC-CFD model

    Institute of Scientific and Technical Information of China (English)

    倪小东; 王媛; 陈珂; 赵帅龙

    2015-01-01

    Conventional model tests and centrifuge tests are frequently used to investigate seepage erosion. However, the centrifugal test method may not be efficient according to the results of hydraulic conductivity tests and piping erosion tests. The reason why seepage deformation in model tests may deviate from similarity was first discussed in this work. Then, the similarity criterion for seepage deformation in porous media was improved based on the extended Darcy-Brinkman-Forchheimer equation. Finally, the coupled particle flow code–computational fluid dynamics (PFC−CFD) model at the mesoscopic level was proposed to verify the derived similarity criterion. The proposed model maximizes its potential to simulate seepage erosion via the discrete element method and satisfy the similarity criterion by adjusting particle size. The numerical simulations achieved identical results with the prototype, thus indicating that the PFC−CFD model that satisfies the improved similarity criterion can accurately reproduce the processes of seepage erosion at the mesoscopic level.

  9. A Brownian dynamic simulation to verify the effective hard-sphere model criterion for the formation of charged colloidal crystals%带电粒子形成胶体晶体的有效硬球模型判据的计算机模拟验证

    Institute of Scientific and Technical Information of China (English)

    顾凌云; 徐升华; 孙祉伟

    2011-01-01

    在对胶体晶体的研究中,带电粒子胶体晶体的形成机理比硬球胶体晶体更加复杂,对其形成条件目前还缺少有效的判断依据.有效硬球模型判据提出以有效直径作为判断参数.为了验证该判据的有效性,利用布朗动力学模拟研究了不同有效直径下带电粒子胶体晶体的特性.为了更加定量地研究单因素对带电胶体晶体形成的影响,取有效直径为2.8至0.8,并对一定的有效直径,研究了粒子几何直径和排斥力不同情况下的结晶行为.在布朗动力学模拟过程中,采用径向分布函数和键序参数方法检测体系的结构变化,并分析所形成的晶体结构.结果表明,在判断带电粒子胶体体系能否形成有序结构方面,有效硬球模型判据有一定的合理性.但是,并不能将有效直径作为唯一的判别参数,而是需要综合其他参数的影响,这显示出该判据的片面性.%The mechanism for the formation of colloidal crystals in charge-stabilized colloids is more complicated than that of hard-sphere colloidal crystals.And there is still lack of available criterion for the formation of charged colloidal crystals.The effective hard-sphere model suggests a criterion in which the effective diameter is used as a crucial parameter.In order to test the validity of this criterion,the characteristics of charged colloidal crystals with different effective diameters are investigated using Brownian dynamics simulations in this study.The crystallization behaviors with different geometric particle diameters and repulsive forces are also studied with some fixed effective diameters.In the simulation,the time evolution of crystallization process and the crystal structure during the simulation are characterized by means of the radial distribution functions and bond-order parameters.The results show that the effective hard-sphere model criterion has its reasonableness to some extent.However,the effective diameter cannot be

  10. Bridging AIC and BIC: a new criterion for autoregression

    OpenAIRE

    Jie Ding; Vahid Tarokh; Yuhong Yang

    2015-01-01

    We introduce a new criterion to determine the order of an autoregressive model fitted to time series data. It has the benefits of the two well-known model selection techniques, the Akaike information criterion and the Bayesian information criterion. When the data is generated from a finite order autoregression, the Bayesian information criterion is known to be consistent, and so is the new criterion. When the true order is infinity or suitably high with respect to the sample size, the Akaike ...

  11. A critical analysis of the Mises stress criterion used in frequency domain fatigue life prediction

    Directory of Open Access Journals (Sweden)

    Adam Niesłony

    2016-10-01

    Full Text Available Multiaxial fatigue failure criteria are formulated in time and frequency domain. The number of frequency domain criteria is rather small and the most popular one is the equivalent von Mises stress criterion. This criterion was elaborated by Preumont and Piefort on the basis of well-known von Mises stress concept, first proposed by Huber in 1907, and well accepted by the scientific community and engineers. It is important to know, that the criterion was developed to determine the yield stress and material effort under static load. Therefore the direct use of equivalent von Mises stress criterion for fatigue life prediction can lead to some incorrectness of theoretical and practical nature. In the present study four aspects were discussed: influence of the value of fatigue strength of tension and torsion, lack of parallelism of the SN curves, abnormal behaviour of the criterion under biaxial tensioncompression and influence of phase shift between particular stress state components. Information contained in this article will help to prevent improper use of this criterion and contributes to its better understanding

  12. Pore-scale dynamics of enzyme adsorption, swelling and reactive dissolution determine sugar yield in hemicellulose hydrolysis for biofuel production

    Science.gov (United States)

    Dutta, Sajal Kanti; Chakraborty, Saikat

    2016-12-01

    Hemicelluloses are the earth’s second most abundant structural polymers, found in lignocellulosic biomass. Efficient enzymatic depolymerization of xylans by cleaving their β-(1 → 4)-glycosidic bonds to produce soluble sugars is instrumental to the cost-effective production of liquid biofuels. Here we show that the multi-scale two-phase process of enzymatic hydrolysis of amorphous hemicelluloses is dominated by its smallest scale-the pores. In the crucial first five hours, two to fourfold swelling of the xylan particles allow the enzymes to enter the pores and undergo rapid non-equilibrium adsorption on the pore surface before they hydrolyze the solid polymers, albeit non-competitively inhibited by the products xylose and xylobiose. Rapid pore-scale reactive dissolution increases the solid carbohydrate’s porosity to 80-90%. This tightly coupled experimental and theoretical study quantifies the complex temporal dynamics of the transport and reaction processes coupled across scales and phases to show that this unique pore-scale phenomenon can be exploited to accelerate the depolymerization of hemicelluloses to monomeric sugars in the first 5-6 h. We find that an ‘optimal substrate loading’ of 5 mg/ml (above which substrate inhibition sets in) accelerates non-equilibrium enzyme adsorption and solid hemicellulose depolymerization at the pore-scale, which contributes three-quarters of the soluble sugars produced for bio-alcohol fermentation.

  13. Photodissociation of ketene: CH{sub 2}CO {yields} CH{sub 2}(a{sup 1}A{sub 1}) + CO(v=1) rates and dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Wade, E.A.

    1996-12-01

    The rotational energy release in the dissociation of ketene (CH{sub 2}CO) along its singlet potential energy surface is observed and compared with several statistical and dynamical theories. Rotational distributions for the product, CO(X{sup 1}{Sigma}+)(v=1), are measured from the threshold for production of CH{sub 2}(a {sup 1}A{sub 1}) (0,0,0) + CO(X{sup 1}{Sigma}+)(v=1) to 1720 cm{sup -1} above. Near threshold (E{le} 200 cm{sup -1} over threshold), phase space theory (PST) matches the observed distributions. At 357 and 490 cm{sup -1}, PST constrained by the measured state distributions of the methylene fragment, provides a good fit to these CO(v=1) rotational distributions. For E > 490 cm{sup -1}, the constrained PST matches the average rotational energy observed but predicts distributions which are broader than observed. This contrasts to the rotational distributions of the {sup 1}CH{sub 2} fragment which become shifted to lower rotational states than PST as energy increases from 200 cm{sup -1} above threshold. Dynamical models, the impulsive model and Franck-Condon mapping, do not account for the product rotational state distributions. The CO(v=1) rotational distributions for E > 200 cm{sup -1} contain no measurable product from triplet channel fragmentation. Therefore, they can be compared with the previously determined CO(v=0) rotational distributions in order to partition the CO(v=0) yield between singlet and triplet channels and recalculate the singlet yield. This new yield is found to be at the upper limits of the range previously reported. Rate constants and quantum yields have been determined for the photodissociation of ketene to produce CH{sub 2}(a {sup 1}A{sub 1}) (0,0,0) + CO(X {sup 1}{Sigma}+)(v=1). At 57, 110, 200, 357, and 490 cm{sup -1} above this product threshold, vibrational branching ratios for the singlet products were measured and compared to phase space theory (PST), separate statistical ensembles (SSE), and variational RRKM (var. RRKM).

  14. Analytical criterion for porous solids containing cylindrical voids in an incompressible matrix exhibiting tension-compression asymmetry

    Science.gov (United States)

    Cazacu, Oana; Stewart, Joel B.

    2013-05-01

    A new analytic plastic potential is developed using a rigorous limit analysis approach. Conditions of homogeneous boundary strain rate are imposed on every cylinder concentric with the cavity. It is shown that, due to the tension-compression asymmetry of the incompressible matrix, the third invariant of the stress deviator has a strong influence on the yielding of the porous solid. New and intriguing results are obtained; namely, for axisymmetric loadings and plane strain conditions, the stress state at yielding is not hydrostatic. In the case when the matrix has the same yield in tension as in compression, the new criterion reduces to Gurson's criterion for cylindrical voids.

  15. Information criterion based fast PCA adaptive algorithm

    Institute of Scientific and Technical Information of China (English)

    Li Jiawen; Li Congxin

    2007-01-01

    The novel information criterion (NIC) algorithm can find the principal subspace quickly, but it is not an actual principal component analysis (PCA) algorithm and hence it cannot find the orthonormal eigen-space which corresponds to the principal component of input vector.This defect limits its application in practice.By weighting the neural network's output of NIC, a modified novel information criterion (MNIC) algorithm is presented.MNIC extractes the principal components and corresponding eigenvectors in a parallel online learning program, and overcomes the NIC's defect.It is proved to have a single global optimum and nonquadratic convergence rate, which is superior to the conventional PCA online algorithms such as Oja and LMSER.The relationship among Oja, LMSER and MNIC is exhibited.Simulations show that MNIC could converge to the optimum fast.The validity of MNIC is proved.

  16. Sampling Criterion for EMC Near Field Measurements

    DEFF Research Database (Denmark)

    Franek, Ondrej; Sørensen, Morten; Ebert, Hans;

    2012-01-01

    An alternative, quasi-empirical sampling criterion for EMC near field measurements intended for close coupling investigations is proposed. The criterion is based on maximum error caused by sub-optimal sampling of near fields in the vicinity of an elementary dipole, which is suggested as a worst......-case representative of a signal trace on a typical printed circuit board. It has been found that the sampling density derived in this way is in fact very similar to that given by the antenna near field sampling theorem, if an error less than 1 dB is required. The principal advantage of the proposed formulation is its...... parametrization with respect to the desired maximum error in measurements. This allows the engineer performing the near field scan to choose a suitable compromise between accuracy and measurement time....

  17. Optimization of laminates subjected to failure criterion

    Directory of Open Access Journals (Sweden)

    E. Kormaníková

    2011-01-01

    Full Text Available The paper is aimed on laminate optimization subjected to maximum strain criterion. The optimization problem is based on the use of continuous design variables. The thicknesses of layers with the known orientation are used as design variables. The optimization problem with strain constraints are formulated to minimize the laminate weight. The design of the final thickness is rounded off to integer multiples of the commercially available layer thickness.

  18. Age Effects in Adaptive Criterion Learning.

    Science.gov (United States)

    Cassidy, Brittany S; Gutchess, Angela H

    2016-11-01

    Although prior work has examined age-related changes to criterion placement and flexibility, no study tested these constructs through a paradigm that employs adaptive feedback to encourage specific criterion changes. The goal of this study was to assess age differences in how young and older adults adapt and shift criteria in recognition memory decisions based on trial-by-trial feedback. Young and older adults completed an adaptive criterion learning paradigm. Over 3 study/test cycles, a biased feedback technique at test encouraged more liberal or strict responding by false-positive feedback toward false alarms or misses. Older adults were more conservative than young, even when feedback first encouraged a liberal response bias, and older adults adaptively placed criteria in response to biased feedback, much like young adults. After first being encouraged to respond conservatively, older adults shifted criteria less than young when feedback encouraged more lenient responding. These findings evidence labile adaptive criteria placement and criteria shifting with age. However, age-related tendencies toward conservative response biases may limit the extent to which criteria can be shifted in a lenient direction. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. An information criterion for marginal structural models.

    Science.gov (United States)

    Platt, Robert W; Brookhart, M Alan; Cole, Stephen R; Westreich, Daniel; Schisterman, Enrique F

    2013-04-15

    Marginal structural models were developed as a semiparametric alternative to the G-computation formula to estimate causal effects of exposures. In practice, these models are often specified using parametric regression models. As such, the usual conventions regarding regression model specification apply. This paper outlines strategies for marginal structural model specification and considerations for the functional form of the exposure metric in the final structural model. We propose a quasi-likelihood information criterion adapted from use in generalized estimating equations. We evaluate the properties of our proposed information criterion using a limited simulation study. We illustrate our approach using two empirical examples. In the first example, we use data from a randomized breastfeeding promotion trial to estimate the effect of breastfeeding duration on infant weight at 1 year. In the second example, we use data from two prospective cohorts studies to estimate the effect of highly active antiretroviral therapy on CD4 count in an observational cohort of HIV-infected men and women. The marginal structural model specified should reflect the scientific question being addressed but can also assist in exploration of other plausible and closely related questions. In marginal structural models, as in any regression setting, correct inference depends on correct model specification. Our proposed information criterion provides a formal method for comparing model fit for different specifications.

  20. Regularization Parameter Selections via Generalized Information Criterion.

    Science.gov (United States)

    Zhang, Yiyun; Li, Runze; Tsai, Chih-Ling

    2010-03-01

    We apply the nonconcave penalized likelihood approach to obtain variable selections as well as shrinkage estimators. This approach relies heavily on the choice of regularization parameter, which controls the model complexity. In this paper, we propose employing the generalized information criterion (GIC), encompassing the commonly used Akaike information criterion (AIC) and Bayesian information criterion (BIC), for selecting the regularization parameter. Our proposal makes a connection between the classical variable selection criteria and the regularization parameter selections for the nonconcave penalized likelihood approaches. We show that the BIC-type selector enables identification of the true model consistently, and the resulting estimator possesses the oracle property in the terminology of Fan and Li (2001). In contrast, however, the AIC-type selector tends to overfit with positive probability. We further show that the AIC-type selector is asymptotically loss efficient, while the BIC-type selector is not. Our simulation results confirm these theoretical findings, and an empirical example is presented. Some technical proofs are given in the online supplementary material.

  1. Social influences on adaptive criterion learning.

    Science.gov (United States)

    Cassidy, Brittany S; Dubé, Chad; Gutchess, Angela H

    2015-07-01

    People adaptively shift decision criteria when given biased feedback encouraging specific types of errors. Given that work on this topic has been conducted in nonsocial contexts, we extended the literature by examining adaptive criterion learning in both social and nonsocial contexts. Specifically, we compared potential differences in criterion shifting given performance feedback from social sources varying in reliability and from a nonsocial source. Participants became lax when given false positive feedback for false alarms, and became conservative when given false positive feedback for misses, replicating prior work. In terms of a social influence on adaptive criterion learning, people became more lax in response style over time if feedback was provided by a nonsocial source or by a social source meant to be perceived as unreliable and low-achieving. In contrast, people adopted a more conservative response style over time if performance feedback came from a high-achieving and reliable source. Awareness that a reliable and high-achieving person had not provided their feedback reduced the tendency to become more conservative, relative to those unaware of the source manipulation. Because teaching and learning often occur in a social context, these findings may have important implications for many scenarios in which people fine-tune their behaviors, given cues from others.

  2. Effects of arbuscular mycorrhizae on tomato yield, nutrient uptake, water relations, and soil carbon dynamics under deficit irrigation in field conditions.

    Science.gov (United States)

    Bowles, Timothy M; Barrios-Masias, Felipe H; Carlisle, Eli A; Cavagnaro, Timothy R; Jackson, Louise E

    2016-10-01

    Plant strategies to cope with future droughts may be enhanced by associations between roots and soil microorganisms, including arbuscular mycorrhizal (AM) fungi. But how AM fungi affect crop growth and yield, together with plant physiology and soil carbon (C) dynamics, under water stress in actual field conditions is not well understood. The well-characterized mycorrhizal tomato (Solanum lycopersicum L.) genotype 76R (referred to as MYC+) and the mutant nonmycorrhizal tomato genotype rmc were grown in an organic farm with a deficit irrigation regime and control regime that replaced evapotranspiration. AM increased marketable tomato yields by ~25% in both irrigation regimes but did not affect shoot biomass. In both irrigation regimes, MYC+ plants had higher plant nitrogen (N) and phosphorus (P) concentrations (e.g. 5 and 24% higher N and P concentrations in leaves at fruit set, respectively), 8% higher stomatal conductance (gs), 7% higher photosynthetic rates (Pn), and greater fruit set. Stem water potential and leaf relative water content were similar in both genotypes within each irrigation regime. Three-fold higher rates of root sap exudation in detopped MYC+ plants suggest greater capacity for water uptake through osmotic driven flow, especially in the deficit irrigation regime in which root sap exudation in rmc was nearly absent. Soil with MYC+ plants also had slightly higher soil extractable organic C and microbial biomass C at anthesis but no changes in soil CO2 emissions, although the latter were 23% lower under deficit irrigation. This study provides novel, field-based evidence for how indigenous AM fungi increase crop yield and crop water use efficiency during a season-long deficit irrigation and thus play an important role in coping with increasingly limited water availability in the future.

  3. Isobaric yield ratio difference between the 140 $A$ MeV $^{58, 64}$Ni + $^{9}$Be reactions studied by antisymmetric molecular dynamics model

    CERN Document Server

    Qiao, C Y; Ma, C W; Zhang, Y L; Wang, S S

    2015-01-01

    \\item[Background] The isobaric yield ratio difference (IBD) method is found to be sensitive to the density difference of neutron-rich nucleus induced reaction around the Fermi energy. \\item[Purpose] An investigation is performed to study the IBD results in the transport model. \\item[Methods] The antisymmetric molecular dynamics (AMD) model plus the sequential decay model GEMINI are adopted to simulate the 140$A$ MeV $^{58, 64}$Ni + $^{9}$Be reactions. A relative small coalescence radius R$_c =$ 2.5 fm is used for the phase space at $t =$ 500 fm/c to form the hot fragment. Two limitations on the impact parameter ($b1 = 0 - 2$ fm and $b2 = 0 - 9$ fm) are used to study the effect of central collisions in IBD. \\item[Results] The isobaric yield ratios (IYRs) for the large--$A$ fragments are found to be suppressed in the symmetric reaction. The IBD results for fragments with neutron-excess $I = $ 0 and 1 are obtained. A small difference is found in the IBDs with the $b1$ and $b2$ limitations in the AMD simulated re...

  4. Some remarks on Relativistic Diffusion and the Spectral Dimension Criterion

    CERN Document Server

    Muniz, C R; Filho, R N Costa; Bezerra, V B

    2014-01-01

    The spectral dimension $d_s$ for high energies is calculated using the Relativistic Schr\\"{o}dinger Equation Analytically Continued (RSEAC) instead of the so-called Telegraph's Equation (TE), in both ultraviolet (UV) and infrared (IR) regimens. Regarding the TE, the recent literature presents difficulties related to its stochastic derivation and interpretation, advocating the use of the RSEAC to properly describe the relativistic diffusion phenomena. Taking into account that the Lorentz symmetry is broken in UV regime at Lifshitz point, we show that there exists a degeneracy in very high energies, meaning that both the RSEAC and the TE correctly describe the diffusion processes at these energy scales, at least under the spectral dimension criterion. In fact, both the equations yield the same result, namely, $d_s = 2$, a dimensional reduction that is compatible with several theories of quantum gravity. This result is reached even when one takes into account a cosmological model - the De Sitter one - for a flat...

  5. Q criterion for disc stability modified by external tidal field

    CERN Document Server

    Jog, Chanda J

    2013-01-01

    The standard Q criterion (with Q > 1) describes the local stability of a disc supported by rotation and random motion. Most astrophysical discs, however, are under the influence of an external gravitational field which can affect their stability. A typical example is a galactic disc embedded in a dark matter halo. Here we do a linear perturbation analysis for a disc in an external field, and obtain a generalized dispersion relation and a modified stability criterion. An external field has two effects on the disc dynamics: first, it contributes to the unperturbed rotational field, and second, it adds a tidal field term in the stability parameter. A typical disruptive tidal field results in a higher modified Q value and hence leads to a more stable disc. We apply these results to the Milky Way, and to a low surface brightness galaxy UGC 7321. We find that in each case the stellar disc by itself is barely stable and it is the dark matter halo that stabilizes the disc against local, axisymmetric gravitational ins...

  6. A Criterion Based on Closed-loop Pilot-aircraft Systems for Predicting Flying Qualities

    Institute of Scientific and Technical Information of China (English)

    Tan Wenqian; A.V.Efremov; Qu Xiangju

    2010-01-01

    During the process of aircraft design,the mathematical model of pilot control behavior characteristics is always used to predict aircraft flying qualities (FQ).This is one of the important methods to avoid pilot-aircraft adverse coupling.In order to study the FQ criterion based on closedloop pilotaircraft systems,first,an experimental database is built,which includes 40 aircraft dynamics configurations and the corresponding flight simulation results.Second,the mathematical pilot models with a set of different aircraft configurations are obtained by this experimental database.Then,two FQ criteria,NealSmith criterion and Moscow Aviation Institute (MAI) criterion,are analyzed.And the relationship between the FQ level evaluated by actual pilot and the parameters of closedloop pilotaircraft systems is studied.Finally,an improved criterion of aircraft FQ is built based on the above two criteria.This new criterion is further used to predict FQ for four new aircraft dynamics configurations,and the prediction results verify its accuracy and practicability.

  7. Mean-square convergence analysis of ADALINE training with minimum error entropy criterion.

    Science.gov (United States)

    Chen, Badong; Zhu, Yu; Hu, Jinchun

    2010-07-01

    Recently, the minimum error entropy (MEE) criterion has been used as an information theoretic alternative to traditional mean-square error criterion in supervised learning systems. MEE yields nonquadratic, nonconvex performance surface even for adaptive linear neuron (ADALINE) training, which complicates the theoretical analysis of the method. In this paper, we develop a unified approach for mean-square convergence analysis for ADALINE training under MEE criterion. The weight update equation is formulated in the form of block-data. Based on a block version of energy conservation relation, and under several assumptions, we carry out the mean-square convergence analysis of this class of adaptation algorithm, including mean-square stability, mean-square evolution (transient behavior) and the mean-square steady-state performance. Simulation experimental results agree with the theoretical predictions very well.

  8. The Weierstrass Criterion and the Lemaitre-Tolman-Bondi Models with Cosmological Constant \\lambda

    CERN Document Server

    Bochicchio, Ivana; Laserra, Ettore

    2011-01-01

    We analyze Lemaitre-Tolman-Bondi models in presence of the cosmological constant \\Lambda through the classical Weierstrass criterion. Precisely, we show that the Weierstrass approach allows us to classify the dynamics of these inhomogeneous spherically symmetric Universes taking into account their relationship with the sign of \\Lambda.

  9. Beating the Stoner criterion using molecular interfaces

    Science.gov (United States)

    Ma'Mari, Fatma Al; Moorsom, Timothy; Teobaldi, Gilberto; Deacon, William; Prokscha, Thomas; Luetkens, Hubertus; Lee, Steve; Sterbinsky, George E.; Arena, Dario A.; MacLaren, Donald A.; Flokstra, Machiel; Ali, Mannan; Wheeler, May C.; Burnell, Gavin; Hickey, Bryan J.; Cespedes, Oscar

    2015-08-01

    Only three elements are ferromagnetic at room temperature: the transition metals iron, cobalt and nickel. The Stoner criterion explains why iron is ferromagnetic but manganese, for example, is not, even though both elements have an unfilled 3d shell and are adjacent in the periodic table: according to this criterion, the product of the density of states and the exchange integral must be greater than unity for spontaneous spin ordering to emerge. Here we demonstrate that it is possible to alter the electronic states of non-ferromagnetic materials, such as diamagnetic copper and paramagnetic manganese, to overcome the Stoner criterion and make them ferromagnetic at room temperature. This effect is achieved via interfaces between metallic thin films and C60 molecular layers. The emergent ferromagnetic state exists over several layers of the metal before being quenched at large sample thicknesses by the material's bulk properties. Although the induced magnetization is easily measurable by magnetometry, low-energy muon spin spectroscopy provides insight into its distribution by studying the depolarization process of low-energy muons implanted in the sample. This technique indicates localized spin-ordered states at, and close to, the metal-molecule interface. Density functional theory simulations suggest a mechanism based on magnetic hardening of the metal atoms, owing to electron transfer. This mechanism might allow for the exploitation of molecular coupling to design magnetic metamaterials using abundant, non-toxic components such as organic semiconductors. Charge transfer at molecular interfaces may thus be used to control spin polarization or magnetization, with consequences for the design of devices for electronic, power or computing applications (see, for example, refs 6 and 7).

  10. Convex functions and the rolling circle criterion

    OpenAIRE

    1995-01-01

    Given 0≤R1≤R2≤∞, CVG(R1,R2) denotes the class of normalized convex functions f in the unit disc U, for which ∂f(U) satisfies a Blaschke Rolling Circles Criterion with radii R1 and R2. Necessary and sufficient conditions for R1=R2, growth and distortion theorems for CVG(R1,R2) and rotation theorem for the class of convex functions of bounded type, are found.

  11. Early Stop Criterion from the Bootstrap Ensemble

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Larsen, Jan; Fog, Torben L.

    1997-01-01

    This paper addresses the problem of generalization error estimation in neural networks. A new early stop criterion based on a Bootstrap estimate of the generalization error is suggested. The estimate does not require the network to be trained to the minimum of the cost function, as required...... by other methods based on asymptotic theory. Moreover, in contrast to methods based on cross-validation which require data left out for testing, and thus biasing the estimate, the Bootstrap technique does not have this disadvantage. The potential of the suggested technique is demonstrated on various time...

  12. A CRITERION FOR TESTING WHETHER A DIFFERENCE IDEAL IS PRIME

    Institute of Scientific and Technical Information of China (English)

    Chunming YUAN; Xiao-Shan GAO

    2009-01-01

    This paper presents a criterion for testing the irreducibility of a polynomial over an algebraic extension field. Using this criterion and the characteristic set method, the authors give a criterion for testing whether certain difference ascending chains are strong irreducible, and as a consequence, whether the saturation ideals of these ascending chains are prime ideals.

  13. Condensation of saturated vapours on isentropic compression: a simple criterion

    Energy Technology Data Exchange (ETDEWEB)

    Patwardhan, V.S.

    1987-01-01

    A criterion is derived and tested for determining whether the isentropic compression of saturated vapours leads to superheat or condensation. This criterion needs only values of the critical temperature, the acentric factor and the liquid specific heat. The application of the criterion for selection of a working fluid both for heat pumps and heat engines is discussed.

  14. Position Mooring Control Based on a Structural Reliability Criterion

    DEFF Research Database (Denmark)

    Fang, Shaoji; Leira, Bernt J.; Blanke, Mogens

    2013-01-01

    is achieved using structural reliability indices in a cost function, where both the mean mooring-line tension and dynamic effects are considered. An optimal set-point is automatically produced without need for manual interaction. The parameters of the extreme value distribution are calculated on-line thereby...... adapting the set-point calculations to the prevailing environment. In contrast to earlier approaches, several mooring line are simultaneously accounted for by the algorithm, not only the most critical one. Detailed simulations illustrate the features of the new method and it is shown that the structural...... reliability criterion based algorithm ensures the safety of mooring lines in a variety of external environmental conditions and also in situations of failure of a single line....

  15. Effect of composts on microbial dynamics and activity, dry root rot severity and seed yield of cowpea in the Indian arid region

    Directory of Open Access Journals (Sweden)

    Meenu BAREJA

    2011-01-01

    Full Text Available Nutrient-deficient sandy soil, having poor moisture retention, favors  Macrophomina phaseolina, a soil-borne plant pathogen, occurring in severe form on many important crops grown in the Indian arid region. In a 2-year field experiment, five composts (4 ton/ha prepared from residues of Calotropis procera, Prosopis juliflora, Azadirachta indica, Acacia nilotica, and on-farm weeds were tested on cowpea (Vigna unguiculata to determine their effectiveness in limiting the  severity of charcoal rot caused by M. phaseolina in relation to the microbial population dynamics, microbial activity and the seed yield of cowpea.  In general, compost-amended plots retained 8.9% higher moisture than unamended plots. The microbial population increased in amended plots during the crop season. Populations of total fungi and actinomycetes were heighest in Calotropis compost-amended soil, while total bacteria were maximum in weed- compost amended soil. Microbial activity in amended plots was  26.3% higher than in unamended plots. Among trace elements,  uptake of Zn, Mn, Fe and Cu was  heighest  in plants grown in weed-compost amended soil followed by A. nilotica compost-amended soil. Soil amendment with the composts significantly reduced  plant mortality due to charcoal rot. The lowest mortality was recorded in plants amended with A. nilotica compost (5.5% followed by P. juliflora compost (5.8, while the  highest plant mortality (11.5% from charcoal rot occurred in the unamended control on the basis of the pooled average of two years. There was a significant inverse correlation between microbial activity and charcoal rot incidence in cowpea at 20 days after planting. Composts also had a beneficial effect on yield, with a 28.3% increase in seed yield in P. juliflora compost-amended plots. These results suggest that in resource-deficient farming , certain on-farm wastes can be effectively utilized for managing soil-borne pathogens, as well as  for

  16. Viability decision of linear discrete-time stochastic systems with probability criterion

    Institute of Scientific and Technical Information of China (English)

    Wansheng TANG; Jun ZHENG; Jianxiong ZHANG

    2009-01-01

    In this paper,the optimal viability decision problem of linear discrete-time stochastic systems with probability criterion is investigated.Under the condition of sequence-reachable discrete-time dynamic systems,the existence theorem of optimal viability strategy is given and the solving procedure of the optimal strategy is provided based on dynamic programming.A numerical example shows the effectiveness of the proposed methods.

  17. Kinematic criterion for breaking of shoaling waves

    Science.gov (United States)

    Liberzon, Dan; Itay, Uri

    2016-11-01

    Validity of a kinematic criterion for breaking of shoaling waves was examined experimentally. Results obtained by simultaneous measurements of water surface velocity by PTV and of the propagation velocity of a steep crest up to the point of breaking inception during shoaling will be reported. The experiments performed in a large wave tank examining breaking behavior of gentle spillers during shoaling on three different slopes suggest a validity of the recently proposed kinematic criterion. The breaking inception was found to occur when the horizontal velocity of the water surface on the steep (local steepness of 0.41-0.6) crest reaches a threshold value of 0.85-0.95 of that of the crest propagation. The exact moment and position of breaking inception detected using a Phase Time Method (PTM), characterizing a unique shape of the local frequency fluctuations at the inception. Future implementation of the PTM method for detection of breaking events in irregular wave fields will be discussed. Supported by German-Israeli Foundation for Scientific Research and Development (GIF) Grant #2019392.

  18. Extensions and Applications of the Bohm Criterion

    CERN Document Server

    Baalrud, Scott D; Yee, Benjamin; Hopkins, Matthew; Barnat, Edward

    2014-01-01

    The generalized Bohm criterion is revisited in the context of incorporating kinetic effects of the electron and ion distribution functions into the theory. The underlying assumptions and results of two different approaches are compared: The conventional `kinetic Bohm criterion' and a fluid-moment hierarchy approach. The former is based on the asymptotic limit of an infinitely thin sheath ($\\lambda_D/l =0$), whereas the latter is based on a perturbative expansion of a sheath that is thin compared to the plasma ($\\lambda_D/l \\ll 1$). Here $\\lambda_D$ is the Debye length, which characterizes the sheath length scale, and $l$ is a measure of the plasma or presheath length scale. The consequences of these assumptions are discussed in terms of how they restrict the class of distribution functions to which the resulting criteria can be applied. Two examples are considered to provide concrete comparisons between the two approaches. The first is a Tonks-Langmuir model including a warm ion source [Robertson 2009 \\textit...

  19. Stability and Limit Oscillations of a Control Event-Based Sampling Criterion

    Directory of Open Access Journals (Sweden)

    M. De la Sen

    2012-01-01

    Full Text Available This paper investigates the presence of limit oscillations in an adaptive sampling system. The basic sampling criterion operates in the sense that each next sampling occurs when the absolute difference of the signal amplitude with respect to its currently sampled signal equalizes a prescribed threshold amplitude. The sampling criterion is extended involving a prescribed set of amplitudes. The limit oscillations might be interpreted through the equivalence of the adaptive sampling and hold device with a nonlinear one consisting of a relay with multiple hysteresis whose parameterization is, in general, dependent on the initial conditions of the dynamic system. The performed study is performed on the time domain.

  20. Criterion for stability of a special relativistically covariant dynamical system

    Science.gov (United States)

    Horwitz, L. P.; Zucker, D.

    2017-03-01

    We study classically the problem of two relativistic particles with an invariant Duffing-like potential which reduces to the usual Duffing form in the nonrelativistic limit. We use a special relativistic generalization (RGEM) of the geometric method (GEM) developed for the analysis of nonrelativistic Hamiltonian systems to study the local stability of a relativistic Duffing oscillator. Poincaré plots of the simulated motion are consistent with the RGEM. We find a threshold for the external driving force required for chaotic behavior in the Minkowski spacetime.

  1. Discriminant Validity Assessment: Use of Fornell & Larcker criterion versus HTMT Criterion

    Science.gov (United States)

    Hamid, M. R. Ab; Sami, W.; Mohmad Sidek, M. H.

    2017-09-01

    Assessment of discriminant validity is a must in any research that involves latent variables for the prevention of multicollinearity issues. Fornell and Larcker criterion is the most widely used method for this purpose. However, a new method has emerged for establishing the discriminant validity assessment through heterotrait-monotrait (HTMT) ratio of correlations method. Therefore, this article presents the results of discriminant validity assessment using these methods. Data from previous study was used that involved 429 respondents for empirical validation of value-based excellence model in higher education institutions (HEI) in Malaysia. From the analysis, the convergent, divergent and discriminant validity were established and admissible using Fornell and Larcker criterion. However, the discriminant validity is an issue when employing the HTMT criterion. This shows that the latent variables under study faced the issue of multicollinearity and should be looked into for further details. This also implied that the HTMT criterion is a stringent measure that could detect the possible indiscriminant among the latent variables. In conclusion, the instrument which consisted of six latent variables was still lacking in terms of discriminant validity and should be explored further.

  2. PREDICTION OF YIELD FUNCTIONS ON BCC POLYCRYSTALS

    Institute of Scientific and Technical Information of China (English)

    Huang Mojia; Fu Mingfu; Zheng Chaomei

    2006-01-01

    By the nonlinear optimization theory, we predict the yield function of single BCC crystals in Hill's criterion form. Then we give a formula on the macroscopic yield function of a BCC polycrystal Ω under Sachs' model, where the volume average of the yield functions of all BCC crystallites in Ω is taken as the macroscopic yield function of the BCC polycrystal. In constructing the formula, we try to find the relationship among the macroscopic yield function, the orientation distribution function (ODF), and the single BCC crystal's plasticity. An expression for the yield stress of a uniaxial tensile problem is derived under Taylor's model in order to compare the expression with that of the macroscopic yield function.

  3. A criterion for separating process calculi

    CERN Document Server

    Banti, Federico; Tiezzi, Francesco; 10.4204/EPTCS.41.2

    2010-01-01

    We introduce a new criterion, replacement freeness, to discern the relative expressiveness of process calculi. Intuitively, a calculus is strongly replacement free if replacing, within an enclosing context, a process that cannot perform any visible action by an arbitrary process never inhibits the capability of the resulting process to perform a visible action. We prove that there exists no compositional and interaction sensitive encoding of a not strongly replacement free calculus into any strongly replacement free one. We then define a weaker version of replacement freeness, by only considering replacement of closed processes, and prove that, if we additionally require the encoding to preserve name independence, it is not even possible to encode a non replacement free calculus into a weakly replacement free one. As a consequence of our encodability results, we get that many calculi equipped with priority are not replacement free and hence are not encodable into mainstream calculi like CCS and pi-calculus, t...

  4. Nash equilibrium and multi criterion aerodynamic optimization

    Science.gov (United States)

    Tang, Zhili; Zhang, Lianhe

    2016-06-01

    Game theory and its particular Nash Equilibrium (NE) are gaining importance in solving Multi Criterion Optimization (MCO) in engineering problems over the past decade. The solution of a MCO problem can be viewed as a NE under the concept of competitive games. This paper surveyed/proposed four efficient algorithms for calculating a NE of a MCO problem. Existence and equivalence of the solution are analyzed and proved in the paper based on fixed point theorem. Specific virtual symmetric Nash game is also presented to set up an optimization strategy for single objective optimization problems. Two numerical examples are presented to verify proposed algorithms. One is mathematical functions' optimization to illustrate detailed numerical procedures of algorithms, the other is aerodynamic drag reduction of civil transport wing fuselage configuration by using virtual game. The successful application validates efficiency of algorithms in solving complex aerodynamic optimization problem.

  5. Fuzzy Clustering with Novel Separable Criterion

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Fuzzy clustering has been used widely in pattern recognition, image processing, and data analysis. An improved fuzzy clustering algorithm was developed based on the conventional fuzzy c-means (FCM) to obtain better quality clustering results. The update equations for the membership and the cluster center are derived from the alternating optimization algorithm. Two fuzzy scattering matrices in the objective function assure the compactness between data points and cluster centers, and also strengthen the separation between cluster centers in terms of a novel separable criterion. The clustering algorithm properties are shown to be an improvement over the FCM method's properties. Numerical simulations show that the clustering algorithm gives more accurate clustering results than the FCM method.

  6. Ecosystem Viable Yields

    CERN Document Server

    De Lara, Michel; Oliveros-Ramos, Ricardo; Tam, Jorge

    2011-01-01

    The World Summit on Sustainable Development (Johannesburg, 2002) encouraged the application of the ecosystem approach by 2010. However, at the same Summit, the signatory States undertook to restore and exploit their stocks at maximum sustainable yield (MSY), a concept and practice without ecosystemic dimension, since MSY is computed species by species, on the basis of a monospecific model. Acknowledging this gap, we propose a definition of "ecosystem viable yields" (EVY) as yields compatible i) with biological viability levels for all time and ii) with an ecosystem dynamics. To the difference of MSY, this notion is not based on equilibrium, but on viability theory, which offers advantages for robustness. For a generic class of multispecies models with harvesting, we provide explicit expressions for the EVY. We apply our approach to the anchovy--hake couple in the Peruvian upwelling ecosystem between the years 1971 and 1981.

  7. ICF Ignition, the Lawson Criterion, and Comparison with MFE Ignition

    Science.gov (United States)

    Betti, R.

    2009-11-01

    The Lawson criterion, which determines the onset of thermonuclear ignition, is usually expressed through the product pτ > 10 atm . s, where p is the plasma pressure in atm and τ is the energy confinement time in seconds. In magnetic fusion devices, both the pressure and confinement time are routinely measured and the performance of each discharge can be assessed by comparing the value of pτ with respect to the ignition value (10 atm . s). In inertial confinement fusion, both p and τ cannot be directly measured and the performance of surrogate and/or subignited ICF implosions cannot be assessed with respect to the ignition condition. This makes it difficult to compare the performance of ICF implosions with that of magnetic fusion energy (MFE) discharges. Here, we define the meaning of ignition in ICF implosions and compare it to MFE ignition. We then show that a multidimensional ignition condition for inertial confinement fusion can be cast in a form that depends on three measurable parameters of the compressed-fuel assembly: the hot-spot ion temperature T, the neutron yield normalized to the 1-D prediction (yield over clean or YOC) and the total areal density ρR, which includes the cold shell's contribution. A family of marginal-ignition curves are derived in the ρR--T plane.footnotetext C. D. Zhou and R. Betti, Phys. Plasmas 15, 102707 (2008). On this plane, hydrodynamic-equivalent curves show how a given implosion would perform with respect to the ignition condition when the laser-driver energy is varied. Such a criterion can be used to measure the ignition marginfootnotetext D. S. Clark, S. W. Haan, and J. D. Salmonson, Phys. Plasmas 15, 056305 (2008). of NIF targets and to predict the performance of OMEGA targets when scaled up to NIF energies. This work has been supported by the US Department of Energy under Cooperative Agreement Nos. DE-FC02-ER54789 and DE-FC52-08NA28302.

  8. Recognizing cat-eye targets with dual criterions of shape and modulation frequency

    Institute of Scientific and Technical Information of China (English)

    Ximing Ren; Li Li

    2011-01-01

    We present an image recognition method to distinguish targets with cat-eye effect from the dynamic background based on target shape and modulation frequency. Original image sequences to be processed are acquired through an imaging mechanism that utilizes a pulsed laser as active illuminator and an industrial camera as detection device. There are two criterions to recognize a target: one exploits shape priors and the other is the active illuminator's modulation frequency. The feasibility of the proposed method and its superiority over the single criterion method have been demonstrated by practical experiments.%@@ We present an image recognition method to distinguish targets with cat-eye effect from the dynamic background based on target 8hape and modulation frequency.Original image sequences to be processed are acquired through an imaging mechanism that utilizes a pulsed laser as active illuminator and an industrialcamera as detection device.There are two criterions to recognize a target: one exploits shape prior8 and the other is the active illuminator's modulation frequency.The feasibility of the proposed method and its superiority over the single criterion method have been demonstrated by practical experiments.

  9. Analytical Yield Criterion for an Anisotropic Material Containing Spherical Voids and Exhibiting Tension-Compression Asymmetry

    Science.gov (United States)

    2011-11-01

    factll rights reserved. wart ), cazacu@reef.ufl.eduthat it was deduced based on micromechanical considerations. Several modifications of Gurson’s (1977...non-zero anisotropy coefficients for three-dimensional stress conditions. Assuming triaxial loading conditions aligned with the material symmetry axes...a spherical void, subjected to plane- stress conditions, were performed for various initial porosities and different values of the anisotropy

  10. The PTSD supremacy: Criterion F in three Voyager cases.

    Science.gov (United States)

    Gaughwin, Peter

    2009-04-01

    The aim is to consider whether the courts and experts in their application of Criterion F for posttraumatic stress disorder (PTSD) have applied it consistently in civil claims brought years after the event. Three cases for compensation relating to the Voyager disaster are considered. It appears, from the cases considered in this paper, that while courts consider that Criterion F is crucial in making a diagnosis of PTSD, there are some inconsistencies in terms of understanding and applying this criterion, both by the courts and experts. This may be because of a lack of guidance in psychiatric texts as to how to apply Criterion F. Criterion F is, after the satisfaction of Criterion A(1), arguably the most important of the criteria for PTSD for, while the symptoms referred to in Criteria B-D have been shown to be fairly easy to simulate, it is arguably harder to do this with Criterion F, particularly in cases that arise a long time after the event. It is important therefore that psychiatrists assessing persons so long after an event adhere rigorously to Criterion F, because it is based on facts open to objective corroboration, while criteria B, C and D tend to rely on subjective experiences which are the most sensitive to distortion. Thus, it is to be hoped that if DSM-V is to maintain a criterion of clinically significant distress or impairment in the majority of the disorders described therein, it will provide some assistance as to how this criteria should be applied.

  11. Bayesian information criterion for censored survival models.

    Science.gov (United States)

    Volinsky, C T; Raftery, A E

    2000-03-01

    We investigate the Bayesian Information Criterion (BIC) for variable selection in models for censored survival data. Kass and Wasserman (1995, Journal of the American Statistical Association 90, 928-934) showed that BIC provides a close approximation to the Bayes factor when a unit-information prior on the parameter space is used. We propose a revision of the penalty term in BIC so that it is defined in terms of the number of uncensored events instead of the number of observations. For a simple censored data model, this revision results in a better approximation to the exact Bayes factor based on a conjugate unit-information prior. In the Cox proportional hazards regression model, we propose defining BIC in terms of the maximized partial likelihood. Using the number of deaths rather than the number of individuals in the BIC penalty term corresponds to a more realistic prior on the parameter space and is shown to improve predictive performance for assessing stroke risk in the Cardiovascular Health Study.

  12. A novel SURE-based criterion for parametric PSF estimation.

    Science.gov (United States)

    Xue, Feng; Blu, Thierry

    2015-02-01

    We propose an unbiased estimate of a filtered version of the mean squared error--the blur-SURE (Stein's unbiased risk estimate)--as a novel criterion for estimating an unknown point spread function (PSF) from the degraded image only. The PSF is obtained by minimizing this new objective functional over a family of Wiener processings. Based on this estimated blur kernel, we then perform nonblind deconvolution using our recently developed algorithm. The SURE-based framework is exemplified with a number of parametric PSF, involving a scaling factor that controls the blur size. A typical example of such parametrization is the Gaussian kernel. The experimental results demonstrate that minimizing the blur-SURE yields highly accurate estimates of the PSF parameters, which also result in a restoration quality that is very similar to the one obtained with the exact PSF, when plugged into our recent multi-Wiener SURE-LET deconvolution algorithm. The highly competitive results obtained outline the great potential of developing more powerful blind deconvolution algorithms based on SURE-like estimates.

  13. A Physics-Based Temperature Stabilization Criterion for Thermal Testing

    Science.gov (United States)

    Rickman, Steven L.; Ungar, Eugene K.

    2009-01-01

    Spacecraft testing specifications differ greatly in the criteria they specify for stability in thermal balance tests. Some specify a required temperature stabilization rate (the change in temperature per unit time, dT/dt), some specify that the final steady-state temperature be approached to within a specified difference, delta T , and some specify a combination of the two. The particular values for temperature stabilization rate and final temperature difference also vary greatly between specification documents. A one-size-fits-all temperature stabilization rate requirement does not yield consistent results for all test configurations because of differences in thermal mass and heat transfer to the environment. Applying a steady-state temperature difference requirement is problematic because the final test temperature is not accurately known a priori, especially for powered configurations. In the present work, a simplified, lumped-mass analysis has been used to explore the applicability of these criteria. A new, user-friendly, physics-based approach is developed that allows the thermal engineer to determine when an acceptable level of temperature stabilization has been achieved. The stabilization criterion can be predicted pre-test but must be refined during test to allow verification that the defined level of temperature stabilization has been achieved.

  14. Option Pricing under Risk-Minimization Criterion in an Incomplete Market with the Finite Difference Method

    Directory of Open Access Journals (Sweden)

    Xinfeng Ruan

    2013-01-01

    Full Text Available We study option pricing with risk-minimization criterion in an incomplete market where the dynamics of the risky underlying asset is governed by a jump diffusion equation with stochastic volatility. We obtain the Radon-Nikodym derivative for the minimal martingale measure and a partial integro-differential equation (PIDE of European option. The finite difference method is employed to compute the European option valuation of PIDE.

  15. Modified Schur-Cohn Criterion for Stability of Delayed Systems

    Directory of Open Access Journals (Sweden)

    Juan Ignacio Mulero-Martínez

    2015-01-01

    Full Text Available A modified Schur-Cohn criterion for time-delay linear time-invariant systems is derived. The classical Schur-Cohn criterion has two main drawbacks; namely, (i the dimension of the Schur-Cohn matrix generates some round-off errors eventually resulting in a polynomial of s with erroneous coefficients and (ii imaginary roots are very hard to detect when numerical errors creep in. In contrast to the classical Schur-Cohn criterion an alternative approach is proposed in this paper which is based on the application of triangular matrices over a polynomial ring in a similar way as in the Jury test of stability for discrete systems. The advantages of the proposed approach are that it halves the dimension of the polynomial and it only requires seeking real roots, making this modified criterion comparable to the Rekasius substitution criterion.

  16. Controllability, not chaos, key criterion for ocean state estimation

    Science.gov (United States)

    Gebbie, Geoffrey; Hsieh, Tsung-Lin

    2017-07-01

    The Lagrange multiplier method for combining observations and models (i.e., the adjoint method or 4D-VAR) has been avoided or approximated when the numerical model is highly nonlinear or chaotic. This approach has been adopted primarily due to difficulties in the initialization of low-dimensional chaotic models, where the search for optimal initial conditions by gradient-descent algorithms is hampered by multiple local minima. Although initialization is an important task for numerical weather prediction, ocean state estimation usually demands an additional task - a solution of the time-dependent surface boundary conditions that result from atmosphere-ocean interaction. Here, we apply the Lagrange multiplier method to an analogous boundary control problem, tracking the trajectory of the forced chaotic pendulum. Contrary to previous assertions, it is demonstrated that the Lagrange multiplier method can track multiple chaotic transitions through time, so long as the boundary conditions render the system controllable. Thus, the nonlinear timescale poses no limit to the time interval for successful Lagrange multiplier-based estimation. That the key criterion is controllability, not a pure measure of dynamical stability or chaos, illustrates the similarities between the Lagrange multiplier method and other state estimation methods. The results with the chaotic pendulum suggest that nonlinearity should not be a fundamental obstacle to ocean state estimation with eddy-resolving models, especially when using an improved first-guess trajectory.

  17. Controllability, not chaos, key criterion for ocean state estimation

    Directory of Open Access Journals (Sweden)

    G. Gebbie

    2017-07-01

    Full Text Available The Lagrange multiplier method for combining observations and models (i.e., the adjoint method or 4D-VAR has been avoided or approximated when the numerical model is highly nonlinear or chaotic. This approach has been adopted primarily due to difficulties in the initialization of low-dimensional chaotic models, where the search for optimal initial conditions by gradient-descent algorithms is hampered by multiple local minima. Although initialization is an important task for numerical weather prediction, ocean state estimation usually demands an additional task – a solution of the time-dependent surface boundary conditions that result from atmosphere–ocean interaction. Here, we apply the Lagrange multiplier method to an analogous boundary control problem, tracking the trajectory of the forced chaotic pendulum. Contrary to previous assertions, it is demonstrated that the Lagrange multiplier method can track multiple chaotic transitions through time, so long as the boundary conditions render the system controllable. Thus, the nonlinear timescale poses no limit to the time interval for successful Lagrange multiplier-based estimation. That the key criterion is controllability, not a pure measure of dynamical stability or chaos, illustrates the similarities between the Lagrange multiplier method and other state estimation methods. The results with the chaotic pendulum suggest that nonlinearity should not be a fundamental obstacle to ocean state estimation with eddy-resolving models, especially when using an improved first-guess trajectory.

  18. An Analytic Criterion for Turbulent Disruption of Planetary Resonances

    Science.gov (United States)

    Batygin, Konstantin; Adams, Fred C.

    2017-03-01

    Mean motion commensurabilities in multi-planet systems are an expected outcome of protoplanetary disk-driven migration, and their relative dearth in the observational data presents an important challenge to current models of planet formation and dynamical evolution. One natural mechanism that can lead to the dissolution of commensurabilities is stochastic orbital forcing, induced by turbulent density fluctuations within the nebula. While this process is qualitatively promising, the conditions under which mean motion resonances can be broken are not well understood. In this work, we derive a simple analytic criterion that elucidates the relationship among the physical parameters of the system, and find the conditions necessary to drive planets out of resonance. Subsequently, we confirm our findings with numerical integrations carried out in the perturbative regime, as well as direct N-body simulations. Our calculations suggest that turbulent resonance disruption depends most sensitively on the planet–star mass ratio. Specifically, for a disk with properties comparable to the early solar nebula with α ={10}-2, only planet pairs with cumulative mass ratios smaller than ({m}1+{m}2)/M≲ {10}-5∼ 3{M}\\oplus /{M}ȯ are susceptible to breaking resonance at semimajor axis of order a∼ 0.1 {au}. Although turbulence can sometimes compromise resonant pairs, an additional mechanism (such as suppression of resonance capture probability through disk eccentricity) is required to adequately explain the largely non-resonant orbital architectures of extrasolar planetary systems.

  19. Determination of total proteins and lactate dehydrogenase for the diagnosis of pleural transudates and exudates: redefining the classical criterion with a new statistical approach.

    Science.gov (United States)

    Maranhão, Bernardo Henrique Ferraz; Silva Junior, Cyro Teixeira da; Chibante, Antonio Monteiro da Silva; Cardoso, Gilberto Perez

    2010-01-01

    To propose a new classification criterion for the differentiation between pleural exudates and transudates-quantifying total proteins in pleural fluid (TP-PF) and lactate dehydrogenase in pleural fluid (LDH-PF) exclusively-as well as to compare this new criterion with the classical criterion in terms of diagnostic yield. This was an observational, cross-sectional study with a within-subject design, comprising 181 patients with pleural effusion treated at two university hospitals in the state of Rio de Janeiro, Brazil, between 2003 and 2006. The diagnostic parameters included in the classical criterion were identified, as were those included in the new criterion. Of the 181 patients, 152 and 29 were diagnosed with pleural exudates and pleural transudates, respectively. For the classical criterion, the sensitivity, specificity, and accuracy for the diagnosis of pleural exudates were, respectively, 99.8%, 68.6%, and 94.5%, whereas the corresponding values for the diagnosis of pleural transudates were 76.1%, 90.1%, and 87.6%. For the new criterion (cut-off points set at 3.4 g/dL for TP-PF and 328.0 U/L for LDH-PF), the sensitivity, specificity, and accuracy for the diagnosis of exudates were, respectively, 99.4%, 72.6%, and 99.2%, whereas the corresponding values for the diagnosis of transudates were 98.5%, 83.4%, and 90.0%. The accuracy of the new criterion for the diagnosis of pleural exudates was significantly greater than was that of the classical criterion (p = 0.0022). The diagnostic yield was comparable between the two criteria studied. Therefore, the new classification criterion can be used in daily practice.

  20. Failure Criterion for Brick Masonry: A Micro-Mechanics Approach

    Directory of Open Access Journals (Sweden)

    Kawa Marek

    2015-02-01

    Full Text Available The paper deals with the formulation of failure criterion for an in-plane loaded masonry. Using micro-mechanics approach the strength estimation for masonry microstructure with constituents obeying the Drucker-Prager criterion is determined numerically. The procedure invokes lower bound analysis: for assumed stress fields constructed within masonry periodic cell critical load is obtained as a solution of constrained optimization problem. The analysis is carried out for many different loading conditions at different orientations of bed joints. The performance of the approach is verified against solutions obtained for corresponding layered and block microstructures, which provides the upper and lower strength bounds for masonry microstructure, respectively. Subsequently, a phenomenological anisotropic strength criterion for masonry microstructure is proposed. The criterion has a form of conjunction of Jaeger critical plane condition and Tsai-Wu criterion. The model proposed is identified based on the fitting of numerical results obtained from the microstructural analysis. Identified criterion is then verified against results obtained for different loading orientations. It appears that strength of masonry microstructure can be satisfactorily described by the criterion proposed.

  1. Robust Hammerstein Adaptive Filtering under Maximum Correntropy Criterion

    Directory of Open Access Journals (Sweden)

    Zongze Wu

    2015-10-01

    Full Text Available The maximum correntropy criterion (MCC has recently been successfully applied to adaptive filtering. Adaptive algorithms under MCC show strong robustness against large outliers. In this work, we apply the MCC criterion to develop a robust Hammerstein adaptive filter. Compared with the traditional Hammerstein adaptive filters, which are usually derived based on the well-known mean square error (MSE criterion, the proposed algorithm can achieve better convergence performance especially in the presence of impulsive non-Gaussian (e.g., α-stable noises. Additionally, some theoretical results concerning the convergence behavior are also obtained. Simulation examples are presented to confirm the superior performance of the new algorithm.

  2. Industry Software Trustworthiness Criterion Research Based on Business Trustworthiness

    Science.gov (United States)

    Zhang, Jin; Liu, Jun-fei; Jiao, Hai-xing; Shen, Yi; Liu, Shu-yuan

    To industry software Trustworthiness problem, an idea aiming to business to construct industry software trustworthiness criterion is proposed. Based on the triangle model of "trustworthy grade definition-trustworthy evidence model-trustworthy evaluating", the idea of business trustworthiness is incarnated from different aspects of trustworthy triangle model for special industry software, power producing management system (PPMS). Business trustworthiness is the center in the constructed industry trustworthy software criterion. Fusing the international standard and industry rules, the constructed trustworthy criterion strengthens the maneuverability and reliability. Quantitive evaluating method makes the evaluating results be intuitionistic and comparable.

  3. The Bohm criterion for a dusty plasma sheath

    Indian Academy of Sciences (India)

    B P Pandey; Anjan Dutta

    2005-07-01

    The formation of the sheath in a dusty plasma is investigated. The Bohm criterion is derived for two different cases: (a) when electrons are in thermodynamic equilibrium and dust grains provide the immobile, stationary background and (b) when both electrons and ions are in thermodynamic equilibrium and dust grains are moving. In the first case, Bohm criterion gets modified due to the fluctuation of the charge on the grain surface. In the second case, the collisional and Coulombic drag play important role in determining the Bohm criterion.

  4. Energy Criterion for the Spectral Stability of Discrete Breathers

    Science.gov (United States)

    Kevrekidis, Panayotis G.; Cuevas-Maraver, Jesús; Pelinovsky, Dmitry E.

    2016-08-01

    Discrete breathers are ubiquitous structures in nonlinear anharmonic models ranging from the prototypical example of the Fermi-Pasta-Ulam model to Klein-Gordon nonlinear lattices, among many others. We propose a general criterion for the emergence of instabilities of discrete breathers analogous to the well-established Vakhitov-Kolokolov criterion for solitary waves. The criterion involves the change of monotonicity of the discrete breather's energy as a function of the breather frequency. Our analysis suggests and numerical results corroborate that breathers with increasing (decreasing) energy-frequency dependence are generically unstable in soft (hard) nonlinear potentials.

  5. Investigation of PMU performance under TVE criterion

    DEFF Research Database (Denmark)

    Yang, GuangYa; Martin, K. E.; Østergaard, Jacob

    2010-01-01

    . To evaluate the measurement quality, the concepts of total vector error (TVE) and benchmark tests, including the magnitude, phase and frequency step tests, are proposed in the C37.118 standard. It also includes requirements for test results. This paper reports the results of tests performed on several PMUs....... These tests include both steady state and dynamic conditions conforming to the new requirements under development by the IEEE for the updated C37.118 standard. In addition to validating the new IEEE requirements with actual PMU measurements, the results evaluated by TVE are discussed and with errors analyzed...

  6. Corrections to the Eckhaus' stability criterion for one-dimensional stationary structures

    Science.gov (United States)

    Malomed, B. A.; Staroselsky, I. E.; Konstantinov, A. B.

    1989-01-01

    Two amendments to the well-known Eckhaus' stability criterion for small-amplitude non-linear structures generated by weak instability of a spatially uniform state of a non-equilibrium one-dimensional system against small perturbations with finite wavelengths are obtained. Firstly, we evaluate small corrections to the main Eckhaus' term which, on the contrary so that term, do not have a universal form. Comparison of those non-universal corrections with experimental or numerical results gives a possibility to select a more relevant form of an effective nonlinear evolution equation. In particular, the comparison with such results for convective rolls and Taylor vortices gives arguments in favor of the Swift-Hohenberg equation. Secondly, we derive an analog of the Eckhaus criterion for systems degenerate in the sense that in an expansion of their non-linear parts in powers of dynamical variables, the second and third degree terms are absent.

  7. A General Criterion for Liquefaction in Granular Layers with Heterogeneous Pore Pressure

    CERN Document Server

    Goren, Liran; Aharonov, Einat; Sparks, David; Flekkøy, Eirik Grude

    2013-01-01

    Fluid-saturated granular and porous layers can undergo liquefaction and lose their shear resistance when subjected to shear forcing. In geosystems, such a process can lead to severe natural hazards of soil liquefaction, accelerating slope failure, and large earthquakes. Terzaghi's principle of effective stress predicts that liquefaction occurs when the pore pressure within the layer becomes equal to the applied normal stress on the layer. However, under dynamic loading and when the internal permeability is relatively small the pore pressure is spatially heterogeneous and it is not clear what measurement of pore pressure should be used in Terzaghi's principle. Here, we show theoretically and demonstrate using numerical simulations a general criterion for liquefaction that applies also for the cases in which the pore pressure is spatially heterogeneous. The general criterion demands that the average pore pressure along a continuous surface within the fluid-saturated granular or porous layer is equal to the appl...

  8. A multiloop generalization of the circle criterion for stability margin analysis

    Science.gov (United States)

    Safonov, M. G.; Athans, M.

    1981-01-01

    In order to provide a theoretical tool well suited for use in characterizing the stability margins (e.g., gain and phase margins) of multiloop feedback systems, multiloop input-output stability results generalizing the circle stability criterion are considered. Generalized conic sectors with 'centers' and 'radii' determined by linear dynamical operators are employed to enable an engineer to specify the stability margins which he desires as a frequency-dependent convex set of modeling errors (including nonlinearities, gain variations, and phase variations) which the system must be able to tolerate in each feedback loop without instability. The resulting stability criterion gives sufficient conditions for closed-loop stability in the presence of such frequency-dependent modeling errors, even when the modeling errors occur simultaneously in all loops.

  9. MARSHALLIAN DEVIATION:NEW OBSERVABLE CRITERION TO MEASURE TRANSACTION PATHS IN DOUBLE AUCTION MARKETS

    Institute of Scientific and Technical Information of China (English)

    ZHANWenjie; WANGShouyang; 等

    2002-01-01

    In measuring the trade process in a double anction(DA) market,there is not any observable criterion that is able to describe the matching pairs and their transaction order dynamically,In this paper,we propse a new observable criterion called Marshallian deviation.It can be used to measure the distance of a transaction path deviating from the Marshallian path mathematically,and to answer the question why buyers with high values will trade with sellers with low costs in advance in some types of DA but not in others.Furthermore,three factors influencing the Marshallian deviations both in the CDA and in the PDA are also studied.They are repectively the strategic algorithm,the transaction duration and the number of traders.A few intersting findings are presented.

  10. MARSHALLIAN DEVIATION: NEW OBSERVABLE CRITERION TO MEASURE TRANSACTION PATHS IN DOUBLE AUCTION MARKETS

    Institute of Scientific and Technical Information of China (English)

    ZHAN Wenjie; WANG Shouyang; ZHANG Jinlong; YANG Jie; K.K. Lai

    2002-01-01

    In measuring the trade process in a double auction (DA) market, there is not any observable criterion that is able to describe the matching pairs and their transaction order dynamically. In this paper, we propose a new observable criterion called Marshalliandeviation. It can be used to measure the distance of a transaction path deviating from theMarshallian path mathematically, and to answer the question why buyers with high valueswill trade with sellers with low costs in advance in some types of DA but not in others.Furthermore, three factors influencing the Marshallian deviations both in the CDA and inthe PDA are also studied. They are respectively the strategic algorithm, the transactionduration and the number of traders. A few interesting findings are presented.

  11. Bayesian Information Criterion as an Alternative way of Statistical Inference

    Directory of Open Access Journals (Sweden)

    Nadejda Yu. Gubanova

    2012-05-01

    Full Text Available The article treats Bayesian information criterion as an alternative to traditional methods of statistical inference, based on NHST. The comparison of ANOVA and BIC results for psychological experiment is discussed.

  12. Norm Referenced and Criterion Based Measures with Preschoolers

    Science.gov (United States)

    MacTurk, Robert H.; Neisworth, John T.

    1978-01-01

    Seventeen handicapped and nonhandicapped preschool children were given both the norm referenced Gesell Developmental Schedules and the criterion based HICOMP progress measure on a quarterly (10 week) basis. (Author/SBH)

  13. A modified failure criterion for transversely isotropic rocks

    Institute of Scientific and Technical Information of China (English)

    Omid Saeidi; Vamegh Rasouli; Rashid Geranmayeh Vaneghi; Raoof Gholami; Seyed Rahman Torabi

    2014-01-01

    A modified failure criterion is proposed to determine the strength of transversely isotropic rocks. Me-chanical properties of some metamorphic and sedimentary rocks including gneiss, slate, marble, schist, shale, sandstone and limestone, which show transversely isotropic behavior, were taken into consider-ation. Afterward, introduced triaxial rock strength criterion was modified for transversely isotropic rocks. Through modification process an index was obtained that can be considered as a strength reduction parameter due to rock strength anisotropy. Comparison of the parameter with previous anisotropy in-dexes in literature showed reasonable results for the studied rock samples. The modified criterion was compared to modified Hoek-Brown and Ramamurthy criteria for different transversely isotropic rocks. It can be concluded that the modified failure criterion proposed in this study can be used for predicting the strength of transversely isotropic rocks.

  14. On the Matrix Formulation of Kaiser's Varimax Criterion.

    Science.gov (United States)

    Neudecker, H.

    1981-01-01

    A full-fledged matrix derivation of Sherin's matrix formulation of Kaiser's varimax criterion is provided. Matrix differential calculus is used in conjunction with the Hadamard (or Schur) matrix product. Two results on Hadamard products are presented. (Author/JKS)

  15. Bayesian Information Criterion as an Alternative way of Statistical Inference

    OpenAIRE

    Nadejda Yu. Gubanova; Simon Zh. Simavoryan

    2012-01-01

    The article treats Bayesian information criterion as an alternative to traditional methods of statistical inference, based on NHST. The comparison of ANOVA and BIC results for psychological experiment is discussed.

  16. Self-Adjointness Criterion for Operators in Fock Spaces

    Energy Technology Data Exchange (ETDEWEB)

    Falconi, Marco, E-mail: marco.falconi@univ-rennes1.fr [Université de Rennes I, IRMAR and Centre Henri Lebesgue (France)

    2015-12-15

    In this paper we provide a criterion of essential self-adjointness for operators in the tensor product of a separable Hilbert space and a Fock space. The class of operators we consider may contain a self-adjoint part, a part that preserves the number of Fock space particles and a non-diagonal part that is at most quadratic with respect to the creation and annihilation operators. The hypotheses of the criterion are satisfied in several interesting applications.

  17. Trace Ratio Criterion for Feature Extraction in Classification

    Directory of Open Access Journals (Sweden)

    Guoqi Li

    2014-01-01

    Full Text Available A generalized linear discriminant analysis based on trace ratio criterion algorithm (GLDA-TRA is derived to extract features for classification. With the proposed GLDA-TRA, a set of orthogonal features can be extracted in succession. Each newly extracted feature is the optimal feature that maximizes the trace ratio criterion function in the subspace orthogonal to the space spanned by the previous extracted features.

  18. On the Smoothed Minimum Error Entropy Criterion 

    Directory of Open Access Journals (Sweden)

    Badong Chen

    2012-11-01

    Full Text Available Recent studies suggest that the minimum error entropy (MEE criterion can outperform the traditional mean square error criterion in supervised machine learning, especially in nonlinear and non-Gaussian situations. In practice, however, one has to estimate the error entropy from the samples since in general the analytical evaluation of error entropy is not possible. By the Parzen windowing approach, the estimated error entropy converges asymptotically to the entropy of the error plus an independent random variable whose probability density function (PDF corresponds to the kernel function in the Parzen method. This quantity of entropy is called the smoothed error entropy, and the corresponding optimality criterion is named the smoothed MEE (SMEE criterion. In this paper, we study theoretically the SMEE criterion in supervised machine learning where the learning machine is assumed to be nonparametric and universal. Some basic properties are presented. In particular, we show that when the smoothing factor is very small, the smoothed error entropy equals approximately the true error entropy plus a scaled version of the Fisher information of error. We also investigate how the smoothing factor affects the optimal solution. In some special situations, the optimal solution under the SMEE criterion does not change with increasing smoothing factor. In general cases, when the smoothing factor tends to infinity, minimizing the smoothed error entropy will be approximately equivalent to minimizing error variance, regardless of the conditional PDF and the kernel.

  19. New Quality Assessment Criterion of AlSi5Cu1 Alloy

    Directory of Open Access Journals (Sweden)

    M. Wierzbińska

    2007-07-01

    Full Text Available The paper presents the discussion of the results of mechanical testing for aluminium foundry alloy AlSi5Cu1Mg for high-loaded machine elements. Values of yield strength (Rp0.2, tensile strength (Rm, elongation(A5 and hardness (HB are usually considered as the primary quality assessment criterion for a manufacturing process. It was concluded, that this criterion, A5 index particularly, is unsatisfactory to estimate the plasticity of the alloy and its crack resistance in the presence of sharp-pointed stress concentrators or microcracks. More adequate parameter is plane strain fracture toughness KIc. However, size of the samples appeared to be twice as large as would be needed to fulfill requirements of test conditions, and the test itself is laborious and time-consuming that it becomes impractical as a acceptance test. Therefore, substitute test for quality assessment – determination of tensile strength in the presence of a sharp notch kmR was applied. The comparative analysis of kmR/Rp0.2 ratio, as a more enhanced fatigue resistance criterion than kmR and plane strain fracture toughness KIc of the alloy was performed. It was assumed that kmR/Rp0.2 parameter has good correlation with the critical stress intensity factor KIc Thus, under manufacturing process conditions, being unable to carry out KIc test, it may be successfully replaced by kmR test.

  20. Incorporating phenology into yield models

    Science.gov (United States)

    Gray, J. M.; Friedl, M. A.

    2015-12-01

    Because the yields of many crops are sensitive to meteorological forcing during specific growth stages, phenological information has potential utility in yield mapping and forecasting exercises. However, most attempts to explain the spatiotemporal variability in crop yields with weather data have relied on growth stage definitions that do not change from year-to-year, even though planting, maturity, and harvesting dates show significant interannual variability. We tested the hypothesis that quantifying temperature exposures over dynamically determined growth stages would better explain observed spatiotemporal variability in crop yields than statically defined time periods. Specifically, we used National Agricultural and Statistics Service (NASS) crop progress data to identify the timing of the start of the maize reproductive growth stage ("silking"), and examined the correlation between county-scale yield anomalies and temperature exposures during either the annual or long-term average silking period. Consistent with our hypothesis and physical understanding, yield anomalies were more correlated with temperature exposures during the actual, rather than the long-term average, silking period. Nevertheless, temperature exposures alone explained a relatively low proportion of the yield variability, indicating that other factors and/or time periods are also important. We next investigated the potential of using remotely sensed land surface phenology instead of NASS progress data to retrieve crop growth stages, but encountered challenges related to crop type mapping and subpixel crop heterogeneity. Here, we discuss the potential of overcoming these challenges and the general utility of remotely sensed land surface phenology in crop yield mapping.

  1. Market Orientation within University Schools of Business: Can a Dynamical Systems Viewpoint Applied to a Non-Temporal Data Set Yield Valuable Insights for University Managers?

    Science.gov (United States)

    Cox, John C.; Webster, Robert L.; Hammond, Kevin L.

    2009-01-01

    This study investigates the use of using complexity theory--the study of nonlinear dynamical systems of which chaos and catastrophe theory are subsets--in the analysis of a non temporal data set to derive valuable insights into the functioning of university schools of business. The approach is unusual in that studies of nonlinearity in complex…

  2. Application of an InGaAsP diode laser to probe photodissociation dynamics - I(asterisk) quantum yields from n- and i-C3F7I and CH3I by laser gain vs absorption spectroscopy

    Science.gov (United States)

    Hess, W. P.; Kohler, S. J.; Haugen, H. K.; Leone, S. R.

    1986-01-01

    Initial measurements on I-asterisk yields of alkyl iodides at 266 nm are reported using gain vs. absorption spectroscopy with an InGaAsP diode probe laser. The results are 102 percent + or - 4 percent, 102 percent + or - 7 percent, and 73 percent + or - 4 percent for n-C3F7I, i-C3F7I, and CH3I respectively. Future prospects for the development of diode laser systems and for their use in dynamical studies are discussed.

  3. Elastic-Plastic Strain Acceptance Criteria for Structures Subject to Rapidly Applied Transient Dynamic Loading

    Energy Technology Data Exchange (ETDEWEB)

    W.R. Solonick

    2003-04-01

    Rapidly applied transient dynamic loads produce stresses and deflections in structures that typically exceed those from static loading conditions. Previous acceptance criteria for structures designed for rapidly applied transient dynamic loading limited stresses to those determined from elastic analysis. Different stress limits were established for different grades of structure depending upon the amount of permanent set considered acceptable. Structure allowed to sustain very limited permanent set is designed to stress limits not significantly greater than yield stress. Greater permanent set in structure under rapidly applied transient dynamic loading conditions is permitted by establishing stress limits that are significantly greater than yield stress but still provide adequate safety margin (with respect to failure). This paper presents a strain-based elastic-plastic (i.e., inelastic) analysis criterion developed as an alternative to the more conservative stress-based elastic analysis stress criterion for structures subjected to rapidly applied transient dynamic loading. The strain limits established are based on material ductility considerations only and are set as a fraction of the strain at ultimate stress obtained from an engineering stress/strain curve of the material. Strains limits are categorized by type as membrane or surface and by region as general, local , or concentrated. The application of the elastic-plastic criterion provides a more accurate, less conservative design/analysis basis for structures than that used in elastic stress-based analysis criteria, while still providing adequate safety margins.

  4. Energy conditions and DK stability criterion in the non-local gravity

    CERN Document Server

    Wu, Ya-Bo; Yang, Wei-Qiang; Zhang, Nan; Chen, Bo-Hai

    2016-01-01

    We study and derive the energy conditions and the Dolgov-Kawasaki (DK) stability criterion in non-local gravity, which is the modified theory of general relativity (GR) obtained by adding a term $m^2R\\Box^{-2}R$ to the Einstein-Hilbert action. Moreover, in order to get some insight on the meaning of the energy conditions, we illustrate the evolutions of four energy conditions with the parameter $\\alpha$ and redshift $z$. By analysis we give the constraint on the parameters $\\alpha$, namely, $|\\alpha|\\leq0.26$. Furthermore, by means of the Dolgov-Kawasaki stability criterion in the non-local gravity we find that the effective mass $m_\\text{eff}^2$ of the dynamical field $U$ is negative in any value ranges of parameter $\\alpha$, which is consistent with the result given in [JCAP 1607, 003 (2016)], i.e. the field $U$ is a ghost one. The result shows that the Dolgov-Kawasaki stability criterion cannot give any constraint on the parameter $\\alpha$.

  5. Scale-up criterion of power consumption for a surface aerator used in wastewater treatment tank

    Directory of Open Access Journals (Sweden)

    Hayder M. Issa

    2016-01-01

    Full Text Available The major part of operation costs in surface aeration basins or tanks is because of power requirements. Therefore, it is always necessary to find a dependable criterion for the predictive scale-up of power consumption measurements obtained at laboratory-scale surface aeration tanks to industrial-scale wastewater treatment surface aeration systems. A scale-up approach was proposed in this work for volumetric power consumption between geometrically similar laboratory-scale and industrial full-scale surface aeration tanks at an invariant Froude number Fr. Scale-up order between the laboratory and industrial sizes was 7.4. A mathematical correlation has been developed to estimate the volumetric power consumption and then compared with a model that already was investigated experimentally. Scale-up criterion involved the evaluation of three similarities; the geometrical, kinematic and dynamics. The scale-up basis that developed in this work led us to achieve a suitable scale-up criterion for volumetric power consumption in aeration tanks at matched surface flow condition. At matched Froude number Fr for the laboratory and industrial scales and at low and moderate turbine rotation speeds for surface aeration than 0.8 rps, complete predictions of volumetric power consumption have been achieved. The prediction by the existing previous model showed higher results than the actual values.

  6. Lattice instability during phase transformations under multiaxial stress: Modified transformation work criterion

    Science.gov (United States)

    Levitas, Valery I.; Chen, Hao; Xiong, Liming

    2017-08-01

    A continuum/atomistic approach for predicting lattice instability during crystal-crystal phase transformations (PTs) is developed for the general loading with an arbitrary stress tensor and large strains. It is based on a synergistic combination of the generalized Landau-type theory for PTs and molecular dynamics (MD) simulations. The continuum approach describes the entire dissipative transformation process in terms of an order parameter, and the general form of the instability criterion is derived utilizing the second law of thermodynamics. The feedback from MD allowed us to present the instability criterion for both direct and reverse PTs in terms of the critical value of the modified transformation work, which is linear in components of the true stress tensor. It was calibrated by MD simulations for direct and reverse PTs between semiconducting silicon Si i and metallic Si ii phases under just two different stress states. Then, it describes hundreds of MD simulations under various combinations of three normal and three shear stresses. In particular, the atomistic simulations show that the effects of all three shear stresses along cubic axes on lattice instability of Si i are negligible, which is in agreement with our criterion.

  7. Formulation of cross-anisotropic failure criterion for soils

    Directory of Open Access Journals (Sweden)

    Yi-fei SUN

    2013-10-01

    Full Text Available Inherently anisotropic soil fabric has a considerable influence on soil strength. To model this kind of inherent anisotropy, a three-dimensional anisotropic failure criterion was proposed, employing a scalar-valued anisotropic variable and a modified general three- dimensional isotropic failure criterion. The scalar-valued anisotropic variable in all sectors of the deviatoric plane was defined by correlating a normalized stress tensor with a normalized fabric tensor. Detailed comparison between the available experimental data and the corresponding model predictions in the deviatoric plane was conducted. The proposed failure criterion was shown to well predict the failure behavior in all sectors, especially in sector II with the Lode angle ranging between 60º and 120º, where the prediction was almost in accordance with test data. However, it was also observed that the proposed criterion overestimated the strength of dense Santa Monica Beach sand in sector III where the intermediate principal stress ratio b varied from approximately 0.2 to 0.8, and slightly underestimated the strength when b was between approximately 0.8 and 1. The difference between the model predictions and experimental data was due to the occurrence of shear bending, which might reduce the measured strength. Therefore, the proposed anisotropic failure criterion has a strong ability to characterize the failure behavior of various soils and potentially allows a better description of the influence of the loading direction with respect to the soil fabric.

  8. Low-Yield Cigarettes

    Science.gov (United States)

    ... Program Division of Reproductive Health More CDC Sites Low-Yield Cigarettes Recommend on Facebook Tweet Share Compartir ... they compensate when smoking them. Smokers Who Use Low-Yield Cigarettes Many smokers consider smoking low-yield ...

  9. Distribution of forces between synergistics and antagonistics muscles using an optimization criterion depending on muscle contraction behavior.

    Science.gov (United States)

    Rengifo, Carlos; Aoustin, Yannick; Plestan, Franck; Chevallereau, Christine

    2010-04-01

    In this paper, a new neuromusculoskeletal simulation strategy is proposed. It is based on a cascade control approach with an inner muscular-force control loop and an outer joint-position control loop. The originality of the work is located in the optimization criterion used to distribute forces between synergistic and antagonistic muscles. The cost function and the inequality constraints depend on an estimation of the muscle fiber length and its time derivative. The advantages of a such criterion are exposed by theoretical analysis and numerical tests. The simulation model used in the numerical tests consists in an anthropomorphic arm model composed by two joints and six muscles. Each muscle is modeled as a second-order dynamical system including activation and contraction dynamics. Contraction dynamics is represented using a classical Hill's model.

  10. 考虑供给风险及销售努力的动态定价问题研究%Dynamic pricing with yield risks and sale effort

    Institute of Scientific and Technical Information of China (English)

    庆艳华; 左小德

    2015-01-01

    Supply chain are facing challenge due to the complexity and uncertainty of competitive environment. Based on newsboy model, this paper investigates the dynamic pricing with yield risks and sale effort which can influence demand. Through analysis and comparison of dynamic pricing, dynamic pricing with sale effort and fixed pricing and numerical experiments, the results show that when the product is less flexible and the actual supply is small, dynamic pricing can effectively eliminates the loss of yield risk. And it’s useful to increase sale effort when the actual supply is bigger.%针对企业或供应链面临的供给风险,以报童问题为基础,研究了动态定价的问题,并进一步考虑需求同时受到价格和销售努力影响时的动态定价策略。对考虑销售努力的动态定价,动态定价及固定定价三种策略进行比较分析,并通过数值实验验证当产品弹性较小,实际供给量较小时动态定价能够有效降低供给风险所带来的影响,而当实际供给量较大时,销售努力的作用才更加明显。

  11. Experiments and modeling of ballistic penetration using an energy failure criterion

    Directory of Open Access Journals (Sweden)

    Dolinski M.

    2015-01-01

    Full Text Available One of the most intricate problems in terminal ballistics is the physics underlying penetration and perforation. Several penetration modes are well identified, such as petalling, plugging, spall failure and fragmentation (Sedgwick, 1968. In most cases, the final target failure will combine those modes. Some of the failure modes can be due to brittle material behavior, but penetration of ductile targets by blunt projectiles, involving plugging in particular, is caused by excessive localized plasticity, with emphasis on adiabatic shear banding (ASB. Among the theories regarding the onset of ASB, new evidence was recently brought by Rittel et al. (2006, according to whom shear bands initiate as a result of dynamic recrystallization (DRX, a local softening mechanism driven by the stored energy of cold work. As such, ASB formation results from microstructural transformations, rather than from thermal softening. In our previous work (Dolinski et al., 2010, a failure criterion based on plastic strain energy density was presented and applied to model four different classical examples of dynamic failure involving ASB formation. According to this criterion, a material point starts to fail when the total plastic strain energy density reaches a critical value. Thereafter, the strength of the element decreases gradually to zero to mimic the actual material mechanical behavior. The goal of this paper is to present a new combined experimental-numerical study of ballistic penetration and perforation, using the above-mentioned failure criterion. Careful experiments are carried out using a single combination of AISI 4340 FSP projectiles and 25[mm] thick RHA steel plates, while the impact velocity, and hence the imparted damage, are systematically varied. We show that our failure model, which includes only one adjustable parameter in this present work, can faithfully reproduce each of the experiments without any further adjustment. Moreover, it is shown that the

  12. Bipartite quantum systems: on the realignment criterion and beyond

    Energy Technology Data Exchange (ETDEWEB)

    Lupo, Cosmo; Aniello, Paolo [Dipartimento di Scienze Fisiche dell' Universita di Napoli ' Federico II' , via Cintia, I-80126 Napoli (Italy); Scardicchio, Antonello [Princeton Center for Theoretical Physics and Department of Physics, Princeton University, Princeton, NJ 08544 (United States)], E-mail: lupo@na.infn.it, E-mail: aniello@na.infn.it, E-mail: ascardic@princeton.edu

    2008-10-17

    Inspired by the 'computable cross norm' or 'realignment' criterion, we propose a new point of view about the characterization of the states of bipartite quantum systems. We consider a Schmidt decomposition of a bipartite density operator. The corresponding Schmidt coefficients, or the associated symmetric polynomials, are regarded as quantities that can be used to characterize bipartite quantum states. In particular, starting from the realignment criterion, a family of necessary conditions for the separability of bipartite quantum states are derived. We conjecture that these conditions, which are weaker than the parent criterion, can be strengthened in such a way to obtain a new family of criteria that are independent of the original one. This conjecture is supported by numerical examples for the low dimensional cases. These ideas can be applied to the study of quantum channels, leading to a relation between the rate of contraction of a map and its ability to preserve entanglement.

  13. A Joint Optimization Criterion for Blind DS-CDMA Detection

    Directory of Open Access Journals (Sweden)

    Sergio A. Cruces-Alvarez

    2007-01-01

    Full Text Available This paper addresses the problem of the blind detection of a desired user in an asynchronous DS-CDMA communications system with multipath propagation channels. Starting from the inverse filter criterion introduced by Tugnait and Li in 2001, we propose to tackle the problem in the context of the blind signal extraction methods for ICA. In order to improve the performance of the detector, we present a criterion based on the joint optimization of several higher-order statistics of the outputs. An algorithm that optimizes the proposed criterion is described, and its improved performance and robustness with respect to the near-far problem are corroborated through simulations. Additionally, a simulation using measurements on a real software-radio platform at 5 GHz has also been performed.

  14. ABSOLUTE STABILIZATION RELATED TO CIRCLE CRITERION: AN LMI-BASED APPROACH

    Institute of Scientific and Technical Information of China (English)

    杨莹; 黄琳

    2003-01-01

    A method is proposed for synthesizing output feedback controllers for nonlinear Lur' e systems. The problem of designing an output dynamic controller for uncertain-free systems and systems subject to multiplicative norm-bounded perturbations in the linear part were proposed respectively. The procedure is based on the use of the absolute stability,through the circle criterion, and a linear matrix inequalities (LMI) formulation. The controller existence conditions are given in terms of existence of suitable solutions to a set of parameter- dependent LMIs.

  15. Searchless tuning of linear controllers for the minimum of quadratic criterion

    Science.gov (United States)

    Pikina, G. A.; Burtseva, Yu. S.

    2014-03-01

    A searchless method of calculating the tunings of typical controllers is developed for linear plants with a time delay, the use of which makes it possible to minimize the quadratic criterion I 2 with respect to an internal disturbance. The basic idea of the method consists in obtaining the complex frequency response of a suboptimal linear controller, followed by approaching the characteristic of a typical controller to this frequency response in the essential frequency band using the least squares method. Recommendations on selecting the smoothing filter time constant and the suboptimal system's dynamic error are given for a system comprising a PID controller and a second-order plant with a time delay.

  16. Statistical comparison of dynamic contrast-enhanced MRI pharmacokinetic models in human breast cancer.

    Science.gov (United States)

    Li, Xia; Welch, E Brian; Chakravarthy, A Bapsi; Xu, Lei; Arlinghaus, Lori R; Farley, Jaime; Mayer, Ingrid A; Kelley, Mark C; Meszoely, Ingrid M; Means-Powell, Julie; Abramson, Vandana G; Grau, Ana M; Gore, John C; Yankeelov, Thomas E

    2012-07-01

    By fitting dynamic contrast-enhanced MRI data to an appropriate pharmacokinetic model, quantitative physiological parameters can be estimated. In this study, we compare four different models by applying four statistical measures to assess their ability to describe dynamic contrast-enhanced MRI data obtained in 28 human breast cancer patient sets: the chi-square test (χ(2)), Durbin-Watson statistic, Akaike information criterion, and Bayesian information criterion. The pharmacokinetic models include the fast exchange limit model with (FXL_v(p)) and without (FXL) a plasma component, and the fast and slow exchange regime models (FXR and SXR, respectively). The results show that the FXL_v(p) and FXR models yielded the smallest χ(2) in 45.64 and 47.53% of the voxels, respectively; they also had the smallest number of voxels showing serial correlation with 0.71 and 2.33%, respectively. The Akaike information criterion indicated that the FXL_v(p) and FXR models were preferred in 42.84 and 46.59% of the voxels, respectively. The Bayesian information criterion also indicated the FXL_v(p) and FXR models were preferred in 39.39 and 45.25% of the voxels, respectively. Thus, these four metrics indicate that the FXL_v(p) and the FXR models provide the most complete statistical description of dynamic contrast-enhanced MRI time courses for the patients selected in this study.

  17. Li's criterion for the Riemann hypothesis - numerical approach

    Directory of Open Access Journals (Sweden)

    Krzysztof Maślanka

    2004-01-01

    Full Text Available There has been some interest in a criterion for the Riemann hypothesis proved recently by Xian-Jin Li [Li X.-J.: The Positivity of a Sequence of Numbers and the Riemann Hypothesis. J. Number Theory 65 (1997, 325-333]. The present paper reports on a numerical computation of the first 3300 of Li's coefficients which appear in this criterion. The main empirical observation is that these coefficients can be separated in two parts. One of these grows smoothly while the other is very small and oscillatory. This apparent smallness is quite unexpected. If it persisted till infinity then the Riemann hypothesis would be true.

  18. A New Criterion for Disruption Prediction on HL-2A

    Institute of Scientific and Technical Information of China (English)

    YANG Qing-Wei; JI Xiao-Quan; DING Xuan-Tong; HL-2A team; ZHOU Hang-Yu; FENG Bei-Bin; LIU Yi; PAN Yu-Dong; LI Wei; DUAN Xu-Ru; CHEN Wei; CUI Zheng-Ying

    2006-01-01

    @@ A new criterion has been proposed to predict the major disruptions caused by tearing mode instabilities. According to the HL-2A experimental results, the statistical analyses are employed to investigate the relationships between MHD activities and the plasma disruptions. Two kinds of the tearing mode activities can finally cause the disruption on HL-2A operations. By introducing a new parameter, i.e. an integral of poloidal magnetic field over time, as the criterion of disruption precursor, almost all of the disruptions can be predicted.

  19. Automatic control systems satisfying certain general criterions on transient behavior

    Science.gov (United States)

    Boksenbom, Aaron S; Hood, Richard

    1952-01-01

    An analytic method for the design of automatic controls is developed that starts from certain arbitrary criterions on the behavior of the controlled system and gives those physically realizable equations that the control system can follow in order to realize this behavior. The criterions used are developed in the form of certain time integrals. General results are shown for systems of second order and of any number of degrees of freedom. Detailed examples for several cases in the control of a turbojet engine are presented.

  20. A derivability criterion based on the existence of adjunctions

    CERN Document Server

    Rodriguez-Gonzalez, Beatriz

    2012-01-01

    In this paper we introduce a derivability criterion of functors based on the existence of adjunctions rather than on the existence of resolutions. It constitutes a converse of Quillen-Maltsiniotis derived adjunction theorem. We present two applications of our derivability criterion. On the one hand, we prove that the two notions for homotopy colimits corresponding to Grothendieck derivators and Quillen model categories are equivalent. On the other hand, we deduce that the internal hom for derived Morita theory constructed by B. To\\"en is indeed the right derived functor of the internal hom of dg-categories.

  1. Many-particle entanglement criterion for superradiant-like states

    CERN Document Server

    Tasgin, Mehmet Emre

    2016-01-01

    We derive a many-particle inseparability criterion for mixed states using the relation between single-mode and many-particle nonclassicalities. It works very well not only in the vicinity of the Dicke states, but also for the superposition of them: superradiant ground state of finite/infinite number of particles and time evolution of single-photon superradiance. We also obtain a criterion for ensemble-field entanglement which works fine for such kind of states. Even though the collective excitations of the many-particle system is sub-Poissonian --which results in entanglement-- the wave function displays bunching.

  2. OIL MONITORING DIAGNOSTIC CRITERIONS BASED ON MAXIMUM ENTROPY PRINCIPLE

    Institute of Scientific and Technical Information of China (English)

    Huo Hua; Li Zhuguo; Xia Yanchun

    2005-01-01

    A method of applying maximum entropy probability density estimation approach to constituting diagnostic criterions of oil monitoring data is presented. The method promotes the precision of diagnostic criterions for evaluating the wear state of mechanical facilities, and judging abnormal data. According to the critical boundary points defined, a new measure on monitoring wear state and identifying probable wear faults can be got. The method can be applied to spectrometric analysis and direct reading ferrographic analysis. On the basis of the analysis and discussion of two examples of 8NVD48A-2U diesel engines, the practicality is proved to be an effective method in oil monitoring.

  3. Dynamics of cover, UV-protective pigments, and quantum yield in biological soil crust communities of an undisturbed Mojave Desert shrubland

    Science.gov (United States)

    Belnap, J.; Phillips, S.L.; Smith, S.D.

    2007-01-01

    Biological soil crusts are an integral part of dryland ecosystems. We monitored the cover of lichens and mosses, cyanobacterial biomass, concentrations of UV-protective pigments in both free-living and lichenized cyanobacteria, and quantum yield in the soil lichen species Collema in an undisturbed Mojave Desert shrubland. During our sampling time, the site received historically high and low levels of precipitation, whereas temperatures were close to normal. Lichen cover, dominated by Collema tenax and C. coccophorum, and moss cover, dominated by Syntrichia caninervis, responded to both increases and decreases in precipitation. This finding for Collema spp. at a hot Mojave Desert site is in contrast to a similar study conducted at a cool desert site on the Colorado Plateau in SE Utah, USA, where Collema spp. cover dropped in response to elevated temperatures, but did not respond to changes in rainfall. The concentrations of UV-protective pigments in free-living cyanobacteria at the Mojave Desert site were also strongly and positively related to rainfall received between sampling times (R2 values ranged from 0.78 to 0.99). However, pigment levels in the lichenized cyanobacteria showed little correlation with rainfall. Quantum yield in Collema spp. was closely correlated with rainfall. Climate models in this region predict a 3.5-4.0 ??C rise in temperature and a 15-20% decline in winter precipitation by 2099. Based on our data, this rise in temperature is unlikely to have a strong effect on the dominant species of the soil crusts. However, the predicted drop in precipitation will likely lead to a decrease in soil lichen and moss cover, and high stress or mortality in soil cyanobacteria as levels of UV-protective pigments decline. In addition, surface-disturbing activities (e.g., recreation, military activities, fire) are rapidly increasing in the Mojave Desert, and these disturbances quickly remove soil lichens and mosses. These stresses combined are likely to lead to

  4. Study on dynamic anti-sliding stability of a high gravity dam considering complex dam foundation

    Directory of Open Access Journals (Sweden)

    Deng-hong CHEN

    2011-06-01

    Full Text Available There existed some limitations when analyzing the anti-sliding seismic stability of dam-foundation system by traditional pseudo-static method and response spectrum method. The dynamic strength reduction method was used to study on the deep anti-sliding stability of a high gravity dam considering complex dam foundation under strong earthquake-induced ground action. The static analysis was firstly carried out by reducing the shear strength parameters of the dam foundation’s rock mass with equal proportion. Then, the time-history seismic analysis was carried out based on the static analysis. It was proposed as one of dynamic instability criterions that the peak values of the dynamic displacements and plastic strain energy change suddenly with increasing strength reduction coefficient. The elasto-plastic behavior of the dam foundation was idealized using Drucker–Prager yield criterion based on associated flow rule assumption. Through the static, dynamic strength reduction analysis and dynamic linear elastic analysis of the overflow dam monolith of a high gravity dam, the results’ reliability of elastic-plastic time history analysis was confirmed. The results also showed that the rock mass strength of the high gravity dam foundation has higher strength reserve coefficient. The instability criterions of dynamic strength reduction method proposed were feasible. Although the static anti-slide analysis methods and standards of gravity dam based on the numerical methods are being discussed at present, the dynamic calculation method and instability criterions proposed in this paper would provide some meaningful suggestions for the dynamic analysis of the similar projects.

  5. 磁流变液动态屈服行为的随机多尺度建模%Stochastic Multiscale Model for Dynamic Yield Behavior of Magnetorheological Fluids

    Institute of Scientific and Technical Information of China (English)

    李杰; 彭勇波

    2012-01-01

    根据能量保守原理,将微观粒子运动的动能等效成宏观动态屈服的应变能,建立内秉悬浮粒子运动涨落的磁流变液剪切应力的随机多尺度模型.分析表明,悬浮粒子初始随机条件和Brownian运动,以及剪切应变加载过程中,链簇反复断裂、重组的先后次序和数目不均匀,导致系统宏观屈服性态的非线性涨落和随机涨落;同时,微观运动涨落在体积平均过程中被严重弱化,宏观随机涨落相对不明显.拟合Bingham剪变率本构模型则进一步表明,外加场强对宏观屈服性态的变异性有一定程度的影响,磁流变液装置设计中应该考虑物理参数的随机性.%Dynamic yield behavior of magnetorheological fluids is investigated by upscaling information of microscale interaction between particles, employing a large-scale molecular dynamical simulation technique, to macroscale bulk behavior. We conduct a stochastic multiscale model for dynamic yield of magnetorheological fluids based on equivalence of system energy at different scales. It is revealed that the dynamic yield exhibits nonlinear and stochastic fluctuations due to heterogeneity of sequence and number of cluster-sheet reconstructions under shear fields loading, as well as Brownian motion of suspensions with initial random conditions. Meanwhile, we investigate fluctuation of microscale particle motions, relationship between stress and strain, and constitutive relationship of shear rate. It is noted that the microscale thermal fluctuation is far more than macroscale variations since the upscaling from microscale to macroscale results in degradation of fluctuations. Besides, the macroscale variations relies on external magnetic field as in the constitutive relationship of shear rate, I. E. Bingham model, which is supposed to be considered in the design and optimization of magnetorheological devices.

  6. A conjugacy criterion for Hall subgroups in finite groups

    CERN Document Server

    Revin, D O

    2010-01-01

    A finite group $G$ is said to satisfy $C_\\pi$ for a set of primes $\\pi$, if $G$ possesses exactly one class of conjugate $\\pi$-Hall subgroups. In the paper we obtain a criterion for a finite group $G$ to satisfy $C_\\pi$ in terms of a normal series of the group.

  7. The criterion of pulse reconstruction quality based on Wigner representation

    NARCIS (Netherlands)

    Yeremenko, S.; Baltuska, A.; Pshenichnikov, M.S; Wiersma, D. A.

    2000-01-01

    We propose a new criterion for the assessment of ultrashort pulse reconstruction quality. Our idea is based on the use of a two-dimensional Wigner representation of the electric field. This allows introducing a single measure to represent the quality of both phase and amplitude retrieval. The new cr

  8. An Elementary Proof of a Criterion for Linear Disjointness

    Science.gov (United States)

    Dobbs, David E.

    2013-01-01

    An elementary proof using matrix theory is given for the following criterion: if "F"/"K" and "L"/"K" are field extensions, with "F" and "L" both contained in a common extension field, then "F" and "L" are linearly disjoint over "K" if (and only if) some…

  9. Decision models for use with criterion-referenced tests

    NARCIS (Netherlands)

    van der Linden, Willem J.

    1980-01-01

    The problem of mastery decisions and optimizing cutoff scores on criterion-referenced tests is considered. This problem can be formalized as an (empirical) Bayes problem with decisions rules of a monotone shape. Next, the derivation of optimal cutoff scores for threshold, linear, and normal ogive lo

  10. Slope stability analysis using limit equilibrium method in nonlinear criterion.

    Science.gov (United States)

    Lin, Hang; Zhong, Wenwen; Xiong, Wei; Tang, Wenyu

    2014-01-01

    In slope stability analysis, the limit equilibrium method is usually used to calculate the safety factor of slope based on Mohr-Coulomb criterion. However, Mohr-Coulomb criterion is restricted to the description of rock mass. To overcome its shortcomings, this paper combined Hoek-Brown criterion and limit equilibrium method and proposed an equation for calculating the safety factor of slope with limit equilibrium method in Hoek-Brown criterion through equivalent cohesive strength and the friction angle. Moreover, this paper investigates the impact of Hoek-Brown parameters on the safety factor of slope, which reveals that there is linear relation between equivalent cohesive strength and weakening factor D. However, there are nonlinear relations between equivalent cohesive strength and Geological Strength Index (GSI), the uniaxial compressive strength of intact rock σ ci , and the parameter of intact rock m i . There is nonlinear relation between the friction angle and all Hoek-Brown parameters. With the increase of D, the safety factor of slope F decreases linearly; with the increase of GSI, F increases nonlinearly; when σ ci is relatively small, the relation between F and σ ci is nonlinear, but when σ ci is relatively large, the relation is linear; with the increase of m i , F decreases first and then increases.

  11. Lost-sales inventory systems with a service level criterion

    NARCIS (Netherlands)

    Bijvank, Marco; Vis, Iris F. A.

    2012-01-01

    Competitive retail environments are characterized by service levels and lost sales in case of excess demand. We contribute to research on lost-sales models with a service level criterion in multiple ways. First, we study the optimal replenishment policy for this type of inventory system as well as

  12. Satisfying the Einstein-Podolsky-Rosen criterion with massive particles

    DEFF Research Database (Denmark)

    Peise, Jan; Kruse, I.; Lange, K.;

    2016-01-01

    In 1935, Einstein, Podolsky and Rosen (EPR) questioned the completeness of quantum mechanics by devising a quantum state of two massive particles with maximally correlated space and momentum coordinates. The EPR criterion qualifies such continuous-variable entangled states, as shown successfully...

  13. Criterion-based laparoscopic training reduces total training time

    NARCIS (Netherlands)

    Brinkman, W.M.; Buzink, S.N.; Alevizos, L.; De Hingh, I.H.J.T.; Jakimowicz, J.J.

    2011-01-01

    The benefits of criterion-based laparoscopic training over time-oriented training are unclear. The purpose of this study is to compare these types of training based on training outcome and time efficiency. Methods During four training sessions within 1 week (one session per day) 34 medical interns (

  14. Criterion-based laparoscopic training reduces total training time

    NARCIS (Netherlands)

    Brinkman, W.M.; Buzink, S.N.; Alevizos, L.; De Hingh, I.H.J.T.; Jakimowicz, J.J.

    2012-01-01

    The benefits of criterion-based laparoscopic training over time-oriented training are unclear. The purpose of this study is to compare these types of training based on training outcome and time efficiency. Methods During four training sessions within 1 week (one session per day) 34 medical interns (

  15. Alignment of Lyapunov Vectors: A Quantitative Criterion to Predict Catastrophes?

    Science.gov (United States)

    Beims, Marcus W; Gallas, Jason A C

    2016-11-15

    We argue that the alignment of Lyapunov vectors provides a quantitative criterion to predict catastrophes, i.e. the imminence of large-amplitude events in chaotic time-series of observables generated by sets of ordinary differential equations. Explicit predictions are reported for a Rössler oscillator and for a semiconductor laser with optoelectronic feedback.

  16. Alignment of Lyapunov Vectors: A Quantitative Criterion to Predict Catastrophes?

    Science.gov (United States)

    Beims, Marcus W.; Gallas, Jason A. C.

    2016-11-01

    We argue that the alignment of Lyapunov vectors provides a quantitative criterion to predict catastrophes, i.e. the imminence of large-amplitude events in chaotic time-series of observables generated by sets of ordinary differential equations. Explicit predictions are reported for a Rössler oscillator and for a semiconductor laser with optoelectronic feedback.

  17. A convenient accuracy criterion for time domain FE-calculations

    DEFF Research Database (Denmark)

    Jensen, Morten Skaarup

    1997-01-01

    An accuracy criterion that is well suited to tome domain finite element (FE) calculations is presented. It is then used to develop a method for selecting time steps and element meshes that produce accurate results without significantly overburderning the computer. Use of this method is illustrate...

  18. Creativity.4in1: Four-Criterion Construct of Creativity

    Science.gov (United States)

    Kharkhurin, Anatoliy V.

    2014-01-01

    The purpose of this theoretical article is to provide an extended definition of creativity that embraces potential cross-cultural variations in this construct. Creativity is defined as a 4-criterion construct, which includes attributes of novelty, utility, aesthetics, and authenticity. Novelty attribute stipulates that a creative work brings…

  19. Criterion-based laparoscopic training reduces total training time

    NARCIS (Netherlands)

    Brinkman, W.M.; Buzink, S.N.; Alevizos, L.; De Hingh, I.H.J.T.; Jakimowicz, J.J.

    2012-01-01

    The benefits of criterion-based laparoscopic training over time-oriented training are unclear. The purpose of this study is to compare these types of training based on training outcome and time efficiency. Methods During four training sessions within 1 week (one session per day) 34 medical interns

  20. Criterion-based laparoscopic training reduces total training time

    NARCIS (Netherlands)

    Brinkman, W.M.; Buzink, S.N.; Alevizos, L.; De Hingh, I.H.J.T.; Jakimowicz, J.J.

    2011-01-01

    The benefits of criterion-based laparoscopic training over time-oriented training are unclear. The purpose of this study is to compare these types of training based on training outcome and time efficiency. Methods During four training sessions within 1 week (one session per day) 34 medical interns

  1. Orthogonality criterion for banishing hydrino states from standard quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Antonio S. de [Universidade de Coimbra, Centro de Fisica Computacional, P-3004-516 Coimbra (Portugal); UNESP, Campus de Guaratingueta, Departamento de Fisica e Quimica, 12516-410 Guaratingueta SP (Brazil)], E-mail: castro@pesquisador.cnpq.br

    2007-10-01

    Orthogonality criterion is used to show in a very simple and general way that anomalous bound-state solutions for the Coulomb potential (hydrino states) do not exist as bona fide solutions of the Schroedinger, Klein-Gordon and Dirac equations.

  2. An individual-based population dynamic model for estimating biomass yield and nutrient fluxes through an off-shore mussel ( Mytilus galloprovincialis) farm

    Science.gov (United States)

    Brigolin, Daniele; Maschio, Gabriele Dal; Rampazzo, Federico; Giani, Michele; Pastres, Roberto

    2009-04-01

    The fluxes of carbon, nitrogen and phosphorus through an off-shore long-line Mytilus galloprovincialis farm during a typical rearing cycle were estimated by combining a simple population dynamic model, based on a new individual model, and a set of field data, concerning the composition of the seston, as well as that of mussel meat and faeces. The individual model, based on an energy budget, was validated against a set of original field data, which were purposely collected from July 2006 to May 2007 in the North-Western Adriatic Sea (Italy) and was further tested using historical data. The model was upscaled to the population level by means of a set of Monte Carlo simulations, which were used for estimating the size structure of the population. The daily fluxes of C, N and P associated with mussel filtration, excretion and faeces and pseudo-faeces production were integrated over the 10-month-long rearing cycle and compared with the total amount of C, N and P removed by harvesting. The results indicate that the individual model compares well with an existing literature model and provides reliable estimations of the growth of mussel specimen over a range of trophic conditions which are typical of the Northern Adriatic Sea coastal area. The results of the budget calculation indicate that, even though the harvest represents a net removal of phosphorus and nitrogen from the ecosystem, the mussel farm increases the retention time of both nutrients in the coastal area, via the deposition of faeces and pseudo-faeces on the sea-bed. In fact, the amount of nitrogen associated with deposition is approximately twice the harvested one and the amount of phosphorus is approximately five times higher. These findings are in qualitative agreement with the results of literature budget and model calculations carried out in a temperate coastal embayment. This agreement suggests that the proper assessment of the overall effect of long-line mussel farming on both the benthic and pelagic

  3. Prediction of gasoline yield in a fluid catalytic cracking (FCC riser using k-epsilon turbulence and 4-lump kinetic models: A computational fluid dynamics (CFD approach

    Directory of Open Access Journals (Sweden)

    Muhammad Ahsan

    2015-07-01

    Full Text Available Fluid catalytic cracking (FCC is an essential process for the conversion of gas oil to gasoline. This study is an effort to model the phenomenon numerically using commercial computational fluid dynamics (CFD software, heavy density catalyst and 4-lump kinetic model. Geometry, boundary conditions and dimensions of industrial riser for catalytic cracking unit are conferred for 2D simulation using commercial CFD code FLUENT 6.3. Continuity, momentum, energy and species transport equations, applicable to two phase solid and gas flow, are used to simulate the physical phenomenon as efficient as possible. This study implements and predicts the use of the granular Eulerian multiphase model with species transport. Time accurate transient problem is solved with the prediction of mass fraction profiles of gas oil, gasoline, light gas and coke. The output curves demonstrate the breaking of heavy hydrocarbon in the presence of catalyst. An approach proposed in this study shows good agreement with the experimental and numerical data available in the literature.

  4. 不同采收期紫锥菊产量及菊苣酸动态变化研究%Dynamic changes of yield and cichoric acid content in Echinacea purpurea at different harvest time

    Institute of Scientific and Technical Information of China (English)

    陈荣; 杨跃生; 吴鸿

    2012-01-01

    Objective To investigate the influence of different harvest time on yield and cichoric acid content of Echinacea purpurea. Methods Yield and phenophase at different harvest time were observed and dynamic changes of cichoric acid in E. purpurea were studied using HPLC. Results The highest yield in the aerial parts of annual E. purpurea was obtained on Nov. 2nd when fruits matured, which was 38.3% higher than that in the blossom peak; The highest yield in underground parts was obtained on Sep. 15 at the peak of blossom and from then to Nov. 2nd when fruits matured the yield dropped slightly; The content of cichoric acid in the aerial parts was almost stable from July 10th when flower buds initiated to Sep. 27th at the peak of blossom, followed by a dropping period from Sep. 27th to Oct. 20th when fruits developing and an increasing period from Oct. 20th to Nov. 2nd. The change trend of cichoric acid in the underground parts was similar to that in the aerial parts. The changes of yield and cichoric acid content in biennial E. purpurea were almost the same as annual E. purpurea, but the highest yield in the underground parts was achieved at the time when fruits matured, and the total yield in the whole plant was 2.7 times as much as that in annual E. purpurea. The highest yield of cichoric acid was obtained both in annual and biennial E. purpurea at the time when fruits matured. Conclusion The suitable harvest time of E. purpurea in Guangzhou is at fruit mature period, and two-year cultivation is more reasonable than one-year.%目的 研究不同采收期紫锥菊质量和产量的变化.方法 通过对不同采收期的紫锥菊进行产量测定和物候期观察,并采用HPLC法对紫锥菊中的菊苣酸进行动态变化研究.结果 一年生紫锥菊地上部分的产量以11月2日(果熟期)采收的最高,比盛花期产量高38.3%,地下部分产量以9月15日(盛花期)采收的最高,从9月15日到11月2日地下部分产量有少量的降低,

  5. A generalized Nadai failure criterion for both crystalline and clastic rocks based on true triaxial tests

    Science.gov (United States)

    Haimson, Bezalel; Chang, Chandong; Ma, Xiaodong

    2016-04-01

    The UW true triaxial testing system enables the application of independent compressive loads to cuboidal specimens (19×19×38 mm) along three principal directions. We used the apparatus to conduct extensive series of experiments in three crystalline rocks (Westerly granite, KTB amphibolite, and SAFOD granodiorite) and three clastic rocks of different porosities [TCDP siltstone (7%), Coconino sandstone (17%), and Bentheim sandstone (24%)]. For each rock, several magnitudes of σ3 were employed, between 0 MPa and 100-160 MPa, and for every σ3, σ2 was varied from test to test between σ2 = σ3 and σ2=(0.4 to 1.0) σ1.Testing consisted of keeping σ2and σ3constant, and raising σ1to failure (σ1,peak). The results, plotted as σ1,peakvs. σ2for each σ3 used, highlight the undeniable effect of σ2on the compressive failure of rocks. For each level of σ3, the lowest σ2 tested (σ2 = σ3) yielded the data point used for conventional-triaxial failure criterion. However, for the same σ3 and depending on σ2 magnitude, the maximum stress bringing about failure (σ1,peak) may be considerably higher, by as much as 50% in crystalline rocks, or 15% in clastic rocks, over that in a conventional triaxial test. An important consequence is that use of a Mohr-type criterion leads to overly conservative predictions of failure. The true triaxial test results demonstrate that a criterion in terms of all (three principal stresses is necessary to characterize failure. Thus, we propose a 'Generalized Nadai Criterion' (GNC) based on Nadai (1950), i.e. expressed in terms of the two stress invariants at failure (f), τoct,f = βσoct,f, where τoct,f = 1/3[(σ1,peak -σ2)2+(σ2 -σ3)2+(σ3 -σ1,peak)2]0.5 and σoct,f = (σ1,peak + σ2 + σ3)/3, and β is a function that varies from rock to rock. Moreover, the criterion depends also on the relative magnitude of σ2, represented by a parameter b [= (σ2 - σ3)/(σ1,peak - σ3)]. For each octahedral shear stress at failure (

  6. A criterion for timescale decomposition of external inputs for generalized phase reduction of limit-cycle oscillators

    CERN Document Server

    Kurebayashi, Wataru; Nakao, Hiroya

    2015-01-01

    The phase reduction method is a dimension reduction method for weakly driven limit-cycle oscillators, which has played an important role in the theoretical analysis of synchro- nization phenomena. Recently, we proposed a generalization of the phase reduction method [W. Kurebayashi et al., Phys. Rev. Lett. 111, 2013]. This generalized phase reduction method can robustly predict the dynamics of strongly driven oscillators, for which the conventional phase reduction method fails. In this generalized method, the external input to the oscillator should be properly decomposed into a slowly varying component and remaining weak fluctua- tions. In this paper, we propose a simple criterion for timescale decomposition of the external input, which gives accurate prediction of the phase dynamics and enables us to systematically apply the generalized phase reduction method to a general class of limit-cycle oscillators. The validity of the criterion is confirmed by numerical simulations.

  7. Ovarian Follicular Dynamics, Ovarian Follicular Growth, Oocyte Yield, Embryo Production and Repeated Oocyte Pick Up in Thai Native Heifers Undergoing Superstimulation

    Directory of Open Access Journals (Sweden)

    J. Chasombat

    2013-04-01

    Full Text Available The objective of this study was to compare the effectiveness of the protocols for superstimulation of follicular growth in Thai native heifers. Heifers (n = 20 were randomly divided into four groups of five heifers/group. Heifers were given a single dose by i.m. administration of 100 mg Follicle Stimulating Hormone dissolved in polyvinylpyrrolidone (FSHp at 24 h. Ovum pick up (OPU occurred at 72 h (F24O72 protocol; Group 1 or 96 h (F24O96 protocol; Group 2, and at 36 h and OPU at 72 h (F36O72 protocol; Group 3 or 96 h (F36O96 protocol; Group 4 after follicular ablation. The dynamics of ovarian follicular growth were monitored by twice-daily ultrasonographic examinations. Blood sample collections were performed every 12 h after initiation of treatment for assessment of FSH, E2 and P4 profiles. All heifers were subjected to eight repeated sequential sessions of OPU. The follicular deviation commenced 24±5.32 h after follicular ablation in all groups. The circulatory FSH surged quickly from 24 to 36 h (>0.8 ng/ml after follicular ablation and circulatory estrogen levels steadily increased from 36 h until OPU in all groups. At the end of the OPU sessions, the mean number of aspirated follicles/heifer/session in F36O72 protocol (Group 3 and F36O96 protocol (Group 4 were higher than in the two other groups (p<0.05. The number of cumulus-oocyte complexes (COCs, cleaved and day 8 blastocysts rates in the F36O72 protocol (Group 3 were higher than in the other groups (p<0.05. It can be concluded that a single dose i.m. administration of 100 mg FSHp at 36 h and OPU at 72 h after follicular ablation (F36O72 protocol; Group 3 was the most effective protocol for superstimulation of follicular growth for repeated OPU and subsequent in vitro embryo production in Thai native heifers.

  8. A nonlinear viscoelastic constitutive equation - Yield predictions in multiaxial deformations

    Science.gov (United States)

    Shay, R. M., Jr.; Caruthers, J. M.

    1987-01-01

    Yield stress predictions of a nonlinear viscoelastic constitutive equation for amorphous polymer solids have been obtained and are compared with the phenomenological von Mises yield criterion. Linear viscoelasticity theory has been extended to include finite strains and a material timescale that depends on the instantaneous temperature, volume, and pressure. Results are presented for yield and the correct temperature and strain-rate dependence in a variety of multiaxial deformations. The present nonlinear viscoelastic constitutive equation can be formulated in terms of either a Cauchy or second Piola-Kirchhoff stress tensor, and in terms of either atmospheric or hydrostatic pressure.

  9. ٍEffect of potassium and calcium application on water use and fruit yield of tomato in a hydroponic system with dynamic and non-uniform distribution of salts

    Directory of Open Access Journals (Sweden)

    A.A. Moezzi

    2012-03-01

    % of nutrient solution with saline water, respectively. According to the results of this study, in case of dynamic and non-uniform distribution of salts in the root media, by addition of Ca to the saline solution, it would be possible to replace about half of the crop water demand with saline water, with no significant fruit yield reduction.

  10. Considerations on elliptical failure envelope associated to Mohr-Coulomb criterion

    Science.gov (United States)

    Comanici, A. M.; Barsanescu, P. D.

    2016-08-01

    Mohr-Coulomb theory is mostly used in civil engineering as it is suitable for soils, rock, concretes, etc., meaning that the theory is generally used for brittle facture of the materials, but there are cases when it matches ductile behaviour also. The failure envelope described by the Mohr-Coulomb criterion is not completely accurate to the real yield envelope. The ductile or brittle behaviour of materials could not be incorporated in a linear envelope suggested by classic stress state theories and so, there have been a number of authors who have refined the notion of yield envelope so that it would fit better to the actual behaviour of materials. The need of a realistic yield envelope comes from the demand that the failure state should be able to be predicted in a fair manner and with as little errors as possible. Of course, certain criteria will be closer to the actual situation, but there is a constant need to unify and refine the limit stress theories in order to avoid problems as defining boundaries of application areas on numerical programs. Mohr-Coulomb's yield envelope is the most used one on programs, can be reduced to Tresca theory when the materials are conducting a ductile behaviour and has a linear simplified form. The paper presents some considerations with respect to the elliptical failure envelope correlated to the Mohr-Coulomb theory. The equations have been rewritten for triaxial situation to describe a more accurate state of stress that is encountered under real conditions in materials. Using the Mohr's circles to define the yield envelope, the calculus has been made in in order to determine the yield stress at tensile tests

  11. When do perturbative approaches accurately capture the dynamics of complex quantum systems?

    Science.gov (United States)

    Fruchtman, Amir; Lambert, Neill; Gauger, Erik M.

    2016-06-01

    Understanding the dynamics of higher-dimensional quantum systems embedded in a complex environment remains a significant theoretical challenge. While several approaches yielding numerically converged solutions exist, these are computationally expensive and often provide only limited physical insight. Here we address the question: when do more intuitive and simpler-to-compute second-order perturbative approaches provide adequate accuracy? We develop a simple analytical criterion and verify its validity for the case of the much-studied FMO dynamics as well as the canonical spin-boson model.

  12. Subsequent yield loci of 5754O aluminum alloy sheet

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-bo; WAN Min; WU Xiang-dong; YAN Yu

    2009-01-01

    Complex loading paths were realized with cruciform specimens and biaxial loading testing machine. Experimental method for determining the subsequent yield locus of sheet metal was established. With this method, the subsequent yield loci of 5754O aluminum alloy sheet were obtained under complex loading paths. Theoretical subsequent yield loci based on Yld2000-2d yield criterion and three kinds of hardening modes were calculated and compared with the experimental results. The results show that the theoretical subsequent yield loci based on mixed hardening mode describe the experimental subsequent yield loci well, whereas isotropic hardening mode, which is widely used in sheet metal forming fields, predicts values larger than the experimental results. Kinematic hardening mode predicts values smaller than the experimental results and its errors are the largest.

  13. Canopy Temperature Depression as a Potential Selection Criterion for Drought Resistance in Wheat

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    (R2=0.46-0.58) conditions. These results clearly indicated grain yield and water stress can be predicted by taking CTD values in field, which can be used by breeding programs as a potential selection criterion for grain yield and drought resistance in wheat, but a second study year is needed to confirm further.

  14. The Maximum Effective Moment Criterion (MEMC) and Its Implications in Structural Geology

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The Mohr-Coulomb criterion has been widely used to explain formation of fractures.However, it fails to explain large strain deformation that widely occurs in nature. There is presently a σ1-σ3 represents the yield strength of the related rock, L is a unit length and α is the angle between σ1and deformation bands. This criterion demonstrates that the maximum value appears at angles of ±54.7° to σ1 and there is a slight difference in the moment in the range of 55°±10°. The range covers the whole observations available from nature and experiments. Its major implications include: (1) it can be used to determine the stress state when the related deformation features formed; (2) it provides a new approach to determine the Wk of the related ductile shear zone if only the ratio of the vorticity and strain rate remains fixed; (3) It can be used to explain (a) the obtuse angle in the contraction direction of conjugate kink-bands and extensional crenulation cleavages, (b) formation of low-angle normal faults and high-angle reverse faults, (c) lozenge ductile shear zones in basement terranes, (d) some crocodile structures in seismic profiles and (e) detachment folds in foreland basins.

  15. High-dynamic-range neutron time-of-flight detector used to infer the D(t,n){sup 4}He and D(d,n){sup 3}He reaction yield and ion temperature on OMEGA

    Energy Technology Data Exchange (ETDEWEB)

    Forrest, C. J., E-mail: cforrest@lle.rochester.edu; Glebov, V. Yu.; Goncharov, V. N.; Knauer, J. P.; Radha, P. B.; Regan, S. P.; Romanofsky, M. H.; Sangster, T. C.; Shoup, M. J.; Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623-1299 (United States)

    2016-11-15

    Upgraded microchannel-plate–based photomultiplier tubes (MCP-PMT’s) with increased stability to signal-shape linearity have been implemented on the 13.4-m neutron time-of-flight (nTOF) detector at the Omega Laser Facility. This diagnostic uses oxygenated xylene doped with diphenyloxazole C{sub 15}H{sub 11}NO + p-bis-(o-methylstyryl)-benzene (PPO + bis-MSB) wavelength shifting dyes and is coupled through four viewing ports to fast-gating MCP-PMT’s, each with a different gain to allow one to measure the light output over a dynamic range of 1 × 10{sup 6}. With these enhancements, the 13.4-m nTOF can measure the D(t,n){sup 4}He and D(d,n){sup 3}He reaction yields and average ion temperatures in a single line of sight. Once calibrated for absolute neutron sensitivity, the nTOF detectors can be used to measure the neutron yield from 1 × 10{sup 9} to 1 × 10{sup 14} and the ion temperature with an accuracy approaching 5% for both the D(t,n){sup 4}He and D(d,n){sup 3}He reactions.

  16. High-dynamic-range neutron time-of-flight detector used to infer the D(t,n)(4)He and D(d,n)(3)He reaction yield and ion temperature on OMEGA.

    Science.gov (United States)

    Forrest, C J; Glebov, V Yu; Goncharov, V N; Knauer, J P; Radha, P B; Regan, S P; Romanofsky, M H; Sangster, T C; Shoup, M J; Stoeckl, C

    2016-11-01

    Upgraded microchannel-plate-based photomultiplier tubes (MCP-PMT's) with increased stability to signal-shape linearity have been implemented on the 13.4-m neutron time-of-flight (nTOF) detector at the Omega Laser Facility. This diagnostic uses oxygenated xylene doped with diphenyloxazole C15H11NO + p-bis-(o-methylstyryl)-benzene (PPO + bis-MSB) wavelength shifting dyes and is coupled through four viewing ports to fast-gating MCP-PMT's, each with a different gain to allow one to measure the light output over a dynamic range of 1 × 10(6). With these enhancements, the 13.4-m nTOF can measure the D(t,n)(4)He and D(d,n)(3)He reaction yields and average ion temperatures in a single line of sight. Once calibrated for absolute neutron sensitivity, the nTOF detectors can be used to measure the neutron yield from 1 × 10(9) to 1 × 10(14) and the ion temperature with an accuracy approaching 5% for both the D(t,n)(4)He and D(d,n)(3)He reactions.

  17. High-dynamic-range neutron time-of-flight detector used to infer the D(t,n)4He and D(d,n)3He reaction yield and ion temperature on OMEGA

    Science.gov (United States)

    Forrest, C. J.; Glebov, V. Yu.; Goncharov, V. N.; Knauer, J. P.; Radha, P. B.; Regan, S. P.; Romanofsky, M. H.; Sangster, T. C.; Shoup, M. J.; Stoeckl, C.

    2016-11-01

    Upgraded microchannel-plate-based photomultiplier tubes (MCP-PMT's) with increased stability to signal-shape linearity have been implemented on the 13.4-m neutron time-of-flight (nTOF) detector at the Omega Laser Facility. This diagnostic uses oxygenated xylene doped with diphenyloxazole C15H11NO + p-bis-(o-methylstyryl)-benzene (PPO + bis-MSB) wavelength shifting dyes and is coupled through four viewing ports to fast-gating MCP-PMT's, each with a different gain to allow one to measure the light output over a dynamic range of 1 × 106. With these enhancements, the 13.4-m nTOF can measure the D(t,n)4He and D(d,n)3He reaction yields and average ion temperatures in a single line of sight. Once calibrated for absolute neutron sensitivity, the nTOF detectors can be used to measure the neutron yield from 1 × 109 to 1 × 1014 and the ion temperature with an accuracy approaching 5% for both the D(t,n)4He and D(d,n)3He reactions.

  18. An important reference criterion for the selection of GSSP

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A study on the relationship between biostratigraphy and sequence stratigraphy in several designated global boundary stratotypes shows that the best way may be to take the GSSP at a point coincident with the base of the first widespread Leading Group biozone above the first flooding surface (FFS) of the relevant third-order sequence.It is suggested that the first flooding surface of the sequence should be an important reference criterion for the selection of GSSP.As the base of the first widespread Leading Group biozone chosen for the definition of GSSP could not be lower than the first flooding surface of the referred sequence,the latter surface may be an important criterion for the recognition and correlation of the chronostratigraphic boundaries.

  19. A Generalized Evolution Criterion in Nonequilibrium Convective Systems

    Science.gov (United States)

    Ichiyanagi, Masakazu; Nisizima, Kunisuke

    1989-04-01

    A general evolution criterion, applicable to transport processes such as the conduction of heat and mass diffusion, is obtained as a direct version of the Le Chatelier-Braun principle for stationary states. The present theory is not based on any radical departure from the conventional one. The generalized theory is made determinate by proposing the balance equations for extensive thermodynamic variables which will reflect the character of convective systems under the assumption of local equilibrium. As a consequence of the introduction of source terms in the balance equations, there appear additional terms in the expression of the local entropy production, which are bilinear in terms of the intensive variables and the sources. In the present paper, we show that we can construct a dissipation function for such general cases, in which the premises of the Glansdorff-Prigogine theory are accumulated. The new dissipation function permits us to formulate a generalized evolution criterion for convective systems.

  20. Logical and Decisive Combining Criterion for Binary Group Decision Making

    Directory of Open Access Journals (Sweden)

    Ivan Vrana

    2010-04-01

    Full Text Available A new combining criterion, the Multiplicative Proportional Deviative Influence (MPDI is presented for combining or aggregating multi-expert numerical judgments in Yes-or-No type ill-structured group decision making situations. This newly proposed criterion performs well in comparison with the widely used aggregation means: the Arithmetic Mean (AM, and Geometric Mean (GM, especially in better reflecting the degree of agreement between criteria levels or numerical experts’ judgments. The MPDI can be considered as another class of combining criteria that make effect of the degree of agreement among multiple numerical judgments. The MPDI is applicable in integrating several collaborative or synergistic decision making systems through combining final numerical decision outputs. A discussion and generalization of the proposed MPDI is discussed withnumerical example.

  1. Bayesian Case-deletion Model Complexity and Information Criterion.

    Science.gov (United States)

    Zhu, Hongtu; Ibrahim, Joseph G; Chen, Qingxia

    2014-10-01

    We establish a connection between Bayesian case influence measures for assessing the influence of individual observations and Bayesian predictive methods for evaluating the predictive performance of a model and comparing different models fitted to the same dataset. Based on such a connection, we formally propose a new set of Bayesian case-deletion model complexity (BCMC) measures for quantifying the effective number of parameters in a given statistical model. Its properties in linear models are explored. Adding some functions of BCMC to a conditional deviance function leads to a Bayesian case-deletion information criterion (BCIC) for comparing models. We systematically investigate some properties of BCIC and its connection with other information criteria, such as the Deviance Information Criterion (DIC). We illustrate the proposed methodology on linear mixed models with simulations and a real data example.

  2. Adaptive Linear Filtering Design with Minimum Symbol Error Probability Criterion

    Institute of Scientific and Technical Information of China (English)

    Sheng Chen

    2006-01-01

    Adaptive digital filtering has traditionally been developed based on the minimum mean square error (MMSE)criterion and has found ever-increasing applications in communications. This paper presents an alternative adaptive filtering design based on the minimum symbol error rate (MSER) criterion for communication applications. It is shown that the MSER filtering is smarter, as it exploits the non-Gaussian distribution of filter output effectively. Consequently, it provides significant performance gain in terms of smaller symbol error over the MMSE approach. Adopting Parzen window or kernel density estimation for a probability density function, a block-data gradient adaptive MSER algorithm is derived. A stochastic gradient adaptive MSER algorithm, referred to as the least symbol error rate, is further developed for sampleby-sample adaptive implementation of the MSER filtering. Two applications, involving single-user channel equalization and beamforming assisted receiver, are included to demonstrate the effectiveness and generality of the proposed adaptive MSER filtering approach.

  3. A HYBRID DYNAMIC PROGRAM SLICING

    Institute of Scientific and Technical Information of China (English)

    Yi Tong; Wu Fangjun

    2005-01-01

    This letter proposes a hybrid method for computing dynamic program slicing. The key element is to construct a Coverage-Testing-based Dynamic Dependence Graph (CTDDG),which makes use of both dynamic and static information to get execution status. The approach overcomes the limitations of previous dynamic slicing methods, which have to redo slicing if slice criterion changes.

  4. Large, moderate, small earthquakes and seismic fortification criterion

    Institute of Scientific and Technical Information of China (English)

    沈建文; 石树中

    2004-01-01

    This paper discusses the relation between two-step seismic design and the standard of probability of exceedance, and the relation of three-levels seismic ground motion parameters given by probability method and comprehensive probability method. The relative size relations of the ground motions with 2%, 10%, 63% probability of exceedance in 50 years, namely "large earthquake","moderate earthquake", and "small earthquake", are discussed through a practical example of seismic hazard analysis. The methods to determine seismic fortification criterion are discussed.

  5. Convergent, discriminant, and criterion validity of DSM-5 traits.

    Science.gov (United States)

    Yalch, Matthew M; Hopwood, Christopher J

    2016-10-01

    Section III of the Diagnostic and Statistical Manual of Mental Disorders (5th edi.; DSM-5; American Psychiatric Association, 2013) contains a system for diagnosing personality disorder based in part on assessing 25 maladaptive traits. Initial research suggests that this aspect of the system improves the validity and clinical utility of the Section II Model. The Computer Adaptive Test of Personality Disorder (CAT-PD; Simms et al., 2011) contains many similar traits as the DSM-5, as well as several additional traits seemingly not covered in the DSM-5. In this study we evaluate the convergent and discriminant validity between the DSM-5 traits, as assessed by the Personality Inventory for DSM-5 (PID-5; Krueger et al., 2012), and CAT-PD in an undergraduate sample, and test whether traits included in the CAT-PD but not the DSM-5 provide incremental validity in association with clinically relevant criterion variables. Results supported the convergent and discriminant validity of the PID-5 and CAT-PD scales in their assessment of 23 out of 25 DSM-5 traits. DSM-5 traits were consistently associated with 11 criterion variables, despite our having intentionally selected clinically relevant criterion constructs not directly assessed by DSM-5 traits. However, the additional CAT-PD traits provided incremental information above and beyond the DSM-5 traits for all criterion variables examined. These findings support the validity of pathological trait models in general and the DSM-5 and CAT-PD models in particular, while also suggesting that the CAT-PD may include additional traits for consideration in future iterations of the DSM-5 system. (PsycINFO Database Record

  6. On Feller's criterion for the law of the iterated logarithm

    Directory of Open Access Journals (Sweden)

    Deli Li

    1994-01-01

    Full Text Available Combining Feller's criterion with a non-uniform estimate result in the context of the Central Limit Theorem for partial sums of independent random variables, we obtain several results on the Law of the Iterated Logarithm. Two of these results refine corresponding results of Wittmann (1985 and Egorov (1971. In addition, these results are compared with the corresponding results of Teicher (1974, Tomkins (1983 and Tomkins (1990

  7. Determining threshold default risk criterion for trade credit granting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To solve the problem of setting threshold default risk criterion to select retailer eligible for trade credit granting, a novel method of solving simultaneous equations is proposed. This method is based on the bilevel programming modeling of trade credit decisions as an interaction between supplier and retailer. First, the bilevel programming is set up where the supplier decides on credit terms at the top level considering a retailer's default risk, and the retailer determines the order quantity at the lowe...

  8. Best Practices in Utilizing the Changing Criterion Design.

    Science.gov (United States)

    Klein, Liesa A; Houlihan, Daniel; Vincent, James L; Panahon, Carlos J

    2017-03-01

    The changing criterion design (CCD) has been a recognized format of single-case research for four decades. Published examples of the CCD have been limited and the structure of the design used in the literature has varied to a degree that might engender confusion. This review examines the structure of CCD studies published to date to identify prior implementation practices and identify best practices for future use.

  9. Amenorrhea as a Diagnostic Criterion for Anorexia Nervosa

    OpenAIRE

    2012-01-01

    Amenorrhea is a current criterion for the diagnosis of anorexia nervosa (AN) according to the DSM-IV-TR. Nevertheless, when comparing groups of patients who fulfill all the criteria of this manual for AN and groups of women who show them all but amenorrhea, some studies did not find significant differences in the psychopathology typically associated with AN. The purpose of our study was to compare both groups in demographic, anthropometric, psychological and psychopathological variables. Ther...

  10. Ecological criterion effect on the forest road network longitudinal gradient

    Directory of Open Access Journals (Sweden)

    Petr Hrůza

    2013-01-01

    Full Text Available The specific way in which a forest road is designed affects the management in the forest environment and timber transport. The aim of this study was to find out whether an inclusion of the ecological criterion in the forest road design will change the parameter of the longitudinal gradient of forest hauling roads and whether these changes will have an effect on the accessibility of forest stands by timber hauling machinery. The possible changes in the longitudinal gradient can also affect the technology of forest road surfacing and the selection of the appropriate surface type. We can state that an inclusion of the ecological criterion in the forest road network design will bring statistically significant changes in longitudinal gradients of forest hauling roads. The mean longitudinal gradient of the current forest road network is 2.82 % and the mean longitudinal gradient of the forest road network designed with inclusion of the ecological criterion is 4.82 %. The results show statistically significant changes in the longitudinal parameters of forest hauling roads. However, it will not bring a need for a change in construction technology, and will not affect the accessibility of forest stands by timber hauling machinery.

  11. Bayesian information criterion for longitudinal and clustered data.

    Science.gov (United States)

    Jones, Richard H

    2011-11-10

    When a number of models are fit to the same data set, one method of choosing the 'best' model is to select the model for which Akaike's information criterion (AIC) is lowest. AIC applies when maximum likelihood is used to estimate the unknown parameters in the model. The value of -2 log likelihood for each model fit is penalized by adding twice the number of estimated parameters. The number of estimated parameters includes both the linear parameters and parameters in the covariance structure. Another criterion for model selection is the Bayesian information criterion (BIC). BIC penalizes -2 log likelihood by adding the number of estimated parameters multiplied by the log of the sample size. For large sample sizes, BIC penalizes -2 log likelihood much more than AIC making it harder to enter new parameters into the model. An assumption in BIC is that the observations are independent. In mixed models, the observations are not independent. This paper develops a method for calculating the 'effective sample size' for mixed models based on Fisher's information. The effective sample size replaces the sample size in BIC and can vary from the number of subjects to the number of observations. A number of error models are considered based on a general mixed model including unstructured, compound symmetry.

  12. Tightening the Dutch coffee shop policy: Evaluation of the private club and the residence criterion.

    Science.gov (United States)

    van Ooyen-Houben, Marianne M J; Bieleman, Bert; Korf, Dirk J

    2016-05-01

    The Dutch coffee shop policy was tightened in 2012. Two additional criteria that coffee shops must adhere to in order for them to be tolerated came into force: the private club and the residence criterion. Coffee shops were only permitted to give access to members and only residents of the Netherlands were permitted to become a member. This tightened policy sought to make coffee shops smaller and more controllable, to reduce the nuisance associated with coffee shops and to reduce the number of foreign visitors attracted by the coffee shops. Enforcement began in the southern provinces. The private club criterion was abolished at the end of 2012. A sample of fourteen municipalities with coffee shops was drawn. Seven in the south were treated as an 'experimental group' and the others as 'comparison group'. A baseline assessment and follow-ups at six and 18 months were performed. A combination of methods was applied: interviews with local experts, surveys with neighbourhood residents, coffee shop visitors and cannabis users, and ethnographic field work. Drugs tourism to coffee shops swiftly declined in 2012. The coffee shops also lost a large portion of their local customers, since users did not want to register as a member. The illegal market expanded. Neighbourhood residents experienced a greater amount of nuisance caused by dealer activities. After abolishment of the private club criterion, residents of the Netherlands largely returned to the coffee shops. Drug tourists still remained largely absent. Neighbourhood residents experienced more nuisance from coffee shops again. Illegal cannabis sale was tempered. No effect on cannabis use was found. The quick and robust shifts in the users' market in reaction to the policy changes illustrate the power of policy, but also the limitations caused by the dynamic and resilient nature of the Dutch cannabis supply market. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Yield stress fluids slowly yield to analysis

    NARCIS (Netherlands)

    Bonn, D.; Denn, M.M.

    2009-01-01

    We are surrounded in everyday life by yield stress fluids: materials that behave as solids under small stresses but flow like liquids beyond a critical stress. For example, paint must flow under the brush, but remain fixed in a vertical film despite the force of gravity. Food products (such as mayon

  14. A new mixed-mode fracture criterion for large scale lattice models

    Directory of Open Access Journals (Sweden)

    T. Sachau

    2013-08-01

    Full Text Available Reasonable fracture criteria are crucial for the modeling of dynamic failure in computational spring lattice models. For experiments on the micro and on the meso scale exist successful criteria, which are based on the stress that a spring experiences. In this paper we test the applicability of these failure criteria to large scale models, where gravity plays an important role in addition to the externally applied deformation. The resulting brittle structures do not resemble the outcome predicted by fracture mechanics and geological observations. For this reason we derive an elliptical fracture criterion, which is based on the strain energy stored in a spring. Simulations using the new criterion result in realistic structures. It is another great advantage of this fracture model, that it can be combined with classic geological material parameters: the tensile strength σ0 and the shear cohesion τ0. While we tested the fracture model only for large scale structures, there is strong reason to believe that the model is equally applicable to lattice simulations on the micro and the meso scale.

  15. 基于分数阶环境热浴的非各态历经判据研究∗%Studies of nonergo dic criterion based on the fractional heat bath mo del

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The generalized Langevin equation with a power law memory kernel is derived via the gas/solid-surface model with fractional heat bath. Using Lapalce transformation, the dynamic evolution and long-time asymptotic behaviors of the gas particles occurring either in free or harmonic potentials are then investigated. In particular, the validity of three kinds of ergodic criteria is analyzed in detail, including the Khinchin criterion, Lee criterion, and the intrinsic and external behaviors. It is found that the Khinchin criterion holds for all ranges of diffusion and transport processes described by a generalized Langevin equation. Lee criterion is just applied to distinguish diffusion processes. Meanwhile, the intrinsic criterion and external behaviors can not only divide the nonergodicity into two classes but also reveal the underlying physical origins.

  16. Climatological and genetic effects on milk composition and yield.

    Science.gov (United States)

    Sharma, A K; Rodriguez, L A; Mekonnen, G; Wilcox, C J; Bachman, K C; Collier, R J

    1983-01-01

    Results confirm most other research on milk composition and yield. All responses were affected by climate, some considerably more than others, if percent of error variance is the criterion. Jersey yields were less sensitive to climate than were Holstein, but Jersey milk composition appeared more sensitive. Somatic cell count (REF), a measure of mastitis, was affected by climate but less than all other variables except protein/fat and LM%. Needed are estimates of interactions between climatic effects and response surface models to quantify possible improvement in performance following environmental modification. Genetic correlations between milk yield and REF and chloride % suggest that single trait selection for milk yield might increase incidence of mastitis although phenotypic correlations indicate that high yields and absence of mastitis are correlated.

  17. Efficient Return Algorithms For Associated Plasticity With Multiple Yield Planes

    DEFF Research Database (Denmark)

    Clausen, Johan Christian; Damkilde, Lars; Andersen, Lars

    2006-01-01

    A new return method for implicit integration of linear isotropic yield criteria is presented. The basic idea is to perform all the manipulations in the principal stress space and thereby achieve very simple formulae for calculating the plastic corrector stresses, based on the constant gradient...... of such criteria. The return formulae are in closed form and no iteration is required. The method accounts for three types of stress return: Return to a single yield plane, to a discontinuity line at the intersection of two yield planes and to a discontinuity point at the intersection between three or more yield...... planes. The infinitesimal and the consistent elastoplastic constitutive matrix are calculated for each type of stress return, as are the conditions to ascertain which type of return is required. The method is exemplified with the Mohr-Coulomb yield criterion....

  18. Kugo-Ojima confinement criterion, Zwanziger-Gribov horizon condition, and infrared critical exponents in Landau gauge QCD

    CERN Document Server

    Alkofer, R; Von Smekal, L; Alkofer, Reinhard; Fischer, Christian S.; Smekal, Lorenz von

    2003-01-01

    The Kugo-Ojima confinement criterion and its relation to the infrared behaviour of the gluon and ghost propagators in Landau gauge QCD are reviewed. The realization of this confinement criterion (which in Landau gauge relates to Zwanziger's horizon condition) results from quite general properties of the ghost Dyson-Schwinger equation. The numerical solutions for the gluon and ghost propagators obtained from a truncated set of Dyson-Schwinger equations provide an explicit example for the anticipated infrared behaviour. These results are in good agreement, also quantitatively, with corresponding lattice data obtained recently. The resulting running coupling approaches a fixed point in the infrared, $\\alpha(0) = 8.9/N_c$. Solutions for the coupled system of Dyson-Schwinger equations for the quark, gluon and ghost propagators are presented. Dynamical generation of quark masses and thus spontaneous breaking of chiral symmetry is found. In the quenched approximation the quark propagator functions agree well with th...

  19. Criterion for SLOCC equivalence of multipartite quantum states

    Science.gov (United States)

    Zhang, Tinggui; Zhao, Ming-Jing; Huang, Xiaofen

    2016-10-01

    We study the stochastic local operation and classical communication (SLOCC) equivalence for arbitrary dimensional multipartite quantum states. For multipartite pure states, we present a necessary and sufficient criterion in terms of their coefficient matrices. This condition can be used to classify some SLOCC equivalent quantum states with coefficient matrices having the same rank. For multipartite mixed state, we provide a necessary and sufficient condition by means of the realignment of matrix. Some detailed examples are given to identify the SLOCC equivalence of multipartite quantum states.

  20. Application of the Kelly Criterion to Ornstein-Uhlenbeck Processes

    Science.gov (United States)

    Lv, Yingdong; Meister, Bernhard K.

    In this paper, we study the Kelly criterion in the continuous time framework building on the work of E.O. Thorp and others. The existence of an optimal strategy is proven in a general setting and the corresponding optimal wealth process is found. A simple formula is provided for calculating the optimal portfolio for a set of price processes satisfying some simple conditions. Properties of the optimal investment strategy for assets governed by multiple Ornstein-Uhlenbeck processes are studied. The paper ends with a short discus-sion of the implications of these ideas for financial markets.

  1. Qualitative Criterion for Interception in a Pursuit/Evasion Game

    CERN Document Server

    Morgan, John A

    2009-01-01

    A qualitative account is given of a differential pursuit/evasion game. A criterion for the existence of an intercept solution is obtained using future cones that contain all attainable trajectories of target or interceptor originating from an initial position. A sufficient and necessary conditon that an opportunity to intercept always exist is that, after some initial time, the future cone of the target be contained within the future cone of the interceptor. The sufficient condition may be regarded as a kind of Nash equillibrium.

  2. Adjustment Criterion and Algorithm in Adjustment Model with Uncertain

    Directory of Open Access Journals (Sweden)

    SONG Yingchun

    2015-02-01

    Full Text Available Uncertainty often exists in the process of obtaining measurement data, which affects the reliability of parameter estimation. This paper establishes a new adjustment model in which uncertainty is incorporated into the function model as a parameter. A new adjustment criterion and its iterative algorithm are given based on uncertainty propagation law in the residual error, in which the maximum possible uncertainty is minimized. This paper also analyzes, with examples, the different adjustment criteria and features of optimal solutions about the least-squares adjustment, the uncertainty adjustment and total least-squares adjustment. Existing error theory is extended with new observational data processing method about uncertainty.

  3. Optimization of the Structures at Shakedown and Rosen's Optimality Criterion

    Science.gov (United States)

    Alawdin, Piotr; Atkociunas, Juozas; Liepa, Liudas

    2016-09-01

    Paper focuses on the problems of application of extreme energy principles and nonlinear mathematical programing in the theory of structural shakedown. By means of energy principles, which describes the true stress-strain state conditions of the structure, the dual mathematical models of analysis problems are formed (static and kinematic formulations). It is shown how common mathematical model of the structures optimization at shakedown with safety and serviceability constraints (according to the ultimate limit state (ULS) and serviceability limit state (SLS) requirements) on the basis of previously mentioned mathematical models is formed. The possibilities of optimization problem solution in the context of physical interpretation of optimality criterion of Rosen's algorithm are analyzed.

  4. Sensor Calibration Design Based on D-Optimality Criterion

    Directory of Open Access Journals (Sweden)

    Hajiyev Chingiz

    2016-09-01

    Full Text Available In this study, a procedure for optimal selection of measurement points using the D-optimality criterion to find the best calibration curves of measurement sensors is proposed. The coefficients of calibration curve are evaluated by applying the classical Least Squares Method (LSM. As an example, the problem of optimal selection for standard pressure setters when calibrating a differential pressure sensor is solved. The values obtained from the D-optimum measurement points for calibration of the differential pressure sensor are compared with those from actual experiments. Comparison of the calibration errors corresponding to the D-optimal, A-optimal and Equidistant calibration curves is done.

  5. On the Carleson measure criterion in linear systems theory

    CERN Document Server

    Haak, Bernhard Hermann

    2008-01-01

    In Ho, Russell, and Weiss, a Carleson measure criterion for admissibility of one-dimensional input elements with respect to diagonal semigroups is given. We extend their results from the Hilbert space situation $X=\\ell_2$ and $L^2$--admissibility to the more general situation of $L^p$--admissibility on $\\ell_q$--spaces. In case of analytic diagonal semigroups we present a new result that does not rely on Laplace transform methods. A comparison of both criteria leads to result of $L^p$--admissibility for reciprocal systems in the sense of Curtain.

  6. Forecastability as a Design Criterion in Wind Resource Assessment: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J.; Hodge, B. M.

    2014-04-01

    This paper proposes a methodology to include the wind power forecasting ability, or 'forecastability,' of a site as a design criterion in wind resource assessment and wind power plant design stages. The Unrestricted Wind Farm Layout Optimization (UWFLO) methodology is adopted to maximize the capacity factor of a wind power plant. The 1-hour-ahead persistence wind power forecasting method is used to characterize the forecastability of a potential wind power plant, thereby partially quantifying the integration cost. A trade-off between the maximum capacity factor and the forecastability is investigated.

  7. Critical machine cluster identification using the equal area criterion

    DEFF Research Database (Denmark)

    Weckesser, Johannes Tilman Gabriel; Jóhannsson, Hjörtur; Østergaard, Jacob

    2015-01-01

    The paper introduces a new method to early identify the critical machine cluster (CMC) after a transient disturbance. For transient stability assessment with methods based on the equal area criterion it is necessary to split the generators into a group of critical and non-critical machines...... coupling coefficient is derived and a cluster identification algorithm is developed. The algorithm determines the CMC based on the impact of the fault on the derived coupling coefficient of individual generator pairs. The results from two cases are presented and discussed, where the CMC is successfully...

  8. Local Axisymmetric Instability Criterion in the Thin, Rotating, Multicomponent Disk

    CERN Document Server

    Rafikov, R R

    2000-01-01

    Purely gravitational perturbations are considered in a thin rotating disk composed of several gas and stellar components. The dispersion relation for the axisymmetric density waves propagating through the disk is found and the criterion for the local axisymmetric stability of the whole system is formulated. In the appropriate limit of two-component gas we confirm the findings of Jog & Solomon (1984) and extend consideration to the case when one component is collisionless. Gravitational stability of the Galactic disk in the Solar neighborhood based on the multicomponent instability condition is explored using recent measurements of the stellar composition and kinematics in the local Galactic disk obtained by Hipparcos satellite.

  9. Utilization of Durability Criterion to Develop Automotive Components

    DEFF Research Database (Denmark)

    Ricardo, Luiz Carlos Hernandes

    2010-01-01

    . This paper will present a review of the techniques used in the automotive industry regarding durability before mentioned systems. The paper will present the procedures to obtain the spectrum loading to use in finite element analysis and the validation in laboratory and proving grounds.......Today the automotive companies must reduce the time to development of new products with improvement in performance, durability and low cost reductions where possible. To achieve this goal the carmakers need to improve the design criterion of car systems like body, chassis and suspension components...

  10. Recent Innovations in the Changing Criterion Design: Implications for Research and Practice in Special Education

    Science.gov (United States)

    McDougall, Dennis; Hawkins, Jacqueline; Brady, Michael; Jenkins, Amelia

    2006-01-01

    This article illustrates (a) 2 recent innovations in the changing criterion research design, (b) how these innovations apply to research and practice in special education, and (c) how clinical needs influence design features of the changing criterion design. The first innovation, the range-bound changing criterion, is a very simple variation of…

  11. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  12. An objective criterion for determining the South Atlantic Convergence Zone

    Directory of Open Access Journals (Sweden)

    Tercio eAmbrizzi

    2015-04-01

    Full Text Available The South Atlantic Convergence Zone (SACZ is the dominant summertime cloudiness feature of subtropical South America and the western South Atlantic Ocean, having a significant influence on the precipitation regime of southeastern Brazil. This paper proposes an objective criterion based mainly on precipitation, as this variable is easily obtained on general circulation models simulating past, present and future climate. Usually most SACZ studies use emerging long wave radiation as a precipitation proxy. This is enough to describe event position at first, but using precipitation would allow for better quantification, especially for climate studies, where precipitation is indispensable. An assessment was carried out to find out if classical DJF period is ideal for determining the SACZ for the present climate and future scenarios. In general the SACZ event detection criterion showed quite satisfactory results when event dates were previously known. When it was applied to future climate scenario it identified a number of events compatible with the present climate. The SACZ was well defined for both the simulated and observed precipitation data.

  13. Criterion of Turbulent Transition in Pressure Driven Flows

    Science.gov (United States)

    Dou, Hua-Shu; Khoo, Boo Cheong

    2012-11-01

    It has been found from numerical simulations and experiments that velocity inflection could result in turbulent transition in viscous parallel flows. However, there are exceptions, for example, in the plane Poiseuille-Couette flow. Thus, whether velocity inflection necessarily leads to turbulent transition is still not clear. To-date, there is still no consensus on the physics of turbulence transition in the scientific community. In this study, the mechanism of turbulent transition is investigated using the energy gradient method. It is found that the transition to turbulence from a laminar flow depends on the magnitudes of the energy gradient function and the energy of the disturbance imposed (including both the amplitude and the frequency). Our study further reveals that the criterion of turbulent transition is different in pressure and shear driven flows. In pressure driven parallel flows, it is found that the necessary and sufficient condition of turbulent transition is the existence of an inflection point on the velocity profile. This criterion is found to be consistent with the available experimental data and numerical simulation results. On contrast, velocity inflection in shear driven flows does not necessarily lead to turbulent transition.

  14. A one-class kernel fisher criterion for outlier detection.

    Science.gov (United States)

    Dufrenois, Franck

    2015-05-01

    Recently, Dufrenois and Noyer proposed a one class Fisher's linear discriminant to isolate normal data from outliers. In this paper, a kernelized version of their criterion is presented. Originally on the basis of an iterative optimization process, alternating between subspace selection and clustering, I show here that their criterion has an upper bound making these two problems independent. In particular, the estimation of the label vector is formulated as an unconstrained binary linear problem (UBLP) which can be solved using an iterative perturbation method. Once the label vector is estimated, an optimal projection subspace is obtained by solving a generalized eigenvalue problem. Like many other kernel methods, the performance of the proposed approach depends on the choice of the kernel. Constructed with a Gaussian kernel, I show that the proposed contrast measure is an efficient indicator for selecting an optimal kernel width. This property simplifies the model selection problem which is typically solved by costly (generalized) cross-validation procedures. Initialization, convergence analysis, and computational complexity are also discussed. Lastly, the proposed algorithm is compared with recent novelty detectors on synthetic and real data sets.

  15. A Multi Fluid Analysis of the Ignition Criterion

    Science.gov (United States)

    Guazzotto, Luca; Betti, Riccardo

    2016-10-01

    In magnetic confinement nuclear fusion experiments, performance with respect to ignition is expressed in terms of the Lawson criterion, a zero-dimensional, single-fluid, steady-state power balance expressing the plasma properties needed for ignition through the energy confinement time τE and the plasma temperature and density. Several improvements to the classical criterion are investigated. Ions, electrons and α particles are allowed to have different energy confinement times and energy coupling times are expressed through physics-based relations. The effect of multi-fluid physics is examined in a steady-state analysis and for the time-dependent case, which requires a nonlinear treatment more detailed than the standard `` Ṫ vs . T'' single-fluid one. A one-dimensional analysis is also considered to investigate the importance of density and temperature profiles on the τE needed for ignition. Rather than by solving the 1D transport equations, this is done with a parametric study. This work was performed under DOE Grant DE-FG02-93ER54215.

  16. Asymmetry in olfactory generalization and the inclusion criterion in ants.

    Science.gov (United States)

    Bos, Nick

    2014-01-01

    Animals constantly face the challenge of extracting important information out of their environment, and for many animals much of this information is chemical in nature. The ability to discriminate and generalize between chemical stimuli is extremely important and is commonly thought to depend mostly on the structural similarity between the different stimuli. However, we previously provided evidence that in the carpenter ant Camponotus aethiops, generalization not only depends on structural similarity, but also on the animal's previous training experience. When individual ants were conditioned to substance A, they generalized toward a mixture of A and B. However, when trained to substance B, they did not generalize toward this mixture, resulting in asymmetrical generalization. This asymmetry followed an inclusion criterion, where the ants consistently generalized from a molecule with a long carbon chain to molecules with a shorter chain, but not the other way around. Here I will review the evidence for the inclusion criterion, describe possible proximate mechanisms underlying this phenomenon as well as discuss its potential adaptive significance.

  17. SIF-based fracture criterion for interface cracks

    Science.gov (United States)

    Ji, Xing

    2016-06-01

    The complex stress intensity factor K governing the stress field of an interface crack tip may be split into two parts, i.e., hat{K} and s^{-iɛ}, so that K=hat{K}s^{-iɛ}, s is a characteristic length and ɛ is the oscillatory index. hat{K} has the same dimension as the classical stress intensity factor and characterizes the interface crack tip field. That means a criterion for interface cracks may be formulated directly with hat{K}, as Irwin (ASME J. Appl. Mech. 24:361-364, 1957) did in 1957 for the classical fracture mechanics. Then, for an interface crack, it is demonstrated that the quasi Mode I and Mode II tip fields can be defined and distinguished from the coupled mode tip fields. Built upon SIF-based fracture criteria for quasi Mode I and Mode II, the stress intensity factor (SIF)-based fracture criterion for mixed mode interface cracks is proposed and validated against existing experimental results.

  18. Karst Collapse Mechanism and Criterion for Its Stability

    Institute of Scientific and Technical Information of China (English)

    贺可强; 刘长礼; 王思敬

    2001-01-01

    Karst collapse, caused by natural or artificial abstraction of groundwater, has been a focus of environmental geological problems for its ever-increasing hazardousness. The potential erosion theory and vacuum suction erosion theory,which reveal the origin of karst collapse macroscopically, are popularly accepted. However, a mathematic prediction criterion for karst collapse cannot be established only by these two theories. From a new perspective, this paper attempts to explain the microcosmic mechanism of karst collapse on the basis of these two theories. When the shear stress surpasses the shear strength of soil, a certain point or a certain plane in the unconsolidated soil covering karst caves will fail under the mechanical effects of water and air as well as its load-pressure, and with the increase of damaged points, a breaking plane appears and the soil on karst caves is completely damaged; as a result, the karst ground collapses. On the basis of the MohrCoulomb failure theory and previous studies, the paper presents a prediction criterion of karst collapse. Finally, by taking,for example, nine typical cases of collapse caused by pumping tests in Guizhou, the paper gives the calculation process of the model and proves its reliability.``

  19. Deviance Information Criterion (DIC) in Bayesian Multiple QTL Mapping.

    Science.gov (United States)

    Shriner, Daniel; Yi, Nengjun

    2009-03-15

    Mapping multiple quantitative trait loci (QTL) is commonly viewed as a problem of model selection. Various model selection criteria have been proposed, primarily in the non-Bayesian framework. The deviance information criterion (DIC) is the most popular criterion for Bayesian model selection and model comparison but has not been applied to Bayesian multiple QTL mapping. A derivation of the DIC is presented for multiple interacting QTL models and calculation of the DIC is demonstrated using posterior samples generated by Markov chain Monte Carlo (MCMC) algorithms. The DIC measures posterior predictive error by penalizing the fit of a model (deviance) by its complexity, determined by the effective number of parameters. The effective number of parameters simultaneously accounts for the sample size, the cross design, the number and lengths of chromosomes, covariates, the number of QTL, the type of QTL effects, and QTL effect sizes. The DIC provides a computationally efficient way to perform sensitivity analysis and can be used to quantitatively evaluate if including environmental effects, gene-gene interactions, and/or gene-environment interactions in the prior specification is worth the extra parameterization. The DIC has been implemented in the freely available package R/qtlbim, which greatly facilitates the general usage of Bayesian methodology for genome-wide interacting QTL analysis.

  20. A procedure for seiche analysis with Bayesian information criterion

    Science.gov (United States)

    Aichi, Masaatsu

    2016-04-01

    Seiche is a standing wave in enclosed or semi-enclosed water body. Its amplitude irregularly changes in time due to weather condition etc. Then, extracting seiche signal is not easy by usual methods for time series analysis such as fast Fourier transform (FFT). In this study, a new method for time series analysis with Bayesian information criterion was developed to decompose seiche, tide, long-term trend and residual components from time series data of tide stations. The method was developed based on the maximum marginal likelihood estimation of tide amplitudes, seiche amplitude, and trend components. Seiche amplitude and trend components were assumed that they gradually changes as second derivative in time was close to zero. These assumptions were incorporated as prior distributions. The variances of prior distributions were estimated by minimizing Akaike-Bayes information criterion (ABIC). The frequency of seiche was determined by Newton method with initial guess by FFT. The accuracy of proposed method was checked by analyzing synthetic time series data composed of known components. The reproducibility of the original components was quite well. The proposed method was also applied to the actual time series data of sea level observed by tide station and the strain of coastal rock masses observed by fiber Bragg grating sensor in Aburatsubo Bay, Japan. The seiche in bay and its response of rock masses were successfully extracted.

  1. Stereological estimation of the orbital volume: a criterion standard study.

    Science.gov (United States)

    Acer, Niyazi; Sahin, Bünyamin; Ergür, Hayati; Basaloglu, Hulki; Ceri, Nazli Gülriz

    2009-05-01

    Several methodologies have been proposed to assess the orbital volume (OV). However, we have not seen a criterion standard study evaluating the results of the methodologies for the assessment of OV. In the current study, the actual OV of 9 dry skulls was measured using the water filling method as the criterion standard. Consecutive computed tomographic sections at a thickness of 1.5 mm were used to estimate the OV by means of the point counting method. The mean (SD) of the OV measured by the water filling method was 17.84 (1.56) cm3. By using the point counting method, it was 17.05 (1.69) cm3. There was no statistically significant difference between sides (P > 0.001). The results of the OV values obtained by the two methods were compared statistically. The agreements between the two methods were also evaluated using the Bland-Altman plots. There was no statistically significant difference between the OV measurements obtained by the stereological technique and water filling method. The described method could be used for the assessment of OV in vivo.

  2. Job shop scheduling problem with late work criterion

    Science.gov (United States)

    Piroozfard, Hamed; Wong, Kuan Yew

    2015-05-01

    Scheduling is considered as a key task in many industries, such as project based scheduling, crew scheduling, flight scheduling, machine scheduling, etc. In the machine scheduling area, the job shop scheduling problems are considered to be important and highly complex, in which they are characterized as NP-hard. The job shop scheduling problems with late work criterion and non-preemptive jobs are addressed in this paper. Late work criterion is a fairly new objective function. It is a qualitative measure and concerns with late parts of the jobs, unlike classical objective functions that are quantitative measures. In this work, simulated annealing was presented to solve the scheduling problem. In addition, operation based representation was used to encode the solution, and a neighbourhood search structure was employed to search for the new solutions. The case studies are Lawrence instances that were taken from the Operations Research Library. Computational results of this probabilistic meta-heuristic algorithm were compared with a conventional genetic algorithm, and a conclusion was made based on the algorithm and problem.

  3. The kinetic origin of delayed yielding in metallic glasses

    Science.gov (United States)

    Ye, Y. F.; Liu, X. D.; Wang, S.; Fan, J.; Liu, C. T.; Yang, Y.

    2016-06-01

    Recent experiments showed that irreversible structural change or plasticity could occur in metallic glasses (MGs) even within the apparent elastic limit after a sufficiently long waiting time. To explain this phenomenon, a stochastic shear transformation model is developed based on a unified rate theory to predict delayed yielding in MGs, which is validated afterwards through extensive atomistic simulations carried out on different MGs. On a fundamental level, an analytic framework is established in this work that links time, stress, and temperature altogether into a general yielding criterion for MGs.

  4. 冬小麦节水高产的土壤水分阈值及其动态%Soil Water Threshold and its Dynamics of Winter Wheat Aiming Water-saving and High Yield

    Institute of Scientific and Technical Information of China (English)

    赵叶萌; 李玉中; 刘晓英; 钟秀丽; 曹金峰

    2015-01-01

    variation in soil water, was conducted in 2011/2012 at a site in Hengshui, Hebei Province. Relations between yield and soil water of different depth at seven growth stages were examined. Soil water threshold based on yield was explored and its dynamics was revealed. Results showed that the largest difference in soil water between the six deficient treatments and the well watered control occurred at shallow soil depth, and it decreased with deepening of soil layer. The difference was respectively 19.7%-36.5%, 9.3%-21.7% and 2.9%-9.7% at the soil layer of 0.4, 0.8 and 1.2m. In addition, variability of soil water decreased as soil depth increases. Relationship between grain yield of winter wheat and soil water of different depth at varying growth stages was parabolic functions of downward opening, but correlation significance changed with both growth stage and soil depth, being most significant for soil layer of 0. 4m. Soil water threshold based on yield diminished with progression of growth stages, from 83.1%-95% to 72.3%-90.0% of the field water capacity from jointing-booting to milk maturing at soil depth of 0.4, 0.6, 1.0, 1.2 and 1.6m. We recommended 0.4m being the most appropriate soil depth for detecting water deficit based on analysis in four aspects: difference in soil water dynamic and its average over the whole growing season between treatments, soil water variability at different soil depth, significance of the relations between soil water and yield at different growth stage. The corresponding water threshold at jointing-booting, heading, flowering, beginning-, middle -, later of grain filling and milk maturing was respectively 95.0%, 98.4%, 79.9%, 73.7%, 88.6%, 79.6% and 75.7%.

  5. A Comprehensive Theory of Yielding and Failure for Isotropic Materials

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, R M

    2006-08-10

    A theory of yielding and failure for homogeneous and isotropic materials is given. The theory is calibrated by two independent, measurable properties and from those it predicts possible failure for any given state of stress. It also differentiates between ductile yielding and brittle failure. The explicit ductile-brittle criterion depends not only upon the material specification through the two properties, but also and equally importantly depends upon the type of imposed stress state. The Mises criterion is a special (limiting) case of the present theory. A close examination of this case shows that the Mises material idealization does not necessarily imply ductile behavior under all conditions, only under most conditions. When the first invariant of the yield/failure stress state is sufficiently large relative to the distortional part, brittle failure will be expected to occur. For general material types, it is shown that it is possible to have a state of spreading plastic flow, but as the elastic-plastic boundary advances, the conditions for yielding on it can change over to conditions for brittle failure because of the evolving stress state. The general theory is of a three dimensional form and it applies to full density materials for which the yield/failure strength in uniaxial tension is less than or at most equal to the magnitude of that in uniaxial compression.

  6. Classification criterion of narrow/wide ice-resistant conical structures based on direct measurements

    Science.gov (United States)

    Xu, Ning; Yue, Qianjin; Yuan, Shuai; Liu, Xueqin; Shi, Wenqi

    2016-12-01

    Ice-induced structural vibration generally decreases with an increase in structural width at the waterline. Definitions of wide/narrow ice-resistant conical structures, according to ice-induced vibration, are directly related to structure width, sea ice parameters, and clearing modes of broken ice. This paper proposes three clearing modes for broken ice against conical structures: complete clearing, temporary ice pile up, and ice pile up. In this paper, sea ice clearing modes and the formation requirements of dynamic ice force are analyzed to explore criteria determining wide/narrow ice-resistant conical structures. According to the direct measurement data of typical prototype structures, primary quantitative criterion of the ratio of a cone width at waterline ( D) to sea ice thickness ( h) is proposed. If the ratio is less than 30 (narrow conical structure), broken ice is completely cleared and a dynamic ice force is produced; however, if the ratio is larger than 50 (wide conical structure), the front stacking of broken ice or dynamic ice force will not occur.

  7. YIELD OF AMARANTH

    African Journals Online (AJOL)

    department of Agricultural Engineering, University of Ibadan, Nigeria. (Received 28 ... properties, growth and shoot yield of large-green leafy amaranth (Amaranth sp.). Soil moisture ... microorganisms which stimulate the physical processes ... to plants and, consequently, crop establishment ... sustainable soil structure.

  8. 6 Grain Yield

    African Journals Online (AJOL)

    evaluate new interspecific genotypes for intensified double cropping of irrigated rice. The experimental ... the performance of the new irrigated .... nursing at a spacing of 20 cm between plants ..... if new technologies, comprising high yielding.

  9. Model Selection and Psychological Theory: A Discussion of the Differences between the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC)

    Science.gov (United States)

    Vrieze, Scott I.

    2012-01-01

    This article reviews the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) in model selection and the appraisal of psychological theory. The focus is on latent variable models, given their growing use in theory testing and construction. Theoretical statistical results in regression are discussed, and more important…

  10. A Reconsideration of the Extension Strain Criterion for Fracture and Failure of Rock

    Science.gov (United States)

    Wesseloo, J.; Stacey, T. R.

    2016-12-01

    The complex behaviours of rocks and rock masses have presented paradoxes to the rock engineer, including the fracturing of seemingly strong rock under low stress conditions, which often occurs near excavation boundaries. The extension strain criterion was presented as a fracture initiation criterion under these conditions (Stacey in Int J Rock Mech Min Sci 18:469-474, 1981). This criterion has been used successfully by some and criticised by others. In this paper, we review the literature on the extension strain criterion and present a case for the correct interpretation of the criterion and the conditions suitable for its use. We argue that the extension strain criterion can also be used to provide an indication of damage level under conditions of relatively low confining stress. We also present an augmentation of the criterion, the ultimate extension strain, which is applicable under extensional loading conditions when σ 2 is similar in magnitude to σ 1.

  11. R and G color component competition of RGB image decomposition as a criterion to register RBC agglutinates for blood group typing.

    Science.gov (United States)

    Doubrovski, Valeri A; Ganilova, Yuliya A; Zabenkov, Igor V

    2014-03-01

    A new approach of the criterion assignment for registration of erythrocyte agglutinates to instrumentally determine blood group type is suggested. The criterion is based on comparison of R and G components of RGB decomposition of microscopy digital image taken for the blood-serum mixture sample. For the chosen experimental conditions, the minimal size (area) of RBC agglutinate to be registered by the criterion suggested is estimated theoretically. The proposed method was tested experimentally on the example of monitoring agglutinates in flow. The encouraging experimental results were obtained for improvement of the resolving power of the method; the optimal experimental conditions were revealed for maximum resolution. Though the suggested method was realized for dynamic (flow) blood group determination, it could also be applied for diagnostics in a stationary environment. This approach increases the reliability of RBC agglutinates registration and, hence, blood group typing. The results may be used to develop the apparatus for automated determination of human blood group.

  12. Criterion Related Validity of Karate Specific Aerobic Test (KSAT)

    Science.gov (United States)

    Chaabene, Helmi; Hachana, Younes; Franchini, Emerson; Tabben, Montassar; Mkaouer, Bessem; Negra, Yassine; Hammami, Mehrez; Chamari, Karim

    2015-01-01

    Background: Karate is one the most popular combat sports in the world. Physical fitness assessment on a regular manner is important for monitoring the effectiveness of the training program and the readiness of karatekas to compete. Objectives: The aim of this research was to examine the criterion related to validity of the karate specific aerobic test (KSAT) as an indicator of aerobic level of karate practitioners. Patients and Methods: Cardiorespiratory responses, aerobic performance level through both treadmill laboratory test and YoYo intermittent recovery test level 1 (YoYoIRTL1) as well as time to exhaustion in the KSAT test (TE’KSAT) were determined in a total of fifteen healthy international karatekas (i.e. karate practitioners) (means ± SD: age: 22.2 ± 4.3 years; height: 176.4 ± 7.5 cm; body mass: 70.3 ± 9.7 kg and body fat: 13.2 ± 6%). Results: Peak heart rate obtained from KSAT represented ~99% of maximal heart rate registered during the treadmill test showing that KSAT imposes high physiological demands. There was no significant correlation between KSAT’s TE and relative (mL/min kg) treadmill maximal oxygen uptake (r = 0.14; P = 0.69; [small]). On the other hand, there was a significant relationship between KSAT’s TE and the velocity associated with VO2max (vVO2max) (r = 0.67; P = 0.03; [large]) as well as the velocity at VO2 corresponding to the second ventilatory threshold (vVO2 VAT) (r = 0.64; P = 0.04; [large]). Moreover, significant relationship was found between TE’s KSAT and both the total distance covered and parameters of intermittent endurance measured through YoYoIRTL1. Conclusions: The KSAT has not proved to have indirect criterion related validity as no significant correlations have been found between TE’s KSAT and treadmill VO2max. Nevertheless, as correlated to other aerobic fitness variables, KSAT can be considered as an indicator of karate specific endurance. The establishment of the criterion related validity of the KSAT

  13. Criterion Related Validity of Karate Specific Aerobic Test (KSAT

    Directory of Open Access Journals (Sweden)

    Chaabene

    2015-09-01

    Full Text Available Background Karate is one the most popular combat sports in the world. Physical fitness assessment on a regular manner is important for monitoring the effectiveness of the training program and the readiness of karatekas to compete. Objectives The aim of this research was to examine the criterion related to validity of the karate specific aerobic test (KSAT as an indicator of aerobic level of karate practitioners. Patients and Methods Cardiorespiratory responses, aerobic performance level through both treadmill laboratory test and YoYo intermittent recovery test level 1 (YoYoIRTL1 as well as time to exhaustion in the KSAT test (TE’KSAT were determined in a total of fifteen healthy international karatekas (i.e. karate practitioners (means ± SD: age: 22.2 ± 4.3 years; height: 176.4 ± 7.5 cm; body mass: 70.3 ± 9.7 kg and body fat: 13.2 ± 6%. Results Peak heart rate obtained from KSAT represented ~99% of maximal heart rate registered during the treadmill test showing that KSAT imposes high physiological demands. There was no significant correlation between KSAT’s TE and relative (mL/min kg treadmill maximal oxygen uptake (r = 0.14; P = 0.69; [small]. On the other hand, there was a significant relationship between KSAT’s TE and the velocity associated with VO2max (vVO2max (r = 0.67; P = 0.03; [large] as well as the velocity at VO2 corresponding to the second ventilatory threshold (vVO2 VAT (r = 0.64; P = 0.04; [large]. Moreover, significant relationship was found between TE’s KSAT and both the total distance covered and parameters of intermittent endurance measured through YoYoIRTL1. Conclusions The KSAT has not proved to have indirect criterion related validity as no significant correlations have been found between TE’s KSAT and treadmill VO2max. Nevertheless, as correlated to other aerobic fitness variables, KSAT can be considered as an indicator of karate specific endurance. The establishment of the criterion related validity of the

  14. Modeling soil water-salt dynamics and maize yield responses to groundwater depths and irrigations%土壤水盐与玉米产量对地下水埋深及灌溉响应模拟

    Institute of Scientific and Technical Information of China (English)

    郝远远; 徐旭; 黄权中; 黄冠华

    2014-01-01

    引黄水量的削减将进一步加剧宁夏银北灌区农业用水短缺问题,合理应用地下水进行灌溉对保障作物产量具有重要意义。为探究地下水灌溉条件下土壤水盐与作物生长的互馈机制,该研究修正了HYDRUS-1D的土壤蒸发模块,并嵌入可模拟作物生长与产量的 EPIC 模块,以此提高该模型在农田水文过程模拟中的适用性。采用2008年银北灌区不同水质灌水处理的玉米田间试验数据对模型进行了率定与验证。进一步应用该模型探寻地下水灌溉条件下,土壤水盐动态及玉米产量对地下水埋深变动及灌溉的响应规律。结果表明,玉米产量随地下水埋深增大呈现先增后减趋势,为保障玉米产量应将地下水适宜埋深控制在140~155 cm,且灌水量不宜低于现状灌水量,即玉米生育期内灌3水,每次900 m3/hm2。该研究对干旱银北灌区农业生产具有重要意义。%Reduction of water diversion from the Yellow River will intensify water shortage problems in the Yinbei Irrigation District (YID). Reasonable use of groundwater for irrigation is helpful to maintain the agricultural production. Groundwater exploitation may cause groundwater level declines in local areas. This helps to reduce the salinity accumulation in the root zone but decreases the capillary rise. Thus, it is important to figure out the responses of soil water-salt dynamics and crop yields to groundwater table fluctuations for salinity control and stable yields. In this study, HYDRUS-1D model was modified by coupling with the EPIC (erosion-productivity impact calculator) crop growth module for simulating agro-hydrological processes. The new crop module could simulate crop height, leaf area index (LAI), above-ground biomass and crop yield. The information between HYDRUS-1D and EPIC was exchanged by daily step. Root water uptake under water and salt stress was calculated with HYDRUS-1D and imported to EPIC to

  15. Preliminary Studies for Three Experiments at Treiman-Yang Criterion

    Science.gov (United States)

    Kres, I. V.; Kondratyev, V. N.; Cherubini, S.; Spitaleri, C.

    2016-05-01

    Nuclear reactions with three bodies in their final state may proceed through different reaction mechanisms. The Feynman graph technique has been widely used to describe such reactions. However, it is very difficult in general to select the graphs that dominate in given process. The Treiman-Yang criterion is one of the most powerful experimental tests for verifying the pole approximation prediction when describing a quasi-free reaction mechanism. We propose the theoretical study of the H2(B10, α Be7)ns, H1(B11, α1α2)αs, He3(Be9, α1α2)αs reactions at different energies. The preliminary study helps to check the existence of a QF channel by using the TY creterion.

  16. The alternative DSM-5 personality disorder traits criterion

    DEFF Research Database (Denmark)

    Bach, Bo; Maples-Keller, Jessica L; Bo, Sune

    2016-01-01

    The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; American Psychiatric Association, 2013a) offers an alternative model for Personality Disorders (PDs) in Section III, which consists in part of a pathological personality traits criterion measured...... with the Personality Inventory for DSM-5 (PID-5). The PID-5 selfreport instrument currently exists in the original 220-item form, a short 100-item form, and a brief 25-item form. For clinicians and researchers, the choice of a particular PID- 5 form depends on feasibility, but also reliability and validity. The goal...... of the present study was to examine the psychometric qualities of all 3 PID-5 forms, simultaneously, based on a Danish sample (N = 1376) of 451 psychiatric outpatients and 925 community-dwelling participants. Scale reliability and factorial validity were satisfactory across all 3 PID-5 forms. The correlational...

  17. Criterion and Incremental Validity of the Emotion Regulation Questionnaire

    Directory of Open Access Journals (Sweden)

    Christos A. Ioannidis

    2015-03-01

    Full Text Available Although research on emotion regulation (ER is developing, little attention has been paid to the predictive power of ER strategies beyond established constructs. The present study examined the incremental validity of the Emotion Regulation Questionnaire (ERQ; Gross & John, 2003, which measures cognitive reappraisal and expressive suppression, over and above the Big Five personality traits. It also extended the evidence for the measure’s criterion validity to yet unexamined criteria. A university student sample (N = 203 completed the ERQ, a measure of the Big Five, and relevant cognitive and emotion-laden criteria. Cognitive reappraisal predicted positive affect beyond personality, as well as experiential flexibility and constructive self-assertion beyond personality and affect. Expressive suppression explained incremental variance in negative affect beyond personality and in experiential flexibility beyond personality and general affect. No incremental effects were found for worry, social anxiety, rumination, reflection, and preventing negative emotions. Implications for the construct validity and utility of the ERQ are discussed.

  18. Bifurcation criterion of faults in complex nonlinear systems

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yagang, E-mail: yagangzhang@gmail.com [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing, 102206 (China); Department of Mathematics and Interdisciplinary Mathematics Institute, University of South Carolina, Columbia, SC 29208 (United States); Wang, Zengping [State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing, 102206 (China)

    2014-03-01

    In this paper, we introduce bifurcation theory into complex nonlinear systems. We adopt a novel approach to identify faults in electric circuit systems. After accidents occur without warning, with large numbers of complicated and high-precision calculations, we use bifurcation results of corresponding amplitude and frequency (period) to analyze their universal characteristics. Based on super attractive parameters, we have got the universal constant 4.6692… . The results from the present investigation imply that each fault in an electric circuit system must correspond to one or more bifurcation locations, which will provide a bifurcation criterion of faults in complex nonlinear systems. This research will have a significant theoretical value and engineering practical significance.

  19. Energy Criterion of Oil Film Failure during Friction

    Directory of Open Access Journals (Sweden)

    S.V. Fedorov

    2014-12-01

    Full Text Available The concepts developed by the thermodynamic theory of solid body strength and fracture are used to examine the conditions of lubricant film failure. We obtain a quantitative criterion that defines the lubricant film "defectness" - the critical value (constant for a given mineral oil of the internal (thermal energy density in the volume of the lubricant film. We propose analytic relations for evaluating scuffing in friction with lubrication and verify them experimentally on a full-scale stand for testing actual sliding bearings. We show the constancy of the critical value of the internal (thermal energy density in the volume of the oil film at the moment of scuffing for an inactive mineral oil.

  20. Metal-insulator transition: the Mott criterion and coherence length

    CERN Document Server

    Pergament, A

    2003-01-01

    On the basis of the Mott criterion for metal-insulator transition (MIT), an expression for the correlation length, identical to that for the coherence length in the theory of superconductivity, is obtained. This correlation length characterizes the size of an electron-hole pair (in an excitonic insulator) or the effective Bohr radius (as, e.g., in doped semiconductors). The relation obtained is used for calculation of the coherence length in vanadium dioxide. The presence of two characteristic coherence lengths (xi sub 1 approx 20 A and xi sub 2 approx 2 A) is found. This is associated with the specific features of the transition mechanism in VO sub 2 : this mechanism represents a combination of the purely electronic Mott-Hubbard contribution and the structural (Peierls-like) one. It is shown, however, that the driving force of the MIT in VO sub 2 is the electron-correlation Mott-Hubbard transition.

  1. A general Lipschitz uniqueness criterion for scalar ordinary differential equations

    Directory of Open Access Journals (Sweden)

    Josef Diblik

    2014-07-01

    Full Text Available The classical Lipschitz-type criteria guarantee unique solvability of the scalar initial value problem $\\dot x=f(t,x$, $x(t_0=x_0,$ by putting restrictions on $|f(t,x-f(t,y|$ in dependence of $|x-y|$. Geometrically it means that the field differences are estimated in the direction of the $x$-axis. In 1989, Stettner and the second author could establish a generalized Lipschitz condition in both arguments by showing that the field differences can be measured in a suitably chosen direction $v=(d_{t},d_{x}$, provided that it does not coincide with the directional vector $(1,f(t_{0},x_{0}$. Considering the vector $v$ depending on $t$, a new general uniqueness result is derived and a short proof based on the implicit function theorem is developed. The advantage of the new criterion is shown by an example. A comparison with known results is given as well.

  2. Criterion and incremental validity of the emotion regulation questionnaire.

    Science.gov (United States)

    Ioannidis, Christos A; Siegling, A B

    2015-01-01

    Although research on emotion regulation (ER) is developing, little attention has been paid to the predictive power of ER strategies beyond established constructs. The present study examined the incremental validity of the Emotion Regulation Questionnaire (ERQ; Gross and John, 2003), which measures cognitive reappraisal and expressive suppression, over and above the Big Five personality factors. It also extended the evidence for the measure's criterion validity to yet unexamined criteria. A university student sample (N = 203) completed the ERQ, a measure of the Big Five, and relevant cognitive and emotion-laden criteria. Cognitive reappraisal predicted positive affect beyond personality, as well as experiential flexibility and constructive self-assertion beyond personality and affect. Expressive suppression explained incremental variance in negative affect beyond personality and in experiential flexibility beyond personality and general affect. No incremental effects were found for worry, social anxiety, rumination, reflection, and preventing negative emotions. Implications for the construct validity and utility of the ERQ are discussed.

  3. QV modal distance displacement - a criterion for contingency ranking

    Energy Technology Data Exchange (ETDEWEB)

    Rios, M.A.; Sanchez, J.L.; Zapata, C.J. [Universidad de Los Andes (Colombia). Dept. of Electrical Engineering], Emails: mrios@uniandes.edu.co, josesan@uniandes.edu.co, cjzapata@utp.edu.co

    2009-07-01

    This paper proposes a new methodology using concepts of fast decoupled load flow, modal analysis and ranking of contingencies, where the impact of each contingency is measured hourly taking into account the influence of each contingency over the mathematical model of the system, i.e. the Jacobian Matrix. This method computes the displacement of the reduced Jacobian Matrix eigenvalues used in voltage stability analysis, as a criterion of contingency ranking, considering the fact that the lowest eigenvalue in the normal operation condition is not the same lowest eigenvalue in N-1 contingency condition. It is made using all branches in the system and specific branches according to the IBPF index. The test system used is the IEEE 118 nodes. (author)

  4. Biomechanical analysis of injury criterion for child and adult dummies.

    Science.gov (United States)

    Sances, A

    2000-01-01

    The development of human injury tolerance is difficult because of the physical differences between humans and animals, the available dummies, and tissue of the cadaver. Furthermore, human volunteer testing can clearly only be done at subinjurious levels. While considerable biomechanical injury evidence exists for the adult human based on cadaveric studies, little information is available for the pediatric population. However, some material is available from skull bone modulus studies and from the fetal tendon strength and early pediatric studies of the newborn. A review of living human, animal, and human cadaveric studies, which forms the basis for head-neck injury criterion are given. Examples of the use of the Hybrid III dummy for injury prediction such as in the Malibu rollover tests and air bag mechanisms show neck injury levels are considerably above the proposed Malibu 2000 N level.

  5. Validation of criterion-referenced archery cutting scores.

    Science.gov (United States)

    Ishee, J H; Titlow, L W

    1993-04-01

    This study investigated an empirical method for setting optimal cutting scores for a criterion-referenced archery test. The classification-outcome probabilities and approaches to validity suggested by Berk were utilized. Pretest scores were obtained on 35 uninstructed college-age women on six ends (six arrows each) from 20 yards (18.3 m) after an unrecorded warm-up end. Posttest scores were after 15 weeks of instruction. Score distributions were the primary determinant for accurately classifying students as true mastery and true nonmastery. Accuracy is a function of the amount of overlap between distributions. Using the point at which the distributions overlapped, classification accuracy was estimated. Probabilities associated with 80 points were p(TM) + p(TN) = .83 and p(FM) + p(FN) = .14. Scores above and below 80 points had lower probabilities of classification accuracy. Reliability estimated using Kappa was .59. Statistical validity of the cutting score (phi) was .68.

  6. New criterion of material resistance for brittle fracture

    Directory of Open Access Journals (Sweden)

    M. Maj

    2010-01-01

    Full Text Available Wide variety of cast material applications and efforts to find optimum fields for casting operation are the reasons why it is so important to collect as many data on the properties of materials as possible. The problem of primary importance is to know how these materials will behave under the normally and rapidly changing loads, in other words – to know their fatigue strength. This study gives a short characteristic of fatigue tests and compares various data collected during measurements of the low-cycle fatigue strength coefficient K with the values of constant KIc, representing fracture toughness. The results of the investigations described here have revealed some important correlations that exist between the total elongation A5 and the proposed brittleness criterion B, conventional stress K, and fracture toughness KIc. The development of measurements seems to be of great importance and opens the field for further studies on practical implementation of this method.

  7. Landau criterion for an anisotropic Bose-Einstein condensate

    Science.gov (United States)

    Yu, Zeng-Qiang

    2017-03-01

    In this work we discuss the Landau criterion for anisotropic superfluidity. To this end we consider a pointlike impurity moving in a uniform Bose-Einstein condensate with either interparticle dipole-dipole interaction or Raman-induced spin-orbit coupling. In both cases we find that the Landau critical velocity vc is generally smaller than the sound velocity in the moving direction. Beyond vc, the energy dissipation rate is explicitly calculated via a perturbation approach. In the plane-wave phase of a spin-orbit-coupled Bose gas, the dissipationless motion is suppressed by the Raman coupling even in the direction orthogonal to the recoil momentum. Our predictions can be tested in the experiments with ultracold atoms.

  8. SINGLE CRITERION SUPPLY CHAIN MANAGEMENT IN OLIVE OIL INDUSTRY

    Directory of Open Access Journals (Sweden)

    Silvija Vlah Jerić

    2010-12-01

    Full Text Available In this work we consider the supply chain management in olive oil industry. We construct the mixed-integer programming model connecting the optimization of olives harvesting and storage and olive oil production. The goal is to maximize the olive oil producer profit consisting of revenue, production cost and storage cost. In the same time, we have to take into the consideration the farmers’ (suppliers’ utility too. Namely, the suppliers want to maintain the harvest delay and delivery cost as minimal as possible. In the case of single criterion optimization problem we suppose that the producer is taking care of all five goals, so the objective function consists of the producer’s revenue, storage cost, production cost, harvest delay and delivery cost with the appropriate sign. Due to the big dimension of the problem two heuristics are proposed for solving it. Some simulations are performed and the results show good heuristics behavior.

  9. An Improved Ductile Fracture Criterion for Fine-blanking Process

    Institute of Scientific and Technical Information of China (English)

    ZHAO Zhen; ZHUANG Xin-cun; XIE Xiao-long

    2008-01-01

    In order to accurately simnulate the fine-blanking process,a suitable ductile fracture is significant.So an evaluation strategy based on experimental and corresponding simulation results of tensile,compression,torsion and fine-blanking test is designed to evaluate five typical ductile fracture criteria,which are widely-used in metal forming process.The stress triaxiality and ductile damage of each test specimen are analyzed.The results show that none of these five criteria is sufficient for all tests.Furthermore,an improved fracture criterion based on Rice and Tracey model,taking the influence of both volume change and shape change of voids into account,is proposed.The characterization of this model for fine-blanking process is easily done by the tensile test and the prediction result shows good.

  10. A criterion for lattice supersymmetry: cyclic Leibniz rule

    CERN Document Server

    Kato, Mitsuhiro; So, Hiroto

    2013-01-01

    It is old folklore that the violation of Leibniz rule on a lattice is an obstruction for constructing a lattice supersymmetric model. While it is still true for full supersymmetry, we show that a slightly modified form of the Leibniz rule, which we call cyclic Leibniz rule (CLR), is actually a criterion for the existence of partial lattice supersymmetry. In one dimension, we find sets of lattice difference operator and field multiplication smeared over lattice which satisfy the CLR under some natural assumptions such as translational invariance and locality. Thereby we construct a model of supersymmetric lattice quantum mechanics without spoiling locality. The CLR relation is coincident with the condition that the vanishing of the so-called surface term in the construction by lattice Nicolai map. We can construct superfield formalism with arbitrary superpotential. This also enables us to apply safely a localization technique to our model, because the kinetic term and the interaction terms of our model are ind...

  11. SME Support Programs in Europe: Granting and Evaluation criterion

    Directory of Open Access Journals (Sweden)

    Antonia Madrid Guijarro

    2005-02-01

    Full Text Available The aim of this paper is to analyze the situation of the support programs to SME in Europe. We identify the main support programs to this kind of firms and analyze the general criterion used to grant and evaluate these programs by the different agencies using a phone survey. Our sample is formed by 44 agencies included in EURADA which represent a coverage of 33,3%. The result show that the support program that will be increased in a higher number of agencies is the one related to "innovation and technological development", and the one that will be decreased in a higher number of agencies is the one related to "reestructuration of declining firms".

  12. Continuous control of chaos based on the stability criterion.

    Science.gov (United States)

    Yu, Hong Jie; Liu, Yan Zhu; Peng, Jian Hua

    2004-06-01

    A method of chaos control based on stability criterion is proposed in the present paper. This method can stabilize chaotic systems onto a desired periodic orbit by a small time-continuous perturbation nonlinear feedback. This method does not require linearization of the system around the stabilized orbit and only an approximate location of the desired periodic orbit is required which can be automatically detected in the control process. The control can be started at any moment by choosing appropriate perturbation restriction condition. It seems that more flexibility and convenience are the main advantages of this method. The discussions on control of attitude motion of a spacecraft, Rössler system, and two coupled Duffing oscillators are given as numerical examples.

  13. ADDED VALUE AS EFFICIENCY CRITERION FOR INDUSTRIAL PRODUCTION PROCESS

    Directory of Open Access Journals (Sweden)

    L. M. Korotkevich

    2016-01-01

    Full Text Available Literary analysis has shown that the majority of researchers are using classical efficiency criteria for construction of an optimization model for production process: profit maximization; cost minimization; maximization of commercial product output; minimization of back-log for product demand; minimization of total time consumption due to production change. The paper proposes to use an index of added value as an efficiency criterion because it combines economic and social interests of all main interested subjects of the business activity: national government, property owners, employees, investors. The following types of added value have been considered in the paper: joint-stock, market, monetary, economic, notional (gross, net, real. The paper makes suggestion to use an index of real value added as an efficiency criterion. Such approach permits to bring notional added value in comparable variant because added value can be increased not only due to efficiency improvement of enterprise activity but also due to environmental factors – excess in rate of export price increases over rate of import growth. An analysis of methods for calculation of real value added has been made on a country-by-country basis (extrapolation, simple and double deflation. A method of double deflation has been selected on the basis of the executed analysis and it is counted according to the Laspeyires, Paasche, Fischer indices. A conclusion has been made that the used expressions do not take into account fully economic peculiarities of the Republic of Belarus: they are considered as inappropriate in the case when product cost is differentiated according to marketing outlets; they do not take account of difference in rate of several currencies and such approach is reflected in export price of a released product and import price for raw material, supplies and component parts. Taking this into consideration expressions for calculation of real value added have been specified

  14. Decomposition Criterion-based Redundancy Removal in Mechanical Structures

    Directory of Open Access Journals (Sweden)

    A. N. Bozhko

    2014-01-01

    Full Text Available The most important design solutions of production engineering for the assembly operation are an assembly sequence and assembly chart. Both are closely linked with each other and therefore are recorded in the single process flow sheet that is an assembly chart.Capability for successive order assembling and splitting into assembly units depends on a set of the product design properties from which the main ones are position mechanical connections used to locate details within a product. An adequate mathematical model of the mechanical connections of technical system is a hyper graph. It allows us to give the correct description of the location relation of variable-locality.The analysis of the array of drawings shows that many designs contain redundant mechanical connections. The inequality is a criterion of redundancy, where |X| is the number of tops of the hyper graph (details, and |R| is the number of hyper edges (full assembly bases. Excess of mutual coordination is a harmful phenomenon which at designing stage exhibits as unsolvable dimension chains, while at the assembly stage it shows as relocation. Redundant connections should be removed from a design at the earliest design-for-manufacturing stages. Removal of connections generates mechanical structures with different assembly properties. The work offers some important criteria of generation of irredundant mechanical structures. The paper considers in detail a maximum decomposition criterion, which allows us to receive structures with the greatest capability to split into assembly units. It shows that such structures exhibit high flexibility in assembling and are adaptable to various specifications and production processes.

  15. PRINCIPLE OF PROPORTIONALITY, CRITERION OF LEGITIMACY IN THE PUBLIC LAW

    Directory of Open Access Journals (Sweden)

    MARIUS ANDREESCU

    2011-04-01

    Full Text Available A problem of essence of the state is the one to delimit the discretionary power, respectively the power abuse in the activity of the state’s institutions. The legal behavior of the state’s institutions consists in their right to appreciate them and the power excess generates the violation of a subjective right or of the right that is of legitimate interest to the citizen. The application and nonobservance of the principle of lawfulness in the activities of the state is a complex problem because the exercise of the state’s functions assumes the discretionary powers with which the states authorities are invested, or otherwise said the ‘right of appreciation” of the authorities regarding the moment of adopting the contents of the measures proposed. The discretionary power cannot be opposed to the principle of lawfulness, as a dimension of the state de jure. In this study we propose to analyze the concept of discretionary power, respectively the power excess, having as a guidance the legislation, jurisprudence and doctrine in the matter. At the same time we would like to identify the most important criterions that will allow the user, regardless that he is or not an administrator, a public clerk or a judge, to delimit the legal behavior of the state’s institutions from the power excess. Within this context, we appreciate that the principle of proportionality represents such a criterion. The proportionality is a legal principle of the law, but at the same time it is a principle of the constitutional law and of other law branches. It expresses clearly the idea of balance, reasonability but also of adjusting the measures ordered by the state’s authorities to the situation in fact, respectively to the purpose for which they have been conceived. In our study we choose theoretical and jurisprudence arguments according to which the principle of proportionality can procedurally be determined and used to delimit the discretionary power and

  16. PRINCIPLE OF PROPORTIONALITY, CRITERION OF LEGITIMACY IN THE PUBLIC LAW

    Directory of Open Access Journals (Sweden)

    Marius ANDREESCU

    2011-08-01

    Full Text Available A problem of essence of the state is the one to delimit the discretionary power, respectively the power abuse in the activity of the state’s institutions. The legal behavior of the state’s institutions consists in their right to appreciate them and the power excess generates the violation of a subjective right or of the right that is of legitimate interest to the citizen. The application and nonobservance of the principle of lawfulness in the activities of the state is a complex problem because the exercise of the state’s functions assumes the discretionary powers with which the states authorities are invested, or otherwise said the ‘right of appreciation” of the authorities regarding the moment of adopting the contents of the measures proposed. The discretionary power cannot be opposed to the principle of lawfulness, as a dimension of the state de jure. In this study we propose to analyze the concept of discretionary power, respectively the power excess, having as a guidance the legislation, jurisprudence and doctrine in the matter. At the same time we would like to identify the most important criterions that will allow the user, regardless that he is or not an administrator, a public clerk or a judge, to delimit the legal behavior of the state’s institutions from the power excess. Within this context, we appreciate that the principle of proportionality represents such a criterion. The proportionality is a legal principle of the law, but at the same time it is a principle of the constitutional law and of other law branches. It expresses clearly the idea of balance, reasonability but also of adjusting the measures ordered by the state’s authorities to the situation in fact, respectively to the purpose for which they have been conceived. In our study we choose theoretical and jurisprudence arguments according to which the principle of proportionality can procedurally be determined and used to delimit the discretionary power and

  17. Continuous-Time Portfolio Selection and Option Pricing under Risk-Minimization Criterion in an Incomplete Market

    Directory of Open Access Journals (Sweden)

    Xinfeng Ruan

    2013-01-01

    Full Text Available We study option pricing with risk-minimization criterion in an incomplete market where the dynamics of the risky underlying asset are governed by a jump diffusion equation. We obtain the Radon-Nikodym derivative in the minimal martingale measure and a partial integrodifferential equation (PIDE of European call option. In a special case, we get the exact solution for European call option by Fourier transformation methods. Finally, we employ the pricing kernel to calculate the optimal portfolio selection by martingale methods.

  18. Blasting Vibration Safety Criterion Analysis with Equivalent Elastic Boundary: Based on Accurate Loading Model

    Directory of Open Access Journals (Sweden)

    Qingwen Li

    2015-01-01

    Full Text Available In the tunnel and underground space engineering, the blasting wave will attenuate from shock wave to stress wave to elastic seismic wave in the host rock. Also, the host rock will form crushed zone, fractured zone, and elastic seismic zone under the blasting loading and waves. In this paper, an accurate mathematical dynamic loading model was built. And the crushed zone as well as fractured zone was considered as the blasting vibration source thus deducting the partial energy for cutting host rock. So this complicated dynamic problem of segmented differential blasting was regarded as an equivalent elastic boundary problem by taking advantage of Saint-Venant’s Theorem. At last, a 3D model in finite element software FLAC3D accepted the constitutive parameters, uniformly distributed mutative loading, and the cylindrical attenuation law to predict the velocity curves and effective tensile curves for calculating safety criterion formulas of surrounding rock and tunnel liner after verifying well with the in situ monitoring data.

  19. Yield and Solidification of Yield-Stress Materials in Rigid Networks and Porous Structures

    CERN Document Server

    Sochi, Taha

    2013-01-01

    In this paper, we address the issue of threshold yield pressure of yield-stress materials in rigid networks of interconnected conduits and porous structures subject to a pressure gradient. We compare the results as obtained dynamically from solving the pressure field to those obtained statically from tracing the path of the minimum sum of threshold yield pressures of the individual conduits by using the threshold path algorithms. We refute criticisms directed recently to our previous findings that the pressure field solution generally produces a higher threshold yield pressure than the one obtained by the threshold path algorithms. Issues related to the solidification of yield stress materials in their transition from fluid phase to solid state have also been investigated and assessed as part of the investigation of the yield point.

  20. Crop yields in intercropping

    NARCIS (Netherlands)

    Yu, Y.

    2016-01-01

    Abstract

    Intercropping, the cultivation of two or more crop species simultaneously in the same field, has been widely practiced by smallholder farmers in developing countries and is gaining increasing interest in developed countries. Intercropping can increase the yield per

  1. Crop yields in intercropping

    NARCIS (Netherlands)

    Yu, Y.

    2016-01-01

    Abstract

    Intercropping, the cultivation of two or more crop species simultaneously in the same field, has been widely practiced by smallholder farmers in developing countries and is gaining increasing interest in developed countries. Intercropping can increase the yield per

  2. An optimality criterion for sizing members of heated structures with temperature constraints. [considering aerospace structures

    Science.gov (United States)

    Rao, G. V.; Shore, C. P.; Narayanaswami, R.

    1977-01-01

    A thermal optimality criterion is presented for sizing members of heated structures with multiple temperature constraints. The optimality criterion is similar to an existing optimality criterion for design of mechanically loaded structures with displacement constraints. Effectiveness of the thermal optimality criterion is assessed by applying it to one- and two-dimensional thermal problems where temperatures can be controlled by varying the material distribution in the structure. Results obtained from the optimality criterion agree within 2 percent with results from a closed-form solution and with results from a mathematical programming technique. The thermal optimality criterion augments existing optimality criteria for strength and stiffness related constraints and offers the possibility of extension of optimality techniques to sizing structures with combined thermal and mechanical loading.

  3. Validation of a Criterion for Cam Mechanisms Optimization Using Constraints upon Cam’s Curvature

    Directory of Open Access Journals (Sweden)

    Stelian Alaci

    2016-06-01

    Full Text Available For the mechanism with rotating cam and knife-edge follower, an optimization criterion by means of imposed constraints upon cam’s curvature is expressed in a special coordinate system. Thus, stating the optimization criterion in the coordinate system defined by the mechanisms constructive parameters -eccentricity and minimum follower’s stroke, a contour is obtained for any position of the mechanism. The optimization criterion assumes establishing the position of the characteristic point of the mechanism with respect to this contour. Fulfillment of optimization criterion assumes that the characteristic point is positioned in the same manner with respect to all contours. The optimization criterion is simplified when considering the envelope of the contours. The method is exemplified using two mechanisms, with the cams priori satisfying the criterion.

  4. Validation of Hoek-Brown failure criterion charts for rock slopes

    Institute of Scientific and Technical Information of China (English)

    A.M. Nekouei; K. Ahangari

    2013-01-01

    Although stability charts suggested by Hoek and Bray on the basis of Mohr-Coulomb criterion are used for rock slopes, but complete and precise recognition is required for distinguishing cohesive strength and Mohr-Coulomb equivalent internal friction angle for rock mass. The paper by Lia et al. [6] is the only one that introduced rock slope charts according to Hoek-Brown failure criterion. In this paper, at first, this type of charts is introduced. Then, Mohr-Coulomb failure criterion charts [2] are compared and validated with Hoek-Brown failure criterion ones [6]. Next, Bishop method utilizing Slide software is compared with Hoek-Brown failure criterion stability charts. Average standard deviation (ASD), root mean square error (RMSE) and variance account for (VAF) were used for the comparison. According to the results, because of high distribution and very low correlation among the comparisons, Hoek-Brown failure crite-rion charts are not efficient.

  5. Simulation of oil palm growth and yield.

    NARCIS (Netherlands)

    Kraalingen, van D.W.G.; Breure, C.J.; Spitters, C.J.T.

    1989-01-01

    A dynamic model is presented to simulate growth and yield formation of oil palm (Elaeis quineensis Jacq.) in dependence of weather data and plant characteristics. From incoming amounts of light, light interception of the foliage and photosynthetic characteristics of individual leaflets, daily rates

  6. Simulation of oil palm growth and yield.

    NARCIS (Netherlands)

    Kraalingen, van D.W.G.; Breure, C.J.; Spitters, C.J.T.

    1989-01-01

    A dynamic model is presented to simulate growth and yield formation of oil palm (Elaeis quineensis Jacq.) in dependence of weather data and plant characteristics. From incoming amounts of light, light interception of the foliage and photosynthetic characteristics of individual leaflets, daily rates

  7. Modulus and yield stress of drawn LDPE

    Science.gov (United States)

    Thavarungkul, Nandh

    Modulus and yield stress were investigated in drawn low density polyethylene (LDPE) film. Uniaxially drawn polymeric films usually show high values of modulus and yield stress, however, studies have normally only been conducted to identify the structural features that determine modulus. In this study small-angle x-ray scattering (SAXS), thermal shrinkage, birefringence, differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA) were used to examine, directly and indirectly, the structural features that determine both modulus and yield stress, which are often closely related in undrawn materials. Shish-kebab structures are proposed to account for the mechanical properties in drawn LDPE. The validity of this molecular/morphological model was tested using relationships between static mechanical data and structural and physical parameters. In addition, dynamic mechanical results are also in line with static data in supporting the model. In the machine direction (MD), "shish" and taut tie molecules (TTM) anchored in the crystalline phase account for E; whereas crystal lamellae with contributions from "shish" and TTM determine yield stress. In the transverse direction (TD), the crystalline phase plays an important roll in both modulus and yield stress. Modulus is determined by crystal lamellae functioning as platelet reinforcing elements in the amorphous matrix with an additional contributions from TTM and yield stress is determined by the crystal lamellae's resistance to deformation.

  8. [A new method of identifying a systems based on the minimal quadratic discrepancy criterion for biophysics problems].

    Science.gov (United States)

    Karnaukhov, A V; Karnaukhova, E V

    2004-01-01

    A wide range of biophysical systems are described by nonlinear dynamic models mathematically presented as a set of ordinary differential equations in the Cauchy explicit form: [formula: see text] Fij(X1(t),..,XN(t),t), (i = 1,...,N, j = 1,...,M), where Fij (X1(t), ..., XN(t), t) is a set of basis functions satisfying the Lipschitz condition. We investigate the problem of evaluation of model constants aij (the system identification) using experimental data about the time dependence of the dynamic parameters of the system Xi(t). A new method of system identification for the class of similar nonlinear dynamic models is proposed. It is shown that the problem of identifying an initial nonlinear model can be reduced to the solution of a system of linear equations for the matrix of the dynamic model constants [aj]i. It is proposed to determine the set of dynamic model constants aij using the criterion of minimal quadratic discrepancy for the time dependence of the set of dynamic parameters Xi(t). An important special case of the nonlinear model, the quadratic model, is considered. Test problems of identification using this method are presented for two nonlinear systems: the Van der Pol type multiparametric nonlinear oscillator and the strange attractor of Ressler, a widely known example of dynamic systems showing the stochastic behavior.

  9. The Criterion A problem revisited: controversies and challenges in defining and measuring psychological trauma.

    Science.gov (United States)

    Weathers, Frank W; Keane, Terence M

    2007-04-01

    The Criterion A problem in the field of traumatic stress refers to the stressor criterion for posttraumatic stress disorder (PTSD) and involves a number of fundamental issues regarding the definition and measurement of psychological trauma. These issues first emerged with the introduction of PTSD as a diagnostic category in the Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III; American Psychiatric Association, 1980) and continue to generate considerable controversy. In this article, the authors provide an update on the Criterion A problem, with particular emphasis on the evolution of the DSM definition of the stressor criterion and the ongoing debate regarding broad versus narrow conceptualizations of traumatic events.

  10. A Criterion for Maximally Six-Qubit Entangled States via Coefficient Matrix

    Science.gov (United States)

    Yu, Yan; Zha, Xin Wei; Li, Wei

    2017-03-01

    In a recent paper (J. Phys. A: Math. Theor 45, 075308 (2012)), Li et al. established the coefficient matrix of six-qubit entangled states. With an emphasis on six qubits, we present a new criterion for maximally six-qubit entangled states via those coefficient matrices. By calculating the determinants of coefficient matrix, one use the criterion that characterize these states. Moreover, the criterion via the coefficient matrices gives rise to the combination of maximally multi-qubit entangled state(MMES) and matrix, and we believe that the new criterion can play an important role in quantum information.

  11. Applicability and generality of the modified Grübler-Kutzbach criterion

    Science.gov (United States)

    Li, Yanwen; Wang, Lumin; Liu, Jingfang; Huang, Zhen

    2013-03-01

    A generally applicable criterion for all mechanism mobility has been an active domain in mechanism theory lasting more than 150 years. It is stated that the Modified Grübler-Kutzbach criterion for mobility has been successfully used to solve the mobility of many more kinds of mechanisms, but never before has anyone proven the applicability and generality of the Modified Grübler-Kutzbach criterion in theory. In order to fill the gap, the applicability and generality of the Modified Grübler-Kutzbach Criterion of mechanism mobility is systematically demonstrated. Firstly, the mobility research background and the Modified Grübler-Kutzbach criterion are introduced. Secondly, some new definitions, such as half local freedom, non-common constraint space of a mechanism and common motion space of a mechanism, etc, are given to demonstrate the correctness and broad applicability of the Modified Grübler-Kutzbach criterion. Thirdly, the general applicability of the Modified Grübler-Kutzbach criterion is demonstrated based on screw theory. The mobilities of the classical DELASSUS mechanisms and a modern planar parallel mechanism, are determined through the Modified Grübler-Kutzbach criterion, which are as examples to show the practical application of the Modified Grübler-Kutzbach criterion.

  12. Couplings in Multi-criterion Aerodynamic Optimization Problems Using Adjoint Methods and Game Strategies

    Institute of Scientific and Technical Information of China (English)

    Tang Zhili; Dong Jun

    2009-01-01

    complete and complete decisions of the leader and followers respectively. Several design examples illustrate the efficiency of the coupling algorithms for multi-criterion aerodynamic design optimization problems.

  13. Nonlinear viscoelasticity and generalized failure criterion for biopolymer gels

    Science.gov (United States)

    Divoux, Thibaut; Keshavarz, Bavand; Manneville, Sébastien; McKinley, Gareth

    2016-11-01

    Biopolymer gels display a multiscale microstructure that is responsible for their solid-like properties. Upon external deformation, these soft viscoelastic solids exhibit a generic nonlinear mechanical response characterized by pronounced stress- or strain-stiffening prior to irreversible damage and failure, most often through macroscopic fractures. Here we show on a model acid-induced protein gel that the nonlinear viscoelastic properties of the gel can be described in terms of a 'damping function' which predicts the gel mechanical response quantitatively up to the onset of macroscopic failure. Using a nonlinear integral constitutive equation built upon the experimentally-measured damping function in conjunction with power-law linear viscoelastic response, we derive the form of the stress growth in the gel following the start up of steady shear. We also couple the shear stress response with Bailey's durability criteria for brittle solids in order to predict the critical values of the stress σc and strain γc for failure of the gel, and how they scale with the applied shear rate. This provides a generalized failure criterion for biopolymer gels in a range of different deformation histories. This work was funded by the MIT-France seed fund and by the CNRS PICS-USA scheme (#36939). BK acknowledges financial support from Axalta Coating Systems.

  14. Fluency: an aim in teaching and a criterion in assessment

    Directory of Open Access Journals (Sweden)

    Aud Marit Simensen

    2010-05-01

    Full Text Available This article investigates the concept ‘fluency’ from different perspectives. When fluency is an aim in teaching, a thorough comprehension of the concept among teachers is a prerequisite for appropriate planning of instruction, including the choice of appropriate classroom activities. When fluency is an assessment criterion, it is even more important that examiners have a shared perception of the concept. The present article starts by presenting common perceptions of the concept and goes on to explore some of the current research. Next, it provides a historical overview of the place of fluency in teaching theory and explains some of the preconditions for the inclusion of this concept among teaching objectives and assessment criteria. It will also, as an illustration, give an outline of the position of the concept over time in the Norwegian school system on the basis of an analysis of the relevant syllabuses. Finally, the article explicates the notion of language use as a complex cognitive skill and explores current method¬ological ideas about teaching towards fluency.

  15. The effects of criterion variability on relative operating characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Brown, W.S. [Brookhaven Natl. Lab., Bldg. 130, Upton, NY 11973-5000 (United States); Emmerich, D.S. [State Univ. of New York at Stony Brook, Stony Brook, NY 11974 (United States)

    1995-05-01

    The form of the relative operating characteristic (ROC) describing auditory detection typically differs from that expected based on the assumption that the observer`s responses reflect underlying distributions that are normal and of equal variance [e.g., Green and Swets, {ital Signal} {ital Detection} {ital Theory} {ital and} {ital Psychophysics}]. Specifically, it is found that binormal ROCs often have slopes less than one, and are not strictly linear [Watson {ital et} {ital al}., 283--288 (1964)]. It has been suggested that nonlinear binormal ROCs may be the result of extreme criteria being more variable than those more centrally positioned [Emmerich and Binder, J. Acoust. Soc. Am. Suppl. 1 {bold 65}, S59 (1979)]. The forms of rating ROCs obtained in an experiment designed to reveal the effects of such variability were consistent with the proposition that criteria associated with ``no`` responses are more variable than those associated with ``yes`` responses. Criterion operating characteristics [Wickelgren, J. Math. Psychol. {bold 5}, 102--122], which reflect the relative locations and variances of the boundaries of confidence categories, favored the same interpretation. It is concluded that the variability of criteria defining categories of rated confidence is sizable and not necessarily constant across criteria, and that such variability significantly influences the forms of empirical ROCs determined using confidence ratings in auditory signal detection.

  16. Centration-distortion error: a criterion of perceptual dysfunction.

    Science.gov (United States)

    Mecke, V

    This was a study to determine whether centration, as a perceptual process, could be a criterion for differentiating between neurologically impaired and emotionally disturbed children. Centration was defined by Piaget as a prolonged involuntary attachment of a sensory modality to one part of a field, causing perceptual errors of exaggerations and distortions. It is hypothesized that centration would affect motor behavior, producing effects on drawing tasks characterized by separation of designs or their parts, coincident with distortions of the figures drawn. The neurologically impaired children were identified as having primary difficulties with perception whereas the emotionally disturbed children would have primary difficulties with intellection. The centration-distortion error would characterize the drawing of the neurologically impaired but not those of the emotionally disturbed children. A sample of 44 children was selected, each with EEG records, psychological tests and psychiatric interviews used as differential criteria for the groups. Eleven children were diagnosed as having minimal brain damage, 33 as emotionally disturbed. Three psychologists scored the Bender Gestalt tests, blind, for indicators of brain injury and emotional disturbance as defined by Koppitz' criteria, and for the centration-distortion error. The hypothesis was upheld at the .001 level of confidence, validating an earlier pilot study.

  17. Development of a wrinkled pipeline fatigue ultimate limit state criterion

    Energy Technology Data Exchange (ETDEWEB)

    Semiga, V.; Tiku, S.; Dinovitzer, A. [BMT Fleet Technology Ltd., Kanata (Canada); Zhou, J.; Sen, M. [TransCanada PipeLines Ltd., Calgary, AB (Canada)

    2009-07-01

    This paper described research currently being conducted to develop a mechanics-based wrinkle ultimate limit state for evaluating the long-term integrity of wrinkled pipeline segments. Efforts included testing and non-linear finite element analysis (FEA) of small-scale and full-scale wrinkled pipeline segments. The aim of the program was to develop a set of monotonic and cyclic material properties for use in designing a failure assessment procedure. A failure criterion has also been developed to predict the fatigue life of experimental pipeline specimens. An experimental material properties database was developed for several pipeline materials ranging from API grade X60 to X100 steel pipelines. Multiple monotonic tensile tests were conducted for all materials used in the program. Experimental stress-strain curves were used to develop finite element material models during the modelling phase of the project. Complete strain life curves were also obtained. A small scale strip test was developed to predict the fatigue life of strip test specimens. Nonlinear kinematic material models were also developed. Results of the program to date indicate that the finite element method (FEM) model is capable of accurately estimating the cyclic fatigue life of pipelines with wrinkles. It was concluded that the FEM model will also be used to examine the interactions between soil and buried pipelines. 6 refs., 14 figs.

  18. Wang-Landau sampling: a criterion for halting the simulations.

    Science.gov (United States)

    Caparica, A A

    2014-04-01

    In this work we propose a criterion to finish the simulations of the Wang-Landau sampling. Instead of determining a final modification factor for all simulations and every sample size, we investigate the behavior of the temperature of the peak of the specific heat during the simulations and finish them when this value varies below a given limit. As a result, different runs stop at different final modification factors. We show that in place of the temperature of the peak of the specific heat one can adopt alternatively the integrated heat transfer as a reference quantity. We apply this technique to the two-dimensional Ising model and a homopolymer. We verify that for the Ising model the mean order of the final modification factors is roughly the same for all lattice sizes, but for the homopolymer the order of the final modification factors increases with increasing polymer sizes. The results show that the simulations can be halted much earlier than is conventional in Wang-Landau sampling, but manifold finite-size simulations are required in order to obtain accurate results. A brief application to the three-dimensional Ising model is also available.

  19. Jeans instability criterion modified by external tidal field

    CERN Document Server

    Jog, Chanda J

    2013-01-01

    The well-known Jeans criterion describes the onset of instabilities in an infinite, homogeneous, self-gravitating medium supported by pressure. Most realistic astrophysical systems, however, are not isolated - instead they are under the influence of an external field such as the tidal field due to a neighbour. Here we do a linear perturbation analysis for a system in an external field, and obtain a generalized dispersion relation that depends on the wavenumber, the sound speed, and also the magnitude of the tidal field. A typical, disruptive tidal field is shown to make the system more stable against perturbations, and results in a higher effective Jeans wavelength. The minimum mass that can become unstable is then higher (super-Jeans) than the usual Jeans mass. Conversely, in a compressive tidal field, perturbations can grow even when the mass is lower (sub-Jeans). This approach involving the inclusion of tidal field opens up a new way of looking at instabilities in gravitating systems. The treatment is gene...

  20. Creep Analysis of a Variable Thickness Rotating FGM Disc using Tresca Criterion

    Directory of Open Access Journals (Sweden)

    Kishore Khanna

    2015-04-01

    Full Text Available The study investigates steady-state creep in a rotating Al-SiCp disc having different thickness profiles and reinforcement (SiCp gradients. The disc material is assumed to creep according to threshold-stress based law and yield following Tresca criterion. The stresses and strain rates in the disc are estimated by solving the disc equilibrium equation along with creep constitutive equations. It was observed that on increasing the disc thickness gradient, the radial stress decreases towards the inner radius but increases towards the outer radius, whereas the tangential stress decreases over the entire radius. With the increase in SiCp gradient in the FGM disc, the radial stress increases significantly throughout, however, the tangential stress increases towards the inner radius but decreases towards the outer radius. The strain rates in the disc reduce significantly over the entire disc radius and become relatively uniform with the increase in either disc thickness gradient or reinforcement gradient. Thus, the composite disc having higher thickness and higher reinforcement gradients exhibits lesser distortion.Defence Science Journal, Vol. 65, No. 2, March 2015, pp.163-170, DOI:http://dx.doi.org/10.14429/dsj.65.8045

  1. Dynamical renormalization group resummation of finite temperature infrared divergences

    CERN Document Server

    Boyanovsky, D; Holman, R; Simionato, M

    1999-01-01

    We introduce the method of dynamical renormalization group to study relaxation and damping out of equilibrium directly in real time and applied it to the study of infrared divergences in scalar QED. This method allows a consistent resummation of infrared effects associated with the exchange of quasistatic transverse photons and leads to anomalous logarithmic relaxation of the form $e^{-\\alpha T t \\ln[t/t_0]}$ which prevents a quasiparticle interpretation of charged collective excitations at finite temperature. The hard thermal loop resummation program is incorporated consistently into the dynamical renormalization group yielding a picture of relaxation and damping phenomena in a plasma in real time that trascends the conceptual limitations of the quasiparticle picture and other type of resummation schemes. We derive a simple criterion for establishing the validity of the quasiparticle picture to lowest order.

  2. Estimating Corporate Yield Curves

    OpenAIRE

    Antionio Diaz; Frank Skinner

    2001-01-01

    This paper represents the first study of retail deposit spreads of UK financial institutions using stochastic interest rate modelling and the market comparable approach. By replicating quoted fixed deposit rates using the Black Derman and Toy (1990) stochastic interest rate model, we find that the spread between fixed and variable rates of interest can be modeled (and priced) using an interest rate swap analogy. We also find that we can estimate an individual bank deposit yield curve as a spr...

  3. Economic feasibility of reequipment terms based on profitability criterion

    National Research Council Canada - National Science Library

    D.V. Bezugla

    2015-01-01

    The aim of the article. The aim of the research is to improve the methodological approaches to a priori determining the initial indices of profitability of technological equipment to solve the dynamic optimization task over...

  4. Crop Yield Forecasted Model Based on Time Series Techniques

    Institute of Scientific and Technical Information of China (English)

    Li Hong-ying; Hou Yan-lin; Zhou Yong-juan; Zhao Hui-ming

    2012-01-01

    Traditional studies on potential yield mainly referred to attainable yield: the maximum yield which could be reached by a crop in a given environment. The new concept of crop yield under average climate conditions was defined in this paper, which was affected by advancement of science and technology. Based on the new concept of crop yield, the time series techniques relying on past yield data was employed to set up a forecasting model. The model was tested by using average grain yields of Liaoning Province in China from 1949 to 2005. The testing combined dynamic n-choosing and micro tendency rectification, and an average forecasting error was 1.24%. In the trend line of yield change, and then a yield turning point might occur, in which case the inflexion model was used to solve the problem of yield turn point.

  5. Climate Change and Maize Yield in Iowa.

    Science.gov (United States)

    Xu, Hong; Twine, Tracy E; Girvetz, Evan

    2016-01-01

    Climate is changing across the world, including the major maize-growing state of Iowa in the USA. To maintain crop yields, farmers will need a suite of adaptation strategies, and choice of strategy will depend on how the local to regional climate is expected to change. Here we predict how maize yield might change through the 21st century as compared with late 20th century yields across Iowa, USA, a region representing ideal climate and soils for maize production that contributes substantially to the global maize economy. To account for climate model uncertainty, we drive a dynamic ecosystem model with output from six climate models and two future climate forcing scenarios. Despite a wide range in the predicted amount of warming and change to summer precipitation, all simulations predict a decrease in maize yields from late 20th century to middle and late 21st century ranging from 15% to 50%. Linear regression of all models predicts a 6% state-averaged yield decrease for every 1°C increase in warm season average air temperature. When the influence of moisture stress on crop growth is removed from the model, yield decreases either remain the same or are reduced, depending on predicted changes in warm season precipitation. Our results suggest that even if maize were to receive all the water it needed, under the strongest climate forcing scenario yields will decline by 10-20% by the end of the 21st century.

  6. A Topological Criterion for Filtering Information in Complex Brain Networks

    Science.gov (United States)

    Latora, Vito; Chavez, Mario

    2017-01-01

    In many biological systems, the network of interactions between the elements can only be inferred from experimental measurements. In neuroscience, non-invasive imaging tools are extensively used to derive either structural or functional brain networks in-vivo. As a result of the inference process, we obtain a matrix of values corresponding to a fully connected and weighted network. To turn this into a useful sparse network, thresholding is typically adopted to cancel a percentage of the weakest connections. The structural properties of the resulting network depend on how much of the inferred connectivity is eventually retained. However, how to objectively fix this threshold is still an open issue. We introduce a criterion, the efficiency cost optimization (ECO), to select a threshold based on the optimization of the trade-off between the efficiency of a network and its wiring cost. We prove analytically and we confirm through numerical simulations that the connection density maximizing this trade-off emphasizes the intrinsic properties of a given network, while preserving its sparsity. Moreover, this density threshold can be determined a-priori, since the number of connections to filter only depends on the network size according to a power-law. We validate this result on several brain networks, from micro- to macro-scales, obtained with different imaging modalities. Finally, we test the potential of ECO in discriminating brain states with respect to alternative filtering methods. ECO advances our ability to analyze and compare biological networks, inferred from experimental data, in a fast and principled way. PMID:28076353

  7. Criterion-based (proficiency) training to improve surgical performance.

    Science.gov (United States)

    Fried, Marvin P; Kaye, Rachel J; Gibber, Marc J; Jackman, Alexis H; Paskhover, Boris P; Sadoughi, Babak; Schiff, Bradley; Fraioli, Rebecca E; Jacobs, Joseph B

    2012-11-01

    OBJECTIVE To investigate whether training otorhinolaryngology residents to criterion performance levels (proficiency) on the Endoscopic Sinus Surgery Simulator produces individuals whose performance in the operating room is at least equal to those who are trained by performing a fixed number of surgical procedures. DESIGN Prospective cohort. SETTING Two academic medical centers in New York City. PARTICIPANTS Otorhinolaryngology junior residents composed of 8 experimental subjects and 6 control subjects and 6 attending surgeons. INTERVENTION Experimental subjects achieved benchmark proficiency criteria on the Endoscopic Sinus Surgery Simulator; control subjects repeated the surgical procedure twice. MAIN OUTCOME MEASURES Residents completed validated objective tests to assess baseline abilities. All subjects were videotaped performing an initial standardized surgical procedure. Residents were videotaped performing a final surgery. Videotapes were assessed for metrics by an expert panel. RESULTS Attendings outperformed the residents in most parameters on the initial procedure. Experimental and attending groups outperformed controls in some parameters on the final procedure. There was no difference between resident groups in initial performance, but the experimental subjects outperformed the control subjects in navigation in the final procedure. Most important, there was no difference in final performance between subgroups of the experimental group on the basis of the number of trials needed to attain proficiency. CONCLUSIONS Simulator training can improve resident technical skills so that each individual attains a proficiency level, despite the existence of an intrinsic range of abilities. This proficiency level translates to at least equal, if not superior, operative performance compared with that of current conventional training with finite repetition of live surgical procedures.

  8. BOUNDEDNESS CRITERION FOR SOME COMMUTATORS OF LINEAR OPERATORS

    Institute of Scientific and Technical Information of China (English)

    Chen Wengu; Hu Guoen

    2001-01-01

    The paper is to establish a boundedness criterion for somecommutators of linear operators when these linear operators don't satisfy the general Ap weight estimates but satisfy some radial weight estimates. CLC Number:O17 Document ID:AFoundation Item:The paper was partly supported by National Natural Science Foundation of China (No. 19901021) and Beijing Education Commission Foundation, Natural Science Foundation of Beijing (1013006). References:[1]Coifman,R. and Meyer,Y. ,Au déla Des Opérateurs Pseudo-Différentiles,Astérisque 57(1978),1-185.[2]Alvarez,J. ,Bagby,R. ,Kurtz,D. and Pérez,C. ,Weighted Estimates for Commutators of Linear Operators,Studia Math. 104 (1993),195-[2]09.[3]Hu G. and Lu S. Z. ,The Commutator of the Bochner-Riesz Operator,Tohoku Math. J. 48(1996) ,259-266.[4]Duoandikoetxea,J. ,Weighted Norm Inequalities for Homogeneous Singular Integrals,Trans.Amer,Math. Soc.[3]36(1993),869-880.[5]Stein,E. M. and Weiss,G. ,Interpolation of Operators with Change of Measures,Trans.Amer. Math. Soc. 87(1958),159-172.[6]Zaanea,A. C. ,Interpolation,North-Holland,1967.[7]Ding Y. and Lu S. Z. ,Weighted Lp-Bounedness for Higher Order Commutators of Oscillatory Singular Integrals,Tohoku Math. J. 48(1996),437-449.Manuscript Received:1999年12月22日Published:2001年9月1日

  9. Evaluation of Regression Models of Balance Calibration Data Using an Empirical Criterion

    Science.gov (United States)

    Ulbrich, Norbert; Volden, Thomas R.

    2012-01-01

    An empirical criterion for assessing the significance of individual terms of regression models of wind tunnel strain gage balance outputs is evaluated. The criterion is based on the percent contribution of a regression model term. It considers a term to be significant if its percent contribution exceeds the empirical threshold of 0.05%. The criterion has the advantage that it can easily be computed using the regression coefficients of the gage outputs and the load capacities of the balance. First, a definition of the empirical criterion is provided. Then, it is compared with an alternate statistical criterion that is widely used in regression analysis. Finally, calibration data sets from a variety of balances are used to illustrate the connection between the empirical and the statistical criterion. A review of these results indicated that the empirical criterion seems to be suitable for a crude assessment of the significance of a regression model term as the boundary between a significant and an insignificant term cannot be defined very well. Therefore, regression model term reduction should only be performed by using the more universally applicable statistical criterion.

  10. The New DSM-5 Impairment Criterion: A Challenge to Early Autism Spectrum Disorder Diagnosis?

    Science.gov (United States)

    Zander, Eric; Bölte, Sven

    2015-01-01

    The possible effect of the DSM-5 impairment criterion on diagnosing autism spectrum disorder (ASD) in young children was examined in 127 children aged 20-47 months with a DSM-IV-TR clinical consensus diagnosis of ASD. The composite score of the Vineland Adaptive Behavior Scales (VABS) served as a proxy for the DSM-5 impairment criterion. When…

  11. Evidence for the Criterion Validity and Clinical Utility of the Pathological Narcissism Inventory

    Science.gov (United States)

    Thomas, Katherine M.; Wright, Aidan G. C.; Lukowitsky, Mark R.; Donnellan, M. Brent; Hopwood, Christopher J.

    2012-01-01

    In this study, the authors evaluated aspects of criterion validity and clinical utility of the grandiosity and vulnerability components of the Pathological Narcissism Inventory (PNI) using two undergraduate samples (N = 299 and 500). Criterion validity was assessed by evaluating the correlations of narcissistic grandiosity and narcissistic…

  12. Energy-efficient induction motors designing with application of a modified criterion of reduced costs

    Directory of Open Access Journals (Sweden)

    V.S. Petrushin

    2014-03-01

    Full Text Available The paper introduces a modified criterion of reduced costs that employs coefficients of operation significance and priority of ohmic loss accounting to allow matching maximum efficiency with minimum reduced costs. Impact of the inflation factor on the criterion of reduced costs is analyzed.

  13. A Controlled Evaluation of the Distress Criterion for Binge Eating Disorder

    Science.gov (United States)

    Grilo, Carlos M.; White, Marney A.

    2011-01-01

    Objective: Research has examined various aspects of the validity of the research criteria for binge eating disorder (BED) but has yet to evaluate the utility of Criterion C, "marked distress about binge eating." This study examined the significance of the marked distress criterion for BED using 2 complementary comparison groups. Method: A total of…

  14. A Controlled Evaluation of the Distress Criterion for Binge Eating Disorder

    Science.gov (United States)

    Grilo, Carlos M.; White, Marney A.

    2011-01-01

    Objective: Research has examined various aspects of the validity of the research criteria for binge eating disorder (BED) but has yet to evaluate the utility of Criterion C, "marked distress about binge eating." This study examined the significance of the marked distress criterion for BED using 2 complementary comparison groups. Method:…

  15. Evidence for the Criterion Validity and Clinical Utility of the Pathological Narcissism Inventory

    Science.gov (United States)

    Thomas, Katherine M.; Wright, Aidan G. C.; Lukowitsky, Mark R.; Donnellan, M. Brent; Hopwood, Christopher J.

    2012-01-01

    In this study, the authors evaluated aspects of criterion validity and clinical utility of the grandiosity and vulnerability components of the Pathological Narcissism Inventory (PNI) using two undergraduate samples (N = 299 and 500). Criterion validity was assessed by evaluating the correlations of narcissistic grandiosity and narcissistic…

  16. Criterion 7: Legal, institutional, and economic framework for forest conservation and sustainable management

    Science.gov (United States)

    Stephen R. Shifley; Francisco X. Aguilar; Nianfu Song; Susan I. Stewart; David J. Nowak; Dale D. Gormanson; W. Keith Moser; Sherri Wormstead; Eric J. Greenfield

    2012-01-01

    This criterion focuses on the social context of forests—the laws, policies, administrative rules, and social and economic institutions—that governs forest resource management and use. What society permits or restricts, encourages or discourages all influence the sustainability of forest resources. Criterion 7 captures this by turning attention to all the different...

  17. Perspectives on Norm-Referenced and Criterion-Referenced Grading in Introductory Speech Performance Courses.

    Science.gov (United States)

    Behnke, Ralph R.; Sawyer, Chris R.

    1998-01-01

    Integrates and amalgamates norm-referenced and criterion-referenced perspectives in a manner that is particularly appropriate for use in basic or introductory speech communication performance courses. Notes that students prefer criterion-referenced grading for performances but prefer norm-referenced grading for content components of the course.…

  18. A criterion-related validity study of the nursing-care dependency (NCD) scale

    NARCIS (Netherlands)

    Dijkstra, A.; Buist, G.; Dassen, Th.W.N.

    1998-01-01

    The purpose of this study was to examine some aspects of the criterion-related validity of the Nursing-Care Dependency (NCD) scale. This 15-item counting scale has recently been developed for assessing the care dependency of demented or mentally handicapped in-patients. Its criterion-related validit

  19. A Controlled Evaluation of the Distress Criterion for Binge Eating Disorder

    Science.gov (United States)

    Grilo, Carlos M.; White, Marney A.

    2011-01-01

    Objective: Research has examined various aspects of the validity of the research criteria for binge eating disorder (BED) but has yet to evaluate the utility of Criterion C, "marked distress about binge eating." This study examined the significance of the marked distress criterion for BED using 2 complementary comparison groups. Method:…

  20. Maximum twin shear stress factor criterion for sliding mode fracture initiation

    Institute of Scientific and Technical Information of China (English)

    黎振兹; 李慧剑; 黎晓峰; 周洪彬; 郝圣旺

    2002-01-01

    Previous researches on the mixed mode fracture initiation criteria were mostly focused on opening mode fracture. In this study, the authors proposed a new criterion for mixed mode sliding fracture initiation, which is the maximum twin shear stress factor criterion. The authors studied a finite width plate with central slant crack, subject to a far-field uniform uniaxial tensile or compressive stress.

  1. The New DSM-5 Impairment Criterion: A Challenge to Early Autism Spectrum Disorder Diagnosis?

    Science.gov (United States)

    Zander, Eric; Bölte, Sven

    2015-01-01

    The possible effect of the DSM-5 impairment criterion on diagnosing autism spectrum disorder (ASD) in young children was examined in 127 children aged 20-47 months with a DSM-IV-TR clinical consensus diagnosis of ASD. The composite score of the Vineland Adaptive Behavior Scales (VABS) served as a proxy for the DSM-5 impairment criterion. When…

  2. Comparing the Pedagogical Benefits of Both Criterion and Teacher Feedback on Japanese EFL Students' Writing

    Science.gov (United States)

    Heffernan, Neil; Otoshi, Junko

    2015-01-01

    This paper reports on a classroom-based inquiry using quantitative methods conducted with Japanese EFL students' writing practice using ETS's Criterion. The purpose of the study is to examine the actual effects of teachers' feedback on students' writing on Criterion. Twelve university students in Japan participated in this study, while completing…

  3. Specificity matters: criterion-related validity of contextualized and facet measures of conscientiousness in predicting college student performance.

    Science.gov (United States)

    Woo, Sang Eun; Jin, Jing; LeBreton, James M

    2015-01-01

    To enhance the predictive validity of self-report personality measures, 2 distinct ways of increasing specificity of personality measures have been proposed in the literature-contextual specificity (i.e., providing a contextual referent) and content specificity (i.e., focusing on more specific constructs such as the Big Five facets). This study extends this line of research by examining whether there is an optimal way to configure, align, or integrate contextual and content specificity using measures of conscientiousness to predict college student success. A sample of 478 undergraduate students completed 4 measures of conscientiousness that varied in the level of content and contextual specificity. These forms of specificity were crossed to yield 4 distinct measures of conscientiousness. We then evaluated and compared the relative importance and the incremental importance of these different measures in the prediction of academic success. Superior predictive validity was found for both contextualized and facet measures of conscientiousness compared to a measure of global conscientiousness in predicting grade-point average and a broader behavioral criterion of student performance. When contextual and content specificity approaches were compared and combined, we observed the strongest predictive validity when the level of specificity is appropriately matched between predictor and criterion.

  4. Does the Lowest Bid Price Evaluation Criterion Make for a More Efficient Public Procurement Selection Criterion? (Case of the Czech Republic

    Directory of Open Access Journals (Sweden)

    Ochrana František

    2015-06-01

    Full Text Available Through the institute of public procurement a considerable volume of financial resources is allocated. It is therefore in the interest of contracting entities to seek ways of how to achieve an efficient allocation of resources. Some public contract-awarding entities, along with some public-administration authorities in the Czech Republic, believe that the use of a single evaluation criterion (the lowest bid price results in a more efficient tender for a public contract. It was found that contracting entities in the Czech Republic strongly prefer to use the lowest bid price criterion. Within the examined sample, 86.5 % of public procurements were evaluated this way. The analysis of the examined sample of public contracts proved that the choice of an evaluation criterion, even the preference of the lowest bid price criterion, does not have any obvious impact on the final cost of a public contract. The study concludes that it is inappropriate to prefer the criterion of the lowest bid price within the evaluation of public contracts that are characterised by their complexity (including public contracts for construction works and public service contracts. The findings of the Supreme Audit Office related to the inspection of public contracts indicate that when using the lowest bid price as an evaluation criterion, a public contract may indeed be tendered with the lowest bid price, but not necessarily the best offer in terms of supplied quality. It is therefore not appropriate to use the lowest bid price evaluation criterion to such an extent for the purpose of evaluating work and services. Any improvement to this situation requires a corresponding amendment to the Law on Public Contracts and mainly a radical change in the attitude of the Office for the Protection of Competition towards proposed changes, as indicated within the conclusions and recommendations proposed by this study.

  5. Objective Error Criterion for Evaluation of Mapping Accuracy Based on Sensor Time-of-Flight Measurements

    Directory of Open Access Journals (Sweden)

    Billur Barshan

    2008-12-01

    Full Text Available An objective error criterion is proposed for evaluating the accuracy of maps of unknown environments acquired by making range measurements with different sensing modalities and processing them with different techniques. The criterion can also be used for the assessment of goodness of fit of curves or shapes fitted to map points. A demonstrative example from ultrasonic mapping is given based on experimentally acquired time-of-flight measurements and compared with a very accurate laser map, considered as absolute reference. The results of the proposed criterion are compared with the Hausdorff metric and the median error criterion results. The error criterion is sufficiently general and flexible that it can be applied to discrete point maps acquired with other mapping techniques and sensing modalities as well.

  6. Asymptotic Effectiveness of the Event-Based Sampling According to the Integral Criterion

    Directory of Open Access Journals (Sweden)

    Marek Miskowicz

    2007-01-01

    Full Text Available A rapid progress in intelligent sensing technology creates new interest in a development of analysis and design of non-conventional sampling schemes. The investigation of the event-based sampling according to the integral criterion is presented in this paper. The investigated sampling scheme is an extension of the pure linear send-on- delta/level-crossing algorithm utilized for reporting the state of objects monitored by intelligent sensors. The motivation of using the event-based integral sampling is outlined. The related works in adaptive sampling are summarized. The analytical closed-form formulas for the evaluation of the mean rate of event-based traffic, and the asymptotic integral sampling effectiveness, are derived. The simulation results verifying the analytical formulas are reported. The effectiveness of the integral sampling is compared with the related linear send-on-delta/level-crossing scheme. The calculation of the asymptotic effectiveness for common signals, which model the state evolution of dynamic systems in time, is exemplified.

  7. Breakdown of universal Lindemann criterion in the melting of Lennard-Jones polydisperse solids

    Indian Academy of Sciences (India)

    SARMISTHA SARKAR; CHANDRAMOHAN JANA; BIMAN BAGCHI

    2017-07-01

    It is commonly believed that melting occurs when mean square displacement (MSD) of a particle of crystalline solid exceeds a threshold value. This is known as the Lindemann criterion, first introduced in the year of 1910 by Lindemann. However, Chakravarty et al., demonstrated that this common wisdom is inadequatebecause the MSD at melting can be temperature dependent when pressure is also allowed to vary along the coexistence line of the phase diagram [Chakravarty C, Debenedetti P G and Stillinger F H 2007 J. Chem. Phys. 126 204508]. We show here by extensive molecular dynamics simulation of both two and three dimensional polydisperse Lennard-Jones solids that particles on the small and large limits of size distribution exhibit substantially different Lindemann ratio at melting. Despite all the dispersion in MSD, melting is found tobe first order in both the dimensions at 5–10% dispersity in size. Sharpness of the transition is incommensurate with the different rate of growth of MSD. The increased MSD values of smaller particles play a role in the segregation of them prior to melting.

  8. The analemma criterion: accidental quasi-satellites are indeed true quasi-satellites

    CERN Document Server

    Marcos, C de la Fuente

    2016-01-01

    In the Solar system, a quasi-satellite is an object that follows a heliocentric path with an orbital period that matches almost exactly that of a host body (planetary or not). The trajectory is of such nature that, without being gravitationally attached, the value of the angular separation between host and quasi-satellite as seen from the Sun remains confined within relatively narrow limits for time spans that exceed the length of the host's sidereal orbital period. Here, we show that under these conditions, a quasi-satellite traces an analemma in the sky as observed from the host in a manner similar to that found for geosynchronous orbits. The analemmatic curve (figure-eight-, teardrop-, ellipse-shaped) results from the interplay between the tilt of the rotational axis of the host and the properties of the orbit of the quasi-satellite. The analemma criterion can be applied to identify true quasi-satellite dynamical behaviour using observational or synthetic astrometry and it is tested for several well docume...

  9. 河北平原农田耗水与地下水动态及粮食生产相互关系分析%Correlation among farmland water consumption, grain yield and groundwater dynamics in the Hebei Plain

    Institute of Scientific and Technical Information of China (English)

    袁再健; 许元则; 谢栌乐

    2014-01-01

    农田耗水是河北平原地下水资源消耗的主体,农田耗水与地下水动态、粮食生产互制机理研究可为农业节水提供重要依据。基于1981-2010年河北省经济统计年鉴、地下水开采量与地下水位、常规气象等数据,分析了河北平原近30年来农田耗水、粮食产量、降水量、地下水等动态变化特征,揭示了它们之间的相互响应关系。结果表明,近30年来,河北平原农田耗水总量约722.4 km3,生产粮食约5.9×108t,开采地下水约440 km3(其中约330 km3用于农田灌溉),地下水位共下降约11.5 m;河北平原农田耗水与粮食产量总体呈逐年上升趋势,尽管2000年以来地下水开采量有所减少,但地下水位一直持续下降;农田耗水与地下水开采量、地下水埋深、粮食产量相互之间关系密切,每生产1 t粮食所消耗的水资源约1224.4 m3(包括地下水597.1 m3),而地下水开采量每增加1 km3,河北平原地下水位实际下沉约0.03 m;农田耗水、地下水埋深均与年降雨量无明显相关性,由于降水入渗、灌溉渗漏不足以弥补开采的地下水,超采是引起河北平原地下水位持续下降的直接原因。因此,进一步发展节水农业、提高灌溉效率是促进河北平原农业可持续发展的必然选择。%Farmland water consumption accounts for most of the groundwater consumption in the Hebei Plain. Research on the interaction mechanism of farmland water consumption, groundwater dynamics and grain production could provide critical evidence for water-saving agriculture. Based on Hebei Province economic statistical data, groundwater exploitation data, groundwater level data and conventional meteorological data for 1981-2010, this paper analyzed the changes in farmland water consumption, grain production, precipitation and groundwater level in the Hebei Plain in the recent 30 years. Their correlation was also discussed. The results showed that in the past 30 years

  10. A New Stability Criterion for the Hot Deformation Behavior of Materials: Application to the AZ31 Magnesium Alloy

    Science.gov (United States)

    Rieiro, Ignacio; Carsí, Manuel; Ruano, Oscar A.

    2017-07-01

    In the present work, a new stability criterion is presented that uses the single sine hyperbolic equation of Garofalo for all values of the thermomechanical variables of the hot-working process. In this procedure, the efficiency and stability are calculated for each \\dot{ɛ} and T by means of this equation. This is carried out directly applying the Garofalo equation on Lyapunov conditions in the framework of the dynamic material model (DMM), which simplifies operations and minimizes errors. This procedure, therefore, is straightforward, starting with experimental data and reaching the new established Lyapunov stability criterion. It is an alternative to the stability conditions using Lyapunov criteria, as established by Malas and Gegel and Prasad, where the strain-rate-sensitivity exponent, m, was determined by fitting the curve strain rate, \\dot{ɛ} , vs stress, σ, by means of a potential equation named power law, or by a polynomial of second or third degree, and calculating the slope of the logarithmic curve at each point using successive derivatives. In addition, a revision of various stability criteria and calculations of efficiency is conducted to delineate the framework of our new criterion. The developed method allows obtaining inequations that determine the more or less stable regions in the form of maps. These maps predict optimal temperatures and strain rates that are different from those given in the maps of Malas and Gegel and Prasad, although significant matches with various authors may also be observed. An analysis of maps for the magnesium alloy AZ31 based on various methods and models was performed to compare the predictions with the experimental results of other authors.

  11. Application of Artificial Neural Networks in Canola Crop Yield Prediction

    Directory of Open Access Journals (Sweden)

    S. J. Sajadi

    2014-02-01

    Full Text Available Crop yield prediction has an important role in agricultural policies such as specification of the crop price. Crop yield prediction researches have been based on regression analysis. In this research canola yield was predicted using Artificial Neural Networks (ANN using 11 crop year climate data (1998-2009 in Gonbad-e-Kavoos region of Golestan province. ANN inputs were mean weekly rainfall, mean weekly temperature, mean weekly relative humidity and mean weekly sun shine hours and ANN output was canola yield (kg/ha. Multi-Layer Perceptron networks (MLP with Levenberg-Marquardt backpropagation learning algorithm was used for crop yield prediction and Root Mean Square Error (RMSE and square of the Correlation Coefficient (R2 criterions were used to evaluate the performance of the ANN. The obtained results show that the 13-20-1 network has the lowest RMSE equal to 101.235 and maximum value of R2 equal to 0.997 and is suitable for predicting canola yield with climate factors.

  12. [Dynamic morbidity of children as a evaluation criterion for renovation of aluminum manufacturing industries].

    Science.gov (United States)

    Gurvich, V B; Plotko, E G; Seliankina, K P; Nadeenko, V G; Ryzhov, V V; Saĭchenko, S P; Veprintsev, V V

    2004-01-01

    Negative pollution effects from atmospheric discharges by aluminium facilities exerted on population health can be traced by the parameters of the reproductive function in women, physical development of newborns, general and differential morbidity of children aged below one year as well as by anthropometric signs in birth, morbidity of children and adults, mortality, including due to oncology. The introduction of modern technologies including the preliminarily fire anode treatment and the use of highly effective methods of purification of industrial wastes cut the concentration (in atmospheric air) of anhydrous hydrogen fluoride and of solid fluorides as well as of aluminium to maximum permissible concentration; it also essentially reduced the content of benzapilene. A better atmospheric air observed yet in the course of renovation contributed to a lower morbidity of children, aged below one year, as well as to the prevalence of diseases affecting the eyes, respiratory and digestive organs, skin and subcutaneous cellular tissue; it also cuts the number of congenital anomalies versus the data obtained in a neighboring district.

  13. Correlation Analysis of some Growth, Yield, Yield Components and ...

    African Journals Online (AJOL)

    Keywords: Correlation, Wheat; growth, yield, yield components, grain quality. INTRODUCTION. Wheat ... macaroni, biscuits, cookies, cakes, pasta, noodles and couscous; beer, many .... and 6 WAS which ensured weed free plots. Fertilizer was ...

  14. Efficiency of event-based sampling according to error energy criterion.

    Science.gov (United States)

    Miskowicz, Marek

    2010-01-01

    The paper belongs to the studies that deal with the effectiveness of the particular event-based sampling scheme compared to the conventional periodic sampling as a reference. In the present study, the event-based sampling according to a constant energy of sampling error is analyzed. This criterion is suitable for applications where the energy of sampling error should be bounded (i.e., in building automation, or in greenhouse climate monitoring and control). Compared to the integral sampling criteria, the error energy criterion gives more weight to extreme sampling error values. The proposed sampling principle extends a range of event-based sampling schemes and makes the choice of particular sampling criterion more flexible to application requirements. In the paper, it is proved analytically that the proposed event-based sampling criterion is more effective than the periodic sampling by a factor defined by the ratio of the maximum to the mean of the cubic root of the signal time-derivative square in the analyzed time interval. Furthermore, it is shown that the sampling according to energy criterion is less effective than the send-on-delta scheme but more effective than the sampling according to integral criterion. On the other hand, it is indicated that higher effectiveness in sampling according to the selected event-based criterion is obtained at the cost of increasing the total sampling error defined as the sum of errors for all the samples taken.

  15. Stress-strain curves for different loading paths and yield loci of aluminum alloy sheets

    Institute of Scientific and Technical Information of China (English)

    WU Xiang-dong; WAN Min; HAN Fei; WANG Hai-bo

    2006-01-01

    To carry out biaxial tensile test in sheet metal, the biaxial tensile testing system was established. True stress-true strain curves of three kinds of aluminum alloy sheets for loading ratios of 4:1, 4:2, 4:3, 4:4, 3:4, 2:4 and 1:4 were obtained by conducting biaxial tensile test in the established testing systems. It shows that the loading path has a significant influence on the stress-strain curves and as the loading ratio increases from 4:1 to 4:4, the stress-strain curve becomes higher and n-value becomes larger.Experimental yield points for three aluminum alloy sheets from 0.2% to 2% plastic strain were determined based on the equivalent plastic work. And the geometry of the experimental yield loci were compared with the yield loci calculated from several existing yield criteria. The analytical result shows that the Barlat89 and Hosford yield criterion describe the general trends of the experimental yield loci of aluminum alloy sheets well, whereas the Mises yield criterion overestimates the yield stress in all the contours.

  16. A time step criterion for the stable numerical simulation of hydraulic fracturing

    Science.gov (United States)

    Juan-Lien Ramirez, Alina; Löhnert, Stefan; Neuweiler, Insa

    2017-04-01

    The process of propagating or widening cracks in rock formations by means of fluid flow, known as hydraulic fracturing, has been gaining attention in the last couple of decades. There is growing interest in its numerical simulation to make predictions. Due to the complexity of the processes taking place, e.g. solid deformation, fluid flow in an open channel, fluid flow in a porous medium and crack propagation, this is a challenging task. Hydraulic fracturing has been numerically simulated for some years now [1] and new methods to take more of its processes into account (increasing accuracy) while modeling in an efficient way (lower computational effort) have been developed in recent years. An example is the use of the Extended Finite Element Method (XFEM), whose application originated within the framework of solid mechanics, but is now seen as an effective method for the simulation of discontinuities with no need for re-meshing [2]. While more focus has been put to the correct coupling of the processes mentioned above, less attention has been paid to the stability of the model. When using a quasi-static approach for the simulation of hydraulic fracturing, choosing an adequate time step is not trivial. This is in particular true if the equations are solved in a staggered way. The difficulty lies within the inconsistency between the static behavior of the solid and the dynamic behavior of the fluid. It has been shown that too small time steps may lead to instabilities early into the simulation time [3]. While the solid reaches a stationary state instantly, the fluid is not able to achieve equilibrium with its new surrounding immediately. This is why a time step criterion has been developed to quantify the instability of the model concerning the time step. The presented results were created with a 2D poroelastic model, using the XFEM for both the solid and the fluid phases. An embedded crack propagates following the energy release rate criteria when the fluid pressure

  17. Exclusion as a Criterion for Selecting Socially Vulnerable Population Groups

    Directory of Open Access Journals (Sweden)

    Aleksandra Anatol’evna Shabunova

    2016-05-01

    Full Text Available The article considers theoretical aspects of a scientific research “The Mechanisms for Overcoming Mental Barriers of Inclusion of Socially Vulnerable Categories of the Population for the Purpose of Intensifying Modernization in the Regional Community” (RSF grant No. 16-18-00078. The authors analyze the essence of the category of “socially vulnerable groups” from the legal, economic and sociological perspectives. The paper shows that the economic approach that uses the criterion “the level of income and accumulated assets” when defining vulnerable population groups prevails in public administration practice. The legal field of the category based on the economic approach is defined by the concept of “the poor and socially unprotected categories of citizens”. With the help of the analysis of theoretical and methodological aspects of this issue, the authors show that these criteria are a necessary but not sufficient condition for classifying the population as being socially vulnerable. Foreign literature associates the phenomenon of vulnerability with the concept of risks, with the possibility of households responding to them and with the likelihood of losing the well-being (poverty theory; research areas related to the means of subsistence, etc.. The asset-based approaches relate vulnerability to the poverty that arises due to lack of access to tangible and intangible assets. Sociological theories presented by the concept of social exclusion pay much attention to the breakdown of social ties as a source of vulnerability. The essence of social exclusion consists in the inability of people to participate in important aspects of social life (in politics, labor markets, education and healthcare, cultural life, etc. though they have all the rights to do so. The difference between the concepts of exclusion and poverty is manifested in the displacement of emphasis from income inequality to limited access to rights. Social exclusion is

  18. A new variant selection criterion for twin variants in titanium alloys. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Schuman, Christophe [Laboratoire d' Etude des Microstructures et de Mecanique des Materiaux, LEM3, CNRS 7239, Universite Paul Verlaine - Metz, Ile du Saulcy, Metz (France); Bao, Lei; Lecomte, Jean Sebastien; Zhang, Yudong; Raulot, Jean Marc; Philippe, Marie Jeanne; Esling, Claude [LEM3, CNRS 7239, Universite Paul Verlaine - Metz, Ile du Saulcy, Metz (France)

    2012-05-15

    A new selection criterion to explain the activation of the twinning variant is proposed. This criterion is based on the calculation of the deformation energy to create a primary twin. The calculation takes into account the effect of the grain size using a Hall-Petch type relation. This criterion allows to obtain a very good prediction for the twin family selection and twin variant selection. The calculations are compared with the experimental results obtained on T40 (ASTM grade 2) deformed by Channel Die compression. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Latent Class Analysis of Incomplete Data via an Entropy-Based Criterion.

    Science.gov (United States)

    Larose, Chantal; Harel, Ofer; Kordas, Katarzyna; Dey, Dipak K

    2016-09-01

    Latent class analysis is used to group categorical data into classes via a probability model. Model selection criteria then judge how well the model fits the data. When addressing incomplete data, the current methodology restricts the imputation to a single, pre-specified number of classes. We seek to develop an entropy-based model selection criterion that does not restrict the imputation to one number of clusters. Simulations show the new criterion performing well against the current standards of AIC and BIC, while a family studies application demonstrates how the criterion provides more detailed and useful results than AIC and BIC.

  20. A Less Conservative Stability Criterion for Delayed Stochastic Genetic Regulatory Networks

    Directory of Open Access Journals (Sweden)

    Tingting Yu

    2014-01-01

    Full Text Available This paper concerns the problem of stability analysis for delayed stochastic genetic regulatory networks. By introducing an appropriate Lyapunov-Krasovskii functional and employing delay-range partition approach, a new stability criterion is given to ensure the mean square stability of genetic regulatory networks with time-varying delays and stochastic disturbances. The stability criterion is given in the form of linear matrix inequalities, which can be easily tested by the LMI Toolbox of MATLAB. Moreover, it is theoretically shown that the obtained stability criterion is less conservative than the one in W. Zhang et al., 2012. Finally, a numerical example is presented to illustrate our theory.

  1. The index of ideality of correlation: A criterion of predictability of QSAR models for skin permeability?

    Science.gov (United States)

    Toropova, Alla P; Toropov, Andrey A

    2017-05-15

    New criterion of the predictive potential of quantitative structure-property/activity relationships (QSPRs/QSARs) is suggested. This criterion is calculated with utilization of the correlation coefficient between experimental and calculated values of endpoint for the calibration set, with taking into account the positive and negative dispersions between experimental and calculated values. The utilization of this criterion improves the predictive potential of QSAR models of dermal permeability coefficient, logKp (cm/h). Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Yield enhancement with DFM

    Science.gov (United States)

    Paek, Seung Weon; Kang, Jae Hyun; Ha, Naya; Kim, Byung-Moo; Jang, Dae-Hyun; Jeon, Junsu; Kim, DaeWook; Chung, Kun Young; Yu, Sung-eun; Park, Joo Hyun; Bae, SangMin; Song, DongSup; Noh, WooYoung; Kim, YoungDuck; Song, HyunSeok; Choi, HungBok; Kim, Kee Sup; Choi, Kyu-Myung; Choi, Woonhyuk; Jeon, JoongWon; Lee, JinWoo; Kim, Ki-Su; Park, SeongHo; Chung, No-Young; Lee, KangDuck; Hong, YoungKi; Kim, BongSeok

    2012-03-01

    A set of design for manufacturing (DFM) techniques have been developed and applied to 45nm, 32nm and 28nm logic process technologies. A noble technology combined a number of potential confliction of DFM techniques into a comprehensive solution. These techniques work in three phases for design optimization and one phase for silicon diagnostics. In the DFM prevention phase, foundation IP such as standard cells, IO, and memory and P&R tech file are optimized. In the DFM solution phase, which happens during ECO step, auto fixing of process weak patterns and advanced RC extraction are performed. In the DFM polishing phase, post-layout tuning is done to improve manufacturability. DFM analysis enables prioritization of random and systematic failures. The DFM technique presented in this paper has been silicon-proven with three successful tape-outs in Samsung 32nm processes; about 5% improvement in yield was achieved without any notable side effects. Visual inspection of silicon also confirmed the positive effect of the DFM techniques.

  3. Maximizing ROI with yield management

    National Research Council Canada - National Science Library

    Neil Snyder

    2001-01-01

    .... the technology is based on the concept of yield management, which aims to sell the right product to the right customer at the right price and the right time therefore maximizing revenue, or yield...

  4. Shortcomings in wheat yield predictions

    Science.gov (United States)

    Semenov, Mikhail A.; Mitchell, Rowan A. C.; Whitmore, Andrew P.; Hawkesford, Malcolm J.; Parry, Martin A. J.; Shewry, Peter R.

    2012-06-01

    Predictions of a 40-140% increase in wheat yield by 2050, reported in the UK Climate Change Risk Assessment, are based on a simplistic approach that ignores key factors affecting yields and hence are seriously misleading.

  5. Multiaxial yield surface of transversely isotropic foams: Part II—Experimental

    Science.gov (United States)

    Shafiq, Muhammad; Ayyagari, Ravi Sastri; Ehaab, Mohammad; Vural, Murat

    2015-03-01

    A robust understanding and modeling of the yield behavior in solid foams under complex stress states is essential to design and analysis of optimal structures using these lightweight materials. In pursuit of this objective a new custom-built Multi-Axial Testing Apparatus (MATA) is developed to probe the yield surface of transversely isotropic Divinycell H-100 PVC foam under a multitude of uniaxial, biaxial and triaxial strain paths. Experimental yield data produced constitutes the most comprehensive data set ever produced for any foam as it covers the entire spectrum of stress paths from hydrostatic compression to hydrostatic tension. Experimental results reveal that yielding in foams exhibits not only a quadratic pressure dependence, which is widely recognized in literature, but also a significant linear pressure dependence, which has been largely overlooked in previous studies. A new energy-based yield criterion developed for transversely isotropic foams is also validated using the experimental yield data.

  6. Bayesian and Akaike’s information criterions for some multivariate tests of homogeneity with applications in multisample clustering

    OpenAIRE

    Jelenkowska, Teresa H.

    2002-01-01

    W pracy zostały przedstawione dwa kryteria dotyczące selekcji modeli, mianowicie kryterium Akaike: AIC (Akaike’s Information Criterion) i kryterium bayesowskie: BIC (Bayesian Information Criterion). This paper studies the AlC and B1C (Akaike’s and Bayesian Information Criterion) replacement for: - Box’s (1949) M test of the homogeneity of covariances, - Wilks’ (1932) Л criterion for testing the equality of mean vectors and - likelihood ratio test of the complete homogenei...

  7. A criterion for high-cycle fatigue life and fatigue limit prediction in biaxial loading conditions

    Institute of Scientific and Technical Information of China (English)

    ukasz Pejkowski; Dariusz Skibicki

    2016-01-01

    This paper presents a criterion for high-cycle fatigue life and fatigue strength estimation under periodic proportional and non-proportional cyclic loading. The cri-terion is based on the mean and maximum values of the second invariant of the stress deviator. Important elements of the criterion are: function of the non-proportionality of fatigue loading and the materials parameter that expresses the materials sensitivity to non-proportional loading. The methods for the materials parameters determination uses three S–N curves: tension–compression, torsion, and any non-proportional loading proposed. The criterion has been verified using experimental data, and the results are included in the paper. These results should be considered as promis-ing. The paper also includes a proposal for multiaxial fatigue models classification due to the approach for the non-proportionality of loading.

  8. Local Existence and Continuation Criterion for Solutions of the Spherically Symmetric Einstein-Vlasov-Maxwell System

    CERN Document Server

    Noundjeu, P

    2003-01-01

    Using the iterative Scheme we prove the local existence and uniqueness of solutions of the spherically symmetric Einstein-Vlasov-Maxwell system with small initial data. We prove a continuation criterion to global in-time solutions.

  9. 76 FR 33740 - Final Priorities and Selection Criterion; National Institute on Disability and Rehabilitation...

    Science.gov (United States)

    2011-06-09

    ... the spinal cord and subsequent human physical activity and movement. Discussion: We are establishing... spinal cord and subsequent physical activity and movement, as suggested by the commenter. Changes: None... Final Priorities and Selection Criterion; National Institute on Disability and Rehabilitation...

  10. BLOW-UP CRITERION OF SMOOTH SOLUTIONS TO THE MHD EQUATIONS IN BESOV SPACES

    Institute of Scientific and Technical Information of China (English)

    YUAN Baoquan

    2005-01-01

    In this paper we discuss the logarithmic Sobolev inequalities in Besov spaces,and show their applications to the blow-up criterion of smooth solutions to the incompressible magneto-hydrodynamics equations.

  11. TEMPERATURE-DEFORMATION CRITERION OF OPTIMIZATION OF FINE DRAWING HIGH CARBON WIRE ROUTE

    Directory of Open Access Journals (Sweden)

    Y. L. Bobarikin

    2012-01-01

    Full Text Available The temperature-deformation criterion of assessment and optimization of routes of the thin high-carbon wire drawing enabling to increase plastic properties of wire at retaining of its durability is offered.

  12. METHOD OF CHOICE OF A TECHNICAL SYSTEM FOR PROJECT IMPLEMENTATION BASING UPON SITUATIONAL EFFICIENCY CRITERION

    Directory of Open Access Journals (Sweden)

    Valentyn Chimshir

    2014-06-01

    Full Text Available This work demonstrates correlation between technical system efficiency criterion and complex system efficiency criterion in which the said technical system operates. Furthermore, the said correlation may be expressed by means of a set of separate particular criteria of a complex system. Methodology of choosing the technical system for project implementation within the framework of project-oriented organization of a complex sociotechnical system is also proposed. The offered method provides for a basis algorithm for calculations of situational efficiency criterion for technical system supposed to be applied within the project. The criterion in question indicates the extent to which the technical system is suitable for implementing its objective under specific conditions arising at various stages of the project implementation.

  13. STRENGTH CRITERION FOR PLAIN CONCRETE UNDER MULTIAXIAL STRESS BASED ON DAMAGE POISSON'S RATIO

    Institute of Scientific and Technical Information of China (English)

    Ding Faxing; Yu Zhiwu

    2006-01-01

    A new unified strength criterion in the principal stress space has been proposed for use with normal strength concrete (NC) and high strength concrete (HSC) in compressioncompression-tension, compression-tension-tension, triaxial tension, and biaxial stress states. The study covers concrete with strengths ranging from 20 to 130 Mpa. The conception of damage Poisson's ratio is defined and the expression for damage Poisson's ratio is determined basically.The failure mechanism of concrete is illustrated, which points out that damage Poisson's ratio is the key to determining the failure of concrete. Furthermore, for the concrete under biaxial stress conditions, the unified strength criterion is simplified and a simplified strength criterion in the form of curves is also proposed. The strength criterion is physically meaningful and easy to calculate, which can be applied to analytic solution and numerical solution of concrete structures.

  14. Reply to Comment on "Kinetic Theory of the Presheath and the Bohm Criterion"

    CERN Document Server

    Baalrud, S D; 10.1088/0963-0252/21/6/068002

    2012-01-01

    In his comment, Riemann defends the conventional kinetic Bohm criterion on the basis that the underlying approximations become rigorous in the limit \\lambda_D/l \\rightarrow 0, where \\lambda_D is the Deybe length and l is a collision length scale for the dominant collision process. Here, we expand on our previous arguments showing that the basic assumptions for the justified use of the conventional kinetic Bohm criterion are typically not satisfied in laboratory plasmas. We corroborate our argument with experimental data, as well as data from numerical simulations, showing that the conventional criterion is violated in common situations. In contrast, a formulation based on positive velocity moments of the kinetic equation provides a criterion that both agrees with the experimental data and reduces to the traditional expectations from fluid theory in the appropriate limit.

  15. Einstein-Podolsky-Rosen Steerability Criterion for Two-Qubit Density Matrices

    CERN Document Server

    Chen, Jing-Ling; Ye, Xiang-Jun; Wu, Chunfeng; Kwek, L C; Oh, C H

    2011-01-01

    We propose a criterion ${S}=\\lambda_1+\\lambda_2-(\\lambda_1-\\lambda_2)^2<0$ to detect Einstein-Podolsky-Rosen (EPR) steering for arbitrary two-qubit density matrix $\\rho_{AB}$. Here $\\lambda_1,\\lambda_2$ are respectively the minimal and the second minimal eigenvalues of $\\rho^{T_B}_{AB}$, which is the partial transpose of $\\rho_{AB}$. Numerical results suggest that this criterion is a necessary and sufficient condition for demonstrating steerability of two qubits.

  16. METHOD OF CHOICE OF A TECHNICAL SYSTEM FOR PROJECT IMPLEMENTATION BASING UPON SITUATIONAL EFFICIENCY CRITERION

    OpenAIRE

    Valentyn Chimshir; Anna Chimshir

    2014-01-01

    This work demonstrates correlation between technical system efficiency criterion and complex system efficiency criterion in which the said technical system operates. Furthermore, the said correlation may be expressed by means of a set of separate particular criteria of a complex system. Methodology of choosing the technical system for project implementation within the framework of project-oriented organization of a complex sociotechnical system is also proposed. The offered method provides fo...

  17. Focus detection criterion for refocusing in multi-wavelength digital holography.

    Science.gov (United States)

    Xu, Li; Mater, Mike; Ni, Jun

    2011-08-01

    The majority of focus detection criteria reported is based on amplitude contrast. Due to phase wrapping, phase contrast was previously reported unsuitable for focus finding tasks. By taking the advantage of multi-wavelength digital holography, we propose a new focus detection criterion based on phase contrast. Experimental results are presented to prove the feasibility of the developed criterion. Possible applications of the developed technology include inspecting machined surfaces in the auto industry.

  18. A robust circle criterion observer with application to neural mass models

    OpenAIRE

    2012-01-01

    International audience; A robust circle criterion observer is designed and applied to neural mass models. At present, no existing circle criterion observers apply to the considered models, i.e. the required linear matrix inequality is infeasible. Therefore, we generalise available results to derive a suitable estimation algorithm. Additionally, the design also takes into account input uncertainty and measurement noise. We show how to apply the observer to estimate the mean membrane potential ...

  19. Comparison between cohesive zone models and a coupled criterion for prediction of edge debonding

    OpenAIRE

    Vandellos, T.; Martin, E.; Leguillon, D.

    2014-01-01

    International audience; The onset of edge debonding within a bonded specimen submitted to bending is modeled with two numerical approaches: the coupled criterion and the cohesive zone model. The comparison of the results obtained with the both approaches evidences that (i) the prediction of edge debonding strongly depends on the shape of the cohesive law and (ii) the trapezoidal cohesive law is the most relevant model to predict the edge debonding as compared with the coupled criterion.

  20. A Criterion for Stability of Synchronization and Application to Coupled Chua's Systems

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-Xia; LU Qi-Shao; WANG Qing-Yun

    2009-01-01

    We investigate synchronization in an array network of nearest-neighbor coupled chaotic oscillators. By using of the Lyapunov stability theory and matrix theory, a criterion for stability of complete synchronization is deduced. Meanwhile, an estimate of the critical coupling strength is obtained to ensure achieving chaos synchronization. As an example application, a model of coupled Chua's circuits with linearly bidirectional coupling is studied to verify the validity of the criterion.

  1. The Nyquist Stability Criterion for a Class of Spatially Periodic Systems

    Science.gov (United States)

    2005-01-01

    The Nyquist Stability Criterion For A Class Of Spatially Periodic Systems Makan Fardad and Bassam Bamieh Abstract— The Nyquist stability criterion is...supported in part by AFOSR grant FA9550-04-1-0207 and NSF grant ECS-0323814. M. Fardad and B. Bamieh are with the Department of Me- chanical and Environmental...Engineering, University of California, Santa Barbara, CA 93105-5070. email: fardad @engineering.ucsb.edu, bamieh@engineering.ucsb.edu Our presentation

  2. Airborne molecular contamination: quality criterion for laser and optical components

    Science.gov (United States)

    Otto, Michael

    2015-02-01

    Airborne molecular contaminations (AMCs) have been recognized as a major problem in semiconductor fabrication. Enormous technical and financial efforts are made to remove or at least reduce these contaminations in production environments to increase yield and process stability. It can be shown that AMCs from various sources in laser devices have a negative impact on quality and lifetime of lasers and optical systems. Outgassing of organic compounds, especially condensable compounds were identified as the main source for deterioration of optics. These compounds can lead to hazing on surfaces of optics, degradation of coating, reducing the signal transmission or the laser signal itself and can enhance the probability of laser failure and damage. Sources of organic outgassing can be molding materials, resins, seals, circuit boards, cable insulation, coatings, paints and others. Critical compounds are siloxanes, aromatic amines and high boiling aromatic hydrocarbons like phthalates which are used as softeners in plastic materials. Nowadays all sensitive assembly steps are performed in controlled cleanroom environments to reduce risks of contamination. We will demonstrate a high efficient air filter concept to remove AMCs for production environments with special AMC filters and methods for the qualification and monitoring of these environments. Additionally, we show modern techniques and examples for the pre-qualification of materials. For assembled components, we provide sampling concepts for a routine measurement for process, component and product qualification. A careful selection of previously tested and certified materials and components is essential to guarantee the quality of lasers and optical devices.

  3. Risk-sensitive reinforcement learning algorithms with generalized average criterion

    Institute of Scientific and Technical Information of China (English)

    YIN Chang-ming; WANG Han-xing; ZHAO Fei

    2007-01-01

    A new algorithm is proposed, which immolates the optimality of control policies potentially to obtain the robusticity of solutions. The robusticity of solutions maybe becomes a very important property for a learning system when there exists non-matching between theory models and practical physical system, or the practical system is not static,or the availability of a control action changes along with the variety of time. The main contribution is that a set of approximation algorithms and their convergence results are given. A generalized average operator instead of the general optimal operator max (or min) is applied to study a class of important learning algorithms, dynamic programming algorithms, and discuss their convergences from theoretic point of view. The purpose for this research is to improve the robusticity of reinforcement learning algorithms theoretically.

  4. Practical criterion for the determination of translation factors

    Energy Technology Data Exchange (ETDEWEB)

    Riera, A.

    1984-11-01

    Following an idea of Rankin and Thorson, a method is proposed to determine translation factors in the molecular model of atomic collisions, and for low and intermediate nuclear velocities. The method is based on the minimization of a measure of all (electrostatic and dynamical) couplings between the states included in, and those left out from, the molecular expansion. The properties of this measure are discussed. In particular, its evaluation involves the calculation of a few new matrix elements, and this can be performed analytically when Gaussian-type orbitals are used to construct the wave functions. The method also provides a comparison between all approaches that employ translation factors, and a test of the conditions that are usually enforced on these factors.

  5. A Neural Network Controller for Variable-Speed Variable-Pitch Wind Energy Conversion Systems Using Generalized Minimum Entropy Criterion

    Directory of Open Access Journals (Sweden)

    Mifeng Ren

    2014-01-01

    Full Text Available This paper considers the neural network controller design problem for variable pitch wind energy conversion systems (WECS with non-Gaussian wind speed disturbances in the stochastic distribution control framework. The approach here is used to directly model the unknown control law based on a fixed neural network (the number of layers and nodes in a neural network is fixed without the need to construct a separate model for the WECS. In order to characterize the randomness of the WECS, a generalized minimum entropy criterion is established to train connection weights of the neural network. For the train purpose, both kernel density estimation method and sliding window technique are adopted to estimate the PDF of tracking error and entropies. Due to the unknown process dynamics, the gradient of the objective function in a gradient-descent-type algorithm is estimated using an incremental perturbation method. The proposed approach is illustrated on a simulated WECS with non-Gaussian wind speed.

  6. Economic feasibility of reequipment terms based on profitability criterion

    Directory of Open Access Journals (Sweden)

    D.V. Bezugla

    2015-03-01

    Full Text Available The aim of the article. The aim of the research is to improve the methodological approaches to a priori determining the initial indices of profitability of technological equipment to solve the dynamic optimization task over time of industry technical re-equipment. The results of the analysis. One of the effective mechanisms to ground the industry technical re-equipment and to substitute threadbare machinery is the dynamic optimization method, but it is necessary to improve methodological approaches to a priori determination of baseline data, particularly the profit value, being calculated concerning the entire production system function period. The suggested methodological approach and corresponding algorithm provide calculation the profit sum at a cost structure of production, being manufactured by technological equipment of certain age at defined year of it use regarding to time factors and economic. Annual production volume would be planned at the highest level of possible productivity for the technological equipment, taking into account its age. The production capacity is gradually decreasing from its initial value, even taking into account the execution of prophylactic, current and thorough repairs. Consequently formula for determining of summary profit of output production manufactured by concrete equipment is evidently its function dependence of profitability level, equipment productivity and the commodity unity cost. Concerning the commodity unity cost it is expedient to take into account it dependence on the predicted level of annual inflation. Determination of equipment productivity dynamics may be proposed on the basis of using amortization approaches to basic production assets. To define indexes of obsolescence condition and production suitability of technological equipment the yearly amortization norm would be calculated. As regards to mentioned indices may be confirmed their dependence on the group of factors – technical factors

  7. Groundwater subsidies and penalties to corn yield

    Science.gov (United States)

    Zipper, S. C.; Booth, E.; Loheide, S. P.

    2013-12-01

    Proper water management is critical to closing yield gaps (observed yield below potential yield) as global populations continue to expand. However, the impacts of shallow groundwater on crop production and surface processes are poorly understood. The presence of groundwater within or just below the root zone has the potential to cause (via oxygen stress in poorly drained soils) or eliminate (via water supply in dry regions) yield gaps. The additional water use by a plant in the presence of shallow groundwater, compared to free drainage conditions, is called the groundwater subsidy; the depth at which the groundwater subsidy is greatest is the optimal depth to groundwater (DTGW). In wet years or under very shallow water table conditions, the groundwater subsidy is likely to be negative due to increased oxygen stress, and can be thought of as a groundwater penalty. Understanding the spatial dynamics of groundwater subsidies/penalties and how they interact with weather is critical to making sustainable agricultural and land-use decisions under a range of potential climates. Here, we examine patterns of groundwater subsidies and penalties in two commercial cornfields in the Yahara River Watershed, an urbanizing agricultural watershed in south-central Wisconsin. Water table levels are generally rising in the region due to a long-term trend of increasing precipitation over the last several decades. Biophysical indicators tracked throughout both the 2012 and 2013 growing seasons show a strong response to variable groundwater levels on a field scale. Sections of the field with optimal DTGW exhibit consistently higher stomatal conductance rates, taller canopies and higher leaf area index, higher ET rates, and higher pollination success rates. Patterns in these biophysical lines of evidence allow us to pinpoint specific periods within the growing season that plants were experiencing either oxygen or water stress. Most importantly, groundwater subsidies and penalties are

  8. Sheath Criterion for a Collisional Electronegative Plasma Sheath in an Applied Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    邹秀; 刘惠平; 邱明辉; 孙骁航

    2011-01-01

    The sheath criterion for a collisional electronegative plasma sheath in an applied magnetic field is investigated.It is assumed that the system consists of hot electrons,hot negative ions and cold positive ions.The effect of an applied magnetic field on the sheath criterion is discussed.The results reveal that the magnetic field has effects on both the upper and lower limits,which cause the range of the ion Mach number to increase.In addition,the numerical calculations of the electronegative plasma sheath are carried out to demonstrate the effects of sheath criterion on the characteristics of the sheath.%The sheath criterion for a collisioned electronegative plasma sheath in an applied magnetic Geld is investigated. It is assumed that the system consists of hot electrons, hot negative ions and cold positive ions. The effect of an applied magnetic Reid on the sheath criterion is discussed. The results reveal that the magnetic field has effects on both the upper and lower limits, which cause the range of the ion Mach number to increase. In addition, the numerical calculations of the electronegative plasma sheath are carried out to demonstrate the effects of sheath criterion on the characteristics of the sheath.

  9. Failure Study of Composite Materials by the Yeh-Stratton Criterion

    Science.gov (United States)

    Yeh, Hsien-Yang; Richards, W. Lance

    1997-01-01

    The newly developed Yeh-Stratton (Y-S) Strength Criterion was used to study the failure of composite materials with central holes and normal cracks. To evaluate the interaction parameters for the Y-S failure theory, it is necessary to perform several biaxial loading tests. However, it is indisputable that the inhomogeneous and anisotropic nature of composite materials have made their own contribution to the complication of the biaxial testing problem. To avoid the difficulties of performing many biaxial tests and still consider the effects of the interaction term in the Y-S Criterion, a simple modification of the Y-S Criterion was developed. The preliminary predictions by the modified Y-S Criterion were relatively conservative compared to the testing data. Thus, the modified Y-S Criterion could be used as a design tool. To further understand the composite failure problem, an investigation of the damage zone in front of the crack tip coupled with the Y-S Criterion is imperative.

  10. Multiaxial fatigue criterion based on parameters from torsion and axial S-N curve

    Directory of Open Access Journals (Sweden)

    M. Margetin

    2016-07-01

    Full Text Available Multiaxial high cycle fatigue is a topic that concerns nearly all industrial domains. In recent years, a great deal of recommendations how to address problems with multiaxial fatigue life time estimation have been made and a huge progress in the field has been achieved. Until now, however, no universal criterion for multiaxial fatigue has been proposed. Addressing this situation, this paper offers a design of a new multiaxial criterion for high cycle fatigue. This criterion is based on critical plane search. Damage parameter consists of a combination of normal and shear stresses on a critical plane (which is a plane with maximal shear stress amplitude. Material parameters used in proposed criterion are obtained from torsion and axial S-N curves. Proposed criterion correctly calculates life time for boundary loading condition (pure torsion and pure axial loading. Application of proposed model is demonstrated on biaxial loading and the results are verified with testing program using specimens made from S355 steel. Fatigue material parameters for proposed criterion and multiple sets of data for different combination of axial and torsional loading have been obtained during the experiment.

  11. Genetic relationship between yield and yield components of maize

    Directory of Open Access Journals (Sweden)

    Nastasić Aleksandra

    2010-01-01

    Full Text Available One of the objectives of this paper was to determine relationship between grain yield and yield components, in S1 and HS progenies of one early synthetic maize population. Grain yield was in high significant, medium strong and strong association with all studied yield components, in both populations. The strongest correlation was recorded between grain yield and 1000-kernel weight (S1 progenies rg = 0.684; HS progenies rg = 0.633. Between other studied traits, the highest values of genotypic coefficient of correlations were found between 1000-kernel weight and kernel depth in S1 population, and 1000-kernel weight and ear length in HS population. Also, objective of this research was founding the direct and indirect effects of yield components on grain yield. Desirable, high significant influence on grain yield, in path coefficient analysis, was found for 1000-kernel weight and kernel row number, and in S1 and HS progenies, and for ear length in population of S1 progenies. Kernel depth has undesirable direct effect on grain yield, in both populations.

  12. A new design criterion and construction method for space-time trellis codes based on classification of error events

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The known design criterions of Space-Time Trellis Codes (STTC) on slow Rayleigh fading channel are rank, determinant and trace criterion. These criterions are not advantageous not only in operation but also in performance. With classifying the error events of STTC, a new criterion was presented on slow Rayleigh fading channels. Based on the criterion, an effective and straightforward multi-step method is proposed to construct codes with better performance. This method can reduce the computation of search to small enough. Simulation results show that the codes searched by computer have the same or even better performance than the reported codes.

  13. An Efficient Return Algorithm For Non-Associated Plasticity With Linear Yield Criteria In Principal Stress Space

    DEFF Research Database (Denmark)

    Clausen, Johan Christian; Damkilde, Lars; Andersen, Lars

    2007-01-01

    An efficient return algorithm for stress update in numerical plasticity computations is presented. The yield criterion must be linear in principal stress space and can be composed of any number of yield planes. Each of these yield planes may have an associated or non-associated flow rule....... The stress return and the formation of the constitutive matrix is carried out in principal stress space. Here the manipulations simplify and rely on geometrical arguments. The singularities arising at the intersection of yield planes are dealt with in a straightforward way also based on geometrical...

  14. Role of Yield Stress in Magma Rheology

    Science.gov (United States)

    Kurokawa, A.; Di Giuseppe, E.; Davaille, A.; Kurita, K.

    2012-04-01

    Magmas are essentially multiphase material composed of solid crystals, gaseous bubbles and silicate liquids. They exhibit various types of drastic change in rheology with variation of mutual volumetric fractions of the components. The nature of this variable rheology is a key factor in controlling dynamics of flowing magma through a conduit. Particularly the existence of yield stress in flowing magma is expected to control the wall friction and formation of density waves. As the volumetric fraction of solid phase increases yield stress emerges above the critical fraction. Several previous studies have been conducted to clarify this critical value of magmatic fluid both in numerical simulations and laboratory experiments ([Lejeune and Pascal, 1995], [Saar and Manga 2001], [Ishibashi and Sato 2010]). The obtained values range from 13.3 to 40 vol%, which display wide variation and associated change in rheology has not been clarified well. In this presentation we report physical mechanism of emergence of yield stress in suspension as well as the associated change in the rheology based on laboratory experiments using analog material. We utilized thermogel aqueous suspension as an analog material of multiphase magma. Thermogel, which is a commercial name for poly(N-isopropyl acrylamide) (PNIPAM) undergoes volumetric phase change at the temperature around 35C:below this temperature the gel phase absorbs water and swells while below this it expels water and its volume shrinks. Because of this the volumetric fraction of gel phase systematically changes with temperature and the concentration of gel powder. The viscosity measured at lower stress drastically decreases across this phase change with increasing temperature while the viscosity at higher stress does not exhibit large change across the transition. We have performed a series of rheological measurements focusing on the emergence of yield stress on this aqueous suspension. Since the definition of yield stress is not

  15. Effect of density and planting pattern on yield and yield

    Directory of Open Access Journals (Sweden)

    alireza yadavi

    2009-06-01

    Full Text Available In order to evaluate competition ability of Grain maize (Zea mays L. against redroot pigweed (Amaranthus retroflexus L. a field experiment was conducted at Esfahan on 2003. In this research the effect of corn spatial arrangement on yield and yield components of corn (647 Three Way Cross hybrids under different levels of redroot pigweed infestation was investigated. Treatments were arranged in a factorial split experiment based on RCBD with three replications. Factorial arrangement of corn densities (74000 and 111000 plant ha-1 and planting patterns (single row, rectangular twin row and zigzag twin row formed the main plots. Split-plots referred to pigweed densities (0, 4, 8 and 12 plant m-1. Results showed that both grain and biological yield of corn increased as corn density rates increased but rows number per cob, number of grains per row of cob and 1000 grains weight decreased. The effects of planting arrangement on yield and yield components despite rows grain in cob, 1000 seeds weight and harvest index were statistically significant. Corn grain yield and yield components decreased significantly by increasing pigweed density. The effect of redroot pigweed density on corn grain and biological yield loss was predicted using Cousence hyperbolic yield equation. It showed that maximum grain yield loss and biological yield loss happened in single row arrangement and low corn density. Rows number per cob and grain numbers per row in higher corn density treatment showed lower reduction slopes under pigweed competition. In addition, grain rows numbers per cob and corn harvest index in twin arrangement treatments decreased lower than single row treatment under pigweed competition. The results of this research indicated that corn competition ability against redroot pigweed could be increased using dense population (1/5 fold of general density and zigzag twin row arrangement.

  16. A meta-analysis of criterion effects for the Implicit Relational Assessment Procedure (IRAP) in the clinical domain.

    Science.gov (United States)

    Vahey, Nigel A; Nicholson, Emma; Barnes-Holmes, Dermot

    2015-09-01

    The Implicit Relational Assessment Procedure (IRAP) is a technique that is attracting a substantial body of research literature, particularly within the clinical domain. In response, the present paper outlines a meta-analysis of clinically-focused IRAP effects (N = 494) to provide the first estimate of how well such effects validate against their respective criterion variables in general. The meta-analysis incorporated clinically-focused IRAP effects from 15 studies yielding a large effect size, r¯ = .45, with a desirably narrow 95% credibility interval (.23, .67). The funnel plot and subsequent sensitivity analyses indicated that this meta-effect was not subject to publication bias. The present meta-effect is an estimate based upon an IRAP literature that is still evolving rapidly in the clinical domain, and so as per its accompanying credibility interval, all conclusions that follow are necessarily provisional even if bounded. Apart from the fact that the current meta-effect might be subject to inadvertent under- and/or over-estimations of the current literature, the present meta-effect might strengthen with further refinements of the IRAP. The current meta-effect provides the means to calculate what sample size would be required to achieve a statistical power of .80 when testing the criterion validity of clinically-focused IRAP effects using a given parametric statistic. For example, first-order Pearson correlations would hypothetically require an N of 29-37 for such purposes depending upon how conservatively over-estimation of the present meta-effect is controlled for. Overall, the IRAP compares favourably with alternative implicit measures in clinical psychology. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Systematics in delayed neutron yields

    Energy Technology Data Exchange (ETDEWEB)

    Ohsawa, Takaaki [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.

    1998-03-01

    An attempt was made to reproduce the systematic trend observed in the delayed neutron yields for actinides on the basis of the five-Gaussian representation of the fission yield together with available data sets for delayed neutron emission probability. It was found that systematic decrease in DNY for heavier actinides is mainly due to decrease of fission yields of precursors in the lighter side of the light fragment region. (author)

  18. Interdependence of yield and yield components of confectionary sunflower hybrids

    Directory of Open Access Journals (Sweden)

    Hladni Nada

    2011-01-01

    Full Text Available The two most important criteria for introducing new confectionary hybrids into production are high seed and protein yield. That is why it is important to find the traits that are measurable, and that at the same time show a strong correlation with seed and protein yield, so that they can be used as a criteria for confectionary hybrid breeding. Results achieved during 2008 at the locations Rimski Šančevi (Region of Vojvodina and Kula (Central Serbia show that the new confectionary hybrids are expressing higher seed yields in comparison to standards (Vranac and Cepko though with a lower seed oil content. A very strong positive correlation was determined between seed yield and seed protein content, kernel content and mass of 1000 seeds. A very strong positive correlation was determined between seed protein content, seed yield and mass of 1000 seeds, with protein yield. This indicates that seed yield, seed protein content and mass of 1000 seeds have a high influence on protein yield. The degree of interdependence between different traits is a sign of direction which is supposed to facilitate better planning of sunflower breeding program.

  19. Dynamic responses of concrete-filled steel tubular member under axial compression considering creep effect

    Science.gov (United States)

    Jiang, X. T.; Wang, Y. D.; Dai, C. H.; Ding, M.

    2017-08-01

    The finite element model of concrete-filled steel tubular member was established by the numerical analysis software considering material nonlinearity to analyze concrete creep effect on the dynamic responses of the member under axial compression and lateral impact. In the model, the constitutive model of core concrete is the plastic damage model, that of steel is the Von Mises yield criterion and kinematic hardening model, and the creep effect at different ages is equivalent to the change of concrete elastic modulus. Then the dynamic responses of concrete-filled steel tubular member considering creep effects was simulated, and the effects of creep on contact time, impact load, deflection, stress and strain were discussed. The fruits provide a scientific basis for the design of the impact resistance of concrete filled steel tubular members.

  20. Shear Yielding and Shear Jamming of Dense Hard Sphere Glasses

    Science.gov (United States)

    Urbani, Pierfrancesco; Zamponi, Francesco

    2017-01-01

    We investigate the response of dense hard sphere glasses to a shear strain in a wide range of pressures ranging from the glass transition to the infinite-pressure jamming point. The phase diagram in the density-shear strain plane is calculated analytically using the mean-field infinite-dimensional solution. We find that just above the glass transition, the glass generically yields at a finite shear strain. The yielding transition in the mean-field picture is a spinodal point in presence of disorder. At higher densities, instead, we find that the glass generically jams at a finite shear strain: the jamming transition prevents yielding. The shear yielding and shear jamming lines merge in a critical point, close to which the system yields at extremely large shear stress. Around this point, highly nontrivial yielding dynamics, characterized by system-spanning disordered fractures, is expected.

  1. Growth dynamics and yield of melon as influenced by nitrogen fertilizer Dinâmica do crescimento e da produtividade do melão em resposta ao fertilizante nitrogenado

    Directory of Open Access Journals (Sweden)

    María Teresa Castellanos

    2011-04-01

    Full Text Available Nitrogen (N is an important nutrient for melon (Cucumis melo L. production. However there is scanty information about the amount necessary to maintain an appropriate balance between growth and yield. Melon vegetative organs must develop sufficiently to intercept light and accumulate water and nutrients but it is also important to obtain a large reproductive-vegetative dry weight ratio to maximize the fruit yield. We evaluated the influence of different N amounts on the growth, production of dry matter and fruit yield of a melon 'Piel de sapo' type. A three-year field experiment was carried out from May to September. Melons were subjected to an irrigation depth of 100% crop evapotranspiration and to 11 N fertilization rates, ranging 11 to 393 kg ha-1 in the three years. The dry matter production of leaves and stems increased as the N amount increased. The dry matter of the whole plant was affected similarly, while the fruit dry matter decreased as the N amount was increased above 112, 93 and 95 kg ha-1, in 2005, 2006 and 2007, respectively. The maximum Leaf Area Index (LAI, 3.1, was obtained at 393 kg ha-1 of N. The lowest N supply reduced the fruit yield by 21%, while the highest increased the vegetative growth, LAI and Leaf Area Duration (LAD, but reduced yield by 24% relative to the N93 treatment. Excessive applications of N increase vegetative growth at the expense of reproductive growth. For this melon type, rates about 90-100 kg ha-1 of N are sufficient for adequate plant growth, development and maximum production. To obtain fruit yield close to the maximum, the leaf N concentration at the end of the crop cycle should be higher than 19.5 g kg-1.O nitrogênio (N é um nutriente importante para a produção de melão (Cucumis melo L., porém existe pouca informação sobre a quantidade necessária para se obter um balanço entre o crescimento e a produtividade. Os órgãos vegetativos do melão precisam se desenvolver suficientemente para

  2. Similarity transformed semiclassical dynamics

    Science.gov (United States)

    Van Voorhis, Troy; Heller, Eric J.

    2003-12-01

    In this article, we employ a recently discovered criterion for selecting important contributions to the semiclassical coherent state propagator [T. Van Voorhis and E. J. Heller, Phys. Rev. A 66, 050501 (2002)] to study the dynamics of many dimensional problems. We show that the dynamics are governed by a similarity transformed version of the standard classical Hamiltonian. In this light, our selection criterion amounts to using trajectories generated with the untransformed Hamiltonian as approximate initial conditions for the transformed boundary value problem. We apply the new selection scheme to some multidimensional Henon-Heiles problems and compare our results to those obtained with the more sophisticated Herman-Kluk approach. We find that the present technique gives near-quantitative agreement with the the standard results, but that the amount of computational effort is less than Herman-Kluk requires even when sophisticated integral smoothing techniques are employed in the latter.

  3. Contribution of criterion A2 to PTSD screening in the presence of traumatic events.

    Science.gov (United States)

    Pereda, Noemí; Forero, Carlos G

    2012-10-01

    Criterion A2 according to the Diagnostic and Statistical Manual of Mental Disorders (4(th) ed.; DSM-IV; American Psychiatric Association [APA], 1994) for posttraumatic stress disorder (PTSD) aims to assess the individual's subjective appraisal of an event, but it has been claimed that it might not be sufficiently specific for diagnostic purposes. We analyse the contribution of Criterion A2 and DSM-IV criteria to detect PTSD for the most distressing life events experienced by our subjects. Young adults (N = 1,033) reported their most distressing life events, together with PTSD criteria (Criteria A2, B, C, D, E, and F). PTSD prevalence and criterion specificity and agreement with probable diagnoses were estimated. Our results indicate 80.30% of the individuals experienced traumatic events and met one or more PTSD criteria; 13.22% cases received a positive diagnosis of PTSD. Criterion A2 showed poor agreement with the final probable PTSD diagnosis (correlation with PTSD .13, specificity = .10); excluding it from PTSD diagnosis did not the change the estimated disorder prevalence significantly. Based on these findings it appears that Criterion A2 is scarcely specific and provides little information to confirm a probable PTSD case.

  4. Analytical investigation of an isomerization system using the resonance overlap criterion

    Science.gov (United States)

    Fukuda, Hiroya; Petrosky, Tomio; Konishi, Tetsuro

    2016-09-01

    An analytical procedure to obtain the volume of reactive initial condition in the reactant well is described. The applicability of the well-known Chirikov resonance overlap criterion is tested to determine the boundary between the reactive and unreactive regions of phase space in the reactant well for a classical Hamiltonian system with symmetric double-well potential coupled with a harmonic oscillator. As usual, the system is reduced to the two-dimensional whisker mapping in order to apply the overlap criterion. For the calculation process, the applicability of the overlap criterion is examined in cases where up to period-n (n=1,2,3) resonances are included in the criterion. Theoretical results are compared to numerical simulation through the Davis-Gray unimolecular reaction rate constant. It is found that Chirikov's criterion led to a bad estimation for lower periods up to n=2, but produced a reliable estimation after taking into account higher periods with n=3. However, there are some situations where the agreement including n=3 is still not good. The reasons for this disagreement and the possibilities for improvement of the calculation accuracy are discussed.

  5. Accuracy of a selection criterion for glass forming ability in the Ni–Nb–Zr system

    Energy Technology Data Exchange (ETDEWEB)

    Déo, L.P., E-mail: leonardopratavieira@gmail.com; Oliveira, M.F. de, E-mail: falcao@sc.usp.br

    2014-12-05

    Highlights: • We applied a selection in the Ni–Nb–Zr system to find alloys with high GFA. • We used the thermal parameter γ{sub m} to evaluate the GFA of alloys. • The correlation between the γ{sub m} parameter and R{sub c} in the studied system is poor. • The effect of oxygen impurity reduced dramatically the GFA of alloys. • Unknown intermetallic compounds reduced the accuracy of the criterion. - Abstract: Several theories have been developed and applied in metallic systems in order to find the best stoichiometries with high glass forming ability; however there is no universal theory to predict the glass forming ability in metallic systems. Recently a selection criterion was applied in the Zr–Ni–Cu system and it was found some correlation between experimental and theoretical data. This criterion correlates critical cooling rate for glass formation with topological instability of stable crystalline structures; average work function difference and average electron density difference among the constituent elements of the alloy. In the present work, this criterion was applied in the Ni–Nb–Zr system. It was investigated the influence of factors not considered in the calculation and on the accuracy of the criterion, such as unknown intermetallic compounds and oxygen contamination. Bulk amorphous specimens were produced by injection casting. The amorphous nature was analyzed by X-ray diffraction and differential scanning calorimetry; oxygen contamination was quantified by the inert gas fusion method.

  6. Quality criterion to optimize separations in capillary electrophoresis: Application to the analysis of harmala alkaloids.

    Science.gov (United States)

    Tascon, Marcos; Benavente, Fernando; Castells, Cecilia B; Gagliardi, Leonardo G

    2016-08-19

    In capillary electrophoresis (CE), resolution (Rs) and selectivity (α) are criteria often used in practice to optimize separations. Nevertheless, when these and other proposed parameters are considered as an elementary criterion for optimization by mathematical maximization, certain issues and inconsistencies appear. In the present work we analyzed the pros and cons of using these parameters as elementary criteria for mathematical optimization of capillary electrophoretic separations. We characterized the requirements of an ideal criterion to qualify separations within the framework of mathematical optimizations and, accordingly, propose: -1- a new elementary criterion (t') and -2- a method to extend this elementary criterion to compose a global function that simultaneously qualifies many different aspects, also called multicriteria optimization function (MCOF). In order to demonstrate this new concept, we employed a group of six alkaloids with closely related structures (harmine, harmaline, harmol, harmalol, harmane and norharmane). On the basis of this system, we present a critical comparison between the new optimization criterion t' and the former elementary criteria. Finally, aimed at validating the proposed methods, we composed an MCOF in which the capillary-electrophoretic separation of the six model compounds is mathematically optimized as a function of pH as the unique variable. Experimental results subsequently confirmed the accuracy of the model.

  7. Covariance-Based Measurement Selection Criterion for Gaussian-Based Algorithms

    Directory of Open Access Journals (Sweden)

    Fernando A. Auat Cheein

    2013-01-01

    Full Text Available Process modeling by means of Gaussian-based algorithms often suffers from redundant information which usually increases the estimation computational complexity without significantly improving the estimation performance. In this article, a non-arbitrary measurement selection criterion for Gaussian-based algorithms is proposed. The measurement selection criterion is based on the determination of the most significant measurement from both an estimation convergence perspective and the covariance matrix associated with the measurement. The selection criterion is independent from the nature of the measured variable. This criterion is used in conjunction with three Gaussian-based algorithms: the EIF (Extended Information Filter, the EKF (Extended Kalman Filter and the UKF (Unscented Kalman Filter. Nevertheless, the measurement selection criterion shown herein can also be applied to other Gaussian-based algorithms. Although this work is focused on environment modeling, the results shown herein can be applied to other Gaussian-based algorithm implementations. Mathematical descriptions and implementation results that validate the proposal are also included in this work.

  8. Life estimation by varying the critical plane orientation in the modified Carpinteri-Spagnoli criterion

    Directory of Open Access Journals (Sweden)

    Camilla Ronchei

    2015-10-01

    Full Text Available The modified Carpinteri-Spagnoli (C-S criterion is a multiaxial high-cycle fatigue criterion based on the critical plane approach. According to such a criterion, the orientation of the critical plane is linked to both the averaged directions of the principal stress axes and the fatigue properties of the material. The latter dependence is taken into account through a rotational angle, . Then, the multiaxial fatigue strength estimation is performed by computing an equivalent stress amplitude on the critical plane. In the present paper, some modifications of the original  expression are implemented in the modified C-S criterion. More precisely, such modified expressions of  depend on the ratio between the fatigue limit under fully reversed shear stress and that under fully reversed normal stress (in accordance with the original expression, and can be employed for metals ranging from mild to very hard fatigue behaviour. Some experimental data available in the literature are compared with the theoretical results in order to verify if the modified expressions are able to improve the fatigue strength estimation capability of the modified C-S criterion

  9. Formability Prediction of Advanced High Strength Steel with a New Ductile Fracture Criterion

    Science.gov (United States)

    Lou, Yanshan; Lim, Sungjun; Huh, Jeehyang; Huh, Hoon

    2011-08-01

    A ductile fracture criterion is newly proposed to accurately predict forming limit diagrams (FLD) of sheet metals. The new ductile fracture criterion is based on the effect of the non-dimensional stress triaxiality, the stress concentration factor and the effective plastic strain on the nucleation, growth and coalescence of voids. The new ductile fracture criterion has been applied to estimate the formability of four kind advanced high strength steels (AHSS): DP780, DP980, TRIP590, and TWIP980. FLDs predicted are compared with experimental results and those predicted by other ductile fracture criteria. The comparison demonstrates that FLDs predicted by the new ductile fracture criterion are in better agreement with experimental FLDs than those predicted by other ductile fracture criteria. The better agreement of FLDs predicted by the new ductile fracture criterion is because conventional ductile fracture criteria were proposed for fracture prediction in bulk metal forming while the new one is proposed to predict the onset of fracture in sheet metal forming processes.

  10. PTSD's risky behavior criterion: Relation with DSM-5 PTSD symptom clusters and psychopathology.

    Science.gov (United States)

    Contractor, Ateka A; Weiss, Nicole H; Dranger, Paula; Ruggero, Camilo; Armour, Cherie

    2017-06-01

    A new symptom criterion of reckless and self-destructive behaviors (E2) was recently added to posttraumatic stress disorder's (PTSD) diagnostic criteria in DSM-5, which is unsurprising given the well-established relation between PTSD and risky behaviors. Researchers have questioned the significance and incremental validity of this symptom criterion within PTSD's symptomatology. Unprecedented to our knowledge, we aim to compare trauma-exposed groups differing on their endorsement status of the risky behavior symptom on several psychopathology constructs (PTSD, depression, distress tolerance, rumination, anger). The sample included 123 trauma-exposed participants seeking mental health treatment (M age=35.70; 68.30% female) who completed self-report questionnaires assessing PTSD symptoms, depression, rumination, distress tolerance, and anger. Results of independent samples t-tests indicated that participants who endorsed the E2 criterion at a clinically significant level reported significantly greater PTSD subscale severity; depression severity; rumination facets of repetitive thoughts, counterfactual thinking, and problem-focused thinking; and anger reactions; and significantly less absorption and regulation (distress tolerance facets) compared to participants who did not endorse the E2 criterion at a clinically significant level. Results indicate the utility of the E2 criterion in identifying trauma-exposed individual with greater posttraumatic distress, and emphasize the importance of targeting such behaviors in treatment. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  11. Prediction of Shrinkage Pore Volume Fraction Using a Dimensionless Niyama Criterion

    Science.gov (United States)

    Carlson, Kent D.; Beckermann, Christoph

    2009-01-01

    A method is presented to use a dimensionless form of the well-known Niyama criterion to directly predict the amount of shrinkage porosity that forms during solidification of metal alloy castings. The main advancement offered by this method is that it avoids the need to know the threshold Niyama value below which shrinkage porosity forms; such threshold values are generally unknown and alloy dependent. The dimensionless criterion accounts for both the local thermal conditions (as in the original Niyama criterion) and the properties and solidification characteristics of the alloy. Once a dimensionless Niyama criterion value is obtained from casting simulation results, the corresponding shrinkage pore volume fraction can be determined knowing only the solid fraction-temperature curve and the total solidification shrinkage of the alloy. Curves providing the shrinkage pore volume percentage as a function of the dimensionless Niyama criterion are given for WCB steel, aluminum alloy A356, and magnesium alloy AZ91D. The present method is used in a general-purpose casting simulation software package to predict shrinkage porosity in three-dimensional (3-D) castings. Comparisons between simulated and experimental shrinkage porosity results for a WCB steel plate casting demonstrate that this method can reasonably predict shrinkage. Additional simulations for magnesium alloy AZ91D illustrate that this method is applicable to a wide variety of alloys and casting conditions.

  12. Relationship between Carbon Isotope Discrimination and Grain Yield in Spring Wheat Cultivated under Different Water Regimes

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In C3 plants, carbon isotope discrimination (△) has been proposed as an indirect selection criterion for grain yield. Reported correlations between △ and grain yield however, differ highly according to the analyzed organ or tissue, the stage of sampling, and the environment and water regime. In a first experiment carried out in spring wheat during two consecutive seasons in the dry conditions of northwest Mexico (Ciudad Obregon, Sonora), different water treatments were applied,corresponding to the main water regimes available to spring wheat worldwide, and the relationships between △ values of different organs and grain yield were examined. Under terminal (post-anthesis) water stress, grain yield was positively associated with △ in grain at maturity and in leaf at anthesis, confirming results previously obtained under Mediterranean environments. Under early (pre-anthesis) water stress and residual moisture stress, the association between grain △ and yield was weaker and highly depended on the quantity of water stored in the soil at sowing. No correlation was found between △ and grain yield under optimal irrigation. The relationship between △ and grain yield was also studied during two consecutive seasons in 20 bread wheat cultivars in the Ningxia region (Northern China), characterized by winter drought(pre-anthesis water stress). Wheat was grown under rainfed conditions in two locations (Guyuan and Pengyang) and under irrigated conditions in another two (Yinchuan and Huinong). In Huinong, the crop was also exposed to salt stress.Highly significant positive associations were found between leaf and grain △ and grain yields across the environments.The relationship between △ and yield within environments highly depended on the quantity of water stored in the soil at sowing, the quantity and distribution of rainfall during the growth cycle, the presence of salt in the soil, and the occurrence of irrigation before anthesis. These two experiments

  13. Specific yield: compilation of specific yields for various materials

    Science.gov (United States)

    Johnson, A.I.

    1967-01-01

    Specific yield is defined as the ratio of (1) the volume of water that a saturated rock or soil will yield by gravity to (2) the total volume of the rock or soft. Specific yield is usually expressed as a percentage. The value is not definitive, because the quantity of water that will drain by gravity depends on variables such as duration of drainage, temperature, mineral composition of the water, and various physical characteristics of the rock or soil under consideration. Values of specific yields nevertheless offer a convenient means by which hydrologists can estimate the water-yielding capacities of earth materials and, as such, are very useful in hydrologic studies. The present report consists mostly of direct or modified quotations from many selected reports that present and evaluate methods for determining specific yield, limitations of those methods, and results of the determinations made on a wide variety of rock and soil materials. Although no particular values are recommended in this report, a table summarizes values of specific yield, and their averages, determined for 10 rock textures. The following is an abstract of the table. [Table

  14. Coiling of yield stress fluids

    NARCIS (Netherlands)

    Y. Rahmani; M. Habibi; A. Javadi; D. Bonn

    2011-01-01

    We present an experimental investigation of the coiling of a filament of a yield stress fluid falling on a solid surface. We use two kinds of yield stress fluids, shaving foam and hair gel, and show that the coiling of the foam is similar to the coiling of an elastic rope. Two regimes of coiling (el

  15. Yield gaps in oil palm

    NARCIS (Netherlands)

    Woittiez, Lotte S.; Wijk, van Mark T.; Slingerland, Maja; Noordwijk, van Meine; Giller, Ken E.

    2017-01-01

    Oil palm, currently the world's main vegetable oil crop, is characterised by a large productivity and a long life span (≥25 years). Peak oil yields of 12 t ha−1 yr−1 have been achieved in small plantations, and maximum theoretical yields as calculated with simulation models are 18.5 t oil ha−1 yr−1,

  16. Breeding for Grass Seed Yield

    DEFF Research Database (Denmark)

    Boelt, Birte; Studer, Bruno

    2010-01-01

    Seed yield is a trait of major interest for many fodder and amenity grass species and has received increasing attention since seed multiplication is economically relevant for novel grass cultivars to compete in the commercial market. Although seed yield is a complex trait and affected...... by agricultural practices as well as environmental factors, traits related to seed production reveal considerable genetic variation, prerequisite for improvement by direct or indirect selection. This chapter first reports on the biological and physiological basics of the grass reproduction system, then highlights...... important aspects and components affecting the seed yield potential and the agronomic and environmental aspects affecting the utilization and realization of the seed yield potential. Finally, it discusses the potential of plant breeding to sustainably improve total seed yield in fodder and amenity grasses....

  17. A Simple Isolation Criterion based on 3D Redshift Space Mapping

    CERN Document Server

    Spector, Oded

    2009-01-01

    We selected a sample of galaxies, extremely isolated in 3D redshift space, based on data from NED and the ongoing ALFALFA HI (21cm) survey. A simple selection criterion was employed: having no neighbors closer than 300 km/s in 3D redshift space. The environments of galaxies, selected using this criterion and NED data alone, were analyzed theoretically using a constrained simulation of the local Universe, and were found to be an order of magnitude less dense than environments around randomly selected galaxies. One third of the galaxies selected using NED data alone did not pass the criterion when tested with ALFALFA data, implying that the use of unbiased HI data significantly improves the quality of the sample.

  18. Relative blindsight arises from a criterion confound in metacontrast masking: implications for theories of consciousness.

    Science.gov (United States)

    Jannati, Ali; Di Lollo, Vincent

    2012-03-01

    Relative blindsight is said to occur when different levels of subjective awareness are obtained at equality of objective performance. Using metacontrast masking, Lau and Passingham (2006) reported relative blindsight in normal observers at the shorter of two stimulus-onset asynchronies (SOAs) between target and mask. Experiment 1 replicated the critical asymmetry in subjective awareness at equality of objective performance. We argue that this asymmetry cannot be regarded as evidence for relative blindsight because the observers' responses were based on different attributes of the stimuli (criterion contents) at the two SOAs. With an invariant criterion content (Experiment 2), there was no asymmetry in subjective awareness across the two SOAs even though objective performance was the same. Experiment 3 examined the effect of criterion level on estimates of relative blindsight. Collectively, the present results question whether metacontrast masking is a suitable paradigm for establishing relative blindsight. Implications for theories of consciousness are discussed. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. A MIXED MODE FRACTURE CRITERION BASED ON THE MAXIMUM TANGENTIAL STRESS IN BRITTLE INCLUSION

    Institute of Scientific and Technical Information of China (English)

    Ji Changjiang; Li Zhonghua; Sun Jun

    2005-01-01

    A closed-form solution for predicting the tangential stress of an inclusion located in mixed mode Ⅰ and Ⅱ crack tip field was developed based on the Eshelby equivalent inclusion theory. Then a mixed mode fracture criterion, including the fracture direction and the critical load, was established based on the maximum tangential stress in the inclusion for brittle inclusioninduced fracture materials. The proposed fracture criterion is a function of the inclusion fracture stress, its size and volume fraction, as well as the elastic constants of the inclusion and the matrix material. The present criterion will reduce to the conventional one as the inclusion having the same elastic behavior as the matrix material. The proposed solutions are in good agreement with detailed finite element analysis and measurement.

  20. Rayleigh Number Criterion for Formation of A-Segregates in Steel Castings and Ingots

    DEFF Research Database (Denmark)

    Rad, M. Torabi; Kotas, Petr; Beckermann, C.

    2013-01-01

    A Rayleigh number-based criterion is developed for predicting the formation of A-segregates in steel castings and ingots. The criterion is calibrated using available experimental data for ingots involving 27 different steel compositions. The critical Rayleigh number above which A-segregates can...... be expected to form is found to be 17 ± 8. The primary source of uncertainty in this critical value is the dendrite arm spacing. The Rayleigh number criterion of the current study is implemented in a casting simulation code and used to predict A-segregates in three case studies involving steel sand castings......, the primary reason for this over-prediction is persumed to be the presence of a central zone of equiaxed grains in the casting sections. A-segregates do not form when the grain structure is equiaxed. © The Minerals, Metals & Materials Society and ASM International 2013...